xref: /openbmc/linux/drivers/s390/char/sclp_cmd.c (revision 4800cd83)
1 /*
2  * Copyright IBM Corp. 2007, 2009
3  *
4  * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
5  *	      Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
6  */
7 
8 #define KMSG_COMPONENT "sclp_cmd"
9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
10 
11 #include <linux/completion.h>
12 #include <linux/init.h>
13 #include <linux/errno.h>
14 #include <linux/err.h>
15 #include <linux/slab.h>
16 #include <linux/string.h>
17 #include <linux/mm.h>
18 #include <linux/mmzone.h>
19 #include <linux/memory.h>
20 #include <linux/platform_device.h>
21 #include <asm/chpid.h>
22 #include <asm/sclp.h>
23 #include <asm/setup.h>
24 
25 #include "sclp.h"
26 
27 #define SCLP_CMDW_READ_SCP_INFO		0x00020001
28 #define SCLP_CMDW_READ_SCP_INFO_FORCED	0x00120001
29 
30 struct read_info_sccb {
31 	struct	sccb_header header;	/* 0-7 */
32 	u16	rnmax;			/* 8-9 */
33 	u8	rnsize;			/* 10 */
34 	u8	_reserved0[24 - 11];	/* 11-15 */
35 	u8	loadparm[8];		/* 24-31 */
36 	u8	_reserved1[48 - 32];	/* 32-47 */
37 	u64	facilities;		/* 48-55 */
38 	u8	_reserved2[84 - 56];	/* 56-83 */
39 	u8	fac84;			/* 84 */
40 	u8	_reserved3[91 - 85];	/* 85-90 */
41 	u8	flags;			/* 91 */
42 	u8	_reserved4[100 - 92];	/* 92-99 */
43 	u32	rnsize2;		/* 100-103 */
44 	u64	rnmax2;			/* 104-111 */
45 	u8	_reserved5[4096 - 112];	/* 112-4095 */
46 } __attribute__((packed, aligned(PAGE_SIZE)));
47 
48 static struct read_info_sccb __initdata early_read_info_sccb;
49 static int __initdata early_read_info_sccb_valid;
50 
51 u64 sclp_facilities;
52 static u8 sclp_fac84;
53 static unsigned long long rzm;
54 static unsigned long long rnmax;
55 
56 static int __init sclp_cmd_sync_early(sclp_cmdw_t cmd, void *sccb)
57 {
58 	int rc;
59 
60 	__ctl_set_bit(0, 9);
61 	rc = sclp_service_call(cmd, sccb);
62 	if (rc)
63 		goto out;
64 	__load_psw_mask(PSW_BASE_BITS | PSW_MASK_EXT |
65 			PSW_MASK_WAIT | PSW_DEFAULT_KEY);
66 	local_irq_disable();
67 out:
68 	/* Contents of the sccb might have changed. */
69 	barrier();
70 	__ctl_clear_bit(0, 9);
71 	return rc;
72 }
73 
74 static void __init sclp_read_info_early(void)
75 {
76 	int rc;
77 	int i;
78 	struct read_info_sccb *sccb;
79 	sclp_cmdw_t commands[] = {SCLP_CMDW_READ_SCP_INFO_FORCED,
80 				  SCLP_CMDW_READ_SCP_INFO};
81 
82 	sccb = &early_read_info_sccb;
83 	for (i = 0; i < ARRAY_SIZE(commands); i++) {
84 		do {
85 			memset(sccb, 0, sizeof(*sccb));
86 			sccb->header.length = sizeof(*sccb);
87 			sccb->header.function_code = 0x80;
88 			sccb->header.control_mask[2] = 0x80;
89 			rc = sclp_cmd_sync_early(commands[i], sccb);
90 		} while (rc == -EBUSY);
91 
92 		if (rc)
93 			break;
94 		if (sccb->header.response_code == 0x10) {
95 			early_read_info_sccb_valid = 1;
96 			break;
97 		}
98 		if (sccb->header.response_code != 0x1f0)
99 			break;
100 	}
101 }
102 
103 void __init sclp_facilities_detect(void)
104 {
105 	struct read_info_sccb *sccb;
106 
107 	sclp_read_info_early();
108 	if (!early_read_info_sccb_valid)
109 		return;
110 
111 	sccb = &early_read_info_sccb;
112 	sclp_facilities = sccb->facilities;
113 	sclp_fac84 = sccb->fac84;
114 	rnmax = sccb->rnmax ? sccb->rnmax : sccb->rnmax2;
115 	rzm = sccb->rnsize ? sccb->rnsize : sccb->rnsize2;
116 	rzm <<= 20;
117 }
118 
119 unsigned long long sclp_get_rnmax(void)
120 {
121 	return rnmax;
122 }
123 
124 unsigned long long sclp_get_rzm(void)
125 {
126 	return rzm;
127 }
128 
129 /*
130  * This function will be called after sclp_facilities_detect(), which gets
131  * called from early.c code. Therefore the sccb should have valid contents.
132  */
133 void __init sclp_get_ipl_info(struct sclp_ipl_info *info)
134 {
135 	struct read_info_sccb *sccb;
136 
137 	if (!early_read_info_sccb_valid)
138 		return;
139 	sccb = &early_read_info_sccb;
140 	info->is_valid = 1;
141 	if (sccb->flags & 0x2)
142 		info->has_dump = 1;
143 	memcpy(&info->loadparm, &sccb->loadparm, LOADPARM_LEN);
144 }
145 
146 static void sclp_sync_callback(struct sclp_req *req, void *data)
147 {
148 	struct completion *completion = data;
149 
150 	complete(completion);
151 }
152 
153 static int do_sync_request(sclp_cmdw_t cmd, void *sccb)
154 {
155 	struct completion completion;
156 	struct sclp_req *request;
157 	int rc;
158 
159 	request = kzalloc(sizeof(*request), GFP_KERNEL);
160 	if (!request)
161 		return -ENOMEM;
162 	request->command = cmd;
163 	request->sccb = sccb;
164 	request->status = SCLP_REQ_FILLED;
165 	request->callback = sclp_sync_callback;
166 	request->callback_data = &completion;
167 	init_completion(&completion);
168 
169 	/* Perform sclp request. */
170 	rc = sclp_add_request(request);
171 	if (rc)
172 		goto out;
173 	wait_for_completion(&completion);
174 
175 	/* Check response. */
176 	if (request->status != SCLP_REQ_DONE) {
177 		pr_warning("sync request failed (cmd=0x%08x, "
178 			   "status=0x%02x)\n", cmd, request->status);
179 		rc = -EIO;
180 	}
181 out:
182 	kfree(request);
183 	return rc;
184 }
185 
186 /*
187  * CPU configuration related functions.
188  */
189 
190 #define SCLP_CMDW_READ_CPU_INFO		0x00010001
191 #define SCLP_CMDW_CONFIGURE_CPU		0x00110001
192 #define SCLP_CMDW_DECONFIGURE_CPU	0x00100001
193 
194 struct read_cpu_info_sccb {
195 	struct	sccb_header header;
196 	u16	nr_configured;
197 	u16	offset_configured;
198 	u16	nr_standby;
199 	u16	offset_standby;
200 	u8	reserved[4096 - 16];
201 } __attribute__((packed, aligned(PAGE_SIZE)));
202 
203 static void sclp_fill_cpu_info(struct sclp_cpu_info *info,
204 			       struct read_cpu_info_sccb *sccb)
205 {
206 	char *page = (char *) sccb;
207 
208 	memset(info, 0, sizeof(*info));
209 	info->configured = sccb->nr_configured;
210 	info->standby = sccb->nr_standby;
211 	info->combined = sccb->nr_configured + sccb->nr_standby;
212 	info->has_cpu_type = sclp_fac84 & 0x1;
213 	memcpy(&info->cpu, page + sccb->offset_configured,
214 	       info->combined * sizeof(struct sclp_cpu_entry));
215 }
216 
217 int sclp_get_cpu_info(struct sclp_cpu_info *info)
218 {
219 	int rc;
220 	struct read_cpu_info_sccb *sccb;
221 
222 	if (!SCLP_HAS_CPU_INFO)
223 		return -EOPNOTSUPP;
224 	sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
225 	if (!sccb)
226 		return -ENOMEM;
227 	sccb->header.length = sizeof(*sccb);
228 	rc = do_sync_request(SCLP_CMDW_READ_CPU_INFO, sccb);
229 	if (rc)
230 		goto out;
231 	if (sccb->header.response_code != 0x0010) {
232 		pr_warning("readcpuinfo failed (response=0x%04x)\n",
233 			   sccb->header.response_code);
234 		rc = -EIO;
235 		goto out;
236 	}
237 	sclp_fill_cpu_info(info, sccb);
238 out:
239 	free_page((unsigned long) sccb);
240 	return rc;
241 }
242 
243 struct cpu_configure_sccb {
244 	struct sccb_header header;
245 } __attribute__((packed, aligned(8)));
246 
247 static int do_cpu_configure(sclp_cmdw_t cmd)
248 {
249 	struct cpu_configure_sccb *sccb;
250 	int rc;
251 
252 	if (!SCLP_HAS_CPU_RECONFIG)
253 		return -EOPNOTSUPP;
254 	/*
255 	 * This is not going to cross a page boundary since we force
256 	 * kmalloc to have a minimum alignment of 8 bytes on s390.
257 	 */
258 	sccb = kzalloc(sizeof(*sccb), GFP_KERNEL | GFP_DMA);
259 	if (!sccb)
260 		return -ENOMEM;
261 	sccb->header.length = sizeof(*sccb);
262 	rc = do_sync_request(cmd, sccb);
263 	if (rc)
264 		goto out;
265 	switch (sccb->header.response_code) {
266 	case 0x0020:
267 	case 0x0120:
268 		break;
269 	default:
270 		pr_warning("configure cpu failed (cmd=0x%08x, "
271 			   "response=0x%04x)\n", cmd,
272 			   sccb->header.response_code);
273 		rc = -EIO;
274 		break;
275 	}
276 out:
277 	kfree(sccb);
278 	return rc;
279 }
280 
281 int sclp_cpu_configure(u8 cpu)
282 {
283 	return do_cpu_configure(SCLP_CMDW_CONFIGURE_CPU | cpu << 8);
284 }
285 
286 int sclp_cpu_deconfigure(u8 cpu)
287 {
288 	return do_cpu_configure(SCLP_CMDW_DECONFIGURE_CPU | cpu << 8);
289 }
290 
291 #ifdef CONFIG_MEMORY_HOTPLUG
292 
293 static DEFINE_MUTEX(sclp_mem_mutex);
294 static LIST_HEAD(sclp_mem_list);
295 static u8 sclp_max_storage_id;
296 static unsigned long sclp_storage_ids[256 / BITS_PER_LONG];
297 static int sclp_mem_state_changed;
298 
299 struct memory_increment {
300 	struct list_head list;
301 	u16 rn;
302 	int standby;
303 	int usecount;
304 };
305 
306 struct assign_storage_sccb {
307 	struct sccb_header header;
308 	u16 rn;
309 } __packed;
310 
311 int arch_get_memory_phys_device(unsigned long start_pfn)
312 {
313 	if (!rzm)
314 		return 0;
315 	return PFN_PHYS(start_pfn) >> ilog2(rzm);
316 }
317 
318 static unsigned long long rn2addr(u16 rn)
319 {
320 	return (unsigned long long) (rn - 1) * rzm;
321 }
322 
323 static int do_assign_storage(sclp_cmdw_t cmd, u16 rn)
324 {
325 	struct assign_storage_sccb *sccb;
326 	int rc;
327 
328 	sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
329 	if (!sccb)
330 		return -ENOMEM;
331 	sccb->header.length = PAGE_SIZE;
332 	sccb->rn = rn;
333 	rc = do_sync_request(cmd, sccb);
334 	if (rc)
335 		goto out;
336 	switch (sccb->header.response_code) {
337 	case 0x0020:
338 	case 0x0120:
339 		break;
340 	default:
341 		pr_warning("assign storage failed (cmd=0x%08x, "
342 			   "response=0x%04x, rn=0x%04x)\n", cmd,
343 			   sccb->header.response_code, rn);
344 		rc = -EIO;
345 		break;
346 	}
347 out:
348 	free_page((unsigned long) sccb);
349 	return rc;
350 }
351 
352 static int sclp_assign_storage(u16 rn)
353 {
354 	return do_assign_storage(0x000d0001, rn);
355 }
356 
357 static int sclp_unassign_storage(u16 rn)
358 {
359 	return do_assign_storage(0x000c0001, rn);
360 }
361 
362 struct attach_storage_sccb {
363 	struct sccb_header header;
364 	u16 :16;
365 	u16 assigned;
366 	u32 :32;
367 	u32 entries[0];
368 } __packed;
369 
370 static int sclp_attach_storage(u8 id)
371 {
372 	struct attach_storage_sccb *sccb;
373 	int rc;
374 	int i;
375 
376 	sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
377 	if (!sccb)
378 		return -ENOMEM;
379 	sccb->header.length = PAGE_SIZE;
380 	rc = do_sync_request(0x00080001 | id << 8, sccb);
381 	if (rc)
382 		goto out;
383 	switch (sccb->header.response_code) {
384 	case 0x0020:
385 		set_bit(id, sclp_storage_ids);
386 		for (i = 0; i < sccb->assigned; i++)
387 			sclp_unassign_storage(sccb->entries[i] >> 16);
388 		break;
389 	default:
390 		rc = -EIO;
391 		break;
392 	}
393 out:
394 	free_page((unsigned long) sccb);
395 	return rc;
396 }
397 
398 static int sclp_mem_change_state(unsigned long start, unsigned long size,
399 				 int online)
400 {
401 	struct memory_increment *incr;
402 	unsigned long long istart;
403 	int rc = 0;
404 
405 	list_for_each_entry(incr, &sclp_mem_list, list) {
406 		istart = rn2addr(incr->rn);
407 		if (start + size - 1 < istart)
408 			break;
409 		if (start > istart + rzm - 1)
410 			continue;
411 		if (online) {
412 			if (incr->usecount++)
413 				continue;
414 			/*
415 			 * Don't break the loop if one assign fails. Loop may
416 			 * be walked again on CANCEL and we can't save
417 			 * information if state changed before or not.
418 			 * So continue and increase usecount for all increments.
419 			 */
420 			rc |= sclp_assign_storage(incr->rn);
421 		} else {
422 			if (--incr->usecount)
423 				continue;
424 			sclp_unassign_storage(incr->rn);
425 		}
426 	}
427 	return rc ? -EIO : 0;
428 }
429 
430 static int sclp_mem_notifier(struct notifier_block *nb,
431 			     unsigned long action, void *data)
432 {
433 	unsigned long start, size;
434 	struct memory_notify *arg;
435 	unsigned char id;
436 	int rc = 0;
437 
438 	arg = data;
439 	start = arg->start_pfn << PAGE_SHIFT;
440 	size = arg->nr_pages << PAGE_SHIFT;
441 	mutex_lock(&sclp_mem_mutex);
442 	for (id = 0; id <= sclp_max_storage_id; id++)
443 		if (!test_bit(id, sclp_storage_ids))
444 			sclp_attach_storage(id);
445 	switch (action) {
446 	case MEM_ONLINE:
447 	case MEM_GOING_OFFLINE:
448 	case MEM_CANCEL_OFFLINE:
449 		break;
450 	case MEM_GOING_ONLINE:
451 		rc = sclp_mem_change_state(start, size, 1);
452 		break;
453 	case MEM_CANCEL_ONLINE:
454 		sclp_mem_change_state(start, size, 0);
455 		break;
456 	case MEM_OFFLINE:
457 		sclp_mem_change_state(start, size, 0);
458 		break;
459 	default:
460 		rc = -EINVAL;
461 		break;
462 	}
463 	if (!rc)
464 		sclp_mem_state_changed = 1;
465 	mutex_unlock(&sclp_mem_mutex);
466 	return rc ? NOTIFY_BAD : NOTIFY_OK;
467 }
468 
469 static struct notifier_block sclp_mem_nb = {
470 	.notifier_call = sclp_mem_notifier,
471 };
472 
473 static void __init add_memory_merged(u16 rn)
474 {
475 	static u16 first_rn, num;
476 	unsigned long long start, size;
477 
478 	if (rn && first_rn && (first_rn + num == rn)) {
479 		num++;
480 		return;
481 	}
482 	if (!first_rn)
483 		goto skip_add;
484 	start = rn2addr(first_rn);
485 	size = (unsigned long long ) num * rzm;
486 	if (start >= VMEM_MAX_PHYS)
487 		goto skip_add;
488 	if (start + size > VMEM_MAX_PHYS)
489 		size = VMEM_MAX_PHYS - start;
490 	if (memory_end_set && (start >= memory_end))
491 		goto skip_add;
492 	if (memory_end_set && (start + size > memory_end))
493 		size = memory_end - start;
494 	add_memory(0, start, size);
495 skip_add:
496 	first_rn = rn;
497 	num = 1;
498 }
499 
500 static void __init sclp_add_standby_memory(void)
501 {
502 	struct memory_increment *incr;
503 
504 	list_for_each_entry(incr, &sclp_mem_list, list)
505 		if (incr->standby)
506 			add_memory_merged(incr->rn);
507 	add_memory_merged(0);
508 }
509 
510 static void __init insert_increment(u16 rn, int standby, int assigned)
511 {
512 	struct memory_increment *incr, *new_incr;
513 	struct list_head *prev;
514 	u16 last_rn;
515 
516 	new_incr = kzalloc(sizeof(*new_incr), GFP_KERNEL);
517 	if (!new_incr)
518 		return;
519 	new_incr->rn = rn;
520 	new_incr->standby = standby;
521 	last_rn = 0;
522 	prev = &sclp_mem_list;
523 	list_for_each_entry(incr, &sclp_mem_list, list) {
524 		if (assigned && incr->rn > rn)
525 			break;
526 		if (!assigned && incr->rn - last_rn > 1)
527 			break;
528 		last_rn = incr->rn;
529 		prev = &incr->list;
530 	}
531 	if (!assigned)
532 		new_incr->rn = last_rn + 1;
533 	if (new_incr->rn > rnmax) {
534 		kfree(new_incr);
535 		return;
536 	}
537 	list_add(&new_incr->list, prev);
538 }
539 
540 static int sclp_mem_freeze(struct device *dev)
541 {
542 	if (!sclp_mem_state_changed)
543 		return 0;
544 	pr_err("Memory hotplug state changed, suspend refused.\n");
545 	return -EPERM;
546 }
547 
548 struct read_storage_sccb {
549 	struct sccb_header header;
550 	u16 max_id;
551 	u16 assigned;
552 	u16 standby;
553 	u16 :16;
554 	u32 entries[0];
555 } __packed;
556 
557 static const struct dev_pm_ops sclp_mem_pm_ops = {
558 	.freeze		= sclp_mem_freeze,
559 };
560 
561 static struct platform_driver sclp_mem_pdrv = {
562 	.driver = {
563 		.name	= "sclp_mem",
564 		.pm	= &sclp_mem_pm_ops,
565 	},
566 };
567 
568 static int __init sclp_detect_standby_memory(void)
569 {
570 	struct platform_device *sclp_pdev;
571 	struct read_storage_sccb *sccb;
572 	int i, id, assigned, rc;
573 
574 	if (!early_read_info_sccb_valid)
575 		return 0;
576 	if ((sclp_facilities & 0xe00000000000ULL) != 0xe00000000000ULL)
577 		return 0;
578 	rc = -ENOMEM;
579 	sccb = (void *) __get_free_page(GFP_KERNEL | GFP_DMA);
580 	if (!sccb)
581 		goto out;
582 	assigned = 0;
583 	for (id = 0; id <= sclp_max_storage_id; id++) {
584 		memset(sccb, 0, PAGE_SIZE);
585 		sccb->header.length = PAGE_SIZE;
586 		rc = do_sync_request(0x00040001 | id << 8, sccb);
587 		if (rc)
588 			goto out;
589 		switch (sccb->header.response_code) {
590 		case 0x0010:
591 			set_bit(id, sclp_storage_ids);
592 			for (i = 0; i < sccb->assigned; i++) {
593 				if (!sccb->entries[i])
594 					continue;
595 				assigned++;
596 				insert_increment(sccb->entries[i] >> 16, 0, 1);
597 			}
598 			break;
599 		case 0x0310:
600 			break;
601 		case 0x0410:
602 			for (i = 0; i < sccb->assigned; i++) {
603 				if (!sccb->entries[i])
604 					continue;
605 				assigned++;
606 				insert_increment(sccb->entries[i] >> 16, 1, 1);
607 			}
608 			break;
609 		default:
610 			rc = -EIO;
611 			break;
612 		}
613 		if (!rc)
614 			sclp_max_storage_id = sccb->max_id;
615 	}
616 	if (rc || list_empty(&sclp_mem_list))
617 		goto out;
618 	for (i = 1; i <= rnmax - assigned; i++)
619 		insert_increment(0, 1, 0);
620 	rc = register_memory_notifier(&sclp_mem_nb);
621 	if (rc)
622 		goto out;
623 	rc = platform_driver_register(&sclp_mem_pdrv);
624 	if (rc)
625 		goto out;
626 	sclp_pdev = platform_device_register_simple("sclp_mem", -1, NULL, 0);
627 	rc = IS_ERR(sclp_pdev) ? PTR_ERR(sclp_pdev) : 0;
628 	if (rc)
629 		goto out_driver;
630 	sclp_add_standby_memory();
631 	goto out;
632 out_driver:
633 	platform_driver_unregister(&sclp_mem_pdrv);
634 out:
635 	free_page((unsigned long) sccb);
636 	return rc;
637 }
638 __initcall(sclp_detect_standby_memory);
639 
640 #endif /* CONFIG_MEMORY_HOTPLUG */
641 
642 /*
643  * Channel path configuration related functions.
644  */
645 
646 #define SCLP_CMDW_CONFIGURE_CHPATH		0x000f0001
647 #define SCLP_CMDW_DECONFIGURE_CHPATH		0x000e0001
648 #define SCLP_CMDW_READ_CHPATH_INFORMATION	0x00030001
649 
650 struct chp_cfg_sccb {
651 	struct sccb_header header;
652 	u8 ccm;
653 	u8 reserved[6];
654 	u8 cssid;
655 } __attribute__((packed));
656 
657 static int do_chp_configure(sclp_cmdw_t cmd)
658 {
659 	struct chp_cfg_sccb *sccb;
660 	int rc;
661 
662 	if (!SCLP_HAS_CHP_RECONFIG)
663 		return -EOPNOTSUPP;
664 	/* Prepare sccb. */
665 	sccb = (struct chp_cfg_sccb *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
666 	if (!sccb)
667 		return -ENOMEM;
668 	sccb->header.length = sizeof(*sccb);
669 	rc = do_sync_request(cmd, sccb);
670 	if (rc)
671 		goto out;
672 	switch (sccb->header.response_code) {
673 	case 0x0020:
674 	case 0x0120:
675 	case 0x0440:
676 	case 0x0450:
677 		break;
678 	default:
679 		pr_warning("configure channel-path failed "
680 			   "(cmd=0x%08x, response=0x%04x)\n", cmd,
681 			   sccb->header.response_code);
682 		rc = -EIO;
683 		break;
684 	}
685 out:
686 	free_page((unsigned long) sccb);
687 	return rc;
688 }
689 
690 /**
691  * sclp_chp_configure - perform configure channel-path sclp command
692  * @chpid: channel-path ID
693  *
694  * Perform configure channel-path command sclp command for specified chpid.
695  * Return 0 after command successfully finished, non-zero otherwise.
696  */
697 int sclp_chp_configure(struct chp_id chpid)
698 {
699 	return do_chp_configure(SCLP_CMDW_CONFIGURE_CHPATH | chpid.id << 8);
700 }
701 
702 /**
703  * sclp_chp_deconfigure - perform deconfigure channel-path sclp command
704  * @chpid: channel-path ID
705  *
706  * Perform deconfigure channel-path command sclp command for specified chpid
707  * and wait for completion. On success return 0. Return non-zero otherwise.
708  */
709 int sclp_chp_deconfigure(struct chp_id chpid)
710 {
711 	return do_chp_configure(SCLP_CMDW_DECONFIGURE_CHPATH | chpid.id << 8);
712 }
713 
714 struct chp_info_sccb {
715 	struct sccb_header header;
716 	u8 recognized[SCLP_CHP_INFO_MASK_SIZE];
717 	u8 standby[SCLP_CHP_INFO_MASK_SIZE];
718 	u8 configured[SCLP_CHP_INFO_MASK_SIZE];
719 	u8 ccm;
720 	u8 reserved[6];
721 	u8 cssid;
722 } __attribute__((packed));
723 
724 /**
725  * sclp_chp_read_info - perform read channel-path information sclp command
726  * @info: resulting channel-path information data
727  *
728  * Perform read channel-path information sclp command and wait for completion.
729  * On success, store channel-path information in @info and return 0. Return
730  * non-zero otherwise.
731  */
732 int sclp_chp_read_info(struct sclp_chp_info *info)
733 {
734 	struct chp_info_sccb *sccb;
735 	int rc;
736 
737 	if (!SCLP_HAS_CHP_INFO)
738 		return -EOPNOTSUPP;
739 	/* Prepare sccb. */
740 	sccb = (struct chp_info_sccb *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
741 	if (!sccb)
742 		return -ENOMEM;
743 	sccb->header.length = sizeof(*sccb);
744 	rc = do_sync_request(SCLP_CMDW_READ_CHPATH_INFORMATION, sccb);
745 	if (rc)
746 		goto out;
747 	if (sccb->header.response_code != 0x0010) {
748 		pr_warning("read channel-path info failed "
749 			   "(response=0x%04x)\n", sccb->header.response_code);
750 		rc = -EIO;
751 		goto out;
752 	}
753 	memcpy(info->recognized, sccb->recognized, SCLP_CHP_INFO_MASK_SIZE);
754 	memcpy(info->standby, sccb->standby, SCLP_CHP_INFO_MASK_SIZE);
755 	memcpy(info->configured, sccb->configured, SCLP_CHP_INFO_MASK_SIZE);
756 out:
757 	free_page((unsigned long) sccb);
758 	return rc;
759 }
760