diff options
| author | Will Deacon <will.deacon@arm.com> | 2019-02-22 17:14:59 +0000 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2019-04-08 12:01:02 +0100 |
| commit | fb24ea52f78e0d595852e09e3a55697c8f442189 (patch) | |
| tree | 00ca29c7b0b8df6258a1ad1faf34f6e838ada26c /drivers/dma/txx9dmac.c | |
| parent | 949b8c72768e3a7c69d270962b8a142ee8deec1b (diff) | |
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>
Diffstat (limited to 'drivers/dma/txx9dmac.c')
| -rw-r--r-- | drivers/dma/txx9dmac.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/drivers/dma/txx9dmac.c b/drivers/dma/txx9dmac.c index eb45af71d3a3..e8d0881b64d8 100644 --- a/drivers/dma/txx9dmac.c +++ b/drivers/dma/txx9dmac.c @@ -327,7 +327,6 @@ static void txx9dmac_reset_chan(struct txx9dmac_chan *dc) channel_writel(dc, SAIR, 0); channel_writel(dc, DAIR, 0); channel_writel(dc, CCR, 0); - mmiowb(); } /* Called with dc->lock held and bh disabled */ @@ -954,7 +953,6 @@ static void txx9dmac_chain_dynamic(struct txx9dmac_chan *dc, dma_sync_single_for_device(chan2parent(&dc->chan), prev->txd.phys, ddev->descsize, DMA_TO_DEVICE); - mmiowb(); if (!(channel_readl(dc, CSR) & TXX9_DMA_CSR_CHNEN) && channel_read_CHAR(dc) == prev->txd.phys) /* Restart chain DMA */ @@ -1080,7 +1078,6 @@ static void txx9dmac_free_chan_resources(struct dma_chan *chan) static void txx9dmac_off(struct txx9dmac_dev *ddev) { dma_writel(ddev, MCR, 0); - mmiowb(); } static int __init txx9dmac_chan_probe(struct platform_device *pdev) |