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_range - create a virtual mapping cookie for a PCI BAR
  14  * @dev: PCI device that owns the BAR
  15  * @bar: BAR number
  16  * @offset: map memory at the given offset in BAR
  17  * @maxlen: max length of the memory to map
  18  *
  19  * Using this function you will get a __iomem address to your device BAR.
  20  * You can access it using ioread*() and iowrite*(). These functions hide
  21  * the details if this is a MMIO or PIO address space and will just do what
  22  * you expect from them in the correct way.
  23  *
  24  * @maxlen specifies the maximum length to map. If you want to get access to
  25  * the complete BAR from offset to the end, pass %0 here.
  26  * */
  27 void __iomem *pci_iomap_range(struct pci_dev *dev,
  28                               int bar,
  29                               unsigned long offset,
  30                               unsigned long maxlen)
  31 {
  32         resource_size_t start = pci_resource_start(dev, bar);
  33         resource_size_t len = pci_resource_len(dev, bar);
  34         unsigned long flags = pci_resource_flags(dev, bar);
  35
  36         if (len <= offset || !start)
  37                 return NULL;
  38         len -= offset;
  39         start += offset;
  40         if (maxlen && len > maxlen)
  41                 len = maxlen;
  42         if (flags & IORESOURCE_IO)
  43                 return __pci_ioport_map(dev, start, len);
  44         if (flags & IORESOURCE_MEM)
  45                 return ioremap(start, len);
  46         /* What? */
  47         return NULL;
  48 }
  49 EXPORT_SYMBOL(pci_iomap_range);
  50
  51 /**
  52  * pci_iomap - create a virtual mapping cookie for a PCI BAR
  53  * @dev: PCI device that owns the BAR
  54  * @bar: BAR number
  55  * @maxlen: length of the memory to map
  56  *
  57  * Using this function you will get a __iomem address to your device BAR.
  58  * You can access it using ioread*() and iowrite*(). These functions hide
  59  * the details if this is a MMIO or PIO address space and will just do what
  60  * you expect from them in the correct way.
  61  *
  62  * @maxlen specifies the maximum length to map. If you want to get access to
  63  * the complete BAR without checking for its length first, pass %0 here.
  64  * */
  65 void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
  66 {
  67         return pci_iomap_range(dev, bar, 0, maxlen);
  68 }
  69 EXPORT_SYMBOL(pci_iomap);
  70 #endif /* CONFIG_PCI */