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 #include <asm/iSeries/LparData.h>
  20
  21 static __inline__ int set_inUse( struct ItLpQueue * lpQueue )
  22 {
  23         int t;
  24         u32 * inUseP = &(lpQueue->xInUseWord);
  25
  26         __asm__ __volatile__("\n\
  27 1:      lwarx   %0,0,%2         \n\
  28         cmpi    0,%0,0          \n\
  29         li      %0,0            \n\
  30         bne-    2f              \n\
  31         addi    %0,%0,1         \n\
  32         stwcx.  %0,0,%2         \n\
  33         bne-    1b              \n\
  34 2:      eieio"
  35         : "=&r" (t), "=m" (lpQueue->xInUseWord)
  36         : "r" (inUseP), "m" (lpQueue->xInUseWord)
  37         : "cc");
  38
  39         return t;
  40 }
  41
  42 static __inline__ void clear_inUse( struct ItLpQueue * lpQueue )
  43 {
  44         lpQueue->xInUseWord = 0;
  45 }
  46
  47 /* Array of LpEvent handler functions */
  48 extern LpEventHandler lpEventHandler[HvLpEvent_Type_NumTypes];
  49 unsigned long ItLpQueueInProcess = 0;
  50
  51 struct HvLpEvent * ItLpQueue_getNextLpEvent( struct ItLpQueue * lpQueue )
  52 {
  53         struct HvLpEvent * nextLpEvent =
  54                 (struct HvLpEvent *)lpQueue->xSlicCurEventPtr;
  55         if ( nextLpEvent->xFlags.xValid ) {
  56                 /* rmb() needed only for weakly consistent machines (regatta) */
  57                 rmb();
  58                 /* Set pointer to next potential event */
  59                 lpQueue->xSlicCurEventPtr += ((nextLpEvent->xSizeMinus1 +
  60                                       LpEventAlign ) /
  61                                       LpEventAlign ) *
  62                                       LpEventAlign;
  63                 /* Wrap to beginning if no room at end */
  64                 if (lpQueue->xSlicCurEventPtr > lpQueue->xSlicLastValidEventPtr)
  65                         lpQueue->xSlicCurEventPtr = lpQueue->xSlicEventStackPtr;
  66         }
  67         else
  68                 nextLpEvent = NULL;
  69
  70         return nextLpEvent;
  71 }
  72
  73 int ItLpQueue_isLpIntPending( struct ItLpQueue * lpQueue )
  74 {
  75         int retval = 0;
  76         struct HvLpEvent * nextLpEvent;
  77         if ( lpQueue ) {
  78                 nextLpEvent = (struct HvLpEvent *)lpQueue->xSlicCurEventPtr;
  79                 retval = nextLpEvent->xFlags.xValid | lpQueue->xPlicOverflowIntPending;
  80         }
  81         return retval;
  82 }
  83
  84 void ItLpQueue_clearValid( struct HvLpEvent * event )
  85 {
  86         /* Clear the valid bit of the event
  87          * Also clear bits within this event that might
  88          * look like valid bits (on 64-byte boundaries)
  89          */
  90         unsigned extra = (( event->xSizeMinus1 + LpEventAlign ) /
  91                                                  LpEventAlign ) - 1;
  92         switch ( extra ) {
  93           case 3:
  94            ((struct HvLpEvent*)((char*)event+3*LpEventAlign))->xFlags.xValid=0;
  95           case 2:
  96            ((struct HvLpEvent*)((char*)event+2*LpEventAlign))->xFlags.xValid=0;
  97           case 1:
  98            ((struct HvLpEvent*)((char*)event+1*LpEventAlign))->xFlags.xValid=0;
  99           case 0:
 100            ;
 101         }
 102         mb();
 103         event->xFlags.xValid = 0;
 104 }
 105
 106 unsigned ItLpQueue_process( struct ItLpQueue * lpQueue, struct pt_regs *regs )
 107 {
 108         unsigned numIntsProcessed = 0;
 109         struct HvLpEvent * nextLpEvent;
 110
 111         /* If we have recursed, just return */
 112         if ( !set_inUse( lpQueue ) )
 113                 return 0;
 114
 115         if (ItLpQueueInProcess == 0)
 116                 ItLpQueueInProcess = 1;
 117         else
 118                 BUG();
 119
 120         for (;;) {
 121                 nextLpEvent = ItLpQueue_getNextLpEvent( lpQueue );
 122                 if ( nextLpEvent ) {
 123                         /* Count events to return to caller
 124                          * and count processed events in lpQueue
 125                          */
 126                         ++numIntsProcessed;
 127                         lpQueue->xLpIntCount++;
 128                         /* Call appropriate handler here, passing
 129                          * a pointer to the LpEvent.  The handler
 130                          * must make a copy of the LpEvent if it
 131                          * needs it in a bottom half. (perhaps for
 132                          * an ACK)
 133                          *
 134                          *  Handlers are responsible for ACK processing
 135                          *
 136                          * The Hypervisor guarantees that LpEvents will
 137                          * only be delivered with types that we have
 138                          * registered for, so no type check is necessary
 139                          * here!
 140                          */
 141                         if ( nextLpEvent->xType < HvLpEvent_Type_NumTypes )
 142                                 lpQueue->xLpIntCountByType[nextLpEvent->xType]++;
 143                         if ( nextLpEvent->xType < HvLpEvent_Type_NumTypes &&
 144                              lpEventHandler[nextLpEvent->xType] )
 145                                 lpEventHandler[nextLpEvent->xType](nextLpEvent, regs);
 146                         else
 147                                 printk(KERN_INFO "Unexpected Lp Event type=%d\n", nextLpEvent->xType );
 148
 149                         ItLpQueue_clearValid( nextLpEvent );
 150                 } else if ( lpQueue->xPlicOverflowIntPending )
 151                         /*
 152                          * No more valid events. If overflow events are
 153                          * pending process them
 154                          */
 155                         HvCallEvent_getOverflowLpEvents( lpQueue->xIndex);
 156                 else
 157                         break;
 158         }
 159
 160         ItLpQueueInProcess = 0;
 161         mb();
 162         clear_inUse( lpQueue );
 163
 164         get_paca()->lpEvent_count += numIntsProcessed;
 165
 166         return numIntsProcessed;
 167 }