[U-Boot] [PATCH 3/5] dm: usb: Do not scan companion busses if no devices where handed over

[Hans de Goede]

USB scanning is slow, and there is no need to scan the companion busses
if no usb devices where handed over to the companinon controllers by any
of the main controllers.

This saves e.g. 2 seconds when booting a A10 OLinuxIno Lime with no USB-1
devices plugged into the root usb ports.

The use of a global variable for the companion handover counting is somewhat
unfortunate, but we do not have the necessary info to link companions and
main controllers together in devicetree, and since this is just an
optimization adding a custom devicetree extenstion for this seems undesirable.

Signed-off-by: Hans de Goede <hdegoede at redhat.com>
---
 common/usb.c                  |  2 ++
 drivers/usb/host/usb-uclass.c | 12 +++++++-----
 include/usb.h                 |  3 +++
 3 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/common/usb.c b/common/usb.c
index 1b26bfa..4a09583 100644
--- a/common/usb.c
+++ b/common/usb.c
@@ -44,6 +44,8 @@
 
 static int asynch_allowed;
 char usb_started; /* flag for the started/stopped USB status */
+/* Tracks how much devices were handed over to companion controllers */
+int usb_companion_device_count;
 
 #ifndef CONFIG_DM_USB
 static struct usb_device usb_dev[USB_MAX_DEVICE];
diff --git a/drivers/usb/host/usb-uclass.c b/drivers/usb/host/usb-uclass.c
index d745c1c..877d307 100644
--- a/drivers/usb/host/usb-uclass.c
+++ b/drivers/usb/host/usb-uclass.c
@@ -219,12 +219,14 @@ int usb_init(void)
 	/*
 	 * Now that the primary controllers have been scanned and have handed
 	 * over any devices they do not understand to their companions, scan
-	 * the companions.
+	 * the companions if necessary.
 	 */
-	uclass_foreach_dev(bus, uc) {
-		priv = dev_get_uclass_priv(bus);
-		if (priv->companion)
-			usb_scan_bus(bus, true);
+	if (usb_companion_device_count) {
+		uclass_foreach_dev(bus, uc) {
+			priv = dev_get_uclass_priv(bus);
+			if (priv->companion)
+				usb_scan_bus(bus, true);
+		}
 	}
 
 	debug("scan end\n");
diff --git a/include/usb.h b/include/usb.h
index b81e796..d4c9f44 100644
--- a/include/usb.h
+++ b/include/usb.h
@@ -171,6 +171,9 @@ enum usb_init_type {
  * this is how the lowlevel part communicate with the outer world
  */
 
+/* Tracks how much devices were handed over to companion controllers */
+extern int usb_companion_device_count;
+
 #if defined(CONFIG_USB_UHCI) || defined(CONFIG_USB_OHCI) || \
 	defined(CONFIG_USB_EHCI) || defined(CONFIG_USB_OHCI_NEW) || \
 	defined(CONFIG_USB_SL811HS) || defined(CONFIG_USB_ISP116X_HCD) || \
-- 
2.3.6