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

[Antony Pavlov <antonynpavlov@gmail.com>]

On Tue, 25 Aug 2015 15:59:58 +0300
Peter Mamonov <pmamonov@gmail.com> wrote:

> From: Kuo-Jung Su <dantesu@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@faraday-tech.com>
> Signed-off-by: Peter Mamonov <pmamonov@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
> 


Actually this patch combines two U-boot patches:

  * usb: ehci: prevent bad PORTSC register access (http://lists.denx.de/pipermail/u-boot/2013-May/154319.html)
  * usb: Add new command to set USB 2.0 port test modes (http://lists.denx.de/pipermail/u-boot/2013-March/148104.html)

-- 
Best regards,
  Antony Pavlov

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