include/media/dvb_vb2.h

   1 /*
   2  * SPDX-License-Identifier: GPL-2.0
   3  *
   4  * dvb-vb2.h - DVB driver helper framework for streaming I/O
   5  *
   6  * Copyright (C) 2015 Samsung Electronics
   7  *
   8  * Author: jh1009.sung@samsung.com
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation.
  13  */
  14
  15 #ifndef _DVB_VB2_H
  16 #define _DVB_VB2_H
  17
  18 #include <linux/mutex.h>
  19 #include <linux/poll.h>
  20 #include <linux/dvb/dmx.h>
  21 #include <media/videobuf2-core.h>
  22 #include <media/videobuf2-dma-contig.h>
  23 #include <media/videobuf2-vmalloc.h>
  24
  25 /**
  26  * enum dvb_buf_type - types of Digital TV memory-mapped buffers
  27  *
  28  * @DVB_BUF_TYPE_CAPTURE: buffer is filled by the Kernel,
  29  *                        with a received Digital TV stream
  30  */
  31 enum dvb_buf_type {
  32         DVB_BUF_TYPE_CAPTURE        = 1,
  33 };
  34
  35 /**
  36  * enum dvb_vb2_states - states to control VB2 state machine
  37  * @DVB_VB2_STATE_NONE:
  38  *      VB2 engine not initialized yet, init failed or VB2 was released.
  39  * @DVB_VB2_STATE_INIT:
  40  *      VB2 engine initialized.
  41  * @DVB_VB2_STATE_REQBUFS:
  42  *      Buffers were requested
  43  * @DVB_VB2_STATE_STREAMON:
  44  *      VB2 is streaming. Callers should not check it directly. Instead,
  45  *      they should use dvb_vb2_is_streaming().
  46  *
  47  * Note:
  48  *
  49  * Callers should not touch at the state machine directly. This
  50  * is handled inside dvb_vb2.c.
  51  */
  52 enum dvb_vb2_states {
  53         DVB_VB2_STATE_NONE      = 0x0,
  54         DVB_VB2_STATE_INIT      = 0x1,
  55         DVB_VB2_STATE_REQBUFS   = 0x2,
  56         DVB_VB2_STATE_STREAMON  = 0x4,
  57 };
  58
  59 #define DVB_VB2_NAME_MAX (20)
  60
  61 /**
  62  * struct dvb_buffer - video buffer information for v4l2.
  63  *
  64  * @vb:         embedded struct &vb2_buffer.
  65  * @list:       list of &struct dvb_buffer.
  66  */
  67 struct dvb_buffer {
  68         struct vb2_buffer       vb;
  69         struct list_head        list;
  70 };
  71
  72 /**
  73  * struct dvb_vb2_ctx - control struct for VB2 handler
  74  * @vb_q:       pointer to &struct vb2_queue with videobuf2 queue.
  75  * @mutex:      mutex to serialize vb2 operations. Used by
  76  *              vb2 core %wait_prepare and %wait_finish operations.
  77  * @slock:      spin lock used to protect buffer filling at dvb_vb2.c.
  78  * @dvb_q:      List of buffers that are not filled yet.
  79  * @buf:        Pointer to the buffer that are currently being filled.
  80  * @offset:     index to the next position at the @buf to be filled.
  81  * @remain:     How many bytes are left to be filled at @buf.
  82  * @state:      bitmask of buffer states as defined by &enum dvb_vb2_states.
  83  * @buf_siz:    size of each VB2 buffer.
  84  * @buf_cnt:    number of VB2 buffers.
  85  * @nonblocking:
  86  *              If different than zero, device is operating on non-blocking
  87  *              mode.
  88  * @name:       name of the device type. Currently, it can either be
  89  *              "dvr" or "demux_filter".
  90  */
  91 struct dvb_vb2_ctx {
  92         struct vb2_queue        vb_q;
  93         struct mutex            mutex;
  94         spinlock_t              slock;
  95         struct list_head        dvb_q;
  96         struct dvb_buffer       *buf;
  97         int     offset;
  98         int     remain;
  99         int     state;
 100         int     buf_siz;
 101         int     buf_cnt;
 102         int     nonblocking;
 103         char    name[DVB_VB2_NAME_MAX + 1];
 104 };
 105
 106 #ifndef DVB_MMAP
 107 static inline int dvb_vb2_init(struct dvb_vb2_ctx *ctx,
 108                                const char *name, int non_blocking)
 109 {
 110         return 0;
 111 };
 112 static inline int dvb_vb2_release(struct dvb_vb2_ctx *ctx)
 113 {
 114         return 0;
 115 };
 116 #define dvb_vb2_is_streaming(ctx) (0)
 117 #define dvb_vb2_fill_buffer(ctx, file, wait) (0)
 118
 119 static inline __poll_t dvb_vb2_poll(struct dvb_vb2_ctx *ctx,
 120                                     struct file *file,
 121                                     poll_table *wait)
 122 {
 123         return 0;
 124 }
 125 #else
 126 /**
 127  * dvb_vb2_init - initializes VB2 handler
 128  *
 129  * @ctx:        control struct for VB2 handler
 130  * @name:       name for the VB2 handler
 131  * @non_blocking:
 132  *              if not zero, it means that the device is at non-blocking mode
 133  */
 134 int dvb_vb2_init(struct dvb_vb2_ctx *ctx, const char *name, int non_blocking);
 135
 136 /**
 137  * dvb_vb2_release - Releases the VB2 handler allocated resources and
 138  *      put @ctx at DVB_VB2_STATE_NONE state.
 139  * @ctx:        control struct for VB2 handler
 140  */
 141 int dvb_vb2_release(struct dvb_vb2_ctx *ctx);
 142
 143 /**
 144  * dvb_vb2_is_streaming - checks if the VB2 handler is streaming
 145  * @ctx:        control struct for VB2 handler
 146  *
 147  * Return: 0 if not streaming, 1 otherwise.
 148  */
 149 int dvb_vb2_is_streaming(struct dvb_vb2_ctx *ctx);
 150
 151 /**
 152  * dvb_vb2_fill_buffer - fills a VB2 buffer
 153  * @ctx:        control struct for VB2 handler
 154  * @src:        place where the data is stored
 155  * @len:        number of bytes to be copied from @src
 156  */
 157 int dvb_vb2_fill_buffer(struct dvb_vb2_ctx *ctx,
 158                         const unsigned char *src, int len);
 159
 160 /**
 161  * dvb_vb2_poll - Wrapper to vb2_core_streamon() for Digital TV
 162  *      buffer handling.
 163  *
 164  * @ctx:        control struct for VB2 handler
 165  * @file:       &struct file argument passed to the poll
 166  *              file operation handler.
 167  * @wait:       &poll_table wait argument passed to the poll
 168  *              file operation handler.
 169  *
 170  * Implements poll syscall() logic.
 171  */
 172 __poll_t dvb_vb2_poll(struct dvb_vb2_ctx *ctx, struct file *file,
 173                       poll_table *wait);
 174 #endif
 175
 176 /**
 177  * dvb_vb2_stream_on() - Wrapper to vb2_core_streamon() for Digital TV
 178  *      buffer handling.
 179  *
 180  * @ctx:        control struct for VB2 handler
 181  *
 182  * Starts dvb streaming
 183  */
 184 int dvb_vb2_stream_on(struct dvb_vb2_ctx *ctx);
 185 /**
 186  * dvb_vb2_stream_off() - Wrapper to vb2_core_streamoff() for Digital TV
 187  *      buffer handling.
 188  *
 189  * @ctx:        control struct for VB2 handler
 190  *
 191  * Stops dvb streaming
 192  */
 193 int dvb_vb2_stream_off(struct dvb_vb2_ctx *ctx);
 194
 195 /**
 196  * dvb_vb2_reqbufs() - Wrapper to vb2_core_reqbufs() for Digital TV
 197  *      buffer handling.
 198  *
 199  * @ctx:        control struct for VB2 handler
 200  * @req:        &struct dmx_requestbuffers passed from userspace in
 201  *              order to handle &DMX_REQBUFS.
 202  *
 203  * Initiate streaming by requesting a number of buffers. Also used to
 204  * free previously requested buffers, is ``req->count`` is zero.
 205  */
 206 int dvb_vb2_reqbufs(struct dvb_vb2_ctx *ctx, struct dmx_requestbuffers *req);
 207
 208 /**
 209  * dvb_vb2_querybuf() - Wrapper to vb2_core_querybuf() for Digital TV
 210  *      buffer handling.
 211  *
 212  * @ctx:        control struct for VB2 handler
 213  * @b:          &struct dmx_buffer passed from userspace in
 214  *              order to handle &DMX_QUERYBUF.
 215  *
 216  *
 217  */
 218 int dvb_vb2_querybuf(struct dvb_vb2_ctx *ctx, struct dmx_buffer *b);
 219
 220 /**
 221  * dvb_vb2_expbuf() - Wrapper to vb2_core_expbuf() for Digital TV
 222  *      buffer handling.
 223  *
 224  * @ctx:        control struct for VB2 handler
 225  * @exp:        &struct dmx_exportbuffer passed from userspace in
 226  *              order to handle &DMX_EXPBUF.
 227  *
 228  * Export a buffer as a file descriptor.
 229  */
 230 int dvb_vb2_expbuf(struct dvb_vb2_ctx *ctx, struct dmx_exportbuffer *exp);
 231
 232 /**
 233  * dvb_vb2_qbuf() - Wrapper to vb2_core_qbuf() for Digital TV buffer handling.
 234  *
 235  * @ctx:        control struct for VB2 handler
 236  * @b:          &struct dmx_buffer passed from userspace in
 237  *              order to handle &DMX_QBUF.
 238  *
 239  * Queue a Digital TV buffer as requested by userspace
 240  */
 241 int dvb_vb2_qbuf(struct dvb_vb2_ctx *ctx, struct dmx_buffer *b);
 242
 243 /**
 244  * dvb_vb2_dqbuf() - Wrapper to vb2_core_dqbuf() for Digital TV
 245  *      buffer handling.
 246  *
 247  * @ctx:        control struct for VB2 handler
 248  * @b:          &struct dmx_buffer passed from userspace in
 249  *              order to handle &DMX_DQBUF.
 250  *
 251  * Dequeue a Digital TV buffer to the userspace
 252  */
 253 int dvb_vb2_dqbuf(struct dvb_vb2_ctx *ctx, struct dmx_buffer *b);
 254
 255 /**
 256  * dvb_vb2_mmap() - Wrapper to vb2_mmap() for Digital TV buffer handling.
 257  *
 258  * @ctx:        control struct for VB2 handler
 259  * @vma:        pointer to &struct vm_area_struct with the vma passed
 260  *              to the mmap file operation handler in the driver.
 261  *
 262  * map Digital TV video buffers into application address space.
 263  */
 264 int dvb_vb2_mmap(struct dvb_vb2_ctx *ctx, struct vm_area_struct *vma);
 265
 266 #endif /* _DVB_VB2_H */