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/*
 * generic helper functions for video4linux capture buffers, to handle
 * memory management and PCI DMA.  Right now bttv + saa7134 use it.
 *
 * The functions expect the hardware being able to scatter gatter
 * (i.e. the buffers are not linear in physical memory, but fragmented
 * into PAGE_SIZE chunks).  They also assume the driver does not need
 * to touch the video data (thus it is probably not useful for USB as
 * data often must be uncompressed by the drivers).
 *
 * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */


#include <linux/videodev.h>

/* --------------------------------------------------------------------- */

/*
 * Return a scatterlist for some page-aligned vmalloc()'ed memory
 * block (NULL on errors).  Memory for the scatterlist is allocated
 * using kmalloc.  The caller must free the memory.
 */

struct scatterlist* videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages);

/*
 * Return a scatterlist for a an array of userpages (NULL on errors).
 * Memory for the scatterlist is allocated using kmalloc.  The caller
 * must free the memory.
 */

struct scatterlist* videobuf_pages_to_sg(struct page **pages, int nr_pages,
                                         int offset);
int videobuf_lock(struct page **pages, int nr_pages);
int videobuf_unlock(struct page **pages, int nr_pages);

/* --------------------------------------------------------------------- */

/*
 * A small set of helper functions to manage buffers (both userland
 * and kernel) for DMA.
 *
 * videobuf_dma_init_*()
 *      creates a buffer.  The userland version takes a userspace
 *      pointer + length.  The kernel version just wants the size and
 *      does memory allocation too using vmalloc_32().
 *
 * videobuf_dma_pci_*()
 *      see Documentation/DMA-mapping.txt, these functions to
 *      basically the same.  The map function does also build a
 *      scatterlist for the buffer (and unmap frees it ...)
 *
 * videobuf_dma_free()
 *      no comment ...
 *
 */


struct videobuf_dmabuf {
        /* for userland buffer */
        int                 offset;
        struct page         **pages;

        /* for kernel buffers */
        void                *vmalloc;

        /* for overlay buffers (pci-pci dma) */
        dma_addr_t          bus_addr;

        /* common */
        struct scatterlist  *sglist;
        int                 sglen;
        int                 nr_pages;
        int                 direction;
};

int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
                           unsigned long data, unsigned long size);
int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
                             int nr_pages);
int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
                              dma_addr_t addr, int nr_pages);
int videobuf_dma_pci_map(struct pci_dev *dev, struct videobuf_dmabuf *dma);
int videobuf_dma_pci_sync(struct pci_dev *dev,
                          struct videobuf_dmabuf *dma);
int videobuf_dma_pci_unmap(struct pci_dev *dev, struct videobuf_dmabuf *dma);
int videobuf_dma_free(struct videobuf_dmabuf *dma);

/* --------------------------------------------------------------------- */

/*
 * A small set of helper functions to manage video4linux buffers.
 *
 * struct videobuf_buffer holds the data structures used by the helper
 * functions, additionally some commonly used fields for v4l buffers
 * (width, height, lists, waitqueue) are in there.  That struct should
 * be used as first element in the drivers buffer struct.
 *
 * about the mmap helpers (videobuf_mmap_*):
 *
 * The mmaper function allows to map any subset of contingous buffers.
 * This includes one mmap() call for all buffers (which the original
 * video4linux API uses) as well as one mmap() for every single buffer
 * (which v4l2 uses).
 *
 * If there is a valid mapping for a buffer, buffer->baddr/bsize holds
 * userspace address + size which can be feeded into the
 * videobuf_dma_init_user function listed above.
 *
 */


struct videobuf_buffer;
struct videobuf_queue;

struct videobuf_mapping {
        unsigned int count;
        int highmem_ok;
        unsigned long start;
        unsigned long end;
        struct videobuf_queue *q;
};

enum videobuf_state {
        STATE_NEEDS_INIT = 0,
        STATE_PREPARED   = 1,
        STATE_QUEUED     = 2,
        STATE_ACTIVE     = 3,
        STATE_DONE       = 4,
        STATE_ERROR      = 5,
        STATE_IDLE       = 6,
};

struct videobuf_buffer {
        unsigned int            i;

        /* info about the buffer */
        unsigned int            width;
        unsigned int            height;
        unsigned int            bytesperline; /* use only if != 0 */
        unsigned long           size;
        enum v4l2_field         field;
        enum videobuf_state     state;
        struct videobuf_dmabuf  dma;
        struct list_head        stream;  /* QBUF/DQBUF list */

        /* for mmap'ed buffers */
        enum v4l2_memory        memory;
        size_t                  boff;    /* buffer offset (mmap + overlay) */
        size_t                  bsize;   /* buffer size */
        unsigned long           baddr;   /* buffer addr (userland ptr!) */
        struct videobuf_mapping *map;

        /* touched by irq handler */
        struct list_head        queue;
        wait_queue_head_t       done;
        unsigned int            field_count;
        struct timeval          ts;
};

struct videobuf_queue_ops {
        int (*buf_setup)(struct file *file,
                         unsigned int *count, unsigned int *size);
        int (*buf_prepare)(struct file *file,struct videobuf_buffer *vb,
                           enum v4l2_field field);
        void (*buf_queue)(struct file *file,struct videobuf_buffer *vb);
        void (*buf_release)(struct file *file,struct videobuf_buffer *vb);
};

struct videobuf_queue {
        struct semaphore           lock;
        spinlock_t                 *irqlock;
        struct pci_dev             *pci;

        enum v4l2_buf_type         type;
        unsigned int               msize;
        enum v4l2_field            field;
        enum v4l2_field            last; /* for field=V4L2_FIELD_ALTERNATE */
        struct videobuf_buffer     *bufs[VIDEO_MAX_FRAME];
        struct videobuf_queue_ops  *ops;

        /* capture via mmap() + ioctl(QBUF/DQBUF) */
        unsigned int               streaming;
        struct list_head           stream;

        /* capture via read() */
        unsigned int               reading;
        unsigned int               read_off;
        struct videobuf_buffer     *read_buf;
};

void* videobuf_alloc(unsigned int size);
int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr);
int videobuf_iolock(struct pci_dev *pci, struct videobuf_buffer *vb,
                    struct v4l2_framebuffer *fbuf);

void videobuf_queue_init(struct videobuf_queue *q,
                         struct videobuf_queue_ops *ops,
                         struct pci_dev *pci, spinlock_t *irqlock,
                         enum v4l2_buf_type type,
                         enum v4l2_field field,
                         unsigned int msize);
int  videobuf_queue_is_busy(struct videobuf_queue *q);
void videobuf_queue_cancel(struct file *file, struct videobuf_queue *q);

enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
void videobuf_status(struct v4l2_buffer *b, struct videobuf_buffer *vb,
                     enum v4l2_buf_type type);
int videobuf_reqbufs(struct file *file, struct videobuf_queue *q,
                     struct v4l2_requestbuffers *req);
int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
int videobuf_qbuf(struct file *file, struct videobuf_queue *q,
                  struct v4l2_buffer *b);
int videobuf_dqbuf(struct file *file, struct videobuf_queue *q,
                   struct v4l2_buffer *b);
int videobuf_streamon(struct file *file, struct videobuf_queue *q);
int videobuf_streamoff(struct file *file, struct videobuf_queue *q);

int videobuf_read_start(struct file *file, struct videobuf_queue *q);
void videobuf_read_stop(struct file *file, struct videobuf_queue *q);
ssize_t videobuf_read_stream(struct file *file, struct videobuf_queue *q,
                             char *data, size_t count, loff_t *ppos,
                             int vbihack);
ssize_t videobuf_read_one(struct file *file, struct videobuf_queue *q,
                          char *data, size_t count, loff_t *ppos);
unsigned int videobuf_poll_stream(struct file *file,
                                  struct videobuf_queue *q,
                                  poll_table *wait);

int videobuf_mmap_setup(struct file *file, struct videobuf_queue *q,
                        unsigned int bcount, unsigned int bsize,
                        enum v4l2_memory memory);
int videobuf_mmap_free(struct file *file, struct videobuf_queue *q);
int videobuf_mmap_mapper(struct vm_area_struct *vma,
                         struct videobuf_queue *q);

/* --------------------------------------------------------------------- */

/*
 * Local variables:
 * c-basic-offset: 8
 * End:
 */