Re: [PATCH v2 1/4] Platform/RaspberryPi4: Add a basic thermal zone

["Ard Biesheuvel" <ard.biesheuvel@arm.com>]

On 8/20/20 6:42 AM, 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.
> 
> This commit also adds 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>

This looks ok to me but I did not receive patch #4 or the cover letter.

> ---
>   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)
> +    {
> +      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) {
> +        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__ */
>