1 /* 2 * linux/arch/arm/mm/ioremap.c 3 * 4 * Re-map IO memory to kernel address space so that we can access it. 5 * 6 * (C) Copyright 1995 1996 Linus Torvalds 7 * 8 * Hacked for ARM by Phil Blundell <philb@gnu.org> 9 * Hacked to allow all architectures to build, and various cleanups 10 * by Russell King 11 * 12 * This allows a driver to remap an arbitrary region of bus memory into 13 * virtual space. One should *only* use readl, writel, memcpy_toio and 14 * so on with such remapped areas. 15 * 16 * Because the ARM only has a 32-bit address space we can't address the 17 * whole of the (physical) PCI space at once. PCI huge-mode addressing 18 * allows us to circumvent this restriction by splitting PCI space into 19 * two 2GB chunks and mapping only one at a time into processor memory. 20 * We use MMU protection domains to trap any attempt to access the bank 21 * that is not currently mapped. (This isn't fully implemented yet.) 22 */ 23 #include <linux/module.h> 24 #include <linux/errno.h> 25 #include <linux/mm.h> 26 #include <linux/vmalloc.h> 27 #include <linux/io.h> 28 29 #include <asm/cputype.h> 30 #include <asm/cacheflush.h> 31 #include <asm/mmu_context.h> 32 #include <asm/pgalloc.h> 33 #include <asm/tlbflush.h> 34 #include <asm/sizes.h> 35 36 #include <asm/mach/map.h> 37 #include "mm.h" 38 39 /* 40 * Used by ioremap() and iounmap() code to mark (super)section-mapped 41 * I/O regions in vm_struct->flags field. 42 */ 43 #define VM_ARM_SECTION_MAPPING 0x80000000 44 45 int ioremap_page(unsigned long virt, unsigned long phys, 46 const struct mem_type *mtype) 47 { 48 return ioremap_page_range(virt, virt + PAGE_SIZE, phys, 49 __pgprot(mtype->prot_pte)); 50 } 51 EXPORT_SYMBOL(ioremap_page); 52 53 void __check_kvm_seq(struct mm_struct *mm) 54 { 55 unsigned int seq; 56 57 do { 58 seq = init_mm.context.kvm_seq; 59 memcpy(pgd_offset(mm, VMALLOC_START), 60 pgd_offset_k(VMALLOC_START), 61 sizeof(pgd_t) * (pgd_index(VMALLOC_END) - 62 pgd_index(VMALLOC_START))); 63 mm->context.kvm_seq = seq; 64 } while (seq != init_mm.context.kvm_seq); 65 } 66 67 #ifndef CONFIG_SMP 68 /* 69 * Section support is unsafe on SMP - If you iounmap and ioremap a region, 70 * the other CPUs will not see this change until their next context switch. 71 * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs 72 * which requires the new ioremap'd region to be referenced, the CPU will 73 * reference the _old_ region. 74 * 75 * Note that get_vm_area_caller() allocates a guard 4K page, so we need to 76 * mask the size back to 1MB aligned or we will overflow in the loop below. 77 */ 78 static void unmap_area_sections(unsigned long virt, unsigned long size) 79 { 80 unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1)); 81 pgd_t *pgd; 82 83 flush_cache_vunmap(addr, end); 84 pgd = pgd_offset_k(addr); 85 do { 86 pmd_t pmd, *pmdp = pmd_offset(pgd, addr); 87 88 pmd = *pmdp; 89 if (!pmd_none(pmd)) { 90 /* 91 * Clear the PMD from the page table, and 92 * increment the kvm sequence so others 93 * notice this change. 94 * 95 * Note: this is still racy on SMP machines. 96 */ 97 pmd_clear(pmdp); 98 init_mm.context.kvm_seq++; 99 100 /* 101 * Free the page table, if there was one. 102 */ 103 if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE) 104 pte_free_kernel(&init_mm, pmd_page_vaddr(pmd)); 105 } 106 107 addr += PGDIR_SIZE; 108 pgd++; 109 } while (addr < end); 110 111 /* 112 * Ensure that the active_mm is up to date - we want to 113 * catch any use-after-iounmap cases. 114 */ 115 if (current->active_mm->context.kvm_seq != init_mm.context.kvm_seq) 116 __check_kvm_seq(current->active_mm); 117 118 flush_tlb_kernel_range(virt, end); 119 } 120 121 static int 122 remap_area_sections(unsigned long virt, unsigned long pfn, 123 size_t size, const struct mem_type *type) 124 { 125 unsigned long addr = virt, end = virt + size; 126 pgd_t *pgd; 127 128 /* 129 * Remove and free any PTE-based mapping, and 130 * sync the current kernel mapping. 131 */ 132 unmap_area_sections(virt, size); 133 134 pgd = pgd_offset_k(addr); 135 do { 136 pmd_t *pmd = pmd_offset(pgd, addr); 137 138 pmd[0] = __pmd(__pfn_to_phys(pfn) | type->prot_sect); 139 pfn += SZ_1M >> PAGE_SHIFT; 140 pmd[1] = __pmd(__pfn_to_phys(pfn) | type->prot_sect); 141 pfn += SZ_1M >> PAGE_SHIFT; 142 flush_pmd_entry(pmd); 143 144 addr += PGDIR_SIZE; 145 pgd++; 146 } while (addr < end); 147 148 return 0; 149 } 150 151 static int 152 remap_area_supersections(unsigned long virt, unsigned long pfn, 153 size_t size, const struct mem_type *type) 154 { 155 unsigned long addr = virt, end = virt + size; 156 pgd_t *pgd; 157 158 /* 159 * Remove and free any PTE-based mapping, and 160 * sync the current kernel mapping. 161 */ 162 unmap_area_sections(virt, size); 163 164 pgd = pgd_offset_k(virt); 165 do { 166 unsigned long super_pmd_val, i; 167 168 super_pmd_val = __pfn_to_phys(pfn) | type->prot_sect | 169 PMD_SECT_SUPER; 170 super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20; 171 172 for (i = 0; i < 8; i++) { 173 pmd_t *pmd = pmd_offset(pgd, addr); 174 175 pmd[0] = __pmd(super_pmd_val); 176 pmd[1] = __pmd(super_pmd_val); 177 flush_pmd_entry(pmd); 178 179 addr += PGDIR_SIZE; 180 pgd++; 181 } 182 183 pfn += SUPERSECTION_SIZE >> PAGE_SHIFT; 184 } while (addr < end); 185 186 return 0; 187 } 188 #endif 189 190 void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn, 191 unsigned long offset, size_t size, unsigned int mtype, void *caller) 192 { 193 const struct mem_type *type; 194 int err; 195 unsigned long addr; 196 struct vm_struct * area; 197 198 /* 199 * High mappings must be supersection aligned 200 */ 201 if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SUPERSECTION_MASK)) 202 return NULL; 203 204 /* 205 * Don't allow RAM to be mapped - this causes problems with ARMv6+ 206 */ 207 if (WARN_ON(pfn_valid(pfn))) 208 return NULL; 209 210 type = get_mem_type(mtype); 211 if (!type) 212 return NULL; 213 214 /* 215 * Page align the mapping size, taking account of any offset. 216 */ 217 size = PAGE_ALIGN(offset + size); 218 219 area = get_vm_area_caller(size, VM_IOREMAP, caller); 220 if (!area) 221 return NULL; 222 addr = (unsigned long)area->addr; 223 224 #ifndef CONFIG_SMP 225 if (DOMAIN_IO == 0 && 226 (((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) || 227 cpu_is_xsc3()) && pfn >= 0x100000 && 228 !((__pfn_to_phys(pfn) | size | addr) & ~SUPERSECTION_MASK)) { 229 area->flags |= VM_ARM_SECTION_MAPPING; 230 err = remap_area_supersections(addr, pfn, size, type); 231 } else if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) { 232 area->flags |= VM_ARM_SECTION_MAPPING; 233 err = remap_area_sections(addr, pfn, size, type); 234 } else 235 #endif 236 err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn), 237 __pgprot(type->prot_pte)); 238 239 if (err) { 240 vunmap((void *)addr); 241 return NULL; 242 } 243 244 flush_cache_vmap(addr, addr + size); 245 return (void __iomem *) (offset + addr); 246 } 247 248 void __iomem *__arm_ioremap_caller(unsigned long phys_addr, size_t size, 249 unsigned int mtype, void *caller) 250 { 251 unsigned long last_addr; 252 unsigned long offset = phys_addr & ~PAGE_MASK; 253 unsigned long pfn = __phys_to_pfn(phys_addr); 254 255 /* 256 * Don't allow wraparound or zero size 257 */ 258 last_addr = phys_addr + size - 1; 259 if (!size || last_addr < phys_addr) 260 return NULL; 261 262 return __arm_ioremap_pfn_caller(pfn, offset, size, mtype, 263 caller); 264 } 265 266 /* 267 * Remap an arbitrary physical address space into the kernel virtual 268 * address space. Needed when the kernel wants to access high addresses 269 * directly. 270 * 271 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 272 * have to convert them into an offset in a page-aligned mapping, but the 273 * caller shouldn't need to know that small detail. 274 */ 275 void __iomem * 276 __arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size, 277 unsigned int mtype) 278 { 279 return __arm_ioremap_pfn_caller(pfn, offset, size, mtype, 280 __builtin_return_address(0)); 281 } 282 EXPORT_SYMBOL(__arm_ioremap_pfn); 283 284 void __iomem * 285 __arm_ioremap(unsigned long phys_addr, size_t size, unsigned int mtype) 286 { 287 return __arm_ioremap_caller(phys_addr, size, mtype, 288 __builtin_return_address(0)); 289 } 290 EXPORT_SYMBOL(__arm_ioremap); 291 292 void __iounmap(volatile void __iomem *io_addr) 293 { 294 void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr); 295 #ifndef CONFIG_SMP 296 struct vm_struct **p, *tmp; 297 298 /* 299 * If this is a section based mapping we need to handle it 300 * specially as the VM subsystem does not know how to handle 301 * such a beast. We need the lock here b/c we need to clear 302 * all the mappings before the area can be reclaimed 303 * by someone else. 304 */ 305 write_lock(&vmlist_lock); 306 for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) { 307 if ((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) { 308 if (tmp->flags & VM_ARM_SECTION_MAPPING) { 309 unmap_area_sections((unsigned long)tmp->addr, 310 tmp->size); 311 } 312 break; 313 } 314 } 315 write_unlock(&vmlist_lock); 316 #endif 317 318 vunmap(addr); 319 } 320 EXPORT_SYMBOL(__iounmap); 321