usb: typec: thunderbolt: Set enter_vdo during initialization

In the current implementation, if a cable's alternate mode enter operation
is not supported, the tbt->plug[TYPEC_PLUG_SOP_P] pointer is cleared by the
time tbt_enter_mode() is called. This prevents the driver from identifying
the cable's VDO.

As a result, the Thunderbolt connection falls back to the default
TBT_CABLE_USB3_PASSIVE speed, even if the cable supports higher speeds.
To ensure the correct VDO value is used during mode entry, calculate and
store the enter_vdo earlier during the initialization phase in tbt_ready().

Cc: stable <stable@kernel.org>
Fixes: 100e257 ("usb: typec: Add driver for Thunderbolt 3 Alternate Mode")
Tested-by: Madhu M <madhu.m@intel.corp-partner.google.com>
Signed-off-by: Andrei Kuchynski <akuchynski@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Benson Leung <bleung@chromium.org>
Link: https://patch.msgid.link/20260324103012.1417616-1-akuchynski@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Andrei Kuchynski

drivers/usb/typec/altmodes/thunderbolt.c

@@ -39,28 +39,7 @@ static bool tbt_ready(struct typec_altmode *alt);
 
 static int tbt_enter_mode(struct tbt_altmode *tbt)
 {
-	struct typec_altmode *plug = tbt->plug[TYPEC_PLUG_SOP_P];
-	u32 vdo;
-
-	vdo = tbt->alt->vdo & (TBT_VENDOR_SPECIFIC_B0 | TBT_VENDOR_SPECIFIC_B1);
-	vdo |= tbt->alt->vdo & TBT_INTEL_SPECIFIC_B0;
-	vdo |= TBT_MODE;
-
-	if (plug) {
-		if (typec_cable_is_active(tbt->cable))
-			vdo |= TBT_ENTER_MODE_ACTIVE_CABLE;
-
-		vdo |= TBT_ENTER_MODE_CABLE_SPEED(TBT_CABLE_SPEED(plug->vdo));
-		vdo |= plug->vdo & TBT_CABLE_ROUNDED;
-		vdo |= plug->vdo & TBT_CABLE_OPTICAL;
-		vdo |= plug->vdo & TBT_CABLE_RETIMER;
-		vdo |= plug->vdo & TBT_CABLE_LINK_TRAINING;
-	} else {
-		vdo |= TBT_ENTER_MODE_CABLE_SPEED(TBT_CABLE_USB3_PASSIVE);
-	}
-
-	tbt->enter_vdo = vdo;
-	return typec_altmode_enter(tbt->alt, &vdo);
+	return typec_altmode_enter(tbt->alt, &tbt->enter_vdo);
 }
 
 static void tbt_altmode_work(struct work_struct *work)
@@ -337,6 +316,7 @@ static bool tbt_ready(struct typec_altmode *alt)
 {
 	struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
 	struct typec_altmode *plug;
+	u32 vdo;
 
 	if (tbt->cable)
 		return true;
@@ -364,6 +344,26 @@ static bool tbt_ready(struct typec_altmode *alt)
 		tbt->plug[i] = plug;
 	}
 
+	vdo = tbt->alt->vdo & (TBT_VENDOR_SPECIFIC_B0 | TBT_VENDOR_SPECIFIC_B1);
+	vdo |= tbt->alt->vdo & TBT_INTEL_SPECIFIC_B0;
+	vdo |= TBT_MODE;
+	plug = tbt->plug[TYPEC_PLUG_SOP_P];
+
+	if (plug) {
+		if (typec_cable_is_active(tbt->cable))
+			vdo |= TBT_ENTER_MODE_ACTIVE_CABLE;
+
+		vdo |= TBT_ENTER_MODE_CABLE_SPEED(TBT_CABLE_SPEED(plug->vdo));
+		vdo |= plug->vdo & TBT_CABLE_ROUNDED;
+		vdo |= plug->vdo & TBT_CABLE_OPTICAL;
+		vdo |= plug->vdo & TBT_CABLE_RETIMER;
+		vdo |= plug->vdo & TBT_CABLE_LINK_TRAINING;
+	} else {
+		vdo |= TBT_ENTER_MODE_CABLE_SPEED(TBT_CABLE_USB3_PASSIVE);
+	}
+
+	tbt->enter_vdo = vdo;
+
 	return true;
 }