1 files changed, 61 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy.c b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
index 8d6fd3f1ac13..22595766eac5 100644
--- a/drivers/gpu/drm/i915/display/intel_cx0_phy.c
+++ b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
@@ -3294,6 +3294,16 @@ static void intel_cx0pll_disable(struct intel_encoder *encoder)
 	intel_cx0_phy_transaction_end(encoder, wakeref);
 }
 
+static bool intel_cx0_pll_is_enabled(struct intel_encoder *encoder)
+{
+	struct intel_display *display = to_intel_display(encoder);
+	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
+	u8 lane = dig_port->lane_reversal ? INTEL_CX0_LANE1 : INTEL_CX0_LANE0;
+
+	return intel_de_read(display, XELPDP_PORT_CLOCK_CTL(display, encoder->port)) &
+			     intel_cx0_get_pclk_pll_request(lane);
+}
+
 static void intel_mtl_tbt_pll_disable(struct intel_encoder *encoder)
 {
 	struct intel_display *display = to_intel_display(encoder);
@@ -3555,3 +3565,54 @@ void intel_cx0pll_state_verify(struct intel_atomic_state *state,
 	else
 		intel_c20pll_state_verify(new_crtc_state, crtc, encoder, &mpll_hw_state.c20);
 }
+
+/*
+ * WA 14022081154
+ * The dedicated display PHYs reset to a power state that blocks S0ix, increasing idle
+ * system power. After a system reset (cold boot, S3/4/5, warm reset) if a dedicated
+ * PHY is not being brought up shortly, use these steps to move the PHY to the lowest
+ * power state to save power. For PTL the workaround is needed only for port A. Port B
+ * is not connected.
+ *
+ * 1. Follow the PLL Enable Sequence, using any valid frequency such as DP 1.62 GHz.
+ *    This brings lanes out of reset and enables the PLL to allow powerdown to be moved
+ *    to the Disable state.
+ * 2. Follow PLL Disable Sequence. This moves powerdown to the Disable state and disables the PLL.
+ */
+void intel_cx0_pll_power_save_wa(struct intel_display *display)
+{
+	struct intel_encoder *encoder;
+
+	if (DISPLAY_VER(display) != 30)
+		return;
+
+	for_each_intel_encoder(display->drm, encoder) {
+		struct intel_cx0pll_state pll_state = {};
+		int port_clock = 162000;
+
+		if (!intel_encoder_is_dig_port(encoder))
+			continue;
+
+		if (!intel_encoder_is_c10phy(encoder))
+			continue;
+
+		if (intel_cx0_pll_is_enabled(encoder))
+			continue;
+
+		if (intel_c10pll_calc_state_from_table(encoder,
+						       mtl_c10_edp_tables,
+						       true, port_clock,
+						       &pll_state) < 0) {
+			drm_WARN_ON(display->drm,
+				    "Unable to calc C10 state from the tables\n");
+			continue;
+		}
+
+		drm_dbg_kms(display->drm,
+			    "[ENCODER:%d:%s] Applying power saving workaround on disabled PLL\n",
+			    encoder->base.base.id, encoder->base.name);
+
+		__intel_cx0pll_enable(encoder, &pll_state, true, port_clock, 4);
+		intel_cx0pll_disable(encoder);
+	}
+}