Device Tree API#

Public API#

group Device tree

Typedefs

typedef u32 dt_node_t#: A node is an offset from the start of fdt with FDT_BEGIN_NODE.

typedef u32 dt_prop_t#: A property is an offset from the start of fdt with FDT_PROP.

Functions

error_t dt_init(const void *fdt, fdt_t *obj)#

Read the header at fdt and set fields of obj.

Note

If an error occurs, fdt_buffer of obj is set to an invalid buffer.

Parameters:

fdt – Pointer to the flattened device tree data.
obj – Pointer to the fdt_t structure to initialize.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args
ERR_NOT_VALID – if the FDT is invalid or unsupported

void dt_reset(fdt_t *obj)#

Reset properties of obj.

Parameters:: obj – Pointer to the fdt_t structure to reset.

error_t dt_get_node_in_subtree_by_path(const fdt_t *fdt, dt_node_t node, const char *node_path, dt_node_t *nodeOUT)#

Get a node in a subtree of fdt, leave as 0 for global search.

Parameters:

fdt – Pointer to the fdt object.
node – The node of which subtree to search, leave as 0 for global search.
node_path – Path to the node.
nodeOUT – [out] Found node.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args
ERR_NOT_VALID – if the FDT is invalid
ERR_NOT_FOUND – if no node found
ERR_OUT_OF_BOUNDS – if search went out of bounds

error_t dt_get_node_by_path(const fdt_t *fdt, const char *node_path, dt_node_t *nodeOUT)#

Get a node globally in fdt.

Parameters:

fdt – Pointer to the fdt object.
node_path – Path to the node.
nodeOUT – [out] Found node.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args
ERR_NOT_VALID – if the FDT is invalid
ERR_NOT_FOUND – if no node found
ERR_OUT_OF_BOUNDS – if search went out of bounds

error_t dt_get_node_child(const fdt_t *fdt, dt_node_t node, dt_node_t *nodeOUT)#

Get a node’s first child in fdt.

Parameters:

fdt – Pointer to the fdt object.
node – The parent node.
nodeOUT – [out] Child node.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args
ERR_NOT_VALID – if the FDT is invalid
ERR_NOT_FOUND – if no node found
ERR_OUT_OF_BOUNDS – if search went out of bounds

error_t dt_get_node_sibling(const fdt_t *fdt, dt_node_t node, dt_node_t *nodeOUT)#

Get a node’s next sibling in fdt.

Parameters:

fdt – Pointer to the fdt object.
node – The node to get the sibling of.
nodeOUT – [out] Sibling node.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args
ERR_NOT_VALID – if the FDT is invalid
ERR_NOT_FOUND – if no node found
ERR_OUT_OF_BOUNDS – if search went out of bounds

error_t dt_get_node_name(const fdt_t *fdt, dt_node_t node, buffer_t *bufOUT)#

Get a node’s name as a buffer in fdt.

Parameters:

fdt – Pointer to the fdt object.
node – The node to get the name of.
bufOUT – [out] Buffer with the name.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args or misaligned node
ERR_NOT_VALID – if the FDT is invalid

error_t dt_get_node_name_ptr(const fdt_t *fdt, dt_node_t node, const char **ptrOUT)#

Get a node’s name as a pointer in fdt.

Parameters:

fdt – Pointer to the fdt object.
node – The node to get the name of.
ptrOUT – [out] Pointer to the name.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args or misaligned node
ERR_NOT_VALID – if the FDT is invalid

error_t dt_get_prop_by_name(const fdt_t *fdt, dt_node_t node, const char *prop_name, dt_prop_t *propOUT)#

Get a node’s prop_name property in fdt.

Parameters:

fdt – Pointer to the fdt object.
node – The node to search in.
prop_name – Name of the property.
propOUT – [out] Property.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args or misaligned node
ERR_NOT_VALID – if the FDT is invalid
ERR_NOT_FOUND – if no prop found
ERR_OUT_OF_BOUNDS – if search went out of bounds

error_t dt_get_first_prop(const fdt_t *fdt, dt_node_t node, dt_prop_t *propOUT)#

Get a node’s first property in fdt.

Parameters:

fdt – Pointer to the fdt object.
node – The node to get the first property of.
propOUT – [out] First property.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args or misaligned node
ERR_NOT_VALID – if the FDT is invalid
ERR_NOT_FOUND – if no prop found
ERR_OUT_OF_BOUNDS – if search went out of bounds

error_t dt_get_next_prop(const fdt_t *fdt, dt_prop_t prop, dt_prop_t *propOUT)#

Get a node’s next property after prop in fdt.

Parameters:

fdt – Pointer to the fdt object.
prop – The current property.
propOUT – [out] Next property.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args or misaligned prop
ERR_NOT_VALID – if the FDT is invalid
ERR_NOT_FOUND – if no prop found
ERR_OUT_OF_BOUNDS – if search went out of bounds

error_t dt_get_prop_name(const fdt_t *fdt, dt_prop_t prop, buffer_t *bufOUT)#

Get a prop’s name as a buffer in fdt.

Parameters:

fdt – Pointer to the fdt object.
prop – The property to get the name of.
bufOUT – [out] Buffer with the name.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args or misaligned prop
ERR_NOT_VALID – if the FDT is invalid

error_t dt_get_prop_name_ptr(const fdt_t *fdt, dt_prop_t prop, const char **ptrOUT)#

Get a prop’s name as a pointer in fdt.

Parameters:

fdt – Pointer to the fdt object.
prop – The property to get the name of.
ptrOUT – [out] Pointer to the name.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args or misaligned prop
ERR_NOT_VALID – if the FDT is invalid

error_t dt_get_prop_buffer(const fdt_t *fdt, dt_prop_t prop, buffer_t *bufOUT)#

Get a buffer for prop’s data.

Parameters:

fdt – Pointer to the fdt object.
prop – The property to get the data of.
bufOUT – [out] Buffer with the data.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args
ERR_NOT_VALID – if the FDT is invalid

struct fdt_t#

#include <dt.h>

Flattened device tree structure.

Public Members

buffer_t fdt_buffer#: Buffer containing the FDT data.

dt_node_t root_node#: Root node offset.

u32 total_size#: Total size of the FDT.

u32 struct_off#: Structure block offset.

u32 strings_off#: Strings block offset.

u32 struct_size#: Structure block size.

u32 fdt_version#: FDT version.

Internals#

group Dt_internal

Defines

FDT_MAGIC#: FDT magic number.

FDT_OFF_MAGIC#: Offset to magic number.

FDT_OFF_TOTAL_SIZE#: Offset to total size.

FDT_OFF_OFF_DT_STRUCT#: Offset to structure block offset.

FDT_OFF_OFF_DT_STRINGS#: Offset to strings block offset.

FDT_OFF_MEM_RSVMAP#: Offset to memory reservation map.

FDT_OFF_VERSION#: Offset to version.

FDT_OFF_LAST_COMP_VERSION#: Offset to last compatible version.

FDT_OFF_BOOT_CPUID_PHYS#: Offset to boot CPU physical ID.

FDT_OFF_SIZE_DT_STRINGS#: Offset to strings block size.

FDT_OFF_SIZE_DT_STRUCT#: Offset to structure block size.

FDT_COMPATIBLE_VERSION#: Minimum compatible FDT version.

Enums

enum fdt_token_t#

FDT token values.

Values:

enumerator FDT_BEGIN_NODE#: Begin node token.

enumerator FDT_END_NODE#: End node token.

enumerator FDT_PROP#: Property token.

enumerator FDT_NOP#: Nop token.

enumerator FDT_END#: End of structure block token.

Functions

error_t dt_skip_node_name(const fdt_t *fdt, dt_node_t node, u32 *offsetOUT)#

Skip node’s tag and name and output first aligned offset after them.

Parameters:

fdt – Pointer to the flattened device tree.
node – The device tree node.
offsetOUT – [out] First aligned offset after the node.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args or misaligned node
ERR_NOT_VALID – if the FDT is invalid

error_t dt_skip_node_properties(const fdt_t *fdt, u32 offset, u32 *offsetOUT)#

Skip node’s properties starting at offset (if they exist) and output first aligned offset after them.

Parameters:

fdt – Pointer to the flattened device tree.
offset – The offset to start skipping properties from.
offsetOUT – [out] First aligned offset after properties at offset.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args
ERR_NOT_VALID – if the FDT is invalid

error_t dt_skip_node_header(const fdt_t *fdt, dt_node_t node, u32 *offsetOUT)#

Skip node’s tag, name and properties and output first aligned offset after them.

Parameters:

fdt – Pointer to the flattened device tree.
node – The device tree node.
offsetOUT – [out] First aligned offset after the node.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args or misaligned node
ERR_NOT_VALID – if the FDT is invalid

error_t dt_skip_nested_nodes(const fdt_t *fdt, dt_node_t nested_node, dt_node_t *nodeOUT)#

Skip an overarching node’s nested nodes starting at the start of the first nested node.

Parameters:

fdt – Pointer to the flattened device tree.
nested_node – The first nested node to start skipping from.
nodeOUT – [out] First non-nested node after the nested_node.

Return values:

ERR_NONE – on success
ERR_BAD_ARG – on nullptr args or misaligned nested_node
ERR_NOT_VALID – if the FDT is invalid

Device Tree API#

Public API#

Internals#

This Page