thunderbolt: Add support for enhanced uni-directional TMU mode

This is new TMU mode introduced with the USB4 v2. This mode is simpler
than the existing ones and allows all CL states as well. Enable this for
all links where both side routers are v2 and keep the existing
functionality for the v1 and earlier links.

Currently only support the MedRes rate. We can add the HiFi rate later
too if it turns out to be useful.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

1 files changed, 44 insertions, 14 deletions

diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
index f18cb5a52f0b..ff034975a87e 100644
--- a/drivers/thunderbolt/tb.c
+++ b/drivers/thunderbolt/tb.c
@@ -297,11 +297,23 @@ static int tb_increase_switch_tmu_accuracy(struct device *dev, void *data)
 	struct tb_switch *sw;
 
 	sw = tb_to_switch(dev);
-	if (sw) {
-		tb_switch_tmu_configure(sw, TB_SWITCH_TMU_RATE_HIFI,
-					tb_switch_clx_is_enabled(sw, TB_CL1));
-		if (tb_switch_tmu_enable(sw))
-			tb_sw_warn(sw, "failed to increase TMU rate\n");
+	if (!sw)
+		return 0;
+
+	if (tb_switch_tmu_is_configured(sw, TB_SWITCH_TMU_MODE_LOWRES)) {
+		enum tb_switch_tmu_mode mode;
+		int ret;
+
+		if (tb_switch_clx_is_enabled(sw, TB_CL1))
+			mode = TB_SWITCH_TMU_MODE_HIFI_UNI;
+		else
+			mode = TB_SWITCH_TMU_MODE_HIFI_BI;
+
+		ret = tb_switch_tmu_configure(sw, mode);
+		if (ret)
+			return ret;
+
+		return tb_switch_tmu_enable(sw);
 	}
 
 	return 0;
@@ -319,6 +331,9 @@ static void tb_increase_tmu_accuracy(struct tb_tunnel *tunnel)
 	 * accuracy of first depth child routers (and the host router)
 	 * to the highest. This is needed for the DP tunneling to work
 	 * but also allows CL0s.
+	 *
+	 * If both routers are v2 then we don't need to do anything as
+	 * they are using enhanced TMU mode that allows all CLx.
 	 */
 	sw = tunnel->tb->root_switch;
 	device_for_each_child(&sw->dev, NULL, tb_increase_switch_tmu_accuracy);
@@ -329,14 +344,22 @@ static int tb_enable_tmu(struct tb_switch *sw)
 	int ret;
 
 	/*
-	 * If CL1 is enabled then we need to configure the TMU accuracy
-	 * level to normal. Otherwise we keep the TMU running at the
-	 * highest accuracy.
+	 * If both routers at the end of the link are v2 we simply
+	 * enable the enhanched uni-directional mode. That covers all
+	 * the CL states. For v1 and before we need to use the normal
+	 * rate to allow CL1 (when supported). Otherwise we keep the TMU
+	 * running at the highest accuracy.
 	 */
-	if (tb_switch_clx_is_enabled(sw, TB_CL1))
-		ret = tb_switch_tmu_configure(sw, TB_SWITCH_TMU_RATE_NORMAL, true);
-	else
-		ret = tb_switch_tmu_configure(sw, TB_SWITCH_TMU_RATE_HIFI, false);
+	ret = tb_switch_tmu_configure(sw,
+			TB_SWITCH_TMU_MODE_MEDRES_ENHANCED_UNI);
+	if (ret == -EOPNOTSUPP) {
+		if (tb_switch_clx_is_enabled(sw, TB_CL1))
+			ret = tb_switch_tmu_configure(sw,
+					TB_SWITCH_TMU_MODE_LOWRES);
+		else
+			ret = tb_switch_tmu_configure(sw,
+					TB_SWITCH_TMU_MODE_HIFI_BI);
+	}
 	if (ret)
 		return ret;
 
@@ -963,6 +986,12 @@ static void tb_scan_port(struct tb_port *port)
 	if (tb_enable_tmu(sw))
 		tb_sw_warn(sw, "failed to enable TMU\n");
 
+	/*
+	 * Configuration valid needs to be set after the TMU has been
+	 * enabled for the upstream port of the router so we do it here.
+	 */
+	tb_switch_configuration_valid(sw);
+
 	/* Scan upstream retimers */
 	tb_retimer_scan(upstream_port, true);
 
@@ -2086,8 +2115,7 @@ static int tb_start(struct tb *tb)
 	 * To support highest CLx state, we set host router's TMU to
 	 * Normal mode.
 	 */
-	tb_switch_tmu_configure(tb->root_switch, TB_SWITCH_TMU_RATE_NORMAL,
-				false);
+	tb_switch_tmu_configure(tb->root_switch, TB_SWITCH_TMU_MODE_LOWRES);
 	/* Enable TMU if it is off */
 	tb_switch_tmu_enable(tb->root_switch);
 	/* Full scan to discover devices added before the driver was loaded. */
@@ -2139,6 +2167,8 @@ static void tb_restore_children(struct tb_switch *sw)
 	if (tb_enable_tmu(sw))
 		tb_sw_warn(sw, "failed to restore TMU configuration\n");
 
+	tb_switch_configuration_valid(sw);
+
 	tb_switch_for_each_port(sw, port) {
 		if (!tb_port_has_remote(port) && !port->xdomain)
 			continue;