1
#include <net/compat.h>
3
/* This is the backport of pm-qos params for kernels <= 2.6.25 */
4
#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,25))
7
* This module exposes the interface to kernel space for specifying
8
* QoS dependencies. It provides infrastructure for registration of:
10
* Dependents on a QoS value : register requirements
11
* Watchers of QoS value : get notified when target QoS value changes
13
* This QoS design is best effort based. Dependents register their QoS needs.
14
* Watchers register to keep track of the current QoS needs of the system.
16
* There are 3 basic classes of QoS parameter: latency, timeout, throughput
17
* each have defined units:
19
* timeout: usec <-- currently not used.
20
* throughput: kbs (kilo byte / sec)
22
* There are lists of pm_qos_objects each one wrapping requirements, notifiers
24
* User mode requirements on a QOS parameter register themselves to the
25
* subsystem by opening the device node /dev/... and writing there request to
26
* the node. As long as the process holds a file handle open to the node the
27
* client continues to be accounted for. Upon file release the usermode
28
* requirement is removed and a new qos target is computed. This way when the
29
* requirement that the application has is cleaned up when closes the file
30
* pointer or exits the pm_qos_object will get an opportunity to clean up.
32
* Mark Gross <mgross@linux.intel.com>
35
#include <linux/pm_qos_params.h>
36
#include <linux/sched.h>
37
#include <linux/spinlock.h>
38
#include <linux/slab.h>
39
#include <linux/time.h>
41
#include <linux/device.h>
42
#include <linux/miscdevice.h>
43
#include <linux/string.h>
44
#include <linux/platform_device.h>
45
#include <linux/init.h>
47
#include <linux/uaccess.h>
50
* locking rule: all changes to requirements or notifiers lists
51
* or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
52
* held, taken with _irqsave. One lock to rule them all
54
struct requirement_list {
55
struct list_head list;
64
static s32 max_compare(s32 v1, s32 v2);
65
static s32 min_compare(s32 v1, s32 v2);
67
struct pm_qos_object {
68
struct requirement_list requirements;
69
struct blocking_notifier_head *notifiers;
70
struct miscdevice pm_qos_power_miscdev;
73
atomic_t target_value;
74
s32 (*comparitor)(s32, s32);
77
static struct pm_qos_object null_pm_qos;
78
static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
79
static struct pm_qos_object cpu_dma_pm_qos = {
80
.requirements = {LIST_HEAD_INIT(cpu_dma_pm_qos.requirements.list)},
81
.notifiers = &cpu_dma_lat_notifier,
82
.name = "cpu_dma_latency",
83
.default_value = 2000 * USEC_PER_SEC,
84
.target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
85
.comparitor = min_compare
88
static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
89
static struct pm_qos_object network_lat_pm_qos = {
90
.requirements = {LIST_HEAD_INIT(network_lat_pm_qos.requirements.list)},
91
.notifiers = &network_lat_notifier,
92
.name = "network_latency",
93
.default_value = 2000 * USEC_PER_SEC,
94
.target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
95
.comparitor = min_compare
99
static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
100
static struct pm_qos_object network_throughput_pm_qos = {
102
{LIST_HEAD_INIT(network_throughput_pm_qos.requirements.list)},
103
.notifiers = &network_throughput_notifier,
104
.name = "network_throughput",
106
.target_value = ATOMIC_INIT(0),
107
.comparitor = max_compare
110
static BLOCKING_NOTIFIER_HEAD(system_bus_freq_notifier);
111
static struct pm_qos_object system_bus_freq_pm_qos = {
113
{LIST_HEAD_INIT(system_bus_freq_pm_qos.requirements.list)},
114
.notifiers = &system_bus_freq_notifier,
115
.name = "system_bus_freq",
117
.target_value = ATOMIC_INIT(0),
118
.comparitor = max_compare
122
static struct pm_qos_object *pm_qos_array[PM_QOS_NUM_CLASSES] = {
123
[PM_QOS_RESERVED] = &null_pm_qos,
124
[PM_QOS_CPU_DMA_LATENCY] = &cpu_dma_pm_qos,
125
[PM_QOS_NETWORK_LATENCY] = &network_lat_pm_qos,
126
[PM_QOS_NETWORK_THROUGHPUT] = &network_throughput_pm_qos,
127
[PM_QOS_SYSTEM_BUS_FREQ] = &system_bus_freq_pm_qos,
130
static DEFINE_SPINLOCK(pm_qos_lock);
132
static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
133
size_t count, loff_t *f_pos);
134
static int pm_qos_power_open(struct inode *inode, struct file *filp);
135
static int pm_qos_power_release(struct inode *inode, struct file *filp);
137
static const struct file_operations pm_qos_power_fops = {
138
.write = pm_qos_power_write,
139
.open = pm_qos_power_open,
140
.release = pm_qos_power_release,
143
/* static helper functions */
144
static s32 max_compare(s32 v1, s32 v2)
149
static s32 min_compare(s32 v1, s32 v2)
155
static void update_target(int target)
158
struct requirement_list *node;
160
int call_notifier = 0;
162
spin_lock_irqsave(&pm_qos_lock, flags);
163
extreme_value = pm_qos_array[target]->default_value;
164
list_for_each_entry(node,
165
&pm_qos_array[target]->requirements.list, list) {
166
extreme_value = pm_qos_array[target]->comparitor(
167
extreme_value, node->value);
169
if (atomic_read(&pm_qos_array[target]->target_value) != extreme_value) {
171
atomic_set(&pm_qos_array[target]->target_value, extreme_value);
172
pr_debug(KERN_ERR "new target for qos %d is %d\n", target,
173
atomic_read(&pm_qos_array[target]->target_value));
175
spin_unlock_irqrestore(&pm_qos_lock, flags);
178
blocking_notifier_call_chain(pm_qos_array[target]->notifiers,
179
(unsigned long) extreme_value, NULL);
182
static int register_pm_qos_misc(struct pm_qos_object *qos)
184
qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR;
185
qos->pm_qos_power_miscdev.name = qos->name;
186
qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops;
188
return misc_register(&qos->pm_qos_power_miscdev);
191
static int find_pm_qos_object_by_minor(int minor)
195
for (pm_qos_class = 0;
196
pm_qos_class < PM_QOS_NUM_CLASSES; pm_qos_class++) {
198
pm_qos_array[pm_qos_class]->pm_qos_power_miscdev.minor)
205
* pm_qos_requirement - returns current system wide qos expectation
206
* @pm_qos_class: identification of which qos value is requested
208
* This function returns the current target value in an atomic manner.
210
int pm_qos_requirement(int pm_qos_class)
212
return atomic_read(&pm_qos_array[pm_qos_class]->target_value);
214
EXPORT_SYMBOL_GPL(pm_qos_requirement);
217
* pm_qos_add_requirement - inserts new qos request into the list
218
* @pm_qos_class: identifies which list of qos request to us
219
* @name: identifies the request
220
* @value: defines the qos request
222
* This function inserts a new entry in the pm_qos_class list of requested qos
223
* performance characteristics. It recomputes the aggregate QoS expectations
224
* for the pm_qos_class of parameters.
226
int pm_qos_add_requirement(int pm_qos_class, char *name, s32 value)
228
struct requirement_list *dep;
231
dep = kzalloc(sizeof(struct requirement_list), GFP_KERNEL);
233
if (value == PM_QOS_DEFAULT_VALUE)
234
dep->value = pm_qos_array[pm_qos_class]->default_value;
237
dep->name = kstrdup(name, GFP_KERNEL);
241
spin_lock_irqsave(&pm_qos_lock, flags);
243
&pm_qos_array[pm_qos_class]->requirements.list);
244
spin_unlock_irqrestore(&pm_qos_lock, flags);
245
update_target(pm_qos_class);
254
EXPORT_SYMBOL_GPL(pm_qos_add_requirement);
257
* pm_qos_update_requirement - modifies an existing qos request
258
* @pm_qos_class: identifies which list of qos request to us
259
* @name: identifies the request
260
* @value: defines the qos request
262
* Updates an existing qos requirement for the pm_qos_class of parameters along
263
* with updating the target pm_qos_class value.
265
* If the named request isn't in the list then no change is made.
267
int pm_qos_update_requirement(int pm_qos_class, char *name, s32 new_value)
270
struct requirement_list *node;
271
int pending_update = 0;
273
spin_lock_irqsave(&pm_qos_lock, flags);
274
list_for_each_entry(node,
275
&pm_qos_array[pm_qos_class]->requirements.list, list) {
276
if (strcmp(node->name, name) == 0) {
277
if (new_value == PM_QOS_DEFAULT_VALUE)
279
pm_qos_array[pm_qos_class]->default_value;
281
node->value = new_value;
286
spin_unlock_irqrestore(&pm_qos_lock, flags);
288
update_target(pm_qos_class);
292
EXPORT_SYMBOL_GPL(pm_qos_update_requirement);
295
* pm_qos_remove_requirement - modifies an existing qos request
296
* @pm_qos_class: identifies which list of qos request to us
297
* @name: identifies the request
299
* Will remove named qos request from pm_qos_class list of parameters and
300
* recompute the current target value for the pm_qos_class.
302
void pm_qos_remove_requirement(int pm_qos_class, char *name)
305
struct requirement_list *node;
306
int pending_update = 0;
308
spin_lock_irqsave(&pm_qos_lock, flags);
309
list_for_each_entry(node,
310
&pm_qos_array[pm_qos_class]->requirements.list, list) {
311
if (strcmp(node->name, name) == 0) {
313
list_del(&node->list);
319
spin_unlock_irqrestore(&pm_qos_lock, flags);
321
update_target(pm_qos_class);
323
EXPORT_SYMBOL_GPL(pm_qos_remove_requirement);
326
* pm_qos_add_notifier - sets notification entry for changes to target value
327
* @pm_qos_class: identifies which qos target changes should be notified.
328
* @notifier: notifier block managed by caller.
330
* will register the notifier into a notification chain that gets called
331
* upon changes to the pm_qos_class target value.
333
int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
337
retval = blocking_notifier_chain_register(
338
pm_qos_array[pm_qos_class]->notifiers, notifier);
342
EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
345
* pm_qos_remove_notifier - deletes notification entry from chain.
346
* @pm_qos_class: identifies which qos target changes are notified.
347
* @notifier: notifier block to be removed.
349
* will remove the notifier from the notification chain that gets called
350
* upon changes to the pm_qos_class target value.
352
int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
356
retval = blocking_notifier_chain_unregister(
357
pm_qos_array[pm_qos_class]->notifiers, notifier);
361
EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
363
#define PID_NAME_LEN 32
365
static int pm_qos_power_open(struct inode *inode, struct file *filp)
369
char name[PID_NAME_LEN];
371
pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
372
if (pm_qos_class >= 0) {
373
filp->private_data = (void *)pm_qos_class;
374
snprintf(name, PID_NAME_LEN, "process_%d", current->pid);
375
ret = pm_qos_add_requirement(pm_qos_class, name,
376
PM_QOS_DEFAULT_VALUE);
383
static int pm_qos_power_release(struct inode *inode, struct file *filp)
386
char name[PID_NAME_LEN];
388
pm_qos_class = (long)filp->private_data;
389
snprintf(name, PID_NAME_LEN, "process_%d", current->pid);
390
pm_qos_remove_requirement(pm_qos_class, name);
395
static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
396
size_t count, loff_t *f_pos)
400
char name[PID_NAME_LEN];
402
pm_qos_class = (long)filp->private_data;
403
if (count != sizeof(s32))
405
if (copy_from_user(&value, buf, sizeof(s32)))
407
snprintf(name, PID_NAME_LEN, "process_%d", current->pid);
408
pm_qos_update_requirement(pm_qos_class, name, value);
415
* This initializes pm-qos for older kernels.
417
int compat_pm_qos_power_init(void)
421
ret = register_pm_qos_misc(&cpu_dma_pm_qos);
423
printk(KERN_ERR "pm_qos_param: cpu_dma_latency setup failed\n");
426
ret = register_pm_qos_misc(&network_lat_pm_qos);
428
printk(KERN_ERR "pm_qos_param: network_latency setup failed\n");
431
ret = register_pm_qos_misc(&network_throughput_pm_qos);
434
"pm_qos_param: network_throughput setup failed\n");
437
ret = register_pm_qos_misc(&system_bus_freq_pm_qos);
440
"pm_qos_param: system_bus_freq setup failed\n");
445
int compat_pm_qos_power_deinit(void)
449
ret = misc_deregister(&cpu_dma_pm_qos.pm_qos_power_miscdev);
451
printk(KERN_ERR "pm_qos_param: cpu_dma_latency deinit failed\n");
455
ret = misc_deregister(&network_lat_pm_qos.pm_qos_power_miscdev);
457
printk(KERN_ERR "pm_qos_param: network_latency deinit failed\n");
461
ret = misc_deregister(&network_throughput_pm_qos.pm_qos_power_miscdev);
464
"pm_qos_param: network_throughput deinit failed\n");
468
ret = misc_deregister(&system_bus_freq_pm_qos.pm_qos_power_miscdev);
471
"pm_qos_param: system_bus_freq deinit failed\n");
477
#endif /* LINUX_VERSION_CODE < KERNEL_VERSION(2,6,25) */