target/linux/adm5120/files/drivers/mtd/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   0x1     /* do not write TRX header */
  42 #define TRX_GZ_FILES    0x2     /* contains 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 */
  52 };
  53
  54 #define BLOCK_LEN_MIN           0x10000
  55
  56 static int trx_nr_parts;
  57 static unsigned long trx_offset;
  58 static struct mtd_info *trx_mtd;
  59 static struct mtd_partition trx_parts[TRX_MAX_OFFSET];
  60 static struct trx_header trx_hdr;
  61
  62 static int trxsplit_refresh_partitions(struct mtd_info *mtd);
  63
  64 static int trxsplit_checktrx(struct mtd_info *mtd, unsigned long offset)
  65 {
  66         size_t retlen;
  67         int err;
  68
  69         err = mtd->read(mtd, offset, sizeof(trx_hdr), &retlen,
  70                         (void *)&trx_hdr);
  71         if (err) {
  72                 printk(KERN_ALERT PFX "unable to read from '%s'\n", mtd->name);
  73                 goto err_out;
  74         }
  75
  76         if (retlen != sizeof(trx_hdr)) {
  77                 printk(KERN_ALERT PFX "reading failed on '%s'\n", mtd->name);
  78                 goto err_out;
  79         }
  80
  81         trx_hdr.magic = le32_to_cpu(trx_hdr.magic);
  82         trx_hdr.len = le32_to_cpu(trx_hdr.len);
  83         trx_hdr.crc32 = le32_to_cpu(trx_hdr.crc32);
  84         trx_hdr.flag_version = le32_to_cpu(trx_hdr.flag_version);
  85         trx_hdr.offsets[0] = le32_to_cpu(trx_hdr.offsets[0]);
  86         trx_hdr.offsets[1] = le32_to_cpu(trx_hdr.offsets[1]);
  87         trx_hdr.offsets[2] = le32_to_cpu(trx_hdr.offsets[2]);
  88
  89         /* sanity checks */
  90         if (trx_hdr.magic != TRX_MAGIC)
  91                 goto err_out;
  92
  93         if (trx_hdr.len > mtd->size - offset)
  94                 goto err_out;
  95
  96         /* TODO: add crc32 checking too? */
  97
  98         return 0;
  99
 100 err_out:
 101         return -1;
 102 }
 103
 104 static void trxsplit_findtrx(struct mtd_info *mtd)
 105 {
 106         unsigned long offset;
 107         unsigned long blocklen;
 108         int err;
 109
 110         blocklen = mtd->erasesize;
 111         if (blocklen < BLOCK_LEN_MIN)
 112                 blocklen = BLOCK_LEN_MIN;
 113
 114         printk(KERN_INFO PFX "searching TRX header in '%s'\n", mtd->name);
 115
 116         err = 0;
 117         for (offset = 0; offset < mtd->size; offset += blocklen) {
 118                 err = trxsplit_checktrx(mtd, offset);
 119                 if (err == 0)
 120                         break;
 121         }
 122
 123         if (err)
 124                 return;
 125
 126         printk(KERN_INFO PFX "TRX header found at 0x%lX\n", offset);
 127
 128         trx_mtd = mtd;
 129         trx_offset = offset;
 130 }
 131
 132 static void trxsplit_create_partitions(struct mtd_info *mtd)
 133 {
 134         struct mtd_partition *part = trx_parts;
 135         int err;
 136         int i;
 137
 138         for (i = 0; i < TRX_MAX_OFFSET; i++) {
 139                 part = &trx_parts[i];
 140                 if (trx_hdr.offsets[i] == 0)
 141                         continue;
 142                 part->offset = trx_offset + trx_hdr.offsets[i];
 143                 trx_nr_parts++;
 144         }
 145
 146         for (i = 0; i < trx_nr_parts-1; i++)
 147                 trx_parts[i].size = trx_parts[i+1].offset - trx_parts[i].offset;
 148
 149         trx_parts[i].size = mtd->size - trx_parts[i].offset;
 150
 151         i = 0;
 152         part = &trx_parts[i];
 153         if (part->size < TRX_MIN_KERNEL_SIZE) {
 154                 part->name = "loader";
 155                 i++;
 156         }
 157
 158         part = &trx_parts[i];
 159         part->name = "kernel";
 160         i++;
 161
 162         part = &trx_parts[i];
 163         part->name = "rootfs";
 164
 165         err = add_mtd_partitions(mtd, trx_parts, trx_nr_parts);
 166         if (err) {
 167                 printk(KERN_ALERT PFX "adding TRX partitions failed\n");
 168                 return;
 169         }
 170
 171         mtd->refresh_device = trxsplit_refresh_partitions;
 172 }
 173
 174 static int trxsplit_refresh_partitions(struct mtd_info *mtd)
 175 {
 176         printk(KERN_INFO PFX "refreshing TRX partitions in '%s' (%d,%d)\n",
 177                 mtd->name, MTD_BLOCK_MAJOR, mtd->index);
 178
 179         /* remove old partitions */
 180         del_mtd_partitions(mtd);
 181
 182         trxsplit_findtrx(mtd);
 183         if (!trx_mtd)
 184                 goto err;
 185
 186         trxsplit_create_partitions(trx_mtd);
 187         return 1;
 188
 189 err:
 190         return 0;
 191 }
 192
 193 static void __init trxsplit_add_mtd(struct mtd_info *mtd)
 194 {
 195         if (!trx_mtd)
 196                 trxsplit_findtrx(mtd);
 197 }
 198
 199 static void __init trxsplit_remove_mtd(struct mtd_info *mtd)
 200 {
 201         /* nothing to do */
 202 }
 203
 204 static struct mtd_notifier trxsplit_notifier __initdata = {
 205         .add    = trxsplit_add_mtd,
 206         .remove = trxsplit_remove_mtd,
 207 };
 208
 209 static void __init trxsplit_scan(void)
 210 {
 211         register_mtd_user(&trxsplit_notifier);
 212         unregister_mtd_user(&trxsplit_notifier);
 213 }
 214
 215 static int __init trxsplit_init(void)
 216 {
 217         trxsplit_scan();
 218
 219         if (trx_mtd) {
 220                 printk(KERN_INFO PFX "creating TRX partitions in '%s' "
 221                         "(%d,%d)\n", trx_mtd->name, MTD_BLOCK_MAJOR,
 222                         trx_mtd->index);
 223                 trxsplit_create_partitions(trx_mtd);
 224         }
 225
 226         return 0;
 227 }
 228
 229 late_initcall(trxsplit_init);