[v2] usb: host: xhci-rcar: Avoid long wait in xhci_reset()

Commit Message

Yoshihiro Shimoda April 25, 2016, 8:36 a.m. UTC

Hi Geert-san,

> From: Geert Uytterhoeven

> Sent: Monday, April 25, 2016 3:58 PM

> 

> Hi Shimoda-san,

> 

> On Mon, Apr 25, 2016 at 4:10 AM, Yoshihiro Shimoda

> <[e-mail]> wrote:

> >> From: Rob Herring

> >> Sent: Friday, April 22, 2016 10:29 PM

> >> On Fri, Apr 22, 2016 at 4:36 AM, Felipe Balbi

> >> <[e-mail]> wrote:

> >> > Yoshihiro Shimoda <[e-mail]> 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: <[e-mail]> # v3.17+

> >> >> Signed-off-by: Yoshihiro Shimoda <[e-mail]>

> >> >> ---

> >> >>  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?

> 

> [...]

> 

> >> We should fix this in kconfig to always enable the option when RCAR is

> >> enabled IMO.

> >

> > I could fix this in kconfig like the followings:

> >

> > diff --git a/arch/arm/mach-shmobile/Kconfig b/arch/arm/mach-shmobile/Kconfig

> > index f2bc5c3..905d1d2 100644

> > --- a/arch/arm/mach-shmobile/Kconfig

> > +++ b/arch/arm/mach-shmobile/Kconfig

> > @@ -46,6 +46,7 @@ menuconfig ARCH_RENESAS

> >         select PINCTRL

> >         select ARCH_REQUIRE_GPIOLIB

> >         select ZONE_DMA if ARM_LPAE

> > +       select USB_XHCI_RCAR if USB_XHCI_HCD

> >

> >  if ARCH_RENESAS

> >

> > diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms

> > index efa77c1..010d2b7 100644

> > --- a/arch/arm64/Kconfig.platforms

> > +++ b/arch/arm64/Kconfig.platforms

> > @@ -105,6 +105,7 @@ config ARCH_RENESAS

> >         select PM

> >         select PM_GENERIC_DOMAINS

> >         select RENESAS_IRQC

> > +       select USB_XHCI_RCAR if USB_XHCI_HCD

> >         help

> >           This enables support for the ARMv8 based Renesas SoCs.

> >

> > If this is acceptable, I will send each patch to arm / arm64.

> 

> What about enforcing this in a single place instead, i.e. in

> drivers/usb/host/Kconfig?


Thank you for the suggestion. I could make such a patch.
I prefer this than each arm / arm64 patch.


Best regards,
Yoshihiro Shimoda

> Gr{oetje,eeting}s,

> 

>                         Geert

> 

> --

> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [e-mail]

> 

> In personal conversations with technical people, I call myself a hacker. But

> when I'm talking to journalists I just say "programmer" or something like that.

>                                 -- Linus Torvalds

Patch

diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
index 3050b18..e9d4dde 100644
--- a/drivers/usb/host/Kconfig
+++ b/drivers/usb/host/Kconfig
@@ -35,6 +35,7 @@  config USB_XHCI_PCI
 
 config USB_XHCI_PLATFORM
 	tristate "Generic xHCI driver for a platform device"
+	select USB_XHCI_RCAR if ARCH_RENESAS
 	---help---
 	  Adds an xHCI host driver for a generic platform device, which
 	  provides a memory space and an irq.
@@ -63,7 +64,7 @@  config USB_XHCI_MVEBU
 
 config USB_XHCI_RCAR
 	tristate "xHCI support for Renesas R-Car SoCs"
-	select USB_XHCI_PLATFORM
+	depends on USB_XHCI_PLATFORM
 	depends on ARCH_RENESAS || COMPILE_TEST
 	---help---
 	  Say 'Y' to enable the support for the xHCI host controller