css.c 16.6 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1
2
3
4
5
6
7
/*
 *  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)
8
 *		 Cornelia Huck (cornelia.huck@de.ibm.com)
Linus Torvalds's avatar
Linus Torvalds committed
9
10
11
12
13
14
15
16
17
18
19
20
21
 */
#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"
22
#include "device.h"
Linus Torvalds's avatar
Linus Torvalds committed
23
24
25

int need_rescan = 0;
int css_init_done = 0;
26
static int need_reprobe = 0;
27
static int max_ssid = 0;
Linus Torvalds's avatar
Linus Torvalds committed
28

29
struct channel_subsystem *css[__MAX_CSSID + 1];
Linus Torvalds's avatar
Linus Torvalds committed
30

31
int css_characteristics_avail = 0;
Linus Torvalds's avatar
Linus Torvalds committed
32

33
34
35
36
37
38
39
40
41
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 {
42
43
44
45
46
47
48
		do {
			ret = fn(schid, data);
			if (ret)
				break;
		} while (schid.sch_no++ < __MAX_SUBCHANNEL);
		schid.sch_no = 0;
	} while (schid.ssid++ < max_ssid);
49
50
51
	return ret;
}

Linus Torvalds's avatar
Linus Torvalds committed
52
static struct subchannel *
53
css_alloc_subchannel(struct subchannel_id schid)
Linus Torvalds's avatar
Linus Torvalds committed
54
55
56
57
58
59
60
{
	struct subchannel *sch;
	int ret;

	sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
	if (sch == NULL)
		return ERR_PTR(-ENOMEM);
61
	ret = cio_validate_subchannel (sch, schid);
Linus Torvalds's avatar
Linus Torvalds committed
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
	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);
105
	if (!cio_is_console(sch->schid))
Linus Torvalds's avatar
Linus Torvalds committed
106
107
108
109
110
		kfree(sch);
}

extern int css_get_ssd_info(struct subchannel *sch);

111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128

int css_sch_device_register(struct subchannel *sch)
{
	int ret;

	mutex_lock(&sch->reg_mutex);
	ret = device_register(&sch->dev);
	mutex_unlock(&sch->reg_mutex);
	return ret;
}

void css_sch_device_unregister(struct subchannel *sch)
{
	mutex_lock(&sch->reg_mutex);
	device_unregister(&sch->dev);
	mutex_unlock(&sch->reg_mutex);
}

Linus Torvalds's avatar
Linus Torvalds committed
129
130
131
132
133
134
static int
css_register_subchannel(struct subchannel *sch)
{
	int ret;

	/* Initialize the subchannel structure */
135
	sch->dev.parent = &css[0]->device;
Linus Torvalds's avatar
Linus Torvalds committed
136
137
138
139
	sch->dev.bus = &css_bus_type;
	sch->dev.release = &css_subchannel_release;
	
	/* make it known to the system */
140
	ret = css_sch_device_register(sch);
Linus Torvalds's avatar
Linus Torvalds committed
141
142
143
144
145
146
147
148
149
	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
150
css_probe_device(struct subchannel_id schid)
Linus Torvalds's avatar
Linus Torvalds committed
151
152
153
154
{
	int ret;
	struct subchannel *sch;

155
	sch = css_alloc_subchannel(schid);
Linus Torvalds's avatar
Linus Torvalds committed
156
157
158
159
160
161
162
163
	if (IS_ERR(sch))
		return PTR_ERR(sch);
	ret = css_register_subchannel(sch);
	if (ret)
		css_free_subchannel(sch);
	return ret;
}

164
165
166
167
static int
check_subchannel(struct device * dev, void * data)
{
	struct subchannel *sch;
168
	struct subchannel_id *schid = data;
169
170

	sch = to_subchannel(dev);
171
	return schid_equal(&sch->schid, schid);
172
173
}

Linus Torvalds's avatar
Linus Torvalds committed
174
struct subchannel *
175
get_subchannel_by_schid(struct subchannel_id schid)
Linus Torvalds's avatar
Linus Torvalds committed
176
177
178
{
	struct device *dev;

179
	dev = bus_find_device(&css_bus_type, NULL,
180
			      &schid, check_subchannel);
Linus Torvalds's avatar
Linus Torvalds committed
181

182
	return dev ? to_subchannel(dev) : NULL;
Linus Torvalds's avatar
Linus Torvalds committed
183
184
}

185
static inline int css_get_subchannel_status(struct subchannel *sch)
Linus Torvalds's avatar
Linus Torvalds committed
186
187
188
{
	struct schib schib;

189
	if (stsch(sch->schid, &schib) || !schib.pmcw.dnv)
Linus Torvalds's avatar
Linus Torvalds committed
190
		return CIO_GONE;
191
	if (sch->schib.pmcw.dnv && (schib.pmcw.dev != sch->schib.pmcw.dev))
Linus Torvalds's avatar
Linus Torvalds committed
192
		return CIO_REVALIDATE;
193
	if (!sch->lpm)
Linus Torvalds's avatar
Linus Torvalds committed
194
195
196
		return CIO_NO_PATH;
	return CIO_OPER;
}
197
198

static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
Linus Torvalds's avatar
Linus Torvalds committed
199
200
201
{
	int event, ret, disc;
	unsigned long flags;
202
	enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE } action;
Linus Torvalds's avatar
Linus Torvalds committed
203

204
205
	spin_lock_irqsave(&sch->lock, flags);
	disc = device_is_disconnected(sch);
Linus Torvalds's avatar
Linus Torvalds committed
206
	if (disc && slow) {
207
208
209
		/* Disconnected devices are evaluated directly only.*/
		spin_unlock_irqrestore(&sch->lock, flags);
		return 0;
Linus Torvalds's avatar
Linus Torvalds committed
210
	}
211
212
	/* No interrupt after machine check - kill pending timers. */
	device_kill_pending_timer(sch);
Linus Torvalds's avatar
Linus Torvalds committed
213
	if (!disc && !slow) {
214
215
216
		/* Non-disconnected devices are evaluated on the slow path. */
		spin_unlock_irqrestore(&sch->lock, flags);
		return -EAGAIN;
Linus Torvalds's avatar
Linus Torvalds committed
217
	}
218
	event = css_get_subchannel_status(sch);
219
	CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
220
221
222
223
224
		      sch->schid.ssid, sch->schid.sch_no, event,
		      disc ? "disconnected" : "normal",
		      slow ? "slow" : "fast");
	/* Analyze subchannel status. */
	action = NONE;
Linus Torvalds's avatar
Linus Torvalds committed
225
226
	switch (event) {
	case CIO_NO_PATH:
227
228
229
		if (disc) {
			/* Check if paths have become available. */
			action = REPROBE;
Linus Torvalds's avatar
Linus Torvalds committed
230
231
			break;
		}
232
233
234
235
236
237
238
239
		/* fall through */
	case CIO_GONE:
		/* Prevent unwanted effects when opening lock. */
		cio_disable_subchannel(sch);
		device_set_disconnected(sch);
		/* Ask driver what to do with device. */
		action = UNREGISTER;
		if (sch->driver && sch->driver->notify) {
Linus Torvalds's avatar
Linus Torvalds committed
240
			spin_unlock_irqrestore(&sch->lock, flags);
241
242
243
244
			ret = sch->driver->notify(&sch->dev, event);
			spin_lock_irqsave(&sch->lock, flags);
			if (ret)
				action = NONE;
Linus Torvalds's avatar
Linus Torvalds committed
245
246
247
		}
		break;
	case CIO_REVALIDATE:
248
249
250
251
252
253
		/* Device will be removed, so no notify necessary. */
		if (disc)
			/* Reprobe because immediate unregister might block. */
			action = REPROBE;
		else
			action = UNREGISTER_PROBE;
Linus Torvalds's avatar
Linus Torvalds committed
254
255
		break;
	case CIO_OPER:
256
		if (disc)
Linus Torvalds's avatar
Linus Torvalds committed
257
			/* Get device operational again. */
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
			action = REPROBE;
		break;
	}
	/* Perform action. */
	ret = 0;
	switch (action) {
	case UNREGISTER:
	case UNREGISTER_PROBE:
		/* Unregister device (will use subchannel lock). */
		spin_unlock_irqrestore(&sch->lock, flags);
		css_sch_device_unregister(sch);
		spin_lock_irqsave(&sch->lock, flags);

		/* Reset intparm to zeroes. */
		sch->schib.pmcw.intparm = 0;
		cio_modify(sch);
		break;
	case REPROBE:
		device_trigger_reprobe(sch);
Linus Torvalds's avatar
Linus Torvalds committed
277
278
		break;
	default:
279
280
281
		break;
	}
	spin_unlock_irqrestore(&sch->lock, flags);
282
283
284
	/* Probe if necessary. */
	if (action == UNREGISTER_PROBE)
		ret = css_probe_device(sch->schid);
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299

	return ret;
}

static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
{
	struct schib schib;

	if (!slow) {
		/* Will be done on the slow path. */
		return -EAGAIN;
	}
	if (stsch(schid, &schib) || !schib.pmcw.dnv) {
		/* Unusable - ignore. */
		return 0;
Linus Torvalds's avatar
Linus Torvalds committed
300
	}
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
	CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, unknown, "
			 "slow path.\n", schid.ssid, schid.sch_no, CIO_OPER);

	return css_probe_device(schid);
}

static int css_evaluate_subchannel(struct subchannel_id schid, int slow)
{
	struct subchannel *sch;
	int ret;

	sch = get_subchannel_by_schid(schid);
	if (sch) {
		ret = css_evaluate_known_subchannel(sch, slow);
		put_device(&sch->dev);
	} else
		ret = css_evaluate_new_subchannel(schid, slow);

Linus Torvalds's avatar
Linus Torvalds committed
319
320
321
	return ret;
}

322
323
static int
css_rescan_devices(struct subchannel_id schid, void *data)
Linus Torvalds's avatar
Linus Torvalds committed
324
{
325
	return css_evaluate_subchannel(schid, 1);
Linus Torvalds's avatar
Linus Torvalds committed
326
327
328
329
}

struct slow_subchannel {
	struct list_head slow_list;
330
	struct subchannel_id schid;
Linus Torvalds's avatar
Linus Torvalds committed
331
332
333
334
335
336
};

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

static void
337
css_trigger_slow_path(struct work_struct *unused)
Linus Torvalds's avatar
Linus Torvalds committed
338
339
340
341
342
{
	CIO_TRACE_EVENT(4, "slowpath");

	if (need_rescan) {
		need_rescan = 0;
343
		for_each_subchannel(css_rescan_devices, NULL);
Linus Torvalds's avatar
Linus Torvalds committed
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
		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);
}

362
DECLARE_WORK(slow_path_work, css_trigger_slow_path);
Linus Torvalds's avatar
Linus Torvalds committed
363
364
struct workqueue_struct *slow_path_wq;

365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
/* Reprobe subchannel if unregistered. */
static int reprobe_subchannel(struct subchannel_id schid, void *data)
{
	struct subchannel *sch;
	int ret;

	CIO_DEBUG(KERN_INFO, 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:
		/* These should abort looping */
		break;
	default:
		ret = 0;
	}

	return ret;
}

/* Work function used to reprobe all unregistered subchannels. */
399
static void reprobe_all(struct work_struct *unused)
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
{
	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);
}

415
DECLARE_WORK(css_reprobe_work, reprobe_all);
416
417
418
419
420
421
422
423
424
425

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

EXPORT_SYMBOL_GPL(css_schedule_reprobe);

Linus Torvalds's avatar
Linus Torvalds committed
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
/*
 * 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
442
css_process_crw(int rsid1, int rsid2)
Linus Torvalds's avatar
Linus Torvalds committed
443
444
{
	int ret;
445
	struct subchannel_id mchk_schid;
Linus Torvalds's avatar
Linus Torvalds committed
446

447
448
	CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
		      rsid1, rsid2);
Linus Torvalds's avatar
Linus Torvalds committed
449
450
451
452

	if (need_rescan)
		/* We need to iterate all subchannels anyway. */
		return -EAGAIN;
453
454

	init_subchannel_id(&mchk_schid);
455
456
457
458
	mchk_schid.sch_no = rsid1;
	if (rsid2 != 0)
		mchk_schid.ssid = (rsid2 >> 8) & 3;

Linus Torvalds's avatar
Linus Torvalds committed
459
460
461
462
463
	/* 
	 * 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.
	 */
464
	ret = css_evaluate_subchannel(mchk_schid, 0);
Linus Torvalds's avatar
Linus Torvalds committed
465
	if (ret == -EAGAIN) {
466
		if (css_enqueue_subchannel_slow(mchk_schid)) {
Linus Torvalds's avatar
Linus Torvalds committed
467
468
469
470
471
472
473
			css_clear_subchannel_slow_list();
			need_rescan = 1;
		}
	}
	return ret;
}

474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
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;
496
497
498
		/* -EIO: this subchannel set not supported. */
		case -EIO:
			return ret;
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
		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;
}

Linus Torvalds's avatar
Linus Torvalds committed
514
static void __init
515
css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
Linus Torvalds's avatar
Linus Torvalds committed
516
{
517
518
519
520
	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 {
Linus Torvalds's avatar
Linus Torvalds committed
521
#ifdef CONFIG_SMP
522
		css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
Linus Torvalds's avatar
Linus Torvalds committed
523
#else
524
		css->global_pgid.pgid_high.cpu_addr = 0;
Linus Torvalds's avatar
Linus Torvalds committed
525
526
#endif
	}
527
528
529
530
531
532
	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;

}

533
534
535
536
537
538
static void
channel_subsystem_release(struct device *dev)
{
	struct channel_subsystem *css;

	css = to_css(dev);
539
	mutex_destroy(&css->mutex);
540
541
542
	kfree(css);
}

543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
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);

576
577
578
579
580
581
static inline void __init
setup_css(int nr)
{
	u32 tod_high;

	memset(css[nr], 0, sizeof(struct channel_subsystem));
582
	mutex_init(&css[nr]->mutex);
583
584
585
	css[nr]->valid = 1;
	css[nr]->cssid = nr;
	sprintf(css[nr]->device.bus_id, "css%x", nr);
586
	css[nr]->device.release = channel_subsystem_release;
587
588
	tod_high = (u32) (get_clock() >> 32);
	css_generate_pgid(css[nr], tod_high);
Linus Torvalds's avatar
Linus Torvalds committed
589
590
591
592
593
594
595
596
597
598
}

/*
 * 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)
{
599
	int ret, i;
Linus Torvalds's avatar
Linus Torvalds committed
600
601
602
603
604
605
606

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

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

607
608
609
610
611
612
613
614
615
616
617
	/* 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;
	}
618
619
620
621
622
	/* Setup css structure. */
	for (i = 0; i <= __MAX_CSSID; i++) {
		css[i] = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
		if (!css[i]) {
			ret = -ENOMEM;
623
			goto out_unregister;
624
625
626
627
628
		}
		setup_css(i);
		ret = device_register(&css[i]->device);
		if (ret)
			goto out_free;
629
630
631
632
633
634
635
		if (css_characteristics_avail &&
		    css_chsc_characteristics.secm) {
			ret = device_create_file(&css[i]->device,
						 &dev_attr_cm_enable);
			if (ret)
				goto out_device;
		}
636
	}
Linus Torvalds's avatar
Linus Torvalds committed
637
638
639
640
	css_init_done = 1;

	ctl_set_bit(6, 28);

641
	for_each_subchannel(__init_channel_subsystem, NULL);
Linus Torvalds's avatar
Linus Torvalds committed
642
	return 0;
643
644
out_device:
	device_unregister(&css[i]->device);
645
646
out_free:
	kfree(css[i]);
647
out_unregister:
648
649
	while (i > 0) {
		i--;
650
651
652
		if (css_characteristics_avail && css_chsc_characteristics.secm)
			device_remove_file(&css[i]->device,
					   &dev_attr_cm_enable);
653
654
		device_unregister(&css[i]->device);
	}
655
out_bus:
Linus Torvalds's avatar
Linus Torvalds committed
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
	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;
}

678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
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);
}

Linus Torvalds's avatar
Linus Torvalds committed
707
struct bus_type css_bus_type = {
708
709
710
711
712
	.name     = "css",
	.match    = css_bus_match,
	.probe    = css_probe,
	.remove   = css_remove,
	.shutdown = css_shutdown,
Linus Torvalds's avatar
Linus Torvalds committed
713
714
715
716
717
};

subsys_initcall(init_channel_subsystem);

int
718
css_enqueue_subchannel_slow(struct subchannel_id schid)
Linus Torvalds's avatar
Linus Torvalds committed
719
720
721
722
{
	struct slow_subchannel *new_slow_sch;
	unsigned long flags;

723
	new_slow_sch = kzalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
Linus Torvalds's avatar
Linus Torvalds committed
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
	if (!new_slow_sch)
		return -ENOMEM;
	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);