xref: /linux/drivers/most/core.c (revision a1ff5a7d78a036d6c2178ee5acd6ba4946243800)
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 
28 static struct ida mdev_id;
29 static int dummy_num_buffers;
30 static struct list_head comp_list;
31 
32 struct pipe {
33 	struct most_component *comp;
34 	int refs;
35 	int num_buffers;
36 };
37 
38 struct 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 
67 struct 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 
74 static 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  */
most_free_mbo_coherent(struct mbo * mbo)100 static 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  */
flush_channel_fifos(struct most_channel * c)118 static 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  */
flush_trash_fifo(struct most_channel * c)152 static 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 
available_directions_show(struct device * dev,struct device_attribute * attr,char * buf)168 static 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 
available_datatypes_show(struct device * dev,struct device_attribute * attr,char * buf)184 static 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 
number_of_packet_buffers_show(struct device * dev,struct device_attribute * attr,char * buf)204 static 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 
number_of_stream_buffers_show(struct device * dev,struct device_attribute * attr,char * buf)215 static 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 
size_of_packet_buffer_show(struct device * dev,struct device_attribute * attr,char * buf)226 static 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 
size_of_stream_buffer_show(struct device * dev,struct device_attribute * attr,char * buf)237 static 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 
channel_starving_show(struct device * dev,struct device_attribute * attr,char * buf)248 static 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 
set_number_of_buffers_show(struct device * dev,struct device_attribute * attr,char * buf)257 static 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 
set_buffer_size_show(struct device * dev,struct device_attribute * attr,char * buf)266 static 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 
set_direction_show(struct device * dev,struct device_attribute * attr,char * buf)275 static 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 
set_datatype_show(struct device * dev,struct device_attribute * attr,char * buf)288 static 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 
set_subbuffer_size_show(struct device * dev,struct device_attribute * attr,char * buf)303 static 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 
set_packets_per_xact_show(struct device * dev,struct device_attribute * attr,char * buf)312 static 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 
set_dbr_size_show(struct device * dev,struct device_attribute * attr,char * buf)321 static 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)
channel_attr_is_visible(struct kobject * kobj,struct attribute * attr,int index)330 static 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 
349 static DEVICE_ATTR_RO(available_directions);
350 static DEVICE_ATTR_RO(available_datatypes);
351 static DEVICE_ATTR_RO(number_of_packet_buffers);
352 static DEVICE_ATTR_RO(number_of_stream_buffers);
353 static DEVICE_ATTR_RO(size_of_stream_buffer);
354 static DEVICE_ATTR_RO(size_of_packet_buffer);
355 static DEVICE_ATTR_RO(channel_starving);
356 static DEVICE_ATTR_RO(set_buffer_size);
357 static DEVICE_ATTR_RO(set_number_of_buffers);
358 static DEVICE_ATTR_RO(set_direction);
359 static DEVICE_ATTR_RO(set_datatype);
360 static DEVICE_ATTR_RO(set_subbuffer_size);
361 static DEVICE_ATTR_RO(set_packets_per_xact);
362 static DEVICE_ATTR_RO(set_dbr_size);
363 
364 static 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 
382 static const struct attribute_group channel_attr_group = {
383 	.attrs = channel_attrs,
384 	.is_visible = channel_attr_is_visible,
385 };
386 
387 static const struct attribute_group *channel_attr_groups[] = {
388 	&channel_attr_group,
389 	NULL,
390 };
391 
description_show(struct device * dev,struct device_attribute * attr,char * buf)392 static 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 
interface_show(struct device * dev,struct device_attribute * attr,char * buf)401 static 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 
430 static DEVICE_ATTR_RO(description);
431 static DEVICE_ATTR_RO(interface);
432 
433 static struct attribute *interface_attrs[] = {
434 	DEV_ATTR(description),
435 	DEV_ATTR(interface),
436 	NULL,
437 };
438 
439 static const struct attribute_group interface_attr_group = {
440 	.attrs = interface_attrs,
441 };
442 
443 static const struct attribute_group *interface_attr_groups[] = {
444 	&interface_attr_group,
445 	NULL,
446 };
447 
match_component(char * name)448 static 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 
459 struct show_links_data {
460 	int offs;
461 	char *buf;
462 };
463 
print_links(struct device * dev,void * data)464 static 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 
most_match(struct device * dev,const struct device_driver * drv)494 static 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 
502 static const struct bus_type mostbus = {
503 	.name = "most",
504 	.match = most_match,
505 };
506 
links_show(struct device_driver * drv,char * buf)507 static 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 
components_show(struct device_driver * drv,char * buf)515 static 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  */
get_channel(char * mdev,char * mdev_ch)532 static 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 	put_device(dev);
542 	iface = dev_get_drvdata(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 
550 static
link_channel_to_component(struct most_channel * c,struct most_component * comp,char * name,char * comp_param)551 inline 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 
most_set_cfg_buffer_size(char * mdev,char * mdev_ch,u16 val)576 int 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 
most_set_cfg_subbuffer_size(char * mdev,char * mdev_ch,u16 val)586 int 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 
most_set_cfg_dbr_size(char * mdev,char * mdev_ch,u16 val)596 int 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 
most_set_cfg_num_buffers(char * mdev,char * mdev_ch,u16 val)606 int 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 
most_set_cfg_datatype(char * mdev,char * mdev_ch,char * buf)616 int 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 
most_set_cfg_direction(char * mdev,char * mdev_ch,char * buf)635 int 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 
most_set_cfg_packets_xact(char * mdev,char * mdev_ch,u16 val)656 int 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 
most_cfg_complete(char * comp_name)666 int 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 
most_add_link(char * mdev,char * mdev_ch,char * comp_name,char * link_name,char * comp_param)677 int 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 
most_remove_link(char * mdev,char * mdev_ch,char * comp_name)689 int 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 
712 static DRIVER_ATTR_RO(links);
713 static DRIVER_ATTR_RO(components);
714 
715 static struct attribute *mc_attrs[] = {
716 	DRV_ATTR(links),
717 	DRV_ATTR(components),
718 	NULL,
719 };
720 
721 static const struct attribute_group mc_attr_group = {
722 	.attrs = mc_attrs,
723 };
724 
725 static const struct attribute_group *mc_attr_groups[] = {
726 	&mc_attr_group,
727 	NULL,
728 };
729 
730 static struct device_driver mostbus_driver = {
731 	.name = "most_core",
732 	.bus = &mostbus,
733 	.groups = mc_attr_groups,
734 };
735 
trash_mbo(struct mbo * mbo)736 static 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 
hdm_mbo_ready(struct most_channel * c)746 static 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 
nq_hdm_mbo(struct mbo * mbo)760 static 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 
hdm_enqueue_thread(void * data)771 static 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 
run_enqueue_thread(struct most_channel * c,int channel_id)811 static 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  */
arm_mbo(struct mbo * mbo)835 static 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  */
arm_mbo_chain(struct most_channel * c,int dir,void (* compl)(struct mbo *))872 static 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(sizeof(*mbo), GFP_KERNEL);
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 
913 release_mbo:
914 	kfree(mbo);
915 
916 flush_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  */
most_submit_mbo(struct mbo * mbo)925 void 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 }
933 EXPORT_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  */
most_write_completion(struct mbo * mbo)942 static 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 
channel_has_mbo(struct most_interface * iface,int id,struct most_component * comp)953 int 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 }
973 EXPORT_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  */
most_get_mbo(struct most_interface * iface,int id,struct most_component * comp)984 struct 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 }
1021 EXPORT_SYMBOL_GPL(most_get_mbo);
1022 
1023 /**
1024  * most_put_mbo - return buffer to pool
1025  * @mbo: most buffer
1026  */
most_put_mbo(struct mbo * mbo)1027 void 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 }
1038 EXPORT_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  */
most_read_completion(struct mbo * mbo)1050 static 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  */
most_start_channel(struct most_interface * iface,int id,struct most_component * comp)1090 int 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 
1139 out:
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 
1147 err_put_module:
1148 	module_put(iface->mod);
1149 	mutex_unlock(&c->start_mutex);
1150 	return ret;
1151 }
1152 EXPORT_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  */
most_stop_channel(struct most_interface * iface,int id,struct most_component * comp)1160 int 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 
1205 out:
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 }
1213 EXPORT_SYMBOL_GPL(most_stop_channel);
1214 
1215 /**
1216  * most_register_component - registers a driver component with the core
1217  * @comp: driver component
1218  */
most_register_component(struct most_component * comp)1219 int 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 }
1228 EXPORT_SYMBOL_GPL(most_register_component);
1229 
disconnect_channels(struct device * dev,void * data)1230 static 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  */
most_deregister_component(struct most_component * comp)1252 int 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 }
1263 EXPORT_SYMBOL_GPL(most_deregister_component);
1264 
release_channel(struct device * dev)1265 static 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  */
most_register_interface(struct most_interface * iface)1279 int most_register_interface(struct most_interface *iface)
1280 {
1281 	unsigned int i;
1282 	int id;
1283 	struct most_channel *c;
1284 
1285 	if (!iface || !iface->enqueue || !iface->configure ||
1286 	    !iface->poison_channel || (iface->num_channels > MAX_CHANNELS))
1287 		return -EINVAL;
1288 
1289 	id = ida_alloc(&mdev_id, GFP_KERNEL);
1290 	if (id < 0) {
1291 		dev_err(iface->dev, "Failed to allocate device ID\n");
1292 		return id;
1293 	}
1294 
1295 	iface->p = kzalloc(sizeof(*iface->p), GFP_KERNEL);
1296 	if (!iface->p) {
1297 		ida_free(&mdev_id, id);
1298 		return -ENOMEM;
1299 	}
1300 
1301 	INIT_LIST_HEAD(&iface->p->channel_list);
1302 	iface->p->dev_id = id;
1303 	strscpy(iface->p->name, iface->description, sizeof(iface->p->name));
1304 	iface->dev->bus = &mostbus;
1305 	iface->dev->groups = interface_attr_groups;
1306 	dev_set_drvdata(iface->dev, iface);
1307 	if (device_register(iface->dev)) {
1308 		dev_err(iface->dev, "Failed to register interface device\n");
1309 		kfree(iface->p);
1310 		put_device(iface->dev);
1311 		ida_free(&mdev_id, id);
1312 		return -ENOMEM;
1313 	}
1314 
1315 	for (i = 0; i < iface->num_channels; i++) {
1316 		const char *name_suffix = iface->channel_vector[i].name_suffix;
1317 
1318 		c = kzalloc(sizeof(*c), GFP_KERNEL);
1319 		if (!c)
1320 			goto err_free_resources;
1321 		if (!name_suffix)
1322 			snprintf(c->name, STRING_SIZE, "ch%d", i);
1323 		else
1324 			snprintf(c->name, STRING_SIZE, "%s", name_suffix);
1325 		c->dev.init_name = c->name;
1326 		c->dev.parent = iface->dev;
1327 		c->dev.groups = channel_attr_groups;
1328 		c->dev.release = release_channel;
1329 		iface->p->channel[i] = c;
1330 		c->is_starving = 0;
1331 		c->iface = iface;
1332 		c->channel_id = i;
1333 		c->keep_mbo = false;
1334 		c->enqueue_halt = false;
1335 		c->is_poisoned = false;
1336 		c->cfg.direction = 0;
1337 		c->cfg.data_type = 0;
1338 		c->cfg.num_buffers = 0;
1339 		c->cfg.buffer_size = 0;
1340 		c->cfg.subbuffer_size = 0;
1341 		c->cfg.packets_per_xact = 0;
1342 		spin_lock_init(&c->fifo_lock);
1343 		INIT_LIST_HEAD(&c->fifo);
1344 		INIT_LIST_HEAD(&c->trash_fifo);
1345 		INIT_LIST_HEAD(&c->halt_fifo);
1346 		init_completion(&c->cleanup);
1347 		atomic_set(&c->mbo_ref, 0);
1348 		mutex_init(&c->start_mutex);
1349 		mutex_init(&c->nq_mutex);
1350 		list_add_tail(&c->list, &iface->p->channel_list);
1351 		if (device_register(&c->dev)) {
1352 			dev_err(&c->dev, "Failed to register channel device\n");
1353 			goto err_free_most_channel;
1354 		}
1355 	}
1356 	most_interface_register_notify(iface->description);
1357 	return 0;
1358 
1359 err_free_most_channel:
1360 	put_device(&c->dev);
1361 
1362 err_free_resources:
1363 	while (i > 0) {
1364 		c = iface->p->channel[--i];
1365 		device_unregister(&c->dev);
1366 	}
1367 	kfree(iface->p);
1368 	device_unregister(iface->dev);
1369 	ida_free(&mdev_id, id);
1370 	return -ENOMEM;
1371 }
1372 EXPORT_SYMBOL_GPL(most_register_interface);
1373 
1374 /**
1375  * most_deregister_interface - deregisters an interface with core
1376  * @iface: device interface
1377  *
1378  * Before removing an interface instance from the list, all running
1379  * channels are stopped and poisoned.
1380  */
most_deregister_interface(struct most_interface * iface)1381 void most_deregister_interface(struct most_interface *iface)
1382 {
1383 	int i;
1384 	struct most_channel *c;
1385 
1386 	for (i = 0; i < iface->num_channels; i++) {
1387 		c = iface->p->channel[i];
1388 		if (c->pipe0.comp)
1389 			c->pipe0.comp->disconnect_channel(c->iface,
1390 							c->channel_id);
1391 		if (c->pipe1.comp)
1392 			c->pipe1.comp->disconnect_channel(c->iface,
1393 							c->channel_id);
1394 		c->pipe0.comp = NULL;
1395 		c->pipe1.comp = NULL;
1396 		list_del(&c->list);
1397 		device_unregister(&c->dev);
1398 	}
1399 
1400 	ida_free(&mdev_id, iface->p->dev_id);
1401 	kfree(iface->p);
1402 	device_unregister(iface->dev);
1403 }
1404 EXPORT_SYMBOL_GPL(most_deregister_interface);
1405 
1406 /**
1407  * most_stop_enqueue - prevents core from enqueueing MBOs
1408  * @iface: pointer to interface
1409  * @id: channel id
1410  *
1411  * This is called by an HDM that _cannot_ attend to its duties and
1412  * is imminent to get run over by the core. The core is not going to
1413  * enqueue any further packets unless the flagging HDM calls
1414  * most_resume enqueue().
1415  */
most_stop_enqueue(struct most_interface * iface,int id)1416 void most_stop_enqueue(struct most_interface *iface, int id)
1417 {
1418 	struct most_channel *c = iface->p->channel[id];
1419 
1420 	if (!c)
1421 		return;
1422 
1423 	mutex_lock(&c->nq_mutex);
1424 	c->enqueue_halt = true;
1425 	mutex_unlock(&c->nq_mutex);
1426 }
1427 EXPORT_SYMBOL_GPL(most_stop_enqueue);
1428 
1429 /**
1430  * most_resume_enqueue - allow core to enqueue MBOs again
1431  * @iface: pointer to interface
1432  * @id: channel id
1433  *
1434  * This clears the enqueue halt flag and enqueues all MBOs currently
1435  * sitting in the wait fifo.
1436  */
most_resume_enqueue(struct most_interface * iface,int id)1437 void most_resume_enqueue(struct most_interface *iface, int id)
1438 {
1439 	struct most_channel *c = iface->p->channel[id];
1440 
1441 	if (!c)
1442 		return;
1443 
1444 	mutex_lock(&c->nq_mutex);
1445 	c->enqueue_halt = false;
1446 	mutex_unlock(&c->nq_mutex);
1447 
1448 	wake_up_interruptible(&c->hdm_fifo_wq);
1449 }
1450 EXPORT_SYMBOL_GPL(most_resume_enqueue);
1451 
most_init(void)1452 static int __init most_init(void)
1453 {
1454 	int err;
1455 
1456 	INIT_LIST_HEAD(&comp_list);
1457 	ida_init(&mdev_id);
1458 
1459 	err = bus_register(&mostbus);
1460 	if (err) {
1461 		pr_err("Failed to register most bus\n");
1462 		return err;
1463 	}
1464 	err = driver_register(&mostbus_driver);
1465 	if (err) {
1466 		pr_err("Failed to register core driver\n");
1467 		goto err_unregister_bus;
1468 	}
1469 	configfs_init();
1470 	return 0;
1471 
1472 err_unregister_bus:
1473 	bus_unregister(&mostbus);
1474 	return err;
1475 }
1476 
most_exit(void)1477 static void __exit most_exit(void)
1478 {
1479 	driver_unregister(&mostbus_driver);
1480 	bus_unregister(&mostbus);
1481 	ida_destroy(&mdev_id);
1482 }
1483 
1484 subsys_initcall(most_init);
1485 module_exit(most_exit);
1486 MODULE_LICENSE("GPL");
1487 MODULE_AUTHOR("Christian Gromm <christian.gromm@microchip.com>");
1488 MODULE_DESCRIPTION("Core module of stacked MOST Linux driver");
1489