thunderbolt: Enable USB4 v2 PCIe TLP/DLLP extended encapsulation

USB4 v2 spec introduces modified encapsulation of PCIe TLP and DLLP
packets. This improves the PCIe tunneled traffic usage by reducing
overhead. Enable this if both sides of the link support it.

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

diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 845e851012e550b5e24617ea4a1366ac6d3f6ae4..002e0426a82c72d0f563b73685ff81a45e0d1a8d 100644 (file)
--- 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 c8e40ef09903edbda82b93f9214c2ad6d7c4acec..549cc79c7313dfd0fb80cba4c24486aa9b49a776 100644 (file)
--- 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 7df5f90e21d45c2ad8e3ddbc3a94ac5bfb2d7850..c8ca0a41dac8f07ef1e72c3742db22f06436a728 100644 (file)
--- 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 9f5a98347beedbee8ebb893d288decd13890c941..302d8d3fbd5a633ab7f37c66b4be23129f632201 100644 (file)
--- 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);
+}