// SPDX-License-Identifier: GPL-2.0

  /*
   * Implement the default iomap interfaces
   *
   * (C) Copyright 2004 Linus Torvalds
   */
  #include <linux/pci.h>
  #include <linux/io.h>
  
  #include <linux/export.h>
  
  #ifdef CONFIG_PCI
  /**

   * pci_iomap_range - create a virtual mapping cookie for a PCI BAR

   * @dev: PCI device that owns the BAR
   * @bar: BAR number

   * @offset: map memory at the given offset in BAR
   * @maxlen: max length of the memory to map

   *
   * Using this function you will get a __iomem address to your device BAR.
   * You can access it using ioread*() and iowrite*(). These functions hide
   * the details if this is a MMIO or PIO address space and will just do what
   * you expect from them in the correct way.
   *
   * @maxlen specifies the maximum length to map. If you want to get access to

   * the complete BAR from offset to the end, pass %0 here.

   * */

  void __iomem *pci_iomap_range(struct pci_dev *dev,
  			      int bar,
  			      unsigned long offset,
  			      unsigned long maxlen)

  {
  	resource_size_t start = pci_resource_start(dev, bar);
  	resource_size_t len = pci_resource_len(dev, bar);
  	unsigned long flags = pci_resource_flags(dev, bar);

  	if (len <= offset || !start)

  		return NULL;

  	len -= offset;
  	start += offset;

  	if (maxlen && len > maxlen)
  		len = maxlen;
  	if (flags & IORESOURCE_IO)

  		return __pci_ioport_map(dev, start, len);

  	if (flags & IORESOURCE_MEM)
  		return ioremap(start, len);

  	/* What? */
  	return NULL;
  }

  EXPORT_SYMBOL(pci_iomap_range);

  /**

   * pci_iomap_wc_range - create a virtual WC mapping cookie for a PCI BAR
   * @dev: PCI device that owns the BAR
   * @bar: BAR number
   * @offset: map memory at the given offset in BAR
   * @maxlen: max length of the memory to map
   *
   * Using this function you will get a __iomem address to your device BAR.
   * You can access it using ioread*() and iowrite*(). These functions hide
   * the details if this is a MMIO or PIO address space and will just do what
   * you expect from them in the correct way. When possible write combining
   * is used.
   *
   * @maxlen specifies the maximum length to map. If you want to get access to
   * the complete BAR from offset to the end, pass %0 here.
   * */
  void __iomem *pci_iomap_wc_range(struct pci_dev *dev,
  				 int bar,
  				 unsigned long offset,
  				 unsigned long maxlen)
  {
  	resource_size_t start = pci_resource_start(dev, bar);
  	resource_size_t len = pci_resource_len(dev, bar);
  	unsigned long flags = pci_resource_flags(dev, bar);
  
  
  	if (flags & IORESOURCE_IO)
  		return NULL;
  
  	if (len <= offset || !start)
  		return NULL;
  
  	len -= offset;
  	start += offset;
  	if (maxlen && len > maxlen)
  		len = maxlen;
  
  	if (flags & IORESOURCE_MEM)
  		return ioremap_wc(start, len);
  
  	/* What? */
  	return NULL;
  }
  EXPORT_SYMBOL_GPL(pci_iomap_wc_range);
  
  /**

   * pci_iomap - create a virtual mapping cookie for a PCI BAR
   * @dev: PCI device that owns the BAR
   * @bar: BAR number
   * @maxlen: length of the memory to map
   *
   * Using this function you will get a __iomem address to your device BAR.
   * You can access it using ioread*() and iowrite*(). These functions hide
   * the details if this is a MMIO or PIO address space and will just do what
   * you expect from them in the correct way.
   *
   * @maxlen specifies the maximum length to map. If you want to get access to
   * the complete BAR without checking for its length first, pass %0 here.
   * */
  void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
  {
  	return pci_iomap_range(dev, bar, 0, maxlen);
  }

  EXPORT_SYMBOL(pci_iomap);

  
  /**
   * pci_iomap_wc - create a virtual WC mapping cookie for a PCI BAR
   * @dev: PCI device that owns the BAR
   * @bar: BAR number
   * @maxlen: length of the memory to map
   *
   * Using this function you will get a __iomem address to your device BAR.
   * You can access it using ioread*() and iowrite*(). These functions hide
   * the details if this is a MMIO or PIO address space and will just do what
   * you expect from them in the correct way. When possible write combining
   * is used.
   *
   * @maxlen specifies the maximum length to map. If you want to get access to
   * the complete BAR without checking for its length first, pass %0 here.
   * */
  void __iomem *pci_iomap_wc(struct pci_dev *dev, int bar, unsigned long maxlen)
  {
  	return pci_iomap_wc_range(dev, bar, 0, maxlen);
  }
  EXPORT_SYMBOL_GPL(pci_iomap_wc);

  #endif /* CONFIG_PCI */