drivers/staging/greybus/loopback.c

   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 int 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);
 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
 366 static u32 gb_loopback_nsec_to_usec_latency(u64 elapsed_nsecs)
 367 {
 368         do_div(elapsed_nsecs, NSEC_PER_USEC);
 369         return elapsed_nsecs;
 370 }
 371
 372 static u64 __gb_loopback_calc_latency(u64 t1, u64 t2)
 373 {
 374         if (t2 > t1)
 375                 return t2 - t1;
 376         else
 377                 return NSEC_PER_DAY - t2 + t1;
 378 }
 379
 380 static u64 gb_loopback_calc_latency(struct timeval *ts, struct timeval *te)
 381 {
 382         u64 t1, t2;
 383
 384         t1 = timeval_to_ns(ts);
 385         t2 = timeval_to_ns(te);
 386
 387         return __gb_loopback_calc_latency(t1, t2);
 388 }
 389
 390 static void gb_loopback_push_latency_ts(struct gb_loopback *gb,
 391                                         struct timeval *ts, struct timeval *te)
 392 {
 393         kfifo_in(&gb->kfifo_ts, (unsigned char *)ts, sizeof(*ts));
 394         kfifo_in(&gb->kfifo_ts, (unsigned char *)te, sizeof(*te));
 395 }
 396
 397 static int gb_loopback_operation_sync(struct gb_loopback *gb, int type,
 398                                       void *request, int request_size,
 399                                       void *response, int response_size)
 400 {
 401         struct gb_operation *operation;
 402         struct timeval ts, te;
 403         int ret;
 404
 405         do_gettimeofday(&ts);
 406         operation = gb_operation_create(gb->connection, type, request_size,
 407                                         response_size, GFP_KERNEL);
 408         if (!operation)
 409                 return -ENOMEM;
 410
 411         if (request_size)
 412                 memcpy(operation->request->payload, request, request_size);
 413
 414         ret = gb_operation_request_send_sync(operation);
 415         if (ret) {
 416                 dev_err(&gb->connection->bundle->dev,
 417                         "synchronous operation failed: %d\n", ret);
 418                 goto out_put_operation;
 419         } else {
 420                 if (response_size == operation->response->payload_size) {
 421                         memcpy(response, operation->response->payload,
 422                                response_size);
 423                 } else {
 424                         dev_err(&gb->connection->bundle->dev,
 425                                 "response size %zu expected %d\n",
 426                                 operation->response->payload_size,
 427                                 response_size);
 428                         ret = -EINVAL;
 429                         goto out_put_operation;
 430                 }
 431         }
 432
 433         do_gettimeofday(&te);
 434
 435         /* Calculate the total time the message took */
 436         gb_loopback_push_latency_ts(gb, &ts, &te);
 437         gb->elapsed_nsecs = gb_loopback_calc_latency(&ts, &te);
 438
 439 out_put_operation:
 440         gb_operation_put(operation);
 441
 442         return ret;
 443 }
 444
 445 static void __gb_loopback_async_operation_destroy(struct kref *kref)
 446 {
 447         struct gb_loopback_async_operation *op_async;
 448
 449         op_async = container_of(kref, struct gb_loopback_async_operation, kref);
 450
 451         list_del(&op_async->entry);
 452         if (op_async->operation)
 453                 gb_operation_put(op_async->operation);
 454         atomic_dec(&op_async->gb->outstanding_operations);
 455         wake_up(&op_async->gb->wq_completion);
 456         kfree(op_async);
 457 }
 458
 459 static void gb_loopback_async_operation_get(struct gb_loopback_async_operation
 460                                             *op_async)
 461 {
 462         kref_get(&op_async->kref);
 463 }
 464
 465 static void gb_loopback_async_operation_put(struct gb_loopback_async_operation
 466                                             *op_async)
 467 {
 468         unsigned long flags;
 469
 470         spin_lock_irqsave(&gb_dev.lock, flags);
 471         kref_put(&op_async->kref, __gb_loopback_async_operation_destroy);
 472         spin_unlock_irqrestore(&gb_dev.lock, flags);
 473 }
 474
 475 static struct gb_loopback_async_operation *
 476         gb_loopback_operation_find(u16 id)
 477 {
 478         struct gb_loopback_async_operation *op_async;
 479         bool found = false;
 480         unsigned long flags;
 481
 482         spin_lock_irqsave(&gb_dev.lock, flags);
 483         list_for_each_entry(op_async, &gb_dev.list_op_async, entry) {
 484                 if (op_async->operation->id == id) {
 485                         gb_loopback_async_operation_get(op_async);
 486                         found = true;
 487                         break;
 488                 }
 489         }
 490         spin_unlock_irqrestore(&gb_dev.lock, flags);
 491
 492         return found ? op_async : NULL;
 493 }
 494
 495 static void gb_loopback_async_wait_all(struct gb_loopback *gb)
 496 {
 497         wait_event(gb->wq_completion,
 498                    !atomic_read(&gb->outstanding_operations));
 499 }
 500
 501 static void gb_loopback_async_operation_callback(struct gb_operation *operation)
 502 {
 503         struct gb_loopback_async_operation *op_async;
 504         struct gb_loopback *gb;
 505         struct timeval te;
 506         bool err = false;
 507
 508         do_gettimeofday(&te);
 509         op_async = gb_loopback_operation_find(operation->id);
 510         if (!op_async)
 511                 return;
 512
 513         gb = op_async->gb;
 514         mutex_lock(&gb->mutex);
 515
 516         if (!op_async->pending || gb_operation_result(operation)) {
 517                 err = true;
 518         } else {
 519                 if (op_async->completion)
 520                         if (op_async->completion(op_async))
 521                                 err = true;
 522         }
 523
 524         if (!err) {
 525                 gb_loopback_push_latency_ts(gb, &op_async->ts, &te);
 526                 gb->elapsed_nsecs = gb_loopback_calc_latency(&op_async->ts,
 527                                                              &te);
 528         }
 529
 530         if (op_async->pending) {
 531                 if (err)
 532                         gb->error++;
 533                 gb->iteration_count++;
 534                 op_async->pending = false;
 535                 del_timer_sync(&op_async->timer);
 536                 gb_loopback_async_operation_put(op_async);
 537                 gb_loopback_calculate_stats(gb, err);
 538         }
 539         mutex_unlock(&gb->mutex);
 540
 541         dev_dbg(&gb->connection->bundle->dev, "complete operation %d\n",
 542                 operation->id);
 543
 544         gb_loopback_async_operation_put(op_async);
 545 }
 546
 547 static void gb_loopback_async_operation_work(struct work_struct *work)
 548 {
 549         struct gb_loopback *gb;
 550         struct gb_operation *operation;
 551         struct gb_loopback_async_operation *op_async;
 552
 553         op_async = container_of(work, struct gb_loopback_async_operation, work);
 554         gb = op_async->gb;
 555         operation = op_async->operation;
 556
 557         mutex_lock(&gb->mutex);
 558         if (op_async->pending) {
 559                 gb->requests_timedout++;
 560                 gb->error++;
 561                 gb->iteration_count++;
 562                 op_async->pending = false;
 563                 gb_loopback_async_operation_put(op_async);
 564                 gb_loopback_calculate_stats(gb, true);
 565         }
 566         mutex_unlock(&gb->mutex);
 567
 568         dev_dbg(&gb->connection->bundle->dev, "timeout operation %d\n",
 569                 operation->id);
 570
 571         gb_operation_cancel(operation, -ETIMEDOUT);
 572         gb_loopback_async_operation_put(op_async);
 573 }
 574
 575 static void gb_loopback_async_operation_timeout(unsigned long data)
 576 {
 577         struct gb_loopback_async_operation *op_async;
 578         u16 id = data;
 579
 580         op_async = gb_loopback_operation_find(id);
 581         if (!op_async) {
 582                 pr_err("operation %d not found - time out ?\n", id);
 583                 return;
 584         }
 585         schedule_work(&op_async->work);
 586 }
 587
 588 static int gb_loopback_async_operation(struct gb_loopback *gb, int type,
 589                                        void *request, int request_size,
 590                                        int response_size,
 591                                        void *completion)
 592 {
 593         struct gb_loopback_async_operation *op_async;
 594         struct gb_operation *operation;
 595         int ret;
 596         unsigned long flags;
 597
 598         op_async = kzalloc(sizeof(*op_async), GFP_KERNEL);
 599         if (!op_async)
 600                 return -ENOMEM;
 601
 602         INIT_WORK(&op_async->work, gb_loopback_async_operation_work);
 603         kref_init(&op_async->kref);
 604
 605         operation = gb_operation_create(gb->connection, type, request_size,
 606                                         response_size, GFP_KERNEL);
 607         if (!operation) {
 608                 kfree(op_async);
 609                 return -ENOMEM;
 610         }
 611
 612         if (request_size)
 613                 memcpy(operation->request->payload, request, request_size);
 614
 615         op_async->gb = gb;
 616         op_async->operation = operation;
 617         op_async->completion = completion;
 618
 619         spin_lock_irqsave(&gb_dev.lock, flags);
 620         list_add_tail(&op_async->entry, &gb_dev.list_op_async);
 621         spin_unlock_irqrestore(&gb_dev.lock, flags);
 622
 623         do_gettimeofday(&op_async->ts);
 624         op_async->pending = true;
 625         atomic_inc(&gb->outstanding_operations);
 626         mutex_lock(&gb->mutex);
 627         ret = gb_operation_request_send(operation,
 628                                         gb_loopback_async_operation_callback,
 629                                         0,
 630                                         GFP_KERNEL);
 631         if (ret)
 632                 goto error;
 633
 634         setup_timer(&op_async->timer, gb_loopback_async_operation_timeout,
 635                         (unsigned long)operation->id);
 636         op_async->timer.expires = jiffies + gb->jiffy_timeout;
 637         add_timer(&op_async->timer);
 638
 639         goto done;
 640 error:
 641         gb_loopback_async_operation_put(op_async);
 642 done:
 643         mutex_unlock(&gb->mutex);
 644         return ret;
 645 }
 646
 647 static int gb_loopback_sync_sink(struct gb_loopback *gb, u32 len)
 648 {
 649         struct gb_loopback_transfer_request *request;
 650         int retval;
 651
 652         request = kmalloc(len + sizeof(*request), GFP_KERNEL);
 653         if (!request)
 654                 return -ENOMEM;
 655
 656         request->len = cpu_to_le32(len);
 657         retval = gb_loopback_operation_sync(gb, GB_LOOPBACK_TYPE_SINK,
 658                                             request, len + sizeof(*request),
 659                                             NULL, 0);
 660         kfree(request);
 661         return retval;
 662 }
 663
 664 static int gb_loopback_sync_transfer(struct gb_loopback *gb, u32 len)
 665 {
 666         struct gb_loopback_transfer_request *request;
 667         struct gb_loopback_transfer_response *response;
 668         int retval;
 669
 670         gb->apbridge_latency_ts = 0;
 671         gb->gbphy_latency_ts = 0;
 672
 673         request = kmalloc(len + sizeof(*request), GFP_KERNEL);
 674         if (!request)
 675                 return -ENOMEM;
 676         response = kmalloc(len + sizeof(*response), GFP_KERNEL);
 677         if (!response) {
 678                 kfree(request);
 679                 return -ENOMEM;
 680         }
 681
 682         memset(request->data, 0x5A, len);
 683
 684         request->len = cpu_to_le32(len);
 685         retval = gb_loopback_operation_sync(gb, GB_LOOPBACK_TYPE_TRANSFER,
 686                                             request, len + sizeof(*request),
 687                                             response, len + sizeof(*response));
 688         if (retval)
 689                 goto gb_error;
 690
 691         if (memcmp(request->data, response->data, len)) {
 692                 dev_err(&gb->connection->bundle->dev,
 693                         "Loopback Data doesn't match\n");
 694                 retval = -EREMOTEIO;
 695         }
 696         gb->apbridge_latency_ts = (u32)__le32_to_cpu(response->reserved0);
 697         gb->gbphy_latency_ts = (u32)__le32_to_cpu(response->reserved1);
 698
 699 gb_error:
 700         kfree(request);
 701         kfree(response);
 702
 703         return retval;
 704 }
 705
 706 static int gb_loopback_sync_ping(struct gb_loopback *gb)
 707 {
 708         return gb_loopback_operation_sync(gb, GB_LOOPBACK_TYPE_PING,
 709                                           NULL, 0, NULL, 0);
 710 }
 711
 712 static int gb_loopback_async_sink(struct gb_loopback *gb, u32 len)
 713 {
 714         struct gb_loopback_transfer_request *request;
 715         int retval;
 716
 717         request = kmalloc(len + sizeof(*request), GFP_KERNEL);
 718         if (!request)
 719                 return -ENOMEM;
 720
 721         request->len = cpu_to_le32(len);
 722         retval = gb_loopback_async_operation(gb, GB_LOOPBACK_TYPE_SINK,
 723                                              request, len + sizeof(*request),
 724                                              0, NULL);
 725         kfree(request);
 726         return retval;
 727 }
 728
 729 static int gb_loopback_async_transfer_complete(
 730                                 struct gb_loopback_async_operation *op_async)
 731 {
 732         struct gb_loopback *gb;
 733         struct gb_operation *operation;
 734         struct gb_loopback_transfer_request *request;
 735         struct gb_loopback_transfer_response *response;
 736         size_t len;
 737         int retval = 0;
 738
 739         gb = op_async->gb;
 740         operation = op_async->operation;
 741         request = operation->request->payload;
 742         response = operation->response->payload;
 743         len = le32_to_cpu(request->len);
 744
 745         if (memcmp(request->data, response->data, len)) {
 746                 dev_err(&gb->connection->bundle->dev,
 747                         "Loopback Data doesn't match operation id %d\n",
 748                         operation->id);
 749                 retval = -EREMOTEIO;
 750         } else {
 751                 gb->apbridge_latency_ts =
 752                         (u32)__le32_to_cpu(response->reserved0);
 753                 gb->gbphy_latency_ts =
 754                         (u32)__le32_to_cpu(response->reserved1);
 755         }
 756
 757         return retval;
 758 }
 759
 760 static int gb_loopback_async_transfer(struct gb_loopback *gb, u32 len)
 761 {
 762         struct gb_loopback_transfer_request *request;
 763         int retval, response_len;
 764
 765         request = kmalloc(len + sizeof(*request), GFP_KERNEL);
 766         if (!request)
 767                 return -ENOMEM;
 768
 769         memset(request->data, 0x5A, len);
 770
 771         request->len = cpu_to_le32(len);
 772         response_len = sizeof(struct gb_loopback_transfer_response);
 773         retval = gb_loopback_async_operation(gb, GB_LOOPBACK_TYPE_TRANSFER,
 774                                              request, len + sizeof(*request),
 775                                              len + response_len,
 776                                              gb_loopback_async_transfer_complete);
 777         if (retval)
 778                 goto gb_error;
 779
 780 gb_error:
 781         kfree(request);
 782         return retval;
 783 }
 784
 785 static int gb_loopback_async_ping(struct gb_loopback *gb)
 786 {
 787         return gb_loopback_async_operation(gb, GB_LOOPBACK_TYPE_PING,
 788                                            NULL, 0, 0, NULL);
 789 }
 790
 791 static int gb_loopback_request_handler(struct gb_operation *operation)
 792 {
 793         struct gb_connection *connection = operation->connection;
 794         struct gb_loopback_transfer_request *request;
 795         struct gb_loopback_transfer_response *response;
 796         struct device *dev = &connection->bundle->dev;
 797         size_t len;
 798
 799         /* By convention, the AP initiates the version operation */
 800         switch (operation->type) {
 801         case GB_LOOPBACK_TYPE_PING:
 802         case GB_LOOPBACK_TYPE_SINK:
 803                 return 0;
 804         case GB_LOOPBACK_TYPE_TRANSFER:
 805                 if (operation->request->payload_size < sizeof(*request)) {
 806                         dev_err(dev, "transfer request too small (%zu < %zu)\n",
 807                                 operation->request->payload_size,
 808                                 sizeof(*request));
 809                         return -EINVAL; /* -EMSGSIZE */
 810                 }
 811                 request = operation->request->payload;
 812                 len = le32_to_cpu(request->len);
 813                 if (len > gb_dev.size_max) {
 814                         dev_err(dev, "transfer request too large (%zu > %zu)\n",
 815                                 len, gb_dev.size_max);
 816                         return -EINVAL;
 817                 }
 818
 819                 if (!gb_operation_response_alloc(operation,
 820                                 len + sizeof(*response), GFP_KERNEL)) {
 821                         dev_err(dev, "error allocating response\n");
 822                         return -ENOMEM;
 823                 }
 824                 response = operation->response->payload;
 825                 response->len = cpu_to_le32(len);
 826                 if (len)
 827                         memcpy(response->data, request->data, len);
 828
 829                 return 0;
 830         default:
 831                 dev_err(dev, "unsupported request: %u\n", operation->type);
 832                 return -EINVAL;
 833         }
 834 }
 835
 836 static void gb_loopback_reset_stats(struct gb_loopback *gb)
 837 {
 838         struct gb_loopback_stats reset = {
 839                 .min = U32_MAX,
 840         };
 841
 842         /* Reset per-connection stats */
 843         memcpy(&gb->latency, &reset,
 844                sizeof(struct gb_loopback_stats));
 845         memcpy(&gb->throughput, &reset,
 846                sizeof(struct gb_loopback_stats));
 847         memcpy(&gb->requests_per_second, &reset,
 848                sizeof(struct gb_loopback_stats));
 849         memcpy(&gb->apbridge_unipro_latency, &reset,
 850                sizeof(struct gb_loopback_stats));
 851         memcpy(&gb->gbphy_firmware_latency, &reset,
 852                sizeof(struct gb_loopback_stats));
 853
 854         /* Should be initialized at least once per transaction set */
 855         gb->apbridge_latency_ts = 0;
 856         gb->gbphy_latency_ts = 0;
 857         memset(&gb->ts, 0, sizeof(struct timeval));
 858 }
 859
 860 static void gb_loopback_update_stats(struct gb_loopback_stats *stats, u32 val)
 861 {
 862         if (stats->min > val)
 863                 stats->min = val;
 864         if (stats->max < val)
 865                 stats->max = val;
 866         stats->sum += val;
 867         stats->count++;
 868 }
 869
 870 static void gb_loopback_update_stats_window(struct gb_loopback_stats *stats,
 871                                             u64 val, u32 count)
 872 {
 873         stats->sum += val;
 874         stats->count += count;
 875
 876         do_div(val, count);
 877         if (stats->min > val)
 878                 stats->min = val;
 879         if (stats->max < val)
 880                 stats->max = val;
 881 }
 882
 883 static void gb_loopback_requests_update(struct gb_loopback *gb, u32 latency)
 884 {
 885         u64 req = gb->requests_completed * USEC_PER_SEC;
 886
 887         gb_loopback_update_stats_window(&gb->requests_per_second, req, latency);
 888 }
 889
 890 static void gb_loopback_throughput_update(struct gb_loopback *gb, u32 latency)
 891 {
 892         u64 aggregate_size = sizeof(struct gb_operation_msg_hdr) * 2;
 893
 894         switch (gb->type) {
 895         case GB_LOOPBACK_TYPE_PING:
 896                 break;
 897         case GB_LOOPBACK_TYPE_SINK:
 898                 aggregate_size += sizeof(struct gb_loopback_transfer_request) +
 899                                   gb->size;
 900                 break;
 901         case GB_LOOPBACK_TYPE_TRANSFER:
 902                 aggregate_size += sizeof(struct gb_loopback_transfer_request) +
 903                                   sizeof(struct gb_loopback_transfer_response) +
 904                                   gb->size * 2;
 905                 break;
 906         default:
 907                 return;
 908         }
 909
 910         aggregate_size *= gb->requests_completed;
 911         aggregate_size *= USEC_PER_SEC;
 912         gb_loopback_update_stats_window(&gb->throughput, aggregate_size,
 913                                         latency);
 914 }
 915
 916 static void gb_loopback_calculate_latency_stats(struct gb_loopback *gb)
 917 {
 918         u32 lat;
 919
 920         /* Express latency in terms of microseconds */
 921         lat = gb_loopback_nsec_to_usec_latency(gb->elapsed_nsecs);
 922
 923         /* Log latency stastic */
 924         gb_loopback_update_stats(&gb->latency, lat);
 925
 926         /* Raw latency log on a per thread basis */
 927         kfifo_in(&gb->kfifo_lat, (unsigned char *)&lat, sizeof(lat));
 928
 929         /* Log the firmware supplied latency values */
 930         gb_loopback_update_stats(&gb->apbridge_unipro_latency,
 931                                  gb->apbridge_latency_ts);
 932         gb_loopback_update_stats(&gb->gbphy_firmware_latency,
 933                                  gb->gbphy_latency_ts);
 934 }
 935
 936 static void gb_loopback_calculate_stats(struct gb_loopback *gb, bool error)
 937 {
 938         u64 nlat;
 939         u32 lat;
 940         struct timeval te;
 941
 942         if (!error) {
 943                 gb->requests_completed++;
 944                 gb_loopback_calculate_latency_stats(gb);
 945         }
 946
 947         do_gettimeofday(&te);
 948         nlat = gb_loopback_calc_latency(&gb->ts, &te);
 949         if (nlat >= NSEC_PER_SEC || gb->iteration_count == gb->iteration_max) {
 950                 lat = gb_loopback_nsec_to_usec_latency(nlat);
 951
 952                 gb_loopback_throughput_update(gb, lat);
 953                 gb_loopback_requests_update(gb, lat);
 954
 955                 if (gb->iteration_count != gb->iteration_max) {
 956                         gb->ts = te;
 957                         gb->requests_completed = 0;
 958                 }
 959         }
 960 }
 961
 962 static void gb_loopback_async_wait_to_send(struct gb_loopback *gb)
 963 {
 964         if (!(gb->async && gb->outstanding_operations_max))
 965                 return;
 966         wait_event_interruptible(gb->wq_completion,
 967                                  (atomic_read(&gb->outstanding_operations) <
 968                                   gb->outstanding_operations_max) ||
 969                                   kthread_should_stop());
 970 }
 971
 972 static int gb_loopback_fn(void *data)
 973 {
 974         int error = 0;
 975         int us_wait = 0;
 976         int type;
 977         int ret;
 978         u32 size;
 979
 980         struct gb_loopback *gb = data;
 981         struct gb_bundle *bundle = gb->connection->bundle;
 982
 983         ret = gb_pm_runtime_get_sync(bundle);
 984         if (ret)
 985                 return ret;
 986
 987         while (1) {
 988                 if (!gb->type) {
 989                         gb_pm_runtime_put_autosuspend(bundle);
 990                         wait_event_interruptible(gb->wq, gb->type ||
 991                                                  kthread_should_stop());
 992                         ret = gb_pm_runtime_get_sync(bundle);
 993                         if (ret)
 994                                 return ret;
 995                 }
 996
 997                 if (kthread_should_stop())
 998                         break;
 999
1000                 /* Limit the maximum number of in-flight async operations */
1001                 gb_loopback_async_wait_to_send(gb);
1002                 if (kthread_should_stop())
1003                         break;
1004
1005                 mutex_lock(&gb->mutex);
1006
1007                 /* Optionally terminate */
1008                 if (gb->send_count == gb->iteration_max) {
1009                         mutex_unlock(&gb->mutex);
1010
1011                         /* Wait for synchronous and asynchronus completion */
1012                         gb_loopback_async_wait_all(gb);
1013
1014                         /* Mark complete unless user-space has poked us */
1015                         mutex_lock(&gb->mutex);
1016                         if (gb->iteration_count == gb->iteration_max) {
1017                                 gb->type = 0;
1018                                 gb->send_count = 0;
1019                                 sysfs_notify(&gb->dev->kobj,  NULL,
1020                                                 "iteration_count");
1021                                 dev_dbg(&bundle->dev, "load test complete\n");
1022                         } else {
1023                                 dev_dbg(&bundle->dev,
1024                                         "continuing on with new test set\n");
1025                         }
1026                         mutex_unlock(&gb->mutex);
1027                         continue;
1028                 }
1029                 size = gb->size;
1030                 us_wait = gb->us_wait;
1031                 type = gb->type;
1032                 if (gb->ts.tv_usec == 0 && gb->ts.tv_sec == 0)
1033                         do_gettimeofday(&gb->ts);
1034                 mutex_unlock(&gb->mutex);
1035
1036                 /* Else operations to perform */
1037                 if (gb->async) {
1038                         if (type == GB_LOOPBACK_TYPE_PING)
1039                                 error = gb_loopback_async_ping(gb);
1040                         else if (type == GB_LOOPBACK_TYPE_TRANSFER)
1041                                 error = gb_loopback_async_transfer(gb, size);
1042                         else if (type == GB_LOOPBACK_TYPE_SINK)
1043                                 error = gb_loopback_async_sink(gb, size);
1044
1045                         if (error) {
1046                                 gb->error++;
1047                                 gb->iteration_count++;
1048                         }
1049                 } else {
1050                         /* We are effectively single threaded here */
1051                         if (type == GB_LOOPBACK_TYPE_PING)
1052                                 error = gb_loopback_sync_ping(gb);
1053                         else if (type == GB_LOOPBACK_TYPE_TRANSFER)
1054                                 error = gb_loopback_sync_transfer(gb, size);
1055                         else if (type == GB_LOOPBACK_TYPE_SINK)
1056                                 error = gb_loopback_sync_sink(gb, size);
1057
1058                         if (error)
1059                                 gb->error++;
1060                         gb->iteration_count++;
1061                         gb_loopback_calculate_stats(gb, !!error);
1062                 }
1063                 gb->send_count++;
1064
1065                 if (us_wait) {
1066                         if (us_wait < 20000)
1067                                 usleep_range(us_wait, us_wait + 100);
1068                         else
1069                                 msleep(us_wait / 1000);
1070                 }
1071         }
1072
1073         gb_pm_runtime_put_autosuspend(bundle);
1074
1075         return 0;
1076 }
1077
1078 static int gb_loopback_dbgfs_latency_show_common(struct seq_file *s,
1079                                                  struct kfifo *kfifo,
1080                                                  struct mutex *mutex)
1081 {
1082         u32 latency;
1083         int retval;
1084
1085         if (kfifo_len(kfifo) == 0) {
1086                 retval = -EAGAIN;
1087                 goto done;
1088         }
1089
1090         mutex_lock(mutex);
1091         retval = kfifo_out(kfifo, &latency, sizeof(latency));
1092         if (retval > 0) {
1093                 seq_printf(s, "%u", latency);
1094                 retval = 0;
1095         }
1096         mutex_unlock(mutex);
1097 done:
1098         return retval;
1099 }
1100
1101 static int gb_loopback_dbgfs_latency_show(struct seq_file *s, void *unused)
1102 {
1103         struct gb_loopback *gb = s->private;
1104
1105         return gb_loopback_dbgfs_latency_show_common(s, &gb->kfifo_lat,
1106                                                      &gb->mutex);
1107 }
1108
1109 static int gb_loopback_latency_open(struct inode *inode, struct file *file)
1110 {
1111         return single_open(file, gb_loopback_dbgfs_latency_show,
1112                            inode->i_private);
1113 }
1114
1115 static const struct file_operations gb_loopback_debugfs_latency_ops = {
1116         .open           = gb_loopback_latency_open,
1117         .read           = seq_read,
1118         .llseek         = seq_lseek,
1119         .release        = single_release,
1120 };
1121
1122 static int gb_loopback_bus_id_compare(void *priv, struct list_head *lha,
1123                                       struct list_head *lhb)
1124 {
1125         struct gb_loopback *a = list_entry(lha, struct gb_loopback, entry);
1126         struct gb_loopback *b = list_entry(lhb, struct gb_loopback, entry);
1127         struct gb_connection *ca = a->connection;
1128         struct gb_connection *cb = b->connection;
1129
1130         if (ca->bundle->intf->interface_id < cb->bundle->intf->interface_id)
1131                 return -1;
1132         if (cb->bundle->intf->interface_id < ca->bundle->intf->interface_id)
1133                 return 1;
1134         if (ca->bundle->id < cb->bundle->id)
1135                 return -1;
1136         if (cb->bundle->id < ca->bundle->id)
1137                 return 1;
1138         if (ca->intf_cport_id < cb->intf_cport_id)
1139                 return -1;
1140         else if (cb->intf_cport_id < ca->intf_cport_id)
1141                 return 1;
1142
1143         return 0;
1144 }
1145
1146 static void gb_loopback_insert_id(struct gb_loopback *gb)
1147 {
1148         struct gb_loopback *gb_list;
1149         u32 new_lbid = 0;
1150
1151         /* perform an insertion sort */
1152         list_add_tail(&gb->entry, &gb_dev.list);
1153         list_sort(NULL, &gb_dev.list, gb_loopback_bus_id_compare);
1154         list_for_each_entry(gb_list, &gb_dev.list, entry) {
1155                 gb_list->lbid = 1 << new_lbid;
1156                 new_lbid++;
1157         }
1158 }
1159
1160 #define DEBUGFS_NAMELEN 32
1161
1162 static int gb_loopback_probe(struct gb_bundle *bundle,
1163                              const struct greybus_bundle_id *id)
1164 {
1165         struct greybus_descriptor_cport *cport_desc;
1166         struct gb_connection *connection;
1167         struct gb_loopback *gb;
1168         struct device *dev;
1169         int retval;
1170         char name[DEBUGFS_NAMELEN];
1171         unsigned long flags;
1172
1173         if (bundle->num_cports != 1)
1174                 return -ENODEV;
1175
1176         cport_desc = &bundle->cport_desc[0];
1177         if (cport_desc->protocol_id != GREYBUS_PROTOCOL_LOOPBACK)
1178                 return -ENODEV;
1179
1180         gb = kzalloc(sizeof(*gb), GFP_KERNEL);
1181         if (!gb)
1182                 return -ENOMEM;
1183
1184         connection = gb_connection_create(bundle, le16_to_cpu(cport_desc->id),
1185                                           gb_loopback_request_handler);
1186         if (IS_ERR(connection)) {
1187                 retval = PTR_ERR(connection);
1188                 goto out_kzalloc;
1189         }
1190
1191         gb->connection = connection;
1192         greybus_set_drvdata(bundle, gb);
1193
1194         init_waitqueue_head(&gb->wq);
1195         init_waitqueue_head(&gb->wq_completion);
1196         atomic_set(&gb->outstanding_operations, 0);
1197         gb_loopback_reset_stats(gb);
1198
1199         /* Reported values to user-space for min/max timeouts */
1200         gb->timeout_min = jiffies_to_usecs(GB_LOOPBACK_TIMEOUT_MIN);
1201         gb->timeout_max = jiffies_to_usecs(GB_LOOPBACK_TIMEOUT_MAX);
1202
1203         if (!gb_dev.count) {
1204                 /* Calculate maximum payload */
1205                 gb_dev.size_max = gb_operation_get_payload_size_max(connection);
1206                 if (gb_dev.size_max <=
1207                         sizeof(struct gb_loopback_transfer_request)) {
1208                         retval = -EINVAL;
1209                         goto out_connection_destroy;
1210                 }
1211                 gb_dev.size_max -= sizeof(struct gb_loopback_transfer_request);
1212         }
1213
1214         /* Create per-connection sysfs and debugfs data-points */
1215         snprintf(name, sizeof(name), "raw_latency_%s",
1216                  dev_name(&connection->bundle->dev));
1217         gb->file = debugfs_create_file(name, S_IFREG | 0444, gb_dev.root, gb,
1218                                        &gb_loopback_debugfs_latency_ops);
1219
1220         gb->id = ida_simple_get(&loopback_ida, 0, 0, GFP_KERNEL);
1221         if (gb->id < 0) {
1222                 retval = gb->id;
1223                 goto out_debugfs_remove;
1224         }
1225
1226         retval = gb_connection_enable(connection);
1227         if (retval)
1228                 goto out_ida_remove;
1229
1230         dev = device_create_with_groups(&loopback_class,
1231                                         &connection->bundle->dev,
1232                                         MKDEV(0, 0), gb, loopback_groups,
1233                                         "gb_loopback%d", gb->id);
1234         if (IS_ERR(dev)) {
1235                 retval = PTR_ERR(dev);
1236                 goto out_connection_disable;
1237         }
1238         gb->dev = dev;
1239
1240         /* Allocate kfifo */
1241         if (kfifo_alloc(&gb->kfifo_lat, kfifo_depth * sizeof(u32),
1242                           GFP_KERNEL)) {
1243                 retval = -ENOMEM;
1244                 goto out_conn;
1245         }
1246         if (kfifo_alloc(&gb->kfifo_ts, kfifo_depth * sizeof(struct timeval) * 2,
1247                           GFP_KERNEL)) {
1248                 retval = -ENOMEM;
1249                 goto out_kfifo0;
1250         }
1251
1252         /* Fork worker thread */
1253         mutex_init(&gb->mutex);
1254         gb->task = kthread_run(gb_loopback_fn, gb, "gb_loopback");
1255         if (IS_ERR(gb->task)) {
1256                 retval = PTR_ERR(gb->task);
1257                 goto out_kfifo1;
1258         }
1259
1260         spin_lock_irqsave(&gb_dev.lock, flags);
1261         gb_loopback_insert_id(gb);
1262         gb_dev.count++;
1263         spin_unlock_irqrestore(&gb_dev.lock, flags);
1264
1265         gb_connection_latency_tag_enable(connection);
1266
1267         gb_pm_runtime_put_autosuspend(bundle);
1268
1269         return 0;
1270
1271 out_kfifo1:
1272         kfifo_free(&gb->kfifo_ts);
1273 out_kfifo0:
1274         kfifo_free(&gb->kfifo_lat);
1275 out_conn:
1276         device_unregister(dev);
1277 out_connection_disable:
1278         gb_connection_disable(connection);
1279 out_ida_remove:
1280         ida_simple_remove(&loopback_ida, gb->id);
1281 out_debugfs_remove:
1282         debugfs_remove(gb->file);
1283 out_connection_destroy:
1284         gb_connection_destroy(connection);
1285 out_kzalloc:
1286         kfree(gb);
1287
1288         return retval;
1289 }
1290
1291 static void gb_loopback_disconnect(struct gb_bundle *bundle)
1292 {
1293         struct gb_loopback *gb = greybus_get_drvdata(bundle);
1294         unsigned long flags;
1295         int ret;
1296
1297         ret = gb_pm_runtime_get_sync(bundle);
1298         if (ret)
1299                 gb_pm_runtime_get_noresume(bundle);
1300
1301         gb_connection_disable(gb->connection);
1302
1303         if (!IS_ERR_OR_NULL(gb->task))
1304                 kthread_stop(gb->task);
1305
1306         kfifo_free(&gb->kfifo_lat);
1307         kfifo_free(&gb->kfifo_ts);
1308         gb_connection_latency_tag_disable(gb->connection);
1309         debugfs_remove(gb->file);
1310
1311         /*
1312          * FIXME: gb_loopback_async_wait_all() is redundant now, as connection
1313          * is disabled at the beginning and so we can't have any more
1314          * incoming/outgoing requests.
1315          */
1316         gb_loopback_async_wait_all(gb);
1317
1318         spin_lock_irqsave(&gb_dev.lock, flags);
1319         gb_dev.count--;
1320         list_del(&gb->entry);
1321         spin_unlock_irqrestore(&gb_dev.lock, flags);
1322
1323         device_unregister(gb->dev);
1324         ida_simple_remove(&loopback_ida, gb->id);
1325
1326         gb_connection_destroy(gb->connection);
1327         kfree(gb);
1328 }
1329
1330 static const struct greybus_bundle_id gb_loopback_id_table[] = {
1331         { GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_LOOPBACK) },
1332         { }
1333 };
1334 MODULE_DEVICE_TABLE(greybus, gb_loopback_id_table);
1335
1336 static struct greybus_driver gb_loopback_driver = {
1337         .name           = "loopback",
1338         .probe          = gb_loopback_probe,
1339         .disconnect     = gb_loopback_disconnect,
1340         .id_table       = gb_loopback_id_table,
1341 };
1342
1343 static int loopback_init(void)
1344 {
1345         int retval;
1346
1347         INIT_LIST_HEAD(&gb_dev.list);
1348         INIT_LIST_HEAD(&gb_dev.list_op_async);
1349         spin_lock_init(&gb_dev.lock);
1350         gb_dev.root = debugfs_create_dir("gb_loopback", NULL);
1351
1352         retval = class_register(&loopback_class);
1353         if (retval)
1354                 goto err;
1355
1356         retval = greybus_register(&gb_loopback_driver);
1357         if (retval)
1358                 goto err_unregister;
1359
1360         return 0;
1361
1362 err_unregister:
1363         class_unregister(&loopback_class);
1364 err:
1365         debugfs_remove_recursive(gb_dev.root);
1366         return retval;
1367 }
1368 module_init(loopback_init);
1369
1370 static void __exit loopback_exit(void)
1371 {
1372         debugfs_remove_recursive(gb_dev.root);
1373         greybus_deregister(&gb_loopback_driver);
1374         class_unregister(&loopback_class);
1375         ida_destroy(&loopback_ida);
1376 }
1377 module_exit(loopback_exit);
1378
1379 MODULE_LICENSE("GPL v2");