[PATCH v2 1/4] disk: Add partition lookup by type GUID functionality

[Simon Glass]

Hi Balaji,

On Fri, 9 Jan 2026 at 00:09, Balaji Selvanathan
<balaji.selvanathan at oss.qualcomm.com> wrote:
>
> Introduce part_get_info_by_type_guid() function to enable partition
> lookup using partition type GUID. This complements the existing UUID
> lookup functionality and provides more flexible partition discovery
> mechanisms.
>
> Signed-off-by: Balaji Selvanathan <balaji.selvanathan at oss.qualcomm.com>
> ---
> Changes in v2:
> - No changes
>
>  disk/part.c    | 39 +++++++++++++++++++++++++++++++++++++++
>  include/part.h | 21 +++++++++++++++++++++
>  2 files changed, 60 insertions(+)

Do you feel able to write a test for this? There is a ChromeOS image
(mmc5.img) which has a lot of GUIDs in it.

root = oftree_root(oftree_default());
node = ofnode_find_subnode(root, "mmc5");
ut_assert(ofnode_valid(node));
ut_assertok(lists_bind_fdt(gd->dm_root, node, &dev, NULL, false));

Then something like:

struct udevice *dev, blk;
ut_assertok(uclass_get_device_by_seq(UCLASS_MMC, &dev))
ut_assertok(blk_get_from_parent(dev, &blk));

// it would be better if your function took a struct udevice *, but
that conversion has not been completed for other functions yet, so up
to you...

struct blk_desc *desc = mmc_get_blk_desc(struct mmc *mmc)

>
> diff --git a/disk/part.c b/disk/part.c
> index 49a0fca6b89..2bc21dd66cc 100644
> --- a/disk/part.c
> +++ b/disk/part.c
> @@ -731,6 +731,45 @@ int part_get_info_by_uuid(struct blk_desc *desc, const char *uuid,
>         return -ENOENT;
>  }
>
> +int part_get_info_by_type_guid(struct blk_desc *desc, const char *type_guid,
> +                              struct disk_partition *info)
> +{
> +       struct part_driver *part_drv;
> +       int ret;
> +       int i;
> +
> +       if (!IS_ENABLED(CONFIG_PARTITION_TYPE_GUID))
> +               return -ENOENT;
> +
> +       part_drv = part_driver_lookup_type(desc);
> +       if (!part_drv)
> +               return -1;

-ENOENT ? We should not return -PERM in an open-coded way

> +
> +       if (!part_drv->get_info) {
> +               log_debug("## Driver %s does not have the get_info() method\n",
> +                         part_drv->name);
> +               return -ENOSYS;
> +       }
> +
> +       for (i = 1; i < part_drv->max_entries; i++) {
> +               ret = part_drv->get_info(desc, i, info);
> +               if (ret != 0) {

if (ret)

> +                       /*
> +                        * Partition with this index can't be obtained, but
> +                        * further partitions might be, so keep checking.
> +                        */
> +                       continue;
> +               }
> +
> +               if (!strncasecmp(type_guid, disk_partition_type_guid(info), UUID_STR_LEN)) {

long line?

> +                       /* matched */
> +                       return i;
> +               }
> +       }
> +
> +       return -ENOENT;
> +}
> +
>  /**
>   * Get partition info from device number and partition name.
>   *
> diff --git a/include/part.h b/include/part.h
> index daebbbc2e68..85457618cdf 100644
> --- a/include/part.h
> +++ b/include/part.h
> @@ -327,6 +327,20 @@ int part_get_info_by_name(struct blk_desc *desc, const char *name,
>  int part_get_info_by_uuid(struct blk_desc *desc, const char *uuid,
>                           struct disk_partition *info);
>
> +/**
> + * part_get_info_by_type_guid() - Search for a partition by type GUID
> + *                                among all available registered partitions
> + *
> + * @desc:      block device descriptor
> + * @type_guid: the specified partition type GUID
> + * @info:      the disk partition info
> + *
> + * Return: the partition number on match (starting on 1), -ENOENT on no match,
> + * otherwise error
> + */
> +int part_get_info_by_type_guid(struct blk_desc *desc, const char *type_guid,
> +                              struct disk_partition *info);
> +
>  /**
>   * part_get_info_by_dev_and_name_or_num() - Get partition info from dev number
>   *                                         and part name, or dev number and
> @@ -404,6 +418,13 @@ static inline int part_get_info_by_uuid(struct blk_desc *desc, const char *uuid,
>         return -ENOENT;
>  }
>
> +static inline int part_get_info_by_type_guid(struct blk_desc *desc,
> +                                            const char *type_guid,
> +                                            struct disk_partition *info)
> +{
> +       return -ENOENT;
> +}
> +
>  static inline int
>  part_get_info_by_dev_and_name_or_num(const char *dev_iface,
>                                      const char *dev_part_str,
> --
> 2.34.1
>

Regards,
Simon