linux/lib/pci_iomap.c
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   1/*
   2 * Implement the default iomap interfaces
   3 *
   4 * (C) Copyright 2004 Linus Torvalds
   5 */
   6#include <linux/pci.h>
   7#include <linux/io.h>
   8
   9#include <linux/export.h>
  10
  11#ifdef CONFIG_PCI
  12/**
  13 * pci_iomap - create a virtual mapping cookie for a PCI BAR
  14 * @dev: PCI device that owns the BAR
  15 * @bar: BAR number
  16 * @maxlen: length of the memory to map
  17 *
  18 * Using this function you will get a __iomem address to your device BAR.
  19 * You can access it using ioread*() and iowrite*(). These functions hide
  20 * the details if this is a MMIO or PIO address space and will just do what
  21 * you expect from them in the correct way.
  22 *
  23 * @maxlen specifies the maximum length to map. If you want to get access to
  24 * the complete BAR without checking for its length first, pass %0 here.
  25 * */
  26void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
  27{
  28        resource_size_t start = pci_resource_start(dev, bar);
  29        resource_size_t len = pci_resource_len(dev, bar);
  30        unsigned long flags = pci_resource_flags(dev, bar);
  31
  32        if (!len || !start)
  33                return NULL;
  34        if (maxlen && len > maxlen)
  35                len = maxlen;
  36        if (flags & IORESOURCE_IO)
  37                return __pci_ioport_map(dev, start, len);
  38        if (flags & IORESOURCE_MEM) {
  39                if (flags & IORESOURCE_CACHEABLE)
  40                        return ioremap(start, len);
  41                return ioremap_nocache(start, len);
  42        }
  43        /* What? */
  44        return NULL;
  45}
  46
  47EXPORT_SYMBOL(pci_iomap);
  48#endif /* CONFIG_PCI */
  49
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