dm: core: Add operations on device tree references

Since U-Boot supports both a live tree and a flat tree, we need an easy
way to access the tree without worrying about which is currently active.
To support this, U-Boot has the concept of an ofnode, which can refer
either to a live tree node or a flat tree node.

For the live tree, the reference contains a pointer to the node (struct
device_node *) or NULL if the node is invalid. For the flat tree, the
reference contains the node offset or -1 if the node is invalid.

Add a basic set of operations using ofnodes. These are implemented by
using either libfdt functions (in the case of a flat DT reference) or
the live-tree of_...() functions.

Note that it is not possible to have both live and flat references active
at the same time. As soon as the live tree is available, everything in
U-Boot should switch to using that. This avoids confusion and allows us to
assume that the type of a reference is simply based on whether we have a
live tree yet, or not.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/core/Makefile

@@ -12,3 +12,4 @@ obj-$(CONFIG_DM)	+= dump.o
 obj-$(CONFIG_$(SPL_)REGMAP)	+= regmap.o
 obj-$(CONFIG_$(SPL_)SYSCON)	+= syscon-uclass.o
 obj-$(CONFIG_OF_LIVE) += of_access.o
+obj-$(CONFIG_OF_CONTROL) += ofnode.o

drivers/core/ofnode.c

@@ -0,0 +1,552 @@
+/*
+ * Copyright (c) 2017 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <fdtdec.h>
+#include <fdt_support.h>
+#include <libfdt.h>
+#include <dm/of_access.h>
+#include <dm/ofnode.h>
+#include <linux/err.h>
+
+int ofnode_read_u32(ofnode node, const char *propname, u32 *outp)
+{
+	assert(ofnode_valid(node));
+	debug("%s: %s: ", __func__, propname);
+
+	if (ofnode_is_np(node)) {
+		return of_read_u32(ofnode_to_np(node), propname, outp);
+	} else {
+		const int *cell;
+		int len;
+
+		cell = fdt_getprop(gd->fdt_blob, ofnode_to_offset(node),
+				   propname, &len);
+		if (!cell || len < sizeof(int)) {
+			debug("(not found)\n");
+			return -EINVAL;
+		}
+		*outp = fdt32_to_cpu(cell[0]);
+	}
+	debug("%#x (%d)\n", *outp, *outp);
+
+	return 0;
+}
+
+int ofnode_read_u32_default(ofnode node, const char *propname, u32 def)
+{
+	assert(ofnode_valid(node));
+	ofnode_read_u32(node, propname, &def);
+
+	return def;
+}
+
+int ofnode_read_s32_default(ofnode node, const char *propname, s32 def)
+{
+	assert(ofnode_valid(node));
+	ofnode_read_u32(node, propname, (u32 *)&def);
+
+	return def;
+}
+
+bool ofnode_read_bool(ofnode node, const char *propname)
+{
+	bool val;
+
+	assert(ofnode_valid(node));
+	debug("%s: %s: ", __func__, propname);
+
+	if (ofnode_is_np(node)) {
+		val = !!of_find_property(ofnode_to_np(node), propname, NULL);
+	} else {
+		val = !!fdt_getprop(gd->fdt_blob, ofnode_to_offset(node),
+				    propname, NULL);
+	}
+	debug("%s\n", val ? "true" : "false");
+
+	return val;
+}
+
+const char *ofnode_read_string(ofnode node, const char *propname)
+{
+	const char *str = NULL;
+	int len = -1;
+
+	assert(ofnode_valid(node));
+	debug("%s: %s: ", __func__, propname);
+
+	if (ofnode_is_np(node)) {
+		struct property *prop = of_find_property(
+				ofnode_to_np(node), propname, NULL);
+
+		if (prop) {
+			str = prop->value;
+			len = prop->length;
+		}
+	} else {
+		str = fdt_getprop(gd->fdt_blob, ofnode_to_offset(node),
+				  propname, &len);
+	}
+	if (!str) {
+		debug("<not found>\n");
+		return NULL;
+	}
+	if (strnlen(str, len) >= len) {
+		debug("<invalid>\n");
+		return NULL;
+	}
+	debug("%s\n", str);
+
+	return str;
+}
+
+ofnode ofnode_find_subnode(ofnode node, const char *subnode_name)
+{
+	ofnode subnode;
+
+	assert(ofnode_valid(node));
+	debug("%s: %s: ", __func__, subnode_name);
+
+	if (ofnode_is_np(node)) {
+		const struct device_node *np = ofnode_to_np(node);
+
+		for (np = np->child; np; np = np->sibling) {
+			if (!strcmp(subnode_name, np->name))
+				break;
+		}
+		subnode = np_to_ofnode(np);
+	} else {
+		int ooffset = fdt_subnode_offset(gd->fdt_blob,
+				ofnode_to_offset(node), subnode_name);
+		subnode = offset_to_ofnode(ooffset);
+	}
+	debug("%s\n", ofnode_valid(subnode) ?
+	      ofnode_get_name(subnode) : "<none>");
+
+	return subnode;
+}
+
+int ofnode_read_u32_array(ofnode node, const char *propname,
+			  u32 *out_values, size_t sz)
+{
+	assert(ofnode_valid(node));
+	debug("%s: %s: ", __func__, propname);
+
+	if (ofnode_is_np(node)) {
+		return of_read_u32_array(ofnode_to_np(node), propname,
+					 out_values, sz);
+	} else {
+		return fdtdec_get_int_array(gd->fdt_blob,
+					    ofnode_to_offset(node), propname,
+					    out_values, sz);
+	}
+}
+
+ofnode ofnode_first_subnode(ofnode node)
+{
+	assert(ofnode_valid(node));
+	if (ofnode_is_np(node))
+		return np_to_ofnode(node.np->child);
+
+	return offset_to_ofnode(
+		fdt_first_subnode(gd->fdt_blob, ofnode_to_offset(node)));
+}
+
+ofnode ofnode_next_subnode(ofnode node)
+{
+	assert(ofnode_valid(node));
+	if (ofnode_is_np(node))
+		return np_to_ofnode(node.np->sibling);
+
+	return offset_to_ofnode(
+		fdt_next_subnode(gd->fdt_blob, ofnode_to_offset(node)));
+}
+
+const char *ofnode_get_name(ofnode node)
+{
+	assert(ofnode_valid(node));
+	if (ofnode_is_np(node))
+		return strrchr(node.np->full_name, '/') + 1;
+
+	return fdt_get_name(gd->fdt_blob, ofnode_to_offset(node), NULL);
+}
+
+int ofnode_read_size(ofnode node, const char *propname)
+{
+	int len;
+
+	if (ofnode_is_np(node)) {
+		struct property *prop = of_find_property(
+				ofnode_to_np(node), propname, NULL);
+
+		if (prop)
+			return prop->length;
+	} else {
+		if (fdt_getprop(gd->fdt_blob, ofnode_to_offset(node), propname,
+				&len))
+			return len;
+	}
+
+	return -EINVAL;
+}
+
+int ofnode_stringlist_search(ofnode node, const char *property,
+			     const char *string)
+{
+	if (ofnode_is_np(node)) {
+		return of_property_match_string(ofnode_to_np(node),
+						property, string);
+	} else {
+		int ret;
+
+		ret = fdt_stringlist_search(gd->fdt_blob,
+					    ofnode_to_offset(node), property,
+					    string);
+		if (ret == -FDT_ERR_NOTFOUND)
+			return -ENODATA;
+		else if (ret < 0)
+			return -EINVAL;
+
+		return ret;
+	}
+}
+
+int ofnode_read_string_index(ofnode node, const char *property, int index,
+			     const char **outp)
+{
+	if (ofnode_is_np(node)) {
+		return of_property_read_string_index(ofnode_to_np(node),
+						     property, index, outp);
+	} else {
+		int len;
+
+		*outp = fdt_stringlist_get(gd->fdt_blob, ofnode_to_offset(node),
+					   property, index, &len);
+		if (len < 0)
+			return -EINVAL;
+		return 0;
+	}
+}
+
+static void ofnode_from_fdtdec_phandle_args(struct fdtdec_phandle_args *in,
+					    struct ofnode_phandle_args *out)
+{
+	assert(OF_MAX_PHANDLE_ARGS == MAX_PHANDLE_ARGS);
+	out->node = offset_to_ofnode(in->node);
+	out->args_count = in->args_count;
+	memcpy(out->args, in->args, sizeof(out->args));
+}
+
+static void ofnode_from_of_phandle_args(struct of_phandle_args *in,
+					struct ofnode_phandle_args *out)
+{
+	assert(OF_MAX_PHANDLE_ARGS == MAX_PHANDLE_ARGS);
+	out->node = np_to_ofnode(in->np);
+	out->args_count = in->args_count;
+	memcpy(out->args, in->args, sizeof(out->args));
+}
+
+int ofnode_parse_phandle_with_args(ofnode node, const char *list_name,
+				   const char *cells_name, int cell_count,
+				   int index,
+				   struct ofnode_phandle_args *out_args)
+{
+	if (ofnode_is_np(node)) {
+		struct of_phandle_args args;
+		int ret;
+
+		ret = of_parse_phandle_with_args(ofnode_to_np(node),
+				list_name, cells_name, index, &args);
+		if (ret)
+			return ret;
+		ofnode_from_of_phandle_args(&args, out_args);
+	} else {
+		struct fdtdec_phandle_args args;
+		int ret;
+
+		ret = fdtdec_parse_phandle_with_args(gd->fdt_blob,
+				ofnode_to_offset(node), list_name, cells_name,
+				cell_count, index, &args);
+		if (ret)
+			return ret;
+		ofnode_from_fdtdec_phandle_args(&args, out_args);
+	}
+
+	return 0;
+}
+
+ofnode ofnode_path(const char *path)
+{
+	if (of_live_active())
+		return np_to_ofnode(of_find_node_by_path(path));
+	else
+		return offset_to_ofnode(fdt_path_offset(gd->fdt_blob, path));
+}
+
+const char *ofnode_get_chosen_prop(const char *name)
+{
+	ofnode chosen_node;
+
+	chosen_node = ofnode_path("/chosen");
+
+	return ofnode_read_string(chosen_node, name);
+}
+
+ofnode ofnode_get_chosen_node(const char *name)
+{
+	const char *prop;
+
+	prop = ofnode_get_chosen_prop(name);
+	if (!prop)
+		return ofnode_null();
+
+	return ofnode_path(prop);
+}
+
+static int decode_timing_property(ofnode node, const char *name,
+				  struct timing_entry *result)
+{
+	int length, ret = 0;
+
+	length = ofnode_read_size(node, name);
+	if (length < 0) {
+		debug("%s: could not find property %s\n",
+		      ofnode_get_name(node), name);
+		return length;
+	}
+
+	if (length == sizeof(u32)) {
+		result->typ = ofnode_read_u32_default(node, name, 0);
+		result->min = result->typ;
+		result->max = result->typ;
+	} else {
+		ret = ofnode_read_u32_array(node, name, &result->min, 3);
+	}
+
+	return ret;
+}
+
+int ofnode_decode_display_timing(ofnode parent, int index,
+				 struct display_timing *dt)
+{
+	int i;
+	ofnode timings, node;
+	u32 val = 0;
+	int ret = 0;
+
+	timings = ofnode_find_subnode(parent, "display-timings");
+	if (!ofnode_valid(timings))
+		return -EINVAL;
+
+	for (i = 0, node = ofnode_first_subnode(timings);
+	     ofnode_valid(node) && i != index;
+	     node = ofnode_first_subnode(node))
+		i++;
+
+	if (!ofnode_valid(node))
+		return -EINVAL;
+
+	memset(dt, 0, sizeof(*dt));
+
+	ret |= decode_timing_property(node, "hback-porch", &dt->hback_porch);
+	ret |= decode_timing_property(node, "hfront-porch", &dt->hfront_porch);
+	ret |= decode_timing_property(node, "hactive", &dt->hactive);
+	ret |= decode_timing_property(node, "hsync-len", &dt->hsync_len);
+	ret |= decode_timing_property(node, "vback-porch", &dt->vback_porch);
+	ret |= decode_timing_property(node, "vfront-porch", &dt->vfront_porch);
+	ret |= decode_timing_property(node, "vactive", &dt->vactive);
+	ret |= decode_timing_property(node, "vsync-len", &dt->vsync_len);
+	ret |= decode_timing_property(node, "clock-frequency", &dt->pixelclock);
+
+	dt->flags = 0;
+	val = ofnode_read_u32_default(node, "vsync-active", -1);
+	if (val != -1) {
+		dt->flags |= val ? DISPLAY_FLAGS_VSYNC_HIGH :
+				DISPLAY_FLAGS_VSYNC_LOW;
+	}
+	val = ofnode_read_u32_default(node, "hsync-active", -1);
+	if (val != -1) {
+		dt->flags |= val ? DISPLAY_FLAGS_HSYNC_HIGH :
+				DISPLAY_FLAGS_HSYNC_LOW;
+	}
+	val = ofnode_read_u32_default(node, "de-active", -1);
+	if (val != -1) {
+		dt->flags |= val ? DISPLAY_FLAGS_DE_HIGH :
+				DISPLAY_FLAGS_DE_LOW;
+	}
+	val = ofnode_read_u32_default(node, "pixelclk-active", -1);
+	if (val != -1) {
+		dt->flags |= val ? DISPLAY_FLAGS_PIXDATA_POSEDGE :
+				DISPLAY_FLAGS_PIXDATA_NEGEDGE;
+	}
+
+	if (ofnode_read_bool(node, "interlaced"))
+		dt->flags |= DISPLAY_FLAGS_INTERLACED;
+	if (ofnode_read_bool(node, "doublescan"))
+		dt->flags |= DISPLAY_FLAGS_DOUBLESCAN;
+	if (ofnode_read_bool(node, "doubleclk"))
+		dt->flags |= DISPLAY_FLAGS_DOUBLECLK;
+
+	return ret;
+}
+
+const u32 *ofnode_read_prop(ofnode node, const char *propname, int *lenp)
+{
+	if (ofnode_is_np(node)) {
+		struct property *prop;
+
+		prop = of_find_property(ofnode_to_np(node), propname, lenp);
+		if (!prop)
+			return NULL;
+		return prop->value;
+	} else {
+		return fdt_getprop(gd->fdt_blob, ofnode_to_offset(node),
+				   propname, lenp);
+	}
+}
+
+bool ofnode_is_available(ofnode node)
+{
+	if (ofnode_is_np(node))
+		return of_device_is_available(ofnode_to_np(node));
+	else
+		return fdtdec_get_is_enabled(gd->fdt_blob,
+					     ofnode_to_offset(node));
+}
+
+fdt_addr_t ofnode_get_addr_size(ofnode node, const char *property,
+				fdt_size_t *sizep)
+{
+	if (ofnode_is_np(node)) {
+		int na, ns;
+		int psize;
+		const struct device_node *np = ofnode_to_np(node);
+		const __be32 *prop = of_get_property(np, "reg", &psize);
+
+		na = of_n_addr_cells(np);
+		ns = of_n_addr_cells(np);
+		*sizep = of_read_number(prop + na, ns);
+		return of_read_number(prop, na);
+	} else {
+		return fdtdec_get_addr_size(gd->fdt_blob,
+					    ofnode_to_offset(node), property,
+					    sizep);
+	}
+}
+
+const uint8_t *ofnode_read_u8_array_ptr(ofnode node, const char *propname,
+					size_t sz)
+{
+	if (ofnode_is_np(node)) {
+		const struct device_node *np = ofnode_to_np(node);
+		int psize;
+		const __be32 *prop = of_get_property(np, propname, &psize);
+
+		if (!prop || sz != psize)
+			return NULL;
+		return (uint8_t *)prop;
+
+	} else {
+		return fdtdec_locate_byte_array(gd->fdt_blob,
+				ofnode_to_offset(node), propname, sz);
+	}
+}
+
+int ofnode_read_pci_addr(ofnode node, enum fdt_pci_space type,
+			 const char *propname, struct fdt_pci_addr *addr)
+{
+	const u32 *cell;
+	int len;
+	int ret = -ENOENT;
+
+	debug("%s: %s: ", __func__, propname);
+
+	/*
+	 * If we follow the pci bus bindings strictly, we should check
+	 * the value of the node's parent node's #address-cells and
+	 * #size-cells. They need to be 3 and 2 accordingly. However,
+	 * for simplicity we skip the check here.
+	 */
+	cell = ofnode_read_prop(node, propname, &len);
+	if (!cell)
+		goto fail;
+
+	if ((len % FDT_PCI_REG_SIZE) == 0) {
+		int num = len / FDT_PCI_REG_SIZE;
+		int i;
+
+		for (i = 0; i < num; i++) {
+			debug("pci address #%d: %08lx %08lx %08lx\n", i,
+			      (ulong)fdt32_to_cpu(cell[0]),
+			      (ulong)fdt32_to_cpu(cell[1]),
+			      (ulong)fdt32_to_cpu(cell[2]));
+			if ((fdt32_to_cpu(*cell) & type) == type) {
+				addr->phys_hi = fdt32_to_cpu(cell[0]);
+				addr->phys_mid = fdt32_to_cpu(cell[1]);
+				addr->phys_lo = fdt32_to_cpu(cell[1]);
+				break;
+			} else {
+				cell += (FDT_PCI_ADDR_CELLS +
+					 FDT_PCI_SIZE_CELLS);
+			}
+		}
+
+		if (i == num) {
+			ret = -ENXIO;
+			goto fail;
+		}
+
+		return 0;
+	} else {
+		ret = -EINVAL;
+	}
+
+fail:
+	debug("(not found)\n");
+	return ret;
+}
+
+int ofnode_read_addr_cells(ofnode node)
+{
+	if (ofnode_is_np(node))
+		return of_n_addr_cells(ofnode_to_np(node));
+	else
+		return fdt_address_cells(gd->fdt_blob, ofnode_to_offset(node));
+}
+
+int ofnode_read_size_cells(ofnode node)
+{
+	if (ofnode_is_np(node))
+		return of_n_size_cells(ofnode_to_np(node));
+	else
+		return fdt_size_cells(gd->fdt_blob, ofnode_to_offset(node));
+}
+
+bool ofnode_pre_reloc(ofnode node)
+{
+	if (ofnode_read_prop(node, "u-boot,dm-pre-reloc", NULL))
+		return true;
+
+#ifdef CONFIG_TPL_BUILD
+	if (ofnode_read_prop(node, "u-boot,dm-tpl", NULL))
+		return true;
+#elif defined(CONFIG_SPL_BUILD)
+	if (ofnode_read_prop(node, "u-boot,dm-spl", NULL))
+		return true;
+#else
+	/*
+	 * In regular builds individual spl and tpl handling both
+	 * count as handled pre-relocation for later second init.
+	 */
+	if (ofnode_read_prop(node, "u-boot,dm-spl", NULL) ||
+	    ofnode_read_prop(node, "u-boot,dm-tpl", NULL))
+		return true;
+#endif
+
+	return false;
+}

include/dm/ofnode.h

@@ -8,6 +8,13 @@
 #ifndef _DM_OFNODE_H
 #define _DM_OFNODE_H
 
+/* TODO(sjg@chromium.org): Drop fdtdec.h include */
+#include <fdtdec.h>
+#include <dm/of.h>
+
+/* Enable checks to protect against invalid calls */
+#undef OF_CHECKS
+
 /**
  * ofnode - reference to a device tree node
  *
@@ -20,7 +27,7 @@
  * ofnode and either an offset or a struct device_node *.
  *
  * The reference can also hold a null offset, in which case the pointer value
- * here is (void *)-1. This corresponds to a struct device_node * value of
+ * here is NULL. This corresponds to a struct device_node * value of
  * NULL, or an offset of -1.
  *
  * There is no ambiguity as to whether ofnode holds an offset or a node
@@ -44,6 +51,29 @@ typedef union ofnode_union {
 	long of_offset;
 } ofnode;
 
+struct ofnode_phandle_args {
+	ofnode node;
+	int args_count;
+	uint32_t args[OF_MAX_PHANDLE_ARGS];
+};
+
+/**
+ * _ofnode_to_np() - convert an ofnode to a live DT node pointer
+ *
+ * This cannot be called if the reference contains an offset.
+ *
+ * @node: Reference containing struct device_node * (possibly invalid)
+ * @return pointer to device node (can be NULL)
+ */
+static inline const struct device_node *ofnode_to_np(ofnode node)
+{
+#ifdef OF_CHECKS
+	if (!of_live_active())
+		return NULL;
+#endif
+	return node.np;
+}
+
 /**
  * ofnode_to_offset() - convert an ofnode to a flat DT offset
  *
@@ -54,6 +84,10 @@ typedef union ofnode_union {
  */
 static inline int ofnode_to_offset(ofnode node)
 {
+#ifdef OF_CHECKS
+	if (of_live_active())
+		return -1;
+#endif
 	return node.of_offset;
 }
 
@@ -64,7 +98,10 @@ static inline int ofnode_to_offset(ofnode node)
  */
 static inline bool ofnode_valid(ofnode node)
 {
-	return node.of_offset != -1;
+	if (of_live_active())
+		return node.np != NULL;
+	else
+		return node.of_offset != -1;
 }
 
 /**
@@ -77,11 +114,54 @@ static inline ofnode offset_to_ofnode(int of_offset)
 {
 	ofnode node;
 
-	node.of_offset = of_offset;
+	if (of_live_active())
+		node.np = NULL;
+	else
+		node.of_offset = of_offset;
 
 	return node;
 }
 
+/**
+ * np_to_ofnode() - convert a node pointer to an ofnode
+ *
+ * @np: Live node pointer (can be NULL)
+ * @return reference to the associated node pointer
+ */
+static inline ofnode np_to_ofnode(const struct device_node *np)
+{
+	ofnode node;
+
+	node.np = np;
+
+	return node;
+}
+
+/**
+ * ofnode_is_np() - check if a reference is a node pointer
+ *
+ * This function associated that if there is a valid live tree then all
+ * references will use it. This is because using the flat DT when the live tree
+ * is valid is not permitted.
+ *
+ * @node: reference to check (possibly invalid)
+ * @return true if the reference is a live node pointer, false if it is a DT
+ * offset
+ */
+static inline bool ofnode_is_np(ofnode node)
+{
+#ifdef OF_CHECKS
+	/*
+	 * Check our assumption that flat tree offsets are not used when a
+	 * live tree is in use.
+	 */
+	assert(!ofnode_valid(node) ||
+	       (of_live_active() ? _ofnode_to_np(node)
+				  : _ofnode_to_np(node)));
+#endif
+	return of_live_active() && ofnode_valid(node);
+}
+
 /**
  * ofnode_equal() - check if two references are equal
  *
@@ -93,4 +173,385 @@ static inline bool ofnode_equal(ofnode ref1, ofnode ref2)
 	return ref1.of_offset == ref2.of_offset;
 }
 
+/**
+ * ofnode_null() - Obtain a null ofnode
+ *
+ * This returns an ofnode which points to no node. It works both with the flat
+ * tree and livetree.
+ */
+static inline ofnode ofnode_null(void)
+{
+	ofnode node;
+
+	if (of_live_active())
+		node.np = NULL;
+	else
+		node.of_offset = -1;
+
+	return node;
+}
+
+/**
+ * ofnode_read_u32() - Read a 32-bit integer from a property
+ *
+ * @ref:	valid node reference to read property from
+ * @propname:	name of the property to read from
+ * @outp:	place to put value (if found)
+ * @return 0 if OK, -ve on error
+ */
+int ofnode_read_u32(ofnode node, const char *propname, u32 *outp);
+
+/**
+ * ofnode_read_s32() - Read a 32-bit integer from a property
+ *
+ * @ref:	valid node reference to read property from
+ * @propname:	name of the property to read from
+ * @outp:	place to put value (if found)
+ * @return 0 if OK, -ve on error
+ */
+static inline int ofnode_read_s32(ofnode node, const char *propname,
+				  s32 *out_value)
+{
+	return ofnode_read_u32(node, propname, (u32 *)out_value);
+}
+
+/**
+ * ofnode_read_u32_default() - Read a 32-bit integer from a property
+ *
+ * @ref:	valid node reference to read property from
+ * @propname:	name of the property to read from
+ * @def:	default value to return if the property has no value
+ * @return property value, or @def if not found
+ */
+int ofnode_read_u32_default(ofnode ref, const char *propname, u32 def);
+
+/**
+ * ofnode_read_s32_default() - Read a 32-bit integer from a property
+ *
+ * @ref:	valid node reference to read property from
+ * @propname:	name of the property to read from
+ * @def:	default value to return if the property has no value
+ * @return property value, or @def if not found
+ */
+int ofnode_read_s32_default(ofnode node, const char *propname, s32 def);
+
+/**
+ * ofnode_read_string() - Read a string from a property
+ *
+ * @ref:	valid node reference to read property from
+ * @propname:	name of the property to read
+ * @return string from property value, or NULL if there is no such property
+ */
+const char *ofnode_read_string(ofnode node, const char *propname);
+
+/**
+ * ofnode_read_u32_array - Find and read an array of 32 bit integers
+ *
+ * @node:	valid node reference to read property from
+ * @propname:	name of the property to read
+ * @out_values:	pointer to return value, modified only if return value is 0
+ * @sz:		number of array elements to read
+ *
+ * Search for a property in a device node and read 32-bit value(s) from
+ * it. Returns 0 on success, -EINVAL if the property does not exist,
+ * -ENODATA if property does not have a value, and -EOVERFLOW if the
+ * property data isn't large enough.
+ *
+ * The out_values is modified only if a valid u32 value can be decoded.
+ */
+int ofnode_read_u32_array(ofnode node, const char *propname,
+			  u32 *out_values, size_t sz);
+
+/**
+ * ofnode_read_bool() - read a boolean value from a property
+ *
+ * @node:	valid node reference to read property from
+ * @propname:	name of property to read
+ * @return true if property is present (meaning true), false if not present
+ */
+bool ofnode_read_bool(ofnode node, const char *propname);
+
+/**
+ * ofnode_find_subnode() - find a named subnode of a parent node
+ *
+ * @node:	valid reference to parent node
+ * @subnode_name: name of subnode to find
+ * @return reference to subnode (which can be invalid if there is no such
+ * subnode)
+ */
+ofnode ofnode_find_subnode(ofnode node, const char *subnode_name);
+
+/**
+ * ofnode_first_subnode() - find the first subnode of a parent node
+ *
+ * @node:	valid reference to a valid parent node
+ * @return reference to the first subnode (which can be invalid if the parent
+ * node has no subnodes)
+ */
+ofnode ofnode_first_subnode(ofnode node);
+
+/**
+ * ofnode_next_subnode() - find the next sibling of a subnode
+ *
+ * @node:	valid reference to previous node (sibling)
+ * @return reference to the next subnode (which can be invalid if the node
+ * has no more siblings)
+ */
+ofnode ofnode_next_subnode(ofnode node);
+
+/**
+ * ofnode_get_name() - get the name of a node
+ *
+ * @node: valid node to look up
+ * @return name or node
+ */
+const char *ofnode_get_name(ofnode node);
+
+/**
+ * ofnode_read_size() - read the size of a property
+ *
+ * @node: node to check
+ * @propname: property to check
+ * @return size of property if present, or -EINVAL if not
+ */
+int ofnode_read_size(ofnode node, const char *propname);
+
+/**
+ * ofnode_stringlist_search() - find a string in a string list and return index
+ *
+ * Note that it is possible for this function to succeed on property values
+ * that are not NUL-terminated. That's because the function will stop after
+ * finding the first occurrence of @string. This can for example happen with
+ * small-valued cell properties, such as #address-cells, when searching for
+ * the empty string.
+ *
+ * @node: node to check
+ * @propname: name of the property containing the string list
+ * @string: string to look up in the string list
+ *
+ * @return:
+ *   the index of the string in the list of strings
+ *   -ENODATA if the property is not found
+ *   -EINVAL on some other error
+ */
+int ofnode_stringlist_search(ofnode node, const char *propname,
+			     const char *string);
+
+/**
+ * fdt_stringlist_get() - obtain the string at a given index in a string list
+ *
+ * Note that this will successfully extract strings from properties with
+ * non-NUL-terminated values. For example on small-valued cell properties
+ * this function will return the empty string.
+ *
+ * If non-NULL, the length of the string (on success) or a negative error-code
+ * (on failure) will be stored in the integer pointer to by lenp.
+ *
+ * @node: node to check
+ * @propname: name of the property containing the string list
+ * @index: index of the string to return
+ * @lenp: return location for the string length or an error code on failure
+ *
+ * @return:
+ *   length of string, if found or -ve error value if not found
+ */
+int ofnode_read_string_index(ofnode node, const char *propname, int index,
+			     const char **outp);
+
+/**
+ * ofnode_parse_phandle_with_args() - Find a node pointed by phandle in a list
+ *
+ * This function is useful to parse lists of phandles and their arguments.
+ * Returns 0 on success and fills out_args, on error returns appropriate
+ * errno value.
+ *
+ * Caller is responsible to call of_node_put() on the returned out_args->np
+ * pointer.
+ *
+ * Example:
+ *
+ * phandle1: node1 {
+ *	#list-cells = <2>;
+ * }
+ *
+ * phandle2: node2 {
+ *	#list-cells = <1>;
+ * }
+ *
+ * node3 {
+ *	list = <&phandle1 1 2 &phandle2 3>;
+ * }
+ *
+ * To get a device_node of the `node2' node you may call this:
+ * ofnode_parse_phandle_with_args(node3, "list", "#list-cells", 0, 1, &args);
+ *
+ * @node:	device tree node containing a list
+ * @list_name:	property name that contains a list
+ * @cells_name:	property name that specifies phandles' arguments count
+ * @cells_count: Cell count to use if @cells_name is NULL
+ * @index:	index of a phandle to parse out
+ * @out_args:	optional pointer to output arguments structure (will be filled)
+ * @return 0 on success (with @out_args filled out if not NULL), -ENOENT if
+ *	@list_name does not exist, -EINVAL if a phandle was not found,
+ *	@cells_name could not be found, the arguments were truncated or there
+ *	were too many arguments.
+ */
+int ofnode_parse_phandle_with_args(ofnode node, const char *list_name,
+				   const char *cells_name, int cell_count,
+				   int index,
+				   struct ofnode_phandle_args *out_args);
+
+/**
+ * ofnode_path() - find a node by full path
+ *
+ * @path: Full path to node, e.g. "/bus/spi@1"
+ * @return reference to the node found. Use ofnode_valid() to check if it exists
+ */
+ofnode ofnode_path(const char *path);
+
+/**
+ * ofnode_get_chosen_prop() - get the value of a chosen property
+ *
+ * This looks for a property within the /chosen node and returns its value
+ *
+ * @propname: Property name to look for
+ */
+const char *ofnode_get_chosen_prop(const char *propname);
+
+/**
+ * ofnode_get_chosen_node() - get the chosen node
+ *
+ * @return the chosen node if present, else ofnode_null()
+ */
+ofnode ofnode_get_chosen_node(const char *name);
+
+struct display_timing;
+/**
+ * ofnode_decode_display_timing() - decode display timings
+ *
+ * Decode display timings from the supplied 'display-timings' node.
+ * See doc/device-tree-bindings/video/display-timing.txt for binding
+ * information.
+ *
+ * @node	'display-timing' node containing the timing subnodes
+ * @index	Index number to read (0=first timing subnode)
+ * @config	Place to put timings
+ * @return 0 if OK, -FDT_ERR_NOTFOUND if not found
+ */
+int ofnode_decode_display_timing(ofnode node, int index,
+				 struct display_timing *config);
+
+/**
+ * ofnode_read_prop()- - read a node property
+ *
+ * @node: node to read
+ * @propname: property to read
+ * @lenp: place to put length on success
+ * @return pointer to property, or NULL if not found
+ */
+const u32 *ofnode_read_prop(ofnode node, const char *propname, int *lenp);
+
+/**
+ * ofnode_is_available() - check if a node is marked available
+ *
+ * @node: node to check
+ * @return true if node's 'status' property is "okay" (or is missing)
+ */
+bool ofnode_is_available(ofnode node);
+
+/**
+ * ofnode_get_addr_size() - get address and size from a property
+ *
+ * This does no address translation. It simply reads an property that contains
+ * an address and a size value, one after the other.
+ *
+ * @node: node to read from
+ * @propname: property to read
+ * @sizep: place to put size value (on success)
+ * @return address value, or FDT_ADDR_T_NONE on error
+ */
+phys_addr_t ofnode_get_addr_size(ofnode node, const char *propname,
+				 phys_size_t *sizep);
+
+/**
+ * ofnode_read_u8_array_ptr() - find an 8-bit array
+ *
+ * Look up a property in a node and return a pointer to its contents as a
+ * byte array of given length. The property must have at least enough data
+ * for the array (count bytes). It may have more, but this will be ignored.
+ * The data is not copied.
+ *
+ * @node	node to examine
+ * @propname	name of property to find
+ * @sz		number of array elements
+ * @return pointer to byte array if found, or NULL if the property is not
+ *		found or there is not enough data
+ */
+const uint8_t *ofnode_read_u8_array_ptr(ofnode node, const char *propname,
+					size_t sz);
+
+/**
+ * ofnode_read_pci_addr() - look up a PCI address
+ *
+ * Look at an address property in a node and return the PCI address which
+ * corresponds to the given type in the form of fdt_pci_addr.
+ * The property must hold one fdt_pci_addr with a lengh.
+ *
+ * @node	node to examine
+ * @type	pci address type (FDT_PCI_SPACE_xxx)
+ * @propname	name of property to find
+ * @addr	returns pci address in the form of fdt_pci_addr
+ * @return 0 if ok, -ENOENT if the property did not exist, -EINVAL if the
+ *		format of the property was invalid, -ENXIO if the requested
+ *		address type was not found
+ */
+int ofnode_read_pci_addr(ofnode node, enum fdt_pci_space type,
+			 const char *propname, struct fdt_pci_addr *addr);
+
+/**
+ * ofnode_read_addr_cells() - Get the number of address cells for a node
+ *
+ * This walks back up the tree to find the closest #address-cells property
+ * which controls the given node.
+ *
+ * @node: Node to check
+ * @return number of address cells this node uses
+ */
+int ofnode_read_addr_cells(ofnode node);
+
+/**
+ * ofnode_read_size_cells() - Get the number of size cells for a node
+ *
+ * This walks back up the tree to find the closest #size-cells property
+ * which controls the given node.
+ *
+ * @node: Node to check
+ * @return number of size cells this node uses
+ */
+int ofnode_read_size_cells(ofnode node);
+
+/**
+ * ofnode_pre_reloc() - check if a node should be bound before relocation
+ *
+ * Device tree nodes can be marked as needing-to-be-bound in the loader stages
+ * via special device tree properties.
+ *
+ * Before relocation this function can be used to check if nodes are required
+ * in either SPL or TPL stages.
+ *
+ * After relocation and jumping into the real U-Boot binary it is possible to
+ * determine if a node was bound in one of SPL/TPL stages.
+ *
+ * There are 3 settings currently in use
+ * -
+ * - u-boot,dm-pre-reloc: legacy and indicates any of TPL or SPL
+ *   Existing platforms only use it to indicate nodes needed in
+ *   SPL. Should probably be replaced by u-boot,dm-spl for
+ *   new platforms.
+ *
+ * @node: node to check
+ * @eturns true if node is needed in SPL/TL, false otherwise
+ */
+bool ofnode_pre_reloc(ofnode node);
+
 #endif