From 9f577d6db5bf7d76fb9e26894a92fcb4ecb4c832 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Fri, 29 Dec 2017 08:23:41 -0500 Subject: media: dvb kAPI docs: document dvb_vb2.h Document the data structures and functions inside this kAPI header. Signed-off-by: Mauro Carvalho Chehab --- include/media/dmxdev.h | 2 + include/media/dvb_vb2.h | 183 ++++++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 179 insertions(+), 6 deletions(-) (limited to 'include/media') diff --git a/include/media/dmxdev.h b/include/media/dmxdev.h index d5bef0da2e6e..2f5cb2c7b6a7 100644 --- a/include/media/dmxdev.h +++ b/include/media/dmxdev.h @@ -112,6 +112,7 @@ struct dmxdev_feed { * @state: state of the dmxdev filter, as defined by &enum dmxdev_state. * @dev: pointer to &struct dmxdev. * @buffer: an embedded &struct dvb_ringbuffer buffer. + * @vb2_ctx: control struct for VB2 handler * @mutex: protects the access to &struct dmxdev_filter. * @timer: &struct timer_list embedded timer, used to check for * feed timeouts. @@ -165,6 +166,7 @@ struct dmxdev_filter { * @exit: flag to indicate that the demux is being released. * @dvr_orig_fe: pointer to &struct dmx_frontend. * @dvr_buffer: embedded &struct dvb_ringbuffer for DVB output. + * @dvr_vb2_ctx: control struct for VB2 handler * @mutex: protects the usage of this structure. * @lock: protects access to &dmxdev->filter->data. */ diff --git a/include/media/dvb_vb2.h b/include/media/dvb_vb2.h index ef4a802f7435..5431e5a7e140 100644 --- a/include/media/dvb_vb2.h +++ b/include/media/dvb_vb2.h @@ -22,22 +22,72 @@ #include #include +/** + * 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, }; -#define DVB_VB2_STATE_NONE (0x0) -#define DVB_VB2_STATE_INIT (0x1) -#define DVB_VB2_STATE_REQBUFS (0x2) -#define DVB_VB2_STATE_STREAMON (0x4) +/** + * 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. + * @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; @@ -53,8 +103,6 @@ struct dvb_vb2_ctx { char name[DVB_VB2_NAME_MAX + 1]; }; -int dvb_vb2_stream_on(struct dvb_vb2_ctx *ctx); -int dvb_vb2_stream_off(struct dvb_vb2_ctx *ctx); #ifndef DVB_MMAP static inline int dvb_vb2_init(struct dvb_vb2_ctx *ctx, const char *name, int non_blocking) @@ -75,21 +123,144 @@ static inline unsigned int dvb_vb2_poll(struct dvb_vb2_ctx *ctx, 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 + */ int dvb_vb2_fill_buffer(struct dvb_vb2_ctx *ctx, const unsigned char *src, int len); + +/** + * 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. + */ unsigned int 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 */ -- cgit v1.2.3