Root/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 * */
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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