Re: [PATCH 60/89] drm/i915/skl: CD clock back calculation for SKL

["M, Satheeshakrishna" <satheeshakrishna.m@intel.com>]

On 9/23/2014 12:49 AM, Paulo Zanoni wrote:
> 2014-09-04 8:27 GMT-03:00 Damien Lespiau<damien.lespiau@intel.com>:
>> From: Satheeshakrishna M<satheeshakrishna.m@intel.com>
>>
>> Determine programmed cd clock for SKL.
>>
>> v2: Fix the LCPLL1 enable warning logic
>>
>> v3: Rebase over the hsw pll rework.
>>
>> v4: Rebase on top of the per-platform split (Damien)
>>
>> Signed-off-by: Satheeshakrishna M<satheeshakrishna.m@intel.com>
>> Signed-off-by: Damien Lespiau<damien.lespiau@intel.com>
>> ---
>>   drivers/gpu/drm/i915/intel_ddi.c | 76 +++++++++++++++++++++++++++++++++++-----
>>   1 file changed, 67 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
>> index ba1103f..e7a5428 100644
>> --- a/drivers/gpu/drm/i915/intel_ddi.c
>> +++ b/drivers/gpu/drm/i915/intel_ddi.c
>> @@ -1260,6 +1260,55 @@ static void intel_disable_ddi(struct intel_encoder *intel_encoder)
>>          }
>>   }
>>
>> +static int skl_get_cdclk_freq(struct drm_i915_private *dev_priv)
>> +{
>> +       uint32_t lcpll1 = I915_READ(LCPLL1_CTL);
>> +       uint32_t cdctl = I915_READ(CDCLK_CTL);
>> +       uint32_t linkrate;
>> +
>> +       if (!(lcpll1 & LCPLL_PLL_ENABLE)) {
>> +               WARN(1, "LCPLL1 not enabled\n");
>> +               return 24000; /* 24MHz is the cd freq with NSSC ref */
>> +       }
>> +
>> +       if ((cdctl & CDCLK_FREQ_SEL_MASK) == CDCLK_FREQ_540)
>> +               return 540000;
>> +
>> +       linkrate = (I915_READ(DPLL_CTRL1) &
>> +                   DPLL_CRTL1_LINK_RATE_MASK(SKL_DPLL0)) >> 1;
>> +
>> +       if (linkrate == DPLL_CRTL1_LINK_RATE_2160 ||
>> +           linkrate == DPLL_CRTL1_LINK_RATE_1080) {
>> +               /* vco 8640 */
>> +               switch (cdctl & CDCLK_FREQ_SEL_MASK) {
>> +               case CDCLK_FREQ_450_432:
>> +                       return 432000;
>> +               case CDCLK_FREQ_337_308:
>> +                       return 308570;
>> +               case CDCLK_FREQ_675_617:
>> +                       return 617140;
>> +                       break;
> This is the only line with a "break" after a return :)
oops.. will remove it
>
>> +               default:
>> +                       WARN(1, "Unknown cd freq selection\n");
>> +               }
>> +       } else {
>> +               /* vco 8100 */
>> +               switch (cdctl & CDCLK_FREQ_SEL_MASK) {
>> +               case CDCLK_FREQ_450_432:
>> +                       return 450000;
>> +               case CDCLK_FREQ_337_308:
>> +                       return 337500;
>> +               case CDCLK_FREQ_675_617:
>> +                       return 675000;
>> +               default:
>> +                       WARN(1, "Unknown cd freq selection\n");
>> +               }
>> +       }
>> +
>> +       /* error case, do as if DPLL0 isn't enabled */
>> +       return 24000;
>> +}
>> +
>>   static int bdw_get_cdclk_freq(struct drm_i915_private *dev_priv)
>>   {
>>          uint32_t lcpll = I915_READ(LCPLL_CTL);
>> @@ -1301,6 +1350,9 @@ int intel_ddi_get_cdclk_freq(struct drm_i915_private *dev_priv)
>>   {
>>          struct drm_device *dev = dev_priv->dev;
>>
>> +       if (IS_SKYLAKE(dev))
>> +               return skl_get_cdclk_freq(dev_priv);
>> +
> I hope someone will replace this with a "switch (INTEL_INFO(gen))"
> before Gen 15 :)
>
> With or without changes: Reviewed-by: Paulo Zanoni<paulo.r.zanoni@intel.com>
>
>
>>          if (IS_BROADWELL(dev))
>>                  return bdw_get_cdclk_freq(dev_priv);
>>
>> @@ -1369,19 +1421,25 @@ void intel_ddi_pll_init(struct drm_device *dev)
>>
>>          hsw_shared_dplls_init(dev_priv);
>>
>> -       /* The LCPLL register should be turned on by the BIOS. For now let's
>> -        * just check its state and print errors in case something is wrong.
>> -        * Don't even try to turn it on.
>> -        */
>> -
>>          DRM_DEBUG_KMS("CDCLK running at %dKHz\n",
>>                        intel_ddi_get_cdclk_freq(dev_priv));
>>
>> -       if (val & LCPLL_CD_SOURCE_FCLK)
>> -               DRM_ERROR("CDCLK source is not LCPLL\n");
>> +       if (IS_SKYLAKE(dev)) {
>> +               if (!(I915_READ(LCPLL1_CTL) & LCPLL_PLL_ENABLE))
>> +                       DRM_ERROR("LCPLL1 is disabled\n");
>> +       } else {
>> +               /*
>> +                * The LCPLL register should be turned on by the BIOS. For now
>> +                * let's just check its state and print errors in case
>> +                * something is wrong.  Don't even try to turn it on.
>> +                */
>> +
>> +               if (val & LCPLL_CD_SOURCE_FCLK)
>> +                       DRM_ERROR("CDCLK source is not LCPLL\n");
>>
>> -       if (val & LCPLL_PLL_DISABLE)
>> -               DRM_ERROR("LCPLL is disabled\n");
>> +               if (val & LCPLL_PLL_DISABLE)
>> +                       DRM_ERROR("LCPLL is disabled\n");
>> +       }
>>   }
>>
>>   void intel_ddi_prepare_link_retrain(struct drm_encoder *encoder)
>> --
>> 1.8.3.1
>>
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>