linux/include/drm/drm_writeback.h

/* 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.
 */

#ifndef __DRM_WRITEBACK_H__
#define __DRM_WRITEBACK_H__
#include <drm/drm_connector.h>
#include <drm/drm_encoder.h>
#include <linux/workqueue.h>

struct drm_writeback_connector {
	struct drm_connector base;

	/**
	 * @encoder: Internal encoder used by the connector to fulfill
	 * the DRM framework requirements. The users of the
	 * @drm_writeback_connector control the behaviour of the @encoder
	 * by passing the @enc_funcs parameter to drm_writeback_connector_init()
	 * function.
	 */
	struct drm_encoder encoder;

	/**
	 * @pixel_formats_blob_ptr:
	 *
	 * DRM blob property data for the pixel formats list on writeback
	 * connectors
	 * See also drm_writeback_connector_init()
	 */
	struct drm_property_blob *pixel_formats_blob_ptr;

	/** @job_lock: Protects job_queue */
	spinlock_t job_lock;

	/**
	 * @job_queue:
	 *
	 * Holds a list of a connector's writeback jobs; the last item is the
	 * most recent. The first item may be either waiting for the hardware
	 * to begin writing, or currently being written.
	 *
	 * See also: drm_writeback_queue_job() and
	 * drm_writeback_signal_completion()
	 */
	struct list_head job_queue;

	/**
	 * @fence_context:
	 *
	 * timeline context used for fence operations.
	 */
	unsigned int fence_context;
	/**
	 * @fence_lock:
	 *
	 * spinlock to protect the fences in the fence_context.
	 */
	spinlock_t fence_lock;
	/**
	 * @fence_seqno:
	 *
	 * Seqno variable used as monotonic counter for the fences
	 * created on the connector's timeline.
	 */
	unsigned long fence_seqno;
	/**
	 * @timeline_name:
	 *
	 * The name of the connector's fence timeline.
	 */
	char timeline_name[32];
};

struct drm_writeback_job {
	/**
	 * @cleanup_work:
	 *
	 * Used to allow drm_writeback_signal_completion to defer dropping the
	 * framebuffer reference to a workqueue
	 */
	struct work_struct cleanup_work;

	/**
	 * @list_entry:
	 *
	 * List item for the writeback connector's @job_queue
	 */
	struct list_head list_entry;

	/**
	 * @fb:
	 *
	 * Framebuffer to be written to by the writeback connector. Do not set
	 * directly, use drm_atomic_set_writeback_fb_for_connector()
	 */
	struct drm_framebuffer *fb;

	/**
	 * @out_fence:
	 *
	 * Fence which will signal once the writeback has completed
	 */
	struct dma_fence *out_fence;
};

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);

void drm_writeback_queue_job(struct drm_writeback_connector *wb_connector,
			     struct drm_writeback_job *job);

void drm_writeback_cleanup_job(struct drm_writeback_job *job);

void
drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector,
				int status);

struct dma_fence *
drm_writeback_get_out_fence(struct drm_writeback_connector *wb_connector);
#endif