thunderbolt: Introduce tb_switch_is_icm()

We currently differentiate between SW CM (Software Connection Manager,
sometimes also called External Connection Manager) and ICM (Firmware
based Connection Manager, Internal Connection Manager) by looking
directly at the sw->config.enabled field which may be rather hard to
understand for the casual reader. For this reason introduce a wrapper
function with documentation that should make the intention more clear.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/thunderbolt/lc.c

@@ -94,7 +94,7 @@ int tb_lc_configure_link(struct tb_switch *sw)
 	struct tb_port *up, *down;
 	int ret;
 
-	if (!sw->config.enabled || !tb_route(sw))
+	if (!tb_route(sw) || tb_switch_is_icm(sw))
 		return 0;
 
 	up = tb_upstream_port(sw);
@@ -124,7 +124,7 @@ void tb_lc_unconfigure_link(struct tb_switch *sw)
 {
 	struct tb_port *up, *down;
 
-	if (sw->is_unplugged || !sw->config.enabled || !tb_route(sw))
+	if (sw->is_unplugged || !tb_route(sw) || tb_switch_is_icm(sw))
 		return;
 
 	up = tb_upstream_port(sw);

drivers/thunderbolt/switch.c

@@ -986,7 +986,7 @@ static int tb_plug_events_active(struct tb_switch *sw, bool active)
 	u32 data;
 	int res;
 
-	if (!sw->config.enabled)
+	if (tb_switch_is_icm(sw))
 		return 0;
 
 	sw->config.plug_events_delay = 0xff;
@@ -1720,7 +1720,7 @@ static int tb_switch_add_dma_port(struct tb_switch *sw)
 	}
 
 	/* Root switch DMA port requires running firmware */
-	if (!tb_route(sw) && sw->config.enabled)
+	if (!tb_route(sw) && !tb_switch_is_icm(sw))
 		return 0;
 
 	sw->dma_port = dma_port_alloc(sw);

drivers/thunderbolt/tb.h

@@ -591,6 +591,20 @@ static inline bool tb_switch_is_fr(const struct tb_switch *sw)
 	}
 }
 
+/**
+ * tb_switch_is_icm() - Is the switch handled by ICM firmware
+ * @sw: Switch to check
+ *
+ * In case there is a need to differentiate whether ICM firmware or SW CM
+ * is handling @sw this function can be called. It is valid to call this
+ * after tb_switch_alloc() and tb_switch_configure() has been called
+ * (latter only for SW CM case).
+ */
+static inline bool tb_switch_is_icm(const struct tb_switch *sw)
+{
+	return !sw->config.enabled;
+}
+
 int tb_wait_for_port(struct tb_port *port, bool wait_if_unplugged);
 int tb_port_add_nfc_credits(struct tb_port *port, int credits);
 int tb_port_set_initial_credits(struct tb_port *port, u32 credits);