[net-next-2.6.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);
	if (!domain)
		return;

	list_for_each_entry_safe(dca, _dca, &domain->dca_providers, node) {
		list_del(&dca->node);
		list_add(&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);
	113	if (!domain)
	114	return;
	115
	116	list_for_each_entry_safe(dca, _dca, &domain->dca_providers, node) {
	117	list_del(&dca->node);
	118	list_add(&dca->node, &unregistered_providers);
	119	}
	120
	121	dca_free_domain(domain);
	122
	123	spin_unlock_irqrestore(&dca_lock, flags);
	124
	125	list_for_each_entry_safe(dca, _dca, &unregistered_providers, node) {
	126	dca_sysfs_remove_provider(dca);
	127	list_del(&dca->node);
	128	}
	129	}
	130
1a5aeeec MS	131	static struct dca_domain dca_find_domain(struct pci_bus rc)
	132	{
	133	struct dca_domain *domain;
	134
	135	list_for_each_entry(domain, &dca_domains, node)
	136	if (domain->pci_rc == rc)
	137	return domain;
	138
	139	return NULL;
	140	}
	141
	142	static struct dca_domain dca_get_domain(struct device dev)
	143	{
	144	struct pci_bus *rc;
	145	struct dca_domain *domain;
	146
	147	rc = dca_pci_rc_from_dev(dev);
	148	domain = dca_find_domain(rc);
	149
	150	if (!domain) {
4e8cec26 SM	151	if (dca_provider_ioat_ver_3_0(dev) && !list_empty(&dca_domains)) {
	152	dca_providers_blocked = 1;
	153	} else {
	154	domain = dca_allocate_domain(rc);
	155	if (domain)
	156	list_add(&domain->node, &dca_domains);
	157	}
1a5aeeec MS	158	}
	159
	160	return domain;
	161	}
	162
	163	static struct dca_provider dca_find_provider_by_dev(struct device dev)
	164	{
	165	struct dca_provider *dca;
	166	struct pci_bus *rc;
	167	struct dca_domain *domain;
	168
	169	if (dev) {
	170	rc = dca_pci_rc_from_dev(dev);
	171	domain = dca_find_domain(rc);
	172	if (!domain)
	173	return NULL;
	174	} else {
	175	if (!list_empty(&dca_domains))
	176	domain = list_first_entry(&dca_domains,
	177	struct dca_domain,
	178	node);
	179	else
	180	return NULL;
7f1b358a MS	181	}
7f1b358a MS	182
1a5aeeec MS	183	list_for_each_entry(dca, &domain->dca_providers, node)
	184	if ((!dev) \|\| (dca->ops->dev_managed(dca, dev)))
	185	return dca;
	186
	187	return NULL;
7f1b358a	188	}
7589670f SN	189
	190	/**
	191	* dca_add_requester - add a dca client to the list
	192	* @dev - the device that wants dca service
	193	*/
	194	int dca_add_requester(struct device *dev)
	195	{
7f1b358a MS	196	struct dca_provider *dca;
7f1b358a MS	197	int err, slot = -ENODEV;
eb4400e3	198	unsigned long flags;
1a5aeeec MS	199	struct pci_bus *pci_rc;
1a5aeeec MS	200	struct dca_domain *domain;
7589670f	201
7f1b358a MS	202	if (!dev)
7f1b358a MS	203	return -EFAULT;
7589670f	204
eb4400e3	205	spin_lock_irqsave(&dca_lock, flags);
7f1b358a MS	206
	207	/* check if the requester has not been added already */
	208	dca = dca_find_provider_by_dev(dev);
	209	if (dca) {
eb4400e3	210	spin_unlock_irqrestore(&dca_lock, flags);
7f1b358a MS	211	return -EEXIST;
	212	}
	213
1a5aeeec MS	214	pci_rc = dca_pci_rc_from_dev(dev);
	215	domain = dca_find_domain(pci_rc);
	216	if (!domain) {
	217	spin_unlock_irqrestore(&dca_lock, flags);
	218	return -ENODEV;
	219	}
	220
	221	list_for_each_entry(dca, &domain->dca_providers, node) {
7f1b358a MS	222	slot = dca->ops->add_requester(dca, dev);
	223	if (slot >= 0)
	224	break;
	225	}
eb4400e3 MS	226
	227	spin_unlock_irqrestore(&dca_lock, flags);
	228
	229	if (slot < 0)
7589670f SN	230	return slot;
7589670f SN	231
7f1b358a	232	err = dca_sysfs_add_req(dca, dev, slot);
7589670f	233	if (err) {
eb4400e3 MS	234	spin_lock_irqsave(&dca_lock, flags);
	235	if (dca == dca_find_provider_by_dev(dev))
	236	dca->ops->remove_requester(dca, dev);
	237	spin_unlock_irqrestore(&dca_lock, flags);
7589670f SN	238	return err;
	239	}
	240
	241	return 0;
	242	}
	243	EXPORT_SYMBOL_GPL(dca_add_requester);
	244
	245	/**
	246	* dca_remove_requester - remove a dca client from the list
	247	* @dev - the device that wants dca service
	248	*/
	249	int dca_remove_requester(struct device *dev)
	250	{
7f1b358a	251	struct dca_provider *dca;
7589670f	252	int slot;
eb4400e3	253	unsigned long flags;
7f1b358a MS	254
	255	if (!dev)
	256	return -EFAULT;
7589670f	257
eb4400e3	258	spin_lock_irqsave(&dca_lock, flags);
7f1b358a MS	259	dca = dca_find_provider_by_dev(dev);
7f1b358a MS	260	if (!dca) {
eb4400e3	261	spin_unlock_irqrestore(&dca_lock, flags);
7f1b358a MS	262	return -ENODEV;
	263	}
	264	slot = dca->ops->remove_requester(dca, dev);
eb4400e3 MS	265	spin_unlock_irqrestore(&dca_lock, flags);
	266
	267	if (slot < 0)
7589670f SN	268	return slot;
7589670f SN	269
7f1b358a MS	270	dca_sysfs_remove_req(dca, slot);
7f1b358a MS	271
7589670f SN	272	return 0;
	273	}
	274	EXPORT_SYMBOL_GPL(dca_remove_requester);
	275
	276	/**
7f1b358a MS	277	* dca_common_get_tag - return the dca tag (serves both new and old api)
7f1b358a MS	278	* @dev - the device that wants dca service
7589670f SN	279	* @cpu - the cpuid as returned by get_cpu()
7589670f SN	280	*/
7f1b358a	281	u8 dca_common_get_tag(struct device *dev, int cpu)
7589670f	282	{
7f1b358a MS	283	struct dca_provider *dca;
7f1b358a MS	284	u8 tag;
eb4400e3	285	unsigned long flags;
7f1b358a	286
eb4400e3	287	spin_lock_irqsave(&dca_lock, flags);
7f1b358a MS	288
	289	dca = dca_find_provider_by_dev(dev);
	290	if (!dca) {
eb4400e3	291	spin_unlock_irqrestore(&dca_lock, flags);
7589670f	292	return -ENODEV;
7f1b358a MS	293	}
	294	tag = dca->ops->get_tag(dca, dev, cpu);
	295
eb4400e3	296	spin_unlock_irqrestore(&dca_lock, flags);
7f1b358a MS	297	return tag;
	298	}
	299
	300	/**
	301	* dca3_get_tag - return the dca tag to the requester device
	302	* for the given cpu (new api)
	303	* @dev - the device that wants dca service
	304	* @cpu - the cpuid as returned by get_cpu()
	305	*/
	306	u8 dca3_get_tag(struct device *dev, int cpu)
	307	{
	308	if (!dev)
	309	return -EFAULT;
	310
	311	return dca_common_get_tag(dev, cpu);
	312	}
	313	EXPORT_SYMBOL_GPL(dca3_get_tag);
	314
	315	/**
	316	* dca_get_tag - return the dca tag for the given cpu (old api)
	317	* @cpu - the cpuid as returned by get_cpu()
	318	*/
	319	u8 dca_get_tag(int cpu)
	320	{
	321	struct device *dev = NULL;
	322
	323	return dca_common_get_tag(dev, cpu);
7589670f SN	324	}
	325	EXPORT_SYMBOL_GPL(dca_get_tag);
	326
	327	/**
	328	* alloc_dca_provider - get data struct for describing a dca provider
	329	* @ops - pointer to struct of dca operation function pointers
	330	* @priv_size - size of extra mem to be added for provider's needs
	331	*/
	332	struct dca_provider alloc_dca_provider(struct dca_ops ops, int priv_size)
	333	{
	334	struct dca_provider *dca;
	335	int alloc_size;
	336
	337	alloc_size = (sizeof(*dca) + priv_size);
	338	dca = kzalloc(alloc_size, GFP_KERNEL);
	339	if (!dca)
	340	return NULL;
	341	dca->ops = ops;
	342
	343	return dca;
	344	}
	345	EXPORT_SYMBOL_GPL(alloc_dca_provider);
	346
	347	/**
	348	* free_dca_provider - release the dca provider data struct
	349	* @ops - pointer to struct of dca operation function pointers
	350	* @priv_size - size of extra mem to be added for provider's needs
	351	*/
	352	void free_dca_provider(struct dca_provider *dca)
	353	{
	354	kfree(dca);
	355	}
	356	EXPORT_SYMBOL_GPL(free_dca_provider);
	357
7589670f SN	358	/**
	359	* register_dca_provider - register a dca provider
	360	* @dca - struct created by alloc_dca_provider()
	361	* @dev - device providing dca services
	362	*/
	363	int register_dca_provider(struct dca_provider dca, struct device dev)
	364	{
	365	int err;
eb4400e3	366	unsigned long flags;
1a5aeeec	367	struct dca_domain *domain;
7589670f	368
4e8cec26 SM	369	spin_lock_irqsave(&dca_lock, flags);
	370	if (dca_providers_blocked) {
	371	spin_unlock_irqrestore(&dca_lock, flags);
	372	return -ENODEV;
	373	}
	374	spin_unlock_irqrestore(&dca_lock, flags);
	375
7589670f SN	376	err = dca_sysfs_add_provider(dca, dev);
	377	if (err)
	378	return err;
eb4400e3 MS	379
eb4400e3 MS	380	spin_lock_irqsave(&dca_lock, flags);
1a5aeeec MS	381	domain = dca_get_domain(dev);
1a5aeeec MS	382	if (!domain) {
4e8cec26 SM	383	if (dca_providers_blocked) {
	384	spin_unlock_irqrestore(&dca_lock, flags);
	385	dca_sysfs_remove_provider(dca);
	386	unregister_dca_providers();
	387	} else {
	388	spin_unlock_irqrestore(&dca_lock, flags);
	389	}
1a5aeeec MS	390	return -ENODEV;
	391	}
	392	list_add(&dca->node, &domain->dca_providers);
eb4400e3 MS	393	spin_unlock_irqrestore(&dca_lock, flags);
eb4400e3 MS	394
7589670f SN	395	blocking_notifier_call_chain(&dca_provider_chain,
	396	DCA_PROVIDER_ADD, NULL);
	397	return 0;
	398	}
	399	EXPORT_SYMBOL_GPL(register_dca_provider);
	400
	401	/**
	402	* unregister_dca_provider - remove a dca provider
	403	* @dca - struct created by alloc_dca_provider()
	404	*/
1a5aeeec	405	void unregister_dca_provider(struct dca_provider dca, struct device dev)
7589670f	406	{
eb4400e3	407	unsigned long flags;
1a5aeeec MS	408	struct pci_bus *pci_rc;
1a5aeeec MS	409	struct dca_domain *domain;
eb4400e3	410
7589670f SN	411	blocking_notifier_call_chain(&dca_provider_chain,
7589670f SN	412	DCA_PROVIDER_REMOVE, NULL);
eb4400e3 MS	413
eb4400e3 MS	414	spin_lock_irqsave(&dca_lock, flags);
1a5aeeec	415
7f1b358a	416	list_del(&dca->node);
1a5aeeec MS	417
	418	pci_rc = dca_pci_rc_from_dev(dev);
	419	domain = dca_find_domain(pci_rc);
	420	if (list_empty(&domain->dca_providers))
	421	dca_free_domain(domain);
	422
eb4400e3 MS	423	spin_unlock_irqrestore(&dca_lock, flags);
eb4400e3 MS	424
7589670f SN	425	dca_sysfs_remove_provider(dca);
	426	}
	427	EXPORT_SYMBOL_GPL(unregister_dca_provider);
	428
	429	/**
	430	* dca_register_notify - register a client's notifier callback
	431	*/
	432	void dca_register_notify(struct notifier_block *nb)
	433	{
	434	blocking_notifier_chain_register(&dca_provider_chain, nb);
	435	}
	436	EXPORT_SYMBOL_GPL(dca_register_notify);
	437
	438	/**
	439	* dca_unregister_notify - remove a client's notifier callback
	440	*/
	441	void dca_unregister_notify(struct notifier_block *nb)
	442	{
	443	blocking_notifier_chain_unregister(&dca_provider_chain, nb);
	444	}
	445	EXPORT_SYMBOL_GPL(dca_unregister_notify);
	446
	447	static int __init dca_init(void)
	448	{
084dac53	449	pr_info("dca service started, version %s\n", DCA_VERSION);
7589670f SN	450	return dca_sysfs_init();
	451	}
	452
	453	static void __exit dca_exit(void)
	454	{
	455	dca_sysfs_exit();
	456	}
	457
652afc27	458	arch_initcall(dca_init);
7589670f SN	459	module_exit(dca_exit);
7589670f SN	460