SCSI_ADDRESS(9S) Data Structures for Drivers SCSI_ADDRESS(9S)

SCSI address structure

#include <sys/scsi/scsi.h>

illumos architecture specific (illumos DDI)

A scsi_address structure defines the addressing components for a 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 SCSI device; however, most devices can be addressed with the target component of the address.

In the case where only the target component is used to address the device, the logical unit should be set to 0. If the SCSI target device supports logical units, then the HBA must interpret the logical units field of the data structure.

The pkt_address member of a scsi_pkt(9S) is initialized by scsi_init_pkt(9F).

Drivers may set the flag SCSI_HBA_ADDR_COMPLEX in the hba_flags argument to 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 scsi_hba_tran(9S) structure, the address structure can store any arbitrary pointer through the scsi_device_hba_private_get(9F) and scsi_device_hba_private_set(9F) functions.

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 */

a_hba_tran is a pointer to the controlling HBA 's transport vector structure. The SCSA interface uses this field to pass any transport requests from the SCSI target device drivers to the HBA driver.

a_target is the target component of the SCSI address

a_lun is the logical unit component of the SCSI address. The logical unit is used to further distinguish a SCSI target device that supports multiple logical units from one that does not.

If the flag, SCSI_HBA_ADDR_COMPLEX was set, then the driver must not dereference any of these fields, the structure contents will have changed and should be considered opaque.

scsi_device_hba_private_get(9F), scsi_device_hba_private_set(9F), scsi_hba_attach_setup(9F), scsi_init_pkt(9F), scsi_hba_tran(9S), scsi_pkt(9S)

Writing Device Drivers.

April 23, 2017 OmniOS