5 files changed, 37 insertions, 12 deletions

diff --git a/drivers/thunderbolt/Makefile b/drivers/thunderbolt/Makefile
index f2f0de27252b..8531f15d3b3c 100644
--- a/drivers/thunderbolt/Makefile
+++ b/drivers/thunderbolt/Makefile
@@ -1,3 +1,3 @@
 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
diff --git a/drivers/thunderbolt/lc.c b/drivers/thunderbolt/lc.c
new file mode 100644
index 000000000000..2134a55ed837
--- /dev/null
+++ b/drivers/thunderbolt/lc.c
@@ -0,0 +1,21 @@
+// 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);
+}
diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index 1e29c06947af..63ff4c753d89 100644
--- a/drivers/thunderbolt/switch.c
+++ b/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)
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index a166265dfcf9..e52d39b25266 100644
--- a/drivers/thunderbolt/tb.h
+++ b/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)
 {
diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h
index 6f1ff04ee195..4895ae9f0b40 100644
--- a/drivers/thunderbolt/tb_regs.h
+++ b/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