Re: [PATCH 5/8] drm/i915: Use cdclk_state->voltage on SKL/KBL/CFL

Ville Syrjälä
2017-10-20T11:18:15Z

On Thu, Oct 19, 2017 at 04:47:08PM -0700, Rodrigo Vivi wrote:
> On Wed, Oct 18, 2017 at 08:48:22PM +0000, Ville Syrjala wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > Track the system agent voltage we request from pcode in the cdclk state
> > on SKL/KBL/CFL. Annoyingly we can't actually read out the current value since
> > there's no pcode command to do that, so we'll have to just assume that
> > it worked.
> >
> > Cc: Mika Kahola <mika.kahola@intel.com>
> > Cc: Manasi Navare <manasi.d.navare@intel.com>
> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> > drivers/gpu/drm/i915/intel_cdclk.c | 40 +++++++++++++++++++++++++++++++-------
> > 1 file changed, 33 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_cdclk.c b/drivers/gpu/drm/i915/intel_cdclk.c
> > index 7442e9443ffa..6f7b5abe6e3f 100644
> > --- a/drivers/gpu/drm/i915/intel_cdclk.c
> > +++ b/drivers/gpu/drm/i915/intel_cdclk.c
> > @@ -789,6 +789,24 @@ static int skl_calc_cdclk(int min_cdclk, int vco)
> > }
> > }
> >
> > +static u8 skl_calc_voltage(int cdclk)
> > +{
> > + switch (cdclk) {
> > + default:
> > + case 308571:
> > + case 337500:
> > + return 0;
> > + case 450000:
> > + case 432000:
> > + return 1;
> > + case 540000:
> > + return 2;
> > + case 617143:
> > + case 675000:
> > + return 3;
> > + }
> > +}
> > +
> > static void skl_dpll0_update(struct drm_i915_private *dev_priv,
> > struct intel_cdclk_state *cdclk_state)
> > {
> > @@ -839,7 +857,7 @@ static void skl_get_cdclk(struct drm_i915_private *dev_priv,
> > cdclk_state->cdclk = cdclk_state->ref;
> >
> > if (cdclk_state->vco == 0)
> > - return;
> > + goto out;
>
> why do we need this case?

Mainly just to make sure the entire state is consistent.

>
> >
> > cdctl = I915_READ(CDCLK_CTL);
> >
> > @@ -880,6 +898,13 @@ static void skl_get_cdclk(struct drm_i915_private *dev_priv,
> > break;
> > }
> > }
> > +
> > + out:
> > + /*
> > + * Can't read this out :( Let's assume it's
> > + * at least what the CDCLK frequency requires.
> > + */
> > + cdclk_state->voltage = skl_calc_voltage(cdclk_state->cdclk);
> > }
> >
> > /* convert from kHz to .1 fixpoint MHz with -1MHz offset */
> > @@ -964,7 +989,7 @@ static void skl_set_cdclk(struct drm_i915_private *dev_priv,
> > {
> > int cdclk = cdclk_state->cdclk;
> > int vco = cdclk_state->vco;
> > - u32 freq_select, pcu_ack;
> > + u32 freq_select;
> > int ret;
> >
> > mutex_lock(&dev_priv->pcu_lock);
> > @@ -988,21 +1013,17 @@ static void skl_set_cdclk(struct drm_i915_private *dev_priv,
> > case 308571:
> > case 337500:
> > freq_select = CDCLK_FREQ_337_308;
> > - pcu_ack = 0;
> > break;
> > case 450000:
> > case 432000:
> > freq_select = CDCLK_FREQ_450_432;
> > - pcu_ack = 1;
> > break;
> > case 540000:
> > freq_select = CDCLK_FREQ_540;
> > - pcu_ack = 2;
> > break;
> > case 617143:
> > case 675000:
> > freq_select = CDCLK_FREQ_675_617;
> > - pcu_ack = 3;
> > break;
> > }
> >
> > @@ -1018,7 +1039,8 @@ static void skl_set_cdclk(struct drm_i915_private *dev_priv,
> >
> > /* inform PCU of the change */
> > mutex_lock(&dev_priv->pcu_lock);
> > - sandybridge_pcode_write(dev_priv, SKL_PCODE_CDCLK_CONTROL, pcu_ack);
> > + sandybridge_pcode_write(dev_priv, SKL_PCODE_CDCLK_CONTROL,
> > + cdclk_state->voltage);
> > mutex_unlock(&dev_priv->pcu_lock);
> >
> > intel_update_cdclk(dev_priv);
> > @@ -1097,6 +1119,7 @@ void skl_init_cdclk(struct drm_i915_private *dev_priv)
> > if (cdclk_state.vco == 0)
> > cdclk_state.vco = 8100000;
> > cdclk_state.cdclk = skl_calc_cdclk(0, cdclk_state.vco);
> > + cdclk_state.voltage = skl_calc_voltage(cdclk_state.cdclk);
> >
> > skl_set_cdclk(dev_priv, &cdclk_state);
> > }
> > @@ -1114,6 +1137,7 @@ void skl_uninit_cdclk(struct drm_i915_private *dev_priv)
> >
> > cdclk_state.cdclk = cdclk_state.ref;
> > cdclk_state.vco = 0;
> > + cdclk_state.voltage = skl_calc_voltage(cdclk_state.cdclk);
> >
> > skl_set_cdclk(dev_priv, &cdclk_state);
> > }
> > @@ -1970,12 +1994,14 @@ static int skl_modeset_calc_cdclk(struct drm_atomic_state *state)
> >
> > intel_state->cdclk.logical.vco = vco;
> > intel_state->cdclk.logical.cdclk = cdclk;
> > + intel_state->cdclk.logical.voltage = skl_calc_voltage(cdclk);
> >
> > if (!intel_state->active_crtcs) {
> > cdclk = skl_calc_cdclk(0, vco);
> >
> > intel_state->cdclk.actual.vco = vco;
> > intel_state->cdclk.actual.cdclk = cdclk;
> > + intel_state->cdclk.actual.voltage = skl_calc_voltage(cdclk);
> > } else {
> > intel_state->cdclk.actual =
> > intel_state->cdclk.logical;
> > --
> > 2.13.6
> >

--
Ville Syrjälä
Intel OTC