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1da177e4 LT |
1 | /* |
2 | * linux/arch/arm/mm/consistent.c | |
3 | * | |
4 | * Copyright (C) 2000-2004 Russell King | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * DMA uncached mapping support. | |
11 | */ | |
12 | #include <linux/module.h> | |
13 | #include <linux/mm.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/errno.h> | |
16 | #include <linux/list.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/device.h> | |
19 | #include <linux/dma-mapping.h> | |
20 | ||
21 | #include <asm/cacheflush.h> | |
22 | #include <asm/io.h> | |
23 | #include <asm/tlbflush.h> | |
24 | ||
25 | #define CONSISTENT_BASE (0xffc00000) | |
26 | #define CONSISTENT_END (0xffe00000) | |
27 | #define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT) | |
28 | ||
29 | /* | |
30 | * This is the page table (2MB) covering uncached, DMA consistent allocations | |
31 | */ | |
32 | static pte_t *consistent_pte; | |
33 | static DEFINE_SPINLOCK(consistent_lock); | |
34 | ||
35 | /* | |
36 | * VM region handling support. | |
37 | * | |
38 | * This should become something generic, handling VM region allocations for | |
39 | * vmalloc and similar (ioremap, module space, etc). | |
40 | * | |
41 | * I envisage vmalloc()'s supporting vm_struct becoming: | |
42 | * | |
43 | * struct vm_struct { | |
44 | * struct vm_region region; | |
45 | * unsigned long flags; | |
46 | * struct page **pages; | |
47 | * unsigned int nr_pages; | |
48 | * unsigned long phys_addr; | |
49 | * }; | |
50 | * | |
51 | * get_vm_area() would then call vm_region_alloc with an appropriate | |
52 | * struct vm_region head (eg): | |
53 | * | |
54 | * struct vm_region vmalloc_head = { | |
55 | * .vm_list = LIST_HEAD_INIT(vmalloc_head.vm_list), | |
56 | * .vm_start = VMALLOC_START, | |
57 | * .vm_end = VMALLOC_END, | |
58 | * }; | |
59 | * | |
60 | * However, vmalloc_head.vm_start is variable (typically, it is dependent on | |
61 | * the amount of RAM found at boot time.) I would imagine that get_vm_area() | |
62 | * would have to initialise this each time prior to calling vm_region_alloc(). | |
63 | */ | |
64 | struct vm_region { | |
65 | struct list_head vm_list; | |
66 | unsigned long vm_start; | |
67 | unsigned long vm_end; | |
68 | struct page *vm_pages; | |
69 | }; | |
70 | ||
71 | static struct vm_region consistent_head = { | |
72 | .vm_list = LIST_HEAD_INIT(consistent_head.vm_list), | |
73 | .vm_start = CONSISTENT_BASE, | |
74 | .vm_end = CONSISTENT_END, | |
75 | }; | |
76 | ||
77 | static struct vm_region * | |
f9e3214a | 78 | vm_region_alloc(struct vm_region *head, size_t size, gfp_t gfp) |
1da177e4 LT |
79 | { |
80 | unsigned long addr = head->vm_start, end = head->vm_end - size; | |
81 | unsigned long flags; | |
82 | struct vm_region *c, *new; | |
83 | ||
84 | new = kmalloc(sizeof(struct vm_region), gfp); | |
85 | if (!new) | |
86 | goto out; | |
87 | ||
88 | spin_lock_irqsave(&consistent_lock, flags); | |
89 | ||
90 | list_for_each_entry(c, &head->vm_list, vm_list) { | |
91 | if ((addr + size) < addr) | |
92 | goto nospc; | |
93 | if ((addr + size) <= c->vm_start) | |
94 | goto found; | |
95 | addr = c->vm_end; | |
96 | if (addr > end) | |
97 | goto nospc; | |
98 | } | |
99 | ||
100 | found: | |
101 | /* | |
102 | * Insert this entry _before_ the one we found. | |
103 | */ | |
104 | list_add_tail(&new->vm_list, &c->vm_list); | |
105 | new->vm_start = addr; | |
106 | new->vm_end = addr + size; | |
107 | ||
108 | spin_unlock_irqrestore(&consistent_lock, flags); | |
109 | return new; | |
110 | ||
111 | nospc: | |
112 | spin_unlock_irqrestore(&consistent_lock, flags); | |
113 | kfree(new); | |
114 | out: | |
115 | return NULL; | |
116 | } | |
117 | ||
118 | static struct vm_region *vm_region_find(struct vm_region *head, unsigned long addr) | |
119 | { | |
120 | struct vm_region *c; | |
121 | ||
122 | list_for_each_entry(c, &head->vm_list, vm_list) { | |
123 | if (c->vm_start == addr) | |
124 | goto out; | |
125 | } | |
126 | c = NULL; | |
127 | out: | |
128 | return c; | |
129 | } | |
130 | ||
131 | #ifdef CONFIG_HUGETLB_PAGE | |
132 | #error ARM Coherent DMA allocator does not (yet) support huge TLB | |
133 | #endif | |
134 | ||
135 | static void * | |
f9e3214a | 136 | __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, |
1da177e4 LT |
137 | pgprot_t prot) |
138 | { | |
139 | struct page *page; | |
140 | struct vm_region *c; | |
141 | unsigned long order; | |
142 | u64 mask = ISA_DMA_THRESHOLD, limit; | |
143 | ||
144 | if (!consistent_pte) { | |
145 | printk(KERN_ERR "%s: not initialised\n", __func__); | |
146 | dump_stack(); | |
147 | return NULL; | |
148 | } | |
149 | ||
150 | if (dev) { | |
151 | mask = dev->coherent_dma_mask; | |
152 | ||
153 | /* | |
154 | * Sanity check the DMA mask - it must be non-zero, and | |
155 | * must be able to be satisfied by a DMA allocation. | |
156 | */ | |
157 | if (mask == 0) { | |
158 | dev_warn(dev, "coherent DMA mask is unset\n"); | |
159 | goto no_page; | |
160 | } | |
161 | ||
162 | if ((~mask) & ISA_DMA_THRESHOLD) { | |
163 | dev_warn(dev, "coherent DMA mask %#llx is smaller " | |
164 | "than system GFP_DMA mask %#llx\n", | |
165 | mask, (unsigned long long)ISA_DMA_THRESHOLD); | |
166 | goto no_page; | |
167 | } | |
168 | } | |
169 | ||
170 | /* | |
171 | * Sanity check the allocation size. | |
172 | */ | |
173 | size = PAGE_ALIGN(size); | |
174 | limit = (mask + 1) & ~mask; | |
175 | if ((limit && size >= limit) || | |
176 | size >= (CONSISTENT_END - CONSISTENT_BASE)) { | |
177 | printk(KERN_WARNING "coherent allocation too big " | |
178 | "(requested %#x mask %#llx)\n", size, mask); | |
179 | goto no_page; | |
180 | } | |
181 | ||
182 | order = get_order(size); | |
183 | ||
184 | if (mask != 0xffffffff) | |
185 | gfp |= GFP_DMA; | |
186 | ||
187 | page = alloc_pages(gfp, order); | |
188 | if (!page) | |
189 | goto no_page; | |
190 | ||
191 | /* | |
192 | * Invalidate any data that might be lurking in the | |
193 | * kernel direct-mapped region for device DMA. | |
194 | */ | |
195 | { | |
196 | unsigned long kaddr = (unsigned long)page_address(page); | |
197 | memset(page_address(page), 0, size); | |
198 | dmac_flush_range(kaddr, kaddr + size); | |
199 | } | |
200 | ||
201 | /* | |
202 | * Allocate a virtual address in the consistent mapping region. | |
203 | */ | |
204 | c = vm_region_alloc(&consistent_head, size, | |
205 | gfp & ~(__GFP_DMA | __GFP_HIGHMEM)); | |
206 | if (c) { | |
207 | pte_t *pte = consistent_pte + CONSISTENT_OFFSET(c->vm_start); | |
208 | struct page *end = page + (1 << order); | |
209 | ||
210 | c->vm_pages = page; | |
211 | ||
212 | /* | |
213 | * Set the "dma handle" | |
214 | */ | |
215 | *handle = page_to_dma(dev, page); | |
216 | ||
217 | do { | |
218 | BUG_ON(!pte_none(*pte)); | |
219 | ||
220 | set_page_count(page, 1); | |
221 | /* | |
222 | * x86 does not mark the pages reserved... | |
223 | */ | |
224 | SetPageReserved(page); | |
225 | set_pte(pte, mk_pte(page, prot)); | |
226 | page++; | |
227 | pte++; | |
228 | } while (size -= PAGE_SIZE); | |
229 | ||
230 | /* | |
231 | * Free the otherwise unused pages. | |
232 | */ | |
233 | while (page < end) { | |
234 | set_page_count(page, 1); | |
235 | __free_page(page); | |
236 | page++; | |
237 | } | |
238 | ||
239 | return (void *)c->vm_start; | |
240 | } | |
241 | ||
242 | if (page) | |
243 | __free_pages(page, order); | |
244 | no_page: | |
245 | *handle = ~0; | |
246 | return NULL; | |
247 | } | |
248 | ||
249 | /* | |
250 | * Allocate DMA-coherent memory space and return both the kernel remapped | |
251 | * virtual and bus address for that space. | |
252 | */ | |
253 | void * | |
f9e3214a | 254 | dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp) |
1da177e4 LT |
255 | { |
256 | return __dma_alloc(dev, size, handle, gfp, | |
257 | pgprot_noncached(pgprot_kernel)); | |
258 | } | |
259 | EXPORT_SYMBOL(dma_alloc_coherent); | |
260 | ||
261 | /* | |
262 | * Allocate a writecombining region, in much the same way as | |
263 | * dma_alloc_coherent above. | |
264 | */ | |
265 | void * | |
f9e3214a | 266 | dma_alloc_writecombine(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp) |
1da177e4 LT |
267 | { |
268 | return __dma_alloc(dev, size, handle, gfp, | |
269 | pgprot_writecombine(pgprot_kernel)); | |
270 | } | |
271 | EXPORT_SYMBOL(dma_alloc_writecombine); | |
272 | ||
273 | static int dma_mmap(struct device *dev, struct vm_area_struct *vma, | |
274 | void *cpu_addr, dma_addr_t dma_addr, size_t size) | |
275 | { | |
276 | unsigned long flags, user_size, kern_size; | |
277 | struct vm_region *c; | |
278 | int ret = -ENXIO; | |
279 | ||
280 | user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; | |
281 | ||
282 | spin_lock_irqsave(&consistent_lock, flags); | |
283 | c = vm_region_find(&consistent_head, (unsigned long)cpu_addr); | |
284 | spin_unlock_irqrestore(&consistent_lock, flags); | |
285 | ||
286 | if (c) { | |
287 | unsigned long off = vma->vm_pgoff; | |
288 | ||
289 | kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT; | |
290 | ||
291 | if (off < kern_size && | |
292 | user_size <= (kern_size - off)) { | |
293 | vma->vm_flags |= VM_RESERVED; | |
294 | ret = remap_pfn_range(vma, vma->vm_start, | |
295 | page_to_pfn(c->vm_pages) + off, | |
296 | user_size << PAGE_SHIFT, | |
297 | vma->vm_page_prot); | |
298 | } | |
299 | } | |
300 | ||
301 | return ret; | |
302 | } | |
303 | ||
304 | int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma, | |
305 | void *cpu_addr, dma_addr_t dma_addr, size_t size) | |
306 | { | |
307 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); | |
308 | return dma_mmap(dev, vma, cpu_addr, dma_addr, size); | |
309 | } | |
310 | EXPORT_SYMBOL(dma_mmap_coherent); | |
311 | ||
312 | int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma, | |
313 | void *cpu_addr, dma_addr_t dma_addr, size_t size) | |
314 | { | |
315 | vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); | |
316 | return dma_mmap(dev, vma, cpu_addr, dma_addr, size); | |
317 | } | |
318 | EXPORT_SYMBOL(dma_mmap_writecombine); | |
319 | ||
320 | /* | |
321 | * free a page as defined by the above mapping. | |
322 | */ | |
323 | void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle) | |
324 | { | |
325 | struct vm_region *c; | |
326 | unsigned long flags, addr; | |
327 | pte_t *ptep; | |
328 | ||
329 | size = PAGE_ALIGN(size); | |
330 | ||
331 | spin_lock_irqsave(&consistent_lock, flags); | |
332 | ||
333 | c = vm_region_find(&consistent_head, (unsigned long)cpu_addr); | |
334 | if (!c) | |
335 | goto no_area; | |
336 | ||
337 | if ((c->vm_end - c->vm_start) != size) { | |
338 | printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n", | |
339 | __func__, c->vm_end - c->vm_start, size); | |
340 | dump_stack(); | |
341 | size = c->vm_end - c->vm_start; | |
342 | } | |
343 | ||
344 | ptep = consistent_pte + CONSISTENT_OFFSET(c->vm_start); | |
345 | addr = c->vm_start; | |
346 | do { | |
347 | pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep); | |
348 | unsigned long pfn; | |
349 | ||
350 | ptep++; | |
351 | addr += PAGE_SIZE; | |
352 | ||
353 | if (!pte_none(pte) && pte_present(pte)) { | |
354 | pfn = pte_pfn(pte); | |
355 | ||
356 | if (pfn_valid(pfn)) { | |
357 | struct page *page = pfn_to_page(pfn); | |
358 | ||
359 | /* | |
360 | * x86 does not mark the pages reserved... | |
361 | */ | |
362 | ClearPageReserved(page); | |
363 | ||
364 | __free_page(page); | |
365 | continue; | |
366 | } | |
367 | } | |
368 | ||
369 | printk(KERN_CRIT "%s: bad page in kernel page table\n", | |
370 | __func__); | |
371 | } while (size -= PAGE_SIZE); | |
372 | ||
373 | flush_tlb_kernel_range(c->vm_start, c->vm_end); | |
374 | ||
375 | list_del(&c->vm_list); | |
376 | ||
377 | spin_unlock_irqrestore(&consistent_lock, flags); | |
378 | ||
379 | kfree(c); | |
380 | return; | |
381 | ||
382 | no_area: | |
383 | spin_unlock_irqrestore(&consistent_lock, flags); | |
384 | printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n", | |
385 | __func__, cpu_addr); | |
386 | dump_stack(); | |
387 | } | |
388 | EXPORT_SYMBOL(dma_free_coherent); | |
389 | ||
390 | /* | |
391 | * Initialise the consistent memory allocation. | |
392 | */ | |
393 | static int __init consistent_init(void) | |
394 | { | |
395 | pgd_t *pgd; | |
396 | pmd_t *pmd; | |
397 | pte_t *pte; | |
398 | int ret = 0; | |
399 | ||
400 | spin_lock(&init_mm.page_table_lock); | |
401 | ||
402 | do { | |
403 | pgd = pgd_offset(&init_mm, CONSISTENT_BASE); | |
404 | pmd = pmd_alloc(&init_mm, pgd, CONSISTENT_BASE); | |
405 | if (!pmd) { | |
406 | printk(KERN_ERR "%s: no pmd tables\n", __func__); | |
407 | ret = -ENOMEM; | |
408 | break; | |
409 | } | |
410 | WARN_ON(!pmd_none(*pmd)); | |
411 | ||
412 | pte = pte_alloc_kernel(&init_mm, pmd, CONSISTENT_BASE); | |
413 | if (!pte) { | |
414 | printk(KERN_ERR "%s: no pte tables\n", __func__); | |
415 | ret = -ENOMEM; | |
416 | break; | |
417 | } | |
418 | ||
419 | consistent_pte = pte; | |
420 | } while (0); | |
421 | ||
422 | spin_unlock(&init_mm.page_table_lock); | |
423 | ||
424 | return ret; | |
425 | } | |
426 | ||
427 | core_initcall(consistent_init); | |
428 | ||
429 | /* | |
430 | * Make an area consistent for devices. | |
431 | */ | |
432 | void consistent_sync(void *vaddr, size_t size, int direction) | |
433 | { | |
434 | unsigned long start = (unsigned long)vaddr; | |
435 | unsigned long end = start + size; | |
436 | ||
437 | switch (direction) { | |
438 | case DMA_FROM_DEVICE: /* invalidate only */ | |
439 | dmac_inv_range(start, end); | |
440 | break; | |
441 | case DMA_TO_DEVICE: /* writeback only */ | |
442 | dmac_clean_range(start, end); | |
443 | break; | |
444 | case DMA_BIDIRECTIONAL: /* writeback and invalidate */ | |
445 | dmac_flush_range(start, end); | |
446 | break; | |
447 | default: | |
448 | BUG(); | |
449 | } | |
450 | } | |
451 | EXPORT_SYMBOL(consistent_sync); |