SDSPI.h

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/*
 * Copyright (c) 2015-2016, Texas Instruments Incorporated
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/*!*****************************************************************************
 *  @file       SDSPI.h
 *
 *  @brief      SDSPI driver interface
 *
 *  The SDSPI header file should be included in an application as follows:
 *  @code
 *  #include <ti/drivers/SDSPI.h>
 *  @endcode
 *
 *  # Overview #
 *  The SDSPI FatFs driver is used to communicate with SD (Secure Digital)
 *  cards via SPI (Serial Peripheral Interface).
 *
 *  The SDSPI driver is a FatFs driver module for the FatFs middleware
 *  module. With the exception of the standard driver APIs -
 *  SDSPI_open(), SDSPI_close(), and SDSPI_init() - the SDSPI driver
 *  is exclusively used by FatFs module to handle the low-level hardware
 *  communications.
 *
 *  The SDSPI driver only supports one SSI (SPI) peripheral at a given time.
 *  It does not utilize interrupts.
 *
 *  The SDSPI driver is polling based for performance reasons and due to the
 *  relatively high SPI bus bit rate. This means it does not utilize the
 *  SPI's peripheral interrupts, and it consumes the entire CPU time when
 *  communicating with the SPI bus. Data transfers to or from the SD card
 *  are typically 512 bytes, which could take a significant amount of time
 *  to complete. During this time, only higher priority Tasks, Swis, and
 *  Hwis can preempt Tasks making calls that use the FatFs.
 *
 *  # Usage #
 *  Before any FatFs or C I/O APIs can be used, the application needs to
 *  open the SDSPI driver. The SDSPI_open() function ensures that the SDSPI
 *  disk functions get registered with the FatFs module that subsequently
 *  mounts the FatFs volume to that particular drive.
 *
 *  @code
 *    SDSPI_Handle sdspiHandle;
 *    SDSPI_Params sdspiParams;
 *    UInt peripheralNum = 0;
 *    UInt FatFsDriveNum = 0;
 *
 *    SDSPI_Params_init(&sdspiParams);
 *
 *    sdspiHandle = SDSPI_open(peripheralNum, FatFsDriveNum, &sdspiParams);
 *    if (sdspiHandle == NULL) {
 *        System_abort("Error opening SDSPI\n");
 *    }
 *  @endcode
 *
 *  Similarly, the SDSPI_close() function unmounts the FatFs volume and
 *  unregisters SDSPI disk functions.
 *
 *  @code
 *    SDSPI_close(sdspiHandle);
 *  @endcode
 *
 *  Note that it is up to the application to ensure the no FatFs or C I/O
 *  APIs are called before the SDSPI driver has been opened or after the
 *  SDSPI driver has been closed.
 *
 *  ### SDSPI Driver Configuration #
 *  The SDSPI driver requires the application to initialize board-specific
 *  portions of the SDSPI and provide the SDSPI driver with the SDSPI_config
 *  structure.
 *
 *  #### Board-Specific Configuration #
 *
 *  The SDSPI_init() initializes the SDSPI driver snd any board-specific
 *  SDSPI peripheral settings.
 *
 *  #### SDSPI_config Structure #
 *
 *  The <*board*>.c file declares the SDSPI_config structure. This
 *  structure must be provided to the SDSPI driver. It must be initialized
 *  before the SDSPI_init() function is called and cannot be changed
 *  afterwards.
 *
 *  The SDSPI driver interface defines a configuration data structure:
 *
 *  @code
 *    typedef struct SDSPI_Config_ {
 *        SDSPI_FxnTable const *fxnTablePtr;
 *        void                 *object;
 *        void           const *hwAttrs;
 *    } SDSPI_Config;
 *  @endcode
 *
 *  # Operation #
 *
 *  The SDSPI driver is a driver designed to hook into FatFs. It implements a
 *  set of functions that FatFs needs to call to perform basic block data
 *  transfers.
 *
 *  A SDSPI driver peripheral implementation doesn't require RTOS protection
 *  primitives due to the resource protection provided with FatFs. The only
 *  functions that can be called by the application are the standard driver
 *  framework functions (_open, _close, etc...).
 *
 *  Once the driver has been opened, the application may used the FatFs APIs or
 *  the standard C runtime file I/O calls (fopen, fclose, etc...). Once the
 *  driver has been closed, ensure the application does NOT make any file I/O
 *  calls.
 *
 *  ### Opening the SDSPI driver #
 *
 *  @code
 *    SDSPI_Handle handle;
 *    SDSPI_Params params;
 *
 *    SDSPI_Params_init(&params);
 *    params.bitRate = someNewBitRate;
 *    handle = SDSPI_open(someSDSPI_configIndexValue, &params);
 *    if (!handle) {
 *        System_printf("SDSPI did not open");
 *    }
 *  @endcode
 *
 *  # Implementation #
 *
 *  The SDSPI driver interface module is joined (at link time) to an
 *  array of SDSPI_Config data structures named *SDSPI_config*.
 *  SDSPI_config is implemented in the application with each entry being an
 *  instance of a SDSPI peripheral. Each entry in *SDSPI_config* contains a:
 *  - (SDSPI_FxnTable *) to a set of functions that implement a SDSPI peripheral
 *  - (void *) data object that is associated with the SDSPI_FxnTable
 *  - (void *) hardware attributes that are associated with the SDSPI_FxnTable
 *
 *  The SDSPI APIs are redirected to the device specific implementations
 *  using the SDSPI_FxnTable pointer of the SDSPI_config entry.
 *  In order to use device specific functions of the SDSPI driver directly,
 *  link in the correct driver library for your device and include the
 *  device specific SDSPI driver header file (which in turn includes SDSPI.h).
 *  For example, for the MSP432 family of devices, you would include the
 *  following header file:
 *  @code
 *    #include <ti/drivers/sdspi/SDSPIMSP432.h>
 *  @endcode
 *
 *******************************************************************************
 */

#ifndef ti_drivers_SDSPI__include
#define ti_drivers_SDSPI__include

#ifdef __cplusplus
extern "C" {
#endif

#include <stdint.h>

#define SDSPI_CMD_RESERVED           (32)

#define SDSPI_STATUS_RESERVED       (-32)

#define SDSPI_STATUS_SUCCESS        (0)

#define SDSPI_STATUS_ERROR         (-1)

#define SDSPI_STATUS_UNDEFINEDCMD  (-2)

/* Add SDSPI_CMD_<commands> here */

typedef struct SDSPI_Config_ *SDSPI_Handle;


typedef struct SDSPI_Params_ {
    uint32_t  bitRate; 
    void     *custom;  
} SDSPI_Params;

typedef void          (*SDSPI_InitFxn)     (SDSPI_Handle handle);

typedef SDSPI_Handle  (*SDSPI_OpenFxn)   (SDSPI_Handle handle,
                                          uint_least8_t drv,
                                          SDSPI_Params *params);

typedef void          (*SDSPI_CloseFxn)    (SDSPI_Handle handle);

typedef int_fast16_t  (*SDSPI_ControlFxn)  (SDSPI_Handle handle,
                                            uint_fast16_t cmd,
                                            void *arg);

typedef struct SDSPI_FxnTable_ {
    SDSPI_InitFxn initFxn;

    SDSPI_OpenFxn openFxn;

    SDSPI_CloseFxn closeFxn;

    SDSPI_ControlFxn controlFxn;
} SDSPI_FxnTable;

typedef struct SDSPI_Config_ {
    SDSPI_FxnTable const *fxnTablePtr;

    void                 *object;

    void           const *hwAttrs;
} SDSPI_Config;

extern void SDSPI_close(SDSPI_Handle handle);

extern int_fast16_t SDSPI_control(SDSPI_Handle handle, uint_fast16_t cmd,
                                  void *arg);

extern void SDSPI_init(void);

extern SDSPI_Handle SDSPI_open(uint_least8_t index, uint_least8_t drv,
                               SDSPI_Params *params);

extern void SDSPI_Params_init(SDSPI_Params *params);

#ifdef __cplusplus
}
#endif

#endif /* ti_drivers_SDSPI__include */