[RFC 3/7] drm/i915/tgl: Enable DC3CO state in "DC Off" power well

[Anshuman Gupta <anshuman.gupta@intel.com>]

Add max_dc_state and tgl_set_target_dc_state() API
in order to enable DC3CO state with existing DC states.
max_dc_state will enable/disable the desired DC state in
DC_STATE_EN reg when "DC Off" power well gets disable/enable.

v2: commit log improvement.
v3: Used intel_wait_for_register to wait for DC3CO exit. [Imre]
    Used gen9_set_dc_state() to allow/disallow DC3CO. [Imre]
    Moved transcoder psr2 exit line enablement from tgl_allow_dc3co()
    to a appropriate place haswell_crtc_enable(). [Imre]
    Changed the DC3CO power well enabled call back logic as
    recommended in review comments. [Imre]
v4: Used wait_for_us() instead of intel_wait_for_reg(). [Imre (IRC)]
v5: using udelay() instead of waiting for DC3CO exit status.
v6: Fixed minor unwanted change.
v7: Removed DC3CO powerwell and POWER_DOMAIN_VIDEO.

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Animesh Manna <animesh.manna@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
---
 .../drm/i915/display/intel_display_power.c    | 106 ++++++++++++++----
 .../drm/i915/display/intel_display_power.h    |   2 +
 drivers/gpu/drm/i915/i915_drv.h               |   1 +
 3 files changed, 89 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
index 496fa1b53ffb..868197bb4860 100644
--- a/drivers/gpu/drm/i915/display/intel_display_power.c
+++ b/drivers/gpu/drm/i915/display/intel_display_power.c
@@ -772,6 +772,29 @@ static void gen9_set_dc_state(struct drm_i915_private *dev_priv, u32 state)
 	dev_priv->csr.dc_state = val & mask;
 }
 
+static void tgl_allow_dc3co(struct drm_i915_private *dev_priv)
+{
+	if (!dev_priv->psr.sink_psr2_support)
+		return;
+
+	if (dev_priv->csr.allowed_dc_mask & DC_STATE_EN_DC3CO)
+		gen9_set_dc_state(dev_priv, DC_STATE_EN_DC3CO);
+}
+
+static void tgl_disallow_dc3co(struct drm_i915_private *dev_priv)
+{
+	u32 val;
+
+	val = I915_READ(DC_STATE_EN);
+	val &= ~DC_STATE_DC3CO_STATUS;
+	I915_WRITE(DC_STATE_EN, val);
+	gen9_set_dc_state(dev_priv, DC_STATE_DISABLE);
+	/*
+	 * Delay of 200us DC3CO Exit time B.Spec 49196
+	 */
+	udelay(200);
+}
+
 static void bxt_enable_dc9(struct drm_i915_private *dev_priv)
 {
 	assert_can_enable_dc9(dev_priv);
@@ -939,7 +962,8 @@ static void bxt_verify_ddi_phy_power_wells(struct drm_i915_private *dev_priv)
 static bool gen9_dc_off_power_well_enabled(struct drm_i915_private *dev_priv,
 					   struct i915_power_well *power_well)
 {
-	return (I915_READ(DC_STATE_EN) & DC_STATE_EN_UPTO_DC5_DC6_MASK) == 0;
+	return ((I915_READ(DC_STATE_EN) & DC_STATE_EN_DC3CO) == 0 &&
+		(I915_READ(DC_STATE_EN) & DC_STATE_EN_UPTO_DC5_DC6_MASK) == 0);
 }
 
 static void gen9_assert_dbuf_enabled(struct drm_i915_private *dev_priv)
@@ -955,24 +979,32 @@ static void gen9_disable_dc_states(struct drm_i915_private *dev_priv)
 {
 	struct intel_cdclk_state cdclk_state = {};
 
-	gen9_set_dc_state(dev_priv, DC_STATE_DISABLE);
+	if (dev_priv->csr.max_dc_state & DC_STATE_EN_DC3CO) {
+		tgl_disallow_dc3co(dev_priv);
+	} else {
+		gen9_set_dc_state(dev_priv, DC_STATE_DISABLE);
 
-	dev_priv->display.get_cdclk(dev_priv, &cdclk_state);
-	/* Can't read out voltage_level so can't use intel_cdclk_changed() */
-	WARN_ON(intel_cdclk_needs_modeset(&dev_priv->cdclk.hw, &cdclk_state));
+		dev_priv->display.get_cdclk(dev_priv, &cdclk_state);
+		/*
+		 * Can't read out voltage_level so can't use
+		 * intel_cdclk_changed()
+		 */
+		WARN_ON(intel_cdclk_needs_modeset(&dev_priv->cdclk.hw,
+						  &cdclk_state));
 
-	gen9_assert_dbuf_enabled(dev_priv);
+		gen9_assert_dbuf_enabled(dev_priv);
 
-	if (IS_GEN9_LP(dev_priv))
-		bxt_verify_ddi_phy_power_wells(dev_priv);
+		if (IS_GEN9_LP(dev_priv))
+			bxt_verify_ddi_phy_power_wells(dev_priv);
 
-	if (INTEL_GEN(dev_priv) >= 11)
-		/*
-		 * DMC retains HW context only for port A, the other combo
-		 * PHY's HW context for port B is lost after DC transitions,
-		 * so we need to restore it manually.
-		 */
-		intel_combo_phy_init(dev_priv);
+		if (INTEL_GEN(dev_priv) >= 11)
+			/*
+			 * DMC retains HW context only for port A, the other
+			 * combo PHY's HW context for port B is lost after
+			 * DC transitions, so we need to restore it manually.
+			 */
+			intel_combo_phy_init(dev_priv);
+	}
 }
 
 static void gen9_dc_off_power_well_enable(struct drm_i915_private *dev_priv,
@@ -987,10 +1019,43 @@ static void gen9_dc_off_power_well_disable(struct drm_i915_private *dev_priv,
 	if (!dev_priv->csr.dmc_payload)
 		return;
 
-	if (dev_priv->csr.allowed_dc_mask & DC_STATE_EN_UPTO_DC6)
-		skl_enable_dc6(dev_priv);
-	else if (dev_priv->csr.allowed_dc_mask & DC_STATE_EN_UPTO_DC5)
-		gen9_enable_dc5(dev_priv);
+	if (dev_priv->csr.max_dc_state & DC_STATE_EN_DC3CO) {
+		tgl_allow_dc3co(dev_priv);
+	} else if (dev_priv->csr.max_dc_state & DC_STATE_EN_UPTO_DC5_DC6_MASK) {
+		if (dev_priv->csr.allowed_dc_mask & DC_STATE_EN_UPTO_DC6)
+			skl_enable_dc6(dev_priv);
+		else if (dev_priv->csr.allowed_dc_mask & DC_STATE_EN_UPTO_DC5)
+			gen9_enable_dc5(dev_priv);
+	}
+}
+
+void tgl_set_target_dc_state(struct drm_i915_private *dev_priv, u32 state)
+{
+	struct i915_power_well *power_well;
+	bool dc_off_enabled;
+	struct i915_power_domains *power_domains = &dev_priv->power_domains;
+
+	mutex_lock(&power_domains->lock);
+	power_well = lookup_power_well(dev_priv, TGL_DISP_DC_OFF);
+	dc_off_enabled = power_well->desc->ops->is_enabled(dev_priv,
+							   power_well);
+	if (state == dev_priv->csr.max_dc_state)
+		goto unlock;
+
+	if (!dc_off_enabled) {
+		/*
+		 * Need to disable the DC off power well to
+		 * effect target DC state.
+		 */
+		power_well->desc->ops->enable(dev_priv, power_well);
+		dev_priv->csr.max_dc_state = state;
+		power_well->desc->ops->disable(dev_priv, power_well);
+		goto unlock;
+	}
+		dev_priv->csr.max_dc_state = state;
+
+unlock:
+	mutex_unlock(&power_domains->lock);
 }
 
 static void i9xx_power_well_sync_hw_noop(struct drm_i915_private *dev_priv,
@@ -3610,7 +3675,7 @@ static const struct i915_power_well_desc tgl_power_wells[] = {
 		.name = "DC off",
 		.domains = TGL_DISPLAY_DC_OFF_POWER_DOMAINS,
 		.ops = &gen9_dc_off_power_well_ops,
-		.id = DISP_PW_ID_NONE,
+		.id = TGL_DISP_DC_OFF,
 	},
 	{
 		.name = "power well 2",
@@ -4039,6 +4104,7 @@ int intel_power_domains_init(struct drm_i915_private *dev_priv)
 	dev_priv->csr.allowed_dc_mask =
 		get_allowed_dc_mask(dev_priv, i915_modparams.enable_dc);
 
+	dev_priv->csr.max_dc_state = DC_STATE_EN_UPTO_DC5_DC6_MASK;
 	BUILD_BUG_ON(POWER_DOMAIN_NUM > 64);
 
 	mutex_init(&power_domains->lock);
diff --git a/drivers/gpu/drm/i915/display/intel_display_power.h b/drivers/gpu/drm/i915/display/intel_display_power.h
index 737b5def7fc6..1add626da458 100644
--- a/drivers/gpu/drm/i915/display/intel_display_power.h
+++ b/drivers/gpu/drm/i915/display/intel_display_power.h
@@ -100,6 +100,7 @@ enum i915_power_well_id {
 	SKL_DISP_PW_MISC_IO,
 	SKL_DISP_PW_1,
 	SKL_DISP_PW_2,
+	TGL_DISP_DC_OFF,
 };
 
 #define POWER_DOMAIN_PIPE(pipe) ((pipe) + POWER_DOMAIN_PIPE_A)
@@ -256,6 +257,7 @@ void intel_display_power_suspend_late(struct drm_i915_private *i915);
 void intel_display_power_resume_early(struct drm_i915_private *i915);
 void intel_display_power_suspend(struct drm_i915_private *i915);
 void intel_display_power_resume(struct drm_i915_private *i915);
+void tgl_set_target_dc_state(struct drm_i915_private *dev_priv, u32 state);
 
 const char *
 intel_display_power_domain_str(enum intel_display_power_domain domain);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index b42651a387d9..efe2eb121309 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -335,6 +335,7 @@ struct intel_csr {
 	i915_reg_t mmioaddr[20];
 	u32 mmiodata[20];
 	u32 dc_state;
+	u32 max_dc_state;
 	u32 allowed_dc_mask;
 	intel_wakeref_t wakeref;
 };
-- 
2.21.0

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