device_fsm.c

来自「linux 内核源代码」· C语言 代码 · 共 1,244 行 · 第 1/3 页

/*
 * Got an interrupt for a basic sense.
 */
static void
ccw_device_w4sense(struct ccw_device *cdev, enum dev_event dev_event)
{
	struct irb *irb;

	irb = (struct irb *) __LC_IRB;
	/* Check for unsolicited interrupt. */
	if (irb->scsw.stctl ==
	    		(SCSW_STCTL_STATUS_PEND | SCSW_STCTL_ALERT_STATUS)) {
		if (irb->scsw.cc == 1)
			/* Basic sense hasn't started. Try again. */
			ccw_device_do_sense(cdev, irb);
		else {
			CIO_MSG_EVENT(2, "Huh? 0.%x.%04x: unsolicited "
				      "interrupt during w4sense...\n",
				      cdev->private->dev_id.ssid,
				      cdev->private->dev_id.devno);
			if (cdev->handler)
				cdev->handler (cdev, 0, irb);
		}
		return;
	}
	/*
	 * Check if a halt or clear has been issued in the meanwhile. If yes,
	 * only deliver the halt/clear interrupt to the device driver as if it
	 * had killed the original request.
	 */
	if (irb->scsw.fctl & (SCSW_FCTL_CLEAR_FUNC | SCSW_FCTL_HALT_FUNC)) {
		/* Retry Basic Sense if requested. */
		if (cdev->private->flags.intretry) {
			cdev->private->flags.intretry = 0;
			ccw_device_do_sense(cdev, irb);
			return;
		}
		cdev->private->flags.dosense = 0;
		memset(&cdev->private->irb, 0, sizeof(struct irb));
		ccw_device_accumulate_irb(cdev, irb);
		goto call_handler;
	}
	/* Add basic sense info to irb. */
	ccw_device_accumulate_basic_sense(cdev, irb);
	if (cdev->private->flags.dosense) {
		/* Another basic sense is needed. */
		ccw_device_do_sense(cdev, irb);
		return;
	}
call_handler:
	cdev->private->state = DEV_STATE_ONLINE;
	/* Call the handler. */
	if (ccw_device_call_handler(cdev) && cdev->private->flags.doverify)
		/* Start delayed path verification. */
		ccw_device_online_verify(cdev, 0);
}

static void
ccw_device_clear_verify(struct ccw_device *cdev, enum dev_event dev_event)
{
	struct irb *irb;

	irb = (struct irb *) __LC_IRB;
	/* Accumulate status. We don't do basic sense. */
	ccw_device_accumulate_irb(cdev, irb);
	/* Remember to clear irb to avoid residuals. */
	memset(&cdev->private->irb, 0, sizeof(struct irb));
	/* Try to start delayed device verification. */
	ccw_device_online_verify(cdev, 0);
	/* Note: Don't call handler for cio initiated clear! */
}

static void
ccw_device_killing_irq(struct ccw_device *cdev, enum dev_event dev_event)
{
	struct subchannel *sch;

	sch = to_subchannel(cdev->dev.parent);
	ccw_device_set_timeout(cdev, 0);
	/* Start delayed path verification. */
	ccw_device_online_verify(cdev, 0);
	/* OK, i/o is dead now. Call interrupt handler. */
	if (cdev->handler)
		cdev->handler(cdev, cdev->private->intparm,
			      ERR_PTR(-EIO));
}

static void
ccw_device_killing_timeout(struct ccw_device *cdev, enum dev_event dev_event)
{
	int ret;

	ret = ccw_device_cancel_halt_clear(cdev);
	if (ret == -EBUSY) {
		ccw_device_set_timeout(cdev, 3*HZ);
		return;
	}
	/* Start delayed path verification. */
	ccw_device_online_verify(cdev, 0);
	if (cdev->handler)
		cdev->handler(cdev, cdev->private->intparm,
			      ERR_PTR(-EIO));
}

void device_kill_io(struct subchannel *sch)
{
	int ret;
	struct ccw_device *cdev;

	cdev = sch->dev.driver_data;
	ret = ccw_device_cancel_halt_clear(cdev);
	if (ret == -EBUSY) {
		ccw_device_set_timeout(cdev, 3*HZ);
		cdev->private->state = DEV_STATE_TIMEOUT_KILL;
		return;
	}
	/* Start delayed path verification. */
	ccw_device_online_verify(cdev, 0);
	if (cdev->handler)
		cdev->handler(cdev, cdev->private->intparm,
			      ERR_PTR(-EIO));
}

static void
ccw_device_delay_verify(struct ccw_device *cdev, enum dev_event dev_event)
{
	/* Start verification after current task finished. */
	cdev->private->flags.doverify = 1;
}

static void
ccw_device_stlck_done(struct ccw_device *cdev, enum dev_event dev_event)
{
	struct irb *irb;

	switch (dev_event) {
	case DEV_EVENT_INTERRUPT:
		irb = (struct irb *) __LC_IRB;
		/* Check for unsolicited interrupt. */
		if ((irb->scsw.stctl ==
		     (SCSW_STCTL_STATUS_PEND | SCSW_STCTL_ALERT_STATUS)) &&
		    (!irb->scsw.cc))
			/* FIXME: we should restart stlck here, but this
			 * is extremely unlikely ... */
			goto out_wakeup;

		ccw_device_accumulate_irb(cdev, irb);
		/* We don't care about basic sense etc. */
		break;
	default: /* timeout */
		break;
	}
out_wakeup:
	wake_up(&cdev->private->wait_q);
}

static void
ccw_device_start_id(struct ccw_device *cdev, enum dev_event dev_event)
{
	struct subchannel *sch;

	sch = to_subchannel(cdev->dev.parent);
	if (cio_enable_subchannel(sch, sch->schib.pmcw.isc) != 0)
		/* Couldn't enable the subchannel for i/o. Sick device. */
		return;

	/* After 60s the device recognition is considered to have failed. */
	ccw_device_set_timeout(cdev, 60*HZ);

	cdev->private->state = DEV_STATE_DISCONNECTED_SENSE_ID;
	ccw_device_sense_id_start(cdev);
}

void
device_trigger_reprobe(struct subchannel *sch)
{
	struct ccw_device *cdev;

	if (!sch->dev.driver_data)
		return;
	cdev = sch->dev.driver_data;
	if (cdev->private->state != DEV_STATE_DISCONNECTED)
		return;

	/* Update some values. */
	if (stsch(sch->schid, &sch->schib))
		return;
	if (!sch->schib.pmcw.dnv)
		return;
	/*
	 * The pim, pam, pom values may not be accurate, but they are the best
	 * we have before performing device selection :/
	 */
	sch->lpm = sch->schib.pmcw.pam & sch->opm;
	/* Re-set some bits in the pmcw that were lost. */
	sch->schib.pmcw.isc = 3;
	sch->schib.pmcw.csense = 1;
	sch->schib.pmcw.ena = 0;
	if ((sch->lpm & (sch->lpm - 1)) != 0)
		sch->schib.pmcw.mp = 1;
	sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
	/* We should also udate ssd info, but this has to wait. */
	/* Check if this is another device which appeared on the same sch. */
	if (sch->schib.pmcw.dev != cdev->private->dev_id.devno) {
		PREPARE_WORK(&cdev->private->kick_work,
			     ccw_device_move_to_orphanage);
		queue_work(slow_path_wq, &cdev->private->kick_work);
	} else
		ccw_device_start_id(cdev, 0);
}

static void
ccw_device_offline_irq(struct ccw_device *cdev, enum dev_event dev_event)
{
	struct subchannel *sch;

	sch = to_subchannel(cdev->dev.parent);
	/*
	 * An interrupt in state offline means a previous disable was not
	 * successful. Try again.
	 */
	cio_disable_subchannel(sch);
}

static void
ccw_device_change_cmfstate(struct ccw_device *cdev, enum dev_event dev_event)
{
	retry_set_schib(cdev);
	cdev->private->state = DEV_STATE_ONLINE;
	dev_fsm_event(cdev, dev_event);
}

static void ccw_device_update_cmfblock(struct ccw_device *cdev,
				       enum dev_event dev_event)
{
	cmf_retry_copy_block(cdev);
	cdev->private->state = DEV_STATE_ONLINE;
	dev_fsm_event(cdev, dev_event);
}

static void
ccw_device_quiesce_done(struct ccw_device *cdev, enum dev_event dev_event)
{
	ccw_device_set_timeout(cdev, 0);
	if (dev_event == DEV_EVENT_NOTOPER)
		cdev->private->state = DEV_STATE_NOT_OPER;
	else
		cdev->private->state = DEV_STATE_OFFLINE;
	wake_up(&cdev->private->wait_q);
}

static void
ccw_device_quiesce_timeout(struct ccw_device *cdev, enum dev_event dev_event)
{
	int ret;

	ret = ccw_device_cancel_halt_clear(cdev);
	switch (ret) {
	case 0:
		cdev->private->state = DEV_STATE_OFFLINE;
		wake_up(&cdev->private->wait_q);
		break;
	case -ENODEV:
		cdev->private->state = DEV_STATE_NOT_OPER;
		wake_up(&cdev->private->wait_q);
		break;
	default:
		ccw_device_set_timeout(cdev, HZ/10);
	}
}

/*
 * No operation action. This is used e.g. to ignore a timeout event in
 * state offline.
 */
static void
ccw_device_nop(struct ccw_device *cdev, enum dev_event dev_event)
{
}

/*
 * Bug operation action. 
 */
static void
ccw_device_bug(struct ccw_device *cdev, enum dev_event dev_event)
{
	CIO_MSG_EVENT(0, "dev_jumptable[%i][%i] == NULL\n",
		      cdev->private->state, dev_event);
	BUG();
}

/*
 * device statemachine
 */
fsm_func_t *dev_jumptable[NR_DEV_STATES][NR_DEV_EVENTS] = {
	[DEV_STATE_NOT_OPER] = {
		[DEV_EVENT_NOTOPER]	= ccw_device_nop,
		[DEV_EVENT_INTERRUPT]	= ccw_device_bug,
		[DEV_EVENT_TIMEOUT]	= ccw_device_nop,
		[DEV_EVENT_VERIFY]	= ccw_device_nop,
	},
	[DEV_STATE_SENSE_PGID] = {
		[DEV_EVENT_NOTOPER]	= ccw_device_generic_notoper,
		[DEV_EVENT_INTERRUPT]	= ccw_device_sense_pgid_irq,
		[DEV_EVENT_TIMEOUT]	= ccw_device_onoff_timeout,
		[DEV_EVENT_VERIFY]	= ccw_device_nop,
	},
	[DEV_STATE_SENSE_ID] = {
		[DEV_EVENT_NOTOPER]	= ccw_device_recog_notoper,
		[DEV_EVENT_INTERRUPT]	= ccw_device_sense_id_irq,
		[DEV_EVENT_TIMEOUT]	= ccw_device_recog_timeout,
		[DEV_EVENT_VERIFY]	= ccw_device_nop,
	},
	[DEV_STATE_OFFLINE] = {
		[DEV_EVENT_NOTOPER]	= ccw_device_generic_notoper,
		[DEV_EVENT_INTERRUPT]	= ccw_device_offline_irq,
		[DEV_EVENT_TIMEOUT]	= ccw_device_nop,
		[DEV_EVENT_VERIFY]	= ccw_device_nop,
	},
	[DEV_STATE_VERIFY] = {
		[DEV_EVENT_NOTOPER]	= ccw_device_generic_notoper,
		[DEV_EVENT_INTERRUPT]	= ccw_device_verify_irq,
		[DEV_EVENT_TIMEOUT]	= ccw_device_onoff_timeout,
		[DEV_EVENT_VERIFY]	= ccw_device_delay_verify,
	},
	[DEV_STATE_ONLINE] = {
		[DEV_EVENT_NOTOPER]	= ccw_device_generic_notoper,
		[DEV_EVENT_INTERRUPT]	= ccw_device_irq,
		[DEV_EVENT_TIMEOUT]	= ccw_device_online_timeout,
		[DEV_EVENT_VERIFY]	= ccw_device_online_verify,
	},
	[DEV_STATE_W4SENSE] = {
		[DEV_EVENT_NOTOPER]	= ccw_device_generic_notoper,
		[DEV_EVENT_INTERRUPT]	= ccw_device_w4sense,
		[DEV_EVENT_TIMEOUT]	= ccw_device_nop,
		[DEV_EVENT_VERIFY]	= ccw_device_online_verify,
	},
	[DEV_STATE_DISBAND_PGID] = {
		[DEV_EVENT_NOTOPER]	= ccw_device_generic_notoper,
		[DEV_EVENT_INTERRUPT]	= ccw_device_disband_irq,
		[DEV_EVENT_TIMEOUT]	= ccw_device_onoff_timeout,
		[DEV_EVENT_VERIFY]	= ccw_device_nop,
	},
	[DEV_STATE_BOXED] = {
		[DEV_EVENT_NOTOPER]	= ccw_device_generic_notoper,
		[DEV_EVENT_INTERRUPT]	= ccw_device_stlck_done,
		[DEV_EVENT_TIMEOUT]	= ccw_device_stlck_done,
		[DEV_EVENT_VERIFY]	= ccw_device_nop,
	},
	/* states to wait for i/o completion before doing something */
	[DEV_STATE_CLEAR_VERIFY] = {
		[DEV_EVENT_NOTOPER]	= ccw_device_generic_notoper,
		[DEV_EVENT_INTERRUPT]   = ccw_device_clear_verify,
		[DEV_EVENT_TIMEOUT]	= ccw_device_nop,
		[DEV_EVENT_VERIFY]	= ccw_device_nop,
	},
	[DEV_STATE_TIMEOUT_KILL] = {
		[DEV_EVENT_NOTOPER]	= ccw_device_generic_notoper,
		[DEV_EVENT_INTERRUPT]	= ccw_device_killing_irq,
		[DEV_EVENT_TIMEOUT]	= ccw_device_killing_timeout,
		[DEV_EVENT_VERIFY]	= ccw_device_nop, //FIXME
	},
	[DEV_STATE_QUIESCE] = {
		[DEV_EVENT_NOTOPER]	= ccw_device_quiesce_done,
		[DEV_EVENT_INTERRUPT]	= ccw_device_quiesce_done,
		[DEV_EVENT_TIMEOUT]	= ccw_device_quiesce_timeout,
		[DEV_EVENT_VERIFY]	= ccw_device_nop,
	},
	/* special states for devices gone not operational */
	[DEV_STATE_DISCONNECTED] = {
		[DEV_EVENT_NOTOPER]	= ccw_device_nop,
		[DEV_EVENT_INTERRUPT]	= ccw_device_start_id,
		[DEV_EVENT_TIMEOUT]	= ccw_device_bug,
		[DEV_EVENT_VERIFY]	= ccw_device_start_id,
	},
	[DEV_STATE_DISCONNECTED_SENSE_ID] = {
		[DEV_EVENT_NOTOPER]	= ccw_device_recog_notoper,
		[DEV_EVENT_INTERRUPT]	= ccw_device_sense_id_irq,
		[DEV_EVENT_TIMEOUT]	= ccw_device_recog_timeout,
		[DEV_EVENT_VERIFY]	= ccw_device_nop,
	},
	[DEV_STATE_CMFCHANGE] = {
		[DEV_EVENT_NOTOPER]	= ccw_device_change_cmfstate,
		[DEV_EVENT_INTERRUPT]	= ccw_device_change_cmfstate,
		[DEV_EVENT_TIMEOUT]	= ccw_device_change_cmfstate,
		[DEV_EVENT_VERIFY]	= ccw_device_change_cmfstate,
	},
	[DEV_STATE_CMFUPDATE] = {
		[DEV_EVENT_NOTOPER]	= ccw_device_update_cmfblock,
		[DEV_EVENT_INTERRUPT]	= ccw_device_update_cmfblock,
		[DEV_EVENT_TIMEOUT]	= ccw_device_update_cmfblock,
		[DEV_EVENT_VERIFY]	= ccw_device_update_cmfblock,
	},
};

/*
 * io_subchannel_irq is called for "real" interrupts or for status
 * pending conditions on msch.
 */
void
io_subchannel_irq (struct device *pdev)
{
	struct ccw_device *cdev;

	cdev = to_subchannel(pdev)->dev.driver_data;

	CIO_TRACE_EVENT (3, "IRQ");
	CIO_TRACE_EVENT (3, pdev->bus_id);
	if (cdev)
		dev_fsm_event(cdev, DEV_EVENT_INTERRUPT);
}

EXPORT_SYMBOL_GPL(ccw_device_set_timeout);