Re: [PATCH v2 1/6] drm/i915/runtime_pm: Share code to enable/disable PCH reset handshake

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Fri, Sep 14, 2018 at 05:52:39PM +0300, Ville Syrjälä wrote:
> On Fri, Sep 14, 2018 at 07:18:44AM -0700, José Roberto de Souza wrote:
> > Instead of have the same code spread into 4 platforms lets share it.
> > BXT do not have a PCH so here also handling this case by unseting
> > RESET_PCH_HANDSHAKE_ENABLE.
> > 
> > v2(Rodrigo):
> > - renamed to intel_pch_reset_handshake()
> > - added comment about why BXT need the bit to be unset
> > 
> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_runtime_pm.c | 36 ++++++++++++-------------
> >  1 file changed, 17 insertions(+), 19 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> > index 9bebec389de1..1bcd0e51fca1 100644
> > --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> > @@ -3239,18 +3239,29 @@ static void icl_mbus_init(struct drm_i915_private *dev_priv)
> >  	I915_WRITE(MBUS_ABOX_CTL, val);
> >  }
> >  
> > +static void intel_pch_reset_handshake(struct drm_i915_private *dev_priv)
> > +{
> > +	u32 val = I915_READ(HSW_NDE_RSTWRN_OPT);
> > +
> > +	/* BXT don't have PCH and it requires that this bit is always unset */
> > +	if (HAS_PCH_SPLIT(dev_priv))
> 
> Still would prefer 'bool enable' etc. rather than this magic inside.

I agree. So we could keep the original BXT comment where it is...

> 
> > +		val |= RESET_PCH_HANDSHAKE_ENABLE;
> > +	else
> > +		val &= ~RESET_PCH_HANDSHAKE_ENABLE;
> > +
> > +	I915_WRITE(HSW_NDE_RSTWRN_OPT, val);
> > +}
> > +
> >  static void skl_display_core_init(struct drm_i915_private *dev_priv,
> >  				   bool resume)
> >  {
> >  	struct i915_power_domains *power_domains = &dev_priv->power_domains;
> >  	struct i915_power_well *well;
> > -	uint32_t val;
> >  
> >  	gen9_set_dc_state(dev_priv, DC_STATE_DISABLE);
> >  
> >  	/* enable PCH reset handshake */
> > -	val = I915_READ(HSW_NDE_RSTWRN_OPT);
> > -	I915_WRITE(HSW_NDE_RSTWRN_OPT, val | RESET_PCH_HANDSHAKE_ENABLE);
> > +	intel_pch_reset_handshake(dev_priv);
> >  
> >  	/* enable PG1 and Misc I/O */
> >  	mutex_lock(&power_domains->lock);
> > @@ -3306,19 +3317,10 @@ void bxt_display_core_init(struct drm_i915_private *dev_priv,
> >  {
> >  	struct i915_power_domains *power_domains = &dev_priv->power_domains;
> >  	struct i915_power_well *well;
> > -	uint32_t val;
> >  
> >  	gen9_set_dc_state(dev_priv, DC_STATE_DISABLE);
> >  
> > -	/*
> > -	 * NDE_RSTWRN_OPT RST PCH Handshake En must always be 0b on BXT
> > -	 * or else the reset will hang because there is no PCH to respond.
> > -	 * Move the handshake programming to initialization sequence.
> > -	 * Previously was left up to BIOS.
> > -	 */
> > -	val = I915_READ(HSW_NDE_RSTWRN_OPT);
> > -	val &= ~RESET_PCH_HANDSHAKE_ENABLE;
> > -	I915_WRITE(HSW_NDE_RSTWRN_OPT, val);
> > +	intel_pch_reset_handshake(dev_priv);
> >  
> >  	/* Enable PG1 */
> >  	mutex_lock(&power_domains->lock);
> > @@ -3439,9 +3441,7 @@ static void cnl_display_core_init(struct drm_i915_private *dev_priv, bool resume
> >  	gen9_set_dc_state(dev_priv, DC_STATE_DISABLE);
> >  
> >  	/* 1. Enable PCH Reset Handshake */
> > -	val = I915_READ(HSW_NDE_RSTWRN_OPT);
> > -	val |= RESET_PCH_HANDSHAKE_ENABLE;
> > -	I915_WRITE(HSW_NDE_RSTWRN_OPT, val);
> > +	intel_pch_reset_handshake(dev_priv);
> >  
> >  	/* 2. Enable Comp */
> >  	val = I915_READ(CHICKEN_MISC_2);
> > @@ -3524,9 +3524,7 @@ static void icl_display_core_init(struct drm_i915_private *dev_priv,
> >  	gen9_set_dc_state(dev_priv, DC_STATE_DISABLE);
> >  
> >  	/* 1. Enable PCH reset handshake. */
> > -	val = I915_READ(HSW_NDE_RSTWRN_OPT);
> > -	val |= RESET_PCH_HANDSHAKE_ENABLE;
> > -	I915_WRITE(HSW_NDE_RSTWRN_OPT, val);
> > +	intel_pch_reset_handshake(dev_priv);
> >  
> >  	for (port = PORT_A; port <= PORT_B; port++) {
> >  		/* 2. Enable DDI combo PHY comp. */
> > -- 
> > 2.19.0
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Ville Syrjälä
> Intel
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