mirror of
https://github.com/AsahiLinux/u-boot
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5ecba3ba40
Clarify the data structure so it is easier for people to understand, particularly the corner cases. Signed-off-by: Simon Glass <sjg@chromium.org>
144 lines
3.8 KiB
C
144 lines
3.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* Copyright (c) 2017 Google, Inc
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* Written by Simon Glass <sjg@chromium.org>
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*/
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#ifndef _DM_OF_H
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#define _DM_OF_H
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#include <asm/u-boot.h>
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#include <asm/global_data.h>
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/* integer value within a device tree property which references another node */
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typedef u32 phandle;
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/**
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* struct property: Device tree property
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*
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* @name: Property name
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* @length: Length of property in bytes
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* @value: Pointer to property value
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* @next: Pointer to next property, or NULL if none
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*/
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struct property {
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char *name;
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int length;
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void *value;
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struct property *next;
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};
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/**
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* struct device_node: Device tree node
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*
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* The top of this tree is typically gd->of_root which points to the root node.
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*
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* The head of the list of children for the root node (and any other node) is
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* in @child, with @sibling providing a link to the next child.
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*
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* Each child has a pointer to its parent in @parent.
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*
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* A node may have properties in which case the head of the list of properties
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* @properties pointers to the first one, with struct property->@next pointing
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* to the next one.
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*
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* @name: Node name, "" for the root node
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* @type: Node type (value of device_type property) or "<NULL>" if none
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* @phandle: Phandle value of this none, or 0 if none
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* @full_name: Full path to node, e.g. "/bus@1/spi@1100" ("/" for the root node)
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* @properties: Pointer to head of list of properties, or NULL if none
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* @parent: Pointer to parent node, or NULL if this is the root node
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* @child: Pointer to head of child node list, or NULL if no children
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* @sibling: Pointer to the next sibling node, or NULL if this is the last
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*/
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struct device_node {
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const char *name;
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const char *type;
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phandle phandle;
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const char *full_name;
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struct property *properties;
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struct device_node *parent;
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struct device_node *child;
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struct device_node *sibling;
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};
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#define OF_MAX_PHANDLE_ARGS 16
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/**
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* struct of_phandle_args - structure to hold phandle and arguments
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*
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* This is used when decoding a phandle in a device tree property. Typically
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* these look like this::
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*
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* wibble {
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* phandle = <5>;
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* };
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* ...
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* some-prop = <&wibble 1 2 3>
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*
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* Here &node is the phandle of the node 'wibble', i.e. 5. There are three
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* arguments: 1, 2, 3.
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*
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* So when decoding the phandle in some-prop, np will point to wibble,
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* args_count will be 3 and the three arguments will be in args.
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*
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* @np: Node that the phandle refers to
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* @args_count: Number of arguments
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* @args: Argument values
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*/
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struct of_phandle_args {
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struct device_node *np;
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int args_count;
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uint32_t args[OF_MAX_PHANDLE_ARGS];
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};
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DECLARE_GLOBAL_DATA_PTR;
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/**
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* of_live_active() - check if livetree is active
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*
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* @returns true if livetree is active, false it not
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*/
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static inline bool of_live_active(void)
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{
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return gd_of_root() != NULL;
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}
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#define OF_BAD_ADDR ((u64)-1)
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static inline const char *of_node_full_name(const struct device_node *np)
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{
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return np ? np->full_name : "<no-node>";
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}
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/* Default #address and #size cells */
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#if !defined(OF_ROOT_NODE_ADDR_CELLS_DEFAULT)
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#define OF_ROOT_NODE_ADDR_CELLS_DEFAULT 2
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#define OF_ROOT_NODE_SIZE_CELLS_DEFAULT 1
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#endif
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/* Default string compare functions */
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#if !defined(of_compat_cmp)
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#define of_compat_cmp(s1, s2, l) strcasecmp((s1), (s2))
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#define of_prop_cmp(s1, s2) strcmp((s1), (s2))
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#define of_node_cmp(s1, s2) strcasecmp((s1), (s2))
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#endif
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/* Helper to read a big number; size is in cells (not bytes) */
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static inline u64 of_read_number(const __be32 *cell, int size)
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{
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u64 r = 0;
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while (size--)
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r = (r << 32) | be32_to_cpu(*(cell++));
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return r;
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}
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/* Like of_read_number, but we want an unsigned long result */
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static inline unsigned long of_read_ulong(const __be32 *cell, int size)
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{
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/* toss away upper bits if unsigned long is smaller than u64 */
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return of_read_number(cell, size);
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}
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#endif
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