kernel: add seil-fw mtdsplit driver for IIJ SEIL devices

This mtdsplit parser driver parses firmware partition on Internet
Initiative Japan Inc. (IIJ) SEIL series devices.

Structure of header:

  0x0 - 0x7 : Identifier            (hex)
  0x8 - 0x57: Copyright             (ascii)
 0x58 - 0x5b: Data CRC              (hex)
 0x5c - 0x5f: Image Format Version  (hex)
 0x60 - 0x63: Image Major Version   (hex)
 0x64 - 0x67: Image Minor Version   (hex)
 0x68 - 0x87: Image Release Version (ascii)
 0x88 - 0x8b: Xor value for Data?   (hex)
 0x8c - 0x8f: Data Length           (hex)

Properties:

- compatible      : "iij,seil-firmware"
- iij,seil-id     : ID of SEIL firmware for the device (8 bytes)
  - examples:
    - SA-W2       : <0x5345494c 0x32303135> ("SEIL2015")
    - SEIL/X1     : <0x5345494c 0x2F582020> ("SEIL/X  ")
- iij,bootdev-name: boot device name assigned to the partition
                    (optional)

Signed-off-by: INAGAKI Hiroshi <musashino.open@gmail.com>

target/linux/generic/config-5.15

@@ -3878,6 +3878,7 @@ CONFIG_MTD_SPLIT_FIRMWARE_NAME="firmware"
 # CONFIG_MTD_SPLIT_LZMA_FW is not set
 # CONFIG_MTD_SPLIT_MINOR_FW is not set
 # CONFIG_MTD_SPLIT_SEAMA_FW is not set
+# CONFIG_MTD_SPLIT_SEIL_FW is not set
 CONFIG_MTD_SPLIT_SQUASHFS_ROOT=y
 CONFIG_MTD_SPLIT_SUPPORT=y
 # CONFIG_MTD_SPLIT_TPLINK_FW is not set

target/linux/generic/config-6.1

@@ -4011,6 +4011,7 @@ CONFIG_MTD_SPLIT_FIRMWARE_NAME="firmware"
 # CONFIG_MTD_SPLIT_LZMA_FW is not set
 # CONFIG_MTD_SPLIT_MINOR_FW is not set
 # CONFIG_MTD_SPLIT_SEAMA_FW is not set
+# CONFIG_MTD_SPLIT_SEIL_FW is not set
 CONFIG_MTD_SPLIT_SQUASHFS_ROOT=y
 CONFIG_MTD_SPLIT_SUPPORT=y
 # CONFIG_MTD_SPLIT_TPLINK_FW is not set

target/linux/generic/files/drivers/mtd/mtdsplit/Kconfig

@@ -105,3 +105,8 @@ config MTD_SPLIT_H3C_VFS
 	bool "Parser finding rootfs appended to H3C VFS"
 	depends on MTD_SPLIT_SUPPORT
 	select MTD_SPLIT
+
+config MTD_SPLIT_SEIL_FW
+	bool "IIJ SEIL firmware parser"
+	depends on MTD_SPLIT_SUPPORT
+	select MTD_SPLIT

target/linux/generic/files/drivers/mtd/mtdsplit/Makefile

@@ -3,6 +3,7 @@ obj-$(CONFIG_MTD_SPLIT_BCM63XX_FW) += mtdsplit_bcm63xx.o
 obj-$(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-$(CONFIG_MTD_SPLIT_SEIL_FW) += mtdsplit_seil.o
 obj-$(CONFIG_MTD_SPLIT_SQUASHFS_ROOT) += mtdsplit_squashfs.o
 obj-$(CONFIG_MTD_SPLIT_UIMAGE_FW) += mtdsplit_uimage.o
 obj-$(CONFIG_MTD_SPLIT_FIT_FW) += mtdsplit_fit.o

target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_seil.c

@@ -0,0 +1,191 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* a mtdsplit driver for IIJ SEIL devices */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/of.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/byteorder/generic.h>
+
+#include "mtdsplit.h"
+
+#define NR_PARTS		2
+#define SEIL_VFMT		1
+#define LDR_ENV_PART_NAME	"bootloader-env"
+#define LDR_ENV_KEY_BOOTDEV	"BOOTDEV"
+
+struct seil_header {
+	uint64_t	id;		/* Identifier */
+	uint8_t		copy[80];	/* Copyright */
+	uint32_t	dcrc;		/* Data CRC Checksum */
+	uint32_t	vfmt;		/* Image Version Format */
+	uint32_t	vmjr;		/* Image Version Major */
+	uint32_t	vmnr;		/* Image Version Minor */
+	uint8_t		vrel[32];	/* Image Version Release */
+	uint32_t	dxor;		/* xor value for Data? */
+	uint32_t	dlen;		/* Data Length */
+};
+
+/*
+ * check whether the current mtd device is active or not
+ *
+ * example of BOOTDEV value (IIJ SA-W2):
+ *   - "flash"   : primary image on flash
+ *   - "rescue"  : secondary image on flash
+ *   - "usb"     : usb storage
+ *   - "lan0/1"  : network
+ */
+static bool seil_bootdev_is_active(struct device_node *np)
+{
+	struct mtd_info *env_mtd;
+	char *buf, *var, *value, *eq;
+	const char *devnm;
+	size_t rdlen;
+	int ret;
+
+	/*
+	 * read bootdev name of the partition
+	 * if doesn't exist, return true and skip checking of active device
+	 */
+	ret = of_property_read_string(np, "iij,bootdev-name", &devnm);
+	if (ret == -EINVAL)
+		return true;
+	else if (ret < 0)
+		return false;
+
+	env_mtd = get_mtd_device_nm(LDR_ENV_PART_NAME);
+	if (IS_ERR(env_mtd)) {
+		pr_err("failed to get mtd device \"%s\"", LDR_ENV_PART_NAME);
+		return false;
+	}
+
+	buf = vmalloc(env_mtd->size);
+	if (!buf)
+		return false;
+
+	ret = mtd_read(env_mtd, 0, env_mtd->size, &rdlen, buf);
+	if (ret || rdlen != env_mtd->size) {
+		pr_err("failed to read from mtd (%d)\n", ret);
+		ret = 0;
+		goto exit_vfree;
+	}
+
+	for (var = buf, ret = false;
+	     var < buf + env_mtd->size && *var;
+	     var = value + strlen(value) + 1) {
+		eq = strchr(var, '=');
+		if (!eq)
+			break;
+		*eq = '\0';
+		value = eq + 1;
+
+		pr_debug("ENV: %s=%s\n", var, value);
+		if (!strcmp(var, LDR_ENV_KEY_BOOTDEV)) {
+			ret = !strcmp(devnm, value);
+			break;
+		}
+	}
+
+exit_vfree:
+	vfree(buf);
+
+	return ret;
+}
+
+static int mtdsplit_parse_seil_fw(struct mtd_info *master,
+				  const struct mtd_partition **pparts,
+				  struct mtd_part_parser_data *data)
+{
+	struct device_node *np = mtd_get_of_node(master);
+	struct mtd_partition *parts;
+	struct seil_header header;
+	size_t image_size = 0;
+	size_t rootfs_offset;
+	size_t hdrlen = sizeof(header);
+	size_t retlen;
+	int ret;
+	u64 id;
+
+	if (!seil_bootdev_is_active(np))
+		return -ENODEV;
+
+	ret = of_property_read_u64(np, "iij,seil-id", &id);
+	if (ret) {
+		pr_err("failed to get iij,seil-id from dt\n");
+		return ret;
+	}
+	pr_debug("got seil-id=0x%016llx from dt\n", id);
+
+	parts = kcalloc(NR_PARTS, sizeof(*parts), GFP_KERNEL);
+	if (!parts)
+		return -ENOMEM;
+
+	ret = mtd_read(master, 0, hdrlen, &retlen, (void *)&header);
+	if (ret)
+		goto err_free_parts;
+
+	if (retlen != hdrlen) {
+		ret = -EIO;
+		goto err_free_parts;
+	}
+
+	if (be64_to_cpu(header.id) != id ||
+	    be32_to_cpu(header.vfmt) != SEIL_VFMT) {
+		pr_debug("no valid seil image found in \"%s\"\n", master->name);
+		ret = -ENODEV;
+		goto err_free_parts;
+	}
+
+	image_size = hdrlen + be32_to_cpu(header.dlen);
+	if (image_size > master->size) {
+		pr_err("seil image exceeds MTD device \"%s\"\n", master->name);
+		ret = -EINVAL;
+		goto err_free_parts;
+	}
+
+	/* find the roots after the seil image */
+	ret = mtd_find_rootfs_from(master, image_size,
+				   master->size, &rootfs_offset, NULL);
+	if (ret || (master->size - rootfs_offset) == 0) {
+		pr_debug("no rootfs after seil image in \"%s\"\n",
+			 master->name);
+		ret = -ENODEV;
+		goto err_free_parts;
+	}
+
+	parts[0].name = KERNEL_PART_NAME;
+	parts[0].offset = 0;
+	parts[0].size = rootfs_offset;
+
+	parts[1].name = ROOTFS_PART_NAME;
+	parts[1].offset = rootfs_offset;
+	parts[1].size = master->size - rootfs_offset;
+
+	*pparts = parts;
+	return NR_PARTS;
+
+err_free_parts:
+	kfree(parts);
+	return ret;
+}
+
+static const struct of_device_id mtdsplit_seil_fw_of_match_table[] = {
+	{ .compatible = "iij,seil-firmware" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mtdsplit_seil_fw_of_match_table);
+
+static struct mtd_part_parser mtdsplit_seil_fw_parser = {
+	.owner = THIS_MODULE,
+	.name = "seil-fw",
+	.of_match_table = mtdsplit_seil_fw_of_match_table,
+	.parse_fn = mtdsplit_parse_seil_fw,
+	.type = MTD_PARSER_TYPE_FIRMWARE,
+};
+
+module_mtd_part_parser(mtdsplit_seil_fw_parser);