target/linux/adm5120/files/drivers/mtd/trxsplit.c

   1 /*
   2  *  Copyright (C) Gabor Juhos <juhosg@openwrt.org>
   3  *
   4  *  This program is free software; you can redistribute it and/or modify it
   5  *  under the terms of the GNU General Public License version 2 as published
   6  *  by the Free Software Foundation.
   7  *
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/types.h>
  12 #include <linux/kernel.h>
  13 #include <linux/slab.h>
  14 #include <linux/list.h>
  15 #include <linux/kmod.h>
  16 #include <linux/root_dev.h>
  17
  18 #include <linux/mtd/mtd.h>
  19 #include <linux/mtd/partitions.h>
  20
  21 #include <linux/byteorder/generic.h>
  22
  23 #define PFX     "trxsplit: "
  24
  25 #define TRX_MAGIC       0x30524448      /* "HDR0" */
  26 #define TRX_VERSION     1
  27 #define TRX_MAX_LEN     0x3A0000
  28 #define TRX_NO_HEADER   0x1     /* do not write TRX header */
  29 #define TRX_GZ_FILES    0x2     /* contains individual gzip files */
  30 #define TRX_MAX_OFFSET  3
  31 #define TRX_MIN_KERNEL_SIZE     256*1024
  32
  33 struct trx_header {
  34         u32 magic;      /* "HDR0" */
  35         u32 len;        /* Length of file including header */
  36         u32 crc32;      /* 32-bit CRC from flag_version to end of file */
  37         u32 flag_version; /* 0:15 flags, 16:31 version */
  38         u32 offsets[TRX_MAX_OFFSET]; /* Offsets of partitions */
  39 };
  40
  41 #define TRX_ALIGN       0x1000
  42
  43 static int trx_nr_parts;
  44 static unsigned long trx_offset;
  45 static struct mtd_info *trx_mtd;
  46 static struct mtd_partition trx_parts[TRX_MAX_OFFSET];
  47 static struct trx_header trx_hdr;
  48
  49 static int trxsplit_refresh_partitions(struct mtd_info *mtd);
  50
  51 static int trxsplit_checktrx(struct mtd_info *mtd, unsigned long offset)
  52 {
  53         size_t retlen;
  54         int err;
  55
  56         err = mtd->read(mtd, offset, sizeof(trx_hdr), &retlen,
  57                         (void *)&trx_hdr);
  58         if (err) {
  59                 printk(KERN_ALERT PFX "unable to read from '%s'\n", mtd->name);
  60                 goto err_out;
  61         }
  62
  63         if (retlen != sizeof(trx_hdr)) {
  64                 printk(KERN_ALERT PFX "reading failed on '%s'\n", mtd->name);
  65                 goto err_out;
  66         }
  67
  68         trx_hdr.magic = le32_to_cpu(trx_hdr.magic);
  69         trx_hdr.len = le32_to_cpu(trx_hdr.len);
  70         trx_hdr.crc32 = le32_to_cpu(trx_hdr.crc32);
  71         trx_hdr.flag_version = le32_to_cpu(trx_hdr.flag_version);
  72         trx_hdr.offsets[0] = le32_to_cpu(trx_hdr.offsets[0]);
  73         trx_hdr.offsets[1] = le32_to_cpu(trx_hdr.offsets[1]);
  74         trx_hdr.offsets[2] = le32_to_cpu(trx_hdr.offsets[2]);
  75
  76         /* sanity checks */
  77         if (trx_hdr.magic != TRX_MAGIC)
  78                 goto err_out;
  79
  80         if (trx_hdr.len > mtd->size - offset)
  81                 goto err_out;
  82
  83         /* TODO: add crc32 checking too? */
  84
  85         return 0;
  86
  87 err_out:
  88         return -1;
  89 }
  90
  91 static void trxsplit_findtrx(struct mtd_info *mtd)
  92 {
  93         unsigned long offset;
  94         int err;
  95
  96         printk(KERN_INFO PFX "searching TRX header in '%s'\n", mtd->name);
  97
  98         err = 0;
  99         for (offset = 0; offset < mtd->size; offset += TRX_ALIGN) {
 100                 err = trxsplit_checktrx(mtd, offset);
 101                 if (err == 0)
 102                         break;
 103         }
 104
 105         if (err)
 106                 return;
 107
 108         printk(KERN_INFO PFX "TRX header found at 0x%lX\n", offset);
 109
 110         trx_mtd = mtd;
 111         trx_offset = offset;
 112 }
 113
 114 static void trxsplit_create_partitions(struct mtd_info *mtd)
 115 {
 116         struct mtd_partition *part = trx_parts;
 117         int err;
 118         int i;
 119
 120         for (i = 0; i < TRX_MAX_OFFSET; i++) {
 121                 part = &trx_parts[i];
 122                 if (trx_hdr.offsets[i] == 0)
 123                         continue;
 124                 part->offset = trx_offset + trx_hdr.offsets[i];
 125                 trx_nr_parts++;
 126         }
 127
 128         for (i = 0; i < trx_nr_parts-1; i++)
 129                 trx_parts[i].size = trx_parts[i+1].offset - trx_parts[i].offset;
 130
 131         trx_parts[i].size = mtd->size - trx_parts[i].offset;
 132
 133         i = 0;
 134         part = &trx_parts[i];
 135         if (part->size < TRX_MIN_KERNEL_SIZE) {
 136                 part->name = "loader";
 137                 i++;
 138         }
 139
 140         part = &trx_parts[i];
 141         part->name = "kernel";
 142         i++;
 143
 144         part = &trx_parts[i];
 145         part->name = "rootfs";
 146
 147         err = add_mtd_partitions(mtd, trx_parts, trx_nr_parts);
 148         if (err) {
 149                 printk(KERN_ALERT PFX "adding TRX partitions failed\n");
 150                 return;
 151         }
 152
 153         mtd->refresh_device = trxsplit_refresh_partitions;
 154 }
 155
 156 static int trxsplit_refresh_partitions(struct mtd_info *mtd)
 157 {
 158         printk(KERN_INFO PFX "refreshing TRX partitions in '%s' (%d,%d)\n",
 159                 mtd->name, MTD_BLOCK_MAJOR, mtd->index);
 160
 161         /* remove old partitions */
 162         del_mtd_partitions(mtd);
 163
 164         trxsplit_findtrx(mtd);
 165         if (!trx_mtd)
 166                 goto err;
 167
 168         trxsplit_create_partitions(trx_mtd);
 169         return 1;
 170
 171 err:
 172         return 0;
 173 }
 174
 175 static void __init trxsplit_add_mtd(struct mtd_info *mtd)
 176 {
 177         if (mtd->type != MTD_NORFLASH) {
 178                 printk(KERN_INFO PFX "'%s' is not a NOR flash, skipped\n",
 179                                 mtd->name);
 180                 return;
 181         }
 182
 183         if (!trx_mtd)
 184                 trxsplit_findtrx(mtd);
 185 }
 186
 187 static void __init trxsplit_remove_mtd(struct mtd_info *mtd)
 188 {
 189         /* nothing to do */
 190 }
 191
 192 static struct mtd_notifier trxsplit_notifier __initdata = {
 193         .add    = trxsplit_add_mtd,
 194         .remove = trxsplit_remove_mtd,
 195 };
 196
 197 static void __init trxsplit_scan(void)
 198 {
 199         register_mtd_user(&trxsplit_notifier);
 200         unregister_mtd_user(&trxsplit_notifier);
 201 }
 202
 203 static int __init trxsplit_init(void)
 204 {
 205         trxsplit_scan();
 206
 207         if (trx_mtd) {
 208                 printk(KERN_INFO PFX "creating TRX partitions in '%s' "
 209                         "(%d,%d)\n", trx_mtd->name, MTD_BLOCK_MAJOR,
 210                         trx_mtd->index);
 211                 trxsplit_create_partitions(trx_mtd);
 212         }
 213
 214         return 0;
 215 }
 216
 217 late_initcall(trxsplit_init);