FWU: Add FWU metadata access driver for GPT partitioned block devices

In the FWU Multi Bank Update feature, the information about the
updatable images is stored as part of the metadata, on a separate
partition. Add a driver for reading from and writing to the metadata
when the updatable images and the metadata are stored on a block
device which is formatted with GPT based partition scheme.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

drivers/fwu-mdata/Kconfig

@@ -0,0 +1,16 @@
+config FWU_MDATA
+	bool "Driver support for accessing FWU Metadata"
+	depends on DM
+	help
+	  Enable support for accessing FWU Metadata partitions. The
+	  FWU Metadata partitions reside on the same storage device
+	  which contains the other FWU updatable firmware images.
+
+config FWU_MDATA_GPT_BLK
+	bool "FWU Metadata access for GPT partitioned Block devices"
+	select PARTITION_TYPE_GUID
+	select PARTITION_UUIDS
+	depends on FWU_MDATA && BLK && EFI_PARTITION
+	help
+	  Enable support for accessing FWU Metadata on GPT partitioned
+	  block devices.

drivers/fwu-mdata/Makefile

@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Copyright (c) 2022, Linaro Limited
+#
+
+
+obj-$(CONFIG_FWU_MDATA) += fwu-mdata-uclass.o
+obj-$(CONFIG_FWU_MDATA_GPT_BLK) += gpt_blk.o

drivers/fwu-mdata/gpt_blk.c

@@ -0,0 +1,290 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2022, Linaro Limited
+ */
+
+#define LOG_CATEGORY UCLASS_FWU_MDATA
+
+#include <blk.h>
+#include <dm.h>
+#include <efi_loader.h>
+#include <fwu.h>
+#include <fwu_mdata.h>
+#include <log.h>
+#include <memalign.h>
+#include <part.h>
+#include <part_efi.h>
+
+#include <dm/device-internal.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+
+enum {
+	MDATA_READ = 1,
+	MDATA_WRITE,
+};
+
+static int gpt_get_mdata_partitions(struct blk_desc *desc,
+				    uint mdata_parts[2])
+{
+	int i, ret;
+	u32 nparts;
+	efi_guid_t part_type_guid;
+	struct disk_partition info;
+	const efi_guid_t fwu_mdata_guid = FWU_MDATA_GUID;
+
+	nparts = 0;
+	for (i = 1; i < MAX_SEARCH_PARTITIONS; i++) {
+		if (part_get_info(desc, i, &info))
+			continue;
+		uuid_str_to_bin(info.type_guid, part_type_guid.b,
+				UUID_STR_FORMAT_GUID);
+
+		if (!guidcmp(&fwu_mdata_guid, &part_type_guid)) {
+			if (nparts < 2)
+				mdata_parts[nparts] = i;
+			++nparts;
+		}
+	}
+
+	if (nparts != 2) {
+		log_debug("Expect two copies of the FWU metadata instead of %d\n",
+			  nparts);
+		ret = -EINVAL;
+	} else {
+		ret = 0;
+	}
+
+	return ret;
+}
+
+static int gpt_get_mdata_disk_part(struct blk_desc *desc,
+				   struct disk_partition *info,
+				   u32 part_num)
+{
+	int ret;
+	char *mdata_guid_str = "8a7a84a0-8387-40f6-ab41-a8b9a5a60d23";
+
+	ret = part_get_info(desc, part_num, info);
+	if (ret < 0) {
+		log_debug("Unable to get the partition info for the FWU metadata part %d\n",
+			  part_num);
+		return -ENOENT;
+	}
+
+	/* Check that it is indeed the FWU metadata partition */
+	if (!strncmp(info->type_guid, mdata_guid_str, UUID_STR_LEN))
+		return 0;
+
+	return -ENOENT;
+}
+
+static int gpt_read_write_mdata(struct blk_desc *desc,
+				struct fwu_mdata *mdata,
+				u8 access, u32 part_num)
+{
+	int ret;
+	u32 len, blk_start, blkcnt;
+	struct disk_partition info;
+
+	ALLOC_CACHE_ALIGN_BUFFER_PAD(struct fwu_mdata, mdata_aligned, 1,
+				     desc->blksz);
+
+	if (!mdata)
+		return -ENOMEM;
+
+	ret = gpt_get_mdata_disk_part(desc, &info, part_num);
+	if (ret < 0) {
+		printf("Unable to get the FWU metadata partition\n");
+		return -ENOENT;
+	}
+
+	len = sizeof(*mdata);
+	blkcnt = BLOCK_CNT(len, desc);
+	if (blkcnt > info.size) {
+		log_debug("Block count exceeds FWU metadata partition size\n");
+		return -ERANGE;
+	}
+
+	blk_start = info.start;
+	if (access == MDATA_READ) {
+		if (blk_dread(desc, blk_start, blkcnt, mdata_aligned) != blkcnt) {
+			log_debug("Error reading FWU metadata from the device\n");
+			return -EIO;
+		}
+		memcpy(mdata, mdata_aligned, sizeof(struct fwu_mdata));
+	} else {
+		if (blk_dwrite(desc, blk_start, blkcnt, mdata) != blkcnt) {
+			log_debug("Error writing FWU metadata to the device\n");
+			return -EIO;
+		}
+	}
+
+	return 0;
+}
+
+static int fwu_gpt_update_mdata(struct udevice *dev, struct fwu_mdata *mdata)
+{
+	int ret;
+	struct blk_desc *desc;
+	uint mdata_parts[2];
+	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
+
+	desc = dev_get_uclass_plat(priv->blk_dev);
+
+	ret = gpt_get_mdata_partitions(desc, mdata_parts);
+	if (ret < 0) {
+		log_debug("Error getting the FWU metadata partitions\n");
+		return -ENOENT;
+	}
+
+	/* First write the primary partition */
+	ret = gpt_read_write_mdata(desc, mdata, MDATA_WRITE, mdata_parts[0]);
+	if (ret < 0) {
+		log_debug("Updating primary FWU metadata partition failed\n");
+		return ret;
+	}
+
+	/* And now the replica */
+	ret = gpt_read_write_mdata(desc, mdata, MDATA_WRITE, mdata_parts[1]);
+	if (ret < 0) {
+		log_debug("Updating secondary FWU metadata partition failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gpt_get_mdata(struct blk_desc *desc, struct fwu_mdata *mdata)
+{
+	int ret;
+	uint mdata_parts[2];
+
+	ret = gpt_get_mdata_partitions(desc, mdata_parts);
+
+	if (ret < 0) {
+		log_debug("Error getting the FWU metadata partitions\n");
+		return -ENOENT;
+	}
+
+	ret = gpt_read_write_mdata(desc, mdata, MDATA_READ, mdata_parts[0]);
+	if (ret < 0) {
+		log_debug("Failed to read the FWU metadata from the device\n");
+		return -EIO;
+	}
+
+	ret = fwu_verify_mdata(mdata, 1);
+	if (!ret)
+		return 0;
+
+	/*
+	 * Verification of the primary FWU metadata copy failed.
+	 * Try to read the replica.
+	 */
+	memset(mdata, '\0', sizeof(struct fwu_mdata));
+	ret = gpt_read_write_mdata(desc, mdata, MDATA_READ, mdata_parts[1]);
+	if (ret < 0) {
+		log_debug("Failed to read the FWU metadata from the device\n");
+		return -EIO;
+	}
+
+	ret = fwu_verify_mdata(mdata, 0);
+	if (!ret)
+		return 0;
+
+	/* Both the FWU metadata copies are corrupted. */
+	return -EIO;
+}
+
+static int fwu_gpt_get_mdata(struct udevice *dev, struct fwu_mdata *mdata)
+{
+	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
+
+	return gpt_get_mdata(dev_get_uclass_plat(priv->blk_dev), mdata);
+}
+
+static int fwu_gpt_get_mdata_partitions(struct udevice *dev, uint *mdata_parts)
+{
+	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
+
+	return gpt_get_mdata_partitions(dev_get_uclass_plat(priv->blk_dev),
+					mdata_parts);
+}
+
+static int fwu_gpt_read_mdata_partition(struct udevice *dev,
+					struct fwu_mdata *mdata, uint part_num)
+{
+	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
+
+	return gpt_read_write_mdata(dev_get_uclass_plat(priv->blk_dev),
+				    mdata, MDATA_READ, part_num);
+}
+
+static int fwu_gpt_write_mdata_partition(struct udevice *dev,
+					struct fwu_mdata *mdata, uint part_num)
+{
+	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
+
+	return gpt_read_write_mdata(dev_get_uclass_plat(priv->blk_dev),
+				    mdata, MDATA_WRITE, part_num);
+}
+
+static int fwu_get_mdata_device(struct udevice *dev, struct udevice **mdata_dev)
+{
+	u32 phandle;
+	int ret, size;
+	struct udevice *parent;
+	const fdt32_t *phandle_p = NULL;
+
+	phandle_p = dev_read_prop(dev, "fwu-mdata-store", &size);
+	if (!phandle_p) {
+		log_debug("fwu-mdata-store property not found\n");
+		return -ENOENT;
+	}
+
+	phandle = fdt32_to_cpu(*phandle_p);
+
+	ret = device_get_global_by_ofnode(ofnode_get_by_phandle(phandle),
+					  &parent);
+	if (ret)
+		return ret;
+
+	return blk_get_from_parent(parent, mdata_dev);
+}
+
+static int fwu_mdata_gpt_blk_probe(struct udevice *dev)
+{
+	int ret;
+	struct udevice *mdata_dev = NULL;
+	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
+
+	ret = fwu_get_mdata_device(dev, &mdata_dev);
+	if (ret)
+		return ret;
+
+	priv->blk_dev = mdata_dev;
+
+	return 0;
+}
+
+static const struct fwu_mdata_ops fwu_gpt_blk_ops = {
+	.get_mdata = fwu_gpt_get_mdata,
+	.update_mdata = fwu_gpt_update_mdata,
+	.get_mdata_part_num = fwu_gpt_get_mdata_partitions,
+	.read_mdata_partition = fwu_gpt_read_mdata_partition,
+	.write_mdata_partition = fwu_gpt_write_mdata_partition,
+};
+
+static const struct udevice_id fwu_mdata_ids[] = {
+	{ .compatible = "u-boot,fwu-mdata-gpt" },
+	{ }
+};
+
+U_BOOT_DRIVER(fwu_mdata_gpt_blk) = {
+	.name		= "fwu-mdata-gpt-blk",
+	.id		= UCLASS_FWU_MDATA,
+	.of_match	= fwu_mdata_ids,
+	.ops		= &fwu_gpt_blk_ops,
+	.probe		= fwu_mdata_gpt_blk_probe,
+	.priv_auto	= sizeof(struct fwu_mdata_gpt_blk_priv),
+};

include/fwu.h

@@ -14,6 +14,10 @@
 struct fwu_mdata;
 struct udevice;
 
+struct fwu_mdata_gpt_blk_priv {
+	struct udevice *blk_dev;
+};
+
 /**
  * @mdata_check: check the validity of the FWU metadata partitions
  * @get_mdata() - Get a FWU metadata copy