/*
 * 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 */