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usb: dwc3: gadget: don't rely on jiffies while holding spinlock 

__dwc3_gadget_wakeup() is called while holding a spinlock, then depends on
jiffies in order to timeout while polling the USB core for a link state
update. In the case the wakeup failed, the timeout will never happen and
will also cause the cpu to stall until rcu_preempt kicks in.

This switches to a "decrement variable and wait" timeout scheme.

Signed-off-by: Nicolas Saenz Julienne <nicolassaenzj@gmail.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
This commit is contained in:
Nicolas Saenz Julienne 2016-08-16 10:22:38 +01:00 committed by Felipe Balbi
parent f4693b08cc
commit d6011f6fc2
1 changed files with 3 additions and 3 deletions
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6
drivers/usb/dwc3/gadget.c
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@ -1433,7 +1433,7 @@ static int dwc3_gadget_get_frame(struct usb_gadget *g)
static int __dwc3_gadget_wakeup(struct dwc3 *dwc)
{
unsigned long timeout;
int retries;
int ret;
u32 reg;
@ -1484,9 +1484,9 @@ static int __dwc3_gadget_wakeup(struct dwc3 *dwc)
}
/* poll until Link State changes to ON */
timeout = jiffies + msecs_to_jiffies(100);
retries = 20000;
while (!time_after(jiffies, timeout)) {
while (retries--) {
reg = dwc3_readl(dwc->regs, DWC3_DSTS);
/* in HS, means ON */