WDC(4) BSD Programmer's Manual WDC(4)NAMEwdc - PC Compatible Hard Disk Controller Driver
SYNOPSIS
wdc0 at isa? port 0x1f0
wdc0 at pciwdc0 port 0x1f0
wdc* at pciwdc? port ?
DESCRIPTION
This driver manages the resources of a PC compatible disk controller. It
provides a kernel interface to child drivers (such as wd and wdpi) so
that they may share the controller resources. Up to two child devices
may be present. It uses a block of 8 I/O ports which must be aligned on
an 8 port boundary. Traditional ISA controllers are located "at isa?",
and a base port must be specified. The values "IO_WD1" and "IO_WD2" (in-
cluding the quotes) can be used for the standard primary and secondary
addresses.
PCI-based controllers on a system mainboard or a PCI expansion card can
be configured via a pciwdc device (see pciwdc(4)), allowing DMA to be
used for attached disks. A specific pciwdc parent may be specified, usu-
ally with a specific port address as shown in the second synopsis line,
in order to force the unit numbering. Alternatively, the pciwdc unit and
port address can be wild-carded, and a configuration like the third syn-
opsis example will match any number of wdc devices. This is usually used
for PCI cards that do not use the primary or secondary addresses.
The hardware interrupt level is detected during autoconfiguration or, for
PCI cards not using the standard primary or secondary locations, via the
PCI configuration set by the BIOS. During the probe sequence a check is
made for PCMCIA style controllers using an alternate register layout.
This check is only run if the controller isn't found using the standard
layout and can can be inhibited by setting the boot flags to 1 ("-dev
wdc0 flags=1" from the boot command line or in /etc/boot.default).
This driver is required if either the wd or the wdpi drivers are to be
used.
SEE ALSOpciwdc(4), wd(4), wdpi(4)BSDI BSD/OS May 3, 2001 1
