3 files changed, 99 insertions, 0 deletions

diff --git a/include/linux/io.h b/include/linux/io.h
index 420e2fdf26f6..aa3f5af670b5 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -19,8 +19,12 @@
 #define _LINUX_IO_H
 
 #include <asm/io.h>
+#include <asm/page.h>
 
 void __iowrite32_copy(void __iomem *to, const void *from, size_t count);
 void __iowrite64_copy(void __iomem *to, const void *from, size_t count);
 
+int ioremap_page_range(unsigned long addr, unsigned long end,
+                       unsigned long phys_addr, pgprot_t prot);
+
 #endif /* _LINUX_IO_H */
diff --git a/lib/Makefile b/lib/Makefile
index 402762fead70..ddf3e676e1f4 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -7,6 +7,7 @@ lib-y := errno.o ctype.o string.o vsprintf.o cmdline.o \
          idr.o div64.o int_sqrt.o bitmap.o extable.o prio_tree.o \
          sha1.o
 
+lib-$(CONFIG_MMU) += ioremap.o
 lib-$(CONFIG_SMP) += cpumask.o
 
 lib-y   += kobject.o kref.o kobject_uevent.o klist.o
diff --git a/lib/ioremap.c b/lib/ioremap.c
new file mode 100644
index 000000000000..29c810ec9813
--- /dev/null
+++ b/lib/ioremap.c
@@ -0,0 +1,94 @@
+/*
+ * Re-map IO memory to kernel address space so that we can access it.
+ * This is needed for high PCI addresses that aren't mapped in the
+ * 640k-1MB IO memory area on PC's
+ *
+ * (C) Copyright 1995 1996 Linus Torvalds
+ */
+#include <linux/io.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+
+#include <asm/cacheflush.h>
+#include <asm/pgtable.h>
+
+static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
+                unsigned long end, unsigned long phys_addr, pgprot_t prot)
+{
+        pte_t *pte;
+        unsigned long pfn;
+
+        pfn = phys_addr >> PAGE_SHIFT;
+        pte = pte_alloc_kernel(pmd, addr);
+        if (!pte)
+                return -ENOMEM;
+        do {
+                BUG_ON(!pte_none(*pte));
+                set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
+                pfn++;
+        } while (pte++, addr += PAGE_SIZE, addr != end);
+        return 0;
+}
+
+static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
+                unsigned long end, unsigned long phys_addr, pgprot_t prot)
+{
+        pmd_t *pmd;
+        unsigned long next;
+
+        phys_addr -= addr;
+        pmd = pmd_alloc(&init_mm, pud, addr);
+        if (!pmd)
+                return -ENOMEM;
+        do {
+                next = pmd_addr_end(addr, end);
+                if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, prot))
+                        return -ENOMEM;
+        } while (pmd++, addr = next, addr != end);
+        return 0;
+}
+
+static inline int ioremap_pud_range(pgd_t *pgd, unsigned long addr,
+                unsigned long end, unsigned long phys_addr, pgprot_t prot)
+{
+        pud_t *pud;
+        unsigned long next;
+
+        phys_addr -= addr;
+        pud = pud_alloc(&init_mm, pgd, addr);
+        if (!pud)
+                return -ENOMEM;
+        do {
+                next = pud_addr_end(addr, end);
+                if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, prot))
+                        return -ENOMEM;
+        } while (pud++, addr = next, addr != end);
+        return 0;
+}
+
+int ioremap_page_range(unsigned long addr,
+                       unsigned long end, unsigned long phys_addr, pgprot_t prot)
+{
+        pgd_t *pgd;
+        unsigned long start;
+        unsigned long next;
+        int err;
+
+        BUG_ON(addr >= end);
+
+        flush_cache_all();
+
+        start = addr;
+        phys_addr -= addr;
+        pgd = pgd_offset_k(addr);
+        do {
+                next = pgd_addr_end(addr, end);
+                err = ioremap_pud_range(pgd, addr, next, phys_addr+addr, prot);
+                if (err)
+                        break;
+        } while (pgd++, addr = next, addr != end);
+
+        flush_tlb_all();
+
+        return err;
+}