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+Ioctl Numbers
+19 October 1999
+Michael Elizabeth Chastain
+<mec@shout.net>
+
+If you are adding new ioctl's to the kernel, you should use the _IO
+macros defined in <linux/ioctl.h>:
+
+ _IO an ioctl with no parameters
+ _IOW an ioctl with write parameters (copy_from_user)
+ _IOR an ioctl with read parameters (copy_to_user)
+ _IOWR an ioctl with both write and read parameters.
+
+'Write' and 'read' are from the user's point of view, just like the
+system calls 'write' and 'read'. For example, a SET_FOO ioctl would
+be _IOW, although the kernel would actually read data from user space;
+a GET_FOO ioctl would be _IOR, although the kernel would actually write
+data to user space.
+
+The first argument to _IO, _IOW, _IOR, or _IOWR is an identifying letter
+or number from the table below. Because of the large number of drivers,
+many drivers share a partial letter with other drivers.
+
+If you are writing a driver for a new device and need a letter, pick an
+unused block with enough room for expansion: 32 to 256 ioctl commands.
+You can register the block by patching this file and submitting the
+patch to Linus Torvalds. Or you can e-mail me at <mec@shout.net> and
+I'll register one for you.
+
+The second argument to _IO, _IOW, _IOR, or _IOWR is a sequence number
+to distinguish ioctls from each other. The third argument to _IOW,
+_IOR, or _IOWR is the type of the data going into the kernel or coming
+out of the kernel (e.g. 'int' or 'struct foo'). NOTE! Do NOT use
+sizeof(arg) as the third argument as this results in your ioctl thinking
+it passes an argument of type size_t.
+
+Some devices use their major number as the identifier; this is OK, as
+long as it is unique. Some devices are irregular and don't follow any
+convention at all.
+
+Following this convention is good because:
+
+(1) Keeping the ioctl's globally unique helps error checking:
+ if a program calls an ioctl on the wrong device, it will get an
+ error rather than some unexpected behaviour.
+
+(2) The 'strace' build procedure automatically finds ioctl numbers
+ defined with _IO, _IOW, _IOR, or _IOWR.
+
+(3) 'strace' can decode numbers back into useful names when the
+ numbers are unique.
+
+(4) People looking for ioctls can grep for them more easily when
+ this convention is used to define the ioctl numbers.
+
+(5) When following the convention, the driver code can use generic
+ code to copy the parameters between user and kernel space.
+
+This table lists ioctls visible from user land for Linux/i386. It contains
+most drivers up to 2.3.14, but I know I am missing some.
+
+Code Seq# Include File Comments
+========================================================
+0x00 00-1F linux/fs.h conflict!
+0x00 00-1F scsi/scsi_ioctl.h conflict!
+0x00 00-1F linux/fb.h conflict!
+0x00 00-1F linux/wavefront.h conflict!
+0x02 all linux/fd.h
+0x03 all linux/hdreg.h
+0x04 all linux/umsdos_fs.h
+0x06 all linux/lp.h
+0x09 all linux/md.h
+0x12 all linux/fs.h
+ linux/blkpg.h
+0x1b all InfiniBand Subsystem <http://www.openib.org/>
+0x20 all drivers/cdrom/cm206.h
+0x22 all scsi/sg.h
+'#' 00-3F IEEE 1394 Subsystem Block for the entire subsystem
+'1' 00-1F <linux/timepps.h> PPS kit from Ulrich Windl
+ <ftp://ftp.de.kernel.org/pub/linux/daemons/ntp/PPS/>
+'6' 00-10 <asm-i386/processor.h> Intel IA32 microcode update driver
+ <mailto:tigran@veritas.com>
+'8' all SNP8023 advanced NIC card
+ <mailto:mcr@solidum.com>
+'A' 00-1F linux/apm_bios.h
+'B' C0-FF advanced bbus
+ <mailto:maassen@uni-freiburg.de>
+'C' all linux/soundcard.h
+'D' all asm-s390/dasd.h
+'F' all linux/fb.h
+'I' all linux/isdn.h
+'J' 00-1F drivers/scsi/gdth_ioctl.h
+'K' all linux/kd.h
+'L' 00-1F linux/loop.h
+'L' E0-FF linux/ppdd.h encrypted disk device driver
+ <http://linux01.gwdg.de/~alatham/ppdd.html>
+'M' all linux/soundcard.h conflict!
+'M' 00-1F linux/isicom.h conflict!
+'N' 00-1F drivers/usb/scanner.h
+'P' all linux/soundcard.h
+'Q' all linux/soundcard.h
+'R' 00-1F linux/random.h
+'S' all linux/cdrom.h conflict!
+'S' 80-81 scsi/scsi_ioctl.h conflict!
+'S' 82-FF scsi/scsi.h conflict!
+'T' all linux/soundcard.h conflict!
+'T' all asm-i386/ioctls.h conflict!
+'U' 00-EF linux/drivers/usb/usb.h
+'U' F0-FF drivers/usb/auerswald.c
+'V' all linux/vt.h
+'W' 00-1F linux/watchdog.h conflict!
+'W' 00-1F linux/wanrouter.h conflict!
+'X' all linux/xfs_fs.h
+'Y' all linux/cyclades.h
+'a' all ATM on linux
+ <http://lrcwww.epfl.ch/linux-atm/magic.html>
+'b' 00-FF bit3 vme host bridge
+ <mailto:natalia@nikhefk.nikhef.nl>
+'c' 00-7F linux/comstats.h conflict!
+'c' 00-7F linux/coda.h conflict!
+'d' 00-FF linux/char/drm/drm/h conflict!
+'d' 00-1F linux/devfs_fs.h conflict!
+'d' 00-DF linux/video_decoder.h conflict!
+'d' F0-FF linux/digi1.h
+'e' all linux/digi1.h conflict!
+'e' 00-1F linux/video_encoder.h conflict!
+'e' 00-1F net/irda/irtty.h conflict!
+'f' 00-1F linux/ext2_fs.h
+'h' 00-7F Charon filesystem
+ <mailto:zapman@interlan.net>
+'i' 00-3F linux/i2o.h
+'j' 00-3F linux/joystick.h
+'k' all asm-sparc/kbio.h
+ asm-sparc64/kbio.h
+'l' 00-3F linux/tcfs_fs.h transparent cryptographic file system
+ <http://mikonos.dia.unisa.it/tcfs>
+'l' 40-7F linux/udf_fs_i.h in development:
+ <http://www.trylinux.com/projects/udf/>
+'m' all linux/mtio.h conflict!
+'m' all linux/soundcard.h conflict!
+'m' all linux/synclink.h conflict!
+'m' 00-1F net/irda/irmod.h conflict!
+'n' 00-7F linux/ncp_fs.h
+'n' E0-FF video/matrox.h matroxfb
+'p' 00-3F linux/mc146818rtc.h
+'p' 40-7F linux/nvram.h
+'p' 80-9F user-space parport
+ <mailto:tim@cyberelk.net>
+'q' 00-1F linux/serio.h
+'q' 80-FF Internet PhoneJACK, Internet LineJACK
+ <http://www.quicknet.net>
+'r' 00-1F linux/msdos_fs.h
+'s' all linux/cdk.h
+'t' 00-7F linux/if_ppp.h
+'t' 80-8F linux/isdn_ppp.h
+'u' 00-1F linux/smb_fs.h
+'v' 00-1F linux/ext2_fs.h conflict!
+'v' all linux/videodev.h conflict!
+'w' all CERN SCI driver
+'y' 00-1F packet based user level communications
+ <mailto:zapman@interlan.net>
+'z' 00-3F CAN bus card
+ <mailto:hdstich@connectu.ulm.circular.de>
+'z' 40-7F CAN bus card
+ <mailto:oe@port.de>
+0x80 00-1F linux/fb.h
+0x81 00-1F linux/videotext.h
+0x89 00-06 asm-i386/sockios.h
+0x89 0B-DF linux/sockios.h
+0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range
+0x89 F0-FF linux/sockios.h SIOCDEVPRIVATE range
+0x8B all linux/wireless.h
+0x8C 00-3F WiNRADiO driver
+ <http://www.proximity.com.au/~brian/winradio/>
+0x90 00 drivers/cdrom/sbpcd.h
+0x93 60-7F linux/auto_fs.h
+0x99 00-0F 537-Addinboard driver
+ <mailto:buk@buks.ipn.de>
+0xA0 all linux/sdp/sdp.h Industrial Device Project
+ <mailto:kenji@bitgate.com>
+0xA3 80-8F Port ACL in development:
+ <mailto:tlewis@mindspring.com>
+0xA3 90-9F linux/dtlk.h
+0xAB 00-1F linux/nbd.h
+0xAC 00-1F linux/raw.h
+0xAD 00 Netfilter device in development:
+ <mailto:rusty@rustcorp.com.au>
+0xB0 all RATIO devices in development:
+ <mailto:vgo@ratio.de>
+0xB1 00-1F PPPoX <mailto:mostrows@styx.uwaterloo.ca>
+0xCB 00-1F CBM serial IEC bus in development:
+ <mailto:michael.klein@puffin.lb.shuttle.de>
+0xDD 00-3F ZFCP device driver see drivers/s390/scsi/
+ <mailto:aherrman@de.ibm.com>
+0xF3 00-3F video/sisfb.h sisfb (in development)
+ <mailto:thomas@winischhofer.net>