X-Git-Url: https://git.kernelconcepts.de/?a=blobdiff_plain;f=README;h=28c0bf40845ca08372f96d011eefbde22bfe4459;hb=f8fc4cc60d6da22622e3b86a34241bf8175c45ea;hp=a435c8b2fa7ce054530002b7d5d8f20f197710ad;hpb=3d5920a31bb846249385e1ca5c086662c39bc44e;p=karo-tx-uboot.git diff --git a/README b/README index a435c8b2fa..28c0bf4084 100644 --- a/README +++ b/README @@ -273,6 +273,75 @@ run some of U-Boot's tests. 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: ---------------------- @@ -621,6 +690,18 @@ The following options need to be configured: exists, unlike the similar options in the Linux kernel. Do not set these options unless they apply! + 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_798870 + +- 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. + - Driver Model Driver model is a new framework for devices in U-Boot introduced in early 2014. U-Boot is being progressively @@ -734,7 +815,6 @@ The following options need to be configured: Enable removing of devices. - - Linux Kernel Interface: CONFIG_CLOCKS_IN_MHZ @@ -1257,6 +1337,9 @@ The following options need to be configured: 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 @@ -1974,6 +2057,26 @@ CBFS (Coreboot Filesystem) support the console jump but can help speed up operation when scrolling is slow. + CONFIG_LCD_ROTATION + + Sometimes, for example if the display is mounted in portrait + mode or even if it's mounted landscape but rotated by 180degree, + we need to rotate our content of the display relative to the + framebuffer, so that user can read the messages which are + printed out. + Once CONFIG_LCD_ROTATION is defined, the lcd_console will be + initialized with a given rotation from "vl_rot" out of + "vidinfo_t" which is provided by the board specific code. + The value for vl_rot is coded as following (matching to + fbcon=rotate: linux-kernel commandline): + 0 = no rotation respectively 0 degree + 1 = 90 degree rotation + 2 = 180 degree rotation + 3 = 270 degree rotation + + If CONFIG_LCD_ROTATION is not defined, the console will be + initialized with 0degree rotation. + CONFIG_LCD_BMP_RLE8 Support drawing of RLE8-compressed bitmaps on the LCD. @@ -3160,8 +3263,18 @@ CBFS (Coreboot Filesystem) support 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'. @@ -3226,55 +3339,6 @@ CBFS (Coreboot Filesystem) support example, some LED's) on your board. At the moment, the following checkpoints are implemented: -- Detailed boot stage timing - CONFIG_BOOTSTAGE - Define this option to get detailed timing of each stage - of the boot process. - - CONFIG_BOOTSTAGE_USER_COUNT - This is the number of available user bootstage records. - Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...) - a new ID will be allocated from this stash. If you exceed - the limit, recording will stop. - - CONFIG_BOOTSTAGE_REPORT - Define this to print a report before boot, similar to this: - - Timer summary in microseconds: - Mark Elapsed Stage - 0 0 reset - 3,575,678 3,575,678 board_init_f start - 3,575,695 17 arch_cpu_init A9 - 3,575,777 82 arch_cpu_init done - 3,659,598 83,821 board_init_r start - 3,910,375 250,777 main_loop - 29,916,167 26,005,792 bootm_start - 30,361,327 445,160 start_kernel - - CONFIG_CMD_BOOTSTAGE - Add a 'bootstage' command which supports printing a report - and un/stashing of bootstage data. - - CONFIG_BOOTSTAGE_FDT - Stash the bootstage information in the FDT. A root 'bootstage' - node is created with each bootstage id as a child. Each child - has a 'name' property and either 'mark' containing the - mark time in microsecond, or 'accum' containing the - accumulated time for that bootstage id in microseconds. - For example: - - bootstage { - 154 { - name = "board_init_f"; - mark = <3575678>; - }; - 170 { - name = "lcd"; - accum = <33482>; - }; - }; - - Code in the Linux kernel can find this in /proc/devicetree. Legacy uImage format: @@ -3368,9 +3432,9 @@ Legacy uImage format: 65 net/eth.c Ethernet found. -80 common/cmd_net.c usage wrong - 80 common/cmd_net.c before calling NetLoop() - -81 common/cmd_net.c some error in NetLoop() occurred - 81 common/cmd_net.c NetLoop() back without error + 80 common/cmd_net.c before calling net_loop() + -81 common/cmd_net.c some error in net_loop() occurred + 81 common/cmd_net.c net_loop() back without error -82 common/cmd_net.c size == 0 (File with size 0 loaded) 82 common/cmd_net.c trying automatic boot 83 common/cmd_net.c running "source" command @@ -3455,8 +3519,10 @@ FIT uImage format: 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 @@ -3509,9 +3575,6 @@ FIT uImage format: 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 @@ -3636,6 +3699,16 @@ FIT uImage format: 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 @@ -4216,9 +4289,9 @@ 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 - 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 @@ -4349,6 +4422,9 @@ to save the current settings. 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 @@ -4924,6 +5000,9 @@ Low Level (hardware related) configuration options: - 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.