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>

1 files changed, 0 insertions, 20 deletions

diff --git a/drivers/net/wireless/broadcom/b43legacy/main.c b/drivers/net/wireless/broadcom/b43legacy/main.c
index 55f411925960..c777efc6dc13 100644
--- a/drivers/net/wireless/broadcom/b43legacy/main.c
+++ b/drivers/net/wireless/broadcom/b43legacy/main.c
@@ -264,7 +264,6 @@ static void b43legacy_ram_write(struct b43legacy_wldev *dev, u16 offset,
 		val = swab32(val);
 
 	b43legacy_write32(dev, B43legacy_MMIO_RAM_CONTROL, offset);
-	mmiowb();
 	b43legacy_write32(dev, B43legacy_MMIO_RAM_DATA, val);
 }
 
@@ -341,14 +340,11 @@ void b43legacy_shm_write32(struct b43legacy_wldev *dev,
 		if (offset & 0x0003) {
 			/* Unaligned access */
 			b43legacy_shm_control_word(dev, routing, offset >> 2);
-			mmiowb();
 			b43legacy_write16(dev,
 					  B43legacy_MMIO_SHM_DATA_UNALIGNED,
 					  (value >> 16) & 0xffff);
-			mmiowb();
 			b43legacy_shm_control_word(dev, routing,
 						   (offset >> 2) + 1);
-			mmiowb();
 			b43legacy_write16(dev, B43legacy_MMIO_SHM_DATA,
 					  value & 0xffff);
 			return;
@@ -356,7 +352,6 @@ void b43legacy_shm_write32(struct b43legacy_wldev *dev,
 		offset >>= 2;
 	}
 	b43legacy_shm_control_word(dev, routing, offset);
-	mmiowb();
 	b43legacy_write32(dev, B43legacy_MMIO_SHM_DATA, value);
 }
 
@@ -368,7 +363,6 @@ void b43legacy_shm_write16(struct b43legacy_wldev *dev, u16 routing, u16 offset,
 		if (offset & 0x0003) {
 			/* Unaligned access */
 			b43legacy_shm_control_word(dev, routing, offset >> 2);
-			mmiowb();
 			b43legacy_write16(dev,
 					  B43legacy_MMIO_SHM_DATA_UNALIGNED,
 					  value);
@@ -377,7 +371,6 @@ void b43legacy_shm_write16(struct b43legacy_wldev *dev, u16 routing, u16 offset,
 		offset >>= 2;
 	}
 	b43legacy_shm_control_word(dev, routing, offset);
-	mmiowb();
 	b43legacy_write16(dev, B43legacy_MMIO_SHM_DATA, value);
 }
 
@@ -471,7 +464,6 @@ static void b43legacy_time_lock(struct b43legacy_wldev *dev)
 	status = b43legacy_read32(dev, B43legacy_MMIO_MACCTL);
 	status |= B43legacy_MACCTL_TBTTHOLD;
 	b43legacy_write32(dev, B43legacy_MMIO_MACCTL, status);
-	mmiowb();
 }
 
 static void b43legacy_time_unlock(struct b43legacy_wldev *dev)
@@ -494,10 +486,8 @@ static void b43legacy_tsf_write_locked(struct b43legacy_wldev *dev, u64 tsf)
 		u32 hi = (tsf & 0xFFFFFFFF00000000ULL) >> 32;
 
 		b43legacy_write32(dev, B43legacy_MMIO_REV3PLUS_TSF_LOW, 0);
-		mmiowb();
 		b43legacy_write32(dev, B43legacy_MMIO_REV3PLUS_TSF_HIGH,
 				    hi);
-		mmiowb();
 		b43legacy_write32(dev, B43legacy_MMIO_REV3PLUS_TSF_LOW,
 				    lo);
 	} else {
@@ -507,13 +497,9 @@ static void b43legacy_tsf_write_locked(struct b43legacy_wldev *dev, u64 tsf)
 		u16 v3 = (tsf & 0xFFFF000000000000ULL) >> 48;
 
 		b43legacy_write16(dev, B43legacy_MMIO_TSF_0, 0);
-		mmiowb();
 		b43legacy_write16(dev, B43legacy_MMIO_TSF_3, v3);
-		mmiowb();
 		b43legacy_write16(dev, B43legacy_MMIO_TSF_2, v2);
-		mmiowb();
 		b43legacy_write16(dev, B43legacy_MMIO_TSF_1, v1);
-		mmiowb();
 		b43legacy_write16(dev, B43legacy_MMIO_TSF_0, v0);
 	}
 }
@@ -1250,7 +1236,6 @@ static void b43legacy_beacon_update_trigger_work(struct work_struct *work)
 		/* The handler might have updated the IRQ mask. */
 		b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK,
 				  dev->irq_mask);
-		mmiowb();
 		spin_unlock_irq(&wl->irq_lock);
 	}
 	mutex_unlock(&wl->mutex);
@@ -1346,7 +1331,6 @@ static void b43legacy_interrupt_tasklet(struct b43legacy_wldev *dev)
 			       dma_reason[2], dma_reason[3],
 			       dma_reason[4], dma_reason[5]);
 			b43legacy_controller_restart(dev, "DMA error");
-			mmiowb();
 			spin_unlock_irqrestore(&dev->wl->irq_lock, flags);
 			return;
 		}
@@ -1396,7 +1380,6 @@ static void b43legacy_interrupt_tasklet(struct b43legacy_wldev *dev)
 		handle_irq_transmit_status(dev);
 
 	b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK, dev->irq_mask);
-	mmiowb();
 	spin_unlock_irqrestore(&dev->wl->irq_lock, flags);
 }
 
@@ -1488,7 +1471,6 @@ static irqreturn_t b43legacy_interrupt_handler(int irq, void *dev_id)
 	dev->irq_reason = reason;
 	tasklet_schedule(&dev->isr_tasklet);
 out:
-	mmiowb();
 	spin_unlock(&dev->wl->irq_lock);
 
 	return ret;
@@ -2781,7 +2763,6 @@ static int b43legacy_op_dev_config(struct ieee80211_hw *hw,
 
 	spin_lock_irqsave(&wl->irq_lock, flags);
 	b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK, dev->irq_mask);
-	mmiowb();
 	spin_unlock_irqrestore(&wl->irq_lock, flags);
 out_unlock_mutex:
 	mutex_unlock(&wl->mutex);
@@ -2900,7 +2881,6 @@ static void b43legacy_op_bss_info_changed(struct ieee80211_hw *hw,
 	spin_lock_irqsave(&wl->irq_lock, flags);
 	b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK, dev->irq_mask);
 	/* XXX: why? */
-	mmiowb();
 	spin_unlock_irqrestore(&wl->irq_lock, flags);
  out_unlock_mutex:
 	mutex_unlock(&wl->mutex);