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>
diff --git a/include/fwu.h b/include/fwu.h
new file mode 100644
index 0000000..a83ea19
--- /dev/null
+++ b/include/fwu.h
@@ -0,0 +1,311 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2022, Linaro Limited
+ */
+
+#if !defined _FWU_H_
+#define _FWU_H_
+
+#include <blk.h>
+#include <efi.h>
+
+#include <linux/types.h>
+
+struct fwu_mdata;
+struct udevice;
+
+/**
+ * @mdata_check: check the validity of the FWU metadata partitions
+ * @get_mdata() - Get a FWU metadata copy
+ * @update_mdata() - Update the FWU metadata copy
+ */
+struct fwu_mdata_ops {
+ /**
+ * check_mdata() - Check if the FWU metadata is valid
+ * @dev: FWU device
+ *
+ * Validate both copies of the FWU metadata. If one of the copies
+ * has gone bad, restore it from the other copy.
+ *
+ * Return: 0 if OK, -ve on error
+ */
+ int (*check_mdata)(struct udevice *dev);
+
+ /**
+ * get_mdata() - Get a FWU metadata copy
+ * @dev: FWU device
+ * @mdata: Pointer to FWU metadata
+ *
+ * Get a valid copy of the FWU metadata.
+ *
+ * Return: 0 if OK, -ve on error
+ */
+ int (*get_mdata)(struct udevice *dev, struct fwu_mdata *mdata);
+
+ /**
+ * update_mdata() - Update the FWU metadata
+ * @dev: FWU device
+ * @mdata: Copy of the FWU metadata
+ *
+ * Update the FWU metadata structure by writing to the
+ * FWU metadata partitions.
+ *
+ * Return: 0 if OK, -ve on error
+ */
+ int (*update_mdata)(struct udevice *dev, struct fwu_mdata *mdata);
+
+ /**
+ * get_mdata_part_num() - Get the FWU metadata partition numbers
+ * @dev: FWU metadata device
+ * @mdata_parts: array for storing the metadata partition numbers
+ *
+ * Get the partition numbers on the storage device on which the
+ * FWU metadata is stored. Two partition numbers will be returned.
+ *
+ * Return: 0 if OK, -ve on error
+ */
+ int (*get_mdata_part_num)(struct udevice *dev, uint *mdata_parts);
+
+ /**
+ * read_mdata_partition() - Read the FWU metadata from a partition
+ * @dev: FWU metadata device
+ * @mdata: Copy of the FWU metadata
+ * @part_num: Partition number from which FWU metadata is to be read
+ *
+ * Read the FWU metadata from the specified partition number
+ *
+ * Return: 0 if OK, -ve on error
+ */
+ int (*read_mdata_partition)(struct udevice *dev,
+ struct fwu_mdata *mdata, uint part_num);
+
+ /**
+ * write_mdata_partition() - Write the FWU metadata to a partition
+ * @dev: FWU metadata device
+ * @mdata: Copy of the FWU metadata
+ * @part_num: Partition number to which FWU metadata is to be written
+ *
+ * Write the FWU metadata to the specified partition number
+ *
+ * Return: 0 if OK, -ve on error
+ */
+ int (*write_mdata_partition)(struct udevice *dev,
+ struct fwu_mdata *mdata, uint part_num);
+};
+
+#define FWU_MDATA_VERSION 0x1
+
+/*
+* GUID value defined in the FWU specification for identification
+* of the FWU metadata partition.
+*/
+#define FWU_MDATA_GUID \
+ EFI_GUID(0x8a7a84a0, 0x8387, 0x40f6, 0xab, 0x41, \
+ 0xa8, 0xb9, 0xa5, 0xa6, 0x0d, 0x23)
+
+/**
+ * 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);
+
+/**
+ * fwu_get_mdata_part_num() - Get the FWU metadata partition numbers
+ * @dev: FWU metadata device
+ * @mdata_parts: array for storing the metadata partition numbers
+ *
+ * Get the partition numbers on the storage device on which the
+ * FWU metadata is stored. Two partition numbers will be returned
+ * through the array.
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+int fwu_get_mdata_part_num(struct udevice *dev, uint *mdata_parts);
+
+/**
+ * fwu_read_mdata_partition() - Read the FWU metadata from a partition
+ * @dev: FWU metadata device
+ * @mdata: Copy of the FWU metadata
+ * @part_num: Partition number from which FWU metadata is to be read
+ *
+ * Read the FWU metadata from the specified partition number
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+int fwu_read_mdata_partition(struct udevice *dev, struct fwu_mdata *mdata,
+ uint part_num);
+
+/**
+ * fwu_write_mdata_partition() - Write the FWU metadata to a partition
+ * @dev: FWU metadata device
+ * @mdata: Copy of the FWU metadata
+ * @part_num: Partition number to which FWU metadata is to be written
+ *
+ * Write the FWU metadata to the specified partition number
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+int fwu_write_mdata_partition(struct udevice *dev, struct fwu_mdata *mdata,
+ uint part_num);
+
+/**
+ * fwu_get_mdata() - Get a FWU metadata copy
+ * @dev: FWU metadata device
+ * @mdata: Copy of the FWU metadata
+ *
+ * Get a valid copy of the FWU metadata.
+ *
+ * Note: This function is to be called first when modifying any fields
+ * in the metadata. The sequence of calls to modify any field in the
+ * metadata would be 1) fwu_get_mdata 2) Modify metadata, followed by
+ * 3) fwu_update_mdata
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+int fwu_get_mdata(struct udevice *dev, struct fwu_mdata *mdata);
+
+/**
+ * fwu_update_mdata() - Update the FWU metadata
+ * @dev: FWU metadata device
+ * @mdata: Copy of the FWU metadata
+ *
+ * Update the FWU metadata structure by writing to the
+ * FWU metadata partitions.
+ *
+ * Note: This function is not to be called directly to update the
+ * metadata fields. The sequence of function calls should be
+ * 1) fwu_get_mdata() 2) Modify the medata fields 3) fwu_update_mdata()
+ *
+ * The sequence of updating the partitions should be, update the
+ * primary metadata partition (first partition encountered), followed
+ * by updating the secondary partition. With this update sequence, in
+ * the rare scenario that the two metadata partitions are valid but do
+ * not match, maybe due to power outage at the time of updating the
+ * metadata copies, the secondary partition can be updated from the
+ * primary.
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+int fwu_update_mdata(struct udevice *dev, struct fwu_mdata *mdata);
+
+/**
+ * fwu_get_active_index() - Get active_index from the FWU metadata
+ * @active_idxp: 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_idxp);
+
+/**
+ * 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);
+
+/**
+ * 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);
+
+/**
+ * fwu_mdata_check() - Check if the FWU metadata is valid
+ * @dev: FWU metadata device
+ *
+ * Validate both copies of the FWU metadata. If one of the copies
+ * has gone bad, restore it from the other copy.
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+int fwu_mdata_check(struct udevice *dev);
+
+/**
+ * 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);
+
+/**
+ * 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);
+
+/**
+ * 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);
+
+/**
+ * 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);
+
+#endif /* _FWU_H_ */