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