arch/arm/mm/ioremap.c

   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/early_ioremap.h>
  34 #include <asm/mmu_context.h>
  35 #include <asm/pgalloc.h>
  36 #include <asm/tlbflush.h>
  37 #include <asm/system_info.h>
  38
  39 #include <asm/mach/map.h>
  40 #include <asm/mach/pci.h>
  41 #include "mm.h"
  42
  43
  44 LIST_HEAD(static_vmlist);
  45
  46 static struct static_vm *find_static_vm_paddr(phys_addr_t paddr,
  47                         size_t size, unsigned int mtype)
  48 {
  49         struct static_vm *svm;
  50         struct vm_struct *vm;
  51
  52         list_for_each_entry(svm, &static_vmlist, list) {
  53                 vm = &svm->vm;
  54                 if (!(vm->flags & VM_ARM_STATIC_MAPPING))
  55                         continue;
  56                 if ((vm->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype))
  57                         continue;
  58
  59                 if (vm->phys_addr > paddr ||
  60                         paddr + size - 1 > vm->phys_addr + vm->size - 1)
  61                         continue;
  62
  63                 return svm;
  64         }
  65
  66         return NULL;
  67 }
  68
  69 struct static_vm *find_static_vm_vaddr(void *vaddr)
  70 {
  71         struct static_vm *svm;
  72         struct vm_struct *vm;
  73
  74         list_for_each_entry(svm, &static_vmlist, list) {
  75                 vm = &svm->vm;
  76
  77                 /* static_vmlist is ascending order */
  78                 if (vm->addr > vaddr)
  79                         break;
  80
  81                 if (vm->addr <= vaddr && vm->addr + vm->size > vaddr)
  82                         return svm;
  83         }
  84
  85         return NULL;
  86 }
  87
  88 void __init add_static_vm_early(struct static_vm *svm)
  89 {
  90         struct static_vm *curr_svm;
  91         struct vm_struct *vm;
  92         void *vaddr;
  93
  94         vm = &svm->vm;
  95         vm_area_add_early(vm);
  96         vaddr = vm->addr;
  97
  98         list_for_each_entry(curr_svm, &static_vmlist, list) {
  99                 vm = &curr_svm->vm;
 100
 101                 if (vm->addr > vaddr)
 102                         break;
 103         }
 104         list_add_tail(&svm->list, &curr_svm->list);
 105 }
 106
 107 int ioremap_page(unsigned long virt, unsigned long phys,
 108                  const struct mem_type *mtype)
 109 {
 110         return ioremap_page_range(virt, virt + PAGE_SIZE, phys,
 111                                   __pgprot(mtype->prot_pte));
 112 }
 113 EXPORT_SYMBOL(ioremap_page);
 114
 115 void __check_vmalloc_seq(struct mm_struct *mm)
 116 {
 117         unsigned int seq;
 118
 119         do {
 120                 seq = init_mm.context.vmalloc_seq;
 121                 memcpy(pgd_offset(mm, VMALLOC_START),
 122                        pgd_offset_k(VMALLOC_START),
 123                        sizeof(pgd_t) * (pgd_index(VMALLOC_END) -
 124                                         pgd_index(VMALLOC_START)));
 125                 mm->context.vmalloc_seq = seq;
 126         } while (seq != init_mm.context.vmalloc_seq);
 127 }
 128
 129 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
 130 /*
 131  * Section support is unsafe on SMP - If you iounmap and ioremap a region,
 132  * the other CPUs will not see this change until their next context switch.
 133  * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
 134  * which requires the new ioremap'd region to be referenced, the CPU will
 135  * reference the _old_ region.
 136  *
 137  * Note that get_vm_area_caller() allocates a guard 4K page, so we need to
 138  * mask the size back to 1MB aligned or we will overflow in the loop below.
 139  */
 140 static void unmap_area_sections(unsigned long virt, unsigned long size)
 141 {
 142         unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1));
 143         pgd_t *pgd;
 144         pud_t *pud;
 145         pmd_t *pmdp;
 146
 147         flush_cache_vunmap(addr, end);
 148         pgd = pgd_offset_k(addr);
 149         pud = pud_offset(pgd, addr);
 150         pmdp = pmd_offset(pud, addr);
 151         do {
 152                 pmd_t pmd = *pmdp;
 153
 154                 if (!pmd_none(pmd)) {
 155                         /*
 156                          * Clear the PMD from the page table, and
 157                          * increment the vmalloc sequence so others
 158                          * notice this change.
 159                          *
 160                          * Note: this is still racy on SMP machines.
 161                          */
 162                         pmd_clear(pmdp);
 163                         init_mm.context.vmalloc_seq++;
 164
 165                         /*
 166                          * Free the page table, if there was one.
 167                          */
 168                         if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
 169                                 pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
 170                 }
 171
 172                 addr += PMD_SIZE;
 173                 pmdp += 2;
 174         } while (addr < end);
 175
 176         /*
 177          * Ensure that the active_mm is up to date - we want to
 178          * catch any use-after-iounmap cases.
 179          */
 180         if (current->active_mm->context.vmalloc_seq != init_mm.context.vmalloc_seq)
 181                 __check_vmalloc_seq(current->active_mm);
 182
 183         flush_tlb_kernel_range(virt, end);
 184 }
 185
 186 static int
 187 remap_area_sections(unsigned long virt, unsigned long pfn,
 188                     size_t size, const struct mem_type *type)
 189 {
 190         unsigned long addr = virt, end = virt + size;
 191         pgd_t *pgd;
 192         pud_t *pud;
 193         pmd_t *pmd;
 194
 195         /*
 196          * Remove and free any PTE-based mapping, and
 197          * sync the current kernel mapping.
 198          */
 199         unmap_area_sections(virt, size);
 200
 201         pgd = pgd_offset_k(addr);
 202         pud = pud_offset(pgd, addr);
 203         pmd = pmd_offset(pud, addr);
 204         do {
 205                 pmd[0] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
 206                 pfn += SZ_1M >> PAGE_SHIFT;
 207                 pmd[1] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
 208                 pfn += SZ_1M >> PAGE_SHIFT;
 209                 flush_pmd_entry(pmd);
 210
 211                 addr += PMD_SIZE;
 212                 pmd += 2;
 213         } while (addr < end);
 214
 215         return 0;
 216 }
 217
 218 static int
 219 remap_area_supersections(unsigned long virt, unsigned long pfn,
 220                          size_t size, const struct mem_type *type)
 221 {
 222         unsigned long addr = virt, end = virt + size;
 223         pgd_t *pgd;
 224         pud_t *pud;
 225         pmd_t *pmd;
 226
 227         /*
 228          * Remove and free any PTE-based mapping, and
 229          * sync the current kernel mapping.
 230          */
 231         unmap_area_sections(virt, size);
 232
 233         pgd = pgd_offset_k(virt);
 234         pud = pud_offset(pgd, addr);
 235         pmd = pmd_offset(pud, addr);
 236         do {
 237                 unsigned long super_pmd_val, i;
 238
 239                 super_pmd_val = __pfn_to_phys(pfn) | type->prot_sect |
 240                                 PMD_SECT_SUPER;
 241                 super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20;
 242
 243                 for (i = 0; i < 8; i++) {
 244                         pmd[0] = __pmd(super_pmd_val);
 245                         pmd[1] = __pmd(super_pmd_val);
 246                         flush_pmd_entry(pmd);
 247
 248                         addr += PMD_SIZE;
 249                         pmd += 2;
 250                 }
 251
 252                 pfn += SUPERSECTION_SIZE >> PAGE_SHIFT;
 253         } while (addr < end);
 254
 255         return 0;
 256 }
 257 #endif
 258
 259 static void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn,
 260         unsigned long offset, size_t size, unsigned int mtype, void *caller)
 261 {
 262         const struct mem_type *type;
 263         int err;
 264         unsigned long addr;
 265         struct vm_struct *area;
 266         phys_addr_t paddr = __pfn_to_phys(pfn);
 267
 268 #ifndef CONFIG_ARM_LPAE
 269         /*
 270          * High mappings must be supersection aligned
 271          */
 272         if (pfn >= 0x100000 && (paddr & ~SUPERSECTION_MASK))
 273                 return NULL;
 274 #endif
 275
 276         type = get_mem_type(mtype);
 277         if (!type)
 278                 return NULL;
 279
 280         /*
 281          * Page align the mapping size, taking account of any offset.
 282          */
 283         size = PAGE_ALIGN(offset + size);
 284
 285         /*
 286          * Try to reuse one of the static mapping whenever possible.
 287          */
 288         if (size && !(sizeof(phys_addr_t) == 4 && pfn >= 0x100000)) {
 289                 struct static_vm *svm;
 290
 291                 svm = find_static_vm_paddr(paddr, size, mtype);
 292                 if (svm) {
 293                         addr = (unsigned long)svm->vm.addr;
 294                         addr += paddr - svm->vm.phys_addr;
 295                         return (void __iomem *) (offset + addr);
 296                 }
 297         }
 298
 299         /*
 300          * Don't allow RAM to be mapped with mismatched attributes - this
 301          * causes problems with ARMv6+
 302          */
 303         if (WARN_ON(pfn_valid(pfn) && mtype != MT_MEMORY_RW))
 304                 return NULL;
 305
 306         area = get_vm_area_caller(size, VM_IOREMAP, caller);
 307         if (!area)
 308                 return NULL;
 309         addr = (unsigned long)area->addr;
 310         area->phys_addr = paddr;
 311
 312 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
 313         if (DOMAIN_IO == 0 &&
 314             (((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) ||
 315                cpu_is_xsc3()) && pfn >= 0x100000 &&
 316                !((paddr | size | addr) & ~SUPERSECTION_MASK)) {
 317                 area->flags |= VM_ARM_SECTION_MAPPING;
 318                 err = remap_area_supersections(addr, pfn, size, type);
 319         } else if (!((paddr | size | addr) & ~PMD_MASK)) {
 320                 area->flags |= VM_ARM_SECTION_MAPPING;
 321                 err = remap_area_sections(addr, pfn, size, type);
 322         } else
 323 #endif
 324                 err = ioremap_page_range(addr, addr + size, paddr,
 325                                          __pgprot(type->prot_pte));
 326
 327         if (err) {
 328                 vunmap((void *)addr);
 329                 return NULL;
 330         }
 331
 332         flush_cache_vmap(addr, addr + size);
 333         return (void __iomem *) (offset + addr);
 334 }
 335
 336 void __iomem *__arm_ioremap_caller(phys_addr_t phys_addr, size_t size,
 337         unsigned int mtype, void *caller)
 338 {
 339         phys_addr_t last_addr;
 340         unsigned long offset = phys_addr & ~PAGE_MASK;
 341         unsigned long pfn = __phys_to_pfn(phys_addr);
 342
 343         /*
 344          * Don't allow wraparound or zero size
 345          */
 346         last_addr = phys_addr + size - 1;
 347         if (!size || last_addr < phys_addr)
 348                 return NULL;
 349
 350         return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
 351                         caller);
 352 }
 353
 354 /*
 355  * Remap an arbitrary physical address space into the kernel virtual
 356  * address space. Needed when the kernel wants to access high addresses
 357  * directly.
 358  *
 359  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 360  * have to convert them into an offset in a page-aligned mapping, but the
 361  * caller shouldn't need to know that small detail.
 362  */
 363 void __iomem *
 364 __arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
 365                   unsigned int mtype)
 366 {
 367         return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
 368                                         __builtin_return_address(0));
 369 }
 370 EXPORT_SYMBOL(__arm_ioremap_pfn);
 371
 372 void __iomem * (*arch_ioremap_caller)(phys_addr_t, size_t,
 373                                       unsigned int, void *) =
 374         __arm_ioremap_caller;
 375
 376 void __iomem *ioremap(resource_size_t res_cookie, size_t size)
 377 {
 378         return arch_ioremap_caller(res_cookie, size, MT_DEVICE,
 379                                    __builtin_return_address(0));
 380 }
 381 EXPORT_SYMBOL(ioremap);
 382
 383 void __iomem *ioremap_cache(resource_size_t res_cookie, size_t size)
 384         __alias(ioremap_cached);
 385
 386 void __iomem *ioremap_cached(resource_size_t res_cookie, size_t size)
 387 {
 388         return arch_ioremap_caller(res_cookie, size, MT_DEVICE_CACHED,
 389                                    __builtin_return_address(0));
 390 }
 391 EXPORT_SYMBOL(ioremap_cache);
 392 EXPORT_SYMBOL(ioremap_cached);
 393
 394 void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size)
 395 {
 396         return arch_ioremap_caller(res_cookie, size, MT_DEVICE_WC,
 397                                    __builtin_return_address(0));
 398 }
 399 EXPORT_SYMBOL(ioremap_wc);
 400
 401 /*
 402  * Remap an arbitrary physical address space into the kernel virtual
 403  * address space as memory. Needed when the kernel wants to execute
 404  * code in external memory. This is needed for reprogramming source
 405  * clocks that would affect normal memory for example. Please see
 406  * CONFIG_GENERIC_ALLOCATOR for allocating external memory.
 407  */
 408 void __iomem *
 409 __arm_ioremap_exec(phys_addr_t phys_addr, size_t size, bool cached)
 410 {
 411         unsigned int mtype;
 412
 413         if (cached)
 414                 mtype = MT_MEMORY_RWX;
 415         else
 416                 mtype = MT_MEMORY_RWX_NONCACHED;
 417
 418         return __arm_ioremap_caller(phys_addr, size, mtype,
 419                         __builtin_return_address(0));
 420 }
 421
 422 void *arch_memremap_wb(phys_addr_t phys_addr, size_t size)
 423 {
 424         return (__force void *)arch_ioremap_caller(phys_addr, size,
 425                                                    MT_MEMORY_RW,
 426                                                    __builtin_return_address(0));
 427 }
 428
 429 void __iounmap(volatile void __iomem *io_addr)
 430 {
 431         void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
 432         struct static_vm *svm;
 433
 434         /* If this is a static mapping, we must leave it alone */
 435         svm = find_static_vm_vaddr(addr);
 436         if (svm)
 437                 return;
 438
 439 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
 440         {
 441                 struct vm_struct *vm;
 442
 443                 vm = find_vm_area(addr);
 444
 445                 /*
 446                  * If this is a section based mapping we need to handle it
 447                  * specially as the VM subsystem does not know how to handle
 448                  * such a beast.
 449                  */
 450                 if (vm && (vm->flags & VM_ARM_SECTION_MAPPING))
 451                         unmap_area_sections((unsigned long)vm->addr, vm->size);
 452         }
 453 #endif
 454
 455         vunmap(addr);
 456 }
 457
 458 void (*arch_iounmap)(volatile void __iomem *) = __iounmap;
 459
 460 void iounmap(volatile void __iomem *cookie)
 461 {
 462         arch_iounmap(cookie);
 463 }
 464 EXPORT_SYMBOL(iounmap);
 465
 466 #ifdef CONFIG_PCI
 467 static int pci_ioremap_mem_type = MT_DEVICE;
 468
 469 void pci_ioremap_set_mem_type(int mem_type)
 470 {
 471         pci_ioremap_mem_type = mem_type;
 472 }
 473
 474 int pci_ioremap_io(unsigned int offset, phys_addr_t phys_addr)
 475 {
 476         BUG_ON(offset + SZ_64K > IO_SPACE_LIMIT);
 477
 478         return ioremap_page_range(PCI_IO_VIRT_BASE + offset,
 479                                   PCI_IO_VIRT_BASE + offset + SZ_64K,
 480                                   phys_addr,
 481                                   __pgprot(get_mem_type(pci_ioremap_mem_type)->prot_pte));
 482 }
 483 EXPORT_SYMBOL_GPL(pci_ioremap_io);
 484 #endif
 485
 486 /*
 487  * Must be called after early_fixmap_init
 488  */
 489 void __init early_ioremap_init(void)
 490 {
 491         early_ioremap_setup();
 492 }