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path: root/drivers/acpi/arm64/iort.c
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Diffstat (limited to 'drivers/acpi/arm64/iort.c')
-rw-r--r--drivers/acpi/arm64/iort.c39
1 files changed, 39 insertions, 0 deletions
diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index f3bbef8bb15a..6aae49c35a95 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -318,6 +318,45 @@ static int iort_id_map(struct acpi_iort_id_mapping *map, u8 type, u32 rid_in,
return 0;
}
+static
+struct acpi_iort_node *iort_node_get_id(struct acpi_iort_node *node,
+ u32 *id_out, u8 type_mask,
+ int index)
+{
+ struct acpi_iort_node *parent;
+ struct acpi_iort_id_mapping *map;
+
+ if (!node->mapping_offset || !node->mapping_count ||
+ index >= node->mapping_count)
+ return NULL;
+
+ map = ACPI_ADD_PTR(struct acpi_iort_id_mapping, node,
+ node->mapping_offset);
+
+ /* Firmware bug! */
+ if (!map->output_reference) {
+ pr_err(FW_BUG "[node %p type %d] ID map has NULL parent reference\n",
+ node, node->type);
+ return NULL;
+ }
+
+ parent = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
+ map->output_reference);
+
+ if (!(IORT_TYPE_MASK(parent->type) & type_mask))
+ return NULL;
+
+ if (map[index].flags & ACPI_IORT_ID_SINGLE_MAPPING) {
+ if (node->type == ACPI_IORT_NODE_NAMED_COMPONENT ||
+ node->type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX) {
+ *id_out = map[index].output_base;
+ return parent;
+ }
+ }
+
+ return NULL;
+}
+
static struct acpi_iort_node *iort_node_map_rid(struct acpi_iort_node *node,
u32 rid_in, u32 *rid_out,
u8 type_mask)