net: fec: add locking for MDIO bus access

Both fec_restart() and fec_stop() both perform a reset of the FEC.  This
reset can result in an in-process MDIO transfer being terminated, which
can lead to the MDIO read/write functions timing out.  Add some locking
to prevent this occuring.

We can't use a spinlock for this as the MDIO accessor functions use
wait_for_completion_timeout(), which sleeps.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
index 19210acabcaa..1757aa7eb473 100644
--- a/drivers/net/ethernet/freescale/fec.h
+++ b/drivers/net/ethernet/freescale/fec.h
@@ -14,6 +14,7 @@
 /****************************************************************************/
 
 #include <linux/clocksource.h>
+#include <linux/mutex.h>
 #include <linux/net_tstamp.h>
 #include <linux/ptp_clock_kernel.h>
 
@@ -310,6 +311,8 @@ struct fec_enet_private {
 	char *tso_hdrs;
 	dma_addr_t tso_hdrs_dma;
 
+	struct mutex mutex;
+
 	struct	platform_device *pdev;
 
 	int	dev_id;