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         /* for overlay buffers (pci-pci dma) */
  82         dma_addr_t          bus_addr;
  83
  84         /* common */
  85         struct scatterlist  *sglist;
  86         int                 sglen;
  87         int                 nr_pages;
  88         int                 direction;
  89 };
  90
  91 void videobuf_dma_init(struct videobuf_dmabuf *dma);
  92 int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
  93                            unsigned long data, unsigned long size);
  94 int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
  95                              int nr_pages);
  96 int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
  97                               dma_addr_t addr, int nr_pages);
  98 int videobuf_dma_free(struct videobuf_dmabuf *dma);
  99
 100 int videobuf_dma_map(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
 101 int videobuf_dma_sync(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
 102 int videobuf_dma_unmap(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
 103
 104         /*FIXME: these variants are used only on *-alsa code, where videobuf is
 105          * used without queue
 106          */
 107 int videobuf_pci_dma_map(struct pci_dev *pci,struct videobuf_dmabuf *dma);
 108 int videobuf_pci_dma_unmap(struct pci_dev *pci,struct videobuf_dmabuf *dma);
 109
 110 /* --------------------------------------------------------------------- */
 111
 112 /*
 113  * A small set of helper functions to manage video4linux buffers.
 114  *
 115  * struct videobuf_buffer holds the data structures used by the helper
 116  * functions, additionally some commonly used fields for v4l buffers
 117  * (width, height, lists, waitqueue) are in there.  That struct should
 118  * be used as first element in the drivers buffer struct.
 119  *
 120  * about the mmap helpers (videobuf_mmap_*):
 121  *
 122  * The mmaper function allows to map any subset of contingous buffers.
 123  * This includes one mmap() call for all buffers (which the original
 124  * video4linux API uses) as well as one mmap() for every single buffer
 125  * (which v4l2 uses).
 126  *
 127  * If there is a valid mapping for a buffer, buffer->baddr/bsize holds
 128  * userspace address + size which can be feeded into the
 129  * videobuf_dma_init_user function listed above.
 130  *
 131  */
 132
 133 struct videobuf_mapping {
 134         unsigned int count;
 135         unsigned long start;
 136         unsigned long end;
 137         struct videobuf_queue *q;
 138 };
 139
 140 enum videobuf_state {
 141         STATE_NEEDS_INIT = 0,
 142         STATE_PREPARED   = 1,
 143         STATE_QUEUED     = 2,
 144         STATE_ACTIVE     = 3,
 145         STATE_DONE       = 4,
 146         STATE_ERROR      = 5,
 147         STATE_IDLE       = 6,
 148 };
 149
 150 struct videobuf_buffer {
 151         unsigned int            i;
 152         u32                     magic;
 153
 154         /* info about the buffer */
 155         unsigned int            width;
 156         unsigned int            height;
 157         unsigned int            bytesperline; /* use only if != 0 */
 158         unsigned long           size;
 159         unsigned int            input;
 160         enum v4l2_field         field;
 161         enum videobuf_state     state;
 162         struct videobuf_dmabuf  dma;
 163         struct list_head        stream;  /* QBUF/DQBUF list */
 164
 165         /* for mmap'ed buffers */
 166         enum v4l2_memory        memory;
 167         size_t                  boff;    /* buffer offset (mmap + overlay) */
 168         size_t                  bsize;   /* buffer size */
 169         unsigned long           baddr;   /* buffer addr (userland ptr!) */
 170         struct videobuf_mapping *map;
 171
 172         /* touched by irq handler */
 173         struct list_head        queue;
 174         wait_queue_head_t       done;
 175         unsigned int            field_count;
 176         struct timeval          ts;
 177 };
 178
 179 typedef int (vb_map_sg_t)(void *dev,struct scatterlist *sglist,int nr_pages,
 180                                         int direction);
 181
 182
 183 struct videobuf_queue_ops {
 184         int (*buf_setup)(struct videobuf_queue *q,
 185                          unsigned int *count, unsigned int *size);
 186         int (*buf_prepare)(struct videobuf_queue *q,
 187                            struct videobuf_buffer *vb,
 188                            enum v4l2_field field);
 189         void (*buf_queue)(struct videobuf_queue *q,
 190                           struct videobuf_buffer *vb);
 191         void (*buf_release)(struct videobuf_queue *q,
 192                             struct videobuf_buffer *vb);
 193
 194         /* Helper operations - device dependent.
 195          * If null, videobuf_init defaults all to PCI handling
 196          */
 197
 198         vb_map_sg_t     *vb_map_sg;
 199         vb_map_sg_t     *vb_dma_sync_sg;
 200         vb_map_sg_t     *vb_unmap_sg;
 201 };
 202
 203 struct videobuf_queue {
 204         struct mutex               lock;
 205         spinlock_t                 *irqlock;
 206         void                       *dev; /* on pci, points to struct pci_dev */
 207
 208         enum v4l2_buf_type         type;
 209         unsigned int               inputs; /* for V4L2_BUF_FLAG_INPUT */
 210         unsigned int               msize;
 211         enum v4l2_field            field;
 212         enum v4l2_field            last;   /* for field=V4L2_FIELD_ALTERNATE */
 213         struct videobuf_buffer     *bufs[VIDEO_MAX_FRAME];
 214         struct videobuf_queue_ops  *ops;
 215
 216         /* capture via mmap() + ioctl(QBUF/DQBUF) */
 217         unsigned int               streaming;
 218         struct list_head           stream;
 219
 220         /* capture via read() */
 221         unsigned int               reading;
 222         unsigned int               read_off;
 223         struct videobuf_buffer     *read_buf;
 224
 225         /* driver private data */
 226         void                       *priv_data;
 227 };
 228
 229 void* videobuf_alloc(unsigned int size);
 230 int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr);
 231 int videobuf_iolock(struct videobuf_queue* q, struct videobuf_buffer *vb,
 232                 struct v4l2_framebuffer *fbuf);
 233
 234 /* Maps fops to PCI stuff */
 235 void videobuf_queue_pci(struct videobuf_queue* q);
 236
 237 void videobuf_queue_init(struct videobuf_queue *q,
 238                          struct videobuf_queue_ops *ops,
 239                          void *dev,
 240                          spinlock_t *irqlock,
 241                          enum v4l2_buf_type type,
 242                          enum v4l2_field field,
 243                          unsigned int msize,
 244                          void *priv);
 245 int  videobuf_queue_is_busy(struct videobuf_queue *q);
 246 void videobuf_queue_cancel(struct videobuf_queue *q);
 247
 248 enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
 249 void videobuf_status(struct v4l2_buffer *b, struct videobuf_buffer *vb,
 250                      enum v4l2_buf_type type);
 251 int videobuf_reqbufs(struct videobuf_queue *q,
 252                      struct v4l2_requestbuffers *req);
 253 int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
 254 int videobuf_qbuf(struct videobuf_queue *q,
 255                   struct v4l2_buffer *b);
 256 int videobuf_dqbuf(struct videobuf_queue *q,
 257                    struct v4l2_buffer *b, int nonblocking);
 258 int videobuf_streamon(struct videobuf_queue *q);
 259 int videobuf_streamoff(struct videobuf_queue *q);
 260
 261 int videobuf_read_start(struct videobuf_queue *q);
 262 void videobuf_read_stop(struct videobuf_queue *q);
 263 ssize_t videobuf_read_stream(struct videobuf_queue *q,
 264                              char __user *data, size_t count, loff_t *ppos,
 265                              int vbihack, int nonblocking);
 266 ssize_t videobuf_read_one(struct videobuf_queue *q,
 267                           char __user *data, size_t count, loff_t *ppos,
 268                           int nonblocking);
 269 unsigned int videobuf_poll_stream(struct file *file,
 270                                   struct videobuf_queue *q,
 271                                   poll_table *wait);
 272
 273 int videobuf_mmap_setup(struct videobuf_queue *q,
 274                         unsigned int bcount, unsigned int bsize,
 275                         enum v4l2_memory memory);
 276 int videobuf_mmap_free(struct videobuf_queue *q);
 277 int videobuf_mmap_mapper(struct videobuf_queue *q,
 278                          struct vm_area_struct *vma);
 279
 280 /* --------------------------------------------------------------------- */
 281
 282 /*
 283  * Local variables:
 284  * c-basic-offset: 8
 285  * End:
 286  */