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Subject[PATCH v2 09/14] thunderbolt: Handle hotplug events
Date
We reveive a plug event callback whenever a thunderbolt device is added
or removed. This patch fills in the tb_handle_hotplug method and starts
reacting to these events by adding/removing switches from the hierarchy.

Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
---
drivers/thunderbolt/switch.c | 42 +++++++++++++++++++++++++++++++++++++++-
drivers/thunderbolt/tb.c | 46 +++++++++++++++++++++++++++++++++++++++++++-
drivers/thunderbolt/tb.h | 3 +++
3 files changed, 89 insertions(+), 2 deletions(-)

diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index 279b9c5..c092f7c 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -195,6 +195,24 @@ static void tb_dump_switch(struct tb *tb, struct tb_regs_switch_header *sw)
sw->__unknown1, sw->__unknown4);
}

+struct tb_switch *get_switch_at_route(struct tb_switch *sw, u64 route)
+{
+ u8 next_port = route; /*
+ * Routes use a stride of 8 bits,
+ * eventhough a port index has 6 bits at most.
+ * */
+ if (route == 0)
+ return sw;
+ if (next_port > sw->config.max_port_number)
+ return 0;
+ if (tb_is_upstream_port(&sw->ports[next_port]))
+ return 0;
+ if (!sw->ports[next_port].remote)
+ return 0;
+ return get_switch_at_route(sw->ports[next_port].remote->sw,
+ route >> TB_ROUTE_SHIFT);
+}
+
/**
* tb_plug_events_active() - enable/disable plug events on a switch
*
@@ -243,7 +261,8 @@ void tb_switch_free(struct tb_switch *sw)
sw->ports[i].remote = NULL;
}

- tb_plug_events_active(sw, false);
+ if (!sw->is_unplugged)
+ tb_plug_events_active(sw, false);

kfree(sw->ports);
kfree(sw);
@@ -327,3 +346,24 @@ err:
return NULL;
}

+/**
+ * tb_sw_set_unpplugged() - set is_unplugged on switch and downstream switches
+ */
+void tb_sw_set_unpplugged(struct tb_switch *sw)
+{
+ int i;
+ if (sw == sw->tb->root_switch) {
+ tb_sw_WARN(sw, "cannot unplug root switch\n");
+ return;
+ }
+ if (sw->is_unplugged) {
+ tb_sw_WARN(sw, "is_unplugged already set\n");
+ return;
+ }
+ sw->is_unplugged = true;
+ for (i = 0; i <= sw->config.max_port_number; i++) {
+ if (!tb_is_upstream_port(&sw->ports[i]) && sw->ports[i].remote)
+ tb_sw_set_unpplugged(sw->ports[i].remote->sw);
+ }
+}
+
diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
index 3b716fd..1efcacc 100644
--- a/drivers/thunderbolt/tb.c
+++ b/drivers/thunderbolt/tb.c
@@ -71,11 +71,55 @@ static void tb_handle_hotplug(struct work_struct *work)
{
struct tb_hotplug_event *ev = container_of(work, typeof(*ev), work);
struct tb *tb = ev->tb;
+ struct tb_switch *sw;
+ struct tb_port *port;
mutex_lock(&tb->lock);
if (!tb->hotplug_active)
goto out; /* during init, suspend or shutdown */

- /* do nothing for now */
+ sw = get_switch_at_route(tb->root_switch, ev->route);
+ if (!sw) {
+ tb_warn(tb,
+ "hotplug event from non existent switch %llx:%x (unplug: %d)\n",
+ ev->route, ev->port, ev->unplug);
+ goto out;
+ }
+ if (ev->port > sw->config.max_port_number) {
+ tb_warn(tb,
+ "hotplug event from non existent port %llx:%x (unplug: %d)\n",
+ ev->route, ev->port, ev->unplug);
+ goto out;
+ }
+ port = &sw->ports[ev->port];
+ if (tb_is_upstream_port(port)) {
+ tb_warn(tb,
+ "hotplug event for upstream port %llx:%x (unplug: %d)\n",
+ ev->route, ev->port, ev->unplug);
+ goto out;
+ }
+ if (ev->unplug) {
+ if (port->remote) {
+ tb_port_info(port, "unplugged\n");
+ tb_sw_set_unpplugged(port->remote->sw);
+ tb_switch_free(port->remote->sw);
+ port->remote = NULL;
+ } else {
+ tb_port_info(port,
+ "got unplug event for disconnected port, ignoring\n");
+ }
+ } else if (port->remote) {
+ tb_port_info(port,
+ "got plug event for connected port, ignoring\n");
+ } else {
+ tb_port_info(port, "hotplug: scanning\n");
+ tb_scan_port(port);
+ if (!port->remote) {
+ tb_port_info(port, "hotplug: no switch found\n");
+ } else if (port->remote->sw->config.depth > 1) {
+ tb_sw_warn(port->remote->sw,
+ "hotplug: chaining not supported\n");
+ }
+ }
out:
mutex_unlock(&tb->lock);
kfree(ev);
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 7e7b3fe..3b83510 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -20,6 +20,7 @@ struct tb_switch {
struct tb_port *ports;
struct tb *tb;
int cap_plug_events; /* offset, zero if not found */
+ bool is_unplugged; /* unplugged, will go away */
};

/**
@@ -160,6 +161,8 @@ void thunderbolt_shutdown_and_free(struct tb *tb);

struct tb_switch *tb_switch_alloc(struct tb *tb, u64 route);
void tb_switch_free(struct tb_switch *sw);
+void tb_sw_set_unpplugged(struct tb_switch *sw);
+struct tb_switch *get_switch_at_route(struct tb_switch *sw, u64 route);

int tb_wait_for_port(struct tb_port *port, bool wait_if_unplugged);

--
1.9.2


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