1.. SPDX-License-Identifier: GPL-2.0
2
3===========
4LTPC Driver
5===========
6
7This is the ALPHA version of the ltpc driver.
8
9In order to use it, you will need at least version 1.3.3 of the
10netatalk package, and the Apple or Farallon LocalTalk PC card.
11There are a number of different LocalTalk cards for the PC; this
12driver applies only to the one with the 65c02 processor chip on it.
13
14To include it in the kernel, select the CONFIG_LTPC switch in the
15configuration dialog.  You can also compile it as a module.
16
17While the driver will attempt to autoprobe the I/O port address, IRQ
18line, and DMA channel of the card, this does not always work.  For
19this reason, you should be prepared to supply these parameters
20yourself.  (see "Card Configuration" below for how to determine or
21change the settings on your card)
22
23When the driver is compiled into the kernel, you can add a line such
24as the following to your /etc/lilo.conf::
25
26 append="ltpc=0x240,9,1"
27
28where the parameters (in order) are the port address, IRQ, and DMA
29channel.  The second and third values can be omitted, in which case
30the driver will try to determine them itself.
31
32If you load the driver as a module, you can pass the parameters "io=",
33"irq=", and "dma=" on the command line with insmod or modprobe, or add
34them as options in a configuration file in /etc/modprobe.d/ directory::
35
36 alias lt0 ltpc # autoload the module when the interface is configured
37 options ltpc io=0x240 irq=9 dma=1
38
39Before starting up the netatalk demons (perhaps in rc.local), you
40need to add a line such as::
41
42 /sbin/ifconfig lt0 127.0.0.42
43
44The address is unimportant - however, the card needs to be configured
45with ifconfig so that Netatalk can find it.
46
47The appropriate netatalk configuration depends on whether you are
48attached to a network that includes AppleTalk routers or not.  If,
49like me, you are simply connecting to your home Macintoshes and
50printers, you need to set up netatalk to "seed".  The way I do this
51is to have the lines::
52
53 dummy -seed -phase 2 -net 2000 -addr 2000.26 -zone "1033"
54 lt0 -seed -phase 1 -net 1033 -addr 1033.27 -zone "1033"
55
56in my atalkd.conf.  What is going on here is that I need to fool
57netatalk into thinking that there are two AppleTalk interfaces
58present; otherwise, it refuses to seed.  This is a hack, and a more
59permanent solution would be to alter the netatalk code.  Also, make
60sure you have the correct name for the dummy interface - If it's
61compiled as a module, you will need to refer to it as "dummy0" or some
62such.
63
64If you are attached to an extended AppleTalk network, with routers on
65it, then you don't need to fool around with this -- the appropriate
66line in atalkd.conf is::
67
68 lt0 -phase 1
69
70
71Card Configuration
72==================
73
74The interrupts and so forth are configured via the dipswitch on the
75board.  Set the switches so as not to conflict with other hardware.
76
77       Interrupts -- set at most one.  If none are set, the driver uses
78       polled mode.  Because the card was developed in the XT era, the
79       original documentation refers to IRQ2.  Since you'll be running
80       this on an AT (or later) class machine, that really means IRQ9.
81
82       ===     ===========================================================
83       SW1     IRQ 4
84       SW2     IRQ 3
85       SW3     IRQ 9 (2 in original card documentation only applies to XT)
86       ===     ===========================================================
87
88
89       DMA -- choose DMA 1 or 3, and set both corresponding switches.
90
91       ===     =====
92       SW4     DMA 3
93       SW5     DMA 1
94       SW6     DMA 3
95       SW7     DMA 1
96       ===     =====
97
98
99       I/O address -- choose one.
100
101       ===     =========
102       SW8     220 / 240
103       ===     =========
104
105
106IP
107==
108
109Yes, it is possible to do IP over LocalTalk.  However, you can't just
110treat the LocalTalk device like an ordinary Ethernet device, even if
111that's what it looks like to Netatalk.
112
113Instead, you follow the same procedure as for doing IP in EtherTalk.
114See Documentation/networking/ipddp.rst for more information about the
115kernel driver and userspace tools needed.
116
117
118Bugs
119====
120
121IRQ autoprobing often doesn't work on a cold boot.  To get around
122this, either compile the driver as a module, or pass the parameters
123for the card to the kernel as described above.
124
125Also, as usual, autoprobing is not recommended when you use the driver
126as a module. (though it usually works at boot time, at least)
127
128Polled mode is *really* slow sometimes, but this seems to depend on
129the configuration of the network.
130
131It may theoretically be possible to use two LTPC cards in the same
132machine, but this is unsupported, so if you really want to do this,
133you'll probably have to hack the initialization code a bit.
134
135
136Thanks
137======
138
139Thanks to Alan Cox for helpful discussions early on in this
140work, and to Denis Hainsworth for doing the bleeding-edge testing.
141
142Bradford Johnson <bradford@math.umn.edu>
143
144Updated 11/09/1998 by David Huggins-Daines <dhd@debian.org>
145