arch/ppc64/kernel/ItLpQueue.c

   1 /*
   2  * ItLpQueue.c
   3  * Copyright (C) 2001 Mike Corrigan  IBM Corporation
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  */
  10
  11 #include <linux/stddef.h>
  12 #include <linux/kernel.h>
  13 #include <linux/sched.h>
  14 #include <asm/system.h>
  15 #include <asm/paca.h>
  16 #include <asm/iSeries/ItLpQueue.h>
  17 #include <asm/iSeries/HvLpEvent.h>
  18 #include <asm/iSeries/HvCallEvent.h>
  19
  20 static __inline__ int set_inUse( struct ItLpQueue * lpQueue )
  21 {
  22         int t;
  23         u32 * inUseP = &(lpQueue->xInUseWord);
  24
  25         __asm__ __volatile__("\n\
  26 1:      lwarx   %0,0,%2         \n\
  27         cmpwi   0,%0,0          \n\
  28         li      %0,0            \n\
  29         bne-    2f              \n\
  30         addi    %0,%0,1         \n\
  31         stwcx.  %0,0,%2         \n\
  32         bne-    1b              \n\
  33 2:      eieio"
  34         : "=&r" (t), "=m" (lpQueue->xInUseWord)
  35         : "r" (inUseP), "m" (lpQueue->xInUseWord)
  36         : "cc");
  37
  38         return t;
  39 }
  40
  41 static __inline__ void clear_inUse( struct ItLpQueue * lpQueue )
  42 {
  43         lpQueue->xInUseWord = 0;
  44 }
  45
  46 /* Array of LpEvent handler functions */
  47 extern LpEventHandler lpEventHandler[HvLpEvent_Type_NumTypes];
  48 unsigned long ItLpQueueInProcess = 0;
  49
  50 struct HvLpEvent * ItLpQueue_getNextLpEvent( struct ItLpQueue * lpQueue )
  51 {
  52         struct HvLpEvent * nextLpEvent =
  53                 (struct HvLpEvent *)lpQueue->xSlicCurEventPtr;
  54         if ( nextLpEvent->xFlags.xValid ) {
  55                 /* rmb() needed only for weakly consistent machines (regatta) */
  56                 rmb();
  57                 /* Set pointer to next potential event */
  58                 lpQueue->xSlicCurEventPtr += ((nextLpEvent->xSizeMinus1 +
  59                                       LpEventAlign ) /
  60                                       LpEventAlign ) *
  61                                       LpEventAlign;
  62                 /* Wrap to beginning if no room at end */
  63                 if (lpQueue->xSlicCurEventPtr > lpQueue->xSlicLastValidEventPtr)
  64                         lpQueue->xSlicCurEventPtr = lpQueue->xSlicEventStackPtr;
  65         }
  66         else
  67                 nextLpEvent = NULL;
  68
  69         return nextLpEvent;
  70 }
  71
  72 int ItLpQueue_isLpIntPending( struct ItLpQueue * lpQueue )
  73 {
  74         int retval = 0;
  75         struct HvLpEvent * nextLpEvent;
  76         if ( lpQueue ) {
  77                 nextLpEvent = (struct HvLpEvent *)lpQueue->xSlicCurEventPtr;
  78                 retval = nextLpEvent->xFlags.xValid | lpQueue->xPlicOverflowIntPending;
  79         }
  80         return retval;
  81 }
  82
  83 void ItLpQueue_clearValid( struct HvLpEvent * event )
  84 {
  85         /* Clear the valid bit of the event
  86          * Also clear bits within this event that might
  87          * look like valid bits (on 64-byte boundaries)
  88          */
  89         unsigned extra = (( event->xSizeMinus1 + LpEventAlign ) /
  90                                                  LpEventAlign ) - 1;
  91         switch ( extra ) {
  92           case 3:
  93            ((struct HvLpEvent*)((char*)event+3*LpEventAlign))->xFlags.xValid=0;
  94           case 2:
  95            ((struct HvLpEvent*)((char*)event+2*LpEventAlign))->xFlags.xValid=0;
  96           case 1:
  97            ((struct HvLpEvent*)((char*)event+1*LpEventAlign))->xFlags.xValid=0;
  98           case 0:
  99            ;
 100         }
 101         mb();
 102         event->xFlags.xValid = 0;
 103 }
 104
 105 unsigned ItLpQueue_process( struct ItLpQueue * lpQueue, struct pt_regs *regs )
 106 {
 107         unsigned numIntsProcessed = 0;
 108         struct HvLpEvent * nextLpEvent;
 109
 110         /* If we have recursed, just return */
 111         if ( !set_inUse( lpQueue ) )
 112                 return 0;
 113
 114         if (ItLpQueueInProcess == 0)
 115                 ItLpQueueInProcess = 1;
 116         else
 117                 BUG();
 118
 119         for (;;) {
 120                 nextLpEvent = ItLpQueue_getNextLpEvent( lpQueue );
 121                 if ( nextLpEvent ) {
 122                         /* Count events to return to caller
 123                          * and count processed events in lpQueue
 124                          */
 125                         ++numIntsProcessed;
 126                         lpQueue->xLpIntCount++;
 127                         /* Call appropriate handler here, passing
 128                          * a pointer to the LpEvent.  The handler
 129                          * must make a copy of the LpEvent if it
 130                          * needs it in a bottom half. (perhaps for
 131                          * an ACK)
 132                          *
 133                          *  Handlers are responsible for ACK processing
 134                          *
 135                          * The Hypervisor guarantees that LpEvents will
 136                          * only be delivered with types that we have
 137                          * registered for, so no type check is necessary
 138                          * here!
 139                          */
 140                         if ( nextLpEvent->xType < HvLpEvent_Type_NumTypes )
 141                                 lpQueue->xLpIntCountByType[nextLpEvent->xType]++;
 142                         if ( nextLpEvent->xType < HvLpEvent_Type_NumTypes &&
 143                              lpEventHandler[nextLpEvent->xType] )
 144                                 lpEventHandler[nextLpEvent->xType](nextLpEvent, regs);
 145                         else
 146                                 printk(KERN_INFO "Unexpected Lp Event type=%d\n", nextLpEvent->xType );
 147
 148                         ItLpQueue_clearValid( nextLpEvent );
 149                 } else if ( lpQueue->xPlicOverflowIntPending )
 150                         /*
 151                          * No more valid events. If overflow events are
 152                          * pending process them
 153                          */
 154                         HvCallEvent_getOverflowLpEvents( lpQueue->xIndex);
 155                 else
 156                         break;
 157         }
 158
 159         ItLpQueueInProcess = 0;
 160         mb();
 161         clear_inUse( lpQueue );
 162
 163         get_paca()->lpevent_count += numIntsProcessed;
 164
 165         return numIntsProcessed;
 166 }