Re: [PATCH v3 1/5] Platform/RaspberryPi4: Add a basic thermal zone

["Jeremy Linton" <jeremy.linton@arm.com>]

Hi,

On 8/31/20 8:15 AM, Pete Batard wrote:
> One general, non-blocking comment below:
> 
> On 2020.08.28 23:02, Jeremy Linton wrote:
>> Rather than exporting the temp sensor or mailbox
>> in ACPI land we can wrap them in AML and use the default
>> ACPI drivers provided by the OS. This enables the use of
>> "sensors" in linux to report the SOC temp.
>>
>> As a first pass add a basic passive cooling ACPI thermalzone
>> with trip points for passive cooling (throttling) handled
>> by the vc firmware, hibernate and critical shutdown. The
>> vc apparently kicks in at ~80C, so the hibernate and critical
>> set points are set at +5 and +10 of that. In the future
>> CPPC should be able to monitor the thermal throttling.
>>
>> Cc: Leif Lindholm <leif@nuviainc.com>
>> Cc: Pete Batard <pete@akeo.ie>
>> Cc: Andrei Warkentin <awarkentin@vmware.com>
>> Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
>> Cc: Samer El-Haj-Mahmoud <Samer.El-Haj-Mahmoud@arm.com>
>> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
>> Reviewed-by: Pete Batard <@pbatard>
>> ---
>>   Platform/RaspberryPi/AcpiTables/Dsdt.asl           | 31 
>> ++++++++++++++++++++++
>>   .../Bcm27xx/Include/IndustryStandard/Bcm2711.h     |  2 ++
>>   2 files changed, 33 insertions(+)
>>
>> diff --git a/Platform/RaspberryPi/AcpiTables/Dsdt.asl 
>> b/Platform/RaspberryPi/AcpiTables/Dsdt.asl
>> index 353af2d876..73067aefd2 100644
>> --- a/Platform/RaspberryPi/AcpiTables/Dsdt.asl
>> +++ b/Platform/RaspberryPi/AcpiTables/Dsdt.asl
>> @@ -252,6 +252,37 @@ DefinitionBlock ("Dsdt.aml", "DSDT", 5, "RPIFDN", 
>> "RPI", 2)
>>           }
>>
>>         })
>>
>>       }
>>
>> +
>>
>> +    // Define a simple thermal zone. The idea here is we compute the 
>> SOC temp
>>
>> +    // via a register we can read, and give it to the OS. This 
>> enables basic
>>
>> +    // reports from the "sensors" utility, and the OS can then poll 
>> and take
>>
>> +    // actions if that temp exceeds any of the given thresholds.
>>
>> +    Device (EC0)
> 
> Just going to point out that all the other ACPI devices we seem to 
> define have 4 characters, so I'm not sure if we're breaking a convention 
> by introducing a 3 character one here...

Well not an ACPI spec convention, because it seems the spec examples are 
mostly 3 characters. EDK2 OTOH, seems to be largely 4 but there are a 
fair number of 3 character device/etc methods around

I'm not sure it matters, unless there is a edk2 convention I'm unaware of.

> 
>>
>> +    {
>>
>> +      Name (_HID, EISAID ("PNP0C06"))
>>
>> +      Name (_CCA, 0x0)
>>
>> +
>>
>> +      // all temps in are tenths of K (aka 2732 is the min temps in 
>> Linux (aka 0C))
>>
>> +      ThermalZone (TZ0) {
> 
> Likewise, what I'm seeing by googling around for ThermalZone () names 
> would be 4 character ones such as "TZ00", "TZ01" or "TZS0" (For 'Thermal 
> Zone Sensor 0') or "TMZN" for single entries.
> 
>>
>> +        Method (_TMP, 0, Serialized) {
>>
>> +          OperationRegion (TEMS, SystemMemory, THERM_SENSOR, 0x8)
>>
>> +          Field (TEMS, DWordAcc, NoLock, Preserve) {
>>
>> +            TMPS, 32
>>
>> +          }
>>
>> +          return (((419949 - ((TMPS & 0x3ff) * 487)) / 100) + 2732);
>>
>> +        }
>>
>> +        Method (_SCP, 3) { }               // receive cooling policy 
>> from OS
>>
>> +
>>
>> +        Method (_CRT) { Return (3632) }    // (90C) Critical temp 
>> point (immediate power-off)
>>
>> +        Method (_HOT) { Return (3582) }    // (85C) HOT state where 
>> OS should hibernate
>>
>> +        Method (_PSV) { Return (3532) }    // (80C) Passive cooling 
>> (CPU throttling) trip point
>>
>> +
>>
>> +        // SSDT inserts _AC0/_AL0 @60C here, if a FAN is configured
>>
>> +
>>
>> +        Name (_TZP, 10)                   //The OSPM must poll this 
>> device every 1 seconds
>>
>> +        Name (_PSL, Package () { \_SB_.CPU0, \_SB_.CPU1, \_SB_.CPU2, 
>> \_SB_.CPU3 })
>>
>> +      }
>>
>> +    }
>>
>>   #endif
>>
>>
>>     }
>>
>> diff --git 
>> a/Silicon/Broadcom/Bcm27xx/Include/IndustryStandard/Bcm2711.h 
>> b/Silicon/Broadcom/Bcm27xx/Include/IndustryStandard/Bcm2711.h
>> index e9c81cafa1..86906b2438 100644
>> --- a/Silicon/Broadcom/Bcm27xx/Include/IndustryStandard/Bcm2711.h
>> +++ b/Silicon/Broadcom/Bcm27xx/Include/IndustryStandard/Bcm2711.h
>> @@ -86,4 +86,6 @@
>>   #define GENET_BASE_ADDRESS         FixedPcdGet64 
>> (PcdBcmGenetRegistersAddress)
>>
>>   #define GENET_LENGTH               0x00010000
>>
>>
>> +#define THERM_SENSOR               0xfd5d2200
>>
>> +
>>
>>   #endif /* BCM2711_H__ */
>>
> 
> Reviewed-by: Pete Batard <pete@akeo.ie>