fdt.c File Reference

Implementation of Device Tree Blob (FDT) parsing and validation functions. More...

#include "fdt/fdt.h"
#include "utils/kprintf.h"
#include <libfdt.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

Include dependency graph for fdt.c:

Functions
bool	check_fdt (const void *ptr)
	Check the validity of the Device Tree Blob (FDT).
int	get_mem (const void *fdt, memory_map_t *mmap)
	Scans the FDT for memory nodes and populates the provided map.
int	get_intc_node_offset (const void *fdt)
	Retrieves a pointer to the interrupt controller node in the FDT.
bool	fdt_is_error (int offset)
	Checks if the given FDT offset represents an error.
char *	get_compatible_string (const void *fdt, int node_offset)
	Retrieves the compatible string for a given node.
bool	get_reg_property (const void *fdt, int node_offset, memory_map_t *reg_map)
	Retrieves the register property for a given node.
int	get_intr_property (const void *fdt, int node_offset, interrupt_t *out_intr_array, size_t out_intr_array_len)
	Retrieves the interrupt property for a given node.
int	get_nodes_by_compatible (const void *fdt, const char *compatible, int *out_node_offsets, size_t out_node_offsets_len)
	Finds all nodes in the FDT matching a given "compatible" string.

Detailed Description

Implementation of Device Tree Blob (FDT) parsing and validation functions.

Validates the FDT header, extracts memory map entries, and exposes kernel helpers for consuming device tree data.

Author

Abhin Parekadan Jose

Date

2026-05-16

Function Documentation

check_fdt()

bool check_fdt

(

const void *

ptr

)

Check the validity of the Device Tree Blob (FDT).

Parameters

ptr	Pointer to the FDT in memory.

Returns

true if the FDT is valid, false otherwise.

fdt_is_error()

bool fdt_is_error

(

int

offset

)

Checks if the given FDT offset represents an error.

Parameters

offset

The FDT offset to check.

Returns

true if the offset is an error code, false otherwise.

get_compatible_string()

char * get_compatible_string	(	const void *	fdt,
		int	node_offset
	)

Retrieves the compatible string for a given node.

Parameters

fdt	Pointer to the FDT header in memory.
node_offset	Offset of the node for which to retrieve the compatible string.

Returns

Pointer to the compatible string, or NULL if not found.

get_intc_node_offset()

int get_intc_node_offset

(

const void *

fdt

)

Retrieves a pointer to the interrupt controller node in the FDT.

Parameters

fdt	Pointer to the FDT header in memory.

Returns

Offset of the interrupt controller node, or a negative libfdt error code if not found.

get_intr_property()

int get_intr_property	(	const void *	fdt,
		int	node_offset,
		interrupt_t *	out_intr_array,
		size_t	out_intr_array_len
	)

Retrieves the interrupt property for a given node.

Parameters

fdt	Pointer to the FDT header in memory.
node_offset	Offset of the node for which to retrieve the interrupt property.
out_intr_array	Array to be populated with the parsed interrupt specifiers.
out_intr_array_len	Number of elements available in out_intr_array.

Returns

The number of interrupt entries parsed (capped at out_intr_array_len), or a negative libfdt error code on failure.

get_mem()

int get_mem	(	const void *	fdt,
		memory_map_t *	mmap
	)

Scans the FDT for memory nodes and populates the provided map.

This function searches the FDT for nodes with device_type = "memory", respects the root node's #address-cells and #size-cells, and handles both 32-bit and 64-bit address formats.

Parameters

fdt	Pointer to the FDT header in memory.
mmap	Pointer to a memory_map_t structure to be populated.

Returns

0 on success, or a negative libfdt error code on failure.

get_nodes_by_compatible()

int get_nodes_by_compatible	(	const void *	fdt,
		const char *	compatible,
		int *	out_node_offsets,
		size_t	out_node_offsets_len
	)

Finds all nodes in the FDT matching a given "compatible" string.

Parameters

fdt	Pointer to the FDT header in memory.
compatible	Compatible string to search for.
out_node_offsets	Array to be populated with the offsets of matching nodes.
out_node_offsets_len	Number of elements available in out_node_offsets.

Returns

The number of matching nodes found (capped at out_node_offsets_len), or a negative libfdt error code on failure.

get_reg_property()

bool get_reg_property	(	const void *	fdt,
		int	node_offset,
		memory_map_t *	reg_map
	)

Retrieves the register property for a given node.

Parameters

fdt	Pointer to the FDT header in memory.
node_offset	Offset of the node for which to retrieve the register property.
reg_map	Pointer to a memory_map_t structure to be populated with register information.

Returns

true if the register property is found and successfully parsed, false otherwise.