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1da177e4 LT |
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 | ||
28 | #include <asm/cacheflush.h> | |
29 | #include <asm/io.h> | |
ff0daca5 RK |
30 | #include <asm/mmu_context.h> |
31 | #include <asm/pgalloc.h> | |
1da177e4 | 32 | #include <asm/tlbflush.h> |
ff0daca5 RK |
33 | #include <asm/sizes.h> |
34 | ||
35 | /* | |
a069c896 LB |
36 | * Used by ioremap() and iounmap() code to mark (super)section-mapped |
37 | * I/O regions in vm_struct->flags field. | |
ff0daca5 RK |
38 | */ |
39 | #define VM_ARM_SECTION_MAPPING 0x80000000 | |
1da177e4 LT |
40 | |
41 | static inline void | |
42 | remap_area_pte(pte_t * pte, unsigned long address, unsigned long size, | |
43 | unsigned long phys_addr, pgprot_t pgprot) | |
44 | { | |
45 | unsigned long end; | |
46 | ||
47 | address &= ~PMD_MASK; | |
48 | end = address + size; | |
49 | if (end > PMD_SIZE) | |
50 | end = PMD_SIZE; | |
51 | BUG_ON(address >= end); | |
52 | do { | |
53 | if (!pte_none(*pte)) | |
54 | goto bad; | |
55 | ||
56 | set_pte(pte, pfn_pte(phys_addr >> PAGE_SHIFT, pgprot)); | |
57 | address += PAGE_SIZE; | |
58 | phys_addr += PAGE_SIZE; | |
59 | pte++; | |
60 | } while (address && (address < end)); | |
61 | return; | |
62 | ||
63 | bad: | |
64 | printk("remap_area_pte: page already exists\n"); | |
65 | BUG(); | |
66 | } | |
67 | ||
68 | static inline int | |
69 | remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size, | |
70 | unsigned long phys_addr, unsigned long flags) | |
71 | { | |
72 | unsigned long end; | |
73 | pgprot_t pgprot; | |
74 | ||
75 | address &= ~PGDIR_MASK; | |
76 | end = address + size; | |
77 | ||
78 | if (end > PGDIR_SIZE) | |
79 | end = PGDIR_SIZE; | |
80 | ||
81 | phys_addr -= address; | |
82 | BUG_ON(address >= end); | |
83 | ||
84 | pgprot = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY | L_PTE_WRITE | flags); | |
85 | do { | |
872fec16 | 86 | pte_t * pte = pte_alloc_kernel(pmd, address); |
1da177e4 LT |
87 | if (!pte) |
88 | return -ENOMEM; | |
89 | remap_area_pte(pte, address, end - address, address + phys_addr, pgprot); | |
90 | address = (address + PMD_SIZE) & PMD_MASK; | |
91 | pmd++; | |
92 | } while (address && (address < end)); | |
93 | return 0; | |
94 | } | |
95 | ||
96 | static int | |
9d4ae727 | 97 | remap_area_pages(unsigned long start, unsigned long pfn, |
1da177e4 LT |
98 | unsigned long size, unsigned long flags) |
99 | { | |
100 | unsigned long address = start; | |
101 | unsigned long end = start + size; | |
9d4ae727 | 102 | unsigned long phys_addr = __pfn_to_phys(pfn); |
1da177e4 LT |
103 | int err = 0; |
104 | pgd_t * dir; | |
105 | ||
106 | phys_addr -= address; | |
107 | dir = pgd_offset(&init_mm, address); | |
108 | BUG_ON(address >= end); | |
1da177e4 LT |
109 | do { |
110 | pmd_t *pmd = pmd_alloc(&init_mm, dir, address); | |
111 | if (!pmd) { | |
112 | err = -ENOMEM; | |
113 | break; | |
114 | } | |
115 | if (remap_area_pmd(pmd, address, end - address, | |
116 | phys_addr + address, flags)) { | |
117 | err = -ENOMEM; | |
118 | break; | |
119 | } | |
120 | ||
121 | address = (address + PGDIR_SIZE) & PGDIR_MASK; | |
122 | dir++; | |
123 | } while (address && (address < end)); | |
124 | ||
1da177e4 LT |
125 | return err; |
126 | } | |
127 | ||
ff0daca5 RK |
128 | |
129 | void __check_kvm_seq(struct mm_struct *mm) | |
130 | { | |
131 | unsigned int seq; | |
132 | ||
133 | do { | |
134 | seq = init_mm.context.kvm_seq; | |
135 | memcpy(pgd_offset(mm, VMALLOC_START), | |
136 | pgd_offset_k(VMALLOC_START), | |
137 | sizeof(pgd_t) * (pgd_index(VMALLOC_END) - | |
138 | pgd_index(VMALLOC_START))); | |
139 | mm->context.kvm_seq = seq; | |
140 | } while (seq != init_mm.context.kvm_seq); | |
141 | } | |
142 | ||
143 | #ifndef CONFIG_SMP | |
144 | /* | |
145 | * Section support is unsafe on SMP - If you iounmap and ioremap a region, | |
146 | * the other CPUs will not see this change until their next context switch. | |
147 | * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs | |
148 | * which requires the new ioremap'd region to be referenced, the CPU will | |
149 | * reference the _old_ region. | |
150 | * | |
151 | * Note that get_vm_area() allocates a guard 4K page, so we need to mask | |
152 | * the size back to 1MB aligned or we will overflow in the loop below. | |
153 | */ | |
154 | static void unmap_area_sections(unsigned long virt, unsigned long size) | |
155 | { | |
156 | unsigned long addr = virt, end = virt + (size & ~SZ_1M); | |
157 | pgd_t *pgd; | |
158 | ||
159 | flush_cache_vunmap(addr, end); | |
160 | pgd = pgd_offset_k(addr); | |
161 | do { | |
162 | pmd_t pmd, *pmdp = pmd_offset(pgd, addr); | |
163 | ||
164 | pmd = *pmdp; | |
165 | if (!pmd_none(pmd)) { | |
166 | /* | |
167 | * Clear the PMD from the page table, and | |
168 | * increment the kvm sequence so others | |
169 | * notice this change. | |
170 | * | |
171 | * Note: this is still racy on SMP machines. | |
172 | */ | |
173 | pmd_clear(pmdp); | |
174 | init_mm.context.kvm_seq++; | |
175 | ||
176 | /* | |
177 | * Free the page table, if there was one. | |
178 | */ | |
179 | if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE) | |
46a82b2d | 180 | pte_free_kernel(pmd_page_vaddr(pmd)); |
ff0daca5 RK |
181 | } |
182 | ||
183 | addr += PGDIR_SIZE; | |
184 | pgd++; | |
185 | } while (addr < end); | |
186 | ||
187 | /* | |
188 | * Ensure that the active_mm is up to date - we want to | |
189 | * catch any use-after-iounmap cases. | |
190 | */ | |
191 | if (current->active_mm->context.kvm_seq != init_mm.context.kvm_seq) | |
192 | __check_kvm_seq(current->active_mm); | |
193 | ||
194 | flush_tlb_kernel_range(virt, end); | |
195 | } | |
196 | ||
197 | static int | |
198 | remap_area_sections(unsigned long virt, unsigned long pfn, | |
199 | unsigned long size, unsigned long flags) | |
200 | { | |
201 | unsigned long prot, addr = virt, end = virt + size; | |
202 | pgd_t *pgd; | |
203 | ||
204 | /* | |
205 | * Remove and free any PTE-based mapping, and | |
206 | * sync the current kernel mapping. | |
207 | */ | |
208 | unmap_area_sections(virt, size); | |
209 | ||
210 | prot = PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_DOMAIN(DOMAIN_IO) | | |
211 | (flags & (L_PTE_CACHEABLE | L_PTE_BUFFERABLE)); | |
212 | ||
213 | /* | |
214 | * ARMv6 and above need XN set to prevent speculative prefetches | |
215 | * hitting IO. | |
216 | */ | |
217 | if (cpu_architecture() >= CPU_ARCH_ARMv6) | |
218 | prot |= PMD_SECT_XN; | |
219 | ||
220 | pgd = pgd_offset_k(addr); | |
221 | do { | |
222 | pmd_t *pmd = pmd_offset(pgd, addr); | |
223 | ||
224 | pmd[0] = __pmd(__pfn_to_phys(pfn) | prot); | |
225 | pfn += SZ_1M >> PAGE_SHIFT; | |
226 | pmd[1] = __pmd(__pfn_to_phys(pfn) | prot); | |
227 | pfn += SZ_1M >> PAGE_SHIFT; | |
228 | flush_pmd_entry(pmd); | |
229 | ||
230 | addr += PGDIR_SIZE; | |
231 | pgd++; | |
232 | } while (addr < end); | |
233 | ||
234 | return 0; | |
235 | } | |
a069c896 LB |
236 | |
237 | static int | |
238 | remap_area_supersections(unsigned long virt, unsigned long pfn, | |
239 | unsigned long size, unsigned long flags) | |
240 | { | |
241 | unsigned long prot, addr = virt, end = virt + size; | |
242 | pgd_t *pgd; | |
243 | ||
244 | /* | |
245 | * Remove and free any PTE-based mapping, and | |
246 | * sync the current kernel mapping. | |
247 | */ | |
248 | unmap_area_sections(virt, size); | |
249 | ||
250 | prot = PMD_TYPE_SECT | PMD_SECT_SUPER | PMD_SECT_AP_WRITE | | |
251 | PMD_DOMAIN(DOMAIN_IO) | | |
252 | (flags & (L_PTE_CACHEABLE | L_PTE_BUFFERABLE)); | |
253 | ||
254 | /* | |
255 | * ARMv6 and above need XN set to prevent speculative prefetches | |
256 | * hitting IO. | |
257 | */ | |
258 | if (cpu_architecture() >= CPU_ARCH_ARMv6) | |
259 | prot |= PMD_SECT_XN; | |
260 | ||
261 | pgd = pgd_offset_k(virt); | |
262 | do { | |
263 | unsigned long super_pmd_val, i; | |
264 | ||
265 | super_pmd_val = __pfn_to_phys(pfn) | prot; | |
266 | super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20; | |
267 | ||
268 | for (i = 0; i < 8; i++) { | |
269 | pmd_t *pmd = pmd_offset(pgd, addr); | |
270 | ||
271 | pmd[0] = __pmd(super_pmd_val); | |
272 | pmd[1] = __pmd(super_pmd_val); | |
273 | flush_pmd_entry(pmd); | |
274 | ||
275 | addr += PGDIR_SIZE; | |
276 | pgd++; | |
277 | } | |
278 | ||
279 | pfn += SUPERSECTION_SIZE >> PAGE_SHIFT; | |
280 | } while (addr < end); | |
281 | ||
282 | return 0; | |
283 | } | |
ff0daca5 RK |
284 | #endif |
285 | ||
286 | ||
1da177e4 LT |
287 | /* |
288 | * Remap an arbitrary physical address space into the kernel virtual | |
289 | * address space. Needed when the kernel wants to access high addresses | |
290 | * directly. | |
291 | * | |
292 | * NOTE! We need to allow non-page-aligned mappings too: we will obviously | |
293 | * have to convert them into an offset in a page-aligned mapping, but the | |
294 | * caller shouldn't need to know that small detail. | |
295 | * | |
296 | * 'flags' are the extra L_PTE_ flags that you want to specify for this | |
297 | * mapping. See include/asm-arm/proc-armv/pgtable.h for more information. | |
298 | */ | |
9d4ae727 DS |
299 | void __iomem * |
300 | __ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size, | |
301 | unsigned long flags) | |
302 | { | |
ff0daca5 | 303 | int err; |
9d4ae727 DS |
304 | unsigned long addr; |
305 | struct vm_struct * area; | |
a069c896 LB |
306 | |
307 | /* | |
308 | * High mappings must be supersection aligned | |
309 | */ | |
310 | if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SUPERSECTION_MASK)) | |
311 | return NULL; | |
9d4ae727 DS |
312 | |
313 | area = get_vm_area(size, VM_IOREMAP); | |
314 | if (!area) | |
315 | return NULL; | |
316 | addr = (unsigned long)area->addr; | |
ff0daca5 RK |
317 | |
318 | #ifndef CONFIG_SMP | |
67f3a588 | 319 | if ((((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) || |
a069c896 LB |
320 | cpu_is_xsc3()) && |
321 | !((__pfn_to_phys(pfn) | size | addr) & ~SUPERSECTION_MASK)) { | |
322 | area->flags |= VM_ARM_SECTION_MAPPING; | |
323 | err = remap_area_supersections(addr, pfn, size, flags); | |
324 | } else if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) { | |
ff0daca5 RK |
325 | area->flags |= VM_ARM_SECTION_MAPPING; |
326 | err = remap_area_sections(addr, pfn, size, flags); | |
327 | } else | |
328 | #endif | |
329 | err = remap_area_pages(addr, pfn, size, flags); | |
330 | ||
331 | if (err) { | |
478922c2 | 332 | vunmap((void *)addr); |
9d4ae727 DS |
333 | return NULL; |
334 | } | |
ff0daca5 RK |
335 | |
336 | flush_cache_vmap(addr, addr + size); | |
337 | return (void __iomem *) (offset + addr); | |
9d4ae727 DS |
338 | } |
339 | EXPORT_SYMBOL(__ioremap_pfn); | |
340 | ||
1da177e4 | 341 | void __iomem * |
67a1901f | 342 | __ioremap(unsigned long phys_addr, size_t size, unsigned long flags) |
1da177e4 | 343 | { |
9d4ae727 DS |
344 | unsigned long last_addr; |
345 | unsigned long offset = phys_addr & ~PAGE_MASK; | |
346 | unsigned long pfn = __phys_to_pfn(phys_addr); | |
1da177e4 | 347 | |
9d4ae727 DS |
348 | /* |
349 | * Don't allow wraparound or zero size | |
350 | */ | |
1da177e4 LT |
351 | last_addr = phys_addr + size - 1; |
352 | if (!size || last_addr < phys_addr) | |
353 | return NULL; | |
354 | ||
355 | /* | |
9d4ae727 | 356 | * Page align the mapping size |
1da177e4 | 357 | */ |
1da177e4 LT |
358 | size = PAGE_ALIGN(last_addr + 1) - phys_addr; |
359 | ||
9d4ae727 | 360 | return __ioremap_pfn(pfn, offset, size, flags); |
1da177e4 LT |
361 | } |
362 | EXPORT_SYMBOL(__ioremap); | |
363 | ||
364 | void __iounmap(void __iomem *addr) | |
365 | { | |
ceaccbd2 | 366 | #ifndef CONFIG_SMP |
ff0daca5 | 367 | struct vm_struct **p, *tmp; |
ceaccbd2 | 368 | #endif |
ff0daca5 RK |
369 | unsigned int section_mapping = 0; |
370 | ||
371 | addr = (void __iomem *)(PAGE_MASK & (unsigned long)addr); | |
372 | ||
7cddc397 | 373 | #ifndef CONFIG_SMP |
ff0daca5 RK |
374 | /* |
375 | * If this is a section based mapping we need to handle it | |
376 | * specially as the VM subysystem does not know how to handle | |
377 | * such a beast. We need the lock here b/c we need to clear | |
378 | * all the mappings before the area can be reclaimed | |
379 | * by someone else. | |
380 | */ | |
381 | write_lock(&vmlist_lock); | |
382 | for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) { | |
383 | if((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) { | |
384 | if (tmp->flags & VM_ARM_SECTION_MAPPING) { | |
385 | *p = tmp->next; | |
386 | unmap_area_sections((unsigned long)tmp->addr, | |
387 | tmp->size); | |
388 | kfree(tmp); | |
389 | section_mapping = 1; | |
390 | } | |
391 | break; | |
392 | } | |
393 | } | |
394 | write_unlock(&vmlist_lock); | |
7cddc397 | 395 | #endif |
ff0daca5 RK |
396 | |
397 | if (!section_mapping) | |
398 | vunmap(addr); | |
1da177e4 LT |
399 | } |
400 | EXPORT_SYMBOL(__iounmap); |