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Filename : dvb_vb2.h
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/*
 * SPDX-License-Identifier: GPL-2.0
 *
 * dvb-vb2.h - DVB driver helper framework for streaming I/O
 *
 * Copyright (C) 2015 Samsung Electronics
 *
 * Author: jh1009.sung@samsung.com
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation.
 */

#ifndef _DVB_VB2_H
#define _DVB_VB2_H

#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/dvb/dmx.h>
#include <media/videobuf2-core.h>
#include <media/videobuf2-dma-contig.h>
#include <media/videobuf2-vmalloc.h>

/**
 * enum dvb_buf_type - types of Digital TV memory-mapped buffers
 *
 * @DVB_BUF_TYPE_CAPTURE: buffer is filled by the Kernel,
 *			  with a received Digital TV stream
 */
enum dvb_buf_type {
	DVB_BUF_TYPE_CAPTURE        = 1,
};

/**
 * enum dvb_vb2_states - states to control VB2 state machine
 * @DVB_VB2_STATE_NONE:
 *	VB2 engine not initialized yet, init failed or VB2 was released.
 * @DVB_VB2_STATE_INIT:
 *	VB2 engine initialized.
 * @DVB_VB2_STATE_REQBUFS:
 *	Buffers were requested
 * @DVB_VB2_STATE_STREAMON:
 *	VB2 is streaming. Callers should not check it directly. Instead,
 *	they should use dvb_vb2_is_streaming().
 *
 * Note:
 *
 * Callers should not touch at the state machine directly. This
 * is handled inside dvb_vb2.c.
 */
enum dvb_vb2_states {
	DVB_VB2_STATE_NONE	= 0x0,
	DVB_VB2_STATE_INIT	= 0x1,
	DVB_VB2_STATE_REQBUFS	= 0x2,
	DVB_VB2_STATE_STREAMON	= 0x4,
};

#define DVB_VB2_NAME_MAX (20)

/**
 * struct dvb_buffer - video buffer information for v4l2.
 *
 * @vb:		embedded struct &vb2_buffer.
 * @list:	list of &struct dvb_buffer.
 */
struct dvb_buffer {
	struct vb2_buffer	vb;
	struct list_head	list;
};

/**
 * struct dvb_vb2_ctx - control struct for VB2 handler
 * @vb_q:	pointer to &struct vb2_queue with videobuf2 queue.
 * @mutex:	mutex to serialize vb2 operations. Used by
 *		vb2 core %wait_prepare and %wait_finish operations.
 * @slock:	spin lock used to protect buffer filling at dvb_vb2.c.
 * @dvb_q:	List of buffers that are not filled yet.
 * @buf:	Pointer to the buffer that are currently being filled.
 * @offset:	index to the next position at the @buf to be filled.
 * @remain:	How many bytes are left to be filled at @buf.
 * @state:	bitmask of buffer states as defined by &enum dvb_vb2_states.
 * @buf_siz:	size of each VB2 buffer.
 * @buf_cnt:	number of VB2 buffers.
 * @nonblocking:
 *		If different than zero, device is operating on non-blocking
 *		mode.
 * @flags:	buffer flags as defined by &enum dmx_buffer_flags.
 *		Filled only at &DMX_DQBUF. &DMX_QBUF should zero this field.
 * @count:	monotonic counter for filled buffers. Helps to identify
 *		data stream loses. Filled only at &DMX_DQBUF. &DMX_QBUF should
 *		zero this field.
 *
 * @name:	name of the device type. Currently, it can either be
 *		"dvr" or "demux_filter".
 */
struct dvb_vb2_ctx {
	struct vb2_queue	vb_q;
	struct mutex		mutex;
	spinlock_t		slock;
	struct list_head	dvb_q;
	struct dvb_buffer	*buf;
	int	offset;
	int	remain;
	int	state;
	int	buf_siz;
	int	buf_cnt;
	int	nonblocking;

	enum dmx_buffer_flags flags;
	u32	count;

	char	name[DVB_VB2_NAME_MAX + 1];
};

#ifndef CONFIG_DVB_MMAP
static inline int dvb_vb2_init(struct dvb_vb2_ctx *ctx,
			       const char *name, int non_blocking)
{
	return 0;
};
static inline int dvb_vb2_release(struct dvb_vb2_ctx *ctx)
{
	return 0;
};
#define dvb_vb2_is_streaming(ctx) (0)
#define dvb_vb2_fill_buffer(ctx, file, wait, flags) (0)

static inline __poll_t dvb_vb2_poll(struct dvb_vb2_ctx *ctx,
				    struct file *file,
				    poll_table *wait)
{
	return 0;
}
#else
/**
 * dvb_vb2_init - initializes VB2 handler
 *
 * @ctx:	control struct for VB2 handler
 * @name:	name for the VB2 handler
 * @non_blocking:
 *		if not zero, it means that the device is at non-blocking mode
 */
int dvb_vb2_init(struct dvb_vb2_ctx *ctx, const char *name, int non_blocking);

/**
 * dvb_vb2_release - Releases the VB2 handler allocated resources and
 *	put @ctx at DVB_VB2_STATE_NONE state.
 * @ctx:	control struct for VB2 handler
 */
int dvb_vb2_release(struct dvb_vb2_ctx *ctx);

/**
 * dvb_vb2_is_streaming - checks if the VB2 handler is streaming
 * @ctx:	control struct for VB2 handler
 *
 * Return: 0 if not streaming, 1 otherwise.
 */
int dvb_vb2_is_streaming(struct dvb_vb2_ctx *ctx);

/**
 * dvb_vb2_fill_buffer - fills a VB2 buffer
 * @ctx:	control struct for VB2 handler
 * @src:	place where the data is stored
 * @len:	number of bytes to be copied from @src
 * @buffer_flags:
 *		pointer to buffer flags as defined by &enum dmx_buffer_flags.
 *		can be NULL.
 */
int dvb_vb2_fill_buffer(struct dvb_vb2_ctx *ctx,
			const unsigned char *src, int len,
			enum dmx_buffer_flags *buffer_flags);

/**
 * dvb_vb2_poll - Wrapper to vb2_core_streamon() for Digital TV
 *      buffer handling.
 *
 * @ctx:	control struct for VB2 handler
 * @file:	&struct file argument passed to the poll
 *		file operation handler.
 * @wait:	&poll_table wait argument passed to the poll
 *		file operation handler.
 *
 * Implements poll syscall() logic.
 */
__poll_t dvb_vb2_poll(struct dvb_vb2_ctx *ctx, struct file *file,
		      poll_table *wait);
#endif

/**
 * dvb_vb2_stream_on() - Wrapper to vb2_core_streamon() for Digital TV
 *	buffer handling.
 *
 * @ctx:	control struct for VB2 handler
 *
 * Starts dvb streaming
 */
int dvb_vb2_stream_on(struct dvb_vb2_ctx *ctx);
/**
 * dvb_vb2_stream_off() - Wrapper to vb2_core_streamoff() for Digital TV
 *	buffer handling.
 *
 * @ctx:	control struct for VB2 handler
 *
 * Stops dvb streaming
 */
int dvb_vb2_stream_off(struct dvb_vb2_ctx *ctx);

/**
 * dvb_vb2_reqbufs() - Wrapper to vb2_core_reqbufs() for Digital TV
 *	buffer handling.
 *
 * @ctx:	control struct for VB2 handler
 * @req:	&struct dmx_requestbuffers passed from userspace in
 *		order to handle &DMX_REQBUFS.
 *
 * Initiate streaming by requesting a number of buffers. Also used to
 * free previously requested buffers, is ``req->count`` is zero.
 */
int dvb_vb2_reqbufs(struct dvb_vb2_ctx *ctx, struct dmx_requestbuffers *req);

/**
 * dvb_vb2_querybuf() - Wrapper to vb2_core_querybuf() for Digital TV
 *	buffer handling.
 *
 * @ctx:	control struct for VB2 handler
 * @b:		&struct dmx_buffer passed from userspace in
 *		order to handle &DMX_QUERYBUF.
 *
 *
 */
int dvb_vb2_querybuf(struct dvb_vb2_ctx *ctx, struct dmx_buffer *b);

/**
 * dvb_vb2_expbuf() - Wrapper to vb2_core_expbuf() for Digital TV
 *	buffer handling.
 *
 * @ctx:	control struct for VB2 handler
 * @exp:	&struct dmx_exportbuffer passed from userspace in
 *		order to handle &DMX_EXPBUF.
 *
 * Export a buffer as a file descriptor.
 */
int dvb_vb2_expbuf(struct dvb_vb2_ctx *ctx, struct dmx_exportbuffer *exp);

/**
 * dvb_vb2_qbuf() - Wrapper to vb2_core_qbuf() for Digital TV buffer handling.
 *
 * @ctx:	control struct for VB2 handler
 * @b:		&struct dmx_buffer passed from userspace in
 *		order to handle &DMX_QBUF.
 *
 * Queue a Digital TV buffer as requested by userspace
 */
int dvb_vb2_qbuf(struct dvb_vb2_ctx *ctx, struct dmx_buffer *b);

/**
 * dvb_vb2_dqbuf() - Wrapper to vb2_core_dqbuf() for Digital TV
 *	buffer handling.
 *
 * @ctx:	control struct for VB2 handler
 * @b:		&struct dmx_buffer passed from userspace in
 *		order to handle &DMX_DQBUF.
 *
 * Dequeue a Digital TV buffer to the userspace
 */
int dvb_vb2_dqbuf(struct dvb_vb2_ctx *ctx, struct dmx_buffer *b);

/**
 * dvb_vb2_mmap() - Wrapper to vb2_mmap() for Digital TV buffer handling.
 *
 * @ctx:	control struct for VB2 handler
 * @vma:        pointer to &struct vm_area_struct with the vma passed
 *              to the mmap file operation handler in the driver.
 *
 * map Digital TV video buffers into application address space.
 */
int dvb_vb2_mmap(struct dvb_vb2_ctx *ctx, struct vm_area_struct *vma);

#endif /* _DVB_VB2_H */