[deliverable/linux.git] / drivers / dca / dca-core.c

/*
 * Copyright(c) 2007 - 2009 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>
#include <linux/slab.h>

#define DCA_VERSION "1.12.1"

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

static DEFINE_SPINLOCK(dca_lock);

static LIST_HEAD(dca_domains);

static BLOCKING_NOTIFIER_HEAD(dca_provider_chain);

static int dca_providers_blocked;

static struct pci_bus *dca_pci_rc_from_dev(struct device *dev)
{
	struct pci_dev *pdev = to_pci_dev(dev);
	struct pci_bus *bus = pdev->bus;

	while (bus->parent)
		bus = bus->parent;

	return bus;
}

static struct dca_domain *dca_allocate_domain(struct pci_bus *rc)
{
	struct dca_domain *domain;

	domain = kzalloc(sizeof(*domain), GFP_NOWAIT);
	if (!domain)
		return NULL;

	INIT_LIST_HEAD(&domain->dca_providers);
	domain->pci_rc = rc;

	return domain;
}

static void dca_free_domain(struct dca_domain *domain)
{
	list_del(&domain->node);
	kfree(domain);
}

static int dca_provider_ioat_ver_3_0(struct device *dev)
{
	struct pci_dev *pdev = to_pci_dev(dev);

	return ((pdev->vendor == PCI_VENDOR_ID_INTEL) &&
		((pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG0) ||
		(pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG1) ||
		(pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG2) ||
		(pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG3) ||
		(pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG4) ||
		(pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG5) ||
		(pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG6) ||
		(pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG7)));
}

static void unregister_dca_providers(void)
{
	struct dca_provider *dca, *_dca;
	struct list_head unregistered_providers;
	struct dca_domain *domain;
	unsigned long flags;

	blocking_notifier_call_chain(&dca_provider_chain,
				     DCA_PROVIDER_REMOVE, NULL);

	INIT_LIST_HEAD(&unregistered_providers);

	spin_lock_irqsave(&dca_lock, flags);

	if (list_empty(&dca_domains)) {
		spin_unlock_irqrestore(&dca_lock, flags);
		return;
	}

	/* at this point only one domain in the list is expected */
	domain = list_first_entry(&dca_domains, struct dca_domain, node);

	list_for_each_entry_safe(dca, _dca, &domain->dca_providers, node)
		list_move(&dca->node, &unregistered_providers);

	dca_free_domain(domain);

	spin_unlock_irqrestore(&dca_lock, flags);

	list_for_each_entry_safe(dca, _dca, &unregistered_providers, node) {
		dca_sysfs_remove_provider(dca);
		list_del(&dca->node);
	}
}

static struct dca_domain *dca_find_domain(struct pci_bus *rc)
{
	struct dca_domain *domain;

	list_for_each_entry(domain, &dca_domains, node)
		if (domain->pci_rc == rc)
			return domain;

	return NULL;
}

static struct dca_domain *dca_get_domain(struct device *dev)
{
	struct pci_bus *rc;
	struct dca_domain *domain;

	rc = dca_pci_rc_from_dev(dev);
	domain = dca_find_domain(rc);

	if (!domain) {
		if (dca_provider_ioat_ver_3_0(dev) && !list_empty(&dca_domains)) {
			dca_providers_blocked = 1;
		} else {
			domain = dca_allocate_domain(rc);
			if (domain)
				list_add(&domain->node, &dca_domains);
		}
	}

	return domain;
}

static struct dca_provider *dca_find_provider_by_dev(struct device *dev)
{
	struct dca_provider *dca;
	struct pci_bus *rc;
	struct dca_domain *domain;

	if (dev) {
		rc = dca_pci_rc_from_dev(dev);
		domain = dca_find_domain(rc);
		if (!domain)
			return NULL;
	} else {
		if (!list_empty(&dca_domains))
			domain = list_first_entry(&dca_domains,
						  struct dca_domain,
						  node);
		else
			return NULL;
	}

	list_for_each_entry(dca, &domain->dca_providers, node)
		if ((!dev) || (dca->ops->dev_managed(dca, dev)))
			return dca;

	return NULL;
}

/**
 * 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;
	unsigned long flags;
	struct pci_bus *pci_rc;
	struct dca_domain *domain;

	if (!dev)
		return -EFAULT;

	spin_lock_irqsave(&dca_lock, flags);

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

	pci_rc = dca_pci_rc_from_dev(dev);
	domain = dca_find_domain(pci_rc);
	if (!domain) {
		spin_unlock_irqrestore(&dca_lock, flags);
		return -ENODEV;
	}

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

	spin_unlock_irqrestore(&dca_lock, flags);

	if (slot < 0)
		return slot;

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

	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;
	unsigned long flags;

	if (!dev)
		return -EFAULT;

	spin_lock_irqsave(&dca_lock, flags);
	dca = dca_find_provider_by_dev(dev);
	if (!dca) {
		spin_unlock_irqrestore(&dca_lock, flags);
		return -ENODEV;
	}
	slot = dca->ops->remove_requester(dca, dev);
	spin_unlock_irqrestore(&dca_lock, flags);

	if (slot < 0)
		return slot;

	dca_sysfs_remove_req(dca, slot);

	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;
	unsigned long flags;

	spin_lock_irqsave(&dca_lock, flags);

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

	spin_unlock_irqrestore(&dca_lock, flags);
	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);

/**
 * 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;
	unsigned long flags;
	struct dca_domain *domain;

	spin_lock_irqsave(&dca_lock, flags);
	if (dca_providers_blocked) {
		spin_unlock_irqrestore(&dca_lock, flags);
		return -ENODEV;
	}
	spin_unlock_irqrestore(&dca_lock, flags);

	err = dca_sysfs_add_provider(dca, dev);
	if (err)
		return err;

	spin_lock_irqsave(&dca_lock, flags);
	domain = dca_get_domain(dev);
	if (!domain) {
		if (dca_providers_blocked) {
			spin_unlock_irqrestore(&dca_lock, flags);
			dca_sysfs_remove_provider(dca);
			unregister_dca_providers();
		} else {
			spin_unlock_irqrestore(&dca_lock, flags);
		}
		return -ENODEV;
	}
	list_add(&dca->node, &domain->dca_providers);
	spin_unlock_irqrestore(&dca_lock, flags);

	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, struct device *dev)
{
	unsigned long flags;
	struct pci_bus *pci_rc;
	struct dca_domain *domain;

	blocking_notifier_call_chain(&dca_provider_chain,
				     DCA_PROVIDER_REMOVE, NULL);

	spin_lock_irqsave(&dca_lock, flags);

	list_del(&dca->node);

	pci_rc = dca_pci_rc_from_dev(dev);
	domain = dca_find_domain(pci_rc);
	if (list_empty(&domain->dca_providers))
		dca_free_domain(domain);

	spin_unlock_irqrestore(&dca_lock, flags);

	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)
{
	pr_info("dca service started, version %s\n", DCA_VERSION);
	return dca_sysfs_init();
}

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

arch_initcall(dca_init);
module_exit(dca_exit);
Commit	Line	Data
7589670f	1	/*
211a22ce	2	* Copyright(c) 2007 - 2009 Intel Corporation. All rights reserved.
7589670f SN	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>
5a0e3ad6	30	#include <linux/slab.h>
7589670f	31
1a5aeeec	32	#define DCA_VERSION "1.12.1"
7589670f	33
7f1b358a MS	34	MODULE_VERSION(DCA_VERSION);
	35	MODULE_LICENSE("GPL");
	36	MODULE_AUTHOR("Intel Corporation");
7589670f SN	37
	38	static DEFINE_SPINLOCK(dca_lock);
	39
1a5aeeec	40	static LIST_HEAD(dca_domains);
7f1b358a	41
4e8cec26 SM	42	static BLOCKING_NOTIFIER_HEAD(dca_provider_chain);
	43
	44	static int dca_providers_blocked;
	45
1a5aeeec	46	static struct pci_bus dca_pci_rc_from_dev(struct device dev)
7f1b358a	47	{
1a5aeeec MS	48	struct pci_dev *pdev = to_pci_dev(dev);
1a5aeeec MS	49	struct pci_bus *bus = pdev->bus;
7f1b358a	50
1a5aeeec MS	51	while (bus->parent)
	52	bus = bus->parent;
	53
	54	return bus;
	55	}
	56
	57	static struct dca_domain dca_allocate_domain(struct pci_bus rc)
	58	{
	59	struct dca_domain *domain;
	60
	61	domain = kzalloc(sizeof(*domain), GFP_NOWAIT);
	62	if (!domain)
	63	return NULL;
	64
	65	INIT_LIST_HEAD(&domain->dca_providers);
	66	domain->pci_rc = rc;
	67
	68	return domain;
	69	}
	70
	71	static void dca_free_domain(struct dca_domain *domain)
	72	{
	73	list_del(&domain->node);
	74	kfree(domain);
	75	}
	76
4e8cec26 SM	77	static int dca_provider_ioat_ver_3_0(struct device *dev)
	78	{
	79	struct pci_dev *pdev = to_pci_dev(dev);
	80
	81	return ((pdev->vendor == PCI_VENDOR_ID_INTEL) &&
	82	((pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG0) \|\|
	83	(pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG1) \|\|
	84	(pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG2) \|\|
	85	(pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG3) \|\|
	86	(pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG4) \|\|
	87	(pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG5) \|\|
	88	(pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG6) \|\|
	89	(pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG7)));
	90	}
	91
	92	static void unregister_dca_providers(void)
	93	{
	94	struct dca_provider dca, _dca;
	95	struct list_head unregistered_providers;
	96	struct dca_domain *domain;
	97	unsigned long flags;
	98
	99	blocking_notifier_call_chain(&dca_provider_chain,
	100	DCA_PROVIDER_REMOVE, NULL);
	101
	102	INIT_LIST_HEAD(&unregistered_providers);
	103
	104	spin_lock_irqsave(&dca_lock, flags);
	105
	106	if (list_empty(&dca_domains)) {
	107	spin_unlock_irqrestore(&dca_lock, flags);
	108	return;
	109	}
	110
	111	/* at this point only one domain in the list is expected */
	112	domain = list_first_entry(&dca_domains, struct dca_domain, node);
4e8cec26	113
3bb598fb KS	114	list_for_each_entry_safe(dca, _dca, &domain->dca_providers, node)
3bb598fb KS	115	list_move(&dca->node, &unregistered_providers);
4e8cec26 SM	116
	117	dca_free_domain(domain);
	118
	119	spin_unlock_irqrestore(&dca_lock, flags);
	120
	121	list_for_each_entry_safe(dca, _dca, &unregistered_providers, node) {
	122	dca_sysfs_remove_provider(dca);
	123	list_del(&dca->node);
	124	}
	125	}
	126
1a5aeeec MS	127	static struct dca_domain dca_find_domain(struct pci_bus rc)
	128	{
	129	struct dca_domain *domain;
	130
	131	list_for_each_entry(domain, &dca_domains, node)
	132	if (domain->pci_rc == rc)
	133	return domain;
	134
	135	return NULL;
	136	}
	137
	138	static struct dca_domain dca_get_domain(struct device dev)
	139	{
	140	struct pci_bus *rc;
	141	struct dca_domain *domain;
	142
	143	rc = dca_pci_rc_from_dev(dev);
	144	domain = dca_find_domain(rc);
	145
	146	if (!domain) {
4e8cec26 SM	147	if (dca_provider_ioat_ver_3_0(dev) && !list_empty(&dca_domains)) {
	148	dca_providers_blocked = 1;
	149	} else {
	150	domain = dca_allocate_domain(rc);
	151	if (domain)
	152	list_add(&domain->node, &dca_domains);
	153	}
1a5aeeec MS	154	}
	155
	156	return domain;
	157	}
	158
	159	static struct dca_provider dca_find_provider_by_dev(struct device dev)
	160	{
	161	struct dca_provider *dca;
	162	struct pci_bus *rc;
	163	struct dca_domain *domain;
	164
	165	if (dev) {
	166	rc = dca_pci_rc_from_dev(dev);
	167	domain = dca_find_domain(rc);
	168	if (!domain)
	169	return NULL;
	170	} else {
	171	if (!list_empty(&dca_domains))
	172	domain = list_first_entry(&dca_domains,
	173	struct dca_domain,
	174	node);
	175	else
	176	return NULL;
7f1b358a MS	177	}
7f1b358a MS	178
1a5aeeec MS	179	list_for_each_entry(dca, &domain->dca_providers, node)
	180	if ((!dev) \|\| (dca->ops->dev_managed(dca, dev)))
	181	return dca;
	182
	183	return NULL;
7f1b358a	184	}
7589670f SN	185
	186	/**
	187	* dca_add_requester - add a dca client to the list
	188	* @dev - the device that wants dca service
	189	*/
	190	int dca_add_requester(struct device *dev)
	191	{
7f1b358a MS	192	struct dca_provider *dca;
7f1b358a MS	193	int err, slot = -ENODEV;
eb4400e3	194	unsigned long flags;
1a5aeeec MS	195	struct pci_bus *pci_rc;
1a5aeeec MS	196	struct dca_domain *domain;
7589670f	197
7f1b358a MS	198	if (!dev)
7f1b358a MS	199	return -EFAULT;
7589670f	200
eb4400e3	201	spin_lock_irqsave(&dca_lock, flags);
7f1b358a MS	202
	203	/* check if the requester has not been added already */
	204	dca = dca_find_provider_by_dev(dev);
	205	if (dca) {
eb4400e3	206	spin_unlock_irqrestore(&dca_lock, flags);
7f1b358a MS	207	return -EEXIST;
	208	}
	209
1a5aeeec MS	210	pci_rc = dca_pci_rc_from_dev(dev);
	211	domain = dca_find_domain(pci_rc);
	212	if (!domain) {
	213	spin_unlock_irqrestore(&dca_lock, flags);
	214	return -ENODEV;
	215	}
	216
	217	list_for_each_entry(dca, &domain->dca_providers, node) {
7f1b358a MS	218	slot = dca->ops->add_requester(dca, dev);
	219	if (slot >= 0)
	220	break;
	221	}
eb4400e3 MS	222
	223	spin_unlock_irqrestore(&dca_lock, flags);
	224
	225	if (slot < 0)
7589670f SN	226	return slot;
7589670f SN	227
7f1b358a	228	err = dca_sysfs_add_req(dca, dev, slot);
7589670f	229	if (err) {
eb4400e3 MS	230	spin_lock_irqsave(&dca_lock, flags);
	231	if (dca == dca_find_provider_by_dev(dev))
	232	dca->ops->remove_requester(dca, dev);
	233	spin_unlock_irqrestore(&dca_lock, flags);
7589670f SN	234	return err;
	235	}
	236
	237	return 0;
	238	}
	239	EXPORT_SYMBOL_GPL(dca_add_requester);
	240
	241	/**
	242	* dca_remove_requester - remove a dca client from the list
	243	* @dev - the device that wants dca service
	244	*/
	245	int dca_remove_requester(struct device *dev)
	246	{
7f1b358a	247	struct dca_provider *dca;
7589670f	248	int slot;
eb4400e3	249	unsigned long flags;
7f1b358a MS	250
	251	if (!dev)
	252	return -EFAULT;
7589670f	253
eb4400e3	254	spin_lock_irqsave(&dca_lock, flags);
7f1b358a MS	255	dca = dca_find_provider_by_dev(dev);
7f1b358a MS	256	if (!dca) {
eb4400e3	257	spin_unlock_irqrestore(&dca_lock, flags);
7f1b358a MS	258	return -ENODEV;
	259	}
	260	slot = dca->ops->remove_requester(dca, dev);
eb4400e3 MS	261	spin_unlock_irqrestore(&dca_lock, flags);
	262
	263	if (slot < 0)
7589670f SN	264	return slot;
7589670f SN	265
7f1b358a MS	266	dca_sysfs_remove_req(dca, slot);
7f1b358a MS	267
7589670f SN	268	return 0;
	269	}
	270	EXPORT_SYMBOL_GPL(dca_remove_requester);
	271
	272	/**
7f1b358a MS	273	* dca_common_get_tag - return the dca tag (serves both new and old api)
7f1b358a MS	274	* @dev - the device that wants dca service
7589670f SN	275	* @cpu - the cpuid as returned by get_cpu()
7589670f SN	276	*/
7f1b358a	277	u8 dca_common_get_tag(struct device *dev, int cpu)
7589670f	278	{
7f1b358a MS	279	struct dca_provider *dca;
7f1b358a MS	280	u8 tag;
eb4400e3	281	unsigned long flags;
7f1b358a	282
eb4400e3	283	spin_lock_irqsave(&dca_lock, flags);
7f1b358a MS	284
	285	dca = dca_find_provider_by_dev(dev);
	286	if (!dca) {
eb4400e3	287	spin_unlock_irqrestore(&dca_lock, flags);
7589670f	288	return -ENODEV;
7f1b358a MS	289	}
	290	tag = dca->ops->get_tag(dca, dev, cpu);
	291
eb4400e3	292	spin_unlock_irqrestore(&dca_lock, flags);
7f1b358a MS	293	return tag;
	294	}
	295
	296	/**
	297	* dca3_get_tag - return the dca tag to the requester device
	298	* for the given cpu (new api)
	299	* @dev - the device that wants dca service
	300	* @cpu - the cpuid as returned by get_cpu()
	301	*/
	302	u8 dca3_get_tag(struct device *dev, int cpu)
	303	{
	304	if (!dev)
	305	return -EFAULT;
	306
	307	return dca_common_get_tag(dev, cpu);
	308	}
	309	EXPORT_SYMBOL_GPL(dca3_get_tag);
	310
	311	/**
	312	* dca_get_tag - return the dca tag for the given cpu (old api)
	313	* @cpu - the cpuid as returned by get_cpu()
	314	*/
	315	u8 dca_get_tag(int cpu)
	316	{
	317	struct device *dev = NULL;
	318
	319	return dca_common_get_tag(dev, cpu);
7589670f SN	320	}
	321	EXPORT_SYMBOL_GPL(dca_get_tag);
	322
	323	/**
	324	* alloc_dca_provider - get data struct for describing a dca provider
	325	* @ops - pointer to struct of dca operation function pointers
	326	* @priv_size - size of extra mem to be added for provider's needs
	327	*/
	328	struct dca_provider alloc_dca_provider(struct dca_ops ops, int priv_size)
	329	{
	330	struct dca_provider *dca;
	331	int alloc_size;
	332
	333	alloc_size = (sizeof(*dca) + priv_size);
	334	dca = kzalloc(alloc_size, GFP_KERNEL);
	335	if (!dca)
	336	return NULL;
	337	dca->ops = ops;
	338
	339	return dca;
	340	}
	341	EXPORT_SYMBOL_GPL(alloc_dca_provider);
	342
	343	/**
	344	* free_dca_provider - release the dca provider data struct
	345	* @ops - pointer to struct of dca operation function pointers
	346	* @priv_size - size of extra mem to be added for provider's needs
	347	*/
	348	void free_dca_provider(struct dca_provider *dca)
	349	{
	350	kfree(dca);
	351	}
	352	EXPORT_SYMBOL_GPL(free_dca_provider);
	353
7589670f SN	354	/**
	355	* register_dca_provider - register a dca provider
	356	* @dca - struct created by alloc_dca_provider()
	357	* @dev - device providing dca services
	358	*/
	359	int register_dca_provider(struct dca_provider dca, struct device dev)
	360	{
	361	int err;
eb4400e3	362	unsigned long flags;
1a5aeeec	363	struct dca_domain *domain;
7589670f	364
4e8cec26 SM	365	spin_lock_irqsave(&dca_lock, flags);
	366	if (dca_providers_blocked) {
	367	spin_unlock_irqrestore(&dca_lock, flags);
	368	return -ENODEV;
	369	}
	370	spin_unlock_irqrestore(&dca_lock, flags);
	371
7589670f SN	372	err = dca_sysfs_add_provider(dca, dev);
	373	if (err)
	374	return err;
eb4400e3 MS	375
eb4400e3 MS	376	spin_lock_irqsave(&dca_lock, flags);
1a5aeeec MS	377	domain = dca_get_domain(dev);
1a5aeeec MS	378	if (!domain) {
4e8cec26 SM	379	if (dca_providers_blocked) {
	380	spin_unlock_irqrestore(&dca_lock, flags);
	381	dca_sysfs_remove_provider(dca);
	382	unregister_dca_providers();
	383	} else {
	384	spin_unlock_irqrestore(&dca_lock, flags);
	385	}
1a5aeeec MS	386	return -ENODEV;
	387	}
	388	list_add(&dca->node, &domain->dca_providers);
eb4400e3 MS	389	spin_unlock_irqrestore(&dca_lock, flags);
eb4400e3 MS	390
7589670f SN	391	blocking_notifier_call_chain(&dca_provider_chain,
	392	DCA_PROVIDER_ADD, NULL);
	393	return 0;
	394	}
	395	EXPORT_SYMBOL_GPL(register_dca_provider);
	396
	397	/**
	398	* unregister_dca_provider - remove a dca provider
	399	* @dca - struct created by alloc_dca_provider()
	400	*/
1a5aeeec	401	void unregister_dca_provider(struct dca_provider dca, struct device dev)
7589670f	402	{
eb4400e3	403	unsigned long flags;
1a5aeeec MS	404	struct pci_bus *pci_rc;
1a5aeeec MS	405	struct dca_domain *domain;
eb4400e3	406
7589670f SN	407	blocking_notifier_call_chain(&dca_provider_chain,
7589670f SN	408	DCA_PROVIDER_REMOVE, NULL);
eb4400e3 MS	409
eb4400e3 MS	410	spin_lock_irqsave(&dca_lock, flags);
1a5aeeec	411
7f1b358a	412	list_del(&dca->node);
1a5aeeec MS	413
	414	pci_rc = dca_pci_rc_from_dev(dev);
	415	domain = dca_find_domain(pci_rc);
	416	if (list_empty(&domain->dca_providers))
	417	dca_free_domain(domain);
	418
eb4400e3 MS	419	spin_unlock_irqrestore(&dca_lock, flags);
eb4400e3 MS	420
7589670f SN	421	dca_sysfs_remove_provider(dca);
	422	}
	423	EXPORT_SYMBOL_GPL(unregister_dca_provider);
	424
	425	/**
	426	* dca_register_notify - register a client's notifier callback
	427	*/
	428	void dca_register_notify(struct notifier_block *nb)
	429	{
	430	blocking_notifier_chain_register(&dca_provider_chain, nb);
	431	}
	432	EXPORT_SYMBOL_GPL(dca_register_notify);
	433
	434	/**
	435	* dca_unregister_notify - remove a client's notifier callback
	436	*/
	437	void dca_unregister_notify(struct notifier_block *nb)
	438	{
	439	blocking_notifier_chain_unregister(&dca_provider_chain, nb);
	440	}
	441	EXPORT_SYMBOL_GPL(dca_unregister_notify);
	442
	443	static int __init dca_init(void)
	444	{
084dac53	445	pr_info("dca service started, version %s\n", DCA_VERSION);
7589670f SN	446	return dca_sysfs_init();
	447	}
	448
	449	static void __exit dca_exit(void)
	450	{
	451	dca_sysfs_exit();
	452	}
	453
652afc27	454	arch_initcall(dca_init);
7589670f SN	455	module_exit(dca_exit);
7589670f SN	456