.\"	$OpenBSD: pciide.4,v 1.17 2001/09/29 02:58:29 jason Exp $
.\"	$NetBSD: pciide.4,v 1.8 1999/03/16 01:19:17 garbled Exp $
.\"
.\" Copyright (c) 1998 Manuel Bouyer.
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.Dd October 15, 1998
.Dt PCIIDE 4
.Os
.Sh NAME
.Nm pciide
.Nd PCI IDE controller driver
.Sh SYNOPSIS
.Cd "pciide* at pci ? dev ? function ? flags 0x0000"
.Cd "options PCIIDE_CMD064x_DISABLE"
.Sh DESCRIPTION
The
.Nm
driver supports the PCI IDE controllers as specified in the
"PCI IDE controller specification, revision 1.0" draft, and provides the core
functions for the
.Xr wd 4
and
.Xr atapiscsi 4
drivers. This driver includes specific, enhanced support for the CMD Tech
PCI0640 controller and IDE DMA/UltraDMA support for the following PCI IDE
controllers:
.Pp
.Bl -item -compact -offset indent
.It
Acard ATP850, ATP860
.It
Acer Labs M5229
.It
Advanced Micro Devices AMD-756, AMD-766
.It
CMD Tech PCI0640, PCI0643, PCI0646, PCI0648, PCI0649
.It
Contaq Microsystems/Cypress CY82C693
.It
HighPoint HPT366, HPT370
.It
Intel PIIX, PIIX3, and PIIX4
.It
Intel 82801 (ICH/ICH0/ICH2)
.It
National Semiconductor PC87415
.It
OPTi 82c621
.It
Promise PDC20246, PDC20262, PDC20265, PDC20267
.It
Silicon Integrated System 5513 (5597/5598)
.It
VIA Technologies VT82C586/A/B, VT82C596A/B, VT82C686A/B
.El
.Pp
Some of these controllers are only available in multifunction PCI chips.
.Pp
The
.Li 0x0001
flag forces the
.Nm
driver to use DMA when there is no explicit DMA mode setting support for
the controller but DMA is present.
If the BIOS didn't configure the controller properly, this can
cause a machine hang.
.Sh SEE ALSO
.Xr atapiscsi 4 ,
.Xr intro 4 ,
.Xr scsi 4 ,
.Xr wd 4 ,
.Xr wdc 4
.Sh BUGS
There's no way to know reliably if a PCI064x controller is enabled or not.
If the driver finds a PCI064x, it will assume it is enabled unless
.Dv PCIIDE_CMD064x_DISABLE
is specified in the kernel config file.
This will be a problem only if the controller has been disabled in the BIOS
and another controller has been installed which uses the ISA legacy I/O ports
and interrupts.
.Pp
The OPTi controller code is disabled by default because the driver
does not yet work around all bugs in current chipsets.
.Pp
For proper operation of UltraDMA 3
.Pq 44 MB/sec ,
4
.Pq 66 MB/sec ,
or 5
.Pq 100 MB/sec ,
a 40-pin, 80-conductor cable must be used.
On some controllers, the pciide driver can probe the chip and see if it
detects that an 80-conductor or 40-conductor cable was used.
If not, it will down-grade to UltraDMA 2 mode.
On other controllers, no such capability exists, and the driver assumes
you are using an 80-conductor cable.
If you are getting errors about
corrupted data, check to make sure you are using the correct cable.
An 80-conductor cable is recommended for any IDE installation, not just
ones using faster UltraDMA modes, because it will decrease electrical
noise and increase data reliability.
.Pp
The AMD756 chip revision D2 has a bug affecting DMA (but not Ultra-DMA)
modes.  The workaround documented by AMD is to not use DMA on any drive which
does not support Ultra-DMA modes.  This does not appear to be necessary on all
drives, the PCIIDE_AMD756_ENABLEDMA option can be used to force multiword DMA
on the buggy revisions.  Multiword DMA can eventually be disabled on a
per-drive basis with config flags, see
.Xr wd 4 .
The bug, if triggered, will cause a total system hang.
.Pp
The timings used for the PIO and DMA modes for controllers listed above
are for a PCI bus running at 30 or 33 MHz.
These timings will work on a slower bus,
but they may cause errors on an over-clocked bus.