bsd/man/man4/scsi.4

   1 .\"     $OpenBSD: scsi.4,v 1.1 1996/08/04 20:28:20 tholo Exp $
   2 .\"
   3 .Dd August 4, 1996
   4 .Dt SD 4
   5 .Os OpenBSD
   6 .Sh NAME
   7 .Nm scsi
   8 .Nd scsi system
   9 .Sh SYNOPSIS
  10 .Nm scsibus* at aha?
  11 .Nm scsibus* at ncr?
  12 .Nm device cd* at scsibus? target ? lun ?
  13 .Nm device ch* at scsibus? target ? lun ?
  14 .Nm device sd* at scsibus? target ? lun ?
  15 .Nm device st* at scsibus? target ? lun ?
  16 .Nm device ss* at scsibus? target ? lun ?
  17 .Nm device su* at scsibus? target ? lun ?
  18 .Nm device uk* at scsibus? target ? lun ?
  19 .Sh DESCRIPTION
  20 The
  21 .Em scsi
  22 system provides a uniform and modular system for the implementation
  23 of drivers to control various scsi devices, and to utilize different
  24 scsi host adapters through host adapter drivers. When the system probes the
  25 .Em SCSI
  26 busses, it attaches any devices it finds to the appropriate
  27 drivers. If no driver seems appropriate, then it attaches the device to the
  28 uk (unknown) driver so that user level scsi ioctls may
  29 still be performed against the device.
  30 .Sh KERNEL CONFIGURATION
  31 The option SCSIDEBUG enables the debug ioctl.
  32 .Pp
  33 All devices and the SCSI busses support boot time allocation so that
  34 an upper number of devices and controllers does not need to be configured;
  35 .Em "device sd* at scsibus? target ? lun ?"
  36 will suffice for any number of disk drivers.
  37 .Pp
  38 The devices are either
  39 .Em wired
  40 so they appear as a particular device unit or
  41 .Em counted
  42 so that they appear as the next available unused unit.
  43 .Pp
  44 To configure a driver in the kernel without wiring down the device use a
  45 config line similar to
  46 .Em "device ch* at scsibus? target ? lun ?"
  47 to include the changer driver.
  48 .Pp
  49 To wire down a unit use a config line similar to
  50 .Em "device ch1 at scsibus0 target 4 lun 0"
  51 to assign changer 1 as the changer with SCSI ID 4,
  52 SCSI logical unit 0 on SCSI bus 0.
  53 Individual scsibuses can be wired down to specific controllers with
  54 a config line similar to
  55 .Em "scsibus0 at ahc0"
  56 which assigns scsi bus 0 to the first unit using the ahc driver.
  57 For controllers supporting more than one bus,
  58 the particular bus can be specified as in
  59 .Em "scsibus3 at ahc1 bus 1"
  60 which assigns scsibus 1 to the second bus probed on the ahc1 device.
  61 .Pp
  62 When you have a mixture of wired down and counted devices then the
  63 counting begins with the first non-wired down unit for a particular
  64 type.  That is, if you have a disk wired down as
  65 .Em "disk sd1 at scsibus? target ? lun ?" ,
  66 then the first non-wired disk shall come on line as
  67 .Em sd2 .
  68 .Sh IOCTLS
  69 There are a number of ioctls that work on any
  70 .Em SCSI
  71 device. They are defined in
  72 .Em sys/scsiio.h
  73 and can be applied against any scsi device that permits them.
  74 For the tape, it must be applied against the control
  75 device. See the manual page for each device type for more information about
  76 how generic scsi ioctls may be applied to a specific device.
  77 .Bl -tag -width DIOCSDINFO____
  78 .It Dv SCIOCRESET*
  79 reset a device.
  80 .It Dv SCIOCDEBUG
  81 Turn on debugging.. All scsi operations originating from this device's driver
  82 will be traced to the console, along with other information. Debugging is
  83 controlled by four bits, described in the header file. If no debugging is
  84 configured into the kernel, debugging will have no effect.
  85 .Em SCSI
  86 debugging is controlled by the configuration option
  87 .Em SCSIDEBUG.
  88 .It Dv SCIOCCOMMAND
  89 Take a scsi command and data from a user process and apply them to the scsi
  90 device. Return all status information and return data to the process. The
  91 ioctl will return a successful status even if the device rejected the
  92 command. As all status is returned to the user, it is up to the user
  93 process to examine this information to decide the success of the command.
  94 .It Dv SCIOCREPROBE
  95 Ask the system to probe the scsi busses for any new devices. If it finds
  96 any, they will be attached to the appropriate drivers. The search can be
  97 narrowed to a specific bus, target or lun. The new device may or may not
  98 be related to the device on which the ioctl was performed.
  99 .It Dv SCIOCIDENTIFY
 100 Ask the driver what it's bus, target and lun are.
 101 .It Dv SCIOCDECONFIG
 102 Ask the device to disappear. This may not happen if the device is in use.
 103 .El
 104 .Sh NOTES
 105 the generic scsi part of the system is still being mapped out.
 106 Watch this space for changes.
 107 .Pp
 108  A device by the name of su (scsi_user)
 109 (e.g  su0-0-0) will map bus, target and lun to  minor numbers. It has not
 110 yet decided yet whether this device will be able to open a device that is
 111 already controlled by an explicit driver.
 112 .Sh ADAPTERS
 113 The system allows common device drivers to work through many different
 114 types of adapters. The adapters take requests from the upper layers and do
 115 all IO between the
 116 .Em SCSI
 117 bus and the system. The maximum size of a transfer is governed by the
 118 adapter. Most adapters can transfer 64KB in a single operation, however
 119 many can transfer larger amounts.
 120 .Sh TARGET MODE
 121 Some adapters support
 122 .Em target mode
 123 in which the system is capable of operating as a device, responding to
 124 operations initiated by another system. Target mode will be supported for
 125 some adapters, but is not yet complete for this version of the scsi system.
 126 .Sh DIAGNOSTICS
 127 When the kernel is compiled with option SCSIDEBUG, the SCIOCDEBUG ioctl
 128 can be used to enable various amounts of tracing information on any
 129 specific device. Devices not being traced will not produce trace information.
 130 The four bits that make up the debug level, each control certain types
 131 of debugging information.
 132 .Bl -tag -width "Bit 0"
 133 .It Dv Bit 0
 134 shows all scsi bus operations including scsi commands,
 135 error information and the first 48 bytes of any data transferred.
 136 .It Dv Bit 1
 137 shows routines called.
 138 .It Dv Bit 2
 139 shows information about what branches are taken and often some
 140 of the return values of functions.
 141 .It Dv Bit 3
 142 shows more detailed information including DMA scatter-gather logs.
 143 .El
 144 .Sh SEE ALSO
 145 .Xr ch 4 ,
 146 .Xr cd 4 ,
 147 .Xr sd 4 ,
 148 .Xr ss 4 ,
 149 .Xr st 4 ,
 150 .Xr su 4
 151 and
 152 .Xr uk 4
 153 .Sh HISTORY
 154 This
 155 .Nm
 156 system appeared in MACH 2.5 at TRW.