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1// SPDX-License-Identifier: GPL-2.02/*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 the7 * GNU General Public License version 2 as published by the Free Software8 * Foundation, and any use by you of this program is subject to the terms9 * of such GNU licence.10 */11 12#include <linux/dma-fence.h>13 14#include <drm/drm_crtc.h>15#include <drm/drm_device.h>16#include <drm/drm_drv.h>17#include <drm/drm_framebuffer.h>18#include <drm/drm_modeset_helper_vtables.h>19#include <drm/drm_property.h>20#include <drm/drm_writeback.h>21 22/**23 * DOC: overview24 *25 * Writeback connectors are used to expose hardware which can write the output26 * from a CRTC to a memory buffer. They are used and act similarly to other27 * types of connectors, with some important differences:28 *29 * * Writeback connectors don't provide a way to output visually to the user.30 *31 * * Writeback connectors are visible to userspace only when the client sets32 * DRM_CLIENT_CAP_WRITEBACK_CONNECTORS.33 *34 * * Writeback connectors don't have EDID.35 *36 * A framebuffer may only be attached to a writeback connector when the37 * connector is attached to a CRTC. The WRITEBACK_FB_ID property which sets the38 * framebuffer applies only to a single commit (see below). A framebuffer may39 * not be attached while the CRTC is off.40 *41 * Unlike with planes, when a writeback framebuffer is removed by userspace DRM42 * makes no attempt to remove it from active use by the connector. This is43 * because no method is provided to abort a writeback operation, and in any44 * case making a new commit whilst a writeback is ongoing is undefined (see45 * 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 will47 * also have already been removed from the framebuffer list, there will be no48 * way for any userspace application to retrieve a reference to it in the49 * intervening period.50 *51 * Writeback connectors have some additional properties, which userspace52 * 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 the56 * framebuffer to be written by the writeback connector. This property is57 * similar to the FB_ID property on planes, but will always read as zero58 * and is not preserved across commits.59 * Userspace must set this property to an output buffer every time it60 * wishes the buffer to get filled.61 *62 * "WRITEBACK_PIXEL_FORMATS":63 * Immutable blob property to store the supported pixel formats table. The64 * data is an array of u32 DRM_FORMAT_* fourcc values.65 * Userspace can use this blob to find out what pixel formats are supported66 * by the connector's writeback engine.67 *68 * "WRITEBACK_OUT_FENCE_PTR":69 * Userspace can use this property to provide a pointer for the kernel to70 * fill with a sync_file file descriptor, which will signal once the71 * writeback is finished. The value should be the address of a 32-bit72 * signed integer, cast to a u64.73 * Userspace should wait for this fence to signal before making another74 * 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 userspace77 * applications making use of writeback connectors *always* retrieve an78 * out-fence for the commit and use it appropriately.79 * From userspace, this property will always read as zero.80 */81 82#define fence_to_wb_connector(x) container_of(x->lock, \83 struct drm_writeback_connector, \84 fence_lock)85 86static 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 94static const char *95drm_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 103static bool drm_writeback_fence_enable_signaling(struct dma_fence *fence)104{105 return true;106}107 108static 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,112};113 114static 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 }136 137 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 }145 146 return 0;147}148 149static 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 properties155 * @dev: DRM device156 * @wb_connector: Writeback connector to initialize157 * @con_funcs: Connector funcs vtable158 * @enc_helper_funcs: Encoder helper funcs vtable to be used by the internal encoder159 * @formats: Array of supported pixel formats for the writeback engine160 * @n_formats: Length of the formats array161 * @possible_crtcs: possible crtcs for the internal writeback encoder162 *163 * This function creates the writeback-connector-specific properties if they164 * have not been already created, initializes the connector as165 * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property166 * values. It will also create an internal encoder associated with the167 * drm_writeback_connector and set it to use the @enc_helper_funcs vtable for168 * the encoder helper.169 *170 * Drivers should always use this function instead of drm_connector_init() to171 * set up writeback connectors.172 *173 * Returns: 0 on success, or a negative error code174 */175int 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,179 const u32 *formats, int n_formats,180 u32 possible_crtcs)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}202EXPORT_SYMBOL(drm_writeback_connector_init);203 204/**205 * drm_writeback_connector_init_with_encoder - Initialize a writeback connector with206 * a custom encoder207 *208 * @dev: DRM device209 * @wb_connector: Writeback connector to initialize210 * @enc: handle to the already initialized drm encoder211 * @con_funcs: Connector funcs vtable212 * @formats: Array of supported pixel formats for the writeback engine213 * @n_formats: Length of the formats array214 *215 * This function creates the writeback-connector-specific properties if they216 * have not been already created, initializes the connector as217 * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property218 * values.219 *220 * This function assumes that the drm_writeback_connector's encoder has already been221 * created and initialized before invoking this function.222 *223 * In addition, this function also assumes that callers of this API will manage224 * assigning the encoder helper functions, possible_crtcs and any other encoder225 * specific operation.226 *227 * Drivers should always use this function instead of drm_connector_init() to228 * set up writeback connectors if they want to manage themselves the lifetime of the229 * associated encoder.230 *231 * Returns: 0 on success, or a negative error code232 */233int 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)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);250 251 252 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;258 259 ret = drm_connector_attach_encoder(connector, enc);260 if (ret)261 goto attach_fail;262 263 INIT_LIST_HEAD(&wb_connector->job_queue);264 spin_lock_init(&wb_connector->job_lock);265 266 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);274 275 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 285attach_fail:286 drm_connector_cleanup(connector);287connector_fail:288 drm_property_blob_put(blob);289 return ret;290}291EXPORT_SYMBOL(drm_writeback_connector_init_with_encoder);292 293int 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 312int 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}328EXPORT_SYMBOL(drm_writeback_prepare_job);329 330/**331 * drm_writeback_queue_job - Queue a writeback job for later signalling332 * @wb_connector: The writeback connector to queue a job on333 * @conn_state: The connector state containing the job to queue334 *335 * This function adds the job contained in @conn_state to the job_queue for a336 * writeback connector. It takes ownership of the writeback job and sets the337 * @conn_state->writeback_job to NULL, and so no access to the job may be338 * performed by the caller after this function returns.339 *340 * Drivers must ensure that for a given writeback connector, jobs are queued in341 * exactly the same order as they will be completed by the hardware (and342 * signaled via drm_writeback_signal_completion).343 *344 * For every call to drm_writeback_queue_job() there must be exactly one call to345 * drm_writeback_signal_completion()346 *347 * See also: drm_writeback_signal_completion()348 */349void drm_writeback_queue_job(struct drm_writeback_connector *wb_connector,350 struct drm_connector_state *conn_state)351{352 struct drm_writeback_job *job;353 unsigned long flags;354 355 job = conn_state->writeback_job;356 conn_state->writeback_job = NULL;357 358 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}362EXPORT_SYMBOL(drm_writeback_queue_job);363 364void drm_writeback_cleanup_job(struct drm_writeback_job *job)365{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);372 373 if (job->fb)374 drm_framebuffer_put(job->fb);375 376 if (job->out_fence)377 dma_fence_put(job->out_fence);378 379 kfree(job);380}381EXPORT_SYMBOL(drm_writeback_cleanup_job);382 383/*384 * @cleanup_work: deferred cleanup of a writeback job385 *386 * The job cannot be cleaned up directly in drm_writeback_signal_completion,387 * because it may be called in interrupt context. Dropping the framebuffer388 * reference can sleep, and so the cleanup is deferred to a workqueue.389 */390static 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);395 396 drm_writeback_cleanup_job(job);397}398 399/**400 * drm_writeback_signal_completion - Signal the completion of a writeback job401 * @wb_connector: The writeback connector whose job is complete402 * @status: Status code to set in the writeback out_fence (0 for success)403 *404 * Drivers should call this to signal the completion of a previously queued405 * writeback job. It should be called as soon as possible after the hardware406 * has finished writing, and may be called from interrupt context.407 * It is the driver's responsibility to ensure that for a given connector, the408 * 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 must411 * not be accessed after calling this function.412 *413 * See also: drm_writeback_queue_job()414 */415void416drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector,417 int status)418{419 unsigned long flags;420 struct drm_writeback_job *job;421 struct dma_fence *out_fence;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);427 if (job)428 list_del(&job->list_entry);429 430 spin_unlock_irqrestore(&wb_connector->job_lock, flags);431 432 if (WARN_ON(!job))433 return;434 435 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 }443 444 INIT_WORK(&job->cleanup_work, cleanup_work);445 queue_work(system_long_wq, &job->cleanup_work);446}447EXPORT_SYMBOL(drm_writeback_signal_completion);448 449struct dma_fence *450drm_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}468EXPORT_SYMBOL(drm_writeback_get_out_fence);469