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1 '\" te
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6 .TH SCSI_INIT_PKT 9F "Jan 16, 2006"
7 .SH NAME
8 scsi_init_pkt \- prepare a complete SCSI packet
9 .SH SYNOPSIS
10 .LP
11 .nf
12 #include <sys/scsi/scsi.h>
16 \fBstruct scsi_pkt *\fR\fBscsi_init_pkt\fR(\fBstruct scsi_address *\fR\fIap\fR,
17 \fBstruct scsi_pkt *\fR\fIpktp\fR, \fBstruct buf *\fR\fIbp\fR, \fBint\fR \fIcmdlen\fR, \fBint\fR \fIstatuslen\fR,
18 \fBint\fR \fIprivatelen\fR, \fBint\fR \fIflags\fR, \fBint\fR \fB(*\fRcallback\fB)(caddr_t)\fR, \fBcaddr_t\fR \fIarg\fR);
19 .fi
21 .SH INTERFACE LEVEL
22 .sp
23 .LP
24 Solaris DDI specific (Solaris DDI).
25 .SH PARAMETERS
26 .sp
27 .ne 2
28 .na
29 \fB\fIap\fR\fR
30 .ad
31 .sp .6
32 .RS 4n
33 Pointer to a \fBscsi_address\fR(9S) structure.
34 .RE
36 .sp
37 .ne 2
38 .na
39 \fB\fIpktp\fR\fR
40 .ad
41 .sp .6
42 .RS 4n
43 A pointer to a \fBscsi_pkt\fR(9S) structure.
44 .RE
46 .sp
47 .ne 2
48 .na
49 \fB\fIbp\fR\fR
50 .ad
51 .sp .6
52 .RS 4n
53 Pointer to a \fBbuf\fR(9S) structure.
54 .RE
56 .sp
57 .ne 2
58 .na
59 \fB\fIcmdlen\fR\fR
60 .ad
61 .sp .6
62 .RS 4n
63 The required length for the \fBSCSI \fRcommand descriptor block (\fBCDB\fR) in
64 bytes.
65 .RE
67 .sp
68 .ne 2
69 .na
70 \fB\fIstatuslen\fR\fR
71 .ad
72 .sp .6
73 .RS 4n
74 The required length for the \fBSCSI \fRstatus completion block (\fBSCB\fR) in
75 bytes. Valid values are:
76 .sp
77 .ne 2
78 .na
79 \fB\fB0\fR\fR
80 .ad
81 .sp .6
82 .RS 4n
83 No status back.
84 .RE
86 .sp
87 .ne 2
88 .na
89 \fB\fB1\fR\fR
90 .ad
91 .sp .6
92 .RS 4n
93 Return SCSI status byte.
94 .RE
96 .sp
97 .ne 2
98 .na
99 \fB\fBsizeof(scsi_arq_status)\fR\fR
100 .ad
101 .sp .6
102 .RS 4n
103 Return status information in a \fBscsi_arq_status\fR structure. This will
104 include up to 20 bytes of sense data. Please refer to \fBscsi_arq_status\fR(9S)
105 for more information.
106 .sp
107 For extra sense packets (\fBPKT_XARQ\fR flag asserted), set \fIstatuslen\fR to
108 be a greater number like, (\fIN\fR + \fBsizeof(struct scsi_arq_status)\fR)
109 where \fIN\fR is the number of extra bytes beyond the default 20. For example,
110 \fIN\fR=1 requests 21 bytes of sense, \fIN\fR=235 asks for 255 bytes.
111 .RE
113 .RE
115 .sp
116 .ne 2
117 .na
118 \fB\fIprivatelen\fR\fR
119 .ad
120 .sp .6
121 .RS 4n
122 The required length for the \fIpkt_private\fR area.
123 .RE
125 .sp
126 .ne 2
127 .na
128 \fB\fIflags\fR\fR
129 .ad
130 .sp .6
131 .RS 4n
132 Flags modifier.
133 .RE
135 .sp
136 .ne 2
137 .na
138 \fB\fIcallback\fR\fR
139 .ad
140 .sp .6
141 .RS 4n
142 A pointer to a callback function, \fBNULL_FUNC\fR, or \fBSLEEP_FUNC\fR.
143 .RE
145 .sp
146 .ne 2
147 .na
148 \fB\fIarg\fR\fR
149 .ad
150 .sp .6
151 .RS 4n
152 The \fIcallback\fR function argument.
153 .RE
155 .SH DESCRIPTION
156 .sp
157 .LP
158 Target drivers use \fBscsi_init_pkt()\fR to request the transport layer to
159 allocate and initialize a packet for a \fBSCSI\fR command which possibly
160 includes a data transfer. If \fIpktp\fR is \fINULL,\fR a new \fBscsi_pkt\fR(9S)
161 is allocated using the \fBHBA\fR driver's packet allocator. The \fIbp\fR is a
162 pointer to a \fBbuf\fR(9S) structure. If \fIbp\fR is non-\fINULL\fR and
163 contains a valid byte count, the \fBbuf\fR(9S) structure is also set up for
164 \fBDMA \fRtransfer using the \fBHBA\fR driver \fBDMA\fR resources allocator.
165 When \fIbp\fR is allocated by \fBscsi_alloc_consistent_buf\fR(9F), the
166 \fBPKT_CONSISTENT\fR bit must be set in the \fIflags\fR argument to ensure
167 proper operation. If \fIprivatelen\fR is non-zero then additional space is
168 allocated for the \fIpkt_private\fR area of the \fBscsi_pkt\fR(9S). On return
169 \fIpkt_private\fR points to this additional space. Otherwise \fIpkt_private\fR
170 is a pointer that is typically used to store the \fIbp\fR during execution of
171 the command. In this case \fIpkt_private\fR is \fINULL\fR on return.
172 .sp
173 .LP
174 The \fIflags\fR argument is a set of bit flags. Possible bits include:
175 .sp
176 .ne 2
177 .na
178 \fB\fBPKT_CONSISTENT\fR\fR
179 .ad
180 .sp .6
181 .RS 4n
182 This must be set if the \fBDMA\fR buffer was allocated using
183 \fBscsi_alloc_consistent_buf\fR(9F). In this case, the \fBHBA\fR driver will
184 guarantee that the data transfer is properly synchronized before performing the
185 target driver's command completion callback.
186 .RE
188 .sp
189 .ne 2
190 .na
191 \fB\fBPKT_DMA_PARTIAL\fR\fR
192 .ad
193 .sp .6
194 .RS 4n
195 This may be set if the driver can accept a partial \fBDMA\fR mapping. If set,
196 \fBscsi_init_pkt()\fR will allocate \fBDMA\fR resources with the
197 \fBDDI_DMA_PARTIAL\fR bit set in the \fBdmar_flag\fR element of the
198 \fBddi_dma_req\fR(9S) structure. The \fBpkt_resid\fR field of the
199 \fBscsi_pkt\fR(9S) structure may be returned with a non-zero value, which
200 indicates the number of bytes for which \fBscsi_init_pkt()\fR was unable to
201 allocate DMA resources. In this case, a subsequent call to
202 \fBscsi_init_pkt()\fR may be made for the same \fIpktp\fR and \fIbp\fR to
203 adjust the DMA resources to the next portion of the transfer. This sequence
204 should be repeated until the \fBpkt_resid\fR field is returned with a zero
205 value, which indicates that with transport of this final portion the entire
206 original request will have been satisfied.
207 .RE
209 .sp
210 .ne 2
211 .na
212 \fB\fBPKT_XARQ\fR\fR
213 .ad
214 .sp .6
215 .RS 4n
216 Setting this flag requests that the \fBHBA\fR return extra sense data for this
217 \fBscsi_pkt\fR(9S). The default auto request sense mechanism returns up to 20
218 bytes. More than 20 bytes of sense data can be requested by setting this flag
219 and setting the \fIstatuslen\fR correctly. Set the \fIstatuslen\fR to be the
220 \fBsizeof(struct scsi_arq_status)\fR plus the number of sense bytes needed
221 beyond 20. For example, set statuslen to be \fB(sizeof(struct scsi_arq_status)
222 + 5)\fR for 25 bytes of sense.
223 .RE
225 .sp
226 .LP
227 When calling \fBscsi_init_pkt()\fR to move already-allocated \fBDMA\fR
228 resources, the \fIcmdlen\fR, \fIstatuslen\fR, and \fIprivatelen\fR fields are
229 ignored.
230 .sp
231 .LP
232 The last argument \fIarg\fR is supplied to the \fIcallback\fR function when it
233 is invoked.
234 .sp
235 .LP
236 \fIcallback\fR indicates what the allocator routines should do when resources
237 are not available:
238 .sp
239 .ne 2
240 .na
241 \fB\fBNULL_FUNC\fR\fR
242 .ad
243 .RS 16n
244 Do not wait for resources. Return a \fINULL\fR pointer.
245 .RE
247 .sp
248 .ne 2
249 .na
250 \fB\fBSLEEP_FUNC\fR\fR
251 .ad
252 .RS 16n
253 Wait indefinitely for resources.
254 .RE
256 .sp
257 .ne 2
258 .na
259 \fBOther Values\fR
260 .ad
261 .RS 16n
262 \fIcallback\fR points to a function which is called when resources may have
263 become available. \fIcallback\fR must return either \fB0\fR (indicating that it
264 attempted to allocate resources but again failed to do so), in which case it is
265 put back on a list to be called again later, or \fB1\fR indicating either
266 success in allocating resources or indicating that it no longer cares for a
267 retry.
268 .RE
270 .sp
271 .LP
272 When allocating \fBDMA\fR resources, \fBscsi_init_pkt()\fR returns the
273 \fBscsi_pkt\fR field \fBpkt_resid\fR as the number of residual bytes for which
274 the system was unable to allocate \fBDMA\fR resources. A \fBpkt_resid\fR of
275 \fB0\fR means that all necessary \fBDMA\fR resources were allocated.
276 .SH RETURN VALUES
277 .sp
278 .LP
279 The \fBscsi_init_pkt()\fR function returns \fINULL\fR if the packet or
280 \fBDMA\fR resources could not be allocated. Otherwise, it returns a pointer to
281 an initialized \fBscsi_pkt\fR(9S). If \fIpktp\fR was not \fINULL\fR the return
282 value will be \fIpktp\fR on successful initialization of the packet.
283 .SH CONTEXT
284 .sp
285 .LP
286 If \fIcallback\fR is \fBSLEEP_FUNC\fR, then this routine can be called only
287 from user-level code. Otherwise, it can be called from user, interrupt, or
288 kernel context. The \fIcallback\fR function may not block or call routines that
289 block.
290 .SH EXAMPLES
291 .LP
292 \fBExample 1 \fRAllocating a Packet Without \fBDMA\fR Resources Attached
293 .sp
294 .LP
295 To allocate a packet without \fBDMA\fR resources attached, use:
297 .sp
298 .in +2
299 .nf
300 pkt = scsi_init_pkt(&devp->sd_address, NULL, NULL, CDB_GROUP1,
301 1, sizeof (struct my_pkt_private *), 0,
302 sd_runout, sd_unit);
303 .fi
304 .in -2
306 .LP
307 \fBExample 2 \fRAllocating a Packet With \fBDMA\fR Resources Attached
308 .sp
309 .LP
310 To allocate a packet with \fBDMA\fR resources attached use:
312 .sp
313 .in +2
314 .nf
315 pkt = scsi_init_pkt(&devp->sd_address, NULL, bp, CDB_GROUP1,
316 sizeof(struct scsi_arq_status), 0, 0, NULL_FUNC, NULL);
317 .fi
318 .in -2
320 .LP
321 \fBExample 3 \fRAttaching \fBDMA\fR Resources to a Preallocated Packet
322 .sp
323 .LP
324 To attach \fBDMA\fR resources to a preallocated packet, use:
326 .sp
327 .in +2
328 .nf
329 pkt = scsi_init_pkt(&devp->sd_address, old_pkt, bp, 0,
330 0, 0, 0, sd_runout, (caddr_t) sd_unit);
331 .fi
332 .in -2
334 .LP
335 \fBExample 4 \fRAllocating a Packet with Consistent \fBDMA\fR Resources
336 Attached
337 .sp
338 .LP
339 Since the packet is already allocated, the \fIcmdlen\fR, \fIstatuslen\fR and
340 \fIprivatelen\fR are \fB0\fR. To allocate a packet with consistent \fBDMA\fR
341 resources attached, use:
343 .sp
344 .in +2
345 .nf
346 bp = scsi_alloc_consistent_buf(&devp->sd_address, NULL,
347 SENSE_LENGTH, B_READ, SLEEP_FUNC, NULL);
348 pkt = scsi_init_pkt(&devp->sd_address, NULL, bp, CDB_GROUP0,
349 sizeof(struct scsi_arq_status), sizeof (struct my_pkt_private *),
350 PKT_CONSISTENT, SLEEP_FUNC, NULL);
351 .fi
352 .in -2
354 .LP
355 \fBExample 5 \fRAllocating a Packet with Partial \fBDMA\fR Resources Attached
356 .sp
357 .LP
358 To allocate a packet with partial \fBDMA\fR resources attached, use:
360 .sp
361 .in +2
362 .nf
363 my_pkt = scsi_init_pkt(&devp->sd_address, NULL, bp, CDB_GROUP0,
364 1, sizeof (struct buf *), PKT_DMA_PARTIAL,
365 SLEEP_FUNC, NULL);
366 .fi
367 .in -2
369 .SH SEE ALSO
370 .sp
371 .LP
372 \fBscsi_alloc_consistent_buf\fR(9F), \fBscsi_destroy_pkt\fR(9F),
373 \fBscsi_dmaget\fR(9F), \fBscsi_pktalloc\fR(9F), \fBbuf\fR(9S),
374 \fBddi_dma_req\fR(9S), \fBscsi_address\fR(9S), \fBscsi_pkt\fR(9S)
375 .sp
376 .LP
377 \fIWriting Device Drivers\fR
378 .SH NOTES
379 .sp
380 .LP
381 If a \fBDMA\fR allocation request fails with \fBDDI_DMA_NOMAPPING\fR, the
382 \fBB_ERROR\fR flag will be set in \fIbp\fR, and the \fBb_error\fR field will be
383 set to \fBEFAULT\fR.
384 .sp
385 .LP
386 If a \fBDMA\fR allocation request fails with \fBDDI_DMA_TOOBIG\fR, the
387 \fBB_ERROR\fR flag will be set in \fIbp\fR, and the \fBb_error\fR field will be
388 set to \fBEINVAL\fR.