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
570 U-Boot can detect if an IDE device is present or not.
571 If not, and this new config option is activated, U-Boot
572 removes the ATA node from the DTS before booting Linux,
573 so the Linux IDE driver does not probe the device and
574 crash. This is needed for buggy hardware (uc101) where
575 no pull down resistor is connected to the signal IDE5V_DD7.
577 - vxWorks boot parameters:
579 bootvx constructs a valid bootline using the following
580 environments variables: bootdev, bootfile, ipaddr, netmask,
581 serverip, gatewayip, hostname, othbootargs.
582 It loads the vxWorks image pointed bootfile.
584 Note: If a "bootargs" environment is defined, it will override
585 the defaults discussed just above.
587 - Cache Configuration for ARM:
588 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
590 CONFIG_SYS_PL310_BASE - Physical base address of PL310
591 controller register space
596 If you have Amba PrimeCell PL011 UARTs, set this variable to
597 the clock speed of the UARTs.
601 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
602 define this to a list of base addresses for each (supported)
603 port. See e.g. include/configs/versatile.h
605 CONFIG_SERIAL_HW_FLOW_CONTROL
607 Define this variable to enable hw flow control in serial driver.
608 Current user of this option is drivers/serial/nsl16550.c driver
610 - Serial Download Echo Mode:
612 If defined to 1, all characters received during a
613 serial download (using the "loads" command) are
614 echoed back. This might be needed by some terminal
615 emulations (like "cu"), but may as well just take
616 time on others. This setting #define's the initial
617 value of the "loads_echo" environment variable.
619 - Removal of commands
620 If no commands are needed to boot, you can disable
621 CONFIG_CMDLINE to remove them. In this case, the command line
622 will not be available, and when U-Boot wants to execute the
623 boot command (on start-up) it will call board_run_command()
624 instead. This can reduce image size significantly for very
625 simple boot procedures.
627 - Regular expression support:
629 If this variable is defined, U-Boot is linked against
630 the SLRE (Super Light Regular Expression) library,
631 which adds regex support to some commands, as for
632 example "env grep" and "setexpr".
635 CONFIG_SYS_WATCHDOG_FREQ
636 Some platforms automatically call WATCHDOG_RESET()
637 from the timer interrupt handler every
638 CONFIG_SYS_WATCHDOG_FREQ interrupts. If not set by the
639 board configuration file, a default of CONFIG_SYS_HZ/2
640 (i.e. 500) is used. Setting CONFIG_SYS_WATCHDOG_FREQ
641 to 0 disables calling WATCHDOG_RESET() from the timer
646 When CONFIG_CMD_DATE is selected, the type of the RTC
647 has to be selected, too. Define exactly one of the
650 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
651 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
652 CONFIG_RTC_MC146818 - use MC146818 RTC
653 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
654 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
655 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
656 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
657 CONFIG_RTC_DS164x - use Dallas DS164x RTC
658 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
659 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
660 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
661 CONFIG_SYS_RV3029_TCR - enable trickle charger on
664 Note that if the RTC uses I2C, then the I2C interface
665 must also be configured. See I2C Support, below.
668 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
670 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
671 chip-ngpio pairs that tell the PCA953X driver the number of
672 pins supported by a particular chip.
674 Note that if the GPIO device uses I2C, then the I2C interface
675 must also be configured. See I2C Support, below.
678 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
679 accesses and can checksum them or write a list of them out
680 to memory. See the 'iotrace' command for details. This is
681 useful for testing device drivers since it can confirm that
682 the driver behaves the same way before and after a code
683 change. Currently this is supported on sandbox and arm. To
684 add support for your architecture, add '#include <iotrace.h>'
685 to the bottom of arch/<arch>/include/asm/io.h and test.
687 Example output from the 'iotrace stats' command is below.
688 Note that if the trace buffer is exhausted, the checksum will
689 still continue to operate.
692 Start: 10000000 (buffer start address)
693 Size: 00010000 (buffer size)
694 Offset: 00000120 (current buffer offset)
695 Output: 10000120 (start + offset)
696 Count: 00000018 (number of trace records)
697 CRC32: 9526fb66 (CRC32 of all trace records)
701 When CONFIG_TIMESTAMP is selected, the timestamp
702 (date and time) of an image is printed by image
703 commands like bootm or iminfo. This option is
704 automatically enabled when you select CONFIG_CMD_DATE .
706 - Partition Labels (disklabels) Supported:
707 Zero or more of the following:
708 CONFIG_MAC_PARTITION Apple's MacOS partition table.
709 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
710 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
711 bootloader. Note 2TB partition limit; see
713 CONFIG_SCSI) you must configure support for at
714 least one non-MTD partition type as well.
719 Set this to enable support for disks larger than 137GB
720 Also look at CONFIG_SYS_64BIT_LBA.
721 Whithout these , LBA48 support uses 32bit variables and will 'only'
722 support disks up to 2.1TB.
724 CONFIG_SYS_64BIT_LBA:
725 When enabled, makes the IDE subsystem use 64bit sector addresses.
728 - NETWORK Support (PCI):
730 Utility code for direct access to the SPI bus on Intel 8257x.
731 This does not do anything useful unless you set at least one
732 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
735 Support for National dp83815 chips.
738 Support for National dp8382[01] gigabit chips.
740 - NETWORK Support (other):
742 Support for the Calxeda XGMAC device
745 Support for SMSC's LAN91C96 chips.
747 CONFIG_LAN91C96_USE_32_BIT
748 Define this to enable 32 bit addressing
751 Support for SMSC's LAN91C111 chip
754 Define this to hold the physical address
755 of the device (I/O space)
757 CONFIG_SMC_USE_32_BIT
758 Define this if data bus is 32 bits
760 CONFIG_SMC_USE_IOFUNCS
761 Define this to use i/o functions instead of macros
762 (some hardware wont work with macros)
764 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
765 Define this if you have more then 3 PHYs.
768 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
770 CONFIG_FTGMAC100_EGIGA
771 Define this to use GE link update with gigabit PHY.
772 Define this if FTGMAC100 is connected to gigabit PHY.
773 If your system has 10/100 PHY only, it might not occur
774 wrong behavior. Because PHY usually return timeout or
775 useless data when polling gigabit status and gigabit
776 control registers. This behavior won't affect the
777 correctnessof 10/100 link speed update.
780 Support for Renesas on-chip Ethernet controller
782 CONFIG_SH_ETHER_USE_PORT
783 Define the number of ports to be used
785 CONFIG_SH_ETHER_PHY_ADDR
786 Define the ETH PHY's address
788 CONFIG_SH_ETHER_CACHE_WRITEBACK
789 If this option is set, the driver enables cache flush.
795 CONFIG_TPM_TIS_INFINEON
796 Support for Infineon i2c bus TPM devices. Only one device
797 per system is supported at this time.
799 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
800 Define the burst count bytes upper limit
803 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
805 CONFIG_TPM_ST33ZP24_I2C
806 Support for STMicroelectronics ST33ZP24 I2C devices.
807 Requires TPM_ST33ZP24 and I2C.
809 CONFIG_TPM_ST33ZP24_SPI
810 Support for STMicroelectronics ST33ZP24 SPI devices.
811 Requires TPM_ST33ZP24 and SPI.
814 Support for Atmel TWI TPM device. Requires I2C support.
817 Support for generic parallel port TPM devices. Only one device
818 per system is supported at this time.
820 CONFIG_TPM_TIS_BASE_ADDRESS
821 Base address where the generic TPM device is mapped
822 to. Contemporary x86 systems usually map it at
826 Define this to enable the TPM support library which provides
827 functional interfaces to some TPM commands.
828 Requires support for a TPM device.
830 CONFIG_TPM_AUTH_SESSIONS
831 Define this to enable authorized functions in the TPM library.
832 Requires CONFIG_TPM and CONFIG_SHA1.
835 At the moment only the UHCI host controller is
836 supported (PIP405, MIP405); define
837 CONFIG_USB_UHCI to enable it.
838 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
839 and define CONFIG_USB_STORAGE to enable the USB
842 Supported are USB Keyboards and USB Floppy drives
845 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
846 txfilltuning field in the EHCI controller on reset.
848 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
852 Define the below if you wish to use the USB console.
853 Once firmware is rebuilt from a serial console issue the
854 command "setenv stdin usbtty; setenv stdout usbtty" and
855 attach your USB cable. The Unix command "dmesg" should print
856 it has found a new device. The environment variable usbtty
857 can be set to gserial or cdc_acm to enable your device to
858 appear to a USB host as a Linux gserial device or a
859 Common Device Class Abstract Control Model serial device.
860 If you select usbtty = gserial you should be able to enumerate
862 # modprobe usbserial vendor=0xVendorID product=0xProductID
863 else if using cdc_acm, simply setting the environment
864 variable usbtty to be cdc_acm should suffice. The following
865 might be defined in YourBoardName.h
868 Define this to build a UDC device
871 Define this to have a tty type of device available to
872 talk to the UDC device
875 Define this to enable the high speed support for usb
876 device and usbtty. If this feature is enabled, a routine
877 int is_usbd_high_speed(void)
878 also needs to be defined by the driver to dynamically poll
879 whether the enumeration has succeded at high speed or full
882 If you have a USB-IF assigned VendorID then you may wish to
883 define your own vendor specific values either in BoardName.h
884 or directly in usbd_vendor_info.h. If you don't define
885 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
886 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
887 should pretend to be a Linux device to it's target host.
889 CONFIG_USBD_MANUFACTURER
890 Define this string as the name of your company for
891 - CONFIG_USBD_MANUFACTURER "my company"
893 CONFIG_USBD_PRODUCT_NAME
894 Define this string as the name of your product
895 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
898 Define this as your assigned Vendor ID from the USB
899 Implementors Forum. This *must* be a genuine Vendor ID
900 to avoid polluting the USB namespace.
901 - CONFIG_USBD_VENDORID 0xFFFF
903 CONFIG_USBD_PRODUCTID
904 Define this as the unique Product ID
906 - CONFIG_USBD_PRODUCTID 0xFFFF
908 - ULPI Layer Support:
909 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
910 the generic ULPI layer. The generic layer accesses the ULPI PHY
911 via the platform viewport, so you need both the genric layer and
912 the viewport enabled. Currently only Chipidea/ARC based
913 viewport is supported.
914 To enable the ULPI layer support, define CONFIG_USB_ULPI and
915 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
916 If your ULPI phy needs a different reference clock than the
917 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
918 the appropriate value in Hz.
921 The MMC controller on the Intel PXA is supported. To
922 enable this define CONFIG_MMC. The MMC can be
923 accessed from the boot prompt by mapping the device
924 to physical memory similar to flash. Command line is
925 enabled with CONFIG_CMD_MMC. The MMC driver also works with
926 the FAT fs. This is enabled with CONFIG_CMD_FAT.
929 Support for Renesas on-chip MMCIF controller
932 Define the base address of MMCIF registers
935 Define the clock frequency for MMCIF
937 - USB Device Firmware Update (DFU) class support:
939 This enables the USB portion of the DFU USB class
942 This enables support for exposing NAND devices via DFU.
945 This enables support for exposing RAM via DFU.
946 Note: DFU spec refer to non-volatile memory usage, but
947 allow usages beyond the scope of spec - here RAM usage,
948 one that would help mostly the developer.
950 CONFIG_SYS_DFU_DATA_BUF_SIZE
951 Dfu transfer uses a buffer before writing data to the
952 raw storage device. Make the size (in bytes) of this buffer
953 configurable. The size of this buffer is also configurable
954 through the "dfu_bufsiz" environment variable.
956 CONFIG_SYS_DFU_MAX_FILE_SIZE
957 When updating files rather than the raw storage device,
958 we use a static buffer to copy the file into and then write
959 the buffer once we've been given the whole file. Define
960 this to the maximum filesize (in bytes) for the buffer.
961 Default is 4 MiB if undefined.
963 DFU_DEFAULT_POLL_TIMEOUT
964 Poll timeout [ms], is the timeout a device can send to the
965 host. The host must wait for this timeout before sending
966 a subsequent DFU_GET_STATUS request to the device.
968 DFU_MANIFEST_POLL_TIMEOUT
969 Poll timeout [ms], which the device sends to the host when
970 entering dfuMANIFEST state. Host waits this timeout, before
971 sending again an USB request to the device.
973 - Journaling Flash filesystem support:
974 CONFIG_SYS_JFFS2_FIRST_SECTOR,
975 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
976 Define these for a default partition on a NOR device
979 See Kconfig help for available keyboard drivers.
983 Enable the Freescale DIU video driver. Reference boards for
984 SOCs that have a DIU should define this macro to enable DIU
985 support, and should also define these other macros:
990 CONFIG_VIDEO_SW_CURSOR
991 CONFIG_VGA_AS_SINGLE_DEVICE
992 CONFIG_VIDEO_BMP_LOGO
994 The DIU driver will look for the 'video-mode' environment
995 variable, and if defined, enable the DIU as a console during
996 boot. See the documentation file doc/README.video for a
997 description of this variable.
999 - LCD Support: CONFIG_LCD
1001 Define this to enable LCD support (for output to LCD
1002 display); also select one of the supported displays
1003 by defining one of these:
1007 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1009 CONFIG_NEC_NL6448AC33:
1011 NEC NL6448AC33-18. Active, color, single scan.
1013 CONFIG_NEC_NL6448BC20
1015 NEC NL6448BC20-08. 6.5", 640x480.
1016 Active, color, single scan.
1018 CONFIG_NEC_NL6448BC33_54
1020 NEC NL6448BC33-54. 10.4", 640x480.
1021 Active, color, single scan.
1025 Sharp 320x240. Active, color, single scan.
1026 It isn't 16x9, and I am not sure what it is.
1028 CONFIG_SHARP_LQ64D341
1030 Sharp LQ64D341 display, 640x480.
1031 Active, color, single scan.
1035 HLD1045 display, 640x480.
1036 Active, color, single scan.
1040 Optrex CBL50840-2 NF-FW 99 22 M5
1042 Hitachi LMG6912RPFC-00T
1046 320x240. Black & white.
1048 CONFIG_LCD_ALIGNMENT
1050 Normally the LCD is page-aligned (typically 4KB). If this is
1051 defined then the LCD will be aligned to this value instead.
1052 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1053 here, since it is cheaper to change data cache settings on
1054 a per-section basis.
1059 Sometimes, for example if the display is mounted in portrait
1060 mode or even if it's mounted landscape but rotated by 180degree,
1061 we need to rotate our content of the display relative to the
1062 framebuffer, so that user can read the messages which are
1064 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1065 initialized with a given rotation from "vl_rot" out of
1066 "vidinfo_t" which is provided by the board specific code.
1067 The value for vl_rot is coded as following (matching to
1068 fbcon=rotate:<n> linux-kernel commandline):
1069 0 = no rotation respectively 0 degree
1070 1 = 90 degree rotation
1071 2 = 180 degree rotation
1072 3 = 270 degree rotation
1074 If CONFIG_LCD_ROTATION is not defined, the console will be
1075 initialized with 0degree rotation.
1079 Support drawing of RLE8-compressed bitmaps on the LCD.
1082 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1084 The clock frequency of the MII bus
1086 CONFIG_PHY_RESET_DELAY
1088 Some PHY like Intel LXT971A need extra delay after
1089 reset before any MII register access is possible.
1090 For such PHY, set this option to the usec delay
1091 required. (minimum 300usec for LXT971A)
1093 CONFIG_PHY_CMD_DELAY (ppc4xx)
1095 Some PHY like Intel LXT971A need extra delay after
1096 command issued before MII status register can be read
1101 Define a default value for the IP address to use for
1102 the default Ethernet interface, in case this is not
1103 determined through e.g. bootp.
1104 (Environment variable "ipaddr")
1106 - Server IP address:
1109 Defines a default value for the IP address of a TFTP
1110 server to contact when using the "tftboot" command.
1111 (Environment variable "serverip")
1113 - Gateway IP address:
1116 Defines a default value for the IP address of the
1117 default router where packets to other networks are
1119 (Environment variable "gatewayip")
1124 Defines a default value for the subnet mask (or
1125 routing prefix) which is used to determine if an IP
1126 address belongs to the local subnet or needs to be
1127 forwarded through a router.
1128 (Environment variable "netmask")
1130 - BOOTP Recovery Mode:
1131 CONFIG_BOOTP_RANDOM_DELAY
1133 If you have many targets in a network that try to
1134 boot using BOOTP, you may want to avoid that all
1135 systems send out BOOTP requests at precisely the same
1136 moment (which would happen for instance at recovery
1137 from a power failure, when all systems will try to
1138 boot, thus flooding the BOOTP server. Defining
1139 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1140 inserted before sending out BOOTP requests. The
1141 following delays are inserted then:
1143 1st BOOTP request: delay 0 ... 1 sec
1144 2nd BOOTP request: delay 0 ... 2 sec
1145 3rd BOOTP request: delay 0 ... 4 sec
1147 BOOTP requests: delay 0 ... 8 sec
1149 CONFIG_BOOTP_ID_CACHE_SIZE
1151 BOOTP packets are uniquely identified using a 32-bit ID. The
1152 server will copy the ID from client requests to responses and
1153 U-Boot will use this to determine if it is the destination of
1154 an incoming response. Some servers will check that addresses
1155 aren't in use before handing them out (usually using an ARP
1156 ping) and therefore take up to a few hundred milliseconds to
1157 respond. Network congestion may also influence the time it
1158 takes for a response to make it back to the client. If that
1159 time is too long, U-Boot will retransmit requests. In order
1160 to allow earlier responses to still be accepted after these
1161 retransmissions, U-Boot's BOOTP client keeps a small cache of
1162 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1163 cache. The default is to keep IDs for up to four outstanding
1164 requests. Increasing this will allow U-Boot to accept offers
1165 from a BOOTP client in networks with unusually high latency.
1167 - DHCP Advanced Options:
1169 - Link-local IP address negotiation:
1170 Negotiate with other link-local clients on the local network
1171 for an address that doesn't require explicit configuration.
1172 This is especially useful if a DHCP server cannot be guaranteed
1173 to exist in all environments that the device must operate.
1175 See doc/README.link-local for more information.
1177 - MAC address from environment variables
1179 FDT_SEQ_MACADDR_FROM_ENV
1181 Fix-up device tree with MAC addresses fetched sequentially from
1182 environment variables. This config work on assumption that
1183 non-usable ethernet node of device-tree are either not present
1184 or their status has been marked as "disabled".
1187 CONFIG_CDP_DEVICE_ID
1189 The device id used in CDP trigger frames.
1191 CONFIG_CDP_DEVICE_ID_PREFIX
1193 A two character string which is prefixed to the MAC address
1198 A printf format string which contains the ascii name of
1199 the port. Normally is set to "eth%d" which sets
1200 eth0 for the first Ethernet, eth1 for the second etc.
1202 CONFIG_CDP_CAPABILITIES
1204 A 32bit integer which indicates the device capabilities;
1205 0x00000010 for a normal host which does not forwards.
1209 An ascii string containing the version of the software.
1213 An ascii string containing the name of the platform.
1217 A 32bit integer sent on the trigger.
1219 CONFIG_CDP_POWER_CONSUMPTION
1221 A 16bit integer containing the power consumption of the
1222 device in .1 of milliwatts.
1224 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1226 A byte containing the id of the VLAN.
1228 - Status LED: CONFIG_LED_STATUS
1230 Several configurations allow to display the current
1231 status using a LED. For instance, the LED will blink
1232 fast while running U-Boot code, stop blinking as
1233 soon as a reply to a BOOTP request was received, and
1234 start blinking slow once the Linux kernel is running
1235 (supported by a status LED driver in the Linux
1236 kernel). Defining CONFIG_LED_STATUS enables this
1241 CONFIG_LED_STATUS_GPIO
1242 The status LED can be connected to a GPIO pin.
1243 In such cases, the gpio_led driver can be used as a
1244 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1245 to include the gpio_led driver in the U-Boot binary.
1247 CONFIG_GPIO_LED_INVERTED_TABLE
1248 Some GPIO connected LEDs may have inverted polarity in which
1249 case the GPIO high value corresponds to LED off state and
1250 GPIO low value corresponds to LED on state.
1251 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
1252 with a list of GPIO LEDs that have inverted polarity.
1255 CONFIG_SYS_NUM_I2C_BUSES
1256 Hold the number of i2c buses you want to use.
1258 CONFIG_SYS_I2C_DIRECT_BUS
1259 define this, if you don't use i2c muxes on your hardware.
1260 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
1263 CONFIG_SYS_I2C_MAX_HOPS
1264 define how many muxes are maximal consecutively connected
1265 on one i2c bus. If you not use i2c muxes, omit this
1268 CONFIG_SYS_I2C_BUSES
1269 hold a list of buses you want to use, only used if
1270 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
1271 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
1272 CONFIG_SYS_NUM_I2C_BUSES = 9:
1274 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
1275 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
1276 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
1277 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
1278 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
1279 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
1280 {1, {I2C_NULL_HOP}}, \
1281 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
1282 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
1286 bus 0 on adapter 0 without a mux
1287 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
1288 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
1289 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
1290 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
1291 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
1292 bus 6 on adapter 1 without a mux
1293 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
1294 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
1296 If you do not have i2c muxes on your board, omit this define.
1298 - Legacy I2C Support:
1299 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
1300 then the following macros need to be defined (examples are
1301 from include/configs/lwmon.h):
1305 (Optional). Any commands necessary to enable the I2C
1306 controller or configure ports.
1308 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1312 The code necessary to make the I2C data line active
1313 (driven). If the data line is open collector, this
1316 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1320 The code necessary to make the I2C data line tri-stated
1321 (inactive). If the data line is open collector, this
1324 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1328 Code that returns true if the I2C data line is high,
1331 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1335 If <bit> is true, sets the I2C data line high. If it
1336 is false, it clears it (low).
1338 eg: #define I2C_SDA(bit) \
1339 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1340 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1344 If <bit> is true, sets the I2C clock line high. If it
1345 is false, it clears it (low).
1347 eg: #define I2C_SCL(bit) \
1348 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1349 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1353 This delay is invoked four times per clock cycle so this
1354 controls the rate of data transfer. The data rate thus
1355 is 1 / (I2C_DELAY * 4). Often defined to be something
1358 #define I2C_DELAY udelay(2)
1360 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1362 If your arch supports the generic GPIO framework (asm/gpio.h),
1363 then you may alternatively define the two GPIOs that are to be
1364 used as SCL / SDA. Any of the previous I2C_xxx macros will
1365 have GPIO-based defaults assigned to them as appropriate.
1367 You should define these to the GPIO value as given directly to
1368 the generic GPIO functions.
1370 CONFIG_SYS_I2C_INIT_BOARD
1372 When a board is reset during an i2c bus transfer
1373 chips might think that the current transfer is still
1374 in progress. On some boards it is possible to access
1375 the i2c SCLK line directly, either by using the
1376 processor pin as a GPIO or by having a second pin
1377 connected to the bus. If this option is defined a
1378 custom i2c_init_board() routine in boards/xxx/board.c
1379 is run early in the boot sequence.
1381 CONFIG_I2C_MULTI_BUS
1383 This option allows the use of multiple I2C buses, each of which
1384 must have a controller. At any point in time, only one bus is
1385 active. To switch to a different bus, use the 'i2c dev' command.
1386 Note that bus numbering is zero-based.
1388 CONFIG_SYS_I2C_NOPROBES
1390 This option specifies a list of I2C devices that will be skipped
1391 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1392 is set, specify a list of bus-device pairs. Otherwise, specify
1393 a 1D array of device addresses
1396 #undef CONFIG_I2C_MULTI_BUS
1397 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1399 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1401 #define CONFIG_I2C_MULTI_BUS
1402 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1404 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1406 CONFIG_SYS_SPD_BUS_NUM
1408 If defined, then this indicates the I2C bus number for DDR SPD.
1409 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1411 CONFIG_SYS_RTC_BUS_NUM
1413 If defined, then this indicates the I2C bus number for the RTC.
1414 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1416 CONFIG_SOFT_I2C_READ_REPEATED_START
1418 defining this will force the i2c_read() function in
1419 the soft_i2c driver to perform an I2C repeated start
1420 between writing the address pointer and reading the
1421 data. If this define is omitted the default behaviour
1422 of doing a stop-start sequence will be used. Most I2C
1423 devices can use either method, but some require one or
1426 - SPI Support: CONFIG_SPI
1428 Enables SPI driver (so far only tested with
1429 SPI EEPROM, also an instance works with Crystal A/D and
1430 D/As on the SACSng board)
1432 CONFIG_SYS_SPI_MXC_WAIT
1433 Timeout for waiting until spi transfer completed.
1434 default: (CONFIG_SYS_HZ/100) /* 10 ms */
1436 - FPGA Support: CONFIG_FPGA
1438 Enables FPGA subsystem.
1440 CONFIG_FPGA_<vendor>
1442 Enables support for specific chip vendors.
1445 CONFIG_FPGA_<family>
1447 Enables support for FPGA family.
1448 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1452 Specify the number of FPGA devices to support.
1454 CONFIG_SYS_FPGA_PROG_FEEDBACK
1456 Enable printing of hash marks during FPGA configuration.
1458 CONFIG_SYS_FPGA_CHECK_BUSY
1460 Enable checks on FPGA configuration interface busy
1461 status by the configuration function. This option
1462 will require a board or device specific function to
1467 If defined, a function that provides delays in the FPGA
1468 configuration driver.
1470 CONFIG_SYS_FPGA_CHECK_CTRLC
1471 Allow Control-C to interrupt FPGA configuration
1473 CONFIG_SYS_FPGA_CHECK_ERROR
1475 Check for configuration errors during FPGA bitfile
1476 loading. For example, abort during Virtex II
1477 configuration if the INIT_B line goes low (which
1478 indicated a CRC error).
1480 CONFIG_SYS_FPGA_WAIT_INIT
1482 Maximum time to wait for the INIT_B line to de-assert
1483 after PROB_B has been de-asserted during a Virtex II
1484 FPGA configuration sequence. The default time is 500
1487 CONFIG_SYS_FPGA_WAIT_BUSY
1489 Maximum time to wait for BUSY to de-assert during
1490 Virtex II FPGA configuration. The default is 5 ms.
1492 CONFIG_SYS_FPGA_WAIT_CONFIG
1494 Time to wait after FPGA configuration. The default is
1497 - Vendor Parameter Protection:
1499 U-Boot considers the values of the environment
1500 variables "serial#" (Board Serial Number) and
1501 "ethaddr" (Ethernet Address) to be parameters that
1502 are set once by the board vendor / manufacturer, and
1503 protects these variables from casual modification by
1504 the user. Once set, these variables are read-only,
1505 and write or delete attempts are rejected. You can
1506 change this behaviour:
1508 If CONFIG_ENV_OVERWRITE is #defined in your config
1509 file, the write protection for vendor parameters is
1510 completely disabled. Anybody can change or delete
1513 Alternatively, if you define _both_ an ethaddr in the
1514 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1515 Ethernet address is installed in the environment,
1516 which can be changed exactly ONCE by the user. [The
1517 serial# is unaffected by this, i. e. it remains
1520 The same can be accomplished in a more flexible way
1521 for any variable by configuring the type of access
1522 to allow for those variables in the ".flags" variable
1523 or define CONFIG_ENV_FLAGS_LIST_STATIC.
1528 Define this variable to enable the reservation of
1529 "protected RAM", i. e. RAM which is not overwritten
1530 by U-Boot. Define CONFIG_PRAM to hold the number of
1531 kB you want to reserve for pRAM. You can overwrite
1532 this default value by defining an environment
1533 variable "pram" to the number of kB you want to
1534 reserve. Note that the board info structure will
1535 still show the full amount of RAM. If pRAM is
1536 reserved, a new environment variable "mem" will
1537 automatically be defined to hold the amount of
1538 remaining RAM in a form that can be passed as boot
1539 argument to Linux, for instance like that:
1541 setenv bootargs ... mem=\${mem}
1544 This way you can tell Linux not to use this memory,
1545 either, which results in a memory region that will
1546 not be affected by reboots.
1548 *WARNING* If your board configuration uses automatic
1549 detection of the RAM size, you must make sure that
1550 this memory test is non-destructive. So far, the
1551 following board configurations are known to be
1554 IVMS8, IVML24, SPD8xx,
1555 HERMES, IP860, RPXlite, LWMON,
1559 CONFIG_NET_RETRY_COUNT
1561 This variable defines the number of retries for
1562 network operations like ARP, RARP, TFTP, or BOOTP
1563 before giving up the operation. If not defined, a
1564 default value of 5 is used.
1568 Timeout waiting for an ARP reply in milliseconds.
1572 Timeout in milliseconds used in NFS protocol.
1573 If you encounter "ERROR: Cannot umount" in nfs command,
1574 try longer timeout such as
1575 #define CONFIG_NFS_TIMEOUT 10000UL
1579 In the current implementation, the local variables
1580 space and global environment variables space are
1581 separated. Local variables are those you define by
1582 simply typing `name=value'. To access a local
1583 variable later on, you have write `$name' or
1584 `${name}'; to execute the contents of a variable
1585 directly type `$name' at the command prompt.
1587 Global environment variables are those you use
1588 setenv/printenv to work with. To run a command stored
1589 in such a variable, you need to use the run command,
1590 and you must not use the '$' sign to access them.
1592 To store commands and special characters in a
1593 variable, please use double quotation marks
1594 surrounding the whole text of the variable, instead
1595 of the backslashes before semicolons and special
1598 - Command Line Editing and History:
1599 CONFIG_CMDLINE_PS_SUPPORT
1601 Enable support for changing the command prompt string
1602 at run-time. Only static string is supported so far.
1603 The string is obtained from environment variables PS1
1606 - Default Environment:
1607 CONFIG_EXTRA_ENV_SETTINGS
1609 Define this to contain any number of null terminated
1610 strings (variable = value pairs) that will be part of
1611 the default environment compiled into the boot image.
1613 For example, place something like this in your
1614 board's config file:
1616 #define CONFIG_EXTRA_ENV_SETTINGS \
1620 Warning: This method is based on knowledge about the
1621 internal format how the environment is stored by the
1622 U-Boot code. This is NOT an official, exported
1623 interface! Although it is unlikely that this format
1624 will change soon, there is no guarantee either.
1625 You better know what you are doing here.
1627 Note: overly (ab)use of the default environment is
1628 discouraged. Make sure to check other ways to preset
1629 the environment like the "source" command or the
1632 CONFIG_DELAY_ENVIRONMENT
1634 Normally the environment is loaded when the board is
1635 initialised so that it is available to U-Boot. This inhibits
1636 that so that the environment is not available until
1637 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
1638 this is instead controlled by the value of
1639 /config/load-environment.
1641 - TFTP Fixed UDP Port:
1644 If this is defined, the environment variable tftpsrcp
1645 is used to supply the TFTP UDP source port value.
1646 If tftpsrcp isn't defined, the normal pseudo-random port
1647 number generator is used.
1649 Also, the environment variable tftpdstp is used to supply
1650 the TFTP UDP destination port value. If tftpdstp isn't
1651 defined, the normal port 69 is used.
1653 The purpose for tftpsrcp is to allow a TFTP server to
1654 blindly start the TFTP transfer using the pre-configured
1655 target IP address and UDP port. This has the effect of
1656 "punching through" the (Windows XP) firewall, allowing
1657 the remainder of the TFTP transfer to proceed normally.
1658 A better solution is to properly configure the firewall,
1659 but sometimes that is not allowed.
1661 CONFIG_STANDALONE_LOAD_ADDR
1663 This option defines a board specific value for the
1664 address where standalone program gets loaded, thus
1665 overwriting the architecture dependent default
1668 - Frame Buffer Address:
1671 Define CONFIG_FB_ADDR if you want to use specific
1672 address for frame buffer. This is typically the case
1673 when using a graphics controller has separate video
1674 memory. U-Boot will then place the frame buffer at
1675 the given address instead of dynamically reserving it
1676 in system RAM by calling lcd_setmem(), which grabs
1677 the memory for the frame buffer depending on the
1678 configured panel size.
1680 Please see board_init_f function.
1682 - Automatic software updates via TFTP server
1684 CONFIG_UPDATE_TFTP_CNT_MAX
1685 CONFIG_UPDATE_TFTP_MSEC_MAX
1687 These options enable and control the auto-update feature;
1688 for a more detailed description refer to doc/README.update.
1690 - MTD Support (mtdparts command, UBI support)
1691 CONFIG_MTD_UBI_WL_THRESHOLD
1692 This parameter defines the maximum difference between the highest
1693 erase counter value and the lowest erase counter value of eraseblocks
1694 of UBI devices. When this threshold is exceeded, UBI starts performing
1695 wear leveling by means of moving data from eraseblock with low erase
1696 counter to eraseblocks with high erase counter.
1698 The default value should be OK for SLC NAND flashes, NOR flashes and
1699 other flashes which have eraseblock life-cycle 100000 or more.
1700 However, in case of MLC NAND flashes which typically have eraseblock
1701 life-cycle less than 10000, the threshold should be lessened (e.g.,
1702 to 128 or 256, although it does not have to be power of 2).
1706 CONFIG_MTD_UBI_BEB_LIMIT
1707 This option specifies the maximum bad physical eraseblocks UBI
1708 expects on the MTD device (per 1024 eraseblocks). If the
1709 underlying flash does not admit of bad eraseblocks (e.g. NOR
1710 flash), this value is ignored.
1712 NAND datasheets often specify the minimum and maximum NVM
1713 (Number of Valid Blocks) for the flashes' endurance lifetime.
1714 The maximum expected bad eraseblocks per 1024 eraseblocks
1715 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
1716 which gives 20 for most NANDs (MaxNVB is basically the total
1717 count of eraseblocks on the chip).
1719 To put it differently, if this value is 20, UBI will try to
1720 reserve about 1.9% of physical eraseblocks for bad blocks
1721 handling. And that will be 1.9% of eraseblocks on the entire
1722 NAND chip, not just the MTD partition UBI attaches. This means
1723 that if you have, say, a NAND flash chip admits maximum 40 bad
1724 eraseblocks, and it is split on two MTD partitions of the same
1725 size, UBI will reserve 40 eraseblocks when attaching a
1730 CONFIG_MTD_UBI_FASTMAP
1731 Fastmap is a mechanism which allows attaching an UBI device
1732 in nearly constant time. Instead of scanning the whole MTD device it
1733 only has to locate a checkpoint (called fastmap) on the device.
1734 The on-flash fastmap contains all information needed to attach
1735 the device. Using fastmap makes only sense on large devices where
1736 attaching by scanning takes long. UBI will not automatically install
1737 a fastmap on old images, but you can set the UBI parameter
1738 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
1739 that fastmap-enabled images are still usable with UBI implementations
1740 without fastmap support. On typical flash devices the whole fastmap
1741 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
1743 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
1744 Set this parameter to enable fastmap automatically on images
1748 CONFIG_MTD_UBI_FM_DEBUG
1749 Enable UBI fastmap debug
1754 Enable building of SPL globally.
1756 CONFIG_SPL_MAX_FOOTPRINT
1757 Maximum size in memory allocated to the SPL, BSS included.
1758 When defined, the linker checks that the actual memory
1759 used by SPL from _start to __bss_end does not exceed it.
1760 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
1761 must not be both defined at the same time.
1764 Maximum size of the SPL image (text, data, rodata, and
1765 linker lists sections), BSS excluded.
1766 When defined, the linker checks that the actual size does
1769 CONFIG_SPL_RELOC_TEXT_BASE
1770 Address to relocate to. If unspecified, this is equal to
1771 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
1773 CONFIG_SPL_BSS_START_ADDR
1774 Link address for the BSS within the SPL binary.
1776 CONFIG_SPL_BSS_MAX_SIZE
1777 Maximum size in memory allocated to the SPL BSS.
1778 When defined, the linker checks that the actual memory used
1779 by SPL from __bss_start to __bss_end does not exceed it.
1780 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
1781 must not be both defined at the same time.
1784 Adress of the start of the stack SPL will use
1786 CONFIG_SPL_PANIC_ON_RAW_IMAGE
1787 When defined, SPL will panic() if the image it has
1788 loaded does not have a signature.
1789 Defining this is useful when code which loads images
1790 in SPL cannot guarantee that absolutely all read errors
1792 An example is the LPC32XX MLC NAND driver, which will
1793 consider that a completely unreadable NAND block is bad,
1794 and thus should be skipped silently.
1796 CONFIG_SPL_RELOC_STACK
1797 Adress of the start of the stack SPL will use after
1798 relocation. If unspecified, this is equal to
1801 CONFIG_SYS_SPL_MALLOC_START
1802 Starting address of the malloc pool used in SPL.
1803 When this option is set the full malloc is used in SPL and
1804 it is set up by spl_init() and before that, the simple malloc()
1805 can be used if CONFIG_SYS_MALLOC_F is defined.
1807 CONFIG_SYS_SPL_MALLOC_SIZE
1808 The size of the malloc pool used in SPL.
1810 CONFIG_SPL_DISPLAY_PRINT
1811 For ARM, enable an optional function to print more information
1812 about the running system.
1814 CONFIG_SPL_INIT_MINIMAL
1815 Arch init code should be built for a very small image
1817 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
1818 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
1819 Sector and number of sectors to load kernel argument
1820 parameters from when MMC is being used in raw mode
1823 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
1824 Filename to read to load U-Boot when reading from filesystem
1826 CONFIG_SPL_FS_LOAD_KERNEL_NAME
1827 Filename to read to load kernel uImage when reading
1828 from filesystem (for Falcon mode)
1830 CONFIG_SPL_FS_LOAD_ARGS_NAME
1831 Filename to read to load kernel argument parameters
1832 when reading from filesystem (for Falcon mode)
1834 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
1835 Set this for NAND SPL on PPC mpc83xx targets, so that
1836 start.S waits for the rest of the SPL to load before
1837 continuing (the hardware starts execution after just
1838 loading the first page rather than the full 4K).
1840 CONFIG_SPL_SKIP_RELOCATE
1841 Avoid SPL relocation
1844 Support for a lightweight UBI (fastmap) scanner and
1847 CONFIG_SPL_NAND_RAW_ONLY
1848 Support to boot only raw u-boot.bin images. Use this only
1849 if you need to save space.
1851 CONFIG_SPL_COMMON_INIT_DDR
1852 Set for common ddr init with serial presence detect in
1855 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
1856 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
1857 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
1858 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
1859 CONFIG_SYS_NAND_ECCBYTES
1860 Defines the size and behavior of the NAND that SPL uses
1863 CONFIG_SYS_NAND_U_BOOT_DST
1864 Location in memory to load U-Boot to
1866 CONFIG_SYS_NAND_U_BOOT_SIZE
1867 Size of image to load
1869 CONFIG_SYS_NAND_U_BOOT_START
1870 Entry point in loaded image to jump to
1872 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
1873 Define this if you need to first read the OOB and then the
1874 data. This is used, for example, on davinci platforms.
1876 CONFIG_SPL_RAM_DEVICE
1877 Support for running image already present in ram, in SPL binary
1880 Image offset to which the SPL should be padded before appending
1881 the SPL payload. By default, this is defined as
1882 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
1883 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
1884 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
1887 Final target image containing SPL and payload. Some SPLs
1888 use an arch-specific makefile fragment instead, for
1889 example if more than one image needs to be produced.
1891 CONFIG_SPL_FIT_PRINT
1892 Printing information about a FIT image adds quite a bit of
1893 code to SPL. So this is normally disabled in SPL. Use this
1894 option to re-enable it. This will affect the output of the
1895 bootm command when booting a FIT image.
1899 Enable building of TPL globally.
1902 Image offset to which the TPL should be padded before appending
1903 the TPL payload. By default, this is defined as
1904 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
1905 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
1906 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
1908 - Interrupt support (PPC):
1910 There are common interrupt_init() and timer_interrupt()
1911 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1912 for CPU specific initialization. interrupt_init_cpu()
1913 should set decrementer_count to appropriate value. If
1914 CPU resets decrementer automatically after interrupt
1915 (ppc4xx) it should set decrementer_count to zero.
1916 timer_interrupt() calls timer_interrupt_cpu() for CPU
1917 specific handling. If board has watchdog / status_led
1918 / other_activity_monitor it works automatically from
1919 general timer_interrupt().
1922 Board initialization settings:
1923 ------------------------------
1925 During Initialization u-boot calls a number of board specific functions
1926 to allow the preparation of board specific prerequisites, e.g. pin setup
1927 before drivers are initialized. To enable these callbacks the
1928 following configuration macros have to be defined. Currently this is
1929 architecture specific, so please check arch/your_architecture/lib/board.c
1930 typically in board_init_f() and board_init_r().
1932 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
1933 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
1934 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
1936 Configuration Settings:
1937 -----------------------
1939 - MEM_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
1940 Optionally it can be defined to support 64-bit memory commands.
1942 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
1943 undefine this when you're short of memory.
1945 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
1946 width of the commands listed in the 'help' command output.
1948 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
1949 prompt for user input.
1951 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
1953 - CONFIG_SYS_PBSIZE: Buffer size for Console output
1955 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
1957 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
1958 the application (usually a Linux kernel) when it is
1961 - CONFIG_SYS_BAUDRATE_TABLE:
1962 List of legal baudrate settings for this board.
1964 - CONFIG_SYS_MEM_RESERVE_SECURE
1965 Only implemented for ARMv8 for now.
1966 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
1967 is substracted from total RAM and won't be reported to OS.
1968 This memory can be used as secure memory. A variable
1969 gd->arch.secure_ram is used to track the location. In systems
1970 the RAM base is not zero, or RAM is divided into banks,
1971 this variable needs to be recalcuated to get the address.
1973 - CONFIG_SYS_MEM_TOP_HIDE:
1974 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
1975 this specified memory area will get subtracted from the top
1976 (end) of RAM and won't get "touched" at all by U-Boot. By
1977 fixing up gd->ram_size the Linux kernel should gets passed
1978 the now "corrected" memory size and won't touch it either.
1979 This should work for arch/ppc and arch/powerpc. Only Linux
1980 board ports in arch/powerpc with bootwrapper support that
1981 recalculate the memory size from the SDRAM controller setup
1982 will have to get fixed in Linux additionally.
1984 This option can be used as a workaround for the 440EPx/GRx
1985 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
1988 WARNING: Please make sure that this value is a multiple of
1989 the Linux page size (normally 4k). If this is not the case,
1990 then the end address of the Linux memory will be located at a
1991 non page size aligned address and this could cause major
1994 - CONFIG_SYS_LOADS_BAUD_CHANGE:
1995 Enable temporary baudrate change while serial download
1997 - CONFIG_SYS_SDRAM_BASE:
1998 Physical start address of SDRAM. _Must_ be 0 here.
2000 - CONFIG_SYS_FLASH_BASE:
2001 Physical start address of Flash memory.
2003 - CONFIG_SYS_MONITOR_BASE:
2004 Physical start address of boot monitor code (set by
2005 make config files to be same as the text base address
2006 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2007 CONFIG_SYS_FLASH_BASE when booting from flash.
2009 - CONFIG_SYS_MONITOR_LEN:
2010 Size of memory reserved for monitor code, used to
2011 determine _at_compile_time_ (!) if the environment is
2012 embedded within the U-Boot image, or in a separate
2015 - CONFIG_SYS_MALLOC_LEN:
2016 Size of DRAM reserved for malloc() use.
2018 - CONFIG_SYS_MALLOC_F_LEN
2019 Size of the malloc() pool for use before relocation. If
2020 this is defined, then a very simple malloc() implementation
2021 will become available before relocation. The address is just
2022 below the global data, and the stack is moved down to make
2025 This feature allocates regions with increasing addresses
2026 within the region. calloc() is supported, but realloc()
2027 is not available. free() is supported but does nothing.
2028 The memory will be freed (or in fact just forgotten) when
2029 U-Boot relocates itself.
2031 - CONFIG_SYS_MALLOC_SIMPLE
2032 Provides a simple and small malloc() and calloc() for those
2033 boards which do not use the full malloc in SPL (which is
2034 enabled with CONFIG_SYS_SPL_MALLOC_START).
2036 - CONFIG_SYS_NONCACHED_MEMORY:
2037 Size of non-cached memory area. This area of memory will be
2038 typically located right below the malloc() area and mapped
2039 uncached in the MMU. This is useful for drivers that would
2040 otherwise require a lot of explicit cache maintenance. For
2041 some drivers it's also impossible to properly maintain the
2042 cache. For example if the regions that need to be flushed
2043 are not a multiple of the cache-line size, *and* padding
2044 cannot be allocated between the regions to align them (i.e.
2045 if the HW requires a contiguous array of regions, and the
2046 size of each region is not cache-aligned), then a flush of
2047 one region may result in overwriting data that hardware has
2048 written to another region in the same cache-line. This can
2049 happen for example in network drivers where descriptors for
2050 buffers are typically smaller than the CPU cache-line (e.g.
2051 16 bytes vs. 32 or 64 bytes).
2053 Non-cached memory is only supported on 32-bit ARM at present.
2055 - CONFIG_SYS_BOOTM_LEN:
2056 Normally compressed uImages are limited to an
2057 uncompressed size of 8 MBytes. If this is not enough,
2058 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2059 to adjust this setting to your needs.
2061 - CONFIG_SYS_BOOTMAPSZ:
2062 Maximum size of memory mapped by the startup code of
2063 the Linux kernel; all data that must be processed by
2064 the Linux kernel (bd_info, boot arguments, FDT blob if
2065 used) must be put below this limit, unless "bootm_low"
2066 environment variable is defined and non-zero. In such case
2067 all data for the Linux kernel must be between "bootm_low"
2068 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2069 variable "bootm_mapsize" will override the value of
2070 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2071 then the value in "bootm_size" will be used instead.
2073 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2074 Enable initrd_high functionality. If defined then the
2075 initrd_high feature is enabled and the bootm ramdisk subcommand
2078 - CONFIG_SYS_BOOT_GET_CMDLINE:
2079 Enables allocating and saving kernel cmdline in space between
2080 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2082 - CONFIG_SYS_BOOT_GET_KBD:
2083 Enables allocating and saving a kernel copy of the bd_info in
2084 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2086 - CONFIG_SYS_MAX_FLASH_SECT:
2087 Max number of sectors on a Flash chip
2089 - CONFIG_SYS_FLASH_ERASE_TOUT:
2090 Timeout for Flash erase operations (in ms)
2092 - CONFIG_SYS_FLASH_WRITE_TOUT:
2093 Timeout for Flash write operations (in ms)
2095 - CONFIG_SYS_FLASH_LOCK_TOUT
2096 Timeout for Flash set sector lock bit operation (in ms)
2098 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2099 Timeout for Flash clear lock bits operation (in ms)
2101 - CONFIG_SYS_FLASH_PROTECTION
2102 If defined, hardware flash sectors protection is used
2103 instead of U-Boot software protection.
2105 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2107 Enable TFTP transfers directly to flash memory;
2108 without this option such a download has to be
2109 performed in two steps: (1) download to RAM, and (2)
2110 copy from RAM to flash.
2112 The two-step approach is usually more reliable, since
2113 you can check if the download worked before you erase
2114 the flash, but in some situations (when system RAM is
2115 too limited to allow for a temporary copy of the
2116 downloaded image) this option may be very useful.
2118 - CONFIG_SYS_FLASH_CFI:
2119 Define if the flash driver uses extra elements in the
2120 common flash structure for storing flash geometry.
2122 - CONFIG_FLASH_CFI_DRIVER
2123 This option also enables the building of the cfi_flash driver
2124 in the drivers directory
2126 - CONFIG_FLASH_CFI_MTD
2127 This option enables the building of the cfi_mtd driver
2128 in the drivers directory. The driver exports CFI flash
2131 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2132 Use buffered writes to flash.
2134 - CONFIG_FLASH_SPANSION_S29WS_N
2135 s29ws-n MirrorBit flash has non-standard addresses for buffered
2138 - CONFIG_SYS_FLASH_QUIET_TEST
2139 If this option is defined, the common CFI flash doesn't
2140 print it's warning upon not recognized FLASH banks. This
2141 is useful, if some of the configured banks are only
2142 optionally available.
2144 - CONFIG_FLASH_SHOW_PROGRESS
2145 If defined (must be an integer), print out countdown
2146 digits and dots. Recommended value: 45 (9..1) for 80
2147 column displays, 15 (3..1) for 40 column displays.
2149 - CONFIG_FLASH_VERIFY
2150 If defined, the content of the flash (destination) is compared
2151 against the source after the write operation. An error message
2152 will be printed when the contents are not identical.
2153 Please note that this option is useless in nearly all cases,
2154 since such flash programming errors usually are detected earlier
2155 while unprotecting/erasing/programming. Please only enable
2156 this option if you really know what you are doing.
2158 - CONFIG_SYS_RX_ETH_BUFFER:
2159 Defines the number of Ethernet receive buffers. On some
2160 Ethernet controllers it is recommended to set this value
2161 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2162 buffers can be full shortly after enabling the interface
2163 on high Ethernet traffic.
2164 Defaults to 4 if not defined.
2166 - CONFIG_ENV_MAX_ENTRIES
2168 Maximum number of entries in the hash table that is used
2169 internally to store the environment settings. The default
2170 setting is supposed to be generous and should work in most
2171 cases. This setting can be used to tune behaviour; see
2172 lib/hashtable.c for details.
2174 - CONFIG_ENV_FLAGS_LIST_DEFAULT
2175 - CONFIG_ENV_FLAGS_LIST_STATIC
2176 Enable validation of the values given to environment variables when
2177 calling env set. Variables can be restricted to only decimal,
2178 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
2179 the variables can also be restricted to IP address or MAC address.
2181 The format of the list is:
2182 type_attribute = [s|d|x|b|i|m]
2183 access_attribute = [a|r|o|c]
2184 attributes = type_attribute[access_attribute]
2185 entry = variable_name[:attributes]
2188 The type attributes are:
2189 s - String (default)
2192 b - Boolean ([1yYtT|0nNfF])
2196 The access attributes are:
2202 - CONFIG_ENV_FLAGS_LIST_DEFAULT
2203 Define this to a list (string) to define the ".flags"
2204 environment variable in the default or embedded environment.
2206 - CONFIG_ENV_FLAGS_LIST_STATIC
2207 Define this to a list (string) to define validation that
2208 should be done if an entry is not found in the ".flags"
2209 environment variable. To override a setting in the static
2210 list, simply add an entry for the same variable name to the
2213 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
2214 regular expression. This allows multiple variables to define the same
2215 flags without explicitly listing them for each variable.
2217 The following definitions that deal with the placement and management
2218 of environment data (variable area); in general, we support the
2219 following configurations:
2221 - CONFIG_BUILD_ENVCRC:
2223 Builds up envcrc with the target environment so that external utils
2224 may easily extract it and embed it in final U-Boot images.
2226 BE CAREFUL! The first access to the environment happens quite early
2227 in U-Boot initialization (when we try to get the setting of for the
2228 console baudrate). You *MUST* have mapped your NVRAM area then, or
2231 Please note that even with NVRAM we still use a copy of the
2232 environment in RAM: we could work on NVRAM directly, but we want to
2233 keep settings there always unmodified except somebody uses "saveenv"
2234 to save the current settings.
2236 BE CAREFUL! For some special cases, the local device can not use
2237 "saveenv" command. For example, the local device will get the
2238 environment stored in a remote NOR flash by SRIO or PCIE link,
2239 but it can not erase, write this NOR flash by SRIO or PCIE interface.
2241 - CONFIG_NAND_ENV_DST
2243 Defines address in RAM to which the nand_spl code should copy the
2244 environment. If redundant environment is used, it will be copied to
2245 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
2247 Please note that the environment is read-only until the monitor
2248 has been relocated to RAM and a RAM copy of the environment has been
2249 created; also, when using EEPROM you will have to use env_get_f()
2250 until then to read environment variables.
2252 The environment is protected by a CRC32 checksum. Before the monitor
2253 is relocated into RAM, as a result of a bad CRC you will be working
2254 with the compiled-in default environment - *silently*!!! [This is
2255 necessary, because the first environment variable we need is the
2256 "baudrate" setting for the console - if we have a bad CRC, we don't
2257 have any device yet where we could complain.]
2259 Note: once the monitor has been relocated, then it will complain if
2260 the default environment is used; a new CRC is computed as soon as you
2261 use the "saveenv" command to store a valid environment.
2263 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
2264 Echo the inverted Ethernet link state to the fault LED.
2266 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
2267 also needs to be defined.
2269 - CONFIG_SYS_FAULT_MII_ADDR:
2270 MII address of the PHY to check for the Ethernet link state.
2272 - CONFIG_NS16550_MIN_FUNCTIONS:
2273 Define this if you desire to only have use of the NS16550_init
2274 and NS16550_putc functions for the serial driver located at
2275 drivers/serial/ns16550.c. This option is useful for saving
2276 space for already greatly restricted images, including but not
2277 limited to NAND_SPL configurations.
2279 - CONFIG_DISPLAY_BOARDINFO
2280 Display information about the board that U-Boot is running on
2281 when U-Boot starts up. The board function checkboard() is called
2284 - CONFIG_DISPLAY_BOARDINFO_LATE
2285 Similar to the previous option, but display this information
2286 later, once stdio is running and output goes to the LCD, if
2289 - CONFIG_BOARD_SIZE_LIMIT:
2290 Maximum size of the U-Boot image. When defined, the
2291 build system checks that the actual size does not
2294 Low Level (hardware related) configuration options:
2295 ---------------------------------------------------
2297 - CONFIG_SYS_CACHELINE_SIZE:
2298 Cache Line Size of the CPU.
2300 - CONFIG_SYS_CCSRBAR_DEFAULT:
2301 Default (power-on reset) physical address of CCSR on Freescale
2304 - CONFIG_SYS_CCSRBAR:
2305 Virtual address of CCSR. On a 32-bit build, this is typically
2306 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
2308 - CONFIG_SYS_CCSRBAR_PHYS:
2309 Physical address of CCSR. CCSR can be relocated to a new
2310 physical address, if desired. In this case, this macro should
2311 be set to that address. Otherwise, it should be set to the
2312 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
2313 is typically relocated on 36-bit builds. It is recommended
2314 that this macro be defined via the _HIGH and _LOW macros:
2316 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
2317 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
2319 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
2320 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
2321 either 0 (32-bit build) or 0xF (36-bit build). This macro is
2322 used in assembly code, so it must not contain typecasts or
2323 integer size suffixes (e.g. "ULL").
2325 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
2326 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
2327 used in assembly code, so it must not contain typecasts or
2328 integer size suffixes (e.g. "ULL").
2330 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
2331 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
2332 forced to a value that ensures that CCSR is not relocated.
2334 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
2335 DO NOT CHANGE unless you know exactly what you're
2336 doing! (11-4) [MPC8xx systems only]
2338 - CONFIG_SYS_INIT_RAM_ADDR:
2340 Start address of memory area that can be used for
2341 initial data and stack; please note that this must be
2342 writable memory that is working WITHOUT special
2343 initialization, i. e. you CANNOT use normal RAM which
2344 will become available only after programming the
2345 memory controller and running certain initialization
2348 U-Boot uses the following memory types:
2349 - MPC8xx: IMMR (internal memory of the CPU)
2351 - CONFIG_SYS_GBL_DATA_OFFSET:
2353 Offset of the initial data structure in the memory
2354 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
2355 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
2356 data is located at the end of the available space
2357 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
2358 GENERATED_GBL_DATA_SIZE), and the initial stack is just
2359 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
2360 CONFIG_SYS_GBL_DATA_OFFSET) downward.
2363 On the MPC824X (or other systems that use the data
2364 cache for initial memory) the address chosen for
2365 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
2366 point to an otherwise UNUSED address space between
2367 the top of RAM and the start of the PCI space.
2369 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
2371 - CONFIG_SYS_OR_TIMING_SDRAM:
2374 - CONFIG_SYS_MAMR_PTA:
2375 periodic timer for refresh
2378 Chip has SRIO or not
2381 Board has SRIO 1 port available
2384 Board has SRIO 2 port available
2386 - CONFIG_SRIO_PCIE_BOOT_MASTER
2387 Board can support master function for Boot from SRIO and PCIE
2389 - CONFIG_SYS_SRIOn_MEM_VIRT:
2390 Virtual Address of SRIO port 'n' memory region
2392 - CONFIG_SYS_SRIOn_MEM_PHYxS:
2393 Physical Address of SRIO port 'n' memory region
2395 - CONFIG_SYS_SRIOn_MEM_SIZE:
2396 Size of SRIO port 'n' memory region
2398 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
2399 Defined to tell the NAND controller that the NAND chip is using
2401 Not all NAND drivers use this symbol.
2402 Example of drivers that use it:
2403 - drivers/mtd/nand/raw/ndfc.c
2404 - drivers/mtd/nand/raw/mxc_nand.c
2406 - CONFIG_SYS_NDFC_EBC0_CFG
2407 Sets the EBC0_CFG register for the NDFC. If not defined
2408 a default value will be used.
2411 Get DDR timing information from an I2C EEPROM. Common
2412 with pluggable memory modules such as SODIMMs
2415 I2C address of the SPD EEPROM
2417 - CONFIG_SYS_SPD_BUS_NUM
2418 If SPD EEPROM is on an I2C bus other than the first
2419 one, specify here. Note that the value must resolve
2420 to something your driver can deal with.
2422 - CONFIG_SYS_DDR_RAW_TIMING
2423 Get DDR timing information from other than SPD. Common with
2424 soldered DDR chips onboard without SPD. DDR raw timing
2425 parameters are extracted from datasheet and hard-coded into
2426 header files or board specific files.
2428 - CONFIG_FSL_DDR_INTERACTIVE
2429 Enable interactive DDR debugging. See doc/README.fsl-ddr.
2431 - CONFIG_FSL_DDR_SYNC_REFRESH
2432 Enable sync of refresh for multiple controllers.
2434 - CONFIG_FSL_DDR_BIST
2435 Enable built-in memory test for Freescale DDR controllers.
2437 - CONFIG_SYS_83XX_DDR_USES_CS0
2438 Only for 83xx systems. If specified, then DDR should
2439 be configured using CS0 and CS1 instead of CS2 and CS3.
2442 Enable RMII mode for all FECs.
2443 Note that this is a global option, we can't
2444 have one FEC in standard MII mode and another in RMII mode.
2446 - CONFIG_CRC32_VERIFY
2447 Add a verify option to the crc32 command.
2450 => crc32 -v <address> <count> <crc32>
2452 Where address/count indicate a memory area
2453 and crc32 is the correct crc32 which the
2457 Add the "loopw" memory command. This only takes effect if
2458 the memory commands are activated globally (CONFIG_CMD_MEMORY).
2460 - CONFIG_CMD_MX_CYCLIC
2461 Add the "mdc" and "mwc" memory commands. These are cyclic
2466 This command will print 4 bytes (10,11,12,13) each 500 ms.
2468 => mwc.l 100 12345678 10
2469 This command will write 12345678 to address 100 all 10 ms.
2471 This only takes effect if the memory commands are activated
2472 globally (CONFIG_CMD_MEMORY).
2475 Set when the currently-running compilation is for an artifact
2476 that will end up in the SPL (as opposed to the TPL or U-Boot
2477 proper). Code that needs stage-specific behavior should check
2481 Set when the currently-running compilation is for an artifact
2482 that will end up in the TPL (as opposed to the SPL or U-Boot
2483 proper). Code that needs stage-specific behavior should check
2486 - CONFIG_SYS_MPC85XX_NO_RESETVEC
2487 Only for 85xx systems. If this variable is specified, the section
2488 .resetvec is not kept and the section .bootpg is placed in the
2489 previous 4k of the .text section.
2491 - CONFIG_ARCH_MAP_SYSMEM
2492 Generally U-Boot (and in particular the md command) uses
2493 effective address. It is therefore not necessary to regard
2494 U-Boot address as virtual addresses that need to be translated
2495 to physical addresses. However, sandbox requires this, since
2496 it maintains its own little RAM buffer which contains all
2497 addressable memory. This option causes some memory accesses
2498 to be mapped through map_sysmem() / unmap_sysmem().
2500 - CONFIG_X86_RESET_VECTOR
2501 If defined, the x86 reset vector code is included. This is not
2502 needed when U-Boot is running from Coreboot.
2504 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
2505 Option to disable subpage write in NAND driver
2506 driver that uses this:
2507 drivers/mtd/nand/raw/davinci_nand.c
2509 Freescale QE/FMAN Firmware Support:
2510 -----------------------------------
2512 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
2513 loading of "firmware", which is encoded in the QE firmware binary format.
2514 This firmware often needs to be loaded during U-Boot booting, so macros
2515 are used to identify the storage device (NOR flash, SPI, etc) and the address
2518 - CONFIG_SYS_FMAN_FW_ADDR
2519 The address in the storage device where the FMAN microcode is located. The
2520 meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro
2523 - CONFIG_SYS_QE_FW_ADDR
2524 The address in the storage device where the QE microcode is located. The
2525 meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro
2528 - CONFIG_SYS_QE_FMAN_FW_LENGTH
2529 The maximum possible size of the firmware. The firmware binary format
2530 has a field that specifies the actual size of the firmware, but it
2531 might not be possible to read any part of the firmware unless some
2532 local storage is allocated to hold the entire firmware first.
2534 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
2535 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
2536 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
2537 virtual address in NOR flash.
2539 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
2540 Specifies that QE/FMAN firmware is located in NAND flash.
2541 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
2543 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
2544 Specifies that QE/FMAN firmware is located on the primary SD/MMC
2545 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
2547 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
2548 Specifies that QE/FMAN firmware is located in the remote (master)
2549 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
2550 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
2551 window->master inbound window->master LAW->the ucode address in
2552 master's memory space.
2554 Freescale Layerscape Management Complex Firmware Support:
2555 ---------------------------------------------------------
2556 The Freescale Layerscape Management Complex (MC) supports the loading of
2558 This firmware often needs to be loaded during U-Boot booting, so macros
2559 are used to identify the storage device (NOR flash, SPI, etc) and the address
2562 - CONFIG_FSL_MC_ENET
2563 Enable the MC driver for Layerscape SoCs.
2565 Freescale Layerscape Debug Server Support:
2566 -------------------------------------------
2567 The Freescale Layerscape Debug Server Support supports the loading of
2568 "Debug Server firmware" and triggering SP boot-rom.
2569 This firmware often needs to be loaded during U-Boot booting.
2571 - CONFIG_SYS_MC_RSV_MEM_ALIGN
2572 Define alignment of reserved memory MC requires
2577 In order to achieve reproducible builds, timestamps used in the U-Boot build
2578 process have to be set to a fixed value.
2580 This is done using the SOURCE_DATE_EPOCH environment variable.
2581 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
2582 option for U-Boot or an environment variable in U-Boot.
2584 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
2586 Building the Software:
2587 ======================
2589 Building U-Boot has been tested in several native build environments
2590 and in many different cross environments. Of course we cannot support
2591 all possibly existing versions of cross development tools in all
2592 (potentially obsolete) versions. In case of tool chain problems we
2593 recommend to use the ELDK (see https://www.denx.de/wiki/DULG/ELDK)
2594 which is extensively used to build and test U-Boot.
2596 If you are not using a native environment, it is assumed that you
2597 have GNU cross compiling tools available in your path. In this case,
2598 you must set the environment variable CROSS_COMPILE in your shell.
2599 Note that no changes to the Makefile or any other source files are
2600 necessary. For example using the ELDK on a 4xx CPU, please enter:
2602 $ CROSS_COMPILE=ppc_4xx-
2603 $ export CROSS_COMPILE
2605 U-Boot is intended to be simple to build. After installing the
2606 sources you must configure U-Boot for one specific board type. This
2611 where "NAME_defconfig" is the name of one of the existing configu-
2612 rations; see configs/*_defconfig for supported names.
2614 Note: for some boards special configuration names may exist; check if
2615 additional information is available from the board vendor; for
2616 instance, the TQM823L systems are available without (standard)
2617 or with LCD support. You can select such additional "features"
2618 when choosing the configuration, i. e.
2620 make TQM823L_defconfig
2621 - will configure for a plain TQM823L, i. e. no LCD support
2623 make TQM823L_LCD_defconfig
2624 - will configure for a TQM823L with U-Boot console on LCD
2629 Finally, type "make all", and you should get some working U-Boot
2630 images ready for download to / installation on your system:
2632 - "u-boot.bin" is a raw binary image
2633 - "u-boot" is an image in ELF binary format
2634 - "u-boot.srec" is in Motorola S-Record format
2636 By default the build is performed locally and the objects are saved
2637 in the source directory. One of the two methods can be used to change
2638 this behavior and build U-Boot to some external directory:
2640 1. Add O= to the make command line invocations:
2642 make O=/tmp/build distclean
2643 make O=/tmp/build NAME_defconfig
2644 make O=/tmp/build all
2646 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
2648 export KBUILD_OUTPUT=/tmp/build
2653 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
2656 User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by
2657 setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS.
2658 For example to treat all compiler warnings as errors:
2660 make KCFLAGS=-Werror
2662 Please be aware that the Makefiles assume you are using GNU make, so
2663 for instance on NetBSD you might need to use "gmake" instead of
2667 If the system board that you have is not listed, then you will need
2668 to port U-Boot to your hardware platform. To do this, follow these
2671 1. Create a new directory to hold your board specific code. Add any
2672 files you need. In your board directory, you will need at least
2673 the "Makefile" and a "<board>.c".
2674 2. Create a new configuration file "include/configs/<board>.h" for
2676 3. If you're porting U-Boot to a new CPU, then also create a new
2677 directory to hold your CPU specific code. Add any files you need.
2678 4. Run "make <board>_defconfig" with your new name.
2679 5. Type "make", and you should get a working "u-boot.srec" file
2680 to be installed on your target system.
2681 6. Debug and solve any problems that might arise.
2682 [Of course, this last step is much harder than it sounds.]
2685 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2686 ==============================================================
2688 If you have modified U-Boot sources (for instance added a new board
2689 or support for new devices, a new CPU, etc.) you are expected to
2690 provide feedback to the other developers. The feedback normally takes
2691 the form of a "patch", i.e. a context diff against a certain (latest
2692 official or latest in the git repository) version of U-Boot sources.
2694 But before you submit such a patch, please verify that your modifi-
2695 cation did not break existing code. At least make sure that *ALL* of
2696 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2697 just run the buildman script (tools/buildman/buildman), which will
2698 configure and build U-Boot for ALL supported system. Be warned, this
2699 will take a while. Please see the buildman README, or run 'buildman -H'
2703 See also "U-Boot Porting Guide" below.
2706 Monitor Commands - Overview:
2707 ============================
2709 go - start application at address 'addr'
2710 run - run commands in an environment variable
2711 bootm - boot application image from memory
2712 bootp - boot image via network using BootP/TFTP protocol
2713 bootz - boot zImage from memory
2714 tftpboot- boot image via network using TFTP protocol
2715 and env variables "ipaddr" and "serverip"
2716 (and eventually "gatewayip")
2717 tftpput - upload a file via network using TFTP protocol
2718 rarpboot- boot image via network using RARP/TFTP protocol
2719 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2720 loads - load S-Record file over serial line
2721 loadb - load binary file over serial line (kermit mode)
2723 mm - memory modify (auto-incrementing)
2724 nm - memory modify (constant address)
2725 mw - memory write (fill)
2728 cmp - memory compare
2729 crc32 - checksum calculation
2730 i2c - I2C sub-system
2731 sspi - SPI utility commands
2732 base - print or set address offset
2733 printenv- print environment variables
2734 pwm - control pwm channels
2735 setenv - set environment variables
2736 saveenv - save environment variables to persistent storage
2737 protect - enable or disable FLASH write protection
2738 erase - erase FLASH memory
2739 flinfo - print FLASH memory information
2740 nand - NAND memory operations (see doc/README.nand)
2741 bdinfo - print Board Info structure
2742 iminfo - print header information for application image
2743 coninfo - print console devices and informations
2744 ide - IDE sub-system
2745 loop - infinite loop on address range
2746 loopw - infinite write loop on address range
2747 mtest - simple RAM test
2748 icache - enable or disable instruction cache
2749 dcache - enable or disable data cache
2750 reset - Perform RESET of the CPU
2751 echo - echo args to console
2752 version - print monitor version
2753 help - print online help
2754 ? - alias for 'help'
2757 Monitor Commands - Detailed Description:
2758 ========================================
2762 For now: just type "help <command>".
2765 Note for Redundant Ethernet Interfaces:
2766 =======================================
2768 Some boards come with redundant Ethernet interfaces; U-Boot supports
2769 such configurations and is capable of automatic selection of a
2770 "working" interface when needed. MAC assignment works as follows:
2772 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2773 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2774 "eth1addr" (=>eth1), "eth2addr", ...
2776 If the network interface stores some valid MAC address (for instance
2777 in SROM), this is used as default address if there is NO correspon-
2778 ding setting in the environment; if the corresponding environment
2779 variable is set, this overrides the settings in the card; that means:
2781 o If the SROM has a valid MAC address, and there is no address in the
2782 environment, the SROM's address is used.
2784 o If there is no valid address in the SROM, and a definition in the
2785 environment exists, then the value from the environment variable is
2788 o If both the SROM and the environment contain a MAC address, and
2789 both addresses are the same, this MAC address is used.
2791 o If both the SROM and the environment contain a MAC address, and the
2792 addresses differ, the value from the environment is used and a
2795 o If neither SROM nor the environment contain a MAC address, an error
2796 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
2797 a random, locally-assigned MAC is used.
2799 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
2800 will be programmed into hardware as part of the initialization process. This
2801 may be skipped by setting the appropriate 'ethmacskip' environment variable.
2802 The naming convention is as follows:
2803 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
2808 U-Boot is capable of booting (and performing other auxiliary operations on)
2809 images in two formats:
2811 New uImage format (FIT)
2812 -----------------------
2814 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
2815 to Flattened Device Tree). It allows the use of images with multiple
2816 components (several kernels, ramdisks, etc.), with contents protected by
2817 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
2823 Old image format is based on binary files which can be basically anything,
2824 preceded by a special header; see the definitions in include/image.h for
2825 details; basically, the header defines the following image properties:
2827 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2828 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2829 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
2830 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, INTEGRITY).
2831 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2832 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2833 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC).
2834 * Compression Type (uncompressed, gzip, bzip2)
2840 The header is marked by a special Magic Number, and both the header
2841 and the data portions of the image are secured against corruption by
2848 Although U-Boot should support any OS or standalone application
2849 easily, the main focus has always been on Linux during the design of
2852 U-Boot includes many features that so far have been part of some
2853 special "boot loader" code within the Linux kernel. Also, any
2854 "initrd" images to be used are no longer part of one big Linux image;
2855 instead, kernel and "initrd" are separate images. This implementation
2856 serves several purposes:
2858 - the same features can be used for other OS or standalone
2859 applications (for instance: using compressed images to reduce the
2860 Flash memory footprint)
2862 - it becomes much easier to port new Linux kernel versions because
2863 lots of low-level, hardware dependent stuff are done by U-Boot
2865 - the same Linux kernel image can now be used with different "initrd"
2866 images; of course this also means that different kernel images can
2867 be run with the same "initrd". This makes testing easier (you don't
2868 have to build a new "zImage.initrd" Linux image when you just
2869 change a file in your "initrd"). Also, a field-upgrade of the
2870 software is easier now.
2876 Porting Linux to U-Boot based systems:
2877 ---------------------------------------
2879 U-Boot cannot save you from doing all the necessary modifications to
2880 configure the Linux device drivers for use with your target hardware
2881 (no, we don't intend to provide a full virtual machine interface to
2884 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
2886 Just make sure your machine specific header file (for instance
2887 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2888 Information structure as we define in include/asm-<arch>/u-boot.h,
2889 and make sure that your definition of IMAP_ADDR uses the same value
2890 as your U-Boot configuration in CONFIG_SYS_IMMR.
2892 Note that U-Boot now has a driver model, a unified model for drivers.
2893 If you are adding a new driver, plumb it into driver model. If there
2894 is no uclass available, you are encouraged to create one. See
2898 Configuring the Linux kernel:
2899 -----------------------------
2901 No specific requirements for U-Boot. Make sure you have some root
2902 device (initial ramdisk, NFS) for your target system.
2905 Building a Linux Image:
2906 -----------------------
2908 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2909 not used. If you use recent kernel source, a new build target
2910 "uImage" will exist which automatically builds an image usable by
2911 U-Boot. Most older kernels also have support for a "pImage" target,
2912 which was introduced for our predecessor project PPCBoot and uses a
2913 100% compatible format.
2917 make TQM850L_defconfig
2922 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2923 encapsulate a compressed Linux kernel image with header information,
2924 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2926 * build a standard "vmlinux" kernel image (in ELF binary format):
2928 * convert the kernel into a raw binary image:
2930 ${CROSS_COMPILE}-objcopy -O binary \
2931 -R .note -R .comment \
2932 -S vmlinux linux.bin
2934 * compress the binary image:
2938 * package compressed binary image for U-Boot:
2940 mkimage -A ppc -O linux -T kernel -C gzip \
2941 -a 0 -e 0 -n "Linux Kernel Image" \
2942 -d linux.bin.gz uImage
2945 The "mkimage" tool can also be used to create ramdisk images for use
2946 with U-Boot, either separated from the Linux kernel image, or
2947 combined into one file. "mkimage" encapsulates the images with a 64
2948 byte header containing information about target architecture,
2949 operating system, image type, compression method, entry points, time
2950 stamp, CRC32 checksums, etc.
2952 "mkimage" can be called in two ways: to verify existing images and
2953 print the header information, or to build new images.
2955 In the first form (with "-l" option) mkimage lists the information
2956 contained in the header of an existing U-Boot image; this includes
2957 checksum verification:
2959 tools/mkimage -l image
2960 -l ==> list image header information
2962 The second form (with "-d" option) is used to build a U-Boot image
2963 from a "data file" which is used as image payload:
2965 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2966 -n name -d data_file image
2967 -A ==> set architecture to 'arch'
2968 -O ==> set operating system to 'os'
2969 -T ==> set image type to 'type'
2970 -C ==> set compression type 'comp'
2971 -a ==> set load address to 'addr' (hex)
2972 -e ==> set entry point to 'ep' (hex)
2973 -n ==> set image name to 'name'
2974 -d ==> use image data from 'datafile'
2976 Right now, all Linux kernels for PowerPC systems use the same load
2977 address (0x00000000), but the entry point address depends on the
2980 - 2.2.x kernels have the entry point at 0x0000000C,
2981 - 2.3.x and later kernels have the entry point at 0x00000000.
2983 So a typical call to build a U-Boot image would read:
2985 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2986 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2987 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
2988 > examples/uImage.TQM850L
2989 Image Name: 2.4.4 kernel for TQM850L
2990 Created: Wed Jul 19 02:34:59 2000
2991 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2992 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2993 Load Address: 0x00000000
2994 Entry Point: 0x00000000
2996 To verify the contents of the image (or check for corruption):
2998 -> tools/mkimage -l examples/uImage.TQM850L
2999 Image Name: 2.4.4 kernel for TQM850L
3000 Created: Wed Jul 19 02:34:59 2000
3001 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3002 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3003 Load Address: 0x00000000
3004 Entry Point: 0x00000000
3006 NOTE: for embedded systems where boot time is critical you can trade
3007 speed for memory and install an UNCOMPRESSED image instead: this
3008 needs more space in Flash, but boots much faster since it does not
3009 need to be uncompressed:
3011 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
3012 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3013 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3014 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
3015 > examples/uImage.TQM850L-uncompressed
3016 Image Name: 2.4.4 kernel for TQM850L
3017 Created: Wed Jul 19 02:34:59 2000
3018 Image Type: PowerPC Linux Kernel Image (uncompressed)
3019 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3020 Load Address: 0x00000000
3021 Entry Point: 0x00000000
3024 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3025 when your kernel is intended to use an initial ramdisk:
3027 -> tools/mkimage -n 'Simple Ramdisk Image' \
3028 > -A ppc -O linux -T ramdisk -C gzip \
3029 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3030 Image Name: Simple Ramdisk Image
3031 Created: Wed Jan 12 14:01:50 2000
3032 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3033 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3034 Load Address: 0x00000000
3035 Entry Point: 0x00000000
3037 The "dumpimage" tool can be used to disassemble or list the contents of images
3038 built by mkimage. See dumpimage's help output (-h) for details.
3040 Installing a Linux Image:
3041 -------------------------
3043 To downloading a U-Boot image over the serial (console) interface,
3044 you must convert the image to S-Record format:
3046 objcopy -I binary -O srec examples/image examples/image.srec
3048 The 'objcopy' does not understand the information in the U-Boot
3049 image header, so the resulting S-Record file will be relative to
3050 address 0x00000000. To load it to a given address, you need to
3051 specify the target address as 'offset' parameter with the 'loads'
3054 Example: install the image to address 0x40100000 (which on the
3055 TQM8xxL is in the first Flash bank):
3057 => erase 40100000 401FFFFF
3063 ## Ready for S-Record download ...
3064 ~>examples/image.srec
3065 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3067 15989 15990 15991 15992
3068 [file transfer complete]
3070 ## Start Addr = 0x00000000
3073 You can check the success of the download using the 'iminfo' command;
3074 this includes a checksum verification so you can be sure no data
3075 corruption happened:
3079 ## Checking Image at 40100000 ...
3080 Image Name: 2.2.13 for initrd on TQM850L
3081 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3082 Data Size: 335725 Bytes = 327 kB = 0 MB
3083 Load Address: 00000000
3084 Entry Point: 0000000c
3085 Verifying Checksum ... OK
3091 The "bootm" command is used to boot an application that is stored in
3092 memory (RAM or Flash). In case of a Linux kernel image, the contents
3093 of the "bootargs" environment variable is passed to the kernel as
3094 parameters. You can check and modify this variable using the
3095 "printenv" and "setenv" commands:
3098 => printenv bootargs
3099 bootargs=root=/dev/ram
3101 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3103 => printenv bootargs
3104 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3107 ## Booting Linux kernel at 40020000 ...
3108 Image Name: 2.2.13 for NFS on TQM850L
3109 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3110 Data Size: 381681 Bytes = 372 kB = 0 MB
3111 Load Address: 00000000
3112 Entry Point: 0000000c
3113 Verifying Checksum ... OK
3114 Uncompressing Kernel Image ... OK
3115 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
3116 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3117 time_init: decrementer frequency = 187500000/60
3118 Calibrating delay loop... 49.77 BogoMIPS
3119 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3122 If you want to boot a Linux kernel with initial RAM disk, you pass
3123 the memory addresses of both the kernel and the initrd image (PPBCOOT
3124 format!) to the "bootm" command:
3126 => imi 40100000 40200000
3128 ## Checking Image at 40100000 ...
3129 Image Name: 2.2.13 for initrd on TQM850L
3130 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3131 Data Size: 335725 Bytes = 327 kB = 0 MB
3132 Load Address: 00000000
3133 Entry Point: 0000000c
3134 Verifying Checksum ... OK
3136 ## Checking Image at 40200000 ...
3137 Image Name: Simple Ramdisk Image
3138 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3139 Data Size: 566530 Bytes = 553 kB = 0 MB
3140 Load Address: 00000000
3141 Entry Point: 00000000
3142 Verifying Checksum ... OK
3144 => bootm 40100000 40200000
3145 ## Booting Linux kernel at 40100000 ...
3146 Image Name: 2.2.13 for initrd on TQM850L
3147 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3148 Data Size: 335725 Bytes = 327 kB = 0 MB
3149 Load Address: 00000000
3150 Entry Point: 0000000c
3151 Verifying Checksum ... OK
3152 Uncompressing Kernel Image ... OK
3153 ## Loading RAMDisk Image at 40200000 ...
3154 Image Name: Simple Ramdisk Image
3155 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3156 Data Size: 566530 Bytes = 553 kB = 0 MB
3157 Load Address: 00000000
3158 Entry Point: 00000000
3159 Verifying Checksum ... OK
3160 Loading Ramdisk ... OK
3161 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
3162 Boot arguments: root=/dev/ram
3163 time_init: decrementer frequency = 187500000/60
3164 Calibrating delay loop... 49.77 BogoMIPS
3166 RAMDISK: Compressed image found at block 0
3167 VFS: Mounted root (ext2 filesystem).
3171 Boot Linux and pass a flat device tree:
3174 First, U-Boot must be compiled with the appropriate defines. See the section
3175 titled "Linux Kernel Interface" above for a more in depth explanation. The
3176 following is an example of how to start a kernel and pass an updated
3182 oft=oftrees/mpc8540ads.dtb
3183 => tftp $oftaddr $oft
3184 Speed: 1000, full duplex
3186 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3187 Filename 'oftrees/mpc8540ads.dtb'.
3188 Load address: 0x300000
3191 Bytes transferred = 4106 (100a hex)
3192 => tftp $loadaddr $bootfile
3193 Speed: 1000, full duplex
3195 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3197 Load address: 0x200000
3198 Loading:############
3200 Bytes transferred = 1029407 (fb51f hex)
3205 => bootm $loadaddr - $oftaddr
3206 ## Booting image at 00200000 ...
3207 Image Name: Linux-2.6.17-dirty
3208 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3209 Data Size: 1029343 Bytes = 1005.2 kB
3210 Load Address: 00000000
3211 Entry Point: 00000000
3212 Verifying Checksum ... OK
3213 Uncompressing Kernel Image ... OK
3214 Booting using flat device tree at 0x300000
3215 Using MPC85xx ADS machine description
3216 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3220 More About U-Boot Image Types:
3221 ------------------------------
3223 U-Boot supports the following image types:
3225 "Standalone Programs" are directly runnable in the environment
3226 provided by U-Boot; it is expected that (if they behave
3227 well) you can continue to work in U-Boot after return from
3228 the Standalone Program.
3229 "OS Kernel Images" are usually images of some Embedded OS which
3230 will take over control completely. Usually these programs
3231 will install their own set of exception handlers, device
3232 drivers, set up the MMU, etc. - this means, that you cannot
3233 expect to re-enter U-Boot except by resetting the CPU.
3234 "RAMDisk Images" are more or less just data blocks, and their
3235 parameters (address, size) are passed to an OS kernel that is
3237 "Multi-File Images" contain several images, typically an OS
3238 (Linux) kernel image and one or more data images like
3239 RAMDisks. This construct is useful for instance when you want
3240 to boot over the network using BOOTP etc., where the boot
3241 server provides just a single image file, but you want to get
3242 for instance an OS kernel and a RAMDisk image.
3244 "Multi-File Images" start with a list of image sizes, each
3245 image size (in bytes) specified by an "uint32_t" in network
3246 byte order. This list is terminated by an "(uint32_t)0".
3247 Immediately after the terminating 0 follow the images, one by
3248 one, all aligned on "uint32_t" boundaries (size rounded up to
3249 a multiple of 4 bytes).
3251 "Firmware Images" are binary images containing firmware (like
3252 U-Boot or FPGA images) which usually will be programmed to
3255 "Script files" are command sequences that will be executed by
3256 U-Boot's command interpreter; this feature is especially
3257 useful when you configure U-Boot to use a real shell (hush)
3258 as command interpreter.
3260 Booting the Linux zImage:
3261 -------------------------
3263 On some platforms, it's possible to boot Linux zImage. This is done
3264 using the "bootz" command. The syntax of "bootz" command is the same
3265 as the syntax of "bootm" command.
3267 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
3268 kernel with raw initrd images. The syntax is slightly different, the
3269 address of the initrd must be augmented by it's size, in the following
3270 format: "<initrd addres>:<initrd size>".
3276 One of the features of U-Boot is that you can dynamically load and
3277 run "standalone" applications, which can use some resources of
3278 U-Boot like console I/O functions or interrupt services.
3280 Two simple examples are included with the sources:
3285 'examples/hello_world.c' contains a small "Hello World" Demo
3286 application; it is automatically compiled when you build U-Boot.
3287 It's configured to run at address 0x00040004, so you can play with it
3291 ## Ready for S-Record download ...
3292 ~>examples/hello_world.srec
3293 1 2 3 4 5 6 7 8 9 10 11 ...
3294 [file transfer complete]
3296 ## Start Addr = 0x00040004
3298 => go 40004 Hello World! This is a test.
3299 ## Starting application at 0x00040004 ...
3310 Hit any key to exit ...
3312 ## Application terminated, rc = 0x0
3314 Another example, which demonstrates how to register a CPM interrupt
3315 handler with the U-Boot code, can be found in 'examples/timer.c'.
3316 Here, a CPM timer is set up to generate an interrupt every second.
3317 The interrupt service routine is trivial, just printing a '.'
3318 character, but this is just a demo program. The application can be
3319 controlled by the following keys:
3321 ? - print current values og the CPM Timer registers
3322 b - enable interrupts and start timer
3323 e - stop timer and disable interrupts
3324 q - quit application
3327 ## Ready for S-Record download ...
3328 ~>examples/timer.srec
3329 1 2 3 4 5 6 7 8 9 10 11 ...
3330 [file transfer complete]
3332 ## Start Addr = 0x00040004
3335 ## Starting application at 0x00040004 ...
3338 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3341 [q, b, e, ?] Set interval 1000000 us
3344 [q, b, e, ?] ........
3345 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3348 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3351 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3354 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3356 [q, b, e, ?] ...Stopping timer
3358 [q, b, e, ?] ## Application terminated, rc = 0x0
3364 Over time, many people have reported problems when trying to use the
3365 "minicom" terminal emulation program for serial download. I (wd)
3366 consider minicom to be broken, and recommend not to use it. Under
3367 Unix, I recommend to use C-Kermit for general purpose use (and
3368 especially for kermit binary protocol download ("loadb" command), and
3369 use "cu" for S-Record download ("loads" command). See
3370 https://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
3371 for help with kermit.
3374 Nevertheless, if you absolutely want to use it try adding this
3375 configuration to your "File transfer protocols" section:
3377 Name Program Name U/D FullScr IO-Red. Multi
3378 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3379 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3385 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3386 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3388 Building requires a cross environment; it is known to work on
3389 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3390 need gmake since the Makefiles are not compatible with BSD make).
3391 Note that the cross-powerpc package does not install include files;
3392 attempting to build U-Boot will fail because <machine/ansi.h> is
3393 missing. This file has to be installed and patched manually:
3395 # cd /usr/pkg/cross/powerpc-netbsd/include
3397 # ln -s powerpc machine
3398 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3399 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3401 Native builds *don't* work due to incompatibilities between native
3402 and U-Boot include files.
3404 Booting assumes that (the first part of) the image booted is a
3405 stage-2 loader which in turn loads and then invokes the kernel
3406 proper. Loader sources will eventually appear in the NetBSD source
3407 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3408 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3411 Implementation Internals:
3412 =========================
3414 The following is not intended to be a complete description of every
3415 implementation detail. However, it should help to understand the
3416 inner workings of U-Boot and make it easier to port it to custom
3420 Initial Stack, Global Data:
3421 ---------------------------
3423 The implementation of U-Boot is complicated by the fact that U-Boot
3424 starts running out of ROM (flash memory), usually without access to
3425 system RAM (because the memory controller is not initialized yet).
3426 This means that we don't have writable Data or BSS segments, and BSS
3427 is not initialized as zero. To be able to get a C environment working
3428 at all, we have to allocate at least a minimal stack. Implementation
3429 options for this are defined and restricted by the CPU used: Some CPU
3430 models provide on-chip memory (like the IMMR area on MPC8xx and
3431 MPC826x processors), on others (parts of) the data cache can be
3432 locked as (mis-) used as memory, etc.
3434 Chris Hallinan posted a good summary of these issues to the
3435 U-Boot mailing list:
3437 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3438 From: "Chris Hallinan" <clh@net1plus.com>
3439 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3442 Correct me if I'm wrong, folks, but the way I understand it
3443 is this: Using DCACHE as initial RAM for Stack, etc, does not
3444 require any physical RAM backing up the cache. The cleverness
3445 is that the cache is being used as a temporary supply of
3446 necessary storage before the SDRAM controller is setup. It's
3447 beyond the scope of this list to explain the details, but you
3448 can see how this works by studying the cache architecture and
3449 operation in the architecture and processor-specific manuals.
3451 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3452 is another option for the system designer to use as an
3453 initial stack/RAM area prior to SDRAM being available. Either
3454 option should work for you. Using CS 4 should be fine if your
3455 board designers haven't used it for something that would
3456 cause you grief during the initial boot! It is frequently not
3459 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
3460 with your processor/board/system design. The default value
3461 you will find in any recent u-boot distribution in
3462 walnut.h should work for you. I'd set it to a value larger
3463 than your SDRAM module. If you have a 64MB SDRAM module, set
3464 it above 400_0000. Just make sure your board has no resources
3465 that are supposed to respond to that address! That code in
3466 start.S has been around a while and should work as is when
3467 you get the config right.
3472 It is essential to remember this, since it has some impact on the C
3473 code for the initialization procedures:
3475 * Initialized global data (data segment) is read-only. Do not attempt
3478 * Do not use any uninitialized global data (or implicitly initialized
3479 as zero data - BSS segment) at all - this is undefined, initiali-
3480 zation is performed later (when relocating to RAM).
3482 * Stack space is very limited. Avoid big data buffers or things like
3485 Having only the stack as writable memory limits means we cannot use
3486 normal global data to share information between the code. But it
3487 turned out that the implementation of U-Boot can be greatly
3488 simplified by making a global data structure (gd_t) available to all
3489 functions. We could pass a pointer to this data as argument to _all_
3490 functions, but this would bloat the code. Instead we use a feature of
3491 the GCC compiler (Global Register Variables) to share the data: we
3492 place a pointer (gd) to the global data into a register which we
3493 reserve for this purpose.
3495 When choosing a register for such a purpose we are restricted by the
3496 relevant (E)ABI specifications for the current architecture, and by
3497 GCC's implementation.
3499 For PowerPC, the following registers have specific use:
3501 R2: reserved for system use
3502 R3-R4: parameter passing and return values
3503 R5-R10: parameter passing
3504 R13: small data area pointer
3508 (U-Boot also uses R12 as internal GOT pointer. r12
3509 is a volatile register so r12 needs to be reset when
3510 going back and forth between asm and C)
3512 ==> U-Boot will use R2 to hold a pointer to the global data
3514 Note: on PPC, we could use a static initializer (since the
3515 address of the global data structure is known at compile time),
3516 but it turned out that reserving a register results in somewhat
3517 smaller code - although the code savings are not that big (on
3518 average for all boards 752 bytes for the whole U-Boot image,
3519 624 text + 127 data).
3521 On ARM, the following registers are used:
3523 R0: function argument word/integer result
3524 R1-R3: function argument word
3525 R9: platform specific
3526 R10: stack limit (used only if stack checking is enabled)
3527 R11: argument (frame) pointer
3528 R12: temporary workspace
3531 R15: program counter
3533 ==> U-Boot will use R9 to hold a pointer to the global data
3535 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
3537 On Nios II, the ABI is documented here:
3538 https://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
3540 ==> U-Boot will use gp to hold a pointer to the global data
3542 Note: on Nios II, we give "-G0" option to gcc and don't use gp
3543 to access small data sections, so gp is free.
3545 On NDS32, the following registers are used:
3547 R0-R1: argument/return
3549 R15: temporary register for assembler
3550 R16: trampoline register
3551 R28: frame pointer (FP)
3552 R29: global pointer (GP)
3553 R30: link register (LP)
3554 R31: stack pointer (SP)
3555 PC: program counter (PC)
3557 ==> U-Boot will use R10 to hold a pointer to the global data
3559 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3560 or current versions of GCC may "optimize" the code too much.
3562 On RISC-V, the following registers are used:
3564 x0: hard-wired zero (zero)
3565 x1: return address (ra)
3566 x2: stack pointer (sp)
3567 x3: global pointer (gp)
3568 x4: thread pointer (tp)
3569 x5: link register (t0)
3570 x8: frame pointer (fp)
3571 x10-x11: arguments/return values (a0-1)
3572 x12-x17: arguments (a2-7)
3573 x28-31: temporaries (t3-6)
3574 pc: program counter (pc)
3576 ==> U-Boot will use gp to hold a pointer to the global data
3581 U-Boot runs in system state and uses physical addresses, i.e. the
3582 MMU is not used either for address mapping nor for memory protection.
3584 The available memory is mapped to fixed addresses using the memory
3585 controller. In this process, a contiguous block is formed for each
3586 memory type (Flash, SDRAM, SRAM), even when it consists of several
3587 physical memory banks.
3589 U-Boot is installed in the first 128 kB of the first Flash bank (on
3590 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3591 booting and sizing and initializing DRAM, the code relocates itself
3592 to the upper end of DRAM. Immediately below the U-Boot code some
3593 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
3594 configuration setting]. Below that, a structure with global Board
3595 Info data is placed, followed by the stack (growing downward).
3597 Additionally, some exception handler code is copied to the low 8 kB
3598 of DRAM (0x00000000 ... 0x00001FFF).
3600 So a typical memory configuration with 16 MB of DRAM could look like
3603 0x0000 0000 Exception Vector code
3606 0x0000 2000 Free for Application Use
3612 0x00FB FF20 Monitor Stack (Growing downward)
3613 0x00FB FFAC Board Info Data and permanent copy of global data
3614 0x00FC 0000 Malloc Arena
3617 0x00FE 0000 RAM Copy of Monitor Code
3618 ... eventually: LCD or video framebuffer
3619 ... eventually: pRAM (Protected RAM - unchanged by reset)
3620 0x00FF FFFF [End of RAM]
3623 System Initialization:
3624 ----------------------
3626 In the reset configuration, U-Boot starts at the reset entry point
3627 (on most PowerPC systems at address 0x00000100). Because of the reset
3628 configuration for CS0# this is a mirror of the on board Flash memory.
3629 To be able to re-map memory U-Boot then jumps to its link address.
3630 To be able to implement the initialization code in C, a (small!)
3631 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3632 which provide such a feature like), or in a locked part of the data
3633 cache. After that, U-Boot initializes the CPU core, the caches and
3636 Next, all (potentially) available memory banks are mapped using a
3637 preliminary mapping. For example, we put them on 512 MB boundaries
3638 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3639 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3640 programmed for SDRAM access. Using the temporary configuration, a
3641 simple memory test is run that determines the size of the SDRAM
3644 When there is more than one SDRAM bank, and the banks are of
3645 different size, the largest is mapped first. For equal size, the first
3646 bank (CS2#) is mapped first. The first mapping is always for address
3647 0x00000000, with any additional banks following immediately to create
3648 contiguous memory starting from 0.
3650 Then, the monitor installs itself at the upper end of the SDRAM area
3651 and allocates memory for use by malloc() and for the global Board
3652 Info data; also, the exception vector code is copied to the low RAM
3653 pages, and the final stack is set up.
3655 Only after this relocation will you have a "normal" C environment;
3656 until that you are restricted in several ways, mostly because you are
3657 running from ROM, and because the code will have to be relocated to a
3661 U-Boot Porting Guide:
3662 ----------------------
3664 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3668 int main(int argc, char *argv[])
3670 sighandler_t no_more_time;
3672 signal(SIGALRM, no_more_time);
3673 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
3675 if (available_money > available_manpower) {
3676 Pay consultant to port U-Boot;
3680 Download latest U-Boot source;
3682 Subscribe to u-boot mailing list;
3685 email("Hi, I am new to U-Boot, how do I get started?");
3688 Read the README file in the top level directory;
3689 Read https://www.denx.de/wiki/bin/view/DULG/Manual;
3690 Read applicable doc/README.*;
3691 Read the source, Luke;
3692 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
3695 if (available_money > toLocalCurrency ($2500))
3698 Add a lot of aggravation and time;
3700 if (a similar board exists) { /* hopefully... */
3701 cp -a board/<similar> board/<myboard>
3702 cp include/configs/<similar>.h include/configs/<myboard>.h
3704 Create your own board support subdirectory;
3705 Create your own board include/configs/<myboard>.h file;
3707 Edit new board/<myboard> files
3708 Edit new include/configs/<myboard>.h
3713 Add / modify source code;
3717 email("Hi, I am having problems...");
3719 Send patch file to the U-Boot email list;
3720 if (reasonable critiques)
3721 Incorporate improvements from email list code review;
3723 Defend code as written;
3729 void no_more_time (int sig)
3738 All contributions to U-Boot should conform to the Linux kernel
3739 coding style; see the kernel coding style guide at
3740 https://www.kernel.org/doc/html/latest/process/coding-style.html, and the
3741 script "scripts/Lindent" in your Linux kernel source directory.
3743 Source files originating from a different project (for example the
3744 MTD subsystem) are generally exempt from these guidelines and are not
3745 reformatted to ease subsequent migration to newer versions of those
3748 Please note that U-Boot is implemented in C (and to some small parts in
3749 Assembler); no C++ is used, so please do not use C++ style comments (//)
3752 Please also stick to the following formatting rules:
3753 - remove any trailing white space
3754 - use TAB characters for indentation and vertical alignment, not spaces
3755 - make sure NOT to use DOS '\r\n' line feeds
3756 - do not add more than 2 consecutive empty lines to source files
3757 - do not add trailing empty lines to source files
3759 Submissions which do not conform to the standards may be returned
3760 with a request to reformat the changes.
3766 Since the number of patches for U-Boot is growing, we need to
3767 establish some rules. Submissions which do not conform to these rules
3768 may be rejected, even when they contain important and valuable stuff.
3770 Please see https://www.denx.de/wiki/U-Boot/Patches for details.
3772 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
3773 see https://lists.denx.de/listinfo/u-boot
3775 When you send a patch, please include the following information with
3778 * For bug fixes: a description of the bug and how your patch fixes
3779 this bug. Please try to include a way of demonstrating that the
3780 patch actually fixes something.
3782 * For new features: a description of the feature and your
3785 * For major contributions, add a MAINTAINERS file with your
3786 information and associated file and directory references.
3788 * When you add support for a new board, don't forget to add a
3789 maintainer e-mail address to the boards.cfg file, too.
3791 * If your patch adds new configuration options, don't forget to
3792 document these in the README file.
3794 * The patch itself. If you are using git (which is *strongly*
3795 recommended) you can easily generate the patch using the
3796 "git format-patch". If you then use "git send-email" to send it to
3797 the U-Boot mailing list, you will avoid most of the common problems
3798 with some other mail clients.
3800 If you cannot use git, use "diff -purN OLD NEW". If your version of
3801 diff does not support these options, then get the latest version of
3804 The current directory when running this command shall be the parent
3805 directory of the U-Boot source tree (i. e. please make sure that
3806 your patch includes sufficient directory information for the
3809 We prefer patches as plain text. MIME attachments are discouraged,
3810 and compressed attachments must not be used.
3812 * If one logical set of modifications affects or creates several
3813 files, all these changes shall be submitted in a SINGLE patch file.
3815 * Changesets that contain different, unrelated modifications shall be
3816 submitted as SEPARATE patches, one patch per changeset.
3821 * Before sending the patch, run the buildman script on your patched
3822 source tree and make sure that no errors or warnings are reported
3823 for any of the boards.
3825 * Keep your modifications to the necessary minimum: A patch
3826 containing several unrelated changes or arbitrary reformats will be
3827 returned with a request to re-formatting / split it.
3829 * If you modify existing code, make sure that your new code does not
3830 add to the memory footprint of the code ;-) Small is beautiful!
3831 When adding new features, these should compile conditionally only
3832 (using #ifdef), and the resulting code with the new feature
3833 disabled must not need more memory than the old code without your
3836 * Remember that there is a size limit of 100 kB per message on the
3837 u-boot mailing list. Bigger patches will be moderated. If they are
3838 reasonable and not too big, they will be acknowledged. But patches
3839 bigger than the size limit should be avoided.