1 files changed, 102 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..930ff8d45
--- /dev/null
+++ b/include/media/videobuf-dma-sg.h
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * 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
+ */
+#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/core-api/dma-api-howto.rst, 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;
+	unsigned long       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 */
+