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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/cris/boot/compressed/head_v10.S
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/*

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 *  arch/cris/boot/compressed/head.S

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 *

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 *  Copyright (C) 1999, 2001 Axis Communications AB

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 *

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 *  Code that sets up the DRAM registers, calls the

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 *  decompressor to unpack the piggybacked kernel, and jumps.

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 *

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 */

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#define ASSEMBLER_MACROS_ONLY

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#include <arch/sv_addr_ag.h>

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#define RAM_INIT_MAGIC 0x56902387

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#define COMMAND_LINE_MAGIC 0x87109563

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	;; Exported symbols

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	.globl	input_data

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	.text

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	nop

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	di

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;; We need to initialze DRAM registers before we start using the DRAM

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	cmp.d	RAM_INIT_MAGIC, $r8	; Already initialized?

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	beq	dram_init_finished

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	nop

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#include "../../arch-v10/lib/dram_init.S"

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dram_init_finished:

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	;; Initiate the PA and PB ports

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	move.b   CONFIG_ETRAX_DEF_R_PORT_PA_DATA, $r0

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	move.b   $r0, [R_PORT_PA_DATA]

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	move.b   CONFIG_ETRAX_DEF_R_PORT_PA_DIR, $r0

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	move.b   $r0, [R_PORT_PA_DIR]

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	move.b   CONFIG_ETRAX_DEF_R_PORT_PB_DATA, $r0

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	move.b   $r0, [R_PORT_PB_DATA]

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	move.b   CONFIG_ETRAX_DEF_R_PORT_PB_DIR, $r0

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	move.b   $r0, [R_PORT_PB_DIR]

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	;; Setup the stack to a suitably high address.

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	;; We assume 8 MB is the minimum DRAM in an eLinux

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	;; product and put the sp at the top for now.

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	move.d	0x40800000, $sp

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	;; Figure out where the compressed piggyback image is

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	;; in the flash (since we wont try to copy it to DRAM

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	;; before unpacking). It is at _edata, but in flash.

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	;; Use (_edata - basse) as offset to the current PC.

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basse:	move.d	$pc, $r5

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	and.d	0x7fffffff, $r5	; strip any non-cache bit

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	subq	2, $r5		; compensate for the move.d $pc instr

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	move.d	$r5, $r0		; save for later - flash address of 'basse'

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	add.d	_edata, $r5

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	sub.d	basse, $r5	; $r5 = flash address of '_edata'

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	;; Copy text+data to DRAM

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	move.d	basse, $r1	; destination

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	move.d	_edata, $r2	; end destination

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1:	move.w	[$r0+], $r3

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	move.w	$r3, [$r1+]

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	cmp.d	$r2, $r1

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	bcs	1b

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	nop

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	move.d	$r5, [input_data] ; for the decompressor

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	;; Clear the decompressors BSS (between _edata and _end)

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	moveq	0, $r0

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	move.d	_edata, $r1

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	move.d	_end, $r2

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1:	move.w	$r0, [$r1+]

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	cmp.d	$r2, $r1

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	bcs	1b

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	nop

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	;;  Save command line magic and address.

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	move.d	_cmd_line_magic, $r12

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	move.d  $r10, [$r12]

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	move.d	_cmd_line_addr, $r12

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	move.d  $r11, [$r12]

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	;; Do the decompression and save compressed size in inptr

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	jsr	decompress_kernel

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	;; Put start address of root partition in $r9 so the kernel can use it

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	;; when mounting from flash

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	move.d	[input_data], $r9	; flash address of compressed kernel

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	add.d	[inptr], $r9		; size of compressed kernel

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	;; Restore command line magic and address.

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	move.d  _cmd_line_magic, $r10

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	move.d  [$r10], $r10

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	move.d  _cmd_line_addr, $r11

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	move.d  [$r11], $r11

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	;; Enter the decompressed kernel

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	move.d	RAM_INIT_MAGIC, $r8	; Tell kernel that DRAM is initialized

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	jump	0x40004000	; kernel is linked to this address

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	.data

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input_data:

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	.dword	0		; used by the decompressor

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_cmd_line_magic:

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	.dword 0

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_cmd_line_addr:

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	.dword 0

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#include "../../arch-v10/lib/hw_settings.S"

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