s390io.c

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	     && ( sync_isc_locked                ) )
	{
		disable_cpu_sync_isc( irq );

		spin_unlock_irqrestore( &sync_isc, psw_flags);

		sync_isc_locked              = 0;    // local setting
		ioinfo[irq]->ui.flags.syncio = 0;    // global setting

	} /* endif */

	return( ret);
}

int do_IO( int            irq,          /* IRQ */
           ccw1_t        *cpa,          /* channel program address */
           unsigned long  user_intparm, /* interruption parameter */
           __u8           lpm,          /* logical path mask */
           unsigned long  flag)         /* flags : see above */
{
	int ret = 0;

	if ( irq > highest_subchannel || irq < 0 )
	{
		return( -ENODEV );

	} /* endif */

	if ( ioinfo[irq] == INVALID_STORAGE_AREA )
	{
		return( -ENODEV);
   }

	/* handler registered ? or free_irq() in process already ? */
	if ( !ioinfo[irq]->ui.flags.ready || ioinfo[irq]->ui.flags.unready )
	{
		return( -ENODEV );

	} /* endif */

	/*
	 * Note: We ignore the device operational status - if not operational,
	 *        the SSCH will lead to an -ENODEV condition ...
	 */
	if ( !ioinfo[irq]->ui.flags.busy )         /* last I/O completed ? */
	{
		ret = s390_start_IO( irq, cpa, user_intparm, lpm, flag);
	}
	else if ( ioinfo[irq]->ui.flags.fast )
	{
		/*
		 * If primary status was received and ending status is missing,
		 *  the device driver won't be notified on the ending status
		 *  if early (fast) interrupt notification was requested.
		 *  Therefore we have to queue the next incoming request. If
		 *  halt_IO() is issued while there is a request queued, a HSCH
		 *  needs to be issued and the queued request must be deleted
		 *  but its intparm must be returned (see halt_IO() processing)
		 */
		if (     ioinfo[irq]->ui.flags.w4final
           && !ioinfo[irq]->ui.flags.doio_q )
		{
			ioinfo[irq]->qflag    = flag;
			ioinfo[irq]->qcpa     = cpa;
			ioinfo[irq]->qintparm = user_intparm;
			ioinfo[irq]->qlpm     = lpm;
		}
		else
		{
			ret = -EBUSY;

		} /* endif */
	}
	else
	{
		ret = -EBUSY;

	} /* endif */

	return( ret );

}

/*
 * resume suspended I/O operation
 */
int resume_IO( int irq)
{
	int ret = 0;

	if ( irq > highest_subchannel || irq < 0 )
	{
		return( -ENODEV );

	} /* endif */

	if ( ioinfo[irq] == INVALID_STORAGE_AREA )
	{
		return( -ENODEV);
   }

	/*
	 * We allow for 'resume' requests only for active I/O operations
	 */
	if ( ioinfo[irq]->ui.flags.busy )
	{
		int ccode;

		ccode = rsch( irq);

		switch (ccode) {
		case 0 :
			break;

		case 1 :
		  	s390_process_IRQ( irq );
			ret = -EBUSY;
			break;

		case 2 :
			ret = -EINVAL;
			break;

		case 3 :
			/*
			 * useless to wait for request completion
			 *  as device is no longer operational !
			 */
			ioinfo[irq]->ui.flags.oper = 0;
			ioinfo[irq]->ui.flags.busy = 0;
			ret                        = -ENODEV;
			break;

		} /* endswitch */          	
		
	}
	else
	{
		ret = -ENOTCONN;

	} /* endif  */

	return( ret);
}

/*
 * Note: The "intparm" parameter is not used by the halt_IO() function
 *       itself, as no ORB is built for the HSCH instruction. However,
 *       it allows the device interrupt handler to associate the upcoming
 *       interrupt with the halt_IO() request.
 */
int halt_IO( int           irq,
             unsigned long user_intparm,
             unsigned long flag)  /* possible DOIO_WAIT_FOR_INTERRUPT */
{
	int            ret;
	int            ccode;
	unsigned long  psw_flags;

	int            sync_isc_locked = 0;

	if ( irq > highest_subchannel || irq < 0 )
	{
		ret = -ENODEV;
	}

	if ( ioinfo[irq] == INVALID_STORAGE_AREA )
	{
		return( -ENODEV);
   }

	/*
	 * we only allow for halt_IO if the device has an I/O handler associated
	 */
	else if ( !ioinfo[irq]->ui.flags.ready )
	{
		ret = -ENODEV;
	}
	/*
	 * we ignore the halt_io() request if ending_status was received but
	 *  a SENSE operation is waiting for completion.
	 */
	else if ( ioinfo[irq]->ui.flags.w4sense )
	{
		ret = 0;
	}
	/*
	 * We don't allow for halt_io with a sync do_IO() requests pending.
	 */
	else if ( ioinfo[irq]->ui.flags.syncio )
	{
		ret = -EBUSY;
	}
	else
	{
		/*
		 * 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 )
		{
			//
			// check whether we run recursively (sense processing)
			//
			if ( !ioinfo[irq]->ui.flags.syncio )
			{
				spin_lock_irqsave( &sync_isc, psw_flags);
  	
				ret = enable_cpu_sync_isc( irq);

				if ( ret )
				{
					spin_unlock_irqrestore( &sync_isc,
					                        psw_flags);
					return( ret);
				}
				else
				{
					sync_isc_locked              = 1; // local
					ioinfo[irq]->ui.flags.syncio = 1; // global

				} /* endif */  	
  	
			} /* endif */

		} /* endif */

		/*
		 * Issue "Halt subchannel" and process condition code
		 */
		ccode = hsch( irq );

		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_HALT_FUNCTION;
				ioinfo[irq]->devstat.scnt    = 0;

			}
			else
			{
				ioinfo[irq]->devstat.flag   |= DEVSTAT_HALT_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( "halt_IO() : unexpected "
					       "address-space-control %d\n",
					       ccode);
					break;
				} /* endswitch */

				io_sync_wait.addr = FIX_PSW(&&hio_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
				{

	      		asm volatile ( "lpsw %0" : : "m" (io_sync_wait) );
hio_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 :            /* status pending */
	
			ioinfo[irq]->devstat.flag |= DEVSTAT_STATUS_PENDING;

			/*
			 * initialize the device driver specific devstat irb area
			 */
			memset( &((devstat_t *) ioinfo[irq]->irq_desc.action->dev_id)->ii.irb,
			        '\0', sizeof( irb_t) );

			/*
			 * Let the common interrupt handler process the pending
			 *  status. However, we must avoid calling the user
			 *  action handler, as it won't be prepared to handle
                        *  a pending status during do_IO() processing inline.
			 *  This also implies that s390_process_IRQ must
			 *  terminate synchronously - especially if device
			 *  sensing is required.
			 */
			ioinfo[irq]->ui.flags.s_pend   = 1;
			ioinfo[irq]->ui.flags.busy     = 1;
			ioinfo[irq]->ui.flags.doio     = 1;

			s390_process_IRQ( irq );
			
			ioinfo[irq]->ui.flags.s_pend   = 0;
			ioinfo[irq]->ui.flags.busy     = 0;
			ioinfo[irq]->ui.flags.doio     = 0;
			ioinfo[irq]->ui.flags.repall   = 0;
			ioinfo[irq]->ui.flags.w4final  = 0;

			ioinfo[irq]->devstat.flag     |= DEVSTAT_FINAL_STATUS;

			/*
			 * In multipath mode a condition code 3 implies the last
			 *  path has gone, except we have previously restricted
			 *  the I/O to a particular path. A condition code 1
			 *  (0 won't occur) results in return code EIO as well
			 *  as 3 with another path than the one used (i.e. path available mask is non-zero).
			 */
			if ( ioinfo[irq]->devstat.ii.irb.scsw.cc == 3 )
			{
				ret                         = -ENODEV;
				ioinfo[irq]->devstat.flag  |= DEVSTAT_NOT_OPER;
				ioinfo[irq]->ui.flags.oper  = 0;
			}
			else
			{
				ret                         = -EIO;
				ioinfo[irq]->devstat.flag  &= ~DEVSTAT_NOT_OPER;
				ioinfo[irq]->ui.flags.oper  = 1;

			} /* endif */

			break;

		case 2 :            /* busy */

			ret = -EBUSY;
			break;

		default:            /* device not operational */

			ret = -ENODEV;
			break;

		} /* endswitch */

		if (    ( flag & DOIO_WAIT_FOR_INTERRUPT )
	   	  && ( sync_isc_locked                ) )
		{
			sync_isc_locked              = 0;    // local setting
		   ioinfo[irq]->ui.flags.syncio = 0;    // global setting
  	
			disable_cpu_sync_isc( irq );
  	
			spin_unlock_irqrestore( &sync_isc, psw_flags);
  	
		} /* endif */

	} /* endif */

	return( ret );
}

/*
 * Note: The "intparm" parameter is not used by the clear_IO() function
 *       itself, as no ORB is built for the CSCH instruction. However,
 *       it allows the device interrupt handler to associate the upcoming
 *       interrupt with the clear_IO() request.
 */
int clear_IO( int           irq,
              unsigned long user_intparm,
              unsigned long flag)  /* possible DOIO_WAIT_FOR_INTERRUPT */
{
	int            ret;
	int            ccode;
	unsigned long  psw_flags;

	int            sync_isc_locked = 0;

	if ( irq > highest_subchannel || irq < 0 )
	{
		ret = -ENODEV;
	}

	if ( ioinfo[irq] == INVALID_STORAGE_AREA )
	{
		return( -ENODEV);
   }

	/*
	 * we only allow for halt_IO if the device has an I/O handler associated
	 */
	else if ( !ioinfo[irq]->ui.flags.ready )
	{
		ret = -ENODEV;
	}
	/*
	 * we ignore the halt_io() request if ending_status was received but
	 *  a SENSE operation is waiting for completion.
	 */
	else if ( ioinfo[irq]->ui.flags.w4sense )
	{
		ret = 0;
	}
	/*
	 * We don't allow for halt_io with a sync do_IO() requests pending.
	 *  Concurrent I/O is possible in SMP environments only, but the
	 *  sync. I/O request can be gated to one CPU at a time only.
	 */
	else if ( ioinfo[irq]->ui.flags.syncio )
	{
		ret = -EBUSY;
	}
	else
	{
		/*
		 * 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 )
		{
			//
			// check whether we run recursively (sense processing)
			//
			if ( !ioinfo[irq]->ui.flags.syncio )
			{
				spin_lock_irqsave( &sync_isc, psw_flags);
  	
				ret = enable_cpu_sync_isc( irq);

				if ( ret )
				{
					spin_unlock_irqrestore( &sync_isc,
					                        psw_flags);
					return( ret);
				}
				else
				{
					sync_isc_locked              = 1; // local
					ioinfo[irq]->ui.flags.syncio = 1; // global

				} /* endif */  	
  	
			} /* endif */

		} /* endif */

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

		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;