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From: robert.jarzmik@free•fr (Robert Jarzmik)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH V2 3/5] usb: gadget: pxa25x_udc: prepare/unprepare clocks in pxa-ssp
Date: Mon, 17 Nov 2014 19:44:28 +0100	[thread overview]
Message-ID: <878uj98y5v.fsf@free.fr> (raw)
In-Reply-To: <1416236863-20898-3-git-send-email-dbaryshkov@gmail.com> (Dmitry Eremin-Solenikov's message of "Mon, 17 Nov 2014 18:07:41 +0300")

Dmitry Eremin-Solenikov <dbaryshkov@gmail•com> writes:

> Change clk_enable/disable() calls to clk_prepare_enable() and
> clk_disable_unprepare().
>
> Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail•com>
> ---
>  drivers/usb/gadget/udc/pxa25x_udc.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/gadget/udc/pxa25x_udc.c b/drivers/usb/gadget/udc/pxa25x_udc.c
> index 42f7eeb..e4964ee 100644
> --- a/drivers/usb/gadget/udc/pxa25x_udc.c
> +++ b/drivers/usb/gadget/udc/pxa25x_udc.c
> @@ -103,8 +103,8 @@ static const char ep0name [] = "ep0";
>  
>  /* IXP doesn't yet support <linux/clk.h> */
>  #define clk_get(dev,name)	NULL
> -#define clk_enable(clk)		do { } while (0)
> -#define clk_disable(clk)	do { } while (0)
> +#define clk_prepare_enable(clk)	do { } while (0)
> +#define clk_disable_unprepare(clk)	do { } while (0)
>  #define clk_put(clk)		do { } while (0)
>  
>  #endif
> @@ -932,7 +932,7 @@ static int pullup(struct pxa25x_udc *udc)
>  		if (!udc->active) {
>  			udc->active = 1;
>  			/* Enable clock for USB device */
> -			clk_enable(udc->clk);
> +			clk_prepare_enable(udc->clk);

Guess what, Russell's remark on i2c and serial made me cross-check.  And there
is a case where this will be called in irq context too ...

See :
-> do_IRQ
  -> lubbock_vbus_irq()
    -> pxa25x_udc_vbus_session()
      -> pullup()
        -> clk_prepare_enable()
          -> CRACK

Note that your patch is not really the faulty one, I think a threaded irq
instead of the "raw" irq should do the trick. And it is granted on UDC api that
vbus function is called in a "sleeping" context (Felipe correct me if I'm
wrong), so a patch to fix this before your current code would be fine.

Cheers.

--
Robert

  reply	other threads:[~2014-11-17 18:44 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-17 15:07 [PATCH V2 1/5] serial: pxa: prepare/unprepare clocks Dmitry Eremin-Solenikov
2014-11-17 15:07 ` [PATCH V2 2/5] i2c: " Dmitry Eremin-Solenikov
2014-11-17 15:51   ` Russell King - ARM Linux
2014-11-17 18:26   ` Wolfram Sang
2014-11-17 15:07 ` [PATCH V2 3/5] usb: gadget: pxa25x_udc: prepare/unprepare clocks in pxa-ssp Dmitry Eremin-Solenikov
2014-11-17 18:44   ` Robert Jarzmik [this message]
2014-11-17 20:05     ` Dmitry Eremin-Solenikov
2014-11-17 20:07       ` Russell King - ARM Linux
2014-11-17 20:09       ` Robert Jarzmik
2014-11-17 23:50       ` Dmitry Eremin-Solenikov
2014-11-19 20:29         ` Robert Jarzmik
2014-11-19 21:11           ` Dmitry Eremin-Solenikov
2014-11-22 13:56           ` Robert Jarzmik
2014-11-22 15:44             ` Dmitry Eremin-Solenikov
2014-11-22 17:18               ` Robert Jarzmik
2014-11-22 17:48                 ` Dmitry Eremin-Solenikov
2014-11-22 17:49                   ` Robert Jarzmik
2014-11-22 17:51                     ` Dmitry Eremin-Solenikov
2014-11-24  7:53                       ` Robert Jarzmik
2014-11-26 22:12                         ` Robert Jarzmik
2014-11-26 22:19                           ` Dmitry Eremin-Solenikov
     [not found]                             ` <87zjbd1tb0.fsf_-_@free.fr>
2014-11-26 22:39                               ` Lubbock interrupts fix (was lubbock udc phy) Dmitry Eremin-Solenikov
2014-11-18 15:49       ` [PATCH V2 3/5] usb: gadget: pxa25x_udc: prepare/unprepare clocks in pxa-ssp Felipe Balbi
2014-11-17 15:07 ` [PATCH V2 4/5] mfd: t7l66xb: prepare/unprepare clocks Dmitry Eremin-Solenikov
2014-11-18 13:14   ` Lee Jones
2014-11-17 15:07 ` [PATCH V2 5/5] mfd: tc6387xb: " Dmitry Eremin-Solenikov
2014-11-18 12:04   ` Lee Jones
2014-11-17 15:51 ` [PATCH V2 1/5] serial: pxa: " Russell King - ARM Linux

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