1 /*
2 * Fake PCI Hot Plug Controller Driver
3 *
4 * Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
5 * Copyright (C) 2003 IBM Corp.
6 * Copyright (C) 2003 Rolf Eike Beer <eike-kernel@sf-tec.de>
7 *
8 * Based on ideas and code from:
9 * Vladimir Kondratiev <vladimir.kondratiev@intel.com>
10 * Rolf Eike Beer <eike-kernel@sf-tec.de>
11 *
12 * All rights reserved.
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation, version 2 of the License.
17 *
18 * Send feedback to <greg@kroah.com>
19 */
20
21 /*
22 *
23 * This driver will "emulate" removing PCI devices from the system. If
24 * the "power" file is written to with "" then the specified PCI device
25 * will be completely removed from the kernel.
26 *
27 * WARNING, this does NOT turn off the power to the PCI device. This is
28 * a "logical" removal, not a physical or electrical removal.
29 *
30 * Use this module at your own risk, you have been warned!
31 *
32 * Enabling PCI devices is left as an exercise for the reader...
33 *
34 */
35 #include <linux/kernel.h>
36 #include <linux/module.h>
37 #include <linux/pci.h>
38 #include <linux/pci_hotplug.h>
39 #include <linux/init.h>
40 #include <linux/string.h>
41 #include <linux/slab.h>
42 #include <linux/workqueue.h>
43 #include "../pci.h"
44
45 #if !defined(MODULE)
46 #define MY_NAME "fakephp"
47 #else
48 #define MY_NAME THIS_MODULE->name
49 #endif
50
51 #define dbg(format, arg...) \
52 do { \
53 if (debug) \
54 printk(KERN_DEBUG "%s: " format, \
55 MY_NAME , ## arg); \
56 } while (0)
57 #define err(format, arg...) printk(KERN_ERR "%s: " format, MY_NAME , ## arg)
58 #define info(format, arg...) printk(KERN_INFO "%s: " format, MY_NAME , ## arg)
59
60 #define DRIVER_AUTHOR "Greg Kroah-Hartman <greg@kroah.com>"
61 #define DRIVER_DESC "Fake PCI Hot Plug Controller Driver"
62
63 struct dummy_slot {
64 struct list_head node;
65 struct hotplug_slot *slot;
66 struct pci_dev *dev;
67 struct work_struct remove_work;
68 unsigned long removed;
69 };
70
71 static int debug;
72 static LIST_HEAD(slot_list);
73 static struct workqueue_struct *dummyphp_wq;
74
75 static void pci_rescan_worker(struct work_struct *work);
76 static DECLARE_WORK(pci_rescan_work, pci_rescan_worker);
77
78 static int enable_slot (struct hotplug_slot *slot);
79 static int disable_slot (struct hotplug_slot *slot);
80
81 static struct hotplug_slot_ops dummy_hotplug_slot_ops = {
82 .owner = THIS_MODULE,
83 .enable_slot = enable_slot,
84 .disable_slot = disable_slot,
85 };
86
87 static void dummy_release(struct hotplug_slot *slot)
88 {
89 struct dummy_slot *dslot = slot->private;
90
91 list_del(&dslot->node);
92 kfree(dslot->slot->info);
93 kfree(dslot->slot);
94 pci_dev_put(dslot->dev);
95 kfree(dslot);
96 }
97
98 static int add_slot(struct pci_dev *dev)
99 {
100 struct dummy_slot *dslot;
101 struct hotplug_slot *slot;
102 int retval = -ENOMEM;
103
104 slot = kzalloc(sizeof(struct hotplug_slot), GFP_KERNEL);
105 if (!slot)
106 goto error;
107
108 slot->info = kzalloc(sizeof(struct hotplug_slot_info), GFP_KERNEL);
109 if (!slot->info)
110 goto error_slot;
111
112 slot->info->power_status = 1;
113 slot->info->max_bus_speed = PCI_SPEED_UNKNOWN;
114 slot->info->cur_bus_speed = PCI_SPEED_UNKNOWN;
115
116 slot->name = &dev->dev.bus_id[0];
117 dbg("slot->name = %s\n", slot->name);
118
119 dslot = kzalloc(sizeof(struct dummy_slot), GFP_KERNEL);
120 if (!dslot)
121 goto error_info;
122
123 slot->ops = &dummy_hotplug_slot_ops;
124 slot->release = &dummy_release;
125 slot->private = dslot;
126
127 retval = pci_hp_register(slot);
128 if (retval) {
129 err("pci_hp_register failed with error %d\n", retval);
130 goto error_dslot;
131 }
132
133 dslot->slot = slot;
134 dslot->dev = pci_dev_get(dev);
135 list_add (&dslot->node, &slot_list);
136 return retval;
137
138 error_dslot:
139 kfree(dslot);
140 error_info:
141 kfree(slot->info);
142 error_slot:
143 kfree(slot);
144 error:
145 return retval;
146 }
147
148 static int __init pci_scan_buses(void)
149 {
150 struct pci_dev *dev = NULL;
151 int retval = 0;
152
153 while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
154 retval = add_slot(dev);
155 if (retval) {
156 pci_dev_put(dev);
157 break;
158 }
159 }
160
161 return retval;
162 }
163
164 static void remove_slot(struct dummy_slot *dslot)
165 {
166 int retval;
167
168 dbg("removing slot %s\n", dslot->slot->name);
169 retval = pci_hp_deregister(dslot->slot);
170 if (retval)
171 err("Problem unregistering a slot %s\n", dslot->slot->name);
172 }
173
174 /* called from the single-threaded workqueue handler to remove a slot */
175 static void remove_slot_worker(struct work_struct *work)
176 {
177 struct dummy_slot *dslot =
178 container_of(work, struct dummy_slot, remove_work);
179 remove_slot(dslot);
180 }
181
182 /**
183 * pci_rescan_slot - Rescan slot
184 * @temp: Device template. Should be set: bus and devfn.
185 *
186 * Tries hard not to re-enable already existing devices;
187 * also handles scanning of subfunctions.
188 */
189 static void pci_rescan_slot(struct pci_dev *temp)
190 {
191 struct pci_bus *bus = temp->bus;
192 struct pci_dev *dev;
193 int func;
194 int retval;
195 u8 hdr_type;
196
197 if (!pci_read_config_byte(temp, PCI_HEADER_TYPE, &hdr_type)) {
198 temp->hdr_type = hdr_type & 0x7f;
199 if ((dev = pci_get_slot(bus, temp->devfn)) != NULL)
200 pci_dev_put(dev);
201 else {
202 dev = pci_scan_single_device(bus, temp->devfn);
203 if (dev) {
204 dbg("New device on %s function %x:%x\n",
205 bus->name, temp->devfn >> 3,
206 temp->devfn & 7);
207 retval = pci_bus_add_device(dev);
208 if (retval)
209 dev_err(&dev->dev, "error adding "
210 "device, continuing.\n");
211 else
212 add_slot(dev);
213 }
214 }
215 /* multifunction device? */
216 if (!(hdr_type & 0x80))
217 return;
218
219 /* continue scanning for other functions */
220 for (func = 1, temp->devfn++; func < 8; func++, temp->devfn++) {
221 if (pci_read_config_byte(temp, PCI_HEADER_TYPE, &hdr_type))
222 continue;
223 temp->hdr_type = hdr_type & 0x7f;
224
225 if ((dev = pci_get_slot(bus, temp->devfn)) != NULL)
226 pci_dev_put(dev);
227 else {
228 dev = pci_scan_single_device(bus, temp->devfn);
229 if (dev) {
230 dbg("New device on %s function %x:%x\n",
231 bus->name, temp->devfn >> 3,
232 temp->devfn & 7);
233 retval = pci_bus_add_device(dev);
234 if (retval)
235 dev_err(&dev->dev, "error adding "
236 "device, continuing.\n");
237 else
238 add_slot(dev);
239 }
240 }
241 }
242 }
243 }
244
245
246 /**
247 * pci_rescan_bus - Rescan PCI bus
248 * @bus: the PCI bus to rescan
249 *
250 * Call pci_rescan_slot for each possible function of the bus.
251 */
252 static void pci_rescan_bus(const struct pci_bus *bus)
253 {
254 unsigned int devfn;
255 struct pci_dev *dev;
256 dev = alloc_pci_dev();
257 if (!dev)
258 return;
259
260 dev->bus = (struct pci_bus*)bus;
261 dev->sysdata = bus->sysdata;
262 for (devfn = 0; devfn < 0x100; devfn += 8) {
263 dev->devfn = devfn;
264 pci_rescan_slot(dev);
265 }
266 kfree(dev);
267 }
268
269 /* recursively scan all buses */
270 static void pci_rescan_buses(const struct list_head *list)
271 {
272 const struct list_head *l;
273 list_for_each(l,list) {
274 const struct pci_bus *b = pci_bus_b(l);
275 pci_rescan_bus(b);
276 pci_rescan_buses(&b->children);
277 }
278 }
279
280 /* initiate rescan of all pci buses */
281 static inline void pci_rescan(void) {
282 pci_rescan_buses(&pci_root_buses);
283 }
284
285 /* called from the single-threaded workqueue handler to rescan all pci buses */
286 static void pci_rescan_worker(struct work_struct *work)
287 {
288 pci_rescan();
289 }
290
291 static int enable_slot(struct hotplug_slot *hotplug_slot)
292 {
293 /* mis-use enable_slot for rescanning of the pci bus */
294 cancel_work_sync(&pci_rescan_work);
295 queue_work(dummyphp_wq, &pci_rescan_work);
296 return -ENODEV;
297 }
298
299 /* find the hotplug_slot for the pci_dev */
300 static struct hotplug_slot *get_slot_from_dev(struct pci_dev *dev)
301 {
302 struct dummy_slot *dslot;
303
304 list_for_each_entry(dslot, &slot_list, node) {
305 if (dslot->dev == dev)
306 return dslot->slot;
307 }
308 return NULL;
309 }
310
311
312 static int disable_slot(struct hotplug_slot *slot)
313 {
314 struct dummy_slot *dslot;
315 struct hotplug_slot *hslot;
316 struct pci_dev *dev;
317 int func;
318
319 if (!slot)
320 return -ENODEV;
321 dslot = slot->private;
322
323 dbg("%s - physical_slot = %s\n", __FUNCTION__, slot->name);
324
325 /* don't disable bridged devices just yet, we can't handle them easily... */
326 if (dslot->dev->subordinate) {
327 err("Can't remove PCI devices with other PCI devices behind it yet.\n");
328 return -ENODEV;
329 }
330 if (test_and_set_bit(0, &dslot->removed)) {
331 dbg("Slot already scheduled for removal\n");
332 return -ENODEV;
333 }
334 /* search for subfunctions and disable them first */
335 if (!(dslot->dev->devfn & 7)) {
336 for (func = 1; func < 8; func++) {
337 dev = pci_get_slot(dslot->dev->bus,
338 dslot->dev->devfn + func);
339 if (dev) {
340 hslot = get_slot_from_dev(dev);
341 if (hslot)
342 disable_slot(hslot);
343 else {
344 err("Hotplug slot not found for subfunction of PCI device\n");
345 return -ENODEV;
346 }
347 pci_dev_put(dev);
348 } else
349 dbg("No device in slot found\n");
350 }
351 }
352
353 /* remove the device from the pci core */
354 pci_remove_bus_device(dslot->dev);
355
356 /* queue work item to blow away this sysfs entry and other parts. */
357 INIT_WORK(&dslot->remove_work, remove_slot_worker);
358 queue_work(dummyphp_wq, &dslot->remove_work);
359
360 return 0;
361 }
362
363 static void cleanup_slots (void)
364 {
365 struct list_head *tmp;
366 struct list_head *next;
367 struct dummy_slot *dslot;
368
369 destroy_workqueue(dummyphp_wq);
370 list_for_each_safe (tmp, next, &slot_list) {
371 dslot = list_entry (tmp, struct dummy_slot, node);
372 remove_slot(dslot);
373 }
374
375 }
376
377 static int __init dummyphp_init(void)
378 {
379 info(DRIVER_DESC "\n");
380
381 dummyphp_wq = create_singlethread_workqueue(MY_NAME);
382 if (!dummyphp_wq)
383 return -ENOMEM;
384
385 return pci_scan_buses();
386 }
387
388
389 static void __exit dummyphp_exit(void)
390 {
391 cleanup_slots();
392 }
393
394 module_init(dummyphp_init);
395 module_exit(dummyphp_exit);
396
397 MODULE_AUTHOR(DRIVER_AUTHOR);
398 MODULE_DESCRIPTION(DRIVER_DESC);
399 MODULE_LICENSE("GPL");
400 module_param(debug, bool, S_IRUGO | S_IWUSR);
401 MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
402
403
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