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/*
* Code that sets up the DRAM registers, calls the
* decompressor to unpack the piggybacked kernel, and jumps.
*
* Copyright (C) 1999 - 2006, Axis Communications AB
*/
#define ASSEMBLER_MACROS_ONLY
#include <hwregs/asm/reg_map_asm.h>
#include <mach/startup.inc>
#define RAM_INIT_MAGIC 0x56902387
#define COMMAND_LINE_MAGIC 0x87109563
;; Exported symbols
.globl input_data
.text
_start:
di
;; Start clocks for used blocks.
START_CLOCKS
;; Initialize the DRAM registers.
cmp.d RAM_INIT_MAGIC, $r8 ; Already initialized?
beq dram_init_finished
nop
#include "../../mach/dram_init.S"
dram_init_finished:
GIO_INIT
;; Setup the stack to a suitably high address.
;; We assume 8 MB is the minimum DRAM and put
;; the SP at the top for now.
move.d 0x40800000, $sp
;; Figure out where the compressed piggyback image is.
;; It is either in [NOR] flash (we don't want to copy it
;; to DRAM before unpacking), or copied to DRAM
;; by the [NAND] flash boot loader.
;; The piggyback image is at _edata, but relative to where the
;; image is actually located in memory, not where it is linked
;; (the decompressor is linked at 0x40700000+ and runs there).
;; Use (_edata - herami) as offset to the current PC.
hereami:
lapcq ., $r5 ; get PC
and.d 0x7fffffff, $r5 ; strip any non-cache bit
move.d $r5, $r0 ; source address of 'herami'
add.d _edata, $r5
sub.d hereami, $r5 ; r5 = flash address of '_edata'
move.d hereami, $r1 ; destination
;; Copy text+data to DRAM
move.d _edata, $r2 ; end destination
1: move.w [$r0+], $r3 ; from herami+ source
move.w $r3, [$r1+] ; to hereami+ destination (linked address)
cmp.d $r2, $r1 ; finish when destination == _edata
bcs 1b
nop
move.d input_data, $r0 ; for the decompressor
move.d $r5, [$r0] ; 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, $r0
move.d $r10, [$r0]
move.d _cmd_line_addr, $r0
move.d $r11, [$r0]
;; Save boot source indicator
move.d _boot_source, $r0
move.d $r12, [$r0]
;; Do the decompression and save compressed size in _inptr
jsr decompress_kernel
nop
;; Restore boot source indicator
move.d _boot_source, $r12
move.d [$r12], $r12
;; 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
;; Put start address of root partition in r9 so the kernel can use it
;; when mounting from flash
move.d input_data, $r0
move.d [$r0], $r9 ; flash address of compressed kernel
move.d inptr, $r0
add.d [$r0], $r9 ; size of compressed kernel
cmp.d 0x40000000, $r9 ; image in DRAM ?
blo enter_kernel ; no, must be [NOR] flash, jump
nop ; delay slot
and.d 0x001fffff, $r9 ; assume compressed kernel was < 2M
enter_kernel:
;; Enter the decompressed kernel
move.d RAM_INIT_MAGIC, $r8 ; Tell kernel that DRAM is initialized
jump 0x40004000 ; kernel is linked to this address
nop
.data
input_data:
.dword 0 ; used by the decompressor
_cmd_line_magic:
.dword 0
_cmd_line_addr:
.dword 0
_boot_source:
.dword 0
#include "../../mach/hw_settings.S"
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