scm(D4sdi)

scm, scs -- Storage Device Interface (SDI) command structures

Synopsis

   #include <sys/scsi.h>

Description

The scm and scs structures are used by target drivers and the pass-through interface to send a command to a SDI device. The scs structure defines the layout for a group 6 (six-byte command length) command descriptor block (CDB); scm is a group 10 (ten-byte command length) CDB. Refer to the ANSI manual referenced in ``SCSI interface'' in HDK Technical Reference for more information about individual structure members.

The sm_pad0 member ensures that the sm_addr member does not cross a 32-bit word boundary.

Structure members

The members of the scm structure are:

   int       sm_pad0 : 16;   /* 16-bit pad */
   int       sm_op   : 8;    /* Opcode */
   int       sm_lun  : 3;    /* Logical unit number */
   int       sm_res1 : 5;    /* reserved field */
   unsigned  sm_addr;        /* Block address */
   int       sm_res2 : 8;    /* reserved field */
   int       sm_len  : 16;   /* Transfer length */
   int       sm_cont : 8;    /* Control byte */

The members of the scs structure are:

   int       ss_op   : 8;    /* Opcode */
   int       ss_lun  : 3;    /* Logical unit number */
   int       ss_addr : 21;   /* Block address */
   int       ss_len  : 8;    /* Transfer length */
   int       ss_cont : 8;    /* Control byte */

Usage

Because of the sm_pad0 member, you must add 2 to the address of the scm structure when specifying it in the scb structure.

Applicable hardware

All.

Version applicability

sdi: 2, 3, 4

References

``SDI pass-through interface'' in HDK Technical Reference