1 2 Information regarding the Enhanced IDE drive in Linux 2.6 3 4============================================================================== 5 6 7 The hdparm utility can be used to control various IDE features on a 8 running system. It is packaged separately. Please Look for it on popular 9 linux FTP sites. 10 11 12 13*** IMPORTANT NOTICES: BUGGY IDE CHIPSETS CAN CORRUPT DATA!! 14*** ================= 15*** PCI versions of the CMD640 and RZ1000 interfaces are now detected 16*** automatically at startup when PCI BIOS support is configured. 17*** 18*** Linux disables the "prefetch" ("readahead") mode of the RZ1000 19*** to prevent data corruption possible due to hardware design flaws. 20*** 21*** For the CMD640, linux disables "IRQ unmasking" (hdparm -u1) on any 22*** drive for which the "prefetch" mode of the CMD640 is turned on. 23*** If "prefetch" is disabled (hdparm -p8), then "IRQ unmasking" can be 24*** used again. 25*** 26*** For the CMD640, linux disables "32bit I/O" (hdparm -c1) on any drive 27*** for which the "prefetch" mode of the CMD640 is turned off. 28*** If "prefetch" is enabled (hdparm -p9), then "32bit I/O" can be 29*** used again. 30*** 31*** The CMD640 is also used on some Vesa Local Bus (VLB) cards, and is *NOT* 32*** automatically detected by Linux. For safe, reliable operation with such 33*** interfaces, one *MUST* use the "ide0=cmd640_vlb" kernel option. 34*** 35*** Use of the "serialize" option is no longer necessary. 36 37================================================================================ 38Common pitfalls: 39 40- 40-conductor IDE cables are capable of transferring data in DMA modes up to 41 udma2, but no faster. 42 43- If possible devices should be attached to separate channels if they are 44 available. Typically the disk on the first and CD-ROM on the second. 45 46- If you mix devices on the same cable, please consider using similar devices 47 in respect of the data transfer mode they support. 48 49- Even better try to stick to the same vendor and device type on the same 50 cable. 51 52================================================================================ 53 54This is the multiple IDE interface driver, as evolved from hd.c. 55 56It supports up to 9 IDE interfaces per default, on one or more IRQs (usually 5714 & 15). There can be up to two drives per interface, as per the ATA-6 spec. 58 59Primary: ide0, port 0x1f0; major=3; hda is minor=0; hdb is minor=64 60Secondary: ide1, port 0x170; major=22; hdc is minor=0; hdd is minor=64 61Tertiary: ide2, port 0x1e8; major=33; hde is minor=0; hdf is minor=64 62Quaternary: ide3, port 0x168; major=34; hdg is minor=0; hdh is minor=64 63fifth.. ide4, usually PCI, probed 64sixth.. ide5, usually PCI, probed 65 66To access devices on interfaces > ide0, device entries please make sure that 67device files for them are present in /dev. If not, please create such 68entries, by using /dev/MAKEDEV. 69 70This driver automatically probes for most IDE interfaces (including all PCI 71ones), for the drives/geometries attached to those interfaces, and for the IRQ 72lines being used by the interfaces (normally 14, 15 for ide0/ide1). 73 74For special cases, interfaces may be specified using kernel "command line" 75options. For example, 76 77 ide3=0x168,0x36e,10 /* ioports 0x168-0x16f,0x36e, irq 10 */ 78 79Normally the irq number need not be specified, as ide.c will probe for it: 80 81 ide3=0x168,0x36e /* ioports 0x168-0x16f,0x36e */ 82 83The standard port, and irq values are these: 84 85 ide0=0x1f0,0x3f6,14 86 ide1=0x170,0x376,15 87 ide2=0x1e8,0x3ee,11 88 ide3=0x168,0x36e,10 89 90Note that the first parameter reserves 8 contiguous ioports, whereas the 91second value denotes a single ioport. If in doubt, do a 'cat /proc/ioports'. 92 93In all probability the device uses these ports and IRQs if it is attached 94to the appropriate ide channel. Pass the parameter for the correct ide 95channel to the kernel, as explained above. 96 97Any number of interfaces may share a single IRQ if necessary, at a slight 98performance penalty, whether on separate cards or a single VLB card. 99The IDE driver automatically detects and handles this. However, this may 100or may not be harmful to your hardware.. two or more cards driving the same IRQ 101can potentially burn each other's bus driver, though in practice this 102seldom occurs. Be careful, and if in doubt, don't do it! 103 104Drives are normally found by auto-probing and/or examining the CMOS/BIOS data. 105For really weird situations, the apparent (fdisk) geometry can also be specified 106on the kernel "command line" using LILO. The format of such lines is: 107 108 hdx=cyls,heads,sects,wpcom,irq 109or hdx=cdrom 110 111where hdx can be any of hda through hdh, Three values are required 112(cyls,heads,sects). For example: 113 114 hdc=1050,32,64 hdd=cdrom 115 116either {hda,hdb} or {hdc,hdd}. The results of successful auto-probing may 117override the physical geometry/irq specified, though the "original" geometry 118may be retained as the "logical" geometry for partitioning purposes (fdisk). 119 120If the auto-probing during boot time confuses a drive (ie. the drive works 121with hd.c but not with ide.c), then an command line option may be specified 122for each drive for which you'd like the drive to skip the hardware 123probe/identification sequence. For example: 124 125 hdb=noprobe 126or 127 hdc=768,16,32 128 hdc=noprobe 129 130Note that when only one IDE device is attached to an interface, it should be 131jumpered as "single" or "master", *not* "slave". Many folks have had 132"trouble" with cdroms because of this requirement, so the driver now probes 133for both units, though success is more likely when the drive is jumpered 134correctly. 135 136Courtesy of Scott Snyder and others, the driver supports ATAPI cdrom drives 137such as the NEC-260 and the new MITSUMI triple/quad speed drives. 138Such drives will be identified at boot time, just like a hard disk. 139 140If for some reason your cdrom drive is *not* found at boot time, you can force 141the probe to look harder by supplying a kernel command line parameter 142via LILO, such as: 143 144 hdc=cdrom /* hdc = "master" on second interface */ 145or 146 hdd=cdrom /* hdd = "slave" on second interface */ 147 148For example, a GW2000 system might have a hard drive on the primary 149interface (/dev/hda) and an IDE cdrom drive on the secondary interface 150(/dev/hdc). To mount a CD in the cdrom drive, one would use something like: 151 152 ln -sf /dev/hdc /dev/cdrom 153 mkdir /mnt/cdrom 154 mount /dev/cdrom /mnt/cdrom -t iso9660 -o ro 155 156If, after doing all of the above, mount doesn't work and you see 157errors from the driver (with dmesg) complaining about `status=0xff', 158this means that the hardware is not responding to the driver's attempts 159to read it. One of the following is probably the problem: 160 161 - Your hardware is broken. 162 163 - You are using the wrong address for the device, or you have the 164 drive jumpered wrong. Review the configuration instructions above. 165 166 - Your IDE controller requires some nonstandard initialization sequence 167 before it will work properly. If this is the case, there will often 168 be a separate MS-DOS driver just for the controller. IDE interfaces 169 on sound cards usually fall into this category. Such configurations 170 can often be made to work by first booting MS-DOS, loading the 171 appropriate drivers, and then warm-booting linux (without powering 172 off). This can be automated using loadlin in the MS-DOS autoexec. 173 174If you always get timeout errors, interrupts from the drive are probably 175not making it to the host. Check how you have the hardware jumpered 176and make sure it matches what the driver expects (see the configuration 177instructions above). If you have a PCI system, also check the BIOS 178setup; I've had one report of a system which was shipped with IRQ 15 179disabled by the BIOS. 180 181The kernel is able to execute binaries directly off of the cdrom, 182provided it is mounted with the default block size of 1024 (as above). 183 184Please pass on any feedback on any of this stuff to the maintainer, 185whose address can be found in linux/MAINTAINERS. 186 187Note that if BOTH hd.c and ide.c are configured into the kernel, 188hd.c will normally be allowed to control the primary IDE interface. 189This is useful for older hardware that may be incompatible with ide.c, 190and still allows newer hardware to run on the 2nd/3rd/4th IDE ports 191under control of ide.c. To have ide.c also "take over" the primary 192IDE port in this situation, use the "command line" parameter: ide0=0x1f0 193 194The IDE driver is modularized. The high level disk/CD-ROM/tape/floppy 195drivers can always be compiled as loadable modules, the chipset drivers 196can only be compiled into the kernel, and the core code (ide.c) can be 197compiled as a loadable module provided no chipset support is needed. 198 199When using ide.c as a module in combination with kmod, add: 200 201 alias block-major-3 ide-probe 202 203to /etc/modprobe.conf. 204 205When ide.c is used as a module, you can pass command line parameters to the 206driver using the "options=" keyword to insmod, while replacing any ',' with 207';'. For example: 208 209 insmod ide.o options="ide0=serialize ide1=serialize ide2=0x1e8;0x3ee;11" 210 211 212================================================================================ 213 214Summary of ide driver parameters for kernel command line 215-------------------------------------------------------- 216 217 "hdx=" is recognized for all "x" from "a" to "h", such as "hdc". 218 219 "idex=" is recognized for all "x" from "0" to "3", such as "ide1". 220 221 "hdx=noprobe" : drive may be present, but do not probe for it 222 223 "hdx=none" : drive is NOT present, ignore cmos and do not probe 224 225 "hdx=nowerr" : ignore the WRERR_STAT bit on this drive 226 227 "hdx=cdrom" : drive is present, and is a cdrom drive 228 229 "hdx=cyl,head,sect" : disk drive is present, with specified geometry 230 231 "hdx=remap" : remap access of sector 0 to sector 1 (for EZDrive) 232 233 "hdx=remap63" : remap the drive: add 63 to all sector numbers 234 (for DM OnTrack) 235 236 "idex=noautotune" : driver will NOT attempt to tune interface speed 237 238 "hdx=autotune" : driver will attempt to tune interface speed 239 to the fastest PIO mode supported, 240 if possible for this drive only. 241 Not fully supported by all chipset types, 242 and quite likely to cause trouble with 243 older/odd IDE drives. 244 245 "hdx=swapdata" : when the drive is a disk, byte swap all data 246 247 "hdx=bswap" : same as above.......... 248 249 "hdx=scsi" : the return of the ide-scsi flag, this is useful for 250 allowing ide-floppy, ide-tape, and ide-cdrom|writers 251 to use ide-scsi emulation on a device specific option. 252 253 "idebus=xx" : inform IDE driver of VESA/PCI bus speed in MHz, 254 where "xx" is between 20 and 66 inclusive, 255 used when tuning chipset PIO modes. 256 For PCI bus, 25 is correct for a P75 system, 257 30 is correct for P90,P120,P180 systems, 258 and 33 is used for P100,P133,P166 systems. 259 If in doubt, use idebus=33 for PCI. 260 As for VLB, it is safest to not specify it. 261 Bigger values are safer than smaller ones. 262 263 "idex=noprobe" : do not attempt to access/use this interface 264 265 "idex=base" : probe for an interface at the addr specified, 266 where "base" is usually 0x1f0 or 0x170 267 and "ctl" is assumed to be "base"+0x206 268 269 "idex=base,ctl" : specify both base and ctl 270 271 "idex=base,ctl,irq" : specify base, ctl, and irq number 272 273 "idex=serialize" : do not overlap operations on idex. Please note 274 that you will have to specify this option for 275 both the respective primary and secondary channel 276 to take effect. 277 278 "idex=four" : four drives on idex and ide(x^1) share same ports 279 280 "idex=reset" : reset interface after probe 281 282 "idex=dma" : automatically configure/use DMA if possible. 283 284 "idex=ata66" : informs the interface that it has an 80c cable 285 for chipsets that are ATA-66 capable, but the 286 ability to bit test for detection is currently 287 unknown. 288 289 "ide=reverse" : formerly called to pci sub-system, but now local. 290 291 "ide=nodma" : disable DMA globally for the IDE subsystem. 292 293The following are valid ONLY on ide0, which usually corresponds 294to the first ATA interface found on the particular host, and the defaults for 295the base,ctl ports must not be altered. 296 297 "ide0=cmd640_vlb" : *REQUIRED* for VLB cards with the CMD640 chip 298 (not for PCI -- automatically detected) 299 300 "ide=doubler" : probe/support IDE doublers on Amiga 301 302There may be more options than shown -- use the source, Luke! 303 304Everything else is rejected with a "BAD OPTION" message. 305 306For legacy IDE VLB host drivers (ali14xx/dtc2278/ht6560b/qd65xx/umc8672) 307you need to explicitly enable probing by using "probe" kernel parameter, 308i.e. to enable probing for ALI M14xx chipsets (ali14xx host driver) use: 309 310* "ali14xx.probe" boot option when ali14xx driver is built-in the kernel 311 312* "probe" module parameter when ali14xx driver is compiled as module 313 ("modprobe ali14xx probe") 314 315================================================================================ 316 317IDE ATAPI streaming tape driver 318------------------------------- 319 320This driver is a part of the Linux ide driver and works in co-operation 321with linux/drivers/block/ide.c. 322 323The driver, in co-operation with ide.c, basically traverses the 324request-list for the block device interface. The character device 325interface, on the other hand, creates new requests, adds them 326to the request-list of the block device, and waits for their completion. 327 328Pipelined operation mode is now supported on both reads and writes. 329 330The block device major and minor numbers are determined from the 331tape's relative position in the ide interfaces, as explained in ide.c. 332 333The character device interface consists of the following devices: 334 335 ht0 major 37, minor 0 first IDE tape, rewind on close. 336 ht1 major 37, minor 1 second IDE tape, rewind on close. 337 ... 338 nht0 major 37, minor 128 first IDE tape, no rewind on close. 339 nht1 major 37, minor 129 second IDE tape, no rewind on close. 340 ... 341 342Run /dev/MAKEDEV to create the above entries. 343 344The general magnetic tape commands compatible interface, as defined by 345include/linux/mtio.h, is accessible through the character device. 346 347General ide driver configuration options, such as the interrupt-unmask 348flag, can be configured by issuing an ioctl to the block device interface, 349as any other ide device. 350 351Our own ide-tape ioctl's can be issued to either the block device or 352the character device interface. 353 354Maximal throughput with minimal bus load will usually be achieved in the 355following scenario: 356 357 1. ide-tape is operating in the pipelined operation mode. 358 2. No buffering is performed by the user backup program. 359 360 361 362================================================================================ 363 364Some Terminology 365---------------- 366IDE = Integrated Drive Electronics, meaning that each drive has a built-in 367controller, which is why an "IDE interface card" is not a "controller card". 368 369ATA = AT (the old IBM 286 computer) Attachment Interface, a draft American 370National Standard for connecting hard drives to PCs. This is the official 371name for "IDE". 372 373The latest standards define some enhancements, known as the ATA-6 spec, 374which grew out of vendor-specific "Enhanced IDE" (EIDE) implementations. 375 376ATAPI = ATA Packet Interface, a new protocol for controlling the drives, 377similar to SCSI protocols, created at the same time as the ATA2 standard. 378ATAPI is currently used for controlling CDROM, TAPE and FLOPPY (ZIP or 379LS120/240) devices, removable R/W cartridges, and for high capacity hard disk 380drives. 381 382mlord@pobox.com 383-- 384 385Wed Apr 17 22:52:44 CEST 2002 edited by Marcin Dalecki, the current 386maintainer. 387 388Wed Aug 20 22:31:29 CEST 2003 updated ide boot options to current ide.c 389comments at 2.6.0-test4 time. Maciej Soltysiak <solt@dns.toxicfilms.tv> 390