Message-ID: <108e2c3c-243f-cd67-2df7-57541b28ca39@xs4all.nl>
Date:   Tue, 12 Dec 2017 16:47:51 +0100
From:   Hans Verkuil <hverkuil@...all.nl>
To:     Jose Abreu <Jose.Abreu@...opsys.com>, linux-media@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Joao Pinto <Joao.Pinto@...opsys.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Hans Verkuil <hans.verkuil@...co.com>,
        Sylwester Nawrocki <snawrocki@...nel.org>,
        Sakari Ailus <sakari.ailus@....fi>,
        Philippe Ombredanne <pombredanne@...b.com>
Subject: Re: [PATCH v10 4/4] [media] platform: Add Synopsys DesignWare HDMI RX
 Controller Driver

Hi Jose,

Some more comments:

On 11/12/17 18:41, Jose Abreu wrote:
> This is an initial submission for the Synopsys DesignWare HDMI RX
> Controller Driver. This driver interacts with a phy driver so that
> a communication between them is created and a video pipeline is
> configured.
> 
> The controller + phy pipeline can then be integrated into a fully
> featured system that can be able to receive video up to 4k@...z
> with deep color 48bit RGB, depending on the platform. Although,
> this initial version does not yet handle deep color modes.
> 
> This driver was implemented as a standard V4L2 subdevice and its
> main features are:
> 	- Internal state machine that reconfigures phy until the
> 	video is not stable
> 	- JTAG communication with phy
> 	- Inter-module communication with phy driver
> 	- Debug write/read ioctls
> 
> Some notes:
> 	- RX sense controller (cable connection/disconnection) must
> 	be handled by the platform wrapper as this is not integrated
> 	into the controller RTL
> 	- The same goes for EDID ROM's
> 	- ZCAL calibration is needed only in FPGA platforms, in ASIC
> 	this is not needed
> 	- The state machine is not an ideal solution as it creates a
> 	kthread but it is needed because some sources might not be
> 	very stable at sending the video (i.e. we must react
> 	accordingly).
> 
> Signed-off-by: Jose Abreu <joabreu@...opsys.com>
> Cc: Joao Pinto <jpinto@...opsys.com>
> Cc: Mauro Carvalho Chehab <mchehab@...nel.org>
> Cc: Hans Verkuil <hans.verkuil@...co.com>
> Cc: Sylwester Nawrocki <snawrocki@...nel.org>
> Cc: Sakari Ailus <sakari.ailus@....fi>
> Cc: Philippe Ombredanne <pombredanne@...b.com>
> ---
> Changes from v9:
> 	- Use SPDX License ID (Philippe)
> 	- Use LOW_DRIVE CEC error (Hans)
> 	- Fill bt->il_* fields (Hans)
> 	- Fix format->field to NONE (Hans)
> 	- Drop a left-over comment (Hans)
> 	- Use CEC_CAP_DEFAULTS (Hans)
> Changes from v8:
> 	- Incorporate Sakari's work on ASYNC subdevs
> Changes from v6:
> 	- edid-phandle now also looks for parent node (Sylwester)
> 	- Fix kbuild build warnings
> Changes from v5:
> 	- Removed HDCP 1.4 support (Hans)
> 	- Removed some CEC debug messages (Hans)
> 	- Add s_dv_timings callback (Hans)
> 	- Add V4L2_CID_DV_RX_POWER_PRESENT ctrl (Hans)
> Changes from v4:
> 	- Add flag V4L2_SUBDEV_FL_HAS_DEVNODE (Sylwester)
> 	- Remove some comments and change some messages to dev_dbg (Sylwester)
> 	- Use v4l2_async_subnotifier_register() (Sylwester)
> Changes from v3:
> 	- Use v4l2 async API (Sylwester)
> 	- Do not block waiting for phy
> 	- Do not use busy waiting delays (Sylwester)
> 	- Simplify dw_hdmi_power_on (Sylwester)
> 	- Use clock API (Sylwester)
> 	- Use compatible string (Sylwester)
> 	- Minor fixes (Sylwester)
> Changes from v2:
> 	- Address review comments from Hans regarding CEC
> 	- Use CEC notifier
> 	- Enable SCDC
> Changes from v1:
> 	- Add support for CEC
> 	- Correct typo errors
> 	- Correctly detect interlaced video modes
> 	- Correct VIC parsing
> Changes from RFC:
> 	- Add support for HDCP 1.4
> 	- Fixup HDMI_VIC not being parsed (Hans)
> 	- Send source change signal when powering off (Hans)
> 	- Add a "wait stable delay"
> 	- Detect interlaced video modes (Hans)
> 	- Restrain g/s_register from reading/writing to HDCP regs (Hans)
> ---
>  drivers/media/platform/dwc/Kconfig      |   15 +
>  drivers/media/platform/dwc/Makefile     |    1 +
>  drivers/media/platform/dwc/dw-hdmi-rx.c | 1840 +++++++++++++++++++++++++++++++
>  drivers/media/platform/dwc/dw-hdmi-rx.h |  419 +++++++
>  include/media/dwc/dw-hdmi-rx-pdata.h    |   48 +
>  5 files changed, 2323 insertions(+)
>  create mode 100644 drivers/media/platform/dwc/dw-hdmi-rx.c
>  create mode 100644 drivers/media/platform/dwc/dw-hdmi-rx.h
>  create mode 100644 include/media/dwc/dw-hdmi-rx-pdata.h
> 
> diff --git a/drivers/media/platform/dwc/Kconfig b/drivers/media/platform/dwc/Kconfig
> index 361d38d..3ddccde 100644
> --- a/drivers/media/platform/dwc/Kconfig
> +++ b/drivers/media/platform/dwc/Kconfig
> @@ -6,3 +6,18 @@ config VIDEO_DWC_HDMI_PHY_E405
>  
>  	  To compile this driver as a module, choose M here. The module
>  	  will be called dw-hdmi-phy-e405.
> +
> +config VIDEO_DWC_HDMI_RX
> +	tristate "Synopsys Designware HDMI Receiver driver"
> +	depends on VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API
> +	help
> +	  Support for Synopsys Designware HDMI RX controller.
> +
> +	  To compile this driver as a module, choose M here. The module
> +	  will be called dw-hdmi-rx.
> +
> +config VIDEO_DWC_HDMI_RX_CEC
> +	bool
> +	depends on VIDEO_DWC_HDMI_RX
> +	select CEC_CORE
> +	select CEC_NOTIFIER
> diff --git a/drivers/media/platform/dwc/Makefile b/drivers/media/platform/dwc/Makefile
> index fc3b62c..cd04ca9 100644
> --- a/drivers/media/platform/dwc/Makefile
> +++ b/drivers/media/platform/dwc/Makefile
> @@ -1 +1,2 @@
>  obj-$(CONFIG_VIDEO_DWC_HDMI_PHY_E405) += dw-hdmi-phy-e405.o
> +obj-$(CONFIG_VIDEO_DWC_HDMI_RX) += dw-hdmi-rx.o
> diff --git a/drivers/media/platform/dwc/dw-hdmi-rx.c b/drivers/media/platform/dwc/dw-hdmi-rx.c
> new file mode 100644
> index 0000000..437351e
> --- /dev/null
> +++ b/drivers/media/platform/dwc/dw-hdmi-rx.c

<snip>

> +static int dw_hdmi_s_routing(struct v4l2_subdev *sd, u32 input, u32 output,
> +		u32 config)
> +{
> +	struct dw_hdmi_dev *dw_dev = to_dw_dev(sd);
> +
> +	if (!has_signal(dw_dev, input))
> +		return -EINVAL;

Why would this be a reason to reject this? There may be no signal now, but a signal
might appear later.

> +
> +	dw_dev->selected_input = input;
> +	if (input == dw_dev->configured_input)
> +		return 0;
> +
> +	dw_hdmi_power_off(dw_dev);
> +	return dw_hdmi_power_on(dw_dev, input);
> +}
> +
> +static int dw_hdmi_g_input_status(struct v4l2_subdev *sd, u32 *status)
> +{
> +	struct dw_hdmi_dev *dw_dev = to_dw_dev(sd);
> +
> +	*status = 0;
> +	if (!has_signal(dw_dev, dw_dev->selected_input))
> +		*status |= V4L2_IN_ST_NO_POWER;
> +	if (is_off(dw_dev))
> +		*status |= V4L2_IN_ST_NO_SIGNAL;
> +
> +	dev_dbg(dw_dev->dev, "%s: status=0x%x\n", __func__, *status);
> +	return 0;
> +}
> +
> +static int dw_hdmi_g_parm(struct v4l2_subdev *sd, struct v4l2_streamparm *parm)
> +{
> +	struct dw_hdmi_dev *dw_dev = to_dw_dev(sd);
> +
> +	dev_dbg(dw_dev->dev, "%s\n", __func__);
> +
> +	/* TODO: Use helper to compute timeperframe */
> +	parm->parm.capture.timeperframe.numerator = 1;
> +	parm->parm.capture.timeperframe.denominator = 60;
> +	return 0;
> +}
> +
> +static int dw_hdmi_s_dv_timings(struct v4l2_subdev *sd,
> +		struct v4l2_dv_timings *timings)
> +{
> +	struct dw_hdmi_dev *dw_dev = to_dw_dev(sd);
> +
> +	dev_dbg(dw_dev->dev, "%s\n", __func__);
> +	if (!v4l2_valid_dv_timings(timings, &dw_hdmi_timings_cap, NULL, NULL))
> +		return -EINVAL;
> +	if (v4l2_match_dv_timings(timings, &dw_dev->timings, 0, false))
> +		return 0;
> +
> +	dw_dev->timings = *timings;
> +	return 0;
> +}
> +
> +static int dw_hdmi_g_dv_timings(struct v4l2_subdev *sd,
> +		struct v4l2_dv_timings *timings)
> +{
> +	struct dw_hdmi_dev *dw_dev = to_dw_dev(sd);
> +
> +	dev_dbg(dw_dev->dev, "%s\n", __func__);
> +
> +	*timings = dw_dev->timings;
> +	return 0;
> +}
> +
> +static int dw_hdmi_query_dv_timings(struct v4l2_subdev *sd,
> +		struct v4l2_dv_timings *timings)
> +{
> +	struct dw_hdmi_dev *dw_dev = to_dw_dev(sd);
> +	struct v4l2_bt_timings *bt = &timings->bt;
> +	bool is_hdmi_vic;
> +	u32 htot, hofs;
> +	u32 vtot;
> +	u8 vic;
> +
> +	dev_dbg(dw_dev->dev, "%s\n", __func__);
> +
> +	memset(timings, 0, sizeof(*timings));
> +
> +	timings->type = V4L2_DV_BT_656_1120;
> +	bt->width = hdmi_readl(dw_dev, HDMI_MD_HACT_PX);
> +	bt->height = hdmi_readl(dw_dev, HDMI_MD_VAL);
> +	bt->interlaced = hdmi_readl(dw_dev, HDMI_MD_STS) & HDMI_MD_STS_ILACE ?
> +		V4L2_DV_INTERLACED : V4L2_DV_PROGRESSIVE;
> +
> +	if (hdmi_readl(dw_dev, HDMI_ISTS) & HDMI_ISTS_VS_POL_ADJ)
> +		bt->polarities |= V4L2_DV_VSYNC_POS_POL;
> +	if (hdmi_readl(dw_dev, HDMI_ISTS) & HDMI_ISTS_HS_POL_ADJ)
> +		bt->polarities |= V4L2_DV_HSYNC_POS_POL;
> +
> +	bt->pixelclock = dw_hdmi_get_pixelclk(dw_dev);
> +
> +	/* HTOT = HACT + HFRONT + HSYNC + HBACK */
> +	htot = hdmi_mask_readl(dw_dev, HDMI_MD_HT1,
> +			HDMI_MD_HT1_HTOT_PIX_OFFSET,
> +			HDMI_MD_HT1_HTOT_PIX_MASK);
> +	/* HOFS = HSYNC + HBACK */
> +	hofs = hdmi_mask_readl(dw_dev, HDMI_MD_HT1,
> +			HDMI_MD_HT1_HOFS_PIX_OFFSET,
> +			HDMI_MD_HT1_HOFS_PIX_MASK);
> +
> +	bt->hfrontporch = htot - hofs - bt->width;
> +	bt->hsync = hdmi_mask_readl(dw_dev, HDMI_MD_HT0,
> +			HDMI_MD_HT0_HS_CLK_OFFSET,
> +			HDMI_MD_HT0_HS_CLK_MASK);
> +	bt->hbackporch = hofs - bt->hsync;
> +
> +	/* VTOT = VACT + VFRONT + VSYNC + VBACK */
> +	vtot = hdmi_readl(dw_dev, HDMI_MD_VTL);
> +
> +	hdmi_mask_writel(dw_dev, 0x1, HDMI_MD_VCTRL,
> +			HDMI_MD_VCTRL_V_OFFS_LIN_MODE_OFFSET,
> +			HDMI_MD_VCTRL_V_OFFS_LIN_MODE_MASK);
> +	msleep(50); /* Wait for 1 field */

How do you know this waits for 1 field? Or is this: "Wait for at least 1 field"?
I don't know exactly how the IP does this, but it looks fishy to me. If it is
correct, then it could use a few comments about what is going on here as it is
not obvious.

And what happens if the framerate is even slower? You know the pixelclock and
total width+height, so you can calculate the framerate from that.

> +	bt->vsync = hdmi_readl(dw_dev, HDMI_MD_VOL);
> +
> +	hdmi_mask_writel(dw_dev, 0x0, HDMI_MD_VCTRL,
> +			HDMI_MD_VCTRL_V_OFFS_LIN_MODE_OFFSET,
> +			HDMI_MD_VCTRL_V_OFFS_LIN_MODE_MASK);
> +	msleep(50); /* Wait for 1 field */
> +	bt->vbackporch = hdmi_readl(dw_dev, HDMI_MD_VOL);
> +	bt->vfrontporch = vtot - bt->height - bt->vsync - bt->vbackporch;
> +
> +	if (bt->interlaced == V4L2_DV_INTERLACED) {
> +		hdmi_mask_writel(dw_dev, 0x1, HDMI_MD_VCTRL,
> +				HDMI_MD_VCTRL_V_MODE_OFFSET,
> +				HDMI_MD_VCTRL_V_MODE_MASK);
> +		msleep(100); /* Wait for 2 fields */
> +
> +		vtot = hdmi_readl(dw_dev, HDMI_MD_VTL);
> +		hdmi_mask_writel(dw_dev, 0x1, HDMI_MD_VCTRL,
> +				HDMI_MD_VCTRL_V_OFFS_LIN_MODE_OFFSET,
> +				HDMI_MD_VCTRL_V_OFFS_LIN_MODE_MASK);
> +		msleep(50); /* Wait for 1 field */
> +		bt->il_vsync = hdmi_readl(dw_dev, HDMI_MD_VOL);
> +
> +		hdmi_mask_writel(dw_dev, 0x0, HDMI_MD_VCTRL,
> +				HDMI_MD_VCTRL_V_OFFS_LIN_MODE_OFFSET,
> +				HDMI_MD_VCTRL_V_OFFS_LIN_MODE_MASK);
> +		msleep(50);
> +		bt->il_vbackporch = hdmi_readl(dw_dev, HDMI_MD_VOL);
> +		bt->il_vfrontporch = vtot - bt->height - bt->il_vsync -
> +			bt->il_vbackporch;
> +
> +		hdmi_mask_writel(dw_dev, 0x0, HDMI_MD_VCTRL,
> +				HDMI_MD_VCTRL_V_MODE_OFFSET,
> +				HDMI_MD_VCTRL_V_MODE_MASK);

Same here, I'm not sure this is correct. What is the output of
'v4l2-ctl --query-dv-timings' when you feed it a standard interlaced format?

> +	}
> +
> +	bt->standards = V4L2_DV_BT_STD_CEA861;
> +
> +	vic = dw_hdmi_get_curr_vic(dw_dev, &is_hdmi_vic);
> +	if (vic) {
> +		if (is_hdmi_vic) {
> +			bt->flags |= V4L2_DV_FL_HAS_HDMI_VIC;
> +			bt->hdmi_vic = vic;
> +			bt->cea861_vic = 0;
> +		} else {
> +			bt->flags |= V4L2_DV_FL_HAS_CEA861_VIC;
> +			bt->hdmi_vic = 0;
> +			bt->cea861_vic = vic;
> +		}
> +	}
> +
> +	return 0;
> +}

Regards,

	Hans

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