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: 1.11 $
   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
  18 #include "cio_debug.h"
  19 #include "airq.h"
  20
  21 static spinlock_t adapter_lock = SPIN_LOCK_UNLOCKED;
  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         spin_lock (&adapter_lock);
  44
  45         if (handler == NULL)
  46                 ret = -EINVAL;
  47         else if (adapter_handler)
  48                 ret = -EBUSY;
  49         else {
  50                 adapter_handler = handler;
  51                 ret = 0;
  52         }
  53
  54         spin_unlock (&adapter_lock);
  55
  56         sprintf (dbf_txt, "ret:%d", ret);
  57         CIO_TRACE_EVENT (4, dbf_txt);
  58
  59         return (ret);
  60 }
  61
  62 int
  63 s390_unregister_adapter_interrupt (adapter_int_handler_t handler)
  64 {
  65         int ret;
  66         char dbf_txt[15];
  67
  68         CIO_TRACE_EVENT (4, "urgaint");
  69
  70         spin_lock (&adapter_lock);
  71
  72         if (handler == NULL)
  73                 ret = -EINVAL;
  74         else if (handler != adapter_handler)
  75                 ret = -EINVAL;
  76         else {
  77                 adapter_handler = NULL;
  78                 ret = 0;
  79         }
  80
  81         spin_unlock (&adapter_lock);
  82
  83         sprintf (dbf_txt, "ret:%d", ret);
  84         CIO_TRACE_EVENT (4, dbf_txt);
  85
  86         return (ret);
  87 }
  88
  89 void
  90 do_adapter_IO (void)
  91 {
  92         CIO_TRACE_EVENT (4, "doaio");
  93
  94         spin_lock (&adapter_lock);
  95
  96         if (adapter_handler)
  97                 (*adapter_handler) ();
  98
  99         spin_unlock (&adapter_lock);
 100
 101         return;
 102 }
 103
 104 EXPORT_SYMBOL (s390_register_adapter_interrupt);
 105 EXPORT_SYMBOL (s390_unregister_adapter_interrupt);