[BUG] FatFS + SDIO(DMA) L4

Did it pass through a user buffer that was unaligned?

I'd added this code back in the day, ST has used without attribution subsequently

/**
 * @brief Writes Sector(s)
 * @param pdrv: Physical drive number (0..)
 * @param *buff: Data to be written
 * @param sector: Sector address (LBA)
 * @param count: Number of sectors to write (1..128)
 * @retval DRESULT: Operation result
 */
#if _USE_WRITE == 1
DRESULT disk_write (
BYTE pdrv,/* Physical drive number to identify the drive */
const BYTE *buff,/* Data to be written */
DWORD sector,/* Sector address in LBA */
UINT count /* Number of sectors to write */
)
{
 SD_Error Status;
#ifdef DBG_IO
 printf('disk_write %d %p %10d %d
',pdrv,buff,sector,count);
#endif
 if (SD_Detect() != SD_PRESENT)
 return(RES_NOTRDY);
 if ((DWORD)buff & 3) // DMA Alignment failure, do single up to aligned buffer
 {
 DRESULT res = RES_OK;
 DWORD scratch[BLOCK_SIZE / 4]; // Alignment assured, you'll need a sufficiently big stack
 while(count--)
 {
 memcpy(scratch, buff, BLOCK_SIZE);
 res = disk_write(pdrv, (void *)scratch, sector++, 1);
 if (res != RES_OK)
 break;
 buff += BLOCK_SIZE;
 }
 return(res);
 }
 Status = SD_WriteMultiBlocksFIXED((uint8_t *)buff, sector, BLOCK_SIZE, count); // 4GB Compliant
 if (Status == SD_OK)
 {
 SDTransferState State;
 Status = SD_WaitWriteOperation(); // Check if the Transfer is finished
 while((State = SD_GetStatus()) == SD_TRANSFER_BUSY); // BUSY, OK (DONE), ERROR (FAIL)
 if ((State == SD_TRANSFER_ERROR) || (Status != SD_OK))
 return(RES_ERROR);
 else
 return(RES_OK);
 }
 else
 return(RES_ERROR);
}
#endif /* _USE_WRITE == 1 */
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