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Diffstat (limited to '')
| -rw-r--r-- | include/media/videobuf-dma-sg.h | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/include/media/videobuf-dma-sg.h b/include/media/videobuf-dma-sg.h new file mode 100644 index 000000000..01bd142b9 --- /dev/null +++ b/include/media/videobuf-dma-sg.h @@ -0,0 +1,105 @@ +/* + * helper functions for SG DMA video4linux capture buffers + * + * The functions expect the hardware being able to scatter gather + * (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. + * + * (c) 2007 Mauro Carvalho Chehab, <mchehab@kernel.org> + * + * Highly based on video-buf written originally by: + * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org> + * (c) 2006 Mauro Carvalho Chehab, <mchehab@kernel.org> + * (c) 2006 Ted Walther and John Sokol + * + * 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 + */ +#ifndef _VIDEOBUF_DMA_SG_H +#define _VIDEOBUF_DMA_SG_H + +#include <media/videobuf-core.h> + +/* --------------------------------------------------------------------- */ + +/* + * 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_*() + * see Documentation/DMA-API-HOWTO.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 { + u32 magic; + + /* for userland buffer */ + int offset; + size_t size; + struct page **pages; + + /* for kernel buffers */ + void *vaddr; + struct page **vaddr_pages; + dma_addr_t *dma_addr; + struct device *dev; + + /* for overlay buffers (pci-pci dma) */ + dma_addr_t bus_addr; + + /* common */ + struct scatterlist *sglist; + int sglen; + int nr_pages; + int direction; +}; + +struct videobuf_dma_sg_memory { + u32 magic; + + /* for mmap'ed buffers */ + struct videobuf_dmabuf dma; +}; + +/* + * Scatter-gather DMA buffer API. + * + * These functions provide a simple way to create a page list and a + * scatter-gather list from a kernel, userspace of physical address and map the + * memory for DMA operation. + * + * Despite the name, this is totally unrelated to videobuf, except that + * videobuf-dma-sg uses the same API internally. + */ +int videobuf_dma_free(struct videobuf_dmabuf *dma); + +int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma); +struct videobuf_dmabuf *videobuf_to_dma(struct videobuf_buffer *buf); + +void *videobuf_sg_alloc(size_t size); + +void videobuf_queue_sg_init(struct videobuf_queue *q, + const struct videobuf_queue_ops *ops, + struct device *dev, + spinlock_t *irqlock, + enum v4l2_buf_type type, + enum v4l2_field field, + unsigned int msize, + void *priv, + struct mutex *ext_lock); + +#endif /* _VIDEOBUF_DMA_SG_H */ + |