Add ofw_bus_iommu_map() that maps PCI requester ID to an IOMMU

specifier based on "iommu-map" DTS property.

Sponsored by: UKRI

2 files changed, 46 insertions, 1 deletions

diff --git a/sys/dev/ofw/ofw_bus_subr.c b/sys/dev/ofw/ofw_bus_subr.c
index ea57d1086779..408d554b3c7f 100644
--- a/sys/dev/ofw/ofw_bus_subr.c
+++ b/sys/dev/ofw/ofw_bus_subr.c
@@ -491,6 +491,50 @@ ofw_bus_msimap(phandle_t node, uint16_t pci_rid, phandle_t *msi_parent,
 	return (err);
 }
 
+int
+ofw_bus_iommu_map(phandle_t node, uint16_t pci_rid, phandle_t *iommu_parent,
+    uint32_t *iommu_rid)
+{
+	pcell_t mask, iommu_base, rid_base, rid_length;
+	uint32_t masked_rid;
+	pcell_t map[4];
+	ssize_t len;
+	int err, i;
+
+	len = OF_getproplen(node, "iommu-map");
+	if (len <= 0)
+		return (ENOENT);
+        if (len > sizeof(map))
+                return (ENOMEM);
+
+	len = OF_getencprop(node, "iommu-map", map, 16);
+
+	err = ENOENT;
+	mask = 0xffffffff;
+	OF_getencprop(node, "iommu-map-mask", &mask, sizeof(mask));
+
+	masked_rid = pci_rid & mask;
+	for (i = 0; i < len; i += 4) {
+		rid_base = map[i + 0];
+		rid_length = map[i + 3];
+
+		if (masked_rid < rid_base ||
+		    masked_rid >= (rid_base + rid_length))
+			continue;
+
+		iommu_base = map[i + 2];
+
+		if (iommu_parent != NULL)
+			*iommu_parent = map[i + 1];
+		if (iommu_rid != NULL)
+			*iommu_rid = masked_rid - rid_base + iommu_base;
+		err = 0;
+		break;
+	}
+
+	return (err);
+}
+
 static int
 ofw_bus_reg_to_rl_helper(device_t dev, phandle_t node, pcell_t acells, pcell_t scells,
     struct resource_list *rl, const char *reg_source)
diff --git a/sys/dev/ofw/ofw_bus_subr.h b/sys/dev/ofw/ofw_bus_subr.h
index 45709c92c1f7..89f291f92373 100644
--- a/sys/dev/ofw/ofw_bus_subr.h
+++ b/sys/dev/ofw/ofw_bus_subr.h
@@ -92,8 +92,9 @@ int	ofw_bus_lookup_imap(phandle_t, struct ofw_bus_iinfo *, void *, int,
 int	ofw_bus_search_intrmap(void *, int, void *, int, void *, int, void *,
 	    void *, void *, int, phandle_t *);
 
-/* Routines for processing msi maps */
+/* Routines for processing msi and iommu maps. */
 int ofw_bus_msimap(phandle_t, uint16_t, phandle_t *, uint32_t *);
+int ofw_bus_iommu_map(phandle_t, uint16_t, phandle_t *, uint32_t *);
 
 /* Routines for parsing device-tree data into resource lists. */
 int ofw_bus_reg_to_rl(device_t, phandle_t, pcell_t, pcell_t,