[U-Boot] [PATCH] powerpc/usb: fix bug of CPU hang when missing USB PHY clock

[Marek Vasut <marex@denx.de>]

Dear Shengzhou Liu,

> when missing USB PHY clock, u-boot will hang during USB
> initialization when issuing "usb start". We should check
> USBGP[PHY_CLK_VALID] bit to avoid CPU hanging in this case.
> 
> Signed-off-by: Shengzhou Liu <Shengzhou.Liu@freescale.com>

CCing PPC experts.

> ---
> against master branch of upstream u-boot tree
> 
>  drivers/usb/host/ehci-fsl.c |   22 ++++++++++++++++------
>  1 files changed, 16 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/usb/host/ehci-fsl.c b/drivers/usb/host/ehci-fsl.c
> index 7b8f033..68abf11 100644
> --- a/drivers/usb/host/ehci-fsl.c
> +++ b/drivers/usb/host/ehci-fsl.c
> @@ -30,6 +30,18 @@
> 
>  #include "ehci.h"
> 
> +/* Check USB PHY clock valid */
> +static int usb_phy_clk_valid(struct usb_ehci *ehci)
> +{
> +	if ((!(in_be32(&ehci->control) & PHY_CLK_VALID)) &&
> +			(!in_be32(&ehci->prictrl))) {

(!A && !B) condition can certainly be done without the double negation ;-)

> +		printf("USB PHY clock invalid!\n");

debug() ?

> +		return 0;
> +	} else {
> +		return 1;
> +	}
> +}
> +
>  /*
>   * Create the appropriate control structures to manage
>   * a new EHCI host controller.
> @@ -82,18 +94,16 @@ int ehci_hcd_init(int index, struct ehci_hccr **hccr,
> struct ehci_hcor **hcor) udelay(1000); /* delay required for PHY Clk to
> appear */
>  #endif
>  		out_le32(&(*hcor)->or_portsc[0], PORT_PTS_UTMI);
> +		setbits_be32(&ehci->control, USB_EN);
>  	} else {
> -#if defined(CONFIG_SYS_FSL_USB_INTERNAL_UTMI_PHY)
> -		clrbits_be32(&ehci->control, UTMI_PHY_EN);
>  		setbits_be32(&ehci->control, PHY_CLK_SEL_ULPI);
> +		clrsetbits_be32(&ehci->control, UTMI_PHY_EN, USB_EN);
>  		udelay(1000); /* delay required for PHY Clk to appear */
> -#endif
> +		if (!usb_phy_clk_valid(ehci))
> +			return -EINVAL;
>  		out_le32(&(*hcor)->or_portsc[0], PORT_PTS_ULPI);
>  	}
> 
> -	/* Enable interface. */
> -	setbits_be32(&ehci->control, USB_EN);
> -
>  	out_be32(&ehci->prictrl, 0x0000000c);
>  	out_be32(&ehci->age_cnt_limit, 0x00000040);
>  	out_be32(&ehci->sictrl, 0x00000001);

Best regards,
Marek Vasut