acornscsi.c.dag2

arm平台上的uclinux系统全部源代码

 */
static
unsigned char acornscsi_readmessagebyte (AS_Host *host)
{
    unsigned char message;

    acornscsi_sbic_issuecmd (host, CMND_XFERINFO | CMND_SBT);
    while ((sbic_arm_read (host->scsi.io_port, ASR) & ASR_DBR) == 0);

    message = sbic_arm_read (host->scsi.io_port, DATA);

    /* wait for MSGIN-XFER-PAUSED */
    while ((sbic_arm_read (host->scsi.io_port, ASR) & ASR_INT) == 0);
    sbic_arm_read (host->scsi.io_port, SSR);

    return message;
}

/*
 * Function: void acornscsi_message (AS_Host *host)
 * Purpose : Read complete message from connected target & action message
 * Params  : host - host connected to target
 */
static
void acornscsi_message (AS_Host *host)
{
    unsigned char message[16];
    unsigned int msgidx = 0, msglen = 1;

    do {
	message[msgidx] = acornscsi_readmessagebyte (host);

	switch (msgidx) {
	case 0:
	    if (message[0] == EXTENDED_MESSAGE ||
		(message[0] >= 0x20 && message[0] <= 0x2f))
		msglen = 2;
	    break;

	case 1:
	    if (message[0] == EXTENDED_MESSAGE)
		msglen += message[msgidx];
	    break;
	}
	msgidx += 1;
	if (msgidx < msglen) {
	    acornscsi_sbic_issuecmd (host, CMND_NEGATEACK);

	    /* wait for next msg-in */
	    while ((sbic_arm_read (host->scsi.io_port, ASR) & ASR_INT) == 0);
	    sbic_arm_read (host->scsi.io_port, SSR);
	}
    } while (msgidx < msglen);

#if (DEBUG & DEBUG_MESSAGES)
    printk (KERN_DEBUG "scsi%d.%c: message in: ",
	    host->host->host_no, acornscsi_target (host));
    print_msg (message);
    printk ("\n");
#endif

    if (host->scsi.phase == PHASE_RECONNECTED) {
	/*
	 * ANSI standard says: (Section SCSI-2 Rev. 10c Sect 5.6.17)
	 * 'Whenever a target reconnects to an initiator to continue
	 *  a tagged I/O process, the SIMPLE QUEUE TAG message shall
	 *  be sent immediately following the IDENTIFY message...'
	 */
	if (message[0] == SIMPLE_QUEUE_TAG)
	    host->scsi.reconnected.tag = message[1];
	if (acornscsi_reconnect_finish (host))
	    host->scsi.phase = PHASE_MSGIN;
    }

    switch (message[0]) {
    case ABORT:
    case ABORT_TAG:
    case COMMAND_COMPLETE:
	if (host->scsi.phase != PHASE_STATUSIN)
	    printk (KERN_ERR "scsi%d.%c: command complete following non-status in phase?\n",
		    host->host->host_no, acornscsi_target (host));
	host->scsi.phase = PHASE_DONE;
	host->scsi.SCp.Message = message[0];
	break;

    case SAVE_POINTERS:
	/*
	 * ANSI standard says: (Section SCSI-2 Rev. 10c Sect 5.6.20)
	 * 'The SAVE DATA POINTER message is sent from a target to
	 *  direct the initiator to copy the active data pointer to
	 *  the saved data pointer for the current I/O process.
	 */
	acornscsi_dma_cleanup (host);
	host->SCpnt->SCp = host->scsi.SCp;
	host->SCpnt->SCp.sent_command = 0;
	host->scsi.phase = PHASE_MSGIN;
	break;

    case RESTORE_POINTERS:
	/*
	 * ANSI standard says: (Section SCSI-2 Rev. 10c Sect 5.6.19)
	 * 'The RESTORE POINTERS message is sent from a target to
	 *  direct the initiator to copy the most recently saved
	 *  command, data, and status pointers for the I/O process
	 *  to the corresponding active pointers.  The command and
	 *  status pointers shall be restored to the beginning of
	 *  the present command and status areas.'
	 */
	acornscsi_dma_cleanup (host);
	host->scsi.SCp = host->SCpnt->SCp;
	host->scsi.phase = PHASE_MSGIN;
	break;

    case DISCONNECT:
	/*
	 * ANSI standard says: (Section SCSI-2 Rev. 10c Sect 6.4.2)
	 * 'On those occasions when an error or exception condition occurs
	 *  and the target elects to repeat the information transfer, the
	 *  target may repeat the transfer either issuing a RESTORE POINTERS
	 *  message or by disconnecting without issuing a SAVE POINTERS
	 *  message.  When reconnection is completed, the most recent
	 *  saved pointer values are restored.'
	 */
	acornscsi_dma_cleanup (host);
	host->scsi.phase = PHASE_DISCONNECT;
	break;

    case MESSAGE_REJECT:
#if 0 /* this isn't needed any more */
	/*
	 * If we were negociating sync transfer, we don't yet know if
	 * this REJECT is for the sync transfer or for the tagged queue/wide
	 * transfer.  Re-initiate sync transfer negociation now, and if
	 * we got a REJECT in response to SDTR, then it'll be set to DONE.
	 */
	if (host->device[host->SCpnt->target].sync_state == SYNC_SENT_REQUEST)
	    host->device[host->SCpnt->target].sync_state = SYNC_NEGOCIATE;
#endif

	/*
	 * If we have any messages waiting to go out, then assert ATN now
	 */
	if (msgqueue_msglength (&host->scsi.msgs))
	    acornscsi_sbic_issuecmd (host, CMND_ASSERTATN);

	switch (host->scsi.last_message) {
#ifdef SCSI2_TAG
	case HEAD_OF_QUEUE_TAG:
	case ORDERED_QUEUE_TAG:
	case SIMPLE_QUEUE_TAG:
	    /*
	     * ANSI standard says: (Section SCSI-2 Rev. 10c Sect 5.6.17)
	     *  If a target does not implement tagged queuing and a queue tag
	     *  message is received, it shall respond with a MESSAGE REJECT
	     *  message and accept the I/O process as if it were untagged.
	     */
	    printk (KERN_NOTICE "scsi%d.%c: disabling tagged queueing\n",
		    host->host->host_no, acornscsi_target (host));
	    host->SCpnt->device->tagged_queue = 0;
	    set_bit (host->SCpnt->target * 8 + host->SCpnt->lun, &host->busyluns);
	    break;
#endif
	case EXTENDED_MESSAGE | (EXTENDED_SDTR << 8):
	    /*
	     * Target can't handle synchronous transfers
	     */
	    printk (KERN_NOTICE "scsi%d.%c: Using asynchronous transfer\n",
		    host->host->host_no, acornscsi_target (host));
	    host->device[host->SCpnt->target].sync_xfer = SYNCHTRANSFER_2DBA;
	    host->device[host->SCpnt->target].sync_state = SYNC_ASYNCHRONOUS;
	    sbic_arm_write (host->scsi.io_port, SYNCHTRANSFER, host->device[host->SCpnt->target].sync_xfer);
	    break;

	default:
	    break;
	}
	break;

    case QUEUE_FULL:
	/* TODO: target queue is full */
	break;

    case SIMPLE_QUEUE_TAG:
	/* tag queue reconnect... message[1] = queue tag.  Print something to indicate something happened! */
	printk ("scsi%d.%c: reconnect queue tag %02X\n",
		host->host->host_no, acornscsi_target (host),
		message[1]);
	break;

    case EXTENDED_MESSAGE:
	switch (message[2]) {
#ifdef SCSI2_SYNC
	case EXTENDED_SDTR:
	    if (host->device[host->SCpnt->target].sync_state == SYNC_SENT_REQUEST) {
		/*
		 * We requested synchronous transfers.  This isn't quite right...
		 * We can only say if this succeeded if we proceed on to execute the
		 * command from this message.  If we get a MESSAGE PARITY ERROR,
		 * and the target retries fail, then we fallback to asynchronous mode
		 */
		host->device[host->SCpnt->target].sync_state = SYNC_COMPLETED;
		printk (KERN_NOTICE "scsi%d.%c: Using synchronous transfer, offset %d, %d ns\n",
			host->host->host_no, acornscsi_target(host),
			message[4], message[3] * 4);
		host->device[host->SCpnt->target].sync_xfer =
			calc_sync_xfer (message[3] * 4, message[4]);
	    } else {
		unsigned char period, length;
		/*
		 * Target requested synchronous transfers.  The agreement is only
		 * to be in operation AFTER the target leaves message out phase.
		 */
		acornscsi_sbic_issuecmd (host, CMND_ASSERTATN);
		period = max (message[3], sdtr_period / 4);
		length = min (message[4], sdtr_size);
		msgqueue_addmsg (&host->scsi.msgs, 5, EXTENDED_MESSAGE, 3,
				 EXTENDED_SDTR, period, length);
		host->device[host->SCpnt->target].sync_xfer =
			calc_sync_xfer (period * 4, length);
	    }
	    sbic_arm_write (host->scsi.io_port, SYNCHTRANSFER, host->device[host->SCpnt->target].sync_xfer);
	    break;
#else
	    /* We do not accept synchronous transfers.  Respond with a
	     * MESSAGE_REJECT.
	     */
#endif

	case EXTENDED_WDTR:
	    /* The WD33C93A is only 8-bit.  We respond with a MESSAGE_REJECT
	     * to a wide data transfer request.
	     */
	default:
	    acornscsi_sbic_issuecmd (host, CMND_ASSERTATN);
	    msgqueue_flush (&host->scsi.msgs);
	    msgqueue_addmsg (&host->scsi.msgs, 1, MESSAGE_REJECT);
	    break;
	}
	break;

#ifdef SCSI2_LINK
    case LINKED_CMD_COMPLETE:
    case LINKED_FLG_CMD_COMPLETE:
	/*
	 * We don't support linked commands yet
	 */
	if (0) {
#if (DEBUG & DEBUG_LINK)
	    printk (KERN_DEBUG "scsi%d.%c: lun %d tag %d linked command complete\n",
		    host->host->host_no, acornscsi_target(host), host->SCpnt->tag);
#endif
	    /*
	     * A linked command should only terminate with one of these messages
	     * if there are more linked commands available.
	     */
	    if (!host->SCpnt->next_link) {
		printk (KERN_WARNING "scsi%d.%c: lun %d tag %d linked command complete, but no next_link\n",
			instance->host_no, acornscsi_target (host), host->SCpnt->tag);
		acornscsi_sbic_issuecmd (host, CMND_ASSERTATN);
		msgqueue_addmsg (&host->scsi.msgs, 1, ABORT);
	    } else {
		Scsi_Cmnd *SCpnt = host->SCpnt;

		acornscsi_dma_cleanup (host);

		host->SCpnt = host->SCpnt->next_link;
		host->SCpnt->tag = SCpnt->tag;
		SCpnt->result = DID_OK | host->scsi.SCp.Message << 8 | host->Scsi.SCp.Status;
		SCpnt->done (SCpnt);

		/* initialise host->SCpnt->SCp */
	    }
	    break;
	}
#endif

    default: /* reject message */
	printk (KERN_ERR "scsi%d.%c: unrecognised message %02X, rejecting\n",
		host->host->host_no, acornscsi_target (host),
		message[0]);
	acornscsi_sbic_issuecmd (host, CMND_ASSERTATN);
	msgqueue_flush (&host->scsi.msgs);
	msgqueue_addmsg (&host->scsi.msgs, 1, MESSAGE_REJECT);
	host->scsi.phase = PHASE_MSGIN;
	break;
    }
    acornscsi_sbic_issuecmd (host, CMND_NEGATEACK);
}

/*
 * Function: int acornscsi_buildmessages (AS_Host *host)
 * Purpose : build the connection messages for a host
 * Params  : host - host to add messages to
 */
static
void acornscsi_buildmessages (AS_Host *host)
{
#if 0
    /* does the device need resetting? */
    if (cmd_reset) {
	msgqueue_addmsg (&host->scsi.msgs, 1, BUS_DEVICE_RESET);
	return;
    }
#endif

    msgqueue_addmsg (&host->scsi.msgs, 1,
		     IDENTIFY(host->device[host->SCpnt->target].disconnect_ok,
			     host->SCpnt->lun));

#if 0
    /* does the device need the current command aborted */
    if (cmd_aborted) {
	acornscsi_abortcmd (host->SCpnt->tag);
	return;
    }
#endif

#ifdef SCSI2_TAG
    if (host->SCpnt->tag) {
	unsigned int tag_type;

	if (host->SCpnt->cmnd[0] == REQUEST_SENSE ||
	    host->SCpnt->cmnd[0] == TEST_UNIT_READY ||
	    host->SCpnt->cmnd[0] == INQUIRY)
	    tag_type = HEAD_OF_QUEUE_TAG;
	else
	    tag_type = SIMPLE_QUEUE_TAG;
	msgqueue_addmsg (&host->scsi.msgs, 2, tag_type, host->SCpnt->tag);
    }
#endif

#ifdef SCSI2_SYNC
    if (host->device[host->SCpnt->target].sync_state == SYNC_NEGOCIATE) {
	host->device[host->SCpnt->target].sync_state = SYNC_SENT_REQUEST;
	msgqueue_addmsg (&host->scsi.msgs, 5,
			 EXTENDED_MESSAGE, 3, EXTENDED_SDTR,
			 sdtr_period / 4, sdtr_size);
    }
#endif
}

/*
 * Function: int acornscsi_starttransfer (AS_Host *host)
 * Purpose : transfer data to/from connected target
 * Params  : host - host to which target is connected
 * Returns : 0 if failure
 */
static
int acornscsi_starttransfer (AS_Host *host)
{
    int residual;

    if (!host->scsi.SCp.ptr /*&& host->scsi.SCp.this_residual*/) {
	printk (KERN_ERR "scsi%d.%c: null buffer passed to acornscsi_starttransfer\n",
		host->host->host_no, acornscsi_target (host));
	return 0;
    }

    residual = host->SCpnt->request_bufflen - host->scsi.SCp.have_data_in;

    sbic_arm_write (host->scsi.io_port, SYNCHTRANSFER, host->device[host->SCpnt->target].sync_xfer);
    sbic_arm_writenext (host->scsi.io_port, residual >> 16);
    sbic_arm_writenext (host->scsi.io_port, residual >> 8);
    sbic_arm_writenext (host->scsi.io_port, residual);
    acornscsi_sbic_issuecmd (host, CMND_XFERINFO);
    return 1;
}

/* =========================================================================================
 * Connection & Disconnection
 */
/*
 * Function : acornscsi_reconnect (AS_Host *host)
 * Purpose  : reconnect a previously disconnected command
 * Params   : host - host specific data
 * Remarks  : SCSI spec says:
 *		'The set of active pointers is restored from the set
 *		 of saved pointers upon reconnection of the I/O process'
 */
static
int acornscsi_reconnect (AS_Host *host)
{
    unsigned int target, lun, ok = 0;

    target = sbic_arm_read (host->scsi.io_port, SOURCEID);

    if (!(target & 8))
	printk (KERN_ERR "scsi%d: invalid source id after reselection "
		"- device fault?\n",
		host->host->host_no);

    target &= 7;

    if (host->SCpnt && !host->scsi.disconnectable) {
	printk (KERN_ERR "scsi%d.%d: reconnected while command in "
		"progress to target %d?\n",
		host->host->host_no, target, host->SCpnt->target);
	host->SCpnt = NULL;
    }

    lun = sbic_arm_read (host->scsi.io_port, DATA) & 7;

    host->scsi.reconnected.target = target;
    host->scsi.reconnected.lun = lun;
    host->scsi.reconnected.tag = 0;

    if (host->scsi.disconnectable && host->SCpnt &&
	host->SCpnt->target == target && host->SCpnt->lun == lun)
	ok = 1;

    if (!ok && queue_probetgtlun (&host->queues.disconnected, target, lun))
	ok = 1;

    ADD_STATUS(target, 0x81, host->scsi.phase, 0);

    if (ok) {
	host->scsi.phase = PHASE_RECONNECTED;
    } else {
	/* this doesn't seem to work */
	printk (KERN_ERR "scsi%d.%c: reselected with no command "
		"to reconnect with\n",
		host->host->host_no, '0' + target);
	acornscsi_dumplog (host, target);
	acornscsi_sbic_issuecmd (host, CMND_ASSERTATN);
	msgqueue_addmsg (&host->scsi.msgs, 1, ABORT);
	host->scsi.phase = PHASE_ABORTED;
    }
    acornscsi_sbic_issuecmd (host, CMND_NEGATEACK);
    return !ok;
}

/*
 * Function: int acornscsi_reconect_finish (AS_Host *host)
 * Purpose : finish reconnecting a command
 * Params  : host - host to complete
 * Returns : 0 if failed
 */
static
int acornscsi_reconnect_finish (AS_Host *host)
{
    if (host->scsi.disconnectable && host->SCpnt) {
	host->scsi.disconnectable = 0;
	if (host->SCpnt->target == host->scsi.reconnected.target &&
	    host->SCpnt->lun	== host->scsi.reconnected.lun &&