BOOL
CPCIDisk::BeginDMA(
BOOL fRead
)
{
BYTE bStatus, bCommand;
CacheSync(CACHE_SYNC_DISCARD);
WriteBMCommand(0);
ASSERT(0 == m_pPRDPhys.HighPart);
WriteBMTable(m_pPRDPhys.LowPart);
bStatus = ReadBMStatus();
bStatus |= 0x06;
// bStatus |= 0x66;
WriteBMStatus(bStatus);
if (fRead) {
bCommand = 0x08 | 0x01;
}
else {
bCommand = 0x00 | 0x01;
}
WriteBMCommand(bCommand);
bStatus = ReadBMStatus();
return TRUE;
}
SysStatusUval
FCMDefault::getForkPage(
PageDesc* callerPg, uval& returnUval, FCMComputationRef& childRef,
PageFaultNotification *fn, uval copyOnWrite)
{
SysStatusUval rc;
PageDesc *pg;
uval fileOffset;
fileOffset = callerPg->fileOffset;
rc = getPageInternal(fileOffset, fn, pg, copyOnWrite);
/*
* rc == 0 if page was gotten and FCM was locked
* rc >0 if io is in progress and fn will be posted
* rc <0 failure
*/
if (_SUCCESS(rc) && (rc == 0)) {
//available
callerPg->paddr = pg->paddr;
// cant do copyonwrite to we can call back to unmap
#if 0
/* check for copy on write first. Thus, a frame that
* we could give to the child is instead mapped
* copyOnWrite.
*
* The normal case is a child/parent pair (the shell)
* continuously creating a new second child which then
* terminates.
*
* In that case, this order collects all the read only
* data pages in the fork parent, and they never are
* unmapped in the shell. Only the written pages
* will be moved from the shell child to the parent
* at fork.
*
* The down side is that a read/write sequence on a
* page which could be moved up will be more expensive,
* particularly if the page is already dirty so we could
* have mapped it read/write in the child immediately.
*
* The alternative is to move this check below the
* check for giving the frame to the parent.
*/
if (copyOnWrite) {
//caller can accept copy on write mapping
callerPg->paddr = pg->paddr;
pg->ppset |= uval(1) << Scheduler::GetVP();
if (pg->cacheSynced == PageDesc::CLEAR) {
// Machine dependent operation.
setPFBit(CacheSynced);
CacheSync(pg);
}
if (pg->mapped != PageDesc::SET) {
// mark page mapped
pg->mapped = PageDesc::SET;
// also mark framearray to indicate page is now mapped
// PageAllocatorKernPinned::setAccessed(pg->paddr);
}
lock.release();
return MAPPAGE;
}
#endif
// page lock held until unLockPage call
pg->doingIO = PageDesc::SET;
// copy our ppset to caller to it can unmap if needed
// (only happens if copyonwrite logic is enabled)
callerPg->ppset = pg->ppset;
callerPg->mapped = pg->mapped;
returnUval = uval(pg); // caller needs this to unlock
lock.release();
return FRAMETOCOPY;
}
// doingIO
return (rc>0)?DOINGIO:rc;
}
