/*
   *  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/mmu_context.h>
  #include <asm/pgalloc.h>

  #include <asm/tlbflush.h>

  #include <asm/system_info.h>

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

  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);
  }

  #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 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 += 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.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;

  	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

  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;

  #ifndef CONFIG_ARM_LPAE

  	/*
  	 * High mappings must be supersection aligned
  	 */
  	if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~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.
  	 */
  	read_lock(&vmlist_lock);
  	for (area = vmlist; area; area = area->next) {
  		if (!size || (sizeof(phys_addr_t) == 4 && pfn >= 0x100000))
  			break;
  		if (!(area->flags & VM_ARM_STATIC_MAPPING))
  			continue;
  		if ((area->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype))
  			continue;
  		if (__phys_to_pfn(area->phys_addr) > pfn ||

  		    __pfn_to_phys(pfn) + size-1 > area->phys_addr + area->size-1)

  			continue;
  		/* we can drop the lock here as we know *area is static */
  		read_unlock(&vmlist_lock);
  		addr = (unsigned long)area->addr;
  		addr += __pfn_to_phys(pfn) - area->phys_addr;
  		return (void __iomem *) (offset + addr);
  	}
  	read_unlock(&vmlist_lock);
  
  	/*
  	 * Don't allow RAM to be mapped - this causes problems with ARMv6+
  	 */
  	if (WARN_ON(pfn_valid(pfn)))
  		return NULL;

  	area = get_vm_area_caller(size, VM_IOREMAP, caller);

   	if (!area)
   		return NULL;
   	addr = (unsigned long)area->addr;

  #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 &&

  	       !((__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 * (*arch_ioremap_caller)(unsigned long, size_t,
  				      unsigned int, void *) =
  	__arm_ioremap_caller;

  void __iomem *
  __arm_ioremap(unsigned long phys_addr, size_t size, unsigned int mtype)
  {

  	return arch_ioremap_caller(phys_addr, size, mtype,
  		__builtin_return_address(0));

  }

  EXPORT_SYMBOL(__arm_ioremap);

  /*
   * 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(unsigned long phys_addr, size_t size, bool cached)
  {
  	unsigned int mtype;
  
  	if (cached)
  		mtype = MT_MEMORY;
  	else
  		mtype = MT_MEMORY_NONCACHED;
  
  	return __arm_ioremap_caller(phys_addr, size, mtype,
  			__builtin_return_address(0));
  }

  void __iounmap(volatile void __iomem *io_addr)

  {

  	void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);

  	struct vm_struct *vm;

  	read_lock(&vmlist_lock);
  	for (vm = vmlist; vm; vm = vm->next) {

  		if (vm->addr > addr)

  			break;

  		if (!(vm->flags & VM_IOREMAP))
  			continue;
  		/* If this is a static mapping we must leave it alone */
  		if ((vm->flags & VM_ARM_STATIC_MAPPING) &&
  		    (vm->addr <= addr) && (vm->addr + vm->size > addr)) {
  			read_unlock(&vmlist_lock);
  			return;

  		}

  #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)

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

  	}

  	read_unlock(&vmlist_lock);

  	vunmap(addr);

  }

  
  void (*arch_iounmap)(volatile void __iomem *) = __iounmap;
  
  void __arm_iounmap(volatile void __iomem *io_addr)
  {
  	arch_iounmap(io_addr);
  }
  EXPORT_SYMBOL(__arm_iounmap);