1.. SPDX-License-Identifier: GPL-2.0
2
3=================================================
4The Linux NCR53C8XX/SYM53C8XX drivers README file
5=================================================
6
7Written by Gerard Roudier <groudier@free.fr>
8
921 Rue Carnot
10
1195170 DEUIL LA BARRE - FRANCE
12
1329 May 1999
14
15.. Contents:
16
17   1.  Introduction
18   2.  Supported chips and SCSI features
19   3.  Advantages of the enhanced 896 driver
20         3.1 Optimized SCSI SCRIPTS
21         3.2 New features of the SYM53C896 (64 bit PCI dual LVD SCSI controller)
22   4.  Memory mapped I/O versus normal I/O
23   5.  Tagged command queueing
24   6.  Parity checking
25   7.  Profiling information
26   8.  Control commands
27         8.1  Set minimum synchronous period
28         8.2  Set wide size
29         8.3  Set maximum number of concurrent tagged commands
30         8.4  Set order type for tagged command
31         8.5  Set debug mode
32         8.6  Clear profile counters
33         8.7  Set flag (no_disc)
34         8.8  Set verbose level
35         8.9  Reset all logical units of a target
36         8.10 Abort all tasks of all logical units of a target
37   9.  Configuration parameters
38   10. Boot setup commands
39         10.1 Syntax
40         10.2 Available arguments
41                10.2.1  Master parity checking
42                10.2.2  Scsi parity checking
43                10.2.3  Scsi disconnections
44                10.2.4  Special features
45                10.2.5  Ultra SCSI support
46                10.2.6  Default number of tagged commands
47                10.2.7  Default synchronous period factor
48                10.2.8  Negotiate synchronous with all devices
49                10.2.9  Verbosity level
50                10.2.10 Debug mode
51                10.2.11 Burst max
52                10.2.12 LED support
53                10.2.13 Max wide
54                10.2.14 Differential mode
55                10.2.15 IRQ mode
56                10.2.16 Reverse probe
57                10.2.17 Fix up PCI configuration space
58                10.2.18 Serial NVRAM
59                10.2.19 Check SCSI BUS
60                10.2.20 Exclude a host from being attached
61                10.2.21 Suggest a default SCSI id for hosts
62                10.2.22 Enable use of IMMEDIATE ARBITRATION
63         10.3 Advised boot setup commands
64         10.4 PCI configuration fix-up boot option
65         10.5 Serial NVRAM support boot option
66         10.6 SCSI BUS checking boot option
67         10.7 IMMEDIATE ARBITRATION boot option
68   11. Some constants and flags of the ncr53c8xx.h header file
69   12. Installation
70   13. Architecture dependent features
71   14. Known problems
72         14.1 Tagged commands with Iomega Jaz device
73         14.2 Device names change when another controller is added
74         14.3 Using only 8 bit devices with a WIDE SCSI controller.
75         14.4 Possible data corruption during a Memory Write and Invalidate
76         14.5 IRQ sharing problems
77   15. SCSI problem troubleshooting
78         15.1 Problem tracking
79         15.2 Understanding hardware error reports
80   16. Synchronous transfer negotiation tables
81         16.1 Synchronous timings for 53C875 and 53C860 Ultra-SCSI controllers
82         16.2 Synchronous timings for fast SCSI-2 53C8XX controllers
83   17. Serial NVRAM support (by Richard Waltham)
84         17.1 Features
85         17.2 Symbios NVRAM layout
86         17.3 Tekram  NVRAM layout
87   18. Support for Big Endian
88         18.1 Big Endian CPU
89         18.2 NCR chip in Big Endian mode of operations
90
911. Introduction
92===============
93
94The initial Linux ncr53c8xx driver has been a port of the ncr driver from
95FreeBSD that has been achieved in November 1995 by:
96
97	- Gerard Roudier              <groudier@free.fr>
98
99The original driver has been written for 386bsd and FreeBSD by:
100
101        - Wolfgang Stanglmeier        <wolf@cologne.de>
102        - Stefan Esser                <se@mi.Uni-Koeln.de>
103
104It is now available as a bundle of 2 drivers:
105
106- ncr53c8xx generic driver that supports all the SYM53C8XX family including
107  the earliest 810 rev. 1, the latest 896 (2 channel LVD SCSI controller) and
108  the new 895A (1 channel LVD SCSI controller).
109- sym53c8xx enhanced driver (a.k.a. 896 drivers) that drops support of oldest
110  chips in order to gain advantage of new features, as LOAD/STORE instructions
111  available since the 810A and hardware phase mismatch available with the
112  896 and the 895A.
113
114You can find technical information about the NCR 8xx family in the
115PCI-HOWTO written by Michael Will and in the SCSI-HOWTO written by
116Drew Eckhardt.
117
118Information about new chips is available at LSILOGIC web server:
119
120          - http://www.lsilogic.com/
121
122SCSI standard documentations are available at SYMBIOS ftp server:
123
124          - ftp://ftp.symbios.com/
125
126Useful SCSI tools written by Eric Youngdale are available at tsx-11:
127
128          - ftp://tsx-11.mit.edu/pub/linux/ALPHA/scsi/scsiinfo-X.Y.tar.gz
129          - ftp://tsx-11.mit.edu/pub/linux/ALPHA/scsi/scsidev-X.Y.tar.gz
130
131These tools are not ALPHA but quite clean and work quite well.
132It is essential you have the 'scsiinfo' package.
133
134This short documentation describes the features of the generic and enhanced
135drivers, configuration parameters and control commands available through
136the proc SCSI file system read / write operations.
137
138This driver has been tested OK with linux/i386, Linux/Alpha and Linux/PPC.
139
140Latest driver version and patches are available at:
141
142          - ftp://ftp.tux.org/pub/people/gerard-roudier
143
144or
145
146          - ftp://ftp.symbios.com/mirror/ftp.tux.org/pub/tux/roudier/drivers
147
148I am not a native speaker of English and there are probably lots of
149mistakes in this README file. Any help will be welcome.
150
151
1522. Supported chips and SCSI features
153====================================
154
155The following features are supported for all chips:
156
157	- Synchronous negotiation
158	- Disconnection
159	- Tagged command queuing
160	- SCSI parity checking
161	- Master parity checking
162
163"Wide negotiation" is supported for chips that allow it.  The
164following table shows some characteristics of NCR 8xx family chips
165and what drivers support them.
166
167+--------+-----------+-----+-----------+------------+------------+------------+
168|        |           |     |           |            |Supported by|Supported by|
169|        |On board   |     |           |            |the generic |the enhanced|
170|Chip    |SDMS BIOS  |Wide |SCSI std.  | Max. sync  |driver      |driver      |
171+--------+-----------+-----+-----------+------------+------------+------------+
172|810     |  N        | N   |  FAST10   | 10 MB/s    |    Y       |    N       |
173+--------+-----------+-----+-----------+------------+------------+------------+
174|810A    |  N        | N   |  FAST10   | 10 MB/s    |    Y       |    Y       |
175+--------+-----------+-----+-----------+------------+------------+------------+
176|815     |  Y        | N   |  FAST10   | 10 MB/s    |    Y       |    N       |
177+--------+-----------+-----+-----------+------------+------------+------------+
178|825     |  Y        | Y   |  FAST10   | 20 MB/s    |    Y       |    N       |
179+--------+-----------+-----+-----------+------------+------------+------------+
180|825A    |  Y        | Y   |  FAST10   | 20 MB/s    |    Y       |    Y       |
181+--------+-----------+-----+-----------+------------+------------+------------+
182|860     |  N        | N   |  FAST20   | 20 MB/s    |    Y       |    Y       |
183+--------+-----------+-----+-----------+------------+------------+------------+
184|875     |  Y        | Y   |  FAST20   | 40 MB/s    |    Y       |    Y       |
185+--------+-----------+-----+-----------+------------+------------+------------+
186|876     |  Y        | Y   |  FAST20   | 40 MB/s    |    Y       |    Y       |
187+--------+-----------+-----+-----------+------------+------------+------------+
188|895     |  Y        | Y   |  FAST40   | 80 MB/s    |    Y       |    Y       |
189+--------+-----------+-----+-----------+------------+------------+------------+
190|895A    |  Y        | Y   |  FAST40   | 80 MB/s    |    Y       |    Y       |
191+--------+-----------+-----+-----------+------------+------------+------------+
192|896     |  Y        | Y   |  FAST40   | 80 MB/s    |    Y       |    Y       |
193+--------+-----------+-----+-----------+------------+------------+------------+
194|897     |  Y        | Y   |  FAST40   | 80 MB/s    |    Y       |    Y       |
195+--------+-----------+-----+-----------+------------+------------+------------+
196|1510D   |  Y        | Y   |  FAST40   | 80 MB/s    |    Y       |    Y       |
197+--------+-----------+-----+-----------+------------+------------+------------+
198|1010    |  Y        | Y   |  FAST80   |160 MB/s    |    N       |    Y       |
199+--------+-----------+-----+-----------+------------+------------+------------+
200|1010_66 |  Y        | Y   |  FAST80   |160 MB/s    |    N       |    Y       |
201|[1]_    |           |     |           |            |            |            |
202+--------+-----------+-----+-----------+------------+------------+------------+
203
204.. [1] Chip supports 33MHz and 66MHz PCI buses.
205
206
207Summary of other supported features:
208
209:Module:                allow to load the driver
210:Memory mapped I/O:     increases performance
211:Profiling information: read operations from the proc SCSI file system
212:Control commands:      write operations to the proc SCSI file system
213:Debugging information: written to syslog (expert only)
214:Serial NVRAM:          Symbios and Tekram formats
215
216- Scatter / gather
217- Shared interrupt
218- Boot setup commands
219
220
2213. Advantages of the enhanced 896 driver
222========================================
223
2243.1 Optimized SCSI SCRIPTS
225--------------------------
226
227The 810A, 825A, 875, 895, 896 and 895A support new SCSI SCRIPTS instructions
228named LOAD and STORE that allow to move up to 1 DWORD from/to an IO register
229to/from memory much faster that the MOVE MEMORY instruction that is supported
230by the 53c7xx and 53c8xx family.
231The LOAD/STORE instructions support absolute and DSA relative addressing
232modes.  The SCSI SCRIPTS had been entirely rewritten using LOAD/STORE instead
233of MOVE MEMORY instructions.
234
2353.2 New features of the SYM53C896 (64 bit PCI dual LVD SCSI controller)
236-----------------------------------------------------------------------
237
238The 896 and the 895A allows handling of the phase mismatch context from
239SCRIPTS (avoids the phase mismatch interrupt that stops the SCSI processor
240until the C code has saved the context of the transfer).
241Implementing this without using LOAD/STORE instructions would be painful
242and I didn't even want to try it.
243
244The 896 chip supports 64 bit PCI transactions and addressing, while the
245895A supports 32 bit PCI transactions and 64 bit addressing.
246The SCRIPTS processor of these chips is not true 64 bit, but uses segment
247registers for bit 32-63. Another interesting feature is that LOAD/STORE
248instructions that address the on-chip RAM (8k) remain internal to the chip.
249
250Due to the use of LOAD/STORE SCRIPTS instructions, this driver does not
251support the following chips:
252
253- SYM53C810 revision < 0x10 (16)
254- SYM53C815 all revisions
255- SYM53C825 revision < 0x10 (16)
256
2574. Memory mapped I/O versus normal I/O
258======================================
259
260Memory mapped I/O has less latency than normal I/O.  Since
261linux-1.3.x, memory mapped I/O is used rather than normal I/O.  Memory
262mapped I/O seems to work fine on most hardware configurations, but
263some poorly designed motherboards may break this feature.
264
265The configuration option CONFIG_SCSI_NCR53C8XX_IOMAPPED forces the
266driver to use normal I/O in all cases.
267
268
2695. Tagged command queueing
270==========================
271
272Queuing more than 1 command at a time to a device allows it to perform
273optimizations based on actual head positions and its mechanical
274characteristics. This feature may also reduce average command latency.
275In order to really gain advantage of this feature, devices must have
276a reasonable cache size (No miracle is to be expected for a low-end
277hard disk with 128 KB or less).
278Some known SCSI devices do not properly support tagged command queuing.
279Generally, firmware revisions that fix this kind of problems are available
280at respective vendor web/ftp sites.
281All I can say is that the hard disks I use on my machines behave well with
282this driver with tagged command queuing enabled:
283
284- IBM S12 0662
285- Conner 1080S
286- Quantum Atlas I
287- Quantum Atlas II
288
289If your controller has NVRAM, you can configure this feature per target
290from the user setup tool. The Tekram Setup program allows to tune the
291maximum number of queued commands up to 32. The Symbios Setup only allows
292to enable or disable this feature.
293
294The maximum number of simultaneous tagged commands queued to a device
295is currently set to 8 by default.  This value is suitable for most SCSI
296disks.  With large SCSI disks (>= 2GB, cache >= 512KB, average seek time
297<= 10 ms), using a larger value may give better performances.
298
299The sym53c8xx driver supports up to 255 commands per device, and the
300generic ncr53c8xx driver supports up to 64, but using more than 32 is
301generally not worth-while, unless you are using a very large disk or disk
302array. It is noticeable that most of recent hard disks seem not to accept
303more than 64 simultaneous commands. So, using more than 64 queued commands
304is probably just resource wasting.
305
306If your controller does not have NVRAM or if it is managed by the SDMS
307BIOS/SETUP, you can configure tagged queueing feature and device queue
308depths from the boot command-line. For example::
309
310  ncr53c8xx=tags:4/t2t3q15-t4q7/t1u0q32
311
312will set tagged commands queue depths as follow:
313
314- target 2  all luns  on controller 0 --> 15
315- target 3  all luns  on controller 0 --> 15
316- target 4  all luns  on controller 0 -->  7
317- target 1  lun 0     on controller 1 --> 32
318- all other target/lun                -->  4
319
320In some special conditions, some SCSI disk firmwares may return a
321QUEUE FULL status for a SCSI command. This behaviour is managed by the
322driver using the following heuristic:
323
324- Each time a QUEUE FULL status is returned, tagged queue depth is reduced
325  to the actual number of disconnected commands.
326
327- Every 1000 successfully completed SCSI commands, if allowed by the
328  current limit, the maximum number of queueable commands is incremented.
329
330Since QUEUE FULL status reception and handling is resource wasting, the
331driver notifies by default this problem to user by indicating the actual
332number of commands used and their status, as well as its decision on the
333device queue depth change.
334The heuristic used by the driver in handling QUEUE FULL ensures that the
335impact on performances is not too bad. You can get rid of the messages by
336setting verbose level to zero, as follow:
337
3381st method:
339	    boot your system using 'ncr53c8xx=verb:0' option.
340
3412nd method:
342	    apply "setverbose 0" control command to the proc fs entry
343            corresponding to your controller after boot-up.
344
3456. Parity checking
346==================
347
348The driver supports SCSI parity checking and PCI bus master parity
349checking.  These features must be enabled in order to ensure safe data
350transfers.  However, some flawed devices or mother boards will have
351problems with parity. You can disable either PCI parity or SCSI parity
352checking by entering appropriate options from the boot command line.
353(See 10: Boot setup commands).
354
3557. Profiling information
356========================
357
358Profiling information is available through the proc SCSI file system.
359Since gathering profiling information may impact performances, this
360feature is disabled by default and requires a compilation configuration
361option to be set to Y.
362
363The device associated with a host has the following pathname::
364
365          /proc/scsi/ncr53c8xx/N     (N=0,1,2 ....)
366
367Generally, only 1 board is used on hardware configuration, and that device is::
368
369          /proc/scsi/ncr53c8xx/0
370
371However, if the driver has been made as module, the number of the
372hosts is incremented each time the driver is loaded.
373
374In order to display profiling information, just enter::
375
376         cat /proc/scsi/ncr53c8xx/0
377
378and you will get something like the following text::
379
380    General information:
381    Chip NCR53C810, device id 0x1, revision id 0x2
382    IO port address 0x6000, IRQ number 10
383    Using memory mapped IO at virtual address 0x282c000
384    Synchronous transfer period 25, max commands per lun 4
385    Profiling information:
386    num_trans    = 18014
387    num_kbytes   = 671314
388    num_disc     = 25763
389    num_break    = 1673
390    num_int      = 1685
391    num_fly      = 18038
392    ms_setup     = 4940
393    ms_data      = 369940
394    ms_disc      = 183090
395    ms_post      = 1320
396
397General information is easy to understand. The device ID and the
398revision ID identify the SCSI chip as follows:
399
400======= ============= ===========
401Chip    Device id     Revision Id
402======= ============= ===========
403810       0x1            <  0x10
404810A      0x1            >= 0x10
405815       0x4
406825       0x3            <  0x10
407860       0x6
408825A      0x3            >= 0x10
409875       0xf
410895       0xc
411======= ============= ===========
412
413The profiling information is updated upon completion of SCSI commands.
414A data structure is allocated and zeroed when the host adapter is
415attached. So, if the driver is a module, the profile counters are
416cleared each time the driver is loaded.  The "clearprof" command
417allows you to clear these counters at any time.
418
419The following counters are available:
420
421("num" prefix means "number of",
422"ms" means milli-seconds)
423
424num_trans
425	Number of completed commands
426	Example above: 18014 completed commands
427
428num_kbytes
429	Number of kbytes transferred
430	Example above: 671 MB transferred
431
432num_disc
433	Number of SCSI disconnections
434	Example above: 25763 SCSI disconnections
435
436num_break
437	number of script interruptions (phase mismatch)
438	Example above: 1673 script interruptions
439
440num_int
441	Number of interrupts other than "on the fly"
442	Example above: 1685 interruptions not "on the fly"
443
444num_fly
445	Number of interrupts "on the fly"
446	Example above: 18038 interruptions "on the fly"
447
448ms_setup
449	Elapsed time for SCSI commands setups
450	Example above: 4.94 seconds
451
452ms_data
453	Elapsed time for data transfers
454	Example above: 369.94 seconds spent for data transfer
455
456ms_disc
457	Elapsed time for SCSI disconnections
458	Example above: 183.09 seconds spent disconnected
459
460ms_post
461	Elapsed time for command post processing
462	(time from SCSI status get to command completion call)
463	Example above: 1.32 seconds spent for post processing
464
465Due to the 1/100 second tick of the system clock, "ms_post" time may
466be wrong.
467
468In the example above, we got 18038 interrupts "on the fly" and only
4691673 script breaks generally due to disconnections inside a segment
470of the scatter list.
471
472
4738. Control commands
474===================
475
476Control commands can be sent to the driver with write operations to
477the proc SCSI file system. The generic command syntax is the
478following::
479
480      echo "<verb> <parameters>" >/proc/scsi/ncr53c8xx/0
481      (assumes controller number is 0)
482
483Using "all" for "<target>" parameter with the commands below will
484apply to all targets of the SCSI chain (except the controller).
485
486Available commands:
487
4888.1 Set minimum synchronous period factor
489-----------------------------------------
490
491    setsync <target> <period factor>
492
493    :target:   target number
494    :period:   minimum synchronous period.
495               Maximum speed = 1000/(4*period factor) except for special
496               cases below.
497
498    Specify a period of 255, to force asynchronous transfer mode.
499
500      - 10 means 25 nano-seconds synchronous period
501      - 11 means 30 nano-seconds synchronous period
502      - 12 means 50 nano-seconds synchronous period
503
5048.2 Set wide size
505-----------------
506
507    setwide <target> <size>
508
509    :target:   target number
510    :size:     0=8 bits, 1=16bits
511
5128.3 Set maximum number of concurrent tagged commands
513----------------------------------------------------
514
515    settags <target> <tags>
516
517    :target:   target number
518    :tags:     number of concurrent tagged commands
519               must not be greater than SCSI_NCR_MAX_TAGS (default: 8)
520
5218.4 Set order type for tagged command
522-------------------------------------
523
524    setorder <order>
525
526    :order:    3 possible values:
527
528               simple:
529			use SIMPLE TAG for all operations (read and write)
530
531               ordered:
532			use ORDERED TAG for all operations
533
534               default:
535			use default tag type,
536                        SIMPLE  TAG for read  operations
537                        ORDERED TAG for write operations
538
539
5408.5 Set debug mode
541------------------
542
543    setdebug <list of debug flags>
544
545    Available debug flags:
546
547	======== ========================================================
548        alloc    print info about memory allocations (ccb, lcb)
549        queue    print info about insertions into the command start queue
550        result   print sense data on CHECK CONDITION status
551        scatter  print info about the scatter process
552        scripts  print info about the script binding process
553	tiny     print minimal debugging information
554	timing   print timing information of the NCR chip
555	nego     print information about SCSI negotiations
556	phase    print information on script interruptions
557	======== ========================================================
558
559    Use "setdebug" with no argument to reset debug flags.
560
561
5628.6 Clear profile counters
563--------------------------
564
565    clearprof
566
567    The profile counters are automatically cleared when the amount of
568    data transferred reaches 1000 GB in order to avoid overflow.
569    The "clearprof" command allows you to clear these counters at any time.
570
571
5728.7 Set flag (no_disc)
573----------------------
574
575    setflag <target> <flag>
576
577    target:    target number
578
579    For the moment, only one flag is available:
580
581        no_disc:   not allow target to disconnect.
582
583    Do not specify any flag in order to reset the flag. For example:
584
585    setflag 4
586      will reset no_disc flag for target 4, so will allow it disconnections.
587
588    setflag all
589      will allow disconnection for all devices on the SCSI bus.
590
591
5928.8 Set verbose level
593---------------------
594
595    setverbose #level
596
597    The driver default verbose level is 1. This command allows to change
598    th driver verbose level after boot-up.
599
6008.9 Reset all logical units of a target
601---------------------------------------
602
603    resetdev <target>
604
605    :target:   target number
606
607    The driver will try to send a BUS DEVICE RESET message to the target.
608    (Only supported by the SYM53C8XX driver and provided for test purpose)
609
6108.10 Abort all tasks of all logical units of a target
611-----------------------------------------------------
612
613    cleardev <target>
614
615    :target:   target number
616
617    The driver will try to send a ABORT message to all the logical units
618    of the target.
619
620    (Only supported by the SYM53C8XX driver and provided for test purpose)
621
622
6239. Configuration parameters
624===========================
625
626If the firmware of all your devices is perfect enough, all the
627features supported by the driver can be enabled at start-up.  However,
628if only one has a flaw for some SCSI feature, you can disable the
629support by the driver of this feature at linux start-up and enable
630this feature after boot-up only for devices that support it safely.
631
632CONFIG_SCSI_NCR53C8XX_IOMAPPED       (default answer: n)
633    Answer "y" if you suspect your mother board to not allow memory mapped I/O.
634
635    May slow down performance a little.  This option is required by
636    Linux/PPC and is used no matter what you select here.  Linux/PPC
637    suffers no performance loss with this option since all IO is memory
638    mapped anyway.
639
640CONFIG_SCSI_NCR53C8XX_DEFAULT_TAGS    (default answer: 8)
641    Default tagged command queue depth.
642
643CONFIG_SCSI_NCR53C8XX_MAX_TAGS         (default answer: 8)
644    This option allows you to specify the maximum number of tagged commands
645    that can be queued to a device. The maximum supported value is 32.
646
647CONFIG_SCSI_NCR53C8XX_SYNC            (default answer: 5)
648    This option allows you to specify the frequency in MHz the driver
649    will use at boot time for synchronous data transfer negotiations.
650    This frequency can be changed later with the "setsync" control command.
651    0 means "asynchronous data transfers".
652
653CONFIG_SCSI_NCR53C8XX_FORCE_SYNC_NEGO (default answer: n)
654    Force synchronous negotiation for all SCSI-2 devices.
655
656    Some SCSI-2 devices do not report this feature in byte 7 of inquiry
657    response but do support it properly (TAMARACK scanners for example).
658
659CONFIG_SCSI_NCR53C8XX_NO_DISCONNECT   (default and only reasonable answer: n)
660    If you suspect a device of yours does not properly support disconnections,
661    you can answer "y". Then, all SCSI devices will never disconnect the bus
662    even while performing long SCSI operations.
663
664CONFIG_SCSI_NCR53C8XX_SYMBIOS_COMPAT
665    Genuine SYMBIOS boards use GPIO0 in output for controller LED and GPIO3
666    bit as a flag indicating singled-ended/differential interface.
667    If all the boards of your system are genuine SYMBIOS boards or use
668    BIOS and drivers from SYMBIOS, you would want to enable this option.
669
670    This option must NOT be enabled if your system has at least one 53C8XX
671    based scsi board with a vendor-specific BIOS.
672    For example, Tekram DC-390/U, DC-390/W and DC-390/F scsi controllers
673    use a vendor-specific BIOS and are known to not use SYMBIOS compatible
674    GPIO wiring. So, this option must not be enabled if your system has
675    such a board installed.
676
677CONFIG_SCSI_NCR53C8XX_NVRAM_DETECT
678    Enable support for reading the serial NVRAM data on Symbios and
679    some Symbios compatible cards, and Tekram DC390W/U/F cards. Useful for
680    systems with more than one Symbios compatible controller where at least
681    one has a serial NVRAM, or for a system with a mixture of Symbios and
682    Tekram cards. Enables setting the boot order of host adaptors
683    to something other than the default order or "reverse probe" order.
684    Also enables Symbios and Tekram cards to be distinguished so
685    CONFIG_SCSI_NCR53C8XX_SYMBIOS_COMPAT may be set in a system with a
686    mixture of Symbios and Tekram cards so the Symbios cards can make use of
687    the full range of Symbios features, differential, led pin, without
688    causing problems for the Tekram card(s).
689
69010. Boot setup commands
691=======================
692
69310.1 Syntax
694-----------
695
696Setup commands can be passed to the driver either at boot time or as a
697string variable using 'insmod'.
698
699A boot setup command for the ncr53c8xx (sym53c8xx) driver begins with the
700driver name "ncr53c8xx="(sym53c8xx). The kernel syntax parser then expects
701an optional list of integers separated with comma followed by an optional
702list of comma-separated strings. Example of boot setup command under lilo
703prompt::
704
705    lilo: linux root=/dev/hda2 ncr53c8xx=tags:4,sync:10,debug:0x200
706
707- enable tagged commands, up to 4 tagged commands queued.
708- set synchronous negotiation speed to 10 Mega-transfers / second.
709- set DEBUG_NEGO flag.
710
711Since comma seems not to be allowed when defining a string variable using
712'insmod', the driver also accepts <space> as option separator.
713The following command will install driver module with the same options as
714above::
715
716    insmod ncr53c8xx.o ncr53c8xx="tags:4 sync:10 debug:0x200"
717
718For the moment, the integer list of arguments is discarded by the driver.
719It will be used in the future in order to allow a per controller setup.
720
721Each string argument must be specified as "keyword:value". Only lower-case
722characters and digits are allowed.
723
724In a system that contains multiple 53C8xx adapters insmod will install the
725specified driver on each adapter. To exclude a chip use the 'excl' keyword.
726
727The sequence of commands::
728
729    insmod sym53c8xx sym53c8xx=excl:0x1400
730    insmod ncr53c8xx
731
732installs the sym53c8xx driver on all adapters except the one at IO port
733address 0x1400 and then installs the ncr53c8xx driver to the adapter at IO
734port address 0x1400.
735
736
73710.2 Available arguments
738------------------------
739
74010.2.1  Master parity checking
741^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
742
743	======     ========
744        mpar:y     enabled
745        mpar:n     disabled
746	======     ========
747
74810.2.2  Scsi parity checking
749^^^^^^^^^^^^^^^^^^^^^^^^^^^^
750
751	======     ========
752        spar:y     enabled
753        spar:n     disabled
754	======     ========
755
75610.2.3  Scsi disconnections
757^^^^^^^^^^^^^^^^^^^^^^^^^^^
758
759	======     ========
760        disc:y     enabled
761        disc:n     disabled
762	======     ========
763
76410.2.4  Special features
765^^^^^^^^^^^^^^^^^^^^^^^^
766
767   Only apply to 810A, 825A, 860, 875 and 895 controllers.
768   Have no effect with other ones.
769
770	=======    =================================================
771        specf:y    (or 1) enabled
772        specf:n    (or 0) disabled
773        specf:3           enabled except Memory Write And Invalidate
774	=======    =================================================
775
776   The default driver setup is 'specf:3'. As a consequence, option 'specf:y'
777   must be specified in the boot setup command to enable Memory Write And
778   Invalidate.
779
78010.2.5  Ultra SCSI support
781^^^^^^^^^^^^^^^^^^^^^^^^^^
782
783   Only apply to 860, 875, 895, 895a, 896, 1010 and 1010_66 controllers.
784   Have no effect with other ones.
785
786	=======    ========================
787        ultra:n    All ultra speeds enabled
788        ultra:2    Ultra2 enabled
789        ultra:1    Ultra enabled
790        ultra:0    Ultra speeds disabled
791	=======    ========================
792
79310.2.6  Default number of tagged commands
794^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
795
796	======================= ===============================
797        tags:0     (or tags:1 ) tagged command queuing disabled
798        tags:#tags (#tags  > 1) tagged command queuing enabled
799	======================= ===============================
800
801  #tags will be truncated to the max queued commands configuration parameter.
802  This option also allows to specify a command queue depth for each device
803  that support tagged command queueing.
804
805  Example::
806
807      ncr53c8xx=tags:10/t2t3q16-t5q24/t1u2q32
808
809  will set devices queue depth as follow:
810
811      - controller #0 target #2 and target #3                  -> 16 commands,
812      - controller #0 target #5                                -> 24 commands,
813      - controller #1 target #1 logical unit #2                -> 32 commands,
814      - all other logical units (all targets, all controllers) -> 10 commands.
815
81610.2.7  Default synchronous period factor
817^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
818
819============ ========================================================
820sync:255     disabled (asynchronous transfer mode)
821sync:#factor
822	     ============     =======================================
823	     #factor = 10     Ultra-2 SCSI 40 Mega-transfers / second
824	     #factor = 11     Ultra-2 SCSI 33 Mega-transfers / second
825	     #factor < 25     Ultra   SCSI 20 Mega-transfers / second
826	     #factor < 50     Fast    SCSI-2
827	     ============     =======================================
828============ ========================================================
829
830  In all cases, the driver will use the minimum transfer period supported by
831  controllers according to NCR53C8XX chip type.
832
83310.2.8  Negotiate synchronous with all devices
834^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
835        (force sync nego)
836
837        =====      =========
838        fsn:y      enabled
839        fsn:n      disabled
840        =====      =========
841
84210.2.9  Verbosity level
843^^^^^^^^^^^^^^^^^^^^^^^
844
845        ======     =========
846        verb:0     minimal
847        verb:1     normal
848        verb:2     too much
849        ======     =========
850
85110.2.10 Debug mode
852^^^^^^^^^^^^^^^^^^
853
854========   ==================================================================
855debug:0    clear debug flags
856debug:#x   set debug flags
857
858	    #x is an integer value combining the following power-of-2 values:
859
860	    =============  ======
861	    DEBUG_ALLOC       0x1
862	    DEBUG_PHASE       0x2
863	    DEBUG_POLL        0x4
864	    DEBUG_QUEUE       0x8
865	    DEBUG_RESULT     0x10
866	    DEBUG_SCATTER    0x20
867	    DEBUG_SCRIPT     0x40
868	    DEBUG_TINY       0x80
869	    DEBUG_TIMING    0x100
870	    DEBUG_NEGO      0x200
871	    DEBUG_TAGS      0x400
872	    DEBUG_FREEZE    0x800
873	    DEBUG_RESTART  0x1000
874	    =============  ======
875========   ==================================================================
876
877  You can play safely with DEBUG_NEGO. However, some of these flags may
878  generate bunches of syslog messages.
879
88010.2.11 Burst max
881^^^^^^^^^^^^^^^^^
882
883=========  ==================================================================
884burst:0    burst disabled
885burst:255  get burst length from initial IO register settings.
886burst:#x   burst enabled (1<<#x burst transfers max)
887
888	   #x is an integer value which is log base 2 of the burst transfers
889	   max.
890
891	   The NCR53C875 and NCR53C825A support up to 128 burst transfers
892	   (#x = 7).
893
894	   Other chips only support up to 16 (#x = 4).
895
896	   This is a maximum value. The driver set the burst length according
897	   to chip and revision ids. By default the driver uses the maximum
898	   value supported by the chip.
899=========  ==================================================================
900
90110.2.12 LED support
902^^^^^^^^^^^^^^^^^^^
903
904        =====      ===================
905        led:1      enable  LED support
906        led:0      disable LED support
907        =====      ===================
908
909  Donnot enable LED support if your scsi board does not use SDMS BIOS.
910  (See 'Configuration parameters')
911
91210.2.13 Max wide
913^^^^^^^^^^^^^^^^
914
915        ======     ===================
916        wide:1      wide scsi enabled
917        wide:0      wide scsi disabled
918        ======     ===================
919
920  Some scsi boards use a 875 (ultra wide) and only supply narrow connectors.
921  If you have connected a wide device with a 50 pins to 68 pins cable
922  converter, any accepted wide negotiation will break further data transfers.
923  In such a case, using "wide:0" in the bootup command will be helpful.
924
92510.2.14 Differential mode
926^^^^^^^^^^^^^^^^^^^^^^^^^
927
928	======	=================================
929        diff:0	never set up diff mode
930        diff:1	set up diff mode if BIOS set it
931        diff:2	always set up diff mode
932        diff:3	set diff mode if GPIO3 is not set
933	======	=================================
934
93510.2.15 IRQ mode
936^^^^^^^^^^^^^^^^
937
938	=========  ========================================================
939        irqm:0     always open drain
940        irqm:1     same as initial settings (assumed BIOS settings)
941        irqm:2     always totem pole
942        irqm:0x10  driver will not use IRQF_SHARED flag when requesting irq
943	=========  ========================================================
944
945    (Bits 0x10 and 0x20 can be combined with hardware irq mode option)
946
94710.2.16 Reverse probe
948^^^^^^^^^^^^^^^^^^^^^
949
950	=========   ========================================================
951        revprob:n   probe chip ids from the PCI configuration in this order:
952                    810, 815, 820, 860, 875, 885, 895, 896
953        revprob:y   probe chip ids in the reverse order.
954	=========   ========================================================
955
95610.2.17 Fix up PCI configuration space
957^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
958        pcifix:<option bits>
959
960    Available option bits:
961
962	===    ===============================================================
963        0x0    No attempt to fix PCI configuration space registers values.
964        0x1    Set PCI cache-line size register if not set.
965        0x2    Set write and invalidate bit in PCI command register.
966        0x4    Increase if necessary PCI latency timer according to burst max.
967	===    ===============================================================
968
969    Use 'pcifix:7' in order to allow the driver to fix up all PCI features.
970
97110.2.18 Serial NVRAM
972^^^^^^^^^^^^^^^^^^^^
973
974	=======     =========================================
975        nvram:n     do not look for serial NVRAM
976        nvram:y     test controllers for onboard serial NVRAM
977	=======     =========================================
978
979        (alternate binary form)
980        mvram=<bits options>
981
982        ====   =================================================================
983        0x01   look for NVRAM  (equivalent to nvram=y)
984        0x02   ignore NVRAM "Synchronous negotiation" parameters for all devices
985        0x04   ignore NVRAM "Wide negotiation"  parameter for all devices
986        0x08   ignore NVRAM "Scan at boot time" parameter for all devices
987        0x80   also attach controllers set to OFF in the NVRAM (sym53c8xx only)
988        ====   =================================================================
989
99010.2.19 Check SCSI BUS
991^^^^^^^^^^^^^^^^^^^^^^
992
993        buschk:<option bits>
994
995    Available option bits:
996
997        ====   ================================================
998        0x0:   No check.
999        0x1:   Check and do not attach the controller on error.
1000        0x2:   Check and just warn on error.
1001        0x4:   Disable SCSI bus integrity checking.
1002        ====   ================================================
1003
100410.2.20 Exclude a host from being attached
1005^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1006
1007        excl=<io_address>
1008
1009    Prevent host at a given io address from being attached.
1010    For example 'ncr53c8xx=excl:0xb400,excl:0xc000' indicate to the
1011    ncr53c8xx driver not to attach hosts at address 0xb400 and 0xc000.
1012
101310.2.21 Suggest a default SCSI id for hosts
1014^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1015
1016	==========	==========================================
1017        hostid:255	no id suggested.
1018        hostid:#x	(0 < x < 7) x suggested for hosts SCSI id.
1019	==========	==========================================
1020
1021    If a host SCSI id is available from the NVRAM, the driver will ignore
1022    any value suggested as boot option. Otherwise, if a suggested value
1023    different from 255 has been supplied, it will use it. Otherwise, it will
1024    try to deduce the value previously set in the hardware and use value
1025    7 if the hardware value is zero.
1026
102710.2.22 Enable use of IMMEDIATE ARBITRATION
1028^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1029
1030        (only supported by the sym53c8xx driver. See 10.7 for more details)
1031
1032=======   =================================================================
1033iarb:0    do not use this feature.
1034iarb:#x   use this feature according to bit fields as follow:
1035
1036	  ========= =======================================================
1037	  bit 0 (1) enable IARB each time the initiator has been reselected
1038		    when it arbitrated for the SCSI BUS.
1039	  (#x >> 4) maximum number of successive settings of IARB if the
1040		    initiator win arbitration and it has other commands
1041		    to send to a device.
1042	  ========= =======================================================
1043=======   =================================================================
1044
1045Boot fail safe
1046    safe:y	load the following assumed fail safe initial setup
1047
1048  ========================	======================	==========
1049  master parity			disabled		mpar:n
1050  scsi parity			enabled			spar:y
1051  disconnections		not allowed		disc:n
1052  special features		disabled		specf:n
1053  ultra scsi			disabled		ultra:n
1054  force sync negotiation	disabled		fsn:n
1055  reverse probe			disabled		revprob:n
1056  PCI fix up                    disabled                pcifix:0
1057  serial NVRAM                  enabled                 nvram:y
1058  verbosity level		2			verb:2
1059  tagged command queuing	disabled		tags:0
1060  synchronous negotiation	disabled		sync:255
1061  debug flags			none			debug:0
1062  burst length			from BIOS settings	burst:255
1063  LED support			disabled		led:0
1064  wide support			disabled		wide:0
1065  settle time			10 seconds		settle:10
1066  differential support		from BIOS settings	diff:1
1067  irq mode			from BIOS settings	irqm:1
1068  SCSI BUS check		do not attach on error	buschk:1
1069  immediate arbitration		disabled		iarb:0
1070  ========================	======================	==========
1071
107210.3 Advised boot setup commands
1073^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1074
1075If the driver has been configured with default options, the equivalent
1076boot setup is::
1077
1078   ncr53c8xx=mpar:y,spar:y,disc:y,specf:3,fsn:n,ultra:2,fsn:n,revprob:n,verb:1\
1079             tags:0,sync:50,debug:0,burst:7,led:0,wide:1,settle:2,diff:0,irqm:0
1080
1081For an installation diskette or a safe but not fast system,
1082boot setup can be::
1083
1084    ncr53c8xx=safe:y,mpar:y,disc:y
1085    ncr53c8xx=safe:y,disc:y
1086    ncr53c8xx=safe:y,mpar:y
1087    ncr53c8xx=safe:y
1088
1089My personal system works flawlessly with the following equivalent setup::
1090
1091   ncr53c8xx=mpar:y,spar:y,disc:y,specf:1,fsn:n,ultra:2,fsn:n,revprob:n,verb:1\
1092             tags:32,sync:12,debug:0,burst:7,led:1,wide:1,settle:2,diff:0,irqm:0
1093
1094The driver prints its actual setup when verbosity level is 2. You can try
1095"ncr53c8xx=verb:2" to get the "static" setup of the driver, or add "verb:2"
1096to your boot setup command in order to check the actual setup the driver is
1097using.
1098
109910.4 PCI configuration fix-up boot option
1100-----------------------------------------
1101
1102pcifix:<option bits>
1103
1104Available option bits:
1105
1106    ===      =====================================================
1107    0x1      Set PCI cache-line size register if not set.
1108    0x2      Set write and invalidate bit in PCI command register.
1109    ===      =====================================================
1110
1111Use 'pcifix:3' in order to allow the driver to fix both PCI features.
1112
1113These options only apply to new SYMBIOS chips 810A, 825A, 860, 875
1114and 895 and are only supported for Pentium and 486 class processors.
1115Recent SYMBIOS 53C8XX scsi processors are able to use PCI read multiple
1116and PCI write and invalidate commands. These features require the
1117cache line size register to be properly set in the PCI configuration
1118space of the chips. On the other hand, chips will use PCI write and
1119invalidate commands only if the corresponding bit is set to 1 in the
1120PCI command register.
1121
1122Not all PCI bioses set the PCI cache line register and the PCI write and
1123invalidate bit in the PCI configuration space of 53C8XX chips.
1124Optimized PCI accesses may be broken for some PCI/memory controllers or
1125make problems with some PCI boards.
1126
1127This fix-up worked flawlessly on my previous system.
1128(MB Triton HX / 53C875 / 53C810A)
1129I use these options at my own risks as you will do if you decide to
1130use them too.
1131
1132
113310.5 Serial NVRAM support boot option
1134-------------------------------------
1135
1136=======     =========================================
1137nvram:n     do not look for serial NVRAM
1138nvram:y     test controllers for onboard serial NVRAM
1139=======     =========================================
1140
1141This option can also been entered as an hexadecimal value that allows
1142to control what information the driver will get from the NVRAM and what
1143information it will ignore.
1144For details see '17. Serial NVRAM support'.
1145
1146When this option is enabled, the driver tries to detect all boards using
1147a Serial NVRAM. This memory is used to hold user set up parameters.
1148
1149The parameters the driver is able to get from the NVRAM depend on the
1150data format used, as follow:
1151
1152+-------------------------------+------------------+--------------+
1153|                               |Tekram format     |Symbios format|
1154+-------------------------------+------------------+--------------+
1155|General and host parameters    |                  |              |
1156+-------------------------------+------------------+--------------+
1157|  * Boot order                 |        N         |       Y      |
1158+-------------------------------+------------------+--------------+
1159|  * Host SCSI ID               |        Y         |       Y      |
1160+-------------------------------+------------------+--------------+
1161|  * SCSI parity checking       |        Y         |       Y      |
1162+-------------------------------+------------------+--------------+
1163|  * Verbose boot messages      |        N         |       Y      |
1164+-------------------------------+------------------+--------------+
1165|SCSI devices parameters                                          |
1166+-------------------------------+------------------+--------------+
1167|  * Synchronous transfer speed |        Y         |       Y      |
1168+-------------------------------+------------------+--------------+
1169|  * Wide 16 / Narrow           |        Y         |       Y      |
1170+-------------------------------+------------------+--------------+
1171|  * Tagged Command Queuing     |        Y         |       Y      |
1172|    enabled                    |                  |              |
1173+-------------------------------+------------------+--------------+
1174|  * Disconnections enabled     |        Y         |       Y      |
1175+-------------------------------+------------------+--------------+
1176|  * Scan at boot time          |        N         |       Y      |
1177+-------------------------------+------------------+--------------+
1178
1179In order to speed up the system boot, for each device configured without
1180the "scan at boot time" option, the driver forces an error on the
1181first TEST UNIT READY command received for this device.
1182
1183Some SDMS BIOS revisions seem to be unable to boot cleanly with very fast
1184hard disks. In such a situation you cannot configure the NVRAM with
1185optimized parameters value.
1186
1187The 'nvram' boot option can be entered in hexadecimal form in order
1188to ignore some options configured in the NVRAM, as follow:
1189
1190mvram=<bits options>
1191
1192      ====   =================================================================
1193      0x01   look for NVRAM  (equivalent to nvram=y)
1194      0x02   ignore NVRAM "Synchronous negotiation" parameters for all devices
1195      0x04   ignore NVRAM "Wide negotiation"  parameter for all devices
1196      0x08   ignore NVRAM "Scan at boot time" parameter for all devices
1197      0x80   also attach controllers set to OFF in the NVRAM (sym53c8xx only)
1198      ====   =================================================================
1199
1200Option 0x80 is only supported by the sym53c8xx driver and is disabled by
1201default. Result is that, by default (option not set), the sym53c8xx driver
1202will not attach controllers set to OFF in the NVRAM.
1203
1204The ncr53c8xx always tries to attach all the controllers. Option 0x80 has
1205not been added to the ncr53c8xx driver, since it has been reported to
1206confuse users who use this driver since a long time. If you desire a
1207controller not to be attached by the ncr53c8xx driver at Linux boot, you
1208must use the 'excl' driver boot option.
1209
121010.6 SCSI BUS checking boot option.
1211^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1212
1213When this option is set to a non-zero value, the driver checks SCSI lines
1214logic state, 100 micro-seconds after having asserted the SCSI RESET line.
1215The driver just reads SCSI lines and checks all lines read FALSE except RESET.
1216Since SCSI devices shall release the BUS at most 800 nano-seconds after SCSI
1217RESET has been asserted, any signal to TRUE may indicate a SCSI BUS problem.
1218Unfortunately, the following common SCSI BUS problems are not detected:
1219
1220- Only 1 terminator installed.
1221- Misplaced terminators.
1222- Bad quality terminators.
1223
1224On the other hand, either bad cabling, broken devices, not conformant
1225devices, ... may cause a SCSI signal to be wrong when te driver reads it.
1226
122710.7 IMMEDIATE ARBITRATION boot option
1228^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1229
1230This option is only supported by the SYM53C8XX driver (not by the NCR53C8XX).
1231
1232SYMBIOS 53C8XX chips are able to arbitrate for the SCSI BUS as soon as they
1233have detected an expected disconnection (BUS FREE PHASE). For this process
1234to be started, bit 1 of SCNTL1 IO register must be set when the chip is
1235connected to the SCSI BUS.
1236
1237When this feature has been enabled for the current connection, the chip has
1238every chance to win arbitration if only devices with lower priority are
1239competing for the SCSI BUS. By the way, when the chip is using SCSI id 7,
1240then it will for sure win the next SCSI BUS arbitration.
1241
1242Since, there is no way to know what devices are trying to arbitrate for the
1243BUS, using this feature can be extremely unfair. So, you are not advised
1244to enable it, or at most enable this feature for the case the chip lost
1245the previous arbitration (boot option 'iarb:1').
1246
1247This feature has the following advantages:
1248
1249a) Allow the initiator with ID 7 to win arbitration when it wants so.
1250b) Overlap at least 4 micro-seconds of arbitration time with the execution
1251   of SCRIPTS that deal with the end of the current connection and that
1252   starts the next job.
1253
1254Hmmm... But (a) may just prevent other devices from reselecting the initiator,
1255and delay data transfers or status/completions, and (b) may just waste
1256SCSI BUS bandwidth if the SCRIPTS execution lasts more than 4 micro-seconds.
1257
1258The use of IARB needs the SCSI_NCR_IARB_SUPPORT option to have been defined
1259at compile time and the 'iarb' boot option to have been set to a non zero
1260value at boot time. It is not that useful for real work, but can be used
1261to stress SCSI devices or for some applications that can gain advantage of
1262it. By the way, if you experience badnesses like 'unexpected disconnections',
1263'bad reselections', etc... when using IARB on heavy IO load, you should not
1264be surprised, because force-feeding anything and blocking its arse at the
1265same time cannot work for a long time. :-))
1266
1267
126811. Some constants and flags of the ncr53c8xx.h header file
1269===========================================================
1270
1271Some of these are defined from the configuration parameters.  To
1272change other "defines", you must edit the header file.  Do that only
1273if you know what you are doing.
1274
1275SCSI_NCR_SETUP_SPECIAL_FEATURES	(default: defined)
1276	If defined, the driver will enable some special features according
1277	to chip and revision id.
1278
1279        For 810A, 860, 825A, 875 and 895 scsi chips, this option enables
1280	support of features that reduce load of PCI bus and memory accesses
1281	during  scsi transfer processing: burst op-code fetch, read multiple,
1282        read line, prefetch, cache line, write and invalidate,
1283        burst 128 (875 only), large dma fifo (875 only), offset 16 (875 only).
1284	Can be changed by the following boot setup command::
1285
1286		ncr53c8xx=specf:n
1287
1288SCSI_NCR_IOMAPPED		(default: not defined)
1289	If defined, normal I/O is forced.
1290
1291SCSI_NCR_SHARE_IRQ		(default: defined)
1292	If defined, request shared IRQ.
1293
1294SCSI_NCR_MAX_TAGS		(default: 8)
1295	Maximum number of simultaneous tagged commands to a device.
1296
1297	Can be changed by "settags <target> <maxtags>"
1298
1299SCSI_NCR_SETUP_DEFAULT_SYNC     (default: 50)
1300	Transfer period factor the driver will use at boot time for synchronous
1301	negotiation. 0 means asynchronous.
1302
1303	Can be changed by "setsync <target> <period factor>"
1304
1305SCSI_NCR_SETUP_DEFAULT_TAGS     (default: 8)
1306	Default number of simultaneous tagged commands to a device.
1307
1308	< 1 means tagged command queuing disabled at start-up.
1309
1310SCSI_NCR_ALWAYS_SIMPLE_TAG	(default: defined)
1311	Use SIMPLE TAG for read and write commands.
1312
1313	Can be changed by "setorder <ordered|simple|default>"
1314
1315SCSI_NCR_SETUP_DISCONNECTION	(default: defined)
1316	If defined, targets are allowed to disconnect.
1317
1318SCSI_NCR_SETUP_FORCE_SYNC_NEGO	(default: not defined)
1319	If defined, synchronous negotiation is tried for all SCSI-2 devices.
1320
1321	Can be changed by "setsync <target> <period>"
1322
1323SCSI_NCR_SETUP_MASTER_PARITY	(default: defined)
1324	If defined, master parity checking is enabled.
1325
1326SCSI_NCR_SETUP_SCSI_PARITY	(default: defined)
1327	If defined, SCSI parity checking is enabled.
1328
1329SCSI_NCR_PROFILE_SUPPORT	(default: not defined)
1330	If defined, profiling information is gathered.
1331
1332SCSI_NCR_MAX_SCATTER		(default: 128)
1333	Scatter list size of the driver ccb.
1334
1335SCSI_NCR_MAX_TARGET		(default: 16)
1336	Max number of targets per host.
1337
1338SCSI_NCR_MAX_HOST		(default: 2)
1339	Max number of host controllers.
1340
1341SCSI_NCR_SETTLE_TIME		(default: 2)
1342	Number of seconds the driver will wait after reset.
1343
1344SCSI_NCR_TIMEOUT_ALERT		(default: 3)
1345	If a pending command will time out after this amount of seconds,
1346	an ordered tag is used for the next command.
1347
1348	Avoids timeouts for unordered tagged commands.
1349
1350SCSI_NCR_CAN_QUEUE		(default: 7*SCSI_NCR_MAX_TAGS)
1351	Max number of commands that can be queued to a host.
1352
1353SCSI_NCR_CMD_PER_LUN		(default: SCSI_NCR_MAX_TAGS)
1354	Max number of commands queued to a host for a device.
1355
1356SCSI_NCR_SG_TABLESIZE		(default: SCSI_NCR_MAX_SCATTER-1)
1357	Max size of the Linux scatter/gather list.
1358
1359SCSI_NCR_MAX_LUN	(default: 8)
1360	Max number of LUNs per target.
1361
1362
136312. Installation
1364================
1365
1366This driver is part of the linux kernel distribution.
1367Driver files are located in the sub-directory "drivers/scsi" of the
1368kernel source tree.
1369
1370Driver files::
1371
1372	README.ncr53c8xx	: this file
1373	ChangeLog.ncr53c8xx	: change log
1374	ncr53c8xx.h		: definitions
1375	ncr53c8xx.c		: the driver code
1376
1377New driver versions are made available separately in order to allow testing
1378changes and new features prior to including them into the linux kernel
1379distribution. The following URL provides information on latest available
1380patches:
1381
1382      ftp://ftp.tux.org/pub/people/gerard-roudier/README
1383
1384
138513. Architecture dependent features
1386===================================
1387
1388<Not yet written>
1389
1390
139114. Known problems
1392==================
1393
139414.1 Tagged commands with Iomega Jaz device
1395-------------------------------------------
1396
1397I have not tried this device, however it has been reported to me the
1398following: This device is capable of Tagged command queuing. However
1399while spinning up, it rejects Tagged commands. This behaviour is
1400conforms to 6.8.2 of SCSI-2 specifications. The current behaviour of
1401the driver in that situation is not satisfying. So do not enable
1402Tagged command queuing for devices that are able to spin down.  The
1403other problem that may appear is timeouts. The only way to avoid
1404timeouts seems to edit linux/drivers/scsi/sd.c and to increase the
1405current timeout values.
1406
140714.2 Device names change when another controller is added
1408---------------------------------------------------------
1409
1410When you add a new NCR53C8XX chip based controller to a system that already
1411has one or more controllers of this family, it may happen that the order
1412the driver registers them to the kernel causes problems due to device
1413name changes.
1414When at least one controller uses NvRAM, SDMS BIOS version 4 allows you to
1415define the order the BIOS will scan the scsi boards. The driver attaches
1416controllers according to BIOS information if NvRAM detect option is set.
1417
1418If your controllers do not have NvRAM, you can:
1419
1420- Ask the driver to probe chip ids in reverse order from the boot command
1421  line: ncr53c8xx=revprob:y
1422- Make appropriate changes in the fstab.
1423- Use the 'scsidev' tool from Eric Youngdale.
1424
142514.3 Using only 8 bit devices with a WIDE SCSI controller
1426---------------------------------------------------------
1427
1428When only 8 bit NARROW devices are connected to a 16 bit WIDE SCSI controller,
1429you must ensure that lines of the wide part of the SCSI BUS are pulled-up.
1430This can be achieved by ENABLING the WIDE TERMINATOR portion of the SCSI
1431controller card.
1432
1433The TYAN 1365 documentation revision 1.2 is not correct about such settings.
1434(page 10, figure 3.3).
1435
143614.4 Possible data corruption during a Memory Write and Invalidate
1437------------------------------------------------------------------
1438
1439This problem is described in SYMBIOS DEL 397, Part Number 69-039241, ITEM 4.
1440
1441In some complex situations, 53C875 chips revision <= 3 may start a PCI
1442Write and Invalidate Command at a not cache-line-aligned 4 DWORDS boundary.
1443This is only possible when Cache Line Size is 8 DWORDS or greater.
1444Pentium systems use a 8 DWORDS cache line size and so are concerned by
1445this chip bug, unlike i486 systems that use a 4 DWORDS cache line size.
1446
1447When this situation occurs, the chip may complete the Write and Invalidate
1448command after having only filled part of the last cache line involved in
1449the transfer, leaving to data corruption the remainder of this cache line.
1450
1451Not using Write And Invalidate obviously gets rid of this chip bug, and so
1452it is now the default setting of the driver.
1453However, for people like me who want to enable this feature, I have added
1454part of a work-around suggested by SYMBIOS. This work-around resets the
1455addressing logic when the DATA IN phase is entered and so prevents the bug
1456from being triggered for the first SCSI MOVE of the phase. This work-around
1457should be enough according to the following:
1458
1459The only driver internal data structure that is greater than 8 DWORDS  and
1460that is moved by the SCRIPTS processor is the 'CCB header' that contains
1461the context of the SCSI transfer. This data structure is aligned on 8 DWORDS
1462boundary (Pentium Cache Line Size), and so is immune to this chip bug, at
1463least on Pentium systems.
1464
1465But the conditions of this bug can be met when a SCSI read command is
1466performed using a buffer that is 4 DWORDS but not cache-line aligned.
1467This cannot happen under Linux when scatter/gather lists are used since
1468they only refer to system buffers that are well aligned. So, a work around
1469may only be needed under Linux when a scatter/gather list is not used and
1470when the SCSI DATA IN phase is reentered after a phase mismatch.
1471
147215. SCSI problem troubleshooting
1473================================
1474
147515.1 Problem tracking
1476---------------------
1477
1478Most SCSI problems are due to a non conformant SCSI bus or to buggy
1479devices.  If unfortunately you have SCSI problems, you can check the
1480following things:
1481
1482- SCSI bus cables
1483- terminations at both end of the SCSI chain
1484- linux syslog messages (some of them may help you)
1485
1486If you do not find the source of problems, you can configure the
1487driver with no features enabled.
1488
1489- only asynchronous data transfers
1490- tagged commands disabled
1491- disconnections not allowed
1492
1493Now, if your SCSI bus is ok, your system have every chance to work
1494with this safe configuration but performances will not be optimal.
1495
1496If it still fails, then you can send your problem description to
1497appropriate mailing lists or news-groups.  Send me a copy in order to
1498be sure I will receive it.  Obviously, a bug in the driver code is
1499possible.
1500
1501     My email address: Gerard Roudier <groudier@free.fr>
1502
1503Allowing disconnections is important if you use several devices on
1504your SCSI bus but often causes problems with buggy devices.
1505Synchronous data transfers increases throughput of fast devices like
1506hard disks.  Good SCSI hard disks with a large cache gain advantage of
1507tagged commands queuing.
1508
1509Try to enable one feature at a time with control commands.  For example:
1510
1511::
1512
1513    echo "setsync all 25" >/proc/scsi/ncr53c8xx/0
1514
1515Will enable fast synchronous data transfer negotiation for all targets.
1516
1517::
1518
1519    echo "setflag 3" >/proc/scsi/ncr53c8xx/0
1520
1521Will reset flags (no_disc) for target 3, and so will allow it to disconnect
1522the SCSI Bus.
1523
1524::
1525
1526    echo "settags 3 8" >/proc/scsi/ncr53c8xx/0
1527
1528Will enable tagged command queuing for target 3 if that device supports it.
1529
1530Once you have found the device and the feature that cause problems, just
1531disable that feature for that device.
1532
153315.2 Understanding hardware error reports
1534-----------------------------------------
1535
1536When the driver detects an unexpected error condition, it may display a
1537message of the following pattern::
1538
1539    sym53c876-0:1: ERROR (0:48) (1-21-65) (f/95) @ (script 7c0:19000000).
1540    sym53c876-0: script cmd = 19000000
1541    sym53c876-0: regdump: da 10 80 95 47 0f 01 07 75 01 81 21 80 01 09 00.
1542
1543Some fields in such a message may help you understand the cause of the
1544problem, as follows::
1545
1546    sym53c876-0:1: ERROR (0:48) (1-21-65) (f/95) @ (script 7c0:19000000).
1547    ............A.........B.C....D.E..F....G.H.......I.....J...K.......
1548
1549Field A : target number.
1550  SCSI ID of the device the controller was talking with at the moment the
1551  error occurs.
1552
1553Field B : DSTAT io register (DMA STATUS)
1554  ========   =============================================================
1555  Bit 0x40   MDPE Master Data Parity Error
1556             Data parity error detected on the PCI BUS.
1557  Bit 0x20   BF   Bus Fault
1558             PCI bus fault condition detected
1559  Bit 0x01   IID  Illegal Instruction Detected
1560             Set by the chip when it detects an Illegal Instruction format
1561             on some condition that makes an instruction illegal.
1562  Bit 0x80   DFE Dma Fifo Empty
1563             Pure status bit that does not indicate an error.
1564  ========   =============================================================
1565
1566  If the reported DSTAT value contains a combination of MDPE (0x40),
1567  BF (0x20), then the cause may be likely due to a PCI BUS problem.
1568
1569Field C : SIST io register (SCSI Interrupt Status)
1570  ========   ==================================================================
1571  Bit 0x08   SGE  SCSI GROSS ERROR
1572             Indicates that the chip detected a severe error condition
1573             on the SCSI BUS that prevents the SCSI protocol from functioning
1574             properly.
1575  Bit 0x04   UDC  Unexpected Disconnection
1576             Indicates that the device released the SCSI BUS when the chip
1577             was not expecting this to happen. A device may behave so to
1578             indicate the SCSI initiator that an error condition not reportable
1579             using the SCSI protocol has occurred.
1580  Bit 0x02   RST  SCSI BUS Reset
1581             Generally SCSI targets do not reset the SCSI BUS, although any
1582             device on the BUS can reset it at any time.
1583  Bit 0x01   PAR  Parity
1584             SCSI parity error detected.
1585  ========   ==================================================================
1586
1587  On a faulty SCSI BUS, any error condition among SGE (0x08), UDC (0x04) and
1588  PAR (0x01) may be detected by the chip. If your SCSI system sometimes
1589  encounters such error conditions, especially SCSI GROSS ERROR, then a SCSI
1590  BUS problem is likely the cause of these errors.
1591
1592For fields D,E,F,G and H, you may look into the sym53c8xx_defs.h file
1593that contains some minimal comments on IO register bits.
1594
1595Field D : SOCL  Scsi Output Control Latch
1596          This register reflects the state of the SCSI control lines the
1597          chip want to drive or compare against.
1598
1599Field E : SBCL  Scsi Bus Control Lines
1600          Actual value of control lines on the SCSI BUS.
1601
1602Field F : SBDL  Scsi Bus Data Lines
1603          Actual value of data lines on the SCSI BUS.
1604
1605Field G : SXFER  SCSI Transfer
1606          Contains the setting of the Synchronous Period for output and
1607          the current Synchronous offset (offset 0 means asynchronous).
1608
1609Field H : SCNTL3 Scsi Control Register 3
1610          Contains the setting of timing values for both asynchronous and
1611          synchronous data transfers.
1612
1613Understanding Fields I, J, K and dumps requires to have good knowledge of
1614SCSI standards, chip cores functionnals and internal driver data structures.
1615You are not required to decode and understand them, unless you want to help
1616maintain the driver code.
1617
161816. Synchronous transfer negotiation tables
1619===========================================
1620
1621Tables below have been created by calling the routine the driver uses
1622for synchronisation negotiation timing calculation and chip setting.
1623The first table corresponds to Ultra chips 53875 and 53C860 with 80 MHz
1624clock and 5 clock divisors.
1625The second one has been calculated by setting the scsi clock to 40 Mhz
1626and using 4 clock divisors and so applies to all NCR53C8XX chips in fast
1627SCSI-2 mode.
1628
1629Periods are in nano-seconds and speeds are in Mega-transfers per second.
16301 Mega-transfers/second means 1 MB/s with 8 bits SCSI and 2 MB/s with
1631Wide16 SCSI.
1632
163316.1 Synchronous timings for 53C895, 53C875 and 53C860 SCSI controllers
1634
1635+-----------------------------+--------+-------+--------------+
1636|Negotiated                   |NCR settings    |              |
1637+-------+--------+------------+--------+-------+              |
1638|Factor |Period  |Speed       |Period  |Speed  |              |
1639+-------+--------+------------+--------+-------+--------------+
1640|10     | 25     |40.000      | 25     |40.000 | (53C895 only)|
1641+-------+--------+------------+--------+-------+--------------+
1642|11     | 30.2   |33.112      | 31.25  |32.000 | (53C895 only)|
1643+-------+--------+------------+--------+-------+--------------+
1644|12     | 50     |20.000      | 50     |20.000 |              |
1645+-------+--------+------------+--------+-------+--------------+
1646|13     | 52     |19.230      | 62     |16.000 |              |
1647+-------+--------+------------+--------+-------+--------------+
1648|14     | 56     |17.857      | 62     |16.000 |              |
1649+-------+--------+------------+--------+-------+--------------+
1650|15     | 60     |16.666      | 62     |16.000 |              |
1651+-------+--------+------------+--------+-------+--------------+
1652|16     | 64     |15.625      | 75     |13.333 |              |
1653+-------+--------+------------+--------+-------+--------------+
1654|17     | 68     |14.705      | 75     |13.333 |              |
1655+-------+--------+------------+--------+-------+--------------+
1656|18     | 72     |13.888      | 75     |13.333 |              |
1657+-------+--------+------------+--------+-------+--------------+
1658|19     | 76     |13.157      | 87     |11.428 |              |
1659+-------+--------+------------+--------+-------+--------------+
1660|20     | 80     |12.500      | 87     |11.428 |              |
1661+-------+--------+------------+--------+-------+--------------+
1662|21     | 84     |11.904      | 87     |11.428 |              |
1663+-------+--------+------------+--------+-------+--------------+
1664|22     | 88     |11.363      | 93     |10.666 |              |
1665+-------+--------+------------+--------+-------+--------------+
1666|23     | 92     |10.869      | 93     |10.666 |              |
1667+-------+--------+------------+--------+-------+--------------+
1668|24     | 96     |10.416      |100     |10.000 |              |
1669+-------+--------+------------+--------+-------+--------------+
1670|25     |100     |10.000      |100     |10.000 |              |
1671+-------+--------+------------+--------+-------+--------------+
1672|26     |104     | 9.615      |112     | 8.888 |              |
1673+-------+--------+------------+--------+-------+--------------+
1674|27     |108     | 9.259      |112     | 8.888 |              |
1675+-------+--------+------------+--------+-------+--------------+
1676|28     |112     | 8.928      |112     | 8.888 |              |
1677+-------+--------+------------+--------+-------+--------------+
1678|29     |116     | 8.620      |125     | 8.000 |              |
1679+-------+--------+------------+--------+-------+--------------+
1680|30     |120     | 8.333      |125     | 8.000 |              |
1681+-------+--------+------------+--------+-------+--------------+
1682|31     |124     | 8.064      |125     | 8.000 |              |
1683+-------+--------+------------+--------+-------+--------------+
1684|32     |128     | 7.812      |131     | 7.619 |              |
1685+-------+--------+------------+--------+-------+--------------+
1686|33     |132     | 7.575      |150     | 6.666 |              |
1687+-------+--------+------------+--------+-------+--------------+
1688|34     |136     | 7.352      |150     | 6.666 |              |
1689+-------+--------+------------+--------+-------+--------------+
1690|35     |140     | 7.142      |150     | 6.666 |              |
1691+-------+--------+------------+--------+-------+--------------+
1692|36     |144     | 6.944      |150     | 6.666 |              |
1693+-------+--------+------------+--------+-------+--------------+
1694|37     |148     | 6.756      |150     | 6.666 |              |
1695+-------+--------+------------+--------+-------+--------------+
1696|38     |152     | 6.578      |175     | 5.714 |              |
1697+-------+--------+------------+--------+-------+--------------+
1698|39     |156     | 6.410      |175     | 5.714 |              |
1699+-------+--------+------------+--------+-------+--------------+
1700|40     |160     | 6.250      |175     | 5.714 |              |
1701+-------+--------+------------+--------+-------+--------------+
1702|41     |164     | 6.097      |175     | 5.714 |              |
1703+-------+--------+------------+--------+-------+--------------+
1704|42     |168     | 5.952      |175     | 5.714 |              |
1705+-------+--------+------------+--------+-------+--------------+
1706|43     |172     | 5.813      |175     | 5.714 |              |
1707+-------+--------+------------+--------+-------+--------------+
1708|44     |176     | 5.681      |187     | 5.333 |              |
1709+-------+--------+------------+--------+-------+--------------+
1710|45     |180     | 5.555      |187     | 5.333 |              |
1711+-------+--------+------------+--------+-------+--------------+
1712|46     |184     | 5.434      |187     | 5.333 |              |
1713+-------+--------+------------+--------+-------+--------------+
1714|47     |188     | 5.319      |200     | 5.000 |              |
1715+-------+--------+------------+--------+-------+--------------+
1716|48     |192     | 5.208      |200     | 5.000 |              |
1717+-------+--------+------------+--------+-------+--------------+
1718|49     |196     | 5.102      |200     | 5.000 |              |
1719+-------+--------+------------+--------+-------+--------------+
1720
172116.2 Synchronous timings for fast SCSI-2 53C8XX controllers
1722
1723+-----------------------------+----------------+
1724|Negotiated                   |NCR settings    |
1725+-------+--------+------------+--------+-------+
1726|Factor |Period  |Speed       |Period  |Speed  |
1727+-------+--------+------------+--------+-------+
1728|25     |100     |10.000      |100     |10.000 |
1729+-------+--------+------------+--------+-------+
1730|26     |104     |9.615       |125     | 8.000 |
1731+-------+--------+------------+--------+-------+
1732|27     |108     |9.259       |125     | 8.000 |
1733+-------+--------+------------+--------+-------+
1734|28     |112     |8.928       |125     | 8.000 |
1735+-------+--------+------------+--------+-------+
1736|29     |116     |8.620       |125     | 8.000 |
1737+-------+--------+------------+--------+-------+
1738|30     |120     |8.333       |125     | 8.000 |
1739+-------+--------+------------+--------+-------+
1740|31     |124     |8.064       |125     | 8.000 |
1741+-------+--------+------------+--------+-------+
1742|32     |128     |7.812       |131     | 7.619 |
1743+-------+--------+------------+--------+-------+
1744|33     |132     |7.575       |150     | 6.666 |
1745+-------+--------+------------+--------+-------+
1746|34     |136     |7.352       |150     | 6.666 |
1747+-------+--------+------------+--------+-------+
1748|35     |140     |7.142       |150     | 6.666 |
1749+-------+--------+------------+--------+-------+
1750|36     |144     |6.944       |150     | 6.666 |
1751+-------+--------+------------+--------+-------+
1752|37     |148     |6.756       |150     | 6.666 |
1753+-------+--------+------------+--------+-------+
1754|38     |152     |6.578       |175     | 5.714 |
1755+-------+--------+------------+--------+-------+
1756|39     |156     |6.410       |175     | 5.714 |
1757+-------+--------+------------+--------+-------+
1758|40     |160     |6.250       |175     | 5.714 |
1759+-------+--------+------------+--------+-------+
1760|41     |164     |6.097       |175     | 5.714 |
1761+-------+--------+------------+--------+-------+
1762|42     |168     |5.952       |175     | 5.714 |
1763+-------+--------+------------+--------+-------+
1764|43     |172     |5.813       |175     | 5.714 |
1765+-------+--------+------------+--------+-------+
1766|44     |176     |5.681       |187     | 5.333 |
1767+-------+--------+------------+--------+-------+
1768|45     |180     |5.555       |187     | 5.333 |
1769+-------+--------+------------+--------+-------+
1770|46     |184     |5.434       |187     | 5.333 |
1771+-------+--------+------------+--------+-------+
1772|47     |188     |5.319       |200     | 5.000 |
1773+-------+--------+------------+--------+-------+
1774|48     |192     |5.208       |200     | 5.000 |
1775+-------+--------+------------+--------+-------+
1776|49     |196     |5.102       |200     | 5.000 |
1777+-------+--------+------------+--------+-------+
1778
1779
178017. Serial NVRAM
1781================
1782
1783(added by Richard Waltham: dormouse@farsrobt.demon.co.uk)
1784
178517.1 Features
1786-------------
1787
1788Enabling serial NVRAM support enables detection of the serial NVRAM included
1789on Symbios and some Symbios compatible host adaptors, and Tekram boards. The
1790serial NVRAM is used by Symbios and Tekram to hold set up parameters for the
1791host adaptor and its attached drives.
1792
1793The Symbios NVRAM also holds data on the boot order of host adaptors in a
1794system with more than one host adaptor. This enables the order of scanning
1795the cards for drives to be changed from the default used during host adaptor
1796detection.
1797
1798This can be done to a limited extent at the moment using "reverse probe" but
1799this only changes the order of detection of different types of cards. The
1800NVRAM boot order settings can do this as well as change the order the same
1801types of cards are scanned in, something "reverse probe" cannot do.
1802
1803Tekram boards using Symbios chips, DC390W/F/U, which have NVRAM are detected
1804and this is used to distinguish between Symbios compatible and Tekram host
1805adaptors. This is used to disable the Symbios compatible "diff" setting
1806incorrectly set on Tekram boards if the CONFIG_SCSI_53C8XX_SYMBIOS_COMPAT
1807configuration parameter is set enabling both Symbios and Tekram boards to be
1808used together with the Symbios cards using all their features, including
1809"diff" support. ("led pin" support for Symbios compatible cards can remain
1810enabled when using Tekram cards. It does nothing useful for Tekram host
1811adaptors but does not cause problems either.)
1812
1813
181417.2 Symbios NVRAM layout
1815-------------------------
1816
1817typical data at NVRAM address 0x100 (53c810a NVRAM)::
1818
1819    00 00
1820    64 01
1821    8e 0b
1822
1823    00 30 00 00 00 00 07 00 00 00 00 00 00 00 07 04 10 04 00 00
1824
1825    04 00 0f 00 00 10 00 50 00 00 01 00 00 62
1826    04 00 03 00 00 10 00 58 00 00 01 00 00 63
1827    04 00 01 00 00 10 00 48 00 00 01 00 00 61
1828    00 00 00 00 00 00 00 00 00 00 00 00 00 00
1829
1830    0f 00 08 08 64 00 0a 00
1831    0f 00 08 08 64 00 0a 00
1832    0f 00 08 08 64 00 0a 00
1833    0f 00 08 08 64 00 0a 00
1834    0f 00 08 08 64 00 0a 00
1835    0f 00 08 08 64 00 0a 00
1836    0f 00 08 08 64 00 0a 00
1837    0f 00 08 08 64 00 0a 00
1838
1839    0f 00 08 08 64 00 0a 00
1840    0f 00 08 08 64 00 0a 00
1841    0f 00 08 08 64 00 0a 00
1842    0f 00 08 08 64 00 0a 00
1843    0f 00 08 08 64 00 0a 00
1844    0f 00 08 08 64 00 0a 00
1845    0f 00 08 08 64 00 0a 00
1846    0f 00 08 08 64 00 0a 00
1847
1848    00 00 00 00 00 00 00 00
1849    00 00 00 00 00 00 00 00
1850    00 00 00 00 00 00 00 00
1851    00 00 00 00 00 00 00 00
1852    00 00 00 00 00 00 00 00
1853    00 00 00 00 00 00 00 00
1854    00 00 00 00 00 00 00 00
1855    00 00 00 00 00 00 00 00
1856
1857    00 00 00 00 00 00 00 00
1858    00 00 00 00 00 00 00 00
1859    00 00 00 00 00 00 00 00
1860    00 00 00 00 00 00 00 00
1861    00 00 00 00 00 00 00 00
1862    00 00 00 00 00 00 00 00
1863    00 00 00 00 00 00 00 00
1864    00 00 00 00 00 00 00 00
1865
1866    00 00 00 00 00 00 00 00
1867    00 00 00 00 00 00 00 00
1868    00 00 00 00 00 00 00 00
1869
1870    fe fe
1871    00 00
1872    00 00
1873
1874NVRAM layout details
1875
1876=============  ================
1877NVRAM Address
1878=============  ================
18790x000-0x0ff    not used
18800x100-0x26f    initialised data
18810x270-0x7ff    not used
1882=============  ================
1883
1884general layout::
1885
1886        header  -   6 bytes,
1887        data    - 356 bytes (checksum is byte sum of this data)
1888        trailer -   6 bytes
1889                  ---
1890        total     368 bytes
1891
1892data area layout::
1893
1894        controller set up  -  20 bytes
1895        boot configuration -  56 bytes (4x14 bytes)
1896        device set up      - 128 bytes (16x8 bytes)
1897        unused (spare?)    - 152 bytes (19x8 bytes)
1898                             ---
1899        total                356 bytes
1900
1901header::
1902
1903    00 00   - ?? start marker
1904    64 01   - byte count (lsb/msb excludes header/trailer)
1905    8e 0b   - checksum (lsb/msb excludes header/trailer)
1906
1907controller set up::
1908
1909    00 30 00 00 00 00 07 00 00 00 00 00 00 00 07 04 10 04 00 00
1910		    |     |           |     |
1911		    |     |           |      -- host ID
1912		    |     |           |
1913		    |     |            --Removable Media Support
1914		    |     |               0x00 = none
1915		    |     |               0x01 = Bootable Device
1916		    |     |               0x02 = All with Media
1917		    |     |
1918		    |      --flag bits 2
1919		    |        0x00000001= scan order hi->low
1920		    |            (default 0x00 - scan low->hi)
1921			--flag bits 1
1922			0x00000001 scam enable
1923			0x00000010 parity enable
1924			0x00000100 verbose boot msgs
1925
1926remaining bytes unknown - they do not appear to change in my
1927current set up for any of the controllers.
1928
1929default set up is identical for 53c810a and 53c875 NVRAM
1930(Removable Media added Symbios BIOS version 4.09)
1931
1932boot configuration
1933
1934boot order set by order of the devices in this table::
1935
1936    04 00 0f 00 00 10 00 50 00 00 01 00 00 62 -- 1st controller
1937    04 00 03 00 00 10 00 58 00 00 01 00 00 63    2nd controller
1938    04 00 01 00 00 10 00 48 00 00 01 00 00 61    3rd controller
1939    00 00 00 00 00 00 00 00 00 00 00 00 00 00    4th controller
1940	|  |  |  |     |        |     |  |
1941	|  |  |  |     |        |      ---- PCI io port adr
1942	|  |  |  |     |         --0x01 init/scan at boot time
1943	|  |  |  |      --PCI device/function number (0xdddddfff)
1944	|  |   ----- ?? PCI vendor ID (lsb/msb)
1945	    ----PCI device ID (lsb/msb)
1946
1947    ?? use of this data is a guess but seems reasonable
1948
1949remaining bytes unknown - they do not appear to change in my
1950current set up
1951
1952default set up is identical for 53c810a and 53c875 NVRAM
1953--------------------------------------------------------
1954
1955device set up (up to 16 devices - includes controller)::
1956
1957    0f 00 08 08 64 00 0a 00 - id 0
1958    0f 00 08 08 64 00 0a 00
1959    0f 00 08 08 64 00 0a 00
1960    0f 00 08 08 64 00 0a 00
1961    0f 00 08 08 64 00 0a 00
1962    0f 00 08 08 64 00 0a 00
1963    0f 00 08 08 64 00 0a 00
1964    0f 00 08 08 64 00 0a 00
1965
1966    0f 00 08 08 64 00 0a 00
1967    0f 00 08 08 64 00 0a 00
1968    0f 00 08 08 64 00 0a 00
1969    0f 00 08 08 64 00 0a 00
1970    0f 00 08 08 64 00 0a 00
1971    0f 00 08 08 64 00 0a 00
1972    0f 00 08 08 64 00 0a 00
1973    0f 00 08 08 64 00 0a 00 - id 15
1974    |     |  |  |     |  |
1975    |     |  |  |      ----timeout (lsb/msb)
1976    |     |  |   --synch period (0x?? 40 Mtrans/sec- fast 40) (probably 0x28)
1977    |     |  |                  (0x30 20 Mtrans/sec- fast 20)
1978    |     |  |                  (0x64 10 Mtrans/sec- fast )
1979    |     |  |                  (0xc8  5 Mtrans/sec)
1980    |     |  |                  (0x00  asynchronous)
1981    |     |   -- ?? max sync offset (0x08 in NVRAM on 53c810a)
1982    |     |                         (0x10 in NVRAM on 53c875)
1983    |      --device bus width (0x08 narrow)
1984    |                         (0x10 16 bit wide)
1985    --flag bits
1986	0x00000001 - disconnect enabled
1987	0x00000010 - scan at boot time
1988	0x00000100 - scan luns
1989	0x00001000 - queue tags enabled
1990
1991remaining bytes unknown - they do not appear to change in my
1992current set up
1993
1994?? use of this data is a guess but seems reasonable
1995(but it could be max bus width)
1996
1997default set up for 53c810a NVRAM
1998default set up for 53c875 NVRAM
1999
2000				- bus width     - 0x10
2001                                - sync offset ? - 0x10
2002                                - sync period   - 0x30
2003
2004?? spare device space (32 bit bus ??)
2005
2006::
2007
2008    00 00 00 00 00 00 00 00  (19x8bytes)
2009    .
2010    .
2011    00 00 00 00 00 00 00 00
2012
2013default set up is identical for 53c810a and 53c875 NVRAM
2014--------------------------------------------------------
2015
2016trailer::
2017
2018    fe fe   - ? end marker ?
2019    00 00
2020    00 00
2021
2022default set up is identical for 53c810a and 53c875 NVRAM
2023-----------------------------------------------------------
2024
2025
2026
202717.3 Tekram NVRAM layout
2028------------------------
2029
2030nvram 64x16 (1024 bit)
2031
2032Drive settings::
2033
2034    Drive ID 0-15 (addr 0x0yyyy0 = device setup, yyyy = ID)
2035		(addr 0x0yyyy1 = 0x0000)
2036
2037	x x x x  x x x x  x x x x  x x x x
2038		| | |      | |  | | | |
2039		| | |      | |  | | |  ----- parity check   0 - off
2040		| | |      | |  | | |                       1 - on
2041		| | |      | |  | | |
2042		| | |      | |  | |  ------- sync neg       0 - off
2043		| | |      | |  | |                         1 - on
2044		| | |      | |  | |
2045		| | |      | |  |  --------- disconnect     0 - off
2046		| | |      | |  |                           1 - on
2047		| | |      | |  |
2048		| | |      | |   ----------- start cmd      0 - off
2049		| | |      | |                              1 - on
2050		| | |      | |
2051		| | |      |  -------------- tagged cmds    0 - off
2052		| | |      |                                1 - on
2053		| | |      |
2054		| | |       ---------------- wide neg       0 - off
2055		| | |                                       1 - on
2056		| | |
2057		    --------------------------- sync rate      0 - 10.0 Mtrans/sec
2058							    1 -  8.0
2059							    2 -  6.6
2060							    3 -  5.7
2061							    4 -  5.0
2062							    5 -  4.0
2063							    6 -  3.0
2064							    7 -  2.0
2065							    7 -  2.0
2066							    8 - 20.0
2067							    9 - 16.7
2068							    a - 13.9
2069							    b - 11.9
2070
2071Global settings
2072
2073Host flags 0 (addr 0x100000, 32)::
2074
2075    x x x x  x x x x  x x x x  x x x x
2076    | | | |  | | | |           | | | |
2077    | | | |  | | | |            ----------- host ID    0x00 - 0x0f
2078    | | | |  | | | |
2079    | | | |  | | |  ----------------------- support for    0 - off
2080    | | | |  | | |                          > 2 drives     1 - on
2081    | | | |  | | |
2082    | | | |  | |  ------------------------- support drives 0 - off
2083    | | | |  | |                            > 1Gbytes      1 - on
2084    | | | |  | |
2085    | | | |  |  --------------------------- bus reset on   0 - off
2086    | | | |  |                                power on     1 - on
2087    | | | |  |
2088    | | | |   ----------------------------- active neg     0 - off
2089    | | | |                                                1 - on
2090    | | | |
2091    | | |  -------------------------------- imm seek       0 - off
2092    | | |                                                  1 - on
2093    | | |
2094    | |  ---------------------------------- scan luns      0 - off
2095    | |                                                    1 - on
2096    | |
2097     -------------------------------------- removable      0 - disable
2098                                            as BIOS dev    1 - boot device
2099                                                           2 - all
2100
2101Host flags 1 (addr 0x100001, 33)::
2102
2103    x x x x  x x x x  x x x x  x x x x
2104               | | |             | | |
2105               | | |              --------- boot delay     0 -   3 sec
2106               | | |                                       1 -   5
2107               | | |                                       2 -  10
2108               | | |                                       3 -  20
2109               | | |                                       4 -  30
2110               | | |                                       5 -  60
2111               | | |                                       6 - 120
2112               | | |
2113                --------------------------- max tag cmds   0 -  2
2114                                                           1 -  4
2115                                                           2 -  8
2116                                                           3 - 16
2117                                                           4 - 32
2118
2119Host flags 2 (addr 0x100010, 34)::
2120
2121    x x x x  x x x x  x x x x  x x x x
2122                                     |
2123                                      ----- F2/F6 enable   0 - off ???
2124                                                           1 - on  ???
2125
2126checksum (addr 0x111111)
2127
2128checksum = 0x1234 - (sum addr 0-63)
2129
2130----------------------------------------------------------------------------
2131
2132default nvram data::
2133
2134    0x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
2135    0x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
2136    0x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
2137    0x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
2138
2139    0x0f07 0x0400 0x0001 0x0000 0x0000 0x0000 0x0000 0x0000
2140    0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000
2141    0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000
2142    0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0xfbbc
2143
2144
214518. Support for Big Endian
2146==========================
2147
2148The PCI local bus has been primarily designed for x86 architecture.
2149As a consequence, PCI devices generally expect DWORDS using little endian
2150byte ordering.
2151
215218.1 Big Endian CPU
2153-------------------
2154
2155In order to support NCR chips on a Big Endian architecture the driver has to
2156perform byte reordering each time it is needed. This feature has been
2157added to the driver by Cort <cort@cs.nmt.edu> and is available in driver
2158version 2.5 and later ones. For the moment Big Endian support has only
2159been tested on Linux/PPC (PowerPC).
2160
216118.2 NCR chip in Big Endian mode of operations
2162----------------------------------------------
2163
2164It can be read in SYMBIOS documentation that some chips support a special
2165Big Endian mode, on paper: 53C815, 53C825A, 53C875, 53C875N, 53C895.
2166This mode of operations is not software-selectable, but needs pin named
2167BigLit to be pulled-up. Using this mode, most of byte reorderings should
2168be avoided when the driver is running on a Big Endian CPU.
2169Driver version 2.5 is also, in theory, ready for this feature.
2170