Hello Sughosh,

On Wed, 28 Sept 2022 at 11:30, Sughosh Ganu <sughosh.g...@linaro.org> wrote:
>
> 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.g...@linaro.org>
> Reviewed-by: Patrick Delaunay <patrick.delau...@foss.st.com>
> Reviewed-by: Etienne Carriere <etienne.carri...@linaro.org>
> ---
> Changes since V10:
> * s/fwu_update_active_index/fwu_set_active_index as per comment from
>   Jassi
> * Change the argument type of fwu_set_active_index() to uint from u32
>   as per comment from Jassi
> * s/mdata_check/check_mdata as per comment from Jassi
> * Fix the typo in the function comment of fwu_mdata_check()
>
>  drivers/fwu-mdata/fwu-mdata-uclass.c | 107 ++++++++
>  include/dm/uclass-id.h               |   1 +
>  include/fwu.h                        | 211 ++++++++++++++++
>  include/fwu_mdata.h                  |  67 +++++
>  lib/fwu_updates/fwu.c                | 363 +++++++++++++++++++++++++++
>  5 files changed, 749 insertions(+)
>  create mode 100644 drivers/fwu-mdata/fwu-mdata-uclass.c
>  create mode 100644 include/fwu.h
>  create mode 100644 include/fwu_mdata.h
>  create mode 100644 lib/fwu_updates/fwu.c
>
> diff --git a/drivers/fwu-mdata/fwu-mdata-uclass.c 
> b/drivers/fwu-mdata/fwu-mdata-uclass.c
> new file mode 100644
> index 0000000000..4237b89520
> --- /dev/null
> +++ b/drivers/fwu-mdata/fwu-mdata-uclass.c
> @@ -0,0 +1,107 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2022, Linaro Limited
> + */
> +
> +#define LOG_CATEGORY UCLASS_FWU_MDATA
> +
> +#include <common.h>
> +#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>
> +
> +/**
> + * 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)
> +{
> +       const struct fwu_mdata_ops *ops = device_get_ops(dev);
> +
> +       if (!ops->check_mdata) {
> +               log_debug("check_mdata() method not defined\n");
> +               return -ENOSYS;
> +       }
> +
> +       return ops->check_mdata(dev);
> +}
> +
> +/**
> + * 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)
> +{
> +       const struct fwu_mdata_ops *ops = device_get_ops(dev);
> +
> +       if (!ops->get_mdata) {
> +               log_debug("get_mdata() method not defined\n");
> +               return -ENOSYS;
> +       }
> +
> +       return ops->get_mdata(dev, 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()
> + *
> + * Return: 0 if OK, -ve on error
> + *
> + */
> +int fwu_update_mdata(struct udevice *dev, struct fwu_mdata *mdata)
> +{
> +       void *buf;
> +       const struct fwu_mdata_ops *ops = device_get_ops(dev);
> +
> +       if (!ops->update_mdata) {
> +               log_debug("get_mdata() method not defined\n");
> +               return -ENOSYS;
> +       }
> +
> +       /*
> +        * 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));
> +
> +       return ops->update_mdata(dev, mdata);
> +}
> +
> +UCLASS_DRIVER(fwu_mdata) = {
> +       .id             = UCLASS_FWU_MDATA,
> +       .name           = "fwu-mdata",
> +};
> diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
> index a432e43871..598a8c10a0 100644
> --- a/include/dm/uclass-id.h
> +++ b/include/dm/uclass-id.h
> @@ -58,6 +58,7 @@ enum uclass_id {
>         UCLASS_FIRMWARE,        /* Firmware */
>         UCLASS_FUZZING_ENGINE,  /* Fuzzing engine */
>         UCLASS_FS_FIRMWARE_LOADER,              /* Generic loader */
> +       UCLASS_FWU_MDATA,       /* FWU Metadata Access */
>         UCLASS_GPIO,            /* Bank of general-purpose I/O pins */
>         UCLASS_HASH,            /* Hash device */
>         UCLASS_HWSPINLOCK,      /* Hardware semaphores */
> diff --git a/include/fwu.h b/include/fwu.h
> new file mode 100644
> index 0000000000..a4d2d35d9a
> --- /dev/null
> +++ b/include/fwu.h
> @@ -0,0 +1,211 @@
> +/* 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);
> +};
> +
> +#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_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()
> + *
> + * 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_ */
> diff --git a/include/fwu_mdata.h b/include/fwu_mdata.h
> new file mode 100644
> index 0000000000..8fda4f4ac2
> --- /dev/null
> +++ b/include/fwu_mdata.h
> @@ -0,0 +1,67 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright (c) 2022, Linaro Limited
> + */
> +
> +#if !defined _FWU_MDATA_H_
> +#define _FWU_MDATA_H_
> +
> +#include <efi.h>
> +
> +/**
> + * struct fwu_image_bank_info - firmware image information
> + * @image_uuid: Guid value of the image in this bank
> + * @accepted: Acceptance status of the image
> + * @reserved: Reserved
> + *
> + * The structure contains image specific fields which are
> + * used to identify the image and to specify the image's
> + * acceptance status
> + */
> +struct fwu_image_bank_info {
> +       efi_guid_t  image_uuid;
> +       uint32_t accepted;
> +       uint32_t reserved;
> +};
> +
> +/**
> + * struct fwu_image_entry - information for a particular type of image
> + * @image_type_uuid: Guid value for identifying the image type
> + * @location_uuid: Guid of the storage volume where the image is located
> + * @img_bank_info: Array containing properties of images
> + *
> + * This structure contains information on various types of updatable
> + * firmware images. Each image type then contains an array of image
> + * information per bank.
> + */
> +struct fwu_image_entry {
> +       efi_guid_t image_type_uuid;
> +       efi_guid_t location_uuid;
> +       struct fwu_image_bank_info img_bank_info[CONFIG_FWU_NUM_BANKS];
> +};
> +
> +/**
> + * struct fwu_mdata - FWU metadata structure for multi-bank updates
> + * @crc32: crc32 value for the FWU metadata
> + * @version: FWU metadata version
> + * @active_index: Index of the bank currently used for booting images
> + * @previous_active_inde: Index of the bank used before the current bank
> + *                        being used for booting
> + * @img_entry: Array of information on various firmware images that can
> + *             be updated
> + *
> + * This structure is used to store all the needed information for performing
> + * multi bank updates on the platform. This contains info on the bank being
> + * used to boot along with the information needed for identification of
> + * individual images
> + */
> +struct fwu_mdata {
> +       uint32_t crc32;
> +       uint32_t version;
> +       uint32_t active_index;
> +       uint32_t previous_active_index;
> +
> +       struct fwu_image_entry img_entry[CONFIG_FWU_NUM_IMAGES_PER_BANK];
> +};
> +
> +#endif /* _FWU_MDATA_H_ */
> diff --git a/lib/fwu_updates/fwu.c b/lib/fwu_updates/fwu.c
> new file mode 100644
> index 0000000000..fe8058bc37
> --- /dev/null
> +++ b/lib/fwu_updates/fwu.c
> @@ -0,0 +1,363 @@
> +// 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>
> +
> +#define IMAGE_ACCEPT_SET       BIT(0)
> +#define IMAGE_ACCEPT_CLEAR     BIT(1)

Nitpicking: i think an enumerated type would be better here.
(not a strong opinion)

> +
> +static int fwu_get_dev_mdata(struct udevice **dev, struct fwu_mdata *mdata)
> +

Remove this empty line.

> +{
> +       int ret;
> +
> +       ret = uclass_first_device(UCLASS_FWU_MDATA, dev);
> +       if (ret) {
> +               log_debug("Cannot find fwu device\n");
> +               return ret;
> +       }

`uclass_first_device()` returns 0 when node is not found but no issue
reported while parsing the FDT (learned by experience :(. In that
case, *dev is set to NULL and next instruction segfaults.
Proposal:

     ret = uclass_first_device(UCLASS_FWU_MDATA, dev);
-    if (ret) {
+    if (ret || !*dev) {
         log_debug("Cannot find fwu device\n");
+        if (!ret)
+            ret = -ENOENT;
         return ret;
     }



> +
> +       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_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 < 0) {

Function description says it returns 0 on success so prefer here '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;
> +       u32 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 < 0) {

Same comment here: error case should be trapped with 'if (ret)'.

br,
etienne

> +               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);
> +}
> --
> 2.34.1
>

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