include/media/video-buf.h

   1 /*
   2  *
   3  * generic helper functions for video4linux capture buffers, to handle
   4  * memory management and PCI DMA.
   5  * Right now, bttv, saa7134, saa7146 and cx88 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.
  11  *
  12  * device specific map/unmap/sync stuff now are mapped as file operations
  13  * to allow its usage by USB and virtual devices.
  14  *
  15  * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
  16  * (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.org>
  17  * (c) 2006 Ted Walther and John Sokol
  18  *
  19  * This program is free software; you can redistribute it and/or modify
  20  * it under the terms of the GNU General Public License as published by
  21  * the Free Software Foundation; either version 2 of the License, or
  22  * (at your option) any later version.
  23  */
  24
  25 #include <linux/videodev2.h>
  26
  27 #define UNSET (-1U)
  28
  29 /* --------------------------------------------------------------------- */
  30
  31 /*
  32  * Return a scatterlist for some page-aligned vmalloc()'ed memory
  33  * block (NULL on errors).  Memory for the scatterlist is allocated
  34  * using kmalloc.  The caller must free the memory.
  35  */
  36 struct scatterlist* videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages);
  37
  38 /*
  39  * Return a scatterlist for a an array of userpages (NULL on errors).
  40  * Memory for the scatterlist is allocated using kmalloc.  The caller
  41  * must free the memory.
  42  */
  43 struct scatterlist* videobuf_pages_to_sg(struct page **pages, int nr_pages,
  44                                          int offset);
  45
  46 struct videobuf_buffer;
  47 struct videobuf_queue;
  48
  49 /* --------------------------------------------------------------------- */
  50
  51 /*
  52  * A small set of helper functions to manage buffers (both userland
  53  * and kernel) for DMA.
  54  *
  55  * videobuf_dma_init_*()
  56  *      creates a buffer.  The userland version takes a userspace
  57  *      pointer + length.  The kernel version just wants the size and
  58  *      does memory allocation too using vmalloc_32().
  59  *
  60  * videobuf_dma_*()
  61  *      see Documentation/DMA-mapping.txt, these functions to
  62  *      basically the same.  The map function does also build a
  63  *      scatterlist for the buffer (and unmap frees it ...)
  64  *
  65  * videobuf_dma_free()
  66  *      no comment ...
  67  *
  68  */
  69
  70 struct videobuf_dmabuf {
  71         u32                 magic;
  72
  73         /* for userland buffer */
  74         int                 offset;
  75         struct page         **pages;
  76
  77         /* for kernel buffers */
  78         void                *vmalloc;
  79
  80         /* for overlay buffers (pci-pci dma) */
  81         dma_addr_t          bus_addr;
  82
  83         /* common */
  84         struct scatterlist  *sglist;
  85         int                 sglen;
  86         int                 nr_pages;
  87         int                 direction;
  88 };
  89
  90 void videobuf_dma_init(struct videobuf_dmabuf *dma);
  91 int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
  92                            unsigned long data, unsigned long size);
  93 int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
  94                              int nr_pages);
  95 int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
  96                               dma_addr_t addr, int nr_pages);
  97 int videobuf_dma_free(struct videobuf_dmabuf *dma);
  98
  99 int videobuf_dma_map(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
 100 int videobuf_dma_sync(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
 101 int videobuf_dma_unmap(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
 102
 103         /*FIXME: these variants are used only on *-alsa code, where videobuf is
 104          * used without queue
 105          */
 106 int videobuf_pci_dma_map(struct pci_dev *pci,struct videobuf_dmabuf *dma);
 107 int videobuf_pci_dma_unmap(struct pci_dev *pci,struct videobuf_dmabuf *dma);
 108
 109 /* --------------------------------------------------------------------- */
 110
 111 /*
 112  * A small set of helper functions to manage video4linux buffers.
 113  *
 114  * struct videobuf_buffer holds the data structures used by the helper
 115  * functions, additionally some commonly used fields for v4l buffers
 116  * (width, height, lists, waitqueue) are in there.  That struct should
 117  * be used as first element in the drivers buffer struct.
 118  *
 119  * about the mmap helpers (videobuf_mmap_*):
 120  *
 121  * The mmaper function allows to map any subset of contingous buffers.
 122  * This includes one mmap() call for all buffers (which the original
 123  * video4linux API uses) as well as one mmap() for every single buffer
 124  * (which v4l2 uses).
 125  *
 126  * If there is a valid mapping for a buffer, buffer->baddr/bsize holds
 127  * userspace address + size which can be feeded into the
 128  * videobuf_dma_init_user function listed above.
 129  *
 130  */
 131
 132 struct videobuf_mapping {
 133         unsigned int count;
 134         unsigned long start;
 135         unsigned long end;
 136         struct videobuf_queue *q;
 137 };
 138
 139 enum videobuf_state {
 140         STATE_NEEDS_INIT = 0,
 141         STATE_PREPARED   = 1,
 142         STATE_QUEUED     = 2,
 143         STATE_ACTIVE     = 3,
 144         STATE_DONE       = 4,
 145         STATE_ERROR      = 5,
 146         STATE_IDLE       = 6,
 147 };
 148
 149 struct videobuf_buffer {
 150         unsigned int            i;
 151         u32                     magic;
 152
 153         /* info about the buffer */
 154         unsigned int            width;
 155         unsigned int            height;
 156         unsigned int            bytesperline; /* use only if != 0 */
 157         unsigned long           size;
 158         unsigned int            input;
 159         enum v4l2_field         field;
 160         enum videobuf_state     state;
 161         struct videobuf_dmabuf  dma;
 162         struct list_head        stream;  /* QBUF/DQBUF list */
 163
 164         /* for mmap'ed buffers */
 165         enum v4l2_memory        memory;
 166         size_t                  boff;    /* buffer offset (mmap + overlay) */
 167         size_t                  bsize;   /* buffer size */
 168         unsigned long           baddr;   /* buffer addr (userland ptr!) */
 169         struct videobuf_mapping *map;
 170
 171         /* touched by irq handler */
 172         struct list_head        queue;
 173         wait_queue_head_t       done;
 174         unsigned int            field_count;
 175         struct timeval          ts;
 176 };
 177
 178 typedef int (vb_map_sg_t)(void *dev,struct scatterlist *sglist,int nr_pages,
 179                                         int direction);
 180
 181
 182 struct videobuf_queue_ops {
 183         int (*buf_setup)(struct videobuf_queue *q,
 184                          unsigned int *count, unsigned int *size);
 185         int (*buf_prepare)(struct videobuf_queue *q,
 186                            struct videobuf_buffer *vb,
 187                            enum v4l2_field field);
 188         void (*buf_queue)(struct videobuf_queue *q,
 189                           struct videobuf_buffer *vb);
 190         void (*buf_release)(struct videobuf_queue *q,
 191                             struct videobuf_buffer *vb);
 192
 193         /* Helper operations - device dependent.
 194          * If null, videobuf_init defaults all to PCI handling
 195          */
 196
 197         vb_map_sg_t     *vb_map_sg;
 198         vb_map_sg_t     *vb_dma_sync_sg;
 199         vb_map_sg_t     *vb_unmap_sg;
 200 };
 201
 202 struct videobuf_queue {
 203         struct mutex               lock;
 204         spinlock_t                 *irqlock;
 205         void                       *dev; /* on pci, points to struct pci_dev */
 206
 207         enum v4l2_buf_type         type;
 208         unsigned int               inputs; /* for V4L2_BUF_FLAG_INPUT */
 209         unsigned int               msize;
 210         enum v4l2_field            field;
 211         enum v4l2_field            last;   /* for field=V4L2_FIELD_ALTERNATE */
 212         struct videobuf_buffer     *bufs[VIDEO_MAX_FRAME];
 213         struct videobuf_queue_ops  *ops;
 214
 215         /* capture via mmap() + ioctl(QBUF/DQBUF) */
 216         unsigned int               streaming;
 217         struct list_head           stream;
 218
 219         /* capture via read() */
 220         unsigned int               reading;
 221         unsigned int               read_off;
 222         struct videobuf_buffer     *read_buf;
 223
 224         /* driver private data */
 225         void                       *priv_data;
 226 };
 227
 228 void* videobuf_alloc(unsigned int size);
 229 int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr);
 230 int videobuf_iolock(struct videobuf_queue* q, struct videobuf_buffer *vb,
 231                 struct v4l2_framebuffer *fbuf);
 232
 233 /* Maps fops to PCI stuff */
 234 void videobuf_queue_pci(struct videobuf_queue* q);
 235
 236 void videobuf_queue_init(struct videobuf_queue *q,
 237                          struct videobuf_queue_ops *ops,
 238                          void *dev,
 239                          spinlock_t *irqlock,
 240                          enum v4l2_buf_type type,
 241                          enum v4l2_field field,
 242                          unsigned int msize,
 243                          void *priv);
 244 int  videobuf_queue_is_busy(struct videobuf_queue *q);
 245 void videobuf_queue_cancel(struct videobuf_queue *q);
 246
 247 enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
 248 void videobuf_status(struct v4l2_buffer *b, struct videobuf_buffer *vb,
 249                      enum v4l2_buf_type type);
 250 int videobuf_reqbufs(struct videobuf_queue *q,
 251                      struct v4l2_requestbuffers *req);
 252 int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
 253 int videobuf_qbuf(struct videobuf_queue *q,
 254                   struct v4l2_buffer *b);
 255 int videobuf_dqbuf(struct videobuf_queue *q,
 256                    struct v4l2_buffer *b, int nonblocking);
 257 int videobuf_streamon(struct videobuf_queue *q);
 258 int videobuf_streamoff(struct videobuf_queue *q);
 259
 260 int videobuf_read_start(struct videobuf_queue *q);
 261 void videobuf_read_stop(struct videobuf_queue *q);
 262 ssize_t videobuf_read_stream(struct videobuf_queue *q,
 263                              char __user *data, size_t count, loff_t *ppos,
 264                              int vbihack, int nonblocking);
 265 ssize_t videobuf_read_one(struct videobuf_queue *q,
 266                           char __user *data, size_t count, loff_t *ppos,
 267                           int nonblocking);
 268 unsigned int videobuf_poll_stream(struct file *file,
 269                                   struct videobuf_queue *q,
 270                                   poll_table *wait);
 271
 272 int videobuf_mmap_setup(struct videobuf_queue *q,
 273                         unsigned int bcount, unsigned int bsize,
 274                         enum v4l2_memory memory);
 275 int videobuf_mmap_free(struct videobuf_queue *q);
 276 int videobuf_mmap_mapper(struct videobuf_queue *q,
 277                          struct vm_area_struct *vma);
 278
 279 /* --------------------------------------------------------------------- */
 280
 281 /*
 282  * Local variables:
 283  * c-basic-offset: 8
 284  * End:
 285  */