1/*
2 *  arch/cris/boot/compressed/head.S
3 *
4 *  Copyright (C) 1999, 2001 Axis Communications AB
5 *
6 *  Code that sets up the DRAM registers, calls the
7 *  decompressor to unpack the piggybacked kernel, and jumps.
8 *
9 */
10
11#include <linux/config.h>
12#define ASSEMBLER_MACROS_ONLY
13#include <asm/sv_addr_ag.h>
14
15#define RAM_INIT_MAGIC 0x56902387
16
17	;; Exported symbols
18
19	.globl	_input_data
20
21
22	.text
23
24	nop
25	di
26
27;; We need to initialze DRAM registers before we start using the DRAM
28
29	cmp.d	RAM_INIT_MAGIC, r8	; Already initialized?
30	beq	dram_init_finished
31	nop
32
33#include "../../lib/dram_init.S"
34
35dram_init_finished:
36
37	;; Initiate the PA and PB ports
38
39	move.b   CONFIG_ETRAX_DEF_R_PORT_PA_DATA, r0
40	move.b   r0, [R_PORT_PA_DATA]
41
42	move.b   CONFIG_ETRAX_DEF_R_PORT_PA_DIR, r0
43	move.b   r0, [R_PORT_PA_DIR]
44
45	move.b   CONFIG_ETRAX_DEF_R_PORT_PB_DATA, r0
46	move.b   r0, [R_PORT_PB_DATA]
47
48	move.b   CONFIG_ETRAX_DEF_R_PORT_PB_DIR, r0
49	move.b   r0, [R_PORT_PB_DIR]
50
51	;; Setup the stack to a suitably high address.
52	;; We assume 8 MB is the minimum DRAM in an eLinux
53	;; product and put the sp at the top for now.
54
55	move.d	0x40800000, sp
56
57	;; Figure out where the compressed piggyback image is
58	;; in the flash (since we wont try to copy it to DRAM
59	;; before unpacking). It is at _edata, but in flash.
60	;; Use (_edata - basse) as offset to the current PC.
61
62basse:	move.d	pc, r5
63	and.d	0x7fffffff, r5	; strip any non-cache bit
64	subq	2, r5		; compensate for the move.d pc instr
65	move.d	r5, r0		; save for later - flash address of 'basse'
66	add.d	_edata, r5
67	sub.d	basse, r5	; r5 = flash address of '_edata'
68
69	;; Copy text+data to DRAM
70
71	move.d	basse, r1	; destination
72	move.d	_edata, r2	; end destination
731:	move.w	[r0+], r3
74	move.w	r3, [r1+]
75	cmp.d	r2, r1
76	bcs	1b
77	nop
78
79	move.d	r5, [_input_data] ; for the decompressor
80
81
82	;; Clear the decompressors BSS (between _edata and _end)
83
84	moveq	0, r0
85	move.d	_edata, r1
86	move.d	_end, r2
871:	move.w	r0, [r1+]
88	cmp.d	r2, r1
89	bcs	1b
90	nop
91
92	;; Do the decompression and save compressed size in _inptr
93
94	jsr	_decompress_kernel
95
96	;; Put start address of root partition in r9 so the kernel can use it
97	;; when mounting from flash
98
99	move.d	[_input_data], r9	; flash address of compressed kernel
100	add.d	[_inptr], r9		; size of compressed kernel
101
102	;; Enter the decompressed kernel
103	move.d	RAM_INIT_MAGIC, r8	; Tell kernel that DRAM is initialized
104	jump	0x40004000	; kernel is linked to this address
105
106	.data
107
108_input_data:
109	.dword	0		; used by the decompressor
110
111#include "../../lib/hw_settings.S"
112