isdn: remove isdn4linux

With all isdn4linux hardware drivers gone, this is only a wrapper around
CAPI to support old user space. However, from looking at the mailing
list, it seems that the last time anyone asked about it was in 2014,
when the upgrade from a linux-2.4 installation failed, and mISDN was
suggested as a replacement.

The largest public ISDN network (Deutsche Telekom) was supposed to be
shut down 2018, which must have drastically reduced the number of legacy
installations.

When we last discussed removing i4l in 2016, Karsten Keil suggested
revisiting this in 2018. I guess this is overdue.

Link: http://listserv.isdn4linux.de/pipermail/isdn4linux/2014-October/006165.html
Link: https://patchwork.kernel.org/patch/8484861/#17900371
Link: https://listserv.isdn4linux.de/pipermail/isdn4linux/2019-April/thread.html
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 0 insertions, 127 deletions

diff --git a/Documentation/isdn/README.diversion b/Documentation/isdn/README.diversion
deleted file mode 100644
index bddcd5fb86ff..000000000000
--- a/Documentation/isdn/README.diversion
+++ /dev/null
@@ -1,127 +0,0 @@
-The isdn diversion services are a supporting module working together with
-the isdn4linux and the HiSax module for passive cards. 
-Active cards, TAs and cards using a own or other driver than the HiSax 
-module need to be adapted to the HL<->LL interface described in a separate 
-document. The diversion services may be used with all cards supported by 
-the HiSax driver.
-The diversion kernel interface and controlling tool divertctrl were written
-by Werner Cornelius (werner@isdn4linux.de or werner@titro.de) under the
-GNU General Public License.
-
-    This program is free software; you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation; either version 2 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-
-Table of contents
-=================
-
-1. Features of the i4l diversion services 
-   (Or what can the i4l diversion services do for me)
-
-2. Required hard- and software
-
-3. Compiling, installing and loading/unloading the module  
-   Tracing calling and diversion information 
-
-4. Tracing calling and diversion information
- 
-5. Format of the divert device ASCII output
- 
-
-1. Features of the i4l diversion services 
-   (Or what can the i4l diversion services do for me)
-
-   The i4l diversion services offers call forwarding and logging normally 
-   only supported by isdn phones. Incoming calls may be diverted 
-   unconditionally (CFU), when not reachable (CFNR) or on busy condition 
-   (CFB). 
-   The diversions may be invoked statically in the providers exchange
-   as normally done by isdn phones. In this case all incoming calls
-   with a special (or all) service identifiers are forwarded if the 
-   forwarding reason is met. Activated static services may also be 
-   interrogated (queried).
-   The i4l diversion services additionally offers a dynamic version of
-   call forwarding which is not preprogrammed inside the providers exchange
-   but dynamically activated by i4l.
-   In this case all incoming calls are checked by rules that may be
-   compared to the mechanism of ipfwadm or ipchains. If a given rule matches
-   the checking process is finished and the rule matching will be applied
-   to the call.
-   The rules include primary and secondary service identifiers, called 
-   number and subaddress, callers number and subaddress and whether the rule
-   matches to all filtered calls or only those when all B-channel resources
-   are exhausted.
-   Actions that may be invoked by a rule are ignore, proceed, reject, 
-   direct divert or delayed divert of a call.
-   All incoming calls matching a rule except the ignore rule a reported and
-   logged as ASCII via the proc filesystem (/proc/net/isdn/divert). If proceed
-   is selected the call will be held in a proceeding state (without ringing)
-   for a certain amount of time to let an external program or client decide
-   how to handle the call. 
-            
-
-2. Required hard- and software
-   
-   For using the i4l diversion services the isdn line must be of a EURO/DSS1
-   type. Additionally the i4l services only work together with the HiSax 
-   driver for passive isdn cards. All HiSax supported cards may be used for
-   the diversion purposes.
-   The static diversion services require the provider having static services
-   CFU, CFNR, CFB activated on an MSN-line. The static services may not be 
-   used on a point-to-point connection. Further the static services are only
-   available in some countries (for example germany). Countries requiring the 
-   keypad protocol for activating static diversions (like the netherlands) are
-   not supported but may use the tty devices for this purpose.
-   The dynamic diversion services may be used in all countries if the provider
-   enables the feature CF (call forwarding). This should work on both MSN- and
-   point-to-point lines.
-   To add and delete rules the additional divertctrl program is needed. This
-   program is part of the isdn4kutils package.   
-
-3. Compiling, installing and loading/unloading the module  
-   Tracing calling and diversion information 
-
-
-   To compile the i4l code with diversion support you need to say yes to the 
-   DSS1 diversion services when selecting the i4l options in the kernel 
-   config (menuconfig or config).
-   After having properly activated a make modules and make modules_install all
-   required modules will be correctly installed in the needed modules dirs.
-   As the diversion services are currently not included in the scripts of most
-   standard distributions you will have to add a "insmod dss1_divert" after
-   having loaded the global isdn module.
-   The module can be loaded without any command line parameters.
-   If the module is actually loaded and active may be checked with a 
-   "cat /proc/modules" or "ls /proc/net/isdn/divert". The divert file is 
-   dynamically created by the diversion module and removed when the module is
-   unloaded.
-
-
-4. Tracing calling and diversion information
- 
-   You also may put a "cat /proc/net/isdn/divert" in the background with the
-   output redirected to a file. Then all actions of the module are logged.
-   The divert file in the proc system may be opened more than once, so in 
-   conjunction with inetd and a small remote client on other machines inside
-   your network incoming calls and reactions by the module may be shown on 
-   every listening machine. 
-   If a call is reported as proceeding an external program or client may 
-   specify during a certain amount of time (normally 4 to 10 seconds) what
-   to do with that call.      
-   To unload the module all open files to the device in the proc system must
-   be closed. Otherwise the module (and isdn.o) may not be unloaded. 
-
-5. Format of the divert device ASCII output
- 
-   To be done later
-