include/media/video-buf.h

   1 /*
   2  * generic helper functions for video4linux capture buffers, to handle
   3  * memory management and PCI DMA.  Right now bttv + saa7134 use it.
   4  *
   5  * The functions expect the hardware being able to scatter gatter
   6  * (i.e. the buffers are not linear in physical memory, but fragmented
   7  * into PAGE_SIZE chunks).  They also assume the driver does not need
   8  * to touch the video data (thus it is probably not useful for USB as
   9  * data often must be uncompressed by the drivers).
  10  *
  11  * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2 of the License, or
  16  * (at your option) any later version.
  17  */
  18
  19 #include <linux/videodev.h>
  20
  21 /* --------------------------------------------------------------------- */
  22
  23 /*
  24  * Return a scatterlist for some page-aligned vmalloc()'ed memory
  25  * block (NULL on errors).  Memory for the scatterlist is allocated
  26  * using kmalloc.  The caller must free the memory.
  27  */
  28 struct scatterlist* videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages);
  29
  30 /*
  31  * Return a scatterlist for a an array of userpages (NULL on errors).
  32  * Memory for the scatterlist is allocated using kmalloc.  The caller
  33  * must free the memory.
  34  */
  35 struct scatterlist* videobuf_pages_to_sg(struct page **pages, int nr_pages,
  36                                          int offset);
  37 int videobuf_lock(struct page **pages, int nr_pages);
  38 int videobuf_unlock(struct page **pages, int nr_pages);
  39
  40 /* --------------------------------------------------------------------- */
  41
  42 /*
  43  * A small set of helper functions to manage buffers (both userland
  44  * and kernel) for DMA.
  45  *
  46  * videobuf_init_*_dmabuf()
  47  *      creates a buffer.  The userland version takes a userspace
  48  *      pointer + length.  The kernel version just wants the size and
  49  *      does memory allocation too using vmalloc_32().
  50  *
  51  * videobuf_pci_*_dmabuf()
  52  *      see Documentation/DMA-mapping.txt, these functions to
  53  *      basically the same.  The map function does also build a
  54  *      scatterlist for the buffer (and unmap frees it ...)
  55  *
  56  * videobuf_free_dmabuf()
  57  *      no comment ...
  58  *
  59  */
  60
  61 struct videobuf_dmabuf {
  62         /* for userland buffer */
  63         int                 offset;
  64         struct page         **pages;
  65
  66         /* for kernel buffers */
  67         void                *vmalloc;
  68
  69         /* common */
  70         struct scatterlist  *sglist;
  71         int                 sglen;
  72         int                 nr_pages;
  73         int                 direction;
  74 };
  75
  76 int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
  77                            unsigned long data, unsigned long size);
  78 int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
  79                              int nr_pages);
  80 int videobuf_dma_pci_map(struct pci_dev *dev, struct videobuf_dmabuf *dma);
  81 int videobuf_dma_pci_sync(struct pci_dev *dev,
  82                           struct videobuf_dmabuf *dma);
  83 int videobuf_dma_pci_unmap(struct pci_dev *dev, struct videobuf_dmabuf *dma);
  84 int videobuf_dma_free(struct videobuf_dmabuf *dma);
  85
  86 /* --------------------------------------------------------------------- */
  87
  88 /*
  89  * A small set of helper functions to manage video4linux buffers.
  90  *
  91  * struct videobuf_buffer holds the data structures used by the helper
  92  * functions, additionally some commonly used fields for v4l buffers
  93  * (width, height, lists, waitqueue) are in there.  That struct should
  94  * be used as first element in the drivers buffer struct.
  95  *
  96  * about the mmap helpers (videobuf_mmap_*):
  97  *
  98  * The mmaper function allows to map any subset of contingous buffers.
  99  * This includes one mmap() call for all buffers (which the original
 100  * video4linux API uses) as well as one mmap() for every single buffer
 101  * (which v4l2 uses).
 102  *
 103  * If there is a valid mapping for a buffer, buffer->baddr/bsize holds
 104  * userspace address + size which can be feeded into the
 105  * videobuf_dma_init_user function listed above.
 106  *
 107  */
 108
 109 struct videobuf_buffer;
 110 struct videobuf_queue;
 111
 112 struct videobuf_mapping {
 113         unsigned int count;
 114         int highmem_ok;
 115         unsigned long start;
 116         unsigned long end;
 117         struct videobuf_queue *q;
 118 };
 119
 120 enum videobuf_state {
 121         STATE_NEEDS_INIT = 0,
 122         STATE_PREPARED   = 1,
 123         STATE_QUEUED     = 2,
 124         STATE_ACTIVE     = 3,
 125         STATE_DONE       = 4,
 126         STATE_ERROR      = 5,
 127         STATE_IDLE       = 6,
 128 };
 129
 130 struct videobuf_buffer {
 131         unsigned int            i;
 132
 133         /* info about the buffer */
 134         unsigned int            width;
 135         unsigned int            height;
 136         unsigned long           size;
 137         enum v4l2_field         field;
 138         enum videobuf_state     state;
 139         struct videobuf_dmabuf  dma;
 140         struct list_head        stream;  /* QBUF/DQBUF list */
 141
 142         /* for mmap'ed buffers */
 143         size_t                  boff;    /* buffer offset (mmap) */
 144         size_t                  bsize;   /* buffer size */
 145         unsigned long           baddr;   /* buffer addr (userland ptr!) */
 146         struct videobuf_mapping *map;
 147
 148         /* touched by irq handler */
 149         struct list_head        queue;
 150         wait_queue_head_t       done;
 151         unsigned int            field_count;
 152         struct timeval          ts;
 153 };
 154
 155 struct videobuf_queue_ops {
 156         int (*buf_setup)(struct file *file,
 157                          unsigned int *count, unsigned int *size);
 158         int (*buf_prepare)(struct file *file,struct videobuf_buffer *vb,
 159                            enum v4l2_field field);
 160         void (*buf_queue)(struct file *file,struct videobuf_buffer *vb);
 161         void (*buf_release)(struct file *file,struct videobuf_buffer *vb);
 162 };
 163
 164 struct videobuf_queue {
 165         struct semaphore           lock;
 166         spinlock_t                 *irqlock;
 167         struct pci_dev             *pci;
 168
 169         enum v4l2_buf_type         type;
 170         unsigned int               msize;
 171         enum v4l2_field            field;
 172         enum v4l2_field            last; /* for field=V4L2_FIELD_ALTERNATE */
 173         struct videobuf_buffer     *bufs[VIDEO_MAX_FRAME];
 174         struct videobuf_queue_ops  *ops;
 175
 176         /* capture via mmap() + ioctl(QBUF/DQBUF) */
 177         unsigned int               streaming;
 178         struct list_head           stream;
 179
 180         /* capture via read() */
 181         unsigned int               reading;
 182         unsigned int               read_off;
 183         struct videobuf_buffer     *read_buf;
 184 };
 185
 186 void* videobuf_alloc(unsigned int size);
 187 int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr);
 188 int videobuf_iolock(struct pci_dev *pci, struct videobuf_buffer *vb);
 189
 190 void videobuf_queue_init(struct videobuf_queue *q,
 191                          struct videobuf_queue_ops *ops,
 192                          struct pci_dev *pci, spinlock_t *irqlock,
 193                          enum v4l2_buf_type type,
 194                          enum v4l2_field field,
 195                          unsigned int msize);
 196 int  videobuf_queue_is_busy(struct videobuf_queue *q);
 197 void videobuf_queue_cancel(struct file *file, struct videobuf_queue *q);
 198
 199 enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
 200 void videobuf_status(struct v4l2_buffer *b, struct videobuf_buffer *vb,
 201                      enum v4l2_buf_type type);
 202 int videobuf_reqbufs(struct file *file, struct videobuf_queue *q,
 203                      struct v4l2_requestbuffers *req);
 204 int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
 205 int videobuf_qbuf(struct file *file, struct videobuf_queue *q,
 206                   struct v4l2_buffer *b);
 207 int videobuf_dqbuf(struct file *file, struct videobuf_queue *q,
 208                    struct v4l2_buffer *b);
 209 int videobuf_streamon(struct file *file, struct videobuf_queue *q);
 210 int videobuf_streamoff(struct file *file, struct videobuf_queue *q);
 211
 212 int videobuf_read_start(struct file *file, struct videobuf_queue *q);
 213 void videobuf_read_stop(struct file *file, struct videobuf_queue *q);
 214 ssize_t videobuf_read_stream(struct file *file, struct videobuf_queue *q,
 215                              char *data, size_t count, loff_t *ppos,
 216                              int vbihack);
 217 ssize_t videobuf_read_one(struct file *file, struct videobuf_queue *q,
 218                           char *data, size_t count, loff_t *ppos);
 219 unsigned int videobuf_poll_stream(struct file *file,
 220                                   struct videobuf_queue *q,
 221                                   poll_table *wait);
 222
 223 int videobuf_mmap_setup(struct file *file, struct videobuf_queue *q,
 224                         unsigned int bcount, unsigned int bsize);
 225 int videobuf_mmap_free(struct file *file, struct videobuf_queue *q);
 226 int videobuf_mmap_mapper(struct vm_area_struct *vma,
 227                          struct videobuf_queue *q);
 228
 229 /* --------------------------------------------------------------------- */
 230
 231 /*
 232  * Local variables:
 233  * c-basic-offset: 8
 234  * End:
 235  */