thunderbolt: Move CLx support functions into clx.c

There really don't belong to switch.c so move them into their own file.
As we do this rename the functions to match the conventions used
elsewhere in the driver.

No functional changes.

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

1 files changed, 362 insertions, 0 deletions

diff --git a/drivers/thunderbolt/clx.c b/drivers/thunderbolt/clx.c
new file mode 100644
index 000000000000..d5b46a8e57c9
--- /dev/null
+++ b/drivers/thunderbolt/clx.c
@@ -0,0 +1,362 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CLx support
+ *
+ * Copyright (C) 2020 - 2023, Intel Corporation
+ * Authors: Gil Fine <gil.fine@intel.com>
+ *	    Mika Westerberg <mika.westerberg@linux.intel.com>
+ */
+
+#include <linux/module.h>
+
+#include "tb.h"
+
+static bool clx_enabled = true;
+module_param_named(clx, clx_enabled, bool, 0444);
+MODULE_PARM_DESC(clx, "allow low power states on the high-speed lanes (default: true)");
+
+static int tb_port_pm_secondary_set(struct tb_port *port, bool secondary)
+{
+	u32 phy;
+	int ret;
+
+	ret = tb_port_read(port, &phy, TB_CFG_PORT,
+			   port->cap_phy + LANE_ADP_CS_1, 1);
+	if (ret)
+		return ret;
+
+	if (secondary)
+		phy |= LANE_ADP_CS_1_PMS;
+	else
+		phy &= ~LANE_ADP_CS_1_PMS;
+
+	return tb_port_write(port, &phy, TB_CFG_PORT,
+			     port->cap_phy + LANE_ADP_CS_1, 1);
+}
+
+static int tb_port_pm_secondary_enable(struct tb_port *port)
+{
+	return tb_port_pm_secondary_set(port, true);
+}
+
+static int tb_port_pm_secondary_disable(struct tb_port *port)
+{
+	return tb_port_pm_secondary_set(port, false);
+}
+
+/* Called for USB4 or Titan Ridge routers only */
+static bool tb_port_clx_supported(struct tb_port *port, unsigned int clx_mask)
+{
+	u32 val, mask = 0;
+	bool ret;
+
+	/* Don't enable CLx in case of two single-lane links */
+	if (!port->bonded && port->dual_link_port)
+		return false;
+
+	/* Don't enable CLx in case of inter-domain link */
+	if (port->xdomain)
+		return false;
+
+	if (tb_switch_is_usb4(port->sw)) {
+		if (!usb4_port_clx_supported(port))
+			return false;
+	} else if (!tb_lc_is_clx_supported(port)) {
+		return false;
+	}
+
+	if (clx_mask & TB_CL1) {
+		/* CL0s and CL1 are enabled and supported together */
+		mask |= LANE_ADP_CS_0_CL0S_SUPPORT | LANE_ADP_CS_0_CL1_SUPPORT;
+	}
+	if (clx_mask & TB_CL2)
+		mask |= LANE_ADP_CS_0_CL2_SUPPORT;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_phy + LANE_ADP_CS_0, 1);
+	if (ret)
+		return false;
+
+	return !!(val & mask);
+}
+
+static int tb_port_clx_set(struct tb_port *port, enum tb_clx clx, bool enable)
+{
+	u32 phy, mask;
+	int ret;
+
+	/* CL0s and CL1 are enabled and supported together */
+	if (clx == TB_CL1)
+		mask = LANE_ADP_CS_1_CL0S_ENABLE | LANE_ADP_CS_1_CL1_ENABLE;
+	else
+		/* For now we support only CL0s and CL1. Not CL2 */
+		return -EOPNOTSUPP;
+
+	ret = tb_port_read(port, &phy, TB_CFG_PORT,
+			   port->cap_phy + LANE_ADP_CS_1, 1);
+	if (ret)
+		return ret;
+
+	if (enable)
+		phy |= mask;
+	else
+		phy &= ~mask;
+
+	return tb_port_write(port, &phy, TB_CFG_PORT,
+			     port->cap_phy + LANE_ADP_CS_1, 1);
+}
+
+static int tb_port_clx_disable(struct tb_port *port, enum tb_clx clx)
+{
+	return tb_port_clx_set(port, clx, false);
+}
+
+static int tb_port_clx_enable(struct tb_port *port, enum tb_clx clx)
+{
+	return tb_port_clx_set(port, clx, true);
+}
+
+/**
+ * tb_port_clx_is_enabled() - Is given CL state enabled
+ * @port: USB4 port to check
+ * @clx_mask: Mask of CL states to check
+ *
+ * Returns true if any of the given CL states is enabled for @port.
+ */
+bool tb_port_clx_is_enabled(struct tb_port *port, unsigned int clx_mask)
+{
+	u32 val, mask = 0;
+	int ret;
+
+	if (!tb_port_clx_supported(port, clx_mask))
+		return false;
+
+	if (clx_mask & TB_CL1)
+		mask |= LANE_ADP_CS_1_CL0S_ENABLE | LANE_ADP_CS_1_CL1_ENABLE;
+	if (clx_mask & TB_CL2)
+		mask |= LANE_ADP_CS_1_CL2_ENABLE;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_phy + LANE_ADP_CS_1, 1);
+	if (ret)
+		return false;
+
+	return !!(val & mask);
+}
+
+static int tb_switch_pm_secondary_resolve(struct tb_switch *sw)
+{
+	struct tb_port *up, *down;
+	int ret;
+
+	if (!tb_route(sw))
+		return 0;
+
+	up = tb_upstream_port(sw);
+	down = tb_switch_downstream_port(sw);
+	ret = tb_port_pm_secondary_enable(up);
+	if (ret)
+		return ret;
+
+	return tb_port_pm_secondary_disable(down);
+}
+
+static int tb_switch_mask_clx_objections(struct tb_switch *sw)
+{
+	int up_port = sw->config.upstream_port_number;
+	u32 offset, val[2], mask_obj, unmask_obj;
+	int ret, i;
+
+	/* Only Titan Ridge of pre-USB4 devices support CLx states */
+	if (!tb_switch_is_titan_ridge(sw))
+		return 0;
+
+	if (!tb_route(sw))
+		return 0;
+
+	/*
+	 * In Titan Ridge there are only 2 dual-lane Thunderbolt ports:
+	 * Port A consists of lane adapters 1,2 and
+	 * Port B consists of lane adapters 3,4
+	 * If upstream port is A, (lanes are 1,2), we mask objections from
+	 * port B (lanes 3,4) and unmask objections from Port A and vice-versa.
+	 */
+	if (up_port == 1) {
+		mask_obj = TB_LOW_PWR_C0_PORT_B_MASK;
+		unmask_obj = TB_LOW_PWR_C1_PORT_A_MASK;
+		offset = TB_LOW_PWR_C1_CL1;
+	} else {
+		mask_obj = TB_LOW_PWR_C1_PORT_A_MASK;
+		unmask_obj = TB_LOW_PWR_C0_PORT_B_MASK;
+		offset = TB_LOW_PWR_C3_CL1;
+	}
+
+	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
+			 sw->cap_lp + offset, ARRAY_SIZE(val));
+	if (ret)
+		return ret;
+
+	for (i = 0; i < ARRAY_SIZE(val); i++) {
+		val[i] |= mask_obj;
+		val[i] &= ~unmask_obj;
+	}
+
+	return tb_sw_write(sw, &val, TB_CFG_SWITCH,
+			   sw->cap_lp + offset, ARRAY_SIZE(val));
+}
+
+static int __tb_switch_enable_clx(struct tb_switch *sw, enum tb_clx clx)
+{
+	bool up_clx_support, down_clx_support;
+	struct tb_port *up, *down;
+	int ret;
+
+	if (!tb_switch_clx_is_supported(sw))
+		return 0;
+
+	/*
+	 * Enable CLx for host router's downstream port as part of the
+	 * downstream router enabling procedure.
+	 */
+	if (!tb_route(sw))
+		return 0;
+
+	/* Enable CLx only for first hop router (depth = 1) */
+	if (tb_route(tb_switch_parent(sw)))
+		return 0;
+
+	ret = tb_switch_pm_secondary_resolve(sw);
+	if (ret)
+		return ret;
+
+	up = tb_upstream_port(sw);
+	down = tb_switch_downstream_port(sw);
+
+	up_clx_support = tb_port_clx_supported(up, clx);
+	down_clx_support = tb_port_clx_supported(down, clx);
+
+	tb_port_dbg(up, "%s %ssupported\n", tb_switch_clx_name(clx),
+		    up_clx_support ? "" : "not ");
+	tb_port_dbg(down, "%s %ssupported\n", tb_switch_clx_name(clx),
+		    down_clx_support ? "" : "not ");
+
+	if (!up_clx_support || !down_clx_support)
+		return -EOPNOTSUPP;
+
+	ret = tb_port_clx_enable(up, clx);
+	if (ret)
+		return ret;
+
+	ret = tb_port_clx_enable(down, clx);
+	if (ret) {
+		tb_port_clx_disable(up, clx);
+		return ret;
+	}
+
+	ret = tb_switch_mask_clx_objections(sw);
+	if (ret) {
+		tb_port_clx_disable(up, clx);
+		tb_port_clx_disable(down, clx);
+		return ret;
+	}
+
+	sw->clx = clx;
+
+	tb_port_dbg(up, "%s enabled\n", tb_switch_clx_name(clx));
+	return 0;
+}
+
+/**
+ * tb_switch_clx_enable() - Enable CLx on upstream port of specified router
+ * @sw: Router to enable CLx for
+ * @clx: The CLx state to enable
+ *
+ * Enable CLx state only for first hop router. That is the most common
+ * use-case, that is intended for better thermal management, and so helps
+ * to improve performance. CLx is enabled only if both sides of the link
+ * support CLx, and if both sides of the link are not configured as two
+ * single lane links and only if the link is not inter-domain link. The
+ * complete set of conditions is described in CM Guide 1.0 section 8.1.
+ *
+ * Return: Returns 0 on success or an error code on failure.
+ */
+int tb_switch_clx_enable(struct tb_switch *sw, enum tb_clx clx)
+{
+	struct tb_switch *root_sw = sw->tb->root_switch;
+
+	if (!clx_enabled)
+		return 0;
+
+	/*
+	 * CLx is not enabled and validated on Intel USB4 platforms before
+	 * Alder Lake.
+	 */
+	if (root_sw->generation < 4 || tb_switch_is_tiger_lake(root_sw))
+		return 0;
+
+	switch (clx) {
+	case TB_CL1:
+		/* CL0s and CL1 are enabled and supported together */
+		return __tb_switch_enable_clx(sw, clx);
+
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int __tb_switch_disable_clx(struct tb_switch *sw, enum tb_clx clx)
+{
+	struct tb_port *up, *down;
+	int ret;
+
+	if (!tb_switch_clx_is_supported(sw))
+		return 0;
+
+	/*
+	 * Disable CLx for host router's downstream port as part of the
+	 * downstream router enabling procedure.
+	 */
+	if (!tb_route(sw))
+		return 0;
+
+	/* Disable CLx only for first hop router (depth = 1) */
+	if (tb_route(tb_switch_parent(sw)))
+		return 0;
+
+	up = tb_upstream_port(sw);
+	down = tb_switch_downstream_port(sw);
+	ret = tb_port_clx_disable(up, clx);
+	if (ret)
+		return ret;
+
+	ret = tb_port_clx_disable(down, clx);
+	if (ret)
+		return ret;
+
+	sw->clx = TB_CLX_DISABLE;
+
+	tb_port_dbg(up, "%s disabled\n", tb_switch_clx_name(clx));
+	return 0;
+}
+
+/**
+ * tb_switch_cls_disable() - Disable CLx on upstream port of specified router
+ * @sw: Router to disable CLx for
+ * @clx: The CLx state to disable
+ *
+ * Return: Returns 0 on success or an error code on failure.
+ */
+int tb_switch_clx_disable(struct tb_switch *sw, enum tb_clx clx)
+{
+	if (!clx_enabled)
+		return 0;
+
+	switch (clx) {
+	case TB_CL1:
+		/* CL0s and CL1 are enabled and supported together */
+		return __tb_switch_disable_clx(sw, clx);
+
+	default:
+		return -EOPNOTSUPP;
+	}
+}