120 строки
3.8 KiB
C
120 строки
3.8 KiB
C
/*
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* helper functions for SG DMA video4linux capture buffers
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*
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* The functions expect the hardware being able to scatter gather
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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.
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*
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* (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
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*
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* Highly based on video-buf written originally by:
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* (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
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* (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.org>
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* (c) 2006 Ted Walther and John Sokol
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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
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*/
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#include <media/videobuf-core.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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/* --------------------------------------------------------------------- */
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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_*()
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* see Documentation/PCI/PCI-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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u32 magic;
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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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struct videobuf_dma_sg_memory
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{
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u32 magic;
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/* for mmap'ed buffers */
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struct videobuf_dmabuf dma;
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};
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void videobuf_dma_init(struct videobuf_dmabuf *dma);
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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_free(struct videobuf_dmabuf *dma);
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int videobuf_dma_map(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
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int videobuf_dma_sync(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
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int videobuf_dma_unmap(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
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struct videobuf_dmabuf *videobuf_to_dma (struct videobuf_buffer *buf);
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void *videobuf_sg_alloc(size_t size);
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void videobuf_queue_sg_init(struct videobuf_queue* q,
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const struct videobuf_queue_ops *ops,
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struct device *dev,
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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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void *priv);
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/*FIXME: these variants are used only on *-alsa code, where videobuf is
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* used without queue
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*/
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int videobuf_sg_dma_map(struct device *dev, struct videobuf_dmabuf *dma);
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int videobuf_sg_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma);
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