iommu/of: make of_pci_map_rid() available for other devices too

iommu-map property is also used by devices with fsl-mc. This
patch moves the of_pci_map_rid to generic location, so that it
can be used by other busses too.

'of_pci_map_rid' is renamed here to 'of_map_rid' and there is no
functional change done in the API.

Signed-off-by: Nipun Gupta <nipun.gupta@nxp.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 102 insertions, 0 deletions

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 74eaedd5b860..90bf7d9fa17b 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -2045,3 +2045,105 @@ int of_find_last_cache_level(unsigned int cpu)
 
 	return cache_level;
 }
+
+/**
+ * of_map_rid - Translate a requester ID through a downstream mapping.
+ * @np: root complex device node.
+ * @rid: device requester ID to map.
+ * @map_name: property name of the map to use.
+ * @map_mask_name: optional property name of the mask to use.
+ * @target: optional pointer to a target device node.
+ * @id_out: optional pointer to receive the translated ID.
+ *
+ * Given a device requester ID, look up the appropriate implementation-defined
+ * platform ID and/or the target device which receives transactions on that
+ * ID, as per the "iommu-map" and "msi-map" bindings. Either of @target or
+ * @id_out may be NULL if only the other is required. If @target points to
+ * a non-NULL device node pointer, only entries targeting that node will be
+ * matched; if it points to a NULL value, it will receive the device node of
+ * the first matching target phandle, with a reference held.
+ *
+ * Return: 0 on success or a standard error code on failure.
+ */
+int of_map_rid(struct device_node *np, u32 rid,
+	       const char *map_name, const char *map_mask_name,
+	       struct device_node **target, u32 *id_out)
+{
+	u32 map_mask, masked_rid;
+	int map_len;
+	const __be32 *map = NULL;
+
+	if (!np || !map_name || (!target && !id_out))
+		return -EINVAL;
+
+	map = of_get_property(np, map_name, &map_len);
+	if (!map) {
+		if (target)
+			return -ENODEV;
+		/* Otherwise, no map implies no translation */
+		*id_out = rid;
+		return 0;
+	}
+
+	if (!map_len || map_len % (4 * sizeof(*map))) {
+		pr_err("%pOF: Error: Bad %s length: %d\n", np,
+			map_name, map_len);
+		return -EINVAL;
+	}
+
+	/* The default is to select all bits. */
+	map_mask = 0xffffffff;
+
+	/*
+	 * Can be overridden by "{iommu,msi}-map-mask" property.
+	 * If of_property_read_u32() fails, the default is used.
+	 */
+	if (map_mask_name)
+		of_property_read_u32(np, map_mask_name, &map_mask);
+
+	masked_rid = map_mask & rid;
+	for ( ; map_len > 0; map_len -= 4 * sizeof(*map), map += 4) {
+		struct device_node *phandle_node;
+		u32 rid_base = be32_to_cpup(map + 0);
+		u32 phandle = be32_to_cpup(map + 1);
+		u32 out_base = be32_to_cpup(map + 2);
+		u32 rid_len = be32_to_cpup(map + 3);
+
+		if (rid_base & ~map_mask) {
+			pr_err("%pOF: Invalid %s translation - %s-mask (0x%x) ignores rid-base (0x%x)\n",
+				np, map_name, map_name,
+				map_mask, rid_base);
+			return -EFAULT;
+		}
+
+		if (masked_rid < rid_base || masked_rid >= rid_base + rid_len)
+			continue;
+
+		phandle_node = of_find_node_by_phandle(phandle);
+		if (!phandle_node)
+			return -ENODEV;
+
+		if (target) {
+			if (*target)
+				of_node_put(phandle_node);
+			else
+				*target = phandle_node;
+
+			if (*target != phandle_node)
+				continue;
+		}
+
+		if (id_out)
+			*id_out = masked_rid - rid_base + out_base;
+
+		pr_debug("%pOF: %s, using mask %08x, rid-base: %08x, out-base: %08x, length: %08x, rid: %08x -> %08x\n",
+			np, map_name, map_mask, rid_base, out_base,
+			rid_len, rid, masked_rid - rid_base + out_base);
+		return 0;
+	}
+
+	pr_err("%pOF: Invalid %s translation - no match for rid 0x%x on %pOF\n",
+		np, map_name, rid, target && *target ? *target : NULL);
+	return -EFAULT;
+}
+EXPORT_SYMBOL_GPL(of_map_rid);