thunderbolt: Add CL1 support for USB4 and Titan Ridge routers

In this patch we add support for a second low power state of the link: CL1.
Low power states (called collectively CLx) are used to reduce
transmitter and receiver power when a high-speed lane is idle.
We enable it, if both sides of the link support it,
and only for the first hop router (i.e. the first device that connected
to the host router). This is needed for better thermal management.

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

1 files changed, 150 insertions, 27 deletions

diff --git a/drivers/thunderbolt/tmu.c b/drivers/thunderbolt/tmu.c
index 985ca43b8f39..e822ab90338b 100644
--- a/drivers/thunderbolt/tmu.c
+++ b/drivers/thunderbolt/tmu.c
@@ -11,6 +11,55 @@
 
 #include "tb.h"
 
+static int tb_switch_set_tmu_mode_params(struct tb_switch *sw,
+					 enum tb_switch_tmu_rate rate)
+{
+	u32 freq_meas_wind[2] = { 30, 800 };
+	u32 avg_const[2] = { 4, 8 };
+	u32 freq, avg, val;
+	int ret;
+
+	if (rate == TB_SWITCH_TMU_RATE_NORMAL) {
+		freq = freq_meas_wind[0];
+		avg = avg_const[0];
+	} else if (rate == TB_SWITCH_TMU_RATE_HIFI) {
+		freq = freq_meas_wind[1];
+		avg = avg_const[1];
+	} else {
+		return 0;
+	}
+
+	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
+			 sw->tmu.cap + TMU_RTR_CS_0, 1);
+	if (ret)
+		return ret;
+
+	val &= ~TMU_RTR_CS_0_FREQ_WIND_MASK;
+	val |= FIELD_PREP(TMU_RTR_CS_0_FREQ_WIND_MASK, freq);
+
+	ret = tb_sw_write(sw, &val, TB_CFG_SWITCH,
+			  sw->tmu.cap + TMU_RTR_CS_0, 1);
+	if (ret)
+		return ret;
+
+	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
+			 sw->tmu.cap + TMU_RTR_CS_15, 1);
+	if (ret)
+		return ret;
+
+	val &= ~TMU_RTR_CS_15_FREQ_AVG_MASK &
+		~TMU_RTR_CS_15_DELAY_AVG_MASK &
+		~TMU_RTR_CS_15_OFFSET_AVG_MASK &
+		~TMU_RTR_CS_15_ERROR_AVG_MASK;
+	val |=  FIELD_PREP(TMU_RTR_CS_15_FREQ_AVG_MASK, avg) |
+		FIELD_PREP(TMU_RTR_CS_15_DELAY_AVG_MASK, avg) |
+		FIELD_PREP(TMU_RTR_CS_15_OFFSET_AVG_MASK, avg) |
+		FIELD_PREP(TMU_RTR_CS_15_ERROR_AVG_MASK, avg);
+
+	return tb_sw_write(sw, &val, TB_CFG_SWITCH,
+			   sw->tmu.cap + TMU_RTR_CS_15, 1);
+}
+
 static const char *tb_switch_tmu_mode_name(const struct tb_switch *sw)
 {
 	bool root_switch = !tb_route(sw);
@@ -348,7 +397,7 @@ int tb_switch_tmu_disable(struct tb_switch *sw)
 
 
 	if (tb_route(sw)) {
-		bool unidirectional = tb_switch_tmu_hifi_is_enabled(sw, true);
+		bool unidirectional = sw->tmu.unidirectional;
 		struct tb_switch *parent = tb_switch_parent(sw);
 		struct tb_port *down, *up;
 		int ret;
@@ -412,6 +461,7 @@ static void __tb_switch_tmu_off(struct tb_switch *sw, bool unidirectional)
 	else
 		tb_switch_tmu_rate_write(sw, TB_SWITCH_TMU_RATE_OFF);
 
+	tb_switch_set_tmu_mode_params(sw, sw->tmu.rate);
 	tb_port_tmu_unidirectional_disable(down);
 	tb_port_tmu_unidirectional_disable(up);
 }
@@ -493,7 +543,11 @@ static int __tb_switch_tmu_enable_unidirectional(struct tb_switch *sw)
 
 	up = tb_upstream_port(sw);
 	down = tb_port_at(tb_route(sw), parent);
-	ret = tb_switch_tmu_rate_write(parent, TB_SWITCH_TMU_RATE_HIFI);
+	ret = tb_switch_tmu_rate_write(parent, sw->tmu.rate_request);
+	if (ret)
+		return ret;
+
+	ret = tb_switch_set_tmu_mode_params(sw, sw->tmu.rate_request);
 	if (ret)
 		return ret;
 
@@ -520,7 +574,83 @@ out:
 	return ret;
 }
 
-static int tb_switch_tmu_hifi_enable(struct tb_switch *sw)
+static void __tb_switch_tmu_change_mode_prev(struct tb_switch *sw)
+{
+	struct tb_switch *parent = tb_switch_parent(sw);
+	struct tb_port *down, *up;
+
+	down = tb_port_at(tb_route(sw), parent);
+	up = tb_upstream_port(sw);
+	/*
+	 * In case of any failure in one of the steps when change mode,
+	 * get back to the TMU configurations in previous mode.
+	 * In case of additional failures in the functions below,
+	 * ignore them since the caller shall already report a failure.
+	 */
+	tb_port_tmu_set_unidirectional(down, sw->tmu.unidirectional);
+	if (sw->tmu.unidirectional_request)
+		tb_switch_tmu_rate_write(parent, sw->tmu.rate);
+	else
+		tb_switch_tmu_rate_write(sw, sw->tmu.rate);
+
+	tb_switch_set_tmu_mode_params(sw, sw->tmu.rate);
+	tb_port_tmu_set_unidirectional(up, sw->tmu.unidirectional);
+}
+
+static int __tb_switch_tmu_change_mode(struct tb_switch *sw)
+{
+	struct tb_switch *parent = tb_switch_parent(sw);
+	struct tb_port *up, *down;
+	int ret;
+
+	up = tb_upstream_port(sw);
+	down = tb_port_at(tb_route(sw), parent);
+	ret = tb_port_tmu_set_unidirectional(down, sw->tmu.unidirectional_request);
+	if (ret)
+		goto out;
+
+	if (sw->tmu.unidirectional_request)
+		ret = tb_switch_tmu_rate_write(parent, sw->tmu.rate_request);
+	else
+		ret = tb_switch_tmu_rate_write(sw, sw->tmu.rate_request);
+	if (ret)
+		return ret;
+
+	ret = tb_switch_set_tmu_mode_params(sw, sw->tmu.rate_request);
+	if (ret)
+		return ret;
+
+	ret = tb_port_tmu_set_unidirectional(up, sw->tmu.unidirectional_request);
+	if (ret)
+		goto out;
+
+	ret = tb_port_tmu_time_sync_enable(down);
+	if (ret)
+		goto out;
+
+	ret = tb_port_tmu_time_sync_enable(up);
+	if (ret)
+		goto out;
+
+	return 0;
+
+out:
+	__tb_switch_tmu_change_mode_prev(sw);
+	return ret;
+}
+
+/**
+ * tb_switch_tmu_enable() - Enable TMU on a router
+ * @sw: Router whose TMU to enable
+ *
+ * Enables TMU of a router to be in uni-directional Normal/HiFi
+ * or bi-directional HiFi mode. Calling tb_switch_tmu_configure() is required
+ * before calling this function, to select the mode Normal/HiFi and
+ * directionality (uni-directional/bi-directional).
+ * In HiFi mode all tunneling should work. In Normal mode, DP tunneling can't
+ * work. Uni-directional mode is required for CLx (Link Low-Power) to work.
+ */
+int tb_switch_tmu_enable(struct tb_switch *sw)
 {
 	bool unidirectional = sw->tmu.unidirectional_request;
 	int ret;
@@ -536,12 +666,15 @@ static int tb_switch_tmu_hifi_enable(struct tb_switch *sw)
 	if (!tb_switch_is_clx_supported(sw))
 		return 0;
 
-	if (tb_switch_tmu_hifi_is_enabled(sw, sw->tmu.unidirectional_request))
+	if (tb_switch_tmu_is_enabled(sw, sw->tmu.unidirectional_request))
 		return 0;
 
 	if (tb_switch_is_titan_ridge(sw) && unidirectional) {
-		/* Titan Ridge supports only CL0s */
-		if (!tb_switch_is_cl0s_enabled(sw))
+		/*
+		 * Titan Ridge supports CL0s and CL1 only. CL0s and CL1 are
+		 * enabled and supported together.
+		 */
+		if (!tb_switch_is_clx_enabled(sw, TB_CL1))
 			return -EOPNOTSUPP;
 
 		ret = tb_switch_tmu_objection_mask(sw);
@@ -558,7 +691,11 @@ static int tb_switch_tmu_hifi_enable(struct tb_switch *sw)
 		return ret;
 
 	if (tb_route(sw)) {
-		/* The used mode changes are from OFF to HiFi-Uni/HiFi-BiDir */
+		/*
+		 * The used mode changes are from OFF to
+		 * HiFi-Uni/HiFi-BiDir/Normal-Uni or from Normal-Uni to
+		 * HiFi-Uni.
+		 */
 		if (sw->tmu.rate == TB_SWITCH_TMU_RATE_OFF) {
 			if (unidirectional)
 				ret = __tb_switch_tmu_enable_unidirectional(sw);
@@ -566,6 +703,10 @@ static int tb_switch_tmu_hifi_enable(struct tb_switch *sw)
 				ret = __tb_switch_tmu_enable_bidirectional(sw);
 			if (ret)
 				return ret;
+		} else if (sw->tmu.rate == TB_SWITCH_TMU_RATE_NORMAL) {
+			ret = __tb_switch_tmu_change_mode(sw);
+			if (ret)
+				return ret;
 		}
 		sw->tmu.unidirectional = unidirectional;
 	} else {
@@ -575,36 +716,18 @@ static int tb_switch_tmu_hifi_enable(struct tb_switch *sw)
 		 * of the child node - see above.
 		 * Here only the host router' rate configuration is written.
 		 */
-		ret = tb_switch_tmu_rate_write(sw, TB_SWITCH_TMU_RATE_HIFI);
+		ret = tb_switch_tmu_rate_write(sw, sw->tmu.rate_request);
 		if (ret)
 			return ret;
 	}
 
-	sw->tmu.rate = TB_SWITCH_TMU_RATE_HIFI;
+	sw->tmu.rate = sw->tmu.rate_request;
 
 	tb_sw_dbg(sw, "TMU: mode set to: %s\n", tb_switch_tmu_mode_name(sw));
 	return tb_switch_tmu_set_time_disruption(sw, false);
 }
 
 /**
- * tb_switch_tmu_enable() - Enable TMU on a router
- * @sw: Router whose TMU to enable
- *
- * Enables TMU of a router to be in uni-directional or bi-directional HiFi mode.
- * Calling tb_switch_tmu_configure() is required before calling this function,
- * to select the mode HiFi and directionality (uni-directional/bi-directional).
- * In both modes all tunneling should work. Uni-directional mode is required for
- * CLx (Link Low-Power) to work.
- */
-int tb_switch_tmu_enable(struct tb_switch *sw)
-{
-	if (sw->tmu.rate_request == TB_SWITCH_TMU_RATE_NORMAL)
-		return -EOPNOTSUPP;
-
-	return tb_switch_tmu_hifi_enable(sw);
-}
-
-/**
  * tb_switch_tmu_configure() - Configure the TMU rate and directionality
  * @sw: Router whose mode to change
  * @rate: Rate to configure Off/Normal/HiFi