1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * bus driver for ccwgroup |
4 | * |
5 | * Copyright IBM Corp. 2002, 2012 |
6 | * |
7 | * Author(s): Arnd Bergmann (arndb@de.ibm.com) |
8 | * Cornelia Huck (cornelia.huck@de.ibm.com) |
9 | */ |
10 | #include <linux/module.h> |
11 | #include <linux/errno.h> |
12 | #include <linux/slab.h> |
13 | #include <linux/list.h> |
14 | #include <linux/device.h> |
15 | #include <linux/init.h> |
16 | #include <linux/ctype.h> |
17 | #include <linux/dcache.h> |
18 | |
19 | #include <asm/cio.h> |
20 | #include <asm/ccwdev.h> |
21 | #include <asm/ccwgroup.h> |
22 | |
23 | #include "device.h" |
24 | |
25 | #define CCW_BUS_ID_SIZE 10 |
26 | |
27 | /* In Linux 2.4, we had a channel device layer called "chandev" |
28 | * that did all sorts of obscure stuff for networking devices. |
29 | * This is another driver that serves as a replacement for just |
30 | * one of its functions, namely the translation of single subchannels |
31 | * to devices that use multiple subchannels. |
32 | */ |
33 | |
34 | static const struct bus_type ccwgroup_bus_type; |
35 | |
36 | static void __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev) |
37 | { |
38 | int i; |
39 | char str[16]; |
40 | |
41 | for (i = 0; i < gdev->count; i++) { |
42 | sprintf(buf: str, fmt: "cdev%d" , i); |
43 | sysfs_remove_link(kobj: &gdev->dev.kobj, name: str); |
44 | sysfs_remove_link(kobj: &gdev->cdev[i]->dev.kobj, name: "group_device" ); |
45 | } |
46 | } |
47 | |
48 | /** |
49 | * ccwgroup_set_online() - enable a ccwgroup device |
50 | * @gdev: target ccwgroup device |
51 | * |
52 | * This function attempts to put the ccwgroup device into the online state. |
53 | * Returns: |
54 | * %0 on success and a negative error value on failure. |
55 | */ |
56 | int ccwgroup_set_online(struct ccwgroup_device *gdev) |
57 | { |
58 | struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver); |
59 | int ret = -EINVAL; |
60 | |
61 | if (atomic_cmpxchg(v: &gdev->onoff, old: 0, new: 1) != 0) |
62 | return -EAGAIN; |
63 | if (gdev->state == CCWGROUP_ONLINE) |
64 | goto out; |
65 | if (gdrv->set_online) |
66 | ret = gdrv->set_online(gdev); |
67 | if (ret) |
68 | goto out; |
69 | |
70 | gdev->state = CCWGROUP_ONLINE; |
71 | out: |
72 | atomic_set(v: &gdev->onoff, i: 0); |
73 | return ret; |
74 | } |
75 | EXPORT_SYMBOL(ccwgroup_set_online); |
76 | |
77 | /** |
78 | * ccwgroup_set_offline() - disable a ccwgroup device |
79 | * @gdev: target ccwgroup device |
80 | * @call_gdrv: Call the registered gdrv set_offline function |
81 | * |
82 | * This function attempts to put the ccwgroup device into the offline state. |
83 | * Returns: |
84 | * %0 on success and a negative error value on failure. |
85 | */ |
86 | int ccwgroup_set_offline(struct ccwgroup_device *gdev, bool call_gdrv) |
87 | { |
88 | struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver); |
89 | int ret = -EINVAL; |
90 | |
91 | if (atomic_cmpxchg(v: &gdev->onoff, old: 0, new: 1) != 0) |
92 | return -EAGAIN; |
93 | if (gdev->state == CCWGROUP_OFFLINE) |
94 | goto out; |
95 | if (!call_gdrv) { |
96 | ret = 0; |
97 | goto offline; |
98 | } |
99 | if (gdrv->set_offline) |
100 | ret = gdrv->set_offline(gdev); |
101 | if (ret) |
102 | goto out; |
103 | |
104 | offline: |
105 | gdev->state = CCWGROUP_OFFLINE; |
106 | out: |
107 | atomic_set(v: &gdev->onoff, i: 0); |
108 | return ret; |
109 | } |
110 | EXPORT_SYMBOL(ccwgroup_set_offline); |
111 | |
112 | static ssize_t ccwgroup_online_store(struct device *dev, |
113 | struct device_attribute *attr, |
114 | const char *buf, size_t count) |
115 | { |
116 | struct ccwgroup_device *gdev = to_ccwgroupdev(dev); |
117 | unsigned long value; |
118 | int ret; |
119 | |
120 | device_lock(dev); |
121 | if (!dev->driver) { |
122 | ret = -EINVAL; |
123 | goto out; |
124 | } |
125 | |
126 | ret = kstrtoul(s: buf, base: 0, res: &value); |
127 | if (ret) |
128 | goto out; |
129 | |
130 | if (value == 1) |
131 | ret = ccwgroup_set_online(gdev); |
132 | else if (value == 0) |
133 | ret = ccwgroup_set_offline(gdev, true); |
134 | else |
135 | ret = -EINVAL; |
136 | out: |
137 | device_unlock(dev); |
138 | return (ret == 0) ? count : ret; |
139 | } |
140 | |
141 | static ssize_t ccwgroup_online_show(struct device *dev, |
142 | struct device_attribute *attr, |
143 | char *buf) |
144 | { |
145 | struct ccwgroup_device *gdev = to_ccwgroupdev(dev); |
146 | int online; |
147 | |
148 | online = (gdev->state == CCWGROUP_ONLINE) ? 1 : 0; |
149 | |
150 | return scnprintf(buf, PAGE_SIZE, fmt: "%d\n" , online); |
151 | } |
152 | |
153 | /* |
154 | * Provide an 'ungroup' attribute so the user can remove group devices no |
155 | * longer needed or accidentally created. Saves memory :) |
156 | */ |
157 | static void ccwgroup_ungroup(struct ccwgroup_device *gdev) |
158 | { |
159 | mutex_lock(&gdev->reg_mutex); |
160 | if (device_is_registered(dev: &gdev->dev)) { |
161 | __ccwgroup_remove_symlinks(gdev); |
162 | device_unregister(dev: &gdev->dev); |
163 | } |
164 | mutex_unlock(lock: &gdev->reg_mutex); |
165 | } |
166 | |
167 | static ssize_t ccwgroup_ungroup_store(struct device *dev, |
168 | struct device_attribute *attr, |
169 | const char *buf, size_t count) |
170 | { |
171 | struct ccwgroup_device *gdev = to_ccwgroupdev(dev); |
172 | int rc = 0; |
173 | |
174 | /* Prevent concurrent online/offline processing and ungrouping. */ |
175 | if (atomic_cmpxchg(v: &gdev->onoff, old: 0, new: 1) != 0) |
176 | return -EAGAIN; |
177 | if (gdev->state != CCWGROUP_OFFLINE) { |
178 | rc = -EINVAL; |
179 | goto out; |
180 | } |
181 | |
182 | if (device_remove_file_self(dev, attr)) |
183 | ccwgroup_ungroup(gdev); |
184 | else |
185 | rc = -ENODEV; |
186 | out: |
187 | if (rc) { |
188 | /* Release onoff "lock" when ungrouping failed. */ |
189 | atomic_set(v: &gdev->onoff, i: 0); |
190 | return rc; |
191 | } |
192 | return count; |
193 | } |
194 | static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store); |
195 | static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store); |
196 | |
197 | static struct attribute *ccwgroup_dev_attrs[] = { |
198 | &dev_attr_online.attr, |
199 | &dev_attr_ungroup.attr, |
200 | NULL, |
201 | }; |
202 | ATTRIBUTE_GROUPS(ccwgroup_dev); |
203 | |
204 | static void ccwgroup_ungroup_workfn(struct work_struct *work) |
205 | { |
206 | struct ccwgroup_device *gdev = |
207 | container_of(work, struct ccwgroup_device, ungroup_work); |
208 | |
209 | ccwgroup_ungroup(gdev); |
210 | put_device(dev: &gdev->dev); |
211 | } |
212 | |
213 | static void ccwgroup_release(struct device *dev) |
214 | { |
215 | struct ccwgroup_device *gdev = to_ccwgroupdev(dev); |
216 | unsigned int i; |
217 | |
218 | for (i = 0; i < gdev->count; i++) { |
219 | struct ccw_device *cdev = gdev->cdev[i]; |
220 | unsigned long flags; |
221 | |
222 | if (cdev) { |
223 | spin_lock_irqsave(cdev->ccwlock, flags); |
224 | if (dev_get_drvdata(dev: &cdev->dev) == gdev) |
225 | dev_set_drvdata(dev: &cdev->dev, NULL); |
226 | spin_unlock_irqrestore(lock: cdev->ccwlock, flags); |
227 | put_device(dev: &cdev->dev); |
228 | } |
229 | } |
230 | |
231 | kfree(objp: gdev); |
232 | } |
233 | |
234 | static int __ccwgroup_create_symlinks(struct ccwgroup_device *gdev) |
235 | { |
236 | char str[16]; |
237 | int i, rc; |
238 | |
239 | for (i = 0; i < gdev->count; i++) { |
240 | rc = sysfs_create_link(kobj: &gdev->cdev[i]->dev.kobj, |
241 | target: &gdev->dev.kobj, name: "group_device" ); |
242 | if (rc) { |
243 | while (i--) |
244 | sysfs_remove_link(kobj: &gdev->cdev[i]->dev.kobj, |
245 | name: "group_device" ); |
246 | return rc; |
247 | } |
248 | } |
249 | for (i = 0; i < gdev->count; i++) { |
250 | sprintf(buf: str, fmt: "cdev%d" , i); |
251 | rc = sysfs_create_link(kobj: &gdev->dev.kobj, |
252 | target: &gdev->cdev[i]->dev.kobj, name: str); |
253 | if (rc) { |
254 | while (i--) { |
255 | sprintf(buf: str, fmt: "cdev%d" , i); |
256 | sysfs_remove_link(kobj: &gdev->dev.kobj, name: str); |
257 | } |
258 | for (i = 0; i < gdev->count; i++) |
259 | sysfs_remove_link(kobj: &gdev->cdev[i]->dev.kobj, |
260 | name: "group_device" ); |
261 | return rc; |
262 | } |
263 | } |
264 | return 0; |
265 | } |
266 | |
267 | static int __get_next_id(const char **buf, struct ccw_dev_id *id) |
268 | { |
269 | unsigned int cssid, ssid, devno; |
270 | int ret = 0, len; |
271 | char *start, *end; |
272 | |
273 | start = (char *)*buf; |
274 | end = strchr(start, ','); |
275 | if (!end) { |
276 | /* Last entry. Strip trailing newline, if applicable. */ |
277 | end = strchr(start, '\n'); |
278 | if (end) |
279 | *end = '\0'; |
280 | len = strlen(start) + 1; |
281 | } else { |
282 | len = end - start + 1; |
283 | end++; |
284 | } |
285 | if (len <= CCW_BUS_ID_SIZE) { |
286 | if (sscanf(start, "%2x.%1x.%04x" , &cssid, &ssid, &devno) != 3) |
287 | ret = -EINVAL; |
288 | } else |
289 | ret = -EINVAL; |
290 | |
291 | if (!ret) { |
292 | id->ssid = ssid; |
293 | id->devno = devno; |
294 | } |
295 | *buf = end; |
296 | return ret; |
297 | } |
298 | |
299 | /** |
300 | * ccwgroup_create_dev() - create and register a ccw group device |
301 | * @parent: parent device for the new device |
302 | * @gdrv: driver for the new group device |
303 | * @num_devices: number of slave devices |
304 | * @buf: buffer containing comma separated bus ids of slave devices |
305 | * |
306 | * Create and register a new ccw group device as a child of @parent. Slave |
307 | * devices are obtained from the list of bus ids given in @buf. |
308 | * Returns: |
309 | * %0 on success and an error code on failure. |
310 | * Context: |
311 | * non-atomic |
312 | */ |
313 | int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv, |
314 | int num_devices, const char *buf) |
315 | { |
316 | struct ccwgroup_device *gdev; |
317 | struct ccw_dev_id dev_id; |
318 | int rc, i; |
319 | |
320 | if (num_devices < 1) |
321 | return -EINVAL; |
322 | |
323 | gdev = kzalloc(struct_size(gdev, cdev, num_devices), GFP_KERNEL); |
324 | if (!gdev) |
325 | return -ENOMEM; |
326 | |
327 | atomic_set(v: &gdev->onoff, i: 0); |
328 | mutex_init(&gdev->reg_mutex); |
329 | mutex_lock(&gdev->reg_mutex); |
330 | INIT_WORK(&gdev->ungroup_work, ccwgroup_ungroup_workfn); |
331 | gdev->count = num_devices; |
332 | gdev->dev.bus = &ccwgroup_bus_type; |
333 | gdev->dev.parent = parent; |
334 | gdev->dev.release = ccwgroup_release; |
335 | device_initialize(dev: &gdev->dev); |
336 | |
337 | for (i = 0; i < num_devices && buf; i++) { |
338 | rc = __get_next_id(buf: &buf, id: &dev_id); |
339 | if (rc != 0) |
340 | goto error; |
341 | gdev->cdev[i] = get_ccwdev_by_dev_id(dev_id: &dev_id); |
342 | /* |
343 | * All devices have to be of the same type in |
344 | * order to be grouped. |
345 | */ |
346 | if (!gdev->cdev[i] || !gdev->cdev[i]->drv || |
347 | gdev->cdev[i]->drv != gdev->cdev[0]->drv || |
348 | gdev->cdev[i]->id.driver_info != |
349 | gdev->cdev[0]->id.driver_info) { |
350 | rc = -EINVAL; |
351 | goto error; |
352 | } |
353 | /* Don't allow a device to belong to more than one group. */ |
354 | spin_lock_irq(lock: gdev->cdev[i]->ccwlock); |
355 | if (dev_get_drvdata(dev: &gdev->cdev[i]->dev)) { |
356 | spin_unlock_irq(lock: gdev->cdev[i]->ccwlock); |
357 | rc = -EINVAL; |
358 | goto error; |
359 | } |
360 | dev_set_drvdata(dev: &gdev->cdev[i]->dev, data: gdev); |
361 | spin_unlock_irq(lock: gdev->cdev[i]->ccwlock); |
362 | } |
363 | /* Check for sufficient number of bus ids. */ |
364 | if (i < num_devices) { |
365 | rc = -EINVAL; |
366 | goto error; |
367 | } |
368 | /* Check for trailing stuff. */ |
369 | if (i == num_devices && buf && strlen(buf) > 0) { |
370 | rc = -EINVAL; |
371 | goto error; |
372 | } |
373 | /* Check if the devices are bound to the required ccw driver. */ |
374 | if (gdrv && gdrv->ccw_driver && |
375 | gdev->cdev[0]->drv != gdrv->ccw_driver) { |
376 | rc = -EINVAL; |
377 | goto error; |
378 | } |
379 | |
380 | dev_set_name(dev: &gdev->dev, name: "%s" , dev_name(dev: &gdev->cdev[0]->dev)); |
381 | |
382 | if (gdrv) { |
383 | gdev->dev.driver = &gdrv->driver; |
384 | rc = gdrv->setup ? gdrv->setup(gdev) : 0; |
385 | if (rc) |
386 | goto error; |
387 | } |
388 | rc = device_add(dev: &gdev->dev); |
389 | if (rc) |
390 | goto error; |
391 | rc = __ccwgroup_create_symlinks(gdev); |
392 | if (rc) { |
393 | device_del(dev: &gdev->dev); |
394 | goto error; |
395 | } |
396 | mutex_unlock(lock: &gdev->reg_mutex); |
397 | return 0; |
398 | error: |
399 | mutex_unlock(lock: &gdev->reg_mutex); |
400 | put_device(dev: &gdev->dev); |
401 | return rc; |
402 | } |
403 | EXPORT_SYMBOL(ccwgroup_create_dev); |
404 | |
405 | static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action, |
406 | void *data) |
407 | { |
408 | struct ccwgroup_device *gdev = to_ccwgroupdev(data); |
409 | |
410 | if (action == BUS_NOTIFY_UNBOUND_DRIVER) { |
411 | get_device(dev: &gdev->dev); |
412 | schedule_work(work: &gdev->ungroup_work); |
413 | } |
414 | |
415 | return NOTIFY_OK; |
416 | } |
417 | |
418 | static struct notifier_block ccwgroup_nb = { |
419 | .notifier_call = ccwgroup_notifier |
420 | }; |
421 | |
422 | static int __init init_ccwgroup(void) |
423 | { |
424 | int ret; |
425 | |
426 | ret = bus_register(bus: &ccwgroup_bus_type); |
427 | if (ret) |
428 | return ret; |
429 | |
430 | ret = bus_register_notifier(bus: &ccwgroup_bus_type, nb: &ccwgroup_nb); |
431 | if (ret) |
432 | bus_unregister(bus: &ccwgroup_bus_type); |
433 | |
434 | return ret; |
435 | } |
436 | |
437 | static void __exit cleanup_ccwgroup(void) |
438 | { |
439 | bus_unregister_notifier(bus: &ccwgroup_bus_type, nb: &ccwgroup_nb); |
440 | bus_unregister(bus: &ccwgroup_bus_type); |
441 | } |
442 | |
443 | module_init(init_ccwgroup); |
444 | module_exit(cleanup_ccwgroup); |
445 | |
446 | /************************** driver stuff ******************************/ |
447 | |
448 | static void ccwgroup_remove(struct device *dev) |
449 | { |
450 | struct ccwgroup_device *gdev = to_ccwgroupdev(dev); |
451 | struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver); |
452 | |
453 | if (gdrv->remove) |
454 | gdrv->remove(gdev); |
455 | } |
456 | |
457 | static void ccwgroup_shutdown(struct device *dev) |
458 | { |
459 | struct ccwgroup_device *gdev = to_ccwgroupdev(dev); |
460 | struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver); |
461 | |
462 | if (!dev->driver) |
463 | return; |
464 | if (gdrv->shutdown) |
465 | gdrv->shutdown(gdev); |
466 | } |
467 | |
468 | static const struct bus_type ccwgroup_bus_type = { |
469 | .name = "ccwgroup" , |
470 | .dev_groups = ccwgroup_dev_groups, |
471 | .remove = ccwgroup_remove, |
472 | .shutdown = ccwgroup_shutdown, |
473 | }; |
474 | |
475 | bool dev_is_ccwgroup(struct device *dev) |
476 | { |
477 | return dev->bus == &ccwgroup_bus_type; |
478 | } |
479 | EXPORT_SYMBOL(dev_is_ccwgroup); |
480 | |
481 | /** |
482 | * ccwgroup_driver_register() - register a ccw group driver |
483 | * @cdriver: driver to be registered |
484 | * |
485 | * This function is mainly a wrapper around driver_register(). |
486 | */ |
487 | int ccwgroup_driver_register(struct ccwgroup_driver *cdriver) |
488 | { |
489 | /* register our new driver with the core */ |
490 | cdriver->driver.bus = &ccwgroup_bus_type; |
491 | |
492 | return driver_register(drv: &cdriver->driver); |
493 | } |
494 | EXPORT_SYMBOL(ccwgroup_driver_register); |
495 | |
496 | /** |
497 | * ccwgroup_driver_unregister() - deregister a ccw group driver |
498 | * @cdriver: driver to be deregistered |
499 | * |
500 | * This function is mainly a wrapper around driver_unregister(). |
501 | */ |
502 | void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver) |
503 | { |
504 | driver_unregister(drv: &cdriver->driver); |
505 | } |
506 | EXPORT_SYMBOL(ccwgroup_driver_unregister); |
507 | |
508 | /** |
509 | * ccwgroup_probe_ccwdev() - probe function for slave devices |
510 | * @cdev: ccw device to be probed |
511 | * |
512 | * This is a dummy probe function for ccw devices that are slave devices in |
513 | * a ccw group device. |
514 | * Returns: |
515 | * always %0 |
516 | */ |
517 | int ccwgroup_probe_ccwdev(struct ccw_device *cdev) |
518 | { |
519 | return 0; |
520 | } |
521 | EXPORT_SYMBOL(ccwgroup_probe_ccwdev); |
522 | |
523 | /** |
524 | * ccwgroup_remove_ccwdev() - remove function for slave devices |
525 | * @cdev: ccw device to be removed |
526 | * |
527 | * This is a remove function for ccw devices that are slave devices in a ccw |
528 | * group device. It sets the ccw device offline and also deregisters the |
529 | * embedding ccw group device. |
530 | */ |
531 | void ccwgroup_remove_ccwdev(struct ccw_device *cdev) |
532 | { |
533 | struct ccwgroup_device *gdev; |
534 | |
535 | /* Ignore offlining errors, device is gone anyway. */ |
536 | ccw_device_set_offline(cdev); |
537 | /* If one of its devices is gone, the whole group is done for. */ |
538 | spin_lock_irq(lock: cdev->ccwlock); |
539 | gdev = dev_get_drvdata(dev: &cdev->dev); |
540 | if (!gdev) { |
541 | spin_unlock_irq(lock: cdev->ccwlock); |
542 | return; |
543 | } |
544 | /* Get ccwgroup device reference for local processing. */ |
545 | get_device(dev: &gdev->dev); |
546 | spin_unlock_irq(lock: cdev->ccwlock); |
547 | /* Unregister group device. */ |
548 | ccwgroup_ungroup(gdev); |
549 | /* Release ccwgroup device reference for local processing. */ |
550 | put_device(dev: &gdev->dev); |
551 | } |
552 | EXPORT_SYMBOL(ccwgroup_remove_ccwdev); |
553 | MODULE_LICENSE("GPL" ); |
554 | |