thunderbolt: Constify the struct device_type usage

Since commit aed65af1 ("drivers: make device_type const"), the driver
core can properly handle constant struct device_type. Move the
tb_domain_type, tb_retimer_type, tb_switch_type, usb4_port_device_type,
tb_service_type and tb_xdomain_type variables to be constant structures as
well, placing it into read-only memory which can not be modified at
runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/thunderbolt/domain.c

@@ -326,7 +326,7 @@ static void tb_domain_release(struct device *dev)
 	kfree(tb);
 }
 
-struct device_type tb_domain_type = {
+const struct device_type tb_domain_type = {
 	.name = "thunderbolt_domain",
 	.release = tb_domain_release,
 };

drivers/thunderbolt/retimer.c

@@ -356,7 +356,7 @@ static void tb_retimer_release(struct device *dev)
 	kfree(rt);
 }
 
-struct device_type tb_retimer_type = {
+const struct device_type tb_retimer_type = {
 	.name = "thunderbolt_retimer",
 	.groups = retimer_groups,
 	.release = tb_retimer_release,

drivers/thunderbolt/switch.c

@@ -2327,7 +2327,7 @@ static const struct dev_pm_ops tb_switch_pm_ops = {
 			   NULL)
 };
 
-struct device_type tb_switch_type = {
+const struct device_type tb_switch_type = {
 	.name = "thunderbolt_device",
 	.release = tb_switch_release,
 	.uevent = tb_switch_uevent,

drivers/thunderbolt/tb.h

@@ -749,10 +749,10 @@ static inline int tb_port_write(struct tb_port *port, const void *buffer,
 struct tb *icm_probe(struct tb_nhi *nhi);
 struct tb *tb_probe(struct tb_nhi *nhi);
 
-extern struct device_type tb_domain_type;
-extern struct device_type tb_retimer_type;
-extern struct device_type tb_switch_type;
-extern struct device_type usb4_port_device_type;
+extern const struct device_type tb_domain_type;
+extern const struct device_type tb_retimer_type;
+extern const struct device_type tb_switch_type;
+extern const struct device_type usb4_port_device_type;
 
 int tb_domain_init(void);
 void tb_domain_exit(void);

drivers/thunderbolt/usb4_port.c

@@ -243,7 +243,7 @@ static void usb4_port_device_release(struct device *dev)
 	kfree(usb4);
 }
 
-struct device_type usb4_port_device_type = {
+const struct device_type usb4_port_device_type = {
 	.name = "usb4_port",
 	.groups = usb4_port_device_groups,
 	.release = usb4_port_device_release,

drivers/thunderbolt/xdomain.c

@@ -1002,7 +1002,7 @@ static void tb_service_release(struct device *dev)
 	kfree(svc);
 }
 
-struct device_type tb_service_type = {
+const struct device_type tb_service_type = {
 	.name = "thunderbolt_service",
 	.groups = tb_service_attr_groups,
 	.uevent = tb_service_uevent,
@@ -1893,7 +1893,7 @@ static const struct dev_pm_ops tb_xdomain_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(tb_xdomain_suspend, tb_xdomain_resume)
 };
 
-struct device_type tb_xdomain_type = {
+const struct device_type tb_xdomain_type = {
 	.name = "thunderbolt_xdomain",
 	.release = tb_xdomain_release,
 	.pm = &tb_xdomain_pm_ops,

include/linux/thunderbolt.h

@@ -87,8 +87,8 @@ struct tb {
 };
 
 extern const struct bus_type tb_bus_type;
-extern struct device_type tb_service_type;
-extern struct device_type tb_xdomain_type;
+extern const struct device_type tb_service_type;
+extern const struct device_type tb_xdomain_type;
 
 #define TB_LINKS_PER_PHY_PORT	2