240 lines
6.8 KiB
Diff
240 lines
6.8 KiB
Diff
From: Andreas Noever <andreas.noever@gmail.com>
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Date: Tue, 3 Jun 2014 22:04:05 +0200
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Subject: [08/31] thunderbolt: Scan for downstream switches
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Origin: https://git.kernel.org/linus/9da672a42878c58af5c50d7389dbae17bea9df38
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Add utility methods tb_port_state and tb_wait_for_port. Add
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tb_scan_switch which recursively checks for downstream switches.
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Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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---
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drivers/thunderbolt/switch.c | 97 ++++++++++++++++++++++++++++++++++++++++++++
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drivers/thunderbolt/tb.c | 44 ++++++++++++++++++++
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drivers/thunderbolt/tb.h | 16 ++++++++
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3 files changed, 157 insertions(+)
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diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
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index 6d193a2..b31b8ce 100644
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--- a/drivers/thunderbolt/switch.c
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+++ b/drivers/thunderbolt/switch.c
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@@ -53,6 +53,92 @@ static void tb_dump_port(struct tb *tb, struct tb_regs_port_header *port)
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}
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/**
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+ * tb_port_state() - get connectedness state of a port
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+ *
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+ * The port must have a TB_CAP_PHY (i.e. it should be a real port).
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+ *
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+ * Return: Returns an enum tb_port_state on success or an error code on failure.
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+ */
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+static int tb_port_state(struct tb_port *port)
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+{
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+ struct tb_cap_phy phy;
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+ int res;
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+ if (port->cap_phy == 0) {
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+ tb_port_WARN(port, "does not have a PHY\n");
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+ return -EINVAL;
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+ }
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+ res = tb_port_read(port, &phy, TB_CFG_PORT, port->cap_phy, 2);
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+ if (res)
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+ return res;
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+ return phy.state;
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+}
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+
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+/**
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+ * tb_wait_for_port() - wait for a port to become ready
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+ *
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+ * Wait up to 1 second for a port to reach state TB_PORT_UP. If
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+ * wait_if_unplugged is set then we also wait if the port is in state
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+ * TB_PORT_UNPLUGGED (it takes a while for the device to be registered after
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+ * switch resume). Otherwise we only wait if a device is registered but the link
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+ * has not yet been established.
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+ *
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+ * Return: Returns an error code on failure. Returns 0 if the port is not
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+ * connected or failed to reach state TB_PORT_UP within one second. Returns 1
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+ * if the port is connected and in state TB_PORT_UP.
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+ */
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+int tb_wait_for_port(struct tb_port *port, bool wait_if_unplugged)
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+{
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+ int retries = 10;
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+ int state;
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+ if (!port->cap_phy) {
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+ tb_port_WARN(port, "does not have PHY\n");
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+ return -EINVAL;
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+ }
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+ if (tb_is_upstream_port(port)) {
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+ tb_port_WARN(port, "is the upstream port\n");
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+ return -EINVAL;
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+ }
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+
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+ while (retries--) {
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+ state = tb_port_state(port);
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+ if (state < 0)
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+ return state;
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+ if (state == TB_PORT_DISABLED) {
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+ tb_port_info(port, "is disabled (state: 0)\n");
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+ return 0;
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+ }
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+ if (state == TB_PORT_UNPLUGGED) {
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+ if (wait_if_unplugged) {
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+ /* used during resume */
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+ tb_port_info(port,
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+ "is unplugged (state: 7), retrying...\n");
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+ msleep(100);
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+ continue;
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+ }
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+ tb_port_info(port, "is unplugged (state: 7)\n");
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+ return 0;
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+ }
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+ if (state == TB_PORT_UP) {
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+ tb_port_info(port,
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+ "is connected, link is up (state: 2)\n");
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+ return 1;
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+ }
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+
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+ /*
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+ * After plug-in the state is TB_PORT_CONNECTING. Give it some
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+ * time.
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+ */
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+ tb_port_info(port,
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+ "is connected, link is not up (state: %d), retrying...\n",
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+ state);
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+ msleep(100);
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+ }
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+ tb_port_warn(port,
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+ "failed to reach state TB_PORT_UP. Ignoring port...\n");
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+ return 0;
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+}
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+
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+/**
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* tb_init_port() - initialize a port
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*
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* This is a helper method for tb_switch_alloc. Does not check or initialize
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@@ -63,6 +149,7 @@ static void tb_dump_port(struct tb *tb, struct tb_regs_port_header *port)
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static int tb_init_port(struct tb_switch *sw, u8 port_nr)
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{
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int res;
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+ int cap;
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struct tb_port *port = &sw->ports[port_nr];
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port->sw = sw;
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port->port = port_nr;
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@@ -71,6 +158,16 @@ static int tb_init_port(struct tb_switch *sw, u8 port_nr)
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if (res)
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return res;
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+ /* Port 0 is the switch itself and has no PHY. */
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+ if (port->config.type == TB_TYPE_PORT && port_nr != 0) {
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+ cap = tb_find_cap(port, TB_CFG_PORT, TB_CAP_PHY);
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+
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+ if (cap > 0)
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+ port->cap_phy = cap;
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+ else
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+ tb_port_WARN(port, "non switch port without a PHY\n");
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+ }
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+
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tb_dump_port(sw->tb, &port->config);
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/* TODO: Read dual link port, DP port and more from EEPROM. */
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diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
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index f1b6100..3b716fd 100644
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--- a/drivers/thunderbolt/tb.c
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+++ b/drivers/thunderbolt/tb.c
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@@ -11,6 +11,47 @@
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#include "tb.h"
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#include "tb_regs.h"
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+
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+/* enumeration & hot plug handling */
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+
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+
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+static void tb_scan_port(struct tb_port *port);
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+
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+/**
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+ * tb_scan_switch() - scan for and initialize downstream switches
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+ */
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+static void tb_scan_switch(struct tb_switch *sw)
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+{
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+ int i;
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+ for (i = 1; i <= sw->config.max_port_number; i++)
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+ tb_scan_port(&sw->ports[i]);
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+}
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+
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+/**
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+ * tb_scan_port() - check for and initialize switches below port
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+ */
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+static void tb_scan_port(struct tb_port *port)
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+{
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+ struct tb_switch *sw;
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+ if (tb_is_upstream_port(port))
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+ return;
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+ if (port->config.type != TB_TYPE_PORT)
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+ return;
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+ if (tb_wait_for_port(port, false) <= 0)
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+ return;
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+ if (port->remote) {
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+ tb_port_WARN(port, "port already has a remote!\n");
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+ return;
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+ }
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+ sw = tb_switch_alloc(port->sw->tb, tb_downstream_route(port));
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+ if (!sw)
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+ return;
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+ port->remote = tb_upstream_port(sw);
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+ tb_upstream_port(sw)->remote = port;
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+ tb_scan_switch(sw);
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+}
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+
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+
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/* hotplug handling */
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struct tb_hotplug_event {
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@@ -134,6 +175,9 @@ struct tb *thunderbolt_alloc_and_start(struct tb_nhi *nhi)
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if (!tb->root_switch)
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goto err_locked;
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+ /* Full scan to discover devices added before the driver was loaded. */
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+ tb_scan_switch(tb->root_switch);
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+
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/* Allow tb_handle_hotplug to progress events */
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tb->hotplug_active = true;
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mutex_unlock(&tb->lock);
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diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
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index af123c4..70a66fe 100644
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--- a/drivers/thunderbolt/tb.h
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+++ b/drivers/thunderbolt/tb.h
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@@ -29,6 +29,7 @@ struct tb_port {
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struct tb_regs_port_header config;
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struct tb_switch *sw;
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struct tb_port *remote; /* remote port, NULL if not connected */
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+ int cap_phy; /* offset, zero if not found */
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u8 port; /* port number on switch */
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};
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@@ -160,6 +161,8 @@ void thunderbolt_shutdown_and_free(struct tb *tb);
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struct tb_switch *tb_switch_alloc(struct tb *tb, u64 route);
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void tb_switch_free(struct tb_switch *sw);
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+int tb_wait_for_port(struct tb_port *port, bool wait_if_unplugged);
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+
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int tb_find_cap(struct tb_port *port, enum tb_cfg_space space, u32 value);
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@@ -173,4 +176,17 @@ static inline bool tb_is_upstream_port(struct tb_port *port)
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return port == tb_upstream_port(port->sw);
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}
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+/**
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+ * tb_downstream_route() - get route to downstream switch
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+ *
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+ * Port must not be the upstream port (otherwise a loop is created).
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+ *
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+ * Return: Returns a route to the switch behind @port.
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+ */
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+static inline u64 tb_downstream_route(struct tb_port *port)
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+{
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+ return tb_route(port->sw)
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+ | ((u64) port->port << (port->sw->config.depth * 8));
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+}
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+
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#endif
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