Re: [PATCH 06/19] arm64: dts: qcom: msm8939: Fix CPU node "enable-method" property dependencies

[Stephan Gerhold <stephan.gerhold@linaro.org>]

On Thu, Apr 03, 2025 at 09:59:27PM -0500, Rob Herring (Arm) wrote:
> The "qcom,acc" and "qcom,saw" properties aren't valid with "spin-table"
> enable-method nor are they used on 64-bit kernels, so they can be
> dropped.
> 

The bootloader we currently use on these devices reads these properties
to set up the spin-table, so removing these will break booting secondary
CPU cores.

The motivation for implementing it that way was that 32-bit vs 64-bit
kernel shouldn't be relevant for the describing the hardware blocks in
the device tree. The code in the bootloader is generic and handles
different SoCs (e.g. msm8916 with 4 cores and msm8939 with 8 cores, the
enable sequences are identical).

Can we keep this in somehow? To be fair, I'm not sure what property we
could match on to check if these properties are allowed ...

Thanks,
Stephan

> The "spin-table" enable-method requires "cpu-release-addr" property,
> so add a dummy entry. It is assumed the bootloader will fill in the
> correct values.
> 
> Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
> ---
>  arch/arm64/boot/dts/qcom/msm8939.dtsi | 24 ++++++++----------------
>  1 file changed, 8 insertions(+), 16 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/qcom/msm8939.dtsi b/arch/arm64/boot/dts/qcom/msm8939.dtsi
> index 7cd5660de1b3..36f2ba3fb81c 100644
> --- a/arch/arm64/boot/dts/qcom/msm8939.dtsi
> +++ b/arch/arm64/boot/dts/qcom/msm8939.dtsi
> @@ -46,10 +46,9 @@ cpu0: cpu@100 {
>  			compatible = "arm,cortex-a53";
>  			device_type = "cpu";
>  			enable-method = "spin-table";
> +			cpu-release-addr = /bits/ 64 <0>;
>  			reg = <0x100>;
>  			next-level-cache = <&l2_1>;
> -			qcom,acc = <&acc0>;
> -			qcom,saw = <&saw0>;
>  			cpu-idle-states = <&cpu_sleep_0>;
>  			clocks = <&apcs1_mbox>;
>  			#cooling-cells = <2>;
> @@ -64,10 +63,9 @@ cpu1: cpu@101 {
>  			compatible = "arm,cortex-a53";
>  			device_type = "cpu";
>  			enable-method = "spin-table";
> +			cpu-release-addr = /bits/ 64 <0>;
>  			reg = <0x101>;
>  			next-level-cache = <&l2_1>;
> -			qcom,acc = <&acc1>;
> -			qcom,saw = <&saw1>;
>  			cpu-idle-states = <&cpu_sleep_0>;
>  			clocks = <&apcs1_mbox>;
>  			#cooling-cells = <2>;
> @@ -77,10 +75,9 @@ cpu2: cpu@102 {
>  			compatible = "arm,cortex-a53";
>  			device_type = "cpu";
>  			enable-method = "spin-table";
> +			cpu-release-addr = /bits/ 64 <0>;
>  			reg = <0x102>;
>  			next-level-cache = <&l2_1>;
> -			qcom,acc = <&acc2>;
> -			qcom,saw = <&saw2>;
>  			cpu-idle-states = <&cpu_sleep_0>;
>  			clocks = <&apcs1_mbox>;
>  			#cooling-cells = <2>;
> @@ -90,10 +87,9 @@ cpu3: cpu@103 {
>  			compatible = "arm,cortex-a53";
>  			device_type = "cpu";
>  			enable-method = "spin-table";
> +			cpu-release-addr = /bits/ 64 <0>;
>  			reg = <0x103>;
>  			next-level-cache = <&l2_1>;
> -			qcom,acc = <&acc3>;
> -			qcom,saw = <&saw3>;
>  			cpu-idle-states = <&cpu_sleep_0>;
>  			clocks = <&apcs1_mbox>;
>  			#cooling-cells = <2>;
> @@ -103,9 +99,8 @@ cpu4: cpu@0 {
>  			compatible = "arm,cortex-a53";
>  			device_type = "cpu";
>  			enable-method = "spin-table";
> +			cpu-release-addr = /bits/ 64 <0>;
>  			reg = <0x0>;
> -			qcom,acc = <&acc4>;
> -			qcom,saw = <&saw4>;
>  			cpu-idle-states = <&cpu_sleep_0>;
>  			clocks = <&apcs0_mbox>;
>  			#cooling-cells = <2>;
> @@ -121,10 +116,9 @@ cpu5: cpu@1 {
>  			compatible = "arm,cortex-a53";
>  			device_type = "cpu";
>  			enable-method = "spin-table";
> +			cpu-release-addr = /bits/ 64 <0>;
>  			reg = <0x1>;
>  			next-level-cache = <&l2_0>;
> -			qcom,acc = <&acc5>;
> -			qcom,saw = <&saw5>;
>  			cpu-idle-states = <&cpu_sleep_0>;
>  			clocks = <&apcs0_mbox>;
>  			#cooling-cells = <2>;
> @@ -134,10 +128,9 @@ cpu6: cpu@2 {
>  			compatible = "arm,cortex-a53";
>  			device_type = "cpu";
>  			enable-method = "spin-table";
> +			cpu-release-addr = /bits/ 64 <0>;
>  			reg = <0x2>;
>  			next-level-cache = <&l2_0>;
> -			qcom,acc = <&acc6>;
> -			qcom,saw = <&saw6>;
>  			cpu-idle-states = <&cpu_sleep_0>;
>  			clocks = <&apcs0_mbox>;
>  			#cooling-cells = <2>;
> @@ -147,10 +140,9 @@ cpu7: cpu@3 {
>  			compatible = "arm,cortex-a53";
>  			device_type = "cpu";
>  			enable-method = "spin-table";
> +			cpu-release-addr = /bits/ 64 <0>;
>  			reg = <0x3>;
>  			next-level-cache = <&l2_0>;
> -			qcom,acc = <&acc7>;
> -			qcom,saw = <&saw7>;
>  			cpu-idle-states = <&cpu_sleep_0>;
>  			clocks = <&apcs0_mbox>;
>  			#cooling-cells = <2>;
> 
> -- 
> 2.47.2
>