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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
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+The Linux NCR53C8XX/SYM53C8XX drivers README file
+
+Written by Gerard Roudier <groudier@free.fr>
+21 Rue Carnot
+95170 DEUIL LA BARRE - FRANCE
+
+29 May 1999
+===============================================================================
+
+1. Introduction
+2. Supported chips and SCSI features
+3. Advantages of the enhanced 896 driver
+ 3.1 Optimized SCSI SCRIPTS
+ 3.2 New features of the SYM53C896 (64 bit PCI dual LVD SCSI controller)
+4. Memory mapped I/O versus normal I/O
+5. Tagged command queueing
+6. Parity checking
+7. Profiling information
+8. Control commands
+ 8.1 Set minimum synchronous period
+ 8.2 Set wide size
+ 8.3 Set maximum number of concurrent tagged commands
+ 8.4 Set order type for tagged command
+ 8.5 Set debug mode
+ 8.6 Clear profile counters
+ 8.7 Set flag (no_disc)
+ 8.8 Set verbose level
+ 8.9 Reset all logical units of a target
+ 8.10 Abort all tasks of all logical units of a target
+9. Configuration parameters
+10. Boot setup commands
+ 10.1 Syntax
+ 10.2 Available arguments
+ 10.2.1 Master parity checking
+ 10.2.2 Scsi parity checking
+ 10.2.3 Scsi disconnections
+ 10.2.4 Special features
+ 10.2.5 Ultra SCSI support
+ 10.2.6 Default number of tagged commands
+ 10.2.7 Default synchronous period factor
+ 10.2.8 Negotiate synchronous with all devices
+ 10.2.9 Verbosity level
+ 10.2.10 Debug mode
+ 10.2.11 Burst max
+ 10.2.12 LED support
+ 10.2.13 Max wide
+ 10.2.14 Differential mode
+ 10.2.15 IRQ mode
+ 10.2.16 Reverse probe
+ 10.2.17 Fix up PCI configuration space
+ 10.2.18 Serial NVRAM
+ 10.2.19 Check SCSI BUS
+ 10.2.20 Exclude a host from being attached
+ 10.2.21 Suggest a default SCSI id for hosts
+ 10.2.22 Enable use of IMMEDIATE ARBITRATION
+ 10.3 Advised boot setup commands
+ 10.4 PCI configuration fix-up boot option
+ 10.5 Serial NVRAM support boot option
+ 10.6 SCSI BUS checking boot option
+ 10.7 IMMEDIATE ARBITRATION boot option
+11. Some constants and flags of the ncr53c8xx.h header file
+12. Installation
+13. Architecture dependent features
+14. Known problems
+ 14.1 Tagged commands with Iomega Jaz device
+ 14.2 Device names change when another controller is added
+ 14.3 Using only 8 bit devices with a WIDE SCSI controller.
+ 14.4 Possible data corruption during a Memory Write and Invalidate
+ 14.5 IRQ sharing problems
+15. SCSI problem troubleshooting
+ 15.1 Problem tracking
+ 15.2 Understanding hardware error reports
+16. Synchonous transfer negotiation tables
+ 16.1 Synchronous timings for 53C875 and 53C860 Ultra-SCSI controllers
+ 16.2 Synchronous timings for fast SCSI-2 53C8XX controllers
+17. Serial NVRAM support (by Richard Waltham)
+ 17.1 Features
+ 17.2 Symbios NVRAM layout
+ 17.3 Tekram NVRAM layout
+18. Support for Big Endian
+ 18.1 Big Endian CPU
+ 18.2 NCR chip in Big Endian mode of operations
+
+===============================================================================
+
+1. Introduction
+
+The initial Linux ncr53c8xx driver has been a port of the ncr driver from
+FreeBSD that has been achieved in November 1995 by:
+ Gerard Roudier <groudier@free.fr>
+
+The original driver has been written for 386bsd and FreeBSD by:
+ Wolfgang Stanglmeier <wolf@cologne.de>
+ Stefan Esser <se@mi.Uni-Koeln.de>
+
+It is now available as a bundle of 2 drivers:
+
+- ncr53c8xx generic driver that supports all the SYM53C8XX family including
+ the ealiest 810 rev. 1, the latest 896 (2 channel LVD SCSI controller) and
+ the new 895A (1 channel LVD SCSI controller).
+- sym53c8xx enhanced driver (a.k.a. 896 drivers) that drops support of oldest
+ chips in order to gain advantage of new features, as LOAD/STORE intructions
+ available since the 810A and hardware phase mismatch available with the
+ 896 and the 895A.
+
+You can find technical information about the NCR 8xx family in the
+PCI-HOWTO written by Michael Will and in the SCSI-HOWTO written by
+Drew Eckhardt.
+
+Information about new chips is available at LSILOGIC web server:
+
+ http://www.lsilogic.com/
+
+SCSI standard documentations are available at SYMBIOS ftp server:
+
+ ftp://ftp.symbios.com/
+
+Usefull SCSI tools written by Eric Youngdale are available at tsx-11:
+
+ ftp://tsx-11.mit.edu/pub/linux/ALPHA/scsi/scsiinfo-X.Y.tar.gz
+ ftp://tsx-11.mit.edu/pub/linux/ALPHA/scsi/scsidev-X.Y.tar.gz
+
+These tools are not ALPHA but quite clean and work quite well.
+It is essential you have the 'scsiinfo' package.
+
+This short documentation describes the features of the generic and enhanced
+drivers, configuration parameters and control commands available through
+the proc SCSI file system read / write operations.
+
+This driver has been tested OK with linux/i386, Linux/Alpha and Linux/PPC.
+
+Latest driver version and patches are available at:
+
+ ftp://ftp.tux.org/pub/people/gerard-roudier
+or
+ ftp://ftp.symbios.com/mirror/ftp.tux.org/pub/tux/roudier/drivers
+
+I am not a native speaker of English and there are probably lots of
+mistakes in this README file. Any help will be welcome.
+
+
+2. Supported chips and SCSI features
+
+The following features are supported for all chips:
+
+ Synchronous negotiation
+ Disconnection
+ Tagged command queuing
+ SCSI parity checking
+ Master parity checking
+
+"Wide negotiation" is supported for chips that allow it. The
+following table shows some characteristics of NCR 8xx family chips
+and what drivers support them.
+
+ Supported by Supported by
+ On board the generic the enhanced
+Chip SDMS BIOS Wide SCSI std. Max. sync driver driver
+---- --------- ---- --------- ---------- ------------ -------------
+810 N N FAST10 10 MB/s Y N
+810A N N FAST10 10 MB/s Y Y
+815 Y N FAST10 10 MB/s Y N
+825 Y Y FAST10 20 MB/s Y N
+825A Y Y FAST10 20 MB/s Y Y
+860 N N FAST20 20 MB/s Y Y
+875 Y Y FAST20 40 MB/s Y Y
+876 Y Y FAST20 40 MB/s Y Y
+895 Y Y FAST40 80 MB/s Y Y
+895A Y Y FAST40 80 MB/s Y Y
+896 Y Y FAST40 80 MB/s Y Y
+897 Y Y FAST40 80 MB/s Y Y
+1510D Y Y FAST40 80 MB/s Y Y
+1010 Y Y FAST80 160 MB/s N Y
+1010_66* Y Y FAST80 160 MB/s N Y
+
+* Chip supports 33MHz and 66MHz PCI buses.
+
+
+Summary of other supported features:
+
+Module: allow to load the driver
+Memory mapped I/O: increases performance
+Profiling information: read operations from the proc SCSI file system
+Control commands: write operations to the proc SCSI file system
+Debugging information: written to syslog (expert only)
+Scatter / gather
+Shared interrupt
+Boot setup commands
+Serial NVRAM: Symbios and Tekram formats
+
+
+3. Advantages of the enhanced 896 driver
+
+3.1 Optimized SCSI SCRIPTS.
+
+The 810A, 825A, 875, 895, 896 and 895A support new SCSI SCRIPTS instructions
+named LOAD and STORE that allow to move up to 1 DWORD from/to an IO register
+to/from memory much faster that the MOVE MEMORY instruction that is supported
+by the 53c7xx and 53c8xx family.
+The LOAD/STORE instructions support absolute and DSA relative addressing
+modes. The SCSI SCRIPTS had been entirely rewritten using LOAD/STORE instead
+of MOVE MEMORY instructions.
+
+3.2 New features of the SYM53C896 (64 bit PCI dual LVD SCSI controller)
+
+The 896 and the 895A allows handling of the phase mismatch context from
+SCRIPTS (avoids the phase mismatch interrupt that stops the SCSI processor
+until the C code has saved the context of the transfer).
+Implementing this without using LOAD/STORE instructions would be painfull
+and I did'nt even want to try it.
+
+The 896 chip supports 64 bit PCI transactions and addressing, while the
+895A supports 32 bit PCI transactions and 64 bit addressing.
+The SCRIPTS processor of these chips is not true 64 bit, but uses segment
+registers for bit 32-63. Another interesting feature is that LOAD/STORE
+instructions that address the on-chip RAM (8k) remain internal to the chip.
+
+Due to the use of LOAD/STORE SCRIPTS instructions, this driver does not
+support the following chips:
+- SYM53C810 revision < 0x10 (16)
+- SYM53C815 all revisions
+- SYM53C825 revision < 0x10 (16)
+
+4. Memory mapped I/O versus normal I/O
+
+Memory mapped I/O has less latency than normal I/O. Since
+linux-1.3.x, memory mapped I/O is used rather than normal I/O. Memory
+mapped I/O seems to work fine on most hardware configurations, but
+some poorly designed motherboards may break this feature.
+
+The configuration option CONFIG_SCSI_NCR53C8XX_IOMAPPED forces the
+driver to use normal I/O in all cases.
+
+
+5. Tagged command queueing
+
+Queuing more than 1 command at a time to a device allows it to perform
+optimizations based on actual head positions and its mechanical
+characteristics. This feature may also reduce average command latency.
+In order to really gain advantage of this feature, devices must have
+a reasonable cache size (No miracle is to be expected for a low-end
+hard disk with 128 KB or less).
+Some kown SCSI devices do not properly support tagged command queuing.
+Generally, firmware revisions that fix this kind of problems are available
+at respective vendor web/ftp sites.
+All I can say is that the hard disks I use on my machines behave well with
+this driver with tagged command queuing enabled:
+
+- IBM S12 0662
+- Conner 1080S
+- Quantum Atlas I
+- Quantum Atlas II
+
+If your controller has NVRAM, you can configure this feature per target
+from the user setup tool. The Tekram Setup program allows to tune the
+maximum number of queued commands up to 32. The Symbios Setup only allows
+to enable or disable this feature.
+
+The maximum number of simultaneous tagged commands queued to a device
+is currently set to 8 by default. This value is suitable for most SCSI
+disks. With large SCSI disks (>= 2GB, cache >= 512KB, average seek time
+<= 10 ms), using a larger value may give better performances.
+
+The sym53c8xx driver supports up to 255 commands per device, and the
+generic ncr53c8xx driver supports up to 64, but using more than 32 is
+generally not worth-while, unless you are using a very large disk or disk
+array. It is noticeable that most of recent hard disks seem not to accept
+more than 64 simultaneous commands. So, using more than 64 queued commands
+is probably just resource wasting.
+
+If your controller does not have NVRAM or if it is managed by the SDMS
+BIOS/SETUP, you can configure tagged queueing feature and device queue
+depths from the boot command-line. For example:
+
+ ncr53c8xx=tags:4/t2t3q15-t4q7/t1u0q32
+
+will set tagged commands queue depths as follow:
+
+- target 2 all luns on controller 0 --> 15
+- target 3 all luns on controller 0 --> 15
+- target 4 all luns on controller 0 --> 7
+- target 1 lun 0 on controller 1 --> 32
+- all other target/lun --> 4
+
+In some special conditions, some SCSI disk firmwares may return a
+QUEUE FULL status for a SCSI command. This behaviour is managed by the
+driver using the following heuristic:
+
+- Each time a QUEUE FULL status is returned, tagged queue depth is reduced
+ to the actual number of disconnected commands.
+
+- Every 1000 successfully completed SCSI commands, if allowed by the
+ current limit, the maximum number of queueable commands is incremented.
+
+Since QUEUE FULL status reception and handling is resource wasting, the
+driver notifies by default this problem to user by indicating the actual
+number of commands used and their status, as well as its decision on the
+device queue depth change.
+The heuristic used by the driver in handling QUEUE FULL ensures that the
+impact on performances is not too bad. You can get rid of the messages by
+setting verbose level to zero, as follow:
+
+1st method: boot your system using 'ncr53c8xx=verb:0' option.
+2nd method: apply "setverbose 0" control command to the proc fs entry
+ corresponding to your controller after boot-up.
+
+6. Parity checking
+
+The driver supports SCSI parity checking and PCI bus master parity
+checking. These features must be enabled in order to ensure safe data
+transfers. However, some flawed devices or mother boards will have
+problems with parity. You can disable either PCI parity or SCSI parity
+checking by entering appropriate options from the boot command line.
+(See 10: Boot setup commands).
+
+7. Profiling information
+
+Profiling information is available through the proc SCSI file system.
+Since gathering profiling information may impact performances, this
+feature is disabled by default and requires a compilation configuration
+option to be set to Y.
+
+The device associated with a host has the following pathname:
+
+ /proc/scsi/ncr53c8xx/N (N=0,1,2 ....)
+
+Generally, only 1 board is used on hardware configuration, and that device is:
+ /proc/scsi/ncr53c8xx/0
+
+However, if the driver has been made as module, the number of the
+hosts is incremented each time the driver is loaded.
+
+In order to display profiling information, just enter:
+
+ cat /proc/scsi/ncr53c8xx/0
+
+and you will get something like the following text:
+
+-------------------------------------------------------
+General information:
+ Chip NCR53C810, device id 0x1, revision id 0x2
+ IO port address 0x6000, IRQ number 10
+ Using memory mapped IO at virtual address 0x282c000
+ Synchronous transfer period 25, max commands per lun 4
+Profiling information:
+ num_trans = 18014
+ num_kbytes = 671314
+ num_disc = 25763
+ num_break = 1673
+ num_int = 1685
+ num_fly = 18038
+ ms_setup = 4940
+ ms_data = 369940
+ ms_disc = 183090
+ ms_post = 1320
+-------------------------------------------------------
+
+General information is easy to understand. The device ID and the
+revision ID identify the SCSI chip as follows:
+
+Chip Device id Revision Id
+---- --------- -----------
+810 0x1 < 0x10
+810A 0x1 >= 0x10
+815 0x4
+825 0x3 < 0x10
+860 0x6
+825A 0x3 >= 0x10
+875 0xf
+895 0xc
+
+The profiling information is updated upon completion of SCSI commands.
+A data structure is allocated and zeroed when the host adapter is
+attached. So, if the driver is a module, the profile counters are
+cleared each time the driver is loaded. The "clearprof" command
+allows you to clear these counters at any time.
+
+The following counters are available:
+
+("num" prefix means "number of",
+"ms" means milli-seconds)
+
+num_trans
+ Number of completed commands
+ Example above: 18014 completed commands
+
+num_kbytes
+ Number of kbytes transferred
+ Example above: 671 MB transferred
+
+num_disc
+ Number of SCSI disconnections
+ Example above: 25763 SCSI disconnections
+
+num_break
+ number of script interruptions (phase mismatch)
+ Example above: 1673 script interruptions
+
+num_int
+ Number of interrupts other than "on the fly"
+ Example above: 1685 interruptions not "on the fly"
+
+num_fly
+ Number of interrupts "on the fly"
+ Example above: 18038 interruptions "on the fly"
+
+ms_setup
+ Elapsed time for SCSI commands setups
+ Example above: 4.94 seconds
+
+ms_data
+ Elapsed time for data transfers
+ Example above: 369.94 seconds spent for data transfer
+
+ms_disc
+ Elapsed time for SCSI disconnections
+ Example above: 183.09 seconds spent disconnected
+
+ms_post
+ Elapsed time for command post processing
+ (time from SCSI status get to command completion call)
+ Example above: 1.32 seconds spent for post processing
+
+Due to the 1/100 second tick of the system clock, "ms_post" time may
+be wrong.
+
+In the example above, we got 18038 interrupts "on the fly" and only
+1673 script breaks generally due to disconnections inside a segment
+of the scatter list.
+
+
+8. Control commands
+
+Control commands can be sent to the driver with write operations to
+the proc SCSI file system. The generic command syntax is the
+following:
+
+ echo "<verb> <parameters>" >/proc/scsi/ncr53c8xx/0
+ (assumes controller number is 0)
+
+Using "all" for "<target>" parameter with the commands below will
+apply to all targets of the SCSI chain (except the controller).
+
+Available commands:
+
+8.1 Set minimum synchronous period factor
+
+ setsync <target> <period factor>
+
+ target: target number
+ period: minimum synchronous period.
+ Maximum speed = 1000/(4*period factor) except for special
+ cases below.
+
+ Specify a period of 255, to force asynchronous transfer mode.
+
+ 10 means 25 nano-seconds synchronous period
+ 11 means 30 nano-seconds synchronous period
+ 12 means 50 nano-seconds synchronous period
+
+8.2 Set wide size
+
+ setwide <target> <size>
+
+ target: target number
+ size: 0=8 bits, 1=16bits
+
+8.3 Set maximum number of concurrent tagged commands
+
+ settags <target> <tags>
+
+ target: target number
+ tags: number of concurrent tagged commands
+ must not be greater than SCSI_NCR_MAX_TAGS (default: 8)
+
+8.4 Set order type for tagged command
+
+ setorder <order>
+
+ order: 3 possible values:
+ simple: use SIMPLE TAG for all operations (read and write)
+ ordered: use ORDERED TAG for all operations
+ default: use default tag type,
+ SIMPLE TAG for read operations
+ ORDERED TAG for write operations
+
+
+8.5 Set debug mode
+
+ setdebug <list of debug flags>
+
+ Available debug flags:
+ alloc: print info about memory allocations (ccb, lcb)
+ queue: print info about insertions into the command start queue
+ result: print sense data on CHECK CONDITION status
+ scatter: print info about the scatter process
+ scripts: print info about the script binding process
+ tiny: print minimal debugging information
+ timing: print timing information of the NCR chip
+ nego: print information about SCSI negotiations
+ phase: print information on script interruptions
+
+ Use "setdebug" with no argument to reset debug flags.
+
+
+8.6 Clear profile counters
+
+ clearprof
+
+ The profile counters are automatically cleared when the amount of
+ data transferred reaches 1000 GB in order to avoid overflow.
+ The "clearprof" command allows you to clear these counters at any time.
+
+
+8.7 Set flag (no_disc)
+
+ setflag <target> <flag>
+
+ target: target number
+
+ For the moment, only one flag is available:
+
+ no_disc: not allow target to disconnect.
+
+ Do not specify any flag in order to reset the flag. For example:
+ - setflag 4
+ will reset no_disc flag for target 4, so will allow it disconnections.
+ - setflag all
+ will allow disconnection for all devices on the SCSI bus.
+
+
+8.8 Set verbose level
+
+ setverbose #level
+
+ The driver default verbose level is 1. This command allows to change
+ th driver verbose level after boot-up.
+
+8.9 Reset all logical units of a target
+
+ resetdev <target>
+
+ target: target number
+ The driver will try to send a BUS DEVICE RESET message to the target.
+ (Only supported by the SYM53C8XX driver and provided for test purpose)
+
+8.10 Abort all tasks of all logical units of a target
+
+ cleardev <target>
+
+ target: target number
+ The driver will try to send a ABORT message to all the logical units
+ of the target.
+ (Only supported by the SYM53C8XX driver and provided for test purpose)
+
+
+9. Configuration parameters
+
+If the firmware of all your devices is perfect enough, all the
+features supported by the driver can be enabled at start-up. However,
+if only one has a flaw for some SCSI feature, you can disable the
+support by the driver of this feature at linux start-up and enable
+this feature after boot-up only for devices that support it safely.
+
+CONFIG_SCSI_NCR53C8XX_PROFILE_SUPPORT (default answer: n)
+ This option must be set for profiling information to be gathered
+ and printed out through the proc file system. This features may
+ impact performances.
+
+CONFIG_SCSI_NCR53C8XX_IOMAPPED (default answer: n)
+ Answer "y" if you suspect your mother board to not allow memory mapped I/O.
+ May slow down performance a little. This option is required by
+ Linux/PPC and is used no matter what you select here. Linux/PPC
+ suffers no performance loss with this option since all IO is memory
+ mapped anyway.
+
+CONFIG_SCSI_NCR53C8XX_DEFAULT_TAGS (default answer: 8)
+ Default tagged command queue depth.
+
+CONFIG_SCSI_NCR53C8XX_MAX_TAGS (default answer: 8)
+ This option allows you to specify the maximum number of tagged commands
+ that can be queued to a device. The maximum supported value is 32.
+
+CONFIG_SCSI_NCR53C8XX_SYNC (default answer: 5)
+ This option allows you to specify the frequency in MHz the driver
+ will use at boot time for synchronous data transfer negotiations.
+ This frequency can be changed later with the "setsync" control command.
+ 0 means "asynchronous data transfers".
+
+CONFIG_SCSI_NCR53C8XX_FORCE_SYNC_NEGO (default answer: n)
+ Force synchronous negotiation for all SCSI-2 devices.
+ Some SCSI-2 devices do not report this feature in byte 7 of inquiry
+ response but do support it properly (TAMARACK scanners for example).
+
+CONFIG_SCSI_NCR53C8XX_NO_DISCONNECT (default and only reasonable answer: n)
+ If you suspect a device of yours does not properly support disconnections,
+ you can answer "y". Then, all SCSI devices will never disconnect the bus
+ even while performing long SCSI operations.
+
+CONFIG_SCSI_NCR53C8XX_SYMBIOS_COMPAT
+ Genuine SYMBIOS boards use GPIO0 in output for controller LED and GPIO3
+ bit as a flag indicating singled-ended/differential interface.
+ If all the boards of your system are genuine SYMBIOS boards or use
+ BIOS and drivers from SYMBIOS, you would want to enable this option.
+ This option must NOT be enabled if your system has at least one 53C8XX
+ based scsi board with a vendor-specific BIOS.
+ For example, Tekram DC-390/U, DC-390/W and DC-390/F scsi controllers
+ use a vendor-specific BIOS and are known to not use SYMBIOS compatible
+ GPIO wiring. So, this option must not be enabled if your system has
+ such a board installed.
+
+CONFIG_SCSI_NCR53C8XX_NVRAM_DETECT
+ Enable support for reading the serial NVRAM data on Symbios and
+ some Symbios compatible cards, and Tekram DC390W/U/F cards. Useful for
+ systems with more than one Symbios compatible controller where at least
+ one has a serial NVRAM, or for a system with a mixture of Symbios and
+ Tekram cards. Enables setting the boot order of host adaptors
+ to something other than the default order or "reverse probe" order.
+ Also enables Symbios and Tekram cards to be distinguished so
+ CONFIG_SCSI_NCR53C8XX_SYMBIOS_COMPAT may be set in a system with a
+ mixture of Symbios and Tekram cards so the Symbios cards can make use of
+ the full range of Symbios features, differential, led pin, without
+ causing problems for the Tekram card(s).
+
+10. Boot setup commands
+
+10.1 Syntax
+
+Setup commands can be passed to the driver either at boot time or as a
+string variable using 'insmod'.
+
+A boot setup command for the ncr53c8xx (sym53c8xx) driver begins with the
+driver name "ncr53c8xx="(sym53c8xx). The kernel syntax parser then expects
+an optionnal list of integers separated with comma followed by an optional
+list of comma-separated strings. Example of boot setup command under lilo
+prompt:
+
+lilo: linux root=/dev/hda2 ncr53c8xx=tags:4,sync:10,debug:0x200
+
+- enable tagged commands, up to 4 tagged commands queued.
+- set synchronous negotiation speed to 10 Mega-transfers / second.
+- set DEBUG_NEGO flag.
+
+Since comma seems not to be allowed when defining a string variable using
+'insmod', the driver also accepts <space> as option separator.
+The following command will install driver module with the same options as
+above.
+
+ insmod ncr53c8xx.o ncr53c8xx="tags:4 sync:10 debug:0x200"
+
+For the moment, the integer list of arguments is discarded by the driver.
+It will be used in the future in order to allow a per controller setup.
+
+Each string argument must be specified as "keyword:value". Only lower-case
+characters and digits are allowed.
+
+In a system that contains multiple 53C8xx adapters insmod will install the
+specified driver on each adapter. To exclude a chip use the 'excl' keyword.
+
+The sequence of commands,
+
+ insmod sym53c8xx sym53c8xx=excl:0x1400
+ insmod ncr53c8xx
+
+installs the sym53c8xx driver on all adapters except the one at IO port
+address 0x1400 and then installs the ncr53c8xx driver to the adapter at IO
+port address 0x1400.
+
+
+10.2 Available arguments
+
+10.2.1 Master parity checking
+ mpar:y enabled
+ mpar:n disabled
+
+10.2.2 Scsi parity checking
+ spar:y enabled
+ spar:n disabled
+
+10.2.3 Scsi disconnections
+ disc:y enabled
+ disc:n disabled
+
+10.2.4 Special features
+ Only apply to 810A, 825A, 860, 875 and 895 controllers.
+ Have no effect with other ones.
+ specf:y (or 1) enabled
+ specf:n (or 0) disabled
+ specf:3 enabled except Memory Write And Invalidate
+ The default driver setup is 'specf:3'. As a consequence, option 'specf:y'
+ must be specified in the boot setup command to enable Memory Write And
+ Invalidate.
+
+10.2.5 Ultra SCSI support
+ Only apply to 860, 875, 895, 895a, 896, 1010 and 1010_66 controllers.
+ Have no effect with other ones.
+ ultra:n All ultra speeds enabled
+ ultra:2 Ultra2 enabled
+ ultra:1 Ultra enabled
+ ultra:0 Ultra speeds disabled
+
+10.2.6 Default number of tagged commands
+ tags:0 (or tags:1 ) tagged command queuing disabled
+ tags:#tags (#tags > 1) tagged command queuing enabled
+ #tags will be truncated to the max queued commands configuration parameter.
+ This option also allows to specify a command queue depth for each device
+ that support tagged command queueing.
+ Example:
+ ncr53c8xx=tags:10/t2t3q16-t5q24/t1u2q32
+ will set devices queue depth as follow:
+ - controller #0 target #2 and target #3 -> 16 commands,
+ - controller #0 target #5 -> 24 commands,
+ - controller #1 target #1 logical unit #2 -> 32 commands,
+ - all other logical units (all targets, all controllers) -> 10 commands.
+
+10.2.7 Default synchronous period factor
+ sync:255 disabled (asynchronous transfer mode)
+ sync:#factor
+ #factor = 10 Ultra-2 SCSI 40 Mega-transfers / second
+ #factor = 11 Ultra-2 SCSI 33 Mega-transfers / second
+ #factor < 25 Ultra SCSI 20 Mega-transfers / second
+ #factor < 50 Fast SCSI-2
+
+ In all cases, the driver will use the minimum transfer period supported by
+ controllers according to NCR53C8XX chip type.
+
+10.2.8 Negotiate synchronous with all devices
+ (force sync nego)
+ fsn:y enabled
+ fsn:n disabled
+
+10.2.9 Verbosity level
+ verb:0 minimal
+ verb:1 normal
+ verb:2 too much
+
+10.2.10 Debug mode
+ debug:0 clear debug flags
+ debug:#x set debug flags
+ #x is an integer value combining the following power-of-2 values:
+ DEBUG_ALLOC 0x1
+ DEBUG_PHASE 0x2
+ DEBUG_POLL 0x4
+ DEBUG_QUEUE 0x8
+ DEBUG_RESULT 0x10
+ DEBUG_SCATTER 0x20
+ DEBUG_SCRIPT 0x40
+ DEBUG_TINY 0x80
+ DEBUG_TIMING 0x100
+ DEBUG_NEGO 0x200
+ DEBUG_TAGS 0x400
+ DEBUG_FREEZE 0x800
+ DEBUG_RESTART 0x1000
+
+ You can play safely with DEBUG_NEGO. However, some of these flags may
+ generate bunches of syslog messages.
+
+10.2.11 Burst max
+ burst:0 burst disabled
+ burst:255 get burst length from initial IO register settings.
+ burst:#x burst enabled (1<<#x burst transfers max)
+ #x is an integer value which is log base 2 of the burst transfers max.
+ The NCR53C875 and NCR53C825A support up to 128 burst transfers (#x = 7).
+ Other chips only support up to 16 (#x = 4).
+ This is a maximum value. The driver set the burst length according to chip
+ and revision ids. By default the driver uses the maximum value supported
+ by the chip.
+
+10.2.12 LED support
+ led:1 enable LED support
+ led:0 disable LED support
+ Donnot enable LED support if your scsi board does not use SDMS BIOS.
+ (See 'Configuration parameters')
+
+10.2.13 Max wide
+ wide:1 wide scsi enabled
+ wide:0 wide scsi disabled
+ Some scsi boards use a 875 (ultra wide) and only supply narrow connectors.
+ If you have connected a wide device with a 50 pins to 68 pins cable
+ converter, any accepted wide negotiation will break further data transfers.
+ In such a case, using "wide:0" in the bootup command will be helpfull.
+
+10.2.14 Differential mode
+ diff:0 never set up diff mode
+ diff:1 set up diff mode if BIOS set it
+ diff:2 always set up diff mode
+ diff:3 set diff mode if GPIO3 is not set
+
+10.2.15 IRQ mode
+ irqm:0 always open drain
+ irqm:1 same as initial settings (assumed BIOS settings)
+ irqm:2 always totem pole
+ irqm:0x10 driver will not use SA_SHIRQ flag when requesting irq
+ irqm:0x20 driver will not use SA_INTERRUPT flag when requesting irq
+
+ (Bits 0x10 and 0x20 can be combined with hardware irq mode option)
+
+10.2.16 Reverse probe
+ revprob:n probe chip ids from the PCI configuration in this order:
+ 810, 815, 820, 860, 875, 885, 895, 896
+ revprob:y probe chip ids in the reverse order.
+
+10.2.17 Fix up PCI configuration space
+ pcifix:<option bits>
+
+ Available option bits:
+ 0x0: No attempt to fix PCI configuration space registers values.
+ 0x1: Set PCI cache-line size register if not set.
+ 0x2: Set write and invalidate bit in PCI command register.
+ 0x4: Increase if necessary PCI latency timer according to burst max.
+
+ Use 'pcifix:7' in order to allow the driver to fix up all PCI features.
+
+10.2.18 Serial NVRAM
+ nvram:n do not look for serial NVRAM
+ nvram:y test controllers for onboard serial NVRAM
+ (alternate binary form)
+ mvram=<bits options>
+ 0x01 look for NVRAM (equivalent to nvram=y)
+ 0x02 ignore NVRAM "Synchronous negotiation" parameters for all devices
+ 0x04 ignore NVRAM "Wide negotiation" parameter for all devices
+ 0x08 ignore NVRAM "Scan at boot time" parameter for all devices
+ 0x80 also attach controllers set to OFF in the NVRAM (sym53c8xx only)
+
+10.2.19 Check SCSI BUS
+ buschk:<option bits>
+
+ Available option bits:
+ 0x0: No check.
+ 0x1: Check and do not attach the controller on error.
+ 0x2: Check and just warn on error.
+ 0x4: Disable SCSI bus integrity checking.
+
+10.2.20 Exclude a host from being attached
+ excl=<io_address>
+
+ Prevent host at a given io address from being attached.
+ For example 'ncr53c8xx=excl:0xb400,excl:0xc000' indicate to the
+ ncr53c8xx driver not to attach hosts at address 0xb400 and 0xc000.
+
+10.2.21 Suggest a default SCSI id for hosts
+ hostid:255 no id suggested.
+ hostid:#x (0 < x < 7) x suggested for hosts SCSI id.
+
+ If a host SCSI id is available from the NVRAM, the driver will ignore
+ any value suggested as boot option. Otherwise, if a suggested value
+ different from 255 has been supplied, it will use it. Otherwise, it will
+ try to deduce the value previously set in the hardware and use value
+ 7 if the hardware value is zero.
+
+10.2.22 Enable use of IMMEDIATE ARBITRATION
+ (only supported by the sym53c8xx driver. See 10.7 for more details)
+ iarb:0 do not use this feature.
+ iarb:#x use this feature according to bit fields as follow:
+
+ bit 0 (1) : enable IARB each time the initiator has been reselected
+ when it arbitrated for the SCSI BUS.
+ (#x >> 4) : maximum number of successive settings of IARB if the initiator
+ win arbitration and it has other commands to send to a device.
+
+Boot fail safe
+ safe:y load the following assumed fail safe initial setup
+
+ master parity disabled mpar:n
+ scsi parity enabled spar:y
+ disconnections not allowed disc:n
+ special features disabled specf:n
+ ultra scsi disabled ultra:n
+ force sync negotiation disabled fsn:n
+ reverse probe disabled revprob:n
+ PCI fix up disabled pcifix:0
+ serial NVRAM enabled nvram:y
+ verbosity level 2 verb:2
+ tagged command queuing disabled tags:0
+ synchronous negotiation disabled sync:255
+ debug flags none debug:0
+ burst length from BIOS settings burst:255
+ LED support disabled led:0
+ wide support disabled wide:0
+ settle time 10 seconds settle:10
+ differential support from BIOS settings diff:1
+ irq mode from BIOS settings irqm:1
+ SCSI BUS check do not attach on error buschk:1
+ immediate arbitration disabled iarb:0
+
+10.3 Advised boot setup commands
+
+If the driver has been configured with default options, the equivalent
+boot setup is:
+
+ ncr53c8xx=mpar:y,spar:y,disc:y,specf:3,fsn:n,ultra:2,fsn:n,revprob:n,verb:1\
+ tags:0,sync:50,debug:0,burst:7,led:0,wide:1,settle:2,diff:0,irqm:0
+
+For an installation diskette or a safe but not fast system,
+boot setup can be:
+
+ ncr53c8xx=safe:y,mpar:y,disc:y
+ ncr53c8xx=safe:y,disc:y
+ ncr53c8xx=safe:y,mpar:y
+ ncr53c8xx=safe:y
+
+My personnal system works flawlessly with the following equivalent setup:
+
+ ncr53c8xx=mpar:y,spar:y,disc:y,specf:1,fsn:n,ultra:2,fsn:n,revprob:n,verb:1\
+ tags:32,sync:12,debug:0,burst:7,led:1,wide:1,settle:2,diff:0,irqm:0
+
+The driver prints its actual setup when verbosity level is 2. You can try
+"ncr53c8xx=verb:2" to get the "static" setup of the driver, or add "verb:2"
+to your boot setup command in order to check the actual setup the driver is
+using.
+
+10.4 PCI configuration fix-up boot option
+
+pcifix:<option bits>
+
+Available option bits:
+ 0x1: Set PCI cache-line size register if not set.
+ 0x2: Set write and invalidate bit in PCI command register.
+
+Use 'pcifix:3' in order to allow the driver to fix both PCI features.
+
+These options only apply to new SYMBIOS chips 810A, 825A, 860, 875
+and 895 and are only supported for Pentium and 486 class processors.
+Recent SYMBIOS 53C8XX scsi processors are able to use PCI read multiple
+and PCI write and invalidate commands. These features require the
+cache line size register to be properly set in the PCI configuration
+space of the chips. On the other hand, chips will use PCI write and
+invalidate commands only if the corresponding bit is set to 1 in the
+PCI command register.
+
+Not all PCI bioses set the PCI cache line register and the PCI write and
+invalidate bit in the PCI configuration space of 53C8XX chips.
+Optimized PCI accesses may be broken for some PCI/memory controllers or
+make problems with some PCI boards.
+
+This fix-up worked flawlessly on my previous system.
+(MB Triton HX / 53C875 / 53C810A)
+I use these options at my own risks as you will do if you decide to
+use them too.
+
+
+10.5 Serial NVRAM support boot option
+
+nvram:n do not look for serial NVRAM
+nvram:y test controllers for onboard serial NVRAM
+
+This option can also been entered as an hexadecimal value that allows
+to control what information the driver will get from the NVRAM and what
+information it will ignore.
+For details see '17. Serial NVRAM support'.
+
+When this option is enabled, the driver tries to detect all boards using
+a Serial NVRAM. This memory is used to hold user set up parameters.
+
+The parameters the driver is able to get from the NVRAM depend on the
+data format used, as follow:
+
+ Tekram format Symbios format
+General and host parameters
+ Boot order N Y
+ Host SCSI ID Y Y
+ SCSI parity checking Y Y
+ Verbose boot messages N Y
+SCSI devices parameters
+ Synchronous transfer speed Y Y
+ Wide 16 / Narrow Y Y
+ Tagged Command Queuing enabled Y Y
+ Disconnections enabled Y Y
+ Scan at boot time N Y
+
+In order to speed up the system boot, for each device configured without
+the "scan at boot time" option, the driver forces an error on the
+first TEST UNIT READY command received for this device.
+
+Some SDMS BIOS revisions seem to be unable to boot cleanly with very fast
+hard disks. In such a situation you cannot configure the NVRAM with
+optimized parameters value.
+
+The 'nvram' boot option can be entered in hexadecimal form in order
+to ignore some options configured in the NVRAM, as follow:
+
+mvram=<bits options>
+ 0x01 look for NVRAM (equivalent to nvram=y)
+ 0x02 ignore NVRAM "Synchronous negotiation" parameters for all devices
+ 0x04 ignore NVRAM "Wide negotiation" parameter for all devices
+ 0x08 ignore NVRAM "Scan at boot time" parameter for all devices
+ 0x80 also attach controllers set to OFF in the NVRAM (sym53c8xx only)
+
+Option 0x80 is only supported by the sym53c8xx driver and is disabled by
+default. Result is that, by default (option not set), the sym53c8xx driver
+will not attach controllers set to OFF in the NVRAM.
+
+The ncr53c8xx always tries to attach all the controllers. Option 0x80 has
+not been added to the ncr53c8xx driver, since it has been reported to
+confuse users who use this driver since a long time. If you desire a
+controller not to be attached by the ncr53c8xx driver at Linux boot, you
+must use the 'excl' driver boot option.
+
+10.6 SCSI BUS checking boot option.
+
+When this option is set to a non-zero value, the driver checks SCSI lines
+logic state, 100 micro-seconds after having asserted the SCSI RESET line.
+The driver just reads SCSI lines and checks all lines read FALSE except RESET.
+Since SCSI devices shall release the BUS at most 800 nano-seconds after SCSI
+RESET has been asserted, any signal to TRUE may indicate a SCSI BUS problem.
+Unfortunately, the following common SCSI BUS problems are not detected:
+- Only 1 terminator installed.
+- Misplaced terminators.
+- Bad quality terminators.
+On the other hand, either bad cabling, broken devices, not conformant
+devices, ... may cause a SCSI signal to be wrong when te driver reads it.
+
+10.7 IMMEDIATE ARBITRATION boot option
+
+This option is only supported by the SYM53C8XX driver (not by the NCR53C8XX).
+
+SYMBIOS 53C8XX chips are able to arbitrate for the SCSI BUS as soon as they
+have detected an expected disconnection (BUS FREE PHASE). For this process
+to be started, bit 1 of SCNTL1 IO register must be set when the chip is
+connected to the SCSI BUS.
+
+When this feature has been enabled for the current connection, the chip has
+every chance to win arbitration if only devices with lower priority are
+competing for the SCSI BUS. By the way, when the chip is using SCSI id 7,
+then it will for sure win the next SCSI BUS arbitration.
+
+Since, there is no way to know what devices are trying to arbitrate for the
+BUS, using this feature can be extremely unfair. So, you are not advised
+to enable it, or at most enable this feature for the case the chip lost
+the previous arbitration (boot option 'iarb:1').
+
+This feature has the following advantages:
+
+a) Allow the initiator with ID 7 to win arbitration when it wants so.
+b) Overlap at least 4 micro-seconds of arbitration time with the execution
+ of SCRIPTS that deal with the end of the current connection and that
+ starts the next job.
+
+Hmmm... But (a) may just prevent other devices from reselecting the initiator,
+and delay data transfers or status/completions, and (b) may just waste
+SCSI BUS bandwidth if the SCRIPTS execution lasts more than 4 micro-seconds.
+
+The use of IARB needs the SCSI_NCR_IARB_SUPPORT option to have been defined
+at compile time and the 'iarb' boot option to have been set to a non zero
+value at boot time. It is not that useful for real work, but can be used
+to stress SCSI devices or for some applications that can gain advantage of
+it. By the way, if you experience badnesses like 'unexpected disconnections',
+'bad reselections', etc... when using IARB on heavy IO load, you should not
+be surprised, because force-feeding anything and blocking its arse at the
+same time cannot work for a long time. :-))
+
+
+11. Some constants and flags of the ncr53c8xx.h header file
+
+Some of these are defined from the configuration parameters. To
+change other "defines", you must edit the header file. Do that only
+if you know what you are doing.
+
+SCSI_NCR_SETUP_SPECIAL_FEATURES (default: defined)
+ If defined, the driver will enable some special features according
+ to chip and revision id.
+ For 810A, 860, 825A, 875 and 895 scsi chips, this option enables
+ support of features that reduce load of PCI bus and memory accesses
+ during scsi transfer processing: burst op-code fetch, read multiple,
+ read line, prefetch, cache line, write and invalidate,
+ burst 128 (875 only), large dma fifo (875 only), offset 16 (875 only).
+ Can be changed by the following boot setup command:
+ ncr53c8xx=specf:n
+
+SCSI_NCR_IOMAPPED (default: not defined)
+ If defined, normal I/O is forced.
+
+SCSI_NCR_SHARE_IRQ (default: defined)
+ If defined, request shared IRQ.
+
+SCSI_NCR_MAX_TAGS (default: 8)
+ Maximum number of simultaneous tagged commands to a device.
+ Can be changed by "settags <target> <maxtags>"
+
+SCSI_NCR_SETUP_DEFAULT_SYNC (default: 50)
+ Transfer period factor the driver will use at boot time for synchronous
+ negotiation. 0 means asynchronous.
+ Can be changed by "setsync <target> <period factor>"
+
+SCSI_NCR_SETUP_DEFAULT_TAGS (default: 8)
+ Default number of simultaneous tagged commands to a device.
+ < 1 means tagged command queuing disabled at start-up.
+
+SCSI_NCR_ALWAYS_SIMPLE_TAG (default: defined)
+ Use SIMPLE TAG for read and write commands.
+ Can be changed by "setorder <ordered|simple|default>"
+
+SCSI_NCR_SETUP_DISCONNECTION (default: defined)
+ If defined, targets are allowed to disconnect.
+
+SCSI_NCR_SETUP_FORCE_SYNC_NEGO (default: not defined)
+ If defined, synchronous negotiation is tried for all SCSI-2 devices.
+ Can be changed by "setsync <target> <period>"
+
+SCSI_NCR_SETUP_MASTER_PARITY (default: defined)
+ If defined, master parity checking is enabled.
+
+SCSI_NCR_SETUP_MASTER_PARITY (default: defined)
+ If defined, SCSI parity checking is enabled.
+
+SCSI_NCR_PROFILE_SUPPORT (default: not defined)
+ If defined, profiling information is gathered.
+
+SCSI_NCR_MAX_SCATTER (default: 128)
+ Scatter list size of the driver ccb.
+
+SCSI_NCR_MAX_TARGET (default: 16)
+ Max number of targets per host.
+
+SCSI_NCR_MAX_HOST (default: 2)
+ Max number of host controllers.
+
+SCSI_NCR_SETTLE_TIME (default: 2)
+ Number of seconds the driver will wait after reset.
+
+SCSI_NCR_TIMEOUT_ALERT (default: 3)
+ If a pending command will time out after this amount of seconds,
+ an ordered tag is used for the next command.
+ Avoids timeouts for unordered tagged commands.
+
+SCSI_NCR_CAN_QUEUE (default: 7*SCSI_NCR_MAX_TAGS)
+ Max number of commands that can be queued to a host.
+
+SCSI_NCR_CMD_PER_LUN (default: SCSI_NCR_MAX_TAGS)
+ Max number of commands queued to a host for a device.
+
+SCSI_NCR_SG_TABLESIZE (default: SCSI_NCR_MAX_SCATTER-1)
+ Max size of the Linux scatter/gather list.
+
+SCSI_NCR_MAX_LUN (default: 8)
+ Max number of LUNs per target.
+
+
+12. Installation
+
+This driver is part of the linux kernel distribution.
+Driver files are located in the sub-directory "drivers/scsi" of the
+kernel source tree.
+
+Driver files:
+
+ README.ncr53c8xx : this file
+ ChangeLog.ncr53c8xx : change log
+ ncr53c8xx.h : definitions
+ ncr53c8xx.c : the driver code
+
+New driver versions are made available separately in order to allow testing
+changes and new features prior to including them into the linux kernel
+distribution. The following URL provides informations on latest avalaible
+patches:
+
+ ftp://ftp.tux.org/pub/people/gerard-roudier/README
+
+
+13. Architecture dependent features.
+
+<Not yet written>
+
+
+14. Known problems
+
+14.1 Tagged commands with Iomega Jaz device
+
+I have not tried this device, however it has been reported to me the
+following: This device is capable of Tagged command queuing. However
+while spinning up, it rejects Tagged commands. This behaviour is
+conforms to 6.8.2 of SCSI-2 specifications. The current behaviour of
+the driver in that situation is not satisfying. So do not enable
+Tagged command queuing for devices that are able to spin down. The
+other problem that may appear is timeouts. The only way to avoid
+timeouts seems to edit linux/drivers/scsi/sd.c and to increase the
+current timeout values.
+
+14.2 Device names change when another controller is added.
+
+When you add a new NCR53C8XX chip based controller to a system that already
+has one or more controllers of this family, it may happen that the order
+the driver registers them to the kernel causes problems due to device
+name changes.
+When at least one controller uses NvRAM, SDMS BIOS version 4 allows you to
+define the order the BIOS will scan the scsi boards. The driver attaches
+controllers according to BIOS information if NvRAM detect option is set.
+
+If your controllers do not have NvRAM, you can:
+
+- Ask the driver to probe chip ids in reverse order from the boot command
+ line: ncr53c8xx=revprob:y
+- Make appropriate changes in the fstab.
+- Use the 'scsidev' tool from Eric Youngdale.
+
+14.3 Using only 8 bit devices with a WIDE SCSI controller.
+
+When only 8 bit NARROW devices are connected to a 16 bit WIDE SCSI controller,
+you must ensure that lines of the wide part of the SCSI BUS are pulled-up.
+This can be achieved by ENABLING the WIDE TERMINATOR portion of the SCSI
+controller card.
+The TYAN 1365 documentation revision 1.2 is not correct about such settings.
+(page 10, figure 3.3).
+
+14.4 Possible data corruption during a Memory Write and Invalidate
+
+This problem is described in SYMBIOS DEL 397, Part Number 69-039241, ITEM 4.
+
+In some complex situations, 53C875 chips revision <= 3 may start a PCI
+Write and Invalidate Command at a not cache-line-aligned 4 DWORDS boundary.
+This is only possible when Cache Line Size is 8 DWORDS or greater.
+Pentium systems use a 8 DWORDS cache line size and so are concerned by
+this chip bug, unlike i486 systems that use a 4 DWORDS cache line size.
+
+When this situation occurs, the chip may complete the Write and Invalidate
+command after having only filled part of the last cache line involved in
+the transfer, leaving to data corruption the remainder of this cache line.
+
+Not using Write And Invalidate obviously gets rid of this chip bug, and so
+it is now the default setting of the driver.
+However, for people like me who want to enable this feature, I have added
+part of a work-around suggested by SYMBIOS. This work-around resets the
+addressing logic when the DATA IN phase is entered and so prevents the bug
+from being triggered for the first SCSI MOVE of the phase. This work-around
+should be enough according to the following:
+
+The only driver internal data structure that is greater than 8 DWORDS and
+that is moved by the SCRIPTS processor is the 'CCB header' that contains
+the context of the SCSI transfer. This data structure is aligned on 8 DWORDS
+boundary (Pentium Cache Line Size), and so is immune to this chip bug, at
+least on Pentium systems.
+But the conditions of this bug can be met when a SCSI read command is
+performed using a buffer that is 4 DWORDS but not cache-line aligned.
+This cannot happen under Linux when scatter/gather lists are used since
+they only refer to system buffers that are well aligned. So, a work around
+may only be needed under Linux when a scatter/gather list is not used and
+when the SCSI DATA IN phase is reentered after a phase mismatch.
+
+14.5 IRQ sharing problems
+
+When an IRQ is shared by devices that are handled by different drivers, it
+may happen that one driver complains about the request of the IRQ having
+failed. Inder Linux-2.0, this may be due to one driver having requested the
+IRQ using the SA_INTERRUPT flag but some other having requested the same IRQ
+without this flag. Under both Linux-2.0 and linux-2.2, this may be caused by
+one driver not having requested the IRQ with the SA_SHIRQ flag.
+
+By default, the ncr53c8xx and sym53c8xx drivers request IRQs with both the
+SA_INTERRUPT and the SA_SHIRQ flag under Linux-2.0 and with only the SA_SHIRQ
+flag under Linux-2.2.
+
+Under Linux-2.0, you can disable use of SA_INTERRUPT flag from the boot
+command line by using the following option:
+
+ ncr53c8xx=irqm:0x20 (for the generic ncr53c8xx driver)
+ sym53c8xx=irqm:0x20 (for the sym53c8xx driver)
+
+If this does not fix the problem, then you may want to check how all other
+drivers are requesting the IRQ and report the problem. Note that if at least
+a single driver does not request the IRQ with the SA_SHIRQ flag (share IRQ),
+then the request of the IRQ obviously will not succeed for all the drivers.
+
+15. SCSI problem troubleshooting
+
+15.1 Problem tracking
+
+Most SCSI problems are due to a non conformant SCSI bus or to buggy
+devices. If infortunately you have SCSI problems, you can check the
+following things:
+
+- SCSI bus cables
+- terminations at both end of the SCSI chain
+- linux syslog messages (some of them may help you)
+
+If you do not find the source of problems, you can configure the
+driver with no features enabled.
+
+- only asynchronous data transfers
+- tagged commands disabled
+- disconnections not allowed
+
+Now, if your SCSI bus is ok, your system have every chance to work
+with this safe configuration but performances will not be optimal.
+
+If it still fails, then you can send your problem description to
+appropriate mailing lists or news-groups. Send me a copy in order to
+be sure I will receive it. Obviously, a bug in the driver code is
+possible.
+
+ My email address: Gerard Roudier <groudier@free.fr>
+
+Allowing disconnections is important if you use several devices on
+your SCSI bus but often causes problems with buggy devices.
+Synchronous data transfers increases throughput of fast devices like
+hard disks. Good SCSI hard disks with a large cache gain advantage of
+tagged commands queuing.
+
+Try to enable one feature at a time with control commands. For example:
+
+- echo "setsync all 25" >/proc/scsi/ncr53c8xx/0
+ Will enable fast synchronous data transfer negotiation for all targets.
+
+- echo "setflag 3" >/proc/scsi/ncr53c8xx/0
+ Will reset flags (no_disc) for target 3, and so will allow it to disconnect
+ the SCSI Bus.
+
+- echo "settags 3 8" >/proc/scsi/ncr53c8xx/0
+ Will enable tagged command queuing for target 3 if that device supports it.
+
+Once you have found the device and the feature that cause problems, just
+disable that feature for that device.
+
+15.2 Understanding hardware error reports
+
+When the driver detects an unexpected error condition, it may display a
+message of the following pattern.
+
+sym53c876-0:1: ERROR (0:48) (1-21-65) (f/95) @ (script 7c0:19000000).
+sym53c876-0: script cmd = 19000000
+sym53c876-0: regdump: da 10 80 95 47 0f 01 07 75 01 81 21 80 01 09 00.
+
+Some fields in such a message may help you understand the cause of the
+problem, as follows:
+
+sym53c876-0:1: ERROR (0:48) (1-21-65) (f/95) @ (script 7c0:19000000).
+............A.........B.C....D.E..F....G.H.......I.....J...K.......
+
+Field A : target number.
+ SCSI ID of the device the controller was talking with at the moment the
+ error occurs.
+
+Field B : DSTAT io register (DMA STATUS)
+ Bit 0x40 : MDPE Master Data Parity Error
+ Data parity error detected on the PCI BUS.
+ Bit 0x20 : BF Bus Fault
+ PCI bus fault condition detected
+ Bit 0x01 : IID Illegal Instruction Detected
+ Set by the chip when it detects an Illegal Instruction format
+ on some condition that makes an instruction illegal.
+ Bit 0x80 : DFE Dma Fifo Empty
+ Pure status bit that does not indicate an error.
+ If the reported DSTAT value contains a combination of MDPE (0x40),
+ BF (0x20), then the cause may be likely due to a PCI BUS problem.
+
+Field C : SIST io register (SCSI Interrupt Status)
+ Bit 0x08 : SGE SCSI GROSS ERROR
+ Indicates that the chip detected a severe error condition
+ on the SCSI BUS that prevents the SCSI protocol from functioning
+ properly.
+ Bit 0x04 : UDC Unexpected Disconnection
+ Indicates that the device released the SCSI BUS when the chip
+ was not expecting this to happen. A device may behave so to
+ indicate the SCSI initiator that an error condition not reportable using the SCSI protocol has occurred.
+ Bit 0x02 : RST SCSI BUS Reset
+ Generally SCSI targets do not reset the SCSI BUS, although any
+ device on the BUS can reset it at any time.
+ Bit 0x01 : PAR Parity
+ SCSI parity error detected.
+ On a faulty SCSI BUS, any error condition among SGE (0x08), UDC (0x04) and
+ PAR (0x01) may be detected by the chip. If your SCSI system sometimes
+ encounters such error conditions, especially SCSI GROSS ERROR, then a SCSI
+ BUS problem is likely the cause of these errors.
+
+For fields D,E,F,G and H, you may look into the sym53c8xx_defs.h file
+that contains some minimal comments on IO register bits.
+Field D : SOCL Scsi Output Control Latch
+ This register reflects the state of the SCSI control lines the
+ chip want to drive or compare against.
+Field E : SBCL Scsi Bus Control Lines
+ Actual value of control lines on the SCSI BUS.
+Field F : SBDL Scsi Bus Data Lines
+ Actual value of data lines on the SCSI BUS.
+Field G : SXFER SCSI Transfer
+ Contains the setting of the Synchronous Period for output and
+ the current Synchronous offset (offset 0 means asynchronous).
+Field H : SCNTL3 Scsi Control Register 3
+ Contains the setting of timing values for both asynchronous and
+ synchronous data transfers.
+
+Understanding Fields I, J, K and dumps requires to have good knowledge of
+SCSI standards, chip cores functionnals and internal driver data structures.
+You are not required to decode and understand them, unless you want to help
+maintain the driver code.
+
+16. Synchonous transfer negotiation tables
+
+Tables below have been created by calling the routine the driver uses
+for synchronisation negotiation timing calculation and chip setting.
+The first table corresponds to Ultra chips 53875 and 53C860 with 80 MHz
+clock and 5 clock divisors.
+The second one has been calculated by setting the scsi clock to 40 Mhz
+and using 4 clock divisors and so applies to all NCR53C8XX chips in fast
+SCSI-2 mode.
+
+Periods are in nano-seconds and speeds are in Mega-transfers per second.
+1 Mega-transfers/second means 1 MB/s with 8 bits SCSI and 2 MB/s with
+Wide16 SCSI.
+
+16.1 Synchronous timings for 53C895, 53C875 and 53C860 SCSI controllers
+
+ ----------------------------------------------
+ Negotiated NCR settings
+ Factor Period Speed Period Speed
+ ------ ------ ------ ------ ------
+ 10 25 40.000 25 40.000 (53C895 only)
+ 11 30.2 33.112 31.25 32.000 (53C895 only)
+ 12 50 20.000 50 20.000
+ 13 52 19.230 62 16.000
+ 14 56 17.857 62 16.000
+ 15 60 16.666 62 16.000
+ 16 64 15.625 75 13.333
+ 17 68 14.705 75 13.333
+ 18 72 13.888 75 13.333
+ 19 76 13.157 87 11.428
+ 20 80 12.500 87 11.428
+ 21 84 11.904 87 11.428
+ 22 88 11.363 93 10.666
+ 23 92 10.869 93 10.666
+ 24 96 10.416 100 10.000
+ 25 100 10.000 100 10.000
+ 26 104 9.615 112 8.888
+ 27 108 9.259 112 8.888
+ 28 112 8.928 112 8.888
+ 29 116 8.620 125 8.000
+ 30 120 8.333 125 8.000
+ 31 124 8.064 125 8.000
+ 32 128 7.812 131 7.619
+ 33 132 7.575 150 6.666
+ 34 136 7.352 150 6.666
+ 35 140 7.142 150 6.666
+ 36 144 6.944 150 6.666
+ 37 148 6.756 150 6.666
+ 38 152 6.578 175 5.714
+ 39 156 6.410 175 5.714
+ 40 160 6.250 175 5.714
+ 41 164 6.097 175 5.714
+ 42 168 5.952 175 5.714
+ 43 172 5.813 175 5.714
+ 44 176 5.681 187 5.333
+ 45 180 5.555 187 5.333
+ 46 184 5.434 187 5.333
+ 47 188 5.319 200 5.000
+ 48 192 5.208 200 5.000
+ 49 196 5.102 200 5.000
+
+
+16.2 Synchronous timings for fast SCSI-2 53C8XX controllers
+
+ ----------------------------------------------
+ Negotiated NCR settings
+ Factor Period Speed Period Speed
+ ------ ------ ------ ------ ------
+ 25 100 10.000 100 10.000
+ 26 104 9.615 125 8.000
+ 27 108 9.259 125 8.000
+ 28 112 8.928 125 8.000
+ 29 116 8.620 125 8.000
+ 30 120 8.333 125 8.000
+ 31 124 8.064 125 8.000
+ 32 128 7.812 131 7.619
+ 33 132 7.575 150 6.666
+ 34 136 7.352 150 6.666
+ 35 140 7.142 150 6.666
+ 36 144 6.944 150 6.666
+ 37 148 6.756 150 6.666
+ 38 152 6.578 175 5.714
+ 39 156 6.410 175 5.714
+ 40 160 6.250 175 5.714
+ 41 164 6.097 175 5.714
+ 42 168 5.952 175 5.714
+ 43 172 5.813 175 5.714
+ 44 176 5.681 187 5.333
+ 45 180 5.555 187 5.333
+ 46 184 5.434 187 5.333
+ 47 188 5.319 200 5.000
+ 48 192 5.208 200 5.000
+ 49 196 5.102 200 5.000
+
+
+17. Serial NVRAM (added by Richard Waltham: dormouse@farsrobt.demon.co.uk)
+
+17.1 Features
+
+Enabling serial NVRAM support enables detection of the serial NVRAM included
+on Symbios and some Symbios compatible host adaptors, and Tekram boards. The
+serial NVRAM is used by Symbios and Tekram to hold set up parameters for the
+host adaptor and it's attached drives.
+
+The Symbios NVRAM also holds data on the boot order of host adaptors in a
+system with more than one host adaptor. This enables the order of scanning
+the cards for drives to be changed from the default used during host adaptor
+detection.
+
+This can be done to a limited extent at the moment using "reverse probe" but
+this only changes the order of detection of different types of cards. The
+NVRAM boot order settings can do this as well as change the order the same
+types of cards are scanned in, something "reverse probe" cannot do.
+
+Tekram boards using Symbios chips, DC390W/F/U, which have NVRAM are detected
+and this is used to distinguish between Symbios compatible and Tekram host
+adaptors. This is used to disable the Symbios compatible "diff" setting
+incorrectly set on Tekram boards if the CONFIG_SCSI_53C8XX_SYMBIOS_COMPAT
+configuration parameter is set enabling both Symbios and Tekram boards to be
+used together with the Symbios cards using all their features, including
+"diff" support. ("led pin" support for Symbios compatible cards can remain
+enabled when using Tekram cards. It does nothing useful for Tekram host
+adaptors but does not cause problems either.)
+
+
+17.2 Symbios NVRAM layout
+
+typical data at NVRAM address 0x100 (53c810a NVRAM)
+-----------------------------------------------------------
+00 00
+64 01
+8e 0b
+
+00 30 00 00 00 00 07 00 00 00 00 00 00 00 07 04 10 04 00 00
+
+04 00 0f 00 00 10 00 50 00 00 01 00 00 62
+04 00 03 00 00 10 00 58 00 00 01 00 00 63
+04 00 01 00 00 10 00 48 00 00 01 00 00 61
+00 00 00 00 00 00 00 00 00 00 00 00 00 00
+
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+
+00 00 00 00 00 00 00 00
+00 00 00 00 00 00 00 00
+00 00 00 00 00 00 00 00
+00 00 00 00 00 00 00 00
+00 00 00 00 00 00 00 00
+00 00 00 00 00 00 00 00
+00 00 00 00 00 00 00 00
+00 00 00 00 00 00 00 00
+
+00 00 00 00 00 00 00 00
+00 00 00 00 00 00 00 00
+00 00 00 00 00 00 00 00
+00 00 00 00 00 00 00 00
+00 00 00 00 00 00 00 00
+00 00 00 00 00 00 00 00
+00 00 00 00 00 00 00 00
+00 00 00 00 00 00 00 00
+
+00 00 00 00 00 00 00 00
+00 00 00 00 00 00 00 00
+00 00 00 00 00 00 00 00
+
+fe fe
+00 00
+00 00
+-----------------------------------------------------------
+NVRAM layout details
+
+NVRAM Address 0x000-0x0ff not used
+ 0x100-0x26f initialised data
+ 0x270-0x7ff not used
+
+general layout
+
+ header - 6 bytes,
+ data - 356 bytes (checksum is byte sum of this data)
+ trailer - 6 bytes
+ ---
+ total 368 bytes
+
+data area layout
+
+ controller set up - 20 bytes
+ boot configuration - 56 bytes (4x14 bytes)
+ device set up - 128 bytes (16x8 bytes)
+ unused (spare?) - 152 bytes (19x8 bytes)
+ ---
+ total 356 bytes
+
+-----------------------------------------------------------
+header
+
+00 00 - ?? start marker
+64 01 - byte count (lsb/msb excludes header/trailer)
+8e 0b - checksum (lsb/msb excludes header/trailer)
+-----------------------------------------------------------
+controller set up
+
+00 30 00 00 00 00 07 00 00 00 00 00 00 00 07 04 10 04 00 00
+ | | | |
+ | | | -- host ID
+ | | |
+ | | --Removable Media Support
+ | | 0x00 = none
+ | | 0x01 = Bootable Device
+ | | 0x02 = All with Media
+ | |
+ | --flag bits 2
+ | 0x00000001= scan order hi->low
+ | (default 0x00 - scan low->hi)
+ --flag bits 1
+ 0x00000001 scam enable
+ 0x00000010 parity enable
+ 0x00000100 verbose boot msgs
+
+remaining bytes unknown - they do not appear to change in my
+current set up for any of the controllers.
+
+default set up is identical for 53c810a and 53c875 NVRAM
+(Removable Media added Symbios BIOS version 4.09)
+-----------------------------------------------------------
+boot configuration
+
+boot order set by order of the devices in this table
+
+04 00 0f 00 00 10 00 50 00 00 01 00 00 62 -- 1st controller
+04 00 03 00 00 10 00 58 00 00 01 00 00 63 2nd controller
+04 00 01 00 00 10 00 48 00 00 01 00 00 61 3rd controller
+00 00 00 00 00 00 00 00 00 00 00 00 00 00 4th controller
+ | | | | | | | |
+ | | | | | | ---- PCI io port adr
+ | | | | | --0x01 init/scan at boot time
+ | | | | --PCI device/function number (0xdddddfff)
+ | | ----- ?? PCI vendor ID (lsb/msb)
+ ----PCI device ID (lsb/msb)
+
+?? use of this data is a guess but seems reasonable
+
+remaining bytes unknown - they do not appear to change in my
+current set up
+
+default set up is identical for 53c810a and 53c875 NVRAM
+-----------------------------------------------------------
+device set up (up to 16 devices - includes controller)
+
+0f 00 08 08 64 00 0a 00 - id 0
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00
+0f 00 08 08 64 00 0a 00 - id 15
+ | | | | | |
+ | | | | ----timeout (lsb/msb)
+ | | | --synch period (0x?? 40 Mtrans/sec- fast 40) (probably 0x28)
+ | | | (0x30 20 Mtrans/sec- fast 20)
+ | | | (0x64 10 Mtrans/sec- fast )
+ | | | (0xc8 5 Mtrans/sec)
+ | | | (0x00 asynchronous)
+ | | -- ?? max sync offset (0x08 in NVRAM on 53c810a)
+ | | (0x10 in NVRAM on 53c875)
+ | --device bus width (0x08 narrow)
+ | (0x10 16 bit wide)
+ --flag bits
+ 0x00000001 - disconnect enabled
+ 0x00000010 - scan at boot time
+ 0x00000100 - scan luns
+ 0x00001000 - queue tags enabled
+
+remaining bytes unknown - they do not appear to change in my
+current set up
+
+?? use of this data is a guess but seems reasonable
+(but it could be max bus width)
+
+default set up for 53c810a NVRAM
+default set up for 53c875 NVRAM - bus width - 0x10
+ - sync offset ? - 0x10
+ - sync period - 0x30
+-----------------------------------------------------------
+?? spare device space (32 bit bus ??)
+
+00 00 00 00 00 00 00 00 (19x8bytes)
+.
+.
+00 00 00 00 00 00 00 00
+
+default set up is identical for 53c810a and 53c875 NVRAM
+-----------------------------------------------------------
+trailer
+
+fe fe - ? end marker ?
+00 00
+00 00
+
+default set up is identical for 53c810a and 53c875 NVRAM
+-----------------------------------------------------------
+
+
+
+17.3 Tekram NVRAM layout
+
+nvram 64x16 (1024 bit)
+
+Drive settings
+
+Drive ID 0-15 (addr 0x0yyyy0 = device setup, yyyy = ID)
+ (addr 0x0yyyy1 = 0x0000)
+
+ x x x x x x x x x x x x x x x x
+ | | | | | | | | |
+ | | | | | | | | ----- parity check 0 - off
+ | | | | | | | | 1 - on
+ | | | | | | | |
+ | | | | | | | ------- sync neg 0 - off
+ | | | | | | | 1 - on
+ | | | | | | |
+ | | | | | | --------- disconnect 0 - off
+ | | | | | | 1 - on
+ | | | | | |
+ | | | | | ----------- start cmd 0 - off
+ | | | | | 1 - on
+ | | | | |
+ | | | | -------------- tagged cmds 0 - off
+ | | | | 1 - on
+ | | | |
+ | | | ---------------- wide neg 0 - off
+ | | | 1 - on
+ | | |
+ --------------------------- sync rate 0 - 10.0 Mtrans/sec
+ 1 - 8.0
+ 2 - 6.6
+ 3 - 5.7
+ 4 - 5.0
+ 5 - 4.0
+ 6 - 3.0
+ 7 - 2.0
+ 7 - 2.0
+ 8 - 20.0
+ 9 - 16.7
+ a - 13.9
+ b - 11.9
+
+Global settings
+
+Host flags 0 (addr 0x100000, 32)
+
+ x x x x x x x x x x x x x x x x
+ | | | | | | | | | | | |
+ | | | | | | | | ----------- host ID 0x00 - 0x0f
+ | | | | | | | |
+ | | | | | | | ----------------------- support for 0 - off
+ | | | | | | | > 2 drives 1 - on
+ | | | | | | |
+ | | | | | | ------------------------- support drives 0 - off
+ | | | | | | > 1Gbytes 1 - on
+ | | | | | |
+ | | | | | --------------------------- bus reset on 0 - off
+ | | | | | power on 1 - on
+ | | | | |
+ | | | | ----------------------------- active neg 0 - off
+ | | | | 1 - on
+ | | | |
+ | | | -------------------------------- imm seek 0 - off
+ | | | 1 - on
+ | | |
+ | | ---------------------------------- scan luns 0 - off
+ | | 1 - on
+ | |
+ -------------------------------------- removable 0 - disable
+ as BIOS dev 1 - boot device
+ 2 - all
+
+Host flags 1 (addr 0x100001, 33)
+
+ x x x x x x x x x x x x x x x x
+ | | | | | |
+ | | | --------- boot delay 0 - 3 sec
+ | | | 1 - 5
+ | | | 2 - 10
+ | | | 3 - 20
+ | | | 4 - 30
+ | | | 5 - 60
+ | | | 6 - 120
+ | | |
+ --------------------------- max tag cmds 0 - 2
+ 1 - 4
+ 2 - 8
+ 3 - 16
+ 4 - 32
+
+Host flags 2 (addr 0x100010, 34)
+
+ x x x x x x x x x x x x x x x x
+ |
+ ----- F2/F6 enable 0 - off ???
+ 1 - on ???
+
+checksum (addr 0x111111)
+
+checksum = 0x1234 - (sum addr 0-63)
+
+----------------------------------------------------------------------------
+
+default nvram data:
+
+0x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
+0x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
+0x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
+0x0037 0x0000 0x0037 0x0000 0x0037 0x0000 0x0037 0x0000
+
+0x0f07 0x0400 0x0001 0x0000 0x0000 0x0000 0x0000 0x0000
+0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000
+0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000
+0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0xfbbc
+
+
+18. Support for Big Endian
+
+The PCI local bus has been primarily designed for x86 architecture.
+As a consequence, PCI devices generally expect DWORDS using little endian
+byte ordering.
+
+18.1 Big Endian CPU
+
+In order to support NCR chips on a Big Endian architecture the driver has to
+perform byte reordering each time it is needed. This feature has been
+added to the driver by Cort <cort@cs.nmt.edu> and is available in driver
+version 2.5 and later ones. For the moment Big Endian support has only
+been tested on Linux/PPC (PowerPC).
+
+18.2 NCR chip in Big Endian mode of operations
+
+It can be read in SYMBIOS documentation that some chips support a special
+Big Endian mode, on paper: 53C815, 53C825A, 53C875, 53C875N, 53C895.
+This mode of operations is not software-selectable, but needs pin named
+BigLit to be pulled-up. Using this mode, most of byte reorderings should
+be avoided when the driver is running on a Big Endian CPU.
+Driver version 2.5 is also, in theory, ready for this feature.
+
+===============================================================================
+End of NCR53C8XX driver README file