SI(4)

NAME
si - Driver for Specialix International SI/XIO 8-32 port intelligent serial card.

SYNOPSIS
device si0 at isa? tty irq 12 iomem 0xd0000 vector siintr

DESCRIPTION
The Specialix SI and XIO hardware makes up an 8 to 32 port RS-232 serial multiplexor.

This driver was ported and tested on an ISA bus machine, and has rudimentry support for operation on an EISA bus system as well, but as of this time the EISA version has not been tested by the Author - it may or may not work.

The system uses two components.. A "Host adapter", which is plugged into an ISA/EISA slot and provides intelligence and buffering/processing capabilities, as well as an external bus in the form of a 50 pin cable.

On this cable, "modules" are connected. The "SI" module comes in a 4 and 8 port version, and has simple UARTS. The "XIO" module comes only in an 8 port version, and has two powerful RISC-like UARTS as well.

The host adapter polls and transfers data between the modules and the main Operating system. The Host adapter provides a 256 byte transmit and 256 byte receive FIFO for each of the 32 ports that it can maintain.

The XIO module panels can operate each of their 8 ports at 115,200 baud, while the SI version can run at 57,600 baud.

The host adapter uses a shared memory block in the traditional ISA bus "hole" betweem 0xA0000 and 0xEFFFF. The adapter can be configured outside range, but requires the memory range to be explicitly non-cached. The driver does not yet support this mode of operation.

The adapter can use Irq's 11, 12 or 15. It is rumoured that the ISA adapter cards provide their own tri-state drivers and pullups, and may be able to share an IRQ between all SI/XIO host cards. This has not been tested, and the driver does not support this mode of operation. The actual IRQ used is soft-configured onto the host card at boot time, but automatic selection of a free IRQ is not yet implemented in the FreeBSD version.

The si device driver may have some of it's configuration settings changed at run-time with the sicontrol(8) utility.

The si device driver also responds to the comcontrol(8) utility for configuring drain-on-close timeouts.

An open on a /dev device node controlled by the si driver obeys the same semantics as the sio(4) driver. It fully supports the usual semantics of the cua ports, and the "initial termios" and "locked termios" settings. In summary, an open on a tty port will block until DCD is raised, unless O_NONBLOCK is specified. CLOCAL is honored. An open on a cua port will always succeed, but DCD transitions will be honored after DCD rises for the first time. by the si driver obeys the same semantics as the sio(4) driver. It fully supports the usual semantics of the cua ports, and the "initial termios" and "locked termios" settings. In summary, an open on a tty port will block until DCD is raised, unless O_NONBLOCK is specified. CLOCAL is honored. An open on a cua port will always succeed, but DCD transitions will be honored after DCD rises for the first time.

Normally, up to four SI/XIO host cards may be controlled by the si driver, but due to the lack of available interrupts that the card can be configured to use, only three may be presently used. Polling operation is not currently implemented, although it is a standard mode of operation for Specialix shipped drivers. Once this is implemented, all four cards may be used.

The lowest 5 bits of the minor device number are used to select the port number on the mudule cluster. si driver, but due to the lack of available interrupts that the card can be configured to use, only three may be presently used. Polling operation is not currently implemented, although it is a standard mode of operation for Specialix shipped drivers. Once this is implemented, all four cards may be used.

The lowest 5 bits of the minor device number are used to select the port number on the mudule cluster. The next 2 bits select which of 4 host adapter cards. This allows a maximum of 128 ports on this driver.

Bit 7 is used to differentiate a tty/dialin port (bit 7=0) and a cua/callout port (bit 7=1).

Bit 8 through 15 (on FreeBSD) are unavailable as they are a shadow of the major device number.

If bit 16 is a 1, the device node is referring to the "initial state" device. This "initial state" is used to prime the termios(4) settings of the device when it is initially opened. If bit 17 is a 1, the device node is referring to the "locked state" device. The "locked state" is used to prevent the termios(4) settings from being changed.

To manipulate the initial/locked settings, the stty(1) command is useful. When setting the "locked" variables, enabling the mode on the lock device will lock the termios mode, while disabling the mode will unlock it.

FILES
/dev/si_control
    global driver control file for sicontrol(8)
/dev/ttyA*
    terminal/dialin ports
/dev/cuaA*
    dialout ports
/dev/ttyiA*
    initial termios state devices
/dev/ttylA*
    locked termios state devices

SEE ALSO
stty(1), termios(4), tty(4), sio(4), sicontrol(8), comcontrol(8).

HISTORY
This driver is loosely based on driver code originating at Specialix, which was ported to run on BSDI by Andy Rutter <andy@specialix.co.uk>. The System V driver source is/was available by ftp from ftp.specialix.co.uk.

This driver is not supported by Specialix International.

AUTHORS
Peter Wemm <peter@freebsd.org> obtained the code from Andy Rutter and ported it to FreeBSD, with a large amount of invalueable assistance from Bruce Evans <bde@zeta.org.au>

Man page by Peter Wemm.

BUGS
The EISA support is untested.

The interrupt tuning rate is not believed to be optimal at this time for maximum efficiency.

Receiver tty buffer flushing is not yet enabled, like many other drivers.

POLL mode is not implemented yet.

Operation outside the traditional ISA "hole" is not yet supported, although it should work if the test is removed from the probe routine.