1 /*
2 * Loopback bridge driver for the Greybus loopback module.
3 *
4 * Copyright 2014 Google Inc.
5 * Copyright 2014 Linaro Ltd.
6 *
7 * Released under the GPLv2 only.
8 */
9
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/mutex.h>
15 #include <linux/slab.h>
16 #include <linux/kthread.h>
17 #include <linux/delay.h>
18 #include <linux/random.h>
19 #include <linux/sizes.h>
20 #include <linux/cdev.h>
21 #include <linux/fs.h>
22 #include <linux/kfifo.h>
23 #include <linux/debugfs.h>
24 #include <linux/list_sort.h>
25 #include <linux/spinlock.h>
26 #include <linux/workqueue.h>
27 #include <linux/atomic.h>
28 #include <linux/pm_runtime.h>
29
30 #include <asm/div64.h>
31
32 #include "greybus.h"
33 #include "connection.h"
34
35 #define NSEC_PER_DAY 86400000000000ULL
36
37 struct gb_loopback_stats {
38 u32 min;
39 u32 max;
40 u64 sum;
41 u32 count;
42 };
43
44 struct gb_loopback_device {
45 struct dentry *root;
46 u32 count;
47 size_t size_max;
48
49 /* We need to take a lock in atomic context */
50 spinlock_t lock;
51 struct list_head list;
52 struct list_head list_op_async;
53 wait_queue_head_t wq;
54 };
55
56 static struct gb_loopback_device gb_dev;
57
58 struct gb_loopback_async_operation {
59 struct gb_loopback *gb;
60 struct gb_operation *operation;
61 struct timeval ts;
62 struct timer_list timer;
63 struct list_head entry;
64 struct work_struct work;
65 struct kref kref;
66 bool pending;
67 int (*completion)(struct gb_loopback_async_operation *op_async);
68 };
69
70 struct gb_loopback {
71 struct gb_connection *connection;
72
73 struct dentry *file;
74 struct kfifo kfifo_lat;
75 struct kfifo kfifo_ts;
76 struct mutex mutex;
77 struct task_struct *task;
78 struct list_head entry;
79 struct device *dev;
80 wait_queue_head_t wq;
81 wait_queue_head_t wq_completion;
82 atomic_t outstanding_operations;
83
84 /* Per connection stats */
85 struct timeval ts;
86 struct gb_loopback_stats latency;
87 struct gb_loopback_stats throughput;
88 struct gb_loopback_stats requests_per_second;
89 struct gb_loopback_stats apbridge_unipro_latency;
90 struct gb_loopback_stats gbphy_firmware_latency;
91
92 int type;
93 int async;
94 int id;
95 u32 size;
96 u32 iteration_max;
97 u32 iteration_count;
98 int us_wait;
99 u32 error;
100 u32 requests_completed;
101 u32 requests_timedout;
102 u32 timeout;
103 u32 jiffy_timeout;
104 u32 timeout_min;
105 u32 timeout_max;
106 u32 outstanding_operations_max;
107 u32 lbid;
108 u64 elapsed_nsecs;
109 u32 apbridge_latency_ts;
110 u32 gbphy_latency_ts;
111
112 u32 send_count;
113 };
114
115 static struct class loopback_class = {
116 .name = "gb_loopback",
117 .owner = THIS_MODULE,
118 };
119 static DEFINE_IDA(loopback_ida);
120
121 /* Min/max values in jiffies */
122 #define GB_LOOPBACK_TIMEOUT_MIN 1
123 #define GB_LOOPBACK_TIMEOUT_MAX 10000
124
125 #define GB_LOOPBACK_FIFO_DEFAULT 8192
126
127 static unsigned kfifo_depth = GB_LOOPBACK_FIFO_DEFAULT;
128 module_param(kfifo_depth, uint, 0444);
129
130 /* Maximum size of any one send data buffer we support */
131 #define MAX_PACKET_SIZE (PAGE_SIZE * 2)
132
133 #define GB_LOOPBACK_US_WAIT_MAX 1000000
134
135 /* interface sysfs attributes */
136 #define gb_loopback_ro_attr(field) \
137 static ssize_t field##_show(struct device *dev, \
138 struct device_attribute *attr, \
139 char *buf) \
140 { \
141 struct gb_loopback *gb = dev_get_drvdata(dev); \
142 return sprintf(buf, "%u\n", gb->field); \
143 } \
144 static DEVICE_ATTR_RO(field)
145
146 #define gb_loopback_ro_stats_attr(name, field, type) \
147 static ssize_t name##_##field##_show(struct device *dev, \
148 struct device_attribute *attr, \
149 char *buf) \
150 { \
151 struct gb_loopback *gb = dev_get_drvdata(dev); \
152 /* Report 0 for min and max if no transfer successed */ \
153 if (!gb->requests_completed) \
154 return sprintf(buf, "0\n"); \
155 return sprintf(buf, "%"#type"\n", gb->name.field); \
156 } \
157 static DEVICE_ATTR_RO(name##_##field)
158
159 #define gb_loopback_ro_avg_attr(name) \
160 static ssize_t name##_avg_show(struct device *dev, \
161 struct device_attribute *attr, \
162 char *buf) \
163 { \
164 struct gb_loopback_stats *stats; \
165 struct gb_loopback *gb; \
166 u64 avg, rem; \
167 u32 count; \
168 gb = dev_get_drvdata(dev); \
169 stats = &gb->name; \
170 count = stats->count ? stats->count : 1; \
171 avg = stats->sum + count / 2000000; /* round closest */ \
172 rem = do_div(avg, count); \
173 rem *= 1000000; \
174 do_div(rem, count); \
175 return sprintf(buf, "%llu.%06u\n", avg, (u32)rem); \
176 } \
177 static DEVICE_ATTR_RO(name##_avg)
178
179 #define gb_loopback_stats_attrs(field) \
180 gb_loopback_ro_stats_attr(field, min, u); \
181 gb_loopback_ro_stats_attr(field, max, u); \
182 gb_loopback_ro_avg_attr(field)
183
184 #define gb_loopback_attr(field, type) \
185 static ssize_t field##_show(struct device *dev, \
186 struct device_attribute *attr, \
187 char *buf) \
188 { \
189 struct gb_loopback *gb = dev_get_drvdata(dev); \
190 return sprintf(buf, "%"#type"\n", gb->field); \
191 } \
192 static ssize_t field##_store(struct device *dev, \
193 struct device_attribute *attr, \
194 const char *buf, \
195 size_t len) \
196 { \
197 int ret; \
198 struct gb_loopback *gb = dev_get_drvdata(dev); \
199 mutex_lock(&gb->mutex); \
200 ret = sscanf(buf, "%"#type, &gb->field); \
201 if (ret != 1) \
202 len = -EINVAL; \
203 else \
204 gb_loopback_check_attr(gb, bundle); \
205 mutex_unlock(&gb->mutex); \
206 return len; \
207 } \
208 static DEVICE_ATTR_RW(field)
209
210 #define gb_dev_loopback_ro_attr(field, conn) \
211 static ssize_t field##_show(struct device *dev, \
212 struct device_attribute *attr, \
213 char *buf) \
214 { \
215 struct gb_loopback *gb = dev_get_drvdata(dev); \
216 return sprintf(buf, "%u\n", gb->field); \
217 } \
218 static DEVICE_ATTR_RO(field)
219
220 #define gb_dev_loopback_rw_attr(field, type) \
221 static ssize_t field##_show(struct device *dev, \
222 struct device_attribute *attr, \
223 char *buf) \
224 { \
225 struct gb_loopback *gb = dev_get_drvdata(dev); \
226 return sprintf(buf, "%"#type"\n", gb->field); \
227 } \
228 static ssize_t field##_store(struct device *dev, \
229 struct device_attribute *attr, \
230 const char *buf, \
231 size_t len) \
232 { \
233 int ret; \
234 struct gb_loopback *gb = dev_get_drvdata(dev); \
235 mutex_lock(&gb->mutex); \
236 ret = sscanf(buf, "%"#type, &gb->field); \
237 if (ret != 1) \
238 len = -EINVAL; \
239 else \
240 gb_loopback_check_attr(gb); \
241 mutex_unlock(&gb->mutex); \
242 return len; \
243 } \
244 static DEVICE_ATTR_RW(field)
245
246 static void gb_loopback_reset_stats(struct gb_loopback *gb);
gb_loopback_check_attr(struct gb_loopback * gb)247 static void gb_loopback_check_attr(struct gb_loopback *gb)
248 {
249 if (gb->us_wait > GB_LOOPBACK_US_WAIT_MAX)
250 gb->us_wait = GB_LOOPBACK_US_WAIT_MAX;
251 if (gb->size > gb_dev.size_max)
252 gb->size = gb_dev.size_max;
253 gb->requests_timedout = 0;
254 gb->requests_completed = 0;
255 gb->iteration_count = 0;
256 gb->send_count = 0;
257 gb->error = 0;
258
259 if (kfifo_depth < gb->iteration_max) {
260 dev_warn(gb->dev,
261 "cannot log bytes %u kfifo_depth %u\n",
262 gb->iteration_max, kfifo_depth);
263 }
264 kfifo_reset_out(&gb->kfifo_lat);
265 kfifo_reset_out(&gb->kfifo_ts);
266
267 switch (gb->type) {
268 case GB_LOOPBACK_TYPE_PING:
269 case GB_LOOPBACK_TYPE_TRANSFER:
270 case GB_LOOPBACK_TYPE_SINK:
271 gb->jiffy_timeout = usecs_to_jiffies(gb->timeout);
272 if (!gb->jiffy_timeout)
273 gb->jiffy_timeout = GB_LOOPBACK_TIMEOUT_MIN;
274 else if (gb->jiffy_timeout > GB_LOOPBACK_TIMEOUT_MAX)
275 gb->jiffy_timeout = GB_LOOPBACK_TIMEOUT_MAX;
276 gb_loopback_reset_stats(gb);
277 wake_up(&gb->wq);
278 break;
279 default:
280 gb->type = 0;
281 break;
282 }
283 }
284
285 /* Time to send and receive one message */
286 gb_loopback_stats_attrs(latency);
287 /* Number of requests sent per second on this cport */
288 gb_loopback_stats_attrs(requests_per_second);
289 /* Quantity of data sent and received on this cport */
290 gb_loopback_stats_attrs(throughput);
291 /* Latency across the UniPro link from APBridge's perspective */
292 gb_loopback_stats_attrs(apbridge_unipro_latency);
293 /* Firmware induced overhead in the GPBridge */
294 gb_loopback_stats_attrs(gbphy_firmware_latency);
295
296 /* Number of errors encountered during loop */
297 gb_loopback_ro_attr(error);
298 /* Number of requests successfully completed async */
299 gb_loopback_ro_attr(requests_completed);
300 /* Number of requests timed out async */
301 gb_loopback_ro_attr(requests_timedout);
302 /* Timeout minimum in useconds */
303 gb_loopback_ro_attr(timeout_min);
304 /* Timeout minimum in useconds */
305 gb_loopback_ro_attr(timeout_max);
306
307 /*
308 * Type of loopback message to send based on protocol type definitions
309 * 0 => Don't send message
310 * 2 => Send ping message continuously (message without payload)
311 * 3 => Send transfer message continuously (message with payload,
312 * payload returned in response)
313 * 4 => Send a sink message (message with payload, no payload in response)
314 */
315 gb_dev_loopback_rw_attr(type, d);
316 /* Size of transfer message payload: 0-4096 bytes */
317 gb_dev_loopback_rw_attr(size, u);
318 /* Time to wait between two messages: 0-1000 ms */
319 gb_dev_loopback_rw_attr(us_wait, d);
320 /* Maximum iterations for a given operation: 1-(2^32-1), 0 implies infinite */
321 gb_dev_loopback_rw_attr(iteration_max, u);
322 /* The current index of the for (i = 0; i < iteration_max; i++) loop */
323 gb_dev_loopback_ro_attr(iteration_count, false);
324 /* A flag to indicate synchronous or asynchronous operations */
325 gb_dev_loopback_rw_attr(async, u);
326 /* Timeout of an individual asynchronous request */
327 gb_dev_loopback_rw_attr(timeout, u);
328 /* Maximum number of in-flight operations before back-off */
329 gb_dev_loopback_rw_attr(outstanding_operations_max, u);
330
331 static struct attribute *loopback_attrs[] = {
332 &dev_attr_latency_min.attr,
333 &dev_attr_latency_max.attr,
334 &dev_attr_latency_avg.attr,
335 &dev_attr_requests_per_second_min.attr,
336 &dev_attr_requests_per_second_max.attr,
337 &dev_attr_requests_per_second_avg.attr,
338 &dev_attr_throughput_min.attr,
339 &dev_attr_throughput_max.attr,
340 &dev_attr_throughput_avg.attr,
341 &dev_attr_apbridge_unipro_latency_min.attr,
342 &dev_attr_apbridge_unipro_latency_max.attr,
343 &dev_attr_apbridge_unipro_latency_avg.attr,
344 &dev_attr_gbphy_firmware_latency_min.attr,
345 &dev_attr_gbphy_firmware_latency_max.attr,
346 &dev_attr_gbphy_firmware_latency_avg.attr,
347 &dev_attr_type.attr,
348 &dev_attr_size.attr,
349 &dev_attr_us_wait.attr,
350 &dev_attr_iteration_count.attr,
351 &dev_attr_iteration_max.attr,
352 &dev_attr_async.attr,
353 &dev_attr_error.attr,
354 &dev_attr_requests_completed.attr,
355 &dev_attr_requests_timedout.attr,
356 &dev_attr_timeout.attr,
357 &dev_attr_outstanding_operations_max.attr,
358 &dev_attr_timeout_min.attr,
359 &dev_attr_timeout_max.attr,
360 NULL,
361 };
362 ATTRIBUTE_GROUPS(loopback);
363
364 static void gb_loopback_calculate_stats(struct gb_loopback *gb, bool error);
365
gb_loopback_nsec_to_usec_latency(u64 elapsed_nsecs)366 static u32 gb_loopback_nsec_to_usec_latency(u64 elapsed_nsecs)
367 {
368 u32 lat;
369
370 do_div(elapsed_nsecs, NSEC_PER_USEC);
371 lat = elapsed_nsecs;
372 return lat;
373 }
374
__gb_loopback_calc_latency(u64 t1,u64 t2)375 static u64 __gb_loopback_calc_latency(u64 t1, u64 t2)
376 {
377 if (t2 > t1)
378 return t2 - t1;
379 else
380 return NSEC_PER_DAY - t2 + t1;
381 }
382
gb_loopback_calc_latency(struct timeval * ts,struct timeval * te)383 static u64 gb_loopback_calc_latency(struct timeval *ts, struct timeval *te)
384 {
385 u64 t1, t2;
386
387 t1 = timeval_to_ns(ts);
388 t2 = timeval_to_ns(te);
389
390 return __gb_loopback_calc_latency(t1, t2);
391 }
392
gb_loopback_push_latency_ts(struct gb_loopback * gb,struct timeval * ts,struct timeval * te)393 static void gb_loopback_push_latency_ts(struct gb_loopback *gb,
394 struct timeval *ts, struct timeval *te)
395 {
396 kfifo_in(&gb->kfifo_ts, (unsigned char *)ts, sizeof(*ts));
397 kfifo_in(&gb->kfifo_ts, (unsigned char *)te, sizeof(*te));
398 }
399
gb_loopback_operation_sync(struct gb_loopback * gb,int type,void * request,int request_size,void * response,int response_size)400 static int gb_loopback_operation_sync(struct gb_loopback *gb, int type,
401 void *request, int request_size,
402 void *response, int response_size)
403 {
404 struct gb_operation *operation;
405 struct timeval ts, te;
406 int ret;
407
408 do_gettimeofday(&ts);
409 operation = gb_operation_create(gb->connection, type, request_size,
410 response_size, GFP_KERNEL);
411 if (!operation)
412 return -ENOMEM;
413
414 if (request_size)
415 memcpy(operation->request->payload, request, request_size);
416
417 ret = gb_operation_request_send_sync(operation);
418 if (ret) {
419 dev_err(&gb->connection->bundle->dev,
420 "synchronous operation failed: %d\n", ret);
421 goto out_put_operation;
422 } else {
423 if (response_size == operation->response->payload_size) {
424 memcpy(response, operation->response->payload,
425 response_size);
426 } else {
427 dev_err(&gb->connection->bundle->dev,
428 "response size %zu expected %d\n",
429 operation->response->payload_size,
430 response_size);
431 ret = -EINVAL;
432 goto out_put_operation;
433 }
434 }
435
436 do_gettimeofday(&te);
437
438 /* Calculate the total time the message took */
439 gb_loopback_push_latency_ts(gb, &ts, &te);
440 gb->elapsed_nsecs = gb_loopback_calc_latency(&ts, &te);
441
442 out_put_operation:
443 gb_operation_put(operation);
444
445 return ret;
446 }
447
__gb_loopback_async_operation_destroy(struct kref * kref)448 static void __gb_loopback_async_operation_destroy(struct kref *kref)
449 {
450 struct gb_loopback_async_operation *op_async;
451
452 op_async = container_of(kref, struct gb_loopback_async_operation, kref);
453
454 list_del(&op_async->entry);
455 if (op_async->operation)
456 gb_operation_put(op_async->operation);
457 atomic_dec(&op_async->gb->outstanding_operations);
458 wake_up(&op_async->gb->wq_completion);
459 kfree(op_async);
460 }
461
gb_loopback_async_operation_get(struct gb_loopback_async_operation * op_async)462 static void gb_loopback_async_operation_get(struct gb_loopback_async_operation
463 *op_async)
464 {
465 kref_get(&op_async->kref);
466 }
467
gb_loopback_async_operation_put(struct gb_loopback_async_operation * op_async)468 static void gb_loopback_async_operation_put(struct gb_loopback_async_operation
469 *op_async)
470 {
471 unsigned long flags;
472
473 spin_lock_irqsave(&gb_dev.lock, flags);
474 kref_put(&op_async->kref, __gb_loopback_async_operation_destroy);
475 spin_unlock_irqrestore(&gb_dev.lock, flags);
476 }
477
478 static struct gb_loopback_async_operation *
gb_loopback_operation_find(u16 id)479 gb_loopback_operation_find(u16 id)
480 {
481 struct gb_loopback_async_operation *op_async;
482 bool found = false;
483 unsigned long flags;
484
485 spin_lock_irqsave(&gb_dev.lock, flags);
486 list_for_each_entry(op_async, &gb_dev.list_op_async, entry) {
487 if (op_async->operation->id == id) {
488 gb_loopback_async_operation_get(op_async);
489 found = true;
490 break;
491 }
492 }
493 spin_unlock_irqrestore(&gb_dev.lock, flags);
494
495 return found ? op_async : NULL;
496 }
497
gb_loopback_async_wait_all(struct gb_loopback * gb)498 static void gb_loopback_async_wait_all(struct gb_loopback *gb)
499 {
500 wait_event(gb->wq_completion,
501 !atomic_read(&gb->outstanding_operations));
502 }
503
gb_loopback_async_operation_callback(struct gb_operation * operation)504 static void gb_loopback_async_operation_callback(struct gb_operation *operation)
505 {
506 struct gb_loopback_async_operation *op_async;
507 struct gb_loopback *gb;
508 struct timeval te;
509 bool err = false;
510
511 do_gettimeofday(&te);
512 op_async = gb_loopback_operation_find(operation->id);
513 if (!op_async)
514 return;
515
516 gb = op_async->gb;
517 mutex_lock(&gb->mutex);
518
519 if (!op_async->pending || gb_operation_result(operation)) {
520 err = true;
521 } else {
522 if (op_async->completion)
523 if (op_async->completion(op_async))
524 err = true;
525 }
526
527 if (!err) {
528 gb_loopback_push_latency_ts(gb, &op_async->ts, &te);
529 gb->elapsed_nsecs = gb_loopback_calc_latency(&op_async->ts,
530 &te);
531 }
532
533 if (op_async->pending) {
534 if (err)
535 gb->error++;
536 gb->iteration_count++;
537 op_async->pending = false;
538 del_timer_sync(&op_async->timer);
539 gb_loopback_async_operation_put(op_async);
540 gb_loopback_calculate_stats(gb, err);
541 }
542 mutex_unlock(&gb->mutex);
543
544 dev_dbg(&gb->connection->bundle->dev, "complete operation %d\n",
545 operation->id);
546
547 gb_loopback_async_operation_put(op_async);
548 }
549
gb_loopback_async_operation_work(struct work_struct * work)550 static void gb_loopback_async_operation_work(struct work_struct *work)
551 {
552 struct gb_loopback *gb;
553 struct gb_operation *operation;
554 struct gb_loopback_async_operation *op_async;
555
556 op_async = container_of(work, struct gb_loopback_async_operation, work);
557 gb = op_async->gb;
558 operation = op_async->operation;
559
560 mutex_lock(&gb->mutex);
561 if (op_async->pending) {
562 gb->requests_timedout++;
563 gb->error++;
564 gb->iteration_count++;
565 op_async->pending = false;
566 gb_loopback_async_operation_put(op_async);
567 gb_loopback_calculate_stats(gb, true);
568 }
569 mutex_unlock(&gb->mutex);
570
571 dev_dbg(&gb->connection->bundle->dev, "timeout operation %d\n",
572 operation->id);
573
574 gb_operation_cancel(operation, -ETIMEDOUT);
575 gb_loopback_async_operation_put(op_async);
576 }
577
gb_loopback_async_operation_timeout(unsigned long data)578 static void gb_loopback_async_operation_timeout(unsigned long data)
579 {
580 struct gb_loopback_async_operation *op_async;
581 u16 id = data;
582
583 op_async = gb_loopback_operation_find(id);
584 if (!op_async) {
585 pr_err("operation %d not found - time out ?\n", id);
586 return;
587 }
588 schedule_work(&op_async->work);
589 }
590
gb_loopback_async_operation(struct gb_loopback * gb,int type,void * request,int request_size,int response_size,void * completion)591 static int gb_loopback_async_operation(struct gb_loopback *gb, int type,
592 void *request, int request_size,
593 int response_size,
594 void *completion)
595 {
596 struct gb_loopback_async_operation *op_async;
597 struct gb_operation *operation;
598 int ret;
599 unsigned long flags;
600
601 op_async = kzalloc(sizeof(*op_async), GFP_KERNEL);
602 if (!op_async)
603 return -ENOMEM;
604
605 INIT_WORK(&op_async->work, gb_loopback_async_operation_work);
606 kref_init(&op_async->kref);
607
608 operation = gb_operation_create(gb->connection, type, request_size,
609 response_size, GFP_KERNEL);
610 if (!operation) {
611 kfree(op_async);
612 return -ENOMEM;
613 }
614
615 if (request_size)
616 memcpy(operation->request->payload, request, request_size);
617
618 op_async->gb = gb;
619 op_async->operation = operation;
620 op_async->completion = completion;
621
622 spin_lock_irqsave(&gb_dev.lock, flags);
623 list_add_tail(&op_async->entry, &gb_dev.list_op_async);
624 spin_unlock_irqrestore(&gb_dev.lock, flags);
625
626 do_gettimeofday(&op_async->ts);
627 op_async->pending = true;
628 atomic_inc(&gb->outstanding_operations);
629 mutex_lock(&gb->mutex);
630 ret = gb_operation_request_send(operation,
631 gb_loopback_async_operation_callback,
632 GFP_KERNEL);
633 if (ret)
634 goto error;
635
636 setup_timer(&op_async->timer, gb_loopback_async_operation_timeout,
637 (unsigned long)operation->id);
638 op_async->timer.expires = jiffies + gb->jiffy_timeout;
639 add_timer(&op_async->timer);
640
641 goto done;
642 error:
643 gb_loopback_async_operation_put(op_async);
644 done:
645 mutex_unlock(&gb->mutex);
646 return ret;
647 }
648
gb_loopback_sync_sink(struct gb_loopback * gb,u32 len)649 static int gb_loopback_sync_sink(struct gb_loopback *gb, u32 len)
650 {
651 struct gb_loopback_transfer_request *request;
652 int retval;
653
654 request = kmalloc(len + sizeof(*request), GFP_KERNEL);
655 if (!request)
656 return -ENOMEM;
657
658 request->len = cpu_to_le32(len);
659 retval = gb_loopback_operation_sync(gb, GB_LOOPBACK_TYPE_SINK,
660 request, len + sizeof(*request),
661 NULL, 0);
662 kfree(request);
663 return retval;
664 }
665
gb_loopback_sync_transfer(struct gb_loopback * gb,u32 len)666 static int gb_loopback_sync_transfer(struct gb_loopback *gb, u32 len)
667 {
668 struct gb_loopback_transfer_request *request;
669 struct gb_loopback_transfer_response *response;
670 int retval;
671
672 gb->apbridge_latency_ts = 0;
673 gb->gbphy_latency_ts = 0;
674
675 request = kmalloc(len + sizeof(*request), GFP_KERNEL);
676 if (!request)
677 return -ENOMEM;
678 response = kmalloc(len + sizeof(*response), GFP_KERNEL);
679 if (!response) {
680 kfree(request);
681 return -ENOMEM;
682 }
683
684 memset(request->data, 0x5A, len);
685
686 request->len = cpu_to_le32(len);
687 retval = gb_loopback_operation_sync(gb, GB_LOOPBACK_TYPE_TRANSFER,
688 request, len + sizeof(*request),
689 response, len + sizeof(*response));
690 if (retval)
691 goto gb_error;
692
693 if (memcmp(request->data, response->data, len)) {
694 dev_err(&gb->connection->bundle->dev,
695 "Loopback Data doesn't match\n");
696 retval = -EREMOTEIO;
697 }
698 gb->apbridge_latency_ts = (u32)__le32_to_cpu(response->reserved0);
699 gb->gbphy_latency_ts = (u32)__le32_to_cpu(response->reserved1);
700
701 gb_error:
702 kfree(request);
703 kfree(response);
704
705 return retval;
706 }
707
gb_loopback_sync_ping(struct gb_loopback * gb)708 static int gb_loopback_sync_ping(struct gb_loopback *gb)
709 {
710 return gb_loopback_operation_sync(gb, GB_LOOPBACK_TYPE_PING,
711 NULL, 0, NULL, 0);
712 }
713
gb_loopback_async_sink(struct gb_loopback * gb,u32 len)714 static int gb_loopback_async_sink(struct gb_loopback *gb, u32 len)
715 {
716 struct gb_loopback_transfer_request *request;
717 int retval;
718
719 request = kmalloc(len + sizeof(*request), GFP_KERNEL);
720 if (!request)
721 return -ENOMEM;
722
723 request->len = cpu_to_le32(len);
724 retval = gb_loopback_async_operation(gb, GB_LOOPBACK_TYPE_SINK,
725 request, len + sizeof(*request),
726 0, NULL);
727 kfree(request);
728 return retval;
729 }
730
gb_loopback_async_transfer_complete(struct gb_loopback_async_operation * op_async)731 static int gb_loopback_async_transfer_complete(
732 struct gb_loopback_async_operation *op_async)
733 {
734 struct gb_loopback *gb;
735 struct gb_operation *operation;
736 struct gb_loopback_transfer_request *request;
737 struct gb_loopback_transfer_response *response;
738 size_t len;
739 int retval = 0;
740
741 gb = op_async->gb;
742 operation = op_async->operation;
743 request = operation->request->payload;
744 response = operation->response->payload;
745 len = le32_to_cpu(request->len);
746
747 if (memcmp(request->data, response->data, len)) {
748 dev_err(&gb->connection->bundle->dev,
749 "Loopback Data doesn't match operation id %d\n",
750 operation->id);
751 retval = -EREMOTEIO;
752 } else {
753 gb->apbridge_latency_ts =
754 (u32)__le32_to_cpu(response->reserved0);
755 gb->gbphy_latency_ts =
756 (u32)__le32_to_cpu(response->reserved1);
757 }
758
759 return retval;
760 }
761
gb_loopback_async_transfer(struct gb_loopback * gb,u32 len)762 static int gb_loopback_async_transfer(struct gb_loopback *gb, u32 len)
763 {
764 struct gb_loopback_transfer_request *request;
765 int retval, response_len;
766
767 request = kmalloc(len + sizeof(*request), GFP_KERNEL);
768 if (!request)
769 return -ENOMEM;
770
771 memset(request->data, 0x5A, len);
772
773 request->len = cpu_to_le32(len);
774 response_len = sizeof(struct gb_loopback_transfer_response);
775 retval = gb_loopback_async_operation(gb, GB_LOOPBACK_TYPE_TRANSFER,
776 request, len + sizeof(*request),
777 len + response_len,
778 gb_loopback_async_transfer_complete);
779 if (retval)
780 goto gb_error;
781
782 gb_error:
783 kfree(request);
784 return retval;
785 }
786
gb_loopback_async_ping(struct gb_loopback * gb)787 static int gb_loopback_async_ping(struct gb_loopback *gb)
788 {
789 return gb_loopback_async_operation(gb, GB_LOOPBACK_TYPE_PING,
790 NULL, 0, 0, NULL);
791 }
792
gb_loopback_request_handler(struct gb_operation * operation)793 static int gb_loopback_request_handler(struct gb_operation *operation)
794 {
795 struct gb_connection *connection = operation->connection;
796 struct gb_loopback_transfer_request *request;
797 struct gb_loopback_transfer_response *response;
798 struct device *dev = &connection->bundle->dev;
799 size_t len;
800
801 /* By convention, the AP initiates the version operation */
802 switch (operation->type) {
803 case GB_LOOPBACK_TYPE_PING:
804 case GB_LOOPBACK_TYPE_SINK:
805 return 0;
806 case GB_LOOPBACK_TYPE_TRANSFER:
807 if (operation->request->payload_size < sizeof(*request)) {
808 dev_err(dev, "transfer request too small (%zu < %zu)\n",
809 operation->request->payload_size,
810 sizeof(*request));
811 return -EINVAL; /* -EMSGSIZE */
812 }
813 request = operation->request->payload;
814 len = le32_to_cpu(request->len);
815 if (len > gb_dev.size_max) {
816 dev_err(dev, "transfer request too large (%zu > %zu)\n",
817 len, gb_dev.size_max);
818 return -EINVAL;
819 }
820
821 if (!gb_operation_response_alloc(operation,
822 len + sizeof(*response), GFP_KERNEL)) {
823 dev_err(dev, "error allocating response\n");
824 return -ENOMEM;
825 }
826 response = operation->response->payload;
827 response->len = cpu_to_le32(len);
828 if (len)
829 memcpy(response->data, request->data, len);
830
831 return 0;
832 default:
833 dev_err(dev, "unsupported request: %u\n", operation->type);
834 return -EINVAL;
835 }
836 }
837
gb_loopback_reset_stats(struct gb_loopback * gb)838 static void gb_loopback_reset_stats(struct gb_loopback *gb)
839 {
840 struct gb_loopback_stats reset = {
841 .min = U32_MAX,
842 };
843
844 /* Reset per-connection stats */
845 memcpy(&gb->latency, &reset,
846 sizeof(struct gb_loopback_stats));
847 memcpy(&gb->throughput, &reset,
848 sizeof(struct gb_loopback_stats));
849 memcpy(&gb->requests_per_second, &reset,
850 sizeof(struct gb_loopback_stats));
851 memcpy(&gb->apbridge_unipro_latency, &reset,
852 sizeof(struct gb_loopback_stats));
853 memcpy(&gb->gbphy_firmware_latency, &reset,
854 sizeof(struct gb_loopback_stats));
855
856 /* Should be initialized at least once per transaction set */
857 gb->apbridge_latency_ts = 0;
858 gb->gbphy_latency_ts = 0;
859 memset(&gb->ts, 0, sizeof(struct timeval));
860 }
861
gb_loopback_update_stats(struct gb_loopback_stats * stats,u32 val)862 static void gb_loopback_update_stats(struct gb_loopback_stats *stats, u32 val)
863 {
864 if (stats->min > val)
865 stats->min = val;
866 if (stats->max < val)
867 stats->max = val;
868 stats->sum += val;
869 stats->count++;
870 }
871
gb_loopback_update_stats_window(struct gb_loopback_stats * stats,u64 val,u32 count)872 static void gb_loopback_update_stats_window(struct gb_loopback_stats *stats,
873 u64 val, u32 count)
874 {
875 stats->sum += val;
876 stats->count += count;
877
878 do_div(val, count);
879 if (stats->min > val)
880 stats->min = val;
881 if (stats->max < val)
882 stats->max = val;
883 }
884
gb_loopback_requests_update(struct gb_loopback * gb,u32 latency)885 static void gb_loopback_requests_update(struct gb_loopback *gb, u32 latency)
886 {
887 u64 req = gb->requests_completed * USEC_PER_SEC;
888
889 gb_loopback_update_stats_window(&gb->requests_per_second, req, latency);
890 }
891
gb_loopback_throughput_update(struct gb_loopback * gb,u32 latency)892 static void gb_loopback_throughput_update(struct gb_loopback *gb, u32 latency)
893 {
894 u64 aggregate_size = sizeof(struct gb_operation_msg_hdr) * 2;
895
896 switch (gb->type) {
897 case GB_LOOPBACK_TYPE_PING:
898 break;
899 case GB_LOOPBACK_TYPE_SINK:
900 aggregate_size += sizeof(struct gb_loopback_transfer_request) +
901 gb->size;
902 break;
903 case GB_LOOPBACK_TYPE_TRANSFER:
904 aggregate_size += sizeof(struct gb_loopback_transfer_request) +
905 sizeof(struct gb_loopback_transfer_response) +
906 gb->size * 2;
907 break;
908 default:
909 return;
910 }
911
912 aggregate_size *= gb->requests_completed;
913 aggregate_size *= USEC_PER_SEC;
914 gb_loopback_update_stats_window(&gb->throughput, aggregate_size,
915 latency);
916 }
917
gb_loopback_calculate_latency_stats(struct gb_loopback * gb)918 static void gb_loopback_calculate_latency_stats(struct gb_loopback *gb)
919 {
920 u32 lat;
921
922 /* Express latency in terms of microseconds */
923 lat = gb_loopback_nsec_to_usec_latency(gb->elapsed_nsecs);
924
925 /* Log latency stastic */
926 gb_loopback_update_stats(&gb->latency, lat);
927
928 /* Raw latency log on a per thread basis */
929 kfifo_in(&gb->kfifo_lat, (unsigned char *)&lat, sizeof(lat));
930
931 /* Log the firmware supplied latency values */
932 gb_loopback_update_stats(&gb->apbridge_unipro_latency,
933 gb->apbridge_latency_ts);
934 gb_loopback_update_stats(&gb->gbphy_firmware_latency,
935 gb->gbphy_latency_ts);
936 }
937
gb_loopback_calculate_stats(struct gb_loopback * gb,bool error)938 static void gb_loopback_calculate_stats(struct gb_loopback *gb, bool error)
939 {
940 u64 nlat;
941 u32 lat;
942 struct timeval te;
943
944 if (!error) {
945 gb->requests_completed++;
946 gb_loopback_calculate_latency_stats(gb);
947 }
948
949 do_gettimeofday(&te);
950 nlat = gb_loopback_calc_latency(&gb->ts, &te);
951 if (nlat >= NSEC_PER_SEC || gb->iteration_count == gb->iteration_max) {
952 lat = gb_loopback_nsec_to_usec_latency(nlat);
953
954 gb_loopback_throughput_update(gb, lat);
955 gb_loopback_requests_update(gb, lat);
956
957 if (gb->iteration_count != gb->iteration_max) {
958 gb->ts = te;
959 gb->requests_completed = 0;
960 }
961 }
962 }
963
gb_loopback_async_wait_to_send(struct gb_loopback * gb)964 static void gb_loopback_async_wait_to_send(struct gb_loopback *gb)
965 {
966 if (!(gb->async && gb->outstanding_operations_max))
967 return;
968 wait_event_interruptible(gb->wq_completion,
969 (atomic_read(&gb->outstanding_operations) <
970 gb->outstanding_operations_max) ||
971 kthread_should_stop());
972 }
973
gb_loopback_fn(void * data)974 static int gb_loopback_fn(void *data)
975 {
976 int error = 0;
977 int us_wait = 0;
978 int type;
979 int ret;
980 u32 size;
981
982 struct gb_loopback *gb = data;
983 struct gb_bundle *bundle = gb->connection->bundle;
984
985 ret = gb_pm_runtime_get_sync(bundle);
986 if (ret)
987 return ret;
988
989 while (1) {
990 if (!gb->type) {
991 gb_pm_runtime_put_autosuspend(bundle);
992 wait_event_interruptible(gb->wq, gb->type ||
993 kthread_should_stop());
994 ret = gb_pm_runtime_get_sync(bundle);
995 if (ret)
996 return ret;
997 }
998
999 if (kthread_should_stop())
1000 break;
1001
1002 /* Limit the maximum number of in-flight async operations */
1003 gb_loopback_async_wait_to_send(gb);
1004 if (kthread_should_stop())
1005 break;
1006
1007 mutex_lock(&gb->mutex);
1008
1009 /* Optionally terminate */
1010 if (gb->send_count == gb->iteration_max) {
1011 if (gb->iteration_count == gb->iteration_max) {
1012 gb->type = 0;
1013 gb->send_count = 0;
1014 sysfs_notify(&gb->dev->kobj, NULL,
1015 "iteration_count");
1016 }
1017 mutex_unlock(&gb->mutex);
1018 continue;
1019 }
1020 size = gb->size;
1021 us_wait = gb->us_wait;
1022 type = gb->type;
1023 if (gb->ts.tv_usec == 0 && gb->ts.tv_sec == 0)
1024 do_gettimeofday(&gb->ts);
1025 mutex_unlock(&gb->mutex);
1026
1027 /* Else operations to perform */
1028 if (gb->async) {
1029 if (type == GB_LOOPBACK_TYPE_PING) {
1030 error = gb_loopback_async_ping(gb);
1031 } else if (type == GB_LOOPBACK_TYPE_TRANSFER) {
1032 error = gb_loopback_async_transfer(gb, size);
1033 } else if (type == GB_LOOPBACK_TYPE_SINK) {
1034 error = gb_loopback_async_sink(gb, size);
1035 }
1036
1037 if (error) {
1038 gb->error++;
1039 gb->iteration_count++;
1040 }
1041 } else {
1042 /* We are effectively single threaded here */
1043 if (type == GB_LOOPBACK_TYPE_PING)
1044 error = gb_loopback_sync_ping(gb);
1045 else if (type == GB_LOOPBACK_TYPE_TRANSFER)
1046 error = gb_loopback_sync_transfer(gb, size);
1047 else if (type == GB_LOOPBACK_TYPE_SINK)
1048 error = gb_loopback_sync_sink(gb, size);
1049
1050 if (error)
1051 gb->error++;
1052 gb->iteration_count++;
1053 gb_loopback_calculate_stats(gb, !!error);
1054 }
1055 gb->send_count++;
1056
1057 if (us_wait) {
1058 if (us_wait < 20000)
1059 usleep_range(us_wait, us_wait + 100);
1060 else
1061 msleep(us_wait / 1000);
1062 }
1063 }
1064
1065 gb_pm_runtime_put_autosuspend(bundle);
1066
1067 return 0;
1068 }
1069
gb_loopback_dbgfs_latency_show_common(struct seq_file * s,struct kfifo * kfifo,struct mutex * mutex)1070 static int gb_loopback_dbgfs_latency_show_common(struct seq_file *s,
1071 struct kfifo *kfifo,
1072 struct mutex *mutex)
1073 {
1074 u32 latency;
1075 int retval;
1076
1077 if (kfifo_len(kfifo) == 0) {
1078 retval = -EAGAIN;
1079 goto done;
1080 }
1081
1082 mutex_lock(mutex);
1083 retval = kfifo_out(kfifo, &latency, sizeof(latency));
1084 if (retval > 0) {
1085 seq_printf(s, "%u", latency);
1086 retval = 0;
1087 }
1088 mutex_unlock(mutex);
1089 done:
1090 return retval;
1091 }
1092
gb_loopback_dbgfs_latency_show(struct seq_file * s,void * unused)1093 static int gb_loopback_dbgfs_latency_show(struct seq_file *s, void *unused)
1094 {
1095 struct gb_loopback *gb = s->private;
1096
1097 return gb_loopback_dbgfs_latency_show_common(s, &gb->kfifo_lat,
1098 &gb->mutex);
1099 }
1100
gb_loopback_latency_open(struct inode * inode,struct file * file)1101 static int gb_loopback_latency_open(struct inode *inode, struct file *file)
1102 {
1103 return single_open(file, gb_loopback_dbgfs_latency_show,
1104 inode->i_private);
1105 }
1106
1107 static const struct file_operations gb_loopback_debugfs_latency_ops = {
1108 .open = gb_loopback_latency_open,
1109 .read = seq_read,
1110 .llseek = seq_lseek,
1111 .release = single_release,
1112 };
1113
gb_loopback_bus_id_compare(void * priv,struct list_head * lha,struct list_head * lhb)1114 static int gb_loopback_bus_id_compare(void *priv, struct list_head *lha,
1115 struct list_head *lhb)
1116 {
1117 struct gb_loopback *a = list_entry(lha, struct gb_loopback, entry);
1118 struct gb_loopback *b = list_entry(lhb, struct gb_loopback, entry);
1119 struct gb_connection *ca = a->connection;
1120 struct gb_connection *cb = b->connection;
1121
1122 if (ca->bundle->intf->interface_id < cb->bundle->intf->interface_id)
1123 return -1;
1124 if (cb->bundle->intf->interface_id < ca->bundle->intf->interface_id)
1125 return 1;
1126 if (ca->bundle->id < cb->bundle->id)
1127 return -1;
1128 if (cb->bundle->id < ca->bundle->id)
1129 return 1;
1130 if (ca->intf_cport_id < cb->intf_cport_id)
1131 return -1;
1132 else if (cb->intf_cport_id < ca->intf_cport_id)
1133 return 1;
1134
1135 return 0;
1136 }
1137
gb_loopback_insert_id(struct gb_loopback * gb)1138 static void gb_loopback_insert_id(struct gb_loopback *gb)
1139 {
1140 struct gb_loopback *gb_list;
1141 u32 new_lbid = 0;
1142
1143 /* perform an insertion sort */
1144 list_add_tail(&gb->entry, &gb_dev.list);
1145 list_sort(NULL, &gb_dev.list, gb_loopback_bus_id_compare);
1146 list_for_each_entry(gb_list, &gb_dev.list, entry) {
1147 gb_list->lbid = 1 << new_lbid;
1148 new_lbid++;
1149 }
1150 }
1151
1152 #define DEBUGFS_NAMELEN 32
1153
gb_loopback_probe(struct gb_bundle * bundle,const struct greybus_bundle_id * id)1154 static int gb_loopback_probe(struct gb_bundle *bundle,
1155 const struct greybus_bundle_id *id)
1156 {
1157 struct greybus_descriptor_cport *cport_desc;
1158 struct gb_connection *connection;
1159 struct gb_loopback *gb;
1160 struct device *dev;
1161 int retval;
1162 char name[DEBUGFS_NAMELEN];
1163 unsigned long flags;
1164
1165 if (bundle->num_cports != 1)
1166 return -ENODEV;
1167
1168 cport_desc = &bundle->cport_desc[0];
1169 if (cport_desc->protocol_id != GREYBUS_PROTOCOL_LOOPBACK)
1170 return -ENODEV;
1171
1172 gb = kzalloc(sizeof(*gb), GFP_KERNEL);
1173 if (!gb)
1174 return -ENOMEM;
1175
1176 connection = gb_connection_create(bundle, le16_to_cpu(cport_desc->id),
1177 gb_loopback_request_handler);
1178 if (IS_ERR(connection)) {
1179 retval = PTR_ERR(connection);
1180 goto out_kzalloc;
1181 }
1182
1183 gb->connection = connection;
1184 greybus_set_drvdata(bundle, gb);
1185
1186 init_waitqueue_head(&gb->wq);
1187 init_waitqueue_head(&gb->wq_completion);
1188 atomic_set(&gb->outstanding_operations, 0);
1189 gb_loopback_reset_stats(gb);
1190
1191 /* Reported values to user-space for min/max timeouts */
1192 gb->timeout_min = jiffies_to_usecs(GB_LOOPBACK_TIMEOUT_MIN);
1193 gb->timeout_max = jiffies_to_usecs(GB_LOOPBACK_TIMEOUT_MAX);
1194
1195 if (!gb_dev.count) {
1196 /* Calculate maximum payload */
1197 gb_dev.size_max = gb_operation_get_payload_size_max(connection);
1198 if (gb_dev.size_max <=
1199 sizeof(struct gb_loopback_transfer_request)) {
1200 retval = -EINVAL;
1201 goto out_connection_destroy;
1202 }
1203 gb_dev.size_max -= sizeof(struct gb_loopback_transfer_request);
1204 }
1205
1206 /* Create per-connection sysfs and debugfs data-points */
1207 snprintf(name, sizeof(name), "raw_latency_%s",
1208 dev_name(&connection->bundle->dev));
1209 gb->file = debugfs_create_file(name, S_IFREG | S_IRUGO, gb_dev.root, gb,
1210 &gb_loopback_debugfs_latency_ops);
1211
1212 gb->id = ida_simple_get(&loopback_ida, 0, 0, GFP_KERNEL);
1213 if (gb->id < 0) {
1214 retval = gb->id;
1215 goto out_debugfs_remove;
1216 }
1217
1218 retval = gb_connection_enable(connection);
1219 if (retval)
1220 goto out_ida_remove;
1221
1222 dev = device_create_with_groups(&loopback_class,
1223 &connection->bundle->dev,
1224 MKDEV(0, 0), gb, loopback_groups,
1225 "gb_loopback%d", gb->id);
1226 if (IS_ERR(dev)) {
1227 retval = PTR_ERR(dev);
1228 goto out_connection_disable;
1229 }
1230 gb->dev = dev;
1231
1232 /* Allocate kfifo */
1233 if (kfifo_alloc(&gb->kfifo_lat, kfifo_depth * sizeof(u32),
1234 GFP_KERNEL)) {
1235 retval = -ENOMEM;
1236 goto out_conn;
1237 }
1238 if (kfifo_alloc(&gb->kfifo_ts, kfifo_depth * sizeof(struct timeval) * 2,
1239 GFP_KERNEL)) {
1240 retval = -ENOMEM;
1241 goto out_kfifo0;
1242 }
1243
1244 /* Fork worker thread */
1245 mutex_init(&gb->mutex);
1246 gb->task = kthread_run(gb_loopback_fn, gb, "gb_loopback");
1247 if (IS_ERR(gb->task)) {
1248 retval = PTR_ERR(gb->task);
1249 goto out_kfifo1;
1250 }
1251
1252 spin_lock_irqsave(&gb_dev.lock, flags);
1253 gb_loopback_insert_id(gb);
1254 gb_dev.count++;
1255 spin_unlock_irqrestore(&gb_dev.lock, flags);
1256
1257 gb_connection_latency_tag_enable(connection);
1258
1259 gb_pm_runtime_put_autosuspend(bundle);
1260
1261 return 0;
1262
1263 out_kfifo1:
1264 kfifo_free(&gb->kfifo_ts);
1265 out_kfifo0:
1266 kfifo_free(&gb->kfifo_lat);
1267 out_conn:
1268 device_unregister(dev);
1269 out_connection_disable:
1270 gb_connection_disable(connection);
1271 out_ida_remove:
1272 ida_simple_remove(&loopback_ida, gb->id);
1273 out_debugfs_remove:
1274 debugfs_remove(gb->file);
1275 out_connection_destroy:
1276 gb_connection_destroy(connection);
1277 out_kzalloc:
1278 kfree(gb);
1279
1280 return retval;
1281 }
1282
gb_loopback_disconnect(struct gb_bundle * bundle)1283 static void gb_loopback_disconnect(struct gb_bundle *bundle)
1284 {
1285 struct gb_loopback *gb = greybus_get_drvdata(bundle);
1286 unsigned long flags;
1287 int ret;
1288
1289 ret = gb_pm_runtime_get_sync(bundle);
1290 if (ret)
1291 gb_pm_runtime_get_noresume(bundle);
1292
1293 gb_connection_disable(gb->connection);
1294
1295 if (!IS_ERR_OR_NULL(gb->task))
1296 kthread_stop(gb->task);
1297
1298 kfifo_free(&gb->kfifo_lat);
1299 kfifo_free(&gb->kfifo_ts);
1300 gb_connection_latency_tag_disable(gb->connection);
1301 debugfs_remove(gb->file);
1302
1303 /*
1304 * FIXME: gb_loopback_async_wait_all() is redundant now, as connection
1305 * is disabled at the beginning and so we can't have any more
1306 * incoming/outgoing requests.
1307 */
1308 gb_loopback_async_wait_all(gb);
1309
1310 spin_lock_irqsave(&gb_dev.lock, flags);
1311 gb_dev.count--;
1312 list_del(&gb->entry);
1313 spin_unlock_irqrestore(&gb_dev.lock, flags);
1314
1315 device_unregister(gb->dev);
1316 ida_simple_remove(&loopback_ida, gb->id);
1317
1318 gb_connection_destroy(gb->connection);
1319 kfree(gb);
1320 }
1321
1322 static const struct greybus_bundle_id gb_loopback_id_table[] = {
1323 { GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_LOOPBACK) },
1324 { }
1325 };
1326 MODULE_DEVICE_TABLE(greybus, gb_loopback_id_table);
1327
1328 static struct greybus_driver gb_loopback_driver = {
1329 .name = "loopback",
1330 .probe = gb_loopback_probe,
1331 .disconnect = gb_loopback_disconnect,
1332 .id_table = gb_loopback_id_table,
1333 };
1334
loopback_init(void)1335 static int loopback_init(void)
1336 {
1337 int retval;
1338
1339 INIT_LIST_HEAD(&gb_dev.list);
1340 INIT_LIST_HEAD(&gb_dev.list_op_async);
1341 spin_lock_init(&gb_dev.lock);
1342 gb_dev.root = debugfs_create_dir("gb_loopback", NULL);
1343
1344 retval = class_register(&loopback_class);
1345 if (retval)
1346 goto err;
1347
1348 retval = greybus_register(&gb_loopback_driver);
1349 if (retval)
1350 goto err_unregister;
1351
1352 return 0;
1353
1354 err_unregister:
1355 class_unregister(&loopback_class);
1356 err:
1357 debugfs_remove_recursive(gb_dev.root);
1358 return retval;
1359 }
1360 module_init(loopback_init);
1361
loopback_exit(void)1362 static void __exit loopback_exit(void)
1363 {
1364 debugfs_remove_recursive(gb_dev.root);
1365 greybus_deregister(&gb_loopback_driver);
1366 class_unregister(&loopback_class);
1367 ida_destroy(&loopback_ida);
1368 }
1369 module_exit(loopback_exit);
1370
1371 MODULE_LICENSE("GPL v2");
1372