Merge tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm...
[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 #include <asm/ctl_reg.h>
25
26 #include "sclp.h"
27
28 #define SCLP_CMDW_READ_SCP_INFO         0x00020001
29 #define SCLP_CMDW_READ_SCP_INFO_FORCED  0x00120001
30
31 struct read_info_sccb {
32         struct  sccb_header header;     /* 0-7 */
33         u16     rnmax;                  /* 8-9 */
34         u8      rnsize;                 /* 10 */
35         u8      _reserved0[24 - 11];    /* 11-15 */
36         u8      loadparm[8];            /* 24-31 */
37         u8      _reserved1[48 - 32];    /* 32-47 */
38         u64     facilities;             /* 48-55 */
39         u8      _reserved2[84 - 56];    /* 56-83 */
40         u8      fac84;                  /* 84 */
41         u8      _reserved3[91 - 85];    /* 85-90 */
42         u8      flags;                  /* 91 */
43         u8      _reserved4[100 - 92];   /* 92-99 */
44         u32     rnsize2;                /* 100-103 */
45         u64     rnmax2;                 /* 104-111 */
46         u8      _reserved5[4096 - 112]; /* 112-4095 */
47 } __attribute__((packed, aligned(PAGE_SIZE)));
48
49 static struct read_info_sccb __initdata early_read_info_sccb;
50 static int __initdata early_read_info_sccb_valid;
51
52 u64 sclp_facilities;
53 static u8 sclp_fac84;
54 static unsigned long long rzm;
55 static unsigned long long rnmax;
56
57 static int __init sclp_cmd_sync_early(sclp_cmdw_t cmd, void *sccb)
58 {
59         int rc;
60
61         __ctl_set_bit(0, 9);
62         rc = sclp_service_call(cmd, sccb);
63         if (rc)
64                 goto out;
65         __load_psw_mask(PSW_DEFAULT_KEY | PSW_MASK_BASE | PSW_MASK_EA |
66                         PSW_MASK_BA | PSW_MASK_EXT | PSW_MASK_WAIT);
67         local_irq_disable();
68 out:
69         /* Contents of the sccb might have changed. */
70         barrier();
71         __ctl_clear_bit(0, 9);
72         return rc;
73 }
74
75 static void __init sclp_read_info_early(void)
76 {
77         int rc;
78         int i;
79         struct read_info_sccb *sccb;
80         sclp_cmdw_t commands[] = {SCLP_CMDW_READ_SCP_INFO_FORCED,
81                                   SCLP_CMDW_READ_SCP_INFO};
82
83         sccb = &early_read_info_sccb;
84         for (i = 0; i < ARRAY_SIZE(commands); i++) {
85                 do {
86                         memset(sccb, 0, sizeof(*sccb));
87                         sccb->header.length = sizeof(*sccb);
88                         sccb->header.function_code = 0x80;
89                         sccb->header.control_mask[2] = 0x80;
90                         rc = sclp_cmd_sync_early(commands[i], sccb);
91                 } while (rc == -EBUSY);
92
93                 if (rc)
94                         break;
95                 if (sccb->header.response_code == 0x10) {
96                         early_read_info_sccb_valid = 1;
97                         break;
98                 }
99                 if (sccb->header.response_code != 0x1f0)
100                         break;
101         }
102 }
103
104 void __init sclp_facilities_detect(void)
105 {
106         struct read_info_sccb *sccb;
107
108         sclp_read_info_early();
109         if (!early_read_info_sccb_valid)
110                 return;
111
112         sccb = &early_read_info_sccb;
113         sclp_facilities = sccb->facilities;
114         sclp_fac84 = sccb->fac84;
115         rnmax = sccb->rnmax ? sccb->rnmax : sccb->rnmax2;
116         rzm = sccb->rnsize ? sccb->rnsize : sccb->rnsize2;
117         rzm <<= 20;
118 }
119
120 unsigned long long sclp_get_rnmax(void)
121 {
122         return rnmax;
123 }
124
125 unsigned long long sclp_get_rzm(void)
126 {
127         return rzm;
128 }
129
130 /*
131  * This function will be called after sclp_facilities_detect(), which gets
132  * called from early.c code. Therefore the sccb should have valid contents.
133  */
134 void __init sclp_get_ipl_info(struct sclp_ipl_info *info)
135 {
136         struct read_info_sccb *sccb;
137
138         if (!early_read_info_sccb_valid)
139                 return;
140         sccb = &early_read_info_sccb;
141         info->is_valid = 1;
142         if (sccb->flags & 0x2)
143                 info->has_dump = 1;
144         memcpy(&info->loadparm, &sccb->loadparm, LOADPARM_LEN);
145 }
146
147 static void sclp_sync_callback(struct sclp_req *req, void *data)
148 {
149         struct completion *completion = data;
150
151         complete(completion);
152 }
153
154 static int do_sync_request(sclp_cmdw_t cmd, void *sccb)
155 {
156         struct completion completion;
157         struct sclp_req *request;
158         int rc;
159
160         request = kzalloc(sizeof(*request), GFP_KERNEL);
161         if (!request)
162                 return -ENOMEM;
163         request->command = cmd;
164         request->sccb = sccb;
165         request->status = SCLP_REQ_FILLED;
166         request->callback = sclp_sync_callback;
167         request->callback_data = &completion;
168         init_completion(&completion);
169
170         /* Perform sclp request. */
171         rc = sclp_add_request(request);
172         if (rc)
173                 goto out;
174         wait_for_completion(&completion);
175
176         /* Check response. */
177         if (request->status != SCLP_REQ_DONE) {
178                 pr_warning("sync request failed (cmd=0x%08x, "
179                            "status=0x%02x)\n", cmd, request->status);
180                 rc = -EIO;
181         }
182 out:
183         kfree(request);
184         return rc;
185 }
186
187 /*
188  * CPU configuration related functions.
189  */
190
191 #define SCLP_CMDW_READ_CPU_INFO         0x00010001
192 #define SCLP_CMDW_CONFIGURE_CPU         0x00110001
193 #define SCLP_CMDW_DECONFIGURE_CPU       0x00100001
194
195 struct read_cpu_info_sccb {
196         struct  sccb_header header;
197         u16     nr_configured;
198         u16     offset_configured;
199         u16     nr_standby;
200         u16     offset_standby;
201         u8      reserved[4096 - 16];
202 } __attribute__((packed, aligned(PAGE_SIZE)));
203
204 static void sclp_fill_cpu_info(struct sclp_cpu_info *info,
205                                struct read_cpu_info_sccb *sccb)
206 {
207         char *page = (char *) sccb;
208
209         memset(info, 0, sizeof(*info));
210         info->configured = sccb->nr_configured;
211         info->standby = sccb->nr_standby;
212         info->combined = sccb->nr_configured + sccb->nr_standby;
213         info->has_cpu_type = sclp_fac84 & 0x1;
214         memcpy(&info->cpu, page + sccb->offset_configured,
215                info->combined * sizeof(struct sclp_cpu_entry));
216 }
217
218 int sclp_get_cpu_info(struct sclp_cpu_info *info)
219 {
220         int rc;
221         struct read_cpu_info_sccb *sccb;
222
223         if (!SCLP_HAS_CPU_INFO)
224                 return -EOPNOTSUPP;
225         sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
226         if (!sccb)
227                 return -ENOMEM;
228         sccb->header.length = sizeof(*sccb);
229         rc = do_sync_request(SCLP_CMDW_READ_CPU_INFO, sccb);
230         if (rc)
231                 goto out;
232         if (sccb->header.response_code != 0x0010) {
233                 pr_warning("readcpuinfo failed (response=0x%04x)\n",
234                            sccb->header.response_code);
235                 rc = -EIO;
236                 goto out;
237         }
238         sclp_fill_cpu_info(info, sccb);
239 out:
240         free_page((unsigned long) sccb);
241         return rc;
242 }
243
244 struct cpu_configure_sccb {
245         struct sccb_header header;
246 } __attribute__((packed, aligned(8)));
247
248 static int do_cpu_configure(sclp_cmdw_t cmd)
249 {
250         struct cpu_configure_sccb *sccb;
251         int rc;
252
253         if (!SCLP_HAS_CPU_RECONFIG)
254                 return -EOPNOTSUPP;
255         /*
256          * This is not going to cross a page boundary since we force
257          * kmalloc to have a minimum alignment of 8 bytes on s390.
258          */
259         sccb = kzalloc(sizeof(*sccb), GFP_KERNEL | GFP_DMA);
260         if (!sccb)
261                 return -ENOMEM;
262         sccb->header.length = sizeof(*sccb);
263         rc = do_sync_request(cmd, sccb);
264         if (rc)
265                 goto out;
266         switch (sccb->header.response_code) {
267         case 0x0020:
268         case 0x0120:
269                 break;
270         default:
271                 pr_warning("configure cpu failed (cmd=0x%08x, "
272                            "response=0x%04x)\n", cmd,
273                            sccb->header.response_code);
274                 rc = -EIO;
275                 break;
276         }
277 out:
278         kfree(sccb);
279         return rc;
280 }
281
282 int sclp_cpu_configure(u8 cpu)
283 {
284         return do_cpu_configure(SCLP_CMDW_CONFIGURE_CPU | cpu << 8);
285 }
286
287 int sclp_cpu_deconfigure(u8 cpu)
288 {
289         return do_cpu_configure(SCLP_CMDW_DECONFIGURE_CPU | cpu << 8);
290 }
291
292 #ifdef CONFIG_MEMORY_HOTPLUG
293
294 static DEFINE_MUTEX(sclp_mem_mutex);
295 static LIST_HEAD(sclp_mem_list);
296 static u8 sclp_max_storage_id;
297 static unsigned long sclp_storage_ids[256 / BITS_PER_LONG];
298 static int sclp_mem_state_changed;
299
300 struct memory_increment {
301         struct list_head list;
302         u16 rn;
303         int standby;
304         int usecount;
305 };
306
307 struct assign_storage_sccb {
308         struct sccb_header header;
309         u16 rn;
310 } __packed;
311
312 int arch_get_memory_phys_device(unsigned long start_pfn)
313 {
314         if (!rzm)
315                 return 0;
316         return PFN_PHYS(start_pfn) >> ilog2(rzm);
317 }
318
319 static unsigned long long rn2addr(u16 rn)
320 {
321         return (unsigned long long) (rn - 1) * rzm;
322 }
323
324 static int do_assign_storage(sclp_cmdw_t cmd, u16 rn)
325 {
326         struct assign_storage_sccb *sccb;
327         int rc;
328
329         sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
330         if (!sccb)
331                 return -ENOMEM;
332         sccb->header.length = PAGE_SIZE;
333         sccb->rn = rn;
334         rc = do_sync_request(cmd, sccb);
335         if (rc)
336                 goto out;
337         switch (sccb->header.response_code) {
338         case 0x0020:
339         case 0x0120:
340                 break;
341         default:
342                 pr_warning("assign storage failed (cmd=0x%08x, "
343                            "response=0x%04x, rn=0x%04x)\n", cmd,
344                            sccb->header.response_code, rn);
345                 rc = -EIO;
346                 break;
347         }
348 out:
349         free_page((unsigned long) sccb);
350         return rc;
351 }
352
353 static int sclp_assign_storage(u16 rn)
354 {
355         return do_assign_storage(0x000d0001, rn);
356 }
357
358 static int sclp_unassign_storage(u16 rn)
359 {
360         return do_assign_storage(0x000c0001, rn);
361 }
362
363 struct attach_storage_sccb {
364         struct sccb_header header;
365         u16 :16;
366         u16 assigned;
367         u32 :32;
368         u32 entries[0];
369 } __packed;
370
371 static int sclp_attach_storage(u8 id)
372 {
373         struct attach_storage_sccb *sccb;
374         int rc;
375         int i;
376
377         sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
378         if (!sccb)
379                 return -ENOMEM;
380         sccb->header.length = PAGE_SIZE;
381         rc = do_sync_request(0x00080001 | id << 8, sccb);
382         if (rc)
383                 goto out;
384         switch (sccb->header.response_code) {
385         case 0x0020:
386                 set_bit(id, sclp_storage_ids);
387                 for (i = 0; i < sccb->assigned; i++) {
388                         if (sccb->entries[i])
389                                 sclp_unassign_storage(sccb->entries[i] >> 16);
390                 }
391                 break;
392         default:
393                 rc = -EIO;
394                 break;
395         }
396 out:
397         free_page((unsigned long) sccb);
398         return rc;
399 }
400
401 static int sclp_mem_change_state(unsigned long start, unsigned long size,
402                                  int online)
403 {
404         struct memory_increment *incr;
405         unsigned long long istart;
406         int rc = 0;
407
408         list_for_each_entry(incr, &sclp_mem_list, list) {
409                 istart = rn2addr(incr->rn);
410                 if (start + size - 1 < istart)
411                         break;
412                 if (start > istart + rzm - 1)
413                         continue;
414                 if (online) {
415                         if (incr->usecount++)
416                                 continue;
417                         /*
418                          * Don't break the loop if one assign fails. Loop may
419                          * be walked again on CANCEL and we can't save
420                          * information if state changed before or not.
421                          * So continue and increase usecount for all increments.
422                          */
423                         rc |= sclp_assign_storage(incr->rn);
424                 } else {
425                         if (--incr->usecount)
426                                 continue;
427                         sclp_unassign_storage(incr->rn);
428                 }
429         }
430         return rc ? -EIO : 0;
431 }
432
433 static int sclp_mem_notifier(struct notifier_block *nb,
434                              unsigned long action, void *data)
435 {
436         unsigned long start, size;
437         struct memory_notify *arg;
438         unsigned char id;
439         int rc = 0;
440
441         arg = data;
442         start = arg->start_pfn << PAGE_SHIFT;
443         size = arg->nr_pages << PAGE_SHIFT;
444         mutex_lock(&sclp_mem_mutex);
445         for_each_clear_bit(id, sclp_storage_ids, sclp_max_storage_id + 1)
446                 sclp_attach_storage(id);
447         switch (action) {
448         case MEM_ONLINE:
449         case MEM_GOING_OFFLINE:
450         case MEM_CANCEL_OFFLINE:
451                 break;
452         case MEM_GOING_ONLINE:
453                 rc = sclp_mem_change_state(start, size, 1);
454                 break;
455         case MEM_CANCEL_ONLINE:
456                 sclp_mem_change_state(start, size, 0);
457                 break;
458         case MEM_OFFLINE:
459                 sclp_mem_change_state(start, size, 0);
460                 break;
461         default:
462                 rc = -EINVAL;
463                 break;
464         }
465         if (!rc)
466                 sclp_mem_state_changed = 1;
467         mutex_unlock(&sclp_mem_mutex);
468         return rc ? NOTIFY_BAD : NOTIFY_OK;
469 }
470
471 static struct notifier_block sclp_mem_nb = {
472         .notifier_call = sclp_mem_notifier,
473 };
474
475 static void __init add_memory_merged(u16 rn)
476 {
477         static u16 first_rn, num;
478         unsigned long long start, size;
479
480         if (rn && first_rn && (first_rn + num == rn)) {
481                 num++;
482                 return;
483         }
484         if (!first_rn)
485                 goto skip_add;
486         start = rn2addr(first_rn);
487         size = (unsigned long long ) num * rzm;
488         if (start >= VMEM_MAX_PHYS)
489                 goto skip_add;
490         if (start + size > VMEM_MAX_PHYS)
491                 size = VMEM_MAX_PHYS - start;
492         if (memory_end_set && (start >= memory_end))
493                 goto skip_add;
494         if (memory_end_set && (start + size > memory_end))
495                 size = memory_end - start;
496         add_memory(0, start, size);
497 skip_add:
498         first_rn = rn;
499         num = 1;
500 }
501
502 static void __init sclp_add_standby_memory(void)
503 {
504         struct memory_increment *incr;
505
506         list_for_each_entry(incr, &sclp_mem_list, list)
507                 if (incr->standby)
508                         add_memory_merged(incr->rn);
509         add_memory_merged(0);
510 }
511
512 static void __init insert_increment(u16 rn, int standby, int assigned)
513 {
514         struct memory_increment *incr, *new_incr;
515         struct list_head *prev;
516         u16 last_rn;
517
518         new_incr = kzalloc(sizeof(*new_incr), GFP_KERNEL);
519         if (!new_incr)
520                 return;
521         new_incr->rn = rn;
522         new_incr->standby = standby;
523         if (!standby)
524                 new_incr->usecount = 1;
525         last_rn = 0;
526         prev = &sclp_mem_list;
527         list_for_each_entry(incr, &sclp_mem_list, list) {
528                 if (assigned && incr->rn > rn)
529                         break;
530                 if (!assigned && incr->rn - last_rn > 1)
531                         break;
532                 last_rn = incr->rn;
533                 prev = &incr->list;
534         }
535         if (!assigned)
536                 new_incr->rn = last_rn + 1;
537         if (new_incr->rn > rnmax) {
538                 kfree(new_incr);
539                 return;
540         }
541         list_add(&new_incr->list, prev);
542 }
543
544 static int sclp_mem_freeze(struct device *dev)
545 {
546         if (!sclp_mem_state_changed)
547                 return 0;
548         pr_err("Memory hotplug state changed, suspend refused.\n");
549         return -EPERM;
550 }
551
552 struct read_storage_sccb {
553         struct sccb_header header;
554         u16 max_id;
555         u16 assigned;
556         u16 standby;
557         u16 :16;
558         u32 entries[0];
559 } __packed;
560
561 static const struct dev_pm_ops sclp_mem_pm_ops = {
562         .freeze         = sclp_mem_freeze,
563 };
564
565 static struct platform_driver sclp_mem_pdrv = {
566         .driver = {
567                 .name   = "sclp_mem",
568                 .pm     = &sclp_mem_pm_ops,
569         },
570 };
571
572 static int __init sclp_detect_standby_memory(void)
573 {
574         struct platform_device *sclp_pdev;
575         struct read_storage_sccb *sccb;
576         int i, id, assigned, rc;
577
578         if (!early_read_info_sccb_valid)
579                 return 0;
580         if ((sclp_facilities & 0xe00000000000ULL) != 0xe00000000000ULL)
581                 return 0;
582         rc = -ENOMEM;
583         sccb = (void *) __get_free_page(GFP_KERNEL | GFP_DMA);
584         if (!sccb)
585                 goto out;
586         assigned = 0;
587         for (id = 0; id <= sclp_max_storage_id; id++) {
588                 memset(sccb, 0, PAGE_SIZE);
589                 sccb->header.length = PAGE_SIZE;
590                 rc = do_sync_request(0x00040001 | id << 8, sccb);
591                 if (rc)
592                         goto out;
593                 switch (sccb->header.response_code) {
594                 case 0x0010:
595                         set_bit(id, sclp_storage_ids);
596                         for (i = 0; i < sccb->assigned; i++) {
597                                 if (!sccb->entries[i])
598                                         continue;
599                                 assigned++;
600                                 insert_increment(sccb->entries[i] >> 16, 0, 1);
601                         }
602                         break;
603                 case 0x0310:
604                         break;
605                 case 0x0410:
606                         for (i = 0; i < sccb->assigned; i++) {
607                                 if (!sccb->entries[i])
608                                         continue;
609                                 assigned++;
610                                 insert_increment(sccb->entries[i] >> 16, 1, 1);
611                         }
612                         break;
613                 default:
614                         rc = -EIO;
615                         break;
616                 }
617                 if (!rc)
618                         sclp_max_storage_id = sccb->max_id;
619         }
620         if (rc || list_empty(&sclp_mem_list))
621                 goto out;
622         for (i = 1; i <= rnmax - assigned; i++)
623                 insert_increment(0, 1, 0);
624         rc = register_memory_notifier(&sclp_mem_nb);
625         if (rc)
626                 goto out;
627         rc = platform_driver_register(&sclp_mem_pdrv);
628         if (rc)
629                 goto out;
630         sclp_pdev = platform_device_register_simple("sclp_mem", -1, NULL, 0);
631         rc = IS_ERR(sclp_pdev) ? PTR_ERR(sclp_pdev) : 0;
632         if (rc)
633                 goto out_driver;
634         sclp_add_standby_memory();
635         goto out;
636 out_driver:
637         platform_driver_unregister(&sclp_mem_pdrv);
638 out:
639         free_page((unsigned long) sccb);
640         return rc;
641 }
642 __initcall(sclp_detect_standby_memory);
643
644 #endif /* CONFIG_MEMORY_HOTPLUG */
645
646 /*
647  * Channel path configuration related functions.
648  */
649
650 #define SCLP_CMDW_CONFIGURE_CHPATH              0x000f0001
651 #define SCLP_CMDW_DECONFIGURE_CHPATH            0x000e0001
652 #define SCLP_CMDW_READ_CHPATH_INFORMATION       0x00030001
653
654 struct chp_cfg_sccb {
655         struct sccb_header header;
656         u8 ccm;
657         u8 reserved[6];
658         u8 cssid;
659 } __attribute__((packed));
660
661 static int do_chp_configure(sclp_cmdw_t cmd)
662 {
663         struct chp_cfg_sccb *sccb;
664         int rc;
665
666         if (!SCLP_HAS_CHP_RECONFIG)
667                 return -EOPNOTSUPP;
668         /* Prepare sccb. */
669         sccb = (struct chp_cfg_sccb *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
670         if (!sccb)
671                 return -ENOMEM;
672         sccb->header.length = sizeof(*sccb);
673         rc = do_sync_request(cmd, sccb);
674         if (rc)
675                 goto out;
676         switch (sccb->header.response_code) {
677         case 0x0020:
678         case 0x0120:
679         case 0x0440:
680         case 0x0450:
681                 break;
682         default:
683                 pr_warning("configure channel-path failed "
684                            "(cmd=0x%08x, response=0x%04x)\n", cmd,
685                            sccb->header.response_code);
686                 rc = -EIO;
687                 break;
688         }
689 out:
690         free_page((unsigned long) sccb);
691         return rc;
692 }
693
694 /**
695  * sclp_chp_configure - perform configure channel-path sclp command
696  * @chpid: channel-path ID
697  *
698  * Perform configure channel-path command sclp command for specified chpid.
699  * Return 0 after command successfully finished, non-zero otherwise.
700  */
701 int sclp_chp_configure(struct chp_id chpid)
702 {
703         return do_chp_configure(SCLP_CMDW_CONFIGURE_CHPATH | chpid.id << 8);
704 }
705
706 /**
707  * sclp_chp_deconfigure - perform deconfigure channel-path sclp command
708  * @chpid: channel-path ID
709  *
710  * Perform deconfigure channel-path command sclp command for specified chpid
711  * and wait for completion. On success return 0. Return non-zero otherwise.
712  */
713 int sclp_chp_deconfigure(struct chp_id chpid)
714 {
715         return do_chp_configure(SCLP_CMDW_DECONFIGURE_CHPATH | chpid.id << 8);
716 }
717
718 struct chp_info_sccb {
719         struct sccb_header header;
720         u8 recognized[SCLP_CHP_INFO_MASK_SIZE];
721         u8 standby[SCLP_CHP_INFO_MASK_SIZE];
722         u8 configured[SCLP_CHP_INFO_MASK_SIZE];
723         u8 ccm;
724         u8 reserved[6];
725         u8 cssid;
726 } __attribute__((packed));
727
728 /**
729  * sclp_chp_read_info - perform read channel-path information sclp command
730  * @info: resulting channel-path information data
731  *
732  * Perform read channel-path information sclp command and wait for completion.
733  * On success, store channel-path information in @info and return 0. Return
734  * non-zero otherwise.
735  */
736 int sclp_chp_read_info(struct sclp_chp_info *info)
737 {
738         struct chp_info_sccb *sccb;
739         int rc;
740
741         if (!SCLP_HAS_CHP_INFO)
742                 return -EOPNOTSUPP;
743         /* Prepare sccb. */
744         sccb = (struct chp_info_sccb *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
745         if (!sccb)
746                 return -ENOMEM;
747         sccb->header.length = sizeof(*sccb);
748         rc = do_sync_request(SCLP_CMDW_READ_CHPATH_INFORMATION, sccb);
749         if (rc)
750                 goto out;
751         if (sccb->header.response_code != 0x0010) {
752                 pr_warning("read channel-path info failed "
753                            "(response=0x%04x)\n", sccb->header.response_code);
754                 rc = -EIO;
755                 goto out;
756         }
757         memcpy(info->recognized, sccb->recognized, SCLP_CHP_INFO_MASK_SIZE);
758         memcpy(info->standby, sccb->standby, SCLP_CHP_INFO_MASK_SIZE);
759         memcpy(info->configured, sccb->configured, SCLP_CHP_INFO_MASK_SIZE);
760 out:
761         free_page((unsigned long) sccb);
762         return rc;
763 }