Re: [PATCH v2 0/4] Qualcomm: expand capsule update support

[Sumit Garg <sumit.garg@kernel.org>]

On Fri, May 02, 2025 at 02:16:53PM +0200, Casey Connolly wrote:
> Hi Sumit,
> 
> On 5/2/25 12:50, Sumit Garg wrote:
> > Hi Casey
> > 
> > On Fri, Apr 11, 2025 at 05:03:33PM +0200, Caleb Connolly wrote:
> > > The initial capsule update support only worked on the RB3 Gen 2 and made
> > > a lot of assumptions specific to that board.
> > > 
> > > Implement the logic necessary to update U-Boot no matter where it was
> > > flashed to, independent of any particular board.
> > > 
> > > First, we keep track of how U-Boot was loaded, specifically if we had a
> > > valid external FDT (even if we didn't use it) this indicates that we
> > > were booted via the Android bootloader, in this case the target for
> > > capsule updates is the boot partition. Otherwise, we target the uefi
> > > partition (if it exists) or the xbl partition. We handle A/B support for
> > > all 3 (currently we always flash to the currently active partition with
> > > a minor exception for the uefi partition).
> > 
> > Does this means say if we are booting from "A" partition then the update
> > gets applied to "A" partition only? IOW, we don't support dual bank
> > updates as of now?
> 
> Yes exactly, to have A/B working we would need the following:
> 
> * Implement all the fiddly GPT stuff (the vendor bits but also swapping the
> partition type GUIDs between A/B partitions)
> * Change MMC/UFS boot block/LUN
> * Support flashing all other bootloader partitions via capsule update
> 
> And really some tooling to produce said capsule update files containing all
> the bootloader related images.

Thanks for the info, those can sure be next steps.

> 
> > 
> > > 
> > > We introduce two new fw_name strings to differentiate the GUIDs based on
> > > the target partition, this means one board can support multiple boot
> > > methods with capsule update support for all of them (typically this
> > > would be chainloading OR flashing U-Boot to XBL).
> > > 
> > > Lastly, the call to scsi_scan() in dfu_scsi.c is removed. Since
> > > scsi_scan() unbinds all scsi devices it breaks device handles maintained
> > > in the EFI layer for the duration of the capsule update process and
> > > causes the EFI filesystem access to delete the capsule file after the
> > > update to fail.
> > > 
> > > Boards should instead be responsible for calling scsi_scan() before
> > > initiating DFU.
> > 
> > Thanks for working on EFI firmware capsule updates feature. I think
> > currently we are missing any documentation from this patch-set. IOW, how
> > one can test updating U-Boot via EFI firmware capsules? I suppose we are
> > using here dynamic GUID generation while creating update capsules,
> > right?
> 
> Yes, we're using dynamic GUIDs. I have written a small tool and brief docs
> here for creating an LVFS cabinet which can be used with FWUPD
> 
> https://github.com/kcxt/mkcab

Thanks for working on that tooling. However, it would be better for
U-Boot documentation to instead use standard tooling like:

$ fwupdtool build-cabinet ARCHIVE FIRMWARE METAINFO

where we can provide an example meta info xml file in the docs for Qcom
platforms.

> 
> I'll write something in doc/board/qualcomm to explain things too (excluding
> the LVFS bits).

Thanks.

-Sumit

> 
> Kind regards,
> Casey (she/they)>
> > -Sumit
> > 
> > > 
> > > ---
> > > Changes in v2:
> > > - Restrict the partition hunt to either UFS storage or the first MMC
> > >    device so that we never accidentally write to some external storage
> > >    (like an sdcard) during a capsule update.
> > > - Fix typo
> > > - Link to v1: https://lore.kernel.org/r/20250326-b4-qcom-capsule-update-improvements-v1-0-afe2e3696675@linaro.org
> > > 
> > > ---
> > > Caleb Connolly (4):
> > >        mach-snapdragon: track boot source
> > >        mach-snapdragon: CapsuleUpdate: support all boot methods
> > >        dfu: scsi: don't call scsi_scan()
> > >        qcom_defconfig: enable capsule update support
> > > 
> > >   arch/arm/mach-snapdragon/board.c          |  26 +++
> > >   arch/arm/mach-snapdragon/capsule_update.c | 274 ++++++++++++++++++++++++------
> > >   arch/arm/mach-snapdragon/qcom-priv.h      |  14 ++
> > >   configs/qcm6490_defconfig                 |   6 -
> > >   configs/qcom_defconfig                    |   3 +
> > >   drivers/dfu/dfu_scsi.c                    |   5 -
> > >   6 files changed, 266 insertions(+), 62 deletions(-)
> > > ---
> > > base-commit: 885d68280c29b8011731b6a7cdac32b8d9a4e6fd
> > > change-id: 20250326-b4-qcom-capsule-update-improvements-16ff7bc2d1d2
> > > 
> > > Caleb Connolly <caleb.connolly@linaro.org>
> > > 
> 
> -- 
> Casey (she/they)
>