xref: /openbmc/linux/drivers/acpi/pci_slot.c (revision 9ac8d3fb)
1 /*
2  *  pci_slot.c - ACPI PCI Slot Driver
3  *
4  *  The code here is heavily leveraged from the acpiphp module.
5  *  Thanks to Matthew Wilcox <matthew@wil.cx> for much guidance.
6  *  Thanks to Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> for code
7  *  review and fixes.
8  *
9  *  Copyright (C) 2007-2008 Hewlett-Packard Development Company, L.P.
10  *  	Alex Chiang <achiang@hp.com>
11  *
12  *  This program is free software; you can redistribute it and/or modify it
13  *  under the terms and conditions of the GNU General Public License,
14  *  version 2, as published by the Free Software Foundation.
15  *
16  *  This program is distributed in the hope that it will be useful, but
17  *  WITHOUT ANY WARRANTY; without even the implied warranty of
18  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
19  *  General Public License for more details.
20  *
21  *  You should have received a copy of the GNU General Public License along
22  *  with this program; if not, write to the Free Software Foundation, Inc.,
23  *  51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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/pci.h>
31 #include <linux/acpi.h>
32 #include <acpi/acpi_bus.h>
33 #include <acpi/acpi_drivers.h>
34 
35 static int debug;
36 static int check_sta_before_sun;
37 
38 #define DRIVER_VERSION 	"0.1"
39 #define DRIVER_AUTHOR	"Alex Chiang <achiang@hp.com>"
40 #define DRIVER_DESC	"ACPI PCI Slot Detection Driver"
41 MODULE_AUTHOR(DRIVER_AUTHOR);
42 MODULE_DESCRIPTION(DRIVER_DESC);
43 MODULE_LICENSE("GPL");
44 MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
45 module_param(debug, bool, 0644);
46 
47 #define _COMPONENT		ACPI_PCI_COMPONENT
48 ACPI_MODULE_NAME("pci_slot");
49 
50 #define MY_NAME "pci_slot"
51 #define err(format, arg...) printk(KERN_ERR "%s: " format , MY_NAME , ## arg)
52 #define info(format, arg...) printk(KERN_INFO "%s: " format , MY_NAME , ## arg)
53 #define dbg(format, arg...)					\
54 	do {							\
55 		if (debug)					\
56 			printk(KERN_DEBUG "%s: " format,	\
57 				MY_NAME , ## arg);		\
58 	} while (0)
59 
60 #define SLOT_NAME_SIZE 20		/* Inspired by #define in acpiphp.h */
61 
62 struct acpi_pci_slot {
63 	acpi_handle root_handle;	/* handle of the root bridge */
64 	struct pci_slot *pci_slot;	/* corresponding pci_slot */
65 	struct list_head list;		/* node in the list of slots */
66 };
67 
68 static int acpi_pci_slot_add(acpi_handle handle);
69 static void acpi_pci_slot_remove(acpi_handle handle);
70 
71 static LIST_HEAD(slot_list);
72 static DEFINE_MUTEX(slot_list_lock);
73 static struct acpi_pci_driver acpi_pci_slot_driver = {
74 	.add = acpi_pci_slot_add,
75 	.remove = acpi_pci_slot_remove,
76 };
77 
78 static int
79 check_slot(acpi_handle handle, unsigned long long *sun)
80 {
81 	int device = -1;
82 	unsigned long long adr, sta;
83 	acpi_status status;
84 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
85 
86 	acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
87 	dbg("Checking slot on path: %s\n", (char *)buffer.pointer);
88 
89 	if (check_sta_before_sun) {
90 		/* If SxFy doesn't have _STA, we just assume it's there */
91 		status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
92 		if (ACPI_SUCCESS(status) && !(sta & ACPI_STA_DEVICE_PRESENT))
93 			goto out;
94 	}
95 
96 	status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
97 	if (ACPI_FAILURE(status)) {
98 		dbg("_ADR returned %d on %s\n", status, (char *)buffer.pointer);
99 		goto out;
100 	}
101 
102 	/* No _SUN == not a slot == bail */
103 	status = acpi_evaluate_integer(handle, "_SUN", NULL, sun);
104 	if (ACPI_FAILURE(status)) {
105 		dbg("_SUN returned %d on %s\n", status, (char *)buffer.pointer);
106 		goto out;
107 	}
108 
109 	device = (adr >> 16) & 0xffff;
110 out:
111 	kfree(buffer.pointer);
112 	return device;
113 }
114 
115 struct callback_args {
116 	acpi_walk_callback	user_function;	/* only for walk_p2p_bridge */
117 	struct pci_bus		*pci_bus;
118 	acpi_handle		root_handle;
119 };
120 
121 /*
122  * register_slot
123  *
124  * Called once for each SxFy object in the namespace. Don't worry about
125  * calling pci_create_slot multiple times for the same pci_bus:device,
126  * since each subsequent call simply bumps the refcount on the pci_slot.
127  *
128  * The number of calls to pci_destroy_slot from unregister_slot is
129  * symmetrical.
130  */
131 static acpi_status
132 register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
133 {
134 	int device;
135 	unsigned long long sun;
136 	char name[SLOT_NAME_SIZE];
137 	struct acpi_pci_slot *slot;
138 	struct pci_slot *pci_slot;
139 	struct callback_args *parent_context = context;
140 	struct pci_bus *pci_bus = parent_context->pci_bus;
141 
142 	device = check_slot(handle, &sun);
143 	if (device < 0)
144 		return AE_OK;
145 
146 	slot = kmalloc(sizeof(*slot), GFP_KERNEL);
147 	if (!slot) {
148 		err("%s: cannot allocate memory\n", __func__);
149 		return AE_OK;
150 	}
151 
152 	snprintf(name, sizeof(name), "%u", (u32)sun);
153 	pci_slot = pci_create_slot(pci_bus, device, name, NULL);
154 	if (IS_ERR(pci_slot)) {
155 		err("pci_create_slot returned %ld\n", PTR_ERR(pci_slot));
156 		kfree(slot);
157 		return AE_OK;
158 	}
159 
160 	slot->root_handle = parent_context->root_handle;
161 	slot->pci_slot = pci_slot;
162 	INIT_LIST_HEAD(&slot->list);
163 	mutex_lock(&slot_list_lock);
164 	list_add(&slot->list, &slot_list);
165 	mutex_unlock(&slot_list_lock);
166 
167 	dbg("pci_slot: %p, pci_bus: %x, device: %d, name: %s\n",
168 		pci_slot, pci_bus->number, device, name);
169 
170 	return AE_OK;
171 }
172 
173 /*
174  * walk_p2p_bridge - discover and walk p2p bridges
175  * @handle: points to an acpi_pci_root
176  * @context: p2p_bridge_context pointer
177  *
178  * Note that when we call ourselves recursively, we pass a different
179  * value of pci_bus in the child_context.
180  */
181 static acpi_status
182 walk_p2p_bridge(acpi_handle handle, u32 lvl, void *context, void **rv)
183 {
184 	int device, function;
185 	unsigned long long adr;
186 	acpi_status status;
187 	acpi_handle dummy_handle;
188 	acpi_walk_callback user_function;
189 
190 	struct pci_dev *dev;
191 	struct pci_bus *pci_bus;
192 	struct callback_args child_context;
193 	struct callback_args *parent_context = context;
194 
195 	pci_bus = parent_context->pci_bus;
196 	user_function = parent_context->user_function;
197 
198 	status = acpi_get_handle(handle, "_ADR", &dummy_handle);
199 	if (ACPI_FAILURE(status))
200 		return AE_OK;
201 
202 	status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
203 	if (ACPI_FAILURE(status))
204 		return AE_OK;
205 
206 	device = (adr >> 16) & 0xffff;
207 	function = adr & 0xffff;
208 
209 	dev = pci_get_slot(pci_bus, PCI_DEVFN(device, function));
210 	if (!dev || !dev->subordinate)
211 		goto out;
212 
213 	child_context.pci_bus = dev->subordinate;
214 	child_context.user_function = user_function;
215 	child_context.root_handle = parent_context->root_handle;
216 
217 	dbg("p2p bridge walk, pci_bus = %x\n", dev->subordinate->number);
218 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
219 				     user_function, &child_context, NULL);
220 	if (ACPI_FAILURE(status))
221 		goto out;
222 
223 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
224 				     walk_p2p_bridge, &child_context, NULL);
225 out:
226 	pci_dev_put(dev);
227 	return AE_OK;
228 }
229 
230 /*
231  * walk_root_bridge - generic root bridge walker
232  * @handle: points to an acpi_pci_root
233  * @user_function: user callback for slot objects
234  *
235  * Call user_function for all objects underneath this root bridge.
236  * Walk p2p bridges underneath us and call user_function on those too.
237  */
238 static int
239 walk_root_bridge(acpi_handle handle, acpi_walk_callback user_function)
240 {
241 	int seg, bus;
242 	unsigned long long tmp;
243 	acpi_status status;
244 	acpi_handle dummy_handle;
245 	struct pci_bus *pci_bus;
246 	struct callback_args context;
247 
248 	/* If the bridge doesn't have _STA, we assume it is always there */
249 	status = acpi_get_handle(handle, "_STA", &dummy_handle);
250 	if (ACPI_SUCCESS(status)) {
251 		status = acpi_evaluate_integer(handle, "_STA", NULL, &tmp);
252 		if (ACPI_FAILURE(status)) {
253 			info("%s: _STA evaluation failure\n", __func__);
254 			return 0;
255 		}
256 		if ((tmp & ACPI_STA_DEVICE_FUNCTIONING) == 0)
257 			/* don't register this object */
258 			return 0;
259 	}
260 
261 	status = acpi_evaluate_integer(handle, "_SEG", NULL, &tmp);
262 	seg = ACPI_SUCCESS(status) ? tmp : 0;
263 
264 	status = acpi_evaluate_integer(handle, "_BBN", NULL, &tmp);
265 	bus = ACPI_SUCCESS(status) ? tmp : 0;
266 
267 	pci_bus = pci_find_bus(seg, bus);
268 	if (!pci_bus)
269 		return 0;
270 
271 	context.pci_bus = pci_bus;
272 	context.user_function = user_function;
273 	context.root_handle = handle;
274 
275 	dbg("root bridge walk, pci_bus = %x\n", pci_bus->number);
276 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
277 				     user_function, &context, NULL);
278 	if (ACPI_FAILURE(status))
279 		return status;
280 
281 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
282 				     walk_p2p_bridge, &context, NULL);
283 	if (ACPI_FAILURE(status))
284 		err("%s: walk_p2p_bridge failure - %d\n", __func__, status);
285 
286 	return status;
287 }
288 
289 /*
290  * acpi_pci_slot_add
291  * @handle: points to an acpi_pci_root
292  */
293 static int
294 acpi_pci_slot_add(acpi_handle handle)
295 {
296 	acpi_status status;
297 
298 	status = walk_root_bridge(handle, register_slot);
299 	if (ACPI_FAILURE(status))
300 		err("%s: register_slot failure - %d\n", __func__, status);
301 
302 	return status;
303 }
304 
305 /*
306  * acpi_pci_slot_remove
307  * @handle: points to an acpi_pci_root
308  */
309 static void
310 acpi_pci_slot_remove(acpi_handle handle)
311 {
312 	struct acpi_pci_slot *slot, *tmp;
313 
314 	mutex_lock(&slot_list_lock);
315 	list_for_each_entry_safe(slot, tmp, &slot_list, list) {
316 		if (slot->root_handle == handle) {
317 			list_del(&slot->list);
318 			pci_destroy_slot(slot->pci_slot);
319 			kfree(slot);
320 		}
321 	}
322 	mutex_unlock(&slot_list_lock);
323 }
324 
325 static int do_sta_before_sun(const struct dmi_system_id *d)
326 {
327 	info("%s detected: will evaluate _STA before calling _SUN\n", d->ident);
328 	check_sta_before_sun = 1;
329 	return 0;
330 }
331 
332 static struct dmi_system_id acpi_pci_slot_dmi_table[] __initdata = {
333 	/*
334 	 * Fujitsu Primequest machines will return 1023 to indicate an
335 	 * error if the _SUN method is evaluated on SxFy objects that
336 	 * are not present (as indicated by _STA), so for those machines,
337 	 * we want to check _STA before evaluating _SUN.
338 	 */
339 	{
340 	 .callback = do_sta_before_sun,
341 	 .ident = "Fujitsu PRIMEQUEST",
342 	 .matches = {
343 		DMI_MATCH(DMI_BIOS_VENDOR, "FUJITSU LIMITED"),
344 		DMI_MATCH(DMI_BIOS_VERSION, "PRIMEQUEST"),
345 		},
346 	},
347 	{}
348 };
349 
350 static int __init
351 acpi_pci_slot_init(void)
352 {
353 	dmi_check_system(acpi_pci_slot_dmi_table);
354 	acpi_pci_register_driver(&acpi_pci_slot_driver);
355 	return 0;
356 }
357 
358 static void __exit
359 acpi_pci_slot_exit(void)
360 {
361 	acpi_pci_unregister_driver(&acpi_pci_slot_driver);
362 }
363 
364 module_init(acpi_pci_slot_init);
365 module_exit(acpi_pci_slot_exit);
366