iommu: Implement mapping IOMMUs for PCI devices
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>
diff --git a/drivers/iommu/iommu-uclass.c b/drivers/iommu/iommu-uclass.c
index f6b1457..72f123d 100644
--- a/drivers/iommu/iommu-uclass.c
+++ b/drivers/iommu/iommu-uclass.c
@@ -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 @@
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