include/media/video-buf.h

   1 /*
   2  *
   3  * generic helper functions for video4linux capture buffers, to handle
   4  * memory management and PCI DMA.  Right now bttv + saa7134 use it.
   5  *
   6  * The functions expect the hardware being able to scatter gatter
   7  * (i.e. the buffers are not linear in physical memory, but fragmented
   8  * into PAGE_SIZE chunks).  They also assume the driver does not need
   9  * to touch the video data (thus it is probably not useful for USB as
  10  * data often must be uncompressed by the drivers).
  11  *
  12  * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  */
  19
  20 #include <linux/videodev.h>
  21
  22 #define UNSET (-1U)
  23
  24 /* --------------------------------------------------------------------- */
  25
  26 /*
  27  * Return a scatterlist for some page-aligned vmalloc()'ed memory
  28  * block (NULL on errors).  Memory for the scatterlist is allocated
  29  * using kmalloc.  The caller must free the memory.
  30  */
  31 struct scatterlist* videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages);
  32
  33 /*
  34  * Return a scatterlist for a an array of userpages (NULL on errors).
  35  * Memory for the scatterlist is allocated using kmalloc.  The caller
  36  * must free the memory.
  37  */
  38 struct scatterlist* videobuf_pages_to_sg(struct page **pages, int nr_pages,
  39                                          int offset);
  40
  41 /* --------------------------------------------------------------------- */
  42
  43 /*
  44  * A small set of helper functions to manage buffers (both userland
  45  * and kernel) for DMA.
  46  *
  47  * videobuf_dma_init_*()
  48  *      creates a buffer.  The userland version takes a userspace
  49  *      pointer + length.  The kernel version just wants the size and
  50  *      does memory allocation too using vmalloc_32().
  51  *
  52  * videobuf_dma_pci_*()
  53  *      see Documentation/DMA-mapping.txt, these functions to
  54  *      basically the same.  The map function does also build a
  55  *      scatterlist for the buffer (and unmap frees it ...)
  56  *
  57  * videobuf_dma_free()
  58  *      no comment ...
  59  *
  60  */
  61
  62 struct videobuf_dmabuf {
  63         u32                 magic;
  64
  65         /* for userland buffer */
  66         int                 offset;
  67         struct page         **pages;
  68
  69         /* for kernel buffers */
  70         void                *vmalloc;
  71
  72         /* for overlay buffers (pci-pci dma) */
  73         dma_addr_t          bus_addr;
  74
  75         /* common */
  76         struct scatterlist  *sglist;
  77         int                 sglen;
  78         int                 nr_pages;
  79         int                 direction;
  80 };
  81
  82 void videobuf_dma_init(struct videobuf_dmabuf *dma);
  83 int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
  84                            unsigned long data, unsigned long size);
  85 int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
  86                              int nr_pages);
  87 int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
  88                               dma_addr_t addr, int nr_pages);
  89 int videobuf_dma_pci_map(struct pci_dev *dev, struct videobuf_dmabuf *dma);
  90 int videobuf_dma_pci_sync(struct pci_dev *dev,
  91                           struct videobuf_dmabuf *dma);
  92 int videobuf_dma_pci_unmap(struct pci_dev *dev, struct videobuf_dmabuf *dma);
  93 int videobuf_dma_free(struct videobuf_dmabuf *dma);
  94
  95 /* --------------------------------------------------------------------- */
  96
  97 /*
  98  * A small set of helper functions to manage video4linux buffers.
  99  *
 100  * struct videobuf_buffer holds the data structures used by the helper
 101  * functions, additionally some commonly used fields for v4l buffers
 102  * (width, height, lists, waitqueue) are in there.  That struct should
 103  * be used as first element in the drivers buffer struct.
 104  *
 105  * about the mmap helpers (videobuf_mmap_*):
 106  *
 107  * The mmaper function allows to map any subset of contingous buffers.
 108  * This includes one mmap() call for all buffers (which the original
 109  * video4linux API uses) as well as one mmap() for every single buffer
 110  * (which v4l2 uses).
 111  *
 112  * If there is a valid mapping for a buffer, buffer->baddr/bsize holds
 113  * userspace address + size which can be feeded into the
 114  * videobuf_dma_init_user function listed above.
 115  *
 116  */
 117
 118 struct videobuf_buffer;
 119 struct videobuf_queue;
 120
 121 struct videobuf_mapping {
 122         unsigned int count;
 123         unsigned long start;
 124         unsigned long end;
 125         struct videobuf_queue *q;
 126 };
 127
 128 enum videobuf_state {
 129         STATE_NEEDS_INIT = 0,
 130         STATE_PREPARED   = 1,
 131         STATE_QUEUED     = 2,
 132         STATE_ACTIVE     = 3,
 133         STATE_DONE       = 4,
 134         STATE_ERROR      = 5,
 135         STATE_IDLE       = 6,
 136 };
 137
 138 struct videobuf_buffer {
 139         unsigned int            i;
 140         u32                     magic;
 141
 142         /* info about the buffer */
 143         unsigned int            width;
 144         unsigned int            height;
 145         unsigned int            bytesperline; /* use only if != 0 */
 146         unsigned long           size;
 147         unsigned int            input;
 148         enum v4l2_field         field;
 149         enum videobuf_state     state;
 150         struct videobuf_dmabuf  dma;
 151         struct list_head        stream;  /* QBUF/DQBUF list */
 152
 153         /* for mmap'ed buffers */
 154         enum v4l2_memory        memory;
 155         size_t                  boff;    /* buffer offset (mmap + overlay) */
 156         size_t                  bsize;   /* buffer size */
 157         unsigned long           baddr;   /* buffer addr (userland ptr!) */
 158         struct videobuf_mapping *map;
 159
 160         /* touched by irq handler */
 161         struct list_head        queue;
 162         wait_queue_head_t       done;
 163         unsigned int            field_count;
 164         struct timeval          ts;
 165 };
 166
 167 struct videobuf_queue_ops {
 168         int (*buf_setup)(struct videobuf_queue *q,
 169                          unsigned int *count, unsigned int *size);
 170         int (*buf_prepare)(struct videobuf_queue *q,
 171                            struct videobuf_buffer *vb,
 172                            enum v4l2_field field);
 173         void (*buf_queue)(struct videobuf_queue *q,
 174                           struct videobuf_buffer *vb);
 175         void (*buf_release)(struct videobuf_queue *q,
 176                             struct videobuf_buffer *vb);
 177 };
 178
 179 struct videobuf_queue {
 180         struct semaphore           lock;
 181         spinlock_t                 *irqlock;
 182         struct pci_dev             *pci;
 183
 184         enum v4l2_buf_type         type;
 185         unsigned int               inputs; /* for V4L2_BUF_FLAG_INPUT */
 186         unsigned int               msize;
 187         enum v4l2_field            field;
 188         enum v4l2_field            last;   /* for field=V4L2_FIELD_ALTERNATE */
 189         struct videobuf_buffer     *bufs[VIDEO_MAX_FRAME];
 190         struct videobuf_queue_ops  *ops;
 191
 192         /* capture via mmap() + ioctl(QBUF/DQBUF) */
 193         unsigned int               streaming;
 194         struct list_head           stream;
 195
 196         /* capture via read() */
 197         unsigned int               reading;
 198         unsigned int               read_off;
 199         struct videobuf_buffer     *read_buf;
 200
 201         /* driver private data */
 202         void                       *priv_data;
 203 };
 204
 205 void* videobuf_alloc(unsigned int size);
 206 int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr);
 207 int videobuf_iolock(struct pci_dev *pci, struct videobuf_buffer *vb,
 208                     struct v4l2_framebuffer *fbuf);
 209
 210 void videobuf_queue_init(struct videobuf_queue *q,
 211                          struct videobuf_queue_ops *ops,
 212                          struct pci_dev *pci,
 213                          spinlock_t *irqlock,
 214                          enum v4l2_buf_type type,
 215                          enum v4l2_field field,
 216                          unsigned int msize,
 217                          void *priv);
 218 int  videobuf_queue_is_busy(struct videobuf_queue *q);
 219 void videobuf_queue_cancel(struct videobuf_queue *q);
 220
 221 enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
 222 void videobuf_status(struct v4l2_buffer *b, struct videobuf_buffer *vb,
 223                      enum v4l2_buf_type type);
 224 int videobuf_reqbufs(struct videobuf_queue *q,
 225                      struct v4l2_requestbuffers *req);
 226 int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
 227 int videobuf_qbuf(struct videobuf_queue *q,
 228                   struct v4l2_buffer *b);
 229 int videobuf_dqbuf(struct videobuf_queue *q,
 230                    struct v4l2_buffer *b, int nonblocking);
 231 int videobuf_streamon(struct videobuf_queue *q);
 232 int videobuf_streamoff(struct videobuf_queue *q);
 233
 234 int videobuf_read_start(struct videobuf_queue *q);
 235 void videobuf_read_stop(struct videobuf_queue *q);
 236 ssize_t videobuf_read_stream(struct videobuf_queue *q,
 237                              char __user *data, size_t count, loff_t *ppos,
 238                              int vbihack, int nonblocking);
 239 ssize_t videobuf_read_one(struct videobuf_queue *q,
 240                           char __user *data, size_t count, loff_t *ppos,
 241                           int nonblocking);
 242 unsigned int videobuf_poll_stream(struct file *file,
 243                                   struct videobuf_queue *q,
 244                                   poll_table *wait);
 245
 246 int videobuf_mmap_setup(struct videobuf_queue *q,
 247                         unsigned int bcount, unsigned int bsize,
 248                         enum v4l2_memory memory);
 249 int videobuf_mmap_free(struct videobuf_queue *q);
 250 int videobuf_mmap_mapper(struct videobuf_queue *q,
 251                          struct vm_area_struct *vma);
 252
 253 /* --------------------------------------------------------------------- */
 254
 255 /*
 256  * Local variables:
 257  * c-basic-offset: 8
 258  * End:
 259  */