ioremap.c revision 15d07dc9c59eae51219c40253bdf920f62bb10f2
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/cp15.h> 30#include <asm/cputype.h> 31#include <asm/cacheflush.h> 32#include <asm/mmu_context.h> 33#include <asm/pgalloc.h> 34#include <asm/tlbflush.h> 35#include <asm/sizes.h> 36 37#include <asm/mach/map.h> 38#include "mm.h" 39 40int ioremap_page(unsigned long virt, unsigned long phys, 41 const struct mem_type *mtype) 42{ 43 return ioremap_page_range(virt, virt + PAGE_SIZE, phys, 44 __pgprot(mtype->prot_pte)); 45} 46EXPORT_SYMBOL(ioremap_page); 47 48void __check_kvm_seq(struct mm_struct *mm) 49{ 50 unsigned int seq; 51 52 do { 53 seq = init_mm.context.kvm_seq; 54 memcpy(pgd_offset(mm, VMALLOC_START), 55 pgd_offset_k(VMALLOC_START), 56 sizeof(pgd_t) * (pgd_index(VMALLOC_END) - 57 pgd_index(VMALLOC_START))); 58 mm->context.kvm_seq = seq; 59 } while (seq != init_mm.context.kvm_seq); 60} 61 62#if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) 63/* 64 * Section support is unsafe on SMP - If you iounmap and ioremap a region, 65 * the other CPUs will not see this change until their next context switch. 66 * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs 67 * which requires the new ioremap'd region to be referenced, the CPU will 68 * reference the _old_ region. 69 * 70 * Note that get_vm_area_caller() allocates a guard 4K page, so we need to 71 * mask the size back to 1MB aligned or we will overflow in the loop below. 72 */ 73static void unmap_area_sections(unsigned long virt, unsigned long size) 74{ 75 unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1)); 76 pgd_t *pgd; 77 pud_t *pud; 78 pmd_t *pmdp; 79 80 flush_cache_vunmap(addr, end); 81 pgd = pgd_offset_k(addr); 82 pud = pud_offset(pgd, addr); 83 pmdp = pmd_offset(pud, addr); 84 do { 85 pmd_t pmd = *pmdp; 86 87 if (!pmd_none(pmd)) { 88 /* 89 * Clear the PMD from the page table, and 90 * increment the kvm sequence so others 91 * notice this change. 92 * 93 * Note: this is still racy on SMP machines. 94 */ 95 pmd_clear(pmdp); 96 init_mm.context.kvm_seq++; 97 98 /* 99 * Free the page table, if there was one. 100 */ 101 if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE) 102 pte_free_kernel(&init_mm, pmd_page_vaddr(pmd)); 103 } 104 105 addr += PMD_SIZE; 106 pmdp += 2; 107 } while (addr < end); 108 109 /* 110 * Ensure that the active_mm is up to date - we want to 111 * catch any use-after-iounmap cases. 112 */ 113 if (current->active_mm->context.kvm_seq != init_mm.context.kvm_seq) 114 __check_kvm_seq(current->active_mm); 115 116 flush_tlb_kernel_range(virt, end); 117} 118 119static int 120remap_area_sections(unsigned long virt, unsigned long pfn, 121 size_t size, const struct mem_type *type) 122{ 123 unsigned long addr = virt, end = virt + size; 124 pgd_t *pgd; 125 pud_t *pud; 126 pmd_t *pmd; 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 pud = pud_offset(pgd, addr); 136 pmd = pmd_offset(pud, addr); 137 do { 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 += PMD_SIZE; 145 pmd += 2; 146 } while (addr < end); 147 148 return 0; 149} 150 151static int 152remap_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 pud_t *pud; 158 pmd_t *pmd; 159 160 /* 161 * Remove and free any PTE-based mapping, and 162 * sync the current kernel mapping. 163 */ 164 unmap_area_sections(virt, size); 165 166 pgd = pgd_offset_k(virt); 167 pud = pud_offset(pgd, addr); 168 pmd = pmd_offset(pud, addr); 169 do { 170 unsigned long super_pmd_val, i; 171 172 super_pmd_val = __pfn_to_phys(pfn) | type->prot_sect | 173 PMD_SECT_SUPER; 174 super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20; 175 176 for (i = 0; i < 8; i++) { 177 pmd[0] = __pmd(super_pmd_val); 178 pmd[1] = __pmd(super_pmd_val); 179 flush_pmd_entry(pmd); 180 181 addr += PMD_SIZE; 182 pmd += 2; 183 } 184 185 pfn += SUPERSECTION_SIZE >> PAGE_SHIFT; 186 } while (addr < end); 187 188 return 0; 189} 190#endif 191 192void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn, 193 unsigned long offset, size_t size, unsigned int mtype, void *caller) 194{ 195 const struct mem_type *type; 196 int err; 197 unsigned long addr; 198 struct vm_struct * area; 199 200#ifndef CONFIG_ARM_LPAE 201 /* 202 * High mappings must be supersection aligned 203 */ 204 if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SUPERSECTION_MASK)) 205 return NULL; 206#endif 207 208 type = get_mem_type(mtype); 209 if (!type) 210 return NULL; 211 212 /* 213 * Page align the mapping size, taking account of any offset. 214 */ 215 size = PAGE_ALIGN(offset + size); 216 217 /* 218 * Try to reuse one of the static mapping whenever possible. 219 */ 220 read_lock(&vmlist_lock); 221 for (area = vmlist; area; area = area->next) { 222 if (!size || (sizeof(phys_addr_t) == 4 && pfn >= 0x100000)) 223 break; 224 if (!(area->flags & VM_ARM_STATIC_MAPPING)) 225 continue; 226 if ((area->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype)) 227 continue; 228 if (__phys_to_pfn(area->phys_addr) > pfn || 229 __pfn_to_phys(pfn) + size-1 > area->phys_addr + area->size-1) 230 continue; 231 /* we can drop the lock here as we know *area is static */ 232 read_unlock(&vmlist_lock); 233 addr = (unsigned long)area->addr; 234 addr += __pfn_to_phys(pfn) - area->phys_addr; 235 return (void __iomem *) (offset + addr); 236 } 237 read_unlock(&vmlist_lock); 238 239 /* 240 * Don't allow RAM to be mapped - this causes problems with ARMv6+ 241 */ 242 if (WARN_ON(pfn_valid(pfn))) 243 return NULL; 244 245 area = get_vm_area_caller(size, VM_IOREMAP, caller); 246 if (!area) 247 return NULL; 248 addr = (unsigned long)area->addr; 249 250#if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) 251 if (DOMAIN_IO == 0 && 252 (((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) || 253 cpu_is_xsc3()) && pfn >= 0x100000 && 254 !((__pfn_to_phys(pfn) | size | addr) & ~SUPERSECTION_MASK)) { 255 area->flags |= VM_ARM_SECTION_MAPPING; 256 err = remap_area_supersections(addr, pfn, size, type); 257 } else if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) { 258 area->flags |= VM_ARM_SECTION_MAPPING; 259 err = remap_area_sections(addr, pfn, size, type); 260 } else 261#endif 262 err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn), 263 __pgprot(type->prot_pte)); 264 265 if (err) { 266 vunmap((void *)addr); 267 return NULL; 268 } 269 270 flush_cache_vmap(addr, addr + size); 271 return (void __iomem *) (offset + addr); 272} 273 274void __iomem *__arm_ioremap_caller(unsigned long phys_addr, size_t size, 275 unsigned int mtype, void *caller) 276{ 277 unsigned long last_addr; 278 unsigned long offset = phys_addr & ~PAGE_MASK; 279 unsigned long pfn = __phys_to_pfn(phys_addr); 280 281 /* 282 * Don't allow wraparound or zero size 283 */ 284 last_addr = phys_addr + size - 1; 285 if (!size || last_addr < phys_addr) 286 return NULL; 287 288 return __arm_ioremap_pfn_caller(pfn, offset, size, mtype, 289 caller); 290} 291 292/* 293 * Remap an arbitrary physical address space into the kernel virtual 294 * address space. Needed when the kernel wants to access high addresses 295 * directly. 296 * 297 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 298 * have to convert them into an offset in a page-aligned mapping, but the 299 * caller shouldn't need to know that small detail. 300 */ 301void __iomem * 302__arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size, 303 unsigned int mtype) 304{ 305 return __arm_ioremap_pfn_caller(pfn, offset, size, mtype, 306 __builtin_return_address(0)); 307} 308EXPORT_SYMBOL(__arm_ioremap_pfn); 309 310void __iomem * 311__arm_ioremap(unsigned long phys_addr, size_t size, unsigned int mtype) 312{ 313 return __arm_ioremap_caller(phys_addr, size, mtype, 314 __builtin_return_address(0)); 315} 316EXPORT_SYMBOL(__arm_ioremap); 317 318/* 319 * Remap an arbitrary physical address space into the kernel virtual 320 * address space as memory. Needed when the kernel wants to execute 321 * code in external memory. This is needed for reprogramming source 322 * clocks that would affect normal memory for example. Please see 323 * CONFIG_GENERIC_ALLOCATOR for allocating external memory. 324 */ 325void __iomem * 326__arm_ioremap_exec(unsigned long phys_addr, size_t size, bool cached) 327{ 328 unsigned int mtype; 329 330 if (cached) 331 mtype = MT_MEMORY; 332 else 333 mtype = MT_MEMORY_NONCACHED; 334 335 return __arm_ioremap_caller(phys_addr, size, mtype, 336 __builtin_return_address(0)); 337} 338 339void __iounmap(volatile void __iomem *io_addr) 340{ 341 void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr); 342 struct vm_struct *vm; 343 344 read_lock(&vmlist_lock); 345 for (vm = vmlist; vm; vm = vm->next) { 346 if (vm->addr > addr) 347 break; 348 if (!(vm->flags & VM_IOREMAP)) 349 continue; 350 /* If this is a static mapping we must leave it alone */ 351 if ((vm->flags & VM_ARM_STATIC_MAPPING) && 352 (vm->addr <= addr) && (vm->addr + vm->size > addr)) { 353 read_unlock(&vmlist_lock); 354 return; 355 } 356#if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) 357 /* 358 * If this is a section based mapping we need to handle it 359 * specially as the VM subsystem does not know how to handle 360 * such a beast. 361 */ 362 if ((vm->addr == addr) && 363 (vm->flags & VM_ARM_SECTION_MAPPING)) { 364 unmap_area_sections((unsigned long)vm->addr, vm->size); 365 break; 366 } 367#endif 368 } 369 read_unlock(&vmlist_lock); 370 371 vunmap(addr); 372} 373EXPORT_SYMBOL(__iounmap); 374