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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
View file

@ -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",

4
include/dm/device.h
View file

@ -165,6 +165,7 @@ enum {
* automatically when the device is removed / unbound
* @dma_offset: Offset between the physical address space (CPU's) and the
* device's bus address space
* @iommu: IOMMU device associated with this device
*/
struct udevice {
const struct driver *driver;
@ -194,6 +195,9 @@ struct udevice {
#if CONFIG_IS_ENABLED(DM_DMA)
ulong dma_offset;
#endif
#if CONFIG_IS_ENABLED(IOMMU)
struct udevice *iommu;
#endif
};
static inline int dm_udevice_size(void)

24
include/iommu.h
View file

@ -3,6 +3,27 @@
struct udevice;
struct iommu_ops {
/**
* map() - map DMA memory
*
* @dev: device for which to map DMA memory
* @addr: CPU address of the memory
* @size: size of the memory
* @return DMA address for the device
*/
dma_addr_t (*map)(struct udevice *dev, void *addr, size_t size);
/**
* unmap() - unmap DMA memory
*
* @dev: device for which to unmap DMA memory
* @addr: DMA address of the memory
* @size: size of the memory
*/
void (*unmap)(struct udevice *dev, dma_addr_t addr, size_t size);
};
#if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)) && \
CONFIG_IS_ENABLED(IOMMU)
int dev_iommu_enable(struct udevice *dev);
@ -13,4 +34,7 @@ static inline int dev_iommu_enable(struct udevice *dev)
}
#endif
dma_addr_t dev_iommu_dma_map(struct udevice *dev, void *addr, size_t size);
void dev_iommu_dma_unmap(struct udevice *dev, dma_addr_t addr, size_t size);
#endif