[Intel-gfx] [PATCH] drm/i915/tc: Implement the TC cold exit sequence

[José Roberto de Souza]

This is required for legacy/static TC ports as IOM is not aware of
the connection and will not trigger the TC cold exit.

BSpec: 21750
BSpsc: 49294
Cc: Imre Deak <imre.deak at intel.com>
Cc: Lucas De Marchi <lucas.demarchi at intel.com>
Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
---
 drivers/gpu/drm/i915/display/intel_tc.c | 34 ++++++++++++++++++++-----
 drivers/gpu/drm/i915/i915_reg.h         |  1 +
 2 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c
index 7773169b7331..09b78027bdd5 100644
--- a/drivers/gpu/drm/i915/display/intel_tc.c
+++ b/drivers/gpu/drm/i915/display/intel_tc.c
@@ -7,6 +7,7 @@
 #include "intel_display.h"
 #include "intel_display_types.h"
 #include "intel_dp_mst.h"
+#include "intel_sideband.h"
 #include "intel_tc.h"
 
 static const char *tc_port_mode_name(enum tc_port_mode mode)
@@ -169,6 +170,22 @@ static void tc_port_fixup_legacy_flag(struct intel_digital_port *dig_port,
 	dig_port->tc_legacy_port = !dig_port->tc_legacy_port;
 }
 
+static int tc_cold_exit_request(struct drm_i915_private *dev_priv)
+{
+	int ret;
+
+	do {
+		ret = sandybridge_pcode_write_timeout(dev_priv,
+						      ICL_PCODE_EXIT_TCCOLD, 0,
+						      250, 1);
+
+	} while (ret == -EAGAIN);
+
+	DRM_DEBUG_KMS("tccold exit %s\n", ret == 0 ? "succeeded" : "failed");
+
+	return ret;
+}
+
 static u32 tc_port_live_status_mask(struct intel_digital_port *dig_port)
 {
 	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
@@ -177,13 +194,21 @@ static u32 tc_port_live_status_mask(struct intel_digital_port *dig_port)
 	u32 mask = 0;
 	u32 val;
 
+	if (intel_uncore_read(uncore, SDEISR) & SDE_TC_HOTPLUG_ICP(tc_port))
+		mask |= BIT(TC_PORT_LEGACY);
+
 	val = intel_uncore_read(uncore,
 				PORT_TX_DFLEXDPSP(dig_port->tc_phy_fia));
 
 	if (val == 0xffffffff) {
-		DRM_DEBUG_KMS("Port %s: PHY in TCCOLD, nothing connected\n",
-			      dig_port->tc_port_name);
-		return mask;
+		if (mask)
+			tc_cold_exit_request(i915);
+
+		if (val == 0xffffffff) {
+			DRM_DEBUG_KMS("Port %s: PHY in TCCOLD, nothing connected\n",
+				      dig_port->tc_port_name);
+			return mask;
+		}
 	}
 
 	if (val & TC_LIVE_STATE_TBT(dig_port->tc_phy_fia_idx))
@@ -191,9 +216,6 @@ static u32 tc_port_live_status_mask(struct intel_digital_port *dig_port)
 	if (val & TC_LIVE_STATE_TC(dig_port->tc_phy_fia_idx))
 		mask |= BIT(TC_PORT_DP_ALT);
 
-	if (intel_uncore_read(uncore, SDEISR) & SDE_TC_HOTPLUG_ICP(tc_port))
-		mask |= BIT(TC_PORT_LEGACY);
-
 	/* The sink can be connected only in a single mode. */
 	if (!WARN_ON(hweight32(mask) > 1))
 		tc_port_fixup_legacy_flag(dig_port, mask);
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 058aa5ca8b73..35c3724b7fef 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -8860,6 +8860,7 @@ enum {
 #define     ICL_PCODE_MEM_SS_READ_QGV_POINT_INFO(point)	(((point) << 16) | (0x1 << 8))
 #define   GEN6_PCODE_READ_D_COMP		0x10
 #define   GEN6_PCODE_WRITE_D_COMP		0x11
+#define   ICL_PCODE_EXIT_TCCOLD			0x12
 #define   HSW_PCODE_DE_WRITE_FREQ_REQ		0x17
 #define   DISPLAY_IPS_CONTROL			0x19
             /* See also IPS_CTL */
-- 
2.23.0