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Linux/arch/arm/mm/ioremap.c

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  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 
485 void __iomem *pci_remap_cfgspace(resource_size_t res_cookie, size_t size)
486 {
487         return arch_ioremap_caller(res_cookie, size, MT_UNCACHED,
488                                    __builtin_return_address(0));
489 }
490 EXPORT_SYMBOL_GPL(pci_remap_cfgspace);
491 #endif
492 
493 /*
494  * Must be called after early_fixmap_init
495  */
496 void __init early_ioremap_init(void)
497 {
498         early_ioremap_setup();
499 }
500 

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