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   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 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, (void *)&trx_hdr);
  70         if (err) {
  71                 printk(KERN_ALERT PFX "unable to read from '%s'\n", mtd->name);
  72                 goto err_out;
  73         }
  74
  75         if (retlen != sizeof(trx_hdr)) {
  76                 printk(KERN_ALERT PFX "reading failed on '%s'\n", mtd->name);
  77                 goto err_out;
  78         }
  79
  80         trx_hdr.magic = le32_to_cpu(trx_hdr.magic);
  81         trx_hdr.len = le32_to_cpu(trx_hdr.len);
  82         trx_hdr.crc32 = le32_to_cpu(trx_hdr.crc32);
  83         trx_hdr.flag_version = le32_to_cpu(trx_hdr.flag_version);
  84         trx_hdr.offsets[0] = le32_to_cpu(trx_hdr.offsets[0]);
  85         trx_hdr.offsets[1] = le32_to_cpu(trx_hdr.offsets[1]);
  86         trx_hdr.offsets[2] = le32_to_cpu(trx_hdr.offsets[2]);
  87
  88         /* sanity checks */
  89         if (trx_hdr.magic != TRX_MAGIC)
  90                 goto err_out;
  91
  92         if (trx_hdr.len > mtd->size - offset)
  93                 goto err_out;
  94
  95         /* TODO: add crc32 checking too? */
  96
  97         return 0;
  98
  99 err_out:
 100         return -1;
 101 }
 102
 103 static void trxsplit_findtrx(struct mtd_info *mtd)
 104 {
 105         unsigned long offset;
 106         unsigned long blocklen;
 107         int err;
 108
 109         blocklen = mtd->erasesize;
 110         if (blocklen < BLOCK_LEN_MIN)
 111                 blocklen = BLOCK_LEN_MIN;
 112
 113         printk(KERN_INFO PFX "searching TRX header in '%s'\n", mtd->name);
 114
 115         err = 0;
 116         for (offset=0; offset < mtd->size; offset+=blocklen) {
 117                 err = trxsplit_checktrx(mtd, offset);
 118                 if (err == 0)
 119                         break;
 120         }
 121
 122         if (err)
 123                 return;
 124
 125         printk(KERN_INFO PFX "TRX header found at 0x%lX\n", offset);
 126
 127         trx_mtd = mtd;
 128         trx_offset = offset;
 129 }
 130
 131 static void trxsplit_create_partitions(struct mtd_info *mtd)
 132 {
 133         struct mtd_partition *part = trx_parts;
 134         int err;
 135         int i;
 136
 137         for (i=0; i<TRX_MAX_OFFSET;i++) {
 138                 part = &trx_parts[i];
 139                 if (trx_hdr.offsets[i] == 0)
 140                         continue;
 141                 part->offset = trx_offset + trx_hdr.offsets[i];
 142                 trx_nr_parts++;
 143         }
 144
 145         for (i=0; i<trx_nr_parts-1; i++) {
 146                 trx_parts[i].size = trx_parts[i+1].offset - trx_parts[i].offset;
 147         }
 148         trx_parts[i].size = mtd->size - trx_parts[i].offset;
 149
 150         i=0;
 151         part = &trx_parts[i];
 152         if (part->size < TRX_MIN_KERNEL_SIZE) {
 153                 part->name = "loader";
 154                 i++;
 155         }
 156
 157         part = &trx_parts[i];
 158         part->name = "kernel";
 159         i++;
 160
 161         part = &trx_parts[i];
 162         part->name = "rootfs";
 163
 164         err = add_mtd_partitions(mtd, trx_parts, trx_nr_parts);
 165         if (err) {
 166                 printk(KERN_ALERT PFX "adding TRX partitions failed\n");
 167                 return;
 168         }
 169
 170         mtd->refresh_device = trxsplit_refresh_partitions;
 171 }
 172
 173 static int trxsplit_refresh_partitions(struct mtd_info *mtd)
 174 {
 175         printk(KERN_INFO PFX "refreshing TRX partitions in '%s' (%d,%d)\n",
 176                 mtd->name, MTD_BLOCK_MAJOR, mtd->index);
 177
 178         /* remove old partitions */
 179         del_mtd_partitions(mtd);
 180
 181         trxsplit_findtrx(mtd);
 182         if (!trx_mtd)
 183                 goto err;
 184
 185         trxsplit_create_partitions(trx_mtd);
 186         return 1;
 187
 188 err:
 189         return 0;
 190 }
 191
 192 static void __init trxsplit_add_mtd(struct mtd_info *mtd)
 193 {
 194         if (!trx_mtd)
 195                 trxsplit_findtrx(mtd);
 196 }
 197
 198 static void __init trxsplit_remove_mtd(struct mtd_info *mtd)
 199 {
 200         /* nothing to do */
 201 }
 202
 203 static struct mtd_notifier trxsplit_notifier __initdata = {
 204         .add    = trxsplit_add_mtd,
 205         .remove = trxsplit_remove_mtd,
 206 };
 207
 208 static void __init trxsplit_scan(void)
 209 {
 210         register_mtd_user(&trxsplit_notifier);
 211         unregister_mtd_user(&trxsplit_notifier);
 212 }
 213
 214 static int __init trxsplit_init(void)
 215 {
 216         trxsplit_scan();
 217
 218         if (trx_mtd) {
 219                 printk(KERN_INFO PFX "creating TRX partitions in '%s' (%d,%d)\n",
 220                         trx_mtd->name, MTD_BLOCK_MAJOR, trx_mtd->index);
 221                 trxsplit_create_partitions(trx_mtd);
 222         }
 223
 224         return 0;
 225 }
 226
 227 late_initcall(trxsplit_init);