text: /**
   * PCI Endpoint *Controller* (EPC) library
   *
   * Copyright (C) 2017 Texas Instruments
   * Author: Kishon Vijay Abraham I <kishon@ti.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 of
   * the License 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/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
   * @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, enum pci_epc_irq_type type,
  		      u8 interrupt_num)
  {
  	int ret;
  	unsigned long flags;
  
  	if (IS_ERR(epc))
  		return -EINVAL;
  
  	if (!epc->ops->raise_irq)
  		return 0;
  
  	spin_lock_irqsave(&epc->lock, flags);
  	ret = epc->ops->raise_irq(epc, 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
   *
   * Invoke to get the number of MSI interrupts allocated by the RC
   */
  int pci_epc_get_msi(struct pci_epc *epc)
  {
  	int interrupt;
  	unsigned long flags;
  
  	if (IS_ERR(epc))
  		return 0;
  
  	if (!epc->ops->get_msi)
  		return 0;
  
  	spin_lock_irqsave(&epc->lock, flags);
  	interrupt = epc->ops->get_msi(epc);
  	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
   * @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 interrupts)
  {
  	int ret;
  	u8 encode_int;
  	unsigned long flags;
  
  	if (IS_ERR(epc))
  		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, 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
   * @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, phys_addr_t phys_addr)
  {
  	unsigned long flags;
  
  	if (IS_ERR(epc))
  		return;
  
  	if (!epc->ops->unmap_addr)
  		return;
  
  	spin_lock_irqsave(&epc->lock, flags);
  	epc->ops->unmap_addr(epc, 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
   * @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, phys_addr_t phys_addr,
  		     u64 pci_addr, size_t size)
  {
  	int ret;
  	unsigned long flags;
  
  	if (IS_ERR(epc))
  		return -EINVAL;
  
  	if (!epc->ops->map_addr)
  		return 0;
  
  	spin_lock_irqsave(&epc->lock, flags);
  	ret = epc->ops->map_addr(epc, 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
   * @bar: the BAR number that has to be reset
   *
   * Invoke to reset the BAR of the endpoint device.
   */
  void pci_epc_clear_bar(struct pci_epc *epc, int bar)
  {
  	unsigned long flags;
  
  	if (IS_ERR(epc))
  		return;
  
  	if (!epc->ops->clear_bar)
  		return;
  
  	spin_lock_irqsave(&epc->lock, flags);
  	epc->ops->clear_bar(epc, 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
   * @bar: the BAR number that has to be configured
   * @size: the size of the addr space
   * @flags: specify memory allocation/io allocation/32bit address/64 bit address
   *
   * Invoke to configure the BAR of the endpoint device.
   */
  int pci_epc_set_bar(struct pci_epc *epc, enum pci_barno bar,
  		    dma_addr_t bar_phys, size_t size, int flags)
  {
  	int ret;
  	unsigned long irq_flags;
  
  	if (IS_ERR(epc))
  		return -EINVAL;
  
  	if (!epc->ops->set_bar)
  		return 0;
  
  	spin_lock_irqsave(&epc->lock, irq_flags);
  	ret = epc->ops->set_bar(epc, bar, bar_phys, size, flags);
  	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
   * @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, struct pci_epf_header *header)
  {
  	int ret;
  	unsigned long flags;
  
  	if (IS_ERR(epc))
  		return -EINVAL;
  
  	if (!epc->ops->write_header)
  		return 0;
  
  	spin_lock_irqsave(&epc->lock, flags);
  	ret = epc->ops->write_header(epc, 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");
  