From: Sergei Shtylyov
> Hello.
>
> On 12/15/2014 4:03 PM, Boris Brezillon wrote:
>
> > Avoid interpreting useless status flags when we're not waiting for such
> > events by masking the status variable with the interrupt enabled register
> > value.
>
> > Reported-by: Patrice VILCHEZ <patrice.vilc...@atmel.com>
> > Signed-off-by: Boris Brezillon <boris.brezil...@free-electrons.com>
> > ---
> > drivers/usb/gadget/udc/atmel_usba_udc.c | 6 +++++-
> > 1 file changed, 5 insertions(+), 1 deletion(-)
>
> > diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.c
> > b/drivers/usb/gadget/udc/atmel_usba_udc.c
> > index 55c8dde..bc3a532 100644
> > --- a/drivers/usb/gadget/udc/atmel_usba_udc.c
> > +++ b/drivers/usb/gadget/udc/atmel_usba_udc.c
> > @@ -1612,12 +1612,14 @@ static irqreturn_t usba_udc_irq(int irq, void
> > *devid)
> >
> > spin_lock(&udc->lock);
> >
> > - status = usba_readl(udc, INT_STA);
> > + status = usba_readl(udc, INT_STA) & usba_readl(udc, INT_ENB);
> > DBG(DBG_INT, "irq, status=%#08x\n", status);
> >
> > if (status & USBA_DET_SUSPEND) {
> > toggle_bias(udc, 0);
> > usba_writel(udc, INT_CLR, USBA_DET_SUSPEND);
> > + usba_writel(udc, INT_ENB,
> > + usba_readl(udc, INT_ENB) | USBA_WAKE_UP);
> > udc->bias_pulse_needed = true;
> > DBG(DBG_BUS, "Suspend detected\n");
> > if (udc->gadget.speed != USB_SPEED_UNKNOWN
> > @@ -1631,6 +1633,8 @@ static irqreturn_t usba_udc_irq(int irq, void *devid)
> > if (status & USBA_WAKE_UP) {
> > toggle_bias(udc, 1);
> > usba_writel(udc, INT_CLR, USBA_WAKE_UP);
> > + usba_writel(udc, INT_ENB,
> > + usba_readl(udc, INT_ENB) & ~USBA_WAKE_UP);
> > DBG(DBG_BUS, "Wake Up CPU detected\n");
> > }
>
> Looks like t make sense to read the INT_ENB register into a separate
> variable, to save on extra reads?
Better still remember the written value in one of the structures so
that it doesn't have to be read at all.
David
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