Re: [PATCH] arm64: dts: qcom: sc7280: Mark FastRPC context banks as dma-coherent

[Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>]

On 21/05/2025 17:08, Xilin Wu wrote:
> On 2025/5/21 05:34:08, Dmitry Baryshkov wrote:
>> On Wed, Apr 16, 2025 at 06:54:18PM +0800, Xilin Wu wrote:
>>> The FastRPC context banks are DMA-coherent on sc7280 platform. Mark them
>>> as such.
>>>
>>> This allows LLM inferencing on the CDSP using Qualcomm AI Engine Direct
>>> SDK on the qcs6490 platform.
>>>
>>> Signed-off-by: Xilin Wu <sophon@radxa.com>
>>> ---
>>>   arch/arm64/boot/dts/qcom/sc7280.dtsi | 15 +++++++++++++++
>>>   1 file changed, 15 insertions(+)
>>
>> Are context banks coherent on FP5? On Herobrine? Or Nothing Phone?
>>
> 
> Hi,
> 
> This was tested on an upcoming SBC (Radxa Dragon Q6A) with the Qualcomm 
> Linux cdsp firmware. There would be an error in the LLM demo app without 
> this patch.
> 
> I'm honestly not sure about the devices that you mentioned, since I 
> don't have any other sc7280 devices to test.

You have enabled dma-coherency for the several families of devices using 
SC7280, QCM/QCS6490 and SM7350. Some of them might have older firmware, 
etc. We had this issue with SDM845 / RB3 boards.

Bjorn, do we need to revert this patch? See corresponding discussion at 
https://lore.kernel.org/linux-arm-msm/70ffec25-17c9-4424-9d0b-da6560f7160d@quicinc.com

-- 
With best wishes
Dmitry