disk_ioctl

The disk_ioctl function is called to control device specific features and miscellaneous functions other than generic read/write.

DRESULT disk_ioctl (
  BYTE pdrv,     /* [IN] Drive number */
  BYTE cmd,      /* [IN] Control command code */
  void* buff     /* [I/O] Parameter and data buffer */
);

Parameters

pdrv
Physical drive number to identify the target device.
cmd
Command code.
buff
Pointer to the parameter depends on the command code. Do not care if the command has no parameter to be passed.

Return Value

RES_OK (0)
The function succeeded.
RES_ERROR
An error occured.
RES_PARERR
The command code or parameter is invalid.
RES_NOTRDY
The device has not been initialized.

Description

The FatFs module requires only five device independent commands described below.

Standard ioctl command used by FatFs
CommandDescription
CTRL_SYNCMake sure that the device has finished pending write process. If the disk I/O module has a write back cache, the dirty buffers must be written back to the media immediately. Nothing to do for this command if each write operation to the media is completed within the disk_write function.
GET_SECTOR_COUNTReturns number of available sectors on the drive into the DWORD variable pointed by buff. This command is used by f_mkfs and f_fdisk function to determine the volume/partition size to be created. Required at FF_USE_MKFS == 1.
GET_SECTOR_SIZEReturns sector size of the device into the WORD variable pointed by buff. Valid return values for this command are 512, 1024, 2048 and 4096. This command is required only if FF_MAX_SS > FF_MIN_SS. When FF_MAX_SS == FF_MIN_SS, this command is never used and the device must work at that sector size.
GET_BLOCK_SIZEReturns erase block size of the flash memory media in unit of sector into the DWORD variable pointed by buff. The allowable value is 1 to 32768 in power of 2. Return 1 if the erase block size is unknown or non flash memory media. This command is used by only f_mkfs function and it attempts to align data area on the erase block boundary. Required at FF_USE_MKFS == 1.
CTRL_TRIMInforms the device the data on the block of sectors is no longer needed and it can be erased. The sector block is specified by a DWORD array {<start sector>, <end sector>} pointed by buff. This is an identical command to Trim of ATA device. Nothing to do for this command if this funcion is not supported or not a flash memory device. FatFs does not check the result code and the file function is not affected even if the sector block was not erased well. This command is called on remove a cluster chain and in the f_mkfs function. Required at FF_USE_TRIM == 1.

FatFs never uses any device dependent command nor user defined command. Following table shows an example of non-standard commands which may be useful for some applications.

Example of optional ioctl command
CommandDescription
CTRL_FORMATCreate a physical format on the media. If buff is not null, it is pointer to the call-back function for progress notification.
CTRL_POWER_IDLEPut the device idle state. STA_NOINIT in the current status flags may not be set if the device goes active state by generic read/write function.
CTRL_POWER_OFFPut the device off state. Shut-down the power to the device and deinitialize the device interface if needed. STA_NOINIT in the current status flags must be set. The device goes active state by disk_initialize function.
CTRL_LOCKLock media eject mechanism.
CTRL_UNLOCKUnlock media eject mechanism.
CTRL_EJECTEject media cartridge. STA_NOINIT and STA_NODISK in status flag are set after the function succeeded.
CTRL_GET_SMARTRead SMART information.
MMC_GET_TYPEGet card type. The type flags, bit0:MMCv3, bit1:SDv1, bit2:SDv2+ and bit3:LBA, is stored to a BYTE variable pointed by buff. (MMC/SDC specific command)
MMC_GET_CSDRead CSD register into a 16-byte buffer pointed by buff. (MMC/SDC specific command)
MMC_GET_CIDRead CID register into a 16-byte buffer pointed by buff. (MMC/SDC specific command)
MMC_GET_OCRRead OCR register into a 4-byte buffer pointed by buff. (MMC/SDC specific command)
MMC_GET_SDSTATRead SDSTATUS register into a 64-byte buffer pointed by buff. (SDC specific command)
ATA_GET_REVGet the revision string into a 16-byte buffer pointed by buff. (ATA/CFC specific command)
ATA_GET_MODELGet the model string into a 40-byte buffer pointed by buff. (ATA/CFC specific command)
ATA_GET_SNGet the serial number string into a 20-byte buffer pointed by buff. (ATA/CFC specific command)
ISDIO_READRead a block of iSDIO registers specified by command structure pointed by buff. (FlashAir specific command)
ISDIO_WRITEWrite a block of data to iSDIO registers specified by command structure pointed by buff. (FlashAir specific command)
ISDIO_MRITEChange bits in an iSDIO register specified by command structure pointed by buff. (FlashAir specific command)

QuickInfo

The disk_ioctl function is not needed when FF_FS_READONLY == 1 and FF_MAX_SS == FF_MIN_SS.

Return