1/* 2 * arch/x86_64/mm/ioremap.c 3 * 4 * Re-map IO memory to kernel address space so that we can access it. 5 * This is needed for high PCI addresses that aren't mapped in the 6 * 640k-1MB IO memory area on PC's 7 * 8 * (C) Copyright 1995 1996 Linus Torvalds 9 */ 10 11#include <linux/vmalloc.h> 12#include <asm/io.h> 13#include <asm/pgalloc.h> 14 15static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size, 16 unsigned long phys_addr, unsigned long flags) 17{ 18 unsigned long end; 19 20 address &= ~PMD_MASK; 21 end = address + size; 22 if (end > PMD_SIZE) 23 end = PMD_SIZE; 24 if (address >= end) 25 BUG(); 26 do { 27 if (!pte_none(*pte)) { 28 printk("remap_area_pte: page already exists\n"); 29 BUG(); 30 } 31 set_pte(pte, mk_pte_phys(phys_addr, __pgprot(_PAGE_PRESENT | _PAGE_RW | 32 _PAGE_GLOBAL | _PAGE_DIRTY | _PAGE_ACCESSED | flags))); 33 address += PAGE_SIZE; 34 phys_addr += PAGE_SIZE; 35 pte++; 36 } while (address && (address < end)); 37} 38 39static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size, 40 unsigned long phys_addr, unsigned long flags) 41{ 42 unsigned long end; 43 44 address &= ~PGDIR_MASK; 45 end = address + size; 46 if (end > PGDIR_SIZE) 47 end = PGDIR_SIZE; 48 phys_addr -= address; 49 if (address >= end) 50 BUG(); 51 do { 52 pte_t * pte = pte_alloc(&init_mm, pmd, address); 53 if (!pte) 54 return -ENOMEM; 55 remap_area_pte(pte, address, end - address, address + phys_addr, flags); 56 address = (address + PMD_SIZE) & PMD_MASK; 57 pmd++; 58 } while (address && (address < end)); 59 return 0; 60} 61 62static int remap_area_pages(unsigned long address, unsigned long phys_addr, 63 unsigned long size, unsigned long flags) 64{ 65 int error; 66 pgd_t * dir; 67 unsigned long end = address + size; 68 69 phys_addr -= address; 70 dir = pgd_offset_k(address); 71 flush_cache_all(); 72 if (address >= end) 73 BUG(); 74 spin_lock(&init_mm.page_table_lock); 75 do { 76 pmd_t *pmd; 77 pmd = pmd_alloc(&init_mm, dir, address); 78 error = -ENOMEM; 79 if (!pmd) 80 break; 81 if (remap_area_pmd(pmd, address, end - address, 82 phys_addr + address, flags)) 83 break; 84 error = 0; 85 address = (address + PGDIR_SIZE) & PGDIR_MASK; 86 dir++; 87 } while (address && (address < end)); 88 spin_unlock(&init_mm.page_table_lock); 89 flush_tlb_all(); 90 return error; 91} 92 93/* 94 * Generic mapping function (not visible outside): 95 */ 96 97/* 98 * Remap an arbitrary physical address space into the kernel virtual 99 * address space. Needed when the kernel wants to access high addresses 100 * directly. 101 * 102 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 103 * have to convert them into an offset in a page-aligned mapping, but the 104 * caller shouldn't need to know that small detail. 105 */ 106void * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags) 107{ 108 void * addr; 109 struct vm_struct * area; 110 unsigned long offset, last_addr; 111 112 /* Don't allow wraparound or zero size */ 113 last_addr = phys_addr + size - 1; 114 if (!size || last_addr < phys_addr) 115 return NULL; 116 117 /* 118 * Don't remap the low PCI/ISA area, it's always mapped.. 119 */ 120 if (phys_addr >= 0xA0000 && last_addr < 0x100000) 121 return phys_to_virt(phys_addr); 122 123 /* 124 * Don't allow anybody to remap normal RAM that we're using.. 125 */ 126 if (phys_addr < virt_to_phys(high_memory)) { 127 char *t_addr, *t_end; 128 struct page *page; 129 130 t_addr = __va(phys_addr); 131 t_end = t_addr + (size - 1); 132 133#ifndef CONFIG_DISCONTIGMEM 134 for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++) 135 if(!PageReserved(page)) 136 return NULL; 137#endif 138 } 139 140 /* 141 * Mappings have to be page-aligned 142 */ 143 offset = phys_addr & ~PAGE_MASK; 144 phys_addr &= PAGE_MASK; 145 size = PAGE_ALIGN(last_addr) - phys_addr; 146 147 /* 148 * Ok, go for it.. 149 */ 150 area = get_vm_area(size, VM_IOREMAP); 151 if (!area) 152 return NULL; 153 addr = area->addr; 154 if (remap_area_pages(VMALLOC_VMADDR(addr), phys_addr, size, flags)) { 155 vfree(addr); 156 return NULL; 157 } 158 return (void *) (offset + (char *)addr); 159} 160 161void iounmap(void *addr) 162{ 163 if (addr > high_memory) 164 return vfree((void *) (PAGE_MASK & (unsigned long) addr)); 165} 166