xref: /linux/drivers/cpuidle/sysfs.c (revision b43ab901d671e3e3cad425ea5e9a3c74e266dcdd) 
1 /*
2  * sysfs.c - sysfs support
3  *
4  * (C) 2006-2007 Shaohua Li <shaohua.li@intel.com>
5  *
6  * This code is licenced under the GPL.
7  */
8 
9 #include <linux/kernel.h>
10 #include <linux/cpuidle.h>
11 #include <linux/sysfs.h>
12 #include <linux/slab.h>
13 #include <linux/cpu.h>
14 
15 #include "cpuidle.h"
16 
17 static unsigned int sysfs_switch;
18 static int __init cpuidle_sysfs_setup(char *unused)
19 {
20 	sysfs_switch = 1;
21 	return 1;
22 }
23 __setup("cpuidle_sysfs_switch", cpuidle_sysfs_setup);
24 
25 static ssize_t show_available_governors(struct device *dev,
26 					struct device_attribute *attr,
27 					char *buf)
28 {
29 	ssize_t i = 0;
30 	struct cpuidle_governor *tmp;
31 
32 	mutex_lock(&cpuidle_lock);
33 	list_for_each_entry(tmp, &cpuidle_governors, governor_list) {
34 		if (i >= (ssize_t) ((PAGE_SIZE/sizeof(char)) - CPUIDLE_NAME_LEN - 2))
35 			goto out;
36 		i += scnprintf(&buf[i], CPUIDLE_NAME_LEN, "%s ", tmp->name);
37 	}
38 
39 out:
40 	i+= sprintf(&buf[i], "\n");
41 	mutex_unlock(&cpuidle_lock);
42 	return i;
43 }
44 
45 static ssize_t show_current_driver(struct device *dev,
46 				   struct device_attribute *attr,
47 				   char *buf)
48 {
49 	ssize_t ret;
50 	struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
51 
52 	spin_lock(&cpuidle_driver_lock);
53 	if (cpuidle_driver)
54 		ret = sprintf(buf, "%s\n", cpuidle_driver->name);
55 	else
56 		ret = sprintf(buf, "none\n");
57 	spin_unlock(&cpuidle_driver_lock);
58 
59 	return ret;
60 }
61 
62 static ssize_t show_current_governor(struct device *dev,
63 				     struct device_attribute *attr,
64 				     char *buf)
65 {
66 	ssize_t ret;
67 
68 	mutex_lock(&cpuidle_lock);
69 	if (cpuidle_curr_governor)
70 		ret = sprintf(buf, "%s\n", cpuidle_curr_governor->name);
71 	else
72 		ret = sprintf(buf, "none\n");
73 	mutex_unlock(&cpuidle_lock);
74 
75 	return ret;
76 }
77 
78 static ssize_t store_current_governor(struct device *dev,
79 				      struct device_attribute *attr,
80 				      const char *buf, size_t count)
81 {
82 	char gov_name[CPUIDLE_NAME_LEN];
83 	int ret = -EINVAL;
84 	size_t len = count;
85 	struct cpuidle_governor *gov;
86 
87 	if (!len || len >= sizeof(gov_name))
88 		return -EINVAL;
89 
90 	memcpy(gov_name, buf, len);
91 	gov_name[len] = '\0';
92 	if (gov_name[len - 1] == '\n')
93 		gov_name[--len] = '\0';
94 
95 	mutex_lock(&cpuidle_lock);
96 
97 	list_for_each_entry(gov, &cpuidle_governors, governor_list) {
98 		if (strlen(gov->name) == len && !strcmp(gov->name, gov_name)) {
99 			ret = cpuidle_switch_governor(gov);
100 			break;
101 		}
102 	}
103 
104 	mutex_unlock(&cpuidle_lock);
105 
106 	if (ret)
107 		return ret;
108 	else
109 		return count;
110 }
111 
112 static DEVICE_ATTR(current_driver, 0444, show_current_driver, NULL);
113 static DEVICE_ATTR(current_governor_ro, 0444, show_current_governor, NULL);
114 
115 static struct attribute *cpuidle_default_attrs[] = {
116 	&dev_attr_current_driver.attr,
117 	&dev_attr_current_governor_ro.attr,
118 	NULL
119 };
120 
121 static DEVICE_ATTR(available_governors, 0444, show_available_governors, NULL);
122 static DEVICE_ATTR(current_governor, 0644, show_current_governor,
123 		   store_current_governor);
124 
125 static struct attribute *cpuidle_switch_attrs[] = {
126 	&dev_attr_available_governors.attr,
127 	&dev_attr_current_driver.attr,
128 	&dev_attr_current_governor.attr,
129 	NULL
130 };
131 
132 static struct attribute_group cpuidle_attr_group = {
133 	.attrs = cpuidle_default_attrs,
134 	.name = "cpuidle",
135 };
136 
137 /**
138  * cpuidle_add_interface - add CPU global sysfs attributes
139  */
140 int cpuidle_add_interface(struct device *dev)
141 {
142 	if (sysfs_switch)
143 		cpuidle_attr_group.attrs = cpuidle_switch_attrs;
144 
145 	return sysfs_create_group(&dev->kobj, &cpuidle_attr_group);
146 }
147 
148 /**
149  * cpuidle_remove_interface - remove CPU global sysfs attributes
150  */
151 void cpuidle_remove_interface(struct device *dev)
152 {
153 	sysfs_remove_group(&dev->kobj, &cpuidle_attr_group);
154 }
155 
156 struct cpuidle_attr {
157 	struct attribute attr;
158 	ssize_t (*show)(struct cpuidle_device *, char *);
159 	ssize_t (*store)(struct cpuidle_device *, const char *, size_t count);
160 };
161 
162 #define define_one_ro(_name, show) \
163 	static struct cpuidle_attr attr_##_name = __ATTR(_name, 0444, show, NULL)
164 #define define_one_rw(_name, show, store) \
165 	static struct cpuidle_attr attr_##_name = __ATTR(_name, 0644, show, store)
166 
167 #define kobj_to_cpuidledev(k) container_of(k, struct cpuidle_device, kobj)
168 #define attr_to_cpuidleattr(a) container_of(a, struct cpuidle_attr, attr)
169 static ssize_t cpuidle_show(struct kobject * kobj, struct attribute * attr ,char * buf)
170 {
171 	int ret = -EIO;
172 	struct cpuidle_device *dev = kobj_to_cpuidledev(kobj);
173 	struct cpuidle_attr * cattr = attr_to_cpuidleattr(attr);
174 
175 	if (cattr->show) {
176 		mutex_lock(&cpuidle_lock);
177 		ret = cattr->show(dev, buf);
178 		mutex_unlock(&cpuidle_lock);
179 	}
180 	return ret;
181 }
182 
183 static ssize_t cpuidle_store(struct kobject * kobj, struct attribute * attr,
184 		     const char * buf, size_t count)
185 {
186 	int ret = -EIO;
187 	struct cpuidle_device *dev = kobj_to_cpuidledev(kobj);
188 	struct cpuidle_attr * cattr = attr_to_cpuidleattr(attr);
189 
190 	if (cattr->store) {
191 		mutex_lock(&cpuidle_lock);
192 		ret = cattr->store(dev, buf, count);
193 		mutex_unlock(&cpuidle_lock);
194 	}
195 	return ret;
196 }
197 
198 static const struct sysfs_ops cpuidle_sysfs_ops = {
199 	.show = cpuidle_show,
200 	.store = cpuidle_store,
201 };
202 
203 static void cpuidle_sysfs_release(struct kobject *kobj)
204 {
205 	struct cpuidle_device *dev = kobj_to_cpuidledev(kobj);
206 
207 	complete(&dev->kobj_unregister);
208 }
209 
210 static struct kobj_type ktype_cpuidle = {
211 	.sysfs_ops = &cpuidle_sysfs_ops,
212 	.release = cpuidle_sysfs_release,
213 };
214 
215 struct cpuidle_state_attr {
216 	struct attribute attr;
217 	ssize_t (*show)(struct cpuidle_state *, \
218 					struct cpuidle_state_usage *, char *);
219 	ssize_t (*store)(struct cpuidle_state *, const char *, size_t);
220 };
221 
222 #define define_one_state_ro(_name, show) \
223 static struct cpuidle_state_attr attr_##_name = __ATTR(_name, 0444, show, NULL)
224 
225 #define define_show_state_function(_name) \
226 static ssize_t show_state_##_name(struct cpuidle_state *state, \
227 			 struct cpuidle_state_usage *state_usage, char *buf) \
228 { \
229 	return sprintf(buf, "%u\n", state->_name);\
230 }
231 
232 #define define_show_state_ull_function(_name) \
233 static ssize_t show_state_##_name(struct cpuidle_state *state, \
234 			struct cpuidle_state_usage *state_usage, char *buf) \
235 { \
236 	return sprintf(buf, "%llu\n", state_usage->_name);\
237 }
238 
239 #define define_show_state_str_function(_name) \
240 static ssize_t show_state_##_name(struct cpuidle_state *state, \
241 			struct cpuidle_state_usage *state_usage, char *buf) \
242 { \
243 	if (state->_name[0] == '\0')\
244 		return sprintf(buf, "<null>\n");\
245 	return sprintf(buf, "%s\n", state->_name);\
246 }
247 
248 define_show_state_function(exit_latency)
249 define_show_state_function(power_usage)
250 define_show_state_ull_function(usage)
251 define_show_state_ull_function(time)
252 define_show_state_str_function(name)
253 define_show_state_str_function(desc)
254 
255 define_one_state_ro(name, show_state_name);
256 define_one_state_ro(desc, show_state_desc);
257 define_one_state_ro(latency, show_state_exit_latency);
258 define_one_state_ro(power, show_state_power_usage);
259 define_one_state_ro(usage, show_state_usage);
260 define_one_state_ro(time, show_state_time);
261 
262 static struct attribute *cpuidle_state_default_attrs[] = {
263 	&attr_name.attr,
264 	&attr_desc.attr,
265 	&attr_latency.attr,
266 	&attr_power.attr,
267 	&attr_usage.attr,
268 	&attr_time.attr,
269 	NULL
270 };
271 
272 #define kobj_to_state_obj(k) container_of(k, struct cpuidle_state_kobj, kobj)
273 #define kobj_to_state(k) (kobj_to_state_obj(k)->state)
274 #define kobj_to_state_usage(k) (kobj_to_state_obj(k)->state_usage)
275 #define attr_to_stateattr(a) container_of(a, struct cpuidle_state_attr, attr)
276 static ssize_t cpuidle_state_show(struct kobject * kobj,
277 	struct attribute * attr ,char * buf)
278 {
279 	int ret = -EIO;
280 	struct cpuidle_state *state = kobj_to_state(kobj);
281 	struct cpuidle_state_usage *state_usage = kobj_to_state_usage(kobj);
282 	struct cpuidle_state_attr * cattr = attr_to_stateattr(attr);
283 
284 	if (cattr->show)
285 		ret = cattr->show(state, state_usage, buf);
286 
287 	return ret;
288 }
289 
290 static const struct sysfs_ops cpuidle_state_sysfs_ops = {
291 	.show = cpuidle_state_show,
292 };
293 
294 static void cpuidle_state_sysfs_release(struct kobject *kobj)
295 {
296 	struct cpuidle_state_kobj *state_obj = kobj_to_state_obj(kobj);
297 
298 	complete(&state_obj->kobj_unregister);
299 }
300 
301 static struct kobj_type ktype_state_cpuidle = {
302 	.sysfs_ops = &cpuidle_state_sysfs_ops,
303 	.default_attrs = cpuidle_state_default_attrs,
304 	.release = cpuidle_state_sysfs_release,
305 };
306 
307 static inline void cpuidle_free_state_kobj(struct cpuidle_device *device, int i)
308 {
309 	kobject_put(&device->kobjs[i]->kobj);
310 	wait_for_completion(&device->kobjs[i]->kobj_unregister);
311 	kfree(device->kobjs[i]);
312 	device->kobjs[i] = NULL;
313 }
314 
315 /**
316  * cpuidle_add_driver_sysfs - adds driver-specific sysfs attributes
317  * @device: the target device
318  */
319 int cpuidle_add_state_sysfs(struct cpuidle_device *device)
320 {
321 	int i, ret = -ENOMEM;
322 	struct cpuidle_state_kobj *kobj;
323 	struct cpuidle_driver *drv = cpuidle_get_driver();
324 
325 	/* state statistics */
326 	for (i = 0; i < device->state_count; i++) {
327 		kobj = kzalloc(sizeof(struct cpuidle_state_kobj), GFP_KERNEL);
328 		if (!kobj)
329 			goto error_state;
330 		kobj->state = &drv->states[i];
331 		kobj->state_usage = &device->states_usage[i];
332 		init_completion(&kobj->kobj_unregister);
333 
334 		ret = kobject_init_and_add(&kobj->kobj, &ktype_state_cpuidle, &device->kobj,
335 					   "state%d", i);
336 		if (ret) {
337 			kfree(kobj);
338 			goto error_state;
339 		}
340 		kobject_uevent(&kobj->kobj, KOBJ_ADD);
341 		device->kobjs[i] = kobj;
342 	}
343 
344 	return 0;
345 
346 error_state:
347 	for (i = i - 1; i >= 0; i--)
348 		cpuidle_free_state_kobj(device, i);
349 	return ret;
350 }
351 
352 /**
353  * cpuidle_remove_driver_sysfs - removes driver-specific sysfs attributes
354  * @device: the target device
355  */
356 void cpuidle_remove_state_sysfs(struct cpuidle_device *device)
357 {
358 	int i;
359 
360 	for (i = 0; i < device->state_count; i++)
361 		cpuidle_free_state_kobj(device, i);
362 }
363 
364 /**
365  * cpuidle_add_sysfs - creates a sysfs instance for the target device
366  * @dev: the target device
367  */
368 int cpuidle_add_sysfs(struct device *cpu_dev)
369 {
370 	int cpu = cpu_dev->id;
371 	struct cpuidle_device *dev;
372 	int error;
373 
374 	dev = per_cpu(cpuidle_devices, cpu);
375 	error = kobject_init_and_add(&dev->kobj, &ktype_cpuidle, &cpu_dev->kobj,
376 				     "cpuidle");
377 	if (!error)
378 		kobject_uevent(&dev->kobj, KOBJ_ADD);
379 	return error;
380 }
381 
382 /**
383  * cpuidle_remove_sysfs - deletes a sysfs instance on the target device
384  * @dev: the target device
385  */
386 void cpuidle_remove_sysfs(struct device *cpu_dev)
387 {
388 	int cpu = cpu_dev->id;
389 	struct cpuidle_device *dev;
390 
391 	dev = per_cpu(cpuidle_devices, cpu);
392 	kobject_put(&dev->kobj);
393 }
394