target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_cfe_bootfs.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2021 Rafał Miłecki <rafal@milecki.pl>
   4  */
   5
   6 #include <linux/init.h>
   7 #include <linux/jffs2.h>
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/mtd/mtd.h>
  11 #include <linux/mtd/partitions.h>
  12 #include <linux/of.h>
  13 #include <linux/slab.h>
  14
  15 #include "mtdsplit.h"
  16
  17 #define je16_to_cpu(x) ((x).v16)
  18 #define je32_to_cpu(x) ((x).v32)
  19
  20 #define NR_PARTS                2
  21
  22 static int mtdsplit_cfe_bootfs_parse(struct mtd_info *mtd,
  23                                      const struct mtd_partition **pparts,
  24                                      struct mtd_part_parser_data *data)
  25 {
  26         struct jffs2_raw_dirent node;
  27         enum mtdsplit_part_type type;
  28         struct mtd_partition *parts;
  29         size_t rootfs_offset;
  30         size_t retlen;
  31         size_t offset;
  32         int err;
  33
  34         /* Don't parse backup partitions */
  35         if (strcmp(mtd->name, "firmware"))
  36                 return -EINVAL;
  37
  38         /* Find the end of JFFS2 bootfs partition */
  39         offset = 0;
  40         do {
  41                 err = mtd_read(mtd, offset, sizeof(node), &retlen, (void *)&node);
  42                 if (err || retlen != sizeof(node))
  43                         break;
  44
  45                 if (je16_to_cpu(node.magic) != JFFS2_MAGIC_BITMASK)
  46                         break;
  47
  48                 offset += je32_to_cpu(node.totlen);
  49                 offset = (offset + 0x3) & ~0x3;
  50         } while (offset < mtd->size);
  51
  52         /* Find rootfs partition that follows the bootfs */
  53         err = mtd_find_rootfs_from(mtd, mtd->erasesize, mtd->size, &rootfs_offset, &type);
  54         if (err)
  55                 return err;
  56
  57         parts = kzalloc(NR_PARTS * sizeof(*parts), GFP_KERNEL);
  58         if (!parts)
  59                 return -ENOMEM;
  60
  61         parts[0].name = "bootfs";
  62         parts[0].offset = 0;
  63         parts[0].size = rootfs_offset;
  64
  65         if (type == MTDSPLIT_PART_TYPE_UBI)
  66                 parts[1].name = UBI_PART_NAME;
  67         else
  68                 parts[1].name = ROOTFS_PART_NAME;
  69         parts[1].offset = rootfs_offset;
  70         parts[1].size = mtd->size - rootfs_offset;
  71
  72         *pparts = parts;
  73
  74         return NR_PARTS;
  75 }
  76
  77 static const struct of_device_id mtdsplit_cfe_bootfs_of_match_table[] = {
  78         { .compatible = "brcm,bcm4908-firmware" },
  79         {},
  80 };
  81 MODULE_DEVICE_TABLE(of, mtdsplit_cfe_bootfs_of_match_table);
  82
  83 static struct mtd_part_parser mtdsplit_cfe_bootfs_parser = {
  84         .owner = THIS_MODULE,
  85         .name = "cfe-bootfs",
  86         .of_match_table = mtdsplit_cfe_bootfs_of_match_table,
  87         .parse_fn = mtdsplit_cfe_bootfs_parse,
  88 };
  89
  90 module_mtd_part_parser(mtdsplit_cfe_bootfs_parser);