1.. SPDX-License-Identifier: GPL-2.0
2
3=========================================
4The Linux SYM-2 driver documentation file
5=========================================
6
7Written by Gerard Roudier <groudier@free.fr>
8
921 Rue Carnot
10
1195170 DEUIL LA BARRE - FRANCE
12
13Updated by Matthew Wilcox <matthew@wil.cx>
14
152004-10-09
16
17.. Contents
18
19   1.  Introduction
20   2.  Supported chips and SCSI features
21   3.  Advantages of this driver for newer chips.
22         3.1 Optimized SCSI SCRIPTS
23         3.2 New features appeared with the SYM53C896
24   4.  Memory mapped I/O versus normal I/O
25   5.  Tagged command queueing
26   6.  Parity checking
27   7.  Profiling information
28   8.  Control commands
29         8.1  Set minimum synchronous period
30         8.2  Set wide size
31         8.3  Set maximum number of concurrent tagged commands
32         8.4  Set debug mode
33         8.5  Set flag (no_disc)
34         8.6  Set verbose level
35         8.7  Reset all logical units of a target
36         8.8  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  Default number of tagged commands
42                10.2.2  Burst max
43                10.2.3  LED support
44                10.2.4  Differential mode
45                10.2.5  IRQ mode
46                10.2.6  Check SCSI BUS
47                10.2.7  Suggest a default SCSI id for hosts
48                10.2.8  Verbosity level
49                10.2.9  Debug mode
50                10.2.10 Settle delay
51                10.2.11 Serial NVRAM
52                10.2.12 Exclude a host from being attached
53         10.3 Converting from old options
54         10.4 SCSI BUS checking boot option
55   11. SCSI problem troubleshooting
56         15.1 Problem tracking
57         15.2 Understanding hardware error reports
58   12. Serial NVRAM support (by Richard Waltham)
59         17.1 Features
60         17.2 Symbios NVRAM layout
61         17.3 Tekram  NVRAM layout
62
63
641. Introduction
65===============
66
67This driver supports the whole SYM53C8XX family of PCI-SCSI controllers.
68It also support the subset of LSI53C10XX PCI-SCSI controllers that are based
69on the SYM53C8XX SCRIPTS language.
70
71It replaces the sym53c8xx+ncr53c8xx driver bundle and shares its core code
72with the FreeBSD SYM-2 driver. The 'glue' that allows this driver to work
73under Linux is contained in 2 files named sym_glue.h and sym_glue.c.
74Other drivers files are intended not to depend on the Operating System
75on which the driver is used.
76
77The history of this driver can be summarized as follows:
78
791993: ncr driver written for 386bsd and FreeBSD by:
80
81          - Wolfgang Stanglmeier        <wolf@cologne.de>
82          - Stefan Esser                <se@mi.Uni-Koeln.de>
83
841996: port of the ncr driver to Linux-1.2.13 and rename it ncr53c8xx.
85
86          - Gerard Roudier
87
881998: new sym53c8xx driver for Linux based on LOAD/STORE instruction and that
89      adds full support for the 896 but drops support for early NCR devices.
90
91          - Gerard Roudier
92
931999: port of the sym53c8xx driver to FreeBSD and support for the LSI53C1010
94      33 MHz and 66MHz Ultra-3 controllers. The new driver is named 'sym'.
95
96          - Gerard Roudier
97
982000: Add support for early NCR devices to FreeBSD 'sym' driver.
99      Break the driver into several sources and separate the OS glue
100      code from the core code that can be shared among different O/Ses.
101      Write a glue code for Linux.
102
103          - Gerard Roudier
104
1052004: Remove FreeBSD compatibility code.  Remove support for versions of
106      Linux before 2.6.  Start using Linux facilities.
107
108This README file addresses the Linux version of the driver. Under FreeBSD,
109the driver documentation is the sym.8 man page.
110
111Information about new chips is available at LSILOGIC web server:
112
113          http://www.lsilogic.com/
114
115SCSI standard documentations are available at T10 site:
116
117          http://www.t10.org/
118
119Useful SCSI tools written by Eric Youngdale are part of most Linux
120distributions:
121
122   ============ ==========================
123   scsiinfo     command line tool
124   scsi-config  TCL/Tk tool using scsiinfo
125   ============ ==========================
126
1272. Supported chips and SCSI features
128====================================
129
130The following features are supported for all chips:
131
132	- Synchronous negotiation
133	- Disconnection
134	- Tagged command queuing
135	- SCSI parity checking
136	- PCI Master parity checking
137
138Other features depends on chip capabilities.
139
140The driver notably uses optimized SCRIPTS for devices that support
141LOAD/STORE and handles PHASE MISMATCH from SCRIPTS for devices that
142support the corresponding feature.
143
144The following table shows some characteristics of the chip family.
145
146+--------+-----------+-----+-----------+------------+------------+---------+
147|        |           |     |           |            |Load/store  |Hardware |
148|        |On board   |     |           |            |scripts     |phase    |
149|Chip    |SDMS BIOS  |Wide |SCSI std.  | Max. sync  |            |mismatch |
150+--------+-----------+-----+-----------+------------+------------+---------+
151|810     |     N     |  N  | FAST10    | 10 MB/s    |      N     |    N    |
152+--------+-----------+-----+-----------+------------+------------+---------+
153|810A    |     N     |  N  | FAST10    | 10 MB/s    |      Y     |    N    |
154+--------+-----------+-----+-----------+------------+------------+---------+
155|815     |     Y     |  N  | FAST10    | 10 MB/s    |      N     |    N    |
156+--------+-----------+-----+-----------+------------+------------+---------+
157|825     |     Y     |  Y  | FAST10    | 20 MB/s    |      N     |    N    |
158+--------+-----------+-----+-----------+------------+------------+---------+
159|825A    |     Y     |  Y  | FAST10    | 20 MB/s    |      Y     |    N    |
160+--------+-----------+-----+-----------+------------+------------+---------+
161|860     |     N     |  N  | FAST20    | 20 MB/s    |      Y     |    N    |
162+--------+-----------+-----+-----------+------------+------------+---------+
163|875     |     Y     |  Y  | FAST20    | 40 MB/s    |      Y     |    N    |
164+--------+-----------+-----+-----------+------------+------------+---------+
165|875A    |     Y     |  Y  | FAST20    | 40 MB/s    |      Y     |    Y    |
166+--------+-----------+-----+-----------+------------+------------+---------+
167|876     |     Y     |  Y  | FAST20    | 40 MB/s    |      Y     |    N    |
168+--------+-----------+-----+-----------+------------+------------+---------+
169|895     |     Y     |  Y  | FAST40    | 80 MB/s    |      Y     |    N    |
170+--------+-----------+-----+-----------+------------+------------+---------+
171|895A    |     Y     |  Y  | FAST40    | 80 MB/s    |      Y     |    Y    |
172+--------+-----------+-----+-----------+------------+------------+---------+
173|896     |     Y     |  Y  | FAST40    | 80 MB/s    |      Y     |    Y    |
174+--------+-----------+-----+-----------+------------+------------+---------+
175|897     |     Y     |  Y  | FAST40    | 80 MB/s    |      Y     |    Y    |
176+--------+-----------+-----+-----------+------------+------------+---------+
177|1510D   |     Y     |  Y  | FAST40    | 80 MB/s    |      Y     |    Y    |
178+--------+-----------+-----+-----------+------------+------------+---------+
179|1010    |     Y     |  Y  | FAST80    |160 MB/s    |      Y     |    Y    |
180+--------+-----------+-----+-----------+------------+------------+---------+
181|1010_66 |     Y     |  Y  | FAST80    |160 MB/s    |      Y     |    Y    |
182|[1]_    |           |     |           |            |            |         |
183+--------+-----------+-----+-----------+------------+------------+---------+
184
185.. [1] Chip supports 33MHz and 66MHz PCI bus clock.
186
187
188Summary of other supported features:
189
190:Module:                allow to load the driver
191:Memory mapped I/O:     increases performance
192:Control commands:      write operations to the proc SCSI file system
193:Debugging information: written to syslog (expert only)
194:Serial NVRAM:          Symbios and Tekram formats
195
196- Scatter / gather
197- Shared interrupt
198- Boot setup commands
199
200
2013. Advantages of this driver for newer chips.
202=============================================
203
2043.1 Optimized SCSI SCRIPTS
205--------------------------
206
207All chips except the 810, 815 and 825, support new SCSI SCRIPTS instructions
208named LOAD and STORE that allow to move up to 1 DWORD from/to an IO register
209to/from memory much faster that the MOVE MEMORY instruction that is supported
210by the 53c7xx and 53c8xx family.
211
212The LOAD/STORE instructions support absolute and DSA relative addressing
213modes. The SCSI SCRIPTS had been entirely rewritten using LOAD/STORE instead
214of MOVE MEMORY instructions.
215
216Due to the lack of LOAD/STORE SCRIPTS instructions by earlier chips, this
217driver also incorporates a different SCRIPTS set based on MEMORY MOVE, in
218order to provide support for the entire SYM53C8XX chips family.
219
2203.2 New features appeared with the SYM53C896
221--------------------------------------------
222
223Newer chips (see above) allows handling of the phase mismatch context from
224SCRIPTS (avoids the phase mismatch interrupt that stops the SCSI processor
225until the C code has saved the context of the transfer).
226
227The 896 and 1010 chips support 64 bit PCI transactions and addressing,
228while the 895A supports 32 bit PCI transactions and 64 bit addressing.
229The SCRIPTS processor of these chips is not true 64 bit, but uses segment
230registers for bit 32-63. Another interesting feature is that LOAD/STORE
231instructions that address the on-chip RAM (8k) remain internal to the chip.
232
2334. Memory mapped I/O versus normal I/O
234======================================
235
236Memory mapped I/O has less latency than normal I/O and is the recommended
237way for doing IO with PCI devices. Memory mapped I/O seems to work fine on
238most hardware configurations, but some poorly designed chipsets may break
239this feature. A configuration option is provided for normal I/O to be
240used but the driver defaults to MMIO.
241
2425. Tagged command queueing
243==========================
244
245Queuing more than 1 command at a time to a device allows it to perform
246optimizations based on actual head positions and its mechanical
247characteristics. This feature may also reduce average command latency.
248In order to really gain advantage of this feature, devices must have
249a reasonable cache size (No miracle is to be expected for a low-end
250hard disk with 128 KB or less).
251
252Some known old SCSI devices do not properly support tagged command queuing.
253Generally, firmware revisions that fix this kind of problems are available
254at respective vendor web/ftp sites.
255
256All I can say is that I never have had problem with tagged queuing using
257this driver and its predecessors. Hard disks that behaved correctly for
258me using tagged commands are the following:
259
260- IBM S12 0662
261- Conner 1080S
262- Quantum Atlas I
263- Quantum Atlas II
264- Seagate Cheetah I
265- Quantum Viking II
266- IBM DRVS
267- Quantum Atlas IV
268- Seagate Cheetah II
269
270If your controller has NVRAM, you can configure this feature per target
271from the user setup tool. The Tekram Setup program allows to tune the
272maximum number of queued commands up to 32. The Symbios Setup only allows
273to enable or disable this feature.
274
275The maximum number of simultaneous tagged commands queued to a device
276is currently set to 16 by default.  This value is suitable for most SCSI
277disks.  With large SCSI disks (>= 2GB, cache >= 512KB, average seek time
278<= 10 ms), using a larger value may give better performances.
279
280This driver supports up to 255 commands per device, and but using more than
28164 is generally not worth-while, unless you are using a very large disk or
282disk arrays. It is noticeable that most of recent hard disks seem not to
283accept more than 64 simultaneous commands. So, using more than 64 queued
284commands is probably just resource wasting.
285
286If your controller does not have NVRAM or if it is managed by the SDMS
287BIOS/SETUP, you can configure tagged queueing feature and device queue
288depths from the boot command-line. For example::
289
290  sym53c8xx=tags:4/t2t3q15-t4q7/t1u0q32
291
292will set tagged commands queue depths as follow:
293
294- target 2  all luns  on controller 0 --> 15
295- target 3  all luns  on controller 0 --> 15
296- target 4  all luns  on controller 0 -->  7
297- target 1  lun 0     on controller 1 --> 32
298- all other target/lun                -->  4
299
300In some special conditions, some SCSI disk firmwares may return a
301QUEUE FULL status for a SCSI command. This behaviour is managed by the
302driver using the following heuristic:
303
304- Each time a QUEUE FULL status is returned, tagged queue depth is reduced
305  to the actual number of disconnected commands.
306
307- Every 200 successfully completed SCSI commands, if allowed by the
308  current limit, the maximum number of queueable commands is incremented.
309
310Since QUEUE FULL status reception and handling is resource wasting, the
311driver notifies by default this problem to user by indicating the actual
312number of commands used and their status, as well as its decision on the
313device queue depth change.
314The heuristic used by the driver in handling QUEUE FULL ensures that the
315impact on performances is not too bad. You can get rid of the messages by
316setting verbose level to zero, as follow:
317
3181st method:
319	    boot your system using 'sym53c8xx=verb:0' option.
3202nd method:
321	    apply "setverbose 0" control command to the proc fs entry
322            corresponding to your controller after boot-up.
323
3246. Parity checking
325==================
326
327The driver supports SCSI parity checking and PCI bus master parity
328checking.  These features must be enabled in order to ensure safe
329data transfers.  Some flawed devices or mother boards may have problems
330with parity.  The options to defeat parity checking have been removed
331from the driver.
332
3337. Profiling information
334========================
335
336This driver does not provide profiling information as did its predecessors.
337This feature was not this useful and added complexity to the code.
338As the driver code got more complex, I have decided to remove everything
339that didn't seem actually useful.
340
3418. Control commands
342===================
343
344Control commands can be sent to the driver with write operations to
345the proc SCSI file system. The generic command syntax is the
346following::
347
348      echo "<verb> <parameters>" >/proc/scsi/sym53c8xx/0
349      (assumes controller number is 0)
350
351Using "all" for "<target>" parameter with the commands below will
352apply to all targets of the SCSI chain (except the controller).
353
354Available commands:
355
3568.1 Set minimum synchronous period factor
357-----------------------------------------
358
359    setsync <target> <period factor>
360
361    :target:   target number
362    :period:   minimum synchronous period.
363               Maximum speed = 1000/(4*period factor) except for special
364               cases below.
365
366    Specify a period of 0, to force asynchronous transfer mode.
367
368     -  9 means 12.5 nano-seconds synchronous period
369     - 10 means 25 nano-seconds synchronous period
370     - 11 means 30 nano-seconds synchronous period
371     - 12 means 50 nano-seconds synchronous period
372
3738.2 Set wide size
374-----------------
375
376    setwide <target> <size>
377
378    :target:   target number
379    :size:     0=8 bits, 1=16bits
380
3818.3 Set maximum number of concurrent tagged commands
382----------------------------------------------------
383
384    settags <target> <tags>
385
386    :target:   target number
387    :tags:     number of concurrent tagged commands
388               must not be greater than configured (default: 16)
389
3908.4 Set debug mode
391------------------
392
393    setdebug <list of debug flags>
394
395    Available debug flags:
396
397	======== ========================================================
398        alloc    print info about memory allocations (ccb, lcb)
399        queue    print info about insertions into the command start queue
400        result   print sense data on CHECK CONDITION status
401        scatter  print info about the scatter process
402        scripts  print info about the script binding process
403	tiny     print minimal debugging information
404	timing   print timing information of the NCR chip
405	nego     print information about SCSI negotiations
406	phase    print information on script interruptions
407	======== ========================================================
408
409    Use "setdebug" with no argument to reset debug flags.
410
411
4128.5 Set flag (no_disc)
413----------------------
414
415    setflag <target> <flag>
416
417    :target:    target number
418
419    For the moment, only one flag is available:
420
421        no_disc:   not allow target to disconnect.
422
423    Do not specify any flag in order to reset the flag. For example:
424
425    setflag 4
426      will reset no_disc flag for target 4, so will allow it disconnections.
427    setflag all
428      will allow disconnection for all devices on the SCSI bus.
429
430
4318.6 Set verbose level
432---------------------
433
434    setverbose #level
435
436    The driver default verbose level is 1. This command allows to change
437    th driver verbose level after boot-up.
438
4398.7 Reset all logical units of a target
440---------------------------------------
441
442    resetdev <target>
443
444    :target:    target number
445
446    The driver will try to send a BUS DEVICE RESET message to the target.
447
4488.8 Abort all tasks of all logical units of a target
449----------------------------------------------------
450
451    cleardev <target>
452
453    :target:    target number
454
455    The driver will try to send a ABORT message to all the logical units
456    of the target.
457
458
4599. Configuration parameters
460===========================
461
462Under kernel configuration tools (make menuconfig, for example), it is
463possible to change some default driver configuration parameters.
464If the firmware of all your devices is perfect enough, all the
465features supported by the driver can be enabled at start-up. However,
466if only one has a flaw for some SCSI feature, you can disable the
467support by the driver of this feature at linux start-up and enable
468this feature after boot-up only for devices that support it safely.
469
470Configuration parameters:
471
472Use normal IO                         (default answer: n)
473    Answer "y" if you suspect your mother board to not allow memory mapped I/O.
474    May slow down performance a little.
475
476Default tagged command queue depth    (default answer: 16)
477    Entering 0 defaults to tagged commands not being used.
478    This parameter can be specified from the boot command line.
479
480Maximum number of queued commands     (default answer: 32)
481    This option allows you to specify the maximum number of tagged commands
482    that can be queued to a device. The maximum supported value is 255.
483
484Synchronous transfers frequency       (default answer: 80)
485    This option allows you to specify the frequency in MHz the driver
486    will use at boot time for synchronous data transfer negotiations.
487    0 means "asynchronous data transfers".
488
48910. Boot setup commands
490=======================
491
49210.1 Syntax
493-----------
494
495Setup commands can be passed to the driver either at boot time or as
496parameters to modprobe, as described in Documentation/admin-guide/kernel-parameters.rst
497
498Example of boot setup command under lilo prompt::
499
500    lilo: linux root=/dev/sda2 sym53c8xx.cmd_per_lun=4 sym53c8xx.sync=10 sym53c8xx.debug=0x200
501
502- enable tagged commands, up to 4 tagged commands queued.
503- set synchronous negotiation speed to 10 Mega-transfers / second.
504- set DEBUG_NEGO flag.
505
506The following command will install the driver module with the same
507options as above::
508
509    modprobe sym53c8xx cmd_per_lun=4 sync=10 debug=0x200
510
51110.2 Available arguments
512------------------------
513
51410.2.1  Default number of tagged commands
515^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
516        - cmd_per_lun=0 (or cmd_per_lun=1) tagged command queuing disabled
517        - cmd_per_lun=#tags (#tags > 1) tagged command queuing enabled
518
519  #tags will be truncated to the max queued commands configuration parameter.
520
52110.2.2 Burst max
522^^^^^^^^^^^^^^^^
523
524	========== ======================================================
525        burst=0    burst disabled
526        burst=255  get burst length from initial IO register settings.
527        burst=#x   burst enabled (1<<#x burst transfers max)
528
529		   #x is an integer value which is log base 2 of the burst
530		   transfers max.
531	========== ======================================================
532
533  By default the driver uses the maximum value supported by the chip.
534
53510.2.3 LED support
536^^^^^^^^^^^^^^^^^^
537
538	=====      ===================
539        led=1      enable  LED support
540        led=0      disable LED support
541	=====      ===================
542
543  Do not enable LED support if your scsi board does not use SDMS BIOS.
544  (See 'Configuration parameters')
545
54610.2.4 Differential mode
547^^^^^^^^^^^^^^^^^^^^^^^^
548
549	======	=================================
550	diff=0	never set up diff mode
551        diff=1	set up diff mode if BIOS set it
552        diff=2	always set up diff mode
553        diff=3	set diff mode if GPIO3 is not set
554	======	=================================
555
55610.2.5 IRQ mode
557^^^^^^^^^^^^^^^
558
559	======     ================================================
560        irqm=0     always open drain
561        irqm=1     same as initial settings (assumed BIOS settings)
562        irqm=2     always totem pole
563	======     ================================================
564
56510.2.6 Check SCSI BUS
566^^^^^^^^^^^^^^^^^^^^^
567
568        buschk=<option bits>
569
570    Available option bits:
571
572	===    ================================================
573        0x0    No check.
574        0x1    Check and do not attach the controller on error.
575        0x2    Check and just warn on error.
576	===    ================================================
577
57810.2.7 Suggest a default SCSI id for hosts
579^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
580
581	==========	==========================================
582        hostid=255	no id suggested.
583        hostid=#x	(0 < x < 7) x suggested for hosts SCSI id.
584	==========	==========================================
585
586    If a host SCSI id is available from the NVRAM, the driver will ignore
587    any value suggested as boot option. Otherwise, if a suggested value
588    different from 255 has been supplied, it will use it. Otherwise, it will
589    try to deduce the value previously set in the hardware and use value
590    7 if the hardware value is zero.
591
59210.2.8  Verbosity level
593^^^^^^^^^^^^^^^^^^^^^^^
594
595	======     ========
596        verb=0     minimal
597        verb=1     normal
598        verb=2     too much
599	======     ========
600
60110.2.9 Debug mode
602^^^^^^^^^^^^^^^^^
603
604	=========   ====================================
605        debug=0	    clear debug flags
606        debug=#x    set debug flags
607
608		    #x is an integer value combining the
609		    following power-of-2 values:
610
611		    =============  ======
612		    DEBUG_ALLOC       0x1
613		    DEBUG_PHASE       0x2
614		    DEBUG_POLL        0x4
615		    DEBUG_QUEUE       0x8
616		    DEBUG_RESULT     0x10
617		    DEBUG_SCATTER    0x20
618		    DEBUG_SCRIPT     0x40
619		    DEBUG_TINY       0x80
620		    DEBUG_TIMING    0x100
621		    DEBUG_NEGO      0x200
622		    DEBUG_TAGS      0x400
623		    DEBUG_FREEZE    0x800
624		    DEBUG_RESTART  0x1000
625		    =============  ======
626	=========   ====================================
627
628  You can play safely with DEBUG_NEGO. However, some of these flags may
629  generate bunches of syslog messages.
630
63110.2.10 Settle delay
632^^^^^^^^^^^^^^^^^^^^
633
634	========	===================
635        settle=n	delay for n seconds
636	========	===================
637
638  After a bus reset, the driver will delay for n seconds before talking
639  to any device on the bus.  The default is 3 seconds and safe mode will
640  default it to 10.
641
64210.2.11 Serial NVRAM
643^^^^^^^^^^^^^^^^^^^^
644
645	.. Note:: option not currently implemented.
646
647	=======     =========================================
648        nvram=n     do not look for serial NVRAM
649        nvram=y     test controllers for onboard serial NVRAM
650	=======     =========================================
651
652        (alternate binary form)
653
654        nvram=<bits options>
655
656        ====   =================================================================
657        0x01   look for NVRAM  (equivalent to nvram=y)
658        0x02   ignore NVRAM "Synchronous negotiation" parameters for all devices
659        0x04   ignore NVRAM "Wide negotiation"  parameter for all devices
660        0x08   ignore NVRAM "Scan at boot time" parameter for all devices
661        0x80   also attach controllers set to OFF in the NVRAM (sym53c8xx only)
662        ====   =================================================================
663
66410.2.12 Exclude a host from being attached
665^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
666
667        excl=<io_address>,...
668
669    Prevent host at a given io address from being attached.
670    For example 'excl=0xb400,0xc000' indicate to the
671    driver not to attach hosts at address 0xb400 and 0xc000.
672
67310.3 Converting from old style options
674--------------------------------------
675
676Previously, the sym2 driver accepted arguments of the form::
677
678	sym53c8xx=tags:4,sync:10,debug:0x200
679
680As a result of the new module parameters, this is no longer available.
681Most of the options have remained the same, but tags has become
682cmd_per_lun to reflect its different purposes.  The sample above would
683be specified as::
684
685	modprobe sym53c8xx cmd_per_lun=4 sync=10 debug=0x200
686
687or on the kernel boot line as::
688
689	sym53c8xx.cmd_per_lun=4 sym53c8xx.sync=10 sym53c8xx.debug=0x200
690
69110.4 SCSI BUS checking boot option
692----------------------------------
693
694When this option is set to a non-zero value, the driver checks SCSI lines
695logic state, 100 micro-seconds after having asserted the SCSI RESET line.
696The driver just reads SCSI lines and checks all lines read FALSE except RESET.
697Since SCSI devices shall release the BUS at most 800 nano-seconds after SCSI
698RESET has been asserted, any signal to TRUE may indicate a SCSI BUS problem.
699Unfortunately, the following common SCSI BUS problems are not detected:
700
701- Only 1 terminator installed.
702- Misplaced terminators.
703- Bad quality terminators.
704
705On the other hand, either bad cabling, broken devices, not conformant
706devices, ... may cause a SCSI signal to be wrong when the driver reads it.
707
70815. SCSI problem troubleshooting
709================================
710
71115.1 Problem tracking
712---------------------
713
714Most SCSI problems are due to a non conformant SCSI bus or too buggy
715devices.  If unfortunately you have SCSI problems, you can check the
716following things:
717
718- SCSI bus cables
719- terminations at both end of the SCSI chain
720- linux syslog messages (some of them may help you)
721
722If you do not find the source of problems, you can configure the
723driver or devices in the NVRAM with minimal features.
724
725- only asynchronous data transfers
726- tagged commands disabled
727- disconnections not allowed
728
729Now, if your SCSI bus is ok, your system has every chance to work
730with this safe configuration but performances will not be optimal.
731
732If it still fails, then you can send your problem description to
733appropriate mailing lists or news-groups.  Send me a copy in order to
734be sure I will receive it.  Obviously, a bug in the driver code is
735possible.
736
737  My current email address: Gerard Roudier <groudier@free.fr>
738
739Allowing disconnections is important if you use several devices on
740your SCSI bus but often causes problems with buggy devices.
741Synchronous data transfers increases throughput of fast devices like
742hard disks.  Good SCSI hard disks with a large cache gain advantage of
743tagged commands queuing.
744
74515.2 Understanding hardware error reports
746-----------------------------------------
747
748When the driver detects an unexpected error condition, it may display a
749message of the following pattern::
750
751    sym0:1: ERROR (0:48) (1-21-65) (f/95/0) @ (script 7c0:19000000).
752    sym0: script cmd = 19000000
753    sym0: regdump: da 10 80 95 47 0f 01 07 75 01 81 21 80 01 09 00.
754
755Some fields in such a message may help you understand the cause of the
756problem, as follows::
757
758    sym0:1: ERROR (0:48) (1-21-65) (f/95/0) @ (script 7c0:19000000).
759    .....A.........B.C....D.E..F....G.H..I.......J.....K...L.......
760
761Field A : target number.
762  SCSI ID of the device the controller was talking with at the moment the
763  error occurs.
764
765Field B : DSTAT io register (DMA STATUS)
766  ========   =============================================================
767  Bit 0x40   MDPE Master Data Parity Error
768             Data parity error detected on the PCI BUS.
769  Bit 0x20   BF   Bus Fault
770             PCI bus fault condition detected
771  Bit 0x01   IID  Illegal Instruction Detected
772             Set by the chip when it detects an Illegal Instruction format
773             on some condition that makes an instruction illegal.
774  Bit 0x80   DFE Dma Fifo Empty
775             Pure status bit that does not indicate an error.
776  ========   =============================================================
777
778  If the reported DSTAT value contains a combination of MDPE (0x40),
779  BF (0x20), then the cause may be likely due to a PCI BUS problem.
780
781Field C : SIST io register (SCSI Interrupt Status)
782  ========   ==================================================================
783  Bit 0x08   SGE  SCSI GROSS ERROR
784             Indicates that the chip detected a severe error condition
785             on the SCSI BUS that prevents the SCSI protocol from functioning
786             properly.
787  Bit 0x04   UDC  Unexpected Disconnection
788             Indicates that the device released the SCSI BUS when the chip
789             was not expecting this to happen. A device may behave so to
790             indicate the SCSI initiator that an error condition not reportable              using the SCSI protocol has occurred.
791  Bit 0x02   RST  SCSI BUS Reset
792             Generally SCSI targets do not reset the SCSI BUS, although any
793             device on the BUS can reset it at any time.
794  Bit 0x01   PAR  Parity
795             SCSI parity error detected.
796  ========   ==================================================================
797
798  On a faulty SCSI BUS, any error condition among SGE (0x08), UDC (0x04) and
799  PAR (0x01) may be detected by the chip. If your SCSI system sometimes
800  encounters such error conditions, especially SCSI GROSS ERROR, then a SCSI
801  BUS problem is likely the cause of these errors.
802
803For fields D,E,F,G and H, you may look into the sym53c8xx_defs.h file
804that contains some minimal comments on IO register bits.
805
806Field D : SOCL  Scsi Output Control Latch
807          This register reflects the state of the SCSI control lines the
808          chip want to drive or compare against.
809Field E : SBCL  Scsi Bus Control Lines
810          Actual value of control lines on the SCSI BUS.
811Field F : SBDL  Scsi Bus Data Lines
812          Actual value of data lines on the SCSI BUS.
813Field G : SXFER  SCSI Transfer
814          Contains the setting of the Synchronous Period for output and
815          the current Synchronous offset (offset 0 means asynchronous).
816Field H : SCNTL3 Scsi Control Register 3
817          Contains the setting of timing values for both asynchronous and
818          synchronous data transfers.
819Field I : SCNTL4 Scsi Control Register 4
820          Only meaningful for 53C1010 Ultra3 controllers.
821
822Understanding Fields J, K, L and dumps requires to have good knowledge of
823SCSI standards, chip cores functionnals and internal driver data structures.
824You are not required to decode and understand them, unless you want to help
825maintain the driver code.
826
82717. Serial NVRAM (added by Richard Waltham: dormouse@farsrobt.demon.co.uk)
828==========================================================================
829
83017.1 Features
831-------------
832
833Enabling serial NVRAM support enables detection of the serial NVRAM included
834on Symbios and some Symbios compatible host adaptors, and Tekram boards. The
835serial NVRAM is used by Symbios and Tekram to hold set up parameters for the
836host adaptor and its attached drives.
837
838The Symbios NVRAM also holds data on the boot order of host adaptors in a
839system with more than one host adaptor.  This information is no longer used
840as it's fundamentally incompatible with the hotplug PCI model.
841
842Tekram boards using Symbios chips, DC390W/F/U, which have NVRAM are detected
843and this is used to distinguish between Symbios compatible and Tekram host
844adaptors. This is used to disable the Symbios compatible "diff" setting
845incorrectly set on Tekram boards if the CONFIG_SCSI_53C8XX_SYMBIOS_COMPAT
846configuration parameter is set enabling both Symbios and Tekram boards to be
847used together with the Symbios cards using all their features, including
848"diff" support. ("led pin" support for Symbios compatible cards can remain
849enabled when using Tekram cards. It does nothing useful for Tekram host
850adaptors but does not cause problems either.)
851
852The parameters the driver is able to get from the NVRAM depend on the
853data format used, as follow:
854
855+-------------------------------+------------------+--------------+
856|                               |Tekram format     |Symbios format|
857+-------------------------------+------------------+--------------+
858|General and host parameters    |                  |              |
859+-------------------------------+------------------+--------------+
860|  * Boot order                 |        N         |       Y      |
861+-------------------------------+------------------+--------------+
862|  * Host SCSI ID               |        Y         |       Y      |
863+-------------------------------+------------------+--------------+
864|  * SCSI parity checking       |        Y         |       Y      |
865+-------------------------------+------------------+--------------+
866|  * Verbose boot messages      |        N         |       Y      |
867+-------------------------------+------------------+--------------+
868|SCSI devices parameters                                          |
869+-------------------------------+------------------+--------------+
870|  * Synchronous transfer speed |        Y         |       Y      |
871+-------------------------------+------------------+--------------+
872|  * Wide 16 / Narrow           |        Y         |       Y      |
873+-------------------------------+------------------+--------------+
874|  * Tagged Command Queuing     |        Y         |       Y      |
875|    enabled                    |                  |              |
876+-------------------------------+------------------+--------------+
877|  * Disconnections enabled     |        Y         |       Y      |
878+-------------------------------+------------------+--------------+
879|  * Scan at boot time          |        N         |       Y      |
880+-------------------------------+------------------+--------------+
881
882
883In order to speed up the system boot, for each device configured without
884the "scan at boot time" option, the driver forces an error on the
885first TEST UNIT READY command received for this device.
886
887
88817.2 Symbios NVRAM layout
889-------------------------
890
891typical data at NVRAM address 0x100 (53c810a NVRAM)::
892
893    00 00
894    64 01
895    8e 0b
896
897    00 30 00 00 00 00 07 00 00 00 00 00 00 00 07 04 10 04 00 00
898
899    04 00 0f 00 00 10 00 50 00 00 01 00 00 62
900    04 00 03 00 00 10 00 58 00 00 01 00 00 63
901    04 00 01 00 00 10 00 48 00 00 01 00 00 61
902    00 00 00 00 00 00 00 00 00 00 00 00 00 00
903
904    0f 00 08 08 64 00 0a 00
905    0f 00 08 08 64 00 0a 00
906    0f 00 08 08 64 00 0a 00
907    0f 00 08 08 64 00 0a 00
908    0f 00 08 08 64 00 0a 00
909    0f 00 08 08 64 00 0a 00
910    0f 00 08 08 64 00 0a 00
911    0f 00 08 08 64 00 0a 00
912
913    0f 00 08 08 64 00 0a 00
914    0f 00 08 08 64 00 0a 00
915    0f 00 08 08 64 00 0a 00
916    0f 00 08 08 64 00 0a 00
917    0f 00 08 08 64 00 0a 00
918    0f 00 08 08 64 00 0a 00
919    0f 00 08 08 64 00 0a 00
920    0f 00 08 08 64 00 0a 00
921
922    00 00 00 00 00 00 00 00
923    00 00 00 00 00 00 00 00
924    00 00 00 00 00 00 00 00
925    00 00 00 00 00 00 00 00
926    00 00 00 00 00 00 00 00
927    00 00 00 00 00 00 00 00
928    00 00 00 00 00 00 00 00
929    00 00 00 00 00 00 00 00
930
931    00 00 00 00 00 00 00 00
932    00 00 00 00 00 00 00 00
933    00 00 00 00 00 00 00 00
934    00 00 00 00 00 00 00 00
935    00 00 00 00 00 00 00 00
936    00 00 00 00 00 00 00 00
937    00 00 00 00 00 00 00 00
938    00 00 00 00 00 00 00 00
939
940    00 00 00 00 00 00 00 00
941    00 00 00 00 00 00 00 00
942    00 00 00 00 00 00 00 00
943
944    fe fe
945    00 00
946    00 00
947
948NVRAM layout details
949
950============= =================
951NVRAM Address
952============= =================
9530x000-0x0ff   not used
9540x100-0x26f   initialised data
9550x270-0x7ff   not used
956============= =================
957
958general layout::
959
960        header  -   6 bytes,
961        data    - 356 bytes (checksum is byte sum of this data)
962        trailer -   6 bytes
963                  ---
964        total     368 bytes
965
966data area layout::
967
968        controller set up  -  20 bytes
969        boot configuration -  56 bytes (4x14 bytes)
970        device set up      - 128 bytes (16x8 bytes)
971        unused (spare?)    - 152 bytes (19x8 bytes)
972                             ---
973        total                356 bytes
974
975header::
976
977    00 00   - ?? start marker
978    64 01   - byte count (lsb/msb excludes header/trailer)
979    8e 0b   - checksum (lsb/msb excludes header/trailer)
980
981controller set up::
982
983    00 30 00 00 00 00 07 00 00 00 00 00 00 00 07 04 10 04 00 00
984		    |     |           |     |
985		    |     |           |      -- host ID
986		    |     |           |
987		    |     |            --Removable Media Support
988		    |     |               0x00 = none
989		    |     |               0x01 = Bootable Device
990		    |     |               0x02 = All with Media
991		    |     |
992		    |      --flag bits 2
993		    |        0x00000001= scan order hi->low
994		    |            (default 0x00 - scan low->hi)
995			--flag bits 1
996			0x00000001 scam enable
997			0x00000010 parity enable
998			0x00000100 verbose boot msgs
999
1000remaining bytes unknown - they do not appear to change in my
1001current set up for any of the controllers.
1002
1003default set up is identical for 53c810a and 53c875 NVRAM
1004(Removable Media added Symbios BIOS version 4.09)
1005
1006boot configuration
1007
1008boot order set by order of the devices in this table::
1009
1010    04 00 0f 00 00 10 00 50 00 00 01 00 00 62 -- 1st controller
1011    04 00 03 00 00 10 00 58 00 00 01 00 00 63    2nd controller
1012    04 00 01 00 00 10 00 48 00 00 01 00 00 61    3rd controller
1013    00 00 00 00 00 00 00 00 00 00 00 00 00 00    4th controller
1014	|  |  |  |     |        |     |  |
1015	|  |  |  |     |        |      ---- PCI io port adr
1016	|  |  |  |     |         --0x01 init/scan at boot time
1017	|  |  |  |      --PCI device/function number (0xdddddfff)
1018	|  |   ----- ?? PCI vendor ID (lsb/msb)
1019	    ----PCI device ID (lsb/msb)
1020
1021?? use of this data is a guess but seems reasonable
1022
1023remaining bytes unknown - they do not appear to change in my
1024current set up
1025
1026default set up is identical for 53c810a and 53c875 NVRAM
1027
1028device set up (up to 16 devices - includes controller)::
1029
1030    0f 00 08 08 64 00 0a 00 - id 0
1031    0f 00 08 08 64 00 0a 00
1032    0f 00 08 08 64 00 0a 00
1033    0f 00 08 08 64 00 0a 00
1034    0f 00 08 08 64 00 0a 00
1035    0f 00 08 08 64 00 0a 00
1036    0f 00 08 08 64 00 0a 00
1037    0f 00 08 08 64 00 0a 00
1038
1039    0f 00 08 08 64 00 0a 00
1040    0f 00 08 08 64 00 0a 00
1041    0f 00 08 08 64 00 0a 00
1042    0f 00 08 08 64 00 0a 00
1043    0f 00 08 08 64 00 0a 00
1044    0f 00 08 08 64 00 0a 00
1045    0f 00 08 08 64 00 0a 00
1046    0f 00 08 08 64 00 0a 00 - id 15
1047    |     |  |  |     |  |
1048    |     |  |  |      ----timeout (lsb/msb)
1049    |     |  |   --synch period (0x?? 40 Mtrans/sec- fast 40) (probably 0x28)
1050    |     |  |                  (0x30 20 Mtrans/sec- fast 20)
1051    |     |  |                  (0x64 10 Mtrans/sec- fast )
1052    |     |  |                  (0xc8  5 Mtrans/sec)
1053    |     |  |                  (0x00  asynchronous)
1054    |     |   -- ?? max sync offset (0x08 in NVRAM on 53c810a)
1055    |     |                         (0x10 in NVRAM on 53c875)
1056    |      --device bus width (0x08 narrow)
1057    |                         (0x10 16 bit wide)
1058    --flag bits
1059	0x00000001 - disconnect enabled
1060	0x00000010 - scan at boot time
1061	0x00000100 - scan luns
1062	0x00001000 - queue tags enabled
1063
1064remaining bytes unknown - they do not appear to change in my
1065current set up
1066
1067?? use of this data is a guess but seems reasonable
1068(but it could be max bus width)
1069
1070default set up for 53c810a NVRAM
1071default set up for 53c875 NVRAM
1072
1073				- bus width     - 0x10
1074                                - sync offset ? - 0x10
1075                                - sync period   - 0x30
1076
1077?? spare device space (32 bit bus ??)::
1078
1079    00 00 00 00 00 00 00 00  (19x8bytes)
1080    .
1081    .
1082    00 00 00 00 00 00 00 00
1083
1084default set up is identical for 53c810a and 53c875 NVRAM
1085
1086trailer::
1087
1088    fe fe   - ? end marker ?
1089    00 00
1090    00 00
1091
1092default set up is identical for 53c810a and 53c875 NVRAM
1093
109417.3 Tekram NVRAM layout
1095------------------------
1096
1097nvram 64x16 (1024 bit)
1098
1099Drive settings::
1100
1101    Drive ID 0-15 (addr 0x0yyyy0 = device setup, yyyy = ID)
1102		(addr 0x0yyyy1 = 0x0000)
1103
1104	x x x x  x x x x  x x x x  x x x x
1105		| | |      | |  | | | |
1106		| | |      | |  | | |  ----- parity check   0 - off
1107		| | |      | |  | | |                       1 - on
1108		| | |      | |  | | |
1109		| | |      | |  | |  ------- sync neg       0 - off
1110		| | |      | |  | |                         1 - on
1111		| | |      | |  | |
1112		| | |      | |  |  --------- disconnect     0 - off
1113		| | |      | |  |                           1 - on
1114		| | |      | |  |
1115		| | |      | |   ----------- start cmd      0 - off
1116		| | |      | |                              1 - on
1117		| | |      | |
1118		| | |      |  -------------- tagged cmds    0 - off
1119		| | |      |                                1 - on
1120		| | |      |
1121		| | |       ---------------- wide neg       0 - off
1122		| | |                                       1 - on
1123		| | |
1124		    --------------------------- sync rate      0 - 10.0 Mtrans/sec
1125							    1 -  8.0
1126							    2 -  6.6
1127							    3 -  5.7
1128							    4 -  5.0
1129							    5 -  4.0
1130							    6 -  3.0
1131							    7 -  2.0
1132							    7 -  2.0
1133							    8 - 20.0
1134							    9 - 16.7
1135							    a - 13.9
1136							    b - 11.9
1137
1138Global settings
1139
1140Host flags 0 (addr 0x100000, 32)::
1141
1142    x x x x  x x x x  x x x x  x x x x
1143    | | | |  | | | |           | | | |
1144    | | | |  | | | |            ----------- host ID    0x00 - 0x0f
1145    | | | |  | | | |
1146    | | | |  | | |  ----------------------- support for    0 - off
1147    | | | |  | | |                          > 2 drives     1 - on
1148    | | | |  | | |
1149    | | | |  | |  ------------------------- support drives 0 - off
1150    | | | |  | |                            > 1Gbytes      1 - on
1151    | | | |  | |
1152    | | | |  |  --------------------------- bus reset on   0 - off
1153    | | | |  |                                power on     1 - on
1154    | | | |  |
1155    | | | |   ----------------------------- active neg     0 - off
1156    | | | |                                                1 - on
1157    | | | |
1158    | | |  -------------------------------- imm seek       0 - off
1159    | | |                                                  1 - on
1160    | | |
1161    | |  ---------------------------------- scan luns      0 - off
1162    | |                                                    1 - on
1163    | |
1164     -------------------------------------- removable      0 - disable
1165                                            as BIOS dev    1 - boot device
1166                                                           2 - all
1167
1168Host flags 1 (addr 0x100001, 33)::
1169
1170    x x x x  x x x x  x x x x  x x x x
1171               | | |             | | |
1172               | | |              --------- boot delay     0 -   3 sec
1173               | | |                                       1 -   5
1174               | | |                                       2 -  10
1175               | | |                                       3 -  20
1176               | | |                                       4 -  30
1177               | | |                                       5 -  60
1178               | | |                                       6 - 120
1179               | | |
1180                --------------------------- max tag cmds   0 -  2
1181                                                           1 -  4
1182                                                           2 -  8
1183                                                           3 - 16
1184                                                           4 - 32
1185
1186Host flags 2 (addr 0x100010, 34)::
1187
1188    x x x x  x x x x  x x x x  x x x x
1189                                     |
1190                                      ----- F2/F6 enable   0 - off ???
1191                                                           1 - on  ???
1192
1193checksum (addr 0x111111)
1194
1195checksum = 0x1234 - (sum addr 0-63)
1196
1197----------------------------------------------------------------------------
1198
1199default nvram data::
1200
1201    0x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
1202    0x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
1203    0x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
1204    0x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
1205
1206    0x0f07 0x0400 0x0001 0x0000 0x0000 0x0000 0x0000 0x0000
1207    0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000
1208    0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000
1209    0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0xfbbc
1210