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diff --git a/Documentation/scsi/ncr53c8xx.rst b/Documentation/scsi/ncr53c8xx.rst new file mode 100644 index 000000000000..fd8d26dc5dab --- /dev/null +++ b/Documentation/scsi/ncr53c8xx.rst @@ -0,0 +1,2169 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=========================== +NCR53C8XX/SYM53C8XX drivers +=========================== + +Written by Gerard Roudier <groudier@free.fr> + +21 Rue Carnot + +95170 DEUIL LA BARRE - FRANCE + +29 May 1999 + +.. Contents: + + 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. Synchronous 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 earliest 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 instructions + 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/ + +Useful 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 | +|[1]_ | | | | | | | ++--------+-----------+-----+-----------+------------+------------+------------+ + +.. [1] 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) +:Serial NVRAM: Symbios and Tekram formats + +- Scatter / gather +- Shared interrupt +- Boot setup commands + + +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 painful +and I didn't 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 known 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_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 optional 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 + ===== =================== + + Do not 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 helpful. + +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 IRQF_SHARED 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 personal 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 | Y | Y | +| enabled | | | ++-------------------------------+------------------+--------------+ +| * 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 the 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_SCSI_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 information on latest available +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. + +15. SCSI problem troubleshooting +================================ + +15.1 Problem tracking +--------------------- + +Most SCSI problems are due to a non conformant SCSI bus or to 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 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. Synchronous 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 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 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. |