xref: /openbmc/linux/drivers/gpu/drm/ttm/ttm_tt.c (revision 275876e2)
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4  * All Rights Reserved.
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11  * permit persons to whom the Software is furnished to do so, subject to
12  * the following conditions:
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14  * The above copyright notice and this permission notice (including the
15  * next paragraph) shall be included in all copies or substantial portions
16  * of the Software.
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19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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27 /*
28  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
29  */
30 
31 #define pr_fmt(fmt) "[TTM] " fmt
32 
33 #include <linux/sched.h>
34 #include <linux/highmem.h>
35 #include <linux/pagemap.h>
36 #include <linux/shmem_fs.h>
37 #include <linux/file.h>
38 #include <linux/swap.h>
39 #include <linux/slab.h>
40 #include <linux/export.h>
41 #include <drm/drm_cache.h>
42 #include <drm/drm_mem_util.h>
43 #include <drm/ttm/ttm_module.h>
44 #include <drm/ttm/ttm_bo_driver.h>
45 #include <drm/ttm/ttm_placement.h>
46 #include <drm/ttm/ttm_page_alloc.h>
47 
48 /**
49  * Allocates storage for pointers to the pages that back the ttm.
50  */
51 static void ttm_tt_alloc_page_directory(struct ttm_tt *ttm)
52 {
53 	ttm->pages = drm_calloc_large(ttm->num_pages, sizeof(void*));
54 }
55 
56 static void ttm_dma_tt_alloc_page_directory(struct ttm_dma_tt *ttm)
57 {
58 	ttm->ttm.pages = drm_calloc_large(ttm->ttm.num_pages,
59 					  sizeof(*ttm->ttm.pages) +
60 					  sizeof(*ttm->dma_address) +
61 					  sizeof(*ttm->cpu_address));
62 	ttm->cpu_address = (void *) (ttm->ttm.pages + ttm->ttm.num_pages);
63 	ttm->dma_address = (void *) (ttm->cpu_address + ttm->ttm.num_pages);
64 }
65 
66 #ifdef CONFIG_X86
67 static inline int ttm_tt_set_page_caching(struct page *p,
68 					  enum ttm_caching_state c_old,
69 					  enum ttm_caching_state c_new)
70 {
71 	int ret = 0;
72 
73 	if (PageHighMem(p))
74 		return 0;
75 
76 	if (c_old != tt_cached) {
77 		/* p isn't in the default caching state, set it to
78 		 * writeback first to free its current memtype. */
79 
80 		ret = set_pages_wb(p, 1);
81 		if (ret)
82 			return ret;
83 	}
84 
85 	if (c_new == tt_wc)
86 		ret = set_memory_wc((unsigned long) page_address(p), 1);
87 	else if (c_new == tt_uncached)
88 		ret = set_pages_uc(p, 1);
89 
90 	return ret;
91 }
92 #else /* CONFIG_X86 */
93 static inline int ttm_tt_set_page_caching(struct page *p,
94 					  enum ttm_caching_state c_old,
95 					  enum ttm_caching_state c_new)
96 {
97 	return 0;
98 }
99 #endif /* CONFIG_X86 */
100 
101 /*
102  * Change caching policy for the linear kernel map
103  * for range of pages in a ttm.
104  */
105 
106 static int ttm_tt_set_caching(struct ttm_tt *ttm,
107 			      enum ttm_caching_state c_state)
108 {
109 	int i, j;
110 	struct page *cur_page;
111 	int ret;
112 
113 	if (ttm->caching_state == c_state)
114 		return 0;
115 
116 	if (ttm->state == tt_unpopulated) {
117 		/* Change caching but don't populate */
118 		ttm->caching_state = c_state;
119 		return 0;
120 	}
121 
122 	if (ttm->caching_state == tt_cached)
123 		drm_clflush_pages(ttm->pages, ttm->num_pages);
124 
125 	for (i = 0; i < ttm->num_pages; ++i) {
126 		cur_page = ttm->pages[i];
127 		if (likely(cur_page != NULL)) {
128 			ret = ttm_tt_set_page_caching(cur_page,
129 						      ttm->caching_state,
130 						      c_state);
131 			if (unlikely(ret != 0))
132 				goto out_err;
133 		}
134 	}
135 
136 	ttm->caching_state = c_state;
137 
138 	return 0;
139 
140 out_err:
141 	for (j = 0; j < i; ++j) {
142 		cur_page = ttm->pages[j];
143 		if (likely(cur_page != NULL)) {
144 			(void)ttm_tt_set_page_caching(cur_page, c_state,
145 						      ttm->caching_state);
146 		}
147 	}
148 
149 	return ret;
150 }
151 
152 int ttm_tt_set_placement_caching(struct ttm_tt *ttm, uint32_t placement)
153 {
154 	enum ttm_caching_state state;
155 
156 	if (placement & TTM_PL_FLAG_WC)
157 		state = tt_wc;
158 	else if (placement & TTM_PL_FLAG_UNCACHED)
159 		state = tt_uncached;
160 	else
161 		state = tt_cached;
162 
163 	return ttm_tt_set_caching(ttm, state);
164 }
165 EXPORT_SYMBOL(ttm_tt_set_placement_caching);
166 
167 void ttm_tt_destroy(struct ttm_tt *ttm)
168 {
169 	if (unlikely(ttm == NULL))
170 		return;
171 
172 	if (ttm->state == tt_bound) {
173 		ttm_tt_unbind(ttm);
174 	}
175 
176 	if (ttm->state == tt_unbound)
177 		ttm_tt_unpopulate(ttm);
178 
179 	if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTENT_SWAP) &&
180 	    ttm->swap_storage)
181 		fput(ttm->swap_storage);
182 
183 	ttm->swap_storage = NULL;
184 	ttm->func->destroy(ttm);
185 }
186 
187 int ttm_tt_init(struct ttm_tt *ttm, struct ttm_bo_device *bdev,
188 		unsigned long size, uint32_t page_flags,
189 		struct page *dummy_read_page)
190 {
191 	ttm->bdev = bdev;
192 	ttm->glob = bdev->glob;
193 	ttm->num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
194 	ttm->caching_state = tt_cached;
195 	ttm->page_flags = page_flags;
196 	ttm->dummy_read_page = dummy_read_page;
197 	ttm->state = tt_unpopulated;
198 	ttm->swap_storage = NULL;
199 
200 	ttm_tt_alloc_page_directory(ttm);
201 	if (!ttm->pages) {
202 		ttm_tt_destroy(ttm);
203 		pr_err("Failed allocating page table\n");
204 		return -ENOMEM;
205 	}
206 	return 0;
207 }
208 EXPORT_SYMBOL(ttm_tt_init);
209 
210 void ttm_tt_fini(struct ttm_tt *ttm)
211 {
212 	drm_free_large(ttm->pages);
213 	ttm->pages = NULL;
214 }
215 EXPORT_SYMBOL(ttm_tt_fini);
216 
217 int ttm_dma_tt_init(struct ttm_dma_tt *ttm_dma, struct ttm_bo_device *bdev,
218 		unsigned long size, uint32_t page_flags,
219 		struct page *dummy_read_page)
220 {
221 	struct ttm_tt *ttm = &ttm_dma->ttm;
222 
223 	ttm->bdev = bdev;
224 	ttm->glob = bdev->glob;
225 	ttm->num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
226 	ttm->caching_state = tt_cached;
227 	ttm->page_flags = page_flags;
228 	ttm->dummy_read_page = dummy_read_page;
229 	ttm->state = tt_unpopulated;
230 	ttm->swap_storage = NULL;
231 
232 	INIT_LIST_HEAD(&ttm_dma->pages_list);
233 	ttm_dma_tt_alloc_page_directory(ttm_dma);
234 	if (!ttm->pages) {
235 		ttm_tt_destroy(ttm);
236 		pr_err("Failed allocating page table\n");
237 		return -ENOMEM;
238 	}
239 	return 0;
240 }
241 EXPORT_SYMBOL(ttm_dma_tt_init);
242 
243 void ttm_dma_tt_fini(struct ttm_dma_tt *ttm_dma)
244 {
245 	struct ttm_tt *ttm = &ttm_dma->ttm;
246 
247 	drm_free_large(ttm->pages);
248 	ttm->pages = NULL;
249 	ttm_dma->cpu_address = NULL;
250 	ttm_dma->dma_address = NULL;
251 }
252 EXPORT_SYMBOL(ttm_dma_tt_fini);
253 
254 void ttm_tt_unbind(struct ttm_tt *ttm)
255 {
256 	int ret;
257 
258 	if (ttm->state == tt_bound) {
259 		ret = ttm->func->unbind(ttm);
260 		BUG_ON(ret);
261 		ttm->state = tt_unbound;
262 	}
263 }
264 
265 int ttm_tt_bind(struct ttm_tt *ttm, struct ttm_mem_reg *bo_mem)
266 {
267 	int ret = 0;
268 
269 	if (!ttm)
270 		return -EINVAL;
271 
272 	if (ttm->state == tt_bound)
273 		return 0;
274 
275 	ret = ttm->bdev->driver->ttm_tt_populate(ttm);
276 	if (ret)
277 		return ret;
278 
279 	ret = ttm->func->bind(ttm, bo_mem);
280 	if (unlikely(ret != 0))
281 		return ret;
282 
283 	ttm->state = tt_bound;
284 
285 	return 0;
286 }
287 EXPORT_SYMBOL(ttm_tt_bind);
288 
289 int ttm_tt_swapin(struct ttm_tt *ttm)
290 {
291 	struct address_space *swap_space;
292 	struct file *swap_storage;
293 	struct page *from_page;
294 	struct page *to_page;
295 	int i;
296 	int ret = -ENOMEM;
297 
298 	swap_storage = ttm->swap_storage;
299 	BUG_ON(swap_storage == NULL);
300 
301 	swap_space = file_inode(swap_storage)->i_mapping;
302 
303 	for (i = 0; i < ttm->num_pages; ++i) {
304 		from_page = shmem_read_mapping_page(swap_space, i);
305 		if (IS_ERR(from_page)) {
306 			ret = PTR_ERR(from_page);
307 			goto out_err;
308 		}
309 		to_page = ttm->pages[i];
310 		if (unlikely(to_page == NULL))
311 			goto out_err;
312 
313 		copy_highpage(to_page, from_page);
314 		page_cache_release(from_page);
315 	}
316 
317 	if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTENT_SWAP))
318 		fput(swap_storage);
319 	ttm->swap_storage = NULL;
320 	ttm->page_flags &= ~TTM_PAGE_FLAG_SWAPPED;
321 
322 	return 0;
323 out_err:
324 	return ret;
325 }
326 
327 int ttm_tt_swapout(struct ttm_tt *ttm, struct file *persistent_swap_storage)
328 {
329 	struct address_space *swap_space;
330 	struct file *swap_storage;
331 	struct page *from_page;
332 	struct page *to_page;
333 	int i;
334 	int ret = -ENOMEM;
335 
336 	BUG_ON(ttm->state != tt_unbound && ttm->state != tt_unpopulated);
337 	BUG_ON(ttm->caching_state != tt_cached);
338 
339 	if (!persistent_swap_storage) {
340 		swap_storage = shmem_file_setup("ttm swap",
341 						ttm->num_pages << PAGE_SHIFT,
342 						0);
343 		if (unlikely(IS_ERR(swap_storage))) {
344 			pr_err("Failed allocating swap storage\n");
345 			return PTR_ERR(swap_storage);
346 		}
347 	} else
348 		swap_storage = persistent_swap_storage;
349 
350 	swap_space = file_inode(swap_storage)->i_mapping;
351 
352 	for (i = 0; i < ttm->num_pages; ++i) {
353 		from_page = ttm->pages[i];
354 		if (unlikely(from_page == NULL))
355 			continue;
356 		to_page = shmem_read_mapping_page(swap_space, i);
357 		if (unlikely(IS_ERR(to_page))) {
358 			ret = PTR_ERR(to_page);
359 			goto out_err;
360 		}
361 		copy_highpage(to_page, from_page);
362 		set_page_dirty(to_page);
363 		mark_page_accessed(to_page);
364 		page_cache_release(to_page);
365 	}
366 
367 	ttm_tt_unpopulate(ttm);
368 	ttm->swap_storage = swap_storage;
369 	ttm->page_flags |= TTM_PAGE_FLAG_SWAPPED;
370 	if (persistent_swap_storage)
371 		ttm->page_flags |= TTM_PAGE_FLAG_PERSISTENT_SWAP;
372 
373 	return 0;
374 out_err:
375 	if (!persistent_swap_storage)
376 		fput(swap_storage);
377 
378 	return ret;
379 }
380 
381 static void ttm_tt_clear_mapping(struct ttm_tt *ttm)
382 {
383 	pgoff_t i;
384 	struct page **page = ttm->pages;
385 
386 	if (ttm->page_flags & TTM_PAGE_FLAG_SG)
387 		return;
388 
389 	for (i = 0; i < ttm->num_pages; ++i) {
390 		(*page)->mapping = NULL;
391 		(*page++)->index = 0;
392 	}
393 }
394 
395 void ttm_tt_unpopulate(struct ttm_tt *ttm)
396 {
397 	if (ttm->state == tt_unpopulated)
398 		return;
399 
400 	ttm_tt_clear_mapping(ttm);
401 	ttm->bdev->driver->ttm_tt_unpopulate(ttm);
402 }
403