arch/arm/mm/ioremap.c - kernel/msm-4.9 - Gitiles

 /*
  *  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 <linux/sizes.h>

 #include <asm/cp15.h>
 #include <asm/cputype.h>
 #include <asm/cacheflush.h>
 #include <asm/early_ioremap.h>
 #include <asm/mmu_context.h>
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
 #include <asm/system_info.h>

 #include <asm/mach/map.h>
 #include <asm/mach/pci.h>
 #include "mm.h"


 LIST_HEAD(static_vmlist);

 static struct static_vm *find_static_vm_paddr(phys_addr_t paddr,
 			size_t size, unsigned int mtype)
 {
 	struct static_vm *svm;
 	struct vm_struct *vm;

 	list_for_each_entry(svm, &static_vmlist, list) {
 		vm = &svm->vm;
 		if (!(vm->flags & VM_ARM_STATIC_MAPPING))
 			continue;
 		if ((vm->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype))
 			continue;

 		if (vm->phys_addr > paddr ||
 			paddr + size - 1 > vm->phys_addr + vm->size - 1)
 			continue;

 		return svm;
 	}

 	return NULL;
 }

 struct static_vm *find_static_vm_vaddr(void *vaddr)
 {
 	struct static_vm *svm;
 	struct vm_struct *vm;

 	list_for_each_entry(svm, &static_vmlist, list) {
 		vm = &svm->vm;

 		/* static_vmlist is ascending order */
 		if (vm->addr > vaddr)
 			break;

 		if (vm->addr <= vaddr && vm->addr + vm->size > vaddr)
 			return svm;
 	}

 	return NULL;
 }

 void __init add_static_vm_early(struct static_vm *svm)
 {
 	struct static_vm *curr_svm;
 	struct vm_struct *vm;
 	void *vaddr;

 	vm = &svm->vm;
 	if (!vm_area_check_early(vm))
 		vm_area_add_early(vm);
 	vaddr = vm->addr;

 	list_for_each_entry(curr_svm, &static_vmlist, list) {
 		vm = &curr_svm->vm;

 		if (vm->addr > vaddr)
 			break;
 	}
 	list_add_tail(&svm->list, &curr_svm->list);
 }

 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_vmalloc_seq(struct mm_struct *mm)
 {
 	unsigned int seq;

 	do {
 		seq = init_mm.context.vmalloc_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.vmalloc_seq = seq;
 	} while (seq != init_mm.context.vmalloc_seq);
 }

 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
 /*
  * 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;
 	pud_t *pud;
 	pmd_t *pmdp;

 	flush_cache_vunmap(addr, end);
 	pgd = pgd_offset_k(addr);
 	pud = pud_offset(pgd, addr);
 	pmdp = pmd_offset(pud, addr);
 	do {
 		pmd_t pmd = *pmdp;

 		if (!pmd_none(pmd)) {
 			/*
 			 * Clear the PMD from the page table, and
 			 * increment the vmalloc sequence so others
 			 * notice this change.
 			 *
 			 * Note: this is still racy on SMP machines.
 			 */
 			pmd_clear(pmdp);
 			init_mm.context.vmalloc_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 += PMD_SIZE;
 		pmdp += 2;
 	} 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.vmalloc_seq != init_mm.context.vmalloc_seq)
 		__check_vmalloc_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;
 	pud_t *pud;
 	pmd_t *pmd;

 	/*
 	 * Remove and free any PTE-based mapping, and
 	 * sync the current kernel mapping.
 	 */
 	unmap_area_sections(virt, size);

 	pgd = pgd_offset_k(addr);
 	pud = pud_offset(pgd, addr);
 	pmd = pmd_offset(pud, addr);
 	do {
 		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 += PMD_SIZE;
 		pmd += 2;
 	} 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;
 	pud_t *pud;
 	pmd_t *pmd;

 	/*
 	 * Remove and free any PTE-based mapping, and
 	 * sync the current kernel mapping.
 	 */
 	unmap_area_sections(virt, size);

 	pgd = pgd_offset_k(virt);
 	pud = pud_offset(pgd, addr);
 	pmd = pmd_offset(pud, addr);
 	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[0] = __pmd(super_pmd_val);
 			pmd[1] = __pmd(super_pmd_val);
 			flush_pmd_entry(pmd);

 			addr += PMD_SIZE;
 			pmd += 2;
 		}

 		pfn += SUPERSECTION_SIZE >> PAGE_SHIFT;
 	} while (addr < end);

 	return 0;
 }
 #endif

 static 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;
 	phys_addr_t paddr = __pfn_to_phys(pfn);

 #ifndef CONFIG_ARM_LPAE
 	/*
 	 * High mappings must be supersection aligned
 	 */
 	if (pfn >= 0x100000 && (paddr & ~SUPERSECTION_MASK))
 		return NULL;
 #endif

 	type = get_mem_type(mtype);
 	if (!type)
 		return NULL;

 	/*
 	 * Page align the mapping size, taking account of any offset.
 	 */
 	size = PAGE_ALIGN(offset + size);

 	/*
 	 * Try to reuse one of the static mapping whenever possible.
 	 */
 	if (size && !(sizeof(phys_addr_t) == 4 && pfn >= 0x100000)) {
 		struct static_vm *svm;

 		svm = find_static_vm_paddr(paddr, size, mtype);
 		if (svm) {
 			addr = (unsigned long)svm->vm.addr;
 			addr += paddr - svm->vm.phys_addr;
 			return (void __iomem *) (offset + addr);
 		}
 	}

 	/*
 	 * Don't allow RAM to be mapped with mismatched attributes - this
 	 * causes problems with ARMv6+
 	 */
 	if (WARN_ON(pfn_valid(pfn) && mtype != MT_MEMORY_RW))
 		return NULL;

 	area = get_vm_area_caller(size, VM_IOREMAP, caller);
  	if (!area)
  		return NULL;
  	addr = (unsigned long)area->addr;
 	area->phys_addr = paddr;

 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
 	if (DOMAIN_IO == 0 &&
 	    (((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) ||
 	       cpu_is_xsc3()) && pfn >= 0x100000 &&
 	       !((paddr | size | addr) & ~SUPERSECTION_MASK)) {
 		area->flags |= VM_ARM_SECTION_MAPPING;
 		err = remap_area_supersections(addr, pfn, size, type);
 	} else if (!((paddr | 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, paddr,
 					 __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(phys_addr_t phys_addr, size_t size,
 	unsigned int mtype, void *caller)
 {
 	phys_addr_t 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 * (*arch_ioremap_caller)(phys_addr_t, size_t,
 				      unsigned int, void *) =
 	__arm_ioremap_caller;

 void __iomem *ioremap(resource_size_t res_cookie, size_t size)
 {
 	return arch_ioremap_caller(res_cookie, size, MT_DEVICE,
 				   __builtin_return_address(0));
 }
 EXPORT_SYMBOL(ioremap);

 void __iomem *ioremap_cache(resource_size_t res_cookie, size_t size)
 	__alias(ioremap_cached);

 void __iomem *ioremap_cached(resource_size_t res_cookie, size_t size)
 {
 	return arch_ioremap_caller(res_cookie, size, MT_DEVICE_CACHED,
 				   __builtin_return_address(0));
 }
 EXPORT_SYMBOL(ioremap_cache);
 EXPORT_SYMBOL(ioremap_cached);

 void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size)
 {
 	return arch_ioremap_caller(res_cookie, size, MT_DEVICE_WC,
 				   __builtin_return_address(0));
 }
 EXPORT_SYMBOL(ioremap_wc);

 /*
  * Remap an arbitrary physical address space into the kernel virtual
  * address space as memory. Needed when the kernel wants to execute
  * code in external memory. This is needed for reprogramming source
  * clocks that would affect normal memory for example. Please see
  * CONFIG_GENERIC_ALLOCATOR for allocating external memory.
  */
 void __iomem *
 __arm_ioremap_exec(phys_addr_t phys_addr, size_t size, bool cached)
 {
 	unsigned int mtype;

 	if (cached)
 		mtype = MT_MEMORY_RWX;
 	else
 		mtype = MT_MEMORY_RWX_NONCACHED;

 	return __arm_ioremap_caller(phys_addr, size, mtype,
 			__builtin_return_address(0));
 }

 void *arch_memremap_wb(phys_addr_t phys_addr, size_t size)
 {
 	return (__force void *)arch_ioremap_caller(phys_addr, size,
 						   MT_MEMORY_RW,
 						   __builtin_return_address(0));
 }

 void __iounmap(volatile void __iomem *io_addr)
 {
 	void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
 	struct static_vm *svm;

 	/* If this is a static mapping, we must leave it alone */
 	svm = find_static_vm_vaddr(addr);
 	if (svm)
 		return;

 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
 	{
 		struct vm_struct *vm;

 		vm = find_vm_area(addr);

 		/*
 		 * 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.
 		 */
 		if (vm && (vm->flags & VM_ARM_SECTION_MAPPING))
 			unmap_area_sections((unsigned long)vm->addr, vm->size);
 	}
 #endif

 	vunmap(addr);
 }

 void (*arch_iounmap)(volatile void __iomem *) = __iounmap;

 void iounmap(volatile void __iomem *cookie)
 {
 	arch_iounmap(cookie);
 }
 EXPORT_SYMBOL(iounmap);

 #ifdef CONFIG_PCI
 static int pci_ioremap_mem_type = MT_DEVICE;

 void pci_ioremap_set_mem_type(int mem_type)
 {
 	pci_ioremap_mem_type = mem_type;
 }

 int pci_ioremap_io(unsigned int offset, phys_addr_t phys_addr)
 {
 	BUG_ON(offset + SZ_64K > IO_SPACE_LIMIT);

 	return ioremap_page_range(PCI_IO_VIRT_BASE + offset,
 				  PCI_IO_VIRT_BASE + offset + SZ_64K,
 				  phys_addr,
 				  __pgprot(get_mem_type(pci_ioremap_mem_type)->prot_pte));
 }
 EXPORT_SYMBOL_GPL(pci_ioremap_io);
 #endif

 /*
  * Must be called after early_fixmap_init
  */
 void __init early_ioremap_init(void)
 {
 	early_ioremap_setup();
 }
	/*
	* 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 <linux/sizes.h>

	#include <asm/cp15.h>
	#include <asm/cputype.h>
	#include <asm/cacheflush.h>
	#include <asm/early_ioremap.h>
	#include <asm/mmu_context.h>
	#include <asm/pgalloc.h>
	#include <asm/tlbflush.h>
	#include <asm/system_info.h>

	#include <asm/mach/map.h>
	#include <asm/mach/pci.h>
	#include "mm.h"


	LIST_HEAD(static_vmlist);

	static struct static_vm *find_static_vm_paddr(phys_addr_t paddr,
	size_t size, unsigned int mtype)
	{
	struct static_vm *svm;
	struct vm_struct *vm;

	list_for_each_entry(svm, &static_vmlist, list) {
	vm = &svm->vm;
	if (!(vm->flags & VM_ARM_STATIC_MAPPING))
	continue;
	if ((vm->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype))
	continue;

	if (vm->phys_addr > paddr \|\|
	paddr + size - 1 > vm->phys_addr + vm->size - 1)
	continue;

	return svm;
	}

	return NULL;
	}

	struct static_vm find_static_vm_vaddr(void vaddr)
	{
	struct static_vm *svm;
	struct vm_struct *vm;

	list_for_each_entry(svm, &static_vmlist, list) {
	vm = &svm->vm;

	/* static_vmlist is ascending order */
	if (vm->addr > vaddr)
	break;

	if (vm->addr <= vaddr && vm->addr + vm->size > vaddr)
	return svm;
	}

	return NULL;
	}

	void __init add_static_vm_early(struct static_vm *svm)
	{
	struct static_vm *curr_svm;
	struct vm_struct *vm;
	void *vaddr;

	vm = &svm->vm;
	if (!vm_area_check_early(vm))
	vm_area_add_early(vm);
	vaddr = vm->addr;

	list_for_each_entry(curr_svm, &static_vmlist, list) {
	vm = &curr_svm->vm;

	if (vm->addr > vaddr)
	break;
	}
	list_add_tail(&svm->list, &curr_svm->list);
	}

	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_vmalloc_seq(struct mm_struct *mm)
	{
	unsigned int seq;

	do {
	seq = init_mm.context.vmalloc_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.vmalloc_seq = seq;
	} while (seq != init_mm.context.vmalloc_seq);
	}

	#if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
	/*
	* 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;
	pud_t *pud;
	pmd_t *pmdp;

	flush_cache_vunmap(addr, end);
	pgd = pgd_offset_k(addr);
	pud = pud_offset(pgd, addr);
	pmdp = pmd_offset(pud, addr);
	do {
	pmd_t pmd = *pmdp;

	if (!pmd_none(pmd)) {
	/*
	* Clear the PMD from the page table, and
	* increment the vmalloc sequence so others
	* notice this change.
	*
	* Note: this is still racy on SMP machines.
	*/
	pmd_clear(pmdp);
	init_mm.context.vmalloc_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 += PMD_SIZE;
	pmdp += 2;
	} 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.vmalloc_seq != init_mm.context.vmalloc_seq)
	__check_vmalloc_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;
	pud_t *pud;
	pmd_t *pmd;

	/*
	* Remove and free any PTE-based mapping, and
	* sync the current kernel mapping.
	*/
	unmap_area_sections(virt, size);

	pgd = pgd_offset_k(addr);
	pud = pud_offset(pgd, addr);
	pmd = pmd_offset(pud, addr);
	do {
	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 += PMD_SIZE;
	pmd += 2;
	} 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;
	pud_t *pud;
	pmd_t *pmd;

	/*
	* Remove and free any PTE-based mapping, and
	* sync the current kernel mapping.
	*/
	unmap_area_sections(virt, size);

	pgd = pgd_offset_k(virt);
	pud = pud_offset(pgd, addr);
	pmd = pmd_offset(pud, addr);
	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[0] = __pmd(super_pmd_val);
	pmd[1] = __pmd(super_pmd_val);
	flush_pmd_entry(pmd);

	addr += PMD_SIZE;
	pmd += 2;
	}

	pfn += SUPERSECTION_SIZE >> PAGE_SHIFT;
	} while (addr < end);

	return 0;
	}
	#endif

	static 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;
	phys_addr_t paddr = __pfn_to_phys(pfn);

	#ifndef CONFIG_ARM_LPAE
	/*
	* High mappings must be supersection aligned
	*/
	if (pfn >= 0x100000 && (paddr & ~SUPERSECTION_MASK))
	return NULL;
	#endif

	type = get_mem_type(mtype);
	if (!type)
	return NULL;

	/*
	* Page align the mapping size, taking account of any offset.
	*/
	size = PAGE_ALIGN(offset + size);

	/*
	* Try to reuse one of the static mapping whenever possible.
	*/
	if (size && !(sizeof(phys_addr_t) == 4 && pfn >= 0x100000)) {
	struct static_vm *svm;

	svm = find_static_vm_paddr(paddr, size, mtype);
	if (svm) {
	addr = (unsigned long)svm->vm.addr;
	addr += paddr - svm->vm.phys_addr;
	return (void __iomem *) (offset + addr);
	}
	}

	/*
	* Don't allow RAM to be mapped with mismatched attributes - this
	* causes problems with ARMv6+
	*/
	if (WARN_ON(pfn_valid(pfn) && mtype != MT_MEMORY_RW))
	return NULL;

	area = get_vm_area_caller(size, VM_IOREMAP, caller);
	if (!area)
	return NULL;
	addr = (unsigned long)area->addr;
	area->phys_addr = paddr;

	#if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
	if (DOMAIN_IO == 0 &&
	(((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) \|\|
	cpu_is_xsc3()) && pfn >= 0x100000 &&
	!((paddr \| size \| addr) & ~SUPERSECTION_MASK)) {
	area->flags \|= VM_ARM_SECTION_MAPPING;
	err = remap_area_supersections(addr, pfn, size, type);
	} else if (!((paddr \| 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, paddr,
	__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(phys_addr_t phys_addr, size_t size,
	unsigned int mtype, void *caller)
	{
	phys_addr_t 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 * (*arch_ioremap_caller)(phys_addr_t, size_t,
	unsigned int, void *) =
	__arm_ioremap_caller;

	void __iomem *ioremap(resource_size_t res_cookie, size_t size)
	{
	return arch_ioremap_caller(res_cookie, size, MT_DEVICE,
	__builtin_return_address(0));
	}
	EXPORT_SYMBOL(ioremap);

	void __iomem *ioremap_cache(resource_size_t res_cookie, size_t size)
	__alias(ioremap_cached);

	void __iomem *ioremap_cached(resource_size_t res_cookie, size_t size)
	{
	return arch_ioremap_caller(res_cookie, size, MT_DEVICE_CACHED,
	__builtin_return_address(0));
	}
	EXPORT_SYMBOL(ioremap_cache);
	EXPORT_SYMBOL(ioremap_cached);

	void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size)
	{
	return arch_ioremap_caller(res_cookie, size, MT_DEVICE_WC,
	__builtin_return_address(0));
	}
	EXPORT_SYMBOL(ioremap_wc);

	/*
	* Remap an arbitrary physical address space into the kernel virtual
	* address space as memory. Needed when the kernel wants to execute
	* code in external memory. This is needed for reprogramming source
	* clocks that would affect normal memory for example. Please see
	* CONFIG_GENERIC_ALLOCATOR for allocating external memory.
	*/
	void __iomem *
	__arm_ioremap_exec(phys_addr_t phys_addr, size_t size, bool cached)
	{
	unsigned int mtype;

	if (cached)
	mtype = MT_MEMORY_RWX;
	else
	mtype = MT_MEMORY_RWX_NONCACHED;

	return __arm_ioremap_caller(phys_addr, size, mtype,
	__builtin_return_address(0));
	}

	void *arch_memremap_wb(phys_addr_t phys_addr, size_t size)
	{
	return (__force void *)arch_ioremap_caller(phys_addr, size,
	MT_MEMORY_RW,
	__builtin_return_address(0));
	}

	void __iounmap(volatile void __iomem *io_addr)
	{
	void addr = (void )(PAGE_MASK & (unsigned long)io_addr);
	struct static_vm *svm;

	/* If this is a static mapping, we must leave it alone */
	svm = find_static_vm_vaddr(addr);
	if (svm)
	return;

	#if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
	{
	struct vm_struct *vm;

	vm = find_vm_area(addr);

	/*
	* 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.
	*/
	if (vm && (vm->flags & VM_ARM_SECTION_MAPPING))
	unmap_area_sections((unsigned long)vm->addr, vm->size);
	}
	#endif

	vunmap(addr);
	}

	void (arch_iounmap)(volatile void __iomem ) = __iounmap;

	void iounmap(volatile void __iomem *cookie)
	{
	arch_iounmap(cookie);
	}
	EXPORT_SYMBOL(iounmap);

	#ifdef CONFIG_PCI
	static int pci_ioremap_mem_type = MT_DEVICE;

	void pci_ioremap_set_mem_type(int mem_type)
	{
	pci_ioremap_mem_type = mem_type;
	}

	int pci_ioremap_io(unsigned int offset, phys_addr_t phys_addr)
	{
	BUG_ON(offset + SZ_64K > IO_SPACE_LIMIT);

	return ioremap_page_range(PCI_IO_VIRT_BASE + offset,
	PCI_IO_VIRT_BASE + offset + SZ_64K,
	phys_addr,
	__pgprot(get_mem_type(pci_ioremap_mem_type)->prot_pte));
	}
	EXPORT_SYMBOL_GPL(pci_ioremap_io);
	#endif

	/*
	* Must be called after early_fixmap_init
	*/
	void __init early_ioremap_init(void)
	{
	early_ioremap_setup();
	}