Create controls for Nuvoton NPCM video driver to support setting capture mode of Video Capture/Differentiation (VCD) engine and getting the count of HEXTILE rectangles that is compressed by Encoding Compression Engine (ECE). Signed-off-by: Marvin Lin <milkfafa@xxxxxxxxx> --- .../userspace-api/media/drivers/index.rst | 1 + .../media/drivers/npcm-video.rst | 67 +++++++++++++++++++ include/uapi/linux/npcm-video.h | 41 ++++++++++++ 3 files changed, 109 insertions(+) create mode 100644 Documentation/userspace-api/media/drivers/npcm-video.rst create mode 100644 include/uapi/linux/npcm-video.h diff --git a/Documentation/userspace-api/media/drivers/index.rst b/Documentation/userspace-api/media/drivers/index.rst index 915dbf0f4db5..97d2ce8da6b3 100644 --- a/Documentation/userspace-api/media/drivers/index.rst +++ b/Documentation/userspace-api/media/drivers/index.rst @@ -38,6 +38,7 @@ For more details see the file COPYING in the source distribution of Linux. imx-uapi max2175 meye-uapi + npcm-video omap3isp-uapi st-vgxy61 uvcvideo diff --git a/Documentation/userspace-api/media/drivers/npcm-video.rst b/Documentation/userspace-api/media/drivers/npcm-video.rst new file mode 100644 index 000000000000..eccbba0d7351 --- /dev/null +++ b/Documentation/userspace-api/media/drivers/npcm-video.rst @@ -0,0 +1,67 @@ +.. SPDX-License-Identifier: GPL-2.0 + +.. include:: <isonum.txt> + +NPCM video driver +================= + +This driver is used to control the Video Capture/Differentiation (VCD) engine +and Encoding Compression Engine (ECE) present on Nuvoton NPCM SoCs. The VCD can +capture a frame from digital video input and compare two frames in memory, then +the ECE will compress the frame data into HEXTILE format. + +Driver-specific Controls +------------------------ + +V4L2_CID_NPCM_CAPTURE_MODE +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The VCD engine supports two modes: + +- COMPLETE mode: + + Capture the next complete frame into memory. + +- DIFF mode: + + Compare the incoming frame with the frame stored in memory, and updates the + differentiated frame in memory. + +Application can use ``V4L2_CID_NPCM_CAPTURE_MODE`` control to set the VCD mode +with different control values (enum v4l2_npcm_capture_mode): + +- ``V4L2_NPCM_CAPTURE_MODE_COMPLETE``: will set VCD to COMPLETE mode. +- ``V4L2_NPCM_CAPTURE_MODE_DIFF``: will set VCD to DIFF mode. + +V4L2_CID_NPCM_RECT_COUNT +~~~~~~~~~~~~~~~~~~~~~~~~ + +After frame data is captured, the ECE will compress the data into HEXTILE format +and store these HEXTILE rectangles data in V4L2 video buffer with the layout +defined in Remote Framebuffer Protocol: +:: + + (RFC 6143, https://www.rfc-editor.org/rfc/rfc6143.html#section-7.6.1) + + +--------------+--------------+-------------------+ + | No. of bytes | Type [Value] | Description | + +--------------+--------------+-------------------+ + | 2 | U16 | x-position | + | 2 | U16 | y-position | + | 2 | U16 | width | + | 2 | U16 | height | + | 4 | S32 | encoding-type (5) | + +--------------+--------------+-------------------+ + | HEXTILE rectangle data | + +-------------------------------------------------+ + +Application can get these video buffers through V4L2 interfaces and use +``V4L2_CID_NPCM_RECT_COUNT`` control to get the count of compressed HEXTILE +rectangles that can be put in the field number-of-rectangles of +FramebufferUpdate header. + +References +---------- +include/uapi/linux/npcm-video.h + +**Copyright** |copy| 2022 Nuvoton Technologies diff --git a/include/uapi/linux/npcm-video.h b/include/uapi/linux/npcm-video.h new file mode 100644 index 000000000000..1d39f6f38c96 --- /dev/null +++ b/include/uapi/linux/npcm-video.h @@ -0,0 +1,41 @@ +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */ +/* + * Controls header for NPCM video driver + * + * Copyright (C) 2022 Nuvoton Technologies + */ + +#ifndef _UAPI_LINUX_NPCM_VIDEO_H +#define _UAPI_LINUX_NPCM_VIDEO_H + +#include <linux/v4l2-controls.h> + +/* + * Check Documentation/userspace-api/media/drivers/npcm-video.rst for control + * details. + */ + +/* + * This control is meant to set the mode of NPCM Video Capture/Differentiation + * (VCD) engine. + * + * The VCD engine supports two modes: + * COMPLETE - Capture the next complete frame into memory. + * DIFF - Compare the incoming frame with the frame stored in memory, and + * updates the differentiated frame in memory. + */ +#define V4L2_CID_NPCM_CAPTURE_MODE (V4L2_CID_USER_NPCM_BASE + 0) + +enum v4l2_npcm_capture_mode { + V4L2_NPCM_CAPTURE_MODE_COMPLETE = 0, /* COMPLETE mode */ + V4L2_NPCM_CAPTURE_MODE_DIFF = 1, /* DIFF mode */ +}; + +/* + * This control is meant to get the count of compressed HEXTILE rectangles which + * is relevant to the number of differentiated frames if VCD is in DIFF mode. + * And the count will always be 1 if VCD is in COMPLETE mode. + */ +#define V4L2_CID_NPCM_RECT_COUNT (V4L2_CID_USER_NPCM_BASE + 1) + +#endif /* _UAPI_LINUX_NPCM_VIDEO_H */ -- 2.34.1
