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935774cd BS |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * (C) COPYRIGHT 2016 ARM Limited. All rights reserved. | |
4 | * Author: Brian Starkey <brian.starkey@arm.com> | |
5 | * | |
6 | * This program is free software and is provided to you under the terms of the | |
7 | * GNU General Public License version 2 as published by the Free Software | |
8 | * Foundation, and any use by you of this program is subject to the terms | |
9 | * of such GNU licence. | |
10 | */ | |
11 | ||
0500c04e SR |
12 | #include <linux/dma-fence.h> |
13 | ||
935774cd | 14 | #include <drm/drm_crtc.h> |
0500c04e SR |
15 | #include <drm/drm_device.h> |
16 | #include <drm/drm_drv.h> | |
720cf96d | 17 | #include <drm/drm_framebuffer.h> |
935774cd BS |
18 | #include <drm/drm_modeset_helper_vtables.h> |
19 | #include <drm/drm_property.h> | |
20 | #include <drm/drm_writeback.h> | |
935774cd BS |
21 | |
22 | /** | |
23 | * DOC: overview | |
24 | * | |
25 | * Writeback connectors are used to expose hardware which can write the output | |
26 | * from a CRTC to a memory buffer. They are used and act similarly to other | |
27 | * types of connectors, with some important differences: | |
73915b2b BB |
28 | * |
29 | * * Writeback connectors don't provide a way to output visually to the user. | |
30 | * | |
71a5cb3e AG |
31 | * * Writeback connectors are visible to userspace only when the client sets |
32 | * DRM_CLIENT_CAP_WRITEBACK_CONNECTORS. | |
73915b2b BB |
33 | * |
34 | * * Writeback connectors don't have EDID. | |
935774cd BS |
35 | * |
36 | * A framebuffer may only be attached to a writeback connector when the | |
37 | * connector is attached to a CRTC. The WRITEBACK_FB_ID property which sets the | |
38 | * framebuffer applies only to a single commit (see below). A framebuffer may | |
39 | * not be attached while the CRTC is off. | |
40 | * | |
b13cc8dd BS |
41 | * Unlike with planes, when a writeback framebuffer is removed by userspace DRM |
42 | * makes no attempt to remove it from active use by the connector. This is | |
43 | * because no method is provided to abort a writeback operation, and in any | |
44 | * case making a new commit whilst a writeback is ongoing is undefined (see | |
45 | * WRITEBACK_OUT_FENCE_PTR below). As soon as the current writeback is finished, | |
46 | * the framebuffer will automatically no longer be in active use. As it will | |
47 | * also have already been removed from the framebuffer list, there will be no | |
48 | * way for any userspace application to retrieve a reference to it in the | |
49 | * intervening period. | |
50 | * | |
935774cd BS |
51 | * Writeback connectors have some additional properties, which userspace |
52 | * can use to query and control them: | |
53 | * | |
54 | * "WRITEBACK_FB_ID": | |
55 | * Write-only object property storing a DRM_MODE_OBJECT_FB: it stores the | |
56 | * framebuffer to be written by the writeback connector. This property is | |
57 | * similar to the FB_ID property on planes, but will always read as zero | |
58 | * and is not preserved across commits. | |
59 | * Userspace must set this property to an output buffer every time it | |
60 | * wishes the buffer to get filled. | |
61 | * | |
62 | * "WRITEBACK_PIXEL_FORMATS": | |
63 | * Immutable blob property to store the supported pixel formats table. The | |
64 | * data is an array of u32 DRM_FORMAT_* fourcc values. | |
65 | * Userspace can use this blob to find out what pixel formats are supported | |
66 | * by the connector's writeback engine. | |
b13cc8dd BS |
67 | * |
68 | * "WRITEBACK_OUT_FENCE_PTR": | |
69 | * Userspace can use this property to provide a pointer for the kernel to | |
70 | * fill with a sync_file file descriptor, which will signal once the | |
71 | * writeback is finished. The value should be the address of a 32-bit | |
72 | * signed integer, cast to a u64. | |
73 | * Userspace should wait for this fence to signal before making another | |
74 | * commit affecting any of the same CRTCs, Planes or Connectors. | |
75 | * **Failure to do so will result in undefined behaviour.** | |
76 | * For this reason it is strongly recommended that all userspace | |
77 | * applications making use of writeback connectors *always* retrieve an | |
78 | * out-fence for the commit and use it appropriately. | |
79 | * From userspace, this property will always read as zero. | |
935774cd BS |
80 | */ |
81 | ||
b13cc8dd BS |
82 | #define fence_to_wb_connector(x) container_of(x->lock, \ |
83 | struct drm_writeback_connector, \ | |
84 | fence_lock) | |
85 | ||
86 | static const char *drm_writeback_fence_get_driver_name(struct dma_fence *fence) | |
87 | { | |
88 | struct drm_writeback_connector *wb_connector = | |
89 | fence_to_wb_connector(fence); | |
90 | ||
91 | return wb_connector->base.dev->driver->name; | |
92 | } | |
93 | ||
94 | static const char * | |
95 | drm_writeback_fence_get_timeline_name(struct dma_fence *fence) | |
96 | { | |
97 | struct drm_writeback_connector *wb_connector = | |
98 | fence_to_wb_connector(fence); | |
99 | ||
100 | return wb_connector->timeline_name; | |
101 | } | |
102 | ||
103 | static bool drm_writeback_fence_enable_signaling(struct dma_fence *fence) | |
104 | { | |
105 | return true; | |
106 | } | |
107 | ||
108 | static const struct dma_fence_ops drm_writeback_fence_ops = { | |
109 | .get_driver_name = drm_writeback_fence_get_driver_name, | |
110 | .get_timeline_name = drm_writeback_fence_get_timeline_name, | |
111 | .enable_signaling = drm_writeback_fence_enable_signaling, | |
b13cc8dd BS |
112 | }; |
113 | ||
935774cd BS |
114 | static int create_writeback_properties(struct drm_device *dev) |
115 | { | |
116 | struct drm_property *prop; | |
117 | ||
118 | if (!dev->mode_config.writeback_fb_id_property) { | |
119 | prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC, | |
120 | "WRITEBACK_FB_ID", | |
121 | DRM_MODE_OBJECT_FB); | |
122 | if (!prop) | |
123 | return -ENOMEM; | |
124 | dev->mode_config.writeback_fb_id_property = prop; | |
125 | } | |
126 | ||
127 | if (!dev->mode_config.writeback_pixel_formats_property) { | |
128 | prop = drm_property_create(dev, DRM_MODE_PROP_BLOB | | |
129 | DRM_MODE_PROP_ATOMIC | | |
130 | DRM_MODE_PROP_IMMUTABLE, | |
131 | "WRITEBACK_PIXEL_FORMATS", 0); | |
132 | if (!prop) | |
133 | return -ENOMEM; | |
134 | dev->mode_config.writeback_pixel_formats_property = prop; | |
135 | } | |
136 | ||
b13cc8dd BS |
137 | if (!dev->mode_config.writeback_out_fence_ptr_property) { |
138 | prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC, | |
139 | "WRITEBACK_OUT_FENCE_PTR", 0, | |
140 | U64_MAX); | |
141 | if (!prop) | |
142 | return -ENOMEM; | |
143 | dev->mode_config.writeback_out_fence_ptr_property = prop; | |
144 | } | |
145 | ||
935774cd BS |
146 | return 0; |
147 | } | |
148 | ||
149 | static const struct drm_encoder_funcs drm_writeback_encoder_funcs = { | |
150 | .destroy = drm_encoder_cleanup, | |
151 | }; | |
152 | ||
153 | /** | |
154 | * drm_writeback_connector_init - Initialize a writeback connector and its properties | |
155 | * @dev: DRM device | |
156 | * @wb_connector: Writeback connector to initialize | |
157 | * @con_funcs: Connector funcs vtable | |
158 | * @enc_helper_funcs: Encoder helper funcs vtable to be used by the internal encoder | |
159 | * @formats: Array of supported pixel formats for the writeback engine | |
160 | * @n_formats: Length of the formats array | |
57b8280a | 161 | * @possible_crtcs: possible crtcs for the internal writeback encoder |
935774cd BS |
162 | * |
163 | * This function creates the writeback-connector-specific properties if they | |
164 | * have not been already created, initializes the connector as | |
165 | * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property | |
166 | * values. It will also create an internal encoder associated with the | |
167 | * drm_writeback_connector and set it to use the @enc_helper_funcs vtable for | |
168 | * the encoder helper. | |
169 | * | |
170 | * Drivers should always use this function instead of drm_connector_init() to | |
171 | * set up writeback connectors. | |
172 | * | |
173 | * Returns: 0 on success, or a negative error code | |
174 | */ | |
175 | int drm_writeback_connector_init(struct drm_device *dev, | |
176 | struct drm_writeback_connector *wb_connector, | |
177 | const struct drm_connector_funcs *con_funcs, | |
178 | const struct drm_encoder_helper_funcs *enc_helper_funcs, | |
57b8280a AK |
179 | const u32 *formats, int n_formats, |
180 | u32 possible_crtcs) | |
7933aecf AK |
181 | { |
182 | int ret = 0; | |
183 | ||
184 | drm_encoder_helper_add(&wb_connector->encoder, enc_helper_funcs); | |
185 | ||
186 | wb_connector->encoder.possible_crtcs = possible_crtcs; | |
187 | ||
188 | ret = drm_encoder_init(dev, &wb_connector->encoder, | |
189 | &drm_writeback_encoder_funcs, | |
190 | DRM_MODE_ENCODER_VIRTUAL, NULL); | |
191 | if (ret) | |
192 | return ret; | |
193 | ||
194 | ret = drm_writeback_connector_init_with_encoder(dev, wb_connector, &wb_connector->encoder, | |
195 | con_funcs, formats, n_formats); | |
196 | ||
197 | if (ret) | |
198 | drm_encoder_cleanup(&wb_connector->encoder); | |
199 | ||
200 | return ret; | |
201 | } | |
202 | EXPORT_SYMBOL(drm_writeback_connector_init); | |
203 | ||
204 | /** | |
205 | * drm_writeback_connector_init_with_encoder - Initialize a writeback connector with | |
206 | * a custom encoder | |
207 | * | |
208 | * @dev: DRM device | |
209 | * @wb_connector: Writeback connector to initialize | |
210 | * @enc: handle to the already initialized drm encoder | |
211 | * @con_funcs: Connector funcs vtable | |
212 | * @formats: Array of supported pixel formats for the writeback engine | |
213 | * @n_formats: Length of the formats array | |
214 | * | |
215 | * This function creates the writeback-connector-specific properties if they | |
216 | * have not been already created, initializes the connector as | |
217 | * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property | |
218 | * values. | |
219 | * | |
220 | * This function assumes that the drm_writeback_connector's encoder has already been | |
221 | * created and initialized before invoking this function. | |
222 | * | |
223 | * In addition, this function also assumes that callers of this API will manage | |
224 | * assigning the encoder helper functions, possible_crtcs and any other encoder | |
225 | * specific operation. | |
226 | * | |
227 | * Drivers should always use this function instead of drm_connector_init() to | |
228 | * set up writeback connectors if they want to manage themselves the lifetime of the | |
229 | * associated encoder. | |
230 | * | |
231 | * Returns: 0 on success, or a negative error code | |
232 | */ | |
233 | int drm_writeback_connector_init_with_encoder(struct drm_device *dev, | |
234 | struct drm_writeback_connector *wb_connector, struct drm_encoder *enc, | |
235 | const struct drm_connector_funcs *con_funcs, const u32 *formats, | |
236 | int n_formats) | |
935774cd BS |
237 | { |
238 | struct drm_property_blob *blob; | |
239 | struct drm_connector *connector = &wb_connector->base; | |
240 | struct drm_mode_config *config = &dev->mode_config; | |
241 | int ret = create_writeback_properties(dev); | |
242 | ||
243 | if (ret != 0) | |
244 | return ret; | |
245 | ||
246 | blob = drm_property_create_blob(dev, n_formats * sizeof(*formats), | |
247 | formats); | |
248 | if (IS_ERR(blob)) | |
249 | return PTR_ERR(blob); | |
250 | ||
935774cd BS |
251 | |
252 | connector->interlace_allowed = 0; | |
253 | ||
254 | ret = drm_connector_init(dev, connector, con_funcs, | |
255 | DRM_MODE_CONNECTOR_WRITEBACK); | |
256 | if (ret) | |
257 | goto connector_fail; | |
258 | ||
7933aecf | 259 | ret = drm_connector_attach_encoder(connector, enc); |
935774cd BS |
260 | if (ret) |
261 | goto attach_fail; | |
262 | ||
263 | INIT_LIST_HEAD(&wb_connector->job_queue); | |
264 | spin_lock_init(&wb_connector->job_lock); | |
265 | ||
b13cc8dd BS |
266 | wb_connector->fence_context = dma_fence_context_alloc(1); |
267 | spin_lock_init(&wb_connector->fence_lock); | |
268 | snprintf(wb_connector->timeline_name, | |
269 | sizeof(wb_connector->timeline_name), | |
270 | "CONNECTOR:%d-%s", connector->base.id, connector->name); | |
271 | ||
272 | drm_object_attach_property(&connector->base, | |
273 | config->writeback_out_fence_ptr_property, 0); | |
274 | ||
935774cd BS |
275 | drm_object_attach_property(&connector->base, |
276 | config->writeback_fb_id_property, 0); | |
277 | ||
278 | drm_object_attach_property(&connector->base, | |
279 | config->writeback_pixel_formats_property, | |
280 | blob->base.id); | |
281 | wb_connector->pixel_formats_blob_ptr = blob; | |
282 | ||
283 | return 0; | |
284 | ||
285 | attach_fail: | |
286 | drm_connector_cleanup(connector); | |
287 | connector_fail: | |
935774cd BS |
288 | drm_property_blob_put(blob); |
289 | return ret; | |
290 | } | |
7933aecf | 291 | EXPORT_SYMBOL(drm_writeback_connector_init_with_encoder); |
935774cd | 292 | |
9d2230dc LP |
293 | int drm_writeback_set_fb(struct drm_connector_state *conn_state, |
294 | struct drm_framebuffer *fb) | |
295 | { | |
296 | WARN_ON(conn_state->connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK); | |
297 | ||
298 | if (!conn_state->writeback_job) { | |
299 | conn_state->writeback_job = | |
300 | kzalloc(sizeof(*conn_state->writeback_job), GFP_KERNEL); | |
301 | if (!conn_state->writeback_job) | |
302 | return -ENOMEM; | |
303 | ||
304 | conn_state->writeback_job->connector = | |
305 | drm_connector_to_writeback(conn_state->connector); | |
306 | } | |
307 | ||
308 | drm_framebuffer_assign(&conn_state->writeback_job->fb, fb); | |
309 | return 0; | |
310 | } | |
311 | ||
312 | int drm_writeback_prepare_job(struct drm_writeback_job *job) | |
313 | { | |
314 | struct drm_writeback_connector *connector = job->connector; | |
315 | const struct drm_connector_helper_funcs *funcs = | |
316 | connector->base.helper_private; | |
317 | int ret; | |
318 | ||
319 | if (funcs->prepare_writeback_job) { | |
320 | ret = funcs->prepare_writeback_job(connector, job); | |
321 | if (ret < 0) | |
322 | return ret; | |
323 | } | |
324 | ||
325 | job->prepared = true; | |
326 | return 0; | |
327 | } | |
328 | EXPORT_SYMBOL(drm_writeback_prepare_job); | |
329 | ||
935774cd BS |
330 | /** |
331 | * drm_writeback_queue_job - Queue a writeback job for later signalling | |
332 | * @wb_connector: The writeback connector to queue a job on | |
97eb9eae | 333 | * @conn_state: The connector state containing the job to queue |
935774cd | 334 | * |
97eb9eae LP |
335 | * This function adds the job contained in @conn_state to the job_queue for a |
336 | * writeback connector. It takes ownership of the writeback job and sets the | |
337 | * @conn_state->writeback_job to NULL, and so no access to the job may be | |
338 | * performed by the caller after this function returns. | |
935774cd BS |
339 | * |
340 | * Drivers must ensure that for a given writeback connector, jobs are queued in | |
341 | * exactly the same order as they will be completed by the hardware (and | |
342 | * signaled via drm_writeback_signal_completion). | |
343 | * | |
344 | * For every call to drm_writeback_queue_job() there must be exactly one call to | |
345 | * drm_writeback_signal_completion() | |
346 | * | |
347 | * See also: drm_writeback_signal_completion() | |
348 | */ | |
349 | void drm_writeback_queue_job(struct drm_writeback_connector *wb_connector, | |
97eb9eae | 350 | struct drm_connector_state *conn_state) |
935774cd | 351 | { |
97eb9eae | 352 | struct drm_writeback_job *job; |
935774cd BS |
353 | unsigned long flags; |
354 | ||
97eb9eae LP |
355 | job = conn_state->writeback_job; |
356 | conn_state->writeback_job = NULL; | |
357 | ||
935774cd BS |
358 | spin_lock_irqsave(&wb_connector->job_lock, flags); |
359 | list_add_tail(&job->list_entry, &wb_connector->job_queue); | |
360 | spin_unlock_irqrestore(&wb_connector->job_lock, flags); | |
361 | } | |
362 | EXPORT_SYMBOL(drm_writeback_queue_job); | |
363 | ||
e482ae9b LP |
364 | void drm_writeback_cleanup_job(struct drm_writeback_job *job) |
365 | { | |
9d2230dc LP |
366 | struct drm_writeback_connector *connector = job->connector; |
367 | const struct drm_connector_helper_funcs *funcs = | |
368 | connector->base.helper_private; | |
369 | ||
370 | if (job->prepared && funcs->cleanup_writeback_job) | |
371 | funcs->cleanup_writeback_job(connector, job); | |
372 | ||
e482ae9b LP |
373 | if (job->fb) |
374 | drm_framebuffer_put(job->fb); | |
375 | ||
b1066a12 LLATC |
376 | if (job->out_fence) |
377 | dma_fence_put(job->out_fence); | |
378 | ||
e482ae9b LP |
379 | kfree(job); |
380 | } | |
381 | EXPORT_SYMBOL(drm_writeback_cleanup_job); | |
382 | ||
935774cd BS |
383 | /* |
384 | * @cleanup_work: deferred cleanup of a writeback job | |
385 | * | |
386 | * The job cannot be cleaned up directly in drm_writeback_signal_completion, | |
387 | * because it may be called in interrupt context. Dropping the framebuffer | |
388 | * reference can sleep, and so the cleanup is deferred to a workqueue. | |
389 | */ | |
390 | static void cleanup_work(struct work_struct *work) | |
391 | { | |
392 | struct drm_writeback_job *job = container_of(work, | |
393 | struct drm_writeback_job, | |
394 | cleanup_work); | |
935774cd | 395 | |
e482ae9b LP |
396 | drm_writeback_cleanup_job(job); |
397 | } | |
935774cd BS |
398 | |
399 | /** | |
400 | * drm_writeback_signal_completion - Signal the completion of a writeback job | |
401 | * @wb_connector: The writeback connector whose job is complete | |
b13cc8dd | 402 | * @status: Status code to set in the writeback out_fence (0 for success) |
935774cd BS |
403 | * |
404 | * Drivers should call this to signal the completion of a previously queued | |
405 | * writeback job. It should be called as soon as possible after the hardware | |
406 | * has finished writing, and may be called from interrupt context. | |
407 | * It is the driver's responsibility to ensure that for a given connector, the | |
408 | * hardware completes writeback jobs in the same order as they are queued. | |
409 | * | |
410 | * Unless the driver is holding its own reference to the framebuffer, it must | |
411 | * not be accessed after calling this function. | |
412 | * | |
413 | * See also: drm_writeback_queue_job() | |
414 | */ | |
415 | void | |
b13cc8dd BS |
416 | drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector, |
417 | int status) | |
935774cd BS |
418 | { |
419 | unsigned long flags; | |
420 | struct drm_writeback_job *job; | |
b1066a12 | 421 | struct dma_fence *out_fence; |
935774cd BS |
422 | |
423 | spin_lock_irqsave(&wb_connector->job_lock, flags); | |
424 | job = list_first_entry_or_null(&wb_connector->job_queue, | |
425 | struct drm_writeback_job, | |
426 | list_entry); | |
b1066a12 | 427 | if (job) |
935774cd | 428 | list_del(&job->list_entry); |
b1066a12 | 429 | |
935774cd BS |
430 | spin_unlock_irqrestore(&wb_connector->job_lock, flags); |
431 | ||
432 | if (WARN_ON(!job)) | |
433 | return; | |
434 | ||
b1066a12 LLATC |
435 | out_fence = job->out_fence; |
436 | if (out_fence) { | |
437 | if (status) | |
438 | dma_fence_set_error(out_fence, status); | |
439 | dma_fence_signal(out_fence); | |
440 | dma_fence_put(out_fence); | |
441 | job->out_fence = NULL; | |
442 | } | |
443 | ||
935774cd BS |
444 | INIT_WORK(&job->cleanup_work, cleanup_work); |
445 | queue_work(system_long_wq, &job->cleanup_work); | |
446 | } | |
447 | EXPORT_SYMBOL(drm_writeback_signal_completion); | |
b13cc8dd BS |
448 | |
449 | struct dma_fence * | |
450 | drm_writeback_get_out_fence(struct drm_writeback_connector *wb_connector) | |
451 | { | |
452 | struct dma_fence *fence; | |
453 | ||
454 | if (WARN_ON(wb_connector->base.connector_type != | |
455 | DRM_MODE_CONNECTOR_WRITEBACK)) | |
456 | return NULL; | |
457 | ||
458 | fence = kzalloc(sizeof(*fence), GFP_KERNEL); | |
459 | if (!fence) | |
460 | return NULL; | |
461 | ||
462 | dma_fence_init(fence, &drm_writeback_fence_ops, | |
463 | &wb_connector->fence_lock, wb_connector->fence_context, | |
464 | ++wb_connector->fence_seqno); | |
465 | ||
466 | return fence; | |
467 | } | |
468 | EXPORT_SYMBOL(drm_writeback_get_out_fence); |