1/*
2 *  drivers/s390/cio/chp.c
3 *
4 *    Copyright IBM Corp. 1999,2010
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/export.h>
14#include <linux/sched.h>
15#include <linux/init.h>
16#include <linux/jiffies.h>
17#include <linux/wait.h>
18#include <linux/mutex.h>
19#include <linux/errno.h>
20#include <linux/slab.h>
21#include <asm/chpid.h>
22#include <asm/sclp.h>
23#include <asm/crw.h>
24
25#include "cio.h"
26#include "css.h"
27#include "ioasm.h"
28#include "cio_debug.h"
29#include "chp.h"
30
31#define to_channelpath(device) container_of(device, struct channel_path, dev)
32#define CHP_INFO_UPDATE_INTERVAL	1*HZ
33
34enum cfg_task_t {
35	cfg_none,
36	cfg_configure,
37	cfg_deconfigure
38};
39
40/* Map for pending configure tasks. */
41static enum cfg_task_t chp_cfg_task[__MAX_CSSID + 1][__MAX_CHPID + 1];
42static DEFINE_MUTEX(cfg_lock);
43static int cfg_busy;
44
45/* Map for channel-path status. */
46static struct sclp_chp_info chp_info;
47static DEFINE_MUTEX(info_lock);
48
49/* Time after which channel-path status may be outdated. */
50static unsigned long chp_info_expires;
51
52/* Workqueue to perform pending configure tasks. */
53static struct workqueue_struct *chp_wq;
54static struct work_struct cfg_work;
55
56/* Wait queue for configure completion events. */
57static wait_queue_head_t cfg_wait_queue;
58
59/* Set vary state for given chpid. */
60static void set_chp_logically_online(struct chp_id chpid, int onoff)
61{
62	chpid_to_chp(chpid)->state = onoff;
63}
64
65/* On success return 0 if channel-path is varied offline, 1 if it is varied
66 * online. Return -ENODEV if channel-path is not registered. */
67int chp_get_status(struct chp_id chpid)
68{
69	return (chpid_to_chp(chpid) ? chpid_to_chp(chpid)->state : -ENODEV);
70}
71
72/**
73 * chp_get_sch_opm - return opm for subchannel
74 * @sch: subchannel
75 *
76 * Calculate and return the operational path mask (opm) based on the chpids
77 * used by the subchannel and the status of the associated channel-paths.
78 */
79u8 chp_get_sch_opm(struct subchannel *sch)
80{
81	struct chp_id chpid;
82	int opm;
83	int i;
84
85	opm = 0;
86	chp_id_init(&chpid);
87	for (i = 0; i < 8; i++) {
88		opm <<= 1;
89		chpid.id = sch->schib.pmcw.chpid[i];
90		if (chp_get_status(chpid) != 0)
91			opm |= 1;
92	}
93	return opm;
94}
95EXPORT_SYMBOL_GPL(chp_get_sch_opm);
96
97/**
98 * chp_is_registered - check if a channel-path is registered
99 * @chpid: channel-path ID
100 *
101 * Return non-zero if a channel-path with the given chpid is registered,
102 * zero otherwise.
103 */
104int chp_is_registered(struct chp_id chpid)
105{
106	return chpid_to_chp(chpid) != NULL;
107}
108
109/*
110 * Function: s390_vary_chpid
111 * Varies the specified chpid online or offline
112 */
113static int s390_vary_chpid(struct chp_id chpid, int on)
114{
115	char dbf_text[15];
116	int status;
117
118	sprintf(dbf_text, on?"varyon%x.%02x":"varyoff%x.%02x", chpid.cssid,
119		chpid.id);
120	CIO_TRACE_EVENT(2, dbf_text);
121
122	status = chp_get_status(chpid);
123	if (!on && !status)
124		return 0;
125
126	set_chp_logically_online(chpid, on);
127	chsc_chp_vary(chpid, on);
128	return 0;
129}
130
131/*
132 * Channel measurement related functions
133 */
134static ssize_t chp_measurement_chars_read(struct file *filp,
135					  struct kobject *kobj,
136					  struct bin_attribute *bin_attr,
137					  char *buf, loff_t off, size_t count)
138{
139	struct channel_path *chp;
140	struct device *device;
141
142	device = container_of(kobj, struct device, kobj);
143	chp = to_channelpath(device);
144	if (!chp->cmg_chars)
145		return 0;
146
147	return memory_read_from_buffer(buf, count, &off,
148				chp->cmg_chars, sizeof(struct cmg_chars));
149}
150
151static struct bin_attribute chp_measurement_chars_attr = {
152	.attr = {
153		.name = "measurement_chars",
154		.mode = S_IRUSR,
155	},
156	.size = sizeof(struct cmg_chars),
157	.read = chp_measurement_chars_read,
158};
159
160static void chp_measurement_copy_block(struct cmg_entry *buf,
161				       struct channel_subsystem *css,
162				       struct chp_id chpid)
163{
164	void *area;
165	struct cmg_entry *entry, reference_buf;
166	int idx;
167
168	if (chpid.id < 128) {
169		area = css->cub_addr1;
170		idx = chpid.id;
171	} else {
172		area = css->cub_addr2;
173		idx = chpid.id - 128;
174	}
175	entry = area + (idx * sizeof(struct cmg_entry));
176	do {
177		memcpy(buf, entry, sizeof(*entry));
178		memcpy(&reference_buf, entry, sizeof(*entry));
179	} while (reference_buf.values[0] != buf->values[0]);
180}
181
182static ssize_t chp_measurement_read(struct file *filp, struct kobject *kobj,
183				    struct bin_attribute *bin_attr,
184				    char *buf, loff_t off, size_t count)
185{
186	struct channel_path *chp;
187	struct channel_subsystem *css;
188	struct device *device;
189	unsigned int size;
190
191	device = container_of(kobj, struct device, kobj);
192	chp = to_channelpath(device);
193	css = to_css(chp->dev.parent);
194
195	size = sizeof(struct cmg_entry);
196
197	/* Only allow single reads. */
198	if (off || count < size)
199		return 0;
200	chp_measurement_copy_block((struct cmg_entry *)buf, css, chp->chpid);
201	count = size;
202	return count;
203}
204
205static struct bin_attribute chp_measurement_attr = {
206	.attr = {
207		.name = "measurement",
208		.mode = S_IRUSR,
209	},
210	.size = sizeof(struct cmg_entry),
211	.read = chp_measurement_read,
212};
213
214void chp_remove_cmg_attr(struct channel_path *chp)
215{
216	device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
217	device_remove_bin_file(&chp->dev, &chp_measurement_attr);
218}
219
220int chp_add_cmg_attr(struct channel_path *chp)
221{
222	int ret;
223
224	ret = device_create_bin_file(&chp->dev, &chp_measurement_chars_attr);
225	if (ret)
226		return ret;
227	ret = device_create_bin_file(&chp->dev, &chp_measurement_attr);
228	if (ret)
229		device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
230	return ret;
231}
232
233/*
234 * Files for the channel path entries.
235 */
236static ssize_t chp_status_show(struct device *dev,
237			       struct device_attribute *attr, char *buf)
238{
239	struct channel_path *chp = to_channelpath(dev);
240	int status;
241
242	mutex_lock(&chp->lock);
243	status = chp->state;
244	mutex_unlock(&chp->lock);
245
246	return status ? sprintf(buf, "online\n") : sprintf(buf, "offline\n");
247}
248
249static ssize_t chp_status_write(struct device *dev,
250				struct device_attribute *attr,
251				const char *buf, size_t count)
252{
253	struct channel_path *cp = to_channelpath(dev);
254	char cmd[10];
255	int num_args;
256	int error;
257
258	num_args = sscanf(buf, "%5s", cmd);
259	if (!num_args)
260		return count;
261
262	if (!strnicmp(cmd, "on", 2) || !strcmp(cmd, "1")) {
263		mutex_lock(&cp->lock);
264		error = s390_vary_chpid(cp->chpid, 1);
265		mutex_unlock(&cp->lock);
266	} else if (!strnicmp(cmd, "off", 3) || !strcmp(cmd, "0")) {
267		mutex_lock(&cp->lock);
268		error = s390_vary_chpid(cp->chpid, 0);
269		mutex_unlock(&cp->lock);
270	} else
271		error = -EINVAL;
272
273	return error < 0 ? error : count;
274}
275
276static DEVICE_ATTR(status, 0644, chp_status_show, chp_status_write);
277
278static ssize_t chp_configure_show(struct device *dev,
279				  struct device_attribute *attr, char *buf)
280{
281	struct channel_path *cp;
282	int status;
283
284	cp = to_channelpath(dev);
285	status = chp_info_get_status(cp->chpid);
286	if (status < 0)
287		return status;
288
289	return snprintf(buf, PAGE_SIZE, "%d\n", status);
290}
291
292static int cfg_wait_idle(void);
293
294static ssize_t chp_configure_write(struct device *dev,
295				   struct device_attribute *attr,
296				   const char *buf, size_t count)
297{
298	struct channel_path *cp;
299	int val;
300	char delim;
301
302	if (sscanf(buf, "%d %c", &val, &delim) != 1)
303		return -EINVAL;
304	if (val != 0 && val != 1)
305		return -EINVAL;
306	cp = to_channelpath(dev);
307	chp_cfg_schedule(cp->chpid, val);
308	cfg_wait_idle();
309
310	return count;
311}
312
313static DEVICE_ATTR(configure, 0644, chp_configure_show, chp_configure_write);
314
315static ssize_t chp_type_show(struct device *dev, struct device_attribute *attr,
316			     char *buf)
317{
318	struct channel_path *chp = to_channelpath(dev);
319	u8 type;
320
321	mutex_lock(&chp->lock);
322	type = chp->desc.desc;
323	mutex_unlock(&chp->lock);
324	return sprintf(buf, "%x\n", type);
325}
326
327static DEVICE_ATTR(type, 0444, chp_type_show, NULL);
328
329static ssize_t chp_cmg_show(struct device *dev, struct device_attribute *attr,
330			    char *buf)
331{
332	struct channel_path *chp = to_channelpath(dev);
333
334	if (!chp)
335		return 0;
336	if (chp->cmg == -1) /* channel measurements not available */
337		return sprintf(buf, "unknown\n");
338	return sprintf(buf, "%x\n", chp->cmg);
339}
340
341static DEVICE_ATTR(cmg, 0444, chp_cmg_show, NULL);
342
343static ssize_t chp_shared_show(struct device *dev,
344			       struct device_attribute *attr, char *buf)
345{
346	struct channel_path *chp = to_channelpath(dev);
347
348	if (!chp)
349		return 0;
350	if (chp->shared == -1) /* channel measurements not available */
351		return sprintf(buf, "unknown\n");
352	return sprintf(buf, "%x\n", chp->shared);
353}
354
355static DEVICE_ATTR(shared, 0444, chp_shared_show, NULL);
356
357static struct attribute *chp_attrs[] = {
358	&dev_attr_status.attr,
359	&dev_attr_configure.attr,
360	&dev_attr_type.attr,
361	&dev_attr_cmg.attr,
362	&dev_attr_shared.attr,
363	NULL,
364};
365
366static struct attribute_group chp_attr_group = {
367	.attrs = chp_attrs,
368};
369
370static void chp_release(struct device *dev)
371{
372	struct channel_path *cp;
373
374	cp = to_channelpath(dev);
375	kfree(cp);
376}
377
378/**
379 * chp_new - register a new channel-path
380 * @chpid - channel-path ID
381 *
382 * Create and register data structure representing new channel-path. Return
383 * zero on success, non-zero otherwise.
384 */
385int chp_new(struct chp_id chpid)
386{
387	struct channel_path *chp;
388	int ret;
389
390	if (chp_is_registered(chpid))
391		return 0;
392	chp = kzalloc(sizeof(struct channel_path), GFP_KERNEL);
393	if (!chp)
394		return -ENOMEM;
395
396	/* fill in status, etc. */
397	chp->chpid = chpid;
398	chp->state = 1;
399	chp->dev.parent = &channel_subsystems[chpid.cssid]->device;
400	chp->dev.release = chp_release;
401	mutex_init(&chp->lock);
402
403	/* Obtain channel path description and fill it in. */
404	ret = chsc_determine_base_channel_path_desc(chpid, &chp->desc);
405	if (ret)
406		goto out_free;
407	if ((chp->desc.flags & 0x80) == 0) {
408		ret = -ENODEV;
409		goto out_free;
410	}
411	/* Get channel-measurement characteristics. */
412	if (css_chsc_characteristics.scmc && css_chsc_characteristics.secm) {
413		ret = chsc_get_channel_measurement_chars(chp);
414		if (ret)
415			goto out_free;
416	} else {
417		chp->cmg = -1;
418	}
419	dev_set_name(&chp->dev, "chp%x.%02x", chpid.cssid, chpid.id);
420
421	/* make it known to the system */
422	ret = device_register(&chp->dev);
423	if (ret) {
424		CIO_MSG_EVENT(0, "Could not register chp%x.%02x: %d\n",
425			      chpid.cssid, chpid.id, ret);
426		put_device(&chp->dev);
427		goto out;
428	}
429	ret = sysfs_create_group(&chp->dev.kobj, &chp_attr_group);
430	if (ret) {
431		device_unregister(&chp->dev);
432		goto out;
433	}
434	mutex_lock(&channel_subsystems[chpid.cssid]->mutex);
435	if (channel_subsystems[chpid.cssid]->cm_enabled) {
436		ret = chp_add_cmg_attr(chp);
437		if (ret) {
438			sysfs_remove_group(&chp->dev.kobj, &chp_attr_group);
439			device_unregister(&chp->dev);
440			mutex_unlock(&channel_subsystems[chpid.cssid]->mutex);
441			goto out;
442		}
443	}
444	channel_subsystems[chpid.cssid]->chps[chpid.id] = chp;
445	mutex_unlock(&channel_subsystems[chpid.cssid]->mutex);
446	goto out;
447out_free:
448	kfree(chp);
449out:
450	return ret;
451}
452
453/**
454 * chp_get_chp_desc - return newly allocated channel-path description
455 * @chpid: channel-path ID
456 *
457 * On success return a newly allocated copy of the channel-path description
458 * data associated with the given channel-path ID. Return %NULL on error.
459 */
460void *chp_get_chp_desc(struct chp_id chpid)
461{
462	struct channel_path *chp;
463	struct channel_path_desc *desc;
464
465	chp = chpid_to_chp(chpid);
466	if (!chp)
467		return NULL;
468	desc = kmalloc(sizeof(struct channel_path_desc), GFP_KERNEL);
469	if (!desc)
470		return NULL;
471
472	mutex_lock(&chp->lock);
473	memcpy(desc, &chp->desc, sizeof(struct channel_path_desc));
474	mutex_unlock(&chp->lock);
475	return desc;
476}
477
478/**
479 * chp_process_crw - process channel-path status change
480 * @crw0: channel report-word to handler
481 * @crw1: second channel-report word (always NULL)
482 * @overflow: crw overflow indication
483 *
484 * Handle channel-report-words indicating that the status of a channel-path
485 * has changed.
486 */
487static void chp_process_crw(struct crw *crw0, struct crw *crw1,
488			    int overflow)
489{
490	struct chp_id chpid;
491
492	if (overflow) {
493		css_schedule_eval_all();
494		return;
495	}
496	CIO_CRW_EVENT(2, "CRW reports slct=%d, oflw=%d, "
497		      "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
498		      crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
499		      crw0->erc, crw0->rsid);
500	/*
501	 * Check for solicited machine checks. These are
502	 * created by reset channel path and need not be
503	 * handled here.
504	 */
505	if (crw0->slct) {
506		CIO_CRW_EVENT(2, "solicited machine check for "
507			      "channel path %02X\n", crw0->rsid);
508		return;
509	}
510	chp_id_init(&chpid);
511	chpid.id = crw0->rsid;
512	switch (crw0->erc) {
513	case CRW_ERC_IPARM: /* Path has come. */
514		if (!chp_is_registered(chpid))
515			chp_new(chpid);
516		chsc_chp_online(chpid);
517		break;
518	case CRW_ERC_PERRI: /* Path has gone. */
519	case CRW_ERC_PERRN:
520		chsc_chp_offline(chpid);
521		break;
522	default:
523		CIO_CRW_EVENT(2, "Don't know how to handle erc=%x\n",
524			      crw0->erc);
525	}
526}
527
528int chp_ssd_get_mask(struct chsc_ssd_info *ssd, struct chp_link *link)
529{
530	int i;
531	int mask;
532
533	for (i = 0; i < 8; i++) {
534		mask = 0x80 >> i;
535		if (!(ssd->path_mask & mask))
536			continue;
537		if (!chp_id_is_equal(&ssd->chpid[i], &link->chpid))
538			continue;
539		if ((ssd->fla_valid_mask & mask) &&
540		    ((ssd->fla[i] & link->fla_mask) != link->fla))
541			continue;
542		return mask;
543	}
544	return 0;
545}
546EXPORT_SYMBOL_GPL(chp_ssd_get_mask);
547
548static inline int info_bit_num(struct chp_id id)
549{
550	return id.id + id.cssid * (__MAX_CHPID + 1);
551}
552
553/* Force chp_info refresh on next call to info_validate(). */
554static void info_expire(void)
555{
556	mutex_lock(&info_lock);
557	chp_info_expires = jiffies - 1;
558	mutex_unlock(&info_lock);
559}
560
561/* Ensure that chp_info is up-to-date. */
562static int info_update(void)
563{
564	int rc;
565
566	mutex_lock(&info_lock);
567	rc = 0;
568	if (time_after(jiffies, chp_info_expires)) {
569		/* Data is too old, update. */
570		rc = sclp_chp_read_info(&chp_info);
571		chp_info_expires = jiffies + CHP_INFO_UPDATE_INTERVAL ;
572	}
573	mutex_unlock(&info_lock);
574
575	return rc;
576}
577
578/**
579 * chp_info_get_status - retrieve configure status of a channel-path
580 * @chpid: channel-path ID
581 *
582 * On success, return 0 for standby, 1 for configured, 2 for reserved,
583 * 3 for not recognized. Return negative error code on error.
584 */
585int chp_info_get_status(struct chp_id chpid)
586{
587	int rc;
588	int bit;
589
590	rc = info_update();
591	if (rc)
592		return rc;
593
594	bit = info_bit_num(chpid);
595	mutex_lock(&info_lock);
596	if (!chp_test_bit(chp_info.recognized, bit))
597		rc = CHP_STATUS_NOT_RECOGNIZED;
598	else if (chp_test_bit(chp_info.configured, bit))
599		rc = CHP_STATUS_CONFIGURED;
600	else if (chp_test_bit(chp_info.standby, bit))
601		rc = CHP_STATUS_STANDBY;
602	else
603		rc = CHP_STATUS_RESERVED;
604	mutex_unlock(&info_lock);
605
606	return rc;
607}
608
609/* Return configure task for chpid. */
610static enum cfg_task_t cfg_get_task(struct chp_id chpid)
611{
612	return chp_cfg_task[chpid.cssid][chpid.id];
613}
614
615/* Set configure task for chpid. */
616static void cfg_set_task(struct chp_id chpid, enum cfg_task_t cfg)
617{
618	chp_cfg_task[chpid.cssid][chpid.id] = cfg;
619}
620
621/* Perform one configure/deconfigure request. Reschedule work function until
622 * last request. */
623static void cfg_func(struct work_struct *work)
624{
625	struct chp_id chpid;
626	enum cfg_task_t t;
627	int rc;
628
629	mutex_lock(&cfg_lock);
630	t = cfg_none;
631	chp_id_for_each(&chpid) {
632		t = cfg_get_task(chpid);
633		if (t != cfg_none) {
634			cfg_set_task(chpid, cfg_none);
635			break;
636		}
637	}
638	mutex_unlock(&cfg_lock);
639
640	switch (t) {
641	case cfg_configure:
642		rc = sclp_chp_configure(chpid);
643		if (rc)
644			CIO_MSG_EVENT(2, "chp: sclp_chp_configure(%x.%02x)="
645				      "%d\n", chpid.cssid, chpid.id, rc);
646		else {
647			info_expire();
648			chsc_chp_online(chpid);
649		}
650		break;
651	case cfg_deconfigure:
652		rc = sclp_chp_deconfigure(chpid);
653		if (rc)
654			CIO_MSG_EVENT(2, "chp: sclp_chp_deconfigure(%x.%02x)="
655				      "%d\n", chpid.cssid, chpid.id, rc);
656		else {
657			info_expire();
658			chsc_chp_offline(chpid);
659		}
660		break;
661	case cfg_none:
662		/* Get updated information after last change. */
663		info_update();
664		mutex_lock(&cfg_lock);
665		cfg_busy = 0;
666		mutex_unlock(&cfg_lock);
667		wake_up_interruptible(&cfg_wait_queue);
668		return;
669	}
670	queue_work(chp_wq, &cfg_work);
671}
672
673/**
674 * chp_cfg_schedule - schedule chpid configuration request
675 * @chpid - channel-path ID
676 * @configure - Non-zero for configure, zero for deconfigure
677 *
678 * Schedule a channel-path configuration/deconfiguration request.
679 */
680void chp_cfg_schedule(struct chp_id chpid, int configure)
681{
682	CIO_MSG_EVENT(2, "chp_cfg_sched%x.%02x=%d\n", chpid.cssid, chpid.id,
683		      configure);
684	mutex_lock(&cfg_lock);
685	cfg_set_task(chpid, configure ? cfg_configure : cfg_deconfigure);
686	cfg_busy = 1;
687	mutex_unlock(&cfg_lock);
688	queue_work(chp_wq, &cfg_work);
689}
690
691/**
692 * chp_cfg_cancel_deconfigure - cancel chpid deconfiguration request
693 * @chpid - channel-path ID
694 *
695 * Cancel an active channel-path deconfiguration request if it has not yet
696 * been performed.
697 */
698void chp_cfg_cancel_deconfigure(struct chp_id chpid)
699{
700	CIO_MSG_EVENT(2, "chp_cfg_cancel:%x.%02x\n", chpid.cssid, chpid.id);
701	mutex_lock(&cfg_lock);
702	if (cfg_get_task(chpid) == cfg_deconfigure)
703		cfg_set_task(chpid, cfg_none);
704	mutex_unlock(&cfg_lock);
705}
706
707static int cfg_wait_idle(void)
708{
709	if (wait_event_interruptible(cfg_wait_queue, !cfg_busy))
710		return -ERESTARTSYS;
711	return 0;
712}
713
714static int __init chp_init(void)
715{
716	struct chp_id chpid;
717	int ret;
718
719	ret = crw_register_handler(CRW_RSC_CPATH, chp_process_crw);
720	if (ret)
721		return ret;
722	chp_wq = create_singlethread_workqueue("cio_chp");
723	if (!chp_wq) {
724		crw_unregister_handler(CRW_RSC_CPATH);
725		return -ENOMEM;
726	}
727	INIT_WORK(&cfg_work, cfg_func);
728	init_waitqueue_head(&cfg_wait_queue);
729	if (info_update())
730		return 0;
731	/* Register available channel-paths. */
732	chp_id_for_each(&chpid) {
733		if (chp_info_get_status(chpid) != CHP_STATUS_NOT_RECOGNIZED)
734			chp_new(chpid);
735	}
736
737	return 0;
738}
739
740subsys_initcall(chp_init);
741