1 2 Linux and parallel port IDE devices 3 4PARIDE v1.03 (c) 1997-8 Grant Guenther <grant@torque.net> 5 61. Introduction 7 8Owing to the simplicity and near universality of the parallel port interface 9to personal computers, many external devices such as portable hard-disk, 10CD-ROM, LS-120 and tape drives use the parallel port to connect to their 11host computer. While some devices (notably scanners) use ad-hoc methods 12to pass commands and data through the parallel port interface, most 13external devices are actually identical to an internal model, but with 14a parallel-port adapter chip added in. Some of the original parallel port 15adapters were little more than mechanisms for multiplexing a SCSI bus. 16(The Iomega PPA-3 adapter used in the ZIP drives is an example of this 17approach). Most current designs, however, take a different approach. 18The adapter chip reproduces a small ISA or IDE bus in the external device 19and the communication protocol provides operations for reading and writing 20device registers, as well as data block transfer functions. Sometimes, 21the device being addressed via the parallel cable is a standard SCSI 22controller like an NCR 5380. The "ditto" family of external tape 23drives use the ISA replicator to interface a floppy disk controller, 24which is then connected to a floppy-tape mechanism. The vast majority 25of external parallel port devices, however, are now based on standard 26IDE type devices, which require no intermediate controller. If one 27were to open up a parallel port CD-ROM drive, for instance, one would 28find a standard ATAPI CD-ROM drive, a power supply, and a single adapter 29that interconnected a standard PC parallel port cable and a standard 30IDE cable. It is usually possible to exchange the CD-ROM device with 31any other device using the IDE interface. 32 33The document describes the support in Linux for parallel port IDE 34devices. It does not cover parallel port SCSI devices, "ditto" tape 35drives or scanners. Many different devices are supported by the 36parallel port IDE subsystem, including: 37 38 MicroSolutions backpack CD-ROM 39 MicroSolutions backpack PD/CD 40 MicroSolutions backpack hard-drives 41 MicroSolutions backpack 8000t tape drive 42 SyQuest EZ-135, EZ-230 & SparQ drives 43 Avatar Shark 44 Imation Superdisk LS-120 45 Maxell Superdisk LS-120 46 FreeCom Power CD 47 Hewlett-Packard 5GB and 8GB tape drives 48 Hewlett-Packard 7100 and 7200 CD-RW drives 49 50as well as most of the clone and no-name products on the market. 51 52To support such a wide range of devices, PARIDE, the parallel port IDE 53subsystem, is actually structured in three parts. There is a base 54paride module which provides a registry and some common methods for 55accessing the parallel ports. The second component is a set of 56high-level drivers for each of the different types of supported devices: 57 58 pd IDE disk 59 pcd ATAPI CD-ROM 60 pf ATAPI disk 61 pt ATAPI tape 62 pg ATAPI generic 63 64(Currently, the pg driver is only used with CD-R drives). 65 66The high-level drivers function according to the relevant standards. 67The third component of PARIDE is a set of low-level protocol drivers 68for each of the parallel port IDE adapter chips. Thanks to the interest 69and encouragement of Linux users from many parts of the world, 70support is available for almost all known adapter protocols: 71 72 aten ATEN EH-100 (HK) 73 bpck Microsolutions backpack (US) 74 comm DataStor (old-type) "commuter" adapter (TW) 75 dstr DataStor EP-2000 (TW) 76 epat Shuttle EPAT (UK) 77 epia Shuttle EPIA (UK) 78 fit2 FIT TD-2000 (US) 79 fit3 FIT TD-3000 (US) 80 friq Freecom IQ cable (DE) 81 frpw Freecom Power (DE) 82 kbic KingByte KBIC-951A and KBIC-971A (TW) 83 ktti KT Technology PHd adapter (SG) 84 on20 OnSpec 90c20 (US) 85 on26 OnSpec 90c26 (US) 86 87 882. Using the PARIDE subsystem 89 90While configuring the Linux kernel, you may choose either to build 91the PARIDE drivers into your kernel, or to build them as modules. 92 93In either case, you will need to select "Parallel port IDE device support" 94as well as at least one of the high-level drivers and at least one 95of the parallel port communication protocols. If you do not know 96what kind of parallel port adapter is used in your drive, you could 97begin by checking the file names and any text files on your DOS 98installation floppy. Alternatively, you can look at the markings on 99the adapter chip itself. That's usually sufficient to identify the 100correct device. 101 102You can actually select all the protocol modules, and allow the PARIDE 103subsystem to try them all for you. 104 105For the "brand-name" products listed above, here are the protocol 106and high-level drivers that you would use: 107 108 Manufacturer Model Driver Protocol 109 110 MicroSolutions CD-ROM pcd bpck 111 MicroSolutions PD drive pf bpck 112 MicroSolutions hard-drive pd bpck 113 MicroSolutions 8000t tape pt bpck 114 SyQuest EZ, SparQ pd epat 115 Imation Superdisk pf epat 116 Maxell Superdisk pf friq 117 Avatar Shark pd epat 118 FreeCom CD-ROM pcd frpw 119 Hewlett-Packard 5GB Tape pt epat 120 Hewlett-Packard 7200e (CD) pcd epat 121 Hewlett-Packard 7200e (CD-R) pg epat 122 1232.1 Configuring built-in drivers 124 125We recommend that you get to know how the drivers work and how to 126configure them as loadable modules, before attempting to compile a 127kernel with the drivers built-in. 128 129If you built all of your PARIDE support directly into your kernel, 130and you have just a single parallel port IDE device, your kernel should 131locate it automatically for you. If you have more than one device, 132you may need to give some command line options to your bootloader 133(eg: LILO), how to do that is beyond the scope of this document. 134 135The high-level drivers accept a number of command line parameters, all 136of which are documented in the source files in linux/drivers/block/paride. 137By default, each driver will automatically try all parallel ports it 138can find, and all protocol types that have been installed, until it finds 139a parallel port IDE adapter. Once it finds one, the probe stops. So, 140if you have more than one device, you will need to tell the drivers 141how to identify them. This requires specifying the port address, the 142protocol identification number and, for some devices, the drive's 143chain ID. While your system is booting, a number of messages are 144displayed on the console. Like all such messages, they can be 145reviewed with the 'dmesg' command. Among those messages will be 146some lines like: 147 148 paride: bpck registered as protocol 0 149 paride: epat registered as protocol 1 150 151The numbers will always be the same until you build a new kernel with 152different protocol selections. You should note these numbers as you 153will need them to identify the devices. 154 155If you happen to be using a MicroSolutions backpack device, you will 156also need to know the unit ID number for each drive. This is usually 157the last two digits of the drive's serial number (but read MicroSolutions' 158documentation about this). 159 160As an example, let's assume that you have a MicroSolutions PD/CD drive 161with unit ID number 36 connected to the parallel port at 0x378, a SyQuest 162EZ-135 connected to the chained port on the PD/CD drive and also an 163Imation Superdisk connected to port 0x278. You could give the following 164options on your boot command: 165 166 pd.drive0=0x378,1 pf.drive0=0x278,1 pf.drive1=0x378,0,36 167 168In the last option, pf.drive1 configures device /dev/pf1, the 0x378 169is the parallel port base address, the 0 is the protocol registration 170number and 36 is the chain ID. 171 172Please note: while PARIDE will work both with and without the 173PARPORT parallel port sharing system that is included by the 174"Parallel port support" option, PARPORT must be included and enabled 175if you want to use chains of devices on the same parallel port. 176 1772.2 Loading and configuring PARIDE as modules 178 179It is much faster and simpler to get to understand the PARIDE drivers 180if you use them as loadable kernel modules. 181 182Note 1: using these drivers with the "kerneld" automatic module loading 183system is not recommended for beginners, and is not documented here. 184 185Note 2: if you build PARPORT support as a loadable module, PARIDE must 186also be built as loadable modules, and PARPORT must be loaded before the 187PARIDE modules. 188 189To use PARIDE, you must begin by 190 191 insmod paride 192 193this loads a base module which provides a registry for the protocols, 194among other tasks. 195 196Then, load as many of the protocol modules as you think you might need. 197As you load each module, it will register the protocols that it supports, 198and print a log message to your kernel log file and your console. For 199example: 200 201 # insmod epat 202 paride: epat registered as protocol 0 203 # insmod kbic 204 paride: k951 registered as protocol 1 205 paride: k971 registered as protocol 2 206 207Finally, you can load high-level drivers for each kind of device that 208you have connected. By default, each driver will autoprobe for a single 209device, but you can support up to four similar devices by giving their 210individual co-ordinates when you load the driver. 211 212For example, if you had two no-name CD-ROM drives both using the 213KingByte KBIC-951A adapter, one on port 0x378 and the other on 0x3bc 214you could give the following command: 215 216 # insmod pcd drive0=0x378,1 drive1=0x3bc,1 217 218For most adapters, giving a port address and protocol number is sufficient, 219but check the source files in linux/drivers/block/paride for more 220information. (Hopefully someone will write some man pages one day !). 221 222As another example, here's what happens when PARPORT is installed, and 223a SyQuest EZ-135 is attached to port 0x378: 224 225 # insmod paride 226 paride: version 1.0 installed 227 # insmod epat 228 paride: epat registered as protocol 0 229 # insmod pd 230 pd: pd version 1.0, major 45, cluster 64, nice 0 231 pda: Sharing parport1 at 0x378 232 pda: epat 1.0, Shuttle EPAT chip c3 at 0x378, mode 5 (EPP-32), delay 1 233 pda: SyQuest EZ135A, 262144 blocks [128M], (512/16/32), removable media 234 pda: pda1 235 236Note that the last line is the output from the generic partition table 237scanner - in this case it reports that it has found a disk with one partition. 238 2392.3 Using a PARIDE device 240 241Once the drivers have been loaded, you can access PARIDE devices in the 242same way as their traditional counterparts. You will probably need to 243create the device "special files". Here is a simple script that you can 244cut to a file and execute: 245 246#!/bin/bash 247# 248# mkd -- a script to create the device special files for the PARIDE subsystem 249# 250function mkdev { 251 mknod $1 $2 $3 $4 ; chmod 0660 $1 ; chown root:disk $1 252} 253# 254function pd { 255 D=$( printf \\$( printf "x%03x" $[ $1 + 97 ] ) ) 256 mkdev pd$D b 45 $[ $1 * 16 ] 257 for P in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 258 do mkdev pd$D$P b 45 $[ $1 * 16 + $P ] 259 done 260} 261# 262cd /dev 263# 264for u in 0 1 2 3 ; do pd $u ; done 265for u in 0 1 2 3 ; do mkdev pcd$u b 46 $u ; done 266for u in 0 1 2 3 ; do mkdev pf$u b 47 $u ; done 267for u in 0 1 2 3 ; do mkdev pt$u c 96 $u ; done 268for u in 0 1 2 3 ; do mkdev npt$u c 96 $[ $u + 128 ] ; done 269for u in 0 1 2 3 ; do mkdev pg$u c 97 $u ; done 270# 271# end of mkd 272 273With the device files and drivers in place, you can access PARIDE devices 274like any other Linux device. For example, to mount a CD-ROM in pcd0, use: 275 276 mount /dev/pcd0 /cdrom 277 278If you have a fresh Avatar Shark cartridge, and the drive is pda, you 279might do something like: 280 281 fdisk /dev/pda -- make a new partition table with 282 partition 1 of type 83 283 284 mke2fs /dev/pda1 -- to build the file system 285 286 mkdir /shark -- make a place to mount the disk 287 288 mount /dev/pda1 /shark 289 290Devices like the Imation superdisk work in the same way, except that 291they do not have a partition table. For example to make a 120MB 292floppy that you could share with a DOS system: 293 294 mkdosfs /dev/pf0 295 mount /dev/pf0 /mnt 296 297 2982.4 The pf driver 299 300The pf driver is intended for use with parallel port ATAPI disk 301devices. The most common devices in this category are PD drives 302and LS-120 drives. Traditionally, media for these devices are not 303partitioned. Consequently, the pf driver does not support partitioned 304media. This may be changed in a future version of the driver. 305 3062.5 Using the pt driver 307 308The pt driver for parallel port ATAPI tape drives is a minimal driver. 309It does not yet support many of the standard tape ioctl operations. 310For best performance, a block size of 32KB should be used. You will 311probably want to set the parallel port delay to 0, if you can. 312 3132.6 Using the pg driver 314 315The pg driver can be used in conjunction with the cdrecord program 316to create CD-ROMs. Please get cdrecord version 1.6.1 or later 317from ftp://ftp.fokus.gmd.de/pub/unix/cdrecord/ . To record CD-R media 318your parallel port should ideally be set to EPP mode, and the "port delay" 319should be set to 0. With those settings it is possible to record at 2x 320speed without any buffer underruns. If you cannot get the driver to work 321in EPP mode, try to use "bidirectional" or "PS/2" mode and 1x speeds only. 322 323 3243. Troubleshooting 325 3263.1 Use EPP mode if you can 327 328The most common problems that people report with the PARIDE drivers 329concern the parallel port CMOS settings. At this time, none of the 330PARIDE protocol modules support ECP mode, or any ECP combination modes. 331If you are able to do so, please set your parallel port into EPP mode 332using your CMOS setup procedure. 333 3343.2 Check the port delay 335 336Some parallel ports cannot reliably transfer data at full speed. To 337offset the errors, the PARIDE protocol modules introduce a "port 338delay" between each access to the i/o ports. Each protocol sets 339a default value for this delay. In most cases, the user can override 340the default and set it to 0 - resulting in somewhat higher transfer 341rates. In some rare cases (especially with older 486 systems) the 342default delays are not long enough. if you experience corrupt data 343transfers, or unexpected failures, you may wish to increase the 344port delay. The delay can be programmed using the "driveN" parameters 345to each of the high-level drivers. Please see the notes above, or 346read the comments at the beginning of the driver source files in 347linux/drivers/block/paride. 348 3493.3 Some drives need a printer reset 350 351There appear to be a number of "noname" external drives on the market 352that do not always power up correctly. We have noticed this with some 353drives based on OnSpec and older Freecom adapters. In these rare cases, 354the adapter can often be reinitialised by issuing a "printer reset" on 355the parallel port. As the reset operation is potentially disruptive in 356multiple device environments, the PARIDE drivers will not do it 357automatically. You can however, force a printer reset by doing: 358 359 insmod lp reset=1 360 rmmod lp 361 362If you have one of these marginal cases, you should probably build 363your paride drivers as modules, and arrange to do the printer reset 364before loading the PARIDE drivers. 365 3663.4 Use the verbose option and dmesg if you need help 367 368While a lot of testing has gone into these drivers to make them work 369as smoothly as possible, problems will arise. If you do have problems, 370please check all the obvious things first: does the drive work in 371DOS with the manufacturer's drivers ? If that doesn't yield any useful 372clues, then please make sure that only one drive is hooked to your system, 373and that either (a) PARPORT is enabled or (b) no other device driver 374is using your parallel port (check in /proc/ioports). Then, load the 375appropriate drivers (you can load several protocol modules if you want) 376as in: 377 378 # insmod paride 379 # insmod epat 380 # insmod bpck 381 # insmod kbic 382 ... 383 # insmod pd verbose=1 384 385(using the correct driver for the type of device you have, of course). 386The verbose=1 parameter will cause the drivers to log a trace of their 387activity as they attempt to locate your drive. 388 389Use 'dmesg' to capture a log of all the PARIDE messages (any messages 390beginning with paride:, a protocol module's name or a driver's name) and 391include that with your bug report. You can submit a bug report in one 392of two ways. Either send it directly to the author of the PARIDE suite, 393by e-mail to grant@torque.net, or join the linux-parport mailing list 394and post your report there. 395 3963.5 For more information or help 397 398You can join the linux-parport mailing list by sending a mail message 399to 400 linux-parport-request@torque.net 401 402with the single word 403 404 subscribe 405 406in the body of the mail message (not in the subject line). Please be 407sure that your mail program is correctly set up when you do this, as 408the list manager is a robot that will subscribe you using the reply 409address in your mail headers. REMOVE any anti-spam gimmicks you may 410have in your mail headers, when sending mail to the list server. 411 412You might also find some useful information on the linux-parport 413web pages (although they are not always up to date) at 414 415 http://www.torque.net/parport/ 416 417 418