/* * 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@infradead.org> * * Highly based on video-buf written originally by: * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org> * (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.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 */ #include <media/videobuf-core.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); /* --------------------------------------------------------------------- */ /* * 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-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 { u32 magic; /* 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; }; struct videobuf_dma_sg_memory { u32 magic; /* for mmap'ed buffers */ struct videobuf_dmabuf dma; }; void videobuf_dma_init(struct videobuf_dmabuf *dma); 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_free(struct videobuf_dmabuf *dma); int videobuf_dma_map(struct videobuf_queue* q,struct videobuf_dmabuf *dma); int videobuf_dma_sync(struct videobuf_queue* q,struct videobuf_dmabuf *dma); int videobuf_dma_unmap(struct videobuf_queue* q,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, 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); /*FIXME: these variants are used only on *-alsa code, where videobuf is * used without queue */ int videobuf_sg_dma_map(struct device *dev, struct videobuf_dmabuf *dma); int videobuf_sg_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma);