include/media/video-buf.h

   1 /*
   2  * $Id: video-buf.h,v 1.9 2004/11/07 13:17:15 kraxel Exp $
   3  *
   4  * generic helper functions for video4linux capture buffers, to handle
   5  * memory management and PCI DMA.  Right now bttv + saa7134 use it.
   6  *
   7  * The functions expect the hardware being able to scatter gatter
   8  * (i.e. the buffers are not linear in physical memory, but fragmented
   9  * into PAGE_SIZE chunks).  They also assume the driver does not need
  10  * to touch the video data (thus it is probably not useful for USB as
  11  * data often must be uncompressed by the drivers).
  12  *
  13  * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
  14  *
  15  * This program is free software; you can redistribute it and/or modify
  16  * it under the terms of the GNU General Public License as published by
  17  * the Free Software Foundation; either version 2 of the License, or
  18  * (at your option) any later version.
  19  */
  20
  21 #include <linux/videodev.h>
  22
  23 #define UNSET (-1U)
  24
  25 /* --------------------------------------------------------------------- */
  26
  27 /*
  28  * Return a scatterlist for some page-aligned vmalloc()'ed memory
  29  * block (NULL on errors).  Memory for the scatterlist is allocated
  30  * using kmalloc.  The caller must free the memory.
  31  */
  32 struct scatterlist* videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages);
  33
  34 /*
  35  * Return a scatterlist for a an array of userpages (NULL on errors).
  36  * Memory for the scatterlist is allocated using kmalloc.  The caller
  37  * must free the memory.
  38  */
  39 struct scatterlist* videobuf_pages_to_sg(struct page **pages, int nr_pages,
  40                                          int offset);
  41
  42 /* --------------------------------------------------------------------- */
  43
  44 /*
  45  * A small set of helper functions to manage buffers (both userland
  46  * and kernel) for DMA.
  47  *
  48  * videobuf_dma_init_*()
  49  *      creates a buffer.  The userland version takes a userspace
  50  *      pointer + length.  The kernel version just wants the size and
  51  *      does memory allocation too using vmalloc_32().
  52  *
  53  * videobuf_dma_pci_*()
  54  *      see Documentation/DMA-mapping.txt, these functions to
  55  *      basically the same.  The map function does also build a
  56  *      scatterlist for the buffer (and unmap frees it ...)
  57  *
  58  * videobuf_dma_free()
  59  *      no comment ...
  60  *
  61  */
  62
  63 struct videobuf_dmabuf {
  64         u32                 magic;
  65
  66         /* for userland buffer */
  67         int                 offset;
  68         struct page         **pages;
  69
  70         /* for kernel buffers */
  71         void                *vmalloc;
  72
  73         /* for overlay buffers (pci-pci dma) */
  74         dma_addr_t          bus_addr;
  75
  76         /* common */
  77         struct scatterlist  *sglist;
  78         int                 sglen;
  79         int                 nr_pages;
  80         int                 direction;
  81 };
  82
  83 void videobuf_dma_init(struct videobuf_dmabuf *dma);
  84 int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
  85                            unsigned long data, unsigned long size);
  86 int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
  87                              int nr_pages);
  88 int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
  89                               dma_addr_t addr, int nr_pages);
  90 int videobuf_dma_pci_map(struct pci_dev *dev, struct videobuf_dmabuf *dma);
  91 int videobuf_dma_pci_sync(struct pci_dev *dev,
  92                           struct videobuf_dmabuf *dma);
  93 int videobuf_dma_pci_unmap(struct pci_dev *dev, struct videobuf_dmabuf *dma);
  94 int videobuf_dma_free(struct videobuf_dmabuf *dma);
  95
  96 /* --------------------------------------------------------------------- */
  97
  98 /*
  99  * A small set of helper functions to manage video4linux buffers.
 100  *
 101  * struct videobuf_buffer holds the data structures used by the helper
 102  * functions, additionally some commonly used fields for v4l buffers
 103  * (width, height, lists, waitqueue) are in there.  That struct should
 104  * be used as first element in the drivers buffer struct.
 105  *
 106  * about the mmap helpers (videobuf_mmap_*):
 107  *
 108  * The mmaper function allows to map any subset of contingous buffers.
 109  * This includes one mmap() call for all buffers (which the original
 110  * video4linux API uses) as well as one mmap() for every single buffer
 111  * (which v4l2 uses).
 112  *
 113  * If there is a valid mapping for a buffer, buffer->baddr/bsize holds
 114  * userspace address + size which can be feeded into the
 115  * videobuf_dma_init_user function listed above.
 116  *
 117  */
 118
 119 struct videobuf_buffer;
 120 struct videobuf_queue;
 121
 122 struct videobuf_mapping {
 123         unsigned int count;
 124         unsigned long start;
 125         unsigned long end;
 126         struct videobuf_queue *q;
 127 };
 128
 129 enum videobuf_state {
 130         STATE_NEEDS_INIT = 0,
 131         STATE_PREPARED   = 1,
 132         STATE_QUEUED     = 2,
 133         STATE_ACTIVE     = 3,
 134         STATE_DONE       = 4,
 135         STATE_ERROR      = 5,
 136         STATE_IDLE       = 6,
 137 };
 138
 139 struct videobuf_buffer {
 140         unsigned int            i;
 141         u32                     magic;
 142
 143         /* info about the buffer */
 144         unsigned int            width;
 145         unsigned int            height;
 146         unsigned int            bytesperline; /* use only if != 0 */
 147         unsigned long           size;
 148         unsigned int            input;
 149         enum v4l2_field         field;
 150         enum videobuf_state     state;
 151         struct videobuf_dmabuf  dma;
 152         struct list_head        stream;  /* QBUF/DQBUF list */
 153
 154         /* for mmap'ed buffers */
 155         enum v4l2_memory        memory;
 156         size_t                  boff;    /* buffer offset (mmap + overlay) */
 157         size_t                  bsize;   /* buffer size */
 158         unsigned long           baddr;   /* buffer addr (userland ptr!) */
 159         struct videobuf_mapping *map;
 160
 161         /* touched by irq handler */
 162         struct list_head        queue;
 163         wait_queue_head_t       done;
 164         unsigned int            field_count;
 165         struct timeval          ts;
 166 };
 167
 168 struct videobuf_queue_ops {
 169         int (*buf_setup)(struct videobuf_queue *q,
 170                          unsigned int *count, unsigned int *size);
 171         int (*buf_prepare)(struct videobuf_queue *q,
 172                            struct videobuf_buffer *vb,
 173                            enum v4l2_field field);
 174         void (*buf_queue)(struct videobuf_queue *q,
 175                           struct videobuf_buffer *vb);
 176         void (*buf_release)(struct videobuf_queue *q,
 177                             struct videobuf_buffer *vb);
 178 };
 179
 180 struct videobuf_queue {
 181         struct semaphore           lock;
 182         spinlock_t                 *irqlock;
 183         struct pci_dev             *pci;
 184
 185         enum v4l2_buf_type         type;
 186         unsigned int               inputs; /* for V4L2_BUF_FLAG_INPUT */
 187         unsigned int               msize;
 188         enum v4l2_field            field;
 189         enum v4l2_field            last;   /* for field=V4L2_FIELD_ALTERNATE */
 190         struct videobuf_buffer     *bufs[VIDEO_MAX_FRAME];
 191         struct videobuf_queue_ops  *ops;
 192
 193         /* capture via mmap() + ioctl(QBUF/DQBUF) */
 194         unsigned int               streaming;
 195         struct list_head           stream;
 196
 197         /* capture via read() */
 198         unsigned int               reading;
 199         unsigned int               read_off;
 200         struct videobuf_buffer     *read_buf;
 201
 202         /* driver private data */
 203         void                       *priv_data;
 204 };
 205
 206 void* videobuf_alloc(unsigned int size);
 207 int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr);
 208 int videobuf_iolock(struct pci_dev *pci, struct videobuf_buffer *vb,
 209                     struct v4l2_framebuffer *fbuf);
 210
 211 void videobuf_queue_init(struct videobuf_queue *q,
 212                          struct videobuf_queue_ops *ops,
 213                          struct pci_dev *pci,
 214                          spinlock_t *irqlock,
 215                          enum v4l2_buf_type type,
 216                          enum v4l2_field field,
 217                          unsigned int msize,
 218                          void *priv);
 219 int  videobuf_queue_is_busy(struct videobuf_queue *q);
 220 void videobuf_queue_cancel(struct videobuf_queue *q);
 221
 222 enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
 223 void videobuf_status(struct v4l2_buffer *b, struct videobuf_buffer *vb,
 224                      enum v4l2_buf_type type);
 225 int videobuf_reqbufs(struct videobuf_queue *q,
 226                      struct v4l2_requestbuffers *req);
 227 int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
 228 int videobuf_qbuf(struct videobuf_queue *q,
 229                   struct v4l2_buffer *b);
 230 int videobuf_dqbuf(struct videobuf_queue *q,
 231                    struct v4l2_buffer *b, int nonblocking);
 232 int videobuf_streamon(struct videobuf_queue *q);
 233 int videobuf_streamoff(struct videobuf_queue *q);
 234
 235 int videobuf_read_start(struct videobuf_queue *q);
 236 void videobuf_read_stop(struct videobuf_queue *q);
 237 ssize_t videobuf_read_stream(struct videobuf_queue *q,
 238                              char __user *data, size_t count, loff_t *ppos,
 239                              int vbihack, int nonblocking);
 240 ssize_t videobuf_read_one(struct videobuf_queue *q,
 241                           char __user *data, size_t count, loff_t *ppos,
 242                           int nonblocking);
 243 unsigned int videobuf_poll_stream(struct file *file,
 244                                   struct videobuf_queue *q,
 245                                   poll_table *wait);
 246
 247 int videobuf_mmap_setup(struct videobuf_queue *q,
 248                         unsigned int bcount, unsigned int bsize,
 249                         enum v4l2_memory memory);
 250 int videobuf_mmap_free(struct videobuf_queue *q);
 251 int videobuf_mmap_mapper(struct videobuf_queue *q,
 252                          struct vm_area_struct *vma);
 253
 254 /* --------------------------------------------------------------------- */
 255
 256 /*
 257  * Local variables:
 258  * c-basic-offset: 8
 259  * End:
 260  */