media: videobuf2: handle V4L2_MEMORY_FLAG_NON_COHERENT flag

This patch lets user-space request a non-coherent memory allocation during CREATE_BUFS and REQBUFS ioctl calls. = CREATE_BUFS struct v4l2_create_buffers has seven 4-byte reserved areas, so reserved[0] is renamed to ->flags. The struct, thus, now has six reserved 4-byte regions. = CREATE_BUFS32 struct v4l2_create_buffers32 has seven 4-byte reserved areas, so reserved[0] is renamed to ->flags. The struct, thus, now has six reserved 4-byte regions. = REQBUFS We use one byte of a 4 byte ->reserved[1] member of struct v4l2_requestbuffers. The struct, thus, now has reserved 3 bytes.

Sergey Senozhatsky committed 5 years ago

Commit c0acf9c1 parent b00a9e57 files · +60 −15Browse files

Showing the changes to include/uapi (1 of 7 files). Show all

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include/uapi/linux/videodev2.h+7−2

@@ -959,7 +959,8 @@ struct v4l2_requestbuffers { · 958 unmodified lines
959	959	__u32 type; /* enum v4l2_buf_type */
960	960	__u32 memory; /* enum v4l2_memory */
961	961	__u32 capabilities;
962		− __u32 reserved[1];
	962	+ __u8 flags;
	963	+ __u8 reserved[3];
963	964	};
964	965
965	966	#define V4L2_MEMORY_FLAG_NON_COHERENT (1 << 0)
@@ -2507,6 +2508,9 @@ struct v4l2_dbg_chip_info { · 1541 unmodified lines
2507	2508	* @memory: enum v4l2_memory; buffer memory type
2508	2509	* @format: frame format, for which buffers are requested
2509	2510	* @capabilities: capabilities of this buffer type.
	2511	+ * @flags: additional buffer management attributes (ignored unless the
	2512	+ * queue has V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS capability
	2513	+ * and configured for MMAP streaming I/O).
2510	2514	* @reserved: future extensions
2511	2515	*/
2512	2516	struct v4l2_create_buffers {
@@ -2515,7 +2519,8 @@ struct v4l2_create_buffers { · 2 unmodified lines
2515	2519	__u32 memory;
2516	2520	struct v4l2_format format;
2517	2521	__u32 capabilities;
2518		− __u32 reserved[7];
	2522	+ __u32 flags;
	2523	+ __u32 reserved[6];
2519	2524	};
2520	2525
2521	2526	/*