1/* 2 * arch/cris/mm/ioremap.c 3 * 4 * Re-map IO memory to kernel address space so that we can access it. 5 * Needed for memory-mapped I/O devices mapped outside our normal DRAM 6 * window (that is, all memory-mapped I/O devices). 7 * 8 * (C) Copyright 1995 1996 Linus Torvalds 9 * CRIS-port by Axis Communications AB 10 */ 11 12#include <linux/vmalloc.h> 13#include <asm/io.h> 14#include <asm/pgalloc.h> 15 16static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size, 17 unsigned long phys_addr, unsigned long flags) 18{ 19 unsigned long end; 20 21 address &= ~PMD_MASK; 22 end = address + size; 23 if (end > PMD_SIZE) 24 end = PMD_SIZE; 25 if (address >= end) 26 BUG(); 27 do { 28 if (!pte_none(*pte)) { 29 printk("remap_area_pte: page already exists\n"); 30 BUG(); 31 } 32 set_pte(pte, mk_pte_phys(phys_addr, __pgprot(_PAGE_PRESENT | __READABLE | 33 __WRITEABLE | _PAGE_GLOBAL | 34 _PAGE_KERNEL | flags))); 35 address += PAGE_SIZE; 36 phys_addr += PAGE_SIZE; 37 pte++; 38 } while (address && (address < end)); 39} 40 41static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size, 42 unsigned long phys_addr, unsigned long flags) 43{ 44 unsigned long end; 45 46 address &= ~PGDIR_MASK; 47 end = address + size; 48 if (end > PGDIR_SIZE) 49 end = PGDIR_SIZE; 50 phys_addr -= address; 51 if (address >= end) 52 BUG(); 53 do { 54 pte_t * pte = pte_alloc(&init_mm, pmd, address); 55 if (!pte) 56 return -ENOMEM; 57 remap_area_pte(pte, address, end - address, address + phys_addr, flags); 58 address = (address + PMD_SIZE) & PMD_MASK; 59 pmd++; 60 } while (address && (address < end)); 61 return 0; 62} 63 64static int remap_area_pages(unsigned long address, unsigned long phys_addr, 65 unsigned long size, unsigned long flags) 66{ 67 int error; 68 pgd_t * dir; 69 unsigned long end = address + size; 70 71 phys_addr -= address; 72 dir = pgd_offset(&init_mm, address); 73 flush_cache_all(); 74 if (address >= end) 75 BUG(); 76 spin_lock(&init_mm.page_table_lock); 77 do { 78 pmd_t *pmd; 79 pmd = pmd_alloc(&init_mm, dir, address); 80 error = -ENOMEM; 81 if (!pmd) 82 break; 83 if (remap_area_pmd(pmd, address, end - address, 84 phys_addr + address, flags)) 85 break; 86 error = 0; 87 address = (address + PGDIR_SIZE) & PGDIR_MASK; 88 dir++; 89 } while (address && (address < end)); 90 spin_unlock(&init_mm.page_table_lock); 91 flush_tlb_all(); 92 return error; 93} 94 95/* 96 * Generic mapping function (not visible outside): 97 */ 98 99/* 100 * Remap an arbitrary physical address space into the kernel virtual 101 * address space. Needed when the kernel wants to access high addresses 102 * directly. 103 * 104 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 105 * have to convert them into an offset in a page-aligned mapping, but the 106 * caller shouldn't need to know that small detail. 107 */ 108void * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags) 109{ 110 void * addr; 111 struct vm_struct * area; 112 unsigned long offset, last_addr; 113 114 /* Don't allow wraparound or zero size */ 115 last_addr = phys_addr + size - 1; 116 if (!size || last_addr < phys_addr) 117 return NULL; 118 119 120 /* 121 * Mappings have to be page-aligned 122 */ 123 offset = phys_addr & ~PAGE_MASK; 124 phys_addr &= PAGE_MASK; 125 size = PAGE_ALIGN(last_addr) - phys_addr; 126 127 /* 128 * Ok, go for it.. 129 */ 130 area = get_vm_area(size, VM_IOREMAP); 131 if (!area) 132 return NULL; 133 addr = area->addr; 134 if (remap_area_pages(VMALLOC_VMADDR(addr), phys_addr, size, flags)) { 135 vfree(addr); 136 return NULL; 137 } 138 return (void *) (offset + (char *)addr); 139} 140 141void iounmap(void *addr) 142{ 143 if (addr > high_memory) 144 return vfree((void *) (PAGE_MASK & (unsigned long) addr)); 145} 146