Re: [PATCH RFC 2/6] arm64: dts: qcom: ipq5424: Add the IMEM node

[Konrad Dybcio]

On 4/11/25 7:01 AM, Kathiravan Thirumoorthy wrote:
> 
> On 4/10/2025 12:11 AM, Konrad Dybcio wrote:
>> On 4/8/25 10:49 AM, Kathiravan Thirumoorthy wrote:
>>> Add the IMEM node to the device tree to extract debugging information
>>> like system restart reason, which is populated via IMEM. Define the
>>> IMEM region to enable this functionality. Corresponding DTS and driver
>>> changes will be added incrementally.
>>>
>>> Signed-off-by: Kathiravan Thirumoorthy <kathiravan.thirumoorthy@xxxxxxxxxxxxxxxx>
>>> ---
>>>   arch/arm64/boot/dts/qcom/ipq5424.dtsi | 9 +++++++++
>>>   1 file changed, 9 insertions(+)
>>>
>>> diff --git a/arch/arm64/boot/dts/qcom/ipq5424.dtsi b/arch/arm64/boot/dts/qcom/ipq5424.dtsi
>>> index 5d6ed2172b1bb0a57c593f121f387ec917f42419..a772736f314f46d11c473160c522af4edeb900b7 100644
>>> --- a/arch/arm64/boot/dts/qcom/ipq5424.dtsi
>>> +++ b/arch/arm64/boot/dts/qcom/ipq5424.dtsi
>>> @@ -486,6 +486,15 @@ ssphy_0: phy@7d000 {
>>>               status = "disabled";
>>>           };
>>>   +        sram@8600000 {
>>> +            compatible = "qcom,ipq5424-imem", "syscon", "simple-mfd";
>>> +            reg = <0 0x08600000 0 0x1000>;
>>> +            ranges = <0 0 0x08600000 0x1000>;
>> It looks like this should be a little longer
> 
> 
> Yes. It is 112KB. But only first 4KB is accessible by all masters in the system, remaining regions are access protected by TZ. I shall mention this in the commit message in the next version.

I think we should describe the full length of it - it's only if we
add a subnode that we actually access it

Konrad