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/*
* arch/cris/boot/compressed/head.S
*
* Copyright (C) 1999, 2001 Axis Communications AB
*
* Code that sets up the DRAM registers, calls the
* decompressor to unpack the piggybacked kernel, and jumps.
*
*/
#define ASSEMBLER_MACROS_ONLY
#include <arch/sv_addr_ag.h>
#define RAM_INIT_MAGIC 0x56902387
#define COMMAND_LINE_MAGIC 0x87109563
;; Exported symbols
.globl input_data
.text
nop
di
;; We need to initialze DRAM registers before we start using the DRAM
cmp.d RAM_INIT_MAGIC, $r8 ; Already initialized?
beq dram_init_finished
nop
#include "../../lib/dram_init.S"
dram_init_finished:
;; Initiate the PA and PB ports
move.b CONFIG_ETRAX_DEF_R_PORT_PA_DATA, $r0
move.b $r0, [R_PORT_PA_DATA]
move.b CONFIG_ETRAX_DEF_R_PORT_PA_DIR, $r0
move.b $r0, [R_PORT_PA_DIR]
move.b CONFIG_ETRAX_DEF_R_PORT_PB_DATA, $r0
move.b $r0, [R_PORT_PB_DATA]
move.b CONFIG_ETRAX_DEF_R_PORT_PB_DIR, $r0
move.b $r0, [R_PORT_PB_DIR]
;; Setup the stack to a suitably high address.
;; We assume 8 MB is the minimum DRAM in an eLinux
;; product and put the sp at the top for now.
move.d 0x40800000, $sp
;; Figure out where the compressed piggyback image is
;; in the flash (since we wont try to copy it to DRAM
;; before unpacking). It is at _edata, but in flash.
;; Use (_edata - basse) as offset to the current PC.
basse: move.d $pc, $r5
and.d 0x7fffffff, $r5 ; strip any non-cache bit
subq 2, $r5 ; compensate for the move.d $pc instr
move.d $r5, $r0 ; save for later - flash address of 'basse'
add.d _edata, $r5
sub.d basse, $r5 ; $r5 = flash address of '_edata'
;; Copy text+data to DRAM
move.d basse, $r1 ; destination
move.d _edata, $r2 ; end destination
1: move.w [$r0+], $r3
move.w $r3, [$r1+]
cmp.d $r2, $r1
bcs 1b
nop
move.d $r5, [input_data] ; for the decompressor
;; Clear the decompressors BSS (between _edata and _end)
moveq 0, $r0
move.d _edata, $r1
move.d _end, $r2
1: move.w $r0, [$r1+]
cmp.d $r2, $r1
bcs 1b
nop
;; Save command line magic and address.
move.d _cmd_line_magic, $r12
move.d $r10, [$r12]
move.d _cmd_line_addr, $r12
move.d $r11, [$r12]
;; Do the decompression and save compressed size in inptr
jsr decompress_kernel
;; Put start address of root partition in $r9 so the kernel can use it
;; when mounting from flash
move.d [input_data], $r9 ; flash address of compressed kernel
add.d [inptr], $r9 ; size of compressed kernel
;; Restore command line magic and address.
move.d _cmd_line_magic, $r10
move.d [$r10], $r10
move.d _cmd_line_addr, $r11
move.d [$r11], $r11
;; Enter the decompressed kernel
move.d RAM_INIT_MAGIC, $r8 ; Tell kernel that DRAM is initialized
jump 0x40004000 ; kernel is linked to this address
.data
input_data:
.dword 0 ; used by the decompressor
_cmd_line_magic:
.dword 0
_cmd_line_addr:
.dword 0
#include "../../lib/hw_settings.S"
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