esp-idf/components/esp_hw_support/include/soc/esp32/spiram.h

/*
 * SPDX-FileCopyrightText: 2015-2021 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: Apache-2.0
 */


#ifndef __ESP_SPIRAM_H
#define __ESP_SPIRAM_H

#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
#include "esp_err.h"

#ifdef __cplusplus
extern "C" {
#endif

//TODO: IDF-4382, unify `target/spiram.h`, update migration guide as well

/**
 * @brief Initialize spiram interface/hardware. Normally called from cpu_start.c.
 *
 * @return ESP_OK on success
 */
esp_err_t esp_spiram_init(void);

/**
 * @brief Configure Cache/MMU for access to external SPI RAM.
 *
 * Normally this function is called from cpu_start, if CONFIG_SPIRAM_BOOT_INIT
 * option is enabled. Applications which need to enable SPI RAM at run time
 * can disable CONFIG_SPIRAM_BOOT_INIT, and call this function later.
 *
 * @attention this function must be called with flash cache disabled.
 */
void esp_spiram_init_cache(void);


/**
 * @brief Memory test for SPI RAM. Should be called after SPI RAM is initialized and
 * (in case of a dual-core system) the app CPU is online. This test overwrites the
 * memory with crap, so do not call after e.g. the heap allocator has stored important
 * stuff in SPI RAM.
 *
 * @return true on success, false on failed memory test
 */
bool esp_spiram_test(void);


/**
 * @brief Add the initialized SPI RAM to the heap allocator.
 */
esp_err_t esp_spiram_add_to_heapalloc(void);

/**
 * @brief Force a writeback of the data in the SPI RAM cache. This is to be called whenever
 * cache is disabled, because disabling cache on the ESP32 discards the data in the SPI
 * RAM cache.
 *
 * This is meant for use from within the SPI flash code.
 */
void esp_spiram_writeback_cache(void);

/**
 * @brief get psram CS IO
 *
 * This interface should be called after PSRAM is enabled, otherwise it will
 * return an invalid value -1/0xff.
 *
 * @return psram CS IO or -1/0xff if psram not enabled
 */
uint8_t esp_spiram_get_cs_io(void);


/**
 * @brief Reserve a pool of internal memory for specific DMA/internal allocations
 *
 * @param size Size of reserved pool in bytes
 *
 * @return
 *          - ESP_OK on success
 *          - ESP_ERR_NO_MEM when no memory available for pool
 */
esp_err_t esp_spiram_reserve_dma_pool(size_t size);


/**
 * @brief If SPI RAM(PSRAM) has been initialized
 *
 * @return
 *          - true SPI RAM has been initialized successfully
 *          - false SPI RAM hasn't been initialized or initialized failed
 */
bool esp_spiram_is_initialized(void);

#ifdef __cplusplus
}
#endif

#endif //  __ESP_SPIRAM_H