dm: Add a function to create a 'live' device tree

This function converts the flat device tree into a hierarchical one with
C structures and pointers. This is easier to access.

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

include/of_live.h

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2017 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ *
+ * Support for a 'live' (as opposed to flat) device tree
+ */
+
+#ifndef _OF_LIVE_H
+#define _OF_LIVE_H
+
+struct device_node;
+
+/**
+ * of_live_build() - build a live (hierarchical) tree from a flat DT
+ *
+ * @fdt_blob: Input tree to convert
+ * @rootp: Returns live tree that was created
+ * @return 0 if OK, -ve on error
+ */
+int of_live_build(const void *fdt_blob, struct device_node **rootp);
+
+#endif

lib/Makefile

@@ -15,6 +15,7 @@ obj-$(CONFIG_ZLIB) += zlib/
 obj-$(CONFIG_BZIP2) += bzip2/
 obj-$(CONFIG_TIZEN) += tizen/
 obj-$(CONFIG_FIT) += libfdt/
+obj-$(CONFIG_OF_LIVE) += of_live.o
 obj-$(CONFIG_CMD_DHRYSTONE) += dhry/
 
 obj-$(CONFIG_AES) += aes.o

lib/of_live.c

@@ -0,0 +1,333 @@
+/*
+ * Copyright 2009 Benjamin Herrenschmidt, IBM Corp
+ * benh@kernel.crashing.org
+ *
+ * Based on parts of drivers/of/fdt.c from Linux v4.9
+ * Modifications for U-Boot
+ * Copyright (c) 2017 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <libfdt.h>
+#include <of_live.h>
+#include <malloc.h>
+#include <dm/of_access.h>
+#include <linux/err.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static void *unflatten_dt_alloc(void **mem, unsigned long size,
+				unsigned long align)
+{
+	void *res;
+
+	*mem = PTR_ALIGN(*mem, align);
+	res = *mem;
+	*mem += size;
+
+	return res;
+}
+
+/**
+ * unflatten_dt_node() - Alloc and populate a device_node from the flat tree
+ * @blob: The parent device tree blob
+ * @mem: Memory chunk to use for allocating device nodes and properties
+ * @poffset: pointer to node in flat tree
+ * @dad: Parent struct device_node
+ * @nodepp: The device_node tree created by the call
+ * @fpsize: Size of the node path up at t05he current depth.
+ * @dryrun: If true, do not allocate device nodes but still calculate needed
+ * memory size
+ */
+static void *unflatten_dt_node(const void *blob, void *mem, int *poffset,
+			       struct device_node *dad,
+			       struct device_node **nodepp,
+			       unsigned long fpsize, bool dryrun)
+{
+	const __be32 *p;
+	struct device_node *np;
+	struct property *pp, **prev_pp = NULL;
+	const char *pathp;
+	int l;
+	unsigned int allocl;
+	static int depth;
+	int old_depth;
+	int offset;
+	int has_name = 0;
+	int new_format = 0;
+
+	pathp = fdt_get_name(blob, *poffset, &l);
+	if (!pathp)
+		return mem;
+
+	allocl = ++l;
+
+	/*
+	 * version 0x10 has a more compact unit name here instead of the full
+	 * path. we accumulate the full path size using "fpsize", we'll rebuild
+	 * it later. We detect this because the first character of the name is
+	 * not '/'.
+	 */
+	if ((*pathp) != '/') {
+		new_format = 1;
+		if (fpsize == 0) {
+			/*
+			 * root node: special case. fpsize accounts for path
+			 * plus terminating zero. root node only has '/', so
+			 * fpsize should be 2, but we want to avoid the first
+			 * level nodes to have two '/' so we use fpsize 1 here
+			 */
+			fpsize = 1;
+			allocl = 2;
+			l = 1;
+			pathp = "";
+		} else {
+			/*
+			 * account for '/' and path size minus terminal 0
+			 * already in 'l'
+			 */
+			fpsize += l;
+			allocl = fpsize;
+		}
+	}
+
+	np = unflatten_dt_alloc(&mem, sizeof(struct device_node) + allocl,
+				__alignof__(struct device_node));
+	if (!dryrun) {
+		char *fn;
+
+		fn = (char *)np + sizeof(*np);
+		np->full_name = fn;
+		if (new_format) {
+			/* rebuild full path for new format */
+			if (dad && dad->parent) {
+				strcpy(fn, dad->full_name);
+#ifdef DEBUG
+				if ((strlen(fn) + l + 1) != allocl) {
+					debug("%s: p: %d, l: %d, a: %d\n",
+					      pathp, (int)strlen(fn), l,
+					      allocl);
+				}
+#endif
+				fn += strlen(fn);
+			}
+			*(fn++) = '/';
+		}
+		memcpy(fn, pathp, l);
+
+		prev_pp = &np->properties;
+		if (dad != NULL) {
+			np->parent = dad;
+			np->sibling = dad->child;
+			dad->child = np;
+		}
+	}
+	/* process properties */
+	for (offset = fdt_first_property_offset(blob, *poffset);
+	     (offset >= 0);
+	     (offset = fdt_next_property_offset(blob, offset))) {
+		const char *pname;
+		int sz;
+
+		p = fdt_getprop_by_offset(blob, offset, &pname, &sz);
+		if (!p) {
+			offset = -FDT_ERR_INTERNAL;
+			break;
+		}
+
+		if (pname == NULL) {
+			debug("Can't find property name in list !\n");
+			break;
+		}
+		if (strcmp(pname, "name") == 0)
+			has_name = 1;
+		pp = unflatten_dt_alloc(&mem, sizeof(struct property),
+					__alignof__(struct property));
+		if (!dryrun) {
+			/*
+			 * We accept flattened tree phandles either in
+			 * ePAPR-style "phandle" properties, or the
+			 * legacy "linux,phandle" properties.  If both
+			 * appear and have different values, things
+			 * will get weird.  Don't do that. */
+			if ((strcmp(pname, "phandle") == 0) ||
+			    (strcmp(pname, "linux,phandle") == 0)) {
+				if (np->phandle == 0)
+					np->phandle = be32_to_cpup(p);
+			}
+			/*
+			 * And we process the "ibm,phandle" property
+			 * used in pSeries dynamic device tree
+			 * stuff */
+			if (strcmp(pname, "ibm,phandle") == 0)
+				np->phandle = be32_to_cpup(p);
+			pp->name = (char *)pname;
+			pp->length = sz;
+			pp->value = (__be32 *)p;
+			*prev_pp = pp;
+			prev_pp = &pp->next;
+		}
+	}
+	/*
+	 * with version 0x10 we may not have the name property, recreate
+	 * it here from the unit name if absent
+	 */
+	if (!has_name) {
+		const char *p1 = pathp, *ps = pathp, *pa = NULL;
+		int sz;
+
+		while (*p1) {
+			if ((*p1) == '@')
+				pa = p1;
+			if ((*p1) == '/')
+				ps = p1 + 1;
+			p1++;
+		}
+		if (pa < ps)
+			pa = p1;
+		sz = (pa - ps) + 1;
+		pp = unflatten_dt_alloc(&mem, sizeof(struct property) + sz,
+					__alignof__(struct property));
+		if (!dryrun) {
+			pp->name = "name";
+			pp->length = sz;
+			pp->value = pp + 1;
+			*prev_pp = pp;
+			prev_pp = &pp->next;
+			memcpy(pp->value, ps, sz - 1);
+			((char *)pp->value)[sz - 1] = 0;
+			debug("fixed up name for %s -> %s\n", pathp,
+			      (char *)pp->value);
+		}
+	}
+	if (!dryrun) {
+		*prev_pp = NULL;
+		np->name = of_get_property(np, "name", NULL);
+		np->type = of_get_property(np, "device_type", NULL);
+
+		if (!np->name)
+			np->name = "<NULL>";
+		if (!np->type)
+			np->type = "<NULL>";	}
+
+	old_depth = depth;
+	*poffset = fdt_next_node(blob, *poffset, &depth);
+	if (depth < 0)
+		depth = 0;
+	while (*poffset > 0 && depth > old_depth)
+		mem = unflatten_dt_node(blob, mem, poffset, np, NULL,
+					fpsize, dryrun);
+
+	if (*poffset < 0 && *poffset != -FDT_ERR_NOTFOUND) {
+		debug("unflatten: error %d processing FDT\n", *poffset);
+		return NULL;
+	}
+
+	/*
+	 * Reverse the child list. Some drivers assumes node order matches .dts
+	 * node order
+	 */
+	if (!dryrun && np->child) {
+		struct device_node *child = np->child;
+		np->child = NULL;
+		while (child) {
+			struct device_node *next = child->sibling;
+
+			child->sibling = np->child;
+			np->child = child;
+			child = next;
+		}
+	}
+
+	if (nodepp)
+		*nodepp = np;
+
+	return mem;
+}
+
+/**
+ * unflatten_device_tree() - create tree of device_nodes from flat blob
+ *
+ * unflattens a device-tree, creating the
+ * tree of struct device_node. It also fills the "name" and "type"
+ * pointers of the nodes so the normal device-tree walking functions
+ * can be used.
+ * @blob: The blob to expand
+ * @mynodes: The device_node tree created by the call
+ * @return 0 if OK, -ve on error
+ */
+static int unflatten_device_tree(const void *blob,
+				 struct device_node **mynodes)
+{
+	unsigned long size;
+	int start;
+	void *mem;
+
+	debug(" -> unflatten_device_tree()\n");
+
+	if (!blob) {
+		debug("No device tree pointer\n");
+		return -EINVAL;
+	}
+
+	debug("Unflattening device tree:\n");
+	debug("magic: %08x\n", fdt_magic(blob));
+	debug("size: %08x\n", fdt_totalsize(blob));
+	debug("version: %08x\n", fdt_version(blob));
+
+	if (fdt_check_header(blob)) {
+		debug("Invalid device tree blob header\n");
+		return -EINVAL;
+	}
+
+	/* First pass, scan for size */
+	start = 0;
+	size = (unsigned long)unflatten_dt_node(blob, NULL, &start, NULL, NULL,
+						0, true);
+	size = ALIGN(size, 4);
+
+	debug("  size is %lx, allocating...\n", size);
+
+	/* Allocate memory for the expanded device tree */
+	mem = malloc(size + 4);
+	memset(mem, '\0', size);
+
+	*(__be32 *)(mem + size) = cpu_to_be32(0xdeadbeef);
+
+	debug("  unflattening %p...\n", mem);
+
+	/* Second pass, do actual unflattening */
+	start = 0;
+	unflatten_dt_node(blob, mem, &start, NULL, mynodes, 0, false);
+	if (be32_to_cpup(mem + size) != 0xdeadbeef) {
+		debug("End of tree marker overwritten: %08x\n",
+		      be32_to_cpup(mem + size));
+		return -ENOSPC;
+	}
+
+	debug(" <- unflatten_device_tree()\n");
+
+	return 0;
+}
+
+int of_live_build(const void *fdt_blob, struct device_node **rootp)
+{
+	int ret;
+
+	debug("%s: start\n", __func__);
+	ret = unflatten_device_tree(fdt_blob, rootp);
+	if (ret) {
+		debug("Failed to create live tree: err=%d\n", ret);
+		return ret;
+	}
+	ret = of_alias_scan();
+	if (ret) {
+		debug("Failed to scan live tree aliases: err=%d\n", ret);
+		return ret;
+	}
+	debug("%s: stop\n", __func__);
+
+	return ret;
+}