1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 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 0x200000 13 #define BRCM_U_BOOT_STEP 0x1000 14 15 #define BRCM_U_BOOT_MAX_PARTS 2 16 17 #define BRCM_U_BOOT_MAGIC 0x75456e76 /* uEnv */ 18 19 struct brcm_u_boot_header { 20 __le32 magic; 21 __le32 length; 22 } __packed; 23 24 static const char *names[BRCM_U_BOOT_MAX_PARTS] = { 25 "u-boot-env", 26 "u-boot-env-backup", 27 }; 28 29 static 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 71 static const struct of_device_id brcm_u_boot_of_match_table[] = { 72 { .compatible = "brcm,u-boot" }, 73 {}, 74 }; 75 MODULE_DEVICE_TABLE(of, brcm_u_boot_of_match_table); 76 77 static 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 }; 82 module_mtd_part_parser(brcm_u_boot_mtd_parser); 83 84 MODULE_LICENSE("GPL"); 85