xref: /openbmc/linux/drivers/s390/cio/device_ops.c (revision ddc141e5)
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_key() - start a s390 channel program with 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  *
174  * Start a S/390 channel program. When the interrupt arrives, the
175  * IRQ handler is called, either immediately, delayed (dev-end missing,
176  * or sense required) or never (no IRQ handler registered).
177  * Returns:
178  *  %0, if the operation was successful;
179  *  -%EBUSY, if the device is busy, or status pending;
180  *  -%EACCES, if no path specified in @lpm is operational;
181  *  -%ENODEV, if the device is not operational.
182  * Context:
183  *  Interrupts disabled, ccw device lock held
184  */
185 int ccw_device_start_key(struct ccw_device *cdev, struct ccw1 *cpa,
186 			 unsigned long intparm, __u8 lpm, __u8 key,
187 			 unsigned long flags)
188 {
189 	struct subchannel *sch;
190 	int ret;
191 
192 	if (!cdev || !cdev->dev.parent)
193 		return -ENODEV;
194 	sch = to_subchannel(cdev->dev.parent);
195 	if (!sch->schib.pmcw.ena)
196 		return -EINVAL;
197 	if (cdev->private->state == DEV_STATE_NOT_OPER)
198 		return -ENODEV;
199 	if (cdev->private->state == DEV_STATE_VERIFY) {
200 		/* Remember to fake irb when finished. */
201 		if (!cdev->private->flags.fake_irb) {
202 			cdev->private->flags.fake_irb = FAKE_CMD_IRB;
203 			cdev->private->intparm = intparm;
204 			return 0;
205 		} else
206 			/* There's already a fake I/O around. */
207 			return -EBUSY;
208 	}
209 	if (cdev->private->state != DEV_STATE_ONLINE ||
210 	    ((sch->schib.scsw.cmd.stctl & SCSW_STCTL_PRIM_STATUS) &&
211 	     !(sch->schib.scsw.cmd.stctl & SCSW_STCTL_SEC_STATUS)) ||
212 	    cdev->private->flags.doverify)
213 		return -EBUSY;
214 	ret = cio_set_options (sch, flags);
215 	if (ret)
216 		return ret;
217 	/* Adjust requested path mask to exclude unusable paths. */
218 	if (lpm) {
219 		lpm &= sch->lpm;
220 		if (lpm == 0)
221 			return -EACCES;
222 	}
223 	ret = cio_start_key (sch, cpa, lpm, key);
224 	switch (ret) {
225 	case 0:
226 		cdev->private->intparm = intparm;
227 		break;
228 	case -EACCES:
229 	case -ENODEV:
230 		dev_fsm_event(cdev, DEV_EVENT_VERIFY);
231 		break;
232 	}
233 	return ret;
234 }
235 
236 /**
237  * ccw_device_start_timeout_key() - start a s390 channel program with timeout and key
238  * @cdev: target ccw device
239  * @cpa: logical start address of channel program
240  * @intparm: user specific interruption parameter; will be presented back to
241  *	     @cdev's interrupt handler. Allows a device driver to associate
242  *	     the interrupt with a particular I/O request.
243  * @lpm: defines the channel path to be used for a specific I/O request. A
244  *	 value of 0 will make cio use the opm.
245  * @key: storage key to be used for the I/O
246  * @flags: additional flags; defines the action to be performed for I/O
247  *	   processing.
248  * @expires: timeout value in jiffies
249  *
250  * Start a S/390 channel program. When the interrupt arrives, the
251  * IRQ handler is called, either immediately, delayed (dev-end missing,
252  * or sense required) or never (no IRQ handler registered).
253  * This function notifies the device driver if the channel program has not
254  * completed during the time specified by @expires. If a timeout occurs, the
255  * channel program is terminated via xsch, hsch or csch, and the device's
256  * interrupt handler will be called with an irb containing ERR_PTR(-%ETIMEDOUT).
257  * Returns:
258  *  %0, if the operation was successful;
259  *  -%EBUSY, if the device is busy, or status pending;
260  *  -%EACCES, if no path specified in @lpm is operational;
261  *  -%ENODEV, if the device is not operational.
262  * Context:
263  *  Interrupts disabled, ccw device lock held
264  */
265 int ccw_device_start_timeout_key(struct ccw_device *cdev, struct ccw1 *cpa,
266 				 unsigned long intparm, __u8 lpm, __u8 key,
267 				 unsigned long flags, int expires)
268 {
269 	int ret;
270 
271 	if (!cdev)
272 		return -ENODEV;
273 	ccw_device_set_timeout(cdev, expires);
274 	ret = ccw_device_start_key(cdev, cpa, intparm, lpm, key, flags);
275 	if (ret != 0)
276 		ccw_device_set_timeout(cdev, 0);
277 	return ret;
278 }
279 
280 /**
281  * ccw_device_start() - start a s390 channel program
282  * @cdev: target ccw device
283  * @cpa: logical start address of channel program
284  * @intparm: user specific interruption parameter; will be presented back to
285  *	     @cdev's interrupt handler. Allows a device driver to associate
286  *	     the interrupt with a particular I/O request.
287  * @lpm: defines the channel path to be used for a specific I/O request. A
288  *	 value of 0 will make cio use the opm.
289  * @flags: additional flags; defines the action to be performed for I/O
290  *	   processing.
291  *
292  * Start a S/390 channel program. When the interrupt arrives, the
293  * IRQ handler is called, either immediately, delayed (dev-end missing,
294  * or sense required) or never (no IRQ handler registered).
295  * Returns:
296  *  %0, if the operation was successful;
297  *  -%EBUSY, if the device is busy, or status pending;
298  *  -%EACCES, if no path specified in @lpm is operational;
299  *  -%ENODEV, if the device is not operational.
300  * Context:
301  *  Interrupts disabled, ccw device lock held
302  */
303 int ccw_device_start(struct ccw_device *cdev, struct ccw1 *cpa,
304 		     unsigned long intparm, __u8 lpm, unsigned long flags)
305 {
306 	return ccw_device_start_key(cdev, cpa, intparm, lpm,
307 				    PAGE_DEFAULT_KEY, flags);
308 }
309 
310 /**
311  * ccw_device_start_timeout() - start a s390 channel program with timeout
312  * @cdev: target ccw device
313  * @cpa: logical start address of channel program
314  * @intparm: user specific interruption parameter; will be presented back to
315  *	     @cdev's interrupt handler. Allows a device driver to associate
316  *	     the interrupt with a particular I/O request.
317  * @lpm: defines the channel path to be used for a specific I/O request. A
318  *	 value of 0 will make cio use the opm.
319  * @flags: additional flags; defines the action to be performed for I/O
320  *	   processing.
321  * @expires: timeout value in jiffies
322  *
323  * Start a S/390 channel program. When the interrupt arrives, the
324  * IRQ handler is called, either immediately, delayed (dev-end missing,
325  * or sense required) or never (no IRQ handler registered).
326  * This function notifies the device driver if the channel program has not
327  * completed during the time specified by @expires. If a timeout occurs, the
328  * channel program is terminated via xsch, hsch or csch, and the device's
329  * interrupt handler will be called with an irb containing ERR_PTR(-%ETIMEDOUT).
330  * Returns:
331  *  %0, if the operation was successful;
332  *  -%EBUSY, if the device is busy, or status pending;
333  *  -%EACCES, if no path specified in @lpm is operational;
334  *  -%ENODEV, if the device is not operational.
335  * Context:
336  *  Interrupts disabled, ccw device lock held
337  */
338 int ccw_device_start_timeout(struct ccw_device *cdev, struct ccw1 *cpa,
339 			     unsigned long intparm, __u8 lpm,
340 			     unsigned long flags, int expires)
341 {
342 	return ccw_device_start_timeout_key(cdev, cpa, intparm, lpm,
343 					    PAGE_DEFAULT_KEY, flags,
344 					    expires);
345 }
346 
347 
348 /**
349  * ccw_device_halt() - halt I/O request processing
350  * @cdev: target ccw device
351  * @intparm: interruption parameter; value is only used if no I/O is
352  *	     outstanding, otherwise the intparm associated with the I/O request
353  *	     is returned
354  *
355  * ccw_device_halt() calls hsch on @cdev's subchannel.
356  * Returns:
357  *  %0 on success,
358  *  -%ENODEV on device not operational,
359  *  -%EINVAL on invalid device state,
360  *  -%EBUSY on device busy or interrupt pending.
361  * Context:
362  *  Interrupts disabled, ccw device lock held
363  */
364 int ccw_device_halt(struct ccw_device *cdev, unsigned long intparm)
365 {
366 	struct subchannel *sch;
367 	int ret;
368 
369 	if (!cdev || !cdev->dev.parent)
370 		return -ENODEV;
371 	sch = to_subchannel(cdev->dev.parent);
372 	if (!sch->schib.pmcw.ena)
373 		return -EINVAL;
374 	if (cdev->private->state == DEV_STATE_NOT_OPER)
375 		return -ENODEV;
376 	if (cdev->private->state != DEV_STATE_ONLINE &&
377 	    cdev->private->state != DEV_STATE_W4SENSE)
378 		return -EINVAL;
379 
380 	ret = cio_halt(sch);
381 	if (ret == 0)
382 		cdev->private->intparm = intparm;
383 	return ret;
384 }
385 
386 /**
387  * ccw_device_resume() - resume channel program execution
388  * @cdev: target ccw device
389  *
390  * ccw_device_resume() calls rsch on @cdev's subchannel.
391  * Returns:
392  *  %0 on success,
393  *  -%ENODEV on device not operational,
394  *  -%EINVAL on invalid device state,
395  *  -%EBUSY on device busy or interrupt pending.
396  * Context:
397  *  Interrupts disabled, ccw device lock held
398  */
399 int ccw_device_resume(struct ccw_device *cdev)
400 {
401 	struct subchannel *sch;
402 
403 	if (!cdev || !cdev->dev.parent)
404 		return -ENODEV;
405 	sch = to_subchannel(cdev->dev.parent);
406 	if (!sch->schib.pmcw.ena)
407 		return -EINVAL;
408 	if (cdev->private->state == DEV_STATE_NOT_OPER)
409 		return -ENODEV;
410 	if (cdev->private->state != DEV_STATE_ONLINE ||
411 	    !(sch->schib.scsw.cmd.actl & SCSW_ACTL_SUSPENDED))
412 		return -EINVAL;
413 	return cio_resume(sch);
414 }
415 
416 /**
417  * ccw_device_get_ciw() - Search for CIW command in extended sense data.
418  * @cdev: ccw device to inspect
419  * @ct: command type to look for
420  *
421  * During SenseID, command information words (CIWs) describing special
422  * commands available to the device may have been stored in the extended
423  * sense data. This function searches for CIWs of a specified command
424  * type in the extended sense data.
425  * Returns:
426  *  %NULL if no extended sense data has been stored or if no CIW of the
427  *  specified command type could be found,
428  *  else a pointer to the CIW of the specified command type.
429  */
430 struct ciw *ccw_device_get_ciw(struct ccw_device *cdev, __u32 ct)
431 {
432 	int ciw_cnt;
433 
434 	if (cdev->private->flags.esid == 0)
435 		return NULL;
436 	for (ciw_cnt = 0; ciw_cnt < MAX_CIWS; ciw_cnt++)
437 		if (cdev->private->senseid.ciw[ciw_cnt].ct == ct)
438 			return cdev->private->senseid.ciw + ciw_cnt;
439 	return NULL;
440 }
441 
442 /**
443  * ccw_device_get_path_mask() - get currently available paths
444  * @cdev: ccw device to be queried
445  * Returns:
446  *  %0 if no subchannel for the device is available,
447  *  else the mask of currently available paths for the ccw device's subchannel.
448  */
449 __u8 ccw_device_get_path_mask(struct ccw_device *cdev)
450 {
451 	struct subchannel *sch;
452 
453 	if (!cdev->dev.parent)
454 		return 0;
455 
456 	sch = to_subchannel(cdev->dev.parent);
457 	return sch->lpm;
458 }
459 
460 /**
461  * ccw_device_get_chp_desc() - return newly allocated channel-path descriptor
462  * @cdev: device to obtain the descriptor for
463  * @chp_idx: index of the channel path
464  *
465  * On success return a newly allocated copy of the channel-path description
466  * data associated with the given channel path. Return %NULL on error.
467  */
468 struct channel_path_desc *ccw_device_get_chp_desc(struct ccw_device *cdev,
469 						  int chp_idx)
470 {
471 	struct subchannel *sch;
472 	struct chp_id chpid;
473 
474 	sch = to_subchannel(cdev->dev.parent);
475 	chp_id_init(&chpid);
476 	chpid.id = sch->schib.pmcw.chpid[chp_idx];
477 	return chp_get_chp_desc(chpid);
478 }
479 
480 /**
481  * ccw_device_get_id() - obtain a ccw device id
482  * @cdev: device to obtain the id for
483  * @dev_id: where to fill in the values
484  */
485 void ccw_device_get_id(struct ccw_device *cdev, struct ccw_dev_id *dev_id)
486 {
487 	*dev_id = cdev->private->dev_id;
488 }
489 EXPORT_SYMBOL(ccw_device_get_id);
490 
491 /**
492  * ccw_device_tm_start_key() - perform start function
493  * @cdev: ccw device on which to perform the start function
494  * @tcw: transport-command word to be started
495  * @intparm: user defined parameter to be passed to the interrupt handler
496  * @lpm: mask of paths to use
497  * @key: storage key to use for storage access
498  *
499  * Start the tcw on the given ccw device. Return zero on success, non-zero
500  * otherwise.
501  */
502 int ccw_device_tm_start_key(struct ccw_device *cdev, struct tcw *tcw,
503 			    unsigned long intparm, u8 lpm, u8 key)
504 {
505 	struct subchannel *sch;
506 	int rc;
507 
508 	sch = to_subchannel(cdev->dev.parent);
509 	if (!sch->schib.pmcw.ena)
510 		return -EINVAL;
511 	if (cdev->private->state == DEV_STATE_VERIFY) {
512 		/* Remember to fake irb when finished. */
513 		if (!cdev->private->flags.fake_irb) {
514 			cdev->private->flags.fake_irb = FAKE_TM_IRB;
515 			cdev->private->intparm = intparm;
516 			return 0;
517 		} else
518 			/* There's already a fake I/O around. */
519 			return -EBUSY;
520 	}
521 	if (cdev->private->state != DEV_STATE_ONLINE)
522 		return -EIO;
523 	/* Adjust requested path mask to exclude unusable paths. */
524 	if (lpm) {
525 		lpm &= sch->lpm;
526 		if (lpm == 0)
527 			return -EACCES;
528 	}
529 	rc = cio_tm_start_key(sch, tcw, lpm, key);
530 	if (rc == 0)
531 		cdev->private->intparm = intparm;
532 	return rc;
533 }
534 EXPORT_SYMBOL(ccw_device_tm_start_key);
535 
536 /**
537  * ccw_device_tm_start_timeout_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  * @expires: time span in jiffies after which to abort request
544  *
545  * Start the tcw on the given ccw device. Return zero on success, non-zero
546  * otherwise.
547  */
548 int ccw_device_tm_start_timeout_key(struct ccw_device *cdev, struct tcw *tcw,
549 				    unsigned long intparm, u8 lpm, u8 key,
550 				    int expires)
551 {
552 	int ret;
553 
554 	ccw_device_set_timeout(cdev, expires);
555 	ret = ccw_device_tm_start_key(cdev, tcw, intparm, lpm, key);
556 	if (ret != 0)
557 		ccw_device_set_timeout(cdev, 0);
558 	return ret;
559 }
560 EXPORT_SYMBOL(ccw_device_tm_start_timeout_key);
561 
562 /**
563  * ccw_device_tm_start() - perform start function
564  * @cdev: ccw device on which to perform the start function
565  * @tcw: transport-command word to be started
566  * @intparm: user defined parameter to be passed to the interrupt handler
567  * @lpm: mask of paths to use
568  *
569  * Start the tcw on the given ccw device. Return zero on success, non-zero
570  * otherwise.
571  */
572 int ccw_device_tm_start(struct ccw_device *cdev, struct tcw *tcw,
573 			unsigned long intparm, u8 lpm)
574 {
575 	return ccw_device_tm_start_key(cdev, tcw, intparm, lpm,
576 				       PAGE_DEFAULT_KEY);
577 }
578 EXPORT_SYMBOL(ccw_device_tm_start);
579 
580 /**
581  * ccw_device_tm_start_timeout() - perform start function
582  * @cdev: ccw device on which to perform the start function
583  * @tcw: transport-command word to be started
584  * @intparm: user defined parameter to be passed to the interrupt handler
585  * @lpm: mask of paths to use
586  * @expires: time span in jiffies after which to abort request
587  *
588  * Start the tcw on the given ccw device. Return zero on success, non-zero
589  * otherwise.
590  */
591 int ccw_device_tm_start_timeout(struct ccw_device *cdev, struct tcw *tcw,
592 			       unsigned long intparm, u8 lpm, int expires)
593 {
594 	return ccw_device_tm_start_timeout_key(cdev, tcw, intparm, lpm,
595 					       PAGE_DEFAULT_KEY, expires);
596 }
597 EXPORT_SYMBOL(ccw_device_tm_start_timeout);
598 
599 /**
600  * ccw_device_get_mdc() - accumulate max data count
601  * @cdev: ccw device for which the max data count is accumulated
602  * @mask: mask of paths to use
603  *
604  * Return the number of 64K-bytes blocks all paths at least support
605  * for a transport command. Return values <= 0 indicate failures.
606  */
607 int ccw_device_get_mdc(struct ccw_device *cdev, u8 mask)
608 {
609 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
610 	struct channel_path *chp;
611 	struct chp_id chpid;
612 	int mdc = 0, i;
613 
614 	/* Adjust requested path mask to excluded varied off paths. */
615 	if (mask)
616 		mask &= sch->lpm;
617 	else
618 		mask = sch->lpm;
619 
620 	chp_id_init(&chpid);
621 	for (i = 0; i < 8; i++) {
622 		if (!(mask & (0x80 >> i)))
623 			continue;
624 		chpid.id = sch->schib.pmcw.chpid[i];
625 		chp = chpid_to_chp(chpid);
626 		if (!chp)
627 			continue;
628 
629 		mutex_lock(&chp->lock);
630 		if (!chp->desc_fmt1.f) {
631 			mutex_unlock(&chp->lock);
632 			return 0;
633 		}
634 		if (!chp->desc_fmt1.r)
635 			mdc = 1;
636 		mdc = mdc ? min_t(int, mdc, chp->desc_fmt1.mdc) :
637 			    chp->desc_fmt1.mdc;
638 		mutex_unlock(&chp->lock);
639 	}
640 
641 	return mdc;
642 }
643 EXPORT_SYMBOL(ccw_device_get_mdc);
644 
645 /**
646  * ccw_device_tm_intrg() - perform interrogate function
647  * @cdev: ccw device on which to perform the interrogate function
648  *
649  * Perform an interrogate function on the given ccw device. Return zero on
650  * success, non-zero otherwise.
651  */
652 int ccw_device_tm_intrg(struct ccw_device *cdev)
653 {
654 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
655 
656 	if (!sch->schib.pmcw.ena)
657 		return -EINVAL;
658 	if (cdev->private->state != DEV_STATE_ONLINE)
659 		return -EIO;
660 	if (!scsw_is_tm(&sch->schib.scsw) ||
661 	    !(scsw_actl(&sch->schib.scsw) & SCSW_ACTL_START_PEND))
662 		return -EINVAL;
663 	return cio_tm_intrg(sch);
664 }
665 EXPORT_SYMBOL(ccw_device_tm_intrg);
666 
667 /**
668  * ccw_device_get_schid() - obtain a subchannel id
669  * @cdev: device to obtain the id for
670  * @schid: where to fill in the values
671  */
672 void ccw_device_get_schid(struct ccw_device *cdev, struct subchannel_id *schid)
673 {
674 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
675 
676 	*schid = sch->schid;
677 }
678 EXPORT_SYMBOL_GPL(ccw_device_get_schid);
679 
680 EXPORT_SYMBOL(ccw_device_set_options_mask);
681 EXPORT_SYMBOL(ccw_device_set_options);
682 EXPORT_SYMBOL(ccw_device_clear_options);
683 EXPORT_SYMBOL(ccw_device_clear);
684 EXPORT_SYMBOL(ccw_device_halt);
685 EXPORT_SYMBOL(ccw_device_resume);
686 EXPORT_SYMBOL(ccw_device_start_timeout);
687 EXPORT_SYMBOL(ccw_device_start);
688 EXPORT_SYMBOL(ccw_device_start_timeout_key);
689 EXPORT_SYMBOL(ccw_device_start_key);
690 EXPORT_SYMBOL(ccw_device_get_ciw);
691 EXPORT_SYMBOL(ccw_device_get_path_mask);
692 EXPORT_SYMBOL_GPL(ccw_device_get_chp_desc);
693