summaryrefslogblamecommitdiffstats
path: root/drivers/s390/cio/cmf.c
blob: b978f7fe8327546aca8a195f82183a1e87601af4 (plain) (tree)
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
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
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
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
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
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
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644































                                                                       

                                                 



                       
                      




























































































































































































































































































































































































































































































































































































































                                                                                
                                  


























































































































































                                                                                
                                                                                          















                                                                
                                                                                      



























                                                                        
                                                                                               



                                                     
                                                                                                   





















































                                                                                  
                                                                                            



                                                                          
                                                                                                             



































































































































                                                                                     
/*
 * linux/drivers/s390/cio/cmf.c ($Revision: 1.16 $)
 *
 * Linux on zSeries Channel Measurement Facility support
 *
 * Copyright 2000,2003 IBM Corporation
 *
 * Author: Arnd Bergmann <arndb@de.ibm.com>
 *
 * original idea from Natarajan Krishnaswami <nkrishna@us.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/bootmem.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/timex.h>	/* get_clock() */

#include <asm/ccwdev.h>
#include <asm/cio.h>
#include <asm/cmb.h>
#include <asm/div64.h>

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

/* parameter to enable cmf during boot, possible uses are:
 *  "s390cmf" -- enable cmf and allocate 2 MB of ram so measuring can be
 *               used on any subchannel
 *  "s390cmf=<num>" -- enable cmf and allocate enough memory to measure
 *                     <num> subchannel, where <num> is an integer
 *                     between 1 and 65535, default is 1024
 */
#define ARGSTRING "s390cmf"

/* indices for READCMB */
enum cmb_index {
 /* basic and exended format: */
	cmb_ssch_rsch_count,
	cmb_sample_count,
	cmb_device_connect_time,
	cmb_function_pending_time,
	cmb_device_disconnect_time,
	cmb_control_unit_queuing_time,
	cmb_device_active_only_time,
 /* extended format only: */
	cmb_device_busy_time,
	cmb_initial_command_response_time,
};

/**
 * enum cmb_format - types of supported measurement block formats
 *
 * @CMF_BASIC:      traditional channel measurement blocks supported
 * 		    by all machines that we run on
 * @CMF_EXTENDED:   improved format that was introduced with the z990
 * 		    machine
 * @CMF_AUTODETECT: default: use extended format when running on a z990
 *                  or later machine, otherwise fall back to basic format
 **/
enum cmb_format {
	CMF_BASIC,
	CMF_EXTENDED,
	CMF_AUTODETECT = -1,
};
/**
 * format - actual format for all measurement blocks
 *
 * The format module parameter can be set to a value of 0 (zero)
 * or 1, indicating basic or extended format as described for
 * enum cmb_format.
 */
static int format = CMF_AUTODETECT;
module_param(format, bool, 0444);

/**
 * struct cmb_operations - functions to use depending on cmb_format
 *
 * all these functions operate on a struct cmf_device. There is only
 * one instance of struct cmb_operations because all cmf_device
 * objects are guaranteed to be of the same type.
 *
 * @alloc:	allocate memory for a channel measurement block,
 *		either with the help of a special pool or with kmalloc
 * @free:	free memory allocated with @alloc
 * @set:	enable or disable measurement
 * @readall:	read a measurement block in a common format
 * @reset:	clear the data in the associated measurement block and
 *		reset its time stamp
 */
struct cmb_operations {
	int (*alloc)  (struct ccw_device*);
	void(*free)   (struct ccw_device*);
	int (*set)    (struct ccw_device*, u32);
	u64 (*read)   (struct ccw_device*, int);
	int (*readall)(struct ccw_device*, struct cmbdata *);
	void (*reset) (struct ccw_device*);

	struct attribute_group *attr_group;
};
static struct cmb_operations *cmbops;

/* our user interface is designed in terms of nanoseconds,
 * while the hardware measures total times in its own
 * unit.*/
static inline u64 time_to_nsec(u32 value)
{
	return ((u64)value) * 128000ull;
}

/*
 * Users are usually interested in average times,
 * not accumulated time.
 * This also helps us with atomicity problems
 * when reading sinlge values.
 */
static inline u64 time_to_avg_nsec(u32 value, u32 count)
{
	u64 ret;

	/* no samples yet, avoid division by 0 */
	if (count == 0)
		return 0;

	/* value comes in units of 128 µsec */
	ret = time_to_nsec(value);
	do_div(ret, count);

	return ret;
}

/* activate or deactivate the channel monitor. When area is NULL,
 * the monitor is deactivated. The channel monitor needs to
 * be active in order to measure subchannels, which also need
 * to be enabled. */
static inline void
cmf_activate(void *area, unsigned int onoff)
{
	register void * __gpr2 asm("2");
	register long __gpr1 asm("1");

	__gpr2 = area;
	__gpr1 = onoff ? 2 : 0;
	/* activate channel measurement */
	asm("schm" : : "d" (__gpr2), "d" (__gpr1) );
}

static int
set_schib(struct ccw_device *cdev, u32 mme, int mbfc, unsigned long address)
{
	int ret;
	int retry;
	struct subchannel *sch;
	struct schib *schib;

	sch = to_subchannel(cdev->dev.parent);
	schib = &sch->schib;
	/* msch can silently fail, so do it again if necessary */
	for (retry = 0; retry < 3; retry++) {
		/* prepare schib */
		stsch(sch->irq, schib);
		schib->pmcw.mme  = mme;
		schib->pmcw.mbfc = mbfc;
		/* address can be either a block address or a block index */
		if (mbfc)
			schib->mba = address;
		else
			schib->pmcw.mbi = address;

		/* try to submit it */
		switch(ret = msch_err(sch->irq, schib)) {
			case 0:
				break;
			case 1:
			case 2: /* in I/O or status pending */
				ret = -EBUSY;
				break;
			case 3: /* subchannel is no longer valid */
				ret = -ENODEV;
				break;
			default: /* msch caught an exception */
				ret = -EINVAL;
				break;
		}
		stsch(sch->irq, schib); /* restore the schib */

		if (ret)
			break;

		/* check if it worked */
		if (schib->pmcw.mme  == mme &&
		    schib->pmcw.mbfc == mbfc &&
		    (mbfc ? (schib->mba == address)
			  : (schib->pmcw.mbi == address)))
			return 0;

		ret = -EINVAL;
	}

	return ret;
}

struct set_schib_struct {
	u32 mme;
	int mbfc;
	unsigned long address;
	wait_queue_head_t wait;
	int ret;
};

static int set_schib_wait(struct ccw_device *cdev, u32 mme,
				int mbfc, unsigned long address)
{
	struct set_schib_struct s = {
		.mme = mme,
		.mbfc = mbfc,
		.address = address,
		.wait = __WAIT_QUEUE_HEAD_INITIALIZER(s.wait),
	};

	spin_lock_irq(cdev->ccwlock);
	s.ret = set_schib(cdev, mme, mbfc, address);
	if (s.ret != -EBUSY) {
		goto out_nowait;
	}

	if (cdev->private->state != DEV_STATE_ONLINE) {
		s.ret = -EBUSY;
		/* if the device is not online, don't even try again */
		goto out_nowait;
	}
	cdev->private->state = DEV_STATE_CMFCHANGE;
	cdev->private->cmb_wait = &s;
	s.ret = 1;

	spin_unlock_irq(cdev->ccwlock);
	if (wait_event_interruptible(s.wait, s.ret != 1)) {
		spin_lock_irq(cdev->ccwlock);
		if (s.ret == 1) {
			s.ret = -ERESTARTSYS;
			cdev->private->cmb_wait = 0;
			if (cdev->private->state == DEV_STATE_CMFCHANGE)
				cdev->private->state = DEV_STATE_ONLINE;
		}
		spin_unlock_irq(cdev->ccwlock);
	}
	return s.ret;

out_nowait:
	spin_unlock_irq(cdev->ccwlock);
	return s.ret;
}

void retry_set_schib(struct ccw_device *cdev)
{
	struct set_schib_struct *s;

	s = cdev->private->cmb_wait;
	cdev->private->cmb_wait = 0;
	if (!s) {
		WARN_ON(1);
		return;
	}
	s->ret = set_schib(cdev, s->mme, s->mbfc, s->address);
	wake_up(&s->wait);
}

/**
 * struct cmb_area - container for global cmb data
 *
 * @mem:	pointer to CMBs (only in basic measurement mode)
 * @list:	contains a linked list of all subchannels
 * @lock:	protect concurrent access to @mem and @list
 */
struct cmb_area {
	struct cmb *mem;
	struct list_head list;
	int num_channels;
	spinlock_t lock;
};

static struct cmb_area cmb_area = {
	.lock = SPIN_LOCK_UNLOCKED,
	.list = LIST_HEAD_INIT(cmb_area.list),
	.num_channels  = 1024,
};


/* ****** old style CMB handling ********/

/** int maxchannels
 *
 * Basic channel measurement blocks are allocated in one contiguous
 * block of memory, which can not be moved as long as any channel
 * is active. Therefore, a maximum number of subchannels needs to
 * be defined somewhere. This is a module parameter, defaulting to
 * a resonable value of 1024, or 32 kb of memory.
 * Current kernels don't allow kmalloc with more than 128kb, so the
 * maximum is 4096
 */

module_param_named(maxchannels, cmb_area.num_channels, uint, 0444);

/**
 * struct cmb - basic channel measurement block
 *
 * cmb as used by the hardware the fields are described in z/Architecture
 * Principles of Operation, chapter 17.
 * The area to be a contiguous array and may not be reallocated or freed.
 * Only one cmb area can be present in the system.
 */
struct cmb {
	u16 ssch_rsch_count;
	u16 sample_count;
	u32 device_connect_time;
	u32 function_pending_time;
	u32 device_disconnect_time;
	u32 control_unit_queuing_time;
	u32 device_active_only_time;
	u32 reserved[2];
};

/* insert a single device into the cmb_area list
 * called with cmb_area.lock held from alloc_cmb
 */
static inline int
alloc_cmb_single (struct ccw_device *cdev)
{
	struct cmb *cmb;
	struct ccw_device_private *node;
	int ret;

	spin_lock_irq(cdev->ccwlock);
	if (!list_empty(&cdev->private->cmb_list)) {
		ret = -EBUSY;
		goto out;
	}

	/* find first unused cmb in cmb_area.mem.
	 * this is a little tricky: cmb_area.list
	 * remains sorted by ->cmb pointers */
	cmb = cmb_area.mem;
	list_for_each_entry(node, &cmb_area.list, cmb_list) {
		if ((struct cmb*)node->cmb > cmb)
			break;
		cmb++;
	}
	if (cmb - cmb_area.mem >= cmb_area.num_channels) {
		ret = -ENOMEM;
		goto out;
	}

	/* insert new cmb */
	list_add_tail(&cdev->private->cmb_list, &node->cmb_list);
	cdev->private->cmb = cmb;
	ret = 0;
out:
	spin_unlock_irq(cdev->ccwlock);
	return ret;
}

static int
alloc_cmb (struct ccw_device *cdev)
{
	int ret;
	struct cmb *mem;
	ssize_t size;

	spin_lock(&cmb_area.lock);

	if (!cmb_area.mem) {
		/* there is no user yet, so we need a new area */
		size = sizeof(struct cmb) * cmb_area.num_channels;
		WARN_ON(!list_empty(&cmb_area.list));

		spin_unlock(&cmb_area.lock);
		mem = (void*)__get_free_pages(GFP_KERNEL | GFP_DMA,
				 get_order(size));
		spin_lock(&cmb_area.lock);

		if (cmb_area.mem) {
			/* ok, another thread was faster */
			free_pages((unsigned long)mem, get_order(size));
		} else if (!mem) {
			/* no luck */
			ret = -ENOMEM;
			goto out;
		} else {
			/* everything ok */
			memset(mem, 0, size);
			cmb_area.mem = mem;
			cmf_activate(cmb_area.mem, 1);
		}
	}

	/* do the actual allocation */
	ret = alloc_cmb_single(cdev);
out:
	spin_unlock(&cmb_area.lock);

	return ret;
}

static void
free_cmb(struct ccw_device *cdev)
{
	struct ccw_device_private *priv;

	priv = cdev->private;

	spin_lock(&cmb_area.lock);
	spin_lock_irq(cdev->ccwlock);

	if (list_empty(&priv->cmb_list)) {
		/* already freed */
		goto out;
	}

	priv->cmb = NULL;
	list_del_init(&priv->cmb_list);

	if (list_empty(&cmb_area.list)) {
		ssize_t size;
		size = sizeof(struct cmb) * cmb_area.num_channels;
		cmf_activate(NULL, 0);
		free_pages((unsigned long)cmb_area.mem, get_order(size));
		cmb_area.mem = NULL;
	}
out:
	spin_unlock_irq(cdev->ccwlock);
	spin_unlock(&cmb_area.lock);
}

static int
set_cmb(struct ccw_device *cdev, u32 mme)
{
	u16 offset;

	if (!cdev->private->cmb)
		return -EINVAL;

	offset = mme ? (struct cmb *)cdev->private->cmb - cmb_area.mem : 0;

	return set_schib_wait(cdev, mme, 0, offset);
}

static u64
read_cmb (struct ccw_device *cdev, int index)
{
	/* yes, we have to put it on the stack
	 * because the cmb must only be accessed
	 * atomically, e.g. with mvc */
	struct cmb cmb;
	unsigned long flags;
	u32 val;

	spin_lock_irqsave(cdev->ccwlock, flags);
	if (!cdev->private->cmb) {
		spin_unlock_irqrestore(cdev->ccwlock, flags);
		return 0;
	}

	cmb = *(struct cmb*)cdev->private->cmb;
	spin_unlock_irqrestore(cdev->ccwlock, flags);

	switch (index) {
	case cmb_ssch_rsch_count:
		return cmb.ssch_rsch_count;
	case cmb_sample_count:
		return cmb.sample_count;
	case cmb_device_connect_time:
		val = cmb.device_connect_time;
		break;
	case cmb_function_pending_time:
		val = cmb.function_pending_time;
		break;
	case cmb_device_disconnect_time:
		val = cmb.device_disconnect_time;
		break;
	case cmb_control_unit_queuing_time:
		val = cmb.control_unit_queuing_time;
		break;
	case cmb_device_active_only_time:
		val = cmb.device_active_only_time;
		break;
	default:
		return 0;
	}
	return time_to_avg_nsec(val, cmb.sample_count);
}

static int
readall_cmb (struct ccw_device *cdev, struct cmbdata *data)
{
	/* yes, we have to put it on the stack
	 * because the cmb must only be accessed
	 * atomically, e.g. with mvc */
	struct cmb cmb;
	unsigned long flags;
	u64 time;

	spin_lock_irqsave(cdev->ccwlock, flags);
	if (!cdev->private->cmb) {
		spin_unlock_irqrestore(cdev->ccwlock, flags);
		return -ENODEV;
	}

	cmb = *(struct cmb*)cdev->private->cmb;
	time = get_clock() - cdev->private->cmb_start_time;
	spin_unlock_irqrestore(cdev->ccwlock, flags);

	memset(data, 0, sizeof(struct cmbdata));

	/* we only know values before device_busy_time */
	data->size = offsetof(struct cmbdata, device_busy_time);

	/* convert to nanoseconds */
	data->elapsed_time = (time * 1000) >> 12;

	/* copy data to new structure */
	data->ssch_rsch_count = cmb.ssch_rsch_count;
	data->sample_count = cmb.sample_count;

	/* time fields are converted to nanoseconds while copying */
	data->device_connect_time = time_to_nsec(cmb.device_connect_time);
	data->function_pending_time = time_to_nsec(cmb.function_pending_time);
	data->device_disconnect_time = time_to_nsec(cmb.device_disconnect_time);
	data->control_unit_queuing_time
		= time_to_nsec(cmb.control_unit_queuing_time);
	data->device_active_only_time
		= time_to_nsec(cmb.device_active_only_time);

	return 0;
}

static void
reset_cmb(struct ccw_device *cdev)
{
	struct cmb *cmb;
	spin_lock_irq(cdev->ccwlock);
	cmb = cdev->private->cmb;
	if (cmb)
		memset (cmb, 0, sizeof (*cmb));
	cdev->private->cmb_start_time = get_clock();
	spin_unlock_irq(cdev->ccwlock);
}

static struct attribute_group cmf_attr_group;

static struct cmb_operations cmbops_basic = {
	.alloc	= alloc_cmb,
	.free	= free_cmb,
	.set	= set_cmb,
	.read	= read_cmb,
	.readall    = readall_cmb,
	.reset	    = reset_cmb,
	.attr_group = &cmf_attr_group,
};

/* ******** extended cmb handling ********/

/**
 * struct cmbe - extended channel measurement block
 *
 * cmb as used by the hardware, may be in any 64 bit physical location,
 * the fields are described in z/Architecture Principles of Operation,
 * third edition, chapter 17.
 */
struct cmbe {
	u32 ssch_rsch_count;
	u32 sample_count;
	u32 device_connect_time;
	u32 function_pending_time;
	u32 device_disconnect_time;
	u32 control_unit_queuing_time;
	u32 device_active_only_time;
	u32 device_busy_time;
	u32 initial_command_response_time;
	u32 reserved[7];
};

/* kmalloc only guarantees 8 byte alignment, but we need cmbe
 * pointers to be naturally aligned. Make sure to allocate
 * enough space for two cmbes */
static inline struct cmbe* cmbe_align(struct cmbe *c)
{
	unsigned long addr;
	addr = ((unsigned long)c + sizeof (struct cmbe) - sizeof(long)) &
				 ~(sizeof (struct cmbe) - sizeof(long));
	return (struct cmbe*)addr;
}

static int
alloc_cmbe (struct ccw_device *cdev)
{
	struct cmbe *cmbe;
	cmbe = kmalloc (sizeof (*cmbe) * 2, GFP_KERNEL);
	if (!cmbe)
		return -ENOMEM;

	spin_lock_irq(cdev->ccwlock);
	if (cdev->private->cmb) {
		kfree(cmbe);
		spin_unlock_irq(cdev->ccwlock);
		return -EBUSY;
	}

	cdev->private->cmb = cmbe;
	spin_unlock_irq(cdev->ccwlock);

	/* activate global measurement if this is the first channel */
	spin_lock(&cmb_area.lock);
	if (list_empty(&cmb_area.list))
		cmf_activate(NULL, 1);
	list_add_tail(&cdev->private->cmb_list, &cmb_area.list);
	spin_unlock(&cmb_area.lock);

	return 0;
}

static void
free_cmbe (struct ccw_device *cdev)
{
	spin_lock_irq(cdev->ccwlock);
	kfree(cdev->private->cmb);
	cdev->private->cmb = NULL;
	spin_unlock_irq(cdev->ccwlock);

	/* deactivate global measurement if this is the last channel */
	spin_lock(&cmb_area.lock);
	list_del_init(&cdev->private->cmb_list);
	if (list_empty(&cmb_area.list))
		cmf_activate(NULL, 0);
	spin_unlock(&cmb_area.lock);
}

static int
set_cmbe(struct ccw_device *cdev, u32 mme)
{
	unsigned long mba;

	if (!cdev->private->cmb)
		return -EINVAL;
	mba = mme ? (unsigned long) cmbe_align(cdev->private->cmb) : 0;

	return set_schib_wait(cdev, mme, 1, mba);
}


u64
read_cmbe (struct ccw_device *cdev, int index)
{
	/* yes, we have to put it on the stack
	 * because the cmb must only be accessed
	 * atomically, e.g. with mvc */
	struct cmbe cmb;
	unsigned long flags;
	u32 val;

	spin_lock_irqsave(cdev->ccwlock, flags);
	if (!cdev->private->cmb) {
		spin_unlock_irqrestore(cdev->ccwlock, flags);
		return 0;
	}

	cmb = *cmbe_align(cdev->private->cmb);
	spin_unlock_irqrestore(cdev->ccwlock, flags);

	switch (index) {
	case cmb_ssch_rsch_count:
		return cmb.ssch_rsch_count;
	case cmb_sample_count:
		return cmb.sample_count;
	case cmb_device_connect_time:
		val = cmb.device_connect_time;
		break;
	case cmb_function_pending_time:
		val = cmb.function_pending_time;
		break;
	case cmb_device_disconnect_time:
		val = cmb.device_disconnect_time;
		break;
	case cmb_control_unit_queuing_time:
		val = cmb.control_unit_queuing_time;
		break;
	case cmb_device_active_only_time:
		val = cmb.device_active_only_time;
		break;
	case cmb_device_busy_time:
		val = cmb.device_busy_time;
		break;
	case cmb_initial_command_response_time:
		val = cmb.initial_command_response_time;
		break;
	default:
		return 0;
	}
	return time_to_avg_nsec(val, cmb.sample_count);
}

static int
readall_cmbe (struct ccw_device *cdev, struct cmbdata *data)
{
	/* yes, we have to put it on the stack
	 * because the cmb must only be accessed
	 * atomically, e.g. with mvc */
	struct cmbe cmb;
	unsigned long flags;
	u64 time;

	spin_lock_irqsave(cdev->ccwlock, flags);
	if (!cdev->private->cmb) {
		spin_unlock_irqrestore(cdev->ccwlock, flags);
		return -ENODEV;
	}

	cmb = *cmbe_align(cdev->private->cmb);
	time = get_clock() - cdev->private->cmb_start_time;
	spin_unlock_irqrestore(cdev->ccwlock, flags);

	memset (data, 0, sizeof(struct cmbdata));

	/* we only know values before device_busy_time */
	data->size = offsetof(struct cmbdata, device_busy_time);

	/* conver to nanoseconds */
	data->elapsed_time = (time * 1000) >> 12;

	/* copy data to new structure */
	data->ssch_rsch_count = cmb.ssch_rsch_count;
	data->sample_count = cmb.sample_count;

	/* time fields are converted to nanoseconds while copying */
	data->device_connect_time = time_to_nsec(cmb.device_connect_time);
	data->function_pending_time = time_to_nsec(cmb.function_pending_time);
	data->device_disconnect_time = time_to_nsec(cmb.device_disconnect_time);
	data->control_unit_queuing_time
		= time_to_nsec(cmb.control_unit_queuing_time);
	data->device_active_only_time
		= time_to_nsec(cmb.device_active_only_time);
	data->device_busy_time = time_to_nsec(cmb.device_busy_time);
	data->initial_command_response_time
		= time_to_nsec(cmb.initial_command_response_time);

	return 0;
}

static void
reset_cmbe(struct ccw_device *cdev)
{
	struct cmbe *cmb;
	spin_lock_irq(cdev->ccwlock);
	cmb = cmbe_align(cdev->private->cmb);
	if (cmb)
		memset (cmb, 0, sizeof (*cmb));
	cdev->private->cmb_start_time = get_clock();
	spin_unlock_irq(cdev->ccwlock);
}

static struct attribute_group cmf_attr_group_ext;

static struct cmb_operations cmbops_extended = {
	.alloc	    = alloc_cmbe,
	.free	    = free_cmbe,
	.set	    = set_cmbe,
	.read	    = read_cmbe,
	.readall    = readall_cmbe,
	.reset	    = reset_cmbe,
	.attr_group = &cmf_attr_group_ext,
};


static ssize_t
cmb_show_attr(struct device *dev, char *buf, enum cmb_index idx)
{
	return sprintf(buf, "%lld\n",
		(unsigned long long) cmf_read(to_ccwdev(dev), idx));
}

static ssize_t
cmb_show_avg_sample_interval(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct ccw_device *cdev;
	long interval;
	unsigned long count;

	cdev = to_ccwdev(dev);
	interval  = get_clock() - cdev->private->cmb_start_time;
	count = cmf_read(cdev, cmb_sample_count);
	if (count)
		interval /= count;
	else
		interval = -1;
	return sprintf(buf, "%ld\n", interval);
}

static ssize_t
cmb_show_avg_utilization(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct cmbdata data;
	u64 utilization;
	unsigned long t, u;
	int ret;

	ret = cmf_readall(to_ccwdev(dev), &data);
	if (ret)
		return ret;

	utilization = data.device_connect_time +
		      data.function_pending_time +
		      data.device_disconnect_time;

	/* shift to avoid long long division */
	while (-1ul < (data.elapsed_time | utilization)) {
		utilization >>= 8;
		data.elapsed_time >>= 8;
	}

	/* calculate value in 0.1 percent units */
	t = (unsigned long) data.elapsed_time / 1000;
	u = (unsigned long) utilization / t;

	return sprintf(buf, "%02ld.%01ld%%\n", u/ 10, u - (u/ 10) * 10);
}

#define cmf_attr(name) \
static ssize_t show_ ## name (struct device * dev, struct device_attribute *attr, char * buf) \
{ return cmb_show_attr((dev), buf, cmb_ ## name); } \
static DEVICE_ATTR(name, 0444, show_ ## name, NULL);

#define cmf_attr_avg(name) \
static ssize_t show_avg_ ## name (struct device * dev, struct device_attribute *attr, char * buf) \
{ return cmb_show_attr((dev), buf, cmb_ ## name); } \
static DEVICE_ATTR(avg_ ## name, 0444, show_avg_ ## name, NULL);

cmf_attr(ssch_rsch_count);
cmf_attr(sample_count);
cmf_attr_avg(device_connect_time);
cmf_attr_avg(function_pending_time);
cmf_attr_avg(device_disconnect_time);
cmf_attr_avg(control_unit_queuing_time);
cmf_attr_avg(device_active_only_time);
cmf_attr_avg(device_busy_time);
cmf_attr_avg(initial_command_response_time);

static DEVICE_ATTR(avg_sample_interval, 0444, cmb_show_avg_sample_interval, NULL);
static DEVICE_ATTR(avg_utilization, 0444, cmb_show_avg_utilization, NULL);

static struct attribute *cmf_attributes[] = {
	&dev_attr_avg_sample_interval.attr,
	&dev_attr_avg_utilization.attr,
	&dev_attr_ssch_rsch_count.attr,
	&dev_attr_sample_count.attr,
	&dev_attr_avg_device_connect_time.attr,
	&dev_attr_avg_function_pending_time.attr,
	&dev_attr_avg_device_disconnect_time.attr,
	&dev_attr_avg_control_unit_queuing_time.attr,
	&dev_attr_avg_device_active_only_time.attr,
	0,
};

static struct attribute_group cmf_attr_group = {
	.name  = "cmf",
	.attrs = cmf_attributes,
};

static struct attribute *cmf_attributes_ext[] = {
	&dev_attr_avg_sample_interval.attr,
	&dev_attr_avg_utilization.attr,
	&dev_attr_ssch_rsch_count.attr,
	&dev_attr_sample_count.attr,
	&dev_attr_avg_device_connect_time.attr,
	&dev_attr_avg_function_pending_time.attr,
	&dev_attr_avg_device_disconnect_time.attr,
	&dev_attr_avg_control_unit_queuing_time.attr,
	&dev_attr_avg_device_active_only_time.attr,
	&dev_attr_avg_device_busy_time.attr,
	&dev_attr_avg_initial_command_response_time.attr,
	0,
};

static struct attribute_group cmf_attr_group_ext = {
	.name  = "cmf",
	.attrs = cmf_attributes_ext,
};

static ssize_t cmb_enable_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "%d\n", to_ccwdev(dev)->private->cmb ? 1 : 0);
}

static ssize_t cmb_enable_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t c)
{
	struct ccw_device *cdev;
	int ret;

	cdev = to_ccwdev(dev);

	switch (buf[0]) {
	case '0':
		ret = disable_cmf(cdev);
		if (ret)
			printk(KERN_INFO "disable_cmf failed (%d)\n", ret);
		break;
	case '1':
		ret = enable_cmf(cdev);
		if (ret && ret != -EBUSY)
			printk(KERN_INFO "enable_cmf failed (%d)\n", ret);
		break;
	}

	return c;
}

DEVICE_ATTR(cmb_enable, 0644, cmb_enable_show, cmb_enable_store);

/* enable_cmf/disable_cmf: module interface for cmf (de)activation */
int
enable_cmf(struct ccw_device *cdev)
{
	int ret;

	ret = cmbops->alloc(cdev);
	cmbops->reset(cdev);
	if (ret)
		return ret;
	ret = cmbops->set(cdev, 2);
	if (ret) {
		cmbops->free(cdev);
		return ret;
	}
	ret = sysfs_create_group(&cdev->dev.kobj, cmbops->attr_group);
	if (!ret)
		return 0;
	cmbops->set(cdev, 0);  //FIXME: this can fail
	cmbops->free(cdev);
	return ret;
}

int
disable_cmf(struct ccw_device *cdev)
{
	int ret;

	ret = cmbops->set(cdev, 0);
	if (ret)
		return ret;
	cmbops->free(cdev);
	sysfs_remove_group(&cdev->dev.kobj, cmbops->attr_group);
	return ret;
}

u64
cmf_read(struct ccw_device *cdev, int index)
{
	return cmbops->read(cdev, index);
}

int
cmf_readall(struct ccw_device *cdev, struct cmbdata *data)
{
	return cmbops->readall(cdev, data);
}

static int __init
init_cmf(void)
{
	char *format_string;
	char *detect_string = "parameter";

	/* We cannot really autoprobe this. If the user did not give a parameter,
	   see if we are running on z990 or up, otherwise fall back to basic mode. */

	if (format == CMF_AUTODETECT) {
		if (!css_characteristics_avail ||
		    !css_general_characteristics.ext_mb) {
			format = CMF_BASIC;
		} else {
			format = CMF_EXTENDED;
		}
		detect_string = "autodetected";
	} else {
		detect_string = "parameter";
	}

	switch (format) {
	case CMF_BASIC:
		format_string = "basic";
		cmbops = &cmbops_basic;
		if (cmb_area.num_channels > 4096 || cmb_area.num_channels < 1) {
			printk(KERN_ERR "Basic channel measurement facility"
					" can only use 1 to 4096 devices\n"
			       KERN_ERR "when the cmf driver is built"
					" as a loadable module\n");
			return 1;
		}
		break;
	case CMF_EXTENDED:
 		format_string = "extended";
		cmbops = &cmbops_extended;
		break;
	default:
		printk(KERN_ERR "Invalid format %d for channel "
			"measurement facility\n", format);
		return 1;
	}

	printk(KERN_INFO "Channel measurement facility using %s format (%s)\n",
		format_string, detect_string);
	return 0;
}

module_init(init_cmf);


MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("channel measurement facility base driver\n"
		   "Copyright 2003 IBM Corporation\n");

EXPORT_SYMBOL_GPL(enable_cmf);
EXPORT_SYMBOL_GPL(disable_cmf);
EXPORT_SYMBOL_GPL(cmf_read);
EXPORT_SYMBOL_GPL(cmf_readall);