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diff --git a/Documentation/mca.txt b/Documentation/mca.txt deleted file mode 100644 index dfd130c2207d..000000000000 --- a/Documentation/mca.txt +++ /dev/null @@ -1,313 +0,0 @@ -i386 Micro Channel Architecture Support -======================================= - -MCA support is enabled using the CONFIG_MCA define. A machine with a MCA -bus will have the kernel variable MCA_bus set, assuming the BIOS feature -bits are set properly (see arch/i386/boot/setup.S for information on -how this detection is done). - -Adapter Detection -================= - -The ideal MCA adapter detection is done through the use of the -Programmable Option Select registers. Generic functions for doing -this have been added in include/linux/mca.h and arch/x86/kernel/mca_32.c. -Everything needed to detect adapters and read (and write) configuration -information is there. A number of MCA-specific drivers already use -this. The typical probe code looks like the following: - - #include <linux/mca.h> - - unsigned char pos2, pos3, pos4, pos5; - struct net_device* dev; - int slot; - - if( MCA_bus ) { - slot = mca_find_adapter( ADAPTER_ID, 0 ); - if( slot == MCA_NOTFOUND ) { - return -ENODEV; - } - /* optional - see below */ - mca_set_adapter_name( slot, "adapter name & description" ); - mca_set_adapter_procfn( slot, dev_getinfo, dev ); - - /* read the POS registers. Most devices only use 2 and 3 */ - pos2 = mca_read_stored_pos( slot, 2 ); - pos3 = mca_read_stored_pos( slot, 3 ); - pos4 = mca_read_stored_pos( slot, 4 ); - pos5 = mca_read_stored_pos( slot, 5 ); - } else { - return -ENODEV; - } - - /* extract configuration from pos[2345] and set everything up */ - -Loadable modules should modify this to test that the specified IRQ and -IO ports (plus whatever other stuff) match. See 3c523.c for example -code (actually, smc-mca.c has a slightly more complex example that can -handle a list of adapter ids). - -Keep in mind that devices should never directly access the POS registers -(via inb(), outb(), etc). While it's generally safe, there is a small -potential for blowing up hardware when it's done at the wrong time. -Furthermore, accessing a POS register disables a device temporarily. -This is usually okay during startup, but do _you_ want to rely on it? -During initial configuration, mca_init() reads all the POS registers -into memory. mca_read_stored_pos() accesses that data. mca_read_pos() -and mca_write_pos() are also available for (safer) direct POS access, -but their use is _highly_ discouraged. mca_write_pos() is particularly -dangerous, as it is possible for adapters to be put in inconsistent -states (i.e. sharing IO address, etc) and may result in crashes, toasted -hardware, and blindness. - -User level drivers (such as the AGX X server) can use /proc/mca/pos to -find adapters (see below). - -Some MCA adapters can also be detected via the usual ISA-style device -probing (many SCSI adapters, for example). This sort of thing is highly -discouraged. Perfectly good information is available telling you what's -there, so there's no excuse for messing with random IO ports. However, -we MCA people still appreciate any ISA-style driver that will work with -our hardware. You take what you can get... - -Level-Triggered Interrupts -========================== - -Because MCA uses level-triggered interrupts, a few problems arise with -what might best be described as the ISA mindset and its effects on -drivers. These sorts of problems are expected to become less common as -more people use shared IRQs on PCI machines. - -In general, an interrupt must be acknowledged not only at the ICU (which -is done automagically by the kernel), but at the device level. In -particular, IRQ 0 must be reset after a timer interrupt (now done in -arch/x86/kernel/time.c) or the first timer interrupt hangs the system. -There were also problems with the 1.3.x floppy drivers, but that seems -to have been fixed. - -IRQs are also shareable, and most MCA-specific devices should be coded -with shared IRQs in mind. - -/proc/mca -========= - -/proc/mca is a directory containing various files for adapters and -other stuff. - - /proc/mca/pos Straight listing of POS registers - /proc/mca/slot[1-8] Information on adapter in specific slot - /proc/mca/video Same for integrated video - /proc/mca/scsi Same for integrated SCSI - /proc/mca/machine Machine information - -See Appendix A for a sample. - -Device drivers can easily add their own information function for -specific slots (including integrated ones) via the -mca_set_adapter_procfn() call. Drivers that support this are ESDI, IBM -SCSI, and 3c523. If a device is also a module, make sure that the proc -function is removed in the module cleanup. This will require storing -the slot information in a private structure somewhere. See the 3c523 -driver for details. - -Your typical proc function will look something like this: - - static int - dev_getinfo( char* buf, int slot, void* d ) { - struct net_device* dev = (struct net_device*) d; - int len = 0; - - len += sprintf( buf+len, "Device: %s\n", dev->name ); - len += sprintf( buf+len, "IRQ: %d\n", dev->irq ); - len += sprintf( buf+len, "IO Port: %#lx-%#lx\n", ... ); - ... - - return len; - } - -Some of the standard MCA information will already be printed, so don't -bother repeating it. Don't try putting in more than 3K of information. - -Enable this function with: - mca_set_adapter_procfn( slot, dev_getinfo, dev ); - -Disable it with: - mca_set_adapter_procfn( slot, NULL, NULL ); - -It is also recommended that, even if you don't write a proc function, to -set the name of the adapter (i.e. "PS/2 ESDI Controller") via -mca_set_adapter_name( int slot, char* name ). - -MCA Device Drivers -================== - -Currently, there are a number of MCA-specific device drivers. - -1) PS/2 SCSI - drivers/scsi/ibmmca.c - drivers/scsi/ibmmca.h - The driver for the IBM SCSI subsystem. Includes both integrated - controllers and adapter cards. May require command-line arg - "ibmmcascsi=io_port" to force detection of an adapter. If you have a - machine with a front-panel display (i.e. model 95), you can use - "ibmmcascsi=display" to enable a drive activity indicator. - -2) 3c523 - drivers/net/3c523.c - drivers/net/3c523.h - 3Com 3c523 Etherlink/MC ethernet driver. - -3) SMC Ultra/MCA and IBM Adapter/A - drivers/net/smc-mca.c - drivers/net/smc-mca.h - Driver for the MCA version of the SMC Ultra and various other - OEM'ed and work-alike cards (Elite, Adapter/A, etc). - -4) NE/2 - driver/net/ne2.c - driver/net/ne2.h - The NE/2 is the MCA version of the NE2000. This may not work - with clones that have a different adapter id than the original - NE/2. - -5) Future Domain MCS-600/700, OEM'd IBM Fast SCSI Adapter/A and - Reply Sound Blaster/SCSI (SCSI part) - Better support for these cards than the driver for ISA. - Supports multiple cards with IRQ sharing. - -Also added boot time option of scsi-probe, which can do reordering of -SCSI host adapters. This will direct the kernel on the order which -SCSI adapter should be detected. Example: - scsi-probe=ibmmca,fd_mcs,adaptec1542,buslogic - -The serial drivers were modified to support the extended IO port range -of the typical MCA system (also #ifdef CONFIG_MCA). - -The following devices work with existing drivers: -1) Token-ring -2) Future Domain SCSI (MCS-600, MCS-700, not MCS-350, OEM'ed IBM SCSI) -3) Adaptec 1640 SCSI (using the aha1542 driver) -4) Bustek/Buslogic SCSI (various) -5) Probably all Arcnet cards. -6) Some, possibly all, MCA IDE controllers. -7) 3Com 3c529 (MCA version of 3c509) (patched) - -8) Intel EtherExpressMC (patched version) - You need to have CONFIG_MCA defined to have EtherExpressMC support. -9) Reply Sound Blaster/SCSI (SB part) (patched version) - -Bugs & Other Weirdness -====================== - -NMIs tend to occur with MCA machines because of various hardware -weirdness, bus timeouts, and many other non-critical things. Some basic -code to handle them (inspired by the NetBSD MCA code) has been added to -detect the guilty device, but it's pretty incomplete. If NMIs are a -persistent problem (on some model 70 or 80s, they occur every couple -shell commands), the CONFIG_IGNORE_NMI flag will take care of that. - -Various Pentium machines have had serious problems with the FPU test in -bugs.h. Basically, the machine hangs after the HLT test. This occurs, -as far as we know, on the Pentium-equipped 85s, 95s, and some PC Servers. -The PCI/MCA PC 750s are fine as far as I can tell. The ``mca-pentium'' -boot-prompt flag will disable the FPU bug check if this is a problem -with your machine. - -The model 80 has a raft of problems that are just too weird and unique -to get into here. Some people have no trouble while others have nothing -but problems. I'd suspect some problems are related to the age of the -average 80 and accompanying hardware deterioration, although others -are definitely design problems with the hardware. Among the problems -include SCSI controller problems, ESDI controller problems, and serious -screw-ups in the floppy controller. Oh, and the parallel port is also -pretty flaky. There were about 5 or 6 different model 80 motherboards -produced to fix various obscure problems. As far as I know, it's pretty -much impossible to tell which bugs a particular model 80 has (other than -triggering them, that is). - -Drivers are required for some MCA memory adapters. If you're suddenly -short a few megs of RAM, this might be the reason. The (I think) Enhanced -Memory Adapter commonly found on the model 70 is one. There's a very -alpha driver floating around, but it's pretty ugly (disassembled from -the DOS driver, actually). See the MCA Linux web page (URL below) -for more current memory info. - -The Thinkpad 700 and 720 will work, but various components are either -non-functional, flaky, or we don't know anything about them. The -graphics controller is supposed to be some WD, but we can't get things -working properly. The PCMCIA slots don't seem to work. Ditto for APM. -The serial ports work, but detection seems to be flaky. - -Credits -======= -A whole pile of people have contributed to the MCA code. I'd include -their names here, but I don't have a list handy. Check the MCA Linux -home page (URL below) for a perpetually out-of-date list. - -===================================================================== -MCA Linux Home Page: http://www.dgmicro.com/mca/ - -Christophe Beauregard -chrisb@truespectra.com -cpbeaure@calum.csclub.uwaterloo.ca - -===================================================================== -Appendix A: Sample /proc/mca - -This is from my model 8595. Slot 1 contains the standard IBM SCSI -adapter, slot 3 is an Adaptec AHA-1640, slot 5 is a XGA-1 video adapter, -and slot 7 is the 3c523 Etherlink/MC. - -/proc/mca/machine: -Model Id: 0xf8 -Submodel Id: 0x14 -BIOS Revision: 0x5 - -/proc/mca/pos: -Slot 1: ff 8e f1 fc a0 ff ff ff IBM SCSI Adapter w/Cache -Slot 2: ff ff ff ff ff ff ff ff -Slot 3: 1f 0f 81 3b bf b6 ff ff -Slot 4: ff ff ff ff ff ff ff ff -Slot 5: db 8f 1d 5e fd c0 00 00 -Slot 6: ff ff ff ff ff ff ff ff -Slot 7: 42 60 ff 08 ff ff ff ff 3Com 3c523 Etherlink/MC -Slot 8: ff ff ff ff ff ff ff ff -Video : ff ff ff ff ff ff ff ff -SCSI : ff ff ff ff ff ff ff ff - -/proc/mca/slot1: -Slot: 1 -Adapter Name: IBM SCSI Adapter w/Cache -Id: 8eff -Enabled: Yes -POS: ff 8e f1 fc a0 ff ff ff -Subsystem PUN: 7 -Detected at boot: Yes - -/proc/mca/slot3: -Slot: 3 -Adapter Name: Unknown -Id: 0f1f -Enabled: Yes -POS: 1f 0f 81 3b bf b6 ff ff - -/proc/mca/slot5: -Slot: 5 -Adapter Name: Unknown -Id: 8fdb -Enabled: Yes -POS: db 8f 1d 5e fd c0 00 00 - -/proc/mca/slot7: -Slot: 7 -Adapter Name: 3Com 3c523 Etherlink/MC -Id: 6042 -Enabled: Yes -POS: 42 60 ff 08 ff ff ff ff -Revision: 0xe -IRQ: 9 -IO Address: 0x3300-0x3308 -Memory: 0xd8000-0xdbfff -Transceiver: External -Device: eth0 -Hardware Address: 02 60 8c 45 c4 2a |