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iommu: Add DMA mapping operations

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In order to support IOMMUs in non-bypass mode we need device ops
to map and unmap DMA memory.  The map operation enters a mapping
for a region specified by CPU address and size into the translation
table of the IOMMU and returns a DMA address suitable for
programming the device to do DMA.  The unmap operation removes
this mapping from the translation table of the IOMMU.

Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
This commit is contained in:
Mark Kettenis
2023-01-21 20:27:52 +01:00
committed by Tom Rini
parent 053827b3c3
commit dd6b68ed4f
3 changed files with 56 additions and 0 deletions
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28
drivers/iommu/iommu-uclass.c
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@@ -7,6 +7,9 @@
#include <common.h>
#include <dm.h>
#include <iommu.h>
#include <phys2bus.h>
#include <asm/io.h>
#if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA))
int dev_iommu_enable(struct udevice *dev)
@@ -33,12 +36,37 @@ int dev_iommu_enable(struct udevice *dev)
__func__, ret);
return ret;
}
dev->iommu = dev_iommu;
}
return 0;
}
#endif
dma_addr_t dev_iommu_dma_map(struct udevice *dev, void *addr, size_t size)
{
const struct iommu_ops *ops;
if (dev->iommu) {
ops = device_get_ops(dev->iommu);
if (ops && ops->map)
return ops->map(dev->iommu, addr, size);
}
return dev_phys_to_bus(dev, virt_to_phys(addr));
}
void dev_iommu_dma_unmap(struct udevice *dev, dma_addr_t addr, size_t size)
{
const struct iommu_ops *ops;
if (dev->iommu) {
ops = device_get_ops(dev->iommu);
if (ops && ops->unmap)
ops->unmap(dev->iommu, addr, size);
}
}
UCLASS_DRIVER(iommu) = {
.id = UCLASS_IOMMU,
.name = "iommu",