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 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         area->phys_addr = __pfn_to_phys(pfn);
 252
 253 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
 254         if (DOMAIN_IO == 0 &&
 255             (((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) ||
 256                cpu_is_xsc3()) && pfn >= 0x100000 &&
 257                !((__pfn_to_phys(pfn) | size | addr) & ~SUPERSECTION_MASK)) {
 258                 area->flags |= VM_ARM_SECTION_MAPPING;
 259                 err = remap_area_supersections(addr, pfn, size, type);
 260         } else if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) {
 261                 area->flags |= VM_ARM_SECTION_MAPPING;
 262                 err = remap_area_sections(addr, pfn, size, type);
 263         } else
 264 #endif
 265                 err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn),
 266                                          __pgprot(type->prot_pte));
 267
 268         if (err) {
 269                 vunmap((void *)addr);
 270                 return NULL;
 271         }
 272
 273         flush_cache_vmap(addr, addr + size);
 274         return (void __iomem *) (offset + addr);
 275 }
 276
 277 void __iomem *__arm_ioremap_caller(unsigned long phys_addr, size_t size,
 278         unsigned int mtype, void *caller)
 279 {
 280         unsigned long last_addr;
 281         unsigned long offset = phys_addr & ~PAGE_MASK;
 282         unsigned long pfn = __phys_to_pfn(phys_addr);
 283
 284         /*
 285          * Don't allow wraparound or zero size
 286          */
 287         last_addr = phys_addr + size - 1;
 288         if (!size || last_addr < phys_addr)
 289                 return NULL;
 290
 291         return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
 292                         caller);
 293 }
 294
 295 /*
 296  * Remap an arbitrary physical address space into the kernel virtual
 297  * address space. Needed when the kernel wants to access high addresses
 298  * directly.
 299  *
 300  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 301  * have to convert them into an offset in a page-aligned mapping, but the
 302  * caller shouldn't need to know that small detail.
 303  */
 304 void __iomem *
 305 __arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
 306                   unsigned int mtype)
 307 {
 308         return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
 309                         __builtin_return_address(0));
 310 }
 311 EXPORT_SYMBOL(__arm_ioremap_pfn);
 312
 313 void __iomem * (*arch_ioremap_caller)(unsigned long, size_t,
 314                                       unsigned int, void *) =
 315         __arm_ioremap_caller;
 316
 317 void __iomem *
 318 __arm_ioremap(unsigned long phys_addr, size_t size, unsigned int mtype)
 319 {
 320         return arch_ioremap_caller(phys_addr, size, mtype,
 321                 __builtin_return_address(0));
 322 }
 323 EXPORT_SYMBOL(__arm_ioremap);
 324
 325 /*
 326  * Remap an arbitrary physical address space into the kernel virtual
 327  * address space as memory. Needed when the kernel wants to execute
 328  * code in external memory. This is needed for reprogramming source
 329  * clocks that would affect normal memory for example. Please see
 330  * CONFIG_GENERIC_ALLOCATOR for allocating external memory.
 331  */
 332 void __iomem *
 333 __arm_ioremap_exec(unsigned long phys_addr, size_t size, bool cached)
 334 {
 335         unsigned int mtype;
 336
 337         if (cached)
 338                 mtype = MT_MEMORY;
 339         else
 340                 mtype = MT_MEMORY_NONCACHED;
 341
 342         return __arm_ioremap_caller(phys_addr, size, mtype,
 343                         __builtin_return_address(0));
 344 }
 345
 346 void __iounmap(volatile void __iomem *io_addr)
 347 {
 348         void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
 349         struct vm_struct *vm;
 350
 351         read_lock(&vmlist_lock);
 352         for (vm = vmlist; vm; vm = vm->next) {
 353                 if (vm->addr > addr)
 354                         break;
 355                 if (!(vm->flags & VM_IOREMAP))
 356                         continue;
 357                 /* If this is a static mapping we must leave it alone */
 358                 if ((vm->flags & VM_ARM_STATIC_MAPPING) &&
 359                     (vm->addr <= addr) && (vm->addr + vm->size > addr)) {
 360                         read_unlock(&vmlist_lock);
 361                         return;
 362                 }
 363 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
 364                 /*
 365                  * If this is a section based mapping we need to handle it
 366                  * specially as the VM subsystem does not know how to handle
 367                  * such a beast.
 368                  */
 369                 if ((vm->addr == addr) &&
 370                     (vm->flags & VM_ARM_SECTION_MAPPING)) {
 371                         unmap_area_sections((unsigned long)vm->addr, vm->size);
 372                         break;
 373                 }
 374 #endif
 375         }
 376         read_unlock(&vmlist_lock);
 377
 378         vunmap(addr);
 379 }
 380
 381 void (*arch_iounmap)(volatile void __iomem *) = __iounmap;
 382
 383 void __arm_iounmap(volatile void __iomem *io_addr)
 384 {
 385         arch_iounmap(io_addr);
 386 }
 387 EXPORT_SYMBOL(__arm_iounmap);
 388
 389 #ifdef CONFIG_PCI
 390 int pci_ioremap_io(unsigned int offset, phys_addr_t phys_addr)
 391 {
 392         BUG_ON(offset + SZ_64K > IO_SPACE_LIMIT);
 393
 394         return ioremap_page_range(PCI_IO_VIRT_BASE + offset,
 395                                   PCI_IO_VIRT_BASE + offset + SZ_64K,
 396                                   phys_addr,
 397                                   __pgprot(get_mem_type(MT_DEVICE)->prot_pte));
 398 }
 399 EXPORT_SYMBOL_GPL(pci_ioremap_io);
 400 #endif