From: Vivek Gautam <gautam.vivek@samsung.com>
Date: Wed, 24 Apr 2013 02:50:11 +0000 (+0000)
Subject: usb: hub: Parallelize power-cycling of root-hub ports
X-Git-Tag: v2013.07-rc1~1^2~74
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=0bf796f7ae22086f0504f3297e9fb4e96aa04161;p=kernel%2Fu-boot.git

usb: hub: Parallelize power-cycling of root-hub ports

Untill now we power-cycle (aka: disable power on a port
and re-enabling again) one port at a time.
Delay of 20ms for Port-power to change multiplies with
number of ports in this case.
So better we parallelize this process:
disable power on all ports, wait for port-power to stabilize
and then re-enable the power subsequently.

Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
---

diff --git a/common/usb_hub.c b/common/usb_hub.c
index 1e225e6..4fbfacf 100644
--- a/common/usb_hub.c
+++ b/common/usb_hub.c
@@ -105,19 +105,22 @@ static void usb_hub_power_on(struct usb_hub_device *hub)
 	int ret;
 
 	dev = hub->pusb_dev;
-	/* Enable power to the ports */
+
+	/*
+	 * Enable power to the ports:
+	 * Here we Power-cycle the ports: aka,
+	 * turning them off and turning on again.
+	 */
 	debug("enabling power on all ports\n");
 	for (i = 0; i < dev->maxchild; i++) {
-		/*
-		 * Power-cycle the ports here: aka,
-		 * turning them off and turning on again.
-		 */
 		usb_clear_port_feature(dev, i + 1, USB_PORT_FEAT_POWER);
 		debug("port %d returns %lX\n", i + 1, dev->status);
+	}
 
-		/* Wait at least 2*bPwrOn2PwrGood for PP to change */
-		mdelay(pgood_delay);
+	/* Wait at least 2*bPwrOn2PwrGood for PP to change */
+	mdelay(pgood_delay);
 
+	for (i = 0; i < dev->maxchild; i++) {
 		ret = usb_get_port_status(dev, i + 1, portsts);
 		if (ret < 0) {
 			debug("port %d: get_port_status failed\n", i + 1);
@@ -138,7 +141,9 @@ static void usb_hub_power_on(struct usb_hub_device *hub)
 			debug("port %d: Port power change failed\n", i + 1);
 			return;
 		}
+	}
 
+	for (i = 0; i < dev->maxchild; i++) {
 		usb_set_port_feature(dev, i + 1, USB_PORT_FEAT_POWER);
 		debug("port %d returns %lX\n", i + 1, dev->status);
 	}