README: update ARM register usage

[karo-tx-uboot.git] / README

diff --git a/README b/README
index 391880765a0865f05a71efc6dedf40d99e61d7fe..2fcad7ff856f408cc9e0122b4751cb41fb118794 100644 (file)
--- a/README
+++ b/README
@@ -35,7 +35,7 @@ Makefile have been tested to some extent and can be considered
 "working". In fact, many of them are used in production systems.
 
 In case of problems see the CHANGELOG and CREDITS files to find out
-who contributed the specific port. The MAINTAINERS file lists board
+who contributed the specific port. The boards.cfg file lists board
 maintainers.
 
 Note: There is no CHANGELOG file in the actual U-Boot source tree;
@@ -144,7 +144,6 @@ Directory Hierarchy:
       /arm1136         Files specific to ARM 1136 CPUs
       /ixp             Files specific to Intel XScale IXP CPUs
       /pxa             Files specific to Intel XScale PXA CPUs
-      /s3c44b0         Files specific to Samsung S3C44B0 CPUs
       /sa1100          Files specific to Intel StrongARM SA1100 CPUs
     /lib               Architecture specific library files
   /avr32               Files generic to AVR32 architecture
@@ -1680,6 +1679,10 @@ CBFS (Coreboot Filesystem) support
                to compress the specified memory at its best effort.
 
 - Compression support:
+               CONFIG_GZIP
+
+               Enabled by default to support gzip compressed images.
+
                CONFIG_BZIP2
 
                If this option is set, support for bzip2 compressed
@@ -1713,6 +1716,11 @@ CBFS (Coreboot Filesystem) support
                then calculate the amount of needed dynamic memory (ensuring
                the appropriate CONFIG_SYS_MALLOC_LEN value).
 
+               CONFIG_LZO
+
+               If this option is set, support for LZO compressed images
+               is included.
+
 - MII/PHY support:
                CONFIG_PHY_ADDR
 
@@ -2641,6 +2649,21 @@ CBFS (Coreboot Filesystem) support
                Note: There is also a sha1sum command, which should perhaps
                be deprecated in favour of 'hash sha1'.
 
+- Freescale i.MX specific commands:
+               CONFIG_CMD_HDMIDETECT
+               This enables 'hdmidet' command which returns true if an
+               HDMI monitor is detected.  This command is i.MX 6 specific.
+
+               CONFIG_CMD_BMODE
+               This enables the 'bmode' (bootmode) command for forcing
+               a boot from specific media.
+
+               This is useful for forcing the ROM's usb downloader to
+               activate upon a watchdog reset which is nice when iterating
+               on U-Boot.  Using the reset button or running bmode normal
+               will set it back to normal.  This command currently
+               supports i.MX53 and i.MX6.
+
 - Signing support:
                CONFIG_RSA
 
@@ -3075,6 +3098,14 @@ FIT uImage format:
                Support for NAND boot using simple NAND drivers that
                expose the cmd_ctrl() interface.
 
+               CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
+               Set for the SPL on PPC mpc8xxx targets, support for
+               arch/powerpc/cpu/mpc8xxx/ddr/libddr.o in SPL binary.
+
+               CONFIG_SPL_COMMON_INIT_DDR
+               Set for common ddr init with serial presence detect in
+               SPL binary.
+
                CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
                CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
                CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
@@ -3144,6 +3175,17 @@ FIT uImage format:
                option to re-enable it. This will affect the output of the
                bootm command when booting a FIT image.
 
+- TPL framework
+               CONFIG_TPL
+               Enable building of TPL globally.
+
+               CONFIG_TPL_PAD_TO
+               Image offset to which the TPL should be padded before appending
+               the TPL payload. By default, this is defined as
+                CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
+                CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
+                payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
+
 Modem Support:
 --------------
 
@@ -4181,6 +4223,11 @@ Low Level (hardware related) configuration options:
                that is executed before the actual U-Boot. E.g. when
                compiling a NAND SPL.
 
+- 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.
+
 - CONFIG_SYS_MPC85XX_NO_RESETVEC
                Only for 85xx systems. If this variable is specified, the section
                .resetvec is not kept and the section .bootpg is placed in the
@@ -4627,6 +4674,12 @@ List of environment variables (most likely not complete):
 
   npe_ucode    - set load address for the NPE microcode
 
+  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
+                 is silent.
+
   tftpsrcport  - If this is set, the value is used for TFTP's
                  UDP source port.
 
@@ -5534,15 +5587,17 @@ On ARM, the following registers are used:
 
        R0:     function argument word/integer result
        R1-R3:  function argument word
-       R9:     GOT pointer
-       R10:    stack limit (used only if stack checking if enabled)
+       R9:     platform specific
+       R10:    stack limit (used only if stack checking is enabled)
        R11:    argument (frame) pointer
        R12:    temporary workspace
        R13:    stack pointer
        R14:    link register
        R15:    program counter
 
-    ==> U-Boot will use R8 to hold a pointer to the global data
+    ==> U-Boot will use R9 to hold a pointer to the global data
+
+    Note: on ARM, only R_ARM_RELATIVE relocations are supported.
 
 On Nios II, the ABI is documented here:
        http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
@@ -5779,8 +5834,8 @@ it:
 
 * For major contributions, your entry to the CREDITS file
 
-* When you add support for a new board, don't forget to add this
-  board to the MAINTAINERS file, too.
+* When you add support for a new board, don't forget to add a
+  maintainer e-mail address to the boards.cfg file, too.
 
 * If your patch adds new configuration options, don't forget to
   document these in the README file.