[PATCH v5 1/2] dt-bindings: display/msm: mdss-common: add memory-region property

[PATCH v5 1/2] dt-bindings: display/msm: mdss-common: add memory-region property

[Amit Pundir]

Add and document the reserved memory region property in the
mdss-common schema.

For now (sdm845-db845c), it points to a framebuffer memory
region reserved by the bootloader for splash screen.

Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
v5: Moving the dt-binding to mdss-common schema with
    updated commit message and property description.

v4: Adding this new dt-binding patch, in qcom,sdm845-mdss
    schema, in the v4 of the follow-up patch for
    sdm845-db845c.
    https://lore.kernel.org/lkml/20230712130215.666924-2-amit.pundir@linaro.org/

 .../devicetree/bindings/display/msm/mdss-common.yaml         | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/msm/mdss-common.yaml b/Documentation/devicetree/bindings/display/msm/mdss-common.yaml
index ccd7d6417523..84ed2757ded5 100644
--- a/Documentation/devicetree/bindings/display/msm/mdss-common.yaml
+++ b/Documentation/devicetree/bindings/display/msm/mdss-common.yaml
@@ -77,6 +77,12 @@ properties:
     items:
       - description: MDSS_CORE reset
 
+  memory-region:
+    maxItems: 1
+    description:
+      Phandle to a node describing a reserved framebuffer memory region.
+      For example, the splash memory region set up by the bootloader.
+
 required:
   - reg
   - reg-names
-- 
2.25.1

[PATCH v5 2/2] arm64: dts: qcom: sdm845-db845c: Mark cont splash memory region as reserved

[Amit Pundir]

Adding a reserved memory region for the framebuffer memory
(the splash memory region set up by the bootloader).

Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
v5: Re-sending with updated dt-bindings patch in mdss-common
    schema.

v4: Re-sending this along with a new dt-bindings patch to
    document memory-region property in qcom,sdm845-mdss
    schema and keep dtbs_check happy.

v3: Point this reserved region to MDSS.

v2: Updated commit message.

There was some dicussion on v1 but it didn't go anywhere,
https://lore.kernel.org/linux-kernel/20230124182857.1524912-1-amit.pundir@linaro.org/T/#u.
The general consensus is that this memory should be freed and be
made resuable but that (releasing this piece of memory) has been
tried before and it is not trivial to return the reserved memory
node to the system RAM pool in this case.

 arch/arm64/boot/dts/qcom/sdm845-db845c.dts | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/sdm845-db845c.dts b/arch/arm64/boot/dts/qcom/sdm845-db845c.dts
index d6b464cb61d6..f546f6f57c1e 100644
--- a/arch/arm64/boot/dts/qcom/sdm845-db845c.dts
+++ b/arch/arm64/boot/dts/qcom/sdm845-db845c.dts
@@ -101,6 +101,14 @@ hdmi_con: endpoint {
 		};
 	};
 
+	reserved-memory {
+		/* Cont splash region set up by the bootloader */
+		cont_splash_mem: framebuffer@9d400000 {
+			reg = <0x0 0x9d400000 0x0 0x2400000>;
+			no-map;
+		};
+	};
+
 	lt9611_1v8: lt9611-vdd18-regulator {
 		compatible = "regulator-fixed";
 		regulator-name = "LT9611_1V8";
@@ -506,6 +514,7 @@ &i2c14 {
 };
 
 &mdss {
+	memory-region = <&cont_splash_mem>;
 	status = "okay";
 };
 
-- 
2.25.1

Re: [PATCH v5 2/2] arm64: dts: qcom: sdm845-db845c: Mark cont splash memory region as reserved

[Caleb Connolly]

On 13/07/2023 17:52, Amit Pundir wrote:
> Adding a reserved memory region for the framebuffer memory
> (the splash memory region set up by the bootloader).
> 
> Signed-off-by: Amit Pundir <amit.pundir@linaro.org>

Reviewed-by: Caleb Connolly <caleb.connolly@linaro.org>
> ---
> v5: Re-sending with updated dt-bindings patch in mdss-common
>     schema.
> 
> v4: Re-sending this along with a new dt-bindings patch to
>     document memory-region property in qcom,sdm845-mdss
>     schema and keep dtbs_check happy.
> 
> v3: Point this reserved region to MDSS.
> 
> v2: Updated commit message.
> 
> There was some dicussion on v1 but it didn't go anywhere,
> https://lore.kernel.org/linux-kernel/20230124182857.1524912-1-amit.pundir@linaro.org/T/#u.
> The general consensus is that this memory should be freed and be
> made resuable but that (releasing this piece of memory) has been
> tried before and it is not trivial to return the reserved memory
> node to the system RAM pool in this case.
> 
>  arch/arm64/boot/dts/qcom/sdm845-db845c.dts | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/qcom/sdm845-db845c.dts b/arch/arm64/boot/dts/qcom/sdm845-db845c.dts
> index d6b464cb61d6..f546f6f57c1e 100644
> --- a/arch/arm64/boot/dts/qcom/sdm845-db845c.dts
> +++ b/arch/arm64/boot/dts/qcom/sdm845-db845c.dts
> @@ -101,6 +101,14 @@ hdmi_con: endpoint {
>  		};
>  	};
>  
> +	reserved-memory {
> +		/* Cont splash region set up by the bootloader */
> +		cont_splash_mem: framebuffer@9d400000 {
> +			reg = <0x0 0x9d400000 0x0 0x2400000>;
> +			no-map;
> +		};
> +	};
> +
>  	lt9611_1v8: lt9611-vdd18-regulator {
>  		compatible = "regulator-fixed";
>  		regulator-name = "LT9611_1V8";
> @@ -506,6 +514,7 @@ &i2c14 {
>  };
>  
>  &mdss {
> +	memory-region = <&cont_splash_mem>;
>  	status = "okay";
>  };
>  

-- 
// Caleb (they/them)

Re: [PATCH v5 1/2] dt-bindings: display/msm: mdss-common: add memory-region property

[Rob Herring]

On Thu, 13 Jul 2023 22:22:37 +0530, Amit Pundir wrote:
> Add and document the reserved memory region property in the
> mdss-common schema.
> 
> For now (sdm845-db845c), it points to a framebuffer memory
> region reserved by the bootloader for splash screen.
> 
> Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
> ---
> v5: Moving the dt-binding to mdss-common schema with
>     updated commit message and property description.
> 
> v4: Adding this new dt-binding patch, in qcom,sdm845-mdss
>     schema, in the v4 of the follow-up patch for
>     sdm845-db845c.
>     https://lore.kernel.org/lkml/20230712130215.666924-2-amit.pundir@linaro.org/
> 
>  .../devicetree/bindings/display/msm/mdss-common.yaml         | 5 +++++
>  1 file changed, 5 insertions(+)
> 

Reviewed-by: Rob Herring <robh@kernel.org>

Re: [PATCH v5 1/2] dt-bindings: display/msm: mdss-common: add memory-region property

[Krzysztof Kozlowski]

On 13/07/2023 18:52, Amit Pundir wrote:
> Add and document the reserved memory region property in the
> mdss-common schema.
> 
> For now (sdm845-db845c), it points to a framebuffer memory
> region reserved by the bootloader for splash screen.
> 
> Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
> ---

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

Re: [PATCH v5 2/2] arm64: dts: qcom: sdm845-db845c: Mark cont splash memory region as reserved

[Krzysztof Kozlowski]

On 13/07/2023 18:52, Amit Pundir wrote:
> Adding a reserved memory region for the framebuffer memory
> (the splash memory region set up by the bootloader).
> 
> Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
> ---

I think your commit msg misses describing the actual problem, impact to
users and finally cc-stable.

Best regards,
Krzysztof