esp_flash.h

// Copyright 2015-2019 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#pragma once
#include "esp_err.h"
#include <stdint.h>
#include <stdbool.h>

#include "hal/spi_flash_types.h"

#ifdef __cplusplus
extern "C" {
#endif

struct spi_flash_chip_t;
typedef struct spi_flash_chip_t spi_flash_chip_t;

typedef struct esp_flash_t esp_flash_t;

/** @brief Structure for describing a region of flash */
typedef struct {
    uint32_t offset;    ///< Start address of this region
    uint32_t size;      ///< Size of the region
} esp_flash_region_t;

/** OS-level integration hooks for accessing flash chips inside a running OS */
typedef struct {
    /**
     * Called before commencing any flash operation. Does not need to be
     * recursive (ie is called at most once for each call to 'end').
     */
    esp_err_t (*start)(void *arg);

    /** Called after completing any flash operation. */
    esp_err_t (*end)(void *arg);

    /** Called before any erase/write operations to check whether the region is limited by the OS */
    esp_err_t (*region_protected)(void* arg, size_t start_addr, size_t size);

    /** Delay for at least 'us' microseconds. Called in between 'start' and 'end'. */
    esp_err_t (*delay_us)(void *arg, unsigned us);

    /** Yield to other tasks. Called during erase operations. */
    esp_err_t (*yield)(void *arg);
} esp_flash_os_functions_t;

/** @brief Structure to describe a SPI flash chip connected to the system.

    Structure must be initialized before use (passed to esp_flash_init()).
*/
struct esp_flash_t {
    spi_flash_host_driver_t *host;      ///< Pointer to hardware-specific "host_driver" structure. Must be initialized before used.
    const spi_flash_chip_t *chip_drv;   ///< Pointer to chip-model-specific "adapter" structure. If NULL, will be detected during initialisation.

    const esp_flash_os_functions_t *os_func;    ///< Pointer to os-specific hook structure. Call ``esp_flash_init_os_functions()`` to setup this field, after the host is properly initialized.
    void *os_func_data;                         ///< Pointer to argument for os-specific hooks. Left NULL and will be initialized with ``os_func``.

    esp_flash_io_mode_t read_mode; ///< Configured SPI flash read mode. Set before ``esp_flash_init`` is called.
    uint32_t size;                   ///< Size of SPI flash in bytes. If 0, size will be detected during initialisation.
    uint32_t chip_id;               ///< Detected chip id.
};


/** @brief Initialise SPI flash chip interface.
 *
 * This function must be called before any other API functions are called for this chip.
 *
 * @note Only the ``host`` and ``read_mode`` fields of the chip structure must
 *       be initialised before this function is called. Other fields may be
 *       auto-detected if left set to zero or NULL.
 *
 * @note If the chip->drv pointer is NULL, chip chip_drv will be auto-detected
 *       based on its manufacturer & product IDs. See
 *       ``esp_flash_registered_flash_drivers`` pointer for details of this process.
 *
 * @param chip Pointer to SPI flash chip to use. If NULL, esp_flash_default_chip is substituted.
 * @return ESP_OK on success, or a flash error code if initialisation fails.
 */
esp_err_t esp_flash_init(esp_flash_t *chip);

/**
 * Check if appropriate chip driver is set.
 *
 * @param chip Pointer to SPI flash chip to use. If NULL, esp_flash_default_chip is substituted.
 *
 * @return true if set, otherwise false.
 */
bool esp_flash_chip_driver_initialized(const esp_flash_t *chip);

/** @brief Read flash ID via the common "RDID" SPI flash command.
 *
 * @param chip Pointer to identify flash chip. Must have been successfully initialised via esp_flash_init()
 * @param[out] out_id Pointer to receive ID value.
 *
 * ID is a 24-bit value. Lower 16 bits of 'id' are the chip ID, upper 8 bits are the manufacturer ID.
 *
 * @return ESP_OK on success, or a flash error code if operation failed.
 */
esp_err_t esp_flash_read_id(esp_flash_t *chip, uint32_t *out_id);

/** @brief Detect flash size based on flash ID.
 *
 * @param chip Pointer to identify flash chip. Must have been successfully initialised via esp_flash_init()
 * @param[out] out_size Detected size in bytes.
 *
 * @note Most flash chips use a common format for flash ID, where the lower 4 bits specify the size as a power of 2. If
 * the manufacturer doesn't follow this convention, the size may be incorrectly detected.
 *
 * @return ESP_OK on success, or a flash error code if operation failed.
 */
esp_err_t esp_flash_get_size(esp_flash_t *chip, uint32_t *out_size);

/** @brief Erase flash chip contents
 *
 * @param chip Pointer to identify flash chip. Must have been successfully initialised via esp_flash_init()
 *
 *
 * @return ESP_OK on success, or a flash error code if operation failed.
 */
esp_err_t esp_flash_erase_chip(esp_flash_t *chip);

/** @brief Erase a region of the flash chip
 *
 * @param chip Pointer to identify flash chip. Must have been successfully initialised via esp_flash_init()
 * @param start Address to start erasing flash. Must be sector aligned.
 * @param len Length of region to erase. Must also be sector aligned.
 *
 * Sector size is specifyed in chip->drv->sector_size field (typically 4096 bytes.) ESP_ERR_INVALID_ARG will be
 * returned if the start & length are not a multiple of this size.
 *
 * Erase is performed using block (multi-sector) erases where possible (block size is specified in
 * chip->drv->block_erase_size field, typically 65536 bytes). Remaining sectors are erased using individual sector erase
 * commands.
 *
 * @return ESP_OK on success, or a flash error code if operation failed.
 */
esp_err_t esp_flash_erase_region(esp_flash_t *chip, uint32_t start, uint32_t len);

/** @brief Read if the entire chip is write protected
 *
 * @param chip Pointer to identify flash chip. Must have been successfully initialised via esp_flash_init()
 * @param[out] write_protected Pointer to boolean, set to the value of the write protect flag.
 *
 * @note A correct result for this flag depends on the SPI flash chip model and chip_drv in use (via the 'chip->drv'
 * field).
 *
 * @return ESP_OK on success, or a flash error code if operation failed.
 */
esp_err_t esp_flash_get_chip_write_protect(esp_flash_t *chip, bool *write_protected);

/** @brief Set write protection for the SPI flash chip
 *
 * @param chip Pointer to identify flash chip. Must have been successfully initialised via esp_flash_init()
 * @param write_protect Boolean value for the write protect flag
 *
 * @note Correct behaviour of this function depends on the SPI flash chip model and chip_drv in use (via the 'chip->drv'
 * field).
 *
 * Some SPI flash chips may require a power cycle before write protect status can be cleared. Otherwise,
 * write protection can be removed via a follow-up call to this function.
 *
 * @return ESP_OK on success, or a flash error code if operation failed.
 */
esp_err_t esp_flash_set_chip_write_protect(esp_flash_t *chip, bool write_protect);


/** @brief Read the list of individually protectable regions of this SPI flash chip.
 *
 * @param chip Pointer to identify flash chip. Must have been successfully initialised via esp_flash_init()
 * @param[out] out_regions Pointer to receive a pointer to the array of protectable regions of the chip.
 * @param[out] out_num_regions Pointer to an integer receiving the count of protectable regions in the array returned in 'regions'.
 *
 * @note Correct behaviour of this function depends on the SPI flash chip model and chip_drv in use (via the 'chip->drv'
 * field).
 *
 * @return ESP_OK on success, or a flash error code if operation failed.
 */
esp_err_t esp_flash_get_protectable_regions(const esp_flash_t *chip, const esp_flash_region_t **out_regions, uint32_t *out_num_regions);


/** @brief Detect if a region of the SPI flash chip is protected
 *
 * @param chip Pointer to identify flash chip. Must have been successfully initialised via esp_flash_init()
 * @param region Pointer to a struct describing a protected region. This must match one of the regions returned from esp_flash_get_protectable_regions(...).
 * @param[out] out_protected Pointer to a flag which is set based on the protected status for this region.
 *
 * @note It is possible for this result to be false and write operations to still fail, if protection is enabled for the entire chip.
 *
 * @note Correct behaviour of this function depends on the SPI flash chip model and chip_drv in use (via the 'chip->drv'
 * field).
 *
 * @return ESP_OK on success, or a flash error code if operation failed.
 */
esp_err_t esp_flash_get_protected_region(esp_flash_t *chip, const esp_flash_region_t *region, bool *out_protected);

/** @brief Update the protected status for a region of the SPI flash chip
 *
 * @param chip Pointer to identify flash chip. Must have been successfully initialised via esp_flash_init()
 * @param region Pointer to a struct describing a protected region. This must match one of the regions returned from esp_flash_get_protectable_regions(...).
 * @param protect Write protection flag to set.
 *
 * @note It is possible for the region protection flag to be cleared and write operations to still fail, if protection is enabled for the entire chip.
 *
 * @note Correct behaviour of this function depends on the SPI flash chip model and chip_drv in use (via the 'chip->drv'
 * field).
 *
 * @return ESP_OK on success, or a flash error code if operation failed.
 */
esp_err_t esp_flash_set_protected_region(esp_flash_t *chip, const esp_flash_region_t *region, bool protect);

/** @brief Read data from the SPI flash chip
 *
 * @param chip Pointer to identify flash chip. Must have been successfully initialised via esp_flash_init()
 * @param buffer Pointer to a buffer where the data will be read. To get better performance, this should be in the DRAM and word aligned.
 * @param address Address on flash to read from. Must be less than chip->size field.
 * @param length Length (in bytes) of data to read.
 *
 * There are no alignment constraints on buffer, address or length.
 *
 * @note If on-chip flash encryption is used, this function returns raw (ie encrypted) data. Use the flash cache
 * to transparently decrypt data.
 *
 * @return
 *      - ESP_OK: success
 *      - ESP_ERR_NO_MEM: Buffer is in external PSRAM which cannot be concurrently accessed, and a temporary internal buffer could not be allocated.
 *      - or a flash error code if operation failed.
 */
esp_err_t esp_flash_read(esp_flash_t *chip, void *buffer, uint32_t address, uint32_t length);

/** @brief Write data to the SPI flash chip
 *
 * @param chip Pointer to identify flash chip. Must have been successfully initialised via esp_flash_init()
 * @param address Address on flash to write to. Must be previously erased (SPI NOR flash can only write bits 1->0).
 * @param buffer Pointer to a buffer with the data to write. To get better performance, this should be in the DRAM and word aligned.
 * @param length Length (in bytes) of data to write.
 *
 * There are no alignment constraints on buffer, address or length.
 *
 * @return ESP_OK on success, or a flash error code if operation failed.
 */
esp_err_t esp_flash_write(esp_flash_t *chip, const void *buffer, uint32_t address, uint32_t length);

/** @brief Encrypted and write data to the SPI flash chip using on-chip hardware flash encryption
 *
 * @param chip Pointer to identify flash chip. Must be NULL (the main flash chip). For other chips, encrypted write is not supported.
 * @param address Address on flash to write to. 16 byte aligned. Must be previously erased (SPI NOR flash can only write bits 1->0).
 * @param buffer Pointer to a buffer with the data to write.
 * @param length Length (in bytes) of data to write. 16 byte aligned.
 *
 * @note Both address & length must be 16 byte aligned, as this is the encryption block size
 *
 * @return
 *  - ESP_OK: on success
 *  - ESP_ERR_NOT_SUPPORTED: encrypted write not supported for this chip.
 *  - ESP_ERR_INVALID_ARG: Either the address, buffer or length is invalid.
 *  - or other flash error code from spi_flash_write_encrypted().
 */
esp_err_t esp_flash_write_encrypted(esp_flash_t *chip, uint32_t address, const void *buffer, uint32_t length);

/** @brief Read and decrypt data from the SPI flash chip using on-chip hardware flash encryption
 *
 * @param chip Pointer to identify flash chip. Must be NULL (the main flash chip). For other chips, encrypted read is not supported.
 * @param address Address on flash to read from.
 * @param out_buffer Pointer to a buffer for the data to read to.
 * @param length Length (in bytes) of data to read.
 *
 * @return
 *  - ESP_OK: on success
 *  - ESP_ERR_NOT_SUPPORTED: encrypted read not supported for this chip.
 *  - or other flash error code from spi_flash_read_encrypted().
 */
esp_err_t esp_flash_read_encrypted(esp_flash_t *chip, uint32_t address, void *out_buffer, uint32_t length);

/** @brief Pointer to the "default" SPI flash chip, ie the main chip attached to the MCU.

   This chip is used if the 'chip' argument pass to esp_flash_xxx API functions is ever NULL.
*/
extern esp_flash_t *esp_flash_default_chip;


/*******************************************************************************
 * Utility Functions
 ******************************************************************************/

/**
 * @brief Returns true if chip is configured for Quad I/O or Quad Fast Read.
 *
 * @param chip Pointer to SPI flash chip to use. If NULL, esp_flash_default_chip is substituted.
 *
 * @return true if flash works in quad mode, otherwise false
 */
static inline bool esp_flash_is_quad_mode(const esp_flash_t *chip)
{
    return (chip->read_mode == SPI_FLASH_QIO) || (chip->read_mode == SPI_FLASH_QOUT);
}

#ifdef __cplusplus
}
#endif