Root/Documentation/scsi/ncr53c8xx.txt

1The Linux NCR53C8XX/SYM53C8XX drivers README file
2
3Written by Gerard Roudier <groudier@free.fr>
421 Rue Carnot
595170 DEUIL LA BARRE - FRANCE
6
729 May 1999
8===============================================================================
9
101. Introduction
112. Supported chips and SCSI features
123. Advantages of the enhanced 896 driver
13      3.1 Optimized SCSI SCRIPTS
14      3.2 New features of the SYM53C896 (64 bit PCI dual LVD SCSI controller)
154. Memory mapped I/O versus normal I/O
165. Tagged command queueing
176. Parity checking
187. Profiling information
198. Control commands
20      8.1 Set minimum synchronous period
21      8.2 Set wide size
22      8.3 Set maximum number of concurrent tagged commands
23      8.4 Set order type for tagged command
24      8.5 Set debug mode
25      8.6 Clear profile counters
26      8.7 Set flag (no_disc)
27      8.8 Set verbose level
28      8.9 Reset all logical units of a target
29      8.10 Abort all tasks of all logical units of a target
309. Configuration parameters
3110. Boot setup commands
32      10.1 Syntax
33      10.2 Available arguments
34             10.2.1 Master parity checking
35             10.2.2 Scsi parity checking
36             10.2.3 Scsi disconnections
37             10.2.4 Special features
38             10.2.5 Ultra SCSI support
39             10.2.6 Default number of tagged commands
40             10.2.7 Default synchronous period factor
41             10.2.8 Negotiate synchronous with all devices
42             10.2.9 Verbosity level
43             10.2.10 Debug mode
44             10.2.11 Burst max
45             10.2.12 LED support
46             10.2.13 Max wide
47             10.2.14 Differential mode
48             10.2.15 IRQ mode
49             10.2.16 Reverse probe
50             10.2.17 Fix up PCI configuration space
51             10.2.18 Serial NVRAM
52             10.2.19 Check SCSI BUS
53             10.2.20 Exclude a host from being attached
54             10.2.21 Suggest a default SCSI id for hosts
55             10.2.22 Enable use of IMMEDIATE ARBITRATION
56      10.3 Advised boot setup commands
57      10.4 PCI configuration fix-up boot option
58      10.5 Serial NVRAM support boot option
59      10.6 SCSI BUS checking boot option
60      10.7 IMMEDIATE ARBITRATION boot option
6111. Some constants and flags of the ncr53c8xx.h header file
6212. Installation
6313. Architecture dependent features
6414. Known problems
65      14.1 Tagged commands with Iomega Jaz device
66      14.2 Device names change when another controller is added
67      14.3 Using only 8 bit devices with a WIDE SCSI controller.
68      14.4 Possible data corruption during a Memory Write and Invalidate
69      14.5 IRQ sharing problems
7015. SCSI problem troubleshooting
71      15.1 Problem tracking
72      15.2 Understanding hardware error reports
7316. Synchronous transfer negotiation tables
74      16.1 Synchronous timings for 53C875 and 53C860 Ultra-SCSI controllers
75      16.2 Synchronous timings for fast SCSI-2 53C8XX controllers
7617. Serial NVRAM support (by Richard Waltham)
77      17.1 Features
78      17.2 Symbios NVRAM layout
79      17.3 Tekram NVRAM layout
8018. Support for Big Endian
81      18.1 Big Endian CPU
82      18.2 NCR chip in Big Endian mode of operations
83
84===============================================================================
85
861. Introduction
87
88The initial Linux ncr53c8xx driver has been a port of the ncr driver from
89FreeBSD that has been achieved in November 1995 by:
90          Gerard Roudier <groudier@free.fr>
91
92The original driver has been written for 386bsd and FreeBSD by:
93          Wolfgang Stanglmeier <wolf@cologne.de>
94          Stefan Esser <se@mi.Uni-Koeln.de>
95
96It is now available as a bundle of 2 drivers:
97
98- ncr53c8xx generic driver that supports all the SYM53C8XX family including
99  the earliest 810 rev. 1, the latest 896 (2 channel LVD SCSI controller) and
100  the new 895A (1 channel LVD SCSI controller).
101- sym53c8xx enhanced driver (a.k.a. 896 drivers) that drops support of oldest
102  chips in order to gain advantage of new features, as LOAD/STORE instructions
103  available since the 810A and hardware phase mismatch available with the
104  896 and the 895A.
105
106You can find technical information about the NCR 8xx family in the
107PCI-HOWTO written by Michael Will and in the SCSI-HOWTO written by
108Drew Eckhardt.
109
110Information about new chips is available at LSILOGIC web server:
111
112          http://www.lsilogic.com/
113
114SCSI standard documentations are available at SYMBIOS ftp server:
115
116          ftp://ftp.symbios.com/
117
118Useful SCSI tools written by Eric Youngdale are available at tsx-11:
119
120          ftp://tsx-11.mit.edu/pub/linux/ALPHA/scsi/scsiinfo-X.Y.tar.gz
121          ftp://tsx-11.mit.edu/pub/linux/ALPHA/scsi/scsidev-X.Y.tar.gz
122
123These tools are not ALPHA but quite clean and work quite well.
124It is essential you have the 'scsiinfo' package.
125
126This short documentation describes the features of the generic and enhanced
127drivers, configuration parameters and control commands available through
128the proc SCSI file system read / write operations.
129
130This driver has been tested OK with linux/i386, Linux/Alpha and Linux/PPC.
131
132Latest driver version and patches are available at:
133
134          ftp://ftp.tux.org/pub/people/gerard-roudier
135or
136          ftp://ftp.symbios.com/mirror/ftp.tux.org/pub/tux/roudier/drivers
137
138I am not a native speaker of English and there are probably lots of
139mistakes in this README file. Any help will be welcome.
140
141
1422. Supported chips and SCSI features
143
144The following features are supported for all chips:
145
146    Synchronous negotiation
147    Disconnection
148    Tagged command queuing
149    SCSI parity checking
150    Master parity checking
151
152"Wide negotiation" is supported for chips that allow it. The
153following table shows some characteristics of NCR 8xx family chips
154and what drivers support them.
155
156                                                  Supported by Supported by
157       On board the generic the enhanced
158Chip SDMS BIOS Wide SCSI std. Max. sync driver driver
159---- --------- ---- --------- ---------- ------------ -------------
160810 N N FAST10 10 MB/s Y N
161810A N N FAST10 10 MB/s Y Y
162815 Y N FAST10 10 MB/s Y N
163825 Y Y FAST10 20 MB/s Y N
164825A Y Y FAST10 20 MB/s Y Y
165860 N N FAST20 20 MB/s Y Y
166875 Y Y FAST20 40 MB/s Y Y
167876 Y Y FAST20 40 MB/s Y Y
168895 Y Y FAST40 80 MB/s Y Y
169895A Y Y FAST40 80 MB/s Y Y
170896 Y Y FAST40 80 MB/s Y Y
171897 Y Y FAST40 80 MB/s Y Y
1721510D Y Y FAST40 80 MB/s Y Y
1731010 Y Y FAST80 160 MB/s N Y
1741010_66* Y Y FAST80 160 MB/s N Y
175
176* Chip supports 33MHz and 66MHz PCI buses.
177
178
179Summary of other supported features:
180
181Module: allow to load the driver
182Memory mapped I/O: increases performance
183Profiling information: read operations from the proc SCSI file system
184Control commands: write operations to the proc SCSI file system
185Debugging information: written to syslog (expert only)
186Scatter / gather
187Shared interrupt
188Boot setup commands
189Serial NVRAM: Symbios and Tekram formats
190
191
1923. Advantages of the enhanced 896 driver
193
1943.1 Optimized SCSI SCRIPTS.
195
196The 810A, 825A, 875, 895, 896 and 895A support new SCSI SCRIPTS instructions
197named LOAD and STORE that allow to move up to 1 DWORD from/to an IO register
198to/from memory much faster that the MOVE MEMORY instruction that is supported
199by the 53c7xx and 53c8xx family.
200The LOAD/STORE instructions support absolute and DSA relative addressing
201modes. The SCSI SCRIPTS had been entirely rewritten using LOAD/STORE instead
202of MOVE MEMORY instructions.
203
2043.2 New features of the SYM53C896 (64 bit PCI dual LVD SCSI controller)
205
206The 896 and the 895A allows handling of the phase mismatch context from
207SCRIPTS (avoids the phase mismatch interrupt that stops the SCSI processor
208until the C code has saved the context of the transfer).
209Implementing this without using LOAD/STORE instructions would be painful
210and I didn't even want to try it.
211
212The 896 chip supports 64 bit PCI transactions and addressing, while the
213895A supports 32 bit PCI transactions and 64 bit addressing.
214The SCRIPTS processor of these chips is not true 64 bit, but uses segment
215registers for bit 32-63. Another interesting feature is that LOAD/STORE
216instructions that address the on-chip RAM (8k) remain internal to the chip.
217
218Due to the use of LOAD/STORE SCRIPTS instructions, this driver does not
219support the following chips:
220- SYM53C810 revision < 0x10 (16)
221- SYM53C815 all revisions
222- SYM53C825 revision < 0x10 (16)
223
2244. Memory mapped I/O versus normal I/O
225
226Memory mapped I/O has less latency than normal I/O. Since
227linux-1.3.x, memory mapped I/O is used rather than normal I/O. Memory
228mapped I/O seems to work fine on most hardware configurations, but
229some poorly designed motherboards may break this feature.
230
231The configuration option CONFIG_SCSI_NCR53C8XX_IOMAPPED forces the
232driver to use normal I/O in all cases.
233
234
2355. Tagged command queueing
236
237Queuing more than 1 command at a time to a device allows it to perform
238optimizations based on actual head positions and its mechanical
239characteristics. This feature may also reduce average command latency.
240In order to really gain advantage of this feature, devices must have
241a reasonable cache size (No miracle is to be expected for a low-end
242hard disk with 128 KB or less).
243Some known SCSI devices do not properly support tagged command queuing.
244Generally, firmware revisions that fix this kind of problems are available
245at respective vendor web/ftp sites.
246All I can say is that the hard disks I use on my machines behave well with
247this driver with tagged command queuing enabled:
248
249- IBM S12 0662
250- Conner 1080S
251- Quantum Atlas I
252- Quantum Atlas II
253
254If your controller has NVRAM, you can configure this feature per target
255from the user setup tool. The Tekram Setup program allows to tune the
256maximum number of queued commands up to 32. The Symbios Setup only allows
257to enable or disable this feature.
258
259The maximum number of simultaneous tagged commands queued to a device
260is currently set to 8 by default. This value is suitable for most SCSI
261disks. With large SCSI disks (>= 2GB, cache >= 512KB, average seek time
262<= 10 ms), using a larger value may give better performances.
263
264The sym53c8xx driver supports up to 255 commands per device, and the
265generic ncr53c8xx driver supports up to 64, but using more than 32 is
266generally not worth-while, unless you are using a very large disk or disk
267array. It is noticeable that most of recent hard disks seem not to accept
268more than 64 simultaneous commands. So, using more than 64 queued commands
269is probably just resource wasting.
270
271If your controller does not have NVRAM or if it is managed by the SDMS
272BIOS/SETUP, you can configure tagged queueing feature and device queue
273depths from the boot command-line. For example:
274
275  ncr53c8xx=tags:4/t2t3q15-t4q7/t1u0q32
276
277will set tagged commands queue depths as follow:
278
279- target 2 all luns on controller 0 --> 15
280- target 3 all luns on controller 0 --> 15
281- target 4 all luns on controller 0 --> 7
282- target 1 lun 0 on controller 1 --> 32
283- all other target/lun --> 4
284
285In some special conditions, some SCSI disk firmwares may return a
286QUEUE FULL status for a SCSI command. This behaviour is managed by the
287driver using the following heuristic:
288
289- Each time a QUEUE FULL status is returned, tagged queue depth is reduced
290  to the actual number of disconnected commands.
291
292- Every 1000 successfully completed SCSI commands, if allowed by the
293  current limit, the maximum number of queueable commands is incremented.
294
295Since QUEUE FULL status reception and handling is resource wasting, the
296driver notifies by default this problem to user by indicating the actual
297number of commands used and their status, as well as its decision on the
298device queue depth change.
299The heuristic used by the driver in handling QUEUE FULL ensures that the
300impact on performances is not too bad. You can get rid of the messages by
301setting verbose level to zero, as follow:
302
3031st method: boot your system using 'ncr53c8xx=verb:0' option.
3042nd method: apply "setverbose 0" control command to the proc fs entry
305            corresponding to your controller after boot-up.
306
3076. Parity checking
308
309The driver supports SCSI parity checking and PCI bus master parity
310checking. These features must be enabled in order to ensure safe data
311transfers. However, some flawed devices or mother boards will have
312problems with parity. You can disable either PCI parity or SCSI parity
313checking by entering appropriate options from the boot command line.
314(See 10: Boot setup commands).
315
3167. Profiling information
317
318Profiling information is available through the proc SCSI file system.
319Since gathering profiling information may impact performances, this
320feature is disabled by default and requires a compilation configuration
321option to be set to Y.
322
323The device associated with a host has the following pathname:
324
325          /proc/scsi/ncr53c8xx/N (N=0,1,2 ....)
326
327Generally, only 1 board is used on hardware configuration, and that device is:
328          /proc/scsi/ncr53c8xx/0
329
330However, if the driver has been made as module, the number of the
331hosts is incremented each time the driver is loaded.
332
333In order to display profiling information, just enter:
334
335         cat /proc/scsi/ncr53c8xx/0
336
337and you will get something like the following text:
338
339-------------------------------------------------------
340General information:
341  Chip NCR53C810, device id 0x1, revision id 0x2
342  IO port address 0x6000, IRQ number 10
343  Using memory mapped IO at virtual address 0x282c000
344  Synchronous transfer period 25, max commands per lun 4
345Profiling information:
346  num_trans = 18014
347  num_kbytes = 671314
348  num_disc = 25763
349  num_break = 1673
350  num_int = 1685
351  num_fly = 18038
352  ms_setup = 4940
353  ms_data = 369940
354  ms_disc = 183090
355  ms_post = 1320
356-------------------------------------------------------
357
358General information is easy to understand. The device ID and the
359revision ID identify the SCSI chip as follows:
360
361Chip Device id Revision Id
362---- --------- -----------
363810 0x1 < 0x10
364810A 0x1 >= 0x10
365815 0x4
366825 0x3 < 0x10
367860 0x6
368825A 0x3 >= 0x10
369875 0xf
370895 0xc
371
372The profiling information is updated upon completion of SCSI commands.
373A data structure is allocated and zeroed when the host adapter is
374attached. So, if the driver is a module, the profile counters are
375cleared each time the driver is loaded. The "clearprof" command
376allows you to clear these counters at any time.
377
378The following counters are available:
379
380("num" prefix means "number of",
381"ms" means milli-seconds)
382
383num_trans
384    Number of completed commands
385    Example above: 18014 completed commands
386
387num_kbytes
388    Number of kbytes transferred
389    Example above: 671 MB transferred
390
391num_disc
392    Number of SCSI disconnections
393    Example above: 25763 SCSI disconnections
394
395num_break
396    number of script interruptions (phase mismatch)
397    Example above: 1673 script interruptions
398
399num_int
400    Number of interrupts other than "on the fly"
401    Example above: 1685 interruptions not "on the fly"
402
403num_fly
404    Number of interrupts "on the fly"
405    Example above: 18038 interruptions "on the fly"
406
407ms_setup
408    Elapsed time for SCSI commands setups
409    Example above: 4.94 seconds
410
411ms_data
412    Elapsed time for data transfers
413    Example above: 369.94 seconds spent for data transfer
414
415ms_disc
416    Elapsed time for SCSI disconnections
417    Example above: 183.09 seconds spent disconnected
418
419ms_post
420    Elapsed time for command post processing
421    (time from SCSI status get to command completion call)
422    Example above: 1.32 seconds spent for post processing
423
424Due to the 1/100 second tick of the system clock, "ms_post" time may
425be wrong.
426
427In the example above, we got 18038 interrupts "on the fly" and only
4281673 script breaks generally due to disconnections inside a segment
429of the scatter list.
430
431
4328. Control commands
433
434Control commands can be sent to the driver with write operations to
435the proc SCSI file system. The generic command syntax is the
436following:
437
438      echo "<verb> <parameters>" >/proc/scsi/ncr53c8xx/0
439      (assumes controller number is 0)
440
441Using "all" for "<target>" parameter with the commands below will
442apply to all targets of the SCSI chain (except the controller).
443
444Available commands:
445
4468.1 Set minimum synchronous period factor
447
448    setsync <target> <period factor>
449
450    target: target number
451    period: minimum synchronous period.
452               Maximum speed = 1000/(4*period factor) except for special
453               cases below.
454
455    Specify a period of 255, to force asynchronous transfer mode.
456
457      10 means 25 nano-seconds synchronous period
458      11 means 30 nano-seconds synchronous period
459      12 means 50 nano-seconds synchronous period
460
4618.2 Set wide size
462
463    setwide <target> <size>
464
465    target: target number
466    size: 0=8 bits, 1=16bits
467
4688.3 Set maximum number of concurrent tagged commands
469 
470    settags <target> <tags>
471
472    target: target number
473    tags: number of concurrent tagged commands
474               must not be greater than SCSI_NCR_MAX_TAGS (default: 8)
475
4768.4 Set order type for tagged command
477
478    setorder <order>
479
480    order: 3 possible values:
481               simple: use SIMPLE TAG for all operations (read and write)
482               ordered: use ORDERED TAG for all operations
483               default: use default tag type,
484                        SIMPLE TAG for read operations
485                        ORDERED TAG for write operations
486
487
4888.5 Set debug mode
489
490    setdebug <list of debug flags>
491
492    Available debug flags:
493        alloc: print info about memory allocations (ccb, lcb)
494        queue: print info about insertions into the command start queue
495        result: print sense data on CHECK CONDITION status
496        scatter: print info about the scatter process
497        scripts: print info about the script binding process
498    tiny: print minimal debugging information
499    timing: print timing information of the NCR chip
500    nego: print information about SCSI negotiations
501    phase: print information on script interruptions
502
503    Use "setdebug" with no argument to reset debug flags.
504
505
5068.6 Clear profile counters
507
508    clearprof
509
510    The profile counters are automatically cleared when the amount of
511    data transferred reaches 1000 GB in order to avoid overflow.
512    The "clearprof" command allows you to clear these counters at any time.
513
514
5158.7 Set flag (no_disc)
516 
517    setflag <target> <flag>
518
519    target: target number
520
521    For the moment, only one flag is available:
522
523        no_disc: not allow target to disconnect.
524
525    Do not specify any flag in order to reset the flag. For example:
526    - setflag 4
527      will reset no_disc flag for target 4, so will allow it disconnections.
528    - setflag all
529      will allow disconnection for all devices on the SCSI bus.
530
531
5328.8 Set verbose level
533
534    setverbose #level
535
536    The driver default verbose level is 1. This command allows to change
537    th driver verbose level after boot-up.
538
5398.9 Reset all logical units of a target
540
541    resetdev <target>
542
543    target: target number
544    The driver will try to send a BUS DEVICE RESET message to the target.
545    (Only supported by the SYM53C8XX driver and provided for test purpose)
546
5478.10 Abort all tasks of all logical units of a target
548
549    cleardev <target>
550
551    target: target number
552    The driver will try to send a ABORT message to all the logical units
553    of the target.
554    (Only supported by the SYM53C8XX driver and provided for test purpose)
555
556
5579. Configuration parameters
558
559If the firmware of all your devices is perfect enough, all the
560features supported by the driver can be enabled at start-up. However,
561if only one has a flaw for some SCSI feature, you can disable the
562support by the driver of this feature at linux start-up and enable
563this feature after boot-up only for devices that support it safely.
564
565CONFIG_SCSI_NCR53C8XX_IOMAPPED (default answer: n)
566    Answer "y" if you suspect your mother board to not allow memory mapped I/O.
567    May slow down performance a little. This option is required by
568    Linux/PPC and is used no matter what you select here. Linux/PPC
569    suffers no performance loss with this option since all IO is memory
570    mapped anyway.
571
572CONFIG_SCSI_NCR53C8XX_DEFAULT_TAGS (default answer: 8)
573    Default tagged command queue depth.
574
575CONFIG_SCSI_NCR53C8XX_MAX_TAGS (default answer: 8)
576    This option allows you to specify the maximum number of tagged commands
577    that can be queued to a device. The maximum supported value is 32.
578
579CONFIG_SCSI_NCR53C8XX_SYNC (default answer: 5)
580    This option allows you to specify the frequency in MHz the driver
581    will use at boot time for synchronous data transfer negotiations.
582    This frequency can be changed later with the "setsync" control command.
583    0 means "asynchronous data transfers".
584
585CONFIG_SCSI_NCR53C8XX_FORCE_SYNC_NEGO (default answer: n)
586    Force synchronous negotiation for all SCSI-2 devices.
587    Some SCSI-2 devices do not report this feature in byte 7 of inquiry
588    response but do support it properly (TAMARACK scanners for example).
589
590CONFIG_SCSI_NCR53C8XX_NO_DISCONNECT (default and only reasonable answer: n)
591    If you suspect a device of yours does not properly support disconnections,
592    you can answer "y". Then, all SCSI devices will never disconnect the bus
593    even while performing long SCSI operations.
594
595CONFIG_SCSI_NCR53C8XX_SYMBIOS_COMPAT
596    Genuine SYMBIOS boards use GPIO0 in output for controller LED and GPIO3
597    bit as a flag indicating singled-ended/differential interface.
598    If all the boards of your system are genuine SYMBIOS boards or use
599    BIOS and drivers from SYMBIOS, you would want to enable this option.
600    This option must NOT be enabled if your system has at least one 53C8XX
601    based scsi board with a vendor-specific BIOS.
602    For example, Tekram DC-390/U, DC-390/W and DC-390/F scsi controllers
603    use a vendor-specific BIOS and are known to not use SYMBIOS compatible
604    GPIO wiring. So, this option must not be enabled if your system has
605    such a board installed.
606
607CONFIG_SCSI_NCR53C8XX_NVRAM_DETECT
608    Enable support for reading the serial NVRAM data on Symbios and
609    some Symbios compatible cards, and Tekram DC390W/U/F cards. Useful for
610    systems with more than one Symbios compatible controller where at least
611    one has a serial NVRAM, or for a system with a mixture of Symbios and
612    Tekram cards. Enables setting the boot order of host adaptors
613    to something other than the default order or "reverse probe" order.
614    Also enables Symbios and Tekram cards to be distinguished so
615    CONFIG_SCSI_NCR53C8XX_SYMBIOS_COMPAT may be set in a system with a
616    mixture of Symbios and Tekram cards so the Symbios cards can make use of
617    the full range of Symbios features, differential, led pin, without
618    causing problems for the Tekram card(s).
619
62010. Boot setup commands
621
62210.1 Syntax
623
624Setup commands can be passed to the driver either at boot time or as a
625string variable using 'insmod'.
626
627A boot setup command for the ncr53c8xx (sym53c8xx) driver begins with the
628driver name "ncr53c8xx="(sym53c8xx). The kernel syntax parser then expects
629an optional list of integers separated with comma followed by an optional
630list of comma-separated strings. Example of boot setup command under lilo
631prompt:
632
633lilo: linux root=/dev/hda2 ncr53c8xx=tags:4,sync:10,debug:0x200
634
635- enable tagged commands, up to 4 tagged commands queued.
636- set synchronous negotiation speed to 10 Mega-transfers / second.
637- set DEBUG_NEGO flag.
638
639Since comma seems not to be allowed when defining a string variable using
640'insmod', the driver also accepts <space> as option separator.
641The following command will install driver module with the same options as
642above.
643
644    insmod ncr53c8xx.o ncr53c8xx="tags:4 sync:10 debug:0x200"
645
646For the moment, the integer list of arguments is discarded by the driver.
647It will be used in the future in order to allow a per controller setup.
648
649Each string argument must be specified as "keyword:value". Only lower-case
650characters and digits are allowed.
651
652In a system that contains multiple 53C8xx adapters insmod will install the
653specified driver on each adapter. To exclude a chip use the 'excl' keyword.
654
655The sequence of commands,
656
657    insmod sym53c8xx sym53c8xx=excl:0x1400
658    insmod ncr53c8xx
659
660installs the sym53c8xx driver on all adapters except the one at IO port
661address 0x1400 and then installs the ncr53c8xx driver to the adapter at IO
662port address 0x1400.
663
664
66510.2 Available arguments
666
66710.2.1 Master parity checking
668        mpar:y enabled
669        mpar:n disabled
670
67110.2.2 Scsi parity checking
672        spar:y enabled
673        spar:n disabled
674
67510.2.3 Scsi disconnections
676        disc:y enabled
677        disc:n disabled
678 
67910.2.4 Special features
680   Only apply to 810A, 825A, 860, 875 and 895 controllers.
681   Have no effect with other ones.
682        specf:y (or 1) enabled
683        specf:n (or 0) disabled
684        specf:3 enabled except Memory Write And Invalidate
685   The default driver setup is 'specf:3'. As a consequence, option 'specf:y'
686   must be specified in the boot setup command to enable Memory Write And
687   Invalidate.
688
68910.2.5 Ultra SCSI support
690   Only apply to 860, 875, 895, 895a, 896, 1010 and 1010_66 controllers.
691   Have no effect with other ones.
692        ultra:n All ultra speeds enabled
693        ultra:2 Ultra2 enabled
694        ultra:1 Ultra enabled
695        ultra:0 Ultra speeds disabled
696
69710.2.6 Default number of tagged commands
698        tags:0 (or tags:1 ) tagged command queuing disabled
699        tags:#tags (#tags > 1) tagged command queuing enabled
700  #tags will be truncated to the max queued commands configuration parameter.
701  This option also allows to specify a command queue depth for each device
702  that support tagged command queueing.
703  Example:
704      ncr53c8xx=tags:10/t2t3q16-t5q24/t1u2q32
705               will set devices queue depth as follow:
706      - controller #0 target #2 and target #3 -> 16 commands,
707      - controller #0 target #5 -> 24 commands,
708      - controller #1 target #1 logical unit #2 -> 32 commands,
709      - all other logical units (all targets, all controllers) -> 10 commands.
710
71110.2.7 Default synchronous period factor
712        sync:255 disabled (asynchronous transfer mode)
713        sync:#factor
714  #factor = 10 Ultra-2 SCSI 40 Mega-transfers / second
715  #factor = 11 Ultra-2 SCSI 33 Mega-transfers / second
716  #factor < 25 Ultra SCSI 20 Mega-transfers / second
717  #factor < 50 Fast SCSI-2
718
719  In all cases, the driver will use the minimum transfer period supported by
720  controllers according to NCR53C8XX chip type.
721
72210.2.8 Negotiate synchronous with all devices
723        (force sync nego)
724        fsn:y enabled
725        fsn:n disabled
726
72710.2.9 Verbosity level
728        verb:0 minimal
729        verb:1 normal
730        verb:2 too much
731
73210.2.10 Debug mode
733        debug:0 clear debug flags
734        debug:#x set debug flags
735  #x is an integer value combining the following power-of-2 values:
736  DEBUG_ALLOC 0x1
737  DEBUG_PHASE 0x2
738  DEBUG_POLL 0x4
739  DEBUG_QUEUE 0x8
740  DEBUG_RESULT 0x10
741  DEBUG_SCATTER 0x20
742  DEBUG_SCRIPT 0x40
743  DEBUG_TINY 0x80
744  DEBUG_TIMING 0x100
745  DEBUG_NEGO 0x200
746  DEBUG_TAGS 0x400
747  DEBUG_FREEZE 0x800
748  DEBUG_RESTART 0x1000
749
750  You can play safely with DEBUG_NEGO. However, some of these flags may
751  generate bunches of syslog messages.
752
75310.2.11 Burst max
754        burst:0 burst disabled
755        burst:255 get burst length from initial IO register settings.
756        burst:#x burst enabled (1<<#x burst transfers max)
757  #x is an integer value which is log base 2 of the burst transfers max.
758  The NCR53C875 and NCR53C825A support up to 128 burst transfers (#x = 7).
759  Other chips only support up to 16 (#x = 4).
760  This is a maximum value. The driver set the burst length according to chip
761  and revision ids. By default the driver uses the maximum value supported
762  by the chip.
763
76410.2.12 LED support
765        led:1 enable LED support
766        led:0 disable LED support
767  Donnot enable LED support if your scsi board does not use SDMS BIOS.
768  (See 'Configuration parameters')
769
77010.2.13 Max wide
771        wide:1 wide scsi enabled
772        wide:0 wide scsi disabled
773  Some scsi boards use a 875 (ultra wide) and only supply narrow connectors.
774  If you have connected a wide device with a 50 pins to 68 pins cable
775  converter, any accepted wide negotiation will break further data transfers.
776  In such a case, using "wide:0" in the bootup command will be helpful.
777
77810.2.14 Differential mode
779        diff:0 never set up diff mode
780        diff:1 set up diff mode if BIOS set it
781        diff:2 always set up diff mode
782        diff:3 set diff mode if GPIO3 is not set
783
78410.2.15 IRQ mode
785        irqm:0 always open drain
786        irqm:1 same as initial settings (assumed BIOS settings)
787        irqm:2 always totem pole
788        irqm:0x10 driver will not use IRQF_SHARED flag when requesting irq
789        irqm:0x20 driver will not use IRQF_DISABLED flag when requesting irq
790
791    (Bits 0x10 and 0x20 can be combined with hardware irq mode option)
792
79310.2.16 Reverse probe
794        revprob:n probe chip ids from the PCI configuration in this order:
795                    810, 815, 820, 860, 875, 885, 895, 896
796        revprob:y probe chip ids in the reverse order.
797
79810.2.17 Fix up PCI configuration space
799        pcifix:<option bits>
800
801    Available option bits:
802        0x0: No attempt to fix PCI configuration space registers values.
803        0x1: Set PCI cache-line size register if not set.
804        0x2: Set write and invalidate bit in PCI command register.
805        0x4: Increase if necessary PCI latency timer according to burst max.
806
807    Use 'pcifix:7' in order to allow the driver to fix up all PCI features.
808
80910.2.18 Serial NVRAM
810        nvram:n do not look for serial NVRAM
811        nvram:y test controllers for onboard serial NVRAM
812        (alternate binary form)
813        mvram=<bits options>
814        0x01 look for NVRAM (equivalent to nvram=y)
815        0x02 ignore NVRAM "Synchronous negotiation" parameters for all devices
816        0x04 ignore NVRAM "Wide negotiation" parameter for all devices
817        0x08 ignore NVRAM "Scan at boot time" parameter for all devices
818        0x80 also attach controllers set to OFF in the NVRAM (sym53c8xx only)
819
82010.2.19 Check SCSI BUS
821        buschk:<option bits>
822
823    Available option bits:
824        0x0: No check.
825        0x1: Check and do not attach the controller on error.
826        0x2: Check and just warn on error.
827        0x4: Disable SCSI bus integrity checking.
828
82910.2.20 Exclude a host from being attached
830        excl=<io_address>
831
832    Prevent host at a given io address from being attached.
833    For example 'ncr53c8xx=excl:0xb400,excl:0xc000' indicate to the
834    ncr53c8xx driver not to attach hosts at address 0xb400 and 0xc000.
835
83610.2.21 Suggest a default SCSI id for hosts
837        hostid:255 no id suggested.
838        hostid:#x (0 < x < 7) x suggested for hosts SCSI id.
839
840    If a host SCSI id is available from the NVRAM, the driver will ignore
841    any value suggested as boot option. Otherwise, if a suggested value
842    different from 255 has been supplied, it will use it. Otherwise, it will
843    try to deduce the value previously set in the hardware and use value
844    7 if the hardware value is zero.
845
84610.2.22 Enable use of IMMEDIATE ARBITRATION
847        (only supported by the sym53c8xx driver. See 10.7 for more details)
848        iarb:0 do not use this feature.
849        iarb:#x use this feature according to bit fields as follow:
850
851    bit 0 (1) : enable IARB each time the initiator has been reselected
852                when it arbitrated for the SCSI BUS.
853    (#x >> 4) : maximum number of successive settings of IARB if the initiator
854                win arbitration and it has other commands to send to a device.
855
856Boot fail safe
857    safe:y load the following assumed fail safe initial setup
858
859  master parity disabled mpar:n
860  scsi parity enabled spar:y
861  disconnections not allowed disc:n
862  special features disabled specf:n
863  ultra scsi disabled ultra:n
864  force sync negotiation disabled fsn:n
865  reverse probe disabled revprob:n
866  PCI fix up disabled pcifix:0
867  serial NVRAM enabled nvram:y
868  verbosity level 2 verb:2
869  tagged command queuing disabled tags:0
870  synchronous negotiation disabled sync:255
871  debug flags none debug:0
872  burst length from BIOS settings burst:255
873  LED support disabled led:0
874  wide support disabled wide:0
875  settle time 10 seconds settle:10
876  differential support from BIOS settings diff:1
877  irq mode from BIOS settings irqm:1
878  SCSI BUS check do not attach on error buschk:1
879  immediate arbitration disabled iarb:0
880
88110.3 Advised boot setup commands
882
883If the driver has been configured with default options, the equivalent
884boot setup is:
885
886   ncr53c8xx=mpar:y,spar:y,disc:y,specf:3,fsn:n,ultra:2,fsn:n,revprob:n,verb:1\
887             tags:0,sync:50,debug:0,burst:7,led:0,wide:1,settle:2,diff:0,irqm:0
888
889For an installation diskette or a safe but not fast system,
890boot setup can be:
891
892    ncr53c8xx=safe:y,mpar:y,disc:y
893    ncr53c8xx=safe:y,disc:y
894    ncr53c8xx=safe:y,mpar:y
895    ncr53c8xx=safe:y
896
897My personal system works flawlessly with the following equivalent setup:
898
899   ncr53c8xx=mpar:y,spar:y,disc:y,specf:1,fsn:n,ultra:2,fsn:n,revprob:n,verb:1\
900             tags:32,sync:12,debug:0,burst:7,led:1,wide:1,settle:2,diff:0,irqm:0
901
902The driver prints its actual setup when verbosity level is 2. You can try
903"ncr53c8xx=verb:2" to get the "static" setup of the driver, or add "verb:2"
904to your boot setup command in order to check the actual setup the driver is
905using.
906
90710.4 PCI configuration fix-up boot option
908
909pcifix:<option bits>
910
911Available option bits:
912    0x1: Set PCI cache-line size register if not set.
913    0x2: Set write and invalidate bit in PCI command register.
914
915Use 'pcifix:3' in order to allow the driver to fix both PCI features.
916
917These options only apply to new SYMBIOS chips 810A, 825A, 860, 875
918and 895 and are only supported for Pentium and 486 class processors.
919Recent SYMBIOS 53C8XX scsi processors are able to use PCI read multiple
920and PCI write and invalidate commands. These features require the
921cache line size register to be properly set in the PCI configuration
922space of the chips. On the other hand, chips will use PCI write and
923invalidate commands only if the corresponding bit is set to 1 in the
924PCI command register.
925
926Not all PCI bioses set the PCI cache line register and the PCI write and
927invalidate bit in the PCI configuration space of 53C8XX chips.
928Optimized PCI accesses may be broken for some PCI/memory controllers or
929make problems with some PCI boards.
930
931This fix-up worked flawlessly on my previous system.
932(MB Triton HX / 53C875 / 53C810A)
933I use these options at my own risks as you will do if you decide to
934use them too.
935
936
93710.5 Serial NVRAM support boot option
938
939nvram:n do not look for serial NVRAM
940nvram:y test controllers for onboard serial NVRAM
941
942This option can also been entered as an hexadecimal value that allows
943to control what information the driver will get from the NVRAM and what
944information it will ignore.
945For details see '17. Serial NVRAM support'.
946
947When this option is enabled, the driver tries to detect all boards using
948a Serial NVRAM. This memory is used to hold user set up parameters.
949
950The parameters the driver is able to get from the NVRAM depend on the
951data format used, as follow:
952
953                                 Tekram format Symbios format
954General and host parameters
955    Boot order N Y
956    Host SCSI ID Y Y
957    SCSI parity checking Y Y
958    Verbose boot messages N Y
959SCSI devices parameters
960    Synchronous transfer speed Y Y
961    Wide 16 / Narrow Y Y
962    Tagged Command Queuing enabled Y Y
963    Disconnections enabled Y Y
964    Scan at boot time N Y
965
966In order to speed up the system boot, for each device configured without
967the "scan at boot time" option, the driver forces an error on the
968first TEST UNIT READY command received for this device.
969
970Some SDMS BIOS revisions seem to be unable to boot cleanly with very fast
971hard disks. In such a situation you cannot configure the NVRAM with
972optimized parameters value.
973
974The 'nvram' boot option can be entered in hexadecimal form in order
975to ignore some options configured in the NVRAM, as follow:
976
977mvram=<bits options>
978      0x01 look for NVRAM (equivalent to nvram=y)
979      0x02 ignore NVRAM "Synchronous negotiation" parameters for all devices
980      0x04 ignore NVRAM "Wide negotiation" parameter for all devices
981      0x08 ignore NVRAM "Scan at boot time" parameter for all devices
982      0x80 also attach controllers set to OFF in the NVRAM (sym53c8xx only)
983
984Option 0x80 is only supported by the sym53c8xx driver and is disabled by
985default. Result is that, by default (option not set), the sym53c8xx driver
986will not attach controllers set to OFF in the NVRAM.
987
988The ncr53c8xx always tries to attach all the controllers. Option 0x80 has
989not been added to the ncr53c8xx driver, since it has been reported to
990confuse users who use this driver since a long time. If you desire a
991controller not to be attached by the ncr53c8xx driver at Linux boot, you
992must use the 'excl' driver boot option.
993
99410.6 SCSI BUS checking boot option.
995
996When this option is set to a non-zero value, the driver checks SCSI lines
997logic state, 100 micro-seconds after having asserted the SCSI RESET line.
998The driver just reads SCSI lines and checks all lines read FALSE except RESET.
999Since SCSI devices shall release the BUS at most 800 nano-seconds after SCSI
1000RESET has been asserted, any signal to TRUE may indicate a SCSI BUS problem.
1001Unfortunately, the following common SCSI BUS problems are not detected:
1002- Only 1 terminator installed.
1003- Misplaced terminators.
1004- Bad quality terminators.
1005On the other hand, either bad cabling, broken devices, not conformant
1006devices, ... may cause a SCSI signal to be wrong when te driver reads it.
1007
100810.7 IMMEDIATE ARBITRATION boot option
1009
1010This option is only supported by the SYM53C8XX driver (not by the NCR53C8XX).
1011
1012SYMBIOS 53C8XX chips are able to arbitrate for the SCSI BUS as soon as they
1013have detected an expected disconnection (BUS FREE PHASE). For this process
1014to be started, bit 1 of SCNTL1 IO register must be set when the chip is
1015connected to the SCSI BUS.
1016
1017When this feature has been enabled for the current connection, the chip has
1018every chance to win arbitration if only devices with lower priority are
1019competing for the SCSI BUS. By the way, when the chip is using SCSI id 7,
1020then it will for sure win the next SCSI BUS arbitration.
1021
1022Since, there is no way to know what devices are trying to arbitrate for the
1023BUS, using this feature can be extremely unfair. So, you are not advised
1024to enable it, or at most enable this feature for the case the chip lost
1025the previous arbitration (boot option 'iarb:1').
1026
1027This feature has the following advantages:
1028
1029a) Allow the initiator with ID 7 to win arbitration when it wants so.
1030b) Overlap at least 4 micro-seconds of arbitration time with the execution
1031   of SCRIPTS that deal with the end of the current connection and that
1032   starts the next job.
1033
1034Hmmm... But (a) may just prevent other devices from reselecting the initiator,
1035and delay data transfers or status/completions, and (b) may just waste
1036SCSI BUS bandwidth if the SCRIPTS execution lasts more than 4 micro-seconds.
1037
1038The use of IARB needs the SCSI_NCR_IARB_SUPPORT option to have been defined
1039at compile time and the 'iarb' boot option to have been set to a non zero
1040value at boot time. It is not that useful for real work, but can be used
1041to stress SCSI devices or for some applications that can gain advantage of
1042it. By the way, if you experience badnesses like 'unexpected disconnections',
1043'bad reselections', etc... when using IARB on heavy IO load, you should not
1044be surprised, because force-feeding anything and blocking its arse at the
1045same time cannot work for a long time. :-))
1046
1047
104811. Some constants and flags of the ncr53c8xx.h header file
1049
1050Some of these are defined from the configuration parameters. To
1051change other "defines", you must edit the header file. Do that only
1052if you know what you are doing.
1053
1054SCSI_NCR_SETUP_SPECIAL_FEATURES (default: defined)
1055    If defined, the driver will enable some special features according
1056    to chip and revision id.
1057        For 810A, 860, 825A, 875 and 895 scsi chips, this option enables
1058    support of features that reduce load of PCI bus and memory accesses
1059    during scsi transfer processing: burst op-code fetch, read multiple,
1060        read line, prefetch, cache line, write and invalidate,
1061        burst 128 (875 only), large dma fifo (875 only), offset 16 (875 only).
1062    Can be changed by the following boot setup command:
1063        ncr53c8xx=specf:n
1064
1065SCSI_NCR_IOMAPPED (default: not defined)
1066    If defined, normal I/O is forced.
1067
1068SCSI_NCR_SHARE_IRQ (default: defined)
1069    If defined, request shared IRQ.
1070    
1071SCSI_NCR_MAX_TAGS (default: 8)
1072    Maximum number of simultaneous tagged commands to a device.
1073    Can be changed by "settags <target> <maxtags>"
1074
1075SCSI_NCR_SETUP_DEFAULT_SYNC (default: 50)
1076    Transfer period factor the driver will use at boot time for synchronous
1077    negotiation. 0 means asynchronous.
1078    Can be changed by "setsync <target> <period factor>"
1079
1080SCSI_NCR_SETUP_DEFAULT_TAGS (default: 8)
1081    Default number of simultaneous tagged commands to a device.
1082    < 1 means tagged command queuing disabled at start-up.
1083
1084SCSI_NCR_ALWAYS_SIMPLE_TAG (default: defined)
1085    Use SIMPLE TAG for read and write commands.
1086    Can be changed by "setorder <ordered|simple|default>"
1087
1088SCSI_NCR_SETUP_DISCONNECTION (default: defined)
1089    If defined, targets are allowed to disconnect.
1090
1091SCSI_NCR_SETUP_FORCE_SYNC_NEGO (default: not defined)
1092    If defined, synchronous negotiation is tried for all SCSI-2 devices.
1093    Can be changed by "setsync <target> <period>"
1094
1095SCSI_NCR_SETUP_MASTER_PARITY (default: defined)
1096    If defined, master parity checking is enabled.
1097
1098SCSI_NCR_SETUP_MASTER_PARITY (default: defined)
1099    If defined, SCSI parity checking is enabled.
1100
1101SCSI_NCR_PROFILE_SUPPORT (default: not defined)
1102    If defined, profiling information is gathered.
1103
1104SCSI_NCR_MAX_SCATTER (default: 128)
1105    Scatter list size of the driver ccb.
1106
1107SCSI_NCR_MAX_TARGET (default: 16)
1108    Max number of targets per host.
1109
1110SCSI_NCR_MAX_HOST (default: 2)
1111    Max number of host controllers.
1112
1113SCSI_NCR_SETTLE_TIME (default: 2)
1114    Number of seconds the driver will wait after reset.
1115
1116SCSI_NCR_TIMEOUT_ALERT (default: 3)
1117    If a pending command will time out after this amount of seconds,
1118    an ordered tag is used for the next command.
1119    Avoids timeouts for unordered tagged commands.
1120
1121SCSI_NCR_CAN_QUEUE (default: 7*SCSI_NCR_MAX_TAGS)
1122    Max number of commands that can be queued to a host.
1123
1124SCSI_NCR_CMD_PER_LUN (default: SCSI_NCR_MAX_TAGS)
1125    Max number of commands queued to a host for a device.
1126
1127SCSI_NCR_SG_TABLESIZE (default: SCSI_NCR_MAX_SCATTER-1)
1128    Max size of the Linux scatter/gather list.
1129
1130SCSI_NCR_MAX_LUN (default: 8)
1131    Max number of LUNs per target.
1132
1133
113412. Installation
1135
1136This driver is part of the linux kernel distribution.
1137Driver files are located in the sub-directory "drivers/scsi" of the
1138kernel source tree.
1139
1140Driver files:
1141
1142    README.ncr53c8xx : this file
1143    ChangeLog.ncr53c8xx : change log
1144    ncr53c8xx.h : definitions
1145    ncr53c8xx.c : the driver code
1146
1147New driver versions are made available separately in order to allow testing
1148changes and new features prior to including them into the linux kernel
1149distribution. The following URL provides information on latest available
1150patches:
1151
1152      ftp://ftp.tux.org/pub/people/gerard-roudier/README
1153
1154
115513. Architecture dependent features.
1156
1157<Not yet written>
1158
1159
116014. Known problems
1161
116214.1 Tagged commands with Iomega Jaz device
1163
1164I have not tried this device, however it has been reported to me the
1165following: This device is capable of Tagged command queuing. However
1166while spinning up, it rejects Tagged commands. This behaviour is
1167conforms to 6.8.2 of SCSI-2 specifications. The current behaviour of
1168the driver in that situation is not satisfying. So do not enable
1169Tagged command queuing for devices that are able to spin down. The
1170other problem that may appear is timeouts. The only way to avoid
1171timeouts seems to edit linux/drivers/scsi/sd.c and to increase the
1172current timeout values.
1173
117414.2 Device names change when another controller is added.
1175
1176When you add a new NCR53C8XX chip based controller to a system that already
1177has one or more controllers of this family, it may happen that the order
1178the driver registers them to the kernel causes problems due to device
1179name changes.
1180When at least one controller uses NvRAM, SDMS BIOS version 4 allows you to
1181define the order the BIOS will scan the scsi boards. The driver attaches
1182controllers according to BIOS information if NvRAM detect option is set.
1183
1184If your controllers do not have NvRAM, you can:
1185
1186- Ask the driver to probe chip ids in reverse order from the boot command
1187  line: ncr53c8xx=revprob:y
1188- Make appropriate changes in the fstab.
1189- Use the 'scsidev' tool from Eric Youngdale.
1190
119114.3 Using only 8 bit devices with a WIDE SCSI controller.
1192
1193When only 8 bit NARROW devices are connected to a 16 bit WIDE SCSI controller,
1194you must ensure that lines of the wide part of the SCSI BUS are pulled-up.
1195This can be achieved by ENABLING the WIDE TERMINATOR portion of the SCSI
1196controller card.
1197The TYAN 1365 documentation revision 1.2 is not correct about such settings.
1198(page 10, figure 3.3).
1199
120014.4 Possible data corruption during a Memory Write and Invalidate
1201
1202This problem is described in SYMBIOS DEL 397, Part Number 69-039241, ITEM 4.
1203
1204In some complex situations, 53C875 chips revision <= 3 may start a PCI
1205Write and Invalidate Command at a not cache-line-aligned 4 DWORDS boundary.
1206This is only possible when Cache Line Size is 8 DWORDS or greater.
1207Pentium systems use a 8 DWORDS cache line size and so are concerned by
1208this chip bug, unlike i486 systems that use a 4 DWORDS cache line size.
1209
1210When this situation occurs, the chip may complete the Write and Invalidate
1211command after having only filled part of the last cache line involved in
1212the transfer, leaving to data corruption the remainder of this cache line.
1213
1214Not using Write And Invalidate obviously gets rid of this chip bug, and so
1215it is now the default setting of the driver.
1216However, for people like me who want to enable this feature, I have added
1217part of a work-around suggested by SYMBIOS. This work-around resets the
1218addressing logic when the DATA IN phase is entered and so prevents the bug
1219from being triggered for the first SCSI MOVE of the phase. This work-around
1220should be enough according to the following:
1221
1222The only driver internal data structure that is greater than 8 DWORDS and
1223that is moved by the SCRIPTS processor is the 'CCB header' that contains
1224the context of the SCSI transfer. This data structure is aligned on 8 DWORDS
1225boundary (Pentium Cache Line Size), and so is immune to this chip bug, at
1226least on Pentium systems.
1227But the conditions of this bug can be met when a SCSI read command is
1228performed using a buffer that is 4 DWORDS but not cache-line aligned.
1229This cannot happen under Linux when scatter/gather lists are used since
1230they only refer to system buffers that are well aligned. So, a work around
1231may only be needed under Linux when a scatter/gather list is not used and
1232when the SCSI DATA IN phase is reentered after a phase mismatch.
1233
123414.5 IRQ sharing problems
1235
1236When an IRQ is shared by devices that are handled by different drivers, it
1237may happen that one driver complains about the request of the IRQ having
1238failed. Inder Linux-2.0, this may be due to one driver having requested the
1239IRQ using the IRQF_DISABLED flag but some other having requested the same IRQ
1240without this flag. Under both Linux-2.0 and linux-2.2, this may be caused by
1241one driver not having requested the IRQ with the IRQF_SHARED flag.
1242
1243By default, the ncr53c8xx and sym53c8xx drivers request IRQs with both the
1244IRQF_DISABLED and the IRQF_SHARED flag under Linux-2.0 and with only the IRQF_SHARED
1245flag under Linux-2.2.
1246
1247Under Linux-2.0, you can disable use of IRQF_DISABLED flag from the boot
1248command line by using the following option:
1249
1250     ncr53c8xx=irqm:0x20 (for the generic ncr53c8xx driver)
1251     sym53c8xx=irqm:0x20 (for the sym53c8xx driver)
1252
1253If this does not fix the problem, then you may want to check how all other
1254drivers are requesting the IRQ and report the problem. Note that if at least
1255a single driver does not request the IRQ with the IRQF_SHARED flag (share IRQ),
1256then the request of the IRQ obviously will not succeed for all the drivers.
1257
125815. SCSI problem troubleshooting
1259
126015.1 Problem tracking
1261
1262Most SCSI problems are due to a non conformant SCSI bus or to buggy
1263devices. If unfortunately you have SCSI problems, you can check the
1264following things:
1265
1266- SCSI bus cables
1267- terminations at both end of the SCSI chain
1268- linux syslog messages (some of them may help you)
1269
1270If you do not find the source of problems, you can configure the
1271driver with no features enabled.
1272
1273- only asynchronous data transfers
1274- tagged commands disabled
1275- disconnections not allowed
1276
1277Now, if your SCSI bus is ok, your system have every chance to work
1278with this safe configuration but performances will not be optimal.
1279
1280If it still fails, then you can send your problem description to
1281appropriate mailing lists or news-groups. Send me a copy in order to
1282be sure I will receive it. Obviously, a bug in the driver code is
1283possible.
1284
1285     My email address: Gerard Roudier <groudier@free.fr>
1286
1287Allowing disconnections is important if you use several devices on
1288your SCSI bus but often causes problems with buggy devices.
1289Synchronous data transfers increases throughput of fast devices like
1290hard disks. Good SCSI hard disks with a large cache gain advantage of
1291tagged commands queuing.
1292
1293Try to enable one feature at a time with control commands. For example:
1294
1295- echo "setsync all 25" >/proc/scsi/ncr53c8xx/0
1296  Will enable fast synchronous data transfer negotiation for all targets.
1297
1298- echo "setflag 3" >/proc/scsi/ncr53c8xx/0
1299  Will reset flags (no_disc) for target 3, and so will allow it to disconnect
1300  the SCSI Bus.
1301
1302- echo "settags 3 8" >/proc/scsi/ncr53c8xx/0
1303  Will enable tagged command queuing for target 3 if that device supports it.
1304
1305Once you have found the device and the feature that cause problems, just
1306disable that feature for that device.
1307
130815.2 Understanding hardware error reports
1309
1310When the driver detects an unexpected error condition, it may display a
1311message of the following pattern.
1312
1313sym53c876-0:1: ERROR (0:48) (1-21-65) (f/95) @ (script 7c0:19000000).
1314sym53c876-0: script cmd = 19000000
1315sym53c876-0: regdump: da 10 80 95 47 0f 01 07 75 01 81 21 80 01 09 00.
1316
1317Some fields in such a message may help you understand the cause of the
1318problem, as follows:
1319
1320sym53c876-0:1: ERROR (0:48) (1-21-65) (f/95) @ (script 7c0:19000000).
1321............A.........B.C....D.E..F....G.H.......I.....J...K.......
1322
1323Field A : target number.
1324  SCSI ID of the device the controller was talking with at the moment the
1325  error occurs.
1326
1327Field B : DSTAT io register (DMA STATUS)
1328  Bit 0x40 : MDPE Master Data Parity Error
1329             Data parity error detected on the PCI BUS.
1330  Bit 0x20 : BF Bus Fault
1331             PCI bus fault condition detected
1332  Bit 0x01 : IID Illegal Instruction Detected
1333             Set by the chip when it detects an Illegal Instruction format
1334             on some condition that makes an instruction illegal.
1335  Bit 0x80 : DFE Dma Fifo Empty
1336             Pure status bit that does not indicate an error.
1337  If the reported DSTAT value contains a combination of MDPE (0x40),
1338  BF (0x20), then the cause may be likely due to a PCI BUS problem.
1339
1340Field C : SIST io register (SCSI Interrupt Status)
1341  Bit 0x08 : SGE SCSI GROSS ERROR
1342             Indicates that the chip detected a severe error condition
1343             on the SCSI BUS that prevents the SCSI protocol from functioning
1344             properly.
1345  Bit 0x04 : UDC Unexpected Disconnection
1346             Indicates that the device released the SCSI BUS when the chip
1347             was not expecting this to happen. A device may behave so to
1348             indicate the SCSI initiator that an error condition not reportable using the SCSI protocol has occurred.
1349  Bit 0x02 : RST SCSI BUS Reset
1350             Generally SCSI targets do not reset the SCSI BUS, although any
1351             device on the BUS can reset it at any time.
1352  Bit 0x01 : PAR Parity
1353             SCSI parity error detected.
1354  On a faulty SCSI BUS, any error condition among SGE (0x08), UDC (0x04) and
1355  PAR (0x01) may be detected by the chip. If your SCSI system sometimes
1356  encounters such error conditions, especially SCSI GROSS ERROR, then a SCSI
1357  BUS problem is likely the cause of these errors.
1358
1359For fields D,E,F,G and H, you may look into the sym53c8xx_defs.h file
1360that contains some minimal comments on IO register bits.
1361Field D : SOCL Scsi Output Control Latch
1362          This register reflects the state of the SCSI control lines the
1363          chip want to drive or compare against.
1364Field E : SBCL Scsi Bus Control Lines
1365          Actual value of control lines on the SCSI BUS.
1366Field F : SBDL Scsi Bus Data Lines
1367          Actual value of data lines on the SCSI BUS.
1368Field G : SXFER SCSI Transfer
1369          Contains the setting of the Synchronous Period for output and
1370          the current Synchronous offset (offset 0 means asynchronous).
1371Field H : SCNTL3 Scsi Control Register 3
1372          Contains the setting of timing values for both asynchronous and
1373          synchronous data transfers.
1374
1375Understanding Fields I, J, K and dumps requires to have good knowledge of
1376SCSI standards, chip cores functionnals and internal driver data structures.
1377You are not required to decode and understand them, unless you want to help
1378maintain the driver code.
1379
138016. Synchronous transfer negotiation tables
1381
1382Tables below have been created by calling the routine the driver uses
1383for synchronisation negotiation timing calculation and chip setting.
1384The first table corresponds to Ultra chips 53875 and 53C860 with 80 MHz
1385clock and 5 clock divisors.
1386The second one has been calculated by setting the scsi clock to 40 Mhz
1387and using 4 clock divisors and so applies to all NCR53C8XX chips in fast
1388SCSI-2 mode.
1389
1390Periods are in nano-seconds and speeds are in Mega-transfers per second.
13911 Mega-transfers/second means 1 MB/s with 8 bits SCSI and 2 MB/s with
1392Wide16 SCSI.
1393
139416.1 Synchronous timings for 53C895, 53C875 and 53C860 SCSI controllers
1395
1396 ----------------------------------------------
1397 Negotiated NCR settings
1398 Factor Period Speed Period Speed
1399 ------ ------ ------ ------ ------
1400 10 25 40.000 25 40.000 (53C895 only)
1401 11 30.2 33.112 31.25 32.000 (53C895 only)
1402 12 50 20.000 50 20.000
1403 13 52 19.230 62 16.000
1404 14 56 17.857 62 16.000
1405 15 60 16.666 62 16.000
1406 16 64 15.625 75 13.333
1407 17 68 14.705 75 13.333
1408 18 72 13.888 75 13.333
1409 19 76 13.157 87 11.428
1410 20 80 12.500 87 11.428
1411 21 84 11.904 87 11.428
1412 22 88 11.363 93 10.666
1413 23 92 10.869 93 10.666
1414 24 96 10.416 100 10.000
1415 25 100 10.000 100 10.000
1416 26 104 9.615 112 8.888
1417 27 108 9.259 112 8.888
1418 28 112 8.928 112 8.888
1419 29 116 8.620 125 8.000
1420 30 120 8.333 125 8.000
1421 31 124 8.064 125 8.000
1422 32 128 7.812 131 7.619
1423 33 132 7.575 150 6.666
1424 34 136 7.352 150 6.666
1425 35 140 7.142 150 6.666
1426 36 144 6.944 150 6.666
1427 37 148 6.756 150 6.666
1428 38 152 6.578 175 5.714
1429 39 156 6.410 175 5.714
1430 40 160 6.250 175 5.714
1431 41 164 6.097 175 5.714
1432 42 168 5.952 175 5.714
1433 43 172 5.813 175 5.714
1434 44 176 5.681 187 5.333
1435 45 180 5.555 187 5.333
1436 46 184 5.434 187 5.333
1437 47 188 5.319 200 5.000
1438 48 192 5.208 200 5.000
1439 49 196 5.102 200 5.000
1440
1441
144216.2 Synchronous timings for fast SCSI-2 53C8XX controllers
1443
1444 ----------------------------------------------
1445 Negotiated NCR settings
1446 Factor Period Speed Period Speed
1447 ------ ------ ------ ------ ------
1448 25 100 10.000 100 10.000
1449 26 104 9.615 125 8.000
1450 27 108 9.259 125 8.000
1451 28 112 8.928 125 8.000
1452 29 116 8.620 125 8.000
1453 30 120 8.333 125 8.000
1454 31 124 8.064 125 8.000
1455 32 128 7.812 131 7.619
1456 33 132 7.575 150 6.666
1457 34 136 7.352 150 6.666
1458 35 140 7.142 150 6.666
1459 36 144 6.944 150 6.666
1460 37 148 6.756 150 6.666
1461 38 152 6.578 175 5.714
1462 39 156 6.410 175 5.714
1463 40 160 6.250 175 5.714
1464 41 164 6.097 175 5.714
1465 42 168 5.952 175 5.714
1466 43 172 5.813 175 5.714
1467 44 176 5.681 187 5.333
1468 45 180 5.555 187 5.333
1469 46 184 5.434 187 5.333
1470 47 188 5.319 200 5.000
1471 48 192 5.208 200 5.000
1472 49 196 5.102 200 5.000
1473
1474
147517. Serial NVRAM (added by Richard Waltham: dormouse@farsrobt.demon.co.uk)
1476
147717.1 Features
1478
1479Enabling serial NVRAM support enables detection of the serial NVRAM included
1480on Symbios and some Symbios compatible host adaptors, and Tekram boards. The
1481serial NVRAM is used by Symbios and Tekram to hold set up parameters for the
1482host adaptor and its attached drives.
1483
1484The Symbios NVRAM also holds data on the boot order of host adaptors in a
1485system with more than one host adaptor. This enables the order of scanning
1486the cards for drives to be changed from the default used during host adaptor
1487detection.
1488
1489This can be done to a limited extent at the moment using "reverse probe" but
1490this only changes the order of detection of different types of cards. The
1491NVRAM boot order settings can do this as well as change the order the same
1492types of cards are scanned in, something "reverse probe" cannot do.
1493
1494Tekram boards using Symbios chips, DC390W/F/U, which have NVRAM are detected
1495and this is used to distinguish between Symbios compatible and Tekram host
1496adaptors. This is used to disable the Symbios compatible "diff" setting
1497incorrectly set on Tekram boards if the CONFIG_SCSI_53C8XX_SYMBIOS_COMPAT
1498configuration parameter is set enabling both Symbios and Tekram boards to be
1499used together with the Symbios cards using all their features, including
1500"diff" support. ("led pin" support for Symbios compatible cards can remain
1501enabled when using Tekram cards. It does nothing useful for Tekram host
1502adaptors but does not cause problems either.)
1503
1504
150517.2 Symbios NVRAM layout
1506
1507typical data at NVRAM address 0x100 (53c810a NVRAM)
1508-----------------------------------------------------------
150900 00
151064 01
15118e 0b
1512
151300 30 00 00 00 00 07 00 00 00 00 00 00 00 07 04 10 04 00 00
1514
151504 00 0f 00 00 10 00 50 00 00 01 00 00 62
151604 00 03 00 00 10 00 58 00 00 01 00 00 63
151704 00 01 00 00 10 00 48 00 00 01 00 00 61
151800 00 00 00 00 00 00 00 00 00 00 00 00 00
1519
15200f 00 08 08 64 00 0a 00
15210f 00 08 08 64 00 0a 00
15220f 00 08 08 64 00 0a 00
15230f 00 08 08 64 00 0a 00
15240f 00 08 08 64 00 0a 00
15250f 00 08 08 64 00 0a 00
15260f 00 08 08 64 00 0a 00
15270f 00 08 08 64 00 0a 00
1528
15290f 00 08 08 64 00 0a 00
15300f 00 08 08 64 00 0a 00
15310f 00 08 08 64 00 0a 00
15320f 00 08 08 64 00 0a 00
15330f 00 08 08 64 00 0a 00
15340f 00 08 08 64 00 0a 00
15350f 00 08 08 64 00 0a 00
15360f 00 08 08 64 00 0a 00
1537
153800 00 00 00 00 00 00 00
153900 00 00 00 00 00 00 00
154000 00 00 00 00 00 00 00
154100 00 00 00 00 00 00 00
154200 00 00 00 00 00 00 00
154300 00 00 00 00 00 00 00
154400 00 00 00 00 00 00 00
154500 00 00 00 00 00 00 00
1546
154700 00 00 00 00 00 00 00
154800 00 00 00 00 00 00 00
154900 00 00 00 00 00 00 00
155000 00 00 00 00 00 00 00
155100 00 00 00 00 00 00 00
155200 00 00 00 00 00 00 00
155300 00 00 00 00 00 00 00
155400 00 00 00 00 00 00 00
1555
155600 00 00 00 00 00 00 00
155700 00 00 00 00 00 00 00
155800 00 00 00 00 00 00 00
1559
1560fe fe
156100 00
156200 00
1563-----------------------------------------------------------
1564NVRAM layout details
1565
1566NVRAM Address 0x000-0x0ff not used
1567              0x100-0x26f initialised data
1568              0x270-0x7ff not used
1569
1570general layout
1571
1572        header - 6 bytes,
1573        data - 356 bytes (checksum is byte sum of this data)
1574        trailer - 6 bytes
1575                  ---
1576        total 368 bytes
1577
1578data area layout
1579
1580        controller set up - 20 bytes
1581        boot configuration - 56 bytes (4x14 bytes)
1582        device set up - 128 bytes (16x8 bytes)
1583        unused (spare?) - 152 bytes (19x8 bytes)
1584                             ---
1585        total 356 bytes
1586
1587-----------------------------------------------------------
1588header
1589
159000 00 - ?? start marker
159164 01 - byte count (lsb/msb excludes header/trailer)
15928e 0b - checksum (lsb/msb excludes header/trailer)
1593-----------------------------------------------------------
1594controller set up
1595
159600 30 00 00 00 00 07 00 00 00 00 00 00 00 07 04 10 04 00 00
1597                   | | | |
1598                   | | | -- host ID
1599                   | | |
1600                   | | --Removable Media Support
1601                   | | 0x00 = none
1602                   | | 0x01 = Bootable Device
1603                   | | 0x02 = All with Media
1604                   | |
1605                   | --flag bits 2
1606                   | 0x00000001= scan order hi->low
1607                   | (default 0x00 - scan low->hi)
1608                    --flag bits 1
1609                       0x00000001 scam enable
1610                       0x00000010 parity enable
1611                       0x00000100 verbose boot msgs
1612
1613remaining bytes unknown - they do not appear to change in my
1614current set up for any of the controllers.
1615
1616default set up is identical for 53c810a and 53c875 NVRAM
1617(Removable Media added Symbios BIOS version 4.09)
1618-----------------------------------------------------------
1619boot configuration
1620
1621boot order set by order of the devices in this table
1622
162304 00 0f 00 00 10 00 50 00 00 01 00 00 62 -- 1st controller
162404 00 03 00 00 10 00 58 00 00 01 00 00 63 2nd controller
162504 00 01 00 00 10 00 48 00 00 01 00 00 61 3rd controller
162600 00 00 00 00 00 00 00 00 00 00 00 00 00 4th controller
1627       | | | | | | | |
1628       | | | | | | ---- PCI io port adr
1629       | | | | | --0x01 init/scan at boot time
1630       | | | | --PCI device/function number (0xdddddfff)
1631       | | ----- ?? PCI vendor ID (lsb/msb)
1632        ----PCI device ID (lsb/msb)
1633
1634?? use of this data is a guess but seems reasonable
1635
1636remaining bytes unknown - they do not appear to change in my
1637current set up
1638
1639default set up is identical for 53c810a and 53c875 NVRAM
1640-----------------------------------------------------------
1641device set up (up to 16 devices - includes controller)
1642
16430f 00 08 08 64 00 0a 00 - id 0
16440f 00 08 08 64 00 0a 00
16450f 00 08 08 64 00 0a 00
16460f 00 08 08 64 00 0a 00
16470f 00 08 08 64 00 0a 00
16480f 00 08 08 64 00 0a 00
16490f 00 08 08 64 00 0a 00
16500f 00 08 08 64 00 0a 00
1651
16520f 00 08 08 64 00 0a 00
16530f 00 08 08 64 00 0a 00
16540f 00 08 08 64 00 0a 00
16550f 00 08 08 64 00 0a 00
16560f 00 08 08 64 00 0a 00
16570f 00 08 08 64 00 0a 00
16580f 00 08 08 64 00 0a 00
16590f 00 08 08 64 00 0a 00 - id 15
1660 | | | | | |
1661 | | | | ----timeout (lsb/msb)
1662 | | | --synch period (0x?? 40 Mtrans/sec- fast 40) (probably 0x28)
1663 | | | (0x30 20 Mtrans/sec- fast 20)
1664 | | | (0x64 10 Mtrans/sec- fast )
1665 | | | (0xc8 5 Mtrans/sec)
1666 | | | (0x00 asynchronous)
1667 | | -- ?? max sync offset (0x08 in NVRAM on 53c810a)
1668 | | (0x10 in NVRAM on 53c875)
1669 | --device bus width (0x08 narrow)
1670 | (0x10 16 bit wide)
1671  --flag bits
1672    0x00000001 - disconnect enabled
1673    0x00000010 - scan at boot time
1674    0x00000100 - scan luns
1675    0x00001000 - queue tags enabled
1676
1677remaining bytes unknown - they do not appear to change in my
1678current set up
1679
1680?? use of this data is a guess but seems reasonable
1681(but it could be max bus width)
1682
1683default set up for 53c810a NVRAM
1684default set up for 53c875 NVRAM - bus width - 0x10
1685                                - sync offset ? - 0x10
1686                                - sync period - 0x30
1687-----------------------------------------------------------
1688?? spare device space (32 bit bus ??)
1689
169000 00 00 00 00 00 00 00 (19x8bytes)
1691.
1692.
169300 00 00 00 00 00 00 00
1694
1695default set up is identical for 53c810a and 53c875 NVRAM
1696-----------------------------------------------------------
1697trailer
1698
1699fe fe - ? end marker ?
170000 00
170100 00
1702
1703default set up is identical for 53c810a and 53c875 NVRAM
1704-----------------------------------------------------------
1705
1706
1707
170817.3 Tekram NVRAM layout
1709
1710nvram 64x16 (1024 bit)
1711
1712Drive settings
1713
1714Drive ID 0-15 (addr 0x0yyyy0 = device setup, yyyy = ID)
1715              (addr 0x0yyyy1 = 0x0000)
1716
1717    x x x x x x x x x x x x x x x x
1718               | | | | | | | | |
1719               | | | | | | | | ----- parity check 0 - off
1720               | | | | | | | | 1 - on
1721               | | | | | | | |
1722               | | | | | | | ------- sync neg 0 - off
1723               | | | | | | | 1 - on
1724               | | | | | | |
1725               | | | | | | --------- disconnect 0 - off
1726               | | | | | | 1 - on
1727               | | | | | |
1728               | | | | | ----------- start cmd 0 - off
1729               | | | | | 1 - on
1730               | | | | |
1731               | | | | -------------- tagged cmds 0 - off
1732               | | | | 1 - on
1733               | | | |
1734               | | | ---------------- wide neg 0 - off
1735               | | | 1 - on
1736               | | |
1737                --------------------------- sync rate 0 - 10.0 Mtrans/sec
1738                                                           1 - 8.0
1739                                                           2 - 6.6
1740                                                           3 - 5.7
1741                                                           4 - 5.0
1742                                                           5 - 4.0
1743                                                           6 - 3.0
1744                                                           7 - 2.0
1745                                                           7 - 2.0
1746                                                           8 - 20.0
1747                                                           9 - 16.7
1748                                                           a - 13.9
1749                                                           b - 11.9
1750
1751Global settings
1752
1753Host flags 0 (addr 0x100000, 32)
1754
1755    x x x x x x x x x x x x x x x x
1756    | | | | | | | | | | | |
1757    | | | | | | | | ----------- host ID 0x00 - 0x0f
1758    | | | | | | | |
1759    | | | | | | | ----------------------- support for 0 - off
1760    | | | | | | | > 2 drives 1 - on
1761    | | | | | | |
1762    | | | | | | ------------------------- support drives 0 - off
1763    | | | | | | > 1Gbytes 1 - on
1764    | | | | | |
1765    | | | | | --------------------------- bus reset on 0 - off
1766    | | | | | power on 1 - on
1767    | | | | |
1768    | | | | ----------------------------- active neg 0 - off
1769    | | | | 1 - on
1770    | | | |
1771    | | | -------------------------------- imm seek 0 - off
1772    | | | 1 - on
1773    | | |
1774    | | ---------------------------------- scan luns 0 - off
1775    | | 1 - on
1776    | |
1777     -------------------------------------- removable 0 - disable
1778                                            as BIOS dev 1 - boot device
1779                                                           2 - all
1780
1781Host flags 1 (addr 0x100001, 33)
1782
1783    x x x x x x x x x x x x x x x x
1784               | | | | | |
1785               | | | --------- boot delay 0 - 3 sec
1786               | | | 1 - 5
1787               | | | 2 - 10
1788               | | | 3 - 20
1789               | | | 4 - 30
1790               | | | 5 - 60
1791               | | | 6 - 120
1792               | | |
1793                --------------------------- max tag cmds 0 - 2
1794                                                           1 - 4
1795                                                           2 - 8
1796                                                           3 - 16
1797                                                           4 - 32
1798
1799Host flags 2 (addr 0x100010, 34)
1800
1801    x x x x x x x x x x x x x x x x
1802                                     |
1803                                      ----- F2/F6 enable 0 - off ???
1804                                                           1 - on ???
1805
1806checksum (addr 0x111111)
1807
1808checksum = 0x1234 - (sum addr 0-63)
1809
1810----------------------------------------------------------------------------
1811
1812default nvram data:
1813
18140x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
18150x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
18160x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
18170x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
1818
18190x0f07 0x0400 0x0001 0x0000 0x0000 0x0000 0x0000 0x0000
18200x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000
18210x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000
18220x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0xfbbc
1823
1824
182518. Support for Big Endian
1826
1827The PCI local bus has been primarily designed for x86 architecture.
1828As a consequence, PCI devices generally expect DWORDS using little endian
1829byte ordering.
1830
183118.1 Big Endian CPU
1832
1833In order to support NCR chips on a Big Endian architecture the driver has to
1834perform byte reordering each time it is needed. This feature has been
1835added to the driver by Cort <cort@cs.nmt.edu> and is available in driver
1836version 2.5 and later ones. For the moment Big Endian support has only
1837been tested on Linux/PPC (PowerPC).
1838
183918.2 NCR chip in Big Endian mode of operations
1840
1841It can be read in SYMBIOS documentation that some chips support a special
1842Big Endian mode, on paper: 53C815, 53C825A, 53C875, 53C875N, 53C895.
1843This mode of operations is not software-selectable, but needs pin named
1844BigLit to be pulled-up. Using this mode, most of byte reorderings should
1845be avoided when the driver is running on a Big Endian CPU.
1846Driver version 2.5 is also, in theory, ready for this feature.
1847
1848===============================================================================
1849End of NCR53C8XX driver README file
1850

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