Re: [PATCH v2 2/9] media: Add Chameleon v3 framebuffer driver

Paweł Anikiel
2024-02-28T15:08:47Z

Hi Hans, thanks for the review!

On Wed, Feb 28, 2024 at 12:24 PM Hans Verkuil <hverkuil-cisco@xs4all.nl> wrote:
>
> Hi Paweł,
>
> On 21/02/2024 17:02, Paweł Anikiel wrote:
> > Add v4l2 driver for the Google Chameleon v3 framebuffer device.
>
> This is just a video capture device, right? A framebuffer device is something
> that lives in drivers/video/fbdev.

Yes, it is just a capture device.

>
> It is *very* confusing to see the term 'framebuffer' used in a video
> capture context.

I agree the name is confusing. I think it started out as something
else and unfortunately stuck around. I think it's possible to change
it, though.

>
> This commit log should also give a better description of the hardware.
> Just a single one-liner is a bit on the short side :-)

Would it be fine to just put the Kconfig help text there?

>
> >
> > Signed-off-by: Paweł Anikiel <panikiel@google.com>
> > ---
> > drivers/media/platform/Kconfig | 1 +
> > drivers/media/platform/Makefile | 1 +
> > drivers/media/platform/google/Kconfig | 3 +
> > drivers/media/platform/google/Makefile | 2 +
> > .../media/platform/google/chameleonv3/Kconfig | 13 +
> > .../platform/google/chameleonv3/Makefile | 3 +
> > .../platform/google/chameleonv3/chv3-fb.c | 895 ++++++++++++++++++
>
> chv3-video.c would be a much better name for chv3-fb.c.
>
> That's a commonly used filename for video capture drivers.

I'm guessing all the instances of fb or framebuffer in the driver
itself should be changed as well in that case?

>
> > 7 files changed, 918 insertions(+)
> > create mode 100644 drivers/media/platform/google/Kconfig
> > create mode 100644 drivers/media/platform/google/Makefile
> > create mode 100644 drivers/media/platform/google/chameleonv3/Kconfig
> > create mode 100644 drivers/media/platform/google/chameleonv3/Makefile
> > create mode 100644 drivers/media/platform/google/chameleonv3/chv3-fb.c
> >
> > diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
> > index 91e54215de3a..b82f7b142b85 100644
> > --- a/drivers/media/platform/Kconfig
> > +++ b/drivers/media/platform/Kconfig
> > @@ -69,6 +69,7 @@ source "drivers/media/platform/aspeed/Kconfig"
> > source "drivers/media/platform/atmel/Kconfig"
> > source "drivers/media/platform/cadence/Kconfig"
> > source "drivers/media/platform/chips-media/Kconfig"
> > +source "drivers/media/platform/google/Kconfig"
> > source "drivers/media/platform/intel/Kconfig"
> > source "drivers/media/platform/marvell/Kconfig"
> > source "drivers/media/platform/mediatek/Kconfig"
> > diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
> > index 3296ec1ebe16..f7067eb05f76 100644
> > --- a/drivers/media/platform/Makefile
> > +++ b/drivers/media/platform/Makefile
> > @@ -12,6 +12,7 @@ obj-y += aspeed/
> > obj-y += atmel/
> > obj-y += cadence/
> > obj-y += chips-media/
> > +obj-y += google/
> > obj-y += intel/
> > obj-y += marvell/
> > obj-y += mediatek/
> > diff --git a/drivers/media/platform/google/Kconfig b/drivers/media/platform/google/Kconfig
> > new file mode 100644
> > index 000000000000..2a5f01034c11
> > --- /dev/null
> > +++ b/drivers/media/platform/google/Kconfig
> > @@ -0,0 +1,3 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +
> > +source "drivers/media/platform/google/chameleonv3/Kconfig"
> > diff --git a/drivers/media/platform/google/Makefile b/drivers/media/platform/google/Makefile
> > new file mode 100644
> > index 000000000000..c971a09faeb4
> > --- /dev/null
> > +++ b/drivers/media/platform/google/Makefile
> > @@ -0,0 +1,2 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +obj-y += chameleonv3/
> > diff --git a/drivers/media/platform/google/chameleonv3/Kconfig b/drivers/media/platform/google/chameleonv3/Kconfig
> > new file mode 100644
> > index 000000000000..76d0383a8589
> > --- /dev/null
> > +++ b/drivers/media/platform/google/chameleonv3/Kconfig
> > @@ -0,0 +1,13 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +
> > +config VIDEO_CHV3_FB
> > + tristate "Google Chameleon v3 framebuffer video driver"
> > + depends on V4L_PLATFORM_DRIVERS
> > + depends on VIDEO_DEV
> > + select VIDEOBUF2_DMA_CONTIG
> > + select V4L2_FWNODE
> > + help
> > + v4l2 driver for the video interface present on the Google
> > + Chameleon v3. The Chameleon v3 uses the framebuffer IP core
> > + to take the video signal from different sources and directly
> > + write frames into memory.
>
> So it is composing different video streams into buffers? Or does it
> capture from a single source at a time? The text is rather ambiguous.

You're right, I'll write a more precise description.

>
> > diff --git a/drivers/media/platform/google/chameleonv3/Makefile b/drivers/media/platform/google/chameleonv3/Makefile
> > new file mode 100644
> > index 000000000000..d63727148688
> > --- /dev/null
> > +++ b/drivers/media/platform/google/chameleonv3/Makefile
> > @@ -0,0 +1,3 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +
> > +obj-$(CONFIG_VIDEO_CHV3_FB) += chv3-fb.o
> > diff --git a/drivers/media/platform/google/chameleonv3/chv3-fb.c b/drivers/media/platform/google/chameleonv3/chv3-fb.c
> > new file mode 100644
> > index 000000000000..35a44365eba0
> > --- /dev/null
> > +++ b/drivers/media/platform/google/chameleonv3/chv3-fb.c
> > @@ -0,0 +1,895 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright 2023-2024 Google LLC.
> > + * Author: Paweł Anikiel <panikiel@google.com>
> > + */
> > +
> > +#include <linux/delay.h>
> > +#include <linux/dma-mapping.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/videodev2.h>
> > +#include <media/v4l2-ctrls.h>
> > +#include <media/v4l2-device.h>
> > +#include <media/v4l2-dv-timings.h>
> > +#include <media/v4l2-event.h>
> > +#include <media/v4l2-fwnode.h>
> > +#include <media/v4l2-ioctl.h>
> > +#include <media/videobuf2-dma-contig.h>
> > +
> > +#define DEVICE_NAME "chv3-fb"
> > +
> > +/*
> > + * The device is expected to report some format even if there's currently no
> > + * active video stream. In such case we default to 1080p.
> > + */
> > +#define DEFAULT_WIDTH 1920
> > +#define DEFAULT_HEIGHT 1080
> > +
> > +#define FB_EN 0x00
> > +#define FB_EN_BIT BIT(0)
> > +#define FB_HEIGHT 0x04
> > +#define FB_WIDTH 0x08
> > +#define FB_BUFFERA 0x0c
> > +#define FB_BUFFERB 0x10
> > +#define FB_BUFFERSIZE 0x14
> > +#define FB_RESET 0x18
> > +#define FB_RESET_BIT BIT(0)
> > +#define FB_ERRORSTATUS 0x1c
> > +#define FB_IOCOLOR 0x20
> > +#define FB_DATARATE 0x24
> > +#define FB_DATARATE_SINGLE 0x0
> > +#define FB_DATARATE_DOUBLE 0x1
> > +#define FB_PIXELMODE 0x28
> > +#define FB_PIXELMODE_SINGLE 0x0
> > +#define FB_PIXELMODE_DOUBLE 0x1
> > +#define FB_SYNCPOLARITY 0x2c
> > +#define FB_DMAFORMAT 0x30
> > +#define FB_DMAFORMAT_8BPC 0x0
> > +#define FB_DMAFORMAT_10BPC_UPPER 0x1
> > +#define FB_DMAFORMAT_10BPC_LOWER 0x2
> > +#define FB_DMAFORMAT_12BPC_UPPER 0x3
> > +#define FB_DMAFORMAT_12BPC_LOWER 0x4
> > +#define FB_DMAFORMAT_16BPC 0x5
> > +#define FB_DMAFORMAT_RAW 0x6
> > +#define FB_DMAFORMAT_8BPC_LEGACY 0x7
> > +#define FB_VERSION 0x34
> > +#define FB_VERSION_CURRENT 0xc0fb0001
> > +
> > +#define FB_IRQ_MASK 0x8
> > +#define FB_IRQ_CLR 0xc
> > +#define FB_IRQ_ALL 0xf
> > +#define FB_IRQ_BUFF0 BIT(0)
> > +#define FB_IRQ_BUFF1 BIT(1)
> > +#define FB_IRQ_RESOLUTION BIT(2)
> > +#define FB_IRQ_ERROR BIT(3)
> > +
> > +struct chv3_fb {
> > + struct device *dev;
> > + void __iomem *iobase;
> > + void __iomem *iobase_irq;
> > +
> > + struct v4l2_device v4l2_dev;
> > + struct vb2_queue queue;
> > + struct video_device vdev;
> > + struct v4l2_pix_format pix_fmt;
> > + struct v4l2_dv_timings timings;
> > +
> > + struct v4l2_async_notifier notifier;
> > + struct v4l2_subdev *subdev;
> > + int subdev_source_pad;
> > +
> > + u32 sequence;
> > + bool writing_to_a;
> > +
> > + struct list_head bufs;
> > + spinlock_t bufs_lock;
> > +
> > + struct mutex fb_lock;
> > +};
> > +
> > +struct chv3_fb_buffer {
> > + struct vb2_v4l2_buffer vb;
> > + struct list_head link;
> > +};
> > +
> > +static void chv3_fb_set_format_resolution(struct chv3_fb *fb, u32 width, u32 height)
> > +{
> > + u32 bytes_per_pixel;
> > +
> > + if (fb->pix_fmt.pixelformat == V4L2_PIX_FMT_RGB24)
> > + bytes_per_pixel = 3;
> > + else
> > + bytes_per_pixel = 4;
> > +
> > + fb->pix_fmt.width = width;
> > + fb->pix_fmt.height = height;
> > + fb->pix_fmt.bytesperline = width * bytes_per_pixel;
> > + fb->pix_fmt.sizeimage = fb->pix_fmt.bytesperline * height;
> > +}
> > +
> > +/*
> > + * The video interface has hardware counters which expose the width and
> > + * height of the current video stream. It can't reliably detect if the stream
> > + * is present or not, so this is only used as a fallback in the case where
> > + * we don't have access to the receiver hardware.
> > + */
> > +static int chv3_fb_query_dv_timings_fallback(struct chv3_fb *fb,
> > + struct v4l2_dv_timings *timings)
> > +{
> > + u32 width, height;
> > +
> > + width = readl(fb->iobase + FB_WIDTH);
> > + height = readl(fb->iobase + FB_HEIGHT);
> > + if (width == 0 || height == 0)
> > + return -ENOLINK;
> > +
> > + memset(timings, 0, sizeof(*timings));
> > + timings->type = V4L2_DV_BT_656_1120;
> > + timings->bt.width = width;
> > + timings->bt.height = height;
> > +
> > + return 0;
> > +}
> > +
> > +static int chv3_fb_query_dv_timings(struct chv3_fb *fb, struct v4l2_dv_timings *timings)
> > +{
> > + if (fb->subdev) {
> > + return v4l2_subdev_call(fb->subdev, pad, query_dv_timings,
> > + fb->subdev_source_pad, timings);
> > + } else {
> > + return chv3_fb_query_dv_timings_fallback(fb, timings);
> > + }
> > +}
> > +
> > +static const struct v4l2_dv_timings_cap chv3_fb_fallback_dv_timings_cap = {
> > + .type = V4L2_DV_BT_656_1120,
> > + .bt = {
> > + .min_width = 0,
>
> This is an unlikely minimum width (ditto for height below).
>
> > + .max_width = 65535,
>
> The max is suspect as well: I would expect it to be a multiple of 2/4/8/16.
>
> > + .min_height = 0,
> > + .max_height = 65535,
> > + .min_pixelclock = 0,
> > + .max_pixelclock = 2147483647,
>
> Ditto for these.

Note: these are used only when there is no controllable endpoint
attached to the video interface, and we don't know what the timing
caps are.

Should I then just pick something like 640x480p24 as min and 8Kp120 as max?

>
> > + .standards = V4L2_DV_BT_STD_CEA861 | V4L2_DV_BT_STD_DMT |
> > + V4L2_DV_BT_STD_CVT | V4L2_DV_BT_STD_GTF,
> > + .capabilities = V4L2_DV_BT_CAP_PROGRESSIVE |
> > + V4L2_DV_BT_CAP_REDUCED_BLANKING |
> > + V4L2_DV_BT_CAP_CUSTOM,
> > + },
> > +};
> > +
> > +static int chv3_fb_enum_dv_timings_fallback(struct chv3_fb *fb,
> > + struct v4l2_enum_dv_timings *timings)
> > +{
> > + return v4l2_enum_dv_timings_cap(timings, &chv3_fb_fallback_dv_timings_cap,
> > + NULL, NULL);
> > +}
> > +
> > +static int chv3_fb_dv_timings_cap_fallback(struct chv3_fb *fb,
> > + struct v4l2_dv_timings_cap *cap)
> > +{
> > + *cap = chv3_fb_fallback_dv_timings_cap;
> > +
> > + return 0;
> > +}
> > +
> > +static void chv3_fb_apply_dv_timings(struct chv3_fb *fb)
> > +{
> > + struct v4l2_dv_timings timings;
> > + int res;
> > +
> > + res = chv3_fb_query_dv_timings(fb, &timings);
> > + if (res)
> > + return;
> > +
> > + fb->timings = timings;
> > + chv3_fb_set_format_resolution(fb, timings.bt.width, timings.bt.height);
> > +}
> > +
> > +static int chv3_fb_querycap(struct file *file, void *fh,
> > + struct v4l2_capability *cap)
> > +{
> > + strscpy(cap->driver, DEVICE_NAME, sizeof(cap->driver));
> > + strscpy(cap->card, "Chameleon v3 video", sizeof(cap->card));
> > +
> > + return 0;
> > +}
> > +
> > +static int chv3_fb_g_fmt_vid_cap(struct file *file, void *fh,
> > + struct v4l2_format *fmt)
> > +{
> > + struct chv3_fb *fb = video_drvdata(file);
> > +
> > + fmt->fmt.pix = fb->pix_fmt;
> > +
> > + return 0;
> > +}
> > +
> > +static int chv3_fb_enum_fmt_vid_cap(struct file *file, void *fh,
> > + struct v4l2_fmtdesc *fmt)
> > +{
> > + struct chv3_fb *fb = video_drvdata(file);
> > +
> > + if (fmt->index != 0)
> > + return -EINVAL;
> > +
> > + fmt->flags = 0;
> > + fmt->pixelformat = fb->pix_fmt.pixelformat;
> > +
> > + return 0;
> > +}
> > +
> > +static int chv3_fb_enum_framesizes(struct file *file, void *fh,
> > + struct v4l2_frmsizeenum *frm)
> > +{
> > + struct chv3_fb *fb = video_drvdata(file);
> > +
> > + if (frm->index != 0)
> > + return -EINVAL;
> > +
> > + if (frm->pixel_format != fb->pix_fmt.pixelformat)
> > + return -EINVAL;
> > +
> > + frm->type = V4L2_FRMSIZE_TYPE_DISCRETE;
> > + frm->discrete.width = fb->pix_fmt.width;
> > + frm->discrete.height = fb->pix_fmt.height;
>
> This is not something you would expect to see supported for a
> video receiver input. This is something you use for camera sensors.
>
> This should almost certainly be dropped.

Thanks for explaining, I'll remove it in v3.

>
> > +
> > + return 0;
> > +}
> > +
> > +static int chv3_fb_g_input(struct file *file, void *fh, unsigned int *index)
> > +{
> > + *index = 0;
> > +
> > + return 0;
> > +}
> > +
> > +static int chv3_fb_s_input(struct file *file, void *fh, unsigned int index)
> > +{
> > + if (index != 0)
> > + return -EINVAL;
> > +
> > + return 0;
> > +}
> > +
> > +static int chv3_fb_enum_input(struct file *file, void *fh,
> > + struct v4l2_input *input)
> > +{
> > + if (input->index != 0)
> > + return -EINVAL;
> > +
> > + strscpy(input->name, "input0", sizeof(input->name));
> > + input->type = V4L2_INPUT_TYPE_CAMERA;
> > + input->capabilities = V4L2_IN_CAP_DV_TIMINGS;
> > +
> > + return 0;
> > +}
> > +
> > +static int chv3_fb_g_edid(struct file *file, void *fh,
> > + struct v4l2_edid *edid)
> > +{
> > + struct chv3_fb *fb = video_drvdata(file);
> > + int res;
> > +
> > + if (!fb->subdev)
> > + return -ENOTTY;
> > +
> > + if (edid->pad != 0)
> > + return -EINVAL;
> > +
> > + edid->pad = fb->subdev_source_pad;
> > + res = v4l2_subdev_call(fb->subdev, pad, get_edid, edid);
> > + edid->pad = 0;
> > +
> > + return res;
> > +}
> > +
> > +static int chv3_fb_s_edid(struct file *file, void *fh,
> > + struct v4l2_edid *edid)
> > +{
> > + struct chv3_fb *fb = video_drvdata(file);
> > + int res;
> > +
> > + if (!fb->subdev)
> > + return -ENOTTY;
> > +
> > + if (edid->pad != 0)
> > + return -EINVAL;
> > +
> > + edid->pad = fb->subdev_source_pad;
> > + res = v4l2_subdev_call(fb->subdev, pad, set_edid, edid);
> > + edid->pad = 0;
> > +
> > + return res;
> > +}
> > +
> > +static int chv3_fb_s_dv_timings(struct file *file, void *fh,
> > + struct v4l2_dv_timings *timings)
> > +{
> > + struct chv3_fb *fb = video_drvdata(file);
> > +
> > + if (timings->bt.width == fb->timings.bt.width &&
> > + timings->bt.height == fb->timings.bt.height)
>
> You would typically use v4l2_match_dv_timings() for this. The check above
> is insufficient since it does not even check for different framerates or
> interlaced vs progressive.

Okay, I changed it to use v4l2_match_dv_timings().

>
> > + return 0;
> > +
> > + if (vb2_is_busy(&fb->queue))
> > + return -EBUSY;
> > +
> > + if (!v4l2_valid_dv_timings(timings, &chv3_fb_fallback_dv_timings_cap, NULL, NULL))
> > + return -ERANGE;
> > +
> > + fb->timings = *timings;
> > + chv3_fb_set_format_resolution(fb, timings->bt.width, timings->bt.height);
> > +
> > + return 0;
> > +}
> > +
> > +static int chv3_fb_g_dv_timings(struct file *file, void *fh,
> > + struct v4l2_dv_timings *timings)
> > +{
> > + struct chv3_fb *fb = video_drvdata(file);
> > +
> > + *timings = fb->timings;
> > + return 0;
> > +}
> > +
> > +static int chv3_fb_vidioc_query_dv_timings(struct file *file, void *fh,
> > + struct v4l2_dv_timings *timings)
> > +{
> > + struct chv3_fb *fb = video_drvdata(file);
> > +
> > + return chv3_fb_query_dv_timings(fb, timings);
> > +}
> > +
> > +static int chv3_fb_enum_dv_timings(struct file *file, void *fh,
> > + struct v4l2_enum_dv_timings *timings)
> > +{
> > + struct chv3_fb *fb = video_drvdata(file);
> > + int res;
> > +
> > + if (timings->pad != 0)
> > + return -EINVAL;
> > +
> > + if (fb->subdev) {
> > + timings->pad = fb->subdev_source_pad;
> > + res = v4l2_subdev_call(fb->subdev, pad, enum_dv_timings, timings);
> > + timings->pad = 0;
> > + return res;
> > + } else {
> > + return chv3_fb_enum_dv_timings_fallback(fb, timings);
> > + }
> > +}
> > +
> > +static int chv3_fb_dv_timings_cap(struct file *file, void *fh,
> > + struct v4l2_dv_timings_cap *cap)
> > +{
> > + struct chv3_fb *fb = video_drvdata(file);
> > + int res;
> > +
> > + if (cap->pad != 0)
> > + return -EINVAL;
> > +
> > + if (fb->subdev) {
> > + cap->pad = fb->subdev_source_pad;
> > + res = v4l2_subdev_call(fb->subdev, pad, dv_timings_cap, cap);
> > + cap->pad = 0;
> > + return res;
> > + } else {
> > + return chv3_fb_dv_timings_cap_fallback(fb, cap);
> > + }
> > +}
> > +
> > +static int chv3_fb_subscribe_event(struct v4l2_fh *fh,
> > + const struct v4l2_event_subscription *sub)
> > +{
> > + switch (sub->type) {
> > + case V4L2_EVENT_SOURCE_CHANGE:
> > + return v4l2_src_change_event_subscribe(fh, sub);
> > + }
> > +
> > + return v4l2_ctrl_subscribe_event(fh, sub);
> > +}
>
> I am missing support for the V4L2_CID_DV_RX_POWER_PRESENT control:
>
> https://hverkuil.home.xs4all.nl/spec/userspace-api/v4l/ext-ctrls-dv.html

I'll try to implement it.

>
> > +
> > +static const struct v4l2_ioctl_ops chv3_fb_v4l2_ioctl_ops = {
> > + .vidioc_querycap = chv3_fb_querycap,
> > +
> > + .vidioc_enum_fmt_vid_cap = chv3_fb_enum_fmt_vid_cap,
> > + .vidioc_g_fmt_vid_cap = chv3_fb_g_fmt_vid_cap,
> > + .vidioc_s_fmt_vid_cap = chv3_fb_g_fmt_vid_cap,
> > + .vidioc_try_fmt_vid_cap = chv3_fb_g_fmt_vid_cap,
> > +
> > + .vidioc_enum_framesizes = chv3_fb_enum_framesizes,
> > +
> > + .vidioc_enum_input = chv3_fb_enum_input,
> > + .vidioc_g_input = chv3_fb_g_input,
> > + .vidioc_s_input = chv3_fb_s_input,
> > + .vidioc_g_edid = chv3_fb_g_edid,
> > + .vidioc_s_edid = chv3_fb_s_edid,
> > +
> > + .vidioc_reqbufs = vb2_ioctl_reqbufs,
> > + .vidioc_create_bufs = vb2_ioctl_create_bufs,
> > + .vidioc_querybuf = vb2_ioctl_querybuf,
> > + .vidioc_prepare_buf = vb2_ioctl_prepare_buf,
> > + .vidioc_expbuf = vb2_ioctl_expbuf,
> > + .vidioc_qbuf = vb2_ioctl_qbuf,
> > + .vidioc_dqbuf = vb2_ioctl_dqbuf,
> > + .vidioc_streamon = vb2_ioctl_streamon,
> > + .vidioc_streamoff = vb2_ioctl_streamoff,
> > +
> > + .vidioc_s_dv_timings = chv3_fb_s_dv_timings,
> > + .vidioc_g_dv_timings = chv3_fb_g_dv_timings,
> > + .vidioc_query_dv_timings = chv3_fb_vidioc_query_dv_timings,
> > + .vidioc_enum_dv_timings = chv3_fb_enum_dv_timings,
> > + .vidioc_dv_timings_cap = chv3_fb_dv_timings_cap,
> > +
> > + .vidioc_subscribe_event = chv3_fb_subscribe_event,
> > + .vidioc_unsubscribe_event = v4l2_event_unsubscribe,
> > +};
> > +
> > +static int chv3_fb_queue_setup(struct vb2_queue *q,
> > + unsigned int *nbuffers, unsigned int *nplanes,
> > + unsigned int sizes[], struct device *alloc_devs[])
> > +{
> > + struct chv3_fb *fb = vb2_get_drv_priv(q);
> > +
> > + if (*nplanes) {
> > + if (sizes[0] < fb->pix_fmt.sizeimage)
> > + return -EINVAL;
> > + return 0;
> > + }
> > + *nplanes = 1;
> > + sizes[0] = fb->pix_fmt.sizeimage;
> > +
> > + return 0;
> > +}
> > +
> > +/*
> > + * There are two address registers: BUFFERA and BUFFERB. The framebuffer
> > + * alternates writing between them (i.e. even frames go to BUFFERA, odd
> > + * ones to BUFFERB).
> > + *
> > + * (buffer queue) > QUEUED ---> QUEUED ---> QUEUED ---> ...
> > + * BUFFERA BUFFERB
> > + * (hw writing to this) ^
> > + * (and then to this) ^
> > + *
> > + * The buffer swapping happens at irq time. When an irq comes, the next
> > + * frame is already assigned an address in the buffer queue. This gives
> > + * the irq handler a whole frame's worth of time to update the buffer
> > + * address register.
> > + */
> > +
> > +static dma_addr_t chv3_fb_buffer_dma_addr(struct chv3_fb_buffer *buf)
> > +{
> > + return vb2_dma_contig_plane_dma_addr(&buf->vb.vb2_buf, 0);
> > +}
> > +
> > +static void chv3_fb_start_frame(struct chv3_fb *fb, struct chv3_fb_buffer *buf)
> > +{
> > + fb->writing_to_a = 1;
> > + writel(chv3_fb_buffer_dma_addr(buf), fb->iobase + FB_BUFFERA);
> > + writel(FB_EN_BIT, fb->iobase + FB_EN);
> > +}
> > +
> > +static void chv3_fb_next_frame(struct chv3_fb *fb, struct chv3_fb_buffer *buf)
> > +{
> > + u32 reg = fb->writing_to_a ? FB_BUFFERB : FB_BUFFERA;
> > +
> > + writel(chv3_fb_buffer_dma_addr(buf), fb->iobase + reg);
> > +}
> > +
> > +static int chv3_fb_start_streaming(struct vb2_queue *q, unsigned int count)
> > +{
> > + struct chv3_fb *fb = vb2_get_drv_priv(q);
> > + struct chv3_fb_buffer *buf;
> > + unsigned long flags;
> > +
> > + fb->sequence = 0;
> > + writel(fb->pix_fmt.sizeimage, fb->iobase + FB_BUFFERSIZE);
> > +
> > + spin_lock_irqsave(&fb->bufs_lock, flags);
> > + buf = list_first_entry_or_null(&fb->bufs, struct chv3_fb_buffer, link);
> > + if (buf) {
> > + chv3_fb_start_frame(fb, buf);
> > + if (!list_is_last(&buf->link, &fb->bufs))
> > + chv3_fb_next_frame(fb, list_next_entry(buf, link));
> > + }
> > + spin_unlock_irqrestore(&fb->bufs_lock, flags);
> > +
> > + return 0;
> > +}
> > +
> > +static void chv3_fb_stop_streaming(struct vb2_queue *q)
> > +{
> > + struct chv3_fb *fb = vb2_get_drv_priv(q);
> > + struct chv3_fb_buffer *buf;
> > + unsigned long flags;
> > +
> > + writel(0, fb->iobase + FB_EN);
> > +
> > + spin_lock_irqsave(&fb->bufs_lock, flags);
> > + list_for_each_entry(buf, &fb->bufs, link)
> > + vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
> > + INIT_LIST_HEAD(&fb->bufs);
> > + spin_unlock_irqrestore(&fb->bufs_lock, flags);
> > +}
> > +
> > +static void chv3_fb_buf_queue(struct vb2_buffer *vb)
> > +{
> > + struct chv3_fb *fb = vb2_get_drv_priv(vb->vb2_queue);
> > + struct vb2_v4l2_buffer *v4l2_buf = to_vb2_v4l2_buffer(vb);
> > + struct chv3_fb_buffer *buf = container_of(v4l2_buf, struct chv3_fb_buffer, vb);
> > + bool first, second;
> > + unsigned long flags;
> > +
> > + spin_lock_irqsave(&fb->bufs_lock, flags);
> > + first = list_empty(&fb->bufs);
> > + second = list_is_singular(&fb->bufs);
> > + list_add_tail(&buf->link, &fb->bufs);
> > + if (vb2_is_streaming(vb->vb2_queue)) {
> > + if (first)
> > + chv3_fb_start_frame(fb, buf);
> > + else if (second)
> > + chv3_fb_next_frame(fb, buf);
> > + }
> > + spin_unlock_irqrestore(&fb->bufs_lock, flags);
> > +}
> > +
> > +static const struct vb2_ops chv3_fb_vb2_ops = {
> > + .queue_setup = chv3_fb_queue_setup,
> > + .wait_prepare = vb2_ops_wait_prepare,
> > + .wait_finish = vb2_ops_wait_finish,
> > + .start_streaming = chv3_fb_start_streaming,
> > + .stop_streaming = chv3_fb_stop_streaming,
> > + .buf_queue = chv3_fb_buf_queue,
> > +};
> > +
> > +static int chv3_fb_open(struct file *file)
> > +{
> > + struct chv3_fb *fb = video_drvdata(file);
> > + int res;
> > +
> > + mutex_lock(&fb->fb_lock);
> > + res = v4l2_fh_open(file);
> > + if (!res) {
> > + if (v4l2_fh_is_singular_file(file))
> > + chv3_fb_apply_dv_timings(fb);
> > + }
> > + mutex_unlock(&fb->fb_lock);
> > +
> > + return res;
> > +}
> > +
> > +static const struct v4l2_file_operations chv3_fb_v4l2_fops = {
> > + .owner = THIS_MODULE,
> > + .open = chv3_fb_open,
> > + .release = vb2_fop_release,
> > + .unlocked_ioctl = video_ioctl2,
> > + .mmap = vb2_fop_mmap,
> > + .poll = vb2_fop_poll,
> > +};
> > +
> > +static void chv3_fb_frame_irq(struct chv3_fb *fb)
> > +{
> > + struct chv3_fb_buffer *buf;
> > +
> > + spin_lock(&fb->bufs_lock);
> > +
> > + buf = list_first_entry_or_null(&fb->bufs, struct chv3_fb_buffer, link);
> > + if (!buf)
> > + goto empty;
> > + list_del(&buf->link);
> > +
> > + vb2_set_plane_payload(&buf->vb.vb2_buf, 0, fb->pix_fmt.sizeimage);
> > + buf->vb.vb2_buf.timestamp = ktime_get_ns();
> > + buf->vb.sequence = fb->sequence++;
> > + buf->vb.field = V4L2_FIELD_NONE;
> > + vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_DONE);
> > +
> > + buf = list_first_entry_or_null(&fb->bufs, struct chv3_fb_buffer, link);
> > + if (buf) {
> > + fb->writing_to_a = !fb->writing_to_a;
> > + if (!list_is_last(&buf->link, &fb->bufs))
> > + chv3_fb_next_frame(fb, list_next_entry(buf, link));
> > + } else {
> > + writel(0, fb->iobase + FB_EN);
> > + }
> > +empty:
> > + spin_unlock(&fb->bufs_lock);
> > +}
> > +
> > +static void chv3_fb_error_irq(struct chv3_fb *fb)
> > +{
> > + if (vb2_is_streaming(&fb->queue))
> > + vb2_queue_error(&fb->queue);
> > +}
> > +
> > +static void chv3_fb_resolution_irq(struct chv3_fb *fb)
> > +{
> > + static const struct v4l2_event event = {
> > + .type = V4L2_EVENT_SOURCE_CHANGE,
> > + .u.src_change.changes = V4L2_EVENT_SRC_CH_RESOLUTION,
> > + };
> > +
> > + v4l2_event_queue(&fb->vdev, &event);
> > + chv3_fb_error_irq(fb);
> > +}
> > +
> > +static irqreturn_t chv3_fb_isr(int irq, void *data)
> > +{
> > + struct chv3_fb *fb = data;
> > + unsigned int reg;
> > +
> > + reg = readl(fb->iobase_irq + FB_IRQ_CLR);
> > + if (!reg)
> > + return IRQ_NONE;
> > +
> > + if (reg & FB_IRQ_BUFF0)
> > + chv3_fb_frame_irq(fb);
> > + if (reg & FB_IRQ_BUFF1)
> > + chv3_fb_frame_irq(fb);
> > + if (reg & FB_IRQ_RESOLUTION)
> > + chv3_fb_resolution_irq(fb);
> > + if (reg & FB_IRQ_ERROR) {
> > + dev_warn(fb->dev, "framebuffer error: 0x%x\n",
> > + readl(fb->iobase + FB_ERRORSTATUS));
> > + chv3_fb_error_irq(fb);
> > + }
> > +
> > + writel(reg, fb->iobase_irq + FB_IRQ_CLR);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static int chv3_fb_check_version(struct chv3_fb *fb)
> > +{
> > + u32 version;
> > +
> > + version = readl(fb->iobase + FB_VERSION);
> > + if (version != FB_VERSION_CURRENT) {
> > + dev_err(fb->dev,
> > + "wrong framebuffer version: expected %x, got %x\n",
> > + FB_VERSION_CURRENT, version);
> > + return -ENODEV;
> > + }
> > + return 0;
> > +}
> > +
> > +static void chv3_fb_set_default_format(struct chv3_fb *fb, bool legacy_format)
> > +{
> > + struct v4l2_pix_format *pix = &fb->pix_fmt;
> > +
> > + if (legacy_format)
> > + pix->pixelformat = V4L2_PIX_FMT_BGRX32;
> > + else
> > + pix->pixelformat = V4L2_PIX_FMT_RGB24;
> > + pix->field = V4L2_FIELD_NONE;
> > + pix->colorspace = V4L2_COLORSPACE_SRGB;
> > +
> > + chv3_fb_set_format_resolution(fb, DEFAULT_WIDTH, DEFAULT_HEIGHT);
> > +}
> > +
> > +static void chv3_fb_set_default_timings(struct chv3_fb *fb)
> > +{
> > + memset(&fb->timings, 0, sizeof(fb->timings));
> > + fb->timings.type = V4L2_DV_BT_656_1120;
> > + fb->timings.bt.width = DEFAULT_WIDTH;
> > + fb->timings.bt.height = DEFAULT_HEIGHT;
>
> Wouldn't it be better to say: fb->timings = V4L2_DV_BT_CEA_1920X1080P60;

Yes, that would work.

>
> > +}
> > +
> > +#define notifier_to_fb(nf) container_of(nf, struct chv3_fb, notifier)
> > +
> > +static int chv3_fb_async_notify_bound(struct v4l2_async_notifier *notifier,
> > + struct v4l2_subdev *subdev,
> > + struct v4l2_async_connection *asc)
> > +{
> > + struct chv3_fb *fb = notifier_to_fb(notifier);
> > + int pad;
> > +
> > + pad = media_entity_get_fwnode_pad(&subdev->entity, asc->match.fwnode,
> > + MEDIA_PAD_FL_SOURCE);
> > + if (pad < 0)
> > + return pad;
> > +
> > + fb->subdev = subdev;
> > + fb->subdev_source_pad = pad;
> > +
> > + return 0;
> > +}
> > +
> > +static void chv3_fb_async_notify_unbind(struct v4l2_async_notifier *notifier,
> > + struct v4l2_subdev *subdev,
> > + struct v4l2_async_connection *asc)
> > +{
> > + struct chv3_fb *fb = notifier_to_fb(notifier);
> > +
> > + video_unregister_device(&fb->vdev);
>
> Use vb2_video_unregister_device. See documentation in include/media/videobuf2-v4l2.h.

So if I understand the docs correctly, I should just change this line to
'vb2_video_unregister_device(&fb->vdev);'?

>
> > +}
> > +
> > +static int chv3_fb_async_notify_complete(struct v4l2_async_notifier *notifier)
> > +{
> > + struct chv3_fb *fb = notifier_to_fb(notifier);
> > +
> > + return video_register_device(&fb->vdev, VFL_TYPE_VIDEO, -1);
> > +}
> > +
> > +static const struct v4l2_async_notifier_operations chv3_fb_async_notify_ops = {
> > + .bound = chv3_fb_async_notify_bound,
> > + .unbind = chv3_fb_async_notify_unbind,
> > + .complete = chv3_fb_async_notify_complete,
> > +};
> > +
> > +static int chv3_fb_fallback_init(struct chv3_fb *fb)
> > +{
> > + fb->subdev = NULL;
> > + fb->subdev_source_pad = 0;
> > +
> > + return video_register_device(&fb->vdev, VFL_TYPE_VIDEO, -1);
> > +}
> > +
> > +static int chv3_fb_fwnode_init(struct chv3_fb *fb)
> > +{
> > + struct v4l2_async_connection *asc;
> > + struct fwnode_handle *endpoint;
> > + int res;
> > +
> > + endpoint = fwnode_graph_get_next_endpoint(dev_fwnode(fb->dev), NULL);
> > + if (!endpoint)
> > + return -EINVAL;
> > +
> > + v4l2_async_nf_init(&fb->notifier, &fb->v4l2_dev);
> > +
> > + asc = v4l2_async_nf_add_fwnode_remote(&fb->notifier, endpoint,
> > + struct v4l2_async_connection);
> > + fwnode_handle_put(endpoint);
> > +
> > + if (IS_ERR(asc))
> > + return PTR_ERR(asc);
> > +
> > + fb->notifier.ops = &chv3_fb_async_notify_ops;
> > + res = v4l2_async_nf_register(&fb->notifier);
> > + if (res) {
> > + v4l2_async_nf_cleanup(&fb->notifier);
> > + return res;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int chv3_fb_probe(struct platform_device *pdev)
> > +{
> > + struct chv3_fb *fb;
> > + bool legacy_format;
> > + int res;
> > + int irq;
> > +
> > + fb = devm_kzalloc(&pdev->dev, sizeof(*fb), GFP_KERNEL);
> > + if (!fb)
> > + return -ENOMEM;
> > + fb->dev = &pdev->dev;
> > + platform_set_drvdata(pdev, fb);
> > +
> > + /* map register space */
> > + fb->iobase = devm_platform_ioremap_resource(pdev, 0);
> > + if (IS_ERR(fb->iobase))
> > + return PTR_ERR(fb->iobase);
> > +
> > + fb->iobase_irq = devm_platform_ioremap_resource(pdev, 1);
> > + if (IS_ERR(fb->iobase_irq))
> > + return PTR_ERR(fb->iobase_irq);
> > +
> > + /* check hw version */
> > + res = chv3_fb_check_version(fb);
> > + if (res)
> > + return res;
> > +
> > + /* setup interrupts */
> > + irq = platform_get_irq(pdev, 0);
> > + if (irq < 0)
> > + return -ENXIO;
> > + res = devm_request_irq(&pdev->dev, irq, chv3_fb_isr, 0, DEVICE_NAME, fb);
> > + if (res)
> > + return res;
> > +
> > + /* initialize v4l2_device */
> > + res = v4l2_device_register(&pdev->dev, &fb->v4l2_dev);
> > + if (res)
> > + return res;
> > +
> > + /* initialize vb2 queue */
> > + fb->queue.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> > + fb->queue.io_modes = VB2_MMAP | VB2_DMABUF;
> > + fb->queue.dev = &pdev->dev;
> > + fb->queue.lock = &fb->fb_lock;
> > + fb->queue.ops = &chv3_fb_vb2_ops;
> > + fb->queue.mem_ops = &vb2_dma_contig_memops;
> > + fb->queue.drv_priv = fb;
> > + fb->queue.buf_struct_size = sizeof(struct chv3_fb_buffer);
> > + fb->queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
> > + res = vb2_queue_init(&fb->queue);
> > + if (res)
> > + goto error;
> > +
> > + /* initialize video_device */
> > + strscpy(fb->vdev.name, DEVICE_NAME, sizeof(fb->vdev.name));
> > + fb->vdev.fops = &chv3_fb_v4l2_fops;
> > + fb->vdev.ioctl_ops = &chv3_fb_v4l2_ioctl_ops;
> > + fb->vdev.lock = &fb->fb_lock;
> > + fb->vdev.release = video_device_release_empty;
> > + fb->vdev.device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING;
> > + fb->vdev.v4l2_dev = &fb->v4l2_dev;
> > + fb->vdev.queue = &fb->queue;
> > + video_set_drvdata(&fb->vdev, fb);
> > +
> > + /* read other DT properties */
> > + legacy_format = device_property_read_bool(&pdev->dev, "google,legacy-format");
> > +
> > + if (device_get_named_child_node(&pdev->dev, "port"))
> > + res = chv3_fb_fwnode_init(fb);
> > + else
> > + res = chv3_fb_fallback_init(fb);
> > + if (res)
> > + goto error;
> > +
> > + /* initialize rest of driver struct */
> > + INIT_LIST_HEAD(&fb->bufs);
> > + spin_lock_init(&fb->bufs_lock);
> > + mutex_init(&fb->fb_lock);
> > +
> > + chv3_fb_set_default_format(fb, legacy_format);
> > + chv3_fb_set_default_timings(fb);
> > +
> > + /* initialize hw */
> > + writel(FB_RESET_BIT, fb->iobase + FB_RESET);
> > + writel(FB_DATARATE_DOUBLE, fb->iobase + FB_DATARATE);
> > + writel(FB_PIXELMODE_DOUBLE, fb->iobase + FB_PIXELMODE);
> > + if (legacy_format)
> > + writel(FB_DMAFORMAT_8BPC_LEGACY, fb->iobase + FB_DMAFORMAT);
> > + else
> > + writel(FB_DMAFORMAT_8BPC, fb->iobase + FB_DMAFORMAT);
> > +
> > + writel(FB_IRQ_ALL, fb->iobase_irq + FB_IRQ_MASK);
> > +
> > + return 0;
> > +
> > +error:
> > + v4l2_device_unregister(&fb->v4l2_dev);
> > +
> > + return res;
> > +}
> > +
> > +static void chv3_fb_remove(struct platform_device *pdev)
> > +{
> > + struct chv3_fb *fb = platform_get_drvdata(pdev);
> > +
> > + /* disable interrupts */
> > + writel(0, fb->iobase_irq + FB_IRQ_MASK);
> > +
> > + v4l2_async_nf_unregister(&fb->notifier);
> > + v4l2_async_nf_cleanup(&fb->notifier);
> > + v4l2_device_unregister(&fb->v4l2_dev);
> > +}
> > +
> > +static const struct of_device_id chv3_fb_match_table[] = {
> > + { .compatible = "google,chv3-fb" },
> > + { },
> > +};
> > +
> > +static struct platform_driver chv3_fb_platform_driver = {
> > + .probe = chv3_fb_probe,
> > + .remove_new = chv3_fb_remove,
> > + .driver = {
> > + .name = DEVICE_NAME,
> > + .of_match_table = chv3_fb_match_table,
> > + },
> > +};
> > +
> > +module_platform_driver(chv3_fb_platform_driver);
> > +
> > +MODULE_AUTHOR("Paweł Anikiel <panikiel@google.com>");
> > +MODULE_DESCRIPTION("Google Chameleon v3 video framebuffer driver");
> > +MODULE_LICENSE("GPL");
>
> For the v3, can you also provide the output of 'v4l2-compliance -s'
> in the cover letter? Make sure you compile v4l2-compliance directly
> from the git repo https://git.linuxtv.org/v4l-utils.git/ since the version
> from distros is usually too old.

Okay, I'll do that.