1 // SPDX-License-Identifier: GPL-2.0-only
3  *  (C) 2004-2009  Dominik Brodowski <linux@dominikbrodowski.de>
22  * For example the functionality to disable c-states was introduced in later
29 unsigned int cpuidle_state_file_exists(unsigned int cpu,  in cpuidle_state_file_exists()  argument
37 	snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpuidle/state%u/%s",  in cpuidle_state_file_exists()
38 		 cpu, idlestate, fname);  in cpuidle_state_file_exists()
45  * helper function to read file from /sys into given buffer
51 unsigned int cpuidle_state_read_file(unsigned int cpu,  in cpuidle_state_read_file()  argument
60 	snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpuidle/state%u/%s",  in cpuidle_state_read_file()
61 		 cpu, idlestate, fname);  in cpuidle_state_read_file()
64 	if (fd == -1)  in cpuidle_state_read_file()
67 	numread = read(fd, buf, buflen - 1);  in cpuidle_state_read_file()
86 unsigned int cpuidle_state_write_file(unsigned int cpu,  in cpuidle_state_write_file()  argument
95 	snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpuidle/state%u/%s",  in cpuidle_state_write_file()
96 		 cpu, idlestate, fname);  in cpuidle_state_write_file()
99 	if (fd == -1)  in cpuidle_state_write_file()
113 /* read access to files which contain one numeric value */
133 unsigned long long cpuidle_state_get_one_value(unsigned int cpu,  in cpuidle_state_get_one_value()  argument
145 	len = cpuidle_state_read_file(cpu, idlestate,  in cpuidle_state_get_one_value()
159 /* read access to files which contain one string */
173 static char *cpuidle_state_get_one_string(unsigned int cpu,  in cpuidle_state_get_one_string()  argument
184 	len = cpuidle_state_read_file(cpu, idlestate,  in cpuidle_state_get_one_string()
194 	if (result[strlen(result) - 1] == '\n')  in cpuidle_state_get_one_string()
195 		result[strlen(result) - 1] = '\0';  in cpuidle_state_get_one_string()
204  *    -1 if idlestate is not available
205  *    -2 if disabling is not supported by the kernel
207 int cpuidle_is_state_disabled(unsigned int cpu,  in cpuidle_is_state_disabled()  argument
210 	if (cpuidle_state_count(cpu) <= idlestate)  in cpuidle_is_state_disabled()
211 		return -1;  in cpuidle_is_state_disabled()
213 	if (!cpuidle_state_file_exists(cpu, idlestate,  in cpuidle_is_state_disabled()
215 		return -2;  in cpuidle_is_state_disabled()
216 	return cpuidle_state_get_one_value(cpu, idlestate, IDLESTATE_DISABLE);  in cpuidle_is_state_disabled()
224  *      -1 if idlestate is not available
225  *      -2 if disabling is not supported by the kernel
226  *      -3 No write access to disable/enable C-states
228 int cpuidle_state_disable(unsigned int cpu,  in cpuidle_state_disable()  argument
235 	if (cpuidle_state_count(cpu) <= idlestate)  in cpuidle_state_disable()
236 		return -1;  in cpuidle_state_disable()
238 	if (!cpuidle_state_file_exists(cpu, idlestate,  in cpuidle_state_disable()
240 		return -2;  in cpuidle_state_disable()
244 	bytes_written = cpuidle_state_write_file(cpu, idlestate, "disable",  in cpuidle_state_disable()
248 	return -3;  in cpuidle_state_disable()
251 unsigned long cpuidle_state_latency(unsigned int cpu,  in cpuidle_state_latency()  argument
254 	return cpuidle_state_get_one_value(cpu, idlestate, IDLESTATE_LATENCY);  in cpuidle_state_latency()
257 unsigned long cpuidle_state_usage(unsigned int cpu,  in cpuidle_state_usage()  argument
260 	return cpuidle_state_get_one_value(cpu, idlestate, IDLESTATE_USAGE);  in cpuidle_state_usage()
263 unsigned long long cpuidle_state_time(unsigned int cpu,  in cpuidle_state_time()  argument
266 	return cpuidle_state_get_one_value(cpu, idlestate, IDLESTATE_TIME);  in cpuidle_state_time()
269 char *cpuidle_state_name(unsigned int cpu, unsigned int idlestate)  in cpuidle_state_name()  argument
271 	return cpuidle_state_get_one_string(cpu, idlestate, IDLESTATE_NAME);  in cpuidle_state_name()
274 char *cpuidle_state_desc(unsigned int cpu, unsigned int idlestate)  in cpuidle_state_desc()  argument
276 	return cpuidle_state_get_one_string(cpu, idlestate, IDLESTATE_DESC);  in cpuidle_state_desc()
280  * Returns number of supported C-states of CPU core cpu
282  * Zero if cpuidle does not export any C-states
284 unsigned int cpuidle_state_count(unsigned int cpu)  in cpuidle_state_count()  argument
295 	snprintf(file, SYSFS_PATH_MAX, PATH_TO_CPU "cpu%u/cpuidle/state0", cpu);  in cpuidle_state_count()
301 			 "cpu%u/cpuidle/state%d", cpu, idlestates);  in cpuidle_state_count()
304 	idlestates--;  in cpuidle_state_count()
308 /* CPUidle general /sys/devices/system/cpu/cpuidle/ sysfs access ********/
311  * helper function to read file from /sys into given buffer
312  * fname is a relative path under "cpu/cpuidle/" dir
326 /* read access to files which contain one string */
360 	if (result[strlen(result) - 1] == '\n')  in sysfs_cpuidle_get_one_string()
361 		result[strlen(result) - 1] = '\0';  in sysfs_cpuidle_get_one_string()
379 /* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */