[PATCH 6.6 075/158] thunderbolt: Introduce tb_port_reset()

Greg Kroah-Hartman
2024-04-23T21:43:39Z

From: Sanath S <Sanath.S@amd.com>

commit 01da6b99d49f60b1edead44e33569b1a2e9f49b7 upstream.

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>
Cc: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/thunderbolt/lc.c | 45 ++++++++++++++++++++++++++++++++++++++++++
drivers/thunderbolt/switch.c | 7 ++++++
drivers/thunderbolt/tb.h | 2 +
drivers/thunderbolt/tb_regs.h | 4 +++
drivers/thunderbolt/usb4.c | 39 ++++++++++++++++++++++++++++++++++++
5 files changed, 97 insertions(+)

--- 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_po
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);
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -675,6 +675,13 @@ 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
*
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -1119,6 +1119,7 @@ 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);
@@ -1251,6 +1252,7 @@ void usb4_switch_remove_ports(struct tb_

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);
--- a/drivers/thunderbolt/tb_regs.h
+++ b/drivers/thunderbolt/tb_regs.h
@@ -383,6 +383,7 @@ struct tb_regs_port_header {
#define PORT_CS_18_WODS BIT(17)
#define PORT_CS_18_WOU4S BIT(18)
#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)
@@ -579,6 +580,9 @@ 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)

--- a/drivers/thunderbolt/usb4.c
+++ b/drivers/thunderbolt/usb4.c
@@ -1113,6 +1113,45 @@ int usb4_port_hotplug_enable(struct tb_p
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;