Re: [PATCH v4 1/5] drm/i915/gen11: Start distinguishing 'phy' from 'port'

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, Jul 04, 2019 at 07:54:26AM -0700, Lucas De Marchi wrote:
> On Thu, Jul 04, 2019 at 12:18:11PM +0300, Ville Syrjälä wrote:
> >On Wed, Jul 03, 2019 at 04:37:32PM -0700, Matt Roper wrote:
> >> Our past DDI-based Intel platforms have had a fixed DDI<->PHY mapping.
> >> Because of this, both the bspec documentation and our i915 code has used
> >> the term "port" when talking about either DDI's or PHY's; it was always
> >> easy to tell what terms like "Port A" were referring to from the
> >> context.
> >>
> >> Unfortunately this is starting to break down now that EHL allows PHY-A
> >> to be driven by either DDI-A or DDI-D.  Is a setup with DDI-D driving
> >> PHY-A considered "Port A" or "Port D?"  The answer depends on which
> >> register we're working with, and even the bspec doesn't do a great job
> >> of clarifying this.
> >>
> >> Let's try to be more explicit about whether we're talking about the DDI
> >> or the PHY on gen11+ by using 'port' to refer to the DDI and creating a
> >> new 'enum phy' namespace to refer to the PHY in use.
> >>
> >> This patch just adds the new PHY namespace, new phy-based versions of
> >> intel_port_is_*(), and a helper to convert a port to a PHY.
> >> Transitioning various areas of the code over to using the PHY namespace
> >> will be done in subsequent patches to make review easier.  We'll remove
> >> the intel_port_is_*() functions at the end of the series when we
> >> transition all callers over to using the PHY-based versions.
> >>
> >> v2:
> >>  - Convert a few more 'port' uses to 'phy.' (Sparse)
> >>
> >> v3:
> >>  - Switch DDI_CLK_SEL() back to 'port.' (Jose)
> >>  - Add a code comment clarifying why DPCLKA_CFGCR0_ICL needs to use PHY
> >>    for its bit definitions, even though the register description is
> >>    given in terms of DDI.
> >>  - To avoid confusion, switch CNL's DPCLKA_CFGCR0 defines back to using
> >>    port and create separate ICL+ definitions that work in terms of PHY.
> >>
> >> v4:
> >>  - Rebase and resolve conflicts with Imre's TC series.
> >>  - This patch now just adds the namespace and a few convenience
> >>    functions; the important changes are now split out into separate
> >>    patches to make review easier.
> >>
> >> Suggested-by: Ville Syrjala <ville.syrjala@linux.intel.com>
> >> Cc: José Roberto de Souza <jose.souza@intel.com>
> >> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> >> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >> Cc: Imre Deak <imre.deak@intel.com>
> >> Cc: Jani Nikula <jani.nikula@intel.com>
> >> Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
> >> ---
> >>  drivers/gpu/drm/i915/display/intel_display.c | 32 +++++++++++++++++++-
> >>  drivers/gpu/drm/i915/display/intel_display.h | 16 ++++++++++
> >>  drivers/gpu/drm/i915/intel_drv.h             |  2 ++
> >>  3 files changed, 49 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> >> index 919f5ac844c8..4a85abef93e7 100644
> >> --- a/drivers/gpu/drm/i915/display/intel_display.c
> >> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> >> @@ -6663,6 +6663,20 @@ bool intel_port_is_combophy(struct drm_i915_private *dev_priv, enum port port)
> >>  	return false;
> >>  }
> >>
> >> +bool intel_phy_is_combo(struct drm_i915_private *dev_priv, enum phy phy)
> >> +{
> >> +	if (phy == PHY_NONE)
> >> +		return false;
> >> +
> >> +	if (IS_ELKHARTLAKE(dev_priv))
> >> +		return phy <= PHY_C;
> >> +
> >> +	if (INTEL_GEN(dev_priv) >= 11)
> >> +		return phy <= PHY_B;
> >> +
> >> +	return false;
> >> +}
> >> +
> >>  bool intel_port_is_tc(struct drm_i915_private *dev_priv, enum port port)
> >>  {
> >>  	if (INTEL_GEN(dev_priv) >= 11 && !IS_ELKHARTLAKE(dev_priv))
> >> @@ -6671,9 +6685,25 @@ bool intel_port_is_tc(struct drm_i915_private *dev_priv, enum port port)
> >>  	return false;
> >>  }
> >>
> >> +bool intel_phy_is_tc(struct drm_i915_private *dev_priv, enum phy phy)
> >> +{
> >> +	if (INTEL_GEN(dev_priv) >= 11 && !IS_ELKHARTLAKE(dev_priv))
> >> +		return phy >= PHY_C && phy <= PHY_F;
> >> +
> >> +	return false;
> >> +}
> >> +
> >> +enum phy intel_port_to_phy(struct drm_i915_private *i915, enum port port)
> >> +{
> >> +	if (IS_ELKHARTLAKE(i915) && port == PORT_D)
> >> +		return PHY_A;
> >> +
> >> +	return (enum phy)port;
> >> +}
> >> +
> >>  enum tc_port intel_port_to_tc(struct drm_i915_private *dev_priv, enum port port)
> >>  {
> >> -	if (!intel_port_is_tc(dev_priv, port))
> >> +	if (!intel_phy_is_tc(dev_priv, intel_port_to_phy(dev_priv, port)))
> >>  		return PORT_TC_NONE;
> >>
> >>  	return port - PORT_C;
> >> diff --git a/drivers/gpu/drm/i915/display/intel_display.h b/drivers/gpu/drm/i915/display/intel_display.h
> >> index d296556ed82e..d53285fb883f 100644
> >> --- a/drivers/gpu/drm/i915/display/intel_display.h
> >> +++ b/drivers/gpu/drm/i915/display/intel_display.h
> >> @@ -228,6 +228,21 @@ struct intel_link_m_n {
> >>  	u32 link_n;
> >>  };
> >>
> >> +enum phy {
> >> +	PHY_NONE = -1,
> >> +
> >> +	PHY_A = 0,
> >> +	PHY_B,
> >> +	PHY_C,
> >> +	PHY_D,
> >> +	PHY_E,
> >> +	PHY_F,
> >> +
> >> +	I915_MAX_PHYS
> >> +};
> >
> >I was pondering if we could eventually do something like:
> >
> >enum phy {
> >	PHY_COMBO_A = 0,
> >	PHY_COMBO_B,
> >	...
> >
> >	PHY_TC_1,
> >	PHY_TC_2,
> >	...
> >};
> >
> >and probably also add encoder->phy so we can contain
> >that port<->phy mapping logic in the encoder init.
> >I think that should work more or less fine since I
> >don't think PHY_TC_1 needs to have any specific value.
> 
> that's not true. All TC registers are based off the TC phy number.

That's just a trivial (x)-TC1, so I stand by what I said.

> Hence all the conversion we do port_to_tc()... I'd like to remove that
> in future and just stuff the phy index in intel_digital_port, as we
> already do for other tc_phy_* fields (we could add a union there so each
> phy adds its own fields).
> 
> And I'd rather not do the single phy namespace - it doesn't
> play well with TGL and the combo/tc.

I think it would work just fine for that. A single namespace would allow
us to remove all the crazy port->PHY type mapping we have going on
currently. Probably the best alternative would be separate namespaces
for each type with a new enum to identify the type.

> 
> Lucas De Marchi
> 
> >
> >Unfortunaltey I don't have a great idea how to do the
> >same for the DDIs since there the number of combo DDIs
> >changes but we still need the PORT_TC1 (assuming we had
> >one) to be DDI_<last combo DDI> + 1. One random silly
> >idea was to decouple the enum port from the register
> >definitions by having just some kind of
> >encoder->port_index for those. But that doesn't feel
> >entirely great either.
> >
> >Anyways, something to think about in the future perhaps.
> >
> >Patch is
> >Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> >> +
> >> +#define phy_name(a) ((a) + 'A')
> >> +
> >>  #define for_each_pipe(__dev_priv, __p) \
> >>  	for ((__p) = 0; (__p) < INTEL_INFO(__dev_priv)->num_pipes; (__p)++)
> >>
> >> @@ -356,5 +371,6 @@ void lpt_disable_clkout_dp(struct drm_i915_private *dev_priv);
> >>  u32 intel_plane_fb_max_stride(struct drm_i915_private *dev_priv,
> >>  			      u32 pixel_format, u64 modifier);
> >>  bool intel_plane_can_remap(const struct intel_plane_state *plane_state);
> >> +enum phy intel_port_to_phy(struct drm_i915_private *i915, enum port port);
> >>
> >>  #endif
> >> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> >> index 24c63ed45c6f..815c26c0b98c 100644
> >> --- a/drivers/gpu/drm/i915/intel_drv.h
> >> +++ b/drivers/gpu/drm/i915/intel_drv.h
> >> @@ -1493,7 +1493,9 @@ void intel_encoder_destroy(struct drm_encoder *encoder);
> >>  struct drm_display_mode *
> >>  intel_encoder_current_mode(struct intel_encoder *encoder);
> >>  bool intel_port_is_combophy(struct drm_i915_private *dev_priv, enum port port);
> >> +bool intel_phy_is_combo(struct drm_i915_private *dev_priv, enum phy phy);
> >>  bool intel_port_is_tc(struct drm_i915_private *dev_priv, enum port port);
> >> +bool intel_phy_is_tc(struct drm_i915_private *dev_priv, enum phy phy);
> >>  enum tc_port intel_port_to_tc(struct drm_i915_private *dev_priv,
> >>  			      enum port port);
> >>  int intel_get_pipe_from_crtc_id_ioctl(struct drm_device *dev, void *data,
> >> --
> >> 2.17.2
> >
> >-- 
> >Ville Syrjälä
> >Intel

-- 
Ville Syrjälä
Intel
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx