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/*------------------------------------------------------------------------*/
/* Sample Code of OS Dependent Functions for FatFs                        */
/* (C)ChaN, 2018                                                          */
/*------------------------------------------------------------------------*/


#include "fatFs/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 if not enough core) */
	UINT msize		/* Number of bytes to allocate */
)
{
#if defined portENTER_CRITICAL
  return pvPortMalloc(msize);
#else
	return malloc(msize);	/* Allocate a new memory block with POSIX API */
#endif
}


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

void ff_memfree (
	void* mblock	/* Pointer to the memory block to free (nothing to do if null) */
)
{
#if defined portENTER_CRITICAL
  vPortFree(mblock);
#else
	free(mblock);	/* Free the memory block with POSIX API */
#endif
}

#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];	/* Table of CMSIS-RTOS mutex */


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 */
)
{
#if defined(_WIN32) /* Win32 */
	*sobj = CreateMutex(NULL, FALSE, NULL);
	return (int)(*sobj != INVALID_HANDLE_VALUE);
#endif

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

	/* uC/OS-II */
//	OS_ERR err;
//	*sobj = OSMutexCreate(0, &err);
//	return (int)(err == OS_NO_ERR);

#if defined(portENTER_CRITICAL)   /* FreeRTOS */
	(void)vol;
	*sobj = xSemaphoreCreateMutex();
	return (int)(*sobj != NULL);
#endif

#if defined(osCMSIS) /* CMSIS-RTOS */
	*sobj = osMutexCreate(&Mutex[vol]);
	return (int)(*sobj != NULL);
#endif
}


/*------------------------------------------------------------------------*/
/* 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 */
)
{
#if defined(_WIN32) /* Win32 */
	return (int)CloseHandle(sobj);
#endif

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

	/* uC/OS-II */
//	OS_ERR err;
//	OSMutexDel(sobj, OS_DEL_ALWAYS, &err);
//	return (int)(err == OS_NO_ERR);

#if defined(portENTER_CRITICAL)   /* FreeRTOS */
  vSemaphoreDelete(sobj);
	return 1;
#endif

#if defined(osCMSIS) /* CMSIS-RTOS */
	return (int)(osMutexDelete(sobj) == osOK);
#endif
}


/*------------------------------------------------------------------------*/
/* 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 */
)
{
#if defined(_WIN32) /* Win32 */
	return (int)(WaitForSingleObject(sobj, FF_FS_TIMEOUT) == WAIT_OBJECT_0);
#endif

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

	/* uC/OS-II */
//	OS_ERR err;
//	OSMutexPend(sobj, FF_FS_TIMEOUT, &err));
//	return (int)(err == OS_NO_ERR);

#if defined(portENTER_CRITICAL)   /* FreeRTOS */
	return (int)(xSemaphoreTake(sobj, FF_FS_TIMEOUT) == pdTRUE);
#endif

#if defined(osCMSIS) /* CMSIS-RTOS */
	return (int)(osMutexWait(sobj, FF_FS_TIMEOUT) == osOK);
#endif
}


/*------------------------------------------------------------------------*/
/* 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 */
)
{
#if defined(_WIN32) /* Win32 */
	ReleaseMutex(sobj);
#endif

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

	/* uC/OS-II */
//	OSMutexPost(sobj);

#if defined(portENTER_CRITICAL)   /* FreeRTOS */
	xSemaphoreGive(sobj);
#endif

#if defined(osCMSIS) /* CMSIS-RTOS */
	osMutexRelease(sobj);
#endif
}

#endif

DRESULT disk_read (
	BYTE pdrv,		/* Physical drive nmuber to identify the drive */
	BYTE *buff,		/* Data buffer to store read data */
	LBA_t sector,	/* Start sector in LBA */
	UINT count		/* Number of sectors to read */
)
{
    FILE* fp = fopen("img.bin", "rb");
    fseek(fp, sector * FF_MIN_SS, SEEK_SET);
    fread(buff, FF_MIN_SS, count, fp);
    fclose(fp);
    return 0;
}

static FRESULT mount_volume (){    # file: ff.c,  line: 33323
    ...
		nclst = (tsect - sysect) / fs->csize;			/* Number of clusters */
		if (nclst == 0) return FR_NO_FILESYSTEM;
		fmt = 0;
		if (nclst <= MAX_FAT32) fmt = FS_FAT32;        
		if (nclst <= MAX_FAT16) fmt = FS_FAT16;   // my image size  is 32MB, it set fmt equal to FS_FAT16
		if (nclst <= MAX_FAT12) fmt = FS_FAT12;
		if (fmt == 0) return FR_NO_FILESYSTEM;
               ...
		if (fmt == FS_FAT32) {
			if (ld_word(fs->win + BPB_FSVer32) != 0) return FR_NO_FILESYSTEM;
			if (fs->n_rootdir != 0) return FR_NO_FILESYSTEM;    // logic different, in other cases(FAT16?)
			fs->dirbase = ld_dword(fs->win + BPB_RootClus32);	
			szbfat = fs->n_fatent * 4;					
		} else {
			if (fs->n_rootdir == 0)	return FR_NO_FILESYSTEM;   // touch here, then return 13, means mount failed 
			fs->dirbase = fs->fatbase + fasize;		
			szbfat = (fmt == FS_FAT16) ?				
				fs->n_fatent * 2 : fs->n_fatent * 3 / 2 + (fs->n_fatent & 1);
		}
    ...
}