Re: [PATCH v2] drm/i915/display: Implement new combo phy initialization step

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On Mon, Jul 06, 2020 at 04:10:15PM -0700, Souza, Jose wrote:
> On Mon, 2020-07-06 at 16:08 -0700, Matt Roper wrote:
> > On Wed, Jun 24, 2020 at 12:32:49PM -0700, José Roberto de Souza wrote:
> > > This is new step that was recently added to the combo phy
> > > initialization.
> > > 
> > > v2:
> > > - using intel_de_rmw()
> > 
> > Actually, I'm not sure whether this is valid; I believe we always have
> > to read from a lane register and can only write to the group registers:
> > 
> >         "Reads using a port group address usually cannot return correct
> >         data. For read/modify/write to a group, the read should be to
> >         one of the lane addresses, then the write to the group address."
> 
> Yep, v3 is doing the right thing: https://patchwork.freedesktop.org/series/78796/

Ah, I overlooked that, thanks.  I think my other comments below may
still apply to v3 though.


Matt

> 
> > 
> > > BSpec: 49291
> > > Cc: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
> > > Signed-off-by: José Roberto de Souza <jose.souza@xxxxxxxxx>
> > > ---
> > >  .../gpu/drm/i915/display/intel_combo_phy.c    | 23 +++++++++++++++++++
> > >  drivers/gpu/drm/i915/i915_reg.h               |  7 ++++++
> > >  2 files changed, 30 insertions(+)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/display/intel_combo_phy.c b/drivers/gpu/drm/i915/display/intel_combo_phy.c
> > > index 77b04bb3ec62..115069833348 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_combo_phy.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_combo_phy.c
> > > @@ -264,6 +264,18 @@ static bool icl_combo_phy_verify_state(struct drm_i915_private *dev_priv,
> > >  	if (!icl_combo_phy_enabled(dev_priv, phy))
> > >  		return false;
> > >  
> > > +	if (INTEL_GEN(dev_priv) >= 12) {
> > > +		ret &= check_phy_reg(dev_priv, phy, ICL_PORT_TX_DW8_GRP(phy),
> > > +				     ICL_PORT_TX_DW8_ODCC_CLK_SEL |
> > > +				     ICL_PORT_TX_DW8_ODCC_CLK_DIV_SEL_MASK,
> > > +				     ICL_PORT_TX_DW8_ODCC_CLK_SEL |
> > > +				     ICL_PORT_TX_DW8_ODCC_CLK_DIV_SEL_DIV2);
> > 
> > If I'm reading the bspec correctly, it looks like both 00 and 01
> > represent div2 for this register.  So maybe rather than looking for 01
> > exactly here we should just check that bit 30 is off?
> > 
> > 
> > > +
> > > +		ret &= check_phy_reg(dev_priv, phy, ICL_PORT_PCS_DW1_GRP(phy),
> > > +				     DCC_MODE_SELECT_MASK,
> > > +				     DCC_MODE_SELECT_CONTINUOSLY);
> > > +	}
> > > +
> > >  	ret = cnl_verify_procmon_ref_values(dev_priv, phy);
> > >  
> > >  	if (phy_is_master(dev_priv, phy)) {
> > > @@ -375,6 +387,17 @@ static void icl_combo_phys_init(struct drm_i915_private *dev_priv)
> > >  		intel_de_write(dev_priv, ICL_PHY_MISC(phy), val);
> > >  
> > >  skip_phy_misc:
> > > +		if (INTEL_GEN(dev_priv) >= 12) {
> > 
> > We may want to keep an eye on this part of the bspec; there seems to be
> > something a bit off with the bspec tagging of this block and I'm not
> > 100% sure it was actually intended to apply to RKL too or not.
> > 
> > It seems like the bspec has these steps as the very first thing, even
> > before the "check whether the PHY is already initialized" step.
> > But since we're checking that the bits are set the way we want in the
> > verify function too, I don't think the ordering should matter.
> > 
> > > +			intel_de_rmw(dev_priv, ICL_PORT_TX_DW8_GRP(phy),
> > > +				     ICL_PORT_TX_DW8_ODCC_CLK_DIV_SEL_MASK,
> > > +				     ICL_PORT_TX_DW8_ODCC_CLK_SEL |
> > > +				     ICL_PORT_TX_DW8_ODCC_CLK_DIV_SEL_DIV2);
> > 
> > As noted above, maybe we should just clear bit 30 and leave bit 29 set
> > however it already was?
> > 
> > 
> > Matt
> > 
> > > +
> > > +			intel_de_rmw(dev_priv, ICL_PORT_PCS_DW1_GRP(phy),
> > > +				     DCC_MODE_SELECT_MASK,
> > > +				     DCC_MODE_SELECT_CONTINUOSLY);
> > > +		}
> > > +
> > >  		cnl_set_procmon_ref_values(dev_priv, phy);
> > >  
> > >  		if (phy_is_master(dev_priv, phy)) {
> > > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > > index f09120cac89a..5469c9029f6d 100644
> > > --- a/drivers/gpu/drm/i915/i915_reg.h
> > > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > > @@ -1974,6 +1974,8 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
> > >  #define ICL_PORT_PCS_DW1_AUX(phy)	_MMIO(_ICL_PORT_PCS_DW_AUX(1, phy))
> > >  #define ICL_PORT_PCS_DW1_GRP(phy)	_MMIO(_ICL_PORT_PCS_DW_GRP(1, phy))
> > >  #define ICL_PORT_PCS_DW1_LN0(phy)	_MMIO(_ICL_PORT_PCS_DW_LN(1, 0, phy))
> > > +#define   DCC_MODE_SELECT_MASK		(0x3 << 20)
> > > +#define   DCC_MODE_SELECT_CONTINUOSLY	(0x3 << 20)
> > >  #define   COMMON_KEEPER_EN		(1 << 26)
> > >  #define   LATENCY_OPTIM_MASK		(0x3 << 2)
> > >  #define   LATENCY_OPTIM_VAL(x)		((x) << 2)
> > > @@ -2072,6 +2074,11 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
> > >  #define   N_SCALAR(x)			((x) << 24)
> > >  #define   N_SCALAR_MASK			(0x7F << 24)
> > >  
> > > +#define ICL_PORT_TX_DW8_GRP(phy)		_MMIO(_ICL_PORT_TX_DW_GRP(8, phy))
> > > +#define ICL_PORT_TX_DW8_ODCC_CLK_SEL		REG_BIT(31)
> > > +#define ICL_PORT_TX_DW8_ODCC_CLK_DIV_SEL_MASK	REG_GENMASK(30, 29)
> > > +#define ICL_PORT_TX_DW8_ODCC_CLK_DIV_SEL_DIV2	REG_FIELD_PREP(ICL_PORT_TX_DW8_ODCC_CLK_DIV_SEL_MASK, 0x1)
> > > +
> > >  #define _ICL_DPHY_CHKN_REG			0x194
> > >  #define ICL_DPHY_CHKN(port)			_MMIO(_ICL_COMBOPHY(port) + _ICL_DPHY_CHKN_REG)
> > >  #define   ICL_DPHY_CHKN_AFE_OVER_PPI_STRAP	REG_BIT(7)
> > > -- 
> > > 2.27.0
> > > 
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation
(916) 356-2795
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