scsi.4 revision 13744
1249423Sdim.Dd August 27, 1993 2224135Sdim.Dt SD 4 3224135Sdim.Os FreeBSD 4224135Sdim.Sh NAME 5224135Sdim.Nm scsi 6224135Sdim.Nd scsi system 7224135Sdim.Sh SYNOPSIS 8224135Sdim.Nm controller scbus0 9224135Sdim.Nm controller scbus1 at ahc0 10224135Sdim.Nm controller scbus3 at ahc1 bus 0 11224135Sdim.Nm controller scbus2 at ahc1 bus 1 12224135Sdim.Nm device cd0 13224135Sdim.Nm device ch0 14224135Sdim.Nm disk sd0 15224135Sdim.Nm tape st0 16224135Sdim.Nm device ch1 at scbus0 target 4 unit 0 17224135Sdim.Sh DESCRIPTION 18224135SdimThe 19224135Sdim.Em scsi 20224135Sdimsystem provides a uniform and modular system for the implementation 21224135Sdimof drivers to control various scsi devices, and to utilize different 22224135Sdimscsi host adapters through host adapter drivers. When the system probes the 23224135Sdim.Em SCSI 24224135Sdimbusses, it attaches any devices it finds to the appropriate 25224135Sdimdrivers. If no driver seems appropriate, then it attaches the device to the 26224135Sdimuk (unknown) driver so that user level scsi ioctls may 27224135Sdimstill be performed against the device. 28224135Sdim.Sh KERNEL CONFIGURATION 29224135SdimThe option SCSIDEBUG enables the debug ioctl. 30224135Sdim.Pp 31224135SdimAll devices and the SCSI busses support boot time allocation so that 32224135Sdiman upper number of devices and controllers does not need to be configured; 33224135Sdim.Em "device sd0" 34224135Sdimwill suffice for any number of disk drivers. 35224135Sdim.Pp 36224135SdimThe devices are either 37249423Sdim.Em wired 38224135Sdimso they appear as a particular device unit or 39224135Sdim.Em counted 40224135Sdimso that they appear as the next available unused unit. 41224135Sdim.Pp 42224135SdimTo configure a driver in the kernel without wiring down the device use a 43224135Sdimconfig line similar to 44224135Sdim.Em "device ch0" 45224135Sdimto include the changer driver. 46224135Sdim.Pp 47234353SdimTo wire down a unit use a config line similar to 48224135Sdim.Em "device ch1 at scbus0 target 4 unit 0" 49226633Sdimto assign changer 1 as the changer with SCSI ID 4, 50234353SdimSCSI logical unit 0 on SCSI bus 0. 51234353SdimIndividual scbuses can be wired down to specific controllers with 52234353Sdima config line similar to 53234353Sdim.Em "controller scbus0 at ahc0" 54234353Sdimwhich assigns scsi bus 0 to the first unit using the ahc driver. 55234353SdimFor controllers supporting more than one bus, 56234353Sdimthe particular bus can be specified as in 57234353Sdim.Em "controller scbus3 at ahc1 bus 1" 58224135Sdimwhich assigns scbus 1 to the second bus probed on the ahc1 device. 59224135Sdim.Pp 60224135SdimWhen you have a mixture of wired down and counted devices then the 61224135Sdimcounting begins with the first non-wired down unit for a particular 62224135Sdimtype. That is, if you have a disk wired down as 63224135Sdim.Em "disk sd1" , 64224135Sdimthen the first non-wired disk shall come on line as 65224135Sdim.Em sd2 . 66224135Sdim.Sh IOCTLS 67226633SdimThere are a number of ioctls that work on any 68224135Sdim.Em SCSI 69224135Sdimdevice. They are defined in 70234353Sdim.Em sys/scsiio.h 71224135Sdimand can be applied against any scsi device that permits them. 72224135SdimFor the tape, it must be applied against the control 73234353Sdimdevice. See the manual page for each device type for more information about 74234353Sdimhow generic scsi ioctls may be applied to a specific device. 75224135Sdim.Bl -tag -width DIOCSDINFO____ 76234353Sdim.It Dv SCIOCRESET* 77234353Sdimreset a device. 78234353Sdim.It Dv SCIOCDEBUG 79234353SdimTurn on debugging.. All scsi operations originating from this device's driver 80234353Sdimwill be traced to the console, along with other information. Debugging is 81234353Sdimcontrolled by four bits, described in the header file. If no debugging is 82234353Sdimconfigured into the kernel, debugging will have no effect. 83234353Sdim.Em SCSI 84234353Sdimdebugging is controlled by the configuration option 85234353Sdim.Em SCSIDEBUG. 86234353Sdim.It Dv SCIOCCOMMAND 87234353SdimTake a scsi command and data from a user process and apply them to the scsi 88234353Sdimdevice. Return all status information and return data to the process. The 89234353Sdimioctl will return a successful status even if the device rejected the 90234353Sdimcommand. As all status is returned to the user, it is up to the user 91234353Sdimprocess to examine this information to decide the success of the command. 92224135Sdim.It Dv SCIOCREPROBE 93226633SdimAsk the system to probe the scsi busses for any new devices. If it finds 94224135Sdimany, they will be attached to the appropriate drivers. The search can be 95224135Sdimnarrowed to a specific bus, target or lun. The new device may or may not 96224135Sdimbe related to the device on which the ioctl was performed. 97224135Sdim.It Dv SCIOCIDENTIFY 98234353SdimAsk the driver what it's bus, target and lun are. 99224135Sdim.It Dv SCIOCDECONFIG 100224135SdimAsk the device to disappear. This may not happen if the device is in use. 101224135Sdim.El 102224135Sdim.Sh NOTES 103224135Sdimthe generic scsi part of the system is still being mapped out. 104224135SdimWatch this space for changes. 105224135Sdim.Pp 106224135Sdim A device by the name of su (scsi_user) 107224135Sdim(e.g su0-0-0) will map bus, target and lun to minor numbers. I have not 108224135Sdimyet decided yet whether this device will be able to open a device that is 109224135Sdimalready controlled by an explicit driver. 110224135Sdim.Sh ADAPTERS 111224135SdimThe system allows common device drivers to work through many different 112224135Sdimtypes of adapters. The adapters take requests from the upper layers and do 113224135Sdimall IO between the 114224135Sdim.Em SCSI 115224135Sdimbus and the system. The maximum size of a transfer is governed by the 116224135Sdimadapter. Most adapters can transfer 64KB in a single operation, however 117224135Sdimmany can transfer larger amounts. 118224135Sdim.Sh TARGET MODE 119224135SdimSome adapters support 120224135Sdim.Em Target mode 121224135Sdimin which the system is capable of operating as a device, responding to 122224135Sdimoperations initiated by another system. Target mode will be supported for 123224135Sdimsome adapters, but is not yet complete for this version of the scsi system. 124224135Sdim.Sh FILES 125224135Sdimsee other scsi device entries. 126224135Sdim.Sh DIAGNOSTICS 127224135SdimWhen the kernel is compiled with option SCSIDEBUG, the SCIOCDEBUG ioctl 128224135Sdimcan be used to enable various amounts of tracing information on any 129224135Sdimspecific device. Devices not being traced will not produce trace information. 130224135SdimThe four bits that make up the debug level, each control certain types 131224135Sdimof debugging information. 132224135Sdim.Bl -tag -width THIS_WIDE_PLEASE 133234353Sdim.It Dv Bit 0 134224135SdimBit 0 shows all scsi bus operations including scsi commands, 135234353Sdimerror information and the first 48 bytes of any data transferred. 136224135Sdim.It Dv Bit 1 137224135SdimBit 1 shows routines called. 138224135Sdim.It Dv Bit 2 139224135SdimBit 2 shows information about what branches are taken and often some 140224135Sdimof the return values of functions. 141234353Sdim.It Dv Bit 3 142234353SdimBit 3 shows more detailed information including DMA scatter-gather logs. 143234353Sdim.El 144249423Sdim.Sh SEE ALSO 145249423Sdim.Xr ch 4 146249423Sdim.Xr cd 4 147249423Sdim.Xr sd 4 148249423Sdim.Xr st 4 149249423Sdim.Xr uk 4 150234353Sdim.Xr su 4 151234353Sdim.Xr aha 4 152234353Sdim.Xr ahb 4 153234353Sdim.Xr bt 4 154234353Sdim.Xr uha 4 155234353Sdim.Sh HISTORY 156234353SdimThis 157234353Sdim.Nm 158224135Sdimsystem appeared in MACH 2.5 at TRW. 159224135Sdim 160224135Sdim