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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright © 2022 Rafał Miłecki <rafal@milecki.pl>4 */5 6#include <linux/module.h>7#include <linux/kernel.h>8#include <linux/slab.h>9#include <linux/mtd/mtd.h>10#include <linux/mtd/partitions.h>11 12#define BRCM_U_BOOT_MAX_OFFSET 0x20000013#define BRCM_U_BOOT_STEP 0x100014 15#define BRCM_U_BOOT_MAX_PARTS 216 17#define BRCM_U_BOOT_MAGIC 0x75456e76 /* uEnv */18 19struct brcm_u_boot_header {20 __le32 magic;21 __le32 length;22} __packed;23 24static const char *names[BRCM_U_BOOT_MAX_PARTS] = {25 "u-boot-env",26 "u-boot-env-backup",27};28 29static int brcm_u_boot_parse(struct mtd_info *mtd,30 const struct mtd_partition **pparts,31 struct mtd_part_parser_data *data)32{33 struct brcm_u_boot_header header;34 struct mtd_partition *parts;35 size_t bytes_read;36 size_t offset;37 int err;38 int i = 0;39 40 parts = kcalloc(BRCM_U_BOOT_MAX_PARTS, sizeof(*parts), GFP_KERNEL);41 if (!parts)42 return -ENOMEM;43 44 for (offset = 0;45 offset < min_t(size_t, mtd->size, BRCM_U_BOOT_MAX_OFFSET);46 offset += BRCM_U_BOOT_STEP) {47 err = mtd_read(mtd, offset, sizeof(header), &bytes_read, (uint8_t *)&header);48 if (err && !mtd_is_bitflip(err)) {49 pr_err("Failed to read from %s at 0x%zx: %d\n", mtd->name, offset, err);50 continue;51 }52 53 if (le32_to_cpu(header.magic) != BRCM_U_BOOT_MAGIC)54 continue;55 56 parts[i].name = names[i];57 parts[i].offset = offset;58 parts[i].size = sizeof(header) + le32_to_cpu(header.length);59 i++;60 pr_info("offset:0x%zx magic:0x%08x BINGO\n", offset, header.magic);61 62 if (i == BRCM_U_BOOT_MAX_PARTS)63 break;64 }65 66 *pparts = parts;67 68 return i;69};70 71static const struct of_device_id brcm_u_boot_of_match_table[] = {72 { .compatible = "brcm,u-boot" },73 {},74};75MODULE_DEVICE_TABLE(of, brcm_u_boot_of_match_table);76 77static struct mtd_part_parser brcm_u_boot_mtd_parser = {78 .parse_fn = brcm_u_boot_parse,79 .name = "brcm_u-boot",80 .of_match_table = brcm_u_boot_of_match_table,81};82module_mtd_part_parser(brcm_u_boot_mtd_parser);83 84MODULE_DESCRIPTION("Broadcom's U-Boot partition parser");85MODULE_LICENSE("GPL");86