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+The tmscsim driver
+1. Purpose and history
+4. Configuration via /proc/scsi/tmscsim/?
+5. Configuration via boot/module params
+6. Potential improvements
+7. Bug reports, debugging and updates
+1. Purpose and history
+The tmscsim driver supports PCI SCSI Host Adapters based on the AM53C974
+chip. AM53C974 based SCSI adapters include:
+ Tekram DC390, DC390T
+ Dawicontrol 2974
+ QLogic Fast! PCI Basic
+ some on-board adapters
+(This is most probably not a complete list)
+It has originally written by C.L. Huang from the Tekram corp. to support the
+Tekram DC390(T) adapter. This is where the name comes from: tm = Tekram
+scsi = SCSI driver, m = AMD (?) as opposed to w for the DC390W/U/F
+(NCR53c8X5, X=2/7) driver. Yes, there was also a driver for the latter,
+tmscsiw, which supported DC390W/U/F adapters. It's not maintained any more,
+as the ncr53c8xx is perfectly supporting these adapters since some time.
+The driver first appeared in April 1996, exclusively supported the DC390
+and has been enhanced since then in various steps. In May 1998 support for
+general AM53C974 based adapters and some possibilities to configure it were
+added. The non-DC390 support works by assuming some values for the data
+normally taken from the DC390 EEPROM. See below (chapter 5) for details.
+When using the DC390, the configuration is still be done using the DC390
+BIOS setup. The DC390 EEPROM is read and used by the driver, any boot or
+module parameters (chapter 5) are ignored! However, you can change settings
+dynamically, as described in chapter 4.
+For a more detailed description of the driver's history, see the first lines
+The numbering scheme isn't consistent. The first versions went from 1.00 to
+1.12, then 1.20a to 1.20t. Finally I decided to use the ncr53c8xx scheme. So
+the next revisions will be 2.0a to 2.0X (stable), 2.1a to 2.1X (experimental),
+2.2a to 2.2X (stable, again) etc. (X = anything between a and z.) If I send
+fixes to people for testing, I create intermediate versions with a digit
+appended, e.g. 2.0c3.
+If you got any recent kernel with this driver and document included in
+linux/drivers/scsi, you basically have to do nothing special to use this
+driver. Of course you have to choose to compile SCSI support and DC390(T)
+support into your kernel or as module when configuring your kernel for
+NEW: You may as well compile this module outside your kernel, using the
+ If you got an old kernel (pre 2.1.127, pre 2.0.37p1) with an old version of
+ this driver: Get dc390-21125-20b.diff.gz or dc390-2036p21-20b1.diff.gz from
+ my web page and apply the patch. Apply further patches to upgrade to the
+ latest version of the driver.
+ If you want to do it manually, you should copy the files (dc390.h,
+ tmscsim.h, tmscsim.c, scsiiom.c and README.tmscsim) from this directory to
+ linux/drivers/scsi. You have to recompile your kernel/module of course.
+ You should apply the three patches included in dc390-120-kernel.diff
+ (Applying them: cd /usr/src; patch -p0 <~/dc390-120-kernel.diff)
+ The patches are against 2.1.125, so you might have to manually resolve
+ rejections when applying to another kernel version.
+ The patches will update the kernel startup code to allow boot parameters to
+ be passed to the driver, update the Documentation and finally offer you the
+ possibility to omit the non-DC390 parts of the driver.
+ (By selecting "Omit support for non DC390" you basically disable the
+ emulation of a DC390 EEPROM for non DC390 adapters. This saves a few bytes
+ of memory.)
+If you got a very old kernel without the tmscsim driver (pre 2.0.31)
+I recommend upgrading your kernel. However, if you don't want to, please
+contact me to get the appropriate patches.
+Upgrading a SCSI driver is always a delicate thing to do. The 2.0 driver has
+proven stable on many systems, but it's still a good idea to take some
+precautions. In an ideal world you would have a full backup of your disks.
+The world isn't ideal and most people don't have full backups (me neither).
+So take at least the following measures:
+* make your kernel remount the FS read-only on detecting an error:
+ tune2fs -e remount-ro /dev/sd??
+* have copies of your SCSI disk's partition tables on some safe location:
+ dd if=/dev/sda of=/mnt/floppy/sda bs=512 count=1
+ or just print it with:
+ fdisk -l | lpr
+* make sure you are able to boot Linux (e.g. from floppy disk using InitRD)
+ if your SCSI disk gets corrupted. You can use
+One more warning: I used to overclock my PCI bus to 41.67 MHz. My Tekram
+DC390F (Sym53c875) accepted this as well as my Millennium. But the Am53C974
+produced errors and started to corrupt my disks. So don't do that! A 37.50
+MHz PCI bus works for me, though, but I don't recommend using higher clocks
+than the 33.33 MHz being in the PCI spec.
+If you want to share the IRQ with another device and the driver refuses to
+do so, you might succeed with changing the DC390_IRQ type in tmscsim.c to
+IRQF_SHARED | IRQF_DISABLED.
+ * Tagged command queueing
+ * Sync speed up to 10 MHz
+ * Disconnection
+ * Multiple LUNs
+- General / Linux interface
+ * Support for up to 4 AM53C974 adapters.
+ * DC390 EEPROM usage or boot/module params
+ * Information via cat /proc/scsi/tmscsim/?
+ * Dynamically configurable by writing to /proc/scsi/tmscsim/?
+ * Dynamic allocation of resources
+ * SMP support: Locking on io_request lock (Linux 2.1/2.2) or adapter
+ specific locks (Linux 2.5?)
+ * Uniform source code for Linux-2.x.y
+ * Support for dyn. addition/removal of devices via add/remove-single-device
+ (Try: echo "scsi add-single-device C B T U" >/proc/scsi/scsi
+ C = Controller, B = Bus, T = Target SCSI ID, U = Unit SCSI LUN.)
+ Use with care!
+ * Try to use the partition table for the determination of the mapping
+4. Configuration via /proc/scsi/tmscsim/?
+First of all look at the output of /proc/scsi/tmscsim/? by typing
+ cat /proc/scsi/tmscsim/?
+The "?" should be replaced by the SCSI host number. (The shell might do this
+You will see some info regarding the adapter and, at the end, a listing of
+the attached devices and their settings.
+Here's an example:
+garloff@kurt:/home/garloff > cat /proc/scsi/tmscsim/0
+Tekram DC390/AM53C974 PCI SCSI Host Adapter, Driver Version 2.0e7 2000-11-28
+SCSI Host Nr 1, AM53C974 Adapter Nr 0
+IOPortBase 0xb000, IRQ 10
+MaxID 8, MaxLUN 8, AdapterID 6, SelTimeout 250 ms, DelayReset 1 s
+TagMaxNum 16, Status 0x00, ACBFlag 0x00, GlitchEater 24 ns
+Statistics: Cmnds 1470165, Cmnds not sent directly 0, Out of SRB conds 0
+ Lost arbitrations 587, Sel. connected 0, Connected: No
+Nr of attached devices: 4, Nr of DCBs: 4
+Map of attached LUNs: 01 00 00 03 01 00 00 00
+Idx ID LUN Prty Sync DsCn SndS TagQ NegoPeriod SyncSpeed SyncOffs MaxCmd
+00 00 00 Yes Yes Yes Yes Yes 100 ns 10.0 M 15 16
+01 03 00 Yes Yes Yes Yes No 100 ns 10.0 M 15 01
+02 03 01 Yes Yes Yes Yes No 100 ns 10.0 M 15 01
+03 04 00 Yes Yes Yes Yes No 100 ns 10.0 M 15 01
+Note that the settings MaxID and MaxLUN are not zero- but one-based, which
+means that a setting MaxLUN=4, will result in the support of LUNs 0..3. This
+is somehow inconvenient, but the way the mid-level SCSI code expects it to be.
+ACB and DCB are acronyms for Adapter Control Block and Device Control Block.
+These are data structures of the driver containing information about the
+adapter and the connected SCSI devices respectively.
+Idx is the device index (just a consecutive number for the driver), ID and
+LUN are the SCSI ID and LUN, Prty means Parity checking, Sync synchronous
+negotiation, DsCn Disconnection, SndS Send Start command on startup (not
+used by the driver) and TagQ Tagged Command Queueing. NegoPeriod and
+SyncSpeed are somehow redundant, because they are reciprocal values
+(1 / 112 ns = 8.9 MHz). At least in theory. The driver is able to adjust the
+NegoPeriod more accurate (4ns) than the SyncSpeed (1 / 25ns). I don't know
+if certain devices will have problems with this discrepancy. Max. speed is
+10 MHz corresp. to a min. NegoPeriod of 100 ns.
+(The driver allows slightly higher speeds if the devices (Ultra SCSI) accept
+it, but that's out of adapter spec, on your own risk and unlikely to improve
+performance. You're likely to crash your disks.)
+SyncOffs is the offset used for synchronous negotiations; max. is 15.
+The last values are only shown, if Sync is enabled. (NegoPeriod is still
+displayed in brackets to show the values which will be used after enabling
+MaxCmd ist the number of commands (=tags) which can be processed at the same
+time by the device.
+If you want to change a setting, you can do that by writing to
+/proc/scsi/tmscsim/?. Basically you have to imitate the output of driver.
+(Don't use the brackets for NegoPeriod on Sync disabled devices.)
+You don't have to care about capitalisation. The driver will accept space,
+tab, comma, = and : as separators.
+There are three kinds of changes:
+(1) Change driver settings:
+ You type the names of the parameters and the params following it.
+ echo "MaxLUN=8 seltimeout 200" >/proc/scsi/tmscsim/0
+ Note that you can only change MaxID, MaxLUN, AdapterID, SelTimeOut,
+ TagMaxNum, ACBFlag, GlitchEater and DelayReset. Don't change ACBFlag
+ unless you want to see what happens, if the driver hangs.
+(2) Change device settings: You write a config line to the driver. The Nr
+ must match the ID and LUN given. If you give "-" as parameter, it is
+ ignored and the corresponding setting won't be changed.
+ You can use "y" or "n" instead of "Yes" and "No" if you want to.
+ You don't need to specify a full line. The driver automatically performs
+ an INQUIRY on the device if necessary to check if it is capable to operate
+ with the given settings (Sync, TagQ).
+ echo "0 0 0 y y y - y - 10 " >/proc/scsi/tmscsim/0
+ echo "3 5 0 y n y " >/proc/scsi/tmscsim/0
+ To give a short explanation of the first example:
+ The first three numbers, "0 0 0" (Device index 0, SCSI ID 0, SCSI LUN 0),
+ select the device to which the following parameters apply. Note that it
+ would be sufficient to use the index or both SCSI ID and LUN, but I chose
+ to require all three to have a syntax similar to the output.
+ The following "y y y - y" enables Parity checking, enables Synchronous
+ transfers, Disconnection, leaves Send Start (not used) untouched and
+ enables Tagged Command Queueing for the selected device. The "-" skips
+ the Negotiation Period setting but the "10" sets the max sync. speed to
+ 10 MHz. It's useless to specify both NegoPeriod and SyncSpeed as
+ discussed above. The values used in this example will result in maximum
+(3) Special commands: You can force a SCSI bus reset, an INQUIRY command, the
+ removal or the addition of a device's DCB and a SCSI register dump.
+ This is only used for debugging when you meet problems. The parameter of
+ the INQUIRY and REMOVE commands is the device index as shown by the
+ output of /proc/scsi/tmscsim/? in the device listing in the first column
+ (Idx). ADD takes the SCSI ID and LUN.
+ echo "reset" >/proc/scsi/tmscsim/0
+ echo "inquiry 1" >/proc/scsi/tmscsim/0
+ echo "remove 2" >/proc/scsi/tmscsim/1
+ echo "add 2 3" >/proc/scsi/tmscsim/?
+ echo "dump" >/proc/scsi/tmscsim/0
+ Note that you will meet problems when you REMOVE a device's DCB with the
+ remove command if it contains partitions which are mounted. Only use it
+ after unmounting its partitions, telling the SCSI mid-level code to
+ remove it (scsi remove-single-device) and you really need a few bytes of
+ The ADD command allows you to configure a device before you tell the
+ mid-level code to try detection.
+I'd suggest reviewing the output of /proc/scsi/tmscsim/? after changing
+settings to see if everything changed as requested.
+5. Configuration via boot/module parameters
+With the DC390, the driver reads its EEPROM settings and tries to use them.
+But you may want to override the settings prior to being able to change the
+driver configuration via /proc/scsi/tmscsim/?.
+If you do have another AM53C974 based adapter, that's even the only
+possibility to adjust settings before you are able to write to the
+/proc/scsi/tmscsim/? pseudo-file, e.g. if you want to use another
+adapter ID than 7.
+(BTW, the log message "DC390: No EEPROM found!" is normal without a DC390.)
+For this purpose, you can pass options to the driver before it is initialised
+by using kernel or module parameters. See lilo(8) or modprobe(1) manual
+pages on how to pass params to the kernel or a module.
+[NOTE: Formerly, it was not possible to override the EEPROM supplied
+ settings of the DC390 with cmd line parameters. This has changed since
+The syntax of the params is much shorter than the syntax of the /proc/...
+interface. This makes it a little bit more difficult to use. However, long
+parameter lines have the risk to be misinterpreted and the length of kernel
+parameters is limited.
+As the support for non-DC390 adapters works by simulating the values of the
+DC390 EEPROM, the settings are given in a DC390 BIOS' way.
+Here's the syntax:
+Each of the parameters is a number, containing the described information:
+* AdaptID: The SCSI ID of the host adapter. Must be in the range 0..7
+ Default is 7.
+* SpdIdx: The index of the maximum speed as in the DC390 BIOS. The values
+ 0..7 mean 10, 8.0, 6.7, 5.7, 5.0, 4.0, 3.1 and 2 MHz resp. Default is
+ 0 (10.0 MHz).
+* DevMode is a bit mapped value describing the per-device features. It
+ applies to all devices. (Sync, Disc and TagQ will only apply, if the
+ device supports it.) The meaning of the bits (* = default):
+ Bit Val(hex) Val(dec) Meaning
+ *0 0x01 1 Parity check
+ *1 0x02 2 Synchronous Negotiation
+ *2 0x04 4 Disconnection
+ *3 0x08 8 Send Start command on startup. (Not used)
+ *4 0x10 16 Tagged Command Queueing
+ As usual, the desired value is obtained by adding the wanted values. If
+ you want to enable all values, e.g., you would use 31(0x1f). Default is 31.
+* AdaptMode is a bit mapped value describing the enabled adapter features.
+ Bit Val(hex) Val(dec) Meaning
+ *0 0x01 1 Support more than two drives. (Not used)
+ *1 0x02 2 Use DOS compatible mapping for HDs greater than 1GB.
+ *2 0x04 4 Reset SCSI Bus on startup.
+ *3 0x08 8 Active Negation: Improves SCSI Bus noise immunity.
+ 4 0x10 16 Immediate return on BIOS seek command. (Not used)
+ (*)5 0x20 32 Check for LUNs >= 1.
+ The default for LUN Check depends on CONFIG_SCSI_MULTI_LUN.
+* TaggedCmnds is a number indicating the maximum number of Tagged Commands.
+ It is the binary logarithm - 1 of the actual number. Max is 4 (32).
+ Value Number of Tagged Commands
+ 0 2
+ 1 4
+ 2 8
+ *3 16
+ 4 32
+* DelayReset is the time in seconds (minus 0.5s), the adapter waits, after a
+ bus reset. Default is 1 (corresp. to 1.5s).
+ modprobe tmscsim tmscsim=6,2,31
+would set the adapter ID to 6, max. speed to 6.7 MHz, enable all device
+features and leave the adapter features, the number of Tagged Commands
+and the Delay after a reset to the defaults.
+As you can see, you don't need to specify all of the six params.
+If you want values to be ignored (i.e. the EEprom settings or the defaults
+will be used), you may pass -2 (not 0!) at the corresponding position.
+The defaults (7,0,31,15,3,1) are aggressive to allow good performance. You
+can use tmscsim=7,0,31,63,4,0 for maximum performance, if your SCSI chain
+allows it. If you meet problems, you can use tmscsim=-1 which is a shortcut
+6. Potential improvements
+Most of the intended work on the driver has been done. Here are a few ideas
+to further improve its usability:
+* Cleanly separate per-Target and per-LUN properties (DCB)
+* More intelligent abort() routine
+* Use new_eh code (Linux-2.1+)
+* Have the mid-level (ML) code (and not the driver) handle more of the
+ various conditions.
+* Command queueing in the driver: Eliminate Query list and use ML instead.
+* More user friendly boot/module param syntax
+Further investigation on these problems:
+* Driver hangs with sync readcdda (xcdroast) (most probably VIA PCI error)
+Please see http://www.garloff.de/kurt/linux/dc390/problems.html
+* Changing the parameters of multi-lun by the tmscsim/? interface will
+ cause problems, cause these settings are mostly per Target and not per LUN
+ and should be updated accordingly. To be fixed for 2.0d24.
+* CDRs (eg Yam CRW4416) not recognized, because some buggy devices don't
+ recover from a SCSI reset in time. Use a higher delay or don't issue
+ a SCSI bus reset on driver initialization. See problems page.
+ For the CRW4416S, this seems to be solved with firmware 1.0g (reported by
+ Jean-Yves Barbier).
+* TEAC CD-532S not being recognized. (Works with 1.11).
+* Scanners (eg. Astra UMAX 1220S) don't work: Disable Sync Negotiation.
+ If this does not help, try echo "INQUIRY t" >/proc/scsi/tmscsim/? (t
+ replaced by the dev index of your scanner). You may try to reset your SCSI
+ bus afterwards (echo "RESET" >/proc/scsi/tmscsim/?).
+ The problem seems to be solved as of 2.0d18, thanks to Andreas Rick.
+* If there is a valid partition table, the driver will use it for determining
+ the mapping. If there's none, a reasonable mapping (Symbios-like) will be
+ assumed. Other operating systems may not like this mapping, though
+ it's consistent with the BIOS' behaviour. Old DC390 drivers ignored the
+ partition table and used a H/S = 64/32 or 255/63 translation. So if you
+ want to be compatible to those, use this old mapping when creating
+ partition tables. Even worse, on bootup the DC390 might complain if other
+ mappings are found, so auto rebooting may fail.
+* In some situations, the driver will get stuck in an abort loop. This is a
+ bad interaction between the Mid-Layer of Linux' SCSI code and the driver.
+ Try to disable DsCn, if you meet this problem. Please contact me for
+ further debugging.
+7. Bug reports, debugging and updates
+Whenever you have problems with the driver, you are invited to ask the
+author for help. However, I'd suggest reading the docs and trying to solve
+the problem yourself, first.
+If you find something, which you believe to be a bug, please report it to me.
+Please append the output of /proc/scsi/scsi, /proc/scsi/tmscsim/? and
+maybe the DC390 log messages to the report.
+Bug reports should be send to me (Kurt Garloff <email@example.com>) as well
+as to the linux-scsi list (<firstname.lastname@example.org>), as sometimes bugs
+are caused by the SCSI mid-level code.
+I will ask you for some more details and probably I will also ask you to
+enable some of the DEBUG options in the driver (tmscsim.c:DC390_DEBUGXXX
+defines). The driver will produce some data for the syslog facility then.
+Beware: If your syslog gets written to a SCSI disk connected to your
+AM53C974, the logging might produce log output again, and you might end
+having your box spending most of its time doing the logging.
+The latest version of the driver can be found at:
+Thanks to Linus Torvalds, Alan Cox, the FSF people, the XFree86 team and
+all the others for the wonderful OS and software.
+Thanks to C.L. Huang and Philip Giang (Tekram) for the initial driver
+release and support.
+Thanks to Doug Ledford, Gérard Roudier for support with SCSI coding.
+Thanks to a lot of people (espec. Chiaki Ishikawa, Andreas Haumer, Hubert
+Tonneau) for intensively testing the driver (and even risking data loss
+doing this during early revisions).
+Recently, SuSE GmbH, Nuernberg, FRG, has been paying me for the driver
+development and maintenance. Special thanks!
+ This driver is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; version 2 of the License.
+ If you want to use any later version of the GNU GPL, you will probably
+ be allowed to, but you have to ask me and Tekram <email@example.com>
+Written by Kurt Garloff <firstname.lastname@example.org> 1998/06/11
+Last updated 2000/11/28, driver revision 2.0e7
+$Id: README.tmscsim,v 18.104.22.168 2000/12/20 01:07:12 garloff Exp $