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/dmar.h>
37#include <linux/acpi.h>
38#include <linux/slab.h>
39#include <linux/dmi.h>
40#include <acpi/apei.h>	/* for acpi_hest_init() */
41
42#include "internal.h"
43
44#define _COMPONENT		ACPI_PCI_COMPONENT
45ACPI_MODULE_NAME("pci_root");
46#define ACPI_PCI_ROOT_CLASS		"pci_bridge"
47#define ACPI_PCI_ROOT_DEVICE_NAME	"PCI Root Bridge"
48static int acpi_pci_root_add(struct acpi_device *device,
49			     const struct acpi_device_id *not_used);
50static void acpi_pci_root_remove(struct acpi_device *device);
51
52static int acpi_pci_root_scan_dependent(struct acpi_device *adev)
53{
54	acpiphp_check_host_bridge(adev);
55	return 0;
56}
57
58#define ACPI_PCIE_REQ_SUPPORT (OSC_PCI_EXT_CONFIG_SUPPORT \
59				| OSC_PCI_ASPM_SUPPORT \
60				| OSC_PCI_CLOCK_PM_SUPPORT \
61				| OSC_PCI_MSI_SUPPORT)
62
63static const struct acpi_device_id root_device_ids[] = {
64	{"PNP0A03", 0},
65	{"", 0},
66};
67
68static struct acpi_scan_handler pci_root_handler = {
69	.ids = root_device_ids,
70	.attach = acpi_pci_root_add,
71	.detach = acpi_pci_root_remove,
72	.hotplug = {
73		.enabled = true,
74		.scan_dependent = acpi_pci_root_scan_dependent,
75	},
76};
77
78static DEFINE_MUTEX(osc_lock);
79
80/**
81 * acpi_is_root_bridge - determine whether an ACPI CA node is a PCI root bridge
82 * @handle - the ACPI CA node in question.
83 *
84 * Note: we could make this API take a struct acpi_device * instead, but
85 * for now, it's more convenient to operate on an acpi_handle.
86 */
87int acpi_is_root_bridge(acpi_handle handle)
88{
89	int ret;
90	struct acpi_device *device;
91
92	ret = acpi_bus_get_device(handle, &device);
93	if (ret)
94		return 0;
95
96	ret = acpi_match_device_ids(device, root_device_ids);
97	if (ret)
98		return 0;
99	else
100		return 1;
101}
102EXPORT_SYMBOL_GPL(acpi_is_root_bridge);
103
104static acpi_status
105get_root_bridge_busnr_callback(struct acpi_resource *resource, void *data)
106{
107	struct resource *res = data;
108	struct acpi_resource_address64 address;
109	acpi_status status;
110
111	status = acpi_resource_to_address64(resource, &address);
112	if (ACPI_FAILURE(status))
113		return AE_OK;
114
115	if ((address.address.address_length > 0) &&
116	    (address.resource_type == ACPI_BUS_NUMBER_RANGE)) {
117		res->start = address.address.minimum;
118		res->end = address.address.minimum + address.address.address_length - 1;
119	}
120
121	return AE_OK;
122}
123
124static acpi_status try_get_root_bridge_busnr(acpi_handle handle,
125					     struct resource *res)
126{
127	acpi_status status;
128
129	res->start = -1;
130	status =
131	    acpi_walk_resources(handle, METHOD_NAME__CRS,
132				get_root_bridge_busnr_callback, res);
133	if (ACPI_FAILURE(status))
134		return status;
135	if (res->start == -1)
136		return AE_ERROR;
137	return AE_OK;
138}
139
140struct pci_osc_bit_struct {
141	u32 bit;
142	char *desc;
143};
144
145static struct pci_osc_bit_struct pci_osc_support_bit[] = {
146	{ OSC_PCI_EXT_CONFIG_SUPPORT, "ExtendedConfig" },
147	{ OSC_PCI_ASPM_SUPPORT, "ASPM" },
148	{ OSC_PCI_CLOCK_PM_SUPPORT, "ClockPM" },
149	{ OSC_PCI_SEGMENT_GROUPS_SUPPORT, "Segments" },
150	{ OSC_PCI_MSI_SUPPORT, "MSI" },
151};
152
153static struct pci_osc_bit_struct pci_osc_control_bit[] = {
154	{ OSC_PCI_EXPRESS_NATIVE_HP_CONTROL, "PCIeHotplug" },
155	{ OSC_PCI_SHPC_NATIVE_HP_CONTROL, "SHPCHotplug" },
156	{ OSC_PCI_EXPRESS_PME_CONTROL, "PME" },
157	{ OSC_PCI_EXPRESS_AER_CONTROL, "AER" },
158	{ OSC_PCI_EXPRESS_CAPABILITY_CONTROL, "PCIeCapability" },
159};
160
161static void decode_osc_bits(struct acpi_pci_root *root, char *msg, u32 word,
162			    struct pci_osc_bit_struct *table, int size)
163{
164	char buf[80];
165	int i, len = 0;
166	struct pci_osc_bit_struct *entry;
167
168	buf[0] = '\0';
169	for (i = 0, entry = table; i < size; i++, entry++)
170		if (word & entry->bit)
171			len += snprintf(buf + len, sizeof(buf) - len, "%s%s",
172					len ? " " : "", entry->desc);
173
174	dev_info(&root->device->dev, "_OSC: %s [%s]\n", msg, buf);
175}
176
177static void decode_osc_support(struct acpi_pci_root *root, char *msg, u32 word)
178{
179	decode_osc_bits(root, msg, word, pci_osc_support_bit,
180			ARRAY_SIZE(pci_osc_support_bit));
181}
182
183static void decode_osc_control(struct acpi_pci_root *root, char *msg, u32 word)
184{
185	decode_osc_bits(root, msg, word, pci_osc_control_bit,
186			ARRAY_SIZE(pci_osc_control_bit));
187}
188
189static u8 pci_osc_uuid_str[] = "33DB4D5B-1FF7-401C-9657-7441C03DD766";
190
191static acpi_status acpi_pci_run_osc(acpi_handle handle,
192				    const u32 *capbuf, u32 *retval)
193{
194	struct acpi_osc_context context = {
195		.uuid_str = pci_osc_uuid_str,
196		.rev = 1,
197		.cap.length = 12,
198		.cap.pointer = (void *)capbuf,
199	};
200	acpi_status status;
201
202	status = acpi_run_osc(handle, &context);
203	if (ACPI_SUCCESS(status)) {
204		*retval = *((u32 *)(context.ret.pointer + 8));
205		kfree(context.ret.pointer);
206	}
207	return status;
208}
209
210static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root,
211					u32 support,
212					u32 *control)
213{
214	acpi_status status;
215	u32 result, capbuf[3];
216
217	support &= OSC_PCI_SUPPORT_MASKS;
218	support |= root->osc_support_set;
219
220	capbuf[OSC_QUERY_DWORD] = OSC_QUERY_ENABLE;
221	capbuf[OSC_SUPPORT_DWORD] = support;
222	if (control) {
223		*control &= OSC_PCI_CONTROL_MASKS;
224		capbuf[OSC_CONTROL_DWORD] = *control | root->osc_control_set;
225	} else {
226		/* Run _OSC query only with existing controls. */
227		capbuf[OSC_CONTROL_DWORD] = root->osc_control_set;
228	}
229
230	status = acpi_pci_run_osc(root->device->handle, capbuf, &result);
231	if (ACPI_SUCCESS(status)) {
232		root->osc_support_set = support;
233		if (control)
234			*control = result;
235	}
236	return status;
237}
238
239static acpi_status acpi_pci_osc_support(struct acpi_pci_root *root, u32 flags)
240{
241	acpi_status status;
242
243	mutex_lock(&osc_lock);
244	status = acpi_pci_query_osc(root, flags, NULL);
245	mutex_unlock(&osc_lock);
246	return status;
247}
248
249struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)
250{
251	struct acpi_pci_root *root;
252	struct acpi_device *device;
253
254	if (acpi_bus_get_device(handle, &device) ||
255	    acpi_match_device_ids(device, root_device_ids))
256		return NULL;
257
258	root = acpi_driver_data(device);
259
260	return root;
261}
262EXPORT_SYMBOL_GPL(acpi_pci_find_root);
263
264struct acpi_handle_node {
265	struct list_head node;
266	acpi_handle handle;
267};
268
269/**
270 * acpi_get_pci_dev - convert ACPI CA handle to struct pci_dev
271 * @handle: the handle in question
272 *
273 * Given an ACPI CA handle, the desired PCI device is located in the
274 * list of PCI devices.
275 *
276 * If the device is found, its reference count is increased and this
277 * function returns a pointer to its data structure.  The caller must
278 * decrement the reference count by calling pci_dev_put().
279 * If no device is found, %NULL is returned.
280 */
281struct pci_dev *acpi_get_pci_dev(acpi_handle handle)
282{
283	int dev, fn;
284	unsigned long long adr;
285	acpi_status status;
286	acpi_handle phandle;
287	struct pci_bus *pbus;
288	struct pci_dev *pdev = NULL;
289	struct acpi_handle_node *node, *tmp;
290	struct acpi_pci_root *root;
291	LIST_HEAD(device_list);
292
293	/*
294	 * Walk up the ACPI CA namespace until we reach a PCI root bridge.
295	 */
296	phandle = handle;
297	while (!acpi_is_root_bridge(phandle)) {
298		node = kzalloc(sizeof(struct acpi_handle_node), GFP_KERNEL);
299		if (!node)
300			goto out;
301
302		INIT_LIST_HEAD(&node->node);
303		node->handle = phandle;
304		list_add(&node->node, &device_list);
305
306		status = acpi_get_parent(phandle, &phandle);
307		if (ACPI_FAILURE(status))
308			goto out;
309	}
310
311	root = acpi_pci_find_root(phandle);
312	if (!root)
313		goto out;
314
315	pbus = root->bus;
316
317	/*
318	 * Now, walk back down the PCI device tree until we return to our
319	 * original handle. Assumes that everything between the PCI root
320	 * bridge and the device we're looking for must be a P2P bridge.
321	 */
322	list_for_each_entry(node, &device_list, node) {
323		acpi_handle hnd = node->handle;
324		status = acpi_evaluate_integer(hnd, "_ADR", NULL, &adr);
325		if (ACPI_FAILURE(status))
326			goto out;
327		dev = (adr >> 16) & 0xffff;
328		fn  = adr & 0xffff;
329
330		pdev = pci_get_slot(pbus, PCI_DEVFN(dev, fn));
331		if (!pdev || hnd == handle)
332			break;
333
334		pbus = pdev->subordinate;
335		pci_dev_put(pdev);
336
337		/*
338		 * This function may be called for a non-PCI device that has a
339		 * PCI parent (eg. a disk under a PCI SATA controller).  In that
340		 * case pdev->subordinate will be NULL for the parent.
341		 */
342		if (!pbus) {
343			dev_dbg(&pdev->dev, "Not a PCI-to-PCI bridge\n");
344			pdev = NULL;
345			break;
346		}
347	}
348out:
349	list_for_each_entry_safe(node, tmp, &device_list, node)
350		kfree(node);
351
352	return pdev;
353}
354EXPORT_SYMBOL_GPL(acpi_get_pci_dev);
355
356/**
357 * acpi_pci_osc_control_set - Request control of PCI root _OSC features.
358 * @handle: ACPI handle of a PCI root bridge (or PCIe Root Complex).
359 * @mask: Mask of _OSC bits to request control of, place to store control mask.
360 * @req: Mask of _OSC bits the control of is essential to the caller.
361 *
362 * Run _OSC query for @mask and if that is successful, compare the returned
363 * mask of control bits with @req.  If all of the @req bits are set in the
364 * returned mask, run _OSC request for it.
365 *
366 * The variable at the @mask address may be modified regardless of whether or
367 * not the function returns success.  On success it will contain the mask of
368 * _OSC bits the BIOS has granted control of, but its contents are meaningless
369 * on failure.
370 **/
371acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 req)
372{
373	struct acpi_pci_root *root;
374	acpi_status status = AE_OK;
375	u32 ctrl, capbuf[3];
376
377	if (!mask)
378		return AE_BAD_PARAMETER;
379
380	ctrl = *mask & OSC_PCI_CONTROL_MASKS;
381	if ((ctrl & req) != req)
382		return AE_TYPE;
383
384	root = acpi_pci_find_root(handle);
385	if (!root)
386		return AE_NOT_EXIST;
387
388	mutex_lock(&osc_lock);
389
390	*mask = ctrl | root->osc_control_set;
391	/* No need to evaluate _OSC if the control was already granted. */
392	if ((root->osc_control_set & ctrl) == ctrl)
393		goto out;
394
395	/* Need to check the available controls bits before requesting them. */
396	while (*mask) {
397		status = acpi_pci_query_osc(root, root->osc_support_set, mask);
398		if (ACPI_FAILURE(status))
399			goto out;
400		if (ctrl == *mask)
401			break;
402		decode_osc_control(root, "platform does not support",
403				   ctrl & ~(*mask));
404		ctrl = *mask;
405	}
406
407	if ((ctrl & req) != req) {
408		decode_osc_control(root, "not requesting control; platform does not support",
409				   req & ~(ctrl));
410		status = AE_SUPPORT;
411		goto out;
412	}
413
414	capbuf[OSC_QUERY_DWORD] = 0;
415	capbuf[OSC_SUPPORT_DWORD] = root->osc_support_set;
416	capbuf[OSC_CONTROL_DWORD] = ctrl;
417	status = acpi_pci_run_osc(handle, capbuf, mask);
418	if (ACPI_SUCCESS(status))
419		root->osc_control_set = *mask;
420out:
421	mutex_unlock(&osc_lock);
422	return status;
423}
424EXPORT_SYMBOL(acpi_pci_osc_control_set);
425
426static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
427{
428	u32 support, control, requested;
429	acpi_status status;
430	struct acpi_device *device = root->device;
431	acpi_handle handle = device->handle;
432
433	/*
434	 * Apple always return failure on _OSC calls when _OSI("Darwin") has
435	 * been called successfully. We know the feature set supported by the
436	 * platform, so avoid calling _OSC at all
437	 */
438
439	if (dmi_match(DMI_SYS_VENDOR, "Apple Inc.")) {
440		root->osc_control_set = ~OSC_PCI_EXPRESS_PME_CONTROL;
441		decode_osc_control(root, "OS assumes control of",
442				   root->osc_control_set);
443		return;
444	}
445
446	/*
447	 * All supported architectures that use ACPI have support for
448	 * PCI domains, so we indicate this in _OSC support capabilities.
449	 */
450	support = OSC_PCI_SEGMENT_GROUPS_SUPPORT;
451	if (pci_ext_cfg_avail())
452		support |= OSC_PCI_EXT_CONFIG_SUPPORT;
453	if (pcie_aspm_support_enabled())
454		support |= OSC_PCI_ASPM_SUPPORT | OSC_PCI_CLOCK_PM_SUPPORT;
455	if (pci_msi_enabled())
456		support |= OSC_PCI_MSI_SUPPORT;
457
458	decode_osc_support(root, "OS supports", support);
459	status = acpi_pci_osc_support(root, support);
460	if (ACPI_FAILURE(status)) {
461		dev_info(&device->dev, "_OSC failed (%s); disabling ASPM\n",
462			 acpi_format_exception(status));
463		*no_aspm = 1;
464		return;
465	}
466
467	if (pcie_ports_disabled) {
468		dev_info(&device->dev, "PCIe port services disabled; not requesting _OSC control\n");
469		return;
470	}
471
472	if ((support & ACPI_PCIE_REQ_SUPPORT) != ACPI_PCIE_REQ_SUPPORT) {
473		decode_osc_support(root, "not requesting OS control; OS requires",
474				   ACPI_PCIE_REQ_SUPPORT);
475		return;
476	}
477
478	control = OSC_PCI_EXPRESS_CAPABILITY_CONTROL
479		| OSC_PCI_EXPRESS_NATIVE_HP_CONTROL
480		| OSC_PCI_EXPRESS_PME_CONTROL;
481
482	if (pci_aer_available()) {
483		if (aer_acpi_firmware_first())
484			dev_info(&device->dev,
485				 "PCIe AER handled by firmware\n");
486		else
487			control |= OSC_PCI_EXPRESS_AER_CONTROL;
488	}
489
490	requested = control;
491	status = acpi_pci_osc_control_set(handle, &control,
492					  OSC_PCI_EXPRESS_CAPABILITY_CONTROL);
493	if (ACPI_SUCCESS(status)) {
494		decode_osc_control(root, "OS now controls", control);
495		if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {
496			/*
497			 * We have ASPM control, but the FADT indicates that
498			 * it's unsupported. Leave existing configuration
499			 * intact and prevent the OS from touching it.
500			 */
501			dev_info(&device->dev, "FADT indicates ASPM is unsupported, using BIOS configuration\n");
502			*no_aspm = 1;
503		}
504	} else {
505		decode_osc_control(root, "OS requested", requested);
506		decode_osc_control(root, "platform willing to grant", control);
507		dev_info(&device->dev, "_OSC failed (%s); disabling ASPM\n",
508			acpi_format_exception(status));
509
510		/*
511		 * We want to disable ASPM here, but aspm_disabled
512		 * needs to remain in its state from boot so that we
513		 * properly handle PCIe 1.1 devices.  So we set this
514		 * flag here, to defer the action until after the ACPI
515		 * root scan.
516		 */
517		*no_aspm = 1;
518	}
519}
520
521static int acpi_pci_root_add(struct acpi_device *device,
522			     const struct acpi_device_id *not_used)
523{
524	unsigned long long segment, bus;
525	acpi_status status;
526	int result;
527	struct acpi_pci_root *root;
528	acpi_handle handle = device->handle;
529	int no_aspm = 0;
530	bool hotadd = system_state != SYSTEM_BOOTING;
531
532	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
533	if (!root)
534		return -ENOMEM;
535
536	segment = 0;
537	status = acpi_evaluate_integer(handle, METHOD_NAME__SEG, NULL,
538				       &segment);
539	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
540		dev_err(&device->dev,  "can't evaluate _SEG\n");
541		result = -ENODEV;
542		goto end;
543	}
544
545	/* Check _CRS first, then _BBN.  If no _BBN, default to zero. */
546	root->secondary.flags = IORESOURCE_BUS;
547	status = try_get_root_bridge_busnr(handle, &root->secondary);
548	if (ACPI_FAILURE(status)) {
549		/*
550		 * We need both the start and end of the downstream bus range
551		 * to interpret _CBA (MMCONFIG base address), so it really is
552		 * supposed to be in _CRS.  If we don't find it there, all we
553		 * can do is assume [_BBN-0xFF] or [0-0xFF].
554		 */
555		root->secondary.end = 0xFF;
556		dev_warn(&device->dev,
557			 FW_BUG "no secondary bus range in _CRS\n");
558		status = acpi_evaluate_integer(handle, METHOD_NAME__BBN,
559					       NULL, &bus);
560		if (ACPI_SUCCESS(status))
561			root->secondary.start = bus;
562		else if (status == AE_NOT_FOUND)
563			root->secondary.start = 0;
564		else {
565			dev_err(&device->dev, "can't evaluate _BBN\n");
566			result = -ENODEV;
567			goto end;
568		}
569	}
570
571	root->device = device;
572	root->segment = segment & 0xFFFF;
573	strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME);
574	strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
575	device->driver_data = root;
576
577	if (hotadd && dmar_device_add(handle)) {
578		result = -ENXIO;
579		goto end;
580	}
581
582	pr_info(PREFIX "%s [%s] (domain %04x %pR)\n",
583	       acpi_device_name(device), acpi_device_bid(device),
584	       root->segment, &root->secondary);
585
586	root->mcfg_addr = acpi_pci_root_get_mcfg_addr(handle);
587
588	negotiate_os_control(root, &no_aspm);
589
590	/*
591	 * TBD: Need PCI interface for enumeration/configuration of roots.
592	 */
593
594	/*
595	 * Scan the Root Bridge
596	 * --------------------
597	 * Must do this prior to any attempt to bind the root device, as the
598	 * PCI namespace does not get created until this call is made (and
599	 * thus the root bridge's pci_dev does not exist).
600	 */
601	root->bus = pci_acpi_scan_root(root);
602	if (!root->bus) {
603		dev_err(&device->dev,
604			"Bus %04x:%02x not present in PCI namespace\n",
605			root->segment, (unsigned int)root->secondary.start);
606		device->driver_data = NULL;
607		result = -ENODEV;
608		goto remove_dmar;
609	}
610
611	if (no_aspm)
612		pcie_no_aspm();
613
614	pci_acpi_add_bus_pm_notifier(device);
615	if (device->wakeup.flags.run_wake)
616		device_set_run_wake(root->bus->bridge, true);
617
618	if (hotadd) {
619		pcibios_resource_survey_bus(root->bus);
620		pci_assign_unassigned_root_bus_resources(root->bus);
621		acpi_ioapic_add(root);
622	}
623
624	pci_lock_rescan_remove();
625	pci_bus_add_devices(root->bus);
626	pci_unlock_rescan_remove();
627	return 1;
628
629remove_dmar:
630	if (hotadd)
631		dmar_device_remove(handle);
632end:
633	kfree(root);
634	return result;
635}
636
637static void acpi_pci_root_remove(struct acpi_device *device)
638{
639	struct acpi_pci_root *root = acpi_driver_data(device);
640
641	pci_lock_rescan_remove();
642
643	pci_stop_root_bus(root->bus);
644
645	WARN_ON(acpi_ioapic_remove(root));
646
647	device_set_run_wake(root->bus->bridge, false);
648	pci_acpi_remove_bus_pm_notifier(device);
649
650	pci_remove_root_bus(root->bus);
651
652	dmar_device_remove(device->handle);
653
654	pci_unlock_rescan_remove();
655
656	kfree(root);
657}
658
659void __init acpi_pci_root_init(void)
660{
661	acpi_hest_init();
662	if (acpi_pci_disabled)
663		return;
664
665	pci_acpi_crs_quirks();
666	acpi_scan_add_handler_with_hotplug(&pci_root_handler, "pci_root");
667}
668