Re: [PATCH 2/2] media: iris: Enable Gen2 HFI on SC7280

[Dikshita Agarwal]

On 2/9/2026 6:05 PM, Dmitry Baryshkov wrote:
> On Mon, Feb 09, 2026 at 05:04:48PM +0530, Dikshita Agarwal wrote:
>>
>>
>> On 2/9/2026 3:32 PM, Konrad Dybcio wrote:
>>> On 2/9/26 10:45 AM, Dikshita Agarwal wrote:
>>>> SC7280 supports both Gen1 and Gen2 HFI firmware. The driver continues to
>>>> use Gen1 by default, but boards that intend to use Gen2 firmware can
>>>> opt‑in by specifying a Gen2 image through the Device Tree
>>>> 'firmware-name' property.
>>>>
>>>> Based on this property and the availability of the referenced
>>>> firmware binary, the driver selects the appropriate HFI generation and
>>>> updates its platform data accordingly. Boards that do not
>>>> specify a Gen2 firmware, or where the firmware is not present,
>>>> automatically fall back to Gen1.
>>>>
>>>> Signed-off-by: Dikshita Agarwal <dikshita.agarwal@xxxxxxxxxxxxxxxx>
>>>> ---
>>>
>>> [...]
>>>
>>>> +int iris_update_platform_data(struct iris_core *core)
>>>> +{
>>>> +	const char *fwname = NULL;
>>>> +	const struct firmware *fw;
>>>> +	int ret;
>>>> +
>>>> +	if (of_device_is_compatible(core->dev->of_node, "qcom,sc7280-venus")) {
>>>> +		ret = of_property_read_string_index(core->dev->of_node, "firmware-name", 0,
>>>> +					    &fwname);
>>>> +		if (ret)
>>>> +			return 0;
>>>> +
>>>> +		if (strstr(fwname, "gen2")) {
>>>> +			ret = request_firmware(&fw, fwname, core->dev);
>>>> +			if (ret) {
>>>> +				dev_err(core->dev, "Specified firmware is not present\n");
>>>> +				return ret;
>>>
>>> This is fragile - if someone names names their gen1 firmware something like
>>> "myproduct_gen2_vidfw.mbn", it's going to match..
>>>
>>> Could we instead do something like the explicit format checks in
>>> venus/hfi_msgs.c : sys_get_prop_image_version(), based on the **contents**
>>> of the binary?
>>>
>>
>> I agree that checking for "gen2" as a substring in the firmware name is not
>> reliable. Unfortunately, we cannot
>> usevenus/hfi_msgs.c:sys_get_prop_image_version() (or any Gen1 HFI query) to
>> probe the contents of the binary here, because Gen1 vs Gen2 have
>> incompatible HFI protocols—probing a Gen2 image with Gen1 HFI (or
>> vice‑versa) isn’t viable in this path.
> 
> Can't we perform Gen2 query on Gen1 firmware, get the error and act
> accordingly? Or, better, perform Gen1 query on Gen2 firmware, receive
> the error from the firmware and act? In the end, your team is handling
> the firmware. If you want to support both interfaces, it should be a
> runtime check rather than filename matching.
> 
>>
>> To avoid accidental matches, I can switch to an exact filename match
>> instead. That way, only the specific Gen2 image (for example
>> "qcom/vpu/vpu20_p1_gen2.mbn") will trigger the Gen2 path, and boards that
> 
> How do you detect that for the OEM-signed firmware, which can have
> random name?
> 
>> want to use Gen2 can opt in by naming the firmware accordingly.

I Explored on suggested alternative approaches and seeing some limitation
with the both of them:

1. Detecting Gen1/Gen2 by scanning the firmware blob (fw->data)
It is possible to parse QC_IMAGE_VERSION_STRING from the .mbn and  extract
the version string. The issues with this approach :

- the version string has no explicit marker that identifies Gen1 vs Gen2.

- This prefix is not a formal ABI, and it is not consistent across SoCs.
Each SoC family uses different naming patterns in the version string.

Example : For SC7280 Gen1 we currently see:
QC_IMAGE_VERSION_STRING=video-firmware.1.0-<hash> while SM8250 has
QC_IMAGE_VERSION_STRING=VIDEO.VPU.1.0-00119-<>

So the driver would need SoC‑specific string‑matching rules, which is hard
to maintain if we are looking for a design to address all available SOCs.
	
2. Booting the firmware and querying it via an HFI system property
Issues with this approach :

- Gen1 and Gen2 use different HFI protocol formats (different packet
layouts, IDs, and message structures). There is no unified HFI message that
both generations can safely accept.

- The HFI protocol provides no version marker in any packet header.
The firmware does not know whether it is being talked to with Gen1‑style
packets or Gen2‑style packets. The driver simply typecasts the memory
buffer into a Gen1 or Gen2 packet type — the firmware has no concept of
“wrong HFI generation”. So it cannot return a dedicated error indicating
“incompatible HFI interface”.


Thanks,
Dikshita

>>
>> Thanks,
>> Dikshita
>>
>>> Konrad
>