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iommu: Implement mapping IOMMUs for PCI devices

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Systems such as Apple's M1 and M2 SoCs may have separate IOMMUs
for each PCIe root port.  In this case the right IOMMU for a
PCI device behind a particular root port is described by an
"iommu-map" property in the device tree.  Parse this property
and use it to find the right IOMMU device for PCI devices.

Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
This commit is contained in:
Mark Kettenis 2023-01-21 20:27:56 +01:00 committed by Tom Rini
parent ba1efb3d24
commit 1fc2329121
1 changed files with 65 additions and 0 deletions
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65
drivers/iommu/iommu-uclass.c
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@ -8,10 +8,71 @@
#include <common.h>
#include <dm.h>
#include <iommu.h>
#include <malloc.h>
#include <phys2bus.h>
#include <asm/io.h>
#if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA))
#if CONFIG_IS_ENABLED(PCI)
static int dev_pci_iommu_enable(struct udevice *dev)
{
struct udevice *parent = dev->parent;
struct udevice *dev_iommu;
u32 *iommu_map;
u32 iommu_map_mask, length, phandle, rid, rid_base;
int i, count, len, ret;
while (parent) {
len = dev_read_size(parent, "iommu-map");
if (len > 0)
break;
parent = parent->parent;
}
if (len <= 0)
return 0;
iommu_map = malloc(len);
if (!iommu_map)
return -ENOMEM;
count = len / sizeof(u32);
ret = dev_read_u32_array(parent, "iommu-map", iommu_map, count);
if (ret < 0) {
free(iommu_map);
return 0;
}
iommu_map_mask = dev_read_u32_default(parent, "iommu-map-mask", ~0);
rid = (dm_pci_get_bdf(dev) >> 8) & iommu_map_mask;
/* Loop over entries until mapping is found. */
for (i = 0; i < count; i += 4) {
rid_base = iommu_map[i];
phandle = iommu_map[i + 1];
length = iommu_map[i + 3];
if (rid < rid_base || rid >= rid_base + length)
continue;
ret = uclass_get_device_by_phandle_id(UCLASS_IOMMU, phandle,
&dev_iommu);
if (ret) {
debug("%s: uclass_get_device_by_ofnode failed: %d\n",
__func__, ret);
free(iommu_map);
return ret;
}
dev->iommu = dev_iommu;
break;
}
free(iommu_map);
return 0;
}
#endif
int dev_iommu_enable(struct udevice *dev)
{
struct ofnode_phandle_args args;
@ -39,6 +100,10 @@ int dev_iommu_enable(struct udevice *dev)
dev->iommu = dev_iommu;
}
if (CONFIG_IS_ENABLED(PCI) && count < 0 &&
device_is_on_pci_bus(dev))
return dev_pci_iommu_enable(dev);
return 0;
}
#endif