ardix/include/ardix/dma.h

/* SPDX-License-Identifier: BSD-3-Clause */
/* See the end of this file for copyright, licensing, and warranty information. */

#pragma once

#include <ardix/device.h>
#include <ardix/kent.h>
#include <ardix/types.h>

struct dmabuf {
	struct kent kent;
	size_t len;
	uint8_t data[0];
};

#define kent_to_dmabuf(ptr) container_of(ptr, struct dmabuf, kent)

/**
 * Create a new DMA buffer and its corresponding kent.
 * Use `dmabuf_get` and `dmabuf_put` for refcounting.
 *
 * @param dev: device to create the buffer for
 * @param len: buffer length in bytes
 * @returns a pointer to the buffer, or `NULL` on failure
 */
struct dmabuf *dmabuf_create(struct device *dev, size_t len);

/** Increment a DMA buffer's reference counter. */
void dmabuf_get(struct dmabuf *buf);

/** Decrement a DMA buffer's reference counter. */
void dmabuf_put(struct dmabuf *buf);

/*
 * Copyright (c) 2021 Felix Kopp <sandtler@sandtler.club>
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted
 * provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of
 *    conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
 *    conditions and the following disclaimer in the documentation and/or other materials
 *    provided with the distribution.
 * 3. Neither the name of the copyright holder nor the names of its contributors may be
 *    used to endorse or promote products derived from this software without specific prior
 *    written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
 * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */