linux-kernel - Re: [PATCH v2] add pmu to amlogic meson sm1

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Message-ID: <65cde84a-8f8b-ac57-9b66-2b8d6378dbfa@arm.com>
Date:   Mon, 7 Feb 2022 13:20:22 +0000
From:   Robin Murphy <robin.murphy@....com>
To:     Neil Armstrong <narmstrong@...libre.com>,
        Benjamin Mordaunt <crawford.benjamin15@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Kevin Hilman <khilman@...libre.com>,
        Jerome Brunet <jbrunet@...libre.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>
Cc:     devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] add pmu to amlogic meson sm1

On 2022-02-07 08:14, Neil Armstrong wrote:
> Hi,
> 
> On 06/02/2022 15:43, Benjamin Mordaunt wrote:
>> ---
>> The dts for meson sm1 appears to omit the SoC's PMU,
>> which is essential for accessing perf events regarding
>> e.g. cache on e.g. the Odroid C4 platform. Add it.
>>
>>   arch/arm64/boot/dts/amlogic/meson-sm1.dtsi | 13 ++++++++++++-
>>   1 file changed, 12 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/boot/dts/amlogic/meson-sm1.dtsi 
>> b/arch/arm64/boot/dts/amlogic/meson-sm1.dtsi
>> index 3d8b1f4f2..4147eecd2 100644
>> --- a/arch/arm64/boot/dts/amlogic/meson-sm1.dtsi
>> +++ b/arch/arm64/boot/dts/amlogic/meson-sm1.dtsi
>> @@ -6,6 +6,8 @@
>>   #include "meson-g12-common.dtsi"
>>   #include <dt-bindings/clock/axg-audio-clkc.h>
>> +#include <dt-bindings/interrupt-controller/irq.h>
>> +#include <dt-bindings/interrupt-controller/arm-gic.h>
>>   #include <dt-bindings/power/meson-sm1-power.h>
>>   #include <dt-bindings/reset/amlogic,meson-axg-audio-arb.h>
>>   #include <dt-bindings/reset/amlogic,meson-g12a-audio-reset.h>
>> @@ -90,7 +92,16 @@ l2: l2-cache0 {
>>               compatible = "cache";
>>           };
>>       };
>> -
>> +
>> +    arm-pmu {
>> +        compatible = "arm,cortex-a55-pmu";
>> +        interrupts = <GIC_SPI 137 IRQ_TYPE_LEVEL_HIGH>,
>> +                 <GIC_SPI 138 IRQ_TYPE_LEVEL_HIGH>,
>> +                 <GIC_SPI 153 IRQ_TYPE_LEVEL_HIGH>,
>> +                 <GIC_SPI 154 IRQ_TYPE_LEVEL_HIGH>;
>> +        interrupt-affinity = <&cpu0>, <&cpu1>, <&cpu2>, <&cpu3>;
>> +    };
>> +
>>       cpu_opp_table: opp-table {
>>           compatible = "operating-points-v2";
>>           opp-shared;
> 
> Please see Marc's comments about PMU support:
> http://lore.kernel.org/r/8735pcq63o.wl-maz@kernel.org

If SM1 actually has distinct per-core interrupts as the patch implies 
then it's fine - it's only G12B and anything else that combines multiple 
PMU IRQs into a single SPI which are unsupportable.

Robin.