usb: typec: Only attempt to link USB ports if there is fwnode

The code that creates the links to the USB ports attached to
a connector inside the system assumed that the ACPI nodes
(fwnodes) always exist for the connectors, but it can not do
that.

There is no guarantee that every USB Type-C connector has
ACPI device node representing it in the ACPI tables, and
even if there are the nodes in the ACPI tables, the _STA
method in those nodes may still return 0 (which means the
device does not exist from ACPI PoW).

This fixes NULL pointer dereference that happens if the
nodes are missing.

Fixes: 730b49aac426 ("usb: typec: port-mapper: Convert to the component framework")
Reported-and-tested-by: Robert Święcki <robert@swiecki.net>
Reported-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20220124090228.41396-2-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/port-mapper.c b/drivers/usb/typec/port-mapper.c
index 07d3074..b6e0c6a 100644 (file)
--- a/drivers/usb/typec/port-mapper.c
+++ b/drivers/usb/typec/port-mapper.c
@@ -56,6 +56,9 @@ int typec_link_ports(struct typec_port *con)
 {
        struct each_port_arg arg = { .port = con, .match = NULL };
 
+       if (!has_acpi_companion(&con->dev))
+               return 0;
+
        bus_for_each_dev(&acpi_bus_type, NULL, &arg, typec_port_match);
 
        /*
@@ -74,5 +77,6 @@ int typec_link_ports(struct typec_port *con)
 
 void typec_unlink_ports(struct typec_port *con)
 {
-       component_master_del(&con->dev, &typec_aggregate_ops);
+       if (has_acpi_companion(&con->dev))
+               component_master_del(&con->dev, &typec_aggregate_ops);
 }