| .. SPDX-License-Identifier: GPL-2.0 |
| .. include:: <isonum.txt> |
| |
| ===================================================== |
| Adaptec AHA-1520/1522 SCSI driver for Linux (aha152x) |
| ===================================================== |
| |
| Copyright |copy| 1993-1999 Jürgen Fischer <fischer@norbit.de> |
| |
| TC1550 patches by Luuk van Dijk (ldz@xs4all.nl) |
| |
| |
| In Revision 2 the driver was modified a lot (especially the |
| bottom-half handler complete()). |
| |
| The driver is much cleaner now, has support for the new |
| error handling code in 2.3, produced less cpu load (much |
| less polling loops), has slightly higher throughput (at |
| least on my ancient test box; a i486/33Mhz/20MB). |
| |
| |
| Configuration Arguments |
| ======================= |
| |
| ============ ======================================== ====================== |
| IOPORT base io address (0x340/0x140) |
| IRQ interrupt level (9-12; default 11) |
| SCSI_ID scsi id of controller (0-7; default 7) |
| RECONNECT allow targets to disconnect from the bus (0/1; default 1 [on]) |
| PARITY enable parity checking (0/1; default 1 [on]) |
| SYNCHRONOUS enable synchronous transfers (0/1; default 1 [on]) |
| DELAY: bus reset delay (default 100) |
| EXT_TRANS: enable extended translation (0/1: default 0 [off]) |
| (see NOTES) |
| ============ ======================================== ====================== |
| |
| Compile Time Configuration |
| ========================== |
| |
| (go into AHA152X in drivers/scsi/Makefile): |
| |
| - DAUTOCONF |
| use configuration the controller reports (AHA-152x only) |
| |
| - DSKIP_BIOSTEST |
| Don't test for BIOS signature (AHA-1510 or disabled BIOS) |
| |
| - DSETUP0="{ IOPORT, IRQ, SCSI_ID, RECONNECT, PARITY, SYNCHRONOUS, DELAY, EXT_TRANS }" |
| override for the first controller |
| |
| - DSETUP1="{ IOPORT, IRQ, SCSI_ID, RECONNECT, PARITY, SYNCHRONOUS, DELAY, EXT_TRANS }" |
| override for the second controller |
| |
| - DAHA152X_DEBUG |
| enable debugging output |
| |
| - DAHA152X_STAT |
| enable some statistics |
| |
| |
| LILO Command Line Options |
| ========================= |
| |
| :: |
| |
| aha152x=<IOPORT>[,<IRQ>[,<SCSI-ID>[,<RECONNECT>[,<PARITY>[,<SYNCHRONOUS>[,<DELAY> [,<EXT_TRANS]]]]]]] |
| |
| The normal configuration can be overridden by specifying a command line. |
| When you do this, the BIOS test is skipped. Entered values have to be |
| valid (known). Don't use values that aren't supported under normal |
| operation. If you think that you need other values: contact me. |
| For two controllers use the aha152x statement twice. |
| |
| |
| Symbols for Module Configuration |
| ================================ |
| |
| Choose from 2 alternatives: |
| |
| 1. specify everything (old):: |
| |
| aha152x=IOPORT,IRQ,SCSI_ID,RECONNECT,PARITY,SYNCHRONOUS,DELAY,EXT_TRANS |
| |
| configuration override for first controller |
| |
| :: |
| |
| aha152x1=IOPORT,IRQ,SCSI_ID,RECONNECT,PARITY,SYNCHRONOUS,DELAY,EXT_TRANS |
| |
| configuration override for second controller |
| |
| 2. specify only what you need to (irq or io is required; new) |
| |
| io=IOPORT0[,IOPORT1] |
| IOPORT for first and second controller |
| |
| irq=IRQ0[,IRQ1] |
| IRQ for first and second controller |
| |
| scsiid=SCSIID0[,SCSIID1] |
| SCSIID for first and second controller |
| |
| reconnect=RECONNECT0[,RECONNECT1] |
| allow targets to disconnect for first and second controller |
| |
| parity=PAR0[PAR1] |
| use parity for first and second controller |
| |
| sync=SYNCHRONOUS0[,SYNCHRONOUS1] |
| enable synchronous transfers for first and second controller |
| |
| delay=DELAY0[,DELAY1] |
| reset DELAY for first and second controller |
| |
| exttrans=EXTTRANS0[,EXTTRANS1] |
| enable extended translation for first and second controller |
| |
| |
| If you use both alternatives the first will be taken. |
| |
| |
| Notes on EXT_TRANS |
| ================== |
| |
| SCSI uses block numbers to address blocks/sectors on a device. |
| The BIOS uses a cylinder/head/sector addressing scheme (C/H/S) |
| scheme instead. DOS expects a BIOS or driver that understands this |
| C/H/S addressing. |
| |
| The number of cylinders/heads/sectors is called geometry and is required |
| as base for requests in C/H/S addressing. SCSI only knows about the |
| total capacity of disks in blocks (sectors). |
| |
| Therefore the SCSI BIOS/DOS driver has to calculate a logical/virtual |
| geometry just to be able to support that addressing scheme. The geometry |
| returned by the SCSI BIOS is a pure calculation and has nothing to |
| do with the real/physical geometry of the disk (which is usually |
| irrelevant anyway). |
| |
| Basically this has no impact at all on Linux, because it also uses block |
| instead of C/H/S addressing. Unfortunately C/H/S addressing is also used |
| in the partition table and therefore every operating system has to know |
| the right geometry to be able to interpret it. |
| |
| Moreover there are certain limitations to the C/H/S addressing scheme, |
| namely the address space is limited to up to 255 heads, up to 63 sectors |
| and a maximum of 1023 cylinders. |
| |
| The AHA-1522 BIOS calculates the geometry by fixing the number of heads |
| to 64, the number of sectors to 32 and by calculating the number of |
| cylinders by dividing the capacity reported by the disk by 64*32 (1 MB). |
| This is considered to be the default translation. |
| |
| With respect to the limit of 1023 cylinders using C/H/S you can only |
| address the first GB of your disk in the partition table. Therefore |
| BIOSes of some newer controllers based on the AIC-6260/6360 support |
| extended translation. This means that the BIOS uses 255 for heads, |
| 63 for sectors and then divides the capacity of the disk by 255*63 |
| (about 8 MB), as soon it sees a disk greater than 1 GB. That results |
| in a maximum of about 8 GB addressable diskspace in the partition table |
| (but there are already bigger disks out there today). |
| |
| To make it even more complicated the translation mode might/might |
| not be configurable in certain BIOS setups. |
| |
| This driver does some more or less failsafe guessing to get the |
| geometry right in most cases: |
| |
| - for disks<1GB: use default translation (C/32/64) |
| |
| - for disks>1GB: |
| |
| - take current geometry from the partition table |
| (using scsicam_bios_param and accept only 'valid' geometries, |
| ie. either (C/32/64) or (C/63/255)). This can be extended translation |
| even if it's not enabled in the driver. |
| |
| - if that fails, take extended translation if enabled by override, |
| kernel or module parameter, otherwise take default translation and |
| ask the user for verification. This might on not yet partitioned |
| disks. |
| |
| |
| References Used |
| =============== |
| |
| "AIC-6260 SCSI Chip Specification", Adaptec Corporation. |
| |
| "SCSI COMPUTER SYSTEM INTERFACE - 2 (SCSI-2)", X3T9.2/86-109 rev. 10h |
| |
| "Writing a SCSI device driver for Linux", Rik Faith (faith@cs.unc.edu) |
| |
| "Kernel Hacker's Guide", Michael K. Johnson (johnsonm@sunsite.unc.edu) |
| |
| "Adaptec 1520/1522 User's Guide", Adaptec Corporation. |
| |
| Michael K. Johnson (johnsonm@sunsite.unc.edu) |
| |
| Drew Eckhardt (drew@cs.colorado.edu) |
| |
| Eric Youngdale (eric@andante.org) |
| |
| special thanks to Eric Youngdale for the free(!) supplying the |
| documentation on the chip. |
