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 int ioremap_page(unsigned long virt, unsigned long phys, 40 const struct mem_type *mtype) 41 { 42 return ioremap_page_range(virt, virt + PAGE_SIZE, phys, 43 __pgprot(mtype->prot_pte)); 44 } 45 EXPORT_SYMBOL(ioremap_page); 46 47 void __check_kvm_seq(struct mm_struct *mm) 48 { 49 unsigned int seq; 50 51 do { 52 seq = init_mm.context.kvm_seq; 53 memcpy(pgd_offset(mm, VMALLOC_START), 54 pgd_offset_k(VMALLOC_START), 55 sizeof(pgd_t) * (pgd_index(VMALLOC_END) - 56 pgd_index(VMALLOC_START))); 57 mm->context.kvm_seq = seq; 58 } while (seq != init_mm.context.kvm_seq); 59 } 60 61 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) 62 /* 63 * Section support is unsafe on SMP - If you iounmap and ioremap a region, 64 * the other CPUs will not see this change until their next context switch. 65 * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs 66 * which requires the new ioremap'd region to be referenced, the CPU will 67 * reference the _old_ region. 68 * 69 * Note that get_vm_area_caller() allocates a guard 4K page, so we need to 70 * mask the size back to 1MB aligned or we will overflow in the loop below. 71 */ 72 static void unmap_area_sections(unsigned long virt, unsigned long size) 73 { 74 unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1)); 75 pgd_t *pgd; 76 pud_t *pud; 77 pmd_t *pmdp; 78 79 flush_cache_vunmap(addr, end); 80 pgd = pgd_offset_k(addr); 81 pud = pud_offset(pgd, addr); 82 pmdp = pmd_offset(pud, addr); 83 do { 84 pmd_t pmd = *pmdp; 85 86 if (!pmd_none(pmd)) { 87 /* 88 * Clear the PMD from the page table, and 89 * increment the kvm sequence so others 90 * notice this change. 91 * 92 * Note: this is still racy on SMP machines. 93 */ 94 pmd_clear(pmdp); 95 init_mm.context.kvm_seq++; 96 97 /* 98 * Free the page table, if there was one. 99 */ 100 if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE) 101 pte_free_kernel(&init_mm, pmd_page_vaddr(pmd)); 102 } 103 104 addr += PMD_SIZE; 105 pmdp += 2; 106 } while (addr < end); 107 108 /* 109 * Ensure that the active_mm is up to date - we want to 110 * catch any use-after-iounmap cases. 111 */ 112 if (current->active_mm->context.kvm_seq != init_mm.context.kvm_seq) 113 __check_kvm_seq(current->active_mm); 114 115 flush_tlb_kernel_range(virt, end); 116 } 117 118 static int 119 remap_area_sections(unsigned long virt, unsigned long pfn, 120 size_t size, const struct mem_type *type) 121 { 122 unsigned long addr = virt, end = virt + size; 123 pgd_t *pgd; 124 pud_t *pud; 125 pmd_t *pmd; 126 127 /* 128 * Remove and free any PTE-based mapping, and 129 * sync the current kernel mapping. 130 */ 131 unmap_area_sections(virt, size); 132 133 pgd = pgd_offset_k(addr); 134 pud = pud_offset(pgd, addr); 135 pmd = pmd_offset(pud, addr); 136 do { 137 pmd[0] = __pmd(__pfn_to_phys(pfn) | type->prot_sect); 138 pfn += SZ_1M >> PAGE_SHIFT; 139 pmd[1] = __pmd(__pfn_to_phys(pfn) | type->prot_sect); 140 pfn += SZ_1M >> PAGE_SHIFT; 141 flush_pmd_entry(pmd); 142 143 addr += PMD_SIZE; 144 pmd += 2; 145 } while (addr < end); 146 147 return 0; 148 } 149 150 static int 151 remap_area_supersections(unsigned long virt, unsigned long pfn, 152 size_t size, const struct mem_type *type) 153 { 154 unsigned long addr = virt, end = virt + size; 155 pgd_t *pgd; 156 pud_t *pud; 157 pmd_t *pmd; 158 159 /* 160 * Remove and free any PTE-based mapping, and 161 * sync the current kernel mapping. 162 */ 163 unmap_area_sections(virt, size); 164 165 pgd = pgd_offset_k(virt); 166 pud = pud_offset(pgd, addr); 167 pmd = pmd_offset(pud, addr); 168 do { 169 unsigned long super_pmd_val, i; 170 171 super_pmd_val = __pfn_to_phys(pfn) | type->prot_sect | 172 PMD_SECT_SUPER; 173 super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20; 174 175 for (i = 0; i < 8; i++) { 176 pmd[0] = __pmd(super_pmd_val); 177 pmd[1] = __pmd(super_pmd_val); 178 flush_pmd_entry(pmd); 179 180 addr += PMD_SIZE; 181 pmd += 2; 182 } 183 184 pfn += SUPERSECTION_SIZE >> PAGE_SHIFT; 185 } while (addr < end); 186 187 return 0; 188 } 189 #endif 190 191 void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn, 192 unsigned long offset, size_t size, unsigned int mtype, void *caller) 193 { 194 const struct mem_type *type; 195 int err; 196 unsigned long addr; 197 struct vm_struct * area; 198 199 #ifndef CONFIG_ARM_LPAE 200 /* 201 * High mappings must be supersection aligned 202 */ 203 if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SUPERSECTION_MASK)) 204 return NULL; 205 #endif 206 207 type = get_mem_type(mtype); 208 if (!type) 209 return NULL; 210 211 /* 212 * Page align the mapping size, taking account of any offset. 213 */ 214 size = PAGE_ALIGN(offset + size); 215 216 /* 217 * Try to reuse one of the static mapping whenever possible. 218 */ 219 read_lock(&vmlist_lock); 220 for (area = vmlist; area; area = area->next) { 221 if (!size || (sizeof(phys_addr_t) == 4 && pfn >= 0x100000)) 222 break; 223 if (!(area->flags & VM_ARM_STATIC_MAPPING)) 224 continue; 225 if ((area->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype)) 226 continue; 227 if (__phys_to_pfn(area->phys_addr) > pfn || 228 __pfn_to_phys(pfn) + size-1 > area->phys_addr + area->size-1) 229 continue; 230 /* we can drop the lock here as we know *area is static */ 231 read_unlock(&vmlist_lock); 232 addr = (unsigned long)area->addr; 233 addr += __pfn_to_phys(pfn) - area->phys_addr; 234 return (void __iomem *) (offset + addr); 235 } 236 read_unlock(&vmlist_lock); 237 238 /* 239 * Don't allow RAM to be mapped - this causes problems with ARMv6+ 240 */ 241 if (WARN_ON(pfn_valid(pfn))) 242 return NULL; 243 244 area = get_vm_area_caller(size, VM_IOREMAP, caller); 245 if (!area) 246 return NULL; 247 addr = (unsigned long)area->addr; 248 249 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) 250 if (DOMAIN_IO == 0 && 251 (((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) || 252 cpu_is_xsc3()) && pfn >= 0x100000 && 253 !((__pfn_to_phys(pfn) | size | addr) & ~SUPERSECTION_MASK)) { 254 area->flags |= VM_ARM_SECTION_MAPPING; 255 err = remap_area_supersections(addr, pfn, size, type); 256 } else if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) { 257 area->flags |= VM_ARM_SECTION_MAPPING; 258 err = remap_area_sections(addr, pfn, size, type); 259 } else 260 #endif 261 err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn), 262 __pgprot(type->prot_pte)); 263 264 if (err) { 265 vunmap((void *)addr); 266 return NULL; 267 } 268 269 flush_cache_vmap(addr, addr + size); 270 return (void __iomem *) (offset + addr); 271 } 272 273 void __iomem *__arm_ioremap_caller(unsigned long phys_addr, size_t size, 274 unsigned int mtype, void *caller) 275 { 276 unsigned long last_addr; 277 unsigned long offset = phys_addr & ~PAGE_MASK; 278 unsigned long pfn = __phys_to_pfn(phys_addr); 279 280 /* 281 * Don't allow wraparound or zero size 282 */ 283 last_addr = phys_addr + size - 1; 284 if (!size || last_addr < phys_addr) 285 return NULL; 286 287 return __arm_ioremap_pfn_caller(pfn, offset, size, mtype, 288 caller); 289 } 290 291 /* 292 * Remap an arbitrary physical address space into the kernel virtual 293 * address space. Needed when the kernel wants to access high addresses 294 * directly. 295 * 296 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 297 * have to convert them into an offset in a page-aligned mapping, but the 298 * caller shouldn't need to know that small detail. 299 */ 300 void __iomem * 301 __arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size, 302 unsigned int mtype) 303 { 304 return __arm_ioremap_pfn_caller(pfn, offset, size, mtype, 305 __builtin_return_address(0)); 306 } 307 EXPORT_SYMBOL(__arm_ioremap_pfn); 308 309 void __iomem * 310 __arm_ioremap(unsigned long phys_addr, size_t size, unsigned int mtype) 311 { 312 return __arm_ioremap_caller(phys_addr, size, mtype, 313 __builtin_return_address(0)); 314 } 315 EXPORT_SYMBOL(__arm_ioremap); 316 317 /* 318 * Remap an arbitrary physical address space into the kernel virtual 319 * address space as memory. Needed when the kernel wants to execute 320 * code in external memory. This is needed for reprogramming source 321 * clocks that would affect normal memory for example. Please see 322 * CONFIG_GENERIC_ALLOCATOR for allocating external memory. 323 */ 324 void __iomem * 325 __arm_ioremap_exec(unsigned long phys_addr, size_t size, bool cached) 326 { 327 unsigned int mtype; 328 329 if (cached) 330 mtype = MT_MEMORY; 331 else 332 mtype = MT_MEMORY_NONCACHED; 333 334 return __arm_ioremap_caller(phys_addr, size, mtype, 335 __builtin_return_address(0)); 336 } 337 338 void __iounmap(volatile void __iomem *io_addr) 339 { 340 void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr); 341 struct vm_struct *vm; 342 343 read_lock(&vmlist_lock); 344 for (vm = vmlist; vm; vm = vm->next) { 345 if (vm->addr > addr) 346 break; 347 if (!(vm->flags & VM_IOREMAP)) 348 continue; 349 /* If this is a static mapping we must leave it alone */ 350 if ((vm->flags & VM_ARM_STATIC_MAPPING) && 351 (vm->addr <= addr) && (vm->addr + vm->size > addr)) { 352 read_unlock(&vmlist_lock); 353 return; 354 } 355 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) 356 /* 357 * If this is a section based mapping we need to handle it 358 * specially as the VM subsystem does not know how to handle 359 * such a beast. 360 */ 361 if ((vm->addr == addr) && 362 (vm->flags & VM_ARM_SECTION_MAPPING)) { 363 unmap_area_sections((unsigned long)vm->addr, vm->size); 364 break; 365 } 366 #endif 367 } 368 read_unlock(&vmlist_lock); 369 370 vunmap(addr); 371 } 372 EXPORT_SYMBOL(__iounmap); 373