target/linux/adm5120-2.6/files/arch/mips/adm5120/trxsplit.c

   1 /*
   2  *  $Id$
   3  *
   4  *  Copyright (C) 2007 OpenWrt.org
   5  *  Copyright (C) Gabor Juhos <juhosg at openwrt.org>
   6  *
   7  *  This program is free software; you can redistribute it and/or
   8  *  modify it under the terms of the GNU General Public License
   9  *  as published by the Free Software Foundation; either version 2
  10  *  of the License, or (at your option) any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with this program; if not, write to the
  19  *  Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20  *  Boston, MA  02110-1301, USA.
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/types.h>
  25 #include <linux/kernel.h>
  26 #include <linux/slab.h>
  27 #include <linux/list.h>
  28 #include <linux/kmod.h>
  29 #include <linux/root_dev.h>
  30
  31 #include <linux/mtd/mtd.h>
  32 #include <linux/mtd/partitions.h>
  33
  34 #include <linux/byteorder/generic.h>
  35
  36 #define PFX     "trxsplit: "
  37
  38 #define TRX_MAGIC       0x30524448      /* "HDR0" */
  39 #define TRX_VERSION     1
  40 #define TRX_MAX_LEN     0x3A0000
  41 #define TRX_NO_HEADER   1               /* Do not write TRX header */
  42 #define TRX_GZ_FILES    0x2     /* Contains up to TRX_MAX_OFFSET individual gzip files */
  43 #define TRX_MAX_OFFSET  3
  44 #define TRX_MIN_KERNEL_SIZE     256*1024
  45
  46 struct trx_header {
  47         u32 magic;              /* "HDR0" */
  48         u32 len;                /* Length of file including header */
  49         u32 crc32;              /* 32-bit CRC from flag_version to end of file */
  50         u32 flag_version;       /* 0:15 flags, 16:31 version */
  51         u32 offsets[TRX_MAX_OFFSET];    /* Offsets of partitions from start of header */
  52 };
  53
  54 #define BLOCK_LEN_MIN           0x10000
  55
  56 static struct mtd_info *trx_mtd = NULL;
  57 static unsigned long trx_offset = 0;
  58 static int trx_nr_parts = 0;
  59 static struct mtd_partition trx_parts[TRX_MAX_OFFSET];
  60 static struct trx_header trx_hdr;
  61
  62 static int __init trxsplit_checktrx(struct mtd_info *mtd, unsigned long offset)
  63 {
  64         size_t retlen;
  65         int err;
  66
  67         err = mtd->read(mtd, offset, sizeof(trx_hdr), &retlen, (void *)&trx_hdr);
  68         if (err) {
  69                 printk(KERN_ALERT PFX "unable to read from '%s'\n", mtd->name);
  70                 goto err_out;
  71         }
  72
  73         if (retlen != sizeof(trx_hdr)) {
  74                 printk(KERN_ALERT PFX "reading failed on '%s'\n", mtd->name);
  75                 goto err_out;
  76         }
  77
  78         trx_hdr.magic = le32_to_cpu(trx_hdr.magic);
  79         trx_hdr.len = le32_to_cpu(trx_hdr.len);
  80         trx_hdr.crc32 = le32_to_cpu(trx_hdr.crc32);
  81         trx_hdr.flag_version = le32_to_cpu(trx_hdr.flag_version);
  82         trx_hdr.offsets[0] = le32_to_cpu(trx_hdr.offsets[0]);
  83         trx_hdr.offsets[1] = le32_to_cpu(trx_hdr.offsets[1]);
  84         trx_hdr.offsets[2] = le32_to_cpu(trx_hdr.offsets[2]);
  85
  86         /* sanity checks */
  87         if (trx_hdr.magic != TRX_MAGIC)
  88                 goto err_out;
  89
  90         if (trx_hdr.len > mtd->size - offset)
  91                 goto err_out;
  92
  93         /* TODO: add crc32 checking too? */
  94
  95         return 0;
  96
  97 err_out:
  98         return -1;
  99 }
 100
 101 static int __init trxsplit_create_partitions(void)
 102 {
 103         struct mtd_partition *part = trx_parts;
 104         int ret = 0;
 105         int i;
 106
 107         if (trx_mtd == NULL)
 108                 goto out;
 109
 110         printk(KERN_INFO PFX "creating TRX partitions in '%s' (%d,%d)\n",
 111                 trx_mtd->name, MTD_BLOCK_MAJOR, trx_mtd->index);
 112
 113         for (i=0; i<TRX_MAX_OFFSET;i++) {
 114                 part = &trx_parts[i];
 115                 if (trx_hdr.offsets[i] == 0)
 116                         continue;
 117                 part->offset = trx_offset + trx_hdr.offsets[i];
 118                 trx_nr_parts++;
 119         }
 120
 121         for (i=0; i<trx_nr_parts-1; i++) {
 122                 trx_parts[i].size = trx_parts[i+1].offset - trx_parts[i].offset;
 123         }
 124         trx_parts[i].size = trx_mtd->size - trx_parts[i].offset;
 125
 126         i=0;
 127         part = &trx_parts[i];
 128         if (part->size < TRX_MIN_KERNEL_SIZE) {
 129                 part->name = "loader";
 130                 i++;
 131         }
 132
 133         part = &trx_parts[i];
 134         part->name = "kernel";
 135         i++;
 136
 137         part = &trx_parts[i];
 138         part->name = "rootfs";
 139
 140         ret = add_mtd_partitions(trx_mtd, trx_parts, trx_nr_parts);
 141         if (ret) {
 142                 printk(KERN_ALERT PFX "creating TRX partitions failed\n");
 143         }
 144
 145 out:
 146         return ret;
 147 }
 148
 149 static void __init trxsplit_add_mtd(struct mtd_info *mtd)
 150 {
 151         unsigned long offset;
 152         unsigned long blocklen;
 153         int err;
 154
 155         if (trx_mtd)
 156                 return;
 157
 158         blocklen = mtd->erasesize;
 159         if (blocklen < BLOCK_LEN_MIN)
 160                 blocklen = BLOCK_LEN_MIN;
 161
 162         printk(KERN_INFO PFX "searching TRX header in '%s'\n", mtd->name);
 163
 164         err = 0;
 165         for (offset=0; offset < mtd->size; offset+=blocklen) {
 166                 err = trxsplit_checktrx(mtd, offset);
 167                 if (err == 0)
 168                         break;
 169         }
 170
 171         if (err) {
 172                 printk(KERN_ALERT PFX "no TRX header found\n");
 173                 return;
 174         }
 175
 176         printk(KERN_INFO PFX "TRX header found at 0x%lX\n", offset);
 177
 178         trx_mtd = mtd;
 179         trx_offset = offset;
 180 }
 181
 182 static void __init trxsplit_remove_mtd(struct mtd_info *mtd)
 183 {
 184         /* nothing to do */
 185 }
 186
 187 static struct mtd_notifier trxsplit_notifier __initdata = {
 188         .add    = trxsplit_add_mtd,
 189         .remove = trxsplit_remove_mtd,
 190 };
 191
 192 static void __init trxsplit_find_trx(void)
 193 {
 194         register_mtd_user(&trxsplit_notifier);
 195         unregister_mtd_user(&trxsplit_notifier);
 196 }
 197
 198 static int __init trxsplit_init(void)
 199 {
 200         int ret;
 201
 202         trxsplit_find_trx();
 203
 204         ret = trxsplit_create_partitions();
 205         return ret;
 206 }
 207
 208 late_initcall(trxsplit_init);