drm/i915/psr: New power domain for AUX IO.

PSR on CNL requires AUX IO wells to be kept on and the existing AUX domain
for AUX-A enables DC_OFF well too. This is not required, so add a new
AUX_IO_A domain for AUX-A to allow DC states to remain enabled. Other AUX
channels re-use the existing AUX domains.

v4: Reword comment (Rodrigo and Ville)
    Rename _get and _put functions to include aux_io substring(Rodrigo)
    Remove unnecessary diff that got included.
v3: Extract aux domain selection into a function (Ville)
v2: Add AUX IO domain only for AUX-A
    Rebased on top of Ville's AUX series.

Cc: Imre Deak <imre.deak@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Suggested-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180223221520.18464-1-dhinakaran.pandiyan@intel.com

drivers/gpu/drm/i915/intel_display.h

@@ -186,6 +186,7 @@ enum intel_display_power_domain {
 	POWER_DOMAIN_AUX_C,
 	POWER_DOMAIN_AUX_D,
 	POWER_DOMAIN_AUX_F,
+	POWER_DOMAIN_AUX_IO_A,
 	POWER_DOMAIN_GMBUS,
 	POWER_DOMAIN_MODESET,
 	POWER_DOMAIN_GT_IRQ,

drivers/gpu/drm/i915/intel_psr.c

@@ -56,6 +56,43 @@
 #include "intel_drv.h"
 #include "i915_drv.h"
 
+static inline enum intel_display_power_domain
+psr_aux_domain(struct intel_dp *intel_dp)
+{
+	/* CNL HW requires corresponding AUX IOs to be powered up for PSR.
+	 * However, for non-A AUX ports the corresponding non-EDP transcoders
+	 * would have already enabled power well 2 and DC_OFF. This means we can
+	 * acquire a wider POWER_DOMAIN_AUX_{B,C,D,F} reference instead of a
+	 * specific AUX_IO reference without powering up any extra wells.
+	 * Note that PSR is enabled only on Port A even though this function
+	 * returns the correct domain for other ports too.
+	 */
+	return intel_dp->aux_ch == AUX_CH_A ? POWER_DOMAIN_AUX_IO_A :
+					      intel_dp->aux_power_domain;
+}
+
+static void psr_aux_io_power_get(struct intel_dp *intel_dp)
+{
+	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
+	struct drm_i915_private *dev_priv = to_i915(intel_dig_port->base.base.dev);
+
+	if (INTEL_GEN(dev_priv) < 10)
+		return;
+
+	intel_display_power_get(dev_priv, psr_aux_domain(intel_dp));
+}
+
+static void psr_aux_io_power_put(struct intel_dp *intel_dp)
+{
+	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
+	struct drm_i915_private *dev_priv = to_i915(intel_dig_port->base.base.dev);
+
+	if (INTEL_GEN(dev_priv) < 10)
+		return;
+
+	intel_display_power_put(dev_priv, psr_aux_domain(intel_dp));
+}
+
 static bool vlv_is_psr_active_on_pipe(struct drm_device *dev, int pipe)
 {
 	struct drm_i915_private *dev_priv = to_i915(dev);
@@ -459,6 +496,8 @@ static void hsw_psr_enable_source(struct intel_dp *intel_dp,
 	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
 	u32 chicken;
 
+	psr_aux_io_power_get(intel_dp);
+
 	if (dev_priv->psr.psr2_support) {
 		chicken = PSR2_VSC_ENABLE_PROG_HEADER;
 		if (dev_priv->psr.y_cord_support)
@@ -617,6 +656,8 @@ static void hsw_psr_disable(struct intel_dp *intel_dp,
 		else
 			WARN_ON(I915_READ(EDP_PSR_CTL) & EDP_PSR_ENABLE);
 	}
+
+	psr_aux_io_power_put(intel_dp);
 }
 
 /**

drivers/gpu/drm/i915/intel_runtime_pm.c

@@ -130,6 +130,8 @@ intel_display_power_domain_str(enum intel_display_power_domain domain)
 		return "AUX_D";
 	case POWER_DOMAIN_AUX_F:
 		return "AUX_F";
+	case POWER_DOMAIN_AUX_IO_A:
+		return "AUX_IO_A";
 	case POWER_DOMAIN_GMBUS:
 		return "GMBUS";
 	case POWER_DOMAIN_INIT:
@@ -1853,6 +1855,7 @@ void intel_display_power_put(struct drm_i915_private *dev_priv,
 	BIT_ULL(POWER_DOMAIN_INIT))
 #define CNL_DISPLAY_AUX_A_POWER_DOMAINS (		\
 	BIT_ULL(POWER_DOMAIN_AUX_A) |			\
+	BIT_ULL(POWER_DOMAIN_AUX_IO_A) |		\
 	BIT_ULL(POWER_DOMAIN_INIT))
 #define CNL_DISPLAY_AUX_B_POWER_DOMAINS (		\
 	BIT_ULL(POWER_DOMAIN_AUX_B) |			\