target/linux/generic/files/drivers/mtd/myloader.c

   1 /*
   2  *  Parse MyLoader-style flash partition tables and produce a Linux partition
   3  *  array to match.
   4  *
   5  *  Copyright (C) 2007-2009 Gabor Juhos <juhosg@openwrt.org>
   6  *
   7  *  This file was based on drivers/mtd/redboot.c
   8  *  Author: Red Hat, Inc. - David Woodhouse <dwmw2@cambridge.redhat.com>
   9  *
  10  *  This program is free software; you can redistribute it and/or modify it
  11  *  under the terms of the GNU General Public License version 2 as published
  12  *  by the Free Software Foundation.
  13  *
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/version.h>
  19 #include <linux/slab.h>
  20 #include <linux/init.h>
  21 #include <linux/vmalloc.h>
  22 #include <linux/mtd/mtd.h>
  23 #include <linux/mtd/partitions.h>
  24 #include <linux/byteorder/generic.h>
  25 #include <linux/myloader.h>
  26
  27 #define BLOCK_LEN_MIN           0x10000
  28 #define PART_NAME_LEN           32
  29
  30 struct part_data {
  31         struct mylo_partition_table     tab;
  32         char names[MYLO_MAX_PARTITIONS][PART_NAME_LEN];
  33 };
  34
  35 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,2,0))
  36 static int myloader_parse_partitions(struct mtd_info *master,
  37                                      struct mtd_partition **pparts,
  38                                      struct mtd_part_parser_data *data)
  39 #else
  40 static int myloader_parse_partitions(struct mtd_info *master,
  41                                      struct mtd_partition **pparts,
  42                                      unsigned long origin)
  43 #endif
  44 {
  45         struct part_data *buf;
  46         struct mylo_partition_table *tab;
  47         struct mylo_partition *part;
  48         struct mtd_partition *mtd_parts;
  49         struct mtd_partition *mtd_part;
  50         int num_parts;
  51         int ret, i;
  52         size_t retlen;
  53         char *names;
  54         unsigned long offset;
  55         unsigned long blocklen;
  56
  57         buf = vmalloc(sizeof(*buf));
  58         if (!buf) {
  59                 return -ENOMEM;
  60                 goto out;
  61         }
  62         tab = &buf->tab;
  63
  64         blocklen = master->erasesize;
  65         if (blocklen < BLOCK_LEN_MIN)
  66                 blocklen = BLOCK_LEN_MIN;
  67
  68         offset = blocklen;
  69
  70         /* Find the partition table */
  71         for (i = 0; i < 4; i++, offset += blocklen) {
  72                 printk(KERN_DEBUG "%s: searching for MyLoader partition table"
  73                                 " at offset 0x%lx\n", master->name, offset);
  74
  75                 ret = master->read(master, offset, sizeof(*buf), &retlen,
  76                                         (void *)buf);
  77                 if (ret)
  78                         goto out_free_buf;
  79
  80                 if (retlen != sizeof(*buf)) {
  81                         ret = -EIO;
  82                         goto out_free_buf;
  83                 }
  84
  85                 /* Check for Partition Table magic number */
  86                 if (tab->magic == le32_to_cpu(MYLO_MAGIC_PARTITIONS))
  87                         break;
  88
  89         }
  90
  91         if (tab->magic != le32_to_cpu(MYLO_MAGIC_PARTITIONS)) {
  92                 printk(KERN_DEBUG "%s: no MyLoader partition table found\n",
  93                         master->name);
  94                 ret = 0;
  95                 goto out_free_buf;
  96         }
  97
  98         /* The MyLoader and the Partition Table is always present */
  99         num_parts = 2;
 100
 101         /* Detect number of used partitions */
 102         for (i = 0; i < MYLO_MAX_PARTITIONS; i++) {
 103                 part = &tab->partitions[i];
 104
 105                 if (le16_to_cpu(part->type) == PARTITION_TYPE_FREE)
 106                         continue;
 107
 108                 num_parts++;
 109         }
 110
 111         mtd_parts = kzalloc((num_parts * sizeof(*mtd_part) +
 112                                 num_parts * PART_NAME_LEN), GFP_KERNEL);
 113
 114         if (!mtd_parts) {
 115                 ret = -ENOMEM;
 116                 goto out_free_buf;
 117         }
 118
 119         mtd_part = mtd_parts;
 120         names = (char *)&mtd_parts[num_parts];
 121
 122         strncpy(names, "myloader", PART_NAME_LEN);
 123         mtd_part->name = names;
 124         mtd_part->offset = 0;
 125         mtd_part->size = offset;
 126         mtd_part->mask_flags = MTD_WRITEABLE;
 127         mtd_part++;
 128         names += PART_NAME_LEN;
 129
 130         strncpy(names, "partition_table", PART_NAME_LEN);
 131         mtd_part->name = names;
 132         mtd_part->offset = offset;
 133         mtd_part->size = blocklen;
 134         mtd_part->mask_flags = MTD_WRITEABLE;
 135         mtd_part++;
 136         names += PART_NAME_LEN;
 137
 138         for (i = 0; i < MYLO_MAX_PARTITIONS; i++) {
 139                 part = &tab->partitions[i];
 140
 141                 if (le16_to_cpu(part->type) == PARTITION_TYPE_FREE)
 142                         continue;
 143
 144                 if ((buf->names[i][0]) && (buf->names[i][0] != '\xff'))
 145                         strncpy(names, buf->names[i], PART_NAME_LEN);
 146                 else
 147                         snprintf(names, PART_NAME_LEN, "partition%d", i);
 148
 149                 mtd_part->offset = le32_to_cpu(part->addr);
 150                 mtd_part->size = le32_to_cpu(part->size);
 151                 mtd_part->name = names;
 152                 mtd_part++;
 153                 names += PART_NAME_LEN;
 154         }
 155
 156         *pparts = mtd_parts;
 157         ret = num_parts;
 158
 159  out_free_buf:
 160         vfree(buf);
 161  out:
 162         return ret;
 163 }
 164
 165 static struct mtd_part_parser myloader_mtd_parser = {
 166         .owner          = THIS_MODULE,
 167         .parse_fn       = myloader_parse_partitions,
 168         .name           = "MyLoader",
 169 };
 170
 171 static int __init myloader_mtd_parser_init(void)
 172 {
 173         return register_mtd_parser(&myloader_mtd_parser);
 174 }
 175
 176 static void __exit myloader_mtd_parser_exit(void)
 177 {
 178         deregister_mtd_parser(&myloader_mtd_parser);
 179 }
 180
 181 module_init(myloader_mtd_parser_init);
 182 module_exit(myloader_mtd_parser_exit);
 183
 184 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 185 MODULE_DESCRIPTION("Parsing code for MyLoader partition tables");
 186 MODULE_LICENSE("GPL v2");