Commit 4a06806e authored by Huang Rui's avatar Huang Rui Committed by Shuah Khan
Browse files

cpupower: Introduce ACPI CPPC library 



Kernel ACPI subsytem introduced the sysfs attributes for acpi cppc
library in below path:

/sys/devices/system/cpu/cpuX/acpi_cppc/

And these attributes will be used for AMD P-State driver to provide some
performance and frequency values.

Reviewed-by: default avatarShuah Khan <skhan@linuxfoundation.org>
Signed-off-by: default avatarHuang Rui <ray.huang@amd.com>
Signed-off-by: default avatarShuah Khan <skhan@linuxfoundation.org>
parent e3ede976

tools/power/cpupower/Makefile

+3 −3
Original line number Diff line number Diff line
@@ -143,9 +143,9 @@ UTIL_HEADERS = utils/helpers/helpers.h utils/idle_monitor/cpupower-monitor.h \ 
	utils/helpers/bitmask.h \

	utils/idle_monitor/idle_monitors.h utils/idle_monitor/idle_monitors.def



LIB_HEADERS = 	lib/cpufreq.h lib/cpupower.h lib/cpuidle.h

LIB_SRC = 	lib/cpufreq.c lib/cpupower.c lib/cpuidle.c

LIB_OBJS = 	lib/cpufreq.o lib/cpupower.o lib/cpuidle.o

LIB_HEADERS = 	lib/cpufreq.h lib/cpupower.h lib/cpuidle.h lib/acpi_cppc.h

LIB_SRC = 	lib/cpufreq.c lib/cpupower.c lib/cpuidle.c lib/acpi_cppc.c

LIB_OBJS = 	lib/cpufreq.o lib/cpupower.o lib/cpuidle.o lib/acpi_cppc.o

LIB_OBJS :=	$(addprefix $(OUTPUT),$(LIB_OBJS))



override CFLAGS +=	-pipe

tools/power/cpupower/lib/acpi_cppc.c

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// SPDX-License-Identifier: GPL-2.0-only



#include <stdio.h>

#include <errno.h>

#include <stdlib.h>

#include <string.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <unistd.h>



#include "cpupower_intern.h"

#include "acpi_cppc.h"



/* ACPI CPPC sysfs access ***********************************************/



static int acpi_cppc_read_file(unsigned int cpu, const char *fname,

			       char *buf, size_t buflen)

{

	char path[SYSFS_PATH_MAX];



	snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/acpi_cppc/%s",

		 cpu, fname);

	return cpupower_read_sysfs(path, buf, buflen);

}



static const char * const acpi_cppc_value_files[] = {

	[HIGHEST_PERF] = "highest_perf",

	[LOWEST_PERF] = "lowest_perf",

	[NOMINAL_PERF] = "nominal_perf",

	[LOWEST_NONLINEAR_PERF] = "lowest_nonlinear_perf",

	[LOWEST_FREQ] = "lowest_freq",

	[NOMINAL_FREQ] = "nominal_freq",

	[REFERENCE_PERF] = "reference_perf",

	[WRAPAROUND_TIME] = "wraparound_time"

};



unsigned long acpi_cppc_get_data(unsigned int cpu, enum acpi_cppc_value which)

{

	unsigned long long value;

	unsigned int len;

	char linebuf[MAX_LINE_LEN];

	char *endp;



	if (which >= MAX_CPPC_VALUE_FILES)

		return 0;



	len = acpi_cppc_read_file(cpu, acpi_cppc_value_files[which],

				  linebuf, sizeof(linebuf));

	if (len == 0)

		return 0;



	value = strtoull(linebuf, &endp, 0);



	if (endp == linebuf || errno == ERANGE)

		return 0;



	return value;

}

tools/power/cpupower/lib/acpi_cppc.h

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/* SPDX-License-Identifier: GPL-2.0-only */



#ifndef __ACPI_CPPC_H__

#define __ACPI_CPPC_H__



enum acpi_cppc_value {

	HIGHEST_PERF,

	LOWEST_PERF,

	NOMINAL_PERF,

	LOWEST_NONLINEAR_PERF,

	LOWEST_FREQ,

	NOMINAL_FREQ,

	REFERENCE_PERF,

	WRAPAROUND_TIME,

	MAX_CPPC_VALUE_FILES

};



unsigned long acpi_cppc_get_data(unsigned int cpu,

				 enum acpi_cppc_value which);



#endif /* _ACPI_CPPC_H */