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