xref: /linux/drivers/acpi/pci_root.c (revision a078ccff5642a8fe792a43b3d973bcc3f6dd733f)
1 /*
2  *  pci_root.c - ACPI PCI Root Bridge Driver ($Revision: 40 $)
3  *
4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6  *
7  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
8  *
9  *  This program is free software; you can redistribute it and/or modify
10  *  it under the terms of the GNU General Public License as published by
11  *  the Free Software Foundation; either version 2 of the License, or (at
12  *  your option) any later version.
13  *
14  *  This program is distributed in the hope that it will be useful, but
15  *  WITHOUT ANY WARRANTY; without even the implied warranty of
16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17  *  General Public License for more details.
18  *
19  *  You should have received a copy of the GNU General Public License along
20  *  with this program; if not, write to the Free Software Foundation, Inc.,
21  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
22  *
23  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
24  */
25 
26 #include <linux/kernel.h>
27 #include <linux/module.h>
28 #include <linux/init.h>
29 #include <linux/types.h>
30 #include <linux/mutex.h>
31 #include <linux/pm.h>
32 #include <linux/pm_runtime.h>
33 #include <linux/pci.h>
34 #include <linux/pci-acpi.h>
35 #include <linux/pci-aspm.h>
36 #include <linux/acpi.h>
37 #include <linux/slab.h>
38 #include <acpi/acpi_bus.h>
39 #include <acpi/acpi_drivers.h>
40 #include <acpi/apei.h>
41 
42 #define PREFIX "ACPI: "
43 
44 #define _COMPONENT		ACPI_PCI_COMPONENT
45 ACPI_MODULE_NAME("pci_root");
46 #define ACPI_PCI_ROOT_CLASS		"pci_bridge"
47 #define ACPI_PCI_ROOT_DEVICE_NAME	"PCI Root Bridge"
48 static int acpi_pci_root_add(struct acpi_device *device,
49 			     const struct acpi_device_id *not_used);
50 static void acpi_pci_root_remove(struct acpi_device *device);
51 
52 #define ACPI_PCIE_REQ_SUPPORT (OSC_EXT_PCI_CONFIG_SUPPORT \
53 				| OSC_ACTIVE_STATE_PWR_SUPPORT \
54 				| OSC_CLOCK_PWR_CAPABILITY_SUPPORT \
55 				| OSC_MSI_SUPPORT)
56 
57 static const struct acpi_device_id root_device_ids[] = {
58 	{"PNP0A03", 0},
59 	{"", 0},
60 };
61 
62 static struct acpi_scan_handler pci_root_handler = {
63 	.ids = root_device_ids,
64 	.attach = acpi_pci_root_add,
65 	.detach = acpi_pci_root_remove,
66 };
67 
68 /* Lock to protect both acpi_pci_roots and acpi_pci_drivers lists */
69 static DEFINE_MUTEX(acpi_pci_root_lock);
70 static LIST_HEAD(acpi_pci_roots);
71 static LIST_HEAD(acpi_pci_drivers);
72 
73 static DEFINE_MUTEX(osc_lock);
74 
75 int acpi_pci_register_driver(struct acpi_pci_driver *driver)
76 {
77 	int n = 0;
78 	struct acpi_pci_root *root;
79 
80 	mutex_lock(&acpi_pci_root_lock);
81 	list_add_tail(&driver->node, &acpi_pci_drivers);
82 	if (driver->add)
83 		list_for_each_entry(root, &acpi_pci_roots, node) {
84 			driver->add(root);
85 			n++;
86 		}
87 	mutex_unlock(&acpi_pci_root_lock);
88 
89 	return n;
90 }
91 EXPORT_SYMBOL(acpi_pci_register_driver);
92 
93 void acpi_pci_unregister_driver(struct acpi_pci_driver *driver)
94 {
95 	struct acpi_pci_root *root;
96 
97 	mutex_lock(&acpi_pci_root_lock);
98 	list_del(&driver->node);
99 	if (driver->remove)
100 		list_for_each_entry(root, &acpi_pci_roots, node)
101 			driver->remove(root);
102 	mutex_unlock(&acpi_pci_root_lock);
103 }
104 EXPORT_SYMBOL(acpi_pci_unregister_driver);
105 
106 /**
107  * acpi_is_root_bridge - determine whether an ACPI CA node is a PCI root bridge
108  * @handle - the ACPI CA node in question.
109  *
110  * Note: we could make this API take a struct acpi_device * instead, but
111  * for now, it's more convenient to operate on an acpi_handle.
112  */
113 int acpi_is_root_bridge(acpi_handle handle)
114 {
115 	int ret;
116 	struct acpi_device *device;
117 
118 	ret = acpi_bus_get_device(handle, &device);
119 	if (ret)
120 		return 0;
121 
122 	ret = acpi_match_device_ids(device, root_device_ids);
123 	if (ret)
124 		return 0;
125 	else
126 		return 1;
127 }
128 EXPORT_SYMBOL_GPL(acpi_is_root_bridge);
129 
130 static acpi_status
131 get_root_bridge_busnr_callback(struct acpi_resource *resource, void *data)
132 {
133 	struct resource *res = data;
134 	struct acpi_resource_address64 address;
135 
136 	if (resource->type != ACPI_RESOURCE_TYPE_ADDRESS16 &&
137 	    resource->type != ACPI_RESOURCE_TYPE_ADDRESS32 &&
138 	    resource->type != ACPI_RESOURCE_TYPE_ADDRESS64)
139 		return AE_OK;
140 
141 	acpi_resource_to_address64(resource, &address);
142 	if ((address.address_length > 0) &&
143 	    (address.resource_type == ACPI_BUS_NUMBER_RANGE)) {
144 		res->start = address.minimum;
145 		res->end = address.minimum + address.address_length - 1;
146 	}
147 
148 	return AE_OK;
149 }
150 
151 static acpi_status try_get_root_bridge_busnr(acpi_handle handle,
152 					     struct resource *res)
153 {
154 	acpi_status status;
155 
156 	res->start = -1;
157 	status =
158 	    acpi_walk_resources(handle, METHOD_NAME__CRS,
159 				get_root_bridge_busnr_callback, res);
160 	if (ACPI_FAILURE(status))
161 		return status;
162 	if (res->start == -1)
163 		return AE_ERROR;
164 	return AE_OK;
165 }
166 
167 static u8 pci_osc_uuid_str[] = "33DB4D5B-1FF7-401C-9657-7441C03DD766";
168 
169 static acpi_status acpi_pci_run_osc(acpi_handle handle,
170 				    const u32 *capbuf, u32 *retval)
171 {
172 	struct acpi_osc_context context = {
173 		.uuid_str = pci_osc_uuid_str,
174 		.rev = 1,
175 		.cap.length = 12,
176 		.cap.pointer = (void *)capbuf,
177 	};
178 	acpi_status status;
179 
180 	status = acpi_run_osc(handle, &context);
181 	if (ACPI_SUCCESS(status)) {
182 		*retval = *((u32 *)(context.ret.pointer + 8));
183 		kfree(context.ret.pointer);
184 	}
185 	return status;
186 }
187 
188 static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root,
189 					u32 support,
190 					u32 *control)
191 {
192 	acpi_status status;
193 	u32 result, capbuf[3];
194 
195 	support &= OSC_PCI_SUPPORT_MASKS;
196 	support |= root->osc_support_set;
197 
198 	capbuf[OSC_QUERY_TYPE] = OSC_QUERY_ENABLE;
199 	capbuf[OSC_SUPPORT_TYPE] = support;
200 	if (control) {
201 		*control &= OSC_PCI_CONTROL_MASKS;
202 		capbuf[OSC_CONTROL_TYPE] = *control | root->osc_control_set;
203 	} else {
204 		/* Run _OSC query for all possible controls. */
205 		capbuf[OSC_CONTROL_TYPE] = OSC_PCI_CONTROL_MASKS;
206 	}
207 
208 	status = acpi_pci_run_osc(root->device->handle, capbuf, &result);
209 	if (ACPI_SUCCESS(status)) {
210 		root->osc_support_set = support;
211 		if (control)
212 			*control = result;
213 	}
214 	return status;
215 }
216 
217 static acpi_status acpi_pci_osc_support(struct acpi_pci_root *root, u32 flags)
218 {
219 	acpi_status status;
220 	acpi_handle tmp;
221 
222 	status = acpi_get_handle(root->device->handle, "_OSC", &tmp);
223 	if (ACPI_FAILURE(status))
224 		return status;
225 	mutex_lock(&osc_lock);
226 	status = acpi_pci_query_osc(root, flags, NULL);
227 	mutex_unlock(&osc_lock);
228 	return status;
229 }
230 
231 struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)
232 {
233 	struct acpi_pci_root *root;
234 	struct acpi_device *device;
235 
236 	if (acpi_bus_get_device(handle, &device) ||
237 	    acpi_match_device_ids(device, root_device_ids))
238 		return NULL;
239 
240 	root = acpi_driver_data(device);
241 
242 	return root;
243 }
244 EXPORT_SYMBOL_GPL(acpi_pci_find_root);
245 
246 struct acpi_handle_node {
247 	struct list_head node;
248 	acpi_handle handle;
249 };
250 
251 /**
252  * acpi_get_pci_dev - convert ACPI CA handle to struct pci_dev
253  * @handle: the handle in question
254  *
255  * Given an ACPI CA handle, the desired PCI device is located in the
256  * list of PCI devices.
257  *
258  * If the device is found, its reference count is increased and this
259  * function returns a pointer to its data structure.  The caller must
260  * decrement the reference count by calling pci_dev_put().
261  * If no device is found, %NULL is returned.
262  */
263 struct pci_dev *acpi_get_pci_dev(acpi_handle handle)
264 {
265 	int dev, fn;
266 	unsigned long long adr;
267 	acpi_status status;
268 	acpi_handle phandle;
269 	struct pci_bus *pbus;
270 	struct pci_dev *pdev = NULL;
271 	struct acpi_handle_node *node, *tmp;
272 	struct acpi_pci_root *root;
273 	LIST_HEAD(device_list);
274 
275 	/*
276 	 * Walk up the ACPI CA namespace until we reach a PCI root bridge.
277 	 */
278 	phandle = handle;
279 	while (!acpi_is_root_bridge(phandle)) {
280 		node = kzalloc(sizeof(struct acpi_handle_node), GFP_KERNEL);
281 		if (!node)
282 			goto out;
283 
284 		INIT_LIST_HEAD(&node->node);
285 		node->handle = phandle;
286 		list_add(&node->node, &device_list);
287 
288 		status = acpi_get_parent(phandle, &phandle);
289 		if (ACPI_FAILURE(status))
290 			goto out;
291 	}
292 
293 	root = acpi_pci_find_root(phandle);
294 	if (!root)
295 		goto out;
296 
297 	pbus = root->bus;
298 
299 	/*
300 	 * Now, walk back down the PCI device tree until we return to our
301 	 * original handle. Assumes that everything between the PCI root
302 	 * bridge and the device we're looking for must be a P2P bridge.
303 	 */
304 	list_for_each_entry(node, &device_list, node) {
305 		acpi_handle hnd = node->handle;
306 		status = acpi_evaluate_integer(hnd, "_ADR", NULL, &adr);
307 		if (ACPI_FAILURE(status))
308 			goto out;
309 		dev = (adr >> 16) & 0xffff;
310 		fn  = adr & 0xffff;
311 
312 		pdev = pci_get_slot(pbus, PCI_DEVFN(dev, fn));
313 		if (!pdev || hnd == handle)
314 			break;
315 
316 		pbus = pdev->subordinate;
317 		pci_dev_put(pdev);
318 
319 		/*
320 		 * This function may be called for a non-PCI device that has a
321 		 * PCI parent (eg. a disk under a PCI SATA controller).  In that
322 		 * case pdev->subordinate will be NULL for the parent.
323 		 */
324 		if (!pbus) {
325 			dev_dbg(&pdev->dev, "Not a PCI-to-PCI bridge\n");
326 			pdev = NULL;
327 			break;
328 		}
329 	}
330 out:
331 	list_for_each_entry_safe(node, tmp, &device_list, node)
332 		kfree(node);
333 
334 	return pdev;
335 }
336 EXPORT_SYMBOL_GPL(acpi_get_pci_dev);
337 
338 /**
339  * acpi_pci_osc_control_set - Request control of PCI root _OSC features.
340  * @handle: ACPI handle of a PCI root bridge (or PCIe Root Complex).
341  * @mask: Mask of _OSC bits to request control of, place to store control mask.
342  * @req: Mask of _OSC bits the control of is essential to the caller.
343  *
344  * Run _OSC query for @mask and if that is successful, compare the returned
345  * mask of control bits with @req.  If all of the @req bits are set in the
346  * returned mask, run _OSC request for it.
347  *
348  * The variable at the @mask address may be modified regardless of whether or
349  * not the function returns success.  On success it will contain the mask of
350  * _OSC bits the BIOS has granted control of, but its contents are meaningless
351  * on failure.
352  **/
353 acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 req)
354 {
355 	struct acpi_pci_root *root;
356 	acpi_status status;
357 	u32 ctrl, capbuf[3];
358 	acpi_handle tmp;
359 
360 	if (!mask)
361 		return AE_BAD_PARAMETER;
362 
363 	ctrl = *mask & OSC_PCI_CONTROL_MASKS;
364 	if ((ctrl & req) != req)
365 		return AE_TYPE;
366 
367 	root = acpi_pci_find_root(handle);
368 	if (!root)
369 		return AE_NOT_EXIST;
370 
371 	status = acpi_get_handle(handle, "_OSC", &tmp);
372 	if (ACPI_FAILURE(status))
373 		return status;
374 
375 	mutex_lock(&osc_lock);
376 
377 	*mask = ctrl | root->osc_control_set;
378 	/* No need to evaluate _OSC if the control was already granted. */
379 	if ((root->osc_control_set & ctrl) == ctrl)
380 		goto out;
381 
382 	/* Need to check the available controls bits before requesting them. */
383 	while (*mask) {
384 		status = acpi_pci_query_osc(root, root->osc_support_set, mask);
385 		if (ACPI_FAILURE(status))
386 			goto out;
387 		if (ctrl == *mask)
388 			break;
389 		ctrl = *mask;
390 	}
391 
392 	if ((ctrl & req) != req) {
393 		status = AE_SUPPORT;
394 		goto out;
395 	}
396 
397 	capbuf[OSC_QUERY_TYPE] = 0;
398 	capbuf[OSC_SUPPORT_TYPE] = root->osc_support_set;
399 	capbuf[OSC_CONTROL_TYPE] = ctrl;
400 	status = acpi_pci_run_osc(handle, capbuf, mask);
401 	if (ACPI_SUCCESS(status))
402 		root->osc_control_set = *mask;
403 out:
404 	mutex_unlock(&osc_lock);
405 	return status;
406 }
407 EXPORT_SYMBOL(acpi_pci_osc_control_set);
408 
409 static int acpi_pci_root_add(struct acpi_device *device,
410 			     const struct acpi_device_id *not_used)
411 {
412 	unsigned long long segment, bus;
413 	acpi_status status;
414 	int result;
415 	struct acpi_pci_root *root;
416 	struct acpi_pci_driver *driver;
417 	u32 flags, base_flags;
418 
419 	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
420 	if (!root)
421 		return -ENOMEM;
422 
423 	segment = 0;
424 	status = acpi_evaluate_integer(device->handle, METHOD_NAME__SEG, NULL,
425 				       &segment);
426 	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
427 		printk(KERN_ERR PREFIX "can't evaluate _SEG\n");
428 		result = -ENODEV;
429 		goto end;
430 	}
431 
432 	/* Check _CRS first, then _BBN.  If no _BBN, default to zero. */
433 	root->secondary.flags = IORESOURCE_BUS;
434 	status = try_get_root_bridge_busnr(device->handle, &root->secondary);
435 	if (ACPI_FAILURE(status)) {
436 		/*
437 		 * We need both the start and end of the downstream bus range
438 		 * to interpret _CBA (MMCONFIG base address), so it really is
439 		 * supposed to be in _CRS.  If we don't find it there, all we
440 		 * can do is assume [_BBN-0xFF] or [0-0xFF].
441 		 */
442 		root->secondary.end = 0xFF;
443 		printk(KERN_WARNING FW_BUG PREFIX
444 		       "no secondary bus range in _CRS\n");
445 		status = acpi_evaluate_integer(device->handle, METHOD_NAME__BBN,
446 					       NULL, &bus);
447 		if (ACPI_SUCCESS(status))
448 			root->secondary.start = bus;
449 		else if (status == AE_NOT_FOUND)
450 			root->secondary.start = 0;
451 		else {
452 			printk(KERN_ERR PREFIX "can't evaluate _BBN\n");
453 			result = -ENODEV;
454 			goto end;
455 		}
456 	}
457 
458 	INIT_LIST_HEAD(&root->node);
459 	root->device = device;
460 	root->segment = segment & 0xFFFF;
461 	strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME);
462 	strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
463 	device->driver_data = root;
464 
465 	printk(KERN_INFO PREFIX "%s [%s] (domain %04x %pR)\n",
466 	       acpi_device_name(device), acpi_device_bid(device),
467 	       root->segment, &root->secondary);
468 
469 	root->mcfg_addr = acpi_pci_root_get_mcfg_addr(device->handle);
470 
471 	/*
472 	 * All supported architectures that use ACPI have support for
473 	 * PCI domains, so we indicate this in _OSC support capabilities.
474 	 */
475 	flags = base_flags = OSC_PCI_SEGMENT_GROUPS_SUPPORT;
476 	acpi_pci_osc_support(root, flags);
477 
478 	/*
479 	 * TBD: Need PCI interface for enumeration/configuration of roots.
480 	 */
481 
482 	mutex_lock(&acpi_pci_root_lock);
483 	list_add_tail(&root->node, &acpi_pci_roots);
484 	mutex_unlock(&acpi_pci_root_lock);
485 
486 	/*
487 	 * Scan the Root Bridge
488 	 * --------------------
489 	 * Must do this prior to any attempt to bind the root device, as the
490 	 * PCI namespace does not get created until this call is made (and
491 	 * thus the root bridge's pci_dev does not exist).
492 	 */
493 	root->bus = pci_acpi_scan_root(root);
494 	if (!root->bus) {
495 		printk(KERN_ERR PREFIX
496 			    "Bus %04x:%02x not present in PCI namespace\n",
497 			    root->segment, (unsigned int)root->secondary.start);
498 		result = -ENODEV;
499 		goto out_del_root;
500 	}
501 
502 	/* Indicate support for various _OSC capabilities. */
503 	if (pci_ext_cfg_avail())
504 		flags |= OSC_EXT_PCI_CONFIG_SUPPORT;
505 	if (pcie_aspm_support_enabled()) {
506 		flags |= OSC_ACTIVE_STATE_PWR_SUPPORT |
507 		OSC_CLOCK_PWR_CAPABILITY_SUPPORT;
508 	}
509 	if (pci_msi_enabled())
510 		flags |= OSC_MSI_SUPPORT;
511 	if (flags != base_flags) {
512 		status = acpi_pci_osc_support(root, flags);
513 		if (ACPI_FAILURE(status)) {
514 			dev_info(&device->dev, "ACPI _OSC support "
515 				"notification failed, disabling PCIe ASPM\n");
516 			pcie_no_aspm();
517 			flags = base_flags;
518 		}
519 	}
520 
521 	if (!pcie_ports_disabled
522 	    && (flags & ACPI_PCIE_REQ_SUPPORT) == ACPI_PCIE_REQ_SUPPORT) {
523 		flags = OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL
524 			| OSC_PCI_EXPRESS_NATIVE_HP_CONTROL
525 			| OSC_PCI_EXPRESS_PME_CONTROL;
526 
527 		if (pci_aer_available()) {
528 			if (aer_acpi_firmware_first())
529 				dev_dbg(&device->dev,
530 					"PCIe errors handled by BIOS.\n");
531 			else
532 				flags |= OSC_PCI_EXPRESS_AER_CONTROL;
533 		}
534 
535 		dev_info(&device->dev,
536 			"Requesting ACPI _OSC control (0x%02x)\n", flags);
537 
538 		status = acpi_pci_osc_control_set(device->handle, &flags,
539 				       OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL);
540 		if (ACPI_SUCCESS(status)) {
541 			dev_info(&device->dev,
542 				"ACPI _OSC control (0x%02x) granted\n", flags);
543 			if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {
544 				/*
545 				 * We have ASPM control, but the FADT indicates
546 				 * that it's unsupported. Clear it.
547 				 */
548 				pcie_clear_aspm(root->bus);
549 			}
550 		} else {
551 			dev_info(&device->dev,
552 				"ACPI _OSC request failed (%s), "
553 				"returned control mask: 0x%02x\n",
554 				acpi_format_exception(status), flags);
555 			pr_info("ACPI _OSC control for PCIe not granted, "
556 				"disabling ASPM\n");
557 			pcie_no_aspm();
558 		}
559 	} else {
560 		dev_info(&device->dev,
561 			 "Unable to request _OSC control "
562 			 "(_OSC support mask: 0x%02x)\n", flags);
563 	}
564 
565 	pci_acpi_add_bus_pm_notifier(device, root->bus);
566 	if (device->wakeup.flags.run_wake)
567 		device_set_run_wake(root->bus->bridge, true);
568 
569 	if (system_state != SYSTEM_BOOTING) {
570 		pcibios_resource_survey_bus(root->bus);
571 		pci_assign_unassigned_bus_resources(root->bus);
572 	}
573 
574 	mutex_lock(&acpi_pci_root_lock);
575 	list_for_each_entry(driver, &acpi_pci_drivers, node)
576 		if (driver->add)
577 			driver->add(root);
578 	mutex_unlock(&acpi_pci_root_lock);
579 
580 	/* need to after hot-added ioapic is registered */
581 	if (system_state != SYSTEM_BOOTING)
582 		pci_enable_bridges(root->bus);
583 
584 	pci_bus_add_devices(root->bus);
585 	return 1;
586 
587 out_del_root:
588 	mutex_lock(&acpi_pci_root_lock);
589 	list_del(&root->node);
590 	mutex_unlock(&acpi_pci_root_lock);
591 
592 end:
593 	kfree(root);
594 	return result;
595 }
596 
597 static void acpi_pci_root_remove(struct acpi_device *device)
598 {
599 	struct acpi_pci_root *root = acpi_driver_data(device);
600 	struct acpi_pci_driver *driver;
601 
602 	pci_stop_root_bus(root->bus);
603 
604 	mutex_lock(&acpi_pci_root_lock);
605 	list_for_each_entry_reverse(driver, &acpi_pci_drivers, node)
606 		if (driver->remove)
607 			driver->remove(root);
608 	mutex_unlock(&acpi_pci_root_lock);
609 
610 	device_set_run_wake(root->bus->bridge, false);
611 	pci_acpi_remove_bus_pm_notifier(device);
612 
613 	pci_remove_root_bus(root->bus);
614 
615 	mutex_lock(&acpi_pci_root_lock);
616 	list_del(&root->node);
617 	mutex_unlock(&acpi_pci_root_lock);
618 	kfree(root);
619 }
620 
621 void __init acpi_pci_root_init(void)
622 {
623 	acpi_hest_init();
624 
625 	if (!acpi_pci_disabled) {
626 		pci_acpi_crs_quirks();
627 		acpi_scan_add_handler(&pci_root_handler);
628 	}
629 }
630 /* Support root bridge hotplug */
631 
632 static void handle_root_bridge_insertion(acpi_handle handle)
633 {
634 	struct acpi_device *device;
635 
636 	if (!acpi_bus_get_device(handle, &device)) {
637 		printk(KERN_DEBUG "acpi device exists...\n");
638 		return;
639 	}
640 
641 	if (acpi_bus_scan(handle))
642 		printk(KERN_ERR "cannot add bridge to acpi list\n");
643 }
644 
645 static void handle_root_bridge_removal(struct acpi_device *device)
646 {
647 	acpi_status status;
648 	struct acpi_eject_event *ej_event;
649 
650 	ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
651 	if (!ej_event) {
652 		/* Inform firmware the hot-remove operation has error */
653 		(void) acpi_evaluate_hotplug_ost(device->handle,
654 					ACPI_NOTIFY_EJECT_REQUEST,
655 					ACPI_OST_SC_NON_SPECIFIC_FAILURE,
656 					NULL);
657 		return;
658 	}
659 
660 	ej_event->device = device;
661 	ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
662 
663 	status = acpi_os_hotplug_execute(acpi_bus_hot_remove_device, ej_event);
664 	if (ACPI_FAILURE(status))
665 		kfree(ej_event);
666 }
667 
668 static void _handle_hotplug_event_root(struct work_struct *work)
669 {
670 	struct acpi_pci_root *root;
671 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER };
672 	struct acpi_hp_work *hp_work;
673 	acpi_handle handle;
674 	u32 type;
675 
676 	hp_work = container_of(work, struct acpi_hp_work, work);
677 	handle = hp_work->handle;
678 	type = hp_work->type;
679 
680 	acpi_scan_lock_acquire();
681 
682 	root = acpi_pci_find_root(handle);
683 	acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
684 
685 	switch (type) {
686 	case ACPI_NOTIFY_BUS_CHECK:
687 		/* bus enumerate */
688 		printk(KERN_DEBUG "%s: Bus check notify on %s\n", __func__,
689 				 (char *)buffer.pointer);
690 		if (!root)
691 			handle_root_bridge_insertion(handle);
692 
693 		break;
694 
695 	case ACPI_NOTIFY_DEVICE_CHECK:
696 		/* device check */
697 		printk(KERN_DEBUG "%s: Device check notify on %s\n", __func__,
698 				 (char *)buffer.pointer);
699 		if (!root)
700 			handle_root_bridge_insertion(handle);
701 		break;
702 
703 	case ACPI_NOTIFY_EJECT_REQUEST:
704 		/* request device eject */
705 		printk(KERN_DEBUG "%s: Device eject notify on %s\n", __func__,
706 				 (char *)buffer.pointer);
707 		if (root)
708 			handle_root_bridge_removal(root->device);
709 		break;
710 	default:
711 		printk(KERN_WARNING "notify_handler: unknown event type 0x%x for %s\n",
712 				 type, (char *)buffer.pointer);
713 		break;
714 	}
715 
716 	acpi_scan_lock_release();
717 	kfree(hp_work); /* allocated in handle_hotplug_event_bridge */
718 	kfree(buffer.pointer);
719 }
720 
721 static void handle_hotplug_event_root(acpi_handle handle, u32 type,
722 					void *context)
723 {
724 	alloc_acpi_hp_work(handle, type, context,
725 				_handle_hotplug_event_root);
726 }
727 
728 static acpi_status __init
729 find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
730 {
731 	acpi_status status;
732 	char objname[64];
733 	struct acpi_buffer buffer = { .length = sizeof(objname),
734 				      .pointer = objname };
735 	int *count = (int *)context;
736 
737 	if (!acpi_is_root_bridge(handle))
738 		return AE_OK;
739 
740 	(*count)++;
741 
742 	acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
743 
744 	status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
745 					handle_hotplug_event_root, NULL);
746 	if (ACPI_FAILURE(status))
747 		printk(KERN_DEBUG "acpi root: %s notify handler is not installed, exit status: %u\n",
748 				  objname, (unsigned int)status);
749 	else
750 		printk(KERN_DEBUG "acpi root: %s notify handler is installed\n",
751 				 objname);
752 
753 	return AE_OK;
754 }
755 
756 void __init acpi_pci_root_hp_init(void)
757 {
758 	int num = 0;
759 
760 	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
761 		ACPI_UINT32_MAX, find_root_bridges, NULL, &num, NULL);
762 
763 	printk(KERN_DEBUG "Found %d acpi root devices\n", num);
764 }
765