xref: /openbmc/linux/drivers/s390/cio/device_ops.c (revision 2359ccdd)
1 // SPDX-License-Identifier: GPL-1.0+
2 /*
3  * Copyright IBM Corp. 2002, 2009
4  *
5  * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
6  *	      Cornelia Huck (cornelia.huck@de.ibm.com)
7  */
8 #include <linux/export.h>
9 #include <linux/init.h>
10 #include <linux/errno.h>
11 #include <linux/slab.h>
12 #include <linux/list.h>
13 #include <linux/device.h>
14 #include <linux/delay.h>
15 #include <linux/completion.h>
16 
17 #include <asm/ccwdev.h>
18 #include <asm/idals.h>
19 #include <asm/chpid.h>
20 #include <asm/fcx.h>
21 
22 #include "cio.h"
23 #include "cio_debug.h"
24 #include "css.h"
25 #include "chsc.h"
26 #include "device.h"
27 #include "chp.h"
28 
29 /**
30  * ccw_device_set_options_mask() - set some options and unset the rest
31  * @cdev: device for which the options are to be set
32  * @flags: options to be set
33  *
34  * All flags specified in @flags are set, all flags not specified in @flags
35  * are cleared.
36  * Returns:
37  *   %0 on success, -%EINVAL on an invalid flag combination.
38  */
39 int ccw_device_set_options_mask(struct ccw_device *cdev, unsigned long flags)
40 {
41        /*
42 	* The flag usage is mutal exclusive ...
43 	*/
44 	if ((flags & CCWDEV_EARLY_NOTIFICATION) &&
45 	    (flags & CCWDEV_REPORT_ALL))
46 		return -EINVAL;
47 	cdev->private->options.fast = (flags & CCWDEV_EARLY_NOTIFICATION) != 0;
48 	cdev->private->options.repall = (flags & CCWDEV_REPORT_ALL) != 0;
49 	cdev->private->options.pgroup = (flags & CCWDEV_DO_PATHGROUP) != 0;
50 	cdev->private->options.force = (flags & CCWDEV_ALLOW_FORCE) != 0;
51 	cdev->private->options.mpath = (flags & CCWDEV_DO_MULTIPATH) != 0;
52 	return 0;
53 }
54 
55 /**
56  * ccw_device_set_options() - set some options
57  * @cdev: device for which the options are to be set
58  * @flags: options to be set
59  *
60  * All flags specified in @flags are set, the remainder is left untouched.
61  * Returns:
62  *   %0 on success, -%EINVAL if an invalid flag combination would ensue.
63  */
64 int ccw_device_set_options(struct ccw_device *cdev, unsigned long flags)
65 {
66        /*
67 	* The flag usage is mutal exclusive ...
68 	*/
69 	if (((flags & CCWDEV_EARLY_NOTIFICATION) &&
70 	    (flags & CCWDEV_REPORT_ALL)) ||
71 	    ((flags & CCWDEV_EARLY_NOTIFICATION) &&
72 	     cdev->private->options.repall) ||
73 	    ((flags & CCWDEV_REPORT_ALL) &&
74 	     cdev->private->options.fast))
75 		return -EINVAL;
76 	cdev->private->options.fast |= (flags & CCWDEV_EARLY_NOTIFICATION) != 0;
77 	cdev->private->options.repall |= (flags & CCWDEV_REPORT_ALL) != 0;
78 	cdev->private->options.pgroup |= (flags & CCWDEV_DO_PATHGROUP) != 0;
79 	cdev->private->options.force |= (flags & CCWDEV_ALLOW_FORCE) != 0;
80 	cdev->private->options.mpath |= (flags & CCWDEV_DO_MULTIPATH) != 0;
81 	return 0;
82 }
83 
84 /**
85  * ccw_device_clear_options() - clear some options
86  * @cdev: device for which the options are to be cleared
87  * @flags: options to be cleared
88  *
89  * All flags specified in @flags are cleared, the remainder is left untouched.
90  */
91 void ccw_device_clear_options(struct ccw_device *cdev, unsigned long flags)
92 {
93 	cdev->private->options.fast &= (flags & CCWDEV_EARLY_NOTIFICATION) == 0;
94 	cdev->private->options.repall &= (flags & CCWDEV_REPORT_ALL) == 0;
95 	cdev->private->options.pgroup &= (flags & CCWDEV_DO_PATHGROUP) == 0;
96 	cdev->private->options.force &= (flags & CCWDEV_ALLOW_FORCE) == 0;
97 	cdev->private->options.mpath &= (flags & CCWDEV_DO_MULTIPATH) == 0;
98 }
99 
100 /**
101  * ccw_device_is_pathgroup() - determine if paths to this device are grouped
102  * @cdev: ccw device
103  *
104  * Return non-zero if there is a path group, zero otherwise.
105  */
106 int ccw_device_is_pathgroup(struct ccw_device *cdev)
107 {
108 	return cdev->private->flags.pgroup;
109 }
110 EXPORT_SYMBOL(ccw_device_is_pathgroup);
111 
112 /**
113  * ccw_device_is_multipath() - determine if device is operating in multipath mode
114  * @cdev: ccw device
115  *
116  * Return non-zero if device is operating in multipath mode, zero otherwise.
117  */
118 int ccw_device_is_multipath(struct ccw_device *cdev)
119 {
120 	return cdev->private->flags.mpath;
121 }
122 EXPORT_SYMBOL(ccw_device_is_multipath);
123 
124 /**
125  * ccw_device_clear() - terminate I/O request processing
126  * @cdev: target ccw device
127  * @intparm: interruption parameter; value is only used if no I/O is
128  *	     outstanding, otherwise the intparm associated with the I/O request
129  *	     is returned
130  *
131  * ccw_device_clear() calls csch on @cdev's subchannel.
132  * Returns:
133  *  %0 on success,
134  *  -%ENODEV on device not operational,
135  *  -%EINVAL on invalid device state.
136  * Context:
137  *  Interrupts disabled, ccw device lock held
138  */
139 int ccw_device_clear(struct ccw_device *cdev, unsigned long intparm)
140 {
141 	struct subchannel *sch;
142 	int ret;
143 
144 	if (!cdev || !cdev->dev.parent)
145 		return -ENODEV;
146 	sch = to_subchannel(cdev->dev.parent);
147 	if (!sch->schib.pmcw.ena)
148 		return -EINVAL;
149 	if (cdev->private->state == DEV_STATE_NOT_OPER)
150 		return -ENODEV;
151 	if (cdev->private->state != DEV_STATE_ONLINE &&
152 	    cdev->private->state != DEV_STATE_W4SENSE)
153 		return -EINVAL;
154 
155 	ret = cio_clear(sch);
156 	if (ret == 0)
157 		cdev->private->intparm = intparm;
158 	return ret;
159 }
160 
161 /**
162  * ccw_device_start_timeout_key() - start a s390 channel program with timeout and key
163  * @cdev: target ccw device
164  * @cpa: logical start address of channel program
165  * @intparm: user specific interruption parameter; will be presented back to
166  *	     @cdev's interrupt handler. Allows a device driver to associate
167  *	     the interrupt with a particular I/O request.
168  * @lpm: defines the channel path to be used for a specific I/O request. A
169  *	 value of 0 will make cio use the opm.
170  * @key: storage key to be used for the I/O
171  * @flags: additional flags; defines the action to be performed for I/O
172  *	   processing.
173  * @expires: timeout value in jiffies
174  *
175  * Start a S/390 channel program. When the interrupt arrives, the
176  * IRQ handler is called, either immediately, delayed (dev-end missing,
177  * or sense required) or never (no IRQ handler registered).
178  * This function notifies the device driver if the channel program has not
179  * completed during the time specified by @expires. If a timeout occurs, the
180  * channel program is terminated via xsch, hsch or csch, and the device's
181  * interrupt handler will be called with an irb containing ERR_PTR(-%ETIMEDOUT).
182  * Returns:
183  *  %0, if the operation was successful;
184  *  -%EBUSY, if the device is busy, or status pending;
185  *  -%EACCES, if no path specified in @lpm is operational;
186  *  -%ENODEV, if the device is not operational.
187  * Context:
188  *  Interrupts disabled, ccw device lock held
189  */
190 int ccw_device_start_timeout_key(struct ccw_device *cdev, struct ccw1 *cpa,
191 				 unsigned long intparm, __u8 lpm, __u8 key,
192 				 unsigned long flags, int expires)
193 {
194 	struct subchannel *sch;
195 	int ret;
196 
197 	if (!cdev || !cdev->dev.parent)
198 		return -ENODEV;
199 	sch = to_subchannel(cdev->dev.parent);
200 	if (!sch->schib.pmcw.ena)
201 		return -EINVAL;
202 	if (cdev->private->state == DEV_STATE_NOT_OPER)
203 		return -ENODEV;
204 	if (cdev->private->state == DEV_STATE_VERIFY) {
205 		/* Remember to fake irb when finished. */
206 		if (!cdev->private->flags.fake_irb) {
207 			cdev->private->flags.fake_irb = FAKE_CMD_IRB;
208 			cdev->private->intparm = intparm;
209 			return 0;
210 		} else
211 			/* There's already a fake I/O around. */
212 			return -EBUSY;
213 	}
214 	if (cdev->private->state != DEV_STATE_ONLINE ||
215 	    ((sch->schib.scsw.cmd.stctl & SCSW_STCTL_PRIM_STATUS) &&
216 	     !(sch->schib.scsw.cmd.stctl & SCSW_STCTL_SEC_STATUS)) ||
217 	    cdev->private->flags.doverify)
218 		return -EBUSY;
219 	ret = cio_set_options (sch, flags);
220 	if (ret)
221 		return ret;
222 	/* Adjust requested path mask to exclude unusable paths. */
223 	if (lpm) {
224 		lpm &= sch->lpm;
225 		if (lpm == 0)
226 			return -EACCES;
227 	}
228 	ret = cio_start_key (sch, cpa, lpm, key);
229 	switch (ret) {
230 	case 0:
231 		cdev->private->intparm = intparm;
232 		if (expires)
233 			ccw_device_set_timeout(cdev, expires);
234 		break;
235 	case -EACCES:
236 	case -ENODEV:
237 		dev_fsm_event(cdev, DEV_EVENT_VERIFY);
238 		break;
239 	}
240 	return ret;
241 }
242 
243 /**
244  * ccw_device_start_key() - start a s390 channel program with key
245  * @cdev: target ccw device
246  * @cpa: logical start address of channel program
247  * @intparm: user specific interruption parameter; will be presented back to
248  *	     @cdev's interrupt handler. Allows a device driver to associate
249  *	     the interrupt with a particular I/O request.
250  * @lpm: defines the channel path to be used for a specific I/O request. A
251  *	 value of 0 will make cio use the opm.
252  * @key: storage key to be used for the I/O
253  * @flags: additional flags; defines the action to be performed for I/O
254  *	   processing.
255  *
256  * Start a S/390 channel program. When the interrupt arrives, the
257  * IRQ handler is called, either immediately, delayed (dev-end missing,
258  * or sense required) or never (no IRQ handler registered).
259  * Returns:
260  *  %0, if the operation was successful;
261  *  -%EBUSY, if the device is busy, or status pending;
262  *  -%EACCES, if no path specified in @lpm is operational;
263  *  -%ENODEV, if the device is not operational.
264  * Context:
265  *  Interrupts disabled, ccw device lock held
266  */
267 int ccw_device_start_key(struct ccw_device *cdev, struct ccw1 *cpa,
268 			 unsigned long intparm, __u8 lpm, __u8 key,
269 			 unsigned long flags)
270 {
271 	return ccw_device_start_timeout_key(cdev, cpa, intparm, lpm, key,
272 					    flags, 0);
273 }
274 
275 /**
276  * ccw_device_start() - start a s390 channel program
277  * @cdev: target ccw device
278  * @cpa: logical start address of channel program
279  * @intparm: user specific interruption parameter; will be presented back to
280  *	     @cdev's interrupt handler. Allows a device driver to associate
281  *	     the interrupt with a particular I/O request.
282  * @lpm: defines the channel path to be used for a specific I/O request. A
283  *	 value of 0 will make cio use the opm.
284  * @flags: additional flags; defines the action to be performed for I/O
285  *	   processing.
286  *
287  * Start a S/390 channel program. When the interrupt arrives, the
288  * IRQ handler is called, either immediately, delayed (dev-end missing,
289  * or sense required) or never (no IRQ handler registered).
290  * Returns:
291  *  %0, if the operation was successful;
292  *  -%EBUSY, if the device is busy, or status pending;
293  *  -%EACCES, if no path specified in @lpm is operational;
294  *  -%ENODEV, if the device is not operational.
295  * Context:
296  *  Interrupts disabled, ccw device lock held
297  */
298 int ccw_device_start(struct ccw_device *cdev, struct ccw1 *cpa,
299 		     unsigned long intparm, __u8 lpm, unsigned long flags)
300 {
301 	return ccw_device_start_key(cdev, cpa, intparm, lpm,
302 				    PAGE_DEFAULT_KEY, flags);
303 }
304 
305 /**
306  * ccw_device_start_timeout() - start a s390 channel program with timeout
307  * @cdev: target ccw device
308  * @cpa: logical start address of channel program
309  * @intparm: user specific interruption parameter; will be presented back to
310  *	     @cdev's interrupt handler. Allows a device driver to associate
311  *	     the interrupt with a particular I/O request.
312  * @lpm: defines the channel path to be used for a specific I/O request. A
313  *	 value of 0 will make cio use the opm.
314  * @flags: additional flags; defines the action to be performed for I/O
315  *	   processing.
316  * @expires: timeout value in jiffies
317  *
318  * Start a S/390 channel program. When the interrupt arrives, the
319  * IRQ handler is called, either immediately, delayed (dev-end missing,
320  * or sense required) or never (no IRQ handler registered).
321  * This function notifies the device driver if the channel program has not
322  * completed during the time specified by @expires. If a timeout occurs, the
323  * channel program is terminated via xsch, hsch or csch, and the device's
324  * interrupt handler will be called with an irb containing ERR_PTR(-%ETIMEDOUT).
325  * Returns:
326  *  %0, if the operation was successful;
327  *  -%EBUSY, if the device is busy, or status pending;
328  *  -%EACCES, if no path specified in @lpm is operational;
329  *  -%ENODEV, if the device is not operational.
330  * Context:
331  *  Interrupts disabled, ccw device lock held
332  */
333 int ccw_device_start_timeout(struct ccw_device *cdev, struct ccw1 *cpa,
334 			     unsigned long intparm, __u8 lpm,
335 			     unsigned long flags, int expires)
336 {
337 	return ccw_device_start_timeout_key(cdev, cpa, intparm, lpm,
338 					    PAGE_DEFAULT_KEY, flags,
339 					    expires);
340 }
341 
342 
343 /**
344  * ccw_device_halt() - halt I/O request processing
345  * @cdev: target ccw device
346  * @intparm: interruption parameter; value is only used if no I/O is
347  *	     outstanding, otherwise the intparm associated with the I/O request
348  *	     is returned
349  *
350  * ccw_device_halt() calls hsch on @cdev's subchannel.
351  * Returns:
352  *  %0 on success,
353  *  -%ENODEV on device not operational,
354  *  -%EINVAL on invalid device state,
355  *  -%EBUSY on device busy or interrupt pending.
356  * Context:
357  *  Interrupts disabled, ccw device lock held
358  */
359 int ccw_device_halt(struct ccw_device *cdev, unsigned long intparm)
360 {
361 	struct subchannel *sch;
362 	int ret;
363 
364 	if (!cdev || !cdev->dev.parent)
365 		return -ENODEV;
366 	sch = to_subchannel(cdev->dev.parent);
367 	if (!sch->schib.pmcw.ena)
368 		return -EINVAL;
369 	if (cdev->private->state == DEV_STATE_NOT_OPER)
370 		return -ENODEV;
371 	if (cdev->private->state != DEV_STATE_ONLINE &&
372 	    cdev->private->state != DEV_STATE_W4SENSE)
373 		return -EINVAL;
374 
375 	ret = cio_halt(sch);
376 	if (ret == 0)
377 		cdev->private->intparm = intparm;
378 	return ret;
379 }
380 
381 /**
382  * ccw_device_resume() - resume channel program execution
383  * @cdev: target ccw device
384  *
385  * ccw_device_resume() calls rsch on @cdev's subchannel.
386  * Returns:
387  *  %0 on success,
388  *  -%ENODEV on device not operational,
389  *  -%EINVAL on invalid device state,
390  *  -%EBUSY on device busy or interrupt pending.
391  * Context:
392  *  Interrupts disabled, ccw device lock held
393  */
394 int ccw_device_resume(struct ccw_device *cdev)
395 {
396 	struct subchannel *sch;
397 
398 	if (!cdev || !cdev->dev.parent)
399 		return -ENODEV;
400 	sch = to_subchannel(cdev->dev.parent);
401 	if (!sch->schib.pmcw.ena)
402 		return -EINVAL;
403 	if (cdev->private->state == DEV_STATE_NOT_OPER)
404 		return -ENODEV;
405 	if (cdev->private->state != DEV_STATE_ONLINE ||
406 	    !(sch->schib.scsw.cmd.actl & SCSW_ACTL_SUSPENDED))
407 		return -EINVAL;
408 	return cio_resume(sch);
409 }
410 
411 /**
412  * ccw_device_get_ciw() - Search for CIW command in extended sense data.
413  * @cdev: ccw device to inspect
414  * @ct: command type to look for
415  *
416  * During SenseID, command information words (CIWs) describing special
417  * commands available to the device may have been stored in the extended
418  * sense data. This function searches for CIWs of a specified command
419  * type in the extended sense data.
420  * Returns:
421  *  %NULL if no extended sense data has been stored or if no CIW of the
422  *  specified command type could be found,
423  *  else a pointer to the CIW of the specified command type.
424  */
425 struct ciw *ccw_device_get_ciw(struct ccw_device *cdev, __u32 ct)
426 {
427 	int ciw_cnt;
428 
429 	if (cdev->private->flags.esid == 0)
430 		return NULL;
431 	for (ciw_cnt = 0; ciw_cnt < MAX_CIWS; ciw_cnt++)
432 		if (cdev->private->senseid.ciw[ciw_cnt].ct == ct)
433 			return cdev->private->senseid.ciw + ciw_cnt;
434 	return NULL;
435 }
436 
437 /**
438  * ccw_device_get_path_mask() - get currently available paths
439  * @cdev: ccw device to be queried
440  * Returns:
441  *  %0 if no subchannel for the device is available,
442  *  else the mask of currently available paths for the ccw device's subchannel.
443  */
444 __u8 ccw_device_get_path_mask(struct ccw_device *cdev)
445 {
446 	struct subchannel *sch;
447 
448 	if (!cdev->dev.parent)
449 		return 0;
450 
451 	sch = to_subchannel(cdev->dev.parent);
452 	return sch->lpm;
453 }
454 
455 /**
456  * ccw_device_get_chp_desc() - return newly allocated channel-path descriptor
457  * @cdev: device to obtain the descriptor for
458  * @chp_idx: index of the channel path
459  *
460  * On success return a newly allocated copy of the channel-path description
461  * data associated with the given channel path. Return %NULL on error.
462  */
463 struct channel_path_desc_fmt0 *ccw_device_get_chp_desc(struct ccw_device *cdev,
464 						       int chp_idx)
465 {
466 	struct subchannel *sch;
467 	struct chp_id chpid;
468 
469 	sch = to_subchannel(cdev->dev.parent);
470 	chp_id_init(&chpid);
471 	chpid.id = sch->schib.pmcw.chpid[chp_idx];
472 	return chp_get_chp_desc(chpid);
473 }
474 
475 /**
476  * ccw_device_get_id() - obtain a ccw device id
477  * @cdev: device to obtain the id for
478  * @dev_id: where to fill in the values
479  */
480 void ccw_device_get_id(struct ccw_device *cdev, struct ccw_dev_id *dev_id)
481 {
482 	*dev_id = cdev->private->dev_id;
483 }
484 EXPORT_SYMBOL(ccw_device_get_id);
485 
486 /**
487  * ccw_device_tm_start_timeout_key() - perform start function
488  * @cdev: ccw device on which to perform the start function
489  * @tcw: transport-command word to be started
490  * @intparm: user defined parameter to be passed to the interrupt handler
491  * @lpm: mask of paths to use
492  * @key: storage key to use for storage access
493  * @expires: time span in jiffies after which to abort request
494  *
495  * Start the tcw on the given ccw device. Return zero on success, non-zero
496  * otherwise.
497  */
498 int ccw_device_tm_start_timeout_key(struct ccw_device *cdev, struct tcw *tcw,
499 				    unsigned long intparm, u8 lpm, u8 key,
500 				    int expires)
501 {
502 	struct subchannel *sch;
503 	int rc;
504 
505 	sch = to_subchannel(cdev->dev.parent);
506 	if (!sch->schib.pmcw.ena)
507 		return -EINVAL;
508 	if (cdev->private->state == DEV_STATE_VERIFY) {
509 		/* Remember to fake irb when finished. */
510 		if (!cdev->private->flags.fake_irb) {
511 			cdev->private->flags.fake_irb = FAKE_TM_IRB;
512 			cdev->private->intparm = intparm;
513 			return 0;
514 		} else
515 			/* There's already a fake I/O around. */
516 			return -EBUSY;
517 	}
518 	if (cdev->private->state != DEV_STATE_ONLINE)
519 		return -EIO;
520 	/* Adjust requested path mask to exclude unusable paths. */
521 	if (lpm) {
522 		lpm &= sch->lpm;
523 		if (lpm == 0)
524 			return -EACCES;
525 	}
526 	rc = cio_tm_start_key(sch, tcw, lpm, key);
527 	if (rc == 0) {
528 		cdev->private->intparm = intparm;
529 		if (expires)
530 			ccw_device_set_timeout(cdev, expires);
531 	}
532 	return rc;
533 }
534 EXPORT_SYMBOL(ccw_device_tm_start_timeout_key);
535 
536 /**
537  * ccw_device_tm_start_key() - perform start function
538  * @cdev: ccw device on which to perform the start function
539  * @tcw: transport-command word to be started
540  * @intparm: user defined parameter to be passed to the interrupt handler
541  * @lpm: mask of paths to use
542  * @key: storage key to use for storage access
543  *
544  * Start the tcw on the given ccw device. Return zero on success, non-zero
545  * otherwise.
546  */
547 int ccw_device_tm_start_key(struct ccw_device *cdev, struct tcw *tcw,
548 			    unsigned long intparm, u8 lpm, u8 key)
549 {
550 	return ccw_device_tm_start_timeout_key(cdev, tcw, intparm, lpm, key, 0);
551 }
552 EXPORT_SYMBOL(ccw_device_tm_start_key);
553 
554 /**
555  * ccw_device_tm_start() - perform start function
556  * @cdev: ccw device on which to perform the start function
557  * @tcw: transport-command word to be started
558  * @intparm: user defined parameter to be passed to the interrupt handler
559  * @lpm: mask of paths to use
560  *
561  * Start the tcw on the given ccw device. Return zero on success, non-zero
562  * otherwise.
563  */
564 int ccw_device_tm_start(struct ccw_device *cdev, struct tcw *tcw,
565 			unsigned long intparm, u8 lpm)
566 {
567 	return ccw_device_tm_start_key(cdev, tcw, intparm, lpm,
568 				       PAGE_DEFAULT_KEY);
569 }
570 EXPORT_SYMBOL(ccw_device_tm_start);
571 
572 /**
573  * ccw_device_tm_start_timeout() - perform start function
574  * @cdev: ccw device on which to perform the start function
575  * @tcw: transport-command word to be started
576  * @intparm: user defined parameter to be passed to the interrupt handler
577  * @lpm: mask of paths to use
578  * @expires: time span in jiffies after which to abort request
579  *
580  * Start the tcw on the given ccw device. Return zero on success, non-zero
581  * otherwise.
582  */
583 int ccw_device_tm_start_timeout(struct ccw_device *cdev, struct tcw *tcw,
584 			       unsigned long intparm, u8 lpm, int expires)
585 {
586 	return ccw_device_tm_start_timeout_key(cdev, tcw, intparm, lpm,
587 					       PAGE_DEFAULT_KEY, expires);
588 }
589 EXPORT_SYMBOL(ccw_device_tm_start_timeout);
590 
591 /**
592  * ccw_device_get_mdc() - accumulate max data count
593  * @cdev: ccw device for which the max data count is accumulated
594  * @mask: mask of paths to use
595  *
596  * Return the number of 64K-bytes blocks all paths at least support
597  * for a transport command. Return values <= 0 indicate failures.
598  */
599 int ccw_device_get_mdc(struct ccw_device *cdev, u8 mask)
600 {
601 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
602 	struct channel_path *chp;
603 	struct chp_id chpid;
604 	int mdc = 0, i;
605 
606 	/* Adjust requested path mask to excluded varied off paths. */
607 	if (mask)
608 		mask &= sch->lpm;
609 	else
610 		mask = sch->lpm;
611 
612 	chp_id_init(&chpid);
613 	for (i = 0; i < 8; i++) {
614 		if (!(mask & (0x80 >> i)))
615 			continue;
616 		chpid.id = sch->schib.pmcw.chpid[i];
617 		chp = chpid_to_chp(chpid);
618 		if (!chp)
619 			continue;
620 
621 		mutex_lock(&chp->lock);
622 		if (!chp->desc_fmt1.f) {
623 			mutex_unlock(&chp->lock);
624 			return 0;
625 		}
626 		if (!chp->desc_fmt1.r)
627 			mdc = 1;
628 		mdc = mdc ? min_t(int, mdc, chp->desc_fmt1.mdc) :
629 			    chp->desc_fmt1.mdc;
630 		mutex_unlock(&chp->lock);
631 	}
632 
633 	return mdc;
634 }
635 EXPORT_SYMBOL(ccw_device_get_mdc);
636 
637 /**
638  * ccw_device_tm_intrg() - perform interrogate function
639  * @cdev: ccw device on which to perform the interrogate function
640  *
641  * Perform an interrogate function on the given ccw device. Return zero on
642  * success, non-zero otherwise.
643  */
644 int ccw_device_tm_intrg(struct ccw_device *cdev)
645 {
646 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
647 
648 	if (!sch->schib.pmcw.ena)
649 		return -EINVAL;
650 	if (cdev->private->state != DEV_STATE_ONLINE)
651 		return -EIO;
652 	if (!scsw_is_tm(&sch->schib.scsw) ||
653 	    !(scsw_actl(&sch->schib.scsw) & SCSW_ACTL_START_PEND))
654 		return -EINVAL;
655 	return cio_tm_intrg(sch);
656 }
657 EXPORT_SYMBOL(ccw_device_tm_intrg);
658 
659 /**
660  * ccw_device_get_schid() - obtain a subchannel id
661  * @cdev: device to obtain the id for
662  * @schid: where to fill in the values
663  */
664 void ccw_device_get_schid(struct ccw_device *cdev, struct subchannel_id *schid)
665 {
666 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
667 
668 	*schid = sch->schid;
669 }
670 EXPORT_SYMBOL_GPL(ccw_device_get_schid);
671 
672 EXPORT_SYMBOL(ccw_device_set_options_mask);
673 EXPORT_SYMBOL(ccw_device_set_options);
674 EXPORT_SYMBOL(ccw_device_clear_options);
675 EXPORT_SYMBOL(ccw_device_clear);
676 EXPORT_SYMBOL(ccw_device_halt);
677 EXPORT_SYMBOL(ccw_device_resume);
678 EXPORT_SYMBOL(ccw_device_start_timeout);
679 EXPORT_SYMBOL(ccw_device_start);
680 EXPORT_SYMBOL(ccw_device_start_timeout_key);
681 EXPORT_SYMBOL(ccw_device_start_key);
682 EXPORT_SYMBOL(ccw_device_get_ciw);
683 EXPORT_SYMBOL(ccw_device_get_path_mask);
684 EXPORT_SYMBOL_GPL(ccw_device_get_chp_desc);
685