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426 giacomo 1
/*
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 * generic helper functions for video4linux capture buffers, to handle
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 * memory management and PCI DMA.  Right now bttv + saa7134 use it.
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 *
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 * The functions expect the hardware being able to scatter gatter
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 * (i.e. the buffers are not linear in physical memory, but fragmented
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 * into PAGE_SIZE chunks).  They also assume the driver does not need
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 * to touch the video data (thus it is probably not useful for USB as
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 * data often must be uncompressed by the drivers).
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 *
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 * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 */
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#include <linux/videodev.h>
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/* --------------------------------------------------------------------- */
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/*
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 * Return a scatterlist for some page-aligned vmalloc()'ed memory
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 * block (NULL on errors).  Memory for the scatterlist is allocated
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 * using kmalloc.  The caller must free the memory.
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 */
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struct scatterlist* videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages);
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/*
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 * Return a scatterlist for a an array of userpages (NULL on errors).
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 * Memory for the scatterlist is allocated using kmalloc.  The caller
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 * must free the memory.
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 */
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struct scatterlist* videobuf_pages_to_sg(struct page **pages, int nr_pages,
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                                         int offset);
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int videobuf_lock(struct page **pages, int nr_pages);
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int videobuf_unlock(struct page **pages, int nr_pages);
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/* --------------------------------------------------------------------- */
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/*
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 * A small set of helper functions to manage buffers (both userland
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 * and kernel) for DMA.
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 *
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 * videobuf_dma_init_*()
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 *      creates a buffer.  The userland version takes a userspace
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 *      pointer + length.  The kernel version just wants the size and
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 *      does memory allocation too using vmalloc_32().
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 *
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 * videobuf_dma_pci_*()
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 *      see Documentation/DMA-mapping.txt, these functions to
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 *      basically the same.  The map function does also build a
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 *      scatterlist for the buffer (and unmap frees it ...)
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 *
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 * videobuf_dma_free()
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 *      no comment ...
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 *
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 */
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struct videobuf_dmabuf {
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        /* for userland buffer */
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        int                 offset;
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        struct page         **pages;
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        /* for kernel buffers */
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        void                *vmalloc;
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        /* for overlay buffers (pci-pci dma) */
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        dma_addr_t          bus_addr;
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        /* common */
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        struct scatterlist  *sglist;
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        int                 sglen;
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        int                 nr_pages;
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        int                 direction;
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};
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int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
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                           unsigned long data, unsigned long size);
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int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
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                             int nr_pages);
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int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
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                              dma_addr_t addr, int nr_pages);
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int videobuf_dma_pci_map(struct pci_dev *dev, struct videobuf_dmabuf *dma);
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int videobuf_dma_pci_sync(struct pci_dev *dev,
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                          struct videobuf_dmabuf *dma);
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int videobuf_dma_pci_unmap(struct pci_dev *dev, struct videobuf_dmabuf *dma);
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int videobuf_dma_free(struct videobuf_dmabuf *dma);
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/* --------------------------------------------------------------------- */
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/*
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 * A small set of helper functions to manage video4linux buffers.
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 *
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 * struct videobuf_buffer holds the data structures used by the helper
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 * functions, additionally some commonly used fields for v4l buffers
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 * (width, height, lists, waitqueue) are in there.  That struct should
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 * be used as first element in the drivers buffer struct.
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 *
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 * about the mmap helpers (videobuf_mmap_*):
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 *
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 * The mmaper function allows to map any subset of contingous buffers.
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 * This includes one mmap() call for all buffers (which the original
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 * video4linux API uses) as well as one mmap() for every single buffer
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 * (which v4l2 uses).
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 *
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 * If there is a valid mapping for a buffer, buffer->baddr/bsize holds
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 * userspace address + size which can be feeded into the
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 * videobuf_dma_init_user function listed above.
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 *
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 */
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struct videobuf_buffer;
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struct videobuf_queue;
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struct videobuf_mapping {
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        unsigned int count;
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        int highmem_ok;
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        unsigned long start;
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        unsigned long end;
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        struct videobuf_queue *q;
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};
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enum videobuf_state {
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        STATE_NEEDS_INIT = 0,
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        STATE_PREPARED   = 1,
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        STATE_QUEUED     = 2,
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        STATE_ACTIVE     = 3,
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        STATE_DONE       = 4,
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        STATE_ERROR      = 5,
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        STATE_IDLE       = 6,
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};
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struct videobuf_buffer {
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        unsigned int            i;
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        /* info about the buffer */
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        unsigned int            width;
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        unsigned int            height;
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        unsigned int            bytesperline; /* use only if != 0 */
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        unsigned long           size;
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        enum v4l2_field         field;
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        enum videobuf_state     state;
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        struct videobuf_dmabuf  dma;
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        struct list_head        stream;  /* QBUF/DQBUF list */
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        /* for mmap'ed buffers */
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        enum v4l2_memory        memory;
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        size_t                  boff;    /* buffer offset (mmap + overlay) */
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        size_t                  bsize;   /* buffer size */
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        unsigned long           baddr;   /* buffer addr (userland ptr!) */
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        struct videobuf_mapping *map;
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        /* touched by irq handler */
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        struct list_head        queue;
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        wait_queue_head_t       done;
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        unsigned int            field_count;
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        struct timeval          ts;
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};
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struct videobuf_queue_ops {
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        int (*buf_setup)(struct file *file,
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                         unsigned int *count, unsigned int *size);
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        int (*buf_prepare)(struct file *file,struct videobuf_buffer *vb,
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                           enum v4l2_field field);
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        void (*buf_queue)(struct file *file,struct videobuf_buffer *vb);
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        void (*buf_release)(struct file *file,struct videobuf_buffer *vb);
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};
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struct videobuf_queue {
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        struct semaphore           lock;
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        spinlock_t                 *irqlock;
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        struct pci_dev             *pci;
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        enum v4l2_buf_type         type;
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        unsigned int               msize;
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        enum v4l2_field            field;
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        enum v4l2_field            last; /* for field=V4L2_FIELD_ALTERNATE */
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        struct videobuf_buffer     *bufs[VIDEO_MAX_FRAME];
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        struct videobuf_queue_ops  *ops;
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        /* capture via mmap() + ioctl(QBUF/DQBUF) */
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        unsigned int               streaming;
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        struct list_head           stream;
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        /* capture via read() */
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        unsigned int               reading;
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        unsigned int               read_off;
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        struct videobuf_buffer     *read_buf;
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};
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void* videobuf_alloc(unsigned int size);
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int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr);
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int videobuf_iolock(struct pci_dev *pci, struct videobuf_buffer *vb,
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                    struct v4l2_framebuffer *fbuf);
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void videobuf_queue_init(struct videobuf_queue *q,
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                         struct videobuf_queue_ops *ops,
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                         struct pci_dev *pci, spinlock_t *irqlock,
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                         enum v4l2_buf_type type,
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                         enum v4l2_field field,
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                         unsigned int msize);
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int  videobuf_queue_is_busy(struct videobuf_queue *q);
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void videobuf_queue_cancel(struct file *file, struct videobuf_queue *q);
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enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
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void videobuf_status(struct v4l2_buffer *b, struct videobuf_buffer *vb,
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                     enum v4l2_buf_type type);
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int videobuf_reqbufs(struct file *file, struct videobuf_queue *q,
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                     struct v4l2_requestbuffers *req);
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int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
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int videobuf_qbuf(struct file *file, struct videobuf_queue *q,
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                  struct v4l2_buffer *b);
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int videobuf_dqbuf(struct file *file, struct videobuf_queue *q,
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                   struct v4l2_buffer *b);
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int videobuf_streamon(struct file *file, struct videobuf_queue *q);
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int videobuf_streamoff(struct file *file, struct videobuf_queue *q);
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int videobuf_read_start(struct file *file, struct videobuf_queue *q);
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void videobuf_read_stop(struct file *file, struct videobuf_queue *q);
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ssize_t videobuf_read_stream(struct file *file, struct videobuf_queue *q,
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                             char *data, size_t count, loff_t *ppos,
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                             int vbihack);
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ssize_t videobuf_read_one(struct file *file, struct videobuf_queue *q,
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                          char *data, size_t count, loff_t *ppos);
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unsigned int videobuf_poll_stream(struct file *file,
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                                  struct videobuf_queue *q,
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                                  poll_table *wait);
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int videobuf_mmap_setup(struct file *file, struct videobuf_queue *q,
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                        unsigned int bcount, unsigned int bsize,
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                        enum v4l2_memory memory);
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int videobuf_mmap_free(struct file *file, struct videobuf_queue *q);
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int videobuf_mmap_mapper(struct vm_area_struct *vma,
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                         struct videobuf_queue *q);
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/* --------------------------------------------------------------------- */
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/*
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 * Local variables:
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 * c-basic-offset: 8
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 * End:
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 */