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4bac07c9 JF |
1 | /****************************************************************************** |
2 | * Talks to Xen Store to figure out what devices we have. | |
3 | * | |
4 | * Copyright (C) 2005 Rusty Russell, IBM Corporation | |
5 | * Copyright (C) 2005 Mike Wray, Hewlett-Packard | |
6 | * Copyright (C) 2005, 2006 XenSource Ltd | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU General Public License version 2 | |
10 | * as published by the Free Software Foundation; or, when distributed | |
11 | * separately from the Linux kernel or incorporated into other | |
12 | * software packages, subject to the following license: | |
13 | * | |
14 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
15 | * of this source file (the "Software"), to deal in the Software without | |
16 | * restriction, including without limitation the rights to use, copy, modify, | |
17 | * merge, publish, distribute, sublicense, and/or sell copies of the Software, | |
18 | * and to permit persons to whom the Software is furnished to do so, subject to | |
19 | * the following conditions: | |
20 | * | |
21 | * The above copyright notice and this permission notice shall be included in | |
22 | * all copies or substantial portions of the Software. | |
23 | * | |
24 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
25 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
26 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
27 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
28 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | |
29 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS | |
30 | * IN THE SOFTWARE. | |
31 | */ | |
32 | ||
33 | #define DPRINTK(fmt, args...) \ | |
34 | pr_debug("xenbus_probe (%s:%d) " fmt ".\n", \ | |
35 | __func__, __LINE__, ##args) | |
36 | ||
37 | #include <linux/kernel.h> | |
38 | #include <linux/err.h> | |
39 | #include <linux/string.h> | |
40 | #include <linux/ctype.h> | |
41 | #include <linux/fcntl.h> | |
42 | #include <linux/mm.h> | |
43 | #include <linux/notifier.h> | |
44 | #include <linux/kthread.h> | |
45 | #include <linux/mutex.h> | |
46 | #include <linux/io.h> | |
47 | ||
48 | #include <asm/page.h> | |
49 | #include <asm/pgtable.h> | |
50 | #include <asm/xen/hypervisor.h> | |
51 | #include <xen/xenbus.h> | |
52 | #include <xen/events.h> | |
53 | #include <xen/page.h> | |
54 | ||
55 | #include "xenbus_comms.h" | |
56 | #include "xenbus_probe.h" | |
57 | ||
58 | int xen_store_evtchn; | |
59 | struct xenstore_domain_interface *xen_store_interface; | |
60 | static unsigned long xen_store_mfn; | |
61 | ||
62 | static BLOCKING_NOTIFIER_HEAD(xenstore_chain); | |
63 | ||
64 | static void wait_for_devices(struct xenbus_driver *xendrv); | |
65 | ||
66 | static int xenbus_probe_frontend(const char *type, const char *name); | |
67 | ||
68 | static void xenbus_dev_shutdown(struct device *_dev); | |
69 | ||
70 | /* If something in array of ids matches this device, return it. */ | |
71 | static const struct xenbus_device_id * | |
72 | match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev) | |
73 | { | |
74 | for (; *arr->devicetype != '\0'; arr++) { | |
75 | if (!strcmp(arr->devicetype, dev->devicetype)) | |
76 | return arr; | |
77 | } | |
78 | return NULL; | |
79 | } | |
80 | ||
81 | int xenbus_match(struct device *_dev, struct device_driver *_drv) | |
82 | { | |
83 | struct xenbus_driver *drv = to_xenbus_driver(_drv); | |
84 | ||
85 | if (!drv->ids) | |
86 | return 0; | |
87 | ||
88 | return match_device(drv->ids, to_xenbus_device(_dev)) != NULL; | |
89 | } | |
90 | ||
91 | /* device/<type>/<id> => <type>-<id> */ | |
92 | static int frontend_bus_id(char bus_id[BUS_ID_SIZE], const char *nodename) | |
93 | { | |
94 | nodename = strchr(nodename, '/'); | |
95 | if (!nodename || strlen(nodename + 1) >= BUS_ID_SIZE) { | |
96 | printk(KERN_WARNING "XENBUS: bad frontend %s\n", nodename); | |
97 | return -EINVAL; | |
98 | } | |
99 | ||
100 | strlcpy(bus_id, nodename + 1, BUS_ID_SIZE); | |
101 | if (!strchr(bus_id, '/')) { | |
102 | printk(KERN_WARNING "XENBUS: bus_id %s no slash\n", bus_id); | |
103 | return -EINVAL; | |
104 | } | |
105 | *strchr(bus_id, '/') = '-'; | |
106 | return 0; | |
107 | } | |
108 | ||
109 | ||
110 | static void free_otherend_details(struct xenbus_device *dev) | |
111 | { | |
112 | kfree(dev->otherend); | |
113 | dev->otherend = NULL; | |
114 | } | |
115 | ||
116 | ||
117 | static void free_otherend_watch(struct xenbus_device *dev) | |
118 | { | |
119 | if (dev->otherend_watch.node) { | |
120 | unregister_xenbus_watch(&dev->otherend_watch); | |
121 | kfree(dev->otherend_watch.node); | |
122 | dev->otherend_watch.node = NULL; | |
123 | } | |
124 | } | |
125 | ||
126 | ||
127 | int read_otherend_details(struct xenbus_device *xendev, | |
128 | char *id_node, char *path_node) | |
129 | { | |
130 | int err = xenbus_gather(XBT_NIL, xendev->nodename, | |
131 | id_node, "%i", &xendev->otherend_id, | |
132 | path_node, NULL, &xendev->otherend, | |
133 | NULL); | |
134 | if (err) { | |
135 | xenbus_dev_fatal(xendev, err, | |
136 | "reading other end details from %s", | |
137 | xendev->nodename); | |
138 | return err; | |
139 | } | |
140 | if (strlen(xendev->otherend) == 0 || | |
141 | !xenbus_exists(XBT_NIL, xendev->otherend, "")) { | |
142 | xenbus_dev_fatal(xendev, -ENOENT, | |
143 | "unable to read other end from %s. " | |
144 | "missing or inaccessible.", | |
145 | xendev->nodename); | |
146 | free_otherend_details(xendev); | |
147 | return -ENOENT; | |
148 | } | |
149 | ||
150 | return 0; | |
151 | } | |
152 | ||
153 | ||
154 | static int read_backend_details(struct xenbus_device *xendev) | |
155 | { | |
156 | return read_otherend_details(xendev, "backend-id", "backend"); | |
157 | } | |
158 | ||
159 | ||
160 | /* Bus type for frontend drivers. */ | |
161 | static struct xen_bus_type xenbus_frontend = { | |
162 | .root = "device", | |
163 | .levels = 2, /* device/type/<id> */ | |
164 | .get_bus_id = frontend_bus_id, | |
165 | .probe = xenbus_probe_frontend, | |
166 | .bus = { | |
167 | .name = "xen", | |
168 | .match = xenbus_match, | |
169 | .probe = xenbus_dev_probe, | |
170 | .remove = xenbus_dev_remove, | |
171 | .shutdown = xenbus_dev_shutdown, | |
172 | }, | |
173 | }; | |
174 | ||
175 | static void otherend_changed(struct xenbus_watch *watch, | |
176 | const char **vec, unsigned int len) | |
177 | { | |
178 | struct xenbus_device *dev = | |
179 | container_of(watch, struct xenbus_device, otherend_watch); | |
180 | struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver); | |
181 | enum xenbus_state state; | |
182 | ||
183 | /* Protect us against watches firing on old details when the otherend | |
184 | details change, say immediately after a resume. */ | |
185 | if (!dev->otherend || | |
186 | strncmp(dev->otherend, vec[XS_WATCH_PATH], | |
187 | strlen(dev->otherend))) { | |
188 | dev_dbg(&dev->dev, "Ignoring watch at %s", vec[XS_WATCH_PATH]); | |
189 | return; | |
190 | } | |
191 | ||
192 | state = xenbus_read_driver_state(dev->otherend); | |
193 | ||
194 | dev_dbg(&dev->dev, "state is %d, (%s), %s, %s", | |
195 | state, xenbus_strstate(state), dev->otherend_watch.node, | |
196 | vec[XS_WATCH_PATH]); | |
197 | ||
198 | /* | |
199 | * Ignore xenbus transitions during shutdown. This prevents us doing | |
200 | * work that can fail e.g., when the rootfs is gone. | |
201 | */ | |
202 | if (system_state > SYSTEM_RUNNING) { | |
203 | struct xen_bus_type *bus = bus; | |
204 | bus = container_of(dev->dev.bus, struct xen_bus_type, bus); | |
205 | /* If we're frontend, drive the state machine to Closed. */ | |
206 | /* This should cause the backend to release our resources. */ | |
207 | if ((bus == &xenbus_frontend) && (state == XenbusStateClosing)) | |
208 | xenbus_frontend_closed(dev); | |
209 | return; | |
210 | } | |
211 | ||
212 | if (drv->otherend_changed) | |
213 | drv->otherend_changed(dev, state); | |
214 | } | |
215 | ||
216 | ||
217 | static int talk_to_otherend(struct xenbus_device *dev) | |
218 | { | |
219 | struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver); | |
220 | ||
221 | free_otherend_watch(dev); | |
222 | free_otherend_details(dev); | |
223 | ||
224 | return drv->read_otherend_details(dev); | |
225 | } | |
226 | ||
227 | ||
228 | static int watch_otherend(struct xenbus_device *dev) | |
229 | { | |
230 | return xenbus_watch_pathfmt(dev, &dev->otherend_watch, otherend_changed, | |
231 | "%s/%s", dev->otherend, "state"); | |
232 | } | |
233 | ||
234 | ||
235 | int xenbus_dev_probe(struct device *_dev) | |
236 | { | |
237 | struct xenbus_device *dev = to_xenbus_device(_dev); | |
238 | struct xenbus_driver *drv = to_xenbus_driver(_dev->driver); | |
239 | const struct xenbus_device_id *id; | |
240 | int err; | |
241 | ||
242 | DPRINTK("%s", dev->nodename); | |
243 | ||
244 | if (!drv->probe) { | |
245 | err = -ENODEV; | |
246 | goto fail; | |
247 | } | |
248 | ||
249 | id = match_device(drv->ids, dev); | |
250 | if (!id) { | |
251 | err = -ENODEV; | |
252 | goto fail; | |
253 | } | |
254 | ||
255 | err = talk_to_otherend(dev); | |
256 | if (err) { | |
257 | dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n", | |
258 | dev->nodename); | |
259 | return err; | |
260 | } | |
261 | ||
262 | err = drv->probe(dev, id); | |
263 | if (err) | |
264 | goto fail; | |
265 | ||
266 | err = watch_otherend(dev); | |
267 | if (err) { | |
268 | dev_warn(&dev->dev, "watch_otherend on %s failed.\n", | |
269 | dev->nodename); | |
270 | return err; | |
271 | } | |
272 | ||
273 | return 0; | |
274 | fail: | |
275 | xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename); | |
276 | xenbus_switch_state(dev, XenbusStateClosed); | |
277 | return -ENODEV; | |
278 | } | |
279 | ||
280 | int xenbus_dev_remove(struct device *_dev) | |
281 | { | |
282 | struct xenbus_device *dev = to_xenbus_device(_dev); | |
283 | struct xenbus_driver *drv = to_xenbus_driver(_dev->driver); | |
284 | ||
285 | DPRINTK("%s", dev->nodename); | |
286 | ||
287 | free_otherend_watch(dev); | |
288 | free_otherend_details(dev); | |
289 | ||
290 | if (drv->remove) | |
291 | drv->remove(dev); | |
292 | ||
293 | xenbus_switch_state(dev, XenbusStateClosed); | |
294 | return 0; | |
295 | } | |
296 | ||
297 | static void xenbus_dev_shutdown(struct device *_dev) | |
298 | { | |
299 | struct xenbus_device *dev = to_xenbus_device(_dev); | |
300 | unsigned long timeout = 5*HZ; | |
301 | ||
302 | DPRINTK("%s", dev->nodename); | |
303 | ||
304 | get_device(&dev->dev); | |
305 | if (dev->state != XenbusStateConnected) { | |
306 | printk(KERN_INFO "%s: %s: %s != Connected, skipping\n", __func__, | |
307 | dev->nodename, xenbus_strstate(dev->state)); | |
308 | goto out; | |
309 | } | |
310 | xenbus_switch_state(dev, XenbusStateClosing); | |
311 | timeout = wait_for_completion_timeout(&dev->down, timeout); | |
312 | if (!timeout) | |
313 | printk(KERN_INFO "%s: %s timeout closing device\n", | |
314 | __func__, dev->nodename); | |
315 | out: | |
316 | put_device(&dev->dev); | |
317 | } | |
318 | ||
319 | int xenbus_register_driver_common(struct xenbus_driver *drv, | |
320 | struct xen_bus_type *bus, | |
321 | struct module *owner, | |
322 | const char *mod_name) | |
323 | { | |
324 | drv->driver.name = drv->name; | |
325 | drv->driver.bus = &bus->bus; | |
326 | drv->driver.owner = owner; | |
327 | drv->driver.mod_name = mod_name; | |
328 | ||
329 | return driver_register(&drv->driver); | |
330 | } | |
331 | ||
332 | int __xenbus_register_frontend(struct xenbus_driver *drv, | |
333 | struct module *owner, const char *mod_name) | |
334 | { | |
335 | int ret; | |
336 | ||
337 | drv->read_otherend_details = read_backend_details; | |
338 | ||
339 | ret = xenbus_register_driver_common(drv, &xenbus_frontend, | |
340 | owner, mod_name); | |
341 | if (ret) | |
342 | return ret; | |
343 | ||
344 | /* If this driver is loaded as a module wait for devices to attach. */ | |
345 | wait_for_devices(drv); | |
346 | ||
347 | return 0; | |
348 | } | |
349 | EXPORT_SYMBOL_GPL(__xenbus_register_frontend); | |
350 | ||
351 | void xenbus_unregister_driver(struct xenbus_driver *drv) | |
352 | { | |
353 | driver_unregister(&drv->driver); | |
354 | } | |
355 | EXPORT_SYMBOL_GPL(xenbus_unregister_driver); | |
356 | ||
357 | struct xb_find_info | |
358 | { | |
359 | struct xenbus_device *dev; | |
360 | const char *nodename; | |
361 | }; | |
362 | ||
363 | static int cmp_dev(struct device *dev, void *data) | |
364 | { | |
365 | struct xenbus_device *xendev = to_xenbus_device(dev); | |
366 | struct xb_find_info *info = data; | |
367 | ||
368 | if (!strcmp(xendev->nodename, info->nodename)) { | |
369 | info->dev = xendev; | |
370 | get_device(dev); | |
371 | return 1; | |
372 | } | |
373 | return 0; | |
374 | } | |
375 | ||
376 | struct xenbus_device *xenbus_device_find(const char *nodename, | |
377 | struct bus_type *bus) | |
378 | { | |
379 | struct xb_find_info info = { .dev = NULL, .nodename = nodename }; | |
380 | ||
381 | bus_for_each_dev(bus, NULL, &info, cmp_dev); | |
382 | return info.dev; | |
383 | } | |
384 | ||
385 | static int cleanup_dev(struct device *dev, void *data) | |
386 | { | |
387 | struct xenbus_device *xendev = to_xenbus_device(dev); | |
388 | struct xb_find_info *info = data; | |
389 | int len = strlen(info->nodename); | |
390 | ||
391 | DPRINTK("%s", info->nodename); | |
392 | ||
393 | /* Match the info->nodename path, or any subdirectory of that path. */ | |
394 | if (strncmp(xendev->nodename, info->nodename, len)) | |
395 | return 0; | |
396 | ||
397 | /* If the node name is longer, ensure it really is a subdirectory. */ | |
398 | if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/')) | |
399 | return 0; | |
400 | ||
401 | info->dev = xendev; | |
402 | get_device(dev); | |
403 | return 1; | |
404 | } | |
405 | ||
406 | static void xenbus_cleanup_devices(const char *path, struct bus_type *bus) | |
407 | { | |
408 | struct xb_find_info info = { .nodename = path }; | |
409 | ||
410 | do { | |
411 | info.dev = NULL; | |
412 | bus_for_each_dev(bus, NULL, &info, cleanup_dev); | |
413 | if (info.dev) { | |
414 | device_unregister(&info.dev->dev); | |
415 | put_device(&info.dev->dev); | |
416 | } | |
417 | } while (info.dev); | |
418 | } | |
419 | ||
420 | static void xenbus_dev_release(struct device *dev) | |
421 | { | |
422 | if (dev) | |
423 | kfree(to_xenbus_device(dev)); | |
424 | } | |
425 | ||
426 | static ssize_t xendev_show_nodename(struct device *dev, | |
427 | struct device_attribute *attr, char *buf) | |
428 | { | |
429 | return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename); | |
430 | } | |
431 | DEVICE_ATTR(nodename, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_nodename, NULL); | |
432 | ||
433 | static ssize_t xendev_show_devtype(struct device *dev, | |
434 | struct device_attribute *attr, char *buf) | |
435 | { | |
436 | return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype); | |
437 | } | |
438 | DEVICE_ATTR(devtype, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_devtype, NULL); | |
439 | ||
440 | ||
441 | int xenbus_probe_node(struct xen_bus_type *bus, | |
442 | const char *type, | |
443 | const char *nodename) | |
444 | { | |
445 | int err; | |
446 | struct xenbus_device *xendev; | |
447 | size_t stringlen; | |
448 | char *tmpstring; | |
449 | ||
450 | enum xenbus_state state = xenbus_read_driver_state(nodename); | |
451 | ||
452 | if (state != XenbusStateInitialising) { | |
453 | /* Device is not new, so ignore it. This can happen if a | |
454 | device is going away after switching to Closed. */ | |
455 | return 0; | |
456 | } | |
457 | ||
458 | stringlen = strlen(nodename) + 1 + strlen(type) + 1; | |
459 | xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL); | |
460 | if (!xendev) | |
461 | return -ENOMEM; | |
462 | ||
463 | xendev->state = XenbusStateInitialising; | |
464 | ||
465 | /* Copy the strings into the extra space. */ | |
466 | ||
467 | tmpstring = (char *)(xendev + 1); | |
468 | strcpy(tmpstring, nodename); | |
469 | xendev->nodename = tmpstring; | |
470 | ||
471 | tmpstring += strlen(tmpstring) + 1; | |
472 | strcpy(tmpstring, type); | |
473 | xendev->devicetype = tmpstring; | |
474 | init_completion(&xendev->down); | |
475 | ||
476 | xendev->dev.bus = &bus->bus; | |
477 | xendev->dev.release = xenbus_dev_release; | |
478 | ||
479 | err = bus->get_bus_id(xendev->dev.bus_id, xendev->nodename); | |
480 | if (err) | |
481 | goto fail; | |
482 | ||
483 | /* Register with generic device framework. */ | |
484 | err = device_register(&xendev->dev); | |
485 | if (err) | |
486 | goto fail; | |
487 | ||
488 | err = device_create_file(&xendev->dev, &dev_attr_nodename); | |
489 | if (err) | |
490 | goto fail_unregister; | |
491 | ||
492 | err = device_create_file(&xendev->dev, &dev_attr_devtype); | |
493 | if (err) | |
494 | goto fail_remove_file; | |
495 | ||
496 | return 0; | |
497 | fail_remove_file: | |
498 | device_remove_file(&xendev->dev, &dev_attr_nodename); | |
499 | fail_unregister: | |
500 | device_unregister(&xendev->dev); | |
501 | fail: | |
502 | kfree(xendev); | |
503 | return err; | |
504 | } | |
505 | ||
506 | /* device/<typename>/<name> */ | |
507 | static int xenbus_probe_frontend(const char *type, const char *name) | |
508 | { | |
509 | char *nodename; | |
510 | int err; | |
511 | ||
512 | nodename = kasprintf(GFP_KERNEL, "%s/%s/%s", | |
513 | xenbus_frontend.root, type, name); | |
514 | if (!nodename) | |
515 | return -ENOMEM; | |
516 | ||
517 | DPRINTK("%s", nodename); | |
518 | ||
519 | err = xenbus_probe_node(&xenbus_frontend, type, nodename); | |
520 | kfree(nodename); | |
521 | return err; | |
522 | } | |
523 | ||
524 | static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type) | |
525 | { | |
526 | int err = 0; | |
527 | char **dir; | |
528 | unsigned int dir_n = 0; | |
529 | int i; | |
530 | ||
531 | dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n); | |
532 | if (IS_ERR(dir)) | |
533 | return PTR_ERR(dir); | |
534 | ||
535 | for (i = 0; i < dir_n; i++) { | |
536 | err = bus->probe(type, dir[i]); | |
537 | if (err) | |
538 | break; | |
539 | } | |
540 | kfree(dir); | |
541 | return err; | |
542 | } | |
543 | ||
544 | int xenbus_probe_devices(struct xen_bus_type *bus) | |
545 | { | |
546 | int err = 0; | |
547 | char **dir; | |
548 | unsigned int i, dir_n; | |
549 | ||
550 | dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n); | |
551 | if (IS_ERR(dir)) | |
552 | return PTR_ERR(dir); | |
553 | ||
554 | for (i = 0; i < dir_n; i++) { | |
555 | err = xenbus_probe_device_type(bus, dir[i]); | |
556 | if (err) | |
557 | break; | |
558 | } | |
559 | kfree(dir); | |
560 | return err; | |
561 | } | |
562 | ||
563 | static unsigned int char_count(const char *str, char c) | |
564 | { | |
565 | unsigned int i, ret = 0; | |
566 | ||
567 | for (i = 0; str[i]; i++) | |
568 | if (str[i] == c) | |
569 | ret++; | |
570 | return ret; | |
571 | } | |
572 | ||
573 | static int strsep_len(const char *str, char c, unsigned int len) | |
574 | { | |
575 | unsigned int i; | |
576 | ||
577 | for (i = 0; str[i]; i++) | |
578 | if (str[i] == c) { | |
579 | if (len == 0) | |
580 | return i; | |
581 | len--; | |
582 | } | |
583 | return (len == 0) ? i : -ERANGE; | |
584 | } | |
585 | ||
586 | void xenbus_dev_changed(const char *node, struct xen_bus_type *bus) | |
587 | { | |
588 | int exists, rootlen; | |
589 | struct xenbus_device *dev; | |
590 | char type[BUS_ID_SIZE]; | |
591 | const char *p, *root; | |
592 | ||
593 | if (char_count(node, '/') < 2) | |
594 | return; | |
595 | ||
596 | exists = xenbus_exists(XBT_NIL, node, ""); | |
597 | if (!exists) { | |
598 | xenbus_cleanup_devices(node, &bus->bus); | |
599 | return; | |
600 | } | |
601 | ||
602 | /* backend/<type>/... or device/<type>/... */ | |
603 | p = strchr(node, '/') + 1; | |
604 | snprintf(type, BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p); | |
605 | type[BUS_ID_SIZE-1] = '\0'; | |
606 | ||
607 | rootlen = strsep_len(node, '/', bus->levels); | |
608 | if (rootlen < 0) | |
609 | return; | |
610 | root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node); | |
611 | if (!root) | |
612 | return; | |
613 | ||
614 | dev = xenbus_device_find(root, &bus->bus); | |
615 | if (!dev) | |
616 | xenbus_probe_node(bus, type, root); | |
617 | else | |
618 | put_device(&dev->dev); | |
619 | ||
620 | kfree(root); | |
621 | } | |
622 | ||
623 | static void frontend_changed(struct xenbus_watch *watch, | |
624 | const char **vec, unsigned int len) | |
625 | { | |
626 | DPRINTK(""); | |
627 | ||
628 | xenbus_dev_changed(vec[XS_WATCH_PATH], &xenbus_frontend); | |
629 | } | |
630 | ||
631 | /* We watch for devices appearing and vanishing. */ | |
632 | static struct xenbus_watch fe_watch = { | |
633 | .node = "device", | |
634 | .callback = frontend_changed, | |
635 | }; | |
636 | ||
637 | static int suspend_dev(struct device *dev, void *data) | |
638 | { | |
639 | int err = 0; | |
640 | struct xenbus_driver *drv; | |
641 | struct xenbus_device *xdev; | |
642 | ||
643 | DPRINTK(""); | |
644 | ||
645 | if (dev->driver == NULL) | |
646 | return 0; | |
647 | drv = to_xenbus_driver(dev->driver); | |
648 | xdev = container_of(dev, struct xenbus_device, dev); | |
649 | if (drv->suspend) | |
650 | err = drv->suspend(xdev); | |
651 | if (err) | |
652 | printk(KERN_WARNING | |
653 | "xenbus: suspend %s failed: %i\n", dev->bus_id, err); | |
654 | return 0; | |
655 | } | |
656 | ||
657 | static int suspend_cancel_dev(struct device *dev, void *data) | |
658 | { | |
659 | int err = 0; | |
660 | struct xenbus_driver *drv; | |
661 | struct xenbus_device *xdev; | |
662 | ||
663 | DPRINTK(""); | |
664 | ||
665 | if (dev->driver == NULL) | |
666 | return 0; | |
667 | drv = to_xenbus_driver(dev->driver); | |
668 | xdev = container_of(dev, struct xenbus_device, dev); | |
669 | if (drv->suspend_cancel) | |
670 | err = drv->suspend_cancel(xdev); | |
671 | if (err) | |
672 | printk(KERN_WARNING | |
673 | "xenbus: suspend_cancel %s failed: %i\n", | |
674 | dev->bus_id, err); | |
675 | return 0; | |
676 | } | |
677 | ||
678 | static int resume_dev(struct device *dev, void *data) | |
679 | { | |
680 | int err; | |
681 | struct xenbus_driver *drv; | |
682 | struct xenbus_device *xdev; | |
683 | ||
684 | DPRINTK(""); | |
685 | ||
686 | if (dev->driver == NULL) | |
687 | return 0; | |
688 | ||
689 | drv = to_xenbus_driver(dev->driver); | |
690 | xdev = container_of(dev, struct xenbus_device, dev); | |
691 | ||
692 | err = talk_to_otherend(xdev); | |
693 | if (err) { | |
694 | printk(KERN_WARNING | |
695 | "xenbus: resume (talk_to_otherend) %s failed: %i\n", | |
696 | dev->bus_id, err); | |
697 | return err; | |
698 | } | |
699 | ||
700 | xdev->state = XenbusStateInitialising; | |
701 | ||
702 | if (drv->resume) { | |
703 | err = drv->resume(xdev); | |
704 | if (err) { | |
705 | printk(KERN_WARNING | |
706 | "xenbus: resume %s failed: %i\n", | |
707 | dev->bus_id, err); | |
708 | return err; | |
709 | } | |
710 | } | |
711 | ||
712 | err = watch_otherend(xdev); | |
713 | if (err) { | |
714 | printk(KERN_WARNING | |
715 | "xenbus_probe: resume (watch_otherend) %s failed: " | |
716 | "%d.\n", dev->bus_id, err); | |
717 | return err; | |
718 | } | |
719 | ||
720 | return 0; | |
721 | } | |
722 | ||
723 | void xenbus_suspend(void) | |
724 | { | |
725 | DPRINTK(""); | |
726 | ||
727 | bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, suspend_dev); | |
728 | xenbus_backend_suspend(suspend_dev); | |
729 | xs_suspend(); | |
730 | } | |
731 | EXPORT_SYMBOL_GPL(xenbus_suspend); | |
732 | ||
733 | void xenbus_resume(void) | |
734 | { | |
735 | xb_init_comms(); | |
736 | xs_resume(); | |
737 | bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, resume_dev); | |
738 | xenbus_backend_resume(resume_dev); | |
739 | } | |
740 | EXPORT_SYMBOL_GPL(xenbus_resume); | |
741 | ||
742 | void xenbus_suspend_cancel(void) | |
743 | { | |
744 | xs_suspend_cancel(); | |
745 | bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, suspend_cancel_dev); | |
746 | xenbus_backend_resume(suspend_cancel_dev); | |
747 | } | |
748 | EXPORT_SYMBOL_GPL(xenbus_suspend_cancel); | |
749 | ||
750 | /* A flag to determine if xenstored is 'ready' (i.e. has started) */ | |
751 | int xenstored_ready = 0; | |
752 | ||
753 | ||
754 | int register_xenstore_notifier(struct notifier_block *nb) | |
755 | { | |
756 | int ret = 0; | |
757 | ||
758 | if (xenstored_ready > 0) | |
759 | ret = nb->notifier_call(nb, 0, NULL); | |
760 | else | |
761 | blocking_notifier_chain_register(&xenstore_chain, nb); | |
762 | ||
763 | return ret; | |
764 | } | |
765 | EXPORT_SYMBOL_GPL(register_xenstore_notifier); | |
766 | ||
767 | void unregister_xenstore_notifier(struct notifier_block *nb) | |
768 | { | |
769 | blocking_notifier_chain_unregister(&xenstore_chain, nb); | |
770 | } | |
771 | EXPORT_SYMBOL_GPL(unregister_xenstore_notifier); | |
772 | ||
773 | void xenbus_probe(struct work_struct *unused) | |
774 | { | |
775 | BUG_ON((xenstored_ready <= 0)); | |
776 | ||
777 | /* Enumerate devices in xenstore and watch for changes. */ | |
778 | xenbus_probe_devices(&xenbus_frontend); | |
779 | register_xenbus_watch(&fe_watch); | |
780 | xenbus_backend_probe_and_watch(); | |
781 | ||
782 | /* Notify others that xenstore is up */ | |
783 | blocking_notifier_call_chain(&xenstore_chain, 0, NULL); | |
784 | } | |
785 | ||
786 | static int __init xenbus_probe_init(void) | |
787 | { | |
788 | int err = 0; | |
789 | ||
790 | DPRINTK(""); | |
791 | ||
792 | err = -ENODEV; | |
793 | if (!is_running_on_xen()) | |
794 | goto out_error; | |
795 | ||
796 | /* Register ourselves with the kernel bus subsystem */ | |
797 | err = bus_register(&xenbus_frontend.bus); | |
798 | if (err) | |
799 | goto out_error; | |
800 | ||
801 | err = xenbus_backend_bus_register(); | |
802 | if (err) | |
803 | goto out_unreg_front; | |
804 | ||
805 | /* | |
806 | * Domain0 doesn't have a store_evtchn or store_mfn yet. | |
807 | */ | |
808 | if (is_initial_xendomain()) { | |
809 | /* dom0 not yet supported */ | |
810 | } else { | |
811 | xenstored_ready = 1; | |
812 | xen_store_evtchn = xen_start_info->store_evtchn; | |
813 | xen_store_mfn = xen_start_info->store_mfn; | |
814 | } | |
815 | xen_store_interface = mfn_to_virt(xen_store_mfn); | |
816 | ||
817 | /* Initialize the interface to xenstore. */ | |
818 | err = xs_init(); | |
819 | if (err) { | |
820 | printk(KERN_WARNING | |
821 | "XENBUS: Error initializing xenstore comms: %i\n", err); | |
822 | goto out_unreg_back; | |
823 | } | |
824 | ||
825 | if (!is_initial_xendomain()) | |
826 | xenbus_probe(NULL); | |
827 | ||
828 | return 0; | |
829 | ||
830 | out_unreg_back: | |
831 | xenbus_backend_bus_unregister(); | |
832 | ||
833 | out_unreg_front: | |
834 | bus_unregister(&xenbus_frontend.bus); | |
835 | ||
836 | out_error: | |
837 | return err; | |
838 | } | |
839 | ||
840 | postcore_initcall(xenbus_probe_init); | |
841 | ||
842 | MODULE_LICENSE("GPL"); | |
843 | ||
844 | static int is_disconnected_device(struct device *dev, void *data) | |
845 | { | |
846 | struct xenbus_device *xendev = to_xenbus_device(dev); | |
847 | struct device_driver *drv = data; | |
848 | ||
849 | /* | |
850 | * A device with no driver will never connect. We care only about | |
851 | * devices which should currently be in the process of connecting. | |
852 | */ | |
853 | if (!dev->driver) | |
854 | return 0; | |
855 | ||
856 | /* Is this search limited to a particular driver? */ | |
857 | if (drv && (dev->driver != drv)) | |
858 | return 0; | |
859 | ||
860 | return (xendev->state != XenbusStateConnected); | |
861 | } | |
862 | ||
863 | static int exists_disconnected_device(struct device_driver *drv) | |
864 | { | |
865 | return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv, | |
866 | is_disconnected_device); | |
867 | } | |
868 | ||
869 | static int print_device_status(struct device *dev, void *data) | |
870 | { | |
871 | struct xenbus_device *xendev = to_xenbus_device(dev); | |
872 | struct device_driver *drv = data; | |
873 | ||
874 | /* Is this operation limited to a particular driver? */ | |
875 | if (drv && (dev->driver != drv)) | |
876 | return 0; | |
877 | ||
878 | if (!dev->driver) { | |
879 | /* Information only: is this too noisy? */ | |
880 | printk(KERN_INFO "XENBUS: Device with no driver: %s\n", | |
881 | xendev->nodename); | |
882 | } else if (xendev->state != XenbusStateConnected) { | |
883 | printk(KERN_WARNING "XENBUS: Timeout connecting " | |
884 | "to device: %s (state %d)\n", | |
885 | xendev->nodename, xendev->state); | |
886 | } | |
887 | ||
888 | return 0; | |
889 | } | |
890 | ||
891 | /* We only wait for device setup after most initcalls have run. */ | |
892 | static int ready_to_wait_for_devices; | |
893 | ||
894 | /* | |
895 | * On a 10 second timeout, wait for all devices currently configured. We need | |
896 | * to do this to guarantee that the filesystems and / or network devices | |
897 | * needed for boot are available, before we can allow the boot to proceed. | |
898 | * | |
899 | * This needs to be on a late_initcall, to happen after the frontend device | |
900 | * drivers have been initialised, but before the root fs is mounted. | |
901 | * | |
902 | * A possible improvement here would be to have the tools add a per-device | |
903 | * flag to the store entry, indicating whether it is needed at boot time. | |
904 | * This would allow people who knew what they were doing to accelerate their | |
905 | * boot slightly, but of course needs tools or manual intervention to set up | |
906 | * those flags correctly. | |
907 | */ | |
908 | static void wait_for_devices(struct xenbus_driver *xendrv) | |
909 | { | |
910 | unsigned long timeout = jiffies + 10*HZ; | |
911 | struct device_driver *drv = xendrv ? &xendrv->driver : NULL; | |
912 | ||
913 | if (!ready_to_wait_for_devices || !is_running_on_xen()) | |
914 | return; | |
915 | ||
916 | while (exists_disconnected_device(drv)) { | |
917 | if (time_after(jiffies, timeout)) | |
918 | break; | |
919 | schedule_timeout_interruptible(HZ/10); | |
920 | } | |
921 | ||
922 | bus_for_each_dev(&xenbus_frontend.bus, NULL, drv, | |
923 | print_device_status); | |
924 | } | |
925 | ||
926 | #ifndef MODULE | |
927 | static int __init boot_wait_for_devices(void) | |
928 | { | |
929 | ready_to_wait_for_devices = 1; | |
930 | wait_for_devices(NULL); | |
931 | return 0; | |
932 | } | |
933 | ||
934 | late_initcall(boot_wait_for_devices); | |
935 | #endif |