ipmi_bt_sm.c

linux-2.6.15.6

	if (bt_debug & BT_DEBUG_MSG) {
    		printk(KERN_WARNING "BT: write %d bytes seq=0x%02X",
			bt->write_count, bt->seq);
		for (i = 0; i < bt->write_count; i++)
			printk (" %02x", bt->write_data[i]);
		printk ("\n");
	}
	for (i = 0; i < bt->write_count; i++)
	       HOST2BMC(bt->write_data[i]);
}

static inline int read_all_bytes(struct si_sm_data *bt)
{
	unsigned char i;

	bt->read_data[0] = BMC2HOST;
	bt->read_count = bt->read_data[0];
	if (bt_debug & BT_DEBUG_MSG)
    		printk(KERN_WARNING "BT: read %d bytes:", bt->read_count);

	/* minimum: length, NetFn, Seq, Cmd, cCode == 5 total, or 4 more
	   following the length byte. */
	if (bt->read_count < 4 || bt->read_count >= IPMI_MAX_MSG_LENGTH) {
		if (bt_debug & BT_DEBUG_MSG)
			printk("bad length %d\n", bt->read_count);
		bt->truncated = 1;
		return 1;	/* let next XACTION START clean it up */
	}
	for (i = 1; i <= bt->read_count; i++)
	       bt->read_data[i] = BMC2HOST;
	bt->read_count++;	/* account for the length byte */

	if (bt_debug & BT_DEBUG_MSG) {
	    	for (i = 0; i < bt->read_count; i++)
			printk (" %02x", bt->read_data[i]);
	    	printk ("\n");
	}
	if (bt->seq != bt->write_data[2])	/* idiot check */
		printk(KERN_DEBUG "BT: internal error: sequence mismatch\n");

	/* per the spec, the (NetFn, Seq, Cmd) tuples should match */
	if ((bt->read_data[3] == bt->write_data[3]) &&		/* Cmd */
        	(bt->read_data[2] == bt->write_data[2]) &&	/* Sequence */
        	((bt->read_data[1] & 0xF8) == (bt->write_data[1] & 0xF8)))
			return 1;

	if (bt_debug & BT_DEBUG_MSG)
	       printk(KERN_WARNING "BT: bad packet: "
		"want 0x(%02X, %02X, %02X) got (%02X, %02X, %02X)\n",
		bt->write_data[1], bt->write_data[2], bt->write_data[3],
		bt->read_data[1],  bt->read_data[2],  bt->read_data[3]);
	return 0;
}

/* Modifies bt->state appropriately, need to get into the bt_event() switch */

static void error_recovery(struct si_sm_data *bt, char *reason)
{
	unsigned char status;
	char buf[40]; /* For getting status */

	bt->timeout = BT_NORMAL_TIMEOUT; /* various places want to retry */

	status = BT_STATUS;
	printk(KERN_DEBUG "BT: %s in %s %s\n", reason, STATE2TXT,
	       STATUS2TXT(buf));

	(bt->error_retries)++;
	if (bt->error_retries > BT_RETRY_LIMIT) {
		printk(KERN_DEBUG "retry limit (%d) exceeded\n", BT_RETRY_LIMIT);
		bt->state = BT_STATE_HOSED;
		if (!bt->nonzero_status)
			printk(KERN_ERR "IPMI: BT stuck, try power cycle\n");
		else if (bt->error_retries <= BT_RETRY_LIMIT + 1) {
			printk(KERN_DEBUG "IPMI: BT reset (takes 5 secs)\n");
        		bt->state = BT_STATE_RESET1;
		}
	return;
	}

	/* Sometimes the BMC queues get in an "off-by-one" state...*/
	if ((bt->state == BT_STATE_B2H_WAIT) && (status & BT_B2H_ATN)) {
    		printk(KERN_DEBUG "retry B2H_WAIT\n");
		return;
	}

	printk(KERN_DEBUG "restart command\n");
	bt->state = BT_STATE_RESTART;
}

/* Check the status and (possibly) advance the BT state machine.  The
   default return is SI_SM_CALL_WITH_DELAY. */

static enum si_sm_result bt_event(struct si_sm_data *bt, long time)
{
	unsigned char status;
	char buf[40]; /* For getting status */
	int i;

	status = BT_STATUS;
	bt->nonzero_status |= status;

	if ((bt_debug & BT_DEBUG_STATES) && (bt->state != bt->last_state))
		printk(KERN_WARNING "BT: %s %s TO=%ld - %ld \n",
			STATE2TXT,
			STATUS2TXT(buf),
			bt->timeout,
			time);
	bt->last_state = bt->state;

	if (bt->state == BT_STATE_HOSED)
	       return SI_SM_HOSED;

	if (bt->state != BT_STATE_IDLE) {	/* do timeout test */
		bt->timeout -= time;
		if ((bt->timeout < 0) && (bt->state < BT_STATE_RESET1)) {
			error_recovery(bt, "timed out");
			return SI_SM_CALL_WITHOUT_DELAY;
		}
	}

	switch (bt->state) {

    	case BT_STATE_IDLE:	/* check for asynchronous messages */
		if (status & BT_SMS_ATN) {
			BT_CONTROL(BT_SMS_ATN);	/* clear it */
			return SI_SM_ATTN;
		}
		return SI_SM_IDLE;

	case BT_STATE_XACTION_START:
		if (status & BT_H_BUSY) {
			BT_CONTROL(BT_H_BUSY);
			break;
		}
    		if (status & BT_B2H_ATN)
		       break;
		bt->state = BT_STATE_WRITE_BYTES;
		return SI_SM_CALL_WITHOUT_DELAY;	/* for logging */

	case BT_STATE_WRITE_BYTES:
		if (status & (BT_B_BUSY | BT_H2B_ATN))
		       break;
		BT_CONTROL(BT_CLR_WR_PTR);
		write_all_bytes(bt);
		BT_CONTROL(BT_H2B_ATN);	/* clears too fast to catch? */
		bt->state = BT_STATE_WRITE_CONSUME;
		return SI_SM_CALL_WITHOUT_DELAY; /* it MIGHT sail through */

	case BT_STATE_WRITE_CONSUME: /* BMCs usually blow right thru here */
        	if (status & (BT_H2B_ATN | BT_B_BUSY))
		       break;
		bt->state = BT_STATE_B2H_WAIT;
		/* fall through with status */

	/* Stay in BT_STATE_B2H_WAIT until a packet matches.  However, spinning
	   hard here, constantly reading status, seems to hold off the
	   generation of B2H_ATN so ALWAYS return CALL_WITH_DELAY. */

	case BT_STATE_B2H_WAIT:
    		if (!(status & BT_B2H_ATN))
		       break;

		/* Assume ordered, uncached writes: no need to wait */
		if (!(status & BT_H_BUSY))
		       BT_CONTROL(BT_H_BUSY); /* set */
		BT_CONTROL(BT_B2H_ATN);		/* clear it, ACK to the BMC */
		BT_CONTROL(BT_CLR_RD_PTR);	/* reset the queue */
		i = read_all_bytes(bt);
		BT_CONTROL(BT_H_BUSY);		/* clear */
		if (!i)				/* Try this state again */
		       break;
		bt->state = BT_STATE_READ_END;
		return SI_SM_CALL_WITHOUT_DELAY;	/* for logging */

    	case BT_STATE_READ_END:

		/* I could wait on BT_H_BUSY to go clear for a truly clean
		   exit.  However, this is already done in XACTION_START
		   and the (possible) extra loop/status/possible wait affects
		   performance.  So, as long as it works, just ignore H_BUSY */

#ifdef MAKE_THIS_TRUE_IF_NECESSARY

		if (status & BT_H_BUSY)
		       break;
#endif
		bt->seq++;
		bt->state = BT_STATE_IDLE;
		return SI_SM_TRANSACTION_COMPLETE;

	case BT_STATE_RESET1:
    		reset_flags(bt);
    		bt->timeout = BT_RESET_DELAY;
		bt->state = BT_STATE_RESET2;
		break;

	case BT_STATE_RESET2:		/* Send a soft reset */
		BT_CONTROL(BT_CLR_WR_PTR);
		HOST2BMC(3);		/* number of bytes following */
		HOST2BMC(0x18);		/* NetFn/LUN == Application, LUN 0 */
		HOST2BMC(42);		/* Sequence number */
		HOST2BMC(3);		/* Cmd == Soft reset */
		BT_CONTROL(BT_H2B_ATN);
		bt->state = BT_STATE_RESET3;
		break;

	case BT_STATE_RESET3:
		if (bt->timeout > 0)
		       return SI_SM_CALL_WITH_DELAY;
		bt->state = BT_STATE_RESTART;	/* printk in debug modes */
		break;

	case BT_STATE_RESTART:		/* don't reset retries! */
		reset_flags(bt);
		bt->write_data[2] = ++bt->seq;
		bt->read_count = 0;
		bt->nonzero_status = 0;
		bt->timeout = BT_NORMAL_TIMEOUT;
		bt->state = BT_STATE_XACTION_START;
		break;

	default:	/* HOSED is supposed to be caught much earlier */
		error_recovery(bt, "internal logic error");
		break;
  	}
  	return SI_SM_CALL_WITH_DELAY;
}

static int bt_detect(struct si_sm_data *bt)
{
	/* It's impossible for the BT status and interrupt registers to be
	   all 1's, (assuming a properly functioning, self-initialized BMC)
	   but that's what you get from reading a bogus address, so we
	   test that first.  The calling routine uses negative logic. */

	if ((BT_STATUS == 0xFF) && (BT_INTMASK_R == 0xFF))
	       return 1;
	reset_flags(bt);
	return 0;
}

static void bt_cleanup(struct si_sm_data *bt)
{
}

static int bt_size(void)
{
	return sizeof(struct si_sm_data);
}

struct si_sm_handlers bt_smi_handlers =
{
	.init_data         = bt_init_data,
	.start_transaction = bt_start_transaction,
	.get_result        = bt_get_result,
	.event             = bt_event,
	.detect            = bt_detect,
	.cleanup           = bt_cleanup,
	.size              = bt_size,
};