Hi Sricharan and Laurent,
On 2016-08-09 00:49, Sricharan R wrote:
From: Laurent Pinchart <laurent.pinchart+rene...@ideasonboard.com> 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 <laurent.pinchart+rene...@ideasonboard.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 ff7ed56..4686d66 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -2259,6 +2259,15 @@ 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
Please add also set_dma_ops(dev, NULL) to arm_teardown_iommu_dma_ops() function to this patch, because otherwise dma_ops won't be configured properly if deferred probe of the given device happens: iommu dma ops will be set for the first probe try, then iommu structures will be teared down after EPROBEDEFER error, and then before next probe ties dma_ops will be already set, but no iommu structures are
available. For a convenience, this a fixup patch: https://git.linaro.org/people/marek.szyprowski/linux-srpol.git/commitdiff/55adefd43cee9d4beb15cb1bbd805c5059b56b4f Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
