NAME¶
cy
—
Cyclades Cyclom-Y serial driver
SYNOPSIS¶
For one ISA card:
device cy
In
/boot/device.hints:
hint.cy.0.at="isa"
hint.cy.0.irq="10"
hint.cy.0.maddr="0xd4000"
hint.cy.0.msize="0x2000"
For two ISA cards:
device cy
In
/boot/device.hints:
hint.cy.0.at="isa"
hint.cy.0.irq="10"
hint.cy.0.maddr="0xd4000"
hint.cy.0.msize="0x2000"
hint.cy.1.at="isa"
hint.cy.1.irq="11"
hint.cy.1.maddr="0xd6000"
hint.cy.1.msize="0x2000"
For PCI cards:
device cy
options CY_PCI_FASTINTR
No lines are required in
/boot/device.hints
for PCI cards.
Minor numbering:
0b MMMMMMMMMMMMMMMMxxxxxxxxOLIMMMMM
callOut
Lock
Initial
MMMMMMMMMMMMMMMM MMMMMMinor
DESCRIPTION¶
The
cy
driver provides support for Cirrus
Logic CD1400-based EIA RS-232C (CCITT V.24) communications interfaces (ports)
on Cyclades Cyclom-Y boards. Each CD1400 provides 4 ports. Cyclom-Y boards
with various numbers of CD1400's are available. This driver supports up to 8
CD1400's (32 ports) per board.
Input and output for each line may set independently to the following speeds:
50, 75, 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 4800, 9600, 19200, 38400,
57600, or 115200 bps. Other speeds of up to 150000 are supported by the
termios interface but not by the sgttyb compatibility interface. The CD1400 is
not fast enough to handle speeds above 115200 bps effectively. It can transmit
on a single line at slightly more than 115200 bps, but when 4 lines are active
in both directions its limit is about 90000 bps on each line.
Serial ports controlled by the
cy
driver can
be used for both `callin' and `callout'. For each port there is a callin
device and a callout device. The minor number of the callout device is 128
higher than that of the corresponding callin port. The callin device is
general purpose. Processes opening it normally wait for carrier and for the
callout device to become inactive. The callout device is used to steal the
port from processes waiting for carrier on the callin device. Processes
opening it do not wait for carrier and put any processes waiting for carrier
on the callin device into a deeper sleep so that they do not conflict with the
callout session. The callout device is abused for handling programs that are
supposed to work on general ports and need to open the port without waiting
but are too stupid to do so.
The
cy
driver also supports an initial-state
and a lock-state control device for each of the callin and the callout
"data" devices. The minor number of the initial-state device is 32
higher than that of the corresponding data device. The minor number of the
lock-state device is 64 higher than that of the corresponding data device. The
termios settings of a data device are copied from those of the corresponding
initial-state device on first opens and are not inherited from previous opens.
Use
stty(1) in the normal way on the
initial-state devices to program initial termios states suitable for your
setup.
The lock termios state acts as flags to disable changing the termios state.
E.g., to lock a flag variable such as CRTSCTS, use
stty crtscts on the lock-state device. Speeds and
special characters may be locked by setting the corresponding value in the
lock-state device to any nonzero value.
Correct programs talking to correctly wired external devices work with almost
arbitrary initial states and almost no locking, but other setups may benefit
from changing some of the default initial state and locking the state. In
particular, the initial states for non (POSIX) standard flags should be set to
suit the devices attached and may need to be locked to prevent buggy programs
from changing them. E.g., CRTSCTS should be locked on for devices that support
RTS/CTS handshaking at all times and off for devices that do not support it at
all. CLOCAL should be locked on for devices that do not support carrier. HUPCL
may be locked off if you do not want to hang up for some reason. In general,
very bad things happen if something is locked to the wrong state, and things
should not be locked for devices that support more than one setting. The
CLOCAL flag on callin ports should be locked off for logins to avoid certain
security holes, but this needs to be done by getty if the callin port is used
for anything else.
Kernel Configuration Options¶
The
CY_PCI_FASTINTR option should be used to avoid
suboptimal interrupt handling for PCI Cyclades boards. The PCI BIOS must be
configured with the
cy
interrupt not shared
with any other active device for this option to work. This option is not the
default because it is currently harmful in certain cases where it does not
work.
FILES¶
- /dev/ttyc??
- for callin ports
- /dev/ttyic??
-
- /dev/ttylc??
- corresponding callin initial-state and lock-state devices
- /dev/cuac??
- for callout ports
- /dev/cuaic??
-
- /dev/cualc??
- corresponding callout initial-state and lock-state devices
- /etc/rc.serial
- examples of setting the initial-state and lock-state devices
The first question mark in these device names is short for the card number (a
decimal number between 0 and 65535 inclusive). The second question mark is
short for the port number (a letter in the range [0-9a-v]).
DIAGNOSTICS¶
- cy%d: silo overflow.
- Problem in the interrupt handler.
- cy%d: interrupt-level buffer overflow.
- Problem in the bottom half of the driver.
- cy%d: tty-level buffer overflow.
- Problem in the application. Input has arrived faster than the given module
could process it and some has been lost.
SEE ALSO¶
stty(1),
termios(4),
tty(4),
comcontrol(8),
pstat(8)
HISTORY¶
The
cy
driver is derived from the
sio
driver and the
NetBSD cy
driver
and is currently under development.
BUGS¶
Serial consoles are not implemented.