static enum si_sm_result kcs_event()

in ipmi/ipmi_kcs_sm.c [330:503]

• 138 lines of code
• 33 McCabe index (conditional complexity)

static enum si_sm_result kcs_event(struct si_sm_data *kcs, long time)
{
	unsigned char status;
	unsigned char state;

	status = read_status(kcs);

	if (kcs_debug & KCS_DEBUG_STATES)
		dev_dbg(kcs->io->dev,
			"KCS: State = %d, %x\n", kcs->state, status);

	/* All states wait for ibf, so just do it here. */
	if (!check_ibf(kcs, status, time))
		return SI_SM_CALL_WITH_DELAY;

	/* Just about everything looks at the KCS state, so grab that, too. */
	state = GET_STATUS_STATE(status);

	switch (kcs->state) {
	case KCS_IDLE:
		/* If there's and interrupt source, turn it off. */
		clear_obf(kcs, status);

		if (GET_STATUS_ATN(status))
			return SI_SM_ATTN;
		else
			return SI_SM_IDLE;

	case KCS_START_OP:
		if (state != KCS_IDLE_STATE) {
			start_error_recovery(kcs,
					     "State machine not idle at start");
			break;
		}

		clear_obf(kcs, status);
		write_cmd(kcs, KCS_WRITE_START);
		kcs->state = KCS_WAIT_WRITE_START;
		break;

	case KCS_WAIT_WRITE_START:
		if (state != KCS_WRITE_STATE) {
			start_error_recovery(
				kcs,
				"Not in write state at write start");
			break;
		}
		read_data(kcs);
		if (kcs->write_count == 1) {
			write_cmd(kcs, KCS_WRITE_END);
			kcs->state = KCS_WAIT_WRITE_END;
		} else {
			write_next_byte(kcs);
			kcs->state = KCS_WAIT_WRITE;
		}
		break;

	case KCS_WAIT_WRITE:
		if (state != KCS_WRITE_STATE) {
			start_error_recovery(kcs,
					     "Not in write state for write");
			break;
		}
		clear_obf(kcs, status);
		if (kcs->write_count == 1) {
			write_cmd(kcs, KCS_WRITE_END);
			kcs->state = KCS_WAIT_WRITE_END;
		} else {
			write_next_byte(kcs);
		}
		break;

	case KCS_WAIT_WRITE_END:
		if (state != KCS_WRITE_STATE) {
			start_error_recovery(kcs,
					     "Not in write state"
					     " for write end");
			break;
		}
		clear_obf(kcs, status);
		write_next_byte(kcs);
		kcs->state = KCS_WAIT_READ;
		break;

	case KCS_WAIT_READ:
		if ((state != KCS_READ_STATE) && (state != KCS_IDLE_STATE)) {
			start_error_recovery(
				kcs,
				"Not in read or idle in read state");
			break;
		}

		if (state == KCS_READ_STATE) {
			if (!check_obf(kcs, status, time))
				return SI_SM_CALL_WITH_DELAY;
			read_next_byte(kcs);
		} else {
			/*
			 * We don't implement this exactly like the state
			 * machine in the spec.  Some broken hardware
			 * does not write the final dummy byte to the
			 * read register.  Thus obf will never go high
			 * here.  We just go straight to idle, and we
			 * handle clearing out obf in idle state if it
			 * happens to come in.
			 */
			clear_obf(kcs, status);
			kcs->orig_write_count = 0;
			kcs->state = KCS_IDLE;
			return SI_SM_TRANSACTION_COMPLETE;
		}
		break;

	case KCS_ERROR0:
		clear_obf(kcs, status);
		status = read_status(kcs);
		if (GET_STATUS_OBF(status))
			/* controller isn't responding */
			if (time_before(jiffies, kcs->error0_timeout))
				return SI_SM_CALL_WITH_TICK_DELAY;
		write_cmd(kcs, KCS_GET_STATUS_ABORT);
		kcs->state = KCS_ERROR1;
		break;

	case KCS_ERROR1:
		clear_obf(kcs, status);
		write_data(kcs, 0);
		kcs->state = KCS_ERROR2;
		break;

	case KCS_ERROR2:
		if (state != KCS_READ_STATE) {
			start_error_recovery(kcs,
					     "Not in read state for error2");
			break;
		}
		if (!check_obf(kcs, status, time))
			return SI_SM_CALL_WITH_DELAY;

		clear_obf(kcs, status);
		write_data(kcs, KCS_READ_BYTE);
		kcs->state = KCS_ERROR3;
		break;

	case KCS_ERROR3:
		if (state != KCS_IDLE_STATE) {
			start_error_recovery(kcs,
					     "Not in idle state for error3");
			break;
		}

		if (!check_obf(kcs, status, time))
			return SI_SM_CALL_WITH_DELAY;

		clear_obf(kcs, status);
		if (kcs->orig_write_count) {
			restart_kcs_transaction(kcs);
		} else {
			kcs->state = KCS_IDLE;
			return SI_SM_TRANSACTION_COMPLETE;
		}
		break;

	case KCS_HOSED:
		break;
	}

	if (kcs->state == KCS_HOSED) {
		init_kcs_data(kcs, kcs->io);
		return SI_SM_HOSED;
	}

	return SI_SM_CALL_WITHOUT_DELAY;
}