3 files changed, 38 insertions, 0 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index d36f35ff6c5d..6e994fc077f4 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2704,6 +2704,37 @@ int pci_request_regions_exclusive(struct pci_dev *pdev, const char *res_name)
 }
 EXPORT_SYMBOL(pci_request_regions_exclusive);
 
+/**
+ *      pci_remap_iospace - Remap the memory mapped I/O space
+ *      @res: Resource describing the I/O space
+ *      @phys_addr: physical address of range to be mapped
+ *
+ *      Remap the memory mapped I/O space described by the @res
+ *      and the CPU physical address @phys_addr into virtual address space.
+ *      Only architectures that have memory mapped IO functions defined
+ *      (and the PCI_IOBASE value defined) should call this function.
+ */
+int __weak pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
+{
+#if defined(PCI_IOBASE) && defined(CONFIG_MMU)
+        unsigned long vaddr = (unsigned long)PCI_IOBASE + res->start;
+
+        if (!(res->flags & IORESOURCE_IO))
+                return -EINVAL;
+
+        if (res->end > IO_SPACE_LIMIT)
+                return -EINVAL;
+
+        return ioremap_page_range(vaddr, vaddr + resource_size(res), phys_addr,
+                                  pgprot_device(PAGE_KERNEL));
+#else
+        /* this architecture does not have memory mapped I/O space,
+           so this function should never be called */
+        WARN_ONCE(1, "This architecture does not support memory mapped I/O\n");
+        return -ENODEV;
+#endif
+}
+
 static void __pci_set_master(struct pci_dev *dev, bool enable)
 {
         u16 old_cmd, cmd;
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 53b2acc38213..977e545a64c3 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -249,6 +249,10 @@ static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
 #define pgprot_writecombine pgprot_noncached
 #endif
 
+#ifndef pgprot_device
+#define pgprot_device pgprot_noncached
+#endif
+
 /*
  * When walking page tables, get the address of the next boundary,
  * or the end address of the range if that comes earlier.  Although no
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 150da2d644e7..b4995fdfffb1 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1100,6 +1100,9 @@ int __must_check pci_bus_alloc_resource(struct pci_bus *bus,
                                                   resource_size_t),
                         void *alignf_data);
 
+
+int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr);
+
 static inline dma_addr_t pci_bus_address(struct pci_dev *pdev, int bar)
 {
         struct pci_bus_region region;