Initial commit; kernel source import

tools/power/cpupower/lib/cpufreq.c

@@ -0,0 +1,208 @@
+/*
+ *  (C) 2004-2009  Dominik Brodowski <linux@dominikbrodowski.de>
+ *
+ *  Licensed under the terms of the GNU GPL License version 2.
+ */
+
+
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "cpufreq.h"
+#include "sysfs.h"
+
+int cpufreq_cpu_exists(unsigned int cpu)
+{
+	return sysfs_cpu_exists(cpu);
+}
+
+unsigned long cpufreq_get_freq_kernel(unsigned int cpu)
+{
+	return sysfs_get_freq_kernel(cpu);
+}
+
+unsigned long cpufreq_get_freq_hardware(unsigned int cpu)
+{
+	return sysfs_get_freq_hardware(cpu);
+}
+
+unsigned long cpufreq_get_transition_latency(unsigned int cpu)
+{
+	return sysfs_get_freq_transition_latency(cpu);
+}
+
+int cpufreq_get_hardware_limits(unsigned int cpu,
+				unsigned long *min,
+				unsigned long *max)
+{
+	if ((!min) || (!max))
+		return -EINVAL;
+	return sysfs_get_freq_hardware_limits(cpu, min, max);
+}
+
+char *cpufreq_get_driver(unsigned int cpu)
+{
+	return sysfs_get_freq_driver(cpu);
+}
+
+void cpufreq_put_driver(char *ptr)
+{
+	if (!ptr)
+		return;
+	free(ptr);
+}
+
+struct cpufreq_policy *cpufreq_get_policy(unsigned int cpu)
+{
+	return sysfs_get_freq_policy(cpu);
+}
+
+void cpufreq_put_policy(struct cpufreq_policy *policy)
+{
+	if ((!policy) || (!policy->governor))
+		return;
+
+	free(policy->governor);
+	policy->governor = NULL;
+	free(policy);
+}
+
+struct cpufreq_available_governors *cpufreq_get_available_governors(unsigned
+								int cpu)
+{
+	return sysfs_get_freq_available_governors(cpu);
+}
+
+void cpufreq_put_available_governors(struct cpufreq_available_governors *any)
+{
+	struct cpufreq_available_governors *tmp, *next;
+
+	if (!any)
+		return;
+
+	tmp = any->first;
+	while (tmp) {
+		next = tmp->next;
+		if (tmp->governor)
+			free(tmp->governor);
+		free(tmp);
+		tmp = next;
+	}
+}
+
+
+struct cpufreq_available_frequencies
+*cpufreq_get_available_frequencies(unsigned int cpu)
+{
+	return sysfs_get_available_frequencies(cpu);
+}
+
+void cpufreq_put_available_frequencies(struct cpufreq_available_frequencies
+				*any) {
+	struct cpufreq_available_frequencies *tmp, *next;
+
+	if (!any)
+		return;
+
+	tmp = any->first;
+	while (tmp) {
+		next = tmp->next;
+		free(tmp);
+		tmp = next;
+	}
+}
+
+
+struct cpufreq_affected_cpus *cpufreq_get_affected_cpus(unsigned int cpu)
+{
+	return sysfs_get_freq_affected_cpus(cpu);
+}
+
+void cpufreq_put_affected_cpus(struct cpufreq_affected_cpus *any)
+{
+	struct cpufreq_affected_cpus *tmp, *next;
+
+	if (!any)
+		return;
+
+	tmp = any->first;
+	while (tmp) {
+		next = tmp->next;
+		free(tmp);
+		tmp = next;
+	}
+}
+
+
+struct cpufreq_affected_cpus *cpufreq_get_related_cpus(unsigned int cpu)
+{
+	return sysfs_get_freq_related_cpus(cpu);
+}
+
+void cpufreq_put_related_cpus(struct cpufreq_affected_cpus *any)
+{
+	cpufreq_put_affected_cpus(any);
+}
+
+
+int cpufreq_set_policy(unsigned int cpu, struct cpufreq_policy *policy)
+{
+	if (!policy || !(policy->governor))
+		return -EINVAL;
+
+	return sysfs_set_freq_policy(cpu, policy);
+}
+
+
+int cpufreq_modify_policy_min(unsigned int cpu, unsigned long min_freq)
+{
+	return sysfs_modify_freq_policy_min(cpu, min_freq);
+}
+
+
+int cpufreq_modify_policy_max(unsigned int cpu, unsigned long max_freq)
+{
+	return sysfs_modify_freq_policy_max(cpu, max_freq);
+}
+
+
+int cpufreq_modify_policy_governor(unsigned int cpu, char *governor)
+{
+	if ((!governor) || (strlen(governor) > 19))
+		return -EINVAL;
+
+	return sysfs_modify_freq_policy_governor(cpu, governor);
+}
+
+int cpufreq_set_frequency(unsigned int cpu, unsigned long target_frequency)
+{
+	return sysfs_set_frequency(cpu, target_frequency);
+}
+
+struct cpufreq_stats *cpufreq_get_stats(unsigned int cpu,
+					unsigned long long *total_time)
+{
+	return sysfs_get_freq_stats(cpu, total_time);
+}
+
+void cpufreq_put_stats(struct cpufreq_stats *any)
+{
+	struct cpufreq_stats *tmp, *next;
+
+	if (!any)
+		return;
+
+	tmp = any->first;
+	while (tmp) {
+		next = tmp->next;
+		free(tmp);
+		tmp = next;
+	}
+}
+
+unsigned long cpufreq_get_transitions(unsigned int cpu)
+{
+	return sysfs_get_freq_transitions(cpu);
+}

tools/power/cpupower/lib/cpufreq.h

@@ -0,0 +1,223 @@
+/*
+ *  cpufreq.h - definitions for libcpufreq
+ *
+ *  Copyright (C) 2004-2009  Dominik Brodowski <linux@dominikbrodowski.de>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef _CPUFREQ_H
+#define _CPUFREQ_H 1
+
+struct cpufreq_policy {
+	unsigned long min;
+	unsigned long max;
+	char *governor;
+};
+
+struct cpufreq_available_governors {
+	char *governor;
+	struct cpufreq_available_governors *next;
+	struct cpufreq_available_governors *first;
+};
+
+struct cpufreq_available_frequencies {
+	unsigned long frequency;
+	struct cpufreq_available_frequencies *next;
+	struct cpufreq_available_frequencies *first;
+};
+
+
+struct cpufreq_affected_cpus {
+	unsigned int cpu;
+	struct cpufreq_affected_cpus *next;
+	struct cpufreq_affected_cpus *first;
+};
+
+struct cpufreq_stats {
+	unsigned long frequency;
+	unsigned long long time_in_state;
+	struct cpufreq_stats *next;
+	struct cpufreq_stats *first;
+};
+
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * returns 0 if the specified CPU is present (it doesn't say
+ * whether it is online!), and an error value if not.
+ */
+
+extern int cpufreq_cpu_exists(unsigned int cpu);
+
+/* determine current CPU frequency
+ * - _kernel variant means kernel's opinion of CPU frequency
+ * - _hardware variant means actual hardware CPU frequency,
+ *    which is only available to root.
+ *
+ * returns 0 on failure, else frequency in kHz.
+ */
+
+extern unsigned long cpufreq_get_freq_kernel(unsigned int cpu);
+
+extern unsigned long cpufreq_get_freq_hardware(unsigned int cpu);
+
+#define cpufreq_get(cpu) cpufreq_get_freq_kernel(cpu);
+
+
+/* determine CPU transition latency
+ *
+ * returns 0 on failure, else transition latency in 10^(-9) s = nanoseconds
+ */
+extern unsigned long cpufreq_get_transition_latency(unsigned int cpu);
+
+
+/* determine hardware CPU frequency limits
+ *
+ * These may be limited further by thermal, energy or other
+ * considerations by cpufreq policy notifiers in the kernel.
+ */
+
+extern int cpufreq_get_hardware_limits(unsigned int cpu,
+				unsigned long *min,
+				unsigned long *max);
+
+
+/* determine CPUfreq driver used
+ *
+ * Remember to call cpufreq_put_driver when no longer needed
+ * to avoid memory leakage, please.
+ */
+
+extern char *cpufreq_get_driver(unsigned int cpu);
+
+extern void cpufreq_put_driver(char *ptr);
+
+
+/* determine CPUfreq policy currently used
+ *
+ * Remember to call cpufreq_put_policy when no longer needed
+ * to avoid memory leakage, please.
+ */
+
+
+extern struct cpufreq_policy *cpufreq_get_policy(unsigned int cpu);
+
+extern void cpufreq_put_policy(struct cpufreq_policy *policy);
+
+
+/* determine CPUfreq governors currently available
+ *
+ * may be modified by modprobe'ing or rmmod'ing other governors. Please
+ * free allocated memory by calling cpufreq_put_available_governors
+ * after use.
+ */
+
+
+extern struct cpufreq_available_governors
+*cpufreq_get_available_governors(unsigned int cpu);
+
+extern void cpufreq_put_available_governors(
+	struct cpufreq_available_governors *first);
+
+
+/* determine CPU frequency states available
+ *
+ * Only present on _some_ ->target() cpufreq drivers. For information purposes
+ * only. Please free allocated memory by calling
+ * cpufreq_put_available_frequencies after use.
+ */
+
+extern struct cpufreq_available_frequencies
+*cpufreq_get_available_frequencies(unsigned int cpu);
+
+extern void cpufreq_put_available_frequencies(
+		struct cpufreq_available_frequencies *first);
+
+
+/* determine affected CPUs
+ *
+ * Remember to call cpufreq_put_affected_cpus when no longer needed
+ * to avoid memory leakage, please.
+ */
+
+extern struct cpufreq_affected_cpus *cpufreq_get_affected_cpus(unsigned
+							int cpu);
+
+extern void cpufreq_put_affected_cpus(struct cpufreq_affected_cpus *first);
+
+
+/* determine related CPUs
+ *
+ * Remember to call cpufreq_put_related_cpus when no longer needed
+ * to avoid memory leakage, please.
+ */
+
+extern struct cpufreq_affected_cpus *cpufreq_get_related_cpus(unsigned
+							int cpu);
+
+extern void cpufreq_put_related_cpus(struct cpufreq_affected_cpus *first);
+
+
+/* determine stats for cpufreq subsystem
+ *
+ * This is not available in all kernel versions or configurations.
+ */
+
+extern struct cpufreq_stats *cpufreq_get_stats(unsigned int cpu,
+					unsigned long long *total_time);
+
+extern void cpufreq_put_stats(struct cpufreq_stats *stats);
+
+extern unsigned long cpufreq_get_transitions(unsigned int cpu);
+
+
+/* set new cpufreq policy
+ *
+ * Tries to set the passed policy as new policy as close as possible,
+ * but results may differ depending e.g. on governors being available.
+ */
+
+extern int cpufreq_set_policy(unsigned int cpu, struct cpufreq_policy *policy);
+
+
+/* modify a policy by only changing min/max freq or governor
+ *
+ * Does not check whether result is what was intended.
+ */
+
+extern int cpufreq_modify_policy_min(unsigned int cpu, unsigned long min_freq);
+extern int cpufreq_modify_policy_max(unsigned int cpu, unsigned long max_freq);
+extern int cpufreq_modify_policy_governor(unsigned int cpu, char *governor);
+
+
+/* set a specific frequency
+ *
+ * Does only work if userspace governor can be used and no external
+ * interference (other calls to this function or to set/modify_policy)
+ * occurs. Also does not work on ->range() cpufreq drivers.
+ */
+
+extern int cpufreq_set_frequency(unsigned int cpu,
+				unsigned long target_frequency);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _CPUFREQ_H */

tools/power/cpupower/lib/sysfs.c

@@ -0,0 +1,672 @@
+/*
+ *  (C) 2004-2009  Dominik Brodowski <linux@dominikbrodowski.de>
+ *
+ *  Licensed under the terms of the GNU GPL License version 2.
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "cpufreq.h"
+
+#define PATH_TO_CPU "/sys/devices/system/cpu/"
+#define MAX_LINE_LEN 4096
+#define SYSFS_PATH_MAX 255
+
+
+static unsigned int sysfs_read_file(const char *path, char *buf, size_t buflen)
+{
+	int fd;
+	ssize_t numread;
+
+	fd = open(path, O_RDONLY);
+	if (fd == -1)
+		return 0;
+
+	numread = read(fd, buf, buflen - 1);
+	if (numread < 1) {
+		close(fd);
+		return 0;
+	}
+
+	buf[numread] = '\0';
+	close(fd);
+
+	return (unsigned int) numread;
+}
+
+
+/* CPUFREQ sysfs access **************************************************/
+
+/* helper function to read file from /sys into given buffer */
+/* fname is a relative path under "cpuX/cpufreq" dir */
+static unsigned int sysfs_cpufreq_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/cpufreq/%s",
+			 cpu, fname);
+	return sysfs_read_file(path, buf, buflen);
+}
+
+/* helper function to write a new value to a /sys file */
+/* fname is a relative path under "cpuX/cpufreq" dir */
+static unsigned int sysfs_cpufreq_write_file(unsigned int cpu,
+					     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/cpufreq/%s",
+			 cpu, 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 */
+
+enum cpufreq_value {
+	CPUINFO_CUR_FREQ,
+	CPUINFO_MIN_FREQ,
+	CPUINFO_MAX_FREQ,
+	CPUINFO_LATENCY,
+	SCALING_CUR_FREQ,
+	SCALING_MIN_FREQ,
+	SCALING_MAX_FREQ,
+	STATS_NUM_TRANSITIONS,
+	MAX_CPUFREQ_VALUE_READ_FILES
+};
+
+static const char *cpufreq_value_files[MAX_CPUFREQ_VALUE_READ_FILES] = {
+	[CPUINFO_CUR_FREQ] = "cpuinfo_cur_freq",
+	[CPUINFO_MIN_FREQ] = "cpuinfo_min_freq",
+	[CPUINFO_MAX_FREQ] = "cpuinfo_max_freq",
+	[CPUINFO_LATENCY]  = "cpuinfo_transition_latency",
+	[SCALING_CUR_FREQ] = "scaling_cur_freq",
+	[SCALING_MIN_FREQ] = "scaling_min_freq",
+	[SCALING_MAX_FREQ] = "scaling_max_freq",
+	[STATS_NUM_TRANSITIONS] = "stats/total_trans"
+};
+
+
+static unsigned long sysfs_cpufreq_get_one_value(unsigned int cpu,
+						 enum cpufreq_value which)
+{
+	unsigned long value;
+	unsigned int len;
+	char linebuf[MAX_LINE_LEN];
+	char *endp;
+
+	if (which >= MAX_CPUFREQ_VALUE_READ_FILES)
+		return 0;
+
+	len = sysfs_cpufreq_read_file(cpu, cpufreq_value_files[which],
+				linebuf, sizeof(linebuf));
+
+	if (len == 0)
+		return 0;
+
+	value = strtoul(linebuf, &endp, 0);
+
+	if (endp == linebuf || errno == ERANGE)
+		return 0;
+
+	return value;
+}
+
+/* read access to files which contain one string */
+
+enum cpufreq_string {
+	SCALING_DRIVER,
+	SCALING_GOVERNOR,
+	MAX_CPUFREQ_STRING_FILES
+};
+
+static const char *cpufreq_string_files[MAX_CPUFREQ_STRING_FILES] = {
+	[SCALING_DRIVER] = "scaling_driver",
+	[SCALING_GOVERNOR] = "scaling_governor",
+};
+
+
+static char *sysfs_cpufreq_get_one_string(unsigned int cpu,
+					   enum cpufreq_string which)
+{
+	char linebuf[MAX_LINE_LEN];
+	char *result;
+	unsigned int len;
+
+	if (which >= MAX_CPUFREQ_STRING_FILES)
+		return NULL;
+
+	len = sysfs_cpufreq_read_file(cpu, cpufreq_string_files[which],
+				linebuf, sizeof(linebuf));
+	if (len == 0)
+		return NULL;
+
+	result = strdup(linebuf);
+	if (result == NULL)
+		return NULL;
+
+	if (result[strlen(result) - 1] == '\n')
+		result[strlen(result) - 1] = '\0';
+
+	return result;
+}
+
+/* write access */
+
+enum cpufreq_write {
+	WRITE_SCALING_MIN_FREQ,
+	WRITE_SCALING_MAX_FREQ,
+	WRITE_SCALING_GOVERNOR,
+	WRITE_SCALING_SET_SPEED,
+	MAX_CPUFREQ_WRITE_FILES
+};
+
+static const char *cpufreq_write_files[MAX_CPUFREQ_WRITE_FILES] = {
+	[WRITE_SCALING_MIN_FREQ] = "scaling_min_freq",
+	[WRITE_SCALING_MAX_FREQ] = "scaling_max_freq",
+	[WRITE_SCALING_GOVERNOR] = "scaling_governor",
+	[WRITE_SCALING_SET_SPEED] = "scaling_setspeed",
+};
+
+static int sysfs_cpufreq_write_one_value(unsigned int cpu,
+					 enum cpufreq_write which,
+					 const char *new_value, size_t len)
+{
+	if (which >= MAX_CPUFREQ_WRITE_FILES)
+		return 0;
+
+	if (sysfs_cpufreq_write_file(cpu, cpufreq_write_files[which],
+					new_value, len) != len)
+		return -ENODEV;
+
+	return 0;
+};
+
+unsigned long sysfs_get_freq_kernel(unsigned int cpu)
+{
+	return sysfs_cpufreq_get_one_value(cpu, SCALING_CUR_FREQ);
+}
+
+unsigned long sysfs_get_freq_hardware(unsigned int cpu)
+{
+	return sysfs_cpufreq_get_one_value(cpu, CPUINFO_CUR_FREQ);
+}
+
+unsigned long sysfs_get_freq_transition_latency(unsigned int cpu)
+{
+	return sysfs_cpufreq_get_one_value(cpu, CPUINFO_LATENCY);
+}
+
+int sysfs_get_freq_hardware_limits(unsigned int cpu,
+			      unsigned long *min,
+			      unsigned long *max)
+{
+	if ((!min) || (!max))
+		return -EINVAL;
+
+	*min = sysfs_cpufreq_get_one_value(cpu, CPUINFO_MIN_FREQ);
+	if (!*min)
+		return -ENODEV;
+
+	*max = sysfs_cpufreq_get_one_value(cpu, CPUINFO_MAX_FREQ);
+	if (!*max)
+		return -ENODEV;
+
+	return 0;
+}
+
+char *sysfs_get_freq_driver(unsigned int cpu)
+{
+	return sysfs_cpufreq_get_one_string(cpu, SCALING_DRIVER);
+}
+
+struct cpufreq_policy *sysfs_get_freq_policy(unsigned int cpu)
+{
+	struct cpufreq_policy *policy;
+
+	policy = malloc(sizeof(struct cpufreq_policy));
+	if (!policy)
+		return NULL;
+
+	policy->governor = sysfs_cpufreq_get_one_string(cpu, SCALING_GOVERNOR);
+	if (!policy->governor) {
+		free(policy);
+		return NULL;
+	}
+	policy->min = sysfs_cpufreq_get_one_value(cpu, SCALING_MIN_FREQ);
+	policy->max = sysfs_cpufreq_get_one_value(cpu, SCALING_MAX_FREQ);
+	if ((!policy->min) || (!policy->max)) {
+		free(policy->governor);
+		free(policy);
+		return NULL;
+	}
+
+	return policy;
+}
+
+struct cpufreq_available_governors *
+sysfs_get_freq_available_governors(unsigned int cpu) {
+	struct cpufreq_available_governors *first = NULL;
+	struct cpufreq_available_governors *current = NULL;
+	char linebuf[MAX_LINE_LEN];
+	unsigned int pos, i;
+	unsigned int len;
+
+	len = sysfs_cpufreq_read_file(cpu, "scaling_available_governors",
+				linebuf, sizeof(linebuf));
+	if (len == 0)
+		return NULL;
+
+	pos = 0;
+	for (i = 0; i < len; i++) {
+		if (linebuf[i] == ' ' || linebuf[i] == '\n') {
+			if (i - pos < 2)
+				continue;
+			if (current) {
+				current->next = malloc(sizeof(*current));
+				if (!current->next)
+					goto error_out;
+				current = current->next;
+			} else {
+				first = malloc(sizeof(*first));
+				if (!first)
+					goto error_out;
+				current = first;
+			}
+			current->first = first;
+			current->next = NULL;
+
+			current->governor = malloc(i - pos + 1);
+			if (!current->governor)
+				goto error_out;
+
+			memcpy(current->governor, linebuf + pos, i - pos);
+			current->governor[i - pos] = '\0';
+			pos = i + 1;
+		}
+	}
+
+	return first;
+
+ error_out:
+	while (first) {
+		current = first->next;
+		if (first->governor)
+			free(first->governor);
+		free(first);
+		first = current;
+	}
+	return NULL;
+}
+
+
+struct cpufreq_available_frequencies *
+sysfs_get_available_frequencies(unsigned int cpu) {
+	struct cpufreq_available_frequencies *first = NULL;
+	struct cpufreq_available_frequencies *current = NULL;
+	char one_value[SYSFS_PATH_MAX];
+	char linebuf[MAX_LINE_LEN];
+	unsigned int pos, i;
+	unsigned int len;
+
+	len = sysfs_cpufreq_read_file(cpu, "scaling_available_frequencies",
+				linebuf, sizeof(linebuf));
+	if (len == 0)
+		return NULL;
+
+	pos = 0;
+	for (i = 0; i < len; i++) {
+		if (linebuf[i] == ' ' || linebuf[i] == '\n') {
+			if (i - pos < 2)
+				continue;
+			if (i - pos >= SYSFS_PATH_MAX)
+				goto error_out;
+			if (current) {
+				current->next = malloc(sizeof(*current));
+				if (!current->next)
+					goto error_out;
+				current = current->next;
+			} else {
+				first = malloc(sizeof(*first));
+				if (!first)
+					goto error_out;
+				current = first;
+			}
+			current->first = first;
+			current->next = NULL;
+
+			memcpy(one_value, linebuf + pos, i - pos);
+			one_value[i - pos] = '\0';
+			if (sscanf(one_value, "%lu", &current->frequency) != 1)
+				goto error_out;
+
+			pos = i + 1;
+		}
+	}
+
+	return first;
+
+ error_out:
+	while (first) {
+		current = first->next;
+		free(first);
+		first = current;
+	}
+	return NULL;
+}
+
+static struct cpufreq_affected_cpus *sysfs_get_cpu_list(unsigned int cpu,
+							const char *file)
+{
+	struct cpufreq_affected_cpus *first = NULL;
+	struct cpufreq_affected_cpus *current = NULL;
+	char one_value[SYSFS_PATH_MAX];
+	char linebuf[MAX_LINE_LEN];
+	unsigned int pos, i;
+	unsigned int len;
+
+	len = sysfs_cpufreq_read_file(cpu, file, linebuf, sizeof(linebuf));
+	if (len == 0)
+		return NULL;
+
+	pos = 0;
+	for (i = 0; i < len; i++) {
+		if (i == len || linebuf[i] == ' ' || linebuf[i] == '\n') {
+			if (i - pos  < 1)
+				continue;
+			if (i - pos >= SYSFS_PATH_MAX)
+				goto error_out;
+			if (current) {
+				current->next = malloc(sizeof(*current));
+				if (!current->next)
+					goto error_out;
+				current = current->next;
+			} else {
+				first = malloc(sizeof(*first));
+				if (!first)
+					goto error_out;
+				current = first;
+			}
+			current->first = first;
+			current->next = NULL;
+
+			memcpy(one_value, linebuf + pos, i - pos);
+			one_value[i - pos] = '\0';
+
+			if (sscanf(one_value, "%u", &current->cpu) != 1)
+				goto error_out;
+
+			pos = i + 1;
+		}
+	}
+
+	return first;
+
+ error_out:
+	while (first) {
+		current = first->next;
+		free(first);
+		first = current;
+	}
+	return NULL;
+}
+
+struct cpufreq_affected_cpus *sysfs_get_freq_affected_cpus(unsigned int cpu)
+{
+	return sysfs_get_cpu_list(cpu, "affected_cpus");
+}
+
+struct cpufreq_affected_cpus *sysfs_get_freq_related_cpus(unsigned int cpu)
+{
+	return sysfs_get_cpu_list(cpu, "related_cpus");
+}
+
+struct cpufreq_stats *sysfs_get_freq_stats(unsigned int cpu,
+					unsigned long long *total_time) {
+	struct cpufreq_stats *first = NULL;
+	struct cpufreq_stats *current = NULL;
+	char one_value[SYSFS_PATH_MAX];
+	char linebuf[MAX_LINE_LEN];
+	unsigned int pos, i;
+	unsigned int len;
+
+	len = sysfs_cpufreq_read_file(cpu, "stats/time_in_state",
+				linebuf, sizeof(linebuf));
+	if (len == 0)
+		return NULL;
+
+	*total_time = 0;
+	pos = 0;
+	for (i = 0; i < len; i++) {
+		if (i == strlen(linebuf) || linebuf[i] == '\n')	{
+			if (i - pos < 2)
+				continue;
+			if ((i - pos) >= SYSFS_PATH_MAX)
+				goto error_out;
+			if (current) {
+				current->next = malloc(sizeof(*current));
+				if (!current->next)
+					goto error_out;
+				current = current->next;
+			} else {
+				first = malloc(sizeof(*first));
+				if (!first)
+					goto error_out;
+				current = first;
+			}
+			current->first = first;
+			current->next = NULL;
+
+			memcpy(one_value, linebuf + pos, i - pos);
+			one_value[i - pos] = '\0';
+			if (sscanf(one_value, "%lu %llu",
+					&current->frequency,
+					&current->time_in_state) != 2)
+				goto error_out;
+
+			*total_time = *total_time + current->time_in_state;
+			pos = i + 1;
+		}
+	}
+
+	return first;
+
+ error_out:
+	while (first) {
+		current = first->next;
+		free(first);
+		first = current;
+	}
+	return NULL;
+}
+
+unsigned long sysfs_get_freq_transitions(unsigned int cpu)
+{
+	return sysfs_cpufreq_get_one_value(cpu, STATS_NUM_TRANSITIONS);
+}
+
+static int verify_gov(char *new_gov, char *passed_gov)
+{
+	unsigned int i, j = 0;
+
+	if (!passed_gov || (strlen(passed_gov) > 19))
+		return -EINVAL;
+
+	strncpy(new_gov, passed_gov, 20);
+	for (i = 0; i < 20; i++) {
+		if (j) {
+			new_gov[i] = '\0';
+			continue;
+		}
+		if ((new_gov[i] >= 'a') && (new_gov[i] <= 'z'))
+			continue;
+
+		if ((new_gov[i] >= 'A') && (new_gov[i] <= 'Z'))
+			continue;
+
+		if (new_gov[i] == '-')
+			continue;
+
+		if (new_gov[i] == '_')
+			continue;
+
+		if (new_gov[i] == '\0') {
+			j = 1;
+			continue;
+		}
+		return -EINVAL;
+	}
+	new_gov[19] = '\0';
+	return 0;
+}
+
+int sysfs_modify_freq_policy_governor(unsigned int cpu, char *governor)
+{
+	char new_gov[SYSFS_PATH_MAX];
+
+	if (!governor)
+		return -EINVAL;
+
+	if (verify_gov(new_gov, governor))
+		return -EINVAL;
+
+	return sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_GOVERNOR,
+					     new_gov, strlen(new_gov));
+};
+
+int sysfs_modify_freq_policy_max(unsigned int cpu, unsigned long max_freq)
+{
+	char value[SYSFS_PATH_MAX];
+
+	snprintf(value, SYSFS_PATH_MAX, "%lu", max_freq);
+
+	return sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_MAX_FREQ,
+					     value, strlen(value));
+};
+
+
+int sysfs_modify_freq_policy_min(unsigned int cpu, unsigned long min_freq)
+{
+	char value[SYSFS_PATH_MAX];
+
+	snprintf(value, SYSFS_PATH_MAX, "%lu", min_freq);
+
+	return sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_MIN_FREQ,
+					     value, strlen(value));
+};
+
+
+int sysfs_set_freq_policy(unsigned int cpu, struct cpufreq_policy *policy)
+{
+	char min[SYSFS_PATH_MAX];
+	char max[SYSFS_PATH_MAX];
+	char gov[SYSFS_PATH_MAX];
+	int ret;
+	unsigned long old_min;
+	int write_max_first;
+
+	if (!policy || !(policy->governor))
+		return -EINVAL;
+
+	if (policy->max < policy->min)
+		return -EINVAL;
+
+	if (verify_gov(gov, policy->governor))
+		return -EINVAL;
+
+	snprintf(min, SYSFS_PATH_MAX, "%lu", policy->min);
+	snprintf(max, SYSFS_PATH_MAX, "%lu", policy->max);
+
+	old_min = sysfs_cpufreq_get_one_value(cpu, SCALING_MIN_FREQ);
+	write_max_first = (old_min && (policy->max < old_min) ? 0 : 1);
+
+	if (write_max_first) {
+		ret = sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_MAX_FREQ,
+						    max, strlen(max));
+		if (ret)
+			return ret;
+	}
+
+	ret = sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_MIN_FREQ, min,
+					    strlen(min));
+	if (ret)
+		return ret;
+
+	if (!write_max_first) {
+		ret = sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_MAX_FREQ,
+						    max, strlen(max));
+		if (ret)
+			return ret;
+	}
+
+	return sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_GOVERNOR,
+					     gov, strlen(gov));
+}
+
+int sysfs_set_frequency(unsigned int cpu, unsigned long target_frequency)
+{
+	struct cpufreq_policy *pol = sysfs_get_freq_policy(cpu);
+	char userspace_gov[] = "userspace";
+	char freq[SYSFS_PATH_MAX];
+	int ret;
+
+	if (!pol)
+		return -ENODEV;
+
+	if (strncmp(pol->governor, userspace_gov, 9) != 0) {
+		ret = sysfs_modify_freq_policy_governor(cpu, userspace_gov);
+		if (ret) {
+			cpufreq_put_policy(pol);
+			return ret;
+		}
+	}
+
+	cpufreq_put_policy(pol);
+
+	snprintf(freq, SYSFS_PATH_MAX, "%lu", target_frequency);
+
+	return sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_SET_SPEED,
+					     freq, strlen(freq));
+}
+
+/* CPUFREQ sysfs access **************************************************/
+
+/* General sysfs access **************************************************/
+int sysfs_cpu_exists(unsigned int cpu)
+{
+	char file[SYSFS_PATH_MAX];
+	struct stat statbuf;
+
+	snprintf(file, SYSFS_PATH_MAX, PATH_TO_CPU "cpu%u/", cpu);
+
+	if (stat(file, &statbuf) != 0)
+		return -ENOSYS;
+
+	return S_ISDIR(statbuf.st_mode) ? 0 : -ENOSYS;
+}
+
+/* General sysfs access **************************************************/

tools/power/cpupower/lib/sysfs.h

@@ -0,0 +1,31 @@
+/* General */
+extern unsigned int sysfs_cpu_exists(unsigned int cpu);
+
+/* CPUfreq */
+extern unsigned long sysfs_get_freq_kernel(unsigned int cpu);
+extern unsigned long sysfs_get_freq_hardware(unsigned int cpu);
+extern unsigned long sysfs_get_freq_transition_latency(unsigned int cpu);
+extern int sysfs_get_freq_hardware_limits(unsigned int cpu,
+					unsigned long *min, unsigned long *max);
+extern char *sysfs_get_freq_driver(unsigned int cpu);
+extern struct cpufreq_policy *sysfs_get_freq_policy(unsigned int cpu);
+extern struct cpufreq_available_governors *sysfs_get_freq_available_governors(
+	unsigned int cpu);
+extern struct cpufreq_available_frequencies *sysfs_get_available_frequencies(
+	unsigned int cpu);
+extern struct cpufreq_affected_cpus *sysfs_get_freq_affected_cpus(
+	unsigned int cpu);
+extern struct cpufreq_affected_cpus *sysfs_get_freq_related_cpus(
+	unsigned int cpu);
+extern struct cpufreq_stats *sysfs_get_freq_stats(unsigned int cpu,
+						unsigned long long *total_time);
+extern unsigned long sysfs_get_freq_transitions(unsigned int cpu);
+extern int sysfs_set_freq_policy(unsigned int cpu,
+				struct cpufreq_policy *policy);
+extern int sysfs_modify_freq_policy_min(unsigned int cpu,
+					unsigned long min_freq);
+extern int sysfs_modify_freq_policy_max(unsigned int cpu,
+					unsigned long max_freq);
+extern int sysfs_modify_freq_policy_governor(unsigned int cpu, char *governor);
+extern int sysfs_set_frequency(unsigned int cpu,
+			unsigned long target_frequency);