1.\"
2.\" Copyright (c) 1995, 1996, 1997, 1998, 2000
3.\" Justin T. Gibbs. All rights reserved.
4.\"
5.\" Redistribution and use in source and binary forms, with or without
6.\" modification, are permitted provided that the following conditions
7.\" are met:
8.\" 1. Redistributions of source code must retain the above copyright
9.\" notice, this list of conditions and the following disclaimer.
10.\" 2. Redistributions in binary form must reproduce the above copyright
11.\" notice, this list of conditions and the following disclaimer in the
12.\" documentation and/or other materials provided with the distribution.
13.\" 3. The name of the author may not be used to endorse or promote products
14.\" derived from this software without specific prior written permission.
15.\"
16.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26.\"
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27.\" $FreeBSD: head/share/man/man4/ahc.4 140561 2005-01-21 08:36:40Z ru $
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| 27.\" $FreeBSD: head/share/man/man4/ahc.4 158762 2006-05-20 09:39:28Z brueffer $ |
28.\"
29.Dd July 4, 2004
30.Dt AHC 4
31.Os
32.Sh NAME
33.Nm ahc
34.Nd Adaptec VL/EISA/PCI SCSI host adapter driver
35.Sh SYNOPSIS
|
36To compile this driver into the kernel,
37place the following lines in your
38kernel configuration file:
39.Bd -ragged -offset indent
40.Cd "device scbus"
41.Cd "device ahc"
42.Pp |
43For one or more VL/EISA cards:
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37.Cd device eisa
38.Cd device ahc
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| 44.Cd "device eisa" |
45.Pp
46For one or more PCI cards:
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41.Cd device pci
42.Cd device ahc
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| 47.Cd "device pci" |
48.Pp
49To allow PCI adapters to use memory mapped I/O if enabled:
50.Cd options AHC_ALLOW_MEMIO
51.Pp
52To configure one or more controllers to assume the target role:
53.Cd options AHC_TMODE_ENABLE <bitmask of units>
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| 54.Ed |
55.Pp
|
50For one or more SCSI busses:
51.Cd device scbus
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56Alternatively, to load the driver as a
57module at boot time, place the following lines in
58.Xr loader.conf 5 :
59.Bd -literal -offset indent
60ahc_load="YES"
61ahc_eisa_load="YES"
62ahc_isa_load="YES"
63ahc_pci_load="YES"
64.Ed |
65.Sh DESCRIPTION
66This driver provides access to the
67.Tn SCSI
68bus(es) connected to the Adaptec AIC77xx and AIC78xx
69host adapter chips.
70.Pp
71Driver features include support for twin and wide busses,
72fast, ultra or ultra2 synchronous transfers depending on controller type,
73tagged queueing, SCB paging, and target mode.
74.Pp
75Memory mapped I/O can be enabled for PCI devices with the
76.Dq Dv AHC_ALLOW_MEMIO
77configuration option.
78Memory mapped I/O is more efficient than the alternative, programmed I/O.
79Most PCI BIOSes will map devices so that either technique for communicating
80with the card is available.
81In some cases,
82usually when the PCI device is sitting behind a PCI->PCI bridge,
83the BIOS may fail to properly initialize the chip for memory mapped I/O.
84The typical symptom of this problem is a system hang if memory mapped I/O
85is attempted.
86Most modern motherboards perform the initialization correctly and work fine
87with this option enabled.
88.Pp
89Individual controllers may be configured to operate in the target role
90through the
91.Dq Dv AHC_TMODE_ENABLE
92configuration option.
93The value assigned to this option should be a bitmap
94of all units where target mode is desired.
95For example, a value of 0x25, would enable target mode on units 0, 2, and 5.
96A value of 0x8a enables it for units 1, 3, and 7.
97.Pp
98Per target configuration performed in the
99.Tn SCSI-Select
100menu, accessible at boot
101in
102.No non- Ns Tn EISA
103models,
104or through an
105.Tn EISA
106configuration utility for
107.Tn EISA
108models,
109is honored by this driver.
110This includes synchronous/asynchronous transfers,
111maximum synchronous negotiation rate,
112wide transfers,
113disconnection,
114the host adapter's SCSI ID,
115and,
116in the case of
117.Tn EISA
118Twin Channel controllers,
119the primary channel selection.
120For systems that store non-volatile settings in a system specific manner
121rather than a serial eeprom directly connected to the aic7xxx controller,
122the
123.Tn BIOS
124must be enabled for the driver to access this information.
125This restriction applies to all
126.Tn EISA
127and many motherboard configurations.
128.Pp
129Note that I/O addresses are determined automatically by the probe routines,
130but care should be taken when using a 284x
131.Pq Tn VESA No local bus controller
132in an
133.Tn EISA
134system.
135The jumpers setting the I/O area for the 284x should match the
136.Tn EISA
137slot into which the card is inserted to prevent conflicts with other
138.Tn EISA
139cards.
140.Pp
141Performance and feature sets vary throughout the aic7xxx product line.
142The following table provides a comparison of the different chips supported
143by the
144.Nm
145driver.
146Note that wide and twin channel features, although always supported
147by a particular chip, may be disabled in a particular motherboard or card
148design.
149.Pp
150.Bd -ragged -offset indent
151.Bl -column "aic7770 " "10 " "EISA/VL " "10MHz " "16bit " "SCBs " Features
152.Em "Chip MIPS Bus MaxSync MaxWidth SCBs Features"
153aic7770 10 EISA/VL 10MHz 16Bit 4 1
154aic7850 10 PCI/32 10MHz 8Bit 3
155aic7860 10 PCI/32 20MHz 8Bit 3
156aic7870 10 PCI/32 10MHz 16Bit 16
157aic7880 10 PCI/32 20MHz 16Bit 16
158aic7890 20 PCI/32 40MHz 16Bit 16 3 4 5 6 7 8
159aic7891 20 PCI/64 40MHz 16Bit 16 3 4 5 6 7 8
160aic7892 20 PCI/64 80MHz 16Bit 16 3 4 5 6 7 8
161aic7895 15 PCI/32 20MHz 16Bit 16 2 3 4 5
162aic7895C 15 PCI/32 20MHz 16Bit 16 2 3 4 5 8
163aic7896 20 PCI/32 40MHz 16Bit 16 2 3 4 5 6 7 8
164aic7897 20 PCI/64 40MHz 16Bit 16 2 3 4 5 6 7 8
165aic7899 20 PCI/64 80MHz 16Bit 16 2 3 4 5 6 7 8
166.El
167.Pp
168.Bl -enum -compact
169.It
170Multiplexed Twin Channel Device - One controller servicing two busses.
171.It
172Multi-function Twin Channel Device - Two controllers on one chip.
173.It
174Command Channel Secondary DMA Engine - Allows scatter gather list and
175SCB prefetch.
176.It
17764 Byte SCB Support - SCSI CDB is embedded in the SCB to eliminate an extra DMA.
178.It
179Block Move Instruction Support - Doubles the speed of certain sequencer
180operations.
181.It
182.Sq Bayonet
183style Scatter Gather Engine - Improves S/G prefetch performance.
184.It
185Queuing Registers - Allows queueing of new transactions without pausing the
186sequencer.
187.It
188Multiple Target IDs - Allows the controller to respond to selection as a
189target on multiple SCSI IDs.
190.El
191.Ed
192.Sh HARDWARE
193The
194.Nm
195driver supports the following
196.Tn SCSI
197host adapter chips and
198.Tn SCSI
199controller cards:
200.Pp
201.Bl -bullet -compact
202.It
203Adaptec
204.Tn AIC7770
205host adapter chip
206.It
207Adaptec
208.Tn AIC7850
209host adapter chip
210.It
211Adaptec
212.Tn AIC7860
213host adapter chip
214.It
215Adaptec
216.Tn AIC7870
217host adapter chip
218.It
219Adaptec
220.Tn AIC7880
221host adapter chip
222.It
223Adaptec
224.Tn AIC7890
225host adapter chip
226.It
227Adaptec
228.Tn AIC7891
229host adapter chip
230.It
231Adaptec
232.Tn AIC7892
233host adapter chip
234.It
235Adaptec
236.Tn AIC7895
237host adapter chip
238.It
239Adaptec
240.Tn AIC7896
241host adapter chip
242.It
243Adaptec
244.Tn AIC7897
245host adapter chip
246.It
247Adaptec
248.Tn AIC7899
249host adapter chip
250.It
251Adaptec
252.Tn 274X(W)
253.It
254Adaptec
255.Tn 274X(T)
256.It
257Adaptec
258.Tn 284X
259.It
260Adaptec
261.Tn 2910
262.It
263Adaptec
264.Tn 2915
265.It
266Adaptec
267.Tn 2920
268.It
269Adaptec
270.Tn 2930C
271.It
272Adaptec
273.Tn 2930U2
274.It
275Adaptec
276.Tn 2940
277.It
278Adaptec
279.Tn 2940J
280.It
281Adaptec
282.Tn 2940N
283.It
284Adaptec
285.Tn 2940U
286.It
287Adaptec
288.Tn 2940AU
289.It
290Adaptec
291.Tn 2940UW
292.It
293Adaptec
294.Tn 2940UW Dual
295.It
296Adaptec
297.Tn 2940UW Pro
298.It
299Adaptec
300.Tn 2940U2W
301.It
302Adaptec
303.Tn 2940U2B
304.It
305Adaptec
306.Tn 2950U2W
307.It
308Adaptec
309.Tn 2950U2B
310.It
311Adaptec
312.Tn 19160B
313.It
314Adaptec
315.Tn 29160B
316.It
317Adaptec
318.Tn 29160N
319.It
320Adaptec
321.Tn 3940
322.It
323Adaptec
324.Tn 3940U
325.It
326Adaptec
327.Tn 3940AU
328.It
329Adaptec
330.Tn 3940UW
331.It
332Adaptec
333.Tn 3940AUW
334.It
335Adaptec
336.Tn 3940U2W
337.It
338Adaptec
339.Tn 3950U2
340.It
341Adaptec
342.Tn 3960
343.It
344Adaptec
345.Tn 39160
346.It
347Adaptec
348.Tn 3985
349.It
350Adaptec
351.Tn 4944UW
352.It
353NEC PC-9821Xt13 (PC-98)
354.It
355NEC RvII26 (PC-98)
356.It
357NEC PC-9821X-B02L/B09 (PC-98)
358.It
359NEC SV-98/2-B03 (PC-98)
360.It
361Many motherboards with on-board
362.Tn SCSI
363support
364.El
365.Sh SCSI CONTROL BLOCKS (SCBs)
366Every transaction sent to a device on the SCSI bus is assigned a
367.Sq SCSI Control Block
368(SCB).
369The SCB contains all of the information required by the
370controller to process a transaction.
371The chip feature table lists
372the number of SCBs that can be stored in on-chip memory.
373All chips
374with model numbers greater than or equal to 7870 allow for the on chip
375SCB space to be augmented with external SRAM up to a maximum of 255 SCBs.
376Very few Adaptec controller configurations have external SRAM.
377.Pp
378If external SRAM is not available, SCBs are a limited resource.
379Using the SCBs in a straight forward manner would only allow the driver to
380handle as many concurrent transactions as there are physical SCBs.
381To fully utilize the SCSI bus and the devices on it,
382requires much more concurrency.
383The solution to this problem is
384.Em SCB Paging ,
385a concept similar to memory paging.
386SCB paging takes advantage of
387the fact that devices usually disconnect from the SCSI bus for long
388periods of time without talking to the controller.
389The SCBs for disconnected transactions are only of use to the controller
390when the transfer is resumed.
391When the host queues another transaction
392for the controller to execute, the controller firmware will use a
393free SCB if one is available.
394Otherwise, the state of the most recently
395disconnected (and therefore most likely to stay disconnected) SCB is
396saved, via dma, to host memory, and the local SCB reused to start
397the new transaction.
398This allows the controller to queue up to
399255 transactions regardless of the amount of SCB space.
400Since the
401local SCB space serves as a cache for disconnected transactions, the
402more SCB space available, the less host bus traffic consumed saving
403and restoring SCB data.
404.Sh SEE ALSO
405.Xr aha 4 ,
406.Xr ahb 4 ,
407.Xr cd 4 ,
408.Xr da 4 ,
409.Xr sa 4 ,
410.Xr scsi 4
411.Sh HISTORY
412The
413.Nm
414driver appeared in
415.Fx 2.0 .
416.Sh AUTHORS
417The
418.Nm
419driver, the
420.Tn AIC7xxx
421sequencer-code assembler,
422and the firmware running on the aic7xxx chips was written by
423.An Justin T. Gibbs .
424.Sh BUGS
425Some Quantum drives (at least the Empire 2100 and 1080s) will not run on an
426.Tn AIC7870
427Rev B in synchronous mode at 10MHz.
428Controllers with this problem have a
42942 MHz clock crystal on them and run slightly above 10MHz.
430This confuses the drive and hangs the bus.
431Setting a maximum synchronous negotiation rate of 8MHz in the
432.Tn SCSI-Select
433utility will allow normal operation.
434.Pp
435Although the Ultra2 and Ultra160 products have sufficient instruction
436ram space to support both the initiator and target roles concurrently,
437this configuration is disabled in favor of allowing the target role
438to respond on multiple target ids.
439A method for configuring dual role mode should be provided.
440.Pp
441Tagged Queuing is not supported in target mode.
442.Pp
443Reselection in target mode fails to function correctly on all high
444voltage differential boards as shipped by Adaptec.
445Information on
446how to modify HVD board to work correctly in target mode is available
447from Adaptec.
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