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Message-Id: <1431644410-2997-2-git-send-email-laurent.pinchart+renesas@ideasonboard.com>
Date: Fri, 15 May 2015 02:00:02 +0300
From: Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>
To: linux-kernel@...r.kernel.org
Cc: linux-arm-kernel@...ts.infradead.org,
iommu@...ts.linux-foundation.org,
Laura Abbott <lauraa@...eaurora.org>,
Arnd Bergmann <arnd@...db.de>,
Mitchel Humpherys <mitchelh@...eaurora.org>,
Joreg Roedel <joro@...tes.org>,
Will Deacon <will.deacon@....com>,
Grant Likely <grant.likely@...aro.org>,
Robin Murphy <robin.murphy@....com>,
Marek Szyprowski <m.szyprowski@...sung.com>,
Thierry Reding <thierry.reding@...il.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [RFC/PATCH 1/9] arm: dma-mapping: Don't override dma_ops in arch_setup_dma_ops()
The arch_setup_dma_ops() function is in charge of setting dma_ops with a
call to set_dma_ops(). set_dma_ops() is also called from
- highbank and mvebu bus notifiers
- dmabounce (to be replaced with swiotlb)
- arm_iommu_attach_device
(arm_iommu_attach_device is itself called from IOMMU and bus master
device drivers)
To allow the arch_setup_dma_ops() call to be moved from device add time
to device probe time we must ensure that dma_ops already setup by any of
the above callers will not be overriden.
Aftering replacing dmabounce with swiotlb, converting IOMMU drivers to
of_xlate and taking care of highbank and mvebu, the workaround should be
removed.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>
---
arch/arm/mm/dma-mapping.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 09c5fe3d30c2..7aa5e339a596 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -2117,6 +2117,15 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
struct dma_map_ops *dma_ops;
dev->archdata.dma_coherent = coherent;
+
+ /*
+ * Don't override the dma_ops if they have already been set. Ideally
+ * this should be the only location where dma_ops are set, remove this
+ * check when all other callers of set_dma_ops will have disappeared.
+ */
+ if (dev->archdata.dma_ops)
+ return;
+
if (arm_setup_iommu_dma_ops(dev, dma_base, size, iommu))
dma_ops = arm_get_iommu_dma_map_ops(coherent);
else
--
2.3.6
--
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