On Sat, Oct 14, 2023 at 04:24:26PM +0530, Sumit Gupta wrote:
> From: Srikar Srimath Tirumala <srikars@xxxxxxxxxx>
>
> 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 <srikars@xxxxxxxxxx>
> Co-developed-by: Sumit Gupta <sumitg@xxxxxxxxxx>
> Signed-off-by: Sumit Gupta <sumitg@xxxxxxxxxx>
> ---
> drivers/acpi/arm64/Makefile | 1 +
> drivers/acpi/arm64/thermal_cpufreq.c | 20 ++++++++++++++++
> drivers/acpi/processor_thermal.c | 35 +++++++++++++++++++++++++---
> include/linux/acpi.h | 9 +++++++
> 4 files changed, 62 insertions(+), 3 deletions(-)
> create mode 100644 drivers/acpi/arm64/thermal_cpufreq.c
>
> diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile
> index 143debc1ba4a..3f181d8156cc 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-$(CONFIG_ARM_AMBA) += amba.o
> obj-y += dma.o init.o
> +obj-$(CONFIG_ACPI) += thermal_cpufreq.o
Do we really need CONFIG_ACPI here ? We won't be building this if it
is not enabled.
If this is for some module building, then does it make sense to have
more specific config ? May be CONFIG_ACPI_THERMAL ?
> diff --git a/drivers/acpi/arm64/thermal_cpufreq.c b/drivers/acpi/arm64/thermal_cpufreq.c
> new file mode 100644
> index 000000000000..de834fb013e7
> --- /dev/null
> +++ b/drivers/acpi/arm64/thermal_cpufreq.c
> @@ -0,0 +1,20 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +#include <linux/acpi.h>
> +
> +#ifdef CONFIG_HAVE_ARM_SMCCC_DISCOVERY
> +#define SMCCC_SOC_ID_T241 0x036b0241
> +
> +int acpi_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
Since this looks like arch specific hook/callback, not sure if it is good
idea to have "arch_" in the function name. But if Rafael is OK with the name
I am fine with this as well.
--
Regards,
Sudeep
