thunderbolt: Scan for downstream switches
Add utility methods tb_port_state and tb_wait_for_port. Add
tb_scan_switch which recursively checks for downstream switches.
Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index 6d193a2..b31b8ce 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -53,6 +53,92 @@
}
/**
+ * tb_port_state() - get connectedness state of a port
+ *
+ * The port must have a TB_CAP_PHY (i.e. it should be a real port).
+ *
+ * Return: Returns an enum tb_port_state on success or an error code on failure.
+ */
+static int tb_port_state(struct tb_port *port)
+{
+ struct tb_cap_phy phy;
+ int res;
+ if (port->cap_phy == 0) {
+ tb_port_WARN(port, "does not have a PHY\n");
+ return -EINVAL;
+ }
+ res = tb_port_read(port, &phy, TB_CFG_PORT, port->cap_phy, 2);
+ if (res)
+ return res;
+ return phy.state;
+}
+
+/**
+ * tb_wait_for_port() - wait for a port to become ready
+ *
+ * Wait up to 1 second for a port to reach state TB_PORT_UP. If
+ * wait_if_unplugged is set then we also wait if the port is in state
+ * TB_PORT_UNPLUGGED (it takes a while for the device to be registered after
+ * switch resume). Otherwise we only wait if a device is registered but the link
+ * has not yet been established.
+ *
+ * Return: Returns an error code on failure. Returns 0 if the port is not
+ * connected or failed to reach state TB_PORT_UP within one second. Returns 1
+ * if the port is connected and in state TB_PORT_UP.
+ */
+int tb_wait_for_port(struct tb_port *port, bool wait_if_unplugged)
+{
+ int retries = 10;
+ int state;
+ if (!port->cap_phy) {
+ tb_port_WARN(port, "does not have PHY\n");
+ return -EINVAL;
+ }
+ if (tb_is_upstream_port(port)) {
+ tb_port_WARN(port, "is the upstream port\n");
+ return -EINVAL;
+ }
+
+ while (retries--) {
+ state = tb_port_state(port);
+ if (state < 0)
+ return state;
+ if (state == TB_PORT_DISABLED) {
+ tb_port_info(port, "is disabled (state: 0)\n");
+ return 0;
+ }
+ if (state == TB_PORT_UNPLUGGED) {
+ if (wait_if_unplugged) {
+ /* used during resume */
+ tb_port_info(port,
+ "is unplugged (state: 7), retrying...\n");
+ msleep(100);
+ continue;
+ }
+ tb_port_info(port, "is unplugged (state: 7)\n");
+ return 0;
+ }
+ if (state == TB_PORT_UP) {
+ tb_port_info(port,
+ "is connected, link is up (state: 2)\n");
+ return 1;
+ }
+
+ /*
+ * After plug-in the state is TB_PORT_CONNECTING. Give it some
+ * time.
+ */
+ tb_port_info(port,
+ "is connected, link is not up (state: %d), retrying...\n",
+ state);
+ msleep(100);
+ }
+ tb_port_warn(port,
+ "failed to reach state TB_PORT_UP. Ignoring port...\n");
+ return 0;
+}
+
+/**
* tb_init_port() - initialize a port
*
* This is a helper method for tb_switch_alloc. Does not check or initialize
@@ -63,6 +149,7 @@
static int tb_init_port(struct tb_switch *sw, u8 port_nr)
{
int res;
+ int cap;
struct tb_port *port = &sw->ports[port_nr];
port->sw = sw;
port->port = port_nr;
@@ -71,6 +158,16 @@
if (res)
return res;
+ /* Port 0 is the switch itself and has no PHY. */
+ if (port->config.type == TB_TYPE_PORT && port_nr != 0) {
+ cap = tb_find_cap(port, TB_CFG_PORT, TB_CAP_PHY);
+
+ if (cap > 0)
+ port->cap_phy = cap;
+ else
+ tb_port_WARN(port, "non switch port without a PHY\n");
+ }
+
tb_dump_port(sw->tb, &port->config);
/* TODO: Read dual link port, DP port and more from EEPROM. */