kernel: add parser finding rootfs after CFE bootfs

It's required for BCM4908. It cannot use "bcm-wfi-fw" parser because
that one requires *two* JFFS2 partitions which is untested / unsupported
on the BCM4908 architecture. With a single JFFS2 partition "bcm-wfi-fw"
parser will:
1. Fail to find "vmlinux.lz" as it doesn't follow "1-openwrt" file
2. Create partitions that don't precisely match bootfs layout

The new parser is described in details in the MTD_SPLIT_CFE_BOOTFS
symbol help message.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

diff --git a/target/linux/bcm4908/config-5.4 b/target/linux/bcm4908/config-5.4
index 3dfa7b21dcceff1bb85211c12b93595f169b5499..d13753c49d76d8143e0f38e7dc936f469cc9ce1d 100644 (file)
--- a/target/linux/bcm4908/config-5.4
+++ b/target/linux/bcm4908/config-5.4
@@ -138,7 +138,8 @@ CONFIG_MTD_NAND_BRCMNAND=y
 CONFIG_MTD_NAND_CORE=y
 CONFIG_MTD_NAND_ECC_SW_HAMMING=y
 CONFIG_MTD_RAW_NAND=y
-CONFIG_MTD_SPLIT_BCM_WFI_FW=y
+CONFIG_MTD_SPLIT_CFE_BOOTFS=y
+# CONFIG_MTD_SPLIT_SQUASHFS_ROOT is not set
 CONFIG_MTD_UBI=y
 CONFIG_MTD_UBI_BEB_LIMIT=20
 CONFIG_MTD_UBI_BLOCK=y

diff --git a/target/linux/generic/files/drivers/mtd/mtdsplit/Kconfig b/target/linux/generic/files/drivers/mtd/mtdsplit/Kconfig
index 3b7e23af33a86c0a0f515e73091acbd5a856bb02..4832b8d9e45e3c81d4d5ad293189ae8b714fe010 100644 (file)
--- a/target/linux/generic/files/drivers/mtd/mtdsplit/Kconfig
+++ b/target/linux/generic/files/drivers/mtd/mtdsplit/Kconfig
@@ -25,6 +25,18 @@ config MTD_SPLIT_BCM_WFI_FW
        depends on MTD_SPLIT_SUPPORT
        select MTD_SPLIT
 
+config MTD_SPLIT_CFE_BOOTFS
+       bool "Parser finding rootfs appended to the CFE bootfs"
+       depends on MTD_SPLIT_SUPPORT && ARCH_BCM4908
+       select MTD_SPLIT
+       help
+         cferom on BCM4908 (and bcm63xx) uses JFFS2 bootfs partition
+         for storing kernel, cferam and some device specific files.
+         There isn't any straight way of storing rootfs so it gets
+         appended to the JFFS2 bootfs partition. Kernel needs to find
+         it and run init from it. This parser is responsible for
+         finding appended rootfs.
+
 config MTD_SPLIT_SEAMA_FW
        bool "Seama firmware parser"
        depends on MTD_SPLIT_SUPPORT

diff --git a/target/linux/generic/files/drivers/mtd/mtdsplit/Makefile b/target/linux/generic/files/drivers/mtd/mtdsplit/Makefile
index 8671628e7cd92741aa69178cbcd4135b05b12eb9..9217d8f64fbb9059628ce4eed98b57e8da70088c 100644 (file)
--- a/target/linux/generic/files/drivers/mtd/mtdsplit/Makefile
+++ b/target/linux/generic/files/drivers/mtd/mtdsplit/Makefile
@@ -1,5 +1,6 @@
 obj-$(CONFIG_MTD_SPLIT)                += mtdsplit.o
 obj-$(CONFIG_MTD_SPLIT_BCM_WFI_FW) += mtdsplit_bcm_wfi.o
+obj-$(CONFIG_MTD_SPLIT_CFE_BOOTFS) += mtdsplit_cfe_bootfs.o
 obj-$(CONFIG_MTD_SPLIT_SEAMA_FW) += mtdsplit_seama.o
 obj-$(CONFIG_MTD_SPLIT_SQUASHFS_ROOT) += mtdsplit_squashfs.o
 obj-$(CONFIG_MTD_SPLIT_UIMAGE_FW) += mtdsplit_uimage.o

diff --git a/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_cfe_bootfs.c b/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_cfe_bootfs.c
new file mode 100644 (file)
index 0000000..5c8a5e1
--- /dev/null
+++ b/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_cfe_bootfs.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2021 Rafał Miłecki <rafal@milecki.pl>
+ */
+
+#include <linux/init.h>
+#include <linux/jffs2.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+
+#include "mtdsplit.h"
+
+#define je16_to_cpu(x) ((x).v16)
+#define je32_to_cpu(x) ((x).v32)
+
+#define NR_PARTS               1
+
+static int mtdsplit_cfe_bootfs_parse(struct mtd_info *mtd,
+                                    const struct mtd_partition **pparts,
+                                    struct mtd_part_parser_data *data)
+{
+       struct jffs2_raw_dirent node;
+       enum mtdsplit_part_type type;
+       struct mtd_partition *parts;
+       size_t rootfs_offset;
+       size_t retlen;
+       size_t offset;
+       int err;
+
+       /* Don't parse backup partitions */
+       if (strcmp(mtd->name, "firmware"))
+               return -EINVAL;
+
+       /* Find the end of JFFS2 bootfs partition */
+       offset = 0;
+       do {
+               err = mtd_read(mtd, offset, sizeof(node), &retlen, (void *)&node);
+               if (err || retlen != sizeof(node))
+                       break;
+
+               if (je16_to_cpu(node.magic) != JFFS2_MAGIC_BITMASK)
+                       break;
+
+               offset += je32_to_cpu(node.totlen);
+               offset = (offset + 0x3) & ~0x3;
+       } while (offset < mtd->size);
+
+       /* Find rootfs partition that follows the bootfs */
+       err = mtd_find_rootfs_from(mtd, mtd->erasesize, mtd->size, &rootfs_offset, &type);
+       if (err)
+               return err;
+
+       parts = kzalloc(NR_PARTS * sizeof(*parts), GFP_KERNEL);
+       if (!parts)
+               return -ENOMEM;
+
+       if (type == MTDSPLIT_PART_TYPE_UBI)
+               parts[0].name = UBI_PART_NAME;
+       else
+               parts[0].name = ROOTFS_PART_NAME;
+       parts[0].offset = rootfs_offset;
+       parts[0].size = mtd->size - rootfs_offset;
+
+       *pparts = parts;
+
+       return NR_PARTS;
+}
+
+static const struct of_device_id mtdsplit_cfe_bootfs_of_match_table[] = {
+       { .compatible = "brcm,bcm4908-firmware" },
+       {},
+};
+MODULE_DEVICE_TABLE(of, mtdsplit_cfe_bootfs_of_match_table);
+
+static struct mtd_part_parser mtdsplit_cfe_bootfs_parser = {
+       .owner = THIS_MODULE,
+       .name = "cfe-bootfs",
+       .of_match_table = mtdsplit_cfe_bootfs_of_match_table,
+       .parse_fn = mtdsplit_cfe_bootfs_parse,
+};
+
+module_mtd_part_parser(mtdsplit_cfe_bootfs_parser);