[U-Boot] [PATCH v3] usbh/ehci: Increase timeout for enumeration

[Vipin Kumar]

The current logic reads the port status just once after usb_hub_power_on and
expects the portstatus and portchange to report the connection status
immediately and correctly.

Few pen drives are not able to report both of them immediately ie. those pens
report the connection change but not the connected state after the first read.
This opportunity once lost is gone for ever because the u-boot, unlike linux or
any other OS, works in polling mode.

This patch modifies the logic to read the port status continuously until the
portstatus and portchange both report a connection change as well as a connected
state or no connection change and no connection. This logic is placed in a
timeout of 10 sec. At the end of it, the pen drive would have either reported a
ONE or a ZERO in bit 1 of portstatus as well as portchange.

It enhances the set of pen drives which can eventually be detected by u-boot

Note: This 10 second timeout is based purely on several experiments done with
the broken pen drives

Signed-off-by: Vipin Kumar <vipin.kumar at st.com>
Acked-by: Igor Grinberg <grinberg at compulab.co.il>
---
Changes in v3
 Added comment (in patch comment as well as code) for the reasons for choosing
 10 seconds as timeout

 common/usb_hub.c | 33 ++++++++++++++++++++++++++++-----
 1 file changed, 28 insertions(+), 5 deletions(-)

diff --git a/common/usb_hub.c b/common/usb_hub.c
index e4a1201..4d75b90 100644
--- a/common/usb_hub.c
+++ b/common/usb_hub.c
@@ -396,14 +396,37 @@ static int usb_hub_configure(struct usb_device *dev)
 	for (i = 0; i < dev->maxchild; i++) {
 		ALLOC_CACHE_ALIGN_BUFFER(struct usb_port_status, portsts, 1);
 		unsigned short portstatus, portchange;
+		int ret;
+		ulong start = get_timer(0);
+
+		/*
+		 * Wait for (whichever finishes first)
+		 *  - A maximum of 10 seconds
+		 *    This is a purely observational value driven by connecting
+		 *    a few broken pen drives and taking the max * 1.5 approach
+		 *  - connection_change and connection state to report same
+		 *    state
+		 */
+		do {
+			ret = usb_get_port_status(dev, i + 1, portsts);
+			if (ret < 0) {
+				USB_HUB_PRINTF("get_port_status failed\n");
+				break;
+			}
+
+			portstatus = le16_to_cpu(portsts->wPortStatus);
+			portchange = le16_to_cpu(portsts->wPortChange);
+
+			if ((portchange & USB_PORT_STAT_C_CONNECTION) ==
+				(portstatus & USB_PORT_STAT_CONNECTION))
+				break;
+
+			mdelay(100);
+		} while (get_timer(start) < CONFIG_SYS_HZ * 10);
 
-		if (usb_get_port_status(dev, i + 1, portsts) < 0) {
-			USB_HUB_PRINTF("get_port_status failed\n");
+		if (ret < 0)
 			continue;
-		}
 
-		portstatus = le16_to_cpu(portsts->wPortStatus);
-		portchange = le16_to_cpu(portsts->wPortChange);
 		USB_HUB_PRINTF("Port %d Status %X Change %X\n",
 				i + 1, portstatus, portchange);
 
-- 
1.8.0