device_fsm.c

linux-2.6.15.6

/*
 * drivers/s390/cio/device_fsm.c
 * finite state machine for device handling
 *
 *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
 *			 IBM Corporation
 *    Author(s): Cornelia Huck([e-mail])
 *		 Martin Schwidefsky ([e-mail])
 */

#include <linux/module.h>
#include <linux/config.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/string.h>

#include <asm/ccwdev.h>
#include <asm/cio.h>

#include "cio.h"
#include "cio_debug.h"
#include "css.h"
#include "device.h"
#include "chsc.h"
#include "ioasm.h"

int
device_is_online(struct subchannel *sch)
{
	struct ccw_device *cdev;

	if (!sch->dev.driver_data)
		return 0;
	cdev = sch->dev.driver_data;
	return (cdev->private->state == DEV_STATE_ONLINE);
}

int
device_is_disconnected(struct subchannel *sch)
{
	struct ccw_device *cdev;

	if (!sch->dev.driver_data)
		return 0;
	cdev = sch->dev.driver_data;
	return (cdev->private->state == DEV_STATE_DISCONNECTED ||
		cdev->private->state == DEV_STATE_DISCONNECTED_SENSE_ID);
}

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

	if (!sch->dev.driver_data)
		return;
	cdev = sch->dev.driver_data;
	ccw_device_set_timeout(cdev, 0);
	cdev->private->flags.fake_irb = 0;
	cdev->private->state = DEV_STATE_DISCONNECTED;
}

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

	if (!sch->dev.driver_data)
		return;
	cdev = sch->dev.driver_data;
	ccw_device_set_timeout(cdev, 10*HZ);
	cdev->private->state = DEV_STATE_WAIT4IO;
}

/*
 * Timeout function. It just triggers a DEV_EVENT_TIMEOUT.
 */
static void
ccw_device_timeout(unsigned long data)
{
	struct ccw_device *cdev;

	cdev = (struct ccw_device *) data;
	spin_lock_irq(cdev->ccwlock);
	dev_fsm_event(cdev, DEV_EVENT_TIMEOUT);
	spin_unlock_irq(cdev->ccwlock);
}

/*
 * Set timeout
 */
void
ccw_device_set_timeout(struct ccw_device *cdev, int expires)
{
	if (expires == 0) {
		del_timer(&cdev->private->timer);
		return;
	}
	if (timer_pending(&cdev->private->timer)) {
		if (mod_timer(&cdev->private->timer, jiffies + expires))
			return;
	}
	cdev->private->timer.function = ccw_device_timeout;
	cdev->private->timer.data = (unsigned long) cdev;
	cdev->private->timer.expires = jiffies + expires;
	add_timer(&cdev->private->timer);
}

/* Kill any pending timers after machine check. */
void
device_kill_pending_timer(struct subchannel *sch)
{
	struct ccw_device *cdev;

	if (!sch->dev.driver_data)
		return;
	cdev = sch->dev.driver_data;
	ccw_device_set_timeout(cdev, 0);
}

/*
 * Cancel running i/o. This is called repeatedly since halt/clear are
 * asynchronous operations. We do one try with cio_cancel, two tries
 * with cio_halt, 255 tries with cio_clear. If everythings fails panic.
 * Returns 0 if device now idle, -ENODEV for device not operational and
 * -EBUSY if an interrupt is expected (either from halt/clear or from a
 * status pending).
 */
int
ccw_device_cancel_halt_clear(struct ccw_device *cdev)
{
	struct subchannel *sch;
	int ret;

	sch = to_subchannel(cdev->dev.parent);
	ret = stsch(sch->irq, &sch->schib);
	if (ret || !sch->schib.pmcw.dnv)
		return -ENODEV; 
	if (!sch->schib.pmcw.ena || sch->schib.scsw.actl == 0)
		/* Not operational or no activity -> done. */
		return 0;
	/* Stage 1: cancel io. */
	if (!(sch->schib.scsw.actl & SCSW_ACTL_HALT_PEND) &&
	    !(sch->schib.scsw.actl & SCSW_ACTL_CLEAR_PEND)) {
		ret = cio_cancel(sch);
		if (ret != -EINVAL)
			return ret;
		/* cancel io unsuccessful. From now on it is asynchronous. */
		cdev->private->iretry = 3;	/* 3 halt retries. */
	}
	if (!(sch->schib.scsw.actl & SCSW_ACTL_CLEAR_PEND)) {
		/* Stage 2: halt io. */
		if (cdev->private->iretry) {
			cdev->private->iretry--;
			ret = cio_halt(sch);
			return (ret == 0) ? -EBUSY : ret;
		}
		/* halt io unsuccessful. */
		cdev->private->iretry = 255;	/* 255 clear retries. */
	}
	/* Stage 3: clear io. */
	if (cdev->private->iretry) {
		cdev->private->iretry--;
		ret = cio_clear (sch);
		return (ret == 0) ? -EBUSY : ret;
	}
	panic("Can't stop i/o on subchannel.\n");
}

static int
ccw_device_handle_oper(struct ccw_device *cdev)
{
	struct subchannel *sch;

	sch = to_subchannel(cdev->dev.parent);
	cdev->private->flags.recog_done = 1;
	/*
	 * Check if cu type and device type still match. If
	 * not, it is certainly another device and we have to
	 * de- and re-register. Also check here for non-matching devno.
	 */
	if (cdev->id.cu_type != cdev->private->senseid.cu_type ||
	    cdev->id.cu_model != cdev->private->senseid.cu_model ||
	    cdev->id.dev_type != cdev->private->senseid.dev_type ||
	    cdev->id.dev_model != cdev->private->senseid.dev_model ||
	    cdev->private->devno != sch->schib.pmcw.dev) {
		PREPARE_WORK(&cdev->private->kick_work,
			     ccw_device_do_unreg_rereg, (void *)cdev);
		queue_work(ccw_device_work, &cdev->private->kick_work);
		return 0;
	}
	cdev->private->flags.donotify = 1;
	return 1;
}

/*
 * The machine won't give us any notification by machine check if a chpid has
 * been varied online on the SE so we have to find out by magic (i. e. driving
 * the channel subsystem to device selection and updating our path masks).
 */
static inline void
__recover_lost_chpids(struct subchannel *sch, int old_lpm)
{
	int mask, i;

	for (i = 0; i<8; i++) {
		mask = 0x80 >> i;
		if (!(sch->lpm & mask))
			continue;
		if (old_lpm & mask)
			continue;
		chpid_is_actually_online(sch->schib.pmcw.chpid[i]);
	}
}

/*
 * Stop device recognition.
 */
static void
ccw_device_recog_done(struct ccw_device *cdev, int state)
{
	struct subchannel *sch;
	int notify, old_lpm, same_dev;

	sch = to_subchannel(cdev->dev.parent);

	ccw_device_set_timeout(cdev, 0);
	cio_disable_subchannel(sch);
	/*
	 * Now that we tried recognition, we have performed device selection
	 * through ssch() and the path information is up to date.
	 */
	old_lpm = sch->lpm;
	stsch(sch->irq, &sch->schib);
	sch->lpm = sch->schib.pmcw.pim &
		sch->schib.pmcw.pam &
		sch->schib.pmcw.pom &
		sch->opm;
	/* Check since device may again have become not operational. */
	if (!sch->schib.pmcw.dnv)
		state = DEV_STATE_NOT_OPER;
	if (cdev->private->state == DEV_STATE_DISCONNECTED_SENSE_ID)
		/* Force reprobe on all chpids. */
		old_lpm = 0;
	if (sch->lpm != old_lpm)
		__recover_lost_chpids(sch, old_lpm);
	if (cdev->private->state == DEV_STATE_DISCONNECTED_SENSE_ID) {
		if (state == DEV_STATE_NOT_OPER) {
			cdev->private->flags.recog_done = 1;
			cdev->private->state = DEV_STATE_DISCONNECTED;
			return;
		}
		/* Boxed devices don't need extra treatment. */
	}
	notify = 0;
	same_dev = 0; /* Keep the compiler quiet... */
	switch (state) {
	case DEV_STATE_NOT_OPER:
		CIO_DEBUG(KERN_WARNING, 2,
			  "SenseID : unknown device %04x on subchannel %04x\n",
			  cdev->private->devno, sch->irq);
		break;
	case DEV_STATE_OFFLINE:
		if (cdev->private->state == DEV_STATE_DISCONNECTED_SENSE_ID) {
			same_dev = ccw_device_handle_oper(cdev);
			notify = 1;
		}
		/* fill out sense information */
		cdev->id = (struct ccw_device_id) {
			.cu_type   = cdev->private->senseid.cu_type,
			.cu_model  = cdev->private->senseid.cu_model,
			.dev_type  = cdev->private->senseid.dev_type,
			.dev_model = cdev->private->senseid.dev_model,
		};
		if (notify) {
			cdev->private->state = DEV_STATE_OFFLINE;
			if (same_dev) {
				/* Get device online again. */
				ccw_device_online(cdev);
				wake_up(&cdev->private->wait_q);
			}
			return;
		}
		/* Issue device info message. */
		CIO_DEBUG(KERN_INFO, 2, "SenseID : device %04x reports: "
			  "CU  Type/Mod = %04X/%02X, Dev Type/Mod = "
			  "%04X/%02X\n", cdev->private->devno,
			  cdev->id.cu_type, cdev->id.cu_model,
			  cdev->id.dev_type, cdev->id.dev_model);
		break;
	case DEV_STATE_BOXED:
		CIO_DEBUG(KERN_WARNING, 2,
			  "SenseID : boxed device %04x on subchannel %04x\n",
			  cdev->private->devno, sch->irq);
		break;
	}
	cdev->private->state = state;
	io_subchannel_recog_done(cdev);
	if (state != DEV_STATE_NOT_OPER)
		wake_up(&cdev->private->wait_q);
}

/*
 * Function called from device_id.c after sense id has completed.
 */
void
ccw_device_sense_id_done(struct ccw_device *cdev, int err)
{
	switch (err) {
	case 0:
		ccw_device_recog_done(cdev, DEV_STATE_OFFLINE);
		break;
	case -ETIME:		/* Sense id stopped by timeout. */
		ccw_device_recog_done(cdev, DEV_STATE_BOXED);
		break;
	default:
		ccw_device_recog_done(cdev, DEV_STATE_NOT_OPER);
		break;
	}
}

static void
ccw_device_oper_notify(void *data)
{
	struct ccw_device *cdev;
	struct subchannel *sch;
	int ret;

	cdev = (struct ccw_device *)data;
	sch = to_subchannel(cdev->dev.parent);
	ret = (sch->driver && sch->driver->notify) ?
		sch->driver->notify(&sch->dev, CIO_OPER) : 0;
	if (!ret)
		/* Driver doesn't want device back. */
		ccw_device_do_unreg_rereg((void *)cdev);
	else
		wake_up(&cdev->private->wait_q);
}

/*
 * Finished with online/offline processing.
 */
static void
ccw_device_done(struct ccw_device *cdev, int state)
{
	struct subchannel *sch;

	sch = to_subchannel(cdev->dev.parent);

	if (state != DEV_STATE_ONLINE)
		cio_disable_subchannel(sch);

	/* Reset device status. */
	memset(&cdev->private->irb, 0, sizeof(struct irb));

	cdev->private->state = state;


	if (state == DEV_STATE_BOXED)
		CIO_DEBUG(KERN_WARNING, 2,
			  "Boxed device %04x on subchannel %04x\n",
			  cdev->private->devno, sch->irq);

	if (cdev->private->flags.donotify) {
		cdev->private->flags.donotify = 0;
		PREPARE_WORK(&cdev->private->kick_work, ccw_device_oper_notify,
			     (void *)cdev);
		queue_work(ccw_device_notify_work, &cdev->private->kick_work);
	}
	wake_up(&cdev->private->wait_q);

	if (css_init_done && state != DEV_STATE_ONLINE)
		put_device (&cdev->dev);
}

/*
 * Function called from device_pgid.c after sense path ground has completed.
 */
void
ccw_device_sense_pgid_done(struct ccw_device *cdev, int err)
{
	struct subchannel *sch;

	sch = to_subchannel(cdev->dev.parent);
	switch (err) {
	case 0:
		/* Start Path Group verification. */
		sch->vpm = 0;	/* Start with no path groups set. */
		cdev->private->state = DEV_STATE_VERIFY;
		ccw_device_verify_start(cdev);
		break;
	case -ETIME:		/* Sense path group id stopped by timeout. */
	case -EUSERS:		/* device is reserved for someone else. */
		ccw_device_done(cdev, DEV_STATE_BOXED);
		break;
	case -EOPNOTSUPP: /* path grouping not supported, just set online. */
		cdev->private->options.pgroup = 0;
		ccw_device_done(cdev, DEV_STATE_ONLINE);
		break;
	default:
		ccw_device_done(cdev, DEV_STATE_NOT_OPER);
		break;
	}
}

/*
 * Start device recognition.
 */
int
ccw_device_recognition(struct ccw_device *cdev)
{
	struct subchannel *sch;
	int ret;

	if ((cdev->private->state != DEV_STATE_NOT_OPER) &&
	    (cdev->private->state != DEV_STATE_BOXED))
		return -EINVAL;
	sch = to_subchannel(cdev->dev.parent);
	ret = cio_enable_subchannel(sch, sch->schib.pmcw.isc);