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/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;
 396         else
 397                 mtype = MT_MEMORY_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