2016-12-26 9:01 GMT+01:00 Baolin Wang baolin.wang@linaro.org:
On some platfroms(like x86 platform), when one core is running the USB gadget irq thread handler by dwc3_thread_interrupt(), meanwhile another core also can respond other interrupts from dwc3 controller and modify the event buffer by dwc3_interrupt() function, that will cause getting the wrong event count in irq thread handler to make the USB function abnormal.
We should add spin_lock/unlock() in dwc3_check_event_buf() to avoid this race.
Interesting, I always think we mask interrupt in dwc3_interrupt() by setting DWC3_GEVNTSIZ_INTMASK And unmask interrupt when we end dwc3_thread_interrupt().
So, we shouldn't get any IRQ from HW during dwc3_thread_interrupt(), or I miss something? Do you have some traces that indicate this masking will not work correctly?
BTW, what value you get when problem occured, 0xFFFC?
BR Janusz
Signed-off-by: Baolin Wang baolin.wang@linaro.org
drivers/usb/dwc3/gadget.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 6785595..1a1e1f4 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -2894,10 +2894,13 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt) return IRQ_HANDLED; }
spin_lock(&dwc->lock); count = dwc3_readl(dwc->regs, DWC3_GEVNTCOUNT(0)); count &= DWC3_GEVNTCOUNT_MASK;
if (!count)
if (!count) {
spin_unlock(&dwc->lock); return IRQ_NONE;
} evt->count = count; evt->flags |= DWC3_EVENT_PENDING;
@@ -2914,6 +2917,7 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt) memcpy(evt->cache, evt->buf, count - amount);
dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(0), count);
spin_unlock(&dwc->lock); return IRQ_WAKE_THREAD;
}
1.7.9.5
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