thunderbolt: Add support for native USB4 _OSC

ACPI 6.4 introduced a new _OSC capability used to negotiate whether the
OS is supposed to use Software (native) or Firmware based Connection
Manager. If the native support is granted then there are set of bits
that enable/disable different tunnel types that the Software Connection
Manager is allowed to tunnel.

This adds support for this new USB4 _OSC accordingly. When PCIe
tunneling is disabled then the driver switches security level to be
"nopcie" following the security level 5 used in Firmware based
Connection Manager.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Yehezkel Bernat <YehezkelShB@gmail.com>

drivers/thunderbolt/acpi.c

@@ -115,3 +115,68 @@ void tb_acpi_add_links(struct tb_nhi *nhi)
 	if (ACPI_FAILURE(status))
 		dev_warn(&nhi->pdev->dev, "failed to enumerate tunneled ports\n");
 }
+
+/**
+ * tb_acpi_is_native() - Did the platform grant native TBT/USB4 control
+ *
+ * Returns %true if the platform granted OS native control over
+ * TBT/USB4. In this case software based connection manager can be used,
+ * otherwise there is firmware based connection manager running.
+ */
+bool tb_acpi_is_native(void)
+{
+	return osc_sb_native_usb4_support_confirmed &&
+	       osc_sb_native_usb4_control;
+}
+
+/**
+ * tb_acpi_may_tunnel_usb3() - Is USB3 tunneling allowed by the platform
+ *
+ * When software based connection manager is used, this function
+ * returns %true if platform allows native USB3 tunneling.
+ */
+bool tb_acpi_may_tunnel_usb3(void)
+{
+	if (tb_acpi_is_native())
+		return osc_sb_native_usb4_control & OSC_USB_USB3_TUNNELING;
+	return true;
+}
+
+/**
+ * tb_acpi_may_tunnel_dp() - Is DisplayPort tunneling allowed by the platform
+ *
+ * When software based connection manager is used, this function
+ * returns %true if platform allows native DP tunneling.
+ */
+bool tb_acpi_may_tunnel_dp(void)
+{
+	if (tb_acpi_is_native())
+		return osc_sb_native_usb4_control & OSC_USB_DP_TUNNELING;
+	return true;
+}
+
+/**
+ * tb_acpi_may_tunnel_pcie() - Is PCIe tunneling allowed by the platform
+ *
+ * When software based connection manager is used, this function
+ * returns %true if platform allows native PCIe tunneling.
+ */
+bool tb_acpi_may_tunnel_pcie(void)
+{
+	if (tb_acpi_is_native())
+		return osc_sb_native_usb4_control & OSC_USB_PCIE_TUNNELING;
+	return true;
+}
+
+/**
+ * tb_acpi_is_xdomain_allowed() - Are XDomain connections allowed
+ *
+ * When software based connection manager is used, this function
+ * returns %true if platform allows XDomain connections.
+ */
+bool tb_acpi_is_xdomain_allowed(void)
+{
+	if (tb_acpi_is_native())
+		return osc_sb_native_usb4_control & OSC_USB_XDOMAIN;
+	return true;
+}

drivers/thunderbolt/nhi.c

@@ -1190,6 +1190,29 @@ static void tb_apple_add_links(struct tb_nhi *nhi)
 	}
 }
 
+static struct tb *nhi_select_cm(struct tb_nhi *nhi)
+{
+	struct tb *tb;
+
+	/*
+	 * USB4 case is simple. If we got control of any of the
+	 * capabilities, we use software CM.
+	 */
+	if (tb_acpi_is_native())
+		return tb_probe(nhi);
+
+	/*
+	 * Either firmware based CM is running (we did not get control
+	 * from the firmware) or this is pre-USB4 PC so try first
+	 * firmware CM and then fallback to software CM.
+	 */
+	tb = icm_probe(nhi);
+	if (!tb)
+		tb = tb_probe(nhi);
+
+	return tb;
+}
+
 static int nhi_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	struct tb_nhi *nhi;
@@ -1258,9 +1281,7 @@ static int nhi_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	tb_apple_add_links(nhi);
 	tb_acpi_add_links(nhi);
 
-	tb = icm_probe(nhi);
-	if (!tb)
-		tb = tb_probe(nhi);
+	tb = nhi_select_cm(nhi);
 	if (!tb) {
 		dev_err(&nhi->pdev->dev,
 			"failed to determine connection manager, aborting\n");

drivers/thunderbolt/tb.c

@@ -437,6 +437,11 @@ static int tb_tunnel_usb3(struct tb *tb, struct tb_switch *sw)
 	struct tb_cm *tcm = tb_priv(tb);
 	struct tb_tunnel *tunnel;
 
+	if (!tb_acpi_may_tunnel_usb3()) {
+		tb_dbg(tb, "USB3 tunneling disabled, not creating tunnel\n");
+		return 0;
+	}
+
 	up = tb_switch_find_port(sw, TB_TYPE_USB3_UP);
 	if (!up)
 		return 0;
@@ -512,6 +517,9 @@ static int tb_create_usb3_tunnels(struct tb_switch *sw)
 	struct tb_port *port;
 	int ret;
 
+	if (!tb_acpi_may_tunnel_usb3())
+		return 0;
+
 	if (tb_route(sw)) {
 		ret = tb_tunnel_usb3(sw->tb, sw);
 		if (ret)
@@ -841,6 +849,11 @@ static void tb_tunnel_dp(struct tb *tb)
 	struct tb_port *port, *in, *out;
 	struct tb_tunnel *tunnel;
 
+	if (!tb_acpi_may_tunnel_dp()) {
+		tb_dbg(tb, "DP tunneling disabled, not creating tunnel\n");
+		return;
+	}
+
 	/*
 	 * Find pair of inactive DP IN and DP OUT adapters and then
 	 * establish a DP tunnel between them.
@@ -1549,7 +1562,11 @@ struct tb *tb_probe(struct tb_nhi *nhi)
 	if (!tb)
 		return NULL;
 
-	tb->security_level = TB_SECURITY_USER;
+	if (tb_acpi_may_tunnel_pcie())
+		tb->security_level = TB_SECURITY_USER;
+	else
+		tb->security_level = TB_SECURITY_NOPCIE;
+
 	tb->cm_ops = &tb_cm_ops;
 
 	tcm = tb_priv(tb);

drivers/thunderbolt/tb.h

@@ -1044,8 +1044,20 @@ void tb_check_quirks(struct tb_switch *sw);
 
 #ifdef CONFIG_ACPI
 void tb_acpi_add_links(struct tb_nhi *nhi);
+
+bool tb_acpi_is_native(void);
+bool tb_acpi_may_tunnel_usb3(void);
+bool tb_acpi_may_tunnel_dp(void);
+bool tb_acpi_may_tunnel_pcie(void);
+bool tb_acpi_is_xdomain_allowed(void);
 #else
 static inline void tb_acpi_add_links(struct tb_nhi *nhi) { }
+
+static inline bool tb_acpi_is_native(void) { return true; }
+static inline bool tb_acpi_may_tunnel_usb3(void) { return true; }
+static inline bool tb_acpi_may_tunnel_dp(void) { return true; }
+static inline bool tb_acpi_may_tunnel_pcie(void) { return true; }
+static inline bool tb_acpi_is_xdomain_allowed(void) { return true; }
 #endif
 
 #ifdef CONFIG_DEBUG_FS

drivers/thunderbolt/tunnel.c

@@ -932,12 +932,14 @@ static int tb_usb3_activate(struct tb_tunnel *tunnel, bool activate)
 static int tb_usb3_consumed_bandwidth(struct tb_tunnel *tunnel,
 		int *consumed_up, int *consumed_down)
 {
+	int pcie_enabled = tb_acpi_may_tunnel_pcie();
+
 	/*
-	 * PCIe tunneling affects the USB3 bandwidth so take that it
-	 * into account here.
+	 * PCIe tunneling, if enabled, affects the USB3 bandwidth so
+	 * take that it into account here.
 	 */
-	*consumed_up = tunnel->allocated_up * (3 + 1) / 3;
-	*consumed_down = tunnel->allocated_down * (3 + 1) / 3;
+	*consumed_up = tunnel->allocated_up * (3 + pcie_enabled) / 3;
+	*consumed_down = tunnel->allocated_down * (3 + pcie_enabled) / 3;
 	return 0;
 }
 

drivers/thunderbolt/usb4.c

@@ -331,13 +331,18 @@ int usb4_switch_setup(struct tb_switch *sw)
 	if (ret)
 		return ret;
 
-	if (sw->link_usb4 && tb_switch_find_port(parent, TB_TYPE_USB3_DOWN)) {
+	if (tb_acpi_may_tunnel_usb3() && sw->link_usb4 &&
+	    tb_switch_find_port(parent, TB_TYPE_USB3_DOWN)) {
 		val |= ROUTER_CS_5_UTO;
 		xhci = false;
 	}
 
-	/* Only enable PCIe tunneling if the parent router supports it */
-	if (tb_switch_find_port(parent, TB_TYPE_PCIE_DOWN)) {
+	/*
+	 * Only enable PCIe tunneling if the parent router supports it
+	 * and it is not disabled.
+	 */
+	if (tb_acpi_may_tunnel_pcie() &&
+	    tb_switch_find_port(parent, TB_TYPE_PCIE_DOWN)) {
 		val |= ROUTER_CS_5_PTO;
 		/*
 		 * xHCI can be enabled if PCIe tunneling is supported

drivers/thunderbolt/xdomain.c

@@ -53,7 +53,7 @@ static const uuid_t tb_xdp_uuid =
 
 bool tb_is_xdomain_enabled(void)
 {
-	return tb_xdomain_enabled;
+	return tb_xdomain_enabled && tb_acpi_is_xdomain_allowed();
 }
 
 static bool tb_xdomain_match(const struct tb_cfg_request *req,