of/irq: Break out msi-map lookup (again)
The PCI msi-map code is already doing double-duty translating IDs and
retrieving MSI parents, which unsurprisingly is the same functionality
we need for the identically-formatted PCI iommu-map property. Drag the
core parsing routine up yet another layer into the general OF-PCI code,
and further generalise it for either kind of lookup in either flavour
of map property.
Acked-by: Rob Herring <robh+dt@kernel.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index 589b30c..b58be12 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -308,3 +308,105 @@
EXPORT_SYMBOL_GPL(of_pci_find_msi_chip_by_node);
#endif /* CONFIG_PCI_MSI */
+
+/**
+ * of_pci_map_rid - Translate a requester ID through a downstream mapping.
+ * @np: root complex device node.
+ * @rid: PCI 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 PCI 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_pci_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("%s: Error: Bad %s length: %d\n", np->full_name,
+ 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("%s: Invalid %s translation - %s-mask (0x%x) ignores rid-base (0x%x)\n",
+ np->full_name, 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("%s: %s, using mask %08x, rid-base: %08x, out-base: %08x, length: %08x, rid: %08x -> %08x\n",
+ np->full_name, map_name, map_mask, rid_base, out_base,
+ rid_len, rid, *id_out);
+ return 0;
+ }
+
+ pr_err("%s: Invalid %s translation - no match for rid 0x%x on %s\n",
+ np->full_name, map_name, rid,
+ target && *target ? (*target)->full_name : "any target");
+ return -EFAULT;
+}