README: update MIPS related informations

Amend section 'Directory Hierarchy' for current MIPS directory.
Describe config options for MIPS.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@googlemail.com>
Acked-by: Thomas Langer <thomas.langer@lantiq.com>
Signed-off-by: Shinya Kuribayashi <skuribay@pobox.com>

diff --git a/README b/README
index aec28e3..a325892 100644 (file)
--- a/README
+++ b/README
@@ -180,6 +180,7 @@ Directory Hierarchy:
     /lib               Architecture specific library files
   /mips                        Files generic to MIPS architecture
     /cpu               CPU specific files
+      /mips32          Files specific to MIPS32 CPUs
     /lib               Architecture specific library files
   /nios2               Files generic to Altera NIOS2 architecture
     /cpu               CPU specific files
@@ -382,6 +383,38 @@ The following options need to be configured:
                2. The core frequency as calculated above is multiplied
                by this value.
 
+- MIPS CPU options:
+               CONFIG_SYS_INIT_SP_OFFSET
+
+               Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
+               pointer. This is needed for the temporary stack before
+               relocation.
+
+               CONFIG_SYS_MIPS_CACHE_MODE
+
+               Cache operation mode for the MIPS CPU.
+               See also arch/mips/include/asm/mipsregs.h.
+               Possible values are:
+                       CONF_CM_CACHABLE_NO_WA
+                       CONF_CM_CACHABLE_WA
+                       CONF_CM_UNCACHED
+                       CONF_CM_CACHABLE_NONCOHERENT
+                       CONF_CM_CACHABLE_CE
+                       CONF_CM_CACHABLE_COW
+                       CONF_CM_CACHABLE_CUW
+                       CONF_CM_CACHABLE_ACCELERATED
+
+               CONFIG_SYS_XWAY_EBU_BOOTCFG
+
+               Special option for Lantiq XWAY SoCs for booting from NOR flash.
+               See also arch/mips/cpu/mips32/start.S.
+
+               CONFIG_XWAY_SWAP_BYTES
+
+               Enable compilation of tools/xway-swap-bytes needed for Lantiq
+               XWAY SoCs for booting from NOR flash. The U-Boot image needs to
+               be swapped if a flash programmer is used.
+
 - Linux Kernel Interface:
                CONFIG_CLOCKS_IN_MHZ
 
@@ -3070,7 +3103,7 @@ Low Level (hardware related) configuration options:
                globally (CONFIG_CMD_MEM).
 
 - CONFIG_SKIP_LOWLEVEL_INIT
-               [ARM only] If this variable is defined, then certain
+               [ARM, MIPS only] If this variable is defined, then certain
                low level initializations (like setting up the memory
                controller) are omitted and/or U-Boot does not
                relocate itself into RAM.