xref: /linux/include/drm/ttm/ttm_tt.h (revision 2eff01ee2881becc9daaa0d53477ec202136b1f4)
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27 #ifndef _TTM_TT_H_
28 #define _TTM_TT_H_
29 
30 #include <linux/pagemap.h>
31 #include <linux/types.h>
32 #include <drm/ttm/ttm_caching.h>
33 #include <drm/ttm/ttm_kmap_iter.h>
34 
35 struct ttm_device;
36 struct ttm_tt;
37 struct ttm_resource;
38 struct ttm_buffer_object;
39 struct ttm_operation_ctx;
40 
41 /**
42  * struct ttm_tt - This is a structure holding the pages, caching- and aperture
43  * binding status for a buffer object that isn't backed by fixed (VRAM / AGP)
44  * memory.
45  */
46 struct ttm_tt {
47 	/** @pages: Array of pages backing the data. */
48 	struct page **pages;
49 	/**
50 	 * @page_flags: The page flags.
51 	 *
52 	 * Supported values:
53 	 *
54 	 * TTM_TT_FLAG_SWAPPED: Set by TTM when the pages have been unpopulated
55 	 * and swapped out by TTM.  Calling ttm_tt_populate() will then swap the
56 	 * pages back in, and unset the flag. Drivers should in general never
57 	 * need to touch this.
58 	 *
59 	 * TTM_TT_FLAG_ZERO_ALLOC: Set if the pages will be zeroed on
60 	 * allocation.
61 	 *
62 	 * TTM_TT_FLAG_EXTERNAL: Set if the underlying pages were allocated
63 	 * externally, like with dma-buf or userptr. This effectively disables
64 	 * TTM swapping out such pages.  Also important is to prevent TTM from
65 	 * ever directly mapping these pages.
66 	 *
67 	 * Note that enum ttm_bo_type.ttm_bo_type_sg objects will always enable
68 	 * this flag.
69 	 *
70 	 * TTM_TT_FLAG_EXTERNAL_MAPPABLE: Same behaviour as
71 	 * TTM_TT_FLAG_EXTERNAL, but with the reduced restriction that it is
72 	 * still valid to use TTM to map the pages directly. This is useful when
73 	 * implementing a ttm_tt backend which still allocates driver owned
74 	 * pages underneath(say with shmem).
75 	 *
76 	 * Note that since this also implies TTM_TT_FLAG_EXTERNAL, the usage
77 	 * here should always be:
78 	 *
79 	 *   page_flags = TTM_TT_FLAG_EXTERNAL |
80 	 *		  TTM_TT_FLAG_EXTERNAL_MAPPABLE;
81 	 *
82 	 * TTM_TT_FLAG_DECRYPTED: The mapped ttm pages should be marked as
83 	 * not encrypted. The framework will try to match what the dma layer
84 	 * is doing, but note that it is a little fragile because ttm page
85 	 * fault handling abuses the DMA api a bit and dma_map_attrs can't be
86 	 * used to assure pgprot always matches.
87 	 *
88 	 * TTM_TT_FLAG_PRIV_POPULATED: TTM internal only. DO NOT USE. This is
89 	 * set by TTM after ttm_tt_populate() has successfully returned, and is
90 	 * then unset when TTM calls ttm_tt_unpopulate().
91 	 */
92 #define TTM_TT_FLAG_SWAPPED		BIT(0)
93 #define TTM_TT_FLAG_ZERO_ALLOC		BIT(1)
94 #define TTM_TT_FLAG_EXTERNAL		BIT(2)
95 #define TTM_TT_FLAG_EXTERNAL_MAPPABLE	BIT(3)
96 #define TTM_TT_FLAG_DECRYPTED		BIT(4)
97 
98 #define TTM_TT_FLAG_PRIV_POPULATED	BIT(5)
99 	uint32_t page_flags;
100 	/** @num_pages: Number of pages in the page array. */
101 	uint32_t num_pages;
102 	/** @sg: for SG objects via dma-buf. */
103 	struct sg_table *sg;
104 	/** @dma_address: The DMA (bus) addresses of the pages. */
105 	dma_addr_t *dma_address;
106 	/** @swap_storage: Pointer to shmem struct file for swap storage. */
107 	struct file *swap_storage;
108 	/**
109 	 * @caching: The current caching state of the pages, see enum
110 	 * ttm_caching.
111 	 */
112 	enum ttm_caching caching;
113 };
114 
115 /**
116  * struct ttm_kmap_iter_tt - Specialization of a mappig iterator for a tt.
117  * @base: Embedded struct ttm_kmap_iter providing the usage interface
118  * @tt: Cached struct ttm_tt.
119  * @prot: Cached page protection for mapping.
120  */
121 struct ttm_kmap_iter_tt {
122 	struct ttm_kmap_iter base;
123 	struct ttm_tt *tt;
124 	pgprot_t prot;
125 };
126 
127 static inline bool ttm_tt_is_populated(struct ttm_tt *tt)
128 {
129 	return tt->page_flags & TTM_TT_FLAG_PRIV_POPULATED;
130 }
131 
132 static inline bool ttm_tt_is_swapped(const struct ttm_tt *tt)
133 {
134 	return tt->page_flags & TTM_TT_FLAG_SWAPPED;
135 }
136 
137 /**
138  * ttm_tt_create
139  *
140  * @bo: pointer to a struct ttm_buffer_object
141  * @zero_alloc: true if allocated pages needs to be zeroed
142  *
143  * Make sure we have a TTM structure allocated for the given BO.
144  * No pages are actually allocated.
145  */
146 int ttm_tt_create(struct ttm_buffer_object *bo, bool zero_alloc);
147 
148 /**
149  * ttm_tt_init
150  *
151  * @ttm: The struct ttm_tt.
152  * @bo: The buffer object we create the ttm for.
153  * @page_flags: Page flags as identified by TTM_TT_FLAG_XX flags.
154  * @caching: the desired caching state of the pages
155  * @extra_pages: Extra pages needed for the driver.
156  *
157  * Create a struct ttm_tt to back data with system memory pages.
158  * No pages are actually allocated.
159  * Returns:
160  * NULL: Out of memory.
161  */
162 int ttm_tt_init(struct ttm_tt *ttm, struct ttm_buffer_object *bo,
163 		uint32_t page_flags, enum ttm_caching caching,
164 		unsigned long extra_pages);
165 int ttm_sg_tt_init(struct ttm_tt *ttm_dma, struct ttm_buffer_object *bo,
166 		   uint32_t page_flags, enum ttm_caching caching);
167 
168 /**
169  * ttm_tt_fini
170  *
171  * @ttm: the ttm_tt structure.
172  *
173  * Free memory of ttm_tt structure
174  */
175 void ttm_tt_fini(struct ttm_tt *ttm);
176 
177 /**
178  * ttm_tt_destroy:
179  *
180  * @bdev: the ttm_device this object belongs to
181  * @ttm: The struct ttm_tt.
182  *
183  * Unbind, unpopulate and destroy common struct ttm_tt.
184  */
185 void ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *ttm);
186 
187 /**
188  * ttm_tt_swapin:
189  *
190  * @ttm: The struct ttm_tt.
191  *
192  * Swap in a previously swap out ttm_tt.
193  */
194 int ttm_tt_swapin(struct ttm_tt *ttm);
195 int ttm_tt_swapout(struct ttm_device *bdev, struct ttm_tt *ttm,
196 		   gfp_t gfp_flags);
197 
198 /**
199  * ttm_tt_populate - allocate pages for a ttm
200  *
201  * @bdev: the ttm_device this object belongs to
202  * @ttm: Pointer to the ttm_tt structure
203  * @ctx: operation context for populating the tt object.
204  *
205  * Calls the driver method to allocate pages for a ttm
206  */
207 int ttm_tt_populate(struct ttm_device *bdev, struct ttm_tt *ttm,
208 		    struct ttm_operation_ctx *ctx);
209 
210 /**
211  * ttm_tt_unpopulate - free pages from a ttm
212  *
213  * @bdev: the ttm_device this object belongs to
214  * @ttm: Pointer to the ttm_tt structure
215  *
216  * Calls the driver method to free all pages from a ttm
217  */
218 void ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm);
219 
220 /**
221  * ttm_tt_mark_for_clear - Mark pages for clearing on populate.
222  *
223  * @ttm: Pointer to the ttm_tt structure
224  *
225  * Marks pages for clearing so that the next time the page vector is
226  * populated, the pages will be cleared.
227  */
228 static inline void ttm_tt_mark_for_clear(struct ttm_tt *ttm)
229 {
230 	ttm->page_flags |= TTM_TT_FLAG_ZERO_ALLOC;
231 }
232 
233 void ttm_tt_mgr_init(unsigned long num_pages, unsigned long num_dma32_pages);
234 
235 struct ttm_kmap_iter *ttm_kmap_iter_tt_init(struct ttm_kmap_iter_tt *iter_tt,
236 					    struct ttm_tt *tt);
237 unsigned long ttm_tt_pages_limit(void);
238 #if IS_ENABLED(CONFIG_AGP)
239 #include <linux/agp_backend.h>
240 
241 /**
242  * ttm_agp_tt_create
243  *
244  * @bo: Buffer object we allocate the ttm for.
245  * @bridge: The agp bridge this device is sitting on.
246  * @page_flags: Page flags as identified by TTM_TT_FLAG_XX flags.
247  *
248  *
249  * Create a TTM backend that uses the indicated AGP bridge as an aperture
250  * for TT memory. This function uses the linux agpgart interface to
251  * bind and unbind memory backing a ttm_tt.
252  */
253 struct ttm_tt *ttm_agp_tt_create(struct ttm_buffer_object *bo,
254 				 struct agp_bridge_data *bridge,
255 				 uint32_t page_flags);
256 int ttm_agp_bind(struct ttm_tt *ttm, struct ttm_resource *bo_mem);
257 void ttm_agp_unbind(struct ttm_tt *ttm);
258 void ttm_agp_destroy(struct ttm_tt *ttm);
259 bool ttm_agp_is_bound(struct ttm_tt *ttm);
260 #endif
261 
262 #endif
263