diff options
| author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
| commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
| tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/scsi/ibmmca.txt | |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'Documentation/scsi/ibmmca.txt')
| -rw-r--r-- | Documentation/scsi/ibmmca.txt | 1402 |
1 files changed, 1402 insertions, 0 deletions
diff --git a/Documentation/scsi/ibmmca.txt b/Documentation/scsi/ibmmca.txt new file mode 100644 index 000000000000..2814491600ff --- /dev/null +++ b/Documentation/scsi/ibmmca.txt @@ -0,0 +1,1402 @@ + + -=< The IBM Microchannel SCSI-Subsystem >=- + + for the IBM PS/2 series + + Low Level Software-Driver for Linux + + Copyright (c) 1995 Strom Systems, Inc. under the terms of the GNU + General Public License. Originally written by Martin Kolinek, December 1995. + Officially modified and maintained by Michael Lang since January 1999. + + Version 4.0a + + Last update: January 3, 2001 + + Before you Start + ---------------- + This is the common README.ibmmca file for all driver releases of the + IBM MCA SCSI driver for Linux. Please note, that driver releases 4.0 + or newer do not work with kernel versions older than 2.4.0, while driver + versions older than 4.0 do not work with kernels 2.4.0 or later! If you + try to compile your kernel with the wrong driver source, the + compilation is aborted and you get a corresponding error message. This is + no bug in the driver. It prevents you from using the wrong sourcecode + with the wrong kernel version. + + Authors of this Driver + ---------------------- + - Chris Beauregard (improvement of the SCSI-device mapping by the driver) + - Martin Kolinek (origin, first release of this driver) + - Klaus Kudielka (multiple SCSI-host management/detection, adaption to + Linux Kernel 2.1.x, module support) + - Michael Lang (assigning original pun/lun mapping, dynamical ldn + assignment, rewritten adapter detection, this file, + patches, official driver maintenance and subsequent + debugging, related with the driver) + + Table of Contents + ----------------- + 1 Abstract + 2 Driver Description + 2.1 IBM SCSI-Subsystem Detection + 2.2 Physical Units, Logical Units, and Logical Devices + 2.3 SCSI-Device Recognition and dynamical ldn Assignment + 2.4 SCSI-Device Order + 2.5 Regular SCSI-Command-Processing + 2.6 Abort & Reset Commands + 2.7 Disk Geometry + 2.8 Kernel Boot Option + 2.9 Driver Module Support + 2.10 Multiple Hostadapter Support + 2.11 /proc/scsi-Filesystem Information + 2.12 /proc/mca-Filesystem Information + 2.13 Supported IBM SCSI-Subsystems + 2.14 Linux Kernel Versions + 3 Code History + 4 To do + 5 Users' Manual + 5.1 Commandline Parameters + 5.2 Troubleshooting + 5.3 Bugreports + 5.4 Support WWW-page + 6 References + 7 Credits to + 7.1 People + 7.2 Sponsors & Supporters + 8 Trademarks + 9 Disclaimer + + * * * + + 1 Abstract + ---------- + This README-file describes the IBM SCSI-subsystem low level driver for + Linux. The descriptions which were formerly kept in the source-code have + been taken out to this file to easify the codes' readability. The driver + description has been updated, as most of the former description was already + quite outdated. The history of the driver development is also kept inside + here. Multiple historical developments have been summarized to shorten the + textsize a bit. At the end of this file you can find a small manual for + this driver and hints to get it running on your machine. + + 2 Driver Description + -------------------- + 2.1 IBM SCSI-Subsystem Detection + -------------------------------- + This is done in the ibmmca_detect() function. It first checks, if the + Microchannel-bus support is enabled, as the IBM SCSI-subsystem needs the + Microchannel. In a next step, a free interrupt is chosen and the main + interrupt handler is connected to it to handle answers of the SCSI- + subsystem(s). If the F/W SCSI-adapter is forced by the BIOS to use IRQ11 + instead of IRQ14, IRQ11 is used for the IBM SCSI-2 F/W adapter. In a + further step it is checked, if the adapter gets detected by force from + the kernel commandline, where the I/O port and the SCSI-subsystem id can + be specified. The next step checks if there is an integrated SCSI-subsystem + installed. This register area is fixed through all IBM PS/2 MCA-machines + and appears as something like a virtual slot 10 of the MCA-bus. On most + PS/2 machines, the POS registers of slot 10 are set to 0xff or 0x00 if not + integrated SCSI-controller is available. But on certain PS/2s, like model + 9595, this slot 10 is used to store other information which at earlier + stage confused the driver and resulted in the detection of some ghost-SCSI. + If POS-register 2 and 3 are not 0x00 and not 0xff, but all other POS + registers are either 0xff or 0x00, there must be an integrated SCSI- + subsystem present and it will be registered as IBM Integrated SCSI- + Subsystem. The next step checks, if there is a slot-adapter installed on + the MCA-bus. To get this, the first two POS-registers, that represent the + adapter ID are checked. If they fit to one of the ids, stored in the + adapter list, a SCSI-subsystem is assumed to be found in a slot and will be + registered. This check is done through all possible MCA-bus slots to allow + more than one SCSI-adapter to be present in the PS/2-system and this is + already the first point of problems. Looking into the technical reference + manual for the IBM PS/2 common interfaces, the POS2 register must have + different interpretation of its single bits to avoid overlapping I/O + regions. While one can assume, that the integrated subsystem has a fix + I/O-address at 0x3540 - 0x3547, further installed IBM SCSI-adapters must + use a different I/O-address. This is expressed by bit 1 to 3 of POS2 + (multiplied by 8 + 0x3540). Bits 2 and 3 are reserved for the integrated + subsystem, but not for the adapters! The following list shows, how the + bits of POS2 and POS3 should be interpreted. + + The POS2-register of all PS/2 models' integrated SCSI-subsystems has the + following interpretation of bits: + Bit 7 - 4 : Chip Revision ID (Release) + Bit 3 - 2 : Reserved + Bit 1 : 8k NVRAM Disabled + Bit 0 : Chip Enable (EN-Signal) + The POS3-register is interpreted as follows (for most IBM SCSI-subsys.): + Bit 7 - 5 : SCSI ID + Bit 4 - 0 : Reserved = 0 + The slot-adapters have different interpretation of these bits. The IBM SCSI + adapter (w/Cache) and the IBM SCSI-2 F/W adapter use the following + interpretation of the POS2 register: + Bit 7 - 4 : ROM Segment Address Select + Bit 3 - 1 : Adapter I/O Address Select (*8+0x3540) + Bit 0 : Adapter Enable (EN-Signal) + and for the POS3 register: + Bit 7 - 5 : SCSI ID + Bit 4 : Fairness Enable (SCSI ID3 f. F/W) + Bit 3 - 0 : Arbitration Level + The most modern product of the series is the IBM SCSI-2 F/W adapter, it + allows dual-bus SCSI and SCSI-wide addressing, which means, PUNs may be + between 0 and 15. Here, Bit 4 is the high-order bit of the 4-bit wide + adapter PUN expression. In short words, this means, that IBM PS/2 machines + can only support 1 single integrated subsystem by default. Additional + slot-adapters get ports assigned by the automatic configuration tool. + + One day I found a patch in ibmmca_detect(), forcing the I/O-address to be + 0x3540 for integrated SCSI-subsystems, there was a remark placed, that on + integrated IBM SCSI-subsystems of model 56, the POS2 register was showing 5. + This means, that really for these models, POS2 has to be interpreted + sticking to the technical reference guide. In this case, the bit 2 (4) is + a reserved bit and may not be interpreted. These differences between the + adapters and the integrated controllers are taken into account by the + detection routine of the driver on from version >3.0g. + + Every time, a SCSI-subsystem is discovered, the ibmmca_register() function + is called. This function checks first, if the requested area for the I/O- + address of this SCSI-subsystem is still available and assigns this I/O- + area to the SCSI-subsystem. There are always 8 sequential I/O-addresses + taken for each individual SCSI-subsystem found, which are: + + Offset Type Permissions + 0 Command Interface Register 1 Read/Write + 1 Command Interface Register 2 Read/Write + 2 Command Interface Register 3 Read/Write + 3 Command Interface Register 4 Read/Write + 4 Attention Register Read/Write + 5 Basic Control Register Read/Write + 6 Interrupt Status Register Read + 7 Basic Status Register Read + + After the I/O-address range is assigned, the host-adapter is assigned + to a local structure which keeps all adapter information needed for the + driver itself and the mid- and higher-level SCSI-drivers. The SCSI pun/lun + and the adapters' ldn tables are initialized and get probed afterwards by + the check_devices() function. If no further adapters are found, + ibmmca_detect() quits. + + 2.2 Physical Units, Logical Units, and Logical Devices + ------------------------------------------------------ + There can be up to 56 devices on the SCSI bus (besides the adapter): + there are up to 7 "physical units" (each identified by physical unit + number or pun, also called the scsi id, this is the number you select + with hardware jumpers), and each physical unit can have up to 8 + "logical units" (each identified by logical unit number, or lun, + between 0 and 7). The IBM SCSI-2 F/W adapter offers this on up to two + busses and provides support for 30 logical devices at the same time, where + in wide-addressing mode you can have 16 puns with 32 luns on each device. + This section dexribes you the handling of devices on non-F/W adapters. + Just imagine, that you can have 16 * 32 = 512 devices on a F/W adapter + which means a lot of possible devices for such a small machine. + + Typically the adapter has pun=7, so puns of other physical units + are between 0 and 6(15). On a wide-adapter a pun higher than 7 is + possible, but is normally not used. Almost all physical units have only + one logical unit, with lun=0. A CD-ROM jukebox would be an example of a + physical unit with more than one logical unit. + + The embedded microprocessor of the IBM SCSI-subsystem hides the complex + two-dimensional (pun,lun) organization from the operating system. + When the machine is powered-up (or rebooted), the embedded microprocessor + checks, on its own, all 56 possible (pun,lun) combinations, and the first + 15 devices found are assigned into a one-dimensional array of so-called + "logical devices", identified by "logical device numbers" or ldn. The last + ldn=15 is reserved for the subsystem itself. Wide adapters may have + to check up to 15 * 8 = 120 pun/lun combinations. + + 2.3 SCSI-Device Recognition and Dynamical ldn Assignment + -------------------------------------------------------- + One consequence of information hiding is that the real (pun,lun) + numbers are also hidden. The two possibilities to get around this problem + is to offer fake pun/lun combinations to the operating system or to + delete the whole mapping of the adapter and to reassign the ldns, using + the immediate assign command of the SCSI-subsystem for probing through + all possible pun/lun combinations. a ldn is a "logical device number" + which is used by IBM SCSI-subsystems to access some valid SCSI-device. + At the beginning of the development of this driver, the following approach + was used: + + First, the driver checked the ldn's (0 to 6) to find out which ldn's + have devices assigned. This was done by the functions check_devices() and + device_exists(). The interrupt handler has a special paragraph of code + (see local_checking_phase_flag) to assist in the checking. Assume, for + example, that three logical devices were found assigned at ldn 0, 1, 2. + These are presented to the upper layer of Linux SCSI driver + as devices with bogus (pun, lun) equal to (0,0), (1,0), (2,0). + On the other hand, if the upper layer issues a command to device + say (4,0), this driver returns DID_NO_CONNECT error. + + In a second step of the driver development, the following improvement has + been applied: The first approach limited the number of devices to 7, far + fewer than the 15 that it could usem then it just maped ldn -> + (ldn/8,ldn%8) for pun,lun. We ended up with a real mishmash of puns + and luns, but it all seemed to work. + + The latest development, which is implemented from the driver version 3.0 + and later, realizes the device recognition in the following way: + The physical SCSI-devices on the SCSI-bus are probed via immediate_assign- + and device_inquiry-commands, that is all implemented in a completely new + made check_devices() subroutine. This delivers an exact map of the physical + SCSI-world that is now stored in the get_scsi[][]-array. This means, + that the once hidden pun,lun assignment is now known to this driver. + It no longer believes in default-settings of the subsystem and maps all + ldns to existing pun,lun "by foot". This assures full control of the ldn + mapping and allows dynamical remapping of ldns to different pun,lun, if + there are more SCSI-devices installed than ldns available (n>15). The + ldns from 0 to 6 get 'hardwired' by this driver to puns 0 to 7 at lun=0, + excluding the pun of the subsystem. This assures, that at least simple + SCSI-installations have optimum access-speed and are not touched by + dynamical remapping. The ldns 7 to 14 are put to existing devices with + lun>0 or to non-existing devices, in order to satisfy the subsystem, if + there are less than 15 SCSI-devices connected. In the case of more than 15 + devices, the dynamical mapping goes active. If the get_scsi[][] reports a + device to be existant, but it has no ldn assigned, it gets a ldn out of 7 + to 14. The numbers are assigned in cyclic order. Therefore it takes 8 + dynamical reassignments on the SCSI-devices, until a certain device + loses its ldn again. This assures, that dynamical remapping is avoided + during intense I/O between up to 15 SCSI-devices (means pun,lun + combinations). A further advantage of this method is, that people who + build their kernel without probing on all luns will get what they expect, + because the driver just won't assign everything with lun>0 when + multpile lun probing is inactive. + + 2.4 SCSI-Device Order + --------------------- + Because of the now correct recognition of physical pun,lun, and + their report to mid-level- and higher-level-drivers, the new reported puns + can be different from the old, faked puns. Therefore, Linux will eventually + change /dev/sdXXX assignments and prompt you for corrupted superblock + repair on boottime. In this case DO NOT PANIC, YOUR DISKS ARE STILL OK!!! + You have to reboot (CTRL-D) with an old kernel and set the /etc/fstab-file + entries right. After that, the system should come up as errorfree as before. + If your boot-partition is not coming up, also edit the /etc/lilo.conf-file + in a Linux session booted on old kernel and run lilo before reboot. Check + lilo.conf anyway to get boot on other partitions with foreign OSes right + again. But there exists a feature of this driver that allows you to change + the assignment order of the SCSI-devices by flipping the PUN-assignment. + See the next paragraph for a description. + + The problem for this is, that Linux does not assign the SCSI-devices in the + way as described in the ANSI-SCSI-standard. Linux assigns /dev/sda to + the device with at minimum id 0. But the first drive should be at id 6, + because for historical reasons, drive at id 6 has, by hardware, the highest + priority and a drive at id 0 the lowest. IBM was one of the rare producers, + where the BIOS assigns drives belonging to the ANSI-SCSI-standard. Most + other producers' BIOS does not (I think even Adaptec-BIOS). The + IBMMCA_SCSI_ORDER_STANDARD flag, which you set while configuring the + kernel enables to choose the preferred way of SCSI-device-assignment. + Defining this flag would result in Linux determining the devices in the + same order as DOS and OS/2 does on your MCA-machine. This is also standard + on most industrial computers and OSes, like e.g. OS-9. Leaving this flag + undefined will get your devices ordered in the default way of Linux. See + also the remarks of Chris Beauregard from Dec 15, 1997 and the followups + in section 3. + + 2.5 Regular SCSI-Command-Processing + ----------------------------------- + Only three functions get involved: ibmmca_queuecommand(), issue_cmd(), + and interrupt_handler(). + + The upper layer issues a scsi command by calling function + ibmmca_queuecommand(). This function fills a "subsystem control block" + (scb) and calls a local function issue_cmd(), which writes a scb + command into subsystem I/O ports. Once the scb command is carried out, + the interrupt_handler() is invoked. If a device is determined to be + existant and it has not assigned any ldn, it gets one dynamically. + For this, the whole stuff is done in ibmmca_queuecommand(). + + 2.6 Abort & Reset Commands + -------------------------- + These are implemented with busy waiting for interrupt to arrive. + ibmmca_reset() and ibmmca_abort() do not work sufficently well + up to now and need still a lot of development work. But, this seems + to be even a problem with other SCSI-low level drivers, too. However, + this should be no excuse. + + 2.7 Disk Geometry + ----------------- + The ibmmca_biosparams() function should return the same disk geometry + as the bios. This is needed for fdisk, etc. The returned geometry is + certainly correct for disks smaller than 1 gigabyte. In the meantime, + it has been proved, that this works fine even with disks larger than + 1 gigabyte. + + 2.8 Kernel Boot Option + ---------------------- + The function ibmmca_scsi_setup() is called if option ibmmcascsi=n + is passed to the kernel. See file linux/init/main.c for details. + + 2.9 Driver Module Support + ------------------------- + Is implemented and tested by K. Kudielka. This could probably not work + on kernels <2.1.0. + + 2.10 Multiple Hostadapter Support + --------------------------------- + This driver supports up to eight interfaces of type IBM-SCSI-Subsystem. + Integrated-, and MCA-adapters are automatically recognized. Unrecognizable + IBM-SCSI-Subsystem interfaces can be specified as kernel-parameters. + + 2.11 /proc/scsi-Filesystem Information + -------------------------------------- + Information about the driver condition is given in + /proc/scsi/ibmmca/<host_no>. ibmmca_proc_info() provides this information. + + This table is quite informative for interested users. It shows the load + of commands on the subsystem and wether you are running the bypassed + (software) or integrated (hardware) SCSI-command set (see below). The + amount of accesses is shown. Read, write, modeselect is shown separately + in order to help debugging problems with CD-ROMs or tapedrives. + + The following table shows the list of 15 logical device numbers, that are + used by the SCSI-subsystem. The load on each ldn is shown in the table, + again, read and write commands are split. The last column shows the amount + of reassignments, that have been applied to the ldns, if you have more than + 15 pun/lun combinations available on the SCSI-bus. + + The last two tables show the pun/lun map and the positions of the ldns + on this pun/lun map. This may change during operation, when a ldn is + reassigned to another pun/lun combination. If the necessity for dynamical + assignments is set to 'no', the ldn structure keeps static. + + 2.12 /proc/mca-Filesystem Information + ------------------------------------- + The slot-file contains all default entries and in addition chip and I/O- + address information of the SCSI-subsystem. This information is provided + by ibmmca_getinfo(). + + 2.13 Supported IBM SCSI-Subsystems + ---------------------------------- + The following IBM SCSI-subsystems are supported by this driver: + + - IBM Fast/Wide SCSI-2 Adapter + - IBM 7568 Industrial Computer SCSI Adapter w/Cache + - IBM Expansion Unit SCSI Controller + - IBM SCSI Adapter w/Cache + - IBM SCSI Adapter + - IBM Integrated SCSI Controller + - All clones, 100% compatible with the chipset and subsystem command + system of IBM SCSI-adapters (forced detection) + + 2.14 Linux Kernel Versions + -------------------------- + The IBM SCSI-subsystem low level driver is prepared to be used with + all versions of Linux between 2.0.x and 2.4.x. The compatibility checks + are fully implemented up from version 3.1e of the driver. This means, that + you just need the latest ibmmca.h and ibmmca.c file and copy it in the + linux/drivers/scsi directory. The code is automatically adapted during + kernel compilation. This is different from kernel 2.4.0! Here version + 4.0 or later of the driver must be used for kernel 2.4.0 or later. Version + 4.0 or later does not work together with older kernels! Driver versions + older than 4.0 do not work together with kernel 2.4.0 or later. They work + on all older kernels. + + 3 Code History + -------------- + Jan 15 1996: First public release. + - Martin Kolinek + + Jan 23 1996: Scrapped code which reassigned scsi devices to logical + device numbers. Instead, the existing assignment (created + when the machine is powered-up or rebooted) is used. + A side effect is that the upper layer of Linux SCSI + device driver gets bogus scsi ids (this is benign), + and also the hard disks are ordered under Linux the + same way as they are under dos (i.e., C: disk is sda, + D: disk is sdb, etc.). + - Martin Kolinek + + I think that the CD-ROM is now detected only if a CD is + inside CD_ROM while Linux boots. This can be fixed later, + once the driver works on all types of PS/2's. + - Martin Kolinek + + Feb 7 1996: Modified biosparam function. Fixed the CD-ROM detection. + For now, devices other than harddisk and CD_ROM are + ignored. Temporarily modified abort() function + to behave like reset(). + - Martin Kolinek + + Mar 31 1996: The integrated scsi subsystem is correctly found + in PS/2 models 56,57, but not in model 76. Therefore + the ibmmca_scsi_setup() function has been added today. + This function allows the user to force detection of + scsi subsystem. The kernel option has format + ibmmcascsi=n + where n is the scsi_id (pun) of the subsystem. Most likely, n is 7. + - Martin Kolinek + + Aug 21 1996: Modified the code which maps ldns to (pun,0). It was + insufficient for those of us with CD-ROM changers. + - Chris Beauregard + + Dec 14 1996: More improvements to the ldn mapping. See check_devices + for details. Did more fiddling with the integrated SCSI detection, + but I think it's ultimately hopeless without actually testing the + model of the machine. The 56, 57, 76 and 95 (ultimedia) all have + different integrated SCSI register configurations. However, the 56 + and 57 are the only ones that have problems with forced detection. + - Chris Beauregard + + Mar 8-16 1997: Modified driver to run as a module and to support + multiple adapters. A structure, called ibmmca_hostdata, is now + present, containing all the variables, that were once only + available for one single adapter. The find_subsystem-routine has vanished. + The hardware recognition is now done in ibmmca_detect directly. + This routine checks for presence of MCA-bus, checks the interrupt + level and continues with checking the installed hardware. + Certain PS/2-models do not recognize a SCSI-subsystem automatically. + Hence, the setup defined by command-line-parameters is checked first. + Thereafter, the routine probes for an integrated SCSI-subsystem. + Finally, adapters are checked. This method has the advantage to cover all + possible combinations of multiple SCSI-subsystems on one MCA-board. Up to + eight SCSI-subsystems can be recognized and announced to the upper-level + drivers with this improvement. A set of defines made changes to other + routines as small as possible. + - Klaus Kudielka + + May 30 1997: (v1.5b) + 1) SCSI-command capability enlarged by the recognition of MODE_SELECT. + This needs the RD-Bit to be disabled on IM_OTHER_SCSI_CMD_CMD which + allows data to be written from the system to the device. It is a + necessary step to be allowed to set blocksize of SCSI-tape-drives and + the tape-speed, whithout confusing the SCSI-Subsystem. + 2) The recognition of a tape is included in the check_devices routine. + This is done by checking for TYPE_TAPE, that is already defined in + the kernel-scsi-environment. The markup of a tape is done in the + global ldn_is_tape[] array. If the entry on index ldn + is 1, there is a tapedrive connected. + 3) The ldn_is_tape[] array is necessary to distinguish between tape- and + other devices. Fixed blocklength devices should not cause a problem + with the SCB-command for read and write in the ibmmca_queuecommand + subroutine. Therefore, I only derivate the READ_XX, WRITE_XX for + the tape-devices, as recommended by IBM in this Technical Reference, + mentioned below. (IBM recommends to avoid using the read/write of the + subsystem, but the fact was, that read/write causes a command error from + the subsystem and this causes kernel-panic.) + 4) In addition, I propose to use the ldn instead of a fix char for the + display of PS2_DISK_LED_ON(). On 95, one can distinguish between the + devices that are accessed. It shows activity and easyfies debugging. + The tape-support has been tested with a SONY SDT-5200 and a HP DDS-2 + (I do not know yet the type). Optimization and CD-ROM audio-support, + I am working on ... + - Michael Lang + + June 19 1997: (v1.6b) + 1) Submitting the extra-array ldn_is_tape[] -> to the local ld[] + device-array. + 2) CD-ROM Audio-Play seems to work now. + 3) When using DDS-2 (120M) DAT-Tapes, mtst shows still density-code + 0x13 for ordinary DDS (61000 BPM) instead 0x24 for DDS-2. This appears + also on Adaptec 2940 adaptor in a PCI-System. Therefore, I assume that + the problem is independent of the low-level-driver/bus-architecture. + 4) Hexadecimal ldn on PS/2-95 LED-display. + 5) Fixing of the PS/2-LED on/off that it works right with tapedrives and + does not confuse the disk_rw_in_progress counter. + - Michael Lang + + June 21 1997: (v1.7b) + 1) Adding of a proc_info routine to inform in /proc/scsi/ibmmca/<host> the + outer-world about operational load statistics on the different ldns, + seen by the driver. Everybody that has more than one IBM-SCSI should + test this, because I only have one and cannot see what happens with more + than one IBM-SCSI hosts. + 2) Definition of a driver version-number to have a better recognition of + the source when there are existing too much releases that may confuse + the user, when reading about release-specific problems. Up to know, + I calculated the version-number to be 1.7. Because we are in BETA-test + yet, it is today 1.7b. + 3) Sorry for the heavy bug I programmed on June 19 1997! After that, the + CD-ROM did not work any more! The C7-command was a fake impression + I got while programming. Now, the READ and WRITE commands for CD-ROM are + no longer running over the subsystem, but just over + IM_OTHER_SCSI_CMD_CMD. On my observations (PS/2-95), now CD-ROM mounts + much faster(!) and hopefully all fancy multimedia-functions, like direct + digital recording from audio-CDs also work. (I tried it with cdda2wav + from the cdwtools-package and it filled up the harddisk immediately :-).) + To easify boolean logics, a further local device-type in ld[], called + is_cdrom has been included. + 4) If one uses a SCSI-device of unsupported type/commands, one + immediately runs into a kernel-panic caused by Command Error. To better + understand which SCSI-command caused the problem, I extended this + specific panic-message slightly. + - Michael Lang + + June 25 1997: (v1.8b) + 1) Some cosmetical changes for the handling of SCSI-device-types. + Now, also CD-Burners / WORMs and SCSI-scanners should work. For + MO-drives I have no experience, therefore not yet supported. + In logical_devices I changed from different type-variables to one + called 'device_type' where the values, corresponding to scsi.h, + of a SCSI-device are stored. + 2) There existed a small bug, that maps a device, coming after a SCSI-tape + wrong. Therefore, e.g. a CD-ROM changer would have been mapped wrong + -> problem removed. + 3) Extension of the logical_device structure. Now it contains also device, + vendor and revision-level of a SCSI-device for internal usage. + - Michael Lang + + June 26-29 1997: (v2.0b) + 1) The release number 2.0b is necessary because of the completely new done + recognition and handling of SCSI-devices with the adapter. As I got + from Chris the hint, that the subsystem can reassign ldns dynamically, + I remembered this immediate_assign-command, I found once in the handbook. + Now, the driver first kills all ldn assignments that are set by default + on the SCSI-subsystem. After that, it probes on all puns and luns for + devices by going through all combinations with immediate_assign and + probing for devices, using device_inquiry. The found physical(!) pun,lun + structure is stored in get_scsi[][] as device types. This is followed + by the assignment of all ldns to existing SCSI-devices. If more ldns + than devices are available, they are assigned to non existing pun,lun + combinations to satisfy the adapter. With this, the dynamical mapping + was possible to implement. (For further info see the text in the + source-code and in the description below. Read the description + below BEFORE installing this driver on your system!) + 2) Changed the name IBMMCA_DRIVER_VERSION to IBMMCA_SCSI_DRIVER_VERSION. + 3) The LED-display shows on PS/2-95 no longer the ldn, but the SCSI-ID + (pun) of the accessed SCSI-device. This is now senseful, because the + pun known within the driver is exactly the pun of the physical device + and no longer a fake one. + 4) The /proc/scsi/ibmmca/<host_no> consists now of the first part, where + hit-statistics of ldns is shown and a second part, where the maps of + physical and logical SCSI-devices are displayed. This could be very + interesting, when one is using more than 15 SCSI-devices in order to + follow the dynamical remapping of ldns. + - Michael Lang + + June 26-29 1997: (v2.0b-1) + 1) I forgot to switch the local_checking_phase_flag to 1 and back to 0 + in the dynamical remapping part in ibmmca_queuecommand for the + device_exist routine. Sorry. + - Michael Lang + + July 1-13 1997: (v3.0b,c) + 1) Merging of the driver-developments of Klaus Kudielka and Michael Lang + in order to get a optimum and unified driver-release for the + IBM-SCSI-Subsystem-Adapter(s). + For people, using the Kernel-release >=2.1.0, module-support should + be no problem. For users, running under <2.1.0, module-support may not + work, because the methods have changed between 2.0.x and 2.1.x. + 2) Added some more effective statistics for /proc-output. + 3) Change typecasting at necessary points from (unsigned long) to + virt_to_bus(). + 4) Included #if... at special points to have specific adaption of the + driver to kernel 2.0.x and 2.1.x. It should therefore also run with + later releases. + 5) Magneto-Optical drives and medium-changers are also recognized, now. + Therefore, we have a completely gapfree recognition of all SCSI- + device-types, that are known by Linux up to kernel 2.1.31. + 6) The flag SCSI_IBMMCA_DEV_RESET has been inserted. If it is set within + the configuration, each connected SCSI-device will get a reset command + during boottime. This can be necessary for some special SCSI-devices. + This flag should be included in Config.in. + (See also the new Config.in file.) + Probable next improvement: bad disk handler. + - Michael Lang + + Sept 14 1997: (v3.0c) + 1) Some debugging and speed optimization applied. + - Michael Lang + + Dec 15, 1997 + - chrisb@truespectra.com + - made the front panel display thingy optional, specified from the + command-line via ibmmcascsi=display. Along the lines of the /LED + option for the OS/2 driver. + - fixed small bug in the LED display that would hang some machines. + - reversed ordering of the drives (using the + IBMMCA_SCSI_ORDER_STANDARD define). This is necessary for two main + reasons: + - users who've already installed Linux won't be screwed. Keep + in mind that not everyone is a kernel hacker. + - be consistent with the BIOS ordering of the drives. In the + BIOS, id 6 is C:, id 0 might be D:. With this scheme, they'd be + backwards. This confuses the crap out of those heathens who've + got a impure Linux installation (which, <wince>, I'm one of). + This whole problem arises because IBM is actually non-standard with + the id to BIOS mappings. You'll find, in fdomain.c, a similar + comment about a few FD BIOS revisions. The Linux (and apparently + industry) standard is that C: maps to scsi id (0,0). Let's stick + with that standard. + - Since this is technically a branch of my own, I changed the + version number to 3.0e-cpb. + + Jan 17, 1998: (v3.0f) + 1) Addition of some statistical info for /proc in proc_info. + 2) Taking care of the SCSI-assignment problem, dealed by Chris at Dec 15 + 1997. In fact, IBM is right, concerning the assignment of SCSI-devices + to driveletters. It is conform to the ANSI-definition of the SCSI- + standard to assign drive C: to SCSI-id 6, because it is the highest + hardware priority after the hostadapter (that has still today by + default everywhere id 7). Also realtime-operating systems that I use, + like LynxOS and OS9, which are quite industrial systems use top-down + numbering of the harddisks, that is also starting at id 6. Now, one + sits a bit between two chairs. On one hand side, using the define + IBMMCA_SCSI_ORDER_STANDARD makes Linux assigning disks conform to + the IBM- and ANSI-SCSI-standard and keeps this driver downward + compatible to older releases, on the other hand side, people is quite + habituated in believing that C: is assigned to (0,0) and much other + SCSI-BIOS do so. Therefore, I moved the IBMMCA_SCSI_ORDER_STANDARD + define out of the driver and put it into Config.in as subitem of + 'IBM SCSI support'. A help, added to Documentation/Configure.help + explains the differences between saying 'y' or 'n' to the user, when + IBMMCA_SCSI_ORDER_STANDARD prompts, so the ordinary user is enabled to + choose the way of assignment, depending on his own situation and gusto. + 3) Adapted SCSI_IBMMCA_DEV_RESET to the local naming convention, so it is + now called IBMMCA_SCSI_DEV_RESET. + 4) Optimization of proc_info and its subroutines. + 5) Added more in-source-comments and extended the driver description by + some explanation about the SCSI-device-assignment problem. + - Michael Lang + + Jan 18, 1998: (v3.0g) + 1) Correcting names to be absolutely conform to the later 2.1.x releases. + This is necessary for + IBMMCA_SCSI_DEV_RESET -> CONFIG_IBMMCA_SCSI_DEV_RESET + IBMMCA_SCSI_ORDER_STANDARD -> CONFIG_IBMMCA_SCSI_ORDER_STANDARD + - Michael Lang + + Jan 18, 1999: (v3.1 MCA-team internal) + 1) The multiple hosts structure is accessed from every subroutine, so there + is no longer the address of the device structure passed from function + to function, but only the hostindex. A call by value, nothing more. This + should really be understood by the compiler and the subsystem should get + the right values and addresses. + 2) The SCSI-subsystem detection was not complete and quite hugely buggy up + to now, compared to the technical manual. The interpretation of the pos2 + register is not as assumed by people before, therefore, I dropped a note + in the ibmmca_detect function to show the registers' interpretation. + The pos-registers of integrated SCSI-subsystems do not contain any + information concerning the IO-port offset, really. Instead, they contain + some info about the adapter, the chip, the NVRAM .... The I/O-port is + fixed to 0x3540 - 0x3547. There can be more than one adapters in the + slots and they get an offset for the I/O area in order to get their own + I/O-address area. See chapter 2 for detailed description. At least, the + detection should now work right, even on models other than 95. The 95ers + came happily around the bug, as their pos2 register contains always 0 + in the critical area. Reserved bits are not allowed to be interpreted, + therefore, IBM is allowed to set those bits as they like and they may + really vary between different PS/2 models. So, now, no interpretation + of reserved bits - hopefully no trouble here anymore. + 3) The command error, which you may get on models 55, 56, 57, 70, 77 and + P70 may have been caused by the fact, that adapters of older design do + not like sending commands to non-existing SCSI-devices and will react + with a command error as a sign of protest. While this error is not + present on IBM SCSI Adapter w/cache, it appears on IBM Integrated SCSI + Adapters. Therefore, I implemented a workarround to forgive those + adapters their protests, but it is marked up in the statisctis, so + after a successful boot, you can see in /proc/scsi/ibmmca/<host_number> + how often the command errors have been forgiven to the SCSI-subsystem. + If the number is bigger than 0, you have a SCSI subsystem of older + design, what should no longer matter. + 4) ibmmca_getinfo() has been adapted very carefully, so it shows in the + slotn file really, what is senseful to be presented. + 5) ibmmca_register() has been extended in its parameter list in order to + pass the right name of the SCSI-adapter to Linux. + - Michael Lang + + Feb 6, 1999: (v3.1) + 1) Finally, after some 3.1Beta-releases, the 3.1 release. Sorry, for + the delayed release, but it was not finished with the release of + Kernel 2.2.0. + - Michael Lang + + Feb 10, 1999 (v3.1) + 1) Added a new commandline parameter called 'bypass' in order to bypass + every integrated subsystem SCSI-command consequently in case of + troubles. + 2) Concatenated read_capacity requests to the harddisks. It gave a lot + of troubles with some controllers and after I wanted to apply some + extensions, it jumped out in the same situation, on my w/cache, as like + on D. Weinehalls' Model 56, having integrated SCSI. This gave me the + descissive hint to move the code-part out and declare it global. Now, + it seems to work by far much better an more stable. Let us see, what + the world thinks of it... + 3) By the way, only Sony DAT-drives seem to show density code 0x13. A + test with a HP drive gave right results, so the problem is vendor- + specific and not a problem of the OS or the driver. + - Michael Lang + + Feb 18, 1999 (v3.1d) + 1) The abort command and the reset function have been checked for + inconsistencies. From the logical point of thinking, they work + at their optimum, now, but as the subsystem does not answer with an + interrupt, abort never finishes, sigh... + 2) Everything, that is accessed by a busmaster request from the adapter + is now declared as global variable, even the return-buffer in the + local checking phase. This assures, that no accesses to undefined memory + areas are performed. + 3) In ibmmca.h, the line unchecked_isa_dma is added with 1 in order to + avoid memory-pointers for the areas higher than 16MByte in order to + be sure, it also works on 16-Bit Microchannel bus systems. + 4) A lot of small things have been found, but nothing that endangered the + driver operations. Just it should be more stable, now. + - Michael Lang + + Feb 20, 1999 (v3.1e) + 1) I took the warning from the Linux Kernel Hackers Guide serious and + checked the cmd->result return value to the done-function very carefully. + It is obvious, that the IBM SCSI only delivers the tsb.dev_status, if + some error appeared, else it is undefined. Now, this is fixed. Before + any SCB command gets queued, the tsb.dev_status is set to 0, so the + cmd->result won't screw up Linux higher level drivers. + 2) The reset-function has slightly improved. This is still planed for + abort. During the abort and the reset function, no interrupts are + allowed. This is however quite hard to cope with, so the INT-status + register is read. When the interrupt gets queued, one can find its + status immediately on that register and is enabled to continue in the + reset function. I had no chance to test this really, only in a bogus + situation, I got this function running, but the situation was too much + worse for Linux :-(, so tests will continue. + 3) Buffers got now consistent. No open address mapping, as before and + therefore no further troubles with the unassigned memory segmentation + faults that scrambled probes on 95XX series and even on 85XX series, + when the kernel is done in a not so perfectly fitting way. + 4) Spontaneous interrupts from the subsystem, appearing without any + command previously queued are answered with a DID_BAD_INTR result. + 5) Taken into account ZP Gus' proposals to reverse the SCSI-device + scan order. As it does not work on Kernel 2.1.x or 2.2.x, as proposed + by him, I implemented it in a slightly derived way, which offers in + addition more flexibility. + - Michael Lang + + Apr 23, 2000 (v3.2pre1) + 1) During a very long time, I collected a huge amount of bugreports from + various people, trying really quite different things on their SCSI- + PS/2s. Today, all these bugreports are taken into account and should be + mostly solved. The major topics were: + - Driver crashes during boottime by no obvious reason. + - Driver panics while the midlevel-SCSI-driver is trying to inquire + the SCSI-device properties, even though hardware is in perfect state. + - Displayed info for the various slot-cards is interpreted wrong. + The main reasons for the crashes were two: + 1) The commands to check for device information like INQUIRY, + TEST_UNIT_READY, REQUEST_SENSE and MODE_SENSE cause the devices + to deliver information of up to 255 bytes. Midlevel drivers offer + 1024 bytes of space for the answer, but the IBM-SCSI-adapters do + not accept this, as they stick quite near to ANSI-SCSI and report + a COMMAND_ERROR message which causes the driver to panic. The main + problem was located around the INQUIRY command. Now, for all the + mentioned commands, the buffersize, sent to the adapter is at + maximum 255 which seems to be a quite reasonable solution. + TEST_UNIT_READY gets a buffersize of 0 to make sure, that no + data is transferred in order to avoid any possible command failure. + 2) On unsuccessful TEST_UNIT_READY, the midlevel-driver has to send + a REQUEST_SENSE in order to see, where the problem is located. This + REQUEST_SENSE may have various length in its answer-buffer. IBM + SCSI-subsystems report a command failure, if the returned buffersize + is different from the sent buffersize, but this can be supressed by + a special bit, which is now done and problems seem to be solved. + 2) Code adaption to all kernel-releases. Now, the 3.2 code compiles on + 2.0.x, 2.1.x, 2.2.x and 2.3.x kernel releases without any code-changes. + 3) Commandline-parameters are recognized again, even under Kernel 2.3.x or + higher. + - Michael Lang + + April 27, 2000 (v3.2pre2) + 1) Bypassed commands get read by the adapter by one cycle instead of two. + This increases SCSI-performance. + 2) Synchronous datatransfer is provided for sure to be 5 MHz on older + SCSI and 10 MHz on internal F/W SCSI-adapter. + 3) New commandline parameters allow to force the adapter to slow down while + in synchronous transfer. Could be helpful for very old devices. + - Michael Lang + + June 2, 2000 (v3.2pre5) + 1) Added Jim Shorney's contribution to make the activity indicator + flashing in addition to the LED-alphanumeric display-panel on + models 95A. To be enabled to choose this feature freely, a new + commandline parameter is added, called 'activity'. + 2) Added the READ_CONTROL bit for test_unit_ready SCSI-command. + 3) Added some suppress_exception bits to read_device_capacity and + all device_inquiry occurrences in the driver code. + 4) Complaints about the various KERNEL_VERSION implementations are + taken into account. Every local_LinuxKernelVersion occurrence is + now replaced by KERNEL_VERSION, defined in linux/version.h. + Corresponding changes were applied to ibmmca.h, too. This was a + contribution to all kernel-parts by Philipp Hahn. + - Michael Lang + + July 17, 2000 (v3.2pre8) + A long period of collecting bugreports from all corners of the world + now lead to the following corrections to the code: + 1) SCSI-2 F/W support crashed with a COMMAND ERROR. The reason for this + was, that it is possible to disbale Fast-SCSI for the external bus. + The feature-control command, where this crash appeared regularly tried + to set the maximum speed of 10MHz synchronous transfer speed and that + reports a COMMAND ERROR, if external bus Fast-SCSI is disabled. Now, + the feature-command probes down from maximum speed until the adapter + stops to complain, which is at the same time the maximum possible + speed selected in the reference program. So, F/W external can run at + 5 MHz (slow-) or 10 MHz (fast-SCSI). During feature probing, the + COMMAND ERROR message is used to detect if the adapter does not complain. + 2) Up to now, only combined busmode is supported, if you use external + SCSI-devices, attached to the F/W-controller. If dual bus is selected, + only the internal SCSI-devices get accessed by Linux. For most + applications, this should do fine. + 3) Wide-SCSI-addressing (16-Bit) is now possible for the internal F/W + bus on the F/W adapter. If F/W adapter is detected, the driver + automatically uses the extended PUN/LUN <-> LDN mapping tables, which + are now new from 3.2pre8. This allows PUNs between 0 and 15 and should + provide more fun with the F/W adapter. + 4) Several machines use the SCSI: POS registers for internal/undocumented + storage of system relevant info. This confused the driver, mainly on + models 9595, as it expected no onboard SCSI only, if all POS in + the integrated SCSI-area are set to 0x00 or 0xff. Now, the mechanism + to check for integrated SCSI is much more restrictive and these problems + should be history. + - Michael Lang + + July 18, 2000 (v3.2pre9) + This develop rather quickly at the moment. Two major things were still + missing in 3.2pre8: + 1) The adapter PUN for F/W adapters has 4-bits, while all other adapters + have 3-bits. This is now taken into account for F/W. + 2) When you select CONFIG_IBMMCA_SCSI_ORDER_STANDARD, you should + normally get the inverse probing order of your devices on the SCSI-bus. + The ANSI device order gets scrambled in version 3.2pre8!! Now, a new + and tested algorithm inverts the device-order on the SCSI-bus and + automatically avoids accidental access to whatever SCSI PUN the adapter + is set and works with SCSI- and Wide-SCSI-addressing. + - Michael Lang + + July 23, 2000 (v3.2pre10 unpublished) + 1) LED panel display supports wide-addressing in ibmmca=display mode. + 2) Adapter-information and autoadaption to address-space is done. + 3) Auto-probing for maximum synchronous SCSI transfer rate is working. + 4) Optimization to some embedded function calls is applied. + 5) Added some comment for the user to wait for SCSI-devices being probed. + 6) Finished version 3.2 for Kernel 2.4.0. It least, I thought it is but... + - Michael Lang + + July 26, 2000 (v3.2pre11) + 1) I passed a horrible weekend getting mad with NMIs on kernel 2.2.14 and + a model 9595. Asking around in the community, nobody except of me has + seen such errors. Weired, but I am trying to recompile everything on + the model 9595. Maybe, as I use a specially modified gcc, that could + cause problems. But, it was not the reason. The true background was, + that the kernel was compiled for i386 and the 9595 has a 486DX-2. + Normally, no troubles should appear, but for this special machine, + only the right processor support is working fine! + 2) Previous problems with synchronous speed, slowing down from one adapter + to the next during probing are corrected. Now, local variables store + the synchronous bitmask for every single adapter found on the MCA bus. + 3) LED alphanumeric panel support for XX95 systems is now showing some + alive rotator during boottime. This makes sense, when no monitor is + connected to the system. You can get rid of all display activity, if + you do not use any parameter or just ibmmcascsi=activity, for the + harddrive activity LED, existant on all PS/2, except models 8595-XXX. + If no monitor is available, please use ibmmcascsi=display, which works + fine together with the linuxinfo utility for the LED-panel. + - Michael Lang + + July 29, 2000 (v3.2) + 1) Submission of this driver for kernel 2.4test-XX and 2.2.17. + - Michael Lang + + December 28, 2000 (v3.2d / v4.0) + 1) The interrupt handler had some wrong statement to wait for. This + was done due to experimental reasons during 3.2 development but it + has shown that this is not stable enough. Going back to wait for the + adapter to be not busy is best. + 2) Inquiry requests can be shorter than 255 bytes of return buffer. Due + to a bug in the ibmmca_queuecommand routine, this buffer was forced + to 255 at minimum. If the memory address, this return buffer is pointing + to does not offer more space, invalid memory accesses destabilized the + kernel. + 3) version 4.0 is only valid for kernel 2.4.0 or later. This is necessary + to remove old kernel version dependent waste from the driver. 3.2d is + only distributed with older kernels but keeps compatibility with older + kernel versions. 4.0 and higher versions cannot be used with older + kernels anymore!! You must have at least kernel 2.4.0!! + 4) The commandline argument 'bypass' and all its functionality got removed + in version 4.0. This was never really necessary, as all troubles were + based on non-command related reasons up to now, so bypassing commands + did not help to avoid any bugs. It is kept in 3.2X for debugging reasons. + 5) Dynamical reassignment of ldns was again verified and analyzed to be + completely inoperational. This is corrected and should work now. + 6) All commands that get sent to the SCSI adapter were verified and + completed in such a way, that they are now completely conform to the + demands in the technical description of IBM. Main candidates were the + DEVICE_INQUIRY, REQUEST_SENSE and DEVICE_CAPACITY commands. They must + be tranferred by bypassing the internal command buffer of the adapter + or else the response can be a random result. GET_POS_INFO would be more + safe in usage, if one could use the SUPRESS_EXCEPTION_SHORT, but this + is not allowed by the technical references of IBM. (Sorry, folks, the + model 80 problem is still a task to be solved in a different way.) + 7) v3.2d is still hold back for some days for testing, while 4.0 is + released. + - Michael Lang + + January 3, 2001 (v4.0a) + 1) A lot of complains after the 2.4.0-prerelease kernel came in about + the impossibility to compile the driver as a module. This problem is + solved. In combination with that problem, some unprecise declaration + of the function option_setup() gave some warnings during compilation. + This is solved, too by a forward declaration in ibmmca.c. + 2) #ifdef argument concerning CONFIG_SCSI_IBMMCA is no longer needed and + was entirely removed. + 3) Some switch statements got optimized in code, as some minor variables + in internal SCSI-command handlers. + - Michael Lang + + 4 To do + ------- + - IBM SCSI-2 F/W external SCSI bus support in separate mode! + - It seems that the handling of bad disks is really bad - + non-existent, in fact. However, a low-level driver cannot help + much, if such things happen. + + 5 Users' Manual + --------------- + 5.1 Commandline Parameters + -------------------------- + There exist several features for the IBM SCSI-subsystem driver. + The commandline parameter format is: + + ibmmcascsi=<command1>,<command2>,<command3>,... + + where commandN can be one of the following: + + display Owners of a model 95 or other PS/2 systems with an + alphanumeric LED display may set this to have their + display showing the following output of the 8 digits: + + ------DA + + where '-' stays dark, 'D' shows the SCSI-device id + and 'A' shows the SCSI hostindex, being currently + accessed. During boottime, this will give the message + + SCSIini* + + on the LED-panel, where the * represents a rotator, + showing the activity during the probing phase of the + driver which can take up to two minutes per SCSI-adapter. + adisplay This works like display, but gives more optical overview + of the activities on the SCSI-bus. The display will have + the following output: + + 6543210A + + where the numbers 0 to 6 light up at the shown position, + when the SCSI-device is accessed. 'A' shows again the SCSI + hostindex. If display nor adisplay is set, the internal + PS/2 harddisk LED is used for media-activities. So, if + you really do not have a system with a LED-display, you + should not set display or adisplay. Keep in mind, that + display and adisplay can only be used alternatively. It + is not recommended to use this option, if you have some + wide-addressed devices e.g. at the SCSI-2 F/W adapter in + your system. In addition, the usage of the display for + other tasks in parallel, like the linuxinfo-utility makes + no sense with this option. + activity This enables the PS/2 harddisk LED activity indicator. + Most PS/2 have no alphanumeric LED display, but some + indicator. So you should use this parameter to activate it. + If you own model 9595 (Server95), you can have both, the + LED panel and the activity indicator in parallel. However, + some PS/2s, like the 8595 do not have any harddisk LED + activity indicator, which means, that you must use the + alphanumeric LED display if you want to monitor SCSI- + activity. + bypass This is obsolete from driver version 4.0, as the adapters + got that far understood, that the selection between + integrated and bypassed commands should now work completely + correct! For historical reasons, the old description is + kept here: + This commandline parameter forces the driver never to use + SCSI-subsystems' integrated SCSI-command set. Except of + the immediate assign, which is of vital importance for + every IBM SCSI-subsystem to set its ldns right. Instead, + the ordinary ANSI-SCSI-commands are used and passed by the + controller to the SCSI-devices, therefore 'bypass'. The + effort, done by the subsystem is quite bogus and at a + minimum and therefore it should work everywhere. This + could maybe solve troubles with old or integrated SCSI- + controllers and nasty harddisks. Keep in mind, that using + this flag will slow-down SCSI-accesses slightly, as the + software generated commands are always slower than the + hardware. Non-harddisk devices always get read/write- + commands in bypass mode. On the most recent releases of + the Linux IBM-SCSI-driver, the bypass command should be + no longer a necessary thing, if you are sure about your + SCSI-hardware! + normal This is the parameter, introduced on the 2.0.x development + rail by ZP Gu. This parameter defines the SCSI-device + scan order in the new industry standard. This means, that + the first SCSI-device is the one with the lowest pun. + E.g. harddisk at pun=0 is scanned before harddisk at + pun=6, which means, that harddisk at pun=0 gets sda + and the one at pun=6 gets sdb. + ansi The ANSI-standard for the right scan order, as done by + IBM, Microware and Microsoft, scans SCSI-devices starting + at the highest pun, which means, that e.g. harddisk at + pun=6 gets sda and a harddisk at pun=0 gets sdb. If you + like to have the same SCSI-device order, as in DOS, OS-9 + or OS/2, just use this parameter. + fast SCSI-I/O in synchronous mode is done at 5 MHz for IBM- + SCSI-devices. SCSI-2 Fast/Wide Adapter/A external bus + should then run at 10 MHz if Fast-SCSI is enabled, + and at 5 MHz if Fast-SCSI is disabled on the external + bus. This is the default setting when nothing is + specified here. + medium Synchronous rate is at 50% approximately, which means + 2.5 MHz for IBM SCSI-adapters and 5.0 MHz for F/W ext. + SCSI-bus (when Fast-SCSI speed enabled on external bus). + slow The slowest possible synchronous transfer rate is set. + This means 1.82 MHz for IBM SCSI-adapters and 2.0 MHz + for F/W external bus at Fast-SCSI speed on the external + bus. + + A further option is that you can force the SCSI-driver to accept a SCSI- + subsystem at a certain I/O-address with a predefined adapter PUN. This + is done by entering + + commandN = I/O-base + commandN+1 = adapter PUN + + e.g. ibmmcascsi=0x3540,7 will force the driver to detect a SCSI-subsystem + at I/O-address 0x3540 with adapter PUN 7. Please only use this method, if + the driver does really not recognize your SCSI-adapter! With driver version + 3.2, this recognition of various adapters was hugely improved and you + should try first to remove your commandline arguments of such type with a + newer driver. I bet, it will be recognized correctly. Even multiple and + different types of IBM SCSI-adapters should be recognized correctly, too. + Use the forced detection method only as last solution! + + Examples: + + ibmmcascsi=adisplay + + This will use the advanced display mode for the model 95 LED alphanumeric + display. + + ibmmcascsi=display,0x3558,7 + + This will activate the default display mode for the model 95 LED display + and will force the driver to accept a SCSI-subsystem at I/O-base 0x3558 + with adapter PUN 7. + + 5.2 Troubleshooting + ------------------- + The following FAQs should help you to solve some major problems with this + driver. + + Q: "Reset SCSI-devices at boottime" halts the system at boottime, why? + A: This is only tested with the IBM SCSI Adapter w/cache. It is not + yet prooved to run on other adapters, however you may be lucky. + In version 3.1d this has been hugely improved and should work better, + now. Normally you really won't need to activate this flag in the + kernel configuration, as all post 1989 SCSI-devices should accept + the reset-signal, when the computer is switched on. The SCSI- + subsystem generates this reset while being initialized. This flag + is really reserved for users with very old, very strange or self-made + SCSI-devices. + Q: Why is the SCSI-order of my drives mirrored to the device-order + seen from OS/2 or DOS ? + A: It depends on the operating system, if it looks at the devices in + ANSI-SCSI-standard (starting from pun 6 and going down to pun 0) or + if it just starts at pun 0 and counts up. If you want to be conform + with OS/2 and DOS, you have to activate this flag in the kernel + configuration or you should set 'ansi' as parameter for the kernel. + The parameter 'normal' sets the new industry standard, starting + from pun 0, scanning up to pun 6. This allows you to change your + opinion still after having already compiled the kernel. + Q: Why I cannot find the IBM MCA SCSI support in the config menue? + A: You have to activate MCA bus support, first. + Q: Where can I find the latest info about this driver? + A: See the file MAINTAINERS for the current WWW-address, which offers + updates, info and Q/A lists. At this files' origin, the webaddress + was: http://www.uni-mainz.de/~langm000/linux.html + Q: My SCSI-adapter is not recognized by the driver, what can I do? + A: Just force it to be recognized by kernel parameters. See section 5.1. + If this really happens, do also send e-mail to the maintainer, as + forced detection should be never necessary. Forced detection is in + principal some flaw of the driver adapter detection and goes into + bugreports. + Q: The driver screws up, if it starts to probe SCSI-devices, is there + some way out of it? + A: Yes, that was some recognition problem of the correct SCSI-adapter + and its I/O base addresses. Upgrade your driver to the latest release + and it should be fine again. + Q: I get a message: panic IBM MCA SCSI: command error .... , what can + I do against this? + A: Previously, I followed the way by ignoring command errors by using + ibmmcascsi=forgiveall, but this command no longer exists and is + obsolete. If such a problem appears, it is caused by some segmentation + fault of the driver, which maps to some unallowed area. The latest + version of the driver should be ok, as most bugs have been solved. + Q: There are still kernel panics, even after having set + ibmmcascsi=forgiveall. Are there other possibilities to prevent + such panics? + A: No, get just the latest release of the driver and it should work + better and better with increasing version number. Forget about this + ibmmcascsi=forgiveall, as also ignorecmd are obsolete.! + Q: Linux panics or stops without any comment, but it is probable, that my + harddisk(s) have bad blocks. + A: Sorry, the bad-block handling is still a feeble point of this driver, + but is on the schedule for development in the near future. + Q: Linux panics while dynamically assigning SCSI-ids or ldns. + A: If you disconnect a SCSI-device from the machine, while Linux is up + and the driver uses dynamical reassignment of logical device numbers + (ldn), it really gets "angry" if it won't find devices, that were still + present at boottime and stops Linux. + Q: The system does not recover after an abort-command has been generated. + A: This is regrettably true, as it is not yet understood, why the + SCSI-adapter does really NOT generate any interrupt at the end of + the abort-command. As no interrupt is generated, the abort command + cannot get finished and the system hangs, sorry, but checks are + running to hunt down this problem. If there is a real pending command, + the interrupt MUST get generated after abort. In this case, it + should finish well. + Q: The system gets in bad shape after a SCSI-reset, is this known? + A: Yes, as there are a lot of prescriptions (see the Linux Hackers' + Guide) what has to be done for reset, we still share the bad shape of + the reset functions with all other low level SCSI-drivers. + Astonishingly, reset works in most cases quite ok, but the harddisks + won't run in synchonous mode anymore after a reset, until you reboot. + Q: Why does my XXX w/Cache adapter not use read-prefetch? + A: Ok, that is not completely possible. If a cache is present, the + adapter tries to use it internally. Explicitly, one can use the cache + with a read prefetch command, maybe in future, but this requires + some major overhead of SCSI-commands that risks the performance to + go down more than it gets improved. Tests with that are running. + Q: I have a IBM SCSI-2 Fast/Wide adapter, it boots in some way and hangs. + A: Yes, that is understood, as for sure, your SCSI-2 Fast/Wide adapter + was in such a case recognized as integrated SCSI-adapter or something + else, but not as the correct adapter. As the I/O-ports get assigned + wrongly by that reason, the system should crash in most cases. You + should upgrade to the latest release of the SCSI-driver. The + recommended version is 3.2 or later. Here, the F/W support is in + a stable and reliable condition. Wide-addressing is in addition + supported. + Q: I get a Ooops message and something like "killing interrupt". + A: The reason for this is that the IBM SCSI-subsystem only sends a + termination status back, if some error appeared. In former releases + of the driver, it was not checked, if the termination status block + is NULL. From version 3.2, it is taken care of this. + Q: I have a F/W adapter and the driver sees my internal SCSI-devices, + but ignores the external ones. + A: Select combined busmode in the IBM config-program and check for that + no SCSI-id on the external devices appears on internal devices. + Reboot afterwards. Dual busmode is supported, but works only for the + internal bus, yet. External bus is still ignored. Take care for your + SCSI-ids. If combined bus-mode is activated, on some adapters, + the wide-addressing is not possible, so devices with ids between 8 + and 15 get ignored by the driver & adapter! + Q: I have a 9595 and I get a NMI during heavy SCSI I/O e.g. during fsck. + A COMMAND ERROR is reported and characters on the screen are missing. + Warm reboot is not possible. Things look like quite weired. + A: Check the processor type of your 9595. If you have an 80486 or 486DX-2 + processor complex on your mainboard and you compiled a kernel that + supports 80386 processors, it is possible, that the kernel cannot + keep track of the PS/2 interrupt handling and stops on an NMI. Just + compile a kernel for the correct processor type of your PS/2 and + everything should be fine. This is necessary even if one assumes, + that some 80486 system should be downward compatible to 80386 + software. + Q: Some commands hang and interrupts block the machine. After some + timeout, the syslog reports that it tries to call abort, but the + machine is frozen. + A: This can be a busy wait bug in the interrupt handler of driver + version 3.2. You should at least upgrade to 3.2c if you use + kernel < 2.4.0 and driver version 4.0 if you use kernel 2.4.0 or + later (including all test releases). + Q: I have a PS/2 model 80 and more than 16 MBytes of RAM. The driver + completely refuses to work, reports NMIs, COMMAND ERRORs or other + ambiguous stuff. When reducing the RAM size down below 16 MB, + everything is running smoothly. + A: No real answer, yet. In any case, one should force the kernel to + present SCBs only below the 16 MBytes barrier. Maybe this solves the + problem. Not yet tried, but guessing that it could work. To get this, + set unchecked_isa_dma argument of ibmmca.h from 0 to 1. + + 5.3 Bugreports + -------------- + If you really find bugs in the sourcecode or the driver will successfully + refuse to work on your machine, you should send a bug report to me. The + best for this is to follow the instructions on the WWW-page for this + driver. Fill out the bug-report form, placed on the WWW-page and ship it, + so the bugs can be taken into account with maximum efforts. But, please + do not send bug reports about this driver to Linus Torvalds or Leonard + Zubkoff, as Linus is burried in E-Mail and Leonard is supervising all + SCSI-drivers and won't have the time left to look inside every single + driver to fix a bug and especially DO NOT send modified code to Linus + Torvalds or Alan J. Cox which has not been checked here!!! They are both + quite burried in E-mail (as me, sometimes, too) and one should first check + for problems on my local teststand. Recently, I got a lot of + bugreports for errors in the ibmmca.c code, which I could not imagine, but + a look inside some Linux-distribution showed me quite often some modified + code, which did no longer work on most other machines than the one of the + modifier. Ok, so now that there is maintenance service available for this + driver, please use this address first in order to keep the level of + confusion low. Thank you! + + When you get a SCSI-error message that panics your system, a list of + register-entries of the SCSI-subsystem is shown (from Version 3.1d). With + this list, it is very easy for the maintainer to localize the problem in + the driver or in the configuration of the user. Please write down all the + values from this report and send them to the maintainer. This would really + help a lot and makes life easier concerning misunderstandings. + + Use the bug-report form (see 5.4 for its address) to send all the bug- + stuff to the maintainer or write e-mail with the values from the table. + + 5.4 Support WWW-page + -------------------- + The address of the IBM SCSI-subsystem supporting WWW-page is: + + http://www.uni-mainz.de/~langm000/linux.html + + Here you can find info about the background of this driver, patches, + troubleshooting support, news and a bugreport form. Please check that + WWW-page regularly for latest hints. If ever this URL changes, please + refer to the MAINTAINERS file in order to get the latest address. + + For the bugreport, please fill out the formular on the corresponding + WWW-page. Read the dedicated instructions and write as much as you + know about your problem. If you do not like such formulars, please send + some e-mail directly, but at least with the same information as required by + the formular. + + If you have extensive bugreports, including Ooops messages and + screen-shots, please feel free to send it directly to the address + of the maintainer, too. The current address of the maintainer is: + + Michael Lang <langa2@kph.uni-mainz.de> + + 6 References + ------------ + IBM Corp., "Update for the PS/2 Hardware Interface Technical Reference, + Common Interfaces", Armonk, September 1991, PN 04G3281, + (available in the U.S. for $21.75 at 1-800-IBM-PCTB or in Germany for + around 40,-DM at "Hallo IBM"). + + IBM Corp., "Personal System/2 Micro Channel SCSI + Adapter with Cache Technical Reference", Armonk, March 1990, PN 68X2365. + + IBM Corp., "Personal System/2 Micro Channel SCSI + Adapter Technical Reference", Armonk, March 1990, PN 68X2397. + + IBM Corp., "SCSI-2 Fast/Wide Adapter/A Technical Reference - Dual Bus", + Armonk, March 1994, PN 83G7545. + + Friedhelm Schmidt, "SCSI-Bus und IDE-Schnittstelle - Moderne Peripherie- + Schnittstellen: Hardware, Protokollbeschreibung und Anwendung", 2. Aufl. + Addison Wesley, 1996. + + Michael K. Johnson, "The Linux Kernel Hackers' Guide", Version 0.6, Chapel + Hill - North Carolina, 1995 + + Andreas Kaiser, "SCSI TAPE BACKUP for OS/2 2.0", Version 2.12, Stuttgart + 1993 + + Helmut Rompel, "IBM Computerwelt GUIDE", What is what bei IBM., Systeme * + Programme * Begriffe, IWT-Verlag GmbH - Muenchen, 1988 + + 7 Credits to + ------------ + 7.1 People + ---------- + Klaus Grimm + who already a long time ago gave me the old code from the + SCSI-driver in order to get it running for some old machine + in our institute. + Martin Kolinek + who wrote the first release of the IBM SCSI-subsystem driver. + Chris Beauregard + who for a long time maintained MCA-Linux and the SCSI-driver + in the beginning. Chris, wherever you are: Cheers to you! + Klaus Kudielka + with whom in the 2.1.x times, I had a quite fruitful + cooperation to get the driver running as a module and to get + it running with multiple SCSI-adapters. + David Weinehall + for his excellent maintenance of the MCA-stuff and the quite + detailed bug reports and ideas for this driver (and his + patience ;-)). + Alan J. Cox + for his bugreports and his bold activities in cross-checking + the driver-code with his teststand. + + 7.2 Sponsors & Supporters + ------------------------- + "Hallo IBM", + IBM-Deutschland GmbH + the service of IBM-Deutschland for customers. Their E-Mail + service is unbeatable. Whatever old stuff I asked for, I + always got some helpful answers. + Karl-Otto Reimers, + IBM Klub - Sparte IBM Geschichte, Sindelfingen + for sending me a copy of the w/Cache manual from the + IBM-Deutschland archives. + Harald Staiger + for his extensive hardware donations which allows me today + still to test the driver in various constellations. + Erich Fritscher + for his very kind sponsoring. + Louis Ohland, + Charles Lasitter + for support by shipping me an IBM SCSI-2 Fast/Wide manual. + In addition, the contribution of various hardware is quite + decessive and will make it possible to add FWSR (RAID) + adapter support to the driver in the near future! So, + complaints about no RAID support won't remain forever. + Yes, folks, that is no joke, RAID support is going to rise! + Erik Weber + for the great deal we made about a model 9595 and the nice + surrounding equipment and the cool trip to Mannheim + second-hand computer market. In addition, I would like + to thank him for his exhaustive SCSI-driver testing on his + 95er PS/2 park. + Anthony Hogbin + for his direct shipment of a SCSI F/W adapter, which allowed + me immediately on the first stage to try it on model 8557 + together with onboard SCSI adapter and some SCSI w/Cache. + Andreas Hotz + for his support by memory and an IBM SCSI-adapter. Collecting + all this together now allows me to try really things with + the driver at maximum load and variety on various models in + a very quick and efficient way. + Peter Jennewein + for his model 30, which serves me as part of my teststand + and his cool remark about how you make an ordinary diskette + drive working and how to connect it to an IBM-diskette port. + Johannes Gutenberg-Universitaet, Mainz & + Institut fuer Kernphysik, Mainz Microtron (MAMI) + for the offered space, the link, placed on the central + homepage and the space to store and offer the driver and + related material and the free working times, which allow + me to answer all your e-mail. + + 8 Trademarks + ------------ + IBM, PS/2, OS/2, Microchannel are registered trademarks of International + Business Machines Corporation + + MS-DOS is a registered trademark of Microsoft Corporation + + Microware, OS-9 are registered trademarks of Microware Systems + + 9 Disclaimer + ------------ + Beside the GNU General Public License and the dependent disclaimers and disclaimers + concerning the Linux-kernel in special, this SCSI-driver comes without any + warranty. Its functionality is tested as good as possible on certain + machines and combinations of computer hardware, which does not exclude, + that dataloss or severe damage of hardware is possible while using this + part of software on some arbitrary computer hardware or in combination + with other software packages. It is highly recommended to make backup + copies of your data before using this software. Furthermore, personal + injuries by hardware defects, that could be caused by this SCSI-driver are + not excluded and it is highly recommended to handle this driver with a + maximum of carefulness. + + This driver supports hardware, produced by International Business Machines + Corporation (IBM). + +------ +Michael Lang +(langa2@kph.uni-mainz.de) |