diff mbox series

[2/3] drm/msm/dp: Remove pixel_rate from struct dp_ctrl

Message ID 20220617204750.2347797-3-swboyd@chromium.org (mailing list archive)
State New, archived
Headers show
Series drm/msm/dp: More cleanups for force link train | expand

Commit Message

Stephen Boyd June 17, 2022, 8:47 p.m. UTC
This struct member is stored to in the function that calls the function
which uses it. That's possible with a function argument instead of
storing to a struct member. Pass the pixel_rate as an argument instead
to simplify the code. Note that dp_ctrl_link_maintenance() was storing
the pixel_rate but never using it so we just remove the assignment from
there.

Cc: Kuogee Hsieh <quic_khsieh@quicinc.com>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---
 drivers/gpu/drm/msm/dp/dp_ctrl.c | 57 ++++++++++++++++----------------
 drivers/gpu/drm/msm/dp/dp_ctrl.h |  1 -
 2 files changed, 28 insertions(+), 30 deletions(-)

Comments

Dmitry Baryshkov June 17, 2022, 11:07 p.m. UTC | #1
On 17/06/2022 23:47, Stephen Boyd wrote:
> This struct member is stored to in the function that calls the function
> which uses it. That's possible with a function argument instead of
> storing to a struct member. Pass the pixel_rate as an argument instead
> to simplify the code. Note that dp_ctrl_link_maintenance() was storing
> the pixel_rate but never using it so we just remove the assignment from
> there.
> 
> Cc: Kuogee Hsieh <quic_khsieh@quicinc.com>
> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
> ---
>   drivers/gpu/drm/msm/dp/dp_ctrl.c | 57 ++++++++++++++++----------------
>   drivers/gpu/drm/msm/dp/dp_ctrl.h |  1 -
>   2 files changed, 28 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> index bd445e683cfc..e114521af2e9 100644
> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> @@ -1336,7 +1336,7 @@ static void dp_ctrl_set_clock_rate(struct dp_ctrl_private *ctrl,
>   				name, rate);
>   }
>   
> -static int dp_ctrl_enable_mainlink_clocks(struct dp_ctrl_private *ctrl)
> +static int dp_ctrl_enable_mainlink_clocks(struct dp_ctrl_private *ctrl, unsigned long pixel_rate)


I think we can read pixel_rate here rather than getting it as an 
argument. We'd need to move handling (DP_TEST_LINK_PHY_TEST_PATTERN && 
!ctrl->panel->dp_mode.drm_mode.clock) case here from dp_ctrl_on_link().

>   {
>   	int ret = 0;
>   	struct dp_io *dp_io = &ctrl->parser->io;
> @@ -1357,25 +1357,25 @@ static int dp_ctrl_enable_mainlink_clocks(struct dp_ctrl_private *ctrl)
>   	if (ret)
>   		DRM_ERROR("Unable to start link clocks. ret=%d\n", ret);
>   
> -	drm_dbg_dp(ctrl->drm_dev, "link rate=%d pixel_clk=%d\n",
> -		ctrl->link->link_params.rate, ctrl->dp_ctrl.pixel_rate);
> +	drm_dbg_dp(ctrl->drm_dev, "link rate=%d pixel_clk=%lu\n",
> +		ctrl->link->link_params.rate, pixel_rate);
>   
>   	return ret;
>   }
>   
> -static int dp_ctrl_enable_stream_clocks(struct dp_ctrl_private *ctrl)
> +static int dp_ctrl_enable_stream_clocks(struct dp_ctrl_private *ctrl,
> +					unsigned long pixel_rate)
>   {
> -	int ret = 0;
> +	int ret;
>   
> -	dp_ctrl_set_clock_rate(ctrl, DP_STREAM_PM, "stream_pixel",
> -					ctrl->dp_ctrl.pixel_rate * 1000);
> +	dp_ctrl_set_clock_rate(ctrl, DP_STREAM_PM, "stream_pixel", pixel_rate * 1000);

Note to myself (or to anybody doing further cleanup): store stream_pixel 
clock into dp_ctrl_private and set it directly here. Then 
dp_ctrl_set_clock_rate() can be removed.

>   
>   	ret = dp_power_clk_enable(ctrl->power, DP_STREAM_PM, true);
>   	if (ret)
>   		DRM_ERROR("Unabled to start pixel clocks. ret=%d\n", ret);
>   
> -	drm_dbg_dp(ctrl->drm_dev, "link rate=%d pixel_clk=%d\n",
> -			ctrl->link->link_params.rate, ctrl->dp_ctrl.pixel_rate);
> +	drm_dbg_dp(ctrl->drm_dev, "link rate=%d pixel_clk=%lu\n",
> +			ctrl->link->link_params.rate, pixel_rate);
>   
>   	return ret;
>   }
> @@ -1445,7 +1445,7 @@ static bool dp_ctrl_use_fixed_nvid(struct dp_ctrl_private *ctrl)
>   	return false;
>   }
>   
> -static int dp_ctrl_reinitialize_mainlink(struct dp_ctrl_private *ctrl)
> +static int dp_ctrl_reinitialize_mainlink(struct dp_ctrl_private *ctrl, unsigned long pixel_rate)
>   {
>   	int ret = 0;
>   	struct dp_io *dp_io = &ctrl->parser->io;
> @@ -1469,7 +1469,7 @@ static int dp_ctrl_reinitialize_mainlink(struct dp_ctrl_private *ctrl)
>   	/* hw recommended delay before re-enabling clocks */
>   	msleep(20);
>   
> -	ret = dp_ctrl_enable_mainlink_clocks(ctrl);
> +	ret = dp_ctrl_enable_mainlink_clocks(ctrl, pixel_rate);
>   	if (ret) {
>   		DRM_ERROR("Failed to enable mainlink clks. ret=%d\n", ret);
>   		return ret;
> @@ -1517,8 +1517,6 @@ static int dp_ctrl_link_maintenance(struct dp_ctrl_private *ctrl)
>   	ctrl->link->phy_params.p_level = 0;
>   	ctrl->link->phy_params.v_level = 0;
>   
> -	ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
> -
>   	ret = dp_ctrl_setup_main_link(ctrl, &training_step);
>   	if (ret)
>   		goto end;
> @@ -1588,12 +1586,12 @@ static int dp_ctrl_on_stream_phy_test_report(struct dp_ctrl *dp_ctrl)
>   {
>   	int ret;
>   	struct dp_ctrl_private *ctrl;
> +	unsigned long pixel_rate;
>   
>   	ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
>   
> -	ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
> -
> -	ret = dp_ctrl_enable_stream_clocks(ctrl);
> +	pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
> +	ret = dp_ctrl_enable_stream_clocks(ctrl, pixel_rate);

I think we can take another step forward here. Read the 
ctrl->panel->dp_mode.drm_mode.clock from within the 
dp_ctrl_enable_stream_clocks() function. This removes the need to pass 
pixel_rate as an argument here.

>   	if (ret) {
>   		DRM_ERROR("Failed to start pixel clocks. ret=%d\n", ret);
>   		return ret;
> @@ -1709,6 +1707,7 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
>   	u32 const phy_cts_pixel_clk_khz = 148500;
>   	u8 link_status[DP_LINK_STATUS_SIZE];
>   	unsigned int training_step;
> +	unsigned long pixel_rate;
>   
>   	if (!dp_ctrl)
>   		return -EINVAL;
> @@ -1723,25 +1722,25 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
>   		drm_dbg_dp(ctrl->drm_dev,
>   				"using phy test link parameters\n");
>   		if (!ctrl->panel->dp_mode.drm_mode.clock)
> -			ctrl->dp_ctrl.pixel_rate = phy_cts_pixel_clk_khz;
> +			pixel_rate = phy_cts_pixel_clk_khz;
>   	} else {
>   		ctrl->link->link_params.rate = rate;
>   		ctrl->link->link_params.num_lanes =
>   			ctrl->panel->link_info.num_lanes;
> -		ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
> +		pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
>   	}
>   
> -	drm_dbg_dp(ctrl->drm_dev, "rate=%d, num_lanes=%d, pixel_rate=%d\n",
> +	drm_dbg_dp(ctrl->drm_dev, "rate=%d, num_lanes=%d, pixel_rate=%lu\n",
>   		ctrl->link->link_params.rate, ctrl->link->link_params.num_lanes,
> -		ctrl->dp_ctrl.pixel_rate);
> +		pixel_rate);
>   
>   
> -	rc = dp_ctrl_enable_mainlink_clocks(ctrl);
> +	rc = dp_ctrl_enable_mainlink_clocks(ctrl, pixel_rate);
>   	if (rc)
>   		return rc;
>   
>   	while (--link_train_max_retries) {
> -		rc = dp_ctrl_reinitialize_mainlink(ctrl);
> +		rc = dp_ctrl_reinitialize_mainlink(ctrl, pixel_rate);
>   		if (rc) {
>   			DRM_ERROR("Failed to reinitialize mainlink. rc=%d\n",
>   					rc);
> @@ -1836,6 +1835,7 @@ int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl, bool force_link_train)
>   	int ret = 0;
>   	bool mainlink_ready = false;
>   	struct dp_ctrl_private *ctrl;
> +	unsigned long pixel_rate;
>   	unsigned long pixel_rate_orig;
>   
>   	if (!dp_ctrl)
> @@ -1843,25 +1843,24 @@ int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl, bool force_link_train)
>   
>   	ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
>   
> -	ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
> +	pixel_rate = pixel_rate_orig = ctrl->panel->dp_mode.drm_mode.clock;
>   
> -	pixel_rate_orig = ctrl->dp_ctrl.pixel_rate;
>   	if (dp_ctrl->wide_bus_en)
> -		ctrl->dp_ctrl.pixel_rate >>= 1;
> +		pixel_rate >>= 1;
>   
> -	drm_dbg_dp(ctrl->drm_dev, "rate=%d, num_lanes=%d, pixel_rate=%d\n",
> +	drm_dbg_dp(ctrl->drm_dev, "rate=%d, num_lanes=%d, pixel_rate=%lu\n",
>   		ctrl->link->link_params.rate,
> -		ctrl->link->link_params.num_lanes, ctrl->dp_ctrl.pixel_rate);
> +		ctrl->link->link_params.num_lanes, pixel_rate);
>   
>   	if (!dp_power_clk_status(ctrl->power, DP_CTRL_PM)) { /* link clk is off */
> -		ret = dp_ctrl_enable_mainlink_clocks(ctrl);
> +		ret = dp_ctrl_enable_mainlink_clocks(ctrl, pixel_rate);
>   		if (ret) {
>   			DRM_ERROR("Failed to start link clocks. ret=%d\n", ret);
>   			goto end;
>   		}
>   	}
>   
> -	ret = dp_ctrl_enable_stream_clocks(ctrl);
> +	ret = dp_ctrl_enable_stream_clocks(ctrl, pixel_rate);
>   	if (ret) {
>   		DRM_ERROR("Failed to start pixel clocks. ret=%d\n", ret);
>   		goto end;
> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.h b/drivers/gpu/drm/msm/dp/dp_ctrl.h
> index b563e2e3bfe5..9f29734af81c 100644
> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.h
> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.h
> @@ -16,7 +16,6 @@
>   struct dp_ctrl {
>   	bool orientation;
>   	atomic_t aborted;
> -	u32 pixel_rate;
>   	bool wide_bus_en;
>   };
>
Stephen Boyd June 22, 2022, 2:59 a.m. UTC | #2
Quoting Dmitry Baryshkov (2022-06-17 16:07:58)
> On 17/06/2022 23:47, Stephen Boyd wrote:
> > This struct member is stored to in the function that calls the function
> > which uses it. That's possible with a function argument instead of
> > storing to a struct member. Pass the pixel_rate as an argument instead
> > to simplify the code. Note that dp_ctrl_link_maintenance() was storing
> > the pixel_rate but never using it so we just remove the assignment from
> > there.
> >
> > Cc: Kuogee Hsieh <quic_khsieh@quicinc.com>
> > Signed-off-by: Stephen Boyd <swboyd@chromium.org>
> > ---
> >   drivers/gpu/drm/msm/dp/dp_ctrl.c | 57 ++++++++++++++++----------------
> >   drivers/gpu/drm/msm/dp/dp_ctrl.h |  1 -
> >   2 files changed, 28 insertions(+), 30 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > index bd445e683cfc..e114521af2e9 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > @@ -1336,7 +1336,7 @@ static void dp_ctrl_set_clock_rate(struct dp_ctrl_private *ctrl,
> >                               name, rate);
> >   }
> >
> > -static int dp_ctrl_enable_mainlink_clocks(struct dp_ctrl_private *ctrl)
> > +static int dp_ctrl_enable_mainlink_clocks(struct dp_ctrl_private *ctrl, unsigned long pixel_rate)
>
>
> I think we can read pixel_rate here rather than getting it as an
> argument. We'd need to move handling (DP_TEST_LINK_PHY_TEST_PATTERN &&
> !ctrl->panel->dp_mode.drm_mode.clock) case here from dp_ctrl_on_link().

This is also called from dp_ctrl_on_stream() and
dp_ctrl_reinitialize_mainlink(). In the dp_ctrl_on_stream() case we may
divide the pixel_rate by 2 with widebus. We could move the
dp_ctrl_on_link() code here, but then we also need to move widebus, and
then I'm not sure which pixel rate to use.

It looks like the test code doesn't care about widebus? And similarly,
we may run the pixel clk faster until we get a modeset and then divide
it for widebus. Is that why you're suggesting to check
!ctrl->panel->dp_mode.drm_mode.clock? I hesitate because it isn't a
direct conversion, instead it checks some other stashed struct member.

I'll also note that dp_ctrl_enable_mainlink_clocks() doesn't really use
this argument except to print the value in drm_dbg_dp(). Maybe we should
simply remove it from here instead?

> > @@ -1588,12 +1586,12 @@ static int dp_ctrl_on_stream_phy_test_report(struct dp_ctrl *dp_ctrl)
> >   {
> >       int ret;
> >       struct dp_ctrl_private *ctrl;
> > +     unsigned long pixel_rate;
> >
> >       ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
> >
> > -     ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
> > -
> > -     ret = dp_ctrl_enable_stream_clocks(ctrl);
> > +     pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
> > +     ret = dp_ctrl_enable_stream_clocks(ctrl, pixel_rate);
>
> I think we can take another step forward here. Read the
> ctrl->panel->dp_mode.drm_mode.clock from within the
> dp_ctrl_enable_stream_clocks() function. This removes the need to pass
> pixel_rate as an argument here.

This is also affected by widebus and if the function is called from
dp_ctrl_on_stream() or dp_ctrl_on_stream_phy_test_report(). Maybe it
would be better to inline dp_ctrl_enable_stream_clocks() to the
callsites? That would probably simplify things because the function is
mostly a wrapper around a couple functions.
Dmitry Baryshkov June 22, 2022, 7:24 a.m. UTC | #3
On 22/06/2022 05:59, Stephen Boyd wrote:
> Quoting Dmitry Baryshkov (2022-06-17 16:07:58)
>> On 17/06/2022 23:47, Stephen Boyd wrote:
>>> This struct member is stored to in the function that calls the function
>>> which uses it. That's possible with a function argument instead of
>>> storing to a struct member. Pass the pixel_rate as an argument instead
>>> to simplify the code. Note that dp_ctrl_link_maintenance() was storing
>>> the pixel_rate but never using it so we just remove the assignment from
>>> there.
>>>
>>> Cc: Kuogee Hsieh <quic_khsieh@quicinc.com>
>>> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
>>> ---
>>>    drivers/gpu/drm/msm/dp/dp_ctrl.c | 57 ++++++++++++++++----------------
>>>    drivers/gpu/drm/msm/dp/dp_ctrl.h |  1 -
>>>    2 files changed, 28 insertions(+), 30 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
>>> index bd445e683cfc..e114521af2e9 100644
>>> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
>>> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
>>> @@ -1336,7 +1336,7 @@ static void dp_ctrl_set_clock_rate(struct dp_ctrl_private *ctrl,
>>>                                name, rate);
>>>    }
>>>
>>> -static int dp_ctrl_enable_mainlink_clocks(struct dp_ctrl_private *ctrl)
>>> +static int dp_ctrl_enable_mainlink_clocks(struct dp_ctrl_private *ctrl, unsigned long pixel_rate)
>>
>>
>> I think we can read pixel_rate here rather than getting it as an
>> argument. We'd need to move handling (DP_TEST_LINK_PHY_TEST_PATTERN &&
>> !ctrl->panel->dp_mode.drm_mode.clock) case here from dp_ctrl_on_link().
> 
> This is also called from dp_ctrl_on_stream() and
> dp_ctrl_reinitialize_mainlink(). In the dp_ctrl_on_stream() case we may
> divide the pixel_rate by 2 with widebus. We could move the
> dp_ctrl_on_link() code here, but then we also need to move widebus, and
> then I'm not sure which pixel rate to use.
> 
> It looks like the test code doesn't care about widebus? And similarly,
> we may run the pixel clk faster until we get a modeset and then divide
> it for widebus.

Good question. I'll let Kuogee or somebody else from Qualcomm to comment 
on test code vs widebus vs pixel rate, as I don't know these details.

I'm not sure if we should halve the pixel clock in 
dp_ctrl_on_stream_phy_test_report() or not if the widebus is supported.
 From the current code I'd assume that we have to do this. Let's raise 
this question in the corresponding patch discussion.

> Is that why you're suggesting to check
> !ctrl->panel->dp_mode.drm_mode.clock? I hesitate because it isn't a
> direct conversion, instead it checks some other stashed struct member.
> 
> I'll also note that dp_ctrl_enable_mainlink_clocks() doesn't really use
> this argument except to print the value in drm_dbg_dp(). Maybe we should
> simply remove it from here instead?

Yes, do it please.

> 
>>> @@ -1588,12 +1586,12 @@ static int dp_ctrl_on_stream_phy_test_report(struct dp_ctrl *dp_ctrl)
>>>    {
>>>        int ret;
>>>        struct dp_ctrl_private *ctrl;
>>> +     unsigned long pixel_rate;
>>>
>>>        ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
>>>
>>> -     ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
>>> -
>>> -     ret = dp_ctrl_enable_stream_clocks(ctrl);
>>> +     pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
>>> +     ret = dp_ctrl_enable_stream_clocks(ctrl, pixel_rate);
>>
>> I think we can take another step forward here. Read the
>> ctrl->panel->dp_mode.drm_mode.clock from within the
>> dp_ctrl_enable_stream_clocks() function. This removes the need to pass
>> pixel_rate as an argument here.
> 
> This is also affected by widebus and if the function is called from
> dp_ctrl_on_stream() or dp_ctrl_on_stream_phy_test_report(). Maybe it
> would be better to inline dp_ctrl_enable_stream_clocks() to the
> callsites? That would probably simplify things because the function is
> mostly a wrapper around a couple functions.

Yes, this sounds good. Then we can drop the drm_dbg_dp from it (as it 
nearly duplicates the data that was just printed.
Kuogee Hsieh June 22, 2022, 3:22 p.m. UTC | #4
On 6/22/2022 12:24 AM, Dmitry Baryshkov wrote:
> On 22/06/2022 05:59, Stephen Boyd wrote:
>> Quoting Dmitry Baryshkov (2022-06-17 16:07:58)
>>> On 17/06/2022 23:47, Stephen Boyd wrote:
>>>> This struct member is stored to in the function that calls the 
>>>> function
>>>> which uses it. That's possible with a function argument instead of
>>>> storing to a struct member. Pass the pixel_rate as an argument instead
>>>> to simplify the code. Note that dp_ctrl_link_maintenance() was storing
>>>> the pixel_rate but never using it so we just remove the assignment 
>>>> from
>>>> there.
>>>>
>>>> Cc: Kuogee Hsieh <quic_khsieh@quicinc.com>
>>>> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
>>>> ---
>>>>    drivers/gpu/drm/msm/dp/dp_ctrl.c | 57 
>>>> ++++++++++++++++----------------
>>>>    drivers/gpu/drm/msm/dp/dp_ctrl.h |  1 -
>>>>    2 files changed, 28 insertions(+), 30 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c 
>>>> b/drivers/gpu/drm/msm/dp/dp_ctrl.c
>>>> index bd445e683cfc..e114521af2e9 100644
>>>> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
>>>> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
>>>> @@ -1336,7 +1336,7 @@ static void dp_ctrl_set_clock_rate(struct 
>>>> dp_ctrl_private *ctrl,
>>>>                                name, rate);
>>>>    }
>>>>
>>>> -static int dp_ctrl_enable_mainlink_clocks(struct dp_ctrl_private 
>>>> *ctrl)
>>>> +static int dp_ctrl_enable_mainlink_clocks(struct dp_ctrl_private 
>>>> *ctrl, unsigned long pixel_rate)
>>>
>>>
>>> I think we can read pixel_rate here rather than getting it as an
>>> argument. We'd need to move handling (DP_TEST_LINK_PHY_TEST_PATTERN &&
>>> !ctrl->panel->dp_mode.drm_mode.clock) case here from dp_ctrl_on_link().
>>
>> This is also called from dp_ctrl_on_stream() and
>> dp_ctrl_reinitialize_mainlink(). In the dp_ctrl_on_stream() case we may
>> divide the pixel_rate by 2 with widebus. We could move the
>> dp_ctrl_on_link() code here, but then we also need to move widebus, and
>> then I'm not sure which pixel rate to use.
>>
>> It looks like the test code doesn't care about widebus? And similarly,
>> we may run the pixel clk faster until we get a modeset and then divide
>> it for widebus.
>
> Good question. I'll let Kuogee or somebody else from Qualcomm to 
> comment on test code vs widebus vs pixel rate, as I don't know these 
> details.
>
> I'm not sure if we should halve the pixel clock in 
> dp_ctrl_on_stream_phy_test_report() or not if the widebus is supported.
> From the current code I'd assume that we have to do this. Let's raise 
> this question in the corresponding patch discussion.
>
yes, phy test does not care pixel clock rate.
>> Is that why you're suggesting to check
>> !ctrl->panel->dp_mode.drm_mode.clock? I hesitate because it isn't a
>> direct conversion, instead it checks some other stashed struct member.
>>
>> I'll also note that dp_ctrl_enable_mainlink_clocks() doesn't really use
>> this argument except to print the value in drm_dbg_dp(). Maybe we should
>> simply remove it from here instead?
>
> Yes, do it please.
>
>>
>>>> @@ -1588,12 +1586,12 @@ static int 
>>>> dp_ctrl_on_stream_phy_test_report(struct dp_ctrl *dp_ctrl)
>>>>    {
>>>>        int ret;
>>>>        struct dp_ctrl_private *ctrl;
>>>> +     unsigned long pixel_rate;
>>>>
>>>>        ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
>>>>
>>>> -     ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
>>>> -
>>>> -     ret = dp_ctrl_enable_stream_clocks(ctrl);
>>>> +     pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
>>>> +     ret = dp_ctrl_enable_stream_clocks(ctrl, pixel_rate);
>>>
>>> I think we can take another step forward here. Read the
>>> ctrl->panel->dp_mode.drm_mode.clock from within the
>>> dp_ctrl_enable_stream_clocks() function. This removes the need to pass
>>> pixel_rate as an argument here.
>>
>> This is also affected by widebus and if the function is called from
>> dp_ctrl_on_stream() or dp_ctrl_on_stream_phy_test_report(). Maybe it
>> would be better to inline dp_ctrl_enable_stream_clocks() to the
>> callsites? That would probably simplify things because the function is
>> mostly a wrapper around a couple functions.
>
> Yes, this sounds good. Then we can drop the drm_dbg_dp from it (as it 
> nearly duplicates the data that was just printed.
>
>
Dmitry Baryshkov June 22, 2022, 5:58 p.m. UTC | #5
On 22/06/2022 18:22, Kuogee Hsieh wrote:
> 
> On 6/22/2022 12:24 AM, Dmitry Baryshkov wrote:
>> On 22/06/2022 05:59, Stephen Boyd wrote:
>>> Quoting Dmitry Baryshkov (2022-06-17 16:07:58)
>>>> On 17/06/2022 23:47, Stephen Boyd wrote:
>>>>> This struct member is stored to in the function that calls the 
>>>>> function
>>>>> which uses it. That's possible with a function argument instead of
>>>>> storing to a struct member. Pass the pixel_rate as an argument instead
>>>>> to simplify the code. Note that dp_ctrl_link_maintenance() was storing
>>>>> the pixel_rate but never using it so we just remove the assignment 
>>>>> from
>>>>> there.
>>>>>
>>>>> Cc: Kuogee Hsieh <quic_khsieh@quicinc.com>
>>>>> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
>>>>> ---
>>>>>    drivers/gpu/drm/msm/dp/dp_ctrl.c | 57 
>>>>> ++++++++++++++++----------------
>>>>>    drivers/gpu/drm/msm/dp/dp_ctrl.h |  1 -
>>>>>    2 files changed, 28 insertions(+), 30 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c 
>>>>> b/drivers/gpu/drm/msm/dp/dp_ctrl.c
>>>>> index bd445e683cfc..e114521af2e9 100644
>>>>> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
>>>>> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
>>>>> @@ -1336,7 +1336,7 @@ static void dp_ctrl_set_clock_rate(struct 
>>>>> dp_ctrl_private *ctrl,
>>>>>                                name, rate);
>>>>>    }
>>>>>
>>>>> -static int dp_ctrl_enable_mainlink_clocks(struct dp_ctrl_private 
>>>>> *ctrl)
>>>>> +static int dp_ctrl_enable_mainlink_clocks(struct dp_ctrl_private 
>>>>> *ctrl, unsigned long pixel_rate)
>>>>
>>>>
>>>> I think we can read pixel_rate here rather than getting it as an
>>>> argument. We'd need to move handling (DP_TEST_LINK_PHY_TEST_PATTERN &&
>>>> !ctrl->panel->dp_mode.drm_mode.clock) case here from dp_ctrl_on_link().
>>>
>>> This is also called from dp_ctrl_on_stream() and
>>> dp_ctrl_reinitialize_mainlink(). In the dp_ctrl_on_stream() case we may
>>> divide the pixel_rate by 2 with widebus. We could move the
>>> dp_ctrl_on_link() code here, but then we also need to move widebus, and
>>> then I'm not sure which pixel rate to use.
>>>
>>> It looks like the test code doesn't care about widebus? And similarly,
>>> we may run the pixel clk faster until we get a modeset and then divide
>>> it for widebus.
>>
>> Good question. I'll let Kuogee or somebody else from Qualcomm to 
>> comment on test code vs widebus vs pixel rate, as I don't know these 
>> details.
>>
>> I'm not sure if we should halve the pixel clock in 
>> dp_ctrl_on_stream_phy_test_report() or not if the widebus is supported.
>> From the current code I'd assume that we have to do this. Let's raise 
>> this question in the corresponding patch discussion.
>>
> yes, phy test does not care pixel clock rate.

So, is it 'does not care' or 'set to mode clock'?

In other words, can we unify both functions by always accounting for the 
wide_bus_en value?
diff mbox series

Patch

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index bd445e683cfc..e114521af2e9 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1336,7 +1336,7 @@  static void dp_ctrl_set_clock_rate(struct dp_ctrl_private *ctrl,
 				name, rate);
 }
 
-static int dp_ctrl_enable_mainlink_clocks(struct dp_ctrl_private *ctrl)
+static int dp_ctrl_enable_mainlink_clocks(struct dp_ctrl_private *ctrl, unsigned long pixel_rate)
 {
 	int ret = 0;
 	struct dp_io *dp_io = &ctrl->parser->io;
@@ -1357,25 +1357,25 @@  static int dp_ctrl_enable_mainlink_clocks(struct dp_ctrl_private *ctrl)
 	if (ret)
 		DRM_ERROR("Unable to start link clocks. ret=%d\n", ret);
 
-	drm_dbg_dp(ctrl->drm_dev, "link rate=%d pixel_clk=%d\n",
-		ctrl->link->link_params.rate, ctrl->dp_ctrl.pixel_rate);
+	drm_dbg_dp(ctrl->drm_dev, "link rate=%d pixel_clk=%lu\n",
+		ctrl->link->link_params.rate, pixel_rate);
 
 	return ret;
 }
 
-static int dp_ctrl_enable_stream_clocks(struct dp_ctrl_private *ctrl)
+static int dp_ctrl_enable_stream_clocks(struct dp_ctrl_private *ctrl,
+					unsigned long pixel_rate)
 {
-	int ret = 0;
+	int ret;
 
-	dp_ctrl_set_clock_rate(ctrl, DP_STREAM_PM, "stream_pixel",
-					ctrl->dp_ctrl.pixel_rate * 1000);
+	dp_ctrl_set_clock_rate(ctrl, DP_STREAM_PM, "stream_pixel", pixel_rate * 1000);
 
 	ret = dp_power_clk_enable(ctrl->power, DP_STREAM_PM, true);
 	if (ret)
 		DRM_ERROR("Unabled to start pixel clocks. ret=%d\n", ret);
 
-	drm_dbg_dp(ctrl->drm_dev, "link rate=%d pixel_clk=%d\n",
-			ctrl->link->link_params.rate, ctrl->dp_ctrl.pixel_rate);
+	drm_dbg_dp(ctrl->drm_dev, "link rate=%d pixel_clk=%lu\n",
+			ctrl->link->link_params.rate, pixel_rate);
 
 	return ret;
 }
@@ -1445,7 +1445,7 @@  static bool dp_ctrl_use_fixed_nvid(struct dp_ctrl_private *ctrl)
 	return false;
 }
 
-static int dp_ctrl_reinitialize_mainlink(struct dp_ctrl_private *ctrl)
+static int dp_ctrl_reinitialize_mainlink(struct dp_ctrl_private *ctrl, unsigned long pixel_rate)
 {
 	int ret = 0;
 	struct dp_io *dp_io = &ctrl->parser->io;
@@ -1469,7 +1469,7 @@  static int dp_ctrl_reinitialize_mainlink(struct dp_ctrl_private *ctrl)
 	/* hw recommended delay before re-enabling clocks */
 	msleep(20);
 
-	ret = dp_ctrl_enable_mainlink_clocks(ctrl);
+	ret = dp_ctrl_enable_mainlink_clocks(ctrl, pixel_rate);
 	if (ret) {
 		DRM_ERROR("Failed to enable mainlink clks. ret=%d\n", ret);
 		return ret;
@@ -1517,8 +1517,6 @@  static int dp_ctrl_link_maintenance(struct dp_ctrl_private *ctrl)
 	ctrl->link->phy_params.p_level = 0;
 	ctrl->link->phy_params.v_level = 0;
 
-	ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
-
 	ret = dp_ctrl_setup_main_link(ctrl, &training_step);
 	if (ret)
 		goto end;
@@ -1588,12 +1586,12 @@  static int dp_ctrl_on_stream_phy_test_report(struct dp_ctrl *dp_ctrl)
 {
 	int ret;
 	struct dp_ctrl_private *ctrl;
+	unsigned long pixel_rate;
 
 	ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
 
-	ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
-
-	ret = dp_ctrl_enable_stream_clocks(ctrl);
+	pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
+	ret = dp_ctrl_enable_stream_clocks(ctrl, pixel_rate);
 	if (ret) {
 		DRM_ERROR("Failed to start pixel clocks. ret=%d\n", ret);
 		return ret;
@@ -1709,6 +1707,7 @@  int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
 	u32 const phy_cts_pixel_clk_khz = 148500;
 	u8 link_status[DP_LINK_STATUS_SIZE];
 	unsigned int training_step;
+	unsigned long pixel_rate;
 
 	if (!dp_ctrl)
 		return -EINVAL;
@@ -1723,25 +1722,25 @@  int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
 		drm_dbg_dp(ctrl->drm_dev,
 				"using phy test link parameters\n");
 		if (!ctrl->panel->dp_mode.drm_mode.clock)
-			ctrl->dp_ctrl.pixel_rate = phy_cts_pixel_clk_khz;
+			pixel_rate = phy_cts_pixel_clk_khz;
 	} else {
 		ctrl->link->link_params.rate = rate;
 		ctrl->link->link_params.num_lanes =
 			ctrl->panel->link_info.num_lanes;
-		ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
+		pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
 	}
 
-	drm_dbg_dp(ctrl->drm_dev, "rate=%d, num_lanes=%d, pixel_rate=%d\n",
+	drm_dbg_dp(ctrl->drm_dev, "rate=%d, num_lanes=%d, pixel_rate=%lu\n",
 		ctrl->link->link_params.rate, ctrl->link->link_params.num_lanes,
-		ctrl->dp_ctrl.pixel_rate);
+		pixel_rate);
 
 
-	rc = dp_ctrl_enable_mainlink_clocks(ctrl);
+	rc = dp_ctrl_enable_mainlink_clocks(ctrl, pixel_rate);
 	if (rc)
 		return rc;
 
 	while (--link_train_max_retries) {
-		rc = dp_ctrl_reinitialize_mainlink(ctrl);
+		rc = dp_ctrl_reinitialize_mainlink(ctrl, pixel_rate);
 		if (rc) {
 			DRM_ERROR("Failed to reinitialize mainlink. rc=%d\n",
 					rc);
@@ -1836,6 +1835,7 @@  int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl, bool force_link_train)
 	int ret = 0;
 	bool mainlink_ready = false;
 	struct dp_ctrl_private *ctrl;
+	unsigned long pixel_rate;
 	unsigned long pixel_rate_orig;
 
 	if (!dp_ctrl)
@@ -1843,25 +1843,24 @@  int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl, bool force_link_train)
 
 	ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
 
-	ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
+	pixel_rate = pixel_rate_orig = ctrl->panel->dp_mode.drm_mode.clock;
 
-	pixel_rate_orig = ctrl->dp_ctrl.pixel_rate;
 	if (dp_ctrl->wide_bus_en)
-		ctrl->dp_ctrl.pixel_rate >>= 1;
+		pixel_rate >>= 1;
 
-	drm_dbg_dp(ctrl->drm_dev, "rate=%d, num_lanes=%d, pixel_rate=%d\n",
+	drm_dbg_dp(ctrl->drm_dev, "rate=%d, num_lanes=%d, pixel_rate=%lu\n",
 		ctrl->link->link_params.rate,
-		ctrl->link->link_params.num_lanes, ctrl->dp_ctrl.pixel_rate);
+		ctrl->link->link_params.num_lanes, pixel_rate);
 
 	if (!dp_power_clk_status(ctrl->power, DP_CTRL_PM)) { /* link clk is off */
-		ret = dp_ctrl_enable_mainlink_clocks(ctrl);
+		ret = dp_ctrl_enable_mainlink_clocks(ctrl, pixel_rate);
 		if (ret) {
 			DRM_ERROR("Failed to start link clocks. ret=%d\n", ret);
 			goto end;
 		}
 	}
 
-	ret = dp_ctrl_enable_stream_clocks(ctrl);
+	ret = dp_ctrl_enable_stream_clocks(ctrl, pixel_rate);
 	if (ret) {
 		DRM_ERROR("Failed to start pixel clocks. ret=%d\n", ret);
 		goto end;
diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.h b/drivers/gpu/drm/msm/dp/dp_ctrl.h
index b563e2e3bfe5..9f29734af81c 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.h
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.h
@@ -16,7 +16,6 @@ 
 struct dp_ctrl {
 	bool orientation;
 	atomic_t aborted;
-	u32 pixel_rate;
 	bool wide_bus_en;
 };