scsi: docs: convert sym53c8xx_2.txt to ReST

Link: https://lore.kernel.org/r/08202c87294d61d147ec4ac784219d20805cdeb5.1583136624.git.mchehab+huawei@kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 0 insertions, 1048 deletions

diff --git a/Documentation/scsi/sym53c8xx_2.txt b/Documentation/scsi/sym53c8xx_2.txt
deleted file mode 100644
index d28186553fb0..000000000000
--- a/Documentation/scsi/sym53c8xx_2.txt
+++ /dev/null
@@ -1,1048 +0,0 @@
-The Linux SYM-2 driver documentation file
-
-Written by Gerard Roudier <groudier@free.fr>
-21 Rue Carnot
-95170 DEUIL LA BARRE - FRANCE
-
-Updated by Matthew Wilcox <matthew@wil.cx>
-
-2004-10-09
-===============================================================================
-
-1.  Introduction
-2.  Supported chips and SCSI features
-3.  Advantages of this driver for newer chips.
-      3.1 Optimized SCSI SCRIPTS
-      3.2 New features appeared with the SYM53C896
-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 debug mode
-      8.5  Set flag (no_disc)
-      8.6  Set verbose level
-      8.7  Reset all logical units of a target
-      8.8  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  Default number of tagged commands
-             10.2.2  Burst max
-             10.2.3  LED support
-             10.2.4  Differential mode
-             10.2.5  IRQ mode
-             10.2.6  Check SCSI BUS 
-             10.2.7  Suggest a default SCSI id for hosts
-             10.2.8  Verbosity level
-             10.2.9  Debug mode
-             10.2.10 Settle delay
-             10.2.11 Serial NVRAM
-             10.2.12 Exclude a host from being attached
-      10.3 Converting from old options
-      10.4 SCSI BUS checking boot option
-11. SCSI problem troubleshooting
-      15.1 Problem tracking
-      15.2 Understanding hardware error reports
-12. Serial NVRAM support (by Richard Waltham)
-      17.1 Features
-      17.2 Symbios NVRAM layout
-      17.3 Tekram  NVRAM layout
-
-===============================================================================
-
-1. Introduction
-
-This driver supports the whole SYM53C8XX family of PCI-SCSI controllers.
-It also support the subset of LSI53C10XX PCI-SCSI controllers that are based 
-on the SYM53C8XX SCRIPTS language.
-
-It replaces the sym53c8xx+ncr53c8xx driver bundle and shares its core code 
-with the FreeBSD SYM-2 driver. The `glue' that allows this driver to work 
-under Linux is contained in 2 files named sym_glue.h and sym_glue.c.
-Other drivers files are intended not to depend on the Operating System 
-on which the driver is used.
-
-The history of this driver can be summarized as follows:
-
-1993: ncr driver written for 386bsd and FreeBSD by:
-          Wolfgang Stanglmeier        <wolf@cologne.de>
-          Stefan Esser                <se@mi.Uni-Koeln.de>
-
-1996: port of the ncr driver to Linux-1.2.13 and rename it ncr53c8xx.
-          Gerard Roudier
-
-1998: new sym53c8xx driver for Linux based on LOAD/STORE instruction and that 
-      adds full support for the 896 but drops support for early NCR devices.
-          Gerard Roudier
-
-1999: port of the sym53c8xx driver to FreeBSD and support for the LSI53C1010 
-      33 MHz and 66MHz Ultra-3 controllers. The new driver is named `sym'.
-          Gerard Roudier
-
-2000: Add support for early NCR devices to FreeBSD `sym' driver.
-      Break the driver into several sources and separate the OS glue 
-      code from the core code that can be shared among different O/Ses.
-      Write a glue code for Linux.
-          Gerard Roudier
-
-2004: Remove FreeBSD compatibility code.  Remove support for versions of
-      Linux before 2.6.  Start using Linux facilities.
-
-This README file addresses the Linux version of the driver. Under FreeBSD, 
-the driver documentation is the sym.8 man page.
-
-Information about new chips is available at LSILOGIC web server:
-
-          http://www.lsilogic.com/
-
-SCSI standard documentations are available at T10 site:
-
-          http://www.t10.org/
-
-Useful SCSI tools written by Eric Youngdale are part of most Linux 
-distributions:
-   scsiinfo:    command line tool
-   scsi-config: TCL/Tk tool using scsiinfo
-
-2. Supported chips and SCSI features
-
-The following features are supported for all chips:
-
-	Synchronous negotiation
-	Disconnection
-	Tagged command queuing
-	SCSI parity checking
-	PCI Master parity checking
-
-Other features depends on chip capabilities.
-The driver notably uses optimized SCRIPTS for devices that support 
-LOAD/STORE and handles PHASE MISMATCH from SCRIPTS for devices that 
-support the corresponding feature.
-
-The following table shows some characteristics of the chip family.
-
-       On board                                   LOAD/STORE   HARDWARE
-Chip   SDMS BIOS   Wide   SCSI std.   Max. sync   SCRIPTS      PHASE MISMATCH
-----   ---------   ----   ---------   ----------  ----------   --------------
-810        N         N      FAST10    10 MB/s        N             N
-810A       N         N      FAST10    10 MB/s        Y             N
-815        Y         N      FAST10    10 MB/s        N             N
-825        Y         Y      FAST10    20 MB/s        N             N
-825A       Y         Y      FAST10    20 MB/s        Y             N
-860        N         N      FAST20    20 MB/s        Y             N
-875        Y         Y      FAST20    40 MB/s        Y             N
-875A       Y         Y      FAST20    40 MB/s        Y             Y
-876        Y         Y      FAST20    40 MB/s        Y             N
-895        Y         Y      FAST40    80 MB/s        Y             N
-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        Y             Y
-1010_66*   Y         Y      FAST80   160 MB/s        Y             Y
-
-* Chip supports 33MHz and 66MHz PCI bus clock.
-
-
-Summary of other supported features:
-
-Module:                allow to load the driver
-Memory mapped I/O:     increases performance
-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 this driver for newer chips.
-
-3.1 Optimized SCSI SCRIPTS.
-
-All chips except the 810, 815 and 825, 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.
-
-Due to the lack of LOAD/STORE SCRIPTS instructions by earlier chips, this 
-driver also incorporates a different SCRIPTS set based on MEMORY MOVE, in 
-order to provide support for the entire SYM53C8XX chips family.
-
-3.2 New features appeared with the SYM53C896
-
-Newer chips (see above) 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).
-
-The 896 and 1010 chips support 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.
-
-4. Memory mapped I/O versus normal I/O
-
-Memory mapped I/O has less latency than normal I/O and is the recommended 
-way for doing IO with PCI devices. Memory mapped I/O seems to work fine on 
-most hardware configurations, but some poorly designed chipsets may break 
-this feature. A configuration option is provided for normal I/O to be 
-used but the driver defaults to MMIO.
-
-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 known old 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 I never have had problem with tagged queuing using 
-this driver and its predecessors. Hard disks that behaved correctly for 
-me using tagged commands are the following:
-
-- IBM S12 0662
-- Conner 1080S
-- Quantum Atlas I
-- Quantum Atlas II
-- Seagate Cheetah I
-- Quantum Viking II
-- IBM DRVS
-- Quantum Atlas IV
-- Seagate Cheetah 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 16 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.
-
-This driver supports up to 255 commands per device, and but using more than 
-64 is generally not worth-while, unless you are using a very large disk or 
-disk arrays. 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:
-
-  sym53c8xx=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 200 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 'sym53c8xx=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.  Some flawed devices or mother boards may have problems
-with parity.  The options to defeat parity checking have been removed
-from the driver.
-
-7. Profiling information
-
-This driver does not provide profiling information as did its predecessors.
-This feature was not this useful and added complexity to the code. 
-As the driver code got more complex, I have decided to remove everything 
-that didn't seem actually useful.
-
-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/sym53c8xx/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 0, to force asynchronous transfer mode.
-
-       9 means 12.5 nano-seconds synchronous period
-      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 configured (default: 16)
-
-8.4 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.
-
-
-8.5 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.
-
-
-8.6 Set verbose level
-
-    setverbose #level
-
-    The driver default verbose level is 1. This command allows to change 
-    th driver verbose level after boot-up.
-
-8.7 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.
-
-8.8 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.
-
-
-9. Configuration parameters
-
-Under kernel configuration tools (make menuconfig, for example), it is 
-possible to change some default driver 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.
-
-Configuration parameters:
-
-Use normal IO                         (default answer: n)
-    Answer "y" if you suspect your mother board to not allow memory mapped I/O.
-    May slow down performance a little.
-
-Default tagged command queue depth    (default answer: 16)
-    Entering 0 defaults to tagged commands not being used.
-    This parameter can be specified from the boot command line.
-
-Maximum number of queued commands     (default answer: 32)
-    This option allows you to specify the maximum number of tagged commands 
-    that can be queued to a device. The maximum supported value is 255.
-
-Synchronous transfers frequency       (default answer: 80)
-    This option allows you to specify the frequency in MHz the driver 
-    will use at boot time for synchronous data transfer negotiations.
-    0 means "asynchronous data transfers".
-
-10. Boot setup commands
-
-10.1 Syntax
-
-Setup commands can be passed to the driver either at boot time or as
-parameters to modprobe, as described in Documentation/admin-guide/kernel-parameters.rst
-
-Example of boot setup command under lilo prompt:
-
-lilo: linux root=/dev/sda2 sym53c8xx.cmd_per_lun=4 sym53c8xx.sync=10 sym53c8xx.debug=0x200
-
-- enable tagged commands, up to 4 tagged commands queued.
-- set synchronous negotiation speed to 10 Mega-transfers / second.
-- set DEBUG_NEGO flag.
-
-The following command will install the driver module with the same
-options as above.
-
-    modprobe sym53c8xx cmd_per_lun=4 sync=10 debug=0x200
-
-10.2 Available arguments
-
-10.2.1  Default number of tagged commands
-        cmd_per_lun=0 (or cmd_per_lun=1) tagged command queuing disabled
-        cmd_per_lun=#tags (#tags > 1) tagged command queuing enabled
-  #tags will be truncated to the max queued commands configuration parameter.
-
-10.2.2 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.
-  By default the driver uses the maximum value supported by the chip.
-
-10.2.3 LED support
-        led=1      enable  LED support
-        led=0      disable LED support
-  Do not enable LED support if your scsi board does not use SDMS BIOS.
-  (See 'Configuration parameters')
-
-10.2.4 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
-
-10.2.5 IRQ mode
-        irqm=0     always open drain
-        irqm=1     same as initial settings (assumed BIOS settings)
-        irqm=2     always totem pole
-
-10.2.6 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.
-
-10.2.7 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.
-
-10.2.8  Verbosity level
-        verb=0     minimal
-        verb=1     normal
-        verb=2     too much
-
-10.2.9 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. 
-
-10.2.10 Settle delay
-        settle=n	delay for n seconds
-
-  After a bus reset, the driver will delay for n seconds before talking
-  to any device on the bus.  The default is 3 seconds and safe mode will
-  default it to 10.
-
-10.2.11 Serial NVRAM
-	NB: option not currently implemented.
-        nvram=n     do not look for serial NVRAM
-        nvram=y     test controllers for onboard serial NVRAM
-        (alternate binary form)
-        nvram=<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)
-
-10.2.12 Exclude a host from being attached
-        excl=<io_address>,...
-
-    Prevent host at a given io address from being attached.
-    For example 'excl=0xb400,0xc000' indicate to the 
-    driver not to attach hosts at address 0xb400 and 0xc000.
-
-10.3 Converting from old style options
-
-Previously, the sym2 driver accepted arguments of the form
-	sym53c8xx=tags:4,sync:10,debug:0x200
-
-As a result of the new module parameters, this is no longer available.
-Most of the options have remained the same, but tags has become
-cmd_per_lun to reflect its different purposes.  The sample above would
-be specified as:
-	modprobe sym53c8xx cmd_per_lun=4 sync=10 debug=0x200
-
-or on the kernel boot line as:
-	sym53c8xx.cmd_per_lun=4 sym53c8xx.sync=10 sym53c8xx.debug=0x200
-
-10.4 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.
-
-15. SCSI problem troubleshooting
-
-15.1 Problem tracking
-
-Most SCSI problems are due to a non conformant SCSI bus or too buggy
-devices.  If unfortunately 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 or devices in the NVRAM with minimal features.
-
-- only asynchronous data transfers
-- tagged commands disabled
-- disconnections not allowed
-
-Now, if your SCSI bus is ok, your system has 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 current 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.
-
-15.2 Understanding hardware error reports
-
-When the driver detects an unexpected error condition, it may display a 
-message of the following pattern.
-
-sym0:1: ERROR (0:48) (1-21-65) (f/95/0) @ (script 7c0:19000000).
-sym0: script cmd = 19000000
-sym0: 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:
-
-sym0:1: ERROR (0:48) (1-21-65) (f/95/0) @ (script 7c0:19000000).
-.....A.........B.C....D.E..F....G.H..I.......J.....K...L.......
-
-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. 
-Field I : SCNTL4 Scsi Control Register 4
-          Only meaningful for 53C1010 Ultra3 controllers.
-
-Understanding Fields J, K, L 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.
-
-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 its 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 information is no longer used
-as it's fundamentally incompatible with the hotplug PCI model.
-
-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.)
-
-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.
-
-
-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
-
-
-===============================================================================
-End of Linux SYM-2 driver documentation file