text: /*
   *  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;
  	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 - 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;
  	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)
  {
  	return arch_ioremap_caller(res_cookie, size, MT_DEVICE_CACHED,
  				   __builtin_return_address(0));
  }
  EXPORT_SYMBOL(ioremap_cache);
  
  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 __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();
  }
  