diff mbox series

[v10,06/15] FWU: Add helper functions for accessing FWU metadata

Message ID 20220915081451.633983-7-sughosh.ganu@linaro.org
State Superseded
Headers show
Series FWU: Add FWU Multi Bank Update feature support | expand

Commit Message

Sughosh Ganu Sept. 15, 2022, 8:14 a.m. UTC
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@linaro.org>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Acked-by: Etienne Carriere <etienne.carriere@linaro.org>
---
Changes since V9:
* Remove unneeded braces as suggested by Ilias

 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

Comments

Ilias Apalodimas Sept. 22, 2022, 8:59 a.m. UTC | #1
Hi Sughosh

On Thu, Sep 15, 2022 at 01:44:42PM +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@linaro.org>
> Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
> Acked-by: Etienne Carriere <etienne.carriere@linaro.org>
> ---
> Changes since V9:
> * Remove unneeded braces as suggested by Ilias
> 
>  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 1e16253f69..3ff37c628b 100644
> --- a/include/fwu.h
> +++ b/include/fwu.h
> @@ -215,4 +215,33 @@ 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 fb9dbca307..8e91b7aeae 100644
> --- a/lib/fwu_updates/fwu.c
> +++ b/lib/fwu_updates/fwu.c
> @@ -331,3 +331,30 @@ 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++;
> +
> +	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 get that we only currently support it on mmc, but the if above is not
going to scale as we add devices.  Is there something better we  can come
up with? Probably a helper in the dfu layer?

Cheers
/Ilias


> +		}
> +	}
> +
> +	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
>
Sughosh Ganu Sept. 22, 2022, 9:35 a.m. UTC | #2
hi Ilias,

On Thu, 22 Sept 2022 at 14:29, Ilias Apalodimas
<ilias.apalodimas@linaro.org> wrote:
>
> Hi Sughosh
>
> On Thu, Sep 15, 2022 at 01:44:42PM +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@linaro.org>
> > Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
> > Acked-by: Etienne Carriere <etienne.carriere@linaro.org>
> > ---
> > Changes since V9:
> > * Remove unneeded braces as suggested by Ilias
> >
> >  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 1e16253f69..3ff37c628b 100644
> > --- a/include/fwu.h
> > +++ b/include/fwu.h
> > @@ -215,4 +215,33 @@ 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 fb9dbca307..8e91b7aeae 100644
> > --- a/lib/fwu_updates/fwu.c
> > +++ b/lib/fwu_updates/fwu.c
> > @@ -331,3 +331,30 @@ 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++;
> > +
> > +     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 get that we only currently support it on mmc, but the if above is not
> going to scale as we add devices.  Is there something better we  can come
> up with? Probably a helper in the dfu layer?

Currently, the DFU supports only the mmc which will be a GPT
partitioned device. But yes, yours is a valid point in terms of
scalability. However, I am wondering if this check should instead be
in the board file. Every platform would know which is the device being
used for storing the firmware images. Will this check not be more apt
in a board function?

-sughosh

>
> Cheers
> /Ilias
>
>
> > +             }
> > +     }
> > +
> > +     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
> >
Ilias Apalodimas Sept. 23, 2022, 6:16 a.m. UTC | #3
[...]

> > > +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++;
> > > +
> > > +     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 get that we only currently support it on mmc, but the if above is not
> > going to scale as we add devices.  Is there something better we  can come
> > up with? Probably a helper in the dfu layer?
> 
> Currently, the DFU supports only the mmc which will be a GPT
> partitioned device. But yes, yours is a valid point in terms of
> scalability. However, I am wondering if this check should instead be
> in the board file. Every platform would know which is the device being
> used for storing the firmware images. Will this check not be more apt
> in a board function?

Isn't this supposed to come from the dfu_alt_info in the command line?
IOW What you are trying to prevent here is a user misconfiguration?

Thanks
/Ilias
> 
> -sughosh
> 
> >
> > Cheers
> > /Ilias
> >
> >
> > > +             }
> > > +     }
> > > +
> > > +     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
> > >
diff mbox series

Patch

diff --git a/include/fwu.h b/include/fwu.h
index 1e16253f69..3ff37c628b 100644
--- a/include/fwu.h
+++ b/include/fwu.h
@@ -215,4 +215,33 @@  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 fb9dbca307..8e91b7aeae 100644
--- a/lib/fwu_updates/fwu.c
+++ b/lib/fwu_updates/fwu.c
@@ -331,3 +331,30 @@  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++;
+
+	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;
+		}
+	}
+
+	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);
+}