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.

As described, overall IMEM region is 112KB but only initial 4KB is
accessible by all masters in the SoC.

Signed-off-by: Kathiravan Thirumoorthy <kathiravan.thirumoorthy@oss.qualcomm.com>
---
Changes in v6:
	- move to mmio-sram and drop the Konrad's R-b tag
Changes in v5:
	- No changes
Changes in v4:
	- No changes
Changes in v3:
	- Picked up the R-b tag
Changes in v2:
	- Describe the entire IMEM region in the node
	- Explicitly call out that initial 4K only accessible by all
	  masters in the commit message
---
 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 eb393f3fd728f0b2fc8cd93c849f8c170d76e312..90790f99f0597b63801d4e07b9b72cd372ad46d4 100644
--- a/arch/arm64/boot/dts/qcom/ipq5424.dtsi
+++ b/arch/arm64/boot/dts/qcom/ipq5424.dtsi
@@ -697,6 +697,15 @@ ssphy_0: phy@7d000 {
 			status = "disabled";
 		};
 
+		sram@8600000 {
+			compatible = "qcom,ipq5424-imem", "mmio-sram";
+			reg = <0 0x08600000 0 0x1c000>;
+			ranges = <0 0 0x08600000 0x1c000>;
+
+			#address-cells = <1>;
+			#size-cells = <1>;
+		};
+
 		usb3: usb3@8a00000 {
 			compatible = "qcom,ipq5424-dwc3", "qcom,dwc3";
 			reg = <0 0x08af8800 0 0x400>;

-- 
2.34.1

On 1/30/26 11:44 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.
> 
> As described, overall IMEM region is 112KB but only initial 4KB is
> accessible by all masters in the SoC.
> 
> Signed-off-by: Kathiravan Thirumoorthy <kathiravan.thirumoorthy@oss.qualcomm.com>
> ---
> Changes in v6:
> 	- move to mmio-sram and drop the Konrad's R-b tag
> Changes in v5:
> 	- No changes
> Changes in v4:
> 	- No changes
> Changes in v3:
> 	- Picked up the R-b tag
> Changes in v2:
> 	- Describe the entire IMEM region in the node
> 	- Explicitly call out that initial 4K only accessible by all
> 	  masters in the commit message
> ---
>  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 eb393f3fd728f0b2fc8cd93c849f8c170d76e312..90790f99f0597b63801d4e07b9b72cd372ad46d4 100644
> --- a/arch/arm64/boot/dts/qcom/ipq5424.dtsi
> +++ b/arch/arm64/boot/dts/qcom/ipq5424.dtsi
> @@ -697,6 +697,15 @@ ssphy_0: phy@7d000 {
>  			status = "disabled";
>  		};
>  
> +		sram@8600000 {
> +			compatible = "qcom,ipq5424-imem", "mmio-sram";
> +			reg = <0 0x08600000 0 0x1c000>;
> +			ranges = <0 0 0x08600000 0x1c000>;
> +
> +			#address-cells = <1>;
> +			#size-cells = <1>;

I think you may need to add 'no-memory-wc' too, in case someone uses
any of the sram functions on this in the future

Konrad

On 2/2/2026 5:53 PM, Konrad Dybcio wrote:
> On 1/30/26 11:44 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.
>>
>> As described, overall IMEM region is 112KB but only initial 4KB is
>> accessible by all masters in the SoC.
>>
>> Signed-off-by: Kathiravan Thirumoorthy <kathiravan.thirumoorthy@oss.qualcomm.com>
>> ---
>> Changes in v6:
>> 	- move to mmio-sram and drop the Konrad's R-b tag
>> Changes in v5:
>> 	- No changes
>> Changes in v4:
>> 	- No changes
>> Changes in v3:
>> 	- Picked up the R-b tag
>> Changes in v2:
>> 	- Describe the entire IMEM region in the node
>> 	- Explicitly call out that initial 4K only accessible by all
>> 	  masters in the commit message
>> ---
>>   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 eb393f3fd728f0b2fc8cd93c849f8c170d76e312..90790f99f0597b63801d4e07b9b72cd372ad46d4 100644
>> --- a/arch/arm64/boot/dts/qcom/ipq5424.dtsi
>> +++ b/arch/arm64/boot/dts/qcom/ipq5424.dtsi
>> @@ -697,6 +697,15 @@ ssphy_0: phy@7d000 {
>>   			status = "disabled";
>>   		};
>>   
>> +		sram@8600000 {
>> +			compatible = "qcom,ipq5424-imem", "mmio-sram";
>> +			reg = <0 0x08600000 0 0x1c000>;
>> +			ranges = <0 0 0x08600000 0x1c000>;
>> +
>> +			#address-cells = <1>;
>> +			#size-cells = <1>;
> I think you may need to add 'no-memory-wc' too, in case someone uses
> any of the sram functions on this in the future
Ack. Let me take care of this in next spin.
>
> Konrad

On Fri, Jan 30, 2026 at 04:14:31PM +0530, 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.
> 
> As described, overall IMEM region is 112KB but only initial 4KB is
> accessible by all masters in the SoC.
> 
> Signed-off-by: Kathiravan Thirumoorthy <kathiravan.thirumoorthy@oss.qualcomm.com>
> ---
> Changes in v6:
> 	- move to mmio-sram and drop the Konrad's R-b tag
> Changes in v5:
> 	- No changes
> Changes in v4:
> 	- No changes
> Changes in v3:
> 	- Picked up the R-b tag
> Changes in v2:
> 	- Describe the entire IMEM region in the node
> 	- Explicitly call out that initial 4K only accessible by all
> 	  masters in the commit message
> ---
>  arch/arm64/boot/dts/qcom/ipq5424.dtsi | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>


-- 
With best wishes
Dmitry