xref: /openbmc/linux/drivers/s390/cio/device_ops.c (revision 8730046c)
1 /*
2  * Copyright IBM Corp. 2002, 2009
3  *
4  * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
5  *	      Cornelia Huck (cornelia.huck@de.ibm.com)
6  *
7  * License: GPL
8  */
9 #include <linux/export.h>
10 #include <linux/init.h>
11 #include <linux/errno.h>
12 #include <linux/slab.h>
13 #include <linux/list.h>
14 #include <linux/device.h>
15 #include <linux/delay.h>
16 #include <linux/completion.h>
17 
18 #include <asm/ccwdev.h>
19 #include <asm/idals.h>
20 #include <asm/chpid.h>
21 #include <asm/fcx.h>
22 
23 #include "cio.h"
24 #include "cio_debug.h"
25 #include "css.h"
26 #include "chsc.h"
27 #include "device.h"
28 #include "chp.h"
29 
30 /**
31  * ccw_device_set_options_mask() - set some options and unset the rest
32  * @cdev: device for which the options are to be set
33  * @flags: options to be set
34  *
35  * All flags specified in @flags are set, all flags not specified in @flags
36  * are cleared.
37  * Returns:
38  *   %0 on success, -%EINVAL on an invalid flag combination.
39  */
40 int ccw_device_set_options_mask(struct ccw_device *cdev, unsigned long flags)
41 {
42        /*
43 	* The flag usage is mutal exclusive ...
44 	*/
45 	if ((flags & CCWDEV_EARLY_NOTIFICATION) &&
46 	    (flags & CCWDEV_REPORT_ALL))
47 		return -EINVAL;
48 	cdev->private->options.fast = (flags & CCWDEV_EARLY_NOTIFICATION) != 0;
49 	cdev->private->options.repall = (flags & CCWDEV_REPORT_ALL) != 0;
50 	cdev->private->options.pgroup = (flags & CCWDEV_DO_PATHGROUP) != 0;
51 	cdev->private->options.force = (flags & CCWDEV_ALLOW_FORCE) != 0;
52 	cdev->private->options.mpath = (flags & CCWDEV_DO_MULTIPATH) != 0;
53 	return 0;
54 }
55 
56 /**
57  * ccw_device_set_options() - set some options
58  * @cdev: device for which the options are to be set
59  * @flags: options to be set
60  *
61  * All flags specified in @flags are set, the remainder is left untouched.
62  * Returns:
63  *   %0 on success, -%EINVAL if an invalid flag combination would ensue.
64  */
65 int ccw_device_set_options(struct ccw_device *cdev, unsigned long flags)
66 {
67        /*
68 	* The flag usage is mutal exclusive ...
69 	*/
70 	if (((flags & CCWDEV_EARLY_NOTIFICATION) &&
71 	    (flags & CCWDEV_REPORT_ALL)) ||
72 	    ((flags & CCWDEV_EARLY_NOTIFICATION) &&
73 	     cdev->private->options.repall) ||
74 	    ((flags & CCWDEV_REPORT_ALL) &&
75 	     cdev->private->options.fast))
76 		return -EINVAL;
77 	cdev->private->options.fast |= (flags & CCWDEV_EARLY_NOTIFICATION) != 0;
78 	cdev->private->options.repall |= (flags & CCWDEV_REPORT_ALL) != 0;
79 	cdev->private->options.pgroup |= (flags & CCWDEV_DO_PATHGROUP) != 0;
80 	cdev->private->options.force |= (flags & CCWDEV_ALLOW_FORCE) != 0;
81 	cdev->private->options.mpath |= (flags & CCWDEV_DO_MULTIPATH) != 0;
82 	return 0;
83 }
84 
85 /**
86  * ccw_device_clear_options() - clear some options
87  * @cdev: device for which the options are to be cleared
88  * @flags: options to be cleared
89  *
90  * All flags specified in @flags are cleared, the remainder is left untouched.
91  */
92 void ccw_device_clear_options(struct ccw_device *cdev, unsigned long flags)
93 {
94 	cdev->private->options.fast &= (flags & CCWDEV_EARLY_NOTIFICATION) == 0;
95 	cdev->private->options.repall &= (flags & CCWDEV_REPORT_ALL) == 0;
96 	cdev->private->options.pgroup &= (flags & CCWDEV_DO_PATHGROUP) == 0;
97 	cdev->private->options.force &= (flags & CCWDEV_ALLOW_FORCE) == 0;
98 	cdev->private->options.mpath &= (flags & CCWDEV_DO_MULTIPATH) == 0;
99 }
100 
101 /**
102  * ccw_device_is_pathgroup() - determine if paths to this device are grouped
103  * @cdev: ccw device
104  *
105  * Return non-zero if there is a path group, zero otherwise.
106  */
107 int ccw_device_is_pathgroup(struct ccw_device *cdev)
108 {
109 	return cdev->private->flags.pgroup;
110 }
111 EXPORT_SYMBOL(ccw_device_is_pathgroup);
112 
113 /**
114  * ccw_device_is_multipath() - determine if device is operating in multipath mode
115  * @cdev: ccw device
116  *
117  * Return non-zero if device is operating in multipath mode, zero otherwise.
118  */
119 int ccw_device_is_multipath(struct ccw_device *cdev)
120 {
121 	return cdev->private->flags.mpath;
122 }
123 EXPORT_SYMBOL(ccw_device_is_multipath);
124 
125 /**
126  * ccw_device_clear() - terminate I/O request processing
127  * @cdev: target ccw device
128  * @intparm: interruption parameter; value is only used if no I/O is
129  *	     outstanding, otherwise the intparm associated with the I/O request
130  *	     is returned
131  *
132  * ccw_device_clear() calls csch on @cdev's subchannel.
133  * Returns:
134  *  %0 on success,
135  *  -%ENODEV on device not operational,
136  *  -%EINVAL on invalid device state.
137  * Context:
138  *  Interrupts disabled, ccw device lock held
139  */
140 int ccw_device_clear(struct ccw_device *cdev, unsigned long intparm)
141 {
142 	struct subchannel *sch;
143 	int ret;
144 
145 	if (!cdev || !cdev->dev.parent)
146 		return -ENODEV;
147 	sch = to_subchannel(cdev->dev.parent);
148 	if (!sch->schib.pmcw.ena)
149 		return -EINVAL;
150 	if (cdev->private->state == DEV_STATE_NOT_OPER)
151 		return -ENODEV;
152 	if (cdev->private->state != DEV_STATE_ONLINE &&
153 	    cdev->private->state != DEV_STATE_W4SENSE)
154 		return -EINVAL;
155 
156 	ret = cio_clear(sch);
157 	if (ret == 0)
158 		cdev->private->intparm = intparm;
159 	return ret;
160 }
161 
162 /**
163  * ccw_device_start_key() - start a s390 channel program with key
164  * @cdev: target ccw device
165  * @cpa: logical start address of channel program
166  * @intparm: user specific interruption parameter; will be presented back to
167  *	     @cdev's interrupt handler. Allows a device driver to associate
168  *	     the interrupt with a particular I/O request.
169  * @lpm: defines the channel path to be used for a specific I/O request. A
170  *	 value of 0 will make cio use the opm.
171  * @key: storage key to be used for the I/O
172  * @flags: additional flags; defines the action to be performed for I/O
173  *	   processing.
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  * Returns:
179  *  %0, if the operation was successful;
180  *  -%EBUSY, if the device is busy, or status pending;
181  *  -%EACCES, if no path specified in @lpm is operational;
182  *  -%ENODEV, if the device is not operational.
183  * Context:
184  *  Interrupts disabled, ccw device lock held
185  */
186 int ccw_device_start_key(struct ccw_device *cdev, struct ccw1 *cpa,
187 			 unsigned long intparm, __u8 lpm, __u8 key,
188 			 unsigned long flags)
189 {
190 	struct subchannel *sch;
191 	int ret;
192 
193 	if (!cdev || !cdev->dev.parent)
194 		return -ENODEV;
195 	sch = to_subchannel(cdev->dev.parent);
196 	if (!sch->schib.pmcw.ena)
197 		return -EINVAL;
198 	if (cdev->private->state == DEV_STATE_NOT_OPER)
199 		return -ENODEV;
200 	if (cdev->private->state == DEV_STATE_VERIFY) {
201 		/* Remember to fake irb when finished. */
202 		if (!cdev->private->flags.fake_irb) {
203 			cdev->private->flags.fake_irb = FAKE_CMD_IRB;
204 			cdev->private->intparm = intparm;
205 			return 0;
206 		} else
207 			/* There's already a fake I/O around. */
208 			return -EBUSY;
209 	}
210 	if (cdev->private->state != DEV_STATE_ONLINE ||
211 	    ((sch->schib.scsw.cmd.stctl & SCSW_STCTL_PRIM_STATUS) &&
212 	     !(sch->schib.scsw.cmd.stctl & SCSW_STCTL_SEC_STATUS)) ||
213 	    cdev->private->flags.doverify)
214 		return -EBUSY;
215 	ret = cio_set_options (sch, flags);
216 	if (ret)
217 		return ret;
218 	/* Adjust requested path mask to exclude unusable paths. */
219 	if (lpm) {
220 		lpm &= sch->lpm;
221 		if (lpm == 0)
222 			return -EACCES;
223 	}
224 	ret = cio_start_key (sch, cpa, lpm, key);
225 	switch (ret) {
226 	case 0:
227 		cdev->private->intparm = intparm;
228 		break;
229 	case -EACCES:
230 	case -ENODEV:
231 		dev_fsm_event(cdev, DEV_EVENT_VERIFY);
232 		break;
233 	}
234 	return ret;
235 }
236 
237 /**
238  * ccw_device_start_timeout_key() - start a s390 channel program with timeout and key
239  * @cdev: target ccw device
240  * @cpa: logical start address of channel program
241  * @intparm: user specific interruption parameter; will be presented back to
242  *	     @cdev's interrupt handler. Allows a device driver to associate
243  *	     the interrupt with a particular I/O request.
244  * @lpm: defines the channel path to be used for a specific I/O request. A
245  *	 value of 0 will make cio use the opm.
246  * @key: storage key to be used for the I/O
247  * @flags: additional flags; defines the action to be performed for I/O
248  *	   processing.
249  * @expires: timeout value in jiffies
250  *
251  * Start a S/390 channel program. When the interrupt arrives, the
252  * IRQ handler is called, either immediately, delayed (dev-end missing,
253  * or sense required) or never (no IRQ handler registered).
254  * This function notifies the device driver if the channel program has not
255  * completed during the time specified by @expires. If a timeout occurs, the
256  * channel program is terminated via xsch, hsch or csch, and the device's
257  * interrupt handler will be called with an irb containing ERR_PTR(-%ETIMEDOUT).
258  * Returns:
259  *  %0, if the operation was successful;
260  *  -%EBUSY, if the device is busy, or status pending;
261  *  -%EACCES, if no path specified in @lpm is operational;
262  *  -%ENODEV, if the device is not operational.
263  * Context:
264  *  Interrupts disabled, ccw device lock held
265  */
266 int ccw_device_start_timeout_key(struct ccw_device *cdev, struct ccw1 *cpa,
267 				 unsigned long intparm, __u8 lpm, __u8 key,
268 				 unsigned long flags, int expires)
269 {
270 	int ret;
271 
272 	if (!cdev)
273 		return -ENODEV;
274 	ccw_device_set_timeout(cdev, expires);
275 	ret = ccw_device_start_key(cdev, cpa, intparm, lpm, key, flags);
276 	if (ret != 0)
277 		ccw_device_set_timeout(cdev, 0);
278 	return ret;
279 }
280 
281 /**
282  * ccw_device_start() - start a s390 channel program
283  * @cdev: target ccw device
284  * @cpa: logical start address of channel program
285  * @intparm: user specific interruption parameter; will be presented back to
286  *	     @cdev's interrupt handler. Allows a device driver to associate
287  *	     the interrupt with a particular I/O request.
288  * @lpm: defines the channel path to be used for a specific I/O request. A
289  *	 value of 0 will make cio use the opm.
290  * @flags: additional flags; defines the action to be performed for I/O
291  *	   processing.
292  *
293  * Start a S/390 channel program. When the interrupt arrives, the
294  * IRQ handler is called, either immediately, delayed (dev-end missing,
295  * or sense required) or never (no IRQ handler registered).
296  * Returns:
297  *  %0, if the operation was successful;
298  *  -%EBUSY, if the device is busy, or status pending;
299  *  -%EACCES, if no path specified in @lpm is operational;
300  *  -%ENODEV, if the device is not operational.
301  * Context:
302  *  Interrupts disabled, ccw device lock held
303  */
304 int ccw_device_start(struct ccw_device *cdev, struct ccw1 *cpa,
305 		     unsigned long intparm, __u8 lpm, unsigned long flags)
306 {
307 	return ccw_device_start_key(cdev, cpa, intparm, lpm,
308 				    PAGE_DEFAULT_KEY, flags);
309 }
310 
311 /**
312  * ccw_device_start_timeout() - start a s390 channel program with timeout
313  * @cdev: target ccw device
314  * @cpa: logical start address of channel program
315  * @intparm: user specific interruption parameter; will be presented back to
316  *	     @cdev's interrupt handler. Allows a device driver to associate
317  *	     the interrupt with a particular I/O request.
318  * @lpm: defines the channel path to be used for a specific I/O request. A
319  *	 value of 0 will make cio use the opm.
320  * @flags: additional flags; defines the action to be performed for I/O
321  *	   processing.
322  * @expires: timeout value in jiffies
323  *
324  * Start a S/390 channel program. When the interrupt arrives, the
325  * IRQ handler is called, either immediately, delayed (dev-end missing,
326  * or sense required) or never (no IRQ handler registered).
327  * This function notifies the device driver if the channel program has not
328  * completed during the time specified by @expires. If a timeout occurs, the
329  * channel program is terminated via xsch, hsch or csch, and the device's
330  * interrupt handler will be called with an irb containing ERR_PTR(-%ETIMEDOUT).
331  * Returns:
332  *  %0, if the operation was successful;
333  *  -%EBUSY, if the device is busy, or status pending;
334  *  -%EACCES, if no path specified in @lpm is operational;
335  *  -%ENODEV, if the device is not operational.
336  * Context:
337  *  Interrupts disabled, ccw device lock held
338  */
339 int ccw_device_start_timeout(struct ccw_device *cdev, struct ccw1 *cpa,
340 			     unsigned long intparm, __u8 lpm,
341 			     unsigned long flags, int expires)
342 {
343 	return ccw_device_start_timeout_key(cdev, cpa, intparm, lpm,
344 					    PAGE_DEFAULT_KEY, flags,
345 					    expires);
346 }
347 
348 
349 /**
350  * ccw_device_halt() - halt I/O request processing
351  * @cdev: target ccw device
352  * @intparm: interruption parameter; value is only used if no I/O is
353  *	     outstanding, otherwise the intparm associated with the I/O request
354  *	     is returned
355  *
356  * ccw_device_halt() calls hsch on @cdev's subchannel.
357  * Returns:
358  *  %0 on success,
359  *  -%ENODEV on device not operational,
360  *  -%EINVAL on invalid device state,
361  *  -%EBUSY on device busy or interrupt pending.
362  * Context:
363  *  Interrupts disabled, ccw device lock held
364  */
365 int ccw_device_halt(struct ccw_device *cdev, unsigned long intparm)
366 {
367 	struct subchannel *sch;
368 	int ret;
369 
370 	if (!cdev || !cdev->dev.parent)
371 		return -ENODEV;
372 	sch = to_subchannel(cdev->dev.parent);
373 	if (!sch->schib.pmcw.ena)
374 		return -EINVAL;
375 	if (cdev->private->state == DEV_STATE_NOT_OPER)
376 		return -ENODEV;
377 	if (cdev->private->state != DEV_STATE_ONLINE &&
378 	    cdev->private->state != DEV_STATE_W4SENSE)
379 		return -EINVAL;
380 
381 	ret = cio_halt(sch);
382 	if (ret == 0)
383 		cdev->private->intparm = intparm;
384 	return ret;
385 }
386 
387 /**
388  * ccw_device_resume() - resume channel program execution
389  * @cdev: target ccw device
390  *
391  * ccw_device_resume() calls rsch on @cdev's subchannel.
392  * Returns:
393  *  %0 on success,
394  *  -%ENODEV on device not operational,
395  *  -%EINVAL on invalid device state,
396  *  -%EBUSY on device busy or interrupt pending.
397  * Context:
398  *  Interrupts disabled, ccw device lock held
399  */
400 int ccw_device_resume(struct ccw_device *cdev)
401 {
402 	struct subchannel *sch;
403 
404 	if (!cdev || !cdev->dev.parent)
405 		return -ENODEV;
406 	sch = to_subchannel(cdev->dev.parent);
407 	if (!sch->schib.pmcw.ena)
408 		return -EINVAL;
409 	if (cdev->private->state == DEV_STATE_NOT_OPER)
410 		return -ENODEV;
411 	if (cdev->private->state != DEV_STATE_ONLINE ||
412 	    !(sch->schib.scsw.cmd.actl & SCSW_ACTL_SUSPENDED))
413 		return -EINVAL;
414 	return cio_resume(sch);
415 }
416 
417 /**
418  * ccw_device_get_ciw() - Search for CIW command in extended sense data.
419  * @cdev: ccw device to inspect
420  * @ct: command type to look for
421  *
422  * During SenseID, command information words (CIWs) describing special
423  * commands available to the device may have been stored in the extended
424  * sense data. This function searches for CIWs of a specified command
425  * type in the extended sense data.
426  * Returns:
427  *  %NULL if no extended sense data has been stored or if no CIW of the
428  *  specified command type could be found,
429  *  else a pointer to the CIW of the specified command type.
430  */
431 struct ciw *ccw_device_get_ciw(struct ccw_device *cdev, __u32 ct)
432 {
433 	int ciw_cnt;
434 
435 	if (cdev->private->flags.esid == 0)
436 		return NULL;
437 	for (ciw_cnt = 0; ciw_cnt < MAX_CIWS; ciw_cnt++)
438 		if (cdev->private->senseid.ciw[ciw_cnt].ct == ct)
439 			return cdev->private->senseid.ciw + ciw_cnt;
440 	return NULL;
441 }
442 
443 /**
444  * ccw_device_get_path_mask() - get currently available paths
445  * @cdev: ccw device to be queried
446  * Returns:
447  *  %0 if no subchannel for the device is available,
448  *  else the mask of currently available paths for the ccw device's subchannel.
449  */
450 __u8 ccw_device_get_path_mask(struct ccw_device *cdev)
451 {
452 	struct subchannel *sch;
453 
454 	if (!cdev->dev.parent)
455 		return 0;
456 
457 	sch = to_subchannel(cdev->dev.parent);
458 	return sch->lpm;
459 }
460 
461 /**
462  * ccw_device_get_chp_desc() - return newly allocated channel-path descriptor
463  * @cdev: device to obtain the descriptor for
464  * @chp_idx: index of the channel path
465  *
466  * On success return a newly allocated copy of the channel-path description
467  * data associated with the given channel path. Return %NULL on error.
468  */
469 struct channel_path_desc *ccw_device_get_chp_desc(struct ccw_device *cdev,
470 						  int chp_idx)
471 {
472 	struct subchannel *sch;
473 	struct chp_id chpid;
474 
475 	sch = to_subchannel(cdev->dev.parent);
476 	chp_id_init(&chpid);
477 	chpid.id = sch->schib.pmcw.chpid[chp_idx];
478 	return chp_get_chp_desc(chpid);
479 }
480 
481 /**
482  * ccw_device_get_id() - obtain a ccw device id
483  * @cdev: device to obtain the id for
484  * @dev_id: where to fill in the values
485  */
486 void ccw_device_get_id(struct ccw_device *cdev, struct ccw_dev_id *dev_id)
487 {
488 	*dev_id = cdev->private->dev_id;
489 }
490 EXPORT_SYMBOL(ccw_device_get_id);
491 
492 /**
493  * ccw_device_tm_start_key() - perform start function
494  * @cdev: ccw device on which to perform the start function
495  * @tcw: transport-command word to be started
496  * @intparm: user defined parameter to be passed to the interrupt handler
497  * @lpm: mask of paths to use
498  * @key: storage key to use for storage access
499  *
500  * Start the tcw on the given ccw device. Return zero on success, non-zero
501  * otherwise.
502  */
503 int ccw_device_tm_start_key(struct ccw_device *cdev, struct tcw *tcw,
504 			    unsigned long intparm, u8 lpm, u8 key)
505 {
506 	struct subchannel *sch;
507 	int rc;
508 
509 	sch = to_subchannel(cdev->dev.parent);
510 	if (!sch->schib.pmcw.ena)
511 		return -EINVAL;
512 	if (cdev->private->state == DEV_STATE_VERIFY) {
513 		/* Remember to fake irb when finished. */
514 		if (!cdev->private->flags.fake_irb) {
515 			cdev->private->flags.fake_irb = FAKE_TM_IRB;
516 			cdev->private->intparm = intparm;
517 			return 0;
518 		} else
519 			/* There's already a fake I/O around. */
520 			return -EBUSY;
521 	}
522 	if (cdev->private->state != DEV_STATE_ONLINE)
523 		return -EIO;
524 	/* Adjust requested path mask to exclude unusable paths. */
525 	if (lpm) {
526 		lpm &= sch->lpm;
527 		if (lpm == 0)
528 			return -EACCES;
529 	}
530 	rc = cio_tm_start_key(sch, tcw, lpm, key);
531 	if (rc == 0)
532 		cdev->private->intparm = intparm;
533 	return rc;
534 }
535 EXPORT_SYMBOL(ccw_device_tm_start_key);
536 
537 /**
538  * ccw_device_tm_start_timeout_key() - perform start function
539  * @cdev: ccw device on which to perform the start function
540  * @tcw: transport-command word to be started
541  * @intparm: user defined parameter to be passed to the interrupt handler
542  * @lpm: mask of paths to use
543  * @key: storage key to use for storage access
544  * @expires: time span in jiffies after which to abort request
545  *
546  * Start the tcw on the given ccw device. Return zero on success, non-zero
547  * otherwise.
548  */
549 int ccw_device_tm_start_timeout_key(struct ccw_device *cdev, struct tcw *tcw,
550 				    unsigned long intparm, u8 lpm, u8 key,
551 				    int expires)
552 {
553 	int ret;
554 
555 	ccw_device_set_timeout(cdev, expires);
556 	ret = ccw_device_tm_start_key(cdev, tcw, intparm, lpm, key);
557 	if (ret != 0)
558 		ccw_device_set_timeout(cdev, 0);
559 	return ret;
560 }
561 EXPORT_SYMBOL(ccw_device_tm_start_timeout_key);
562 
563 /**
564  * ccw_device_tm_start() - perform start function
565  * @cdev: ccw device on which to perform the start function
566  * @tcw: transport-command word to be started
567  * @intparm: user defined parameter to be passed to the interrupt handler
568  * @lpm: mask of paths to use
569  *
570  * Start the tcw on the given ccw device. Return zero on success, non-zero
571  * otherwise.
572  */
573 int ccw_device_tm_start(struct ccw_device *cdev, struct tcw *tcw,
574 			unsigned long intparm, u8 lpm)
575 {
576 	return ccw_device_tm_start_key(cdev, tcw, intparm, lpm,
577 				       PAGE_DEFAULT_KEY);
578 }
579 EXPORT_SYMBOL(ccw_device_tm_start);
580 
581 /**
582  * ccw_device_tm_start_timeout() - perform start function
583  * @cdev: ccw device on which to perform the start function
584  * @tcw: transport-command word to be started
585  * @intparm: user defined parameter to be passed to the interrupt handler
586  * @lpm: mask of paths to use
587  * @expires: time span in jiffies after which to abort request
588  *
589  * Start the tcw on the given ccw device. Return zero on success, non-zero
590  * otherwise.
591  */
592 int ccw_device_tm_start_timeout(struct ccw_device *cdev, struct tcw *tcw,
593 			       unsigned long intparm, u8 lpm, int expires)
594 {
595 	return ccw_device_tm_start_timeout_key(cdev, tcw, intparm, lpm,
596 					       PAGE_DEFAULT_KEY, expires);
597 }
598 EXPORT_SYMBOL(ccw_device_tm_start_timeout);
599 
600 /**
601  * ccw_device_get_mdc() - accumulate max data count
602  * @cdev: ccw device for which the max data count is accumulated
603  * @mask: mask of paths to use
604  *
605  * Return the number of 64K-bytes blocks all paths at least support
606  * for a transport command. Return values <= 0 indicate failures.
607  */
608 int ccw_device_get_mdc(struct ccw_device *cdev, u8 mask)
609 {
610 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
611 	struct channel_path *chp;
612 	struct chp_id chpid;
613 	int mdc = 0, i;
614 
615 	/* Adjust requested path mask to excluded varied off paths. */
616 	if (mask)
617 		mask &= sch->lpm;
618 	else
619 		mask = sch->lpm;
620 
621 	chp_id_init(&chpid);
622 	for (i = 0; i < 8; i++) {
623 		if (!(mask & (0x80 >> i)))
624 			continue;
625 		chpid.id = sch->schib.pmcw.chpid[i];
626 		chp = chpid_to_chp(chpid);
627 		if (!chp)
628 			continue;
629 
630 		mutex_lock(&chp->lock);
631 		if (!chp->desc_fmt1.f) {
632 			mutex_unlock(&chp->lock);
633 			return 0;
634 		}
635 		if (!chp->desc_fmt1.r)
636 			mdc = 1;
637 		mdc = mdc ? min_t(int, mdc, chp->desc_fmt1.mdc) :
638 			    chp->desc_fmt1.mdc;
639 		mutex_unlock(&chp->lock);
640 	}
641 
642 	return mdc;
643 }
644 EXPORT_SYMBOL(ccw_device_get_mdc);
645 
646 /**
647  * ccw_device_tm_intrg() - perform interrogate function
648  * @cdev: ccw device on which to perform the interrogate function
649  *
650  * Perform an interrogate function on the given ccw device. Return zero on
651  * success, non-zero otherwise.
652  */
653 int ccw_device_tm_intrg(struct ccw_device *cdev)
654 {
655 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
656 
657 	if (!sch->schib.pmcw.ena)
658 		return -EINVAL;
659 	if (cdev->private->state != DEV_STATE_ONLINE)
660 		return -EIO;
661 	if (!scsw_is_tm(&sch->schib.scsw) ||
662 	    !(scsw_actl(&sch->schib.scsw) & SCSW_ACTL_START_PEND))
663 		return -EINVAL;
664 	return cio_tm_intrg(sch);
665 }
666 EXPORT_SYMBOL(ccw_device_tm_intrg);
667 
668 /**
669  * ccw_device_get_schid() - obtain a subchannel id
670  * @cdev: device to obtain the id for
671  * @schid: where to fill in the values
672  */
673 void ccw_device_get_schid(struct ccw_device *cdev, struct subchannel_id *schid)
674 {
675 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
676 
677 	*schid = sch->schid;
678 }
679 EXPORT_SYMBOL_GPL(ccw_device_get_schid);
680 
681 EXPORT_SYMBOL(ccw_device_set_options_mask);
682 EXPORT_SYMBOL(ccw_device_set_options);
683 EXPORT_SYMBOL(ccw_device_clear_options);
684 EXPORT_SYMBOL(ccw_device_clear);
685 EXPORT_SYMBOL(ccw_device_halt);
686 EXPORT_SYMBOL(ccw_device_resume);
687 EXPORT_SYMBOL(ccw_device_start_timeout);
688 EXPORT_SYMBOL(ccw_device_start);
689 EXPORT_SYMBOL(ccw_device_start_timeout_key);
690 EXPORT_SYMBOL(ccw_device_start_key);
691 EXPORT_SYMBOL(ccw_device_get_ciw);
692 EXPORT_SYMBOL(ccw_device_get_path_mask);
693 EXPORT_SYMBOL_GPL(ccw_device_get_chp_desc);
694