drivers/base/platform-msi.c - kernel/msm-4.19 - Gitiles

 /*
  * MSI framework for platform devices
  *
  * Copyright (C) 2015 ARM Limited, All Rights Reserved.
  * Author: Marc Zyngier <marc.zyngier@arm.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * 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, see <http://www.gnu.org/licenses/>.
  */

 #include <linux/device.h>
 #include <linux/idr.h>
 #include <linux/irq.h>
 #include <linux/irqdomain.h>
 #include <linux/msi.h>
 #include <linux/slab.h>

 #define DEV_ID_SHIFT	21
 #define MAX_DEV_MSIS	(1 << (32 - DEV_ID_SHIFT))

 /*
  * Internal data structure containing a (made up, but unique) devid
  * and the callback to write the MSI message.
  */
 struct platform_msi_priv_data {
 	struct device		*dev;
 	void 			*host_data;
 	msi_alloc_info_t	arg;
 	irq_write_msi_msg_t	write_msg;
 	int			devid;
 };

 /* The devid allocator */
 static DEFINE_IDA(platform_msi_devid_ida);

 #ifdef GENERIC_MSI_DOMAIN_OPS
 /*
  * Convert an msi_desc to a globaly unique identifier (per-device
  * devid + msi_desc position in the msi_list).
  */
 static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
 {
 	u32 devid;

 	devid = desc->platform.msi_priv_data->devid;

 	return (devid << (32 - DEV_ID_SHIFT)) | desc->platform.msi_index;
 }

 static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
 {
 	arg->desc = desc;
 	arg->hwirq = platform_msi_calc_hwirq(desc);
 }

 static int platform_msi_init(struct irq_domain *domain,
 			     struct msi_domain_info *info,
 			     unsigned int virq, irq_hw_number_t hwirq,
 			     msi_alloc_info_t *arg)
 {
 	return irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
 					     info->chip, info->chip_data);
 }
 #else
 #define platform_msi_set_desc		NULL
 #define platform_msi_init		NULL
 #endif

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

 	BUG_ON(!ops);

 	if (ops->msi_init == NULL)
 		ops->msi_init = platform_msi_init;
 	if (ops->set_desc == NULL)
 		ops->set_desc = platform_msi_set_desc;
 }

 static void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
 {
 	struct msi_desc *desc = irq_data_get_msi_desc(data);
 	struct platform_msi_priv_data *priv_data;

 	priv_data = desc->platform.msi_priv_data;

 	priv_data->write_msg(desc, msg);
 }

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

 	BUG_ON(!chip);
 	if (!chip->irq_mask)
 		chip->irq_mask = irq_chip_mask_parent;
 	if (!chip->irq_unmask)
 		chip->irq_unmask = irq_chip_unmask_parent;
 	if (!chip->irq_eoi)
 		chip->irq_eoi = irq_chip_eoi_parent;
 	if (!chip->irq_set_affinity)
 		chip->irq_set_affinity = msi_domain_set_affinity;
 	if (!chip->irq_write_msi_msg)
 		chip->irq_write_msi_msg = platform_msi_write_msg;
 }

 static void platform_msi_free_descs(struct device *dev, int base, int nvec)
 {
 	struct msi_desc *desc, *tmp;

 	list_for_each_entry_safe(desc, tmp, dev_to_msi_list(dev), list) {
 		if (desc->platform.msi_index >= base &&
 		    desc->platform.msi_index < (base + nvec)) {
 			list_del(&desc->list);
 			free_msi_entry(desc);
 		}
 	}
 }

 static int platform_msi_alloc_descs_with_irq(struct device *dev, int virq,
 					     int nvec,
 					     struct platform_msi_priv_data *data)

 {
 	struct msi_desc *desc;
 	int i, base = 0;

 	if (!list_empty(dev_to_msi_list(dev))) {
 		desc = list_last_entry(dev_to_msi_list(dev),
 				       struct msi_desc, list);
 		base = desc->platform.msi_index + 1;
 	}

 	for (i = 0; i < nvec; i++) {
 		desc = alloc_msi_entry(dev);
 		if (!desc)
 			break;

 		desc->platform.msi_priv_data = data;
 		desc->platform.msi_index = base + i;
 		desc->nvec_used = 1;
 		desc->irq = virq ? virq + i : 0;

 		list_add_tail(&desc->list, dev_to_msi_list(dev));
 	}

 	if (i != nvec) {
 		/* Clean up the mess */
 		platform_msi_free_descs(dev, base, nvec);

 		return -ENOMEM;
 	}

 	return 0;
 }

 static int platform_msi_alloc_descs(struct device *dev, int nvec,
 				    struct platform_msi_priv_data *data)

 {
 	return platform_msi_alloc_descs_with_irq(dev, 0, nvec, data);
 }

 /**
  * platform_msi_create_irq_domain - Create a platform MSI interrupt domain
  * @fwnode:		Optional fwnode of the interrupt controller
  * @info:	MSI domain info
  * @parent:	Parent irq domain
  *
  * Updates the domain and chip ops and creates a platform MSI
  * interrupt domain.
  *
  * Returns:
  * A domain pointer or NULL in case of failure.
  */
 struct irq_domain *platform_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)
 		platform_msi_update_dom_ops(info);
 	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
 		platform_msi_update_chip_ops(info);

 	domain = msi_create_irq_domain(fwnode, info, parent);
 	if (domain)
 		domain->bus_token = DOMAIN_BUS_PLATFORM_MSI;

 	return domain;
 }

 static struct platform_msi_priv_data *
 platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec,
 			     irq_write_msi_msg_t write_msi_msg)
 {
 	struct platform_msi_priv_data *datap;
 	/*
 	 * Limit the number of interrupts to 256 per device. Should we
 	 * need to bump this up, DEV_ID_SHIFT should be adjusted
 	 * accordingly (which would impact the max number of MSI
 	 * capable devices).
 	 */
 	if (!dev->msi_domain || !write_msi_msg || !nvec || nvec > MAX_DEV_MSIS)
 		return ERR_PTR(-EINVAL);

 	if (dev->msi_domain->bus_token != DOMAIN_BUS_PLATFORM_MSI) {
 		dev_err(dev, "Incompatible msi_domain, giving up\n");
 		return ERR_PTR(-EINVAL);
 	}

 	/* Already had a helping of MSI? Greed... */
 	if (!list_empty(dev_to_msi_list(dev)))
 		return ERR_PTR(-EBUSY);

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

 	datap->devid = ida_simple_get(&platform_msi_devid_ida,
 				      0, 1 << DEV_ID_SHIFT, GFP_KERNEL);
 	if (datap->devid < 0) {
 		int err = datap->devid;
 		kfree(datap);
 		return ERR_PTR(err);
 	}

 	datap->write_msg = write_msi_msg;
 	datap->dev = dev;

 	return datap;
 }

 static void platform_msi_free_priv_data(struct platform_msi_priv_data *data)
 {
 	ida_simple_remove(&platform_msi_devid_ida, data->devid);
 	kfree(data);
 }

 /**
  * platform_msi_domain_alloc_irqs - Allocate MSI interrupts for @dev
  * @dev:		The device for which to allocate interrupts
  * @nvec:		The number of interrupts to allocate
  * @write_msi_msg:	Callback to write an interrupt message for @dev
  *
  * Returns:
  * Zero for success, or an error code in case of failure
  */
 int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
 				   irq_write_msi_msg_t write_msi_msg)
 {
 	struct platform_msi_priv_data *priv_data;
 	int err;

 	priv_data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
 	if (IS_ERR(priv_data))
 		return PTR_ERR(priv_data);

 	err = platform_msi_alloc_descs(dev, nvec, priv_data);
 	if (err)
 		goto out_free_priv_data;

 	err = msi_domain_alloc_irqs(dev->msi_domain, dev, nvec);
 	if (err)
 		goto out_free_desc;

 	return 0;

 out_free_desc:
 	platform_msi_free_descs(dev, 0, nvec);
 out_free_priv_data:
 	platform_msi_free_priv_data(priv_data);

 	return err;
 }

 /**
  * platform_msi_domain_free_irqs - Free MSI interrupts for @dev
  * @dev:	The device for which to free interrupts
  */
 void platform_msi_domain_free_irqs(struct device *dev)
 {
 	if (!list_empty(dev_to_msi_list(dev))) {
 		struct msi_desc *desc;

 		desc = first_msi_entry(dev);
 		platform_msi_free_priv_data(desc->platform.msi_priv_data);
 	}

 	msi_domain_free_irqs(dev->msi_domain, dev);
 	platform_msi_free_descs(dev, 0, MAX_DEV_MSIS);
 }

 /**
  * platform_msi_get_host_data - Query the private data associated with
  *                              a platform-msi domain
  * @domain:	The platform-msi domain
  *
  * Returns the private data provided when calling
  * platform_msi_create_device_domain.
  */
 void *platform_msi_get_host_data(struct irq_domain *domain)
 {
 	struct platform_msi_priv_data *data = domain->host_data;
 	return data->host_data;
 }

 /**
  * platform_msi_create_device_domain - Create a platform-msi domain
  *
  * @dev:		The device generating the MSIs
  * @nvec:		The number of MSIs that need to be allocated
  * @write_msi_msg:	Callback to write an interrupt message for @dev
  * @ops:		The hierarchy domain operations to use
  * @host_data:		Private data associated to this domain
  *
  * Returns an irqdomain for @nvec interrupts
  */
 struct irq_domain *
 platform_msi_create_device_domain(struct device *dev,
 				  unsigned int nvec,
 				  irq_write_msi_msg_t write_msi_msg,
 				  const struct irq_domain_ops *ops,
 				  void *host_data)
 {
 	struct platform_msi_priv_data *data;
 	struct irq_domain *domain;
 	int err;

 	data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
 	if (IS_ERR(data))
 		return NULL;

 	data->host_data = host_data;
 	domain = irq_domain_create_hierarchy(dev->msi_domain, 0, nvec,
 					     of_node_to_fwnode(dev->of_node),
 					     ops, data);
 	if (!domain)
 		goto free_priv;

 	err = msi_domain_prepare_irqs(domain->parent, dev, nvec, &data->arg);
 	if (err)
 		goto free_domain;

 	return domain;

 free_domain:
 	irq_domain_remove(domain);
 free_priv:
 	platform_msi_free_priv_data(data);
 	return NULL;
 }

 /**
  * platform_msi_domain_free - Free interrupts associated with a platform-msi
  *                            domain
  *
  * @domain:	The platform-msi domain
  * @virq:	The base irq from which to perform the free operation
  * @nvec:	How many interrupts to free from @virq
  */
 void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq,
 			      unsigned int nvec)
 {
 	struct platform_msi_priv_data *data = domain->host_data;
 	struct msi_desc *desc;
 	for_each_msi_entry(desc, data->dev) {
 		if (WARN_ON(!desc->irq || desc->nvec_used != 1))
 			return;
 		if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
 			continue;

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

 /**
  * platform_msi_domain_alloc - Allocate interrupts associated with
  *			       a platform-msi domain
  *
  * @domain:	The platform-msi domain
  * @virq:	The base irq from which to perform the allocate operation
  * @nvec:	How many interrupts to free from @virq
  *
  * Return 0 on success, or an error code on failure. Must be called
  * with irq_domain_mutex held (which can only be done as part of a
  * top-level interrupt allocation).
  */
 int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
 			      unsigned int nr_irqs)
 {
 	struct platform_msi_priv_data *data = domain->host_data;
 	int err;

 	err = platform_msi_alloc_descs_with_irq(data->dev, virq, nr_irqs, data);
 	if (err)
 		return err;

 	err = msi_domain_populate_irqs(domain->parent, data->dev,
 				       virq, nr_irqs, &data->arg);
 	if (err)
 		platform_msi_domain_free(domain, virq, nr_irqs);

 	return err;
 }
	/*
	* MSI framework for platform devices
	*
	* Copyright (C) 2015 ARM Limited, All Rights Reserved.
	* Author: Marc Zyngier <marc.zyngier@arm.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* 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, see <http://www.gnu.org/licenses/>.
	*/

	#include <linux/device.h>
	#include <linux/idr.h>
	#include <linux/irq.h>
	#include <linux/irqdomain.h>
	#include <linux/msi.h>
	#include <linux/slab.h>

	#define DEV_ID_SHIFT 21
	#define MAX_DEV_MSIS (1 << (32 - DEV_ID_SHIFT))

	/*
	* Internal data structure containing a (made up, but unique) devid
	* and the callback to write the MSI message.
	*/
	struct platform_msi_priv_data {
	struct device *dev;
	void *host_data;
	msi_alloc_info_t arg;
	irq_write_msi_msg_t write_msg;
	int devid;
	};

	/* The devid allocator */
	static DEFINE_IDA(platform_msi_devid_ida);

	#ifdef GENERIC_MSI_DOMAIN_OPS
	/*
	* Convert an msi_desc to a globaly unique identifier (per-device
	* devid + msi_desc position in the msi_list).
	*/
	static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
	{
	u32 devid;

	devid = desc->platform.msi_priv_data->devid;

	return (devid << (32 - DEV_ID_SHIFT)) \| desc->platform.msi_index;
	}

	static void platform_msi_set_desc(msi_alloc_info_t arg, struct msi_desc desc)
	{
	arg->desc = desc;
	arg->hwirq = platform_msi_calc_hwirq(desc);
	}

	static int platform_msi_init(struct irq_domain *domain,
	struct msi_domain_info *info,
	unsigned int virq, irq_hw_number_t hwirq,
	msi_alloc_info_t *arg)
	{
	return irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
	info->chip, info->chip_data);
	}
	#else
	#define platform_msi_set_desc NULL
	#define platform_msi_init NULL
	#endif

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

	BUG_ON(!ops);

	if (ops->msi_init == NULL)
	ops->msi_init = platform_msi_init;
	if (ops->set_desc == NULL)
	ops->set_desc = platform_msi_set_desc;
	}

	static void platform_msi_write_msg(struct irq_data data, struct msi_msg msg)
	{
	struct msi_desc *desc = irq_data_get_msi_desc(data);
	struct platform_msi_priv_data *priv_data;

	priv_data = desc->platform.msi_priv_data;

	priv_data->write_msg(desc, msg);
	}

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

	BUG_ON(!chip);
	if (!chip->irq_mask)
	chip->irq_mask = irq_chip_mask_parent;
	if (!chip->irq_unmask)
	chip->irq_unmask = irq_chip_unmask_parent;
	if (!chip->irq_eoi)
	chip->irq_eoi = irq_chip_eoi_parent;
	if (!chip->irq_set_affinity)
	chip->irq_set_affinity = msi_domain_set_affinity;
	if (!chip->irq_write_msi_msg)
	chip->irq_write_msi_msg = platform_msi_write_msg;
	}

	static void platform_msi_free_descs(struct device *dev, int base, int nvec)
	{
	struct msi_desc desc, tmp;

	list_for_each_entry_safe(desc, tmp, dev_to_msi_list(dev), list) {
	if (desc->platform.msi_index >= base &&
	desc->platform.msi_index < (base + nvec)) {
	list_del(&desc->list);
	free_msi_entry(desc);
	}
	}
	}

	static int platform_msi_alloc_descs_with_irq(struct device *dev, int virq,
	int nvec,
	struct platform_msi_priv_data *data)

	{
	struct msi_desc *desc;
	int i, base = 0;

	if (!list_empty(dev_to_msi_list(dev))) {
	desc = list_last_entry(dev_to_msi_list(dev),
	struct msi_desc, list);
	base = desc->platform.msi_index + 1;
	}

	for (i = 0; i < nvec; i++) {
	desc = alloc_msi_entry(dev);
	if (!desc)
	break;

	desc->platform.msi_priv_data = data;
	desc->platform.msi_index = base + i;
	desc->nvec_used = 1;
	desc->irq = virq ? virq + i : 0;

	list_add_tail(&desc->list, dev_to_msi_list(dev));
	}

	if (i != nvec) {
	/* Clean up the mess */
	platform_msi_free_descs(dev, base, nvec);

	return -ENOMEM;
	}

	return 0;
	}

	static int platform_msi_alloc_descs(struct device *dev, int nvec,
	struct platform_msi_priv_data *data)

	{
	return platform_msi_alloc_descs_with_irq(dev, 0, nvec, data);
	}

	/**
	* platform_msi_create_irq_domain - Create a platform MSI interrupt domain
	* @fwnode: Optional fwnode of the interrupt controller
	* @info: MSI domain info
	* @parent: Parent irq domain
	*
	* Updates the domain and chip ops and creates a platform MSI
	* interrupt domain.
	*
	* Returns:
	* A domain pointer or NULL in case of failure.
	*/
	struct irq_domain platform_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)
	platform_msi_update_dom_ops(info);
	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
	platform_msi_update_chip_ops(info);

	domain = msi_create_irq_domain(fwnode, info, parent);
	if (domain)
	domain->bus_token = DOMAIN_BUS_PLATFORM_MSI;

	return domain;
	}

	static struct platform_msi_priv_data *
	platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec,
	irq_write_msi_msg_t write_msi_msg)
	{
	struct platform_msi_priv_data *datap;
	/*
	* Limit the number of interrupts to 256 per device. Should we
	* need to bump this up, DEV_ID_SHIFT should be adjusted
	* accordingly (which would impact the max number of MSI
	* capable devices).
	*/
	if (!dev->msi_domain \|\| !write_msi_msg \|\| !nvec \|\| nvec > MAX_DEV_MSIS)
	return ERR_PTR(-EINVAL);

	if (dev->msi_domain->bus_token != DOMAIN_BUS_PLATFORM_MSI) {
	dev_err(dev, "Incompatible msi_domain, giving up\n");
	return ERR_PTR(-EINVAL);
	}

	/* Already had a helping of MSI? Greed... */
	if (!list_empty(dev_to_msi_list(dev)))
	return ERR_PTR(-EBUSY);

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

	datap->devid = ida_simple_get(&platform_msi_devid_ida,
	0, 1 << DEV_ID_SHIFT, GFP_KERNEL);
	if (datap->devid < 0) {
	int err = datap->devid;
	kfree(datap);
	return ERR_PTR(err);
	}

	datap->write_msg = write_msi_msg;
	datap->dev = dev;

	return datap;
	}

	static void platform_msi_free_priv_data(struct platform_msi_priv_data *data)
	{
	ida_simple_remove(&platform_msi_devid_ida, data->devid);
	kfree(data);
	}

	/**
	* platform_msi_domain_alloc_irqs - Allocate MSI interrupts for @dev
	* @dev: The device for which to allocate interrupts
	* @nvec: The number of interrupts to allocate
	* @write_msi_msg: Callback to write an interrupt message for @dev
	*
	* Returns:
	* Zero for success, or an error code in case of failure
	*/
	int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
	irq_write_msi_msg_t write_msi_msg)
	{
	struct platform_msi_priv_data *priv_data;
	int err;

	priv_data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
	if (IS_ERR(priv_data))
	return PTR_ERR(priv_data);

	err = platform_msi_alloc_descs(dev, nvec, priv_data);
	if (err)
	goto out_free_priv_data;

	err = msi_domain_alloc_irqs(dev->msi_domain, dev, nvec);
	if (err)
	goto out_free_desc;

	return 0;

	out_free_desc:
	platform_msi_free_descs(dev, 0, nvec);
	out_free_priv_data:
	platform_msi_free_priv_data(priv_data);

	return err;
	}

	/**
	* platform_msi_domain_free_irqs - Free MSI interrupts for @dev
	* @dev: The device for which to free interrupts
	*/
	void platform_msi_domain_free_irqs(struct device *dev)
	{
	if (!list_empty(dev_to_msi_list(dev))) {
	struct msi_desc *desc;

	desc = first_msi_entry(dev);
	platform_msi_free_priv_data(desc->platform.msi_priv_data);
	}

	msi_domain_free_irqs(dev->msi_domain, dev);
	platform_msi_free_descs(dev, 0, MAX_DEV_MSIS);
	}

	/**
	* platform_msi_get_host_data - Query the private data associated with
	* a platform-msi domain
	* @domain: The platform-msi domain
	*
	* Returns the private data provided when calling
	* platform_msi_create_device_domain.
	*/
	void platform_msi_get_host_data(struct irq_domain domain)
	{
	struct platform_msi_priv_data *data = domain->host_data;
	return data->host_data;
	}

	/**
	* platform_msi_create_device_domain - Create a platform-msi domain
	*
	* @dev: The device generating the MSIs
	* @nvec: The number of MSIs that need to be allocated
	* @write_msi_msg: Callback to write an interrupt message for @dev
	* @ops: The hierarchy domain operations to use
	* @host_data: Private data associated to this domain
	*
	* Returns an irqdomain for @nvec interrupts
	*/
	struct irq_domain *
	platform_msi_create_device_domain(struct device *dev,
	unsigned int nvec,
	irq_write_msi_msg_t write_msi_msg,
	const struct irq_domain_ops *ops,
	void *host_data)
	{
	struct platform_msi_priv_data *data;
	struct irq_domain *domain;
	int err;

	data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
	if (IS_ERR(data))
	return NULL;

	data->host_data = host_data;
	domain = irq_domain_create_hierarchy(dev->msi_domain, 0, nvec,
	of_node_to_fwnode(dev->of_node),
	ops, data);
	if (!domain)
	goto free_priv;

	err = msi_domain_prepare_irqs(domain->parent, dev, nvec, &data->arg);
	if (err)
	goto free_domain;

	return domain;

	free_domain:
	irq_domain_remove(domain);
	free_priv:
	platform_msi_free_priv_data(data);
	return NULL;
	}

	/**
	* platform_msi_domain_free - Free interrupts associated with a platform-msi
	* domain
	*
	* @domain: The platform-msi domain
	* @virq: The base irq from which to perform the free operation
	* @nvec: How many interrupts to free from @virq
	*/
	void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq,
	unsigned int nvec)
	{
	struct platform_msi_priv_data *data = domain->host_data;
	struct msi_desc *desc;
	for_each_msi_entry(desc, data->dev) {
	if (WARN_ON(!desc->irq \|\| desc->nvec_used != 1))
	return;
	if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
	continue;

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

	/**
	* platform_msi_domain_alloc - Allocate interrupts associated with
	* a platform-msi domain
	*
	* @domain: The platform-msi domain
	* @virq: The base irq from which to perform the allocate operation
	* @nvec: How many interrupts to free from @virq
	*
	* Return 0 on success, or an error code on failure. Must be called
	* with irq_domain_mutex held (which can only be done as part of a
	* top-level interrupt allocation).
	*/
	int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
	unsigned int nr_irqs)
	{
	struct platform_msi_priv_data *data = domain->host_data;
	int err;

	err = platform_msi_alloc_descs_with_irq(data->dev, virq, nr_irqs, data);
	if (err)
	return err;

	err = msi_domain_populate_irqs(domain->parent, data->dev,
	virq, nr_irqs, &data->arg);
	if (err)
	platform_msi_domain_free(domain, virq, nr_irqs);

	return err;
	}