tty: remove broken r3964 line discipline

Noone stepped up in the past two years since it was marked as BROKEN by
commit c7084edc3f6d (tty: mark Siemens R3964 line discipline as BROKEN).
Remove the line discipline for good.

Three remarks:
* we remove also the uapi header (as noone is able to use that interface
  anyway)
* we do *not* remove the N_R3964 constant definition from tty.h, so it
  remains reserved.
* in_interrupt() check is now removed from vt's con_put_char. Noone else
  calls tty_operations::put_char from interrupt context.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210505091928.22010-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 0 insertions, 99 deletions

diff --git a/include/uapi/linux/n_r3964.h b/include/uapi/linux/n_r3964.h
deleted file mode 100644
index 6bbd18520f30..000000000000
--- a/include/uapi/linux/n_r3964.h
+++ /dev/null
@@ -1,99 +0,0 @@
-/* SPDX-License-Identifier: GPL-1.0+ WITH Linux-syscall-note */
-/* r3964 linediscipline for linux
- *
- * -----------------------------------------------------------
- * Copyright by
- * Philips Automation Projects
- * Kassel (Germany)
- * -----------------------------------------------------------
- * This software may be used and distributed according to the terms of
- * the GNU General Public License, incorporated herein by reference.
- *
- * Author:
- * L. Haag
- *
- * $Log: r3964.h,v $
- * Revision 1.4  2005/12/21 19:54:24  Kurt Huwig <kurt huwig de>
- * Fixed HZ usage on 2.6 kernels
- * Removed unnecessary include
- *
- * Revision 1.3  2001/03/18 13:02:24  dwmw2
- * Fix timer usage, use spinlocks properly.
- *
- * Revision 1.2  2001/03/18 12:53:15  dwmw2
- * Merge changes in 2.4.2
- *
- * Revision 1.1.1.1  1998/10/13 16:43:14  dwmw2
- * This'll screw the version control
- *
- * Revision 1.6  1998/09/30 00:40:38  dwmw2
- * Updated to use kernel's N_R3964 if available
- *
- * Revision 1.4  1998/04/02 20:29:44  lhaag
- * select, blocking, ...
- *
- * Revision 1.3  1998/02/12 18:58:43  root
- * fixed some memory leaks
- * calculation of checksum characters
- *
- * Revision 1.2  1998/02/07 13:03:17  root
- * ioctl read_telegram
- *
- * Revision 1.1  1998/02/06 19:19:43  root
- * Initial revision
- *
- *
- */
-
-#ifndef _UAPI__LINUX_N_R3964_H__
-#define _UAPI__LINUX_N_R3964_H__
-
-/* line disciplines for r3964 protocol */
-
-
-/*
- * Ioctl-commands
- */
-
-#define R3964_ENABLE_SIGNALS      0x5301
-#define R3964_SETPRIORITY         0x5302
-#define R3964_USE_BCC             0x5303
-#define R3964_READ_TELEGRAM       0x5304
-
-/* Options for R3964_SETPRIORITY */
-#define R3964_MASTER   0
-#define R3964_SLAVE    1
-
-/* Options for R3964_ENABLE_SIGNALS */
-#define R3964_SIG_ACK   0x0001
-#define R3964_SIG_DATA  0x0002
-#define R3964_SIG_ALL   0x000f
-#define R3964_SIG_NONE  0x0000
-#define R3964_USE_SIGIO 0x1000
-
-/*
- * r3964 operation states:
- */
-
-/* types for msg_id: */
-enum {R3964_MSG_ACK=1, R3964_MSG_DATA };
-
-#define R3964_MAX_MSG_COUNT 32
-
-/* error codes for client messages */
-#define R3964_OK 0        /* no error. */
-#define R3964_TX_FAIL -1  /* transmission error, block NOT sent */
-#define R3964_OVERFLOW -2 /* msg queue overflow */
-
-/* the client gets this struct when calling read(fd,...): */
-struct r3964_client_message {
-	  int     msg_id;
-	  int     arg;
-	  int     error_code;
-};
-
-#define R3964_MTU      256
-
-
-
-#endif /* _UAPI__LINUX_N_R3964_H__ */