[S390] sclp/memory hotplug: fix initial usecount of increments
[linux-2.6.git] / drivers / s390 / char / sclp_cmd.c
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         if (!standby)
522                 new_incr->usecount = 1;
523         last_rn = 0;
524         prev = &sclp_mem_list;
525         list_for_each_entry(incr, &sclp_mem_list, list) {
526                 if (assigned && incr->rn > rn)
527                         break;
528                 if (!assigned && incr->rn - last_rn > 1)
529                         break;
530                 last_rn = incr->rn;
531                 prev = &incr->list;
532         }
533         if (!assigned)
534                 new_incr->rn = last_rn + 1;
535         if (new_incr->rn > rnmax) {
536                 kfree(new_incr);
537                 return;
538         }
539         list_add(&new_incr->list, prev);
540 }
541
542 static int sclp_mem_freeze(struct device *dev)
543 {
544         if (!sclp_mem_state_changed)
545                 return 0;
546         pr_err("Memory hotplug state changed, suspend refused.\n");
547         return -EPERM;
548 }
549
550 struct read_storage_sccb {
551         struct sccb_header header;
552         u16 max_id;
553         u16 assigned;
554         u16 standby;
555         u16 :16;
556         u32 entries[0];
557 } __packed;
558
559 static const struct dev_pm_ops sclp_mem_pm_ops = {
560         .freeze         = sclp_mem_freeze,
561 };
562
563 static struct platform_driver sclp_mem_pdrv = {
564         .driver = {
565                 .name   = "sclp_mem",
566                 .pm     = &sclp_mem_pm_ops,
567         },
568 };
569
570 static int __init sclp_detect_standby_memory(void)
571 {
572         struct platform_device *sclp_pdev;
573         struct read_storage_sccb *sccb;
574         int i, id, assigned, rc;
575
576         if (!early_read_info_sccb_valid)
577                 return 0;
578         if ((sclp_facilities & 0xe00000000000ULL) != 0xe00000000000ULL)
579                 return 0;
580         rc = -ENOMEM;
581         sccb = (void *) __get_free_page(GFP_KERNEL | GFP_DMA);
582         if (!sccb)
583                 goto out;
584         assigned = 0;
585         for (id = 0; id <= sclp_max_storage_id; id++) {
586                 memset(sccb, 0, PAGE_SIZE);
587                 sccb->header.length = PAGE_SIZE;
588                 rc = do_sync_request(0x00040001 | id << 8, sccb);
589                 if (rc)
590                         goto out;
591                 switch (sccb->header.response_code) {
592                 case 0x0010:
593                         set_bit(id, sclp_storage_ids);
594                         for (i = 0; i < sccb->assigned; i++) {
595                                 if (!sccb->entries[i])
596                                         continue;
597                                 assigned++;
598                                 insert_increment(sccb->entries[i] >> 16, 0, 1);
599                         }
600                         break;
601                 case 0x0310:
602                         break;
603                 case 0x0410:
604                         for (i = 0; i < sccb->assigned; i++) {
605                                 if (!sccb->entries[i])
606                                         continue;
607                                 assigned++;
608                                 insert_increment(sccb->entries[i] >> 16, 1, 1);
609                         }
610                         break;
611                 default:
612                         rc = -EIO;
613                         break;
614                 }
615                 if (!rc)
616                         sclp_max_storage_id = sccb->max_id;
617         }
618         if (rc || list_empty(&sclp_mem_list))
619                 goto out;
620         for (i = 1; i <= rnmax - assigned; i++)
621                 insert_increment(0, 1, 0);
622         rc = register_memory_notifier(&sclp_mem_nb);
623         if (rc)
624                 goto out;
625         rc = platform_driver_register(&sclp_mem_pdrv);
626         if (rc)
627                 goto out;
628         sclp_pdev = platform_device_register_simple("sclp_mem", -1, NULL, 0);
629         rc = IS_ERR(sclp_pdev) ? PTR_ERR(sclp_pdev) : 0;
630         if (rc)
631                 goto out_driver;
632         sclp_add_standby_memory();
633         goto out;
634 out_driver:
635         platform_driver_unregister(&sclp_mem_pdrv);
636 out:
637         free_page((unsigned long) sccb);
638         return rc;
639 }
640 __initcall(sclp_detect_standby_memory);
641
642 #endif /* CONFIG_MEMORY_HOTPLUG */
643
644 /*
645  * Channel path configuration related functions.
646  */
647
648 #define SCLP_CMDW_CONFIGURE_CHPATH              0x000f0001
649 #define SCLP_CMDW_DECONFIGURE_CHPATH            0x000e0001
650 #define SCLP_CMDW_READ_CHPATH_INFORMATION       0x00030001
651
652 struct chp_cfg_sccb {
653         struct sccb_header header;
654         u8 ccm;
655         u8 reserved[6];
656         u8 cssid;
657 } __attribute__((packed));
658
659 static int do_chp_configure(sclp_cmdw_t cmd)
660 {
661         struct chp_cfg_sccb *sccb;
662         int rc;
663
664         if (!SCLP_HAS_CHP_RECONFIG)
665                 return -EOPNOTSUPP;
666         /* Prepare sccb. */
667         sccb = (struct chp_cfg_sccb *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
668         if (!sccb)
669                 return -ENOMEM;
670         sccb->header.length = sizeof(*sccb);
671         rc = do_sync_request(cmd, sccb);
672         if (rc)
673                 goto out;
674         switch (sccb->header.response_code) {
675         case 0x0020:
676         case 0x0120:
677         case 0x0440:
678         case 0x0450:
679                 break;
680         default:
681                 pr_warning("configure channel-path failed "
682                            "(cmd=0x%08x, response=0x%04x)\n", cmd,
683                            sccb->header.response_code);
684                 rc = -EIO;
685                 break;
686         }
687 out:
688         free_page((unsigned long) sccb);
689         return rc;
690 }
691
692 /**
693  * sclp_chp_configure - perform configure channel-path sclp command
694  * @chpid: channel-path ID
695  *
696  * Perform configure channel-path command sclp command for specified chpid.
697  * Return 0 after command successfully finished, non-zero otherwise.
698  */
699 int sclp_chp_configure(struct chp_id chpid)
700 {
701         return do_chp_configure(SCLP_CMDW_CONFIGURE_CHPATH | chpid.id << 8);
702 }
703
704 /**
705  * sclp_chp_deconfigure - perform deconfigure channel-path sclp command
706  * @chpid: channel-path ID
707  *
708  * Perform deconfigure channel-path command sclp command for specified chpid
709  * and wait for completion. On success return 0. Return non-zero otherwise.
710  */
711 int sclp_chp_deconfigure(struct chp_id chpid)
712 {
713         return do_chp_configure(SCLP_CMDW_DECONFIGURE_CHPATH | chpid.id << 8);
714 }
715
716 struct chp_info_sccb {
717         struct sccb_header header;
718         u8 recognized[SCLP_CHP_INFO_MASK_SIZE];
719         u8 standby[SCLP_CHP_INFO_MASK_SIZE];
720         u8 configured[SCLP_CHP_INFO_MASK_SIZE];
721         u8 ccm;
722         u8 reserved[6];
723         u8 cssid;
724 } __attribute__((packed));
725
726 /**
727  * sclp_chp_read_info - perform read channel-path information sclp command
728  * @info: resulting channel-path information data
729  *
730  * Perform read channel-path information sclp command and wait for completion.
731  * On success, store channel-path information in @info and return 0. Return
732  * non-zero otherwise.
733  */
734 int sclp_chp_read_info(struct sclp_chp_info *info)
735 {
736         struct chp_info_sccb *sccb;
737         int rc;
738
739         if (!SCLP_HAS_CHP_INFO)
740                 return -EOPNOTSUPP;
741         /* Prepare sccb. */
742         sccb = (struct chp_info_sccb *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
743         if (!sccb)
744                 return -ENOMEM;
745         sccb->header.length = sizeof(*sccb);
746         rc = do_sync_request(SCLP_CMDW_READ_CHPATH_INFORMATION, sccb);
747         if (rc)
748                 goto out;
749         if (sccb->header.response_code != 0x0010) {
750                 pr_warning("read channel-path info failed "
751                            "(response=0x%04x)\n", sccb->header.response_code);
752                 rc = -EIO;
753                 goto out;
754         }
755         memcpy(info->recognized, sccb->recognized, SCLP_CHP_INFO_MASK_SIZE);
756         memcpy(info->standby, sccb->standby, SCLP_CHP_INFO_MASK_SIZE);
757         memcpy(info->configured, sccb->configured, SCLP_CHP_INFO_MASK_SIZE);
758 out:
759         free_page((unsigned long) sccb);
760         return rc;
761 }