1.\" Copyright (c) 2000, Sun Microsystems, Inc., All Rights Reserved 2.\" Copyright (c) 2017, Joyent, Inc. 3.\" Copyright 2022 Oxide Computer Company 4.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). You may not use this file except in compliance with the License. 5.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing. See the License for the specific language governing permissions and limitations under the License. 6.\" When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] 7.Dd January 29, 2022 8.Dt SCSI_ADDRESS 9S 9.Os 10.Sh NAME 11.Nm scsi_address 12.Nd SCSI address structure 13.Sh SYNOPSIS 14.In sys/scsi/scsi.h 15.Sh INTERFACE LEVEL 16illumos architecture specific (illumos DDI) 17.Sh DESCRIPTION 18A 19.Vt scsi_address 20structure defines the addressing components for a SCSI target device. 21The address of the target device is separated into two components: 22target number and logical unit number. 23The two addressing components are used to uniquely identify any type of 24SCSI device; however, most devices can be addressed with the target 25component of the address. 26.Pp 27In the case where only the target component is used to address the device, the 28logical unit should be set to 29.Sy 0 . 30If the SCSI target device supports logical units, then the HBA must 31interpret the logical units field of the data structure. 32.Pp 33The 34.Fa pkt_address 35member of a 36.Xr scsi_pkt 9S 37is initialized by 38.Xr scsi_init_pkt 9F . 39.Ss Complex Addressing 40HBA drivers may set the flag 41.Dv SCSI_HBA_ADDR_COMPLEX 42in the 43.Fa hba_flags 44argument to 45.Xr scsi_hba_attach_setup 9F . 46When the flag is set, the way this structure is used changes. 47While the 48.Fa a_hba_tran 49member is still accessible for accessing the 50.Xr scsi_hba_tran 9S 51structure, the nature of addressing changes. 52.Pp 53When using complex addressing, a particular device is addressed through a unit 54address which takes the shape of a string. 55When using complex addressing, the target and lun fields are inaccessible and 56instead a device driver can obtain the 57.Xr scsi_device 9S 58structure that this address corresponds to. 59In the complex addressing world, this is generally a direct mapping. 60To obtain this structure, a driver would call the 61.Xr scsi_address_device 9F 62function. 63.Pp 64With the 65.Xr scsi_device 9S 66structure, the device driver can then get to the device-specific private data 67through the 68.Xr scsi_device_hba_private_get 9F 69function. 70.Sh STRUCTURE MEMBERS 71.Bd -literal 72scsi_hba_tran_t *a_hba_tran; /* Transport vectors for the SCSI bus */ 73ushort_t a_target; /* SCSI target id */ 74uchar_t a_lun; /* SCSI logical unit */ 75.Ed 76.Pp 77.Fa a_hba_tran 78is a pointer to the controlling HBA's transport vector structure. 79The SCSA interface uses this field to pass any transport requests from the SCSI 80target device drivers to the HBA driver. 81This member is accessible regardless of whether the device driver uses complex 82addressing or not. 83.Pp 84.Fa a_target 85is the target component of the SCSI address. 86This member is not accessible when the device driver uses complex addressing. 87.Pp 88.Fa a_lun 89is the logical unit component of the SCSI address. 90The logical unit is used to further distinguish a SCSI target device that 91supports multiple logical units from one that does not. 92This member is not accessible when the device driver uses complex addressing. 93.Sh SEE ALSO 94.Xr scsi_address_device 9F , 95.Xr scsi_device_hba_private_get 9F , 96.Xr scsi_hba_attach_setup 9F , 97.Xr scsi_init_pkt 9F , 98.Xr scsi_device 9S , 99.Xr scsi_hba_tran 9S , 100.Xr scsi_pkt 9S 101.Pp 102.Rs 103.%T Writing Device Drivers 104.Re 105