kopia lustrzana https://github.com/espressif/esp-idf
206 wiersze
7.6 KiB
C
206 wiersze
7.6 KiB
C
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// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#pragma once
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#include "hal/sha_types.h"
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#include "esp_types.h"
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/** @brief Low-level support functions for the hardware SHA engine
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*
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* @note If you're looking for a SHA API to use, try mbedtls component
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* mbedtls/shaXX.h. That API supports hardware acceleration.
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*
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* The API in this header provides some building blocks for implementing a
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* full SHA API such as the one in mbedtls, and also a basic SHA function esp_sha().
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*
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* Some technical details about the hardware SHA engine:
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*
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* - SHA accelerator engine calculates one digest at a time, per SHA
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* algorithm type. It initialises and maintains the digest state
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* internally. It is possible to read out an in-progress SHA digest
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* state, but it is not possible to restore a SHA digest state
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* into the engine.
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*
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* - The memory block SHA_TEXT_BASE is shared between all SHA digest
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* engines, so all engines must be idle before this memory block is
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* modified.
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*
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*/
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#ifdef __cplusplus
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extern "C" {
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#endif
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/** @brief Calculate SHA1 or SHA2 sum of some data, using hardware SHA engine
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*
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* @note For more versatile SHA calculations, where data doesn't need
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* to be passed all at once, try the mbedTLS mbedtls/shaX.h APIs. The
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* hardware-accelerated mbedTLS implementation is also faster when
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* hashing large amounts of data.
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*
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* @note It is not necessary to lock any SHA hardware before calling
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* this function, thread safety is managed internally.
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*
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* @note If a TLS connection is open then this function may block
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* indefinitely waiting for a SHA engine to become available. Use the
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* mbedTLS SHA API to avoid this problem.
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*
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* @param sha_type SHA algorithm to use.
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*
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* @param input Input data buffer.
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*
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* @param ilen Length of input data in bytes.
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*
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* @param output Buffer for output SHA digest. Output is 20 bytes for
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* sha_type SHA1, 32 bytes for sha_type SHA2_256, 48 bytes for
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* sha_type SHA2_384, 64 bytes for sha_type SHA2_512.
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*/
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void esp_sha(esp_sha_type sha_type, const unsigned char *input, size_t ilen, unsigned char *output);
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/* @brief Begin to execute a single SHA block operation
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*
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* @note This is a piece of a SHA algorithm, rather than an entire SHA
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* algorithm.
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*
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* @note Call esp_sha_try_lock_engine() before calling this
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* function. Do not call esp_sha_lock_memory_block() beforehand, this
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* is done inside the function.
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*
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* @param sha_type SHA algorithm to use.
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*
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* @param data_block Pointer to block of data. Block size is
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* determined by algorithm (SHA1/SHA2_256 = 64 bytes,
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* SHA2_384/SHA2_512 = 128 bytes)
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*
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* @param is_first_block If this parameter is true, the SHA state will
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* be initialised (with the initial state of the given SHA algorithm)
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* before the block is calculated. If false, the existing state of the
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* SHA engine will be used.
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*
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* @return As a performance optimisation, this function returns before
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* the SHA block operation is complete. Both this function and
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* esp_sha_read_state() will automatically wait for any previous
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* operation to complete before they begin. If using the SHA registers
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* directly in another way, call esp_sha_wait_idle() after calling this
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* function but before accessing the SHA registers.
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*/
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void esp_sha_block(esp_sha_type sha_type, const void *data_block, bool is_first_block);
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/** @brief Read out the current state of the SHA digest loaded in the engine.
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*
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* @note This is a piece of a SHA algorithm, rather than an entire SHA algorithm.
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*
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* @note Call esp_sha_try_lock_engine() before calling this
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* function. Do not call esp_sha_lock_memory_block() beforehand, this
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* is done inside the function.
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*
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* If the SHA suffix padding block has been executed already, the
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* value that is read is the SHA digest (in big endian
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* format). Otherwise, the value that is read is an interim SHA state.
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*
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* @note If sha_type is SHA2_384, only 48 bytes of state will be read.
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* This is enough for the final SHA2_384 digest, but if you want the
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* interim SHA-384 state (to continue digesting) then pass SHA2_512 instead.
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*
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* @param sha_type SHA algorithm in use.
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*
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* @param state Pointer to a memory buffer to hold the SHA state. Size
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* is 20 bytes (SHA1), 32 bytes (SHA2_256), 48 bytes (SHA2_384) or 64 bytes (SHA2_512).
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*
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*/
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void esp_sha_read_digest_state(esp_sha_type sha_type, void *digest_state);
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/**
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* @brief Obtain exclusive access to a particular SHA engine
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*
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* @param sha_type Type of SHA engine to use.
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*
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* Blocks until engine is available. Note: Can block indefinitely
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* while a TLS connection is open, suggest using
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* esp_sha_try_lock_engine() and failing over to software SHA.
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*/
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void esp_sha_lock_engine(esp_sha_type sha_type);
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/**
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* @brief Try and obtain exclusive access to a particular SHA engine
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*
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* @param sha_type Type of SHA engine to use.
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*
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* @return Returns true if the SHA engine is locked for exclusive
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* use. Call esp_sha_unlock_sha_engine() when done. Returns false if
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* the SHA engine is already in use, caller should use software SHA
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* algorithm for this digest.
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*/
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bool esp_sha_try_lock_engine(esp_sha_type sha_type);
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/**
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* @brief Unlock an engine previously locked with esp_sha_lock_engine() or esp_sha_try_lock_engine()
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*
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* @param sha_type Type of engine to release.
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*/
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void esp_sha_unlock_engine(esp_sha_type sha_type);
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/**
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* @brief Acquire exclusive access to the SHA shared memory block at SHA_TEXT_BASE
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*
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* This memory block is shared across all the SHA algorithm types.
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*
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* Caller should have already locked a SHA engine before calling this function.
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*
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* Note that it is possible to obtain exclusive access to the memory block even
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* while it is in use by the SHA engine. Caller should use esp_sha_wait_idle()
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* to ensure the SHA engine is not reading from the memory block in hardware.
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*
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* @note This function enters a critical section. Do not block while holding this lock.
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*
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* @note You do not need to lock the memory block before calling esp_sha_block() or esp_sha_read_digest_state(), these functions handle memory block locking internally.
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*
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* Call esp_sha_unlock_memory_block() when done.
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*/
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void esp_sha_lock_memory_block(void);
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/**
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* @brief Release exclusive access to the SHA register memory block at SHA_TEXT_BASE
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*
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* Caller should have already locked a SHA engine before calling this function.
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*
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* This function releases the critical section entered by esp_sha_lock_memory_block().
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*
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* Call following esp_sha_lock_memory_block().
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*/
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void esp_sha_unlock_memory_block(void);
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/** @brief Wait for the SHA engine to finish any current operation
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*
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* @note This function does not ensure exclusive access to any SHA
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* engine. Caller should use esp_sha_try_lock_engine() and
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* esp_sha_lock_memory_block() as required.
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*
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* @note Functions declared in this header file wait for SHA engine
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* completion automatically, so you don't need to use this API for
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* these. However if accessing SHA registers directly, you will need
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* to call this before accessing SHA registers if using the
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* esp_sha_block() function.
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*
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* @note This function busy-waits, so wastes CPU resources.
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* Best to delay calling until you are about to need it.
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*
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*/
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void esp_sha_wait_idle(void);
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#ifdef __cplusplus
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}
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#endif
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