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This is the ALPHA version of the ltpc driver.

In order to use it, you will need at least version 1.3.3 of the

netatalk package, and the Apple or Farallon LocalTalk PC card.

There are a number of different LocalTalk cards for the PC; this

driver applies only to the one with the 65c02 processor chip on it.

To include it in the kernel, select the CONFIG_LTPC switch in the

configuration dialog.  You can also compile it as a module.

While the driver will attempt to autoprobe the I/O port address, IRQ

line, and DMA channel of the card, this does not always work.  For

this reason, you should be prepared to supply these parameters

yourself.  (see "Card Configuration" below for how to determine or

change the settings on your card)

When the driver is compiled into the kernel, you can add a line such

as the following to your /etc/lilo.conf:

 append="ltpc=0x240,9,1"

where the parameters (in order) are the port address, IRQ, and DMA

channel.  The second and third values can be omitted, in which case

the driver will try to determine them itself.

If you load the driver as a module, you can pass the parameters "io=",

"irq=", and "dma=" on the command line with insmod or modprobe, or add

them as options in /etc/modules.conf:

 alias lt0 ltpc # autoload the module when the interface is configured

 options ltpc io=0x240 irq=9 dma=1

Before starting up the netatalk demons (perhaps in rc.local), you

need to add a line such as:

 /sbin/ifconfig lt0 127.0.0.42

The address is unimportant - however, the card needs to be configured

with ifconfig so that Netatalk can find it.

The appropriate netatalk configuration depends on whether you are

attached to a network that includes AppleTalk routers or not.  If,

like me, you are simply connecting to your home Macintoshes and

printers, you need to set up netatalk to "seed".  The way I do this

is to have the lines

 dummy -seed -phase 2 -net 2000 -addr 2000.26 -zone "1033"

 lt0 -seed -phase 1 -net 1033 -addr 1033.27 -zone "1033"

in my atalkd.conf.  What is going on here is that I need to fool

netatalk into thinking that there are two AppleTalk interfaces

present; otherwise, it refuses to seed.  This is a hack, and a more

permanent solution would be to alter the netatalk code.  Also, make

sure you have the correct name for the dummy interface - If it's

compiled as a module, you will need to refer to it as "dummy0" or some

such.

If you are attached to an extended AppleTalk network, with routers on

it, then you don't need to fool around with this -- the appropriate

line in atalkd.conf is

 lt0 -phase 1

--------------------------------------

Card Configuration:

The interrupts and so forth are configured via the dipswitch on the

board.  Set the switches so as not to conflict with other hardware.

       Interrupts -- set at most one.  If none are set, the driver uses

       polled mode.  Because the card was developed in the XT era, the

       original documentation refers to IRQ2.  Since you'll be running

       this on an AT (or later) class machine, that really means IRQ9.

       SW1     IRQ 4

       SW2     IRQ 3

       SW3     IRQ 9 (2 in original card documentation only applies to XT)

       DMA -- choose DMA 1 or 3, and set both corresponding switches.

       SW4     DMA 3

       SW5     DMA 1

       SW6     DMA 3

       SW7     DMA 1

       I/O address -- choose one.

       SW8     220 / 240

--------------------------------------

IP:

Yes, it is possible to do IP over LocalTalk.  However, you can't just

treat the LocalTalk device like an ordinary Ethernet device, even if

that's what it looks like to Netatalk.

Instead, you follow the same procedure as for doing IP in EtherTalk.

See Documentation/networking/ipddp.txt for more information about the

kernel driver and userspace tools needed.

--------------------------------------

BUGS:

IRQ autoprobing often doesn't work on a cold boot.  To get around

this, either compile the driver as a module, or pass the parameters

for the card to the kernel as described above.

Also, as usual, autoprobing is not recommended when you use the driver

as a module. (though it usually works at boot time, at least)

Polled mode is *really* slow sometimes, but this seems to depend on

the configuration of the network.

It may theoretically be possible to use two LTPC cards in the same

machine, but this is unsupported, so if you really want to do this,

you'll probably have to hack the initialization code a bit.

______________________________________

THANKS:

        Thanks to Alan Cox for helpful discussions early on in this

work, and to Denis Hainsworth for doing the bleeding-edge testing.

-- Bradford Johnson 

-- Updated 11/09/1998 by David Huggins-Daines