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1da177e4 LT |
1 | /* |
2 | * PowerPC version derived from arch/arm/mm/consistent.c | |
3 | * Copyright (C) 2001 Dan Malek (dmalek@jlc.net) | |
4 | * | |
5 | * Copyright (C) 2000 Russell King | |
6 | * | |
7 | * Consistent memory allocators. Used for DMA devices that want to | |
8 | * share uncached memory with the processor core. The function return | |
9 | * is the virtual address and 'dma_handle' is the physical address. | |
10 | * Mostly stolen from the ARM port, with some changes for PowerPC. | |
11 | * -- Dan | |
12 | * | |
13 | * Reorganized to get rid of the arch-specific consistent_* functions | |
14 | * and provide non-coherent implementations for the DMA API. -Matt | |
15 | * | |
16 | * Added in_interrupt() safe dma_alloc_coherent()/dma_free_coherent() | |
17 | * implementation. This is pulled straight from ARM and barely | |
18 | * modified. -Matt | |
19 | * | |
20 | * This program is free software; you can redistribute it and/or modify | |
21 | * it under the terms of the GNU General Public License version 2 as | |
22 | * published by the Free Software Foundation. | |
23 | */ | |
24 | ||
25 | #include <linux/config.h> | |
26 | #include <linux/module.h> | |
27 | #include <linux/signal.h> | |
28 | #include <linux/sched.h> | |
29 | #include <linux/kernel.h> | |
30 | #include <linux/errno.h> | |
31 | #include <linux/string.h> | |
32 | #include <linux/types.h> | |
33 | #include <linux/ptrace.h> | |
34 | #include <linux/mman.h> | |
35 | #include <linux/mm.h> | |
36 | #include <linux/swap.h> | |
37 | #include <linux/stddef.h> | |
38 | #include <linux/vmalloc.h> | |
39 | #include <linux/init.h> | |
40 | #include <linux/delay.h> | |
41 | #include <linux/bootmem.h> | |
42 | #include <linux/highmem.h> | |
43 | #include <linux/dma-mapping.h> | |
44 | #include <linux/hardirq.h> | |
45 | ||
46 | #include <asm/pgalloc.h> | |
47 | #include <asm/prom.h> | |
48 | #include <asm/io.h> | |
49 | #include <asm/mmu_context.h> | |
50 | #include <asm/pgtable.h> | |
51 | #include <asm/mmu.h> | |
52 | #include <asm/uaccess.h> | |
53 | #include <asm/smp.h> | |
54 | #include <asm/machdep.h> | |
55 | ||
56 | int map_page(unsigned long va, phys_addr_t pa, int flags); | |
57 | ||
58 | #include <asm/tlbflush.h> | |
59 | ||
60 | /* | |
61 | * This address range defaults to a value that is safe for all | |
62 | * platforms which currently set CONFIG_NOT_COHERENT_CACHE. It | |
63 | * can be further configured for specific applications under | |
64 | * the "Advanced Setup" menu. -Matt | |
65 | */ | |
66 | #define CONSISTENT_BASE (CONFIG_CONSISTENT_START) | |
67 | #define CONSISTENT_END (CONFIG_CONSISTENT_START + CONFIG_CONSISTENT_SIZE) | |
68 | #define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT) | |
69 | ||
70 | /* | |
71 | * This is the page table (2MB) covering uncached, DMA consistent allocations | |
72 | */ | |
73 | static pte_t *consistent_pte; | |
74 | static DEFINE_SPINLOCK(consistent_lock); | |
75 | ||
76 | /* | |
77 | * VM region handling support. | |
78 | * | |
79 | * This should become something generic, handling VM region allocations for | |
80 | * vmalloc and similar (ioremap, module space, etc). | |
81 | * | |
82 | * I envisage vmalloc()'s supporting vm_struct becoming: | |
83 | * | |
84 | * struct vm_struct { | |
85 | * struct vm_region region; | |
86 | * unsigned long flags; | |
87 | * struct page **pages; | |
88 | * unsigned int nr_pages; | |
89 | * unsigned long phys_addr; | |
90 | * }; | |
91 | * | |
92 | * get_vm_area() would then call vm_region_alloc with an appropriate | |
93 | * struct vm_region head (eg): | |
94 | * | |
95 | * struct vm_region vmalloc_head = { | |
96 | * .vm_list = LIST_HEAD_INIT(vmalloc_head.vm_list), | |
97 | * .vm_start = VMALLOC_START, | |
98 | * .vm_end = VMALLOC_END, | |
99 | * }; | |
100 | * | |
101 | * However, vmalloc_head.vm_start is variable (typically, it is dependent on | |
102 | * the amount of RAM found at boot time.) I would imagine that get_vm_area() | |
103 | * would have to initialise this each time prior to calling vm_region_alloc(). | |
104 | */ | |
105 | struct vm_region { | |
106 | struct list_head vm_list; | |
107 | unsigned long vm_start; | |
108 | unsigned long vm_end; | |
109 | }; | |
110 | ||
111 | static struct vm_region consistent_head = { | |
112 | .vm_list = LIST_HEAD_INIT(consistent_head.vm_list), | |
113 | .vm_start = CONSISTENT_BASE, | |
114 | .vm_end = CONSISTENT_END, | |
115 | }; | |
116 | ||
117 | static struct vm_region * | |
118 | vm_region_alloc(struct vm_region *head, size_t size, int gfp) | |
119 | { | |
120 | unsigned long addr = head->vm_start, end = head->vm_end - size; | |
121 | unsigned long flags; | |
122 | struct vm_region *c, *new; | |
123 | ||
124 | new = kmalloc(sizeof(struct vm_region), gfp); | |
125 | if (!new) | |
126 | goto out; | |
127 | ||
128 | spin_lock_irqsave(&consistent_lock, flags); | |
129 | ||
130 | list_for_each_entry(c, &head->vm_list, vm_list) { | |
131 | if ((addr + size) < addr) | |
132 | goto nospc; | |
133 | if ((addr + size) <= c->vm_start) | |
134 | goto found; | |
135 | addr = c->vm_end; | |
136 | if (addr > end) | |
137 | goto nospc; | |
138 | } | |
139 | ||
140 | found: | |
141 | /* | |
142 | * Insert this entry _before_ the one we found. | |
143 | */ | |
144 | list_add_tail(&new->vm_list, &c->vm_list); | |
145 | new->vm_start = addr; | |
146 | new->vm_end = addr + size; | |
147 | ||
148 | spin_unlock_irqrestore(&consistent_lock, flags); | |
149 | return new; | |
150 | ||
151 | nospc: | |
152 | spin_unlock_irqrestore(&consistent_lock, flags); | |
153 | kfree(new); | |
154 | out: | |
155 | return NULL; | |
156 | } | |
157 | ||
158 | static struct vm_region *vm_region_find(struct vm_region *head, unsigned long addr) | |
159 | { | |
160 | struct vm_region *c; | |
161 | ||
162 | list_for_each_entry(c, &head->vm_list, vm_list) { | |
163 | if (c->vm_start == addr) | |
164 | goto out; | |
165 | } | |
166 | c = NULL; | |
167 | out: | |
168 | return c; | |
169 | } | |
170 | ||
171 | /* | |
172 | * Allocate DMA-coherent memory space and return both the kernel remapped | |
173 | * virtual and bus address for that space. | |
174 | */ | |
175 | void * | |
176 | __dma_alloc_coherent(size_t size, dma_addr_t *handle, int gfp) | |
177 | { | |
178 | struct page *page; | |
179 | struct vm_region *c; | |
180 | unsigned long order; | |
181 | u64 mask = 0x00ffffff, limit; /* ISA default */ | |
182 | ||
183 | if (!consistent_pte) { | |
184 | printk(KERN_ERR "%s: not initialised\n", __func__); | |
185 | dump_stack(); | |
186 | return NULL; | |
187 | } | |
188 | ||
189 | size = PAGE_ALIGN(size); | |
190 | limit = (mask + 1) & ~mask; | |
191 | if ((limit && size >= limit) || size >= (CONSISTENT_END - CONSISTENT_BASE)) { | |
192 | printk(KERN_WARNING "coherent allocation too big (requested %#x mask %#Lx)\n", | |
193 | size, mask); | |
194 | return NULL; | |
195 | } | |
196 | ||
197 | order = get_order(size); | |
198 | ||
199 | if (mask != 0xffffffff) | |
200 | gfp |= GFP_DMA; | |
201 | ||
202 | page = alloc_pages(gfp, order); | |
203 | if (!page) | |
204 | goto no_page; | |
205 | ||
206 | /* | |
207 | * Invalidate any data that might be lurking in the | |
208 | * kernel direct-mapped region for device DMA. | |
209 | */ | |
210 | { | |
211 | unsigned long kaddr = (unsigned long)page_address(page); | |
212 | memset(page_address(page), 0, size); | |
213 | flush_dcache_range(kaddr, kaddr + size); | |
214 | } | |
215 | ||
216 | /* | |
217 | * Allocate a virtual address in the consistent mapping region. | |
218 | */ | |
219 | c = vm_region_alloc(&consistent_head, size, | |
220 | gfp & ~(__GFP_DMA | __GFP_HIGHMEM)); | |
221 | if (c) { | |
222 | unsigned long vaddr = c->vm_start; | |
223 | pte_t *pte = consistent_pte + CONSISTENT_OFFSET(vaddr); | |
224 | struct page *end = page + (1 << order); | |
225 | ||
226 | /* | |
227 | * Set the "dma handle" | |
228 | */ | |
229 | *handle = page_to_bus(page); | |
230 | ||
231 | do { | |
232 | BUG_ON(!pte_none(*pte)); | |
233 | ||
234 | set_page_count(page, 1); | |
235 | SetPageReserved(page); | |
236 | set_pte_at(&init_mm, vaddr, | |
237 | pte, mk_pte(page, pgprot_noncached(PAGE_KERNEL))); | |
238 | page++; | |
239 | pte++; | |
240 | vaddr += PAGE_SIZE; | |
241 | } while (size -= PAGE_SIZE); | |
242 | ||
243 | /* | |
244 | * Free the otherwise unused pages. | |
245 | */ | |
246 | while (page < end) { | |
247 | set_page_count(page, 1); | |
248 | __free_page(page); | |
249 | page++; | |
250 | } | |
251 | ||
252 | return (void *)c->vm_start; | |
253 | } | |
254 | ||
255 | if (page) | |
256 | __free_pages(page, order); | |
257 | no_page: | |
258 | return NULL; | |
259 | } | |
260 | EXPORT_SYMBOL(__dma_alloc_coherent); | |
261 | ||
262 | /* | |
263 | * free a page as defined by the above mapping. | |
264 | */ | |
265 | void __dma_free_coherent(size_t size, void *vaddr) | |
266 | { | |
267 | struct vm_region *c; | |
268 | unsigned long flags, addr; | |
269 | pte_t *ptep; | |
270 | ||
271 | size = PAGE_ALIGN(size); | |
272 | ||
273 | spin_lock_irqsave(&consistent_lock, flags); | |
274 | ||
275 | c = vm_region_find(&consistent_head, (unsigned long)vaddr); | |
276 | if (!c) | |
277 | goto no_area; | |
278 | ||
279 | if ((c->vm_end - c->vm_start) != size) { | |
280 | printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n", | |
281 | __func__, c->vm_end - c->vm_start, size); | |
282 | dump_stack(); | |
283 | size = c->vm_end - c->vm_start; | |
284 | } | |
285 | ||
286 | ptep = consistent_pte + CONSISTENT_OFFSET(c->vm_start); | |
287 | addr = c->vm_start; | |
288 | do { | |
289 | pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep); | |
290 | unsigned long pfn; | |
291 | ||
292 | ptep++; | |
293 | addr += PAGE_SIZE; | |
294 | ||
295 | if (!pte_none(pte) && pte_present(pte)) { | |
296 | pfn = pte_pfn(pte); | |
297 | ||
298 | if (pfn_valid(pfn)) { | |
299 | struct page *page = pfn_to_page(pfn); | |
300 | ClearPageReserved(page); | |
301 | ||
302 | __free_page(page); | |
303 | continue; | |
304 | } | |
305 | } | |
306 | ||
307 | printk(KERN_CRIT "%s: bad page in kernel page table\n", | |
308 | __func__); | |
309 | } while (size -= PAGE_SIZE); | |
310 | ||
311 | flush_tlb_kernel_range(c->vm_start, c->vm_end); | |
312 | ||
313 | list_del(&c->vm_list); | |
314 | ||
315 | spin_unlock_irqrestore(&consistent_lock, flags); | |
316 | ||
317 | kfree(c); | |
318 | return; | |
319 | ||
320 | no_area: | |
321 | spin_unlock_irqrestore(&consistent_lock, flags); | |
322 | printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n", | |
323 | __func__, vaddr); | |
324 | dump_stack(); | |
325 | } | |
326 | EXPORT_SYMBOL(__dma_free_coherent); | |
327 | ||
328 | /* | |
329 | * Initialise the consistent memory allocation. | |
330 | */ | |
331 | static int __init dma_alloc_init(void) | |
332 | { | |
333 | pgd_t *pgd; | |
334 | pmd_t *pmd; | |
335 | pte_t *pte; | |
336 | int ret = 0; | |
337 | ||
338 | spin_lock(&init_mm.page_table_lock); | |
339 | ||
340 | do { | |
341 | pgd = pgd_offset(&init_mm, CONSISTENT_BASE); | |
342 | pmd = pmd_alloc(&init_mm, pgd, CONSISTENT_BASE); | |
343 | if (!pmd) { | |
344 | printk(KERN_ERR "%s: no pmd tables\n", __func__); | |
345 | ret = -ENOMEM; | |
346 | break; | |
347 | } | |
348 | WARN_ON(!pmd_none(*pmd)); | |
349 | ||
350 | pte = pte_alloc_kernel(&init_mm, pmd, CONSISTENT_BASE); | |
351 | if (!pte) { | |
352 | printk(KERN_ERR "%s: no pte tables\n", __func__); | |
353 | ret = -ENOMEM; | |
354 | break; | |
355 | } | |
356 | ||
357 | consistent_pte = pte; | |
358 | } while (0); | |
359 | ||
360 | spin_unlock(&init_mm.page_table_lock); | |
361 | ||
362 | return ret; | |
363 | } | |
364 | ||
365 | core_initcall(dma_alloc_init); | |
366 | ||
367 | /* | |
368 | * make an area consistent. | |
369 | */ | |
370 | void __dma_sync(void *vaddr, size_t size, int direction) | |
371 | { | |
372 | unsigned long start = (unsigned long)vaddr; | |
373 | unsigned long end = start + size; | |
374 | ||
375 | switch (direction) { | |
376 | case DMA_NONE: | |
377 | BUG(); | |
378 | case DMA_FROM_DEVICE: /* invalidate only */ | |
379 | invalidate_dcache_range(start, end); | |
380 | break; | |
381 | case DMA_TO_DEVICE: /* writeback only */ | |
382 | clean_dcache_range(start, end); | |
383 | break; | |
384 | case DMA_BIDIRECTIONAL: /* writeback and invalidate */ | |
385 | flush_dcache_range(start, end); | |
386 | break; | |
387 | } | |
388 | } | |
389 | EXPORT_SYMBOL(__dma_sync); | |
390 | ||
391 | #ifdef CONFIG_HIGHMEM | |
392 | /* | |
393 | * __dma_sync_page() implementation for systems using highmem. | |
394 | * In this case, each page of a buffer must be kmapped/kunmapped | |
395 | * in order to have a virtual address for __dma_sync(). This must | |
338cec32 | 396 | * not sleep so kmap_atomic()/kunmap_atomic() are used. |
1da177e4 LT |
397 | * |
398 | * Note: yes, it is possible and correct to have a buffer extend | |
399 | * beyond the first page. | |
400 | */ | |
401 | static inline void __dma_sync_page_highmem(struct page *page, | |
402 | unsigned long offset, size_t size, int direction) | |
403 | { | |
404 | size_t seg_size = min((size_t)PAGE_SIZE, size) - offset; | |
405 | size_t cur_size = seg_size; | |
406 | unsigned long flags, start, seg_offset = offset; | |
407 | int nr_segs = PAGE_ALIGN(size + (PAGE_SIZE - offset))/PAGE_SIZE; | |
408 | int seg_nr = 0; | |
409 | ||
410 | local_irq_save(flags); | |
411 | ||
412 | do { | |
413 | start = (unsigned long)kmap_atomic(page + seg_nr, | |
414 | KM_PPC_SYNC_PAGE) + seg_offset; | |
415 | ||
416 | /* Sync this buffer segment */ | |
417 | __dma_sync((void *)start, seg_size, direction); | |
418 | kunmap_atomic((void *)start, KM_PPC_SYNC_PAGE); | |
419 | seg_nr++; | |
420 | ||
421 | /* Calculate next buffer segment size */ | |
422 | seg_size = min((size_t)PAGE_SIZE, size - cur_size); | |
423 | ||
424 | /* Add the segment size to our running total */ | |
425 | cur_size += seg_size; | |
426 | seg_offset = 0; | |
427 | } while (seg_nr < nr_segs); | |
428 | ||
429 | local_irq_restore(flags); | |
430 | } | |
431 | #endif /* CONFIG_HIGHMEM */ | |
432 | ||
433 | /* | |
434 | * __dma_sync_page makes memory consistent. identical to __dma_sync, but | |
435 | * takes a struct page instead of a virtual address | |
436 | */ | |
437 | void __dma_sync_page(struct page *page, unsigned long offset, | |
438 | size_t size, int direction) | |
439 | { | |
440 | #ifdef CONFIG_HIGHMEM | |
441 | __dma_sync_page_highmem(page, offset, size, direction); | |
442 | #else | |
443 | unsigned long start = (unsigned long)page_address(page) + offset; | |
444 | __dma_sync((void *)start, size, direction); | |
445 | #endif | |
446 | } | |
447 | EXPORT_SYMBOL(__dma_sync_page); |