[PATCH] arm64: dts: exynos850: Add SRAM node

[PATCH] arm64: dts: exynos850: Add SRAM node

[Alexey Klimov]

SRAM is used by the ACPM protocol to retrieve the ACPM channels
information and configuration data. Add the SRAM node.

Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org>
---
 arch/arm64/boot/dts/exynos/exynos850.dtsi | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/arm64/boot/dts/exynos/exynos850.dtsi b/arch/arm64/boot/dts/exynos/exynos850.dtsi
index cb55015c8dce..cf4a6168846c 100644
--- a/arch/arm64/boot/dts/exynos/exynos850.dtsi
+++ b/arch/arm64/boot/dts/exynos/exynos850.dtsi
@@ -910,6 +910,14 @@ spi_2: spi@11d20000 {
 			};
 		};
 	};
+
+	apm_sram: sram@2039000 {
+		compatible = "mmio-sram";
+		reg = <0x0 0x2039000 0x40000>;
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges = <0x0 0x0 0x2039000 0x40000>;
+	};
 };
 
 #include "exynos850-pinctrl.dtsi"

---
base-commit: 66672af7a095d89f082c5327f3b15bc2f93d558e
change-id: 20260413-exynos850_sram-ca1200b99e82

Best regards,
-- 
Alexey Klimov <alexey.klimov@linaro.org>

Re: [PATCH] arm64: dts: exynos850: Add SRAM node

[Krzysztof Kozlowski]

On 13/04/2026 16:52, Alexey Klimov wrote:
> SRAM is used by the ACPM protocol to retrieve the ACPM channels
> information and configuration data. Add the SRAM node.
> 
> Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org>
> ---
>  arch/arm64/boot/dts/exynos/exynos850.dtsi | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/exynos/exynos850.dtsi b/arch/arm64/boot/dts/exynos/exynos850.dtsi
> index cb55015c8dce..cf4a6168846c 100644
> --- a/arch/arm64/boot/dts/exynos/exynos850.dtsi
> +++ b/arch/arm64/boot/dts/exynos/exynos850.dtsi
> @@ -910,6 +910,14 @@ spi_2: spi@11d20000 {
>  			};
>  		};
>  	};
> +
> +	apm_sram: sram@2039000 {
> +		compatible = "mmio-sram";
> +		reg = <0x0 0x2039000 0x40000>;
> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +		ranges = <0x0 0x0 0x2039000 0x40000>;

You miss here children.

Also, 'ranges' should be after 'reg'.

Best regards,
Krzysztof

Re: [PATCH] arm64: dts: exynos850: Add SRAM node

[Alexey Klimov]

On Mon Apr 13, 2026 at 4:23 PM BST, Krzysztof Kozlowski wrote:
> On 13/04/2026 16:52, Alexey Klimov wrote:
>> SRAM is used by the ACPM protocol to retrieve the ACPM channels
>> information and configuration data. Add the SRAM node.
>> 
>> Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org>
>> ---
>>  arch/arm64/boot/dts/exynos/exynos850.dtsi | 8 ++++++++
>>  1 file changed, 8 insertions(+)
>> 
>> diff --git a/arch/arm64/boot/dts/exynos/exynos850.dtsi b/arch/arm64/boot/dts/exynos/exynos850.dtsi
>> index cb55015c8dce..cf4a6168846c 100644
>> --- a/arch/arm64/boot/dts/exynos/exynos850.dtsi
>> +++ b/arch/arm64/boot/dts/exynos/exynos850.dtsi
>> @@ -910,6 +910,14 @@ spi_2: spi@11d20000 {
>>  			};
>>  		};
>>  	};
>> +
>> +	apm_sram: sram@2039000 {
>> +		compatible = "mmio-sram";
>> +		reg = <0x0 0x2039000 0x40000>;
>> +		#address-cells = <1>;
>> +		#size-cells = <1>;
>> +		ranges = <0x0 0x0 0x2039000 0x40000>;
>
> You miss here children.

Thank you! I guess I should convert it to smth like this:

apm_sram: sram@2039000 {
		compatible = "mmio-sram";
		reg = <0x0 0x2039000 0x40000>;
		ranges = <0x0 0x0 0x2039000 0x40000>;
		#address-cells = <1>;
		#size-cells = <1>;

		acpm_sram_region: sram-section@0 {
			reg = <0x0 0x40000>;
		};
	};

And then later reference shmem = &acpm_sram_region from acpm node.

> Also, 'ranges' should be after 'reg'.

Thanks, will fix this.

FWIW this commit is a copy of commit 48e7821b26904
https://lore.kernel.org/r/20250207-gs101-acpm-dt-v4-1-230ba8663a2d@linaro.org

Best regards,
Alexey

Re: [PATCH] arm64: dts: exynos850: Add SRAM node

[Krzysztof Kozlowski]

On 14/04/2026 11:00, Alexey Klimov wrote:
> On Mon Apr 13, 2026 at 4:23 PM BST, Krzysztof Kozlowski wrote:
>> On 13/04/2026 16:52, Alexey Klimov wrote:
>>> SRAM is used by the ACPM protocol to retrieve the ACPM channels
>>> information and configuration data. Add the SRAM node.
>>>
>>> Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org>
>>> ---
>>>  arch/arm64/boot/dts/exynos/exynos850.dtsi | 8 ++++++++
>>>  1 file changed, 8 insertions(+)
>>>
>>> diff --git a/arch/arm64/boot/dts/exynos/exynos850.dtsi b/arch/arm64/boot/dts/exynos/exynos850.dtsi
>>> index cb55015c8dce..cf4a6168846c 100644
>>> --- a/arch/arm64/boot/dts/exynos/exynos850.dtsi
>>> +++ b/arch/arm64/boot/dts/exynos/exynos850.dtsi
>>> @@ -910,6 +910,14 @@ spi_2: spi@11d20000 {
>>>  			};
>>>  		};
>>>  	};
>>> +
>>> +	apm_sram: sram@2039000 {
>>> +		compatible = "mmio-sram";
>>> +		reg = <0x0 0x2039000 0x40000>;
>>> +		#address-cells = <1>;
>>> +		#size-cells = <1>;
>>> +		ranges = <0x0 0x0 0x2039000 0x40000>;
>>
>> You miss here children.
> 
> Thank you! I guess I should convert it to smth like this:
> 
> apm_sram: sram@2039000 {
> 		compatible = "mmio-sram";
> 		reg = <0x0 0x2039000 0x40000>;
> 		ranges = <0x0 0x0 0x2039000 0x40000>;
> 		#address-cells = <1>;
> 		#size-cells = <1>;
> 
> 		acpm_sram_region: sram-section@0 {
> 			reg = <0x0 0x40000>;

This covers entire block, so feels pointless. Maybe requirement of
children should be dropped. What's the point of having children? Why
does the driver need them?

> 		};
> 	};
> 
> And then later reference shmem = &acpm_sram_region from acpm node.
> 
>> Also, 'ranges' should be after 'reg'.
> 
> Thanks, will fix this.
> 
> FWIW this commit is a copy of commit 48e7821b26904
> https://lore.kernel.org/r/20250207-gs101-acpm-dt-v4-1-230ba8663a2d@linaro.org


Huh, we should fix that one as well.


Best regards,
Krzysztof

Re: [PATCH] arm64: dts: exynos850: Add SRAM node

[Tudor Ambarus]

Hi!

On 4/14/26 12:08 PM, Krzysztof Kozlowski wrote:
> On 14/04/2026 11:00, Alexey Klimov wrote:
>> On Mon Apr 13, 2026 at 4:23 PM BST, Krzysztof Kozlowski wrote:
>>> On 13/04/2026 16:52, Alexey Klimov wrote:
>>>> SRAM is used by the ACPM protocol to retrieve the ACPM channels
>>>> information and configuration data. Add the SRAM node.
>>>>
>>>> Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org>
>>>> ---
>>>>  arch/arm64/boot/dts/exynos/exynos850.dtsi | 8 ++++++++
>>>>  1 file changed, 8 insertions(+)
>>>>
>>>> diff --git a/arch/arm64/boot/dts/exynos/exynos850.dtsi b/arch/arm64/boot/dts/exynos/exynos850.dtsi
>>>> index cb55015c8dce..cf4a6168846c 100644
>>>> --- a/arch/arm64/boot/dts/exynos/exynos850.dtsi
>>>> +++ b/arch/arm64/boot/dts/exynos/exynos850.dtsi
>>>> @@ -910,6 +910,14 @@ spi_2: spi@11d20000 {
>>>>  			};
>>>>  		};
>>>>  	};
>>>> +
>>>> +	apm_sram: sram@2039000 {
>>>> +		compatible = "mmio-sram";
>>>> +		reg = <0x0 0x2039000 0x40000>;
>>>> +		#address-cells = <1>;
>>>> +		#size-cells = <1>;
>>>> +		ranges = <0x0 0x0 0x2039000 0x40000>;
>>>
>>> You miss here children.
>>
>> Thank you! I guess I should convert it to smth like this:
>>
>> apm_sram: sram@2039000 {
>> 		compatible = "mmio-sram";
>> 		reg = <0x0 0x2039000 0x40000>;
>> 		ranges = <0x0 0x0 0x2039000 0x40000>;
>> 		#address-cells = <1>;
>> 		#size-cells = <1>;
>>
>> 		acpm_sram_region: sram-section@0 {
>> 			reg = <0x0 0x40000>;
> 
> This covers entire block, so feels pointless. Maybe requirement of
> children should be dropped. What's the point of having children? Why
> does the driver need them?
> 
>> 		};
>> 	};
>>
>> And then later reference shmem = &acpm_sram_region from acpm node.
>>
>>> Also, 'ranges' should be after 'reg'.
>>
>> Thanks, will fix this.
>>
>> FWIW this commit is a copy of commit 48e7821b26904
>> https://lore.kernel.org/r/20250207-gs101-acpm-dt-v4-1-230ba8663a2d@linaro.org
> 
> 
> Huh, we should fix that one as well.
> 

On gs101, likely on e850 too, ACPM parses the SRAM and discovers at runtime where
the TX/RX queue offsets are in SRAM. So we can't define static partitions in DT.
I remember that I thought about extending the SRAM driver to add dynamic
partitions (clients to request the mmio-sram driver to create partitions at
runtime), but it was just ACPM that's using SRAM, so I didn't need it.

Cheers,
ta