thunderbolt: Move LC specific functionality into a separate file

We will be adding more link controller functionality in subsequent
patches and it does not make sense to keep all that in switch.c, so
separate LC functionality into its own file.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/thunderbolt/Makefile

 obj-${CONFIG_THUNDERBOLT} := thunderbolt.o
 thunderbolt-objs := nhi.o ctl.o tb.o switch.o cap.o path.o tunnel_pci.o eeprom.o
-thunderbolt-objs += domain.o dma_port.o icm.o property.o xdomain.o
+thunderbolt-objs += domain.o dma_port.o icm.o property.o xdomain.o lc.o

drivers/thunderbolt/lc.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Thunderbolt link controller support
+ *
+ * Copyright (C) 2019, Intel Corporation
+ * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
+ */
+
+#include "tb.h"
+
+/**
+ * tb_lc_read_uuid() - Read switch UUID from link controller common register
+ * @sw: Switch whose UUID is read
+ * @uuid: UUID is placed here
+ */
+int tb_lc_read_uuid(struct tb_switch *sw, u32 *uuid)
+{
+	if (!sw->cap_lc)
+		return -EINVAL;
+	return tb_sw_read(sw, uuid, TB_CFG_SWITCH, sw->cap_lc + TB_LC_FUSE, 4);
+}

drivers/thunderbolt/switch.c

@@ -1182,6 +1182,10 @@ struct tb_switch *tb_switch_alloc(struct tb *tb, struct device *parent,
 	}
 	sw->cap_plug_events = cap;
 
+	cap = tb_switch_find_vse_cap(sw, TB_VSE_CAP_LINK_CONTROLLER);
+	if (cap > 0)
+		sw->cap_lc = cap;
+
 	/* Root switch is always authorized */
 	if (!route)
 		sw->authorized = true;
@@ -1278,22 +1282,17 @@ int tb_switch_configure(struct tb_switch *sw)
 static int tb_switch_set_uuid(struct tb_switch *sw)
 {
 	u32 uuid[4];
-	int cap, ret;
+	int ret;
 
-	ret = 0;
 	if (sw->uuid)
-		return ret;
+		return 0;
 
 	/*
 	 * The newer controllers include fused UUID as part of link
 	 * controller specific registers
 	 */
-	cap = tb_switch_find_vse_cap(sw, TB_VSE_CAP_LINK_CONTROLLER);
-	if (cap > 0) {
-		ret = tb_sw_read(sw, uuid, TB_CFG_SWITCH, cap + 3, 4);
-		if (ret)
-			return ret;
-	} else {
+	ret = tb_lc_read_uuid(sw, uuid);
+	if (ret) {
 		/*
 		 * ICM generates UUID based on UID and fills the upper
 		 * two words with ones. This is not strictly following
@@ -1308,8 +1307,8 @@ static int tb_switch_set_uuid(struct tb_switch *sw)
 
 	sw->uuid = kmemdup(uuid, sizeof(uuid), GFP_KERNEL);
 	if (!sw->uuid)
-		ret = -ENOMEM;
-	return ret;
+		return -ENOMEM;
+	return 0;
 }
 
 static int tb_switch_add_dma_port(struct tb_switch *sw)

drivers/thunderbolt/tb.h

@@ -63,6 +63,7 @@ struct tb_switch_nvm {
  * @device_name: Name of the device (or %NULL if not known)
  * @generation: Switch Thunderbolt generation
  * @cap_plug_events: Offset to the plug events capability (%0 if not found)
+ * @cap_lc: Offset to the link controller capability (%0 if not found)
  * @is_unplugged: The switch is going away
  * @drom: DROM of the switch (%NULL if not found)
  * @nvm: Pointer to the NVM if the switch has one (%NULL otherwise)
@@ -96,6 +97,7 @@ struct tb_switch {
 	const char *device_name;
 	unsigned int generation;
 	int cap_plug_events;
+	int cap_lc;
 	bool is_unplugged;
 	u8 *drom;
 	struct tb_switch_nvm *nvm;
@@ -462,6 +464,7 @@ bool tb_path_is_invalid(struct tb_path *path);
 int tb_drom_read(struct tb_switch *sw);
 int tb_drom_read_uid_only(struct tb_switch *sw, u64 *uid);
 
+int tb_lc_read_uuid(struct tb_switch *sw, u32 *uuid);
 
 static inline int tb_route_length(u64 route)
 {

drivers/thunderbolt/tb_regs.h

@@ -237,5 +237,7 @@ struct tb_regs_hop {
 	u32 unknown3:4; /* set to zero */
 } __packed;
 
+/* Common link controller registers */
+#define TB_LC_FUSE			0x03
 
 #endif