itlpqueue.c

来自「是关于linux2.5.1的完全源码」· C语言 代码 · 共 179 行

/* 
 * ItLpQueue.c
 * Copyright (C) 2001 Mike Corrigan  IBM Corporation
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <asm/system.h>
#include <asm/iSeries/ItLpQueue.h>
#include <asm/iSeries/HvLpEvent.h>
#include <asm/iSeries/HvCallEvent.h>
#include <asm/iSeries/LparData.h>

static __inline__ int set_inUse( struct ItLpQueue * lpQueue )
{
	int t;
	u32 * inUseP = &(lpQueue->xInUseWord);

	__asm__ __volatile__("\n\
1:	lwarx	%0,0,%2		\n\
	cmpi	0,%0,0		\n\
	li	%0,0		\n\
	bne-	2f		\n\
	addi	%0,%0,1		\n\
	stwcx.	%0,0,%2		\n\
	bne-	1b		\n\
2:	eieio"
	: "=&r" (t), "=m" (lpQueue->xInUseWord)
	: "r" (inUseP), "m" (lpQueue->xInUseWord)
	: "cc");

	return t;
}

static __inline__ void clear_inUse( struct ItLpQueue * lpQueue )
{
	lpQueue->xInUseWord = 0;
}

// Array of LpEvent handler functions
extern LpEventHandler lpEventHandler[HvLpEvent_Type_NumTypes];
unsigned long ItLpQueueInProcess = 0;

struct HvLpEvent * ItLpQueue_getNextLpEvent( struct ItLpQueue * lpQueue )
{
	struct HvLpEvent * nextLpEvent = 
		(struct HvLpEvent *)lpQueue->xSlicCurEventPtr;
	if ( nextLpEvent->xFlags.xValid ) {
		// Set pointer to next potential event 
		lpQueue->xSlicCurEventPtr += ((nextLpEvent->xSizeMinus1 +
				      LpEventAlign ) /
				      LpEventAlign ) *
				      LpEventAlign;
		// Wrap to beginning if no room at end
		if (lpQueue->xSlicCurEventPtr > lpQueue->xSlicLastValidEventPtr)
			lpQueue->xSlicCurEventPtr = lpQueue->xSlicEventStackPtr;
	}
	else 
		nextLpEvent = NULL;

	return nextLpEvent;
}

int ItLpQueue_isLpIntPending( struct ItLpQueue * lpQueue )
{
	struct HvLpEvent * nextLpEvent =
		(struct HvLpEvent *)lpQueue->xSlicCurEventPtr;
	return ( nextLpEvent->xFlags.xValid |
		 lpQueue->xPlicOverflowIntPending);
}

void ItLpQueue_clearValid( struct HvLpEvent * event )
{
	// Clear the valid bit of the event
	// Also clear bits within this event that might
	// look like valid bits (on 64-byte boundaries)
	unsigned extra = (( event->xSizeMinus1 + LpEventAlign ) /
						 LpEventAlign ) - 1;
	switch ( extra ) {
	  case 3:
	   ((struct HvLpEvent*)((char*)event+3*LpEventAlign))->xFlags.xValid=0;
	  case 2:
	   ((struct HvLpEvent*)((char*)event+2*LpEventAlign))->xFlags.xValid=0;
	  case 1:
	   ((struct HvLpEvent*)((char*)event+1*LpEventAlign))->xFlags.xValid=0;
	  case 0:
	}
	mb();
	event->xFlags.xValid = 0;
}

// No lock is necessary when processing the Lp Queue because a single
// processor is assigned to each lpqueue.  Interrupts are disabled
// while processing events.
// Some device drivers' interrupt handlers run with interrupts 
// enabled.  This requires us to prevent being re-entered here.
// We use the xInUse flag for that.

unsigned lpQueue_proc_count[32] = {};

unsigned ItLpQueue_process( struct ItLpQueue * lpQueue, struct pt_regs *regs )
{
	unsigned numIntsProcessed = 0;
	struct HvLpEvent * nextLpEvent;

	// If we have recursed, just return
	if ( !set_inUse( lpQueue ) )
		return 0;
	
	if (ItLpQueueInProcess == 0)
	    ItLpQueueInProcess = 1;
	else
	    BUG();
	
	++lpQueue_proc_count[current->processor];
	
	for (;;) {
		nextLpEvent = ItLpQueue_getNextLpEvent( lpQueue );
		
		if ( nextLpEvent ) {
			// Count events to return to caller
			// and count processed events in lpQueue
			++numIntsProcessed;
			lpQueue->xLpIntCount++;		
			// Call appropriate handler here, passing 
			// a pointer to the LpEvent.  The handler
			// must make a copy of the LpEvent if it
			// needs it in a bottom half. (perhaps for
			// an ACK)
			
			//  Handlers are responsible for ACK processing 

			// The Hypervisor guarantees that LpEvents will
			// only be delivered with types that we have
			// registered for, so no type check is necessary
			// here!
			if ( nextLpEvent->xType < HvLpEvent_Type_NumTypes )
				lpQueue->xLpIntCountByType[nextLpEvent->xType]++;
			if ( nextLpEvent->xType < HvLpEvent_Type_NumTypes &&
			     lpEventHandler[nextLpEvent->xType] ) 
				lpEventHandler[nextLpEvent->xType](nextLpEvent, regs);
			else
				printk(KERN_INFO "Unexpected Lp Event type=%d\n", nextLpEvent->xType );
			
			ItLpQueue_clearValid( nextLpEvent );
		}
		else 	// No more valid events
			// If overflow events are pending
			// process them
			if ( lpQueue->xPlicOverflowIntPending ) {
				HvCallEvent_getOverflowLpEvents( 
						lpQueue->xIndex);
			}
			else	// If nothing left then we are done
				break;
	}

	ItLpQueueInProcess = 0;
	mb();
	clear_inUse( lpQueue );

	return numIntsProcessed;
}