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 int ioremap_page(unsigned long virt, unsigned long phys, 43 const struct mem_type *mtype) 44 { 45 return ioremap_page_range(virt, virt + PAGE_SIZE, phys, 46 __pgprot(mtype->prot_pte)); 47 } 48 EXPORT_SYMBOL(ioremap_page); 49 50 void __check_kvm_seq(struct mm_struct *mm) 51 { 52 unsigned int seq; 53 54 do { 55 seq = init_mm.context.kvm_seq; 56 memcpy(pgd_offset(mm, VMALLOC_START), 57 pgd_offset_k(VMALLOC_START), 58 sizeof(pgd_t) * (pgd_index(VMALLOC_END) - 59 pgd_index(VMALLOC_START))); 60 mm->context.kvm_seq = seq; 61 } while (seq != init_mm.context.kvm_seq); 62 } 63 64 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) 65 /* 66 * Section support is unsafe on SMP - If you iounmap and ioremap a region, 67 * the other CPUs will not see this change until their next context switch. 68 * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs 69 * which requires the new ioremap'd region to be referenced, the CPU will 70 * reference the _old_ region. 71 * 72 * Note that get_vm_area_caller() allocates a guard 4K page, so we need to 73 * mask the size back to 1MB aligned or we will overflow in the loop below. 74 */ 75 static void unmap_area_sections(unsigned long virt, unsigned long size) 76 { 77 unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1)); 78 pgd_t *pgd; 79 pud_t *pud; 80 pmd_t *pmdp; 81 82 flush_cache_vunmap(addr, end); 83 pgd = pgd_offset_k(addr); 84 pud = pud_offset(pgd, addr); 85 pmdp = pmd_offset(pud, addr); 86 do { 87 pmd_t pmd = *pmdp; 88 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 += PMD_SIZE; 108 pmdp += 2; 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 pud_t *pud; 128 pmd_t *pmd; 129 130 /* 131 * Remove and free any PTE-based mapping, and 132 * sync the current kernel mapping. 133 */ 134 unmap_area_sections(virt, size); 135 136 pgd = pgd_offset_k(addr); 137 pud = pud_offset(pgd, addr); 138 pmd = pmd_offset(pud, addr); 139 do { 140 pmd[0] = __pmd(__pfn_to_phys(pfn) | type->prot_sect); 141 pfn += SZ_1M >> PAGE_SHIFT; 142 pmd[1] = __pmd(__pfn_to_phys(pfn) | type->prot_sect); 143 pfn += SZ_1M >> PAGE_SHIFT; 144 flush_pmd_entry(pmd); 145 146 addr += PMD_SIZE; 147 pmd += 2; 148 } while (addr < end); 149 150 return 0; 151 } 152 153 static int 154 remap_area_supersections(unsigned long virt, unsigned long pfn, 155 size_t size, const struct mem_type *type) 156 { 157 unsigned long addr = virt, end = virt + size; 158 pgd_t *pgd; 159 pud_t *pud; 160 pmd_t *pmd; 161 162 /* 163 * Remove and free any PTE-based mapping, and 164 * sync the current kernel mapping. 165 */ 166 unmap_area_sections(virt, size); 167 168 pgd = pgd_offset_k(virt); 169 pud = pud_offset(pgd, addr); 170 pmd = pmd_offset(pud, addr); 171 do { 172 unsigned long super_pmd_val, i; 173 174 super_pmd_val = __pfn_to_phys(pfn) | type->prot_sect | 175 PMD_SECT_SUPER; 176 super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20; 177 178 for (i = 0; i < 8; i++) { 179 pmd[0] = __pmd(super_pmd_val); 180 pmd[1] = __pmd(super_pmd_val); 181 flush_pmd_entry(pmd); 182 183 addr += PMD_SIZE; 184 pmd += 2; 185 } 186 187 pfn += SUPERSECTION_SIZE >> PAGE_SHIFT; 188 } while (addr < end); 189 190 return 0; 191 } 192 #endif 193 194 void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn, 195 unsigned long offset, size_t size, unsigned int mtype, void *caller) 196 { 197 const struct mem_type *type; 198 int err; 199 unsigned long addr; 200 struct vm_struct * area; 201 202 #ifndef CONFIG_ARM_LPAE 203 /* 204 * High mappings must be supersection aligned 205 */ 206 if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SUPERSECTION_MASK)) 207 return NULL; 208 #endif 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 /* 220 * Try to reuse one of the static mapping whenever possible. 221 */ 222 read_lock(&vmlist_lock); 223 for (area = vmlist; area; area = area->next) { 224 if (!size || (sizeof(phys_addr_t) == 4 && pfn >= 0x100000)) 225 break; 226 if (!(area->flags & VM_ARM_STATIC_MAPPING)) 227 continue; 228 if ((area->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype)) 229 continue; 230 if (__phys_to_pfn(area->phys_addr) > pfn || 231 __pfn_to_phys(pfn) + size-1 > area->phys_addr + area->size-1) 232 continue; 233 /* we can drop the lock here as we know *area is static */ 234 read_unlock(&vmlist_lock); 235 addr = (unsigned long)area->addr; 236 addr += __pfn_to_phys(pfn) - area->phys_addr; 237 return (void __iomem *) (offset + addr); 238 } 239 read_unlock(&vmlist_lock); 240 241 /* 242 * Don't allow RAM to be mapped - this causes problems with ARMv6+ 243 */ 244 if (WARN_ON(pfn_valid(pfn))) 245 return NULL; 246 247 area = get_vm_area_caller(size, VM_IOREMAP, caller); 248 if (!area) 249 return NULL; 250 addr = (unsigned long)area->addr; 251 252 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) 253 if (DOMAIN_IO == 0 && 254 (((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) || 255 cpu_is_xsc3()) && pfn >= 0x100000 && 256 !((__pfn_to_phys(pfn) | size | addr) & ~SUPERSECTION_MASK)) { 257 area->flags |= VM_ARM_SECTION_MAPPING; 258 err = remap_area_supersections(addr, pfn, size, type); 259 } else if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) { 260 area->flags |= VM_ARM_SECTION_MAPPING; 261 err = remap_area_sections(addr, pfn, size, type); 262 } else 263 #endif 264 err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn), 265 __pgprot(type->prot_pte)); 266 267 if (err) { 268 vunmap((void *)addr); 269 return NULL; 270 } 271 272 flush_cache_vmap(addr, addr + size); 273 return (void __iomem *) (offset + addr); 274 } 275 276 void __iomem *__arm_ioremap_caller(unsigned long phys_addr, size_t size, 277 unsigned int mtype, void *caller) 278 { 279 unsigned long last_addr; 280 unsigned long offset = phys_addr & ~PAGE_MASK; 281 unsigned long pfn = __phys_to_pfn(phys_addr); 282 283 /* 284 * Don't allow wraparound or zero size 285 */ 286 last_addr = phys_addr + size - 1; 287 if (!size || last_addr < phys_addr) 288 return NULL; 289 290 return __arm_ioremap_pfn_caller(pfn, offset, size, mtype, 291 caller); 292 } 293 294 /* 295 * Remap an arbitrary physical address space into the kernel virtual 296 * address space. Needed when the kernel wants to access high addresses 297 * directly. 298 * 299 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 300 * have to convert them into an offset in a page-aligned mapping, but the 301 * caller shouldn't need to know that small detail. 302 */ 303 void __iomem * 304 __arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size, 305 unsigned int mtype) 306 { 307 return __arm_ioremap_pfn_caller(pfn, offset, size, mtype, 308 __builtin_return_address(0)); 309 } 310 EXPORT_SYMBOL(__arm_ioremap_pfn); 311 312 void __iomem * (*arch_ioremap_caller)(unsigned long, size_t, 313 unsigned int, void *) = 314 __arm_ioremap_caller; 315 316 void __iomem * 317 __arm_ioremap(unsigned long phys_addr, size_t size, unsigned int mtype) 318 { 319 return arch_ioremap_caller(phys_addr, size, mtype, 320 __builtin_return_address(0)); 321 } 322 EXPORT_SYMBOL(__arm_ioremap); 323 324 /* 325 * Remap an arbitrary physical address space into the kernel virtual 326 * address space as memory. Needed when the kernel wants to execute 327 * code in external memory. This is needed for reprogramming source 328 * clocks that would affect normal memory for example. Please see 329 * CONFIG_GENERIC_ALLOCATOR for allocating external memory. 330 */ 331 void __iomem * 332 __arm_ioremap_exec(unsigned long phys_addr, size_t size, bool cached) 333 { 334 unsigned int mtype; 335 336 if (cached) 337 mtype = MT_MEMORY; 338 else 339 mtype = MT_MEMORY_NONCACHED; 340 341 return __arm_ioremap_caller(phys_addr, size, mtype, 342 __builtin_return_address(0)); 343 } 344 345 void __iounmap(volatile void __iomem *io_addr) 346 { 347 void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr); 348 struct vm_struct *vm; 349 350 read_lock(&vmlist_lock); 351 for (vm = vmlist; vm; vm = vm->next) { 352 if (vm->addr > addr) 353 break; 354 if (!(vm->flags & VM_IOREMAP)) 355 continue; 356 /* If this is a static mapping we must leave it alone */ 357 if ((vm->flags & VM_ARM_STATIC_MAPPING) && 358 (vm->addr <= addr) && (vm->addr + vm->size > addr)) { 359 read_unlock(&vmlist_lock); 360 return; 361 } 362 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) 363 /* 364 * If this is a section based mapping we need to handle it 365 * specially as the VM subsystem does not know how to handle 366 * such a beast. 367 */ 368 if ((vm->addr == addr) && 369 (vm->flags & VM_ARM_SECTION_MAPPING)) { 370 unmap_area_sections((unsigned long)vm->addr, vm->size); 371 break; 372 } 373 #endif 374 } 375 read_unlock(&vmlist_lock); 376 377 vunmap(addr); 378 } 379 380 void (*arch_iounmap)(volatile void __iomem *) = __iounmap; 381 382 void __arm_iounmap(volatile void __iomem *io_addr) 383 { 384 arch_iounmap(io_addr); 385 } 386 EXPORT_SYMBOL(__arm_iounmap); 387 388 #ifdef CONFIG_PCI 389 int pci_ioremap_io(unsigned int offset, phys_addr_t phys_addr) 390 { 391 BUG_ON(offset + SZ_64K > IO_SPACE_LIMIT); 392 393 return ioremap_page_range(PCI_IO_VIRT_BASE + offset, 394 PCI_IO_VIRT_BASE + offset + SZ_64K, 395 phys_addr, 396 __pgprot(get_mem_type(MT_DEVICE)->prot_pte)); 397 } 398 EXPORT_SYMBOL_GPL(pci_ioremap_io); 399 #endif 400