/lib Architecture specific library files
/powerpc Files generic to PowerPC architecture
/cpu CPU specific files
- /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
/mpc5xx Files specific to Freescale MPC5xx CPUs
/mpc5xxx Files specific to Freescale MPC5xxx CPUs
/mpc8xx Files specific to Freescale MPC8xx CPUs
- /mpc824x Files specific to Freescale MPC824x CPUs
/mpc8260 Files specific to Freescale MPC8260 CPUs
/mpc85xx Files specific to Freescale MPC85xx CPUs
/ppc4xx Files specific to AMCC PowerPC 4xx CPUs
See board/sandbox/README.sandbox for more details.
+Board Initialisation Flow:
+--------------------------
+
+This is the intended start-up flow for boards. This should apply for both
+SPL and U-Boot proper (i.e. they both follow the same rules). At present SPL
+mostly uses a separate code path, but the funtion names and roles of each
+function are the same. Some boards or architectures may not conform to this.
+At least most ARM boards which use CONFIG_SPL_FRAMEWORK conform to this.
+
+Execution starts with start.S with three functions called during init after
+that. The purpose and limitations of each is described below.
+
+lowlevel_init():
+ - purpose: essential init to permit execution to reach board_init_f()
+ - no global_data or BSS
+ - there is no stack (ARMv7 may have one but it will soon be removed)
+ - must not set up SDRAM or use console
+ - must only do the bare minimum to allow execution to continue to
+ board_init_f()
+ - this is almost never needed
+ - return normally from this function
+
+board_init_f():
+ - purpose: set up the machine ready for running board_init_r():
+ i.e. SDRAM and serial UART
+ - global_data is available
+ - stack is in SRAM
+ - BSS is not available, so you cannot use global/static variables,
+ only stack variables and global_data
+
+ Non-SPL-specific notes:
+ - dram_init() is called to set up DRAM. If already done in SPL this
+ can do nothing
+
+ SPL-specific notes:
+ - you can override the entire board_init_f() function with your own
+ version as needed.
+ - preloader_console_init() can be called here in extremis
+ - should set up SDRAM, and anything needed to make the UART work
+ - these is no need to clear BSS, it will be done by crt0.S
+ - must return normally from this function (don't call board_init_r()
+ directly)
+
+Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
+this point the stack and global_data are relocated to below
+CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
+memory.
+
+board_init_r():
+ - purpose: main execution, common code
+ - global_data is available
+ - SDRAM is available
+ - BSS is available, all static/global variables can be used
+ - execution eventually continues to main_loop()
+
+ Non-SPL-specific notes:
+ - U-Boot is relocated to the top of memory and is now running from
+ there.
+
+ SPL-specific notes:
+ - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
+ CONFIG_SPL_STACK_R_ADDR points into SDRAM
+ - preloader_console_init() can be called here - typically this is
+ done by defining CONFIG_SPL_BOARD_INIT and then supplying a
+ spl_board_init() function containing this call
+ - loads U-Boot or (in falcon mode) Linux
+
+
+
Configuration Options:
----------------------
multiple fs option at one time
for marvell soc family
-- MPC824X Family Member (if CONFIG_MPC824X is defined)
- Define exactly one of
- CONFIG_MPC8240, CONFIG_MPC8245
-
- 8xx CPU Options: (if using an MPC8xx CPU)
CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
get_gclk_freq() cannot work
CONFIG_A003399_NOR_WORKAROUND
Enables a workaround for IFC erratum A003399. It is only
- requred during NOR boot.
+ required during NOR boot.
CONFIG_A008044_WORKAROUND
Enables a workaround for T1040/T1042 erratum A008044. It is only
- requred during NAND boot and valid for Rev 1.0 SoC revision
+ required during NAND boot and valid for Rev 1.0 SoC revision
CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
time of U-boot entry and is required to be re-initialized.
CONFIG_DEEP_SLEEP
- Inidcates this SoC supports deep sleep feature. If deep sleep is
+ Indicates this SoC supports deep sleep feature. If deep sleep is
supported, core will start to execute uboot when wakes up.
- Generic CPU options:
CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
- When transferring memsize parameter to linux, some versions
+ When transferring memsize parameter to Linux, some versions
expect it to be in bytes, others in MB.
Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
SoC, then define this variable and provide board
specific code for the "hw_watchdog_reset" function.
+ CONFIG_AT91_HW_WDT_TIMEOUT
+ specify the timeout in seconds. default 2 seconds.
+
- U-Boot Version:
CONFIG_VERSION_VARIABLE
If this variable is defined, an environment variable
CONFIG_LCD_ALIGNMENT
- Normally the LCD is page-aligned (tyically 4KB). If this is
+ Normally the LCD is page-aligned (typically 4KB). If this is
defined then the LCD will be aligned to this value instead.
For ARM it is sometimes useful to use MMU_SECTION_SIZE
here, since it is cheaper to change data cache settings on
can be displayed via the splashscreen support or the
bmp command.
-- Do compresssing for memory range:
+- Do compressing for memory range:
CONFIG_CMD_ZIP
If this option is set, it would use zlib deflate method
- define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
- define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
- define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
- If thoses defines are not set, default value is 100000
+ If those defines are not set, default value is 100000
for speed, and 0 for slave.
- drivers/i2c/rcar_i2c.c:
- CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
- CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
- CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
- - CONFIF_SYS_I2C_SH_NUM_CONTROLLERS for nummber of i2c buses
+ - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
- drivers/i2c/omap24xx_i2c.c
- activate this driver with CONFIG_SYS_I2C_OMAP24XX
additional defines:
CONFIG_SYS_NUM_I2C_BUSES
- Hold the number of i2c busses you want to use. If you
+ Hold the number of i2c buses you want to use. If you
don't use/have i2c muxes on your i2c bus, this
is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
omit this define.
define.
CONFIG_SYS_I2C_BUSES
- hold a list of busses you want to use, only used if
+ hold a list of buses you want to use, only used if
CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
CONFIG_SYS_NUM_I2C_BUSES = 9:
CONFIG_SYS_FPGA_WAIT_INIT
- Maximum time to wait for the INIT_B line to deassert
- after PROB_B has been deasserted during a Virtex II
+ Maximum time to wait for the INIT_B line to de-assert
+ after PROB_B has been de-asserted during a Virtex II
FPGA configuration sequence. The default time is 500
ms.
CONFIG_SYS_FPGA_WAIT_BUSY
- Maximum time to wait for BUSY to deassert during
+ Maximum time to wait for BUSY to de-assert during
Virtex II FPGA configuration. The default is 5 ms.
CONFIG_SYS_FPGA_WAIT_CONFIG
of the backslashes before semicolons and special
symbols.
-- Commandline Editing and History:
+- Command Line Editing and History:
CONFIG_CMDLINE_EDITING
Enable editing and History functions for interactive
- commandline input operations
+ command line input operations
- Default Environment:
CONFIG_EXTRA_ENV_SETTINGS
CONFIG_DELAY_ENVIRONMENT
Normally the environment is loaded when the board is
- intialised so that it is available to U-Boot. This inhibits
+ initialised so that it is available to U-Boot. This inhibits
that so that the environment is not available until
explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
this is instead controlled by the value of
Define this option to use dual flash support where two flash
memories can be connected with a given cs line.
- currently Xilinx Zynq qspi support these type of connections.
+ Currently Xilinx Zynq qspi supports these type of connections.
CONFIG_SYS_SPI_ST_ENABLE_WP_PIN
enable the W#/Vpp signal to disable writing to the status
Enable the hash verify command (hash -v). This adds to code
size a little.
- CONFIG_SHA1 - support SHA1 hashing
- CONFIG_SHA256 - support SHA256 hashing
+ CONFIG_SHA1 - This option enables support of hashing using SHA1
+ algorithm. The hash is calculated in software.
+ CONFIG_SHA256 - This option enables support of hashing using
+ SHA256 algorithm. The hash is calculated in software.
+ CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
+ for SHA1/SHA256 hashing.
+ This affects the 'hash' command and also the
+ hash_lookup_algo() function.
+ CONFIG_SHA_PROG_HW_ACCEL - This option enables
+ hardware-acceleration for SHA1/SHA256 progressive hashing.
+ Data can be streamed in a block at a time and the hashing
+ is performed in hardware.
Note: There is also a sha1sum command, which should perhaps
be deprecated in favour of 'hash sha1'.
This enables the RSA algorithm used for FIT image verification
in U-Boot. See doc/uImage.FIT/signature.txt for more information.
+ The Modular Exponentiation algorithm in RSA is implemented using
+ driver model. So CONFIG_DM needs to be enabled by default for this
+ library to function.
+
The signing part is build into mkimage regardless of this
- option.
+ option. The software based modular exponentiation is built into
+ mkimage irrespective of this option.
- bootcount support:
CONFIG_BOOTCOUNT_LIMIT
CONFIG_FIT_SIGNATURE
This option enables signature verification of FIT uImages,
- using a hash signed and verified using RSA. See
- doc/uImage.FIT/signature.txt for more details.
+ using a hash signed and verified using RSA. If
+ CONFIG_SHA_PROG_HW_ACCEL is defined, i.e support for progressive
+ hashing is available using hardware, RSA library will use it.
+ See doc/uImage.FIT/signature.txt for more details.
WARNING: When relying on signed FIT images with required
signature check the legacy image format is default
CONFIG_SYS_NAND_HW_ECC_OOBFIRST
Define this if you need to first read the OOB and then the
- data. This is used for example on davinci plattforms.
+ data. This is used, for example, on davinci platforms.
CONFIG_SPL_OMAP3_ID_NAND
Support for an OMAP3-specific set of functions to return the
This feature allocates regions with increasing addresses
within the region. calloc() is supported, but realloc()
is not available. free() is supported but does nothing.
- The memory will be freed (or in fact just forgotton) when
+ The memory will be freed (or in fact just forgotten) when
U-Boot relocates itself.
Pre-relocation malloc() is only supported on ARM and sandbox
boards which do not use the full malloc in SPL (which is
enabled with CONFIG_SYS_SPL_MALLOC_START).
+- CONFIG_SYS_NONCACHED_MEMORY:
+ Size of non-cached memory area. This area of memory will be
+ typically located right below the malloc() area and mapped
+ uncached in the MMU. This is useful for drivers that would
+ otherwise require a lot of explicit cache maintenance. For
+ some drivers it's also impossible to properly maintain the
+ cache. For example if the regions that need to be flushed
+ are not a multiple of the cache-line size, *and* padding
+ cannot be allocated between the regions to align them (i.e.
+ if the HW requires a contiguous array of regions, and the
+ size of each region is not cache-aligned), then a flush of
+ one region may result in overwriting data that hardware has
+ written to another region in the same cache-line. This can
+ happen for example in network drivers where descriptors for
+ buffers are typically smaller than the CPU cache-line (e.g.
+ 16 bytes vs. 32 or 64 bytes).
+
+ Non-cached memory is only supported on 32-bit ARM at present.
+
- CONFIG_SYS_BOOTM_LEN:
Normally compressed uImages are limited to an
uncompressed size of 8 MBytes. If this is not enough,
The format of the list is:
type_attribute = [s|d|x|b|i|m]
- access_atribute = [a|r|o|c]
- attributes = type_attribute[access_atribute]
+ access_attribute = [a|r|o|c]
+ attributes = type_attribute[access_attribute]
entry = variable_name[:attributes]
list = entry[,list]
- CONFIG_ENV_FLAGS_LIST_DEFAULT
Define this to a list (string) to define the ".flags"
- envirnoment variable in the default or embedded environment.
+ environment variable in the default or embedded environment.
- CONFIG_ENV_FLAGS_LIST_STATIC
Define this to a list (string) to define validation that
- CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
This is set by OMAP boards for the max time that reset should
be asserted. See doc/README.omap-reset-time for details on how
- the value can be calulated on a given board.
+ the value can be calculated on a given board.
- CONFIG_USE_STDINT
If stdint.h is available with your toolchain you can define this
provision.
BE CAREFUL! The first access to the environment happens quite early
-in U-Boot initalization (when we try to get the setting of for the
+in U-Boot initialization (when we try to get the setting of for the
console baudrate). You *MUST* have mapped your NVRAM area then, or
U-Boot will hang.
If defined, specified the chip address of the EEPROM device.
The default address is zero.
+ - CONFIG_SYS_I2C_EEPROM_BUS:
+ If defined, specified the i2c bus of the EEPROM device.
+
- CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
If defined, the number of bits used to address bytes in a
single page in the EEPROM device. A 64 byte page, for example
table, or the whole device D if has no partition
table.
- "D:auto": first partition in device D with bootable flag set.
- If none, first valid paratition in device D. If no
+ If none, first valid partition in device D. If no
partition table then means device D.
- FAT_ENV_FILE:
It's a string of the FAT file name. This file use to store the
- envrionment.
+ environment.
- CONFIG_FAT_WRITE:
- This should be defined. Otherwise it cannot save the envrionment file.
+ This should be defined. Otherwise it cannot save the environment file.
- CONFIG_ENV_IS_IN_MMC:
if CONFIG_SYS_FDC_HW_INIT is defined, then the function
fdc_hw_init() is called at the beginning of the FDC
setup. fdc_hw_init() must be provided by the board
- source code. It is used to make hardware dependant
+ source code. It is used to make hardware-dependent
initializations.
- CONFIG_IDE_AHB:
When software is doing ATA command and data transfer to
IDE devices through IDE-AHB controller, some additional
registers accessing to these kind of IDE-AHB controller
- is requierd.
+ is required.
- CONFIG_SYS_IMMR: Physical address of the Internal Memory.
DO NOT CHANGE unless you know exactly what you're
required.
- CONFIG_PCI_ENUM_ONLY
- Only scan through and get the devices on the busses.
+ Only scan through and get the devices on the buses.
Don't do any setup work, presumably because someone or
something has already done it, and we don't need to do it
a second time. Useful for platforms that are pre-booted
- CONFIG_FSL_DDR_INTERACTIVE
Enable interactive DDR debugging. See doc/README.fsl-ddr.
+- CONFIG_FSL_DDR_SYNC_REFRESH
+ Enable sync of refresh for multiple controllers.
+
- CONFIG_SYS_83XX_DDR_USES_CS0
Only for 83xx systems. If specified, then DDR should
be configured using CS0 and CS1 instead of CS2 and CS3.
npe_ucode - set load address for the NPE microcode
- silent_linux - If set then linux will be told to boot silently, by
+ silent_linux - If set then Linux will be told to boot silently, by
changing the console to be empty. If "yes" it will be
made silent. If "no" it will not be made silent. If
unset, then it will be made silent if the U-Boot console
---------------------------------------------
For some environment variables, the behavior of u-boot needs to change
-when their values are changed. This functionailty allows functions to
+when their values are changed. This functionality allows functions to
be associated with arbitrary variables. On creation, overwrite, or
deletion, the callback will provide the opportunity for some side
effect to happen or for the change to be rejected.
with the same list format above. Any association in ".callbacks" will
override any association in the static list. You can define
CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
-".callbacks" envirnoment variable in the default or embedded environment.
+".callbacks" environment variable in the default or embedded environment.
Command Line Parsing:
option). Given an image built by mkimage, the dumpimage extracts a "data file"
from the image:
- tools/dumpimage -i image -p position data_file
- -i ==> extract from the 'image' a specific 'data_file', \
- indexed by 'position'
+ tools/dumpimage -i image -T type -p position data_file
+ -i ==> extract from the 'image' a specific 'data_file'
+ -T ==> set image type to 'type'
+ -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
Installing a Linux Image:
* Initialized global data (data segment) is read-only. Do not attempt
to write it.
-* Do not use any uninitialized global data (or implicitely initialized
+* Do not use any uninitialized global data (or implicitly initialized
as zero data - BSS segment) at all - this is undefined, initiali-
zation is performed later (when relocating to RAM).
that.
Having only the stack as writable memory limits means we cannot use
-normal global data to share information beween the code. But it
+normal global data to share information between the code. But it
turned out that the implementation of U-Boot can be greatly
simplified by making a global data structure (gd_t) available to all
functions. We could pass a pointer to this data as argument to _all_
In the reset configuration, U-Boot starts at the reset entry point
(on most PowerPC systems at address 0x00000100). Because of the reset
-configuration for CS0# this is a mirror of the onboard Flash memory.
+configuration for CS0# this is a mirror of the on board Flash memory.
To be able to re-map memory U-Boot then jumps to its link address.
To be able to implement the initialization code in C, a (small!)
initial stack is set up in the internal Dual Ported RAM (in case CPUs
Source files originating from a different project (for example the
MTD subsystem) are generally exempt from these guidelines and are not
-reformated to ease subsequent migration to newer versions of those
+reformatted to ease subsequent migration to newer versions of those
sources.
Please note that U-Boot is implemented in C (and to some small parts in