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 */ );
The FatFs module requires only five device independent commands described below.
Command | Description |
---|---|
CTRL_SYNC | Makes sure that the device has finished pending write process. If the disk I/O layer or storage device has a write-back cache, the dirty cache data must be committed to the medium immediately. Nothing to do for this command if each write operation to the medium is completed in the disk_write function. |
GET_SECTOR_COUNT | Retrieves number of available sectors, the largest allowable LBA + 1, on the drive into the LBA_t variable that pointed by buff. This command is used by f_mkfs and f_fdisk function to determine the size of volume/partition to be created. |
GET_SECTOR_SIZE | Retrieves sector size, minimum data unit for generic read/write, into the WORD variable that pointed by buff. Valid sector sizes 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 will never be used and the disk_read and disk_write function must work in FF_MAX_SS bytes/sector. |
GET_BLOCK_SIZE | Retrieves erase block size in unit of sector of the flash memory media into the DWORD variable that pointed by buff. The allowable value is 1 to 32768 in power of 2. Return 1 if it is unknown or in non flash memory media. This command is used by f_mkfs function with block size not specified and it attempts to align the data area on the suggested block boundary. Note that FatFs does not have FTL (flash translation layer), so that either disk I/O layter or storage device must have an FTL in it. |
CTRL_TRIM | Informs the disk I/O layter or the storage device that the data on the block of sectors is no longer needed and it can be erased. The sector block is specified in an LBA_t array {<Start LBA>, <End LBA>} that 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. It is required when FF_USE_TRIM == 1. |
FatFs will never use any device dependent command nor user defined command. Following table shows an example of non-standard commands which may be useful for some applications.
Command | Description |
---|---|
CTRL_FORMAT | Creates a physical format on the media. If buff is not null, it is pointer to the call-back function for progress notification. |
CTRL_POWER_IDLE | Puts 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_OFF | Puts 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_LOCK | Locks media eject mechanism. |
CTRL_UNLOCK | Unlocks media eject mechanism. |
CTRL_EJECT | Ejects media cartridge. STA_NOINIT and STA_NODISK in status flag are set after the function succeeds. |
CTRL_GET_SMART | Reads SMART information. |
MMC_GET_TYPE | Gets 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_CSD | Reads CSD register and sets it into a 16-byte buffer pointed by buff. (MMC/SDC specific command) |
MMC_GET_CID | Reads CID register and sets it into a 16-byte buffer pointed by buff. (MMC/SDC specific command) |
MMC_GET_OCR | Reads OCR register and sets it into a 4-byte buffer pointed by buff. (MMC/SDC specific command) |
MMC_GET_SDSTAT | Reads SDSTATUS register and sets it into a 64-byte buffer pointed by buff. (SDC specific command) |
ATA_GET_REV | Reads the revision string and sets it into a 16-byte buffer pointed by buff. (ATA/CFC specific command) |
ATA_GET_MODEL | Reads the model string and sets it into a 40-byte buffer pointed by buff. (ATA/CFC specific command) |
ATA_GET_SN | Reads the serial number string and sets it into a 20-byte buffer pointed by buff. (ATA/CFC specific command) |
ISDIO_READ | Reads a block of iSDIO registers specified by command structure pointed by buff. (FlashAir specific command) |
ISDIO_WRITE | Writes a block of data to iSDIO registers specified by command structure pointed by buff. (FlashAir specific command) |
ISDIO_MRITE | Changes bits in an iSDIO register specified by command structure pointed by buff. (FlashAir specific command) |
The disk_ioctl function is not needed when FF_FS_READONLY == 1 and FF_MAX_SS == FF_MIN_SS.