[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
 */
struct pm_qos_request_list {
	struct list_head list;
	union {
		s32 value;
		s32 usec;
		s32 kbps;
	};
	int pm_qos_class;
};

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

struct pm_qos_object {
	struct pm_qos_request_list requests;
	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 = {
	.requests = {LIST_HEAD_INIT(cpu_dma_pm_qos.requests.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 = {
	.requests = {LIST_HEAD_INIT(network_lat_pm_qos.requests.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 = {
	.requests = {LIST_HEAD_INIT(network_throughput_pm_qos.requests.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 pm_qos_class)
{
	s32 extreme_value;
	struct pm_qos_request_list *node;
	unsigned long flags;
	int call_notifier = 0;

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

	if (call_notifier)
		blocking_notifier_call_chain(
				pm_qos_array[pm_qos_class]->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_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)
{
	return atomic_read(&pm_qos_array[pm_qos_class]->target_value);
}
EXPORT_SYMBOL_GPL(pm_qos_request);

/**
 * pm_qos_add_request - inserts new qos request into the list
 * @pm_qos_class: identifies which list of qos request to us
 * @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 returns the pm_qos_request list
 * element as a handle for use in updating and removal.  Call needs to save
 * this handle for later use.
 */
struct pm_qos_request_list *pm_qos_add_request(int pm_qos_class, s32 value)
{
	struct pm_qos_request_list *dep;
	unsigned long flags;

	dep = kzalloc(sizeof(struct pm_qos_request_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->pm_qos_class = pm_qos_class;

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

	return dep;
}
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)
{
	unsigned long flags;
	int pending_update = 0;
	s32 temp;

	if (pm_qos_req) { /*guard against callers passing in null */
		spin_lock_irqsave(&pm_qos_lock, flags);
		if (new_value == PM_QOS_DEFAULT_VALUE)
			temp = pm_qos_array[pm_qos_req->pm_qos_class]->default_value;
		else
			temp = new_value;

		if (temp != pm_qos_req->value) {
			pending_update = 1;
			pm_qos_req->value = temp;
		}
		spin_unlock_irqrestore(&pm_qos_lock, flags);
		if (pending_update)
			update_target(pm_qos_req->pm_qos_class);
	}
}
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)
{
	unsigned long flags;
	int qos_class;

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

	qos_class = pm_qos_req->pm_qos_class;
	spin_lock_irqsave(&pm_qos_lock, flags);
	list_del(&pm_qos_req->list);
	kfree(pm_qos_req);
	spin_unlock_irqrestore(&pm_qos_lock, flags);
	update_target(qos_class);
}
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) {
		filp->private_data = (void *) pm_qos_add_request(pm_qos_class,
				PM_QOS_DEFAULT_VALUE);

		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 = (struct pm_qos_request_list *)filp->private_data;
	pm_qos_remove_request(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	*/
ed77134b	51	struct pm_qos_request_list {
d82b3518 MG	52	struct list_head list;
	53	union {
	54	s32 value;
	55	s32 usec;
	56	s32 kbps;
	57	};
ed77134b	58	int pm_qos_class;
d82b3518 MG	59	};
	60
	61	static s32 max_compare(s32 v1, s32 v2);
	62	static s32 min_compare(s32 v1, s32 v2);
	63
	64	struct pm_qos_object {
ed77134b	65	struct pm_qos_request_list requests;
d82b3518 MG	66	struct blocking_notifier_head *notifiers;
	67	struct miscdevice pm_qos_power_miscdev;
	68	char *name;
	69	s32 default_value;
9d359357	70	atomic_t target_value;
d82b3518 MG	71	s32 (*comparitor)(s32, s32);
	72	};
	73
	74	static struct pm_qos_object null_pm_qos;
	75	static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
	76	static struct pm_qos_object cpu_dma_pm_qos = {
ed77134b	77	.requests = {LIST_HEAD_INIT(cpu_dma_pm_qos.requests.list)},
d82b3518 MG	78	.notifiers = &cpu_dma_lat_notifier,
	79	.name = "cpu_dma_latency",
	80	.default_value = 2000 * USEC_PER_SEC,
9d359357	81	.target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
d82b3518 MG	82	.comparitor = min_compare
	83	};
	84
	85	static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
	86	static struct pm_qos_object network_lat_pm_qos = {
ed77134b	87	.requests = {LIST_HEAD_INIT(network_lat_pm_qos.requests.list)},
d82b3518 MG	88	.notifiers = &network_lat_notifier,
	89	.name = "network_latency",
	90	.default_value = 2000 * USEC_PER_SEC,
9d359357	91	.target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
d82b3518 MG	92	.comparitor = min_compare
	93	};
	94
	95
	96	static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
	97	static struct pm_qos_object network_throughput_pm_qos = {
ed77134b	98	.requests = {LIST_HEAD_INIT(network_throughput_pm_qos.requests.list)},
d82b3518 MG	99	.notifiers = &network_throughput_notifier,
	100	.name = "network_throughput",
	101	.default_value = 0,
9d359357	102	.target_value = ATOMIC_INIT(0),
d82b3518 MG	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
ed77134b	139	static void update_target(int pm_qos_class)
d82b3518 MG	140	{
d82b3518 MG	141	s32 extreme_value;
ed77134b	142	struct pm_qos_request_list *node;
d82b3518 MG	143	unsigned long flags;
	144	int call_notifier = 0;
	145
	146	spin_lock_irqsave(&pm_qos_lock, flags);
ed77134b	147	extreme_value = pm_qos_array[pm_qos_class]->default_value;
d82b3518	148	list_for_each_entry(node,
ed77134b MG	149	&pm_qos_array[pm_qos_class]->requests.list, list) {
ed77134b MG	150	extreme_value = pm_qos_array[pm_qos_class]->comparitor(
d82b3518 MG	151	extreme_value, node->value);
d82b3518 MG	152	}
ed77134b MG	153	if (atomic_read(&pm_qos_array[pm_qos_class]->target_value) !=
ed77134b MG	154	extreme_value) {
d82b3518	155	call_notifier = 1;
ed77134b MG	156	atomic_set(&pm_qos_array[pm_qos_class]->target_value,
	157	extreme_value);
	158	pr_debug(KERN_ERR "new target for qos %d is %d\n", pm_qos_class,
	159	atomic_read(&pm_qos_array[pm_qos_class]->target_value));
d82b3518 MG	160	}
	161	spin_unlock_irqrestore(&pm_qos_lock, flags);
	162
	163	if (call_notifier)
ed77134b MG	164	blocking_notifier_call_chain(
	165	pm_qos_array[pm_qos_class]->notifiers,
	166	(unsigned long) extreme_value, NULL);
d82b3518 MG	167	}
	168
	169	static int register_pm_qos_misc(struct pm_qos_object *qos)
	170	{
	171	qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR;
	172	qos->pm_qos_power_miscdev.name = qos->name;
	173	qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops;
	174
	175	return misc_register(&qos->pm_qos_power_miscdev);
	176	}
	177
	178	static int find_pm_qos_object_by_minor(int minor)
	179	{
	180	int pm_qos_class;
	181
	182	for (pm_qos_class = 0;
	183	pm_qos_class < PM_QOS_NUM_CLASSES; pm_qos_class++) {
	184	if (minor ==
	185	pm_qos_array[pm_qos_class]->pm_qos_power_miscdev.minor)
	186	return pm_qos_class;
	187	}
	188	return -1;
	189	}
	190
	191	/**
ed77134b	192	* pm_qos_request - returns current system wide qos expectation
d82b3518 MG	193	* @pm_qos_class: identification of which qos value is requested
	194	*
	195	* This function returns the current target value in an atomic manner.
	196	*/
ed77134b	197	int pm_qos_request(int pm_qos_class)
d82b3518	198	{
9d359357	199	return atomic_read(&pm_qos_array[pm_qos_class]->target_value);
d82b3518	200	}
ed77134b	201	EXPORT_SYMBOL_GPL(pm_qos_request);
d82b3518 MG	202
d82b3518 MG	203	/**
ed77134b	204	* pm_qos_add_request - inserts new qos request into the list
d82b3518	205	* @pm_qos_class: identifies which list of qos request to us
d82b3518 MG	206	* @value: defines the qos request
	207	*
	208	* This function inserts a new entry in the pm_qos_class list of requested qos
bf1db69f	209	* performance characteristics. It recomputes the aggregate QoS expectations
ed77134b MG	210	* for the pm_qos_class of parameters, and returns the pm_qos_request list
	211	* element as a handle for use in updating and removal. Call needs to save
	212	* this handle for later use.
d82b3518	213	*/
ed77134b	214	struct pm_qos_request_list *pm_qos_add_request(int pm_qos_class, s32 value)
d82b3518	215	{
ed77134b	216	struct pm_qos_request_list *dep;
d82b3518 MG	217	unsigned long flags;
d82b3518 MG	218
ed77134b	219	dep = kzalloc(sizeof(struct pm_qos_request_list), GFP_KERNEL);
d82b3518 MG	220	if (dep) {
	221	if (value == PM_QOS_DEFAULT_VALUE)
	222	dep->value = pm_qos_array[pm_qos_class]->default_value;
	223	else
	224	dep->value = value;
ed77134b	225	dep->pm_qos_class = pm_qos_class;
d82b3518 MG	226
	227	spin_lock_irqsave(&pm_qos_lock, flags);
	228	list_add(&dep->list,
ed77134b	229	&pm_qos_array[pm_qos_class]->requests.list);
d82b3518 MG	230	spin_unlock_irqrestore(&pm_qos_lock, flags);
d82b3518 MG	231	update_target(pm_qos_class);
d82b3518 MG	232	}
d82b3518 MG	233
ed77134b	234	return dep;
d82b3518	235	}
ed77134b	236	EXPORT_SYMBOL_GPL(pm_qos_add_request);
d82b3518 MG	237
d82b3518 MG	238	/**
ed77134b MG	239	* pm_qos_update_request - modifies an existing qos request
ed77134b MG	240	* @pm_qos_req : handle to list element holding a pm_qos request to use
d82b3518 MG	241	* @value: defines the qos request
d82b3518 MG	242	*
ed77134b	243	* Updates an existing qos request for the pm_qos_class of parameters along
d82b3518 MG	244	* with updating the target pm_qos_class value.
d82b3518 MG	245	*
ed77134b	246	* Attempts are made to make this code callable on hot code paths.
d82b3518	247	*/
ed77134b MG	248	void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
ed77134b MG	249	s32 new_value)
d82b3518 MG	250	{
d82b3518 MG	251	unsigned long flags;
d82b3518	252	int pending_update = 0;
ed77134b	253	s32 temp;
d82b3518	254
25f3a5a2 MG	255	if (pm_qos_req) { /guard against callers passing in null /
	256	spin_lock_irqsave(&pm_qos_lock, flags);
	257	if (new_value == PM_QOS_DEFAULT_VALUE)
	258	temp = pm_qos_array[pm_qos_req->pm_qos_class]->default_value;
	259	else
	260	temp = new_value;
	261
	262	if (temp != pm_qos_req->value) {
	263	pending_update = 1;
	264	pm_qos_req->value = temp;
	265	}
	266	spin_unlock_irqrestore(&pm_qos_lock, flags);
	267	if (pending_update)
	268	update_target(pm_qos_req->pm_qos_class);
d82b3518	269	}
d82b3518	270	}
ed77134b	271	EXPORT_SYMBOL_GPL(pm_qos_update_request);
d82b3518 MG	272
d82b3518 MG	273	/**
ed77134b MG	274	* pm_qos_remove_request - modifies an existing qos request
ed77134b MG	275	* @pm_qos_req: handle to request list element
d82b3518	276	*
ed77134b MG	277	* Will remove pm qos request from the list of requests and
	278	* recompute the current target value for the pm_qos_class. Call this
	279	* on slow code paths.
d82b3518	280	*/
ed77134b	281	void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req)
d82b3518 MG	282	{
d82b3518 MG	283	unsigned long flags;
ed77134b MG	284	int qos_class;
	285
	286	if (pm_qos_req == NULL)
	287	return;
	288	/* silent return to keep pcm code cleaner */
d82b3518	289
ed77134b	290	qos_class = pm_qos_req->pm_qos_class;
d82b3518	291	spin_lock_irqsave(&pm_qos_lock, flags);
ed77134b MG	292	list_del(&pm_qos_req->list);
ed77134b MG	293	kfree(pm_qos_req);
d82b3518	294	spin_unlock_irqrestore(&pm_qos_lock, flags);
ed77134b	295	update_target(qos_class);
d82b3518	296	}
ed77134b	297	EXPORT_SYMBOL_GPL(pm_qos_remove_request);
d82b3518 MG	298
	299	/**
	300	* pm_qos_add_notifier - sets notification entry for changes to target value
	301	* @pm_qos_class: identifies which qos target changes should be notified.
	302	* @notifier: notifier block managed by caller.
	303	*
	304	* will register the notifier into a notification chain that gets called
bf1db69f	305	* upon changes to the pm_qos_class target value.
d82b3518	306	*/
ed77134b	307	int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
d82b3518 MG	308	{
	309	int retval;
	310
	311	retval = blocking_notifier_chain_register(
	312	pm_qos_array[pm_qos_class]->notifiers, notifier);
	313
	314	return retval;
	315	}
	316	EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
	317
	318	/**
	319	* pm_qos_remove_notifier - deletes notification entry from chain.
	320	* @pm_qos_class: identifies which qos target changes are notified.
	321	* @notifier: notifier block to be removed.
	322	*
	323	* will remove the notifier from the notification chain that gets called
bf1db69f	324	* upon changes to the pm_qos_class target value.
d82b3518 MG	325	*/
	326	int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
	327	{
	328	int retval;
	329
	330	retval = blocking_notifier_chain_unregister(
	331	pm_qos_array[pm_qos_class]->notifiers, notifier);
	332
	333	return retval;
	334	}
	335	EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
	336
d82b3518 MG	337	static int pm_qos_power_open(struct inode inode, struct file filp)
d82b3518 MG	338	{
d82b3518 MG	339	long pm_qos_class;
	340
	341	pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
	342	if (pm_qos_class >= 0) {
ed77134b MG	343	filp->private_data = (void *) pm_qos_add_request(pm_qos_class,
	344	PM_QOS_DEFAULT_VALUE);
	345
	346	if (filp->private_data)
d82b3518 MG	347	return 0;
d82b3518 MG	348	}
d82b3518 MG	349	return -EPERM;
	350	}
	351
	352	static int pm_qos_power_release(struct inode inode, struct file filp)
	353	{
ed77134b	354	struct pm_qos_request_list *req;
d82b3518	355
ed77134b MG	356	req = (struct pm_qos_request_list *)filp->private_data;
ed77134b MG	357	pm_qos_remove_request(req);
d82b3518 MG	358
	359	return 0;
	360	}
	361
ed77134b	362
d82b3518 MG	363	static ssize_t pm_qos_power_write(struct file filp, const char __user buf,
	364	size_t count, loff_t *f_pos)
	365	{
	366	s32 value;
ed77134b MG	367	int x;
	368	char ascii_value[11];
	369	struct pm_qos_request_list *pm_qos_req;
	370
	371	if (count == sizeof(s32)) {
	372	if (copy_from_user(&value, buf, sizeof(s32)))
	373	return -EFAULT;
	374	} else if (count == 11) { /* len('0x12345678/0') */
	375	if (copy_from_user(ascii_value, buf, 11))
	376	return -EFAULT;
	377	x = sscanf(ascii_value, "%x", &value);
	378	if (x != 1)
	379	return -EINVAL;
	380	pr_debug(KERN_ERR "%s, %d, 0x%x\n", ascii_value, x, value);
	381	} else
d82b3518	382	return -EINVAL;
d82b3518	383
ed77134b MG	384	pm_qos_req = (struct pm_qos_request_list *)filp->private_data;
	385	pm_qos_update_request(pm_qos_req, value);
	386
	387	return count;
d82b3518 MG	388	}
	389
	390
	391	static int __init pm_qos_power_init(void)
	392	{
	393	int ret = 0;
	394
	395	ret = register_pm_qos_misc(&cpu_dma_pm_qos);
	396	if (ret < 0) {
	397	printk(KERN_ERR "pm_qos_param: cpu_dma_latency setup failed\n");
	398	return ret;
	399	}
	400	ret = register_pm_qos_misc(&network_lat_pm_qos);
	401	if (ret < 0) {
	402	printk(KERN_ERR "pm_qos_param: network_latency setup failed\n");
	403	return ret;
	404	}
	405	ret = register_pm_qos_misc(&network_throughput_pm_qos);
	406	if (ret < 0)
	407	printk(KERN_ERR
	408	"pm_qos_param: network_throughput setup failed\n");
	409
	410	return ret;
	411	}
	412
	413	late_initcall(pm_qos_power_init);