[linux.git] / drivers / pci / ats.c

/*
 * drivers/pci/ats.c
 *
 * Copyright (C) 2009 Intel Corporation, Yu Zhao <[email protected]>
 * Copyright (C) 2011 Advanced Micro Devices,
 *
 * PCI Express I/O Virtualization (IOV) support.
 *   Address Translation Service 1.0
 *   Page Request Interface added by Joerg Roedel <[email protected]>
 *   PASID support added by Joerg Roedel <[email protected]>
 */

#include <linux/export.h>
#include <linux/pci-ats.h>
#include <linux/pci.h>
#include <linux/slab.h>

#include "pci.h"

static int ats_alloc_one(struct pci_dev *dev, int ps)
{
	int pos;
	u16 cap;
	struct pci_ats *ats;

	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
	if (!pos)
		return -ENODEV;

	ats = kzalloc(sizeof(*ats), GFP_KERNEL);
	if (!ats)
		return -ENOMEM;

	ats->pos = pos;
	ats->stu = ps;
	pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap);
	ats->qdep = PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) :
					    PCI_ATS_MAX_QDEP;
	dev->ats = ats;

	return 0;
}

static void ats_free_one(struct pci_dev *dev)
{
	kfree(dev->ats);
	dev->ats = NULL;
}

/**
 * pci_enable_ats - enable the ATS capability
 * @dev: the PCI device
 * @ps: the IOMMU page shift
 *
 * Returns 0 on success, or negative on failure.
 */
int pci_enable_ats(struct pci_dev *dev, int ps)
{
	int rc;
	u16 ctrl;

	BUG_ON(dev->ats && dev->ats->is_enabled);

	if (ps < PCI_ATS_MIN_STU)
		return -EINVAL;

	if (dev->is_physfn || dev->is_virtfn) {
		struct pci_dev *pdev = dev->is_physfn ? dev : dev->physfn;

		mutex_lock(&pdev->sriov->lock);
		if (pdev->ats)
			rc = pdev->ats->stu == ps ? 0 : -EINVAL;
		else
			rc = ats_alloc_one(pdev, ps);

		if (!rc)
			pdev->ats->ref_cnt++;
		mutex_unlock(&pdev->sriov->lock);
		if (rc)
			return rc;
	}

	if (!dev->is_physfn) {
		rc = ats_alloc_one(dev, ps);
		if (rc)
			return rc;
	}

	ctrl = PCI_ATS_CTRL_ENABLE;
	if (!dev->is_virtfn)
		ctrl |= PCI_ATS_CTRL_STU(ps - PCI_ATS_MIN_STU);
	pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);

	dev->ats->is_enabled = 1;

	return 0;
}
EXPORT_SYMBOL_GPL(pci_enable_ats);

/**
 * pci_disable_ats - disable the ATS capability
 * @dev: the PCI device
 */
void pci_disable_ats(struct pci_dev *dev)
{
	u16 ctrl;

	BUG_ON(!dev->ats || !dev->ats->is_enabled);

	pci_read_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, &ctrl);
	ctrl &= ~PCI_ATS_CTRL_ENABLE;
	pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);

	dev->ats->is_enabled = 0;

	if (dev->is_physfn || dev->is_virtfn) {
		struct pci_dev *pdev = dev->is_physfn ? dev : dev->physfn;

		mutex_lock(&pdev->sriov->lock);
		pdev->ats->ref_cnt--;
		if (!pdev->ats->ref_cnt)
			ats_free_one(pdev);
		mutex_unlock(&pdev->sriov->lock);
	}

	if (!dev->is_physfn)
		ats_free_one(dev);
}
EXPORT_SYMBOL_GPL(pci_disable_ats);

void pci_restore_ats_state(struct pci_dev *dev)
{
	u16 ctrl;

	if (!pci_ats_enabled(dev))
		return;
	if (!pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS))
		BUG();

	ctrl = PCI_ATS_CTRL_ENABLE;
	if (!dev->is_virtfn)
		ctrl |= PCI_ATS_CTRL_STU(dev->ats->stu - PCI_ATS_MIN_STU);

	pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);
}
EXPORT_SYMBOL_GPL(pci_restore_ats_state);

/**
 * pci_ats_queue_depth - query the ATS Invalidate Queue Depth
 * @dev: the PCI device
 *
 * Returns the queue depth on success, or negative on failure.
 *
 * The ATS spec uses 0 in the Invalidate Queue Depth field to
 * indicate that the function can accept 32 Invalidate Request.
 * But here we use the `real' values (i.e. 1~32) for the Queue
 * Depth; and 0 indicates the function shares the Queue with
 * other functions (doesn't exclusively own a Queue).
 */
int pci_ats_queue_depth(struct pci_dev *dev)
{
	int pos;
	u16 cap;

	if (dev->is_virtfn)
		return 0;

	if (dev->ats)
		return dev->ats->qdep;

	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
	if (!pos)
		return -ENODEV;

	pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap);

	return PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) :
				       PCI_ATS_MAX_QDEP;
}
EXPORT_SYMBOL_GPL(pci_ats_queue_depth);

#ifdef CONFIG_PCI_PRI
/**
 * pci_enable_pri - Enable PRI capability
 * @ pdev: PCI device structure
 *
 * Returns 0 on success, negative value on error
 */
int pci_enable_pri(struct pci_dev *pdev, u32 reqs)
{
	u16 control, status;
	u32 max_requests;
	int pos;

	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
	if (!pos)
		return -EINVAL;

	pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
	pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
	if ((control & PCI_PRI_CTRL_ENABLE) ||
	    !(status & PCI_PRI_STATUS_STOPPED))
		return -EBUSY;

	pci_read_config_dword(pdev, pos + PCI_PRI_MAX_REQ, &max_requests);
	reqs = min(max_requests, reqs);
	pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ, reqs);

	control |= PCI_PRI_CTRL_ENABLE;
	pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);

	return 0;
}
EXPORT_SYMBOL_GPL(pci_enable_pri);

/**
 * pci_disable_pri - Disable PRI capability
 * @pdev: PCI device structure
 *
 * Only clears the enabled-bit, regardless of its former value
 */
void pci_disable_pri(struct pci_dev *pdev)
{
	u16 control;
	int pos;

	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
	if (!pos)
		return;

	pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
	control &= ~PCI_PRI_CTRL_ENABLE;
	pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
}
EXPORT_SYMBOL_GPL(pci_disable_pri);

/**
 * pci_reset_pri - Resets device's PRI state
 * @pdev: PCI device structure
 *
 * The PRI capability must be disabled before this function is called.
 * Returns 0 on success, negative value on error.
 */
int pci_reset_pri(struct pci_dev *pdev)
{
	u16 control;
	int pos;

	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
	if (!pos)
		return -EINVAL;

	pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
	if (control & PCI_PRI_CTRL_ENABLE)
		return -EBUSY;

	control |= PCI_PRI_CTRL_RESET;

	pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);

	return 0;
}
EXPORT_SYMBOL_GPL(pci_reset_pri);
#endif /* CONFIG_PCI_PRI */

#ifdef CONFIG_PCI_PASID
/**
 * pci_enable_pasid - Enable the PASID capability
 * @pdev: PCI device structure
 * @features: Features to enable
 *
 * Returns 0 on success, negative value on error. This function checks
 * whether the features are actually supported by the device and returns
 * an error if not.
 */
int pci_enable_pasid(struct pci_dev *pdev, int features)
{
	u16 control, supported;
	int pos;

	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
	if (!pos)
		return -EINVAL;

	pci_read_config_word(pdev, pos + PCI_PASID_CTRL, &control);
	pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);

	if (control & PCI_PASID_CTRL_ENABLE)
		return -EINVAL;

	supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV;

	/* User wants to enable anything unsupported? */
	if ((supported & features) != features)
		return -EINVAL;

	control = PCI_PASID_CTRL_ENABLE | features;

	pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);

	return 0;
}
EXPORT_SYMBOL_GPL(pci_enable_pasid);

/**
 * pci_disable_pasid - Disable the PASID capability
 * @pdev: PCI device structure
 *
 */
void pci_disable_pasid(struct pci_dev *pdev)
{
	u16 control = 0;
	int pos;

	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
	if (!pos)
		return;

	pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
}
EXPORT_SYMBOL_GPL(pci_disable_pasid);

/**
 * pci_pasid_features - Check which PASID features are supported
 * @pdev: PCI device structure
 *
 * Returns a negative value when no PASI capability is present.
 * Otherwise is returns a bitmask with supported features. Current
 * features reported are:
 * PCI_PASID_CAP_EXEC - Execute permission supported
 * PCI_PASID_CAP_PRIV - Privileged mode supported
 */
int pci_pasid_features(struct pci_dev *pdev)
{
	u16 supported;
	int pos;

	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
	if (!pos)
		return -EINVAL;

	pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);

	supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV;

	return supported;
}
EXPORT_SYMBOL_GPL(pci_pasid_features);

#define PASID_NUMBER_SHIFT	8
#define PASID_NUMBER_MASK	(0x1f << PASID_NUMBER_SHIFT)
/**
 * pci_max_pasid - Get maximum number of PASIDs supported by device
 * @pdev: PCI device structure
 *
 * Returns negative value when PASID capability is not present.
 * Otherwise it returns the numer of supported PASIDs.
 */
int pci_max_pasids(struct pci_dev *pdev)
{
	u16 supported;
	int pos;

	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
	if (!pos)
		return -EINVAL;

	pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);

	supported = (supported & PASID_NUMBER_MASK) >> PASID_NUMBER_SHIFT;

	return (1 << supported);
}
EXPORT_SYMBOL_GPL(pci_max_pasids);
#endif /* CONFIG_PCI_PASID */
Commit	Line	Data
db3c33c6 JR	1	/*
	2	* drivers/pci/ats.c
	3	*
	4	* Copyright (C) 2009 Intel Corporation, Yu Zhao <[email protected]>
c320b976	5	* Copyright (C) 2011 Advanced Micro Devices,
db3c33c6 JR	6	*
	7	* PCI Express I/O Virtualization (IOV) support.
	8	* Address Translation Service 1.0
c320b976	9	* Page Request Interface added by Joerg Roedel <[email protected]>
086ac11f	10	* PASID support added by Joerg Roedel <[email protected]>
db3c33c6 JR	11	*/
db3c33c6 JR	12
363c75db	13	#include <linux/export.h>
db3c33c6 JR	14	#include <linux/pci-ats.h>
db3c33c6 JR	15	#include <linux/pci.h>
8c451945	16	#include <linux/slab.h>
db3c33c6 JR	17
	18	#include "pci.h"
	19
	20	static int ats_alloc_one(struct pci_dev *dev, int ps)
	21	{
	22	int pos;
	23	u16 cap;
	24	struct pci_ats *ats;
	25
	26	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
	27	if (!pos)
	28	return -ENODEV;
	29
	30	ats = kzalloc(sizeof(*ats), GFP_KERNEL);
	31	if (!ats)
	32	return -ENOMEM;
	33
	34	ats->pos = pos;
	35	ats->stu = ps;
	36	pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap);
	37	ats->qdep = PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) :
	38	PCI_ATS_MAX_QDEP;
	39	dev->ats = ats;
	40
	41	return 0;
	42	}
	43
	44	static void ats_free_one(struct pci_dev *dev)
	45	{
	46	kfree(dev->ats);
	47	dev->ats = NULL;
	48	}
	49
	50	/**
	51	* pci_enable_ats - enable the ATS capability
	52	* @dev: the PCI device
	53	* @ps: the IOMMU page shift
	54	*
	55	* Returns 0 on success, or negative on failure.
	56	*/
	57	int pci_enable_ats(struct pci_dev *dev, int ps)
	58	{
	59	int rc;
	60	u16 ctrl;
	61
	62	BUG_ON(dev->ats && dev->ats->is_enabled);
	63
	64	if (ps < PCI_ATS_MIN_STU)
	65	return -EINVAL;
	66
	67	if (dev->is_physfn \|\| dev->is_virtfn) {
	68	struct pci_dev *pdev = dev->is_physfn ? dev : dev->physfn;
	69
	70	mutex_lock(&pdev->sriov->lock);
	71	if (pdev->ats)
	72	rc = pdev->ats->stu == ps ? 0 : -EINVAL;
	73	else
	74	rc = ats_alloc_one(pdev, ps);
	75
	76	if (!rc)
	77	pdev->ats->ref_cnt++;
	78	mutex_unlock(&pdev->sriov->lock);
	79	if (rc)
	80	return rc;
81	}
82
83	if (!dev->is_physfn) {
84	rc = ats_alloc_one(dev, ps);
85	if (rc)
86	return rc;
87	}
88
89	ctrl = PCI_ATS_CTRL_ENABLE;
90	if (!dev->is_virtfn)
91	ctrl \|= PCI_ATS_CTRL_STU(ps - PCI_ATS_MIN_STU);
92	pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);
93
94	dev->ats->is_enabled = 1;
95
96	return 0;
97	}
d4c0636c	98	EXPORT_SYMBOL_GPL(pci_enable_ats);
db3c33c6 JR	99
	100	/**
	101	* pci_disable_ats - disable the ATS capability
	102	* @dev: the PCI device
	103	*/
	104	void pci_disable_ats(struct pci_dev *dev)
	105	{
	106	u16 ctrl;
	107
	108	BUG_ON(!dev->ats \|\| !dev->ats->is_enabled);
	109
	110	pci_read_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, &ctrl);
	111	ctrl &= ~PCI_ATS_CTRL_ENABLE;
	112	pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);
	113
	114	dev->ats->is_enabled = 0;
	115
	116	if (dev->is_physfn \|\| dev->is_virtfn) {
	117	struct pci_dev *pdev = dev->is_physfn ? dev : dev->physfn;
	118
	119	mutex_lock(&pdev->sriov->lock);
	120	pdev->ats->ref_cnt--;
	121	if (!pdev->ats->ref_cnt)
	122	ats_free_one(pdev);
	123	mutex_unlock(&pdev->sriov->lock);
	124	}
	125
	126	if (!dev->is_physfn)
	127	ats_free_one(dev);
	128	}
d4c0636c	129	EXPORT_SYMBOL_GPL(pci_disable_ats);
db3c33c6	130
1900ca13 HX	131	void pci_restore_ats_state(struct pci_dev *dev)
	132	{
	133	u16 ctrl;
	134
	135	if (!pci_ats_enabled(dev))
	136	return;
	137	if (!pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS))
	138	BUG();
	139
	140	ctrl = PCI_ATS_CTRL_ENABLE;
	141	if (!dev->is_virtfn)
	142	ctrl \|= PCI_ATS_CTRL_STU(dev->ats->stu - PCI_ATS_MIN_STU);
	143
	144	pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);
	145	}
	146	EXPORT_SYMBOL_GPL(pci_restore_ats_state);
	147
db3c33c6 JR	148	/**
	149	* pci_ats_queue_depth - query the ATS Invalidate Queue Depth
	150	* @dev: the PCI device
	151	*
	152	* Returns the queue depth on success, or negative on failure.
	153	*
	154	* The ATS spec uses 0 in the Invalidate Queue Depth field to
	155	* indicate that the function can accept 32 Invalidate Request.
	156	* But here we use the `real' values (i.e. 1~32) for the Queue
	157	* Depth; and 0 indicates the function shares the Queue with
	158	* other functions (doesn't exclusively own a Queue).
	159	*/
	160	int pci_ats_queue_depth(struct pci_dev *dev)
	161	{
	162	int pos;
	163	u16 cap;
	164
	165	if (dev->is_virtfn)
	166	return 0;
	167
	168	if (dev->ats)
	169	return dev->ats->qdep;
	170
	171	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
	172	if (!pos)
	173	return -ENODEV;
	174
	175	pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap);
	176
	177	return PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) :
	178	PCI_ATS_MAX_QDEP;
	179	}
d4c0636c	180	EXPORT_SYMBOL_GPL(pci_ats_queue_depth);
c320b976 JR	181
	182	#ifdef CONFIG_PCI_PRI
	183	/**
	184	* pci_enable_pri - Enable PRI capability
	185	* @ pdev: PCI device structure
	186	*
	187	* Returns 0 on success, negative value on error
	188	*/
	189	int pci_enable_pri(struct pci_dev *pdev, u32 reqs)
	190	{
	191	u16 control, status;
	192	u32 max_requests;
	193	int pos;
	194
69166fbf	195	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
c320b976 JR	196	if (!pos)
	197	return -EINVAL;
	198
91f57d5e AW	199	pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
	200	pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
	201	if ((control & PCI_PRI_CTRL_ENABLE) \|\|
	202	!(status & PCI_PRI_STATUS_STOPPED))
c320b976 JR	203	return -EBUSY;
c320b976 JR	204
91f57d5e	205	pci_read_config_dword(pdev, pos + PCI_PRI_MAX_REQ, &max_requests);
c320b976	206	reqs = min(max_requests, reqs);
91f57d5e	207	pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ, reqs);
c320b976	208
91f57d5e AW	209	control \|= PCI_PRI_CTRL_ENABLE;
91f57d5e AW	210	pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
c320b976 JR	211
	212	return 0;
	213	}
	214	EXPORT_SYMBOL_GPL(pci_enable_pri);
	215
	216	/**
	217	* pci_disable_pri - Disable PRI capability
	218	* @pdev: PCI device structure
	219	*
	220	* Only clears the enabled-bit, regardless of its former value
	221	*/
	222	void pci_disable_pri(struct pci_dev *pdev)
	223	{
	224	u16 control;
	225	int pos;
	226
69166fbf	227	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
c320b976 JR	228	if (!pos)
	229	return;
	230
91f57d5e AW	231	pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
	232	control &= ~PCI_PRI_CTRL_ENABLE;
	233	pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
c320b976 JR	234	}
	235	EXPORT_SYMBOL_GPL(pci_disable_pri);
	236
c320b976 JR	237	/**
	238	* pci_reset_pri - Resets device's PRI state
	239	* @pdev: PCI device structure
	240	*
	241	* The PRI capability must be disabled before this function is called.
	242	* Returns 0 on success, negative value on error.
	243	*/
	244	int pci_reset_pri(struct pci_dev *pdev)
	245	{
	246	u16 control;
	247	int pos;
	248
69166fbf	249	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
c320b976 JR	250	if (!pos)
	251	return -EINVAL;
	252
91f57d5e AW	253	pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
91f57d5e AW	254	if (control & PCI_PRI_CTRL_ENABLE)
c320b976 JR	255	return -EBUSY;
c320b976 JR	256
91f57d5e	257	control \|= PCI_PRI_CTRL_RESET;
c320b976	258
91f57d5e	259	pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
c320b976 JR	260
	261	return 0;
	262	}
	263	EXPORT_SYMBOL_GPL(pci_reset_pri);
c320b976	264	#endif /* CONFIG_PCI_PRI */
086ac11f JR	265
	266	#ifdef CONFIG_PCI_PASID
	267	/**
	268	* pci_enable_pasid - Enable the PASID capability
	269	* @pdev: PCI device structure
	270	* @features: Features to enable
	271	*
	272	* Returns 0 on success, negative value on error. This function checks
	273	* whether the features are actually supported by the device and returns
	274	* an error if not.
	275	*/
	276	int pci_enable_pasid(struct pci_dev *pdev, int features)
	277	{
	278	u16 control, supported;
	279	int pos;
	280
69166fbf	281	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
086ac11f JR	282	if (!pos)
	283	return -EINVAL;
	284
91f57d5e AW	285	pci_read_config_word(pdev, pos + PCI_PASID_CTRL, &control);
91f57d5e AW	286	pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);
086ac11f	287
91f57d5e	288	if (control & PCI_PASID_CTRL_ENABLE)
086ac11f JR	289	return -EINVAL;
086ac11f JR	290
91f57d5e	291	supported &= PCI_PASID_CAP_EXEC \| PCI_PASID_CAP_PRIV;
086ac11f JR	292
	293	/* User wants to enable anything unsupported? */
	294	if ((supported & features) != features)
	295	return -EINVAL;
	296
91f57d5e	297	control = PCI_PASID_CTRL_ENABLE \| features;
086ac11f	298
91f57d5e	299	pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
086ac11f JR	300
	301	return 0;
	302	}
	303	EXPORT_SYMBOL_GPL(pci_enable_pasid);
	304
	305	/**
	306	* pci_disable_pasid - Disable the PASID capability
	307	* @pdev: PCI device structure
	308	*
	309	*/
	310	void pci_disable_pasid(struct pci_dev *pdev)
	311	{
	312	u16 control = 0;
	313	int pos;
	314
69166fbf	315	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
086ac11f JR	316	if (!pos)
	317	return;
	318
91f57d5e	319	pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
086ac11f JR	320	}
	321	EXPORT_SYMBOL_GPL(pci_disable_pasid);
	322
	323	/**
	324	* pci_pasid_features - Check which PASID features are supported
	325	* @pdev: PCI device structure
	326	*
	327	* Returns a negative value when no PASI capability is present.
	328	* Otherwise is returns a bitmask with supported features. Current
	329	* features reported are:
91f57d5e	330	* PCI_PASID_CAP_EXEC - Execute permission supported
f7625980	331	* PCI_PASID_CAP_PRIV - Privileged mode supported
086ac11f JR	332	*/
	333	int pci_pasid_features(struct pci_dev *pdev)
	334	{
	335	u16 supported;
	336	int pos;
	337
69166fbf	338	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
086ac11f JR	339	if (!pos)
	340	return -EINVAL;
	341
91f57d5e	342	pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);
086ac11f	343
91f57d5e	344	supported &= PCI_PASID_CAP_EXEC \| PCI_PASID_CAP_PRIV;
086ac11f JR	345
	346	return supported;
	347	}
	348	EXPORT_SYMBOL_GPL(pci_pasid_features);
	349
	350	#define PASID_NUMBER_SHIFT 8
	351	#define PASID_NUMBER_MASK (0x1f << PASID_NUMBER_SHIFT)
	352	/**
	353	* pci_max_pasid - Get maximum number of PASIDs supported by device
	354	* @pdev: PCI device structure
	355	*
	356	* Returns negative value when PASID capability is not present.
	357	* Otherwise it returns the numer of supported PASIDs.
	358	*/
	359	int pci_max_pasids(struct pci_dev *pdev)
	360	{
	361	u16 supported;
	362	int pos;
	363
69166fbf	364	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
086ac11f JR	365	if (!pos)
	366	return -EINVAL;
	367
91f57d5e	368	pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);
086ac11f JR	369
	370	supported = (supported & PASID_NUMBER_MASK) >> PASID_NUMBER_SHIFT;
	371
	372	return (1 << supported);
	373	}
	374	EXPORT_SYMBOL_GPL(pci_max_pasids);
	375	#endif /* CONFIG_PCI_PASID */