drm/i915/icl: Set TBT IO in Aux transaction

For a TBT sequence, we need to set the IO type to TBT
in  DDI_AUX_CTL.

v2: Avoid duplications.(Paulo)

Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1532648115-29795-2-git-send-email-anusha.srivatsa@intel.com

drivers/gpu/drm/i915/i915_reg.h

@@ -5558,6 +5558,7 @@ enum {
 #define   DP_AUX_CH_CTL_PSR_DATA_AUX_REG_SKL	(1 << 14)
 #define   DP_AUX_CH_CTL_FS_DATA_AUX_REG_SKL	(1 << 13)
 #define   DP_AUX_CH_CTL_GTC_DATA_AUX_REG_SKL	(1 << 12)
+#define   DP_AUX_CH_CTL_TBT_IO			(1 << 11)
 #define   DP_AUX_CH_CTL_FW_SYNC_PULSE_SKL_MASK (0x1f << 5)
 #define   DP_AUX_CH_CTL_FW_SYNC_PULSE_SKL(c) (((c) - 1) << 5)
 #define   DP_AUX_CH_CTL_SYNC_PULSE_SKL(c)   ((c) - 1)

drivers/gpu/drm/i915/intel_dp.c

@@ -1208,7 +1208,10 @@ static uint32_t skl_get_aux_send_ctl(struct intel_dp *intel_dp,
 				      int send_bytes,
 				      uint32_t unused)
 {
-	return DP_AUX_CH_CTL_SEND_BUSY |
+	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
+	uint32_t ret;
+
+	ret = DP_AUX_CH_CTL_SEND_BUSY |
 	      DP_AUX_CH_CTL_DONE |
 	      DP_AUX_CH_CTL_INTERRUPT |
 	      DP_AUX_CH_CTL_TIME_OUT_ERROR |
@@ -1217,6 +1220,11 @@ static uint32_t skl_get_aux_send_ctl(struct intel_dp *intel_dp,
 	      (send_bytes << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) |
 	      DP_AUX_CH_CTL_FW_SYNC_PULSE_SKL(32) |
 	      DP_AUX_CH_CTL_SYNC_PULSE_SKL(32);
+
+	if (intel_dig_port->tc_type == TC_PORT_TBT)
+		ret |= DP_AUX_CH_CTL_TBT_IO;
+
+	return ret;
 }
 
 static int