Commit | Line | Data |
---|---|---|
d82b3518 MG |
1 | /* |
2 | * This module exposes the interface to kernel space for specifying | |
3 | * QoS dependencies. It provides infrastructure for registration of: | |
4 | * | |
ed77134b | 5 | * Dependents on a QoS value : register requests |
d82b3518 MG |
6 | * Watchers of QoS value : get notified when target QoS value changes |
7 | * | |
8 | * This QoS design is best effort based. Dependents register their QoS needs. | |
9 | * Watchers register to keep track of the current QoS needs of the system. | |
10 | * | |
11 | * There are 3 basic classes of QoS parameter: latency, timeout, throughput | |
12 | * each have defined units: | |
13 | * latency: usec | |
14 | * timeout: usec <-- currently not used. | |
15 | * throughput: kbs (kilo byte / sec) | |
16 | * | |
ed77134b | 17 | * There are lists of pm_qos_objects each one wrapping requests, notifiers |
d82b3518 | 18 | * |
ed77134b | 19 | * User mode requests on a QOS parameter register themselves to the |
d82b3518 MG |
20 | * subsystem by opening the device node /dev/... and writing there request to |
21 | * the node. As long as the process holds a file handle open to the node the | |
22 | * client continues to be accounted for. Upon file release the usermode | |
ed77134b MG |
23 | * request is removed and a new qos target is computed. This way when the |
24 | * request that the application has is cleaned up when closes the file | |
d82b3518 MG |
25 | * pointer or exits the pm_qos_object will get an opportunity to clean up. |
26 | * | |
bf1db69f | 27 | * Mark Gross <mgross@linux.intel.com> |
d82b3518 MG |
28 | */ |
29 | ||
ed77134b MG |
30 | /*#define DEBUG*/ |
31 | ||
e8db0be1 | 32 | #include <linux/pm_qos.h> |
d82b3518 MG |
33 | #include <linux/sched.h> |
34 | #include <linux/spinlock.h> | |
35 | #include <linux/slab.h> | |
36 | #include <linux/time.h> | |
37 | #include <linux/fs.h> | |
38 | #include <linux/device.h> | |
39 | #include <linux/miscdevice.h> | |
40 | #include <linux/string.h> | |
41 | #include <linux/platform_device.h> | |
42 | #include <linux/init.h> | |
0775a60a | 43 | #include <linux/kernel.h> |
d82b3518 MG |
44 | |
45 | #include <linux/uaccess.h> | |
6e5fdeed | 46 | #include <linux/export.h> |
d82b3518 MG |
47 | |
48 | /* | |
cc749986 | 49 | * locking rule: all changes to constraints or notifiers lists |
d82b3518 MG |
50 | * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock |
51 | * held, taken with _irqsave. One lock to rule them all | |
52 | */ | |
d82b3518 | 53 | struct pm_qos_object { |
4e1779ba | 54 | struct pm_qos_constraints *constraints; |
d82b3518 MG |
55 | struct miscdevice pm_qos_power_miscdev; |
56 | char *name; | |
d82b3518 MG |
57 | }; |
58 | ||
5f279845 JB |
59 | static DEFINE_SPINLOCK(pm_qos_lock); |
60 | ||
d82b3518 | 61 | static struct pm_qos_object null_pm_qos; |
4e1779ba | 62 | |
d82b3518 | 63 | static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier); |
4e1779ba JP |
64 | static struct pm_qos_constraints cpu_dma_constraints = { |
65 | .list = PLIST_HEAD_INIT(cpu_dma_constraints.list), | |
333c5ae9 TC |
66 | .target_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE, |
67 | .default_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE, | |
5f279845 | 68 | .type = PM_QOS_MIN, |
4e1779ba JP |
69 | .notifiers = &cpu_dma_lat_notifier, |
70 | }; | |
71 | static struct pm_qos_object cpu_dma_pm_qos = { | |
72 | .constraints = &cpu_dma_constraints, | |
a6f05b97 | 73 | .name = "cpu_dma_latency", |
d82b3518 MG |
74 | }; |
75 | ||
76 | static BLOCKING_NOTIFIER_HEAD(network_lat_notifier); | |
4e1779ba JP |
77 | static struct pm_qos_constraints network_lat_constraints = { |
78 | .list = PLIST_HEAD_INIT(network_lat_constraints.list), | |
333c5ae9 TC |
79 | .target_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE, |
80 | .default_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE, | |
4e1779ba JP |
81 | .type = PM_QOS_MIN, |
82 | .notifiers = &network_lat_notifier, | |
83 | }; | |
84 | static struct pm_qos_object network_lat_pm_qos = { | |
85 | .constraints = &network_lat_constraints, | |
86 | .name = "network_latency", | |
d82b3518 MG |
87 | }; |
88 | ||
89 | ||
90 | static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier); | |
4e1779ba JP |
91 | static struct pm_qos_constraints network_tput_constraints = { |
92 | .list = PLIST_HEAD_INIT(network_tput_constraints.list), | |
333c5ae9 TC |
93 | .target_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE, |
94 | .default_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE, | |
5f279845 | 95 | .type = PM_QOS_MAX, |
4e1779ba JP |
96 | .notifiers = &network_throughput_notifier, |
97 | }; | |
98 | static struct pm_qos_object network_throughput_pm_qos = { | |
99 | .constraints = &network_tput_constraints, | |
100 | .name = "network_throughput", | |
d82b3518 MG |
101 | }; |
102 | ||
103 | ||
104 | static struct pm_qos_object *pm_qos_array[] = { | |
105 | &null_pm_qos, | |
106 | &cpu_dma_pm_qos, | |
107 | &network_lat_pm_qos, | |
108 | &network_throughput_pm_qos | |
109 | }; | |
110 | ||
d82b3518 MG |
111 | static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf, |
112 | size_t count, loff_t *f_pos); | |
f9b9e806 TR |
113 | static ssize_t pm_qos_power_read(struct file *filp, char __user *buf, |
114 | size_t count, loff_t *f_pos); | |
d82b3518 MG |
115 | static int pm_qos_power_open(struct inode *inode, struct file *filp); |
116 | static int pm_qos_power_release(struct inode *inode, struct file *filp); | |
117 | ||
118 | static const struct file_operations pm_qos_power_fops = { | |
119 | .write = pm_qos_power_write, | |
f9b9e806 | 120 | .read = pm_qos_power_read, |
d82b3518 MG |
121 | .open = pm_qos_power_open, |
122 | .release = pm_qos_power_release, | |
6038f373 | 123 | .llseek = noop_llseek, |
d82b3518 MG |
124 | }; |
125 | ||
5f279845 | 126 | /* unlocked internal variant */ |
abe98ec2 | 127 | static inline int pm_qos_get_value(struct pm_qos_constraints *c) |
d82b3518 | 128 | { |
abe98ec2 JP |
129 | if (plist_head_empty(&c->list)) |
130 | return c->default_value; | |
d82b3518 | 131 | |
abe98ec2 | 132 | switch (c->type) { |
5f279845 | 133 | case PM_QOS_MIN: |
abe98ec2 | 134 | return plist_first(&c->list)->prio; |
d82b3518 | 135 | |
5f279845 | 136 | case PM_QOS_MAX: |
abe98ec2 | 137 | return plist_last(&c->list)->prio; |
d82b3518 | 138 | |
5f279845 JB |
139 | default: |
140 | /* runtime check for not using enum */ | |
141 | BUG(); | |
142 | } | |
143 | } | |
144 | ||
b66213cd | 145 | s32 pm_qos_read_value(struct pm_qos_constraints *c) |
333c5ae9 | 146 | { |
abe98ec2 | 147 | return c->target_value; |
333c5ae9 TC |
148 | } |
149 | ||
abe98ec2 | 150 | static inline void pm_qos_set_value(struct pm_qos_constraints *c, s32 value) |
333c5ae9 | 151 | { |
abe98ec2 | 152 | c->target_value = value; |
333c5ae9 TC |
153 | } |
154 | ||
abe98ec2 JP |
155 | /** |
156 | * pm_qos_update_target - manages the constraints list and calls the notifiers | |
157 | * if needed | |
158 | * @c: constraints data struct | |
159 | * @node: request to add to the list, to update or to remove | |
160 | * @action: action to take on the constraints list | |
161 | * @value: value of the request to add or update | |
162 | * | |
163 | * This function returns 1 if the aggregated constraint value has changed, 0 | |
164 | * otherwise. | |
165 | */ | |
166 | int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node, | |
167 | enum pm_qos_req_action action, int value) | |
d82b3518 | 168 | { |
d82b3518 | 169 | unsigned long flags; |
abe98ec2 | 170 | int prev_value, curr_value, new_value; |
d82b3518 MG |
171 | |
172 | spin_lock_irqsave(&pm_qos_lock, flags); | |
abe98ec2 JP |
173 | prev_value = pm_qos_get_value(c); |
174 | if (value == PM_QOS_DEFAULT_VALUE) | |
175 | new_value = c->default_value; | |
176 | else | |
177 | new_value = value; | |
178 | ||
179 | switch (action) { | |
180 | case PM_QOS_REMOVE_REQ: | |
181 | plist_del(node, &c->list); | |
182 | break; | |
183 | case PM_QOS_UPDATE_REQ: | |
5f279845 JB |
184 | /* |
185 | * to change the list, we atomically remove, reinit | |
186 | * with new value and add, then see if the extremal | |
187 | * changed | |
188 | */ | |
abe98ec2 JP |
189 | plist_del(node, &c->list); |
190 | case PM_QOS_ADD_REQ: | |
191 | plist_node_init(node, new_value); | |
192 | plist_add(node, &c->list); | |
193 | break; | |
194 | default: | |
195 | /* no action */ | |
196 | ; | |
d82b3518 | 197 | } |
abe98ec2 JP |
198 | |
199 | curr_value = pm_qos_get_value(c); | |
200 | pm_qos_set_value(c, curr_value); | |
201 | ||
d82b3518 MG |
202 | spin_unlock_irqrestore(&pm_qos_lock, flags); |
203 | ||
abe98ec2 JP |
204 | if (prev_value != curr_value) { |
205 | blocking_notifier_call_chain(c->notifiers, | |
5f279845 JB |
206 | (unsigned long)curr_value, |
207 | NULL); | |
abe98ec2 JP |
208 | return 1; |
209 | } else { | |
210 | return 0; | |
211 | } | |
d82b3518 MG |
212 | } |
213 | ||
d82b3518 | 214 | /** |
ed77134b | 215 | * pm_qos_request - returns current system wide qos expectation |
d82b3518 MG |
216 | * @pm_qos_class: identification of which qos value is requested |
217 | * | |
333c5ae9 | 218 | * This function returns the current target value. |
d82b3518 | 219 | */ |
ed77134b | 220 | int pm_qos_request(int pm_qos_class) |
d82b3518 | 221 | { |
abe98ec2 | 222 | return pm_qos_read_value(pm_qos_array[pm_qos_class]->constraints); |
d82b3518 | 223 | } |
ed77134b | 224 | EXPORT_SYMBOL_GPL(pm_qos_request); |
d82b3518 | 225 | |
cc749986 | 226 | int pm_qos_request_active(struct pm_qos_request *req) |
82f68251 JB |
227 | { |
228 | return req->pm_qos_class != 0; | |
229 | } | |
230 | EXPORT_SYMBOL_GPL(pm_qos_request_active); | |
231 | ||
d82b3518 | 232 | /** |
ed77134b | 233 | * pm_qos_add_request - inserts new qos request into the list |
cc749986 | 234 | * @req: pointer to a preallocated handle |
25cc69ec | 235 | * @pm_qos_class: identifies which list of qos request to use |
d82b3518 MG |
236 | * @value: defines the qos request |
237 | * | |
238 | * This function inserts a new entry in the pm_qos_class list of requested qos | |
bf1db69f | 239 | * performance characteristics. It recomputes the aggregate QoS expectations |
cc749986 | 240 | * for the pm_qos_class of parameters and initializes the pm_qos_request |
25cc69ec SK |
241 | * handle. Caller needs to save this handle for later use in updates and |
242 | * removal. | |
d82b3518 | 243 | */ |
25cc69ec | 244 | |
cc749986 | 245 | void pm_qos_add_request(struct pm_qos_request *req, |
82f68251 | 246 | int pm_qos_class, s32 value) |
d82b3518 | 247 | { |
abe98ec2 JP |
248 | if (!req) /*guard against callers passing in null */ |
249 | return; | |
d82b3518 | 250 | |
cc749986 | 251 | if (pm_qos_request_active(req)) { |
82f68251 JB |
252 | WARN(1, KERN_ERR "pm_qos_add_request() called for already added request\n"); |
253 | return; | |
254 | } | |
cc749986 | 255 | req->pm_qos_class = pm_qos_class; |
abe98ec2 JP |
256 | pm_qos_update_target(pm_qos_array[pm_qos_class]->constraints, |
257 | &req->node, PM_QOS_ADD_REQ, value); | |
d82b3518 | 258 | } |
ed77134b | 259 | EXPORT_SYMBOL_GPL(pm_qos_add_request); |
d82b3518 MG |
260 | |
261 | /** | |
ed77134b | 262 | * pm_qos_update_request - modifies an existing qos request |
cc749986 | 263 | * @req : handle to list element holding a pm_qos request to use |
d82b3518 MG |
264 | * @value: defines the qos request |
265 | * | |
ed77134b | 266 | * Updates an existing qos request for the pm_qos_class of parameters along |
d82b3518 MG |
267 | * with updating the target pm_qos_class value. |
268 | * | |
ed77134b | 269 | * Attempts are made to make this code callable on hot code paths. |
d82b3518 | 270 | */ |
cc749986 | 271 | void pm_qos_update_request(struct pm_qos_request *req, |
5f279845 | 272 | s32 new_value) |
d82b3518 | 273 | { |
cc749986 | 274 | if (!req) /*guard against callers passing in null */ |
5f279845 JB |
275 | return; |
276 | ||
cc749986 | 277 | if (!pm_qos_request_active(req)) { |
82f68251 JB |
278 | WARN(1, KERN_ERR "pm_qos_update_request() called for unknown object\n"); |
279 | return; | |
280 | } | |
281 | ||
abe98ec2 JP |
282 | if (new_value != req->node.prio) |
283 | pm_qos_update_target( | |
284 | pm_qos_array[req->pm_qos_class]->constraints, | |
285 | &req->node, PM_QOS_UPDATE_REQ, new_value); | |
d82b3518 | 286 | } |
ed77134b | 287 | EXPORT_SYMBOL_GPL(pm_qos_update_request); |
d82b3518 MG |
288 | |
289 | /** | |
ed77134b | 290 | * pm_qos_remove_request - modifies an existing qos request |
cc749986 | 291 | * @req: handle to request list element |
d82b3518 | 292 | * |
cc749986 | 293 | * Will remove pm qos request from the list of constraints and |
ed77134b MG |
294 | * recompute the current target value for the pm_qos_class. Call this |
295 | * on slow code paths. | |
d82b3518 | 296 | */ |
cc749986 | 297 | void pm_qos_remove_request(struct pm_qos_request *req) |
d82b3518 | 298 | { |
abe98ec2 | 299 | if (!req) /*guard against callers passing in null */ |
ed77134b MG |
300 | return; |
301 | /* silent return to keep pcm code cleaner */ | |
d82b3518 | 302 | |
cc749986 | 303 | if (!pm_qos_request_active(req)) { |
82f68251 JB |
304 | WARN(1, KERN_ERR "pm_qos_remove_request() called for unknown object\n"); |
305 | return; | |
306 | } | |
307 | ||
abe98ec2 JP |
308 | pm_qos_update_target(pm_qos_array[req->pm_qos_class]->constraints, |
309 | &req->node, PM_QOS_REMOVE_REQ, | |
310 | PM_QOS_DEFAULT_VALUE); | |
cc749986 | 311 | memset(req, 0, sizeof(*req)); |
d82b3518 | 312 | } |
ed77134b | 313 | EXPORT_SYMBOL_GPL(pm_qos_remove_request); |
d82b3518 MG |
314 | |
315 | /** | |
316 | * pm_qos_add_notifier - sets notification entry for changes to target value | |
317 | * @pm_qos_class: identifies which qos target changes should be notified. | |
318 | * @notifier: notifier block managed by caller. | |
319 | * | |
320 | * will register the notifier into a notification chain that gets called | |
bf1db69f | 321 | * upon changes to the pm_qos_class target value. |
d82b3518 | 322 | */ |
ed77134b | 323 | int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier) |
d82b3518 MG |
324 | { |
325 | int retval; | |
326 | ||
327 | retval = blocking_notifier_chain_register( | |
4e1779ba JP |
328 | pm_qos_array[pm_qos_class]->constraints->notifiers, |
329 | notifier); | |
d82b3518 MG |
330 | |
331 | return retval; | |
332 | } | |
333 | EXPORT_SYMBOL_GPL(pm_qos_add_notifier); | |
334 | ||
335 | /** | |
336 | * pm_qos_remove_notifier - deletes notification entry from chain. | |
337 | * @pm_qos_class: identifies which qos target changes are notified. | |
338 | * @notifier: notifier block to be removed. | |
339 | * | |
340 | * will remove the notifier from the notification chain that gets called | |
bf1db69f | 341 | * upon changes to the pm_qos_class target value. |
d82b3518 MG |
342 | */ |
343 | int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier) | |
344 | { | |
345 | int retval; | |
346 | ||
347 | retval = blocking_notifier_chain_unregister( | |
4e1779ba JP |
348 | pm_qos_array[pm_qos_class]->constraints->notifiers, |
349 | notifier); | |
d82b3518 MG |
350 | |
351 | return retval; | |
352 | } | |
353 | EXPORT_SYMBOL_GPL(pm_qos_remove_notifier); | |
354 | ||
4a31a334 JP |
355 | /* User space interface to PM QoS classes via misc devices */ |
356 | static int register_pm_qos_misc(struct pm_qos_object *qos) | |
357 | { | |
358 | qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR; | |
359 | qos->pm_qos_power_miscdev.name = qos->name; | |
360 | qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops; | |
361 | ||
362 | return misc_register(&qos->pm_qos_power_miscdev); | |
363 | } | |
364 | ||
365 | static int find_pm_qos_object_by_minor(int minor) | |
366 | { | |
367 | int pm_qos_class; | |
368 | ||
369 | for (pm_qos_class = 0; | |
370 | pm_qos_class < PM_QOS_NUM_CLASSES; pm_qos_class++) { | |
371 | if (minor == | |
372 | pm_qos_array[pm_qos_class]->pm_qos_power_miscdev.minor) | |
373 | return pm_qos_class; | |
374 | } | |
375 | return -1; | |
376 | } | |
377 | ||
d82b3518 MG |
378 | static int pm_qos_power_open(struct inode *inode, struct file *filp) |
379 | { | |
d82b3518 MG |
380 | long pm_qos_class; |
381 | ||
382 | pm_qos_class = find_pm_qos_object_by_minor(iminor(inode)); | |
383 | if (pm_qos_class >= 0) { | |
cc749986 | 384 | struct pm_qos_request *req = kzalloc(sizeof(*req), GFP_KERNEL); |
82f68251 JB |
385 | if (!req) |
386 | return -ENOMEM; | |
387 | ||
388 | pm_qos_add_request(req, pm_qos_class, PM_QOS_DEFAULT_VALUE); | |
389 | filp->private_data = req; | |
ed77134b | 390 | |
6513fd69 | 391 | return 0; |
d82b3518 | 392 | } |
d82b3518 MG |
393 | return -EPERM; |
394 | } | |
395 | ||
396 | static int pm_qos_power_release(struct inode *inode, struct file *filp) | |
397 | { | |
cc749986 | 398 | struct pm_qos_request *req; |
d82b3518 | 399 | |
82f68251 | 400 | req = filp->private_data; |
ed77134b | 401 | pm_qos_remove_request(req); |
82f68251 | 402 | kfree(req); |
d82b3518 MG |
403 | |
404 | return 0; | |
405 | } | |
406 | ||
ed77134b | 407 | |
f9b9e806 TR |
408 | static ssize_t pm_qos_power_read(struct file *filp, char __user *buf, |
409 | size_t count, loff_t *f_pos) | |
410 | { | |
411 | s32 value; | |
412 | unsigned long flags; | |
cc749986 | 413 | struct pm_qos_request *req = filp->private_data; |
f9b9e806 | 414 | |
cc749986 | 415 | if (!req) |
f9b9e806 | 416 | return -EINVAL; |
cc749986 | 417 | if (!pm_qos_request_active(req)) |
f9b9e806 TR |
418 | return -EINVAL; |
419 | ||
f9b9e806 | 420 | spin_lock_irqsave(&pm_qos_lock, flags); |
abe98ec2 | 421 | value = pm_qos_get_value(pm_qos_array[req->pm_qos_class]->constraints); |
f9b9e806 TR |
422 | spin_unlock_irqrestore(&pm_qos_lock, flags); |
423 | ||
424 | return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32)); | |
425 | } | |
426 | ||
d82b3518 MG |
427 | static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf, |
428 | size_t count, loff_t *f_pos) | |
429 | { | |
430 | s32 value; | |
cc749986 | 431 | struct pm_qos_request *req; |
ed77134b MG |
432 | |
433 | if (count == sizeof(s32)) { | |
434 | if (copy_from_user(&value, buf, sizeof(s32))) | |
435 | return -EFAULT; | |
0775a60a RW |
436 | } else if (count <= 11) { /* ASCII perhaps? */ |
437 | char ascii_value[11]; | |
438 | unsigned long int ulval; | |
439 | int ret; | |
440 | ||
441 | if (copy_from_user(ascii_value, buf, count)) | |
ed77134b | 442 | return -EFAULT; |
0775a60a RW |
443 | |
444 | if (count > 10) { | |
445 | if (ascii_value[10] == '\n') | |
446 | ascii_value[10] = '\0'; | |
447 | else | |
448 | return -EINVAL; | |
449 | } else { | |
450 | ascii_value[count] = '\0'; | |
451 | } | |
452 | ret = strict_strtoul(ascii_value, 16, &ulval); | |
453 | if (ret) { | |
454 | pr_debug("%s, 0x%lx, 0x%x\n", ascii_value, ulval, ret); | |
ed77134b | 455 | return -EINVAL; |
0775a60a RW |
456 | } |
457 | value = (s32)lower_32_bits(ulval); | |
458 | } else { | |
d82b3518 | 459 | return -EINVAL; |
0775a60a | 460 | } |
d82b3518 | 461 | |
cc749986 JP |
462 | req = filp->private_data; |
463 | pm_qos_update_request(req, value); | |
ed77134b MG |
464 | |
465 | return count; | |
d82b3518 MG |
466 | } |
467 | ||
468 | ||
469 | static int __init pm_qos_power_init(void) | |
470 | { | |
471 | int ret = 0; | |
472 | ||
473 | ret = register_pm_qos_misc(&cpu_dma_pm_qos); | |
474 | if (ret < 0) { | |
475 | printk(KERN_ERR "pm_qos_param: cpu_dma_latency setup failed\n"); | |
476 | return ret; | |
477 | } | |
478 | ret = register_pm_qos_misc(&network_lat_pm_qos); | |
479 | if (ret < 0) { | |
480 | printk(KERN_ERR "pm_qos_param: network_latency setup failed\n"); | |
481 | return ret; | |
482 | } | |
483 | ret = register_pm_qos_misc(&network_throughput_pm_qos); | |
484 | if (ret < 0) | |
485 | printk(KERN_ERR | |
486 | "pm_qos_param: network_throughput setup failed\n"); | |
487 | ||
488 | return ret; | |
489 | } | |
490 | ||
491 | late_initcall(pm_qos_power_init); |