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 #include <linux/sizes.h> 29 30 #include <asm/cp15.h> 31 #include <asm/cputype.h> 32 #include <asm/cacheflush.h> 33 #include <asm/mmu_context.h> 34 #include <asm/pgalloc.h> 35 #include <asm/tlbflush.h> 36 #include <asm/system_info.h> 37 38 #include <asm/mach/map.h> 39 #include <asm/mach/pci.h> 40 #include "mm.h" 41 42 43 LIST_HEAD(static_vmlist); 44 45 static struct static_vm *find_static_vm_paddr(phys_addr_t paddr, 46 size_t size, unsigned int mtype) 47 { 48 struct static_vm *svm; 49 struct vm_struct *vm; 50 51 list_for_each_entry(svm, &static_vmlist, list) { 52 vm = &svm->vm; 53 if (!(vm->flags & VM_ARM_STATIC_MAPPING)) 54 continue; 55 if ((vm->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype)) 56 continue; 57 58 if (vm->phys_addr > paddr || 59 paddr + size - 1 > vm->phys_addr + vm->size - 1) 60 continue; 61 62 return svm; 63 } 64 65 return NULL; 66 } 67 68 struct static_vm *find_static_vm_vaddr(void *vaddr) 69 { 70 struct static_vm *svm; 71 struct vm_struct *vm; 72 73 list_for_each_entry(svm, &static_vmlist, list) { 74 vm = &svm->vm; 75 76 /* static_vmlist is ascending order */ 77 if (vm->addr > vaddr) 78 break; 79 80 if (vm->addr <= vaddr && vm->addr + vm->size > vaddr) 81 return svm; 82 } 83 84 return NULL; 85 } 86 87 void __init add_static_vm_early(struct static_vm *svm) 88 { 89 struct static_vm *curr_svm; 90 struct vm_struct *vm; 91 void *vaddr; 92 93 vm = &svm->vm; 94 vm_area_add_early(vm); 95 vaddr = vm->addr; 96 97 list_for_each_entry(curr_svm, &static_vmlist, list) { 98 vm = &curr_svm->vm; 99 100 if (vm->addr > vaddr) 101 break; 102 } 103 list_add_tail(&svm->list, &curr_svm->list); 104 } 105 106 int ioremap_page(unsigned long virt, unsigned long phys, 107 const struct mem_type *mtype) 108 { 109 return ioremap_page_range(virt, virt + PAGE_SIZE, phys, 110 __pgprot(mtype->prot_pte)); 111 } 112 EXPORT_SYMBOL(ioremap_page); 113 114 void __check_vmalloc_seq(struct mm_struct *mm) 115 { 116 unsigned int seq; 117 118 do { 119 seq = init_mm.context.vmalloc_seq; 120 memcpy(pgd_offset(mm, VMALLOC_START), 121 pgd_offset_k(VMALLOC_START), 122 sizeof(pgd_t) * (pgd_index(VMALLOC_END) - 123 pgd_index(VMALLOC_START))); 124 mm->context.vmalloc_seq = seq; 125 } while (seq != init_mm.context.vmalloc_seq); 126 } 127 128 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) 129 /* 130 * Section support is unsafe on SMP - If you iounmap and ioremap a region, 131 * the other CPUs will not see this change until their next context switch. 132 * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs 133 * which requires the new ioremap'd region to be referenced, the CPU will 134 * reference the _old_ region. 135 * 136 * Note that get_vm_area_caller() allocates a guard 4K page, so we need to 137 * mask the size back to 1MB aligned or we will overflow in the loop below. 138 */ 139 static void unmap_area_sections(unsigned long virt, unsigned long size) 140 { 141 unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1)); 142 pgd_t *pgd; 143 pud_t *pud; 144 pmd_t *pmdp; 145 146 flush_cache_vunmap(addr, end); 147 pgd = pgd_offset_k(addr); 148 pud = pud_offset(pgd, addr); 149 pmdp = pmd_offset(pud, addr); 150 do { 151 pmd_t pmd = *pmdp; 152 153 if (!pmd_none(pmd)) { 154 /* 155 * Clear the PMD from the page table, and 156 * increment the vmalloc sequence so others 157 * notice this change. 158 * 159 * Note: this is still racy on SMP machines. 160 */ 161 pmd_clear(pmdp); 162 init_mm.context.vmalloc_seq++; 163 164 /* 165 * Free the page table, if there was one. 166 */ 167 if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE) 168 pte_free_kernel(&init_mm, pmd_page_vaddr(pmd)); 169 } 170 171 addr += PMD_SIZE; 172 pmdp += 2; 173 } while (addr < end); 174 175 /* 176 * Ensure that the active_mm is up to date - we want to 177 * catch any use-after-iounmap cases. 178 */ 179 if (current->active_mm->context.vmalloc_seq != init_mm.context.vmalloc_seq) 180 __check_vmalloc_seq(current->active_mm); 181 182 flush_tlb_kernel_range(virt, end); 183 } 184 185 static int 186 remap_area_sections(unsigned long virt, unsigned long pfn, 187 size_t size, const struct mem_type *type) 188 { 189 unsigned long addr = virt, end = virt + size; 190 pgd_t *pgd; 191 pud_t *pud; 192 pmd_t *pmd; 193 194 /* 195 * Remove and free any PTE-based mapping, and 196 * sync the current kernel mapping. 197 */ 198 unmap_area_sections(virt, size); 199 200 pgd = pgd_offset_k(addr); 201 pud = pud_offset(pgd, addr); 202 pmd = pmd_offset(pud, addr); 203 do { 204 pmd[0] = __pmd(__pfn_to_phys(pfn) | type->prot_sect); 205 pfn += SZ_1M >> PAGE_SHIFT; 206 pmd[1] = __pmd(__pfn_to_phys(pfn) | type->prot_sect); 207 pfn += SZ_1M >> PAGE_SHIFT; 208 flush_pmd_entry(pmd); 209 210 addr += PMD_SIZE; 211 pmd += 2; 212 } while (addr < end); 213 214 return 0; 215 } 216 217 static int 218 remap_area_supersections(unsigned long virt, unsigned long pfn, 219 size_t size, const struct mem_type *type) 220 { 221 unsigned long addr = virt, end = virt + size; 222 pgd_t *pgd; 223 pud_t *pud; 224 pmd_t *pmd; 225 226 /* 227 * Remove and free any PTE-based mapping, and 228 * sync the current kernel mapping. 229 */ 230 unmap_area_sections(virt, size); 231 232 pgd = pgd_offset_k(virt); 233 pud = pud_offset(pgd, addr); 234 pmd = pmd_offset(pud, addr); 235 do { 236 unsigned long super_pmd_val, i; 237 238 super_pmd_val = __pfn_to_phys(pfn) | type->prot_sect | 239 PMD_SECT_SUPER; 240 super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20; 241 242 for (i = 0; i < 8; i++) { 243 pmd[0] = __pmd(super_pmd_val); 244 pmd[1] = __pmd(super_pmd_val); 245 flush_pmd_entry(pmd); 246 247 addr += PMD_SIZE; 248 pmd += 2; 249 } 250 251 pfn += SUPERSECTION_SIZE >> PAGE_SHIFT; 252 } while (addr < end); 253 254 return 0; 255 } 256 #endif 257 258 void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn, 259 unsigned long offset, size_t size, unsigned int mtype, void *caller) 260 { 261 const struct mem_type *type; 262 int err; 263 unsigned long addr; 264 struct vm_struct *area; 265 phys_addr_t paddr = __pfn_to_phys(pfn); 266 267 #ifndef CONFIG_ARM_LPAE 268 /* 269 * High mappings must be supersection aligned 270 */ 271 if (pfn >= 0x100000 && (paddr & ~SUPERSECTION_MASK)) 272 return NULL; 273 #endif 274 275 type = get_mem_type(mtype); 276 if (!type) 277 return NULL; 278 279 /* 280 * Page align the mapping size, taking account of any offset. 281 */ 282 size = PAGE_ALIGN(offset + size); 283 284 /* 285 * Try to reuse one of the static mapping whenever possible. 286 */ 287 if (size && !(sizeof(phys_addr_t) == 4 && pfn >= 0x100000)) { 288 struct static_vm *svm; 289 290 svm = find_static_vm_paddr(paddr, size, mtype); 291 if (svm) { 292 addr = (unsigned long)svm->vm.addr; 293 addr += paddr - svm->vm.phys_addr; 294 return (void __iomem *) (offset + addr); 295 } 296 } 297 298 /* 299 * Don't allow RAM to be mapped - this causes problems with ARMv6+ 300 */ 301 if (WARN_ON(pfn_valid(pfn))) 302 return NULL; 303 304 area = get_vm_area_caller(size, VM_IOREMAP, caller); 305 if (!area) 306 return NULL; 307 addr = (unsigned long)area->addr; 308 area->phys_addr = paddr; 309 310 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) 311 if (DOMAIN_IO == 0 && 312 (((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) || 313 cpu_is_xsc3()) && pfn >= 0x100000 && 314 !((paddr | size | addr) & ~SUPERSECTION_MASK)) { 315 area->flags |= VM_ARM_SECTION_MAPPING; 316 err = remap_area_supersections(addr, pfn, size, type); 317 } else if (!((paddr | size | addr) & ~PMD_MASK)) { 318 area->flags |= VM_ARM_SECTION_MAPPING; 319 err = remap_area_sections(addr, pfn, size, type); 320 } else 321 #endif 322 err = ioremap_page_range(addr, addr + size, paddr, 323 __pgprot(type->prot_pte)); 324 325 if (err) { 326 vunmap((void *)addr); 327 return NULL; 328 } 329 330 flush_cache_vmap(addr, addr + size); 331 return (void __iomem *) (offset + addr); 332 } 333 334 void __iomem *__arm_ioremap_caller(phys_addr_t phys_addr, size_t size, 335 unsigned int mtype, void *caller) 336 { 337 phys_addr_t last_addr; 338 unsigned long offset = phys_addr & ~PAGE_MASK; 339 unsigned long pfn = __phys_to_pfn(phys_addr); 340 341 /* 342 * Don't allow wraparound or zero size 343 */ 344 last_addr = phys_addr + size - 1; 345 if (!size || last_addr < phys_addr) 346 return NULL; 347 348 return __arm_ioremap_pfn_caller(pfn, offset, size, mtype, 349 caller); 350 } 351 352 /* 353 * Remap an arbitrary physical address space into the kernel virtual 354 * address space. Needed when the kernel wants to access high addresses 355 * directly. 356 * 357 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 358 * have to convert them into an offset in a page-aligned mapping, but the 359 * caller shouldn't need to know that small detail. 360 */ 361 void __iomem * 362 __arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size, 363 unsigned int mtype) 364 { 365 return __arm_ioremap_pfn_caller(pfn, offset, size, mtype, 366 __builtin_return_address(0)); 367 } 368 EXPORT_SYMBOL(__arm_ioremap_pfn); 369 370 void __iomem * (*arch_ioremap_caller)(phys_addr_t, size_t, 371 unsigned int, void *) = 372 __arm_ioremap_caller; 373 374 void __iomem * 375 __arm_ioremap(phys_addr_t phys_addr, size_t size, unsigned int mtype) 376 { 377 return arch_ioremap_caller(phys_addr, size, mtype, 378 __builtin_return_address(0)); 379 } 380 EXPORT_SYMBOL(__arm_ioremap); 381 382 /* 383 * Remap an arbitrary physical address space into the kernel virtual 384 * address space as memory. Needed when the kernel wants to execute 385 * code in external memory. This is needed for reprogramming source 386 * clocks that would affect normal memory for example. Please see 387 * CONFIG_GENERIC_ALLOCATOR for allocating external memory. 388 */ 389 void __iomem * 390 __arm_ioremap_exec(phys_addr_t phys_addr, size_t size, bool cached) 391 { 392 unsigned int mtype; 393 394 if (cached) 395 mtype = MT_MEMORY_RWX; 396 else 397 mtype = MT_MEMORY_RWX_NONCACHED; 398 399 return __arm_ioremap_caller(phys_addr, size, mtype, 400 __builtin_return_address(0)); 401 } 402 403 void __iounmap(volatile void __iomem *io_addr) 404 { 405 void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr); 406 struct static_vm *svm; 407 408 /* If this is a static mapping, we must leave it alone */ 409 svm = find_static_vm_vaddr(addr); 410 if (svm) 411 return; 412 413 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) 414 { 415 struct vm_struct *vm; 416 417 vm = find_vm_area(addr); 418 419 /* 420 * If this is a section based mapping we need to handle it 421 * specially as the VM subsystem does not know how to handle 422 * such a beast. 423 */ 424 if (vm && (vm->flags & VM_ARM_SECTION_MAPPING)) 425 unmap_area_sections((unsigned long)vm->addr, vm->size); 426 } 427 #endif 428 429 vunmap(addr); 430 } 431 432 void (*arch_iounmap)(volatile void __iomem *) = __iounmap; 433 434 void __arm_iounmap(volatile void __iomem *io_addr) 435 { 436 arch_iounmap(io_addr); 437 } 438 EXPORT_SYMBOL(__arm_iounmap); 439 440 #ifdef CONFIG_PCI 441 int pci_ioremap_io(unsigned int offset, phys_addr_t phys_addr) 442 { 443 BUG_ON(offset + SZ_64K > IO_SPACE_LIMIT); 444 445 return ioremap_page_range(PCI_IO_VIRT_BASE + offset, 446 PCI_IO_VIRT_BASE + offset + SZ_64K, 447 phys_addr, 448 __pgprot(get_mem_type(MT_DEVICE)->prot_pte)); 449 } 450 EXPORT_SYMBOL_GPL(pci_ioremap_io); 451 #endif 452