bcm4908: backport mtd parser for Broadcom's U-Boot partition

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>
(cherry picked from commit 137149847d0f374515f38952ce0986b03a97f2e4)

diff --git a/target/linux/bcm4908/config-5.4 b/target/linux/bcm4908/config-5.4
index a11cfc84ac98d9f1477c7d9f39e786412b525a56..e051e900dfb92da3c902824c9ebfebaa3ba30186 100644 (file)
--- a/target/linux/bcm4908/config-5.4
+++ b/target/linux/bcm4908/config-5.4
@@ -142,6 +142,7 @@ CONFIG_MEMFD_CREATE=y
 CONFIG_MFD_SYSCON=y
 CONFIG_MIGRATION=y
 CONFIG_MODULES_USE_ELF_RELA=y
+CONFIG_MTD_BRCM_U_BOOT=y
 CONFIG_MTD_CMDLINE_PARTS=y
 CONFIG_MTD_NAND_BRCMNAND=y
 CONFIG_MTD_NAND_CORE=y

diff --git a/target/linux/bcm4908/patches-5.4/040-v6.1-mtd-parsers-add-Broadcom-s-U-Boot-parser.patch b/target/linux/bcm4908/patches-5.4/040-v6.1-mtd-parsers-add-Broadcom-s-U-Boot-parser.patch
new file mode 100644 (file)
index 0000000..4d4059b
--- /dev/null
+++ b/target/linux/bcm4908/patches-5.4/040-v6.1-mtd-parsers-add-Broadcom-s-U-Boot-parser.patch
@@ -0,0 +1,137 @@
+From 002181f5b150e60c77f21de7ad4dd10e4614cd91 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Mon, 11 Jul 2022 17:30:41 +0200
+Subject: [PATCH] mtd: parsers: add Broadcom's U-Boot parser
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+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
+---
+ drivers/mtd/parsers/Kconfig       | 10 ++++
+ drivers/mtd/parsers/Makefile      |  1 +
+ drivers/mtd/parsers/brcm_u-boot.c | 84 +++++++++++++++++++++++++++++++
+ 3 files changed, 95 insertions(+)
+ create mode 100644 drivers/mtd/parsers/brcm_u-boot.c
+
+--- a/drivers/mtd/parsers/Kconfig
++++ b/drivers/mtd/parsers/Kconfig
+@@ -20,6 +20,16 @@ config MTD_BCM63XX_PARTS
+         This provides partition parsing for BCM63xx devices with CFE
+         bootloaders.
+ 
++config MTD_BRCM_U_BOOT
++      tristate "Broadcom's U-Boot partition parser"
++      depends on ARCH_BCM4908 || COMPILE_TEST
++      help
++        Broadcom uses a custom way of storing U-Boot environment variables.
++        They are placed inside U-Boot partition itself at unspecified offset.
++        It's possible to locate them by looking for a custom header with a
++        magic value. This driver does that and creates subpartitions for
++        each found environment variables block.
++
+ config MTD_CMDLINE_PARTS
+       tristate "Command line partition table parsing"
+       depends on MTD
+--- a/drivers/mtd/parsers/Makefile
++++ b/drivers/mtd/parsers/Makefile
+@@ -2,6 +2,7 @@
+ obj-$(CONFIG_MTD_AR7_PARTS)           += ar7part.o
+ obj-$(CONFIG_MTD_BCM47XX_PARTS)               += bcm47xxpart.o
+ obj-$(CONFIG_MTD_BCM63XX_PARTS)               += bcm63xxpart.o
++obj-$(CONFIG_MTD_BRCM_U_BOOT)         += brcm_u-boot.o
+ obj-$(CONFIG_MTD_CMDLINE_PARTS)               += cmdlinepart.o
+ obj-$(CONFIG_MTD_MYLOADER_PARTS)              += myloader.o
+ obj-$(CONFIG_MTD_OF_PARTS)            += ofpart.o
+--- /dev/null
++++ b/drivers/mtd/parsers/brcm_u-boot.c
+@@ -0,0 +1,84 @@
++// SPDX-License-Identifier: GPL-2.0-only
++/*
++ * Copyright © 2022 Rafał Miłecki <rafal@milecki.pl>
++ */
++
++#include <linux/module.h>
++#include <linux/kernel.h>
++#include <linux/slab.h>
++#include <linux/mtd/mtd.h>
++#include <linux/mtd/partitions.h>
++
++#define BRCM_U_BOOT_MAX_OFFSET                0x200000
++#define BRCM_U_BOOT_STEP              0x1000
++
++#define BRCM_U_BOOT_MAX_PARTS         2
++
++#define BRCM_U_BOOT_MAGIC             0x75456e76      /* uEnv */
++
++struct brcm_u_boot_header {
++      __le32 magic;
++      __le32 length;
++} __packed;
++
++static const char *names[BRCM_U_BOOT_MAX_PARTS] = {
++      "u-boot-env",
++      "u-boot-env-backup",
++};
++
++static int brcm_u_boot_parse(struct mtd_info *mtd,
++                           const struct mtd_partition **pparts,
++                           struct mtd_part_parser_data *data)
++{
++      struct brcm_u_boot_header header;
++      struct mtd_partition *parts;
++      size_t bytes_read;
++      size_t offset;
++      int err;
++      int i = 0;
++
++      parts = kcalloc(BRCM_U_BOOT_MAX_PARTS, sizeof(*parts), GFP_KERNEL);
++      if (!parts)
++              return -ENOMEM;
++
++      for (offset = 0;
++           offset < min_t(size_t, mtd->size, BRCM_U_BOOT_MAX_OFFSET);
++           offset += BRCM_U_BOOT_STEP) {
++              err = mtd_read(mtd, offset, sizeof(header), &bytes_read, (uint8_t *)&header);
++              if (err && !mtd_is_bitflip(err)) {
++                      pr_err("Failed to read from %s at 0x%zx: %d\n", mtd->name, offset, err);
++                      continue;
++              }
++
++              if (le32_to_cpu(header.magic) != BRCM_U_BOOT_MAGIC)
++                      continue;
++
++              parts[i].name = names[i];
++              parts[i].offset = offset;
++              parts[i].size = sizeof(header) + le32_to_cpu(header.length);
++              i++;
++              pr_info("offset:0x%zx magic:0x%08x BINGO\n", offset, header.magic);
++
++              if (i == BRCM_U_BOOT_MAX_PARTS)
++                      break;
++      }
++
++      *pparts = parts;
++
++      return i;
++};
++
++static const struct of_device_id brcm_u_boot_of_match_table[] = {
++      { .compatible = "brcm,u-boot" },
++      {},
++};
++MODULE_DEVICE_TABLE(of, brcm_u_boot_of_match_table);
++
++static struct mtd_part_parser brcm_u_boot_mtd_parser = {
++      .parse_fn = brcm_u_boot_parse,
++      .name = "brcm_u-boot",
++      .of_match_table = brcm_u_boot_of_match_table,
++};
++module_mtd_part_parser(brcm_u_boot_mtd_parser);
++
++MODULE_LICENSE("GPL");