drivers/mtd/redboot.c

   1 /*
   2  * $Id: redboot.c,v 1.13 2004/04/01 10:17:40 gthomas Exp $
   3  *
   4  * Parse RedBoot-style Flash Image System (FIS) tables and
   5  * produce a Linux partition array to match.
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/slab.h>
  10 #include <linux/init.h>
  11
  12 #include <linux/mtd/mtd.h>
  13 #include <linux/mtd/partitions.h>
  14
  15 struct fis_image_desc {
  16     unsigned char name[16];      // Null terminated name
  17     unsigned long flash_base;    // Address within FLASH of image
  18     unsigned long mem_base;      // Address in memory where it executes
  19     unsigned long size;          // Length of image
  20     unsigned long entry_point;   // Execution entry point
  21     unsigned long data_length;   // Length of actual data
  22     unsigned char _pad[256-(16+7*sizeof(unsigned long))];
  23     unsigned long desc_cksum;    // Checksum over image descriptor
  24     unsigned long file_cksum;    // Checksum over image data
  25 };
  26
  27 struct fis_list {
  28         struct fis_image_desc *img;
  29         struct fis_list *next;
  30 };
  31
  32 static inline int redboot_checksum(struct fis_image_desc *img)
  33 {
  34         /* RedBoot doesn't actually write the desc_cksum field yet AFAICT */
  35         return 1;
  36 }
  37
  38 static int parse_redboot_partitions(struct mtd_info *master,
  39                              struct mtd_partition **pparts,
  40                              unsigned long fis_origin)
  41 {
  42         int nrparts = 0;
  43         struct fis_image_desc *buf;
  44         struct mtd_partition *parts;
  45         struct fis_list *fl = NULL, *tmp_fl;
  46         int ret, i;
  47         size_t retlen;
  48         char *names;
  49         char *nullname;
  50         int namelen = 0;
  51         int nulllen = 0;
  52 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
  53         static char nullstring[] = "unallocated";
  54 #endif
  55
  56         buf = kmalloc(master->erasesize, GFP_KERNEL);
  57
  58         if (!buf)
  59                 return -ENOMEM;
  60
  61         /* Read the start of the last erase block */
  62         ret = master->read(master, master->size - master->erasesize,
  63                            master->erasesize, &retlen, (void *)buf);
  64
  65         if (ret)
  66                 goto out;
  67
  68         if (retlen != master->erasesize) {
  69                 ret = -EIO;
  70                 goto out;
  71         }
  72
  73         /* RedBoot image could appear in any of the first three slots */
  74         for (i = 0; i < 3; i++) {
  75                 if (!memcmp(buf[i].name, "RedBoot", 8))
  76                         break;
  77         }
  78         if (i == 3) {
  79                 /* Didn't find it */
  80                 printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
  81                        master->name);
  82                 ret = 0;
  83                 goto out;
  84         }
  85
  86         for (i = 0; i < master->erasesize / sizeof(struct fis_image_desc); i++) {
  87                 struct fis_list *new_fl, **prev;
  88
  89                 if (buf[i].name[0] == 0xff)
  90                         break;
  91                 if (!redboot_checksum(&buf[i]))
  92                         break;
  93
  94                 new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
  95                 namelen += strlen(buf[i].name)+1;
  96                 if (!new_fl) {
  97                         ret = -ENOMEM;
  98                         goto out;
  99                 }
 100                 new_fl->img = &buf[i];
 101                 if (fis_origin) {
 102                         buf[i].flash_base -= fis_origin;
 103                 } else {
 104                         buf[i].flash_base &= master->size-1;
 105                 }
 106
 107                 /* I'm sure the JFFS2 code has done me permanent damage.
 108                  * I now think the following is _normal_
 109                  */
 110                 prev = &fl;
 111                 while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
 112                         prev = &(*prev)->next;
 113                 new_fl->next = *prev;
 114                 *prev = new_fl;
 115
 116                 nrparts++;
 117         }
 118 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 119         if (fl->img->flash_base) {
 120                 nrparts++;
 121                 nulllen = sizeof(nullstring);
 122         }
 123
 124         for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
 125                 if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) {
 126                         nrparts++;
 127                         nulllen = sizeof(nullstring);
 128                 }
 129         }
 130 #endif
 131         parts = kmalloc(sizeof(*parts)*nrparts + nulllen + namelen, GFP_KERNEL);
 132
 133         if (!parts) {
 134                 ret = -ENOMEM;
 135                 goto out;
 136         }
 137
 138         memset(parts, 0, sizeof(*parts)*nrparts + nulllen + namelen);
 139
 140         nullname = (char *)&parts[nrparts];
 141 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 142         if (nulllen > 0) {
 143                 strcpy(nullname, nullstring);
 144         }
 145 #endif
 146         names = nullname + nulllen;
 147
 148         i=0;
 149
 150 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 151         if (fl->img->flash_base) {
 152                parts[0].name = nullname;
 153                parts[0].size = fl->img->flash_base;
 154                parts[0].offset = 0;
 155                 i++;
 156         }
 157 #endif
 158         for ( ; i<nrparts; i++) {
 159                 parts[i].size = fl->img->size;
 160                 parts[i].offset = fl->img->flash_base;
 161                 parts[i].name = names;
 162
 163                 strcpy(names, fl->img->name);
 164 #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
 165                 if (!memcmp(names, "RedBoot", 8) ||
 166                                 !memcmp(names, "RedBoot config", 15) ||
 167                                 !memcmp(names, "FIS directory", 14)) {
 168                         parts[i].mask_flags = MTD_WRITEABLE;
 169                 }
 170 #endif
 171                 names += strlen(names)+1;
 172
 173 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 174                 if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) {
 175                         i++;
 176                         parts[i].offset = parts[i-1].size + parts[i-1].offset;
 177                         parts[i].size = fl->next->img->flash_base - parts[i].offset;
 178                         parts[i].name = nullname;
 179                 }
 180 #endif
 181                 tmp_fl = fl;
 182                 fl = fl->next;
 183                 kfree(tmp_fl);
 184         }
 185         ret = nrparts;
 186         *pparts = parts;
 187  out:
 188         while (fl) {
 189                 struct fis_list *old = fl;
 190                 fl = fl->next;
 191                 kfree(old);
 192         }
 193         kfree(buf);
 194         return ret;
 195 }
 196
 197 static struct mtd_part_parser redboot_parser = {
 198         .owner = THIS_MODULE,
 199         .parse_fn = parse_redboot_partitions,
 200         .name = "RedBoot",
 201 };
 202
 203 static int __init redboot_parser_init(void)
 204 {
 205         return register_mtd_parser(&redboot_parser);
 206 }
 207
 208 static void __exit redboot_parser_exit(void)
 209 {
 210         deregister_mtd_parser(&redboot_parser);
 211 }
 212
 213 module_init(redboot_parser_init);
 214 module_exit(redboot_parser_exit);
 215
 216 MODULE_LICENSE("GPL");
 217 MODULE_AUTHOR("Red Hat, Inc. - David Woodhouse <dwmw2@cambridge.redhat.com>");
 218 MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");