1 # SPDX-License-Identifier: GPL-2.0+
3 # (C) Copyright 2000 - 2013
4 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
9 This directory contains the source code for U-Boot, a boot loader for
10 Embedded boards based on PowerPC, ARM, MIPS and several other
11 processors, which can be installed in a boot ROM and used to
12 initialize and test the hardware or to download and run application
15 The development of U-Boot is closely related to Linux: some parts of
16 the source code originate in the Linux source tree, we have some
17 header files in common, and special provision has been made to
18 support booting of Linux images.
20 Some attention has been paid to make this software easily
21 configurable and extendable. For instance, all monitor commands are
22 implemented with the same call interface, so that it's very easy to
23 add new commands. Also, instead of permanently adding rarely used
24 code (for instance hardware test utilities) to the monitor, you can
25 load and run it dynamically.
31 In general, all boards for which a configuration option exists in the
32 Makefile have been tested to some extent and can be considered
33 "working". In fact, many of them are used in production systems.
35 In case of problems see the CHANGELOG file to find out who contributed
36 the specific port. In addition, there are various MAINTAINERS files
37 scattered throughout the U-Boot source identifying the people or
38 companies responsible for various boards and subsystems.
40 Note: As of August, 2010, there is no longer a CHANGELOG file in the
41 actual U-Boot source tree; however, it can be created dynamically
42 from the Git log using:
50 In case you have questions about, problems with or contributions for
51 U-Boot, you should send a message to the U-Boot mailing list at
52 <u-boot@lists.denx.de>. There is also an archive of previous traffic
53 on the mailing list - please search the archive before asking FAQ's.
54 Please see https://lists.denx.de/pipermail/u-boot and
55 https://marc.info/?l=u-boot
57 Where to get source code:
58 =========================
60 The U-Boot source code is maintained in the Git repository at
61 https://source.denx.de/u-boot/u-boot.git ; you can browse it online at
62 https://source.denx.de/u-boot/u-boot
64 The "Tags" links on this page allow you to download tarballs of
65 any version you might be interested in. Official releases are also
66 available from the DENX file server through HTTPS or FTP.
67 https://ftp.denx.de/pub/u-boot/
68 ftp://ftp.denx.de/pub/u-boot/
74 - start from 8xxrom sources
75 - create PPCBoot project (https://sourceforge.net/projects/ppcboot)
77 - make it easier to add custom boards
78 - make it possible to add other [PowerPC] CPUs
79 - extend functions, especially:
80 * Provide extended interface to Linux boot loader
83 * ATA disk / SCSI ... boot
84 - create ARMBoot project (https://sourceforge.net/projects/armboot)
85 - add other CPU families (starting with ARM)
86 - create U-Boot project (https://sourceforge.net/projects/u-boot)
87 - current project page: see https://www.denx.de/wiki/U-Boot
93 The "official" name of this project is "Das U-Boot". The spelling
94 "U-Boot" shall be used in all written text (documentation, comments
95 in source files etc.). Example:
97 This is the README file for the U-Boot project.
99 File names etc. shall be based on the string "u-boot". Examples:
101 include/asm-ppc/u-boot.h
103 #include <asm/u-boot.h>
105 Variable names, preprocessor constants etc. shall be either based on
106 the string "u_boot" or on "U_BOOT". Example:
108 U_BOOT_VERSION u_boot_logo
109 IH_OS_U_BOOT u_boot_hush_start
115 Starting with the release in October 2008, the names of the releases
116 were changed from numerical release numbers without deeper meaning
117 into a time stamp based numbering. Regular releases are identified by
118 names consisting of the calendar year and month of the release date.
119 Additional fields (if present) indicate release candidates or bug fix
120 releases in "stable" maintenance trees.
123 U-Boot v2009.11 - Release November 2009
124 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
125 U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release
131 /arch Architecture-specific files
132 /arc Files generic to ARC architecture
133 /arm Files generic to ARM architecture
134 /m68k Files generic to m68k architecture
135 /microblaze Files generic to microblaze architecture
136 /mips Files generic to MIPS architecture
137 /nds32 Files generic to NDS32 architecture
138 /nios2 Files generic to Altera NIOS2 architecture
139 /powerpc Files generic to PowerPC architecture
140 /riscv Files generic to RISC-V architecture
141 /sandbox Files generic to HW-independent "sandbox"
142 /sh Files generic to SH architecture
143 /x86 Files generic to x86 architecture
144 /xtensa Files generic to Xtensa architecture
145 /api Machine/arch-independent API for external apps
146 /board Board-dependent files
147 /boot Support for images and booting
148 /cmd U-Boot commands functions
149 /common Misc architecture-independent functions
150 /configs Board default configuration files
151 /disk Code for disk drive partition handling
152 /doc Documentation (a mix of ReST and READMEs)
153 /drivers Device drivers
154 /dts Makefile for building internal U-Boot fdt.
155 /env Environment support
156 /examples Example code for standalone applications, etc.
157 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
158 /include Header Files
159 /lib Library routines generic to all architectures
160 /Licenses Various license files
162 /post Power On Self Test
163 /scripts Various build scripts and Makefiles
164 /test Various unit test files
165 /tools Tools to build and sign FIT images, etc.
167 Software Configuration:
168 =======================
170 Configuration is usually done using C preprocessor defines; the
171 rationale behind that is to avoid dead code whenever possible.
173 There are two classes of configuration variables:
175 * Configuration _OPTIONS_:
176 These are selectable by the user and have names beginning with
179 * Configuration _SETTINGS_:
180 These depend on the hardware etc. and should not be meddled with if
181 you don't know what you're doing; they have names beginning with
184 Previously, all configuration was done by hand, which involved creating
185 symbolic links and editing configuration files manually. More recently,
186 U-Boot has added the Kbuild infrastructure used by the Linux kernel,
187 allowing you to use the "make menuconfig" command to configure your
191 Selection of Processor Architecture and Board Type:
192 ---------------------------------------------------
194 For all supported boards there are ready-to-use default
195 configurations available; just type "make <board_name>_defconfig".
197 Example: For a TQM823L module type:
200 make TQM823L_defconfig
202 Note: If you're looking for the default configuration file for a board
203 you're sure used to be there but is now missing, check the file
204 doc/README.scrapyard for a list of no longer supported boards.
209 U-Boot can be built natively to run on a Linux host using the 'sandbox'
210 board. This allows feature development which is not board- or architecture-
211 specific to be undertaken on a native platform. The sandbox is also used to
212 run some of U-Boot's tests.
214 See doc/arch/sandbox.rst for more details.
217 Board Initialisation Flow:
218 --------------------------
220 This is the intended start-up flow for boards. This should apply for both
221 SPL and U-Boot proper (i.e. they both follow the same rules).
223 Note: "SPL" stands for "Secondary Program Loader," which is explained in
224 more detail later in this file.
226 At present, SPL mostly uses a separate code path, but the function names
227 and roles of each function are the same. Some boards or architectures
228 may not conform to this. At least most ARM boards which use
229 CONFIG_SPL_FRAMEWORK conform to this.
231 Execution typically starts with an architecture-specific (and possibly
232 CPU-specific) start.S file, such as:
234 - arch/arm/cpu/armv7/start.S
235 - arch/powerpc/cpu/mpc83xx/start.S
236 - arch/mips/cpu/start.S
238 and so on. From there, three functions are called; the purpose and
239 limitations of each of these functions are described below.
242 - purpose: essential init to permit execution to reach board_init_f()
243 - no global_data or BSS
244 - there is no stack (ARMv7 may have one but it will soon be removed)
245 - must not set up SDRAM or use console
246 - must only do the bare minimum to allow execution to continue to
248 - this is almost never needed
249 - return normally from this function
252 - purpose: set up the machine ready for running board_init_r():
253 i.e. SDRAM and serial UART
254 - global_data is available
256 - BSS is not available, so you cannot use global/static variables,
257 only stack variables and global_data
259 Non-SPL-specific notes:
260 - dram_init() is called to set up DRAM. If already done in SPL this
264 - you can override the entire board_init_f() function with your own
266 - preloader_console_init() can be called here in extremis
267 - should set up SDRAM, and anything needed to make the UART work
268 - there is no need to clear BSS, it will be done by crt0.S
269 - for specific scenarios on certain architectures an early BSS *can*
270 be made available (via CONFIG_SPL_EARLY_BSS by moving the clearing
271 of BSS prior to entering board_init_f()) but doing so is discouraged.
272 Instead it is strongly recommended to architect any code changes
273 or additions such to not depend on the availability of BSS during
274 board_init_f() as indicated in other sections of this README to
275 maintain compatibility and consistency across the entire code base.
276 - must return normally from this function (don't call board_init_r()
279 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
280 this point the stack and global_data are relocated to below
281 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
285 - purpose: main execution, common code
286 - global_data is available
288 - BSS is available, all static/global variables can be used
289 - execution eventually continues to main_loop()
291 Non-SPL-specific notes:
292 - U-Boot is relocated to the top of memory and is now running from
296 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
297 CONFIG_SPL_STACK_R_ADDR points into SDRAM
298 - preloader_console_init() can be called here - typically this is
299 done by selecting CONFIG_SPL_BOARD_INIT and then supplying a
300 spl_board_init() function containing this call
301 - loads U-Boot or (in falcon mode) Linux
304 Configuration Options:
305 ----------------------
307 Configuration depends on the combination of board and CPU type; all
308 such information is kept in a configuration file
309 "include/configs/<board_name>.h".
311 Example: For a TQM823L module, all configuration settings are in
312 "include/configs/TQM823L.h".
315 Many of the options are named exactly as the corresponding Linux
316 kernel configuration options. The intention is to make it easier to
317 build a config tool - later.
319 - ARM Platform Bus Type(CCI):
320 CoreLink Cache Coherent Interconnect (CCI) is ARM BUS which
321 provides full cache coherency between two clusters of multi-core
322 CPUs and I/O coherency for devices and I/O masters
324 CONFIG_SYS_FSL_HAS_CCI400
326 Defined For SoC that has cache coherent interconnect
329 CONFIG_SYS_FSL_HAS_CCN504
331 Defined for SoC that has cache coherent interconnect CCN-504
333 The following options need to be configured:
335 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
337 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
342 Specifies that the core is a 64-bit PowerPC implementation (implements
343 the "64" category of the Power ISA). This is necessary for ePAPR
344 compliance, among other possible reasons.
346 CONFIG_SYS_FSL_TBCLK_DIV
348 Defines the core time base clock divider ratio compared to the
349 system clock. On most PQ3 devices this is 8, on newer QorIQ
350 devices it can be 16 or 32. The ratio varies from SoC to Soc.
352 CONFIG_SYS_FSL_PCIE_COMPAT
354 Defines the string to utilize when trying to match PCIe device
355 tree nodes for the given platform.
357 CONFIG_SYS_FSL_ERRATUM_A004510
359 Enables a workaround for erratum A004510. If set,
360 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
361 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
363 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
364 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
366 Defines one or two SoC revisions (low 8 bits of SVR)
367 for which the A004510 workaround should be applied.
369 The rest of SVR is either not relevant to the decision
370 of whether the erratum is present (e.g. p2040 versus
371 p2041) or is implied by the build target, which controls
372 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
374 See Freescale App Note 4493 for more information about
377 CONFIG_A003399_NOR_WORKAROUND
378 Enables a workaround for IFC erratum A003399. It is only
379 required during NOR boot.
381 CONFIG_A008044_WORKAROUND
382 Enables a workaround for T1040/T1042 erratum A008044. It is only
383 required during NAND boot and valid for Rev 1.0 SoC revision
385 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
387 This is the value to write into CCSR offset 0x18600
388 according to the A004510 workaround.
390 CONFIG_SYS_FSL_DSP_DDR_ADDR
391 This value denotes start offset of DDR memory which is
392 connected exclusively to the DSP cores.
394 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
395 This value denotes start offset of M2 memory
396 which is directly connected to the DSP core.
398 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
399 This value denotes start offset of M3 memory which is directly
400 connected to the DSP core.
402 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
403 This value denotes start offset of DSP CCSR space.
405 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
406 Single Source Clock is clocking mode present in some of FSL SoC's.
407 In this mode, a single differential clock is used to supply
408 clocks to the sysclock, ddrclock and usbclock.
410 CONFIG_SYS_CPC_REINIT_F
411 This CONFIG is defined when the CPC is configured as SRAM at the
412 time of U-Boot entry and is required to be re-initialized.
415 Indicates this SoC supports deep sleep feature. If deep sleep is
416 supported, core will start to execute uboot when wakes up.
418 - Generic CPU options:
419 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
421 Defines the endianess of the CPU. Implementation of those
422 values is arch specific.
425 Freescale DDR driver in use. This type of DDR controller is
426 found in mpc83xx, mpc85xx as well as some ARM core SoCs.
428 CONFIG_SYS_FSL_DDR_ADDR
429 Freescale DDR memory-mapped register base.
431 CONFIG_SYS_FSL_DDR_EMU
432 Specify emulator support for DDR. Some DDR features such as
433 deskew training are not available.
435 CONFIG_SYS_FSL_DDRC_GEN1
436 Freescale DDR1 controller.
438 CONFIG_SYS_FSL_DDRC_GEN2
439 Freescale DDR2 controller.
441 CONFIG_SYS_FSL_DDRC_GEN3
442 Freescale DDR3 controller.
444 CONFIG_SYS_FSL_DDRC_GEN4
445 Freescale DDR4 controller.
447 CONFIG_SYS_FSL_DDRC_ARM_GEN3
448 Freescale DDR3 controller for ARM-based SoCs.
451 Board config to use DDR1. It can be enabled for SoCs with
452 Freescale DDR1 or DDR2 controllers, depending on the board
456 Board config to use DDR2. It can be enabled for SoCs with
457 Freescale DDR2 or DDR3 controllers, depending on the board
461 Board config to use DDR3. It can be enabled for SoCs with
462 Freescale DDR3 or DDR3L controllers.
465 Board config to use DDR3L. It can be enabled for SoCs with
468 CONFIG_SYS_FSL_IFC_BE
469 Defines the IFC controller register space as Big Endian
471 CONFIG_SYS_FSL_IFC_LE
472 Defines the IFC controller register space as Little Endian
474 CONFIG_SYS_FSL_IFC_CLK_DIV
475 Defines divider of platform clock(clock input to IFC controller).
477 CONFIG_SYS_FSL_LBC_CLK_DIV
478 Defines divider of platform clock(clock input to eLBC controller).
480 CONFIG_SYS_FSL_DDR_BE
481 Defines the DDR controller register space as Big Endian
483 CONFIG_SYS_FSL_DDR_LE
484 Defines the DDR controller register space as Little Endian
486 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
487 Physical address from the view of DDR controllers. It is the
488 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
489 it could be different for ARM SoCs.
491 CONFIG_SYS_FSL_DDR_INTLV_256B
492 DDR controller interleaving on 256-byte. This is a special
493 interleaving mode, handled by Dickens for Freescale layerscape
496 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
497 Number of controllers used as main memory.
499 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
500 Number of controllers used for other than main memory.
502 CONFIG_SYS_FSL_HAS_DP_DDR
503 Defines the SoC has DP-DDR used for DPAA.
505 CONFIG_SYS_FSL_SEC_BE
506 Defines the SEC controller register space as Big Endian
508 CONFIG_SYS_FSL_SEC_LE
509 Defines the SEC controller register space as Little Endian
512 CONFIG_SYS_INIT_SP_OFFSET
514 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
515 pointer. This is needed for the temporary stack before
518 CONFIG_XWAY_SWAP_BYTES
520 Enable compilation of tools/xway-swap-bytes needed for Lantiq
521 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
522 be swapped if a flash programmer is used.
525 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
527 Select high exception vectors of the ARM core, e.g., do not
528 clear the V bit of the c1 register of CP15.
531 Generic timer clock source frequency.
533 COUNTER_FREQUENCY_REAL
534 Generic timer clock source frequency if the real clock is
535 different from COUNTER_FREQUENCY, and can only be determined
539 CONFIG_TEGRA_SUPPORT_NON_SECURE
541 Support executing U-Boot in non-secure (NS) mode. Certain
542 impossible actions will be skipped if the CPU is in NS mode,
543 such as ARM architectural timer initialization.
545 - Linux Kernel Interface:
546 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
548 When transferring memsize parameter to Linux, some versions
549 expect it to be in bytes, others in MB.
550 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
554 New kernel versions are expecting firmware settings to be
555 passed using flattened device trees (based on open firmware
559 * New libfdt-based support
560 * Adds the "fdt" command
561 * The bootm command automatically updates the fdt
563 OF_TBCLK - The timebase frequency.
565 boards with QUICC Engines require OF_QE to set UCC MAC
568 CONFIG_OF_BOARD_SETUP
570 Board code has addition modification that it wants to make
571 to the flat device tree before handing it off to the kernel
573 CONFIG_OF_SYSTEM_SETUP
575 Other code has addition modification that it wants to make
576 to the flat device tree before handing it off to the kernel.
577 This causes ft_system_setup() to be called before booting
582 U-Boot can detect if an IDE device is present or not.
583 If not, and this new config option is activated, U-Boot
584 removes the ATA node from the DTS before booting Linux,
585 so the Linux IDE driver does not probe the device and
586 crash. This is needed for buggy hardware (uc101) where
587 no pull down resistor is connected to the signal IDE5V_DD7.
589 - vxWorks boot parameters:
591 bootvx constructs a valid bootline using the following
592 environments variables: bootdev, bootfile, ipaddr, netmask,
593 serverip, gatewayip, hostname, othbootargs.
594 It loads the vxWorks image pointed bootfile.
596 Note: If a "bootargs" environment is defined, it will override
597 the defaults discussed just above.
599 - Cache Configuration:
600 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
602 - Cache Configuration for ARM:
603 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
605 CONFIG_SYS_PL310_BASE - Physical base address of PL310
606 controller register space
611 If you have Amba PrimeCell PL011 UARTs, set this variable to
612 the clock speed of the UARTs.
616 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
617 define this to a list of base addresses for each (supported)
618 port. See e.g. include/configs/versatile.h
620 CONFIG_SERIAL_HW_FLOW_CONTROL
622 Define this variable to enable hw flow control in serial driver.
623 Current user of this option is drivers/serial/nsl16550.c driver
625 - Serial Download Echo Mode:
627 If defined to 1, all characters received during a
628 serial download (using the "loads" command) are
629 echoed back. This might be needed by some terminal
630 emulations (like "cu"), but may as well just take
631 time on others. This setting #define's the initial
632 value of the "loads_echo" environment variable.
634 - Removal of commands
635 If no commands are needed to boot, you can disable
636 CONFIG_CMDLINE to remove them. In this case, the command line
637 will not be available, and when U-Boot wants to execute the
638 boot command (on start-up) it will call board_run_command()
639 instead. This can reduce image size significantly for very
640 simple boot procedures.
642 - Regular expression support:
644 If this variable is defined, U-Boot is linked against
645 the SLRE (Super Light Regular Expression) library,
646 which adds regex support to some commands, as for
647 example "env grep" and "setexpr".
651 If this variable is defined, U-Boot will use a device tree
652 to configure its devices, instead of relying on statically
653 compiled #defines in the board file. This option is
654 experimental and only available on a few boards. The device
655 tree is available in the global data as gd->fdt_blob.
657 U-Boot needs to get its device tree from somewhere. This can
658 be done using one of the three options below:
661 If this variable is defined, U-Boot will build a device tree
662 binary. It will be called u-boot.dtb. Architecture-specific
663 code will locate it at run-time. Generally this works by:
665 cat u-boot.bin u-boot.dtb >image.bin
667 and in fact, U-Boot does this for you, creating a file called
668 u-boot-dtb.bin which is useful in the common case. You can
669 still use the individual files if you need something more
673 If this variable is defined, U-Boot will use the device tree
674 provided by the board at runtime instead of embedding one with
675 the image. Only boards defining board_fdt_blob_setup() support
676 this option (see include/fdtdec.h file).
680 If this variable is defined, it enables watchdog
681 support for the SoC. There must be support in the SoC
682 specific code for a watchdog. For the 8xx
683 CPUs, the SIU Watchdog feature is enabled in the SYPCR
684 register. When supported for a specific SoC is
685 available, then no further board specific code should
689 When using a watchdog circuitry external to the used
690 SoC, then define this variable and provide board
691 specific code for the "hw_watchdog_reset" function.
693 CONFIG_SYS_WATCHDOG_FREQ
694 Some platforms automatically call WATCHDOG_RESET()
695 from the timer interrupt handler every
696 CONFIG_SYS_WATCHDOG_FREQ interrupts. If not set by the
697 board configuration file, a default of CONFIG_SYS_HZ/2
698 (i.e. 500) is used. Setting CONFIG_SYS_WATCHDOG_FREQ
699 to 0 disables calling WATCHDOG_RESET() from the timer
704 When CONFIG_CMD_DATE is selected, the type of the RTC
705 has to be selected, too. Define exactly one of the
708 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
709 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
710 CONFIG_RTC_MC146818 - use MC146818 RTC
711 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
712 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
713 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
714 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
715 CONFIG_RTC_DS164x - use Dallas DS164x RTC
716 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
717 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
718 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
719 CONFIG_SYS_RV3029_TCR - enable trickle charger on
722 Note that if the RTC uses I2C, then the I2C interface
723 must also be configured. See I2C Support, below.
726 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
728 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
729 chip-ngpio pairs that tell the PCA953X driver the number of
730 pins supported by a particular chip.
732 Note that if the GPIO device uses I2C, then the I2C interface
733 must also be configured. See I2C Support, below.
736 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
737 accesses and can checksum them or write a list of them out
738 to memory. See the 'iotrace' command for details. This is
739 useful for testing device drivers since it can confirm that
740 the driver behaves the same way before and after a code
741 change. Currently this is supported on sandbox and arm. To
742 add support for your architecture, add '#include <iotrace.h>'
743 to the bottom of arch/<arch>/include/asm/io.h and test.
745 Example output from the 'iotrace stats' command is below.
746 Note that if the trace buffer is exhausted, the checksum will
747 still continue to operate.
750 Start: 10000000 (buffer start address)
751 Size: 00010000 (buffer size)
752 Offset: 00000120 (current buffer offset)
753 Output: 10000120 (start + offset)
754 Count: 00000018 (number of trace records)
755 CRC32: 9526fb66 (CRC32 of all trace records)
759 When CONFIG_TIMESTAMP is selected, the timestamp
760 (date and time) of an image is printed by image
761 commands like bootm or iminfo. This option is
762 automatically enabled when you select CONFIG_CMD_DATE .
764 - Partition Labels (disklabels) Supported:
765 Zero or more of the following:
766 CONFIG_MAC_PARTITION Apple's MacOS partition table.
767 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
768 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
769 bootloader. Note 2TB partition limit; see
771 CONFIG_SCSI) you must configure support for at
772 least one non-MTD partition type as well.
775 CONFIG_IDE_RESET - is this is defined, IDE Reset will
776 be performed by calling the function
777 ide_set_reset(int reset)
778 which has to be defined in a board specific file
783 Set this to enable ATAPI support.
788 Set this to enable support for disks larger than 137GB
789 Also look at CONFIG_SYS_64BIT_LBA.
790 Whithout these , LBA48 support uses 32bit variables and will 'only'
791 support disks up to 2.1TB.
793 CONFIG_SYS_64BIT_LBA:
794 When enabled, makes the IDE subsystem use 64bit sector addresses.
798 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
799 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
800 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
801 maximum numbers of LUNs, SCSI ID's and target
804 The environment variable 'scsidevs' is set to the number of
805 SCSI devices found during the last scan.
807 - NETWORK Support (PCI):
809 Utility code for direct access to the SPI bus on Intel 8257x.
810 This does not do anything useful unless you set at least one
811 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
814 Support for National dp83815 chips.
817 Support for National dp8382[01] gigabit chips.
819 - NETWORK Support (other):
821 Support for the Calxeda XGMAC device
824 Support for SMSC's LAN91C96 chips.
826 CONFIG_LAN91C96_USE_32_BIT
827 Define this to enable 32 bit addressing
830 Support for SMSC's LAN91C111 chip
833 Define this to hold the physical address
834 of the device (I/O space)
836 CONFIG_SMC_USE_32_BIT
837 Define this if data bus is 32 bits
839 CONFIG_SMC_USE_IOFUNCS
840 Define this to use i/o functions instead of macros
841 (some hardware wont work with macros)
843 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
844 Define this if you have more then 3 PHYs.
847 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
849 CONFIG_FTGMAC100_EGIGA
850 Define this to use GE link update with gigabit PHY.
851 Define this if FTGMAC100 is connected to gigabit PHY.
852 If your system has 10/100 PHY only, it might not occur
853 wrong behavior. Because PHY usually return timeout or
854 useless data when polling gigabit status and gigabit
855 control registers. This behavior won't affect the
856 correctnessof 10/100 link speed update.
859 Support for Renesas on-chip Ethernet controller
861 CONFIG_SH_ETHER_USE_PORT
862 Define the number of ports to be used
864 CONFIG_SH_ETHER_PHY_ADDR
865 Define the ETH PHY's address
867 CONFIG_SH_ETHER_CACHE_WRITEBACK
868 If this option is set, the driver enables cache flush.
874 CONFIG_TPM_TIS_INFINEON
875 Support for Infineon i2c bus TPM devices. Only one device
876 per system is supported at this time.
878 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
879 Define the burst count bytes upper limit
882 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
884 CONFIG_TPM_ST33ZP24_I2C
885 Support for STMicroelectronics ST33ZP24 I2C devices.
886 Requires TPM_ST33ZP24 and I2C.
888 CONFIG_TPM_ST33ZP24_SPI
889 Support for STMicroelectronics ST33ZP24 SPI devices.
890 Requires TPM_ST33ZP24 and SPI.
893 Support for Atmel TWI TPM device. Requires I2C support.
896 Support for generic parallel port TPM devices. Only one device
897 per system is supported at this time.
899 CONFIG_TPM_TIS_BASE_ADDRESS
900 Base address where the generic TPM device is mapped
901 to. Contemporary x86 systems usually map it at
905 Define this to enable the TPM support library which provides
906 functional interfaces to some TPM commands.
907 Requires support for a TPM device.
909 CONFIG_TPM_AUTH_SESSIONS
910 Define this to enable authorized functions in the TPM library.
911 Requires CONFIG_TPM and CONFIG_SHA1.
914 At the moment only the UHCI host controller is
915 supported (PIP405, MIP405); define
916 CONFIG_USB_UHCI to enable it.
917 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
918 and define CONFIG_USB_STORAGE to enable the USB
921 Supported are USB Keyboards and USB Floppy drives
924 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
925 txfilltuning field in the EHCI controller on reset.
927 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
931 Define the below if you wish to use the USB console.
932 Once firmware is rebuilt from a serial console issue the
933 command "setenv stdin usbtty; setenv stdout usbtty" and
934 attach your USB cable. The Unix command "dmesg" should print
935 it has found a new device. The environment variable usbtty
936 can be set to gserial or cdc_acm to enable your device to
937 appear to a USB host as a Linux gserial device or a
938 Common Device Class Abstract Control Model serial device.
939 If you select usbtty = gserial you should be able to enumerate
941 # modprobe usbserial vendor=0xVendorID product=0xProductID
942 else if using cdc_acm, simply setting the environment
943 variable usbtty to be cdc_acm should suffice. The following
944 might be defined in YourBoardName.h
947 Define this to build a UDC device
950 Define this to have a tty type of device available to
951 talk to the UDC device
954 Define this to enable the high speed support for usb
955 device and usbtty. If this feature is enabled, a routine
956 int is_usbd_high_speed(void)
957 also needs to be defined by the driver to dynamically poll
958 whether the enumeration has succeded at high speed or full
961 If you have a USB-IF assigned VendorID then you may wish to
962 define your own vendor specific values either in BoardName.h
963 or directly in usbd_vendor_info.h. If you don't define
964 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
965 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
966 should pretend to be a Linux device to it's target host.
968 CONFIG_USBD_MANUFACTURER
969 Define this string as the name of your company for
970 - CONFIG_USBD_MANUFACTURER "my company"
972 CONFIG_USBD_PRODUCT_NAME
973 Define this string as the name of your product
974 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
977 Define this as your assigned Vendor ID from the USB
978 Implementors Forum. This *must* be a genuine Vendor ID
979 to avoid polluting the USB namespace.
980 - CONFIG_USBD_VENDORID 0xFFFF
982 CONFIG_USBD_PRODUCTID
983 Define this as the unique Product ID
985 - CONFIG_USBD_PRODUCTID 0xFFFF
987 - ULPI Layer Support:
988 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
989 the generic ULPI layer. The generic layer accesses the ULPI PHY
990 via the platform viewport, so you need both the genric layer and
991 the viewport enabled. Currently only Chipidea/ARC based
992 viewport is supported.
993 To enable the ULPI layer support, define CONFIG_USB_ULPI and
994 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
995 If your ULPI phy needs a different reference clock than the
996 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
997 the appropriate value in Hz.
1000 The MMC controller on the Intel PXA is supported. To
1001 enable this define CONFIG_MMC. The MMC can be
1002 accessed from the boot prompt by mapping the device
1003 to physical memory similar to flash. Command line is
1004 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1005 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1008 Support for Renesas on-chip MMCIF controller
1010 CONFIG_SH_MMCIF_ADDR
1011 Define the base address of MMCIF registers
1014 Define the clock frequency for MMCIF
1016 - USB Device Firmware Update (DFU) class support:
1018 This enables the USB portion of the DFU USB class
1021 This enables support for exposing NAND devices via DFU.
1024 This enables support for exposing RAM via DFU.
1025 Note: DFU spec refer to non-volatile memory usage, but
1026 allow usages beyond the scope of spec - here RAM usage,
1027 one that would help mostly the developer.
1029 CONFIG_SYS_DFU_DATA_BUF_SIZE
1030 Dfu transfer uses a buffer before writing data to the
1031 raw storage device. Make the size (in bytes) of this buffer
1032 configurable. The size of this buffer is also configurable
1033 through the "dfu_bufsiz" environment variable.
1035 CONFIG_SYS_DFU_MAX_FILE_SIZE
1036 When updating files rather than the raw storage device,
1037 we use a static buffer to copy the file into and then write
1038 the buffer once we've been given the whole file. Define
1039 this to the maximum filesize (in bytes) for the buffer.
1040 Default is 4 MiB if undefined.
1042 DFU_DEFAULT_POLL_TIMEOUT
1043 Poll timeout [ms], is the timeout a device can send to the
1044 host. The host must wait for this timeout before sending
1045 a subsequent DFU_GET_STATUS request to the device.
1047 DFU_MANIFEST_POLL_TIMEOUT
1048 Poll timeout [ms], which the device sends to the host when
1049 entering dfuMANIFEST state. Host waits this timeout, before
1050 sending again an USB request to the device.
1052 - Journaling Flash filesystem support:
1054 Define these for a default partition on a NAND device
1056 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1057 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1058 Define these for a default partition on a NOR device
1061 See Kconfig help for available keyboard drivers.
1065 Enable the Freescale DIU video driver. Reference boards for
1066 SOCs that have a DIU should define this macro to enable DIU
1067 support, and should also define these other macros:
1072 CONFIG_VIDEO_SW_CURSOR
1073 CONFIG_VGA_AS_SINGLE_DEVICE
1075 CONFIG_VIDEO_BMP_LOGO
1077 The DIU driver will look for the 'video-mode' environment
1078 variable, and if defined, enable the DIU as a console during
1079 boot. See the documentation file doc/README.video for a
1080 description of this variable.
1082 - LCD Support: CONFIG_LCD
1084 Define this to enable LCD support (for output to LCD
1085 display); also select one of the supported displays
1086 by defining one of these:
1090 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1092 CONFIG_NEC_NL6448AC33:
1094 NEC NL6448AC33-18. Active, color, single scan.
1096 CONFIG_NEC_NL6448BC20
1098 NEC NL6448BC20-08. 6.5", 640x480.
1099 Active, color, single scan.
1101 CONFIG_NEC_NL6448BC33_54
1103 NEC NL6448BC33-54. 10.4", 640x480.
1104 Active, color, single scan.
1108 Sharp 320x240. Active, color, single scan.
1109 It isn't 16x9, and I am not sure what it is.
1111 CONFIG_SHARP_LQ64D341
1113 Sharp LQ64D341 display, 640x480.
1114 Active, color, single scan.
1118 HLD1045 display, 640x480.
1119 Active, color, single scan.
1123 Optrex CBL50840-2 NF-FW 99 22 M5
1125 Hitachi LMG6912RPFC-00T
1129 320x240. Black & white.
1131 CONFIG_LCD_ALIGNMENT
1133 Normally the LCD is page-aligned (typically 4KB). If this is
1134 defined then the LCD will be aligned to this value instead.
1135 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1136 here, since it is cheaper to change data cache settings on
1137 a per-section basis.
1142 Sometimes, for example if the display is mounted in portrait
1143 mode or even if it's mounted landscape but rotated by 180degree,
1144 we need to rotate our content of the display relative to the
1145 framebuffer, so that user can read the messages which are
1147 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1148 initialized with a given rotation from "vl_rot" out of
1149 "vidinfo_t" which is provided by the board specific code.
1150 The value for vl_rot is coded as following (matching to
1151 fbcon=rotate:<n> linux-kernel commandline):
1152 0 = no rotation respectively 0 degree
1153 1 = 90 degree rotation
1154 2 = 180 degree rotation
1155 3 = 270 degree rotation
1157 If CONFIG_LCD_ROTATION is not defined, the console will be
1158 initialized with 0degree rotation.
1162 Support drawing of RLE8-compressed bitmaps on the LCD.
1165 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1167 The clock frequency of the MII bus
1169 CONFIG_PHY_RESET_DELAY
1171 Some PHY like Intel LXT971A need extra delay after
1172 reset before any MII register access is possible.
1173 For such PHY, set this option to the usec delay
1174 required. (minimum 300usec for LXT971A)
1176 CONFIG_PHY_CMD_DELAY (ppc4xx)
1178 Some PHY like Intel LXT971A need extra delay after
1179 command issued before MII status register can be read
1184 Define a default value for the IP address to use for
1185 the default Ethernet interface, in case this is not
1186 determined through e.g. bootp.
1187 (Environment variable "ipaddr")
1189 - Server IP address:
1192 Defines a default value for the IP address of a TFTP
1193 server to contact when using the "tftboot" command.
1194 (Environment variable "serverip")
1196 CONFIG_KEEP_SERVERADDR
1198 Keeps the server's MAC address, in the env 'serveraddr'
1199 for passing to bootargs (like Linux's netconsole option)
1201 - Gateway IP address:
1204 Defines a default value for the IP address of the
1205 default router where packets to other networks are
1207 (Environment variable "gatewayip")
1212 Defines a default value for the subnet mask (or
1213 routing prefix) which is used to determine if an IP
1214 address belongs to the local subnet or needs to be
1215 forwarded through a router.
1216 (Environment variable "netmask")
1218 - BOOTP Recovery Mode:
1219 CONFIG_BOOTP_RANDOM_DELAY
1221 If you have many targets in a network that try to
1222 boot using BOOTP, you may want to avoid that all
1223 systems send out BOOTP requests at precisely the same
1224 moment (which would happen for instance at recovery
1225 from a power failure, when all systems will try to
1226 boot, thus flooding the BOOTP server. Defining
1227 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1228 inserted before sending out BOOTP requests. The
1229 following delays are inserted then:
1231 1st BOOTP request: delay 0 ... 1 sec
1232 2nd BOOTP request: delay 0 ... 2 sec
1233 3rd BOOTP request: delay 0 ... 4 sec
1235 BOOTP requests: delay 0 ... 8 sec
1237 CONFIG_BOOTP_ID_CACHE_SIZE
1239 BOOTP packets are uniquely identified using a 32-bit ID. The
1240 server will copy the ID from client requests to responses and
1241 U-Boot will use this to determine if it is the destination of
1242 an incoming response. Some servers will check that addresses
1243 aren't in use before handing them out (usually using an ARP
1244 ping) and therefore take up to a few hundred milliseconds to
1245 respond. Network congestion may also influence the time it
1246 takes for a response to make it back to the client. If that
1247 time is too long, U-Boot will retransmit requests. In order
1248 to allow earlier responses to still be accepted after these
1249 retransmissions, U-Boot's BOOTP client keeps a small cache of
1250 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1251 cache. The default is to keep IDs for up to four outstanding
1252 requests. Increasing this will allow U-Boot to accept offers
1253 from a BOOTP client in networks with unusually high latency.
1255 - DHCP Advanced Options:
1256 You can fine tune the DHCP functionality by defining
1257 CONFIG_BOOTP_* symbols:
1259 CONFIG_BOOTP_NISDOMAIN
1260 CONFIG_BOOTP_BOOTFILESIZE
1261 CONFIG_BOOTP_NTPSERVER
1262 CONFIG_BOOTP_TIMEOFFSET
1263 CONFIG_BOOTP_VENDOREX
1264 CONFIG_BOOTP_MAY_FAIL
1266 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1267 environment variable, not the BOOTP server.
1269 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1270 after the configured retry count, the call will fail
1271 instead of starting over. This can be used to fail over
1272 to Link-local IP address configuration if the DHCP server
1275 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1277 A 32bit value in microseconds for a delay between
1278 receiving a "DHCP Offer" and sending the "DHCP Request".
1279 This fixes a problem with certain DHCP servers that don't
1280 respond 100% of the time to a "DHCP request". E.g. On an
1281 AT91RM9200 processor running at 180MHz, this delay needed
1282 to be *at least* 15,000 usec before a Windows Server 2003
1283 DHCP server would reply 100% of the time. I recommend at
1284 least 50,000 usec to be safe. The alternative is to hope
1285 that one of the retries will be successful but note that
1286 the DHCP timeout and retry process takes a longer than
1289 - Link-local IP address negotiation:
1290 Negotiate with other link-local clients on the local network
1291 for an address that doesn't require explicit configuration.
1292 This is especially useful if a DHCP server cannot be guaranteed
1293 to exist in all environments that the device must operate.
1295 See doc/README.link-local for more information.
1297 - MAC address from environment variables
1299 FDT_SEQ_MACADDR_FROM_ENV
1301 Fix-up device tree with MAC addresses fetched sequentially from
1302 environment variables. This config work on assumption that
1303 non-usable ethernet node of device-tree are either not present
1304 or their status has been marked as "disabled".
1307 CONFIG_CDP_DEVICE_ID
1309 The device id used in CDP trigger frames.
1311 CONFIG_CDP_DEVICE_ID_PREFIX
1313 A two character string which is prefixed to the MAC address
1318 A printf format string which contains the ascii name of
1319 the port. Normally is set to "eth%d" which sets
1320 eth0 for the first Ethernet, eth1 for the second etc.
1322 CONFIG_CDP_CAPABILITIES
1324 A 32bit integer which indicates the device capabilities;
1325 0x00000010 for a normal host which does not forwards.
1329 An ascii string containing the version of the software.
1333 An ascii string containing the name of the platform.
1337 A 32bit integer sent on the trigger.
1339 CONFIG_CDP_POWER_CONSUMPTION
1341 A 16bit integer containing the power consumption of the
1342 device in .1 of milliwatts.
1344 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1346 A byte containing the id of the VLAN.
1348 - Status LED: CONFIG_LED_STATUS
1350 Several configurations allow to display the current
1351 status using a LED. For instance, the LED will blink
1352 fast while running U-Boot code, stop blinking as
1353 soon as a reply to a BOOTP request was received, and
1354 start blinking slow once the Linux kernel is running
1355 (supported by a status LED driver in the Linux
1356 kernel). Defining CONFIG_LED_STATUS enables this
1361 CONFIG_LED_STATUS_GPIO
1362 The status LED can be connected to a GPIO pin.
1363 In such cases, the gpio_led driver can be used as a
1364 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1365 to include the gpio_led driver in the U-Boot binary.
1367 CONFIG_GPIO_LED_INVERTED_TABLE
1368 Some GPIO connected LEDs may have inverted polarity in which
1369 case the GPIO high value corresponds to LED off state and
1370 GPIO low value corresponds to LED on state.
1371 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
1372 with a list of GPIO LEDs that have inverted polarity.
1375 CONFIG_SYS_NUM_I2C_BUSES
1376 Hold the number of i2c buses you want to use.
1378 CONFIG_SYS_I2C_DIRECT_BUS
1379 define this, if you don't use i2c muxes on your hardware.
1380 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
1383 CONFIG_SYS_I2C_MAX_HOPS
1384 define how many muxes are maximal consecutively connected
1385 on one i2c bus. If you not use i2c muxes, omit this
1388 CONFIG_SYS_I2C_BUSES
1389 hold a list of buses you want to use, only used if
1390 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
1391 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
1392 CONFIG_SYS_NUM_I2C_BUSES = 9:
1394 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
1395 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
1396 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
1397 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
1398 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
1399 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
1400 {1, {I2C_NULL_HOP}}, \
1401 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
1402 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
1406 bus 0 on adapter 0 without a mux
1407 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
1408 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
1409 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
1410 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
1411 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
1412 bus 6 on adapter 1 without a mux
1413 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
1414 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
1416 If you do not have i2c muxes on your board, omit this define.
1418 - Legacy I2C Support:
1419 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
1420 then the following macros need to be defined (examples are
1421 from include/configs/lwmon.h):
1425 (Optional). Any commands necessary to enable the I2C
1426 controller or configure ports.
1428 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1432 The code necessary to make the I2C data line active
1433 (driven). If the data line is open collector, this
1436 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1440 The code necessary to make the I2C data line tri-stated
1441 (inactive). If the data line is open collector, this
1444 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1448 Code that returns true if the I2C data line is high,
1451 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1455 If <bit> is true, sets the I2C data line high. If it
1456 is false, it clears it (low).
1458 eg: #define I2C_SDA(bit) \
1459 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1460 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1464 If <bit> is true, sets the I2C clock line high. If it
1465 is false, it clears it (low).
1467 eg: #define I2C_SCL(bit) \
1468 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1469 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1473 This delay is invoked four times per clock cycle so this
1474 controls the rate of data transfer. The data rate thus
1475 is 1 / (I2C_DELAY * 4). Often defined to be something
1478 #define I2C_DELAY udelay(2)
1480 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1482 If your arch supports the generic GPIO framework (asm/gpio.h),
1483 then you may alternatively define the two GPIOs that are to be
1484 used as SCL / SDA. Any of the previous I2C_xxx macros will
1485 have GPIO-based defaults assigned to them as appropriate.
1487 You should define these to the GPIO value as given directly to
1488 the generic GPIO functions.
1490 CONFIG_SYS_I2C_INIT_BOARD
1492 When a board is reset during an i2c bus transfer
1493 chips might think that the current transfer is still
1494 in progress. On some boards it is possible to access
1495 the i2c SCLK line directly, either by using the
1496 processor pin as a GPIO or by having a second pin
1497 connected to the bus. If this option is defined a
1498 custom i2c_init_board() routine in boards/xxx/board.c
1499 is run early in the boot sequence.
1501 CONFIG_I2C_MULTI_BUS
1503 This option allows the use of multiple I2C buses, each of which
1504 must have a controller. At any point in time, only one bus is
1505 active. To switch to a different bus, use the 'i2c dev' command.
1506 Note that bus numbering is zero-based.
1508 CONFIG_SYS_I2C_NOPROBES
1510 This option specifies a list of I2C devices that will be skipped
1511 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1512 is set, specify a list of bus-device pairs. Otherwise, specify
1513 a 1D array of device addresses
1516 #undef CONFIG_I2C_MULTI_BUS
1517 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1519 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1521 #define CONFIG_I2C_MULTI_BUS
1522 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1524 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1526 CONFIG_SYS_SPD_BUS_NUM
1528 If defined, then this indicates the I2C bus number for DDR SPD.
1529 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1531 CONFIG_SYS_RTC_BUS_NUM
1533 If defined, then this indicates the I2C bus number for the RTC.
1534 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1536 CONFIG_SOFT_I2C_READ_REPEATED_START
1538 defining this will force the i2c_read() function in
1539 the soft_i2c driver to perform an I2C repeated start
1540 between writing the address pointer and reading the
1541 data. If this define is omitted the default behaviour
1542 of doing a stop-start sequence will be used. Most I2C
1543 devices can use either method, but some require one or
1546 - SPI Support: CONFIG_SPI
1548 Enables SPI driver (so far only tested with
1549 SPI EEPROM, also an instance works with Crystal A/D and
1550 D/As on the SACSng board)
1554 Enables a software (bit-bang) SPI driver rather than
1555 using hardware support. This is a general purpose
1556 driver that only requires three general I/O port pins
1557 (two outputs, one input) to function. If this is
1558 defined, the board configuration must define several
1559 SPI configuration items (port pins to use, etc). For
1560 an example, see include/configs/sacsng.h.
1562 CONFIG_SYS_SPI_MXC_WAIT
1563 Timeout for waiting until spi transfer completed.
1564 default: (CONFIG_SYS_HZ/100) /* 10 ms */
1566 - FPGA Support: CONFIG_FPGA
1568 Enables FPGA subsystem.
1570 CONFIG_FPGA_<vendor>
1572 Enables support for specific chip vendors.
1575 CONFIG_FPGA_<family>
1577 Enables support for FPGA family.
1578 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1582 Specify the number of FPGA devices to support.
1584 CONFIG_SYS_FPGA_PROG_FEEDBACK
1586 Enable printing of hash marks during FPGA configuration.
1588 CONFIG_SYS_FPGA_CHECK_BUSY
1590 Enable checks on FPGA configuration interface busy
1591 status by the configuration function. This option
1592 will require a board or device specific function to
1597 If defined, a function that provides delays in the FPGA
1598 configuration driver.
1600 CONFIG_SYS_FPGA_CHECK_CTRLC
1601 Allow Control-C to interrupt FPGA configuration
1603 CONFIG_SYS_FPGA_CHECK_ERROR
1605 Check for configuration errors during FPGA bitfile
1606 loading. For example, abort during Virtex II
1607 configuration if the INIT_B line goes low (which
1608 indicated a CRC error).
1610 CONFIG_SYS_FPGA_WAIT_INIT
1612 Maximum time to wait for the INIT_B line to de-assert
1613 after PROB_B has been de-asserted during a Virtex II
1614 FPGA configuration sequence. The default time is 500
1617 CONFIG_SYS_FPGA_WAIT_BUSY
1619 Maximum time to wait for BUSY to de-assert during
1620 Virtex II FPGA configuration. The default is 5 ms.
1622 CONFIG_SYS_FPGA_WAIT_CONFIG
1624 Time to wait after FPGA configuration. The default is
1627 - Configuration Management:
1631 If defined, this string will be added to the U-Boot
1632 version information (U_BOOT_VERSION)
1634 - Vendor Parameter Protection:
1636 U-Boot considers the values of the environment
1637 variables "serial#" (Board Serial Number) and
1638 "ethaddr" (Ethernet Address) to be parameters that
1639 are set once by the board vendor / manufacturer, and
1640 protects these variables from casual modification by
1641 the user. Once set, these variables are read-only,
1642 and write or delete attempts are rejected. You can
1643 change this behaviour:
1645 If CONFIG_ENV_OVERWRITE is #defined in your config
1646 file, the write protection for vendor parameters is
1647 completely disabled. Anybody can change or delete
1650 Alternatively, if you define _both_ an ethaddr in the
1651 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1652 Ethernet address is installed in the environment,
1653 which can be changed exactly ONCE by the user. [The
1654 serial# is unaffected by this, i. e. it remains
1657 The same can be accomplished in a more flexible way
1658 for any variable by configuring the type of access
1659 to allow for those variables in the ".flags" variable
1660 or define CONFIG_ENV_FLAGS_LIST_STATIC.
1665 Define this variable to enable the reservation of
1666 "protected RAM", i. e. RAM which is not overwritten
1667 by U-Boot. Define CONFIG_PRAM to hold the number of
1668 kB you want to reserve for pRAM. You can overwrite
1669 this default value by defining an environment
1670 variable "pram" to the number of kB you want to
1671 reserve. Note that the board info structure will
1672 still show the full amount of RAM. If pRAM is
1673 reserved, a new environment variable "mem" will
1674 automatically be defined to hold the amount of
1675 remaining RAM in a form that can be passed as boot
1676 argument to Linux, for instance like that:
1678 setenv bootargs ... mem=\${mem}
1681 This way you can tell Linux not to use this memory,
1682 either, which results in a memory region that will
1683 not be affected by reboots.
1685 *WARNING* If your board configuration uses automatic
1686 detection of the RAM size, you must make sure that
1687 this memory test is non-destructive. So far, the
1688 following board configurations are known to be
1691 IVMS8, IVML24, SPD8xx,
1692 HERMES, IP860, RPXlite, LWMON,
1695 - Access to physical memory region (> 4GB)
1696 Some basic support is provided for operations on memory not
1697 normally accessible to U-Boot - e.g. some architectures
1698 support access to more than 4GB of memory on 32-bit
1699 machines using physical address extension or similar.
1700 Define CONFIG_PHYSMEM to access this basic support, which
1701 currently only supports clearing the memory.
1704 CONFIG_NET_RETRY_COUNT
1706 This variable defines the number of retries for
1707 network operations like ARP, RARP, TFTP, or BOOTP
1708 before giving up the operation. If not defined, a
1709 default value of 5 is used.
1713 Timeout waiting for an ARP reply in milliseconds.
1717 Timeout in milliseconds used in NFS protocol.
1718 If you encounter "ERROR: Cannot umount" in nfs command,
1719 try longer timeout such as
1720 #define CONFIG_NFS_TIMEOUT 10000UL
1724 In the current implementation, the local variables
1725 space and global environment variables space are
1726 separated. Local variables are those you define by
1727 simply typing `name=value'. To access a local
1728 variable later on, you have write `$name' or
1729 `${name}'; to execute the contents of a variable
1730 directly type `$name' at the command prompt.
1732 Global environment variables are those you use
1733 setenv/printenv to work with. To run a command stored
1734 in such a variable, you need to use the run command,
1735 and you must not use the '$' sign to access them.
1737 To store commands and special characters in a
1738 variable, please use double quotation marks
1739 surrounding the whole text of the variable, instead
1740 of the backslashes before semicolons and special
1743 - Command Line Editing and History:
1744 CONFIG_CMDLINE_PS_SUPPORT
1746 Enable support for changing the command prompt string
1747 at run-time. Only static string is supported so far.
1748 The string is obtained from environment variables PS1
1751 - Default Environment:
1752 CONFIG_EXTRA_ENV_SETTINGS
1754 Define this to contain any number of null terminated
1755 strings (variable = value pairs) that will be part of
1756 the default environment compiled into the boot image.
1758 For example, place something like this in your
1759 board's config file:
1761 #define CONFIG_EXTRA_ENV_SETTINGS \
1765 Warning: This method is based on knowledge about the
1766 internal format how the environment is stored by the
1767 U-Boot code. This is NOT an official, exported
1768 interface! Although it is unlikely that this format
1769 will change soon, there is no guarantee either.
1770 You better know what you are doing here.
1772 Note: overly (ab)use of the default environment is
1773 discouraged. Make sure to check other ways to preset
1774 the environment like the "source" command or the
1777 CONFIG_DELAY_ENVIRONMENT
1779 Normally the environment is loaded when the board is
1780 initialised so that it is available to U-Boot. This inhibits
1781 that so that the environment is not available until
1782 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
1783 this is instead controlled by the value of
1784 /config/load-environment.
1786 - TFTP Fixed UDP Port:
1789 If this is defined, the environment variable tftpsrcp
1790 is used to supply the TFTP UDP source port value.
1791 If tftpsrcp isn't defined, the normal pseudo-random port
1792 number generator is used.
1794 Also, the environment variable tftpdstp is used to supply
1795 the TFTP UDP destination port value. If tftpdstp isn't
1796 defined, the normal port 69 is used.
1798 The purpose for tftpsrcp is to allow a TFTP server to
1799 blindly start the TFTP transfer using the pre-configured
1800 target IP address and UDP port. This has the effect of
1801 "punching through" the (Windows XP) firewall, allowing
1802 the remainder of the TFTP transfer to proceed normally.
1803 A better solution is to properly configure the firewall,
1804 but sometimes that is not allowed.
1806 CONFIG_STANDALONE_LOAD_ADDR
1808 This option defines a board specific value for the
1809 address where standalone program gets loaded, thus
1810 overwriting the architecture dependent default
1813 - Frame Buffer Address:
1816 Define CONFIG_FB_ADDR if you want to use specific
1817 address for frame buffer. This is typically the case
1818 when using a graphics controller has separate video
1819 memory. U-Boot will then place the frame buffer at
1820 the given address instead of dynamically reserving it
1821 in system RAM by calling lcd_setmem(), which grabs
1822 the memory for the frame buffer depending on the
1823 configured panel size.
1825 Please see board_init_f function.
1827 - Automatic software updates via TFTP server
1829 CONFIG_UPDATE_TFTP_CNT_MAX
1830 CONFIG_UPDATE_TFTP_MSEC_MAX
1832 These options enable and control the auto-update feature;
1833 for a more detailed description refer to doc/README.update.
1835 - MTD Support (mtdparts command, UBI support)
1836 CONFIG_MTD_UBI_WL_THRESHOLD
1837 This parameter defines the maximum difference between the highest
1838 erase counter value and the lowest erase counter value of eraseblocks
1839 of UBI devices. When this threshold is exceeded, UBI starts performing
1840 wear leveling by means of moving data from eraseblock with low erase
1841 counter to eraseblocks with high erase counter.
1843 The default value should be OK for SLC NAND flashes, NOR flashes and
1844 other flashes which have eraseblock life-cycle 100000 or more.
1845 However, in case of MLC NAND flashes which typically have eraseblock
1846 life-cycle less than 10000, the threshold should be lessened (e.g.,
1847 to 128 or 256, although it does not have to be power of 2).
1851 CONFIG_MTD_UBI_BEB_LIMIT
1852 This option specifies the maximum bad physical eraseblocks UBI
1853 expects on the MTD device (per 1024 eraseblocks). If the
1854 underlying flash does not admit of bad eraseblocks (e.g. NOR
1855 flash), this value is ignored.
1857 NAND datasheets often specify the minimum and maximum NVM
1858 (Number of Valid Blocks) for the flashes' endurance lifetime.
1859 The maximum expected bad eraseblocks per 1024 eraseblocks
1860 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
1861 which gives 20 for most NANDs (MaxNVB is basically the total
1862 count of eraseblocks on the chip).
1864 To put it differently, if this value is 20, UBI will try to
1865 reserve about 1.9% of physical eraseblocks for bad blocks
1866 handling. And that will be 1.9% of eraseblocks on the entire
1867 NAND chip, not just the MTD partition UBI attaches. This means
1868 that if you have, say, a NAND flash chip admits maximum 40 bad
1869 eraseblocks, and it is split on two MTD partitions of the same
1870 size, UBI will reserve 40 eraseblocks when attaching a
1875 CONFIG_MTD_UBI_FASTMAP
1876 Fastmap is a mechanism which allows attaching an UBI device
1877 in nearly constant time. Instead of scanning the whole MTD device it
1878 only has to locate a checkpoint (called fastmap) on the device.
1879 The on-flash fastmap contains all information needed to attach
1880 the device. Using fastmap makes only sense on large devices where
1881 attaching by scanning takes long. UBI will not automatically install
1882 a fastmap on old images, but you can set the UBI parameter
1883 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
1884 that fastmap-enabled images are still usable with UBI implementations
1885 without fastmap support. On typical flash devices the whole fastmap
1886 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
1888 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
1889 Set this parameter to enable fastmap automatically on images
1893 CONFIG_MTD_UBI_FM_DEBUG
1894 Enable UBI fastmap debug
1899 Enable building of SPL globally.
1901 CONFIG_SPL_MAX_FOOTPRINT
1902 Maximum size in memory allocated to the SPL, BSS included.
1903 When defined, the linker checks that the actual memory
1904 used by SPL from _start to __bss_end does not exceed it.
1905 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
1906 must not be both defined at the same time.
1909 Maximum size of the SPL image (text, data, rodata, and
1910 linker lists sections), BSS excluded.
1911 When defined, the linker checks that the actual size does
1914 CONFIG_SPL_RELOC_TEXT_BASE
1915 Address to relocate to. If unspecified, this is equal to
1916 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
1918 CONFIG_SPL_BSS_START_ADDR
1919 Link address for the BSS within the SPL binary.
1921 CONFIG_SPL_BSS_MAX_SIZE
1922 Maximum size in memory allocated to the SPL BSS.
1923 When defined, the linker checks that the actual memory used
1924 by SPL from __bss_start to __bss_end does not exceed it.
1925 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
1926 must not be both defined at the same time.
1929 Adress of the start of the stack SPL will use
1931 CONFIG_SPL_PANIC_ON_RAW_IMAGE
1932 When defined, SPL will panic() if the image it has
1933 loaded does not have a signature.
1934 Defining this is useful when code which loads images
1935 in SPL cannot guarantee that absolutely all read errors
1937 An example is the LPC32XX MLC NAND driver, which will
1938 consider that a completely unreadable NAND block is bad,
1939 and thus should be skipped silently.
1941 CONFIG_SPL_RELOC_STACK
1942 Adress of the start of the stack SPL will use after
1943 relocation. If unspecified, this is equal to
1946 CONFIG_SYS_SPL_MALLOC_START
1947 Starting address of the malloc pool used in SPL.
1948 When this option is set the full malloc is used in SPL and
1949 it is set up by spl_init() and before that, the simple malloc()
1950 can be used if CONFIG_SYS_MALLOC_F is defined.
1952 CONFIG_SYS_SPL_MALLOC_SIZE
1953 The size of the malloc pool used in SPL.
1955 CONFIG_SPL_DISPLAY_PRINT
1956 For ARM, enable an optional function to print more information
1957 about the running system.
1959 CONFIG_SPL_INIT_MINIMAL
1960 Arch init code should be built for a very small image
1962 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
1963 Partition on the MMC to load U-Boot from when the MMC is being
1966 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
1967 Sector to load kernel uImage from when MMC is being
1968 used in raw mode (for Falcon mode)
1970 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
1971 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
1972 Sector and number of sectors to load kernel argument
1973 parameters from when MMC is being used in raw mode
1976 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
1977 Filename to read to load U-Boot when reading from filesystem
1979 CONFIG_SPL_FS_LOAD_KERNEL_NAME
1980 Filename to read to load kernel uImage when reading
1981 from filesystem (for Falcon mode)
1983 CONFIG_SPL_FS_LOAD_ARGS_NAME
1984 Filename to read to load kernel argument parameters
1985 when reading from filesystem (for Falcon mode)
1987 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
1988 Set this for NAND SPL on PPC mpc83xx targets, so that
1989 start.S waits for the rest of the SPL to load before
1990 continuing (the hardware starts execution after just
1991 loading the first page rather than the full 4K).
1993 CONFIG_SPL_SKIP_RELOCATE
1994 Avoid SPL relocation
1996 CONFIG_SPL_NAND_IDENT
1997 SPL uses the chip ID list to identify the NAND flash.
1998 Requires CONFIG_SPL_NAND_BASE.
2001 Support for a lightweight UBI (fastmap) scanner and
2004 CONFIG_SPL_NAND_RAW_ONLY
2005 Support to boot only raw u-boot.bin images. Use this only
2006 if you need to save space.
2008 CONFIG_SPL_COMMON_INIT_DDR
2009 Set for common ddr init with serial presence detect in
2012 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2013 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2014 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2015 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2016 CONFIG_SYS_NAND_ECCBYTES
2017 Defines the size and behavior of the NAND that SPL uses
2020 CONFIG_SYS_NAND_U_BOOT_DST
2021 Location in memory to load U-Boot to
2023 CONFIG_SYS_NAND_U_BOOT_SIZE
2024 Size of image to load
2026 CONFIG_SYS_NAND_U_BOOT_START
2027 Entry point in loaded image to jump to
2029 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2030 Define this if you need to first read the OOB and then the
2031 data. This is used, for example, on davinci platforms.
2033 CONFIG_SPL_RAM_DEVICE
2034 Support for running image already present in ram, in SPL binary
2037 Image offset to which the SPL should be padded before appending
2038 the SPL payload. By default, this is defined as
2039 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
2040 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
2041 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
2044 Final target image containing SPL and payload. Some SPLs
2045 use an arch-specific makefile fragment instead, for
2046 example if more than one image needs to be produced.
2048 CONFIG_SPL_FIT_PRINT
2049 Printing information about a FIT image adds quite a bit of
2050 code to SPL. So this is normally disabled in SPL. Use this
2051 option to re-enable it. This will affect the output of the
2052 bootm command when booting a FIT image.
2056 Enable building of TPL globally.
2059 Image offset to which the TPL should be padded before appending
2060 the TPL payload. By default, this is defined as
2061 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
2062 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
2063 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
2065 - Interrupt support (PPC):
2067 There are common interrupt_init() and timer_interrupt()
2068 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2069 for CPU specific initialization. interrupt_init_cpu()
2070 should set decrementer_count to appropriate value. If
2071 CPU resets decrementer automatically after interrupt
2072 (ppc4xx) it should set decrementer_count to zero.
2073 timer_interrupt() calls timer_interrupt_cpu() for CPU
2074 specific handling. If board has watchdog / status_led
2075 / other_activity_monitor it works automatically from
2076 general timer_interrupt().
2079 Board initialization settings:
2080 ------------------------------
2082 During Initialization u-boot calls a number of board specific functions
2083 to allow the preparation of board specific prerequisites, e.g. pin setup
2084 before drivers are initialized. To enable these callbacks the
2085 following configuration macros have to be defined. Currently this is
2086 architecture specific, so please check arch/your_architecture/lib/board.c
2087 typically in board_init_f() and board_init_r().
2089 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2090 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2091 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2092 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2094 Configuration Settings:
2095 -----------------------
2097 - MEM_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
2098 Optionally it can be defined to support 64-bit memory commands.
2100 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2101 undefine this when you're short of memory.
2103 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2104 width of the commands listed in the 'help' command output.
2106 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2107 prompt for user input.
2109 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2111 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2113 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2115 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2116 the application (usually a Linux kernel) when it is
2119 - CONFIG_SYS_BAUDRATE_TABLE:
2120 List of legal baudrate settings for this board.
2122 - CONFIG_SYS_MEM_RESERVE_SECURE
2123 Only implemented for ARMv8 for now.
2124 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
2125 is substracted from total RAM and won't be reported to OS.
2126 This memory can be used as secure memory. A variable
2127 gd->arch.secure_ram is used to track the location. In systems
2128 the RAM base is not zero, or RAM is divided into banks,
2129 this variable needs to be recalcuated to get the address.
2131 - CONFIG_SYS_MEM_TOP_HIDE:
2132 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2133 this specified memory area will get subtracted from the top
2134 (end) of RAM and won't get "touched" at all by U-Boot. By
2135 fixing up gd->ram_size the Linux kernel should gets passed
2136 the now "corrected" memory size and won't touch it either.
2137 This should work for arch/ppc and arch/powerpc. Only Linux
2138 board ports in arch/powerpc with bootwrapper support that
2139 recalculate the memory size from the SDRAM controller setup
2140 will have to get fixed in Linux additionally.
2142 This option can be used as a workaround for the 440EPx/GRx
2143 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2146 WARNING: Please make sure that this value is a multiple of
2147 the Linux page size (normally 4k). If this is not the case,
2148 then the end address of the Linux memory will be located at a
2149 non page size aligned address and this could cause major
2152 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2153 Enable temporary baudrate change while serial download
2155 - CONFIG_SYS_SDRAM_BASE:
2156 Physical start address of SDRAM. _Must_ be 0 here.
2158 - CONFIG_SYS_FLASH_BASE:
2159 Physical start address of Flash memory.
2161 - CONFIG_SYS_MONITOR_BASE:
2162 Physical start address of boot monitor code (set by
2163 make config files to be same as the text base address
2164 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2165 CONFIG_SYS_FLASH_BASE when booting from flash.
2167 - CONFIG_SYS_MONITOR_LEN:
2168 Size of memory reserved for monitor code, used to
2169 determine _at_compile_time_ (!) if the environment is
2170 embedded within the U-Boot image, or in a separate
2173 - CONFIG_SYS_MALLOC_LEN:
2174 Size of DRAM reserved for malloc() use.
2176 - CONFIG_SYS_MALLOC_F_LEN
2177 Size of the malloc() pool for use before relocation. If
2178 this is defined, then a very simple malloc() implementation
2179 will become available before relocation. The address is just
2180 below the global data, and the stack is moved down to make
2183 This feature allocates regions with increasing addresses
2184 within the region. calloc() is supported, but realloc()
2185 is not available. free() is supported but does nothing.
2186 The memory will be freed (or in fact just forgotten) when
2187 U-Boot relocates itself.
2189 - CONFIG_SYS_MALLOC_SIMPLE
2190 Provides a simple and small malloc() and calloc() for those
2191 boards which do not use the full malloc in SPL (which is
2192 enabled with CONFIG_SYS_SPL_MALLOC_START).
2194 - CONFIG_SYS_NONCACHED_MEMORY:
2195 Size of non-cached memory area. This area of memory will be
2196 typically located right below the malloc() area and mapped
2197 uncached in the MMU. This is useful for drivers that would
2198 otherwise require a lot of explicit cache maintenance. For
2199 some drivers it's also impossible to properly maintain the
2200 cache. For example if the regions that need to be flushed
2201 are not a multiple of the cache-line size, *and* padding
2202 cannot be allocated between the regions to align them (i.e.
2203 if the HW requires a contiguous array of regions, and the
2204 size of each region is not cache-aligned), then a flush of
2205 one region may result in overwriting data that hardware has
2206 written to another region in the same cache-line. This can
2207 happen for example in network drivers where descriptors for
2208 buffers are typically smaller than the CPU cache-line (e.g.
2209 16 bytes vs. 32 or 64 bytes).
2211 Non-cached memory is only supported on 32-bit ARM at present.
2213 - CONFIG_SYS_BOOTM_LEN:
2214 Normally compressed uImages are limited to an
2215 uncompressed size of 8 MBytes. If this is not enough,
2216 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2217 to adjust this setting to your needs.
2219 - CONFIG_SYS_BOOTMAPSZ:
2220 Maximum size of memory mapped by the startup code of
2221 the Linux kernel; all data that must be processed by
2222 the Linux kernel (bd_info, boot arguments, FDT blob if
2223 used) must be put below this limit, unless "bootm_low"
2224 environment variable is defined and non-zero. In such case
2225 all data for the Linux kernel must be between "bootm_low"
2226 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2227 variable "bootm_mapsize" will override the value of
2228 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2229 then the value in "bootm_size" will be used instead.
2231 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2232 Enable initrd_high functionality. If defined then the
2233 initrd_high feature is enabled and the bootm ramdisk subcommand
2236 - CONFIG_SYS_BOOT_GET_CMDLINE:
2237 Enables allocating and saving kernel cmdline in space between
2238 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2240 - CONFIG_SYS_BOOT_GET_KBD:
2241 Enables allocating and saving a kernel copy of the bd_info in
2242 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2244 - CONFIG_SYS_MAX_FLASH_BANKS:
2245 Max number of Flash memory banks
2247 - CONFIG_SYS_MAX_FLASH_SECT:
2248 Max number of sectors on a Flash chip
2250 - CONFIG_SYS_FLASH_ERASE_TOUT:
2251 Timeout for Flash erase operations (in ms)
2253 - CONFIG_SYS_FLASH_WRITE_TOUT:
2254 Timeout for Flash write operations (in ms)
2256 - CONFIG_SYS_FLASH_LOCK_TOUT
2257 Timeout for Flash set sector lock bit operation (in ms)
2259 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2260 Timeout for Flash clear lock bits operation (in ms)
2262 - CONFIG_SYS_FLASH_PROTECTION
2263 If defined, hardware flash sectors protection is used
2264 instead of U-Boot software protection.
2266 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2268 Enable TFTP transfers directly to flash memory;
2269 without this option such a download has to be
2270 performed in two steps: (1) download to RAM, and (2)
2271 copy from RAM to flash.
2273 The two-step approach is usually more reliable, since
2274 you can check if the download worked before you erase
2275 the flash, but in some situations (when system RAM is
2276 too limited to allow for a temporary copy of the
2277 downloaded image) this option may be very useful.
2279 - CONFIG_SYS_FLASH_CFI:
2280 Define if the flash driver uses extra elements in the
2281 common flash structure for storing flash geometry.
2283 - CONFIG_FLASH_CFI_DRIVER
2284 This option also enables the building of the cfi_flash driver
2285 in the drivers directory
2287 - CONFIG_FLASH_CFI_MTD
2288 This option enables the building of the cfi_mtd driver
2289 in the drivers directory. The driver exports CFI flash
2292 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2293 Use buffered writes to flash.
2295 - CONFIG_FLASH_SPANSION_S29WS_N
2296 s29ws-n MirrorBit flash has non-standard addresses for buffered
2299 - CONFIG_SYS_FLASH_QUIET_TEST
2300 If this option is defined, the common CFI flash doesn't
2301 print it's warning upon not recognized FLASH banks. This
2302 is useful, if some of the configured banks are only
2303 optionally available.
2305 - CONFIG_FLASH_SHOW_PROGRESS
2306 If defined (must be an integer), print out countdown
2307 digits and dots. Recommended value: 45 (9..1) for 80
2308 column displays, 15 (3..1) for 40 column displays.
2310 - CONFIG_FLASH_VERIFY
2311 If defined, the content of the flash (destination) is compared
2312 against the source after the write operation. An error message
2313 will be printed when the contents are not identical.
2314 Please note that this option is useless in nearly all cases,
2315 since such flash programming errors usually are detected earlier
2316 while unprotecting/erasing/programming. Please only enable
2317 this option if you really know what you are doing.
2319 - CONFIG_SYS_RX_ETH_BUFFER:
2320 Defines the number of Ethernet receive buffers. On some
2321 Ethernet controllers it is recommended to set this value
2322 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2323 buffers can be full shortly after enabling the interface
2324 on high Ethernet traffic.
2325 Defaults to 4 if not defined.
2327 - CONFIG_ENV_MAX_ENTRIES
2329 Maximum number of entries in the hash table that is used
2330 internally to store the environment settings. The default
2331 setting is supposed to be generous and should work in most
2332 cases. This setting can be used to tune behaviour; see
2333 lib/hashtable.c for details.
2335 - CONFIG_ENV_FLAGS_LIST_DEFAULT
2336 - CONFIG_ENV_FLAGS_LIST_STATIC
2337 Enable validation of the values given to environment variables when
2338 calling env set. Variables can be restricted to only decimal,
2339 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
2340 the variables can also be restricted to IP address or MAC address.
2342 The format of the list is:
2343 type_attribute = [s|d|x|b|i|m]
2344 access_attribute = [a|r|o|c]
2345 attributes = type_attribute[access_attribute]
2346 entry = variable_name[:attributes]
2349 The type attributes are:
2350 s - String (default)
2353 b - Boolean ([1yYtT|0nNfF])
2357 The access attributes are:
2363 - CONFIG_ENV_FLAGS_LIST_DEFAULT
2364 Define this to a list (string) to define the ".flags"
2365 environment variable in the default or embedded environment.
2367 - CONFIG_ENV_FLAGS_LIST_STATIC
2368 Define this to a list (string) to define validation that
2369 should be done if an entry is not found in the ".flags"
2370 environment variable. To override a setting in the static
2371 list, simply add an entry for the same variable name to the
2374 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
2375 regular expression. This allows multiple variables to define the same
2376 flags without explicitly listing them for each variable.
2378 The following definitions that deal with the placement and management
2379 of environment data (variable area); in general, we support the
2380 following configurations:
2382 - CONFIG_BUILD_ENVCRC:
2384 Builds up envcrc with the target environment so that external utils
2385 may easily extract it and embed it in final U-Boot images.
2387 BE CAREFUL! The first access to the environment happens quite early
2388 in U-Boot initialization (when we try to get the setting of for the
2389 console baudrate). You *MUST* have mapped your NVRAM area then, or
2392 Please note that even with NVRAM we still use a copy of the
2393 environment in RAM: we could work on NVRAM directly, but we want to
2394 keep settings there always unmodified except somebody uses "saveenv"
2395 to save the current settings.
2397 BE CAREFUL! For some special cases, the local device can not use
2398 "saveenv" command. For example, the local device will get the
2399 environment stored in a remote NOR flash by SRIO or PCIE link,
2400 but it can not erase, write this NOR flash by SRIO or PCIE interface.
2402 - CONFIG_NAND_ENV_DST
2404 Defines address in RAM to which the nand_spl code should copy the
2405 environment. If redundant environment is used, it will be copied to
2406 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
2408 Please note that the environment is read-only until the monitor
2409 has been relocated to RAM and a RAM copy of the environment has been
2410 created; also, when using EEPROM you will have to use env_get_f()
2411 until then to read environment variables.
2413 The environment is protected by a CRC32 checksum. Before the monitor
2414 is relocated into RAM, as a result of a bad CRC you will be working
2415 with the compiled-in default environment - *silently*!!! [This is
2416 necessary, because the first environment variable we need is the
2417 "baudrate" setting for the console - if we have a bad CRC, we don't
2418 have any device yet where we could complain.]
2420 Note: once the monitor has been relocated, then it will complain if
2421 the default environment is used; a new CRC is computed as soon as you
2422 use the "saveenv" command to store a valid environment.
2424 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
2425 Echo the inverted Ethernet link state to the fault LED.
2427 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
2428 also needs to be defined.
2430 - CONFIG_SYS_FAULT_MII_ADDR:
2431 MII address of the PHY to check for the Ethernet link state.
2433 - CONFIG_NS16550_MIN_FUNCTIONS:
2434 Define this if you desire to only have use of the NS16550_init
2435 and NS16550_putc functions for the serial driver located at
2436 drivers/serial/ns16550.c. This option is useful for saving
2437 space for already greatly restricted images, including but not
2438 limited to NAND_SPL configurations.
2440 - CONFIG_DISPLAY_BOARDINFO
2441 Display information about the board that U-Boot is running on
2442 when U-Boot starts up. The board function checkboard() is called
2445 - CONFIG_DISPLAY_BOARDINFO_LATE
2446 Similar to the previous option, but display this information
2447 later, once stdio is running and output goes to the LCD, if
2450 - CONFIG_BOARD_SIZE_LIMIT:
2451 Maximum size of the U-Boot image. When defined, the
2452 build system checks that the actual size does not
2455 Low Level (hardware related) configuration options:
2456 ---------------------------------------------------
2458 - CONFIG_SYS_CACHELINE_SIZE:
2459 Cache Line Size of the CPU.
2461 - CONFIG_SYS_CCSRBAR_DEFAULT:
2462 Default (power-on reset) physical address of CCSR on Freescale
2465 - CONFIG_SYS_CCSRBAR:
2466 Virtual address of CCSR. On a 32-bit build, this is typically
2467 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
2469 - CONFIG_SYS_CCSRBAR_PHYS:
2470 Physical address of CCSR. CCSR can be relocated to a new
2471 physical address, if desired. In this case, this macro should
2472 be set to that address. Otherwise, it should be set to the
2473 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
2474 is typically relocated on 36-bit builds. It is recommended
2475 that this macro be defined via the _HIGH and _LOW macros:
2477 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
2478 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
2480 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
2481 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
2482 either 0 (32-bit build) or 0xF (36-bit build). This macro is
2483 used in assembly code, so it must not contain typecasts or
2484 integer size suffixes (e.g. "ULL").
2486 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
2487 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
2488 used in assembly code, so it must not contain typecasts or
2489 integer size suffixes (e.g. "ULL").
2491 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
2492 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
2493 forced to a value that ensures that CCSR is not relocated.
2496 Most IDE controllers were designed to be connected with PCI
2497 interface. Only few of them were designed for AHB interface.
2498 When software is doing ATA command and data transfer to
2499 IDE devices through IDE-AHB controller, some additional
2500 registers accessing to these kind of IDE-AHB controller
2503 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
2504 DO NOT CHANGE unless you know exactly what you're
2505 doing! (11-4) [MPC8xx systems only]
2507 - CONFIG_SYS_INIT_RAM_ADDR:
2509 Start address of memory area that can be used for
2510 initial data and stack; please note that this must be
2511 writable memory that is working WITHOUT special
2512 initialization, i. e. you CANNOT use normal RAM which
2513 will become available only after programming the
2514 memory controller and running certain initialization
2517 U-Boot uses the following memory types:
2518 - MPC8xx: IMMR (internal memory of the CPU)
2520 - CONFIG_SYS_GBL_DATA_OFFSET:
2522 Offset of the initial data structure in the memory
2523 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
2524 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
2525 data is located at the end of the available space
2526 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
2527 GENERATED_GBL_DATA_SIZE), and the initial stack is just
2528 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
2529 CONFIG_SYS_GBL_DATA_OFFSET) downward.
2532 On the MPC824X (or other systems that use the data
2533 cache for initial memory) the address chosen for
2534 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
2535 point to an otherwise UNUSED address space between
2536 the top of RAM and the start of the PCI space.
2538 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
2540 - CONFIG_SYS_OR_TIMING_SDRAM:
2543 - CONFIG_SYS_MAMR_PTA:
2544 periodic timer for refresh
2547 Chip has SRIO or not
2550 Board has SRIO 1 port available
2553 Board has SRIO 2 port available
2555 - CONFIG_SRIO_PCIE_BOOT_MASTER
2556 Board can support master function for Boot from SRIO and PCIE
2558 - CONFIG_SYS_SRIOn_MEM_VIRT:
2559 Virtual Address of SRIO port 'n' memory region
2561 - CONFIG_SYS_SRIOn_MEM_PHYxS:
2562 Physical Address of SRIO port 'n' memory region
2564 - CONFIG_SYS_SRIOn_MEM_SIZE:
2565 Size of SRIO port 'n' memory region
2567 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
2568 Defined to tell the NAND controller that the NAND chip is using
2570 Not all NAND drivers use this symbol.
2571 Example of drivers that use it:
2572 - drivers/mtd/nand/raw/ndfc.c
2573 - drivers/mtd/nand/raw/mxc_nand.c
2575 - CONFIG_SYS_NDFC_EBC0_CFG
2576 Sets the EBC0_CFG register for the NDFC. If not defined
2577 a default value will be used.
2580 Get DDR timing information from an I2C EEPROM. Common
2581 with pluggable memory modules such as SODIMMs
2584 I2C address of the SPD EEPROM
2586 - CONFIG_SYS_SPD_BUS_NUM
2587 If SPD EEPROM is on an I2C bus other than the first
2588 one, specify here. Note that the value must resolve
2589 to something your driver can deal with.
2591 - CONFIG_SYS_DDR_RAW_TIMING
2592 Get DDR timing information from other than SPD. Common with
2593 soldered DDR chips onboard without SPD. DDR raw timing
2594 parameters are extracted from datasheet and hard-coded into
2595 header files or board specific files.
2597 - CONFIG_FSL_DDR_INTERACTIVE
2598 Enable interactive DDR debugging. See doc/README.fsl-ddr.
2600 - CONFIG_FSL_DDR_SYNC_REFRESH
2601 Enable sync of refresh for multiple controllers.
2603 - CONFIG_FSL_DDR_BIST
2604 Enable built-in memory test for Freescale DDR controllers.
2606 - CONFIG_SYS_83XX_DDR_USES_CS0
2607 Only for 83xx systems. If specified, then DDR should
2608 be configured using CS0 and CS1 instead of CS2 and CS3.
2611 Enable RMII mode for all FECs.
2612 Note that this is a global option, we can't
2613 have one FEC in standard MII mode and another in RMII mode.
2615 - CONFIG_CRC32_VERIFY
2616 Add a verify option to the crc32 command.
2619 => crc32 -v <address> <count> <crc32>
2621 Where address/count indicate a memory area
2622 and crc32 is the correct crc32 which the
2626 Add the "loopw" memory command. This only takes effect if
2627 the memory commands are activated globally (CONFIG_CMD_MEMORY).
2629 - CONFIG_CMD_MX_CYCLIC
2630 Add the "mdc" and "mwc" memory commands. These are cyclic
2635 This command will print 4 bytes (10,11,12,13) each 500 ms.
2637 => mwc.l 100 12345678 10
2638 This command will write 12345678 to address 100 all 10 ms.
2640 This only takes effect if the memory commands are activated
2641 globally (CONFIG_CMD_MEMORY).
2644 Set when the currently-running compilation is for an artifact
2645 that will end up in the SPL (as opposed to the TPL or U-Boot
2646 proper). Code that needs stage-specific behavior should check
2650 Set when the currently-running compilation is for an artifact
2651 that will end up in the TPL (as opposed to the SPL or U-Boot
2652 proper). Code that needs stage-specific behavior should check
2655 - CONFIG_SYS_MPC85XX_NO_RESETVEC
2656 Only for 85xx systems. If this variable is specified, the section
2657 .resetvec is not kept and the section .bootpg is placed in the
2658 previous 4k of the .text section.
2660 - CONFIG_ARCH_MAP_SYSMEM
2661 Generally U-Boot (and in particular the md command) uses
2662 effective address. It is therefore not necessary to regard
2663 U-Boot address as virtual addresses that need to be translated
2664 to physical addresses. However, sandbox requires this, since
2665 it maintains its own little RAM buffer which contains all
2666 addressable memory. This option causes some memory accesses
2667 to be mapped through map_sysmem() / unmap_sysmem().
2669 - CONFIG_X86_RESET_VECTOR
2670 If defined, the x86 reset vector code is included. This is not
2671 needed when U-Boot is running from Coreboot.
2673 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
2674 Option to disable subpage write in NAND driver
2675 driver that uses this:
2676 drivers/mtd/nand/raw/davinci_nand.c
2678 Freescale QE/FMAN Firmware Support:
2679 -----------------------------------
2681 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
2682 loading of "firmware", which is encoded in the QE firmware binary format.
2683 This firmware often needs to be loaded during U-Boot booting, so macros
2684 are used to identify the storage device (NOR flash, SPI, etc) and the address
2687 - CONFIG_SYS_FMAN_FW_ADDR
2688 The address in the storage device where the FMAN microcode is located. The
2689 meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro
2692 - CONFIG_SYS_QE_FW_ADDR
2693 The address in the storage device where the QE microcode is located. The
2694 meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro
2697 - CONFIG_SYS_QE_FMAN_FW_LENGTH
2698 The maximum possible size of the firmware. The firmware binary format
2699 has a field that specifies the actual size of the firmware, but it
2700 might not be possible to read any part of the firmware unless some
2701 local storage is allocated to hold the entire firmware first.
2703 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
2704 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
2705 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
2706 virtual address in NOR flash.
2708 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
2709 Specifies that QE/FMAN firmware is located in NAND flash.
2710 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
2712 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
2713 Specifies that QE/FMAN firmware is located on the primary SD/MMC
2714 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
2716 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
2717 Specifies that QE/FMAN firmware is located in the remote (master)
2718 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
2719 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
2720 window->master inbound window->master LAW->the ucode address in
2721 master's memory space.
2723 Freescale Layerscape Management Complex Firmware Support:
2724 ---------------------------------------------------------
2725 The Freescale Layerscape Management Complex (MC) supports the loading of
2727 This firmware often needs to be loaded during U-Boot booting, so macros
2728 are used to identify the storage device (NOR flash, SPI, etc) and the address
2731 - CONFIG_FSL_MC_ENET
2732 Enable the MC driver for Layerscape SoCs.
2734 Freescale Layerscape Debug Server Support:
2735 -------------------------------------------
2736 The Freescale Layerscape Debug Server Support supports the loading of
2737 "Debug Server firmware" and triggering SP boot-rom.
2738 This firmware often needs to be loaded during U-Boot booting.
2740 - CONFIG_SYS_MC_RSV_MEM_ALIGN
2741 Define alignment of reserved memory MC requires
2746 In order to achieve reproducible builds, timestamps used in the U-Boot build
2747 process have to be set to a fixed value.
2749 This is done using the SOURCE_DATE_EPOCH environment variable.
2750 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
2751 option for U-Boot or an environment variable in U-Boot.
2753 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
2755 Building the Software:
2756 ======================
2758 Building U-Boot has been tested in several native build environments
2759 and in many different cross environments. Of course we cannot support
2760 all possibly existing versions of cross development tools in all
2761 (potentially obsolete) versions. In case of tool chain problems we
2762 recommend to use the ELDK (see https://www.denx.de/wiki/DULG/ELDK)
2763 which is extensively used to build and test U-Boot.
2765 If you are not using a native environment, it is assumed that you
2766 have GNU cross compiling tools available in your path. In this case,
2767 you must set the environment variable CROSS_COMPILE in your shell.
2768 Note that no changes to the Makefile or any other source files are
2769 necessary. For example using the ELDK on a 4xx CPU, please enter:
2771 $ CROSS_COMPILE=ppc_4xx-
2772 $ export CROSS_COMPILE
2774 U-Boot is intended to be simple to build. After installing the
2775 sources you must configure U-Boot for one specific board type. This
2780 where "NAME_defconfig" is the name of one of the existing configu-
2781 rations; see configs/*_defconfig for supported names.
2783 Note: for some boards special configuration names may exist; check if
2784 additional information is available from the board vendor; for
2785 instance, the TQM823L systems are available without (standard)
2786 or with LCD support. You can select such additional "features"
2787 when choosing the configuration, i. e.
2789 make TQM823L_defconfig
2790 - will configure for a plain TQM823L, i. e. no LCD support
2792 make TQM823L_LCD_defconfig
2793 - will configure for a TQM823L with U-Boot console on LCD
2798 Finally, type "make all", and you should get some working U-Boot
2799 images ready for download to / installation on your system:
2801 - "u-boot.bin" is a raw binary image
2802 - "u-boot" is an image in ELF binary format
2803 - "u-boot.srec" is in Motorola S-Record format
2805 By default the build is performed locally and the objects are saved
2806 in the source directory. One of the two methods can be used to change
2807 this behavior and build U-Boot to some external directory:
2809 1. Add O= to the make command line invocations:
2811 make O=/tmp/build distclean
2812 make O=/tmp/build NAME_defconfig
2813 make O=/tmp/build all
2815 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
2817 export KBUILD_OUTPUT=/tmp/build
2822 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
2825 User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by
2826 setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS.
2827 For example to treat all compiler warnings as errors:
2829 make KCFLAGS=-Werror
2831 Please be aware that the Makefiles assume you are using GNU make, so
2832 for instance on NetBSD you might need to use "gmake" instead of
2836 If the system board that you have is not listed, then you will need
2837 to port U-Boot to your hardware platform. To do this, follow these
2840 1. Create a new directory to hold your board specific code. Add any
2841 files you need. In your board directory, you will need at least
2842 the "Makefile" and a "<board>.c".
2843 2. Create a new configuration file "include/configs/<board>.h" for
2845 3. If you're porting U-Boot to a new CPU, then also create a new
2846 directory to hold your CPU specific code. Add any files you need.
2847 4. Run "make <board>_defconfig" with your new name.
2848 5. Type "make", and you should get a working "u-boot.srec" file
2849 to be installed on your target system.
2850 6. Debug and solve any problems that might arise.
2851 [Of course, this last step is much harder than it sounds.]
2854 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2855 ==============================================================
2857 If you have modified U-Boot sources (for instance added a new board
2858 or support for new devices, a new CPU, etc.) you are expected to
2859 provide feedback to the other developers. The feedback normally takes
2860 the form of a "patch", i.e. a context diff against a certain (latest
2861 official or latest in the git repository) version of U-Boot sources.
2863 But before you submit such a patch, please verify that your modifi-
2864 cation did not break existing code. At least make sure that *ALL* of
2865 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2866 just run the buildman script (tools/buildman/buildman), which will
2867 configure and build U-Boot for ALL supported system. Be warned, this
2868 will take a while. Please see the buildman README, or run 'buildman -H'
2872 See also "U-Boot Porting Guide" below.
2875 Monitor Commands - Overview:
2876 ============================
2878 go - start application at address 'addr'
2879 run - run commands in an environment variable
2880 bootm - boot application image from memory
2881 bootp - boot image via network using BootP/TFTP protocol
2882 bootz - boot zImage from memory
2883 tftpboot- boot image via network using TFTP protocol
2884 and env variables "ipaddr" and "serverip"
2885 (and eventually "gatewayip")
2886 tftpput - upload a file via network using TFTP protocol
2887 rarpboot- boot image via network using RARP/TFTP protocol
2888 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2889 loads - load S-Record file over serial line
2890 loadb - load binary file over serial line (kermit mode)
2892 mm - memory modify (auto-incrementing)
2893 nm - memory modify (constant address)
2894 mw - memory write (fill)
2897 cmp - memory compare
2898 crc32 - checksum calculation
2899 i2c - I2C sub-system
2900 sspi - SPI utility commands
2901 base - print or set address offset
2902 printenv- print environment variables
2903 pwm - control pwm channels
2904 setenv - set environment variables
2905 saveenv - save environment variables to persistent storage
2906 protect - enable or disable FLASH write protection
2907 erase - erase FLASH memory
2908 flinfo - print FLASH memory information
2909 nand - NAND memory operations (see doc/README.nand)
2910 bdinfo - print Board Info structure
2911 iminfo - print header information for application image
2912 coninfo - print console devices and informations
2913 ide - IDE sub-system
2914 loop - infinite loop on address range
2915 loopw - infinite write loop on address range
2916 mtest - simple RAM test
2917 icache - enable or disable instruction cache
2918 dcache - enable or disable data cache
2919 reset - Perform RESET of the CPU
2920 echo - echo args to console
2921 version - print monitor version
2922 help - print online help
2923 ? - alias for 'help'
2926 Monitor Commands - Detailed Description:
2927 ========================================
2931 For now: just type "help <command>".
2934 Note for Redundant Ethernet Interfaces:
2935 =======================================
2937 Some boards come with redundant Ethernet interfaces; U-Boot supports
2938 such configurations and is capable of automatic selection of a
2939 "working" interface when needed. MAC assignment works as follows:
2941 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2942 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2943 "eth1addr" (=>eth1), "eth2addr", ...
2945 If the network interface stores some valid MAC address (for instance
2946 in SROM), this is used as default address if there is NO correspon-
2947 ding setting in the environment; if the corresponding environment
2948 variable is set, this overrides the settings in the card; that means:
2950 o If the SROM has a valid MAC address, and there is no address in the
2951 environment, the SROM's address is used.
2953 o If there is no valid address in the SROM, and a definition in the
2954 environment exists, then the value from the environment variable is
2957 o If both the SROM and the environment contain a MAC address, and
2958 both addresses are the same, this MAC address is used.
2960 o If both the SROM and the environment contain a MAC address, and the
2961 addresses differ, the value from the environment is used and a
2964 o If neither SROM nor the environment contain a MAC address, an error
2965 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
2966 a random, locally-assigned MAC is used.
2968 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
2969 will be programmed into hardware as part of the initialization process. This
2970 may be skipped by setting the appropriate 'ethmacskip' environment variable.
2971 The naming convention is as follows:
2972 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
2977 U-Boot is capable of booting (and performing other auxiliary operations on)
2978 images in two formats:
2980 New uImage format (FIT)
2981 -----------------------
2983 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
2984 to Flattened Device Tree). It allows the use of images with multiple
2985 components (several kernels, ramdisks, etc.), with contents protected by
2986 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
2992 Old image format is based on binary files which can be basically anything,
2993 preceded by a special header; see the definitions in include/image.h for
2994 details; basically, the header defines the following image properties:
2996 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2997 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2998 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
2999 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3001 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
3002 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3003 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC).
3004 * Compression Type (uncompressed, gzip, bzip2)
3010 The header is marked by a special Magic Number, and both the header
3011 and the data portions of the image are secured against corruption by
3018 Although U-Boot should support any OS or standalone application
3019 easily, the main focus has always been on Linux during the design of
3022 U-Boot includes many features that so far have been part of some
3023 special "boot loader" code within the Linux kernel. Also, any
3024 "initrd" images to be used are no longer part of one big Linux image;
3025 instead, kernel and "initrd" are separate images. This implementation
3026 serves several purposes:
3028 - the same features can be used for other OS or standalone
3029 applications (for instance: using compressed images to reduce the
3030 Flash memory footprint)
3032 - it becomes much easier to port new Linux kernel versions because
3033 lots of low-level, hardware dependent stuff are done by U-Boot
3035 - the same Linux kernel image can now be used with different "initrd"
3036 images; of course this also means that different kernel images can
3037 be run with the same "initrd". This makes testing easier (you don't
3038 have to build a new "zImage.initrd" Linux image when you just
3039 change a file in your "initrd"). Also, a field-upgrade of the
3040 software is easier now.
3046 Porting Linux to U-Boot based systems:
3047 ---------------------------------------
3049 U-Boot cannot save you from doing all the necessary modifications to
3050 configure the Linux device drivers for use with your target hardware
3051 (no, we don't intend to provide a full virtual machine interface to
3054 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
3056 Just make sure your machine specific header file (for instance
3057 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3058 Information structure as we define in include/asm-<arch>/u-boot.h,
3059 and make sure that your definition of IMAP_ADDR uses the same value
3060 as your U-Boot configuration in CONFIG_SYS_IMMR.
3062 Note that U-Boot now has a driver model, a unified model for drivers.
3063 If you are adding a new driver, plumb it into driver model. If there
3064 is no uclass available, you are encouraged to create one. See
3068 Configuring the Linux kernel:
3069 -----------------------------
3071 No specific requirements for U-Boot. Make sure you have some root
3072 device (initial ramdisk, NFS) for your target system.
3075 Building a Linux Image:
3076 -----------------------
3078 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3079 not used. If you use recent kernel source, a new build target
3080 "uImage" will exist which automatically builds an image usable by
3081 U-Boot. Most older kernels also have support for a "pImage" target,
3082 which was introduced for our predecessor project PPCBoot and uses a
3083 100% compatible format.
3087 make TQM850L_defconfig
3092 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3093 encapsulate a compressed Linux kernel image with header information,
3094 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3096 * build a standard "vmlinux" kernel image (in ELF binary format):
3098 * convert the kernel into a raw binary image:
3100 ${CROSS_COMPILE}-objcopy -O binary \
3101 -R .note -R .comment \
3102 -S vmlinux linux.bin
3104 * compress the binary image:
3108 * package compressed binary image for U-Boot:
3110 mkimage -A ppc -O linux -T kernel -C gzip \
3111 -a 0 -e 0 -n "Linux Kernel Image" \
3112 -d linux.bin.gz uImage
3115 The "mkimage" tool can also be used to create ramdisk images for use
3116 with U-Boot, either separated from the Linux kernel image, or
3117 combined into one file. "mkimage" encapsulates the images with a 64
3118 byte header containing information about target architecture,
3119 operating system, image type, compression method, entry points, time
3120 stamp, CRC32 checksums, etc.
3122 "mkimage" can be called in two ways: to verify existing images and
3123 print the header information, or to build new images.
3125 In the first form (with "-l" option) mkimage lists the information
3126 contained in the header of an existing U-Boot image; this includes
3127 checksum verification:
3129 tools/mkimage -l image
3130 -l ==> list image header information
3132 The second form (with "-d" option) is used to build a U-Boot image
3133 from a "data file" which is used as image payload:
3135 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3136 -n name -d data_file image
3137 -A ==> set architecture to 'arch'
3138 -O ==> set operating system to 'os'
3139 -T ==> set image type to 'type'
3140 -C ==> set compression type 'comp'
3141 -a ==> set load address to 'addr' (hex)
3142 -e ==> set entry point to 'ep' (hex)
3143 -n ==> set image name to 'name'
3144 -d ==> use image data from 'datafile'
3146 Right now, all Linux kernels for PowerPC systems use the same load
3147 address (0x00000000), but the entry point address depends on the
3150 - 2.2.x kernels have the entry point at 0x0000000C,
3151 - 2.3.x and later kernels have the entry point at 0x00000000.
3153 So a typical call to build a U-Boot image would read:
3155 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3156 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3157 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
3158 > examples/uImage.TQM850L
3159 Image Name: 2.4.4 kernel for TQM850L
3160 Created: Wed Jul 19 02:34:59 2000
3161 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3162 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3163 Load Address: 0x00000000
3164 Entry Point: 0x00000000
3166 To verify the contents of the image (or check for corruption):
3168 -> tools/mkimage -l examples/uImage.TQM850L
3169 Image Name: 2.4.4 kernel for TQM850L
3170 Created: Wed Jul 19 02:34:59 2000
3171 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3172 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3173 Load Address: 0x00000000
3174 Entry Point: 0x00000000
3176 NOTE: for embedded systems where boot time is critical you can trade
3177 speed for memory and install an UNCOMPRESSED image instead: this
3178 needs more space in Flash, but boots much faster since it does not
3179 need to be uncompressed:
3181 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
3182 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3183 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3184 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
3185 > examples/uImage.TQM850L-uncompressed
3186 Image Name: 2.4.4 kernel for TQM850L
3187 Created: Wed Jul 19 02:34:59 2000
3188 Image Type: PowerPC Linux Kernel Image (uncompressed)
3189 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3190 Load Address: 0x00000000
3191 Entry Point: 0x00000000
3194 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3195 when your kernel is intended to use an initial ramdisk:
3197 -> tools/mkimage -n 'Simple Ramdisk Image' \
3198 > -A ppc -O linux -T ramdisk -C gzip \
3199 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3200 Image Name: Simple Ramdisk Image
3201 Created: Wed Jan 12 14:01:50 2000
3202 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3203 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3204 Load Address: 0x00000000
3205 Entry Point: 0x00000000
3207 The "dumpimage" tool can be used to disassemble or list the contents of images
3208 built by mkimage. See dumpimage's help output (-h) for details.
3210 Installing a Linux Image:
3211 -------------------------
3213 To downloading a U-Boot image over the serial (console) interface,
3214 you must convert the image to S-Record format:
3216 objcopy -I binary -O srec examples/image examples/image.srec
3218 The 'objcopy' does not understand the information in the U-Boot
3219 image header, so the resulting S-Record file will be relative to
3220 address 0x00000000. To load it to a given address, you need to
3221 specify the target address as 'offset' parameter with the 'loads'
3224 Example: install the image to address 0x40100000 (which on the
3225 TQM8xxL is in the first Flash bank):
3227 => erase 40100000 401FFFFF
3233 ## Ready for S-Record download ...
3234 ~>examples/image.srec
3235 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3237 15989 15990 15991 15992
3238 [file transfer complete]
3240 ## Start Addr = 0x00000000
3243 You can check the success of the download using the 'iminfo' command;
3244 this includes a checksum verification so you can be sure no data
3245 corruption happened:
3249 ## Checking Image at 40100000 ...
3250 Image Name: 2.2.13 for initrd on TQM850L
3251 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3252 Data Size: 335725 Bytes = 327 kB = 0 MB
3253 Load Address: 00000000
3254 Entry Point: 0000000c
3255 Verifying Checksum ... OK
3261 The "bootm" command is used to boot an application that is stored in
3262 memory (RAM or Flash). In case of a Linux kernel image, the contents
3263 of the "bootargs" environment variable is passed to the kernel as
3264 parameters. You can check and modify this variable using the
3265 "printenv" and "setenv" commands:
3268 => printenv bootargs
3269 bootargs=root=/dev/ram
3271 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3273 => printenv bootargs
3274 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3277 ## Booting Linux kernel at 40020000 ...
3278 Image Name: 2.2.13 for NFS on TQM850L
3279 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3280 Data Size: 381681 Bytes = 372 kB = 0 MB
3281 Load Address: 00000000
3282 Entry Point: 0000000c
3283 Verifying Checksum ... OK
3284 Uncompressing Kernel Image ... OK
3285 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
3286 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3287 time_init: decrementer frequency = 187500000/60
3288 Calibrating delay loop... 49.77 BogoMIPS
3289 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3292 If you want to boot a Linux kernel with initial RAM disk, you pass
3293 the memory addresses of both the kernel and the initrd image (PPBCOOT
3294 format!) to the "bootm" command:
3296 => imi 40100000 40200000
3298 ## Checking Image at 40100000 ...
3299 Image Name: 2.2.13 for initrd on TQM850L
3300 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3301 Data Size: 335725 Bytes = 327 kB = 0 MB
3302 Load Address: 00000000
3303 Entry Point: 0000000c
3304 Verifying Checksum ... OK
3306 ## Checking Image at 40200000 ...
3307 Image Name: Simple Ramdisk Image
3308 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3309 Data Size: 566530 Bytes = 553 kB = 0 MB
3310 Load Address: 00000000
3311 Entry Point: 00000000
3312 Verifying Checksum ... OK
3314 => bootm 40100000 40200000
3315 ## Booting Linux kernel at 40100000 ...
3316 Image Name: 2.2.13 for initrd on TQM850L
3317 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3318 Data Size: 335725 Bytes = 327 kB = 0 MB
3319 Load Address: 00000000
3320 Entry Point: 0000000c
3321 Verifying Checksum ... OK
3322 Uncompressing Kernel Image ... OK
3323 ## Loading RAMDisk Image at 40200000 ...
3324 Image Name: Simple Ramdisk Image
3325 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3326 Data Size: 566530 Bytes = 553 kB = 0 MB
3327 Load Address: 00000000
3328 Entry Point: 00000000
3329 Verifying Checksum ... OK
3330 Loading Ramdisk ... OK
3331 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
3332 Boot arguments: root=/dev/ram
3333 time_init: decrementer frequency = 187500000/60
3334 Calibrating delay loop... 49.77 BogoMIPS
3336 RAMDISK: Compressed image found at block 0
3337 VFS: Mounted root (ext2 filesystem).
3341 Boot Linux and pass a flat device tree:
3344 First, U-Boot must be compiled with the appropriate defines. See the section
3345 titled "Linux Kernel Interface" above for a more in depth explanation. The
3346 following is an example of how to start a kernel and pass an updated
3352 oft=oftrees/mpc8540ads.dtb
3353 => tftp $oftaddr $oft
3354 Speed: 1000, full duplex
3356 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3357 Filename 'oftrees/mpc8540ads.dtb'.
3358 Load address: 0x300000
3361 Bytes transferred = 4106 (100a hex)
3362 => tftp $loadaddr $bootfile
3363 Speed: 1000, full duplex
3365 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3367 Load address: 0x200000
3368 Loading:############
3370 Bytes transferred = 1029407 (fb51f hex)
3375 => bootm $loadaddr - $oftaddr
3376 ## Booting image at 00200000 ...
3377 Image Name: Linux-2.6.17-dirty
3378 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3379 Data Size: 1029343 Bytes = 1005.2 kB
3380 Load Address: 00000000
3381 Entry Point: 00000000
3382 Verifying Checksum ... OK
3383 Uncompressing Kernel Image ... OK
3384 Booting using flat device tree at 0x300000
3385 Using MPC85xx ADS machine description
3386 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3390 More About U-Boot Image Types:
3391 ------------------------------
3393 U-Boot supports the following image types:
3395 "Standalone Programs" are directly runnable in the environment
3396 provided by U-Boot; it is expected that (if they behave
3397 well) you can continue to work in U-Boot after return from
3398 the Standalone Program.
3399 "OS Kernel Images" are usually images of some Embedded OS which
3400 will take over control completely. Usually these programs
3401 will install their own set of exception handlers, device
3402 drivers, set up the MMU, etc. - this means, that you cannot
3403 expect to re-enter U-Boot except by resetting the CPU.
3404 "RAMDisk Images" are more or less just data blocks, and their
3405 parameters (address, size) are passed to an OS kernel that is
3407 "Multi-File Images" contain several images, typically an OS
3408 (Linux) kernel image and one or more data images like
3409 RAMDisks. This construct is useful for instance when you want
3410 to boot over the network using BOOTP etc., where the boot
3411 server provides just a single image file, but you want to get
3412 for instance an OS kernel and a RAMDisk image.
3414 "Multi-File Images" start with a list of image sizes, each
3415 image size (in bytes) specified by an "uint32_t" in network
3416 byte order. This list is terminated by an "(uint32_t)0".
3417 Immediately after the terminating 0 follow the images, one by
3418 one, all aligned on "uint32_t" boundaries (size rounded up to
3419 a multiple of 4 bytes).
3421 "Firmware Images" are binary images containing firmware (like
3422 U-Boot or FPGA images) which usually will be programmed to
3425 "Script files" are command sequences that will be executed by
3426 U-Boot's command interpreter; this feature is especially
3427 useful when you configure U-Boot to use a real shell (hush)
3428 as command interpreter.
3430 Booting the Linux zImage:
3431 -------------------------
3433 On some platforms, it's possible to boot Linux zImage. This is done
3434 using the "bootz" command. The syntax of "bootz" command is the same
3435 as the syntax of "bootm" command.
3437 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
3438 kernel with raw initrd images. The syntax is slightly different, the
3439 address of the initrd must be augmented by it's size, in the following
3440 format: "<initrd addres>:<initrd size>".
3446 One of the features of U-Boot is that you can dynamically load and
3447 run "standalone" applications, which can use some resources of
3448 U-Boot like console I/O functions or interrupt services.
3450 Two simple examples are included with the sources:
3455 'examples/hello_world.c' contains a small "Hello World" Demo
3456 application; it is automatically compiled when you build U-Boot.
3457 It's configured to run at address 0x00040004, so you can play with it
3461 ## Ready for S-Record download ...
3462 ~>examples/hello_world.srec
3463 1 2 3 4 5 6 7 8 9 10 11 ...
3464 [file transfer complete]
3466 ## Start Addr = 0x00040004
3468 => go 40004 Hello World! This is a test.
3469 ## Starting application at 0x00040004 ...
3480 Hit any key to exit ...
3482 ## Application terminated, rc = 0x0
3484 Another example, which demonstrates how to register a CPM interrupt
3485 handler with the U-Boot code, can be found in 'examples/timer.c'.
3486 Here, a CPM timer is set up to generate an interrupt every second.
3487 The interrupt service routine is trivial, just printing a '.'
3488 character, but this is just a demo program. The application can be
3489 controlled by the following keys:
3491 ? - print current values og the CPM Timer registers
3492 b - enable interrupts and start timer
3493 e - stop timer and disable interrupts
3494 q - quit application
3497 ## Ready for S-Record download ...
3498 ~>examples/timer.srec
3499 1 2 3 4 5 6 7 8 9 10 11 ...
3500 [file transfer complete]
3502 ## Start Addr = 0x00040004
3505 ## Starting application at 0x00040004 ...
3508 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3511 [q, b, e, ?] Set interval 1000000 us
3514 [q, b, e, ?] ........
3515 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3518 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3521 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3524 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3526 [q, b, e, ?] ...Stopping timer
3528 [q, b, e, ?] ## Application terminated, rc = 0x0
3534 Over time, many people have reported problems when trying to use the
3535 "minicom" terminal emulation program for serial download. I (wd)
3536 consider minicom to be broken, and recommend not to use it. Under
3537 Unix, I recommend to use C-Kermit for general purpose use (and
3538 especially for kermit binary protocol download ("loadb" command), and
3539 use "cu" for S-Record download ("loads" command). See
3540 https://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
3541 for help with kermit.
3544 Nevertheless, if you absolutely want to use it try adding this
3545 configuration to your "File transfer protocols" section:
3547 Name Program Name U/D FullScr IO-Red. Multi
3548 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3549 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3555 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3556 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3558 Building requires a cross environment; it is known to work on
3559 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3560 need gmake since the Makefiles are not compatible with BSD make).
3561 Note that the cross-powerpc package does not install include files;
3562 attempting to build U-Boot will fail because <machine/ansi.h> is
3563 missing. This file has to be installed and patched manually:
3565 # cd /usr/pkg/cross/powerpc-netbsd/include
3567 # ln -s powerpc machine
3568 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3569 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3571 Native builds *don't* work due to incompatibilities between native
3572 and U-Boot include files.
3574 Booting assumes that (the first part of) the image booted is a
3575 stage-2 loader which in turn loads and then invokes the kernel
3576 proper. Loader sources will eventually appear in the NetBSD source
3577 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3578 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3581 Implementation Internals:
3582 =========================
3584 The following is not intended to be a complete description of every
3585 implementation detail. However, it should help to understand the
3586 inner workings of U-Boot and make it easier to port it to custom
3590 Initial Stack, Global Data:
3591 ---------------------------
3593 The implementation of U-Boot is complicated by the fact that U-Boot
3594 starts running out of ROM (flash memory), usually without access to
3595 system RAM (because the memory controller is not initialized yet).
3596 This means that we don't have writable Data or BSS segments, and BSS
3597 is not initialized as zero. To be able to get a C environment working
3598 at all, we have to allocate at least a minimal stack. Implementation
3599 options for this are defined and restricted by the CPU used: Some CPU
3600 models provide on-chip memory (like the IMMR area on MPC8xx and
3601 MPC826x processors), on others (parts of) the data cache can be
3602 locked as (mis-) used as memory, etc.
3604 Chris Hallinan posted a good summary of these issues to the
3605 U-Boot mailing list:
3607 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3608 From: "Chris Hallinan" <clh@net1plus.com>
3609 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3612 Correct me if I'm wrong, folks, but the way I understand it
3613 is this: Using DCACHE as initial RAM for Stack, etc, does not
3614 require any physical RAM backing up the cache. The cleverness
3615 is that the cache is being used as a temporary supply of
3616 necessary storage before the SDRAM controller is setup. It's
3617 beyond the scope of this list to explain the details, but you
3618 can see how this works by studying the cache architecture and
3619 operation in the architecture and processor-specific manuals.
3621 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3622 is another option for the system designer to use as an
3623 initial stack/RAM area prior to SDRAM being available. Either
3624 option should work for you. Using CS 4 should be fine if your
3625 board designers haven't used it for something that would
3626 cause you grief during the initial boot! It is frequently not
3629 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
3630 with your processor/board/system design. The default value
3631 you will find in any recent u-boot distribution in
3632 walnut.h should work for you. I'd set it to a value larger
3633 than your SDRAM module. If you have a 64MB SDRAM module, set
3634 it above 400_0000. Just make sure your board has no resources
3635 that are supposed to respond to that address! That code in
3636 start.S has been around a while and should work as is when
3637 you get the config right.
3642 It is essential to remember this, since it has some impact on the C
3643 code for the initialization procedures:
3645 * Initialized global data (data segment) is read-only. Do not attempt
3648 * Do not use any uninitialized global data (or implicitly initialized
3649 as zero data - BSS segment) at all - this is undefined, initiali-
3650 zation is performed later (when relocating to RAM).
3652 * Stack space is very limited. Avoid big data buffers or things like
3655 Having only the stack as writable memory limits means we cannot use
3656 normal global data to share information between the code. But it
3657 turned out that the implementation of U-Boot can be greatly
3658 simplified by making a global data structure (gd_t) available to all
3659 functions. We could pass a pointer to this data as argument to _all_
3660 functions, but this would bloat the code. Instead we use a feature of
3661 the GCC compiler (Global Register Variables) to share the data: we
3662 place a pointer (gd) to the global data into a register which we
3663 reserve for this purpose.
3665 When choosing a register for such a purpose we are restricted by the
3666 relevant (E)ABI specifications for the current architecture, and by
3667 GCC's implementation.
3669 For PowerPC, the following registers have specific use:
3671 R2: reserved for system use
3672 R3-R4: parameter passing and return values
3673 R5-R10: parameter passing
3674 R13: small data area pointer
3678 (U-Boot also uses R12 as internal GOT pointer. r12
3679 is a volatile register so r12 needs to be reset when
3680 going back and forth between asm and C)
3682 ==> U-Boot will use R2 to hold a pointer to the global data
3684 Note: on PPC, we could use a static initializer (since the
3685 address of the global data structure is known at compile time),
3686 but it turned out that reserving a register results in somewhat
3687 smaller code - although the code savings are not that big (on
3688 average for all boards 752 bytes for the whole U-Boot image,
3689 624 text + 127 data).
3691 On ARM, the following registers are used:
3693 R0: function argument word/integer result
3694 R1-R3: function argument word
3695 R9: platform specific
3696 R10: stack limit (used only if stack checking is enabled)
3697 R11: argument (frame) pointer
3698 R12: temporary workspace
3701 R15: program counter
3703 ==> U-Boot will use R9 to hold a pointer to the global data
3705 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
3707 On Nios II, the ABI is documented here:
3708 https://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
3710 ==> U-Boot will use gp to hold a pointer to the global data
3712 Note: on Nios II, we give "-G0" option to gcc and don't use gp
3713 to access small data sections, so gp is free.
3715 On NDS32, the following registers are used:
3717 R0-R1: argument/return
3719 R15: temporary register for assembler
3720 R16: trampoline register
3721 R28: frame pointer (FP)
3722 R29: global pointer (GP)
3723 R30: link register (LP)
3724 R31: stack pointer (SP)
3725 PC: program counter (PC)
3727 ==> U-Boot will use R10 to hold a pointer to the global data
3729 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3730 or current versions of GCC may "optimize" the code too much.
3732 On RISC-V, the following registers are used:
3734 x0: hard-wired zero (zero)
3735 x1: return address (ra)
3736 x2: stack pointer (sp)
3737 x3: global pointer (gp)
3738 x4: thread pointer (tp)
3739 x5: link register (t0)
3740 x8: frame pointer (fp)
3741 x10-x11: arguments/return values (a0-1)
3742 x12-x17: arguments (a2-7)
3743 x28-31: temporaries (t3-6)
3744 pc: program counter (pc)
3746 ==> U-Boot will use gp to hold a pointer to the global data
3751 U-Boot runs in system state and uses physical addresses, i.e. the
3752 MMU is not used either for address mapping nor for memory protection.
3754 The available memory is mapped to fixed addresses using the memory
3755 controller. In this process, a contiguous block is formed for each
3756 memory type (Flash, SDRAM, SRAM), even when it consists of several
3757 physical memory banks.
3759 U-Boot is installed in the first 128 kB of the first Flash bank (on
3760 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3761 booting and sizing and initializing DRAM, the code relocates itself
3762 to the upper end of DRAM. Immediately below the U-Boot code some
3763 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
3764 configuration setting]. Below that, a structure with global Board
3765 Info data is placed, followed by the stack (growing downward).
3767 Additionally, some exception handler code is copied to the low 8 kB
3768 of DRAM (0x00000000 ... 0x00001FFF).
3770 So a typical memory configuration with 16 MB of DRAM could look like
3773 0x0000 0000 Exception Vector code
3776 0x0000 2000 Free for Application Use
3782 0x00FB FF20 Monitor Stack (Growing downward)
3783 0x00FB FFAC Board Info Data and permanent copy of global data
3784 0x00FC 0000 Malloc Arena
3787 0x00FE 0000 RAM Copy of Monitor Code
3788 ... eventually: LCD or video framebuffer
3789 ... eventually: pRAM (Protected RAM - unchanged by reset)
3790 0x00FF FFFF [End of RAM]
3793 System Initialization:
3794 ----------------------
3796 In the reset configuration, U-Boot starts at the reset entry point
3797 (on most PowerPC systems at address 0x00000100). Because of the reset
3798 configuration for CS0# this is a mirror of the on board Flash memory.
3799 To be able to re-map memory U-Boot then jumps to its link address.
3800 To be able to implement the initialization code in C, a (small!)
3801 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3802 which provide such a feature like), or in a locked part of the data
3803 cache. After that, U-Boot initializes the CPU core, the caches and
3806 Next, all (potentially) available memory banks are mapped using a
3807 preliminary mapping. For example, we put them on 512 MB boundaries
3808 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3809 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3810 programmed for SDRAM access. Using the temporary configuration, a
3811 simple memory test is run that determines the size of the SDRAM
3814 When there is more than one SDRAM bank, and the banks are of
3815 different size, the largest is mapped first. For equal size, the first
3816 bank (CS2#) is mapped first. The first mapping is always for address
3817 0x00000000, with any additional banks following immediately to create
3818 contiguous memory starting from 0.
3820 Then, the monitor installs itself at the upper end of the SDRAM area
3821 and allocates memory for use by malloc() and for the global Board
3822 Info data; also, the exception vector code is copied to the low RAM
3823 pages, and the final stack is set up.
3825 Only after this relocation will you have a "normal" C environment;
3826 until that you are restricted in several ways, mostly because you are
3827 running from ROM, and because the code will have to be relocated to a
3831 U-Boot Porting Guide:
3832 ----------------------
3834 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3838 int main(int argc, char *argv[])
3840 sighandler_t no_more_time;
3842 signal(SIGALRM, no_more_time);
3843 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
3845 if (available_money > available_manpower) {
3846 Pay consultant to port U-Boot;
3850 Download latest U-Boot source;
3852 Subscribe to u-boot mailing list;
3855 email("Hi, I am new to U-Boot, how do I get started?");
3858 Read the README file in the top level directory;
3859 Read https://www.denx.de/wiki/bin/view/DULG/Manual;
3860 Read applicable doc/README.*;
3861 Read the source, Luke;
3862 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
3865 if (available_money > toLocalCurrency ($2500))
3868 Add a lot of aggravation and time;
3870 if (a similar board exists) { /* hopefully... */
3871 cp -a board/<similar> board/<myboard>
3872 cp include/configs/<similar>.h include/configs/<myboard>.h
3874 Create your own board support subdirectory;
3875 Create your own board include/configs/<myboard>.h file;
3877 Edit new board/<myboard> files
3878 Edit new include/configs/<myboard>.h
3883 Add / modify source code;
3887 email("Hi, I am having problems...");
3889 Send patch file to the U-Boot email list;
3890 if (reasonable critiques)
3891 Incorporate improvements from email list code review;
3893 Defend code as written;
3899 void no_more_time (int sig)
3908 All contributions to U-Boot should conform to the Linux kernel
3909 coding style; see the kernel coding style guide at
3910 https://www.kernel.org/doc/html/latest/process/coding-style.html, and the
3911 script "scripts/Lindent" in your Linux kernel source directory.
3913 Source files originating from a different project (for example the
3914 MTD subsystem) are generally exempt from these guidelines and are not
3915 reformatted to ease subsequent migration to newer versions of those
3918 Please note that U-Boot is implemented in C (and to some small parts in
3919 Assembler); no C++ is used, so please do not use C++ style comments (//)
3922 Please also stick to the following formatting rules:
3923 - remove any trailing white space
3924 - use TAB characters for indentation and vertical alignment, not spaces
3925 - make sure NOT to use DOS '\r\n' line feeds
3926 - do not add more than 2 consecutive empty lines to source files
3927 - do not add trailing empty lines to source files
3929 Submissions which do not conform to the standards may be returned
3930 with a request to reformat the changes.
3936 Since the number of patches for U-Boot is growing, we need to
3937 establish some rules. Submissions which do not conform to these rules
3938 may be rejected, even when they contain important and valuable stuff.
3940 Please see https://www.denx.de/wiki/U-Boot/Patches for details.
3942 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
3943 see https://lists.denx.de/listinfo/u-boot
3945 When you send a patch, please include the following information with
3948 * For bug fixes: a description of the bug and how your patch fixes
3949 this bug. Please try to include a way of demonstrating that the
3950 patch actually fixes something.
3952 * For new features: a description of the feature and your
3955 * For major contributions, add a MAINTAINERS file with your
3956 information and associated file and directory references.
3958 * When you add support for a new board, don't forget to add a
3959 maintainer e-mail address to the boards.cfg file, too.
3961 * If your patch adds new configuration options, don't forget to
3962 document these in the README file.
3964 * The patch itself. If you are using git (which is *strongly*
3965 recommended) you can easily generate the patch using the
3966 "git format-patch". If you then use "git send-email" to send it to
3967 the U-Boot mailing list, you will avoid most of the common problems
3968 with some other mail clients.
3970 If you cannot use git, use "diff -purN OLD NEW". If your version of
3971 diff does not support these options, then get the latest version of
3974 The current directory when running this command shall be the parent
3975 directory of the U-Boot source tree (i. e. please make sure that
3976 your patch includes sufficient directory information for the
3979 We prefer patches as plain text. MIME attachments are discouraged,
3980 and compressed attachments must not be used.
3982 * If one logical set of modifications affects or creates several
3983 files, all these changes shall be submitted in a SINGLE patch file.
3985 * Changesets that contain different, unrelated modifications shall be
3986 submitted as SEPARATE patches, one patch per changeset.
3991 * Before sending the patch, run the buildman script on your patched
3992 source tree and make sure that no errors or warnings are reported
3993 for any of the boards.
3995 * Keep your modifications to the necessary minimum: A patch
3996 containing several unrelated changes or arbitrary reformats will be
3997 returned with a request to re-formatting / split it.
3999 * If you modify existing code, make sure that your new code does not
4000 add to the memory footprint of the code ;-) Small is beautiful!
4001 When adding new features, these should compile conditionally only
4002 (using #ifdef), and the resulting code with the new feature
4003 disabled must not need more memory than the old code without your
4006 * Remember that there is a size limit of 100 kB per message on the
4007 u-boot mailing list. Bigger patches will be moderated. If they are
4008 reasonable and not too big, they will be acknowledged. But patches
4009 bigger than the size limit should be avoided.