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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * core.c - Implementation of core module of MOST Linux driver stack
4 *
5 * Copyright (C) 2013-2020 Microchip Technology Germany II GmbH & Co. KG
6 */
7
8#include <linux/module.h>
9#include <linux/fs.h>
10#include <linux/slab.h>
11#include <linux/init.h>
12#include <linux/device.h>
13#include <linux/list.h>
14#include <linux/poll.h>
15#include <linux/wait.h>
16#include <linux/kobject.h>
17#include <linux/mutex.h>
18#include <linux/completion.h>
19#include <linux/sysfs.h>
20#include <linux/kthread.h>
21#include <linux/dma-mapping.h>
22#include <linux/idr.h>
23#include <linux/most.h>
24
25#define MAX_CHANNELS 64
26#define STRING_SIZE 80
27
28static struct ida mdev_id;
29static int dummy_num_buffers;
30static struct list_head comp_list;
31
32struct pipe {
33 struct most_component *comp;
34 int refs;
35 int num_buffers;
36};
37
38struct most_channel {
39 struct device dev;
40 struct completion cleanup;
41 atomic_t mbo_ref;
42 atomic_t mbo_nq_level;
43 u16 channel_id;
44 char name[STRING_SIZE];
45 bool is_poisoned;
46 struct mutex start_mutex; /* channel activation synchronization */
47 struct mutex nq_mutex; /* nq thread synchronization */
48 int is_starving;
49 struct most_interface *iface;
50 struct most_channel_config cfg;
51 bool keep_mbo;
52 bool enqueue_halt;
53 struct list_head fifo;
54 spinlock_t fifo_lock; /* fifo access synchronization */
55 struct list_head halt_fifo;
56 struct list_head list;
57 struct pipe pipe0;
58 struct pipe pipe1;
59 struct list_head trash_fifo;
60 struct task_struct *hdm_enqueue_task;
61 wait_queue_head_t hdm_fifo_wq;
62
63};
64
65#define to_channel(d) container_of(d, struct most_channel, dev)
66
67struct interface_private {
68 int dev_id;
69 char name[STRING_SIZE];
70 struct most_channel *channel[MAX_CHANNELS];
71 struct list_head channel_list;
72};
73
74static const struct {
75 int most_ch_data_type;
76 const char *name;
77} ch_data_type[] = {
78 { MOST_CH_CONTROL, "control" },
79 { MOST_CH_ASYNC, "async" },
80 { MOST_CH_SYNC, "sync" },
81 { MOST_CH_ISOC, "isoc"},
82 { MOST_CH_ISOC, "isoc_avp"},
83};
84
85/**
86 * list_pop_mbo - retrieves the first MBO of the list and removes it
87 * @ptr: the list head to grab the MBO from.
88 */
89#define list_pop_mbo(ptr) \
90({ \
91 struct mbo *_mbo = list_first_entry(ptr, struct mbo, list); \
92 list_del(&_mbo->list); \
93 _mbo; \
94})
95
96/**
97 * most_free_mbo_coherent - free an MBO and its coherent buffer
98 * @mbo: most buffer
99 */
100static void most_free_mbo_coherent(struct mbo *mbo)
101{
102 struct most_channel *c = mbo->context;
103 u16 const coherent_buf_size = c->cfg.buffer_size + c->cfg.extra_len;
104
105 if (c->iface->dma_free)
106 c->iface->dma_free(mbo, coherent_buf_size);
107 else
108 kfree(mbo->virt_address);
109 kfree(mbo);
110 if (atomic_sub_and_test(1, &c->mbo_ref))
111 complete(&c->cleanup);
112}
113
114/**
115 * flush_channel_fifos - clear the channel fifos
116 * @c: pointer to channel object
117 */
118static void flush_channel_fifos(struct most_channel *c)
119{
120 unsigned long flags, hf_flags;
121 struct mbo *mbo, *tmp;
122
123 if (list_empty(&c->fifo) && list_empty(&c->halt_fifo))
124 return;
125
126 spin_lock_irqsave(&c->fifo_lock, flags);
127 list_for_each_entry_safe(mbo, tmp, &c->fifo, list) {
128 list_del(&mbo->list);
129 spin_unlock_irqrestore(&c->fifo_lock, flags);
130 most_free_mbo_coherent(mbo);
131 spin_lock_irqsave(&c->fifo_lock, flags);
132 }
133 spin_unlock_irqrestore(&c->fifo_lock, flags);
134
135 spin_lock_irqsave(&c->fifo_lock, hf_flags);
136 list_for_each_entry_safe(mbo, tmp, &c->halt_fifo, list) {
137 list_del(&mbo->list);
138 spin_unlock_irqrestore(&c->fifo_lock, hf_flags);
139 most_free_mbo_coherent(mbo);
140 spin_lock_irqsave(&c->fifo_lock, hf_flags);
141 }
142 spin_unlock_irqrestore(&c->fifo_lock, hf_flags);
143
144 if (unlikely((!list_empty(&c->fifo) || !list_empty(&c->halt_fifo))))
145 dev_warn(&c->dev, "Channel or trash fifo not empty\n");
146}
147
148/**
149 * flush_trash_fifo - clear the trash fifo
150 * @c: pointer to channel object
151 */
152static int flush_trash_fifo(struct most_channel *c)
153{
154 struct mbo *mbo, *tmp;
155 unsigned long flags;
156
157 spin_lock_irqsave(&c->fifo_lock, flags);
158 list_for_each_entry_safe(mbo, tmp, &c->trash_fifo, list) {
159 list_del(&mbo->list);
160 spin_unlock_irqrestore(&c->fifo_lock, flags);
161 most_free_mbo_coherent(mbo);
162 spin_lock_irqsave(&c->fifo_lock, flags);
163 }
164 spin_unlock_irqrestore(&c->fifo_lock, flags);
165 return 0;
166}
167
168static ssize_t available_directions_show(struct device *dev,
169 struct device_attribute *attr,
170 char *buf)
171{
172 struct most_channel *c = to_channel(dev);
173 unsigned int i = c->channel_id;
174
175 strcpy(buf, "");
176 if (c->iface->channel_vector[i].direction & MOST_CH_RX)
177 strcat(buf, "rx ");
178 if (c->iface->channel_vector[i].direction & MOST_CH_TX)
179 strcat(buf, "tx ");
180 strcat(buf, "\n");
181 return strlen(buf);
182}
183
184static ssize_t available_datatypes_show(struct device *dev,
185 struct device_attribute *attr,
186 char *buf)
187{
188 struct most_channel *c = to_channel(dev);
189 unsigned int i = c->channel_id;
190
191 strcpy(buf, "");
192 if (c->iface->channel_vector[i].data_type & MOST_CH_CONTROL)
193 strcat(buf, "control ");
194 if (c->iface->channel_vector[i].data_type & MOST_CH_ASYNC)
195 strcat(buf, "async ");
196 if (c->iface->channel_vector[i].data_type & MOST_CH_SYNC)
197 strcat(buf, "sync ");
198 if (c->iface->channel_vector[i].data_type & MOST_CH_ISOC)
199 strcat(buf, "isoc ");
200 strcat(buf, "\n");
201 return strlen(buf);
202}
203
204static ssize_t number_of_packet_buffers_show(struct device *dev,
205 struct device_attribute *attr,
206 char *buf)
207{
208 struct most_channel *c = to_channel(dev);
209 unsigned int i = c->channel_id;
210
211 return snprintf(buf, PAGE_SIZE, "%d\n",
212 c->iface->channel_vector[i].num_buffers_packet);
213}
214
215static ssize_t number_of_stream_buffers_show(struct device *dev,
216 struct device_attribute *attr,
217 char *buf)
218{
219 struct most_channel *c = to_channel(dev);
220 unsigned int i = c->channel_id;
221
222 return snprintf(buf, PAGE_SIZE, "%d\n",
223 c->iface->channel_vector[i].num_buffers_streaming);
224}
225
226static ssize_t size_of_packet_buffer_show(struct device *dev,
227 struct device_attribute *attr,
228 char *buf)
229{
230 struct most_channel *c = to_channel(dev);
231 unsigned int i = c->channel_id;
232
233 return snprintf(buf, PAGE_SIZE, "%d\n",
234 c->iface->channel_vector[i].buffer_size_packet);
235}
236
237static ssize_t size_of_stream_buffer_show(struct device *dev,
238 struct device_attribute *attr,
239 char *buf)
240{
241 struct most_channel *c = to_channel(dev);
242 unsigned int i = c->channel_id;
243
244 return snprintf(buf, PAGE_SIZE, "%d\n",
245 c->iface->channel_vector[i].buffer_size_streaming);
246}
247
248static ssize_t channel_starving_show(struct device *dev,
249 struct device_attribute *attr,
250 char *buf)
251{
252 struct most_channel *c = to_channel(dev);
253
254 return snprintf(buf, PAGE_SIZE, "%d\n", c->is_starving);
255}
256
257static ssize_t set_number_of_buffers_show(struct device *dev,
258 struct device_attribute *attr,
259 char *buf)
260{
261 struct most_channel *c = to_channel(dev);
262
263 return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.num_buffers);
264}
265
266static ssize_t set_buffer_size_show(struct device *dev,
267 struct device_attribute *attr,
268 char *buf)
269{
270 struct most_channel *c = to_channel(dev);
271
272 return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.buffer_size);
273}
274
275static ssize_t set_direction_show(struct device *dev,
276 struct device_attribute *attr,
277 char *buf)
278{
279 struct most_channel *c = to_channel(dev);
280
281 if (c->cfg.direction & MOST_CH_TX)
282 return snprintf(buf, PAGE_SIZE, "tx\n");
283 else if (c->cfg.direction & MOST_CH_RX)
284 return snprintf(buf, PAGE_SIZE, "rx\n");
285 return snprintf(buf, PAGE_SIZE, "unconfigured\n");
286}
287
288static ssize_t set_datatype_show(struct device *dev,
289 struct device_attribute *attr,
290 char *buf)
291{
292 int i;
293 struct most_channel *c = to_channel(dev);
294
295 for (i = 0; i < ARRAY_SIZE(ch_data_type); i++) {
296 if (c->cfg.data_type & ch_data_type[i].most_ch_data_type)
297 return snprintf(buf, PAGE_SIZE, "%s",
298 ch_data_type[i].name);
299 }
300 return snprintf(buf, PAGE_SIZE, "unconfigured\n");
301}
302
303static ssize_t set_subbuffer_size_show(struct device *dev,
304 struct device_attribute *attr,
305 char *buf)
306{
307 struct most_channel *c = to_channel(dev);
308
309 return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.subbuffer_size);
310}
311
312static ssize_t set_packets_per_xact_show(struct device *dev,
313 struct device_attribute *attr,
314 char *buf)
315{
316 struct most_channel *c = to_channel(dev);
317
318 return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.packets_per_xact);
319}
320
321static ssize_t set_dbr_size_show(struct device *dev,
322 struct device_attribute *attr, char *buf)
323{
324 struct most_channel *c = to_channel(dev);
325
326 return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.dbr_size);
327}
328
329#define to_dev_attr(a) container_of(a, struct device_attribute, attr)
330static umode_t channel_attr_is_visible(struct kobject *kobj,
331 struct attribute *attr, int index)
332{
333 struct device_attribute *dev_attr = to_dev_attr(attr);
334 struct device *dev = kobj_to_dev(kobj);
335 struct most_channel *c = to_channel(dev);
336
337 if (!strcmp(dev_attr->attr.name, "set_dbr_size") &&
338 (c->iface->interface != ITYPE_MEDIALB_DIM2))
339 return 0;
340 if (!strcmp(dev_attr->attr.name, "set_packets_per_xact") &&
341 (c->iface->interface != ITYPE_USB))
342 return 0;
343
344 return attr->mode;
345}
346
347#define DEV_ATTR(_name) (&dev_attr_##_name.attr)
348
349static DEVICE_ATTR_RO(available_directions);
350static DEVICE_ATTR_RO(available_datatypes);
351static DEVICE_ATTR_RO(number_of_packet_buffers);
352static DEVICE_ATTR_RO(number_of_stream_buffers);
353static DEVICE_ATTR_RO(size_of_stream_buffer);
354static DEVICE_ATTR_RO(size_of_packet_buffer);
355static DEVICE_ATTR_RO(channel_starving);
356static DEVICE_ATTR_RO(set_buffer_size);
357static DEVICE_ATTR_RO(set_number_of_buffers);
358static DEVICE_ATTR_RO(set_direction);
359static DEVICE_ATTR_RO(set_datatype);
360static DEVICE_ATTR_RO(set_subbuffer_size);
361static DEVICE_ATTR_RO(set_packets_per_xact);
362static DEVICE_ATTR_RO(set_dbr_size);
363
364static struct attribute *channel_attrs[] = {
365 DEV_ATTR(available_directions),
366 DEV_ATTR(available_datatypes),
367 DEV_ATTR(number_of_packet_buffers),
368 DEV_ATTR(number_of_stream_buffers),
369 DEV_ATTR(size_of_stream_buffer),
370 DEV_ATTR(size_of_packet_buffer),
371 DEV_ATTR(channel_starving),
372 DEV_ATTR(set_buffer_size),
373 DEV_ATTR(set_number_of_buffers),
374 DEV_ATTR(set_direction),
375 DEV_ATTR(set_datatype),
376 DEV_ATTR(set_subbuffer_size),
377 DEV_ATTR(set_packets_per_xact),
378 DEV_ATTR(set_dbr_size),
379 NULL,
380};
381
382static const struct attribute_group channel_attr_group = {
383 .attrs = channel_attrs,
384 .is_visible = channel_attr_is_visible,
385};
386
387static const struct attribute_group *channel_attr_groups[] = {
388 &channel_attr_group,
389 NULL,
390};
391
392static ssize_t description_show(struct device *dev,
393 struct device_attribute *attr,
394 char *buf)
395{
396 struct most_interface *iface = dev_get_drvdata(dev);
397
398 return snprintf(buf, PAGE_SIZE, "%s\n", iface->description);
399}
400
401static ssize_t interface_show(struct device *dev,
402 struct device_attribute *attr,
403 char *buf)
404{
405 struct most_interface *iface = dev_get_drvdata(dev);
406
407 switch (iface->interface) {
408 case ITYPE_LOOPBACK:
409 return snprintf(buf, PAGE_SIZE, "loopback\n");
410 case ITYPE_I2C:
411 return snprintf(buf, PAGE_SIZE, "i2c\n");
412 case ITYPE_I2S:
413 return snprintf(buf, PAGE_SIZE, "i2s\n");
414 case ITYPE_TSI:
415 return snprintf(buf, PAGE_SIZE, "tsi\n");
416 case ITYPE_HBI:
417 return snprintf(buf, PAGE_SIZE, "hbi\n");
418 case ITYPE_MEDIALB_DIM:
419 return snprintf(buf, PAGE_SIZE, "mlb_dim\n");
420 case ITYPE_MEDIALB_DIM2:
421 return snprintf(buf, PAGE_SIZE, "mlb_dim2\n");
422 case ITYPE_USB:
423 return snprintf(buf, PAGE_SIZE, "usb\n");
424 case ITYPE_PCIE:
425 return snprintf(buf, PAGE_SIZE, "pcie\n");
426 }
427 return snprintf(buf, PAGE_SIZE, "unknown\n");
428}
429
430static DEVICE_ATTR_RO(description);
431static DEVICE_ATTR_RO(interface);
432
433static struct attribute *interface_attrs[] = {
434 DEV_ATTR(description),
435 DEV_ATTR(interface),
436 NULL,
437};
438
439static const struct attribute_group interface_attr_group = {
440 .attrs = interface_attrs,
441};
442
443static const struct attribute_group *interface_attr_groups[] = {
444 &interface_attr_group,
445 NULL,
446};
447
448static struct most_component *match_component(char *name)
449{
450 struct most_component *comp;
451
452 list_for_each_entry(comp, &comp_list, list) {
453 if (!strcmp(comp->name, name))
454 return comp;
455 }
456 return NULL;
457}
458
459struct show_links_data {
460 int offs;
461 char *buf;
462};
463
464static int print_links(struct device *dev, void *data)
465{
466 struct show_links_data *d = data;
467 int offs = d->offs;
468 char *buf = d->buf;
469 struct most_channel *c;
470 struct most_interface *iface = dev_get_drvdata(dev);
471
472 list_for_each_entry(c, &iface->p->channel_list, list) {
473 if (c->pipe0.comp) {
474 offs += scnprintf(buf + offs,
475 PAGE_SIZE - offs,
476 "%s:%s:%s\n",
477 c->pipe0.comp->name,
478 dev_name(iface->dev),
479 dev_name(&c->dev));
480 }
481 if (c->pipe1.comp) {
482 offs += scnprintf(buf + offs,
483 PAGE_SIZE - offs,
484 "%s:%s:%s\n",
485 c->pipe1.comp->name,
486 dev_name(iface->dev),
487 dev_name(&c->dev));
488 }
489 }
490 d->offs = offs;
491 return 0;
492}
493
494static int most_match(struct device *dev, const struct device_driver *drv)
495{
496 if (!strcmp(dev_name(dev), "most"))
497 return 0;
498 else
499 return 1;
500}
501
502static const struct bus_type mostbus = {
503 .name = "most",
504 .match = most_match,
505};
506
507static ssize_t links_show(struct device_driver *drv, char *buf)
508{
509 struct show_links_data d = { .buf = buf };
510
511 bus_for_each_dev(&mostbus, NULL, &d, print_links);
512 return d.offs;
513}
514
515static ssize_t components_show(struct device_driver *drv, char *buf)
516{
517 struct most_component *comp;
518 int offs = 0;
519
520 list_for_each_entry(comp, &comp_list, list) {
521 offs += scnprintf(buf + offs, PAGE_SIZE - offs, "%s\n",
522 comp->name);
523 }
524 return offs;
525}
526
527/**
528 * get_channel - get pointer to channel
529 * @mdev: name of the device interface
530 * @mdev_ch: name of channel
531 */
532static struct most_channel *get_channel(char *mdev, char *mdev_ch)
533{
534 struct device *dev = NULL;
535 struct most_interface *iface;
536 struct most_channel *c, *tmp;
537
538 dev = bus_find_device_by_name(&mostbus, NULL, mdev);
539 if (!dev)
540 return NULL;
541 iface = dev_get_drvdata(dev);
542 put_device(dev);
543 list_for_each_entry_safe(c, tmp, &iface->p->channel_list, list) {
544 if (!strcmp(dev_name(&c->dev), mdev_ch))
545 return c;
546 }
547 return NULL;
548}
549
550static
551inline int link_channel_to_component(struct most_channel *c,
552 struct most_component *comp,
553 char *name,
554 char *comp_param)
555{
556 int ret;
557 struct most_component **comp_ptr;
558
559 if (!c->pipe0.comp)
560 comp_ptr = &c->pipe0.comp;
561 else if (!c->pipe1.comp)
562 comp_ptr = &c->pipe1.comp;
563 else
564 return -ENOSPC;
565
566 *comp_ptr = comp;
567 ret = comp->probe_channel(c->iface, c->channel_id, &c->cfg, name,
568 comp_param);
569 if (ret) {
570 *comp_ptr = NULL;
571 return ret;
572 }
573 return 0;
574}
575
576int most_set_cfg_buffer_size(char *mdev, char *mdev_ch, u16 val)
577{
578 struct most_channel *c = get_channel(mdev, mdev_ch);
579
580 if (!c)
581 return -ENODEV;
582 c->cfg.buffer_size = val;
583 return 0;
584}
585
586int most_set_cfg_subbuffer_size(char *mdev, char *mdev_ch, u16 val)
587{
588 struct most_channel *c = get_channel(mdev, mdev_ch);
589
590 if (!c)
591 return -ENODEV;
592 c->cfg.subbuffer_size = val;
593 return 0;
594}
595
596int most_set_cfg_dbr_size(char *mdev, char *mdev_ch, u16 val)
597{
598 struct most_channel *c = get_channel(mdev, mdev_ch);
599
600 if (!c)
601 return -ENODEV;
602 c->cfg.dbr_size = val;
603 return 0;
604}
605
606int most_set_cfg_num_buffers(char *mdev, char *mdev_ch, u16 val)
607{
608 struct most_channel *c = get_channel(mdev, mdev_ch);
609
610 if (!c)
611 return -ENODEV;
612 c->cfg.num_buffers = val;
613 return 0;
614}
615
616int most_set_cfg_datatype(char *mdev, char *mdev_ch, char *buf)
617{
618 int i;
619 struct most_channel *c = get_channel(mdev, mdev_ch);
620
621 if (!c)
622 return -ENODEV;
623 for (i = 0; i < ARRAY_SIZE(ch_data_type); i++) {
624 if (!strcmp(buf, ch_data_type[i].name)) {
625 c->cfg.data_type = ch_data_type[i].most_ch_data_type;
626 break;
627 }
628 }
629
630 if (i == ARRAY_SIZE(ch_data_type))
631 dev_warn(&c->dev, "Invalid attribute settings\n");
632 return 0;
633}
634
635int most_set_cfg_direction(char *mdev, char *mdev_ch, char *buf)
636{
637 struct most_channel *c = get_channel(mdev, mdev_ch);
638
639 if (!c)
640 return -ENODEV;
641 if (!strcmp(buf, "dir_rx")) {
642 c->cfg.direction = MOST_CH_RX;
643 } else if (!strcmp(buf, "rx")) {
644 c->cfg.direction = MOST_CH_RX;
645 } else if (!strcmp(buf, "dir_tx")) {
646 c->cfg.direction = MOST_CH_TX;
647 } else if (!strcmp(buf, "tx")) {
648 c->cfg.direction = MOST_CH_TX;
649 } else {
650 dev_err(&c->dev, "Invalid direction\n");
651 return -ENODATA;
652 }
653 return 0;
654}
655
656int most_set_cfg_packets_xact(char *mdev, char *mdev_ch, u16 val)
657{
658 struct most_channel *c = get_channel(mdev, mdev_ch);
659
660 if (!c)
661 return -ENODEV;
662 c->cfg.packets_per_xact = val;
663 return 0;
664}
665
666int most_cfg_complete(char *comp_name)
667{
668 struct most_component *comp;
669
670 comp = match_component(comp_name);
671 if (!comp)
672 return -ENODEV;
673
674 return comp->cfg_complete();
675}
676
677int most_add_link(char *mdev, char *mdev_ch, char *comp_name, char *link_name,
678 char *comp_param)
679{
680 struct most_channel *c = get_channel(mdev, mdev_ch);
681 struct most_component *comp = match_component(comp_name);
682
683 if (!c || !comp)
684 return -ENODEV;
685
686 return link_channel_to_component(c, comp, link_name, comp_param);
687}
688
689int most_remove_link(char *mdev, char *mdev_ch, char *comp_name)
690{
691 struct most_channel *c;
692 struct most_component *comp;
693
694 comp = match_component(comp_name);
695 if (!comp)
696 return -ENODEV;
697 c = get_channel(mdev, mdev_ch);
698 if (!c)
699 return -ENODEV;
700
701 if (comp->disconnect_channel(c->iface, c->channel_id))
702 return -EIO;
703 if (c->pipe0.comp == comp)
704 c->pipe0.comp = NULL;
705 if (c->pipe1.comp == comp)
706 c->pipe1.comp = NULL;
707 return 0;
708}
709
710#define DRV_ATTR(_name) (&driver_attr_##_name.attr)
711
712static DRIVER_ATTR_RO(links);
713static DRIVER_ATTR_RO(components);
714
715static struct attribute *mc_attrs[] = {
716 DRV_ATTR(links),
717 DRV_ATTR(components),
718 NULL,
719};
720
721static const struct attribute_group mc_attr_group = {
722 .attrs = mc_attrs,
723};
724
725static const struct attribute_group *mc_attr_groups[] = {
726 &mc_attr_group,
727 NULL,
728};
729
730static struct device_driver mostbus_driver = {
731 .name = "most_core",
732 .bus = &mostbus,
733 .groups = mc_attr_groups,
734};
735
736static inline void trash_mbo(struct mbo *mbo)
737{
738 unsigned long flags;
739 struct most_channel *c = mbo->context;
740
741 spin_lock_irqsave(&c->fifo_lock, flags);
742 list_add(&mbo->list, &c->trash_fifo);
743 spin_unlock_irqrestore(&c->fifo_lock, flags);
744}
745
746static bool hdm_mbo_ready(struct most_channel *c)
747{
748 bool empty;
749
750 if (c->enqueue_halt)
751 return false;
752
753 spin_lock_irq(&c->fifo_lock);
754 empty = list_empty(&c->halt_fifo);
755 spin_unlock_irq(&c->fifo_lock);
756
757 return !empty;
758}
759
760static void nq_hdm_mbo(struct mbo *mbo)
761{
762 unsigned long flags;
763 struct most_channel *c = mbo->context;
764
765 spin_lock_irqsave(&c->fifo_lock, flags);
766 list_add_tail(&mbo->list, &c->halt_fifo);
767 spin_unlock_irqrestore(&c->fifo_lock, flags);
768 wake_up_interruptible(&c->hdm_fifo_wq);
769}
770
771static int hdm_enqueue_thread(void *data)
772{
773 struct most_channel *c = data;
774 struct mbo *mbo;
775 int ret;
776 typeof(c->iface->enqueue) enqueue = c->iface->enqueue;
777
778 while (likely(!kthread_should_stop())) {
779 wait_event_interruptible(c->hdm_fifo_wq,
780 hdm_mbo_ready(c) ||
781 kthread_should_stop());
782
783 mutex_lock(&c->nq_mutex);
784 spin_lock_irq(&c->fifo_lock);
785 if (unlikely(c->enqueue_halt || list_empty(&c->halt_fifo))) {
786 spin_unlock_irq(&c->fifo_lock);
787 mutex_unlock(&c->nq_mutex);
788 continue;
789 }
790
791 mbo = list_pop_mbo(&c->halt_fifo);
792 spin_unlock_irq(&c->fifo_lock);
793
794 if (c->cfg.direction == MOST_CH_RX)
795 mbo->buffer_length = c->cfg.buffer_size;
796
797 ret = enqueue(mbo->ifp, mbo->hdm_channel_id, mbo);
798 mutex_unlock(&c->nq_mutex);
799
800 if (unlikely(ret)) {
801 dev_err(&c->dev, "Buffer enqueue failed\n");
802 nq_hdm_mbo(mbo);
803 c->hdm_enqueue_task = NULL;
804 return 0;
805 }
806 }
807
808 return 0;
809}
810
811static int run_enqueue_thread(struct most_channel *c, int channel_id)
812{
813 struct task_struct *task =
814 kthread_run(hdm_enqueue_thread, c, "hdm_fifo_%d",
815 channel_id);
816
817 if (IS_ERR(task))
818 return PTR_ERR(task);
819
820 c->hdm_enqueue_task = task;
821 return 0;
822}
823
824/**
825 * arm_mbo - recycle MBO for further usage
826 * @mbo: most buffer
827 *
828 * This puts an MBO back to the list to have it ready for up coming
829 * tx transactions.
830 *
831 * In case the MBO belongs to a channel that recently has been
832 * poisoned, the MBO is scheduled to be trashed.
833 * Calls the completion handler of an attached component.
834 */
835static void arm_mbo(struct mbo *mbo)
836{
837 unsigned long flags;
838 struct most_channel *c;
839
840 c = mbo->context;
841
842 if (c->is_poisoned) {
843 trash_mbo(mbo);
844 return;
845 }
846
847 spin_lock_irqsave(&c->fifo_lock, flags);
848 ++*mbo->num_buffers_ptr;
849 list_add_tail(&mbo->list, &c->fifo);
850 spin_unlock_irqrestore(&c->fifo_lock, flags);
851
852 if (c->pipe0.refs && c->pipe0.comp->tx_completion)
853 c->pipe0.comp->tx_completion(c->iface, c->channel_id);
854
855 if (c->pipe1.refs && c->pipe1.comp->tx_completion)
856 c->pipe1.comp->tx_completion(c->iface, c->channel_id);
857}
858
859/**
860 * arm_mbo_chain - helper function that arms an MBO chain for the HDM
861 * @c: pointer to interface channel
862 * @dir: direction of the channel
863 * @compl: pointer to completion function
864 *
865 * This allocates buffer objects including the containing DMA coherent
866 * buffer and puts them in the fifo.
867 * Buffers of Rx channels are put in the kthread fifo, hence immediately
868 * submitted to the HDM.
869 *
870 * Returns the number of allocated and enqueued MBOs.
871 */
872static int arm_mbo_chain(struct most_channel *c, int dir,
873 void (*compl)(struct mbo *))
874{
875 unsigned int i;
876 struct mbo *mbo;
877 unsigned long flags;
878 u32 coherent_buf_size = c->cfg.buffer_size + c->cfg.extra_len;
879
880 atomic_set(&c->mbo_nq_level, 0);
881
882 for (i = 0; i < c->cfg.num_buffers; i++) {
883 mbo = kzalloc_obj(*mbo);
884 if (!mbo)
885 goto flush_fifos;
886
887 mbo->context = c;
888 mbo->ifp = c->iface;
889 mbo->hdm_channel_id = c->channel_id;
890 if (c->iface->dma_alloc) {
891 mbo->virt_address =
892 c->iface->dma_alloc(mbo, coherent_buf_size);
893 } else {
894 mbo->virt_address =
895 kzalloc(coherent_buf_size, GFP_KERNEL);
896 }
897 if (!mbo->virt_address)
898 goto release_mbo;
899
900 mbo->complete = compl;
901 mbo->num_buffers_ptr = &dummy_num_buffers;
902 if (dir == MOST_CH_RX) {
903 nq_hdm_mbo(mbo);
904 atomic_inc(&c->mbo_nq_level);
905 } else {
906 spin_lock_irqsave(&c->fifo_lock, flags);
907 list_add_tail(&mbo->list, &c->fifo);
908 spin_unlock_irqrestore(&c->fifo_lock, flags);
909 }
910 }
911 return c->cfg.num_buffers;
912
913release_mbo:
914 kfree(mbo);
915
916flush_fifos:
917 flush_channel_fifos(c);
918 return 0;
919}
920
921/**
922 * most_submit_mbo - submits an MBO to fifo
923 * @mbo: most buffer
924 */
925void most_submit_mbo(struct mbo *mbo)
926{
927 if (WARN_ONCE(!mbo || !mbo->context,
928 "Bad buffer or missing channel reference\n"))
929 return;
930
931 nq_hdm_mbo(mbo);
932}
933EXPORT_SYMBOL_GPL(most_submit_mbo);
934
935/**
936 * most_write_completion - write completion handler
937 * @mbo: most buffer
938 *
939 * This recycles the MBO for further usage. In case the channel has been
940 * poisoned, the MBO is scheduled to be trashed.
941 */
942static void most_write_completion(struct mbo *mbo)
943{
944 struct most_channel *c;
945
946 c = mbo->context;
947 if (unlikely(c->is_poisoned || (mbo->status == MBO_E_CLOSE)))
948 trash_mbo(mbo);
949 else
950 arm_mbo(mbo);
951}
952
953int channel_has_mbo(struct most_interface *iface, int id,
954 struct most_component *comp)
955{
956 struct most_channel *c = iface->p->channel[id];
957 unsigned long flags;
958 int empty;
959
960 if (unlikely(!c))
961 return -EINVAL;
962
963 if (c->pipe0.refs && c->pipe1.refs &&
964 ((comp == c->pipe0.comp && c->pipe0.num_buffers <= 0) ||
965 (comp == c->pipe1.comp && c->pipe1.num_buffers <= 0)))
966 return 0;
967
968 spin_lock_irqsave(&c->fifo_lock, flags);
969 empty = list_empty(&c->fifo);
970 spin_unlock_irqrestore(&c->fifo_lock, flags);
971 return !empty;
972}
973EXPORT_SYMBOL_GPL(channel_has_mbo);
974
975/**
976 * most_get_mbo - get pointer to an MBO of pool
977 * @iface: pointer to interface instance
978 * @id: channel ID
979 * @comp: driver component
980 *
981 * This attempts to get a free buffer out of the channel fifo.
982 * Returns a pointer to MBO on success or NULL otherwise.
983 */
984struct mbo *most_get_mbo(struct most_interface *iface, int id,
985 struct most_component *comp)
986{
987 struct mbo *mbo;
988 struct most_channel *c;
989 unsigned long flags;
990 int *num_buffers_ptr;
991
992 c = iface->p->channel[id];
993 if (unlikely(!c))
994 return NULL;
995
996 if (c->pipe0.refs && c->pipe1.refs &&
997 ((comp == c->pipe0.comp && c->pipe0.num_buffers <= 0) ||
998 (comp == c->pipe1.comp && c->pipe1.num_buffers <= 0)))
999 return NULL;
1000
1001 if (comp == c->pipe0.comp)
1002 num_buffers_ptr = &c->pipe0.num_buffers;
1003 else if (comp == c->pipe1.comp)
1004 num_buffers_ptr = &c->pipe1.num_buffers;
1005 else
1006 num_buffers_ptr = &dummy_num_buffers;
1007
1008 spin_lock_irqsave(&c->fifo_lock, flags);
1009 if (list_empty(&c->fifo)) {
1010 spin_unlock_irqrestore(&c->fifo_lock, flags);
1011 return NULL;
1012 }
1013 mbo = list_pop_mbo(&c->fifo);
1014 --*num_buffers_ptr;
1015 spin_unlock_irqrestore(&c->fifo_lock, flags);
1016
1017 mbo->num_buffers_ptr = num_buffers_ptr;
1018 mbo->buffer_length = c->cfg.buffer_size;
1019 return mbo;
1020}
1021EXPORT_SYMBOL_GPL(most_get_mbo);
1022
1023/**
1024 * most_put_mbo - return buffer to pool
1025 * @mbo: most buffer
1026 */
1027void most_put_mbo(struct mbo *mbo)
1028{
1029 struct most_channel *c = mbo->context;
1030
1031 if (c->cfg.direction == MOST_CH_TX) {
1032 arm_mbo(mbo);
1033 return;
1034 }
1035 nq_hdm_mbo(mbo);
1036 atomic_inc(&c->mbo_nq_level);
1037}
1038EXPORT_SYMBOL_GPL(most_put_mbo);
1039
1040/**
1041 * most_read_completion - read completion handler
1042 * @mbo: most buffer
1043 *
1044 * This function is called by the HDM when data has been received from the
1045 * hardware and copied to the buffer of the MBO.
1046 *
1047 * In case the channel has been poisoned it puts the buffer in the trash queue.
1048 * Otherwise, it passes the buffer to an component for further processing.
1049 */
1050static void most_read_completion(struct mbo *mbo)
1051{
1052 struct most_channel *c = mbo->context;
1053
1054 if (unlikely(c->is_poisoned || (mbo->status == MBO_E_CLOSE))) {
1055 trash_mbo(mbo);
1056 return;
1057 }
1058
1059 if (mbo->status == MBO_E_INVAL) {
1060 nq_hdm_mbo(mbo);
1061 atomic_inc(&c->mbo_nq_level);
1062 return;
1063 }
1064
1065 if (atomic_sub_and_test(1, &c->mbo_nq_level))
1066 c->is_starving = 1;
1067
1068 if (c->pipe0.refs && c->pipe0.comp->rx_completion &&
1069 c->pipe0.comp->rx_completion(mbo) == 0)
1070 return;
1071
1072 if (c->pipe1.refs && c->pipe1.comp->rx_completion &&
1073 c->pipe1.comp->rx_completion(mbo) == 0)
1074 return;
1075
1076 most_put_mbo(mbo);
1077}
1078
1079/**
1080 * most_start_channel - prepares a channel for communication
1081 * @iface: pointer to interface instance
1082 * @id: channel ID
1083 * @comp: driver component
1084 *
1085 * This prepares the channel for usage. Cross-checks whether the
1086 * channel's been properly configured.
1087 *
1088 * Returns 0 on success or error code otherwise.
1089 */
1090int most_start_channel(struct most_interface *iface, int id,
1091 struct most_component *comp)
1092{
1093 int num_buffer;
1094 int ret;
1095 struct most_channel *c = iface->p->channel[id];
1096
1097 if (unlikely(!c))
1098 return -EINVAL;
1099
1100 mutex_lock(&c->start_mutex);
1101 if (c->pipe0.refs + c->pipe1.refs > 0)
1102 goto out; /* already started by another component */
1103
1104 if (!try_module_get(iface->mod)) {
1105 dev_err(&c->dev, "Failed to acquire HDM lock\n");
1106 mutex_unlock(&c->start_mutex);
1107 return -ENOLCK;
1108 }
1109
1110 c->cfg.extra_len = 0;
1111 if (c->iface->configure(c->iface, c->channel_id, &c->cfg)) {
1112 dev_err(&c->dev, "Channel configuration failed. Go check settings...\n");
1113 ret = -EINVAL;
1114 goto err_put_module;
1115 }
1116
1117 init_waitqueue_head(&c->hdm_fifo_wq);
1118
1119 if (c->cfg.direction == MOST_CH_RX)
1120 num_buffer = arm_mbo_chain(c, c->cfg.direction,
1121 most_read_completion);
1122 else
1123 num_buffer = arm_mbo_chain(c, c->cfg.direction,
1124 most_write_completion);
1125 if (unlikely(!num_buffer)) {
1126 ret = -ENOMEM;
1127 goto err_put_module;
1128 }
1129
1130 ret = run_enqueue_thread(c, id);
1131 if (ret)
1132 goto err_put_module;
1133
1134 c->is_starving = 0;
1135 c->pipe0.num_buffers = c->cfg.num_buffers / 2;
1136 c->pipe1.num_buffers = c->cfg.num_buffers - c->pipe0.num_buffers;
1137 atomic_set(&c->mbo_ref, num_buffer);
1138
1139out:
1140 if (comp == c->pipe0.comp)
1141 c->pipe0.refs++;
1142 if (comp == c->pipe1.comp)
1143 c->pipe1.refs++;
1144 mutex_unlock(&c->start_mutex);
1145 return 0;
1146
1147err_put_module:
1148 module_put(iface->mod);
1149 mutex_unlock(&c->start_mutex);
1150 return ret;
1151}
1152EXPORT_SYMBOL_GPL(most_start_channel);
1153
1154/**
1155 * most_stop_channel - stops a running channel
1156 * @iface: pointer to interface instance
1157 * @id: channel ID
1158 * @comp: driver component
1159 */
1160int most_stop_channel(struct most_interface *iface, int id,
1161 struct most_component *comp)
1162{
1163 struct most_channel *c;
1164
1165 if (unlikely((!iface) || (id >= iface->num_channels) || (id < 0))) {
1166 pr_err("Bad interface or index out of range\n");
1167 return -EINVAL;
1168 }
1169 c = iface->p->channel[id];
1170 if (unlikely(!c))
1171 return -EINVAL;
1172
1173 mutex_lock(&c->start_mutex);
1174 if (c->pipe0.refs + c->pipe1.refs >= 2)
1175 goto out;
1176
1177 if (c->hdm_enqueue_task)
1178 kthread_stop(c->hdm_enqueue_task);
1179 c->hdm_enqueue_task = NULL;
1180
1181 if (iface->mod)
1182 module_put(iface->mod);
1183
1184 c->is_poisoned = true;
1185 if (c->iface->poison_channel(c->iface, c->channel_id)) {
1186 dev_err(&c->dev, "Failed to stop channel %d of interface %s\n", c->channel_id,
1187 c->iface->description);
1188 mutex_unlock(&c->start_mutex);
1189 return -EAGAIN;
1190 }
1191 flush_trash_fifo(c);
1192 flush_channel_fifos(c);
1193
1194#ifdef CMPL_INTERRUPTIBLE
1195 if (wait_for_completion_interruptible(&c->cleanup)) {
1196 dev_err(&c->dev, "Interrupted while cleaning up channel %d\n", c->channel_id);
1197 mutex_unlock(&c->start_mutex);
1198 return -EINTR;
1199 }
1200#else
1201 wait_for_completion(&c->cleanup);
1202#endif
1203 c->is_poisoned = false;
1204
1205out:
1206 if (comp == c->pipe0.comp)
1207 c->pipe0.refs--;
1208 if (comp == c->pipe1.comp)
1209 c->pipe1.refs--;
1210 mutex_unlock(&c->start_mutex);
1211 return 0;
1212}
1213EXPORT_SYMBOL_GPL(most_stop_channel);
1214
1215/**
1216 * most_register_component - registers a driver component with the core
1217 * @comp: driver component
1218 */
1219int most_register_component(struct most_component *comp)
1220{
1221 if (!comp) {
1222 pr_err("Bad component\n");
1223 return -EINVAL;
1224 }
1225 list_add_tail(&comp->list, &comp_list);
1226 return 0;
1227}
1228EXPORT_SYMBOL_GPL(most_register_component);
1229
1230static int disconnect_channels(struct device *dev, void *data)
1231{
1232 struct most_interface *iface;
1233 struct most_channel *c, *tmp;
1234 struct most_component *comp = data;
1235
1236 iface = dev_get_drvdata(dev);
1237 list_for_each_entry_safe(c, tmp, &iface->p->channel_list, list) {
1238 if (c->pipe0.comp == comp || c->pipe1.comp == comp)
1239 comp->disconnect_channel(c->iface, c->channel_id);
1240 if (c->pipe0.comp == comp)
1241 c->pipe0.comp = NULL;
1242 if (c->pipe1.comp == comp)
1243 c->pipe1.comp = NULL;
1244 }
1245 return 0;
1246}
1247
1248/**
1249 * most_deregister_component - deregisters a driver component with the core
1250 * @comp: driver component
1251 */
1252int most_deregister_component(struct most_component *comp)
1253{
1254 if (!comp) {
1255 pr_err("Bad component\n");
1256 return -EINVAL;
1257 }
1258
1259 bus_for_each_dev(&mostbus, NULL, comp, disconnect_channels);
1260 list_del(&comp->list);
1261 return 0;
1262}
1263EXPORT_SYMBOL_GPL(most_deregister_component);
1264
1265static void release_channel(struct device *dev)
1266{
1267 struct most_channel *c = to_channel(dev);
1268
1269 kfree(c);
1270}
1271
1272/**
1273 * most_register_interface - registers an interface with core
1274 * @iface: device interface
1275 *
1276 * Allocates and initializes a new interface instance and all of its channels.
1277 * Returns a pointer to kobject or an error pointer.
1278 */
1279int most_register_interface(struct most_interface *iface)
1280{
1281 unsigned int i;
1282 int id;
1283 struct most_channel *c;
1284
1285 if (!iface)
1286 return -EINVAL;
1287
1288 device_initialize(iface->dev);
1289
1290 if (!iface->enqueue || !iface->configure || !iface->poison_channel ||
1291 (iface->num_channels > MAX_CHANNELS)) {
1292 put_device(iface->dev);
1293 return -EINVAL;
1294 }
1295
1296 id = ida_alloc(&mdev_id, GFP_KERNEL);
1297 if (id < 0) {
1298 dev_err(iface->dev, "Failed to allocate device ID\n");
1299 put_device(iface->dev);
1300 return id;
1301 }
1302
1303 iface->p = kzalloc_obj(*iface->p);
1304 if (!iface->p) {
1305 ida_free(&mdev_id, id);
1306 put_device(iface->dev);
1307 return -ENOMEM;
1308 }
1309
1310 INIT_LIST_HEAD(&iface->p->channel_list);
1311 iface->p->dev_id = id;
1312 strscpy(iface->p->name, iface->description, sizeof(iface->p->name));
1313 iface->dev->bus = &mostbus;
1314 iface->dev->groups = interface_attr_groups;
1315 dev_set_drvdata(iface->dev, iface);
1316 if (device_add(iface->dev)) {
1317 dev_err(iface->dev, "Failed to register interface device\n");
1318 kfree(iface->p);
1319 put_device(iface->dev);
1320 ida_free(&mdev_id, id);
1321 return -ENOMEM;
1322 }
1323
1324 for (i = 0; i < iface->num_channels; i++) {
1325 const char *name_suffix = iface->channel_vector[i].name_suffix;
1326
1327 c = kzalloc_obj(*c);
1328 if (!c)
1329 goto err_free_resources;
1330 if (!name_suffix)
1331 snprintf(c->name, STRING_SIZE, "ch%d", i);
1332 else
1333 snprintf(c->name, STRING_SIZE, "%s", name_suffix);
1334 c->dev.init_name = c->name;
1335 c->dev.parent = iface->dev;
1336 c->dev.groups = channel_attr_groups;
1337 c->dev.release = release_channel;
1338 iface->p->channel[i] = c;
1339 c->is_starving = 0;
1340 c->iface = iface;
1341 c->channel_id = i;
1342 c->keep_mbo = false;
1343 c->enqueue_halt = false;
1344 c->is_poisoned = false;
1345 c->cfg.direction = 0;
1346 c->cfg.data_type = 0;
1347 c->cfg.num_buffers = 0;
1348 c->cfg.buffer_size = 0;
1349 c->cfg.subbuffer_size = 0;
1350 c->cfg.packets_per_xact = 0;
1351 spin_lock_init(&c->fifo_lock);
1352 INIT_LIST_HEAD(&c->fifo);
1353 INIT_LIST_HEAD(&c->trash_fifo);
1354 INIT_LIST_HEAD(&c->halt_fifo);
1355 init_completion(&c->cleanup);
1356 atomic_set(&c->mbo_ref, 0);
1357 mutex_init(&c->start_mutex);
1358 mutex_init(&c->nq_mutex);
1359 list_add_tail(&c->list, &iface->p->channel_list);
1360 if (device_register(&c->dev)) {
1361 dev_err(&c->dev, "Failed to register channel device\n");
1362 goto err_free_most_channel;
1363 }
1364 }
1365 most_interface_register_notify(iface->description);
1366 return 0;
1367
1368err_free_most_channel:
1369 put_device(&c->dev);
1370
1371err_free_resources:
1372 while (i > 0) {
1373 c = iface->p->channel[--i];
1374 device_unregister(&c->dev);
1375 }
1376 kfree(iface->p);
1377 device_unregister(iface->dev);
1378 ida_free(&mdev_id, id);
1379 return -ENOMEM;
1380}
1381EXPORT_SYMBOL_GPL(most_register_interface);
1382
1383/**
1384 * most_deregister_interface - deregisters an interface with core
1385 * @iface: device interface
1386 *
1387 * Before removing an interface instance from the list, all running
1388 * channels are stopped and poisoned.
1389 */
1390void most_deregister_interface(struct most_interface *iface)
1391{
1392 int i;
1393 struct most_channel *c;
1394
1395 for (i = 0; i < iface->num_channels; i++) {
1396 c = iface->p->channel[i];
1397 if (c->pipe0.comp)
1398 c->pipe0.comp->disconnect_channel(c->iface,
1399 c->channel_id);
1400 if (c->pipe1.comp)
1401 c->pipe1.comp->disconnect_channel(c->iface,
1402 c->channel_id);
1403 c->pipe0.comp = NULL;
1404 c->pipe1.comp = NULL;
1405 list_del(&c->list);
1406 device_unregister(&c->dev);
1407 }
1408
1409 ida_free(&mdev_id, iface->p->dev_id);
1410 kfree(iface->p);
1411 device_unregister(iface->dev);
1412}
1413EXPORT_SYMBOL_GPL(most_deregister_interface);
1414
1415/**
1416 * most_stop_enqueue - prevents core from enqueueing MBOs
1417 * @iface: pointer to interface
1418 * @id: channel id
1419 *
1420 * This is called by an HDM that _cannot_ attend to its duties and
1421 * is imminent to get run over by the core. The core is not going to
1422 * enqueue any further packets unless the flagging HDM calls
1423 * most_resume enqueue().
1424 */
1425void most_stop_enqueue(struct most_interface *iface, int id)
1426{
1427 struct most_channel *c = iface->p->channel[id];
1428
1429 if (!c)
1430 return;
1431
1432 mutex_lock(&c->nq_mutex);
1433 c->enqueue_halt = true;
1434 mutex_unlock(&c->nq_mutex);
1435}
1436EXPORT_SYMBOL_GPL(most_stop_enqueue);
1437
1438/**
1439 * most_resume_enqueue - allow core to enqueue MBOs again
1440 * @iface: pointer to interface
1441 * @id: channel id
1442 *
1443 * This clears the enqueue halt flag and enqueues all MBOs currently
1444 * sitting in the wait fifo.
1445 */
1446void most_resume_enqueue(struct most_interface *iface, int id)
1447{
1448 struct most_channel *c = iface->p->channel[id];
1449
1450 if (!c)
1451 return;
1452
1453 mutex_lock(&c->nq_mutex);
1454 c->enqueue_halt = false;
1455 mutex_unlock(&c->nq_mutex);
1456
1457 wake_up_interruptible(&c->hdm_fifo_wq);
1458}
1459EXPORT_SYMBOL_GPL(most_resume_enqueue);
1460
1461static int __init most_init(void)
1462{
1463 int err;
1464
1465 INIT_LIST_HEAD(&comp_list);
1466 ida_init(&mdev_id);
1467
1468 err = bus_register(&mostbus);
1469 if (err) {
1470 pr_err("Failed to register most bus\n");
1471 return err;
1472 }
1473 err = driver_register(&mostbus_driver);
1474 if (err) {
1475 pr_err("Failed to register core driver\n");
1476 goto err_unregister_bus;
1477 }
1478 configfs_init();
1479 return 0;
1480
1481err_unregister_bus:
1482 bus_unregister(&mostbus);
1483 return err;
1484}
1485
1486static void __exit most_exit(void)
1487{
1488 driver_unregister(&mostbus_driver);
1489 bus_unregister(&mostbus);
1490 ida_destroy(&mdev_id);
1491}
1492
1493subsys_initcall(most_init);
1494module_exit(most_exit);
1495MODULE_LICENSE("GPL");
1496MODULE_AUTHOR("Christian Gromm <[email protected]>");
1497MODULE_DESCRIPTION("Core module of stacked MOST Linux driver");