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, 5 deletions

diff --git a/drivers/ssb/pci.c b/drivers/ssb/pci.c
index 84807a9b4b13..da2d2ab8104d 100644
--- a/drivers/ssb/pci.c
+++ b/drivers/ssb/pci.c
@@ -305,7 +305,6 @@ static int sprom_do_write(struct ssb_bus *bus, const u16 *sprom)
 		else if (i % 2)
 			pr_cont(".");
 		writew(sprom[i], bus->mmio + bus->sprom_offset + (i * 2));
-		mmiowb();
 		msleep(20);
 	}
 	err = pci_read_config_dword(pdev, SSB_SPROMCTL, &spromctl);
diff --git a/drivers/ssb/pcmcia.c b/drivers/ssb/pcmcia.c
index 567013f8a8be..d7d730c245c5 100644
--- a/drivers/ssb/pcmcia.c
+++ b/drivers/ssb/pcmcia.c
@@ -338,7 +338,6 @@ static void ssb_pcmcia_write8(struct ssb_device *dev, u16 offset, u8 value)
 	err = select_core_and_segment(dev, &offset);
 	if (likely(!err))
 		writeb(value, bus->mmio + offset);
-	mmiowb();
 	spin_unlock_irqrestore(&bus->bar_lock, flags);
 }
 
@@ -352,7 +351,6 @@ static void ssb_pcmcia_write16(struct ssb_device *dev, u16 offset, u16 value)
 	err = select_core_and_segment(dev, &offset);
 	if (likely(!err))
 		writew(value, bus->mmio + offset);
-	mmiowb();
 	spin_unlock_irqrestore(&bus->bar_lock, flags);
 }
 
@@ -368,7 +366,6 @@ static void ssb_pcmcia_write32(struct ssb_device *dev, u16 offset, u32 value)
 		writew((value & 0x0000FFFF), bus->mmio + offset);
 		writew(((value & 0xFFFF0000) >> 16), bus->mmio + offset + 2);
 	}
-	mmiowb();
 	spin_unlock_irqrestore(&bus->bar_lock, flags);
 }
 
@@ -424,7 +421,6 @@ static void ssb_pcmcia_block_write(struct ssb_device *dev, const void *buffer,
 		WARN_ON(1);
 	}
 unlock:
-	mmiowb();
 	spin_unlock_irqrestore(&bus->bar_lock, flags);
 }
 #endif /* CONFIG_SSB_BLOCKIO */