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@freemail.hu>
   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_master = NULL;
  57 static struct mtd_info *trx_mtds[TRX_MAX_OFFSET];
  58 static struct mtd_partition trx_parts[TRX_MAX_OFFSET];
  59 static struct trx_header trx_hdr;
  60 static int trx_nr_parts = 0;
  61 static int trx_rootfs_part = -1;
  62
  63 static int __init trxsplit_checktrx(struct mtd_info *mtd, unsigned long offset)
  64 {
  65         size_t retlen;
  66         int err;
  67
  68         err = mtd->read(mtd, offset, sizeof(trx_hdr), &retlen, (void *)&trx_hdr);
  69         if (err)
  70                 goto err_out;
  71
  72         if (retlen != sizeof(trx_hdr))
  73                 goto err_out;
  74
  75         trx_hdr.magic = le32_to_cpu(trx_hdr.magic);
  76         trx_hdr.len = le32_to_cpu(trx_hdr.len);
  77         trx_hdr.crc32 = le32_to_cpu(trx_hdr.crc32);
  78         trx_hdr.flag_version = le32_to_cpu(trx_hdr.flag_version);
  79         trx_hdr.offsets[0] = le32_to_cpu(trx_hdr.offsets[0]);
  80         trx_hdr.offsets[1] = le32_to_cpu(trx_hdr.offsets[1]);
  81         trx_hdr.offsets[2] = le32_to_cpu(trx_hdr.offsets[2]);
  82
  83         /* sanity checks */
  84         if (trx_hdr.magic != TRX_MAGIC)
  85                 goto err_out;
  86
  87         if (trx_hdr.len > mtd->size - offset)
  88                 goto err_out;
  89
  90         /* TODO: add crc32 checking too? */
  91
  92         return 1;
  93
  94 err_out:
  95         return 0;
  96 }
  97
  98 static void __init trxsplit_create_partitions(struct mtd_info *mtd,
  99         unsigned long offset)
 100 {
 101         struct mtd_partition *part = trx_parts;
 102         int i;
 103
 104         for (i=0;i<TRX_MAX_OFFSET;i++) {
 105                 part = &trx_parts[i];
 106                 if (trx_hdr.offsets[i] == 0)
 107                         continue;
 108                 part->offset = offset + trx_hdr.offsets[i];
 109                 part->mtdp = &trx_mtds[trx_nr_parts];
 110                 trx_nr_parts++;
 111         }
 112
 113         for (i=0; i<trx_nr_parts-1; i++) {
 114                 trx_parts[i].size = trx_parts[i+1].offset - trx_parts[i].offset;
 115         }
 116         trx_parts[i].size = mtd->size - trx_parts[i].offset;
 117
 118         i=0;
 119         part = &trx_parts[i];
 120         if (part->size < TRX_MIN_KERNEL_SIZE) {
 121                 part->name = "trx_loader";
 122                 i++;
 123         }
 124
 125         part = &trx_parts[i];
 126         part->name = "trx_kernel";
 127         i++;
 128
 129         part = &trx_parts[i];
 130         part->name = "trx_rootfs";
 131         trx_rootfs_part = i;
 132 }
 133
 134 static void __init trxsplit_add_mtd(struct mtd_info *mtd)
 135 {
 136         unsigned long offset;
 137         unsigned long blocklen;
 138         int found;
 139
 140         if (trx_mtd_master)
 141                 return;
 142
 143         blocklen = mtd->erasesize;
 144         if (blocklen < BLOCK_LEN_MIN)
 145                 blocklen = BLOCK_LEN_MIN;
 146
 147         printk(KERN_INFO PFX "searching TRX header in '%s'\n", mtd->name);
 148
 149         found = 0;
 150         for (offset=0; offset < mtd->size; offset+=blocklen) {
 151                 found = trxsplit_checktrx(mtd, offset);
 152                 if (found)
 153                         break;
 154         }
 155
 156         if (found == 0) {
 157                 printk(KERN_ALERT PFX "no TRX header found\n");
 158                 return;
 159         }
 160
 161         printk(KERN_INFO PFX "TRX header found at 0x%lX\n", offset);
 162
 163         trxsplit_create_partitions(mtd, offset);
 164
 165         trx_mtd_master = mtd;
 166 }
 167
 168 static void trxsplit_remove_mtd(struct mtd_info *mtd)
 169 {
 170 }
 171
 172 static struct mtd_notifier trxsplit_notifier __initdata = {
 173         .add    = trxsplit_add_mtd,
 174         .remove = trxsplit_remove_mtd,
 175 };
 176
 177 static void __init trxsplit_find_trx(void)
 178 {
 179         register_mtd_user(&trxsplit_notifier);
 180         unregister_mtd_user(&trxsplit_notifier);
 181 }
 182
 183 static int __init trxsplit_init(void)
 184 {
 185         int err;
 186         int i;
 187
 188         trxsplit_find_trx();
 189
 190         if (trx_mtd_master == NULL)
 191                 goto err;
 192
 193         printk(KERN_INFO PFX "creating TRX partitions in '%s'\n",
 194                 trx_mtd_master->name);
 195
 196         err = add_mtd_partitions(trx_mtd_master, trx_parts, trx_nr_parts);
 197         if (err) {
 198                 printk(KERN_ALERT PFX "creating TRX partitions failed\n");
 199                 goto err;
 200         }
 201
 202         for (i=0; i<trx_nr_parts; i++) {
 203                 /* TODO: add error checking */
 204                 add_mtd_device(trx_mtds[i]);
 205         }
 206
 207         if (ROOT_DEV == 0 && trx_rootfs_part >= 0) {
 208                 printk(KERN_INFO PFX "set '%s' to be root filesystem\n",
 209                         trx_mtds[trx_rootfs_part]->name);
 210                 ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, trx_mtds[trx_rootfs_part]->index);
 211         }
 212
 213         return 0;
 214
 215 err:
 216         return -1;
 217 }
 218
 219 late_initcall(trxsplit_init);