mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-19 10:53:58 +00:00
159 lines
3.9 KiB
Groff
159 lines
3.9 KiB
Groff
.\" Copyright (c) 2003 Poul-Henning Kamp <phk@FreeBSD.org>
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd November 23, 2003
|
|
.Dt CPU_ELAN 4 i386
|
|
.Os
|
|
.Sh NAME
|
|
.Nm CPU_ELAN
|
|
.Nd AMD Elan 520 CPU support
|
|
.Sh SYNOPSIS
|
|
.Cd "options CPU_ELAN"
|
|
.Cd "options CPU_ELAN_PPS"
|
|
.Cd "options CPU_ELAN_XTAL"
|
|
.Bl -item -compact
|
|
.It
|
|
.Va machdep.elan_gpio_config
|
|
.It
|
|
.Va machdep.elan_freq
|
|
.El
|
|
.Cd "options CPU_SOEKRIS"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Cd "options CPU_ELAN"
|
|
enables support for the AMD Elan 520 CPU.
|
|
.Pp
|
|
A device
|
|
.Pa /dev/elan-mmcr
|
|
exports the MMCR register bank to userland
|
|
using
|
|
.Xr mmap 2 .
|
|
.Pp
|
|
The
|
|
.Tn i8254
|
|
timer will be adjusted to the slightly unorthodox
|
|
frequency 1189161 Hz (32768 * 45 * 25 / 31) employed by the Elan.
|
|
.Pp
|
|
A timecounter named
|
|
.Dq Li ELAN
|
|
is implemented using the general purpose timer 2,
|
|
but it will not be usable unless HZ is configured at 150 or higher.
|
|
This timecounter is much better than the
|
|
.Dq Li i8254
|
|
timecounter and should be
|
|
used at all times.
|
|
.Pp
|
|
The
|
|
.Va machdep.elan_gpio_config
|
|
.Xr sysctl 8
|
|
variable
|
|
enables configuration of the GPIO pins of the CPU.
|
|
The string must be exactly 32 characters long.
|
|
A
|
|
.Ql -
|
|
means the GPIO is unavailable.
|
|
A
|
|
.Ql l
|
|
(lower-case ell) configures a
|
|
.Xr led 4
|
|
device (active low).
|
|
A
|
|
.Ql L
|
|
configures a
|
|
.Xr led 4
|
|
device (active high).
|
|
A
|
|
.Ql \&.
|
|
means no configuration for this GPIO.
|
|
These
|
|
.Xr led 4
|
|
devices will be named
|
|
.Pa /dev/led/gpio%d .
|
|
For meaning of
|
|
.Ql P ,
|
|
.Ql e
|
|
and
|
|
.Ql E ,
|
|
see under
|
|
.Cd "options CPU_ELAN_PPS" .
|
|
.Pp
|
|
The
|
|
.Cd "options CPU_ELAN_XTAL"
|
|
and the
|
|
.Va machdep.elan_freq
|
|
.Xr sysctl 8
|
|
variable
|
|
can be used to set the CPU clock crystal frequency in Hz.
|
|
The default is 33333333 Hz.
|
|
.Pp
|
|
The
|
|
.Cd "options CPU_ELAN_PPS"
|
|
enables precision timestamping using the RFC2783 PPS-API via the
|
|
.Pa /dev/elan-mmcr
|
|
device.
|
|
The resolution will be approximately 125 nsec
|
|
and the precision \(+- 125 nsec.
|
|
(For 125 nsec read
|
|
.Dq "4 / CPU clock crystal frequency" . )
|
|
.Pp
|
|
The input signal must be connected to the TMR1IN pin and
|
|
a GPIO pin.
|
|
The GPIO pin must be configured with a
|
|
.Ql P
|
|
in
|
|
.Va machdep.elan_gpio_config .
|
|
.Pp
|
|
In addition, one GPIO pin can be configured with either
|
|
.Ql e
|
|
(active low)
|
|
or
|
|
.Ql E
|
|
(active high) to become a
|
|
.Dq echo
|
|
output of the input signal.
|
|
Please notice that this signal is not suitable for calibration.
|
|
.Pp
|
|
If the
|
|
.Cd "options CPU_SOEKRIS"
|
|
is given, the support will additionally be tailored to the
|
|
Soekris Engineering 45xx series of embedded computers.
|
|
The
|
|
.Dq error
|
|
led will be configured (as
|
|
.Pa /dev/led/error )
|
|
and the GPIO pins which are not
|
|
available will be disabled.
|
|
.Sh SEE ALSO
|
|
.Xr led 4 ,
|
|
.Xr sysctl 8
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
code first appeared in
|
|
.Fx 4.7 .
|
|
.Sh AUTHORS
|
|
.An "Poul-Henning Kamp" Aq phk@FreeBSD.org
|