cpupower: Implement disabling of cstate interface (0924c369) · Commits · e / devices / android_kernel_fairphone_FP5

tools/power/cpupower/utils/helpers/sysfs.c

+115 −1

Original line number	Original line	Diff line number	Diff line
	@@ -87,8 +87,35 @@ int sysfs_is_cpu_online(unsigned int cpu)
	return value;		return value;
	}		}

			/* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */


	/* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */		/* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */

			/*
			* helper function to check whether a file under "../cpuX/cpuidle/stateX/" dir
			* exists.
			* For example the functionality to disable c-states was introduced in later
			* kernel versions, this function can be used to explicitly check for this
			* feature.
			*
			* returns 1 if the file exists, 0 otherwise.
			*/
			unsigned int sysfs_idlestate_file_exists(unsigned int cpu,
			unsigned int idlestate,
			const char *fname)
			{
			char path[SYSFS_PATH_MAX];
			struct stat statbuf;


			snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpuidle/state%u/%s",
			cpu, idlestate, fname);
			if (stat(path, &statbuf) != 0)
			return 0;
			return 1;
			}

	/*		/*
	* helper function to read file from /sys into given buffer		* helper function to read file from /sys into given buffer
	* fname is a relative path under "cpuX/cpuidle/stateX/" dir		* fname is a relative path under "cpuX/cpuidle/stateX/" dir
	@@ -121,6 +148,40 @@ unsigned int sysfs_idlestate_read_file(unsigned int cpu, unsigned int idlestate,
	return (unsigned int) numread;		return (unsigned int) numread;
	}		}

			/*
			* helper function to write a new value to a /sys file
			* fname is a relative path under "../cpuX/cpuidle/cstateY/" dir
			*
			* Returns the number of bytes written or 0 on error
			*/
			static
			unsigned int sysfs_idlestate_write_file(unsigned int cpu,
			unsigned int idlestate,
			const char *fname,
			const char *value, size_t len)
			{
			char path[SYSFS_PATH_MAX];
			int fd;
			ssize_t numwrite;

			snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpuidle/state%u/%s",
			cpu, idlestate, fname);

			fd = open(path, O_WRONLY);
			if (fd == -1)
			return 0;

			numwrite = write(fd, value, len);
			if (numwrite < 1) {
			close(fd);
			return 0;
			}

			close(fd);

			return (unsigned int) numwrite;
			}

	/* read access to files which contain one numeric value */		/* read access to files which contain one numeric value */

	enum idlestate_value {		enum idlestate_value {
	@@ -128,6 +189,7 @@ enum idlestate_value {
	IDLESTATE_POWER,		IDLESTATE_POWER,
	IDLESTATE_LATENCY,		IDLESTATE_LATENCY,
	IDLESTATE_TIME,		IDLESTATE_TIME,
			IDLESTATE_DISABLE,
	MAX_IDLESTATE_VALUE_FILES		MAX_IDLESTATE_VALUE_FILES
	};		};

	@@ -136,6 +198,7 @@ static const char *idlestate_value_files[MAX_IDLESTATE_VALUE_FILES] = {
	[IDLESTATE_POWER] = "power",		[IDLESTATE_POWER] = "power",
	[IDLESTATE_LATENCY] = "latency",		[IDLESTATE_LATENCY] = "latency",
	[IDLESTATE_TIME] = "time",		[IDLESTATE_TIME] = "time",
			[IDLESTATE_DISABLE] = "disable",
	};		};

	static unsigned long long sysfs_idlestate_get_one_value(unsigned int cpu,		static unsigned long long sysfs_idlestate_get_one_value(unsigned int cpu,
	@@ -205,6 +268,57 @@ static char *sysfs_idlestate_get_one_string(unsigned int cpu,
	return result;		return result;
	}		}

			/*
			* Returns:
			* 1 if disabled
			* 0 if enabled
			* -1 if idlestate is not available
			* -2 if disabling is not supported by the kernel
			*/
			int sysfs_is_idlestate_disabled(unsigned int cpu,
			unsigned int idlestate)
			{
			if (sysfs_get_idlestate_count(cpu) < idlestate)
			return -1;

			if (!sysfs_idlestate_file_exists(cpu, idlestate,
			idlestate_value_files[IDLESTATE_DISABLE]))
			return -2;
			return sysfs_idlestate_get_one_value(cpu, idlestate, IDLESTATE_DISABLE);
			}

			/*
			* Pass 1 as last argument to disable or 0 to enable the state
			* Returns:
			* 0 on success
			* negative values on error, for example:
			* -1 if idlestate is not available
			* -2 if disabling is not supported by the kernel
			* -3 No write access to disable/enable C-states
			*/
			int sysfs_idlestate_disable(unsigned int cpu,
			unsigned int idlestate,
			unsigned int disable)
			{
			char value[SYSFS_PATH_MAX];
			int bytes_written;

			if (sysfs_get_idlestate_count(cpu) < idlestate)
			return -1;

			if (!sysfs_idlestate_file_exists(cpu, idlestate,
			idlestate_value_files[IDLESTATE_DISABLE]))
			return -2;

			snprintf(value, SYSFS_PATH_MAX, "%u", disable);

			bytes_written = sysfs_idlestate_write_file(cpu, idlestate, "disable",
			value, sizeof(disable));
			if (bytes_written)
			return 0;
			return -3;
			}

	unsigned long sysfs_get_idlestate_latency(unsigned int cpu,		unsigned long sysfs_get_idlestate_latency(unsigned int cpu,
	unsigned int idlestate)		unsigned int idlestate)
	{		{

tools/power/cpupower/utils/helpers/sysfs.h

+8 −0

Original line number	Original line	Diff line number	Diff line
	@@ -7,8 +7,16 @@

	extern unsigned int sysfs_read_file(const char path, char buf, size_t buflen);		extern unsigned int sysfs_read_file(const char path, char buf, size_t buflen);

			extern unsigned int sysfs_idlestate_file_exists(unsigned int cpu,
			unsigned int idlestate,
			const char *fname);

	extern int sysfs_is_cpu_online(unsigned int cpu);		extern int sysfs_is_cpu_online(unsigned int cpu);

			extern int sysfs_is_idlestate_disabled(unsigned int cpu,
			unsigned int idlestate);
			extern int sysfs_idlestate_disable(unsigned int cpu, unsigned int idlestate,
			unsigned int disable);
	extern unsigned long sysfs_get_idlestate_latency(unsigned int cpu,		extern unsigned long sysfs_get_idlestate_latency(unsigned int cpu,
	unsigned int idlestate);		unsigned int idlestate);
	extern unsigned long sysfs_get_idlestate_usage(unsigned int cpu,		extern unsigned long sysfs_get_idlestate_usage(unsigned int cpu,