[PATCH 6/8] thunderbolt: Verify Router Ready bit is set after router enumeration

[Mika Westerberg <mika.westerberg@linux.intel.com>]

From: Gil Fine <gil.fine@linux.intel.com>

The USB4 Connection Manager guide specifies that after enumerating a
router, the Connection Manager shall verify that the Router Ready bit
(ROUTER_CS_6.RR) has been set to ensure hardware configuration has completed.
Currently, this step is missing from the enumeration sequence.

Add this check to follow the Connection Manager guide more closely.

Signed-off-by: Gil Fine <gil.fine@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/thunderbolt/tb_regs.h | 1 +
 drivers/thunderbolt/usb4.c    | 7 ++++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h
index 75131fcfe044..69ca4c379cc9 100644
--- a/drivers/thunderbolt/tb_regs.h
+++ b/drivers/thunderbolt/tb_regs.h
@@ -216,6 +216,7 @@ struct tb_regs_switch_header {
 #define ROUTER_CS_6_WOPS			BIT(2)
 #define ROUTER_CS_6_WOUS			BIT(3)
 #define ROUTER_CS_6_HCI				BIT(18)
+#define ROUTER_CS_6_RR				BIT(24)
 #define ROUTER_CS_6_CR				BIT(25)
 #define ROUTER_CS_7				0x07
 #define ROUTER_CS_9				0x09
diff --git a/drivers/thunderbolt/usb4.c b/drivers/thunderbolt/usb4.c
index 6f76bcaefa49..54f4f5fa3c5a 100644
--- a/drivers/thunderbolt/usb4.c
+++ b/drivers/thunderbolt/usb4.c
@@ -294,7 +294,12 @@ int usb4_switch_setup(struct tb_switch *sw)
 	/* TBT3 supported by the CM */
 	val &= ~ROUTER_CS_5_CNS;
 
-	return tb_sw_write(sw, &val, TB_CFG_SWITCH, ROUTER_CS_5, 1);
+	ret = tb_sw_write(sw, &val, TB_CFG_SWITCH, ROUTER_CS_5, 1);
+	if (ret)
+		return ret;
+
+	return tb_switch_wait_for_bit(sw, ROUTER_CS_6, ROUTER_CS_6_RR,
+				      ROUTER_CS_6_RR, 500);
 }
 
 /**
-- 
2.50.1