[kvm-unit-tests PATCH 1/2] devicetree: search up tree in dt_get_nr_cells

[Andrew Jones <drjones@redhat.com>]

Search up the tree until we find #address-cells/#size-cells.
Also only assign outputs if both address and size are found.

Signed-off-by: Andrew Jones <drjones@redhat.com>
---
 lib/devicetree.c | 17 +++++++++++++----
 lib/devicetree.h |  3 ++-
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/lib/devicetree.c b/lib/devicetree.c
index a5c7f7c69ddfd..d3751e2b7e7f9 100644
--- a/lib/devicetree.c
+++ b/lib/devicetree.c
@@ -24,21 +24,30 @@ int dt_get_nr_cells(int fdtnode, u32 *nr_address_cells, u32 *nr_size_cells)
 {
 	const struct fdt_property *prop;
 	u32 *nr_cells;
-	int len;
+	int len, nac, nsc;
+
+	while (1) {
+		prop = fdt_get_property(fdt, fdtnode, "#address-cells", &len);
+		if (prop != NULL || len != -FDT_ERR_NOTFOUND)
+			break;
+		fdtnode = fdt_parent_offset(fdt, fdtnode);
+	}
 
-	prop = fdt_get_property(fdt, fdtnode, "#address-cells", &len);
 	if (prop == NULL)
 		return len;
 
 	nr_cells = (u32 *)prop->data;
-	*nr_address_cells = fdt32_to_cpu(*nr_cells);
+	nac = fdt32_to_cpu(*nr_cells);
 
 	prop = fdt_get_property(fdt, fdtnode, "#size-cells", &len);
 	if (prop == NULL)
 		return len;
 
 	nr_cells = (u32 *)prop->data;
-	*nr_size_cells = fdt32_to_cpu(*nr_cells);
+	nsc = fdt32_to_cpu(*nr_cells);
+
+	*nr_address_cells = nac;
+	*nr_size_cells = nsc;
 
 	return 0;
 }
diff --git a/lib/devicetree.h b/lib/devicetree.h
index c8c86eeae28b6..09f2509409615 100644
--- a/lib/devicetree.h
+++ b/lib/devicetree.h
@@ -168,7 +168,8 @@ extern int dt_pbus_get_base_compatible(const char *compatible,
 
 /*
  * dt_get_nr_cells sets @nr_address_cells and @nr_size_cells to the
- * #address-cells and #size-cells properties of @fdtnode
+ * #address-cells and #size-cells properties of @fdtnode, potentially
+ * searching up the tree to find them in a parent node.
  * returns
  *  - zero on success
  *  - a negative FDT_ERR_* value on failure
-- 
2.4.11