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

[Dikshita Agarwal]

On 2/17/2026 5:50 PM, Konrad Dybcio wrote:
> On 2/17/26 8:40 AM, Dikshita Agarwal wrote:
>>
>>
>> On 2/13/2026 5:34 PM, Dmitry Baryshkov wrote:
>>> On Thu, Feb 12, 2026 at 06:35:19PM +0530, Dikshita Agarwal wrote:
>>>>
>>>>
>>>> On 2/12/2026 5:13 PM, Konrad Dybcio wrote:
>>>>> On 2/12/26 12:16 PM, Dikshita Agarwal wrote:
>>>>>>
>>>>>>
>>>>>> 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>
>>>>>>>>>> ---
>>>>>
>>>>> [...]
>>>>>
>>>>>>>> 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.
>>>>>
>>>>> The only SoC with such distinction today is kodiak. So we can simply check:
>>>>>
>>>>> if (kodiak && strstr(fw->data, "VIDEO.VPU.1.0.")
>>>>> 	hfi = gen2;
>>>>
>>>> Agree, this works for Kodiak. However, Dmitry was also referring to other
>>>> SoCs that may support both Gen1 and Gen2, and at the moment there isn’t a
>>>> generic way to handle that check.
>>>>
>>>> Also, please note that the Kodiak Gen1 firmware uses the string
>>>> video-firmware.1.0, whereas Gen2 uses VIDEO.VPU.3.4.
>>>
>>> This is not quite true. Kodiak Gen2 uses:
>>>
>>> $ strings /lib/firmware/qcom/vpu/vpu20_p1_gen2.mbn | grep VERSION_S
>>> QC_IMAGE_VERSION_STRING=video-firmware.2.4.2-d7a3d5386743efb16b828e08695bea7722cafadd
>>>
>>> A collection of versions quickly captured from what I have here (for
>>> different chips, but for the overall picture):
>>>
>>> HFI Gen1:
>>>
>>> [skipping prehistorical / museum data]
>>> VIDEO.VE.5.2-00023-PROD-2
>>> VIDEO.VE.5.4-00059-PROD-1
>>> VIDEO.VE.6.0-00055-PROD-1
>>> VIDEO.IR.1.0-00005-PROD-4
>>> VIDEO.VPU.1.0-00119-PROD-2
>>> video-firmware.1.0-6804c210603073037fb32640a3dd6a46fe04edd6
>>> video-firmware.1.0-7da9db401e417a006ef915d6c4323f00cdbcf40a
>>> video-firmware.1.0-ed457c183307eff1737608763ca0f23656c95b53
>>> video-firmware.1.1-84a8080bf84fa9ab15b353bf03bea6e548d89d2f
>>>
>>>
>>> HFI Gen2:
>>> vfw-0:rel0095-d1a9e7c4a274aa13e4136500d19262f87ef2c921
>>> vfw-3.1:rel0085-070fa3311d9ef968015fee7fea07198d7eb208a1
>>> vfw-3.1:rel0093-7925621ff52ecb7b1565341042c4e5ffd4fc76ce
>>> vfw-3.5:rel0040-1ded01d0e6dcaef08b8155fd5a02f5b57248d5ca
>>> vfw-4.0:rel0045-25b39e81446baf48716df98dd37099a2103d36ee
>>> video-firmware.2.4-48ec04082362ef1922fec5e20e22f7954b11d736
>>> video-firmware.2.4.2-d7a3d5386743efb16b828e08695bea7722cafadd
>>> video-firmware.3.1-e5aea20c64cb6df9a1c9be99e206053b36424939
>>> video-firmware.3.4-e299f99ffcd086b43a2ccc7c3279ce5df404d693
>>>
>>> It seems we can assume that Gen2 is:
>>> - vfw-0
>>> - vfw-N.M
>>> - video-firmware.N.M where N >= 2
>>>
>>> All other binaries are Gen1.
>>>
>>> Also, we don't even have to query the binary firmware blob.
>>> After the firmware is started, you can read the version string from
>>> smem, saving us from strstr over the firmware image.
>>
>> AFAIK the video/iris firmware doesn't populates its version string into
>> SMEM by default.
>>
>> On venus, the version string appears in SMEM only once the driver
>> explicitly writes it after receiving the version info from the firmware as
>> part of an HFI response.
>> https://elixir.bootlin.com/linux/v6.18-rc5/source/drivers/media/platform/qcom/venus/hfi_msgs.c#L289
>>
>>
>> Iris does not implement this SMEM population path today, and the firmware
>> itself does not publish its version into SMEM automatically. Because of
>> that, reading the version from SMEM is not currently possible for iris.
>>
>> Also, relying on HFI to retrieve the version is not viable for detection
>> because we cannot issue a protocol‑specific HFI command until we already
>> know which HFI generation (Gen1 or Gen2) the currently loaded firmware
>> supports.
>>
>> Due to these constraints, I think, the only possible way is to extract the
>> version from the firmware binary blob itself.
> 
> Looks like both gens use the same iris_hfi_queue_write() logic for issuing
> packets and they both use the largely common iris_hfi_queue_dbg_read() logic
> 
> So, knowing that e.g. HFI_CMD_SYS_INIT (0x10001) and HFI_CMD_INIT (0x01000001)
> seem not to conflict, we should be able to issue say a gen1 command and check
> if we get a timeout, no?

The two HFI generations do share some lower‑level queue infrastructure, but
the command formats and packet layouts for Gen1 and Gen2 differ.

Because of this, sending a Gen1 HFI_CMD_SYS_INIT into a Gen2 firmware (or
vice‑versa) is not safe. The firmware will interpret the buffer strictly
according to its own expected packet layout, and since there is no
protocol‑level version discriminator, it has no way to recognize that the
host used the wrong HFI format.

Additionally, using a timeout as a discriminator is unreliable. If we issue
a command and receive no response, we cannot differentiate whether it due
to using the wrong HFI generation, or due to a genuine sys_init failure.

So, I will proceed with implementing the solution based on reading the
firmware blob, extracting the version string, and switching between Gen1
and Gen2 HFI accordingly. This avoids protocol ambiguity and does not
require the firmware to support any additional detection mechanism.

Thanks,
Dikshita

> 
> Konrad