[XEN RFC PATCH 19/40] xen: fdt: Introduce a helper to check fdt node type

[Wei Chen <wei.chen@xxxxxxx>]

In later patches, we will parse CPU and memory NUMA information
from device tree. FDT is using device type property to indicate
CPU nodes and memory nodes. So we introduce fdt_node_check_type
in this patch to avoid redundant code in subsequent patches.

Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
---
 xen/common/libfdt/fdt_ro.c      | 15 +++++++++++++++
 xen/include/xen/libfdt/libfdt.h | 25 +++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/xen/common/libfdt/fdt_ro.c b/xen/common/libfdt/fdt_ro.c
index 36f9b480d1..ae7794d870 100644
--- a/xen/common/libfdt/fdt_ro.c
+++ b/xen/common/libfdt/fdt_ro.c
@@ -545,6 +545,21 @@ int fdt_node_check_compatible(const void *fdt, int 
nodeoffset,
                return 1;
 }
 
+int fdt_node_check_type(const void *fdt, int nodeoffset,
+                             const char *type)
+{
+       const void *prop;
+       int len;
+
+       prop = fdt_getprop(fdt, nodeoffset, "device_type", &len);
+       if (!prop)
+               return len;
+       if (fdt_stringlist_contains(prop, len, type))
+               return 0;
+       else
+               return 1;
+}
+
 int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
                                  const char *compatible)
 {
diff --git a/xen/include/xen/libfdt/libfdt.h b/xen/include/xen/libfdt/libfdt.h
index 7c75688a39..7e4930dbcd 100644
--- a/xen/include/xen/libfdt/libfdt.h
+++ b/xen/include/xen/libfdt/libfdt.h
@@ -799,6 +799,31 @@ int fdt_node_offset_by_phandle(const void *fdt, uint32_t 
phandle);
 int fdt_node_check_compatible(const void *fdt, int nodeoffset,
                              const char *compatible);
 
+/**
+ * fdt_node_check_type: check a node's device_type property
+ * @fdt: pointer to the device tree blob
+ * @nodeoffset: offset of a tree node
+ * @type: string to match against
+ *
+ *
+ * fdt_node_check_type() returns 0 if the given node contains a 'device_type'
+ * property with the given string as one of its elements, it returns non-zero
+ * otherwise, or on error.
+ *
+ * returns:
+ *     0, if the node has a 'device_type' property listing the given string
+ *     1, if the node has a 'device_type' property, but it does not list
+ *             the given string
+ *     -FDT_ERR_NOTFOUND, if the given node has no 'device_type' property
+ *     -FDT_ERR_BADOFFSET, if nodeoffset does not refer to a BEGIN_NODE tag
+ *     -FDT_ERR_BADMAGIC,
+ *     -FDT_ERR_BADVERSION,
+ *     -FDT_ERR_BADSTATE,
+ *     -FDT_ERR_BADSTRUCTURE, standard meanings
+ */
+int fdt_node_check_type(const void *fdt, int nodeoffset,
+                             const char *type);
+
 /**
  * fdt_node_offset_by_compatible - find nodes with a given 'compatible' value
  * @fdt: pointer to the device tree blob
-- 
2.25.1