Root/target/linux/brcm63xx/image/lzma-loader/src/decompress.c

1/*
2 * LZMA compressed kernel decompressor for bcm947xx boards
3 *
4 * Copyright (C) 2005 by Oleg I. Vdovikin <oleg@cs.msu.su>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 *
20 *
21 * Please note, this was code based on the bunzip2 decompressor code
22 * by Manuel Novoa III (mjn3@codepoet.org), although the only thing left
23 * is an idea and part of original vendor code
24 *
25 *
26 * 12-Mar-2005 Mineharu Takahara <mtakahar@yahoo.com>
27 * pass actual output size to decoder (stream mode
28 * compressed input is not a requirement anymore)
29 *
30 * 24-Apr-2005 Oleg I. Vdovikin
31 * reordered functions using lds script, removed forward decl
32 *
33 */
34
35#include "LzmaDecode.h"
36
37#define BCM4710_FLASH 0x1fc00000 /* Flash */
38
39#define KSEG0 0x80000000
40#define KSEG1 0xa0000000
41
42#define KSEG1ADDR(a) ((((unsigned)(a)) & 0x1fffffffU) | KSEG1)
43
44#define Index_Invalidate_I 0x00
45#define Index_Writeback_Inv_D 0x01
46
47#define cache_unroll(base,op) \
48    __asm__ __volatile__( \
49        ".set noreorder;\n" \
50        ".set mips3;\n" \
51        "cache %1, (%0);\n" \
52        ".set mips0;\n" \
53        ".set reorder\n" \
54        : \
55        : "r" (base), \
56          "i" (op));
57
58static __inline__ void blast_icache(unsigned long size, unsigned long lsize)
59{
60    unsigned long start = KSEG0;
61    unsigned long end = (start + size);
62
63    while(start < end) {
64        cache_unroll(start,Index_Invalidate_I);
65        start += lsize;
66    }
67}
68
69static __inline__ void blast_dcache(unsigned long size, unsigned long lsize)
70{
71    unsigned long start = KSEG0;
72    unsigned long end = (start + size);
73
74    while(start < end) {
75        cache_unroll(start,Index_Writeback_Inv_D);
76        start += lsize;
77    }
78}
79
80#define TRX_MAGIC 0x30524448 /* "HDR0" */
81
82struct trx_header {
83    unsigned int magic; /* "HDR0" */
84    unsigned int len; /* Length of file including header */
85    unsigned int crc32; /* 32-bit CRC from flag_version to end of file */
86    unsigned int flag_version; /* 0:15 flags, 16:31 version */
87    unsigned int offsets[3]; /* Offsets of partitions from start of header */
88};
89
90/* beyound the image end, size not known in advance */
91extern unsigned char workspace[];
92
93unsigned int offset;
94unsigned char *data;
95
96/* flash access should be aligned, so wrapper is used */
97/* read byte from the flash, all accesses are 32-bit aligned */
98static int read_byte(void *object, unsigned char **buffer, UInt32 *bufferSize)
99{
100    static unsigned int val;
101
102    if (((unsigned int)offset % 4) == 0) {
103        val = *(unsigned int *)data;
104        data += 4;
105    }
106    
107    *bufferSize = 1;
108    *buffer = ((unsigned char *)&val) + (offset++ & 3);
109    
110    return LZMA_RESULT_OK;
111}
112
113static __inline__ unsigned char get_byte(void)
114{
115    unsigned char *buffer;
116    UInt32 fake;
117    
118    return read_byte(0, &buffer, &fake), *buffer;
119}
120
121/* should be the first function */
122void entry(unsigned long icache_size, unsigned long icache_lsize,
123    unsigned long dcache_size, unsigned long dcache_lsize)
124{
125    unsigned int i; /* temp value */
126    unsigned int lc; /* literal context bits */
127    unsigned int lp; /* literal pos state bits */
128    unsigned int pb; /* pos state bits */
129    unsigned int osize; /* uncompressed size */
130
131    ILzmaInCallback callback;
132    callback.Read = read_byte;
133
134    /* look for trx header, 32-bit data access */
135    for (data = ((unsigned char *) KSEG1ADDR(BCM4710_FLASH));
136        ((struct trx_header *)data)->magic != TRX_MAGIC; data += 65536);
137
138    /* compressed kernel is in the partition 0 or 1 */
139    if (((struct trx_header *)data)->offsets[1] > 65536)
140        data += ((struct trx_header *)data)->offsets[0];
141    else
142        data += ((struct trx_header *)data)->offsets[1];
143
144    offset = 0;
145
146    /* lzma args */
147    i = get_byte();
148    lc = i % 9, i = i / 9;
149    lp = i % 5, pb = i / 5;
150
151    /* skip rest of the LZMA coder property */
152    for (i = 0; i < 4; i++)
153        get_byte();
154
155    /* read the lower half of uncompressed size in the header */
156    osize = ((unsigned int)get_byte()) +
157        ((unsigned int)get_byte() << 8) +
158        ((unsigned int)get_byte() << 16) +
159        ((unsigned int)get_byte() << 24);
160
161    /* skip rest of the header (upper half of uncompressed size) */
162    for (i = 0; i < 4; i++)
163        get_byte();
164
165    /* decompress kernel */
166    if (LzmaDecode(workspace, ~0, lc, lp, pb, &callback,
167        (unsigned char*)LOADADDR, osize, &i) == LZMA_RESULT_OK)
168    {
169        blast_dcache(dcache_size, dcache_lsize);
170        blast_icache(icache_size, icache_lsize);
171
172        /* Jump to load address */
173        ((void (*)(void)) LOADADDR)();
174    }
175}
176

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