[PATCH] usb: ehci: prevent bad PORTSC register access

[Peter Mamonov]

From: Kuo-Jung Su <dantesu at faraday-tech.com>

1. The 'index' of ehci_submit_root() is not always > 0.

   e.g.
   While it gets invoked from usb_get_descriptor(),
   the 'index' is always a '0'. (See ch.9 of USB2.0)

2. The PORTSC register is not always required, and thus it
   should only report a port error when necessary.
   It would cause a port scan failure if the ehci_submit_root()
   always gets terminated by a port error.

Signed-off-by: Kuo-Jung Su <dantesu at faraday-tech.com>
Signed-off-by: Peter Mamonov <pmamonov at gmail.com>
---
 drivers/usb/host/ehci-hcd.c | 38 ++++++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 58c22db..1146b71 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -476,13 +476,8 @@ ehci_submit_root(struct usb_device *dev, unsigned long pipe, void *buffer,
 	int len, srclen;
 	uint32_t reg;
 	uint32_t *status_reg;
+	int port = le16_to_cpu(req->index);
 
-	if (le16_to_cpu(req->index) >= CONFIG_SYS_USB_EHCI_MAX_ROOT_PORTS) {
-		dev_err(ehci->dev, "The request port(%d) is not configured\n",
-			le16_to_cpu(req->index) - 1);
-		return -1;
-	}
-	status_reg = (uint32_t *)&ehci->hcor->or_portsc[le16_to_cpu(req->index) - 1];
 	srclen = 0;
 
 	dev_dbg(ehci->dev, "req=%u (%#x), type=%u (%#x), value=%u, index=%u\n",
@@ -493,6 +488,21 @@ ehci_submit_root(struct usb_device *dev, unsigned long pipe, void *buffer,
 	typeReq = req->request | (req->requesttype << 8);
 
 	switch (typeReq) {
+	case USB_REQ_GET_STATUS | ((USB_RT_PORT | USB_DIR_IN) << 8):
+	case USB_REQ_SET_FEATURE | ((USB_DIR_OUT | USB_RT_PORT) << 8):
+	case USB_REQ_CLEAR_FEATURE | ((USB_DIR_OUT | USB_RT_PORT) << 8):
+		if (!port || port > CONFIG_SYS_USB_EHCI_MAX_ROOT_PORTS) {
+			printf("The request port(%d) is not configured\n", port - 1);
+			return -1;
+		}
+		status_reg = (uint32_t *)&ehci->hcor->or_portsc[port - 1];
+		break;
+	default:
+		status_reg = NULL;
+		break;
+	}
+
+	switch (typeReq) {
 	case DeviceRequest | USB_REQ_GET_DESCRIPTOR:
 		switch (le16_to_cpu(req->value) >> 8) {
 		case USB_DT_DEVICE:
@@ -571,7 +581,7 @@ ehci_submit_root(struct usb_device *dev, unsigned long pipe, void *buffer,
 		if (reg & EHCI_PS_OCA)
 			tmpbuf[0] |= USB_PORT_STAT_OVERCURRENT;
 		if (reg & EHCI_PS_PR &&
-		    (ehci->portreset & (1 << le16_to_cpu(req->index)))) {
+		    (ehci->portreset & (1 << port))) {
 			int ret;
 			/* force reset to complete */
 			reg = reg & ~(EHCI_PS_PR | EHCI_PS_CLEAR);
@@ -581,7 +591,7 @@ ehci_submit_root(struct usb_device *dev, unsigned long pipe, void *buffer,
 				tmpbuf[0] |= USB_PORT_STAT_RESET;
 			else
 				dev_err(ehci->dev, "port(%d) reset error\n",
-					le16_to_cpu(req->index) - 1);
+					port - 1);
 		}
 		if (reg & EHCI_PS_PP)
 			tmpbuf[1] |= USB_PORT_STAT_POWER >> 8;
@@ -608,7 +618,7 @@ ehci_submit_root(struct usb_device *dev, unsigned long pipe, void *buffer,
 			tmpbuf[2] |= USB_PORT_STAT_C_ENABLE;
 		if (reg & EHCI_PS_OCC)
 			tmpbuf[2] |= USB_PORT_STAT_C_OVERCURRENT;
-		if (ehci->portreset & (1 << le16_to_cpu(req->index)))
+		if (ehci->portreset & (1 << port))
 			tmpbuf[2] |= USB_PORT_STAT_C_RESET;
 
 		srcptr = tmpbuf;
@@ -634,7 +644,7 @@ ehci_submit_root(struct usb_device *dev, unsigned long pipe, void *buffer,
 			    EHCI_PS_IS_LOWSPEED(reg)) {
 				/* Low speed device, give up ownership. */
 				dev_dbg(ehci->dev, "port %d low speed --> companion\n",
-				      req->index - 1);
+				      port - 1);
 				reg |= EHCI_PS_PO;
 				ehci_writel(status_reg, reg);
 				break;
@@ -651,7 +661,7 @@ ehci_submit_root(struct usb_device *dev, unsigned long pipe, void *buffer,
 				 */
 				ehci_powerup_fixup(ehci);
 				mdelay(50);
-				ehci->portreset |= 1 << le16_to_cpu(req->index);
+				ehci->portreset |= 1 << port;
 				/* terminate the reset */
 				ehci_writel(status_reg, reg & ~EHCI_PS_PR);
 				/*
@@ -663,10 +673,10 @@ ehci_submit_root(struct usb_device *dev, unsigned long pipe, void *buffer,
 						2 * 1000);
 				if (!ret)
 					ehci->portreset |=
-						1 << le16_to_cpu(req->index);
+						1 << port;
 				else
 					dev_err(ehci->dev, "port(%d) reset error\n",
-						le16_to_cpu(req->index) - 1);
+						port - 1);
 
 			}
 			break;
@@ -698,7 +708,7 @@ ehci_submit_root(struct usb_device *dev, unsigned long pipe, void *buffer,
 			reg |= EHCI_PS_OCC;
 			break;
 		case USB_PORT_FEAT_C_RESET:
-			ehci->portreset &= ~(1 << le16_to_cpu(req->index));
+			ehci->portreset &= ~(1 << port);
 			break;
 		default:
 			dev_dbg(ehci->dev, "unknown feature %x\n", le16_to_cpu(req->value));
-- 
2.1.4