From patchwork Tue Jul 9 13:28:56 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Scally X-Patchwork-Id: 811991 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9B0EE161B43; Tue, 9 Jul 2024 13:29:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720531774; cv=none; b=L/kYFPpK6JHjzWO1ZQsmc5QJn+3556YxDIhhTRIPQg6fHgGzBMjuXNAJ/f2O7r810vN2oozbkrdSZcFE64Br0+fHa1AgiPI+X/eWlllq73aFvUGpuYVMpj/SOpMJ8uspm4dF/BWL83Kl88Y/4j5Yp7H1/ta82L5Z5v8FEhdZuXI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720531774; c=relaxed/simple; bh=vkswc81xlr3zpJPWk7XI11qxjtfBw7Z85nMrgNDERUY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=f/IB+/mF1/ft6uL9O3xiinNiNGeazBHpLJc4l8jrgE4MA428hX9gP7GVUi9fE1fOmK6491LtB3HJktE60jNRuU/kX4KScroiR/bdy2a2NTMEm5FMdKqfE/hZmr1QM/WZmFWToKALFcYr8rxXbClDm8aAHGggjWCXLbPnDF4fmPw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=WiuTWsvS; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="WiuTWsvS" Received: from mail.ideasonboard.com (cpc141996-chfd3-2-0-cust928.12-3.cable.virginm.net [86.13.91.161]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 1318723CE; Tue, 9 Jul 2024 15:28:48 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1720531728; bh=vkswc81xlr3zpJPWk7XI11qxjtfBw7Z85nMrgNDERUY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WiuTWsvSZ/+KLAM9aHrndcZTs8tNsmhCIZCGtujTtyLNRi/K0y+3U83Y/Ct07Wjvj 1UjnFkq6ZFZ3H9OHZ8r5SP0ve5z5hpPiHqyuA8Fz+esG/zguK/ms++97g6T4iknN/u kuev8Gj9QLIIqdlkSIcvmOSH6Q8HCEcIBts42Dfs= From: Daniel Scally To: linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: jacopo.mondi@ideasonboard.com, nayden.kanchev@arm.com, robh+dt@kernel.org, mchehab@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, jerome.forissier@linaro.org, kieran.bingham@ideasonboard.com, laurent.pinchart@ideasonboard.com, sakari.ailus@iki.fi, Daniel Scally Subject: [PATCH v6 08/18] media: Documentation: Add Mali-C55 ISP Documentation Date: Tue, 9 Jul 2024 14:28:56 +0100 Message-Id: <20240709132906.3198927-9-dan.scally@ideasonboard.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240709132906.3198927-1-dan.scally@ideasonboard.com> References: <20240709132906.3198927-1-dan.scally@ideasonboard.com> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add a documentation page for the mali-c55 driver, which gives a brief overview of the hardware and explains how to use the driver's capture devices and the crop/scaler functions. Acked-by: Nayden Kanchev Co-developed-by: Jacopo Mondi Signed-off-by: Jacopo Mondi Signed-off-by: Daniel Scally --- Changes in v6: - Minor formatting changes Changes in v5: - None Changes in v4: - None Changes in v3: - Documented the synchronised buffer sequence numbers (Sakari) - Clarified that the downscale pipe cannot output raw data, the ISP'S resolution limits and choice of media bus format code (Kieran) Changes in v2: - none .../admin-guide/media/mali-c55-graph.dot | 19 + Documentation/admin-guide/media/mali-c55.rst | 340 ++++++++++++++++++ .../admin-guide/media/v4l-drivers.rst | 1 + 3 files changed, 360 insertions(+) create mode 100644 Documentation/admin-guide/media/mali-c55-graph.dot create mode 100644 Documentation/admin-guide/media/mali-c55.rst diff --git a/Documentation/admin-guide/media/mali-c55-graph.dot b/Documentation/admin-guide/media/mali-c55-graph.dot new file mode 100644 index 000000000000..0775ba42bf4c --- /dev/null +++ b/Documentation/admin-guide/media/mali-c55-graph.dot @@ -0,0 +1,19 @@ +digraph board { + rankdir=TB + n00000001 [label="{{} | mali-c55 tpg\n/dev/v4l-subdev0 | { 0}}", shape=Mrecord, style=filled, fillcolor=green] + n00000001:port0 -> n00000003:port0 [style=dashed] + n00000003 [label="{{ 0} | mali-c55 isp\n/dev/v4l-subdev1 | { 1 | 2}}", shape=Mrecord, style=filled, fillcolor=green] + n00000003:port1 -> n00000007:port0 [style=bold] + n00000003:port2 -> n00000007:port2 [style=bold] + n00000003:port1 -> n0000000b:port0 [style=bold] + n00000007 [label="{{ 0 | 2} | mali-c55 resizer fr\n/dev/v4l-subdev2 | { 1}}", shape=Mrecord, style=filled, fillcolor=green] + n00000007:port1 -> n0000000e [style=bold] + n0000000b [label="{{ 0} | mali-c55 resizer ds\n/dev/v4l-subdev3 | { 1}}", shape=Mrecord, style=filled, fillcolor=green] + n0000000b:port1 -> n00000012 [style=bold] + n0000000e [label="mali-c55 fr\n/dev/video0", shape=box, style=filled, fillcolor=yellow] + n00000012 [label="mali-c55 ds\n/dev/video1", shape=box, style=filled, fillcolor=yellow] + n00000022 [label="{{ 0} | csi2-rx\n/dev/v4l-subdev4 | { 1}}", shape=Mrecord, style=filled, fillcolor=green] + n00000022:port1 -> n00000003:port0 + n00000027 [label="{{} | imx415 1-001a\n/dev/v4l-subdev5 | { 0}}", shape=Mrecord, style=filled, fillcolor=green] + n00000027:port0 -> n00000022:port0 [style=bold] +} \ No newline at end of file diff --git a/Documentation/admin-guide/media/mali-c55.rst b/Documentation/admin-guide/media/mali-c55.rst new file mode 100644 index 000000000000..72cdded507b3 --- /dev/null +++ b/Documentation/admin-guide/media/mali-c55.rst @@ -0,0 +1,340 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================================== +ARM Mali-C55 Image Signal Processor driver +========================================== + +Introduction +============ + +This file documents the driver for ARM's Mali-C55 Image Signal Processor. The +driver is located under drivers/media/platform/arm/mali-c55. + +The Mali-C55 ISP receives data in either raw Bayer format or RGB/YUV format from +sensors through either a parallel interface or a memory bus before processing it +and outputting it through an internal DMA engine. Two output pipelines are +possible (though one may not be fitted, depending on the implementation). These +are referred to as "Full resolution" and "Downscale", but the naming is historic +and both pipes are capable of cropping/scaling operations. The full resolution +pipe is also capable of outputting RAW data, bypassing much of the ISP's +processing. The downscale pipe cannot output RAW data. An integrated test +pattern generator can be used to drive the ISP and produce image data in the +absence of a connected camera sensor. The driver module is named mali_c55, and +is enabled through the CONFIG_VIDEO_MALI_C55 config option. + +The driver implements V4L2, Media Controller and V4L2 Subdevice interfaces and +expects camera sensors connected to the ISP to have V4L2 subdevice interfaces. + +Mali-C55 ISP hardware +===================== + +A high level functional view of the Mali-C55 ISP is presented below. The ISP +takes input from either a live source or through a DMA engine for memory input, +depending on the SoC integration.:: + + +---------+ +----------+ +--------+ + | Sensor |--->| CSI-2 Rx | "Full Resolution" | DMA | + +---------+ +----------+ |\ Output +--->| Writer | + | | \ | +--------+ + | | \ +----------+ +------+---> Streaming I/O + +------------+ +------->| | | | | + | | | |-->| Mali-C55 |--+ + | DMA Reader |--------------->| | | ISP | | + | | | / | | | +---> Streaming I/O + +------------+ | / +----------+ | | + |/ +------+ + | +--------+ + +--->| DMA | + "Downscaled" | Writer | + Output +--------+ + +Media Controller Topology +========================= + +An example of the ISP's topology (as implemented in a system with an IMX415 +camera sensor and generic CSI-2 receiver) is below: + + +.. kernel-figure:: mali-c55-graph.dot + :alt: mali-c55-graph.dot + :align: center + +The driver has 4 V4L2 subdevices: + +- `mali_c55 isp`: Responsible for configuring input crop and color space + conversion +- `mali_c55 tpg`: The test pattern generator, emulating a camera sensor. +- `mali_c55 resizer fr`: The Full-Resolution pipe resizer +- `mali_c55 resizer ds`: The Downscale pipe resizer + +The driver has 2 V4L2 video devices: + +- `mali-c55 fr`: The full-resolution pipe's capture device +- `mali-c55 ds`: The downscale pipe's capture device + +Frame sequences are synchronised across to two capture devices, meaning if one +pipe is started later than the other the sequence numbers returned in its +buffers will match those of the other pipe rather than starting from zero. + +Idiosyncrasies +-------------- + +**mali-c55 isp** +The `mali-c55 isp` subdevice has a single sink pad to which all sources of data +should be connected. The active source is selected by enabling the appropriate +media link and disabling all others. The ISP has two source pads, reflecting the +different paths through which it can internally route data. Tap points within +the ISP allow users to divert data to avoid processing by some or all of the +hardware's processing steps. The diagram below is intended only to highlight how +the bypassing works and is not a true reflection of those processing steps; for +a high-level functional block diagram see ARM's developer page for the +ISP [3]_:: + + +--------------------------------------------------------------+ + | Possible Internal ISP Data Routes | + | +------------+ +----------+ +------------+ | + +---+ | | | | | Colour | +---+ + | 0 |--+-->| Processing |->| Demosaic |->| Space |--->| 1 | + +---+ | | | | | | Conversion | +---+ + | | +------------+ +----------+ +------------+ | + | | +---+ + | +---------------------------------------------------| 2 | + | +---+ + | | + +--------------------------------------------------------------+ + + +.. flat-table:: + :header-rows: 1 + + * - Pad + - Direction + - Purpose + + * - 0 + - sink + - Data input, connected to the TPG and camera sensors + + * - 1 + - source + - RGB/YUV data, connected to the FR and DS V4L2 subdevices + + * - 2 + - source + - RAW bayer data, connected to the FR V4L2 subdevices + +The ISP is limited to both input and output resolutions between 640x480 and +8192x8192, and this is reflected in the ISP and resizer subdevice's .set_fmt() +operations. + +**mali-c55 resizer fr** +The `mali-c55 resizer fr` subdevice has two _sink_ pads to reflect the different +insertion points in the hardware (either RAW or demosaiced data): + +.. flat-table:: + :header-rows: 1 + + * - Pad + - Direction + - Purpose + + * - 0 + - sink + - Data input connected to the ISP's demosaiced stream. + + * - 1 + - source + - Data output connected to the capture video device + + * - 2 + - sink + - Data input connected to the ISP's raw data stream + +The data source in use is selected through the routing API; two routes each of a +single stream are available: + +.. flat-table:: + :header-rows: 1 + + * - Sink Pad + - Source Pad + - Purpose + + * - 0 + - 1 + - Demosaiced data route + + * - 2 + - 1 + - Raw data route + + +If the demosaiced route is active then the FR pipe is only capable of output +in RGB/YUV formats. If the raw route is active then the output reflects the +input (which may be either Bayer or RGB/YUV data). + +Using the driver to capture video +================================= + +Using the media controller APIs we can configure the input source and ISP to +capture images in a variety of formats. In the examples below, configuring the +media graph is done with the v4l-utils [1]_ package's media-ctl utility. +Capturing the images is done with yavta [2]_. + +Configuring the input source +---------------------------- + +The first step is to set the input source that we wish by enabling the correct +media link. Using the example topology above, we can select the TPG as follows: + +.. code-block:: none + + media-ctl -l "'lte-csi2-rx':1->'mali-c55 isp':0[0]" + media-ctl -l "'mali-c55 tpg':0->'mali-c55 isp':0[1]" + +Configuring which video devices will stream data +------------------------------------------------ + +The driver will wait for all video devices to have their VIDIOC_STREAMON ioctl +called before it tells the sensor to start streaming. To facilitate this we need +to enable links to the video devices that we want to use. In the example below +we enable the links to both of the image capture video devices + +.. code-block:: none + + media-ctl -l "'mali-c55 resizer fr':1->'mali-c55 fr':0[1]" + media-ctl -l "'mali-c55 resizer ds':1->'mali-c55 ds':0[1]" + +Capturing bayer data from the source and processing to RGB/YUV +-------------------------------------------------------------- + +To capture 1920x1080 bayer data from the source and push it through the ISP's +full processing pipeline, we configure the data formats appropriately on the +source, ISP and resizer subdevices and set the FR resizer's routing to select +processed data. The media bus format on the resizer's source pad will be either +RGB121212_1X36 or YUV10_1X30, depending on whether you want to capture RGB or +YUV. The ISP's debayering block outputs RGB data natively, setting the source +pad format to YUV10_1X30 enables the colour space conversion block. + +In this example we target RGB565 output, so select RGB121212_1X36 as the resizer +source pad's format: + +.. code-block:: none + + # Set formats on the TPG and ISP + media-ctl -V "'mali-c55 tpg':0[fmt:SRGGB20_1X20/1920x1080]" + media-ctl -V "'mali-c55 isp':0[fmt:SRGGB20_1X20/1920x1080]" + media-ctl -V "'mali-c55 isp':1[fmt:SRGGB20_1X20/1920x1080]" + + # Set routing on the FR resizer + media-ctl -R "'mali-c55 resizer fr'[0/0->1/0[1],2/0->1/0[0]]" + + # Set format on the resizer, must be done AFTER the routing. + media-ctl -V "'mali-c55 resizer fr':1[fmt:RGB121212_1X36/1920x1080]" + +The downscale output can also be used to stream data at the same time. In this +case since only processed data can be captured through the downscale output no +routing need be set: + +.. code-block:: none + + # Set format on the resizer + media-ctl -V "'mali-c55 resizer ds':1[fmt:RGB121212_1X36/1920x1080]" + +Following which images can be captured from both the FR and DS output's video +devices (simultaneously, if desired): + +.. code-block:: none + + yavta -f RGB565 -s 1920x1080 -c10 /dev/video0 + yavta -f RGB565 -s 1920x1080 -c10 /dev/video1 + +Cropping the image +~~~~~~~~~~~~~~~~~~ + +Both the full resolution and downscale pipes can crop to a minimum resolution of +640x480. To crop the image simply configure the resizer's sink pad's crop and +compose rectangles and set the format on the video device: + +.. code-block:: none + + media-ctl -V "'mali-c55 resizer fr':0[fmt:RGB121212_1X36/1920x1080 crop:(480,270)/640x480 compose:(0,0)/640x480]" + media-ctl -V "'mali-c55 resizer fr':1[fmt:RGB121212_1X36/640x480]" + yavta -f RGB565 -s 640x480 -c10 /dev/video0 + +Downscaling the image +~~~~~~~~~~~~~~~~~~~~~ + +Both the full resolution and downscale pipes can downscale the image by up to 8x +provided the minimum 640x480 output resolution is adhered to. For the best image +result the scaling ratio for each direction should be the same. To configure +scaling we use the compose rectangle on the resizer's sink pad: + +.. code-block:: none + + media-ctl -V "'mali-c55 resizer fr':0[fmt:RGB121212_1X36/1920x1080 crop:(0,0)/1920x1080 compose:(0,0)/640x480]" + media-ctl -V "'mali-c55 resizer fr':1[fmt:RGB121212_1X36/640x480]" + yavta -f RGB565 -s 640x480 -c10 /dev/video0 + +Capturing images in YUV formats +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +If we need to output YUV data rather than RGB the color space conversion block +needs to be active, which is achieved by setting MEDIA_BUS_FMT_YUV10_1X30 on the +resizer's source pad. We can then configure a capture format like NV12 (here in +its multi-planar variant) + +.. code-block:: none + + media-ctl -V "'mali-c55 resizer fr':1[fmt:YUV10_1X30/1920x1080]" + yavta -f NV12M -s 1920x1080 -c10 /dev/video0 + +Capturing RGB data from the source and processing it with the resizers +---------------------------------------------------------------------- + +The Mali-C55 ISP can work with sensors capable of outputting RGB data. In this +case although none of the image quality blocks would be used it can still +crop/scale the data in the usual way. For this reason RGB data input to the ISP +still goes through the ISP subdevice's pad 1 to the resizer. + +To achieve this, the ISP's sink pad's format is set to +MEDIA_BUS_FMT_RGB202020_1X60 - this reflects the format that data must be in to +work with the ISP. Converting the camera sensor's output to that format is the +responsibility of external hardware. + +In this example we ask the test pattern generator to give us RGB data instead of +bayer. + +.. code-block:: none + + media-ctl -V "'mali-c55 tpg':0[fmt:RGB202020_1X60/1920x1080]" + media-ctl -V "'mali-c55 isp':0[fmt:RGB202020_1X60/1920x1080]" + +Cropping or scaling the data can be done in exactly the same way as outlined +earlier. + +Capturing raw data from the source and outputting it unmodified +----------------------------------------------------------------- + +The ISP can additionally capture raw data from the source and output it on the +full resolution pipe only, completely unmodified. In this case the downscale +pipe can still process the data normally and be used at the same time. + +To configure raw bypass the FR resizer's subdevice's routing table needs to be +configured, followed by formats in the appropriate places: + +.. code-block:: none + + media-ctl -R "'mali-c55 resizer fr'[0/0->1/0[0],2/0->1/0[1]]" + media-ctl -V "'mali-c55 isp':0[fmt:RGB202020_1X60/1920x1080]" + media-ctl -V "'mali-c55 resizer fr':2[fmt:RGB202020_1X60/1920x1080]" + media-ctl -V "'mali-c55 resizer fr':1[fmt:RGB202020_1X60/1920x1080]" + + # Set format on the video device and stream + yavta -f RGB565 -s 1920x1080 -c10 /dev/video0 + +References +========== +.. [1] https://git.linuxtv.org/v4l-utils.git/ +.. [2] https://git.ideasonboard.org/yavta.git +.. [3] https://developer.arm.com/Processors/Mali-C55 diff --git a/Documentation/admin-guide/media/v4l-drivers.rst b/Documentation/admin-guide/media/v4l-drivers.rst index 4120eded9a13..1d9485860d93 100644 --- a/Documentation/admin-guide/media/v4l-drivers.rst +++ b/Documentation/admin-guide/media/v4l-drivers.rst @@ -18,6 +18,7 @@ Video4Linux (V4L) driver-specific documentation ipu3 ipu6-isys ivtv + mali-c55 mgb4 omap3isp omap4_camera