[net-next-2.6.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 requests
 * 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 requests, notifiers
 *
 * User mode requests 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
 * request is removed and a new qos target is computed.  This way when the
 * request 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>
 */

/*#define DEBUG*/

#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 requests 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
 */
enum pm_qos_type {
	PM_QOS_MAX,		/* return the largest value */
	PM_QOS_MIN		/* return the smallest value */
};

struct pm_qos_object {
	struct plist_head requests;
	struct blocking_notifier_head *notifiers;
	struct miscdevice pm_qos_power_miscdev;
	char *name;
	s32 default_value;
	enum pm_qos_type type;
};

static DEFINE_SPINLOCK(pm_qos_lock);

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 = {
	.requests = PLIST_HEAD_INIT(cpu_dma_pm_qos.requests, pm_qos_lock),
	.notifiers = &cpu_dma_lat_notifier,
	.name = "cpu_dma_latency",
	.default_value = 2000 * USEC_PER_SEC,
	.type = PM_QOS_MIN,
};

static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
static struct pm_qos_object network_lat_pm_qos = {
	.requests = PLIST_HEAD_INIT(network_lat_pm_qos.requests, pm_qos_lock),
	.notifiers = &network_lat_notifier,
	.name = "network_latency",
	.default_value = 2000 * USEC_PER_SEC,
	.type = PM_QOS_MIN
};


static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
static struct pm_qos_object network_throughput_pm_qos = {
	.requests = PLIST_HEAD_INIT(network_throughput_pm_qos.requests, pm_qos_lock),
	.notifiers = &network_throughput_notifier,
	.name = "network_throughput",
	.default_value = 0,
	.type = PM_QOS_MAX,
};


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

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,
};

/* unlocked internal variant */
static inline int pm_qos_get_value(struct pm_qos_object *o)
{
	if (plist_head_empty(&o->requests))
		return o->default_value;

	switch (o->type) {
	case PM_QOS_MIN:
		return plist_last(&o->requests)->prio;

	case PM_QOS_MAX:
		return plist_first(&o->requests)->prio;

	default:
		/* runtime check for not using enum */
		BUG();
	}
}

static void update_target(struct pm_qos_object *o, struct plist_node *node,
			  int del, int value)
{
	unsigned long flags;
	int prev_value, curr_value;

	spin_lock_irqsave(&pm_qos_lock, flags);
	prev_value = pm_qos_get_value(o);
	/* PM_QOS_DEFAULT_VALUE is a signal that the value is unchanged */
	if (value != PM_QOS_DEFAULT_VALUE) {
		/*
		 * to change the list, we atomically remove, reinit
		 * with new value and add, then see if the extremal
		 * changed
		 */
		plist_del(node, &o->requests);
		plist_node_init(node, value);
		plist_add(node, &o->requests);
	} else if (del) {
		plist_del(node, &o->requests);
	} else {
		plist_add(node, &o->requests);
	}
	curr_value = pm_qos_get_value(o);
	spin_unlock_irqrestore(&pm_qos_lock, flags);

	if (prev_value != curr_value)
		blocking_notifier_call_chain(o->notifiers,
					     (unsigned long)curr_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_request - 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_request(int pm_qos_class)
{
	unsigned long flags;
	int value;

	spin_lock_irqsave(&pm_qos_lock, flags);
	value = pm_qos_get_value(pm_qos_array[pm_qos_class]);
	spin_unlock_irqrestore(&pm_qos_lock, flags);

	return value;
}
EXPORT_SYMBOL_GPL(pm_qos_request);

int pm_qos_request_active(struct pm_qos_request_list *req)
{
	return req->pm_qos_class != 0;
}
EXPORT_SYMBOL_GPL(pm_qos_request_active);

/**
 * pm_qos_add_request - inserts new qos request into the list
 * @dep: pointer to a preallocated handle
 * @pm_qos_class: identifies which list of qos request to use
 * @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 and initializes the pm_qos_request_list
 * handle.  Caller needs to save this handle for later use in updates and
 * removal.
 */

void pm_qos_add_request(struct pm_qos_request_list *dep,
			int pm_qos_class, s32 value)
{
	struct pm_qos_object *o =  pm_qos_array[pm_qos_class];
	int new_value;

	if (pm_qos_request_active(dep)) {
		WARN(1, KERN_ERR "pm_qos_add_request() called for already added request\n");
		return;
	}
	if (value == PM_QOS_DEFAULT_VALUE)
		new_value = o->default_value;
	else
		new_value = value;
	plist_node_init(&dep->list, new_value);
	dep->pm_qos_class = pm_qos_class;
	update_target(o, &dep->list, 0, PM_QOS_DEFAULT_VALUE);
}
EXPORT_SYMBOL_GPL(pm_qos_add_request);

/**
 * pm_qos_update_request - modifies an existing qos request
 * @pm_qos_req : handle to list element holding a pm_qos request to use
 * @value: defines the qos request
 *
 * Updates an existing qos request for the pm_qos_class of parameters along
 * with updating the target pm_qos_class value.
 *
 * Attempts are made to make this code callable on hot code paths.
 */
void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
			   s32 new_value)
{
	s32 temp;
	struct pm_qos_object *o;

	if (!pm_qos_req) /*guard against callers passing in null */
		return;

	if (!pm_qos_request_active(pm_qos_req)) {
		WARN(1, KERN_ERR "pm_qos_update_request() called for unknown object\n");
		return;
	}

	o = pm_qos_array[pm_qos_req->pm_qos_class];

	if (new_value == PM_QOS_DEFAULT_VALUE)
		temp = o->default_value;
	else
		temp = new_value;

	if (temp != pm_qos_req->list.prio)
		update_target(o, &pm_qos_req->list, 0, temp);
}
EXPORT_SYMBOL_GPL(pm_qos_update_request);

/**
 * pm_qos_remove_request - modifies an existing qos request
 * @pm_qos_req: handle to request list element
 *
 * Will remove pm qos request from the list of requests and
 * recompute the current target value for the pm_qos_class.  Call this
 * on slow code paths.
 */
void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req)
{
	struct pm_qos_object *o;

	if (pm_qos_req == NULL)
		return;
		/* silent return to keep pcm code cleaner */

	if (!pm_qos_request_active(pm_qos_req)) {
		WARN(1, KERN_ERR "pm_qos_remove_request() called for unknown object\n");
		return;
	}

	o = pm_qos_array[pm_qos_req->pm_qos_class];
	update_target(o, &pm_qos_req->list, 1, PM_QOS_DEFAULT_VALUE);
	memset(pm_qos_req, 0, sizeof(*pm_qos_req));
}
EXPORT_SYMBOL_GPL(pm_qos_remove_request);

/**
 * 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);

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

	pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
	if (pm_qos_class >= 0) {
               struct pm_qos_request_list *req = kzalloc(sizeof(*req), GFP_KERNEL);
		if (!req)
			return -ENOMEM;

		pm_qos_add_request(req, pm_qos_class, PM_QOS_DEFAULT_VALUE);
		filp->private_data = req;

		if (filp->private_data)
			return 0;
	}
	return -EPERM;
}

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

	req = filp->private_data;
	pm_qos_remove_request(req);
	kfree(req);

	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 x;
	char ascii_value[11];
	struct pm_qos_request_list *pm_qos_req;

	if (count == sizeof(s32)) {
		if (copy_from_user(&value, buf, sizeof(s32)))
			return -EFAULT;
	} else if (count == 11) { /* len('0x12345678/0') */
		if (copy_from_user(ascii_value, buf, 11))
			return -EFAULT;
		x = sscanf(ascii_value, "%x", &value);
		if (x != 1)
			return -EINVAL;
		pr_debug(KERN_ERR "%s, %d, 0x%x\n", ascii_value, x, value);
	} else
		return -EINVAL;

	pm_qos_req = (struct pm_qos_request_list *)filp->private_data;
	pm_qos_update_request(pm_qos_req, value);

	return count;
}


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	*
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
ed77134b MG	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.
d82b3518 MG	26	*
bf1db69f	27	* Mark Gross <mgross@linux.intel.com>
d82b3518 MG	28	*/
d82b3518 MG	29
ed77134b MG	30	/#define DEBUG/
ed77134b MG	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
d82b3518 MG	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	};
d82b3518 MG	64
5f279845 JB	65	static DEFINE_SPINLOCK(pm_qos_lock);
5f279845 JB	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,
	113	};
	114
5f279845 JB	115	/* unlocked internal variant */
5f279845 JB	116	static inline int pm_qos_get_value(struct pm_qos_object *o)
d82b3518	117	{
5f279845 JB	118	if (plist_head_empty(&o->requests))
5f279845 JB	119	return o->default_value;
d82b3518	120
5f279845 JB	121	switch (o->type) {
	122	case PM_QOS_MIN:
	123	return plist_last(&o->requests)->prio;
d82b3518	124
5f279845 JB	125	case PM_QOS_MAX:
5f279845 JB	126	return plist_first(&o->requests)->prio;
d82b3518	127
5f279845 JB	128	default:
	129	/* runtime check for not using enum */
	130	BUG();
	131	}
	132	}
	133
	134	static void update_target(struct pm_qos_object o, struct plist_node node,
	135	int del, int value)
d82b3518	136	{
d82b3518	137	unsigned long flags;
5f279845	138	int prev_value, curr_value;
d82b3518 MG	139
d82b3518 MG	140	spin_lock_irqsave(&pm_qos_lock, flags);
5f279845 JB	141	prev_value = pm_qos_get_value(o);
	142	/* PM_QOS_DEFAULT_VALUE is a signal that the value is unchanged */
	143	if (value != PM_QOS_DEFAULT_VALUE) {
	144	/*
	145	* to change the list, we atomically remove, reinit
	146	* with new value and add, then see if the extremal
	147	* changed
	148	*/
	149	plist_del(node, &o->requests);
	150	plist_node_init(node, value);
	151	plist_add(node, &o->requests);
	152	} else if (del) {
	153	plist_del(node, &o->requests);
	154	} else {
	155	plist_add(node, &o->requests);
d82b3518	156	}
5f279845	157	curr_value = pm_qos_get_value(o);
d82b3518 MG	158	spin_unlock_irqrestore(&pm_qos_lock, flags);
d82b3518 MG	159
5f279845 JB	160	if (prev_value != curr_value)
	161	blocking_notifier_call_chain(o->notifiers,
	162	(unsigned long)curr_value,
	163	NULL);
d82b3518 MG	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	/**
ed77134b	189	* pm_qos_request - returns current system wide qos expectation
d82b3518 MG	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	*/
ed77134b	194	int pm_qos_request(int pm_qos_class)
d82b3518	195	{
5f279845 JB	196	unsigned long flags;
	197	int value;
	198
	199	spin_lock_irqsave(&pm_qos_lock, flags);
	200	value = pm_qos_get_value(pm_qos_array[pm_qos_class]);
	201	spin_unlock_irqrestore(&pm_qos_lock, flags);
	202
	203	return value;
d82b3518	204	}
ed77134b	205	EXPORT_SYMBOL_GPL(pm_qos_request);
d82b3518	206
82f68251 JB	207	int pm_qos_request_active(struct pm_qos_request_list *req)
	208	{
	209	return req->pm_qos_class != 0;
	210	}
	211	EXPORT_SYMBOL_GPL(pm_qos_request_active);
	212
d82b3518	213	/**
ed77134b	214	* pm_qos_add_request - inserts new qos request into the list
25cc69ec SK	215	* @dep: pointer to a preallocated handle
25cc69ec SK	216	* @pm_qos_class: identifies which list of qos request to use
d82b3518 MG	217	* @value: defines the qos request
	218	*
	219	* This function inserts a new entry in the pm_qos_class list of requested qos
bf1db69f	220	* performance characteristics. It recomputes the aggregate QoS expectations
25cc69ec SK	221	* for the pm_qos_class of parameters and initializes the pm_qos_request_list
	222	* handle. Caller needs to save this handle for later use in updates and
	223	* removal.
d82b3518	224	*/
25cc69ec	225
82f68251 JB	226	void pm_qos_add_request(struct pm_qos_request_list *dep,
82f68251 JB	227	int pm_qos_class, s32 value)
d82b3518	228	{
82f68251 JB	229	struct pm_qos_object *o = pm_qos_array[pm_qos_class];
82f68251 JB	230	int new_value;
d82b3518	231
82f68251 JB	232	if (pm_qos_request_active(dep)) {
	233	WARN(1, KERN_ERR "pm_qos_add_request() called for already added request\n");
	234	return;
	235	}
	236	if (value == PM_QOS_DEFAULT_VALUE)
	237	new_value = o->default_value;
	238	else
	239	new_value = value;
	240	plist_node_init(&dep->list, new_value);
	241	dep->pm_qos_class = pm_qos_class;
	242	update_target(o, &dep->list, 0, PM_QOS_DEFAULT_VALUE);
d82b3518	243	}
ed77134b	244	EXPORT_SYMBOL_GPL(pm_qos_add_request);
d82b3518 MG	245
d82b3518 MG	246	/**
ed77134b MG	247	* pm_qos_update_request - modifies an existing qos request
ed77134b MG	248	* @pm_qos_req : handle to list element holding a pm_qos request to use
d82b3518 MG	249	* @value: defines the qos request
d82b3518 MG	250	*
ed77134b	251	* Updates an existing qos request for the pm_qos_class of parameters along
d82b3518 MG	252	* with updating the target pm_qos_class value.
d82b3518 MG	253	*
ed77134b	254	* Attempts are made to make this code callable on hot code paths.
d82b3518	255	*/
ed77134b	256	void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
5f279845	257	s32 new_value)
d82b3518	258	{
ed77134b	259	s32 temp;
5f279845	260	struct pm_qos_object *o;
d82b3518	261
5f279845 JB	262	if (!pm_qos_req) /guard against callers passing in null /
	263	return;
	264
82f68251 JB	265	if (!pm_qos_request_active(pm_qos_req)) {
	266	WARN(1, KERN_ERR "pm_qos_update_request() called for unknown object\n");
	267	return;
	268	}
	269
5f279845 JB	270	o = pm_qos_array[pm_qos_req->pm_qos_class];
	271
	272	if (new_value == PM_QOS_DEFAULT_VALUE)
	273	temp = o->default_value;
	274	else
	275	temp = new_value;
	276
	277	if (temp != pm_qos_req->list.prio)
	278	update_target(o, &pm_qos_req->list, 0, temp);
d82b3518	279	}
ed77134b	280	EXPORT_SYMBOL_GPL(pm_qos_update_request);
d82b3518 MG	281
d82b3518 MG	282	/**
ed77134b MG	283	* pm_qos_remove_request - modifies an existing qos request
ed77134b MG	284	* @pm_qos_req: handle to request list element
d82b3518	285	*
ed77134b MG	286	* Will remove pm qos request from the list of requests and
	287	* recompute the current target value for the pm_qos_class. Call this
	288	* on slow code paths.
d82b3518	289	*/
ed77134b	290	void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req)
d82b3518	291	{
5f279845	292	struct pm_qos_object *o;
ed77134b MG	293
	294	if (pm_qos_req == NULL)
	295	return;
	296	/* silent return to keep pcm code cleaner */
d82b3518	297
82f68251 JB	298	if (!pm_qos_request_active(pm_qos_req)) {
	299	WARN(1, KERN_ERR "pm_qos_remove_request() called for unknown object\n");
	300	return;
	301	}
	302
5f279845 JB	303	o = pm_qos_array[pm_qos_req->pm_qos_class];
5f279845 JB	304	update_target(o, &pm_qos_req->list, 1, PM_QOS_DEFAULT_VALUE);
82f68251	305	memset(pm_qos_req, 0, sizeof(*pm_qos_req));
d82b3518	306	}
ed77134b	307	EXPORT_SYMBOL_GPL(pm_qos_remove_request);
d82b3518 MG	308
	309	/**
	310	* pm_qos_add_notifier - sets notification entry for changes to target value
	311	* @pm_qos_class: identifies which qos target changes should be notified.
	312	* @notifier: notifier block managed by caller.
	313	*
	314	* will register the notifier into a notification chain that gets called
bf1db69f	315	* upon changes to the pm_qos_class target value.
d82b3518	316	*/
ed77134b	317	int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
d82b3518 MG	318	{
	319	int retval;
	320
	321	retval = blocking_notifier_chain_register(
	322	pm_qos_array[pm_qos_class]->notifiers, notifier);
	323
	324	return retval;
	325	}
	326	EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
	327
	328	/**
	329	* pm_qos_remove_notifier - deletes notification entry from chain.
	330	* @pm_qos_class: identifies which qos target changes are notified.
	331	* @notifier: notifier block to be removed.
	332	*
	333	* will remove the notifier from the notification chain that gets called
bf1db69f	334	* upon changes to the pm_qos_class target value.
d82b3518 MG	335	*/
	336	int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
	337	{
	338	int retval;
	339
	340	retval = blocking_notifier_chain_unregister(
	341	pm_qos_array[pm_qos_class]->notifiers, notifier);
	342
	343	return retval;
	344	}
	345	EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
	346
d82b3518 MG	347	static int pm_qos_power_open(struct inode inode, struct file filp)
d82b3518 MG	348	{
d82b3518 MG	349	long pm_qos_class;
	350
	351	pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
	352	if (pm_qos_class >= 0) {
bac1e74d	353	struct pm_qos_request_list req = kzalloc(sizeof(req), GFP_KERNEL);
82f68251 JB	354	if (!req)
	355	return -ENOMEM;
	356
	357	pm_qos_add_request(req, pm_qos_class, PM_QOS_DEFAULT_VALUE);
	358	filp->private_data = req;
ed77134b MG	359
ed77134b MG	360	if (filp->private_data)
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	{
ed77134b	368	struct pm_qos_request_list *req;
d82b3518	369
82f68251	370	req = filp->private_data;
ed77134b	371	pm_qos_remove_request(req);
82f68251	372	kfree(req);
d82b3518 MG	373
	374	return 0;
	375	}
	376
ed77134b	377
d82b3518 MG	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;
ed77134b MG	382	int x;
	383	char ascii_value[11];
	384	struct pm_qos_request_list *pm_qos_req;
	385
	386	if (count == sizeof(s32)) {
	387	if (copy_from_user(&value, buf, sizeof(s32)))
	388	return -EFAULT;
	389	} else if (count == 11) { /* len('0x12345678/0') */
	390	if (copy_from_user(ascii_value, buf, 11))
	391	return -EFAULT;
	392	x = sscanf(ascii_value, "%x", &value);
	393	if (x != 1)
	394	return -EINVAL;
	395	pr_debug(KERN_ERR "%s, %d, 0x%x\n", ascii_value, x, value);
	396	} else
d82b3518	397	return -EINVAL;
d82b3518	398
ed77134b MG	399	pm_qos_req = (struct pm_qos_request_list *)filp->private_data;
	400	pm_qos_update_request(pm_qos_req, value);
	401
	402	return count;
d82b3518 MG	403	}
	404
	405
	406	static int __init pm_qos_power_init(void)
	407	{
	408	int ret = 0;
	409
	410	ret = register_pm_qos_misc(&cpu_dma_pm_qos);
	411	if (ret < 0) {
	412	printk(KERN_ERR "pm_qos_param: cpu_dma_latency setup failed\n");
	413	return ret;
	414	}
	415	ret = register_pm_qos_misc(&network_lat_pm_qos);
	416	if (ret < 0) {
	417	printk(KERN_ERR "pm_qos_param: network_latency setup failed\n");
	418	return ret;
	419	}
	420	ret = register_pm_qos_misc(&network_throughput_pm_qos);
	421	if (ret < 0)
	422	printk(KERN_ERR
	423	"pm_qos_param: network_throughput setup failed\n");
	424
	425	return ret;
	426	}
	427
	428	late_initcall(pm_qos_power_init);