drivers: Remove explicit invocations of mmiowb()

mmiowb() is now implied by spin_unlock() on architectures that require
it, so there is no reason to call it from driver code. This patch was
generated using coccinelle:

	@mmiowb@
	@@
	- mmiowb();

and invoked as:

$ for d in drivers include/linux/qed sound; do \
spatch --include-headers --sp-file mmiowb.cocci --dir $d --in-place; done

NOTE: mmiowb() has only ever guaranteed ordering in conjunction with
spin_unlock(). However, pairing each mmiowb() removal in this patch with
the corresponding call to spin_unlock() is not at all trivial, so there
is a small chance that this change may regress any drivers incorrectly
relying on mmiowb() to order MMIO writes between CPUs using lock-free
synchronisation. If you've ended up bisecting to this commit, you can
reintroduce the mmiowb() calls using wmb() instead, which should restore
the old behaviour on all architectures other than some esoteric ia64
systems.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

2 files changed, 0 insertions, 21 deletions

diff --git a/drivers/net/ethernet/wiznet/w5100.c b/drivers/net/ethernet/wiznet/w5100.c
index d8ba512f166a..1713c2d2dccf 100644
--- a/drivers/net/ethernet/wiznet/w5100.c
+++ b/drivers/net/ethernet/wiznet/w5100.c
@@ -219,7 +219,6 @@ static inline int __w5100_write_direct(struct net_device *ndev, u32 addr,
 static inline int w5100_write_direct(struct net_device *ndev, u32 addr, u8 data)
 {
 	__w5100_write_direct(ndev, addr, data);
-	mmiowb();
 
 	return 0;
 }
@@ -236,7 +235,6 @@ static int w5100_write16_direct(struct net_device *ndev, u32 addr, u16 data)
 {
 	__w5100_write_direct(ndev, addr, data >> 8);
 	__w5100_write_direct(ndev, addr + 1, data);
-	mmiowb();
 
 	return 0;
 }
@@ -260,8 +258,6 @@ static int w5100_writebulk_direct(struct net_device *ndev, u32 addr,
 	for (i = 0; i < len; i++, addr++)
 		__w5100_write_direct(ndev, addr, *buf++);
 
-	mmiowb();
-
 	return 0;
 }
 
@@ -375,7 +371,6 @@ static int w5100_readbulk_indirect(struct net_device *ndev, u32 addr, u8 *buf,
 	for (i = 0; i < len; i++)
 		*buf++ = w5100_read_direct(ndev, W5100_IDM_DR);
 
-	mmiowb();
 	spin_unlock_irqrestore(&mmio_priv->reg_lock, flags);
 
 	return 0;
@@ -394,7 +389,6 @@ static int w5100_writebulk_indirect(struct net_device *ndev, u32 addr,
 	for (i = 0; i < len; i++)
 		__w5100_write_direct(ndev, W5100_IDM_DR, *buf++);
 
-	mmiowb();
 	spin_unlock_irqrestore(&mmio_priv->reg_lock, flags);
 
 	return 0;
diff --git a/drivers/net/ethernet/wiznet/w5300.c b/drivers/net/ethernet/wiznet/w5300.c
index f9da5d6172e3..3f03eecc0479 100644
--- a/drivers/net/ethernet/wiznet/w5300.c
+++ b/drivers/net/ethernet/wiznet/w5300.c
@@ -141,7 +141,6 @@ static u16 w5300_read_indirect(struct w5300_priv *priv, u16 addr)
 
 	spin_lock_irqsave(&priv->reg_lock, flags);
 	w5300_write_direct(priv, W5300_IDM_AR, addr);
-	mmiowb();
 	data = w5300_read_direct(priv, W5300_IDM_DR);
 	spin_unlock_irqrestore(&priv->reg_lock, flags);
 
@@ -154,9 +153,7 @@ static void w5300_write_indirect(struct w5300_priv *priv, u16 addr, u16 data)
 
 	spin_lock_irqsave(&priv->reg_lock, flags);
 	w5300_write_direct(priv, W5300_IDM_AR, addr);
-	mmiowb();
 	w5300_write_direct(priv, W5300_IDM_DR, data);
-	mmiowb();
 	spin_unlock_irqrestore(&priv->reg_lock, flags);
 }
 
@@ -192,7 +189,6 @@ static int w5300_command(struct w5300_priv *priv, u16 cmd)
 	unsigned long timeout = jiffies + msecs_to_jiffies(100);
 
 	w5300_write(priv, W5300_S0_CR, cmd);
-	mmiowb();
 
 	while (w5300_read(priv, W5300_S0_CR) != 0) {
 		if (time_after(jiffies, timeout))
@@ -241,18 +237,15 @@ static void w5300_write_macaddr(struct w5300_priv *priv)
 	w5300_write(priv, W5300_SHARH,
 		      ndev->dev_addr[4] << 8 |
 		      ndev->dev_addr[5]);
-	mmiowb();
 }
 
 static void w5300_hw_reset(struct w5300_priv *priv)
 {
 	w5300_write_direct(priv, W5300_MR, MR_RST);
-	mmiowb();
 	mdelay(5);
 	w5300_write_direct(priv, W5300_MR, priv->indirect ?
 				 MR_WDF(7) | MR_PB | MR_IND :
 				 MR_WDF(7) | MR_PB);
-	mmiowb();
 	w5300_write(priv, W5300_IMR, 0);
 	w5300_write_macaddr(priv);
 
@@ -264,24 +257,20 @@ static void w5300_hw_reset(struct w5300_priv *priv)
 	w5300_write32(priv, W5300_TMSRL, 64 << 24);
 	w5300_write32(priv, W5300_TMSRH, 0);
 	w5300_write(priv, W5300_MTYPE, 0x00ff);
-	mmiowb();
 }
 
 static void w5300_hw_start(struct w5300_priv *priv)
 {
 	w5300_write(priv, W5300_S0_MR, priv->promisc ?
 			  S0_MR_MACRAW : S0_MR_MACRAW_MF);
-	mmiowb();
 	w5300_command(priv, S0_CR_OPEN);
 	w5300_write(priv, W5300_S0_IMR, S0_IR_RECV | S0_IR_SENDOK);
 	w5300_write(priv, W5300_IMR, IR_S0);
-	mmiowb();
 }
 
 static void w5300_hw_close(struct w5300_priv *priv)
 {
 	w5300_write(priv, W5300_IMR, 0);
-	mmiowb();
 	w5300_command(priv, S0_CR_CLOSE);
 }
 
@@ -372,7 +361,6 @@ static netdev_tx_t w5300_start_tx(struct sk_buff *skb, struct net_device *ndev)
 	netif_stop_queue(ndev);
 
 	w5300_write_frame(priv, skb->data, skb->len);
-	mmiowb();
 	ndev->stats.tx_packets++;
 	ndev->stats.tx_bytes += skb->len;
 	dev_kfree_skb(skb);
@@ -419,7 +407,6 @@ static int w5300_napi_poll(struct napi_struct *napi, int budget)
 	if (rx_count < budget) {
 		napi_complete_done(napi, rx_count);
 		w5300_write(priv, W5300_IMR, IR_S0);
-		mmiowb();
 	}
 
 	return rx_count;
@@ -434,7 +421,6 @@ static irqreturn_t w5300_interrupt(int irq, void *ndev_instance)
 	if (!ir)
 		return IRQ_NONE;
 	w5300_write(priv, W5300_S0_IR, ir);
-	mmiowb();
 
 	if (ir & S0_IR_SENDOK) {
 		netif_dbg(priv, tx_done, ndev, "tx done\n");
@@ -444,7 +430,6 @@ static irqreturn_t w5300_interrupt(int irq, void *ndev_instance)
 	if (ir & S0_IR_RECV) {
 		if (napi_schedule_prep(&priv->napi)) {
 			w5300_write(priv, W5300_IMR, 0);
-			mmiowb();
 			__napi_schedule(&priv->napi);
 		}
 	}