FWU: Add FWU metadata structure and driver for accessing metadata

In the FWU Multi Bank Update feature, the information about the
updatable images is stored as part of the metadata, which is stored on
a dedicated partition. Add the metadata structure, and a driver model
uclass which provides functions to access the metadata. These are
generic API's, and implementations can be added based on parameters
like how the metadata partition is accessed and what type of storage
device houses the metadata.

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

1 files changed, 474 insertions, 0 deletions

diff --git a/lib/fwu_updates/fwu.c b/lib/fwu_updates/fwu.c
new file mode 100644
index 0000000000..e92533ea65
--- /dev/null
+++ b/lib/fwu_updates/fwu.c
@@ -0,0 +1,474 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2022, Linaro Limited
+ */
+
+#include <dm.h>
+#include <efi_loader.h>
+#include <fwu.h>
+#include <fwu_mdata.h>
+#include <log.h>
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <u-boot/crc.h>
+
+enum {
+	IMAGE_ACCEPT_SET = 1,
+	IMAGE_ACCEPT_CLEAR,
+};
+
+enum {
+	PRIMARY_PART = 1,
+	SECONDARY_PART,
+	BOTH_PARTS,
+};
+
+static int fwu_get_dev_mdata(struct udevice **dev, struct fwu_mdata *mdata)
+{
+	int ret;
+
+	ret = uclass_first_device_err(UCLASS_FWU_MDATA, dev);
+	if (ret) {
+		log_debug("Cannot find fwu device\n");
+		return ret;
+	}
+
+	if (!mdata)
+		return 0;
+
+	ret = fwu_get_mdata(*dev, mdata);
+	if (ret < 0)
+		log_debug("Unable to get valid FWU metadata\n");
+
+	return ret;
+}
+
+static int fwu_get_image_type_id(u8 *image_index, efi_guid_t *image_type_id)
+{
+	u8 index;
+	int i;
+	struct efi_fw_image *image;
+
+	index = *image_index;
+	image = update_info.images;
+	for (i = 0; i < num_image_type_guids; i++) {
+		if (index == image[i].image_index) {
+			guidcpy(image_type_id, &image[i].image_type_id);
+			return 0;
+		}
+	}
+
+	return -ENOENT;
+}
+
+/**
+ * fwu_verify_mdata() - Verify the FWU metadata
+ * @mdata: FWU metadata structure
+ * @pri_part: FWU metadata partition is primary or secondary
+ *
+ * Verify the FWU metadata by computing the CRC32 for the metadata
+ * structure and comparing it against the CRC32 value stored as part
+ * of the structure.
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+int fwu_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_debug("crc32 check failed for %s FWU metadata partition\n",
+			  pri_part ? "primary" : "secondary");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * fwu_check_mdata_validity() - Check for validity of the FWU metadata copies
+ *
+ * Read both the metadata copies from the storage media, verify their checksum,
+ * and ascertain that both copies match. If one of the copies has gone bad,
+ * restore it from the good copy.
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+int fwu_check_mdata_validity(void)
+{
+	int ret;
+	struct udevice *dev;
+	struct fwu_mdata pri_mdata;
+	struct fwu_mdata secondary_mdata;
+	uint mdata_parts[2];
+	uint valid_partitions, invalid_partitions;
+
+	ret = fwu_get_dev_mdata(&dev, NULL);
+	if (ret)
+		return ret;
+
+	/*
+	 * Check if the platform has defined its own
+	 * function to check the metadata partitions'
+	 * validity. If so, that takes precedence.
+	 */
+	ret = fwu_mdata_check(dev);
+	if (!ret || ret != -ENOSYS)
+		return ret;
+
+	/*
+	 * Two FWU metadata partitions are expected.
+	 * If we don't have two, user needs to create
+	 * them first
+	 */
+	valid_partitions = 0;
+	ret = fwu_get_mdata_part_num(dev, mdata_parts);
+	if (ret < 0) {
+		log_debug("Error getting the FWU metadata partitions\n");
+		return -ENOENT;
+	}
+
+	ret = fwu_read_mdata_partition(dev, &pri_mdata, mdata_parts[0]);
+	if (!ret) {
+		ret = fwu_verify_mdata(&pri_mdata, 1);
+		if (!ret)
+			valid_partitions |= PRIMARY_PART;
+	}
+
+	ret = fwu_read_mdata_partition(dev, &secondary_mdata, mdata_parts[1]);
+	if (!ret) {
+		ret = fwu_verify_mdata(&secondary_mdata, 0);
+		if (!ret)
+			valid_partitions |= SECONDARY_PART;
+	}
+
+	if (valid_partitions == (PRIMARY_PART | SECONDARY_PART)) {
+		/*
+		 * Before returning, check that both the
+		 * FWU metadata copies are the same. If not,
+		 * populate the secondary partition from the
+		 * primary partition copy.
+		 */
+		if (!memcmp(&pri_mdata, &secondary_mdata,
+			    sizeof(struct fwu_mdata))) {
+			ret = 0;
+		} else {
+			log_info("Both FWU metadata copies are valid but do not match.");
+			log_info(" Restoring the secondary partition from the primary\n");
+			ret = fwu_write_mdata_partition(dev, &pri_mdata,
+							mdata_parts[1]);
+			if (ret)
+				log_debug("Restoring secondary FWU metadata partition failed\n");
+		}
+		goto out;
+	}
+
+	if (!(valid_partitions & BOTH_PARTS)) {
+		log_info("Both FWU metadata partitions invalid\n");
+		ret = -EBADMSG;
+		goto out;
+	}
+
+	invalid_partitions = valid_partitions ^ BOTH_PARTS;
+	ret = fwu_write_mdata_partition(dev,
+					(invalid_partitions == PRIMARY_PART) ?
+					&secondary_mdata : &pri_mdata,
+					(invalid_partitions == PRIMARY_PART) ?
+					mdata_parts[0] : mdata_parts[1]);
+
+	if (ret)
+		log_debug("Restoring %s FWU metadata partition failed\n",
+			  (invalid_partitions == PRIMARY_PART) ?
+			  "primary" : "secondary");
+
+out:
+	return ret;
+}
+
+/**
+ * fwu_get_active_index() - Get active_index from the FWU metadata
+ * @active_idx: active_index value to be read
+ *
+ * Read the active_index field from the FWU metadata and place it in
+ * the variable pointed to be the function argument.
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+int fwu_get_active_index(uint *active_idx)
+{
+	int ret;
+	struct udevice *dev;
+	struct fwu_mdata mdata = { 0 };
+
+	ret = fwu_get_dev_mdata(&dev, &mdata);
+	if (ret)
+		return ret;
+
+	/*
+	 * Found the FWU metadata partition, now read the active_index
+	 * value
+	 */
+	*active_idx = mdata.active_index;
+	if (*active_idx >= CONFIG_FWU_NUM_BANKS) {
+		log_debug("Active index value read is incorrect\n");
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+/**
+ * fwu_set_active_index() - Set active_index in the FWU metadata
+ * @active_idx: active_index value to be set
+ *
+ * Update the active_index field in the FWU metadata
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+int fwu_set_active_index(uint active_idx)
+{
+	int ret;
+	struct udevice *dev;
+	struct fwu_mdata mdata = { 0 };
+
+	if (active_idx >= CONFIG_FWU_NUM_BANKS) {
+		log_debug("Invalid active index value\n");
+		return -EINVAL;
+	}
+
+	ret = fwu_get_dev_mdata(&dev, &mdata);
+	if (ret)
+		return ret;
+
+	/*
+	 * 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;
+
+	/*
+	 * Now write this updated FWU metadata to both the
+	 * FWU metadata partitions
+	 */
+	ret = fwu_update_mdata(dev, &mdata);
+	if (ret) {
+		log_debug("Failed to update FWU metadata partitions\n");
+		ret = -EIO;
+	}
+
+	return ret;
+}
+
+/**
+ * fwu_get_image_index() - Get the Image Index to be used for capsule update
+ * @image_index: The Image Index for the image
+ *
+ * The FWU multi bank update feature computes the value of image_index at
+ * runtime, based on the bank to which the image needs to be written to.
+ * Derive the image_index value for the image.
+ *
+ * Currently, the capsule update driver uses the DFU framework for
+ * the updates. This function gets the DFU alt number which is to
+ * be used as the Image Index
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+int fwu_get_image_index(u8 *image_index)
+{
+	int ret, i;
+	u8 alt_num;
+	uint update_bank;
+	efi_guid_t *image_guid, image_type_id;
+	struct udevice *dev;
+	struct fwu_mdata mdata = { 0 };
+	struct fwu_image_entry *img_entry;
+	struct fwu_image_bank_info *img_bank_info;
+
+	ret = fwu_get_dev_mdata(&dev, &mdata);
+	if (ret)
+		return ret;
+
+	ret = fwu_plat_get_update_index(&update_bank);
+	if (ret) {
+		log_debug("Failed to get the FWU update bank\n");
+		goto out;
+	}
+
+	ret = fwu_get_image_type_id(image_index, &image_type_id);
+	if (ret) {
+		log_debug("Unable to get image_type_id for image_index %u\n",
+			  *image_index);
+		goto out;
+	}
+
+	ret = -EINVAL;
+	/*
+	 * 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];
+			image_guid = &img_bank_info->image_uuid;
+			ret = fwu_plat_get_alt_num(dev, image_guid, &alt_num);
+			if (ret) {
+				log_debug("alt_num not found for partition with GUID %pUs\n",
+					  image_guid);
+			} else {
+				log_debug("alt_num %d for partition %pUs\n",
+					  alt_num, image_guid);
+				*image_index = alt_num + 1;
+			}
+
+			goto out;
+		}
+	}
+
+	log_debug("Partition with the image type %pUs not found\n",
+		  &image_type_id);
+
+out:
+	return ret;
+}
+
+/**
+ * fwu_revert_boot_index() - Revert the active index in the FWU metadata
+ *
+ * Revert the active_index value in the FWU metadata, by swapping the values
+ * of active_index and previous_active_index in both copies of the
+ * FWU metadata.
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+int fwu_revert_boot_index(void)
+{
+	int ret;
+	u32 cur_active_index;
+	struct udevice *dev;
+	struct fwu_mdata mdata = { 0 };
+
+	ret = fwu_get_dev_mdata(&dev, &mdata);
+	if (ret)
+		return ret;
+
+	/*
+	 * 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;
+
+	/*
+	 * Now write this updated FWU metadata to both the
+	 * FWU metadata partitions
+	 */
+	ret = fwu_update_mdata(dev, &mdata);
+	if (ret) {
+		log_debug("Failed to update FWU metadata partitions\n");
+		ret = -EIO;
+	}
+
+	return ret;
+}
+
+/**
+ * fwu_clrset_image_accept() - Set or Clear the Acceptance bit for the image
+ * @img_type_id: GUID of the image type for which the accepted bit is to be
+ *               set or cleared
+ * @bank: Bank of which the image's Accept bit is to be set or cleared
+ * @action: Action which specifies whether image's Accept bit is to be set or
+ *          cleared
+ *
+ * Set/Clear the accepted bit for the image specified by the img_guid parameter.
+ * This indicates acceptance or rejection of image for subsequent boots by some
+ * governing component like OS(or firmware).
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+static int fwu_clrset_image_accept(efi_guid_t *img_type_id, u32 bank, u8 action)
+{
+	int ret, i;
+	struct udevice *dev;
+	struct fwu_mdata mdata = { 0 };
+	struct fwu_image_entry *img_entry;
+	struct fwu_image_bank_info *img_bank_info;
+
+	ret = fwu_get_dev_mdata(&dev, &mdata);
+	if (ret)
+		return ret;
+
+	img_entry = &mdata.img_entry[0];
+	for (i = 0; i < CONFIG_FWU_NUM_IMAGES_PER_BANK; 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;
+
+			ret = fwu_update_mdata(dev, &mdata);
+			goto out;
+		}
+	}
+
+	/* Image not found */
+	ret = -ENOENT;
+
+out:
+	return ret;
+}
+
+/**
+ * fwu_accept_image() - Set the Acceptance bit for the image
+ * @img_type_id: GUID of the image type for which the accepted bit is to be
+ *               cleared
+ * @bank: Bank of which the image's Accept bit is to be set
+ *
+ * Set the accepted bit for the image specified by the img_guid parameter. This
+ * indicates acceptance of image for subsequent boots by some governing component
+ * like OS(or firmware).
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+int fwu_accept_image(efi_guid_t *img_type_id, u32 bank)
+{
+	return fwu_clrset_image_accept(img_type_id, bank,
+				       IMAGE_ACCEPT_SET);
+}
+
+/**
+ * fwu_clear_accept_image() - Clear the Acceptance bit for the image
+ * @img_type_id: GUID of the image type for which the accepted bit is to be
+ *               cleared
+ * @bank: Bank of which the image's Accept bit is to be cleared
+ *
+ * Clear the accepted bit for the image type specified by the img_type_id parameter.
+ * This function is called after the image has been updated. The accepted bit is
+ * cleared to be set subsequently after passing the image acceptance criteria, by
+ * either the OS(or firmware)
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+int fwu_clear_accept_image(efi_guid_t *img_type_id, u32 bank)
+{
+	return fwu_clrset_image_accept(img_type_id, bank,
+				       IMAGE_ACCEPT_CLEAR);
+}