1/*
2 *  drivers/s390/cio/chp.c
3 *
4 *    Copyright IBM Corp. 1999,2007
5 *    Author(s): Cornelia Huck (cornelia.huck@de.ibm.com)
6 *		 Arnd Bergmann (arndb@de.ibm.com)
7 *		 Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
8 */
9
10#include <linux/bug.h>
11#include <linux/workqueue.h>
12#include <linux/spinlock.h>
13#include <linux/init.h>
14#include <linux/jiffies.h>
15#include <linux/wait.h>
16#include <linux/mutex.h>
17#include <asm/errno.h>
18#include <asm/chpid.h>
19#include <asm/sclp.h>
20
21#include "cio.h"
22#include "css.h"
23#include "ioasm.h"
24#include "cio_debug.h"
25#include "chp.h"
26
27#define to_channelpath(device) container_of(device, struct channel_path, dev)
28#define CHP_INFO_UPDATE_INTERVAL	1*HZ
29
30enum cfg_task_t {
31	cfg_none,
32	cfg_configure,
33	cfg_deconfigure
34};
35
36/* Map for pending configure tasks. */
37static enum cfg_task_t chp_cfg_task[__MAX_CSSID + 1][__MAX_CHPID + 1];
38static DEFINE_MUTEX(cfg_lock);
39static int cfg_busy;
40
41/* Map for channel-path status. */
42static struct sclp_chp_info chp_info;
43static DEFINE_MUTEX(info_lock);
44
45/* Time after which channel-path status may be outdated. */
46static unsigned long chp_info_expires;
47
48/* Workqueue to perform pending configure tasks. */
49static struct workqueue_struct *chp_wq;
50static struct work_struct cfg_work;
51
52/* Wait queue for configure completion events. */
53static wait_queue_head_t cfg_wait_queue;
54
55/* Return channel_path struct for given chpid. */
56static inline struct channel_path *chpid_to_chp(struct chp_id chpid)
57{
58	return css[chpid.cssid]->chps[chpid.id];
59}
60
61/* Set vary state for given chpid. */
62static void set_chp_logically_online(struct chp_id chpid, int onoff)
63{
64	chpid_to_chp(chpid)->state = onoff;
65}
66
67/* On succes return 0 if channel-path is varied offline, 1 if it is varied
68 * online. Return -ENODEV if channel-path is not registered. */
69int chp_get_status(struct chp_id chpid)
70{
71	return (chpid_to_chp(chpid) ? chpid_to_chp(chpid)->state : -ENODEV);
72}
73
74/**
75 * chp_get_sch_opm - return opm for subchannel
76 * @sch: subchannel
77 *
78 * Calculate and return the operational path mask (opm) based on the chpids
79 * used by the subchannel and the status of the associated channel-paths.
80 */
81u8 chp_get_sch_opm(struct subchannel *sch)
82{
83	struct chp_id chpid;
84	int opm;
85	int i;
86
87	opm = 0;
88	chp_id_init(&chpid);
89	for (i=0; i < 8; i++) {
90		opm <<= 1;
91		chpid.id = sch->schib.pmcw.chpid[i];
92		if (chp_get_status(chpid) != 0)
93			opm |= 1;
94	}
95	return opm;
96}
97
98/**
99 * chp_is_registered - check if a channel-path is registered
100 * @chpid: channel-path ID
101 *
102 * Return non-zero if a channel-path with the given chpid is registered,
103 * zero otherwise.
104 */
105int chp_is_registered(struct chp_id chpid)
106{
107	return chpid_to_chp(chpid) != NULL;
108}
109
110/*
111 * Function: s390_vary_chpid
112 * Varies the specified chpid online or offline
113 */
114static int s390_vary_chpid(struct chp_id chpid, int on)
115{
116	char dbf_text[15];
117	int status;
118
119	sprintf(dbf_text, on?"varyon%x.%02x":"varyoff%x.%02x", chpid.cssid,
120		chpid.id);
121	CIO_TRACE_EVENT( 2, dbf_text);
122
123	status = chp_get_status(chpid);
124	if (status < 0) {
125		printk(KERN_ERR "Can't vary unknown chpid %x.%02x\n",
126		       chpid.cssid, chpid.id);
127		return -EINVAL;
128	}
129
130	if (!on && !status) {
131		printk(KERN_ERR "chpid %x.%02x is already offline\n",
132		       chpid.cssid, chpid.id);
133		return -EINVAL;
134	}
135
136	set_chp_logically_online(chpid, on);
137	chsc_chp_vary(chpid, on);
138	return 0;
139}
140
141/*
142 * Channel measurement related functions
143 */
144static ssize_t chp_measurement_chars_read(struct kobject *kobj, char *buf,
145					  loff_t off, size_t count)
146{
147	struct channel_path *chp;
148	unsigned int size;
149
150	chp = to_channelpath(container_of(kobj, struct device, kobj));
151	if (!chp->cmg_chars)
152		return 0;
153
154	size = sizeof(struct cmg_chars);
155
156	if (off > size)
157		return 0;
158	if (off + count > size)
159		count = size - off;
160	memcpy(buf, chp->cmg_chars + off, count);
161	return count;
162}
163
164static struct bin_attribute chp_measurement_chars_attr = {
165	.attr = {
166		.name = "measurement_chars",
167		.mode = S_IRUSR,
168		.owner = THIS_MODULE,
169	},
170	.size = sizeof(struct cmg_chars),
171	.read = chp_measurement_chars_read,
172};
173
174static void chp_measurement_copy_block(struct cmg_entry *buf,
175				       struct channel_subsystem *css,
176				       struct chp_id chpid)
177{
178	void *area;
179	struct cmg_entry *entry, reference_buf;
180	int idx;
181
182	if (chpid.id < 128) {
183		area = css->cub_addr1;
184		idx = chpid.id;
185	} else {
186		area = css->cub_addr2;
187		idx = chpid.id - 128;
188	}
189	entry = area + (idx * sizeof(struct cmg_entry));
190	do {
191		memcpy(buf, entry, sizeof(*entry));
192		memcpy(&reference_buf, entry, sizeof(*entry));
193	} while (reference_buf.values[0] != buf->values[0]);
194}
195
196static ssize_t chp_measurement_read(struct kobject *kobj, char *buf,
197				    loff_t off, size_t count)
198{
199	struct channel_path *chp;
200	struct channel_subsystem *css;
201	unsigned int size;
202
203	chp = to_channelpath(container_of(kobj, struct device, kobj));
204	css = to_css(chp->dev.parent);
205
206	size = sizeof(struct cmg_entry);
207
208	/* Only allow single reads. */
209	if (off || count < size)
210		return 0;
211	chp_measurement_copy_block((struct cmg_entry *)buf, css, chp->chpid);
212	count = size;
213	return count;
214}
215
216static struct bin_attribute chp_measurement_attr = {
217	.attr = {
218		.name = "measurement",
219		.mode = S_IRUSR,
220		.owner = THIS_MODULE,
221	},
222	.size = sizeof(struct cmg_entry),
223	.read = chp_measurement_read,
224};
225
226void chp_remove_cmg_attr(struct channel_path *chp)
227{
228	device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
229	device_remove_bin_file(&chp->dev, &chp_measurement_attr);
230}
231
232int chp_add_cmg_attr(struct channel_path *chp)
233{
234	int ret;
235
236	ret = device_create_bin_file(&chp->dev, &chp_measurement_chars_attr);
237	if (ret)
238		return ret;
239	ret = device_create_bin_file(&chp->dev, &chp_measurement_attr);
240	if (ret)
241		device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
242	return ret;
243}
244
245/*
246 * Files for the channel path entries.
247 */
248static ssize_t chp_status_show(struct device *dev,
249			       struct device_attribute *attr, char *buf)
250{
251	struct channel_path *chp = container_of(dev, struct channel_path, dev);
252
253	if (!chp)
254		return 0;
255	return (chp_get_status(chp->chpid) ? sprintf(buf, "online\n") :
256		sprintf(buf, "offline\n"));
257}
258
259static ssize_t chp_status_write(struct device *dev,
260				struct device_attribute *attr,
261				const char *buf, size_t count)
262{
263	struct channel_path *cp = container_of(dev, struct channel_path, dev);
264	char cmd[10];
265	int num_args;
266	int error;
267
268	num_args = sscanf(buf, "%5s", cmd);
269	if (!num_args)
270		return count;
271
272	if (!strnicmp(cmd, "on", 2) || !strcmp(cmd, "1"))
273		error = s390_vary_chpid(cp->chpid, 1);
274	else if (!strnicmp(cmd, "off", 3) || !strcmp(cmd, "0"))
275		error = s390_vary_chpid(cp->chpid, 0);
276	else
277		error = -EINVAL;
278
279	return error < 0 ? error : count;
280
281}
282
283static DEVICE_ATTR(status, 0644, chp_status_show, chp_status_write);
284
285static ssize_t chp_configure_show(struct device *dev,
286				  struct device_attribute *attr, char *buf)
287{
288	struct channel_path *cp;
289	int status;
290
291	cp = container_of(dev, struct channel_path, dev);
292	status = chp_info_get_status(cp->chpid);
293	if (status < 0)
294		return status;
295
296	return snprintf(buf, PAGE_SIZE, "%d\n", status);
297}
298
299static int cfg_wait_idle(void);
300
301static ssize_t chp_configure_write(struct device *dev,
302				   struct device_attribute *attr,
303				   const char *buf, size_t count)
304{
305	struct channel_path *cp;
306	int val;
307	char delim;
308
309	if (sscanf(buf, "%d %c", &val, &delim) != 1)
310		return -EINVAL;
311	if (val != 0 && val != 1)
312		return -EINVAL;
313	cp = container_of(dev, struct channel_path, dev);
314	chp_cfg_schedule(cp->chpid, val);
315	cfg_wait_idle();
316
317	return count;
318}
319
320static DEVICE_ATTR(configure, 0644, chp_configure_show, chp_configure_write);
321
322static ssize_t chp_type_show(struct device *dev, struct device_attribute *attr,
323			     char *buf)
324{
325	struct channel_path *chp = container_of(dev, struct channel_path, dev);
326
327	if (!chp)
328		return 0;
329	return sprintf(buf, "%x\n", chp->desc.desc);
330}
331
332static DEVICE_ATTR(type, 0444, chp_type_show, NULL);
333
334static ssize_t chp_cmg_show(struct device *dev, struct device_attribute *attr,
335			    char *buf)
336{
337	struct channel_path *chp = to_channelpath(dev);
338
339	if (!chp)
340		return 0;
341	if (chp->cmg == -1) /* channel measurements not available */
342		return sprintf(buf, "unknown\n");
343	return sprintf(buf, "%x\n", chp->cmg);
344}
345
346static DEVICE_ATTR(cmg, 0444, chp_cmg_show, NULL);
347
348static ssize_t chp_shared_show(struct device *dev,
349			       struct device_attribute *attr, char *buf)
350{
351	struct channel_path *chp = to_channelpath(dev);
352
353	if (!chp)
354		return 0;
355	if (chp->shared == -1) /* channel measurements not available */
356		return sprintf(buf, "unknown\n");
357	return sprintf(buf, "%x\n", chp->shared);
358}
359
360static DEVICE_ATTR(shared, 0444, chp_shared_show, NULL);
361
362static struct attribute * chp_attrs[] = {
363	&dev_attr_status.attr,
364	&dev_attr_configure.attr,
365	&dev_attr_type.attr,
366	&dev_attr_cmg.attr,
367	&dev_attr_shared.attr,
368	NULL,
369};
370
371static struct attribute_group chp_attr_group = {
372	.attrs = chp_attrs,
373};
374
375static void chp_release(struct device *dev)
376{
377	struct channel_path *cp;
378
379	cp = container_of(dev, struct channel_path, dev);
380	kfree(cp);
381}
382
383/**
384 * chp_new - register a new channel-path
385 * @chpid - channel-path ID
386 *
387 * Create and register data structure representing new channel-path. Return
388 * zero on success, non-zero otherwise.
389 */
390int chp_new(struct chp_id chpid)
391{
392	struct channel_path *chp;
393	int ret;
394
395	if (chp_is_registered(chpid))
396		return 0;
397	chp = kzalloc(sizeof(struct channel_path), GFP_KERNEL);
398	if (!chp)
399		return -ENOMEM;
400
401	/* fill in status, etc. */
402	chp->chpid = chpid;
403	chp->state = 1;
404	chp->dev.parent = &css[chpid.cssid]->device;
405	chp->dev.release = chp_release;
406	snprintf(chp->dev.bus_id, BUS_ID_SIZE, "chp%x.%02x", chpid.cssid,
407		 chpid.id);
408
409	/* Obtain channel path description and fill it in. */
410	ret = chsc_determine_channel_path_description(chpid, &chp->desc);
411	if (ret)
412		goto out_free;
413	if ((chp->desc.flags & 0x80) == 0) {
414		ret = -ENODEV;
415		goto out_free;
416	}
417	/* Get channel-measurement characteristics. */
418	if (css_characteristics_avail && css_chsc_characteristics.scmc
419	    && css_chsc_characteristics.secm) {
420		ret = chsc_get_channel_measurement_chars(chp);
421		if (ret)
422			goto out_free;
423	} else {
424		static int msg_done;
425
426		if (!msg_done) {
427			printk(KERN_WARNING "cio: Channel measurements not "
428			       "available, continuing.\n");
429			msg_done = 1;
430		}
431		chp->cmg = -1;
432	}
433
434	/* make it known to the system */
435	ret = device_register(&chp->dev);
436	if (ret) {
437		printk(KERN_WARNING "%s: could not register %x.%02x\n",
438		       __func__, chpid.cssid, chpid.id);
439		goto out_free;
440	}
441	ret = sysfs_create_group(&chp->dev.kobj, &chp_attr_group);
442	if (ret) {
443		device_unregister(&chp->dev);
444		goto out_free;
445	}
446	mutex_lock(&css[chpid.cssid]->mutex);
447	if (css[chpid.cssid]->cm_enabled) {
448		ret = chp_add_cmg_attr(chp);
449		if (ret) {
450			sysfs_remove_group(&chp->dev.kobj, &chp_attr_group);
451			device_unregister(&chp->dev);
452			mutex_unlock(&css[chpid.cssid]->mutex);
453			goto out_free;
454		}
455	}
456	css[chpid.cssid]->chps[chpid.id] = chp;
457	mutex_unlock(&css[chpid.cssid]->mutex);
458	return ret;
459out_free:
460	kfree(chp);
461	return ret;
462}
463
464/**
465 * chp_get_chp_desc - return newly allocated channel-path description
466 * @chpid: channel-path ID
467 *
468 * On success return a newly allocated copy of the channel-path description
469 * data associated with the given channel-path ID. Return %NULL on error.
470 */
471void *chp_get_chp_desc(struct chp_id chpid)
472{
473	struct channel_path *chp;
474	struct channel_path_desc *desc;
475
476	chp = chpid_to_chp(chpid);
477	if (!chp)
478		return NULL;
479	desc = kmalloc(sizeof(struct channel_path_desc), GFP_KERNEL);
480	if (!desc)
481		return NULL;
482	memcpy(desc, &chp->desc, sizeof(struct channel_path_desc));
483	return desc;
484}
485
486/**
487 * chp_process_crw - process channel-path status change
488 * @id: channel-path ID number
489 * @status: non-zero if channel-path has become available, zero otherwise
490 *
491 * Handle channel-report-words indicating that the status of a channel-path
492 * has changed.
493 */
494void chp_process_crw(int id, int status)
495{
496	struct chp_id chpid;
497
498	chp_id_init(&chpid);
499	chpid.id = id;
500	if (status) {
501		if (!chp_is_registered(chpid))
502			chp_new(chpid);
503		chsc_chp_online(chpid);
504	} else
505		chsc_chp_offline(chpid);
506}
507
508static inline int info_bit_num(struct chp_id id)
509{
510	return id.id + id.cssid * (__MAX_CHPID + 1);
511}
512
513/* Force chp_info refresh on next call to info_validate(). */
514static void info_expire(void)
515{
516	mutex_lock(&info_lock);
517	chp_info_expires = jiffies - 1;
518	mutex_unlock(&info_lock);
519}
520
521/* Ensure that chp_info is up-to-date. */
522static int info_update(void)
523{
524	int rc;
525
526	mutex_lock(&info_lock);
527	rc = 0;
528	if (time_after(jiffies, chp_info_expires)) {
529		/* Data is too old, update. */
530		rc = sclp_chp_read_info(&chp_info);
531		chp_info_expires = jiffies + CHP_INFO_UPDATE_INTERVAL ;
532	}
533	mutex_unlock(&info_lock);
534
535	return rc;
536}
537
538/**
539 * chp_info_get_status - retrieve configure status of a channel-path
540 * @chpid: channel-path ID
541 *
542 * On success, return 0 for standby, 1 for configured, 2 for reserved,
543 * 3 for not recognized. Return negative error code on error.
544 */
545int chp_info_get_status(struct chp_id chpid)
546{
547	int rc;
548	int bit;
549
550	rc = info_update();
551	if (rc)
552		return rc;
553
554	bit = info_bit_num(chpid);
555	mutex_lock(&info_lock);
556	if (!chp_test_bit(chp_info.recognized, bit))
557		rc = CHP_STATUS_NOT_RECOGNIZED;
558	else if (chp_test_bit(chp_info.configured, bit))
559		rc = CHP_STATUS_CONFIGURED;
560	else if (chp_test_bit(chp_info.standby, bit))
561		rc = CHP_STATUS_STANDBY;
562	else
563		rc = CHP_STATUS_RESERVED;
564	mutex_unlock(&info_lock);
565
566	return rc;
567}
568
569/* Return configure task for chpid. */
570static enum cfg_task_t cfg_get_task(struct chp_id chpid)
571{
572	return chp_cfg_task[chpid.cssid][chpid.id];
573}
574
575/* Set configure task for chpid. */
576static void cfg_set_task(struct chp_id chpid, enum cfg_task_t cfg)
577{
578	chp_cfg_task[chpid.cssid][chpid.id] = cfg;
579}
580
581/* Perform one configure/deconfigure request. Reschedule work function until
582 * last request. */
583static void cfg_func(struct work_struct *work)
584{
585	struct chp_id chpid;
586	enum cfg_task_t t;
587
588	mutex_lock(&cfg_lock);
589	t = cfg_none;
590	chp_id_for_each(&chpid) {
591		t = cfg_get_task(chpid);
592		if (t != cfg_none) {
593			cfg_set_task(chpid, cfg_none);
594			break;
595		}
596	}
597	mutex_unlock(&cfg_lock);
598
599	switch (t) {
600	case cfg_configure:
601		sclp_chp_configure(chpid);
602		info_expire();
603		chsc_chp_online(chpid);
604		break;
605	case cfg_deconfigure:
606		sclp_chp_deconfigure(chpid);
607		info_expire();
608		chsc_chp_offline(chpid);
609		break;
610	case cfg_none:
611		/* Get updated information after last change. */
612		info_update();
613		mutex_lock(&cfg_lock);
614		cfg_busy = 0;
615		mutex_unlock(&cfg_lock);
616		wake_up_interruptible(&cfg_wait_queue);
617		return;
618	}
619	queue_work(chp_wq, &cfg_work);
620}
621
622/**
623 * chp_cfg_schedule - schedule chpid configuration request
624 * @chpid - channel-path ID
625 * @configure - Non-zero for configure, zero for deconfigure
626 *
627 * Schedule a channel-path configuration/deconfiguration request.
628 */
629void chp_cfg_schedule(struct chp_id chpid, int configure)
630{
631	CIO_MSG_EVENT(2, "chp_cfg_sched%x.%02x=%d\n", chpid.cssid, chpid.id,
632		      configure);
633	mutex_lock(&cfg_lock);
634	cfg_set_task(chpid, configure ? cfg_configure : cfg_deconfigure);
635	cfg_busy = 1;
636	mutex_unlock(&cfg_lock);
637	queue_work(chp_wq, &cfg_work);
638}
639
640/**
641 * chp_cfg_cancel_deconfigure - cancel chpid deconfiguration request
642 * @chpid - channel-path ID
643 *
644 * Cancel an active channel-path deconfiguration request if it has not yet
645 * been performed.
646 */
647void chp_cfg_cancel_deconfigure(struct chp_id chpid)
648{
649	CIO_MSG_EVENT(2, "chp_cfg_cancel:%x.%02x\n", chpid.cssid, chpid.id);
650	mutex_lock(&cfg_lock);
651	if (cfg_get_task(chpid) == cfg_deconfigure)
652		cfg_set_task(chpid, cfg_none);
653	mutex_unlock(&cfg_lock);
654}
655
656static int cfg_wait_idle(void)
657{
658	if (wait_event_interruptible(cfg_wait_queue, !cfg_busy))
659		return -ERESTARTSYS;
660	return 0;
661}
662
663static int __init chp_init(void)
664{
665	struct chp_id chpid;
666
667	chp_wq = create_singlethread_workqueue("cio_chp");
668	if (!chp_wq)
669		return -ENOMEM;
670	INIT_WORK(&cfg_work, cfg_func);
671	init_waitqueue_head(&cfg_wait_queue);
672	if (info_update())
673		return 0;
674	/* Register available channel-paths. */
675	chp_id_for_each(&chpid) {
676		if (chp_info_get_status(chpid) != CHP_STATUS_NOT_RECOGNIZED)
677			chp_new(chpid);
678	}
679
680	return 0;
681}
682
683subsys_initcall(chp_init);
684