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 | ||
d82b3518 MG |
32 | #include <linux/pm_qos_params.h> |
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 | /* | |
ed77134b | 48 | * locking rule: all changes to requests 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 | */ | |
5f279845 JB |
52 | enum pm_qos_type { |
53 | PM_QOS_MAX, /* return the largest value */ | |
54 | PM_QOS_MIN /* return the smallest value */ | |
55 | }; | |
d82b3518 | 56 | |
333c5ae9 TC |
57 | /* |
58 | * Note: The lockless read path depends on the CPU accessing | |
59 | * target_value atomically. Atomic access is only guaranteed on all CPU | |
60 | * types linux supports for 32 bit quantites | |
61 | */ | |
d82b3518 | 62 | struct pm_qos_object { |
5f279845 | 63 | struct plist_head requests; |
d82b3518 MG |
64 | struct blocking_notifier_head *notifiers; |
65 | struct miscdevice pm_qos_power_miscdev; | |
66 | char *name; | |
333c5ae9 | 67 | s32 target_value; /* Do not change to 64 bit */ |
d82b3518 | 68 | s32 default_value; |
5f279845 | 69 | enum pm_qos_type type; |
d82b3518 MG |
70 | }; |
71 | ||
5f279845 JB |
72 | static DEFINE_SPINLOCK(pm_qos_lock); |
73 | ||
d82b3518 MG |
74 | static struct pm_qos_object null_pm_qos; |
75 | static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier); | |
76 | static struct pm_qos_object cpu_dma_pm_qos = { | |
5f279845 | 77 | .requests = PLIST_HEAD_INIT(cpu_dma_pm_qos.requests, pm_qos_lock), |
d82b3518 MG |
78 | .notifiers = &cpu_dma_lat_notifier, |
79 | .name = "cpu_dma_latency", | |
333c5ae9 TC |
80 | .target_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE, |
81 | .default_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE, | |
5f279845 | 82 | .type = PM_QOS_MIN, |
d82b3518 MG |
83 | }; |
84 | ||
85 | static BLOCKING_NOTIFIER_HEAD(network_lat_notifier); | |
86 | static struct pm_qos_object network_lat_pm_qos = { | |
5f279845 | 87 | .requests = PLIST_HEAD_INIT(network_lat_pm_qos.requests, pm_qos_lock), |
d82b3518 MG |
88 | .notifiers = &network_lat_notifier, |
89 | .name = "network_latency", | |
333c5ae9 TC |
90 | .target_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE, |
91 | .default_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE, | |
5f279845 | 92 | .type = PM_QOS_MIN |
d82b3518 MG |
93 | }; |
94 | ||
95 | ||
96 | static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier); | |
97 | static struct pm_qos_object network_throughput_pm_qos = { | |
5f279845 | 98 | .requests = PLIST_HEAD_INIT(network_throughput_pm_qos.requests, pm_qos_lock), |
d82b3518 MG |
99 | .notifiers = &network_throughput_notifier, |
100 | .name = "network_throughput", | |
333c5ae9 TC |
101 | .target_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE, |
102 | .default_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE, | |
5f279845 | 103 | .type = PM_QOS_MAX, |
d82b3518 MG |
104 | }; |
105 | ||
106 | ||
107 | static struct pm_qos_object *pm_qos_array[] = { | |
108 | &null_pm_qos, | |
109 | &cpu_dma_pm_qos, | |
110 | &network_lat_pm_qos, | |
111 | &network_throughput_pm_qos | |
112 | }; | |
113 | ||
d82b3518 MG |
114 | static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf, |
115 | size_t count, loff_t *f_pos); | |
f9b9e806 TR |
116 | static ssize_t pm_qos_power_read(struct file *filp, char __user *buf, |
117 | size_t count, loff_t *f_pos); | |
d82b3518 MG |
118 | static int pm_qos_power_open(struct inode *inode, struct file *filp); |
119 | static int pm_qos_power_release(struct inode *inode, struct file *filp); | |
120 | ||
121 | static const struct file_operations pm_qos_power_fops = { | |
122 | .write = pm_qos_power_write, | |
f9b9e806 | 123 | .read = pm_qos_power_read, |
d82b3518 MG |
124 | .open = pm_qos_power_open, |
125 | .release = pm_qos_power_release, | |
6038f373 | 126 | .llseek = noop_llseek, |
d82b3518 MG |
127 | }; |
128 | ||
5f279845 JB |
129 | /* unlocked internal variant */ |
130 | static inline int pm_qos_get_value(struct pm_qos_object *o) | |
d82b3518 | 131 | { |
5f279845 JB |
132 | if (plist_head_empty(&o->requests)) |
133 | return o->default_value; | |
d82b3518 | 134 | |
5f279845 JB |
135 | switch (o->type) { |
136 | case PM_QOS_MIN: | |
00fafcda | 137 | return plist_first(&o->requests)->prio; |
d82b3518 | 138 | |
5f279845 | 139 | case PM_QOS_MAX: |
00fafcda | 140 | return plist_last(&o->requests)->prio; |
d82b3518 | 141 | |
5f279845 JB |
142 | default: |
143 | /* runtime check for not using enum */ | |
144 | BUG(); | |
145 | } | |
146 | } | |
147 | ||
333c5ae9 TC |
148 | static inline s32 pm_qos_read_value(struct pm_qos_object *o) |
149 | { | |
150 | return o->target_value; | |
151 | } | |
152 | ||
153 | static inline void pm_qos_set_value(struct pm_qos_object *o, s32 value) | |
154 | { | |
155 | o->target_value = value; | |
156 | } | |
157 | ||
5f279845 JB |
158 | static void update_target(struct pm_qos_object *o, struct plist_node *node, |
159 | int del, int value) | |
d82b3518 | 160 | { |
d82b3518 | 161 | unsigned long flags; |
5f279845 | 162 | int prev_value, curr_value; |
d82b3518 MG |
163 | |
164 | spin_lock_irqsave(&pm_qos_lock, flags); | |
5f279845 JB |
165 | prev_value = pm_qos_get_value(o); |
166 | /* PM_QOS_DEFAULT_VALUE is a signal that the value is unchanged */ | |
167 | if (value != PM_QOS_DEFAULT_VALUE) { | |
168 | /* | |
169 | * to change the list, we atomically remove, reinit | |
170 | * with new value and add, then see if the extremal | |
171 | * changed | |
172 | */ | |
173 | plist_del(node, &o->requests); | |
174 | plist_node_init(node, value); | |
175 | plist_add(node, &o->requests); | |
176 | } else if (del) { | |
177 | plist_del(node, &o->requests); | |
178 | } else { | |
179 | plist_add(node, &o->requests); | |
d82b3518 | 180 | } |
5f279845 | 181 | curr_value = pm_qos_get_value(o); |
333c5ae9 | 182 | pm_qos_set_value(o, curr_value); |
d82b3518 MG |
183 | spin_unlock_irqrestore(&pm_qos_lock, flags); |
184 | ||
5f279845 JB |
185 | if (prev_value != curr_value) |
186 | blocking_notifier_call_chain(o->notifiers, | |
187 | (unsigned long)curr_value, | |
188 | NULL); | |
d82b3518 MG |
189 | } |
190 | ||
191 | static int register_pm_qos_misc(struct pm_qos_object *qos) | |
192 | { | |
193 | qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR; | |
194 | qos->pm_qos_power_miscdev.name = qos->name; | |
195 | qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops; | |
196 | ||
197 | return misc_register(&qos->pm_qos_power_miscdev); | |
198 | } | |
199 | ||
200 | static int find_pm_qos_object_by_minor(int minor) | |
201 | { | |
202 | int pm_qos_class; | |
203 | ||
204 | for (pm_qos_class = 0; | |
205 | pm_qos_class < PM_QOS_NUM_CLASSES; pm_qos_class++) { | |
206 | if (minor == | |
207 | pm_qos_array[pm_qos_class]->pm_qos_power_miscdev.minor) | |
208 | return pm_qos_class; | |
209 | } | |
210 | return -1; | |
211 | } | |
212 | ||
213 | /** | |
ed77134b | 214 | * pm_qos_request - returns current system wide qos expectation |
d82b3518 MG |
215 | * @pm_qos_class: identification of which qos value is requested |
216 | * | |
333c5ae9 | 217 | * This function returns the current target value. |
d82b3518 | 218 | */ |
ed77134b | 219 | int pm_qos_request(int pm_qos_class) |
d82b3518 | 220 | { |
333c5ae9 | 221 | return pm_qos_read_value(pm_qos_array[pm_qos_class]); |
d82b3518 | 222 | } |
ed77134b | 223 | EXPORT_SYMBOL_GPL(pm_qos_request); |
d82b3518 | 224 | |
82f68251 JB |
225 | int pm_qos_request_active(struct pm_qos_request_list *req) |
226 | { | |
227 | return req->pm_qos_class != 0; | |
228 | } | |
229 | EXPORT_SYMBOL_GPL(pm_qos_request_active); | |
230 | ||
d82b3518 | 231 | /** |
ed77134b | 232 | * pm_qos_add_request - inserts new qos request into the list |
25cc69ec SK |
233 | * @dep: pointer to a preallocated handle |
234 | * @pm_qos_class: identifies which list of qos request to use | |
d82b3518 MG |
235 | * @value: defines the qos request |
236 | * | |
237 | * This function inserts a new entry in the pm_qos_class list of requested qos | |
bf1db69f | 238 | * performance characteristics. It recomputes the aggregate QoS expectations |
25cc69ec SK |
239 | * for the pm_qos_class of parameters and initializes the pm_qos_request_list |
240 | * handle. Caller needs to save this handle for later use in updates and | |
241 | * removal. | |
d82b3518 | 242 | */ |
25cc69ec | 243 | |
82f68251 JB |
244 | void pm_qos_add_request(struct pm_qos_request_list *dep, |
245 | int pm_qos_class, s32 value) | |
d82b3518 | 246 | { |
82f68251 JB |
247 | struct pm_qos_object *o = pm_qos_array[pm_qos_class]; |
248 | int new_value; | |
d82b3518 | 249 | |
82f68251 JB |
250 | if (pm_qos_request_active(dep)) { |
251 | WARN(1, KERN_ERR "pm_qos_add_request() called for already added request\n"); | |
252 | return; | |
253 | } | |
254 | if (value == PM_QOS_DEFAULT_VALUE) | |
255 | new_value = o->default_value; | |
256 | else | |
257 | new_value = value; | |
258 | plist_node_init(&dep->list, new_value); | |
259 | dep->pm_qos_class = pm_qos_class; | |
260 | update_target(o, &dep->list, 0, PM_QOS_DEFAULT_VALUE); | |
d82b3518 | 261 | } |
ed77134b | 262 | EXPORT_SYMBOL_GPL(pm_qos_add_request); |
d82b3518 MG |
263 | |
264 | /** | |
ed77134b MG |
265 | * pm_qos_update_request - modifies an existing qos request |
266 | * @pm_qos_req : handle to list element holding a pm_qos request to use | |
d82b3518 MG |
267 | * @value: defines the qos request |
268 | * | |
ed77134b | 269 | * Updates an existing qos request for the pm_qos_class of parameters along |
d82b3518 MG |
270 | * with updating the target pm_qos_class value. |
271 | * | |
ed77134b | 272 | * Attempts are made to make this code callable on hot code paths. |
d82b3518 | 273 | */ |
ed77134b | 274 | void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req, |
5f279845 | 275 | s32 new_value) |
d82b3518 | 276 | { |
ed77134b | 277 | s32 temp; |
5f279845 | 278 | struct pm_qos_object *o; |
d82b3518 | 279 | |
5f279845 JB |
280 | if (!pm_qos_req) /*guard against callers passing in null */ |
281 | return; | |
282 | ||
82f68251 JB |
283 | if (!pm_qos_request_active(pm_qos_req)) { |
284 | WARN(1, KERN_ERR "pm_qos_update_request() called for unknown object\n"); | |
285 | return; | |
286 | } | |
287 | ||
5f279845 JB |
288 | o = pm_qos_array[pm_qos_req->pm_qos_class]; |
289 | ||
290 | if (new_value == PM_QOS_DEFAULT_VALUE) | |
291 | temp = o->default_value; | |
292 | else | |
293 | temp = new_value; | |
294 | ||
295 | if (temp != pm_qos_req->list.prio) | |
296 | update_target(o, &pm_qos_req->list, 0, temp); | |
d82b3518 | 297 | } |
ed77134b | 298 | EXPORT_SYMBOL_GPL(pm_qos_update_request); |
d82b3518 MG |
299 | |
300 | /** | |
ed77134b MG |
301 | * pm_qos_remove_request - modifies an existing qos request |
302 | * @pm_qos_req: handle to request list element | |
d82b3518 | 303 | * |
ed77134b MG |
304 | * Will remove pm qos request from the list of requests and |
305 | * recompute the current target value for the pm_qos_class. Call this | |
306 | * on slow code paths. | |
d82b3518 | 307 | */ |
ed77134b | 308 | void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req) |
d82b3518 | 309 | { |
5f279845 | 310 | struct pm_qos_object *o; |
ed77134b MG |
311 | |
312 | if (pm_qos_req == NULL) | |
313 | return; | |
314 | /* silent return to keep pcm code cleaner */ | |
d82b3518 | 315 | |
82f68251 JB |
316 | if (!pm_qos_request_active(pm_qos_req)) { |
317 | WARN(1, KERN_ERR "pm_qos_remove_request() called for unknown object\n"); | |
318 | return; | |
319 | } | |
320 | ||
5f279845 JB |
321 | o = pm_qos_array[pm_qos_req->pm_qos_class]; |
322 | update_target(o, &pm_qos_req->list, 1, PM_QOS_DEFAULT_VALUE); | |
82f68251 | 323 | memset(pm_qos_req, 0, sizeof(*pm_qos_req)); |
d82b3518 | 324 | } |
ed77134b | 325 | EXPORT_SYMBOL_GPL(pm_qos_remove_request); |
d82b3518 MG |
326 | |
327 | /** | |
328 | * pm_qos_add_notifier - sets notification entry for changes to target value | |
329 | * @pm_qos_class: identifies which qos target changes should be notified. | |
330 | * @notifier: notifier block managed by caller. | |
331 | * | |
332 | * will register the notifier into a notification chain that gets called | |
bf1db69f | 333 | * upon changes to the pm_qos_class target value. |
d82b3518 | 334 | */ |
ed77134b | 335 | int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier) |
d82b3518 MG |
336 | { |
337 | int retval; | |
338 | ||
339 | retval = blocking_notifier_chain_register( | |
340 | pm_qos_array[pm_qos_class]->notifiers, notifier); | |
341 | ||
342 | return retval; | |
343 | } | |
344 | EXPORT_SYMBOL_GPL(pm_qos_add_notifier); | |
345 | ||
346 | /** | |
347 | * pm_qos_remove_notifier - deletes notification entry from chain. | |
348 | * @pm_qos_class: identifies which qos target changes are notified. | |
349 | * @notifier: notifier block to be removed. | |
350 | * | |
351 | * will remove the notifier from the notification chain that gets called | |
bf1db69f | 352 | * upon changes to the pm_qos_class target value. |
d82b3518 MG |
353 | */ |
354 | int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier) | |
355 | { | |
356 | int retval; | |
357 | ||
358 | retval = blocking_notifier_chain_unregister( | |
359 | pm_qos_array[pm_qos_class]->notifiers, notifier); | |
360 | ||
361 | return retval; | |
362 | } | |
363 | EXPORT_SYMBOL_GPL(pm_qos_remove_notifier); | |
364 | ||
d82b3518 MG |
365 | static int pm_qos_power_open(struct inode *inode, struct file *filp) |
366 | { | |
d82b3518 MG |
367 | long pm_qos_class; |
368 | ||
369 | pm_qos_class = find_pm_qos_object_by_minor(iminor(inode)); | |
370 | if (pm_qos_class >= 0) { | |
bac1e74d | 371 | struct pm_qos_request_list *req = kzalloc(sizeof(*req), GFP_KERNEL); |
82f68251 JB |
372 | if (!req) |
373 | return -ENOMEM; | |
374 | ||
375 | pm_qos_add_request(req, pm_qos_class, PM_QOS_DEFAULT_VALUE); | |
376 | filp->private_data = req; | |
ed77134b MG |
377 | |
378 | if (filp->private_data) | |
d82b3518 MG |
379 | return 0; |
380 | } | |
d82b3518 MG |
381 | return -EPERM; |
382 | } | |
383 | ||
384 | static int pm_qos_power_release(struct inode *inode, struct file *filp) | |
385 | { | |
ed77134b | 386 | struct pm_qos_request_list *req; |
d82b3518 | 387 | |
82f68251 | 388 | req = filp->private_data; |
ed77134b | 389 | pm_qos_remove_request(req); |
82f68251 | 390 | kfree(req); |
d82b3518 MG |
391 | |
392 | return 0; | |
393 | } | |
394 | ||
ed77134b | 395 | |
f9b9e806 TR |
396 | static ssize_t pm_qos_power_read(struct file *filp, char __user *buf, |
397 | size_t count, loff_t *f_pos) | |
398 | { | |
399 | s32 value; | |
400 | unsigned long flags; | |
401 | struct pm_qos_object *o; | |
6eab04a8 | 402 | struct pm_qos_request_list *pm_qos_req = filp->private_data; |
f9b9e806 TR |
403 | |
404 | if (!pm_qos_req) | |
405 | return -EINVAL; | |
406 | if (!pm_qos_request_active(pm_qos_req)) | |
407 | return -EINVAL; | |
408 | ||
409 | o = pm_qos_array[pm_qos_req->pm_qos_class]; | |
410 | spin_lock_irqsave(&pm_qos_lock, flags); | |
411 | value = pm_qos_get_value(o); | |
412 | spin_unlock_irqrestore(&pm_qos_lock, flags); | |
413 | ||
414 | return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32)); | |
415 | } | |
416 | ||
d82b3518 MG |
417 | static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf, |
418 | size_t count, loff_t *f_pos) | |
419 | { | |
420 | s32 value; | |
ed77134b MG |
421 | struct pm_qos_request_list *pm_qos_req; |
422 | ||
423 | if (count == sizeof(s32)) { | |
424 | if (copy_from_user(&value, buf, sizeof(s32))) | |
425 | return -EFAULT; | |
0775a60a RW |
426 | } else if (count <= 11) { /* ASCII perhaps? */ |
427 | char ascii_value[11]; | |
428 | unsigned long int ulval; | |
429 | int ret; | |
430 | ||
431 | if (copy_from_user(ascii_value, buf, count)) | |
ed77134b | 432 | return -EFAULT; |
0775a60a RW |
433 | |
434 | if (count > 10) { | |
435 | if (ascii_value[10] == '\n') | |
436 | ascii_value[10] = '\0'; | |
437 | else | |
438 | return -EINVAL; | |
439 | } else { | |
440 | ascii_value[count] = '\0'; | |
441 | } | |
442 | ret = strict_strtoul(ascii_value, 16, &ulval); | |
443 | if (ret) { | |
444 | pr_debug("%s, 0x%lx, 0x%x\n", ascii_value, ulval, ret); | |
ed77134b | 445 | return -EINVAL; |
0775a60a RW |
446 | } |
447 | value = (s32)lower_32_bits(ulval); | |
448 | } else { | |
d82b3518 | 449 | return -EINVAL; |
0775a60a | 450 | } |
d82b3518 | 451 | |
99a51792 | 452 | pm_qos_req = filp->private_data; |
ed77134b MG |
453 | pm_qos_update_request(pm_qos_req, value); |
454 | ||
455 | return count; | |
d82b3518 MG |
456 | } |
457 | ||
458 | ||
459 | static int __init pm_qos_power_init(void) | |
460 | { | |
461 | int ret = 0; | |
462 | ||
463 | ret = register_pm_qos_misc(&cpu_dma_pm_qos); | |
464 | if (ret < 0) { | |
465 | printk(KERN_ERR "pm_qos_param: cpu_dma_latency setup failed\n"); | |
466 | return ret; | |
467 | } | |
468 | ret = register_pm_qos_misc(&network_lat_pm_qos); | |
469 | if (ret < 0) { | |
470 | printk(KERN_ERR "pm_qos_param: network_latency setup failed\n"); | |
471 | return ret; | |
472 | } | |
473 | ret = register_pm_qos_misc(&network_throughput_pm_qos); | |
474 | if (ret < 0) | |
475 | printk(KERN_ERR | |
476 | "pm_qos_param: network_throughput setup failed\n"); | |
477 | ||
478 | return ret; | |
479 | } | |
480 | ||
481 | late_initcall(pm_qos_power_init); |