lib/pci_iomap.c

   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  * */
  26 void __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
  47 EXPORT_SYMBOL(pci_iomap);
  48 #endif /* CONFIG_PCI */