Re: [PATCH v8 01/18] media: iris: Add Gen2 firmware autodetect and fallback

[Bryan O'Donoghue <bod@kernel.org>]

On 30/07/2026 16:20, Dmitry Baryshkov wrote:
> From: Dikshita Agarwal<dikshita.agarwal@oss.qualcomm.com>
> 
> Some Iris platforms support both Gen1 and Gen2 HFI firmware images.
> Update the firmware loading logic to handle this generically by
> preferring Gen2 when available, while safely falling back to Gen1
> when required.
> 
> The firmware loading logic is updated with the following priority:
> 1. Device Tree (`firmware-name`): If specified, load unconditionally.
> 2. Gen2 default : If no DT override exists, select the Gen2 firmware
>     descriptor when present and attempt to load the corresponding
>     firmware image.
> 3. Gen1 Fallback: If loading the Gen2 firmware fails and a Gen1
>     descriptor is available, retry with the Gen1 firmware image.
> 
> Loading and generation detection are split into two steps.
> iris_load_firmware() applies the priority above and returns the loaded
> image together with a candidate descriptor. iris_detect_firmware() then
> runs only after qcom_mdt_load() has succeeded and publishes the chosen
> descriptor, so the driver commits to a HFI generation only for an image
> that has actually been loaded.
> 
> When a platform provides both Gen1 and Gen2 firmware descriptors and the
> firmware is loaded via a DT override, the candidate descriptor is only a
> default: iris_detect_firmware() inspects the loaded image to pick the
> generation, before authentication. It scans the memory populated by
> qcom_mdt_load() rather than the request_firmware() blob, so that a split
> .mdt image, whose version string lives in the .bNN data segments and not
> in the ELF headers, is classified correctly. The firmware is classified
> as Gen2 if the QC_IMAGE_VERSION_STRING starts with "vfw" or matches the
> "video-firmware.N.M" format with N >= 2.
> 
> If a Gen1 firmware image is detected in this case, the driver switches
> to the Gen1 firmware descriptor and associated platform data so that
> the correct HFI implementation is used.
> 
> This change makes firmware generation detection platform‑agnostic,
> preserves DT overrides, prefers newer Gen2 firmware when available,
> and maintains compatibility with platforms that only support Gen1.
> 
> Signed-off-by: Dikshita Agarwal<dikshita.agarwal@oss.qualcomm.com>
> Co-developed-by: Dmitry Baryshkov<dmitry.baryshkov@oss.qualcomm.com>
> Signed-off-by: Dmitry Baryshkov<dmitry.baryshkov@oss.qualcomm.com>

Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>