drm/i915/hdcp: Disable HDCP Line Rekeying for HDCP2.2 on HDMI

Disable HDCP Line Rekeying when HDCP ver > 1.4 and when we are
on HDMI TMDS operation for DISPLAY_VER >= 14.

--v2
-Wa to be mentioned in comments not in commit message [Jani]
-Remove blankline [Jani]

--v3
-No need to write what is being done in comments when code
is self explanatory [Jani]

--v4
-Add comment regarding need of this WA when in TMDS mode
[Chaitanya]
-Write in chicken register for MTL [CHaitanya]

--v5
-Fix comment [Chaitanya]
-Use correct set and clear value in intel_de_rmw [Chaitanya]

--v6
-No need to define C, D chicken bits it gets calculated [Animesh]

Bspec: 49273
Bspec: 69964
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240507062243.1076047-2-suraj.kandpal@intel.com

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

@@ -30,6 +30,27 @@
 #define KEY_LOAD_TRIES	5
 #define HDCP2_LC_RETRY_CNT			3
 
+/* WA: 16022217614 */
+static void
+intel_hdcp_disable_hdcp_line_rekeying(struct intel_encoder *encoder,
+				      struct intel_hdcp *hdcp)
+{
+	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+
+	/* Here we assume HDMI is in TMDS mode of operation */
+	if (encoder->type != INTEL_OUTPUT_HDMI)
+		return;
+
+	if (DISPLAY_VER(dev_priv) >= 14) {
+		if (IS_METEORLAKE(dev_priv))
+			intel_de_rmw(dev_priv, MTL_CHICKEN_TRANS(hdcp->cpu_transcoder),
+				     0, HDCP_LINE_REKEY_DISABLE);
+		else
+			intel_de_rmw(dev_priv, TRANS_DDI_FUNC_CTL(hdcp->cpu_transcoder),
+				     0, TRANS_DDI_HDCP_LINE_REKEY_DISABLE);
+	}
+}
+
 static int intel_conn_to_vcpi(struct intel_atomic_state *state,
 			      struct intel_connector *connector)
 {
@@ -2005,6 +2026,8 @@ static int _intel_hdcp2_enable(struct intel_atomic_state *state,
 		    connector->base.base.id, connector->base.name,
 		    hdcp->content_type);
 
+	intel_hdcp_disable_hdcp_line_rekeying(connector->encoder, hdcp);
+
 	ret = hdcp2_authenticate_and_encrypt(state, connector);
 	if (ret) {
 		drm_dbg_kms(&i915->drm, "HDCP2 Type%d  Enabling Failed. (%d)\n",

drivers/gpu/drm/i915/i915_reg.h

@@ -3520,6 +3520,7 @@
 #define   DP_FEC_BS_JITTER_WA		REG_BIT(15)
 #define   PSR2_VSC_ENABLE_PROG_HEADER	REG_BIT(12)
 #define   DP_DSC_INSERT_SF_AT_EOL_WA	REG_BIT(4)
+#define   HDCP_LINE_REKEY_DISABLE	REG_BIT(0)
 
 #define DISP_ARB_CTL	_MMIO(0x45000)
 #define   DISP_FBC_MEMORY_WAKE		REG_BIT(31)
@@ -4521,6 +4522,7 @@ enum skl_power_gate {
 #define  TRANS_DDI_EDP_INPUT_B_ONOFF	(5 << 12)
 #define  TRANS_DDI_EDP_INPUT_C_ONOFF	(6 << 12)
 #define  TRANS_DDI_EDP_INPUT_D_ONOFF	(7 << 12)
+#define  TRANS_DDI_HDCP_LINE_REKEY_DISABLE	REG_BIT(12)
 #define  TRANS_DDI_MST_TRANSPORT_SELECT_MASK	REG_GENMASK(11, 10)
 #define  TRANS_DDI_MST_TRANSPORT_SELECT(trans)	\
 	REG_FIELD_PREP(TRANS_DDI_MST_TRANSPORT_SELECT_MASK, trans)