Re: [RFC PATCH v1 4/5] media: tegra: Add Tegra Video input driver for Tegra210

From: Sowjanya Komatineni
Date: Tue Jan 28 2020 - 19:49:10 EST



On 1/28/20 2:13 PM, Sowjanya Komatineni wrote:

On 1/28/20 1:45 PM, Helen Koike wrote:
External email: Use caution opening links or attachments


Hi Sowjanya,

I just took a really quick look, I didn't check the driver in deep, so just some small comments below.

On 1/28/20 4:23 PM, Sowjanya Komatineni wrote:
Tegra210 contains a powerful Video Input (VI) hardware controller
which can support up to 6 MIPI CSI camera sensors.

Each Tegra CSI port can be one-to-one mapped to VI channel and can
capture from an external camera sensor connected to CSI or from
built-in test pattern generator.

Tegra210 supports built-in test pattern generator from CSI to VI.

This patch adds a V4L2 media controller and capture driver support
for Tegra210 built-in CSI to VI test pattern generator.

Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
Could you send us the output of media-ctl --print-dot ? So we can view the media topology easily?
root@tegra-ubuntu:/home/ubuntu# ./media-ctl --print-dot
digraph board {
ÂÂÂÂÂÂÂ rankdir=TB
ÂÂÂÂÂÂÂ n00000001 [label="54080000.vi-output-0\n/dev/video0", shape=box, style=filled, fillcolor=yellow]
ÂÂÂÂÂÂÂ n00000005 [label="54080000.vi-output-1\n/dev/video1", shape=box, style=filled, fillcolor=yellow]
ÂÂÂÂÂÂÂ n00000009 [label="54080000.vi-output-2\n/dev/video2", shape=box, style=filled, fillcolor=yellow]
ÂÂÂÂÂÂÂ n0000000d [label="54080000.vi-output-3\n/dev/video3", shape=box, style=filled, fillcolor=yellow]
ÂÂÂÂÂÂÂ n00000011 [label="54080000.vi-output-4\n/dev/video4", shape=box, style=filled, fillcolor=yellow]
ÂÂÂÂÂÂÂ n00000015 [label="54080000.vi-output-5\n/dev/video5", shape=box, style=filled, fillcolor=yellow]
ÂÂÂÂÂÂÂ n00000019 [label="{{} | tpg-0 | {<port0> 0}}", shape=Mrecord, style=filled, fillcolor=green]
ÂÂÂÂÂÂÂ n00000019:port0 -> n00000001
ÂÂÂÂÂÂÂ n0000001d [label="{{} | tpg-1 | {<port0> 0}}", shape=Mrecord, style=filled, fillcolor=green]
ÂÂÂÂÂÂÂ n0000001d:port0 -> n00000005
ÂÂÂÂÂÂÂ n00000021 [label="{{} | tpg-2 | {<port0> 0}}", shape=Mrecord, style=filled, fillcolor=green]
ÂÂÂÂÂÂÂ n00000021:port0 -> n00000009
ÂÂÂÂÂÂÂ n00000025 [label="{{} | tpg-3 | {<port0> 0}}", shape=Mrecord, style=filled, fillcolor=green]
ÂÂÂÂÂÂÂ n00000025:port0 -> n0000000d
ÂÂÂÂÂÂÂ n00000029 [label="{{} | tpg-4 | {<port0> 0}}", shape=Mrecord, style=filled, fillcolor=green]
ÂÂÂÂÂÂÂ n00000029:port0 -> n00000011
ÂÂÂÂÂÂÂ n0000002d [label="{{} | tpg-5 | {<port0> 0}}", shape=Mrecord, style=filled, fillcolor=green]
ÂÂÂÂÂÂÂ n0000002d:port0 -> n00000015
}


--- diff --git a/drivers/staging/media/tegra/host1x-video.h b/drivers/staging/media/tegra/host1x-video.h
new file mode 100644
index 000000000000..84d28e6f4362
--- /dev/null
+++ b/drivers/staging/media/tegra/host1x-video.h
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 NVIDIA CORPORATION. All rights reserved.
+ */
+
+#ifndef HOST1X_VIDEO_H
+#define HOST1X_VIDEO_H 1
+
+#include <linux/host1x.h>
+
+#include <media/media-device.h>
+#include <media/media-entity.h>
+#include <media/v4l2-async.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-dev.h>
+#include <media/videobuf2-v4l2.h>
+
+#include "tegra-vi.h"
+#include "csi.h"
+
+struct tegra_camera {
+ÂÂÂÂ struct v4l2_device v4l2_dev;
+ÂÂÂÂ struct media_device media_dev;
+ÂÂÂÂ struct device *dev;
You can use cam->media_dev.dev instead of having this pointer.

Will fix in v2
+ÂÂÂÂ struct tegra_vi *vi;
+ÂÂÂÂ struct tegra_csi_device *csi;
+};
+
+
+#define to_tegra_channel(vdev) \
+ÂÂÂÂ container_of(vdev, struct tegra_channel, video)
Why not inline instead of define. Inlines has the advantage of checking types.
Will change in v2

+static int __tegra_channel_try_format(struct tegra_channel *chan,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct v4l2_pix_format *pix,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ const struct tegra_video_format **vfmt)
+{
+ÂÂÂÂ const struct tegra_video_format *fmt_info;
+ÂÂÂÂ struct v4l2_subdev *subdev;
+ÂÂÂÂ struct v4l2_subdev_format fmt;
+ÂÂÂÂ struct v4l2_subdev_pad_config *pad_cfg;
+
+ÂÂÂÂ subdev = tegra_channel_get_remote_subdev(chan);
+ÂÂÂÂ pad_cfg = v4l2_subdev_alloc_pad_config(subdev);
+ÂÂÂÂ if (!pad_cfg)
+ÂÂÂÂÂÂÂÂÂÂÂÂ return -ENOMEM;
+
+ÂÂÂÂ /*
+ÂÂÂÂÂ * Retrieve format information and select the default format if the
+ÂÂÂÂÂ * requested format isn't supported.
+ÂÂÂÂÂ */
+ÂÂÂÂ fmt_info = tegra_core_get_format_by_fourcc(chan, pix->pixelformat);
+ÂÂÂÂ if (!fmt_info) {
+ÂÂÂÂÂÂÂÂÂÂÂÂ pix->pixelformat = chan->format.pixelformat;
+ÂÂÂÂÂÂÂÂÂÂÂÂ pix->colorspace = chan->format.colorspace;
+ÂÂÂÂÂÂÂÂÂÂÂÂ fmt_info = tegra_core_get_format_by_fourcc(chan,
+ pix->pixelformat);
+ÂÂÂÂ }
+
+ÂÂÂÂ /* Change this when start adding interlace format support */
+ÂÂÂÂ pix->field = V4L2_FIELD_NONE;
+ÂÂÂÂ fmt.which = V4L2_SUBDEV_FORMAT_TRY;
+ÂÂÂÂ fmt.pad = 0;
+ÂÂÂÂ v4l2_fill_mbus_format(&fmt.format, pix, fmt_info->code);
+ÂÂÂÂ v4l2_subdev_call(subdev, pad, set_fmt, pad_cfg, &fmt);
As fas as I understand, entities formats should be independent, it is up to link_validate
to check formats between entities.
The capture shouldn't change the format of the subdevice.

Tegra Built-in TPG on CSI accepts specific TPG sizes and CSI is source and VI is sink.

link validation happens only for sink ends of the link.

So with CSI subdev set_fmt sets width/height to default incase if width/height is not from one of the supported sizes.


+
+ÂÂÂÂ v4l2_fill_pix_format(pix, &fmt.format);
+ÂÂÂÂ tegra_channel_fmt_align(chan, &fmt_info->bpp, &pix->width, &pix->height,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ &pix->bytesperline);
+ÂÂÂÂ pix->sizeimage = pix->bytesperline * pix->height;
+
+ÂÂÂÂ if (vfmt)
+ÂÂÂÂÂÂÂÂÂÂÂÂ *vfmt = fmt_info;
+
+ÂÂÂÂ v4l2_subdev_free_pad_config(pad_cfg);
+
+ÂÂÂÂ return 0;
+}
+
+static int tegra_channel_try_format(struct file *file, void *fh,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct v4l2_format *format)
+{
+ÂÂÂÂ struct v4l2_fh *vfh = file->private_data;
+ÂÂÂÂ struct tegra_channel *chan = to_tegra_channel(vfh->vdev);
+
+ÂÂÂÂ return __tegra_channel_try_format(chan, &format->fmt.pix, NULL);
+}
+
+static int tegra_channel_set_format(struct file *file, void *fh,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct v4l2_format *format)
+{
+ÂÂÂÂ struct v4l2_fh *vfh = file->private_data;
+ÂÂÂÂ struct tegra_channel *chan = to_tegra_channel(vfh->vdev);
+ÂÂÂÂ const struct tegra_video_format *info;
+ÂÂÂÂ int ret;
+ÂÂÂÂ struct v4l2_subdev_format fmt;
+ÂÂÂÂ struct v4l2_subdev *subdev;
+ÂÂÂÂ struct v4l2_pix_format *pix = &format->fmt.pix;
+
+ÂÂÂÂ if (vb2_is_busy(&chan->queue))
+ÂÂÂÂÂÂÂÂÂÂÂÂ return -EBUSY;
+
+ÂÂÂÂ /* get supported format by try_fmt */
+ÂÂÂÂ ret = __tegra_channel_try_format(chan, pix, &info);
+ÂÂÂÂ if (ret)
+ÂÂÂÂÂÂÂÂÂÂÂÂ return ret;
+
+ÂÂÂÂ subdev = tegra_channel_get_remote_subdev(chan);
+
+ÂÂÂÂ fmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
+ÂÂÂÂ fmt.pad = 0;
+ÂÂÂÂ v4l2_fill_mbus_format(&fmt.format, pix, info->code);
+ÂÂÂÂ v4l2_subdev_call(subdev, pad, set_fmt, NULL, &fmt);
same here.

Calling subdev set_fmt here for the same reason as explained above.
+
+ÂÂÂÂ v4l2_fill_pix_format(pix, &fmt.format);
+ÂÂÂÂ chan->format = *pix;
+ÂÂÂÂ chan->fmtinfo = info;
+ÂÂÂÂ tegra_channel_update_format(chan, pix->width,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ pix->height, info->fourcc,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ &info->bpp,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ pix->bytesperline);
+ÂÂÂÂ *pix = chan->format;
+
+ÂÂÂÂ return 0;
+}
+
+static int tegra_channel_enum_input(struct file *file, void *fh,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct v4l2_input *inp)
+{
+ÂÂÂÂ /* Currently driver supports internal TPG only */
+ÂÂÂÂ if (inp->index != 0)
just
if (inp->index)

Will update in v2
+ÂÂÂÂÂÂÂÂÂÂÂÂ return -EINVAL;
+
+ÂÂÂÂ inp->type = V4L2_INPUT_TYPE_CAMERA;
+ÂÂÂÂ strscpy(inp->name, "Tegra TPG", sizeof(inp->name));
+
+ÂÂÂÂ return 0;
+}
+static const struct tegra_video_format tegra_default_format = {
+ÂÂÂÂ /* RAW 10 */
+ÂÂÂÂ TEGRA_VF_RAW10,
+ÂÂÂÂ 10,
+ÂÂÂÂ MEDIA_BUS_FMT_SRGGB10_1X10,
+ÂÂÂÂ {2, 1},
+ÂÂÂÂ TEGRA_IMAGE_FORMAT_DEF,
+ÂÂÂÂ TEGRA_IMAGE_DT_RAW10,
+ÂÂÂÂ V4L2_PIX_FMT_SRGGB10,
+ÂÂÂÂ "RGRG.. GBGB..",
It would be more readable to do:

.code = TEGRA_VF_RAW10,
.width = 10,
.code = MEDIA_BUS_FMT_SRGGB10_1X10,

and so on
Will update in v2

+};
+
+/*
+ * Helper functions
+ */
+
+/**
+ * tegra_core_get_default_format - Get default format
+ *
+ * Return: pointer to the format where the default format needs
+ * to be filled in.
+ */
+const struct tegra_video_format *tegra_core_get_default_format(void)
+{
+ÂÂÂÂ return &tegra_default_format;
+}
This is only used in tegra-channel.c, why not to declare it there as static?

Will move all video format retrieval helper functions to corresponding file as static in v2
+ +static struct v4l2_frmsize_discrete tegra_csi_tpg_sizes[] = {
+ÂÂÂÂ {1280, 720},
+ÂÂÂÂ {1920, 1080},
+ÂÂÂÂ {3840, 2160},
+};
+
+/*
+ * V4L2 Subdevice Pad Operations
+ */
+static int tegra_csi_get_format(struct v4l2_subdev *subdev,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct v4l2_subdev_pad_config *cfg,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct v4l2_subdev_format *fmt)
+{
+ÂÂÂÂ struct tegra_csi_channel *csi_chan = to_csi_chan(subdev);
+
+ÂÂÂÂ mutex_lock(&csi_chan->format_lock);
Do you need this lock? I think there is already a serialization in the ioctls in place (to be confirmed).

This is on CSI v4l2 subdevice side during format updates
+ÂÂÂÂ memcpy(fmt, &csi_chan->ports->format,
+ÂÂÂÂÂÂÂÂÂÂÂ sizeof(struct v4l2_mbus_framefmt));
I would prefer just:
*fmt = *csi_chan->ports->format;

I think it is easier to read IMHO.
same in tegra_csi_set_format().

Will fix in v2
+ mutex_unlock(&csi_chan->format_lock);
+
+ÂÂÂÂ return 0;
+}
+
+static void tegra_csi_try_mbus_fmt(struct v4l2_subdev *subdev,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct v4l2_mbus_framefmt *mfmt)
+{
+ÂÂÂÂ struct tegra_csi_channel *csi_chan = to_csi_chan(subdev);
+ÂÂÂÂ struct tegra_csi_device *csi = csi_chan->csi;
+ÂÂÂÂ const struct v4l2_frmsize_discrete *sizes;
+ÂÂÂÂ int i, j;
unsigned

Will fix in v2
+
+ÂÂÂÂ for (i = 0; i < ARRAY_SIZE(tegra_csi_tpg_fmts); i++) {
+ÂÂÂÂÂÂÂÂÂÂÂÂ struct v4l2_mbus_framefmt *mbus_fmt = &tegra_csi_tpg_fmts[i];
+
+ÂÂÂÂÂÂÂÂÂÂÂÂ if (mfmt->code == mbus_fmt->code) {
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ for (j = 0; j < ARRAY_SIZE(tegra_csi_tpg_sizes); j++) {
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ sizes = &tegra_csi_tpg_sizes[j];
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ if (mfmt->width == sizes->width &&
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ mfmt->height == sizes->height) {
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ return;
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ }
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ }
+ÂÂÂÂÂÂÂÂÂÂÂÂ }
+
+ÂÂÂÂÂÂÂÂÂÂÂÂ dev_info(csi->dev, "using Tegra default RAW10 video format\n");
+ÂÂÂÂ }
+
+ÂÂÂÂ dev_info(csi->dev, "using Tegra default WIDTH X HEIGHT (1920x1080)\n");
+ÂÂÂÂ memcpy(mfmt, tegra_csi_tpg_fmts, sizeof(struct v4l2_mbus_framefmt));
+}
+
+