From mboxrd@z Thu Jan 1 00:00:00 1970 From: sricharan@codeaurora.org (Sricharan R) Date: Tue, 4 Oct 2016 22:33:45 +0530 Subject: [PATCH V3 1/8] arm: dma-mapping: Don't override dma_ops in arch_setup_dma_ops() In-Reply-To: <1475600632-21289-1-git-send-email-sricharan@codeaurora.org> References: <1475600632-21289-1-git-send-email-sricharan@codeaurora.org> Message-ID: <1475600632-21289-2-git-send-email-sricharan@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Laurent Pinchart 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 overridden. 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 --- 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 c6834c0..dde6514 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -2322,6 +2322,15 @@ 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 -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation