[Intel-gfx] [PATCH 05/20] drm/i915: Introduce AUX_CH_USBCn

[Ville Syrjälä]

On Thu, Oct 08, 2020 at 01:52:30AM -0700, Lucas De Marchi wrote:
> On Thu, Oct 08, 2020 at 11:40:28AM +0300, Ville Syrjälä wrote:
> >On Wed, Oct 07, 2020 at 03:51:11PM -0700, Lucas De Marchi wrote:
> >> On Tue, Oct 06, 2020 at 05:33:34PM +0300, Ville Syrjälä wrote:
> >> >From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> >> >
> >> >Just like with the DDIs tgl+ renamed the AUX CHs to reflect
> >> >the type of the DDI. Let's add the aliasing enum values for
> >> >the type-C AUX CHs.
> >> >
> >> >Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> >> >---
> >> > drivers/gpu/drm/i915/display/intel_display.h |  8 +++
> >> > drivers/gpu/drm/i915/display/intel_dp.c      | 53 ++++++++++++++++++--
> >> > 2 files changed, 58 insertions(+), 3 deletions(-)
> >> >
> >> >diff --git a/drivers/gpu/drm/i915/display/intel_display.h b/drivers/gpu/drm/i915/display/intel_display.h
> >> >index a39be3c9e0cf..cba876721ea0 100644
> >> >--- a/drivers/gpu/drm/i915/display/intel_display.h
> >> >+++ b/drivers/gpu/drm/i915/display/intel_display.h
> >> >@@ -290,6 +290,14 @@ enum aux_ch {
> >> > 	AUX_CH_G,
> >> > 	AUX_CH_H,
> >> > 	AUX_CH_I,
> >> >+
> >> >+	/* tgl+ */
> >> >+	AUX_CH_USBC1 = AUX_CH_D,
> >> >+	AUX_CH_USBC2,
> >> >+	AUX_CH_USBC3,
> >> >+	AUX_CH_USBC4,
> >> >+	AUX_CH_USBC5,
> >> >+	AUX_CH_USBC6,
> >> > };
> >> >
> >> > #define aux_ch_name(a) ((a) + 'A')
> >> >diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> >> >index 239016dcd544..a73c354c920e 100644
> >> >--- a/drivers/gpu/drm/i915/display/intel_dp.c
> >> >+++ b/drivers/gpu/drm/i915/display/intel_dp.c
> >> >@@ -1792,7 +1792,6 @@ static i915_reg_t skl_aux_ctl_reg(struct intel_dp *intel_dp)
> >> > 	case AUX_CH_D:
> >> > 	case AUX_CH_E:
> >> > 	case AUX_CH_F:
> >> >-	case AUX_CH_G:
> >> > 		return DP_AUX_CH_CTL(aux_ch);
> >> > 	default:
> >> > 		MISSING_CASE(aux_ch);
> >> >@@ -1813,7 +1812,52 @@ static i915_reg_t skl_aux_data_reg(struct intel_dp *intel_dp, int index)
> >> > 	case AUX_CH_D:
> >> > 	case AUX_CH_E:
> >> > 	case AUX_CH_F:
> >> >-	case AUX_CH_G:
> >> >+		return DP_AUX_CH_DATA(aux_ch, index);
> >> >+	default:
> >> >+		MISSING_CASE(aux_ch);
> >> >+		return DP_AUX_CH_DATA(AUX_CH_A, index);
> >> >+	}
> >> >+}
> >> >+
> >> >+static i915_reg_t tgl_aux_ctl_reg(struct intel_dp *intel_dp)
> >> >+{
> >> >+	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> >> >+	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> >> >+	enum aux_ch aux_ch = dig_port->aux_ch;
> >> >+
> >> >+	switch (aux_ch) {
> >> >+	case AUX_CH_A:
> >> >+	case AUX_CH_B:
> >> >+	case AUX_CH_C:
> >> >+	case AUX_CH_USBC1:
> >> >+	case AUX_CH_USBC2:
> >> >+	case AUX_CH_USBC3:
> >> >+	case AUX_CH_USBC4:
> >> >+	case AUX_CH_USBC5:
> >> >+	case AUX_CH_USBC6:
> >> >+		return DP_AUX_CH_CTL(aux_ch);
> >> >+	default:
> >> >+		MISSING_CASE(aux_ch);
> >> >+		return DP_AUX_CH_CTL(AUX_CH_A);
> >> >+	}
> >> >+}
> >> >+
> >> >+static i915_reg_t tgl_aux_data_reg(struct intel_dp *intel_dp, int index)
> >> >+{
> >> >+	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> >> >+	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> >> >+	enum aux_ch aux_ch = dig_port->aux_ch;
> >> >+
> >> >+	switch (aux_ch) {
> >> >+	case AUX_CH_A:
> >> >+	case AUX_CH_B:
> >> >+	case AUX_CH_C:
> >> >+	case AUX_CH_USBC1:
> >> >+	case AUX_CH_USBC2:
> >> >+	case AUX_CH_USBC3:
> >> >+	case AUX_CH_USBC4:
> >> >+	case AUX_CH_USBC5:
> >> >+	case AUX_CH_USBC6:
> >> > 		return DP_AUX_CH_DATA(aux_ch, index);
> >> > 	default:
> >> > 		MISSING_CASE(aux_ch);
> >> >@@ -1834,7 +1878,10 @@ intel_dp_aux_init(struct intel_dp *intel_dp)
> >> > 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> >> > 	struct intel_encoder *encoder = &dig_port->base;
> >> >
> >> >-	if (INTEL_GEN(dev_priv) >= 9) {
> >> >+	if (INTEL_GEN(dev_priv) >= 12) {
> >> >+		intel_dp->aux_ch_ctl_reg = tgl_aux_ctl_reg;
> >>
> >> why is this even a function pointer rather than just the reg? AFAICS it
> >> only depends on dig_port->aux_ch that is initialized in intel_ddi_init()
> >
> >Just for consistency with .aux_ch_data_reg() I guess. Can't remember
> >a more specific reason at least.
> 
> even that may be overkill since all the users just use index to
> do `+ index * 4`

The code used to do that but we got rid of it when the i915_reg
stuff was introduced to discourage people from doing hand rolled 
arithmetic on register offsets. I think the tradeoff has been
generally worth it because I can't remeber the last time someone
messed up the register offsets. Before type safety it was a
somewhat regular occurance.

-- 
Ville Syrjälä
Intel