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Merge tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck...
[~andy/linux] / 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         unsigned long long start, address;
356         int rc;
357
358         rc = do_assign_storage(0x000d0001, rn);
359         if (rc)
360                 goto out;
361         start = address = rn2addr(rn);
362         for (; address < start + rzm; address += PAGE_SIZE)
363                 page_set_storage_key(address, PAGE_DEFAULT_KEY, 0);
364 out:
365         return rc;
366 }
367
368 static int sclp_unassign_storage(u16 rn)
369 {
370         return do_assign_storage(0x000c0001, rn);
371 }
372
373 struct attach_storage_sccb {
374         struct sccb_header header;
375         u16 :16;
376         u16 assigned;
377         u32 :32;
378         u32 entries[0];
379 } __packed;
380
381 static int sclp_attach_storage(u8 id)
382 {
383         struct attach_storage_sccb *sccb;
384         int rc;
385         int i;
386
387         sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
388         if (!sccb)
389                 return -ENOMEM;
390         sccb->header.length = PAGE_SIZE;
391         rc = do_sync_request(0x00080001 | id << 8, sccb);
392         if (rc)
393                 goto out;
394         switch (sccb->header.response_code) {
395         case 0x0020:
396                 set_bit(id, sclp_storage_ids);
397                 for (i = 0; i < sccb->assigned; i++) {
398                         if (sccb->entries[i])
399                                 sclp_unassign_storage(sccb->entries[i] >> 16);
400                 }
401                 break;
402         default:
403                 rc = -EIO;
404                 break;
405         }
406 out:
407         free_page((unsigned long) sccb);
408         return rc;
409 }
410
411 static int sclp_mem_change_state(unsigned long start, unsigned long size,
412                                  int online)
413 {
414         struct memory_increment *incr;
415         unsigned long long istart;
416         int rc = 0;
417
418         list_for_each_entry(incr, &sclp_mem_list, list) {
419                 istart = rn2addr(incr->rn);
420                 if (start + size - 1 < istart)
421                         break;
422                 if (start > istart + rzm - 1)
423                         continue;
424                 if (online) {
425                         if (incr->usecount++)
426                                 continue;
427                         /*
428                          * Don't break the loop if one assign fails. Loop may
429                          * be walked again on CANCEL and we can't save
430                          * information if state changed before or not.
431                          * So continue and increase usecount for all increments.
432                          */
433                         rc |= sclp_assign_storage(incr->rn);
434                 } else {
435                         if (--incr->usecount)
436                                 continue;
437                         sclp_unassign_storage(incr->rn);
438                 }
439         }
440         return rc ? -EIO : 0;
441 }
442
443 static int sclp_mem_notifier(struct notifier_block *nb,
444                              unsigned long action, void *data)
445 {
446         unsigned long start, size;
447         struct memory_notify *arg;
448         unsigned char id;
449         int rc = 0;
450
451         arg = data;
452         start = arg->start_pfn << PAGE_SHIFT;
453         size = arg->nr_pages << PAGE_SHIFT;
454         mutex_lock(&sclp_mem_mutex);
455         for_each_clear_bit(id, sclp_storage_ids, sclp_max_storage_id + 1)
456                 sclp_attach_storage(id);
457         switch (action) {
458         case MEM_ONLINE:
459         case MEM_GOING_OFFLINE:
460         case MEM_CANCEL_OFFLINE:
461                 break;
462         case MEM_GOING_ONLINE:
463                 rc = sclp_mem_change_state(start, size, 1);
464                 break;
465         case MEM_CANCEL_ONLINE:
466                 sclp_mem_change_state(start, size, 0);
467                 break;
468         case MEM_OFFLINE:
469                 sclp_mem_change_state(start, size, 0);
470                 break;
471         default:
472                 rc = -EINVAL;
473                 break;
474         }
475         if (!rc)
476                 sclp_mem_state_changed = 1;
477         mutex_unlock(&sclp_mem_mutex);
478         return rc ? NOTIFY_BAD : NOTIFY_OK;
479 }
480
481 static struct notifier_block sclp_mem_nb = {
482         .notifier_call = sclp_mem_notifier,
483 };
484
485 static void __init add_memory_merged(u16 rn)
486 {
487         static u16 first_rn, num;
488         unsigned long long start, size;
489
490         if (rn && first_rn && (first_rn + num == rn)) {
491                 num++;
492                 return;
493         }
494         if (!first_rn)
495                 goto skip_add;
496         start = rn2addr(first_rn);
497         size = (unsigned long long ) num * rzm;
498         if (start >= VMEM_MAX_PHYS)
499                 goto skip_add;
500         if (start + size > VMEM_MAX_PHYS)
501                 size = VMEM_MAX_PHYS - start;
502         if (memory_end_set && (start >= memory_end))
503                 goto skip_add;
504         if (memory_end_set && (start + size > memory_end))
505                 size = memory_end - start;
506         add_memory(0, start, size);
507 skip_add:
508         first_rn = rn;
509         num = 1;
510 }
511
512 static void __init sclp_add_standby_memory(void)
513 {
514         struct memory_increment *incr;
515
516         list_for_each_entry(incr, &sclp_mem_list, list)
517                 if (incr->standby)
518                         add_memory_merged(incr->rn);
519         add_memory_merged(0);
520 }
521
522 static void __init insert_increment(u16 rn, int standby, int assigned)
523 {
524         struct memory_increment *incr, *new_incr;
525         struct list_head *prev;
526         u16 last_rn;
527
528         new_incr = kzalloc(sizeof(*new_incr), GFP_KERNEL);
529         if (!new_incr)
530                 return;
531         new_incr->rn = rn;
532         new_incr->standby = standby;
533         if (!standby)
534                 new_incr->usecount = 1;
535         last_rn = 0;
536         prev = &sclp_mem_list;
537         list_for_each_entry(incr, &sclp_mem_list, list) {
538                 if (assigned && incr->rn > rn)
539                         break;
540                 if (!assigned && incr->rn - last_rn > 1)
541                         break;
542                 last_rn = incr->rn;
543                 prev = &incr->list;
544         }
545         if (!assigned)
546                 new_incr->rn = last_rn + 1;
547         if (new_incr->rn > rnmax) {
548                 kfree(new_incr);
549                 return;
550         }
551         list_add(&new_incr->list, prev);
552 }
553
554 static int sclp_mem_freeze(struct device *dev)
555 {
556         if (!sclp_mem_state_changed)
557                 return 0;
558         pr_err("Memory hotplug state changed, suspend refused.\n");
559         return -EPERM;
560 }
561
562 struct read_storage_sccb {
563         struct sccb_header header;
564         u16 max_id;
565         u16 assigned;
566         u16 standby;
567         u16 :16;
568         u32 entries[0];
569 } __packed;
570
571 static const struct dev_pm_ops sclp_mem_pm_ops = {
572         .freeze         = sclp_mem_freeze,
573 };
574
575 static struct platform_driver sclp_mem_pdrv = {
576         .driver = {
577                 .name   = "sclp_mem",
578                 .pm     = &sclp_mem_pm_ops,
579         },
580 };
581
582 static int __init sclp_detect_standby_memory(void)
583 {
584         struct platform_device *sclp_pdev;
585         struct read_storage_sccb *sccb;
586         int i, id, assigned, rc;
587
588         if (!early_read_info_sccb_valid)
589                 return 0;
590         if ((sclp_facilities & 0xe00000000000ULL) != 0xe00000000000ULL)
591                 return 0;
592         rc = -ENOMEM;
593         sccb = (void *) __get_free_page(GFP_KERNEL | GFP_DMA);
594         if (!sccb)
595                 goto out;
596         assigned = 0;
597         for (id = 0; id <= sclp_max_storage_id; id++) {
598                 memset(sccb, 0, PAGE_SIZE);
599                 sccb->header.length = PAGE_SIZE;
600                 rc = do_sync_request(0x00040001 | id << 8, sccb);
601                 if (rc)
602                         goto out;
603                 switch (sccb->header.response_code) {
604                 case 0x0010:
605                         set_bit(id, sclp_storage_ids);
606                         for (i = 0; i < sccb->assigned; i++) {
607                                 if (!sccb->entries[i])
608                                         continue;
609                                 assigned++;
610                                 insert_increment(sccb->entries[i] >> 16, 0, 1);
611                         }
612                         break;
613                 case 0x0310:
614                         break;
615                 case 0x0410:
616                         for (i = 0; i < sccb->assigned; i++) {
617                                 if (!sccb->entries[i])
618                                         continue;
619                                 assigned++;
620                                 insert_increment(sccb->entries[i] >> 16, 1, 1);
621                         }
622                         break;
623                 default:
624                         rc = -EIO;
625                         break;
626                 }
627                 if (!rc)
628                         sclp_max_storage_id = sccb->max_id;
629         }
630         if (rc || list_empty(&sclp_mem_list))
631                 goto out;
632         for (i = 1; i <= rnmax - assigned; i++)
633                 insert_increment(0, 1, 0);
634         rc = register_memory_notifier(&sclp_mem_nb);
635         if (rc)
636                 goto out;
637         rc = platform_driver_register(&sclp_mem_pdrv);
638         if (rc)
639                 goto out;
640         sclp_pdev = platform_device_register_simple("sclp_mem", -1, NULL, 0);
641         rc = IS_ERR(sclp_pdev) ? PTR_ERR(sclp_pdev) : 0;
642         if (rc)
643                 goto out_driver;
644         sclp_add_standby_memory();
645         goto out;
646 out_driver:
647         platform_driver_unregister(&sclp_mem_pdrv);
648 out:
649         free_page((unsigned long) sccb);
650         return rc;
651 }
652 __initcall(sclp_detect_standby_memory);
653
654 #endif /* CONFIG_MEMORY_HOTPLUG */
655
656 /*
657  * Channel path configuration related functions.
658  */
659
660 #define SCLP_CMDW_CONFIGURE_CHPATH              0x000f0001
661 #define SCLP_CMDW_DECONFIGURE_CHPATH            0x000e0001
662 #define SCLP_CMDW_READ_CHPATH_INFORMATION       0x00030001
663
664 struct chp_cfg_sccb {
665         struct sccb_header header;
666         u8 ccm;
667         u8 reserved[6];
668         u8 cssid;
669 } __attribute__((packed));
670
671 static int do_chp_configure(sclp_cmdw_t cmd)
672 {
673         struct chp_cfg_sccb *sccb;
674         int rc;
675
676         if (!SCLP_HAS_CHP_RECONFIG)
677                 return -EOPNOTSUPP;
678         /* Prepare sccb. */
679         sccb = (struct chp_cfg_sccb *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
680         if (!sccb)
681                 return -ENOMEM;
682         sccb->header.length = sizeof(*sccb);
683         rc = do_sync_request(cmd, sccb);
684         if (rc)
685                 goto out;
686         switch (sccb->header.response_code) {
687         case 0x0020:
688         case 0x0120:
689         case 0x0440:
690         case 0x0450:
691                 break;
692         default:
693                 pr_warning("configure channel-path failed "
694                            "(cmd=0x%08x, response=0x%04x)\n", cmd,
695                            sccb->header.response_code);
696                 rc = -EIO;
697                 break;
698         }
699 out:
700         free_page((unsigned long) sccb);
701         return rc;
702 }
703
704 /**
705  * sclp_chp_configure - perform configure channel-path sclp command
706  * @chpid: channel-path ID
707  *
708  * Perform configure channel-path command sclp command for specified chpid.
709  * Return 0 after command successfully finished, non-zero otherwise.
710  */
711 int sclp_chp_configure(struct chp_id chpid)
712 {
713         return do_chp_configure(SCLP_CMDW_CONFIGURE_CHPATH | chpid.id << 8);
714 }
715
716 /**
717  * sclp_chp_deconfigure - perform deconfigure channel-path sclp command
718  * @chpid: channel-path ID
719  *
720  * Perform deconfigure channel-path command sclp command for specified chpid
721  * and wait for completion. On success return 0. Return non-zero otherwise.
722  */
723 int sclp_chp_deconfigure(struct chp_id chpid)
724 {
725         return do_chp_configure(SCLP_CMDW_DECONFIGURE_CHPATH | chpid.id << 8);
726 }
727
728 struct chp_info_sccb {
729         struct sccb_header header;
730         u8 recognized[SCLP_CHP_INFO_MASK_SIZE];
731         u8 standby[SCLP_CHP_INFO_MASK_SIZE];
732         u8 configured[SCLP_CHP_INFO_MASK_SIZE];
733         u8 ccm;
734         u8 reserved[6];
735         u8 cssid;
736 } __attribute__((packed));
737
738 /**
739  * sclp_chp_read_info - perform read channel-path information sclp command
740  * @info: resulting channel-path information data
741  *
742  * Perform read channel-path information sclp command and wait for completion.
743  * On success, store channel-path information in @info and return 0. Return
744  * non-zero otherwise.
745  */
746 int sclp_chp_read_info(struct sclp_chp_info *info)
747 {
748         struct chp_info_sccb *sccb;
749         int rc;
750
751         if (!SCLP_HAS_CHP_INFO)
752                 return -EOPNOTSUPP;
753         /* Prepare sccb. */
754         sccb = (struct chp_info_sccb *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
755         if (!sccb)
756                 return -ENOMEM;
757         sccb->header.length = sizeof(*sccb);
758         rc = do_sync_request(SCLP_CMDW_READ_CHPATH_INFORMATION, sccb);
759         if (rc)
760                 goto out;
761         if (sccb->header.response_code != 0x0010) {
762                 pr_warning("read channel-path info failed "
763                            "(response=0x%04x)\n", sccb->header.response_code);
764                 rc = -EIO;
765                 goto out;
766         }
767         memcpy(info->recognized, sccb->recognized, SCLP_CHP_INFO_MASK_SIZE);
768         memcpy(info->standby, sccb->standby, SCLP_CHP_INFO_MASK_SIZE);
769         memcpy(info->configured, sccb->configured, SCLP_CHP_INFO_MASK_SIZE);
770 out:
771         free_page((unsigned long) sccb);
772         return rc;
773 }