PCI hotplug: create symlink to hotplug driver module
[linux-2.6.git] / drivers / pci / hotplug / sgi_hotplug.c
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (C) 2005-2006 Silicon Graphics, Inc. All rights reserved.
7  *
8  * This work was based on the 2.4/2.6 kernel development by Dick Reigner.
9  * Work to add BIOS PROM support was completed by Mike Habeck.
10  */
11
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/pci.h>
16 #include <linux/pci_hotplug.h>
17 #include <linux/proc_fs.h>
18 #include <linux/types.h>
19 #include <linux/mutex.h>
20
21 #include <asm/sn/addrs.h>
22 #include <asm/sn/geo.h>
23 #include <asm/sn/l1.h>
24 #include <asm/sn/module.h>
25 #include <asm/sn/pcibr_provider.h>
26 #include <asm/sn/pcibus_provider_defs.h>
27 #include <asm/sn/pcidev.h>
28 #include <asm/sn/sn_feature_sets.h>
29 #include <asm/sn/sn_sal.h>
30 #include <asm/sn/types.h>
31 #include <linux/acpi.h>
32 #include <asm/sn/acpi.h>
33
34 #include "../pci.h"
35
36 MODULE_LICENSE("GPL");
37 MODULE_AUTHOR("SGI (prarit@sgi.com, dickie@sgi.com, habeck@sgi.com)");
38 MODULE_DESCRIPTION("SGI Altix Hot Plug PCI Controller Driver");
39
40
41 /* SAL call error codes. Keep in sync with prom header io/include/pcibr.h */
42 #define PCI_SLOT_ALREADY_UP             2       /* slot already up */
43 #define PCI_SLOT_ALREADY_DOWN           3       /* slot already down */
44 #define PCI_L1_ERR                      7       /* L1 console command error */
45 #define PCI_EMPTY_33MHZ                 15      /* empty 33 MHz bus */
46
47
48 #define PCIIO_ASIC_TYPE_TIOCA           4
49 #define PCI_L1_QSIZE                    128     /* our L1 message buffer size */
50 #define SN_MAX_HP_SLOTS                 32      /* max hotplug slots */
51 #define SN_SLOT_NAME_SIZE               33      /* size of name string */
52
53 /* internal list head */
54 static struct list_head sn_hp_list;
55
56 /* hotplug_slot struct's private pointer */
57 struct slot {
58         int device_num;
59         struct pci_bus *pci_bus;
60         /* this struct for glue internal only */
61         struct hotplug_slot *hotplug_slot;
62         struct list_head hp_list;
63         char physical_path[SN_SLOT_NAME_SIZE];
64 };
65
66 struct pcibr_slot_enable_resp {
67         int resp_sub_errno;
68         char resp_l1_msg[PCI_L1_QSIZE + 1];
69 };
70
71 struct pcibr_slot_disable_resp {
72         int resp_sub_errno;
73         char resp_l1_msg[PCI_L1_QSIZE + 1];
74 };
75
76 enum sn_pci_req_e {
77         PCI_REQ_SLOT_ELIGIBLE,
78         PCI_REQ_SLOT_DISABLE
79 };
80
81 static int enable_slot(struct hotplug_slot *slot);
82 static int disable_slot(struct hotplug_slot *slot);
83 static inline int get_power_status(struct hotplug_slot *slot, u8 *value);
84
85 static struct hotplug_slot_ops sn_hotplug_slot_ops = {
86         .owner                  = THIS_MODULE,
87         .enable_slot            = enable_slot,
88         .disable_slot           = disable_slot,
89         .get_power_status       = get_power_status,
90 };
91
92 static DEFINE_MUTEX(sn_hotplug_mutex);
93
94 static ssize_t path_show (struct hotplug_slot *bss_hotplug_slot,
95                           char *buf)
96 {
97         int retval = -ENOENT;
98         struct slot *slot = bss_hotplug_slot->private;
99
100         if (!slot)
101                 return retval;
102
103         retval = sprintf (buf, "%s\n", slot->physical_path);
104         return retval;
105 }
106
107 static struct hotplug_slot_attribute sn_slot_path_attr = __ATTR_RO(path);
108
109 static int sn_pci_slot_valid(struct pci_bus *pci_bus, int device)
110 {
111         struct pcibus_info *pcibus_info;
112         u16 busnum, segment, ioboard_type;
113
114         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(pci_bus);
115
116         /* Check to see if this is a valid slot on 'pci_bus' */
117         if (!(pcibus_info->pbi_valid_devices & (1 << device)))
118                 return -EPERM;
119
120         ioboard_type = sn_ioboard_to_pci_bus(pci_bus);
121         busnum = pcibus_info->pbi_buscommon.bs_persist_busnum;
122         segment = pci_domain_nr(pci_bus) & 0xf;
123
124         /* Do not allow hotplug operations on base I/O cards */
125         if ((ioboard_type == L1_BRICKTYPE_IX ||
126              ioboard_type == L1_BRICKTYPE_IA) &&
127             (segment == 1 && busnum == 0 && device != 1))
128                 return -EPERM;
129
130         return 1;
131 }
132
133 static int sn_pci_bus_valid(struct pci_bus *pci_bus)
134 {
135         struct pcibus_info *pcibus_info;
136         u32 asic_type;
137         u16 ioboard_type;
138
139         /* Don't register slots hanging off the TIOCA bus */
140         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(pci_bus);
141         asic_type = pcibus_info->pbi_buscommon.bs_asic_type;
142         if (asic_type == PCIIO_ASIC_TYPE_TIOCA)
143                 return -EPERM;
144
145         /* Only register slots in I/O Bricks that support hotplug */
146         ioboard_type = sn_ioboard_to_pci_bus(pci_bus);
147         switch (ioboard_type) {
148                 case L1_BRICKTYPE_IX:
149                 case L1_BRICKTYPE_PX:
150                 case L1_BRICKTYPE_IA:
151                 case L1_BRICKTYPE_PA:
152                 case L1_BOARDTYPE_PCIX3SLOT:
153                         return 1;
154                         break;
155                 default:
156                         return -EPERM;
157                         break;
158         }
159
160         return -EIO;
161 }
162
163 static int sn_hp_slot_private_alloc(struct hotplug_slot *bss_hotplug_slot,
164                                     struct pci_bus *pci_bus, int device,
165                                     char *name)
166 {
167         struct pcibus_info *pcibus_info;
168         struct slot *slot;
169
170         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(pci_bus);
171
172         slot = kzalloc(sizeof(*slot), GFP_KERNEL);
173         if (!slot)
174                 return -ENOMEM;
175         bss_hotplug_slot->private = slot;
176
177         slot->device_num = device;
178         slot->pci_bus = pci_bus;
179         sprintf(name, "%04x:%02x:%02x",
180                 pci_domain_nr(pci_bus),
181                 ((u16)pcibus_info->pbi_buscommon.bs_persist_busnum),
182                 device + 1);
183
184         sn_generate_path(pci_bus, slot->physical_path);
185
186         slot->hotplug_slot = bss_hotplug_slot;
187         list_add(&slot->hp_list, &sn_hp_list);
188
189         return 0;
190 }
191
192 static struct hotplug_slot * sn_hp_destroy(void)
193 {
194         struct slot *slot;
195         struct pci_slot *pci_slot;
196         struct hotplug_slot *bss_hotplug_slot = NULL;
197
198         list_for_each_entry(slot, &sn_hp_list, hp_list) {
199                 bss_hotplug_slot = slot->hotplug_slot;
200                 pci_slot = bss_hotplug_slot->pci_slot;
201                 list_del(&((struct slot *)bss_hotplug_slot->private)->
202                          hp_list);
203                 sysfs_remove_file(&pci_slot->kobj,
204                                   &sn_slot_path_attr.attr);
205                 break;
206         }
207         return bss_hotplug_slot;
208 }
209
210 static void sn_bus_free_data(struct pci_dev *dev)
211 {
212         struct pci_bus *subordinate_bus;
213         struct pci_dev *child;
214
215         /* Recursively clean up sn_irq_info structs */
216         if (dev->subordinate) {
217                 subordinate_bus = dev->subordinate;
218                 list_for_each_entry(child, &subordinate_bus->devices, bus_list)
219                         sn_bus_free_data(child);
220         }
221         /*
222          * Some drivers may use dma accesses during the
223          * driver remove function. We release the sysdata
224          * areas after the driver remove functions have
225          * been called.
226          */
227         sn_bus_store_sysdata(dev);
228         sn_pci_unfixup_slot(dev);
229 }
230
231 static int sn_slot_enable(struct hotplug_slot *bss_hotplug_slot,
232                           int device_num, char **ssdt)
233 {
234         struct slot *slot = bss_hotplug_slot->private;
235         struct pcibus_info *pcibus_info;
236         struct pcibr_slot_enable_resp resp;
237         int rc;
238
239         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
240
241         /*
242          * Power-on and initialize the slot in the SN
243          * PCI infrastructure.
244          */
245         rc = sal_pcibr_slot_enable(pcibus_info, device_num, &resp, ssdt);
246
247
248         if (rc == PCI_SLOT_ALREADY_UP) {
249                 dev_dbg(&slot->pci_bus->self->dev, "is already active\n");
250                 return 1; /* return 1 to user */
251         }
252
253         if (rc == PCI_L1_ERR) {
254                 dev_dbg(&slot->pci_bus->self->dev,
255                         "L1 failure %d with message: %s",
256                         resp.resp_sub_errno, resp.resp_l1_msg);
257                 return -EPERM;
258         }
259
260         if (rc) {
261                 dev_dbg(&slot->pci_bus->self->dev,
262                         "insert failed with error %d sub-error %d\n",
263                         rc, resp.resp_sub_errno);
264                 return -EIO;
265         }
266
267         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
268         pcibus_info->pbi_enabled_devices |= (1 << device_num);
269
270         return 0;
271 }
272
273 static int sn_slot_disable(struct hotplug_slot *bss_hotplug_slot,
274                            int device_num, int action)
275 {
276         struct slot *slot = bss_hotplug_slot->private;
277         struct pcibus_info *pcibus_info;
278         struct pcibr_slot_disable_resp resp;
279         int rc;
280
281         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
282
283         rc = sal_pcibr_slot_disable(pcibus_info, device_num, action, &resp);
284
285         if ((action == PCI_REQ_SLOT_ELIGIBLE) &&
286             (rc == PCI_SLOT_ALREADY_DOWN)) {
287                 dev_dbg(&slot->pci_bus->self->dev, "Slot %s already inactive\n", slot->physical_path);
288                 return 1; /* return 1 to user */
289         }
290
291         if ((action == PCI_REQ_SLOT_ELIGIBLE) && (rc == PCI_EMPTY_33MHZ)) {
292                 dev_dbg(&slot->pci_bus->self->dev,
293                         "Cannot remove last 33MHz card\n");
294                 return -EPERM;
295         }
296
297         if ((action == PCI_REQ_SLOT_ELIGIBLE) && (rc == PCI_L1_ERR)) {
298                 dev_dbg(&slot->pci_bus->self->dev,
299                         "L1 failure %d with message \n%s\n",
300                         resp.resp_sub_errno, resp.resp_l1_msg);
301                 return -EPERM;
302         }
303
304         if ((action == PCI_REQ_SLOT_ELIGIBLE) && rc) {
305                 dev_dbg(&slot->pci_bus->self->dev,
306                         "remove failed with error %d sub-error %d\n",
307                         rc, resp.resp_sub_errno);
308                 return -EIO;
309         }
310
311         if ((action == PCI_REQ_SLOT_ELIGIBLE) && !rc)
312                 return 0;
313
314         if ((action == PCI_REQ_SLOT_DISABLE) && !rc) {
315                 pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
316                 pcibus_info->pbi_enabled_devices &= ~(1 << device_num);
317                 dev_dbg(&slot->pci_bus->self->dev, "remove successful\n");
318                 return 0;
319         }
320
321         if ((action == PCI_REQ_SLOT_DISABLE) && rc) {
322                 dev_dbg(&slot->pci_bus->self->dev,"remove failed rc = %d\n", rc);
323         }
324
325         return rc;
326 }
327
328 /*
329  * Power up and configure the slot via a SAL call to PROM.
330  * Scan slot (and any children), do any platform specific fixup,
331  * and find device driver.
332  */
333 static int enable_slot(struct hotplug_slot *bss_hotplug_slot)
334 {
335         struct slot *slot = bss_hotplug_slot->private;
336         struct pci_bus *new_bus = NULL;
337         struct pci_dev *dev;
338         int func, num_funcs;
339         int new_ppb = 0;
340         int rc;
341         char *ssdt = NULL;
342         void pcibios_fixup_device_resources(struct pci_dev *);
343
344         /* Serialize the Linux PCI infrastructure */
345         mutex_lock(&sn_hotplug_mutex);
346
347         /*
348          * Power-on and initialize the slot in the SN
349          * PCI infrastructure. Also, retrieve the ACPI SSDT
350          * table for the slot (if ACPI capable PROM).
351          */
352         rc = sn_slot_enable(bss_hotplug_slot, slot->device_num, &ssdt);
353         if (rc) {
354                 mutex_unlock(&sn_hotplug_mutex);
355                 return rc;
356         }
357
358         if (ssdt)
359                 ssdt = __va(ssdt);
360         /* Add the new SSDT for the slot to the ACPI namespace */
361         if (SN_ACPI_BASE_SUPPORT() && ssdt) {
362                 acpi_status ret;
363
364                 ret = acpi_load_table((struct acpi_table_header *)ssdt);
365                 if (ACPI_FAILURE(ret)) {
366                         printk(KERN_ERR "%s: acpi_load_table failed (0x%x)\n",
367                                __func__, ret);
368                         /* try to continue on */
369                 }
370         }
371
372         num_funcs = pci_scan_slot(slot->pci_bus,
373                                   PCI_DEVFN(slot->device_num + 1, 0));
374         if (!num_funcs) {
375                 dev_dbg(&slot->pci_bus->self->dev, "no device in slot\n");
376                 mutex_unlock(&sn_hotplug_mutex);
377                 return -ENODEV;
378         }
379
380         /*
381          * Map SN resources for all functions on the card
382          * to the Linux PCI interface and tell the drivers
383          * about them.
384          */
385         for (func = 0; func < num_funcs;  func++) {
386                 dev = pci_get_slot(slot->pci_bus,
387                                    PCI_DEVFN(slot->device_num + 1,
388                                              PCI_FUNC(func)));
389                 if (dev) {
390                         /* Need to do slot fixup on PPB before fixup of children
391                          * (PPB's pcidev_info needs to be in pcidev_info list
392                          * before child's SN_PCIDEV_INFO() call to setup
393                          * pdi_host_pcidev_info).
394                          */
395                         pcibios_fixup_device_resources(dev);
396                         if (SN_ACPI_BASE_SUPPORT())
397                                 sn_acpi_slot_fixup(dev);
398                         else
399                                 sn_io_slot_fixup(dev);
400                         if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
401                                 unsigned char sec_bus;
402                                 pci_read_config_byte(dev, PCI_SECONDARY_BUS,
403                                                      &sec_bus);
404                                 new_bus = pci_add_new_bus(dev->bus, dev,
405                                                           sec_bus);
406                                 pci_scan_child_bus(new_bus);
407                                 new_ppb = 1;
408                         }
409                         pci_dev_put(dev);
410                 }
411         }
412
413         /*
414          * Add the slot's devices to the ACPI infrastructure */
415         if (SN_ACPI_BASE_SUPPORT() && ssdt) {
416                 unsigned long long adr;
417                 struct acpi_device *pdevice;
418                 struct acpi_device *device;
419                 acpi_handle phandle;
420                 acpi_handle chandle = NULL;
421                 acpi_handle rethandle;
422                 acpi_status ret;
423
424                 phandle = PCI_CONTROLLER(slot->pci_bus)->acpi_handle;
425
426                 if (acpi_bus_get_device(phandle, &pdevice)) {
427                         dev_dbg(&slot->pci_bus->self->dev,
428                                 "no parent device, assuming NULL\n");
429                         pdevice = NULL;
430                 }
431
432                 /*
433                  * Walk the rootbus node's immediate children looking for
434                  * the slot's device node(s). There can be more than
435                  * one for multifunction devices.
436                  */
437                 for (;;) {
438                         rethandle = NULL;
439                         ret = acpi_get_next_object(ACPI_TYPE_DEVICE,
440                                                    phandle, chandle,
441                                                    &rethandle);
442
443                         if (ret == AE_NOT_FOUND || rethandle == NULL)
444                                 break;
445
446                         chandle = rethandle;
447
448                         ret = acpi_evaluate_integer(chandle, METHOD_NAME__ADR,
449                                                     NULL, &adr);
450
451                         if (ACPI_SUCCESS(ret) &&
452                             (adr>>16) == (slot->device_num + 1)) {
453
454                                 ret = acpi_bus_add(&device, pdevice, chandle,
455                                                    ACPI_BUS_TYPE_DEVICE);
456                                 if (ACPI_FAILURE(ret)) {
457                                         printk(KERN_ERR "%s: acpi_bus_add "
458                                                "failed (0x%x) for slot %d "
459                                                "func %d\n", __func__,
460                                                ret, (int)(adr>>16),
461                                                (int)(adr&0xffff));
462                                         /* try to continue on */
463                                 } else {
464                                         acpi_bus_start(device);
465                                 }
466                         }
467                 }
468         }
469
470         /* Call the driver for the new device */
471         pci_bus_add_devices(slot->pci_bus);
472         /* Call the drivers for the new devices subordinate to PPB */
473         if (new_ppb)
474                 pci_bus_add_devices(new_bus);
475
476         mutex_unlock(&sn_hotplug_mutex);
477
478         if (rc == 0)
479                 dev_dbg(&slot->pci_bus->self->dev,
480                         "insert operation successful\n");
481         else
482                 dev_dbg(&slot->pci_bus->self->dev,
483                         "insert operation failed rc = %d\n", rc);
484
485         return rc;
486 }
487
488 static int disable_slot(struct hotplug_slot *bss_hotplug_slot)
489 {
490         struct slot *slot = bss_hotplug_slot->private;
491         struct pci_dev *dev;
492         int func;
493         int rc;
494         acpi_owner_id ssdt_id = 0;
495
496         /* Acquire update access to the bus */
497         mutex_lock(&sn_hotplug_mutex);
498
499         /* is it okay to bring this slot down? */
500         rc = sn_slot_disable(bss_hotplug_slot, slot->device_num,
501                              PCI_REQ_SLOT_ELIGIBLE);
502         if (rc)
503                 goto leaving;
504
505         /* free the ACPI resources for the slot */
506         if (SN_ACPI_BASE_SUPPORT() &&
507             PCI_CONTROLLER(slot->pci_bus)->acpi_handle) {
508                 unsigned long long adr;
509                 struct acpi_device *device;
510                 acpi_handle phandle;
511                 acpi_handle chandle = NULL;
512                 acpi_handle rethandle;
513                 acpi_status ret;
514
515                 /* Get the rootbus node pointer */
516                 phandle = PCI_CONTROLLER(slot->pci_bus)->acpi_handle;
517
518                 /*
519                  * Walk the rootbus node's immediate children looking for
520                  * the slot's device node(s). There can be more than
521                  * one for multifunction devices.
522                  */
523                 for (;;) {
524                         rethandle = NULL;
525                         ret = acpi_get_next_object(ACPI_TYPE_DEVICE,
526                                                    phandle, chandle,
527                                                    &rethandle);
528
529                         if (ret == AE_NOT_FOUND || rethandle == NULL)
530                                 break;
531
532                         chandle = rethandle;
533
534                         ret = acpi_evaluate_integer(chandle,
535                                                     METHOD_NAME__ADR,
536                                                     NULL, &adr);
537                         if (ACPI_SUCCESS(ret) &&
538                             (adr>>16) == (slot->device_num + 1)) {
539                                 /* retain the owner id */
540                                 acpi_get_id(chandle, &ssdt_id);
541
542                                 ret = acpi_bus_get_device(chandle,
543                                                           &device);
544                                 if (ACPI_SUCCESS(ret))
545                                         acpi_bus_trim(device, 1);
546                         }
547                 }
548
549         }
550
551         /* Free the SN resources assigned to the Linux device.*/
552         for (func = 0; func < 8;  func++) {
553                 dev = pci_get_slot(slot->pci_bus,
554                                    PCI_DEVFN(slot->device_num + 1,
555                                              PCI_FUNC(func)));
556                 if (dev) {
557                         sn_bus_free_data(dev);
558                         pci_remove_bus_device(dev);
559                         pci_dev_put(dev);
560                 }
561         }
562
563         /* Remove the SSDT for the slot from the ACPI namespace */
564         if (SN_ACPI_BASE_SUPPORT() && ssdt_id) {
565                 acpi_status ret;
566                 ret = acpi_unload_table_id(ssdt_id);
567                 if (ACPI_FAILURE(ret)) {
568                         printk(KERN_ERR "%s: acpi_unload_table_id "
569                                "failed (0x%x) for id %d\n",
570                                __func__, ret, ssdt_id);
571                         /* try to continue on */
572                 }
573         }
574
575         /* free the collected sysdata pointers */
576         sn_bus_free_sysdata();
577
578         /* Deactivate slot */
579         rc = sn_slot_disable(bss_hotplug_slot, slot->device_num,
580                              PCI_REQ_SLOT_DISABLE);
581  leaving:
582         /* Release the bus lock */
583         mutex_unlock(&sn_hotplug_mutex);
584
585         return rc;
586 }
587
588 static inline int get_power_status(struct hotplug_slot *bss_hotplug_slot,
589                                    u8 *value)
590 {
591         struct slot *slot = bss_hotplug_slot->private;
592         struct pcibus_info *pcibus_info;
593         u32 power;
594
595         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
596         mutex_lock(&sn_hotplug_mutex);
597         power = pcibus_info->pbi_enabled_devices & (1 << slot->device_num);
598         *value = power ? 1 : 0;
599         mutex_unlock(&sn_hotplug_mutex);
600         return 0;
601 }
602
603 static void sn_release_slot(struct hotplug_slot *bss_hotplug_slot)
604 {
605         kfree(bss_hotplug_slot->info);
606         kfree(bss_hotplug_slot->private);
607         kfree(bss_hotplug_slot);
608 }
609
610 static int sn_hotplug_slot_register(struct pci_bus *pci_bus)
611 {
612         int device;
613         struct pci_slot *pci_slot;
614         struct hotplug_slot *bss_hotplug_slot;
615         char name[SN_SLOT_NAME_SIZE];
616         int rc = 0;
617
618         /*
619          * Currently only four devices are supported,
620          * in the future there maybe more -- up to 32.
621          */
622
623         for (device = 0; device < SN_MAX_HP_SLOTS ; device++) {
624                 if (sn_pci_slot_valid(pci_bus, device) != 1)
625                         continue;
626
627                 bss_hotplug_slot = kzalloc(sizeof(*bss_hotplug_slot),
628                                            GFP_KERNEL);
629                 if (!bss_hotplug_slot) {
630                         rc = -ENOMEM;
631                         goto alloc_err;
632                 }
633
634                 bss_hotplug_slot->info =
635                         kzalloc(sizeof(struct hotplug_slot_info),
636                                 GFP_KERNEL);
637                 if (!bss_hotplug_slot->info) {
638                         rc = -ENOMEM;
639                         goto alloc_err;
640                 }
641
642                 if (sn_hp_slot_private_alloc(bss_hotplug_slot,
643                                              pci_bus, device, name)) {
644                         rc = -ENOMEM;
645                         goto alloc_err;
646                 }
647                 bss_hotplug_slot->ops = &sn_hotplug_slot_ops;
648                 bss_hotplug_slot->release = &sn_release_slot;
649
650                 rc = pci_hp_register(bss_hotplug_slot, pci_bus, device, name);
651                 if (rc)
652                         goto register_err;
653
654                 pci_slot = bss_hotplug_slot->pci_slot;
655                 rc = sysfs_create_file(&pci_slot->kobj,
656                                        &sn_slot_path_attr.attr);
657                 if (rc)
658                         goto register_err;
659         }
660         dev_dbg(&pci_bus->self->dev, "Registered bus with hotplug\n");
661         return rc;
662
663 register_err:
664         dev_dbg(&pci_bus->self->dev, "bus failed to register with err = %d\n",
665                 rc);
666
667 alloc_err:
668         if (rc == -ENOMEM)
669                 dev_dbg(&pci_bus->self->dev, "Memory allocation error\n");
670
671         /* destroy THIS element */
672         if (bss_hotplug_slot)
673                 sn_release_slot(bss_hotplug_slot);
674
675         /* destroy anything else on the list */
676         while ((bss_hotplug_slot = sn_hp_destroy()))
677                 pci_hp_deregister(bss_hotplug_slot);
678
679         return rc;
680 }
681
682 static int sn_pci_hotplug_init(void)
683 {
684         struct pci_bus *pci_bus = NULL;
685         int rc;
686         int registered = 0;
687
688         if (!sn_prom_feature_available(PRF_HOTPLUG_SUPPORT)) {
689                 printk(KERN_ERR "%s: PROM version does not support hotplug.\n",
690                        __func__);
691                 return -EPERM;
692         }
693
694         INIT_LIST_HEAD(&sn_hp_list);
695
696         while ((pci_bus = pci_find_next_bus(pci_bus))) {
697                 if (!pci_bus->sysdata)
698                         continue;
699
700                 rc = sn_pci_bus_valid(pci_bus);
701                 if (rc != 1) {
702                         dev_dbg(&pci_bus->self->dev, "not a valid hotplug bus\n");
703                         continue;
704                 }
705                 dev_dbg(&pci_bus->self->dev, "valid hotplug bus\n");
706
707                 rc = sn_hotplug_slot_register(pci_bus);
708                 if (!rc) {
709                         registered = 1;
710                 } else {
711                         registered = 0;
712                         break;
713                 }
714         }
715
716         return registered == 1 ? 0 : -ENODEV;
717 }
718
719 static void sn_pci_hotplug_exit(void)
720 {
721         struct hotplug_slot *bss_hotplug_slot;
722
723         while ((bss_hotplug_slot = sn_hp_destroy()))
724                 pci_hp_deregister(bss_hotplug_slot);
725
726         if (!list_empty(&sn_hp_list))
727                 printk(KERN_ERR "%s: internal list is not empty\n", __FILE__);
728 }
729
730 module_init(sn_pci_hotplug_init);
731 module_exit(sn_pci_hotplug_exit);