hw_ep_prime sometimes fails if irq occurs while it rus on RT kernel.
local_irq_save/restore is added inside the function to gurantee atomicity.
only effective for preempt_rt since hw_ep_prime is called inside top half
or spin_lock_irqsave. No effect is expected for standard linux.
Signed-off-by: Jeaho Hwang <jhhwang@xxxxxxxxxx>
diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
index 8834ca613721..a624eddb3e22 100644
--- a/drivers/usb/chipidea/udc.c
+++ b/drivers/usb/chipidea/udc.c
@@ -191,22 +191,31 @@ static int hw_ep_get_halt(struct ci_hdrc *ci, int num, int dir)
static int hw_ep_prime(struct ci_hdrc *ci, int num, int dir, int is_ctrl)
{
int n = hw_ep_bit(num, dir);
+ unsigned long flags;
+ int ret = 0;
/* Synchronize before ep prime */
wmb();
- if (is_ctrl && dir == RX && hw_read(ci, OP_ENDPTSETUPSTAT, BIT(num)))
+ /* irq affects this routine so irq should be disabled on RT.
+ * on standard kernel, irq is already disabled by callers.
+ */
+ local_irq_save(flags);
+ if (is_ctrl && dir == RX && hw_read(ci, OP_ENDPTSETUPSTAT, BIT(num))) {
+ local_irq_restore(flags);
return -EAGAIN;
+ }
hw_write(ci, OP_ENDPTPRIME, ~0, BIT(n));
while (hw_read(ci, OP_ENDPTPRIME, BIT(n)))
cpu_relax();
if (is_ctrl && dir == RX && hw_read(ci, OP_ENDPTSETUPSTAT, BIT(num)))
- return -EAGAIN;
+ ret = -EAGAIN;
+ local_irq_restore(flags);
/* status shoult be tested according with manual but it doesn't work */
- return 0;
+ return ret;
}
/**
--
2.25.1
