// SPDX-License-Identifier: GPL-2.0/* * (C) COPYRIGHT 2016 ARM Limited. All rights reserved. * Author: Brian Starkey <brian.starkey@arm.com> * * This program is free software and is provided to you under the terms of the * GNU General Public License version 2 as published by the Free Software * Foundation, and any use by you of this program is subject to the terms * of such GNU licence. */ #include <drm/drm_crtc.h>#include <drm/drm_modeset_helper_vtables.h>#include <drm/drm_property.h>#include <drm/drm_writeback.h>#include <drm/drmP.h>#include <linux/dma-fence.h> /** * DOC: overview * * Writeback connectors are used to expose hardware which can write the output * from a CRTC to a memory buffer. They are used and act similarly to other * types of connectors, with some important differences: * * * Writeback connectors don't provide a way to output visually to the user. * * * Writeback connectors are visible to userspace only when the client sets *   DRM_CLIENT_CAP_WRITEBACK_CONNECTORS. * * * Writeback connectors don't have EDID. * * A framebuffer may only be attached to a writeback connector when the * connector is attached to a CRTC. The WRITEBACK_FB_ID property which sets the * framebuffer applies only to a single commit (see below). A framebuffer may * not be attached while the CRTC is off. * * Unlike with planes, when a writeback framebuffer is removed by userspace DRM * makes no attempt to remove it from active use by the connector. This is * because no method is provided to abort a writeback operation, and in any * case making a new commit whilst a writeback is ongoing is undefined (see * WRITEBACK_OUT_FENCE_PTR below). As soon as the current writeback is finished, * the framebuffer will automatically no longer be in active use. As it will * also have already been removed from the framebuffer list, there will be no * way for any userspace application to retrieve a reference to it in the * intervening period. * * Writeback connectors have some additional properties, which userspace * can use to query and control them: * *  "WRITEBACK_FB_ID": *	Write-only object property storing a DRM_MODE_OBJECT_FB: it stores the *	framebuffer to be written by the writeback connector. This property is *	similar to the FB_ID property on planes, but will always read as zero *	and is not preserved across commits. *	Userspace must set this property to an output buffer every time it *	wishes the buffer to get filled. * *  "WRITEBACK_PIXEL_FORMATS": *	Immutable blob property to store the supported pixel formats table. The *	data is an array of u32 DRM_FORMAT_* fourcc values. *	Userspace can use this blob to find out what pixel formats are supported *	by the connector's writeback engine. * *  "WRITEBACK_OUT_FENCE_PTR": *	Userspace can use this property to provide a pointer for the kernel to *	fill with a sync_file file descriptor, which will signal once the *	writeback is finished. The value should be the address of a 32-bit *	signed integer, cast to a u64. *	Userspace should wait for this fence to signal before making another *	commit affecting any of the same CRTCs, Planes or Connectors. *	**Failure to do so will result in undefined behaviour.** *	For this reason it is strongly recommended that all userspace *	applications making use of writeback connectors *always* retrieve an *	out-fence for the commit and use it appropriately. *	From userspace, this property will always read as zero. */ #define fence_to_wb_connector(x) container_of(x->lock, \					      struct drm_writeback_connector, \					      fence_lock) static const char *drm_writeback_fence_get_driver_name(struct dma_fence *fence){	struct drm_writeback_connector *wb_connector =		fence_to_wb_connector(fence); 	return wb_connector->base.dev->driver->name;} static const char *drm_writeback_fence_get_timeline_name(struct dma_fence *fence){	struct drm_writeback_connector *wb_connector =		fence_to_wb_connector(fence); 	return wb_connector->timeline_name;} static bool drm_writeback_fence_enable_signaling(struct dma_fence *fence){	return true;} static const struct dma_fence_ops drm_writeback_fence_ops = {	.get_driver_name = drm_writeback_fence_get_driver_name,	.get_timeline_name = drm_writeback_fence_get_timeline_name,	.enable_signaling = drm_writeback_fence_enable_signaling,	.wait = dma_fence_default_wait,}; static int create_writeback_properties(struct drm_device *dev){	struct drm_property *prop; 	if (!dev->mode_config.writeback_fb_id_property) {		prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC,						  "WRITEBACK_FB_ID",						  DRM_MODE_OBJECT_FB);		if (!prop)			return -ENOMEM;		dev->mode_config.writeback_fb_id_property = prop;	} 	if (!dev->mode_config.writeback_pixel_formats_property) {		prop = drm_property_create(dev, DRM_MODE_PROP_BLOB |					   DRM_MODE_PROP_ATOMIC |					   DRM_MODE_PROP_IMMUTABLE,					   "WRITEBACK_PIXEL_FORMATS", 0);		if (!prop)			return -ENOMEM;		dev->mode_config.writeback_pixel_formats_property = prop;	} 	if (!dev->mode_config.writeback_out_fence_ptr_property) {		prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,						 "WRITEBACK_OUT_FENCE_PTR", 0,						 U64_MAX);		if (!prop)			return -ENOMEM;		dev->mode_config.writeback_out_fence_ptr_property = prop;	} 	return 0;} static const struct drm_encoder_funcs drm_writeback_encoder_funcs = {	.destroy = drm_encoder_cleanup,}; /** * drm_writeback_connector_init - Initialize a writeback connector and its properties * @dev: DRM device * @wb_connector: Writeback connector to initialize * @con_funcs: Connector funcs vtable * @enc_helper_funcs: Encoder helper funcs vtable to be used by the internal encoder * @formats: Array of supported pixel formats for the writeback engine * @n_formats: Length of the formats array * * This function creates the writeback-connector-specific properties if they * have not been already created, initializes the connector as * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property * values. It will also create an internal encoder associated with the * drm_writeback_connector and set it to use the @enc_helper_funcs vtable for * the encoder helper. * * Drivers should always use this function instead of drm_connector_init() to * set up writeback connectors. * * Returns: 0 on success, or a negative error code */int drm_writeback_connector_init(struct drm_device *dev,				 struct drm_writeback_connector *wb_connector,				 const struct drm_connector_funcs *con_funcs,				 const struct drm_encoder_helper_funcs *enc_helper_funcs,				 const u32 *formats, int n_formats){	struct drm_property_blob *blob;	struct drm_connector *connector = &wb_connector->base;	struct drm_mode_config *config = &dev->mode_config;	int ret = create_writeback_properties(dev); 	if (ret != 0)		return ret; 	blob = drm_property_create_blob(dev, n_formats * sizeof(*formats),					formats);	if (IS_ERR(blob))		return PTR_ERR(blob); 	drm_encoder_helper_add(&wb_connector->encoder, enc_helper_funcs);	ret = drm_encoder_init(dev, &wb_connector->encoder,			       &drm_writeback_encoder_funcs,			       DRM_MODE_ENCODER_VIRTUAL, NULL);	if (ret)		goto fail; 	connector->interlace_allowed = 0; 	ret = drm_connector_init(dev, connector, con_funcs,				 DRM_MODE_CONNECTOR_WRITEBACK);	if (ret)		goto connector_fail; 	ret = drm_connector_attach_encoder(connector,						&wb_connector->encoder);	if (ret)		goto attach_fail; 	INIT_LIST_HEAD(&wb_connector->job_queue);	spin_lock_init(&wb_connector->job_lock); 	wb_connector->fence_context = dma_fence_context_alloc(1);	spin_lock_init(&wb_connector->fence_lock);	snprintf(wb_connector->timeline_name,		 sizeof(wb_connector->timeline_name),		 "CONNECTOR:%d-%s", connector->base.id, connector->name); 	drm_object_attach_property(&connector->base,				   config->writeback_out_fence_ptr_property, 0); 	drm_object_attach_property(&connector->base,				   config->writeback_fb_id_property, 0); 	drm_object_attach_property(&connector->base,				   config->writeback_pixel_formats_property,				   blob->base.id);	wb_connector->pixel_formats_blob_ptr = blob; 	return 0; attach_fail:	drm_connector_cleanup(connector);connector_fail:	drm_encoder_cleanup(&wb_connector->encoder);fail:	drm_property_blob_put(blob);	return ret;}EXPORT_SYMBOL(drm_writeback_connector_init); /** * drm_writeback_queue_job - Queue a writeback job for later signalling * @wb_connector: The writeback connector to queue a job on * @job: The job to queue * * This function adds a job to the job_queue for a writeback connector. It * should be considered to take ownership of the writeback job, and so any other * references to the job must be cleared after calling this function. * * Drivers must ensure that for a given writeback connector, jobs are queued in * exactly the same order as they will be completed by the hardware (and * signaled via drm_writeback_signal_completion). * * For every call to drm_writeback_queue_job() there must be exactly one call to * drm_writeback_signal_completion() * * See also: drm_writeback_signal_completion() */void drm_writeback_queue_job(struct drm_writeback_connector *wb_connector,			     struct drm_writeback_job *job){	unsigned long flags; 	spin_lock_irqsave(&wb_connector->job_lock, flags);	list_add_tail(&job->list_entry, &wb_connector->job_queue);	spin_unlock_irqrestore(&wb_connector->job_lock, flags);}EXPORT_SYMBOL(drm_writeback_queue_job); /* * @cleanup_work: deferred cleanup of a writeback job * * The job cannot be cleaned up directly in drm_writeback_signal_completion, * because it may be called in interrupt context. Dropping the framebuffer * reference can sleep, and so the cleanup is deferred to a workqueue. */static void cleanup_work(struct work_struct *work){	struct drm_writeback_job *job = container_of(work,						     struct drm_writeback_job,						     cleanup_work);	drm_framebuffer_put(job->fb);	kfree(job);}  /** * drm_writeback_signal_completion - Signal the completion of a writeback job * @wb_connector: The writeback connector whose job is complete * @status: Status code to set in the writeback out_fence (0 for success) * * Drivers should call this to signal the completion of a previously queued * writeback job. It should be called as soon as possible after the hardware * has finished writing, and may be called from interrupt context. * It is the driver's responsibility to ensure that for a given connector, the * hardware completes writeback jobs in the same order as they are queued. * * Unless the driver is holding its own reference to the framebuffer, it must * not be accessed after calling this function. * * See also: drm_writeback_queue_job() */voiddrm_writeback_signal_completion(struct drm_writeback_connector *wb_connector,				int status){	unsigned long flags;	struct drm_writeback_job *job; 	spin_lock_irqsave(&wb_connector->job_lock, flags);	job = list_first_entry_or_null(&wb_connector->job_queue,				       struct drm_writeback_job,				       list_entry);	if (job) {		list_del(&job->list_entry);		if (job->out_fence) {			if (status)				dma_fence_set_error(job->out_fence, status);			dma_fence_signal(job->out_fence);			dma_fence_put(job->out_fence);		}	}	spin_unlock_irqrestore(&wb_connector->job_lock, flags); 	if (WARN_ON(!job))		return; 	INIT_WORK(&job->cleanup_work, cleanup_work);	queue_work(system_long_wq, &job->cleanup_work);}EXPORT_SYMBOL(drm_writeback_signal_completion); struct dma_fence *drm_writeback_get_out_fence(struct drm_writeback_connector *wb_connector){	struct dma_fence *fence; 	if (WARN_ON(wb_connector->base.connector_type !=		    DRM_MODE_CONNECTOR_WRITEBACK))		return NULL; 	fence = kzalloc(sizeof(*fence), GFP_KERNEL);	if (!fence)		return NULL; 	dma_fence_init(fence, &drm_writeback_fence_ops,		       &wb_connector->fence_lock, wb_connector->fence_context,		       ++wb_connector->fence_seqno); 	return fence;}EXPORT_SYMBOL(drm_writeback_get_out_fence);