[linux-2.6-block.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/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 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;
	atomic_t 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 = ATOMIC_INIT(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 = ATOMIC_INIT(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 = ATOMIC_INIT(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 (atomic_read(&pm_qos_array[target]->target_value) != extreme_value) {
		call_notifier = 1;
		atomic_set(&pm_qos_array[target]->target_value, extreme_value);
		pr_debug(KERN_ERR "new target for qos %d is %d\n", target,
			atomic_read(&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)
{
	return atomic_read(&pm_qos_array[pm_qos_class]->target_value);
}
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 32

static int pm_qos_power_open(struct inode *inode, struct file *filp)
{
	int ret;
	long pm_qos_class;
	char name[PID_NAME_LEN];

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

static int pm_qos_power_release(struct inode *inode, struct file *filp)
{
	int pm_qos_class;
	char name[PID_NAME_LEN];

	pm_qos_class = (long)filp->private_data;
	snprintf(name, PID_NAME_LEN, "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;
	char name[PID_NAME_LEN];

	pm_qos_class = (long)filp->private_data;
	if (count != sizeof(s32))
		return -EINVAL;
	if (copy_from_user(&value, buf, sizeof(s32)))
		return -EFAULT;
	snprintf(name, PID_NAME_LEN, "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>
	32	#include <linux/spinlock.h>
	33	#include <linux/slab.h>
	34	#include <linux/time.h>
	35	#include <linux/fs.h>
	36	#include <linux/device.h>
	37	#include <linux/miscdevice.h>
	38	#include <linux/string.h>
	39	#include <linux/platform_device.h>
	40	#include <linux/init.h>
	41
	42	#include <linux/uaccess.h>
	43
	44	/*
9d359357	45	* locking rule: all changes to requirements or notifiers lists
d82b3518 MG	46	* or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
	47	* held, taken with _irqsave. One lock to rule them all
	48	*/
	49	struct requirement_list {
	50	struct list_head list;
	51	union {
	52	s32 value;
	53	s32 usec;
	54	s32 kbps;
	55	};
	56	char *name;
	57	};
	58
	59	static s32 max_compare(s32 v1, s32 v2);
	60	static s32 min_compare(s32 v1, s32 v2);
	61
	62	struct pm_qos_object {
	63	struct requirement_list requirements;
	64	struct blocking_notifier_head *notifiers;
	65	struct miscdevice pm_qos_power_miscdev;
	66	char *name;
	67	s32 default_value;
9d359357	68	atomic_t target_value;
d82b3518 MG	69	s32 (*comparitor)(s32, s32);
	70	};
	71
	72	static struct pm_qos_object null_pm_qos;
	73	static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
	74	static struct pm_qos_object cpu_dma_pm_qos = {
	75	.requirements = {LIST_HEAD_INIT(cpu_dma_pm_qos.requirements.list)},
	76	.notifiers = &cpu_dma_lat_notifier,
	77	.name = "cpu_dma_latency",
	78	.default_value = 2000 * USEC_PER_SEC,
9d359357	79	.target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
d82b3518 MG	80	.comparitor = min_compare
	81	};
	82
	83	static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
	84	static struct pm_qos_object network_lat_pm_qos = {
	85	.requirements = {LIST_HEAD_INIT(network_lat_pm_qos.requirements.list)},
	86	.notifiers = &network_lat_notifier,
	87	.name = "network_latency",
	88	.default_value = 2000 * USEC_PER_SEC,
9d359357	89	.target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
d82b3518 MG	90	.comparitor = min_compare
	91	};
	92
	93
	94	static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
	95	static struct pm_qos_object network_throughput_pm_qos = {
	96	.requirements =
	97	{LIST_HEAD_INIT(network_throughput_pm_qos.requirements.list)},
	98	.notifiers = &network_throughput_notifier,
	99	.name = "network_throughput",
	100	.default_value = 0,
9d359357	101	.target_value = ATOMIC_INIT(0),
d82b3518 MG	102	.comparitor = max_compare
	103	};
	104
	105
	106	static struct pm_qos_object *pm_qos_array[] = {
	107	&null_pm_qos,
	108	&cpu_dma_pm_qos,
	109	&network_lat_pm_qos,
	110	&network_throughput_pm_qos
	111	};
	112
	113	static DEFINE_SPINLOCK(pm_qos_lock);
	114
	115	static ssize_t pm_qos_power_write(struct file filp, const char __user buf,
	116	size_t count, loff_t *f_pos);
	117	static int pm_qos_power_open(struct inode inode, struct file filp);
	118	static int pm_qos_power_release(struct inode inode, struct file filp);
	119
	120	static const struct file_operations pm_qos_power_fops = {
	121	.write = pm_qos_power_write,
	122	.open = pm_qos_power_open,
	123	.release = pm_qos_power_release,
	124	};
	125
	126	/* static helper functions */
	127	static s32 max_compare(s32 v1, s32 v2)
	128	{
	129	return max(v1, v2);
	130	}
	131
	132	static s32 min_compare(s32 v1, s32 v2)
	133	{
	134	return min(v1, v2);
	135	}
	136
	137
	138	static void update_target(int target)
	139	{
	140	s32 extreme_value;
	141	struct requirement_list *node;
	142	unsigned long flags;
	143	int call_notifier = 0;
	144
	145	spin_lock_irqsave(&pm_qos_lock, flags);
	146	extreme_value = pm_qos_array[target]->default_value;
	147	list_for_each_entry(node,
	148	&pm_qos_array[target]->requirements.list, list) {
	149	extreme_value = pm_qos_array[target]->comparitor(
	150	extreme_value, node->value);
	151	}
9d359357	152	if (atomic_read(&pm_qos_array[target]->target_value) != extreme_value) {
d82b3518	153	call_notifier = 1;
9d359357	154	atomic_set(&pm_qos_array[target]->target_value, extreme_value);
d82b3518	155	pr_debug(KERN_ERR "new target for qos %d is %d\n", target,
9d359357	156	atomic_read(&pm_qos_array[target]->target_value));
d82b3518 MG	157	}
	158	spin_unlock_irqrestore(&pm_qos_lock, flags);
	159
	160	if (call_notifier)
	161	blocking_notifier_call_chain(pm_qos_array[target]->notifiers,
	162	(unsigned long) extreme_value, NULL);
	163	}
	164
	165	static int register_pm_qos_misc(struct pm_qos_object *qos)
	166	{
	167	qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR;
	168	qos->pm_qos_power_miscdev.name = qos->name;
	169	qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops;
	170
	171	return misc_register(&qos->pm_qos_power_miscdev);
	172	}
	173
	174	static int find_pm_qos_object_by_minor(int minor)
	175	{
	176	int pm_qos_class;
	177
	178	for (pm_qos_class = 0;
	179	pm_qos_class < PM_QOS_NUM_CLASSES; pm_qos_class++) {
	180	if (minor ==
	181	pm_qos_array[pm_qos_class]->pm_qos_power_miscdev.minor)
	182	return pm_qos_class;
	183	}
	184	return -1;
	185	}
	186
	187	/**
	188	* pm_qos_requirement - returns current system wide qos expectation
	189	* @pm_qos_class: identification of which qos value is requested
	190	*
	191	* This function returns the current target value in an atomic manner.
	192	*/
	193	int pm_qos_requirement(int pm_qos_class)
	194	{
9d359357	195	return atomic_read(&pm_qos_array[pm_qos_class]->target_value);
d82b3518 MG	196	}
	197	EXPORT_SYMBOL_GPL(pm_qos_requirement);
	198
	199	/**
	200	* pm_qos_add_requirement - inserts new qos request into the list
	201	* @pm_qos_class: identifies which list of qos request to us
	202	* @name: identifies the request
	203	* @value: defines the qos request
	204	*
	205	* This function inserts a new entry in the pm_qos_class list of requested qos
bf1db69f RH	206	* performance characteristics. It recomputes the aggregate QoS expectations
bf1db69f RH	207	* for the pm_qos_class of parameters.
d82b3518 MG	208	*/
	209	int pm_qos_add_requirement(int pm_qos_class, char *name, s32 value)
	210	{
	211	struct requirement_list *dep;
	212	unsigned long flags;
	213
	214	dep = kzalloc(sizeof(struct requirement_list), GFP_KERNEL);
	215	if (dep) {
	216	if (value == PM_QOS_DEFAULT_VALUE)
	217	dep->value = pm_qos_array[pm_qos_class]->default_value;
	218	else
	219	dep->value = value;
	220	dep->name = kstrdup(name, GFP_KERNEL);
	221	if (!dep->name)
	222	goto cleanup;
	223
	224	spin_lock_irqsave(&pm_qos_lock, flags);
	225	list_add(&dep->list,
	226	&pm_qos_array[pm_qos_class]->requirements.list);
	227	spin_unlock_irqrestore(&pm_qos_lock, flags);
	228	update_target(pm_qos_class);
	229
	230	return 0;
	231	}
	232
	233	cleanup:
	234	kfree(dep);
	235	return -ENOMEM;
	236	}
	237	EXPORT_SYMBOL_GPL(pm_qos_add_requirement);
	238
	239	/**
	240	* pm_qos_update_requirement - modifies an existing qos request
	241	* @pm_qos_class: identifies which list of qos request to us
	242	* @name: identifies the request
	243	* @value: defines the qos request
	244	*
bf1db69f	245	* Updates an existing qos requirement for the pm_qos_class of parameters along
d82b3518 MG	246	* with updating the target pm_qos_class value.
d82b3518 MG	247	*
bf1db69f	248	* If the named request isn't in the list then no change is made.
d82b3518 MG	249	*/
	250	int pm_qos_update_requirement(int pm_qos_class, char *name, s32 new_value)
	251	{
	252	unsigned long flags;
	253	struct requirement_list *node;
	254	int pending_update = 0;
	255
	256	spin_lock_irqsave(&pm_qos_lock, flags);
	257	list_for_each_entry(node,
	258	&pm_qos_array[pm_qos_class]->requirements.list, list) {
	259	if (strcmp(node->name, name) == 0) {
	260	if (new_value == PM_QOS_DEFAULT_VALUE)
	261	node->value =
	262	pm_qos_array[pm_qos_class]->default_value;
	263	else
	264	node->value = new_value;
	265	pending_update = 1;
	266	break;
	267	}
	268	}
	269	spin_unlock_irqrestore(&pm_qos_lock, flags);
	270	if (pending_update)
	271	update_target(pm_qos_class);
	272
	273	return 0;
	274	}
	275	EXPORT_SYMBOL_GPL(pm_qos_update_requirement);
	276
	277	/**
	278	* pm_qos_remove_requirement - modifies an existing qos request
	279	* @pm_qos_class: identifies which list of qos request to us
	280	* @name: identifies the request
	281	*
bf1db69f	282	* Will remove named qos request from pm_qos_class list of parameters and
d82b3518 MG	283	* recompute the current target value for the pm_qos_class.
	284	*/
	285	void pm_qos_remove_requirement(int pm_qos_class, char *name)
	286	{
	287	unsigned long flags;
	288	struct requirement_list *node;
	289	int pending_update = 0;
	290
	291	spin_lock_irqsave(&pm_qos_lock, flags);
	292	list_for_each_entry(node,
	293	&pm_qos_array[pm_qos_class]->requirements.list, list) {
	294	if (strcmp(node->name, name) == 0) {
	295	kfree(node->name);
	296	list_del(&node->list);
	297	kfree(node);
	298	pending_update = 1;
	299	break;
	300	}
	301	}
	302	spin_unlock_irqrestore(&pm_qos_lock, flags);
	303	if (pending_update)
	304	update_target(pm_qos_class);
	305	}
	306	EXPORT_SYMBOL_GPL(pm_qos_remove_requirement);
	307
	308	/**
	309	* pm_qos_add_notifier - sets notification entry for changes to target value
	310	* @pm_qos_class: identifies which qos target changes should be notified.
	311	* @notifier: notifier block managed by caller.
	312	*
	313	* will register the notifier into a notification chain that gets called
bf1db69f	314	* upon changes to the pm_qos_class target value.
d82b3518 MG	315	*/
	316	int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
	317	{
	318	int retval;
	319
	320	retval = blocking_notifier_chain_register(
	321	pm_qos_array[pm_qos_class]->notifiers, notifier);
	322
	323	return retval;
	324	}
	325	EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
	326
	327	/**
	328	* pm_qos_remove_notifier - deletes notification entry from chain.
	329	* @pm_qos_class: identifies which qos target changes are notified.
	330	* @notifier: notifier block to be removed.
	331	*
	332	* will remove the notifier from the notification chain that gets called
bf1db69f	333	* upon changes to the pm_qos_class target value.
d82b3518 MG	334	*/
	335	int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
	336	{
	337	int retval;
	338
	339	retval = blocking_notifier_chain_unregister(
	340	pm_qos_array[pm_qos_class]->notifiers, notifier);
	341
	342	return retval;
	343	}
	344	EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
	345
1a6deaea	346	#define PID_NAME_LEN 32
d82b3518 MG	347
	348	static int pm_qos_power_open(struct inode inode, struct file filp)
	349	{
	350	int ret;
	351	long pm_qos_class;
1a6deaea	352	char name[PID_NAME_LEN];
d82b3518 MG	353
	354	pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
	355	if (pm_qos_class >= 0) {
	356	filp->private_data = (void *)pm_qos_class;
1a6deaea	357	snprintf(name, PID_NAME_LEN, "process_%d", current->pid);
d82b3518 MG	358	ret = pm_qos_add_requirement(pm_qos_class, name,
d82b3518 MG	359	PM_QOS_DEFAULT_VALUE);
e6fe07a0	360	if (ret >= 0)
d82b3518 MG	361	return 0;
d82b3518 MG	362	}
d82b3518 MG	363	return -EPERM;
	364	}
	365
	366	static int pm_qos_power_release(struct inode inode, struct file filp)
	367	{
	368	int pm_qos_class;
1a6deaea	369	char name[PID_NAME_LEN];
d82b3518 MG	370
d82b3518 MG	371	pm_qos_class = (long)filp->private_data;
1a6deaea	372	snprintf(name, PID_NAME_LEN, "process_%d", current->pid);
d82b3518 MG	373	pm_qos_remove_requirement(pm_qos_class, name);
	374
	375	return 0;
	376	}
	377
	378	static ssize_t pm_qos_power_write(struct file filp, const char __user buf,
	379	size_t count, loff_t *f_pos)
	380	{
	381	s32 value;
	382	int pm_qos_class;
1a6deaea	383	char name[PID_NAME_LEN];
d82b3518 MG	384
	385	pm_qos_class = (long)filp->private_data;
	386	if (count != sizeof(s32))
	387	return -EINVAL;
	388	if (copy_from_user(&value, buf, sizeof(s32)))
	389	return -EFAULT;
1a6deaea	390	snprintf(name, PID_NAME_LEN, "process_%d", current->pid);
d82b3518 MG	391	pm_qos_update_requirement(pm_qos_class, name, value);
	392
	393	return sizeof(s32);
	394	}
	395
	396
	397	static int __init pm_qos_power_init(void)
	398	{
	399	int ret = 0;
	400
	401	ret = register_pm_qos_misc(&cpu_dma_pm_qos);
	402	if (ret < 0) {
	403	printk(KERN_ERR "pm_qos_param: cpu_dma_latency setup failed\n");
	404	return ret;
	405	}
	406	ret = register_pm_qos_misc(&network_lat_pm_qos);
	407	if (ret < 0) {
	408	printk(KERN_ERR "pm_qos_param: network_latency setup failed\n");
	409	return ret;
	410	}
	411	ret = register_pm_qos_misc(&network_throughput_pm_qos);
	412	if (ret < 0)
	413	printk(KERN_ERR
	414	"pm_qos_param: network_throughput setup failed\n");
	415
	416	return ret;
	417	}
	418
	419	late_initcall(pm_qos_power_init);