Re: [PATCH 3/4] arm64: dts: qcom: sdm630: describe adsp_mem region properly

Nickolay Goppen
2026-04-21T08:32:28Z

21.04.2026 11:29, Ekansh Gupta wrote:
> On 17-04-2026 20:45, Ekansh Gupta wrote:
>> On 15-04-2026 15:22, Konrad Dybcio wrote:
>>> On 4/15/26 11:40 AM, Nickolay Goppen wrote:
>>>> Downstream [1] this region is marked as shared and reusable so
>>>> describe it that way.
>>>>
>>>> [1]: https://github.com/xiaomi-sdm660/android_kernel_xiaomi_sdm660/blob/11-EAS/arch/arm/boot/dts/qcom/sdm660.dtsi#L448
>>>>
>>>> Signed-off-by: Nickolay Goppen <setotau@mainlining.org>
>>>> ---
>>> +Ekansh some insight, please?
>>>
>>> We're giving away that memory via qcom_scm_assign_mem() anyway
>>> and I would assume that making it not-"no-map" could introduce issues
>>> when the OS tries to access that region
>>>
>> With the current version and the upcoming planned enhancements, I don't
>> see any major benefits of making this as not-"no-map".
>>
>> With posted enhancements[1], the plan is to qcom_scm_assign_mem() the
>> entire memory-region to lpass VMIDs. and un-assign it only during
>> fastrpc_rpmsg_remove(). There have been implementation in downstream
>> where this memory is dumped in case of SSR or audio PDR using minidump,
>> so marking it `reusable` might make sense there, but that dump logic is
>> not added upstream.
>>
>> Upon checking the DT, I see a bigger problem here, this memory-region
>> looks to me unused, it's not added under fastrpc adsp node(ref. [2]).
>> Please correct me if I am wrong about this point.
>>
>> [1]
>> https://lore.kernel.org/all/20260409062617.1182-1-jianping.li@oss.qualcomm.com/
>> [2]
>> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/arch/arm64/boot/dts/qcom/lemans.dtsi#n7500
> Just had a new finding on this. There is one more reason why it is not
> added as no-map in downstream. This audio PD carve-out region is not
> defined for most of the platform's memory-map.
>
> With a change to qcom_scm the memory during boot-up, issue was observed
> on RB3Gen2[1], where EFI firmware was loaded in the memory region which
> was causing boot-up issues.
>
> So defining it as no-map might not be correct and it might need be
> changed for all DT files.
So It needs to be set as not-"no-map"?
> I don't have a history of why it was added as a "no-map" region on
> upstream but looks like same has been followed for almost all the
> platforms. This needs to be modified based on the memory-maps and the
> region needs to allocate memory in a dynamic manner.
>
> [1] https://github.com/qualcomm-linux/kernel/pull/487
>
> //Ekansh
>> //Ekansh
>>> Konrad
>>>
>>>
>>>> arch/arm64/boot/dts/qcom/sdm630.dtsi | 3 ++-
>>>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/arch/arm64/boot/dts/qcom/sdm630.dtsi b/arch/arm64/boot/dts/qcom/sdm630.dtsi
>>>> index 4b47efdb57b2..13094b5e9339 100644
>>>> --- a/arch/arm64/boot/dts/qcom/sdm630.dtsi
>>>> +++ b/arch/arm64/boot/dts/qcom/sdm630.dtsi
>>>> @@ -495,8 +495,9 @@ venus_region: venus@9f800000 {
>>>> };
>>>>
>>>> adsp_mem: adsp-region@f6000000 {
>>>> + compatible = "shared-dma-pool";
>>>> reg = <0x0 0xf6000000 0x0 0x800000>;
>>>> - no-map;
>>>> + reusable;
>>>> };
>>>>
>>>> qseecom_mem: qseecom-region@f6800000 {
>>>>
--
Best regards,
Nickolay