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