drivers/pci/endpoint/pci-epc-core.c - third_party/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /**
  * PCI Endpoint *Controller* (EPC) library
  *
  * Copyright (C) 2017 Texas Instruments
  * Author: Kishon Vijay Abraham I <kishon@ti.com>
  */

 #include <linux/device.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/of_device.h>

 #include <linux/pci-epc.h>
 #include <linux/pci-epf.h>
 #include <linux/pci-ep-cfs.h>

 static struct class *pci_epc_class;

 static void devm_pci_epc_release(struct device *dev, void *res)
 {
 	struct pci_epc *epc = *(struct pci_epc **)res;

 	pci_epc_destroy(epc);
 }

 static int devm_pci_epc_match(struct device *dev, void *res, void *match_data)
 {
 	struct pci_epc **epc = res;

 	return *epc == match_data;
 }

 /**
  * pci_epc_put() - release the PCI endpoint controller
  * @epc: epc returned by pci_epc_get()
  *
  * release the refcount the caller obtained by invoking pci_epc_get()
  */
 void pci_epc_put(struct pci_epc *epc)
 {
 	if (!epc || IS_ERR(epc))
 		return;

 	module_put(epc->ops->owner);
 	put_device(&epc->dev);
 }
 EXPORT_SYMBOL_GPL(pci_epc_put);

 /**
  * pci_epc_get() - get the PCI endpoint controller
  * @epc_name: device name of the endpoint controller
  *
  * Invoke to get struct pci_epc * corresponding to the device name of the
  * endpoint controller
  */
 struct pci_epc *pci_epc_get(const char *epc_name)
 {
 	int ret = -EINVAL;
 	struct pci_epc *epc;
 	struct device *dev;
 	struct class_dev_iter iter;

 	class_dev_iter_init(&iter, pci_epc_class, NULL, NULL);
 	while ((dev = class_dev_iter_next(&iter))) {
 		if (strcmp(epc_name, dev_name(dev)))
 			continue;

 		epc = to_pci_epc(dev);
 		if (!try_module_get(epc->ops->owner)) {
 			ret = -EINVAL;
 			goto err;
 		}

 		class_dev_iter_exit(&iter);
 		get_device(&epc->dev);
 		return epc;
 	}

 err:
 	class_dev_iter_exit(&iter);
 	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(pci_epc_get);

 /**
  * pci_epc_stop() - stop the PCI link
  * @epc: the link of the EPC device that has to be stopped
  *
  * Invoke to stop the PCI link
  */
 void pci_epc_stop(struct pci_epc *epc)
 {
 	unsigned long flags;

 	if (IS_ERR(epc) || !epc->ops->stop)
 		return;

 	spin_lock_irqsave(&epc->lock, flags);
 	epc->ops->stop(epc);
 	spin_unlock_irqrestore(&epc->lock, flags);
 }
 EXPORT_SYMBOL_GPL(pci_epc_stop);

 /**
  * pci_epc_start() - start the PCI link
  * @epc: the link of *this* EPC device has to be started
  *
  * Invoke to start the PCI link
  */
 int pci_epc_start(struct pci_epc *epc)
 {
 	int ret;
 	unsigned long flags;

 	if (IS_ERR(epc))
 		return -EINVAL;

 	if (!epc->ops->start)
 		return 0;

 	spin_lock_irqsave(&epc->lock, flags);
 	ret = epc->ops->start(epc);
 	spin_unlock_irqrestore(&epc->lock, flags);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(pci_epc_start);

 /**
  * pci_epc_raise_irq() - interrupt the host system
  * @epc: the EPC device which has to interrupt the host
  * @func_no: the endpoint function number in the EPC device
  * @type: specify the type of interrupt; legacy or MSI
  * @interrupt_num: the MSI interrupt number
  *
  * Invoke to raise an MSI or legacy interrupt
  */
 int pci_epc_raise_irq(struct pci_epc *epc, u8 func_no,
 		      enum pci_epc_irq_type type, u8 interrupt_num)
 {
 	int ret;
 	unsigned long flags;

 	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
 		return -EINVAL;

 	if (!epc->ops->raise_irq)
 		return 0;

 	spin_lock_irqsave(&epc->lock, flags);
 	ret = epc->ops->raise_irq(epc, func_no, type, interrupt_num);
 	spin_unlock_irqrestore(&epc->lock, flags);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(pci_epc_raise_irq);

 /**
  * pci_epc_get_msi() - get the number of MSI interrupt numbers allocated
  * @epc: the EPC device to which MSI interrupts was requested
  * @func_no: the endpoint function number in the EPC device
  *
  * Invoke to get the number of MSI interrupts allocated by the RC
  */
 int pci_epc_get_msi(struct pci_epc *epc, u8 func_no)
 {
 	int interrupt;
 	unsigned long flags;

 	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
 		return 0;

 	if (!epc->ops->get_msi)
 		return 0;

 	spin_lock_irqsave(&epc->lock, flags);
 	interrupt = epc->ops->get_msi(epc, func_no);
 	spin_unlock_irqrestore(&epc->lock, flags);

 	if (interrupt < 0)
 		return 0;

 	interrupt = 1 << interrupt;

 	return interrupt;
 }
 EXPORT_SYMBOL_GPL(pci_epc_get_msi);

 /**
  * pci_epc_set_msi() - set the number of MSI interrupt numbers required
  * @epc: the EPC device on which MSI has to be configured
  * @func_no: the endpoint function number in the EPC device
  * @interrupts: number of MSI interrupts required by the EPF
  *
  * Invoke to set the required number of MSI interrupts.
  */
 int pci_epc_set_msi(struct pci_epc *epc, u8 func_no, u8 interrupts)
 {
 	int ret;
 	u8 encode_int;
 	unsigned long flags;

 	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
 		return -EINVAL;

 	if (!epc->ops->set_msi)
 		return 0;

 	encode_int = order_base_2(interrupts);

 	spin_lock_irqsave(&epc->lock, flags);
 	ret = epc->ops->set_msi(epc, func_no, encode_int);
 	spin_unlock_irqrestore(&epc->lock, flags);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(pci_epc_set_msi);

 /**
  * pci_epc_unmap_addr() - unmap CPU address from PCI address
  * @epc: the EPC device on which address is allocated
  * @func_no: the endpoint function number in the EPC device
  * @phys_addr: physical address of the local system
  *
  * Invoke to unmap the CPU address from PCI address.
  */
 void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no,
 			phys_addr_t phys_addr)
 {
 	unsigned long flags;

 	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
 		return;

 	if (!epc->ops->unmap_addr)
 		return;

 	spin_lock_irqsave(&epc->lock, flags);
 	epc->ops->unmap_addr(epc, func_no, phys_addr);
 	spin_unlock_irqrestore(&epc->lock, flags);
 }
 EXPORT_SYMBOL_GPL(pci_epc_unmap_addr);

 /**
  * pci_epc_map_addr() - map CPU address to PCI address
  * @epc: the EPC device on which address is allocated
  * @func_no: the endpoint function number in the EPC device
  * @phys_addr: physical address of the local system
  * @pci_addr: PCI address to which the physical address should be mapped
  * @size: the size of the allocation
  *
  * Invoke to map CPU address with PCI address.
  */
 int pci_epc_map_addr(struct pci_epc *epc, u8 func_no,
 		     phys_addr_t phys_addr, u64 pci_addr, size_t size)
 {
 	int ret;
 	unsigned long flags;

 	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
 		return -EINVAL;

 	if (!epc->ops->map_addr)
 		return 0;

 	spin_lock_irqsave(&epc->lock, flags);
 	ret = epc->ops->map_addr(epc, func_no, phys_addr, pci_addr, size);
 	spin_unlock_irqrestore(&epc->lock, flags);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(pci_epc_map_addr);

 /**
  * pci_epc_clear_bar() - reset the BAR
  * @epc: the EPC device for which the BAR has to be cleared
  * @func_no: the endpoint function number in the EPC device
  * @epf_bar: the struct epf_bar that contains the BAR information
  *
  * Invoke to reset the BAR of the endpoint device.
  */
 void pci_epc_clear_bar(struct pci_epc *epc, u8 func_no,
 		       struct pci_epf_bar *epf_bar)
 {
 	unsigned long flags;

 	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions ||
 	    (epf_bar->barno == BAR_5 &&
 	     epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64))
 		return;

 	if (!epc->ops->clear_bar)
 		return;

 	spin_lock_irqsave(&epc->lock, flags);
 	epc->ops->clear_bar(epc, func_no, epf_bar);
 	spin_unlock_irqrestore(&epc->lock, flags);
 }
 EXPORT_SYMBOL_GPL(pci_epc_clear_bar);

 /**
  * pci_epc_set_bar() - configure BAR in order for host to assign PCI addr space
  * @epc: the EPC device on which BAR has to be configured
  * @func_no: the endpoint function number in the EPC device
  * @epf_bar: the struct epf_bar that contains the BAR information
  *
  * Invoke to configure the BAR of the endpoint device.
  */
 int pci_epc_set_bar(struct pci_epc *epc, u8 func_no,
 		    struct pci_epf_bar *epf_bar)
 {
 	int ret;
 	unsigned long irq_flags;
 	int flags = epf_bar->flags;

 	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions ||
 	    (epf_bar->barno == BAR_5 &&
 	     flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ||
 	    (flags & PCI_BASE_ADDRESS_SPACE_IO &&
 	     flags & PCI_BASE_ADDRESS_IO_MASK) ||
 	    (upper_32_bits(epf_bar->size) &&
 	     !(flags & PCI_BASE_ADDRESS_MEM_TYPE_64)))
 		return -EINVAL;

 	if (!epc->ops->set_bar)
 		return 0;

 	spin_lock_irqsave(&epc->lock, irq_flags);
 	ret = epc->ops->set_bar(epc, func_no, epf_bar);
 	spin_unlock_irqrestore(&epc->lock, irq_flags);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(pci_epc_set_bar);

 /**
  * pci_epc_write_header() - write standard configuration header
  * @epc: the EPC device to which the configuration header should be written
  * @func_no: the endpoint function number in the EPC device
  * @header: standard configuration header fields
  *
  * Invoke to write the configuration header to the endpoint controller. Every
  * endpoint controller will have a dedicated location to which the standard
  * configuration header would be written. The callback function should write
  * the header fields to this dedicated location.
  */
 int pci_epc_write_header(struct pci_epc *epc, u8 func_no,
 			 struct pci_epf_header *header)
 {
 	int ret;
 	unsigned long flags;

 	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
 		return -EINVAL;

 	if (!epc->ops->write_header)
 		return 0;

 	spin_lock_irqsave(&epc->lock, flags);
 	ret = epc->ops->write_header(epc, func_no, header);
 	spin_unlock_irqrestore(&epc->lock, flags);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(pci_epc_write_header);

 /**
  * pci_epc_add_epf() - bind PCI endpoint function to an endpoint controller
  * @epc: the EPC device to which the endpoint function should be added
  * @epf: the endpoint function to be added
  *
  * A PCI endpoint device can have one or more functions. In the case of PCIe,
  * the specification allows up to 8 PCIe endpoint functions. Invoke
  * pci_epc_add_epf() to add a PCI endpoint function to an endpoint controller.
  */
 int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf)
 {
 	unsigned long flags;

 	if (epf->epc)
 		return -EBUSY;

 	if (IS_ERR(epc))
 		return -EINVAL;

 	if (epf->func_no > epc->max_functions - 1)
 		return -EINVAL;

 	epf->epc = epc;

 	spin_lock_irqsave(&epc->lock, flags);
 	list_add_tail(&epf->list, &epc->pci_epf);
 	spin_unlock_irqrestore(&epc->lock, flags);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(pci_epc_add_epf);

 /**
  * pci_epc_remove_epf() - remove PCI endpoint function from endpoint controller
  * @epc: the EPC device from which the endpoint function should be removed
  * @epf: the endpoint function to be removed
  *
  * Invoke to remove PCI endpoint function from the endpoint controller.
  */
 void pci_epc_remove_epf(struct pci_epc *epc, struct pci_epf *epf)
 {
 	unsigned long flags;

 	if (!epc || IS_ERR(epc))
 		return;

 	spin_lock_irqsave(&epc->lock, flags);
 	list_del(&epf->list);
 	spin_unlock_irqrestore(&epc->lock, flags);
 }
 EXPORT_SYMBOL_GPL(pci_epc_remove_epf);

 /**
  * pci_epc_linkup() - Notify the EPF device that EPC device has established a
  *		      connection with the Root Complex.
  * @epc: the EPC device which has established link with the host
  *
  * Invoke to Notify the EPF device that the EPC device has established a
  * connection with the Root Complex.
  */
 void pci_epc_linkup(struct pci_epc *epc)
 {
 	unsigned long flags;
 	struct pci_epf *epf;

 	if (!epc || IS_ERR(epc))
 		return;

 	spin_lock_irqsave(&epc->lock, flags);
 	list_for_each_entry(epf, &epc->pci_epf, list)
 		pci_epf_linkup(epf);
 	spin_unlock_irqrestore(&epc->lock, flags);
 }
 EXPORT_SYMBOL_GPL(pci_epc_linkup);

 /**
  * pci_epc_destroy() - destroy the EPC device
  * @epc: the EPC device that has to be destroyed
  *
  * Invoke to destroy the PCI EPC device
  */
 void pci_epc_destroy(struct pci_epc *epc)
 {
 	pci_ep_cfs_remove_epc_group(epc->group);
 	device_unregister(&epc->dev);
 	kfree(epc);
 }
 EXPORT_SYMBOL_GPL(pci_epc_destroy);

 /**
  * devm_pci_epc_destroy() - destroy the EPC device
  * @dev: device that wants to destroy the EPC
  * @epc: the EPC device that has to be destroyed
  *
  * Invoke to destroy the devres associated with this
  * pci_epc and destroy the EPC device.
  */
 void devm_pci_epc_destroy(struct device *dev, struct pci_epc *epc)
 {
 	int r;

 	r = devres_destroy(dev, devm_pci_epc_release, devm_pci_epc_match,
 			   epc);
 	dev_WARN_ONCE(dev, r, "couldn't find PCI EPC resource\n");
 }
 EXPORT_SYMBOL_GPL(devm_pci_epc_destroy);

 /**
  * __pci_epc_create() - create a new endpoint controller (EPC) device
  * @dev: device that is creating the new EPC
  * @ops: function pointers for performing EPC operations
  * @owner: the owner of the module that creates the EPC device
  *
  * Invoke to create a new EPC device and add it to pci_epc class.
  */
 struct pci_epc *
 __pci_epc_create(struct device *dev, const struct pci_epc_ops *ops,
 		 struct module *owner)
 {
 	int ret;
 	struct pci_epc *epc;

 	if (WARN_ON(!dev)) {
 		ret = -EINVAL;
 		goto err_ret;
 	}

 	epc = kzalloc(sizeof(*epc), GFP_KERNEL);
 	if (!epc) {
 		ret = -ENOMEM;
 		goto err_ret;
 	}

 	spin_lock_init(&epc->lock);
 	INIT_LIST_HEAD(&epc->pci_epf);

 	device_initialize(&epc->dev);
 	epc->dev.class = pci_epc_class;
 	epc->dev.parent = dev;
 	epc->ops = ops;

 	ret = dev_set_name(&epc->dev, "%s", dev_name(dev));
 	if (ret)
 		goto put_dev;

 	ret = device_add(&epc->dev);
 	if (ret)
 		goto put_dev;

 	epc->group = pci_ep_cfs_add_epc_group(dev_name(dev));

 	return epc;

 put_dev:
 	put_device(&epc->dev);
 	kfree(epc);

 err_ret:
 	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(__pci_epc_create);

 /**
  * __devm_pci_epc_create() - create a new endpoint controller (EPC) device
  * @dev: device that is creating the new EPC
  * @ops: function pointers for performing EPC operations
  * @owner: the owner of the module that creates the EPC device
  *
  * Invoke to create a new EPC device and add it to pci_epc class.
  * While at that, it also associates the device with the pci_epc using devres.
  * On driver detach, release function is invoked on the devres data,
  * then, devres data is freed.
  */
 struct pci_epc *
 __devm_pci_epc_create(struct device *dev, const struct pci_epc_ops *ops,
 		      struct module *owner)
 {
 	struct pci_epc **ptr, *epc;

 	ptr = devres_alloc(devm_pci_epc_release, sizeof(*ptr), GFP_KERNEL);
 	if (!ptr)
 		return ERR_PTR(-ENOMEM);

 	epc = __pci_epc_create(dev, ops, owner);
 	if (!IS_ERR(epc)) {
 		*ptr = epc;
 		devres_add(dev, ptr);
 	} else {
 		devres_free(ptr);
 	}

 	return epc;
 }
 EXPORT_SYMBOL_GPL(__devm_pci_epc_create);

 static int __init pci_epc_init(void)
 {
 	pci_epc_class = class_create(THIS_MODULE, "pci_epc");
 	if (IS_ERR(pci_epc_class)) {
 		pr_err("failed to create pci epc class --> %ld\n",
 		       PTR_ERR(pci_epc_class));
 		return PTR_ERR(pci_epc_class);
 	}

 	return 0;
 }
 module_init(pci_epc_init);

 static void __exit pci_epc_exit(void)
 {
 	class_destroy(pci_epc_class);
 }
 module_exit(pci_epc_exit);

 MODULE_DESCRIPTION("PCI EPC Library");
 MODULE_AUTHOR("Kishon Vijay Abraham I <kishon@ti.com>");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/**
	* PCI Endpoint Controller (EPC) library
	*
	* Copyright (C) 2017 Texas Instruments
	* Author: Kishon Vijay Abraham I <kishon@ti.com>
	*/

	#include <linux/device.h>
	#include <linux/slab.h>
	#include <linux/module.h>
	#include <linux/of_device.h>

	#include <linux/pci-epc.h>
	#include <linux/pci-epf.h>
	#include <linux/pci-ep-cfs.h>

	static struct class *pci_epc_class;

	static void devm_pci_epc_release(struct device dev, void res)
	{
	struct pci_epc epc = (struct pci_epc **)res;

	pci_epc_destroy(epc);
	}

	static int devm_pci_epc_match(struct device dev, void res, void *match_data)
	{
	struct pci_epc **epc = res;

	return *epc == match_data;
	}

	/**
	* pci_epc_put() - release the PCI endpoint controller
	* @epc: epc returned by pci_epc_get()
	*
	* release the refcount the caller obtained by invoking pci_epc_get()
	*/
	void pci_epc_put(struct pci_epc *epc)
	{
	if (!epc \|\| IS_ERR(epc))
	return;

	module_put(epc->ops->owner);
	put_device(&epc->dev);
	}
	EXPORT_SYMBOL_GPL(pci_epc_put);

	/**
	* pci_epc_get() - get the PCI endpoint controller
	* @epc_name: device name of the endpoint controller
	*
	* Invoke to get struct pci_epc * corresponding to the device name of the
	* endpoint controller
	*/
	struct pci_epc pci_epc_get(const char epc_name)
	{
	int ret = -EINVAL;
	struct pci_epc *epc;
	struct device *dev;
	struct class_dev_iter iter;

	class_dev_iter_init(&iter, pci_epc_class, NULL, NULL);
	while ((dev = class_dev_iter_next(&iter))) {
	if (strcmp(epc_name, dev_name(dev)))
	continue;

	epc = to_pci_epc(dev);
	if (!try_module_get(epc->ops->owner)) {
	ret = -EINVAL;
	goto err;
	}

	class_dev_iter_exit(&iter);
	get_device(&epc->dev);
	return epc;
	}

	err:
	class_dev_iter_exit(&iter);
	return ERR_PTR(ret);
	}
	EXPORT_SYMBOL_GPL(pci_epc_get);

	/**
	* pci_epc_stop() - stop the PCI link
	* @epc: the link of the EPC device that has to be stopped
	*
	* Invoke to stop the PCI link
	*/
	void pci_epc_stop(struct pci_epc *epc)
	{
	unsigned long flags;

	if (IS_ERR(epc) \|\| !epc->ops->stop)
	return;

	spin_lock_irqsave(&epc->lock, flags);
	epc->ops->stop(epc);
	spin_unlock_irqrestore(&epc->lock, flags);
	}
	EXPORT_SYMBOL_GPL(pci_epc_stop);

	/**
	* pci_epc_start() - start the PCI link
	* @epc: the link of this EPC device has to be started
	*
	* Invoke to start the PCI link
	*/
	int pci_epc_start(struct pci_epc *epc)
	{
	int ret;
	unsigned long flags;

	if (IS_ERR(epc))
	return -EINVAL;

	if (!epc->ops->start)
	return 0;

	spin_lock_irqsave(&epc->lock, flags);
	ret = epc->ops->start(epc);
	spin_unlock_irqrestore(&epc->lock, flags);

	return ret;
	}
	EXPORT_SYMBOL_GPL(pci_epc_start);

	/**
	* pci_epc_raise_irq() - interrupt the host system
	* @epc: the EPC device which has to interrupt the host
	* @func_no: the endpoint function number in the EPC device
	* @type: specify the type of interrupt; legacy or MSI
	* @interrupt_num: the MSI interrupt number
	*
	* Invoke to raise an MSI or legacy interrupt
	*/
	int pci_epc_raise_irq(struct pci_epc *epc, u8 func_no,
	enum pci_epc_irq_type type, u8 interrupt_num)
	{
	int ret;
	unsigned long flags;

	if (IS_ERR_OR_NULL(epc) \|\| func_no >= epc->max_functions)
	return -EINVAL;

	if (!epc->ops->raise_irq)
	return 0;

	spin_lock_irqsave(&epc->lock, flags);
	ret = epc->ops->raise_irq(epc, func_no, type, interrupt_num);
	spin_unlock_irqrestore(&epc->lock, flags);

	return ret;
	}
	EXPORT_SYMBOL_GPL(pci_epc_raise_irq);

	/**
	* pci_epc_get_msi() - get the number of MSI interrupt numbers allocated
	* @epc: the EPC device to which MSI interrupts was requested
	* @func_no: the endpoint function number in the EPC device
	*
	* Invoke to get the number of MSI interrupts allocated by the RC
	*/
	int pci_epc_get_msi(struct pci_epc *epc, u8 func_no)
	{
	int interrupt;
	unsigned long flags;

	if (IS_ERR_OR_NULL(epc) \|\| func_no >= epc->max_functions)
	return 0;

	if (!epc->ops->get_msi)
	return 0;

	spin_lock_irqsave(&epc->lock, flags);
	interrupt = epc->ops->get_msi(epc, func_no);
	spin_unlock_irqrestore(&epc->lock, flags);

	if (interrupt < 0)
	return 0;

	interrupt = 1 << interrupt;

	return interrupt;
	}
	EXPORT_SYMBOL_GPL(pci_epc_get_msi);

	/**
	* pci_epc_set_msi() - set the number of MSI interrupt numbers required
	* @epc: the EPC device on which MSI has to be configured
	* @func_no: the endpoint function number in the EPC device
	* @interrupts: number of MSI interrupts required by the EPF
	*
	* Invoke to set the required number of MSI interrupts.
	*/
	int pci_epc_set_msi(struct pci_epc *epc, u8 func_no, u8 interrupts)
	{
	int ret;
	u8 encode_int;
	unsigned long flags;

	if (IS_ERR_OR_NULL(epc) \|\| func_no >= epc->max_functions)
	return -EINVAL;

	if (!epc->ops->set_msi)
	return 0;

	encode_int = order_base_2(interrupts);

	spin_lock_irqsave(&epc->lock, flags);
	ret = epc->ops->set_msi(epc, func_no, encode_int);
	spin_unlock_irqrestore(&epc->lock, flags);

	return ret;
	}
	EXPORT_SYMBOL_GPL(pci_epc_set_msi);

	/**
	* pci_epc_unmap_addr() - unmap CPU address from PCI address
	* @epc: the EPC device on which address is allocated
	* @func_no: the endpoint function number in the EPC device
	* @phys_addr: physical address of the local system
	*
	* Invoke to unmap the CPU address from PCI address.
	*/
	void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no,
	phys_addr_t phys_addr)
	{
	unsigned long flags;

	if (IS_ERR_OR_NULL(epc) \|\| func_no >= epc->max_functions)
	return;

	if (!epc->ops->unmap_addr)
	return;

	spin_lock_irqsave(&epc->lock, flags);
	epc->ops->unmap_addr(epc, func_no, phys_addr);
	spin_unlock_irqrestore(&epc->lock, flags);
	}
	EXPORT_SYMBOL_GPL(pci_epc_unmap_addr);

	/**
	* pci_epc_map_addr() - map CPU address to PCI address
	* @epc: the EPC device on which address is allocated
	* @func_no: the endpoint function number in the EPC device
	* @phys_addr: physical address of the local system
	* @pci_addr: PCI address to which the physical address should be mapped
	* @size: the size of the allocation
	*
	* Invoke to map CPU address with PCI address.
	*/
	int pci_epc_map_addr(struct pci_epc *epc, u8 func_no,
	phys_addr_t phys_addr, u64 pci_addr, size_t size)
	{
	int ret;
	unsigned long flags;

	if (IS_ERR_OR_NULL(epc) \|\| func_no >= epc->max_functions)
	return -EINVAL;

	if (!epc->ops->map_addr)
	return 0;

	spin_lock_irqsave(&epc->lock, flags);
	ret = epc->ops->map_addr(epc, func_no, phys_addr, pci_addr, size);
	spin_unlock_irqrestore(&epc->lock, flags);

	return ret;
	}
	EXPORT_SYMBOL_GPL(pci_epc_map_addr);

	/**
	* pci_epc_clear_bar() - reset the BAR
	* @epc: the EPC device for which the BAR has to be cleared
	* @func_no: the endpoint function number in the EPC device
	* @epf_bar: the struct epf_bar that contains the BAR information
	*
	* Invoke to reset the BAR of the endpoint device.
	*/
	void pci_epc_clear_bar(struct pci_epc *epc, u8 func_no,
	struct pci_epf_bar *epf_bar)
	{
	unsigned long flags;

	if (IS_ERR_OR_NULL(epc) \|\| func_no >= epc->max_functions \|\|
	(epf_bar->barno == BAR_5 &&
	epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64))
	return;

	if (!epc->ops->clear_bar)
	return;

	spin_lock_irqsave(&epc->lock, flags);
	epc->ops->clear_bar(epc, func_no, epf_bar);
	spin_unlock_irqrestore(&epc->lock, flags);
	}
	EXPORT_SYMBOL_GPL(pci_epc_clear_bar);

	/**
	* pci_epc_set_bar() - configure BAR in order for host to assign PCI addr space
	* @epc: the EPC device on which BAR has to be configured
	* @func_no: the endpoint function number in the EPC device
	* @epf_bar: the struct epf_bar that contains the BAR information
	*
	* Invoke to configure the BAR of the endpoint device.
	*/
	int pci_epc_set_bar(struct pci_epc *epc, u8 func_no,
	struct pci_epf_bar *epf_bar)
	{
	int ret;
	unsigned long irq_flags;
	int flags = epf_bar->flags;

	if (IS_ERR_OR_NULL(epc) \|\| func_no >= epc->max_functions \|\|
	(epf_bar->barno == BAR_5 &&
	flags & PCI_BASE_ADDRESS_MEM_TYPE_64) \|\|
	(flags & PCI_BASE_ADDRESS_SPACE_IO &&
	flags & PCI_BASE_ADDRESS_IO_MASK) \|\|
	(upper_32_bits(epf_bar->size) &&
	!(flags & PCI_BASE_ADDRESS_MEM_TYPE_64)))
	return -EINVAL;

	if (!epc->ops->set_bar)
	return 0;

	spin_lock_irqsave(&epc->lock, irq_flags);
	ret = epc->ops->set_bar(epc, func_no, epf_bar);
	spin_unlock_irqrestore(&epc->lock, irq_flags);

	return ret;
	}
	EXPORT_SYMBOL_GPL(pci_epc_set_bar);

	/**
	* pci_epc_write_header() - write standard configuration header
	* @epc: the EPC device to which the configuration header should be written
	* @func_no: the endpoint function number in the EPC device
	* @header: standard configuration header fields
	*
	* Invoke to write the configuration header to the endpoint controller. Every
	* endpoint controller will have a dedicated location to which the standard
	* configuration header would be written. The callback function should write
	* the header fields to this dedicated location.
	*/
	int pci_epc_write_header(struct pci_epc *epc, u8 func_no,
	struct pci_epf_header *header)
	{
	int ret;
	unsigned long flags;

	if (IS_ERR_OR_NULL(epc) \|\| func_no >= epc->max_functions)
	return -EINVAL;

	if (!epc->ops->write_header)
	return 0;

	spin_lock_irqsave(&epc->lock, flags);
	ret = epc->ops->write_header(epc, func_no, header);
	spin_unlock_irqrestore(&epc->lock, flags);

	return ret;
	}
	EXPORT_SYMBOL_GPL(pci_epc_write_header);

	/**
	* pci_epc_add_epf() - bind PCI endpoint function to an endpoint controller
	* @epc: the EPC device to which the endpoint function should be added
	* @epf: the endpoint function to be added
	*
	* A PCI endpoint device can have one or more functions. In the case of PCIe,
	* the specification allows up to 8 PCIe endpoint functions. Invoke
	* pci_epc_add_epf() to add a PCI endpoint function to an endpoint controller.
	*/
	int pci_epc_add_epf(struct pci_epc epc, struct pci_epf epf)
	{
	unsigned long flags;

	if (epf->epc)
	return -EBUSY;

	if (IS_ERR(epc))
	return -EINVAL;

	if (epf->func_no > epc->max_functions - 1)
	return -EINVAL;

	epf->epc = epc;

	spin_lock_irqsave(&epc->lock, flags);
	list_add_tail(&epf->list, &epc->pci_epf);
	spin_unlock_irqrestore(&epc->lock, flags);

	return 0;
	}
	EXPORT_SYMBOL_GPL(pci_epc_add_epf);

	/**
	* pci_epc_remove_epf() - remove PCI endpoint function from endpoint controller
	* @epc: the EPC device from which the endpoint function should be removed
	* @epf: the endpoint function to be removed
	*
	* Invoke to remove PCI endpoint function from the endpoint controller.
	*/
	void pci_epc_remove_epf(struct pci_epc epc, struct pci_epf epf)
	{
	unsigned long flags;

	if (!epc \|\| IS_ERR(epc))
	return;

	spin_lock_irqsave(&epc->lock, flags);
	list_del(&epf->list);
	spin_unlock_irqrestore(&epc->lock, flags);
	}
	EXPORT_SYMBOL_GPL(pci_epc_remove_epf);

	/**
	* pci_epc_linkup() - Notify the EPF device that EPC device has established a
	* connection with the Root Complex.
	* @epc: the EPC device which has established link with the host
	*
	* Invoke to Notify the EPF device that the EPC device has established a
	* connection with the Root Complex.
	*/
	void pci_epc_linkup(struct pci_epc *epc)
	{
	unsigned long flags;
	struct pci_epf *epf;

	if (!epc \|\| IS_ERR(epc))
	return;

	spin_lock_irqsave(&epc->lock, flags);
	list_for_each_entry(epf, &epc->pci_epf, list)
	pci_epf_linkup(epf);
	spin_unlock_irqrestore(&epc->lock, flags);
	}
	EXPORT_SYMBOL_GPL(pci_epc_linkup);

	/**
	* pci_epc_destroy() - destroy the EPC device
	* @epc: the EPC device that has to be destroyed
	*
	* Invoke to destroy the PCI EPC device
	*/
	void pci_epc_destroy(struct pci_epc *epc)
	{
	pci_ep_cfs_remove_epc_group(epc->group);
	device_unregister(&epc->dev);
	kfree(epc);
	}
	EXPORT_SYMBOL_GPL(pci_epc_destroy);

	/**
	* devm_pci_epc_destroy() - destroy the EPC device
	* @dev: device that wants to destroy the EPC
	* @epc: the EPC device that has to be destroyed
	*
	* Invoke to destroy the devres associated with this
	* pci_epc and destroy the EPC device.
	*/
	void devm_pci_epc_destroy(struct device dev, struct pci_epc epc)
	{
	int r;

	r = devres_destroy(dev, devm_pci_epc_release, devm_pci_epc_match,
	epc);
	dev_WARN_ONCE(dev, r, "couldn't find PCI EPC resource\n");
	}
	EXPORT_SYMBOL_GPL(devm_pci_epc_destroy);

	/**
	* __pci_epc_create() - create a new endpoint controller (EPC) device
	* @dev: device that is creating the new EPC
	* @ops: function pointers for performing EPC operations
	* @owner: the owner of the module that creates the EPC device
	*
	* Invoke to create a new EPC device and add it to pci_epc class.
	*/
	struct pci_epc *
	__pci_epc_create(struct device dev, const struct pci_epc_ops ops,
	struct module *owner)
	{
	int ret;
	struct pci_epc *epc;

	if (WARN_ON(!dev)) {
	ret = -EINVAL;
	goto err_ret;
	}

	epc = kzalloc(sizeof(*epc), GFP_KERNEL);
	if (!epc) {
	ret = -ENOMEM;
	goto err_ret;
	}

	spin_lock_init(&epc->lock);
	INIT_LIST_HEAD(&epc->pci_epf);

	device_initialize(&epc->dev);
	epc->dev.class = pci_epc_class;
	epc->dev.parent = dev;
	epc->ops = ops;

	ret = dev_set_name(&epc->dev, "%s", dev_name(dev));
	if (ret)
	goto put_dev;

	ret = device_add(&epc->dev);
	if (ret)
	goto put_dev;

	epc->group = pci_ep_cfs_add_epc_group(dev_name(dev));

	return epc;

	put_dev:
	put_device(&epc->dev);
	kfree(epc);

	err_ret:
	return ERR_PTR(ret);
	}
	EXPORT_SYMBOL_GPL(__pci_epc_create);

	/**
	* __devm_pci_epc_create() - create a new endpoint controller (EPC) device
	* @dev: device that is creating the new EPC
	* @ops: function pointers for performing EPC operations
	* @owner: the owner of the module that creates the EPC device
	*
	* Invoke to create a new EPC device and add it to pci_epc class.
	* While at that, it also associates the device with the pci_epc using devres.
	* On driver detach, release function is invoked on the devres data,
	* then, devres data is freed.
	*/
	struct pci_epc *
	__devm_pci_epc_create(struct device dev, const struct pci_epc_ops ops,
	struct module *owner)
	{
	struct pci_epc *ptr, epc;

	ptr = devres_alloc(devm_pci_epc_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
	return ERR_PTR(-ENOMEM);

	epc = __pci_epc_create(dev, ops, owner);
	if (!IS_ERR(epc)) {
	*ptr = epc;
	devres_add(dev, ptr);
	} else {
	devres_free(ptr);
	}

	return epc;
	}
	EXPORT_SYMBOL_GPL(__devm_pci_epc_create);

	static int __init pci_epc_init(void)
	{
	pci_epc_class = class_create(THIS_MODULE, "pci_epc");
	if (IS_ERR(pci_epc_class)) {
	pr_err("failed to create pci epc class --> %ld\n",
	PTR_ERR(pci_epc_class));
	return PTR_ERR(pci_epc_class);
	}

	return 0;
	}
	module_init(pci_epc_init);

	static void __exit pci_epc_exit(void)
	{
	class_destroy(pci_epc_class);
	}
	module_exit(pci_epc_exit);

	MODULE_DESCRIPTION("PCI EPC Library");
	MODULE_AUTHOR("Kishon Vijay Abraham I <kishon@ti.com>");
	MODULE_LICENSE("GPL v2");