[PATCH 2/4] mach-snapdragon: CapsuleUpdate: support all boot methods

[Ilias Apalodimas]

Hi Caleb

On Wed, 26 Mar 2025 at 19:41, Caleb Connolly <caleb.connolly at linaro.org> wrote:
>
> Expand capsule update support to correctly identify which partition
> U-Boot is flashed to (between xbl, uefi, and boot including A/B
> variants).
>
> Use qcom_boot_source to determine if we were chainloaded from ABL,
> meaning U-Boot is on the boot partition, otherwise we assume uefi if
> it's available, finally leaving the xbl partition.
>
> Set a different fw_name based on the target partition to prevent GUID
> collisions, since a board may support U-Boot flashed to boot or XBL we
> need to differentiate them since the U-Boot binary must be built
> differently.
>

[...]


> -               if (!strncmp(info.name, partname, strlen(partname))) {
> -                       log_debug("Found active %s partition: '%s'!\n", partname, info.name);
> -                       strlcpy(name, info.name, sizeof(info.name));
> -                       return partnum;
> +               desc = dev_get_uclass_plat(dev);
> +               if (!desc || desc->part_type == PART_TYPE_UNKNOWN)
> +                       continue;
> +               for (partnum = 1;; partnum++) {
> +                       ret = part_get_info(desc, partnum, &info);
> +                       if (ret)
> +                               break;
> +
> +                       slot_status = (struct part_slot_status *)&info.type_flags;
> +
> +                       /*
> +                        * Qualcomm Linux devices have a "uefi" partition, it's A/B but the
> +                        * flags might not be set so we assume the A partition unless the B
> +                        * partition is active.
> +                        */
> +                       if (!strncmp(info.name, "uefi", strlen("uefi")))

since it's a static string, use sizeof() to compute it at build time.
I get what you are trying to do here and automatically detect the boot
partition, I'll have a closer look in case we can somehow make this
loop shorter.

{
> +                               /*
> +                                * If U-Boot was chainloaded somehow we can't be flashed to
> +                                * the uefi partition
> +                                */
> +                               if (qcom_boot_source != QCOM_BOOT_SOURCE_XBL)
> +                                       continue;
> +
> +                               *target_part_type = TARGET_PART_UEFI;
> +                               /*
> +                                * Found an active UEFI partition, this is where U-Boot is
> +                                * flashed.
> +                                */
> +                               if (slot_status->active)
> +                                       goto found;
> +
> +                               /* Prefer A slot if it's not marked active */
> +                               if (get_part_slot(info.name) == SLOT_A) {

SLOT_NONE only applies to non-uefi partitions?

> +                                       /*
> +                                        * If we found the A slot after the B slot (both
> +                                        * inactive) then we assume U-Boot is on the A slot.
> +                                        */
> +                                       if (uefi_partnum >= 0)
> +                                               goto found;
> +
> +                                       /* Didn't find the B slot yet */
> +                                       uefi_partnum = partnum;
> +                                       strlcpy(ptn_name, info.name, 32);

sizeof(ptn_name)

> +                               } else {
> +                                       /*
> +                                        * Found inactive B slot after inactive A slot, return
> +                                        * the A slot
> +                                        */
> +                                       if (uefi_partnum >= 0) {
> +                                               partnum = uefi_partnum;
> +                                               goto found;
> +                                       }
> +
> +                                       /*
> +                                        * Didn't find the A slot yet. Record that we found the
> +                                        * B slot

[...]

Cheers
/Ilias