Messages in this thread Patch in this message | | | From | Baolin Wang <> | Subject | [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt handler and irq thread handler | Date | Mon, 26 Dec 2016 16:01:10 +0800 |
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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.
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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