/*-----------------------------------------------------------------------*/
/* Low level disk I/O module skeleton for FatFs     (C)ChaN, 2007        */
/*-----------------------------------------------------------------------*/
/* This is a stub disk I/O module that acts as front end of the existing */
/* disk I/O modules and attach it to FatFs module with common interface. */
/*-----------------------------------------------------------------------*/

#include "../../gfx.h"

#if GFX_USE_GFILE && GFILE_NEED_PETITFS && GFX_USE_OS_CHIBIOS && !GFILE_PETITFS_EXTERNAL_LIB

#include "gfile_petitfs_wrapper.h"
#include <string.h>

#if HAL_USE_MMC_SPI && HAL_USE_SDC
	#error "cannot specify both MMC_SPI and SDC drivers"
#endif

#if HAL_USE_MMC_SPI
	extern MMCDriver MMCD1;
#elif HAL_USE_SDC
	extern SDCDriver SDCD1;
#else
	#error "MMC_SPI or SDC driver must be specified"
#endif

// WOW - Bugs galore!!! (in ChibiOS)
//	Bugs:
//		1. ChibiOS DMA operations do not do the appropriate cache flushing or invalidating
//			on cpu's that require it eg STM32F7 series.
//			Instead they provide explicit dmaBufferInvalidate and dmaBufferFlush calls
//			and rely on the user to explicitly flush the cache.
//			Solution: We explicitly flush the cache after any possible DMA operation.
//		2. Unfortunately these explicit routines also have a bug. They assume that the
//			specified data structure is aligned on a cache line boundary - not a good assumption.
//			Solution: We increase the size provided to ChibiOS so that it does it properly.
//						This assumes of course that we know the size of the cpu cache line.
#if CH_KERNEL_MAJOR > 2
	#define CPU_CACHE_LINE_SIZE			32
	#define CACHE_FLUSH(buf, sz)		dmaBufferFlush((buf), (sz)+(CPU_CACHE_LINE_SIZE-1))
	#define CACHE_INVALIDATE(buf, sz)	dmaBufferInvalidate((buf), (sz)+(CPU_CACHE_LINE_SIZE-1))
#else
	#define CACHE_FLUSH(buf, sz)
	#define CACHE_INVALIDATE(buf, sz)
#endif

/*-----------------------------------------------------------------------*/
/* Initialize a Drive                                                    */

DSTATUS disk_initialize (void) {
#if HAL_USE_MMC_SPI
    /* It is initialized externally, just reads the status.*/
    if (blkGetDriverState(&MMCD1) != BLK_READY)
    	return STA_NOINIT;
#else
    /* It is initialized externally, just reads the status.*/
    if (blkGetDriverState(&SDCD1) != BLK_READY)
    	return STA_NOINIT;
#endif
    // All good
	return 0;
}

/*-----------------------------------------------------------------------*/
/* Read Part Sector(s)                                                        */

static BYTE		sectBuf[512];
static DWORD	sectpos = -1;

DRESULT disk_readp (
		BYTE* buff,    /* [OUT] Pointer to the read buffer */
		DWORD sector,  /* [IN]  Sector number */
		UINT offset,   /* [IN]  Byte offset in the sector to start to read */
		UINT count     /* [IN]  Number of bytes to read */
		) {

	if (sector != sectpos) {
		#if HAL_USE_MMC_SPI
			if (blkGetDriverState(&MMCD1) != BLK_READY)
				return RES_NOTRDY;
			if (mmcStartSequentialRead(&MMCD1, sector))
				return RES_ERROR;
			if (mmcSequentialRead(&MMCD1, sectBuf))
				return RES_ERROR;
			if (mmcStopSequentialRead(&MMCD1))
				return RES_ERROR;
		#else
			if (blkGetDriverState(&SDCD1) != BLK_READY)
				return RES_NOTRDY;
			if (sdcRead(&SDCD1, sector, sectBuf, 1))
				return RES_ERROR;
		#endif
		sectpos = sector;
		CACHE_INVALIDATE(sectBuf, sizeof(sectBuf));
	}
	memcpy(buff, sectBuf + offset, count);
	return RES_OK;
}

#endif // GFX_USE_GFILE && GFILE_NEED_PETITFS && GFX_USE_OS_CHIBIOS && !GFILE_PETITFS_EXTERNAL_LIB