1 '\" te
2 .\" Copyright (c) 2007 by Sun Microsystems, Inc. All rights reserved.
3 .\" Copyright 2016 Joyent, Inc.
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 .TH USCSI 7I "Sep 23, 2016"
8 .SH NAME
9 uscsi \- user SCSI command interface
10 .SH SYNOPSIS
11 .LP
12 .nf
13 #include <sys/scsi/impl/uscsi.h>
14
15 \fB\fR\fBioctl\fR(\fBint\fR \fIfildes\fR, \fBint\fR \fIrequest\fR, \fBstruct uscsi_cmd *\fR\fIcmd\fR);
16 .fi
17
18 .SH DESCRIPTION
19 .LP
20 The \fBuscsi\fR command is very powerful and somewhat dangerous; therefore it
21 has some permission restrictions. See \fBWARNINGS\fR for more details.
22 .sp
23 .LP
24 Drivers supporting this \fBioctl\fR(2) provide a general interface allowing
25 user-level applications to cause individual \fBSCSI\fR commands to be directed
26 to a particular \fBSCSI\fR or \fBATAPI\fR device under control of that driver.
27 The \fBuscsi\fR command is supported by the \fBsd\fR driver for \fBSCSI\fR
28 disks and \fBATAPI\fR CD-ROM drives, and by the \fBst\fR driver for \fBSCSI\fR
29 tape drives. \fBuscsi\fR may also be supported by other device drivers; see the
30 specific device driver manual page for complete information.
31 .sp
32 .LP
33 Applications must not assume that all Solaris disk device drivers support the
34 \fBuscsi\fR ioctl command. The \fBSCSI\fR command may include a data transfer
35 to or from that device, if appropriate for that command. Upon completion of the
36 command, the user application can determine how many bytes were transferred and
37 the status returned by the device. Also, optionally, if the command returns a
38 Check Condition status, the driver will automatically issue a Request Sense
39 command and return the sense data along with the original status. See the
40 \fBUSCSI_RQENABLE\fR flag below for this Request Sense processing. The
41 \fBuscsi_cmd\fR structure is defined in \fB<sys/scsi/impl/uscsi.h>\fR and
42 includes the following members:
43 .sp
44 .in +2
45 .nf
46 int uscsi_flags; /* read, write, etc. see below */
47 short uscsi_status; /* resulting status */
48 short uscsi_timeout; /* Command Timeout */
49 caddr_t uscsi_cdb /* CDB to send to target */
50 caddr_t uscsi_bufaddr; /* i/o source/destination */
51 size_t uscsi_buflen; /* size of i/o to take place*/
52 size_t uscsi_resid; /* resid from i/o operation */
53 uchar_t uscsi_cdblen; /* # of valid CDB bytes */
54 uchar_t uscsi_rqlen; /* size of uscsi_rqbuf */
55 uchar_t uscsi_rqstatus; /* status of request sense cmd */
56 uchar_t uscsi_rqresid; /* resid of request sense cmd */
57 caddr_t uscsi_rqbuf; /* request sense buffer */
58 void *uscsi_reserved_5; /* Reserved for future use */
59 .fi
60 .in -2
61
62 .sp
63 .LP
64 The fields of the \fBuscsi_cmd\fR structure have the following meanings:
65 .sp
66 .ne 2
67 .na
68 \fB\fBuscsi_flags\fR\fR
69 .ad
70 .RS 20n
71 The \fBI/O\fR direction and other details of how to carry out the \fBSCSI\fR
72 command. Possible values are described below.
73 .RE
74
75 .sp
76 .ne 2
77 .na
78 \fB\fBuscsi_status\fR\fR
79 .ad
80 .RS 20n
81 The \fBSCSI\fR status byte returned by the device is returned in this field.
82 .RE
83
84 .sp
85 .ne 2
86 .na
87 \fB\fBuscsi_timeout\fR\fR
88 .ad
89 .RS 20n
90 Time in seconds to allow for completion of the command.
91 .RE
92
93 .sp
94 .ne 2
95 .na
96 \fB\fBuscsi_cdb\fR\fR
97 .ad
98 .RS 20n
99 A pointer to the \fBSCSI\fR CDB (command descriptor block) to be transferred to
100 the device in command phase.
101 .RE
102
103 .sp
104 .ne 2
105 .na
106 \fB\fBuscsi_bufaddr\fR\fR
107 .ad
108 .RS 20n
109 The user buffer containing the data to be read from or written to the device.
110 .RE
111
112 .sp
113 .ne 2
114 .na
115 \fB\fBuscsi_buflen\fR\fR
116 .ad
117 .RS 20n
118 The length of \fBuscsi_bufaddr\fR.
119 .RE
120
121 .sp
122 .ne 2
123 .na
124 \fB\fBuscsi_resid\fR\fR
125 .ad
126 .RS 20n
127 If a data transfer terminates without transferring the entire requested amount,
128 the remainder, or residue, is returned in this field.
129 .RE
130
131 .sp
132 .ne 2
133 .na
134 \fB\fBuscsi_cdblen\fR\fR
135 .ad
136 .RS 20n
137 The length of the \fBSCSI\fR CDB to be transferred to the device in command
138 phase.
139 .RE
140
141 .sp
142 .ne 2
143 .na
144 \fB\fBuscsi_rqlen\fR\fR
145 .ad
146 .RS 20n
147 The length of \fBuscsi_rqbuf\fR, the application's Request Sense buffer.
148 .RE
149
150 .sp
151 .ne 2
152 .na
153 \fB\fBuscsi_rqstatus\fR\fR
154 .ad
155 .RS 20n
156 The \fBSCSI\fR status byte returned for the Request Sense command executed
157 automatically by the driver in response to a Check Condition status return.
158 .RE
159
160 .sp
161 .ne 2
162 .na
163 \fB\fBuscsi_rqresid\fR\fR
164 .ad
165 .RS 20n
166 The residue, or untransferred data length, of the Request Sense data transfer
167 (the number of bytes, less than or equal to \fBuscsi_rqlen\fR, which were not
168 filled with sense data).
169 .RE
170
171 .sp
172 .ne 2
173 .na
174 \fB\fBuscsi_rqbuf\fR\fR
175 .ad
176 .RS 20n
177 Points to a buffer in application address space to which the results of an
178 automatic Request Sense command are written.
179 .RE
180
181 .sp
182 .ne 2
183 .na
184 \fB\fBuscsi_reserved_5\fR\fR
185 .ad
186 .RS 20n
187 Reserved for future use.
188 .RE
189
190 .sp
191 .LP
192 The \fBuscsi_flags\fR field defines the following:
193 .sp
194 .in +2
195 .nf
196 USCSI_WRITE /* send data to device */
197 USCSI_SILENT /* no error messages */
198 USCSI_DIAGNOSE /* fail if any error occurs */
199 USCSI_ISOLATE /* isolate from normal commands */
200 USCSI_READ /* get data from device */
201 USCSI_ASYNC /* set bus to asynchronous mode */
202 USCSI_SYNC /* return bus to sync mode if possible */
203 USCSI_RESET /* reset target */
204 USCSI_RESET_TARGET /* reset target */
205 USCSI_RESET_LUN /* reset logical unit */
206 USCSI_RESET_ALL /* reset all targets */
207 USCSI_RQENABLE /* enable request sense extensions */
208 USCSI_RENEGOT /* renegotiate wide/sync on next I/O */
209 .fi
210 .in -2
211
212 .sp
213 .LP
214 The \fBuscsi_flags\fR bits have the following interpretation:
215 .sp
216 .ne 2
217 .na
218 \fB\fBUSCSI_WRITE\fR\fR
219 .ad
220 .RS 22n
221 Data will be written from the initiator to the target.
222 .RE
223
224 .sp
225 .ne 2
226 .na
227 \fB\fBUSCSI_SILENT\fR\fR
228 .ad
229 .RS 22n
230 The driver should not print any console error messages or warnings regarding
231 failures associated with this \fBSCSI\fR command.
232 .RE
233
234 .sp
235 .ne 2
236 .na
237 \fB\fBUSCSI_DIAGNOSE\fR\fR
238 .ad
239 .RS 22n
240 The driver should not attempt any retries or other recovery mechanisms if this
241 \fBSCSI\fR command terminates abnormally in any way.
242 .RE
243
244 .sp
245 .ne 2
246 .na
247 \fB\fBUSCSI_ISOLATE\fR\fR
248 .ad
249 .RS 22n
250 This \fBSCSI\fR command should not be executed with other commands.
251 .RE
252
253 .sp
254 .ne 2
255 .na
256 \fB\fBUSCSI_READ\fR\fR
257 .ad
258 .RS 22n
259 Data will be read from the target to the initiator.
260 .RE
261
262 .sp
263 .ne 2
264 .na
265 \fB\fBUSCSI_ASYNC\fR\fR
266 .ad
267 .RS 22n
268 Set the \fBSCSI\fR bus to asynchronous mode before running this command.
269 .RE
270
271 .sp
272 .ne 2
273 .na
274 \fB\fBUSCSI_SYNC\fR\fR
275 .ad
276 .RS 22n
277 Set the \fBSCSI\fR bus to synchronous mode before running this command.
278 .RE
279
280 .sp
281 .ne 2
282 .na
283 \fB\fBUSCSI_RESET\fR\fR
284 .ad
285 .RS 22n
286 Send a \fBSCSI\fR bus device reset message to this target.
287 .RE
288
289 .sp
290 .ne 2
291 .na
292 \fB\fBUSCSI_RESET_TARGET\fR\fR
293 .ad
294 .RS 22n
295 Same as USCSI_RESET. Use this flag to request TARGET RESET. (USCSI_RESET is
296 maintained only for compatibility with old applications).
297 .RE
298
299 .sp
300 .ne 2
301 .na
302 \fB\fBUSCSI_RESET_LUN\fR\fR
303 .ad
304 .RS 22n
305 Send a \fBSCSI\fR logical unit reset message to this target.
306 .RE
307
308 .sp
309 .ne 2
310 .na
311 \fB\fBUSCSI_RESET_ALL\fR\fR
312 .ad
313 .RS 22n
314 USCSI_RESET_ALL, USCSI_RESET/USCSI_RESET_TARGET and USCSI_RESET_LUN are
315 mutually exclusive options and issuing them in any simultaneous combination
316 will result in implementation-dependent behavior
317 .sp
318 When a USCSI reset request is combined with other \fBSCSI\fR commands, the
319 following semantics take effect:
320 .sp
321 If the USCSI RESET flag is specified, the other fields (other than uscsi_flags)
322 in the uscsi_cmd are ignored. The uscsi_cdblen \fBmust\fR be set to zero.
323 .RE
324
325 .sp
326 .ne 2
327 .na
328 \fB\fBUSCSI_RQENABLE\fR\fR
329 .ad
330 .RS 22n
331 Enable Request Sense extensions. If the user application is prepared to receive
332 sense data, this bit must be set, the fields \fBuscsi_rqbuf\fR and
333 \fBuscsi_rqbuflen\fR must be non-zero, and the \fBuscsi_rqbuf\fR must point to
334 memory writable by the application.
335 .RE
336
337 .sp
338 .ne 2
339 .na
340 \fB\fBUSCSI_RENEGOT\fR\fR
341 .ad
342 .RS 22n
343 Tells USCSI to renegotiate wide mode and synchronous transfer speed before the
344 transmitted SCSI command is executed. This flag in effects tells the target
345 driver to pass the \fBFLAG_RENEGOTIATE_WIDE_SYNC\fR flag in the SCSI packet
346 before passing the command to an adapter driver for transport.
347 .sp
348 See the \fBscsi_pkt\fR(9S) flag \fBFLAG_RENEGOTIATE_WIDE_SYNC\fR for more
349 information.
350 .RE
351
352 The \fBuscsi_xfer_t\fR is a type definition that corresponds to a 64-bit
353 unsigned integer. It should be used for the \fBUSCSIMAXXFER\fR ioctls. This is
354 used for determining the maximum transfer size that can be performed in a single
355 \fBUSCSICMD\fR ioctl. If the SCSI request is larger than the specified size,
356 then it may not work, depending on the hardware platform.
357
358 .SH IOCTLS
359 .LP
360 The \fBioctl\fR supported by drivers providing the \fBuscsi\fR interface is:
361 .sp
362 .ne 2
363 .na
364 \fB\fBUSCSICMD\fR\fR
365 .ad
366 .RS 12n
367 The argument is a pointer to a \fBuscsi_cmd\fR structure. The \fBSCSI\fR device
368 addressed by that driver is selected, and given the \fBSCSI\fR command
369 addressed by \fBuscsi_cdb\fR. If this command requires a data phase, the
370 \fBuscsi_buflen\fR and \fBuscsi_bufaddr\fR fields must be set appropriately; if
371 data phase occurs, the \fBuscsi_resid\fR is returned as the number of bytes not
372 transferred. The status of the command, as returned by the device, is returned
373 in the \fBuscsi_status\fR field. If the command terminates with Check Condition
374 status, and Request Sense is enabled, the sense data itself is returned in
375 \fBuscsi_rqbuf\fR. The \fBuscsi_rqresid\fR provides the residue of the Request
376 Sense data transfer.
377 .RE
378
379 .sp
380 .ne 2
381 .na
382 .B USCSIMAXXFER
383 .ad
384 .RS 12n
385 The argument is a pointer to a \fBuscsi_xfer_t\fR value. The maximum transfer
386 size that can be used with the \fBUSCSICMD\fR ioctl for the current device will
387 be returned in the \fBuscsi_xfer_t\fR.
388 .sp
389 .LP
390 Not all devices which support the \fBUSCSICMD\fR ioctl also support the
391 \fBUSCSIMAXXFER\fR ioctl.
392 .RE
393
394 .SH ERRORS
395 .ne 2
396 .na
397 \fB\fBEINVAL\fR\fR
398 .ad
399 .RS 10n
400 A parameter has an incorrect, or unsupported, value.
401 .RE
402
403 .sp
404 .ne 2
405 .na
406 \fB\fBEIO\fR\fR
407 .ad
408 .RS 10n
409 An error occurred during the execution of the command.
410 .RE
411
412 .sp
413 .ne 2
414 .na
415 \fB\fBEPERM\fR\fR
416 .ad
417 .RS 10n
418 A process without root credentials tried to execute the \fBUSCSICMD\fR or
419 \fBUSCSIMAXXFER\fR ioctl.
420 .RE
421
422 .sp
423 .ne 2
424 .na
425 \fB\fBEFAULT\fR\fR
426 .ad
427 .RS 10n
428 The \fBuscsi_cmd\fR itself, the \fBuscsi_cdb\fR, the \fBuscsi_buf\fR, the
429 \fBuscsi_rqbuf\fR, or the \fBuscsi_xfer_t\fR point to an invalid address.
430 .RE
431
432 .SH ATTRIBUTES
433 .LP
434 See \fBattributes\fR(5) for descriptions of the following attributes:
435 .sp
436
437 .sp
438 .TS
439 box;
440 c | c
441 l | l .
442 ATTRIBUTE TYPE ATTRIBUTE VALUE
443 _
444 Interface Stability Committed
445 .TE
446
447 .SH SEE ALSO
448 .LP
449 \fBioctl\fR(2), \fBattributes\fR(5), \fBsd\fR(7D), \fBst\fR(7D)
450 .sp
451 .LP
452 \fIANSI Small Computer System Interface-2 (SCSI-2)\fR
453 .SH WARNINGS
454 .LP
455 The \fBuscsi\fR command is very powerful, but somewhat dangerous, and so its
456 use is restricted to processes running as root, regardless of the file
457 permissions on the device node. The device driver code expects to own the
458 device state, and \fBuscsi\fR commands can change the state of the device and
459 confuse the device driver. It is best to use \fBuscsi\fR commands only with no
460 side effects, and avoid commands such as Mode Select, as they may cause damage
461 to data stored on the drive or system panics. Also, as the commands are not
462 checked in any way by the device driver, any block may be overwritten, and the
463 block numbers are absolute block numbers on the drive regardless of which slice
464 number is used to send the command.
465 .sp
466 .LP
467 The \fBuscsi\fR interface is not recommended for very large data transfers
468 (typically more than 16MB). If the requested transfer size exceeds the maximum
469 transfer size of the DMA engine, it will not be broken up into multiple
470 transfers and DMA errors may result. The \fBUSCSIMAXXFER\fR ioctl can be used
471 to determine the maximum transfer size.
472 .sp
473 .LP
474 The \fBUSCSICMD\fR ioctl associates a \fBstruct uscsi_cmd\fR with a device by
475 using an open file descriptor to the device. Other APIs might provide the same
476 \fBstruct uscsi_cmd\fR programming interface, but perform device association in
477 some other manner.
|
1 .\" Copyright (c) 2007 by Sun Microsystems, Inc. All rights reserved.
2 .\" Copyright 2017 Joyent, Inc.
3 .\" The contents of this file are subject to the terms of the
4 .\" Common Development and Distribution License (the "License").
5 .\" You may not use this file except in compliance with the License.
6 .\"
7 .\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
8 .\" or http://www.opensolaris.org/os/licensing.
9 .\" See the License for the specific language governing permissions
10 .\" and limitations under the License.
11 .\"
12 .\" When distributing Covered Code, include this CDDL HEADER in each
13 .\" file and include the License file at usr/src/OPENSOLARIS.LICENSE.
14 .\" If applicable, add the following below this CDDL HEADER, with the
15 .\" fields enclosed by brackets "[]" replaced with your own identifying
16 .\" information: Portions Copyright [yyyy] [name of copyright owner]
17 .Dd October 23, 2017
18 .Dt USCSI 7I
19 .Os
20 .Sh NAME
21 .Nm uscsi
22 .Nd user SCSI command interface
23 .Sh SYNOPSIS
24 .In sys/scsi/impl/uscsi.h
25 .Fo ioctl
26 .Fa "int filedes"
27 .Fa "int request"
28 .Fa "struct uscsi_cmd *cmd"
29 .Fc
30 .Sh DESCRIPTION
31 The
32 .Nm
33 command is very powerful and somewhat dangerous; therefore it
34 has some permission restrictions.
35 See
36 .Sx WARNINGS
37 for more details.
38 .Pp
39 Drivers supporting this
40 .Xr ioctl 2
41 provide a general interface allowing user-level applications to cause individual
42 .Sy SCSI
43 commands to be directed to a particular
44 .Sy SCSI
45 or
46 .Sy ATAPI
47 device under control of that driver.
48 The
49 .Nm
50 command is supported by the
51 .Xr sd 7D
52 driver for
53 .Sy SCSI
54 disks and
55 .Sy ATAPI
56 CD-ROM drives, and by the
57 .Xr st 7D
58 driver for
59 .Sy SCSI
60 tape drives.
61 .Nm
62 may also be supported by other device drivers; see the
63 specific device driver manual page for complete information.
64 .Pp
65 Applications must not assume that all Solaris disk device drivers support the
66 .Nm
67 ioctl command.
68 The
69 .Sy SCSI
70 command may include a data transfer
71 to or from that device, if appropriate for that command.
72 Upon completion of the command, the user application can determine how many
73 bytes were transferred and the status returned by the device.
74 Also, optionally, if the command returns a
75 Check Condition status, the driver will automatically issue a Request Sense
76 command and return the sense data along with the original status.
77 See the
78 .Sy USCSI_RQENABLE
79 flag below for this Request Sense processing.
80 The
81 .Vt uscsi_cmd
82 structure is defined in
83 .In sys/scsi/impl/uscsi.h
84 and includes the following members:
85 .Bd -literal -offset 2n
86 int uscsi_flags; /* read, write, etc. see below */
87 short uscsi_status; /* resulting status */
88 short uscsi_timeout; /* Command Timeout */
89 caddr_t uscsi_cdb /* CDB to send to target */
90 caddr_t uscsi_bufaddr; /* i/o source/destination */
91 size_t uscsi_buflen; /* size of i/o to take place*/
92 size_t uscsi_resid; /* resid from i/o operation */
93 uchar_t uscsi_cdblen; /* # of valid CDB bytes */
94 uchar_t uscsi_rqlen; /* size of uscsi_rqbuf */
95 uchar_t uscsi_rqstatus; /* status of request sense cmd */
96 uchar_t uscsi_rqresid; /* resid of request sense cmd */
97 caddr_t uscsi_rqbuf; /* request sense buffer */
98 void *uscsi_reserved_5; /* Reserved for future use */
99 .Ed
100 .Pp
101 The fields of the
102 .Vt uscsi_cmd
103 structure have the following meanings:
104 .Bl -tag -width uscsi_reserved_5
105 .It Sy uscsi_flags
106 The
107 .Sy I/O
108 direction and other details of how to carry out the
109 .Sy SCSI
110 command.
111 Possible values are described below.
112 .It Fa uscsi_status
113 The
114 .Sy SCSI
115 status byte returned by the device is returned in this field.
116 .It Fa uscsi_timeout
117 Time in seconds to allow for completion of the command.
118 .It Fa uscsi_cdb
119 A pointer to the
120 .Sy SCSI
121 CDB (command descriptor block) to be transferred to the device in command phase.
122 .It Fa uscsi_bufaddr
123 The user buffer containing the data to be read from or written to the device.
124 .It Sy uscsi_buflen
125 The length of
126 .Fa uscsi_bufaddr .
127 .It Fa uscsi_resid
128 If a data transfer terminates without transferring the entire requested amount,
129 the remainder, or residue, is returned in this field.
130 .It Fa uscsi_cdblen
131 The length of the
132 .Sy SCSI
133 CDB to be transferred to the device in command phase.
134 .It Fa uscsi_rqlen
135 The length of
136 .Fa uscsi_rqbuf ,
137 the application's Request Sense buffer.
138 .It Fa uscsi_rqstatus
139 The
140 .Sy SCSI
141 status byte returned for the Request Sense command executed
142 automatically by the driver in response to a Check Condition status return.
143 .It Fa uscsi_rqresid
144 The residue, or untransferred data length, of the Request Sense data transfer
145 (the number of bytes, less than or equal to
146 .Fa uscsi_rqlen ,
147 which were not filled with sense data).
148 .It Fa uscsi_rqbuf
149 Points to a buffer in application address space to which the results of an
150 automatic Request Sense command are written.
151 .It Fa uscsi_reserved_5
152 Reserved for future use.
153 .El
154 .Pp
155 The
156 .Fa uscsi_flags
157 field defines the following:
158 .Bd -literal -offset 2n
159 USCSI_WRITE /* send data to device */
160 USCSI_SILENT /* no error messages */
161 USCSI_DIAGNOSE /* fail if any error occurs */
162 USCSI_ISOLATE /* isolate from normal commands */
163 USCSI_READ /* get data from device */
164 USCSI_ASYNC /* set bus to asynchronous mode */
165 USCSI_SYNC /* return bus to sync mode if possible */
166 USCSI_RESET /* reset target */
167 USCSI_RESET_TARGET /* reset target */
168 USCSI_RESET_LUN /* reset logical unit */
169 USCSI_RESET_ALL /* reset all targets */
170 USCSI_RQENABLE /* enable request sense extensions */
171 USCSI_RENEGOT /* renegotiate wide/sync on next I/O */
172 .Ed
173 .Pp
174 The
175 .Fa uscsi_flags
176 bits have the following interpretation:
177 .Bl -tag -width USCSI_RESET_TARGET
178 .It Dv USCSI_WRITE
179 Data will be written from the initiator to the target.
180 .It Dv USCSI_SILENT
181 The driver should not print any console error messages or warnings regarding
182 failures associated with this
183 .Sy SCSI
184 command.
185 .It Dv USCSI_DIAGNOSE
186 The driver should not attempt any retries or other recovery mechanisms if this
187 .Sy SCSI
188 command terminates abnormally in any way.
189 .It Dv USCSI_ISOLATE
190 This
191 .Sy SCSI
192 command should not be executed with other commands.
193 .It Dv USCSI_READ
194 Data will be read from the target to the initiator.
195 .It Dv USCSI_ASYNC
196 Set the
197 .Sy SCSI
198 bus to asynchronous mode before running this command.
199 .It Dv USCSI_SYNC
200 Set the
201 .Sy SCSI
202 bus to synchronous mode before running this command.
203 .It Dv USCSI_RESET
204 Send a
205 .Sy SCSI
206 bus device reset message to this target.
207 .It Dv USCSI_RESET_TARGET
208 Same as USCSI_RESET.
209 Use this flag to request TARGET RESET.
210 .Po
211 .Dv USCSI_RESET
212 is maintained only for compatibility with old applications
213 .Pc .
214 .It Dv USCSI_RESET_LUN
215 Send a
216 .Sy SCSI
217 logical unit reset message to this target.
218 .It Dv USCSI_RESET_ALL
219 .Dv USCSI_RESET_ALL ,
220 .Dv USCSI_RESET/USCSI_RESET_TARGET ,
221 and
222 .Dv USCSI_RESET_LUN
223 are
224 mutually exclusive options and issuing them in any simultaneous combination
225 will result in implementation-dependent behavior
226 When a USCSI reset request is combined with other
227 .Sy SCSI
228 commands, the following semantics take effect:
229 If the
230 .Dv USCSI RESET
231 flag is specified, the other fields (other than
232 .Fa uscsi_flags )
233 in the
234 .Vt uscsi_cmd
235 are ignored.
236 The
237 .Fa uscsi_cdblen
238 field
239 .Em must
240 be set to zero.
241 .It Dv USCSI_RQENABLE
242 Enable Request Sense extensions.
243 If the user application is prepared to receive
244 sense data, this bit must be set, the fields
245 .Fa uscsi_rqbuf
246 and
247 .Fa uscsi_rqbuflen
248 must be non-zero, and the
249 .Fa uscsi_rqbuf
250 must point to memory writable by the application.
251 .It Dv USCSI_RENEGOT
252 Tells USCSI to renegotiate wide mode and synchronous transfer speed before the
253 transmitted SCSI command is executed.
254 This flag in effects tells the target driver to pass the
255 .Dv FLAG_RENEGOTIATE_WIDE_SYNC
256 flag in the SCSI packet
257 before passing the command to an adapter driver for transport.
258 See the
259 .Xr scsi_pkt 9S
260 flag
261 .Dv FLAG_RENEGOTIATE_WIDE_SYNC
262 for more information.
263 .El
264 .Pp
265 The
266 .Vt uscsi_xfer_t
267 is a type definition that corresponds to a 64-bit unsigned integer.
268 It should be used for the
269 .Dv USCSIMAXXFER
270 ioctls.
271 This is
272 used for determining the maximum transfer size that can be performed in a single
273 .Dv USCSICMD
274 ioctl.
275 If the SCSI request is larger than the specified size,
276 then it may not work, depending on the hardware platform.
277 .Sh IOCTLS
278 The
279 .Fn ioctl
280 supported by drivers providing the
281 .Nm
282 interface is:
283 .Bl -tag -width USCSIMAXXFER
284 .It Dv USCSICMD
285 The argument is a pointer to a
286 .Vt uscsi_cmd
287 structure.
288 The
289 .Sy SCSI
290 device addressed by that driver is selected, and given the
291 .Sy SCSI
292 command addressed by
293 .Fa uscsi_cdb .
294 If this command requires a data phase, the
295 .Fa uscsi_buflen
296 and
297 .Fa uscsi_bufaddr
298 fields must be set appropriately; if data phase occurs, the
299 .Fa uscsi_resid
300 is returned as the number of bytes not transferred.
301 The status of the command, as returned by the device, is returned in the
302 .Fa uscsi_status
303 field.
304 If the command terminates with Check Condition
305 status, and Request Sense is enabled, the sense data itself is returned in
306 .Fa uscsi_rqbuf .
307 The
308 .Fa uscsi_rqresid
309 provides the residue of the Request Sense data transfer.
310 .It Dv USCSIMAXXFER
311 The argument is a pointer to a
312 .Vt uscsi_xfer_t
313 value.
314 The maximum transfer size that can be used with the
315 .Dv USCSICMD
316 ioctl for the current device will be returned in the
317 .Vt uscsi_xfer_t .
318 .Pp
319 Not all devices which support the
320 .Dv USCSICMD
321 ioctl also support the
322 .Dv USCSIMAXXFER
323 ioctl.
324 .El
325 .Sh ERRORS
326 .Bl -tag -width EINVAL
327 .It Er EINVAL
328 A parameter has an incorrect, or unsupported, value.
329 .It Er EIO
330 An error occurred during the execution of the command.
331 .It Er EPERM
332 A process without root credentials tried to execute the
333 .Dv USCSICMD
334 or
335 .Dv USCSIMAXXFER
336 ioctl.
337 .It Er EFAULT
338 The
339 .Vt uscsi_cmd
340 itself, the
341 .Fa uscsi_cdb ,
342 the
343 .Fa uscsi_buf ,
344 the
345 .Fa uscsi_rqbuf ,
346 or the
347 .Vt uscsi_xfer_t
348 point to an invalid address.
349 .El
350 .Sh STABILITY
351 Committed
352 .Sh SEE ALSO
353 .Xr ioctl 2 ,
354 .Xr attributes 5 ,
355 .Xr sd 7D ,
356 .Xr st 7D
357 .Rs
358 .%T ANSI Small Computer System Interface-2 (SCSI-2)
359 .Re
360 .Sh WARNINGS
361 The
362 .Nm
363 command is very powerful, but somewhat dangerous, and so its
364 use is restricted to processes running as root, regardless of the file
365 permissions on the device node.
366 The device driver code expects to own the device state, and
367 .Nm
368 commands can change the state of the device and confuse the device driver.
369 It is best to use
370 .Nm
371 commands only with no side effects, and avoid commands such as Mode Select, as
372 they may cause damage to data stored on the drive or system panics.
373 Also, as the commands are not checked in any way by the device driver, any block
374 may be overwritten, and the block numbers are absolute block numbers on the
375 drive regardless of which slice number is used to send the command.
376 .Pp
377 The
378 .Nm
379 interface is not recommended for very large data transfers
380 (typically more than 16MB).
381 If the requested transfer size exceeds the maximum transfer size of the DMA
382 engine, it will not be broken up into multiple transfers and DMA errors may
383 result.
384 The
385 .Dv USCSIMAXXFER
386 ioctl can be used to determine the maximum transfer size.
387 .Pp
388 The
389 .Dv USCSICMD
390 ioctl associates a
391 .Vt struct uscsi_cmd
392 with a device by using an open file descriptor to the device.
393 Other APIs might provide the same
394 .Vt struct uscsi_cmd
395 programming interface, but perform device association in some other manner.
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