[PATCH 13/15] ACPI / scan: Refactor _CCA enforcement

Christoph Hellwig
2018-12-07T19:08:48Z

From: Robin Murphy <robin.murphy@arm.com>

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>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/acpi/scan.c | 5 +++++
drivers/base/platform.c | 3 +--
drivers/pci/pci-driver.c | 3 +--
3 files changed, 7 insertions(+), 4 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);
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index eae841935a45..c1ddf191711e 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -1138,8 +1138,7 @@ int platform_dma_configure(struct device *dev)
ret = of_dma_configure(dev, dev->of_node, true);
} else if (has_acpi_companion(dev)) {
attr = acpi_get_dma_attr(to_acpi_device_node(dev->fwnode));
- if (attr != DEV_DMA_NOT_SUPPORTED)
- ret = acpi_dma_configure(dev, attr);
+ ret = acpi_dma_configure(dev, attr);
}

return ret;
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index bef17c3fca67..1b58e058b13f 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -1602,8 +1602,7 @@ static int pci_dma_configure(struct device *dev)
struct acpi_device *adev = to_acpi_device_node(bridge->fwnode);
enum dev_dma_attr attr = acpi_get_dma_attr(adev);

- if (attr != DEV_DMA_NOT_SUPPORTED)
- ret = acpi_dma_configure(dev, attr);
+ ret = acpi_dma_configure(dev, acpi_get_dma_attr(adev));
}

pci_put_host_bridge_device(bridge);
--
2.19.1