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reserved-memory: Introduce support for reserved-memory node
Introduce a set of header files to be able to define and declare sections and regions in the linker script. Introduce also DT helpers to retrieve data back. Signed-off-by: Carlo Caione <[email protected]>
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‎dts/bindings/reserved-memory/reserved-memory.yaml‎

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description: |
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Reserved memory - Each child of the reserved-memory node specifies one or
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more regions of reserved memory. Regions in the /reserved-memory node may be
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referenced by other device nodes by adding a memory-region property to the
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device node.
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compatible: "reserved-memory"
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include:
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- name: base.yaml
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property-allowlist: ['#address-cells', '#size-cells']
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child-binding:
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description: Regions
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properties:
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label:
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type: string
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required: false
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description: Human readable string describing the device (used as device_get_binding() argument)
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reg:
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type: array
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description: register space
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required: true

‎include/devicetree/memory.h‎

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/**
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* @file
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* @brief reserved-memory Devicetree macro public API header file.
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*/
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/*
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* Copyright (c) 2021 Carlo Caione <[email protected]>
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#ifndef ZEPHYR_INCLUDE_DEVICETREE_MEMORY_H_
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#define ZEPHYR_INCLUDE_DEVICETREE_MEMORY_H_
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @defgroup devicetree-reserved Devicetree reserved-memory API
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* @ingroup devicetree
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* @{
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*/
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/**
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* @brief Get the pointer to the reserved-memory region
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*
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* Example devicetree fragment:
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*
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* reserved: reserved-memory {
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* compatible = "reserved-memory";
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* ...
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* n: node {
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* reg = <0x42000000 0x1000>;
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* };
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* };
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*
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* Example usage:
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*
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* DT_RESERVED_MEM_GET_PTR(DT_NODELABEL(n)) // (uint8_t *) 0x42000000
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*
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* @param node_id node identifier
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* @return pointer to the beginning of the reserved-memory region
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*/
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#define DT_RESERVED_MEM_GET_PTR(node_id) _DT_RESERVED_START(node_id)
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/**
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* @brief Get the size of the reserved-memory region
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*
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* Example devicetree fragment:
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*
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* reserved: reserved-memory {
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* compatible = "reserved-memory";
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* ...
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* n: node {
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* reg = <0x42000000 0x1000>;
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* };
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* };
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*
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* Example usage:
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*
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* DT_RESERVED_MEM_GET_SIZE(DT_NODELABEL(n)) // 0x1000
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*
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* @param node_id node identifier
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* @return the size of the reserved-memory region
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*/
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#define DT_RESERVED_MEM_GET_SIZE(node_id) DT_REG_SIZE(node_id)
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/**
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* @brief Get the pointer to the reserved-memory region from a memory-reserved
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* phandle
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*
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* Example devicetree fragment:
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*
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* reserved: reserved-memory {
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* compatible = "reserved-memory";
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* ...
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* res0: res {
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* reg = <0x42000000 0x1000>;
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* label = "res0";
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* };
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* };
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*
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* n: node {
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* memory-region = <&res0>;
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* };
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*
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* Example usage:
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*
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* DT_RESERVED_MEM_GET_PTR_BY_PHANDLE(DT_NODELABEL(n), memory_region) // (uint8_t *) 0x42000000
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*
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* @param node_id node identifier
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* @param ph phandle to reserved-memory region
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*
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* @return pointer to the beginning of the reserved-memory region
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*/
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#define DT_RESERVED_MEM_GET_PTR_BY_PHANDLE(node_id, ph) \
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DT_RESERVED_MEM_GET_PTR(DT_PHANDLE(node_id, ph))
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/**
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* @brief Get the size of the reserved-memory region from a memory-reserved
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* phandle
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*
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* Example devicetree fragment:
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*
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* reserved: reserved-memory {
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* compatible = "reserved-memory";
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* ...
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* res0: res {
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* reg = <0x42000000 0x1000>;
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* label = "res0";
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* };
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* };
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*
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* n: node {
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* memory-region = <&res0>;
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* };
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*
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* Example usage:
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*
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* DT_RESERVED_MEM_GET_SIZE_BY_PHANDLE(DT_NODELABEL(n), memory_region) // (uint8_t *) 0x42000000
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*
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* @param node_id node identifier
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* @param ph phandle to reserved-memory region
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*
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* @return size of the reserved-memory region
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*/
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#define DT_RESERVED_MEM_GET_SIZE_BY_PHANDLE(node_id, ph) \
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DT_RESERVED_MEM_GET_SIZE(DT_PHANDLE(node_id, ph))
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/**
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* @}
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*/
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#ifdef __cplusplus
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}
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#endif
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#endif /* ZEPHYR_INCLUDE_DEVICETREE_MEMORY_H_ */

‎include/linker/devicetree_reserved.h‎

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/*
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* Copyright (c) 2021, Carlo Caione <[email protected]>
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Generate memory regions and sections from reserved-memory nodes.
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*/
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#include <devicetree.h>
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/* Reserved memory node */
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#define _NODE_RESERVED DT_INST(0, reserved_memory)
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/* Unquoted region label */
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#define _DT_LABEL_TOKEN(res) DT_STRING_TOKEN(res, label)
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/* _start and _end section symbols */
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#define _DT_RESERVED_PREFIX(res) UTIL_CAT(__, _DT_LABEL_TOKEN(res))
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#define _DT_RESERVED_START(res) UTIL_CAT(_DT_RESERVED_PREFIX(res), _start)
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#define _DT_RESERVED_END(res) UTIL_CAT(_DT_RESERVED_PREFIX(res), _end)
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/* Declare a reserved memory region */
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#define _RESERVED_REGION_DECLARE(res) DT_STRING_TOKEN(res, label) (rw) : \
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ORIGIN = DT_REG_ADDR(res), \
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LENGTH = DT_REG_SIZE(res)
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/* Declare a reserved memory section */
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#define _RESERVED_SECTION_DECLARE(res) SECTION_DATA_PROLOGUE(_DT_LABEL_TOKEN(res), ,) \
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{ \
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_DT_RESERVED_START(res) = .; \
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KEEP(*(._DT_LABEL_TOKEN(res))) \
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KEEP(*(._DT_LABEL_TOKEN(res).*)) \
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_DT_RESERVED_END(res) = \
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_DT_RESERVED_START(res) + DT_REG_SIZE(res); \
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} GROUP_LINK_IN(_DT_LABEL_TOKEN(res))
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/* Declare reserved memory linker symbols */
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#define _RESERVED_SYMBOL_DECLARE(res) extern char _DT_RESERVED_START(res)[]; \
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extern char _DT_RESERVED_END(res)[];
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/* Apply a macro to a reserved memory region */
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#define _RESERVED_REGION_APPLY(f) \
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COND_CODE_1(IS_ENABLED(UTIL_CAT(_NODE_RESERVED, _EXISTS)), \
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(DT_FOREACH_CHILD(_NODE_RESERVED, f)), ())
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/**
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* @brief Generate region definitions for all the reserved memory regions
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*/
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#define DT_RESERVED_MEM_REGIONS() _RESERVED_REGION_APPLY(_RESERVED_REGION_DECLARE)
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/**
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* @brief Generate section definitions for all the reserved memory regions
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*/
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#define DT_RESERVED_MEM_SECTIONS() _RESERVED_REGION_APPLY(_RESERVED_SECTION_DECLARE)
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/**
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* @brief Generate linker script symbols for all the reserved memory regions
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*/
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#define DT_RESERVED_MEM_SYMBOLS() _RESERVED_REGION_APPLY(_RESERVED_SYMBOL_DECLARE)

‎include/linker/linker-defs.h‎

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#ifdef ZTEST_UNITTEST
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#define DT_NODE_HAS_STATUS(node, status) 0
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#else
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#include <linker/devicetree_reserved.h>
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#include <devicetree.h>
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#endif
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extern char _vector_start[];
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extern char _vector_end[];
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#if DT_NODE_HAS_STATUS(_NODE_RESERVED, okay)
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DT_RESERVED_MEM_SYMBOLS()
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#endif
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#ifdef CONFIG_SW_VECTOR_RELAY
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extern char __vector_relay_table[];
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#endif

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