[PATCH v11 06/15] FWU: Add helper functions for accessing FWU metadata

[Ilias Apalodimas]

On Wed, Sep 28, 2022 at 02:59:47PM +0530, Sughosh Ganu wrote:
> Add weak functions for getting the update index value and dfu
> alternate number needed for FWU Multi Bank update
> functionality.
> 
> The current implementation for getting the update index value is for
> platforms with 2 banks. If a platform supports more than 2 banks, it
> can implement it's own function. The function to get the dfu alternate
> number has been added for platforms with GPT partitioned storage
> devices. Platforms with other storage partition scheme need to
> implement their own function.
> 
> Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
> Reviewed-by: Patrick Delaunay <patrick.delaunay at foss.st.com>
> Acked-by: Etienne Carriere <etienne.carriere at linaro.org>
> ---
> Changes since V10: None
> 
> Note: I have not changed the logic of the check in
> fwu_gpt_get_alt_num(). This can be extended if and when another GPT
> based device gets added to the DFU framework.
> 
>  include/fwu.h             |  29 ++++++++++
>  lib/fwu_updates/fwu.c     |  27 +++++++++
>  lib/fwu_updates/fwu_gpt.c | 114 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 170 insertions(+)
>  create mode 100644 lib/fwu_updates/fwu_gpt.c
> 
> diff --git a/include/fwu.h b/include/fwu.h
> index 167f91388e..99f43f07b0 100644
> --- a/include/fwu.h
> +++ b/include/fwu.h
> @@ -212,4 +212,33 @@ int fwu_accept_image(efi_guid_t *img_type_id, u32 bank);
>   */
>  int fwu_clear_accept_image(efi_guid_t *img_type_id, u32 bank);
>  
> +/**
> + * fwu_plat_get_alt_num() - Get the DFU Alt Num for the image from the platform
> + * @dev: FWU device
> + * @image_guid: Image GUID for which DFU alt number needs to be retrieved
> + * @alt_num: Pointer to the alt_num
> + *
> + * Get the DFU alt number from the platform for the image specified by the
> + * image GUID.
> + *
> + * Return: 0 if OK, -ve on error
> + *
> + */
> +int fwu_plat_get_alt_num(struct udevice *dev, efi_guid_t *image_guid,
> +			 u8 *alt_num);
> +
> +/**
> + * fwu_plat_get_update_index() - Get the value of the update bank
> + * @update_idx: Bank number to which images are to be updated
> + *
> + * Get the value of the bank(partition) to which the update needs to be
> + * made.
> + *
> + * Note: This is a weak function and platforms can override this with
> + * their own implementation for selection of the update bank.
> + *
> + * Return: 0 if OK, -ve on error
> + *
> + */
> +int fwu_plat_get_update_index(uint *update_idx);
>  #endif /* _FWU_H_ */
> diff --git a/lib/fwu_updates/fwu.c b/lib/fwu_updates/fwu.c
> index fe8058bc37..5cf6bec6a0 100644
> --- a/lib/fwu_updates/fwu.c
> +++ b/lib/fwu_updates/fwu.c
> @@ -361,3 +361,30 @@ 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);
>  }
> +
> +/**
> + * fwu_plat_get_update_index() - Get the value of the update bank
> + * @update_idx: Bank number to which images are to be updated
> + *
> + * Get the value of the bank(partition) to which the update needs to be
> + * made.
> + *
> + * Note: This is a weak function and platforms can override this with
> + * their own implementation for selection of the update bank.
> + *
> + * Return: 0 if OK, -ve on error
> + *
> + */
> +__weak int fwu_plat_get_update_index(uint *update_idx)
> +{
> +	int ret;
> +	u32 active_idx;
> +
> +	ret = fwu_get_active_index(&active_idx);
> +	if (ret < 0)
> +		return -1;
> +
> +	*update_idx = (active_idx + 1) % CONFIG_FWU_NUM_BANKS;
> +
> +	return ret;
> +}
> diff --git a/lib/fwu_updates/fwu_gpt.c b/lib/fwu_updates/fwu_gpt.c
> new file mode 100644
> index 0000000000..a1b0f3bea7
> --- /dev/null
> +++ b/lib/fwu_updates/fwu_gpt.c
> @@ -0,0 +1,114 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2022, Linaro Limited
> + */
> +
> +#include <blk.h>
> +#include <dfu.h>
> +#include <efi.h>
> +#include <efi_loader.h>
> +#include <fwu.h>
> +#include <log.h>
> +#include <part.h>
> +
> +#include <linux/errno.h>
> +
> +static int get_gpt_dfu_identifier(struct blk_desc *desc, efi_guid_t *image_guid)
> +{
> +	int i;
> +	struct disk_partition info;
> +	efi_guid_t unique_part_guid;
> +
> +	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))
> +			return i;
> +	}
> +
> +	log_err("No partition found with image_guid %pUs\n", image_guid);
> +	return -ENOENT;
> +}
> +
> +static int fwu_gpt_get_alt_num(struct blk_desc *desc, efi_guid_t *image_guid,
> +			       u8 *alt_num, unsigned char dfu_dev)
> +{
> +	int ret = -1;
> +	int i, part, dev_num;
> +	int nalt;
> +	struct dfu_entity *dfu;
> +
> +	dev_num = desc->devnum;
> +	part = get_gpt_dfu_identifier(desc, image_guid);
> +	if (part < 0)
> +		return -ENOENT;
> +
> +	dfu_init_env_entities(NULL, NULL);
> +
> +	nalt = 0;
> +	list_for_each_entry(dfu, &dfu_list, list)
> +		nalt++;

Why do we have to do this?  Can't we just call dfu_get_entity() on a
for(;;) loop and break out if the result is NULL?

> +
> +	if (!nalt) {
> +		log_warning("No entities in dfu_alt_info\n");
> +		dfu_free_entities();
> +		return -ENOENT;
> +	}
> +
> +	for (i = 0; i < nalt; i++) {
> +		dfu = dfu_get_entity(i);
> +
> +		if (!dfu)
> +			continue;
> +
> +		/*
> +		 * Currently, Multi Bank update
> +		 * feature is being supported
> +		 * only on GPT partitioned
> +		 * MMC/SD devices.
> +		 */
> +		if (dfu->dev_type != dfu_dev)
> +			continue;
> +
> +		if (dfu->layout == DFU_RAW_ADDR &&
> +		    dfu->data.mmc.dev_num == dev_num &&
> +		    dfu->data.mmc.part == part) {
> +			*alt_num = dfu->alt;
> +			ret = 0;
> +			break;
> +		}

I still this needs to go into a different function.  Maybe in one with 
switch/cases where you only check DFU_DEV_MMC for now and return -ENOTSUPP
for other device types

> +	}
> +
> +	dfu_free_entities();
> +
> +	return ret;
> +}
> +
> +/**
> + * fwu_plat_get_alt_num() - Get the DFU alt number
> + * @dev: FWU metadata device
> + * @image_guid: GUID value of the image for which the alt num is to
> + *              be obtained
> + * @alt_num: The DFU alt number for the image that is to be updated
> + *
> + * Get the DFU alt number for the image that is to be updated. The
> + * image is identified with the image_guid parameter that is passed
> + * to the function.
> + *
> + * Note: This is a weak function and platforms can override this with
> + * their own implementation for obtaining the alt number value.
> + *
> + * Return: 0 if OK, -ve on error
> + *
> + */
> +__weak int fwu_plat_get_alt_num(struct udevice *dev, efi_guid_t *image_guid,
> +				u8 *alt_num)
> +{
> +	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
> +
> +	return fwu_gpt_get_alt_num(dev_get_uclass_plat(priv->blk_dev),
> +				   image_guid, alt_num, DFU_DEV_MMC);
> +}
> -- 
> 2.34.1
> 

Cheers
/Ilias