[PATCH] arm64: dts: imx8mm: Add GPU node

[PATCH] arm64: dts: imx8mm: Add GPU node

[Adam Ford]

According to the documentation from NXP, the i.MX8M Nano has a
Vivante GC7000 Ultra Lite as its GPU core.

With this patch, the Etnaviv driver presents the GPU as:
   etnaviv-gpu 38000000.gpu: model: GC7000, revision: 6203

It uses the GPCV2 controller to enable the power domain for the GPU.

Signed-off-by: Adam Ford <aford173@gmail.com>
---
This patch depends on a series located:
https://patchwork.kernel.org/project/linux-arm-kernel/list/?series=368903
and

diff --git a/arch/arm64/boot/dts/freescale/imx8mn.dtsi b/arch/arm64/boot/dts/freescale/imx8mn.dtsi
index 605e6dbd2c6f..62c8cd3dea7c 100644
--- a/arch/arm64/boot/dts/freescale/imx8mn.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mn.dtsi
@@ -4,6 +4,8 @@
  */
 
 #include <dt-bindings/clock/imx8mn-clock.h>
+#include <dt-bindings/power/imx8mn-power.h>
+#include <dt-bindings/reset/imx8mq-reset.h>
 #include <dt-bindings/gpio/gpio.h>
 #include <dt-bindings/input/input.h>
 #include <dt-bindings/interrupt-controller/arm-gic.h>
@@ -1019,6 +1021,31 @@ gpmi: nand-controller@33002000 {
 			status = "disabled";
 		};
 
+		gpu: gpu@38000000 {
+			compatible = "vivante,gc";
+			reg = <0x38000000 0x8000>;
+			interrupts = <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk IMX8MN_CLK_GPU_AHB>,
+				<&clk IMX8MN_CLK_GPU_BUS_ROOT>,
+				<&clk IMX8MN_CLK_GPU_CORE_ROOT>,
+				<&clk IMX8MN_CLK_GPU_SHADER_DIV>;
+			clock-names = "reg", "bus", "core", "shader";
+			assigned-clocks = <&clk IMX8MN_CLK_GPU_CORE_SRC>,
+					  <&clk IMX8MN_CLK_GPU_SHADER_SRC>,
+					  <&clk IMX8MN_CLK_GPU_AXI>,
+					  <&clk IMX8MN_CLK_GPU_AHB>,
+					  <&clk IMX8MN_GPU_PLL>,
+					  <&clk IMX8MN_CLK_GPU_CORE_DIV>,
+					  <&clk IMX8MN_CLK_GPU_SHADER_DIV>;
+			assigned-clock-parents = <&clk IMX8MN_GPU_PLL_OUT>,
+						  <&clk IMX8MN_GPU_PLL_OUT>,
+						  <&clk IMX8MN_SYS_PLL1_800M>,
+						  <&clk IMX8MN_SYS_PLL1_800M>;
+			assigned-clock-rates = <0>, <0>, <800000000>, <400000000>, <1200000000>,
+				<400000000>, <400000000>;
+			power-domains = <&pgc_gpumix>;
+		};
+
 		gic: interrupt-controller@38800000 {
 			compatible = "arm,gic-v3";
 			reg = <0x38800000 0x10000>,
-- 
2.25.1

Re: [PATCH] arm64: dts: imx8mm: Add GPU node

[Marek Vasut]

On 10/22/20 7:16 PM, Adam Ford wrote:
> According to the documentation from NXP, the i.MX8M Nano has a
> Vivante GC7000 Ultra Lite as its GPU core.
> 
> With this patch, the Etnaviv driver presents the GPU as:
>    etnaviv-gpu 38000000.gpu: model: GC7000, revision: 6203
> 
> It uses the GPCV2 controller to enable the power domain for the GPU.

Subject should say 8mn , not 8mm .

Are the assigned-clock-rates correct ?

Re: [PATCH] arm64: dts: imx8mm: Add GPU node

[Adam Ford]

On Thu, Oct 22, 2020 at 1:17 PM Marek Vasut <marex@denx.de> wrote:
>
> On 10/22/20 7:16 PM, Adam Ford wrote:
> > According to the documentation from NXP, the i.MX8M Nano has a
> > Vivante GC7000 Ultra Lite as its GPU core.
> >
> > With this patch, the Etnaviv driver presents the GPU as:
> >    etnaviv-gpu 38000000.gpu: model: GC7000, revision: 6203
> >
> > It uses the GPCV2 controller to enable the power domain for the GPU.
>
> Subject should say 8mn , not 8mm .

ugh.. My mistake.  I'll submit a V2 once other have had a chance to
give some feedback.

Maybe NXP can comment on the dialog below.

>
> Are the assigned-clock-rates correct ?

I used the assigned clock rates from the vendor kernel, with the
exception of running at 400MHz instead of 600MHz.  According to the
datasheet, the GPU clock needs to be 400MHZ to run at 0.85V. The
600MHz operating point for the GPU requires a 0.95V operating point.
Since the default operating point for the Nano shows 0.85V, I left the
GPU clock lower to match the normal operating speed.  This varies a
bit from the vendor kernel, but their kernel is also showing a 0.95V
operating point, so I think that's why they are specifying a 600MHz
operating point.

On the Beacon embedded board, we're driving the LPDDR to 800MHz which
requires the ARM to run at .95V.   I was able to override the
assigned-clock rates for my board to run at 600MHz, and change the ARM
operating point to .95V to meet the spec.

My intent was to use the defaults and let the board files override
them.   If you want, I can try to look through the board files to see
what operating point their using and propose updates to those
respective device trees to address the clocks on those boards.

adam

Re: [PATCH] arm64: dts: imx8mm: Add GPU node

[Lucas Stach]

On Do, 2020-10-22 at 13:31 -0500, Adam Ford wrote:
> On Thu, Oct 22, 2020 at 1:17 PM Marek Vasut <marex@denx.de> wrote:
> > On 10/22/20 7:16 PM, Adam Ford wrote:
> > > According to the documentation from NXP, the i.MX8M Nano has a
> > > Vivante GC7000 Ultra Lite as its GPU core.
> > > 
> > > With this patch, the Etnaviv driver presents the GPU as:
> > >    etnaviv-gpu 38000000.gpu: model: GC7000, revision: 6203
> > > 
> > > It uses the GPCV2 controller to enable the power domain for the
> > > GPU.
> > 
> > Subject should say 8mn , not 8mm .
> 
> ugh.. My mistake.  I'll submit a V2 once other have had a chance to
> give some feedback.
> 
> Maybe NXP can comment on the dialog below.
> 
> > Are the assigned-clock-rates correct ?
> 
> I used the assigned clock rates from the vendor kernel, with the
> exception of running at 400MHz instead of 600MHz.  According to the
> datasheet, the GPU clock needs to be 400MHZ to run at 0.85V. The
> 600MHz operating point for the GPU requires a 0.95V operating point.
> Since the default operating point for the Nano shows 0.85V, I left
> the
> GPU clock lower to match the normal operating speed.  This varies a
> bit from the vendor kernel, but their kernel is also showing a 0.95V
> operating point, so I think that's why they are specifying a 600MHz
> operating point.
> 
> On the Beacon embedded board, we're driving the LPDDR to 800MHz which
> requires the ARM to run at .95V.   I was able to override the
> assigned-clock rates for my board to run at 600MHz, and change the
> ARM
> operating point to .95V to meet the spec.
> 
> My intent was to use the defaults and let the board files override
> them.   If you want, I can try to look through the board files to see
> what operating point their using and propose updates to those
> respective device trees to address the clocks on those boards.

I think this is fine as-is with this explanation. At least we have a
precedent in the i.MX8MQ DT where the assigned clocks are for the base
(non overdrive) operating point and boards can choose to override it if
they want to use the overdrive OPP. At least until we add proper
frequency scaling in etnaviv, which should obsolete those fixed clock
rates.

Regards,
Lucas

Re: [PATCH] arm64: dts: imx8mm: Add GPU node

[Krzysztof Kozlowski]

On Thu, Oct 22, 2020 at 12:16:39PM -0500, Adam Ford wrote:
> According to the documentation from NXP, the i.MX8M Nano has a
> Vivante GC7000 Ultra Lite as its GPU core.
> 
> With this patch, the Etnaviv driver presents the GPU as:
>    etnaviv-gpu 38000000.gpu: model: GC7000, revision: 6203
> 
> It uses the GPCV2 controller to enable the power domain for the GPU.
> 
> Signed-off-by: Adam Ford <aford173@gmail.com>
> ---
> This patch depends on a series located:
> https://patchwork.kernel.org/project/linux-arm-kernel/list/?series=368903
> and
> 
> diff --git a/arch/arm64/boot/dts/freescale/imx8mn.dtsi b/arch/arm64/boot/dts/freescale/imx8mn.dtsi
> index 605e6dbd2c6f..62c8cd3dea7c 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mn.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx8mn.dtsi
> @@ -4,6 +4,8 @@
>   */
>  
>  #include <dt-bindings/clock/imx8mn-clock.h>
> +#include <dt-bindings/power/imx8mn-power.h>
> +#include <dt-bindings/reset/imx8mq-reset.h>
>  #include <dt-bindings/gpio/gpio.h>
>  #include <dt-bindings/input/input.h>
>  #include <dt-bindings/interrupt-controller/arm-gic.h>
> @@ -1019,6 +1021,31 @@ gpmi: nand-controller@33002000 {
>  			status = "disabled";
>  		};
>  
> +		gpu: gpu@38000000 {
> +			compatible = "vivante,gc";
> +			reg = <0x38000000 0x8000>;
> +			interrupts = <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>;
> +			clocks = <&clk IMX8MN_CLK_GPU_AHB>,
> +				<&clk IMX8MN_CLK_GPU_BUS_ROOT>,
> +				<&clk IMX8MN_CLK_GPU_CORE_ROOT>,
> +				<&clk IMX8MN_CLK_GPU_SHADER_DIV>;
> +			clock-names = "reg", "bus", "core", "shader";
> +			assigned-clocks = <&clk IMX8MN_CLK_GPU_CORE_SRC>,
> +					  <&clk IMX8MN_CLK_GPU_SHADER_SRC>,
> +					  <&clk IMX8MN_CLK_GPU_AXI>,
> +					  <&clk IMX8MN_CLK_GPU_AHB>,
> +					  <&clk IMX8MN_GPU_PLL>,
> +					  <&clk IMX8MN_CLK_GPU_CORE_DIV>,
> +					  <&clk IMX8MN_CLK_GPU_SHADER_DIV>;
> +			assigned-clock-parents = <&clk IMX8MN_GPU_PLL_OUT>,
> +						  <&clk IMX8MN_GPU_PLL_OUT>,
> +						  <&clk IMX8MN_SYS_PLL1_800M>,
> +						  <&clk IMX8MN_SYS_PLL1_800M>;
> +			assigned-clock-rates = <0>, <0>, <800000000>, <400000000>, <1200000000>,
> +				<400000000>, <400000000>;

Plaese indent it till '=' and put each entry in new line. This will
match other 'assigned-clock' properties.

Best regards,
Krzysztof

Re: [PATCH] arm64: dts: imx8mm: Add GPU node

[Adam Ford]

On Fri, Oct 23, 2020 at 3:25 AM Lucas Stach <l.stach@pengutronix.de> wrote:
>
> On Do, 2020-10-22 at 13:31 -0500, Adam Ford wrote:
> > On Thu, Oct 22, 2020 at 1:17 PM Marek Vasut <marex@denx.de> wrote:
> > > On 10/22/20 7:16 PM, Adam Ford wrote:
> > > > According to the documentation from NXP, the i.MX8M Nano has a
> > > > Vivante GC7000 Ultra Lite as its GPU core.
> > > >
> > > > With this patch, the Etnaviv driver presents the GPU as:
> > > >    etnaviv-gpu 38000000.gpu: model: GC7000, revision: 6203
> > > >
> > > > It uses the GPCV2 controller to enable the power domain for the
> > > > GPU.
> > >
> > > Subject should say 8mn , not 8mm .
> >
> > ugh.. My mistake.  I'll submit a V2 once other have had a chance to
> > give some feedback.
> >
> > Maybe NXP can comment on the dialog below.
> >
> > > Are the assigned-clock-rates correct ?
> >
> > I used the assigned clock rates from the vendor kernel, with the
> > exception of running at 400MHz instead of 600MHz.  According to the
> > datasheet, the GPU clock needs to be 400MHZ to run at 0.85V. The
> > 600MHz operating point for the GPU requires a 0.95V operating point.
> > Since the default operating point for the Nano shows 0.85V, I left
> > the
> > GPU clock lower to match the normal operating speed.  This varies a
> > bit from the vendor kernel, but their kernel is also showing a 0.95V
> > operating point, so I think that's why they are specifying a 600MHz
> > operating point.
> >
> > On the Beacon embedded board, we're driving the LPDDR to 800MHz which
> > requires the ARM to run at .95V.   I was able to override the
> > assigned-clock rates for my board to run at 600MHz, and change the
> > ARM
> > operating point to .95V to meet the spec.
> >
> > My intent was to use the defaults and let the board files override
> > them.   If you want, I can try to look through the board files to see
> > what operating point their using and propose updates to those
> > respective device trees to address the clocks on those boards.
>
> I think this is fine as-is with this explanation. At least we have a
> precedent in the i.MX8MQ DT where the assigned clocks are for the base
> (non overdrive) operating point and boards can choose to override it if
> they want to use the overdrive OPP. At least until we add proper
> frequency scaling in etnaviv, which should obsolete those fixed clock
> rates.

I have to do a V2 from the feedback of Krzysztof.  I will expand the
commit message to include the description of the 400MHz vs 600MHz
clocking and the need for adjusting the operating points.

adam
>
> Regards,
> Lucas
>