ncr5380.c

GNU Mach 微内核源代码, 基于美国卡内基美隆大学的 Mach 研究项目

#ifdef PAS16_PUBLIC_RELEASE
        pas_wmaxi = pas_maxi = 0;
#endif
      return(-ENOSYS);  /* Currently this is a no-op */
   }
   SPRINTF("NCR5380 core release=%d.   ", NCR5380_PUBLIC_RELEASE);
   if (((struct NCR5380_hostdata *)instance->hostdata)->flags & FLAG_NCR53C400)
        SPRINTF("ncr53c400 release=%d.  ", NCR53C400_PUBLIC_RELEASE);
#ifdef DTC_PUBLIC_RELEASE
   SPRINTF("DTC 3180/3280 release %d", DTC_PUBLIC_RELEASE);
#endif
#ifdef T128_PUBLIC_RELEASE
   SPRINTF("T128 release %d", T128_PUBLIC_RELEASE);
#endif
#ifdef GENERIC_NCR5380_PUBLIC_RELEASE
   SPRINTF("Generic5380 release %d", GENERIC_NCR5380_PUBLIC_RELEASE);
#endif
#ifdef PAS16_PUBLIC_RELEASE
SPRINTF("PAS16 release=%d", PAS16_PUBLIC_RELEASE);
#endif

   SPRINTF("\nBase Addr: 0x%05lX    ", (long)instance->base);
   SPRINTF("io_port: %04x      ", (int)instance->io_port);
   if (instance->irq == IRQ_NONE)
      SPRINTF("IRQ: None.\n");
   else
      SPRINTF("IRQ: %d.\n", instance->irq);

#ifdef DTC_PUBLIC_RELEASE
   SPRINTF("Highwater I/O busy_spin_counts -- write: %d  read: %d\n",
        dtc_wmaxi, dtc_maxi);
#endif
#ifdef PAS16_PUBLIC_RELEASE
   SPRINTF("Highwater I/O busy_spin_counts -- write: %d  read: %d\n",
        pas_wmaxi, pas_maxi);
#endif
    cli();
    SPRINTF("NCR5380 : coroutine is%s running.\n", main_running ? "" : "n't");
    if (!hostdata->connected)
      SPRINTF("scsi%d: no currently connected command\n", instance->host_no);
   else
      pos = lprint_Scsi_Cmnd ((Scsi_Cmnd *) hostdata->connected,
        pos, buffer, length);
   SPRINTF("scsi%d: issue_queue\n", instance->host_no);
   for (ptr = (Scsi_Cmnd *) hostdata->issue_queue; ptr;
        ptr = (Scsi_Cmnd *) ptr->host_scribble)
        pos = lprint_Scsi_Cmnd (ptr, pos, buffer, length);

   SPRINTF("scsi%d: disconnected_queue\n", instance->host_no);
   for (ptr = (Scsi_Cmnd *) hostdata->disconnected_queue; ptr;
        ptr = (Scsi_Cmnd *) ptr->host_scribble)
        pos = lprint_Scsi_Cmnd (ptr, pos, buffer, length);

   sti();
   *start=buffer;
  if (pos - buffer < offset)
    return 0;
  else if (pos - buffer - offset < length)
    return pos - buffer - offset;
  return length;
}

static 
char *lprint_Scsi_Cmnd (Scsi_Cmnd *cmd, char *pos, char *buffer, int length) {
   SPRINTF("scsi%d : destination target %d, lun %d\n",
        cmd->host->host_no, cmd->target, cmd->lun);
   SPRINTF("        command = ");
   pos = lprint_command (cmd->cmnd, pos, buffer, length);
   return (pos);
}

static 
char *lprint_command (unsigned char *command,
     char *pos, char *buffer, int length) {
   int i, s;
   pos = lprint_opcode(command[0], pos, buffer, length);
   for ( i = 1, s = COMMAND_SIZE(command[0]); i < s; ++i)
      SPRINTF("%02x ", command[i]);
   SPRINTF("\n");
   return(pos);
}

static 
char *lprint_opcode(int opcode, char *pos, char *buffer, int length) {
   SPRINTF("%2d (0x%02x)", opcode, opcode);
   return(pos);
}


/* 
 * Function : void NCR5380_init (struct Scsi_Host *instance, flags)
 *
 * Purpose : initializes *instance and corresponding 5380 chip,
 *	with flags OR'd into the initial flags value.
 *
 * Inputs : instance - instantiation of the 5380 driver.  
 *
 * Notes : I assume that the host, hostno, and id bits have been
 * 	set correctly.  I don't care about the irq and other fields. 
 * 
 */

static void NCR5380_init (struct Scsi_Host *instance, int flags) {
    NCR5380_local_declare();
    int i, pass;
    unsigned long timeout;
    struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *) 
	instance->hostdata;

    /* 
     * On NCR53C400 boards, NCR5380 registers are mapped 8 past 
     * the base address.
     */

#ifdef NCR53C400
    if (flags & FLAG_NCR53C400)
	instance->NCR5380_instance_name += NCR53C400_address_adjust;
#endif

    NCR5380_setup(instance);

    NCR5380_all_init();

    hostdata->aborted = 0;
    hostdata->id_mask = 1 << instance->this_id;
    for (i = hostdata->id_mask; i <= 0x80; i <<= 1)
	if (i > hostdata->id_mask)
	    hostdata->id_higher_mask |= i;
    for (i = 0; i < 8; ++i)
	hostdata->busy[i] = 0;
#ifdef REAL_DMA
    hostdata->dmalen = 0;
#endif
    hostdata->targets_present = 0;
    hostdata->connected = NULL;
    hostdata->issue_queue = NULL;
    hostdata->disconnected_queue = NULL;
#ifdef NCR5380_STATS
    for (i = 0; i < 8; ++i) {
	hostdata->time_read[i] = 0;
	hostdata->time_write[i] = 0;
	hostdata->bytes_read[i] = 0;
	hostdata->bytes_write[i] = 0;
    }
    hostdata->timebase = 0;
    hostdata->pendingw = 0;
    hostdata->pendingr = 0;
#endif

    /* The CHECK code seems to break the 53C400. Will check it later maybe */
    if (flags & FLAG_NCR53C400)
	hostdata->flags = FLAG_HAS_LAST_BYTE_SENT | flags;
    else
	hostdata->flags = FLAG_CHECK_LAST_BYTE_SENT | flags;

    if (!the_template) {
	the_template = instance->hostt;
	first_instance = instance;
    }
	

#ifdef USLEEP
    hostdata->time_expires = 0;
    hostdata->next_timer = NULL;
#endif

#ifndef AUTOSENSE
    if ((instance->cmd_per_lun > 1) || instance->can_queue > 1)) 
	 printk("scsi%d : WARNING : support for multiple outstanding commands enabled\n"
		"         without AUTOSENSE option, contingent allegiance conditions may\n"
		"         be incorrectly cleared.\n", instance->host_no);
#endif /* def AUTOSENSE */

    NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
    NCR5380_write(MODE_REG, MR_BASE);
    NCR5380_write(TARGET_COMMAND_REG, 0);
    NCR5380_write(SELECT_ENABLE_REG, 0);

#ifdef NCR53C400
    if (hostdata->flags & FLAG_NCR53C400) {
	NCR5380_write(C400_CONTROL_STATUS_REG, CSR_BASE);
    }
#endif

    /* 
     * Detect and correct bus wedge problems.
     *
     * If the system crashed, it may have crashed in a state 
     * where a SCSI command was still executing, and the 
     * SCSI bus is not in a BUS FREE STATE.
     *
     * If this is the case, we'll try to abort the currently
     * established nexus which we know nothing about, and that
     * failing, do a hard reset of the SCSI bus 
     */

    for (pass = 1; (NCR5380_read(STATUS_REG) & SR_BSY) &&
	  pass <= 6 ; ++pass) {
	switch (pass) {
	case 1:
	case 3:
	case 5:
	    printk("scsi%d: SCSI bus busy, waiting up to five seconds\n",
		instance->host_no);
	    timeout = jiffies + 5*HZ;
	    while (jiffies < timeout && (NCR5380_read(STATUS_REG) & SR_BSY));
	    break;
	case 2:
	    printk("scsi%d: bus busy, attempting abort\n",
		instance->host_no);
	    do_abort (instance);
	    break;
	case 4:
	    printk("scsi%d: bus busy, attempting reset\n",
		instance->host_no);
	    do_reset (instance);
	    break;
	case 6:
	    printk("scsi%d: bus locked solid or invalid override\n",
		instance->host_no);
	}
    }
}

/* 
 * Function : int NCR5380_queue_command (Scsi_Cmnd *cmd, 
 *	void (*done)(Scsi_Cmnd *)) 
 *
 * Purpose :  enqueues a SCSI command
 *
 * Inputs : cmd - SCSI command, done - function called on completion, with
 *	a pointer to the command descriptor.
 * 
 * Returns : 0
 *
 * Side effects : 
 *      cmd is added to the per instance issue_queue, with minor 
 *	twiddling done to the host specific fields of cmd.  If the 
 *	main coroutine is not running, it is restarted.
 *
 */

/* Only make static if a wrapper function is used */
#ifndef NCR5380_queue_command
static
#endif
int NCR5380_queue_command (Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *)) {
    struct Scsi_Host *instance = cmd->host;
    struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *)
	instance->hostdata;
    Scsi_Cmnd *tmp;

#if (NDEBUG & NDEBUG_NO_WRITE)
    switch (cmd->cmnd[0]) {
    case WRITE_6:
    case WRITE_10:
	printk("scsi%d : WRITE attempted with NO_WRITE debugging flag set\n",
	    instance->host_no);
	cmd->result = (DID_ERROR << 16);
	done(cmd);
	return 0;
    }
#endif /* (NDEBUG & NDEBUG_NO_WRITE) */

#ifdef NCR5380_STATS
# if 0
    if (!hostdata->connected && !hostdata->issue_queue &&
	!hostdata->disconnected_queue) {
	hostdata->timebase = jiffies;
    }
# endif
# ifdef NCR5380_STAT_LIMIT
    if (cmd->request_bufflen > NCR5380_STAT_LIMIT)
# endif
	switch (cmd->cmnd[0])
	{
	    case WRITE:
	    case WRITE_6:
	    case WRITE_10:
		hostdata->time_write[cmd->target] -= (jiffies - hostdata->timebase);
		hostdata->bytes_write[cmd->target] += cmd->request_bufflen;
		hostdata->pendingw++;
		break;
	    case READ:
	    case READ_6:
	    case READ_10:
		hostdata->time_read[cmd->target] -= (jiffies - hostdata->timebase);
		hostdata->bytes_read[cmd->target] += cmd->request_bufflen;
		hostdata->pendingr++;
		break;
	}
#endif

    /* 
     * We use the host_scribble field as a pointer to the next command  
     * in a queue 
     */

    cmd->host_scribble = NULL;
    cmd->scsi_done = done;

    cmd->result = 0;


    /* 
     * Insert the cmd into the issue queue. Note that REQUEST SENSE 
     * commands are added to the head of the queue since any command will
     * clear the contingent allegiance condition that exists and the 
     * sense data is only guaranteed to be valid while the condition exists.
     */

    cli();
    if (!(hostdata->issue_queue) || (cmd->cmnd[0] == REQUEST_SENSE)) {
	LIST(cmd, hostdata->issue_queue);
	cmd->host_scribble = (unsigned char *) hostdata->issue_queue;
	hostdata->issue_queue = cmd;
    } else {
	for (tmp = (Scsi_Cmnd *) hostdata->issue_queue; tmp->host_scribble; 
		tmp = (Scsi_Cmnd *) tmp->host_scribble);
	LIST(cmd, tmp);
	tmp->host_scribble = (unsigned char *) cmd;
    }
#if (NDEBUG & NDEBUG_QUEUES)
    printk("scsi%d : command added to %s of queue\n", instance->host_no,
	(cmd->cmnd[0] == REQUEST_SENSE) ? "head" : "tail");
#endif

/* Run the coroutine if it isn't already running. */
    run_main();
    return 0;
}

/*
 * Function : NCR5380_main (void) 
 *
 * Purpose : NCR5380_main is a coroutine that runs as long as more work can 
 *	be done on the NCR5380 host adapters in a system.  Both 
 *	NCR5380_queue_command() and NCR5380_intr() will try to start it 
 *	in case it is not running.
 * 
 * NOTE : NCR5380_main exits with interrupts *disabled*, the caller should 
 *  reenable them.  This prevents reentrancy and kernel stack overflow.
 */ 	
    
static void NCR5380_main (void) {
    Scsi_Cmnd *tmp, *prev;
    struct Scsi_Host *instance;
    struct NCR5380_hostdata *hostdata;
    int done;

    /*
     * We run (with interrupts disabled) until we're sure that none of 
     * the host adapters have anything that can be done, at which point 
     * we set main_running to 0 and exit.
     *
     * Interrupts are enabled before doing various other internal 
     * instructions, after we've decided that we need to run through
     * the loop again.
     *
     * this should prevent any race conditions.
     */

    do {
	cli(); /* Freeze request queues */
	done = 1;
	for (instance = first_instance; instance && 
	    instance->hostt == the_template; instance=instance->next) {
	    hostdata = (struct NCR5380_hostdata *) instance->hostdata;
	    cli();
	    if (!hostdata->connected) {
#if (NDEBUG & NDEBUG_MAIN)
		printk("scsi%d : not connected\n", instance->host_no);
#endif
		/*
		 * Search through the issue_queue for a command destined
		 * for a target that's not busy.
		 */
#if (NDEBUG & NDEBUG_LISTS)
		for (tmp= (Scsi_Cmnd *) hostdata->issue_queue, prev=NULL; tmp && (tmp != prev); prev=tmp, tmp=(Scsi_Cmnd*)tmp->host_scribble)
		    ;
		    /*printk("%p  ", tmp);*/
		if ((tmp == prev) && tmp) printk(" LOOP\n");/* else printk("\n");*/
#endif
		for (tmp = (Scsi_Cmnd *) hostdata->issue_queue, 
		    prev = NULL; tmp; prev = tmp, tmp = (Scsi_Cmnd *) 
		    tmp->host_scribble) {

#if (NDEBUG & NDEBUG_LISTS)
		    if (prev != tmp)
			printk("MAIN tmp=%p   target=%d   busy=%d lun=%d\n", tmp, tmp->target, hostdata->busy[tmp->target], tmp->lun);
#endif
		    /*  When we find one, remove it from the issue queue. */
		    if (!(hostdata->busy[tmp->target] & (1 << tmp->lun))) {
			if (prev) {
			    REMOVE(prev,prev->host_scribble,tmp,tmp->host_scribble);
			    prev->host_scribble = tmp->host_scribble;
			} else {
			    REMOVE(-1,hostdata->issue_queue,tmp,tmp->host_scribble);
			    hostdata->issue_queue = (Scsi_Cmnd *) tmp->host_scribble;
			}
			tmp->host_scribble = NULL;

			/* reenable interrupts after finding one */
			sti();

			/* 
			 * Attempt to establish an I_T_L nexus here. 
			 * On success, instance->hostdata->connected is set.
			 * On failure, we must add the command back to the
			 *   issue queue so we can keep trying.	
			 */
#if (NDEBUG & (NDEBUG_MAIN | NDEBUG_QUEUES))
			printk("scsi%d : main() : command for target %d lun %d removed from issue_queue\n",
			    instance->host_no, tmp->target, tmp->lun);
#endif
    		
			/*
			 * A successful selection is defined as one that 
			 * leaves us with the command connected and 
			 * in hostdata->connected, OR has terminated the
			 * command.