1 /* 2 * arch/sh/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 * (C) Copyright 2005, 2006 Paul Mundt 10 * 11 * This file is subject to the terms and conditions of the GNU General 12 * Public License. See the file "COPYING" in the main directory of this 13 * archive for more details. 14 */ 15 #include <linux/vmalloc.h> 16 #include <linux/module.h> 17 #include <linux/mm.h> 18 #include <asm/io.h> 19 #include <asm/page.h> 20 #include <asm/pgalloc.h> 21 #include <asm/addrspace.h> 22 #include <asm/cacheflush.h> 23 #include <asm/tlbflush.h> 24 25 static inline void remap_area_pte(pte_t * pte, unsigned long address, 26 unsigned long size, unsigned long phys_addr, unsigned long flags) 27 { 28 unsigned long end; 29 unsigned long pfn; 30 pgprot_t pgprot = __pgprot(_PAGE_PRESENT | _PAGE_RW | 31 _PAGE_DIRTY | _PAGE_ACCESSED | 32 _PAGE_HW_SHARED | _PAGE_FLAGS_HARD | flags); 33 34 address &= ~PMD_MASK; 35 end = address + size; 36 if (end > PMD_SIZE) 37 end = PMD_SIZE; 38 if (address >= end) 39 BUG(); 40 pfn = phys_addr >> PAGE_SHIFT; 41 do { 42 if (!pte_none(*pte)) { 43 printk("remap_area_pte: page already exists\n"); 44 BUG(); 45 } 46 set_pte(pte, pfn_pte(pfn, pgprot)); 47 address += PAGE_SIZE; 48 pfn++; 49 pte++; 50 } while (address && (address < end)); 51 } 52 53 static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, 54 unsigned long size, unsigned long phys_addr, unsigned long flags) 55 { 56 unsigned long end; 57 58 address &= ~PGDIR_MASK; 59 end = address + size; 60 if (end > PGDIR_SIZE) 61 end = PGDIR_SIZE; 62 phys_addr -= address; 63 if (address >= end) 64 BUG(); 65 do { 66 pte_t * pte = pte_alloc_kernel(pmd, address); 67 if (!pte) 68 return -ENOMEM; 69 remap_area_pte(pte, address, end - address, address + phys_addr, flags); 70 address = (address + PMD_SIZE) & PMD_MASK; 71 pmd++; 72 } while (address && (address < end)); 73 return 0; 74 } 75 76 int remap_area_pages(unsigned long address, unsigned long phys_addr, 77 unsigned long size, unsigned long flags) 78 { 79 int error; 80 pgd_t * dir; 81 unsigned long end = address + size; 82 83 phys_addr -= address; 84 dir = pgd_offset_k(address); 85 flush_cache_all(); 86 if (address >= end) 87 BUG(); 88 do { 89 pud_t *pud; 90 pmd_t *pmd; 91 92 error = -ENOMEM; 93 94 pud = pud_alloc(&init_mm, dir, address); 95 if (!pud) 96 break; 97 pmd = pmd_alloc(&init_mm, pud, address); 98 if (!pmd) 99 break; 100 if (remap_area_pmd(pmd, address, end - address, 101 phys_addr + address, flags)) 102 break; 103 error = 0; 104 address = (address + PGDIR_SIZE) & PGDIR_MASK; 105 dir++; 106 } while (address && (address < end)); 107 flush_tlb_all(); 108 return error; 109 } 110 111 /* 112 * Remap an arbitrary physical address space into the kernel virtual 113 * address space. Needed when the kernel wants to access high addresses 114 * directly. 115 * 116 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 117 * have to convert them into an offset in a page-aligned mapping, but the 118 * caller shouldn't need to know that small detail. 119 */ 120 void __iomem *__ioremap(unsigned long phys_addr, unsigned long size, 121 unsigned long flags) 122 { 123 struct vm_struct * area; 124 unsigned long offset, last_addr, addr, orig_addr; 125 126 /* Don't allow wraparound or zero size */ 127 last_addr = phys_addr + size - 1; 128 if (!size || last_addr < phys_addr) 129 return NULL; 130 131 /* 132 * Don't remap the low PCI/ISA area, it's always mapped.. 133 */ 134 if (phys_addr >= 0xA0000 && last_addr < 0x100000) 135 return (void __iomem *)phys_to_virt(phys_addr); 136 137 /* 138 * Don't allow anybody to remap normal RAM that we're using.. 139 */ 140 if (phys_addr < virt_to_phys(high_memory)) 141 return NULL; 142 143 /* 144 * Mappings have to be page-aligned 145 */ 146 offset = phys_addr & ~PAGE_MASK; 147 phys_addr &= PAGE_MASK; 148 size = PAGE_ALIGN(last_addr+1) - phys_addr; 149 150 /* 151 * Ok, go for it.. 152 */ 153 area = get_vm_area(size, VM_IOREMAP); 154 if (!area) 155 return NULL; 156 area->phys_addr = phys_addr; 157 orig_addr = addr = (unsigned long)area->addr; 158 159 #ifdef CONFIG_32BIT 160 /* 161 * First try to remap through the PMB once a valid VMA has been 162 * established. Smaller allocations (or the rest of the size 163 * remaining after a PMB mapping due to the size not being 164 * perfectly aligned on a PMB size boundary) are then mapped 165 * through the UTLB using conventional page tables. 166 * 167 * PMB entries are all pre-faulted. 168 */ 169 if (unlikely(size >= 0x1000000)) { 170 unsigned long mapped = pmb_remap(addr, phys_addr, size, flags); 171 172 if (likely(mapped)) { 173 addr += mapped; 174 phys_addr += mapped; 175 size -= mapped; 176 } 177 } 178 #endif 179 180 if (likely(size)) 181 if (remap_area_pages(addr, phys_addr, size, flags)) { 182 vunmap((void *)orig_addr); 183 return NULL; 184 } 185 186 return (void __iomem *)(offset + (char *)orig_addr); 187 } 188 EXPORT_SYMBOL(__ioremap); 189 190 void __iounmap(void __iomem *addr) 191 { 192 unsigned long vaddr = (unsigned long __force)addr; 193 struct vm_struct *p; 194 195 if (PXSEG(vaddr) < P3SEG) 196 return; 197 198 #ifdef CONFIG_32BIT 199 /* 200 * Purge any PMB entries that may have been established for this 201 * mapping, then proceed with conventional VMA teardown. 202 * 203 * XXX: Note that due to the way that remove_vm_area() does 204 * matching of the resultant VMA, we aren't able to fast-forward 205 * the address past the PMB space until the end of the VMA where 206 * the page tables reside. As such, unmap_vm_area() will be 207 * forced to linearly scan over the area until it finds the page 208 * tables where PTEs that need to be unmapped actually reside, 209 * which is far from optimal. Perhaps we need to use a separate 210 * VMA for the PMB mappings? 211 * -- PFM. 212 */ 213 pmb_unmap(vaddr); 214 #endif 215 216 p = remove_vm_area((void *)(vaddr & PAGE_MASK)); 217 if (!p) { 218 printk(KERN_ERR "%s: bad address %p\n", __FUNCTION__, addr); 219 return; 220 } 221 222 kfree(p); 223 } 224 EXPORT_SYMBOL(__iounmap); 225