Hi,
> From: Felipe Balbi
> Sent: Friday, April 22, 2016 6:37 PM
>
> Hi,
>
> Yoshihiro Shimoda <[email protected]> writes:
> > The firmware of R-Car USB 3.0 host controller will control the reset.
> > So, if the xhci driver doesn't do firmware downloading (e.g. kernel
> > configuration is CONFIG_USB_XHCI_PLATFORM=y and CONFIG_USB_XHCI_RCAR
> > is not set), the reset of USB 3.0 host controller doesn't work
> > correctly. Then, the host controller will cause long wait in
> > xhci_reset() because the CMD_RESET bit of op_regs->command is not
> > cleared for 10 seconds.
> >
> > So, this patch modifies the xhci_rcar_init_quirk() in xhci-rcar.h
> > to exit the probe function immediately.
> >
> > Fixes: 4ac8918f3a7 (usb: host: xhci-plat: add support for the R-Car H2 and
> > M2 xHCI controllers)
> > Cc: <[email protected]> # v3.17+
> > Signed-off-by: Yoshihiro Shimoda <[email protected]>
> > ---
> > Changes from v1:
> > - Revise the commit log.
> > (http://www.spinics.net/lists/stable/msg130007.html)
> >
> > drivers/usb/host/xhci-rcar.h | 6 +++++-
> > 1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/host/xhci-rcar.h b/drivers/usb/host/xhci-rcar.h
> > index 2941a25..2afed68 100644
> > --- a/drivers/usb/host/xhci-rcar.h
> > +++ b/drivers/usb/host/xhci-rcar.h
> > @@ -24,7 +24,11 @@ static inline void xhci_rcar_start(struct usb_hcd *hcd)
> >
> > static inline int xhci_rcar_init_quirk(struct usb_hcd *hcd)
> > {
> > - return 0;
> > + /*
> > + * To avoid wait and timeout in xhci_reset() if CONFIG_XHCI_RCAR is
> > + * disabled, this function fails.
> > + */
> > + return -ENODEV;
>
> okay, if I understood correctly the thing is that you have a kernel
> built with XHCI platform support but without XHCI RCAR support. Then, if
> you run this kernel on RCAR board, you see this CMD_RESET problem,
> right?
Yes, that's right.
> Isn't this pointing to the fact that xhci-plat.ko built without RCAR
> isn't exactly compatible with RCAR ?
You're correct.
> IOW:
>
> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
> index 676ea458148b..3e39320564ce 100644
> --- a/drivers/usb/host/xhci-plat.c
> +++ b/drivers/usb/host/xhci-plat.c
> @@ -112,6 +112,7 @@ static const struct of_device_id usb_xhci_of_match[] = {
> }, {
> .compatible = "marvell,armada-380-xhci",
> .data = &xhci_plat_marvell_armada,
> +#if IS_ENABLED(CONFIG_USB_XHCI_RCAR)
> }, {
> .compatible = "renesas,xhci-r8a7790",
> .data = &xhci_plat_renesas_rcar_gen2,
> @@ -130,6 +131,7 @@ static const struct of_device_id usb_xhci_of_match[] = {
> }, {
> .compatible = "renesas,rcar-gen3-xhci",
> .data = &xhci_plat_renesas_rcar_gen3,
> +#endif
> },
> {},
> };
I see. This can avoid probing the xhci-plat.ko if RCAR is disabled.
Best regards,
Yoshihiro Shimoda
> Rob, should we limit compatible flags like this ? Without
> CONFIG_USB_XHCI_RCAR, this driver won't work on RCAR but, as you can
> see, this driver might still work on other non-RCAR platforms.
>
> What's your take on this ?
>
> --
> balbi
