On Fri, May 12, 2023 at 02:17:48AM +0300, Vinod Govindapillai wrote:
> From MTL onwards, we need to find the best QGV point based on
> the required data rate and pass the peak BW of that point to
> the punit to lock the corresponding QGV point.
> 
> Bspec: 64636
> 
> Signed-off-by: Vinod Govindapillai <[email protected]>

Reviewed-by: Stanislav Lisovskiy <[email protected]>

> ---
>  drivers/gpu/drm/i915/display/intel_bw.c | 87 ++++++++++++++++++++++++-
>  drivers/gpu/drm/i915/display/intel_bw.h |  6 ++
>  2 files changed, 91 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_bw.c 
> b/drivers/gpu/drm/i915/display/intel_bw.c
> index f466b4e087bb..36b2f18dc0c1 100644
> --- a/drivers/gpu/drm/i915/display/intel_bw.c
> +++ b/drivers/gpu/drm/i915/display/intel_bw.c
> @@ -803,6 +803,85 @@ intel_atomic_get_bw_state(struct intel_atomic_state 
> *state)
>       return to_intel_bw_state(bw_state);
>  }
>  
> +static int mtl_find_qgv_points(struct drm_i915_private *i915,
> +                            unsigned int data_rate,
> +                            unsigned int num_active_planes,
> +                            const struct intel_bw_state *old_bw_state,
> +                            struct intel_bw_state *new_bw_state)
> +{
> +     unsigned int best_rate = UINT_MAX;
> +     unsigned int num_qgv_points = i915->display.bw.max[0].num_qgv_points;
> +     unsigned int qgv_peak_bw  = 0;
> +     int i;
> +     int ret;
> +
> +     ret = intel_atomic_lock_global_state(&new_bw_state->base);
> +     if (ret)
> +             return ret;
> +
> +     /*
> +      * If SAGV cannot be enabled, disable the pcode SAGV by passing all 1's
> +      * for qgv peak bw in PM Demand request. So assign UINT_MAX if SAGV is
> +      * not enabled. PM Demand code will clamp the value for the register
> +      */
> +     if (!intel_can_enable_sagv(i915, new_bw_state)) {
> +             new_bw_state->qgv_point_peakbw = UINT_MAX;
> +             drm_dbg_kms(&i915->drm, "No SAGV, use UINT_MAX as peak bw.");
> +             goto out;
> +     }
> +
> +     /*
> +      * Find the best QGV point by comparing the data_rate with max data rate
> +      * offered per plane group
> +      */
> +     for (i = 0; i < num_qgv_points; i++) {
> +             unsigned int bw_index =
> +                     tgl_max_bw_index(i915, num_active_planes, i);
> +             unsigned int max_data_rate;
> +
> +             if (bw_index > ARRAY_SIZE(i915->display.bw.max))
> +                     continue;
> +
> +             max_data_rate = i915->display.bw.max[bw_index].deratedbw[i];
> +
> +             if (max_data_rate < data_rate)
> +                     continue;
> +
> +             if (max_data_rate - data_rate < best_rate) {
> +                     best_rate = max_data_rate - data_rate;
> +                     qgv_peak_bw = i915->display.bw.max[bw_index].peakbw[i];
> +             }
> +
> +             drm_dbg_kms(&i915->drm, "QGV point %d: max bw %d required %d 
> qgv_peak_bw: %d\n",
> +                         i, max_data_rate, data_rate, qgv_peak_bw);
> +     }
> +
> +     drm_dbg_kms(&i915->drm, "Matching peaks QGV bw: %d for required data 
> rate: %d\n",
> +                 qgv_peak_bw, data_rate);
> +
> +     /*
> +      * The display configuration cannot be supported if no QGV point
> +      * satisfying the required data rate is found
> +      */
> +     if (qgv_peak_bw == 0) {
> +             drm_dbg_kms(&i915->drm, "No QGV points for bw %d for display 
> configuration(%d active planes).\n",
> +                         data_rate, num_active_planes);
> +             return -EINVAL;
> +     }
> +
> +     /* MTL PM DEMAND expects QGV BW parameter in multiples of 100 mbps */
> +     new_bw_state->qgv_point_peakbw = qgv_peak_bw / 100;
> +
> +out:
> +     if (new_bw_state->qgv_point_peakbw != old_bw_state->qgv_point_peakbw)  {
> +             ret = intel_atomic_serialize_global_state(&new_bw_state->base);
> +             if (ret)
> +                     return ret;
> +     }
> +
> +     return 0;
> +}
> +
>  static int icl_find_qgv_points(struct drm_i915_private *i915,
>                              unsigned int data_rate,
>                              unsigned int num_active_planes,
> @@ -928,8 +1007,12 @@ static int intel_bw_check_qgv_points(struct 
> drm_i915_private *i915,
>  
>       data_rate = DIV_ROUND_UP(data_rate, 1000);
>  
> -     return icl_find_qgv_points(i915, data_rate, num_active_planes,
> -                                old_bw_state, new_bw_state);
> +     if (DISPLAY_VER(i915) >= 14)
> +             return mtl_find_qgv_points(i915, data_rate, num_active_planes,
> +                                        old_bw_state, new_bw_state);
> +     else
> +             return icl_find_qgv_points(i915, data_rate, num_active_planes,
> +                                        old_bw_state, new_bw_state);
>  }
>  
>  static bool intel_bw_state_changed(struct drm_i915_private *i915,
> diff --git a/drivers/gpu/drm/i915/display/intel_bw.h 
> b/drivers/gpu/drm/i915/display/intel_bw.h
> index f20292143745..67ae66a3fcdd 100644
> --- a/drivers/gpu/drm/i915/display/intel_bw.h
> +++ b/drivers/gpu/drm/i915/display/intel_bw.h
> @@ -34,6 +34,12 @@ struct intel_bw_state {
>       /* bitmask of active pipes */
>       u8 active_pipes;
>  
> +     /*
> +      * From MTL onwards, to lock a QGV point, punit expects the peak BW of
> +      * the selected QGV point as the parameter in multiples of 100MB/s
> +      */
> +     unsigned int qgv_point_peakbw;
> +
>       /*
>        * Current QGV points mask, which restricts
>        * some particular SAGV states, not to confuse
> -- 
> 2.34.1
> 

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