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* [PATCH v2] usb: chipidea: add loop timeout for hw_ep_set_halt()
@ 2021-08-17  6:43 Jeaho Hwang
  2021-08-24  8:31 ` Jeaho Hwang
  2021-08-26 11:17 ` Greg Kroah-Hartman
  0 siblings, 2 replies; 7+ messages in thread
From: Jeaho Hwang @ 2021-08-17  6:43 UTC (permalink / raw)
  To: Peter Chen, Greg Kroah-Hartman, linux-usb, linux-kernel
  Cc: team-linux, mkbyeon, khchoib

If ctrl EP priming is failed (very rare case in standard linux),
hw_ep_set_halt goes infinite loop. waiting 100 times was enough
for zynq7000.

Signed-off-by: Jeaho Hwang <jhhwang@rtst.co.kr>

diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
index 8834ca613721..d73fadb18f32 100644
--- a/drivers/usb/chipidea/udc.c
+++ b/drivers/usb/chipidea/udc.c
@@ -209,6 +209,9 @@ static int hw_ep_prime(struct ci_hdrc *ci, int num, int dir, int is_ctrl)
 	return 0;
 }
 
+/* enough for zynq7000 evaluation board */
+#define HW_EP_SET_HALT_COUNT_MAX 100
+
 /**
  * hw_ep_set_halt: configures ep halt & resets data toggle after clear (execute
  *                 without interruption)
@@ -221,6 +224,7 @@ static int hw_ep_prime(struct ci_hdrc *ci, int num, int dir, int is_ctrl)
  */
 static int hw_ep_set_halt(struct ci_hdrc *ci, int num, int dir, int value)
 {
+	int count = HW_EP_SET_HALT_COUNT_MAX;
 	if (value != 0 && value != 1)
 		return -EINVAL;
 
@@ -232,9 +236,9 @@ static int hw_ep_set_halt(struct ci_hdrc *ci, int num, int dir, int value)
 		/* data toggle - reserved for EP0 but it's in ESS */
 		hw_write(ci, reg, mask_xs|mask_xr,
 			  value ? mask_xs : mask_xr);
-	} while (value != hw_ep_get_halt(ci, num, dir));
+	} while (value != hw_ep_get_halt(ci, num, dir) && --count > 0);
 
-	return 0;
+	return count ? 0 : -EAGAIN;
 }
 
 /**
-- 
2.25.1


^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2021-08-28  3:10 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-08-17  6:43 [PATCH v2] usb: chipidea: add loop timeout for hw_ep_set_halt() Jeaho Hwang
2021-08-24  8:31 ` Jeaho Hwang
2021-08-26 23:07   ` Peter Chen
2021-08-27  1:35     ` Jeaho Hwang
2021-08-28  1:38       ` Peter Chen
2021-08-28  3:10         ` Jeaho Hwang
2021-08-26 11:17 ` Greg Kroah-Hartman

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