4 files changed, 70 insertions, 3 deletions

diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 845e851012e5..002e0426a82c 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -1301,6 +1301,8 @@ int usb4_dp_port_allocated_bw(struct tb_port *port);
 int usb4_dp_port_allocate_bw(struct tb_port *port, int bw);
 int usb4_dp_port_requested_bw(struct tb_port *port);
 
+int usb4_pci_port_set_ext_encapsulation(struct tb_port *port, bool enable);
+
 static inline bool tb_is_usb4_port_device(const struct device *dev)
 {
 	return dev->type == &usb4_port_device_type;
diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h
index c8e40ef09903..549cc79c7313 100644
--- a/drivers/thunderbolt/tb_regs.h
+++ b/drivers/thunderbolt/tb_regs.h
@@ -451,6 +451,8 @@ struct tb_regs_port_header {
 /* PCIe adapter registers */
 #define ADP_PCIE_CS_0				0x00
 #define ADP_PCIE_CS_0_PE			BIT(31)
+#define ADP_PCIE_CS_1				0x01
+#define ADP_PCIE_CS_1_EE			BIT(0)
 
 /* USB adapter registers */
 #define ADP_USB3_CS_0				0x00
diff --git a/drivers/thunderbolt/tunnel.c b/drivers/thunderbolt/tunnel.c
index 7df5f90e21d4..c8ca0a41dac8 100644
--- a/drivers/thunderbolt/tunnel.c
+++ b/drivers/thunderbolt/tunnel.c
@@ -10,6 +10,7 @@
 #include <linux/slab.h>
 #include <linux/list.h>
 #include <linux/ktime.h>
+#include <linux/string_helpers.h>
 
 #include "tunnel.h"
 #include "tb.h"
@@ -153,18 +154,49 @@ static struct tb_tunnel *tb_tunnel_alloc(struct tb *tb, size_t npaths,
 	return tunnel;
 }
 
+static int tb_pci_set_ext_encapsulation(struct tb_tunnel *tunnel, bool enable)
+{
+	int ret;
+
+	/* Only supported of both routers are at least USB4 v2 */
+	if (usb4_switch_version(tunnel->src_port->sw) < 2 ||
+	    usb4_switch_version(tunnel->dst_port->sw) < 2)
+		return 0;
+
+	ret = usb4_pci_port_set_ext_encapsulation(tunnel->src_port, enable);
+	if (ret)
+		return ret;
+
+	ret = usb4_pci_port_set_ext_encapsulation(tunnel->dst_port, enable);
+	if (ret)
+		return ret;
+
+	tb_tunnel_dbg(tunnel, "extended encapsulation %s\n",
+		      str_enabled_disabled(enable));
+	return 0;
+}
+
 static int tb_pci_activate(struct tb_tunnel *tunnel, bool activate)
 {
 	int res;
 
+	if (activate) {
+		res = tb_pci_set_ext_encapsulation(tunnel, activate);
+		if (res)
+			return res;
+	}
+
 	res = tb_pci_port_enable(tunnel->src_port, activate);
 	if (res)
 		return res;
 
-	if (tb_port_is_pcie_up(tunnel->dst_port))
-		return tb_pci_port_enable(tunnel->dst_port, activate);
+	if (tb_port_is_pcie_up(tunnel->dst_port)) {
+		res = tb_pci_port_enable(tunnel->dst_port, activate);
+		if (res)
+			return res;
+	}
 
-	return 0;
+	return activate ? 0 : tb_pci_set_ext_encapsulation(tunnel, activate);
 }
 
 static int tb_pci_init_credits(struct tb_path_hop *hop)
diff --git a/drivers/thunderbolt/usb4.c b/drivers/thunderbolt/usb4.c
index 9f5a98347bee..302d8d3fbd5a 100644
--- a/drivers/thunderbolt/usb4.c
+++ b/drivers/thunderbolt/usb4.c
@@ -2796,3 +2796,34 @@ int usb4_dp_port_requested_bw(struct tb_port *port)
 
 	return (val & ADP_DP_CS_8_REQUESTED_BW_MASK) * granularity;
 }
+
+/**
+ * usb4_pci_port_set_ext_encapsulation() - Enable/disable extended encapsulation
+ * @port: PCIe adapter
+ * @enable: Enable/disable extended encapsulation
+ *
+ * Enables or disables extended encapsulation used in PCIe tunneling. Caller
+ * needs to make sure both adapters support this before enabling. Returns %0 on
+ * success and negative errno otherwise.
+ */
+int usb4_pci_port_set_ext_encapsulation(struct tb_port *port, bool enable)
+{
+	u32 val;
+	int ret;
+
+	if (!tb_port_is_pcie_up(port) && !tb_port_is_pcie_down(port))
+		return -EINVAL;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_PCIE_CS_1, 1);
+	if (ret)
+		return ret;
+
+	if (enable)
+		val |= ADP_PCIE_CS_1_EE;
+	else
+		val &= ~ADP_PCIE_CS_1_EE;
+
+	return tb_port_write(port, &val, TB_CFG_PORT,
+			     port->cap_adap + ADP_PCIE_CS_1, 1);
+}