// Copyright 2015-2016 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.

#ifndef ESP_SPI_FLASH_H
#define ESP_SPI_FLASH_H

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

#ifdef __cplusplus
extern "C" {
#endif

#define ESP_ERR_FLASH_BASE       0x10010
#define ESP_ERR_FLASH_OP_FAIL    (ESP_ERR_FLASH_BASE + 1)
#define ESP_ERR_FLASH_OP_TIMEOUT (ESP_ERR_FLASH_BASE + 2)

#define SPI_FLASH_SEC_SIZE  4096    /**< SPI Flash sector size */

#define SPI_FLASH_MMU_PAGE_SIZE 0x10000 /**< Flash cache MMU mapping page size */

/**
 * @brief  Initialize SPI flash access driver
 *
 *  This function must be called exactly once, before any other 
 *  spi_flash_* functions are called.
 *  Currently this function is called from startup code. There is
 *  no need to call it from application code.
 *
 */
void spi_flash_init();

/**
 * @brief  Get flash chip size, as set in binary image header
 *
 * @note This value does not necessarily match real flash size.
 *
 * @return size of flash chip, in bytes
 */
size_t spi_flash_get_chip_size();

/**
 * @brief  Erase the Flash sector.
 *
 * @param  sector  Sector number, the count starts at sector 0, 4KB per sector.
 *
 * @return esp_err_t
 */
esp_err_t spi_flash_erase_sector(size_t sector);

/**
 * @brief  Erase a range of flash sectors
 *
 * @param  start_address  Address where erase operation has to start.
 *                                  Must be 4kB-aligned
 * @param  size  Size of erased range, in bytes. Must be divisible by 4kB.
 *
 * @return esp_err_t
 */
esp_err_t spi_flash_erase_range(size_t start_address, size_t size);


/**
 * @brief  Write data to Flash.
 *
 * @note If source address is in DROM, this function will return
 *       ESP_ERR_INVALID_ARG.
 *
 * @param  dest_addr destination address in Flash. Must be a multiple of 4 bytes.
 * @param  src       pointer to the source buffer.
 * @param  size      length of data, in bytes. Must be a multiple of 4 bytes.
 *
 * @return esp_err_t
 */
esp_err_t spi_flash_write(size_t dest_addr, const void *src, size_t size);


/**
 * @brief  Write data encrypted to Flash.
 *
 * @note Flash encryption must be enabled for this function to work.
 *
 * @note Flash encryption must be enabled when calling this function.
 * If flash encryption is disabled, the function returns
 * ESP_ERR_INVALID_STATE.  Use esp_flash_encryption_enabled()
 * function to determine if flash encryption is enabled.
 *
 * @note Both dest_addr and size must be multiples of 16 bytes. For
 * absolute best performance, both dest_addr and size arguments should
 * be multiples of 32 bytes.
 *
 * @param  dest_addr destination address in Flash. Must be a multiple of 16 bytes.
 * @param  src       pointer to the source buffer.
 * @param  size      length of data, in bytes. Must be a multiple of 16 bytes.
 *
 * @return esp_err_t
 */
esp_err_t spi_flash_write_encrypted(size_t dest_addr, const void *src, size_t size);

/**
 * @brief  Read data from Flash.
 *
 * @param  src_addr source address of the data in Flash.
 * @param  dest     pointer to the destination buffer
 * @param  size     length of data
 *
 * @return esp_err_t
 */
esp_err_t spi_flash_read(size_t src_addr, void *dest, size_t size);


/**
 * @brief  Read data from Encrypted Flash.
 *
 * If flash encryption is enabled, this function will transparently decrypt data as it is read.
 * If flash encryption is not enabled, this function behaves the same as spi_flash_read().
 *
 * See esp_flash_encryption_enabled() for a function to check if flash encryption is enabled.
 *
 * @param  src   source address of the data in Flash.
 * @param  dest  pointer to the destination buffer
 * @param  size  length of data
 *
 * @return esp_err_t
 */
esp_err_t spi_flash_read_encrypted(size_t src, void *dest, size_t size);

/**
 * @brief Enumeration which specifies memory space requested in an mmap call
 */
typedef enum {
    SPI_FLASH_MMAP_DATA,    /**< map to data memory (Vaddr0), allows byte-aligned access, 4 MB total */
    SPI_FLASH_MMAP_INST,    /**< map to instruction memory (Vaddr1-3), allows only 4-byte-aligned access, 11 MB total */
} spi_flash_mmap_memory_t;

/**
 * @brief Opaque handle for memory region obtained from spi_flash_mmap.
 */
typedef uint32_t spi_flash_mmap_handle_t;

/**
 * @brief Map region of flash memory into data or instruction address space
 *
 * This function allocates sufficient number of 64k MMU pages and configures
 * them to map request region of flash memory into data address space or into
 * instruction address space. It may reuse MMU pages which already provide
 * required mapping. As with any allocator, there is possibility of fragmentation
 * of address space if mmap/munmap are heavily used. To troubleshoot issues with
 * page allocation, use spi_flash_mmap_dump function.
 *
 * @param src_addr  Physical address in flash where requested region starts.
 *                  This address *must* be aligned to 64kB boundary
 *                  (SPI_FLASH_MMU_PAGE_SIZE).
 * @param size  Size of region which has to be mapped. This size will be rounded
 *              up to a 64k boundary.
 * @param memory  Memory space where the region should be mapped
 * @param out_ptr  Output, pointer to the mapped memory region
 * @param out_handle  Output, handle which should be used for spi_flash_munmap call
 *
 * @return  ESP_OK on success, ESP_ERR_NO_MEM if pages can not be allocated
 */
esp_err_t spi_flash_mmap(size_t src_addr, size_t size, spi_flash_mmap_memory_t memory,
                         const void** out_ptr, spi_flash_mmap_handle_t* out_handle);

/**
 * @brief Map sequences of pages of flash memory into data or instruction address space
 *
 * This function allocates sufficient number of 64k MMU pages and configures
 * them to map the indicated pages of flash memory contiguously into data address 
 * space or into instruction address space. In this respect, it works in a similar
 * way as spi_flash_mmap but it allows mapping a (maybe non-contiguous) set of pages
 * into a contiguous region of memory.
 *
 * @param pages An array of numbers indicating the 64K pages in flash to be mapped
 *              contiguously into memory. These indicate the indexes of the 64K pages,
 *              not the byte-size addresses as used in other functions.
 * @param pagecount  Size of the pages array
 * @param memory  Memory space where the region should be mapped
 * @param out_ptr  Output, pointer to the mapped memory region
 * @param out_handle  Output, handle which should be used for spi_flash_munmap call
 *
 * @return  ESP_OK on success, ESP_ERR_NO_MEM if pages can not be allocated
 */
esp_err_t spi_flash_mmap_pages(int *pages, size_t pagecount, spi_flash_mmap_memory_t memory,
                         const void** out_ptr, spi_flash_mmap_handle_t* out_handle);


/**
 * @brief Release region previously obtained using spi_flash_mmap
 *
 * @note Calling this function will not necessarily unmap memory region.
 *       Region will only be unmapped when there are no other handles which
 *       reference this region. In case of partially overlapping regions
 *       it is possible that memory will be unmapped partially.
 *
 * @param handle  Handle obtained from spi_flash_mmap
 */
void spi_flash_munmap(spi_flash_mmap_handle_t handle);

/**
 * @brief Display information about mapped regions
 *
 * This function lists handles obtained using spi_flash_mmap, along with range
 * of pages allocated to each handle. It also lists all non-zero entries of
 * MMU table and corresponding reference counts.
 */
void spi_flash_mmap_dump();


#define SPI_FLASH_CACHE2PHYS_FAIL UINT32_MAX /*<! Result from spi_flash_cache2phys() if flash cache address is invalid */

/**
 * @brief Given a memory address where flash is mapped, return the corresponding physical flash offset.
 *
 * Cache address does not have have been assigned via spi_flash_mmap(), any address in flash map space can be looked up.
 *
 * @param cached Pointer to flashed cached memory.
 *
 * @return
 * - SPI_FLASH_CACHE2PHYS_FAIL If cache address is outside flash cache region, or the address is not mapped.
 * - Otherwise, returns physical offset in flash
 */
size_t spi_flash_cache2phys(const void *cached);

/** @brief Given a physical offset in flash, return the address where it is mapped in the memory space.
 *
 * Physical address does not have to have been assigned via spi_flash_mmap(), any address in flash can be looked up.
 *
 * @note Only the first matching cache address is returned. If MMU flash cache table is configured so multiple entries
 * point to the same physical address, there may be more than one cache address corresponding to that physical
 * address. It is also possible for a single physical address to be mapped to both the IROM and DROM regions.
 *
 * @note This function doesn't impose any alignment constraints, but if memory argument is SPI_FLASH_MMAP_INST and
 * phys_offs is not 4-byte aligned, then reading from the returned pointer will result in a crash.
 *
 * @param phys_offs Physical offset in flash memory to look up.
 * @param memory Memory type to look up a flash cache address mapping for (IROM or DROM)
 *
 * @return
 * - NULL if the physical address is invalid or not mapped to flash cache of the specified memory type.
 * - Cached memory address (in IROM or DROM space) corresponding to phys_offs.
 */
const void *spi_flash_phys2cache(size_t phys_offs, spi_flash_mmap_memory_t memory);

/** @brief Check at runtime if flash cache is enabled on both CPUs
 *
 * @return true if both CPUs have flash cache enabled, false otherwise.
 */
bool spi_flash_cache_enabled();

/**
 * @brief SPI flash critical section enter function.
 */
typedef void (*spi_flash_guard_start_func_t)(void);
/**
 * @brief SPI flash critical section exit function.
 */
typedef void (*spi_flash_guard_end_func_t)(void);
/**
 * @brief SPI flash operation lock function.
 */
typedef void (*spi_flash_op_lock_func_t)(void);
/**
 * @brief SPI flash operation unlock function.
 */
typedef void (*spi_flash_op_unlock_func_t)(void);

/**
 * Structure holding SPI flash access critical sections management functions.
 *
 * Flash API uses two types of flash access management functions:
 * 1) Functions which prepare/restore flash cache and interrupts before calling
 *    appropriate ROM functions (SPIWrite, SPIRead and SPIEraseBlock):
 *   - 'start' function should disables flash cache and non-IRAM interrupts and
 *      is invoked before the call to one of ROM function above.
 *   - 'end' function should restore state of flash cache and non-IRAM interrupts and
 *      is invoked after the call to one of ROM function above.
 *    These two functions are not recursive.
 * 2) Functions which synchronizes access to internal data used by flash API.
 *    This functions are mostly intended to synchronize access to flash API internal data
 *    in multithreaded environment and use OS primitives:
 *   - 'op_lock' locks access to flash API internal data.
 *   - 'op_unlock' unlocks access to flash API internal data.
 *   These two functions are recursive and can be used around the outside of multiple calls to
 *   'start' & 'end', in order to create atomic multi-part flash operations.
 *
 * Different versions of the guarding functions should be used depending on the context of
 * execution (with or without functional OS). In normal conditions when flash API is called
 * from task the functions use OS primitives. When there is no OS at all or when
 * it is not guaranteed that OS is functional (accessing flash from exception handler) these
 * functions cannot use OS primitives or even does not need them (multithreaded access is not possible).
 *
 * @note Structure and corresponding guard functions should not reside in flash.
 *       For example structure can be placed in DRAM and functions in IRAM sections.
 */
typedef struct {
    spi_flash_guard_start_func_t    start;      /**< critical section start function. */
    spi_flash_guard_end_func_t      end;        /**< critical section end function. */
    spi_flash_op_lock_func_t        op_lock;    /**< flash access API lock function.*/
    spi_flash_op_unlock_func_t      op_unlock;  /**< flash access API unlock function.*/
} spi_flash_guard_funcs_t;

/**
 * @brief  Sets guard functions to access flash.
 *
 * @note Pointed structure and corresponding guard functions should not reside in flash.
 *       For example structure can be placed in DRAM and functions in IRAM sections.
 *
 * @param funcs pointer to structure holding flash access guard functions.
 */
void spi_flash_guard_set(const spi_flash_guard_funcs_t* funcs);


/**
 * @brief Get the guard functions used for flash access
 *
 * @return The guard functions that were set via spi_flash_guard_set(). These functions
 * can be called if implementing custom low-level SPI flash operations.
 */
const spi_flash_guard_funcs_t *spi_flash_guard_get();

/**
 * @brief Default OS-aware flash access guard functions
 */
extern const spi_flash_guard_funcs_t g_flash_guard_default_ops;

/**
 * @brief Non-OS flash access guard functions
 *
 * @note This version of flash guard functions is to be used when no OS is present or from panic handler.
 *       It does not use any OS primitives and IPC and implies that only calling CPU is active.
 */
extern const spi_flash_guard_funcs_t g_flash_guard_no_os_ops;

#if CONFIG_SPI_FLASH_ENABLE_COUNTERS

/**
 * Structure holding statistics for one type of operation
 */
typedef struct {
    uint32_t count;     // number of times operation was executed
    uint32_t time;      // total time taken, in microseconds
    uint32_t bytes;     // total number of bytes
} spi_flash_counter_t;

typedef struct {
    spi_flash_counter_t read;
    spi_flash_counter_t write;
    spi_flash_counter_t erase;
} spi_flash_counters_t;

/**
 * @brief  Reset SPI flash operation counters
 */
void spi_flash_reset_counters();

/**
 * @brief  Print SPI flash operation counters
 */
void spi_flash_dump_counters();

/**
 * @brief  Return current SPI flash operation counters
 *
 * @return  pointer to the spi_flash_counters_t structure holding values
 *          of the operation counters
 */
const spi_flash_counters_t* spi_flash_get_counters();

#endif //CONFIG_SPI_FLASH_ENABLE_COUNTERS

#ifdef __cplusplus
}
#endif


#endif /* ESP_SPI_FLASH_H */

