css.c

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	unsigned long flags;

	spin_lock_irqsave(&slow_subchannel_lock, flags);
	idset_fill(slow_subchannel_set);
	queue_work(slow_path_wq, &slow_path_work);
	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
}

/* Reprobe subchannel if unregistered. */
static int reprobe_subchannel(struct subchannel_id schid, void *data)
{
	struct subchannel *sch;
	int ret;

	CIO_MSG_EVENT(6, "cio: reprobe 0.%x.%04x\n",
		      schid.ssid, schid.sch_no);
	if (need_reprobe)
		return -EAGAIN;

	sch = get_subchannel_by_schid(schid);
	if (sch) {
		/* Already known. */
		put_device(&sch->dev);
		return 0;
	}

	ret = css_probe_device(schid);
	switch (ret) {
	case 0:
		break;
	case -ENXIO:
	case -ENOMEM:
	case -EIO:
		/* These should abort looping */
		break;
	default:
		ret = 0;
	}

	return ret;
}

/* Work function used to reprobe all unregistered subchannels. */
static void reprobe_all(struct work_struct *unused)
{
	int ret;

	CIO_MSG_EVENT(2, "reprobe start\n");

	need_reprobe = 0;
	/* Make sure initial subchannel scan is done. */
	wait_event(ccw_device_init_wq,
		   atomic_read(&ccw_device_init_count) == 0);
	ret = for_each_subchannel(reprobe_subchannel, NULL);

	CIO_MSG_EVENT(2, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
		      need_reprobe);
}

static DECLARE_WORK(css_reprobe_work, reprobe_all);

/* Schedule reprobing of all unregistered subchannels. */
void css_schedule_reprobe(void)
{
	need_reprobe = 1;
	queue_work(slow_path_wq, &css_reprobe_work);
}

EXPORT_SYMBOL_GPL(css_schedule_reprobe);

/*
 * Called from the machine check handler for subchannel report words.
 */
void css_process_crw(int rsid1, int rsid2)
{
	struct subchannel_id mchk_schid;

	CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
		      rsid1, rsid2);
	init_subchannel_id(&mchk_schid);
	mchk_schid.sch_no = rsid1;
	if (rsid2 != 0)
		mchk_schid.ssid = (rsid2 >> 8) & 3;

	/* 
	 * Since we are always presented with IPI in the CRW, we have to
	 * use stsch() to find out if the subchannel in question has come
	 * or gone.
	 */
	css_evaluate_subchannel(mchk_schid, 0);
}

static int __init
__init_channel_subsystem(struct subchannel_id schid, void *data)
{
	struct subchannel *sch;
	int ret;

	if (cio_is_console(schid))
		sch = cio_get_console_subchannel();
	else {
		sch = css_alloc_subchannel(schid);
		if (IS_ERR(sch))
			ret = PTR_ERR(sch);
		else
			ret = 0;
		switch (ret) {
		case 0:
			break;
		case -ENOMEM:
			panic("Out of memory in init_channel_subsystem\n");
		/* -ENXIO: no more subchannels. */
		case -ENXIO:
			return ret;
		/* -EIO: this subchannel set not supported. */
		case -EIO:
			return ret;
		default:
			return 0;
		}
	}
	/*
	 * We register ALL valid subchannels in ioinfo, even those
	 * that have been present before init_channel_subsystem.
	 * These subchannels can't have been registered yet (kmalloc
	 * not working) so we do it now. This is true e.g. for the
	 * console subchannel.
	 */
	css_register_subchannel(sch);
	return 0;
}

static void __init
css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
{
	if (css_characteristics_avail && css_general_characteristics.mcss) {
		css->global_pgid.pgid_high.ext_cssid.version = 0x80;
		css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
	} else {
#ifdef CONFIG_SMP
		css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
#else
		css->global_pgid.pgid_high.cpu_addr = 0;
#endif
	}
	css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
	css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
	css->global_pgid.tod_high = tod_high;

}

static void
channel_subsystem_release(struct device *dev)
{
	struct channel_subsystem *css;

	css = to_css(dev);
	mutex_destroy(&css->mutex);
	kfree(css);
}

static ssize_t
css_cm_enable_show(struct device *dev, struct device_attribute *attr,
		   char *buf)
{
	struct channel_subsystem *css = to_css(dev);

	if (!css)
		return 0;
	return sprintf(buf, "%x\n", css->cm_enabled);
}

static ssize_t
css_cm_enable_store(struct device *dev, struct device_attribute *attr,
		    const char *buf, size_t count)
{
	struct channel_subsystem *css = to_css(dev);
	int ret;

	switch (buf[0]) {
	case '0':
		ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
		break;
	case '1':
		ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
		break;
	default:
		ret = -EINVAL;
	}
	return ret < 0 ? ret : count;
}

static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);

static int __init setup_css(int nr)
{
	u32 tod_high;
	int ret;
	struct channel_subsystem *css;

	css = channel_subsystems[nr];
	memset(css, 0, sizeof(struct channel_subsystem));
	css->pseudo_subchannel =
		kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
	if (!css->pseudo_subchannel)
		return -ENOMEM;
	css->pseudo_subchannel->dev.parent = &css->device;
	css->pseudo_subchannel->dev.release = css_subchannel_release;
	sprintf(css->pseudo_subchannel->dev.bus_id, "defunct");
	ret = cio_create_sch_lock(css->pseudo_subchannel);
	if (ret) {
		kfree(css->pseudo_subchannel);
		return ret;
	}
	mutex_init(&css->mutex);
	css->valid = 1;
	css->cssid = nr;
	sprintf(css->device.bus_id, "css%x", nr);
	css->device.release = channel_subsystem_release;
	tod_high = (u32) (get_clock() >> 32);
	css_generate_pgid(css, tod_high);
	return 0;
}

static int css_reboot_event(struct notifier_block *this,
			    unsigned long event,
			    void *ptr)
{
	int ret, i;

	ret = NOTIFY_DONE;
	for (i = 0; i <= __MAX_CSSID; i++) {
		struct channel_subsystem *css;

		css = channel_subsystems[i];
		if (css->cm_enabled)
			if (chsc_secm(css, 0))
				ret = NOTIFY_BAD;
	}

	return ret;
}

static struct notifier_block css_reboot_notifier = {
	.notifier_call = css_reboot_event,
};

/*
 * Now that the driver core is running, we can setup our channel subsystem.
 * The struct subchannel's are created during probing (except for the
 * static console subchannel).
 */
static int __init
init_channel_subsystem (void)
{
	int ret, i;

	ret = chsc_determine_css_characteristics();
	if (ret == -ENOMEM)
		goto out; /* No need to continue. */
	if (ret == 0)
		css_characteristics_avail = 1;

	ret = chsc_alloc_sei_area();
	if (ret)
		goto out;

	ret = slow_subchannel_init();
	if (ret)
		goto out;

	if ((ret = bus_register(&css_bus_type)))
		goto out;

	/* Try to enable MSS. */
	ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
	switch (ret) {
	case 0: /* Success. */
		max_ssid = __MAX_SSID;
		break;
	case -ENOMEM:
		goto out_bus;
	default:
		max_ssid = 0;
	}
	/* Setup css structure. */
	for (i = 0; i <= __MAX_CSSID; i++) {
		struct channel_subsystem *css;

		css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
		if (!css) {
			ret = -ENOMEM;
			goto out_unregister;
		}
		channel_subsystems[i] = css;
		ret = setup_css(i);
		if (ret)
			goto out_free;
		ret = device_register(&css->device);
		if (ret)
			goto out_free_all;
		if (css_characteristics_avail &&
		    css_chsc_characteristics.secm) {
			ret = device_create_file(&css->device,
						 &dev_attr_cm_enable);
			if (ret)
				goto out_device;
		}
		ret = device_register(&css->pseudo_subchannel->dev);
		if (ret)
			goto out_file;
	}
	ret = register_reboot_notifier(&css_reboot_notifier);
	if (ret)
		goto out_pseudo;
	css_init_done = 1;

	ctl_set_bit(6, 28);

	for_each_subchannel(__init_channel_subsystem, NULL);
	return 0;
out_pseudo:
	device_unregister(&channel_subsystems[i]->pseudo_subchannel->dev);
out_file:
	device_remove_file(&channel_subsystems[i]->device,
			   &dev_attr_cm_enable);
out_device:
	device_unregister(&channel_subsystems[i]->device);
out_free_all:
	kfree(channel_subsystems[i]->pseudo_subchannel->lock);
	kfree(channel_subsystems[i]->pseudo_subchannel);
out_free:
	kfree(channel_subsystems[i]);
out_unregister:
	while (i > 0) {
		struct channel_subsystem *css;

		i--;
		css = channel_subsystems[i];
		device_unregister(&css->pseudo_subchannel->dev);
		if (css_characteristics_avail && css_chsc_characteristics.secm)
			device_remove_file(&css->device,
					   &dev_attr_cm_enable);
		device_unregister(&css->device);
	}
out_bus:
	bus_unregister(&css_bus_type);
out:
	chsc_free_sei_area();
	kfree(slow_subchannel_set);
	printk(KERN_WARNING"cio: failed to initialize css driver (%d)!\n",
	       ret);
	return ret;
}

int sch_is_pseudo_sch(struct subchannel *sch)
{
	return sch == to_css(sch->dev.parent)->pseudo_subchannel;
}

/*
 * find a driver for a subchannel. They identify by the subchannel
 * type with the exception that the console subchannel driver has its own
 * subchannel type although the device is an i/o subchannel
 */
static int
css_bus_match (struct device *dev, struct device_driver *drv)
{
	struct subchannel *sch = container_of (dev, struct subchannel, dev);
	struct css_driver *driver = container_of (drv, struct css_driver, drv);

	if (sch->st == driver->subchannel_type)
		return 1;

	return 0;
}

static int
css_probe (struct device *dev)
{
	struct subchannel *sch;

	sch = to_subchannel(dev);
	sch->driver = container_of (dev->driver, struct css_driver, drv);
	return (sch->driver->probe ? sch->driver->probe(sch) : 0);
}

static int
css_remove (struct device *dev)
{
	struct subchannel *sch;

	sch = to_subchannel(dev);
	return (sch->driver->remove ? sch->driver->remove(sch) : 0);
}

static void
css_shutdown (struct device *dev)
{
	struct subchannel *sch;

	sch = to_subchannel(dev);
	if (sch->driver->shutdown)
		sch->driver->shutdown(sch);
}

struct bus_type css_bus_type = {
	.name     = "css",
	.match    = css_bus_match,
	.probe    = css_probe,
	.remove   = css_remove,
	.shutdown = css_shutdown,
};

subsys_initcall(init_channel_subsystem);

MODULE_LICENSE("GPL");
EXPORT_SYMBOL(css_bus_type);
EXPORT_SYMBOL_GPL(css_characteristics_avail);