LCOV - code coverage report
Current view: top level - include/media - videobuf2-core.h (source / functions) Hit Total Coverage
Test: Real Lines: 0 10 0.0 %
Date: 2020-10-17 15:46:16 Functions: 0 0 -
Legend: Neither, QEMU, Real, Both Branches: 0 0 -

           Branch data     Line data    Source code
       1                 :            : /*
       2                 :            :  * videobuf2-core.h - Video Buffer 2 Core Framework
       3                 :            :  *
       4                 :            :  * Copyright (C) 2010 Samsung Electronics
       5                 :            :  *
       6                 :            :  * Author: Pawel Osciak <pawel@osciak.com>
       7                 :            :  *
       8                 :            :  * This program is free software; you can redistribute it and/or modify
       9                 :            :  * it under the terms of the GNU General Public License as published by
      10                 :            :  * the Free Software Foundation.
      11                 :            :  */
      12                 :            : #ifndef _MEDIA_VIDEOBUF2_CORE_H
      13                 :            : #define _MEDIA_VIDEOBUF2_CORE_H
      14                 :            : 
      15                 :            : #include <linux/mm_types.h>
      16                 :            : #include <linux/mutex.h>
      17                 :            : #include <linux/poll.h>
      18                 :            : #include <linux/dma-buf.h>
      19                 :            : #include <linux/bitops.h>
      20                 :            : #include <media/media-request.h>
      21                 :            : 
      22                 :            : #define VB2_MAX_FRAME   (32)
      23                 :            : #define VB2_MAX_PLANES  (8)
      24                 :            : 
      25                 :            : /**
      26                 :            :  * enum vb2_memory - type of memory model used to make the buffers visible
      27                 :            :  *      on userspace.
      28                 :            :  *
      29                 :            :  * @VB2_MEMORY_UNKNOWN: Buffer status is unknown or it is not used yet on
      30                 :            :  *                      userspace.
      31                 :            :  * @VB2_MEMORY_MMAP:    The buffers are allocated by the Kernel and it is
      32                 :            :  *                      memory mapped via mmap() ioctl. This model is
      33                 :            :  *                      also used when the user is using the buffers via
      34                 :            :  *                      read() or write() system calls.
      35                 :            :  * @VB2_MEMORY_USERPTR: The buffers was allocated in userspace and it is
      36                 :            :  *                      memory mapped via mmap() ioctl.
      37                 :            :  * @VB2_MEMORY_DMABUF:  The buffers are passed to userspace via DMA buffer.
      38                 :            :  */
      39                 :            : enum vb2_memory {
      40                 :            :         VB2_MEMORY_UNKNOWN      = 0,
      41                 :            :         VB2_MEMORY_MMAP         = 1,
      42                 :            :         VB2_MEMORY_USERPTR      = 2,
      43                 :            :         VB2_MEMORY_DMABUF       = 4,
      44                 :            : };
      45                 :            : 
      46                 :            : struct vb2_fileio_data;
      47                 :            : struct vb2_threadio_data;
      48                 :            : 
      49                 :            : /**
      50                 :            :  * struct vb2_mem_ops - memory handling/memory allocator operations.
      51                 :            :  * @alloc:      allocate video memory and, optionally, allocator private data,
      52                 :            :  *              return ERR_PTR() on failure or a pointer to allocator private,
      53                 :            :  *              per-buffer data on success; the returned private structure
      54                 :            :  *              will then be passed as @buf_priv argument to other ops in this
      55                 :            :  *              structure. Additional gfp_flags to use when allocating the
      56                 :            :  *              are also passed to this operation. These flags are from the
      57                 :            :  *              gfp_flags field of vb2_queue. The size argument to this function
      58                 :            :  *              shall be *page aligned*.
      59                 :            :  * @put:        inform the allocator that the buffer will no longer be used;
      60                 :            :  *              usually will result in the allocator freeing the buffer (if
      61                 :            :  *              no other users of this buffer are present); the @buf_priv
      62                 :            :  *              argument is the allocator private per-buffer structure
      63                 :            :  *              previously returned from the alloc callback.
      64                 :            :  * @get_dmabuf: acquire userspace memory for a hardware operation; used for
      65                 :            :  *               DMABUF memory types.
      66                 :            :  * @get_userptr: acquire userspace memory for a hardware operation; used for
      67                 :            :  *               USERPTR memory types; vaddr is the address passed to the
      68                 :            :  *               videobuf layer when queuing a video buffer of USERPTR type;
      69                 :            :  *               should return an allocator private per-buffer structure
      70                 :            :  *               associated with the buffer on success, ERR_PTR() on failure;
      71                 :            :  *               the returned private structure will then be passed as @buf_priv
      72                 :            :  *               argument to other ops in this structure.
      73                 :            :  * @put_userptr: inform the allocator that a USERPTR buffer will no longer
      74                 :            :  *               be used.
      75                 :            :  * @attach_dmabuf: attach a shared &struct dma_buf for a hardware operation;
      76                 :            :  *                 used for DMABUF memory types; dev is the alloc device
      77                 :            :  *                 dbuf is the shared dma_buf; returns ERR_PTR() on failure;
      78                 :            :  *                 allocator private per-buffer structure on success;
      79                 :            :  *                 this needs to be used for further accesses to the buffer.
      80                 :            :  * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
      81                 :            :  *                 buffer is no longer used; the @buf_priv argument is the
      82                 :            :  *                 allocator private per-buffer structure previously returned
      83                 :            :  *                 from the attach_dmabuf callback.
      84                 :            :  * @map_dmabuf: request for access to the dmabuf from allocator; the allocator
      85                 :            :  *              of dmabuf is informed that this driver is going to use the
      86                 :            :  *              dmabuf.
      87                 :            :  * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
      88                 :            :  *                that this driver is done using the dmabuf for now.
      89                 :            :  * @prepare:    called every time the buffer is passed from userspace to the
      90                 :            :  *              driver, useful for cache synchronisation, optional.
      91                 :            :  * @finish:     called every time the buffer is passed back from the driver
      92                 :            :  *              to the userspace, also optional.
      93                 :            :  * @vaddr:      return a kernel virtual address to a given memory buffer
      94                 :            :  *              associated with the passed private structure or NULL if no
      95                 :            :  *              such mapping exists.
      96                 :            :  * @cookie:     return allocator specific cookie for a given memory buffer
      97                 :            :  *              associated with the passed private structure or NULL if not
      98                 :            :  *              available.
      99                 :            :  * @num_users:  return the current number of users of a memory buffer;
     100                 :            :  *              return 1 if the videobuf layer (or actually the driver using
     101                 :            :  *              it) is the only user.
     102                 :            :  * @mmap:       setup a userspace mapping for a given memory buffer under
     103                 :            :  *              the provided virtual memory region.
     104                 :            :  *
     105                 :            :  * Those operations are used by the videobuf2 core to implement the memory
     106                 :            :  * handling/memory allocators for each type of supported streaming I/O method.
     107                 :            :  *
     108                 :            :  * .. note::
     109                 :            :  *    #) Required ops for USERPTR types: get_userptr, put_userptr.
     110                 :            :  *
     111                 :            :  *    #) Required ops for MMAP types: alloc, put, num_users, mmap.
     112                 :            :  *
     113                 :            :  *    #) Required ops for read/write access types: alloc, put, num_users, vaddr.
     114                 :            :  *
     115                 :            :  *    #) Required ops for DMABUF types: attach_dmabuf, detach_dmabuf,
     116                 :            :  *       map_dmabuf, unmap_dmabuf.
     117                 :            :  */
     118                 :            : struct vb2_mem_ops {
     119                 :            :         void            *(*alloc)(struct device *dev, unsigned long attrs,
     120                 :            :                                   unsigned long size,
     121                 :            :                                   enum dma_data_direction dma_dir,
     122                 :            :                                   gfp_t gfp_flags);
     123                 :            :         void            (*put)(void *buf_priv);
     124                 :            :         struct dma_buf *(*get_dmabuf)(void *buf_priv, unsigned long flags);
     125                 :            : 
     126                 :            :         void            *(*get_userptr)(struct device *dev, unsigned long vaddr,
     127                 :            :                                         unsigned long size,
     128                 :            :                                         enum dma_data_direction dma_dir);
     129                 :            :         void            (*put_userptr)(void *buf_priv);
     130                 :            : 
     131                 :            :         void            (*prepare)(void *buf_priv);
     132                 :            :         void            (*finish)(void *buf_priv);
     133                 :            : 
     134                 :            :         void            *(*attach_dmabuf)(struct device *dev,
     135                 :            :                                           struct dma_buf *dbuf,
     136                 :            :                                           unsigned long size,
     137                 :            :                                           enum dma_data_direction dma_dir);
     138                 :            :         void            (*detach_dmabuf)(void *buf_priv);
     139                 :            :         int             (*map_dmabuf)(void *buf_priv);
     140                 :            :         void            (*unmap_dmabuf)(void *buf_priv);
     141                 :            : 
     142                 :            :         void            *(*vaddr)(void *buf_priv);
     143                 :            :         void            *(*cookie)(void *buf_priv);
     144                 :            : 
     145                 :            :         unsigned int    (*num_users)(void *buf_priv);
     146                 :            : 
     147                 :            :         int             (*mmap)(void *buf_priv, struct vm_area_struct *vma);
     148                 :            : };
     149                 :            : 
     150                 :            : /**
     151                 :            :  * struct vb2_plane - plane information.
     152                 :            :  * @mem_priv:   private data with this plane.
     153                 :            :  * @dbuf:       dma_buf - shared buffer object.
     154                 :            :  * @dbuf_mapped:        flag to show whether dbuf is mapped or not
     155                 :            :  * @bytesused:  number of bytes occupied by data in the plane (payload).
     156                 :            :  * @length:     size of this plane (NOT the payload) in bytes.
     157                 :            :  * @min_length: minimum required size of this plane (NOT the payload) in bytes.
     158                 :            :  *              @length is always greater or equal to @min_length.
     159                 :            :  * @m:          Union with memtype-specific data.
     160                 :            :  * @m.offset:   when memory in the associated struct vb2_buffer is
     161                 :            :  *              %VB2_MEMORY_MMAP, equals the offset from the start of
     162                 :            :  *              the device memory for this plane (or is a "cookie" that
     163                 :            :  *              should be passed to mmap() called on the video node).
     164                 :            :  * @m.userptr:  when memory is %VB2_MEMORY_USERPTR, a userspace pointer
     165                 :            :  *              pointing to this plane.
     166                 :            :  * @m.fd:       when memory is %VB2_MEMORY_DMABUF, a userspace file
     167                 :            :  *              descriptor associated with this plane.
     168                 :            :  * @data_offset:        offset in the plane to the start of data; usually 0,
     169                 :            :  *              unless there is a header in front of the data.
     170                 :            :  *
     171                 :            :  * Should contain enough information to be able to cover all the fields
     172                 :            :  * of &struct v4l2_plane at videodev2.h.
     173                 :            :  */
     174                 :            : struct vb2_plane {
     175                 :            :         void                    *mem_priv;
     176                 :            :         struct dma_buf          *dbuf;
     177                 :            :         unsigned int            dbuf_mapped;
     178                 :            :         unsigned int            bytesused;
     179                 :            :         unsigned int            length;
     180                 :            :         unsigned int            min_length;
     181                 :            :         union {
     182                 :            :                 unsigned int    offset;
     183                 :            :                 unsigned long   userptr;
     184                 :            :                 int             fd;
     185                 :            :         } m;
     186                 :            :         unsigned int            data_offset;
     187                 :            : };
     188                 :            : 
     189                 :            : /**
     190                 :            :  * enum vb2_io_modes - queue access methods.
     191                 :            :  * @VB2_MMAP:           driver supports MMAP with streaming API.
     192                 :            :  * @VB2_USERPTR:        driver supports USERPTR with streaming API.
     193                 :            :  * @VB2_READ:           driver supports read() style access.
     194                 :            :  * @VB2_WRITE:          driver supports write() style access.
     195                 :            :  * @VB2_DMABUF:         driver supports DMABUF with streaming API.
     196                 :            :  */
     197                 :            : enum vb2_io_modes {
     198                 :            :         VB2_MMAP        = BIT(0),
     199                 :            :         VB2_USERPTR     = BIT(1),
     200                 :            :         VB2_READ        = BIT(2),
     201                 :            :         VB2_WRITE       = BIT(3),
     202                 :            :         VB2_DMABUF      = BIT(4),
     203                 :            : };
     204                 :            : 
     205                 :            : /**
     206                 :            :  * enum vb2_buffer_state - current video buffer state.
     207                 :            :  * @VB2_BUF_STATE_DEQUEUED:     buffer under userspace control.
     208                 :            :  * @VB2_BUF_STATE_IN_REQUEST:   buffer is queued in media request.
     209                 :            :  * @VB2_BUF_STATE_PREPARING:    buffer is being prepared in videobuf.
     210                 :            :  * @VB2_BUF_STATE_QUEUED:       buffer queued in videobuf, but not in driver.
     211                 :            :  * @VB2_BUF_STATE_ACTIVE:       buffer queued in driver and possibly used
     212                 :            :  *                              in a hardware operation.
     213                 :            :  * @VB2_BUF_STATE_DONE:         buffer returned from driver to videobuf, but
     214                 :            :  *                              not yet dequeued to userspace.
     215                 :            :  * @VB2_BUF_STATE_ERROR:        same as above, but the operation on the buffer
     216                 :            :  *                              has ended with an error, which will be reported
     217                 :            :  *                              to the userspace when it is dequeued.
     218                 :            :  */
     219                 :            : enum vb2_buffer_state {
     220                 :            :         VB2_BUF_STATE_DEQUEUED,
     221                 :            :         VB2_BUF_STATE_IN_REQUEST,
     222                 :            :         VB2_BUF_STATE_PREPARING,
     223                 :            :         VB2_BUF_STATE_QUEUED,
     224                 :            :         VB2_BUF_STATE_ACTIVE,
     225                 :            :         VB2_BUF_STATE_DONE,
     226                 :            :         VB2_BUF_STATE_ERROR,
     227                 :            : };
     228                 :            : 
     229                 :            : struct vb2_queue;
     230                 :            : 
     231                 :            : /**
     232                 :            :  * struct vb2_buffer - represents a video buffer.
     233                 :            :  * @vb2_queue:          pointer to &struct vb2_queue with the queue to
     234                 :            :  *                      which this driver belongs.
     235                 :            :  * @index:              id number of the buffer.
     236                 :            :  * @type:               buffer type.
     237                 :            :  * @memory:             the method, in which the actual data is passed.
     238                 :            :  * @num_planes:         number of planes in the buffer
     239                 :            :  *                      on an internal driver queue.
     240                 :            :  * @timestamp:          frame timestamp in ns.
     241                 :            :  * @request:            the request this buffer is associated with.
     242                 :            :  * @req_obj:            used to bind this buffer to a request. This
     243                 :            :  *                      request object has a refcount.
     244                 :            :  */
     245                 :            : struct vb2_buffer {
     246                 :            :         struct vb2_queue        *vb2_queue;
     247                 :            :         unsigned int            index;
     248                 :            :         unsigned int            type;
     249                 :            :         unsigned int            memory;
     250                 :            :         unsigned int            num_planes;
     251                 :            :         u64                     timestamp;
     252                 :            :         struct media_request    *request;
     253                 :            :         struct media_request_object     req_obj;
     254                 :            : 
     255                 :            :         /* private: internal use only
     256                 :            :          *
     257                 :            :          * state:               current buffer state; do not change
     258                 :            :          * synced:              this buffer has been synced for DMA, i.e. the
     259                 :            :          *                      'prepare' memop was called. It is cleared again
     260                 :            :          *                      after the 'finish' memop is called.
     261                 :            :          * prepared:            this buffer has been prepared, i.e. the
     262                 :            :          *                      buf_prepare op was called. It is cleared again
     263                 :            :          *                      after the 'buf_finish' op is called.
     264                 :            :          * copied_timestamp:    the timestamp of this capture buffer was copied
     265                 :            :          *                      from an output buffer.
     266                 :            :          * queued_entry:        entry on the queued buffers list, which holds
     267                 :            :          *                      all buffers queued from userspace
     268                 :            :          * done_entry:          entry on the list that stores all buffers ready
     269                 :            :          *                      to be dequeued to userspace
     270                 :            :          * vb2_plane:           per-plane information; do not change
     271                 :            :          */
     272                 :            :         enum vb2_buffer_state   state;
     273                 :            :         unsigned int            synced:1;
     274                 :            :         unsigned int            prepared:1;
     275                 :            :         unsigned int            copied_timestamp:1;
     276                 :            : 
     277                 :            :         struct vb2_plane        planes[VB2_MAX_PLANES];
     278                 :            :         struct list_head        queued_entry;
     279                 :            :         struct list_head        done_entry;
     280                 :            : #ifdef CONFIG_VIDEO_ADV_DEBUG
     281                 :            :         /*
     282                 :            :          * Counters for how often these buffer-related ops are
     283                 :            :          * called. Used to check for unbalanced ops.
     284                 :            :          */
     285                 :            :         u32             cnt_mem_alloc;
     286                 :            :         u32             cnt_mem_put;
     287                 :            :         u32             cnt_mem_get_dmabuf;
     288                 :            :         u32             cnt_mem_get_userptr;
     289                 :            :         u32             cnt_mem_put_userptr;
     290                 :            :         u32             cnt_mem_prepare;
     291                 :            :         u32             cnt_mem_finish;
     292                 :            :         u32             cnt_mem_attach_dmabuf;
     293                 :            :         u32             cnt_mem_detach_dmabuf;
     294                 :            :         u32             cnt_mem_map_dmabuf;
     295                 :            :         u32             cnt_mem_unmap_dmabuf;
     296                 :            :         u32             cnt_mem_vaddr;
     297                 :            :         u32             cnt_mem_cookie;
     298                 :            :         u32             cnt_mem_num_users;
     299                 :            :         u32             cnt_mem_mmap;
     300                 :            : 
     301                 :            :         u32             cnt_buf_out_validate;
     302                 :            :         u32             cnt_buf_init;
     303                 :            :         u32             cnt_buf_prepare;
     304                 :            :         u32             cnt_buf_finish;
     305                 :            :         u32             cnt_buf_cleanup;
     306                 :            :         u32             cnt_buf_queue;
     307                 :            :         u32             cnt_buf_request_complete;
     308                 :            : 
     309                 :            :         /* This counts the number of calls to vb2_buffer_done() */
     310                 :            :         u32             cnt_buf_done;
     311                 :            : #endif
     312                 :            : };
     313                 :            : 
     314                 :            : /**
     315                 :            :  * struct vb2_ops - driver-specific callbacks.
     316                 :            :  *
     317                 :            :  * These operations are not called from interrupt context except where
     318                 :            :  * mentioned specifically.
     319                 :            :  *
     320                 :            :  * @queue_setup:        called from VIDIOC_REQBUFS() and VIDIOC_CREATE_BUFS()
     321                 :            :  *                      handlers before memory allocation. It can be called
     322                 :            :  *                      twice: if the original number of requested buffers
     323                 :            :  *                      could not be allocated, then it will be called a
     324                 :            :  *                      second time with the actually allocated number of
     325                 :            :  *                      buffers to verify if that is OK.
     326                 :            :  *                      The driver should return the required number of buffers
     327                 :            :  *                      in \*num_buffers, the required number of planes per
     328                 :            :  *                      buffer in \*num_planes, the size of each plane should be
     329                 :            :  *                      set in the sizes\[\] array and optional per-plane
     330                 :            :  *                      allocator specific device in the alloc_devs\[\] array.
     331                 :            :  *                      When called from VIDIOC_REQBUFS(), \*num_planes == 0,
     332                 :            :  *                      the driver has to use the currently configured format to
     333                 :            :  *                      determine the plane sizes and \*num_buffers is the total
     334                 :            :  *                      number of buffers that are being allocated. When called
     335                 :            :  *                      from VIDIOC_CREATE_BUFS(), \*num_planes != 0 and it
     336                 :            :  *                      describes the requested number of planes and sizes\[\]
     337                 :            :  *                      contains the requested plane sizes. In this case
     338                 :            :  *                      \*num_buffers are being allocated additionally to
     339                 :            :  *                      q->num_buffers. If either \*num_planes or the requested
     340                 :            :  *                      sizes are invalid callback must return %-EINVAL.
     341                 :            :  * @wait_prepare:       release any locks taken while calling vb2 functions;
     342                 :            :  *                      it is called before an ioctl needs to wait for a new
     343                 :            :  *                      buffer to arrive; required to avoid a deadlock in
     344                 :            :  *                      blocking access type.
     345                 :            :  * @wait_finish:        reacquire all locks released in the previous callback;
     346                 :            :  *                      required to continue operation after sleeping while
     347                 :            :  *                      waiting for a new buffer to arrive.
     348                 :            :  * @buf_out_validate:   called when the output buffer is prepared or queued
     349                 :            :  *                      to a request; drivers can use this to validate
     350                 :            :  *                      userspace-provided information; this is required only
     351                 :            :  *                      for OUTPUT queues.
     352                 :            :  * @buf_init:           called once after allocating a buffer (in MMAP case)
     353                 :            :  *                      or after acquiring a new USERPTR buffer; drivers may
     354                 :            :  *                      perform additional buffer-related initialization;
     355                 :            :  *                      initialization failure (return != 0) will prevent
     356                 :            :  *                      queue setup from completing successfully; optional.
     357                 :            :  * @buf_prepare:        called every time the buffer is queued from userspace
     358                 :            :  *                      and from the VIDIOC_PREPARE_BUF() ioctl; drivers may
     359                 :            :  *                      perform any initialization required before each
     360                 :            :  *                      hardware operation in this callback; drivers can
     361                 :            :  *                      access/modify the buffer here as it is still synced for
     362                 :            :  *                      the CPU; drivers that support VIDIOC_CREATE_BUFS() must
     363                 :            :  *                      also validate the buffer size; if an error is returned,
     364                 :            :  *                      the buffer will not be queued in driver; optional.
     365                 :            :  * @buf_finish:         called before every dequeue of the buffer back to
     366                 :            :  *                      userspace; the buffer is synced for the CPU, so drivers
     367                 :            :  *                      can access/modify the buffer contents; drivers may
     368                 :            :  *                      perform any operations required before userspace
     369                 :            :  *                      accesses the buffer; optional. The buffer state can be
     370                 :            :  *                      one of the following: %DONE and %ERROR occur while
     371                 :            :  *                      streaming is in progress, and the %PREPARED state occurs
     372                 :            :  *                      when the queue has been canceled and all pending
     373                 :            :  *                      buffers are being returned to their default %DEQUEUED
     374                 :            :  *                      state. Typically you only have to do something if the
     375                 :            :  *                      state is %VB2_BUF_STATE_DONE, since in all other cases
     376                 :            :  *                      the buffer contents will be ignored anyway.
     377                 :            :  * @buf_cleanup:        called once before the buffer is freed; drivers may
     378                 :            :  *                      perform any additional cleanup; optional.
     379                 :            :  * @start_streaming:    called once to enter 'streaming' state; the driver may
     380                 :            :  *                      receive buffers with @buf_queue callback
     381                 :            :  *                      before @start_streaming is called; the driver gets the
     382                 :            :  *                      number of already queued buffers in count parameter;
     383                 :            :  *                      driver can return an error if hardware fails, in that
     384                 :            :  *                      case all buffers that have been already given by
     385                 :            :  *                      the @buf_queue callback are to be returned by the driver
     386                 :            :  *                      by calling vb2_buffer_done() with %VB2_BUF_STATE_QUEUED.
     387                 :            :  *                      If you need a minimum number of buffers before you can
     388                 :            :  *                      start streaming, then set
     389                 :            :  *                      &vb2_queue->min_buffers_needed. If that is non-zero
     390                 :            :  *                      then @start_streaming won't be called until at least
     391                 :            :  *                      that many buffers have been queued up by userspace.
     392                 :            :  * @stop_streaming:     called when 'streaming' state must be disabled; driver
     393                 :            :  *                      should stop any DMA transactions or wait until they
     394                 :            :  *                      finish and give back all buffers it got from &buf_queue
     395                 :            :  *                      callback by calling vb2_buffer_done() with either
     396                 :            :  *                      %VB2_BUF_STATE_DONE or %VB2_BUF_STATE_ERROR; may use
     397                 :            :  *                      vb2_wait_for_all_buffers() function
     398                 :            :  * @buf_queue:          passes buffer vb to the driver; driver may start
     399                 :            :  *                      hardware operation on this buffer; driver should give
     400                 :            :  *                      the buffer back by calling vb2_buffer_done() function;
     401                 :            :  *                      it is always called after calling VIDIOC_STREAMON()
     402                 :            :  *                      ioctl; might be called before @start_streaming callback
     403                 :            :  *                      if user pre-queued buffers before calling
     404                 :            :  *                      VIDIOC_STREAMON().
     405                 :            :  * @buf_request_complete: a buffer that was never queued to the driver but is
     406                 :            :  *                      associated with a queued request was canceled.
     407                 :            :  *                      The driver will have to mark associated objects in the
     408                 :            :  *                      request as completed; required if requests are
     409                 :            :  *                      supported.
     410                 :            :  */
     411                 :            : struct vb2_ops {
     412                 :            :         int (*queue_setup)(struct vb2_queue *q,
     413                 :            :                            unsigned int *num_buffers, unsigned int *num_planes,
     414                 :            :                            unsigned int sizes[], struct device *alloc_devs[]);
     415                 :            : 
     416                 :            :         void (*wait_prepare)(struct vb2_queue *q);
     417                 :            :         void (*wait_finish)(struct vb2_queue *q);
     418                 :            : 
     419                 :            :         int (*buf_out_validate)(struct vb2_buffer *vb);
     420                 :            :         int (*buf_init)(struct vb2_buffer *vb);
     421                 :            :         int (*buf_prepare)(struct vb2_buffer *vb);
     422                 :            :         void (*buf_finish)(struct vb2_buffer *vb);
     423                 :            :         void (*buf_cleanup)(struct vb2_buffer *vb);
     424                 :            : 
     425                 :            :         int (*start_streaming)(struct vb2_queue *q, unsigned int count);
     426                 :            :         void (*stop_streaming)(struct vb2_queue *q);
     427                 :            : 
     428                 :            :         void (*buf_queue)(struct vb2_buffer *vb);
     429                 :            : 
     430                 :            :         void (*buf_request_complete)(struct vb2_buffer *vb);
     431                 :            : };
     432                 :            : 
     433                 :            : /**
     434                 :            :  * struct vb2_buf_ops - driver-specific callbacks.
     435                 :            :  *
     436                 :            :  * @verify_planes_array: Verify that a given user space structure contains
     437                 :            :  *                      enough planes for the buffer. This is called
     438                 :            :  *                      for each dequeued buffer.
     439                 :            :  * @init_buffer:        given a &vb2_buffer initialize the extra data after
     440                 :            :  *                      struct vb2_buffer.
     441                 :            :  *                      For V4L2 this is a &struct vb2_v4l2_buffer.
     442                 :            :  * @fill_user_buffer:   given a &vb2_buffer fill in the userspace structure.
     443                 :            :  *                      For V4L2 this is a &struct v4l2_buffer.
     444                 :            :  * @fill_vb2_buffer:    given a userspace structure, fill in the &vb2_buffer.
     445                 :            :  *                      If the userspace structure is invalid, then this op
     446                 :            :  *                      will return an error.
     447                 :            :  * @copy_timestamp:     copy the timestamp from a userspace structure to
     448                 :            :  *                      the &struct vb2_buffer.
     449                 :            :  */
     450                 :            : struct vb2_buf_ops {
     451                 :            :         int (*verify_planes_array)(struct vb2_buffer *vb, const void *pb);
     452                 :            :         void (*init_buffer)(struct vb2_buffer *vb);
     453                 :            :         void (*fill_user_buffer)(struct vb2_buffer *vb, void *pb);
     454                 :            :         int (*fill_vb2_buffer)(struct vb2_buffer *vb, struct vb2_plane *planes);
     455                 :            :         void (*copy_timestamp)(struct vb2_buffer *vb, const void *pb);
     456                 :            : };
     457                 :            : 
     458                 :            : /**
     459                 :            :  * struct vb2_queue - a videobuf queue.
     460                 :            :  *
     461                 :            :  * @type:       private buffer type whose content is defined by the vb2-core
     462                 :            :  *              caller. For example, for V4L2, it should match
     463                 :            :  *              the types defined on &enum v4l2_buf_type.
     464                 :            :  * @io_modes:   supported io methods (see &enum vb2_io_modes).
     465                 :            :  * @alloc_devs: &struct device memory type/allocator-specific per-plane device
     466                 :            :  * @dev:        device to use for the default allocation context if the driver
     467                 :            :  *              doesn't fill in the @alloc_devs array.
     468                 :            :  * @dma_attrs:  DMA attributes to use for the DMA.
     469                 :            :  * @bidirectional: when this flag is set the DMA direction for the buffers of
     470                 :            :  *              this queue will be overridden with %DMA_BIDIRECTIONAL direction.
     471                 :            :  *              This is useful in cases where the hardware (firmware) writes to
     472                 :            :  *              a buffer which is mapped as read (%DMA_TO_DEVICE), or reads from
     473                 :            :  *              buffer which is mapped for write (%DMA_FROM_DEVICE) in order
     474                 :            :  *              to satisfy some internal hardware restrictions or adds a padding
     475                 :            :  *              needed by the processing algorithm. In case the DMA mapping is
     476                 :            :  *              not bidirectional but the hardware (firmware) trying to access
     477                 :            :  *              the buffer (in the opposite direction) this could lead to an
     478                 :            :  *              IOMMU protection faults.
     479                 :            :  * @fileio_read_once:           report EOF after reading the first buffer
     480                 :            :  * @fileio_write_immediately:   queue buffer after each write() call
     481                 :            :  * @allow_zero_bytesused:       allow bytesused == 0 to be passed to the driver
     482                 :            :  * @quirk_poll_must_check_waiting_for_buffers: Return %EPOLLERR at poll when QBUF
     483                 :            :  *              has not been called. This is a vb1 idiom that has been adopted
     484                 :            :  *              also by vb2.
     485                 :            :  * @supports_requests: this queue supports the Request API.
     486                 :            :  * @requires_requests: this queue requires the Request API. If this is set to 1,
     487                 :            :  *              then supports_requests must be set to 1 as well.
     488                 :            :  * @uses_qbuf:  qbuf was used directly for this queue. Set to 1 the first
     489                 :            :  *              time this is called. Set to 0 when the queue is canceled.
     490                 :            :  *              If this is 1, then you cannot queue buffers from a request.
     491                 :            :  * @uses_requests: requests are used for this queue. Set to 1 the first time
     492                 :            :  *              a request is queued. Set to 0 when the queue is canceled.
     493                 :            :  *              If this is 1, then you cannot queue buffers directly.
     494                 :            :  * @lock:       pointer to a mutex that protects the &struct vb2_queue. The
     495                 :            :  *              driver can set this to a mutex to let the v4l2 core serialize
     496                 :            :  *              the queuing ioctls. If the driver wants to handle locking
     497                 :            :  *              itself, then this should be set to NULL. This lock is not used
     498                 :            :  *              by the videobuf2 core API.
     499                 :            :  * @owner:      The filehandle that 'owns' the buffers, i.e. the filehandle
     500                 :            :  *              that called reqbufs, create_buffers or started fileio.
     501                 :            :  *              This field is not used by the videobuf2 core API, but it allows
     502                 :            :  *              drivers to easily associate an owner filehandle with the queue.
     503                 :            :  * @ops:        driver-specific callbacks
     504                 :            :  * @mem_ops:    memory allocator specific callbacks
     505                 :            :  * @buf_ops:    callbacks to deliver buffer information.
     506                 :            :  *              between user-space and kernel-space.
     507                 :            :  * @drv_priv:   driver private data.
     508                 :            :  * @subsystem_flags: Flags specific to the subsystem (V4L2/DVB/etc.). Not used
     509                 :            :  *              by the vb2 core.
     510                 :            :  * @buf_struct_size: size of the driver-specific buffer structure;
     511                 :            :  *              "0" indicates the driver doesn't want to use a custom buffer
     512                 :            :  *              structure type. for example, ``sizeof(struct vb2_v4l2_buffer)``
     513                 :            :  *              will be used for v4l2.
     514                 :            :  * @timestamp_flags: Timestamp flags; ``V4L2_BUF_FLAG_TIMESTAMP_*`` and
     515                 :            :  *              ``V4L2_BUF_FLAG_TSTAMP_SRC_*``
     516                 :            :  * @gfp_flags:  additional gfp flags used when allocating the buffers.
     517                 :            :  *              Typically this is 0, but it may be e.g. %GFP_DMA or %__GFP_DMA32
     518                 :            :  *              to force the buffer allocation to a specific memory zone.
     519                 :            :  * @min_buffers_needed: the minimum number of buffers needed before
     520                 :            :  *              @start_streaming can be called. Used when a DMA engine
     521                 :            :  *              cannot be started unless at least this number of buffers
     522                 :            :  *              have been queued into the driver.
     523                 :            :  */
     524                 :            : /*
     525                 :            :  * Private elements (won't appear at the uAPI book):
     526                 :            :  * @mmap_lock:  private mutex used when buffers are allocated/freed/mmapped
     527                 :            :  * @memory:     current memory type used
     528                 :            :  * @dma_dir:    DMA mapping direction.
     529                 :            :  * @bufs:       videobuf buffer structures
     530                 :            :  * @num_buffers: number of allocated/used buffers
     531                 :            :  * @queued_list: list of buffers currently queued from userspace
     532                 :            :  * @queued_count: number of buffers queued and ready for streaming.
     533                 :            :  * @owned_by_drv_count: number of buffers owned by the driver
     534                 :            :  * @done_list:  list of buffers ready to be dequeued to userspace
     535                 :            :  * @done_lock:  lock to protect done_list list
     536                 :            :  * @done_wq:    waitqueue for processes waiting for buffers ready to be dequeued
     537                 :            :  * @streaming:  current streaming state
     538                 :            :  * @start_streaming_called: @start_streaming was called successfully and we
     539                 :            :  *              started streaming.
     540                 :            :  * @error:      a fatal error occurred on the queue
     541                 :            :  * @waiting_for_buffers: used in poll() to check if vb2 is still waiting for
     542                 :            :  *              buffers. Only set for capture queues if qbuf has not yet been
     543                 :            :  *              called since poll() needs to return %EPOLLERR in that situation.
     544                 :            :  * @is_multiplanar: set if buffer type is multiplanar
     545                 :            :  * @is_output:  set if buffer type is output
     546                 :            :  * @copy_timestamp: set if vb2-core should set timestamps
     547                 :            :  * @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the
     548                 :            :  *              last decoded buffer was already dequeued. Set for capture queues
     549                 :            :  *              when a buffer with the %V4L2_BUF_FLAG_LAST is dequeued.
     550                 :            :  * @fileio:     file io emulator internal data, used only if emulator is active
     551                 :            :  * @threadio:   thread io internal data, used only if thread is active
     552                 :            :  */
     553                 :            : struct vb2_queue {
     554                 :            :         unsigned int                    type;
     555                 :            :         unsigned int                    io_modes;
     556                 :            :         struct device                   *dev;
     557                 :            :         unsigned long                   dma_attrs;
     558                 :            :         unsigned                        bidirectional:1;
     559                 :            :         unsigned                        fileio_read_once:1;
     560                 :            :         unsigned                        fileio_write_immediately:1;
     561                 :            :         unsigned                        allow_zero_bytesused:1;
     562                 :            :         unsigned                   quirk_poll_must_check_waiting_for_buffers:1;
     563                 :            :         unsigned                        supports_requests:1;
     564                 :            :         unsigned                        requires_requests:1;
     565                 :            :         unsigned                        uses_qbuf:1;
     566                 :            :         unsigned                        uses_requests:1;
     567                 :            : 
     568                 :            :         struct mutex                    *lock;
     569                 :            :         void                            *owner;
     570                 :            : 
     571                 :            :         const struct vb2_ops            *ops;
     572                 :            :         const struct vb2_mem_ops        *mem_ops;
     573                 :            :         const struct vb2_buf_ops        *buf_ops;
     574                 :            : 
     575                 :            :         void                            *drv_priv;
     576                 :            :         u32                             subsystem_flags;
     577                 :            :         unsigned int                    buf_struct_size;
     578                 :            :         u32                             timestamp_flags;
     579                 :            :         gfp_t                           gfp_flags;
     580                 :            :         u32                             min_buffers_needed;
     581                 :            : 
     582                 :            :         struct device                   *alloc_devs[VB2_MAX_PLANES];
     583                 :            : 
     584                 :            :         /* private: internal use only */
     585                 :            :         struct mutex                    mmap_lock;
     586                 :            :         unsigned int                    memory;
     587                 :            :         enum dma_data_direction         dma_dir;
     588                 :            :         struct vb2_buffer               *bufs[VB2_MAX_FRAME];
     589                 :            :         unsigned int                    num_buffers;
     590                 :            : 
     591                 :            :         struct list_head                queued_list;
     592                 :            :         unsigned int                    queued_count;
     593                 :            : 
     594                 :            :         atomic_t                        owned_by_drv_count;
     595                 :            :         struct list_head                done_list;
     596                 :            :         spinlock_t                      done_lock;
     597                 :            :         wait_queue_head_t               done_wq;
     598                 :            : 
     599                 :            :         unsigned int                    streaming:1;
     600                 :            :         unsigned int                    start_streaming_called:1;
     601                 :            :         unsigned int                    error:1;
     602                 :            :         unsigned int                    waiting_for_buffers:1;
     603                 :            :         unsigned int                    waiting_in_dqbuf:1;
     604                 :            :         unsigned int                    is_multiplanar:1;
     605                 :            :         unsigned int                    is_output:1;
     606                 :            :         unsigned int                    copy_timestamp:1;
     607                 :            :         unsigned int                    last_buffer_dequeued:1;
     608                 :            : 
     609                 :            :         struct vb2_fileio_data          *fileio;
     610                 :            :         struct vb2_threadio_data        *threadio;
     611                 :            : 
     612                 :            : #ifdef CONFIG_VIDEO_ADV_DEBUG
     613                 :            :         /*
     614                 :            :          * Counters for how often these queue-related ops are
     615                 :            :          * called. Used to check for unbalanced ops.
     616                 :            :          */
     617                 :            :         u32                             cnt_queue_setup;
     618                 :            :         u32                             cnt_wait_prepare;
     619                 :            :         u32                             cnt_wait_finish;
     620                 :            :         u32                             cnt_start_streaming;
     621                 :            :         u32                             cnt_stop_streaming;
     622                 :            : #endif
     623                 :            : };
     624                 :            : 
     625                 :            : /**
     626                 :            :  * vb2_plane_vaddr() - Return a kernel virtual address of a given plane.
     627                 :            :  * @vb:         pointer to &struct vb2_buffer to which the plane in
     628                 :            :  *              question belongs to.
     629                 :            :  * @plane_no:   plane number for which the address is to be returned.
     630                 :            :  *
     631                 :            :  * This function returns a kernel virtual address of a given plane if
     632                 :            :  * such a mapping exist, NULL otherwise.
     633                 :            :  */
     634                 :            : void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no);
     635                 :            : 
     636                 :            : /**
     637                 :            :  * vb2_plane_cookie() - Return allocator specific cookie for the given plane.
     638                 :            :  * @vb:         pointer to &struct vb2_buffer to which the plane in
     639                 :            :  *              question belongs to.
     640                 :            :  * @plane_no:   plane number for which the cookie is to be returned.
     641                 :            :  *
     642                 :            :  * This function returns an allocator specific cookie for a given plane if
     643                 :            :  * available, NULL otherwise. The allocator should provide some simple static
     644                 :            :  * inline function, which would convert this cookie to the allocator specific
     645                 :            :  * type that can be used directly by the driver to access the buffer. This can
     646                 :            :  * be for example physical address, pointer to scatter list or IOMMU mapping.
     647                 :            :  */
     648                 :            : void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no);
     649                 :            : 
     650                 :            : /**
     651                 :            :  * vb2_buffer_done() - inform videobuf that an operation on a buffer
     652                 :            :  *      is finished.
     653                 :            :  * @vb:         pointer to &struct vb2_buffer to be used.
     654                 :            :  * @state:      state of the buffer, as defined by &enum vb2_buffer_state.
     655                 :            :  *              Either %VB2_BUF_STATE_DONE if the operation finished
     656                 :            :  *              successfully, %VB2_BUF_STATE_ERROR if the operation finished
     657                 :            :  *              with an error or %VB2_BUF_STATE_QUEUED.
     658                 :            :  *
     659                 :            :  * This function should be called by the driver after a hardware operation on
     660                 :            :  * a buffer is finished and the buffer may be returned to userspace. The driver
     661                 :            :  * cannot use this buffer anymore until it is queued back to it by videobuf
     662                 :            :  * by the means of &vb2_ops->buf_queue callback. Only buffers previously queued
     663                 :            :  * to the driver by &vb2_ops->buf_queue can be passed to this function.
     664                 :            :  *
     665                 :            :  * While streaming a buffer can only be returned in state DONE or ERROR.
     666                 :            :  * The &vb2_ops->start_streaming op can also return them in case the DMA engine
     667                 :            :  * cannot be started for some reason. In that case the buffers should be
     668                 :            :  * returned with state QUEUED to put them back into the queue.
     669                 :            :  */
     670                 :            : void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state);
     671                 :            : 
     672                 :            : /**
     673                 :            :  * vb2_discard_done() - discard all buffers marked as DONE.
     674                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
     675                 :            :  *
     676                 :            :  * This function is intended to be used with suspend/resume operations. It
     677                 :            :  * discards all 'done' buffers as they would be too old to be requested after
     678                 :            :  * resume.
     679                 :            :  *
     680                 :            :  * Drivers must stop the hardware and synchronize with interrupt handlers and/or
     681                 :            :  * delayed works before calling this function to make sure no buffer will be
     682                 :            :  * touched by the driver and/or hardware.
     683                 :            :  */
     684                 :            : void vb2_discard_done(struct vb2_queue *q);
     685                 :            : 
     686                 :            : /**
     687                 :            :  * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2.
     688                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
     689                 :            :  *
     690                 :            :  * This function will wait until all buffers that have been given to the driver
     691                 :            :  * by &vb2_ops->buf_queue are given back to vb2 with vb2_buffer_done(). It
     692                 :            :  * doesn't call &vb2_ops->wait_prepare/&vb2_ops->wait_finish pair.
     693                 :            :  * It is intended to be called with all locks taken, for example from
     694                 :            :  * &vb2_ops->stop_streaming callback.
     695                 :            :  */
     696                 :            : int vb2_wait_for_all_buffers(struct vb2_queue *q);
     697                 :            : 
     698                 :            : /**
     699                 :            :  * vb2_core_querybuf() - query video buffer information.
     700                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
     701                 :            :  * @index:      id number of the buffer.
     702                 :            :  * @pb:         buffer struct passed from userspace.
     703                 :            :  *
     704                 :            :  * Videobuf2 core helper to implement VIDIOC_QUERYBUF() operation. It is called
     705                 :            :  * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
     706                 :            :  *
     707                 :            :  * The passed buffer should have been verified.
     708                 :            :  *
     709                 :            :  * This function fills the relevant information for the userspace.
     710                 :            :  *
     711                 :            :  * Return: returns zero on success; an error code otherwise.
     712                 :            :  */
     713                 :            : void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb);
     714                 :            : 
     715                 :            : /**
     716                 :            :  * vb2_core_reqbufs() - Initiate streaming.
     717                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
     718                 :            :  * @memory:     memory type, as defined by &enum vb2_memory.
     719                 :            :  * @count:      requested buffer count.
     720                 :            :  *
     721                 :            :  * Videobuf2 core helper to implement VIDIOC_REQBUF() operation. It is called
     722                 :            :  * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
     723                 :            :  *
     724                 :            :  * This function:
     725                 :            :  *
     726                 :            :  * #) verifies streaming parameters passed from the userspace;
     727                 :            :  * #) sets up the queue;
     728                 :            :  * #) negotiates number of buffers and planes per buffer with the driver
     729                 :            :  *    to be used during streaming;
     730                 :            :  * #) allocates internal buffer structures (&struct vb2_buffer), according to
     731                 :            :  *    the agreed parameters;
     732                 :            :  * #) for MMAP memory type, allocates actual video memory, using the
     733                 :            :  *    memory handling/allocation routines provided during queue initialization.
     734                 :            :  *
     735                 :            :  * If req->count is 0, all the memory will be freed instead.
     736                 :            :  *
     737                 :            :  * If the queue has been allocated previously by a previous vb2_core_reqbufs()
     738                 :            :  * call and the queue is not busy, memory will be reallocated.
     739                 :            :  *
     740                 :            :  * Return: returns zero on success; an error code otherwise.
     741                 :            :  */
     742                 :            : int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
     743                 :            :                 unsigned int *count);
     744                 :            : 
     745                 :            : /**
     746                 :            :  * vb2_core_create_bufs() - Allocate buffers and any required auxiliary structs
     747                 :            :  * @q: pointer to &struct vb2_queue with videobuf2 queue.
     748                 :            :  * @memory: memory type, as defined by &enum vb2_memory.
     749                 :            :  * @count: requested buffer count.
     750                 :            :  * @requested_planes: number of planes requested.
     751                 :            :  * @requested_sizes: array with the size of the planes.
     752                 :            :  *
     753                 :            :  * Videobuf2 core helper to implement VIDIOC_CREATE_BUFS() operation. It is
     754                 :            :  * called internally by VB2 by an API-specific handler, like
     755                 :            :  * ``videobuf2-v4l2.h``.
     756                 :            :  *
     757                 :            :  * This function:
     758                 :            :  *
     759                 :            :  * #) verifies parameter sanity;
     760                 :            :  * #) calls the &vb2_ops->queue_setup queue operation;
     761                 :            :  * #) performs any necessary memory allocations.
     762                 :            :  *
     763                 :            :  * Return: returns zero on success; an error code otherwise.
     764                 :            :  */
     765                 :            : int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
     766                 :            :                          unsigned int *count, unsigned int requested_planes,
     767                 :            :                          const unsigned int requested_sizes[]);
     768                 :            : 
     769                 :            : /**
     770                 :            :  * vb2_core_prepare_buf() - Pass ownership of a buffer from userspace
     771                 :            :  *                      to the kernel.
     772                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
     773                 :            :  * @index:      id number of the buffer.
     774                 :            :  * @pb:         buffer structure passed from userspace to
     775                 :            :  *              &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver.
     776                 :            :  *
     777                 :            :  * Videobuf2 core helper to implement VIDIOC_PREPARE_BUF() operation. It is
     778                 :            :  * called internally by VB2 by an API-specific handler, like
     779                 :            :  * ``videobuf2-v4l2.h``.
     780                 :            :  *
     781                 :            :  * The passed buffer should have been verified.
     782                 :            :  *
     783                 :            :  * This function calls vb2_ops->buf_prepare callback in the driver
     784                 :            :  * (if provided), in which driver-specific buffer initialization can
     785                 :            :  * be performed.
     786                 :            :  *
     787                 :            :  * Return: returns zero on success; an error code otherwise.
     788                 :            :  */
     789                 :            : int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb);
     790                 :            : 
     791                 :            : /**
     792                 :            :  * vb2_core_qbuf() - Queue a buffer from userspace
     793                 :            :  *
     794                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
     795                 :            :  * @index:      id number of the buffer
     796                 :            :  * @pb:         buffer structure passed from userspace to
     797                 :            :  *              v4l2_ioctl_ops->vidioc_qbuf handler in driver
     798                 :            :  * @req:        pointer to &struct media_request, may be NULL.
     799                 :            :  *
     800                 :            :  * Videobuf2 core helper to implement VIDIOC_QBUF() operation. It is called
     801                 :            :  * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
     802                 :            :  *
     803                 :            :  * This function:
     804                 :            :  *
     805                 :            :  * #) If @req is non-NULL, then the buffer will be bound to this
     806                 :            :  *    media request and it returns. The buffer will be prepared and
     807                 :            :  *    queued to the driver (i.e. the next two steps) when the request
     808                 :            :  *    itself is queued.
     809                 :            :  * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver
     810                 :            :  *    (if provided), in which driver-specific buffer initialization can
     811                 :            :  *    be performed;
     812                 :            :  * #) if streaming is on, queues the buffer in driver by the means of
     813                 :            :  *    &vb2_ops->buf_queue callback for processing.
     814                 :            :  *
     815                 :            :  * Return: returns zero on success; an error code otherwise.
     816                 :            :  */
     817                 :            : int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb,
     818                 :            :                   struct media_request *req);
     819                 :            : 
     820                 :            : /**
     821                 :            :  * vb2_core_dqbuf() - Dequeue a buffer to the userspace
     822                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue
     823                 :            :  * @pindex:     pointer to the buffer index. May be NULL
     824                 :            :  * @pb:         buffer structure passed from userspace to
     825                 :            :  *              v4l2_ioctl_ops->vidioc_dqbuf handler in driver.
     826                 :            :  * @nonblocking: if true, this call will not sleep waiting for a buffer if no
     827                 :            :  *               buffers ready for dequeuing are present. Normally the driver
     828                 :            :  *               would be passing (file->f_flags & O_NONBLOCK) here.
     829                 :            :  *
     830                 :            :  * Videobuf2 core helper to implement VIDIOC_DQBUF() operation. It is called
     831                 :            :  * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
     832                 :            :  *
     833                 :            :  * This function:
     834                 :            :  *
     835                 :            :  * #) calls buf_finish callback in the driver (if provided), in which
     836                 :            :  *    driver can perform any additional operations that may be required before
     837                 :            :  *    returning the buffer to userspace, such as cache sync,
     838                 :            :  * #) the buffer struct members are filled with relevant information for
     839                 :            :  *    the userspace.
     840                 :            :  *
     841                 :            :  * Return: returns zero on success; an error code otherwise.
     842                 :            :  */
     843                 :            : int vb2_core_dqbuf(struct vb2_queue *q, unsigned int *pindex, void *pb,
     844                 :            :                    bool nonblocking);
     845                 :            : 
     846                 :            : /**
     847                 :            :  * vb2_core_streamon() - Implements VB2 stream ON logic
     848                 :            :  *
     849                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue
     850                 :            :  * @type:       type of the queue to be started.
     851                 :            :  *              For V4L2, this is defined by &enum v4l2_buf_type type.
     852                 :            :  *
     853                 :            :  * Videobuf2 core helper to implement VIDIOC_STREAMON() operation. It is called
     854                 :            :  * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
     855                 :            :  *
     856                 :            :  * Return: returns zero on success; an error code otherwise.
     857                 :            :  */
     858                 :            : int vb2_core_streamon(struct vb2_queue *q, unsigned int type);
     859                 :            : 
     860                 :            : /**
     861                 :            :  * vb2_core_streamoff() - Implements VB2 stream OFF logic
     862                 :            :  *
     863                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue
     864                 :            :  * @type:       type of the queue to be started.
     865                 :            :  *              For V4L2, this is defined by &enum v4l2_buf_type type.
     866                 :            :  *
     867                 :            :  * Videobuf2 core helper to implement VIDIOC_STREAMOFF() operation. It is
     868                 :            :  * called internally by VB2 by an API-specific handler, like
     869                 :            :  * ``videobuf2-v4l2.h``.
     870                 :            :  *
     871                 :            :  * Return: returns zero on success; an error code otherwise.
     872                 :            :  */
     873                 :            : int vb2_core_streamoff(struct vb2_queue *q, unsigned int type);
     874                 :            : 
     875                 :            : /**
     876                 :            :  * vb2_core_expbuf_dmabuf() - Export a buffer as a dma_buf structure
     877                 :            :  * @q:         videobuf2 queue
     878                 :            :  * @type:      buffer type
     879                 :            :  * @index:     id number of the buffer
     880                 :            :  * @plane:     index of the plane to be exported, 0 for single plane queues
     881                 :            :  * @flags:     flags for newly created file, currently only O_CLOEXEC is
     882                 :            :  *             supported, refer to manual of open syscall for more details
     883                 :            :  * @dmabuf:    Returns the dmabuf pointer
     884                 :            :  *
     885                 :            :  */
     886                 :            : int vb2_core_expbuf_dmabuf(struct vb2_queue *q, unsigned int type,
     887                 :            :                            unsigned int index, unsigned int plane,
     888                 :            :                            unsigned int flags, struct dma_buf **dmabuf);
     889                 :            : 
     890                 :            : /**
     891                 :            :  * vb2_core_expbuf() - Export a buffer as a file descriptor.
     892                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
     893                 :            :  * @fd:         pointer to the file descriptor associated with DMABUF
     894                 :            :  *              (set by driver).
     895                 :            :  * @type:       buffer type.
     896                 :            :  * @index:      id number of the buffer.
     897                 :            :  * @plane:      index of the plane to be exported, 0 for single plane queues
     898                 :            :  * @flags:      file flags for newly created file, as defined at
     899                 :            :  *              include/uapi/asm-generic/fcntl.h.
     900                 :            :  *              Currently, the only used flag is %O_CLOEXEC.
     901                 :            :  *              is supported, refer to manual of open syscall for more details.
     902                 :            :  *
     903                 :            :  *
     904                 :            :  * Videobuf2 core helper to implement VIDIOC_EXPBUF() operation. It is called
     905                 :            :  * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
     906                 :            :  *
     907                 :            :  * Return: returns zero on success; an error code otherwise.
     908                 :            :  */
     909                 :            : int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type,
     910                 :            :                 unsigned int index, unsigned int plane, unsigned int flags);
     911                 :            : 
     912                 :            : /**
     913                 :            :  * vb2_core_queue_init() - initialize a videobuf2 queue
     914                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
     915                 :            :  *              This structure should be allocated in driver
     916                 :            :  *
     917                 :            :  * The &vb2_queue structure should be allocated by the driver. The driver is
     918                 :            :  * responsible of clearing it's content and setting initial values for some
     919                 :            :  * required entries before calling this function.
     920                 :            :  *
     921                 :            :  * .. note::
     922                 :            :  *
     923                 :            :  *    The following fields at @q should be set before calling this function:
     924                 :            :  *    &vb2_queue->ops, &vb2_queue->mem_ops, &vb2_queue->type.
     925                 :            :  */
     926                 :            : int vb2_core_queue_init(struct vb2_queue *q);
     927                 :            : 
     928                 :            : /**
     929                 :            :  * vb2_core_queue_release() - stop streaming, release the queue and free memory
     930                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
     931                 :            :  *
     932                 :            :  * This function stops streaming and performs necessary clean ups, including
     933                 :            :  * freeing video buffer memory. The driver is responsible for freeing
     934                 :            :  * the &struct vb2_queue itself.
     935                 :            :  */
     936                 :            : void vb2_core_queue_release(struct vb2_queue *q);
     937                 :            : 
     938                 :            : /**
     939                 :            :  * vb2_queue_error() - signal a fatal error on the queue
     940                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
     941                 :            :  *
     942                 :            :  * Flag that a fatal unrecoverable error has occurred and wake up all processes
     943                 :            :  * waiting on the queue. Polling will now set %EPOLLERR and queuing and dequeuing
     944                 :            :  * buffers will return %-EIO.
     945                 :            :  *
     946                 :            :  * The error flag will be cleared when canceling the queue, either from
     947                 :            :  * vb2_streamoff() or vb2_queue_release(). Drivers should thus not call this
     948                 :            :  * function before starting the stream, otherwise the error flag will remain set
     949                 :            :  * until the queue is released when closing the device node.
     950                 :            :  */
     951                 :            : void vb2_queue_error(struct vb2_queue *q);
     952                 :            : 
     953                 :            : /**
     954                 :            :  * vb2_mmap() - map video buffers into application address space.
     955                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
     956                 :            :  * @vma:        pointer to &struct vm_area_struct with the vma passed
     957                 :            :  *              to the mmap file operation handler in the driver.
     958                 :            :  *
     959                 :            :  * Should be called from mmap file operation handler of a driver.
     960                 :            :  * This function maps one plane of one of the available video buffers to
     961                 :            :  * userspace. To map whole video memory allocated on reqbufs, this function
     962                 :            :  * has to be called once per each plane per each buffer previously allocated.
     963                 :            :  *
     964                 :            :  * When the userspace application calls mmap, it passes to it an offset returned
     965                 :            :  * to it earlier by the means of &v4l2_ioctl_ops->vidioc_querybuf handler.
     966                 :            :  * That offset acts as a "cookie", which is then used to identify the plane
     967                 :            :  * to be mapped.
     968                 :            :  *
     969                 :            :  * This function finds a plane with a matching offset and a mapping is performed
     970                 :            :  * by the means of a provided memory operation.
     971                 :            :  *
     972                 :            :  * The return values from this function are intended to be directly returned
     973                 :            :  * from the mmap handler in driver.
     974                 :            :  */
     975                 :            : int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma);
     976                 :            : 
     977                 :            : #ifndef CONFIG_MMU
     978                 :            : /**
     979                 :            :  * vb2_get_unmapped_area - map video buffers into application address space.
     980                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
     981                 :            :  * @addr:       memory address.
     982                 :            :  * @len:        buffer size.
     983                 :            :  * @pgoff:      page offset.
     984                 :            :  * @flags:      memory flags.
     985                 :            :  *
     986                 :            :  * This function is used in noMMU platforms to propose address mapping
     987                 :            :  * for a given buffer. It's intended to be used as a handler for the
     988                 :            :  * &file_operations->get_unmapped_area operation.
     989                 :            :  *
     990                 :            :  * This is called by the mmap() syscall routines will call this
     991                 :            :  * to get a proposed address for the mapping, when ``!CONFIG_MMU``.
     992                 :            :  */
     993                 :            : unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
     994                 :            :                                     unsigned long addr,
     995                 :            :                                     unsigned long len,
     996                 :            :                                     unsigned long pgoff,
     997                 :            :                                     unsigned long flags);
     998                 :            : #endif
     999                 :            : 
    1000                 :            : /**
    1001                 :            :  * vb2_core_poll() - implements poll syscall() logic.
    1002                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
    1003                 :            :  * @file:       &struct file argument passed to the poll
    1004                 :            :  *              file operation handler.
    1005                 :            :  * @wait:       &poll_table wait argument passed to the poll
    1006                 :            :  *              file operation handler.
    1007                 :            :  *
    1008                 :            :  * This function implements poll file operation handler for a driver.
    1009                 :            :  * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
    1010                 :            :  * be informed that the file descriptor of a video device is available for
    1011                 :            :  * reading.
    1012                 :            :  * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
    1013                 :            :  * will be reported as available for writing.
    1014                 :            :  *
    1015                 :            :  * The return values from this function are intended to be directly returned
    1016                 :            :  * from poll handler in driver.
    1017                 :            :  */
    1018                 :            : __poll_t vb2_core_poll(struct vb2_queue *q, struct file *file,
    1019                 :            :                            poll_table *wait);
    1020                 :            : 
    1021                 :            : /**
    1022                 :            :  * vb2_read() - implements read() syscall logic.
    1023                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
    1024                 :            :  * @data:       pointed to target userspace buffer
    1025                 :            :  * @count:      number of bytes to read
    1026                 :            :  * @ppos:       file handle position tracking pointer
    1027                 :            :  * @nonblock:   mode selector (1 means blocking calls, 0 means nonblocking)
    1028                 :            :  */
    1029                 :            : size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
    1030                 :            :                 loff_t *ppos, int nonblock);
    1031                 :            : /**
    1032                 :            :  * vb2_read() - implements write() syscall logic.
    1033                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
    1034                 :            :  * @data:       pointed to target userspace buffer
    1035                 :            :  * @count:      number of bytes to write
    1036                 :            :  * @ppos:       file handle position tracking pointer
    1037                 :            :  * @nonblock:   mode selector (1 means blocking calls, 0 means nonblocking)
    1038                 :            :  */
    1039                 :            : size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count,
    1040                 :            :                 loff_t *ppos, int nonblock);
    1041                 :            : 
    1042                 :            : /**
    1043                 :            :  * typedef vb2_thread_fnc - callback function for use with vb2_thread.
    1044                 :            :  *
    1045                 :            :  * @vb: pointer to struct &vb2_buffer.
    1046                 :            :  * @priv: pointer to a private data.
    1047                 :            :  *
    1048                 :            :  * This is called whenever a buffer is dequeued in the thread.
    1049                 :            :  */
    1050                 :            : typedef int (*vb2_thread_fnc)(struct vb2_buffer *vb, void *priv);
    1051                 :            : 
    1052                 :            : /**
    1053                 :            :  * vb2_thread_start() - start a thread for the given queue.
    1054                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
    1055                 :            :  * @fnc:        &vb2_thread_fnc callback function.
    1056                 :            :  * @priv:       priv pointer passed to the callback function.
    1057                 :            :  * @thread_name:the name of the thread. This will be prefixed with "vb2-".
    1058                 :            :  *
    1059                 :            :  * This starts a thread that will queue and dequeue until an error occurs
    1060                 :            :  * or vb2_thread_stop() is called.
    1061                 :            :  *
    1062                 :            :  * .. attention::
    1063                 :            :  *
    1064                 :            :  *   This function should not be used for anything else but the videobuf2-dvb
    1065                 :            :  *   support. If you think you have another good use-case for this, then please
    1066                 :            :  *   contact the linux-media mailing list first.
    1067                 :            :  */
    1068                 :            : int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
    1069                 :            :                      const char *thread_name);
    1070                 :            : 
    1071                 :            : /**
    1072                 :            :  * vb2_thread_stop() - stop the thread for the given queue.
    1073                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
    1074                 :            :  */
    1075                 :            : int vb2_thread_stop(struct vb2_queue *q);
    1076                 :            : 
    1077                 :            : /**
    1078                 :            :  * vb2_is_streaming() - return streaming status of the queue.
    1079                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
    1080                 :            :  */
    1081                 :            : static inline bool vb2_is_streaming(struct vb2_queue *q)
    1082                 :            : {
    1083                 :          0 :         return q->streaming;
    1084                 :            : }
    1085                 :            : 
    1086                 :            : /**
    1087                 :            :  * vb2_fileio_is_active() - return true if fileio is active.
    1088                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
    1089                 :            :  *
    1090                 :            :  * This returns true if read() or write() is used to stream the data
    1091                 :            :  * as opposed to stream I/O. This is almost never an important distinction,
    1092                 :            :  * except in rare cases. One such case is that using read() or write() to
    1093                 :            :  * stream a format using %V4L2_FIELD_ALTERNATE is not allowed since there
    1094                 :            :  * is no way you can pass the field information of each buffer to/from
    1095                 :            :  * userspace. A driver that supports this field format should check for
    1096                 :            :  * this in the &vb2_ops->queue_setup op and reject it if this function returns
    1097                 :            :  * true.
    1098                 :            :  */
    1099                 :            : static inline bool vb2_fileio_is_active(struct vb2_queue *q)
    1100                 :            : {
    1101                 :          0 :         return q->fileio;
    1102                 :            : }
    1103                 :            : 
    1104                 :            : /**
    1105                 :            :  * vb2_is_busy() - return busy status of the queue.
    1106                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
    1107                 :            :  *
    1108                 :            :  * This function checks if queue has any buffers allocated.
    1109                 :            :  */
    1110                 :            : static inline bool vb2_is_busy(struct vb2_queue *q)
    1111                 :            : {
    1112                 :          0 :         return (q->num_buffers > 0);
    1113                 :            : }
    1114                 :            : 
    1115                 :            : /**
    1116                 :            :  * vb2_get_drv_priv() - return driver private data associated with the queue.
    1117                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
    1118                 :            :  */
    1119                 :            : static inline void *vb2_get_drv_priv(struct vb2_queue *q)
    1120                 :            : {
    1121                 :          0 :         return q->drv_priv;
    1122                 :            : }
    1123                 :            : 
    1124                 :            : /**
    1125                 :            :  * vb2_set_plane_payload() - set bytesused for the plane @plane_no.
    1126                 :            :  * @vb:         pointer to &struct vb2_buffer to which the plane in
    1127                 :            :  *              question belongs to.
    1128                 :            :  * @plane_no:   plane number for which payload should be set.
    1129                 :            :  * @size:       payload in bytes.
    1130                 :            :  */
    1131                 :            : static inline void vb2_set_plane_payload(struct vb2_buffer *vb,
    1132                 :            :                                  unsigned int plane_no, unsigned long size)
    1133                 :            : {
    1134                 :          0 :         if (plane_no < vb->num_planes)
    1135                 :          0 :                 vb->planes[plane_no].bytesused = size;
    1136                 :            : }
    1137                 :            : 
    1138                 :            : /**
    1139                 :            :  * vb2_get_plane_payload() - get bytesused for the plane plane_no
    1140                 :            :  * @vb:         pointer to &struct vb2_buffer to which the plane in
    1141                 :            :  *              question belongs to.
    1142                 :            :  * @plane_no:   plane number for which payload should be set.
    1143                 :            :  */
    1144                 :            : static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb,
    1145                 :            :                                  unsigned int plane_no)
    1146                 :            : {
    1147                 :          0 :         if (plane_no < vb->num_planes)
    1148                 :          0 :                 return vb->planes[plane_no].bytesused;
    1149                 :            :         return 0;
    1150                 :            : }
    1151                 :            : 
    1152                 :            : /**
    1153                 :            :  * vb2_plane_size() - return plane size in bytes.
    1154                 :            :  * @vb:         pointer to &struct vb2_buffer to which the plane in
    1155                 :            :  *              question belongs to.
    1156                 :            :  * @plane_no:   plane number for which size should be returned.
    1157                 :            :  */
    1158                 :            : static inline unsigned long
    1159                 :            : vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no)
    1160                 :            : {
    1161                 :          0 :         if (plane_no < vb->num_planes)
    1162                 :          0 :                 return vb->planes[plane_no].length;
    1163                 :            :         return 0;
    1164                 :            : }
    1165                 :            : 
    1166                 :            : /**
    1167                 :            :  * vb2_start_streaming_called() - return streaming status of driver.
    1168                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
    1169                 :            :  */
    1170                 :            : static inline bool vb2_start_streaming_called(struct vb2_queue *q)
    1171                 :            : {
    1172                 :            :         return q->start_streaming_called;
    1173                 :            : }
    1174                 :            : 
    1175                 :            : /**
    1176                 :            :  * vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue.
    1177                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
    1178                 :            :  */
    1179                 :            : static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q)
    1180                 :            : {
    1181                 :            :         q->last_buffer_dequeued = false;
    1182                 :            : }
    1183                 :            : 
    1184                 :            : /**
    1185                 :            :  * vb2_get_buffer() - get a buffer from a queue
    1186                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
    1187                 :            :  * @index:      buffer index
    1188                 :            :  *
    1189                 :            :  * This function obtains a buffer from a queue, by its index.
    1190                 :            :  * Keep in mind that there is no refcounting involved in this
    1191                 :            :  * operation, so the buffer lifetime should be taken into
    1192                 :            :  * consideration.
    1193                 :            :  */
    1194                 :            : static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q,
    1195                 :            :                                                 unsigned int index)
    1196                 :            : {
    1197                 :            :         if (index < q->num_buffers)
    1198                 :            :                 return q->bufs[index];
    1199                 :            :         return NULL;
    1200                 :            : }
    1201                 :            : 
    1202                 :            : /*
    1203                 :            :  * The following functions are not part of the vb2 core API, but are useful
    1204                 :            :  * functions for videobuf2-*.
    1205                 :            :  */
    1206                 :            : 
    1207                 :            : /**
    1208                 :            :  * vb2_buffer_in_use() - return true if the buffer is in use and
    1209                 :            :  * the queue cannot be freed (by the means of VIDIOC_REQBUFS(0)) call.
    1210                 :            :  *
    1211                 :            :  * @vb:         buffer for which plane size should be returned.
    1212                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
    1213                 :            :  */
    1214                 :            : bool vb2_buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb);
    1215                 :            : 
    1216                 :            : /**
    1217                 :            :  * vb2_verify_memory_type() - Check whether the memory type and buffer type
    1218                 :            :  * passed to a buffer operation are compatible with the queue.
    1219                 :            :  *
    1220                 :            :  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
    1221                 :            :  * @memory:     memory model, as defined by enum &vb2_memory.
    1222                 :            :  * @type:       private buffer type whose content is defined by the vb2-core
    1223                 :            :  *              caller. For example, for V4L2, it should match
    1224                 :            :  *              the types defined on enum &v4l2_buf_type.
    1225                 :            :  */
    1226                 :            : int vb2_verify_memory_type(struct vb2_queue *q,
    1227                 :            :                 enum vb2_memory memory, unsigned int type);
    1228                 :            : 
    1229                 :            : /**
    1230                 :            :  * vb2_request_object_is_buffer() - return true if the object is a buffer
    1231                 :            :  *
    1232                 :            :  * @obj:        the request object.
    1233                 :            :  */
    1234                 :            : bool vb2_request_object_is_buffer(struct media_request_object *obj);
    1235                 :            : 
    1236                 :            : /**
    1237                 :            :  * vb2_request_buffer_cnt() - return the number of buffers in the request
    1238                 :            :  *
    1239                 :            :  * @req:        the request.
    1240                 :            :  */
    1241                 :            : unsigned int vb2_request_buffer_cnt(struct media_request *req);
    1242                 :            : 
    1243                 :            : #endif /* _MEDIA_VIDEOBUF2_CORE_H */
    

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