Browse Source

dm: core: Add livetree definitions

Add a Kconfig option to enable a live device tree, built at run time from
the flat tree. Also add structure definitions and a root node.

Signed-off-by: Simon Glass <sjg@chromium.org>
tags/2020-06-01
Simon Glass 4 years ago
parent
commit
5e060d8bcc
3 changed files with 120 additions and 0 deletions
  1. +11
    -0
      dts/Kconfig
  2. +3
    -0
      include/asm-generic/global_data.h
  3. +106
    -0
      include/dm/of.h

+ 11
- 0
dts/Kconfig View File

@@ -32,6 +32,17 @@ config SPL_OF_CONTROL
which is not enough to support device tree. Enable this option to
allow such boards to be supported by U-Boot SPL.

config OF_LIVE
bool "Enable use of a live tree"
depends on OF_CONTROL
help
Normally U-Boot uses a flat device tree which saves space and
avoids the need to unpack the tree before use. However a flat
tree does not support modifcation from within U-Boot since it
can invalidate driver-model device tree offsets. This option
enables a live tree which is available after relocation,
and can be adjusted as needed.

choice
prompt "Provider of DTB for DT control"
depends on OF_CONTROL


+ 3
- 0
include/asm-generic/global_data.h View File

@@ -72,6 +72,9 @@ typedef struct global_data {
const void *fdt_blob; /* Our device tree, NULL if none */
void *new_fdt; /* Relocated FDT */
unsigned long fdt_size; /* Space reserved for relocated FDT */
#ifdef CONFIG_OF_LIVE
struct device_node *of_root;
#endif
struct jt_funcs *jt; /* jump table */
char env_buf[32]; /* buffer for getenv() before reloc. */
#ifdef CONFIG_TRACE


+ 106
- 0
include/dm/of.h View File

@@ -0,0 +1,106 @@
/*
* Copyright (c) 2017 Google, Inc
* Written by Simon Glass <sjg@chromium.org>
*
* SPDX-License-Identifier: GPL-2.0+
*/

#ifndef _DM_OF_H
#define _DM_OF_H

#include <asm/u-boot.h>
#include <asm/global_data.h>

/* integer value within a device tree property which references another node */
typedef u32 phandle;

/**
* struct property: Device tree property
*
* @name: Property name
* @length: Length of property in bytes
* @value: Pointer to property value
* @next: Pointer to next property, or NULL if none
*/
struct property {
char *name;
int length;
void *value;
struct property *next;
};

/**
* struct device_node: Device tree node
*
* @name: Node name
* @type: Node type (value of device_type property) or "<NULL>" if none
* @phandle: Phandle value of this none, or 0 if none
* @full_name: Full path to node, e.g. "/bus@1/spi@1100"
* @properties: Pointer to head of list of properties, or NULL if none
* @parent: Pointer to parent node, or NULL if this is the root node
* @child: Pointer to head of child node list, or NULL if no children
* @sibling: Pointer to the next sibling node, or NULL if this is the last
*/
struct device_node {
const char *name;
const char *type;
phandle phandle;
const char *full_name;

struct property *properties;
struct device_node *parent;
struct device_node *child;
struct device_node *sibling;
};

#define OF_MAX_PHANDLE_ARGS 16

/**
* struct of_phandle_args - structure to hold phandle and arguments
*
* This is used when decoding a phandle in a device tree property. Typically
* these look like this:
*
* wibble {
* phandle = <5>;
* };
*
* ...
* some-prop = <&wibble 1 2 3>
*
* Here &node is the phandle of the node 'wibble', i.e. 5. There are three
* arguments: 1, 2, 3.
*
* So when decoding the phandle in some-prop, np will point to wibble,
* args_count will be 3 and the three arguments will be in args.
*
* @np: Node that the phandle refers to
* @args_count: Number of arguments
* @args: Argument values
*/
struct of_phandle_args {
struct device_node *np;
int args_count;
uint32_t args[OF_MAX_PHANDLE_ARGS];
};

DECLARE_GLOBAL_DATA_PTR;

/**
* of_live_active() - check if livetree is active
*
* @returns true if livetree is active, false it not
*/
#ifdef CONFIG_OF_LIVE
static inline bool of_live_active(void)
{
return gd->of_root != NULL;
}
#else
static inline bool of_live_active(void)
{
return false;
}
#endif

#endif