Re: [PATCH 2/2] drm/i915: Fix chv cdclk support

["Mohan Marimuthu, Yogesh" <yogesh.mohan.marimuthu@intel.com>]

Reviewed-by: Yogesh Mohan Marimuthu <yogesh.mohan.marimuthu@intel.com>

Thank you,
Yogesh

On 3/9/2015 2:29 PM, Purushothaman, Vijay A wrote:
> On 3/2/2015 11:37 PM, ville.syrjala@linux.intel.com wrote:
>> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>>
>> The specs seem to be full of misinformation wrt. the Punit register
>> 0x36. Some versions still show the old VLV bit layout, some the new
>> layout, and all of them seem to tell us nonsense about the cdclk
>> value encoding.
>>
>> Testing on actual hardware has shown that we simply need to program
>> the desired CCK divider into the Punit register using the new layout of
>> the bits. Doing that, the status bit change to indicate the same value,
>> and the CCK 0x6b register also changes accordingly to indicate that CCK
>> is now using the new divider.
>>
>> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Reviewed-by: Vijay Purushothaman <vijay.a.purushothaman@linux.intel.com>
>
> Thanks,
> Vijay
>
>
>> ---
>>   drivers/gpu/drm/i915/intel_display.c | 23 +++++++----------------
>>   1 file changed, 7 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_display.c 
>> b/drivers/gpu/drm/i915/intel_display.c
>> index 94ff310..ca49b6f 100644
>> --- a/drivers/gpu/drm/i915/intel_display.c
>> +++ b/drivers/gpu/drm/i915/intel_display.c
>> @@ -4889,24 +4889,23 @@ static void cherryview_set_cdclk(struct 
>> drm_device *dev, int cdclk)
>>       WARN_ON(dev_priv->display.get_display_clock_speed(dev) != 
>> dev_priv->vlv_cdclk_freq);
>>         switch (cdclk) {
>> -    case 400000:
>> -        cmd = 3;
>> -        break;
>>       case 333333:
>>       case 320000:
>> -        cmd = 2;
>> -        break;
>>       case 266667:
>> -        cmd = 1;
>> -        break;
>>       case 200000:
>> -        cmd = 0;
>>           break;
>>       default:
>>           MISSING_CASE(cdclk);
>>           return;
>>       }
>>   +    /*
>> +     * Specs are full of misinformation, but testing on actual
>> +     * hardware has shown that we just need to write the desired
>> +     * CCK divider into the Punit register.
>> +     */
>> +    cmd = DIV_ROUND_CLOSEST(dev_priv->hpll_freq << 1, cdclk) - 1;
>> +
>>       mutex_lock(&dev_priv->rps.hw_lock);
>>       val = vlv_punit_read(dev_priv, PUNIT_REG_DSPFREQ);
>>       val &= ~DSPFREQGUAR_MASK_CHV;
>> @@ -4928,10 +4927,6 @@ static int valleyview_calc_cdclk(struct 
>> drm_i915_private *dev_priv,
>>       int freq_320 = (dev_priv->hpll_freq <<  1) % 320000 != 0 ? 
>> 333333 : 320000;
>>       int limit = IS_CHERRYVIEW(dev_priv) ? 95 : 90;
>>   -    /* FIXME: Punit isn't quite ready yet */
>> -    if (IS_CHERRYVIEW(dev_priv->dev))
>> -        return 400000;
>> -
>>       /*
>>        * Really only a few cases to deal with, as only 4 CDclks are 
>> supported:
>>        *   200MHz
>> @@ -5606,10 +5601,6 @@ static int 
>> valleyview_get_display_clock_speed(struct drm_device *dev)
>>       u32 val;
>>       int divider;
>>   -    /* FIXME: Punit isn't quite ready yet */
>> -    if (IS_CHERRYVIEW(dev))
>> -        return 400000;
>> -
>>       if (dev_priv->hpll_freq == 0)
>>           dev_priv->hpll_freq = valleyview_get_vco(dev_priv);
>
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