1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
|
SUBJECT
-------
AM53/79C974 PC-SCSI Driver
DISCLAIMER
----------
*** THIS SHOULD BE CONSIDERED AS BETA SOFTWARE ***
*** USE AT YOUR OWN RISK! ***
Copyright
---------
The architecture and much of the code of this device driver was
originally developed by Drew Eckhardt for the NCR5380. The
following copyrights apply:
For the architecture and all pieces of code which can also be found
in the NCR5380 device driver:
Copyright 1993, Drew Eckhardt
Visionary Computing
(Unix and Linux consulting and custom programming)
drew@colorado.edu
+1 (303) 666-5836
The AM53C974_nobios_detect code was originally developed by
Robin Cutshaw (robin@xfree86.org) and is used here in a
slightly modified form.
For the remaining code:
Copyright 1994, D. Frieauff
EMail: fri@rsx42sun0.dofn.de
Phone: x49-7545-8-2256 , x49-7541-42305
Version
-------
AM53/79C974 (PC-SCSI) Linux driver ALPHA release 0.5, 19 November 1995
Changelog
---------
0.1 -> 0.2:
- Extended message handling re-written to eliminate 'invalid message 17' bug
- Parameters of AM53C974_intr adapted
- Debug messages structured
- Spelling improved
0.2 -> 0.3:
- README file updated -- please read this file up to the end!
- Automatic scanning of io_port and irq implemented; no need for BIOS32
anymore
- Improved configuration (now via LILO parameter string)
- Cleanup of probing and initialization code
- Improved sync. negotiation (can be setup individually for every device)
- Improved/ debugged code for reception of ext. messages
0.3 -> 0.4:
- Improved PCI probing and initialization code
- Compatibility changes for Linux 1.3.x
0.4 -> 0.5:
- Compatibility changes for Linux 1.3.42
Bugs & Todo
-----------
- Add proc info function
- Support SCSI-2 tagged queuing
- Finalize abort code
Features
--------
This driver supports asynchronous and synchronous SCSI-I and SCSI-II
devices. It is capable of transfer rate and synchronous negotiation
(see below). The driver supports scatter-gather. Transfers are DMA
based, but do not (yet) make use of the AM53/79C974 MDL mode.
Max. transfer rate is 10MHz (whatever this is in real life). The
transfer rate is negotiated with each device (see dmesg output). The
AM53/79C974 has a 96-byte DMA FIFO to the PCI bus and a 16-byte SCSI
FIFO. It provides active negation and glitch suppression functions.
Burst DMA transfer rate is 132 MBytes/sec.
Configuration
-------------
The following communication characteristics can be set individually
for every SCSI device on the bus:
- enable/disable sync. negotiation
- transfer rate
- asynchronous or synchronous communication
- in case of sync. communication, the sync. offset
The sync. offset specifies the number of bytes that can be sent or
received from the SCSI bus without ACK resp. REQ signal.
CAUTION: USING SYNCHRONOUS MODE ON LONG SCSI CABLES MAY CAUSE
COMMUNICATION PROBLEMS LEADING TO LOSS OF DATA.
The default setting of the SCSI communication parameters is as follows:
- no negotiation
- 5.0 MHz transfer rate
- asynchronous mode
- zero offset
The parameters can be modified by passing a string with the following
syntax to the kernel:
AM53C974=host-scsi-id,target-scsi-id,max-rate,max-offset
The parameters will be used by the driver as negotiation basis. The
range of the rate parameter is 3 to 10 MHz. The range of the
sync. offset parameter is 0 to 15 bytes. A value of 0 denotes
asynchronous comm. mode. If the target cannot cope with the specified
transfer rate, sync. mode or sync. offset, the negotiation result
will differ from the specified values. The negotiation result is
printed out at the end of the negotiation process (to read it, use the
dmesg program or the appropriate syslog). The parameter strings
(blank separated) can be passed to the kernel at the LILO prompt, or
as part of the LILO configuration file.
For example, the string "AM53C974=7,2,8,15" would be interpreted as
follows:
For communication between the controller with SCSI-ID 7 and the
device with SCSI-ID 2 a transfer rate of 8MHz in synchronous mode with
max. 15 bytes offset should be negotiated.
As an example, here my LILO configuration file:
boot = /dev/sda
compact
#prompt
delay = 50 # optional, for systems that boot very quickly
vga = normal # force sane state
ramdisk = 0 # paranoia setting
root = current # use "current" root
image = /usr/src/linux/arch/i386/boot/zImage
label = linux
append = "AM53C974=7,0,10,0 AM53C974=7,1,10,0 AM53C974=7,2,10,15 AM53C974=7,4,10,0 AM53C974=7,5,10,0"
read-only
other = /dev/sda4
label = os2
other = /dev/sdb3
loader = /boot/any_d.b
table = /dev/sdb
label = setup
The same parameters at the LILO prompt:
LILO boot: linux AM53C974=7,0,10,0 AM53C974=7,1,10,0 AM53C974=7,2,10,15 AM53C974=7,4,10,0 AM53C974=7,5,10,0
You can override parameters specified in the LILO configuration file
by parameters specified on the LILO command line.
BIOS usage
----------
Version 0.4 of the driver will use the BIOS, if available. Otherwise
it will try its internal PCI scan and access routines. The driver
assumes that the controller's SCSI-ID (usually 7) has been correctly
loaded by the BIOS into the controller's register during system
boot. If the driver detects that the controller's SCSI ID is not '7'
it will print out a warning. If this happens to you please correct
setting of the controller's SCSI-ID. If it is wrong, then edit the
AM53C974_SCSI_ID definition in file AM53C974.h accordingly.
Test environment
----------------
This driver was tested on a Compaq XL566 with the following SCSI configuration:
2 x HP C2247 fixed disk (internal, rate=10MHz, async.)
1 x Micropolis 1624 fixed disk (external, rate=8MHz, sync., offset=15 bytes)
1 x Wangtek W5525ES cartridge streamer (internal, rate=5MHz, async.)
1 x Toshiba XM-3301B CD-ROM (external, rate=5MHz, async.)
Known problems
--------------
- Compaq/Matsushita CD-ROM:
Use of this device with AM53C974 driver version 0.2 caused the kernel to
hang during Linux boot. If you encounter the problem, don't enable sync.
negotiation with the CD-ROM, i.e. simply don't specify comm. parameters
for this device on the LILO command line or configuration file.
The driver will thus use its default for the CD-ROM, which is 5MHz
transfer rate async and no sync. negotiation.
- Some disks cause problems.
What to do if there is a SCSI problem possibly related to the driver
--------------------------------------------------------------------
Read Klaus Liedl's WWW page (http://www-c724.uibk.ac.at/XL/). In case
this does not help: Send me a complete description of the problem,
including your SCSI configuration plus as much debugging information
as possible. Don't wait until I ask you for this information. To
enable the generation of debugging output, remove the comments from
the following definitions in the AM53C974.h file:
AM53C974_DEBUG
AM53C974_DEBUG_MSG
AM53C974_DEBUG_KEYWAIT
AM53C974_DEBUG_INFO
AM53C974_DEBUG_INTR
With these definitions enabled, the driver will enter single-step mode
during Linux boot. Use the spacebar for stepping. Take note of at
least the last 10 printout sections (marked by dashes) before the
crash/hangup or whatever happens and send me all of this information
via email. If the system can boot, use the syslogd daemon to record
the debugging output. Maybe you can use the ramdisk for this purpose
too (if necessary, kindly ask K. Liedl (Klaus.Liedl@uibk.ac.at) for
support, he knows how to do it -- I never tried). Stay in email
contact with me. Be aware that the following weeks/months could be the
worst of your life. Note: If single-stepping takes up too much time,
you can try to let the driver catch the problem by pressing the 'r'
key. The driver will automatically enter single-step mode if it has
detected something weird.
Author's Contact Address
-----------------------
Email: fri@rsx42sun0.dofn.de
Phone: x49-7545-2256 (office), x49-7541-42305 (home)
Home address: D. Frieauff, Stockerholzstr. 27, 88048 Friedrichshafen, Germany
!!!! Important Notice !!!!
-----------------------------
- Klaus Liedl maintains an excellent WWW page about Linux on Compaq XL.
It includes an FAQ, lots of tips & tricks as well as downloadable
boot disk images. The URL is: http://www-c724.uibk.ac.at/XL/
- Volunteer wanted for further maintenance of this driver software. I
don't have the time anymore to do serious support as some of you will know.
Literature
----------
- AMD AM53C974 PC-SCSI Technical Manual, publication #18624B
- Amendment to the AMD AM53C974 PC-SCSI Technical Manual
- AMD AM79C974 PC-NET Datasheet, publication #18681
- Amendment to the AMD AM79C974 PC-NET Datasheet
THANKS to
---------
- Drew Eckhardt, Robin Cutshaw, K. Liedl, Robert J. Pappas, A. Grenier,
Mark Stockton, David C. Niemi, Ben Craft, and many others who have helped
|
