Patchwork [U-Boot,1/3] usb: hub: Parallelize power-cycling of root-hub ports

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Submitter Vivek Gautam
Date April 24, 2013, 12:50 p.m.
Message ID <1366807813-10481-2-git-send-email-gautam.vivek@samsung.com>
Download mbox | patch
Permalink /patch/239198/
State Accepted
Delegated to: Marek Vasut
Headers show

Comments

Vivek Gautam - April 24, 2013, 12:50 p.m.
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>
---
 common/usb_hub.c |   23 ++++++++++++++---------
 1 files changed, 14 insertions(+), 9 deletions(-)

Patch

diff --git a/common/usb_hub.c b/common/usb_hub.c
index 1e225e6..dad0409 100644
--- a/common/usb_hub.c
+++ b/common/usb_hub.c
@@ -105,22 +105,25 @@  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);
+			printf("port %d: get_port_status failed\n", i + 1);
 			return;
 		}
 
@@ -135,10 +138,12 @@  static void usb_hub_power_on(struct usb_hub_device *hub)
 		 */
 		portstatus = le16_to_cpu(portsts->wPortStatus);
 		if (portstatus & (USB_PORT_STAT_POWER << 1)) {
-			debug("port %d: Port power change failed\n", i + 1);
+			printf("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);
 	}