1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * HSI core.
4 *
5 * Copyright (C) 2010 Nokia Corporation. All rights reserved.
6 *
7 * Contact: Carlos Chinea <carlos.chinea@nokia.com>
8 */
9#include <linux/hsi/hsi.h>
10#include <linux/compiler.h>
11#include <linux/list.h>
12#include <linux/kobject.h>
13#include <linux/slab.h>
14#include <linux/string.h>
15#include <linux/notifier.h>
16#include <linux/of.h>
17#include <linux/of_device.h>
18#include "hsi_core.h"
19
20static ssize_t modalias_show(struct device *dev,
21 struct device_attribute *a __maybe_unused, char *buf)
22{
23 return sprintf(buf, fmt: "hsi:%s\n", dev_name(dev));
24}
25static DEVICE_ATTR_RO(modalias);
26
27static struct attribute *hsi_bus_dev_attrs[] = {
28 &dev_attr_modalias.attr,
29 NULL,
30};
31ATTRIBUTE_GROUPS(hsi_bus_dev);
32
33static int hsi_bus_uevent(const struct device *dev, struct kobj_uevent_env *env)
34{
35 add_uevent_var(env, format: "MODALIAS=hsi:%s", dev_name(dev));
36
37 return 0;
38}
39
40static int hsi_bus_match(struct device *dev, struct device_driver *driver)
41{
42 if (of_driver_match_device(dev, drv: driver))
43 return true;
44
45 if (strcmp(dev_name(dev), driver->name) == 0)
46 return true;
47
48 return false;
49}
50
51static struct bus_type hsi_bus_type = {
52 .name = "hsi",
53 .dev_groups = hsi_bus_dev_groups,
54 .match = hsi_bus_match,
55 .uevent = hsi_bus_uevent,
56};
57
58static void hsi_client_release(struct device *dev)
59{
60 struct hsi_client *cl = to_hsi_client(dev);
61
62 kfree(objp: cl->tx_cfg.channels);
63 kfree(objp: cl->rx_cfg.channels);
64 kfree(objp: cl);
65}
66
67struct hsi_client *hsi_new_client(struct hsi_port *port,
68 struct hsi_board_info *info)
69{
70 struct hsi_client *cl;
71 size_t size;
72
73 cl = kzalloc(size: sizeof(*cl), GFP_KERNEL);
74 if (!cl)
75 goto err;
76
77 cl->tx_cfg = info->tx_cfg;
78 if (cl->tx_cfg.channels) {
79 size = cl->tx_cfg.num_channels * sizeof(*cl->tx_cfg.channels);
80 cl->tx_cfg.channels = kmemdup(p: info->tx_cfg.channels, size,
81 GFP_KERNEL);
82 if (!cl->tx_cfg.channels)
83 goto err_tx;
84 }
85
86 cl->rx_cfg = info->rx_cfg;
87 if (cl->rx_cfg.channels) {
88 size = cl->rx_cfg.num_channels * sizeof(*cl->rx_cfg.channels);
89 cl->rx_cfg.channels = kmemdup(p: info->rx_cfg.channels, size,
90 GFP_KERNEL);
91 if (!cl->rx_cfg.channels)
92 goto err_rx;
93 }
94
95 cl->device.bus = &hsi_bus_type;
96 cl->device.parent = &port->device;
97 cl->device.release = hsi_client_release;
98 dev_set_name(dev: &cl->device, name: "%s", info->name);
99 cl->device.platform_data = info->platform_data;
100 if (info->archdata)
101 cl->device.archdata = *info->archdata;
102 if (device_register(dev: &cl->device) < 0) {
103 pr_err("hsi: failed to register client: %s\n", info->name);
104 put_device(dev: &cl->device);
105 goto err;
106 }
107
108 return cl;
109err_rx:
110 kfree(objp: cl->tx_cfg.channels);
111err_tx:
112 kfree(objp: cl);
113err:
114 return NULL;
115}
116EXPORT_SYMBOL_GPL(hsi_new_client);
117
118static void hsi_scan_board_info(struct hsi_controller *hsi)
119{
120 struct hsi_cl_info *cl_info;
121 struct hsi_port *p;
122
123 list_for_each_entry(cl_info, &hsi_board_list, list)
124 if (cl_info->info.hsi_id == hsi->id) {
125 p = hsi_find_port_num(hsi, num: cl_info->info.port);
126 if (!p)
127 continue;
128 hsi_new_client(p, &cl_info->info);
129 }
130}
131
132#ifdef CONFIG_OF
133static struct hsi_board_info hsi_char_dev_info = {
134 .name = "hsi_char",
135};
136
137static int hsi_of_property_parse_mode(struct device_node *client, char *name,
138 unsigned int *result)
139{
140 const char *mode;
141 int err;
142
143 err = of_property_read_string(np: client, propname: name, out_string: &mode);
144 if (err < 0)
145 return err;
146
147 if (strcmp(mode, "stream") == 0)
148 *result = HSI_MODE_STREAM;
149 else if (strcmp(mode, "frame") == 0)
150 *result = HSI_MODE_FRAME;
151 else
152 return -EINVAL;
153
154 return 0;
155}
156
157static int hsi_of_property_parse_flow(struct device_node *client, char *name,
158 unsigned int *result)
159{
160 const char *flow;
161 int err;
162
163 err = of_property_read_string(np: client, propname: name, out_string: &flow);
164 if (err < 0)
165 return err;
166
167 if (strcmp(flow, "synchronized") == 0)
168 *result = HSI_FLOW_SYNC;
169 else if (strcmp(flow, "pipeline") == 0)
170 *result = HSI_FLOW_PIPE;
171 else
172 return -EINVAL;
173
174 return 0;
175}
176
177static int hsi_of_property_parse_arb_mode(struct device_node *client,
178 char *name, unsigned int *result)
179{
180 const char *arb_mode;
181 int err;
182
183 err = of_property_read_string(np: client, propname: name, out_string: &arb_mode);
184 if (err < 0)
185 return err;
186
187 if (strcmp(arb_mode, "round-robin") == 0)
188 *result = HSI_ARB_RR;
189 else if (strcmp(arb_mode, "priority") == 0)
190 *result = HSI_ARB_PRIO;
191 else
192 return -EINVAL;
193
194 return 0;
195}
196
197static void hsi_add_client_from_dt(struct hsi_port *port,
198 struct device_node *client)
199{
200 struct hsi_client *cl;
201 struct hsi_channel channel;
202 struct property *prop;
203 char name[32];
204 int length, cells, err, i, max_chan, mode;
205
206 cl = kzalloc(size: sizeof(*cl), GFP_KERNEL);
207 if (!cl)
208 return;
209
210 err = of_alias_from_compatible(node: client, alias: name, len: sizeof(name));
211 if (err)
212 goto err;
213
214 err = hsi_of_property_parse_mode(client, name: "hsi-mode", result: &mode);
215 if (err) {
216 err = hsi_of_property_parse_mode(client, name: "hsi-rx-mode",
217 result: &cl->rx_cfg.mode);
218 if (err)
219 goto err;
220
221 err = hsi_of_property_parse_mode(client, name: "hsi-tx-mode",
222 result: &cl->tx_cfg.mode);
223 if (err)
224 goto err;
225 } else {
226 cl->rx_cfg.mode = mode;
227 cl->tx_cfg.mode = mode;
228 }
229
230 err = of_property_read_u32(np: client, propname: "hsi-speed-kbps",
231 out_value: &cl->tx_cfg.speed);
232 if (err)
233 goto err;
234 cl->rx_cfg.speed = cl->tx_cfg.speed;
235
236 err = hsi_of_property_parse_flow(client, name: "hsi-flow",
237 result: &cl->rx_cfg.flow);
238 if (err)
239 goto err;
240
241 err = hsi_of_property_parse_arb_mode(client, name: "hsi-arb-mode",
242 result: &cl->rx_cfg.arb_mode);
243 if (err)
244 goto err;
245
246 prop = of_find_property(np: client, name: "hsi-channel-ids", lenp: &length);
247 if (!prop) {
248 err = -EINVAL;
249 goto err;
250 }
251
252 cells = length / sizeof(u32);
253
254 cl->rx_cfg.num_channels = cells;
255 cl->tx_cfg.num_channels = cells;
256 cl->rx_cfg.channels = kcalloc(n: cells, size: sizeof(channel), GFP_KERNEL);
257 if (!cl->rx_cfg.channels) {
258 err = -ENOMEM;
259 goto err;
260 }
261
262 cl->tx_cfg.channels = kcalloc(n: cells, size: sizeof(channel), GFP_KERNEL);
263 if (!cl->tx_cfg.channels) {
264 err = -ENOMEM;
265 goto err2;
266 }
267
268 max_chan = 0;
269 for (i = 0; i < cells; i++) {
270 err = of_property_read_u32_index(np: client, propname: "hsi-channel-ids", index: i,
271 out_value: &channel.id);
272 if (err)
273 goto err3;
274
275 err = of_property_read_string_index(np: client, propname: "hsi-channel-names",
276 index: i, output: &channel.name);
277 if (err)
278 channel.name = NULL;
279
280 if (channel.id > max_chan)
281 max_chan = channel.id;
282
283 cl->rx_cfg.channels[i] = channel;
284 cl->tx_cfg.channels[i] = channel;
285 }
286
287 cl->rx_cfg.num_hw_channels = max_chan + 1;
288 cl->tx_cfg.num_hw_channels = max_chan + 1;
289
290 cl->device.bus = &hsi_bus_type;
291 cl->device.parent = &port->device;
292 cl->device.release = hsi_client_release;
293 cl->device.of_node = client;
294
295 dev_set_name(dev: &cl->device, name: "%s", name);
296 if (device_register(dev: &cl->device) < 0) {
297 pr_err("hsi: failed to register client: %s\n", name);
298 put_device(dev: &cl->device);
299 }
300
301 return;
302
303err3:
304 kfree(objp: cl->tx_cfg.channels);
305err2:
306 kfree(objp: cl->rx_cfg.channels);
307err:
308 kfree(objp: cl);
309 pr_err("hsi client: missing or incorrect of property: err=%d\n", err);
310}
311
312void hsi_add_clients_from_dt(struct hsi_port *port, struct device_node *clients)
313{
314 struct device_node *child;
315
316 /* register hsi-char device */
317 hsi_new_client(port, &hsi_char_dev_info);
318
319 for_each_available_child_of_node(clients, child)
320 hsi_add_client_from_dt(port, client: child);
321}
322EXPORT_SYMBOL_GPL(hsi_add_clients_from_dt);
323#endif
324
325int hsi_remove_client(struct device *dev, void *data __maybe_unused)
326{
327 device_unregister(dev);
328
329 return 0;
330}
331EXPORT_SYMBOL_GPL(hsi_remove_client);
332
333static int hsi_remove_port(struct device *dev, void *data __maybe_unused)
334{
335 device_for_each_child(dev, NULL, fn: hsi_remove_client);
336 device_unregister(dev);
337
338 return 0;
339}
340
341static void hsi_controller_release(struct device *dev)
342{
343 struct hsi_controller *hsi = to_hsi_controller(dev);
344
345 kfree(objp: hsi->port);
346 kfree(objp: hsi);
347}
348
349static void hsi_port_release(struct device *dev)
350{
351 kfree(to_hsi_port(dev));
352}
353
354/**
355 * hsi_port_unregister_clients - Unregister an HSI port
356 * @port: The HSI port to unregister
357 */
358void hsi_port_unregister_clients(struct hsi_port *port)
359{
360 device_for_each_child(dev: &port->device, NULL, fn: hsi_remove_client);
361}
362EXPORT_SYMBOL_GPL(hsi_port_unregister_clients);
363
364/**
365 * hsi_unregister_controller - Unregister an HSI controller
366 * @hsi: The HSI controller to register
367 */
368void hsi_unregister_controller(struct hsi_controller *hsi)
369{
370 device_for_each_child(dev: &hsi->device, NULL, fn: hsi_remove_port);
371 device_unregister(dev: &hsi->device);
372}
373EXPORT_SYMBOL_GPL(hsi_unregister_controller);
374
375/**
376 * hsi_register_controller - Register an HSI controller and its ports
377 * @hsi: The HSI controller to register
378 *
379 * Returns -errno on failure, 0 on success.
380 */
381int hsi_register_controller(struct hsi_controller *hsi)
382{
383 unsigned int i;
384 int err;
385
386 err = device_add(dev: &hsi->device);
387 if (err < 0)
388 return err;
389 for (i = 0; i < hsi->num_ports; i++) {
390 hsi->port[i]->device.parent = &hsi->device;
391 err = device_add(dev: &hsi->port[i]->device);
392 if (err < 0)
393 goto out;
394 }
395 /* Populate HSI bus with HSI clients */
396 hsi_scan_board_info(hsi);
397
398 return 0;
399out:
400 while (i-- > 0)
401 device_del(dev: &hsi->port[i]->device);
402 device_del(dev: &hsi->device);
403
404 return err;
405}
406EXPORT_SYMBOL_GPL(hsi_register_controller);
407
408/**
409 * hsi_register_client_driver - Register an HSI client to the HSI bus
410 * @drv: HSI client driver to register
411 *
412 * Returns -errno on failure, 0 on success.
413 */
414int hsi_register_client_driver(struct hsi_client_driver *drv)
415{
416 drv->driver.bus = &hsi_bus_type;
417
418 return driver_register(drv: &drv->driver);
419}
420EXPORT_SYMBOL_GPL(hsi_register_client_driver);
421
422static inline int hsi_dummy_msg(struct hsi_msg *msg __maybe_unused)
423{
424 return 0;
425}
426
427static inline int hsi_dummy_cl(struct hsi_client *cl __maybe_unused)
428{
429 return 0;
430}
431
432/**
433 * hsi_put_controller - Free an HSI controller
434 *
435 * @hsi: Pointer to the HSI controller to freed
436 *
437 * HSI controller drivers should only use this function if they need
438 * to free their allocated hsi_controller structures before a successful
439 * call to hsi_register_controller. Other use is not allowed.
440 */
441void hsi_put_controller(struct hsi_controller *hsi)
442{
443 unsigned int i;
444
445 if (!hsi)
446 return;
447
448 for (i = 0; i < hsi->num_ports; i++)
449 if (hsi->port && hsi->port[i])
450 put_device(dev: &hsi->port[i]->device);
451 put_device(dev: &hsi->device);
452}
453EXPORT_SYMBOL_GPL(hsi_put_controller);
454
455/**
456 * hsi_alloc_controller - Allocate an HSI controller and its ports
457 * @n_ports: Number of ports on the HSI controller
458 * @flags: Kernel allocation flags
459 *
460 * Return NULL on failure or a pointer to an hsi_controller on success.
461 */
462struct hsi_controller *hsi_alloc_controller(unsigned int n_ports, gfp_t flags)
463{
464 struct hsi_controller *hsi;
465 struct hsi_port **port;
466 unsigned int i;
467
468 if (!n_ports)
469 return NULL;
470
471 hsi = kzalloc(size: sizeof(*hsi), flags);
472 if (!hsi)
473 return NULL;
474 port = kcalloc(n: n_ports, size: sizeof(*port), flags);
475 if (!port) {
476 kfree(objp: hsi);
477 return NULL;
478 }
479 hsi->num_ports = n_ports;
480 hsi->port = port;
481 hsi->device.release = hsi_controller_release;
482 device_initialize(dev: &hsi->device);
483
484 for (i = 0; i < n_ports; i++) {
485 port[i] = kzalloc(size: sizeof(**port), flags);
486 if (port[i] == NULL)
487 goto out;
488 port[i]->num = i;
489 port[i]->async = hsi_dummy_msg;
490 port[i]->setup = hsi_dummy_cl;
491 port[i]->flush = hsi_dummy_cl;
492 port[i]->start_tx = hsi_dummy_cl;
493 port[i]->stop_tx = hsi_dummy_cl;
494 port[i]->release = hsi_dummy_cl;
495 mutex_init(&port[i]->lock);
496 BLOCKING_INIT_NOTIFIER_HEAD(&port[i]->n_head);
497 dev_set_name(dev: &port[i]->device, name: "port%d", i);
498 hsi->port[i]->device.release = hsi_port_release;
499 device_initialize(dev: &hsi->port[i]->device);
500 }
501
502 return hsi;
503out:
504 hsi_put_controller(hsi);
505
506 return NULL;
507}
508EXPORT_SYMBOL_GPL(hsi_alloc_controller);
509
510/**
511 * hsi_free_msg - Free an HSI message
512 * @msg: Pointer to the HSI message
513 *
514 * Client is responsible to free the buffers pointed by the scatterlists.
515 */
516void hsi_free_msg(struct hsi_msg *msg)
517{
518 if (!msg)
519 return;
520 sg_free_table(&msg->sgt);
521 kfree(objp: msg);
522}
523EXPORT_SYMBOL_GPL(hsi_free_msg);
524
525/**
526 * hsi_alloc_msg - Allocate an HSI message
527 * @nents: Number of memory entries
528 * @flags: Kernel allocation flags
529 *
530 * nents can be 0. This mainly makes sense for read transfer.
531 * In that case, HSI drivers will call the complete callback when
532 * there is data to be read without consuming it.
533 *
534 * Return NULL on failure or a pointer to an hsi_msg on success.
535 */
536struct hsi_msg *hsi_alloc_msg(unsigned int nents, gfp_t flags)
537{
538 struct hsi_msg *msg;
539 int err;
540
541 msg = kzalloc(size: sizeof(*msg), flags);
542 if (!msg)
543 return NULL;
544
545 if (!nents)
546 return msg;
547
548 err = sg_alloc_table(&msg->sgt, nents, flags);
549 if (unlikely(err)) {
550 kfree(objp: msg);
551 msg = NULL;
552 }
553
554 return msg;
555}
556EXPORT_SYMBOL_GPL(hsi_alloc_msg);
557
558/**
559 * hsi_async - Submit an HSI transfer to the controller
560 * @cl: HSI client sending the transfer
561 * @msg: The HSI transfer passed to controller
562 *
563 * The HSI message must have the channel, ttype, complete and destructor
564 * fields set beforehand. If nents > 0 then the client has to initialize
565 * also the scatterlists to point to the buffers to write to or read from.
566 *
567 * HSI controllers relay on pre-allocated buffers from their clients and they
568 * do not allocate buffers on their own.
569 *
570 * Once the HSI message transfer finishes, the HSI controller calls the
571 * complete callback with the status and actual_len fields of the HSI message
572 * updated. The complete callback can be called before returning from
573 * hsi_async.
574 *
575 * Returns -errno on failure or 0 on success
576 */
577int hsi_async(struct hsi_client *cl, struct hsi_msg *msg)
578{
579 struct hsi_port *port = hsi_get_port(cl);
580
581 if (!hsi_port_claimed(cl))
582 return -EACCES;
583
584 WARN_ON_ONCE(!msg->destructor || !msg->complete);
585 msg->cl = cl;
586
587 return port->async(msg);
588}
589EXPORT_SYMBOL_GPL(hsi_async);
590
591/**
592 * hsi_claim_port - Claim the HSI client's port
593 * @cl: HSI client that wants to claim its port
594 * @share: Flag to indicate if the client wants to share the port or not.
595 *
596 * Returns -errno on failure, 0 on success.
597 */
598int hsi_claim_port(struct hsi_client *cl, unsigned int share)
599{
600 struct hsi_port *port = hsi_get_port(cl);
601 int err = 0;
602
603 mutex_lock(&port->lock);
604 if ((port->claimed) && (!port->shared || !share)) {
605 err = -EBUSY;
606 goto out;
607 }
608 if (!try_module_get(to_hsi_controller(port->device.parent)->owner)) {
609 err = -ENODEV;
610 goto out;
611 }
612 port->claimed++;
613 port->shared = !!share;
614 cl->pclaimed = 1;
615out:
616 mutex_unlock(lock: &port->lock);
617
618 return err;
619}
620EXPORT_SYMBOL_GPL(hsi_claim_port);
621
622/**
623 * hsi_release_port - Release the HSI client's port
624 * @cl: HSI client which previously claimed its port
625 */
626void hsi_release_port(struct hsi_client *cl)
627{
628 struct hsi_port *port = hsi_get_port(cl);
629
630 mutex_lock(&port->lock);
631 /* Allow HW driver to do some cleanup */
632 port->release(cl);
633 if (cl->pclaimed)
634 port->claimed--;
635 BUG_ON(port->claimed < 0);
636 cl->pclaimed = 0;
637 if (!port->claimed)
638 port->shared = 0;
639 module_put(to_hsi_controller(port->device.parent)->owner);
640 mutex_unlock(lock: &port->lock);
641}
642EXPORT_SYMBOL_GPL(hsi_release_port);
643
644static int hsi_event_notifier_call(struct notifier_block *nb,
645 unsigned long event, void *data __maybe_unused)
646{
647 struct hsi_client *cl = container_of(nb, struct hsi_client, nb);
648
649 (*cl->ehandler)(cl, event);
650
651 return 0;
652}
653
654/**
655 * hsi_register_port_event - Register a client to receive port events
656 * @cl: HSI client that wants to receive port events
657 * @handler: Event handler callback
658 *
659 * Clients should register a callback to be able to receive
660 * events from the ports. Registration should happen after
661 * claiming the port.
662 * The handler can be called in interrupt context.
663 *
664 * Returns -errno on error, or 0 on success.
665 */
666int hsi_register_port_event(struct hsi_client *cl,
667 void (*handler)(struct hsi_client *, unsigned long))
668{
669 struct hsi_port *port = hsi_get_port(cl);
670
671 if (!handler || cl->ehandler)
672 return -EINVAL;
673 if (!hsi_port_claimed(cl))
674 return -EACCES;
675 cl->ehandler = handler;
676 cl->nb.notifier_call = hsi_event_notifier_call;
677
678 return blocking_notifier_chain_register(nh: &port->n_head, nb: &cl->nb);
679}
680EXPORT_SYMBOL_GPL(hsi_register_port_event);
681
682/**
683 * hsi_unregister_port_event - Stop receiving port events for a client
684 * @cl: HSI client that wants to stop receiving port events
685 *
686 * Clients should call this function before releasing their associated
687 * port.
688 *
689 * Returns -errno on error, or 0 on success.
690 */
691int hsi_unregister_port_event(struct hsi_client *cl)
692{
693 struct hsi_port *port = hsi_get_port(cl);
694 int err;
695
696 WARN_ON(!hsi_port_claimed(cl));
697
698 err = blocking_notifier_chain_unregister(nh: &port->n_head, nb: &cl->nb);
699 if (!err)
700 cl->ehandler = NULL;
701
702 return err;
703}
704EXPORT_SYMBOL_GPL(hsi_unregister_port_event);
705
706/**
707 * hsi_event - Notifies clients about port events
708 * @port: Port where the event occurred
709 * @event: The event type
710 *
711 * Clients should not be concerned about wake line behavior. However, due
712 * to a race condition in HSI HW protocol, clients need to be notified
713 * about wake line changes, so they can implement a workaround for it.
714 *
715 * Events:
716 * HSI_EVENT_START_RX - Incoming wake line high
717 * HSI_EVENT_STOP_RX - Incoming wake line down
718 *
719 * Returns -errno on error, or 0 on success.
720 */
721int hsi_event(struct hsi_port *port, unsigned long event)
722{
723 return blocking_notifier_call_chain(nh: &port->n_head, val: event, NULL);
724}
725EXPORT_SYMBOL_GPL(hsi_event);
726
727/**
728 * hsi_get_channel_id_by_name - acquire channel id by channel name
729 * @cl: HSI client, which uses the channel
730 * @name: name the channel is known under
731 *
732 * Clients can call this function to get the hsi channel ids similar to
733 * requesting IRQs or GPIOs by name. This function assumes the same
734 * channel configuration is used for RX and TX.
735 *
736 * Returns -errno on error or channel id on success.
737 */
738int hsi_get_channel_id_by_name(struct hsi_client *cl, char *name)
739{
740 int i;
741
742 if (!cl->rx_cfg.channels)
743 return -ENOENT;
744
745 for (i = 0; i < cl->rx_cfg.num_channels; i++)
746 if (!strcmp(cl->rx_cfg.channels[i].name, name))
747 return cl->rx_cfg.channels[i].id;
748
749 return -ENXIO;
750}
751EXPORT_SYMBOL_GPL(hsi_get_channel_id_by_name);
752
753static int __init hsi_init(void)
754{
755 return bus_register(bus: &hsi_bus_type);
756}
757postcore_initcall(hsi_init);
758
759static void __exit hsi_exit(void)
760{
761 bus_unregister(bus: &hsi_bus_type);
762}
763module_exit(hsi_exit);
764
765MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
766MODULE_DESCRIPTION("High-speed Synchronous Serial Interface (HSI) framework");
767MODULE_LICENSE("GPL v2");
768

source code of linux/drivers/hsi/hsi_core.c