1 files changed, 172 insertions, 0 deletions

diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
new file mode 100644
index 000000000000..00bb8fd37a59
--- /dev/null
+++ b/arch/arm/mm/ioremap.c
@@ -0,0 +1,172 @@
+/*
+ *  linux/arch/arm/mm/ioremap.c
+ *
+ * Re-map IO memory to kernel address space so that we can access it.
+ *
+ * (C) Copyright 1995 1996 Linus Torvalds
+ *
+ * Hacked for ARM by Phil Blundell <philb@gnu.org>
+ * Hacked to allow all architectures to build, and various cleanups
+ * by Russell King
+ *
+ * This allows a driver to remap an arbitrary region of bus memory into
+ * virtual space.  One should *only* use readl, writel, memcpy_toio and
+ * so on with such remapped areas.
+ *
+ * Because the ARM only has a 32-bit address space we can't address the
+ * whole of the (physical) PCI space at once.  PCI huge-mode addressing
+ * allows us to circumvent this restriction by splitting PCI space into
+ * two 2GB chunks and mapping only one at a time into processor memory.
+ * We use MMU protection domains to trap any attempt to access the bank
+ * that is not currently mapped.  (This isn't fully implemented yet.)
+ */
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+
+#include <asm/cacheflush.h>
+#include <asm/io.h>
+#include <asm/tlbflush.h>
+
+static inline void
+remap_area_pte(pte_t * pte, unsigned long address, unsigned long size,
+               unsigned long phys_addr, pgprot_t pgprot)
+{
+        unsigned long end;
+
+        address &= ~PMD_MASK;
+        end = address + size;
+        if (end > PMD_SIZE)
+                end = PMD_SIZE;
+        BUG_ON(address >= end);
+        do {
+                if (!pte_none(*pte))
+                        goto bad;
+
+                set_pte(pte, pfn_pte(phys_addr >> PAGE_SHIFT, pgprot));
+                address += PAGE_SIZE;
+                phys_addr += PAGE_SIZE;
+                pte++;
+        } while (address && (address < end));
+        return;
+
+ bad:
+        printk("remap_area_pte: page already exists\n");
+        BUG();
+}
+
+static inline int
+remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,
+               unsigned long phys_addr, unsigned long flags)
+{
+        unsigned long end;
+        pgprot_t pgprot;
+
+        address &= ~PGDIR_MASK;
+        end = address + size;
+
+        if (end > PGDIR_SIZE)
+                end = PGDIR_SIZE;
+
+        phys_addr -= address;
+        BUG_ON(address >= end);
+
+        pgprot = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY | L_PTE_WRITE | flags);
+        do {
+                pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
+                if (!pte)
+                        return -ENOMEM;
+                remap_area_pte(pte, address, end - address, address + phys_addr, pgprot);
+                address = (address + PMD_SIZE) & PMD_MASK;
+                pmd++;
+        } while (address && (address < end));
+        return 0;
+}
+
+static int
+remap_area_pages(unsigned long start, unsigned long phys_addr,
+                 unsigned long size, unsigned long flags)
+{
+        unsigned long address = start;
+        unsigned long end = start + size;
+        int err = 0;
+        pgd_t * dir;
+
+        phys_addr -= address;
+        dir = pgd_offset(&init_mm, address);
+        BUG_ON(address >= end);
+        spin_lock(&init_mm.page_table_lock);
+        do {
+                pmd_t *pmd = pmd_alloc(&init_mm, dir, address);
+                if (!pmd) {
+                        err = -ENOMEM;
+                        break;
+                }
+                if (remap_area_pmd(pmd, address, end - address,
+                                         phys_addr + address, flags)) {
+                        err = -ENOMEM;
+                        break;
+                }
+
+                address = (address + PGDIR_SIZE) & PGDIR_MASK;
+                dir++;
+        } while (address && (address < end));
+
+        spin_unlock(&init_mm.page_table_lock);
+        flush_cache_vmap(start, end);
+        return err;
+}
+
+/*
+ * Remap an arbitrary physical address space into the kernel virtual
+ * address space. Needed when the kernel wants to access high addresses
+ * directly.
+ *
+ * NOTE! We need to allow non-page-aligned mappings too: we will obviously
+ * have to convert them into an offset in a page-aligned mapping, but the
+ * caller shouldn't need to know that small detail.
+ *
+ * 'flags' are the extra L_PTE_ flags that you want to specify for this
+ * mapping.  See include/asm-arm/proc-armv/pgtable.h for more information.
+ */
+void __iomem *
+__ioremap(unsigned long phys_addr, size_t size, unsigned long flags,
+          unsigned long align)
+{
+        void * addr;
+        struct vm_struct * area;
+        unsigned long offset, last_addr;
+
+        /* Don't allow wraparound or zero size */
+        last_addr = phys_addr + size - 1;
+        if (!size || last_addr < phys_addr)
+                return NULL;
+
+        /*
+         * Mappings have to be page-aligned
+         */
+        offset = phys_addr & ~PAGE_MASK;
+        phys_addr &= PAGE_MASK;
+        size = PAGE_ALIGN(last_addr + 1) - phys_addr;
+
+        /*
+         * Ok, go for it..
+         */
+        area = get_vm_area(size, VM_IOREMAP);
+        if (!area)
+                return NULL;
+        addr = area->addr;
+        if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
+                vfree(addr);
+                return NULL;
+        }
+        return (void __iomem *) (offset + (char *)addr);
+}
+EXPORT_SYMBOL(__ioremap);
+
+void __iounmap(void __iomem *addr)
+{
+        vfree((void *) (PAGE_MASK & (unsigned long) addr));
+}
+EXPORT_SYMBOL(__iounmap);