drivers/s390/cio/airq.c

   1 /*
   2  *  drivers/s390/cio/airq.c
   3  *   S/390 common I/O routines -- support for adapter interruptions
   4  *
   5  *   $Revision: 1.12 $
   6  *
   7  *    Copyright (C) 1999-2002 IBM Deutschland Entwicklung GmbH,
   8  *                            IBM Corporation
   9  *    Author(s): Ingo Adlung (adlung@de.ibm.com)
  10  *               Cornelia Huck (cohuck@de.ibm.com)
  11  *               Arnd Bergmann (arndb@de.ibm.com)
  12  */
  13
  14 #include <linux/init.h>
  15 #include <linux/module.h>
  16 #include <linux/slab.h>
  17 #include <linux/rcupdate.h>
  18
  19 #include "cio_debug.h"
  20 #include "airq.h"
  21
  22 static adapter_int_handler_t adapter_handler;
  23
  24 /*
  25  * register for adapter interrupts
  26  *
  27  * With HiperSockets the zSeries architecture provides for
  28  *  means of adapter interrups, pseudo I/O interrupts that are
  29  *  not tied to an I/O subchannel, but to an adapter. However,
  30  *  it doesn't disclose the info how to enable/disable them, but
  31  *  to recognize them only. Perhaps we should consider them
  32  *  being shared interrupts, and thus build a linked list
  33  *  of adapter handlers ... to be evaluated ...
  34  */
  35 int
  36 s390_register_adapter_interrupt (adapter_int_handler_t handler)
  37 {
  38         int ret;
  39         char dbf_txt[15];
  40
  41         CIO_TRACE_EVENT (4, "rgaint");
  42
  43         if (handler == NULL)
  44                 ret = -EINVAL;
  45         else
  46                 ret = (cmpxchg(&adapter_handler, NULL, handler) ? -EBUSY : 0);
  47         if (!ret)
  48                 synchronize_sched();  /* Allow interrupts to complete. */
  49
  50         sprintf (dbf_txt, "ret:%d", ret);
  51         CIO_TRACE_EVENT (4, dbf_txt);
  52
  53         return ret;
  54 }
  55
  56 int
  57 s390_unregister_adapter_interrupt (adapter_int_handler_t handler)
  58 {
  59         int ret;
  60         char dbf_txt[15];
  61
  62         CIO_TRACE_EVENT (4, "urgaint");
  63
  64         if (handler == NULL)
  65                 ret = -EINVAL;
  66         else {
  67                 adapter_handler = NULL;
  68                 synchronize_sched();  /* Allow interrupts to complete. */
  69                 ret = 0;
  70         }
  71         sprintf (dbf_txt, "ret:%d", ret);
  72         CIO_TRACE_EVENT (4, dbf_txt);
  73
  74         return ret;
  75 }
  76
  77 void
  78 do_adapter_IO (void)
  79 {
  80         CIO_TRACE_EVENT (6, "doaio");
  81
  82         if (adapter_handler)
  83                 (*adapter_handler) ();
  84 }
  85
  86 EXPORT_SYMBOL (s390_register_adapter_interrupt);
  87 EXPORT_SYMBOL (s390_unregister_adapter_interrupt);