77512baaea
Based on 1 normalized pattern(s): 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 8 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190602204654.096873163@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
103 lines
2.8 KiB
C
103 lines
2.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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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@kernel.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@kernel.org>
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* (c) 2006 Ted Walther and John Sokol
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*/
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#ifndef _VIDEOBUF_DMA_SG_H
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#define _VIDEOBUF_DMA_SG_H
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#include <media/videobuf-core.h>
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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/DMA-API-HOWTO.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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size_t size;
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struct page **pages;
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/* for kernel buffers */
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void *vaddr;
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struct page **vaddr_pages;
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dma_addr_t *dma_addr;
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struct device *dev;
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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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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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/*
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* Scatter-gather DMA buffer API.
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*
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* These functions provide a simple way to create a page list and a
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* scatter-gather list from a kernel, userspace of physical address and map the
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* memory for DMA operation.
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*
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* Despite the name, this is totally unrelated to videobuf, except that
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* videobuf-dma-sg uses the same API internally.
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*/
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int videobuf_dma_free(struct videobuf_dmabuf *dma);
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int videobuf_dma_unmap(struct device *dev, 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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struct mutex *ext_lock);
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#endif /* _VIDEOBUF_DMA_SG_H */
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