xref: /linux/drivers/misc/mei/bus.c (revision 3839a7460721b87501134697b7b90c45dcc7825d)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2012-2019, Intel Corporation. All rights reserved.
4  * Intel Management Engine Interface (Intel MEI) Linux driver
5  */
6 
7 #include <linux/module.h>
8 #include <linux/device.h>
9 #include <linux/kernel.h>
10 #include <linux/sched/signal.h>
11 #include <linux/init.h>
12 #include <linux/errno.h>
13 #include <linux/slab.h>
14 #include <linux/mutex.h>
15 #include <linux/interrupt.h>
16 #include <linux/mei_cl_bus.h>
17 
18 #include "mei_dev.h"
19 #include "client.h"
20 
21 #define to_mei_cl_driver(d) container_of(d, struct mei_cl_driver, driver)
22 
23 /**
24  * __mei_cl_send - internal client send (write)
25  *
26  * @cl: host client
27  * @buf: buffer to send
28  * @length: buffer length
29  * @mode: sending mode
30  *
31  * Return: written size bytes or < 0 on error
32  */
33 ssize_t __mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length,
34 		      unsigned int mode)
35 {
36 	struct mei_device *bus;
37 	struct mei_cl_cb *cb;
38 	ssize_t rets;
39 
40 	if (WARN_ON(!cl || !cl->dev))
41 		return -ENODEV;
42 
43 	bus = cl->dev;
44 
45 	mutex_lock(&bus->device_lock);
46 	if (bus->dev_state != MEI_DEV_ENABLED) {
47 		rets = -ENODEV;
48 		goto out;
49 	}
50 
51 	if (!mei_cl_is_connected(cl)) {
52 		rets = -ENODEV;
53 		goto out;
54 	}
55 
56 	/* Check if we have an ME client device */
57 	if (!mei_me_cl_is_active(cl->me_cl)) {
58 		rets = -ENOTTY;
59 		goto out;
60 	}
61 
62 	if (length > mei_cl_mtu(cl)) {
63 		rets = -EFBIG;
64 		goto out;
65 	}
66 
67 	while (cl->tx_cb_queued >= bus->tx_queue_limit) {
68 		mutex_unlock(&bus->device_lock);
69 		rets = wait_event_interruptible(cl->tx_wait,
70 				cl->writing_state == MEI_WRITE_COMPLETE ||
71 				(!mei_cl_is_connected(cl)));
72 		mutex_lock(&bus->device_lock);
73 		if (rets) {
74 			if (signal_pending(current))
75 				rets = -EINTR;
76 			goto out;
77 		}
78 		if (!mei_cl_is_connected(cl)) {
79 			rets = -ENODEV;
80 			goto out;
81 		}
82 	}
83 
84 	cb = mei_cl_alloc_cb(cl, length, MEI_FOP_WRITE, NULL);
85 	if (!cb) {
86 		rets = -ENOMEM;
87 		goto out;
88 	}
89 
90 	cb->internal = !!(mode & MEI_CL_IO_TX_INTERNAL);
91 	cb->blocking = !!(mode & MEI_CL_IO_TX_BLOCKING);
92 	memcpy(cb->buf.data, buf, length);
93 
94 	rets = mei_cl_write(cl, cb);
95 
96 out:
97 	mutex_unlock(&bus->device_lock);
98 
99 	return rets;
100 }
101 
102 /**
103  * __mei_cl_recv - internal client receive (read)
104  *
105  * @cl: host client
106  * @buf: buffer to receive
107  * @length: buffer length
108  * @mode: io mode
109  * @timeout: recv timeout, 0 for infinite timeout
110  *
111  * Return: read size in bytes of < 0 on error
112  */
113 ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length,
114 		      unsigned int mode, unsigned long timeout)
115 {
116 	struct mei_device *bus;
117 	struct mei_cl_cb *cb;
118 	size_t r_length;
119 	ssize_t rets;
120 	bool nonblock = !!(mode & MEI_CL_IO_RX_NONBLOCK);
121 
122 	if (WARN_ON(!cl || !cl->dev))
123 		return -ENODEV;
124 
125 	bus = cl->dev;
126 
127 	mutex_lock(&bus->device_lock);
128 	if (bus->dev_state != MEI_DEV_ENABLED) {
129 		rets = -ENODEV;
130 		goto out;
131 	}
132 
133 	cb = mei_cl_read_cb(cl, NULL);
134 	if (cb)
135 		goto copy;
136 
137 	rets = mei_cl_read_start(cl, length, NULL);
138 	if (rets && rets != -EBUSY)
139 		goto out;
140 
141 	if (nonblock) {
142 		rets = -EAGAIN;
143 		goto out;
144 	}
145 
146 	/* wait on event only if there is no other waiter */
147 	/* synchronized under device mutex */
148 	if (!waitqueue_active(&cl->rx_wait)) {
149 
150 		mutex_unlock(&bus->device_lock);
151 
152 		if (timeout) {
153 			rets = wait_event_interruptible_timeout
154 					(cl->rx_wait,
155 					(!list_empty(&cl->rd_completed)) ||
156 					(!mei_cl_is_connected(cl)),
157 					msecs_to_jiffies(timeout));
158 			if (rets == 0)
159 				return -ETIME;
160 			if (rets < 0) {
161 				if (signal_pending(current))
162 					return -EINTR;
163 				return -ERESTARTSYS;
164 			}
165 		} else {
166 			if (wait_event_interruptible
167 					(cl->rx_wait,
168 					(!list_empty(&cl->rd_completed)) ||
169 					(!mei_cl_is_connected(cl)))) {
170 				if (signal_pending(current))
171 					return -EINTR;
172 				return -ERESTARTSYS;
173 			}
174 		}
175 
176 		mutex_lock(&bus->device_lock);
177 
178 		if (!mei_cl_is_connected(cl)) {
179 			rets = -ENODEV;
180 			goto out;
181 		}
182 	}
183 
184 	cb = mei_cl_read_cb(cl, NULL);
185 	if (!cb) {
186 		rets = 0;
187 		goto out;
188 	}
189 
190 copy:
191 	if (cb->status) {
192 		rets = cb->status;
193 		goto free;
194 	}
195 
196 	r_length = min_t(size_t, length, cb->buf_idx);
197 	memcpy(buf, cb->buf.data, r_length);
198 	rets = r_length;
199 
200 free:
201 	mei_io_cb_free(cb);
202 out:
203 	mutex_unlock(&bus->device_lock);
204 
205 	return rets;
206 }
207 
208 /**
209  * mei_cldev_send - me device send  (write)
210  *
211  * @cldev: me client device
212  * @buf: buffer to send
213  * @length: buffer length
214  *
215  * Return: written size in bytes or < 0 on error
216  */
217 ssize_t mei_cldev_send(struct mei_cl_device *cldev, u8 *buf, size_t length)
218 {
219 	struct mei_cl *cl = cldev->cl;
220 
221 	return __mei_cl_send(cl, buf, length, MEI_CL_IO_TX_BLOCKING);
222 }
223 EXPORT_SYMBOL_GPL(mei_cldev_send);
224 
225 /**
226  * mei_cldev_recv_nonblock - non block client receive (read)
227  *
228  * @cldev: me client device
229  * @buf: buffer to receive
230  * @length: buffer length
231  *
232  * Return: read size in bytes of < 0 on error
233  *         -EAGAIN if function will block.
234  */
235 ssize_t mei_cldev_recv_nonblock(struct mei_cl_device *cldev, u8 *buf,
236 				size_t length)
237 {
238 	struct mei_cl *cl = cldev->cl;
239 
240 	return __mei_cl_recv(cl, buf, length, MEI_CL_IO_RX_NONBLOCK, 0);
241 }
242 EXPORT_SYMBOL_GPL(mei_cldev_recv_nonblock);
243 
244 /**
245  * mei_cldev_recv - client receive (read)
246  *
247  * @cldev: me client device
248  * @buf: buffer to receive
249  * @length: buffer length
250  *
251  * Return: read size in bytes of < 0 on error
252  */
253 ssize_t mei_cldev_recv(struct mei_cl_device *cldev, u8 *buf, size_t length)
254 {
255 	struct mei_cl *cl = cldev->cl;
256 
257 	return __mei_cl_recv(cl, buf, length, 0, 0);
258 }
259 EXPORT_SYMBOL_GPL(mei_cldev_recv);
260 
261 /**
262  * mei_cl_bus_rx_work - dispatch rx event for a bus device
263  *
264  * @work: work
265  */
266 static void mei_cl_bus_rx_work(struct work_struct *work)
267 {
268 	struct mei_cl_device *cldev;
269 	struct mei_device *bus;
270 
271 	cldev = container_of(work, struct mei_cl_device, rx_work);
272 
273 	bus = cldev->bus;
274 
275 	if (cldev->rx_cb)
276 		cldev->rx_cb(cldev);
277 
278 	mutex_lock(&bus->device_lock);
279 	mei_cl_read_start(cldev->cl, mei_cl_mtu(cldev->cl), NULL);
280 	mutex_unlock(&bus->device_lock);
281 }
282 
283 /**
284  * mei_cl_bus_notif_work - dispatch FW notif event for a bus device
285  *
286  * @work: work
287  */
288 static void mei_cl_bus_notif_work(struct work_struct *work)
289 {
290 	struct mei_cl_device *cldev;
291 
292 	cldev = container_of(work, struct mei_cl_device, notif_work);
293 
294 	if (cldev->notif_cb)
295 		cldev->notif_cb(cldev);
296 }
297 
298 /**
299  * mei_cl_bus_notify_event - schedule notify cb on bus client
300  *
301  * @cl: host client
302  *
303  * Return: true if event was scheduled
304  *         false if the client is not waiting for event
305  */
306 bool mei_cl_bus_notify_event(struct mei_cl *cl)
307 {
308 	struct mei_cl_device *cldev = cl->cldev;
309 
310 	if (!cldev || !cldev->notif_cb)
311 		return false;
312 
313 	if (!cl->notify_ev)
314 		return false;
315 
316 	schedule_work(&cldev->notif_work);
317 
318 	cl->notify_ev = false;
319 
320 	return true;
321 }
322 
323 /**
324  * mei_cl_bus_rx_event - schedule rx event
325  *
326  * @cl: host client
327  *
328  * Return: true if event was scheduled
329  *         false if the client is not waiting for event
330  */
331 bool mei_cl_bus_rx_event(struct mei_cl *cl)
332 {
333 	struct mei_cl_device *cldev = cl->cldev;
334 
335 	if (!cldev || !cldev->rx_cb)
336 		return false;
337 
338 	schedule_work(&cldev->rx_work);
339 
340 	return true;
341 }
342 
343 /**
344  * mei_cldev_register_rx_cb - register Rx event callback
345  *
346  * @cldev: me client devices
347  * @rx_cb: callback function
348  *
349  * Return: 0 on success
350  *         -EALREADY if an callback is already registered
351  *         <0 on other errors
352  */
353 int mei_cldev_register_rx_cb(struct mei_cl_device *cldev, mei_cldev_cb_t rx_cb)
354 {
355 	struct mei_device *bus = cldev->bus;
356 	int ret;
357 
358 	if (!rx_cb)
359 		return -EINVAL;
360 	if (cldev->rx_cb)
361 		return -EALREADY;
362 
363 	cldev->rx_cb = rx_cb;
364 	INIT_WORK(&cldev->rx_work, mei_cl_bus_rx_work);
365 
366 	mutex_lock(&bus->device_lock);
367 	ret = mei_cl_read_start(cldev->cl, mei_cl_mtu(cldev->cl), NULL);
368 	mutex_unlock(&bus->device_lock);
369 	if (ret && ret != -EBUSY)
370 		return ret;
371 
372 	return 0;
373 }
374 EXPORT_SYMBOL_GPL(mei_cldev_register_rx_cb);
375 
376 /**
377  * mei_cldev_register_notif_cb - register FW notification event callback
378  *
379  * @cldev: me client devices
380  * @notif_cb: callback function
381  *
382  * Return: 0 on success
383  *         -EALREADY if an callback is already registered
384  *         <0 on other errors
385  */
386 int mei_cldev_register_notif_cb(struct mei_cl_device *cldev,
387 				mei_cldev_cb_t notif_cb)
388 {
389 	struct mei_device *bus = cldev->bus;
390 	int ret;
391 
392 	if (!notif_cb)
393 		return -EINVAL;
394 
395 	if (cldev->notif_cb)
396 		return -EALREADY;
397 
398 	cldev->notif_cb = notif_cb;
399 	INIT_WORK(&cldev->notif_work, mei_cl_bus_notif_work);
400 
401 	mutex_lock(&bus->device_lock);
402 	ret = mei_cl_notify_request(cldev->cl, NULL, 1);
403 	mutex_unlock(&bus->device_lock);
404 	if (ret)
405 		return ret;
406 
407 	return 0;
408 }
409 EXPORT_SYMBOL_GPL(mei_cldev_register_notif_cb);
410 
411 /**
412  * mei_cldev_get_drvdata - driver data getter
413  *
414  * @cldev: mei client device
415  *
416  * Return: driver private data
417  */
418 void *mei_cldev_get_drvdata(const struct mei_cl_device *cldev)
419 {
420 	return dev_get_drvdata(&cldev->dev);
421 }
422 EXPORT_SYMBOL_GPL(mei_cldev_get_drvdata);
423 
424 /**
425  * mei_cldev_set_drvdata - driver data setter
426  *
427  * @cldev: mei client device
428  * @data: data to store
429  */
430 void mei_cldev_set_drvdata(struct mei_cl_device *cldev, void *data)
431 {
432 	dev_set_drvdata(&cldev->dev, data);
433 }
434 EXPORT_SYMBOL_GPL(mei_cldev_set_drvdata);
435 
436 /**
437  * mei_cldev_uuid - return uuid of the underlying me client
438  *
439  * @cldev: mei client device
440  *
441  * Return: me client uuid
442  */
443 const uuid_le *mei_cldev_uuid(const struct mei_cl_device *cldev)
444 {
445 	return mei_me_cl_uuid(cldev->me_cl);
446 }
447 EXPORT_SYMBOL_GPL(mei_cldev_uuid);
448 
449 /**
450  * mei_cldev_ver - return protocol version of the underlying me client
451  *
452  * @cldev: mei client device
453  *
454  * Return: me client protocol version
455  */
456 u8 mei_cldev_ver(const struct mei_cl_device *cldev)
457 {
458 	return mei_me_cl_ver(cldev->me_cl);
459 }
460 EXPORT_SYMBOL_GPL(mei_cldev_ver);
461 
462 /**
463  * mei_cldev_enabled - check whether the device is enabled
464  *
465  * @cldev: mei client device
466  *
467  * Return: true if me client is initialized and connected
468  */
469 bool mei_cldev_enabled(struct mei_cl_device *cldev)
470 {
471 	return mei_cl_is_connected(cldev->cl);
472 }
473 EXPORT_SYMBOL_GPL(mei_cldev_enabled);
474 
475 /**
476  * mei_cl_bus_module_get - acquire module of the underlying
477  *    hw driver.
478  *
479  * @cldev: mei client device
480  *
481  * Return: true on success; false if the module was removed.
482  */
483 static bool mei_cl_bus_module_get(struct mei_cl_device *cldev)
484 {
485 	return try_module_get(cldev->bus->dev->driver->owner);
486 }
487 
488 /**
489  * mei_cl_bus_module_put -  release the underlying hw module.
490  *
491  * @cldev: mei client device
492  */
493 static void mei_cl_bus_module_put(struct mei_cl_device *cldev)
494 {
495 	module_put(cldev->bus->dev->driver->owner);
496 }
497 
498 /**
499  * mei_cldev_enable - enable me client device
500  *     create connection with me client
501  *
502  * @cldev: me client device
503  *
504  * Return: 0 on success and < 0 on error
505  */
506 int mei_cldev_enable(struct mei_cl_device *cldev)
507 {
508 	struct mei_device *bus = cldev->bus;
509 	struct mei_cl *cl;
510 	int ret;
511 
512 	cl = cldev->cl;
513 
514 	mutex_lock(&bus->device_lock);
515 	if (cl->state == MEI_FILE_UNINITIALIZED) {
516 		ret = mei_cl_link(cl);
517 		if (ret)
518 			goto out;
519 		/* update pointers */
520 		cl->cldev = cldev;
521 	}
522 
523 	if (mei_cl_is_connected(cl)) {
524 		ret = 0;
525 		goto out;
526 	}
527 
528 	if (!mei_me_cl_is_active(cldev->me_cl)) {
529 		dev_err(&cldev->dev, "me client is not active\n");
530 		ret = -ENOTTY;
531 		goto out;
532 	}
533 
534 	ret = mei_cl_connect(cl, cldev->me_cl, NULL);
535 	if (ret < 0)
536 		dev_err(&cldev->dev, "cannot connect\n");
537 
538 out:
539 	mutex_unlock(&bus->device_lock);
540 
541 	return ret;
542 }
543 EXPORT_SYMBOL_GPL(mei_cldev_enable);
544 
545 /**
546  * mei_cldev_unregister_callbacks - internal wrapper for unregistering
547  *  callbacks.
548  *
549  * @cldev: client device
550  */
551 static void mei_cldev_unregister_callbacks(struct mei_cl_device *cldev)
552 {
553 	if (cldev->rx_cb) {
554 		cancel_work_sync(&cldev->rx_work);
555 		cldev->rx_cb = NULL;
556 	}
557 
558 	if (cldev->notif_cb) {
559 		cancel_work_sync(&cldev->notif_work);
560 		cldev->notif_cb = NULL;
561 	}
562 }
563 
564 /**
565  * mei_cldev_disable - disable me client device
566  *     disconnect form the me client
567  *
568  * @cldev: me client device
569  *
570  * Return: 0 on success and < 0 on error
571  */
572 int mei_cldev_disable(struct mei_cl_device *cldev)
573 {
574 	struct mei_device *bus;
575 	struct mei_cl *cl;
576 	int err;
577 
578 	if (!cldev)
579 		return -ENODEV;
580 
581 	cl = cldev->cl;
582 
583 	bus = cldev->bus;
584 
585 	mei_cldev_unregister_callbacks(cldev);
586 
587 	mutex_lock(&bus->device_lock);
588 
589 	if (!mei_cl_is_connected(cl)) {
590 		dev_dbg(bus->dev, "Already disconnected\n");
591 		err = 0;
592 		goto out;
593 	}
594 
595 	err = mei_cl_disconnect(cl);
596 	if (err < 0)
597 		dev_err(bus->dev, "Could not disconnect from the ME client\n");
598 
599 out:
600 	/* Flush queues and remove any pending read */
601 	mei_cl_flush_queues(cl, NULL);
602 	mei_cl_unlink(cl);
603 
604 	mutex_unlock(&bus->device_lock);
605 	return err;
606 }
607 EXPORT_SYMBOL_GPL(mei_cldev_disable);
608 
609 /**
610  * mei_cl_device_find - find matching entry in the driver id table
611  *
612  * @cldev: me client device
613  * @cldrv: me client driver
614  *
615  * Return: id on success; NULL if no id is matching
616  */
617 static const
618 struct mei_cl_device_id *mei_cl_device_find(struct mei_cl_device *cldev,
619 					    struct mei_cl_driver *cldrv)
620 {
621 	const struct mei_cl_device_id *id;
622 	const uuid_le *uuid;
623 	u8 version;
624 	bool match;
625 
626 	uuid = mei_me_cl_uuid(cldev->me_cl);
627 	version = mei_me_cl_ver(cldev->me_cl);
628 
629 	id = cldrv->id_table;
630 	while (uuid_le_cmp(NULL_UUID_LE, id->uuid)) {
631 		if (!uuid_le_cmp(*uuid, id->uuid)) {
632 			match = true;
633 
634 			if (cldev->name[0])
635 				if (strncmp(cldev->name, id->name,
636 					    sizeof(id->name)))
637 					match = false;
638 
639 			if (id->version != MEI_CL_VERSION_ANY)
640 				if (id->version != version)
641 					match = false;
642 			if (match)
643 				return id;
644 		}
645 
646 		id++;
647 	}
648 
649 	return NULL;
650 }
651 
652 /**
653  * mei_cl_device_match  - device match function
654  *
655  * @dev: device
656  * @drv: driver
657  *
658  * Return:  1 if matching device was found 0 otherwise
659  */
660 static int mei_cl_device_match(struct device *dev, struct device_driver *drv)
661 {
662 	struct mei_cl_device *cldev = to_mei_cl_device(dev);
663 	struct mei_cl_driver *cldrv = to_mei_cl_driver(drv);
664 	const struct mei_cl_device_id *found_id;
665 
666 	if (!cldev)
667 		return 0;
668 
669 	if (!cldev->do_match)
670 		return 0;
671 
672 	if (!cldrv || !cldrv->id_table)
673 		return 0;
674 
675 	found_id = mei_cl_device_find(cldev, cldrv);
676 	if (found_id)
677 		return 1;
678 
679 	return 0;
680 }
681 
682 /**
683  * mei_cl_device_probe - bus probe function
684  *
685  * @dev: device
686  *
687  * Return:  0 on success; < 0 otherwise
688  */
689 static int mei_cl_device_probe(struct device *dev)
690 {
691 	struct mei_cl_device *cldev;
692 	struct mei_cl_driver *cldrv;
693 	const struct mei_cl_device_id *id;
694 	int ret;
695 
696 	cldev = to_mei_cl_device(dev);
697 	cldrv = to_mei_cl_driver(dev->driver);
698 
699 	if (!cldev)
700 		return 0;
701 
702 	if (!cldrv || !cldrv->probe)
703 		return -ENODEV;
704 
705 	id = mei_cl_device_find(cldev, cldrv);
706 	if (!id)
707 		return -ENODEV;
708 
709 	if (!mei_cl_bus_module_get(cldev)) {
710 		dev_err(&cldev->dev, "get hw module failed");
711 		return -ENODEV;
712 	}
713 
714 	ret = cldrv->probe(cldev, id);
715 	if (ret) {
716 		mei_cl_bus_module_put(cldev);
717 		return ret;
718 	}
719 
720 	__module_get(THIS_MODULE);
721 	return 0;
722 }
723 
724 /**
725  * mei_cl_device_remove - remove device from the bus
726  *
727  * @dev: device
728  *
729  * Return:  0 on success; < 0 otherwise
730  */
731 static int mei_cl_device_remove(struct device *dev)
732 {
733 	struct mei_cl_device *cldev = to_mei_cl_device(dev);
734 	struct mei_cl_driver *cldrv;
735 	int ret = 0;
736 
737 	if (!cldev || !dev->driver)
738 		return 0;
739 
740 	cldrv = to_mei_cl_driver(dev->driver);
741 	if (cldrv->remove)
742 		ret = cldrv->remove(cldev);
743 
744 	mei_cldev_unregister_callbacks(cldev);
745 
746 	mei_cl_bus_module_put(cldev);
747 	module_put(THIS_MODULE);
748 	dev->driver = NULL;
749 	return ret;
750 
751 }
752 
753 static ssize_t name_show(struct device *dev, struct device_attribute *a,
754 			     char *buf)
755 {
756 	struct mei_cl_device *cldev = to_mei_cl_device(dev);
757 
758 	return scnprintf(buf, PAGE_SIZE, "%s", cldev->name);
759 }
760 static DEVICE_ATTR_RO(name);
761 
762 static ssize_t uuid_show(struct device *dev, struct device_attribute *a,
763 			     char *buf)
764 {
765 	struct mei_cl_device *cldev = to_mei_cl_device(dev);
766 	const uuid_le *uuid = mei_me_cl_uuid(cldev->me_cl);
767 
768 	return sprintf(buf, "%pUl", uuid);
769 }
770 static DEVICE_ATTR_RO(uuid);
771 
772 static ssize_t version_show(struct device *dev, struct device_attribute *a,
773 			     char *buf)
774 {
775 	struct mei_cl_device *cldev = to_mei_cl_device(dev);
776 	u8 version = mei_me_cl_ver(cldev->me_cl);
777 
778 	return sprintf(buf, "%02X", version);
779 }
780 static DEVICE_ATTR_RO(version);
781 
782 static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
783 			     char *buf)
784 {
785 	struct mei_cl_device *cldev = to_mei_cl_device(dev);
786 	const uuid_le *uuid = mei_me_cl_uuid(cldev->me_cl);
787 	u8 version = mei_me_cl_ver(cldev->me_cl);
788 
789 	return scnprintf(buf, PAGE_SIZE, "mei:%s:%pUl:%02X:",
790 			 cldev->name, uuid, version);
791 }
792 static DEVICE_ATTR_RO(modalias);
793 
794 static ssize_t max_conn_show(struct device *dev, struct device_attribute *a,
795 			     char *buf)
796 {
797 	struct mei_cl_device *cldev = to_mei_cl_device(dev);
798 	u8 maxconn = mei_me_cl_max_conn(cldev->me_cl);
799 
800 	return sprintf(buf, "%d", maxconn);
801 }
802 static DEVICE_ATTR_RO(max_conn);
803 
804 static ssize_t fixed_show(struct device *dev, struct device_attribute *a,
805 			  char *buf)
806 {
807 	struct mei_cl_device *cldev = to_mei_cl_device(dev);
808 	u8 fixed = mei_me_cl_fixed(cldev->me_cl);
809 
810 	return sprintf(buf, "%d", fixed);
811 }
812 static DEVICE_ATTR_RO(fixed);
813 
814 static ssize_t max_len_show(struct device *dev, struct device_attribute *a,
815 			    char *buf)
816 {
817 	struct mei_cl_device *cldev = to_mei_cl_device(dev);
818 	u32 maxlen = mei_me_cl_max_len(cldev->me_cl);
819 
820 	return sprintf(buf, "%u", maxlen);
821 }
822 static DEVICE_ATTR_RO(max_len);
823 
824 static struct attribute *mei_cldev_attrs[] = {
825 	&dev_attr_name.attr,
826 	&dev_attr_uuid.attr,
827 	&dev_attr_version.attr,
828 	&dev_attr_modalias.attr,
829 	&dev_attr_max_conn.attr,
830 	&dev_attr_fixed.attr,
831 	&dev_attr_max_len.attr,
832 	NULL,
833 };
834 ATTRIBUTE_GROUPS(mei_cldev);
835 
836 /**
837  * mei_cl_device_uevent - me client bus uevent handler
838  *
839  * @dev: device
840  * @env: uevent kobject
841  *
842  * Return: 0 on success -ENOMEM on when add_uevent_var fails
843  */
844 static int mei_cl_device_uevent(struct device *dev, struct kobj_uevent_env *env)
845 {
846 	struct mei_cl_device *cldev = to_mei_cl_device(dev);
847 	const uuid_le *uuid = mei_me_cl_uuid(cldev->me_cl);
848 	u8 version = mei_me_cl_ver(cldev->me_cl);
849 
850 	if (add_uevent_var(env, "MEI_CL_VERSION=%d", version))
851 		return -ENOMEM;
852 
853 	if (add_uevent_var(env, "MEI_CL_UUID=%pUl", uuid))
854 		return -ENOMEM;
855 
856 	if (add_uevent_var(env, "MEI_CL_NAME=%s", cldev->name))
857 		return -ENOMEM;
858 
859 	if (add_uevent_var(env, "MODALIAS=mei:%s:%pUl:%02X:",
860 			   cldev->name, uuid, version))
861 		return -ENOMEM;
862 
863 	return 0;
864 }
865 
866 static struct bus_type mei_cl_bus_type = {
867 	.name		= "mei",
868 	.dev_groups	= mei_cldev_groups,
869 	.match		= mei_cl_device_match,
870 	.probe		= mei_cl_device_probe,
871 	.remove		= mei_cl_device_remove,
872 	.uevent		= mei_cl_device_uevent,
873 };
874 
875 static struct mei_device *mei_dev_bus_get(struct mei_device *bus)
876 {
877 	if (bus)
878 		get_device(bus->dev);
879 
880 	return bus;
881 }
882 
883 static void mei_dev_bus_put(struct mei_device *bus)
884 {
885 	if (bus)
886 		put_device(bus->dev);
887 }
888 
889 static void mei_cl_bus_dev_release(struct device *dev)
890 {
891 	struct mei_cl_device *cldev = to_mei_cl_device(dev);
892 
893 	if (!cldev)
894 		return;
895 
896 	mei_me_cl_put(cldev->me_cl);
897 	mei_dev_bus_put(cldev->bus);
898 	mei_cl_unlink(cldev->cl);
899 	kfree(cldev->cl);
900 	kfree(cldev);
901 }
902 
903 static const struct device_type mei_cl_device_type = {
904 	.release = mei_cl_bus_dev_release,
905 };
906 
907 /**
908  * mei_cl_bus_set_name - set device name for me client device
909  *  <controller>-<client device>
910  *  Example: 0000:00:16.0-55213584-9a29-4916-badf-0fb7ed682aeb
911  *
912  * @cldev: me client device
913  */
914 static inline void mei_cl_bus_set_name(struct mei_cl_device *cldev)
915 {
916 	dev_set_name(&cldev->dev, "%s-%pUl",
917 		     dev_name(cldev->bus->dev),
918 		     mei_me_cl_uuid(cldev->me_cl));
919 }
920 
921 /**
922  * mei_cl_bus_dev_alloc - initialize and allocate mei client device
923  *
924  * @bus: mei device
925  * @me_cl: me client
926  *
927  * Return: allocated device structur or NULL on allocation failure
928  */
929 static struct mei_cl_device *mei_cl_bus_dev_alloc(struct mei_device *bus,
930 						  struct mei_me_client *me_cl)
931 {
932 	struct mei_cl_device *cldev;
933 	struct mei_cl *cl;
934 
935 	cldev = kzalloc(sizeof(struct mei_cl_device), GFP_KERNEL);
936 	if (!cldev)
937 		return NULL;
938 
939 	cl = mei_cl_allocate(bus);
940 	if (!cl) {
941 		kfree(cldev);
942 		return NULL;
943 	}
944 
945 	device_initialize(&cldev->dev);
946 	cldev->dev.parent = bus->dev;
947 	cldev->dev.bus    = &mei_cl_bus_type;
948 	cldev->dev.type   = &mei_cl_device_type;
949 	cldev->bus        = mei_dev_bus_get(bus);
950 	cldev->me_cl      = mei_me_cl_get(me_cl);
951 	cldev->cl         = cl;
952 	mei_cl_bus_set_name(cldev);
953 	cldev->is_added   = 0;
954 	INIT_LIST_HEAD(&cldev->bus_list);
955 
956 	return cldev;
957 }
958 
959 /**
960  * mei_cl_dev_setup - setup me client device
961  *    run fix up routines and set the device name
962  *
963  * @bus: mei device
964  * @cldev: me client device
965  *
966  * Return: true if the device is eligible for enumeration
967  */
968 static bool mei_cl_bus_dev_setup(struct mei_device *bus,
969 				 struct mei_cl_device *cldev)
970 {
971 	cldev->do_match = 1;
972 	mei_cl_bus_dev_fixup(cldev);
973 
974 	/* the device name can change during fix up */
975 	if (cldev->do_match)
976 		mei_cl_bus_set_name(cldev);
977 
978 	return cldev->do_match == 1;
979 }
980 
981 /**
982  * mei_cl_bus_dev_add - add me client devices
983  *
984  * @cldev: me client device
985  *
986  * Return: 0 on success; < 0 on failre
987  */
988 static int mei_cl_bus_dev_add(struct mei_cl_device *cldev)
989 {
990 	int ret;
991 
992 	dev_dbg(cldev->bus->dev, "adding %pUL:%02X\n",
993 		mei_me_cl_uuid(cldev->me_cl),
994 		mei_me_cl_ver(cldev->me_cl));
995 	ret = device_add(&cldev->dev);
996 	if (!ret)
997 		cldev->is_added = 1;
998 
999 	return ret;
1000 }
1001 
1002 /**
1003  * mei_cl_bus_dev_stop - stop the driver
1004  *
1005  * @cldev: me client device
1006  */
1007 static void mei_cl_bus_dev_stop(struct mei_cl_device *cldev)
1008 {
1009 	if (cldev->is_added)
1010 		device_release_driver(&cldev->dev);
1011 }
1012 
1013 /**
1014  * mei_cl_bus_dev_destroy - destroy me client devices object
1015  *
1016  * @cldev: me client device
1017  *
1018  * Locking: called under "dev->cl_bus_lock" lock
1019  */
1020 static void mei_cl_bus_dev_destroy(struct mei_cl_device *cldev)
1021 {
1022 
1023 	WARN_ON(!mutex_is_locked(&cldev->bus->cl_bus_lock));
1024 
1025 	if (!cldev->is_added)
1026 		return;
1027 
1028 	device_del(&cldev->dev);
1029 
1030 	list_del_init(&cldev->bus_list);
1031 
1032 	cldev->is_added = 0;
1033 	put_device(&cldev->dev);
1034 }
1035 
1036 /**
1037  * mei_cl_bus_remove_device - remove a devices form the bus
1038  *
1039  * @cldev: me client device
1040  */
1041 static void mei_cl_bus_remove_device(struct mei_cl_device *cldev)
1042 {
1043 	mei_cl_bus_dev_stop(cldev);
1044 	mei_cl_bus_dev_destroy(cldev);
1045 }
1046 
1047 /**
1048  * mei_cl_bus_remove_devices - remove all devices form the bus
1049  *
1050  * @bus: mei device
1051  */
1052 void mei_cl_bus_remove_devices(struct mei_device *bus)
1053 {
1054 	struct mei_cl_device *cldev, *next;
1055 
1056 	mutex_lock(&bus->cl_bus_lock);
1057 	list_for_each_entry_safe(cldev, next, &bus->device_list, bus_list)
1058 		mei_cl_bus_remove_device(cldev);
1059 	mutex_unlock(&bus->cl_bus_lock);
1060 }
1061 
1062 
1063 /**
1064  * mei_cl_bus_dev_init - allocate and initializes an mei client devices
1065  *     based on me client
1066  *
1067  * @bus: mei device
1068  * @me_cl: me client
1069  *
1070  * Locking: called under "dev->cl_bus_lock" lock
1071  */
1072 static void mei_cl_bus_dev_init(struct mei_device *bus,
1073 				struct mei_me_client *me_cl)
1074 {
1075 	struct mei_cl_device *cldev;
1076 
1077 	WARN_ON(!mutex_is_locked(&bus->cl_bus_lock));
1078 
1079 	dev_dbg(bus->dev, "initializing %pUl", mei_me_cl_uuid(me_cl));
1080 
1081 	if (me_cl->bus_added)
1082 		return;
1083 
1084 	cldev = mei_cl_bus_dev_alloc(bus, me_cl);
1085 	if (!cldev)
1086 		return;
1087 
1088 	me_cl->bus_added = true;
1089 	list_add_tail(&cldev->bus_list, &bus->device_list);
1090 
1091 }
1092 
1093 /**
1094  * mei_cl_bus_rescan - scan me clients list and add create
1095  *    devices for eligible clients
1096  *
1097  * @bus: mei device
1098  */
1099 static void mei_cl_bus_rescan(struct mei_device *bus)
1100 {
1101 	struct mei_cl_device *cldev, *n;
1102 	struct mei_me_client *me_cl;
1103 
1104 	mutex_lock(&bus->cl_bus_lock);
1105 
1106 	down_read(&bus->me_clients_rwsem);
1107 	list_for_each_entry(me_cl, &bus->me_clients, list)
1108 		mei_cl_bus_dev_init(bus, me_cl);
1109 	up_read(&bus->me_clients_rwsem);
1110 
1111 	list_for_each_entry_safe(cldev, n, &bus->device_list, bus_list) {
1112 
1113 		if (!mei_me_cl_is_active(cldev->me_cl)) {
1114 			mei_cl_bus_remove_device(cldev);
1115 			continue;
1116 		}
1117 
1118 		if (cldev->is_added)
1119 			continue;
1120 
1121 		if (mei_cl_bus_dev_setup(bus, cldev))
1122 			mei_cl_bus_dev_add(cldev);
1123 		else {
1124 			list_del_init(&cldev->bus_list);
1125 			put_device(&cldev->dev);
1126 		}
1127 	}
1128 	mutex_unlock(&bus->cl_bus_lock);
1129 
1130 	dev_dbg(bus->dev, "rescan end");
1131 }
1132 
1133 void mei_cl_bus_rescan_work(struct work_struct *work)
1134 {
1135 	struct mei_device *bus =
1136 		container_of(work, struct mei_device, bus_rescan_work);
1137 
1138 	mei_cl_bus_rescan(bus);
1139 }
1140 
1141 int __mei_cldev_driver_register(struct mei_cl_driver *cldrv,
1142 				struct module *owner)
1143 {
1144 	int err;
1145 
1146 	cldrv->driver.name = cldrv->name;
1147 	cldrv->driver.owner = owner;
1148 	cldrv->driver.bus = &mei_cl_bus_type;
1149 
1150 	err = driver_register(&cldrv->driver);
1151 	if (err)
1152 		return err;
1153 
1154 	pr_debug("mei: driver [%s] registered\n", cldrv->driver.name);
1155 
1156 	return 0;
1157 }
1158 EXPORT_SYMBOL_GPL(__mei_cldev_driver_register);
1159 
1160 void mei_cldev_driver_unregister(struct mei_cl_driver *cldrv)
1161 {
1162 	driver_unregister(&cldrv->driver);
1163 
1164 	pr_debug("mei: driver [%s] unregistered\n", cldrv->driver.name);
1165 }
1166 EXPORT_SYMBOL_GPL(mei_cldev_driver_unregister);
1167 
1168 
1169 int __init mei_cl_bus_init(void)
1170 {
1171 	return bus_register(&mei_cl_bus_type);
1172 }
1173 
1174 void __exit mei_cl_bus_exit(void)
1175 {
1176 	bus_unregister(&mei_cl_bus_type);
1177 }
1178