[RFC PATCH v2 2/8] FWU: Add FWU metadata access functions for GPT partitioned block devices

[Sughosh Ganu <sughosh.ganu@linaro.org>]

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 functions for reading from and writing to the metadata
when the updatable images and the metadata are stored on a block
device which is formated with GPT based partition scheme.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
---
Changes since V1:
* Rename metadata with mdata for all symbols
* Use BIT for all macros
* Use the logic suggested by Patrick to get the partition
  type guids and partition guid's instead of defining a new
  api
* Call the platform function fwu_plat_get_alt_num for
  getting the alt_num for the image partition, instead of
  the earlier hard-coded approach.
* Change the logic in gpt_check_mdata_validity as suggested
  by Ilias.
* Other smaller code style changes suggested by Ilias

 include/fwu_mdata.h                 |   2 +
 lib/fwu_updates/fwu_mdata_gpt_blk.c | 634 ++++++++++++++++++++++++++++
 2 files changed, 636 insertions(+)
 create mode 100644 lib/fwu_updates/fwu_mdata_gpt_blk.c

diff --git a/include/fwu_mdata.h b/include/fwu_mdata.h
index 11eb570012..9e24ab4047 100644
--- a/include/fwu_mdata.h
+++ b/include/fwu_mdata.h
@@ -99,4 +99,6 @@ struct fwu_mdata_ops {
 int fwu_get_mdata(struct fwu_mdata **mdata);
 struct fwu_mdata_ops *get_plat_fwu_mdata_ops(void);
 
+extern struct fwu_mdata_ops fwu_gpt_blk_ops;
+
 #endif /* _FWU_MDATA_H_ */
diff --git a/lib/fwu_updates/fwu_mdata_gpt_blk.c b/lib/fwu_updates/fwu_mdata_gpt_blk.c
new file mode 100644
index 0000000000..2dcac0c3d4
--- /dev/null
+++ b/lib/fwu_updates/fwu_mdata_gpt_blk.c
@@ -0,0 +1,634 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2021, Linaro Limited
+ */
+
+#include <blk.h>
+#include <efi_loader.h>
+#include <fwu.h>
+#include <fwu_mdata.h>
+#include <malloc.h>
+#include <memalign.h>
+#include <part.h>
+#include <part_efi.h>
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <u-boot/crc.h>
+
+#define PRIMARY_PART		BIT(0)
+#define SECONDARY_PART		BIT(1)
+#define BOTH_PARTS		(PRIMARY_PART | SECONDARY_PART)
+
+#define MDATA_READ		BIT(0)
+#define MDATA_WRITE		BIT(1)
+
+#define IMAGE_ACCEPT_SET	BIT(0)
+#define IMAGE_ACCEPT_CLEAR	BIT(1)
+
+static int gpt_verify_mdata(struct fwu_mdata *mdata, bool pri_part)
+{
+	u32 calc_crc32;
+	void *buf;
+
+	buf = &mdata->version;
+	calc_crc32 = crc32(0, buf, sizeof(*mdata) - sizeof(u32));
+
+	if (calc_crc32 != mdata->crc32) {
+		log_err("crc32 check failed for %s FWU metadata partition\n",
+			pri_part ? "primary" : "secondary");
+		return -1;
+	}
+
+	return 0;
+}
+
+static int gpt_get_mdata_partitions(struct blk_desc *desc,
+				    u16 *primary_mpart,
+				    u16 *secondary_mpart)
+{
+	int i, ret;
+	u32 mdata_parts;
+	efi_guid_t part_type_guid;
+	struct disk_partition info;
+	const efi_guid_t fwu_mdata_guid = FWU_MDATA_GUID;
+
+	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)) {
+			++mdata_parts;
+			if (!*primary_mpart)
+				*primary_mpart = i;
+			else
+				*secondary_mpart = i;
+		}
+	}
+
+	if (mdata_parts != 2) {
+		log_err("Expect two copies of the FWU metadata instead of %d\n",
+			mdata_parts);
+		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_err("Unable to get the partition info for the FWU metadata part %d",
+			part_num);
+		return -1;
+	}
+
+	/* Check that it is indeed the FWU metadata partition */
+	if (!strncmp(info->type_guid, mdata_guid_str, UUID_STR_LEN)) {
+		/* Found the FWU metadata partition */
+		return 0;
+	}
+
+	return -1;
+}
+
+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);
+
+	ret = gpt_get_mdata_disk_part(desc, &info, part_num);
+	if (ret < 0) {
+		printf("Unable to get the FWU metadata partition\n");
+		return -ENODEV;
+	}
+
+	len = sizeof(*mdata);
+	blkcnt = BLOCK_CNT(len, desc);
+	if (blkcnt > info.size) {
+		log_err("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_err("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_err("Error writing FWU metadata to the device\n");
+			return -EIO;
+		}
+	}
+
+	return 0;
+}
+
+static int gpt_read_mdata(struct blk_desc *desc,
+			  struct fwu_mdata *mdata, u32 part_num)
+{
+	return gpt_read_write_mdata(desc, mdata, MDATA_READ, part_num);
+}
+
+static int gpt_write_mdata_partition(struct blk_desc *desc,
+					struct fwu_mdata *mdata,
+					u32 part_num)
+{
+	return gpt_read_write_mdata(desc, mdata, MDATA_WRITE, part_num);
+}
+
+static int gpt_update_mdata(struct fwu_mdata *mdata)
+{
+	int ret;
+	struct blk_desc *desc;
+	u16 primary_mpart = 0, secondary_mpart = 0;
+
+	ret = fwu_plat_get_blk_desc(&desc);
+	if (ret < 0) {
+		log_err("Block device not found\n");
+		return -ENODEV;
+	}
+
+	ret = gpt_get_mdata_partitions(desc, &primary_mpart,
+					  &secondary_mpart);
+
+	if (ret < 0) {
+		log_err("Error getting the FWU metadata partitions\n");
+		return -ENODEV;
+	}
+
+	/* First write the primary partition*/
+	ret = gpt_write_mdata_partition(desc, mdata, primary_mpart);
+	if (ret < 0) {
+		log_err("Updating primary FWU metadata partition failed\n");
+		return ret;
+	}
+
+	/* And now the replica */
+	ret = gpt_write_mdata_partition(desc, mdata, secondary_mpart);
+	if (ret < 0) {
+		log_err("Updating secondary FWU metadata partition failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gpt_get_mdata(struct fwu_mdata **mdata)
+{
+	int ret;
+	struct blk_desc *desc;
+	u16 primary_mpart = 0, secondary_mpart = 0;
+
+	ret = fwu_plat_get_blk_desc(&desc);
+	if (ret < 0) {
+		log_err("Block device not found\n");
+		return -ENODEV;
+	}
+
+	ret = gpt_get_mdata_partitions(desc, &primary_mpart,
+				       &secondary_mpart);
+
+	if (ret < 0) {
+		log_err("Error getting the FWU metadata partitions\n");
+		return -ENODEV;
+	}
+
+	*mdata = malloc(sizeof(struct fwu_mdata));
+	if (!*mdata) {
+		log_err("Unable to allocate memory for reading FWU metadata\n");
+		return -ENOMEM;
+	}
+
+	ret = gpt_read_mdata(desc, *mdata, primary_mpart);
+	if (ret < 0) {
+		log_err("Failed to read the FWU metadata from the device\n");
+		return -EIO;
+	}
+
+	ret = gpt_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_mdata(desc, *mdata, secondary_mpart);
+	if (ret < 0) {
+		log_err("Failed to read the FWU metadata from the device\n");
+		return -EIO;
+	}
+
+	ret = gpt_verify_mdata(*mdata, 0);
+	if (!ret)
+		return 0;
+
+	/* Both the FWU metadata copies are corrupted. */
+	return -1;
+}
+
+static int gpt_check_mdata_validity(void)
+{
+	int ret;
+	struct blk_desc *desc;
+	struct fwu_mdata pri_mdata;
+	struct fwu_mdata secondary_mdata;
+	u16 primary_mpart = 0, secondary_mpart = 0;
+	u16 valid_partitions, invalid_partitions;
+
+	ret = fwu_plat_get_blk_desc(&desc);
+	if (ret < 0) {
+		log_err("Block device not found\n");
+		return -ENODEV;
+	}
+
+	/*
+	 * Two FWU metadata partitions are expected.
+	 * If we don't have two, user needs to create
+	 * them first
+	 */
+	valid_partitions = 0;
+	ret = gpt_get_mdata_partitions(desc, &primary_mpart,
+				       &secondary_mpart);
+
+	if (ret < 0) {
+		log_err("Error getting the FWU metadata partitions\n");
+		return -ENODEV;
+	}
+
+	ret = gpt_read_mdata(desc, &pri_mdata, primary_mpart);
+	if (ret < 0) {
+		log_err("Failed to read the FWU metadata from the device\n");
+		goto secondary_read;
+	}
+
+	ret = gpt_verify_mdata(&pri_mdata, 1);
+	if (!ret)
+		valid_partitions |= PRIMARY_PART;
+
+secondary_read:
+	/* Now check the secondary partition */
+	ret = gpt_read_mdata(desc, &secondary_mdata, secondary_mpart);
+	if (ret < 0) {
+		log_err("Failed to read the FWU metadata from the device\n");
+		goto mdata_restore;
+	}
+
+	ret = gpt_verify_mdata(&secondary_mdata, 0);
+	if (!ret)
+		valid_partitions |= SECONDARY_PART;
+
+mdata_restore:
+	if (valid_partitions == (PRIMARY_PART | SECONDARY_PART)) {
+		ret = -1;
+		/*
+		 * Before returning, check that both the
+		 * FWU metadata copies are the same. If not,
+		 * the FWU metadata copies need to be
+		 * re-populated.
+		 */
+		if (!memcmp(&pri_mdata, &secondary_mdata,
+			    sizeof(struct fwu_mdata))) {
+			ret = 0;
+		} else {
+			log_err("Both FWU metadata copies are valid but do not match. Please check!\n");
+		}
+		goto out;
+	}
+
+	ret = -1;
+	if (!(valid_partitions & BOTH_PARTS))
+		goto out;
+
+	invalid_partitions = valid_partitions ^ BOTH_PARTS;
+	ret = gpt_write_mdata_partition(desc,
+					(invalid_partitions == PRIMARY_PART) ?
+					&secondary_mdata : &pri_mdata,
+					(invalid_partitions == PRIMARY_PART) ?
+					primary_mpart : secondary_mpart);
+
+	if (ret < 0)
+		log_err("Restoring %s FWU metadata partition failed\n",
+			(invalid_partitions == PRIMARY_PART) ?
+			"primary" : "secondary");
+
+out:
+	return ret;
+}
+
+int fwu_gpt_get_active_index(u32 *active_idx)
+{
+	int ret;
+	struct fwu_mdata *mdata;
+
+	ret = gpt_get_mdata(&mdata);
+	if (ret < 0) {
+		log_err("Unable to get valid FWU metadata\n");
+		goto out;
+	}
+
+	/*
+	 * Found the FWU metadata partition, now read the active_index
+	 * value
+	 */
+	*active_idx = mdata->active_index;
+	if (*active_idx > CONFIG_FWU_NUM_BANKS - 1) {
+		printf("Active index value read is incorrect\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+out:
+	free(mdata);
+
+	return ret;
+}
+
+static int gpt_get_image_alt_num(struct blk_desc *desc,
+				 efi_guid_t image_type_id,
+				 u32 update_bank, int *alt_no)
+{
+	int ret, i;
+	u32 part;
+	struct fwu_mdata *mdata;
+	struct fwu_image_entry *img_entry;
+	struct fwu_image_bank_info *img_bank_info;
+	struct disk_partition info;
+	efi_guid_t unique_part_guid;
+	efi_guid_t image_guid = NULL_GUID;
+
+	ret = gpt_get_mdata(&mdata);
+	if (ret < 0) {
+		log_err("Unable to read valid FWU metadata\n");
+		goto out;
+	}
+
+	/*
+	 * The FWU metadata has been read. Now get the image_uuid for the
+	 * image with the update_bank.
+	 */
+	for (i = 0; i < CONFIG_FWU_NUM_IMAGES_PER_BANK; i++) {
+		if (!guidcmp(&image_type_id,
+			     &mdata->img_entry[i].image_type_uuid)) {
+			img_entry = &mdata->img_entry[i];
+			img_bank_info = &img_entry->img_bank_info[update_bank];
+			guidcpy(&image_guid, &img_bank_info->image_uuid);
+			break;
+		}
+	}
+
+	/*
+	 * Now read the GPT Partition Table Entries to find a matching
+	 * partition with UniquePartitionGuid value. We need to iterate
+	 * through all the GPT partitions since they might be in any
+	 * order
+	 */
+	for (i = 1; i < MAX_SEARCH_PARTITIONS; i++) {
+		if (part_get_info(desc, i, &info))
+			continue;
+		uuid_str_to_bin(info.uuid, unique_part_guid.b,
+				UUID_STR_FORMAT_GUID);
+
+		if (!guidcmp(&unique_part_guid, &image_guid)) {
+			/* Found the partition */
+			part = i;
+			*alt_no = fwu_plat_get_alt_num(desc->devnum, &part);
+			if (*alt_no != -1)
+				log_info("alt_num %d for partition %pUl\n",
+					  *alt_no, &image_guid);
+			ret = 0;
+			break;
+		}
+	}
+
+	if (*alt_no == -1) {
+		log_err("alt_num not found for partition with GUID %pUl\n",
+			&image_guid);
+		ret = -EINVAL;
+	}
+
+	if (i == MAX_SEARCH_PARTITIONS) {
+		log_err("Partition with the image guid not found\n");
+		ret = -EINVAL;
+	}
+
+out:
+	free(mdata);
+
+	return ret;
+}
+
+int fwu_gpt_update_active_index(u32 active_idx)
+{
+	int ret;
+	void *buf;
+	struct fwu_mdata *mdata;
+
+	if (active_idx > CONFIG_FWU_NUM_BANKS) {
+		printf("Active index value to be updated is incorrect\n");
+		return -1;
+	}
+
+	ret = gpt_get_mdata(&mdata);
+	if (ret < 0) {
+		log_err("Unable to get valid FWU metadata\n");
+		goto out;
+	}
+
+	/*
+	 * Update the active index and previous_active_index fields
+	 * in the FWU metadata
+	 */
+	mdata->previous_active_index = mdata->active_index;
+	mdata->active_index = active_idx;
+
+
+	/*
+	 * Calculate the crc32 for the updated FWU metadata
+	 * and put the updated value in the FWU metadata crc32
+	 * field
+	 */
+	buf = &mdata->version;
+	mdata->crc32 = crc32(0, buf, sizeof(*mdata) - sizeof(u32));
+
+	/*
+	 * Now write this updated FWU metadata to both the
+	 * FWU metadata partitions
+	 */
+	ret = gpt_update_mdata(mdata);
+	if (ret < 0) {
+		log_err("Failed to update FWU metadata partitions\n");
+		ret = -EIO;
+	}
+
+out:
+	free(mdata);
+
+	return ret;
+}
+
+int fwu_gpt_get_image_alt_num(efi_guid_t image_type_id, u32 update_bank,
+			      int *alt_no)
+{
+	int ret;
+	struct blk_desc *desc;
+
+	ret = fwu_plat_get_blk_desc(&desc);
+	if (ret < 0) {
+		log_err("Block device not found\n");
+		return -ENODEV;
+	}
+
+	return gpt_get_image_alt_num(desc, image_type_id, update_bank, alt_no);
+}
+
+int fwu_gpt_mdata_check(void)
+{
+	/*
+	 * Check if both the copies of the FWU metadata are
+	 * valid. If one has gone bad, restore it from the
+	 * other good copy.
+	 */
+	return gpt_check_mdata_validity();
+}
+
+int fwu_gpt_get_mdata(struct fwu_mdata **mdata)
+{
+	return gpt_get_mdata(mdata);
+}
+
+int fwu_gpt_revert_boot_index(void)
+{
+	int ret;
+	void *buf;
+	u32 cur_active_index;
+	struct fwu_mdata *mdata;
+
+	ret = gpt_get_mdata(&mdata);
+	if (ret < 0) {
+		log_err("Unable to get valid FWU metadata\n");
+		goto out;
+	}
+
+	/*
+	 * Swap the active index and previous_active_index fields
+	 * in the FWU metadata
+	 */
+	cur_active_index = mdata->active_index;
+	mdata->active_index = mdata->previous_active_index;
+	mdata->previous_active_index = cur_active_index;
+
+	/*
+	 * Calculate the crc32 for the updated FWU metadata
+	 * and put the updated value in the FWU metadata crc32
+	 * field
+	 */
+	buf = &mdata->version;
+	mdata->crc32 = crc32(0, buf, sizeof(*mdata) - sizeof(u32));
+
+	/*
+	 * Now write this updated FWU metadata to both the
+	 * FWU metadata partitions
+	 */
+	ret = gpt_update_mdata(mdata);
+	if (ret < 0) {
+		log_err("Failed to update FWU metadata partitions\n");
+		ret = -EIO;
+	}
+
+out:
+	free(mdata);
+
+	return ret;
+}
+
+static int fwu_gpt_set_clear_image_accept(efi_guid_t *img_type_id,
+					  u32 bank, u8 action)
+{
+	void *buf;
+	int ret, i;
+	u32 nimages;
+	struct fwu_mdata *mdata;
+	struct fwu_image_entry *img_entry;
+	struct fwu_image_bank_info *img_bank_info;
+
+	ret = gpt_get_mdata(&mdata);
+	if (ret < 0) {
+		log_err("Unable to get valid FWU metadata\n");
+		goto out;
+	}
+
+	if (action == IMAGE_ACCEPT_SET)
+		bank = mdata->active_index;
+
+	nimages = CONFIG_FWU_NUM_IMAGES_PER_BANK;
+	img_entry = &mdata->img_entry[0];
+	for (i = 0; i < nimages; i++) {
+		if (!guidcmp(&img_entry[i].image_type_uuid, img_type_id)) {
+			img_bank_info = &img_entry[i].img_bank_info[bank];
+			if (action == IMAGE_ACCEPT_SET)
+				img_bank_info->accepted |= FWU_IMAGE_ACCEPTED;
+			else
+				img_bank_info->accepted = 0;
+
+			buf = &mdata->version;
+			mdata->crc32 = crc32(0, buf, sizeof(*mdata) -
+					     sizeof(u32));
+
+			ret = gpt_update_mdata(mdata);
+			goto out;
+		}
+	}
+
+	/* Image not found */
+	ret = -EINVAL;
+
+out:
+	free(mdata);
+
+	return ret;
+}
+
+int fwu_gpt_accept_image(efi_guid_t *img_type_id)
+{
+	return fwu_gpt_set_clear_image_accept(img_type_id, 0,
+					      IMAGE_ACCEPT_SET);
+}
+
+int fwu_gpt_clear_accept_image(efi_guid_t *img_type_id, u32 bank)
+{
+	return fwu_gpt_set_clear_image_accept(img_type_id, bank,
+					      IMAGE_ACCEPT_CLEAR);
+}
+
+struct fwu_mdata_ops fwu_gpt_blk_ops = {
+	.get_active_index = fwu_gpt_get_active_index,
+	.update_active_index = fwu_gpt_update_active_index,
+	.get_image_alt_num = fwu_gpt_get_image_alt_num,
+	.mdata_check = fwu_gpt_mdata_check,
+	.revert_boot_index = fwu_gpt_revert_boot_index,
+	.set_accept_image = fwu_gpt_accept_image,
+	.clear_accept_image = fwu_gpt_clear_accept_image,
+	.get_mdata = fwu_gpt_get_mdata,
+};
-- 
2.17.1