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From: "Renaud C." <r.cerrato@til-technologies.fr>
To: barebox <barebox@lists.infradead.org>
Subject: [PATCH 4/7] AT91 UDC, fix recursive poll()
Date: Tue, 12 Mar 2013 17:03:15 +0100	[thread overview]
Message-ID: <CA+7xNQ=XbCFAFrr1z+4rpDBirNHv7w_r+RZwGk-0x=G7Y=TBMA@mail.gmail.com> (raw)


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I noticed some weird behavior using DFU gadget on AT91SAM9260 which worked
1 of 10 times. The bug was due to the usb_gadget_poll() being called while
the previous call was still in progress : some USB calls may takes a lot of
time (ex : DFU erase-then-write), resulting in the poller to be triggered
again while still in the poll() function.

This patch adds a poll lock to the AT91 UDC driver.

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From c9e73cbb704f8e4e3c13a712587f0b4fbbdfcac7 Mon Sep 17 00:00:00 2001
From: Cerrato Renaud <r.cerrato@til-technologies.fr>
Date: Mon, 11 Mar 2013 11:06:06 +0100
Subject: [PATCH] added missing lock for poll

---
 drivers/usb/gadget/at91_udc.c |   14 ++++++++------
 drivers/usb/gadget/at91_udc.h |    1 +
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/gadget/at91_udc.c b/drivers/usb/gadget/at91_udc.c
index 0654038..8ae9119 100644
--- a/drivers/usb/gadget/at91_udc.c
+++ b/drivers/usb/gadget/at91_udc.c
@@ -1340,22 +1340,24 @@ int usb_gadget_poll(void)
 	struct at91_udc	*udc = &controller;
 	u32 value;
 
-	if (!udc->udp_baseaddr)
+	if (!udc->udp_baseaddr || udc->poll_lock)
 		return 0;
 
+	udc->poll_lock = 1;
+
 	value = gpio_get_value(udc->board.vbus_pin);
 	value ^= udc->board.vbus_active_low;
-
-	if (!value) {
-		at91_update_vbus(udc, value);
-		return 0;
-	}
 	at91_update_vbus(udc, value);
 
+	if (!value)
+		goto exit;
+
 	value = at91_udp_read(udc, AT91_UDP_ISR) & (~(AT91_UDP_SOFINT));
 	if (value)
 		at91_udc_irq(udc);
 
+exit:
+	udc->poll_lock = 0;
 	return value;
 }
 
diff --git a/drivers/usb/gadget/at91_udc.h b/drivers/usb/gadget/at91_udc.h
index e592cc5..51145a9 100644
--- a/drivers/usb/gadget/at91_udc.h
+++ b/drivers/usb/gadget/at91_udc.h
@@ -127,6 +127,7 @@ struct at91_udc {
 	unsigned			wait_for_config_ack:1;
 	unsigned			selfpowered:1;
 	unsigned			active_suspend:1;
+	unsigned			poll_lock:1;
 	u8				addr;
 	u32				gpio_vbus_val;
 	struct at91_udc_data		board;
-- 
1.7.2.5


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             reply	other threads:[~2013-03-12 16:04 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-12 16:03 Renaud C. [this message]
2013-03-13 10:31 ` Cerrato Renaud

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