fdt_support: add missing #ifdef after merge

[karo-tx-uboot.git] / README

diff --git a/README b/README
index fefa71c0a6c5f3adf8ed437e6956227a0e502e8b..fc74c913cb4f24aab19ded12138e31e7aee709c7 100644 (file)
--- a/README
+++ b/README
@@ -273,6 +273,75 @@ run some of U-Boot's tests.
 See board/sandbox/README.sandbox for more details.
 
 
 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:
 ----------------------
 
 Configuration Options:
 ----------------------
 


@@ -621,119 +690,20 @@ The following options need to be configured:
                exists, unlike the similar options in the Linux kernel. Do not
                set these options unless they apply!
 
                exists, unlike the similar options in the Linux kernel. Do not
                set these options unless they apply!
 

-- Driver Model
-               Driver model is a new framework for devices in U-Boot
-               introduced in early 2014. U-Boot is being progressively
-               moved over to this. It offers a consistent device structure,
-               supports grouping devices into classes and has built-in
-               handling of platform data and device tree.
-
-               To enable transition to driver model in a relatively
-               painful fashion, each subsystem can be independently
-               switched between the legacy/ad-hoc approach and the new
-               driver model using the options below. Also, many uclass
-               interfaces include compatibility features which may be
-               removed once the conversion of that subsystem is complete.
-               As a result, the API provided by the subsystem may in fact
-               not change with driver model.
-
-               See doc/driver-model/README.txt for more information.
-
-               CONFIG_DM
-
-               Enable driver model. This brings in the core support,
-               including scanning of platform data on start-up. If
-               CONFIG_OF_CONTROL is enabled, the device tree will be
-               scanned also when available.
-
-               CONFIG_CMD_DM
-
-               Enable driver model test commands. These allow you to print
-               out the driver model tree and the uclasses.
-
-               CONFIG_DM_DEMO
-
-               Enable some demo devices and the 'demo' command. These are
-               really only useful for playing around while trying to
-               understand driver model in sandbox.
-
-               CONFIG_SPL_DM
-
-               Enable driver model in SPL. You will need to provide a
-               suitable malloc() implementation. If you are not using the
-               full malloc() enabled by CONFIG_SYS_SPL_MALLOC_START,
-               consider using CONFIG_SYS_MALLOC_SIMPLE. In that case you
-               must provide CONFIG_SYS_MALLOC_F_LEN to set the size.
-               In most cases driver model will only allocate a few uclasses
-               and devices in SPL, so 1KB should be enable. See
-               CONFIG_SYS_MALLOC_F_LEN for more details on how to enable
-               it.
-
-               CONFIG_DM_SERIAL
-
-               Enable driver model for serial. This replaces
-               drivers/serial/serial.c with the serial uclass, which
-               implements serial_putc() etc. The uclass interface is
-               defined in include/serial.h.
-
-               CONFIG_DM_GPIO
-
-               Enable driver model for GPIO access. The standard GPIO
-               interface (gpio_get_value(), etc.) is then implemented by
-               the GPIO uclass. Drivers provide methods to query the
-               particular GPIOs that they provide. The uclass interface
-               is defined in include/asm-generic/gpio.h.
-
-               CONFIG_DM_SPI
-
-               Enable driver model for SPI. The SPI slave interface
-               (spi_setup_slave(), spi_xfer(), etc.) is then implemented by
-               the SPI uclass. Drivers provide methods to access the SPI
-               buses that they control. The uclass interface is defined in
-               include/spi.h. The existing spi_slave structure is attached
-               as 'parent data' to every slave on each bus. Slaves
-               typically use driver-private data instead of extending the
-               spi_slave structure.
-
-               CONFIG_DM_SPI_FLASH
+               NOTE: The following can be machine specific errata. These
+               do have ability to provide rudimentary version and machine
+               specific checks, but expect no product checks.
+               CONFIG_ARM_ERRATA_430973
+               CONFIG_ARM_ERRATA_454179
+               CONFIG_ARM_ERRATA_621766
+               CONFIG_ARM_ERRATA_798870

 
 

-               Enable driver model for SPI flash. This SPI flash interface
-               (spi_flash_probe(), spi_flash_write(), etc.) is then
-               implemented by the SPI flash uclass. There is one standard
-               SPI flash driver which knows how to probe most chips
-               supported by U-Boot. The uclass interface is defined in
-               include/spi_flash.h, but is currently fully compatible
-               with the old interface to avoid confusion and duplication
-               during the transition parent. SPI and SPI flash must be
-               enabled together (it is not possible to use driver model
-               for one and not the other).
-
-               CONFIG_DM_CROS_EC
-
-               Enable driver model for the Chrome OS EC interface. This
-               allows the cros_ec SPI driver to operate with CONFIG_DM_SPI
-               but otherwise makes few changes. Since cros_ec also supports
-               I2C and LPC (which don't support driver model yet), a full
-               conversion is not yet possible.
-
-
-               ** Code size options: The following options are enabled by
-               default except in SPL. Enable them explicitly to get these
-               features in SPL.
-
-               CONFIG_DM_WARN
-
-               Enable the dm_warn() function. This can use up quite a bit
-               of space for its strings.
-
-               CONFIG_DM_STDIO
-
-               Enable registering a serial device with the stdio library.
-
-               CONFIG_DM_DEVICE_REMOVE
-
-               Enable removing of devices.
+- Tegra SoC options:
+               CONFIG_TEGRA_SUPPORT_NON_SECURE

 
 

+               Support executing U-Boot in non-secure (NS) mode. Certain
+               impossible actions will be skipped if the CPU is in NS mode,
+               such as ARM architectural timer initialization.

 
 - Linux Kernel Interface:
                CONFIG_CLOCKS_IN_MHZ
 
 - Linux Kernel Interface:
                CONFIG_CLOCKS_IN_MHZ


@@ -1257,6 +1227,9 @@ The following options need to be configured:
                SoC, then define this variable and provide board
                specific code for the "hw_watchdog_reset" function.
 
                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
 - U-Boot Version:
                CONFIG_VERSION_VARIABLE
                If this variable is defined, an environment variable


@@ -2207,6 +2180,17 @@ CBFS (Coreboot Filesystem) support
                requests. Increasing this will allow U-Boot to accept offers
                from a BOOTP client in networks with unusually high latency.
 
                requests. Increasing this will allow U-Boot to accept offers
                from a BOOTP client in networks with unusually high latency.
 

+- BOOTP Random transaction ID:
+               CONFIG_BOOTP_RANDOM_ID
+
+               The standard algorithm to generate a DHCP/BOOTP transaction ID
+               by using the MAC address and the current time stamp may not
+               quite unlikely produce duplicate transaction IDs from different
+               clients in the same network. This option creates a transaction
+               ID using the rand() function. Provided that the RNG has been
+               seeded well, this should guarantee unique transaction IDs
+               always.
+

 - DHCP Advanced Options:
                You can fine tune the DHCP functionality by defining
                CONFIG_BOOTP_* symbols:
 - DHCP Advanced Options:
                You can fine tune the DHCP functionality by defining
                CONFIG_BOOTP_* symbols:


@@ -3149,8 +3133,18 @@ CBFS (Coreboot Filesystem) support
                Enable the hash verify command (hash -v). This adds to code
                size a little.
 
                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'.
 
                Note: There is also a sha1sum command, which should perhaps
                be deprecated in favour of 'hash sha1'.


@@ -3176,8 +3170,13 @@ CBFS (Coreboot Filesystem) support
                This enables the RSA algorithm used for FIT image verification
                in U-Boot. See doc/uImage.FIT/signature.txt for more information.
 
                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
                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
 
 - bootcount support:
                CONFIG_BOOTCOUNT_LIMIT


@@ -3439,8 +3438,10 @@ FIT uImage format:
 
                CONFIG_FIT_SIGNATURE
                This option enables signature verification of FIT uImages,
 
                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
 
                WARNING: When relying on signed FIT images with required
                signature check the legacy image format is default


@@ -3493,9 +3494,6 @@ FIT uImage format:
                Adds the MTD partitioning infrastructure from the Linux
                kernel. Needed for UBI support.
 
                Adds the MTD partitioning infrastructure from the Linux
                kernel. Needed for UBI support.
 

-               CONFIG_MTD_NAND_VERIFY_WRITE
-               verify if the written data is correct reread.
-

 - UBI support
                CONFIG_CMD_UBI
 
 - UBI support
                CONFIG_CMD_UBI
 


@@ -3620,6 +3618,16 @@ FIT uImage format:
                CONFIG_SPL_STACK
                Adress of the start of the stack SPL will use
 
                CONFIG_SPL_STACK
                Adress of the start of the stack SPL will use
 

+               CONFIG_SPL_PANIC_ON_RAW_IMAGE
+               When defined, SPL will panic() if the image it has
+               loaded does not have a signature.
+               Defining this is useful when code which loads images
+               in SPL cannot guarantee that absolutely all read errors
+               will be caught.
+               An example is the LPC32XX MLC NAND driver, which will
+               consider that a completely unreadable NAND block is bad,
+               and thus should be skipped silently.
+

                CONFIG_SPL_RELOC_STACK
                Adress of the start of the stack SPL will use after
                relocation.  If unspecified, this is equal to
                CONFIG_SPL_RELOC_STACK
                Adress of the start of the stack SPL will use after
                relocation.  If unspecified, this is equal to


@@ -4200,9 +4208,9 @@ Configuration Settings:
        to this new framework over time. Defining this will disable the
        arch/foo/lib/board.c file and use common/board_f.c and
        common/board_r.c instead. To use this option your architecture
        to this new framework over time. Defining this will disable the
        arch/foo/lib/board.c file and use common/board_f.c and
        common/board_r.c instead. To use this option your architecture

-       must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
-       its config.mk file). If you find problems enabling this option on
-       your board please report the problem and send patches!
+       must support it (i.e. must select HAVE_GENERIC_BOARD in arch/Kconfig).
+       If you find problems enabling this option on your board please report
+       the problem and send patches!

 
 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
        This is set by OMAP boards for the max time that reset should
 
 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
        This is set by OMAP boards for the max time that reset should


@@ -4333,6 +4341,9 @@ to save the current settings.
          If defined, specified the chip address of the EEPROM device.
          The default address is zero.
 
          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
        - 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


@@ -4908,6 +4919,9 @@ Low Level (hardware related) configuration options:
 - CONFIG_FSL_DDR_INTERACTIVE
                Enable interactive DDR debugging. See doc/README.fsl-ddr.
 
 - 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.
 - 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.


@@ -5899,9 +5913,10 @@ option performs the converse operation of the mkimage's second form (the "-d"
 option). Given an image built by mkimage, the dumpimage extracts a "data file"
 from the image:
 
 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:
 
 
 Installing a Linux Image: