1 files changed, 320 insertions, 0 deletions
diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
new file mode 100644
index 00000000..ab506272
--- /dev/null
+++ b/arch/arm/mm/ioremap.c
@@ -0,0 +1,320 @@
+/*
+ *  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 <linux/io.h>
+
+#include <asm/cputype.h>
+#include <asm/cacheflush.h>
+#include <asm/mmu_context.h>
+#include <asm/pgalloc.h>
+#include <asm/tlbflush.h>
+#include <asm/sizes.h>
+
+#include <asm/mach/map.h>
+#include "mm.h"
+
+/*
+ * Used by ioremap() and iounmap() code to mark (super)section-mapped
+ * I/O regions in vm_struct->flags field.
+ */
+#define VM_ARM_SECTION_MAPPING	0x80000000
+
+int ioremap_page(unsigned long virt, unsigned long phys,
+		 const struct mem_type *mtype)
+{
+	return ioremap_page_range(virt, virt + PAGE_SIZE, phys,
+				  __pgprot(mtype->prot_pte));
+}
+EXPORT_SYMBOL(ioremap_page);
+
+void __check_kvm_seq(struct mm_struct *mm)
+{
+	unsigned int seq;
+
+	do {
+		seq = init_mm.context.kvm_seq;
+		memcpy(pgd_offset(mm, VMALLOC_START),
+		       pgd_offset_k(VMALLOC_START),
+		       sizeof(pgd_t) * (pgd_index(VMALLOC_END) -
+					pgd_index(VMALLOC_START)));
+		mm->context.kvm_seq = seq;
+	} while (seq != init_mm.context.kvm_seq);
+}
+
+#ifndef CONFIG_SMP
+/*
+ * Section support is unsafe on SMP - If you iounmap and ioremap a region,
+ * the other CPUs will not see this change until their next context switch.
+ * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
+ * which requires the new ioremap'd region to be referenced, the CPU will
+ * reference the _old_ region.
+ *
+ * Note that get_vm_area_caller() allocates a guard 4K page, so we need to
+ * mask the size back to 1MB aligned or we will overflow in the loop below.
+ */
+static void unmap_area_sections(unsigned long virt, unsigned long size)
+{
+	unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1));
+	pgd_t *pgd;
+
+	flush_cache_vunmap(addr, end);
+	pgd = pgd_offset_k(addr);
+	do {
+		pmd_t pmd, *pmdp = pmd_offset(pgd, addr);
+
+		pmd = *pmdp;
+		if (!pmd_none(pmd)) {
+			/*
+			 * Clear the PMD from the page table, and
+			 * increment the kvm sequence so others
+			 * notice this change.
+			 *
+			 * Note: this is still racy on SMP machines.
+			 */
+			pmd_clear(pmdp);
+			init_mm.context.kvm_seq++;
+
+			/*
+			 * Free the page table, if there was one.
+			 */
+			if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
+				pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
+		}
+
+		addr += PGDIR_SIZE;
+		pgd++;
+	} while (addr < end);
+
+	/*
+	 * Ensure that the active_mm is up to date - we want to
+	 * catch any use-after-iounmap cases.
+	 */
+	if (current->active_mm->context.kvm_seq != init_mm.context.kvm_seq)
+		__check_kvm_seq(current->active_mm);
+
+	flush_tlb_kernel_range(virt, end);
+}
+
+static int
+remap_area_sections(unsigned long virt, unsigned long pfn,
+		    size_t size, const struct mem_type *type)
+{
+	unsigned long addr = virt, end = virt + size;
+	pgd_t *pgd;
+
+	/*
+	 * Remove and free any PTE-based mapping, and
+	 * sync the current kernel mapping.
+	 */
+	unmap_area_sections(virt, size);
+
+	pgd = pgd_offset_k(addr);
+	do {
+		pmd_t *pmd = pmd_offset(pgd, addr);
+
+		pmd[0] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
+		pfn += SZ_1M >> PAGE_SHIFT;
+		pmd[1] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
+		pfn += SZ_1M >> PAGE_SHIFT;
+		flush_pmd_entry(pmd);
+
+		addr += PGDIR_SIZE;
+		pgd++;
+	} while (addr < end);
+
+	return 0;
+}
+
+static int
+remap_area_supersections(unsigned long virt, unsigned long pfn,
+			 size_t size, const struct mem_type *type)
+{
+	unsigned long addr = virt, end = virt + size;
+	pgd_t *pgd;
+
+	/*
+	 * Remove and free any PTE-based mapping, and
+	 * sync the current kernel mapping.
+	 */
+	unmap_area_sections(virt, size);
+
+	pgd = pgd_offset_k(virt);
+	do {
+		unsigned long super_pmd_val, i;
+
+		super_pmd_val = __pfn_to_phys(pfn) | type->prot_sect |
+				PMD_SECT_SUPER;
+		super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20;
+
+		for (i = 0; i < 8; i++) {
+			pmd_t *pmd = pmd_offset(pgd, addr);
+
+			pmd[0] = __pmd(super_pmd_val);
+			pmd[1] = __pmd(super_pmd_val);
+			flush_pmd_entry(pmd);
+
+			addr += PGDIR_SIZE;
+			pgd++;
+		}
+
+		pfn += SUPERSECTION_SIZE >> PAGE_SHIFT;
+	} while (addr < end);
+
+	return 0;
+}
+#endif
+
+void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn,
+	unsigned long offset, size_t size, unsigned int mtype, void *caller)
+{
+	const struct mem_type *type;
+	int err;
+	unsigned long addr;
+ 	struct vm_struct * area;
+
+	/*
+	 * High mappings must be supersection aligned
+	 */
+	if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SUPERSECTION_MASK))
+		return NULL;
+
+	/*
+	 * Don't allow RAM to be mapped - this causes problems with ARMv6+
+	 */
+	if (WARN_ON(pfn_valid(pfn)))
+		return NULL;
+
+	type = get_mem_type(mtype);
+	if (!type)
+		return NULL;
+
+	/*
+	 * Page align the mapping size, taking account of any offset.
+	 */
+	size = PAGE_ALIGN(offset + size);
+
+	area = get_vm_area_caller(size, VM_IOREMAP, caller);
+ 	if (!area)
+ 		return NULL;
+ 	addr = (unsigned long)area->addr;
+
+#ifndef CONFIG_SMP
+	if (DOMAIN_IO == 0 &&
+	    (((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) ||
+	       cpu_is_xsc3()) && pfn >= 0x100000 &&
+	       !((__pfn_to_phys(pfn) | size | addr) & ~SUPERSECTION_MASK)) {
+		area->flags |= VM_ARM_SECTION_MAPPING;
+		err = remap_area_supersections(addr, pfn, size, type);
+	} else if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) {
+		area->flags |= VM_ARM_SECTION_MAPPING;
+		err = remap_area_sections(addr, pfn, size, type);
+	} else
+#endif
+		err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn),
+					 __pgprot(type->prot_pte));
+
+	if (err) {
+ 		vunmap((void *)addr);
+ 		return NULL;
+ 	}
+
+	flush_cache_vmap(addr, addr + size);
+	return (void __iomem *) (offset + addr);
+}
+
+void __iomem *__arm_ioremap_caller(unsigned long phys_addr, size_t size,
+	unsigned int mtype, void *caller)
+{
+	unsigned long last_addr;
+ 	unsigned long offset = phys_addr & ~PAGE_MASK;
+ 	unsigned long pfn = __phys_to_pfn(phys_addr);
+
+ 	/*
+ 	 * Don't allow wraparound or zero size
+	 */
+	last_addr = phys_addr + size - 1;
+	if (!size || last_addr < phys_addr)
+		return NULL;
+
+	return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
+			caller);
+}
+
+/*
+ * 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.
+ */
+void __iomem *
+__arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
+		  unsigned int mtype)
+{
+	return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
+			__builtin_return_address(0));
+}
+EXPORT_SYMBOL(__arm_ioremap_pfn);
+
+void __iomem *
+__arm_ioremap(unsigned long phys_addr, size_t size, unsigned int mtype)
+{
+	return __arm_ioremap_caller(phys_addr, size, mtype,
+			__builtin_return_address(0));
+}
+EXPORT_SYMBOL(__arm_ioremap);
+
+void __iounmap(volatile void __iomem *io_addr)
+{
+	void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
+#ifndef CONFIG_SMP
+	struct vm_struct **p, *tmp;
+
+	/*
+	 * If this is a section based mapping we need to handle it
+	 * specially as the VM subsystem does not know how to handle
+	 * such a beast. We need the lock here b/c we need to clear
+	 * all the mappings before the area can be reclaimed
+	 * by someone else.
+	 */
+	write_lock(&vmlist_lock);
+	for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) {
+		if ((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) {
+			if (tmp->flags & VM_ARM_SECTION_MAPPING) {
+				unmap_area_sections((unsigned long)tmp->addr,
+						    tmp->size);
+			}
+			break;
+		}
+	}
+	write_unlock(&vmlist_lock);
+#endif
+
+	vunmap(addr);
+}
+EXPORT_SYMBOL(__iounmap);