crypto: omap-aes - initialize aes module once per request
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / pm_qos_params.c
blobc7a8f453919e65a42e0251b968a2d3652e0a4c3a
1 /*
2 * This module exposes the interface to kernel space for specifying
3 * QoS dependencies. It provides infrastructure for registration of:
5 * Dependents on a QoS value : register requests
6 * Watchers of QoS value : get notified when target QoS value changes
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.
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)
17 * There are lists of pm_qos_objects each one wrapping requests, notifiers
19 * User mode requests on a QOS parameter register themselves to the
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
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
25 * pointer or exits the pm_qos_object will get an opportunity to clean up.
27 * Mark Gross <mgross@linux.intel.com>
30 /*#define DEBUG*/
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>
44 #include <linux/uaccess.h>
47 * locking rule: all changes to requests or notifiers lists
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
51 enum pm_qos_type {
52 PM_QOS_MAX, /* return the largest value */
53 PM_QOS_MIN /* return the smallest value */
56 struct pm_qos_object {
57 struct plist_head requests;
58 struct blocking_notifier_head *notifiers;
59 struct miscdevice pm_qos_power_miscdev;
60 char *name;
61 s32 default_value;
62 enum pm_qos_type type;
65 static DEFINE_SPINLOCK(pm_qos_lock);
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 = {
70 .requests = PLIST_HEAD_INIT(cpu_dma_pm_qos.requests, pm_qos_lock),
71 .notifiers = &cpu_dma_lat_notifier,
72 .name = "cpu_dma_latency",
73 .default_value = 2000 * USEC_PER_SEC,
74 .type = PM_QOS_MIN,
77 static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
78 static struct pm_qos_object network_lat_pm_qos = {
79 .requests = PLIST_HEAD_INIT(network_lat_pm_qos.requests, pm_qos_lock),
80 .notifiers = &network_lat_notifier,
81 .name = "network_latency",
82 .default_value = 2000 * USEC_PER_SEC,
83 .type = PM_QOS_MIN
87 static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
88 static struct pm_qos_object network_throughput_pm_qos = {
89 .requests = PLIST_HEAD_INIT(network_throughput_pm_qos.requests, pm_qos_lock),
90 .notifiers = &network_throughput_notifier,
91 .name = "network_throughput",
92 .default_value = 0,
93 .type = PM_QOS_MAX,
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
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);
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,
113 .llseek = noop_llseek,
116 /* unlocked internal variant */
117 static inline int pm_qos_get_value(struct pm_qos_object *o)
119 if (plist_head_empty(&o->requests))
120 return o->default_value;
122 switch (o->type) {
123 case PM_QOS_MIN:
124 return plist_last(&o->requests)->prio;
126 case PM_QOS_MAX:
127 return plist_first(&o->requests)->prio;
129 default:
130 /* runtime check for not using enum */
131 BUG();
135 static void update_target(struct pm_qos_object *o, struct plist_node *node,
136 int del, int value)
138 unsigned long flags;
139 int prev_value, curr_value;
141 spin_lock_irqsave(&pm_qos_lock, flags);
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) {
146 * to change the list, we atomically remove, reinit
147 * with new value and add, then see if the extremal
148 * changed
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);
158 curr_value = pm_qos_get_value(o);
159 spin_unlock_irqrestore(&pm_qos_lock, flags);
161 if (prev_value != curr_value)
162 blocking_notifier_call_chain(o->notifiers,
163 (unsigned long)curr_value,
164 NULL);
167 static int register_pm_qos_misc(struct pm_qos_object *qos)
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;
173 return misc_register(&qos->pm_qos_power_miscdev);
176 static int find_pm_qos_object_by_minor(int minor)
178 int pm_qos_class;
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;
186 return -1;
190 * pm_qos_request - returns current system wide qos expectation
191 * @pm_qos_class: identification of which qos value is requested
193 * This function returns the current target value in an atomic manner.
195 int pm_qos_request(int pm_qos_class)
197 unsigned long flags;
198 int value;
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);
204 return value;
206 EXPORT_SYMBOL_GPL(pm_qos_request);
208 int pm_qos_request_active(struct pm_qos_request_list *req)
210 return req->pm_qos_class != 0;
212 EXPORT_SYMBOL_GPL(pm_qos_request_active);
215 * pm_qos_add_request - inserts new qos request into the list
216 * @dep: pointer to a preallocated handle
217 * @pm_qos_class: identifies which list of qos request to use
218 * @value: defines the qos request
220 * This function inserts a new entry in the pm_qos_class list of requested qos
221 * performance characteristics. It recomputes the aggregate QoS expectations
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.
227 void pm_qos_add_request(struct pm_qos_request_list *dep,
228 int pm_qos_class, s32 value)
230 struct pm_qos_object *o = pm_qos_array[pm_qos_class];
231 int new_value;
233 if (pm_qos_request_active(dep)) {
234 WARN(1, KERN_ERR "pm_qos_add_request() called for already added request\n");
235 return;
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);
245 EXPORT_SYMBOL_GPL(pm_qos_add_request);
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
250 * @value: defines the qos request
252 * Updates an existing qos request for the pm_qos_class of parameters along
253 * with updating the target pm_qos_class value.
255 * Attempts are made to make this code callable on hot code paths.
257 void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
258 s32 new_value)
260 s32 temp;
261 struct pm_qos_object *o;
263 if (!pm_qos_req) /*guard against callers passing in null */
264 return;
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;
271 o = pm_qos_array[pm_qos_req->pm_qos_class];
273 if (new_value == PM_QOS_DEFAULT_VALUE)
274 temp = o->default_value;
275 else
276 temp = new_value;
278 if (temp != pm_qos_req->list.prio)
279 update_target(o, &pm_qos_req->list, 0, temp);
281 EXPORT_SYMBOL_GPL(pm_qos_update_request);
284 * pm_qos_remove_request - modifies an existing qos request
285 * @pm_qos_req: handle to request list element
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.
291 void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req)
293 struct pm_qos_object *o;
295 if (pm_qos_req == NULL)
296 return;
297 /* silent return to keep pcm code cleaner */
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;
304 o = pm_qos_array[pm_qos_req->pm_qos_class];
305 update_target(o, &pm_qos_req->list, 1, PM_QOS_DEFAULT_VALUE);
306 memset(pm_qos_req, 0, sizeof(*pm_qos_req));
308 EXPORT_SYMBOL_GPL(pm_qos_remove_request);
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.
315 * will register the notifier into a notification chain that gets called
316 * upon changes to the pm_qos_class target value.
318 int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
320 int retval;
322 retval = blocking_notifier_chain_register(
323 pm_qos_array[pm_qos_class]->notifiers, notifier);
325 return retval;
327 EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
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.
334 * will remove the notifier from the notification chain that gets called
335 * upon changes to the pm_qos_class target value.
337 int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
339 int retval;
341 retval = blocking_notifier_chain_unregister(
342 pm_qos_array[pm_qos_class]->notifiers, notifier);
344 return retval;
346 EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
348 static int pm_qos_power_open(struct inode *inode, struct file *filp)
350 long pm_qos_class;
352 pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
353 if (pm_qos_class >= 0) {
354 struct pm_qos_request_list *req = kzalloc(sizeof(*req), GFP_KERNEL);
355 if (!req)
356 return -ENOMEM;
358 pm_qos_add_request(req, pm_qos_class, PM_QOS_DEFAULT_VALUE);
359 filp->private_data = req;
361 if (filp->private_data)
362 return 0;
364 return -EPERM;
367 static int pm_qos_power_release(struct inode *inode, struct file *filp)
369 struct pm_qos_request_list *req;
371 req = filp->private_data;
372 pm_qos_remove_request(req);
373 kfree(req);
375 return 0;
379 static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
380 size_t count, loff_t *f_pos)
382 s32 value;
383 int x;
384 char ascii_value[11];
385 struct pm_qos_request_list *pm_qos_req;
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;
393 if (strlen(ascii_value) != 10)
394 return -EINVAL;
395 x = sscanf(ascii_value, "%x", &value);
396 if (x != 1)
397 return -EINVAL;
398 pr_debug("%s, %d, 0x%x\n", ascii_value, x, value);
399 } else
400 return -EINVAL;
402 pm_qos_req = filp->private_data;
403 pm_qos_update_request(pm_qos_req, value);
405 return count;
409 static int __init pm_qos_power_init(void)
411 int ret = 0;
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;
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;
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");
428 return ret;
431 late_initcall(pm_qos_power_init);