[RFC PATCH 1/6] ACPI/IORT: Set PMCG device parent

[John Garry]

In the IORT, a PMCG node includes a node reference to its associated
device.

Set the PMCG platform device parent device for future referencing.

For now, we only consider setting for when the associated component is an
SMMUv3.

Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
---
 drivers/acpi/arm64/iort.c | 34 ++++++++++++++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 8569b79e8b58..0b687520c3e7 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -1455,7 +1455,7 @@ static __init const struct iort_dev_config *iort_get_dev_cfg(
  * Returns: 0 on success, <0 failure
  */
 static int __init iort_add_platform_device(struct acpi_iort_node *node,
-					   const struct iort_dev_config *ops)
+					   const struct iort_dev_config *ops, struct device *parent)
 {
 	struct fwnode_handle *fwnode;
 	struct platform_device *pdev;
@@ -1466,6 +1466,8 @@ static int __init iort_add_platform_device(struct acpi_iort_node *node,
 	if (!pdev)
 		return -ENOMEM;
 
+	pdev->dev.parent = parent;
+
 	if (ops->dev_set_proximity) {
 		ret = ops->dev_set_proximity(&pdev->dev, node);
 		if (ret)
@@ -1573,6 +1575,11 @@ static void __init iort_enable_acs(struct acpi_iort_node *iort_node)
 static inline void iort_enable_acs(struct acpi_iort_node *iort_node) { }
 #endif
 
+static int iort_fwnode_match(struct device *dev, const void *fwnode)
+{
+	return dev->fwnode == fwnode;
+}
+
 static void __init iort_init_platform_devices(void)
 {
 	struct acpi_iort_node *iort_node, *iort_end;
@@ -1594,11 +1601,34 @@ static void __init iort_init_platform_devices(void)
 				iort_table->length);
 
 	for (i = 0; i < iort->node_count; i++) {
+		struct device *parent = NULL;
+
 		if (iort_node >= iort_end) {
 			pr_err("iort node pointer overflows, bad table\n");
 			return;
 		}
 
+		/* Fixme: handle parent declared in IORT after PMCG */
+		if (iort_node->type == ACPI_IORT_NODE_PMCG) {
+			struct acpi_iort_node *iort_assoc_node;
+			struct acpi_iort_pmcg *pmcg;
+			u32 node_reference;
+
+			pmcg = (struct acpi_iort_pmcg *)iort_node->node_data;
+
+			node_reference = pmcg->node_reference;
+			iort_assoc_node = ACPI_ADD_PTR(struct acpi_iort_node, iort,
+				 node_reference);
+
+			if (iort_assoc_node->type == ACPI_IORT_NODE_SMMU_V3) {
+				struct fwnode_handle *assoc_fwnode;
+
+				assoc_fwnode = iort_get_fwnode(iort_assoc_node);
+
+				parent = bus_find_device(&platform_bus_type, NULL,
+				      assoc_fwnode, iort_fwnode_match);
+			}
+		}
 		iort_enable_acs(iort_node);
 
 		ops = iort_get_dev_cfg(iort_node);
@@ -1609,7 +1639,7 @@ static void __init iort_init_platform_devices(void)
 
 			iort_set_fwnode(iort_node, fwnode);
 
-			ret = iort_add_platform_device(iort_node, ops);
+			ret = iort_add_platform_device(iort_node, ops, parent);
 			if (ret) {
 				iort_delete_fwnode(iort_node);
 				acpi_free_fwnode_static(fwnode);
-- 
2.17.1