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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 | ||
1da177e4 LT |
25 | #include <linux/sched.h> |
26 | #include <linux/kernel.h> | |
27 | #include <linux/errno.h> | |
28 | #include <linux/string.h> | |
29 | #include <linux/types.h> | |
1da177e4 LT |
30 | #include <linux/highmem.h> |
31 | #include <linux/dma-mapping.h> | |
1da177e4 LT |
32 | |
33 | #include <asm/tlbflush.h> | |
34 | ||
8b31e49d BH |
35 | #include "mmu_decl.h" |
36 | ||
84532a0f BH |
37 | /* |
38 | * This address range defaults to a value that is safe for all | |
39 | * platforms which currently set CONFIG_NOT_COHERENT_CACHE. It | |
40 | * can be further configured for specific applications under | |
41 | * the "Advanced Setup" menu. -Matt | |
42 | */ | |
8b31e49d BH |
43 | #define CONSISTENT_BASE (IOREMAP_TOP) |
44 | #define CONSISTENT_END (CONSISTENT_BASE + CONFIG_CONSISTENT_SIZE) | |
84532a0f BH |
45 | #define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT) |
46 | ||
47 | /* | |
48 | * This is the page table (2MB) covering uncached, DMA consistent allocations | |
49 | */ | |
84532a0f BH |
50 | static DEFINE_SPINLOCK(consistent_lock); |
51 | ||
52 | /* | |
53 | * VM region handling support. | |
54 | * | |
55 | * This should become something generic, handling VM region allocations for | |
56 | * vmalloc and similar (ioremap, module space, etc). | |
57 | * | |
58 | * I envisage vmalloc()'s supporting vm_struct becoming: | |
59 | * | |
60 | * struct vm_struct { | |
61 | * struct vm_region region; | |
62 | * unsigned long flags; | |
63 | * struct page **pages; | |
64 | * unsigned int nr_pages; | |
65 | * unsigned long phys_addr; | |
66 | * }; | |
67 | * | |
68 | * get_vm_area() would then call vm_region_alloc with an appropriate | |
69 | * struct vm_region head (eg): | |
70 | * | |
71 | * struct vm_region vmalloc_head = { | |
72 | * .vm_list = LIST_HEAD_INIT(vmalloc_head.vm_list), | |
73 | * .vm_start = VMALLOC_START, | |
74 | * .vm_end = VMALLOC_END, | |
75 | * }; | |
76 | * | |
77 | * However, vmalloc_head.vm_start is variable (typically, it is dependent on | |
78 | * the amount of RAM found at boot time.) I would imagine that get_vm_area() | |
79 | * would have to initialise this each time prior to calling vm_region_alloc(). | |
80 | */ | |
81 | struct ppc_vm_region { | |
82 | struct list_head vm_list; | |
83 | unsigned long vm_start; | |
84 | unsigned long vm_end; | |
85 | }; | |
86 | ||
87 | static struct ppc_vm_region consistent_head = { | |
88 | .vm_list = LIST_HEAD_INIT(consistent_head.vm_list), | |
89 | .vm_start = CONSISTENT_BASE, | |
90 | .vm_end = CONSISTENT_END, | |
91 | }; | |
92 | ||
93 | static struct ppc_vm_region * | |
94 | ppc_vm_region_alloc(struct ppc_vm_region *head, size_t size, gfp_t gfp) | |
95 | { | |
96 | unsigned long addr = head->vm_start, end = head->vm_end - size; | |
97 | unsigned long flags; | |
98 | struct ppc_vm_region *c, *new; | |
99 | ||
100 | new = kmalloc(sizeof(struct ppc_vm_region), gfp); | |
101 | if (!new) | |
102 | goto out; | |
103 | ||
104 | spin_lock_irqsave(&consistent_lock, flags); | |
105 | ||
106 | list_for_each_entry(c, &head->vm_list, vm_list) { | |
107 | if ((addr + size) < addr) | |
108 | goto nospc; | |
109 | if ((addr + size) <= c->vm_start) | |
110 | goto found; | |
111 | addr = c->vm_end; | |
112 | if (addr > end) | |
113 | goto nospc; | |
114 | } | |
115 | ||
116 | found: | |
117 | /* | |
118 | * Insert this entry _before_ the one we found. | |
119 | */ | |
120 | list_add_tail(&new->vm_list, &c->vm_list); | |
121 | new->vm_start = addr; | |
122 | new->vm_end = addr + size; | |
123 | ||
124 | spin_unlock_irqrestore(&consistent_lock, flags); | |
125 | return new; | |
126 | ||
127 | nospc: | |
128 | spin_unlock_irqrestore(&consistent_lock, flags); | |
129 | kfree(new); | |
130 | out: | |
131 | return NULL; | |
132 | } | |
133 | ||
134 | static struct ppc_vm_region *ppc_vm_region_find(struct ppc_vm_region *head, unsigned long addr) | |
135 | { | |
136 | struct ppc_vm_region *c; | |
137 | ||
138 | list_for_each_entry(c, &head->vm_list, vm_list) { | |
139 | if (c->vm_start == addr) | |
140 | goto out; | |
141 | } | |
142 | c = NULL; | |
143 | out: | |
144 | return c; | |
145 | } | |
146 | ||
1da177e4 LT |
147 | /* |
148 | * Allocate DMA-coherent memory space and return both the kernel remapped | |
149 | * virtual and bus address for that space. | |
150 | */ | |
151 | void * | |
8b31e49d | 152 | __dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp) |
1da177e4 LT |
153 | { |
154 | struct page *page; | |
84532a0f | 155 | struct ppc_vm_region *c; |
1da177e4 | 156 | unsigned long order; |
8b31e49d | 157 | u64 mask = ISA_DMA_THRESHOLD, limit; |
1da177e4 | 158 | |
8b31e49d BH |
159 | if (dev) { |
160 | mask = dev->coherent_dma_mask; | |
161 | ||
162 | /* | |
163 | * Sanity check the DMA mask - it must be non-zero, and | |
164 | * must be able to be satisfied by a DMA allocation. | |
165 | */ | |
166 | if (mask == 0) { | |
167 | dev_warn(dev, "coherent DMA mask is unset\n"); | |
168 | goto no_page; | |
169 | } | |
170 | ||
171 | if ((~mask) & ISA_DMA_THRESHOLD) { | |
172 | dev_warn(dev, "coherent DMA mask %#llx is smaller " | |
173 | "than system GFP_DMA mask %#llx\n", | |
174 | mask, (unsigned long long)ISA_DMA_THRESHOLD); | |
175 | goto no_page; | |
176 | } | |
84532a0f BH |
177 | } |
178 | ||
8b31e49d | 179 | |
1da177e4 LT |
180 | size = PAGE_ALIGN(size); |
181 | limit = (mask + 1) & ~mask; | |
8b31e49d BH |
182 | if ((limit && size >= limit) || |
183 | size >= (CONSISTENT_END - CONSISTENT_BASE)) { | |
84532a0f BH |
184 | printk(KERN_WARNING "coherent allocation too big (requested %#x mask %#Lx)\n", |
185 | size, mask); | |
1da177e4 LT |
186 | return NULL; |
187 | } | |
188 | ||
189 | order = get_order(size); | |
190 | ||
8b31e49d | 191 | /* Might be useful if we ever have a real legacy DMA zone... */ |
1da177e4 LT |
192 | if (mask != 0xffffffff) |
193 | gfp |= GFP_DMA; | |
194 | ||
195 | page = alloc_pages(gfp, order); | |
196 | if (!page) | |
197 | goto no_page; | |
198 | ||
199 | /* | |
200 | * Invalidate any data that might be lurking in the | |
201 | * kernel direct-mapped region for device DMA. | |
202 | */ | |
203 | { | |
204 | unsigned long kaddr = (unsigned long)page_address(page); | |
205 | memset(page_address(page), 0, size); | |
206 | flush_dcache_range(kaddr, kaddr + size); | |
207 | } | |
208 | ||
209 | /* | |
84532a0f | 210 | * Allocate a virtual address in the consistent mapping region. |
1da177e4 | 211 | */ |
84532a0f BH |
212 | c = ppc_vm_region_alloc(&consistent_head, size, |
213 | gfp & ~(__GFP_DMA | __GFP_HIGHMEM)); | |
214 | if (c) { | |
215 | unsigned long vaddr = c->vm_start; | |
84532a0f | 216 | struct page *end = page + (1 << order); |
1da177e4 | 217 | |
84532a0f BH |
218 | split_page(page, order); |
219 | ||
220 | /* | |
221 | * Set the "dma handle" | |
222 | */ | |
223 | *handle = page_to_phys(page); | |
1da177e4 | 224 | |
84532a0f | 225 | do { |
84532a0f | 226 | SetPageReserved(page); |
8b31e49d BH |
227 | map_page(vaddr, page_to_phys(page), |
228 | pgprot_noncached(PAGE_KERNEL)); | |
84532a0f | 229 | page++; |
84532a0f BH |
230 | vaddr += PAGE_SIZE; |
231 | } while (size -= PAGE_SIZE); | |
1da177e4 | 232 | |
84532a0f BH |
233 | /* |
234 | * Free the otherwise unused pages. | |
235 | */ | |
236 | while (page < end) { | |
237 | __free_page(page); | |
238 | page++; | |
239 | } | |
240 | ||
241 | return (void *)c->vm_start; | |
1da177e4 LT |
242 | } |
243 | ||
244 | if (page) | |
245 | __free_pages(page, order); | |
84532a0f | 246 | no_page: |
1da177e4 LT |
247 | return NULL; |
248 | } | |
249 | EXPORT_SYMBOL(__dma_alloc_coherent); | |
250 | ||
251 | /* | |
252 | * free a page as defined by the above mapping. | |
253 | */ | |
254 | void __dma_free_coherent(size_t size, void *vaddr) | |
255 | { | |
84532a0f BH |
256 | struct ppc_vm_region *c; |
257 | unsigned long flags, addr; | |
8b31e49d | 258 | |
84532a0f BH |
259 | size = PAGE_ALIGN(size); |
260 | ||
261 | spin_lock_irqsave(&consistent_lock, flags); | |
262 | ||
263 | c = ppc_vm_region_find(&consistent_head, (unsigned long)vaddr); | |
264 | if (!c) | |
265 | goto no_area; | |
266 | ||
267 | if ((c->vm_end - c->vm_start) != size) { | |
268 | printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n", | |
269 | __func__, c->vm_end - c->vm_start, size); | |
270 | dump_stack(); | |
271 | size = c->vm_end - c->vm_start; | |
272 | } | |
273 | ||
84532a0f BH |
274 | addr = c->vm_start; |
275 | do { | |
8b31e49d | 276 | pte_t *ptep; |
84532a0f BH |
277 | unsigned long pfn; |
278 | ||
8b31e49d BH |
279 | ptep = pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(addr), |
280 | addr), | |
281 | addr), | |
282 | addr); | |
283 | if (!pte_none(*ptep) && pte_present(*ptep)) { | |
284 | pfn = pte_pfn(*ptep); | |
285 | pte_clear(&init_mm, addr, ptep); | |
84532a0f BH |
286 | if (pfn_valid(pfn)) { |
287 | struct page *page = pfn_to_page(pfn); | |
84532a0f | 288 | |
8b31e49d | 289 | ClearPageReserved(page); |
84532a0f | 290 | __free_page(page); |
84532a0f BH |
291 | } |
292 | } | |
8b31e49d | 293 | addr += PAGE_SIZE; |
84532a0f BH |
294 | } while (size -= PAGE_SIZE); |
295 | ||
296 | flush_tlb_kernel_range(c->vm_start, c->vm_end); | |
297 | ||
298 | list_del(&c->vm_list); | |
299 | ||
300 | spin_unlock_irqrestore(&consistent_lock, flags); | |
301 | ||
302 | kfree(c); | |
303 | return; | |
304 | ||
305 | no_area: | |
306 | spin_unlock_irqrestore(&consistent_lock, flags); | |
307 | printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n", | |
308 | __func__, vaddr); | |
309 | dump_stack(); | |
1da177e4 LT |
310 | } |
311 | EXPORT_SYMBOL(__dma_free_coherent); | |
312 | ||
1da177e4 LT |
313 | /* |
314 | * make an area consistent. | |
315 | */ | |
316 | void __dma_sync(void *vaddr, size_t size, int direction) | |
317 | { | |
318 | unsigned long start = (unsigned long)vaddr; | |
319 | unsigned long end = start + size; | |
320 | ||
321 | switch (direction) { | |
322 | case DMA_NONE: | |
323 | BUG(); | |
03d70617 AL |
324 | case DMA_FROM_DEVICE: |
325 | /* | |
326 | * invalidate only when cache-line aligned otherwise there is | |
327 | * the potential for discarding uncommitted data from the cache | |
328 | */ | |
329 | if ((start & (L1_CACHE_BYTES - 1)) || (size & (L1_CACHE_BYTES - 1))) | |
330 | flush_dcache_range(start, end); | |
331 | else | |
332 | invalidate_dcache_range(start, end); | |
1da177e4 LT |
333 | break; |
334 | case DMA_TO_DEVICE: /* writeback only */ | |
335 | clean_dcache_range(start, end); | |
336 | break; | |
337 | case DMA_BIDIRECTIONAL: /* writeback and invalidate */ | |
338 | flush_dcache_range(start, end); | |
339 | break; | |
340 | } | |
341 | } | |
342 | EXPORT_SYMBOL(__dma_sync); | |
343 | ||
344 | #ifdef CONFIG_HIGHMEM | |
345 | /* | |
346 | * __dma_sync_page() implementation for systems using highmem. | |
347 | * In this case, each page of a buffer must be kmapped/kunmapped | |
348 | * in order to have a virtual address for __dma_sync(). This must | |
338cec32 | 349 | * not sleep so kmap_atomic()/kunmap_atomic() are used. |
1da177e4 LT |
350 | * |
351 | * Note: yes, it is possible and correct to have a buffer extend | |
352 | * beyond the first page. | |
353 | */ | |
354 | static inline void __dma_sync_page_highmem(struct page *page, | |
355 | unsigned long offset, size_t size, int direction) | |
356 | { | |
a0c111c6 | 357 | size_t seg_size = min((size_t)(PAGE_SIZE - offset), size); |
1da177e4 LT |
358 | size_t cur_size = seg_size; |
359 | unsigned long flags, start, seg_offset = offset; | |
a0c111c6 | 360 | int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/PAGE_SIZE; |
1da177e4 LT |
361 | int seg_nr = 0; |
362 | ||
363 | local_irq_save(flags); | |
364 | ||
365 | do { | |
366 | start = (unsigned long)kmap_atomic(page + seg_nr, | |
367 | KM_PPC_SYNC_PAGE) + seg_offset; | |
368 | ||
369 | /* Sync this buffer segment */ | |
370 | __dma_sync((void *)start, seg_size, direction); | |
371 | kunmap_atomic((void *)start, KM_PPC_SYNC_PAGE); | |
372 | seg_nr++; | |
373 | ||
374 | /* Calculate next buffer segment size */ | |
375 | seg_size = min((size_t)PAGE_SIZE, size - cur_size); | |
376 | ||
377 | /* Add the segment size to our running total */ | |
378 | cur_size += seg_size; | |
379 | seg_offset = 0; | |
380 | } while (seg_nr < nr_segs); | |
381 | ||
382 | local_irq_restore(flags); | |
383 | } | |
384 | #endif /* CONFIG_HIGHMEM */ | |
385 | ||
386 | /* | |
387 | * __dma_sync_page makes memory consistent. identical to __dma_sync, but | |
388 | * takes a struct page instead of a virtual address | |
389 | */ | |
390 | void __dma_sync_page(struct page *page, unsigned long offset, | |
391 | size_t size, int direction) | |
392 | { | |
393 | #ifdef CONFIG_HIGHMEM | |
394 | __dma_sync_page_highmem(page, offset, size, direction); | |
395 | #else | |
396 | unsigned long start = (unsigned long)page_address(page) + offset; | |
397 | __dma_sync((void *)start, size, direction); | |
398 | #endif | |
399 | } | |
400 | EXPORT_SYMBOL(__dma_sync_page); |