1 The Linux NCR53C8XX/SYM53C8XX drivers README file
3 Written by Gerard Roudier <groudier@free.fr>
5 95170 DEUIL LA BARRE - FRANCE
8 ===============================================================================
11 2. Supported chips and SCSI features
12 3. 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)
15 4. Memory mapped I/O versus normal I/O
16 5. Tagged command queueing
18 7. Profiling information
20 8.1 Set minimum synchronous period
22 8.3 Set maximum number of concurrent tagged commands
23 8.4 Set order type for tagged command
25 8.6 Clear profile counters
26 8.7 Set flag (no_disc)
28 8.9 Reset all logical units of a target
29 8.10 Abort all tasks of all logical units of a target
30 9. Configuration parameters
31 10. Boot setup commands
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
47 10.2.14 Differential mode
50 10.2.17 Fix up PCI configuration space
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
61 11. Some constants and flags of the ncr53c8xx.h header file
63 13. Architecture dependent features
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
70 15. SCSI problem troubleshooting
72 15.2 Understanding hardware error reports
73 16. 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
76 17. Serial NVRAM support (by Richard Waltham)
78 17.2 Symbios NVRAM layout
79 17.3 Tekram NVRAM layout
80 18. Support for Big Endian
82 18.2 NCR chip in Big Endian mode of operations
84 ===============================================================================
88 The initial Linux ncr53c8xx driver has been a port of the ncr driver from
89 FreeBSD that has been achieved in November 1995 by:
90 Gerard Roudier <groudier@free.fr>
92 The original driver has been written for 386bsd and FreeBSD by:
93 Wolfgang Stanglmeier <wolf@cologne.de>
94 Stefan Esser <se@mi.Uni-Koeln.de>
96 It is now available as a bundle of 2 drivers:
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
106 You can find technical information about the NCR 8xx family in the
107 PCI-HOWTO written by Michael Will and in the SCSI-HOWTO written by
110 Information about new chips is available at LSILOGIC web server:
112 http://www.lsilogic.com/
114 SCSI standard documentations are available at SYMBIOS ftp server:
116 ftp://ftp.symbios.com/
118 Useful SCSI tools written by Eric Youngdale are available at tsx-11:
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
123 These tools are not ALPHA but quite clean and work quite well.
124 It is essential you have the 'scsiinfo' package.
126 This short documentation describes the features of the generic and enhanced
127 drivers, configuration parameters and control commands available through
128 the proc SCSI file system read / write operations.
130 This driver has been tested OK with linux/i386, Linux/Alpha and Linux/PPC.
132 Latest driver version and patches are available at:
134 ftp://ftp.tux.org/pub/people/gerard-roudier
136 ftp://ftp.symbios.com/mirror/ftp.tux.org/pub/tux/roudier/drivers
138 I am not a native speaker of English and there are probably lots of
139 mistakes in this README file. Any help will be welcome.
142 2. Supported chips and SCSI features
144 The following features are supported for all chips:
146 Synchronous negotiation
148 Tagged command queuing
150 Master parity checking
152 "Wide negotiation" is supported for chips that allow it. The
153 following table shows some characteristics of NCR 8xx family chips
154 and what drivers support them.
156 Supported by Supported by
157 On board the generic the enhanced
158 Chip SDMS BIOS Wide SCSI std. Max. sync driver driver
159 ---- --------- ---- --------- ---------- ------------ -------------
160 810 N N FAST10 10 MB/s Y N
161 810A N N FAST10 10 MB/s Y Y
162 815 Y N FAST10 10 MB/s Y N
163 825 Y Y FAST10 20 MB/s Y N
164 825A Y Y FAST10 20 MB/s Y Y
165 860 N N FAST20 20 MB/s Y Y
166 875 Y Y FAST20 40 MB/s Y Y
167 876 Y Y FAST20 40 MB/s Y Y
168 895 Y Y FAST40 80 MB/s Y Y
169 895A Y Y FAST40 80 MB/s Y Y
170 896 Y Y FAST40 80 MB/s Y Y
171 897 Y Y FAST40 80 MB/s Y Y
172 1510D Y Y FAST40 80 MB/s Y Y
173 1010 Y Y FAST80 160 MB/s N Y
174 1010_66* Y Y FAST80 160 MB/s N Y
176 * Chip supports 33MHz and 66MHz PCI buses.
179 Summary of other supported features:
181 Module: allow to load the driver
182 Memory mapped I/O: increases performance
183 Profiling information: read operations from the proc SCSI file system
184 Control commands: write operations to the proc SCSI file system
185 Debugging information: written to syslog (expert only)
189 Serial NVRAM: Symbios and Tekram formats
192 3. Advantages of the enhanced 896 driver
194 3.1 Optimized SCSI SCRIPTS.
196 The 810A, 825A, 875, 895, 896 and 895A support new SCSI SCRIPTS instructions
197 named LOAD and STORE that allow to move up to 1 DWORD from/to an IO register
198 to/from memory much faster that the MOVE MEMORY instruction that is supported
199 by the 53c7xx and 53c8xx family.
200 The LOAD/STORE instructions support absolute and DSA relative addressing
201 modes. The SCSI SCRIPTS had been entirely rewritten using LOAD/STORE instead
202 of MOVE MEMORY instructions.
204 3.2 New features of the SYM53C896 (64 bit PCI dual LVD SCSI controller)
206 The 896 and the 895A allows handling of the phase mismatch context from
207 SCRIPTS (avoids the phase mismatch interrupt that stops the SCSI processor
208 until the C code has saved the context of the transfer).
209 Implementing this without using LOAD/STORE instructions would be painful
210 and I didn't even want to try it.
212 The 896 chip supports 64 bit PCI transactions and addressing, while the
213 895A supports 32 bit PCI transactions and 64 bit addressing.
214 The SCRIPTS processor of these chips is not true 64 bit, but uses segment
215 registers for bit 32-63. Another interesting feature is that LOAD/STORE
216 instructions that address the on-chip RAM (8k) remain internal to the chip.
218 Due to the use of LOAD/STORE SCRIPTS instructions, this driver does not
219 support the following chips:
220 - SYM53C810 revision < 0x10 (16)
221 - SYM53C815 all revisions
222 - SYM53C825 revision < 0x10 (16)
224 4. Memory mapped I/O versus normal I/O
226 Memory mapped I/O has less latency than normal I/O. Since
227 linux-1.3.x, memory mapped I/O is used rather than normal I/O. Memory
228 mapped I/O seems to work fine on most hardware configurations, but
229 some poorly designed motherboards may break this feature.
231 The configuration option CONFIG_SCSI_NCR53C8XX_IOMAPPED forces the
232 driver to use normal I/O in all cases.
235 5. Tagged command queueing
237 Queuing more than 1 command at a time to a device allows it to perform
238 optimizations based on actual head positions and its mechanical
239 characteristics. This feature may also reduce average command latency.
240 In order to really gain advantage of this feature, devices must have
241 a reasonable cache size (No miracle is to be expected for a low-end
242 hard disk with 128 KB or less).
243 Some known SCSI devices do not properly support tagged command queuing.
244 Generally, firmware revisions that fix this kind of problems are available
245 at respective vendor web/ftp sites.
246 All I can say is that the hard disks I use on my machines behave well with
247 this driver with tagged command queuing enabled:
254 If your controller has NVRAM, you can configure this feature per target
255 from the user setup tool. The Tekram Setup program allows to tune the
256 maximum number of queued commands up to 32. The Symbios Setup only allows
257 to enable or disable this feature.
259 The maximum number of simultaneous tagged commands queued to a device
260 is currently set to 8 by default. This value is suitable for most SCSI
261 disks. With large SCSI disks (>= 2GB, cache >= 512KB, average seek time
262 <= 10 ms), using a larger value may give better performances.
264 The sym53c8xx driver supports up to 255 commands per device, and the
265 generic ncr53c8xx driver supports up to 64, but using more than 32 is
266 generally not worth-while, unless you are using a very large disk or disk
267 array. It is noticeable that most of recent hard disks seem not to accept
268 more than 64 simultaneous commands. So, using more than 64 queued commands
269 is probably just resource wasting.
271 If your controller does not have NVRAM or if it is managed by the SDMS
272 BIOS/SETUP, you can configure tagged queueing feature and device queue
273 depths from the boot command-line. For example:
275 ncr53c8xx=tags:4/t2t3q15-t4q7/t1u0q32
277 will set tagged commands queue depths as follow:
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
285 In some special conditions, some SCSI disk firmwares may return a
286 QUEUE FULL status for a SCSI command. This behaviour is managed by the
287 driver using the following heuristic:
289 - Each time a QUEUE FULL status is returned, tagged queue depth is reduced
290 to the actual number of disconnected commands.
292 - Every 1000 successfully completed SCSI commands, if allowed by the
293 current limit, the maximum number of queueable commands is incremented.
295 Since QUEUE FULL status reception and handling is resource wasting, the
296 driver notifies by default this problem to user by indicating the actual
297 number of commands used and their status, as well as its decision on the
298 device queue depth change.
299 The heuristic used by the driver in handling QUEUE FULL ensures that the
300 impact on performances is not too bad. You can get rid of the messages by
301 setting verbose level to zero, as follow:
303 1st method: boot your system using 'ncr53c8xx=verb:0' option.
304 2nd method: apply "setverbose 0" control command to the proc fs entry
305 corresponding to your controller after boot-up.
309 The driver supports SCSI parity checking and PCI bus master parity
310 checking. These features must be enabled in order to ensure safe data
311 transfers. However, some flawed devices or mother boards will have
312 problems with parity. You can disable either PCI parity or SCSI parity
313 checking by entering appropriate options from the boot command line.
314 (See 10: Boot setup commands).
316 7. Profiling information
318 Profiling information is available through the proc SCSI file system.
319 Since gathering profiling information may impact performances, this
320 feature is disabled by default and requires a compilation configuration
321 option to be set to Y.
323 The device associated with a host has the following pathname:
325 /proc/scsi/ncr53c8xx/N (N=0,1,2 ....)
327 Generally, only 1 board is used on hardware configuration, and that device is:
328 /proc/scsi/ncr53c8xx/0
330 However, if the driver has been made as module, the number of the
331 hosts is incremented each time the driver is loaded.
333 In order to display profiling information, just enter:
335 cat /proc/scsi/ncr53c8xx/0
337 and you will get something like the following text:
339 -------------------------------------------------------
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
345 Profiling information:
356 -------------------------------------------------------
358 General information is easy to understand. The device ID and the
359 revision ID identify the SCSI chip as follows:
361 Chip Device id Revision Id
362 ---- --------- -----------
372 The profiling information is updated upon completion of SCSI commands.
373 A data structure is allocated and zeroed when the host adapter is
374 attached. So, if the driver is a module, the profile counters are
375 cleared each time the driver is loaded. The "clearprof" command
376 allows you to clear these counters at any time.
378 The following counters are available:
380 ("num" prefix means "number of",
381 "ms" means milli-seconds)
384 Number of completed commands
385 Example above: 18014 completed commands
388 Number of kbytes transferred
389 Example above: 671 MB transferred
392 Number of SCSI disconnections
393 Example above: 25763 SCSI disconnections
396 number of script interruptions (phase mismatch)
397 Example above: 1673 script interruptions
400 Number of interrupts other than "on the fly"
401 Example above: 1685 interruptions not "on the fly"
404 Number of interrupts "on the fly"
405 Example above: 18038 interruptions "on the fly"
408 Elapsed time for SCSI commands setups
409 Example above: 4.94 seconds
412 Elapsed time for data transfers
413 Example above: 369.94 seconds spent for data transfer
416 Elapsed time for SCSI disconnections
417 Example above: 183.09 seconds spent disconnected
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
424 Due to the 1/100 second tick of the system clock, "ms_post" time may
427 In the example above, we got 18038 interrupts "on the fly" and only
428 1673 script breaks generally due to disconnections inside a segment
434 Control commands can be sent to the driver with write operations to
435 the proc SCSI file system. The generic command syntax is the
438 echo "<verb> <parameters>" >/proc/scsi/ncr53c8xx/0
439 (assumes controller number is 0)
441 Using "all" for "<target>" parameter with the commands below will
442 apply to all targets of the SCSI chain (except the controller).
446 8.1 Set minimum synchronous period factor
448 setsync <target> <period factor>
450 target: target number
451 period: minimum synchronous period.
452 Maximum speed = 1000/(4*period factor) except for special
455 Specify a period of 255, to force asynchronous transfer mode.
457 10 means 25 nano-seconds synchronous period
458 11 means 30 nano-seconds synchronous period
459 12 means 50 nano-seconds synchronous period
463 setwide <target> <size>
465 target: target number
466 size: 0=8 bits, 1=16bits
468 8.3 Set maximum number of concurrent tagged commands
470 settags <target> <tags>
472 target: target number
473 tags: number of concurrent tagged commands
474 must not be greater than SCSI_NCR_MAX_TAGS (default: 8)
476 8.4 Set order type for tagged command
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
490 setdebug <list of debug flags>
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
503 Use "setdebug" with no argument to reset debug flags.
506 8.6 Clear profile counters
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.
515 8.7 Set flag (no_disc)
517 setflag <target> <flag>
519 target: target number
521 For the moment, only one flag is available:
523 no_disc: not allow target to disconnect.
525 Do not specify any flag in order to reset the flag. For example:
527 will reset no_disc flag for target 4, so will allow it disconnections.
529 will allow disconnection for all devices on the SCSI bus.
532 8.8 Set verbose level
536 The driver default verbose level is 1. This command allows to change
537 th driver verbose level after boot-up.
539 8.9 Reset all logical units of a target
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)
547 8.10 Abort all tasks of all logical units of a target
551 target: target number
552 The driver will try to send a ABORT message to all the logical units
554 (Only supported by the SYM53C8XX driver and provided for test purpose)
557 9. Configuration parameters
559 If the firmware of all your devices is perfect enough, all the
560 features supported by the driver can be enabled at start-up. However,
561 if only one has a flaw for some SCSI feature, you can disable the
562 support by the driver of this feature at linux start-up and enable
563 this feature after boot-up only for devices that support it safely.
565 CONFIG_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
572 CONFIG_SCSI_NCR53C8XX_DEFAULT_TAGS (default answer: 8)
573 Default tagged command queue depth.
575 CONFIG_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.
579 CONFIG_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".
585 CONFIG_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).
590 CONFIG_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.
595 CONFIG_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.
607 CONFIG_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).
620 10. Boot setup commands
624 Setup commands can be passed to the driver either at boot time or as a
625 string variable using 'insmod'.
627 A boot setup command for the ncr53c8xx (sym53c8xx) driver begins with the
628 driver name "ncr53c8xx="(sym53c8xx). The kernel syntax parser then expects
629 an optional list of integers separated with comma followed by an optional
630 list of comma-separated strings. Example of boot setup command under lilo
633 lilo: linux root=/dev/hda2 ncr53c8xx=tags:4,sync:10,debug:0x200
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.
639 Since comma seems not to be allowed when defining a string variable using
640 'insmod', the driver also accepts <space> as option separator.
641 The following command will install driver module with the same options as
644 insmod ncr53c8xx.o ncr53c8xx="tags:4 sync:10 debug:0x200"
646 For the moment, the integer list of arguments is discarded by the driver.
647 It will be used in the future in order to allow a per controller setup.
649 Each string argument must be specified as "keyword:value". Only lower-case
650 characters and digits are allowed.
652 In a system that contains multiple 53C8xx adapters insmod will install the
653 specified driver on each adapter. To exclude a chip use the 'excl' keyword.
655 The sequence of commands,
657 insmod sym53c8xx sym53c8xx=excl:0x1400
660 installs the sym53c8xx driver on all adapters except the one at IO port
661 address 0x1400 and then installs the ncr53c8xx driver to the adapter at IO
665 10.2 Available arguments
667 10.2.1 Master parity checking
671 10.2.2 Scsi parity checking
675 10.2.3 Scsi disconnections
679 10.2.4 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
689 10.2.5 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
697 10.2.6 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.
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.
711 10.2.7 Default synchronous period factor
712 sync:255 disabled (asynchronous transfer mode)
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
719 In all cases, the driver will use the minimum transfer period supported by
720 controllers according to NCR53C8XX chip type.
722 10.2.8 Negotiate synchronous with all devices
727 10.2.9 Verbosity level
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:
750 You can play safely with DEBUG_NEGO. However, some of these flags may
751 generate bunches of syslog messages.
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
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')
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.
778 10.2.14 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
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
791 (Bits 0x10 and 0x20 can be combined with hardware irq mode option)
793 10.2.16 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.
798 10.2.17 Fix up PCI configuration space
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.
807 Use 'pcifix:7' in order to allow the driver to fix up all PCI features.
810 nvram:n do not look for serial NVRAM
811 nvram:y test controllers for onboard serial NVRAM
812 (alternate binary form)
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)
820 10.2.19 Check SCSI BUS
823 Available option bits:
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.
829 10.2.20 Exclude a host from being attached
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.
836 10.2.21 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.
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.
846 10.2.22 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:
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.
857 safe:y load the following assumed fail safe initial setup
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
881 10.3 Advised boot setup commands
883 If the driver has been configured with default options, the equivalent
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
889 For an installation diskette or a safe but not fast system,
892 ncr53c8xx=safe:y,mpar:y,disc:y
893 ncr53c8xx=safe:y,disc:y
894 ncr53c8xx=safe:y,mpar:y
897 My personal system works flawlessly with the following equivalent setup:
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
902 The 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"
904 to your boot setup command in order to check the actual setup the driver is
907 10.4 PCI configuration fix-up boot option
911 Available option bits:
912 0x1: Set PCI cache-line size register if not set.
913 0x2: Set write and invalidate bit in PCI command register.
915 Use 'pcifix:3' in order to allow the driver to fix both PCI features.
917 These options only apply to new SYMBIOS chips 810A, 825A, 860, 875
918 and 895 and are only supported for Pentium and 486 class processors.
919 Recent SYMBIOS 53C8XX scsi processors are able to use PCI read multiple
920 and PCI write and invalidate commands. These features require the
921 cache line size register to be properly set in the PCI configuration
922 space of the chips. On the other hand, chips will use PCI write and
923 invalidate commands only if the corresponding bit is set to 1 in the
924 PCI command register.
926 Not all PCI bioses set the PCI cache line register and the PCI write and
927 invalidate bit in the PCI configuration space of 53C8XX chips.
928 Optimized PCI accesses may be broken for some PCI/memory controllers or
929 make problems with some PCI boards.
931 This fix-up worked flawlessly on my previous system.
932 (MB Triton HX / 53C875 / 53C810A)
933 I use these options at my own risks as you will do if you decide to
937 10.5 Serial NVRAM support boot option
939 nvram:n do not look for serial NVRAM
940 nvram:y test controllers for onboard serial NVRAM
942 This option can also been entered as an hexadecimal value that allows
943 to control what information the driver will get from the NVRAM and what
944 information it will ignore.
945 For details see '17. Serial NVRAM support'.
947 When this option is enabled, the driver tries to detect all boards using
948 a Serial NVRAM. This memory is used to hold user set up parameters.
950 The parameters the driver is able to get from the NVRAM depend on the
951 data format used, as follow:
953 Tekram format Symbios format
954 General and host parameters
957 SCSI parity checking Y Y
958 Verbose boot messages N Y
959 SCSI devices parameters
960 Synchronous transfer speed Y Y
962 Tagged Command Queuing enabled Y Y
963 Disconnections enabled Y Y
964 Scan at boot time N Y
966 In order to speed up the system boot, for each device configured without
967 the "scan at boot time" option, the driver forces an error on the
968 first TEST UNIT READY command received for this device.
970 Some SDMS BIOS revisions seem to be unable to boot cleanly with very fast
971 hard disks. In such a situation you cannot configure the NVRAM with
972 optimized parameters value.
974 The 'nvram' boot option can be entered in hexadecimal form in order
975 to ignore some options configured in the NVRAM, as follow:
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)
984 Option 0x80 is only supported by the sym53c8xx driver and is disabled by
985 default. Result is that, by default (option not set), the sym53c8xx driver
986 will not attach controllers set to OFF in the NVRAM.
988 The ncr53c8xx always tries to attach all the controllers. Option 0x80 has
989 not been added to the ncr53c8xx driver, since it has been reported to
990 confuse users who use this driver since a long time. If you desire a
991 controller not to be attached by the ncr53c8xx driver at Linux boot, you
992 must use the 'excl' driver boot option.
994 10.6 SCSI BUS checking boot option.
996 When this option is set to a non-zero value, the driver checks SCSI lines
997 logic state, 100 micro-seconds after having asserted the SCSI RESET line.
998 The driver just reads SCSI lines and checks all lines read FALSE except RESET.
999 Since SCSI devices shall release the BUS at most 800 nano-seconds after SCSI
1000 RESET has been asserted, any signal to TRUE may indicate a SCSI BUS problem.
1001 Unfortunately, the following common SCSI BUS problems are not detected:
1002 - Only 1 terminator installed.
1003 - Misplaced terminators.
1004 - Bad quality terminators.
1005 On the other hand, either bad cabling, broken devices, not conformant
1006 devices, ... may cause a SCSI signal to be wrong when te driver reads it.
1008 10.7 IMMEDIATE ARBITRATION boot option
1010 This option is only supported by the SYM53C8XX driver (not by the NCR53C8XX).
1012 SYMBIOS 53C8XX chips are able to arbitrate for the SCSI BUS as soon as they
1013 have detected an expected disconnection (BUS FREE PHASE). For this process
1014 to be started, bit 1 of SCNTL1 IO register must be set when the chip is
1015 connected to the SCSI BUS.
1017 When this feature has been enabled for the current connection, the chip has
1018 every chance to win arbitration if only devices with lower priority are
1019 competing for the SCSI BUS. By the way, when the chip is using SCSI id 7,
1020 then it will for sure win the next SCSI BUS arbitration.
1022 Since, there is no way to know what devices are trying to arbitrate for the
1023 BUS, using this feature can be extremely unfair. So, you are not advised
1024 to enable it, or at most enable this feature for the case the chip lost
1025 the previous arbitration (boot option 'iarb:1').
1027 This feature has the following advantages:
1029 a) Allow the initiator with ID 7 to win arbitration when it wants so.
1030 b) 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.
1034 Hmmm... But (a) may just prevent other devices from reselecting the initiator,
1035 and delay data transfers or status/completions, and (b) may just waste
1036 SCSI BUS bandwidth if the SCRIPTS execution lasts more than 4 micro-seconds.
1038 The use of IARB needs the SCSI_NCR_IARB_SUPPORT option to have been defined
1039 at compile time and the 'iarb' boot option to have been set to a non zero
1040 value at boot time. It is not that useful for real work, but can be used
1041 to stress SCSI devices or for some applications that can gain advantage of
1042 it. By the way, if you experience badnesses like 'unexpected disconnections',
1043 'bad reselections', etc... when using IARB on heavy IO load, you should not
1044 be surprised, because force-feeding anything and blocking its arse at the
1045 same time cannot work for a long time. :-))
1048 11. Some constants and flags of the ncr53c8xx.h header file
1050 Some of these are defined from the configuration parameters. To
1051 change other "defines", you must edit the header file. Do that only
1052 if you know what you are doing.
1054 SCSI_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:
1065 SCSI_NCR_IOMAPPED (default: not defined)
1066 If defined, normal I/O is forced.
1068 SCSI_NCR_SHARE_IRQ (default: defined)
1069 If defined, request shared IRQ.
1071 SCSI_NCR_MAX_TAGS (default: 8)
1072 Maximum number of simultaneous tagged commands to a device.
1073 Can be changed by "settags <target> <maxtags>"
1075 SCSI_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>"
1080 SCSI_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.
1084 SCSI_NCR_ALWAYS_SIMPLE_TAG (default: defined)
1085 Use SIMPLE TAG for read and write commands.
1086 Can be changed by "setorder <ordered|simple|default>"
1088 SCSI_NCR_SETUP_DISCONNECTION (default: defined)
1089 If defined, targets are allowed to disconnect.
1091 SCSI_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>"
1095 SCSI_NCR_SETUP_MASTER_PARITY (default: defined)
1096 If defined, master parity checking is enabled.
1098 SCSI_NCR_SETUP_MASTER_PARITY (default: defined)
1099 If defined, SCSI parity checking is enabled.
1101 SCSI_NCR_PROFILE_SUPPORT (default: not defined)
1102 If defined, profiling information is gathered.
1104 SCSI_NCR_MAX_SCATTER (default: 128)
1105 Scatter list size of the driver ccb.
1107 SCSI_NCR_MAX_TARGET (default: 16)
1108 Max number of targets per host.
1110 SCSI_NCR_MAX_HOST (default: 2)
1111 Max number of host controllers.
1113 SCSI_NCR_SETTLE_TIME (default: 2)
1114 Number of seconds the driver will wait after reset.
1116 SCSI_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.
1121 SCSI_NCR_CAN_QUEUE (default: 7*SCSI_NCR_MAX_TAGS)
1122 Max number of commands that can be queued to a host.
1124 SCSI_NCR_CMD_PER_LUN (default: SCSI_NCR_MAX_TAGS)
1125 Max number of commands queued to a host for a device.
1127 SCSI_NCR_SG_TABLESIZE (default: SCSI_NCR_MAX_SCATTER-1)
1128 Max size of the Linux scatter/gather list.
1130 SCSI_NCR_MAX_LUN (default: 8)
1131 Max number of LUNs per target.
1136 This driver is part of the linux kernel distribution.
1137 Driver files are located in the sub-directory "drivers/scsi" of the
1142 README.ncr53c8xx : this file
1143 ChangeLog.ncr53c8xx : change log
1144 ncr53c8xx.h : definitions
1145 ncr53c8xx.c : the driver code
1147 New driver versions are made available separately in order to allow testing
1148 changes and new features prior to including them into the linux kernel
1149 distribution. The following URL provides information on latest available
1152 ftp://ftp.tux.org/pub/people/gerard-roudier/README
1155 13. Architecture dependent features.
1162 14.1 Tagged commands with Iomega Jaz device
1164 I have not tried this device, however it has been reported to me the
1165 following: This device is capable of Tagged command queuing. However
1166 while spinning up, it rejects Tagged commands. This behaviour is
1167 conforms to 6.8.2 of SCSI-2 specifications. The current behaviour of
1168 the driver in that situation is not satisfying. So do not enable
1169 Tagged command queuing for devices that are able to spin down. The
1170 other problem that may appear is timeouts. The only way to avoid
1171 timeouts seems to edit linux/drivers/scsi/sd.c and to increase the
1172 current timeout values.
1174 14.2 Device names change when another controller is added.
1176 When you add a new NCR53C8XX chip based controller to a system that already
1177 has one or more controllers of this family, it may happen that the order
1178 the driver registers them to the kernel causes problems due to device
1180 When at least one controller uses NvRAM, SDMS BIOS version 4 allows you to
1181 define the order the BIOS will scan the scsi boards. The driver attaches
1182 controllers according to BIOS information if NvRAM detect option is set.
1184 If your controllers do not have NvRAM, you can:
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.
1191 14.3 Using only 8 bit devices with a WIDE SCSI controller.
1193 When only 8 bit NARROW devices are connected to a 16 bit WIDE SCSI controller,
1194 you must ensure that lines of the wide part of the SCSI BUS are pulled-up.
1195 This can be achieved by ENABLING the WIDE TERMINATOR portion of the SCSI
1197 The TYAN 1365 documentation revision 1.2 is not correct about such settings.
1198 (page 10, figure 3.3).
1200 14.4 Possible data corruption during a Memory Write and Invalidate
1202 This problem is described in SYMBIOS DEL 397, Part Number 69-039241, ITEM 4.
1204 In some complex situations, 53C875 chips revision <= 3 may start a PCI
1205 Write and Invalidate Command at a not cache-line-aligned 4 DWORDS boundary.
1206 This is only possible when Cache Line Size is 8 DWORDS or greater.
1207 Pentium systems use a 8 DWORDS cache line size and so are concerned by
1208 this chip bug, unlike i486 systems that use a 4 DWORDS cache line size.
1210 When this situation occurs, the chip may complete the Write and Invalidate
1211 command after having only filled part of the last cache line involved in
1212 the transfer, leaving to data corruption the remainder of this cache line.
1214 Not using Write And Invalidate obviously gets rid of this chip bug, and so
1215 it is now the default setting of the driver.
1216 However, for people like me who want to enable this feature, I have added
1217 part of a work-around suggested by SYMBIOS. This work-around resets the
1218 addressing logic when the DATA IN phase is entered and so prevents the bug
1219 from being triggered for the first SCSI MOVE of the phase. This work-around
1220 should be enough according to the following:
1222 The only driver internal data structure that is greater than 8 DWORDS and
1223 that is moved by the SCRIPTS processor is the 'CCB header' that contains
1224 the context of the SCSI transfer. This data structure is aligned on 8 DWORDS
1225 boundary (Pentium Cache Line Size), and so is immune to this chip bug, at
1226 least on Pentium systems.
1227 But the conditions of this bug can be met when a SCSI read command is
1228 performed using a buffer that is 4 DWORDS but not cache-line aligned.
1229 This cannot happen under Linux when scatter/gather lists are used since
1230 they only refer to system buffers that are well aligned. So, a work around
1231 may only be needed under Linux when a scatter/gather list is not used and
1232 when the SCSI DATA IN phase is reentered after a phase mismatch.
1234 14.5 IRQ sharing problems
1236 When an IRQ is shared by devices that are handled by different drivers, it
1237 may happen that one driver complains about the request of the IRQ having
1238 failed. Inder Linux-2.0, this may be due to one driver having requested the
1239 IRQ using the IRQF_DISABLED flag but some other having requested the same IRQ
1240 without this flag. Under both Linux-2.0 and linux-2.2, this may be caused by
1241 one driver not having requested the IRQ with the IRQF_SHARED flag.
1243 By default, the ncr53c8xx and sym53c8xx drivers request IRQs with both the
1244 IRQF_DISABLED and the IRQF_SHARED flag under Linux-2.0 and with only the IRQF_SHARED
1245 flag under Linux-2.2.
1247 Under Linux-2.0, you can disable use of IRQF_DISABLED flag from the boot
1248 command line by using the following option:
1250 ncr53c8xx=irqm:0x20 (for the generic ncr53c8xx driver)
1251 sym53c8xx=irqm:0x20 (for the sym53c8xx driver)
1253 If this does not fix the problem, then you may want to check how all other
1254 drivers are requesting the IRQ and report the problem. Note that if at least
1255 a single driver does not request the IRQ with the IRQF_SHARED flag (share IRQ),
1256 then the request of the IRQ obviously will not succeed for all the drivers.
1258 15. SCSI problem troubleshooting
1260 15.1 Problem tracking
1262 Most SCSI problems are due to a non conformant SCSI bus or to buggy
1263 devices. If unfortunately you have SCSI problems, you can check the
1267 - terminations at both end of the SCSI chain
1268 - linux syslog messages (some of them may help you)
1270 If you do not find the source of problems, you can configure the
1271 driver with no features enabled.
1273 - only asynchronous data transfers
1274 - tagged commands disabled
1275 - disconnections not allowed
1277 Now, if your SCSI bus is ok, your system have every chance to work
1278 with this safe configuration but performances will not be optimal.
1280 If it still fails, then you can send your problem description to
1281 appropriate mailing lists or news-groups. Send me a copy in order to
1282 be sure I will receive it. Obviously, a bug in the driver code is
1285 My email address: Gerard Roudier <groudier@free.fr>
1287 Allowing disconnections is important if you use several devices on
1288 your SCSI bus but often causes problems with buggy devices.
1289 Synchronous data transfers increases throughput of fast devices like
1290 hard disks. Good SCSI hard disks with a large cache gain advantage of
1291 tagged commands queuing.
1293 Try to enable one feature at a time with control commands. For example:
1295 - echo "setsync all 25" >/proc/scsi/ncr53c8xx/0
1296 Will enable fast synchronous data transfer negotiation for all targets.
1298 - echo "setflag 3" >/proc/scsi/ncr53c8xx/0
1299 Will reset flags (no_disc) for target 3, and so will allow it to disconnect
1302 - echo "settags 3 8" >/proc/scsi/ncr53c8xx/0
1303 Will enable tagged command queuing for target 3 if that device supports it.
1305 Once you have found the device and the feature that cause problems, just
1306 disable that feature for that device.
1308 15.2 Understanding hardware error reports
1310 When the driver detects an unexpected error condition, it may display a
1311 message of the following pattern.
1313 sym53c876-0:1: ERROR (0:48) (1-21-65) (f/95) @ (script 7c0:19000000).
1314 sym53c876-0: script cmd = 19000000
1315 sym53c876-0: regdump: da 10 80 95 47 0f 01 07 75 01 81 21 80 01 09 00.
1317 Some fields in such a message may help you understand the cause of the
1318 problem, as follows:
1320 sym53c876-0:1: ERROR (0:48) (1-21-65) (f/95) @ (script 7c0:19000000).
1321 ............A.........B.C....D.E..F....G.H.......I.....J...K.......
1323 Field A : target number.
1324 SCSI ID of the device the controller was talking with at the moment the
1327 Field 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.
1340 Field 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
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.
1359 For fields D,E,F,G and H, you may look into the sym53c8xx_defs.h file
1360 that contains some minimal comments on IO register bits.
1361 Field 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.
1364 Field E : SBCL Scsi Bus Control Lines
1365 Actual value of control lines on the SCSI BUS.
1366 Field F : SBDL Scsi Bus Data Lines
1367 Actual value of data lines on the SCSI BUS.
1368 Field G : SXFER SCSI Transfer
1369 Contains the setting of the Synchronous Period for output and
1370 the current Synchronous offset (offset 0 means asynchronous).
1371 Field H : SCNTL3 Scsi Control Register 3
1372 Contains the setting of timing values for both asynchronous and
1373 synchronous data transfers.
1375 Understanding Fields I, J, K and dumps requires to have good knowledge of
1376 SCSI standards, chip cores functionnals and internal driver data structures.
1377 You are not required to decode and understand them, unless you want to help
1378 maintain the driver code.
1380 16. Synchronous transfer negotiation tables
1382 Tables below have been created by calling the routine the driver uses
1383 for synchronisation negotiation timing calculation and chip setting.
1384 The first table corresponds to Ultra chips 53875 and 53C860 with 80 MHz
1385 clock and 5 clock divisors.
1386 The second one has been calculated by setting the scsi clock to 40 Mhz
1387 and using 4 clock divisors and so applies to all NCR53C8XX chips in fast
1390 Periods are in nano-seconds and speeds are in Mega-transfers per second.
1391 1 Mega-transfers/second means 1 MB/s with 8 bits SCSI and 2 MB/s with
1394 16.1 Synchronous timings for 53C895, 53C875 and 53C860 SCSI controllers
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
1442 16.2 Synchronous timings for fast SCSI-2 53C8XX controllers
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
1475 17. Serial NVRAM (added by Richard Waltham: dormouse@farsrobt.demon.co.uk)
1479 Enabling serial NVRAM support enables detection of the serial NVRAM included
1480 on Symbios and some Symbios compatible host adaptors, and Tekram boards. The
1481 serial NVRAM is used by Symbios and Tekram to hold set up parameters for the
1482 host adaptor and its attached drives.
1484 The Symbios NVRAM also holds data on the boot order of host adaptors in a
1485 system with more than one host adaptor. This enables the order of scanning
1486 the cards for drives to be changed from the default used during host adaptor
1489 This can be done to a limited extent at the moment using "reverse probe" but
1490 this only changes the order of detection of different types of cards. The
1491 NVRAM boot order settings can do this as well as change the order the same
1492 types of cards are scanned in, something "reverse probe" cannot do.
1494 Tekram boards using Symbios chips, DC390W/F/U, which have NVRAM are detected
1495 and this is used to distinguish between Symbios compatible and Tekram host
1496 adaptors. This is used to disable the Symbios compatible "diff" setting
1497 incorrectly set on Tekram boards if the CONFIG_SCSI_53C8XX_SYMBIOS_COMPAT
1498 configuration parameter is set enabling both Symbios and Tekram boards to be
1499 used together with the Symbios cards using all their features, including
1500 "diff" support. ("led pin" support for Symbios compatible cards can remain
1501 enabled when using Tekram cards. It does nothing useful for Tekram host
1502 adaptors but does not cause problems either.)
1505 17.2 Symbios NVRAM layout
1507 typical data at NVRAM address 0x100 (53c810a NVRAM)
1508 -----------------------------------------------------------
1513 00 30 00 00 00 00 07 00 00 00 00 00 00 00 07 04 10 04 00 00
1515 04 00 0f 00 00 10 00 50 00 00 01 00 00 62
1516 04 00 03 00 00 10 00 58 00 00 01 00 00 63
1517 04 00 01 00 00 10 00 48 00 00 01 00 00 61
1518 00 00 00 00 00 00 00 00 00 00 00 00 00 00
1520 0f 00 08 08 64 00 0a 00
1521 0f 00 08 08 64 00 0a 00
1522 0f 00 08 08 64 00 0a 00
1523 0f 00 08 08 64 00 0a 00
1524 0f 00 08 08 64 00 0a 00
1525 0f 00 08 08 64 00 0a 00
1526 0f 00 08 08 64 00 0a 00
1527 0f 00 08 08 64 00 0a 00
1529 0f 00 08 08 64 00 0a 00
1530 0f 00 08 08 64 00 0a 00
1531 0f 00 08 08 64 00 0a 00
1532 0f 00 08 08 64 00 0a 00
1533 0f 00 08 08 64 00 0a 00
1534 0f 00 08 08 64 00 0a 00
1535 0f 00 08 08 64 00 0a 00
1536 0f 00 08 08 64 00 0a 00
1538 00 00 00 00 00 00 00 00
1539 00 00 00 00 00 00 00 00
1540 00 00 00 00 00 00 00 00
1541 00 00 00 00 00 00 00 00
1542 00 00 00 00 00 00 00 00
1543 00 00 00 00 00 00 00 00
1544 00 00 00 00 00 00 00 00
1545 00 00 00 00 00 00 00 00
1547 00 00 00 00 00 00 00 00
1548 00 00 00 00 00 00 00 00
1549 00 00 00 00 00 00 00 00
1550 00 00 00 00 00 00 00 00
1551 00 00 00 00 00 00 00 00
1552 00 00 00 00 00 00 00 00
1553 00 00 00 00 00 00 00 00
1554 00 00 00 00 00 00 00 00
1556 00 00 00 00 00 00 00 00
1557 00 00 00 00 00 00 00 00
1558 00 00 00 00 00 00 00 00
1563 -----------------------------------------------------------
1564 NVRAM layout details
1566 NVRAM Address 0x000-0x0ff not used
1567 0x100-0x26f initialised data
1568 0x270-0x7ff not used
1573 data - 356 bytes (checksum is byte sum of this data)
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)
1587 -----------------------------------------------------------
1590 00 00 - ?? start marker
1591 64 01 - byte count (lsb/msb excludes header/trailer)
1592 8e 0b - checksum (lsb/msb excludes header/trailer)
1593 -----------------------------------------------------------
1596 00 30 00 00 00 00 07 00 00 00 00 00 00 00 07 04 10 04 00 00
1600 | | --Removable Media Support
1602 | | 0x01 = Bootable Device
1603 | | 0x02 = All with Media
1606 | 0x00000001= scan order hi->low
1607 | (default 0x00 - scan low->hi)
1609 0x00000001 scam enable
1610 0x00000010 parity enable
1611 0x00000100 verbose boot msgs
1613 remaining bytes unknown - they do not appear to change in my
1614 current set up for any of the controllers.
1616 default set up is identical for 53c810a and 53c875 NVRAM
1617 (Removable Media added Symbios BIOS version 4.09)
1618 -----------------------------------------------------------
1621 boot order set by order of the devices in this table
1623 04 00 0f 00 00 10 00 50 00 00 01 00 00 62 -- 1st controller
1624 04 00 03 00 00 10 00 58 00 00 01 00 00 63 2nd controller
1625 04 00 01 00 00 10 00 48 00 00 01 00 00 61 3rd controller
1626 00 00 00 00 00 00 00 00 00 00 00 00 00 00 4th controller
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)
1634 ?? use of this data is a guess but seems reasonable
1636 remaining bytes unknown - they do not appear to change in my
1639 default set up is identical for 53c810a and 53c875 NVRAM
1640 -----------------------------------------------------------
1641 device set up (up to 16 devices - includes controller)
1643 0f 00 08 08 64 00 0a 00 - id 0
1644 0f 00 08 08 64 00 0a 00
1645 0f 00 08 08 64 00 0a 00
1646 0f 00 08 08 64 00 0a 00
1647 0f 00 08 08 64 00 0a 00
1648 0f 00 08 08 64 00 0a 00
1649 0f 00 08 08 64 00 0a 00
1650 0f 00 08 08 64 00 0a 00
1652 0f 00 08 08 64 00 0a 00
1653 0f 00 08 08 64 00 0a 00
1654 0f 00 08 08 64 00 0a 00
1655 0f 00 08 08 64 00 0a 00
1656 0f 00 08 08 64 00 0a 00
1657 0f 00 08 08 64 00 0a 00
1658 0f 00 08 08 64 00 0a 00
1659 0f 00 08 08 64 00 0a 00 - id 15
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)
1672 0x00000001 - disconnect enabled
1673 0x00000010 - scan at boot time
1674 0x00000100 - scan luns
1675 0x00001000 - queue tags enabled
1677 remaining bytes unknown - they do not appear to change in my
1680 ?? use of this data is a guess but seems reasonable
1681 (but it could be max bus width)
1683 default set up for 53c810a NVRAM
1684 default set up for 53c875 NVRAM - bus width - 0x10
1685 - sync offset ? - 0x10
1686 - sync period - 0x30
1687 -----------------------------------------------------------
1688 ?? spare device space (32 bit bus ??)
1690 00 00 00 00 00 00 00 00 (19x8bytes)
1693 00 00 00 00 00 00 00 00
1695 default set up is identical for 53c810a and 53c875 NVRAM
1696 -----------------------------------------------------------
1699 fe fe - ? end marker ?
1703 default set up is identical for 53c810a and 53c875 NVRAM
1704 -----------------------------------------------------------
1708 17.3 Tekram NVRAM layout
1710 nvram 64x16 (1024 bit)
1714 Drive ID 0-15 (addr 0x0yyyy0 = device setup, yyyy = ID)
1715 (addr 0x0yyyy1 = 0x0000)
1717 x x x x x x x x x x x x x x x x
1719 | | | | | | | | ----- parity check 0 - off
1720 | | | | | | | | 1 - on
1722 | | | | | | | ------- sync neg 0 - off
1723 | | | | | | | 1 - on
1725 | | | | | | --------- disconnect 0 - off
1728 | | | | | ----------- start cmd 0 - off
1731 | | | | -------------- tagged cmds 0 - off
1734 | | | ---------------- wide neg 0 - off
1737 --------------------------- sync rate 0 - 10.0 Mtrans/sec
1753 Host flags 0 (addr 0x100000, 32)
1755 x x x x x x x x x x x x x x x x
1756 | | | | | | | | | | | |
1757 | | | | | | | | ----------- host ID 0x00 - 0x0f
1759 | | | | | | | ----------------------- support for 0 - off
1760 | | | | | | | > 2 drives 1 - on
1762 | | | | | | ------------------------- support drives 0 - off
1763 | | | | | | > 1Gbytes 1 - on
1765 | | | | | --------------------------- bus reset on 0 - off
1766 | | | | | power on 1 - on
1768 | | | | ----------------------------- active neg 0 - off
1771 | | | -------------------------------- imm seek 0 - off
1774 | | ---------------------------------- scan luns 0 - off
1777 -------------------------------------- removable 0 - disable
1778 as BIOS dev 1 - boot device
1781 Host flags 1 (addr 0x100001, 33)
1783 x x x x x x x x x x x x x x x x
1785 | | | --------- boot delay 0 - 3 sec
1793 --------------------------- max tag cmds 0 - 2
1799 Host flags 2 (addr 0x100010, 34)
1801 x x x x x x x x x x x x x x x x
1803 ----- F2/F6 enable 0 - off ???
1806 checksum (addr 0x111111)
1808 checksum = 0x1234 - (sum addr 0-63)
1810 ----------------------------------------------------------------------------
1814 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
1815 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
1816 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
1817 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
1819 0x0f07 0x0400 0x0001 0x0000 0x0000 0x0000 0x0000 0x0000
1820 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000
1821 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000
1822 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0xfbbc
1825 18. Support for Big Endian
1827 The PCI local bus has been primarily designed for x86 architecture.
1828 As a consequence, PCI devices generally expect DWORDS using little endian
1833 In order to support NCR chips on a Big Endian architecture the driver has to
1834 perform byte reordering each time it is needed. This feature has been
1835 added to the driver by Cort <cort@cs.nmt.edu> and is available in driver
1836 version 2.5 and later ones. For the moment Big Endian support has only
1837 been tested on Linux/PPC (PowerPC).
1839 18.2 NCR chip in Big Endian mode of operations
1841 It can be read in SYMBIOS documentation that some chips support a special
1842 Big Endian mode, on paper: 53C815, 53C825A, 53C875, 53C875N, 53C895.
1843 This mode of operations is not software-selectable, but needs pin named
1844 BigLit to be pulled-up. Using this mode, most of byte reorderings should
1845 be avoided when the driver is running on a Big Endian CPU.
1846 Driver version 2.5 is also, in theory, ready for this feature.
1848 ===============================================================================
1849 End of NCR53C8XX driver README file