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> | |
43 | ||
44 | #include <linux/uaccess.h> | |
45 | ||
46 | /* | |
ed77134b | 47 | * locking rule: all changes to requests or notifiers lists |
d82b3518 MG |
48 | * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock |
49 | * held, taken with _irqsave. One lock to rule them all | |
50 | */ | |
5f279845 JB |
51 | enum pm_qos_type { |
52 | PM_QOS_MAX, /* return the largest value */ | |
53 | PM_QOS_MIN /* return the smallest value */ | |
54 | }; | |
d82b3518 MG |
55 | |
56 | struct pm_qos_object { | |
5f279845 | 57 | struct plist_head requests; |
d82b3518 MG |
58 | struct blocking_notifier_head *notifiers; |
59 | struct miscdevice pm_qos_power_miscdev; | |
60 | char *name; | |
61 | s32 default_value; | |
5f279845 | 62 | enum pm_qos_type type; |
d82b3518 MG |
63 | }; |
64 | ||
5f279845 JB |
65 | static DEFINE_SPINLOCK(pm_qos_lock); |
66 | ||
d82b3518 MG |
67 | static struct pm_qos_object null_pm_qos; |
68 | static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier); | |
69 | static struct pm_qos_object cpu_dma_pm_qos = { | |
5f279845 | 70 | .requests = PLIST_HEAD_INIT(cpu_dma_pm_qos.requests, pm_qos_lock), |
d82b3518 MG |
71 | .notifiers = &cpu_dma_lat_notifier, |
72 | .name = "cpu_dma_latency", | |
73 | .default_value = 2000 * USEC_PER_SEC, | |
5f279845 | 74 | .type = PM_QOS_MIN, |
d82b3518 MG |
75 | }; |
76 | ||
77 | static BLOCKING_NOTIFIER_HEAD(network_lat_notifier); | |
78 | static struct pm_qos_object network_lat_pm_qos = { | |
5f279845 | 79 | .requests = PLIST_HEAD_INIT(network_lat_pm_qos.requests, pm_qos_lock), |
d82b3518 MG |
80 | .notifiers = &network_lat_notifier, |
81 | .name = "network_latency", | |
82 | .default_value = 2000 * USEC_PER_SEC, | |
5f279845 | 83 | .type = PM_QOS_MIN |
d82b3518 MG |
84 | }; |
85 | ||
86 | ||
87 | static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier); | |
88 | static struct pm_qos_object network_throughput_pm_qos = { | |
5f279845 | 89 | .requests = PLIST_HEAD_INIT(network_throughput_pm_qos.requests, pm_qos_lock), |
d82b3518 MG |
90 | .notifiers = &network_throughput_notifier, |
91 | .name = "network_throughput", | |
92 | .default_value = 0, | |
5f279845 | 93 | .type = PM_QOS_MAX, |
d82b3518 MG |
94 | }; |
95 | ||
96 | ||
97 | static struct pm_qos_object *pm_qos_array[] = { | |
98 | &null_pm_qos, | |
99 | &cpu_dma_pm_qos, | |
100 | &network_lat_pm_qos, | |
101 | &network_throughput_pm_qos | |
102 | }; | |
103 | ||
d82b3518 MG |
104 | static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf, |
105 | size_t count, loff_t *f_pos); | |
f9b9e806 TR |
106 | static ssize_t pm_qos_power_read(struct file *filp, char __user *buf, |
107 | size_t count, loff_t *f_pos); | |
d82b3518 MG |
108 | static int pm_qos_power_open(struct inode *inode, struct file *filp); |
109 | static int pm_qos_power_release(struct inode *inode, struct file *filp); | |
110 | ||
111 | static const struct file_operations pm_qos_power_fops = { | |
112 | .write = pm_qos_power_write, | |
f9b9e806 | 113 | .read = pm_qos_power_read, |
d82b3518 MG |
114 | .open = pm_qos_power_open, |
115 | .release = pm_qos_power_release, | |
6038f373 | 116 | .llseek = noop_llseek, |
d82b3518 MG |
117 | }; |
118 | ||
5f279845 JB |
119 | /* unlocked internal variant */ |
120 | static inline int pm_qos_get_value(struct pm_qos_object *o) | |
d82b3518 | 121 | { |
5f279845 JB |
122 | if (plist_head_empty(&o->requests)) |
123 | return o->default_value; | |
d82b3518 | 124 | |
5f279845 JB |
125 | switch (o->type) { |
126 | case PM_QOS_MIN: | |
00fafcda | 127 | return plist_first(&o->requests)->prio; |
d82b3518 | 128 | |
5f279845 | 129 | case PM_QOS_MAX: |
00fafcda | 130 | return plist_last(&o->requests)->prio; |
d82b3518 | 131 | |
5f279845 JB |
132 | default: |
133 | /* runtime check for not using enum */ | |
134 | BUG(); | |
135 | } | |
136 | } | |
137 | ||
138 | static void update_target(struct pm_qos_object *o, struct plist_node *node, | |
139 | int del, int value) | |
d82b3518 | 140 | { |
d82b3518 | 141 | unsigned long flags; |
5f279845 | 142 | int prev_value, curr_value; |
d82b3518 MG |
143 | |
144 | spin_lock_irqsave(&pm_qos_lock, flags); | |
5f279845 JB |
145 | prev_value = pm_qos_get_value(o); |
146 | /* PM_QOS_DEFAULT_VALUE is a signal that the value is unchanged */ | |
147 | if (value != PM_QOS_DEFAULT_VALUE) { | |
148 | /* | |
149 | * to change the list, we atomically remove, reinit | |
150 | * with new value and add, then see if the extremal | |
151 | * changed | |
152 | */ | |
153 | plist_del(node, &o->requests); | |
154 | plist_node_init(node, value); | |
155 | plist_add(node, &o->requests); | |
156 | } else if (del) { | |
157 | plist_del(node, &o->requests); | |
158 | } else { | |
159 | plist_add(node, &o->requests); | |
d82b3518 | 160 | } |
5f279845 | 161 | curr_value = pm_qos_get_value(o); |
d82b3518 MG |
162 | spin_unlock_irqrestore(&pm_qos_lock, flags); |
163 | ||
5f279845 JB |
164 | if (prev_value != curr_value) |
165 | blocking_notifier_call_chain(o->notifiers, | |
166 | (unsigned long)curr_value, | |
167 | NULL); | |
d82b3518 MG |
168 | } |
169 | ||
170 | static int register_pm_qos_misc(struct pm_qos_object *qos) | |
171 | { | |
172 | qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR; | |
173 | qos->pm_qos_power_miscdev.name = qos->name; | |
174 | qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops; | |
175 | ||
176 | return misc_register(&qos->pm_qos_power_miscdev); | |
177 | } | |
178 | ||
179 | static int find_pm_qos_object_by_minor(int minor) | |
180 | { | |
181 | int pm_qos_class; | |
182 | ||
183 | for (pm_qos_class = 0; | |
184 | pm_qos_class < PM_QOS_NUM_CLASSES; pm_qos_class++) { | |
185 | if (minor == | |
186 | pm_qos_array[pm_qos_class]->pm_qos_power_miscdev.minor) | |
187 | return pm_qos_class; | |
188 | } | |
189 | return -1; | |
190 | } | |
191 | ||
192 | /** | |
ed77134b | 193 | * pm_qos_request - returns current system wide qos expectation |
d82b3518 MG |
194 | * @pm_qos_class: identification of which qos value is requested |
195 | * | |
196 | * This function returns the current target value in an atomic manner. | |
197 | */ | |
ed77134b | 198 | int pm_qos_request(int pm_qos_class) |
d82b3518 | 199 | { |
5f279845 JB |
200 | unsigned long flags; |
201 | int value; | |
202 | ||
203 | spin_lock_irqsave(&pm_qos_lock, flags); | |
204 | value = pm_qos_get_value(pm_qos_array[pm_qos_class]); | |
205 | spin_unlock_irqrestore(&pm_qos_lock, flags); | |
206 | ||
207 | return value; | |
d82b3518 | 208 | } |
ed77134b | 209 | EXPORT_SYMBOL_GPL(pm_qos_request); |
d82b3518 | 210 | |
82f68251 JB |
211 | int pm_qos_request_active(struct pm_qos_request_list *req) |
212 | { | |
213 | return req->pm_qos_class != 0; | |
214 | } | |
215 | EXPORT_SYMBOL_GPL(pm_qos_request_active); | |
216 | ||
d82b3518 | 217 | /** |
ed77134b | 218 | * pm_qos_add_request - inserts new qos request into the list |
25cc69ec SK |
219 | * @dep: pointer to a preallocated handle |
220 | * @pm_qos_class: identifies which list of qos request to use | |
d82b3518 MG |
221 | * @value: defines the qos request |
222 | * | |
223 | * This function inserts a new entry in the pm_qos_class list of requested qos | |
bf1db69f | 224 | * performance characteristics. It recomputes the aggregate QoS expectations |
25cc69ec SK |
225 | * for the pm_qos_class of parameters and initializes the pm_qos_request_list |
226 | * handle. Caller needs to save this handle for later use in updates and | |
227 | * removal. | |
d82b3518 | 228 | */ |
25cc69ec | 229 | |
82f68251 JB |
230 | void pm_qos_add_request(struct pm_qos_request_list *dep, |
231 | int pm_qos_class, s32 value) | |
d82b3518 | 232 | { |
82f68251 JB |
233 | struct pm_qos_object *o = pm_qos_array[pm_qos_class]; |
234 | int new_value; | |
d82b3518 | 235 | |
82f68251 JB |
236 | if (pm_qos_request_active(dep)) { |
237 | WARN(1, KERN_ERR "pm_qos_add_request() called for already added request\n"); | |
238 | return; | |
239 | } | |
240 | if (value == PM_QOS_DEFAULT_VALUE) | |
241 | new_value = o->default_value; | |
242 | else | |
243 | new_value = value; | |
244 | plist_node_init(&dep->list, new_value); | |
245 | dep->pm_qos_class = pm_qos_class; | |
246 | update_target(o, &dep->list, 0, PM_QOS_DEFAULT_VALUE); | |
d82b3518 | 247 | } |
ed77134b | 248 | EXPORT_SYMBOL_GPL(pm_qos_add_request); |
d82b3518 MG |
249 | |
250 | /** | |
ed77134b MG |
251 | * pm_qos_update_request - modifies an existing qos request |
252 | * @pm_qos_req : handle to list element holding a pm_qos request to use | |
d82b3518 MG |
253 | * @value: defines the qos request |
254 | * | |
ed77134b | 255 | * Updates an existing qos request for the pm_qos_class of parameters along |
d82b3518 MG |
256 | * with updating the target pm_qos_class value. |
257 | * | |
ed77134b | 258 | * Attempts are made to make this code callable on hot code paths. |
d82b3518 | 259 | */ |
ed77134b | 260 | void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req, |
5f279845 | 261 | s32 new_value) |
d82b3518 | 262 | { |
ed77134b | 263 | s32 temp; |
5f279845 | 264 | struct pm_qos_object *o; |
d82b3518 | 265 | |
5f279845 JB |
266 | if (!pm_qos_req) /*guard against callers passing in null */ |
267 | return; | |
268 | ||
82f68251 JB |
269 | if (!pm_qos_request_active(pm_qos_req)) { |
270 | WARN(1, KERN_ERR "pm_qos_update_request() called for unknown object\n"); | |
271 | return; | |
272 | } | |
273 | ||
5f279845 JB |
274 | o = pm_qos_array[pm_qos_req->pm_qos_class]; |
275 | ||
276 | if (new_value == PM_QOS_DEFAULT_VALUE) | |
277 | temp = o->default_value; | |
278 | else | |
279 | temp = new_value; | |
280 | ||
281 | if (temp != pm_qos_req->list.prio) | |
282 | update_target(o, &pm_qos_req->list, 0, temp); | |
d82b3518 | 283 | } |
ed77134b | 284 | EXPORT_SYMBOL_GPL(pm_qos_update_request); |
d82b3518 MG |
285 | |
286 | /** | |
ed77134b MG |
287 | * pm_qos_remove_request - modifies an existing qos request |
288 | * @pm_qos_req: handle to request list element | |
d82b3518 | 289 | * |
ed77134b MG |
290 | * Will remove pm qos request from the list of requests and |
291 | * recompute the current target value for the pm_qos_class. Call this | |
292 | * on slow code paths. | |
d82b3518 | 293 | */ |
ed77134b | 294 | void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req) |
d82b3518 | 295 | { |
5f279845 | 296 | struct pm_qos_object *o; |
ed77134b MG |
297 | |
298 | if (pm_qos_req == NULL) | |
299 | return; | |
300 | /* silent return to keep pcm code cleaner */ | |
d82b3518 | 301 | |
82f68251 JB |
302 | if (!pm_qos_request_active(pm_qos_req)) { |
303 | WARN(1, KERN_ERR "pm_qos_remove_request() called for unknown object\n"); | |
304 | return; | |
305 | } | |
306 | ||
5f279845 JB |
307 | o = pm_qos_array[pm_qos_req->pm_qos_class]; |
308 | update_target(o, &pm_qos_req->list, 1, PM_QOS_DEFAULT_VALUE); | |
82f68251 | 309 | memset(pm_qos_req, 0, sizeof(*pm_qos_req)); |
d82b3518 | 310 | } |
ed77134b | 311 | EXPORT_SYMBOL_GPL(pm_qos_remove_request); |
d82b3518 MG |
312 | |
313 | /** | |
314 | * pm_qos_add_notifier - sets notification entry for changes to target value | |
315 | * @pm_qos_class: identifies which qos target changes should be notified. | |
316 | * @notifier: notifier block managed by caller. | |
317 | * | |
318 | * will register the notifier into a notification chain that gets called | |
bf1db69f | 319 | * upon changes to the pm_qos_class target value. |
d82b3518 | 320 | */ |
ed77134b | 321 | int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier) |
d82b3518 MG |
322 | { |
323 | int retval; | |
324 | ||
325 | retval = blocking_notifier_chain_register( | |
326 | pm_qos_array[pm_qos_class]->notifiers, notifier); | |
327 | ||
328 | return retval; | |
329 | } | |
330 | EXPORT_SYMBOL_GPL(pm_qos_add_notifier); | |
331 | ||
332 | /** | |
333 | * pm_qos_remove_notifier - deletes notification entry from chain. | |
334 | * @pm_qos_class: identifies which qos target changes are notified. | |
335 | * @notifier: notifier block to be removed. | |
336 | * | |
337 | * will remove the notifier from the notification chain that gets called | |
bf1db69f | 338 | * upon changes to the pm_qos_class target value. |
d82b3518 MG |
339 | */ |
340 | int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier) | |
341 | { | |
342 | int retval; | |
343 | ||
344 | retval = blocking_notifier_chain_unregister( | |
345 | pm_qos_array[pm_qos_class]->notifiers, notifier); | |
346 | ||
347 | return retval; | |
348 | } | |
349 | EXPORT_SYMBOL_GPL(pm_qos_remove_notifier); | |
350 | ||
d82b3518 MG |
351 | static int pm_qos_power_open(struct inode *inode, struct file *filp) |
352 | { | |
d82b3518 MG |
353 | long pm_qos_class; |
354 | ||
355 | pm_qos_class = find_pm_qos_object_by_minor(iminor(inode)); | |
356 | if (pm_qos_class >= 0) { | |
bac1e74d | 357 | struct pm_qos_request_list *req = kzalloc(sizeof(*req), GFP_KERNEL); |
82f68251 JB |
358 | if (!req) |
359 | return -ENOMEM; | |
360 | ||
361 | pm_qos_add_request(req, pm_qos_class, PM_QOS_DEFAULT_VALUE); | |
362 | filp->private_data = req; | |
ed77134b MG |
363 | |
364 | if (filp->private_data) | |
d82b3518 MG |
365 | return 0; |
366 | } | |
d82b3518 MG |
367 | return -EPERM; |
368 | } | |
369 | ||
370 | static int pm_qos_power_release(struct inode *inode, struct file *filp) | |
371 | { | |
ed77134b | 372 | struct pm_qos_request_list *req; |
d82b3518 | 373 | |
82f68251 | 374 | req = filp->private_data; |
ed77134b | 375 | pm_qos_remove_request(req); |
82f68251 | 376 | kfree(req); |
d82b3518 MG |
377 | |
378 | return 0; | |
379 | } | |
380 | ||
ed77134b | 381 | |
f9b9e806 TR |
382 | static ssize_t pm_qos_power_read(struct file *filp, char __user *buf, |
383 | size_t count, loff_t *f_pos) | |
384 | { | |
385 | s32 value; | |
386 | unsigned long flags; | |
387 | struct pm_qos_object *o; | |
388 | struct pm_qos_request_list *pm_qos_req = filp->private_data;; | |
389 | ||
390 | if (!pm_qos_req) | |
391 | return -EINVAL; | |
392 | if (!pm_qos_request_active(pm_qos_req)) | |
393 | return -EINVAL; | |
394 | ||
395 | o = pm_qos_array[pm_qos_req->pm_qos_class]; | |
396 | spin_lock_irqsave(&pm_qos_lock, flags); | |
397 | value = pm_qos_get_value(o); | |
398 | spin_unlock_irqrestore(&pm_qos_lock, flags); | |
399 | ||
400 | return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32)); | |
401 | } | |
402 | ||
d82b3518 MG |
403 | static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf, |
404 | size_t count, loff_t *f_pos) | |
405 | { | |
406 | s32 value; | |
ed77134b MG |
407 | int x; |
408 | char ascii_value[11]; | |
409 | struct pm_qos_request_list *pm_qos_req; | |
410 | ||
411 | if (count == sizeof(s32)) { | |
412 | if (copy_from_user(&value, buf, sizeof(s32))) | |
413 | return -EFAULT; | |
414 | } else if (count == 11) { /* len('0x12345678/0') */ | |
415 | if (copy_from_user(ascii_value, buf, 11)) | |
416 | return -EFAULT; | |
0109c2c4 | 417 | if (strlen(ascii_value) != 10) |
418 | return -EINVAL; | |
ed77134b MG |
419 | x = sscanf(ascii_value, "%x", &value); |
420 | if (x != 1) | |
421 | return -EINVAL; | |
0109c2c4 | 422 | pr_debug("%s, %d, 0x%x\n", ascii_value, x, value); |
ed77134b | 423 | } else |
d82b3518 | 424 | return -EINVAL; |
d82b3518 | 425 | |
99a51792 | 426 | pm_qos_req = filp->private_data; |
ed77134b MG |
427 | pm_qos_update_request(pm_qos_req, value); |
428 | ||
429 | return count; | |
d82b3518 MG |
430 | } |
431 | ||
432 | ||
433 | static int __init pm_qos_power_init(void) | |
434 | { | |
435 | int ret = 0; | |
436 | ||
437 | ret = register_pm_qos_misc(&cpu_dma_pm_qos); | |
438 | if (ret < 0) { | |
439 | printk(KERN_ERR "pm_qos_param: cpu_dma_latency setup failed\n"); | |
440 | return ret; | |
441 | } | |
442 | ret = register_pm_qos_misc(&network_lat_pm_qos); | |
443 | if (ret < 0) { | |
444 | printk(KERN_ERR "pm_qos_param: network_latency setup failed\n"); | |
445 | return ret; | |
446 | } | |
447 | ret = register_pm_qos_misc(&network_throughput_pm_qos); | |
448 | if (ret < 0) | |
449 | printk(KERN_ERR | |
450 | "pm_qos_param: network_throughput setup failed\n"); | |
451 | ||
452 | return ret; | |
453 | } | |
454 | ||
455 | late_initcall(pm_qos_power_init); |