lk2nd: util: lkfdt: Add more phandle helpers used in qebspil

These are not used in lk2nd yet, but might come useful in the future.

Author: stephan-gh

lk2nd/include/lk2nd/util/lkfdt.h

@@ -48,6 +48,30 @@ bool lkfdt_node_is_available(const void *fdt, int node) __PURE;
  */
 int lkfdt_get_reg(const void *fdt, int parent, int node, uint32_t *addr, uint32_t *size) __PURE;
 
+/**
+ * lkfdt_read_phandle() - Read phandle from property.
+ * @fdt: Device tree blob
+ * @node: Device tree node offset
+ * @prop: Name of property that contains the phandle
+ * @phandle: Ouput variable that is filled with the phandle value
+ *
+ * Return: 0 if successful, <0 libfdt error
+ */
+int lkfdt_read_phandle(const void *fdt, int node, const char *prop, uint32_t *phandle) __PURE;
+
+/**
+ * lkfdt_phandlelist_get() - Read one specific phandle from a list.
+ * @fdt: Device tree blob
+ * @node: Device tree node offset
+ * @prop: Name of property that contains the phandle list
+ * @idx: Index of phandle to return from the list
+ * @phandle: Output variable that is filled with the phandle value
+ *
+ * Return: 0 if successful, <0 libfdt errror (e.g. -FDT_ERR_NOTFOUND)
+ */
+int lkfdt_phandlelist_get(const void *fdt, int node, const char *prop,
+			  int idx, uint32_t *phandle) __PURE;
+
 /**
  * lkfdt_lookup_phandle() - Read phandle from property and search for the node.
  * @fdt: Device tree blob
@@ -60,6 +84,21 @@ int lkfdt_get_reg(const void *fdt, int parent, int node, uint32_t *addr, uint32_
  */
 int lkfdt_lookup_phandle(const void *fdt, int node, const char *prop) __PURE;
 
+/**
+ * lkfdt_subnode_offset_by_phandle() - Return subnode that matches a phandle.
+ * @fdt: Device tree blob
+ * @parent: Device tree node offset of parent
+ * @phandle: The phandle to search for
+ *
+ * Iterate over all subnodes of the "parent" and look for the node that has
+ * the specified "phandle".
+ *
+ * Return:
+ * * >= 0 - The offset of the subnode that matches the phandle, if successful
+ * *  < 0 - libfdt error (<0), otherwise
+ */
+int lkfdt_subnode_offset_by_phandle(const void *fdt, int parent, uint32_t phandle) __PURE;
+
 /**
  * lkfdt_stringlist_get_all() - Obtain array of strings for a given prop
  * @fdt: Device tree blob

lk2nd/util/lkfdt.c

@@ -66,18 +66,60 @@ int lkfdt_get_reg(const void *fdt, int parent, int node,
 	return 0;
 }
 
-int lkfdt_lookup_phandle(const void *fdt, int node, const char *prop)
+int lkfdt_read_phandle(const void *fdt, int node, const char *prop, uint32_t *phandle)
 {
-	const fdt32_t *phandle;
+	const fdt32_t *val;
 	int len;
 
-	phandle = fdt_getprop(fdt, node, prop, &len);
+	val = fdt_getprop(fdt, node, prop, &len);
 	if (len < 0)
 		return len;
-	if (len != sizeof(*phandle))
+	if (len != sizeof(*val))
 		return -FDT_ERR_BADVALUE;
 
-	return fdt_node_offset_by_phandle(fdt, fdt32_to_cpu(*phandle));
+	*phandle = fdt32_to_cpu(*val);
+	return 0;
+}
+
+int lkfdt_phandlelist_get(const void *fdt, int node, const char *prop,
+			  int idx, uint32_t *phandle)
+{
+	const fdt32_t *phandles;
+	int len;
+
+	phandles = fdt_getprop(fdt, node, prop, &len);
+	if (len < 0)
+		return len;
+	if (len % sizeof(*phandles))
+		return -FDT_ERR_BADVALUE;
+	if (len < ((idx + 1) * (int)sizeof(*phandles)))
+		return -FDT_ERR_NOTFOUND;
+
+	*phandle = fdt32_to_cpu(phandles[idx]);
+	return 0;
+}
+
+int lkfdt_lookup_phandle(const void *fdt, int node, const char *prop)
+{
+	uint32_t phandle;
+	int ret;
+
+	ret = lkfdt_read_phandle(fdt, node, prop, &phandle);
+	if (ret < 0)
+		return ret;
+
+	return fdt_node_offset_by_phandle(fdt, phandle);
+}
+
+int lkfdt_subnode_offset_by_phandle(const void *fdt, int parent, uint32_t phandle)
+{
+	int node;
+
+	fdt_for_each_subnode(node, fdt, parent) {
+		if (fdt_get_phandle(fdt, node) == phandle)
+			return node;
+	}
+	return node;
 }
 
 /**