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 /nios2 Files generic to Altera NIOS2 architecture
138 /powerpc Files generic to PowerPC architecture
139 /riscv Files generic to RISC-V architecture
140 /sandbox Files generic to HW-independent "sandbox"
141 /sh Files generic to SH architecture
142 /x86 Files generic to x86 architecture
143 /xtensa Files generic to Xtensa architecture
144 /api Machine/arch-independent API for external apps
145 /board Board-dependent files
146 /boot Support for images and booting
147 /cmd U-Boot commands functions
148 /common Misc architecture-independent functions
149 /configs Board default configuration files
150 /disk Code for disk drive partition handling
151 /doc Documentation (a mix of ReST and READMEs)
152 /drivers Device drivers
153 /dts Makefile for building internal U-Boot fdt.
154 /env Environment support
155 /examples Example code for standalone applications, etc.
156 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
157 /include Header Files
158 /lib Library routines generic to all architectures
159 /Licenses Various license files
161 /post Power On Self Test
162 /scripts Various build scripts and Makefiles
163 /test Various unit test files
164 /tools Tools to build and sign FIT images, etc.
166 Software Configuration:
167 =======================
169 Configuration is usually done using C preprocessor defines; the
170 rationale behind that is to avoid dead code whenever possible.
172 There are two classes of configuration variables:
174 * Configuration _OPTIONS_:
175 These are selectable by the user and have names beginning with
178 * Configuration _SETTINGS_:
179 These depend on the hardware etc. and should not be meddled with if
180 you don't know what you're doing; they have names beginning with
183 Previously, all configuration was done by hand, which involved creating
184 symbolic links and editing configuration files manually. More recently,
185 U-Boot has added the Kbuild infrastructure used by the Linux kernel,
186 allowing you to use the "make menuconfig" command to configure your
190 Selection of Processor Architecture and Board Type:
191 ---------------------------------------------------
193 For all supported boards there are ready-to-use default
194 configurations available; just type "make <board_name>_defconfig".
196 Example: For a TQM823L module type:
199 make TQM823L_defconfig
201 Note: If you're looking for the default configuration file for a board
202 you're sure used to be there but is now missing, check the file
203 doc/README.scrapyard for a list of no longer supported boards.
208 U-Boot can be built natively to run on a Linux host using the 'sandbox'
209 board. This allows feature development which is not board- or architecture-
210 specific to be undertaken on a native platform. The sandbox is also used to
211 run some of U-Boot's tests.
213 See doc/arch/sandbox.rst for more details.
216 Board Initialisation Flow:
217 --------------------------
219 This is the intended start-up flow for boards. This should apply for both
220 SPL and U-Boot proper (i.e. they both follow the same rules).
222 Note: "SPL" stands for "Secondary Program Loader," which is explained in
223 more detail later in this file.
225 At present, SPL mostly uses a separate code path, but the function names
226 and roles of each function are the same. Some boards or architectures
227 may not conform to this. At least most ARM boards which use
228 CONFIG_SPL_FRAMEWORK conform to this.
230 Execution typically starts with an architecture-specific (and possibly
231 CPU-specific) start.S file, such as:
233 - arch/arm/cpu/armv7/start.S
234 - arch/powerpc/cpu/mpc83xx/start.S
235 - arch/mips/cpu/start.S
237 and so on. From there, three functions are called; the purpose and
238 limitations of each of these functions are described below.
241 - purpose: essential init to permit execution to reach board_init_f()
242 - no global_data or BSS
243 - there is no stack (ARMv7 may have one but it will soon be removed)
244 - must not set up SDRAM or use console
245 - must only do the bare minimum to allow execution to continue to
247 - this is almost never needed
248 - return normally from this function
251 - purpose: set up the machine ready for running board_init_r():
252 i.e. SDRAM and serial UART
253 - global_data is available
255 - BSS is not available, so you cannot use global/static variables,
256 only stack variables and global_data
258 Non-SPL-specific notes:
259 - dram_init() is called to set up DRAM. If already done in SPL this
263 - you can override the entire board_init_f() function with your own
265 - preloader_console_init() can be called here in extremis
266 - should set up SDRAM, and anything needed to make the UART work
267 - there is no need to clear BSS, it will be done by crt0.S
268 - for specific scenarios on certain architectures an early BSS *can*
269 be made available (via CONFIG_SPL_EARLY_BSS by moving the clearing
270 of BSS prior to entering board_init_f()) but doing so is discouraged.
271 Instead it is strongly recommended to architect any code changes
272 or additions such to not depend on the availability of BSS during
273 board_init_f() as indicated in other sections of this README to
274 maintain compatibility and consistency across the entire code base.
275 - must return normally from this function (don't call board_init_r()
278 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
279 this point the stack and global_data are relocated to below
280 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
284 - purpose: main execution, common code
285 - global_data is available
287 - BSS is available, all static/global variables can be used
288 - execution eventually continues to main_loop()
290 Non-SPL-specific notes:
291 - U-Boot is relocated to the top of memory and is now running from
295 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
296 CONFIG_SYS_FSL_HAS_CCI400
298 Defined For SoC that has cache coherent interconnect
301 CONFIG_SYS_FSL_HAS_CCN504
303 Defined for SoC that has cache coherent interconnect CCN-504
305 The following options need to be configured:
307 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
309 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
314 Specifies that the core is a 64-bit PowerPC implementation (implements
315 the "64" category of the Power ISA). This is necessary for ePAPR
316 compliance, among other possible reasons.
318 CONFIG_SYS_FSL_TBCLK_DIV
320 Defines the core time base clock divider ratio compared to the
321 system clock. On most PQ3 devices this is 8, on newer QorIQ
322 devices it can be 16 or 32. The ratio varies from SoC to Soc.
324 CONFIG_SYS_FSL_PCIE_COMPAT
326 Defines the string to utilize when trying to match PCIe device
327 tree nodes for the given platform.
329 CONFIG_SYS_FSL_ERRATUM_A004510
331 Enables a workaround for erratum A004510. If set,
332 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
333 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
335 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
336 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
338 Defines one or two SoC revisions (low 8 bits of SVR)
339 for which the A004510 workaround should be applied.
341 The rest of SVR is either not relevant to the decision
342 of whether the erratum is present (e.g. p2040 versus
343 p2041) or is implied by the build target, which controls
344 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
346 See Freescale App Note 4493 for more information about
349 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
351 This is the value to write into CCSR offset 0x18600
352 according to the A004510 workaround.
354 CONFIG_SYS_FSL_DSP_DDR_ADDR
355 This value denotes start offset of DDR memory which is
356 connected exclusively to the DSP cores.
358 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
359 This value denotes start offset of M2 memory
360 which is directly connected to the DSP core.
362 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
363 This value denotes start offset of M3 memory which is directly
364 connected to the DSP core.
366 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
367 This value denotes start offset of DSP CCSR space.
369 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
370 Single Source Clock is clocking mode present in some of FSL SoC's.
371 In this mode, a single differential clock is used to supply
372 clocks to the sysclock, ddrclock and usbclock.
374 - Generic CPU options:
375 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
377 Defines the endianess of the CPU. Implementation of those
378 values is arch specific.
381 Freescale DDR driver in use. This type of DDR controller is
382 found in mpc83xx, mpc85xx as well as some ARM core SoCs.
384 CONFIG_SYS_FSL_DDR_ADDR
385 Freescale DDR memory-mapped register base.
387 CONFIG_SYS_FSL_DDRC_GEN1
388 Freescale DDR1 controller.
390 CONFIG_SYS_FSL_DDRC_GEN2
391 Freescale DDR2 controller.
393 CONFIG_SYS_FSL_DDRC_GEN3
394 Freescale DDR3 controller.
396 CONFIG_SYS_FSL_DDRC_GEN4
397 Freescale DDR4 controller.
399 CONFIG_SYS_FSL_DDRC_ARM_GEN3
400 Freescale DDR3 controller for ARM-based SoCs.
403 Board config to use DDR1. It can be enabled for SoCs with
404 Freescale DDR1 or DDR2 controllers, depending on the board
408 Board config to use DDR2. It can be enabled for SoCs with
409 Freescale DDR2 or DDR3 controllers, depending on the board
413 Board config to use DDR3. It can be enabled for SoCs with
414 Freescale DDR3 or DDR3L controllers.
417 Board config to use DDR3L. It can be enabled for SoCs with
420 CONFIG_SYS_FSL_IFC_BE
421 Defines the IFC controller register space as Big Endian
423 CONFIG_SYS_FSL_IFC_LE
424 Defines the IFC controller register space as Little Endian
426 CONFIG_SYS_FSL_IFC_CLK_DIV
427 Defines divider of platform clock(clock input to IFC controller).
429 CONFIG_SYS_FSL_LBC_CLK_DIV
430 Defines divider of platform clock(clock input to eLBC controller).
432 CONFIG_SYS_FSL_DDR_BE
433 Defines the DDR controller register space as Big Endian
435 CONFIG_SYS_FSL_DDR_LE
436 Defines the DDR controller register space as Little Endian
438 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
439 Physical address from the view of DDR controllers. It is the
440 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
441 it could be different for ARM SoCs.
443 CONFIG_SYS_FSL_DDR_INTLV_256B
444 DDR controller interleaving on 256-byte. This is a special
445 interleaving mode, handled by Dickens for Freescale layerscape
448 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
449 Number of controllers used as main memory.
451 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
452 Number of controllers used for other than main memory.
454 CONFIG_SYS_FSL_SEC_BE
455 Defines the SEC controller register space as Big Endian
457 CONFIG_SYS_FSL_SEC_LE
458 Defines the SEC controller register space as Little Endian
461 CONFIG_XWAY_SWAP_BYTES
463 Enable compilation of tools/xway-swap-bytes needed for Lantiq
464 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
465 be swapped if a flash programmer is used.
468 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
470 Select high exception vectors of the ARM core, e.g., do not
471 clear the V bit of the c1 register of CP15.
474 Generic timer clock source frequency.
476 COUNTER_FREQUENCY_REAL
477 Generic timer clock source frequency if the real clock is
478 different from COUNTER_FREQUENCY, and can only be determined
482 CONFIG_TEGRA_SUPPORT_NON_SECURE
484 Support executing U-Boot in non-secure (NS) mode. Certain
485 impossible actions will be skipped if the CPU is in NS mode,
486 such as ARM architectural timer initialization.
488 - Linux Kernel Interface:
489 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
491 When transferring memsize parameter to Linux, some versions
492 expect it to be in bytes, others in MB.
493 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
497 New kernel versions are expecting firmware settings to be
498 passed using flattened device trees (based on open firmware
502 * New libfdt-based support
503 * Adds the "fdt" command
504 * The bootm command automatically updates the fdt
506 OF_TBCLK - The timebase frequency.
508 boards with QUICC Engines require OF_QE to set UCC MAC
513 U-Boot can detect if an IDE device is present or not.
514 If not, and this new config option is activated, U-Boot
515 removes the ATA node from the DTS before booting Linux,
516 so the Linux IDE driver does not probe the device and
517 crash. This is needed for buggy hardware (uc101) where
518 no pull down resistor is connected to the signal IDE5V_DD7.
520 - vxWorks boot parameters:
522 bootvx constructs a valid bootline using the following
523 environments variables: bootdev, bootfile, ipaddr, netmask,
524 serverip, gatewayip, hostname, othbootargs.
525 It loads the vxWorks image pointed bootfile.
527 Note: If a "bootargs" environment is defined, it will override
528 the defaults discussed just above.
530 - Cache Configuration for ARM:
531 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
533 CONFIG_SYS_PL310_BASE - Physical base address of PL310
534 controller register space
539 If you have Amba PrimeCell PL011 UARTs, set this variable to
540 the clock speed of the UARTs.
544 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
545 define this to a list of base addresses for each (supported)
546 port. See e.g. include/configs/versatile.h
548 CONFIG_SERIAL_HW_FLOW_CONTROL
550 Define this variable to enable hw flow control in serial driver.
551 Current user of this option is drivers/serial/nsl16550.c driver
553 - Serial Download Echo Mode:
555 If defined to 1, all characters received during a
556 serial download (using the "loads" command) are
557 echoed back. This might be needed by some terminal
558 emulations (like "cu"), but may as well just take
559 time on others. This setting #define's the initial
560 value of the "loads_echo" environment variable.
562 - Removal of commands
563 If no commands are needed to boot, you can disable
564 CONFIG_CMDLINE to remove them. In this case, the command line
565 will not be available, and when U-Boot wants to execute the
566 boot command (on start-up) it will call board_run_command()
567 instead. This can reduce image size significantly for very
568 simple boot procedures.
570 - Regular expression support:
572 If this variable is defined, U-Boot is linked against
573 the SLRE (Super Light Regular Expression) library,
574 which adds regex support to some commands, as for
575 example "env grep" and "setexpr".
578 CONFIG_SYS_WATCHDOG_FREQ
579 Some platforms automatically call WATCHDOG_RESET()
580 from the timer interrupt handler every
581 CONFIG_SYS_WATCHDOG_FREQ interrupts. If not set by the
582 board configuration file, a default of CONFIG_SYS_HZ/2
583 (i.e. 500) is used. Setting CONFIG_SYS_WATCHDOG_FREQ
584 to 0 disables calling WATCHDOG_RESET() from the timer
589 When CONFIG_CMD_DATE is selected, the type of the RTC
590 has to be selected, too. Define exactly one of the
593 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
594 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
595 CONFIG_RTC_MC146818 - use MC146818 RTC
596 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
597 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
598 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
599 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
600 CONFIG_RTC_DS164x - use Dallas DS164x RTC
601 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
602 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
603 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
604 CONFIG_SYS_RV3029_TCR - enable trickle charger on
607 Note that if the RTC uses I2C, then the I2C interface
608 must also be configured. See I2C Support, below.
611 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
613 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
614 chip-ngpio pairs that tell the PCA953X driver the number of
615 pins supported by a particular chip.
617 Note that if the GPIO device uses I2C, then the I2C interface
618 must also be configured. See I2C Support, below.
621 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
622 accesses and can checksum them or write a list of them out
623 to memory. See the 'iotrace' command for details. This is
624 useful for testing device drivers since it can confirm that
625 the driver behaves the same way before and after a code
626 change. Currently this is supported on sandbox and arm. To
627 add support for your architecture, add '#include <iotrace.h>'
628 to the bottom of arch/<arch>/include/asm/io.h and test.
630 Example output from the 'iotrace stats' command is below.
631 Note that if the trace buffer is exhausted, the checksum will
632 still continue to operate.
635 Start: 10000000 (buffer start address)
636 Size: 00010000 (buffer size)
637 Offset: 00000120 (current buffer offset)
638 Output: 10000120 (start + offset)
639 Count: 00000018 (number of trace records)
640 CRC32: 9526fb66 (CRC32 of all trace records)
644 When CONFIG_TIMESTAMP is selected, the timestamp
645 (date and time) of an image is printed by image
646 commands like bootm or iminfo. This option is
647 automatically enabled when you select CONFIG_CMD_DATE .
649 - Partition Labels (disklabels) Supported:
650 Zero or more of the following:
651 CONFIG_MAC_PARTITION Apple's MacOS partition table.
652 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
653 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
654 bootloader. Note 2TB partition limit; see
656 CONFIG_SCSI) you must configure support for at
657 least one non-MTD partition type as well.
659 - NETWORK Support (PCI):
661 Utility code for direct access to the SPI bus on Intel 8257x.
662 This does not do anything useful unless you set at least one
663 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
666 Support for National dp83815 chips.
669 Support for National dp8382[01] gigabit chips.
671 - NETWORK Support (other):
673 Support for the Calxeda XGMAC device
676 Support for SMSC's LAN91C96 chips.
678 CONFIG_LAN91C96_USE_32_BIT
679 Define this to enable 32 bit addressing
682 Support for SMSC's LAN91C111 chip
685 Define this to hold the physical address
686 of the device (I/O space)
688 CONFIG_SMC_USE_32_BIT
689 Define this if data bus is 32 bits
691 CONFIG_SMC_USE_IOFUNCS
692 Define this to use i/o functions instead of macros
693 (some hardware wont work with macros)
695 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
696 Define this if you have more then 3 PHYs.
699 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
701 CONFIG_FTGMAC100_EGIGA
702 Define this to use GE link update with gigabit PHY.
703 Define this if FTGMAC100 is connected to gigabit PHY.
704 If your system has 10/100 PHY only, it might not occur
705 wrong behavior. Because PHY usually return timeout or
706 useless data when polling gigabit status and gigabit
707 control registers. This behavior won't affect the
708 correctnessof 10/100 link speed update.
711 Support for Renesas on-chip Ethernet controller
713 CONFIG_SH_ETHER_USE_PORT
714 Define the number of ports to be used
716 CONFIG_SH_ETHER_PHY_ADDR
717 Define the ETH PHY's address
719 CONFIG_SH_ETHER_CACHE_WRITEBACK
720 If this option is set, the driver enables cache flush.
726 CONFIG_TPM_TIS_INFINEON
727 Support for Infineon i2c bus TPM devices. Only one device
728 per system is supported at this time.
730 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
731 Define the burst count bytes upper limit
734 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
736 CONFIG_TPM_ST33ZP24_I2C
737 Support for STMicroelectronics ST33ZP24 I2C devices.
738 Requires TPM_ST33ZP24 and I2C.
740 CONFIG_TPM_ST33ZP24_SPI
741 Support for STMicroelectronics ST33ZP24 SPI devices.
742 Requires TPM_ST33ZP24 and SPI.
745 Support for Atmel TWI TPM device. Requires I2C support.
748 Support for generic parallel port TPM devices. Only one device
749 per system is supported at this time.
751 CONFIG_TPM_TIS_BASE_ADDRESS
752 Base address where the generic TPM device is mapped
753 to. Contemporary x86 systems usually map it at
757 Define this to enable the TPM support library which provides
758 functional interfaces to some TPM commands.
759 Requires support for a TPM device.
761 CONFIG_TPM_AUTH_SESSIONS
762 Define this to enable authorized functions in the TPM library.
763 Requires CONFIG_TPM and CONFIG_SHA1.
766 At the moment only the UHCI host controller is
767 supported (PIP405, MIP405); define
768 CONFIG_USB_UHCI to enable it.
769 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
770 and define CONFIG_USB_STORAGE to enable the USB
773 Supported are USB Keyboards and USB Floppy drives
776 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
780 Define the below if you wish to use the USB console.
781 Once firmware is rebuilt from a serial console issue the
782 command "setenv stdin usbtty; setenv stdout usbtty" and
783 attach your USB cable. The Unix command "dmesg" should print
784 it has found a new device. The environment variable usbtty
785 can be set to gserial or cdc_acm to enable your device to
786 appear to a USB host as a Linux gserial device or a
787 Common Device Class Abstract Control Model serial device.
788 If you select usbtty = gserial you should be able to enumerate
790 # modprobe usbserial vendor=0xVendorID product=0xProductID
791 else if using cdc_acm, simply setting the environment
792 variable usbtty to be cdc_acm should suffice. The following
793 might be defined in YourBoardName.h
796 Define this to build a UDC device
799 Define this to have a tty type of device available to
800 talk to the UDC device
803 Define this to enable the high speed support for usb
804 device and usbtty. If this feature is enabled, a routine
805 int is_usbd_high_speed(void)
806 also needs to be defined by the driver to dynamically poll
807 whether the enumeration has succeded at high speed or full
810 If you have a USB-IF assigned VendorID then you may wish to
811 define your own vendor specific values either in BoardName.h
812 or directly in usbd_vendor_info.h. If you don't define
813 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
814 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
815 should pretend to be a Linux device to it's target host.
817 CONFIG_USBD_MANUFACTURER
818 Define this string as the name of your company for
819 - CONFIG_USBD_MANUFACTURER "my company"
821 CONFIG_USBD_PRODUCT_NAME
822 Define this string as the name of your product
823 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
826 Define this as your assigned Vendor ID from the USB
827 Implementors Forum. This *must* be a genuine Vendor ID
828 to avoid polluting the USB namespace.
829 - CONFIG_USBD_VENDORID 0xFFFF
831 CONFIG_USBD_PRODUCTID
832 Define this as the unique Product ID
834 - CONFIG_USBD_PRODUCTID 0xFFFF
836 - ULPI Layer Support:
837 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
838 the generic ULPI layer. The generic layer accesses the ULPI PHY
839 via the platform viewport, so you need both the genric layer and
840 the viewport enabled. Currently only Chipidea/ARC based
841 viewport is supported.
842 To enable the ULPI layer support, define CONFIG_USB_ULPI and
843 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
844 If your ULPI phy needs a different reference clock than the
845 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
846 the appropriate value in Hz.
850 Support for Renesas on-chip MMCIF controller
853 Define the base address of MMCIF registers
856 Define the clock frequency for MMCIF
858 - USB Device Firmware Update (DFU) class support:
860 This enables the USB portion of the DFU USB class
863 This enables support for exposing NAND devices via DFU.
866 This enables support for exposing RAM via DFU.
867 Note: DFU spec refer to non-volatile memory usage, but
868 allow usages beyond the scope of spec - here RAM usage,
869 one that would help mostly the developer.
871 CONFIG_SYS_DFU_DATA_BUF_SIZE
872 Dfu transfer uses a buffer before writing data to the
873 raw storage device. Make the size (in bytes) of this buffer
874 configurable. The size of this buffer is also configurable
875 through the "dfu_bufsiz" environment variable.
877 CONFIG_SYS_DFU_MAX_FILE_SIZE
878 When updating files rather than the raw storage device,
879 we use a static buffer to copy the file into and then write
880 the buffer once we've been given the whole file. Define
881 this to the maximum filesize (in bytes) for the buffer.
882 Default is 4 MiB if undefined.
884 DFU_DEFAULT_POLL_TIMEOUT
885 Poll timeout [ms], is the timeout a device can send to the
886 host. The host must wait for this timeout before sending
887 a subsequent DFU_GET_STATUS request to the device.
889 DFU_MANIFEST_POLL_TIMEOUT
890 Poll timeout [ms], which the device sends to the host when
891 entering dfuMANIFEST state. Host waits this timeout, before
892 sending again an USB request to the device.
894 - Journaling Flash filesystem support:
895 CONFIG_SYS_JFFS2_FIRST_SECTOR,
896 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
897 Define these for a default partition on a NOR device
900 See Kconfig help for available keyboard drivers.
902 - LCD Support: CONFIG_LCD
904 Define this to enable LCD support (for output to LCD
905 display); also select one of the supported displays
906 by defining one of these:
908 CONFIG_NEC_NL6448AC33:
910 NEC NL6448AC33-18. Active, color, single scan.
912 CONFIG_NEC_NL6448BC20
914 NEC NL6448BC20-08. 6.5", 640x480.
915 Active, color, single scan.
917 CONFIG_NEC_NL6448BC33_54
919 NEC NL6448BC33-54. 10.4", 640x480.
920 Active, color, single scan.
924 Sharp 320x240. Active, color, single scan.
925 It isn't 16x9, and I am not sure what it is.
927 CONFIG_SHARP_LQ64D341
929 Sharp LQ64D341 display, 640x480.
930 Active, color, single scan.
934 HLD1045 display, 640x480.
935 Active, color, single scan.
939 Optrex CBL50840-2 NF-FW 99 22 M5
941 Hitachi LMG6912RPFC-00T
945 320x240. Black & white.
949 Normally the LCD is page-aligned (typically 4KB). If this is
950 defined then the LCD will be aligned to this value instead.
951 For ARM it is sometimes useful to use MMU_SECTION_SIZE
952 here, since it is cheaper to change data cache settings on
958 Sometimes, for example if the display is mounted in portrait
959 mode or even if it's mounted landscape but rotated by 180degree,
960 we need to rotate our content of the display relative to the
961 framebuffer, so that user can read the messages which are
963 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
964 initialized with a given rotation from "vl_rot" out of
965 "vidinfo_t" which is provided by the board specific code.
966 The value for vl_rot is coded as following (matching to
967 fbcon=rotate:<n> linux-kernel commandline):
968 0 = no rotation respectively 0 degree
969 1 = 90 degree rotation
970 2 = 180 degree rotation
971 3 = 270 degree rotation
973 If CONFIG_LCD_ROTATION is not defined, the console will be
974 initialized with 0degree rotation.
977 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
979 The clock frequency of the MII bus
981 CONFIG_PHY_CMD_DELAY (ppc4xx)
983 Some PHY like Intel LXT971A need extra delay after
984 command issued before MII status register can be read
989 Define a default value for the IP address to use for
990 the default Ethernet interface, in case this is not
991 determined through e.g. bootp.
992 (Environment variable "ipaddr")
997 Defines a default value for the IP address of a TFTP
998 server to contact when using the "tftboot" command.
999 (Environment variable "serverip")
1001 - Gateway IP address:
1004 Defines a default value for the IP address of the
1005 default router where packets to other networks are
1007 (Environment variable "gatewayip")
1012 Defines a default value for the subnet mask (or
1013 routing prefix) which is used to determine if an IP
1014 address belongs to the local subnet or needs to be
1015 forwarded through a router.
1016 (Environment variable "netmask")
1018 - BOOTP Recovery Mode:
1019 CONFIG_BOOTP_RANDOM_DELAY
1021 If you have many targets in a network that try to
1022 boot using BOOTP, you may want to avoid that all
1023 systems send out BOOTP requests at precisely the same
1024 moment (which would happen for instance at recovery
1025 from a power failure, when all systems will try to
1026 boot, thus flooding the BOOTP server. Defining
1027 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1028 inserted before sending out BOOTP requests. The
1029 following delays are inserted then:
1031 1st BOOTP request: delay 0 ... 1 sec
1032 2nd BOOTP request: delay 0 ... 2 sec
1033 3rd BOOTP request: delay 0 ... 4 sec
1035 BOOTP requests: delay 0 ... 8 sec
1037 CONFIG_BOOTP_ID_CACHE_SIZE
1039 BOOTP packets are uniquely identified using a 32-bit ID. The
1040 server will copy the ID from client requests to responses and
1041 U-Boot will use this to determine if it is the destination of
1042 an incoming response. Some servers will check that addresses
1043 aren't in use before handing them out (usually using an ARP
1044 ping) and therefore take up to a few hundred milliseconds to
1045 respond. Network congestion may also influence the time it
1046 takes for a response to make it back to the client. If that
1047 time is too long, U-Boot will retransmit requests. In order
1048 to allow earlier responses to still be accepted after these
1049 retransmissions, U-Boot's BOOTP client keeps a small cache of
1050 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1051 cache. The default is to keep IDs for up to four outstanding
1052 requests. Increasing this will allow U-Boot to accept offers
1053 from a BOOTP client in networks with unusually high latency.
1055 - DHCP Advanced Options:
1057 - Link-local IP address negotiation:
1058 Negotiate with other link-local clients on the local network
1059 for an address that doesn't require explicit configuration.
1060 This is especially useful if a DHCP server cannot be guaranteed
1061 to exist in all environments that the device must operate.
1063 See doc/README.link-local for more information.
1065 - MAC address from environment variables
1067 FDT_SEQ_MACADDR_FROM_ENV
1069 Fix-up device tree with MAC addresses fetched sequentially from
1070 environment variables. This config work on assumption that
1071 non-usable ethernet node of device-tree are either not present
1072 or their status has been marked as "disabled".
1075 CONFIG_CDP_DEVICE_ID
1077 The device id used in CDP trigger frames.
1079 CONFIG_CDP_DEVICE_ID_PREFIX
1081 A two character string which is prefixed to the MAC address
1086 A printf format string which contains the ascii name of
1087 the port. Normally is set to "eth%d" which sets
1088 eth0 for the first Ethernet, eth1 for the second etc.
1090 CONFIG_CDP_CAPABILITIES
1092 A 32bit integer which indicates the device capabilities;
1093 0x00000010 for a normal host which does not forwards.
1097 An ascii string containing the version of the software.
1101 An ascii string containing the name of the platform.
1105 A 32bit integer sent on the trigger.
1107 CONFIG_CDP_POWER_CONSUMPTION
1109 A 16bit integer containing the power consumption of the
1110 device in .1 of milliwatts.
1112 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1114 A byte containing the id of the VLAN.
1116 - Status LED: CONFIG_LED_STATUS
1118 Several configurations allow to display the current
1119 status using a LED. For instance, the LED will blink
1120 fast while running U-Boot code, stop blinking as
1121 soon as a reply to a BOOTP request was received, and
1122 start blinking slow once the Linux kernel is running
1123 (supported by a status LED driver in the Linux
1124 kernel). Defining CONFIG_LED_STATUS enables this
1129 CONFIG_LED_STATUS_GPIO
1130 The status LED can be connected to a GPIO pin.
1131 In such cases, the gpio_led driver can be used as a
1132 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1133 to include the gpio_led driver in the U-Boot binary.
1135 CONFIG_GPIO_LED_INVERTED_TABLE
1136 Some GPIO connected LEDs may have inverted polarity in which
1137 case the GPIO high value corresponds to LED off state and
1138 GPIO low value corresponds to LED on state.
1139 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
1140 with a list of GPIO LEDs that have inverted polarity.
1143 CONFIG_SYS_NUM_I2C_BUSES
1144 Hold the number of i2c buses you want to use.
1146 CONFIG_SYS_I2C_DIRECT_BUS
1147 define this, if you don't use i2c muxes on your hardware.
1148 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
1151 CONFIG_SYS_I2C_MAX_HOPS
1152 define how many muxes are maximal consecutively connected
1153 on one i2c bus. If you not use i2c muxes, omit this
1156 CONFIG_SYS_I2C_BUSES
1157 hold a list of buses you want to use, only used if
1158 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
1159 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
1160 CONFIG_SYS_NUM_I2C_BUSES = 9:
1162 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
1163 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
1164 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
1165 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
1166 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
1167 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
1168 {1, {I2C_NULL_HOP}}, \
1169 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
1170 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
1174 bus 0 on adapter 0 without a mux
1175 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
1176 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
1177 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
1178 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
1179 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
1180 bus 6 on adapter 1 without a mux
1181 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
1182 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
1184 If you do not have i2c muxes on your board, omit this define.
1186 - Legacy I2C Support:
1187 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
1188 then the following macros need to be defined (examples are
1189 from include/configs/lwmon.h):
1193 (Optional). Any commands necessary to enable the I2C
1194 controller or configure ports.
1196 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1200 The code necessary to make the I2C data line active
1201 (driven). If the data line is open collector, this
1204 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1208 The code necessary to make the I2C data line tri-stated
1209 (inactive). If the data line is open collector, this
1212 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1216 Code that returns true if the I2C data line is high,
1219 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1223 If <bit> is true, sets the I2C data line high. If it
1224 is false, it clears it (low).
1226 eg: #define I2C_SDA(bit) \
1227 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1228 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1232 If <bit> is true, sets the I2C clock line high. If it
1233 is false, it clears it (low).
1235 eg: #define I2C_SCL(bit) \
1236 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1237 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1241 This delay is invoked four times per clock cycle so this
1242 controls the rate of data transfer. The data rate thus
1243 is 1 / (I2C_DELAY * 4). Often defined to be something
1246 #define I2C_DELAY udelay(2)
1248 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1250 If your arch supports the generic GPIO framework (asm/gpio.h),
1251 then you may alternatively define the two GPIOs that are to be
1252 used as SCL / SDA. Any of the previous I2C_xxx macros will
1253 have GPIO-based defaults assigned to them as appropriate.
1255 You should define these to the GPIO value as given directly to
1256 the generic GPIO functions.
1258 CONFIG_SYS_I2C_INIT_BOARD
1260 When a board is reset during an i2c bus transfer
1261 chips might think that the current transfer is still
1262 in progress. On some boards it is possible to access
1263 the i2c SCLK line directly, either by using the
1264 processor pin as a GPIO or by having a second pin
1265 connected to the bus. If this option is defined a
1266 custom i2c_init_board() routine in boards/xxx/board.c
1267 is run early in the boot sequence.
1269 CONFIG_I2C_MULTI_BUS
1271 This option allows the use of multiple I2C buses, each of which
1272 must have a controller. At any point in time, only one bus is
1273 active. To switch to a different bus, use the 'i2c dev' command.
1274 Note that bus numbering is zero-based.
1276 CONFIG_SYS_I2C_NOPROBES
1278 This option specifies a list of I2C devices that will be skipped
1279 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1280 is set, specify a list of bus-device pairs. Otherwise, specify
1281 a 1D array of device addresses
1284 #undef CONFIG_I2C_MULTI_BUS
1285 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1287 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1289 #define CONFIG_I2C_MULTI_BUS
1290 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1292 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1294 CONFIG_SYS_RTC_BUS_NUM
1296 If defined, then this indicates the I2C bus number for the RTC.
1297 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1299 CONFIG_SOFT_I2C_READ_REPEATED_START
1301 defining this will force the i2c_read() function in
1302 the soft_i2c driver to perform an I2C repeated start
1303 between writing the address pointer and reading the
1304 data. If this define is omitted the default behaviour
1305 of doing a stop-start sequence will be used. Most I2C
1306 devices can use either method, but some require one or
1309 - SPI Support: CONFIG_SPI
1311 Enables SPI driver (so far only tested with
1312 SPI EEPROM, also an instance works with Crystal A/D and
1313 D/As on the SACSng board)
1315 CONFIG_SYS_SPI_MXC_WAIT
1316 Timeout for waiting until spi transfer completed.
1317 default: (CONFIG_SYS_HZ/100) /* 10 ms */
1319 - FPGA Support: CONFIG_FPGA
1321 Enables FPGA subsystem.
1323 CONFIG_FPGA_<vendor>
1325 Enables support for specific chip vendors.
1328 CONFIG_FPGA_<family>
1330 Enables support for FPGA family.
1331 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1333 CONFIG_SYS_FPGA_CHECK_BUSY
1335 Enable checks on FPGA configuration interface busy
1336 status by the configuration function. This option
1337 will require a board or device specific function to
1342 If defined, a function that provides delays in the FPGA
1343 configuration driver.
1345 CONFIG_SYS_FPGA_CHECK_ERROR
1347 Check for configuration errors during FPGA bitfile
1348 loading. For example, abort during Virtex II
1349 configuration if the INIT_B line goes low (which
1350 indicated a CRC error).
1352 CONFIG_SYS_FPGA_WAIT_INIT
1354 Maximum time to wait for the INIT_B line to de-assert
1355 after PROB_B has been de-asserted during a Virtex II
1356 FPGA configuration sequence. The default time is 500
1359 CONFIG_SYS_FPGA_WAIT_BUSY
1361 Maximum time to wait for BUSY to de-assert during
1362 Virtex II FPGA configuration. The default is 5 ms.
1364 CONFIG_SYS_FPGA_WAIT_CONFIG
1366 Time to wait after FPGA configuration. The default is
1369 - Vendor Parameter Protection:
1371 U-Boot considers the values of the environment
1372 variables "serial#" (Board Serial Number) and
1373 "ethaddr" (Ethernet Address) to be parameters that
1374 are set once by the board vendor / manufacturer, and
1375 protects these variables from casual modification by
1376 the user. Once set, these variables are read-only,
1377 and write or delete attempts are rejected. You can
1378 change this behaviour:
1380 If CONFIG_ENV_OVERWRITE is #defined in your config
1381 file, the write protection for vendor parameters is
1382 completely disabled. Anybody can change or delete
1385 Alternatively, if you define _both_ an ethaddr in the
1386 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1387 Ethernet address is installed in the environment,
1388 which can be changed exactly ONCE by the user. [The
1389 serial# is unaffected by this, i. e. it remains
1392 The same can be accomplished in a more flexible way
1393 for any variable by configuring the type of access
1394 to allow for those variables in the ".flags" variable
1395 or define CONFIG_ENV_FLAGS_LIST_STATIC.
1400 Define this variable to enable the reservation of
1401 "protected RAM", i. e. RAM which is not overwritten
1402 by U-Boot. Define CONFIG_PRAM to hold the number of
1403 kB you want to reserve for pRAM. You can overwrite
1404 this default value by defining an environment
1405 variable "pram" to the number of kB you want to
1406 reserve. Note that the board info structure will
1407 still show the full amount of RAM. If pRAM is
1408 reserved, a new environment variable "mem" will
1409 automatically be defined to hold the amount of
1410 remaining RAM in a form that can be passed as boot
1411 argument to Linux, for instance like that:
1413 setenv bootargs ... mem=\${mem}
1416 This way you can tell Linux not to use this memory,
1417 either, which results in a memory region that will
1418 not be affected by reboots.
1420 *WARNING* If your board configuration uses automatic
1421 detection of the RAM size, you must make sure that
1422 this memory test is non-destructive. So far, the
1423 following board configurations are known to be
1426 IVMS8, IVML24, SPD8xx,
1427 HERMES, IP860, RPXlite, LWMON,
1433 In the current implementation, the local variables
1434 space and global environment variables space are
1435 separated. Local variables are those you define by
1436 simply typing `name=value'. To access a local
1437 variable later on, you have write `$name' or
1438 `${name}'; to execute the contents of a variable
1439 directly type `$name' at the command prompt.
1441 Global environment variables are those you use
1442 setenv/printenv to work with. To run a command stored
1443 in such a variable, you need to use the run command,
1444 and you must not use the '$' sign to access them.
1446 To store commands and special characters in a
1447 variable, please use double quotation marks
1448 surrounding the whole text of the variable, instead
1449 of the backslashes before semicolons and special
1452 - Default Environment:
1453 CONFIG_EXTRA_ENV_SETTINGS
1455 Define this to contain any number of null terminated
1456 strings (variable = value pairs) that will be part of
1457 the default environment compiled into the boot image.
1459 For example, place something like this in your
1460 board's config file:
1462 #define CONFIG_EXTRA_ENV_SETTINGS \
1466 Warning: This method is based on knowledge about the
1467 internal format how the environment is stored by the
1468 U-Boot code. This is NOT an official, exported
1469 interface! Although it is unlikely that this format
1470 will change soon, there is no guarantee either.
1471 You better know what you are doing here.
1473 Note: overly (ab)use of the default environment is
1474 discouraged. Make sure to check other ways to preset
1475 the environment like the "source" command or the
1478 CONFIG_DELAY_ENVIRONMENT
1480 Normally the environment is loaded when the board is
1481 initialised so that it is available to U-Boot. This inhibits
1482 that so that the environment is not available until
1483 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
1484 this is instead controlled by the value of
1485 /config/load-environment.
1487 CONFIG_STANDALONE_LOAD_ADDR
1489 This option defines a board specific value for the
1490 address where standalone program gets loaded, thus
1491 overwriting the architecture dependent default
1494 - Automatic software updates via TFTP server
1496 CONFIG_UPDATE_TFTP_CNT_MAX
1497 CONFIG_UPDATE_TFTP_MSEC_MAX
1499 These options enable and control the auto-update feature;
1500 for a more detailed description refer to doc/README.update.
1502 - MTD Support (mtdparts command, UBI support)
1503 CONFIG_MTD_UBI_WL_THRESHOLD
1504 This parameter defines the maximum difference between the highest
1505 erase counter value and the lowest erase counter value of eraseblocks
1506 of UBI devices. When this threshold is exceeded, UBI starts performing
1507 wear leveling by means of moving data from eraseblock with low erase
1508 counter to eraseblocks with high erase counter.
1510 The default value should be OK for SLC NAND flashes, NOR flashes and
1511 other flashes which have eraseblock life-cycle 100000 or more.
1512 However, in case of MLC NAND flashes which typically have eraseblock
1513 life-cycle less than 10000, the threshold should be lessened (e.g.,
1514 to 128 or 256, although it does not have to be power of 2).
1518 CONFIG_MTD_UBI_BEB_LIMIT
1519 This option specifies the maximum bad physical eraseblocks UBI
1520 expects on the MTD device (per 1024 eraseblocks). If the
1521 underlying flash does not admit of bad eraseblocks (e.g. NOR
1522 flash), this value is ignored.
1524 NAND datasheets often specify the minimum and maximum NVM
1525 (Number of Valid Blocks) for the flashes' endurance lifetime.
1526 The maximum expected bad eraseblocks per 1024 eraseblocks
1527 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
1528 which gives 20 for most NANDs (MaxNVB is basically the total
1529 count of eraseblocks on the chip).
1531 To put it differently, if this value is 20, UBI will try to
1532 reserve about 1.9% of physical eraseblocks for bad blocks
1533 handling. And that will be 1.9% of eraseblocks on the entire
1534 NAND chip, not just the MTD partition UBI attaches. This means
1535 that if you have, say, a NAND flash chip admits maximum 40 bad
1536 eraseblocks, and it is split on two MTD partitions of the same
1537 size, UBI will reserve 40 eraseblocks when attaching a
1542 CONFIG_MTD_UBI_FASTMAP
1543 Fastmap is a mechanism which allows attaching an UBI device
1544 in nearly constant time. Instead of scanning the whole MTD device it
1545 only has to locate a checkpoint (called fastmap) on the device.
1546 The on-flash fastmap contains all information needed to attach
1547 the device. Using fastmap makes only sense on large devices where
1548 attaching by scanning takes long. UBI will not automatically install
1549 a fastmap on old images, but you can set the UBI parameter
1550 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
1551 that fastmap-enabled images are still usable with UBI implementations
1552 without fastmap support. On typical flash devices the whole fastmap
1553 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
1555 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
1556 Set this parameter to enable fastmap automatically on images
1560 CONFIG_MTD_UBI_FM_DEBUG
1561 Enable UBI fastmap debug
1566 Enable building of SPL globally.
1568 CONFIG_SPL_PANIC_ON_RAW_IMAGE
1569 When defined, SPL will panic() if the image it has
1570 loaded does not have a signature.
1571 Defining this is useful when code which loads images
1572 in SPL cannot guarantee that absolutely all read errors
1574 An example is the LPC32XX MLC NAND driver, which will
1575 consider that a completely unreadable NAND block is bad,
1576 and thus should be skipped silently.
1578 CONFIG_SPL_DISPLAY_PRINT
1579 For ARM, enable an optional function to print more information
1580 about the running system.
1582 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
1583 Set this for NAND SPL on PPC mpc83xx targets, so that
1584 start.S waits for the rest of the SPL to load before
1585 continuing (the hardware starts execution after just
1586 loading the first page rather than the full 4K).
1589 Support for a lightweight UBI (fastmap) scanner and
1592 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
1593 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
1594 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
1595 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
1596 CONFIG_SYS_NAND_ECCBYTES
1597 Defines the size and behavior of the NAND that SPL uses
1600 CONFIG_SYS_NAND_U_BOOT_DST
1601 Location in memory to load U-Boot to
1603 CONFIG_SYS_NAND_U_BOOT_SIZE
1604 Size of image to load
1606 CONFIG_SYS_NAND_U_BOOT_START
1607 Entry point in loaded image to jump to
1609 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
1610 Define this if you need to first read the OOB and then the
1611 data. This is used, for example, on davinci platforms.
1613 CONFIG_SPL_RAM_DEVICE
1614 Support for running image already present in ram, in SPL binary
1616 CONFIG_SPL_FIT_PRINT
1617 Printing information about a FIT image adds quite a bit of
1618 code to SPL. So this is normally disabled in SPL. Use this
1619 option to re-enable it. This will affect the output of the
1620 bootm command when booting a FIT image.
1622 - Interrupt support (PPC):
1624 There are common interrupt_init() and timer_interrupt()
1625 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1626 for CPU specific initialization. interrupt_init_cpu()
1627 should set decrementer_count to appropriate value. If
1628 CPU resets decrementer automatically after interrupt
1629 (ppc4xx) it should set decrementer_count to zero.
1630 timer_interrupt() calls timer_interrupt_cpu() for CPU
1631 specific handling. If board has watchdog / status_led
1632 / other_activity_monitor it works automatically from
1633 general timer_interrupt().
1636 Board initialization settings:
1637 ------------------------------
1639 During Initialization u-boot calls a number of board specific functions
1640 to allow the preparation of board specific prerequisites, e.g. pin setup
1641 before drivers are initialized. To enable these callbacks the
1642 following configuration macros have to be defined. Currently this is
1643 architecture specific, so please check arch/your_architecture/lib/board.c
1644 typically in board_init_f() and board_init_r().
1646 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
1647 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
1648 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
1650 Configuration Settings:
1651 -----------------------
1653 - MEM_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
1654 Optionally it can be defined to support 64-bit memory commands.
1656 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
1657 undefine this when you're short of memory.
1659 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
1660 width of the commands listed in the 'help' command output.
1662 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
1663 prompt for user input.
1665 - CONFIG_SYS_BAUDRATE_TABLE:
1666 List of legal baudrate settings for this board.
1668 - CONFIG_SYS_MEM_RESERVE_SECURE
1669 Only implemented for ARMv8 for now.
1670 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
1671 is substracted from total RAM and won't be reported to OS.
1672 This memory can be used as secure memory. A variable
1673 gd->arch.secure_ram is used to track the location. In systems
1674 the RAM base is not zero, or RAM is divided into banks,
1675 this variable needs to be recalcuated to get the address.
1677 - CONFIG_SYS_LOADS_BAUD_CHANGE:
1678 Enable temporary baudrate change while serial download
1680 - CONFIG_SYS_SDRAM_BASE:
1681 Physical start address of SDRAM. _Must_ be 0 here.
1683 - CONFIG_SYS_FLASH_BASE:
1684 Physical start address of Flash memory.
1686 - CONFIG_SYS_MONITOR_LEN:
1687 Size of memory reserved for monitor code, used to
1688 determine _at_compile_time_ (!) if the environment is
1689 embedded within the U-Boot image, or in a separate
1692 - CONFIG_SYS_MALLOC_LEN:
1693 Size of DRAM reserved for malloc() use.
1695 - CONFIG_SYS_MALLOC_F_LEN
1696 Size of the malloc() pool for use before relocation. If
1697 this is defined, then a very simple malloc() implementation
1698 will become available before relocation. The address is just
1699 below the global data, and the stack is moved down to make
1702 This feature allocates regions with increasing addresses
1703 within the region. calloc() is supported, but realloc()
1704 is not available. free() is supported but does nothing.
1705 The memory will be freed (or in fact just forgotten) when
1706 U-Boot relocates itself.
1708 - CONFIG_SYS_MALLOC_SIMPLE
1709 Provides a simple and small malloc() and calloc() for those
1710 boards which do not use the full malloc in SPL (which is
1711 enabled with CONFIG_SYS_SPL_MALLOC).
1713 - CONFIG_SYS_NONCACHED_MEMORY:
1714 Size of non-cached memory area. This area of memory will be
1715 typically located right below the malloc() area and mapped
1716 uncached in the MMU. This is useful for drivers that would
1717 otherwise require a lot of explicit cache maintenance. For
1718 some drivers it's also impossible to properly maintain the
1719 cache. For example if the regions that need to be flushed
1720 are not a multiple of the cache-line size, *and* padding
1721 cannot be allocated between the regions to align them (i.e.
1722 if the HW requires a contiguous array of regions, and the
1723 size of each region is not cache-aligned), then a flush of
1724 one region may result in overwriting data that hardware has
1725 written to another region in the same cache-line. This can
1726 happen for example in network drivers where descriptors for
1727 buffers are typically smaller than the CPU cache-line (e.g.
1728 16 bytes vs. 32 or 64 bytes).
1730 Non-cached memory is only supported on 32-bit ARM at present.
1732 - CONFIG_SYS_BOOTMAPSZ:
1733 Maximum size of memory mapped by the startup code of
1734 the Linux kernel; all data that must be processed by
1735 the Linux kernel (bd_info, boot arguments, FDT blob if
1736 used) must be put below this limit, unless "bootm_low"
1737 environment variable is defined and non-zero. In such case
1738 all data for the Linux kernel must be between "bootm_low"
1739 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
1740 variable "bootm_mapsize" will override the value of
1741 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
1742 then the value in "bootm_size" will be used instead.
1744 - CONFIG_SYS_BOOT_GET_CMDLINE:
1745 Enables allocating and saving kernel cmdline in space between
1746 "bootm_low" and "bootm_low" + BOOTMAPSZ.
1748 - CONFIG_SYS_BOOT_GET_KBD:
1749 Enables allocating and saving a kernel copy of the bd_info in
1750 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
1752 - CONFIG_SYS_MAX_FLASH_SECT:
1753 Max number of sectors on a Flash chip
1755 - CONFIG_SYS_FLASH_ERASE_TOUT:
1756 Timeout for Flash erase operations (in ms)
1758 - CONFIG_SYS_FLASH_WRITE_TOUT:
1759 Timeout for Flash write operations (in ms)
1761 - CONFIG_SYS_FLASH_LOCK_TOUT
1762 Timeout for Flash set sector lock bit operation (in ms)
1764 - CONFIG_SYS_FLASH_UNLOCK_TOUT
1765 Timeout for Flash clear lock bits operation (in ms)
1767 - CONFIG_SYS_FLASH_PROTECTION
1768 If defined, hardware flash sectors protection is used
1769 instead of U-Boot software protection.
1771 - CONFIG_SYS_DIRECT_FLASH_TFTP:
1773 Enable TFTP transfers directly to flash memory;
1774 without this option such a download has to be
1775 performed in two steps: (1) download to RAM, and (2)
1776 copy from RAM to flash.
1778 The two-step approach is usually more reliable, since
1779 you can check if the download worked before you erase
1780 the flash, but in some situations (when system RAM is
1781 too limited to allow for a temporary copy of the
1782 downloaded image) this option may be very useful.
1784 - CONFIG_SYS_FLASH_CFI:
1785 Define if the flash driver uses extra elements in the
1786 common flash structure for storing flash geometry.
1788 - CONFIG_FLASH_CFI_DRIVER
1789 This option also enables the building of the cfi_flash driver
1790 in the drivers directory
1792 - CONFIG_FLASH_CFI_MTD
1793 This option enables the building of the cfi_mtd driver
1794 in the drivers directory. The driver exports CFI flash
1797 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
1798 Use buffered writes to flash.
1800 - CONFIG_FLASH_SPANSION_S29WS_N
1801 s29ws-n MirrorBit flash has non-standard addresses for buffered
1804 - CONFIG_SYS_FLASH_QUIET_TEST
1805 If this option is defined, the common CFI flash doesn't
1806 print it's warning upon not recognized FLASH banks. This
1807 is useful, if some of the configured banks are only
1808 optionally available.
1810 - CONFIG_FLASH_SHOW_PROGRESS
1811 If defined (must be an integer), print out countdown
1812 digits and dots. Recommended value: 45 (9..1) for 80
1813 column displays, 15 (3..1) for 40 column displays.
1815 - CONFIG_FLASH_VERIFY
1816 If defined, the content of the flash (destination) is compared
1817 against the source after the write operation. An error message
1818 will be printed when the contents are not identical.
1819 Please note that this option is useless in nearly all cases,
1820 since such flash programming errors usually are detected earlier
1821 while unprotecting/erasing/programming. Please only enable
1822 this option if you really know what you are doing.
1824 - CONFIG_ENV_FLAGS_LIST_DEFAULT
1825 - CONFIG_ENV_FLAGS_LIST_STATIC
1826 Enable validation of the values given to environment variables when
1827 calling env set. Variables can be restricted to only decimal,
1828 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
1829 the variables can also be restricted to IP address or MAC address.
1831 The format of the list is:
1832 type_attribute = [s|d|x|b|i|m]
1833 access_attribute = [a|r|o|c]
1834 attributes = type_attribute[access_attribute]
1835 entry = variable_name[:attributes]
1838 The type attributes are:
1839 s - String (default)
1842 b - Boolean ([1yYtT|0nNfF])
1846 The access attributes are:
1852 - CONFIG_ENV_FLAGS_LIST_DEFAULT
1853 Define this to a list (string) to define the ".flags"
1854 environment variable in the default or embedded environment.
1856 - CONFIG_ENV_FLAGS_LIST_STATIC
1857 Define this to a list (string) to define validation that
1858 should be done if an entry is not found in the ".flags"
1859 environment variable. To override a setting in the static
1860 list, simply add an entry for the same variable name to the
1863 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
1864 regular expression. This allows multiple variables to define the same
1865 flags without explicitly listing them for each variable.
1867 The following definitions that deal with the placement and management
1868 of environment data (variable area); in general, we support the
1869 following configurations:
1871 - CONFIG_BUILD_ENVCRC:
1873 Builds up envcrc with the target environment so that external utils
1874 may easily extract it and embed it in final U-Boot images.
1876 BE CAREFUL! The first access to the environment happens quite early
1877 in U-Boot initialization (when we try to get the setting of for the
1878 console baudrate). You *MUST* have mapped your NVRAM area then, or
1881 Please note that even with NVRAM we still use a copy of the
1882 environment in RAM: we could work on NVRAM directly, but we want to
1883 keep settings there always unmodified except somebody uses "saveenv"
1884 to save the current settings.
1886 BE CAREFUL! For some special cases, the local device can not use
1887 "saveenv" command. For example, the local device will get the
1888 environment stored in a remote NOR flash by SRIO or PCIE link,
1889 but it can not erase, write this NOR flash by SRIO or PCIE interface.
1891 - CONFIG_NAND_ENV_DST
1893 Defines address in RAM to which the nand_spl code should copy the
1894 environment. If redundant environment is used, it will be copied to
1895 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
1897 Please note that the environment is read-only until the monitor
1898 has been relocated to RAM and a RAM copy of the environment has been
1899 created; also, when using EEPROM you will have to use env_get_f()
1900 until then to read environment variables.
1902 The environment is protected by a CRC32 checksum. Before the monitor
1903 is relocated into RAM, as a result of a bad CRC you will be working
1904 with the compiled-in default environment - *silently*!!! [This is
1905 necessary, because the first environment variable we need is the
1906 "baudrate" setting for the console - if we have a bad CRC, we don't
1907 have any device yet where we could complain.]
1909 Note: once the monitor has been relocated, then it will complain if
1910 the default environment is used; a new CRC is computed as soon as you
1911 use the "saveenv" command to store a valid environment.
1913 - CONFIG_SYS_FAULT_MII_ADDR:
1914 MII address of the PHY to check for the Ethernet link state.
1916 - CONFIG_NS16550_MIN_FUNCTIONS:
1917 Define this if you desire to only have use of the NS16550_init
1918 and NS16550_putc functions for the serial driver located at
1919 drivers/serial/ns16550.c. This option is useful for saving
1920 space for already greatly restricted images, including but not
1921 limited to NAND_SPL configurations.
1923 - CONFIG_DISPLAY_BOARDINFO
1924 Display information about the board that U-Boot is running on
1925 when U-Boot starts up. The board function checkboard() is called
1928 - CONFIG_DISPLAY_BOARDINFO_LATE
1929 Similar to the previous option, but display this information
1930 later, once stdio is running and output goes to the LCD, if
1933 Low Level (hardware related) configuration options:
1934 ---------------------------------------------------
1936 - CONFIG_SYS_CACHELINE_SIZE:
1937 Cache Line Size of the CPU.
1939 - CONFIG_SYS_CCSRBAR_DEFAULT:
1940 Default (power-on reset) physical address of CCSR on Freescale
1943 - CONFIG_SYS_CCSRBAR:
1944 Virtual address of CCSR. On a 32-bit build, this is typically
1945 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
1947 - CONFIG_SYS_CCSRBAR_PHYS:
1948 Physical address of CCSR. CCSR can be relocated to a new
1949 physical address, if desired. In this case, this macro should
1950 be set to that address. Otherwise, it should be set to the
1951 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
1952 is typically relocated on 36-bit builds. It is recommended
1953 that this macro be defined via the _HIGH and _LOW macros:
1955 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
1956 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
1958 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
1959 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
1960 either 0 (32-bit build) or 0xF (36-bit build). This macro is
1961 used in assembly code, so it must not contain typecasts or
1962 integer size suffixes (e.g. "ULL").
1964 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
1965 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
1966 used in assembly code, so it must not contain typecasts or
1967 integer size suffixes (e.g. "ULL").
1969 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
1970 DO NOT CHANGE unless you know exactly what you're
1971 doing! (11-4) [MPC8xx systems only]
1973 - CONFIG_SYS_INIT_RAM_ADDR:
1975 Start address of memory area that can be used for
1976 initial data and stack; please note that this must be
1977 writable memory that is working WITHOUT special
1978 initialization, i. e. you CANNOT use normal RAM which
1979 will become available only after programming the
1980 memory controller and running certain initialization
1983 U-Boot uses the following memory types:
1984 - MPC8xx: IMMR (internal memory of the CPU)
1986 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
1988 - CONFIG_SYS_OR_TIMING_SDRAM:
1991 - CONFIG_SYS_MAMR_PTA:
1992 periodic timer for refresh
1995 Chip has SRIO or not
1998 Board has SRIO 1 port available
2001 Board has SRIO 2 port available
2003 - CONFIG_SRIO_PCIE_BOOT_MASTER
2004 Board can support master function for Boot from SRIO and PCIE
2006 - CONFIG_SYS_SRIOn_MEM_VIRT:
2007 Virtual Address of SRIO port 'n' memory region
2009 - CONFIG_SYS_SRIOn_MEM_PHYxS:
2010 Physical Address of SRIO port 'n' memory region
2012 - CONFIG_SYS_SRIOn_MEM_SIZE:
2013 Size of SRIO port 'n' memory region
2015 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
2016 Defined to tell the NAND controller that the NAND chip is using
2018 Not all NAND drivers use this symbol.
2019 Example of drivers that use it:
2020 - drivers/mtd/nand/raw/ndfc.c
2021 - drivers/mtd/nand/raw/mxc_nand.c
2023 - CONFIG_SYS_NDFC_EBC0_CFG
2024 Sets the EBC0_CFG register for the NDFC. If not defined
2025 a default value will be used.
2028 Get DDR timing information from an I2C EEPROM. Common
2029 with pluggable memory modules such as SODIMMs
2032 I2C address of the SPD EEPROM
2034 - CONFIG_SYS_SPD_BUS_NUM
2035 If SPD EEPROM is on an I2C bus other than the first
2036 one, specify here. Note that the value must resolve
2037 to something your driver can deal with.
2039 - CONFIG_FSL_DDR_INTERACTIVE
2040 Enable interactive DDR debugging. See doc/README.fsl-ddr.
2042 - CONFIG_FSL_DDR_SYNC_REFRESH
2043 Enable sync of refresh for multiple controllers.
2045 - CONFIG_FSL_DDR_BIST
2046 Enable built-in memory test for Freescale DDR controllers.
2049 Enable RMII mode for all FECs.
2050 Note that this is a global option, we can't
2051 have one FEC in standard MII mode and another in RMII mode.
2053 - CONFIG_CRC32_VERIFY
2054 Add a verify option to the crc32 command.
2057 => crc32 -v <address> <count> <crc32>
2059 Where address/count indicate a memory area
2060 and crc32 is the correct crc32 which the
2064 Add the "loopw" memory command. This only takes effect if
2065 the memory commands are activated globally (CONFIG_CMD_MEMORY).
2067 - CONFIG_CMD_MX_CYCLIC
2068 Add the "mdc" and "mwc" memory commands. These are cyclic
2073 This command will print 4 bytes (10,11,12,13) each 500 ms.
2075 => mwc.l 100 12345678 10
2076 This command will write 12345678 to address 100 all 10 ms.
2078 This only takes effect if the memory commands are activated
2079 globally (CONFIG_CMD_MEMORY).
2082 Set when the currently-running compilation is for an artifact
2083 that will end up in the SPL (as opposed to the TPL or U-Boot
2084 proper). Code that needs stage-specific behavior should check
2088 Set when the currently-running compilation is for an artifact
2089 that will end up in the TPL (as opposed to the SPL or U-Boot
2090 proper). Code that needs stage-specific behavior should check
2093 - CONFIG_ARCH_MAP_SYSMEM
2094 Generally U-Boot (and in particular the md command) uses
2095 effective address. It is therefore not necessary to regard
2096 U-Boot address as virtual addresses that need to be translated
2097 to physical addresses. However, sandbox requires this, since
2098 it maintains its own little RAM buffer which contains all
2099 addressable memory. This option causes some memory accesses
2100 to be mapped through map_sysmem() / unmap_sysmem().
2102 - CONFIG_X86_RESET_VECTOR
2103 If defined, the x86 reset vector code is included. This is not
2104 needed when U-Boot is running from Coreboot.
2106 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
2107 Option to disable subpage write in NAND driver
2108 driver that uses this:
2109 drivers/mtd/nand/raw/davinci_nand.c
2111 Freescale QE/FMAN Firmware Support:
2112 -----------------------------------
2114 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
2115 loading of "firmware", which is encoded in the QE firmware binary format.
2116 This firmware often needs to be loaded during U-Boot booting, so macros
2117 are used to identify the storage device (NOR flash, SPI, etc) and the address
2120 - CONFIG_SYS_FMAN_FW_ADDR
2121 The address in the storage device where the FMAN microcode is located. The
2122 meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro
2125 - CONFIG_SYS_QE_FW_ADDR
2126 The address in the storage device where the QE microcode is located. The
2127 meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro
2130 - CONFIG_SYS_QE_FMAN_FW_LENGTH
2131 The maximum possible size of the firmware. The firmware binary format
2132 has a field that specifies the actual size of the firmware, but it
2133 might not be possible to read any part of the firmware unless some
2134 local storage is allocated to hold the entire firmware first.
2136 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
2137 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
2138 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
2139 virtual address in NOR flash.
2141 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
2142 Specifies that QE/FMAN firmware is located in NAND flash.
2143 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
2145 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
2146 Specifies that QE/FMAN firmware is located on the primary SD/MMC
2147 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
2149 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
2150 Specifies that QE/FMAN firmware is located in the remote (master)
2151 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
2152 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
2153 window->master inbound window->master LAW->the ucode address in
2154 master's memory space.
2156 Freescale Layerscape Management Complex Firmware Support:
2157 ---------------------------------------------------------
2158 The Freescale Layerscape Management Complex (MC) supports the loading of
2160 This firmware often needs to be loaded during U-Boot booting, so macros
2161 are used to identify the storage device (NOR flash, SPI, etc) and the address
2164 - CONFIG_FSL_MC_ENET
2165 Enable the MC driver for Layerscape SoCs.
2167 Freescale Layerscape Debug Server Support:
2168 -------------------------------------------
2169 The Freescale Layerscape Debug Server Support supports the loading of
2170 "Debug Server firmware" and triggering SP boot-rom.
2171 This firmware often needs to be loaded during U-Boot booting.
2173 - CONFIG_SYS_MC_RSV_MEM_ALIGN
2174 Define alignment of reserved memory MC requires
2179 In order to achieve reproducible builds, timestamps used in the U-Boot build
2180 process have to be set to a fixed value.
2182 This is done using the SOURCE_DATE_EPOCH environment variable.
2183 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
2184 option for U-Boot or an environment variable in U-Boot.
2186 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
2188 Building the Software:
2189 ======================
2191 Building U-Boot has been tested in several native build environments
2192 and in many different cross environments. Of course we cannot support
2193 all possibly existing versions of cross development tools in all
2194 (potentially obsolete) versions. In case of tool chain problems we
2195 recommend to use the ELDK (see https://www.denx.de/wiki/DULG/ELDK)
2196 which is extensively used to build and test U-Boot.
2198 If you are not using a native environment, it is assumed that you
2199 have GNU cross compiling tools available in your path. In this case,
2200 you must set the environment variable CROSS_COMPILE in your shell.
2201 Note that no changes to the Makefile or any other source files are
2202 necessary. For example using the ELDK on a 4xx CPU, please enter:
2204 $ CROSS_COMPILE=ppc_4xx-
2205 $ export CROSS_COMPILE
2207 U-Boot is intended to be simple to build. After installing the
2208 sources you must configure U-Boot for one specific board type. This
2213 where "NAME_defconfig" is the name of one of the existing configu-
2214 rations; see configs/*_defconfig for supported names.
2216 Note: for some boards special configuration names may exist; check if
2217 additional information is available from the board vendor; for
2218 instance, the TQM823L systems are available without (standard)
2219 or with LCD support. You can select such additional "features"
2220 when choosing the configuration, i. e.
2222 make TQM823L_defconfig
2223 - will configure for a plain TQM823L, i. e. no LCD support
2225 make TQM823L_LCD_defconfig
2226 - will configure for a TQM823L with U-Boot console on LCD
2231 Finally, type "make all", and you should get some working U-Boot
2232 images ready for download to / installation on your system:
2234 - "u-boot.bin" is a raw binary image
2235 - "u-boot" is an image in ELF binary format
2236 - "u-boot.srec" is in Motorola S-Record format
2238 By default the build is performed locally and the objects are saved
2239 in the source directory. One of the two methods can be used to change
2240 this behavior and build U-Boot to some external directory:
2242 1. Add O= to the make command line invocations:
2244 make O=/tmp/build distclean
2245 make O=/tmp/build NAME_defconfig
2246 make O=/tmp/build all
2248 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
2250 export KBUILD_OUTPUT=/tmp/build
2255 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
2258 User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by
2259 setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS.
2260 For example to treat all compiler warnings as errors:
2262 make KCFLAGS=-Werror
2264 Please be aware that the Makefiles assume you are using GNU make, so
2265 for instance on NetBSD you might need to use "gmake" instead of
2269 If the system board that you have is not listed, then you will need
2270 to port U-Boot to your hardware platform. To do this, follow these
2273 1. Create a new directory to hold your board specific code. Add any
2274 files you need. In your board directory, you will need at least
2275 the "Makefile" and a "<board>.c".
2276 2. Create a new configuration file "include/configs/<board>.h" for
2278 3. If you're porting U-Boot to a new CPU, then also create a new
2279 directory to hold your CPU specific code. Add any files you need.
2280 4. Run "make <board>_defconfig" with your new name.
2281 5. Type "make", and you should get a working "u-boot.srec" file
2282 to be installed on your target system.
2283 6. Debug and solve any problems that might arise.
2284 [Of course, this last step is much harder than it sounds.]
2287 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2288 ==============================================================
2290 If you have modified U-Boot sources (for instance added a new board
2291 or support for new devices, a new CPU, etc.) you are expected to
2292 provide feedback to the other developers. The feedback normally takes
2293 the form of a "patch", i.e. a context diff against a certain (latest
2294 official or latest in the git repository) version of U-Boot sources.
2296 But before you submit such a patch, please verify that your modifi-
2297 cation did not break existing code. At least make sure that *ALL* of
2298 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2299 just run the buildman script (tools/buildman/buildman), which will
2300 configure and build U-Boot for ALL supported system. Be warned, this
2301 will take a while. Please see the buildman README, or run 'buildman -H'
2305 See also "U-Boot Porting Guide" below.
2308 Monitor Commands - Overview:
2309 ============================
2311 go - start application at address 'addr'
2312 run - run commands in an environment variable
2313 bootm - boot application image from memory
2314 bootp - boot image via network using BootP/TFTP protocol
2315 bootz - boot zImage from memory
2316 tftpboot- boot image via network using TFTP protocol
2317 and env variables "ipaddr" and "serverip"
2318 (and eventually "gatewayip")
2319 tftpput - upload a file via network using TFTP protocol
2320 rarpboot- boot image via network using RARP/TFTP protocol
2321 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2322 loads - load S-Record file over serial line
2323 loadb - load binary file over serial line (kermit mode)
2324 loadm - load binary blob from source address to destination address
2326 mm - memory modify (auto-incrementing)
2327 nm - memory modify (constant address)
2328 mw - memory write (fill)
2331 cmp - memory compare
2332 crc32 - checksum calculation
2333 i2c - I2C sub-system
2334 sspi - SPI utility commands
2335 base - print or set address offset
2336 printenv- print environment variables
2337 pwm - control pwm channels
2338 setenv - set environment variables
2339 saveenv - save environment variables to persistent storage
2340 protect - enable or disable FLASH write protection
2341 erase - erase FLASH memory
2342 flinfo - print FLASH memory information
2343 nand - NAND memory operations (see doc/README.nand)
2344 bdinfo - print Board Info structure
2345 iminfo - print header information for application image
2346 coninfo - print console devices and informations
2347 ide - IDE sub-system
2348 loop - infinite loop on address range
2349 loopw - infinite write loop on address range
2350 mtest - simple RAM test
2351 icache - enable or disable instruction cache
2352 dcache - enable or disable data cache
2353 reset - Perform RESET of the CPU
2354 echo - echo args to console
2355 version - print monitor version
2356 help - print online help
2357 ? - alias for 'help'
2360 Monitor Commands - Detailed Description:
2361 ========================================
2365 For now: just type "help <command>".
2368 Note for Redundant Ethernet Interfaces:
2369 =======================================
2371 Some boards come with redundant Ethernet interfaces; U-Boot supports
2372 such configurations and is capable of automatic selection of a
2373 "working" interface when needed. MAC assignment works as follows:
2375 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2376 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2377 "eth1addr" (=>eth1), "eth2addr", ...
2379 If the network interface stores some valid MAC address (for instance
2380 in SROM), this is used as default address if there is NO correspon-
2381 ding setting in the environment; if the corresponding environment
2382 variable is set, this overrides the settings in the card; that means:
2384 o If the SROM has a valid MAC address, and there is no address in the
2385 environment, the SROM's address is used.
2387 o If there is no valid address in the SROM, and a definition in the
2388 environment exists, then the value from the environment variable is
2391 o If both the SROM and the environment contain a MAC address, and
2392 both addresses are the same, this MAC address is used.
2394 o If both the SROM and the environment contain a MAC address, and the
2395 addresses differ, the value from the environment is used and a
2398 o If neither SROM nor the environment contain a MAC address, an error
2399 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
2400 a random, locally-assigned MAC is used.
2402 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
2403 will be programmed into hardware as part of the initialization process. This
2404 may be skipped by setting the appropriate 'ethmacskip' environment variable.
2405 The naming convention is as follows:
2406 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
2411 U-Boot is capable of booting (and performing other auxiliary operations on)
2412 images in two formats:
2414 New uImage format (FIT)
2415 -----------------------
2417 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
2418 to Flattened Device Tree). It allows the use of images with multiple
2419 components (several kernels, ramdisks, etc.), with contents protected by
2420 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
2426 Old image format is based on binary files which can be basically anything,
2427 preceded by a special header; see the definitions in include/image.h for
2428 details; basically, the header defines the following image properties:
2430 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2431 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2432 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
2433 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, INTEGRITY).
2434 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2435 IA64, MIPS, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2436 Currently supported: ARM, Intel x86, MIPS, Nios II, PowerPC).
2437 * Compression Type (uncompressed, gzip, bzip2)
2443 The header is marked by a special Magic Number, and both the header
2444 and the data portions of the image are secured against corruption by
2451 Although U-Boot should support any OS or standalone application
2452 easily, the main focus has always been on Linux during the design of
2455 U-Boot includes many features that so far have been part of some
2456 special "boot loader" code within the Linux kernel. Also, any
2457 "initrd" images to be used are no longer part of one big Linux image;
2458 instead, kernel and "initrd" are separate images. This implementation
2459 serves several purposes:
2461 - the same features can be used for other OS or standalone
2462 applications (for instance: using compressed images to reduce the
2463 Flash memory footprint)
2465 - it becomes much easier to port new Linux kernel versions because
2466 lots of low-level, hardware dependent stuff are done by U-Boot
2468 - the same Linux kernel image can now be used with different "initrd"
2469 images; of course this also means that different kernel images can
2470 be run with the same "initrd". This makes testing easier (you don't
2471 have to build a new "zImage.initrd" Linux image when you just
2472 change a file in your "initrd"). Also, a field-upgrade of the
2473 software is easier now.
2479 Porting Linux to U-Boot based systems:
2480 ---------------------------------------
2482 U-Boot cannot save you from doing all the necessary modifications to
2483 configure the Linux device drivers for use with your target hardware
2484 (no, we don't intend to provide a full virtual machine interface to
2487 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
2489 Just make sure your machine specific header file (for instance
2490 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2491 Information structure as we define in include/asm-<arch>/u-boot.h,
2492 and make sure that your definition of IMAP_ADDR uses the same value
2493 as your U-Boot configuration in CONFIG_SYS_IMMR.
2495 Note that U-Boot now has a driver model, a unified model for drivers.
2496 If you are adding a new driver, plumb it into driver model. If there
2497 is no uclass available, you are encouraged to create one. See
2501 Configuring the Linux kernel:
2502 -----------------------------
2504 No specific requirements for U-Boot. Make sure you have some root
2505 device (initial ramdisk, NFS) for your target system.
2508 Building a Linux Image:
2509 -----------------------
2511 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2512 not used. If you use recent kernel source, a new build target
2513 "uImage" will exist which automatically builds an image usable by
2514 U-Boot. Most older kernels also have support for a "pImage" target,
2515 which was introduced for our predecessor project PPCBoot and uses a
2516 100% compatible format.
2520 make TQM850L_defconfig
2525 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2526 encapsulate a compressed Linux kernel image with header information,
2527 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2529 * build a standard "vmlinux" kernel image (in ELF binary format):
2531 * convert the kernel into a raw binary image:
2533 ${CROSS_COMPILE}-objcopy -O binary \
2534 -R .note -R .comment \
2535 -S vmlinux linux.bin
2537 * compress the binary image:
2541 * package compressed binary image for U-Boot:
2543 mkimage -A ppc -O linux -T kernel -C gzip \
2544 -a 0 -e 0 -n "Linux Kernel Image" \
2545 -d linux.bin.gz uImage
2548 The "mkimage" tool can also be used to create ramdisk images for use
2549 with U-Boot, either separated from the Linux kernel image, or
2550 combined into one file. "mkimage" encapsulates the images with a 64
2551 byte header containing information about target architecture,
2552 operating system, image type, compression method, entry points, time
2553 stamp, CRC32 checksums, etc.
2555 "mkimage" can be called in two ways: to verify existing images and
2556 print the header information, or to build new images.
2558 In the first form (with "-l" option) mkimage lists the information
2559 contained in the header of an existing U-Boot image; this includes
2560 checksum verification:
2562 tools/mkimage -l image
2563 -l ==> list image header information
2565 The second form (with "-d" option) is used to build a U-Boot image
2566 from a "data file" which is used as image payload:
2568 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2569 -n name -d data_file image
2570 -A ==> set architecture to 'arch'
2571 -O ==> set operating system to 'os'
2572 -T ==> set image type to 'type'
2573 -C ==> set compression type 'comp'
2574 -a ==> set load address to 'addr' (hex)
2575 -e ==> set entry point to 'ep' (hex)
2576 -n ==> set image name to 'name'
2577 -d ==> use image data from 'datafile'
2579 Right now, all Linux kernels for PowerPC systems use the same load
2580 address (0x00000000), but the entry point address depends on the
2583 - 2.2.x kernels have the entry point at 0x0000000C,
2584 - 2.3.x and later kernels have the entry point at 0x00000000.
2586 So a typical call to build a U-Boot image would read:
2588 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2589 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2590 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
2591 > examples/uImage.TQM850L
2592 Image Name: 2.4.4 kernel for TQM850L
2593 Created: Wed Jul 19 02:34:59 2000
2594 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2595 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2596 Load Address: 0x00000000
2597 Entry Point: 0x00000000
2599 To verify the contents of the image (or check for corruption):
2601 -> tools/mkimage -l examples/uImage.TQM850L
2602 Image Name: 2.4.4 kernel for TQM850L
2603 Created: Wed Jul 19 02:34:59 2000
2604 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2605 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2606 Load Address: 0x00000000
2607 Entry Point: 0x00000000
2609 NOTE: for embedded systems where boot time is critical you can trade
2610 speed for memory and install an UNCOMPRESSED image instead: this
2611 needs more space in Flash, but boots much faster since it does not
2612 need to be uncompressed:
2614 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
2615 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2616 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2617 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
2618 > examples/uImage.TQM850L-uncompressed
2619 Image Name: 2.4.4 kernel for TQM850L
2620 Created: Wed Jul 19 02:34:59 2000
2621 Image Type: PowerPC Linux Kernel Image (uncompressed)
2622 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2623 Load Address: 0x00000000
2624 Entry Point: 0x00000000
2627 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2628 when your kernel is intended to use an initial ramdisk:
2630 -> tools/mkimage -n 'Simple Ramdisk Image' \
2631 > -A ppc -O linux -T ramdisk -C gzip \
2632 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2633 Image Name: Simple Ramdisk Image
2634 Created: Wed Jan 12 14:01:50 2000
2635 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2636 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2637 Load Address: 0x00000000
2638 Entry Point: 0x00000000
2640 The "dumpimage" tool can be used to disassemble or list the contents of images
2641 built by mkimage. See dumpimage's help output (-h) for details.
2643 Installing a Linux Image:
2644 -------------------------
2646 To downloading a U-Boot image over the serial (console) interface,
2647 you must convert the image to S-Record format:
2649 objcopy -I binary -O srec examples/image examples/image.srec
2651 The 'objcopy' does not understand the information in the U-Boot
2652 image header, so the resulting S-Record file will be relative to
2653 address 0x00000000. To load it to a given address, you need to
2654 specify the target address as 'offset' parameter with the 'loads'
2657 Example: install the image to address 0x40100000 (which on the
2658 TQM8xxL is in the first Flash bank):
2660 => erase 40100000 401FFFFF
2666 ## Ready for S-Record download ...
2667 ~>examples/image.srec
2668 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2670 15989 15990 15991 15992
2671 [file transfer complete]
2673 ## Start Addr = 0x00000000
2676 You can check the success of the download using the 'iminfo' command;
2677 this includes a checksum verification so you can be sure no data
2678 corruption happened:
2682 ## Checking Image at 40100000 ...
2683 Image Name: 2.2.13 for initrd on TQM850L
2684 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2685 Data Size: 335725 Bytes = 327 kB = 0 MB
2686 Load Address: 00000000
2687 Entry Point: 0000000c
2688 Verifying Checksum ... OK
2694 The "bootm" command is used to boot an application that is stored in
2695 memory (RAM or Flash). In case of a Linux kernel image, the contents
2696 of the "bootargs" environment variable is passed to the kernel as
2697 parameters. You can check and modify this variable using the
2698 "printenv" and "setenv" commands:
2701 => printenv bootargs
2702 bootargs=root=/dev/ram
2704 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2706 => printenv bootargs
2707 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2710 ## Booting Linux kernel at 40020000 ...
2711 Image Name: 2.2.13 for NFS on TQM850L
2712 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2713 Data Size: 381681 Bytes = 372 kB = 0 MB
2714 Load Address: 00000000
2715 Entry Point: 0000000c
2716 Verifying Checksum ... OK
2717 Uncompressing Kernel Image ... OK
2718 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
2719 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2720 time_init: decrementer frequency = 187500000/60
2721 Calibrating delay loop... 49.77 BogoMIPS
2722 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2725 If you want to boot a Linux kernel with initial RAM disk, you pass
2726 the memory addresses of both the kernel and the initrd image (PPBCOOT
2727 format!) to the "bootm" command:
2729 => imi 40100000 40200000
2731 ## Checking Image at 40100000 ...
2732 Image Name: 2.2.13 for initrd on TQM850L
2733 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2734 Data Size: 335725 Bytes = 327 kB = 0 MB
2735 Load Address: 00000000
2736 Entry Point: 0000000c
2737 Verifying Checksum ... OK
2739 ## Checking Image at 40200000 ...
2740 Image Name: Simple Ramdisk Image
2741 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2742 Data Size: 566530 Bytes = 553 kB = 0 MB
2743 Load Address: 00000000
2744 Entry Point: 00000000
2745 Verifying Checksum ... OK
2747 => bootm 40100000 40200000
2748 ## Booting Linux kernel at 40100000 ...
2749 Image Name: 2.2.13 for initrd on TQM850L
2750 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2751 Data Size: 335725 Bytes = 327 kB = 0 MB
2752 Load Address: 00000000
2753 Entry Point: 0000000c
2754 Verifying Checksum ... OK
2755 Uncompressing Kernel Image ... OK
2756 ## Loading RAMDisk Image at 40200000 ...
2757 Image Name: Simple Ramdisk Image
2758 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2759 Data Size: 566530 Bytes = 553 kB = 0 MB
2760 Load Address: 00000000
2761 Entry Point: 00000000
2762 Verifying Checksum ... OK
2763 Loading Ramdisk ... OK
2764 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
2765 Boot arguments: root=/dev/ram
2766 time_init: decrementer frequency = 187500000/60
2767 Calibrating delay loop... 49.77 BogoMIPS
2769 RAMDISK: Compressed image found at block 0
2770 VFS: Mounted root (ext2 filesystem).
2774 Boot Linux and pass a flat device tree:
2777 First, U-Boot must be compiled with the appropriate defines. See the section
2778 titled "Linux Kernel Interface" above for a more in depth explanation. The
2779 following is an example of how to start a kernel and pass an updated
2785 oft=oftrees/mpc8540ads.dtb
2786 => tftp $oftaddr $oft
2787 Speed: 1000, full duplex
2789 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
2790 Filename 'oftrees/mpc8540ads.dtb'.
2791 Load address: 0x300000
2794 Bytes transferred = 4106 (100a hex)
2795 => tftp $loadaddr $bootfile
2796 Speed: 1000, full duplex
2798 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
2800 Load address: 0x200000
2801 Loading:############
2803 Bytes transferred = 1029407 (fb51f hex)
2808 => bootm $loadaddr - $oftaddr
2809 ## Booting image at 00200000 ...
2810 Image Name: Linux-2.6.17-dirty
2811 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2812 Data Size: 1029343 Bytes = 1005.2 kB
2813 Load Address: 00000000
2814 Entry Point: 00000000
2815 Verifying Checksum ... OK
2816 Uncompressing Kernel Image ... OK
2817 Booting using flat device tree at 0x300000
2818 Using MPC85xx ADS machine description
2819 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
2823 More About U-Boot Image Types:
2824 ------------------------------
2826 U-Boot supports the following image types:
2828 "Standalone Programs" are directly runnable in the environment
2829 provided by U-Boot; it is expected that (if they behave
2830 well) you can continue to work in U-Boot after return from
2831 the Standalone Program.
2832 "OS Kernel Images" are usually images of some Embedded OS which
2833 will take over control completely. Usually these programs
2834 will install their own set of exception handlers, device
2835 drivers, set up the MMU, etc. - this means, that you cannot
2836 expect to re-enter U-Boot except by resetting the CPU.
2837 "RAMDisk Images" are more or less just data blocks, and their
2838 parameters (address, size) are passed to an OS kernel that is
2840 "Multi-File Images" contain several images, typically an OS
2841 (Linux) kernel image and one or more data images like
2842 RAMDisks. This construct is useful for instance when you want
2843 to boot over the network using BOOTP etc., where the boot
2844 server provides just a single image file, but you want to get
2845 for instance an OS kernel and a RAMDisk image.
2847 "Multi-File Images" start with a list of image sizes, each
2848 image size (in bytes) specified by an "uint32_t" in network
2849 byte order. This list is terminated by an "(uint32_t)0".
2850 Immediately after the terminating 0 follow the images, one by
2851 one, all aligned on "uint32_t" boundaries (size rounded up to
2852 a multiple of 4 bytes).
2854 "Firmware Images" are binary images containing firmware (like
2855 U-Boot or FPGA images) which usually will be programmed to
2858 "Script files" are command sequences that will be executed by
2859 U-Boot's command interpreter; this feature is especially
2860 useful when you configure U-Boot to use a real shell (hush)
2861 as command interpreter.
2863 Booting the Linux zImage:
2864 -------------------------
2866 On some platforms, it's possible to boot Linux zImage. This is done
2867 using the "bootz" command. The syntax of "bootz" command is the same
2868 as the syntax of "bootm" command.
2870 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
2871 kernel with raw initrd images. The syntax is slightly different, the
2872 address of the initrd must be augmented by it's size, in the following
2873 format: "<initrd addres>:<initrd size>".
2879 One of the features of U-Boot is that you can dynamically load and
2880 run "standalone" applications, which can use some resources of
2881 U-Boot like console I/O functions or interrupt services.
2883 Two simple examples are included with the sources:
2888 'examples/hello_world.c' contains a small "Hello World" Demo
2889 application; it is automatically compiled when you build U-Boot.
2890 It's configured to run at address 0x00040004, so you can play with it
2894 ## Ready for S-Record download ...
2895 ~>examples/hello_world.srec
2896 1 2 3 4 5 6 7 8 9 10 11 ...
2897 [file transfer complete]
2899 ## Start Addr = 0x00040004
2901 => go 40004 Hello World! This is a test.
2902 ## Starting application at 0x00040004 ...
2913 Hit any key to exit ...
2915 ## Application terminated, rc = 0x0
2917 Another example, which demonstrates how to register a CPM interrupt
2918 handler with the U-Boot code, can be found in 'examples/timer.c'.
2919 Here, a CPM timer is set up to generate an interrupt every second.
2920 The interrupt service routine is trivial, just printing a '.'
2921 character, but this is just a demo program. The application can be
2922 controlled by the following keys:
2924 ? - print current values og the CPM Timer registers
2925 b - enable interrupts and start timer
2926 e - stop timer and disable interrupts
2927 q - quit application
2930 ## Ready for S-Record download ...
2931 ~>examples/timer.srec
2932 1 2 3 4 5 6 7 8 9 10 11 ...
2933 [file transfer complete]
2935 ## Start Addr = 0x00040004
2938 ## Starting application at 0x00040004 ...
2941 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2944 [q, b, e, ?] Set interval 1000000 us
2947 [q, b, e, ?] ........
2948 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2951 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2954 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2957 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2959 [q, b, e, ?] ...Stopping timer
2961 [q, b, e, ?] ## Application terminated, rc = 0x0
2967 Over time, many people have reported problems when trying to use the
2968 "minicom" terminal emulation program for serial download. I (wd)
2969 consider minicom to be broken, and recommend not to use it. Under
2970 Unix, I recommend to use C-Kermit for general purpose use (and
2971 especially for kermit binary protocol download ("loadb" command), and
2972 use "cu" for S-Record download ("loads" command). See
2973 https://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
2974 for help with kermit.
2977 Nevertheless, if you absolutely want to use it try adding this
2978 configuration to your "File transfer protocols" section:
2980 Name Program Name U/D FullScr IO-Red. Multi
2981 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
2982 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
2988 Starting at version 0.9.2, U-Boot supports NetBSD both as host
2989 (build U-Boot) and target system (boots NetBSD/mpc8xx).
2991 Building requires a cross environment; it is known to work on
2992 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2993 need gmake since the Makefiles are not compatible with BSD make).
2994 Note that the cross-powerpc package does not install include files;
2995 attempting to build U-Boot will fail because <machine/ansi.h> is
2996 missing. This file has to be installed and patched manually:
2998 # cd /usr/pkg/cross/powerpc-netbsd/include
3000 # ln -s powerpc machine
3001 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3002 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3004 Native builds *don't* work due to incompatibilities between native
3005 and U-Boot include files.
3007 Booting assumes that (the first part of) the image booted is a
3008 stage-2 loader which in turn loads and then invokes the kernel
3009 proper. Loader sources will eventually appear in the NetBSD source
3010 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3011 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3014 Implementation Internals:
3015 =========================
3017 The following is not intended to be a complete description of every
3018 implementation detail. However, it should help to understand the
3019 inner workings of U-Boot and make it easier to port it to custom
3023 Initial Stack, Global Data:
3024 ---------------------------
3026 The implementation of U-Boot is complicated by the fact that U-Boot
3027 starts running out of ROM (flash memory), usually without access to
3028 system RAM (because the memory controller is not initialized yet).
3029 This means that we don't have writable Data or BSS segments, and BSS
3030 is not initialized as zero. To be able to get a C environment working
3031 at all, we have to allocate at least a minimal stack. Implementation
3032 options for this are defined and restricted by the CPU used: Some CPU
3033 models provide on-chip memory (like the IMMR area on MPC8xx and
3034 MPC826x processors), on others (parts of) the data cache can be
3035 locked as (mis-) used as memory, etc.
3037 Chris Hallinan posted a good summary of these issues to the
3038 U-Boot mailing list:
3040 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3041 From: "Chris Hallinan" <clh@net1plus.com>
3042 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3045 Correct me if I'm wrong, folks, but the way I understand it
3046 is this: Using DCACHE as initial RAM for Stack, etc, does not
3047 require any physical RAM backing up the cache. The cleverness
3048 is that the cache is being used as a temporary supply of
3049 necessary storage before the SDRAM controller is setup. It's
3050 beyond the scope of this list to explain the details, but you
3051 can see how this works by studying the cache architecture and
3052 operation in the architecture and processor-specific manuals.
3054 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3055 is another option for the system designer to use as an
3056 initial stack/RAM area prior to SDRAM being available. Either
3057 option should work for you. Using CS 4 should be fine if your
3058 board designers haven't used it for something that would
3059 cause you grief during the initial boot! It is frequently not
3062 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
3063 with your processor/board/system design. The default value
3064 you will find in any recent u-boot distribution in
3065 walnut.h should work for you. I'd set it to a value larger
3066 than your SDRAM module. If you have a 64MB SDRAM module, set
3067 it above 400_0000. Just make sure your board has no resources
3068 that are supposed to respond to that address! That code in
3069 start.S has been around a while and should work as is when
3070 you get the config right.
3075 It is essential to remember this, since it has some impact on the C
3076 code for the initialization procedures:
3078 * Initialized global data (data segment) is read-only. Do not attempt
3081 * Do not use any uninitialized global data (or implicitly initialized
3082 as zero data - BSS segment) at all - this is undefined, initiali-
3083 zation is performed later (when relocating to RAM).
3085 * Stack space is very limited. Avoid big data buffers or things like
3088 Having only the stack as writable memory limits means we cannot use
3089 normal global data to share information between the code. But it
3090 turned out that the implementation of U-Boot can be greatly
3091 simplified by making a global data structure (gd_t) available to all
3092 functions. We could pass a pointer to this data as argument to _all_
3093 functions, but this would bloat the code. Instead we use a feature of
3094 the GCC compiler (Global Register Variables) to share the data: we
3095 place a pointer (gd) to the global data into a register which we
3096 reserve for this purpose.
3098 When choosing a register for such a purpose we are restricted by the
3099 relevant (E)ABI specifications for the current architecture, and by
3100 GCC's implementation.
3102 For PowerPC, the following registers have specific use:
3104 R2: reserved for system use
3105 R3-R4: parameter passing and return values
3106 R5-R10: parameter passing
3107 R13: small data area pointer
3111 (U-Boot also uses R12 as internal GOT pointer. r12
3112 is a volatile register so r12 needs to be reset when
3113 going back and forth between asm and C)
3115 ==> U-Boot will use R2 to hold a pointer to the global data
3117 Note: on PPC, we could use a static initializer (since the
3118 address of the global data structure is known at compile time),
3119 but it turned out that reserving a register results in somewhat
3120 smaller code - although the code savings are not that big (on
3121 average for all boards 752 bytes for the whole U-Boot image,
3122 624 text + 127 data).
3124 On ARM, the following registers are used:
3126 R0: function argument word/integer result
3127 R1-R3: function argument word
3128 R9: platform specific
3129 R10: stack limit (used only if stack checking is enabled)
3130 R11: argument (frame) pointer
3131 R12: temporary workspace
3134 R15: program counter
3136 ==> U-Boot will use R9 to hold a pointer to the global data
3138 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
3140 On Nios II, the ABI is documented here:
3141 https://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
3143 ==> U-Boot will use gp to hold a pointer to the global data
3145 Note: on Nios II, we give "-G0" option to gcc and don't use gp
3146 to access small data sections, so gp is free.
3148 On RISC-V, the following registers are used:
3150 x0: hard-wired zero (zero)
3151 x1: return address (ra)
3152 x2: stack pointer (sp)
3153 x3: global pointer (gp)
3154 x4: thread pointer (tp)
3155 x5: link register (t0)
3156 x8: frame pointer (fp)
3157 x10-x11: arguments/return values (a0-1)
3158 x12-x17: arguments (a2-7)
3159 x28-31: temporaries (t3-6)
3160 pc: program counter (pc)
3162 ==> U-Boot will use gp to hold a pointer to the global data
3167 U-Boot runs in system state and uses physical addresses, i.e. the
3168 MMU is not used either for address mapping nor for memory protection.
3170 The available memory is mapped to fixed addresses using the memory
3171 controller. In this process, a contiguous block is formed for each
3172 memory type (Flash, SDRAM, SRAM), even when it consists of several
3173 physical memory banks.
3175 U-Boot is installed in the first 128 kB of the first Flash bank (on
3176 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3177 booting and sizing and initializing DRAM, the code relocates itself
3178 to the upper end of DRAM. Immediately below the U-Boot code some
3179 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
3180 configuration setting]. Below that, a structure with global Board
3181 Info data is placed, followed by the stack (growing downward).
3183 Additionally, some exception handler code is copied to the low 8 kB
3184 of DRAM (0x00000000 ... 0x00001FFF).
3186 So a typical memory configuration with 16 MB of DRAM could look like
3189 0x0000 0000 Exception Vector code
3192 0x0000 2000 Free for Application Use
3198 0x00FB FF20 Monitor Stack (Growing downward)
3199 0x00FB FFAC Board Info Data and permanent copy of global data
3200 0x00FC 0000 Malloc Arena
3203 0x00FE 0000 RAM Copy of Monitor Code
3204 ... eventually: LCD or video framebuffer
3205 ... eventually: pRAM (Protected RAM - unchanged by reset)
3206 0x00FF FFFF [End of RAM]
3209 System Initialization:
3210 ----------------------
3212 In the reset configuration, U-Boot starts at the reset entry point
3213 (on most PowerPC systems at address 0x00000100). Because of the reset
3214 configuration for CS0# this is a mirror of the on board Flash memory.
3215 To be able to re-map memory U-Boot then jumps to its link address.
3216 To be able to implement the initialization code in C, a (small!)
3217 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3218 which provide such a feature like), or in a locked part of the data
3219 cache. After that, U-Boot initializes the CPU core, the caches and
3222 Next, all (potentially) available memory banks are mapped using a
3223 preliminary mapping. For example, we put them on 512 MB boundaries
3224 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3225 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3226 programmed for SDRAM access. Using the temporary configuration, a
3227 simple memory test is run that determines the size of the SDRAM
3230 When there is more than one SDRAM bank, and the banks are of
3231 different size, the largest is mapped first. For equal size, the first
3232 bank (CS2#) is mapped first. The first mapping is always for address
3233 0x00000000, with any additional banks following immediately to create
3234 contiguous memory starting from 0.
3236 Then, the monitor installs itself at the upper end of the SDRAM area
3237 and allocates memory for use by malloc() and for the global Board
3238 Info data; also, the exception vector code is copied to the low RAM
3239 pages, and the final stack is set up.
3241 Only after this relocation will you have a "normal" C environment;
3242 until that you are restricted in several ways, mostly because you are
3243 running from ROM, and because the code will have to be relocated to a
3247 U-Boot Porting Guide:
3248 ----------------------
3250 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3254 int main(int argc, char *argv[])
3256 sighandler_t no_more_time;
3258 signal(SIGALRM, no_more_time);
3259 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
3261 if (available_money > available_manpower) {
3262 Pay consultant to port U-Boot;
3266 Download latest U-Boot source;
3268 Subscribe to u-boot mailing list;
3271 email("Hi, I am new to U-Boot, how do I get started?");
3274 Read the README file in the top level directory;
3275 Read https://www.denx.de/wiki/bin/view/DULG/Manual;
3276 Read applicable doc/README.*;
3277 Read the source, Luke;
3278 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
3281 if (available_money > toLocalCurrency ($2500))
3284 Add a lot of aggravation and time;
3286 if (a similar board exists) { /* hopefully... */
3287 cp -a board/<similar> board/<myboard>
3288 cp include/configs/<similar>.h include/configs/<myboard>.h
3290 Create your own board support subdirectory;
3291 Create your own board include/configs/<myboard>.h file;
3293 Edit new board/<myboard> files
3294 Edit new include/configs/<myboard>.h
3299 Add / modify source code;
3303 email("Hi, I am having problems...");
3305 Send patch file to the U-Boot email list;
3306 if (reasonable critiques)
3307 Incorporate improvements from email list code review;
3309 Defend code as written;
3315 void no_more_time (int sig)
3324 All contributions to U-Boot should conform to the Linux kernel
3325 coding style; see the kernel coding style guide at
3326 https://www.kernel.org/doc/html/latest/process/coding-style.html, and the
3327 script "scripts/Lindent" in your Linux kernel source directory.
3329 Source files originating from a different project (for example the
3330 MTD subsystem) are generally exempt from these guidelines and are not
3331 reformatted to ease subsequent migration to newer versions of those
3334 Please note that U-Boot is implemented in C (and to some small parts in
3335 Assembler); no C++ is used, so please do not use C++ style comments (//)
3338 Please also stick to the following formatting rules:
3339 - remove any trailing white space
3340 - use TAB characters for indentation and vertical alignment, not spaces
3341 - make sure NOT to use DOS '\r\n' line feeds
3342 - do not add more than 2 consecutive empty lines to source files
3343 - do not add trailing empty lines to source files
3345 Submissions which do not conform to the standards may be returned
3346 with a request to reformat the changes.
3352 Since the number of patches for U-Boot is growing, we need to
3353 establish some rules. Submissions which do not conform to these rules
3354 may be rejected, even when they contain important and valuable stuff.
3356 Please see https://www.denx.de/wiki/U-Boot/Patches for details.
3358 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
3359 see https://lists.denx.de/listinfo/u-boot
3361 When you send a patch, please include the following information with
3364 * For bug fixes: a description of the bug and how your patch fixes
3365 this bug. Please try to include a way of demonstrating that the
3366 patch actually fixes something.
3368 * For new features: a description of the feature and your
3371 * For major contributions, add a MAINTAINERS file with your
3372 information and associated file and directory references.
3374 * When you add support for a new board, don't forget to add a
3375 maintainer e-mail address to the boards.cfg file, too.
3377 * If your patch adds new configuration options, don't forget to
3378 document these in the README file.
3380 * The patch itself. If you are using git (which is *strongly*
3381 recommended) you can easily generate the patch using the
3382 "git format-patch". If you then use "git send-email" to send it to
3383 the U-Boot mailing list, you will avoid most of the common problems
3384 with some other mail clients.
3386 If you cannot use git, use "diff -purN OLD NEW". If your version of
3387 diff does not support these options, then get the latest version of
3390 The current directory when running this command shall be the parent
3391 directory of the U-Boot source tree (i. e. please make sure that
3392 your patch includes sufficient directory information for the
3395 We prefer patches as plain text. MIME attachments are discouraged,
3396 and compressed attachments must not be used.
3398 * If one logical set of modifications affects or creates several
3399 files, all these changes shall be submitted in a SINGLE patch file.
3401 * Changesets that contain different, unrelated modifications shall be
3402 submitted as SEPARATE patches, one patch per changeset.
3407 * Before sending the patch, run the buildman script on your patched
3408 source tree and make sure that no errors or warnings are reported
3409 for any of the boards.
3411 * Keep your modifications to the necessary minimum: A patch
3412 containing several unrelated changes or arbitrary reformats will be
3413 returned with a request to re-formatting / split it.
3415 * If you modify existing code, make sure that your new code does not
3416 add to the memory footprint of the code ;-) Small is beautiful!
3417 When adding new features, these should compile conditionally only
3418 (using #ifdef), and the resulting code with the new feature
3419 disabled must not need more memory than the old code without your
3422 * Remember that there is a size limit of 100 kB per message on the
3423 u-boot mailing list. Bigger patches will be moderated. If they are
3424 reasonable and not too big, they will be acknowledged. But patches
3425 bigger than the size limit should be avoided.