chp.c

linux 内核源代码

	if (chp->cmg == -1) /* channel measurements not available */
		return sprintf(buf, "unknown\n");
	return sprintf(buf, "%x\n", chp->cmg);
}

static DEVICE_ATTR(cmg, 0444, chp_cmg_show, NULL);

static ssize_t chp_shared_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	struct channel_path *chp = to_channelpath(dev);

	if (!chp)
		return 0;
	if (chp->shared == -1) /* channel measurements not available */
		return sprintf(buf, "unknown\n");
	return sprintf(buf, "%x\n", chp->shared);
}

static DEVICE_ATTR(shared, 0444, chp_shared_show, NULL);

static struct attribute *chp_attrs[] = {
	&dev_attr_status.attr,
	&dev_attr_configure.attr,
	&dev_attr_type.attr,
	&dev_attr_cmg.attr,
	&dev_attr_shared.attr,
	NULL,
};

static struct attribute_group chp_attr_group = {
	.attrs = chp_attrs,
};

static void chp_release(struct device *dev)
{
	struct channel_path *cp;

	cp = to_channelpath(dev);
	kfree(cp);
}

/**
 * chp_new - register a new channel-path
 * @chpid - channel-path ID
 *
 * Create and register data structure representing new channel-path. Return
 * zero on success, non-zero otherwise.
 */
int chp_new(struct chp_id chpid)
{
	struct channel_path *chp;
	int ret;

	if (chp_is_registered(chpid))
		return 0;
	chp = kzalloc(sizeof(struct channel_path), GFP_KERNEL);
	if (!chp)
		return -ENOMEM;

	/* fill in status, etc. */
	chp->chpid = chpid;
	chp->state = 1;
	chp->dev.parent = &channel_subsystems[chpid.cssid]->device;
	chp->dev.release = chp_release;
	snprintf(chp->dev.bus_id, BUS_ID_SIZE, "chp%x.%02x", chpid.cssid,
		 chpid.id);

	/* Obtain channel path description and fill it in. */
	ret = chsc_determine_channel_path_description(chpid, &chp->desc);
	if (ret)
		goto out_free;
	if ((chp->desc.flags & 0x80) == 0) {
		ret = -ENODEV;
		goto out_free;
	}
	/* Get channel-measurement characteristics. */
	if (css_characteristics_avail && css_chsc_characteristics.scmc
	    && css_chsc_characteristics.secm) {
		ret = chsc_get_channel_measurement_chars(chp);
		if (ret)
			goto out_free;
	} else {
		chp->cmg = -1;
	}

	/* make it known to the system */
	ret = device_register(&chp->dev);
	if (ret) {
		CIO_MSG_EVENT(0, "Could not register chp%x.%02x: %d\n",
			      chpid.cssid, chpid.id, ret);
		goto out_free;
	}
	ret = sysfs_create_group(&chp->dev.kobj, &chp_attr_group);
	if (ret) {
		device_unregister(&chp->dev);
		goto out_free;
	}
	mutex_lock(&channel_subsystems[chpid.cssid]->mutex);
	if (channel_subsystems[chpid.cssid]->cm_enabled) {
		ret = chp_add_cmg_attr(chp);
		if (ret) {
			sysfs_remove_group(&chp->dev.kobj, &chp_attr_group);
			device_unregister(&chp->dev);
			mutex_unlock(&channel_subsystems[chpid.cssid]->mutex);
			goto out_free;
		}
	}
	channel_subsystems[chpid.cssid]->chps[chpid.id] = chp;
	mutex_unlock(&channel_subsystems[chpid.cssid]->mutex);
	return ret;
out_free:
	kfree(chp);
	return ret;
}

/**
 * chp_get_chp_desc - return newly allocated channel-path description
 * @chpid: channel-path ID
 *
 * On success return a newly allocated copy of the channel-path description
 * data associated with the given channel-path ID. Return %NULL on error.
 */
void *chp_get_chp_desc(struct chp_id chpid)
{
	struct channel_path *chp;
	struct channel_path_desc *desc;

	chp = chpid_to_chp(chpid);
	if (!chp)
		return NULL;
	desc = kmalloc(sizeof(struct channel_path_desc), GFP_KERNEL);
	if (!desc)
		return NULL;
	memcpy(desc, &chp->desc, sizeof(struct channel_path_desc));
	return desc;
}

/**
 * chp_process_crw - process channel-path status change
 * @id: channel-path ID number
 * @status: non-zero if channel-path has become available, zero otherwise
 *
 * Handle channel-report-words indicating that the status of a channel-path
 * has changed.
 */
void chp_process_crw(int id, int status)
{
	struct chp_id chpid;

	chp_id_init(&chpid);
	chpid.id = id;
	if (status) {
		if (!chp_is_registered(chpid))
			chp_new(chpid);
		chsc_chp_online(chpid);
	} else
		chsc_chp_offline(chpid);
}

static inline int info_bit_num(struct chp_id id)
{
	return id.id + id.cssid * (__MAX_CHPID + 1);
}

/* Force chp_info refresh on next call to info_validate(). */
static void info_expire(void)
{
	mutex_lock(&info_lock);
	chp_info_expires = jiffies - 1;
	mutex_unlock(&info_lock);
}

/* Ensure that chp_info is up-to-date. */
static int info_update(void)
{
	int rc;

	mutex_lock(&info_lock);
	rc = 0;
	if (time_after(jiffies, chp_info_expires)) {
		/* Data is too old, update. */
		rc = sclp_chp_read_info(&chp_info);
		chp_info_expires = jiffies + CHP_INFO_UPDATE_INTERVAL ;
	}
	mutex_unlock(&info_lock);

	return rc;
}

/**
 * chp_info_get_status - retrieve configure status of a channel-path
 * @chpid: channel-path ID
 *
 * On success, return 0 for standby, 1 for configured, 2 for reserved,
 * 3 for not recognized. Return negative error code on error.
 */
int chp_info_get_status(struct chp_id chpid)
{
	int rc;
	int bit;

	rc = info_update();
	if (rc)
		return rc;

	bit = info_bit_num(chpid);
	mutex_lock(&info_lock);
	if (!chp_test_bit(chp_info.recognized, bit))
		rc = CHP_STATUS_NOT_RECOGNIZED;
	else if (chp_test_bit(chp_info.configured, bit))
		rc = CHP_STATUS_CONFIGURED;
	else if (chp_test_bit(chp_info.standby, bit))
		rc = CHP_STATUS_STANDBY;
	else
		rc = CHP_STATUS_RESERVED;
	mutex_unlock(&info_lock);

	return rc;
}

/* Return configure task for chpid. */
static enum cfg_task_t cfg_get_task(struct chp_id chpid)
{
	return chp_cfg_task[chpid.cssid][chpid.id];
}

/* Set configure task for chpid. */
static void cfg_set_task(struct chp_id chpid, enum cfg_task_t cfg)
{
	chp_cfg_task[chpid.cssid][chpid.id] = cfg;
}

/* Perform one configure/deconfigure request. Reschedule work function until
 * last request. */
static void cfg_func(struct work_struct *work)
{
	struct chp_id chpid;
	enum cfg_task_t t;

	mutex_lock(&cfg_lock);
	t = cfg_none;
	chp_id_for_each(&chpid) {
		t = cfg_get_task(chpid);
		if (t != cfg_none) {
			cfg_set_task(chpid, cfg_none);
			break;
		}
	}
	mutex_unlock(&cfg_lock);

	switch (t) {
	case cfg_configure:
		sclp_chp_configure(chpid);
		info_expire();
		chsc_chp_online(chpid);
		break;
	case cfg_deconfigure:
		sclp_chp_deconfigure(chpid);
		info_expire();
		chsc_chp_offline(chpid);
		break;
	case cfg_none:
		/* Get updated information after last change. */
		info_update();
		mutex_lock(&cfg_lock);
		cfg_busy = 0;
		mutex_unlock(&cfg_lock);
		wake_up_interruptible(&cfg_wait_queue);
		return;
	}
	queue_work(chp_wq, &cfg_work);
}

/**
 * chp_cfg_schedule - schedule chpid configuration request
 * @chpid - channel-path ID
 * @configure - Non-zero for configure, zero for deconfigure
 *
 * Schedule a channel-path configuration/deconfiguration request.
 */
void chp_cfg_schedule(struct chp_id chpid, int configure)
{
	CIO_MSG_EVENT(2, "chp_cfg_sched%x.%02x=%d\n", chpid.cssid, chpid.id,
		      configure);
	mutex_lock(&cfg_lock);
	cfg_set_task(chpid, configure ? cfg_configure : cfg_deconfigure);
	cfg_busy = 1;
	mutex_unlock(&cfg_lock);
	queue_work(chp_wq, &cfg_work);
}

/**
 * chp_cfg_cancel_deconfigure - cancel chpid deconfiguration request
 * @chpid - channel-path ID
 *
 * Cancel an active channel-path deconfiguration request if it has not yet
 * been performed.
 */
void chp_cfg_cancel_deconfigure(struct chp_id chpid)
{
	CIO_MSG_EVENT(2, "chp_cfg_cancel:%x.%02x\n", chpid.cssid, chpid.id);
	mutex_lock(&cfg_lock);
	if (cfg_get_task(chpid) == cfg_deconfigure)
		cfg_set_task(chpid, cfg_none);
	mutex_unlock(&cfg_lock);
}

static int cfg_wait_idle(void)
{
	if (wait_event_interruptible(cfg_wait_queue, !cfg_busy))
		return -ERESTARTSYS;
	return 0;
}

static int __init chp_init(void)
{
	struct chp_id chpid;

	chp_wq = create_singlethread_workqueue("cio_chp");
	if (!chp_wq)
		return -ENOMEM;
	INIT_WORK(&cfg_work, cfg_func);
	init_waitqueue_head(&cfg_wait_queue);
	if (info_update())
		return 0;
	/* Register available channel-paths. */
	chp_id_for_each(&chpid) {
		if (chp_info_get_status(chpid) != CHP_STATUS_NOT_RECOGNIZED)
			chp_new(chpid);
	}

	return 0;
}

subsys_initcall(chp_init);