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 #include <linux/poll.h>
  27
  28 #define UNSET (-1U)
  29
  30 /* --------------------------------------------------------------------- */
  31
  32 /*
  33  * Return a scatterlist for some page-aligned vmalloc()'ed memory
  34  * block (NULL on errors).  Memory for the scatterlist is allocated
  35  * using kmalloc.  The caller must free the memory.
  36  */
  37 struct scatterlist* videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages);
  38
  39 /*
  40  * Return a scatterlist for a an array of userpages (NULL on errors).
  41  * Memory for the scatterlist is allocated using kmalloc.  The caller
  42  * must free the memory.
  43  */
  44 struct scatterlist* videobuf_pages_to_sg(struct page **pages, int nr_pages,
  45                                          int offset);
  46
  47 struct videobuf_buffer;
  48 struct videobuf_queue;
  49
  50 /* --------------------------------------------------------------------- */
  51
  52 /*
  53  * A small set of helper functions to manage buffers (both userland
  54  * and kernel) for DMA.
  55  *
  56  * videobuf_dma_init_*()
  57  *      creates a buffer.  The userland version takes a userspace
  58  *      pointer + length.  The kernel version just wants the size and
  59  *      does memory allocation too using vmalloc_32().
  60  *
  61  * videobuf_dma_*()
  62  *      see Documentation/DMA-mapping.txt, these functions to
  63  *      basically the same.  The map function does also build a
  64  *      scatterlist for the buffer (and unmap frees it ...)
  65  *
  66  * videobuf_dma_free()
  67  *      no comment ...
  68  *
  69  */
  70
  71 struct videobuf_dmabuf {
  72         u32                 magic;
  73
  74         /* for userland buffer */
  75         int                 offset;
  76         struct page         **pages;
  77
  78         /* for kernel buffers */
  79         void                *vmalloc;
  80
  81         /* Stores the userspace pointer to vmalloc area */
  82         void                *varea;
  83
  84         /* for overlay buffers (pci-pci dma) */
  85         dma_addr_t          bus_addr;
  86
  87         /* common */
  88         struct scatterlist  *sglist;
  89         int                 sglen;
  90         int                 nr_pages;
  91         int                 direction;
  92 };
  93
  94 void videobuf_dma_init(struct videobuf_dmabuf *dma);
  95 int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
  96                            unsigned long data, unsigned long size);
  97 int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
  98                              int nr_pages);
  99 int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
 100                               dma_addr_t addr, int nr_pages);
 101 int videobuf_dma_free(struct videobuf_dmabuf *dma);
 102
 103 int videobuf_dma_map(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
 104 int videobuf_dma_sync(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
 105 int videobuf_dma_unmap(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
 106
 107         /*FIXME: these variants are used only on *-alsa code, where videobuf is
 108          * used without queue
 109          */
 110 int videobuf_pci_dma_map(struct pci_dev *pci,struct videobuf_dmabuf *dma);
 111 int videobuf_pci_dma_unmap(struct pci_dev *pci,struct videobuf_dmabuf *dma);
 112
 113 /* --------------------------------------------------------------------- */
 114
 115 /*
 116  * A small set of helper functions to manage video4linux buffers.
 117  *
 118  * struct videobuf_buffer holds the data structures used by the helper
 119  * functions, additionally some commonly used fields for v4l buffers
 120  * (width, height, lists, waitqueue) are in there.  That struct should
 121  * be used as first element in the drivers buffer struct.
 122  *
 123  * about the mmap helpers (videobuf_mmap_*):
 124  *
 125  * The mmaper function allows to map any subset of contingous buffers.
 126  * This includes one mmap() call for all buffers (which the original
 127  * video4linux API uses) as well as one mmap() for every single buffer
 128  * (which v4l2 uses).
 129  *
 130  * If there is a valid mapping for a buffer, buffer->baddr/bsize holds
 131  * userspace address + size which can be feeded into the
 132  * videobuf_dma_init_user function listed above.
 133  *
 134  */
 135
 136 struct videobuf_mapping {
 137         unsigned int count;
 138         unsigned long start;
 139         unsigned long end;
 140         struct videobuf_queue *q;
 141 };
 142
 143 enum videobuf_state {
 144         STATE_NEEDS_INIT = 0,
 145         STATE_PREPARED   = 1,
 146         STATE_QUEUED     = 2,
 147         STATE_ACTIVE     = 3,
 148         STATE_DONE       = 4,
 149         STATE_ERROR      = 5,
 150         STATE_IDLE       = 6,
 151 };
 152
 153 struct videobuf_buffer {
 154         unsigned int            i;
 155         u32                     magic;
 156
 157         /* info about the buffer */
 158         unsigned int            width;
 159         unsigned int            height;
 160         unsigned int            bytesperline; /* use only if != 0 */
 161         unsigned long           size;
 162         unsigned int            input;
 163         enum v4l2_field         field;
 164         enum videobuf_state     state;
 165         struct videobuf_dmabuf  dma;
 166         struct list_head        stream;  /* QBUF/DQBUF list */
 167
 168         /* for mmap'ed buffers */
 169         enum v4l2_memory        memory;
 170         size_t                  boff;    /* buffer offset (mmap + overlay) */
 171         size_t                  bsize;   /* buffer size */
 172         unsigned long           baddr;   /* buffer addr (userland ptr!) */
 173         struct videobuf_mapping *map;
 174
 175         /* touched by irq handler */
 176         struct list_head        queue;
 177         wait_queue_head_t       done;
 178         unsigned int            field_count;
 179         struct timeval          ts;
 180 };
 181
 182 typedef int (vb_map_sg_t)(void *dev,struct scatterlist *sglist,int nr_pages,
 183                                         int direction);
 184
 185
 186 struct videobuf_queue_ops {
 187         int (*buf_setup)(struct videobuf_queue *q,
 188                          unsigned int *count, unsigned int *size);
 189         int (*buf_prepare)(struct videobuf_queue *q,
 190                            struct videobuf_buffer *vb,
 191                            enum v4l2_field field);
 192         void (*buf_queue)(struct videobuf_queue *q,
 193                           struct videobuf_buffer *vb);
 194         void (*buf_release)(struct videobuf_queue *q,
 195                             struct videobuf_buffer *vb);
 196
 197         /* Helper operations - device dependent.
 198          * If null, videobuf_init defaults all to PCI handling
 199          */
 200
 201         vb_map_sg_t     *vb_map_sg;
 202         vb_map_sg_t     *vb_dma_sync_sg;
 203         vb_map_sg_t     *vb_unmap_sg;
 204 };
 205
 206 struct videobuf_queue {
 207         struct mutex               lock;
 208         spinlock_t                 *irqlock;
 209         void                       *dev; /* on pci, points to struct pci_dev */
 210
 211         enum v4l2_buf_type         type;
 212         unsigned int               inputs; /* for V4L2_BUF_FLAG_INPUT */
 213         unsigned int               msize;
 214         enum v4l2_field            field;
 215         enum v4l2_field            last;   /* for field=V4L2_FIELD_ALTERNATE */
 216         struct videobuf_buffer     *bufs[VIDEO_MAX_FRAME];
 217         struct videobuf_queue_ops  *ops;
 218
 219         /* capture via mmap() + ioctl(QBUF/DQBUF) */
 220         unsigned int               streaming;
 221         struct list_head           stream;
 222
 223         /* capture via read() */
 224         unsigned int               reading;
 225         unsigned int               read_off;
 226         struct videobuf_buffer     *read_buf;
 227
 228         /* driver private data */
 229         void                       *priv_data;
 230 };
 231
 232 void* videobuf_alloc(unsigned int size);
 233 int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr);
 234 int videobuf_iolock(struct videobuf_queue* q, struct videobuf_buffer *vb,
 235                 struct v4l2_framebuffer *fbuf);
 236
 237 /* Maps fops to PCI stuff */
 238 void videobuf_queue_pci(struct videobuf_queue* q);
 239
 240 void videobuf_queue_init(struct videobuf_queue *q,
 241                          struct videobuf_queue_ops *ops,
 242                          void *dev,
 243                          spinlock_t *irqlock,
 244                          enum v4l2_buf_type type,
 245                          enum v4l2_field field,
 246                          unsigned int msize,
 247                          void *priv);
 248 int  videobuf_queue_is_busy(struct videobuf_queue *q);
 249 void videobuf_queue_cancel(struct videobuf_queue *q);
 250
 251 enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
 252 void videobuf_status(struct v4l2_buffer *b, struct videobuf_buffer *vb,
 253                      enum v4l2_buf_type type);
 254 int videobuf_reqbufs(struct videobuf_queue *q,
 255                      struct v4l2_requestbuffers *req);
 256 int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
 257 int videobuf_qbuf(struct videobuf_queue *q,
 258                   struct v4l2_buffer *b);
 259 int videobuf_dqbuf(struct videobuf_queue *q,
 260                    struct v4l2_buffer *b, int nonblocking);
 261 int videobuf_streamon(struct videobuf_queue *q);
 262 int videobuf_streamoff(struct videobuf_queue *q);
 263
 264 int videobuf_read_start(struct videobuf_queue *q);
 265 void videobuf_read_stop(struct videobuf_queue *q);
 266 ssize_t videobuf_read_stream(struct videobuf_queue *q,
 267                              char __user *data, size_t count, loff_t *ppos,
 268                              int vbihack, int nonblocking);
 269 ssize_t videobuf_read_one(struct videobuf_queue *q,
 270                           char __user *data, size_t count, loff_t *ppos,
 271                           int nonblocking);
 272 unsigned int videobuf_poll_stream(struct file *file,
 273                                   struct videobuf_queue *q,
 274                                   poll_table *wait);
 275
 276 int videobuf_mmap_setup(struct videobuf_queue *q,
 277                         unsigned int bcount, unsigned int bsize,
 278                         enum v4l2_memory memory);
 279 int videobuf_mmap_free(struct videobuf_queue *q);
 280 int videobuf_mmap_mapper(struct videobuf_queue *q,
 281                          struct vm_area_struct *vma);
 282
 283 /* --------------------------------------------------------------------- */
 284
 285 /*
 286  * Local variables:
 287  * c-basic-offset: 8
 288  * End:
 289  */