Re: [PATCH v3 3/9] drm/i915/dp: Move vswing/pre-emphasis adjustment calculation

[Jani Nikula <jani.nikula@intel.com>]

On Mon, 30 Dec 2019, Animesh Manna <animesh.manna@intel.com> wrote:
> vswing/pre-emphasis adjustment calculation is needed in processing
> of auto phy compliance request other than link training, so moved
> the same function in intel_dp.c.

I guess I'm still asking why you think this is better located in
intel_dp.c than intel_dp_link_training.c, as the function has been moved
once in the other direction already to split out stuff from intel_dp.c
and to make the file smaller. Even the file name suggests it should
really be in intel_dp_link_training.c, right?

BR,
Jani.


>
> No functional change.
>
> v1: initial patch.
> v2:
> - used "intel_dp" prefix in function name. (Jani)
> - used array notation instead pointer for link_status. (Ville)
>
> Signed-off-by: Animesh Manna <animesh.manna@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c       | 34 ++++++++++++++++++
>  drivers/gpu/drm/i915/display/intel_dp.h       |  4 +++
>  .../drm/i915/display/intel_dp_link_training.c | 36 ++-----------------
>  3 files changed, 40 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 991f343579ef..2a27ee106089 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -4110,6 +4110,40 @@ ivb_cpu_edp_signal_levels(u8 train_set)
>  	}
>  }
>  
> +void
> +intel_dp_get_adjust_train(struct intel_dp *intel_dp,
> +			  const u8 link_status[DP_LINK_STATUS_SIZE])
> +{
> +	u8 v = 0;
> +	u8 p = 0;
> +	int lane;
> +	u8 voltage_max;
> +	u8 preemph_max;
> +
> +	for (lane = 0; lane < intel_dp->lane_count; lane++) {
> +		u8 this_v = drm_dp_get_adjust_request_voltage(link_status,
> +							      lane);
> +		u8 this_p = drm_dp_get_adjust_request_pre_emphasis(link_status,
> +								   lane);
> +
> +		if (this_v > v)
> +			v = this_v;
> +		if (this_p > p)
> +			p = this_p;
> +	}
> +
> +	voltage_max = intel_dp_voltage_max(intel_dp);
> +	if (v >= voltage_max)
> +		v = voltage_max | DP_TRAIN_MAX_SWING_REACHED;
> +
> +	preemph_max = intel_dp_pre_emphasis_max(intel_dp, v);
> +	if (p >= preemph_max)
> +		p = preemph_max | DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
> +
> +	for (lane = 0; lane < 4; lane++)
> +		intel_dp->train_set[lane] = v | p;
> +}
> +
>  void
>  intel_dp_set_signal_levels(struct intel_dp *intel_dp)
>  {
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
> index 3da166054788..83eadc87af26 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.h
> +++ b/drivers/gpu/drm/i915/display/intel_dp.h
> @@ -9,6 +9,7 @@
>  #include <linux/types.h>
>  
>  #include <drm/i915_drm.h>
> +#include <drm/drm_dp_helper.h>
>  
>  #include "i915_reg.h"
>  
> @@ -91,6 +92,9 @@ void
>  intel_dp_program_link_training_pattern(struct intel_dp *intel_dp,
>  				       u8 dp_train_pat);
>  void
> +intel_dp_get_adjust_train(struct intel_dp *intel_dp,
> +			  const u8 link_status[DP_LINK_STATUS_SIZE]);
> +void
>  intel_dp_set_signal_levels(struct intel_dp *intel_dp);
>  void intel_dp_set_idle_link_train(struct intel_dp *intel_dp);
>  u8
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> index 2a1130dd1ad0..e8ff9e279800 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> @@ -34,38 +34,6 @@ intel_dp_dump_link_status(const u8 link_status[DP_LINK_STATUS_SIZE])
>  		      link_status[3], link_status[4], link_status[5]);
>  }
>  
> -static void
> -intel_get_adjust_train(struct intel_dp *intel_dp,
> -		       const u8 link_status[DP_LINK_STATUS_SIZE])
> -{
> -	u8 v = 0;
> -	u8 p = 0;
> -	int lane;
> -	u8 voltage_max;
> -	u8 preemph_max;
> -
> -	for (lane = 0; lane < intel_dp->lane_count; lane++) {
> -		u8 this_v = drm_dp_get_adjust_request_voltage(link_status, lane);
> -		u8 this_p = drm_dp_get_adjust_request_pre_emphasis(link_status, lane);
> -
> -		if (this_v > v)
> -			v = this_v;
> -		if (this_p > p)
> -			p = this_p;
> -	}
> -
> -	voltage_max = intel_dp_voltage_max(intel_dp);
> -	if (v >= voltage_max)
> -		v = voltage_max | DP_TRAIN_MAX_SWING_REACHED;
> -
> -	preemph_max = intel_dp_pre_emphasis_max(intel_dp, v);
> -	if (p >= preemph_max)
> -		p = preemph_max | DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
> -
> -	for (lane = 0; lane < 4; lane++)
> -		intel_dp->train_set[lane] = v | p;
> -}
> -
>  static bool
>  intel_dp_set_link_train(struct intel_dp *intel_dp,
>  			u8 dp_train_pat)
> @@ -215,7 +183,7 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
>  		voltage = intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
>  
>  		/* Update training set as requested by target */
> -		intel_get_adjust_train(intel_dp, link_status);
> +		intel_dp_get_adjust_train(intel_dp, link_status);
>  		if (!intel_dp_update_link_train(intel_dp)) {
>  			DRM_ERROR("failed to update link training\n");
>  			return false;
> @@ -325,7 +293,7 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
>  		}
>  
>  		/* Update training set as requested by target */
> -		intel_get_adjust_train(intel_dp, link_status);
> +		intel_dp_get_adjust_train(intel_dp, link_status);
>  		if (!intel_dp_update_link_train(intel_dp)) {
>  			DRM_ERROR("failed to update link training\n");
>  			break;

-- 
Jani Nikula, Intel Open Source Graphics Center
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