Subject: Re: [PATCH] powerpc/usb: fix bug of kernel hang when initializing usb

From: Benjamin Herrenschmidt <[email-masked]>
Date: Thu, 16 Feb 2012 21:39:15 +1100

On Thu, 2012-02-16 at 18:02 +0800, Shengzhou Liu wrote:
> If USB UTMI PHY is not enable, writing to portsc register will lead to
> kernel hang during boot up.

Thanks, I'll try that tomorrow.

Greg, you're picking that up or should I ?

Cheers,
Ben.

> Signed-off-by: Shengzhou Liu <[email-masked]>
> ---
> Apply for master branch of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git 
> Tested on P5020DS, the issue was reported by Benjamin Herrenschmidt. 
> 
>  drivers/usb/host/ehci-fsl.c |    4 ++++
>  drivers/usb/host/ehci-fsl.h |    1 +
>  2 files changed, 5 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/usb/host/ehci-fsl.c b/drivers/usb/host/ehci-fsl.c
> index c26a82e..0090ed2 100644
> --- a/drivers/usb/host/ehci-fsl.c
> +++ b/drivers/usb/host/ehci-fsl.c
> @@ -216,6 +216,8 @@ static void ehci_fsl_setup_phy(struct ehci_hcd *ehci,
>  			       unsigned int port_offset)
>  {
>  	u32 portsc;
> +	struct usb_hcd *hcd = ehci_to_hcd(ehci);
> +	void __iomem *non_ehci = hcd->regs;
>  
>  	portsc = ehci_readl(ehci, &ehci->regs->port_status[port_offset]);
>  	portsc &= ~(PORT_PTS_MSK | PORT_PTS_PTW);
> @@ -231,6 +233,8 @@ static void ehci_fsl_setup_phy(struct ehci_hcd *ehci,
>  		portsc |= PORT_PTS_PTW;
>  		/* fall through */
>  	case FSL_USB2_PHY_UTMI:
> +		/* enable UTMI PHY */
> +		setbits32(non_ehci + FSL_SOC_USB_CTRL, CTRL_UTMI_PHY_EN);
>  		portsc |= PORT_PTS_UTMI;
>  		break;
>  	case FSL_USB2_PHY_NONE:
> diff --git a/drivers/usb/host/ehci-fsl.h b/drivers/usb/host/ehci-fsl.h
> index bdf43e2..0e400c2 100644
> --- a/drivers/usb/host/ehci-fsl.h
> +++ b/drivers/usb/host/ehci-fsl.h
> @@ -45,6 +45,7 @@
>  #define FSL_SOC_USB_PRICTRL	0x40c	/* NOTE: big-endian */
>  #define FSL_SOC_USB_SICTRL	0x410	/* NOTE: big-endian */
>  #define FSL_SOC_USB_CTRL	0x500	/* NOTE: big-endian */
> +#define CTRL_UTMI_PHY_EN	(1<<9)
>  #define CTRL_PHY_CLK_VALID	(1 << 17)
>  #define SNOOP_SIZE_2GB		0x1e
>  #endif				/* _EHCI_FSL_H */