include/asm-s390/tape390.h

   1 /*************************************************************************
   2  *
   3  * tape390.h
   4  *         enables user programs to display messages on the tape device
   5  *
   6  *  S390 and zSeries version
   7  *         Copyright (C) 2001 IBM Corporation
   8  *         Author(s): Despina Papadopoulou <despina_p@de.ibm.com>
   9  *
  10  *************************************************************************/
  11
  12 #ifndef _TAPE390_H
  13 #define _TAPE390_H
  14
  15 #define TAPE390_DISPLAY _IOW('d', 1, struct display_struct)
  16
  17 /*
  18  * The TAPE390_DISPLAY ioctl calls the Load Display command
  19  * which transfers 17 bytes of data from the channel to the subsystem:
  20  *     - 1 format control byte, and
  21  *     - two 8-byte messages
  22  *
  23  * Format control byte:
  24  *   0-2: New Message Overlay
  25  *     3: Alternate Messages
  26  *     4: Blink Message
  27  *     5: Display Low/High Message
  28  *     6: Reserved
  29  *     7: Automatic Load Request
  30  *
  31  */
  32
  33 typedef struct display_struct {
  34         char cntrl;
  35         char message1[8];
  36         char message2[8];
  37 } display_struct;
  38
  39 #endif