// SPDX-License-Identifier: GPL-2.0-only /* * Copyright © 2022 Rafał Miłecki <rafal@milecki.pl> */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/slab.h> #include <linux/mtd/mtd.h> #include <linux/mtd/partitions.h> #define BRCM_U_BOOT_MAX_OFFSET 0x200000 #define BRCM_U_BOOT_STEP 0x1000 #define BRCM_U_BOOT_MAX_PARTS 2 #define BRCM_U_BOOT_MAGIC 0x75456e76 /* uEnv */ struct brcm_u_boot_header { __le32 magic; __le32 length; } __packed; static const char *names[BRCM_U_BOOT_MAX_PARTS] = { "u-boot-env", "u-boot-env-backup", }; static int brcm_u_boot_parse(struct mtd_info *mtd, const struct mtd_partition **pparts, struct mtd_part_parser_data *data) { struct brcm_u_boot_header header; struct mtd_partition *parts; size_t bytes_read; size_t offset; int err; int i = 0; parts = kcalloc(BRCM_U_BOOT_MAX_PARTS, sizeof(*parts), GFP_KERNEL); if (!parts) return -ENOMEM; for (offset = 0; offset < min_t(size_t, mtd->size, BRCM_U_BOOT_MAX_OFFSET); offset += BRCM_U_BOOT_STEP) { err = mtd_read(mtd, offset, sizeof(header), &bytes_read, (uint8_t *)&header); if (err && !mtd_is_bitflip(err)) { pr_err("Failed to read from %s at 0x%zx: %d\n", mtd->name, offset, err); continue; } if (le32_to_cpu(header.magic) != BRCM_U_BOOT_MAGIC) continue; parts[i].name = names[i]; parts[i].offset = offset; parts[i].size = sizeof(header) + le32_to_cpu(header.length); i++; pr_info("offset:0x%zx magic:0x%08x BINGO\n", offset, header.magic); if (i == BRCM_U_BOOT_MAX_PARTS) break; } *pparts = parts; return i; }; static const struct of_device_id brcm_u_boot_of_match_table[] = { { .compatible = "brcm,u-boot" }, {}, }; MODULE_DEVICE_TABLE(of, brcm_u_boot_of_match_table); static struct mtd_part_parser brcm_u_boot_mtd_parser = { .parse_fn = brcm_u_boot_parse, .name = "brcm_u-boot", .of_match_table = brcm_u_boot_of_match_table, }; module_mtd_part_parser(brcm_u_boot_mtd_parser); MODULE_DESCRIPTION("Broadcom's U-Boot partition parser"); MODULE_LICENSE("GPL");