137149847d
Broadcom's U-Boot contains environment data blocks. They need to be found (offsets aren't predefined) to access env variables. Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
138 lines
4.1 KiB
Diff
138 lines
4.1 KiB
Diff
From 002181f5b150e60c77f21de7ad4dd10e4614cd91 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
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Date: Mon, 11 Jul 2022 17:30:41 +0200
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Subject: [PATCH] mtd: parsers: add Broadcom's U-Boot parser
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Broadcom stores environment variables blocks inside U-Boot partition
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itself. This driver finds & registers them.
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Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
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Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
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Link: https://lore.kernel.org/linux-mtd/20220711153041.6036-2-zajec5@gmail.com
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---
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drivers/mtd/parsers/Kconfig | 10 ++++
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drivers/mtd/parsers/Makefile | 1 +
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drivers/mtd/parsers/brcm_u-boot.c | 84 +++++++++++++++++++++++++++++++
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3 files changed, 95 insertions(+)
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create mode 100644 drivers/mtd/parsers/brcm_u-boot.c
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--- a/drivers/mtd/parsers/Kconfig
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+++ b/drivers/mtd/parsers/Kconfig
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@@ -20,6 +20,16 @@ config MTD_BCM63XX_PARTS
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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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+
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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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--- a/drivers/mtd/parsers/Makefile
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+++ b/drivers/mtd/parsers/Makefile
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@@ -2,6 +2,7 @@
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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_MYLOADER_PARTS) += myloader.o
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obj-$(CONFIG_MTD_OF_PARTS) += ofpart.o
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--- /dev/null
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+++ b/drivers/mtd/parsers/brcm_u-boot.c
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@@ -0,0 +1,84 @@
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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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+
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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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+
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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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+
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+#define BRCM_U_BOOT_MAX_PARTS 2
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+
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+#define BRCM_U_BOOT_MAGIC 0x75456e76 /* uEnv */
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+
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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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+
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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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+
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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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+
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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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+
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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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+
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+ if (le32_to_cpu(header.magic) != BRCM_U_BOOT_MAGIC)
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+ continue;
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+
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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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+
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+ if (i == BRCM_U_BOOT_MAX_PARTS)
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+ break;
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+ }
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+
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+ *pparts = parts;
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+
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+ return i;
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+};
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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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+
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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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+
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+MODULE_LICENSE("GPL");
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