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pci_slot.c
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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 <[email protected]> for much guidance.
6  * Thanks to Kenji Kaneshige <[email protected]> for code
7  * review and fixes.
8  *
9  * Copyright (C) 2007-2008 Hewlett-Packard Development Company, L.P.
10  * Alex Chiang <[email protected]>
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/slab.h>
30 #include <linux/types.h>
31 #include <linux/pci.h>
32 #include <linux/acpi.h>
33 #include <acpi/acpi_bus.h>
34 #include <acpi/acpi_drivers.h>
35 #include <linux/dmi.h>
36 
37 static bool debug;
38 static int check_sta_before_sun;
39 
40 #define DRIVER_VERSION "0.1"
41 #define DRIVER_AUTHOR "Alex Chiang <[email protected]>"
42 #define DRIVER_DESC "ACPI PCI Slot Detection Driver"
45 MODULE_LICENSE("GPL");
46 MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
47 module_param(debug, bool, 0644);
48 
49 #define _COMPONENT ACPI_PCI_COMPONENT
50 ACPI_MODULE_NAME("pci_slot");
51 
52 #define MY_NAME "pci_slot"
53 #define err(format, arg...) printk(KERN_ERR "%s: " format , MY_NAME , ## arg)
54 #define info(format, arg...) printk(KERN_INFO "%s: " format , MY_NAME , ## arg)
55 #define dbg(format, arg...) \
56  do { \
57  if (debug) \
58  printk(KERN_DEBUG "%s: " format, \
59  MY_NAME , ## arg); \
60  } while (0)
61 
62 #define SLOT_NAME_SIZE 21 /* Inspired by #define in acpiphp.h */
63 
64 struct acpi_pci_slot {
65  acpi_handle root_handle; /* handle of the root bridge */
66  struct pci_slot *pci_slot; /* corresponding pci_slot */
67  struct list_head list; /* node in the list of slots */
68 };
69 
70 static int acpi_pci_slot_add(struct acpi_pci_root *root);
71 static void acpi_pci_slot_remove(struct acpi_pci_root *root);
72 
73 static LIST_HEAD(slot_list);
74 static DEFINE_MUTEX(slot_list_lock);
75 static struct acpi_pci_driver acpi_pci_slot_driver = {
76  .add = acpi_pci_slot_add,
77  .remove = acpi_pci_slot_remove,
78 };
79 
80 static int
81 check_slot(acpi_handle handle, unsigned long long *sun)
82 {
83  int device = -1;
84  unsigned long long adr, sta;
87 
88  acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
89  dbg("Checking slot on path: %s\n", (char *)buffer.pointer);
90 
91  if (check_sta_before_sun) {
92  /* If SxFy doesn't have _STA, we just assume it's there */
93  status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
94  if (ACPI_SUCCESS(status) && !(sta & ACPI_STA_DEVICE_PRESENT))
95  goto out;
96  }
97 
98  status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
99  if (ACPI_FAILURE(status)) {
100  dbg("_ADR returned %d on %s\n", status, (char *)buffer.pointer);
101  goto out;
102  }
103 
104  /* No _SUN == not a slot == bail */
105  status = acpi_evaluate_integer(handle, "_SUN", NULL, sun);
106  if (ACPI_FAILURE(status)) {
107  dbg("_SUN returned %d on %s\n", status, (char *)buffer.pointer);
108  goto out;
109  }
110 
111  device = (adr >> 16) & 0xffff;
112 out:
113  kfree(buffer.pointer);
114  return device;
115 }
116 
118  acpi_walk_callback user_function; /* only for walk_p2p_bridge */
119  struct pci_bus *pci_bus;
121 };
122 
123 /*
124  * register_slot
125  *
126  * Called once for each SxFy object in the namespace. Don't worry about
127  * calling pci_create_slot multiple times for the same pci_bus:device,
128  * since each subsequent call simply bumps the refcount on the pci_slot.
129  *
130  * The number of calls to pci_destroy_slot from unregister_slot is
131  * symmetrical.
132  */
133 static acpi_status
134 register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
135 {
136  int device;
137  unsigned long long sun;
138  char name[SLOT_NAME_SIZE];
139  struct acpi_pci_slot *slot;
140  struct pci_slot *pci_slot;
141  struct callback_args *parent_context = context;
142  struct pci_bus *pci_bus = parent_context->pci_bus;
143 
144  device = check_slot(handle, &sun);
145  if (device < 0)
146  return AE_OK;
147 
148  slot = kmalloc(sizeof(*slot), GFP_KERNEL);
149  if (!slot) {
150  err("%s: cannot allocate memory\n", __func__);
151  return AE_OK;
152  }
153 
154  snprintf(name, sizeof(name), "%llu", sun);
155  pci_slot = pci_create_slot(pci_bus, device, name, NULL);
156  if (IS_ERR(pci_slot)) {
157  err("pci_create_slot returned %ld\n", PTR_ERR(pci_slot));
158  kfree(slot);
159  return AE_OK;
160  }
161 
162  slot->root_handle = parent_context->root_handle;
163  slot->pci_slot = pci_slot;
164  INIT_LIST_HEAD(&slot->list);
165  mutex_lock(&slot_list_lock);
166  list_add(&slot->list, &slot_list);
167  mutex_unlock(&slot_list_lock);
168 
169  get_device(&pci_bus->dev);
170 
171  dbg("pci_slot: %p, pci_bus: %x, device: %d, name: %s\n",
172  pci_slot, pci_bus->number, device, name);
173 
174  return AE_OK;
175 }
176 
177 /*
178  * walk_p2p_bridge - discover and walk p2p bridges
179  * @handle: points to an acpi_pci_root
180  * @context: p2p_bridge_context pointer
181  *
182  * Note that when we call ourselves recursively, we pass a different
183  * value of pci_bus in the child_context.
184  */
185 static acpi_status
186 walk_p2p_bridge(acpi_handle handle, u32 lvl, void *context, void **rv)
187 {
188  int device, function;
189  unsigned long long adr;
191  acpi_handle dummy_handle;
192  acpi_walk_callback user_function;
193 
194  struct pci_dev *dev;
195  struct pci_bus *pci_bus;
196  struct callback_args child_context;
197  struct callback_args *parent_context = context;
198 
199  pci_bus = parent_context->pci_bus;
200  user_function = parent_context->user_function;
201 
202  status = acpi_get_handle(handle, "_ADR", &dummy_handle);
203  if (ACPI_FAILURE(status))
204  return AE_OK;
205 
206  status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
207  if (ACPI_FAILURE(status))
208  return AE_OK;
209 
210  device = (adr >> 16) & 0xffff;
211  function = adr & 0xffff;
212 
213  dev = pci_get_slot(pci_bus, PCI_DEVFN(device, function));
214  if (!dev || !dev->subordinate)
215  goto out;
216 
217  child_context.pci_bus = dev->subordinate;
218  child_context.user_function = user_function;
219  child_context.root_handle = parent_context->root_handle;
220 
221  dbg("p2p bridge walk, pci_bus = %x\n", dev->subordinate->number);
222  status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
223  user_function, NULL, &child_context, NULL);
224  if (ACPI_FAILURE(status))
225  goto out;
226 
227  status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
228  walk_p2p_bridge, NULL, &child_context, NULL);
229 out:
230  pci_dev_put(dev);
231  return AE_OK;
232 }
233 
234 /*
235  * walk_root_bridge - generic root bridge walker
236  * @root: poiner of an acpi_pci_root
237  * @user_function: user callback for slot objects
238  *
239  * Call user_function for all objects underneath this root bridge.
240  * Walk p2p bridges underneath us and call user_function on those too.
241  */
242 static int
243 walk_root_bridge(struct acpi_pci_root *root, acpi_walk_callback user_function)
244 {
246  acpi_handle handle = root->device->handle;
247  struct pci_bus *pci_bus = root->bus;
248  struct callback_args context;
249 
250  context.pci_bus = pci_bus;
251  context.user_function = user_function;
252  context.root_handle = handle;
253 
254  dbg("root bridge walk, pci_bus = %x\n", pci_bus->number);
255  status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
256  user_function, NULL, &context, NULL);
257  if (ACPI_FAILURE(status))
258  return status;
259 
260  status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
261  walk_p2p_bridge, NULL, &context, NULL);
262  if (ACPI_FAILURE(status))
263  err("%s: walk_p2p_bridge failure - %d\n", __func__, status);
264 
265  return status;
266 }
267 
268 /*
269  * acpi_pci_slot_add
270  * @handle: points to an acpi_pci_root
271  */
272 static int
273 acpi_pci_slot_add(struct acpi_pci_root *root)
274 {
276 
277  status = walk_root_bridge(root, register_slot);
278  if (ACPI_FAILURE(status))
279  err("%s: register_slot failure - %d\n", __func__, status);
280 
281  return status;
282 }
283 
284 /*
285  * acpi_pci_slot_remove
286  * @handle: points to an acpi_pci_root
287  */
288 static void
289 acpi_pci_slot_remove(struct acpi_pci_root *root)
290 {
291  struct acpi_pci_slot *slot, *tmp;
292  struct pci_bus *pbus;
293  acpi_handle handle = root->device->handle;
294 
295  mutex_lock(&slot_list_lock);
296  list_for_each_entry_safe(slot, tmp, &slot_list, list) {
297  if (slot->root_handle == handle) {
298  list_del(&slot->list);
299  pbus = slot->pci_slot->bus;
300  pci_destroy_slot(slot->pci_slot);
301  put_device(&pbus->dev);
302  kfree(slot);
303  }
304  }
305  mutex_unlock(&slot_list_lock);
306 }
307 
308 static int do_sta_before_sun(const struct dmi_system_id *d)
309 {
310  info("%s detected: will evaluate _STA before calling _SUN\n", d->ident);
311  check_sta_before_sun = 1;
312  return 0;
313 }
314 
315 static struct dmi_system_id acpi_pci_slot_dmi_table[] __initdata = {
316  /*
317  * Fujitsu Primequest machines will return 1023 to indicate an
318  * error if the _SUN method is evaluated on SxFy objects that
319  * are not present (as indicated by _STA), so for those machines,
320  * we want to check _STA before evaluating _SUN.
321  */
322  {
323  .callback = do_sta_before_sun,
324  .ident = "Fujitsu PRIMEQUEST",
325  .matches = {
326  DMI_MATCH(DMI_BIOS_VENDOR, "FUJITSU LIMITED"),
327  DMI_MATCH(DMI_BIOS_VERSION, "PRIMEQUEST"),
328  },
329  },
330  {}
331 };
332 
333 static int __init
334 acpi_pci_slot_init(void)
335 {
336  dmi_check_system(acpi_pci_slot_dmi_table);
337  acpi_pci_register_driver(&acpi_pci_slot_driver);
338  return 0;
339 }
340 
341 static void __exit
342 acpi_pci_slot_exit(void)
343 {
344  acpi_pci_unregister_driver(&acpi_pci_slot_driver);
345 }
346 
347 module_init(acpi_pci_slot_init);
348 module_exit(acpi_pci_slot_exit);