[deliverable/linux.git] / drivers / s390 / cio / css.c

/*
 *  drivers/s390/cio/css.c
 *  driver for channel subsystem
 *
 *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
 *			 IBM Corporation
 *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
 *		 Cornelia Huck (cornelia.huck@de.ibm.com)
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/list.h>

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

int need_rescan = 0;
int css_init_done = 0;
static int max_ssid = 0;

struct channel_subsystem *css[__MAX_CSSID + 1];

int css_characteristics_avail = 0;

inline int
for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
{
	struct subchannel_id schid;
	int ret;

	init_subchannel_id(&schid);
	ret = -ENODEV;
	do {
		do {
			ret = fn(schid, data);
			if (ret)
				break;
		} while (schid.sch_no++ < __MAX_SUBCHANNEL);
		schid.sch_no = 0;
	} while (schid.ssid++ < max_ssid);
	return ret;
}

static struct subchannel *
css_alloc_subchannel(struct subchannel_id schid)
{
	struct subchannel *sch;
	int ret;

	sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
	if (sch == NULL)
		return ERR_PTR(-ENOMEM);
	ret = cio_validate_subchannel (sch, schid);
	if (ret < 0) {
		kfree(sch);
		return ERR_PTR(ret);
	}

	if (sch->st != SUBCHANNEL_TYPE_IO) {
		/* For now we ignore all non-io subchannels. */
		kfree(sch);
		return ERR_PTR(-EINVAL);
	}

	/* 
	 * Set intparm to subchannel address.
	 * This is fine even on 64bit since the subchannel is always located
	 * under 2G.
	 */
	sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
	ret = cio_modify(sch);
	if (ret) {
		kfree(sch);
		return ERR_PTR(ret);
	}
	return sch;
}

static void
css_free_subchannel(struct subchannel *sch)
{
	if (sch) {
		/* Reset intparm to zeroes. */
		sch->schib.pmcw.intparm = 0;
		cio_modify(sch);
		kfree(sch);
	}
	
}

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

	sch = to_subchannel(dev);
	if (!cio_is_console(sch->schid))
		kfree(sch);
}

extern int css_get_ssd_info(struct subchannel *sch);

static int
css_register_subchannel(struct subchannel *sch)
{
	int ret;

	/* Initialize the subchannel structure */
	sch->dev.parent = &css[0]->device;
	sch->dev.bus = &css_bus_type;
	sch->dev.release = &css_subchannel_release;
	
	/* make it known to the system */
	ret = device_register(&sch->dev);
	if (ret)
		printk (KERN_WARNING "%s: could not register %s\n",
			__func__, sch->dev.bus_id);
	else
		css_get_ssd_info(sch);
	return ret;
}

int
css_probe_device(struct subchannel_id schid)
{
	int ret;
	struct subchannel *sch;

	sch = css_alloc_subchannel(schid);
	if (IS_ERR(sch))
		return PTR_ERR(sch);
	ret = css_register_subchannel(sch);
	if (ret)
		css_free_subchannel(sch);
	return ret;
}

static int
check_subchannel(struct device * dev, void * data)
{
	struct subchannel *sch;
	struct subchannel_id *schid = data;

	sch = to_subchannel(dev);
	return schid_equal(&sch->schid, schid);
}

struct subchannel *
get_subchannel_by_schid(struct subchannel_id schid)
{
	struct device *dev;

	dev = bus_find_device(&css_bus_type, NULL,
			      (void *)&schid, check_subchannel);

	return dev ? to_subchannel(dev) : NULL;
}


static inline int
css_get_subchannel_status(struct subchannel *sch, struct subchannel_id schid)
{
	struct schib schib;
	int cc;

	cc = stsch(schid, &schib);
	if (cc)
		return CIO_GONE;
	if (!schib.pmcw.dnv)
		return CIO_GONE;
	if (sch && sch->schib.pmcw.dnv &&
	    (schib.pmcw.dev != sch->schib.pmcw.dev))
		return CIO_REVALIDATE;
	if (sch && !sch->lpm)
		return CIO_NO_PATH;
	return CIO_OPER;
}
	
static int
css_evaluate_subchannel(struct subchannel_id schid, int slow)
{
	int event, ret, disc;
	struct subchannel *sch;
	unsigned long flags;

	sch = get_subchannel_by_schid(schid);
	disc = sch ? device_is_disconnected(sch) : 0;
	if (disc && slow) {
		if (sch)
			put_device(&sch->dev);
		return 0; /* Already processed. */
	}
	/*
	 * We've got a machine check, so running I/O won't get an interrupt.
	 * Kill any pending timers.
	 */
	if (sch)
		device_kill_pending_timer(sch);
	if (!disc && !slow) {
		if (sch)
			put_device(&sch->dev);
		return -EAGAIN; /* Will be done on the slow path. */
	}
	event = css_get_subchannel_status(sch, schid);
	CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
		      schid.ssid, schid.sch_no, event,
		      sch?(disc?"disconnected":"normal"):"unknown",
		      slow?"slow":"fast");
	switch (event) {
	case CIO_NO_PATH:
	case CIO_GONE:
		if (!sch) {
			/* Never used this subchannel. Ignore. */
			ret = 0;
			break;
		}
		if (disc && (event == CIO_NO_PATH)) {
			/*
			 * Uargh, hack again. Because we don't get a machine
			 * check on configure on, our path bookkeeping can
			 * be out of date here (it's fine while we only do
			 * logical varying or get chsc machine checks). We
			 * need to force reprobing or we might miss devices
			 * coming operational again. It won't do harm in real
			 * no path situations.
			 */
			spin_lock_irqsave(&sch->lock, flags);
			device_trigger_reprobe(sch);
			spin_unlock_irqrestore(&sch->lock, flags);
			ret = 0;
			break;
		}
		if (sch->driver && sch->driver->notify &&
		    sch->driver->notify(&sch->dev, event)) {
			cio_disable_subchannel(sch);
			device_set_disconnected(sch);
			ret = 0;
			break;
		}
		/*
		 * Unregister subchannel.
		 * The device will be killed automatically.
		 */
		cio_disable_subchannel(sch);
		device_unregister(&sch->dev);
		/* Reset intparm to zeroes. */
		sch->schib.pmcw.intparm = 0;
		cio_modify(sch);
		put_device(&sch->dev);
		ret = 0;
		break;
	case CIO_REVALIDATE:
		/* 
		 * Revalidation machine check. Sick.
		 * We don't notify the driver since we have to throw the device
		 * away in any case.
		 */
		if (!disc) {
			device_unregister(&sch->dev);
			/* Reset intparm to zeroes. */
			sch->schib.pmcw.intparm = 0;
			cio_modify(sch);
			put_device(&sch->dev);
			ret = css_probe_device(schid);
		} else {
			/*
			 * We can't immediately deregister the disconnected
			 * device since it might block.
			 */
			spin_lock_irqsave(&sch->lock, flags);
			device_trigger_reprobe(sch);
			spin_unlock_irqrestore(&sch->lock, flags);
			ret = 0;
		}
		break;
	case CIO_OPER:
		if (disc) {
			spin_lock_irqsave(&sch->lock, flags);
			/* Get device operational again. */
			device_trigger_reprobe(sch);
			spin_unlock_irqrestore(&sch->lock, flags);
		}
		ret = sch ? 0 : css_probe_device(schid);
		break;
	default:
		BUG();
		ret = 0;
	}
	return ret;
}

static int
css_rescan_devices(struct subchannel_id schid, void *data)
{
	return css_evaluate_subchannel(schid, 1);
}

struct slow_subchannel {
	struct list_head slow_list;
	struct subchannel_id schid;
};

static LIST_HEAD(slow_subchannels_head);
static DEFINE_SPINLOCK(slow_subchannel_lock);

static void
css_trigger_slow_path(void)
{
	CIO_TRACE_EVENT(4, "slowpath");

	if (need_rescan) {
		need_rescan = 0;
		for_each_subchannel(css_rescan_devices, NULL);
		return;
	}

	spin_lock_irq(&slow_subchannel_lock);
	while (!list_empty(&slow_subchannels_head)) {
		struct slow_subchannel *slow_sch =
			list_entry(slow_subchannels_head.next,
				   struct slow_subchannel, slow_list);

		list_del_init(slow_subchannels_head.next);
		spin_unlock_irq(&slow_subchannel_lock);
		css_evaluate_subchannel(slow_sch->schid, 1);
		spin_lock_irq(&slow_subchannel_lock);
		kfree(slow_sch);
	}
	spin_unlock_irq(&slow_subchannel_lock);
}

typedef void (*workfunc)(void *);
DECLARE_WORK(slow_path_work, (workfunc)css_trigger_slow_path, NULL);
struct workqueue_struct *slow_path_wq;

/*
 * Rescan for new devices. FIXME: This is slow.
 * This function is called when we have lost CRWs due to overflows and we have
 * to do subchannel housekeeping.
 */
void
css_reiterate_subchannels(void)
{
	css_clear_subchannel_slow_list();
	need_rescan = 1;
}

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

	CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
		      rsid1, rsid2);

	if (need_rescan)
		/* We need to iterate all subchannels anyway. */
		return -EAGAIN;

	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.
	 */
	ret = css_evaluate_subchannel(mchk_schid, 0);
	if (ret == -EAGAIN) {
		if (css_enqueue_subchannel_slow(mchk_schid)) {
			css_clear_subchannel_slow_list();
			need_rescan = 1;
		}
	}
	return ret;
}

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;
		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);
	kfree(css);
}

static inline void __init
setup_css(int nr)
{
	u32 tod_high;

	memset(css[nr], 0, sizeof(struct channel_subsystem));
	css[nr]->valid = 1;
	css[nr]->cssid = nr;
	sprintf(css[nr]->device.bus_id, "css%x", nr);
	css[nr]->device.release = channel_subsystem_release;
	tod_high = (u32) (get_clock() >> 32);
	css_generate_pgid(css[nr], tod_high);
}

/*
 * 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;

	if (chsc_determine_css_characteristics() == 0)
		css_characteristics_avail = 1;

	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++) {
		css[i] = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
		if (!css[i]) {
			ret = -ENOMEM;
			goto out_unregister;
		}
		setup_css(i);
		ret = device_register(&css[i]->device);
		if (ret)
			goto out_free;
	}
	css_init_done = 1;

	ctl_set_bit(6, 28);

	for_each_subchannel(__init_channel_subsystem, NULL);
	return 0;
out_free:
	kfree(css[i]);
out_unregister:
	while (i > 0) {
		i--;
		device_unregister(&css[i]->device);
	}
out_bus:
	bus_unregister(&css_bus_type);
out:
	return ret;
}

/*
 * 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);

int
css_enqueue_subchannel_slow(struct subchannel_id schid)
{
	struct slow_subchannel *new_slow_sch;
	unsigned long flags;

	new_slow_sch = kmalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
	if (!new_slow_sch)
		return -ENOMEM;
	memset(new_slow_sch, 0, sizeof(struct slow_subchannel));
	new_slow_sch->schid = schid;
	spin_lock_irqsave(&slow_subchannel_lock, flags);
	list_add_tail(&new_slow_sch->slow_list, &slow_subchannels_head);
	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
	return 0;
}

void
css_clear_subchannel_slow_list(void)
{
	unsigned long flags;

	spin_lock_irqsave(&slow_subchannel_lock, flags);
	while (!list_empty(&slow_subchannels_head)) {
		struct slow_subchannel *slow_sch =
			list_entry(slow_subchannels_head.next,
				   struct slow_subchannel, slow_list);

		list_del_init(slow_subchannels_head.next);
		kfree(slow_sch);
	}
	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
}


int
css_slow_subchannels_exist(void)
{
	return (!list_empty(&slow_subchannels_head));
}

MODULE_LICENSE("GPL");
EXPORT_SYMBOL(css_bus_type);
EXPORT_SYMBOL_GPL(css_characteristics_avail);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* drivers/s390/cio/css.c
	3	* driver for channel subsystem
1da177e4 LT	4	*
	5	* Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
	6	* IBM Corporation
	7	* Author(s): Arnd Bergmann (arndb@de.ibm.com)
4ce3b30c	8	* Cornelia Huck (cornelia.huck@de.ibm.com)
1da177e4 LT	9	*/
	10	#include <linux/module.h>
	11	#include <linux/init.h>
	12	#include <linux/device.h>
	13	#include <linux/slab.h>
	14	#include <linux/errno.h>
	15	#include <linux/list.h>
	16
	17	#include "css.h"
	18	#include "cio.h"
	19	#include "cio_debug.h"
	20	#include "ioasm.h"
	21	#include "chsc.h"
	22
1da177e4 LT	23	int need_rescan = 0;
1da177e4 LT	24	int css_init_done = 0;
fb6958a5	25	static int max_ssid = 0;
1da177e4	26
a28c6944	27	struct channel_subsystem *css[__MAX_CSSID + 1];
1da177e4	28
a28c6944	29	int css_characteristics_avail = 0;
1da177e4	30
f97a56fb CH	31	inline int
	32	for_each_subchannel(int(fn)(struct subchannel_id, void ), void *data)
	33	{
	34	struct subchannel_id schid;
	35	int ret;
	36
	37	init_subchannel_id(&schid);
	38	ret = -ENODEV;
	39	do {
fb6958a5 CH	40	do {
	41	ret = fn(schid, data);
	42	if (ret)
	43	break;
	44	} while (schid.sch_no++ < __MAX_SUBCHANNEL);
	45	schid.sch_no = 0;
	46	} while (schid.ssid++ < max_ssid);
f97a56fb CH	47	return ret;
	48	}
	49
1da177e4	50	static struct subchannel *
a8237fc4	51	css_alloc_subchannel(struct subchannel_id schid)
1da177e4 LT	52	{
	53	struct subchannel *sch;
	54	int ret;
	55
	56	sch = kmalloc (sizeof (*sch), GFP_KERNEL \| GFP_DMA);
	57	if (sch == NULL)
	58	return ERR_PTR(-ENOMEM);
a8237fc4	59	ret = cio_validate_subchannel (sch, schid);
1da177e4 LT	60	if (ret < 0) {
	61	kfree(sch);
	62	return ERR_PTR(ret);
	63	}
1da177e4 LT	64
	65	if (sch->st != SUBCHANNEL_TYPE_IO) {
	66	/* For now we ignore all non-io subchannels. */
	67	kfree(sch);
	68	return ERR_PTR(-EINVAL);
	69	}
	70
	71	/*
	72	* Set intparm to subchannel address.
	73	* This is fine even on 64bit since the subchannel is always located
	74	* under 2G.
	75	*/
	76	sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
	77	ret = cio_modify(sch);
	78	if (ret) {
	79	kfree(sch);
	80	return ERR_PTR(ret);
	81	}
	82	return sch;
	83	}
	84
	85	static void
	86	css_free_subchannel(struct subchannel *sch)
	87	{
	88	if (sch) {
	89	/* Reset intparm to zeroes. */
	90	sch->schib.pmcw.intparm = 0;
	91	cio_modify(sch);
	92	kfree(sch);
	93	}
	94
	95	}
	96
	97	static void
	98	css_subchannel_release(struct device *dev)
	99	{
	100	struct subchannel *sch;
	101
	102	sch = to_subchannel(dev);
a8237fc4	103	if (!cio_is_console(sch->schid))
1da177e4 LT	104	kfree(sch);
	105	}
	106
	107	extern int css_get_ssd_info(struct subchannel *sch);
	108
	109	static int
	110	css_register_subchannel(struct subchannel *sch)
	111	{
	112	int ret;
	113
	114	/* Initialize the subchannel structure */
a28c6944	115	sch->dev.parent = &css[0]->device;
1da177e4 LT	116	sch->dev.bus = &css_bus_type;
	117	sch->dev.release = &css_subchannel_release;
	118
	119	/* make it known to the system */
	120	ret = device_register(&sch->dev);
	121	if (ret)
	122	printk (KERN_WARNING "%s: could not register %s\n",
	123	__func__, sch->dev.bus_id);
	124	else
	125	css_get_ssd_info(sch);
	126	return ret;
	127	}
	128
	129	int
a8237fc4	130	css_probe_device(struct subchannel_id schid)
1da177e4 LT	131	{
	132	int ret;
	133	struct subchannel *sch;
	134
a8237fc4	135	sch = css_alloc_subchannel(schid);
1da177e4 LT	136	if (IS_ERR(sch))
	137	return PTR_ERR(sch);
	138	ret = css_register_subchannel(sch);
	139	if (ret)
	140	css_free_subchannel(sch);
	141	return ret;
	142	}
	143
b0744bd2 CH	144	static int
	145	check_subchannel(struct device * dev, void * data)
	146	{
	147	struct subchannel *sch;
a8237fc4	148	struct subchannel_id *schid = data;
b0744bd2 CH	149
b0744bd2 CH	150	sch = to_subchannel(dev);
a8237fc4	151	return schid_equal(&sch->schid, schid);
b0744bd2 CH	152	}
b0744bd2 CH	153
1da177e4	154	struct subchannel *
a8237fc4	155	get_subchannel_by_schid(struct subchannel_id schid)
1da177e4	156	{
1da177e4 LT	157	struct device *dev;
1da177e4 LT	158
b0744bd2	159	dev = bus_find_device(&css_bus_type, NULL,
a8237fc4	160	(void *)&schid, check_subchannel);
1da177e4	161
b0744bd2	162	return dev ? to_subchannel(dev) : NULL;
1da177e4 LT	163	}
1da177e4 LT	164
b0744bd2	165
1da177e4	166	static inline int
a8237fc4	167	css_get_subchannel_status(struct subchannel *sch, struct subchannel_id schid)
1da177e4 LT	168	{
	169	struct schib schib;
	170	int cc;
	171
	172	cc = stsch(schid, &schib);
	173	if (cc)
	174	return CIO_GONE;
	175	if (!schib.pmcw.dnv)
	176	return CIO_GONE;
	177	if (sch && sch->schib.pmcw.dnv &&
	178	(schib.pmcw.dev != sch->schib.pmcw.dev))
	179	return CIO_REVALIDATE;
	180	if (sch && !sch->lpm)
	181	return CIO_NO_PATH;
	182	return CIO_OPER;
	183	}
	184
	185	static int
a8237fc4	186	css_evaluate_subchannel(struct subchannel_id schid, int slow)
1da177e4 LT	187	{
	188	int event, ret, disc;
	189	struct subchannel *sch;
	190	unsigned long flags;
	191
a8237fc4	192	sch = get_subchannel_by_schid(schid);
1da177e4 LT	193	disc = sch ? device_is_disconnected(sch) : 0;
	194	if (disc && slow) {
	195	if (sch)
	196	put_device(&sch->dev);
	197	return 0; /* Already processed. */
	198	}
	199	/*
	200	* We've got a machine check, so running I/O won't get an interrupt.
	201	* Kill any pending timers.
	202	*/
	203	if (sch)
	204	device_kill_pending_timer(sch);
	205	if (!disc && !slow) {
	206	if (sch)
	207	put_device(&sch->dev);
	208	return -EAGAIN; /* Will be done on the slow path. */
	209	}
a8237fc4	210	event = css_get_subchannel_status(sch, schid);
fb6958a5 CH	211	CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
fb6958a5 CH	212	schid.ssid, schid.sch_no, event,
a8237fc4	213	sch?(disc?"disconnected":"normal"):"unknown",
1da177e4 LT	214	slow?"slow":"fast");
	215	switch (event) {
	216	case CIO_NO_PATH:
	217	case CIO_GONE:
	218	if (!sch) {
	219	/* Never used this subchannel. Ignore. */
	220	ret = 0;
	221	break;
	222	}
	223	if (disc && (event == CIO_NO_PATH)) {
	224	/*
	225	* Uargh, hack again. Because we don't get a machine
	226	* check on configure on, our path bookkeeping can
	227	* be out of date here (it's fine while we only do
	228	* logical varying or get chsc machine checks). We
	229	* need to force reprobing or we might miss devices
	230	* coming operational again. It won't do harm in real
	231	* no path situations.
	232	*/
	233	spin_lock_irqsave(&sch->lock, flags);
	234	device_trigger_reprobe(sch);
	235	spin_unlock_irqrestore(&sch->lock, flags);
	236	ret = 0;
	237	break;
	238	}
	239	if (sch->driver && sch->driver->notify &&
	240	sch->driver->notify(&sch->dev, event)) {
	241	cio_disable_subchannel(sch);
	242	device_set_disconnected(sch);
	243	ret = 0;
	244	break;
	245	}
	246	/*
	247	* Unregister subchannel.
	248	* The device will be killed automatically.
	249	*/
	250	cio_disable_subchannel(sch);
	251	device_unregister(&sch->dev);
	252	/* Reset intparm to zeroes. */
	253	sch->schib.pmcw.intparm = 0;
	254	cio_modify(sch);
	255	put_device(&sch->dev);
	256	ret = 0;
	257	break;
	258	case CIO_REVALIDATE:
	259	/*
	260	* Revalidation machine check. Sick.
	261	* We don't notify the driver since we have to throw the device
	262	* away in any case.
	263	*/
	264	if (!disc) {
	265	device_unregister(&sch->dev);
	266	/* Reset intparm to zeroes. */
	267	sch->schib.pmcw.intparm = 0;
	268	cio_modify(sch);
	269	put_device(&sch->dev);
a8237fc4	270	ret = css_probe_device(schid);
1da177e4 LT	271	} else {
	272	/*
	273	* We can't immediately deregister the disconnected
	274	* device since it might block.
	275	*/
	276	spin_lock_irqsave(&sch->lock, flags);
	277	device_trigger_reprobe(sch);
	278	spin_unlock_irqrestore(&sch->lock, flags);
	279	ret = 0;
	280	}
	281	break;
	282	case CIO_OPER:
	283	if (disc) {
	284	spin_lock_irqsave(&sch->lock, flags);
	285	/* Get device operational again. */
	286	device_trigger_reprobe(sch);
	287	spin_unlock_irqrestore(&sch->lock, flags);
	288	}
a8237fc4	289	ret = sch ? 0 : css_probe_device(schid);
1da177e4 LT	290	break;
	291	default:
	292	BUG();
	293	ret = 0;
	294	}
	295	return ret;
	296	}
	297
f97a56fb CH	298	static int
f97a56fb CH	299	css_rescan_devices(struct subchannel_id schid, void *data)
1da177e4	300	{
f97a56fb	301	return css_evaluate_subchannel(schid, 1);
1da177e4 LT	302	}
	303
	304	struct slow_subchannel {
	305	struct list_head slow_list;
a8237fc4	306	struct subchannel_id schid;
1da177e4 LT	307	};
	308
	309	static LIST_HEAD(slow_subchannels_head);
	310	static DEFINE_SPINLOCK(slow_subchannel_lock);
	311
	312	static void
	313	css_trigger_slow_path(void)
	314	{
	315	CIO_TRACE_EVENT(4, "slowpath");
	316
	317	if (need_rescan) {
	318	need_rescan = 0;
f97a56fb	319	for_each_subchannel(css_rescan_devices, NULL);
1da177e4 LT	320	return;
	321	}
	322
	323	spin_lock_irq(&slow_subchannel_lock);
	324	while (!list_empty(&slow_subchannels_head)) {
	325	struct slow_subchannel *slow_sch =
	326	list_entry(slow_subchannels_head.next,
	327	struct slow_subchannel, slow_list);
	328
	329	list_del_init(slow_subchannels_head.next);
	330	spin_unlock_irq(&slow_subchannel_lock);
	331	css_evaluate_subchannel(slow_sch->schid, 1);
	332	spin_lock_irq(&slow_subchannel_lock);
	333	kfree(slow_sch);
	334	}
	335	spin_unlock_irq(&slow_subchannel_lock);
	336	}
	337
	338	typedef void (workfunc)(void );
	339	DECLARE_WORK(slow_path_work, (workfunc)css_trigger_slow_path, NULL);
	340	struct workqueue_struct *slow_path_wq;
	341
	342	/*
	343	* Rescan for new devices. FIXME: This is slow.
	344	* This function is called when we have lost CRWs due to overflows and we have
	345	* to do subchannel housekeeping.
	346	*/
	347	void
	348	css_reiterate_subchannels(void)
	349	{
	350	css_clear_subchannel_slow_list();
	351	need_rescan = 1;
	352	}
	353
	354	/*
	355	* Called from the machine check handler for subchannel report words.
	356	*/
	357	int
fb6958a5	358	css_process_crw(int rsid1, int rsid2)
1da177e4 LT	359	{
1da177e4 LT	360	int ret;
a8237fc4	361	struct subchannel_id mchk_schid;
1da177e4	362
fb6958a5 CH	363	CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
fb6958a5 CH	364	rsid1, rsid2);
1da177e4 LT	365
	366	if (need_rescan)
	367	/* We need to iterate all subchannels anyway. */
	368	return -EAGAIN;
a8237fc4 CH	369
a8237fc4 CH	370	init_subchannel_id(&mchk_schid);
fb6958a5 CH	371	mchk_schid.sch_no = rsid1;
	372	if (rsid2 != 0)
	373	mchk_schid.ssid = (rsid2 >> 8) & 3;
	374
1da177e4 LT	375	/*
	376	* Since we are always presented with IPI in the CRW, we have to
	377	* use stsch() to find out if the subchannel in question has come
	378	* or gone.
	379	*/
a8237fc4	380	ret = css_evaluate_subchannel(mchk_schid, 0);
1da177e4	381	if (ret == -EAGAIN) {
a8237fc4	382	if (css_enqueue_subchannel_slow(mchk_schid)) {
1da177e4 LT	383	css_clear_subchannel_slow_list();
	384	need_rescan = 1;
	385	}
	386	}
	387	return ret;
	388	}
	389
f97a56fb CH	390	static int __init
	391	__init_channel_subsystem(struct subchannel_id schid, void *data)
	392	{
	393	struct subchannel *sch;
	394	int ret;
	395
	396	if (cio_is_console(schid))
	397	sch = cio_get_console_subchannel();
	398	else {
	399	sch = css_alloc_subchannel(schid);
	400	if (IS_ERR(sch))
	401	ret = PTR_ERR(sch);
	402	else
	403	ret = 0;
	404	switch (ret) {
	405	case 0:
	406	break;
	407	case -ENOMEM:
	408	panic("Out of memory in init_channel_subsystem\n");
	409	/* -ENXIO: no more subchannels. */
	410	case -ENXIO:
	411	return ret;
	412	default:
	413	return 0;
	414	}
	415	}
	416	/*
	417	* We register ALL valid subchannels in ioinfo, even those
	418	* that have been present before init_channel_subsystem.
	419	* These subchannels can't have been registered yet (kmalloc
	420	* not working) so we do it now. This is true e.g. for the
	421	* console subchannel.
	422	*/
	423	css_register_subchannel(sch);
	424	return 0;
	425	}
	426
1da177e4	427	static void __init
a28c6944	428	css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
1da177e4	429	{
a28c6944 CH	430	if (css_characteristics_avail && css_general_characteristics.mcss) {
	431	css->global_pgid.pgid_high.ext_cssid.version = 0x80;
	432	css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
	433	} else {
1da177e4	434	#ifdef CONFIG_SMP
a28c6944	435	css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
1da177e4	436	#else
a28c6944	437	css->global_pgid.pgid_high.cpu_addr = 0;
1da177e4 LT	438	#endif
1da177e4 LT	439	}
a28c6944 CH	440	css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
	441	css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
	442	css->global_pgid.tod_high = tod_high;
	443
	444	}
	445
3b793060 CH	446	static void
	447	channel_subsystem_release(struct device *dev)
	448	{
	449	struct channel_subsystem *css;
	450
	451	css = to_css(dev);
	452	kfree(css);
	453	}
	454
a28c6944 CH	455	static inline void __init
	456	setup_css(int nr)
	457	{
	458	u32 tod_high;
	459
	460	memset(css[nr], 0, sizeof(struct channel_subsystem));
	461	css[nr]->valid = 1;
	462	css[nr]->cssid = nr;
	463	sprintf(css[nr]->device.bus_id, "css%x", nr);
3b793060	464	css[nr]->device.release = channel_subsystem_release;
a28c6944 CH	465	tod_high = (u32) (get_clock() >> 32);
a28c6944 CH	466	css_generate_pgid(css[nr], tod_high);
1da177e4 LT	467	}
	468
	469	/*
	470	* Now that the driver core is running, we can setup our channel subsystem.
	471	* The struct subchannel's are created during probing (except for the
	472	* static console subchannel).
	473	*/
	474	static int __init
	475	init_channel_subsystem (void)
	476	{
a28c6944	477	int ret, i;
1da177e4 LT	478
	479	if (chsc_determine_css_characteristics() == 0)
	480	css_characteristics_avail = 1;
	481
1da177e4 LT	482	if ((ret = bus_register(&css_bus_type)))
1da177e4 LT	483	goto out;
1da177e4	484
fb6958a5 CH	485	/* Try to enable MSS. */
	486	ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
	487	switch (ret) {
	488	case 0: /* Success. */
	489	max_ssid = __MAX_SSID;
	490	break;
	491	case -ENOMEM:
	492	goto out_bus;
	493	default:
	494	max_ssid = 0;
	495	}
a28c6944 CH	496	/* Setup css structure. */
	497	for (i = 0; i <= __MAX_CSSID; i++) {
	498	css[i] = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
	499	if (!css[i]) {
	500	ret = -ENOMEM;
fb6958a5	501	goto out_unregister;
a28c6944 CH	502	}
	503	setup_css(i);
	504	ret = device_register(&css[i]->device);
	505	if (ret)
	506	goto out_free;
	507	}
1da177e4 LT	508	css_init_done = 1;
	509
	510	ctl_set_bit(6, 28);
	511
f97a56fb	512	for_each_subchannel(__init_channel_subsystem, NULL);
1da177e4	513	return 0;
a28c6944 CH	514	out_free:
a28c6944 CH	515	kfree(css[i]);
fb6958a5	516	out_unregister:
a28c6944 CH	517	while (i > 0) {
	518	i--;
	519	device_unregister(&css[i]->device);
	520	}
fb6958a5	521	out_bus:
1da177e4 LT	522	bus_unregister(&css_bus_type);
	523	out:
	524	return ret;
	525	}
	526
	527	/*
	528	* find a driver for a subchannel. They identify by the subchannel
	529	* type with the exception that the console subchannel driver has its own
	530	* subchannel type although the device is an i/o subchannel
	531	*/
	532	static int
	533	css_bus_match (struct device dev, struct device_driver drv)
	534	{
	535	struct subchannel *sch = container_of (dev, struct subchannel, dev);
	536	struct css_driver *driver = container_of (drv, struct css_driver, drv);
	537
	538	if (sch->st == driver->subchannel_type)
	539	return 1;
	540
	541	return 0;
	542	}
	543
8bbace7e CH	544	static int
	545	css_probe (struct device *dev)
	546	{
	547	struct subchannel *sch;
	548
	549	sch = to_subchannel(dev);
	550	sch->driver = container_of (dev->driver, struct css_driver, drv);
	551	return (sch->driver->probe ? sch->driver->probe(sch) : 0);
	552	}
	553
	554	static int
	555	css_remove (struct device *dev)
	556	{
	557	struct subchannel *sch;
	558
	559	sch = to_subchannel(dev);
	560	return (sch->driver->remove ? sch->driver->remove(sch) : 0);
	561	}
	562
	563	static void
	564	css_shutdown (struct device *dev)
	565	{
	566	struct subchannel *sch;
	567
	568	sch = to_subchannel(dev);
	569	if (sch->driver->shutdown)
	570	sch->driver->shutdown(sch);
	571	}
	572
1da177e4	573	struct bus_type css_bus_type = {
8bbace7e CH	574	.name = "css",
	575	.match = css_bus_match,
	576	.probe = css_probe,
	577	.remove = css_remove,
	578	.shutdown = css_shutdown,
1da177e4 LT	579	};
	580
	581	subsys_initcall(init_channel_subsystem);
	582
1da177e4	583	int
a8237fc4	584	css_enqueue_subchannel_slow(struct subchannel_id schid)
1da177e4 LT	585	{
	586	struct slow_subchannel *new_slow_sch;
	587	unsigned long flags;
	588
	589	new_slow_sch = kmalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
	590	if (!new_slow_sch)
	591	return -ENOMEM;
	592	memset(new_slow_sch, 0, sizeof(struct slow_subchannel));
	593	new_slow_sch->schid = schid;
	594	spin_lock_irqsave(&slow_subchannel_lock, flags);
	595	list_add_tail(&new_slow_sch->slow_list, &slow_subchannels_head);
	596	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
	597	return 0;
	598	}
	599
	600	void
	601	css_clear_subchannel_slow_list(void)
	602	{
	603	unsigned long flags;
	604
	605	spin_lock_irqsave(&slow_subchannel_lock, flags);
	606	while (!list_empty(&slow_subchannels_head)) {
	607	struct slow_subchannel *slow_sch =
	608	list_entry(slow_subchannels_head.next,
	609	struct slow_subchannel, slow_list);
	610
	611	list_del_init(slow_subchannels_head.next);
	612	kfree(slow_sch);
	613	}
	614	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
	615	}
	616
	617
	618
	619	int
	620	css_slow_subchannels_exist(void)
	621	{
	622	return (!list_empty(&slow_subchannels_head));
	623	}
	624
	625	MODULE_LICENSE("GPL");
	626	EXPORT_SYMBOL(css_bus_type);
1da177e4	627	EXPORT_SYMBOL_GPL(css_characteristics_avail);