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