Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
mtd: parsers: add Broadcom's U-Boot parser
Broadcom stores environment variables blocks inside U-Boot partition
itself. This driver finds & registers them.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220711153041.6036-2-zajec5@gmail.com
authored by
Rafał Miłecki
and committed by
Miquel Raynal
002181f5
27bfb201
+95
+10
drivers/mtd/parsers/Kconfig
+10
drivers/mtd/parsers/Kconfig
···
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This provides partition parsing for BCM63xx devices with CFE
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bootloaders.
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config MTD_BRCM_U_BOOT
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tristate "Broadcom's U-Boot partition parser"
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depends on ARCH_BCM4908 || COMPILE_TEST
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help
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Broadcom uses a custom way of storing U-Boot environment variables.
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They are placed inside U-Boot partition itself at unspecified offset.
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It's possible to locate them by looking for a custom header with a
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magic value. This driver does that and creates subpartitions for
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each found environment variables block.
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config MTD_CMDLINE_PARTS
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tristate "Command line partition table parsing"
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depends on MTD
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drivers/mtd/parsers/Makefile
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drivers/mtd/parsers/Makefile
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obj-$(CONFIG_MTD_AR7_PARTS) += ar7part.o
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obj-$(CONFIG_MTD_BCM47XX_PARTS) += bcm47xxpart.o
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obj-$(CONFIG_MTD_BCM63XX_PARTS) += bcm63xxpart.o
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obj-$(CONFIG_MTD_BRCM_U_BOOT) += brcm_u-boot.o
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obj-$(CONFIG_MTD_CMDLINE_PARTS) += cmdlinepart.o
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obj-$(CONFIG_MTD_OF_PARTS) += ofpart.o
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ofpart-y += ofpart_core.o
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drivers/mtd/parsers/brcm_u-boot.c
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drivers/mtd/parsers/brcm_u-boot.c
···
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright © 2022 Rafał Miłecki <rafal@milecki.pl>
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/mtd/mtd.h>
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#include <linux/mtd/partitions.h>
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#define BRCM_U_BOOT_MAX_OFFSET 0x200000
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#define BRCM_U_BOOT_STEP 0x1000
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#define BRCM_U_BOOT_MAX_PARTS 2
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#define BRCM_U_BOOT_MAGIC 0x75456e76 /* uEnv */
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struct brcm_u_boot_header {
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__le32 magic;
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__le32 length;
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} __packed;
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static const char *names[BRCM_U_BOOT_MAX_PARTS] = {
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"u-boot-env",
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"u-boot-env-backup",
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};
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static int brcm_u_boot_parse(struct mtd_info *mtd,
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const struct mtd_partition **pparts,
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struct mtd_part_parser_data *data)
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{
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struct brcm_u_boot_header header;
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struct mtd_partition *parts;
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size_t bytes_read;
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size_t offset;
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int err;
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int i = 0;
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parts = kcalloc(BRCM_U_BOOT_MAX_PARTS, sizeof(*parts), GFP_KERNEL);
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if (!parts)
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return -ENOMEM;
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for (offset = 0;
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offset < min_t(size_t, mtd->size, BRCM_U_BOOT_MAX_OFFSET);
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offset += BRCM_U_BOOT_STEP) {
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err = mtd_read(mtd, offset, sizeof(header), &bytes_read, (uint8_t *)&header);
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if (err && !mtd_is_bitflip(err)) {
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pr_err("Failed to read from %s at 0x%zx: %d\n", mtd->name, offset, err);
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continue;
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}
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if (le32_to_cpu(header.magic) != BRCM_U_BOOT_MAGIC)
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continue;
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parts[i].name = names[i];
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parts[i].offset = offset;
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parts[i].size = sizeof(header) + le32_to_cpu(header.length);
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i++;
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pr_info("offset:0x%zx magic:0x%08x BINGO\n", offset, header.magic);
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if (i == BRCM_U_BOOT_MAX_PARTS)
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break;
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}
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*pparts = parts;
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return i;
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};
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static const struct of_device_id brcm_u_boot_of_match_table[] = {
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{ .compatible = "brcm,u-boot" },
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{},
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};
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MODULE_DEVICE_TABLE(of, brcm_u_boot_of_match_table);
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static struct mtd_part_parser brcm_u_boot_mtd_parser = {
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.parse_fn = brcm_u_boot_parse,
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.name = "brcm_u-boot",
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.of_match_table = brcm_u_boot_of_match_table,
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};
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module_mtd_part_parser(brcm_u_boot_mtd_parser);
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MODULE_LICENSE("GPL");