>> Current implementation of processor_thermal performs software throttling
>> in fixed steps of "20%" which can be too coarse for some platforms.
>> We observed some performance gain after reducing the throttle percentage.
>> Change the CPUFREQ thermal reduction percentage and maximum thermal steps
>> to be configurable. Also, update the default values of both for Nvidia
>> Tegra241 (Grace) SoC. The thermal reduction percentage is reduced to "5%"
>> and accordingly the maximum number of thermal steps are increased as they
>> are derived from the reduction percentage.
>>
>> Signed-off-by: Srikar Srimath Tirumala <[email protected]>
>> Co-developed-by: Sumit Gupta <[email protected]>
>> Signed-off-by: Sumit Gupta <[email protected]>
>> ---
>> drivers/acpi/arm64/Makefile | 1 +
>> drivers/acpi/arm64/thermal_cpufreq.c | 22 +++++++++++++
>> drivers/acpi/internal.h | 9 +++++
>> drivers/acpi/processor_thermal.c | 49 +++++++++++++++++++++++-----
>> 4 files changed, 72 insertions(+), 9 deletions(-)
>> create mode 100644 drivers/acpi/arm64/thermal_cpufreq.c
>>
>> diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile
>> index 143debc1ba4a..726944648c9b 100644
>> --- a/drivers/acpi/arm64/Makefile
>> +++ b/drivers/acpi/arm64/Makefile
>> @@ -5,3 +5,4 @@ obj-$(CONFIG_ACPI_GTDT) += gtdt.o
>> obj-$(CONFIG_ACPI_APMT) += apmt.o
>> obj-$(CONFIG_ARM_AMBA) += amba.o
>> obj-y += dma.o init.o
>> +obj-y += thermal_cpufreq.o
>> diff --git a/drivers/acpi/arm64/thermal_cpufreq.c b/drivers/acpi/arm64/thermal_cpufreq.c
>> new file mode 100644
>> index 000000000000..40d5806ed528
>> --- /dev/null
>> +++ b/drivers/acpi/arm64/thermal_cpufreq.c
>> @@ -0,0 +1,22 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +#include <linux/acpi.h>
>> +
>> +#include "../internal.h"
>> +
>> +#ifdef CONFIG_HAVE_ARM_SMCCC_DISCOVERY
>> +#define SMCCC_SOC_ID_T241 0x036b0241
>
> Sorry for missing this earlier. Not sure if the above define needs to be
> conditional. Even if it has to be, CONFIG_ARM_SMCCC_SOC_ID is more
> appropriate.
>
Will remove the ifdef.
>> +
>> +int acpi_arch_thermal_cpufreq_pctg(void)
>> +{
>> + s32 soc_id = arm_smccc_get_soc_id_version();
>> +
>> + /*
>> + * Check JEP106 code for NVIDIA Tegra241 chip (036b:0241) and
>> + * reduce the CPUFREQ Thermal reduction percentage to 5%.
>> + */
>> + if (soc_id == SMCCC_SOC_ID_T241)
>> + return 5;
>> +
>> + return 0;
>> +}
>> +#endif
>> diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
>> index 866c7c4ed233..ee213a8cddc5 100644
>> --- a/drivers/acpi/internal.h
>> +++ b/drivers/acpi/internal.h
>> @@ -85,6 +85,15 @@ bool acpi_scan_is_offline(struct acpi_device *adev, bool uevent);
>> acpi_status acpi_sysfs_table_handler(u32 event, void *table, void *context);
>> void acpi_scan_table_notify(void);
>>
>> +#ifdef CONFIG_HAVE_ARM_SMCCC_DISCOVERY
>
> It looks weird to add a such specific ARM config option in generic ACPI
> code/header.
>
> Does it make sense to add some new config this new feature you are adding
> or just use ARM64 and have CONFIG_HAVE_ARM_SMCCC_DISCOVERY check internally
> in the arch specific call.
>
> --
> Regards,
> Sudeep
Ok, will use CONFIG_ARM64 instead.
I think we don't need to check for CONFIG_HAVE_ARM_SMCCC_DISCOVERY
inside the arch call as it returns zero if the soc_id value is different
from Tegra241.
Best Regards,
Sumit Gupta