1.. SPDX-License-Identifier: GPL-2.0 2.. include:: <isonum.txt> 3 4===================================================== 5Adaptec AHA-1520/1522 SCSI driver for Linux (aha152x) 6===================================================== 7 8Copyright |copy| 1993-1999 J��rgen Fischer <fischer@norbit.de> 9 10TC1550 patches by Luuk van Dijk (ldz@xs4all.nl) 11 12 13In Revision 2 the driver was modified a lot (especially the 14bottom-half handler complete()). 15 16The driver is much cleaner now, has support for the new 17error handling code in 2.3, produced less cpu load (much 18less polling loops), has slightly higher throughput (at 19least on my ancient test box; a i486/33Mhz/20MB). 20 21 22Configuration Arguments 23======================= 24 25============ ======================================== ====================== 26IOPORT base io address (0x340/0x140) 27IRQ interrupt level (9-12; default 11) 28SCSI_ID scsi id of controller (0-7; default 7) 29RECONNECT allow targets to disconnect from the bus (0/1; default 1 [on]) 30PARITY enable parity checking (0/1; default 1 [on]) 31SYNCHRONOUS enable synchronous transfers (0/1; default 1 [on]) 32DELAY: bus reset delay (default 100) 33EXT_TRANS: enable extended translation (0/1: default 0 [off]) 34 (see NOTES) 35============ ======================================== ====================== 36 37Compile Time Configuration 38========================== 39 40(go into AHA152X in drivers/scsi/Makefile): 41 42- DAUTOCONF 43 use configuration the controller reports (AHA-152x only) 44 45- DSKIP_BIOSTEST 46 Don't test for BIOS signature (AHA-1510 or disabled BIOS) 47 48- DSETUP0="{ IOPORT, IRQ, SCSI_ID, RECONNECT, PARITY, SYNCHRONOUS, DELAY, EXT_TRANS }" 49 override for the first controller 50 51- DSETUP1="{ IOPORT, IRQ, SCSI_ID, RECONNECT, PARITY, SYNCHRONOUS, DELAY, EXT_TRANS }" 52 override for the second controller 53 54- DAHA152X_DEBUG 55 enable debugging output 56 57- DAHA152X_STAT 58 enable some statistics 59 60 61LILO Command Line Options 62========================= 63 64 :: 65 66 aha152x=<IOPORT>[,<IRQ>[,<SCSI-ID>[,<RECONNECT>[,<PARITY>[,<SYNCHRONOUS>[,<DELAY> [,<EXT_TRANS]]]]]]] 67 68 The normal configuration can be overridden by specifying a command line. 69 When you do this, the BIOS test is skipped. Entered values have to be 70 valid (known). Don't use values that aren't supported under normal 71 operation. If you think that you need other values: contact me. 72 For two controllers use the aha152x statement twice. 73 74 75Symbols for Module Configuration 76================================ 77 78Choose from 2 alternatives: 79 801. specify everything (old):: 81 82 aha152x=IOPORT,IRQ,SCSI_ID,RECONNECT,PARITY,SYNCHRONOUS,DELAY,EXT_TRANS 83 84 configuration override for first controller 85 86 :: 87 88 aha152x1=IOPORT,IRQ,SCSI_ID,RECONNECT,PARITY,SYNCHRONOUS,DELAY,EXT_TRANS 89 90 configuration override for second controller 91 922. specify only what you need to (irq or io is required; new) 93 94io=IOPORT0[,IOPORT1] 95 IOPORT for first and second controller 96 97irq=IRQ0[,IRQ1] 98 IRQ for first and second controller 99 100scsiid=SCSIID0[,SCSIID1] 101 SCSIID for first and second controller 102 103reconnect=RECONNECT0[,RECONNECT1] 104 allow targets to disconnect for first and second controller 105 106parity=PAR0[PAR1] 107 use parity for first and second controller 108 109sync=SYNCHRONOUS0[,SYNCHRONOUS1] 110 enable synchronous transfers for first and second controller 111 112delay=DELAY0[,DELAY1] 113 reset DELAY for first and second controller 114 115exttrans=EXTTRANS0[,EXTTRANS1] 116 enable extended translation for first and second controller 117 118 119If you use both alternatives the first will be taken. 120 121 122Notes on EXT_TRANS 123================== 124 125SCSI uses block numbers to address blocks/sectors on a device. 126The BIOS uses a cylinder/head/sector addressing scheme (C/H/S) 127scheme instead. DOS expects a BIOS or driver that understands this 128C/H/S addressing. 129 130The number of cylinders/heads/sectors is called geometry and is required 131as base for requests in C/H/S addressing. SCSI only knows about the 132total capacity of disks in blocks (sectors). 133 134Therefore the SCSI BIOS/DOS driver has to calculate a logical/virtual 135geometry just to be able to support that addressing scheme. The geometry 136returned by the SCSI BIOS is a pure calculation and has nothing to 137do with the real/physical geometry of the disk (which is usually 138irrelevant anyway). 139 140Basically this has no impact at all on Linux, because it also uses block 141instead of C/H/S addressing. Unfortunately C/H/S addressing is also used 142in the partition table and therefore every operating system has to know 143the right geometry to be able to interpret it. 144 145Moreover there are certain limitations to the C/H/S addressing scheme, 146namely the address space is limited to up to 255 heads, up to 63 sectors 147and a maximum of 1023 cylinders. 148 149The AHA-1522 BIOS calculates the geometry by fixing the number of heads 150to 64, the number of sectors to 32 and by calculating the number of 151cylinders by dividing the capacity reported by the disk by 64*32 (1 MB). 152This is considered to be the default translation. 153 154With respect to the limit of 1023 cylinders using C/H/S you can only 155address the first GB of your disk in the partition table. Therefore 156BIOSes of some newer controllers based on the AIC-6260/6360 support 157extended translation. This means that the BIOS uses 255 for heads, 15863 for sectors and then divides the capacity of the disk by 255*63 159(about 8 MB), as soon it sees a disk greater than 1 GB. That results 160in a maximum of about 8 GB addressable diskspace in the partition table 161(but there are already bigger disks out there today). 162 163To make it even more complicated the translation mode might/might 164not be configurable in certain BIOS setups. 165 166This driver does some more or less failsafe guessing to get the 167geometry right in most cases: 168 169- for disks<1GB: use default translation (C/32/64) 170 171- for disks>1GB: 172 173 - take current geometry from the partition table 174 (using scsicam_bios_param and accept only 'valid' geometries, 175 ie. either (C/32/64) or (C/63/255)). This can be extended translation 176 even if it's not enabled in the driver. 177 178 - if that fails, take extended translation if enabled by override, 179 kernel or module parameter, otherwise take default translation and 180 ask the user for verification. This might on not yet partitioned 181 disks. 182 183 184References Used 185=============== 186 187 "AIC-6260 SCSI Chip Specification", Adaptec Corporation. 188 189 "SCSI COMPUTER SYSTEM INTERFACE - 2 (SCSI-2)", X3T9.2/86-109 rev. 10h 190 191 "Writing a SCSI device driver for Linux", Rik Faith (faith@cs.unc.edu) 192 193 "Kernel Hacker's Guide", Michael K. Johnson (johnsonm@sunsite.unc.edu) 194 195 "Adaptec 1520/1522 User's Guide", Adaptec Corporation. 196 197 Michael K. Johnson (johnsonm@sunsite.unc.edu) 198 199 Drew Eckhardt (drew@cs.colorado.edu) 200 201 Eric Youngdale (eric@andante.org) 202 203 special thanks to Eric Youngdale for the free(!) supplying the 204 documentation on the chip. 205