drm/i915/icl: apply Display WA #1178 to fix type C dongles

Display WA #1178 is meant to fix Aux channel voltage swing too low with
some type C dongles. It applies to external ports on combo phy. On
Icelake this is port A and B when those are not eDP.

v2: follow the spec to the letter: include Aux A and just check if it's
    not eDP instead of checking only for Aux B.

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181012215758.25342-1-lucas.demarchi@intel.com

drivers/gpu/drm/i915/i915_reg.h

@@ -8934,6 +8934,15 @@ enum skl_power_gate {
 #define   CNL_AUX_ANAOVRD1_ENABLE	(1 << 16)
 #define   CNL_AUX_ANAOVRD1_LDO_BYPASS	(1 << 23)
 
+#define _ICL_AUX_REG_IDX(pw_idx)	((pw_idx) - ICL_PW_CTL_IDX_AUX_A)
+#define _ICL_AUX_ANAOVRD1_A		0x162398
+#define _ICL_AUX_ANAOVRD1_B		0x6C398
+#define ICL_AUX_ANAOVRD1(pw_idx)	_MMIO(_PICK(_ICL_AUX_REG_IDX(pw_idx), \
+						    _ICL_AUX_ANAOVRD1_A, \
+						    _ICL_AUX_ANAOVRD1_B))
+#define   ICL_AUX_ANAOVRD1_LDO_BYPASS	(1 << 7)
+#define   ICL_AUX_ANAOVRD1_ENABLE	(1 << 0)
+
 /* HDCP Key Registers */
 #define HDCP_KEY_CONF			_MMIO(0x66c00)
 #define  HDCP_AKSV_SEND_TRIGGER		BIT(31)

drivers/gpu/drm/i915/intel_runtime_pm.c

@@ -436,6 +436,15 @@ icl_combo_phy_aux_power_well_enable(struct drm_i915_private *dev_priv,
 	I915_WRITE(ICL_PORT_CL_DW12(port), val | ICL_LANE_ENABLE_AUX);
 
 	hsw_wait_for_power_well_enable(dev_priv, power_well);
+
+	/* Display WA #1178: icl */
+	if (IS_ICELAKE(dev_priv) &&
+	    pw_idx >= ICL_PW_CTL_IDX_AUX_A && pw_idx <= ICL_PW_CTL_IDX_AUX_B &&
+	    !intel_bios_is_port_edp(dev_priv, port)) {
+		val = I915_READ(ICL_AUX_ANAOVRD1(pw_idx));
+		val |= ICL_AUX_ANAOVRD1_ENABLE | ICL_AUX_ANAOVRD1_LDO_BYPASS;
+		I915_WRITE(ICL_AUX_ANAOVRD1(pw_idx), val);
+	}
 }
 
 static void