1  // SPDX-License-Identifier: GPL-2.0
2  /*
3   * driver for channel subsystem
4   *
5   * Copyright IBM Corp. 2002, 2010
6   *
7   * Author(s): Arnd Bergmann (arndb@de.ibm.com)
8   *	      Cornelia Huck (cornelia.huck@de.ibm.com)
9   */
10  
11  #define KMSG_COMPONENT "cio"
12  #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
13  
14  #include <linux/export.h>
15  #include <linux/init.h>
16  #include <linux/device.h>
17  #include <linux/slab.h>
18  #include <linux/errno.h>
19  #include <linux/list.h>
20  #include <linux/reboot.h>
21  #include <linux/proc_fs.h>
22  #include <linux/genalloc.h>
23  #include <linux/dma-mapping.h>
24  #include <asm/isc.h>
25  #include <asm/crw.h>
26  
27  #include "css.h"
28  #include "cio.h"
29  #include "blacklist.h"
30  #include "cio_debug.h"
31  #include "ioasm.h"
32  #include "chsc.h"
33  #include "device.h"
34  #include "idset.h"
35  #include "chp.h"
36  
37  int css_init_done = 0;
38  int max_ssid;
39  
40  #define MAX_CSS_IDX 0
41  struct channel_subsystem *channel_subsystems[MAX_CSS_IDX + 1];
42  static const struct bus_type css_bus_type;
43  
44  int
for_each_subchannel(int (* fn)(struct subchannel_id,void *),void * data)45  for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
46  {
47  	struct subchannel_id schid;
48  	int ret;
49  
50  	init_subchannel_id(&schid);
51  	do {
52  		do {
53  			ret = fn(schid, data);
54  			if (ret)
55  				break;
56  		} while (schid.sch_no++ < __MAX_SUBCHANNEL);
57  		schid.sch_no = 0;
58  	} while (schid.ssid++ < max_ssid);
59  	return ret;
60  }
61  
62  struct cb_data {
63  	void *data;
64  	struct idset *set;
65  	int (*fn_known_sch)(struct subchannel *, void *);
66  	int (*fn_unknown_sch)(struct subchannel_id, void *);
67  };
68  
call_fn_known_sch(struct device * dev,void * data)69  static int call_fn_known_sch(struct device *dev, void *data)
70  {
71  	struct subchannel *sch = to_subchannel(dev);
72  	struct cb_data *cb = data;
73  	int rc = 0;
74  
75  	if (cb->set)
76  		idset_sch_del(cb->set, sch->schid);
77  	if (cb->fn_known_sch)
78  		rc = cb->fn_known_sch(sch, cb->data);
79  	return rc;
80  }
81  
call_fn_unknown_sch(struct subchannel_id schid,void * data)82  static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
83  {
84  	struct cb_data *cb = data;
85  	int rc = 0;
86  
87  	if (idset_sch_contains(cb->set, schid))
88  		rc = cb->fn_unknown_sch(schid, cb->data);
89  	return rc;
90  }
91  
call_fn_all_sch(struct subchannel_id schid,void * data)92  static int call_fn_all_sch(struct subchannel_id schid, void *data)
93  {
94  	struct cb_data *cb = data;
95  	struct subchannel *sch;
96  	int rc = 0;
97  
98  	sch = get_subchannel_by_schid(schid);
99  	if (sch) {
100  		if (cb->fn_known_sch)
101  			rc = cb->fn_known_sch(sch, cb->data);
102  		put_device(&sch->dev);
103  	} else {
104  		if (cb->fn_unknown_sch)
105  			rc = cb->fn_unknown_sch(schid, cb->data);
106  	}
107  
108  	return rc;
109  }
110  
for_each_subchannel_staged(int (* fn_known)(struct subchannel *,void *),int (* fn_unknown)(struct subchannel_id,void *),void * data)111  int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
112  			       int (*fn_unknown)(struct subchannel_id,
113  			       void *), void *data)
114  {
115  	struct cb_data cb;
116  	int rc;
117  
118  	cb.data = data;
119  	cb.fn_known_sch = fn_known;
120  	cb.fn_unknown_sch = fn_unknown;
121  
122  	if (fn_known && !fn_unknown) {
123  		/* Skip idset allocation in case of known-only loop. */
124  		cb.set = NULL;
125  		return bus_for_each_dev(&css_bus_type, NULL, &cb,
126  					call_fn_known_sch);
127  	}
128  
129  	cb.set = idset_sch_new();
130  	if (!cb.set)
131  		/* fall back to brute force scanning in case of oom */
132  		return for_each_subchannel(call_fn_all_sch, &cb);
133  
134  	idset_fill(cb.set);
135  
136  	/* Process registered subchannels. */
137  	rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
138  	if (rc)
139  		goto out;
140  	/* Process unregistered subchannels. */
141  	if (fn_unknown)
142  		rc = for_each_subchannel(call_fn_unknown_sch, &cb);
143  out:
144  	idset_free(cb.set);
145  
146  	return rc;
147  }
148  
149  static void css_sch_todo(struct work_struct *work);
150  
css_sch_create_locks(struct subchannel * sch)151  static void css_sch_create_locks(struct subchannel *sch)
152  {
153  	spin_lock_init(&sch->lock);
154  	mutex_init(&sch->reg_mutex);
155  }
156  
css_subchannel_release(struct device * dev)157  static void css_subchannel_release(struct device *dev)
158  {
159  	struct subchannel *sch = to_subchannel(dev);
160  
161  	sch->config.intparm = 0;
162  	cio_commit_config(sch);
163  	kfree(sch->driver_override);
164  	kfree(sch);
165  }
166  
css_validate_subchannel(struct subchannel_id schid,struct schib * schib)167  static int css_validate_subchannel(struct subchannel_id schid,
168  				   struct schib *schib)
169  {
170  	int err;
171  
172  	switch (schib->pmcw.st) {
173  	case SUBCHANNEL_TYPE_IO:
174  	case SUBCHANNEL_TYPE_MSG:
175  		if (!css_sch_is_valid(schib))
176  			err = -ENODEV;
177  		else if (is_blacklisted(schid.ssid, schib->pmcw.dev)) {
178  			CIO_MSG_EVENT(6, "Blacklisted device detected "
179  				      "at devno %04X, subchannel set %x\n",
180  				      schib->pmcw.dev, schid.ssid);
181  			err = -ENODEV;
182  		} else
183  			err = 0;
184  		break;
185  	default:
186  		err = 0;
187  	}
188  	if (err)
189  		goto out;
190  
191  	CIO_MSG_EVENT(4, "Subchannel 0.%x.%04x reports subchannel type %04X\n",
192  		      schid.ssid, schid.sch_no, schib->pmcw.st);
193  out:
194  	return err;
195  }
196  
css_alloc_subchannel(struct subchannel_id schid,struct schib * schib)197  struct subchannel *css_alloc_subchannel(struct subchannel_id schid,
198  					struct schib *schib)
199  {
200  	struct subchannel *sch;
201  	int ret;
202  
203  	ret = css_validate_subchannel(schid, schib);
204  	if (ret < 0)
205  		return ERR_PTR(ret);
206  
207  	sch = kzalloc(sizeof(*sch), GFP_KERNEL | GFP_DMA);
208  	if (!sch)
209  		return ERR_PTR(-ENOMEM);
210  
211  	sch->schid = schid;
212  	sch->schib = *schib;
213  	sch->st = schib->pmcw.st;
214  
215  	css_sch_create_locks(sch);
216  
217  	INIT_WORK(&sch->todo_work, css_sch_todo);
218  	sch->dev.release = &css_subchannel_release;
219  	sch->dev.dma_mask = &sch->dma_mask;
220  	device_initialize(&sch->dev);
221  	/*
222  	 * The physical addresses for some of the dma structures that can
223  	 * belong to a subchannel need to fit 31 bit width (e.g. ccw).
224  	 */
225  	ret = dma_set_coherent_mask(&sch->dev, DMA_BIT_MASK(31));
226  	if (ret)
227  		goto err;
228  	/*
229  	 * But we don't have such restrictions imposed on the stuff that
230  	 * is handled by the streaming API.
231  	 */
232  	ret = dma_set_mask(&sch->dev, DMA_BIT_MASK(64));
233  	if (ret)
234  		goto err;
235  
236  	return sch;
237  
238  err:
239  	kfree(sch);
240  	return ERR_PTR(ret);
241  }
242  
css_sch_device_register(struct subchannel * sch)243  static int css_sch_device_register(struct subchannel *sch)
244  {
245  	int ret;
246  
247  	mutex_lock(&sch->reg_mutex);
248  	dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
249  		     sch->schid.sch_no);
250  	ret = device_add(&sch->dev);
251  	mutex_unlock(&sch->reg_mutex);
252  	return ret;
253  }
254  
255  /**
256   * css_sch_device_unregister - unregister a subchannel
257   * @sch: subchannel to be unregistered
258   */
css_sch_device_unregister(struct subchannel * sch)259  void css_sch_device_unregister(struct subchannel *sch)
260  {
261  	mutex_lock(&sch->reg_mutex);
262  	if (device_is_registered(&sch->dev))
263  		device_unregister(&sch->dev);
264  	mutex_unlock(&sch->reg_mutex);
265  }
266  EXPORT_SYMBOL_GPL(css_sch_device_unregister);
267  
ssd_from_pmcw(struct chsc_ssd_info * ssd,struct pmcw * pmcw)268  static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
269  {
270  	int i;
271  	int mask;
272  
273  	memset(ssd, 0, sizeof(struct chsc_ssd_info));
274  	ssd->path_mask = pmcw->pim;
275  	for (i = 0; i < 8; i++) {
276  		mask = 0x80 >> i;
277  		if (pmcw->pim & mask) {
278  			chp_id_init(&ssd->chpid[i]);
279  			ssd->chpid[i].id = pmcw->chpid[i];
280  		}
281  	}
282  }
283  
ssd_register_chpids(struct chsc_ssd_info * ssd)284  static void ssd_register_chpids(struct chsc_ssd_info *ssd)
285  {
286  	int i;
287  	int mask;
288  
289  	for (i = 0; i < 8; i++) {
290  		mask = 0x80 >> i;
291  		if (ssd->path_mask & mask)
292  			chp_new(ssd->chpid[i]);
293  	}
294  }
295  
css_update_ssd_info(struct subchannel * sch)296  void css_update_ssd_info(struct subchannel *sch)
297  {
298  	int ret;
299  
300  	ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
301  	if (ret)
302  		ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
303  
304  	ssd_register_chpids(&sch->ssd_info);
305  }
306  
type_show(struct device * dev,struct device_attribute * attr,char * buf)307  static ssize_t type_show(struct device *dev, struct device_attribute *attr,
308  			 char *buf)
309  {
310  	struct subchannel *sch = to_subchannel(dev);
311  
312  	return sysfs_emit(buf, "%01x\n", sch->st);
313  }
314  
315  static DEVICE_ATTR_RO(type);
316  
modalias_show(struct device * dev,struct device_attribute * attr,char * buf)317  static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
318  			     char *buf)
319  {
320  	struct subchannel *sch = to_subchannel(dev);
321  
322  	return sysfs_emit(buf, "css:t%01X\n", sch->st);
323  }
324  
325  static DEVICE_ATTR_RO(modalias);
326  
driver_override_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)327  static ssize_t driver_override_store(struct device *dev,
328  				     struct device_attribute *attr,
329  				     const char *buf, size_t count)
330  {
331  	struct subchannel *sch = to_subchannel(dev);
332  	int ret;
333  
334  	ret = driver_set_override(dev, &sch->driver_override, buf, count);
335  	if (ret)
336  		return ret;
337  
338  	return count;
339  }
340  
driver_override_show(struct device * dev,struct device_attribute * attr,char * buf)341  static ssize_t driver_override_show(struct device *dev,
342  				    struct device_attribute *attr, char *buf)
343  {
344  	struct subchannel *sch = to_subchannel(dev);
345  	ssize_t len;
346  
347  	device_lock(dev);
348  	len = sysfs_emit(buf, "%s\n", sch->driver_override);
349  	device_unlock(dev);
350  	return len;
351  }
352  static DEVICE_ATTR_RW(driver_override);
353  
354  static struct attribute *subch_attrs[] = {
355  	&dev_attr_type.attr,
356  	&dev_attr_modalias.attr,
357  	&dev_attr_driver_override.attr,
358  	NULL,
359  };
360  
361  static struct attribute_group subch_attr_group = {
362  	.attrs = subch_attrs,
363  };
364  
365  static const struct attribute_group *default_subch_attr_groups[] = {
366  	&subch_attr_group,
367  	NULL,
368  };
369  
chpids_show(struct device * dev,struct device_attribute * attr,char * buf)370  static ssize_t chpids_show(struct device *dev,
371  			   struct device_attribute *attr,
372  			   char *buf)
373  {
374  	struct subchannel *sch = to_subchannel(dev);
375  	struct chsc_ssd_info *ssd = &sch->ssd_info;
376  	ssize_t ret = 0;
377  	int mask;
378  	int chp;
379  
380  	for (chp = 0; chp < 8; chp++) {
381  		mask = 0x80 >> chp;
382  		if (ssd->path_mask & mask)
383  			ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
384  		else
385  			ret += sprintf(buf + ret, "00 ");
386  	}
387  	ret += sprintf(buf + ret, "\n");
388  	return ret;
389  }
390  static DEVICE_ATTR_RO(chpids);
391  
pimpampom_show(struct device * dev,struct device_attribute * attr,char * buf)392  static ssize_t pimpampom_show(struct device *dev,
393  			      struct device_attribute *attr,
394  			      char *buf)
395  {
396  	struct subchannel *sch = to_subchannel(dev);
397  	struct pmcw *pmcw = &sch->schib.pmcw;
398  
399  	return sysfs_emit(buf, "%02x %02x %02x\n",
400  			  pmcw->pim, pmcw->pam, pmcw->pom);
401  }
402  static DEVICE_ATTR_RO(pimpampom);
403  
dev_busid_show(struct device * dev,struct device_attribute * attr,char * buf)404  static ssize_t dev_busid_show(struct device *dev,
405  			      struct device_attribute *attr,
406  			      char *buf)
407  {
408  	struct subchannel *sch = to_subchannel(dev);
409  	struct pmcw *pmcw = &sch->schib.pmcw;
410  
411  	if ((pmcw->st == SUBCHANNEL_TYPE_IO && pmcw->dnv) ||
412  	    (pmcw->st == SUBCHANNEL_TYPE_MSG && pmcw->w))
413  		return sysfs_emit(buf, "0.%x.%04x\n", sch->schid.ssid,
414  				  pmcw->dev);
415  	else
416  		return sysfs_emit(buf, "none\n");
417  }
418  static DEVICE_ATTR_RO(dev_busid);
419  
420  static struct attribute *io_subchannel_type_attrs[] = {
421  	&dev_attr_chpids.attr,
422  	&dev_attr_pimpampom.attr,
423  	&dev_attr_dev_busid.attr,
424  	NULL,
425  };
426  ATTRIBUTE_GROUPS(io_subchannel_type);
427  
428  static const struct device_type io_subchannel_type = {
429  	.groups = io_subchannel_type_groups,
430  };
431  
css_register_subchannel(struct subchannel * sch)432  int css_register_subchannel(struct subchannel *sch)
433  {
434  	int ret;
435  
436  	/* Initialize the subchannel structure */
437  	sch->dev.parent = &channel_subsystems[0]->device;
438  	sch->dev.bus = &css_bus_type;
439  	sch->dev.groups = default_subch_attr_groups;
440  
441  	if (sch->st == SUBCHANNEL_TYPE_IO)
442  		sch->dev.type = &io_subchannel_type;
443  
444  	css_update_ssd_info(sch);
445  	/* make it known to the system */
446  	ret = css_sch_device_register(sch);
447  	if (ret) {
448  		CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
449  			      sch->schid.ssid, sch->schid.sch_no, ret);
450  		return ret;
451  	}
452  	return ret;
453  }
454  
css_probe_device(struct subchannel_id schid,struct schib * schib)455  static int css_probe_device(struct subchannel_id schid, struct schib *schib)
456  {
457  	struct subchannel *sch;
458  	int ret;
459  
460  	sch = css_alloc_subchannel(schid, schib);
461  	if (IS_ERR(sch))
462  		return PTR_ERR(sch);
463  
464  	ret = css_register_subchannel(sch);
465  	if (ret)
466  		put_device(&sch->dev);
467  
468  	return ret;
469  }
470  
471  static int
check_subchannel(struct device * dev,const void * data)472  check_subchannel(struct device *dev, const void *data)
473  {
474  	struct subchannel *sch;
475  	struct subchannel_id *schid = (void *)data;
476  
477  	sch = to_subchannel(dev);
478  	return schid_equal(&sch->schid, schid);
479  }
480  
481  struct subchannel *
get_subchannel_by_schid(struct subchannel_id schid)482  get_subchannel_by_schid(struct subchannel_id schid)
483  {
484  	struct device *dev;
485  
486  	dev = bus_find_device(&css_bus_type, NULL,
487  			      &schid, check_subchannel);
488  
489  	return dev ? to_subchannel(dev) : NULL;
490  }
491  
492  /**
493   * css_sch_is_valid() - check if a subchannel is valid
494   * @schib: subchannel information block for the subchannel
495   */
css_sch_is_valid(struct schib * schib)496  int css_sch_is_valid(struct schib *schib)
497  {
498  	if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
499  		return 0;
500  	if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
501  		return 0;
502  	return 1;
503  }
504  EXPORT_SYMBOL_GPL(css_sch_is_valid);
505  
css_evaluate_new_subchannel(struct subchannel_id schid,int slow)506  static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
507  {
508  	struct schib schib;
509  	int ccode;
510  
511  	if (!slow) {
512  		/* Will be done on the slow path. */
513  		return -EAGAIN;
514  	}
515  	/*
516  	 * The first subchannel that is not-operational (ccode==3)
517  	 * indicates that there aren't any more devices available.
518  	 * If stsch gets an exception, it means the current subchannel set
519  	 * is not valid.
520  	 */
521  	ccode = stsch(schid, &schib);
522  	if (ccode)
523  		return (ccode == 3) ? -ENXIO : ccode;
524  
525  	return css_probe_device(schid, &schib);
526  }
527  
css_evaluate_known_subchannel(struct subchannel * sch,int slow)528  static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
529  {
530  	int ret = 0;
531  
532  	if (sch->driver) {
533  		if (sch->driver->sch_event)
534  			ret = sch->driver->sch_event(sch, slow);
535  		else
536  			dev_dbg(&sch->dev,
537  				"Got subchannel machine check but "
538  				"no sch_event handler provided.\n");
539  	}
540  	if (ret != 0 && ret != -EAGAIN) {
541  		CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
542  			      sch->schid.ssid, sch->schid.sch_no, ret);
543  	}
544  	return ret;
545  }
546  
css_evaluate_subchannel(struct subchannel_id schid,int slow)547  static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
548  {
549  	struct subchannel *sch;
550  	int ret;
551  
552  	sch = get_subchannel_by_schid(schid);
553  	if (sch) {
554  		ret = css_evaluate_known_subchannel(sch, slow);
555  		put_device(&sch->dev);
556  	} else
557  		ret = css_evaluate_new_subchannel(schid, slow);
558  	if (ret == -EAGAIN)
559  		css_schedule_eval(schid);
560  }
561  
562  /**
563   * css_sched_sch_todo - schedule a subchannel operation
564   * @sch: subchannel
565   * @todo: todo
566   *
567   * Schedule the operation identified by @todo to be performed on the slow path
568   * workqueue. Do nothing if another operation with higher priority is already
569   * scheduled. Needs to be called with subchannel lock held.
570   */
css_sched_sch_todo(struct subchannel * sch,enum sch_todo todo)571  void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
572  {
573  	CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
574  		      sch->schid.ssid, sch->schid.sch_no, todo);
575  	if (sch->todo >= todo)
576  		return;
577  	/* Get workqueue ref. */
578  	if (!get_device(&sch->dev))
579  		return;
580  	sch->todo = todo;
581  	if (!queue_work(cio_work_q, &sch->todo_work)) {
582  		/* Already queued, release workqueue ref. */
583  		put_device(&sch->dev);
584  	}
585  }
586  EXPORT_SYMBOL_GPL(css_sched_sch_todo);
587  
css_sch_todo(struct work_struct * work)588  static void css_sch_todo(struct work_struct *work)
589  {
590  	struct subchannel *sch;
591  	enum sch_todo todo;
592  	int ret;
593  
594  	sch = container_of(work, struct subchannel, todo_work);
595  	/* Find out todo. */
596  	spin_lock_irq(&sch->lock);
597  	todo = sch->todo;
598  	CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
599  		      sch->schid.sch_no, todo);
600  	sch->todo = SCH_TODO_NOTHING;
601  	spin_unlock_irq(&sch->lock);
602  	/* Perform todo. */
603  	switch (todo) {
604  	case SCH_TODO_NOTHING:
605  		break;
606  	case SCH_TODO_EVAL:
607  		ret = css_evaluate_known_subchannel(sch, 1);
608  		if (ret == -EAGAIN) {
609  			spin_lock_irq(&sch->lock);
610  			css_sched_sch_todo(sch, todo);
611  			spin_unlock_irq(&sch->lock);
612  		}
613  		break;
614  	case SCH_TODO_UNREG:
615  		css_sch_device_unregister(sch);
616  		break;
617  	}
618  	/* Release workqueue ref. */
619  	put_device(&sch->dev);
620  }
621  
622  static struct idset *slow_subchannel_set;
623  static DEFINE_SPINLOCK(slow_subchannel_lock);
624  static DECLARE_WAIT_QUEUE_HEAD(css_eval_wq);
625  static atomic_t css_eval_scheduled;
626  
slow_subchannel_init(void)627  static int __init slow_subchannel_init(void)
628  {
629  	atomic_set(&css_eval_scheduled, 0);
630  	slow_subchannel_set = idset_sch_new();
631  	if (!slow_subchannel_set) {
632  		CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
633  		return -ENOMEM;
634  	}
635  	return 0;
636  }
637  
slow_eval_known_fn(struct subchannel * sch,void * data)638  static int slow_eval_known_fn(struct subchannel *sch, void *data)
639  {
640  	int eval;
641  	int rc;
642  
643  	spin_lock_irq(&slow_subchannel_lock);
644  	eval = idset_sch_contains(slow_subchannel_set, sch->schid);
645  	idset_sch_del(slow_subchannel_set, sch->schid);
646  	spin_unlock_irq(&slow_subchannel_lock);
647  	if (eval) {
648  		rc = css_evaluate_known_subchannel(sch, 1);
649  		if (rc == -EAGAIN)
650  			css_schedule_eval(sch->schid);
651  		/*
652  		 * The loop might take long time for platforms with lots of
653  		 * known devices. Allow scheduling here.
654  		 */
655  		cond_resched();
656  	}
657  	return 0;
658  }
659  
slow_eval_unknown_fn(struct subchannel_id schid,void * data)660  static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
661  {
662  	int eval;
663  	int rc = 0;
664  
665  	spin_lock_irq(&slow_subchannel_lock);
666  	eval = idset_sch_contains(slow_subchannel_set, schid);
667  	idset_sch_del(slow_subchannel_set, schid);
668  	spin_unlock_irq(&slow_subchannel_lock);
669  	if (eval) {
670  		rc = css_evaluate_new_subchannel(schid, 1);
671  		switch (rc) {
672  		case -EAGAIN:
673  			css_schedule_eval(schid);
674  			rc = 0;
675  			break;
676  		case -ENXIO:
677  		case -ENOMEM:
678  		case -EIO:
679  			/* These should abort looping */
680  			spin_lock_irq(&slow_subchannel_lock);
681  			idset_sch_del_subseq(slow_subchannel_set, schid);
682  			spin_unlock_irq(&slow_subchannel_lock);
683  			break;
684  		default:
685  			rc = 0;
686  		}
687  		/* Allow scheduling here since the containing loop might
688  		 * take a while.  */
689  		cond_resched();
690  	}
691  	return rc;
692  }
693  
css_slow_path_func(struct work_struct * unused)694  static void css_slow_path_func(struct work_struct *unused)
695  {
696  	unsigned long flags;
697  
698  	CIO_TRACE_EVENT(4, "slowpath");
699  	for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
700  				   NULL);
701  	spin_lock_irqsave(&slow_subchannel_lock, flags);
702  	if (idset_is_empty(slow_subchannel_set)) {
703  		atomic_set(&css_eval_scheduled, 0);
704  		wake_up(&css_eval_wq);
705  	}
706  	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
707  }
708  
709  static DECLARE_DELAYED_WORK(slow_path_work, css_slow_path_func);
710  struct workqueue_struct *cio_work_q;
711  
css_schedule_eval(struct subchannel_id schid)712  void css_schedule_eval(struct subchannel_id schid)
713  {
714  	unsigned long flags;
715  
716  	spin_lock_irqsave(&slow_subchannel_lock, flags);
717  	idset_sch_add(slow_subchannel_set, schid);
718  	atomic_set(&css_eval_scheduled, 1);
719  	queue_delayed_work(cio_work_q, &slow_path_work, 0);
720  	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
721  }
722  
css_schedule_eval_all(void)723  void css_schedule_eval_all(void)
724  {
725  	unsigned long flags;
726  
727  	spin_lock_irqsave(&slow_subchannel_lock, flags);
728  	idset_fill(slow_subchannel_set);
729  	atomic_set(&css_eval_scheduled, 1);
730  	queue_delayed_work(cio_work_q, &slow_path_work, 0);
731  	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
732  }
733  
__unset_validpath(struct device * dev,void * data)734  static int __unset_validpath(struct device *dev, void *data)
735  {
736  	struct idset *set = data;
737  	struct subchannel *sch = to_subchannel(dev);
738  	struct pmcw *pmcw = &sch->schib.pmcw;
739  
740  	/* Here we want to make sure that we are considering only those subchannels
741  	 * which do not have an operational device attached to it. This can be found
742  	 * with the help of PAM and POM values of pmcw. OPM provides the information
743  	 * about any path which is currently vary-off, so that we should not consider.
744  	 */
745  	if (sch->st == SUBCHANNEL_TYPE_IO &&
746  	    (sch->opm & pmcw->pam & pmcw->pom))
747  		idset_sch_del(set, sch->schid);
748  
749  	return 0;
750  }
751  
__unset_online(struct device * dev,void * data)752  static int __unset_online(struct device *dev, void *data)
753  {
754  	struct idset *set = data;
755  	struct subchannel *sch = to_subchannel(dev);
756  
757  	if (sch->st == SUBCHANNEL_TYPE_IO && sch->config.ena)
758  		idset_sch_del(set, sch->schid);
759  
760  	return 0;
761  }
762  
css_schedule_eval_cond(enum css_eval_cond cond,unsigned long delay)763  void css_schedule_eval_cond(enum css_eval_cond cond, unsigned long delay)
764  {
765  	unsigned long flags;
766  	struct idset *set;
767  
768  	/* Find unregistered subchannels. */
769  	set = idset_sch_new();
770  	if (!set) {
771  		/* Fallback. */
772  		css_schedule_eval_all();
773  		return;
774  	}
775  	idset_fill(set);
776  	switch (cond) {
777  	case CSS_EVAL_NO_PATH:
778  		bus_for_each_dev(&css_bus_type, NULL, set, __unset_validpath);
779  		break;
780  	case CSS_EVAL_NOT_ONLINE:
781  		bus_for_each_dev(&css_bus_type, NULL, set, __unset_online);
782  		break;
783  	default:
784  		break;
785  	}
786  
787  	/* Apply to slow_subchannel_set. */
788  	spin_lock_irqsave(&slow_subchannel_lock, flags);
789  	idset_add_set(slow_subchannel_set, set);
790  	atomic_set(&css_eval_scheduled, 1);
791  	queue_delayed_work(cio_work_q, &slow_path_work, delay);
792  	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
793  	idset_free(set);
794  }
795  
css_wait_for_slow_path(void)796  void css_wait_for_slow_path(void)
797  {
798  	flush_workqueue(cio_work_q);
799  }
800  
801  /* Schedule reprobing of all subchannels with no valid operational path. */
css_schedule_reprobe(void)802  void css_schedule_reprobe(void)
803  {
804  	/* Schedule with a delay to allow merging of subsequent calls. */
805  	css_schedule_eval_cond(CSS_EVAL_NO_PATH, 1 * HZ);
806  }
807  EXPORT_SYMBOL_GPL(css_schedule_reprobe);
808  
809  /*
810   * Called from the machine check handler for subchannel report words.
811   */
css_process_crw(struct crw * crw0,struct crw * crw1,int overflow)812  static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
813  {
814  	struct subchannel_id mchk_schid;
815  	struct subchannel *sch;
816  
817  	if (overflow) {
818  		css_schedule_eval_all();
819  		return;
820  	}
821  	CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
822  		      "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
823  		      crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
824  		      crw0->erc, crw0->rsid);
825  	if (crw1)
826  		CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
827  			      "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
828  			      crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
829  			      crw1->anc, crw1->erc, crw1->rsid);
830  	init_subchannel_id(&mchk_schid);
831  	mchk_schid.sch_no = crw0->rsid;
832  	if (crw1)
833  		mchk_schid.ssid = (crw1->rsid >> 4) & 3;
834  
835  	if (crw0->erc == CRW_ERC_PMOD) {
836  		sch = get_subchannel_by_schid(mchk_schid);
837  		if (sch) {
838  			css_update_ssd_info(sch);
839  			put_device(&sch->dev);
840  		}
841  	}
842  	/*
843  	 * Since we are always presented with IPI in the CRW, we have to
844  	 * use stsch() to find out if the subchannel in question has come
845  	 * or gone.
846  	 */
847  	css_evaluate_subchannel(mchk_schid, 0);
848  }
849  
850  static void __init
css_generate_pgid(struct channel_subsystem * css,u32 tod_high)851  css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
852  {
853  	struct cpuid cpu_id;
854  
855  	if (css_general_characteristics.mcss) {
856  		css->global_pgid.pgid_high.ext_cssid.version = 0x80;
857  		css->global_pgid.pgid_high.ext_cssid.cssid =
858  			css->id_valid ? css->cssid : 0;
859  	} else {
860  		css->global_pgid.pgid_high.cpu_addr = stap();
861  	}
862  	get_cpu_id(&cpu_id);
863  	css->global_pgid.cpu_id = cpu_id.ident;
864  	css->global_pgid.cpu_model = cpu_id.machine;
865  	css->global_pgid.tod_high = tod_high;
866  }
867  
channel_subsystem_release(struct device * dev)868  static void channel_subsystem_release(struct device *dev)
869  {
870  	struct channel_subsystem *css = to_css(dev);
871  
872  	mutex_destroy(&css->mutex);
873  	kfree(css);
874  }
875  
real_cssid_show(struct device * dev,struct device_attribute * a,char * buf)876  static ssize_t real_cssid_show(struct device *dev, struct device_attribute *a,
877  			       char *buf)
878  {
879  	struct channel_subsystem *css = to_css(dev);
880  
881  	if (!css->id_valid)
882  		return -EINVAL;
883  
884  	return sysfs_emit(buf, "%x\n", css->cssid);
885  }
886  static DEVICE_ATTR_RO(real_cssid);
887  
rescan_store(struct device * dev,struct device_attribute * a,const char * buf,size_t count)888  static ssize_t rescan_store(struct device *dev, struct device_attribute *a,
889  			    const char *buf, size_t count)
890  {
891  	CIO_TRACE_EVENT(4, "usr-rescan");
892  
893  	css_schedule_eval_all();
894  	css_complete_work();
895  
896  	return count;
897  }
898  static DEVICE_ATTR_WO(rescan);
899  
cm_enable_show(struct device * dev,struct device_attribute * a,char * buf)900  static ssize_t cm_enable_show(struct device *dev, struct device_attribute *a,
901  			      char *buf)
902  {
903  	struct channel_subsystem *css = to_css(dev);
904  	int ret;
905  
906  	mutex_lock(&css->mutex);
907  	ret = sysfs_emit(buf, "%x\n", css->cm_enabled);
908  	mutex_unlock(&css->mutex);
909  	return ret;
910  }
911  
cm_enable_store(struct device * dev,struct device_attribute * a,const char * buf,size_t count)912  static ssize_t cm_enable_store(struct device *dev, struct device_attribute *a,
913  			       const char *buf, size_t count)
914  {
915  	struct channel_subsystem *css = to_css(dev);
916  	unsigned long val;
917  	int ret;
918  
919  	ret = kstrtoul(buf, 16, &val);
920  	if (ret)
921  		return ret;
922  	mutex_lock(&css->mutex);
923  	switch (val) {
924  	case 0:
925  		ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
926  		break;
927  	case 1:
928  		ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
929  		break;
930  	default:
931  		ret = -EINVAL;
932  	}
933  	mutex_unlock(&css->mutex);
934  	return ret < 0 ? ret : count;
935  }
936  static DEVICE_ATTR_RW(cm_enable);
937  
cm_enable_mode(struct kobject * kobj,struct attribute * attr,int index)938  static umode_t cm_enable_mode(struct kobject *kobj, struct attribute *attr,
939  			      int index)
940  {
941  	return css_chsc_characteristics.secm ? attr->mode : 0;
942  }
943  
944  static struct attribute *cssdev_attrs[] = {
945  	&dev_attr_real_cssid.attr,
946  	&dev_attr_rescan.attr,
947  	NULL,
948  };
949  
950  static struct attribute_group cssdev_attr_group = {
951  	.attrs = cssdev_attrs,
952  };
953  
954  static struct attribute *cssdev_cm_attrs[] = {
955  	&dev_attr_cm_enable.attr,
956  	NULL,
957  };
958  
959  static struct attribute_group cssdev_cm_attr_group = {
960  	.attrs = cssdev_cm_attrs,
961  	.is_visible = cm_enable_mode,
962  };
963  
964  static const struct attribute_group *cssdev_attr_groups[] = {
965  	&cssdev_attr_group,
966  	&cssdev_cm_attr_group,
967  	NULL,
968  };
969  
setup_css(int nr)970  static int __init setup_css(int nr)
971  {
972  	struct channel_subsystem *css;
973  	int ret;
974  
975  	css = kzalloc(sizeof(*css), GFP_KERNEL);
976  	if (!css)
977  		return -ENOMEM;
978  
979  	channel_subsystems[nr] = css;
980  	dev_set_name(&css->device, "css%x", nr);
981  	css->device.groups = cssdev_attr_groups;
982  	css->device.release = channel_subsystem_release;
983  	/*
984  	 * We currently allocate notifier bits with this (using
985  	 * css->device as the device argument with the DMA API)
986  	 * and are fine with 64 bit addresses.
987  	 */
988  	ret = dma_coerce_mask_and_coherent(&css->device, DMA_BIT_MASK(64));
989  	if (ret) {
990  		kfree(css);
991  		goto out_err;
992  	}
993  
994  	mutex_init(&css->mutex);
995  	ret = chsc_get_cssid_iid(nr, &css->cssid, &css->iid);
996  	if (!ret) {
997  		css->id_valid = true;
998  		pr_info("Partition identifier %01x.%01x\n", css->cssid,
999  			css->iid);
1000  	}
1001  	css_generate_pgid(css, (u32) (get_tod_clock() >> 32));
1002  
1003  	ret = device_register(&css->device);
1004  	if (ret) {
1005  		put_device(&css->device);
1006  		goto out_err;
1007  	}
1008  
1009  	css->pseudo_subchannel = kzalloc(sizeof(*css->pseudo_subchannel),
1010  					 GFP_KERNEL);
1011  	if (!css->pseudo_subchannel) {
1012  		device_unregister(&css->device);
1013  		ret = -ENOMEM;
1014  		goto out_err;
1015  	}
1016  
1017  	css->pseudo_subchannel->dev.parent = &css->device;
1018  	css->pseudo_subchannel->dev.release = css_subchannel_release;
1019  	mutex_init(&css->pseudo_subchannel->reg_mutex);
1020  	css_sch_create_locks(css->pseudo_subchannel);
1021  
1022  	dev_set_name(&css->pseudo_subchannel->dev, "defunct");
1023  	ret = device_register(&css->pseudo_subchannel->dev);
1024  	if (ret) {
1025  		put_device(&css->pseudo_subchannel->dev);
1026  		device_unregister(&css->device);
1027  		goto out_err;
1028  	}
1029  
1030  	return ret;
1031  out_err:
1032  	channel_subsystems[nr] = NULL;
1033  	return ret;
1034  }
1035  
css_reboot_event(struct notifier_block * this,unsigned long event,void * ptr)1036  static int css_reboot_event(struct notifier_block *this,
1037  			    unsigned long event,
1038  			    void *ptr)
1039  {
1040  	struct channel_subsystem *css;
1041  	int ret;
1042  
1043  	ret = NOTIFY_DONE;
1044  	for_each_css(css) {
1045  		mutex_lock(&css->mutex);
1046  		if (css->cm_enabled)
1047  			if (chsc_secm(css, 0))
1048  				ret = NOTIFY_BAD;
1049  		mutex_unlock(&css->mutex);
1050  	}
1051  
1052  	return ret;
1053  }
1054  
1055  static struct notifier_block css_reboot_notifier = {
1056  	.notifier_call = css_reboot_event,
1057  };
1058  
1059  #define  CIO_DMA_GFP (GFP_KERNEL | __GFP_ZERO)
1060  static struct gen_pool *cio_dma_pool;
1061  
1062  /* Currently cio supports only a single css */
cio_get_dma_css_dev(void)1063  struct device *cio_get_dma_css_dev(void)
1064  {
1065  	return &channel_subsystems[0]->device;
1066  }
1067  
cio_gp_dma_create(struct device * dma_dev,int nr_pages)1068  struct gen_pool *cio_gp_dma_create(struct device *dma_dev, int nr_pages)
1069  {
1070  	struct gen_pool *gp_dma;
1071  	void *cpu_addr;
1072  	dma_addr_t dma_addr;
1073  	int i;
1074  
1075  	gp_dma = gen_pool_create(3, -1);
1076  	if (!gp_dma)
1077  		return NULL;
1078  	for (i = 0; i < nr_pages; ++i) {
1079  		cpu_addr = dma_alloc_coherent(dma_dev, PAGE_SIZE, &dma_addr,
1080  					      CIO_DMA_GFP);
1081  		if (!cpu_addr)
1082  			return gp_dma;
1083  		gen_pool_add_virt(gp_dma, (unsigned long) cpu_addr,
1084  				  dma_addr, PAGE_SIZE, -1);
1085  	}
1086  	return gp_dma;
1087  }
1088  
__gp_dma_free_dma(struct gen_pool * pool,struct gen_pool_chunk * chunk,void * data)1089  static void __gp_dma_free_dma(struct gen_pool *pool,
1090  			      struct gen_pool_chunk *chunk, void *data)
1091  {
1092  	size_t chunk_size = chunk->end_addr - chunk->start_addr + 1;
1093  
1094  	dma_free_coherent((struct device *) data, chunk_size,
1095  			 (void *) chunk->start_addr,
1096  			 (dma_addr_t) chunk->phys_addr);
1097  }
1098  
cio_gp_dma_destroy(struct gen_pool * gp_dma,struct device * dma_dev)1099  void cio_gp_dma_destroy(struct gen_pool *gp_dma, struct device *dma_dev)
1100  {
1101  	if (!gp_dma)
1102  		return;
1103  	/* this is quite ugly but no better idea */
1104  	gen_pool_for_each_chunk(gp_dma, __gp_dma_free_dma, dma_dev);
1105  	gen_pool_destroy(gp_dma);
1106  }
1107  
cio_dma_pool_init(void)1108  static int cio_dma_pool_init(void)
1109  {
1110  	/* No need to free up the resources: compiled in */
1111  	cio_dma_pool = cio_gp_dma_create(cio_get_dma_css_dev(), 1);
1112  	if (!cio_dma_pool)
1113  		return -ENOMEM;
1114  	return 0;
1115  }
1116  
__cio_gp_dma_zalloc(struct gen_pool * gp_dma,struct device * dma_dev,size_t size,dma32_t * dma_handle)1117  void *__cio_gp_dma_zalloc(struct gen_pool *gp_dma, struct device *dma_dev,
1118  			  size_t size, dma32_t *dma_handle)
1119  {
1120  	dma_addr_t dma_addr;
1121  	size_t chunk_size;
1122  	void *addr;
1123  
1124  	if (!gp_dma)
1125  		return NULL;
1126  	addr = gen_pool_dma_alloc(gp_dma, size, &dma_addr);
1127  	while (!addr) {
1128  		chunk_size = round_up(size, PAGE_SIZE);
1129  		addr = dma_alloc_coherent(dma_dev, chunk_size, &dma_addr, CIO_DMA_GFP);
1130  		if (!addr)
1131  			return NULL;
1132  		gen_pool_add_virt(gp_dma, (unsigned long)addr, dma_addr, chunk_size, -1);
1133  		addr = gen_pool_dma_alloc(gp_dma, size, dma_handle ? &dma_addr : NULL);
1134  	}
1135  	if (dma_handle)
1136  		*dma_handle = (__force dma32_t)dma_addr;
1137  	return addr;
1138  }
1139  
cio_gp_dma_zalloc(struct gen_pool * gp_dma,struct device * dma_dev,size_t size)1140  void *cio_gp_dma_zalloc(struct gen_pool *gp_dma, struct device *dma_dev,
1141  			size_t size)
1142  {
1143  	return __cio_gp_dma_zalloc(gp_dma, dma_dev, size, NULL);
1144  }
1145  
cio_gp_dma_free(struct gen_pool * gp_dma,void * cpu_addr,size_t size)1146  void cio_gp_dma_free(struct gen_pool *gp_dma, void *cpu_addr, size_t size)
1147  {
1148  	if (!cpu_addr)
1149  		return;
1150  	memset(cpu_addr, 0, size);
1151  	gen_pool_free(gp_dma, (unsigned long) cpu_addr, size);
1152  }
1153  
1154  /*
1155   * Allocate dma memory from the css global pool. Intended for memory not
1156   * specific to any single device within the css. The allocated memory
1157   * is not guaranteed to be 31-bit addressable.
1158   *
1159   * Caution: Not suitable for early stuff like console.
1160   */
cio_dma_zalloc(size_t size)1161  void *cio_dma_zalloc(size_t size)
1162  {
1163  	return cio_gp_dma_zalloc(cio_dma_pool, cio_get_dma_css_dev(), size);
1164  }
1165  
cio_dma_free(void * cpu_addr,size_t size)1166  void cio_dma_free(void *cpu_addr, size_t size)
1167  {
1168  	cio_gp_dma_free(cio_dma_pool, cpu_addr, size);
1169  }
1170  
1171  /*
1172   * Now that the driver core is running, we can setup our channel subsystem.
1173   * The struct subchannel's are created during probing.
1174   */
css_bus_init(void)1175  static int __init css_bus_init(void)
1176  {
1177  	int ret, i;
1178  
1179  	ret = chsc_init();
1180  	if (ret)
1181  		return ret;
1182  
1183  	chsc_determine_css_characteristics();
1184  	/* Try to enable MSS. */
1185  	ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
1186  	if (ret)
1187  		max_ssid = 0;
1188  	else /* Success. */
1189  		max_ssid = __MAX_SSID;
1190  
1191  	ret = slow_subchannel_init();
1192  	if (ret)
1193  		goto out;
1194  
1195  	ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
1196  	if (ret)
1197  		goto out;
1198  
1199  	if ((ret = bus_register(&css_bus_type)))
1200  		goto out;
1201  
1202  	/* Setup css structure. */
1203  	for (i = 0; i <= MAX_CSS_IDX; i++) {
1204  		ret = setup_css(i);
1205  		if (ret)
1206  			goto out_unregister;
1207  	}
1208  	ret = register_reboot_notifier(&css_reboot_notifier);
1209  	if (ret)
1210  		goto out_unregister;
1211  	ret = cio_dma_pool_init();
1212  	if (ret)
1213  		goto out_unregister_rn;
1214  	airq_init();
1215  	css_init_done = 1;
1216  
1217  	/* Enable default isc for I/O subchannels. */
1218  	isc_register(IO_SCH_ISC);
1219  
1220  	return 0;
1221  out_unregister_rn:
1222  	unregister_reboot_notifier(&css_reboot_notifier);
1223  out_unregister:
1224  	while (i-- > 0) {
1225  		struct channel_subsystem *css = channel_subsystems[i];
1226  		device_unregister(&css->pseudo_subchannel->dev);
1227  		device_unregister(&css->device);
1228  	}
1229  	bus_unregister(&css_bus_type);
1230  out:
1231  	crw_unregister_handler(CRW_RSC_SCH);
1232  	idset_free(slow_subchannel_set);
1233  	chsc_init_cleanup();
1234  	pr_alert("The CSS device driver initialization failed with "
1235  		 "errno=%d\n", ret);
1236  	return ret;
1237  }
1238  
css_bus_cleanup(void)1239  static void __init css_bus_cleanup(void)
1240  {
1241  	struct channel_subsystem *css;
1242  
1243  	for_each_css(css) {
1244  		device_unregister(&css->pseudo_subchannel->dev);
1245  		device_unregister(&css->device);
1246  	}
1247  	bus_unregister(&css_bus_type);
1248  	crw_unregister_handler(CRW_RSC_SCH);
1249  	idset_free(slow_subchannel_set);
1250  	chsc_init_cleanup();
1251  	isc_unregister(IO_SCH_ISC);
1252  }
1253  
channel_subsystem_init(void)1254  static int __init channel_subsystem_init(void)
1255  {
1256  	int ret;
1257  
1258  	ret = css_bus_init();
1259  	if (ret)
1260  		return ret;
1261  	cio_work_q = create_singlethread_workqueue("cio");
1262  	if (!cio_work_q) {
1263  		ret = -ENOMEM;
1264  		goto out_bus;
1265  	}
1266  	ret = io_subchannel_init();
1267  	if (ret)
1268  		goto out_wq;
1269  
1270  	/* Register subchannels which are already in use. */
1271  	cio_register_early_subchannels();
1272  	/* Start initial subchannel evaluation. */
1273  	css_schedule_eval_all();
1274  
1275  	return ret;
1276  out_wq:
1277  	destroy_workqueue(cio_work_q);
1278  out_bus:
1279  	css_bus_cleanup();
1280  	return ret;
1281  }
1282  subsys_initcall(channel_subsystem_init);
1283  
css_settle(struct device_driver * drv,void * unused)1284  static int css_settle(struct device_driver *drv, void *unused)
1285  {
1286  	struct css_driver *cssdrv = to_cssdriver(drv);
1287  
1288  	if (cssdrv->settle)
1289  		return cssdrv->settle();
1290  	return 0;
1291  }
1292  
css_complete_work(void)1293  int css_complete_work(void)
1294  {
1295  	int ret;
1296  
1297  	/* Wait for the evaluation of subchannels to finish. */
1298  	ret = wait_event_interruptible(css_eval_wq,
1299  				       atomic_read(&css_eval_scheduled) == 0);
1300  	if (ret)
1301  		return -EINTR;
1302  	flush_workqueue(cio_work_q);
1303  	/* Wait for the subchannel type specific initialization to finish */
1304  	return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1305  }
1306  
1307  
1308  /*
1309   * Wait for the initialization of devices to finish, to make sure we are
1310   * done with our setup if the search for the root device starts.
1311   */
channel_subsystem_init_sync(void)1312  static int __init channel_subsystem_init_sync(void)
1313  {
1314  	css_complete_work();
1315  	return 0;
1316  }
1317  subsys_initcall_sync(channel_subsystem_init_sync);
1318  
1319  #ifdef CONFIG_PROC_FS
cio_settle_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)1320  static ssize_t cio_settle_write(struct file *file, const char __user *buf,
1321  				size_t count, loff_t *ppos)
1322  {
1323  	int ret;
1324  
1325  	/* Handle pending CRW's. */
1326  	crw_wait_for_channel_report();
1327  	ret = css_complete_work();
1328  
1329  	return ret ? ret : count;
1330  }
1331  
1332  static const struct proc_ops cio_settle_proc_ops = {
1333  	.proc_open	= nonseekable_open,
1334  	.proc_write	= cio_settle_write,
1335  };
1336  
cio_settle_init(void)1337  static int __init cio_settle_init(void)
1338  {
1339  	struct proc_dir_entry *entry;
1340  
1341  	entry = proc_create("cio_settle", S_IWUSR, NULL, &cio_settle_proc_ops);
1342  	if (!entry)
1343  		return -ENOMEM;
1344  	return 0;
1345  }
1346  device_initcall(cio_settle_init);
1347  #endif /*CONFIG_PROC_FS*/
1348  
sch_is_pseudo_sch(struct subchannel * sch)1349  int sch_is_pseudo_sch(struct subchannel *sch)
1350  {
1351  	if (!sch->dev.parent)
1352  		return 0;
1353  	return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1354  }
1355  
css_bus_match(struct device * dev,const struct device_driver * drv)1356  static int css_bus_match(struct device *dev, const struct device_driver *drv)
1357  {
1358  	struct subchannel *sch = to_subchannel(dev);
1359  	const struct css_driver *driver = to_cssdriver(drv);
1360  	struct css_device_id *id;
1361  
1362  	/* When driver_override is set, only bind to the matching driver */
1363  	if (sch->driver_override && strcmp(sch->driver_override, drv->name))
1364  		return 0;
1365  
1366  	for (id = driver->subchannel_type; id->match_flags; id++) {
1367  		if (sch->st == id->type)
1368  			return 1;
1369  	}
1370  
1371  	return 0;
1372  }
1373  
css_probe(struct device * dev)1374  static int css_probe(struct device *dev)
1375  {
1376  	struct subchannel *sch;
1377  	int ret;
1378  
1379  	sch = to_subchannel(dev);
1380  	sch->driver = to_cssdriver(dev->driver);
1381  	ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1382  	if (ret)
1383  		sch->driver = NULL;
1384  	return ret;
1385  }
1386  
css_remove(struct device * dev)1387  static void css_remove(struct device *dev)
1388  {
1389  	struct subchannel *sch;
1390  
1391  	sch = to_subchannel(dev);
1392  	if (sch->driver->remove)
1393  		sch->driver->remove(sch);
1394  	sch->driver = NULL;
1395  }
1396  
css_shutdown(struct device * dev)1397  static void css_shutdown(struct device *dev)
1398  {
1399  	struct subchannel *sch;
1400  
1401  	sch = to_subchannel(dev);
1402  	if (sch->driver && sch->driver->shutdown)
1403  		sch->driver->shutdown(sch);
1404  }
1405  
css_uevent(const struct device * dev,struct kobj_uevent_env * env)1406  static int css_uevent(const struct device *dev, struct kobj_uevent_env *env)
1407  {
1408  	const struct subchannel *sch = to_subchannel(dev);
1409  	int ret;
1410  
1411  	ret = add_uevent_var(env, "ST=%01X", sch->st);
1412  	if (ret)
1413  		return ret;
1414  	ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1415  	return ret;
1416  }
1417  
1418  static const struct bus_type css_bus_type = {
1419  	.name     = "css",
1420  	.match    = css_bus_match,
1421  	.probe    = css_probe,
1422  	.remove   = css_remove,
1423  	.shutdown = css_shutdown,
1424  	.uevent   = css_uevent,
1425  };
1426  
1427  /**
1428   * css_driver_register - register a css driver
1429   * @cdrv: css driver to register
1430   *
1431   * This is mainly a wrapper around driver_register that sets name
1432   * and bus_type in the embedded struct device_driver correctly.
1433   */
css_driver_register(struct css_driver * cdrv)1434  int css_driver_register(struct css_driver *cdrv)
1435  {
1436  	cdrv->drv.bus = &css_bus_type;
1437  	return driver_register(&cdrv->drv);
1438  }
1439  EXPORT_SYMBOL_GPL(css_driver_register);
1440  
1441  /**
1442   * css_driver_unregister - unregister a css driver
1443   * @cdrv: css driver to unregister
1444   *
1445   * This is a wrapper around driver_unregister.
1446   */
css_driver_unregister(struct css_driver * cdrv)1447  void css_driver_unregister(struct css_driver *cdrv)
1448  {
1449  	driver_unregister(&cdrv->drv);
1450  }
1451  EXPORT_SYMBOL_GPL(css_driver_unregister);
1452