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authorRobin Murphy <robin.murphy@arm.com>2018-12-06 13:20:49 -0800
committerChristoph Hellwig <hch@lst.de>2018-12-13 21:06:13 +0100
commite5361ca29f2fea345c08d2b5cb5e3b1840cbafb8 (patch)
tree697be029cf1427e187d1547d376c719b185b632b /drivers/acpi
parent90ac706e98fcb24fb0b0a259558987f33cc2f0f6 (diff)
downloadlinux-e5361ca29f2fea345c08d2b5cb5e3b1840cbafb8.tar.gz
ACPI / scan: Refactor _CCA enforcement
Rather than checking the DMA attribute at each callsite, just pass it through for acpi_dma_configure() to handle directly. That can then deal with the relatively exceptional DEV_DMA_NOT_SUPPORTED case by explicitly installing dummy DMA ops instead of just skipping setup entirely. This will then free up the dev->dma_ops == NULL case for some valuable fastpath optimisations. Signed-off-by: Robin Murphy <robin.murphy@arm.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Tested-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/scan.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index bd1c59fb0e17..b75ae34ed188 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1456,6 +1456,11 @@ int acpi_dma_configure(struct device *dev, enum dev_dma_attr attr)
const struct iommu_ops *iommu;
u64 dma_addr = 0, size = 0;
+ if (attr == DEV_DMA_NOT_SUPPORTED) {
+ set_dma_ops(dev, &dma_dummy_ops);
+ return 0;
+ }
+
iort_dma_setup(dev, &dma_addr, &size);
iommu = iort_iommu_configure(dev);