target/linux/bcm4908/patches-5.10/040-v6.1-mtd-parsers-add-Broadcom-s-U-Boot-parser.patch

   1 From 002181f5b150e60c77f21de7ad4dd10e4614cd91 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
   3 Date: Mon, 11 Jul 2022 17:30:41 +0200
   4 Subject: [PATCH] mtd: parsers: add Broadcom's U-Boot parser
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 Broadcom stores environment variables blocks inside U-Boot partition
  10 itself. This driver finds & registers them.
  11
  12 Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
  13 Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
  14 Link: https://lore.kernel.org/linux-mtd/20220711153041.6036-2-zajec5@gmail.com
  15 ---
  16  drivers/mtd/parsers/Kconfig       | 10 ++++
  17  drivers/mtd/parsers/Makefile      |  1 +
  18  drivers/mtd/parsers/brcm_u-boot.c | 84 +++++++++++++++++++++++++++++++
  19  3 files changed, 95 insertions(+)
  20  create mode 100644 drivers/mtd/parsers/brcm_u-boot.c
  21
  22 --- a/drivers/mtd/parsers/Kconfig
  23 +++ b/drivers/mtd/parsers/Kconfig
  24 @@ -20,6 +20,16 @@ config MTD_BCM63XX_PARTS
  25           This provides partition parsing for BCM63xx devices with CFE
  26           bootloaders.
  27
  28 +config MTD_BRCM_U_BOOT
  29 +       tristate "Broadcom's U-Boot partition parser"
  30 +       depends on ARCH_BCM4908 || COMPILE_TEST
  31 +       help
  32 +         Broadcom uses a custom way of storing U-Boot environment variables.
  33 +         They are placed inside U-Boot partition itself at unspecified offset.
  34 +         It's possible to locate them by looking for a custom header with a
  35 +         magic value. This driver does that and creates subpartitions for
  36 +         each found environment variables block.
  37 +
  38  config MTD_CMDLINE_PARTS
  39         tristate "Command line partition table parsing"
  40         depends on MTD
  41 --- a/drivers/mtd/parsers/Makefile
  42 +++ b/drivers/mtd/parsers/Makefile
  43 @@ -2,6 +2,7 @@
  44  obj-$(CONFIG_MTD_AR7_PARTS)            += ar7part.o
  45  obj-$(CONFIG_MTD_BCM47XX_PARTS)                += bcm47xxpart.o
  46  obj-$(CONFIG_MTD_BCM63XX_PARTS)                += bcm63xxpart.o
  47 +obj-$(CONFIG_MTD_BRCM_U_BOOT)          += brcm_u-boot.o
  48  obj-$(CONFIG_MTD_CMDLINE_PARTS)                += cmdlinepart.o
  49  obj-$(CONFIG_MTD_MYLOADER_PARTS)               += myloader.o
  50  obj-$(CONFIG_MTD_OF_PARTS)             += ofpart.o
  51 --- /dev/null
  52 +++ b/drivers/mtd/parsers/brcm_u-boot.c
  53 @@ -0,0 +1,84 @@
  54 +// SPDX-License-Identifier: GPL-2.0-only
  55 +/*
  56 + * Copyright © 2022 Rafał Miłecki <rafal@milecki.pl>
  57 + */
  58 +
  59 +#include <linux/module.h>
  60 +#include <linux/kernel.h>
  61 +#include <linux/slab.h>
  62 +#include <linux/mtd/mtd.h>
  63 +#include <linux/mtd/partitions.h>
  64 +
  65 +#define BRCM_U_BOOT_MAX_OFFSET         0x200000
  66 +#define BRCM_U_BOOT_STEP               0x1000
  67 +
  68 +#define BRCM_U_BOOT_MAX_PARTS          2
  69 +
  70 +#define BRCM_U_BOOT_MAGIC              0x75456e76      /* uEnv */
  71 +
  72 +struct brcm_u_boot_header {
  73 +       __le32 magic;
  74 +       __le32 length;
  75 +} __packed;
  76 +
  77 +static const char *names[BRCM_U_BOOT_MAX_PARTS] = {
  78 +       "u-boot-env",
  79 +       "u-boot-env-backup",
  80 +};
  81 +
  82 +static int brcm_u_boot_parse(struct mtd_info *mtd,
  83 +                            const struct mtd_partition **pparts,
  84 +                            struct mtd_part_parser_data *data)
  85 +{
  86 +       struct brcm_u_boot_header header;
  87 +       struct mtd_partition *parts;
  88 +       size_t bytes_read;
  89 +       size_t offset;
  90 +       int err;
  91 +       int i = 0;
  92 +
  93 +       parts = kcalloc(BRCM_U_BOOT_MAX_PARTS, sizeof(*parts), GFP_KERNEL);
  94 +       if (!parts)
  95 +               return -ENOMEM;
  96 +
  97 +       for (offset = 0;
  98 +            offset < min_t(size_t, mtd->size, BRCM_U_BOOT_MAX_OFFSET);
  99 +            offset += BRCM_U_BOOT_STEP) {
 100 +               err = mtd_read(mtd, offset, sizeof(header), &bytes_read, (uint8_t *)&header);
 101 +               if (err && !mtd_is_bitflip(err)) {
 102 +                       pr_err("Failed to read from %s at 0x%zx: %d\n", mtd->name, offset, err);
 103 +                       continue;
 104 +               }
 105 +
 106 +               if (le32_to_cpu(header.magic) != BRCM_U_BOOT_MAGIC)
 107 +                       continue;
 108 +
 109 +               parts[i].name = names[i];
 110 +               parts[i].offset = offset;
 111 +               parts[i].size = sizeof(header) + le32_to_cpu(header.length);
 112 +               i++;
 113 +               pr_info("offset:0x%zx magic:0x%08x BINGO\n", offset, header.magic);
 114 +
 115 +               if (i == BRCM_U_BOOT_MAX_PARTS)
 116 +                       break;
 117 +       }
 118 +
 119 +       *pparts = parts;
 120 +
 121 +       return i;
 122 +};
 123 +
 124 +static const struct of_device_id brcm_u_boot_of_match_table[] = {
 125 +       { .compatible = "brcm,u-boot" },
 126 +       {},
 127 +};
 128 +MODULE_DEVICE_TABLE(of, brcm_u_boot_of_match_table);
 129 +
 130 +static struct mtd_part_parser brcm_u_boot_mtd_parser = {
 131 +       .parse_fn = brcm_u_boot_parse,
 132 +       .name = "brcm_u-boot",
 133 +       .of_match_table = brcm_u_boot_of_match_table,
 134 +};
 135 +module_mtd_part_parser(brcm_u_boot_mtd_parser);
 136 +
 137 +MODULE_LICENSE("GPL");