libpayload: usbhub: Force enumeration of all connected ports on init

We have found a non-compliant USB hub (RealTek RTS 5413) that does not
set a port's Connect Status Change bit on its USB 3.0 half if the port
had already been connected while the hub was being reset. To work around
this bug, this patch adds code to initially request the status of every
port after a hub was enumerated, clear the Connect Status Change bit if
set, and then enumerate the port iff it is currently connected,
regardless of whether the change bit was set. A similar behavior can
also be found in the Linux kernel.

BRANCH=oak
BUG=b:35929438
TEST=Booted Elm with this change, my USB 3.0 sticks enumerate now even
if they had been plugged in since boot.

Change-Id: I8a28252eb94f005f04866d06e4fc61ea265cee89
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/18729
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

1 files changed, 21 insertions, 1 deletions

diff --git a/payloads/libpayload/drivers/usb/usbhub.c b/payloads/libpayload/drivers/usb/usbhub.c
index f75141eae5..340e47ae3d 100644
--- a/payloads/libpayload/drivers/usb/usbhub.c
+++ b/payloads/libpayload/drivers/usb/usbhub.c
@@ -158,6 +158,21 @@ static const generic_hub_ops_t usb_hub_ops = {
 	.reset_port		= generic_hub_resetport,
 };
 
+/* Clear CSC if set and enumerate port if it's connected regardless of change
+   bits. Some broken hubs don't set CSC if already connected during reset. */
+static void
+usb_hub_port_initialize(usbdev_t *const dev, const int port)
+{
+	unsigned short buf[2];
+	int ret = get_status(dev, port, DR_PORT, sizeof(buf), buf);
+	if (ret < 0)
+		return;
+	if (buf[1] & PORT_CONNECTION)
+		clear_feature(dev, port, SEL_C_PORT_CONNECTION, DR_PORT);
+	if (buf[0] & PORT_CONNECTION)
+		generic_hub_scanport(dev, port);
+}
+
 void
 usb_hub_init(usbdev_t *const dev)
 {
@@ -172,5 +187,10 @@ usb_hub_init(usbdev_t *const dev)
 
 	if (dev->speed == SUPER_SPEED)
 		usb_hub_set_hub_depth(dev);
-	generic_hub_init(dev, desc.bNbrPorts, &usb_hub_ops);
+	if (generic_hub_init(dev, desc.bNbrPorts, &usb_hub_ops) < 0)
+		return;
+
+	int port;
+	for (port = 1; port <= GEN_HUB(dev)->num_ports; ++port)
+		usb_hub_port_initialize(dev, port);
 }