xref: /openbmc/linux/include/drm/ttm/ttm_tt.h (revision ac3cb6de)
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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_PRIV_POPULATED: TTM internal only. DO NOT USE. This is
83 	 * set by TTM after ttm_tt_populate() has successfully returned, and is
84 	 * then unset when TTM calls ttm_tt_unpopulate().
85 	 */
86 #define TTM_TT_FLAG_SWAPPED		BIT(0)
87 #define TTM_TT_FLAG_ZERO_ALLOC		BIT(1)
88 #define TTM_TT_FLAG_EXTERNAL		BIT(2)
89 #define TTM_TT_FLAG_EXTERNAL_MAPPABLE	BIT(3)
90 
91 #define TTM_TT_FLAG_PRIV_POPULATED	BIT(4)
92 	uint32_t page_flags;
93 	/** @num_pages: Number of pages in the page array. */
94 	uint32_t num_pages;
95 	/** @sg: for SG objects via dma-buf. */
96 	struct sg_table *sg;
97 	/** @dma_address: The DMA (bus) addresses of the pages. */
98 	dma_addr_t *dma_address;
99 	/** @swap_storage: Pointer to shmem struct file for swap storage. */
100 	struct file *swap_storage;
101 	/**
102 	 * @caching: The current caching state of the pages, see enum
103 	 * ttm_caching.
104 	 */
105 	enum ttm_caching caching;
106 };
107 
108 /**
109  * struct ttm_kmap_iter_tt - Specialization of a mappig iterator for a tt.
110  * @base: Embedded struct ttm_kmap_iter providing the usage interface
111  * @tt: Cached struct ttm_tt.
112  * @prot: Cached page protection for mapping.
113  */
114 struct ttm_kmap_iter_tt {
115 	struct ttm_kmap_iter base;
116 	struct ttm_tt *tt;
117 	pgprot_t prot;
118 };
119 
120 static inline bool ttm_tt_is_populated(struct ttm_tt *tt)
121 {
122 	return tt->page_flags & TTM_TT_FLAG_PRIV_POPULATED;
123 }
124 
125 /**
126  * ttm_tt_create
127  *
128  * @bo: pointer to a struct ttm_buffer_object
129  * @zero_alloc: true if allocated pages needs to be zeroed
130  *
131  * Make sure we have a TTM structure allocated for the given BO.
132  * No pages are actually allocated.
133  */
134 int ttm_tt_create(struct ttm_buffer_object *bo, bool zero_alloc);
135 
136 /**
137  * ttm_tt_init
138  *
139  * @ttm: The struct ttm_tt.
140  * @bo: The buffer object we create the ttm for.
141  * @page_flags: Page flags as identified by TTM_TT_FLAG_XX flags.
142  * @caching: the desired caching state of the pages
143  * @extra_pages: Extra pages needed for the driver.
144  *
145  * Create a struct ttm_tt to back data with system memory pages.
146  * No pages are actually allocated.
147  * Returns:
148  * NULL: Out of memory.
149  */
150 int ttm_tt_init(struct ttm_tt *ttm, struct ttm_buffer_object *bo,
151 		uint32_t page_flags, enum ttm_caching caching,
152 		unsigned long extra_pages);
153 int ttm_sg_tt_init(struct ttm_tt *ttm_dma, struct ttm_buffer_object *bo,
154 		   uint32_t page_flags, enum ttm_caching caching);
155 
156 /**
157  * ttm_tt_fini
158  *
159  * @ttm: the ttm_tt structure.
160  *
161  * Free memory of ttm_tt structure
162  */
163 void ttm_tt_fini(struct ttm_tt *ttm);
164 
165 /**
166  * ttm_tt_destroy:
167  *
168  * @bdev: the ttm_device this object belongs to
169  * @ttm: The struct ttm_tt.
170  *
171  * Unbind, unpopulate and destroy common struct ttm_tt.
172  */
173 void ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *ttm);
174 
175 /**
176  * ttm_tt_swapin:
177  *
178  * @ttm: The struct ttm_tt.
179  *
180  * Swap in a previously swap out ttm_tt.
181  */
182 int ttm_tt_swapin(struct ttm_tt *ttm);
183 int ttm_tt_swapout(struct ttm_device *bdev, struct ttm_tt *ttm,
184 		   gfp_t gfp_flags);
185 
186 /**
187  * ttm_tt_populate - allocate pages for a ttm
188  *
189  * @bdev: the ttm_device this object belongs to
190  * @ttm: Pointer to the ttm_tt structure
191  * @ctx: operation context for populating the tt object.
192  *
193  * Calls the driver method to allocate pages for a ttm
194  */
195 int ttm_tt_populate(struct ttm_device *bdev, struct ttm_tt *ttm,
196 		    struct ttm_operation_ctx *ctx);
197 
198 /**
199  * ttm_tt_unpopulate - free pages from a ttm
200  *
201  * @bdev: the ttm_device this object belongs to
202  * @ttm: Pointer to the ttm_tt structure
203  *
204  * Calls the driver method to free all pages from a ttm
205  */
206 void ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm);
207 
208 /**
209  * ttm_tt_mark_for_clear - Mark pages for clearing on populate.
210  *
211  * @ttm: Pointer to the ttm_tt structure
212  *
213  * Marks pages for clearing so that the next time the page vector is
214  * populated, the pages will be cleared.
215  */
216 static inline void ttm_tt_mark_for_clear(struct ttm_tt *ttm)
217 {
218 	ttm->page_flags |= TTM_TT_FLAG_ZERO_ALLOC;
219 }
220 
221 void ttm_tt_mgr_init(unsigned long num_pages, unsigned long num_dma32_pages);
222 
223 struct ttm_kmap_iter *ttm_kmap_iter_tt_init(struct ttm_kmap_iter_tt *iter_tt,
224 					    struct ttm_tt *tt);
225 unsigned long ttm_tt_pages_limit(void);
226 #if IS_ENABLED(CONFIG_AGP)
227 #include <linux/agp_backend.h>
228 
229 /**
230  * ttm_agp_tt_create
231  *
232  * @bo: Buffer object we allocate the ttm for.
233  * @bridge: The agp bridge this device is sitting on.
234  * @page_flags: Page flags as identified by TTM_TT_FLAG_XX flags.
235  *
236  *
237  * Create a TTM backend that uses the indicated AGP bridge as an aperture
238  * for TT memory. This function uses the linux agpgart interface to
239  * bind and unbind memory backing a ttm_tt.
240  */
241 struct ttm_tt *ttm_agp_tt_create(struct ttm_buffer_object *bo,
242 				 struct agp_bridge_data *bridge,
243 				 uint32_t page_flags);
244 int ttm_agp_bind(struct ttm_tt *ttm, struct ttm_resource *bo_mem);
245 void ttm_agp_unbind(struct ttm_tt *ttm);
246 void ttm_agp_destroy(struct ttm_tt *ttm);
247 bool ttm_agp_is_bound(struct ttm_tt *ttm);
248 #endif
249 
250 #endif
251