1// SPDX-License-Identifier: GPL-2.0
2// Copyright (c) 2011-2017, The Linux Foundation. All rights reserved.
3// Copyright (c) 2018, Linaro Limited
4
5#include <linux/kernel.h>
6#include <linux/module.h>
7#include <linux/device.h>
8#include <linux/spinlock.h>
9#include <linux/idr.h>
10#include <linux/slab.h>
11#include <linux/workqueue.h>
12#include <linux/of_device.h>
13#include <linux/soc/qcom/apr.h>
14#include <linux/soc/qcom/pdr.h>
15#include <linux/rpmsg.h>
16#include <linux/of.h>
17
18enum {
19 PR_TYPE_APR = 0,
20 PR_TYPE_GPR,
21};
22
23/* Some random values tbh which does not collide with static modules */
24#define GPR_DYNAMIC_PORT_START 0x10000000
25#define GPR_DYNAMIC_PORT_END 0x20000000
26
27struct packet_router {
28 struct rpmsg_endpoint *ch;
29 struct device *dev;
30 spinlock_t svcs_lock;
31 spinlock_t rx_lock;
32 struct idr svcs_idr;
33 int dest_domain_id;
34 int type;
35 struct pdr_handle *pdr;
36 struct workqueue_struct *rxwq;
37 struct work_struct rx_work;
38 struct list_head rx_list;
39};
40
41struct apr_rx_buf {
42 struct list_head node;
43 int len;
44 uint8_t buf[] __counted_by(len);
45};
46
47/**
48 * apr_send_pkt() - Send a apr message from apr device
49 *
50 * @adev: Pointer to previously registered apr device.
51 * @pkt: Pointer to apr packet to send
52 *
53 * Return: Will be an negative on packet size on success.
54 */
55int apr_send_pkt(struct apr_device *adev, struct apr_pkt *pkt)
56{
57 struct packet_router *apr = dev_get_drvdata(dev: adev->dev.parent);
58 struct apr_hdr *hdr;
59 unsigned long flags;
60 int ret;
61
62 spin_lock_irqsave(&adev->svc.lock, flags);
63
64 hdr = &pkt->hdr;
65 hdr->src_domain = APR_DOMAIN_APPS;
66 hdr->src_svc = adev->svc.id;
67 hdr->dest_domain = adev->domain_id;
68 hdr->dest_svc = adev->svc.id;
69
70 ret = rpmsg_trysend(ept: apr->ch, data: pkt, len: hdr->pkt_size);
71 spin_unlock_irqrestore(lock: &adev->svc.lock, flags);
72
73 return ret ? ret : hdr->pkt_size;
74}
75EXPORT_SYMBOL_GPL(apr_send_pkt);
76
77void gpr_free_port(gpr_port_t *port)
78{
79 struct packet_router *gpr = port->pr;
80 unsigned long flags;
81
82 spin_lock_irqsave(&gpr->svcs_lock, flags);
83 idr_remove(&gpr->svcs_idr, id: port->id);
84 spin_unlock_irqrestore(lock: &gpr->svcs_lock, flags);
85
86 kfree(objp: port);
87}
88EXPORT_SYMBOL_GPL(gpr_free_port);
89
90gpr_port_t *gpr_alloc_port(struct apr_device *gdev, struct device *dev,
91 gpr_port_cb cb, void *priv)
92{
93 struct packet_router *pr = dev_get_drvdata(dev: gdev->dev.parent);
94 gpr_port_t *port;
95 struct pkt_router_svc *svc;
96 int id;
97
98 port = kzalloc(sizeof(*port), GFP_KERNEL);
99 if (!port)
100 return ERR_PTR(error: -ENOMEM);
101
102 svc = port;
103 svc->callback = cb;
104 svc->pr = pr;
105 svc->priv = priv;
106 svc->dev = dev;
107 spin_lock_init(&svc->lock);
108
109 spin_lock(lock: &pr->svcs_lock);
110 id = idr_alloc_cyclic(&pr->svcs_idr, ptr: svc, GPR_DYNAMIC_PORT_START,
111 GPR_DYNAMIC_PORT_END, GFP_ATOMIC);
112 if (id < 0) {
113 dev_err(dev, "Unable to allocate dynamic GPR src port\n");
114 kfree(objp: port);
115 spin_unlock(lock: &pr->svcs_lock);
116 return ERR_PTR(error: id);
117 }
118
119 svc->id = id;
120 spin_unlock(lock: &pr->svcs_lock);
121
122 return port;
123}
124EXPORT_SYMBOL_GPL(gpr_alloc_port);
125
126static int pkt_router_send_svc_pkt(struct pkt_router_svc *svc, struct gpr_pkt *pkt)
127{
128 struct packet_router *pr = svc->pr;
129 struct gpr_hdr *hdr;
130 unsigned long flags;
131 int ret;
132
133 hdr = &pkt->hdr;
134
135 spin_lock_irqsave(&svc->lock, flags);
136 ret = rpmsg_trysend(ept: pr->ch, data: pkt, len: hdr->pkt_size);
137 spin_unlock_irqrestore(lock: &svc->lock, flags);
138
139 return ret ? ret : hdr->pkt_size;
140}
141
142int gpr_send_pkt(struct apr_device *gdev, struct gpr_pkt *pkt)
143{
144 return pkt_router_send_svc_pkt(svc: &gdev->svc, pkt);
145}
146EXPORT_SYMBOL_GPL(gpr_send_pkt);
147
148int gpr_send_port_pkt(gpr_port_t *port, struct gpr_pkt *pkt)
149{
150 return pkt_router_send_svc_pkt(svc: port, pkt);
151}
152EXPORT_SYMBOL_GPL(gpr_send_port_pkt);
153
154static void apr_dev_release(struct device *dev)
155{
156 struct apr_device *adev = to_apr_device(dev);
157
158 kfree(objp: adev);
159}
160
161static int apr_callback(struct rpmsg_device *rpdev, void *buf,
162 int len, void *priv, u32 addr)
163{
164 struct packet_router *apr = dev_get_drvdata(dev: &rpdev->dev);
165 struct apr_rx_buf *abuf;
166 unsigned long flags;
167
168 if (len <= APR_HDR_SIZE) {
169 dev_err(apr->dev, "APR: Improper apr pkt received:%p %d\n",
170 buf, len);
171 return -EINVAL;
172 }
173
174 abuf = kzalloc(struct_size(abuf, buf, len), GFP_ATOMIC);
175 if (!abuf)
176 return -ENOMEM;
177
178 abuf->len = len;
179 memcpy(abuf->buf, buf, len);
180
181 spin_lock_irqsave(&apr->rx_lock, flags);
182 list_add_tail(new: &abuf->node, head: &apr->rx_list);
183 spin_unlock_irqrestore(lock: &apr->rx_lock, flags);
184
185 queue_work(wq: apr->rxwq, work: &apr->rx_work);
186
187 return 0;
188}
189
190static int apr_do_rx_callback(struct packet_router *apr, struct apr_rx_buf *abuf)
191{
192 uint16_t hdr_size, msg_type, ver, svc_id;
193 struct pkt_router_svc *svc;
194 struct apr_device *adev;
195 struct apr_driver *adrv = NULL;
196 struct apr_resp_pkt resp;
197 struct apr_hdr *hdr;
198 unsigned long flags;
199 void *buf = abuf->buf;
200 int len = abuf->len;
201
202 hdr = buf;
203 ver = APR_HDR_FIELD_VER(hdr->hdr_field);
204 if (ver > APR_PKT_VER + 1)
205 return -EINVAL;
206
207 hdr_size = APR_HDR_FIELD_SIZE_BYTES(hdr->hdr_field);
208 if (hdr_size < APR_HDR_SIZE) {
209 dev_err(apr->dev, "APR: Wrong hdr size:%d\n", hdr_size);
210 return -EINVAL;
211 }
212
213 if (hdr->pkt_size < APR_HDR_SIZE || hdr->pkt_size != len) {
214 dev_err(apr->dev, "APR: Wrong packet size\n");
215 return -EINVAL;
216 }
217
218 msg_type = APR_HDR_FIELD_MT(hdr->hdr_field);
219 if (msg_type >= APR_MSG_TYPE_MAX) {
220 dev_err(apr->dev, "APR: Wrong message type: %d\n", msg_type);
221 return -EINVAL;
222 }
223
224 if (hdr->src_domain >= APR_DOMAIN_MAX ||
225 hdr->dest_domain >= APR_DOMAIN_MAX ||
226 hdr->src_svc >= APR_SVC_MAX ||
227 hdr->dest_svc >= APR_SVC_MAX) {
228 dev_err(apr->dev, "APR: Wrong APR header\n");
229 return -EINVAL;
230 }
231
232 svc_id = hdr->dest_svc;
233 spin_lock_irqsave(&apr->svcs_lock, flags);
234 svc = idr_find(&apr->svcs_idr, id: svc_id);
235 if (svc && svc->dev->driver) {
236 adev = svc_to_apr_device(svc);
237 adrv = to_apr_driver(adev->dev.driver);
238 }
239 spin_unlock_irqrestore(lock: &apr->svcs_lock, flags);
240
241 if (!adrv || !adev) {
242 dev_err(apr->dev, "APR: service is not registered (%d)\n",
243 svc_id);
244 return -EINVAL;
245 }
246
247 resp.hdr = *hdr;
248 resp.payload_size = hdr->pkt_size - hdr_size;
249
250 /*
251 * NOTE: hdr_size is not same as APR_HDR_SIZE as remote can include
252 * optional headers in to apr_hdr which should be ignored
253 */
254 if (resp.payload_size > 0)
255 resp.payload = buf + hdr_size;
256
257 adrv->callback(adev, &resp);
258
259 return 0;
260}
261
262static int gpr_do_rx_callback(struct packet_router *gpr, struct apr_rx_buf *abuf)
263{
264 uint16_t hdr_size, ver;
265 struct pkt_router_svc *svc = NULL;
266 struct gpr_resp_pkt resp;
267 struct gpr_hdr *hdr;
268 unsigned long flags;
269 void *buf = abuf->buf;
270 int len = abuf->len;
271
272 hdr = buf;
273 ver = hdr->version;
274 if (ver > GPR_PKT_VER + 1)
275 return -EINVAL;
276
277 hdr_size = hdr->hdr_size;
278 if (hdr_size < GPR_PKT_HEADER_WORD_SIZE) {
279 dev_err(gpr->dev, "GPR: Wrong hdr size:%d\n", hdr_size);
280 return -EINVAL;
281 }
282
283 if (hdr->pkt_size < GPR_PKT_HEADER_BYTE_SIZE || hdr->pkt_size != len) {
284 dev_err(gpr->dev, "GPR: Wrong packet size\n");
285 return -EINVAL;
286 }
287
288 resp.hdr = *hdr;
289 resp.payload_size = hdr->pkt_size - (hdr_size * 4);
290
291 /*
292 * NOTE: hdr_size is not same as GPR_HDR_SIZE as remote can include
293 * optional headers in to gpr_hdr which should be ignored
294 */
295 if (resp.payload_size > 0)
296 resp.payload = buf + (hdr_size * 4);
297
298
299 spin_lock_irqsave(&gpr->svcs_lock, flags);
300 svc = idr_find(&gpr->svcs_idr, id: hdr->dest_port);
301 spin_unlock_irqrestore(lock: &gpr->svcs_lock, flags);
302
303 if (!svc) {
304 dev_err(gpr->dev, "GPR: Port(%x) is not registered\n",
305 hdr->dest_port);
306 return -EINVAL;
307 }
308
309 if (svc->callback)
310 svc->callback(&resp, svc->priv, 0);
311
312 return 0;
313}
314
315static void apr_rxwq(struct work_struct *work)
316{
317 struct packet_router *apr = container_of(work, struct packet_router, rx_work);
318 struct apr_rx_buf *abuf, *b;
319 unsigned long flags;
320
321 if (!list_empty(head: &apr->rx_list)) {
322 list_for_each_entry_safe(abuf, b, &apr->rx_list, node) {
323 switch (apr->type) {
324 case PR_TYPE_APR:
325 apr_do_rx_callback(apr, abuf);
326 break;
327 case PR_TYPE_GPR:
328 gpr_do_rx_callback(gpr: apr, abuf);
329 break;
330 default:
331 break;
332 }
333 spin_lock_irqsave(&apr->rx_lock, flags);
334 list_del(entry: &abuf->node);
335 spin_unlock_irqrestore(lock: &apr->rx_lock, flags);
336 kfree(objp: abuf);
337 }
338 }
339}
340
341static int apr_device_match(struct device *dev, const struct device_driver *drv)
342{
343 struct apr_device *adev = to_apr_device(dev);
344 const struct apr_driver *adrv = to_apr_driver(drv);
345 const struct apr_device_id *id = adrv->id_table;
346
347 /* Attempt an OF style match first */
348 if (of_driver_match_device(dev, drv))
349 return 1;
350
351 if (!id)
352 return 0;
353
354 while (id->domain_id != 0 || id->svc_id != 0) {
355 if (id->domain_id == adev->domain_id &&
356 id->svc_id == adev->svc.id)
357 return 1;
358 id++;
359 }
360
361 return 0;
362}
363
364static int apr_device_probe(struct device *dev)
365{
366 struct apr_device *adev = to_apr_device(dev);
367 struct apr_driver *adrv = to_apr_driver(dev->driver);
368 int ret;
369
370 ret = adrv->probe(adev);
371 if (!ret)
372 adev->svc.callback = adrv->gpr_callback;
373
374 return ret;
375}
376
377static void apr_device_remove(struct device *dev)
378{
379 struct apr_device *adev = to_apr_device(dev);
380 struct apr_driver *adrv = to_apr_driver(dev->driver);
381 struct packet_router *apr = dev_get_drvdata(dev: adev->dev.parent);
382
383 if (adrv->remove)
384 adrv->remove(adev);
385 spin_lock(lock: &apr->svcs_lock);
386 idr_remove(&apr->svcs_idr, id: adev->svc.id);
387 spin_unlock(lock: &apr->svcs_lock);
388}
389
390static int apr_uevent(const struct device *dev, struct kobj_uevent_env *env)
391{
392 const struct apr_device *adev = to_apr_device(dev);
393 int ret;
394
395 ret = of_device_uevent_modalias(dev, env);
396 if (ret != -ENODEV)
397 return ret;
398
399 return add_uevent_var(env, format: "MODALIAS=apr:%s", adev->name);
400}
401
402const struct bus_type aprbus = {
403 .name = "aprbus",
404 .match = apr_device_match,
405 .probe = apr_device_probe,
406 .uevent = apr_uevent,
407 .remove = apr_device_remove,
408};
409EXPORT_SYMBOL_GPL(aprbus);
410
411static int apr_add_device(struct device *dev, struct device_node *np,
412 u32 svc_id, u32 domain_id)
413{
414 struct packet_router *apr = dev_get_drvdata(dev);
415 struct apr_device *adev = NULL;
416 struct pkt_router_svc *svc;
417 int ret;
418
419 adev = kzalloc(sizeof(*adev), GFP_KERNEL);
420 if (!adev)
421 return -ENOMEM;
422
423 adev->svc_id = svc_id;
424 svc = &adev->svc;
425
426 svc->id = svc_id;
427 svc->pr = apr;
428 svc->priv = adev;
429 svc->dev = dev;
430 spin_lock_init(&svc->lock);
431
432 adev->domain_id = domain_id;
433
434 if (np)
435 snprintf(buf: adev->name, APR_NAME_SIZE, fmt: "%pOFn", np);
436
437 switch (apr->type) {
438 case PR_TYPE_APR:
439 dev_set_name(dev: &adev->dev, name: "aprsvc:%s:%x:%x", adev->name,
440 domain_id, svc_id);
441 break;
442 case PR_TYPE_GPR:
443 dev_set_name(dev: &adev->dev, name: "gprsvc:%s:%x:%x", adev->name,
444 domain_id, svc_id);
445 break;
446 default:
447 break;
448 }
449
450 adev->dev.bus = &aprbus;
451 adev->dev.parent = dev;
452 adev->dev.of_node = np;
453 adev->dev.release = apr_dev_release;
454 adev->dev.driver = NULL;
455
456 spin_lock(lock: &apr->svcs_lock);
457 ret = idr_alloc(&apr->svcs_idr, ptr: svc, start: svc_id, end: svc_id + 1, GFP_ATOMIC);
458 spin_unlock(lock: &apr->svcs_lock);
459 if (ret < 0) {
460 dev_err(dev, "idr_alloc failed: %d\n", ret);
461 goto out;
462 }
463
464 /* Protection domain is optional, it does not exist on older platforms */
465 ret = of_property_read_string_index(np, propname: "qcom,protection-domain",
466 index: 1, output: &adev->service_path);
467 if (ret < 0 && ret != -EINVAL) {
468 dev_err(dev, "Failed to read second value of qcom,protection-domain\n");
469 goto out;
470 }
471
472 dev_info(dev, "Adding APR/GPR dev: %s\n", dev_name(&adev->dev));
473
474 ret = device_register(dev: &adev->dev);
475 if (ret) {
476 dev_err(dev, "device_register failed: %d\n", ret);
477 put_device(dev: &adev->dev);
478 }
479
480out:
481 return ret;
482}
483
484static int of_apr_add_pd_lookups(struct device *dev)
485{
486 const char *service_name, *service_path;
487 struct packet_router *apr = dev_get_drvdata(dev);
488 struct pdr_service *pds;
489 int ret;
490
491 for_each_child_of_node_scoped(dev->of_node, node) {
492 ret = of_property_read_string_index(np: node, propname: "qcom,protection-domain",
493 index: 0, output: &service_name);
494 if (ret < 0)
495 continue;
496
497 ret = of_property_read_string_index(np: node, propname: "qcom,protection-domain",
498 index: 1, output: &service_path);
499 if (ret < 0) {
500 dev_err(dev, "pdr service path missing: %d\n", ret);
501 return ret;
502 }
503
504 pds = pdr_add_lookup(pdr: apr->pdr, service_name, service_path);
505 if (IS_ERR(ptr: pds) && PTR_ERR(ptr: pds) != -EALREADY) {
506 dev_err(dev, "pdr add lookup failed: %ld\n", PTR_ERR(pds));
507 return PTR_ERR(ptr: pds);
508 }
509 }
510
511 return 0;
512}
513
514static void of_register_apr_devices(struct device *dev, const char *svc_path)
515{
516 struct packet_router *apr = dev_get_drvdata(dev);
517 struct device_node *node;
518 const char *service_path;
519 int ret;
520
521 for_each_child_of_node(dev->of_node, node) {
522 u32 svc_id;
523 u32 domain_id;
524
525 /*
526 * This function is called with svc_path NULL during
527 * apr_probe(), in which case we register any apr devices
528 * without a qcom,protection-domain specified.
529 *
530 * Then as the protection domains becomes available
531 * (if applicable) this function is again called, but with
532 * svc_path representing the service becoming available. In
533 * this case we register any apr devices with a matching
534 * qcom,protection-domain.
535 */
536
537 ret = of_property_read_string_index(np: node, propname: "qcom,protection-domain",
538 index: 1, output: &service_path);
539 if (svc_path) {
540 /* skip APR services that are PD independent */
541 if (ret)
542 continue;
543
544 /* skip APR services whose PD paths don't match */
545 if (strcmp(service_path, svc_path))
546 continue;
547 } else {
548 /* skip APR services whose PD lookups are registered */
549 if (ret == 0)
550 continue;
551 }
552
553 if (of_property_read_u32(np: node, propname: "reg", out_value: &svc_id))
554 continue;
555
556 domain_id = apr->dest_domain_id;
557
558 if (apr_add_device(dev, np: node, svc_id, domain_id))
559 dev_err(dev, "Failed to add apr %d svc\n", svc_id);
560 }
561}
562
563static int apr_remove_device(struct device *dev, void *svc_path)
564{
565 struct apr_device *adev = to_apr_device(dev);
566
567 if (svc_path && adev->service_path) {
568 if (!strcmp(adev->service_path, (char *)svc_path))
569 device_unregister(dev: &adev->dev);
570 } else {
571 device_unregister(dev: &adev->dev);
572 }
573
574 return 0;
575}
576
577static void apr_pd_status(int state, char *svc_path, void *priv)
578{
579 struct packet_router *apr = (struct packet_router *)priv;
580
581 switch (state) {
582 case SERVREG_SERVICE_STATE_UP:
583 of_register_apr_devices(dev: apr->dev, svc_path);
584 break;
585 case SERVREG_SERVICE_STATE_DOWN:
586 device_for_each_child(parent: apr->dev, data: svc_path, fn: apr_remove_device);
587 break;
588 }
589}
590
591static int apr_probe(struct rpmsg_device *rpdev)
592{
593 struct device *dev = &rpdev->dev;
594 struct packet_router *apr;
595 int ret;
596
597 apr = devm_kzalloc(dev, size: sizeof(*apr), GFP_KERNEL);
598 if (!apr)
599 return -ENOMEM;
600
601 ret = of_property_read_u32(np: dev->of_node, propname: "qcom,domain", out_value: &apr->dest_domain_id);
602
603 if (of_device_is_compatible(device: dev->of_node, "qcom,gpr")) {
604 apr->type = PR_TYPE_GPR;
605 } else {
606 if (ret) /* try deprecated apr-domain property */
607 ret = of_property_read_u32(np: dev->of_node, propname: "qcom,apr-domain",
608 out_value: &apr->dest_domain_id);
609 apr->type = PR_TYPE_APR;
610 }
611
612 if (ret) {
613 dev_err(dev, "Domain ID not specified in DT\n");
614 return ret;
615 }
616
617 dev_set_drvdata(dev, data: apr);
618 apr->ch = rpdev->ept;
619 apr->dev = dev;
620 apr->rxwq = create_singlethread_workqueue("qcom_apr_rx");
621 if (!apr->rxwq) {
622 dev_err(apr->dev, "Failed to start Rx WQ\n");
623 return -ENOMEM;
624 }
625 INIT_WORK(&apr->rx_work, apr_rxwq);
626
627 apr->pdr = pdr_handle_alloc(status: apr_pd_status, priv: apr);
628 if (IS_ERR(ptr: apr->pdr)) {
629 dev_err(dev, "Failed to init PDR handle\n");
630 ret = PTR_ERR(ptr: apr->pdr);
631 goto destroy_wq;
632 }
633
634 INIT_LIST_HEAD(list: &apr->rx_list);
635 spin_lock_init(&apr->rx_lock);
636 spin_lock_init(&apr->svcs_lock);
637 idr_init(idr: &apr->svcs_idr);
638
639 ret = of_apr_add_pd_lookups(dev);
640 if (ret)
641 goto handle_release;
642
643 of_register_apr_devices(dev, NULL);
644
645 return 0;
646
647handle_release:
648 pdr_handle_release(pdr: apr->pdr);
649destroy_wq:
650 destroy_workqueue(wq: apr->rxwq);
651 return ret;
652}
653
654static void apr_remove(struct rpmsg_device *rpdev)
655{
656 struct packet_router *apr = dev_get_drvdata(dev: &rpdev->dev);
657
658 pdr_handle_release(pdr: apr->pdr);
659 device_for_each_child(parent: &rpdev->dev, NULL, fn: apr_remove_device);
660 destroy_workqueue(wq: apr->rxwq);
661}
662
663/*
664 * __apr_driver_register() - Client driver registration with aprbus
665 *
666 * @drv:Client driver to be associated with client-device.
667 * @owner: owning module/driver
668 *
669 * This API will register the client driver with the aprbus
670 * It is called from the driver's module-init function.
671 */
672int __apr_driver_register(struct apr_driver *drv, struct module *owner)
673{
674 drv->driver.bus = &aprbus;
675 drv->driver.owner = owner;
676
677 return driver_register(drv: &drv->driver);
678}
679EXPORT_SYMBOL_GPL(__apr_driver_register);
680
681/*
682 * apr_driver_unregister() - Undo effect of apr_driver_register
683 *
684 * @drv: Client driver to be unregistered
685 */
686void apr_driver_unregister(struct apr_driver *drv)
687{
688 driver_unregister(drv: &drv->driver);
689}
690EXPORT_SYMBOL_GPL(apr_driver_unregister);
691
692static const struct of_device_id pkt_router_of_match[] = {
693 { .compatible = "qcom,apr"},
694 { .compatible = "qcom,apr-v2"},
695 { .compatible = "qcom,gpr"},
696 {}
697};
698MODULE_DEVICE_TABLE(of, pkt_router_of_match);
699
700static struct rpmsg_driver packet_router_driver = {
701 .probe = apr_probe,
702 .remove = apr_remove,
703 .callback = apr_callback,
704 .drv = {
705 .name = "qcom,apr",
706 .of_match_table = pkt_router_of_match,
707 },
708};
709
710static int __init apr_init(void)
711{
712 int ret;
713
714 ret = bus_register(bus: &aprbus);
715 if (!ret)
716 ret = register_rpmsg_driver(&packet_router_driver);
717 else
718 bus_unregister(bus: &aprbus);
719
720 return ret;
721}
722
723static void __exit apr_exit(void)
724{
725 bus_unregister(bus: &aprbus);
726 unregister_rpmsg_driver(drv: &packet_router_driver);
727}
728
729subsys_initcall(apr_init);
730module_exit(apr_exit);
731
732MODULE_LICENSE("GPL v2");
733MODULE_DESCRIPTION("Qualcomm APR Bus");
734

source code of linux/drivers/soc/qcom/apr.c