gianfar: Replace eieio with wmb for non-PPC archs

Replace PPC specific eieio() with arch independent wmb()
for other architectures, i.e. ARM.
The eieio() macro is not defined on ARM and generates
build error.

Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/gianfar.c

@@ -165,7 +165,7 @@ static void gfar_init_rxbdp(struct gfar_priv_rx_q *rx_queue, struct rxbd8 *bdp,
 	if (bdp == rx_queue->rx_bd_base + rx_queue->rx_ring_size - 1)
 		lstatus |= BD_LFLAG(RXBD_WRAP);
 
-	eieio();
+	gfar_wmb();
 
 	bdp->lstatus = lstatus;
 }
@@ -2371,18 +2371,11 @@ static int gfar_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	 */
 	spin_lock_irqsave(&tx_queue->txlock, flags);
 
-	/* The powerpc-specific eieio() is used, as wmb() has too strong
-	 * semantics (it requires synchronization between cacheable and
-	 * uncacheable mappings, which eieio doesn't provide and which we
-	 * don't need), thus requiring a more expensive sync instruction.  At
-	 * some point, the set of architecture-independent barrier functions
-	 * should be expanded to include weaker barriers.
-	 */
-	eieio();
+	gfar_wmb();
 
 	txbdp_start->lstatus = lstatus;
 
-	eieio(); /* force lstatus write before tx_skbuff */
+	gfar_wmb(); /* force lstatus write before tx_skbuff */
 
 	tx_queue->tx_skbuff[tx_queue->skb_curtx] = skb;
 

drivers/net/ethernet/freescale/gianfar.h

@@ -1241,6 +1241,22 @@ static inline int gfar_is_rx_dma_stopped(struct gfar_private *priv)
 	return gfar_read(&regs->ievent) & IEVENT_GRSC;
 }
 
+static inline void gfar_wmb(void)
+{
+#if defined(CONFIG_PPC)
+	/* The powerpc-specific eieio() is used, as wmb() has too strong
+	 * semantics (it requires synchronization between cacheable and
+	 * uncacheable mappings, which eieio() doesn't provide and which we
+	 * don't need), thus requiring a more expensive sync instruction.  At
+	 * some point, the set of architecture-independent barrier functions
+	 * should be expanded to include weaker barriers.
+	 */
+	eieio();
+#else
+	wmb(); /* order write acesses for BD (or FCB) fields */
+#endif
+}
+
 irqreturn_t gfar_receive(int irq, void *dev_id);
 int startup_gfar(struct net_device *dev);
 void stop_gfar(struct net_device *dev);