arch/ppc64/kernel/HvLpEvent.c

   1 /*
   2  * Copyright 2001 Mike Corrigan IBM Corp
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version
   7  * 2 of the License, or (at your option) any later version.
   8  */
   9 #include <linux/stddef.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <asm/system.h>
  13 #include <asm/iSeries/HvLpEvent.h>
  14 #include <asm/iSeries/HvCallEvent.h>
  15 #include <asm/iSeries/LparData.h>
  16
  17 /* Array of LpEvent handler functions */
  18 LpEventHandler lpEventHandler[HvLpEvent_Type_NumTypes];
  19 unsigned lpEventHandlerPaths[HvLpEvent_Type_NumTypes];
  20
  21 /* Register a handler for an LpEvent type */
  22
  23 int HvLpEvent_registerHandler( HvLpEvent_Type eventType, LpEventHandler handler )
  24 {
  25         int rc = 1;
  26         if ( eventType < HvLpEvent_Type_NumTypes ) {
  27                 lpEventHandler[eventType] = handler;
  28                 rc = 0;
  29         }
  30         return rc;
  31
  32 }
  33
  34 int HvLpEvent_unregisterHandler( HvLpEvent_Type eventType )
  35 {
  36         int rc = 1;
  37
  38         might_sleep();
  39
  40         if ( eventType < HvLpEvent_Type_NumTypes ) {
  41                 if ( !lpEventHandlerPaths[eventType] ) {
  42                         lpEventHandler[eventType] = NULL;
  43                         rc = 0;
  44
  45                         /* We now sleep until all other CPUs have scheduled. This ensures that
  46                          * the deletion is seen by all other CPUs, and that the deleted handler
  47                          * isn't still running on another CPU when we return. */
  48                         synchronize_rcu();
  49                 }
  50         }
  51         return rc;
  52 }
  53 EXPORT_SYMBOL(HvLpEvent_registerHandler);
  54 EXPORT_SYMBOL(HvLpEvent_unregisterHandler);
  55
  56 /* (lpIndex is the partition index of the target partition.
  57  * needed only for VirtualIo, VirtualLan and SessionMgr.  Zero
  58  * indicates to use our partition index - for the other types)
  59  */
  60 int HvLpEvent_openPath( HvLpEvent_Type eventType, HvLpIndex lpIndex )
  61 {
  62         int rc = 1;
  63         if ( eventType < HvLpEvent_Type_NumTypes &&
  64              lpEventHandler[eventType] ) {
  65                 if ( lpIndex == 0 )
  66                         lpIndex = itLpNaca.xLpIndex;
  67                 HvCallEvent_openLpEventPath( lpIndex, eventType );
  68                 ++lpEventHandlerPaths[eventType];
  69                 rc = 0;
  70         }
  71         return rc;
  72 }
  73
  74 int HvLpEvent_closePath( HvLpEvent_Type eventType, HvLpIndex lpIndex )
  75 {
  76         int rc = 1;
  77         if ( eventType < HvLpEvent_Type_NumTypes &&
  78              lpEventHandler[eventType] &&
  79              lpEventHandlerPaths[eventType] ) {
  80                 if ( lpIndex == 0 )
  81                         lpIndex = itLpNaca.xLpIndex;
  82                 HvCallEvent_closeLpEventPath( lpIndex, eventType );
  83                 --lpEventHandlerPaths[eventType];
  84                 rc = 0;
  85         }
  86         return rc;
  87 }
  88