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-rw-r--r--drivers/of/resolver.c351
1 files changed, 351 insertions, 0 deletions
diff --git a/drivers/of/resolver.c b/drivers/of/resolver.c
new file mode 100644
index 0000000000..b278ab4338
--- /dev/null
+++ b/drivers/of/resolver.c
@@ -0,0 +1,351 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions for dealing with DT resolution
+ *
+ * Copyright (C) 2012 Pantelis Antoniou <panto@antoniou-consulting.com>
+ * Copyright (C) 2012 Texas Instruments Inc.
+ */
+
+#define pr_fmt(fmt) "OF: resolver: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+
+#include "of_private.h"
+
+static phandle live_tree_max_phandle(void)
+{
+ struct device_node *node;
+ phandle phandle;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&devtree_lock, flags);
+ phandle = 0;
+ for_each_of_allnodes(node) {
+ if (node->phandle != OF_PHANDLE_ILLEGAL &&
+ node->phandle > phandle)
+ phandle = node->phandle;
+ }
+ raw_spin_unlock_irqrestore(&devtree_lock, flags);
+
+ return phandle;
+}
+
+static void adjust_overlay_phandles(struct device_node *overlay,
+ int phandle_delta)
+{
+ struct device_node *child;
+ struct property *prop;
+ phandle phandle;
+
+ /* adjust node's phandle in node */
+ if (overlay->phandle != 0 && overlay->phandle != OF_PHANDLE_ILLEGAL)
+ overlay->phandle += phandle_delta;
+
+ /* copy adjusted phandle into *phandle properties */
+ for_each_property_of_node(overlay, prop) {
+
+ if (of_prop_cmp(prop->name, "phandle") &&
+ of_prop_cmp(prop->name, "linux,phandle"))
+ continue;
+
+ if (prop->length < 4)
+ continue;
+
+ phandle = be32_to_cpup(prop->value);
+ if (phandle == OF_PHANDLE_ILLEGAL)
+ continue;
+
+ *(__be32 *)prop->value = cpu_to_be32(overlay->phandle);
+ }
+
+ for_each_child_of_node(overlay, child)
+ adjust_overlay_phandles(child, phandle_delta);
+}
+
+static int update_usages_of_a_phandle_reference(struct device_node *overlay,
+ struct property *prop_fixup, phandle phandle)
+{
+ struct device_node *refnode;
+ struct property *prop;
+ char *value, *cur, *end, *node_path, *prop_name, *s;
+ int offset, len;
+ int err = 0;
+
+ value = kmemdup(prop_fixup->value, prop_fixup->length, GFP_KERNEL);
+ if (!value)
+ return -ENOMEM;
+
+ /* prop_fixup contains a list of tuples of path:property_name:offset */
+ end = value + prop_fixup->length;
+ for (cur = value; cur < end; cur += len + 1) {
+ len = strlen(cur);
+
+ node_path = cur;
+ s = strchr(cur, ':');
+ if (!s) {
+ err = -EINVAL;
+ goto err_fail;
+ }
+ *s++ = '\0';
+
+ prop_name = s;
+ s = strchr(s, ':');
+ if (!s) {
+ err = -EINVAL;
+ goto err_fail;
+ }
+ *s++ = '\0';
+
+ err = kstrtoint(s, 10, &offset);
+ if (err)
+ goto err_fail;
+
+ refnode = __of_find_node_by_full_path(of_node_get(overlay), node_path);
+ if (!refnode)
+ continue;
+
+ for_each_property_of_node(refnode, prop) {
+ if (!of_prop_cmp(prop->name, prop_name))
+ break;
+ }
+ of_node_put(refnode);
+
+ if (!prop) {
+ err = -ENOENT;
+ goto err_fail;
+ }
+
+ if (offset < 0 || offset + sizeof(__be32) > prop->length) {
+ err = -EINVAL;
+ goto err_fail;
+ }
+
+ *(__be32 *)(prop->value + offset) = cpu_to_be32(phandle);
+ }
+
+err_fail:
+ kfree(value);
+ return err;
+}
+
+/* compare nodes taking into account that 'name' strips out the @ part */
+static int node_name_cmp(const struct device_node *dn1,
+ const struct device_node *dn2)
+{
+ const char *n1 = kbasename(dn1->full_name);
+ const char *n2 = kbasename(dn2->full_name);
+
+ return of_node_cmp(n1, n2);
+}
+
+/*
+ * Adjust the local phandle references by the given phandle delta.
+ *
+ * Subtree @local_fixups, which is overlay node __local_fixups__,
+ * mirrors the fragment node structure at the root of the overlay.
+ *
+ * For each property in the fragments that contains a phandle reference,
+ * @local_fixups has a property of the same name that contains a list
+ * of offsets of the phandle reference(s) within the respective property
+ * value(s). The values at these offsets will be fixed up.
+ */
+static int adjust_local_phandle_references(struct device_node *local_fixups,
+ struct device_node *overlay, int phandle_delta)
+{
+ struct device_node *child, *overlay_child;
+ struct property *prop_fix, *prop;
+ int err, i, count;
+ unsigned int off;
+
+ if (!local_fixups)
+ return 0;
+
+ for_each_property_of_node(local_fixups, prop_fix) {
+
+ /* skip properties added automatically */
+ if (!of_prop_cmp(prop_fix->name, "name") ||
+ !of_prop_cmp(prop_fix->name, "phandle") ||
+ !of_prop_cmp(prop_fix->name, "linux,phandle"))
+ continue;
+
+ if ((prop_fix->length % 4) != 0 || prop_fix->length == 0)
+ return -EINVAL;
+ count = prop_fix->length / sizeof(__be32);
+
+ for_each_property_of_node(overlay, prop) {
+ if (!of_prop_cmp(prop->name, prop_fix->name))
+ break;
+ }
+
+ if (!prop)
+ return -EINVAL;
+
+ for (i = 0; i < count; i++) {
+ off = be32_to_cpu(((__be32 *)prop_fix->value)[i]);
+ if ((off + 4) > prop->length)
+ return -EINVAL;
+
+ be32_add_cpu(prop->value + off, phandle_delta);
+ }
+ }
+
+ /*
+ * These nested loops recurse down two subtrees in parallel, where the
+ * node names in the two subtrees match.
+ *
+ * The roots of the subtrees are the overlay's __local_fixups__ node
+ * and the overlay's root node.
+ */
+ for_each_child_of_node(local_fixups, child) {
+
+ for_each_child_of_node(overlay, overlay_child)
+ if (!node_name_cmp(child, overlay_child)) {
+ of_node_put(overlay_child);
+ break;
+ }
+
+ if (!overlay_child) {
+ of_node_put(child);
+ return -EINVAL;
+ }
+
+ err = adjust_local_phandle_references(child, overlay_child,
+ phandle_delta);
+ if (err) {
+ of_node_put(child);
+ return err;
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * of_resolve_phandles - Relocate and resolve overlay against live tree
+ *
+ * @overlay: Pointer to devicetree overlay to relocate and resolve
+ *
+ * Modify (relocate) values of local phandles in @overlay to a range that
+ * does not conflict with the live expanded devicetree. Update references
+ * to the local phandles in @overlay. Update (resolve) phandle references
+ * in @overlay that refer to the live expanded devicetree.
+ *
+ * Phandle values in the live tree are in the range of
+ * 1 .. live_tree_max_phandle(). The range of phandle values in the overlay
+ * also begin with at 1. Adjust the phandle values in the overlay to begin
+ * at live_tree_max_phandle() + 1. Update references to the phandles to
+ * the adjusted phandle values.
+ *
+ * The name of each property in the "__fixups__" node in the overlay matches
+ * the name of a symbol (a label) in the live tree. The values of each
+ * property in the "__fixups__" node is a list of the property values in the
+ * overlay that need to be updated to contain the phandle reference
+ * corresponding to that symbol in the live tree. Update the references in
+ * the overlay with the phandle values in the live tree.
+ *
+ * @overlay must be detached.
+ *
+ * Resolving and applying @overlay to the live expanded devicetree must be
+ * protected by a mechanism to ensure that multiple overlays are processed
+ * in a single threaded manner so that multiple overlays will not relocate
+ * phandles to overlapping ranges. The mechanism to enforce this is not
+ * yet implemented.
+ *
+ * Return: %0 on success or a negative error value on error.
+ */
+int of_resolve_phandles(struct device_node *overlay)
+{
+ struct device_node *child, *local_fixups, *refnode;
+ struct device_node *tree_symbols, *overlay_fixups;
+ struct property *prop;
+ const char *refpath;
+ phandle phandle, phandle_delta;
+ int err;
+
+ tree_symbols = NULL;
+
+ if (!overlay) {
+ pr_err("null overlay\n");
+ err = -EINVAL;
+ goto out;
+ }
+
+ if (!of_node_check_flag(overlay, OF_DETACHED)) {
+ pr_err("overlay not detached\n");
+ err = -EINVAL;
+ goto out;
+ }
+
+ phandle_delta = live_tree_max_phandle() + 1;
+ adjust_overlay_phandles(overlay, phandle_delta);
+
+ for_each_child_of_node(overlay, local_fixups)
+ if (of_node_name_eq(local_fixups, "__local_fixups__"))
+ break;
+
+ err = adjust_local_phandle_references(local_fixups, overlay, phandle_delta);
+ if (err)
+ goto out;
+
+ overlay_fixups = NULL;
+
+ for_each_child_of_node(overlay, child) {
+ if (of_node_name_eq(child, "__fixups__"))
+ overlay_fixups = child;
+ }
+
+ if (!overlay_fixups) {
+ err = 0;
+ goto out;
+ }
+
+ tree_symbols = of_find_node_by_path("/__symbols__");
+ if (!tree_symbols) {
+ pr_err("no symbols in root of device tree.\n");
+ err = -EINVAL;
+ goto out;
+ }
+
+ for_each_property_of_node(overlay_fixups, prop) {
+
+ /* skip properties added automatically */
+ if (!of_prop_cmp(prop->name, "name"))
+ continue;
+
+ err = of_property_read_string(tree_symbols,
+ prop->name, &refpath);
+ if (err) {
+ pr_err("node label '%s' not found in live devicetree symbols table\n",
+ prop->name);
+ goto out;
+ }
+
+ refnode = of_find_node_by_path(refpath);
+ if (!refnode) {
+ err = -ENOENT;
+ goto out;
+ }
+
+ phandle = refnode->phandle;
+ of_node_put(refnode);
+
+ err = update_usages_of_a_phandle_reference(overlay, prop, phandle);
+ if (err)
+ break;
+ }
+
+out:
+ if (err)
+ pr_err("overlay phandle fixup failed: %d\n", err);
+ of_node_put(tree_symbols);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(of_resolve_phandles);