s390io.c

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	}
	/*
	 * we ignore the clear_io() request if ending_status was received but
	 *  a SENSE operation is waiting for completion.
	 */
	else if ( ioinfo[irq]->ui.flags.w4sense )
	{
		ret = 0;
	}
	else
	{
		if (cio_debug_initialized) {
			sprintf(dbf_txt, "clearIO%x", irq);
			debug_text_event(cio_debug_trace_id, 2, dbf_txt);
		}
		/*
		 * If sync processing was requested we lock the sync ISC,
		 *  modify the device to present interrupts for this ISC only
		 *  and switch the CPU to handle this ISC + the console ISC
		 *  exclusively.
		 */
		if ( flag & DOIO_WAIT_FOR_INTERRUPT )
		{
			ret = enable_cpu_sync_isc( irq);

			if ( ret )
			{
				return( ret);
  	
			} /* endif */

		} /* endif */

		/*
		 * Issue "Clear subchannel" and process condition code
		 */
		ccode = csch( irq );

		if (cio_debug_initialized) {
			sprintf(dbf_txt, "ccode:%d",ccode);
			debug_text_event(cio_debug_trace_id, 2, dbf_txt);
		}

		switch ( ccode ) {
		case 0:

			ioinfo[irq]->ui.flags.haltio = 1;

			if ( !ioinfo[irq]->ui.flags.doio )
			{
				ioinfo[irq]->ui.flags.busy   = 1;
				ioinfo[irq]->u_intparm       = user_intparm;
				ioinfo[irq]->devstat.cstat   = 0;
				ioinfo[irq]->devstat.dstat   = 0;
				ioinfo[irq]->devstat.lpum    = 0;
				ioinfo[irq]->devstat.flag    = DEVSTAT_CLEAR_FUNCTION;
				ioinfo[irq]->devstat.scnt    = 0;

			}
			else
			{
				ioinfo[irq]->devstat.flag   |= DEVSTAT_CLEAR_FUNCTION;

			} /* endif */

			/*
			 * If synchronous I/O processing is requested, we have
			 *  to wait for the corresponding interrupt to occur by
			 *  polling the interrupt condition. However, as multiple
			 *  interrupts may be outstanding, we must not just wait
			 *  for the first interrupt, but must poll until ours
			 *  pops up.
			 */
			if ( flag & DOIO_WAIT_FOR_INTERRUPT )
			{
				int              io_sub;
				__u32            io_parm;
				psw_t            io_new_psw;
				int              ccode;
  	
				int              ready = 0;
				struct _lowcore *lc    = NULL;

				/*
				 * We shouldn't perform a TPI loop, waiting for
				 *  an interrupt to occur, but should load a
				 *  WAIT PSW instead. Otherwise we may keep the
				 *  channel subsystem busy, not able to present
				 *  the interrupt. When our sync. interrupt
				 *  arrived we reset the I/O old PSW to its
				 *  original value.
				 */
				memcpy( &io_new_psw,
				        &lc->io_new_psw,
				        sizeof(psw_t));

				ccode = iac();

				switch (ccode) {
				case 0:  		// primary-space
					io_sync_wait.mask =   _IO_PSW_MASK
					                    | _PSW_PRIM_SPACE_MODE
					                    | _PSW_IO_WAIT;
					break;
				case 1:			// secondary-space
					io_sync_wait.mask =   _IO_PSW_MASK
					                    | _PSW_SEC_SPACE_MODE
					                    | _PSW_IO_WAIT;
					break;
				case 2:			// access-register
					io_sync_wait.mask =   _IO_PSW_MASK
					                    | _PSW_ACC_REG_MODE
					                    | _PSW_IO_WAIT;
					break;
				case 3:			// home-space	
					io_sync_wait.mask =   _IO_PSW_MASK
					                    | _PSW_HOME_SPACE_MODE
					                    | _PSW_IO_WAIT;
					break;
				default:
					panic( "clear_IO() : unexpected "
					       "address-space-control %d\n",
					       ccode);
					break;
				} /* endswitch */

				io_sync_wait.addr = FIX_PSW(&&cio_wakeup);

				/*
				 * Martin didn't like modifying the new PSW, now we take
				 *  a fast exit in do_IRQ() instead
				 */
				*(__u32 *)__LC_SYNC_IO_WORD  = 1;

				do
				{

					__load_psw( io_sync_wait );
cio_wakeup:
				   io_parm = *(__u32 *)__LC_IO_INT_PARM;
				   io_sub  = (__u32)*(__u16 *)__LC_SUBCHANNEL_NR;

				   ready = s390_process_IRQ( io_sub );

				} while ( !((io_sub == irq) && (ready == 1)) );

				*(__u32 *)__LC_SYNC_IO_WORD = 0;

			} /* endif */

			ret = 0;
			break;

		case 1 :            /* no status pending for csh */
			BUG();
			break;


		case 2 :            /* no busy for csh*/
			BUG();
			break;

		default:            /* device not operational */

			ret = -ENODEV;
			break;

		} /* endswitch */

		if ( flag & DOIO_WAIT_FOR_INTERRUPT )
		{
			disable_cpu_sync_isc( irq );

		} /* endif */

	} /* endif */

	return( ret );
}


/*
 * do_IRQ() handles all normal I/O device IRQ's (the special
 *          SMP cross-CPU interrupts have their own specific
 *          handlers).
 *
 */
asmlinkage void do_IRQ( struct pt_regs regs )
{
	/*
	 * Get interrupt info from lowcore
	 */
	volatile tpi_info_t *tpi_info = (tpi_info_t*)(__LC_SUBCHANNEL_ID);
	int cpu = smp_processor_id();

	/*
	 * take fast exit if CPU is in sync. I/O state
	 *
	 * Note: we have to turn off the WAIT bit and re-disable
	 *       interrupts prior to return as this was the initial
	 *       entry condition to synchronous I/O.
	 */
 	if (    *(__u32 *)__LC_SYNC_IO_WORD )
	{
		regs.psw.mask &= ~(_PSW_WAIT_MASK_BIT | _PSW_IO_MASK_BIT);
		return;
	} /* endif */

#ifdef CONFIG_FAST_IRQ
	do {
#endif /*  CONFIG_FAST_IRQ */
		
		/*
		 * Non I/O-subchannel thin interrupts are processed differently
		 */
		if ( tpi_info->adapter_IO == 1 &&
		     tpi_info->int_type == IO_INTERRUPT_TYPE )
		{
			irq_enter(cpu, -1);
			do_adapter_IO( tpi_info->intparm );
			irq_exit(cpu, -1);
		} 
		else 
		{
			unsigned int irq = tpi_info->irq;
	
			/*
			 * fix me !!!
			 *
			 * instead of boxing the device, we need to schedule device
			 * recognition, the interrupt stays pending. We need to
			 * dynamically allocate an ioinfo structure, etc..
			 */
			if ( ioinfo[irq] == INVALID_STORAGE_AREA )
			{
				return;	/* this keeps the device boxed ... */
			}
	
			irq_enter(cpu, irq);
			s390irq_spin_lock( irq );
			s390_process_IRQ( irq );
			s390irq_spin_unlock( irq );
			irq_exit(cpu, irq);
		}

#ifdef CONFIG_FAST_IRQ

		/*
		 * Are more interrupts pending?
		 * If so, the tpi instruction will update the lowcore 
		 * to hold the info for the next interrupt.
		 */
	} while ( tpi( NULL ) != 0 );

#endif /*  CONFIG_FAST_IRQ */

	return;
}


/*
 * s390_process_IRQ() handles status pending situations and interrupts
 *
 * Called by : do_IRQ()             - for "real" interrupts
 *             s390_start_IO, halt_IO()
 *                                  - status pending cond. after SSCH, or HSCH
 *             disable_subchannel() - status pending conditions (after MSCH)
 *
 * Returns: 0 - no ending status received, no further action taken
 *          1 - interrupt handler was called with ending status
 */
int s390_process_IRQ( unsigned int irq )
{
	int                    ccode;      /* cond code from tsch() operation */
	int                    irb_cc;     /* cond code from irb */
	int                    sdevstat;   /* struct devstat size to copy */
	unsigned int           fctl;       /* function control */
	unsigned int           stctl;      /* status   control */
	unsigned int           actl;       /* activity control */

	int               issense         = 0;
	int               ending_status   = 0;
	int               allow4handler   = 1;
	int               chnchk          = 0;
	devstat_t        *dp;
	devstat_t        *udp;

	char dbf_txt[15];
	char buffer[80];


	if (cio_count_irqs) {
		int cpu = smp_processor_id();
		s390_irq_count[cpu]++;
	}
	
	
	if (cio_debug_initialized) {
		sprintf(dbf_txt, "procIRQ%x", irq);
		debug_text_event(cio_debug_trace_id, 3, dbf_txt);
	}

	if ( ioinfo[irq] == INVALID_STORAGE_AREA )
	{
		/* we can't properly process the interrupt ... */
		tsch( irq, p_init_irb );
		return( 1 );

	} /* endif */

	dp  = &ioinfo[irq]->devstat;
	udp = ioinfo[irq]->irq_desc.dev_id;
	

	/*
	 * It might be possible that a device was not-oper. at the time
	 *  of free_irq() processing. This means the handler is no longer
	 *  available when the device possibly becomes ready again. In
	 *  this case we perform delayed disable_subchannel() processing.
	 */
	if ( !ioinfo[irq]->ui.flags.ready )
	{
		if ( !ioinfo[irq]->ui.flags.d_disable )
		{
#ifdef CONFIG_DEBUG_IO
			printk( KERN_CRIT"s390_process_IRQ(%04X) "
			        "- no interrupt handler registered "
					  "for device %04X !\n",
			        irq,
			        ioinfo[irq]->devstat.devno);
#endif /* CONFIG_DEBUG_IO */
			if (cio_debug_initialized)
				debug_sprintf_event(cio_debug_msg_id, 0,
						    "s390_process_IRQ(%04X) - no interrupt handler registered for device %04X !\n",
						    irq, ioinfo[irq]->devstat.devno);
		} /* endif */

	} /* endif */

	/*
	 * retrieve the i/o interrupt information (irb),
	 *  update the device specific status information
	 *  and possibly call the interrupt handler.
	 *
	 * Note 1: At this time we don't process the resulting
	 *         condition code (ccode) from tsch(), although
	 *         we probably should.
	 *
	 * Note 2: Here we will have to check for channel
	 *         check conditions and call a channel check
	 *         handler.
	 *
	 * Note 3: If a start function was issued, the interruption
	 *         parameter relates to it. If a halt function was
	 *         issued for an idle device, the intparm must not
	 *         be taken from lowcore, but from the devstat area.
	 */
	ccode = tsch( irq, &(dp->ii.irb) );

	if (cio_debug_initialized) {
		sprintf(dbf_txt, "ccode:%d", ccode);
		debug_text_event(cio_debug_trace_id, 3, dbf_txt);
	}

	//
	// We must only accumulate the status if the device is busy already
	//
	if ( ioinfo[irq]->ui.flags.busy )
	{
		dp->dstat   |= dp->ii.irb.scsw.dstat;
		dp->cstat   |= dp->ii.irb.scsw.cstat;
                dp->intparm  = ioinfo[irq]->u_intparm;

	}
	else
	{
		dp->dstat    = dp->ii.irb.scsw.dstat;
		dp->cstat    = dp->ii.irb.scsw.cstat;

		dp->flag     = 0;   // reset status flags
		dp->intparm  = 0;

	} /* endif */

	dp->lpum = dp->ii.irb.esw.esw1.lpum;

	/*
	 * reset device-busy bit if no longer set in irb
	 */
	if (    (dp->dstat & DEV_STAT_BUSY                   ) 
	     && ((dp->ii.irb.scsw.dstat & DEV_STAT_BUSY) == 0))
	{
		dp->dstat &= ~DEV_STAT_BUSY;

	} /* endif */

	/*
	 * Save residual count and CCW information in case primary and
	 *  secondary status are presented with different interrupts.
	 */
	if ( dp->ii.irb.scsw.stctl
	     & ( SCSW_STCTL_PRIM_STATUS | SCSW_STCTL_INTER_STATUS ) ) {

		/*
		 * If the subchannel status shows status pending
		 * and we received a check condition, the count
		 * information is not meaningful.
		 */
		
		 if ( !(    (dp->ii.irb.scsw.stctl & SCSW_STCTL_STATUS_PEND) 
			 && (   dp->ii.irb.scsw.cstat 
			      & (   SCHN_STAT_CHN_DATA_CHK
				  | SCHN_STAT_CHN_CTRL_CHK
				  | SCHN_STAT_INTF_CTRL_CHK
				  | SCHN_STAT_PROG_CHECK
				  | SCHN_STAT_PROT_CHECK
				  | SCHN_STAT_CHAIN_CHECK )))) {

			 dp->rescnt = dp->ii.irb.scsw.count;
		 } else {
			 dp->rescnt = SENSE_MAX_COUNT;
		 }

		dp->cpa    = dp->ii.irb.scsw.cpa;

#ifdef CONFIG_DEBUG_IO
		if ( irq != cons_dev )
			printk( KERN_DEBUG "s390_process_IRQ( %04X ) : "
			        "residual count from irb after tsch() %d\n",
			        irq, dp->rescnt );
#endif
		if (cio_debug_initialized)
			debug_sprintf_event(cio_debug_msg_id, 6,
					    "s390_process_IRQ( %04X ) : residual count from irq after tsch() %d\n",
					    irq, dp->rescnt);

	} /* endif */

	irb_cc = dp->ii.irb.scsw.cc;

	//
	// check for any kind of channel or interface control check but don't
	//  issue the message for the console device
	//
	if (    (dp->ii.irb.scsw.cstat
	            & (  SCHN_STAT_CHN_DATA_CHK
	               | SCHN_STAT_CHN_CTRL_CHK
			 | SCHN_STAT_INTF_CTRL_CHK )))
	{
		if (irq != cons_dev)
			printk( KERN_WARNING "Channel-Check or Interface-Control-Check "
				"received\n"
				" ... device %04X on subchannel %04X, dev_stat "
				": %02X sch_stat : %02X\n",
				ioinfo[irq]->devstat.devno,
				irq,
				dp->dstat,
				dp->cstat);
		if (cio_debug_initialized) {
			debug_sprintf_event(cio_debug_msg_id, 0,
					    "Channel-Check or Interface-Control-Check received\n");
			debug_sprintf_event(cio_debug_msg_id, 0,
					    "... device %04X on subchannel %04X, dev_stat: %02X sch_stat: %02X\n",
					    ioinfo[irq]->devstat.devno, irq, dp->dstat, dp->cstat);
		}

		chnchk = 1;

	} /* endif */

	if( dp->ii.irb.scsw.ectl==0)
	{
		issense=0;
	}
	else if (    (dp->ii.irb.scsw.stctl == SCSW_STCTL_STATUS_PEND)
	          && (dp->ii.irb.scsw.eswf  == 0                     ))
	{
		issense = 0;
	}
	else if (   (dp->ii.irb.scsw.stctl ==
		      (SCSW_STCTL_STATUS_PEND | SCSW_STCTL_INTER_STATUS)) 
		 && ((dp->ii.irb.scsw.actl & SCSW_ACTL_SUSPENDED) == 0)  )
	{
		issense = 0;
	}
	else
	{
		issense = dp->ii.irb.esw.esw0.erw.cons;

	} /* endif */

	if ( issense )
	{
		dp->scnt  = dp->ii.irb.esw.esw0.erw.scnt;
		dp->flag |= DEVSTAT_FLAG_SENSE_AVAIL;
                  	
		sdevstat = sizeof( devstat_t);

#ifdef CONFIG_DEBUG_IO
		if ( irq != cons_dev )
			printk( KERN_DEBUG "s390_process_IRQ( %04X ) : "
			        "concurrent sense bytes avail %d\n",
			        irq, dp->scnt );
#endif
		if (cio_debug_initialized)
			debug_sprintf_event(cio_debug_msg_id, 4,
					    "s390_process_IRQ( %04X ): concurrent sense bytes avail %d\n",
					    irq, dp->scnt);
	}
	else
	{
		/* don't copy the sense data area ! */
		sdevstat = sizeof( devstat_t) - SENSE_MAX_COUNT;

	} /* endif */

	switch ( irb_cc ) {
	case 1:      /* status pending */

		dp->flag |= DEVSTAT_STATUS_PENDING;

	case 0:      /* normal i/o interruption */

		fctl  = dp->ii.irb.scsw.fctl;
		stctl = dp->ii.irb.scsw.stctl;
		actl  = dp->ii.irb.scsw.actl;

		if ( chnchk )
		{
			sprintf( buffer, "s390_process_IRQ(%04X) - irb for "
			         "device %04X after channel check\n",
			         irq,
			         dp->devno );

			s390_displayhex( buffer,
			                 &(dp->ii.irb) ,
			                 sizeof(irb_t));
			if (cio_debug_initialized) {
				
				sp