[linux-2.6-block.git] / drivers / dca / dca-core.c

/*
 * Copyright(c) 2007 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59
 * Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * The full GNU General Public License is included in this distribution in the
 * file called COPYING.
 */

/*
 * This driver supports an interface for DCA clients and providers to meet.
 */

#include <linux/kernel.h>
#include <linux/notifier.h>
#include <linux/device.h>
#include <linux/dca.h>

#define DCA_VERSION "1.4"

MODULE_VERSION(DCA_VERSION);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Intel Corporation");

static DEFINE_SPINLOCK(dca_lock);

static LIST_HEAD(dca_providers);

static struct dca_provider *dca_find_provider_by_dev(struct device *dev)
{
	struct dca_provider *dca, *ret = NULL;

	list_for_each_entry(dca, &dca_providers, node) {
		if ((!dev) || (dca->ops->dev_managed(dca, dev))) {
			ret = dca;
			break;
		}
	}

	return ret;
}

/**
 * dca_add_requester - add a dca client to the list
 * @dev - the device that wants dca service
 */
int dca_add_requester(struct device *dev)
{
	struct dca_provider *dca;
	int err, slot = -ENODEV;

	if (!dev)
		return -EFAULT;

	spin_lock(&dca_lock);

	/* check if the requester has not been added already */
	dca = dca_find_provider_by_dev(dev);
	if (dca) {
		spin_unlock(&dca_lock);
		return -EEXIST;
	}

	list_for_each_entry(dca, &dca_providers, node) {
		slot = dca->ops->add_requester(dca, dev);
		if (slot >= 0)
			break;
	}
	if (slot < 0) {
		spin_unlock(&dca_lock);
		return slot;
	}

	err = dca_sysfs_add_req(dca, dev, slot);
	if (err) {
		dca->ops->remove_requester(dca, dev);
		spin_unlock(&dca_lock);
		return err;
	}

	spin_unlock(&dca_lock);
	return 0;
}
EXPORT_SYMBOL_GPL(dca_add_requester);

/**
 * dca_remove_requester - remove a dca client from the list
 * @dev - the device that wants dca service
 */
int dca_remove_requester(struct device *dev)
{
	struct dca_provider *dca;
	int slot;

	if (!dev)
		return -EFAULT;

	spin_lock(&dca_lock);
	dca = dca_find_provider_by_dev(dev);
	if (!dca) {
		spin_unlock(&dca_lock);
		return -ENODEV;
	}
	slot = dca->ops->remove_requester(dca, dev);
	if (slot < 0) {
		spin_unlock(&dca_lock);
		return slot;
	}

	dca_sysfs_remove_req(dca, slot);

	spin_unlock(&dca_lock);
	return 0;
}
EXPORT_SYMBOL_GPL(dca_remove_requester);

/**
 * dca_common_get_tag - return the dca tag (serves both new and old api)
 * @dev - the device that wants dca service
 * @cpu - the cpuid as returned by get_cpu()
 */
u8 dca_common_get_tag(struct device *dev, int cpu)
{
	struct dca_provider *dca;
	u8 tag;

	spin_lock(&dca_lock);

	dca = dca_find_provider_by_dev(dev);
	if (!dca) {
		spin_unlock(&dca_lock);
		return -ENODEV;
	}
	tag = dca->ops->get_tag(dca, dev, cpu);

	spin_unlock(&dca_lock);
	return tag;
}

/**
 * dca3_get_tag - return the dca tag to the requester device
 *                for the given cpu (new api)
 * @dev - the device that wants dca service
 * @cpu - the cpuid as returned by get_cpu()
 */
u8 dca3_get_tag(struct device *dev, int cpu)
{
	if (!dev)
		return -EFAULT;

	return dca_common_get_tag(dev, cpu);
}
EXPORT_SYMBOL_GPL(dca3_get_tag);

/**
 * dca_get_tag - return the dca tag for the given cpu (old api)
 * @cpu - the cpuid as returned by get_cpu()
 */
u8 dca_get_tag(int cpu)
{
	struct device *dev = NULL;

	return dca_common_get_tag(dev, cpu);
}
EXPORT_SYMBOL_GPL(dca_get_tag);

/**
 * alloc_dca_provider - get data struct for describing a dca provider
 * @ops - pointer to struct of dca operation function pointers
 * @priv_size - size of extra mem to be added for provider's needs
 */
struct dca_provider *alloc_dca_provider(struct dca_ops *ops, int priv_size)
{
	struct dca_provider *dca;
	int alloc_size;

	alloc_size = (sizeof(*dca) + priv_size);
	dca = kzalloc(alloc_size, GFP_KERNEL);
	if (!dca)
		return NULL;
	dca->ops = ops;

	return dca;
}
EXPORT_SYMBOL_GPL(alloc_dca_provider);

/**
 * free_dca_provider - release the dca provider data struct
 * @ops - pointer to struct of dca operation function pointers
 * @priv_size - size of extra mem to be added for provider's needs
 */
void free_dca_provider(struct dca_provider *dca)
{
	kfree(dca);
}
EXPORT_SYMBOL_GPL(free_dca_provider);

static BLOCKING_NOTIFIER_HEAD(dca_provider_chain);

/**
 * register_dca_provider - register a dca provider
 * @dca - struct created by alloc_dca_provider()
 * @dev - device providing dca services
 */
int register_dca_provider(struct dca_provider *dca, struct device *dev)
{
	int err;

	err = dca_sysfs_add_provider(dca, dev);
	if (err)
		return err;
	list_add(&dca->node, &dca_providers);
	blocking_notifier_call_chain(&dca_provider_chain,
				     DCA_PROVIDER_ADD, NULL);
	return 0;
}
EXPORT_SYMBOL_GPL(register_dca_provider);

/**
 * unregister_dca_provider - remove a dca provider
 * @dca - struct created by alloc_dca_provider()
 */
void unregister_dca_provider(struct dca_provider *dca)
{
	blocking_notifier_call_chain(&dca_provider_chain,
				     DCA_PROVIDER_REMOVE, NULL);
	list_del(&dca->node);
	dca_sysfs_remove_provider(dca);
}
EXPORT_SYMBOL_GPL(unregister_dca_provider);

/**
 * dca_register_notify - register a client's notifier callback
 */
void dca_register_notify(struct notifier_block *nb)
{
	blocking_notifier_chain_register(&dca_provider_chain, nb);
}
EXPORT_SYMBOL_GPL(dca_register_notify);

/**
 * dca_unregister_notify - remove a client's notifier callback
 */
void dca_unregister_notify(struct notifier_block *nb)
{
	blocking_notifier_chain_unregister(&dca_provider_chain, nb);
}
EXPORT_SYMBOL_GPL(dca_unregister_notify);

static int __init dca_init(void)
{
	printk(KERN_ERR "dca service started, version %s\n", DCA_VERSION);
	return dca_sysfs_init();
}

static void __exit dca_exit(void)
{
	dca_sysfs_exit();
}

subsys_initcall(dca_init);
module_exit(dca_exit);
Commit	Line	Data
7589670f SN	1	/*
	2	* Copyright(c) 2007 Intel Corporation. All rights reserved.
	3	*
	4	* This program is free software; you can redistribute it and/or modify it
	5	* under the terms of the GNU General Public License as published by the Free
	6	* Software Foundation; either version 2 of the License, or (at your option)
	7	* any later version.
	8	*
	9	* This program is distributed in the hope that it will be useful, but WITHOUT
	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	12	* more details.
	13	*
	14	* You should have received a copy of the GNU General Public License along with
	15	* this program; if not, write to the Free Software Foundation, Inc., 59
	16	* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	17	*
	18	* The full GNU General Public License is included in this distribution in the
	19	* file called COPYING.
	20	*/
	21
	22	/*
	23	* This driver supports an interface for DCA clients and providers to meet.
	24	*/
	25
	26	#include <linux/kernel.h>
	27	#include <linux/notifier.h>
	28	#include <linux/device.h>
	29	#include <linux/dca.h>
	30
7f1b358a	31	#define DCA_VERSION "1.4"
7589670f	32
7f1b358a MS	33	MODULE_VERSION(DCA_VERSION);
	34	MODULE_LICENSE("GPL");
	35	MODULE_AUTHOR("Intel Corporation");
7589670f SN	36
	37	static DEFINE_SPINLOCK(dca_lock);
	38
7f1b358a MS	39	static LIST_HEAD(dca_providers);
	40
	41	static struct dca_provider dca_find_provider_by_dev(struct device dev)
	42	{
	43	struct dca_provider dca, ret = NULL;
	44
	45	list_for_each_entry(dca, &dca_providers, node) {
	46	if ((!dev) \|\| (dca->ops->dev_managed(dca, dev))) {
	47	ret = dca;
	48	break;
	49	}
	50	}
	51
	52	return ret;
	53	}
7589670f SN	54
	55	/**
	56	* dca_add_requester - add a dca client to the list
	57	* @dev - the device that wants dca service
	58	*/
	59	int dca_add_requester(struct device *dev)
	60	{
7f1b358a MS	61	struct dca_provider *dca;
7f1b358a MS	62	int err, slot = -ENODEV;
7589670f	63
7f1b358a MS	64	if (!dev)
7f1b358a MS	65	return -EFAULT;
7589670f SN	66
7589670f SN	67	spin_lock(&dca_lock);
7f1b358a MS	68
	69	/* check if the requester has not been added already */
	70	dca = dca_find_provider_by_dev(dev);
	71	if (dca) {
	72	spin_unlock(&dca_lock);
	73	return -EEXIST;
	74	}
	75
	76	list_for_each_entry(dca, &dca_providers, node) {
	77	slot = dca->ops->add_requester(dca, dev);
	78	if (slot >= 0)
	79	break;
	80	}
	81	if (slot < 0) {
	82	spin_unlock(&dca_lock);
7589670f	83	return slot;
7f1b358a	84	}
7589670f	85
7f1b358a	86	err = dca_sysfs_add_req(dca, dev, slot);
7589670f	87	if (err) {
7f1b358a	88	dca->ops->remove_requester(dca, dev);
7589670f SN	89	spin_unlock(&dca_lock);
	90	return err;
	91	}
	92
7f1b358a	93	spin_unlock(&dca_lock);
7589670f SN	94	return 0;
	95	}
	96	EXPORT_SYMBOL_GPL(dca_add_requester);
	97
	98	/**
	99	* dca_remove_requester - remove a dca client from the list
	100	* @dev - the device that wants dca service
	101	*/
	102	int dca_remove_requester(struct device *dev)
	103	{
7f1b358a	104	struct dca_provider *dca;
7589670f	105	int slot;
7f1b358a MS	106
	107	if (!dev)
	108	return -EFAULT;
7589670f SN	109
7589670f SN	110	spin_lock(&dca_lock);
7f1b358a MS	111	dca = dca_find_provider_by_dev(dev);
	112	if (!dca) {
	113	spin_unlock(&dca_lock);
	114	return -ENODEV;
	115	}
	116	slot = dca->ops->remove_requester(dca, dev);
	117	if (slot < 0) {
	118	spin_unlock(&dca_lock);
7589670f	119	return slot;
7f1b358a	120	}
7589670f	121
7f1b358a MS	122	dca_sysfs_remove_req(dca, slot);
	123
	124	spin_unlock(&dca_lock);
7589670f SN	125	return 0;
	126	}
	127	EXPORT_SYMBOL_GPL(dca_remove_requester);
	128
	129	/**
7f1b358a MS	130	* dca_common_get_tag - return the dca tag (serves both new and old api)
7f1b358a MS	131	* @dev - the device that wants dca service
7589670f SN	132	* @cpu - the cpuid as returned by get_cpu()
7589670f SN	133	*/
7f1b358a	134	u8 dca_common_get_tag(struct device *dev, int cpu)
7589670f	135	{
7f1b358a MS	136	struct dca_provider *dca;
	137	u8 tag;
	138
	139	spin_lock(&dca_lock);
	140
	141	dca = dca_find_provider_by_dev(dev);
	142	if (!dca) {
	143	spin_unlock(&dca_lock);
7589670f	144	return -ENODEV;
7f1b358a MS	145	}
	146	tag = dca->ops->get_tag(dca, dev, cpu);
	147
	148	spin_unlock(&dca_lock);
	149	return tag;
	150	}
	151
	152	/**
	153	* dca3_get_tag - return the dca tag to the requester device
	154	* for the given cpu (new api)
	155	* @dev - the device that wants dca service
	156	* @cpu - the cpuid as returned by get_cpu()
	157	*/
	158	u8 dca3_get_tag(struct device *dev, int cpu)
	159	{
	160	if (!dev)
	161	return -EFAULT;
	162
	163	return dca_common_get_tag(dev, cpu);
	164	}
	165	EXPORT_SYMBOL_GPL(dca3_get_tag);
	166
	167	/**
	168	* dca_get_tag - return the dca tag for the given cpu (old api)
	169	* @cpu - the cpuid as returned by get_cpu()
	170	*/
	171	u8 dca_get_tag(int cpu)
	172	{
	173	struct device *dev = NULL;
	174
	175	return dca_common_get_tag(dev, cpu);
7589670f SN	176	}
	177	EXPORT_SYMBOL_GPL(dca_get_tag);
	178
	179	/**
	180	* alloc_dca_provider - get data struct for describing a dca provider
	181	* @ops - pointer to struct of dca operation function pointers
	182	* @priv_size - size of extra mem to be added for provider's needs
	183	*/
	184	struct dca_provider alloc_dca_provider(struct dca_ops ops, int priv_size)
	185	{
	186	struct dca_provider *dca;
	187	int alloc_size;
	188
	189	alloc_size = (sizeof(*dca) + priv_size);
	190	dca = kzalloc(alloc_size, GFP_KERNEL);
	191	if (!dca)
	192	return NULL;
	193	dca->ops = ops;
	194
	195	return dca;
	196	}
	197	EXPORT_SYMBOL_GPL(alloc_dca_provider);
	198
	199	/**
	200	* free_dca_provider - release the dca provider data struct
	201	* @ops - pointer to struct of dca operation function pointers
	202	* @priv_size - size of extra mem to be added for provider's needs
	203	*/
	204	void free_dca_provider(struct dca_provider *dca)
	205	{
	206	kfree(dca);
	207	}
	208	EXPORT_SYMBOL_GPL(free_dca_provider);
	209
	210	static BLOCKING_NOTIFIER_HEAD(dca_provider_chain);
	211
	212	/**
	213	* register_dca_provider - register a dca provider
	214	* @dca - struct created by alloc_dca_provider()
	215	* @dev - device providing dca services
	216	*/
	217	int register_dca_provider(struct dca_provider dca, struct device dev)
	218	{
	219	int err;
	220
7589670f SN	221	err = dca_sysfs_add_provider(dca, dev);
	222	if (err)
	223	return err;
7f1b358a	224	list_add(&dca->node, &dca_providers);
7589670f SN	225	blocking_notifier_call_chain(&dca_provider_chain,
	226	DCA_PROVIDER_ADD, NULL);
	227	return 0;
	228	}
	229	EXPORT_SYMBOL_GPL(register_dca_provider);
	230
	231	/**
	232	* unregister_dca_provider - remove a dca provider
	233	* @dca - struct created by alloc_dca_provider()
	234	*/
	235	void unregister_dca_provider(struct dca_provider *dca)
	236	{
7589670f SN	237	blocking_notifier_call_chain(&dca_provider_chain,
7589670f SN	238	DCA_PROVIDER_REMOVE, NULL);
7f1b358a	239	list_del(&dca->node);
7589670f SN	240	dca_sysfs_remove_provider(dca);
	241	}
	242	EXPORT_SYMBOL_GPL(unregister_dca_provider);
	243
	244	/**
	245	* dca_register_notify - register a client's notifier callback
	246	*/
	247	void dca_register_notify(struct notifier_block *nb)
	248	{
	249	blocking_notifier_chain_register(&dca_provider_chain, nb);
	250	}
	251	EXPORT_SYMBOL_GPL(dca_register_notify);
	252
	253	/**
	254	* dca_unregister_notify - remove a client's notifier callback
	255	*/
	256	void dca_unregister_notify(struct notifier_block *nb)
	257	{
	258	blocking_notifier_chain_unregister(&dca_provider_chain, nb);
	259	}
	260	EXPORT_SYMBOL_GPL(dca_unregister_notify);
	261
	262	static int __init dca_init(void)
	263	{
7f1b358a	264	printk(KERN_ERR "dca service started, version %s\n", DCA_VERSION);
7589670f SN	265	return dca_sysfs_init();
	266	}
	267
	268	static void __exit dca_exit(void)
	269	{
	270	dca_sysfs_exit();
	271	}
	272
1207e795	273	subsys_initcall(dca_init);
7589670f SN	274	module_exit(dca_exit);
7589670f SN	275