X-Git-Url: https://git.librecmc.org/?p=oweals%2Fu-boot.git;a=blobdiff_plain;f=README;h=bcf19836311143bc93f18af744beaac0e29c4651;hp=b493ffeb2d9dc143ab5f90c8ab10b1fa8d0d6f18;hb=1099b2abef35c3c887f6afac1a8ef18c7924d5d2;hpb=7127151d538d878bd073ca6d6cca630a4b35b76f diff --git a/README b/README index b493ffeb2d..bcf1983631 100644 --- a/README +++ b/README @@ -83,7 +83,7 @@ Where we come from: * Provide extended interface to Linux boot loader * S-Record download * network boot - * PCMCIA / CompactFlash / ATA disk / SCSI ... boot + * ATA disk / SCSI ... boot - create ARMBoot project (http://sourceforge.net/projects/armboot) - add other CPU families (starting with ARM) - create U-Boot project (http://sourceforge.net/projects/u-boot) @@ -267,6 +267,13 @@ board_init_f(): - 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 + - for specific scenarios on certain architectures an early BSS *can* + be made available (via CONFIG_SPL_EARLY_BSS by moving the clearing + of BSS prior to entering board_init_f()) but doing so is discouraged. + Instead it is strongly recommended to architect any code changes + or additions such to not depend on the availability of BSS during + board_init_f() as indicated in other sections of this README to + maintain compatibility and consistency across the entire code base. - must return normally from this function (don't call board_init_r() directly) @@ -889,8 +896,6 @@ The following options need to be configured: CONFIG_TULIP Support for Digital 2114x chips. - Optional CONFIG_TULIP_SELECT_MEDIA for board specific - modem chip initialisation (KS8761/QS6611). CONFIG_NATSEMI Support for National dp83815 chips. @@ -1325,21 +1330,6 @@ The following options need to be configured: can be displayed via the splashscreen support or the bmp command. -- Compression support: - CONFIG_GZIP - - Enabled by default to support gzip compressed images. - - CONFIG_BZIP2 - - If this option is set, support for bzip2 compressed - images is included. If not, only uncompressed and gzip - compressed images are supported. - - NOTE: the bzip2 algorithm requires a lot of RAM, so - the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should - be at least 4MB. - - MII/PHY support: CONFIG_PHY_CLOCK_FREQ (ppc4xx) @@ -1562,14 +1552,6 @@ The following options need to be configured: This enable the NEW i2c subsystem, and will allow you to use i2c commands at the u-boot command line (as long as you set - CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c - based realtime clock chips or other i2c devices. See - common/cmd_i2c.c for a description of the command line - interface. - - ported i2c driver to the new framework: - - drivers/i2c/soft_i2c.c: - - activate first bus with CONFIG_SYS_I2C_SOFT define CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE for defining speed and slave address - activate second bus with I2C_SOFT_DECLARATIONS2 define @@ -1625,16 +1607,6 @@ The following options need to be configured: - activate this driver with CONFIG_SYS_I2C_RCAR - This driver adds 4 i2c buses - - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0 - - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0 - - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1 - - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1 - - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2 - - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2 - - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3 - - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3 - - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses - - drivers/i2c/sh_i2c.c: - activate this driver with CONFIG_SYS_I2C_SH - This driver adds from 2 to 5 i2c buses @@ -2453,7 +2425,7 @@ typically in board_init_f() and board_init_r(). Configuration Settings: ----------------------- -- CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit. +- MEM_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit. Optionally it can be defined to support 64-bit memory commands. - CONFIG_SYS_LONGHELP: Defined when you want long help messages included; @@ -2478,14 +2450,6 @@ Configuration Settings: - CONFIG_SYS_BAUDRATE_TABLE: List of legal baudrate settings for this board. -- CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END: - Begin and End addresses of the area used by the - simple memory test. - -- CONFIG_SYS_MEMTEST_SCRATCH: - Scratch address used by the alternate memory test - You only need to set this if address zero isn't writeable - - CONFIG_SYS_MEM_RESERVE_SECURE Only implemented for ARMv8 for now. If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory @@ -2742,10 +2706,6 @@ Configuration Settings: regular expression. This allows multiple variables to define the same flags without explicitly listing them for each variable. -- CONFIG_ENV_ACCESS_IGNORE_FORCE - If defined, don't allow the -f switch to env set override variable - access flags. - The following definitions that deal with the placement and management of environment data (variable area); in general, we support the following configurations: @@ -2863,32 +2823,6 @@ Low Level (hardware related) configuration options: If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be forced to a value that ensures that CCSR is not relocated. -- Floppy Disk Support: - CONFIG_SYS_FDC_DRIVE_NUMBER - - the default drive number (default value 0) - - CONFIG_SYS_ISA_IO_STRIDE - - defines the spacing between FDC chipset registers - (default value 1) - - CONFIG_SYS_ISA_IO_OFFSET - - defines the offset of register from address. It - depends on which part of the data bus is connected to - the FDC chipset. (default value 0) - - If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and - CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their - default value. - - 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-dependent - initializations. - - CONFIG_IDE_AHB: Most IDE controllers were designed to be connected with PCI interface. Only few of them were designed for AHB interface. @@ -2976,7 +2910,7 @@ Low Level (hardware related) configuration options: - CONFIG_SYS_SRIOn_MEM_VIRT: Virtual Address of SRIO port 'n' memory region -- CONFIG_SYS_SRIOn_MEM_PHYS: +- CONFIG_SYS_SRIOn_MEM_PHYxS: Physical Address of SRIO port 'n' memory region - CONFIG_SYS_SRIOn_MEM_SIZE: @@ -3044,7 +2978,7 @@ Low Level (hardware related) configuration options: Add the "loopw" memory command. This only takes effect if the memory commands are activated globally (CONFIG_CMD_MEMORY). -- CONFIG_MX_CYCLIC +- CONFIG_CMD_MX_CYCLIC Add the "mdc" and "mwc" memory commands. These are cyclic "md/mw" commands. Examples: @@ -3075,14 +3009,16 @@ Low Level (hardware related) configuration options: instruction cache) is still performed. - CONFIG_SPL_BUILD - Modifies the behaviour of start.S when compiling a loader - that is executed before the actual U-Boot. E.g. when - compiling a NAND SPL. + Set when the currently-running compilation is for an artifact + that will end up in the SPL (as opposed to the TPL or U-Boot + proper). Code that needs stage-specific behavior should check + this. - CONFIG_TPL_BUILD - Modifies the behaviour of start.S when compiling a loader - that is executed after the SPL and before the actual U-Boot. - It is loaded by the SPL. + Set when the currently-running compilation is for an artifact + that will end up in the TPL (as opposed to the SPL or U-Boot + proper). Code that needs stage-specific behavior should check + this. - CONFIG_SYS_MPC85XX_NO_RESETVEC Only for 85xx systems. If this variable is specified, the section @@ -3203,16 +3139,6 @@ necessary. For example using the ELDK on a 4xx CPU, please enter: $ CROSS_COMPILE=ppc_4xx- $ export CROSS_COMPILE -Note: If you wish to generate Windows versions of the utilities in - the tools directory you can use the MinGW toolchain - (http://www.mingw.org). Set your HOST tools to the MinGW - toolchain and execute 'make tools'. For example: - - $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools - - Binaries such as tools/mkimage.exe will be created which can - be executed on computers running Windows. - U-Boot is intended to be simple to build. After installing the sources you must configure U-Boot for one specific board type. This is done by typing: @@ -3220,9 +3146,9 @@ is done by typing: make NAME_defconfig where "NAME_defconfig" is the name of one of the existing configu- -rations; see boards.cfg for supported names. +rations; see configs/*_defconfig for supported names. -Note: for some board special configuration names may exist; check if +Note: for some boards special configuration names may exist; check if additional information is available from the board vendor; for instance, the TQM823L systems are available without (standard) or with LCD support. You can select such additional "features" @@ -3299,7 +3225,7 @@ Testing of U-Boot Modifications, Ports to New Hardware, etc.: If you have modified U-Boot sources (for instance added a new board or support for new devices, a new CPU, etc.) you are expected to provide feedback to the other developers. The feedback normally takes -the form of a "patch", i. e. a context diff against a certain (latest +the form of a "patch", i.e. a context diff against a certain (latest official or latest in the git repository) version of U-Boot sources. But before you submit such a patch, please verify that your modifi- @@ -4656,7 +4582,7 @@ int main(int argc, char *argv[]) while (learning) { Read the README file in the top level directory; Read http://www.denx.de/twiki/bin/view/DULG/Manual; - Read applicable doc/*.README; + Read applicable doc/README.*; Read the source, Luke; /* find . -name "*.[chS]" | xargs grep -i */ } @@ -4751,8 +4677,6 @@ it: * For new features: a description of the feature and your implementation. -* A CHANGELOG entry as plaintext (separate from the patch) - * For major contributions, add a MAINTAINERS file with your information and associated file and directory references.