thunderbolt: Introduce tb_port_reset()

Introduce a function that issues Downstream Port Reset to a USB4 port.
This supports Thunderbolt 2, 3 and USB4 routers.

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

diff --git a/drivers/thunderbolt/lc.c b/drivers/thunderbolt/lc.c
index 633970fbe9b05904ca4f46876a3561265ed83318..63cb4b6afb718aca9689a01695d9625d83d29d03 100644 (file)
--- a/drivers/thunderbolt/lc.c
+++ b/drivers/thunderbolt/lc.c
@@ -6,6 +6,8 @@
  * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
  */
 
+#include <linux/delay.h>
+
 #include "tb.h"
 
 /**
@@ -45,6 +47,49 @@ static int find_port_lc_cap(struct tb_port *port)
        return sw->cap_lc + start + phys * size;
 }
 
+/**
+ * tb_lc_reset_port() - Trigger downstream port reset through LC
+ * @port: Port that is reset
+ *
+ * Triggers downstream port reset through link controller registers.
+ * Returns %0 in case of success negative errno otherwise. Only supports
+ * non-USB4 routers with link controller (that's Thunderbolt 2 and
+ * Thunderbolt 3).
+ */
+int tb_lc_reset_port(struct tb_port *port)
+{
+       struct tb_switch *sw = port->sw;
+       int cap, ret;
+       u32 mode;
+
+       if (sw->generation < 2)
+               return -EINVAL;
+
+       cap = find_port_lc_cap(port);
+       if (cap < 0)
+               return cap;
+
+       ret = tb_sw_read(sw, &mode, TB_CFG_SWITCH, cap + TB_LC_PORT_MODE, 1);
+       if (ret)
+               return ret;
+
+       mode |= TB_LC_PORT_MODE_DPR;
+
+       ret = tb_sw_write(sw, &mode, TB_CFG_SWITCH, cap + TB_LC_PORT_MODE, 1);
+       if (ret)
+               return ret;
+
+       fsleep(10000);
+
+       ret = tb_sw_read(sw, &mode, TB_CFG_SWITCH, cap + TB_LC_PORT_MODE, 1);
+       if (ret)
+               return ret;
+
+       mode &= ~TB_LC_PORT_MODE_DPR;
+
+       return tb_sw_write(sw, &mode, TB_CFG_SWITCH, cap + TB_LC_PORT_MODE, 1);
+}
+
 static int tb_lc_set_port_configured(struct tb_port *port, bool configured)
 {
        bool upstream = tb_is_upstream_port(port);

diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index 900114ba4371b10fd941e0add6ade8210c74268f..b0e69d4313cea73b5f0e40d9560004e8ee702426 100644 (file)
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -676,6 +676,13 @@ int tb_port_disable(struct tb_port *port)
        return __tb_port_enable(port, false);
 }
 
+static int tb_port_reset(struct tb_port *port)
+{
+       if (tb_switch_is_usb4(port->sw))
+               return port->cap_usb4 ? usb4_port_reset(port) : 0;
+       return tb_lc_reset_port(port);
+}
+
 /*
  * tb_init_port() - initialize a port
  *

diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 997c5a53690524d80445d3106c8836971bd82eff..c38b047ba14beff44ef54bb5759732044fe0c572 100644 (file)
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -1169,6 +1169,7 @@ int tb_drom_read(struct tb_switch *sw);
 int tb_drom_read_uid_only(struct tb_switch *sw, u64 *uid);
 
 int tb_lc_read_uuid(struct tb_switch *sw, u32 *uuid);
+int tb_lc_reset_port(struct tb_port *port);
 int tb_lc_configure_port(struct tb_port *port);
 void tb_lc_unconfigure_port(struct tb_port *port);
 int tb_lc_configure_xdomain(struct tb_port *port);
@@ -1301,6 +1302,7 @@ void usb4_switch_remove_ports(struct tb_switch *sw);
 
 int usb4_port_unlock(struct tb_port *port);
 int usb4_port_hotplug_enable(struct tb_port *port);
+int usb4_port_reset(struct tb_port *port);
 int usb4_port_configure(struct tb_port *port);
 void usb4_port_unconfigure(struct tb_port *port);
 int usb4_port_configure_xdomain(struct tb_port *port, struct tb_xdomain *xd);

diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h
index 87e4795275fe6772e0497e8c50650d4a1835b1af..efcae298b370571c65f9fc0ac9782df9e657ea59 100644 (file)
--- a/drivers/thunderbolt/tb_regs.h
+++ b/drivers/thunderbolt/tb_regs.h
@@ -389,6 +389,7 @@ struct tb_regs_port_header {
 #define PORT_CS_18_CSA                         BIT(22)
 #define PORT_CS_18_TIP                         BIT(24)
 #define PORT_CS_19                             0x13
+#define PORT_CS_19_DPR                         BIT(0)
 #define PORT_CS_19_PC                          BIT(3)
 #define PORT_CS_19_PID                         BIT(4)
 #define PORT_CS_19_WOC                         BIT(16)
@@ -584,6 +585,9 @@ struct tb_regs_hop {
 #define TB_LC_POWER                            0x740
 
 /* Link controller registers */
+#define TB_LC_PORT_MODE                                0x26
+#define TB_LC_PORT_MODE_DPR                    BIT(0)
+
 #define TB_LC_CS_42                            0x2a
 #define TB_LC_CS_42_USB_PLUGGED                        BIT(31)
 

diff --git a/drivers/thunderbolt/usb4.c b/drivers/thunderbolt/usb4.c
index f8f0d24ff6e4629856ea8a59b3941b79633d1781..4b35898aa216697bfe3d4d698efa6ce0beb901d6 100644 (file)
--- a/drivers/thunderbolt/usb4.c
+++ b/drivers/thunderbolt/usb4.c
@@ -1113,6 +1113,45 @@ int usb4_port_hotplug_enable(struct tb_port *port)
        return tb_port_write(port, &val, TB_CFG_PORT, ADP_CS_5, 1);
 }
 
+/**
+ * usb4_port_reset() - Issue downstream port reset
+ * @port: USB4 port to reset
+ *
+ * Issues downstream port reset to @port.
+ */
+int usb4_port_reset(struct tb_port *port)
+{
+       int ret;
+       u32 val;
+
+       if (!port->cap_usb4)
+               return -EINVAL;
+
+       ret = tb_port_read(port, &val, TB_CFG_PORT,
+                          port->cap_usb4 + PORT_CS_19, 1);
+       if (ret)
+               return ret;
+
+       val |= PORT_CS_19_DPR;
+
+       ret = tb_port_write(port, &val, TB_CFG_PORT,
+                           port->cap_usb4 + PORT_CS_19, 1);
+       if (ret)
+               return ret;
+
+       fsleep(10000);
+
+       ret = tb_port_read(port, &val, TB_CFG_PORT,
+                          port->cap_usb4 + PORT_CS_19, 1);
+       if (ret)
+               return ret;
+
+       val &= ~PORT_CS_19_DPR;
+
+       return tb_port_write(port, &val, TB_CFG_PORT,
+                            port->cap_usb4 + PORT_CS_19, 1);
+}
+
 static int usb4_port_set_configured(struct tb_port *port, bool configured)
 {
        int ret;