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.Dd Apr 23, 2017
.Dt SCSI_ADDRESS 9S
.Os
.Sh NAME
.Nm scsi_address
.Nd SCSI address structure
.Sh SYNOPSIS
.In sys/scsi/scsi.h
.Sh INTERFACE LEVEL
illumos architecture specific (illumos DDI)
.Sh DESCRIPTION
A
.Vt scsi_address
structure defines the addressing components for a
.Sy SCSI
target device.
The address of the target device is separated into two components:
target number and logical unit number.
The two addressing components are used to uniquely identify any type of
.Sy SCSI
device; however, most devices can be addressed with the target component of the
address.
.Pp
In the case where only the target component is used to address the device, the
logical unit should be set to
.Sy 0 . If the
.Sy SCSI
target device supports logical units, then the HBA must interpret the
logical units field of the data structure.
.Pp
The
.Sy pkt_address
member of a
.Xr scsi_pkt 9S
is initialized by
.Xr scsi_init_pkt 9F .
.Ss Complex Addressing
Drivers may set the flag
.Dv SCSI_HBA_ADDR_COMPLEX
in the
.Fa hba_flags
argument to
.Xr scsi_hba_attach_setup 9F .
When the flag is set, this structure must be treated as opaque.
Instead of storing a traditional target and LUN, the address is treated
as the string form of a unit address.
In addition, rather than storing a pointer to the
.Xr scsi_hba_tran 9S
structure, the address structure can store any arbitrary pointer through
the
.Xr scsi_device_hba_private_get 9F
and
.Xr scsi_device_hba_private_set 9F
functions.
.Sh STRUCTURE MEMBERS
.Bd -literal
scsi_hba_tran_t   *a_hba_tran;  /* Transport vectors for the SCSI bus */
ushort_t          a_target;     /* SCSI target id */
uchar_t           a_lun;        /* SCSI logical unit */
.Ed
.Pp
.Fa a_hba_tran
is a pointer to the controlling
.Sy HBA 's
transport vector
structure.
The
.Sy SCSA
interface uses this field to pass any transport
requests from the
.Sy SCSI
target device drivers to the
.Sy HBA
driver.
.Pp
.Fa a_target
is the target component of the
.Sy SCSI
address
.Pp
.Fa a_lun
is the logical unit component of the
.Sy SCSI
address.
The logical unit is used to further distinguish a
.Sy SCSI
target device that
supports multiple logical units from one that does not.
.Pp
If the flag,
.Dv SCSI_HBA_ADDR_COMPLEX
was set, then the driver
.Em must not
dereference any of these fields, the structure contents will have
changed and should be considered opaque.
.Sh SEE ALSO
.Xr scsi_device_hba_private_get 9F ,
.Xr scsi_device_hba_private_set 9F ,
.Xr scsi_hba_attach_setup 9F ,
.Xr scsi_init_pkt 9F ,
.Xr scsi_hba_tran 9S ,
.Xr scsi_pkt 9S
.Pp
.Rs
.%T Writing Device Drivers
.Re