msi_lpmaint.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

     * involved in requesting resetting of a remote port and system are as
     * follows:
     *
     * 1. Lock the PCCB.
     * 2. Verify operational status of the local port and validity of the
     *    target remote port station address.
     * 3. Allocate a MSI port command packet.
     * 4. Format the MSIB buffer.
     * 5. Insert the MSIB buffer onto the appropriate command queue.
     * 6. Request the XFP to process outgoing MSI packets.
     * 7. Unlock the PCCB.
     *
     * Requests to reset the local port and system are always satisfied without
     * transmitting an RST packet( Step 2 ) and without performing the actual
     * reset.  Resets of the local port and system have no meaning in the
     * current context.
     *
     * Formatting the MSIB buffer( Step 4 ) consists of formatting the:
     *
     * MSIB buffer header - information needed by XFP for packet transmission
     * MSI port header    - common MSI packet fields
     * MSI packet body	  - RST specific MSI packet fields
     *
     * RST specific MSI packet fields requiring formatting by this routine
     * include only the transaction identifier.  This field is currently always
     * set to 0.  Also, the appropriate bit is set in the MSI port header flags
     * field whenever resetting of the remote port and system is to be forced.
     *
     * MSIB buffers containing reset requests are always inserted onto the
     * appropriate low priority command queue( Step 5 ).  The PCCB specific
     * COMQL is locked immediately prior to insertion and unlocked immediately
     * afterwards.  This guarantees exclusive access to the queue.
     *
     * The XFP is requested to begin processing of outgoing MSI packets( Step
     * 6 ) by scheduling its asynchronous execution.  This step is bypassed
     * whenever XFP execution has already been scheduled but has not yet
     * commenced.  During XFP scheduling the PCCB lock guarantees the existence
     * of only 1 scheduled asynchronous XFP thread at any given moment.
     *
     * NOTE:	It is possible for a XFP thread to be currently active.  This
     *		does not prevent scheduling of asynchronous XFP execution.
     *		However, the new thread does not begin to process outgoing MSI
     *		packets until the currently active thread completes.  Also, no
     *		other additional XFP threads are scheduled until the new thread
     *		begins processing outgoing MSI packets.
     */
    Lock_pccb( pccb )
    if( !pccb->Fsmstatus.online ) {
	status = RET_INVLPSTATE;
    } else if( Scaaddr_lob( *rport ) > pccb->lpinfo.Max_port ) {
	status = RET_NOPATH;
    } else if( Scaaddr_lob( *rport ) != Scaaddr_lob( pccb->lpinfo.addr )){
	if(( msibp = msi_alloc_pkt( pccb ))) {
	    Format_msibh( msibp, rport->low, sizeof( MSI_RST ), DEALLOC_BUF )
	    Format_msih( msibp, RST )
	    msibp->Ph.flags.Freset = force;
	    Format_rst( msibp )
	    Insert_comql( pccb, msibp )
	    Xstart_xfp( pccb )
	} else {
	    status = RET_ALLOCFAIL;
	}
    }
    Unlock_pccb( pccb )
    return( status );
}

/*   Name:	msi_remote_strt - Start Remote Port and System
 *
 *   Abstract:	This function initiates the starting of a remote MSI port and
 *		system.  The remote system need NOT be known to be started;
 *		however, the local port must have previously reset the remote
 *		port for it to start it.
 *
 *		Initiating starting of a remote port and system is accomplished
 *		by initiating transmission of a MSI port specific STRT packet
 *		to the target remote port.  A MSI port command packet is used
 *		to contain the start request.  It is allocated by this function
 *		and deallocated following packet transmission.
 *
 *		A start address can be optionally supplied; otherwise, the
 *		default start address is used.
 *
 *              NOTE: SCA port numbers are 6 bytes in size; however, maximum
 *                    MSI port numbers only occupy 1 byte.
 *
 *		NOTE: All attempts to transmit packets to the local ports own
 *		      station address are bypassed.  The SII chip is not
 *		      capable of either internal loopback or simultaneous
 *		      transmission and reception; and, no need exists to
 *		      provide this function in software.
 *
 *   Inputs:
 *
 *   IPL_SCS			- Interrupt processor level
 *   pccb			- Port Command and Control Block pointer
 *   rport			- Station address of target remote port
 *   start_addr			- Start address( OPTIONAL )
 *
 *   Outputs:
 *
 *   IPL_SCS			- Interrupt processor level
 *   pccb			- Port Command and Control Block pointer
 *	pd.msi			-  MSI specific PCCB fields
 *	    comql		-   MSIB low priority command queue
 *	    lpstatus.xfork	-   1
 *	    xforkb		-   Transmit Fork Process fork block
 *
 *   Return Values:
 *
 *   RET_SUCCESS		- Transmission successfully initiated
 *   RET_ALLOCFAIL		- Failed to allocate command packet
 *   RET_INVLPSTATE		- Local port in invalid state
 *   RET_NOPATH			- Invalid remote port station address
 *
 *   SMP:       The PCCB is locked allowing exclusive access to PCCB contents.
 *              PCCB addresses are always valid because these data structures
 *              are never deleted once their corresponding ports have been
 *		initialized.
 *
 *		The PCCB specific COMQL is locked allowing exclusive access to
 *		the corresponding low priority command queue
 */
u_long
msi_remote_strt( pccb, rport, start_addr )
    register PCCB	*pccb;
    scaaddr		*rport;
    u_long		start_addr;
{
    register MSIB	*msibp;
    register u_long	status = RET_SUCCESS;

    /* Only the Transmit Fork Process( XFP ) interfaces directly with the SII
     * chip for the purpose of processing outgoing MSI packets.  All other
     * driver routines must interface with the XFP.  Therefore the steps
     * involved in requesting starting of a remote port and system are as
     * follows:
     *
     * 1. Lock the PCCB.
     * 2. Verify operational status of the local port and validity of the
     *    target remote port station address.
     * 3. Allocate a MSI port command packet.
     * 4. Format the MSIB buffer.
     * 5. Insert the MSIB buffer onto the appropriate port command queue.
     * 6. Request the XFP to process outgoing MSI packets.
     * 7. Unlock the PCCB.
     *
     * Requests to start the local port and system are always satisfied without
     * transmitting an STRT packet( Step 2 ) and without performing the actual
     * start.  Starts of the local port and system have no meaning in the
     * current context.
     *
     * Formatting the MSIB buffer( Step 4 ) consists of formatting the:
     *
     * MSIB buffer header - information needed by XFP for packet transmission
     * MSI port header    - common MSI packet fields
     * MSI packet body	  - STRT specific MSI packet fields
     *
     * STRT specific MSI packet fields requiring formatting by this routine
     * include the transaction identifier and the start address.  The former is
     * currently always set to 0.  Also, the appropriate bit is set in the MSI
     * port header flags field whenever the remote port and system is to be
     * started at its default start address.
     *
     * MSIB buffers containing start requests are always inserted onto the
     * appropriate low priority command queue( Step 5 ).  The PCCB specific
     * COMQL is locked immediately prior to insertion and unlocked immediately
     * afterwards.  This guarantees exclusive access to the queue.
     *
     * The XFP is requested to begin processing of outgoing MSI packets( Step
     * 6 ) by scheduling its asynchronous execution.  This step is bypassed
     * whenever XFP execution has already been scheduled but has not yet
     * commenced.  During XFP scheduling the PCCB lock guarantees the existence
     * of only 1 scheduled asynchronous XFP thread at any given moment.
     *
     * NOTE:	It is possible for a XFP thread to be currently active.  This
     *		does not prevent scheduling of asynchronous XFP execution.
     *		However, the new thread does not begin to process outgoing MSI
     *		packets until the currently active thread completes.  Also, no
     *		other additional XFP threads are scheduled until the new thread
     *		begins processing outgoing MSI packets.
     */
    Lock_pccb( pccb )
    if( !pccb->Fsmstatus.online ) {
	status = RET_INVLPSTATE;
    } else if( Scaaddr_lob( *rport ) > pccb->lpinfo.Max_port ) {
	status = RET_NOPATH;
    } else if( Scaaddr_lob( *rport ) != Scaaddr_lob( pccb->lpinfo.addr )){
	if(( msibp = msi_alloc_pkt( pccb ))) {
	    Format_msibh( msibp, rport->low, sizeof( MSI_STRT ), DEALLOC_BUF )
	    Format_msih( msibp, STRT )
	    msibp->Ph.flags.Dsa = (( start_addr == 0 ) ? 1: 0 );
	    Format_strt( msibp, start_addr )
	    Insert_comql( pccb, msibp )
	    Xstart_xfp( pccb )
	} else {
	    status = RET_ALLOCFAIL;
	}
    }
    Unlock_pccb( pccb )
    return( status );
}

/*   Name:	msi_shutdown	- Inform Known Systems of Local Shutdown
 *
 *   Abstract:	This routine informs systems known through paths originating
 *		at a specific local MSI port of local system shutdown.  This is
 *		accomplished through disabling of the specified port.  The
 *		remote system discovers the unavailability of the port either
 *		during CI PPD polling or during utilization of the virtual
 *		circuit.  At that time it terminates its path to the port and
 *		and thus to the local system.
 *
 *		NOTE: STOP CI PPD datagrams are not transmitted across all
 *		      formative and established paths.  This is because the
 *		      state of the port is unknown and may in fact preclude
 *		      datagram transmission.
 *
 *   Inputs:
 *
 *   IPL_POWER			- Interrupt processor level
 *   pccb			- Port Command and Control Block pointer
 *
 *   Outputs:
 *   pccb			- Port Command and Control Block pointer
 *	ppd.cippd		-  CI PPD specific PCCB fields
 *	    fsmstatus.online	-   0
 *
 *   IPL_POWER			- Interrupt processor level
 *
 *   SMP:       No locks are required.  This routine is only called(
 *		indirectly ) from panic() and it is invoked at maximum IPL.
 *		Only the processor executing this code is operational and this
 *              routine can not be interrupted on this processor.  This
 *              guarantees uncompromised access to the PCCB without locking it.
 */
void
msi_shutdown( pccb )
    PCCB		*pccb;
{
    /* Local port disablement is accomplished through invocation of the
     * appropriate routine.  The local port is taken explicitly offline prior
     * to disablement.  This aborts all CI PPD port polling on the local port.
     */
    pccb->Fsmstatus.online = 0;
    ( void )msi_disable( pccb );
}