Re: [PATCH V2] arm64: dts: imx8mp: Add NPU Node

[Alexander Stein <alexander.stein@ew.tq-group.com>]

Hi Adam,

thanks for the update.

Am Sonntag, 22. Oktober 2023, 18:19:10 CEST schrieb Adam Ford:
> The NPU is based on the Vivante GC8000 and its power-domain
> is controlled my pgc_mlmix.  Since the power-domain uses
> some of these clocks, setup the clock parent and rates
> inside the power-domain, and add the NPU node.
> 
> The data sheet states the CLK_ML_AHB should be 300MHz for
> nominal, but 800MHz clock will divide down to 266 instead.
> Boards which operate in over-drive mode should update the
> clocks on their boards accordingly.  When the driver loads,
> the NPU numerates as:
> 
>  etnaviv-gpu 38500000.npu: model: GC8000, revision: 8002

There seems to be some race condition upon GPU/NPU detection. Sometimes I get 
these messages:
[    1.338100] etnaviv-gpu 38000000.gpu: model: GC7000, revision: 6204
[    1.344469] etnaviv-gpu 38008000.gpu: model: GC520, revision: 5341
[    1.350748] etnaviv-gpu 38500000.npu: model: GC0, revision: 0
[    1.356514] etnaviv-gpu 38500000.npu: Unknown GPU model

Sometimes I see GC8000 being detected as you have written. Despite that the 
patch itself looks good.
Reviewed-by: Alexander Stein <alexander.stein@ew.tq-group.com>

> 
> Signed-off-by: Adam Ford <aford173@gmail.com>
> ---
> 
> V2:  Move the clock parent and rate assignments to the ppc_mlmix node
>      since clock parents should be configured before they are used,
>      and pgc_mlmix uses them first.
>      Slow the clock rates down to confirm to nominal mode instead of
>      overdrive mode.
> 
> diff --git a/arch/arm64/boot/dts/freescale/imx8mp.dtsi
> b/arch/arm64/boot/dts/freescale/imx8mp.dtsi index
> c9a610ba4836..a18b9ba98ea2 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mp.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx8mp.dtsi
> @@ -887,6 +887,15 @@ pgc_mlmix: power-domain@24 {
>  						clocks = <&clk 
IMX8MP_CLK_ML_AXI>,
>  							 <&clk 
IMX8MP_CLK_ML_AHB>,
>  							 <&clk 
IMX8MP_CLK_NPU_ROOT>;
> +						assigned-clocks = 
<&clk IMX8MP_CLK_ML_CORE>,
> +								
  <&clk IMX8MP_CLK_ML_AXI>,
> +								
  <&clk IMX8MP_CLK_ML_AHB>;
> +						assigned-clock-
parents = <&clk IMX8MP_SYS_PLL1_800M>,
> +								
	 <&clk IMX8MP_SYS_PLL1_800M>,
> +								
	 <&clk IMX8MP_SYS_PLL1_800M>;
> +						assigned-clock-
rates = <800000000>,
> +								
       <800000000>,
> +								
       <300000000>;
>  					};
>  				};
>  			};
> @@ -2012,6 +2021,18 @@ vpumix_blk_ctrl: blk-ctrl@38330000 {
>  			interconnect-names = "g1", "g2", "vc8000e";
>  		};
> 
> +		npu: npu@38500000 {
> +			compatible = "vivante,gc";
> +			reg = <0x38500000 0x200000>;
> +			interrupts = <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>;
> +			clocks = <&clk IMX8MP_CLK_NPU_ROOT>,
> +				 <&clk IMX8MP_CLK_NPU_ROOT>,
> +				 <&clk IMX8MP_CLK_ML_AXI>,
> +				 <&clk IMX8MP_CLK_ML_AHB>;
> +			clock-names = "core", "shader", "bus", "reg";
> +			power-domains = <&pgc_mlmix>;
> +		};
> +
>  		gic: interrupt-controller@38800000 {
>  			compatible = "arm,gic-v3";
>  			reg = <0x38800000 0x10000>,


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