openwrt/target/linux/image/brcm/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
  58 static __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
  69 static __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
  82 struct 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 */
  91 extern unsigned char workspace[];
  92
  93 unsigned int offset;
  94 unsigned 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 */
  98 static 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
 113 static __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 */
 122 void 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 }