drivers/pci/ats.c - LeafOS-Devices/android_kernel_realme_mt6785 - Gitiles

 /*
  * drivers/pci/ats.c
  *
  * Copyright (C) 2009 Intel Corporation, Yu Zhao <yu.zhao@intel.com>
  * 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 <joerg.roedel@amd.com>
  *   PASID support added by Joerg Roedel <joerg.roedel@amd.com>
  */

 #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);

 /**
  * 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_pri_enabled - Checks if PRI capability is enabled
  * @pdev: PCI device structure
  *
  * Returns true if PRI is enabled on the device, false otherwise
  */
 bool pci_pri_enabled(struct pci_dev *pdev)
 {
 	u16 control;
 	int pos;

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

 	pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);

 	return (control & PCI_PRI_CTRL_ENABLE) ? true : false;
 }
 EXPORT_SYMBOL_GPL(pci_pri_enabled);

 /**
  * 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);

 /**
  * pci_pri_stopped - Checks whether the PRI capability is stopped
  * @pdev: PCI device structure
  *
  * Returns true if the PRI capability on the device is disabled and the
  * device has no outstanding PRI requests, false otherwise. The device
  * indicates this via the STOPPED bit in the status register of the
  * capability.
  * The device internal state can be cleared by resetting the PRI state
  * with pci_reset_pri(). This can force the capability into the STOPPED
  * state.
  */
 bool pci_pri_stopped(struct pci_dev *pdev)
 {
 	u16 control, status;
 	int pos;

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

 	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)
 		return false;

 	return (status & PCI_PRI_STATUS_STOPPED) ? true : false;
 }
 EXPORT_SYMBOL_GPL(pci_pri_stopped);

 /**
  * pci_pri_status - Request PRI status of a device
  * @pdev: PCI device structure
  *
  * Returns negative value on failure, status on success. The status can
  * be checked against status-bits. Supported bits are currently:
  * PCI_PRI_STATUS_RF:      Response failure
  * PCI_PRI_STATUS_UPRGI:   Unexpected Page Request Group Index
  * PCI_PRI_STATUS_STOPPED: PRI has stopped
  */
 int pci_pri_status(struct pci_dev *pdev)
 {
 	u16 status, 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);
 	pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);

 	/* Stopped bit is undefined when enable == 1, so clear it */
 	if (control & PCI_PRI_CTRL_ENABLE)
 		status &= ~PCI_PRI_STATUS_STOPPED;

 	return status;
 }
 EXPORT_SYMBOL_GPL(pci_pri_status);
 #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 - Priviledged 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 */
	/*
	* drivers/pci/ats.c
	*
	* Copyright (C) 2009 Intel Corporation, Yu Zhao <yu.zhao@intel.com>
	* 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 <joerg.roedel@amd.com>
	* PASID support added by Joerg Roedel <joerg.roedel@amd.com>
	*/

	#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);

	/**
	* 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_pri_enabled - Checks if PRI capability is enabled
	* @pdev: PCI device structure
	*
	* Returns true if PRI is enabled on the device, false otherwise
	*/
	bool pci_pri_enabled(struct pci_dev *pdev)
	{
	u16 control;
	int pos;

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

	pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);

	return (control & PCI_PRI_CTRL_ENABLE) ? true : false;
	}
	EXPORT_SYMBOL_GPL(pci_pri_enabled);

	/**
	* 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);

	/**
	* pci_pri_stopped - Checks whether the PRI capability is stopped
	* @pdev: PCI device structure
	*
	* Returns true if the PRI capability on the device is disabled and the
	* device has no outstanding PRI requests, false otherwise. The device
	* indicates this via the STOPPED bit in the status register of the
	* capability.
	* The device internal state can be cleared by resetting the PRI state
	* with pci_reset_pri(). This can force the capability into the STOPPED
	* state.
	*/
	bool pci_pri_stopped(struct pci_dev *pdev)
	{
	u16 control, status;
	int pos;

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

	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)
	return false;

	return (status & PCI_PRI_STATUS_STOPPED) ? true : false;
	}
	EXPORT_SYMBOL_GPL(pci_pri_stopped);

	/**
	* pci_pri_status - Request PRI status of a device
	* @pdev: PCI device structure
	*
	* Returns negative value on failure, status on success. The status can
	* be checked against status-bits. Supported bits are currently:
	* PCI_PRI_STATUS_RF: Response failure
	* PCI_PRI_STATUS_UPRGI: Unexpected Page Request Group Index
	* PCI_PRI_STATUS_STOPPED: PRI has stopped
	*/
	int pci_pri_status(struct pci_dev *pdev)
	{
	u16 status, 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);
	pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);

	/* Stopped bit is undefined when enable == 1, so clear it */
	if (control & PCI_PRI_CTRL_ENABLE)
	status &= ~PCI_PRI_STATUS_STOPPED;

	return status;
	}
	EXPORT_SYMBOL_GPL(pci_pri_status);
	#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 - Priviledged 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 */