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
34static const struct bus_type ccwgroup_bus_type;
35
36static 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 */
56int 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;
71out:
72 atomic_set(v: &gdev->onoff, i: 0);
73 return ret;
74}
75EXPORT_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 */
86int 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
104offline:
105 gdev->state = CCWGROUP_OFFLINE;
106out:
107 atomic_set(v: &gdev->onoff, i: 0);
108 return ret;
109}
110EXPORT_SYMBOL(ccwgroup_set_offline);
111
112static 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;
136out:
137 device_unlock(dev);
138 return (ret == 0) ? count : ret;
139}
140
141static 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 */
157static 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
167static 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;
186out:
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}
194static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
195static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
196
197static struct attribute *ccwgroup_dev_attrs[] = {
198 &dev_attr_online.attr,
199 &dev_attr_ungroup.attr,
200 NULL,
201};
202ATTRIBUTE_GROUPS(ccwgroup_dev);
203
204static 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
213static 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
234static 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
267static 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 */
313int 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;
398error:
399 mutex_unlock(lock: &gdev->reg_mutex);
400 put_device(dev: &gdev->dev);
401 return rc;
402}
403EXPORT_SYMBOL(ccwgroup_create_dev);
404
405static 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
418static struct notifier_block ccwgroup_nb = {
419 .notifier_call = ccwgroup_notifier
420};
421
422static 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
437static 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
443module_init(init_ccwgroup);
444module_exit(cleanup_ccwgroup);
445
446/************************** driver stuff ******************************/
447
448static 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
457static 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
468static 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
475bool dev_is_ccwgroup(struct device *dev)
476{
477 return dev->bus == &ccwgroup_bus_type;
478}
479EXPORT_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 */
487int 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}
494EXPORT_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 */
502void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
503{
504 driver_unregister(drv: &cdriver->driver);
505}
506EXPORT_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 */
517int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
518{
519 return 0;
520}
521EXPORT_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 */
531void 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}
552EXPORT_SYMBOL(ccwgroup_remove_ccwdev);
553MODULE_LICENSE("GPL");
554

source code of linux/drivers/s390/cio/ccwgroup.c