arch/cris/boot/compressed/head_v10.S

/*
 *  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 "../../arch-v10/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 "../../arch-v10/lib/hw_settings.S"