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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/mm/ioremap.c
downloadlinux-stericsson-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/arm/mm/ioremap.c')
-rw-r--r--arch/arm/mm/ioremap.c172
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);