[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / pm_qos_params.c

/*
 * This module exposes the interface to kernel space for specifying
 * QoS dependencies.  It provides infrastructure for registration of:
 *
 * Dependents on a QoS value : register requirements
 * Watchers of QoS value : get notified when target QoS value changes
 *
 * This QoS design is best effort based.  Dependents register their QoS needs.
 * Watchers register to keep track of the current QoS needs of the system.
 *
 * There are 3 basic classes of QoS parameter: latency, timeout, throughput
 * each have defined units:
 * latency: usec
 * timeout: usec <-- currently not used.
 * throughput: kbs (kilo byte / sec)
 *
 * There are lists of pm_qos_objects each one wrapping requirements, notifiers
 *
 * User mode requirements on a QOS parameter register themselves to the
 * subsystem by opening the device node /dev/... and writing there request to
 * the node.  As long as the process holds a file handle open to the node the
 * client continues to be accounted for.  Upon file release the usermode
 * requirement is removed and a new qos target is computed.  This way when the
 * requirement that the application has is cleaned up when closes the file
 * pointer or exits the pm_qos_object will get an opportunity to clean up.
 *
 * Mark Gross <mgross@linux.intel.com>
 */

#include <linux/pm_qos_params.h>
#include <linux/sched.h>
#include <linux/smp_lock.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/miscdevice.h>
#include <linux/string.h>
#include <linux/platform_device.h>
#include <linux/init.h>

#include <linux/uaccess.h>

/*
 * locking rule: all changes to target_value or requirements or notifiers lists
 * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
 * held, taken with _irqsave.  One lock to rule them all
 */
struct requirement_list {
	struct list_head list;
	union {
		s32 value;
		s32 usec;
		s32 kbps;
	};
	char *name;
};

static s32 max_compare(s32 v1, s32 v2);
static s32 min_compare(s32 v1, s32 v2);

struct pm_qos_object {
	struct requirement_list requirements;
	struct blocking_notifier_head *notifiers;
	struct miscdevice pm_qos_power_miscdev;
	char *name;
	s32 default_value;
	s32 target_value;
	s32 (*comparitor)(s32, s32);
};

static struct pm_qos_object null_pm_qos;
static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
static struct pm_qos_object cpu_dma_pm_qos = {
	.requirements = {LIST_HEAD_INIT(cpu_dma_pm_qos.requirements.list)},
	.notifiers = &cpu_dma_lat_notifier,
	.name = "cpu_dma_latency",
	.default_value = 2000 * USEC_PER_SEC,
	.target_value = 2000 * USEC_PER_SEC,
	.comparitor = min_compare
};

static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
static struct pm_qos_object network_lat_pm_qos = {
	.requirements = {LIST_HEAD_INIT(network_lat_pm_qos.requirements.list)},
	.notifiers = &network_lat_notifier,
	.name = "network_latency",
	.default_value = 2000 * USEC_PER_SEC,
	.target_value = 2000 * USEC_PER_SEC,
	.comparitor = min_compare
};


static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
static struct pm_qos_object network_throughput_pm_qos = {
	.requirements =
		{LIST_HEAD_INIT(network_throughput_pm_qos.requirements.list)},
	.notifiers = &network_throughput_notifier,
	.name = "network_throughput",
	.default_value = 0,
	.target_value = 0,
	.comparitor = max_compare
};


static struct pm_qos_object *pm_qos_array[] = {
	&null_pm_qos,
	&cpu_dma_pm_qos,
	&network_lat_pm_qos,
	&network_throughput_pm_qos
};

static DEFINE_SPINLOCK(pm_qos_lock);

static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
		size_t count, loff_t *f_pos);
static int pm_qos_power_open(struct inode *inode, struct file *filp);
static int pm_qos_power_release(struct inode *inode, struct file *filp);

static const struct file_operations pm_qos_power_fops = {
	.write = pm_qos_power_write,
	.open = pm_qos_power_open,
	.release = pm_qos_power_release,
};

/* static helper functions */
static s32 max_compare(s32 v1, s32 v2)
{
	return max(v1, v2);
}

static s32 min_compare(s32 v1, s32 v2)
{
	return min(v1, v2);
}


static void update_target(int target)
{
	s32 extreme_value;
	struct requirement_list *node;
	unsigned long flags;
	int call_notifier = 0;

	spin_lock_irqsave(&pm_qos_lock, flags);
	extreme_value = pm_qos_array[target]->default_value;
	list_for_each_entry(node,
			&pm_qos_array[target]->requirements.list, list) {
		extreme_value = pm_qos_array[target]->comparitor(
				extreme_value, node->value);
	}
	if (pm_qos_array[target]->target_value != extreme_value) {
		call_notifier = 1;
		pm_qos_array[target]->target_value = extreme_value;
		pr_debug(KERN_ERR "new target for qos %d is %d\n", target,
			pm_qos_array[target]->target_value);
	}
	spin_unlock_irqrestore(&pm_qos_lock, flags);

	if (call_notifier)
		blocking_notifier_call_chain(pm_qos_array[target]->notifiers,
			(unsigned long) extreme_value, NULL);
}

static int register_pm_qos_misc(struct pm_qos_object *qos)
{
	qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR;
	qos->pm_qos_power_miscdev.name = qos->name;
	qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops;

	return misc_register(&qos->pm_qos_power_miscdev);
}

static int find_pm_qos_object_by_minor(int minor)
{
	int pm_qos_class;

	for (pm_qos_class = 0;
		pm_qos_class < PM_QOS_NUM_CLASSES; pm_qos_class++) {
		if (minor ==
			pm_qos_array[pm_qos_class]->pm_qos_power_miscdev.minor)
			return pm_qos_class;
	}
	return -1;
}

/**
 * pm_qos_requirement - returns current system wide qos expectation
 * @pm_qos_class: identification of which qos value is requested
 *
 * This function returns the current target value in an atomic manner.
 */
int pm_qos_requirement(int pm_qos_class)
{
	int ret_val;
	unsigned long flags;

	spin_lock_irqsave(&pm_qos_lock, flags);
	ret_val = pm_qos_array[pm_qos_class]->target_value;
	spin_unlock_irqrestore(&pm_qos_lock, flags);

	return ret_val;
}
EXPORT_SYMBOL_GPL(pm_qos_requirement);

/**
 * pm_qos_add_requirement - inserts new qos request into the list
 * @pm_qos_class: identifies which list of qos request to us
 * @name: identifies the request
 * @value: defines the qos request
 *
 * This function inserts a new entry in the pm_qos_class list of requested qos
 * performance characteristics.  It recomputes the aggregate QoS expectations
 * for the pm_qos_class of parameters.
 */
int pm_qos_add_requirement(int pm_qos_class, char *name, s32 value)
{
	struct requirement_list *dep;
	unsigned long flags;

	dep = kzalloc(sizeof(struct requirement_list), GFP_KERNEL);
	if (dep) {
		if (value == PM_QOS_DEFAULT_VALUE)
			dep->value = pm_qos_array[pm_qos_class]->default_value;
		else
			dep->value = value;
		dep->name = kstrdup(name, GFP_KERNEL);
		if (!dep->name)
			goto cleanup;

		spin_lock_irqsave(&pm_qos_lock, flags);
		list_add(&dep->list,
			&pm_qos_array[pm_qos_class]->requirements.list);
		spin_unlock_irqrestore(&pm_qos_lock, flags);
		update_target(pm_qos_class);

		return 0;
	}

cleanup:
	kfree(dep);
	return -ENOMEM;
}
EXPORT_SYMBOL_GPL(pm_qos_add_requirement);

/**
 * pm_qos_update_requirement - modifies an existing qos request
 * @pm_qos_class: identifies which list of qos request to us
 * @name: identifies the request
 * @value: defines the qos request
 *
 * Updates an existing qos requirement for the pm_qos_class of parameters along
 * with updating the target pm_qos_class value.
 *
 * If the named request isn't in the list then no change is made.
 */
int pm_qos_update_requirement(int pm_qos_class, char *name, s32 new_value)
{
	unsigned long flags;
	struct requirement_list *node;
	int pending_update = 0;

	spin_lock_irqsave(&pm_qos_lock, flags);
	list_for_each_entry(node,
		&pm_qos_array[pm_qos_class]->requirements.list, list) {
		if (strcmp(node->name, name) == 0) {
			if (new_value == PM_QOS_DEFAULT_VALUE)
				node->value =
				pm_qos_array[pm_qos_class]->default_value;
			else
				node->value = new_value;
			pending_update = 1;
			break;
		}
	}
	spin_unlock_irqrestore(&pm_qos_lock, flags);
	if (pending_update)
		update_target(pm_qos_class);

	return 0;
}
EXPORT_SYMBOL_GPL(pm_qos_update_requirement);

/**
 * pm_qos_remove_requirement - modifies an existing qos request
 * @pm_qos_class: identifies which list of qos request to us
 * @name: identifies the request
 *
 * Will remove named qos request from pm_qos_class list of parameters and
 * recompute the current target value for the pm_qos_class.
 */
void pm_qos_remove_requirement(int pm_qos_class, char *name)
{
	unsigned long flags;
	struct requirement_list *node;
	int pending_update = 0;

	spin_lock_irqsave(&pm_qos_lock, flags);
	list_for_each_entry(node,
		&pm_qos_array[pm_qos_class]->requirements.list, list) {
		if (strcmp(node->name, name) == 0) {
			kfree(node->name);
			list_del(&node->list);
			kfree(node);
			pending_update = 1;
			break;
		}
	}
	spin_unlock_irqrestore(&pm_qos_lock, flags);
	if (pending_update)
		update_target(pm_qos_class);
}
EXPORT_SYMBOL_GPL(pm_qos_remove_requirement);

/**
 * pm_qos_add_notifier - sets notification entry for changes to target value
 * @pm_qos_class: identifies which qos target changes should be notified.
 * @notifier: notifier block managed by caller.
 *
 * will register the notifier into a notification chain that gets called
 * upon changes to the pm_qos_class target value.
 */
 int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
{
	int retval;

	retval = blocking_notifier_chain_register(
			pm_qos_array[pm_qos_class]->notifiers, notifier);

	return retval;
}
EXPORT_SYMBOL_GPL(pm_qos_add_notifier);

/**
 * pm_qos_remove_notifier - deletes notification entry from chain.
 * @pm_qos_class: identifies which qos target changes are notified.
 * @notifier: notifier block to be removed.
 *
 * will remove the notifier from the notification chain that gets called
 * upon changes to the pm_qos_class target value.
 */
int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
{
	int retval;

	retval = blocking_notifier_chain_unregister(
			pm_qos_array[pm_qos_class]->notifiers, notifier);

	return retval;
}
EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);

#define PID_NAME_LEN sizeof("process_1234567890")
static char name[PID_NAME_LEN];

static int pm_qos_power_open(struct inode *inode, struct file *filp)
{
	int ret;
	long pm_qos_class;

	lock_kernel();
	pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
	if (pm_qos_class >= 0) {
		filp->private_data = (void *)pm_qos_class;
		sprintf(name, "process_%d", current->pid);
		ret = pm_qos_add_requirement(pm_qos_class, name,
					PM_QOS_DEFAULT_VALUE);
		if (ret >= 0) {
			unlock_kernel();
			return 0;
		}
	}
	unlock_kernel();

	return -EPERM;
}

static int pm_qos_power_release(struct inode *inode, struct file *filp)
{
	int pm_qos_class;

	pm_qos_class = (long)filp->private_data;
	sprintf(name, "process_%d", current->pid);
	pm_qos_remove_requirement(pm_qos_class, name);

	return 0;
}

static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
		size_t count, loff_t *f_pos)
{
	s32 value;
	int pm_qos_class;

	pm_qos_class = (long)filp->private_data;
	if (count != sizeof(s32))
		return -EINVAL;
	if (copy_from_user(&value, buf, sizeof(s32)))
		return -EFAULT;
	sprintf(name, "process_%d", current->pid);
	pm_qos_update_requirement(pm_qos_class, name, value);

	return  sizeof(s32);
}


static int __init pm_qos_power_init(void)
{
	int ret = 0;

	ret = register_pm_qos_misc(&cpu_dma_pm_qos);
	if (ret < 0) {
		printk(KERN_ERR "pm_qos_param: cpu_dma_latency setup failed\n");
		return ret;
	}
	ret = register_pm_qos_misc(&network_lat_pm_qos);
	if (ret < 0) {
		printk(KERN_ERR "pm_qos_param: network_latency setup failed\n");
		return ret;
	}
	ret = register_pm_qos_misc(&network_throughput_pm_qos);
	if (ret < 0)
		printk(KERN_ERR
			"pm_qos_param: network_throughput setup failed\n");

	return ret;
}

late_initcall(pm_qos_power_init);
Commit	Line	Data
d82b3518 MG	1	/*
	2	* This module exposes the interface to kernel space for specifying
	3	* QoS dependencies. It provides infrastructure for registration of:
	4	*
	5	* Dependents on a QoS value : register requirements
	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	*
	17	* There are lists of pm_qos_objects each one wrapping requirements, notifiers
	18	*
	19	* User mode requirements 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	* requirement is removed and a new qos target is computed. This way when the
	24	* requirement 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.
	26	*
bf1db69f	27	* Mark Gross <mgross@linux.intel.com>
d82b3518 MG	28	*/
	29
	30	#include <linux/pm_qos_params.h>
	31	#include <linux/sched.h>
db26e64d	32	#include <linux/smp_lock.h>
d82b3518 MG	33	#include <linux/spinlock.h>
	34	#include <linux/slab.h>
	35	#include <linux/time.h>
	36	#include <linux/fs.h>
	37	#include <linux/device.h>
	38	#include <linux/miscdevice.h>
	39	#include <linux/string.h>
	40	#include <linux/platform_device.h>
	41	#include <linux/init.h>
	42
	43	#include <linux/uaccess.h>
	44
	45	/*
	46	* locking rule: all changes to target_value or requirements or notifiers lists
	47	* or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
	48	* held, taken with _irqsave. One lock to rule them all
	49	*/
	50	struct requirement_list {
	51	struct list_head list;
	52	union {
	53	s32 value;
	54	s32 usec;
	55	s32 kbps;
	56	};
	57	char *name;
	58	};
	59
	60	static s32 max_compare(s32 v1, s32 v2);
	61	static s32 min_compare(s32 v1, s32 v2);
	62
	63	struct pm_qos_object {
	64	struct requirement_list requirements;
	65	struct blocking_notifier_head *notifiers;
	66	struct miscdevice pm_qos_power_miscdev;
	67	char *name;
	68	s32 default_value;
	69	s32 target_value;
	70	s32 (*comparitor)(s32, s32);
	71	};
	72
	73	static struct pm_qos_object null_pm_qos;
	74	static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
	75	static struct pm_qos_object cpu_dma_pm_qos = {
	76	.requirements = {LIST_HEAD_INIT(cpu_dma_pm_qos.requirements.list)},
	77	.notifiers = &cpu_dma_lat_notifier,
	78	.name = "cpu_dma_latency",
	79	.default_value = 2000 * USEC_PER_SEC,
	80	.target_value = 2000 * USEC_PER_SEC,
	81	.comparitor = min_compare
	82	};
	83
	84	static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
	85	static struct pm_qos_object network_lat_pm_qos = {
	86	.requirements = {LIST_HEAD_INIT(network_lat_pm_qos.requirements.list)},
	87	.notifiers = &network_lat_notifier,
	88	.name = "network_latency",
	89	.default_value = 2000 * USEC_PER_SEC,
	90	.target_value = 2000 * USEC_PER_SEC,
	91	.comparitor = min_compare
	92	};
	93
	94
	95	static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
	96	static struct pm_qos_object network_throughput_pm_qos = {
97	.requirements =
98	{LIST_HEAD_INIT(network_throughput_pm_qos.requirements.list)},
99	.notifiers = &network_throughput_notifier,
100	.name = "network_throughput",
101	.default_value = 0,
102	.target_value = 0,
103	.comparitor = max_compare
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
114	static DEFINE_SPINLOCK(pm_qos_lock);
115
116	static ssize_t pm_qos_power_write(struct file filp, const char __user buf,
117	size_t count, loff_t *f_pos);
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,
123	.open = pm_qos_power_open,
124	.release = pm_qos_power_release,
125	};
126
127	/* static helper functions */
128	static s32 max_compare(s32 v1, s32 v2)
129	{
130	return max(v1, v2);
131	}
132
133	static s32 min_compare(s32 v1, s32 v2)
134	{
135	return min(v1, v2);
136	}
137
138
139	static void update_target(int target)
140	{
141	s32 extreme_value;
142	struct requirement_list *node;
143	unsigned long flags;
144	int call_notifier = 0;
145
146	spin_lock_irqsave(&pm_qos_lock, flags);
147	extreme_value = pm_qos_array[target]->default_value;
148	list_for_each_entry(node,
149	&pm_qos_array[target]->requirements.list, list) {
150	extreme_value = pm_qos_array[target]->comparitor(
151	extreme_value, node->value);
152	}
153	if (pm_qos_array[target]->target_value != extreme_value) {
154	call_notifier = 1;
155	pm_qos_array[target]->target_value = extreme_value;
156	pr_debug(KERN_ERR "new target for qos %d is %d\n", target,
157	pm_qos_array[target]->target_value);
158	}
159	spin_unlock_irqrestore(&pm_qos_lock, flags);
160
161	if (call_notifier)
162	blocking_notifier_call_chain(pm_qos_array[target]->notifiers,
163	(unsigned long) extreme_value, NULL);
164	}
165
166	static int register_pm_qos_misc(struct pm_qos_object *qos)
167	{
168	qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR;
169	qos->pm_qos_power_miscdev.name = qos->name;
170	qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops;
171
172	return misc_register(&qos->pm_qos_power_miscdev);
173	}
174
175	static int find_pm_qos_object_by_minor(int minor)
176	{
177	int pm_qos_class;
178
179	for (pm_qos_class = 0;
180	pm_qos_class < PM_QOS_NUM_CLASSES; pm_qos_class++) {
181	if (minor ==
182	pm_qos_array[pm_qos_class]->pm_qos_power_miscdev.minor)
183	return pm_qos_class;
184	}
185	return -1;
186	}
187
188	/**
189	* pm_qos_requirement - returns current system wide qos expectation
190	* @pm_qos_class: identification of which qos value is requested
191	*
192	* This function returns the current target value in an atomic manner.
193	*/
194	int pm_qos_requirement(int pm_qos_class)
195	{
196	int ret_val;
197	unsigned long flags;
198
199	spin_lock_irqsave(&pm_qos_lock, flags);
200	ret_val = pm_qos_array[pm_qos_class]->target_value;
201	spin_unlock_irqrestore(&pm_qos_lock, flags);
202
203	return ret_val;
204	}
205	EXPORT_SYMBOL_GPL(pm_qos_requirement);
206
207	/**
208	* pm_qos_add_requirement - inserts new qos request into the list
209	* @pm_qos_class: identifies which list of qos request to us
210	* @name: identifies the request
211	* @value: defines the qos request
212	*
213	* This function inserts a new entry in the pm_qos_class list of requested qos
bf1db69f RH	214	* performance characteristics. It recomputes the aggregate QoS expectations
bf1db69f RH	215	* for the pm_qos_class of parameters.
d82b3518 MG	216	*/
	217	int pm_qos_add_requirement(int pm_qos_class, char *name, s32 value)
	218	{
	219	struct requirement_list *dep;
	220	unsigned long flags;
	221
	222	dep = kzalloc(sizeof(struct requirement_list), GFP_KERNEL);
	223	if (dep) {
	224	if (value == PM_QOS_DEFAULT_VALUE)
	225	dep->value = pm_qos_array[pm_qos_class]->default_value;
	226	else
	227	dep->value = value;
	228	dep->name = kstrdup(name, GFP_KERNEL);
	229	if (!dep->name)
	230	goto cleanup;
	231
	232	spin_lock_irqsave(&pm_qos_lock, flags);
	233	list_add(&dep->list,
	234	&pm_qos_array[pm_qos_class]->requirements.list);
	235	spin_unlock_irqrestore(&pm_qos_lock, flags);
	236	update_target(pm_qos_class);
	237
	238	return 0;
	239	}
	240
	241	cleanup:
	242	kfree(dep);
	243	return -ENOMEM;
	244	}
	245	EXPORT_SYMBOL_GPL(pm_qos_add_requirement);
	246
	247	/**
	248	* pm_qos_update_requirement - modifies an existing qos request
	249	* @pm_qos_class: identifies which list of qos request to us
	250	* @name: identifies the request
	251	* @value: defines the qos request
	252	*
bf1db69f	253	* Updates an existing qos requirement for the pm_qos_class of parameters along
d82b3518 MG	254	* with updating the target pm_qos_class value.
d82b3518 MG	255	*
bf1db69f	256	* If the named request isn't in the list then no change is made.
d82b3518 MG	257	*/
	258	int pm_qos_update_requirement(int pm_qos_class, char *name, s32 new_value)
	259	{
	260	unsigned long flags;
	261	struct requirement_list *node;
	262	int pending_update = 0;
	263
	264	spin_lock_irqsave(&pm_qos_lock, flags);
	265	list_for_each_entry(node,
	266	&pm_qos_array[pm_qos_class]->requirements.list, list) {
	267	if (strcmp(node->name, name) == 0) {
	268	if (new_value == PM_QOS_DEFAULT_VALUE)
	269	node->value =
	270	pm_qos_array[pm_qos_class]->default_value;
	271	else
	272	node->value = new_value;
	273	pending_update = 1;
	274	break;
	275	}
	276	}
	277	spin_unlock_irqrestore(&pm_qos_lock, flags);
	278	if (pending_update)
	279	update_target(pm_qos_class);
	280
	281	return 0;
	282	}
	283	EXPORT_SYMBOL_GPL(pm_qos_update_requirement);
	284
	285	/**
	286	* pm_qos_remove_requirement - modifies an existing qos request
	287	* @pm_qos_class: identifies which list of qos request to us
	288	* @name: identifies the request
	289	*
bf1db69f	290	* Will remove named qos request from pm_qos_class list of parameters and
d82b3518 MG	291	* recompute the current target value for the pm_qos_class.
	292	*/
	293	void pm_qos_remove_requirement(int pm_qos_class, char *name)
	294	{
	295	unsigned long flags;
	296	struct requirement_list *node;
	297	int pending_update = 0;
	298
	299	spin_lock_irqsave(&pm_qos_lock, flags);
	300	list_for_each_entry(node,
	301	&pm_qos_array[pm_qos_class]->requirements.list, list) {
	302	if (strcmp(node->name, name) == 0) {
	303	kfree(node->name);
	304	list_del(&node->list);
	305	kfree(node);
	306	pending_update = 1;
	307	break;
	308	}
	309	}
	310	spin_unlock_irqrestore(&pm_qos_lock, flags);
	311	if (pending_update)
	312	update_target(pm_qos_class);
	313	}
	314	EXPORT_SYMBOL_GPL(pm_qos_remove_requirement);
	315
	316	/**
	317	* pm_qos_add_notifier - sets notification entry for changes to target value
	318	* @pm_qos_class: identifies which qos target changes should be notified.
	319	* @notifier: notifier block managed by caller.
	320	*
	321	* will register the notifier into a notification chain that gets called
bf1db69f	322	* upon changes to the pm_qos_class target value.
d82b3518 MG	323	*/
	324	int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
	325	{
	326	int retval;
	327
	328	retval = blocking_notifier_chain_register(
	329	pm_qos_array[pm_qos_class]->notifiers, notifier);
	330
	331	return retval;
	332	}
	333	EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
	334
	335	/**
	336	* pm_qos_remove_notifier - deletes notification entry from chain.
	337	* @pm_qos_class: identifies which qos target changes are notified.
	338	* @notifier: notifier block to be removed.
	339	*
	340	* will remove the notifier from the notification chain that gets called
bf1db69f	341	* upon changes to the pm_qos_class target value.
d82b3518 MG	342	*/
	343	int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
	344	{
	345	int retval;
	346
	347	retval = blocking_notifier_chain_unregister(
	348	pm_qos_array[pm_qos_class]->notifiers, notifier);
	349
	350	return retval;
	351	}
	352	EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
	353
	354	#define PID_NAME_LEN sizeof("process_1234567890")
	355	static char name[PID_NAME_LEN];
	356
	357	static int pm_qos_power_open(struct inode inode, struct file filp)
	358	{
	359	int ret;
	360	long pm_qos_class;
	361
db26e64d	362	lock_kernel();
d82b3518 MG	363	pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
	364	if (pm_qos_class >= 0) {
	365	filp->private_data = (void *)pm_qos_class;
	366	sprintf(name, "process_%d", current->pid);
	367	ret = pm_qos_add_requirement(pm_qos_class, name,
	368	PM_QOS_DEFAULT_VALUE);
db26e64d AB	369	if (ret >= 0) {
db26e64d AB	370	unlock_kernel();
d82b3518	371	return 0;
db26e64d	372	}
d82b3518	373	}
db26e64d	374	unlock_kernel();
d82b3518 MG	375
	376	return -EPERM;
	377	}
	378
	379	static int pm_qos_power_release(struct inode inode, struct file filp)
	380	{
	381	int pm_qos_class;
	382
	383	pm_qos_class = (long)filp->private_data;
	384	sprintf(name, "process_%d", current->pid);
	385	pm_qos_remove_requirement(pm_qos_class, name);
	386
	387	return 0;
	388	}
	389
	390	static ssize_t pm_qos_power_write(struct file filp, const char __user buf,
	391	size_t count, loff_t *f_pos)
	392	{
	393	s32 value;
	394	int pm_qos_class;
	395
	396	pm_qos_class = (long)filp->private_data;
	397	if (count != sizeof(s32))
	398	return -EINVAL;
	399	if (copy_from_user(&value, buf, sizeof(s32)))
	400	return -EFAULT;
	401	sprintf(name, "process_%d", current->pid);
	402	pm_qos_update_requirement(pm_qos_class, name, value);
	403
	404	return sizeof(s32);
	405	}
	406
	407
	408	static int __init pm_qos_power_init(void)
	409	{
	410	int ret = 0;
	411
	412	ret = register_pm_qos_misc(&cpu_dma_pm_qos);
	413	if (ret < 0) {
	414	printk(KERN_ERR "pm_qos_param: cpu_dma_latency setup failed\n");
	415	return ret;
	416	}
	417	ret = register_pm_qos_misc(&network_lat_pm_qos);
	418	if (ret < 0) {
	419	printk(KERN_ERR "pm_qos_param: network_latency setup failed\n");
	420	return ret;
	421	}
	422	ret = register_pm_qos_misc(&network_throughput_pm_qos);
	423	if (ret < 0)
	424	printk(KERN_ERR
	425	"pm_qos_param: network_throughput setup failed\n");
	426
	427	return ret;
	428	}
	429
	430	late_initcall(pm_qos_power_init);