xref: /openbmc/linux/include/drm/ttm/ttm_tt.h (revision b830f94f)
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27 #ifndef _TTM_TT_H_
28 #define _TTM_TT_H_
29 
30 #include <linux/types.h>
31 
32 struct ttm_tt;
33 struct ttm_mem_reg;
34 struct ttm_buffer_object;
35 struct ttm_operation_ctx;
36 
37 #define TTM_PAGE_FLAG_WRITE           (1 << 3)
38 #define TTM_PAGE_FLAG_SWAPPED         (1 << 4)
39 #define TTM_PAGE_FLAG_PERSISTENT_SWAP (1 << 5)
40 #define TTM_PAGE_FLAG_ZERO_ALLOC      (1 << 6)
41 #define TTM_PAGE_FLAG_DMA32           (1 << 7)
42 #define TTM_PAGE_FLAG_SG              (1 << 8)
43 #define TTM_PAGE_FLAG_NO_RETRY	      (1 << 9)
44 
45 enum ttm_caching_state {
46 	tt_uncached,
47 	tt_wc,
48 	tt_cached
49 };
50 
51 struct ttm_backend_func {
52 	/**
53 	 * struct ttm_backend_func member bind
54 	 *
55 	 * @ttm: Pointer to a struct ttm_tt.
56 	 * @bo_mem: Pointer to a struct ttm_mem_reg describing the
57 	 * memory type and location for binding.
58 	 *
59 	 * Bind the backend pages into the aperture in the location
60 	 * indicated by @bo_mem. This function should be able to handle
61 	 * differences between aperture and system page sizes.
62 	 */
63 	int (*bind) (struct ttm_tt *ttm, struct ttm_mem_reg *bo_mem);
64 
65 	/**
66 	 * struct ttm_backend_func member unbind
67 	 *
68 	 * @ttm: Pointer to a struct ttm_tt.
69 	 *
70 	 * Unbind previously bound backend pages. This function should be
71 	 * able to handle differences between aperture and system page sizes.
72 	 */
73 	int (*unbind) (struct ttm_tt *ttm);
74 
75 	/**
76 	 * struct ttm_backend_func member destroy
77 	 *
78 	 * @ttm: Pointer to a struct ttm_tt.
79 	 *
80 	 * Destroy the backend. This will be call back from ttm_tt_destroy so
81 	 * don't call ttm_tt_destroy from the callback or infinite loop.
82 	 */
83 	void (*destroy) (struct ttm_tt *ttm);
84 };
85 
86 /**
87  * struct ttm_tt
88  *
89  * @bdev: Pointer to a struct ttm_bo_device.
90  * @func: Pointer to a struct ttm_backend_func that describes
91  * the backend methods.
92  * pointer.
93  * @pages: Array of pages backing the data.
94  * @num_pages: Number of pages in the page array.
95  * @bdev: Pointer to the current struct ttm_bo_device.
96  * @be: Pointer to the ttm backend.
97  * @swap_storage: Pointer to shmem struct file for swap storage.
98  * @caching_state: The current caching state of the pages.
99  * @state: The current binding state of the pages.
100  *
101  * This is a structure holding the pages, caching- and aperture binding
102  * status for a buffer object that isn't backed by fixed (VRAM / AGP)
103  * memory.
104  */
105 struct ttm_tt {
106 	struct ttm_bo_device *bdev;
107 	struct ttm_backend_func *func;
108 	struct page **pages;
109 	uint32_t page_flags;
110 	unsigned long num_pages;
111 	struct sg_table *sg; /* for SG objects via dma-buf */
112 	struct file *swap_storage;
113 	enum ttm_caching_state caching_state;
114 	enum {
115 		tt_bound,
116 		tt_unbound,
117 		tt_unpopulated,
118 	} state;
119 };
120 
121 /**
122  * struct ttm_dma_tt
123  *
124  * @ttm: Base ttm_tt struct.
125  * @dma_address: The DMA (bus) addresses of the pages
126  * @pages_list: used by some page allocation backend
127  *
128  * This is a structure holding the pages, caching- and aperture binding
129  * status for a buffer object that isn't backed by fixed (VRAM / AGP)
130  * memory.
131  */
132 struct ttm_dma_tt {
133 	struct ttm_tt ttm;
134 	dma_addr_t *dma_address;
135 	struct list_head pages_list;
136 };
137 
138 /**
139  * ttm_tt_create
140  *
141  * @bo: pointer to a struct ttm_buffer_object
142  * @zero_alloc: true if allocated pages needs to be zeroed
143  *
144  * Make sure we have a TTM structure allocated for the given BO.
145  * No pages are actually allocated.
146  */
147 int ttm_tt_create(struct ttm_buffer_object *bo, bool zero_alloc);
148 
149 /**
150  * ttm_tt_init
151  *
152  * @ttm: The struct ttm_tt.
153  * @bo: The buffer object we create the ttm for.
154  * @page_flags: Page flags as identified by TTM_PAGE_FLAG_XX flags.
155  *
156  * Create a struct ttm_tt to back data with system memory pages.
157  * No pages are actually allocated.
158  * Returns:
159  * NULL: Out of memory.
160  */
161 int ttm_tt_init(struct ttm_tt *ttm, struct ttm_buffer_object *bo,
162 		uint32_t page_flags);
163 int ttm_dma_tt_init(struct ttm_dma_tt *ttm_dma, struct ttm_buffer_object *bo,
164 		    uint32_t page_flags);
165 int ttm_sg_tt_init(struct ttm_dma_tt *ttm_dma, struct ttm_buffer_object *bo,
166 		   uint32_t page_flags);
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 void ttm_dma_tt_fini(struct ttm_dma_tt *ttm_dma);
177 
178 /**
179  * ttm_ttm_bind:
180  *
181  * @ttm: The struct ttm_tt containing backing pages.
182  * @bo_mem: The struct ttm_mem_reg identifying the binding location.
183  *
184  * Bind the pages of @ttm to an aperture location identified by @bo_mem
185  */
186 int ttm_tt_bind(struct ttm_tt *ttm, struct ttm_mem_reg *bo_mem,
187 		struct ttm_operation_ctx *ctx);
188 
189 /**
190  * ttm_ttm_destroy:
191  *
192  * @ttm: The struct ttm_tt.
193  *
194  * Unbind, unpopulate and destroy common struct ttm_tt.
195  */
196 void ttm_tt_destroy(struct ttm_tt *ttm);
197 
198 /**
199  * ttm_ttm_unbind:
200  *
201  * @ttm: The struct ttm_tt.
202  *
203  * Unbind a struct ttm_tt.
204  */
205 void ttm_tt_unbind(struct ttm_tt *ttm);
206 
207 /**
208  * ttm_tt_swapin:
209  *
210  * @ttm: The struct ttm_tt.
211  *
212  * Swap in a previously swap out ttm_tt.
213  */
214 int ttm_tt_swapin(struct ttm_tt *ttm);
215 
216 /**
217  * ttm_tt_set_placement_caching:
218  *
219  * @ttm A struct ttm_tt the backing pages of which will change caching policy.
220  * @placement: Flag indicating the desired caching policy.
221  *
222  * This function will change caching policy of any default kernel mappings of
223  * the pages backing @ttm. If changing from cached to uncached or
224  * write-combined,
225  * all CPU caches will first be flushed to make sure the data of the pages
226  * hit RAM. This function may be very costly as it involves global TLB
227  * and cache flushes and potential page splitting / combining.
228  */
229 int ttm_tt_set_placement_caching(struct ttm_tt *ttm, uint32_t placement);
230 int ttm_tt_swapout(struct ttm_tt *ttm, struct file *persistent_swap_storage);
231 
232 /**
233  * ttm_tt_populate - allocate pages for a ttm
234  *
235  * @ttm: Pointer to the ttm_tt structure
236  *
237  * Calls the driver method to allocate pages for a ttm
238  */
239 int ttm_tt_populate(struct ttm_tt *ttm, struct ttm_operation_ctx *ctx);
240 
241 /**
242  * ttm_tt_unpopulate - free pages from a ttm
243  *
244  * @ttm: Pointer to the ttm_tt structure
245  *
246  * Calls the driver method to free all pages from a ttm
247  */
248 void ttm_tt_unpopulate(struct ttm_tt *ttm);
249 
250 #if IS_ENABLED(CONFIG_AGP)
251 #include <linux/agp_backend.h>
252 
253 /**
254  * ttm_agp_tt_create
255  *
256  * @bo: Buffer object we allocate the ttm for.
257  * @bridge: The agp bridge this device is sitting on.
258  * @page_flags: Page flags as identified by TTM_PAGE_FLAG_XX flags.
259  *
260  *
261  * Create a TTM backend that uses the indicated AGP bridge as an aperture
262  * for TT memory. This function uses the linux agpgart interface to
263  * bind and unbind memory backing a ttm_tt.
264  */
265 struct ttm_tt *ttm_agp_tt_create(struct ttm_buffer_object *bo,
266 				 struct agp_bridge_data *bridge,
267 				 uint32_t page_flags);
268 int ttm_agp_tt_populate(struct ttm_tt *ttm, struct ttm_operation_ctx *ctx);
269 void ttm_agp_tt_unpopulate(struct ttm_tt *ttm);
270 #endif
271 
272 #endif
273