xref: /openbmc/linux/drivers/gpu/drm/ttm/ttm_tt.c (revision a2fb4d78)
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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, sizeof(void*));
59 	ttm->dma_address = drm_calloc_large(ttm->ttm.num_pages,
60 					    sizeof(*ttm->dma_address));
61 }
62 
63 #ifdef CONFIG_X86
64 static inline int ttm_tt_set_page_caching(struct page *p,
65 					  enum ttm_caching_state c_old,
66 					  enum ttm_caching_state c_new)
67 {
68 	int ret = 0;
69 
70 	if (PageHighMem(p))
71 		return 0;
72 
73 	if (c_old != tt_cached) {
74 		/* p isn't in the default caching state, set it to
75 		 * writeback first to free its current memtype. */
76 
77 		ret = set_pages_wb(p, 1);
78 		if (ret)
79 			return ret;
80 	}
81 
82 	if (c_new == tt_wc)
83 		ret = set_memory_wc((unsigned long) page_address(p), 1);
84 	else if (c_new == tt_uncached)
85 		ret = set_pages_uc(p, 1);
86 
87 	return ret;
88 }
89 #else /* CONFIG_X86 */
90 static inline int ttm_tt_set_page_caching(struct page *p,
91 					  enum ttm_caching_state c_old,
92 					  enum ttm_caching_state c_new)
93 {
94 	return 0;
95 }
96 #endif /* CONFIG_X86 */
97 
98 /*
99  * Change caching policy for the linear kernel map
100  * for range of pages in a ttm.
101  */
102 
103 static int ttm_tt_set_caching(struct ttm_tt *ttm,
104 			      enum ttm_caching_state c_state)
105 {
106 	int i, j;
107 	struct page *cur_page;
108 	int ret;
109 
110 	if (ttm->caching_state == c_state)
111 		return 0;
112 
113 	if (ttm->state == tt_unpopulated) {
114 		/* Change caching but don't populate */
115 		ttm->caching_state = c_state;
116 		return 0;
117 	}
118 
119 	if (ttm->caching_state == tt_cached)
120 		drm_clflush_pages(ttm->pages, ttm->num_pages);
121 
122 	for (i = 0; i < ttm->num_pages; ++i) {
123 		cur_page = ttm->pages[i];
124 		if (likely(cur_page != NULL)) {
125 			ret = ttm_tt_set_page_caching(cur_page,
126 						      ttm->caching_state,
127 						      c_state);
128 			if (unlikely(ret != 0))
129 				goto out_err;
130 		}
131 	}
132 
133 	ttm->caching_state = c_state;
134 
135 	return 0;
136 
137 out_err:
138 	for (j = 0; j < i; ++j) {
139 		cur_page = ttm->pages[j];
140 		if (likely(cur_page != NULL)) {
141 			(void)ttm_tt_set_page_caching(cur_page, c_state,
142 						      ttm->caching_state);
143 		}
144 	}
145 
146 	return ret;
147 }
148 
149 int ttm_tt_set_placement_caching(struct ttm_tt *ttm, uint32_t placement)
150 {
151 	enum ttm_caching_state state;
152 
153 	if (placement & TTM_PL_FLAG_WC)
154 		state = tt_wc;
155 	else if (placement & TTM_PL_FLAG_UNCACHED)
156 		state = tt_uncached;
157 	else
158 		state = tt_cached;
159 
160 	return ttm_tt_set_caching(ttm, state);
161 }
162 EXPORT_SYMBOL(ttm_tt_set_placement_caching);
163 
164 void ttm_tt_destroy(struct ttm_tt *ttm)
165 {
166 	if (unlikely(ttm == NULL))
167 		return;
168 
169 	if (ttm->state == tt_bound) {
170 		ttm_tt_unbind(ttm);
171 	}
172 
173 	if (ttm->state == tt_unbound)
174 		ttm_tt_unpopulate(ttm);
175 
176 	if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTENT_SWAP) &&
177 	    ttm->swap_storage)
178 		fput(ttm->swap_storage);
179 
180 	ttm->swap_storage = NULL;
181 	ttm->func->destroy(ttm);
182 }
183 
184 int ttm_tt_init(struct ttm_tt *ttm, struct ttm_bo_device *bdev,
185 		unsigned long size, uint32_t page_flags,
186 		struct page *dummy_read_page)
187 {
188 	ttm->bdev = bdev;
189 	ttm->glob = bdev->glob;
190 	ttm->num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
191 	ttm->caching_state = tt_cached;
192 	ttm->page_flags = page_flags;
193 	ttm->dummy_read_page = dummy_read_page;
194 	ttm->state = tt_unpopulated;
195 	ttm->swap_storage = NULL;
196 
197 	ttm_tt_alloc_page_directory(ttm);
198 	if (!ttm->pages) {
199 		ttm_tt_destroy(ttm);
200 		pr_err("Failed allocating page table\n");
201 		return -ENOMEM;
202 	}
203 	return 0;
204 }
205 EXPORT_SYMBOL(ttm_tt_init);
206 
207 void ttm_tt_fini(struct ttm_tt *ttm)
208 {
209 	drm_free_large(ttm->pages);
210 	ttm->pages = NULL;
211 }
212 EXPORT_SYMBOL(ttm_tt_fini);
213 
214 int ttm_dma_tt_init(struct ttm_dma_tt *ttm_dma, struct ttm_bo_device *bdev,
215 		unsigned long size, uint32_t page_flags,
216 		struct page *dummy_read_page)
217 {
218 	struct ttm_tt *ttm = &ttm_dma->ttm;
219 
220 	ttm->bdev = bdev;
221 	ttm->glob = bdev->glob;
222 	ttm->num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
223 	ttm->caching_state = tt_cached;
224 	ttm->page_flags = page_flags;
225 	ttm->dummy_read_page = dummy_read_page;
226 	ttm->state = tt_unpopulated;
227 	ttm->swap_storage = NULL;
228 
229 	INIT_LIST_HEAD(&ttm_dma->pages_list);
230 	ttm_dma_tt_alloc_page_directory(ttm_dma);
231 	if (!ttm->pages || !ttm_dma->dma_address) {
232 		ttm_tt_destroy(ttm);
233 		pr_err("Failed allocating page table\n");
234 		return -ENOMEM;
235 	}
236 	return 0;
237 }
238 EXPORT_SYMBOL(ttm_dma_tt_init);
239 
240 void ttm_dma_tt_fini(struct ttm_dma_tt *ttm_dma)
241 {
242 	struct ttm_tt *ttm = &ttm_dma->ttm;
243 
244 	drm_free_large(ttm->pages);
245 	ttm->pages = NULL;
246 	drm_free_large(ttm_dma->dma_address);
247 	ttm_dma->dma_address = NULL;
248 }
249 EXPORT_SYMBOL(ttm_dma_tt_fini);
250 
251 void ttm_tt_unbind(struct ttm_tt *ttm)
252 {
253 	int ret;
254 
255 	if (ttm->state == tt_bound) {
256 		ret = ttm->func->unbind(ttm);
257 		BUG_ON(ret);
258 		ttm->state = tt_unbound;
259 	}
260 }
261 
262 int ttm_tt_bind(struct ttm_tt *ttm, struct ttm_mem_reg *bo_mem)
263 {
264 	int ret = 0;
265 
266 	if (!ttm)
267 		return -EINVAL;
268 
269 	if (ttm->state == tt_bound)
270 		return 0;
271 
272 	ret = ttm->bdev->driver->ttm_tt_populate(ttm);
273 	if (ret)
274 		return ret;
275 
276 	ret = ttm->func->bind(ttm, bo_mem);
277 	if (unlikely(ret != 0))
278 		return ret;
279 
280 	ttm->state = tt_bound;
281 
282 	return 0;
283 }
284 EXPORT_SYMBOL(ttm_tt_bind);
285 
286 int ttm_tt_swapin(struct ttm_tt *ttm)
287 {
288 	struct address_space *swap_space;
289 	struct file *swap_storage;
290 	struct page *from_page;
291 	struct page *to_page;
292 	int i;
293 	int ret = -ENOMEM;
294 
295 	swap_storage = ttm->swap_storage;
296 	BUG_ON(swap_storage == NULL);
297 
298 	swap_space = file_inode(swap_storage)->i_mapping;
299 
300 	for (i = 0; i < ttm->num_pages; ++i) {
301 		from_page = shmem_read_mapping_page(swap_space, i);
302 		if (IS_ERR(from_page)) {
303 			ret = PTR_ERR(from_page);
304 			goto out_err;
305 		}
306 		to_page = ttm->pages[i];
307 		if (unlikely(to_page == NULL))
308 			goto out_err;
309 
310 		copy_highpage(to_page, from_page);
311 		page_cache_release(from_page);
312 	}
313 
314 	if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTENT_SWAP))
315 		fput(swap_storage);
316 	ttm->swap_storage = NULL;
317 	ttm->page_flags &= ~TTM_PAGE_FLAG_SWAPPED;
318 
319 	return 0;
320 out_err:
321 	return ret;
322 }
323 
324 int ttm_tt_swapout(struct ttm_tt *ttm, struct file *persistent_swap_storage)
325 {
326 	struct address_space *swap_space;
327 	struct file *swap_storage;
328 	struct page *from_page;
329 	struct page *to_page;
330 	int i;
331 	int ret = -ENOMEM;
332 
333 	BUG_ON(ttm->state != tt_unbound && ttm->state != tt_unpopulated);
334 	BUG_ON(ttm->caching_state != tt_cached);
335 
336 	if (!persistent_swap_storage) {
337 		swap_storage = shmem_file_setup("ttm swap",
338 						ttm->num_pages << PAGE_SHIFT,
339 						0);
340 		if (unlikely(IS_ERR(swap_storage))) {
341 			pr_err("Failed allocating swap storage\n");
342 			return PTR_ERR(swap_storage);
343 		}
344 	} else
345 		swap_storage = persistent_swap_storage;
346 
347 	swap_space = file_inode(swap_storage)->i_mapping;
348 
349 	for (i = 0; i < ttm->num_pages; ++i) {
350 		from_page = ttm->pages[i];
351 		if (unlikely(from_page == NULL))
352 			continue;
353 		to_page = shmem_read_mapping_page(swap_space, i);
354 		if (unlikely(IS_ERR(to_page))) {
355 			ret = PTR_ERR(to_page);
356 			goto out_err;
357 		}
358 		copy_highpage(to_page, from_page);
359 		set_page_dirty(to_page);
360 		mark_page_accessed(to_page);
361 		page_cache_release(to_page);
362 	}
363 
364 	ttm_tt_unpopulate(ttm);
365 	ttm->swap_storage = swap_storage;
366 	ttm->page_flags |= TTM_PAGE_FLAG_SWAPPED;
367 	if (persistent_swap_storage)
368 		ttm->page_flags |= TTM_PAGE_FLAG_PERSISTENT_SWAP;
369 
370 	return 0;
371 out_err:
372 	if (!persistent_swap_storage)
373 		fput(swap_storage);
374 
375 	return ret;
376 }
377 
378 static void ttm_tt_clear_mapping(struct ttm_tt *ttm)
379 {
380 	pgoff_t i;
381 	struct page **page = ttm->pages;
382 
383 	if (ttm->page_flags & TTM_PAGE_FLAG_SG)
384 		return;
385 
386 	for (i = 0; i < ttm->num_pages; ++i) {
387 		(*page)->mapping = NULL;
388 		(*page++)->index = 0;
389 	}
390 }
391 
392 void ttm_tt_unpopulate(struct ttm_tt *ttm)
393 {
394 	if (ttm->state == tt_unpopulated)
395 		return;
396 
397 	ttm_tt_clear_mapping(ttm);
398 	ttm->bdev->driver->ttm_tt_unpopulate(ttm);
399 }
400