V4L/DVB (7668): soc-camera: Remove redundant return
[linux-2.6] / 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 {
166         struct pcibus_info *pcibus_info;
167         struct slot *slot;
168
169         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(pci_bus);
170
171         slot = kzalloc(sizeof(*slot), GFP_KERNEL);
172         if (!slot)
173                 return -ENOMEM;
174         bss_hotplug_slot->private = slot;
175
176         bss_hotplug_slot->name = kmalloc(SN_SLOT_NAME_SIZE, GFP_KERNEL);
177         if (!bss_hotplug_slot->name) {
178                 kfree(bss_hotplug_slot->private);
179                 return -ENOMEM;
180         }
181
182         slot->device_num = device;
183         slot->pci_bus = pci_bus;
184         sprintf(bss_hotplug_slot->name, "%04x:%02x:%02x",
185                 pci_domain_nr(pci_bus),
186                 ((u16)pcibus_info->pbi_buscommon.bs_persist_busnum),
187                 device + 1);
188
189         sn_generate_path(pci_bus, slot->physical_path);
190
191         slot->hotplug_slot = bss_hotplug_slot;
192         list_add(&slot->hp_list, &sn_hp_list);
193
194         return 0;
195 }
196
197 static struct hotplug_slot * sn_hp_destroy(void)
198 {
199         struct slot *slot;
200         struct hotplug_slot *bss_hotplug_slot = NULL;
201
202         list_for_each_entry(slot, &sn_hp_list, hp_list) {
203                 bss_hotplug_slot = slot->hotplug_slot;
204                 list_del(&((struct slot *)bss_hotplug_slot->private)->
205                          hp_list);
206                 sysfs_remove_file(&bss_hotplug_slot->kobj,
207                                   &sn_slot_path_attr.attr);
208                 break;
209         }
210         return bss_hotplug_slot;
211 }
212
213 static void sn_bus_free_data(struct pci_dev *dev)
214 {
215         struct pci_bus *subordinate_bus;
216         struct pci_dev *child;
217
218         /* Recursively clean up sn_irq_info structs */
219         if (dev->subordinate) {
220                 subordinate_bus = dev->subordinate;
221                 list_for_each_entry(child, &subordinate_bus->devices, bus_list)
222                         sn_bus_free_data(child);
223         }
224         /*
225          * Some drivers may use dma accesses during the
226          * driver remove function. We release the sysdata
227          * areas after the driver remove functions have
228          * been called.
229          */
230         sn_bus_store_sysdata(dev);
231         sn_pci_unfixup_slot(dev);
232 }
233
234 static int sn_slot_enable(struct hotplug_slot *bss_hotplug_slot,
235                           int device_num, char **ssdt)
236 {
237         struct slot *slot = bss_hotplug_slot->private;
238         struct pcibus_info *pcibus_info;
239         struct pcibr_slot_enable_resp resp;
240         int rc;
241
242         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
243
244         /*
245          * Power-on and initialize the slot in the SN
246          * PCI infrastructure.
247          */
248         rc = sal_pcibr_slot_enable(pcibus_info, device_num, &resp, ssdt);
249
250
251         if (rc == PCI_SLOT_ALREADY_UP) {
252                 dev_dbg(&slot->pci_bus->self->dev, "is already active\n");
253                 return 1; /* return 1 to user */
254         }
255
256         if (rc == PCI_L1_ERR) {
257                 dev_dbg(&slot->pci_bus->self->dev,
258                         "L1 failure %d with message: %s",
259                         resp.resp_sub_errno, resp.resp_l1_msg);
260                 return -EPERM;
261         }
262
263         if (rc) {
264                 dev_dbg(&slot->pci_bus->self->dev,
265                         "insert failed with error %d sub-error %d\n",
266                         rc, resp.resp_sub_errno);
267                 return -EIO;
268         }
269
270         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
271         pcibus_info->pbi_enabled_devices |= (1 << device_num);
272
273         return 0;
274 }
275
276 static int sn_slot_disable(struct hotplug_slot *bss_hotplug_slot,
277                            int device_num, int action)
278 {
279         struct slot *slot = bss_hotplug_slot->private;
280         struct pcibus_info *pcibus_info;
281         struct pcibr_slot_disable_resp resp;
282         int rc;
283
284         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
285
286         rc = sal_pcibr_slot_disable(pcibus_info, device_num, action, &resp);
287
288         if ((action == PCI_REQ_SLOT_ELIGIBLE) &&
289             (rc == PCI_SLOT_ALREADY_DOWN)) {
290                 dev_dbg(&slot->pci_bus->self->dev, "Slot %s already inactive\n", slot->physical_path);
291                 return 1; /* return 1 to user */
292         }
293
294         if ((action == PCI_REQ_SLOT_ELIGIBLE) && (rc == PCI_EMPTY_33MHZ)) {
295                 dev_dbg(&slot->pci_bus->self->dev,
296                         "Cannot remove last 33MHz card\n");
297                 return -EPERM;
298         }
299
300         if ((action == PCI_REQ_SLOT_ELIGIBLE) && (rc == PCI_L1_ERR)) {
301                 dev_dbg(&slot->pci_bus->self->dev,
302                         "L1 failure %d with message \n%s\n",
303                         resp.resp_sub_errno, resp.resp_l1_msg);
304                 return -EPERM;
305         }
306
307         if ((action == PCI_REQ_SLOT_ELIGIBLE) && rc) {
308                 dev_dbg(&slot->pci_bus->self->dev,
309                         "remove failed with error %d sub-error %d\n",
310                         rc, resp.resp_sub_errno);
311                 return -EIO;
312         }
313
314         if ((action == PCI_REQ_SLOT_ELIGIBLE) && !rc)
315                 return 0;
316
317         if ((action == PCI_REQ_SLOT_DISABLE) && !rc) {
318                 pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
319                 pcibus_info->pbi_enabled_devices &= ~(1 << device_num);
320                 dev_dbg(&slot->pci_bus->self->dev, "remove successful\n");
321                 return 0;
322         }
323
324         if ((action == PCI_REQ_SLOT_DISABLE) && rc) {
325                 dev_dbg(&slot->pci_bus->self->dev,"remove failed rc = %d\n", rc);
326         }
327
328         return rc;
329 }
330
331 /*
332  * Power up and configure the slot via a SAL call to PROM.
333  * Scan slot (and any children), do any platform specific fixup,
334  * and find device driver.
335  */
336 static int enable_slot(struct hotplug_slot *bss_hotplug_slot)
337 {
338         struct slot *slot = bss_hotplug_slot->private;
339         struct pci_bus *new_bus = NULL;
340         struct pci_dev *dev;
341         int func, num_funcs;
342         int new_ppb = 0;
343         int rc;
344         char *ssdt = NULL;
345         void pcibios_fixup_device_resources(struct pci_dev *);
346
347         /* Serialize the Linux PCI infrastructure */
348         mutex_lock(&sn_hotplug_mutex);
349
350         /*
351          * Power-on and initialize the slot in the SN
352          * PCI infrastructure. Also, retrieve the ACPI SSDT
353          * table for the slot (if ACPI capable PROM).
354          */
355         rc = sn_slot_enable(bss_hotplug_slot, slot->device_num, &ssdt);
356         if (rc) {
357                 mutex_unlock(&sn_hotplug_mutex);
358                 return rc;
359         }
360
361         if (ssdt)
362                 ssdt = __va(ssdt);
363         /* Add the new SSDT for the slot to the ACPI namespace */
364         if (SN_ACPI_BASE_SUPPORT() && ssdt) {
365                 acpi_status ret;
366
367                 ret = acpi_load_table((struct acpi_table_header *)ssdt);
368                 if (ACPI_FAILURE(ret)) {
369                         printk(KERN_ERR "%s: acpi_load_table failed (0x%x)\n",
370                                __func__, ret);
371                         /* try to continue on */
372                 }
373         }
374
375         num_funcs = pci_scan_slot(slot->pci_bus,
376                                   PCI_DEVFN(slot->device_num + 1, 0));
377         if (!num_funcs) {
378                 dev_dbg(&slot->pci_bus->self->dev, "no device in slot\n");
379                 mutex_unlock(&sn_hotplug_mutex);
380                 return -ENODEV;
381         }
382
383         /*
384          * Map SN resources for all functions on the card
385          * to the Linux PCI interface and tell the drivers
386          * about them.
387          */
388         for (func = 0; func < num_funcs;  func++) {
389                 dev = pci_get_slot(slot->pci_bus,
390                                    PCI_DEVFN(slot->device_num + 1,
391                                              PCI_FUNC(func)));
392                 if (dev) {
393                         /* Need to do slot fixup on PPB before fixup of children
394                          * (PPB's pcidev_info needs to be in pcidev_info list
395                          * before child's SN_PCIDEV_INFO() call to setup
396                          * pdi_host_pcidev_info).
397                          */
398                         pcibios_fixup_device_resources(dev);
399                         if (SN_ACPI_BASE_SUPPORT())
400                                 sn_acpi_slot_fixup(dev);
401                         else
402                                 sn_io_slot_fixup(dev);
403                         if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
404                                 unsigned char sec_bus;
405                                 pci_read_config_byte(dev, PCI_SECONDARY_BUS,
406                                                      &sec_bus);
407                                 new_bus = pci_add_new_bus(dev->bus, dev,
408                                                           sec_bus);
409                                 pci_scan_child_bus(new_bus);
410                                 new_ppb = 1;
411                         }
412                         pci_dev_put(dev);
413                 }
414         }
415
416         /*
417          * Add the slot's devices to the ACPI infrastructure */
418         if (SN_ACPI_BASE_SUPPORT() && ssdt) {
419                 unsigned long adr;
420                 struct acpi_device *pdevice;
421                 struct acpi_device *device;
422                 acpi_handle phandle;
423                 acpi_handle chandle = NULL;
424                 acpi_handle rethandle;
425                 acpi_status ret;
426
427                 phandle = PCI_CONTROLLER(slot->pci_bus)->acpi_handle;
428
429                 if (acpi_bus_get_device(phandle, &pdevice)) {
430                         dev_dbg(&slot->pci_bus->self->dev,
431                                 "no parent device, assuming NULL\n");
432                         pdevice = NULL;
433                 }
434
435                 /*
436                  * Walk the rootbus node's immediate children looking for
437                  * the slot's device node(s). There can be more than
438                  * one for multifunction devices.
439                  */
440                 for (;;) {
441                         rethandle = NULL;
442                         ret = acpi_get_next_object(ACPI_TYPE_DEVICE,
443                                                    phandle, chandle,
444                                                    &rethandle);
445
446                         if (ret == AE_NOT_FOUND || rethandle == NULL)
447                                 break;
448
449                         chandle = rethandle;
450
451                         ret = acpi_evaluate_integer(chandle, METHOD_NAME__ADR,
452                                                     NULL, &adr);
453
454                         if (ACPI_SUCCESS(ret) &&
455                             (adr>>16) == (slot->device_num + 1)) {
456
457                                 ret = acpi_bus_add(&device, pdevice, chandle,
458                                                    ACPI_BUS_TYPE_DEVICE);
459                                 if (ACPI_FAILURE(ret)) {
460                                         printk(KERN_ERR "%s: acpi_bus_add "
461                                                "failed (0x%x) for slot %d "
462                                                "func %d\n", __func__,
463                                                ret, (int)(adr>>16),
464                                                (int)(adr&0xffff));
465                                         /* try to continue on */
466                                 } else {
467                                         acpi_bus_start(device);
468                                 }
469                         }
470                 }
471         }
472
473         /* Call the driver for the new device */
474         pci_bus_add_devices(slot->pci_bus);
475         /* Call the drivers for the new devices subordinate to PPB */
476         if (new_ppb)
477                 pci_bus_add_devices(new_bus);
478
479         mutex_unlock(&sn_hotplug_mutex);
480
481         if (rc == 0)
482                 dev_dbg(&slot->pci_bus->self->dev,
483                         "insert operation successful\n");
484         else
485                 dev_dbg(&slot->pci_bus->self->dev,
486                         "insert operation failed rc = %d\n", rc);
487
488         return rc;
489 }
490
491 static int disable_slot(struct hotplug_slot *bss_hotplug_slot)
492 {
493         struct slot *slot = bss_hotplug_slot->private;
494         struct pci_dev *dev;
495         int func;
496         int rc;
497         acpi_owner_id ssdt_id = 0;
498
499         /* Acquire update access to the bus */
500         mutex_lock(&sn_hotplug_mutex);
501
502         /* is it okay to bring this slot down? */
503         rc = sn_slot_disable(bss_hotplug_slot, slot->device_num,
504                              PCI_REQ_SLOT_ELIGIBLE);
505         if (rc)
506                 goto leaving;
507
508         /* free the ACPI resources for the slot */
509         if (SN_ACPI_BASE_SUPPORT() &&
510             PCI_CONTROLLER(slot->pci_bus)->acpi_handle) {
511                 unsigned long adr;
512                 struct acpi_device *device;
513                 acpi_handle phandle;
514                 acpi_handle chandle = NULL;
515                 acpi_handle rethandle;
516                 acpi_status ret;
517
518                 /* Get the rootbus node pointer */
519                 phandle = PCI_CONTROLLER(slot->pci_bus)->acpi_handle;
520
521                 /*
522                  * Walk the rootbus node's immediate children looking for
523                  * the slot's device node(s). There can be more than
524                  * one for multifunction devices.
525                  */
526                 for (;;) {
527                         rethandle = NULL;
528                         ret = acpi_get_next_object(ACPI_TYPE_DEVICE,
529                                                    phandle, chandle,
530                                                    &rethandle);
531
532                         if (ret == AE_NOT_FOUND || rethandle == NULL)
533                                 break;
534
535                         chandle = rethandle;
536
537                         ret = acpi_evaluate_integer(chandle,
538                                                     METHOD_NAME__ADR,
539                                                     NULL, &adr);
540                         if (ACPI_SUCCESS(ret) &&
541                             (adr>>16) == (slot->device_num + 1)) {
542                                 /* retain the owner id */
543                                 acpi_get_id(chandle, &ssdt_id);
544
545                                 ret = acpi_bus_get_device(chandle,
546                                                           &device);
547                                 if (ACPI_SUCCESS(ret))
548                                         acpi_bus_trim(device, 1);
549                         }
550                 }
551
552         }
553
554         /* Free the SN resources assigned to the Linux device.*/
555         for (func = 0; func < 8;  func++) {
556                 dev = pci_get_slot(slot->pci_bus,
557                                    PCI_DEVFN(slot->device_num + 1,
558                                              PCI_FUNC(func)));
559                 if (dev) {
560                         sn_bus_free_data(dev);
561                         pci_remove_bus_device(dev);
562                         pci_dev_put(dev);
563                 }
564         }
565
566         /* Remove the SSDT for the slot from the ACPI namespace */
567         if (SN_ACPI_BASE_SUPPORT() && ssdt_id) {
568                 acpi_status ret;
569                 ret = acpi_unload_table_id(ssdt_id);
570                 if (ACPI_FAILURE(ret)) {
571                         printk(KERN_ERR "%s: acpi_unload_table_id "
572                                "failed (0x%x) for id %d\n",
573                                __func__, ret, ssdt_id);
574                         /* try to continue on */
575                 }
576         }
577
578         /* free the collected sysdata pointers */
579         sn_bus_free_sysdata();
580
581         /* Deactivate slot */
582         rc = sn_slot_disable(bss_hotplug_slot, slot->device_num,
583                              PCI_REQ_SLOT_DISABLE);
584  leaving:
585         /* Release the bus lock */
586         mutex_unlock(&sn_hotplug_mutex);
587
588         return rc;
589 }
590
591 static inline int get_power_status(struct hotplug_slot *bss_hotplug_slot,
592                                    u8 *value)
593 {
594         struct slot *slot = bss_hotplug_slot->private;
595         struct pcibus_info *pcibus_info;
596         u32 power;
597
598         pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
599         mutex_lock(&sn_hotplug_mutex);
600         power = pcibus_info->pbi_enabled_devices & (1 << slot->device_num);
601         *value = power ? 1 : 0;
602         mutex_unlock(&sn_hotplug_mutex);
603         return 0;
604 }
605
606 static void sn_release_slot(struct hotplug_slot *bss_hotplug_slot)
607 {
608         kfree(bss_hotplug_slot->info);
609         kfree(bss_hotplug_slot->name);
610         kfree(bss_hotplug_slot->private);
611         kfree(bss_hotplug_slot);
612 }
613
614 static int sn_hotplug_slot_register(struct pci_bus *pci_bus)
615 {
616         int device;
617         struct hotplug_slot *bss_hotplug_slot;
618         int rc = 0;
619
620         /*
621          * Currently only four devices are supported,
622          * in the future there maybe more -- up to 32.
623          */
624
625         for (device = 0; device < SN_MAX_HP_SLOTS ; device++) {
626                 if (sn_pci_slot_valid(pci_bus, device) != 1)
627                         continue;
628
629                 bss_hotplug_slot = kzalloc(sizeof(*bss_hotplug_slot),
630                                            GFP_KERNEL);
631                 if (!bss_hotplug_slot) {
632                         rc = -ENOMEM;
633                         goto alloc_err;
634                 }
635
636                 bss_hotplug_slot->info =
637                         kzalloc(sizeof(struct hotplug_slot_info),
638                                 GFP_KERNEL);
639                 if (!bss_hotplug_slot->info) {
640                         rc = -ENOMEM;
641                         goto alloc_err;
642                 }
643
644                 if (sn_hp_slot_private_alloc(bss_hotplug_slot,
645                                              pci_bus, device)) {
646                         rc = -ENOMEM;
647                         goto alloc_err;
648                 }
649
650                 bss_hotplug_slot->ops = &sn_hotplug_slot_ops;
651                 bss_hotplug_slot->release = &sn_release_slot;
652
653                 rc = pci_hp_register(bss_hotplug_slot);
654                 if (rc)
655                         goto register_err;
656
657                 rc = sysfs_create_file(&bss_hotplug_slot->kobj,
658                                        &sn_slot_path_attr.attr);
659                 if (rc)
660                         goto register_err;
661         }
662         dev_dbg(&pci_bus->self->dev, "Registered bus with hotplug\n");
663         return rc;
664
665 register_err:
666         dev_dbg(&pci_bus->self->dev, "bus failed to register with err = %d\n",
667                 rc);
668
669 alloc_err:
670         if (rc == -ENOMEM)
671                 dev_dbg(&pci_bus->self->dev, "Memory allocation error\n");
672
673         /* destroy THIS element */
674         if (bss_hotplug_slot)
675                 sn_release_slot(bss_hotplug_slot);
676
677         /* destroy anything else on the list */
678         while ((bss_hotplug_slot = sn_hp_destroy()))
679                 pci_hp_deregister(bss_hotplug_slot);
680
681         return rc;
682 }
683
684 static int sn_pci_hotplug_init(void)
685 {
686         struct pci_bus *pci_bus = NULL;
687         int rc;
688         int registered = 0;
689
690         if (!sn_prom_feature_available(PRF_HOTPLUG_SUPPORT)) {
691                 printk(KERN_ERR "%s: PROM version does not support hotplug.\n",
692                        __func__);
693                 return -EPERM;
694         }
695
696         INIT_LIST_HEAD(&sn_hp_list);
697
698         while ((pci_bus = pci_find_next_bus(pci_bus))) {
699                 if (!pci_bus->sysdata)
700                         continue;
701
702                 rc = sn_pci_bus_valid(pci_bus);
703                 if (rc != 1) {
704                         dev_dbg(&pci_bus->self->dev, "not a valid hotplug bus\n");
705                         continue;
706                 }
707                 dev_dbg(&pci_bus->self->dev, "valid hotplug bus\n");
708
709                 rc = sn_hotplug_slot_register(pci_bus);
710                 if (!rc) {
711                         registered = 1;
712                 } else {
713                         registered = 0;
714                         break;
715                 }
716         }
717
718         return registered == 1 ? 0 : -ENODEV;
719 }
720
721 static void sn_pci_hotplug_exit(void)
722 {
723         struct hotplug_slot *bss_hotplug_slot;
724
725         while ((bss_hotplug_slot = sn_hp_destroy()))
726                 pci_hp_deregister(bss_hotplug_slot);
727
728         if (!list_empty(&sn_hp_list))
729                 printk(KERN_ERR "%s: internal list is not empty\n", __FILE__);
730 }
731
732 module_init(sn_pci_hotplug_init);
733 module_exit(sn_pci_hotplug_exit);