kernel/irq/msi.c - kernel/msm-4.19 - Gitiles

 /*
  * linux/kernel/irq/msi.c
  *
  * Copyright (C) 2014 Intel Corp.
  * Author: Jiang Liu <jiang.liu@linux.intel.com>
  *
  * This file is licensed under GPLv2.
  *
  * This file contains common code to support Message Signalled Interrupt for
  * PCI compatible and non PCI compatible devices.
  */
 #include <linux/types.h>
 #include <linux/device.h>
 #include <linux/irq.h>
 #include <linux/irqdomain.h>
 #include <linux/msi.h>
 #include <linux/slab.h>

 #include "internals.h"

 /**
  * alloc_msi_entry - Allocate an initialize msi_entry
  * @dev:	Pointer to the device for which this is allocated
  * @nvec:	The number of vectors used in this entry
  * @affinity:	Optional pointer to an affinity mask array size of @nvec
  *
  * If @affinity is not NULL then a an affinity array[@nvec] is allocated
  * and the affinity masks from @affinity are copied.
  */
 struct msi_desc *
 alloc_msi_entry(struct device *dev, int nvec, const struct cpumask *affinity)
 {
 	struct msi_desc *desc;

 	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
 	if (!desc)
 		return NULL;

 	INIT_LIST_HEAD(&desc->list);
 	desc->dev = dev;
 	desc->nvec_used = nvec;
 	if (affinity) {
 		desc->affinity = kmemdup(affinity,
 			nvec * sizeof(*desc->affinity), GFP_KERNEL);
 		if (!desc->affinity) {
 			kfree(desc);
 			return NULL;
 		}
 	}

 	return desc;
 }

 void free_msi_entry(struct msi_desc *entry)
 {
 	kfree(entry->affinity);
 	kfree(entry);
 }

 void __get_cached_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
 {
 	*msg = entry->msg;
 }

 void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg)
 {
 	struct msi_desc *entry = irq_get_msi_desc(irq);

 	__get_cached_msi_msg(entry, msg);
 }
 EXPORT_SYMBOL_GPL(get_cached_msi_msg);

 #ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
 static inline void irq_chip_write_msi_msg(struct irq_data *data,
 					  struct msi_msg *msg)
 {
 	data->chip->irq_write_msi_msg(data, msg);
 }

 /**
  * msi_domain_set_affinity - Generic affinity setter function for MSI domains
  * @irq_data:	The irq data associated to the interrupt
  * @mask:	The affinity mask to set
  * @force:	Flag to enforce setting (disable online checks)
  *
  * Intended to be used by MSI interrupt controllers which are
  * implemented with hierarchical domains.
  */
 int msi_domain_set_affinity(struct irq_data *irq_data,
 			    const struct cpumask *mask, bool force)
 {
 	struct irq_data *parent = irq_data->parent_data;
 	struct msi_msg msg;
 	int ret;

 	ret = parent->chip->irq_set_affinity(parent, mask, force);
 	if (ret >= 0 && ret != IRQ_SET_MASK_OK_DONE) {
 		BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg));
 		irq_chip_write_msi_msg(irq_data, &msg);
 	}

 	return ret;
 }

 static int msi_domain_activate(struct irq_domain *domain,
 			       struct irq_data *irq_data, bool early)
 {
 	struct msi_msg msg;

 	BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg));
 	irq_chip_write_msi_msg(irq_data, &msg);
 	return 0;
 }

 static void msi_domain_deactivate(struct irq_domain *domain,
 				  struct irq_data *irq_data)
 {
 	struct msi_msg msg;

 	memset(&msg, 0, sizeof(msg));
 	irq_chip_write_msi_msg(irq_data, &msg);
 }

 static int msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
 			    unsigned int nr_irqs, void *arg)
 {
 	struct msi_domain_info *info = domain->host_data;
 	struct msi_domain_ops *ops = info->ops;
 	irq_hw_number_t hwirq = ops->get_hwirq(info, arg);
 	int i, ret;

 	if (irq_find_mapping(domain, hwirq) > 0)
 		return -EEXIST;

 	if (domain->parent) {
 		ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
 		if (ret < 0)
 			return ret;
 	}

 	for (i = 0; i < nr_irqs; i++) {
 		ret = ops->msi_init(domain, info, virq + i, hwirq + i, arg);
 		if (ret < 0) {
 			if (ops->msi_free) {
 				for (i--; i > 0; i--)
 					ops->msi_free(domain, info, virq + i);
 			}
 			irq_domain_free_irqs_top(domain, virq, nr_irqs);
 			return ret;
 		}
 	}

 	return 0;
 }

 static void msi_domain_free(struct irq_domain *domain, unsigned int virq,
 			    unsigned int nr_irqs)
 {
 	struct msi_domain_info *info = domain->host_data;
 	int i;

 	if (info->ops->msi_free) {
 		for (i = 0; i < nr_irqs; i++)
 			info->ops->msi_free(domain, info, virq + i);
 	}
 	irq_domain_free_irqs_top(domain, virq, nr_irqs);
 }

 static const struct irq_domain_ops msi_domain_ops = {
 	.alloc		= msi_domain_alloc,
 	.free		= msi_domain_free,
 	.activate	= msi_domain_activate,
 	.deactivate	= msi_domain_deactivate,
 };

 #ifdef GENERIC_MSI_DOMAIN_OPS
 static irq_hw_number_t msi_domain_ops_get_hwirq(struct msi_domain_info *info,
 						msi_alloc_info_t *arg)
 {
 	return arg->hwirq;
 }

 static int msi_domain_ops_prepare(struct irq_domain *domain, struct device *dev,
 				  int nvec, msi_alloc_info_t *arg)
 {
 	memset(arg, 0, sizeof(*arg));
 	return 0;
 }

 static void msi_domain_ops_set_desc(msi_alloc_info_t *arg,
 				    struct msi_desc *desc)
 {
 	arg->desc = desc;
 }
 #else
 #define msi_domain_ops_get_hwirq	NULL
 #define msi_domain_ops_prepare		NULL
 #define msi_domain_ops_set_desc		NULL
 #endif /* !GENERIC_MSI_DOMAIN_OPS */

 static int msi_domain_ops_init(struct irq_domain *domain,
 			       struct msi_domain_info *info,
 			       unsigned int virq, irq_hw_number_t hwirq,
 			       msi_alloc_info_t *arg)
 {
 	irq_domain_set_hwirq_and_chip(domain, virq, hwirq, info->chip,
 				      info->chip_data);
 	if (info->handler && info->handler_name) {
 		__irq_set_handler(virq, info->handler, 0, info->handler_name);
 		if (info->handler_data)
 			irq_set_handler_data(virq, info->handler_data);
 	}
 	return 0;
 }

 static int msi_domain_ops_check(struct irq_domain *domain,
 				struct msi_domain_info *info,
 				struct device *dev)
 {
 	return 0;
 }

 static struct msi_domain_ops msi_domain_ops_default = {
 	.get_hwirq	= msi_domain_ops_get_hwirq,
 	.msi_init	= msi_domain_ops_init,
 	.msi_check	= msi_domain_ops_check,
 	.msi_prepare	= msi_domain_ops_prepare,
 	.set_desc	= msi_domain_ops_set_desc,
 };

 static void msi_domain_update_dom_ops(struct msi_domain_info *info)
 {
 	struct msi_domain_ops *ops = info->ops;

 	if (ops == NULL) {
 		info->ops = &msi_domain_ops_default;
 		return;
 	}

 	if (ops->get_hwirq == NULL)
 		ops->get_hwirq = msi_domain_ops_default.get_hwirq;
 	if (ops->msi_init == NULL)
 		ops->msi_init = msi_domain_ops_default.msi_init;
 	if (ops->msi_check == NULL)
 		ops->msi_check = msi_domain_ops_default.msi_check;
 	if (ops->msi_prepare == NULL)
 		ops->msi_prepare = msi_domain_ops_default.msi_prepare;
 	if (ops->set_desc == NULL)
 		ops->set_desc = msi_domain_ops_default.set_desc;
 }

 static void msi_domain_update_chip_ops(struct msi_domain_info *info)
 {
 	struct irq_chip *chip = info->chip;

 	BUG_ON(!chip || !chip->irq_mask || !chip->irq_unmask);
 	if (!chip->irq_set_affinity)
 		chip->irq_set_affinity = msi_domain_set_affinity;
 }

 /**
  * msi_create_irq_domain - Create a MSI interrupt domain
  * @fwnode:	Optional fwnode of the interrupt controller
  * @info:	MSI domain info
  * @parent:	Parent irq domain
  */
 struct irq_domain *msi_create_irq_domain(struct fwnode_handle *fwnode,
 					 struct msi_domain_info *info,
 					 struct irq_domain *parent)
 {
 	struct irq_domain *domain;

 	if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
 		msi_domain_update_dom_ops(info);
 	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
 		msi_domain_update_chip_ops(info);

 	domain = irq_domain_create_hierarchy(parent, IRQ_DOMAIN_FLAG_MSI, 0,
 					     fwnode, &msi_domain_ops, info);

 	if (domain && !domain->name && info->chip)
 		domain->name = info->chip->name;

 	return domain;
 }

 int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev,
 			    int nvec, msi_alloc_info_t *arg)
 {
 	struct msi_domain_info *info = domain->host_data;
 	struct msi_domain_ops *ops = info->ops;
 	int ret;

 	ret = ops->msi_check(domain, info, dev);
 	if (ret == 0)
 		ret = ops->msi_prepare(domain, dev, nvec, arg);

 	return ret;
 }

 int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev,
 			     int virq, int nvec, msi_alloc_info_t *arg)
 {
 	struct msi_domain_info *info = domain->host_data;
 	struct msi_domain_ops *ops = info->ops;
 	struct msi_desc *desc;
 	int ret = 0;

 	for_each_msi_entry(desc, dev) {
 		/* Don't even try the multi-MSI brain damage. */
 		if (WARN_ON(!desc->irq || desc->nvec_used != 1)) {
 			ret = -EINVAL;
 			break;
 		}

 		if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
 			continue;

 		ops->set_desc(arg, desc);
 		/* Assumes the domain mutex is held! */
 		ret = irq_domain_alloc_irqs_hierarchy(domain, desc->irq, 1,
 						      arg);
 		if (ret)
 			break;

 		irq_set_msi_desc_off(desc->irq, 0, desc);
 	}

 	if (ret) {
 		/* Mop up the damage */
 		for_each_msi_entry(desc, dev) {
 			if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
 				continue;

 			irq_domain_free_irqs_common(domain, desc->irq, 1);
 		}
 	}

 	return ret;
 }

 /**
  * msi_domain_alloc_irqs - Allocate interrupts from a MSI interrupt domain
  * @domain:	The domain to allocate from
  * @dev:	Pointer to device struct of the device for which the interrupts
  *		are allocated
  * @nvec:	The number of interrupts to allocate
  *
  * Returns 0 on success or an error code.
  */
 int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
 			  int nvec)
 {
 	struct msi_domain_info *info = domain->host_data;
 	struct msi_domain_ops *ops = info->ops;
 	msi_alloc_info_t arg;
 	struct msi_desc *desc;
 	int i, ret, virq;

 	ret = msi_domain_prepare_irqs(domain, dev, nvec, &arg);
 	if (ret)
 		return ret;

 	for_each_msi_entry(desc, dev) {
 		ops->set_desc(&arg, desc);

 		virq = __irq_domain_alloc_irqs(domain, -1, desc->nvec_used,
 					       dev_to_node(dev), &arg, false,
 					       desc->affinity);
 		if (virq < 0) {
 			ret = -ENOSPC;
 			if (ops->handle_error)
 				ret = ops->handle_error(domain, desc, ret);
 			if (ops->msi_finish)
 				ops->msi_finish(&arg, ret);
 			return ret;
 		}

 		for (i = 0; i < desc->nvec_used; i++) {
 			irq_set_msi_desc_off(virq, i, desc);
 			irq_debugfs_copy_devname(virq + i, dev);
 		}
 	}

 	if (ops->msi_finish)
 		ops->msi_finish(&arg, 0);

 	for_each_msi_entry(desc, dev) {
 		virq = desc->irq;
 		if (desc->nvec_used == 1)
 			dev_dbg(dev, "irq %d for MSI\n", virq);
 		else
 			dev_dbg(dev, "irq [%d-%d] for MSI\n",
 				virq, virq + desc->nvec_used - 1);
 		/*
 		 * This flag is set by the PCI layer as we need to activate
 		 * the MSI entries before the PCI layer enables MSI in the
 		 * card. Otherwise the card latches a random msi message.
 		 */
 		if (info->flags & MSI_FLAG_ACTIVATE_EARLY) {
 			struct irq_data *irq_data;

 			irq_data = irq_domain_get_irq_data(domain, desc->irq);
 			irq_domain_activate_irq(irq_data);
 		}
 	}

 	return 0;
 }

 /**
  * msi_domain_free_irqs - Free interrupts from a MSI interrupt @domain associated tp @dev
  * @domain:	The domain to managing the interrupts
  * @dev:	Pointer to device struct of the device for which the interrupts
  *		are free
  */
 void msi_domain_free_irqs(struct irq_domain *domain, struct device *dev)
 {
 	struct msi_desc *desc;

 	for_each_msi_entry(desc, dev) {
 		/*
 		 * We might have failed to allocate an MSI early
 		 * enough that there is no IRQ associated to this
 		 * entry. If that's the case, don't do anything.
 		 */
 		if (desc->irq) {
 			irq_domain_free_irqs(desc->irq, desc->nvec_used);
 			desc->irq = 0;
 		}
 	}
 }

 /**
  * msi_get_domain_info - Get the MSI interrupt domain info for @domain
  * @domain:	The interrupt domain to retrieve data from
  *
  * Returns the pointer to the msi_domain_info stored in
  * @domain->host_data.
  */
 struct msi_domain_info *msi_get_domain_info(struct irq_domain *domain)
 {
 	return (struct msi_domain_info *)domain->host_data;
 }

 #endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */
	/*
	* linux/kernel/irq/msi.c
	*
	* Copyright (C) 2014 Intel Corp.
	* Author: Jiang Liu <jiang.liu@linux.intel.com>
	*
	* This file is licensed under GPLv2.
	*
	* This file contains common code to support Message Signalled Interrupt for
	* PCI compatible and non PCI compatible devices.
	*/
	#include <linux/types.h>
	#include <linux/device.h>
	#include <linux/irq.h>
	#include <linux/irqdomain.h>
	#include <linux/msi.h>
	#include <linux/slab.h>

	#include "internals.h"

	/**
	* alloc_msi_entry - Allocate an initialize msi_entry
	* @dev: Pointer to the device for which this is allocated
	* @nvec: The number of vectors used in this entry
	* @affinity: Optional pointer to an affinity mask array size of @nvec
	*
	* If @affinity is not NULL then a an affinity array[@nvec] is allocated
	* and the affinity masks from @affinity are copied.
	*/
	struct msi_desc *
	alloc_msi_entry(struct device dev, int nvec, const struct cpumask affinity)
	{
	struct msi_desc *desc;

	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
	if (!desc)
	return NULL;

	INIT_LIST_HEAD(&desc->list);
	desc->dev = dev;
	desc->nvec_used = nvec;
	if (affinity) {
	desc->affinity = kmemdup(affinity,
	nvec * sizeof(*desc->affinity), GFP_KERNEL);
	if (!desc->affinity) {
	kfree(desc);
	return NULL;
	}
	}

	return desc;
	}

	void free_msi_entry(struct msi_desc *entry)
	{
	kfree(entry->affinity);
	kfree(entry);
	}

	void __get_cached_msi_msg(struct msi_desc entry, struct msi_msg msg)
	{
	*msg = entry->msg;
	}

	void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg)
	{
	struct msi_desc *entry = irq_get_msi_desc(irq);

	__get_cached_msi_msg(entry, msg);
	}
	EXPORT_SYMBOL_GPL(get_cached_msi_msg);

	#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
	static inline void irq_chip_write_msi_msg(struct irq_data *data,
	struct msi_msg *msg)
	{
	data->chip->irq_write_msi_msg(data, msg);
	}

	/**
	* msi_domain_set_affinity - Generic affinity setter function for MSI domains
	* @irq_data: The irq data associated to the interrupt
	* @mask: The affinity mask to set
	* @force: Flag to enforce setting (disable online checks)
	*
	* Intended to be used by MSI interrupt controllers which are
	* implemented with hierarchical domains.
	*/
	int msi_domain_set_affinity(struct irq_data *irq_data,
	const struct cpumask *mask, bool force)
	{
	struct irq_data *parent = irq_data->parent_data;
	struct msi_msg msg;
	int ret;

	ret = parent->chip->irq_set_affinity(parent, mask, force);
	if (ret >= 0 && ret != IRQ_SET_MASK_OK_DONE) {
	BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg));
	irq_chip_write_msi_msg(irq_data, &msg);
	}

	return ret;
	}

	static int msi_domain_activate(struct irq_domain *domain,
	struct irq_data *irq_data, bool early)
	{
	struct msi_msg msg;

	BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg));
	irq_chip_write_msi_msg(irq_data, &msg);
	return 0;
	}

	static void msi_domain_deactivate(struct irq_domain *domain,
	struct irq_data *irq_data)
	{
	struct msi_msg msg;

	memset(&msg, 0, sizeof(msg));
	irq_chip_write_msi_msg(irq_data, &msg);
	}

	static int msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
	unsigned int nr_irqs, void *arg)
	{
	struct msi_domain_info *info = domain->host_data;
	struct msi_domain_ops *ops = info->ops;
	irq_hw_number_t hwirq = ops->get_hwirq(info, arg);
	int i, ret;

	if (irq_find_mapping(domain, hwirq) > 0)
	return -EEXIST;

	if (domain->parent) {
	ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
	if (ret < 0)
	return ret;
	}

	for (i = 0; i < nr_irqs; i++) {
	ret = ops->msi_init(domain, info, virq + i, hwirq + i, arg);
	if (ret < 0) {
	if (ops->msi_free) {
	for (i--; i > 0; i--)
	ops->msi_free(domain, info, virq + i);
	}
	irq_domain_free_irqs_top(domain, virq, nr_irqs);
	return ret;
	}
	}

	return 0;
	}

	static void msi_domain_free(struct irq_domain *domain, unsigned int virq,
	unsigned int nr_irqs)
	{
	struct msi_domain_info *info = domain->host_data;
	int i;

	if (info->ops->msi_free) {
	for (i = 0; i < nr_irqs; i++)
	info->ops->msi_free(domain, info, virq + i);
	}
	irq_domain_free_irqs_top(domain, virq, nr_irqs);
	}

	static const struct irq_domain_ops msi_domain_ops = {
	.alloc = msi_domain_alloc,
	.free = msi_domain_free,
	.activate = msi_domain_activate,
	.deactivate = msi_domain_deactivate,
	};

	#ifdef GENERIC_MSI_DOMAIN_OPS
	static irq_hw_number_t msi_domain_ops_get_hwirq(struct msi_domain_info *info,
	msi_alloc_info_t *arg)
	{
	return arg->hwirq;
	}

	static int msi_domain_ops_prepare(struct irq_domain domain, struct device dev,
	int nvec, msi_alloc_info_t *arg)
	{
	memset(arg, 0, sizeof(*arg));
	return 0;
	}

	static void msi_domain_ops_set_desc(msi_alloc_info_t *arg,
	struct msi_desc *desc)
	{
	arg->desc = desc;
	}
	#else
	#define msi_domain_ops_get_hwirq NULL
	#define msi_domain_ops_prepare NULL
	#define msi_domain_ops_set_desc NULL
	#endif /* !GENERIC_MSI_DOMAIN_OPS */

	static int msi_domain_ops_init(struct irq_domain *domain,
	struct msi_domain_info *info,
	unsigned int virq, irq_hw_number_t hwirq,
	msi_alloc_info_t *arg)
	{
	irq_domain_set_hwirq_and_chip(domain, virq, hwirq, info->chip,
	info->chip_data);
	if (info->handler && info->handler_name) {
	__irq_set_handler(virq, info->handler, 0, info->handler_name);
	if (info->handler_data)
	irq_set_handler_data(virq, info->handler_data);
	}
	return 0;
	}

	static int msi_domain_ops_check(struct irq_domain *domain,
	struct msi_domain_info *info,
	struct device *dev)
	{
	return 0;
	}

	static struct msi_domain_ops msi_domain_ops_default = {
	.get_hwirq = msi_domain_ops_get_hwirq,
	.msi_init = msi_domain_ops_init,
	.msi_check = msi_domain_ops_check,
	.msi_prepare = msi_domain_ops_prepare,
	.set_desc = msi_domain_ops_set_desc,
	};

	static void msi_domain_update_dom_ops(struct msi_domain_info *info)
	{
	struct msi_domain_ops *ops = info->ops;

	if (ops == NULL) {
	info->ops = &msi_domain_ops_default;
	return;
	}

	if (ops->get_hwirq == NULL)
	ops->get_hwirq = msi_domain_ops_default.get_hwirq;
	if (ops->msi_init == NULL)
	ops->msi_init = msi_domain_ops_default.msi_init;
	if (ops->msi_check == NULL)
	ops->msi_check = msi_domain_ops_default.msi_check;
	if (ops->msi_prepare == NULL)
	ops->msi_prepare = msi_domain_ops_default.msi_prepare;
	if (ops->set_desc == NULL)
	ops->set_desc = msi_domain_ops_default.set_desc;
	}

	static void msi_domain_update_chip_ops(struct msi_domain_info *info)
	{
	struct irq_chip *chip = info->chip;

	BUG_ON(!chip \|\| !chip->irq_mask \|\| !chip->irq_unmask);
	if (!chip->irq_set_affinity)
	chip->irq_set_affinity = msi_domain_set_affinity;
	}

	/**
	* msi_create_irq_domain - Create a MSI interrupt domain
	* @fwnode: Optional fwnode of the interrupt controller
	* @info: MSI domain info
	* @parent: Parent irq domain
	*/
	struct irq_domain msi_create_irq_domain(struct fwnode_handle fwnode,
	struct msi_domain_info *info,
	struct irq_domain *parent)
	{
	struct irq_domain *domain;

	if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
	msi_domain_update_dom_ops(info);
	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
	msi_domain_update_chip_ops(info);

	domain = irq_domain_create_hierarchy(parent, IRQ_DOMAIN_FLAG_MSI, 0,
	fwnode, &msi_domain_ops, info);

	if (domain && !domain->name && info->chip)
	domain->name = info->chip->name;

	return domain;
	}

	int msi_domain_prepare_irqs(struct irq_domain domain, struct device dev,
	int nvec, msi_alloc_info_t *arg)
	{
	struct msi_domain_info *info = domain->host_data;
	struct msi_domain_ops *ops = info->ops;
	int ret;

	ret = ops->msi_check(domain, info, dev);
	if (ret == 0)
	ret = ops->msi_prepare(domain, dev, nvec, arg);

	return ret;
	}

	int msi_domain_populate_irqs(struct irq_domain domain, struct device dev,
	int virq, int nvec, msi_alloc_info_t *arg)
	{
	struct msi_domain_info *info = domain->host_data;
	struct msi_domain_ops *ops = info->ops;
	struct msi_desc *desc;
	int ret = 0;

	for_each_msi_entry(desc, dev) {
	/* Don't even try the multi-MSI brain damage. */
	if (WARN_ON(!desc->irq \|\| desc->nvec_used != 1)) {
	ret = -EINVAL;
	break;
	}

	if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
	continue;

	ops->set_desc(arg, desc);
	/* Assumes the domain mutex is held! */
	ret = irq_domain_alloc_irqs_hierarchy(domain, desc->irq, 1,
	arg);
	if (ret)
	break;

	irq_set_msi_desc_off(desc->irq, 0, desc);
	}

	if (ret) {
	/* Mop up the damage */
	for_each_msi_entry(desc, dev) {
	if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
	continue;

	irq_domain_free_irqs_common(domain, desc->irq, 1);
	}
	}

	return ret;
	}

	/**
	* msi_domain_alloc_irqs - Allocate interrupts from a MSI interrupt domain
	* @domain: The domain to allocate from
	* @dev: Pointer to device struct of the device for which the interrupts
	* are allocated
	* @nvec: The number of interrupts to allocate
	*
	* Returns 0 on success or an error code.
	*/
	int msi_domain_alloc_irqs(struct irq_domain domain, struct device dev,
	int nvec)
	{
	struct msi_domain_info *info = domain->host_data;
	struct msi_domain_ops *ops = info->ops;
	msi_alloc_info_t arg;
	struct msi_desc *desc;
	int i, ret, virq;

	ret = msi_domain_prepare_irqs(domain, dev, nvec, &arg);
	if (ret)
	return ret;

	for_each_msi_entry(desc, dev) {
	ops->set_desc(&arg, desc);

	virq = __irq_domain_alloc_irqs(domain, -1, desc->nvec_used,
	dev_to_node(dev), &arg, false,
	desc->affinity);
	if (virq < 0) {
	ret = -ENOSPC;
	if (ops->handle_error)
	ret = ops->handle_error(domain, desc, ret);
	if (ops->msi_finish)
	ops->msi_finish(&arg, ret);
	return ret;
	}

	for (i = 0; i < desc->nvec_used; i++) {
	irq_set_msi_desc_off(virq, i, desc);
	irq_debugfs_copy_devname(virq + i, dev);
	}
	}

	if (ops->msi_finish)
	ops->msi_finish(&arg, 0);

	for_each_msi_entry(desc, dev) {
	virq = desc->irq;
	if (desc->nvec_used == 1)
	dev_dbg(dev, "irq %d for MSI\n", virq);
	else
	dev_dbg(dev, "irq [%d-%d] for MSI\n",
	virq, virq + desc->nvec_used - 1);
	/*
	* This flag is set by the PCI layer as we need to activate
	* the MSI entries before the PCI layer enables MSI in the
	* card. Otherwise the card latches a random msi message.
	*/
	if (info->flags & MSI_FLAG_ACTIVATE_EARLY) {
	struct irq_data *irq_data;

	irq_data = irq_domain_get_irq_data(domain, desc->irq);
	irq_domain_activate_irq(irq_data);
	}
	}

	return 0;
	}

	/**
	* msi_domain_free_irqs - Free interrupts from a MSI interrupt @domain associated tp @dev
	* @domain: The domain to managing the interrupts
	* @dev: Pointer to device struct of the device for which the interrupts
	* are free
	*/
	void msi_domain_free_irqs(struct irq_domain domain, struct device dev)
	{
	struct msi_desc *desc;

	for_each_msi_entry(desc, dev) {
	/*
	* We might have failed to allocate an MSI early
	* enough that there is no IRQ associated to this
	* entry. If that's the case, don't do anything.
	*/
	if (desc->irq) {
	irq_domain_free_irqs(desc->irq, desc->nvec_used);
	desc->irq = 0;
	}
	}
	}

	/**
	* msi_get_domain_info - Get the MSI interrupt domain info for @domain
	* @domain: The interrupt domain to retrieve data from
	*
	* Returns the pointer to the msi_domain_info stored in
	* @domain->host_data.
	*/
	struct msi_domain_info msi_get_domain_info(struct irq_domain domain)
	{
	return (struct msi_domain_info *)domain->host_data;
	}

	#endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */