netdev - [PATCH net-next V2 2/4] igb: serialize access to the time sync interrupt registers.

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Date:	Fri, 21 Nov 2014 10:41:14 +0100
From:	Richard Cochran <richardcochran@...il.com>
To:	<netdev@...r.kernel.org>
Cc:	David Miller <davem@...emloft.net>, <bruce.w.allan@...el.com>,
	Jacob Keller <jacob.e.keller@...el.com>,
	Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
	John Ronciak <john.ronciak@...el.com>,
	Matthew Vick <matthew.vick@...el.com>, Jian Yu <jian.yu@...com>
Subject: [PATCH net-next V2 2/4] igb: serialize access to the time sync interrupt registers.

The time sync related interrupt registers may be manipulated from
different contexts. This patch protects the registers from being
asynchronously changed by the reset function.

Also, the patch removes a misleading comment. The reset function
is disabling a bunch of functions, not enabling them.

Signed-off-by: Richard Cochran <richardcochran@...il.com>
---
 drivers/net/ethernet/intel/igb/igb_ptp.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c
index 794c139..d33252f 100644
--- a/drivers/net/ethernet/intel/igb/igb_ptp.c
+++ b/drivers/net/ethernet/intel/igb/igb_ptp.c
@@ -905,6 +905,7 @@ void igb_ptp_stop(struct igb_adapter *adapter)
 void igb_ptp_reset(struct igb_adapter *adapter)
 {
 	struct e1000_hw *hw = &adapter->hw;
+	unsigned long flags;
 
 	if (!(adapter->flags & IGB_FLAG_PTP))
 		return;
@@ -912,6 +913,8 @@ void igb_ptp_reset(struct igb_adapter *adapter)
 	/* reset the tstamp_config */
 	igb_ptp_set_timestamp_mode(adapter, &adapter->tstamp_config);
 
+	spin_lock_irqsave(&adapter->tmreg_lock, flags);
+
 	switch (adapter->hw.mac.type) {
 	case e1000_82576:
 		/* Dial the nominal frequency. */
@@ -922,23 +925,24 @@ void igb_ptp_reset(struct igb_adapter *adapter)
 	case e1000_i350:
 	case e1000_i210:
 	case e1000_i211:
-		/* Enable the timer functions and interrupts. */
 		wr32(E1000_TSAUXC, 0x0);
 		wr32(E1000_TSIM, TSYNC_INTERRUPTS);
 		wr32(E1000_IMS, E1000_IMS_TS);
 		break;
 	default:
 		/* No work to do. */
-		return;
+		goto out;
 	}
 
 	/* Re-initialize the timer. */
 	if ((hw->mac.type == e1000_i210) || (hw->mac.type == e1000_i211)) {
 		struct timespec ts = ktime_to_timespec(ktime_get_real());
 
-		igb_ptp_settime_i210(&adapter->ptp_caps, &ts);
+		igb_ptp_write_i210(adapter, &ts);
 	} else {
 		timecounter_init(&adapter->tc, &adapter->cc,
 				 ktime_to_ns(ktime_get_real()));
 	}
+out:
+	spin_unlock_irqrestore(&adapter->tmreg_lock, flags);
 }
-- 
1.7.10.4

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