xref: /openbmc/linux/drivers/gpu/drm/ttm/ttm_tt.c (revision 4f6cce39)
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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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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 	ttm->dma_address = (void *) (ttm->ttm.pages + ttm->ttm.num_pages);
62 }
63 
64 #ifdef CONFIG_X86
65 static inline int ttm_tt_set_page_caching(struct page *p,
66 					  enum ttm_caching_state c_old,
67 					  enum ttm_caching_state c_new)
68 {
69 	int ret = 0;
70 
71 	if (PageHighMem(p))
72 		return 0;
73 
74 	if (c_old != tt_cached) {
75 		/* p isn't in the default caching state, set it to
76 		 * writeback first to free its current memtype. */
77 
78 		ret = set_pages_wb(p, 1);
79 		if (ret)
80 			return ret;
81 	}
82 
83 	if (c_new == tt_wc)
84 		ret = set_memory_wc((unsigned long) page_address(p), 1);
85 	else if (c_new == tt_uncached)
86 		ret = set_pages_uc(p, 1);
87 
88 	return ret;
89 }
90 #else /* CONFIG_X86 */
91 static inline int ttm_tt_set_page_caching(struct page *p,
92 					  enum ttm_caching_state c_old,
93 					  enum ttm_caching_state c_new)
94 {
95 	return 0;
96 }
97 #endif /* CONFIG_X86 */
98 
99 /*
100  * Change caching policy for the linear kernel map
101  * for range of pages in a ttm.
102  */
103 
104 static int ttm_tt_set_caching(struct ttm_tt *ttm,
105 			      enum ttm_caching_state c_state)
106 {
107 	int i, j;
108 	struct page *cur_page;
109 	int ret;
110 
111 	if (ttm->caching_state == c_state)
112 		return 0;
113 
114 	if (ttm->state == tt_unpopulated) {
115 		/* Change caching but don't populate */
116 		ttm->caching_state = c_state;
117 		return 0;
118 	}
119 
120 	if (ttm->caching_state == tt_cached)
121 		drm_clflush_pages(ttm->pages, ttm->num_pages);
122 
123 	for (i = 0; i < ttm->num_pages; ++i) {
124 		cur_page = ttm->pages[i];
125 		if (likely(cur_page != NULL)) {
126 			ret = ttm_tt_set_page_caching(cur_page,
127 						      ttm->caching_state,
128 						      c_state);
129 			if (unlikely(ret != 0))
130 				goto out_err;
131 		}
132 	}
133 
134 	ttm->caching_state = c_state;
135 
136 	return 0;
137 
138 out_err:
139 	for (j = 0; j < i; ++j) {
140 		cur_page = ttm->pages[j];
141 		if (likely(cur_page != NULL)) {
142 			(void)ttm_tt_set_page_caching(cur_page, c_state,
143 						      ttm->caching_state);
144 		}
145 	}
146 
147 	return ret;
148 }
149 
150 int ttm_tt_set_placement_caching(struct ttm_tt *ttm, uint32_t placement)
151 {
152 	enum ttm_caching_state state;
153 
154 	if (placement & TTM_PL_FLAG_WC)
155 		state = tt_wc;
156 	else if (placement & TTM_PL_FLAG_UNCACHED)
157 		state = tt_uncached;
158 	else
159 		state = tt_cached;
160 
161 	return ttm_tt_set_caching(ttm, state);
162 }
163 EXPORT_SYMBOL(ttm_tt_set_placement_caching);
164 
165 void ttm_tt_destroy(struct ttm_tt *ttm)
166 {
167 	if (ttm == NULL)
168 		return;
169 
170 	ttm_tt_unbind(ttm);
171 
172 	if (ttm->state == tt_unbound)
173 		ttm_tt_unpopulate(ttm);
174 
175 	if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTENT_SWAP) &&
176 	    ttm->swap_storage)
177 		fput(ttm->swap_storage);
178 
179 	ttm->swap_storage = NULL;
180 	ttm->func->destroy(ttm);
181 }
182 
183 int ttm_tt_init(struct ttm_tt *ttm, struct ttm_bo_device *bdev,
184 		unsigned long size, uint32_t page_flags,
185 		struct page *dummy_read_page)
186 {
187 	ttm->bdev = bdev;
188 	ttm->glob = bdev->glob;
189 	ttm->num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
190 	ttm->caching_state = tt_cached;
191 	ttm->page_flags = page_flags;
192 	ttm->dummy_read_page = dummy_read_page;
193 	ttm->state = tt_unpopulated;
194 	ttm->swap_storage = NULL;
195 
196 	ttm_tt_alloc_page_directory(ttm);
197 	if (!ttm->pages) {
198 		ttm_tt_destroy(ttm);
199 		pr_err("Failed allocating page table\n");
200 		return -ENOMEM;
201 	}
202 	return 0;
203 }
204 EXPORT_SYMBOL(ttm_tt_init);
205 
206 void ttm_tt_fini(struct ttm_tt *ttm)
207 {
208 	drm_free_large(ttm->pages);
209 	ttm->pages = NULL;
210 }
211 EXPORT_SYMBOL(ttm_tt_fini);
212 
213 int ttm_dma_tt_init(struct ttm_dma_tt *ttm_dma, struct ttm_bo_device *bdev,
214 		unsigned long size, uint32_t page_flags,
215 		struct page *dummy_read_page)
216 {
217 	struct ttm_tt *ttm = &ttm_dma->ttm;
218 
219 	ttm->bdev = bdev;
220 	ttm->glob = bdev->glob;
221 	ttm->num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
222 	ttm->caching_state = tt_cached;
223 	ttm->page_flags = page_flags;
224 	ttm->dummy_read_page = dummy_read_page;
225 	ttm->state = tt_unpopulated;
226 	ttm->swap_storage = NULL;
227 
228 	INIT_LIST_HEAD(&ttm_dma->pages_list);
229 	ttm_dma_tt_alloc_page_directory(ttm_dma);
230 	if (!ttm->pages) {
231 		ttm_tt_destroy(ttm);
232 		pr_err("Failed allocating page table\n");
233 		return -ENOMEM;
234 	}
235 	return 0;
236 }
237 EXPORT_SYMBOL(ttm_dma_tt_init);
238 
239 void ttm_dma_tt_fini(struct ttm_dma_tt *ttm_dma)
240 {
241 	struct ttm_tt *ttm = &ttm_dma->ttm;
242 
243 	drm_free_large(ttm->pages);
244 	ttm->pages = NULL;
245 	ttm_dma->dma_address = NULL;
246 }
247 EXPORT_SYMBOL(ttm_dma_tt_fini);
248 
249 void ttm_tt_unbind(struct ttm_tt *ttm)
250 {
251 	int ret;
252 
253 	if (ttm->state == tt_bound) {
254 		ret = ttm->func->unbind(ttm);
255 		BUG_ON(ret);
256 		ttm->state = tt_unbound;
257 	}
258 }
259 
260 int ttm_tt_bind(struct ttm_tt *ttm, struct ttm_mem_reg *bo_mem)
261 {
262 	int ret = 0;
263 
264 	if (!ttm)
265 		return -EINVAL;
266 
267 	if (ttm->state == tt_bound)
268 		return 0;
269 
270 	ret = ttm->bdev->driver->ttm_tt_populate(ttm);
271 	if (ret)
272 		return ret;
273 
274 	ret = ttm->func->bind(ttm, bo_mem);
275 	if (unlikely(ret != 0))
276 		return ret;
277 
278 	ttm->state = tt_bound;
279 
280 	return 0;
281 }
282 EXPORT_SYMBOL(ttm_tt_bind);
283 
284 int ttm_tt_swapin(struct ttm_tt *ttm)
285 {
286 	struct address_space *swap_space;
287 	struct file *swap_storage;
288 	struct page *from_page;
289 	struct page *to_page;
290 	int i;
291 	int ret = -ENOMEM;
292 
293 	swap_storage = ttm->swap_storage;
294 	BUG_ON(swap_storage == NULL);
295 
296 	swap_space = swap_storage->f_mapping;
297 
298 	for (i = 0; i < ttm->num_pages; ++i) {
299 		from_page = shmem_read_mapping_page(swap_space, i);
300 		if (IS_ERR(from_page)) {
301 			ret = PTR_ERR(from_page);
302 			goto out_err;
303 		}
304 		to_page = ttm->pages[i];
305 		if (unlikely(to_page == NULL))
306 			goto out_err;
307 
308 		copy_highpage(to_page, from_page);
309 		put_page(from_page);
310 	}
311 
312 	if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTENT_SWAP))
313 		fput(swap_storage);
314 	ttm->swap_storage = NULL;
315 	ttm->page_flags &= ~TTM_PAGE_FLAG_SWAPPED;
316 
317 	return 0;
318 out_err:
319 	return ret;
320 }
321 
322 int ttm_tt_swapout(struct ttm_tt *ttm, struct file *persistent_swap_storage)
323 {
324 	struct address_space *swap_space;
325 	struct file *swap_storage;
326 	struct page *from_page;
327 	struct page *to_page;
328 	int i;
329 	int ret = -ENOMEM;
330 
331 	BUG_ON(ttm->state != tt_unbound && ttm->state != tt_unpopulated);
332 	BUG_ON(ttm->caching_state != tt_cached);
333 
334 	if (!persistent_swap_storage) {
335 		swap_storage = shmem_file_setup("ttm swap",
336 						ttm->num_pages << PAGE_SHIFT,
337 						0);
338 		if (IS_ERR(swap_storage)) {
339 			pr_err("Failed allocating swap storage\n");
340 			return PTR_ERR(swap_storage);
341 		}
342 	} else
343 		swap_storage = persistent_swap_storage;
344 
345 	swap_space = swap_storage->f_mapping;
346 
347 	for (i = 0; i < ttm->num_pages; ++i) {
348 		from_page = ttm->pages[i];
349 		if (unlikely(from_page == NULL))
350 			continue;
351 		to_page = shmem_read_mapping_page(swap_space, i);
352 		if (IS_ERR(to_page)) {
353 			ret = PTR_ERR(to_page);
354 			goto out_err;
355 		}
356 		copy_highpage(to_page, from_page);
357 		set_page_dirty(to_page);
358 		mark_page_accessed(to_page);
359 		put_page(to_page);
360 	}
361 
362 	ttm_tt_unpopulate(ttm);
363 	ttm->swap_storage = swap_storage;
364 	ttm->page_flags |= TTM_PAGE_FLAG_SWAPPED;
365 	if (persistent_swap_storage)
366 		ttm->page_flags |= TTM_PAGE_FLAG_PERSISTENT_SWAP;
367 
368 	return 0;
369 out_err:
370 	if (!persistent_swap_storage)
371 		fput(swap_storage);
372 
373 	return ret;
374 }
375 
376 static void ttm_tt_clear_mapping(struct ttm_tt *ttm)
377 {
378 	pgoff_t i;
379 	struct page **page = ttm->pages;
380 
381 	if (ttm->page_flags & TTM_PAGE_FLAG_SG)
382 		return;
383 
384 	for (i = 0; i < ttm->num_pages; ++i) {
385 		(*page)->mapping = NULL;
386 		(*page++)->index = 0;
387 	}
388 }
389 
390 void ttm_tt_unpopulate(struct ttm_tt *ttm)
391 {
392 	if (ttm->state == tt_unpopulated)
393 		return;
394 
395 	ttm_tt_clear_mapping(ttm);
396 	ttm->bdev->driver->ttm_tt_unpopulate(ttm);
397 }
398