[PATCH 06/17] drm/i915/ddi: Simplify the port disabling via DDI_BUF_CTL

[Imre Deak <imre.deak@intel.com>]

A port can be disabled only via a modeset (or during HW state
sanitization) when the port is enabled. Thus it's not required to check
the port's enabled state before disabling it. In any case if the port
happened to be disabled, the following disabling would be just a nop and
waiting for the buffer's idle state should succeed. Simplify the
disabling sequence accordingly.

Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 drivers/gpu/drm/i915/display/intel_ddi.c | 23 +++++------------------
 1 file changed, 5 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index 3138dc4034797..24c56d2aa5f31 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -3062,17 +3062,12 @@ static void mtl_disable_ddi_buf(struct intel_encoder *encoder,
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	enum port port = encoder->port;
-	u32 val;
 
 	/* 3.b Clear DDI_CTL_DE Enable to 0. */
-	val = intel_de_read(dev_priv, DDI_BUF_CTL(port));
-	if (val & DDI_BUF_CTL_ENABLE) {
-		val &= ~DDI_BUF_CTL_ENABLE;
-		intel_de_write(dev_priv, DDI_BUF_CTL(port), val);
+	intel_de_rmw(dev_priv, DDI_BUF_CTL(port), DDI_BUF_CTL_ENABLE, 0);
 
-		/* 3.c Poll for PORT_BUF_CTL Idle Status == 1, timeout after 100us */
-		mtl_wait_ddi_buf_idle(dev_priv, port);
-	}
+	/* 3.c Poll for PORT_BUF_CTL Idle Status == 1, timeout after 100us */
+	mtl_wait_ddi_buf_idle(dev_priv, port);
 
 	/* 3.d Disable D2D Link */
 	mtl_ddi_disable_d2d_link(encoder);
@@ -3089,15 +3084,8 @@ static void disable_ddi_buf(struct intel_encoder *encoder,
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	enum port port = encoder->port;
-	bool wait = false;
-	u32 val;
 
-	val = intel_de_read(dev_priv, DDI_BUF_CTL(port));
-	if (val & DDI_BUF_CTL_ENABLE) {
-		val &= ~DDI_BUF_CTL_ENABLE;
-		intel_de_write(dev_priv, DDI_BUF_CTL(port), val);
-		wait = true;
-	}
+	intel_de_rmw(dev_priv, DDI_BUF_CTL(port), DDI_BUF_CTL_ENABLE, 0);
 
 	if (intel_crtc_has_dp_encoder(crtc_state))
 		intel_de_rmw(dev_priv, dp_tp_ctl_reg(encoder, crtc_state),
@@ -3105,8 +3093,7 @@ static void disable_ddi_buf(struct intel_encoder *encoder,
 
 	intel_ddi_disable_fec(encoder, crtc_state);
 
-	if (wait)
-		intel_wait_ddi_buf_idle(dev_priv, port);
+	intel_wait_ddi_buf_idle(dev_priv, port);
 }
 
 static void intel_disable_ddi_buf(struct intel_encoder *encoder,
-- 
2.44.2