FATFS添加多线程支持

FATFS的多任务支持其实就是一个互斥锁管理（信号量会有优先级反转）
以ucosiii，fatfsR0.13B为例
ffconf.h修改以下下配置

#define FF_FS_REENTRANT	1   //可重入支持
#define FF_FS_TIMEOUT	1000   //超时时间
#define FF_SYNC_t		OS_MUTEX   //同步管理变量类型
/* The option FF_FS_REENTRANT switches the re-entrancy (thread safe) of the FatFs
/  module itself. Note that regardless of this option, file access to different
/  volume is always re-entrant and volume control functions, f_mount(), f_mkfs()
/  and f_fdisk() function, are always not re-entrant. Only file/directory access
/  to the same volume is under control of this function.
/
/   0: Disable re-entrancy. FF_FS_TIMEOUT and FF_SYNC_t have no effect.
/   1: Enable re-entrancy. Also user provided synchronization handlers,
/      ff_req_grant(), ff_rel_grant(), ff_del_syncobj() and ff_cre_syncobj()
/      function, must be added to the project. Samples are available in
/      option/syscall.c.
/
/  The FF_FS_TIMEOUT defines timeout period in unit of time tick.
/  The FF_SYNC_t defines O/S dependent sync object type. e.g. HANDLE, ID, OS_EVENT*,
/  SemaphoreHandle_t and etc. A header file for O/S definitions needs to be
/  included somewhere in the scope of ff.h. */

修改ffsystem.c

/*------------------------------------------------------------------------*/
/* Sample Code of OS Dependent Functions for FatFs                        */
/* (C)ChaN, 2017                                                          */
/*------------------------------------------------------------------------*/


#include "ff.h"



#if FF_USE_LFN == 3	/* Dynamic memory allocation */

/*------------------------------------------------------------------------*/
/* Allocate a memory block                                                */
/*------------------------------------------------------------------------*/

void* ff_memalloc (	/* Returns pointer to the allocated memory block (null on not enough core) */
	UINT msize		/* Number of bytes to allocate */
)
{
	return malloc(msize);	/* Allocate a new memory block with POSIX API */
}


/*------------------------------------------------------------------------*/
/* Free a memory block                                                    */
/*------------------------------------------------------------------------*/

void ff_memfree (
	void* mblock	/* Pointer to the memory block to free (nothing to do for null) */
)
{
	free(mblock);	/* Free the memory block with POSIX API */
}

#endif



#if FF_FS_REENTRANT	/* Mutal exclusion */

/*------------------------------------------------------------------------*/
/* Create a Synchronization Object                                        */
/*------------------------------------------------------------------------*/
/* This function is called in f_mount() function to create a new
/  synchronization object for the volume, such as semaphore and mutex.
/  When a 0 is returned, the f_mount() function fails with FR_INT_ERR.
*/

//const osMutexDef_t Mutex[FF_VOLUMES];	/* CMSIS-RTOS */


int ff_cre_syncobj (	/* 1:Function succeeded, 0:Could not create the sync object */
	BYTE vol,			/* Corresponding volume (logical drive number) */
	FF_SYNC_t* sobj		/* Pointer to return the created sync object */
)
{
//	/* Win32 */
//	*sobj = CreateMutex(NULL, FALSE, NULL);
//	return (int)(*sobj != INVALID_HANDLE_VALUE);

	/* uITRON */
//	T_CSEM csem = {TA_TPRI,1,1};
//	*sobj = acre_sem(&csem);
//	return (int)(*sobj > 0);

	/* uC/OS-III */
	OS_ERR err;
	
	OSMutexCreate ((OS_MUTEX*) sobj,
                     (CPU_CHAR*) "FATFS Mutex",
                     (OS_ERR*) &err);
	//return (int)(err == OS_ERR_NONE );
	return 1;

	/* FreeRTOS */
//	*sobj = xSemaphoreCreateMutex();
//	return (int)(*sobj != NULL);

	/* CMSIS-RTOS */
//	*sobj = osMutexCreate(Mutex + vol);
//	return (int)(*sobj != NULL);
}


/*------------------------------------------------------------------------*/
/* Delete a Synchronization Object                                        */
/*------------------------------------------------------------------------*/
/* This function is called in f_mount() function to delete a synchronization
/  object that created with ff_cre_syncobj() function. When a 0 is returned,
/  the f_mount() function fails with FR_INT_ERR.
*/

int ff_del_syncobj (	/* 1:Function succeeded, 0:Could not delete due to an error */
	FF_SYNC_t sobj		/* Sync object tied to the logical drive to be deleted */
)
{
//	/* Win32 */
//	return (int)CloseHandle(sobj);

	/* uITRON */
//	return (int)(del_sem(sobj) == E_OK);

	/* uC/OS-III */
	OS_ERR err;
	OSMutexDel(&sobj, OS_OPT_DEL_ALWAYS, &err);
	return (int)(err == OS_ERR_NONE );

	/* FreeRTOS */
//  vSemaphoreDelete(sobj);
//	return 1;

	/* CMSIS-RTOS */
//	return (int)(osMutexDelete(sobj) == osOK);
}


/*------------------------------------------------------------------------*/
/* Request Grant to Access the Volume                                     */
/*------------------------------------------------------------------------*/
/* This function is called on entering file functions to lock the volume.
/  When a 0 is returned, the file function fails with FR_TIMEOUT.
*/

int ff_req_grant (	/* 1:Got a grant to access the volume, 0:Could not get a grant */
	FF_SYNC_t sobj	/* Sync object to wait */
)
{
//	/* Win32 */
//	return (int)(WaitForSingleObject(sobj, FF_FS_TIMEOUT) == WAIT_OBJECT_0);

	/* uITRON */
//	return (int)(wai_sem(sobj) == E_OK);

	/* uC/OS-III */
	OS_ERR err;

	OSMutexPend(&sobj,FF_FS_TIMEOUT, OS_OPT_PEND_BLOCKING,0, &err);
	return (int)(err == OS_ERR_NONE );

	/* FreeRTOS */
//	return (int)(xSemaphoreTake(sobj, FF_FS_TIMEOUT) == pdTRUE);

	/* CMSIS-RTOS */
//	return (int)(osMutexWait(sobj, FF_FS_TIMEOUT) == osOK);
}


/*------------------------------------------------------------------------*/
/* Release Grant to Access the Volume                                     */
/*------------------------------------------------------------------------*/
/* This function is called on leaving file functions to unlock the volume.
*/

void ff_rel_grant (
	FF_SYNC_t sobj	/* Sync object to be signaled */
)
{
//	/* Win32 */
//	ReleaseMutex(sobj);

	/* uITRON */
//	sig_sem(sobj);

	/* uC/OS-III */
	OS_ERR err;
 OSMutexPost ((OS_MUTEX*) &sobj,
                   (OS_OPT)     OS_OPT_POST_NONE,					//²»Ö´ÐÐÌØÊâ²Ù×÷£¬¼´²»½ûÖ¹µ÷¶È
                   (OS_ERR*)    &err);
	/* FreeRTOS */
//	xSemaphoreGive(sobj);

	/* CMSIS-RTOS */
//	osMutexRelease(sobj);
}

#endif