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_PROG_FEEDBACK
1335 Enable printing of hash marks during FPGA configuration.
1337 CONFIG_SYS_FPGA_CHECK_BUSY
1339 Enable checks on FPGA configuration interface busy
1340 status by the configuration function. This option
1341 will require a board or device specific function to
1346 If defined, a function that provides delays in the FPGA
1347 configuration driver.
1349 CONFIG_SYS_FPGA_CHECK_CTRLC
1350 Allow Control-C to interrupt FPGA configuration
1352 CONFIG_SYS_FPGA_CHECK_ERROR
1354 Check for configuration errors during FPGA bitfile
1355 loading. For example, abort during Virtex II
1356 configuration if the INIT_B line goes low (which
1357 indicated a CRC error).
1359 CONFIG_SYS_FPGA_WAIT_INIT
1361 Maximum time to wait for the INIT_B line to de-assert
1362 after PROB_B has been de-asserted during a Virtex II
1363 FPGA configuration sequence. The default time is 500
1366 CONFIG_SYS_FPGA_WAIT_BUSY
1368 Maximum time to wait for BUSY to de-assert during
1369 Virtex II FPGA configuration. The default is 5 ms.
1371 CONFIG_SYS_FPGA_WAIT_CONFIG
1373 Time to wait after FPGA configuration. The default is
1376 - Vendor Parameter Protection:
1378 U-Boot considers the values of the environment
1379 variables "serial#" (Board Serial Number) and
1380 "ethaddr" (Ethernet Address) to be parameters that
1381 are set once by the board vendor / manufacturer, and
1382 protects these variables from casual modification by
1383 the user. Once set, these variables are read-only,
1384 and write or delete attempts are rejected. You can
1385 change this behaviour:
1387 If CONFIG_ENV_OVERWRITE is #defined in your config
1388 file, the write protection for vendor parameters is
1389 completely disabled. Anybody can change or delete
1392 Alternatively, if you define _both_ an ethaddr in the
1393 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1394 Ethernet address is installed in the environment,
1395 which can be changed exactly ONCE by the user. [The
1396 serial# is unaffected by this, i. e. it remains
1399 The same can be accomplished in a more flexible way
1400 for any variable by configuring the type of access
1401 to allow for those variables in the ".flags" variable
1402 or define CONFIG_ENV_FLAGS_LIST_STATIC.
1407 Define this variable to enable the reservation of
1408 "protected RAM", i. e. RAM which is not overwritten
1409 by U-Boot. Define CONFIG_PRAM to hold the number of
1410 kB you want to reserve for pRAM. You can overwrite
1411 this default value by defining an environment
1412 variable "pram" to the number of kB you want to
1413 reserve. Note that the board info structure will
1414 still show the full amount of RAM. If pRAM is
1415 reserved, a new environment variable "mem" will
1416 automatically be defined to hold the amount of
1417 remaining RAM in a form that can be passed as boot
1418 argument to Linux, for instance like that:
1420 setenv bootargs ... mem=\${mem}
1423 This way you can tell Linux not to use this memory,
1424 either, which results in a memory region that will
1425 not be affected by reboots.
1427 *WARNING* If your board configuration uses automatic
1428 detection of the RAM size, you must make sure that
1429 this memory test is non-destructive. So far, the
1430 following board configurations are known to be
1433 IVMS8, IVML24, SPD8xx,
1434 HERMES, IP860, RPXlite, LWMON,
1440 In the current implementation, the local variables
1441 space and global environment variables space are
1442 separated. Local variables are those you define by
1443 simply typing `name=value'. To access a local
1444 variable later on, you have write `$name' or
1445 `${name}'; to execute the contents of a variable
1446 directly type `$name' at the command prompt.
1448 Global environment variables are those you use
1449 setenv/printenv to work with. To run a command stored
1450 in such a variable, you need to use the run command,
1451 and you must not use the '$' sign to access them.
1453 To store commands and special characters in a
1454 variable, please use double quotation marks
1455 surrounding the whole text of the variable, instead
1456 of the backslashes before semicolons and special
1459 - Default Environment:
1460 CONFIG_EXTRA_ENV_SETTINGS
1462 Define this to contain any number of null terminated
1463 strings (variable = value pairs) that will be part of
1464 the default environment compiled into the boot image.
1466 For example, place something like this in your
1467 board's config file:
1469 #define CONFIG_EXTRA_ENV_SETTINGS \
1473 Warning: This method is based on knowledge about the
1474 internal format how the environment is stored by the
1475 U-Boot code. This is NOT an official, exported
1476 interface! Although it is unlikely that this format
1477 will change soon, there is no guarantee either.
1478 You better know what you are doing here.
1480 Note: overly (ab)use of the default environment is
1481 discouraged. Make sure to check other ways to preset
1482 the environment like the "source" command or the
1485 CONFIG_DELAY_ENVIRONMENT
1487 Normally the environment is loaded when the board is
1488 initialised so that it is available to U-Boot. This inhibits
1489 that so that the environment is not available until
1490 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
1491 this is instead controlled by the value of
1492 /config/load-environment.
1494 CONFIG_STANDALONE_LOAD_ADDR
1496 This option defines a board specific value for the
1497 address where standalone program gets loaded, thus
1498 overwriting the architecture dependent default
1501 - Automatic software updates via TFTP server
1503 CONFIG_UPDATE_TFTP_CNT_MAX
1504 CONFIG_UPDATE_TFTP_MSEC_MAX
1506 These options enable and control the auto-update feature;
1507 for a more detailed description refer to doc/README.update.
1509 - MTD Support (mtdparts command, UBI support)
1510 CONFIG_MTD_UBI_WL_THRESHOLD
1511 This parameter defines the maximum difference between the highest
1512 erase counter value and the lowest erase counter value of eraseblocks
1513 of UBI devices. When this threshold is exceeded, UBI starts performing
1514 wear leveling by means of moving data from eraseblock with low erase
1515 counter to eraseblocks with high erase counter.
1517 The default value should be OK for SLC NAND flashes, NOR flashes and
1518 other flashes which have eraseblock life-cycle 100000 or more.
1519 However, in case of MLC NAND flashes which typically have eraseblock
1520 life-cycle less than 10000, the threshold should be lessened (e.g.,
1521 to 128 or 256, although it does not have to be power of 2).
1525 CONFIG_MTD_UBI_BEB_LIMIT
1526 This option specifies the maximum bad physical eraseblocks UBI
1527 expects on the MTD device (per 1024 eraseblocks). If the
1528 underlying flash does not admit of bad eraseblocks (e.g. NOR
1529 flash), this value is ignored.
1531 NAND datasheets often specify the minimum and maximum NVM
1532 (Number of Valid Blocks) for the flashes' endurance lifetime.
1533 The maximum expected bad eraseblocks per 1024 eraseblocks
1534 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
1535 which gives 20 for most NANDs (MaxNVB is basically the total
1536 count of eraseblocks on the chip).
1538 To put it differently, if this value is 20, UBI will try to
1539 reserve about 1.9% of physical eraseblocks for bad blocks
1540 handling. And that will be 1.9% of eraseblocks on the entire
1541 NAND chip, not just the MTD partition UBI attaches. This means
1542 that if you have, say, a NAND flash chip admits maximum 40 bad
1543 eraseblocks, and it is split on two MTD partitions of the same
1544 size, UBI will reserve 40 eraseblocks when attaching a
1549 CONFIG_MTD_UBI_FASTMAP
1550 Fastmap is a mechanism which allows attaching an UBI device
1551 in nearly constant time. Instead of scanning the whole MTD device it
1552 only has to locate a checkpoint (called fastmap) on the device.
1553 The on-flash fastmap contains all information needed to attach
1554 the device. Using fastmap makes only sense on large devices where
1555 attaching by scanning takes long. UBI will not automatically install
1556 a fastmap on old images, but you can set the UBI parameter
1557 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
1558 that fastmap-enabled images are still usable with UBI implementations
1559 without fastmap support. On typical flash devices the whole fastmap
1560 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
1562 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
1563 Set this parameter to enable fastmap automatically on images
1567 CONFIG_MTD_UBI_FM_DEBUG
1568 Enable UBI fastmap debug
1573 Enable building of SPL globally.
1575 CONFIG_SPL_PANIC_ON_RAW_IMAGE
1576 When defined, SPL will panic() if the image it has
1577 loaded does not have a signature.
1578 Defining this is useful when code which loads images
1579 in SPL cannot guarantee that absolutely all read errors
1581 An example is the LPC32XX MLC NAND driver, which will
1582 consider that a completely unreadable NAND block is bad,
1583 and thus should be skipped silently.
1585 CONFIG_SPL_DISPLAY_PRINT
1586 For ARM, enable an optional function to print more information
1587 about the running system.
1589 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
1590 Set this for NAND SPL on PPC mpc83xx targets, so that
1591 start.S waits for the rest of the SPL to load before
1592 continuing (the hardware starts execution after just
1593 loading the first page rather than the full 4K).
1596 Support for a lightweight UBI (fastmap) scanner and
1599 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
1600 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
1601 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
1602 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
1603 CONFIG_SYS_NAND_ECCBYTES
1604 Defines the size and behavior of the NAND that SPL uses
1607 CONFIG_SYS_NAND_U_BOOT_DST
1608 Location in memory to load U-Boot to
1610 CONFIG_SYS_NAND_U_BOOT_SIZE
1611 Size of image to load
1613 CONFIG_SYS_NAND_U_BOOT_START
1614 Entry point in loaded image to jump to
1616 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
1617 Define this if you need to first read the OOB and then the
1618 data. This is used, for example, on davinci platforms.
1620 CONFIG_SPL_RAM_DEVICE
1621 Support for running image already present in ram, in SPL binary
1623 CONFIG_SPL_FIT_PRINT
1624 Printing information about a FIT image adds quite a bit of
1625 code to SPL. So this is normally disabled in SPL. Use this
1626 option to re-enable it. This will affect the output of the
1627 bootm command when booting a FIT image.
1629 - Interrupt support (PPC):
1631 There are common interrupt_init() and timer_interrupt()
1632 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1633 for CPU specific initialization. interrupt_init_cpu()
1634 should set decrementer_count to appropriate value. If
1635 CPU resets decrementer automatically after interrupt
1636 (ppc4xx) it should set decrementer_count to zero.
1637 timer_interrupt() calls timer_interrupt_cpu() for CPU
1638 specific handling. If board has watchdog / status_led
1639 / other_activity_monitor it works automatically from
1640 general timer_interrupt().
1643 Board initialization settings:
1644 ------------------------------
1646 During Initialization u-boot calls a number of board specific functions
1647 to allow the preparation of board specific prerequisites, e.g. pin setup
1648 before drivers are initialized. To enable these callbacks the
1649 following configuration macros have to be defined. Currently this is
1650 architecture specific, so please check arch/your_architecture/lib/board.c
1651 typically in board_init_f() and board_init_r().
1653 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
1654 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
1655 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
1657 Configuration Settings:
1658 -----------------------
1660 - MEM_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
1661 Optionally it can be defined to support 64-bit memory commands.
1663 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
1664 undefine this when you're short of memory.
1666 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
1667 width of the commands listed in the 'help' command output.
1669 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
1670 prompt for user input.
1672 - CONFIG_SYS_BAUDRATE_TABLE:
1673 List of legal baudrate settings for this board.
1675 - CONFIG_SYS_MEM_RESERVE_SECURE
1676 Only implemented for ARMv8 for now.
1677 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
1678 is substracted from total RAM and won't be reported to OS.
1679 This memory can be used as secure memory. A variable
1680 gd->arch.secure_ram is used to track the location. In systems
1681 the RAM base is not zero, or RAM is divided into banks,
1682 this variable needs to be recalcuated to get the address.
1684 - CONFIG_SYS_LOADS_BAUD_CHANGE:
1685 Enable temporary baudrate change while serial download
1687 - CONFIG_SYS_SDRAM_BASE:
1688 Physical start address of SDRAM. _Must_ be 0 here.
1690 - CONFIG_SYS_FLASH_BASE:
1691 Physical start address of Flash memory.
1693 - CONFIG_SYS_MONITOR_LEN:
1694 Size of memory reserved for monitor code, used to
1695 determine _at_compile_time_ (!) if the environment is
1696 embedded within the U-Boot image, or in a separate
1699 - CONFIG_SYS_MALLOC_LEN:
1700 Size of DRAM reserved for malloc() use.
1702 - CONFIG_SYS_MALLOC_F_LEN
1703 Size of the malloc() pool for use before relocation. If
1704 this is defined, then a very simple malloc() implementation
1705 will become available before relocation. The address is just
1706 below the global data, and the stack is moved down to make
1709 This feature allocates regions with increasing addresses
1710 within the region. calloc() is supported, but realloc()
1711 is not available. free() is supported but does nothing.
1712 The memory will be freed (or in fact just forgotten) when
1713 U-Boot relocates itself.
1715 - CONFIG_SYS_MALLOC_SIMPLE
1716 Provides a simple and small malloc() and calloc() for those
1717 boards which do not use the full malloc in SPL (which is
1718 enabled with CONFIG_SYS_SPL_MALLOC).
1720 - CONFIG_SYS_NONCACHED_MEMORY:
1721 Size of non-cached memory area. This area of memory will be
1722 typically located right below the malloc() area and mapped
1723 uncached in the MMU. This is useful for drivers that would
1724 otherwise require a lot of explicit cache maintenance. For
1725 some drivers it's also impossible to properly maintain the
1726 cache. For example if the regions that need to be flushed
1727 are not a multiple of the cache-line size, *and* padding
1728 cannot be allocated between the regions to align them (i.e.
1729 if the HW requires a contiguous array of regions, and the
1730 size of each region is not cache-aligned), then a flush of
1731 one region may result in overwriting data that hardware has
1732 written to another region in the same cache-line. This can
1733 happen for example in network drivers where descriptors for
1734 buffers are typically smaller than the CPU cache-line (e.g.
1735 16 bytes vs. 32 or 64 bytes).
1737 Non-cached memory is only supported on 32-bit ARM at present.
1739 - CONFIG_SYS_BOOTM_LEN:
1740 Normally compressed uImages are limited to an
1741 uncompressed size of 8 MBytes. If this is not enough,
1742 you can define CONFIG_SYS_BOOTM_LEN in your board config file
1743 to adjust this setting to your needs.
1745 - CONFIG_SYS_BOOTMAPSZ:
1746 Maximum size of memory mapped by the startup code of
1747 the Linux kernel; all data that must be processed by
1748 the Linux kernel (bd_info, boot arguments, FDT blob if
1749 used) must be put below this limit, unless "bootm_low"
1750 environment variable is defined and non-zero. In such case
1751 all data for the Linux kernel must be between "bootm_low"
1752 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
1753 variable "bootm_mapsize" will override the value of
1754 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
1755 then the value in "bootm_size" will be used instead.
1757 - CONFIG_SYS_BOOT_GET_CMDLINE:
1758 Enables allocating and saving kernel cmdline in space between
1759 "bootm_low" and "bootm_low" + BOOTMAPSZ.
1761 - CONFIG_SYS_BOOT_GET_KBD:
1762 Enables allocating and saving a kernel copy of the bd_info in
1763 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
1765 - CONFIG_SYS_MAX_FLASH_SECT:
1766 Max number of sectors on a Flash chip
1768 - CONFIG_SYS_FLASH_ERASE_TOUT:
1769 Timeout for Flash erase operations (in ms)
1771 - CONFIG_SYS_FLASH_WRITE_TOUT:
1772 Timeout for Flash write operations (in ms)
1774 - CONFIG_SYS_FLASH_LOCK_TOUT
1775 Timeout for Flash set sector lock bit operation (in ms)
1777 - CONFIG_SYS_FLASH_UNLOCK_TOUT
1778 Timeout for Flash clear lock bits operation (in ms)
1780 - CONFIG_SYS_FLASH_PROTECTION
1781 If defined, hardware flash sectors protection is used
1782 instead of U-Boot software protection.
1784 - CONFIG_SYS_DIRECT_FLASH_TFTP:
1786 Enable TFTP transfers directly to flash memory;
1787 without this option such a download has to be
1788 performed in two steps: (1) download to RAM, and (2)
1789 copy from RAM to flash.
1791 The two-step approach is usually more reliable, since
1792 you can check if the download worked before you erase
1793 the flash, but in some situations (when system RAM is
1794 too limited to allow for a temporary copy of the
1795 downloaded image) this option may be very useful.
1797 - CONFIG_SYS_FLASH_CFI:
1798 Define if the flash driver uses extra elements in the
1799 common flash structure for storing flash geometry.
1801 - CONFIG_FLASH_CFI_DRIVER
1802 This option also enables the building of the cfi_flash driver
1803 in the drivers directory
1805 - CONFIG_FLASH_CFI_MTD
1806 This option enables the building of the cfi_mtd driver
1807 in the drivers directory. The driver exports CFI flash
1810 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
1811 Use buffered writes to flash.
1813 - CONFIG_FLASH_SPANSION_S29WS_N
1814 s29ws-n MirrorBit flash has non-standard addresses for buffered
1817 - CONFIG_SYS_FLASH_QUIET_TEST
1818 If this option is defined, the common CFI flash doesn't
1819 print it's warning upon not recognized FLASH banks. This
1820 is useful, if some of the configured banks are only
1821 optionally available.
1823 - CONFIG_FLASH_SHOW_PROGRESS
1824 If defined (must be an integer), print out countdown
1825 digits and dots. Recommended value: 45 (9..1) for 80
1826 column displays, 15 (3..1) for 40 column displays.
1828 - CONFIG_FLASH_VERIFY
1829 If defined, the content of the flash (destination) is compared
1830 against the source after the write operation. An error message
1831 will be printed when the contents are not identical.
1832 Please note that this option is useless in nearly all cases,
1833 since such flash programming errors usually are detected earlier
1834 while unprotecting/erasing/programming. Please only enable
1835 this option if you really know what you are doing.
1837 - CONFIG_ENV_FLAGS_LIST_DEFAULT
1838 - CONFIG_ENV_FLAGS_LIST_STATIC
1839 Enable validation of the values given to environment variables when
1840 calling env set. Variables can be restricted to only decimal,
1841 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
1842 the variables can also be restricted to IP address or MAC address.
1844 The format of the list is:
1845 type_attribute = [s|d|x|b|i|m]
1846 access_attribute = [a|r|o|c]
1847 attributes = type_attribute[access_attribute]
1848 entry = variable_name[:attributes]
1851 The type attributes are:
1852 s - String (default)
1855 b - Boolean ([1yYtT|0nNfF])
1859 The access attributes are:
1865 - CONFIG_ENV_FLAGS_LIST_DEFAULT
1866 Define this to a list (string) to define the ".flags"
1867 environment variable in the default or embedded environment.
1869 - CONFIG_ENV_FLAGS_LIST_STATIC
1870 Define this to a list (string) to define validation that
1871 should be done if an entry is not found in the ".flags"
1872 environment variable. To override a setting in the static
1873 list, simply add an entry for the same variable name to the
1876 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
1877 regular expression. This allows multiple variables to define the same
1878 flags without explicitly listing them for each variable.
1880 The following definitions that deal with the placement and management
1881 of environment data (variable area); in general, we support the
1882 following configurations:
1884 - CONFIG_BUILD_ENVCRC:
1886 Builds up envcrc with the target environment so that external utils
1887 may easily extract it and embed it in final U-Boot images.
1889 BE CAREFUL! The first access to the environment happens quite early
1890 in U-Boot initialization (when we try to get the setting of for the
1891 console baudrate). You *MUST* have mapped your NVRAM area then, or
1894 Please note that even with NVRAM we still use a copy of the
1895 environment in RAM: we could work on NVRAM directly, but we want to
1896 keep settings there always unmodified except somebody uses "saveenv"
1897 to save the current settings.
1899 BE CAREFUL! For some special cases, the local device can not use
1900 "saveenv" command. For example, the local device will get the
1901 environment stored in a remote NOR flash by SRIO or PCIE link,
1902 but it can not erase, write this NOR flash by SRIO or PCIE interface.
1904 - CONFIG_NAND_ENV_DST
1906 Defines address in RAM to which the nand_spl code should copy the
1907 environment. If redundant environment is used, it will be copied to
1908 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
1910 Please note that the environment is read-only until the monitor
1911 has been relocated to RAM and a RAM copy of the environment has been
1912 created; also, when using EEPROM you will have to use env_get_f()
1913 until then to read environment variables.
1915 The environment is protected by a CRC32 checksum. Before the monitor
1916 is relocated into RAM, as a result of a bad CRC you will be working
1917 with the compiled-in default environment - *silently*!!! [This is
1918 necessary, because the first environment variable we need is the
1919 "baudrate" setting for the console - if we have a bad CRC, we don't
1920 have any device yet where we could complain.]
1922 Note: once the monitor has been relocated, then it will complain if
1923 the default environment is used; a new CRC is computed as soon as you
1924 use the "saveenv" command to store a valid environment.
1926 - CONFIG_SYS_FAULT_MII_ADDR:
1927 MII address of the PHY to check for the Ethernet link state.
1929 - CONFIG_NS16550_MIN_FUNCTIONS:
1930 Define this if you desire to only have use of the NS16550_init
1931 and NS16550_putc functions for the serial driver located at
1932 drivers/serial/ns16550.c. This option is useful for saving
1933 space for already greatly restricted images, including but not
1934 limited to NAND_SPL configurations.
1936 - CONFIG_DISPLAY_BOARDINFO
1937 Display information about the board that U-Boot is running on
1938 when U-Boot starts up. The board function checkboard() is called
1941 - CONFIG_DISPLAY_BOARDINFO_LATE
1942 Similar to the previous option, but display this information
1943 later, once stdio is running and output goes to the LCD, if
1946 Low Level (hardware related) configuration options:
1947 ---------------------------------------------------
1949 - CONFIG_SYS_CACHELINE_SIZE:
1950 Cache Line Size of the CPU.
1952 - CONFIG_SYS_CCSRBAR_DEFAULT:
1953 Default (power-on reset) physical address of CCSR on Freescale
1956 - CONFIG_SYS_CCSRBAR:
1957 Virtual address of CCSR. On a 32-bit build, this is typically
1958 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
1960 - CONFIG_SYS_CCSRBAR_PHYS:
1961 Physical address of CCSR. CCSR can be relocated to a new
1962 physical address, if desired. In this case, this macro should
1963 be set to that address. Otherwise, it should be set to the
1964 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
1965 is typically relocated on 36-bit builds. It is recommended
1966 that this macro be defined via the _HIGH and _LOW macros:
1968 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
1969 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
1971 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
1972 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
1973 either 0 (32-bit build) or 0xF (36-bit build). This macro is
1974 used in assembly code, so it must not contain typecasts or
1975 integer size suffixes (e.g. "ULL").
1977 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
1978 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
1979 used in assembly code, so it must not contain typecasts or
1980 integer size suffixes (e.g. "ULL").
1982 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
1983 DO NOT CHANGE unless you know exactly what you're
1984 doing! (11-4) [MPC8xx systems only]
1986 - CONFIG_SYS_INIT_RAM_ADDR:
1988 Start address of memory area that can be used for
1989 initial data and stack; please note that this must be
1990 writable memory that is working WITHOUT special
1991 initialization, i. e. you CANNOT use normal RAM which
1992 will become available only after programming the
1993 memory controller and running certain initialization
1996 U-Boot uses the following memory types:
1997 - MPC8xx: IMMR (internal memory of the CPU)
1999 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
2001 - CONFIG_SYS_OR_TIMING_SDRAM:
2004 - CONFIG_SYS_MAMR_PTA:
2005 periodic timer for refresh
2008 Chip has SRIO or not
2011 Board has SRIO 1 port available
2014 Board has SRIO 2 port available
2016 - CONFIG_SRIO_PCIE_BOOT_MASTER
2017 Board can support master function for Boot from SRIO and PCIE
2019 - CONFIG_SYS_SRIOn_MEM_VIRT:
2020 Virtual Address of SRIO port 'n' memory region
2022 - CONFIG_SYS_SRIOn_MEM_PHYxS:
2023 Physical Address of SRIO port 'n' memory region
2025 - CONFIG_SYS_SRIOn_MEM_SIZE:
2026 Size of SRIO port 'n' memory region
2028 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
2029 Defined to tell the NAND controller that the NAND chip is using
2031 Not all NAND drivers use this symbol.
2032 Example of drivers that use it:
2033 - drivers/mtd/nand/raw/ndfc.c
2034 - drivers/mtd/nand/raw/mxc_nand.c
2036 - CONFIG_SYS_NDFC_EBC0_CFG
2037 Sets the EBC0_CFG register for the NDFC. If not defined
2038 a default value will be used.
2041 Get DDR timing information from an I2C EEPROM. Common
2042 with pluggable memory modules such as SODIMMs
2045 I2C address of the SPD EEPROM
2047 - CONFIG_SYS_SPD_BUS_NUM
2048 If SPD EEPROM is on an I2C bus other than the first
2049 one, specify here. Note that the value must resolve
2050 to something your driver can deal with.
2052 - CONFIG_FSL_DDR_INTERACTIVE
2053 Enable interactive DDR debugging. See doc/README.fsl-ddr.
2055 - CONFIG_FSL_DDR_SYNC_REFRESH
2056 Enable sync of refresh for multiple controllers.
2058 - CONFIG_FSL_DDR_BIST
2059 Enable built-in memory test for Freescale DDR controllers.
2062 Enable RMII mode for all FECs.
2063 Note that this is a global option, we can't
2064 have one FEC in standard MII mode and another in RMII mode.
2066 - CONFIG_CRC32_VERIFY
2067 Add a verify option to the crc32 command.
2070 => crc32 -v <address> <count> <crc32>
2072 Where address/count indicate a memory area
2073 and crc32 is the correct crc32 which the
2077 Add the "loopw" memory command. This only takes effect if
2078 the memory commands are activated globally (CONFIG_CMD_MEMORY).
2080 - CONFIG_CMD_MX_CYCLIC
2081 Add the "mdc" and "mwc" memory commands. These are cyclic
2086 This command will print 4 bytes (10,11,12,13) each 500 ms.
2088 => mwc.l 100 12345678 10
2089 This command will write 12345678 to address 100 all 10 ms.
2091 This only takes effect if the memory commands are activated
2092 globally (CONFIG_CMD_MEMORY).
2095 Set when the currently-running compilation is for an artifact
2096 that will end up in the SPL (as opposed to the TPL or U-Boot
2097 proper). Code that needs stage-specific behavior should check
2101 Set when the currently-running compilation is for an artifact
2102 that will end up in the TPL (as opposed to the SPL or U-Boot
2103 proper). Code that needs stage-specific behavior should check
2106 - CONFIG_ARCH_MAP_SYSMEM
2107 Generally U-Boot (and in particular the md command) uses
2108 effective address. It is therefore not necessary to regard
2109 U-Boot address as virtual addresses that need to be translated
2110 to physical addresses. However, sandbox requires this, since
2111 it maintains its own little RAM buffer which contains all
2112 addressable memory. This option causes some memory accesses
2113 to be mapped through map_sysmem() / unmap_sysmem().
2115 - CONFIG_X86_RESET_VECTOR
2116 If defined, the x86 reset vector code is included. This is not
2117 needed when U-Boot is running from Coreboot.
2119 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
2120 Option to disable subpage write in NAND driver
2121 driver that uses this:
2122 drivers/mtd/nand/raw/davinci_nand.c
2124 Freescale QE/FMAN Firmware Support:
2125 -----------------------------------
2127 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
2128 loading of "firmware", which is encoded in the QE firmware binary format.
2129 This firmware often needs to be loaded during U-Boot booting, so macros
2130 are used to identify the storage device (NOR flash, SPI, etc) and the address
2133 - CONFIG_SYS_FMAN_FW_ADDR
2134 The address in the storage device where the FMAN microcode is located. The
2135 meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro
2138 - CONFIG_SYS_QE_FW_ADDR
2139 The address in the storage device where the QE microcode is located. The
2140 meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro
2143 - CONFIG_SYS_QE_FMAN_FW_LENGTH
2144 The maximum possible size of the firmware. The firmware binary format
2145 has a field that specifies the actual size of the firmware, but it
2146 might not be possible to read any part of the firmware unless some
2147 local storage is allocated to hold the entire firmware first.
2149 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
2150 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
2151 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
2152 virtual address in NOR flash.
2154 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
2155 Specifies that QE/FMAN firmware is located in NAND flash.
2156 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
2158 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
2159 Specifies that QE/FMAN firmware is located on the primary SD/MMC
2160 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
2162 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
2163 Specifies that QE/FMAN firmware is located in the remote (master)
2164 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
2165 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
2166 window->master inbound window->master LAW->the ucode address in
2167 master's memory space.
2169 Freescale Layerscape Management Complex Firmware Support:
2170 ---------------------------------------------------------
2171 The Freescale Layerscape Management Complex (MC) supports the loading of
2173 This firmware often needs to be loaded during U-Boot booting, so macros
2174 are used to identify the storage device (NOR flash, SPI, etc) and the address
2177 - CONFIG_FSL_MC_ENET
2178 Enable the MC driver for Layerscape SoCs.
2180 Freescale Layerscape Debug Server Support:
2181 -------------------------------------------
2182 The Freescale Layerscape Debug Server Support supports the loading of
2183 "Debug Server firmware" and triggering SP boot-rom.
2184 This firmware often needs to be loaded during U-Boot booting.
2186 - CONFIG_SYS_MC_RSV_MEM_ALIGN
2187 Define alignment of reserved memory MC requires
2192 In order to achieve reproducible builds, timestamps used in the U-Boot build
2193 process have to be set to a fixed value.
2195 This is done using the SOURCE_DATE_EPOCH environment variable.
2196 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
2197 option for U-Boot or an environment variable in U-Boot.
2199 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
2201 Building the Software:
2202 ======================
2204 Building U-Boot has been tested in several native build environments
2205 and in many different cross environments. Of course we cannot support
2206 all possibly existing versions of cross development tools in all
2207 (potentially obsolete) versions. In case of tool chain problems we
2208 recommend to use the ELDK (see https://www.denx.de/wiki/DULG/ELDK)
2209 which is extensively used to build and test U-Boot.
2211 If you are not using a native environment, it is assumed that you
2212 have GNU cross compiling tools available in your path. In this case,
2213 you must set the environment variable CROSS_COMPILE in your shell.
2214 Note that no changes to the Makefile or any other source files are
2215 necessary. For example using the ELDK on a 4xx CPU, please enter:
2217 $ CROSS_COMPILE=ppc_4xx-
2218 $ export CROSS_COMPILE
2220 U-Boot is intended to be simple to build. After installing the
2221 sources you must configure U-Boot for one specific board type. This
2226 where "NAME_defconfig" is the name of one of the existing configu-
2227 rations; see configs/*_defconfig for supported names.
2229 Note: for some boards special configuration names may exist; check if
2230 additional information is available from the board vendor; for
2231 instance, the TQM823L systems are available without (standard)
2232 or with LCD support. You can select such additional "features"
2233 when choosing the configuration, i. e.
2235 make TQM823L_defconfig
2236 - will configure for a plain TQM823L, i. e. no LCD support
2238 make TQM823L_LCD_defconfig
2239 - will configure for a TQM823L with U-Boot console on LCD
2244 Finally, type "make all", and you should get some working U-Boot
2245 images ready for download to / installation on your system:
2247 - "u-boot.bin" is a raw binary image
2248 - "u-boot" is an image in ELF binary format
2249 - "u-boot.srec" is in Motorola S-Record format
2251 By default the build is performed locally and the objects are saved
2252 in the source directory. One of the two methods can be used to change
2253 this behavior and build U-Boot to some external directory:
2255 1. Add O= to the make command line invocations:
2257 make O=/tmp/build distclean
2258 make O=/tmp/build NAME_defconfig
2259 make O=/tmp/build all
2261 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
2263 export KBUILD_OUTPUT=/tmp/build
2268 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
2271 User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by
2272 setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS.
2273 For example to treat all compiler warnings as errors:
2275 make KCFLAGS=-Werror
2277 Please be aware that the Makefiles assume you are using GNU make, so
2278 for instance on NetBSD you might need to use "gmake" instead of
2282 If the system board that you have is not listed, then you will need
2283 to port U-Boot to your hardware platform. To do this, follow these
2286 1. Create a new directory to hold your board specific code. Add any
2287 files you need. In your board directory, you will need at least
2288 the "Makefile" and a "<board>.c".
2289 2. Create a new configuration file "include/configs/<board>.h" for
2291 3. If you're porting U-Boot to a new CPU, then also create a new
2292 directory to hold your CPU specific code. Add any files you need.
2293 4. Run "make <board>_defconfig" with your new name.
2294 5. Type "make", and you should get a working "u-boot.srec" file
2295 to be installed on your target system.
2296 6. Debug and solve any problems that might arise.
2297 [Of course, this last step is much harder than it sounds.]
2300 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2301 ==============================================================
2303 If you have modified U-Boot sources (for instance added a new board
2304 or support for new devices, a new CPU, etc.) you are expected to
2305 provide feedback to the other developers. The feedback normally takes
2306 the form of a "patch", i.e. a context diff against a certain (latest
2307 official or latest in the git repository) version of U-Boot sources.
2309 But before you submit such a patch, please verify that your modifi-
2310 cation did not break existing code. At least make sure that *ALL* of
2311 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2312 just run the buildman script (tools/buildman/buildman), which will
2313 configure and build U-Boot for ALL supported system. Be warned, this
2314 will take a while. Please see the buildman README, or run 'buildman -H'
2318 See also "U-Boot Porting Guide" below.
2321 Monitor Commands - Overview:
2322 ============================
2324 go - start application at address 'addr'
2325 run - run commands in an environment variable
2326 bootm - boot application image from memory
2327 bootp - boot image via network using BootP/TFTP protocol
2328 bootz - boot zImage from memory
2329 tftpboot- boot image via network using TFTP protocol
2330 and env variables "ipaddr" and "serverip"
2331 (and eventually "gatewayip")
2332 tftpput - upload a file via network using TFTP protocol
2333 rarpboot- boot image via network using RARP/TFTP protocol
2334 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2335 loads - load S-Record file over serial line
2336 loadb - load binary file over serial line (kermit mode)
2337 loadm - load binary blob from source address to destination address
2339 mm - memory modify (auto-incrementing)
2340 nm - memory modify (constant address)
2341 mw - memory write (fill)
2344 cmp - memory compare
2345 crc32 - checksum calculation
2346 i2c - I2C sub-system
2347 sspi - SPI utility commands
2348 base - print or set address offset
2349 printenv- print environment variables
2350 pwm - control pwm channels
2351 setenv - set environment variables
2352 saveenv - save environment variables to persistent storage
2353 protect - enable or disable FLASH write protection
2354 erase - erase FLASH memory
2355 flinfo - print FLASH memory information
2356 nand - NAND memory operations (see doc/README.nand)
2357 bdinfo - print Board Info structure
2358 iminfo - print header information for application image
2359 coninfo - print console devices and informations
2360 ide - IDE sub-system
2361 loop - infinite loop on address range
2362 loopw - infinite write loop on address range
2363 mtest - simple RAM test
2364 icache - enable or disable instruction cache
2365 dcache - enable or disable data cache
2366 reset - Perform RESET of the CPU
2367 echo - echo args to console
2368 version - print monitor version
2369 help - print online help
2370 ? - alias for 'help'
2373 Monitor Commands - Detailed Description:
2374 ========================================
2378 For now: just type "help <command>".
2381 Note for Redundant Ethernet Interfaces:
2382 =======================================
2384 Some boards come with redundant Ethernet interfaces; U-Boot supports
2385 such configurations and is capable of automatic selection of a
2386 "working" interface when needed. MAC assignment works as follows:
2388 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2389 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2390 "eth1addr" (=>eth1), "eth2addr", ...
2392 If the network interface stores some valid MAC address (for instance
2393 in SROM), this is used as default address if there is NO correspon-
2394 ding setting in the environment; if the corresponding environment
2395 variable is set, this overrides the settings in the card; that means:
2397 o If the SROM has a valid MAC address, and there is no address in the
2398 environment, the SROM's address is used.
2400 o If there is no valid address in the SROM, and a definition in the
2401 environment exists, then the value from the environment variable is
2404 o If both the SROM and the environment contain a MAC address, and
2405 both addresses are the same, this MAC address is used.
2407 o If both the SROM and the environment contain a MAC address, and the
2408 addresses differ, the value from the environment is used and a
2411 o If neither SROM nor the environment contain a MAC address, an error
2412 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
2413 a random, locally-assigned MAC is used.
2415 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
2416 will be programmed into hardware as part of the initialization process. This
2417 may be skipped by setting the appropriate 'ethmacskip' environment variable.
2418 The naming convention is as follows:
2419 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
2424 U-Boot is capable of booting (and performing other auxiliary operations on)
2425 images in two formats:
2427 New uImage format (FIT)
2428 -----------------------
2430 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
2431 to Flattened Device Tree). It allows the use of images with multiple
2432 components (several kernels, ramdisks, etc.), with contents protected by
2433 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
2439 Old image format is based on binary files which can be basically anything,
2440 preceded by a special header; see the definitions in include/image.h for
2441 details; basically, the header defines the following image properties:
2443 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2444 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2445 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
2446 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, INTEGRITY).
2447 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2448 IA64, MIPS, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2449 Currently supported: ARM, Intel x86, MIPS, Nios II, PowerPC).
2450 * Compression Type (uncompressed, gzip, bzip2)
2456 The header is marked by a special Magic Number, and both the header
2457 and the data portions of the image are secured against corruption by
2464 Although U-Boot should support any OS or standalone application
2465 easily, the main focus has always been on Linux during the design of
2468 U-Boot includes many features that so far have been part of some
2469 special "boot loader" code within the Linux kernel. Also, any
2470 "initrd" images to be used are no longer part of one big Linux image;
2471 instead, kernel and "initrd" are separate images. This implementation
2472 serves several purposes:
2474 - the same features can be used for other OS or standalone
2475 applications (for instance: using compressed images to reduce the
2476 Flash memory footprint)
2478 - it becomes much easier to port new Linux kernel versions because
2479 lots of low-level, hardware dependent stuff are done by U-Boot
2481 - the same Linux kernel image can now be used with different "initrd"
2482 images; of course this also means that different kernel images can
2483 be run with the same "initrd". This makes testing easier (you don't
2484 have to build a new "zImage.initrd" Linux image when you just
2485 change a file in your "initrd"). Also, a field-upgrade of the
2486 software is easier now.
2492 Porting Linux to U-Boot based systems:
2493 ---------------------------------------
2495 U-Boot cannot save you from doing all the necessary modifications to
2496 configure the Linux device drivers for use with your target hardware
2497 (no, we don't intend to provide a full virtual machine interface to
2500 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
2502 Just make sure your machine specific header file (for instance
2503 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2504 Information structure as we define in include/asm-<arch>/u-boot.h,
2505 and make sure that your definition of IMAP_ADDR uses the same value
2506 as your U-Boot configuration in CONFIG_SYS_IMMR.
2508 Note that U-Boot now has a driver model, a unified model for drivers.
2509 If you are adding a new driver, plumb it into driver model. If there
2510 is no uclass available, you are encouraged to create one. See
2514 Configuring the Linux kernel:
2515 -----------------------------
2517 No specific requirements for U-Boot. Make sure you have some root
2518 device (initial ramdisk, NFS) for your target system.
2521 Building a Linux Image:
2522 -----------------------
2524 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2525 not used. If you use recent kernel source, a new build target
2526 "uImage" will exist which automatically builds an image usable by
2527 U-Boot. Most older kernels also have support for a "pImage" target,
2528 which was introduced for our predecessor project PPCBoot and uses a
2529 100% compatible format.
2533 make TQM850L_defconfig
2538 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2539 encapsulate a compressed Linux kernel image with header information,
2540 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2542 * build a standard "vmlinux" kernel image (in ELF binary format):
2544 * convert the kernel into a raw binary image:
2546 ${CROSS_COMPILE}-objcopy -O binary \
2547 -R .note -R .comment \
2548 -S vmlinux linux.bin
2550 * compress the binary image:
2554 * package compressed binary image for U-Boot:
2556 mkimage -A ppc -O linux -T kernel -C gzip \
2557 -a 0 -e 0 -n "Linux Kernel Image" \
2558 -d linux.bin.gz uImage
2561 The "mkimage" tool can also be used to create ramdisk images for use
2562 with U-Boot, either separated from the Linux kernel image, or
2563 combined into one file. "mkimage" encapsulates the images with a 64
2564 byte header containing information about target architecture,
2565 operating system, image type, compression method, entry points, time
2566 stamp, CRC32 checksums, etc.
2568 "mkimage" can be called in two ways: to verify existing images and
2569 print the header information, or to build new images.
2571 In the first form (with "-l" option) mkimage lists the information
2572 contained in the header of an existing U-Boot image; this includes
2573 checksum verification:
2575 tools/mkimage -l image
2576 -l ==> list image header information
2578 The second form (with "-d" option) is used to build a U-Boot image
2579 from a "data file" which is used as image payload:
2581 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2582 -n name -d data_file image
2583 -A ==> set architecture to 'arch'
2584 -O ==> set operating system to 'os'
2585 -T ==> set image type to 'type'
2586 -C ==> set compression type 'comp'
2587 -a ==> set load address to 'addr' (hex)
2588 -e ==> set entry point to 'ep' (hex)
2589 -n ==> set image name to 'name'
2590 -d ==> use image data from 'datafile'
2592 Right now, all Linux kernels for PowerPC systems use the same load
2593 address (0x00000000), but the entry point address depends on the
2596 - 2.2.x kernels have the entry point at 0x0000000C,
2597 - 2.3.x and later kernels have the entry point at 0x00000000.
2599 So a typical call to build a U-Boot image would read:
2601 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2602 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2603 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
2604 > examples/uImage.TQM850L
2605 Image Name: 2.4.4 kernel for TQM850L
2606 Created: Wed Jul 19 02:34:59 2000
2607 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2608 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2609 Load Address: 0x00000000
2610 Entry Point: 0x00000000
2612 To verify the contents of the image (or check for corruption):
2614 -> tools/mkimage -l examples/uImage.TQM850L
2615 Image Name: 2.4.4 kernel for TQM850L
2616 Created: Wed Jul 19 02:34:59 2000
2617 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2618 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2619 Load Address: 0x00000000
2620 Entry Point: 0x00000000
2622 NOTE: for embedded systems where boot time is critical you can trade
2623 speed for memory and install an UNCOMPRESSED image instead: this
2624 needs more space in Flash, but boots much faster since it does not
2625 need to be uncompressed:
2627 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
2628 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2629 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2630 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
2631 > examples/uImage.TQM850L-uncompressed
2632 Image Name: 2.4.4 kernel for TQM850L
2633 Created: Wed Jul 19 02:34:59 2000
2634 Image Type: PowerPC Linux Kernel Image (uncompressed)
2635 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2636 Load Address: 0x00000000
2637 Entry Point: 0x00000000
2640 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2641 when your kernel is intended to use an initial ramdisk:
2643 -> tools/mkimage -n 'Simple Ramdisk Image' \
2644 > -A ppc -O linux -T ramdisk -C gzip \
2645 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2646 Image Name: Simple Ramdisk Image
2647 Created: Wed Jan 12 14:01:50 2000
2648 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2649 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2650 Load Address: 0x00000000
2651 Entry Point: 0x00000000
2653 The "dumpimage" tool can be used to disassemble or list the contents of images
2654 built by mkimage. See dumpimage's help output (-h) for details.
2656 Installing a Linux Image:
2657 -------------------------
2659 To downloading a U-Boot image over the serial (console) interface,
2660 you must convert the image to S-Record format:
2662 objcopy -I binary -O srec examples/image examples/image.srec
2664 The 'objcopy' does not understand the information in the U-Boot
2665 image header, so the resulting S-Record file will be relative to
2666 address 0x00000000. To load it to a given address, you need to
2667 specify the target address as 'offset' parameter with the 'loads'
2670 Example: install the image to address 0x40100000 (which on the
2671 TQM8xxL is in the first Flash bank):
2673 => erase 40100000 401FFFFF
2679 ## Ready for S-Record download ...
2680 ~>examples/image.srec
2681 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2683 15989 15990 15991 15992
2684 [file transfer complete]
2686 ## Start Addr = 0x00000000
2689 You can check the success of the download using the 'iminfo' command;
2690 this includes a checksum verification so you can be sure no data
2691 corruption happened:
2695 ## Checking Image at 40100000 ...
2696 Image Name: 2.2.13 for initrd on TQM850L
2697 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2698 Data Size: 335725 Bytes = 327 kB = 0 MB
2699 Load Address: 00000000
2700 Entry Point: 0000000c
2701 Verifying Checksum ... OK
2707 The "bootm" command is used to boot an application that is stored in
2708 memory (RAM or Flash). In case of a Linux kernel image, the contents
2709 of the "bootargs" environment variable is passed to the kernel as
2710 parameters. You can check and modify this variable using the
2711 "printenv" and "setenv" commands:
2714 => printenv bootargs
2715 bootargs=root=/dev/ram
2717 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2719 => printenv bootargs
2720 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2723 ## Booting Linux kernel at 40020000 ...
2724 Image Name: 2.2.13 for NFS on TQM850L
2725 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2726 Data Size: 381681 Bytes = 372 kB = 0 MB
2727 Load Address: 00000000
2728 Entry Point: 0000000c
2729 Verifying Checksum ... OK
2730 Uncompressing Kernel Image ... OK
2731 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
2732 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2733 time_init: decrementer frequency = 187500000/60
2734 Calibrating delay loop... 49.77 BogoMIPS
2735 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2738 If you want to boot a Linux kernel with initial RAM disk, you pass
2739 the memory addresses of both the kernel and the initrd image (PPBCOOT
2740 format!) to the "bootm" command:
2742 => imi 40100000 40200000
2744 ## Checking Image at 40100000 ...
2745 Image Name: 2.2.13 for initrd on TQM850L
2746 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2747 Data Size: 335725 Bytes = 327 kB = 0 MB
2748 Load Address: 00000000
2749 Entry Point: 0000000c
2750 Verifying Checksum ... OK
2752 ## Checking Image at 40200000 ...
2753 Image Name: Simple Ramdisk Image
2754 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2755 Data Size: 566530 Bytes = 553 kB = 0 MB
2756 Load Address: 00000000
2757 Entry Point: 00000000
2758 Verifying Checksum ... OK
2760 => bootm 40100000 40200000
2761 ## Booting Linux kernel at 40100000 ...
2762 Image Name: 2.2.13 for initrd on TQM850L
2763 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2764 Data Size: 335725 Bytes = 327 kB = 0 MB
2765 Load Address: 00000000
2766 Entry Point: 0000000c
2767 Verifying Checksum ... OK
2768 Uncompressing Kernel Image ... OK
2769 ## Loading RAMDisk Image at 40200000 ...
2770 Image Name: Simple Ramdisk Image
2771 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2772 Data Size: 566530 Bytes = 553 kB = 0 MB
2773 Load Address: 00000000
2774 Entry Point: 00000000
2775 Verifying Checksum ... OK
2776 Loading Ramdisk ... OK
2777 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
2778 Boot arguments: root=/dev/ram
2779 time_init: decrementer frequency = 187500000/60
2780 Calibrating delay loop... 49.77 BogoMIPS
2782 RAMDISK: Compressed image found at block 0
2783 VFS: Mounted root (ext2 filesystem).
2787 Boot Linux and pass a flat device tree:
2790 First, U-Boot must be compiled with the appropriate defines. See the section
2791 titled "Linux Kernel Interface" above for a more in depth explanation. The
2792 following is an example of how to start a kernel and pass an updated
2798 oft=oftrees/mpc8540ads.dtb
2799 => tftp $oftaddr $oft
2800 Speed: 1000, full duplex
2802 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
2803 Filename 'oftrees/mpc8540ads.dtb'.
2804 Load address: 0x300000
2807 Bytes transferred = 4106 (100a hex)
2808 => tftp $loadaddr $bootfile
2809 Speed: 1000, full duplex
2811 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
2813 Load address: 0x200000
2814 Loading:############
2816 Bytes transferred = 1029407 (fb51f hex)
2821 => bootm $loadaddr - $oftaddr
2822 ## Booting image at 00200000 ...
2823 Image Name: Linux-2.6.17-dirty
2824 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2825 Data Size: 1029343 Bytes = 1005.2 kB
2826 Load Address: 00000000
2827 Entry Point: 00000000
2828 Verifying Checksum ... OK
2829 Uncompressing Kernel Image ... OK
2830 Booting using flat device tree at 0x300000
2831 Using MPC85xx ADS machine description
2832 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
2836 More About U-Boot Image Types:
2837 ------------------------------
2839 U-Boot supports the following image types:
2841 "Standalone Programs" are directly runnable in the environment
2842 provided by U-Boot; it is expected that (if they behave
2843 well) you can continue to work in U-Boot after return from
2844 the Standalone Program.
2845 "OS Kernel Images" are usually images of some Embedded OS which
2846 will take over control completely. Usually these programs
2847 will install their own set of exception handlers, device
2848 drivers, set up the MMU, etc. - this means, that you cannot
2849 expect to re-enter U-Boot except by resetting the CPU.
2850 "RAMDisk Images" are more or less just data blocks, and their
2851 parameters (address, size) are passed to an OS kernel that is
2853 "Multi-File Images" contain several images, typically an OS
2854 (Linux) kernel image and one or more data images like
2855 RAMDisks. This construct is useful for instance when you want
2856 to boot over the network using BOOTP etc., where the boot
2857 server provides just a single image file, but you want to get
2858 for instance an OS kernel and a RAMDisk image.
2860 "Multi-File Images" start with a list of image sizes, each
2861 image size (in bytes) specified by an "uint32_t" in network
2862 byte order. This list is terminated by an "(uint32_t)0".
2863 Immediately after the terminating 0 follow the images, one by
2864 one, all aligned on "uint32_t" boundaries (size rounded up to
2865 a multiple of 4 bytes).
2867 "Firmware Images" are binary images containing firmware (like
2868 U-Boot or FPGA images) which usually will be programmed to
2871 "Script files" are command sequences that will be executed by
2872 U-Boot's command interpreter; this feature is especially
2873 useful when you configure U-Boot to use a real shell (hush)
2874 as command interpreter.
2876 Booting the Linux zImage:
2877 -------------------------
2879 On some platforms, it's possible to boot Linux zImage. This is done
2880 using the "bootz" command. The syntax of "bootz" command is the same
2881 as the syntax of "bootm" command.
2883 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
2884 kernel with raw initrd images. The syntax is slightly different, the
2885 address of the initrd must be augmented by it's size, in the following
2886 format: "<initrd addres>:<initrd size>".
2892 One of the features of U-Boot is that you can dynamically load and
2893 run "standalone" applications, which can use some resources of
2894 U-Boot like console I/O functions or interrupt services.
2896 Two simple examples are included with the sources:
2901 'examples/hello_world.c' contains a small "Hello World" Demo
2902 application; it is automatically compiled when you build U-Boot.
2903 It's configured to run at address 0x00040004, so you can play with it
2907 ## Ready for S-Record download ...
2908 ~>examples/hello_world.srec
2909 1 2 3 4 5 6 7 8 9 10 11 ...
2910 [file transfer complete]
2912 ## Start Addr = 0x00040004
2914 => go 40004 Hello World! This is a test.
2915 ## Starting application at 0x00040004 ...
2926 Hit any key to exit ...
2928 ## Application terminated, rc = 0x0
2930 Another example, which demonstrates how to register a CPM interrupt
2931 handler with the U-Boot code, can be found in 'examples/timer.c'.
2932 Here, a CPM timer is set up to generate an interrupt every second.
2933 The interrupt service routine is trivial, just printing a '.'
2934 character, but this is just a demo program. The application can be
2935 controlled by the following keys:
2937 ? - print current values og the CPM Timer registers
2938 b - enable interrupts and start timer
2939 e - stop timer and disable interrupts
2940 q - quit application
2943 ## Ready for S-Record download ...
2944 ~>examples/timer.srec
2945 1 2 3 4 5 6 7 8 9 10 11 ...
2946 [file transfer complete]
2948 ## Start Addr = 0x00040004
2951 ## Starting application at 0x00040004 ...
2954 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2957 [q, b, e, ?] Set interval 1000000 us
2960 [q, b, e, ?] ........
2961 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2964 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2967 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2970 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2972 [q, b, e, ?] ...Stopping timer
2974 [q, b, e, ?] ## Application terminated, rc = 0x0
2980 Over time, many people have reported problems when trying to use the
2981 "minicom" terminal emulation program for serial download. I (wd)
2982 consider minicom to be broken, and recommend not to use it. Under
2983 Unix, I recommend to use C-Kermit for general purpose use (and
2984 especially for kermit binary protocol download ("loadb" command), and
2985 use "cu" for S-Record download ("loads" command). See
2986 https://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
2987 for help with kermit.
2990 Nevertheless, if you absolutely want to use it try adding this
2991 configuration to your "File transfer protocols" section:
2993 Name Program Name U/D FullScr IO-Red. Multi
2994 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
2995 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3001 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3002 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3004 Building requires a cross environment; it is known to work on
3005 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3006 need gmake since the Makefiles are not compatible with BSD make).
3007 Note that the cross-powerpc package does not install include files;
3008 attempting to build U-Boot will fail because <machine/ansi.h> is
3009 missing. This file has to be installed and patched manually:
3011 # cd /usr/pkg/cross/powerpc-netbsd/include
3013 # ln -s powerpc machine
3014 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3015 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3017 Native builds *don't* work due to incompatibilities between native
3018 and U-Boot include files.
3020 Booting assumes that (the first part of) the image booted is a
3021 stage-2 loader which in turn loads and then invokes the kernel
3022 proper. Loader sources will eventually appear in the NetBSD source
3023 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3024 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3027 Implementation Internals:
3028 =========================
3030 The following is not intended to be a complete description of every
3031 implementation detail. However, it should help to understand the
3032 inner workings of U-Boot and make it easier to port it to custom
3036 Initial Stack, Global Data:
3037 ---------------------------
3039 The implementation of U-Boot is complicated by the fact that U-Boot
3040 starts running out of ROM (flash memory), usually without access to
3041 system RAM (because the memory controller is not initialized yet).
3042 This means that we don't have writable Data or BSS segments, and BSS
3043 is not initialized as zero. To be able to get a C environment working
3044 at all, we have to allocate at least a minimal stack. Implementation
3045 options for this are defined and restricted by the CPU used: Some CPU
3046 models provide on-chip memory (like the IMMR area on MPC8xx and
3047 MPC826x processors), on others (parts of) the data cache can be
3048 locked as (mis-) used as memory, etc.
3050 Chris Hallinan posted a good summary of these issues to the
3051 U-Boot mailing list:
3053 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3054 From: "Chris Hallinan" <clh@net1plus.com>
3055 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3058 Correct me if I'm wrong, folks, but the way I understand it
3059 is this: Using DCACHE as initial RAM for Stack, etc, does not
3060 require any physical RAM backing up the cache. The cleverness
3061 is that the cache is being used as a temporary supply of
3062 necessary storage before the SDRAM controller is setup. It's
3063 beyond the scope of this list to explain the details, but you
3064 can see how this works by studying the cache architecture and
3065 operation in the architecture and processor-specific manuals.
3067 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3068 is another option for the system designer to use as an
3069 initial stack/RAM area prior to SDRAM being available. Either
3070 option should work for you. Using CS 4 should be fine if your
3071 board designers haven't used it for something that would
3072 cause you grief during the initial boot! It is frequently not
3075 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
3076 with your processor/board/system design. The default value
3077 you will find in any recent u-boot distribution in
3078 walnut.h should work for you. I'd set it to a value larger
3079 than your SDRAM module. If you have a 64MB SDRAM module, set
3080 it above 400_0000. Just make sure your board has no resources
3081 that are supposed to respond to that address! That code in
3082 start.S has been around a while and should work as is when
3083 you get the config right.
3088 It is essential to remember this, since it has some impact on the C
3089 code for the initialization procedures:
3091 * Initialized global data (data segment) is read-only. Do not attempt
3094 * Do not use any uninitialized global data (or implicitly initialized
3095 as zero data - BSS segment) at all - this is undefined, initiali-
3096 zation is performed later (when relocating to RAM).
3098 * Stack space is very limited. Avoid big data buffers or things like
3101 Having only the stack as writable memory limits means we cannot use
3102 normal global data to share information between the code. But it
3103 turned out that the implementation of U-Boot can be greatly
3104 simplified by making a global data structure (gd_t) available to all
3105 functions. We could pass a pointer to this data as argument to _all_
3106 functions, but this would bloat the code. Instead we use a feature of
3107 the GCC compiler (Global Register Variables) to share the data: we
3108 place a pointer (gd) to the global data into a register which we
3109 reserve for this purpose.
3111 When choosing a register for such a purpose we are restricted by the
3112 relevant (E)ABI specifications for the current architecture, and by
3113 GCC's implementation.
3115 For PowerPC, the following registers have specific use:
3117 R2: reserved for system use
3118 R3-R4: parameter passing and return values
3119 R5-R10: parameter passing
3120 R13: small data area pointer
3124 (U-Boot also uses R12 as internal GOT pointer. r12
3125 is a volatile register so r12 needs to be reset when
3126 going back and forth between asm and C)
3128 ==> U-Boot will use R2 to hold a pointer to the global data
3130 Note: on PPC, we could use a static initializer (since the
3131 address of the global data structure is known at compile time),
3132 but it turned out that reserving a register results in somewhat
3133 smaller code - although the code savings are not that big (on
3134 average for all boards 752 bytes for the whole U-Boot image,
3135 624 text + 127 data).
3137 On ARM, the following registers are used:
3139 R0: function argument word/integer result
3140 R1-R3: function argument word
3141 R9: platform specific
3142 R10: stack limit (used only if stack checking is enabled)
3143 R11: argument (frame) pointer
3144 R12: temporary workspace
3147 R15: program counter
3149 ==> U-Boot will use R9 to hold a pointer to the global data
3151 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
3153 On Nios II, the ABI is documented here:
3154 https://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
3156 ==> U-Boot will use gp to hold a pointer to the global data
3158 Note: on Nios II, we give "-G0" option to gcc and don't use gp
3159 to access small data sections, so gp is free.
3161 On RISC-V, the following registers are used:
3163 x0: hard-wired zero (zero)
3164 x1: return address (ra)
3165 x2: stack pointer (sp)
3166 x3: global pointer (gp)
3167 x4: thread pointer (tp)
3168 x5: link register (t0)
3169 x8: frame pointer (fp)
3170 x10-x11: arguments/return values (a0-1)
3171 x12-x17: arguments (a2-7)
3172 x28-31: temporaries (t3-6)
3173 pc: program counter (pc)
3175 ==> U-Boot will use gp to hold a pointer to the global data
3180 U-Boot runs in system state and uses physical addresses, i.e. the
3181 MMU is not used either for address mapping nor for memory protection.
3183 The available memory is mapped to fixed addresses using the memory
3184 controller. In this process, a contiguous block is formed for each
3185 memory type (Flash, SDRAM, SRAM), even when it consists of several
3186 physical memory banks.
3188 U-Boot is installed in the first 128 kB of the first Flash bank (on
3189 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3190 booting and sizing and initializing DRAM, the code relocates itself
3191 to the upper end of DRAM. Immediately below the U-Boot code some
3192 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
3193 configuration setting]. Below that, a structure with global Board
3194 Info data is placed, followed by the stack (growing downward).
3196 Additionally, some exception handler code is copied to the low 8 kB
3197 of DRAM (0x00000000 ... 0x00001FFF).
3199 So a typical memory configuration with 16 MB of DRAM could look like
3202 0x0000 0000 Exception Vector code
3205 0x0000 2000 Free for Application Use
3211 0x00FB FF20 Monitor Stack (Growing downward)
3212 0x00FB FFAC Board Info Data and permanent copy of global data
3213 0x00FC 0000 Malloc Arena
3216 0x00FE 0000 RAM Copy of Monitor Code
3217 ... eventually: LCD or video framebuffer
3218 ... eventually: pRAM (Protected RAM - unchanged by reset)
3219 0x00FF FFFF [End of RAM]
3222 System Initialization:
3223 ----------------------
3225 In the reset configuration, U-Boot starts at the reset entry point
3226 (on most PowerPC systems at address 0x00000100). Because of the reset
3227 configuration for CS0# this is a mirror of the on board Flash memory.
3228 To be able to re-map memory U-Boot then jumps to its link address.
3229 To be able to implement the initialization code in C, a (small!)
3230 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3231 which provide such a feature like), or in a locked part of the data
3232 cache. After that, U-Boot initializes the CPU core, the caches and
3235 Next, all (potentially) available memory banks are mapped using a
3236 preliminary mapping. For example, we put them on 512 MB boundaries
3237 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3238 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3239 programmed for SDRAM access. Using the temporary configuration, a
3240 simple memory test is run that determines the size of the SDRAM
3243 When there is more than one SDRAM bank, and the banks are of
3244 different size, the largest is mapped first. For equal size, the first
3245 bank (CS2#) is mapped first. The first mapping is always for address
3246 0x00000000, with any additional banks following immediately to create
3247 contiguous memory starting from 0.
3249 Then, the monitor installs itself at the upper end of the SDRAM area
3250 and allocates memory for use by malloc() and for the global Board
3251 Info data; also, the exception vector code is copied to the low RAM
3252 pages, and the final stack is set up.
3254 Only after this relocation will you have a "normal" C environment;
3255 until that you are restricted in several ways, mostly because you are
3256 running from ROM, and because the code will have to be relocated to a
3260 U-Boot Porting Guide:
3261 ----------------------
3263 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3267 int main(int argc, char *argv[])
3269 sighandler_t no_more_time;
3271 signal(SIGALRM, no_more_time);
3272 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
3274 if (available_money > available_manpower) {
3275 Pay consultant to port U-Boot;
3279 Download latest U-Boot source;
3281 Subscribe to u-boot mailing list;
3284 email("Hi, I am new to U-Boot, how do I get started?");
3287 Read the README file in the top level directory;
3288 Read https://www.denx.de/wiki/bin/view/DULG/Manual;
3289 Read applicable doc/README.*;
3290 Read the source, Luke;
3291 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
3294 if (available_money > toLocalCurrency ($2500))
3297 Add a lot of aggravation and time;
3299 if (a similar board exists) { /* hopefully... */
3300 cp -a board/<similar> board/<myboard>
3301 cp include/configs/<similar>.h include/configs/<myboard>.h
3303 Create your own board support subdirectory;
3304 Create your own board include/configs/<myboard>.h file;
3306 Edit new board/<myboard> files
3307 Edit new include/configs/<myboard>.h
3312 Add / modify source code;
3316 email("Hi, I am having problems...");
3318 Send patch file to the U-Boot email list;
3319 if (reasonable critiques)
3320 Incorporate improvements from email list code review;
3322 Defend code as written;
3328 void no_more_time (int sig)
3337 All contributions to U-Boot should conform to the Linux kernel
3338 coding style; see the kernel coding style guide at
3339 https://www.kernel.org/doc/html/latest/process/coding-style.html, and the
3340 script "scripts/Lindent" in your Linux kernel source directory.
3342 Source files originating from a different project (for example the
3343 MTD subsystem) are generally exempt from these guidelines and are not
3344 reformatted to ease subsequent migration to newer versions of those
3347 Please note that U-Boot is implemented in C (and to some small parts in
3348 Assembler); no C++ is used, so please do not use C++ style comments (//)
3351 Please also stick to the following formatting rules:
3352 - remove any trailing white space
3353 - use TAB characters for indentation and vertical alignment, not spaces
3354 - make sure NOT to use DOS '\r\n' line feeds
3355 - do not add more than 2 consecutive empty lines to source files
3356 - do not add trailing empty lines to source files
3358 Submissions which do not conform to the standards may be returned
3359 with a request to reformat the changes.
3365 Since the number of patches for U-Boot is growing, we need to
3366 establish some rules. Submissions which do not conform to these rules
3367 may be rejected, even when they contain important and valuable stuff.
3369 Please see https://www.denx.de/wiki/U-Boot/Patches for details.
3371 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
3372 see https://lists.denx.de/listinfo/u-boot
3374 When you send a patch, please include the following information with
3377 * For bug fixes: a description of the bug and how your patch fixes
3378 this bug. Please try to include a way of demonstrating that the
3379 patch actually fixes something.
3381 * For new features: a description of the feature and your
3384 * For major contributions, add a MAINTAINERS file with your
3385 information and associated file and directory references.
3387 * When you add support for a new board, don't forget to add a
3388 maintainer e-mail address to the boards.cfg file, too.
3390 * If your patch adds new configuration options, don't forget to
3391 document these in the README file.
3393 * The patch itself. If you are using git (which is *strongly*
3394 recommended) you can easily generate the patch using the
3395 "git format-patch". If you then use "git send-email" to send it to
3396 the U-Boot mailing list, you will avoid most of the common problems
3397 with some other mail clients.
3399 If you cannot use git, use "diff -purN OLD NEW". If your version of
3400 diff does not support these options, then get the latest version of
3403 The current directory when running this command shall be the parent
3404 directory of the U-Boot source tree (i. e. please make sure that
3405 your patch includes sufficient directory information for the
3408 We prefer patches as plain text. MIME attachments are discouraged,
3409 and compressed attachments must not be used.
3411 * If one logical set of modifications affects or creates several
3412 files, all these changes shall be submitted in a SINGLE patch file.
3414 * Changesets that contain different, unrelated modifications shall be
3415 submitted as SEPARATE patches, one patch per changeset.
3420 * Before sending the patch, run the buildman script on your patched
3421 source tree and make sure that no errors or warnings are reported
3422 for any of the boards.
3424 * Keep your modifications to the necessary minimum: A patch
3425 containing several unrelated changes or arbitrary reformats will be
3426 returned with a request to re-formatting / split it.
3428 * If you modify existing code, make sure that your new code does not
3429 add to the memory footprint of the code ;-) Small is beautiful!
3430 When adding new features, these should compile conditionally only
3431 (using #ifdef), and the resulting code with the new feature
3432 disabled must not need more memory than the old code without your
3435 * Remember that there is a size limit of 100 kB per message on the
3436 u-boot mailing list. Bigger patches will be moderated. If they are
3437 reasonable and not too big, they will be acknowledged. But patches
3438 bigger than the size limit should be avoided.