drm/i915/xe2lpd: Move D2D enable/disable

Bits to enable/disable and check state for D2D moved from
XELPDP_PORT_BUF_CTL1 to DDI_BUF_CTL (now named DDI_CTL_DE in the spec).
Make the functions mtl_ddi_disable_d2d() and mtl_ddi_enable_d2d generic
to work with multiple reg location and bitfield layout.

v2: Set/Clear XE2LPD_DDI_BUF_D2D_LINK_ENABLE in saved_port_bits when
    enabling/disabling D2D so DDI_BUF_CTL is correctly programmed in
    other places without overriding these bits (Clint)
v3: Leave saved_port_bits alone as those bits are not meant to be
    modified outside of the port initialization. Rather propagate the
    additional bit in DDI_BUF_CTL to be set when that register is
    written again after D2D is enabled.

Cc: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240126224638.4132016-2-lucas.demarchi@intel.com

drivers/gpu/drm/i915/display/intel_ddi.c

@@ -2429,13 +2429,22 @@ mtl_ddi_enable_d2d(struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	enum port port = encoder->port;
+	i915_reg_t reg;
+	u32 set_bits, wait_bits;
 
-	intel_de_rmw(dev_priv, XELPDP_PORT_BUF_CTL1(port), 0,
-		     XELPDP_PORT_BUF_D2D_LINK_ENABLE);
+	if (DISPLAY_VER(dev_priv) >= 20) {
+		reg = DDI_BUF_CTL(port);
+		set_bits = XE2LPD_DDI_BUF_D2D_LINK_ENABLE;
+		wait_bits = XE2LPD_DDI_BUF_D2D_LINK_STATE;
+	} else {
+		reg = XELPDP_PORT_BUF_CTL1(port);
+		set_bits = XELPDP_PORT_BUF_D2D_LINK_ENABLE;
+		wait_bits = XELPDP_PORT_BUF_D2D_LINK_STATE;
+	}
 
-	if (wait_for_us((intel_de_read(dev_priv, XELPDP_PORT_BUF_CTL1(port)) &
-			 XELPDP_PORT_BUF_D2D_LINK_STATE), 100)) {
-		drm_err(&dev_priv->drm, "Timeout waiting for D2D Link enable for PORT_BUF_CTL %c\n",
+	intel_de_rmw(dev_priv, reg, 0, set_bits);
+	if (wait_for_us(intel_de_read(dev_priv, reg) & wait_bits, 100)) {
+		drm_err(&dev_priv->drm, "Timeout waiting for D2D Link enable for DDI/PORT_BUF_CTL %c\n",
 			port_name(port));
 	}
 }
@@ -2898,13 +2907,22 @@ mtl_ddi_disable_d2d_link(struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	enum port port = encoder->port;
+	i915_reg_t reg;
+	u32 clr_bits, wait_bits;
 
-	intel_de_rmw(dev_priv, XELPDP_PORT_BUF_CTL1(port),
-		     XELPDP_PORT_BUF_D2D_LINK_ENABLE, 0);
+	if (DISPLAY_VER(dev_priv) >= 20) {
+		reg = DDI_BUF_CTL(port);
+		clr_bits = XE2LPD_DDI_BUF_D2D_LINK_ENABLE;
+		wait_bits = XE2LPD_DDI_BUF_D2D_LINK_STATE;
+	} else {
+		reg = XELPDP_PORT_BUF_CTL1(port);
+		clr_bits = XELPDP_PORT_BUF_D2D_LINK_ENABLE;
+		wait_bits = XELPDP_PORT_BUF_D2D_LINK_STATE;
+	}
 
-	if (wait_for_us(!(intel_de_read(dev_priv, XELPDP_PORT_BUF_CTL1(port)) &
-			  XELPDP_PORT_BUF_D2D_LINK_STATE), 100))
-		drm_err(&dev_priv->drm, "Timeout waiting for D2D Link disable for PORT_BUF_CTL %c\n",
+	intel_de_rmw(dev_priv, reg, clr_bits, 0);
+	if (wait_for_us(!(intel_de_read(dev_priv, reg) & wait_bits), 100))
+		drm_err(&dev_priv->drm, "Timeout waiting for D2D Link disable for DDI/PORT_BUF_CTL %c\n",
 			port_name(port));
 }
 
@@ -3323,6 +3341,9 @@ static void intel_enable_ddi_hdmi(struct intel_atomic_state *state,
 			     XELPDP_PORT_WIDTH_MASK | XELPDP_PORT_REVERSAL, port_buf);
 
 		buf_ctl |= DDI_PORT_WIDTH(lane_count);
+
+		if (DISPLAY_VER(dev_priv) >= 20)
+			buf_ctl |= XE2LPD_DDI_BUF_D2D_LINK_ENABLE;
 	} else if (IS_ALDERLAKE_P(dev_priv) && intel_phy_is_tc(dev_priv, phy)) {
 		drm_WARN_ON(&dev_priv->drm, !intel_tc_port_in_legacy_mode(dig_port));
 		buf_ctl |= DDI_BUF_CTL_TC_PHY_OWNERSHIP;
@@ -3543,6 +3564,9 @@ static void mtl_ddi_prepare_link_retrain(struct intel_dp *intel_dp,
 
 	/* 6.i Configure and enable DDI_CTL_DE to start sending valid data to port slice */
 	intel_dp->DP |= DDI_BUF_CTL_ENABLE;
+	if (DISPLAY_VER(dev_priv) >= 20)
+		intel_dp->DP |= XE2LPD_DDI_BUF_D2D_LINK_ENABLE;
+
 	intel_de_write(dev_priv, DDI_BUF_CTL(port), intel_dp->DP);
 	intel_de_posting_read(dev_priv, DDI_BUF_CTL(port));
 

drivers/gpu/drm/i915/i915_reg.h

@@ -5690,6 +5690,8 @@ enum skl_power_gate {
 /* Known as DDI_CTL_DE in MTL+ */
 #define DDI_BUF_CTL(port) _MMIO_PORT(port, _DDI_BUF_CTL_A, _DDI_BUF_CTL_B)
 #define  DDI_BUF_CTL_ENABLE			(1 << 31)
+#define  XE2LPD_DDI_BUF_D2D_LINK_ENABLE		REG_BIT(29)
+#define  XE2LPD_DDI_BUF_D2D_LINK_STATE		REG_BIT(28)
 #define  DDI_BUF_TRANS_SELECT(n)	((n) << 24)
 #define  DDI_BUF_EMP_MASK			(0xf << 24)
 #define  DDI_BUF_PHY_LINK_RATE(r)		((r) << 20)