drivers/staging/most/mostcore/core.c

   1 /*
   2  * core.c - Implementation of core module of MOST Linux driver stack
   3  *
   4  * Copyright (C) 2013-2015 Microchip Technology Germany II GmbH & Co. KG
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * This file is licensed under GPLv2.
  12  */
  13
  14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  15 #include <linux/module.h>
  16 #include <linux/fs.h>
  17 #include <linux/slab.h>
  18 #include <linux/init.h>
  19 #include <linux/device.h>
  20 #include <linux/list.h>
  21 #include <linux/poll.h>
  22 #include <linux/wait.h>
  23 #include <linux/kobject.h>
  24 #include <linux/mutex.h>
  25 #include <linux/completion.h>
  26 #include <linux/sysfs.h>
  27 #include <linux/kthread.h>
  28 #include <linux/dma-mapping.h>
  29 #include <linux/idr.h>
  30 #include "mostcore.h"
  31
  32 #define MAX_CHANNELS    64
  33 #define STRING_SIZE     80
  34
  35 static struct class *most_class;
  36 static struct device *class_glue_dir;
  37 static struct ida mdev_id;
  38 static int modref;
  39
  40 struct most_c_obj {
  41         struct kobject kobj;
  42         struct completion cleanup;
  43         atomic_t mbo_ref;
  44         atomic_t mbo_nq_level;
  45         uint16_t channel_id;
  46         bool is_poisoned;
  47         bool is_started;
  48         int is_starving;
  49         struct most_interface *iface;
  50         struct most_inst_obj *inst;
  51         struct most_channel_config cfg;
  52         bool keep_mbo;
  53         bool enqueue_halt;
  54         struct list_head fifo;
  55         spinlock_t fifo_lock;
  56         struct list_head halt_fifo;
  57         struct list_head list;
  58         struct most_aim *first_aim;
  59         struct most_aim *second_aim;
  60         struct list_head trash_fifo;
  61         struct task_struct *hdm_enqueue_task;
  62         struct mutex stop_task_mutex;
  63         wait_queue_head_t hdm_fifo_wq;
  64 };
  65 #define to_c_obj(d) container_of(d, struct most_c_obj, kobj)
  66
  67 struct most_inst_obj {
  68         int dev_id;
  69         atomic_t tainted;
  70         struct most_interface *iface;
  71         struct list_head channel_list;
  72         struct most_c_obj *channel[MAX_CHANNELS];
  73         struct kobject kobj;
  74         struct list_head list;
  75 };
  76 #define to_inst_obj(d) container_of(d, struct most_inst_obj, kobj)
  77
  78 /**
  79  * list_pop_mbo - retrieves the first MBO of the list and removes it
  80  * @ptr: the list head to grab the MBO from.
  81  */
  82 #define list_pop_mbo(ptr)                                               \
  83 ({                                                                      \
  84         struct mbo *_mbo = list_first_entry(ptr, struct mbo, list);     \
  85         list_del(&_mbo->list);                                          \
  86         _mbo;                                                           \
  87 })
  88
  89 static struct mutex deregister_mutex;
  90
  91 /*                   ___             ___
  92  *                   ___C H A N N E L___
  93  */
  94
  95 /**
  96  * struct most_c_attr - to access the attributes of a channel object
  97  * @attr: attributes of a channel
  98  * @show: pointer to the show function
  99  * @store: pointer to the store function
 100  */
 101 struct most_c_attr {
 102         struct attribute attr;
 103         ssize_t (*show)(struct most_c_obj *d,
 104                         struct most_c_attr *attr,
 105                         char *buf);
 106         ssize_t (*store)(struct most_c_obj *d,
 107                          struct most_c_attr *attr,
 108                          const char *buf,
 109                          size_t count);
 110 };
 111 #define to_channel_attr(a) container_of(a, struct most_c_attr, attr)
 112
 113 #define MOST_CHNL_ATTR(_name, _mode, _show, _store) \
 114                 struct most_c_attr most_chnl_attr_##_name = \
 115                 __ATTR(_name, _mode, _show, _store)
 116
 117 /**
 118  * channel_attr_show - show function of channel object
 119  * @kobj: pointer to its kobject
 120  * @attr: pointer to its attributes
 121  * @buf: buffer
 122  */
 123 static ssize_t channel_attr_show(struct kobject *kobj, struct attribute *attr,
 124                                  char *buf)
 125 {
 126         struct most_c_attr *channel_attr = to_channel_attr(attr);
 127         struct most_c_obj *c_obj = to_c_obj(kobj);
 128
 129         if (!channel_attr->show)
 130                 return -EIO;
 131
 132         return channel_attr->show(c_obj, channel_attr, buf);
 133 }
 134
 135 /**
 136  * channel_attr_store - store function of channel object
 137  * @kobj: pointer to its kobject
 138  * @attr: pointer to its attributes
 139  * @buf: buffer
 140  * @len: length of buffer
 141  */
 142 static ssize_t channel_attr_store(struct kobject *kobj,
 143                                   struct attribute *attr,
 144                                   const char *buf,
 145                                   size_t len)
 146 {
 147         struct most_c_attr *channel_attr = to_channel_attr(attr);
 148         struct most_c_obj *c_obj = to_c_obj(kobj);
 149
 150         if (!channel_attr->store)
 151                 return -EIO;
 152         return channel_attr->store(c_obj, channel_attr, buf, len);
 153 }
 154
 155 static const struct sysfs_ops most_channel_sysfs_ops = {
 156         .show = channel_attr_show,
 157         .store = channel_attr_store,
 158 };
 159
 160 /**
 161  * most_free_mbo_coherent - free an MBO and its coherent buffer
 162  * @mbo: buffer to be released
 163  *
 164  */
 165 static void most_free_mbo_coherent(struct mbo *mbo)
 166 {
 167         struct most_c_obj *c = mbo->context;
 168         u16 const coherent_buf_size = c->cfg.buffer_size + c->cfg.extra_len;
 169
 170         dma_free_coherent(NULL, coherent_buf_size, mbo->virt_address,
 171                           mbo->bus_address);
 172         kfree(mbo);
 173         if (atomic_sub_and_test(1, &c->mbo_ref))
 174                 complete(&c->cleanup);
 175 }
 176
 177 /**
 178  * flush_channel_fifos - clear the channel fifos
 179  * @c: pointer to channel object
 180  */
 181 static void flush_channel_fifos(struct most_c_obj *c)
 182 {
 183         unsigned long flags, hf_flags;
 184         struct mbo *mbo, *tmp;
 185
 186         if (list_empty(&c->fifo) && list_empty(&c->halt_fifo))
 187                 return;
 188
 189         spin_lock_irqsave(&c->fifo_lock, flags);
 190         list_for_each_entry_safe(mbo, tmp, &c->fifo, list) {
 191                 list_del(&mbo->list);
 192                 spin_unlock_irqrestore(&c->fifo_lock, flags);
 193                 if (likely(mbo))
 194                         most_free_mbo_coherent(mbo);
 195                 spin_lock_irqsave(&c->fifo_lock, flags);
 196         }
 197         spin_unlock_irqrestore(&c->fifo_lock, flags);
 198
 199         spin_lock_irqsave(&c->fifo_lock, hf_flags);
 200         list_for_each_entry_safe(mbo, tmp, &c->halt_fifo, list) {
 201                 list_del(&mbo->list);
 202                 spin_unlock_irqrestore(&c->fifo_lock, hf_flags);
 203                 if (likely(mbo))
 204                         most_free_mbo_coherent(mbo);
 205                 spin_lock_irqsave(&c->fifo_lock, hf_flags);
 206         }
 207         spin_unlock_irqrestore(&c->fifo_lock, hf_flags);
 208
 209         if (unlikely((!list_empty(&c->fifo) || !list_empty(&c->halt_fifo))))
 210                 pr_info("WARN: fifo | trash fifo not empty\n");
 211 }
 212
 213 /**
 214  * flush_trash_fifo - clear the trash fifo
 215  * @c: pointer to channel object
 216  */
 217 static int flush_trash_fifo(struct most_c_obj *c)
 218 {
 219         struct mbo *mbo, *tmp;
 220         unsigned long flags;
 221
 222         spin_lock_irqsave(&c->fifo_lock, flags);
 223         list_for_each_entry_safe(mbo, tmp, &c->trash_fifo, list) {
 224                 list_del(&mbo->list);
 225                 spin_unlock_irqrestore(&c->fifo_lock, flags);
 226                 most_free_mbo_coherent(mbo);
 227                 spin_lock_irqsave(&c->fifo_lock, flags);
 228         }
 229         spin_unlock_irqrestore(&c->fifo_lock, flags);
 230         return 0;
 231 }
 232
 233 /**
 234  * most_channel_release - release function of channel object
 235  * @kobj: pointer to channel's kobject
 236  */
 237 static void most_channel_release(struct kobject *kobj)
 238 {
 239         struct most_c_obj *c = to_c_obj(kobj);
 240
 241         kfree(c);
 242 }
 243
 244 static ssize_t show_available_directions(struct most_c_obj *c,
 245                 struct most_c_attr *attr,
 246                 char *buf)
 247 {
 248         unsigned int i = c->channel_id;
 249
 250         strcpy(buf, "");
 251         if (c->iface->channel_vector[i].direction & MOST_CH_RX)
 252                 strcat(buf, "dir_rx ");
 253         if (c->iface->channel_vector[i].direction & MOST_CH_TX)
 254                 strcat(buf, "dir_tx ");
 255         strcat(buf, "\n");
 256         return strlen(buf) + 1;
 257 }
 258
 259 static ssize_t show_available_datatypes(struct most_c_obj *c,
 260                                         struct most_c_attr *attr,
 261                                         char *buf)
 262 {
 263         unsigned int i = c->channel_id;
 264
 265         strcpy(buf, "");
 266         if (c->iface->channel_vector[i].data_type & MOST_CH_CONTROL)
 267                 strcat(buf, "control ");
 268         if (c->iface->channel_vector[i].data_type & MOST_CH_ASYNC)
 269                 strcat(buf, "async ");
 270         if (c->iface->channel_vector[i].data_type & MOST_CH_SYNC)
 271                 strcat(buf, "sync ");
 272         if (c->iface->channel_vector[i].data_type & MOST_CH_ISOC_AVP)
 273                 strcat(buf, "isoc_avp ");
 274         strcat(buf, "\n");
 275         return strlen(buf) + 1;
 276 }
 277
 278 static
 279 ssize_t show_number_of_packet_buffers(struct most_c_obj *c,
 280                                       struct most_c_attr *attr,
 281                                       char *buf)
 282 {
 283         unsigned int i = c->channel_id;
 284
 285         return snprintf(buf, PAGE_SIZE, "%d\n",
 286                         c->iface->channel_vector[i].num_buffers_packet);
 287 }
 288
 289 static
 290 ssize_t show_number_of_stream_buffers(struct most_c_obj *c,
 291                                       struct most_c_attr *attr,
 292                                       char *buf)
 293 {
 294         unsigned int i = c->channel_id;
 295
 296         return snprintf(buf, PAGE_SIZE, "%d\n",
 297                         c->iface->channel_vector[i].num_buffers_streaming);
 298 }
 299
 300 static
 301 ssize_t show_size_of_packet_buffer(struct most_c_obj *c,
 302                                    struct most_c_attr *attr,
 303                                    char *buf)
 304 {
 305         unsigned int i = c->channel_id;
 306
 307         return snprintf(buf, PAGE_SIZE, "%d\n",
 308                         c->iface->channel_vector[i].buffer_size_packet);
 309 }
 310
 311 static
 312 ssize_t show_size_of_stream_buffer(struct most_c_obj *c,
 313                                    struct most_c_attr *attr,
 314                                    char *buf)
 315 {
 316         unsigned int i = c->channel_id;
 317
 318         return snprintf(buf, PAGE_SIZE, "%d\n",
 319                         c->iface->channel_vector[i].buffer_size_streaming);
 320 }
 321
 322 static ssize_t show_channel_starving(struct most_c_obj *c,
 323                                      struct most_c_attr *attr,
 324                                      char *buf)
 325 {
 326         return snprintf(buf, PAGE_SIZE, "%d\n", c->is_starving);
 327 }
 328
 329
 330 #define create_show_channel_attribute(val) \
 331         static MOST_CHNL_ATTR(val, S_IRUGO, show_##val, NULL)
 332
 333 create_show_channel_attribute(available_directions);
 334 create_show_channel_attribute(available_datatypes);
 335 create_show_channel_attribute(number_of_packet_buffers);
 336 create_show_channel_attribute(number_of_stream_buffers);
 337 create_show_channel_attribute(size_of_stream_buffer);
 338 create_show_channel_attribute(size_of_packet_buffer);
 339 create_show_channel_attribute(channel_starving);
 340
 341 static ssize_t show_set_number_of_buffers(struct most_c_obj *c,
 342                                           struct most_c_attr *attr,
 343                                           char *buf)
 344 {
 345         return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.num_buffers);
 346 }
 347
 348 static ssize_t store_set_number_of_buffers(struct most_c_obj *c,
 349                                            struct most_c_attr *attr,
 350                                            const char *buf,
 351                                            size_t count)
 352 {
 353         int ret = kstrtou16(buf, 0, &c->cfg.num_buffers);
 354
 355         if (ret)
 356                 return ret;
 357         return count;
 358 }
 359
 360 static ssize_t show_set_buffer_size(struct most_c_obj *c,
 361                                     struct most_c_attr *attr,
 362                                     char *buf)
 363 {
 364         return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.buffer_size);
 365 }
 366
 367 static ssize_t store_set_buffer_size(struct most_c_obj *c,
 368                                      struct most_c_attr *attr,
 369                                      const char *buf,
 370                                      size_t count)
 371 {
 372         int ret = kstrtou16(buf, 0, &c->cfg.buffer_size);
 373
 374         if (ret)
 375                 return ret;
 376         return count;
 377 }
 378
 379 static ssize_t show_set_direction(struct most_c_obj *c,
 380                                   struct most_c_attr *attr,
 381                                   char *buf)
 382 {
 383         if (c->cfg.direction & MOST_CH_TX)
 384                 return snprintf(buf, PAGE_SIZE, "dir_tx\n");
 385         else if (c->cfg.direction & MOST_CH_RX)
 386                 return snprintf(buf, PAGE_SIZE, "dir_rx\n");
 387         return snprintf(buf, PAGE_SIZE, "unconfigured\n");
 388 }
 389
 390 static ssize_t store_set_direction(struct most_c_obj *c,
 391                                    struct most_c_attr *attr,
 392                                    const char *buf,
 393                                    size_t count)
 394 {
 395         if (!strcmp(buf, "dir_rx\n"))
 396                 c->cfg.direction = MOST_CH_RX;
 397         else if (!strcmp(buf, "dir_tx\n"))
 398                 c->cfg.direction = MOST_CH_TX;
 399         else {
 400                 pr_info("WARN: invalid attribute settings\n");
 401                 return -EINVAL;
 402         }
 403         return count;
 404 }
 405
 406 static ssize_t show_set_datatype(struct most_c_obj *c,
 407                                  struct most_c_attr *attr,
 408                                  char *buf)
 409 {
 410         if (c->cfg.data_type & MOST_CH_CONTROL)
 411                 return snprintf(buf, PAGE_SIZE, "control\n");
 412         else if (c->cfg.data_type & MOST_CH_ASYNC)
 413                 return snprintf(buf, PAGE_SIZE, "async\n");
 414         else if (c->cfg.data_type & MOST_CH_SYNC)
 415                 return snprintf(buf, PAGE_SIZE, "sync\n");
 416         else if (c->cfg.data_type & MOST_CH_ISOC_AVP)
 417                 return snprintf(buf, PAGE_SIZE, "isoc_avp\n");
 418         return snprintf(buf, PAGE_SIZE, "unconfigured\n");
 419 }
 420
 421 static ssize_t store_set_datatype(struct most_c_obj *c,
 422                                   struct most_c_attr *attr,
 423                                   const char *buf,
 424                                   size_t count)
 425 {
 426         if (!strcmp(buf, "control\n"))
 427                 c->cfg.data_type = MOST_CH_CONTROL;
 428         else if (!strcmp(buf, "async\n"))
 429                 c->cfg.data_type = MOST_CH_ASYNC;
 430         else if (!strcmp(buf, "sync\n"))
 431                 c->cfg.data_type = MOST_CH_SYNC;
 432         else if (!strcmp(buf, "isoc_avp\n"))
 433                 c->cfg.data_type = MOST_CH_ISOC_AVP;
 434         else {
 435                 pr_info("WARN: invalid attribute settings\n");
 436                 return -EINVAL;
 437         }
 438         return count;
 439 }
 440
 441 static ssize_t show_set_subbuffer_size(struct most_c_obj *c,
 442                                        struct most_c_attr *attr,
 443                                        char *buf)
 444 {
 445         return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.subbuffer_size);
 446 }
 447
 448 static ssize_t store_set_subbuffer_size(struct most_c_obj *c,
 449                                         struct most_c_attr *attr,
 450                                         const char *buf,
 451                                         size_t count)
 452 {
 453         int ret = kstrtou16(buf, 0, &c->cfg.subbuffer_size);
 454
 455         if (ret)
 456                 return ret;
 457         return count;
 458 }
 459
 460 static ssize_t show_set_packets_per_xact(struct most_c_obj *c,
 461                                          struct most_c_attr *attr,
 462                                          char *buf)
 463 {
 464         return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.packets_per_xact);
 465 }
 466
 467 static ssize_t store_set_packets_per_xact(struct most_c_obj *c,
 468                                           struct most_c_attr *attr,
 469                                           const char *buf,
 470                                           size_t count)
 471 {
 472         int ret = kstrtou16(buf, 0, &c->cfg.packets_per_xact);
 473
 474         if (ret)
 475                 return ret;
 476         return count;
 477 }
 478
 479 #define create_channel_attribute(value) \
 480         static MOST_CHNL_ATTR(value, S_IRUGO | S_IWUSR, \
 481                               show_##value, \
 482                               store_##value)
 483
 484 create_channel_attribute(set_buffer_size);
 485 create_channel_attribute(set_number_of_buffers);
 486 create_channel_attribute(set_direction);
 487 create_channel_attribute(set_datatype);
 488 create_channel_attribute(set_subbuffer_size);
 489 create_channel_attribute(set_packets_per_xact);
 490
 491
 492 /**
 493  * most_channel_def_attrs - array of default attributes of channel object
 494  */
 495 static struct attribute *most_channel_def_attrs[] = {
 496         &most_chnl_attr_available_directions.attr,
 497         &most_chnl_attr_available_datatypes.attr,
 498         &most_chnl_attr_number_of_packet_buffers.attr,
 499         &most_chnl_attr_number_of_stream_buffers.attr,
 500         &most_chnl_attr_size_of_packet_buffer.attr,
 501         &most_chnl_attr_size_of_stream_buffer.attr,
 502         &most_chnl_attr_set_number_of_buffers.attr,
 503         &most_chnl_attr_set_buffer_size.attr,
 504         &most_chnl_attr_set_direction.attr,
 505         &most_chnl_attr_set_datatype.attr,
 506         &most_chnl_attr_set_subbuffer_size.attr,
 507         &most_chnl_attr_set_packets_per_xact.attr,
 508         &most_chnl_attr_channel_starving.attr,
 509         NULL,
 510 };
 511
 512 static struct kobj_type most_channel_ktype = {
 513         .sysfs_ops = &most_channel_sysfs_ops,
 514         .release = most_channel_release,
 515         .default_attrs = most_channel_def_attrs,
 516 };
 517
 518 static struct kset *most_channel_kset;
 519
 520 /**
 521  * create_most_c_obj - allocates a channel object
 522  * @name: name of the channel object
 523  * @parent: parent kobject
 524  *
 525  * This create a channel object and registers it with sysfs.
 526  * Returns a pointer to the object or NULL when something went wrong.
 527  */
 528 static struct most_c_obj *
 529 create_most_c_obj(const char *name, struct kobject *parent)
 530 {
 531         struct most_c_obj *c;
 532         int retval;
 533
 534         c = kzalloc(sizeof(*c), GFP_KERNEL);
 535         if (!c)
 536                 return NULL;
 537         c->kobj.kset = most_channel_kset;
 538         retval = kobject_init_and_add(&c->kobj, &most_channel_ktype, parent,
 539                                       "%s", name);
 540         if (retval) {
 541                 kobject_put(&c->kobj);
 542                 return NULL;
 543         }
 544         kobject_uevent(&c->kobj, KOBJ_ADD);
 545         return c;
 546 }
 547
 548 /**
 549  * destroy_most_c_obj - channel release function
 550  * @c: pointer to channel object
 551  *
 552  * This decrements the reference counter of the channel object.
 553  * If the reference count turns zero, its release function is called.
 554  */
 555 static void destroy_most_c_obj(struct most_c_obj *c)
 556 {
 557         if (c->first_aim)
 558                 c->first_aim->disconnect_channel(c->iface, c->channel_id);
 559         if (c->second_aim)
 560                 c->second_aim->disconnect_channel(c->iface, c->channel_id);
 561         c->first_aim = NULL;
 562         c->second_aim = NULL;
 563
 564         mutex_lock(&deregister_mutex);
 565         flush_trash_fifo(c);
 566         flush_channel_fifos(c);
 567         mutex_unlock(&deregister_mutex);
 568         kobject_put(&c->kobj);
 569 }
 570
 571 /*                   ___               ___
 572  *                   ___I N S T A N C E___
 573  */
 574 #define MOST_INST_ATTR(_name, _mode, _show, _store) \
 575                 struct most_inst_attribute most_inst_attr_##_name = \
 576                 __ATTR(_name, _mode, _show, _store)
 577
 578 static struct list_head instance_list;
 579
 580 /**
 581  * struct most_inst_attribute - to access the attributes of instance object
 582  * @attr: attributes of an instance
 583  * @show: pointer to the show function
 584  * @store: pointer to the store function
 585  */
 586 struct most_inst_attribute {
 587         struct attribute attr;
 588         ssize_t (*show)(struct most_inst_obj *d,
 589                         struct most_inst_attribute *attr,
 590                         char *buf);
 591         ssize_t (*store)(struct most_inst_obj *d,
 592                          struct most_inst_attribute *attr,
 593                          const char *buf,
 594                          size_t count);
 595 };
 596 #define to_instance_attr(a) \
 597         container_of(a, struct most_inst_attribute, attr)
 598
 599 /**
 600  * instance_attr_show - show function for an instance object
 601  * @kobj: pointer to kobject
 602  * @attr: pointer to attribute struct
 603  * @buf: buffer
 604  */
 605 static ssize_t instance_attr_show(struct kobject *kobj,
 606                                   struct attribute *attr,
 607                                   char *buf)
 608 {
 609         struct most_inst_attribute *instance_attr;
 610         struct most_inst_obj *instance_obj;
 611
 612         instance_attr = to_instance_attr(attr);
 613         instance_obj = to_inst_obj(kobj);
 614
 615         if (!instance_attr->show)
 616                 return -EIO;
 617
 618         return instance_attr->show(instance_obj, instance_attr, buf);
 619 }
 620
 621 /**
 622  * instance_attr_store - store function for an instance object
 623  * @kobj: pointer to kobject
 624  * @attr: pointer to attribute struct
 625  * @buf: buffer
 626  * @len: length of buffer
 627  */
 628 static ssize_t instance_attr_store(struct kobject *kobj,
 629                                    struct attribute *attr,
 630                                    const char *buf,
 631                                    size_t len)
 632 {
 633         struct most_inst_attribute *instance_attr;
 634         struct most_inst_obj *instance_obj;
 635
 636         instance_attr = to_instance_attr(attr);
 637         instance_obj = to_inst_obj(kobj);
 638
 639         if (!instance_attr->store)
 640                 return -EIO;
 641
 642         return instance_attr->store(instance_obj, instance_attr, buf, len);
 643 }
 644
 645 static const struct sysfs_ops most_inst_sysfs_ops = {
 646         .show = instance_attr_show,
 647         .store = instance_attr_store,
 648 };
 649
 650 /**
 651  * most_inst_release - release function for instance object
 652  * @kobj: pointer to instance's kobject
 653  *
 654  * This frees the allocated memory for the instance object
 655  */
 656 static void most_inst_release(struct kobject *kobj)
 657 {
 658         struct most_inst_obj *inst = to_inst_obj(kobj);
 659
 660         kfree(inst);
 661 }
 662
 663 static ssize_t show_description(struct most_inst_obj *instance_obj,
 664                                 struct most_inst_attribute *attr,
 665                                 char *buf)
 666 {
 667         return snprintf(buf, PAGE_SIZE, "%s\n",
 668                         instance_obj->iface->description);
 669 }
 670
 671 static ssize_t show_interface(struct most_inst_obj *instance_obj,
 672                               struct most_inst_attribute *attr,
 673                               char *buf)
 674 {
 675         switch (instance_obj->iface->interface) {
 676         case ITYPE_LOOPBACK:
 677                 return snprintf(buf, PAGE_SIZE, "loopback\n");
 678         case ITYPE_I2C:
 679                 return snprintf(buf, PAGE_SIZE, "i2c\n");
 680         case ITYPE_I2S:
 681                 return snprintf(buf, PAGE_SIZE, "i2s\n");
 682         case ITYPE_TSI:
 683                 return snprintf(buf, PAGE_SIZE, "tsi\n");
 684         case ITYPE_HBI:
 685                 return snprintf(buf, PAGE_SIZE, "hbi\n");
 686         case ITYPE_MEDIALB_DIM:
 687                 return snprintf(buf, PAGE_SIZE, "mlb_dim\n");
 688         case ITYPE_MEDIALB_DIM2:
 689                 return snprintf(buf, PAGE_SIZE, "mlb_dim2\n");
 690         case ITYPE_USB:
 691                 return snprintf(buf, PAGE_SIZE, "usb\n");
 692         case ITYPE_PCIE:
 693                 return snprintf(buf, PAGE_SIZE, "pcie\n");
 694         }
 695         return snprintf(buf, PAGE_SIZE, "unknown\n");
 696 }
 697
 698 #define create_inst_attribute(value) \
 699         static MOST_INST_ATTR(value, S_IRUGO, show_##value, NULL)
 700
 701 create_inst_attribute(description);
 702 create_inst_attribute(interface);
 703
 704 static struct attribute *most_inst_def_attrs[] = {
 705         &most_inst_attr_description.attr,
 706         &most_inst_attr_interface.attr,
 707         NULL,
 708 };
 709
 710 static struct kobj_type most_inst_ktype = {
 711         .sysfs_ops = &most_inst_sysfs_ops,
 712         .release = most_inst_release,
 713         .default_attrs = most_inst_def_attrs,
 714 };
 715
 716 static struct kset *most_inst_kset;
 717
 718
 719 /**
 720  * create_most_inst_obj - creates an instance object
 721  * @name: name of the object to be created
 722  *
 723  * This allocates memory for an instance structure, assigns the proper kset
 724  * and registers it with sysfs.
 725  *
 726  * Returns a pointer to the instance object or NULL when something went wrong.
 727  */
 728 static struct most_inst_obj *create_most_inst_obj(const char *name)
 729 {
 730         struct most_inst_obj *inst;
 731         int retval;
 732
 733         inst = kzalloc(sizeof(*inst), GFP_KERNEL);
 734         if (!inst)
 735                 return NULL;
 736         inst->kobj.kset = most_inst_kset;
 737         retval = kobject_init_and_add(&inst->kobj, &most_inst_ktype, NULL,
 738                                       "%s", name);
 739         if (retval) {
 740                 kobject_put(&inst->kobj);
 741                 return NULL;
 742         }
 743         kobject_uevent(&inst->kobj, KOBJ_ADD);
 744         return inst;
 745 }
 746
 747 /**
 748  * destroy_most_inst_obj - MOST instance release function
 749  * @inst: pointer to the instance object
 750  *
 751  * This decrements the reference counter of the instance object.
 752  * If the reference count turns zero, its release function is called
 753  */
 754 static void destroy_most_inst_obj(struct most_inst_obj *inst)
 755 {
 756         struct most_c_obj *c, *tmp;
 757
 758         /* need to destroy channels first, since
 759          * each channel incremented the
 760          * reference count of the inst->kobj
 761          */
 762         list_for_each_entry_safe(c, tmp, &inst->channel_list, list) {
 763                 destroy_most_c_obj(c);
 764         }
 765         kobject_put(&inst->kobj);
 766 }
 767
 768 /*                   ___     ___
 769  *                   ___A I M___
 770  */
 771 struct most_aim_obj {
 772         struct kobject kobj;
 773         struct list_head list;
 774         struct most_aim *driver;
 775         char add_link[STRING_SIZE];
 776         char remove_link[STRING_SIZE];
 777 };
 778 #define to_aim_obj(d) container_of(d, struct most_aim_obj, kobj)
 779
 780 static struct list_head aim_list;
 781
 782
 783 /**
 784  * struct most_aim_attribute - to access the attributes of AIM object
 785  * @attr: attributes of an AIM
 786  * @show: pointer to the show function
 787  * @store: pointer to the store function
 788  */
 789 struct most_aim_attribute {
 790         struct attribute attr;
 791         ssize_t (*show)(struct most_aim_obj *d,
 792                         struct most_aim_attribute *attr,
 793                         char *buf);
 794         ssize_t (*store)(struct most_aim_obj *d,
 795                          struct most_aim_attribute *attr,
 796                          const char *buf,
 797                          size_t count);
 798 };
 799 #define to_aim_attr(a) container_of(a, struct most_aim_attribute, attr)
 800
 801 /**
 802  * aim_attr_show - show function of an AIM object
 803  * @kobj: pointer to kobject
 804  * @attr: pointer to attribute struct
 805  * @buf: buffer
 806  */
 807 static ssize_t aim_attr_show(struct kobject *kobj,
 808                              struct attribute *attr,
 809                              char *buf)
 810 {
 811         struct most_aim_attribute *aim_attr;
 812         struct most_aim_obj *aim_obj;
 813
 814         aim_attr = to_aim_attr(attr);
 815         aim_obj = to_aim_obj(kobj);
 816
 817         if (!aim_attr->show)
 818                 return -EIO;
 819
 820         return aim_attr->show(aim_obj, aim_attr, buf);
 821 }
 822
 823 /**
 824  * aim_attr_store - store function of an AIM object
 825  * @kobj: pointer to kobject
 826  * @attr: pointer to attribute struct
 827  * @buf: buffer
 828  * @len: length of buffer
 829  */
 830 static ssize_t aim_attr_store(struct kobject *kobj,
 831                               struct attribute *attr,
 832                               const char *buf,
 833                               size_t len)
 834 {
 835         struct most_aim_attribute *aim_attr;
 836         struct most_aim_obj *aim_obj;
 837
 838         aim_attr = to_aim_attr(attr);
 839         aim_obj = to_aim_obj(kobj);
 840
 841         if (!aim_attr->store)
 842                 return -EIO;
 843         return aim_attr->store(aim_obj, aim_attr, buf, len);
 844 }
 845
 846 static const struct sysfs_ops most_aim_sysfs_ops = {
 847         .show = aim_attr_show,
 848         .store = aim_attr_store,
 849 };
 850
 851 /**
 852  * most_aim_release - AIM release function
 853  * @kobj: pointer to AIM's kobject
 854  */
 855 static void most_aim_release(struct kobject *kobj)
 856 {
 857         struct most_aim_obj *aim_obj = to_aim_obj(kobj);
 858
 859         kfree(aim_obj);
 860 }
 861
 862 static ssize_t show_add_link(struct most_aim_obj *aim_obj,
 863                              struct most_aim_attribute *attr,
 864                              char *buf)
 865 {
 866         return snprintf(buf, PAGE_SIZE, "%s\n", aim_obj->add_link);
 867 }
 868
 869 /**
 870  * split_string - parses and changes string in the buffer buf and
 871  * splits it into two mandatory and one optional substrings.
 872  *
 873  * @buf: complete string from attribute 'add_channel'
 874  * @a: address of pointer to 1st substring (=instance name)
 875  * @b: address of pointer to 2nd substring (=channel name)
 876  * @c: optional address of pointer to 3rd substring (=user defined name)
 877  *
 878  * Examples:
 879  *
 880  * Input: "mdev0:ch0@ep_81:my_channel\n" or
 881  *        "mdev0:ch0@ep_81:my_channel"
 882  *
 883  * Output: *a -> "mdev0", *b -> "ch0@ep_81", *c -> "my_channel"
 884  *
 885  * Input: "mdev0:ch0@ep_81\n"
 886  * Output: *a -> "mdev0", *b -> "ch0@ep_81", *c -> ""
 887  *
 888  * Input: "mdev0:ch0@ep_81"
 889  * Output: *a -> "mdev0", *b -> "ch0@ep_81", *c == NULL
 890  */
 891 static int split_string(char *buf, char **a, char **b, char **c)
 892 {
 893         *a = strsep(&buf, ":");
 894         if (!*a)
 895                 return -EIO;
 896
 897         *b = strsep(&buf, ":\n");
 898         if (!*b)
 899                 return -EIO;
 900
 901         if (c)
 902                 *c = strsep(&buf, ":\n");
 903
 904         return 0;
 905 }
 906
 907 /**
 908  * get_channel_by_name - get pointer to channel object
 909  * @mdev: name of the device instance
 910  * @mdev_ch: name of the respective channel
 911  *
 912  * This retrieves the pointer to a channel object.
 913  */
 914 static struct
 915 most_c_obj *get_channel_by_name(char *mdev, char *mdev_ch)
 916 {
 917         struct most_c_obj *c, *tmp;
 918         struct most_inst_obj *i, *i_tmp;
 919         int found = 0;
 920
 921         list_for_each_entry_safe(i, i_tmp, &instance_list, list) {
 922                 if (!strcmp(kobject_name(&i->kobj), mdev)) {
 923                         found++;
 924                         break;
 925                 }
 926         }
 927         if (unlikely(!found))
 928                 return ERR_PTR(-EIO);
 929
 930         list_for_each_entry_safe(c, tmp, &i->channel_list, list) {
 931                 if (!strcmp(kobject_name(&c->kobj), mdev_ch)) {
 932                         found++;
 933                         break;
 934                 }
 935         }
 936         if (unlikely(2 > found))
 937                 return ERR_PTR(-EIO);
 938         return c;
 939 }
 940
 941 /**
 942  * store_add_link - store() function for add_link attribute
 943  * @aim_obj: pointer to AIM object
 944  * @attr: its attributes
 945  * @buf: buffer
 946  * @len: buffer length
 947  *
 948  * This parses the string given by buf and splits it into
 949  * three substrings. Note: third substring is optional. In case a cdev
 950  * AIM is loaded the optional 3rd substring will make up the name of
 951  * device node in the /dev directory. If omitted, the device node will
 952  * inherit the channel's name within sysfs.
 953  *
 954  * Searches for a pair of device and channel and probes the AIM
 955  *
 956  * Example:
 957  * (1) echo -n -e "mdev0:ch0@ep_81:my_rxchannel\n" >add_link
 958  * (2) echo -n -e "mdev0:ch0@ep_81\n" >add_link
 959  *
 960  * (1) would create the device node /dev/my_rxchannel
 961  * (2) would create the device node /dev/mdev0-ch0@ep_81
 962  */
 963 static ssize_t store_add_link(struct most_aim_obj *aim_obj,
 964                               struct most_aim_attribute *attr,
 965                               const char *buf,
 966                               size_t len)
 967 {
 968         struct most_c_obj *c;
 969         struct most_aim **aim_ptr;
 970         char buffer[STRING_SIZE];
 971         char *mdev;
 972         char *mdev_ch;
 973         char *mdev_devnod;
 974         char devnod_buf[STRING_SIZE];
 975         int ret;
 976         size_t max_len = min_t(size_t, len + 1, STRING_SIZE);
 977
 978         strlcpy(buffer, buf, max_len);
 979         strlcpy(aim_obj->add_link, buf, max_len);
 980
 981         ret = split_string(buffer, &mdev, &mdev_ch, &mdev_devnod);
 982         if (ret)
 983                 return ret;
 984
 985         if (!mdev_devnod || *mdev_devnod == 0) {
 986                 snprintf(devnod_buf, sizeof(devnod_buf), "%s-%s", mdev, mdev_ch);
 987                 mdev_devnod = devnod_buf;
 988         }
 989
 990         c = get_channel_by_name(mdev, mdev_ch);
 991         if (IS_ERR(c))
 992                 return -ENODEV;
 993
 994         if (!c->first_aim)
 995                 aim_ptr = &c->first_aim;
 996         else if (!c->second_aim)
 997                 aim_ptr = &c->second_aim;
 998         else
 999                 return -ENOSPC;
1000
1001         ret = aim_obj->driver->probe_channel(c->iface, c->channel_id,
1002                                              &c->cfg, &c->kobj, mdev_devnod);
1003         if (ret)
1004                 return ret;
1005         *aim_ptr = aim_obj->driver;
1006         return len;
1007 }
1008
1009 static struct most_aim_attribute most_aim_attr_add_link =
1010         __ATTR(add_link, S_IRUGO | S_IWUSR, show_add_link, store_add_link);
1011
1012 static ssize_t show_remove_link(struct most_aim_obj *aim_obj,
1013                                 struct most_aim_attribute *attr,
1014                                 char *buf)
1015 {
1016         return snprintf(buf, PAGE_SIZE, "%s\n", aim_obj->remove_link);
1017 }
1018
1019 /**
1020  * store_remove_link - store function for remove_link attribute
1021  * @aim_obj: pointer to AIM object
1022  * @attr: its attributes
1023  * @buf: buffer
1024  * @len: buffer length
1025  *
1026  * Example:
1027  * echo -n -e "mdev0:ch0@ep_81\n" >remove_link
1028  */
1029 static ssize_t store_remove_link(struct most_aim_obj *aim_obj,
1030                                  struct most_aim_attribute *attr,
1031                                  const char *buf,
1032                                  size_t len)
1033 {
1034         struct most_c_obj *c;
1035         char buffer[STRING_SIZE];
1036         char *mdev;
1037         char *mdev_ch;
1038         int ret;
1039         size_t max_len = min_t(size_t, len + 1, STRING_SIZE);
1040
1041         strlcpy(buffer, buf, max_len);
1042         strlcpy(aim_obj->remove_link, buf, max_len);
1043         ret = split_string(buffer, &mdev, &mdev_ch, NULL);
1044         if (ret)
1045                 return ret;
1046
1047         c = get_channel_by_name(mdev, mdev_ch);
1048         if (IS_ERR(c))
1049                 return -ENODEV;
1050
1051         if (c->first_aim == aim_obj->driver)
1052                 c->first_aim = NULL;
1053         if (c->second_aim == aim_obj->driver)
1054                 c->second_aim = NULL;
1055         if (aim_obj->driver->disconnect_channel(c->iface, c->channel_id))
1056                 return -EIO;
1057         return len;
1058 }
1059
1060 static struct most_aim_attribute most_aim_attr_remove_link =
1061         __ATTR(remove_link, S_IRUGO | S_IWUSR, show_remove_link, store_remove_link);
1062
1063 static struct attribute *most_aim_def_attrs[] = {
1064         &most_aim_attr_add_link.attr,
1065         &most_aim_attr_remove_link.attr,
1066         NULL,
1067 };
1068
1069 static struct kobj_type most_aim_ktype = {
1070         .sysfs_ops = &most_aim_sysfs_ops,
1071         .release = most_aim_release,
1072         .default_attrs = most_aim_def_attrs,
1073 };
1074
1075 static struct kset *most_aim_kset;
1076
1077 /**
1078  * create_most_aim_obj - creates an AIM object
1079  * @name: name of the AIM
1080  *
1081  * This creates an AIM object assigns the proper kset and registers
1082  * it with sysfs.
1083  * Returns a pointer to the object or NULL if something went wrong.
1084  */
1085 static struct most_aim_obj *create_most_aim_obj(const char *name)
1086 {
1087         struct most_aim_obj *most_aim;
1088         int retval;
1089
1090         most_aim = kzalloc(sizeof(*most_aim), GFP_KERNEL);
1091         if (!most_aim)
1092                 return NULL;
1093         most_aim->kobj.kset = most_aim_kset;
1094         retval = kobject_init_and_add(&most_aim->kobj, &most_aim_ktype,
1095                                       NULL, "%s", name);
1096         if (retval) {
1097                 kobject_put(&most_aim->kobj);
1098                 return NULL;
1099         }
1100         kobject_uevent(&most_aim->kobj, KOBJ_ADD);
1101         return most_aim;
1102 }
1103
1104 /**
1105  * destroy_most_aim_obj - AIM release function
1106  * @p: pointer to AIM object
1107  *
1108  * This decrements the reference counter of the AIM object. If the
1109  * reference count turns zero, its release function will be called.
1110  */
1111 static void destroy_most_aim_obj(struct most_aim_obj *p)
1112 {
1113         kobject_put(&p->kobj);
1114 }
1115
1116
1117 /*                   ___       ___
1118  *                   ___C O R E___
1119  */
1120
1121 /**
1122  * Instantiation of the MOST bus
1123  */
1124 static struct bus_type most_bus = {
1125         .name = "most",
1126 };
1127
1128 /**
1129  * Instantiation of the core driver
1130  */
1131 static struct device_driver mostcore = {
1132         .name = "mostcore",
1133         .bus = &most_bus,
1134 };
1135
1136 static inline void trash_mbo(struct mbo *mbo)
1137 {
1138         unsigned long flags;
1139         struct most_c_obj *c = mbo->context;
1140
1141         spin_lock_irqsave(&c->fifo_lock, flags);
1142         list_add(&mbo->list, &c->trash_fifo);
1143         spin_unlock_irqrestore(&c->fifo_lock, flags);
1144 }
1145
1146 static struct mbo *get_hdm_mbo(struct most_c_obj *c)
1147 {
1148         unsigned long flags;
1149         struct mbo *mbo;
1150
1151         spin_lock_irqsave(&c->fifo_lock, flags);
1152         if (c->enqueue_halt || list_empty(&c->halt_fifo))
1153                 mbo = NULL;
1154         else
1155                 mbo = list_pop_mbo(&c->halt_fifo);
1156         spin_unlock_irqrestore(&c->fifo_lock, flags);
1157         return mbo;
1158 }
1159
1160 static void nq_hdm_mbo(struct mbo *mbo)
1161 {
1162         unsigned long flags;
1163         struct most_c_obj *c = mbo->context;
1164
1165         spin_lock_irqsave(&c->fifo_lock, flags);
1166         list_add_tail(&mbo->list, &c->halt_fifo);
1167         spin_unlock_irqrestore(&c->fifo_lock, flags);
1168         wake_up_interruptible(&c->hdm_fifo_wq);
1169 }
1170
1171 static int hdm_enqueue_thread(void *data)
1172 {
1173         struct most_c_obj *c = data;
1174         struct mbo *mbo;
1175         typeof(c->iface->enqueue) enqueue = c->iface->enqueue;
1176
1177         while (likely(!kthread_should_stop())) {
1178                 wait_event_interruptible(c->hdm_fifo_wq,
1179                                          (mbo = get_hdm_mbo(c))
1180                                          || kthread_should_stop());
1181
1182                 if (unlikely(!mbo))
1183                         continue;
1184
1185                 if (c->cfg.direction == MOST_CH_RX)
1186                         mbo->buffer_length = c->cfg.buffer_size;
1187
1188                 if (unlikely(enqueue(mbo->ifp, mbo->hdm_channel_id, mbo))) {
1189                         pr_err("hdm enqueue failed\n");
1190                         nq_hdm_mbo(mbo);
1191                         c->hdm_enqueue_task = NULL;
1192                         return 0;
1193                 }
1194         }
1195
1196         return 0;
1197 }
1198
1199 static int run_enqueue_thread(struct most_c_obj *c, int channel_id)
1200 {
1201         struct task_struct *task =
1202                 kthread_run(&hdm_enqueue_thread, c, "hdm_fifo_%d", channel_id);
1203
1204         if (IS_ERR(task))
1205                 return PTR_ERR(task);
1206
1207         c->hdm_enqueue_task = task;
1208         return 0;
1209 }
1210
1211 /**
1212  * arm_mbo - recycle MBO for further usage
1213  * @mbo: buffer object
1214  *
1215  * This puts an MBO back to the list to have it ready for up coming
1216  * tx transactions.
1217  *
1218  * In case the MBO belongs to a channel that recently has been
1219  * poisoned, the MBO is scheduled to be trashed.
1220  * Calls the completion handler of an attached AIM.
1221  */
1222 static void arm_mbo(struct mbo *mbo)
1223 {
1224         unsigned long flags;
1225         struct most_c_obj *c;
1226
1227         BUG_ON((!mbo) || (!mbo->context));
1228         c = mbo->context;
1229
1230         if (c->is_poisoned) {
1231                 trash_mbo(mbo);
1232                 return;
1233         }
1234
1235         spin_lock_irqsave(&c->fifo_lock, flags);
1236         list_add_tail(&mbo->list, &c->fifo);
1237         spin_unlock_irqrestore(&c->fifo_lock, flags);
1238
1239         if (c->second_aim && c->second_aim->tx_completion)
1240                 c->second_aim->tx_completion(c->iface, c->channel_id);
1241         if (c->first_aim && c->first_aim->tx_completion)
1242                 c->first_aim->tx_completion(c->iface, c->channel_id);
1243 }
1244
1245 /**
1246  * arm_mbo_chain - helper function that arms an MBO chain for the HDM
1247  * @c: pointer to interface channel
1248  * @dir: direction of the channel
1249  * @compl: pointer to completion function
1250  *
1251  * This allocates buffer objects including the containing DMA coherent
1252  * buffer and puts them in the fifo.
1253  * Buffers of Rx channels are put in the kthread fifo, hence immediately
1254  * submitted to the HDM.
1255  *
1256  * Returns the number of allocated and enqueued MBOs.
1257  */
1258 static int arm_mbo_chain(struct most_c_obj *c, int dir,
1259                          void (*compl)(struct mbo *))
1260 {
1261         unsigned int i;
1262         int retval;
1263         struct mbo *mbo;
1264         u32 coherent_buf_size = c->cfg.buffer_size + c->cfg.extra_len;
1265
1266         atomic_set(&c->mbo_nq_level, 0);
1267
1268         for (i = 0; i < c->cfg.num_buffers; i++) {
1269                 mbo = kzalloc(sizeof(*mbo), GFP_KERNEL);
1270                 if (!mbo) {
1271                         pr_info("WARN: Allocation of MBO failed.\n");
1272                         retval = i;
1273                         goto _exit;
1274                 }
1275                 mbo->context = c;
1276                 mbo->ifp = c->iface;
1277                 mbo->hdm_channel_id = c->channel_id;
1278                 mbo->virt_address = dma_alloc_coherent(NULL,
1279                                                        coherent_buf_size,
1280                                                        &mbo->bus_address,
1281                                                        GFP_KERNEL);
1282                 if (!mbo->virt_address) {
1283                         pr_info("WARN: No DMA coherent buffer.\n");
1284                         retval = i;
1285                         goto _error1;
1286                 }
1287                 mbo->complete = compl;
1288                 if (dir == MOST_CH_RX) {
1289                         nq_hdm_mbo(mbo);
1290                         atomic_inc(&c->mbo_nq_level);
1291                 } else {
1292                         arm_mbo(mbo);
1293                 }
1294         }
1295         return i;
1296
1297 _error1:
1298         kfree(mbo);
1299 _exit:
1300         return retval;
1301 }
1302
1303 /**
1304  * most_submit_mbo - submits an MBO to fifo
1305  * @mbo: pointer to the MBO
1306  *
1307  */
1308 int most_submit_mbo(struct mbo *mbo)
1309 {
1310         struct most_c_obj *c;
1311         struct most_inst_obj *i;
1312
1313         if (unlikely((!mbo) || (!mbo->context))) {
1314                 pr_err("Bad MBO or missing channel reference\n");
1315                 return -EINVAL;
1316         }
1317         c = mbo->context;
1318         i = c->inst;
1319
1320         if (unlikely(atomic_read(&i->tainted)))
1321                 return -ENODEV;
1322
1323         nq_hdm_mbo(mbo);
1324         return 0;
1325 }
1326 EXPORT_SYMBOL_GPL(most_submit_mbo);
1327
1328 /**
1329  * most_write_completion - write completion handler
1330  * @mbo: pointer to MBO
1331  *
1332  * This recycles the MBO for further usage. In case the channel has been
1333  * poisoned, the MBO is scheduled to be trashed.
1334  */
1335 static void most_write_completion(struct mbo *mbo)
1336 {
1337         struct most_c_obj *c;
1338
1339         BUG_ON((!mbo) || (!mbo->context));
1340
1341         c = mbo->context;
1342         if (mbo->status == MBO_E_INVAL)
1343                 pr_info("WARN: Tx MBO status: invalid\n");
1344         if (unlikely((c->is_poisoned == true) || (mbo->status == MBO_E_CLOSE)))
1345                 trash_mbo(mbo);
1346         else
1347                 arm_mbo(mbo);
1348 }
1349
1350 /**
1351  * get_channel_by_iface - get pointer to channel object
1352  * @iface: pointer to interface instance
1353  * @id: channel ID
1354  *
1355  * This retrieves a pointer to a channel of the given interface and channel ID.
1356  */
1357 static struct
1358 most_c_obj *get_channel_by_iface(struct most_interface *iface, int id)
1359 {
1360         struct most_inst_obj *i;
1361
1362         if (unlikely(!iface)) {
1363                 pr_err("Bad interface\n");
1364                 return NULL;
1365         }
1366         if (unlikely((id < 0) || (id >= iface->num_channels))) {
1367                 pr_err("Channel index (%d) out of range\n", id);
1368                 return NULL;
1369         }
1370         i = iface->priv;
1371         if (unlikely(!i)) {
1372                 pr_err("interface is not registered\n");
1373                 return NULL;
1374         }
1375         return i->channel[id];
1376 }
1377
1378 /**
1379  * most_get_mbo - get pointer to an MBO of pool
1380  * @iface: pointer to interface instance
1381  * @id: channel ID
1382  *
1383  * This attempts to get a free buffer out of the channel fifo.
1384  * Returns a pointer to MBO on success or NULL otherwise.
1385  */
1386 struct mbo *most_get_mbo(struct most_interface *iface, int id)
1387 {
1388         struct mbo *mbo;
1389         struct most_c_obj *c;
1390         unsigned long flags;
1391
1392         c = get_channel_by_iface(iface, id);
1393         if (unlikely(!c))
1394                 return NULL;
1395         spin_lock_irqsave(&c->fifo_lock, flags);
1396         if (list_empty(&c->fifo)) {
1397                 spin_unlock_irqrestore(&c->fifo_lock, flags);
1398                 return NULL;
1399         }
1400         mbo = list_pop_mbo(&c->fifo);
1401         spin_unlock_irqrestore(&c->fifo_lock, flags);
1402         mbo->buffer_length = c->cfg.buffer_size;
1403         return mbo;
1404 }
1405 EXPORT_SYMBOL_GPL(most_get_mbo);
1406
1407
1408 /**
1409  * most_put_mbo - return buffer to pool
1410  * @mbo: buffer object
1411  */
1412 void most_put_mbo(struct mbo *mbo)
1413 {
1414         struct most_c_obj *c;
1415         struct most_inst_obj *i;
1416
1417         c = mbo->context;
1418         i = c->inst;
1419
1420         if (unlikely(atomic_read(&i->tainted))) {
1421                 mbo->status = MBO_E_CLOSE;
1422                 trash_mbo(mbo);
1423                 return;
1424         }
1425         if (c->cfg.direction == MOST_CH_TX) {
1426                 arm_mbo(mbo);
1427                 return;
1428         }
1429         nq_hdm_mbo(mbo);
1430         atomic_inc(&c->mbo_nq_level);
1431 }
1432 EXPORT_SYMBOL_GPL(most_put_mbo);
1433
1434 /**
1435  * most_read_completion - read completion handler
1436  * @mbo: pointer to MBO
1437  *
1438  * This function is called by the HDM when data has been received from the
1439  * hardware and copied to the buffer of the MBO.
1440  *
1441  * In case the channel has been poisoned it puts the buffer in the trash queue.
1442  * Otherwise, it passes the buffer to an AIM for further processing.
1443  */
1444 static void most_read_completion(struct mbo *mbo)
1445 {
1446         struct most_c_obj *c;
1447
1448         c = mbo->context;
1449         if (unlikely((c->is_poisoned == true) || (mbo->status == MBO_E_CLOSE)))
1450                 goto release_mbo;
1451
1452         if (mbo->status == MBO_E_INVAL) {
1453                 nq_hdm_mbo(mbo);
1454                 atomic_inc(&c->mbo_nq_level);
1455                 return;
1456         }
1457
1458         if (atomic_sub_and_test(1, &c->mbo_nq_level)) {
1459                 pr_info("WARN: rx device out of buffers\n");
1460                 c->is_starving = 1;
1461         }
1462
1463         if (c->first_aim && c->first_aim->rx_completion &&
1464             c->first_aim->rx_completion(mbo) == 0)
1465                 return;
1466         if (c->second_aim && c->second_aim->rx_completion &&
1467             c->second_aim->rx_completion(mbo) == 0)
1468                 return;
1469         pr_info("WARN: no driver linked with this channel\n");
1470         mbo->status = MBO_E_CLOSE;
1471 release_mbo:
1472         trash_mbo(mbo);
1473 }
1474
1475 /**
1476  * most_start_channel - prepares a channel for communication
1477  * @iface: pointer to interface instance
1478  * @id: channel ID
1479  *
1480  * This prepares the channel for usage. Cross-checks whether the
1481  * channel's been properly configured.
1482  *
1483  * Returns 0 on success or error code otherwise.
1484  */
1485 int most_start_channel(struct most_interface *iface, int id)
1486 {
1487         int num_buffer;
1488         int ret;
1489         struct most_c_obj *c = get_channel_by_iface(iface, id);
1490
1491         if (unlikely(!c))
1492                 return -EINVAL;
1493
1494         if (c->is_started)
1495                 return -EBUSY;
1496
1497         if (!try_module_get(iface->mod)) {
1498                 pr_info("failed to acquire HDM lock\n");
1499                 return -ENOLCK;
1500         }
1501         modref++;
1502
1503         c->cfg.extra_len = 0;
1504         if (c->iface->configure(c->iface, c->channel_id, &c->cfg)) {
1505                 pr_info("channel configuration failed. Go check settings...\n");
1506                 ret = -EINVAL;
1507                 goto error;
1508         }
1509
1510         init_waitqueue_head(&c->hdm_fifo_wq);
1511
1512         if (c->cfg.direction == MOST_CH_RX)
1513                 num_buffer = arm_mbo_chain(c, c->cfg.direction,
1514                                            most_read_completion);
1515         else
1516                 num_buffer = arm_mbo_chain(c, c->cfg.direction,
1517                                            most_write_completion);
1518         if (unlikely(0 == num_buffer)) {
1519                 pr_info("failed to allocate memory\n");
1520                 ret = -ENOMEM;
1521                 goto error;
1522         }
1523
1524         ret = run_enqueue_thread(c, id);
1525         if (ret)
1526                 goto error;
1527
1528         c->is_started = true;
1529         c->is_starving = 0;
1530         atomic_set(&c->mbo_ref, num_buffer);
1531         return 0;
1532 error:
1533         if (iface->mod)
1534                 module_put(iface->mod);
1535         modref--;
1536         return ret;
1537 }
1538 EXPORT_SYMBOL_GPL(most_start_channel);
1539
1540 /**
1541  * most_stop_channel - stops a running channel
1542  * @iface: pointer to interface instance
1543  * @id: channel ID
1544  */
1545 int most_stop_channel(struct most_interface *iface, int id)
1546 {
1547         struct most_c_obj *c;
1548
1549         if (unlikely((!iface) || (id >= iface->num_channels) || (id < 0))) {
1550                 pr_err("Bad interface or index out of range\n");
1551                 return -EINVAL;
1552         }
1553         c = get_channel_by_iface(iface, id);
1554         if (unlikely(!c))
1555                 return -EINVAL;
1556
1557         if (!c->is_started)
1558                 return 0;
1559
1560         /* FIXME: we need to know calling AIM to reset only one link */
1561         c->first_aim = NULL;
1562         c->second_aim = NULL;
1563         /* do not go into recursion calling aim->disconnect_channel */
1564
1565         mutex_lock(&c->stop_task_mutex);
1566         if (c->hdm_enqueue_task)
1567                 kthread_stop(c->hdm_enqueue_task);
1568         c->hdm_enqueue_task = NULL;
1569         mutex_unlock(&c->stop_task_mutex);
1570
1571         mutex_lock(&deregister_mutex);
1572         if (atomic_read(&c->inst->tainted)) {
1573                 mutex_unlock(&deregister_mutex);
1574                 return -ENODEV;
1575         }
1576         mutex_unlock(&deregister_mutex);
1577
1578         if (iface->mod && modref) {
1579                 module_put(iface->mod);
1580                 modref--;
1581         }
1582
1583         c->is_poisoned = true;
1584         if (c->iface->poison_channel(c->iface, c->channel_id)) {
1585                 pr_err("Cannot stop channel %d of mdev %s\n", c->channel_id,
1586                        c->iface->description);
1587                 return -EAGAIN;
1588         }
1589         flush_trash_fifo(c);
1590         flush_channel_fifos(c);
1591
1592 #ifdef CMPL_INTERRUPTIBLE
1593         if (wait_for_completion_interruptible(&c->cleanup)) {
1594                 pr_info("Interrupted while clean up ch %d\n", c->channel_id);
1595                 return -EINTR;
1596         }
1597 #else
1598         wait_for_completion(&c->cleanup);
1599 #endif
1600         c->is_poisoned = false;
1601         c->is_started = false;
1602         return 0;
1603 }
1604 EXPORT_SYMBOL_GPL(most_stop_channel);
1605
1606 /**
1607  * most_register_aim - registers an AIM (driver) with the core
1608  * @aim: instance of AIM to be registered
1609  */
1610 int most_register_aim(struct most_aim *aim)
1611 {
1612         struct most_aim_obj *aim_obj;
1613
1614         if (!aim) {
1615                 pr_err("Bad driver\n");
1616                 return -EINVAL;
1617         }
1618         aim_obj = create_most_aim_obj(aim->name);
1619         if (!aim_obj) {
1620                 pr_info("failed to alloc driver object\n");
1621                 return -ENOMEM;
1622         }
1623         aim_obj->driver = aim;
1624         aim->context = aim_obj;
1625         pr_info("registered new application interfacing module %s\n",
1626                 aim->name);
1627         list_add_tail(&aim_obj->list, &aim_list);
1628         return 0;
1629 }
1630 EXPORT_SYMBOL_GPL(most_register_aim);
1631
1632 /**
1633  * most_deregister_aim - deregisters an AIM (driver) with the core
1634  * @aim: AIM to be removed
1635  */
1636 int most_deregister_aim(struct most_aim *aim)
1637 {
1638         struct most_aim_obj *aim_obj;
1639         struct most_c_obj *c, *tmp;
1640         struct most_inst_obj *i, *i_tmp;
1641
1642         if (!aim) {
1643                 pr_err("Bad driver\n");
1644                 return -EINVAL;
1645         }
1646
1647         aim_obj = aim->context;
1648         if (!aim_obj) {
1649                 pr_info("driver not registered.\n");
1650                 return -EINVAL;
1651         }
1652         list_for_each_entry_safe(i, i_tmp, &instance_list, list) {
1653                 list_for_each_entry_safe(c, tmp, &i->channel_list, list) {
1654                         if (c->first_aim == aim || c->second_aim == aim)
1655                                 aim->disconnect_channel(
1656                                         c->iface, c->channel_id);
1657                         if (c->first_aim == aim)
1658                                 c->first_aim = NULL;
1659                         if (c->second_aim == aim)
1660                                 c->second_aim = NULL;
1661                 }
1662         }
1663         list_del(&aim_obj->list);
1664         destroy_most_aim_obj(aim_obj);
1665         pr_info("deregistering application interfacing module %s\n", aim->name);
1666         return 0;
1667 }
1668 EXPORT_SYMBOL_GPL(most_deregister_aim);
1669
1670 /**
1671  * most_register_interface - registers an interface with core
1672  * @iface: pointer to the instance of the interface description.
1673  *
1674  * Allocates and initializes a new interface instance and all of its channels.
1675  * Returns a pointer to kobject or an error pointer.
1676  */
1677 struct kobject *most_register_interface(struct most_interface *iface)
1678 {
1679         unsigned int i;
1680         int id;
1681         char name[STRING_SIZE];
1682         char channel_name[STRING_SIZE];
1683         struct most_c_obj *c;
1684         struct most_inst_obj *inst;
1685
1686         if (!iface || !iface->enqueue || !iface->configure ||
1687             !iface->poison_channel || (iface->num_channels > MAX_CHANNELS)) {
1688                 pr_err("Bad interface or channel overflow\n");
1689                 return ERR_PTR(-EINVAL);
1690         }
1691
1692         id = ida_simple_get(&mdev_id, 0, 0, GFP_KERNEL);
1693         if (id < 0) {
1694                 pr_info("Failed to alloc mdev ID\n");
1695                 return ERR_PTR(id);
1696         }
1697         snprintf(name, STRING_SIZE, "mdev%d", id);
1698
1699         inst = create_most_inst_obj(name);
1700         if (!inst) {
1701                 pr_info("Failed to allocate interface instance\n");
1702                 return ERR_PTR(-ENOMEM);
1703         }
1704
1705         iface->priv = inst;
1706         INIT_LIST_HEAD(&inst->channel_list);
1707         inst->iface = iface;
1708         inst->dev_id = id;
1709         atomic_set(&inst->tainted, 0);
1710         list_add_tail(&inst->list, &instance_list);
1711
1712         for (i = 0; i < iface->num_channels; i++) {
1713                 const char *name_suffix = iface->channel_vector[i].name_suffix;
1714
1715                 if (!name_suffix)
1716                         snprintf(channel_name, STRING_SIZE, "ch%d", i);
1717                 else if (name_suffix[0] == '@')
1718                         snprintf(channel_name, STRING_SIZE, "ch%d%s", i,
1719                                  name_suffix);
1720                 else
1721                         snprintf(channel_name, STRING_SIZE, "%s", name_suffix);
1722
1723                 /* this increments the reference count of this instance */
1724                 c = create_most_c_obj(channel_name, &inst->kobj);
1725                 if (!c)
1726                         goto free_instance;
1727                 inst->channel[i] = c;
1728                 c->is_starving = 0;
1729                 c->iface = iface;
1730                 c->inst = inst;
1731                 c->channel_id = i;
1732                 c->keep_mbo = false;
1733                 c->enqueue_halt = false;
1734                 c->is_poisoned = false;
1735                 c->is_started = false;
1736                 c->cfg.direction = 0;
1737                 c->cfg.data_type = 0;
1738                 c->cfg.num_buffers = 0;
1739                 c->cfg.buffer_size = 0;
1740                 c->cfg.subbuffer_size = 0;
1741                 c->cfg.packets_per_xact = 0;
1742                 spin_lock_init(&c->fifo_lock);
1743                 INIT_LIST_HEAD(&c->fifo);
1744                 INIT_LIST_HEAD(&c->trash_fifo);
1745                 INIT_LIST_HEAD(&c->halt_fifo);
1746                 init_completion(&c->cleanup);
1747                 atomic_set(&c->mbo_ref, 0);
1748                 mutex_init(&c->stop_task_mutex);
1749                 list_add_tail(&c->list, &inst->channel_list);
1750         }
1751         pr_info("registered new MOST device mdev%d (%s)\n",
1752                 inst->dev_id, iface->description);
1753         return &inst->kobj;
1754
1755 free_instance:
1756         pr_info("Failed allocate channel(s)\n");
1757         list_del(&inst->list);
1758         destroy_most_inst_obj(inst);
1759         return ERR_PTR(-ENOMEM);
1760 }
1761 EXPORT_SYMBOL_GPL(most_register_interface);
1762
1763 /**
1764  * most_deregister_interface - deregisters an interface with core
1765  * @iface: pointer to the interface instance description.
1766  *
1767  * Before removing an interface instance from the list, all running
1768  * channels are stopped and poisoned.
1769  */
1770 void most_deregister_interface(struct most_interface *iface)
1771 {
1772         struct most_inst_obj *i = iface->priv;
1773         struct most_c_obj *c;
1774
1775         mutex_lock(&deregister_mutex);
1776         if (unlikely(!i)) {
1777                 pr_info("Bad Interface\n");
1778                 mutex_unlock(&deregister_mutex);
1779                 return;
1780         }
1781         pr_info("deregistering MOST device %s (%s)\n", i->kobj.name,
1782                 iface->description);
1783
1784         atomic_set(&i->tainted, 1);
1785         mutex_unlock(&deregister_mutex);
1786
1787         while (modref) {
1788                 if (iface->mod && modref)
1789                         module_put(iface->mod);
1790                 modref--;
1791         }
1792
1793         list_for_each_entry(c, &i->channel_list, list) {
1794                 if (!c->is_started)
1795                         continue;
1796
1797                 mutex_lock(&c->stop_task_mutex);
1798                 if (c->hdm_enqueue_task)
1799                         kthread_stop(c->hdm_enqueue_task);
1800                 c->hdm_enqueue_task = NULL;
1801                 mutex_unlock(&c->stop_task_mutex);
1802
1803                 if (iface->poison_channel(iface, c->channel_id))
1804                         pr_err("Can't poison channel %d\n", c->channel_id);
1805         }
1806         ida_simple_remove(&mdev_id, i->dev_id);
1807         list_del(&i->list);
1808         destroy_most_inst_obj(i);
1809 }
1810 EXPORT_SYMBOL_GPL(most_deregister_interface);
1811
1812 /**
1813  * most_stop_enqueue - prevents core from enqueueing MBOs
1814  * @iface: pointer to interface
1815  * @id: channel id
1816  *
1817  * This is called by an HDM that _cannot_ attend to its duties and
1818  * is imminent to get run over by the core. The core is not going to
1819  * enqueue any further packets unless the flagging HDM calls
1820  * most_resume enqueue().
1821  */
1822 void most_stop_enqueue(struct most_interface *iface, int id)
1823 {
1824         struct most_c_obj *c = get_channel_by_iface(iface, id);
1825
1826         if (likely(c))
1827                 c->enqueue_halt = true;
1828 }
1829 EXPORT_SYMBOL_GPL(most_stop_enqueue);
1830
1831 /**
1832  * most_resume_enqueue - allow core to enqueue MBOs again
1833  * @iface: pointer to interface
1834  * @id: channel id
1835  *
1836  * This clears the enqueue halt flag and enqueues all MBOs currently
1837  * sitting in the wait fifo.
1838  */
1839 void most_resume_enqueue(struct most_interface *iface, int id)
1840 {
1841         struct most_c_obj *c = get_channel_by_iface(iface, id);
1842
1843         if (unlikely(!c))
1844                 return;
1845         c->enqueue_halt = false;
1846
1847         wake_up_interruptible(&c->hdm_fifo_wq);
1848 }
1849 EXPORT_SYMBOL_GPL(most_resume_enqueue);
1850
1851 static int __init most_init(void)
1852 {
1853         pr_info("init()\n");
1854         INIT_LIST_HEAD(&instance_list);
1855         INIT_LIST_HEAD(&aim_list);
1856         mutex_init(&deregister_mutex);
1857         ida_init(&mdev_id);
1858
1859         if (bus_register(&most_bus)) {
1860                 pr_info("Cannot register most bus\n");
1861                 goto exit;
1862         }
1863
1864         most_class = class_create(THIS_MODULE, "most");
1865         if (IS_ERR(most_class)) {
1866                 pr_info("No udev support.\n");
1867                 goto exit_bus;
1868         }
1869         if (driver_register(&mostcore)) {
1870                 pr_info("Cannot register core driver\n");
1871                 goto exit_class;
1872         }
1873
1874         class_glue_dir =
1875                 device_create(most_class, NULL, 0, NULL, "mostcore");
1876         if (!class_glue_dir)
1877                 goto exit_driver;
1878
1879         most_aim_kset =
1880                 kset_create_and_add("aims", NULL, &class_glue_dir->kobj);
1881         if (!most_aim_kset)
1882                 goto exit_class_container;
1883
1884         most_inst_kset =
1885                 kset_create_and_add("devices", NULL, &class_glue_dir->kobj);
1886         if (!most_inst_kset)
1887                 goto exit_driver_kset;
1888
1889         return 0;
1890
1891 exit_driver_kset:
1892         kset_unregister(most_aim_kset);
1893 exit_class_container:
1894         device_destroy(most_class, 0);
1895 exit_driver:
1896         driver_unregister(&mostcore);
1897 exit_class:
1898         class_destroy(most_class);
1899 exit_bus:
1900         bus_unregister(&most_bus);
1901 exit:
1902         return -ENOMEM;
1903 }
1904
1905 static void __exit most_exit(void)
1906 {
1907         struct most_inst_obj *i, *i_tmp;
1908         struct most_aim_obj *d, *d_tmp;
1909
1910         pr_info("exit core module\n");
1911         list_for_each_entry_safe(d, d_tmp, &aim_list, list) {
1912                 destroy_most_aim_obj(d);
1913         }
1914
1915         list_for_each_entry_safe(i, i_tmp, &instance_list, list) {
1916                 list_del(&i->list);
1917                 destroy_most_inst_obj(i);
1918         }
1919         kset_unregister(most_inst_kset);
1920         kset_unregister(most_aim_kset);
1921         device_destroy(most_class, 0);
1922         driver_unregister(&mostcore);
1923         class_destroy(most_class);
1924         bus_unregister(&most_bus);
1925         ida_destroy(&mdev_id);
1926 }
1927
1928 module_init(most_init);
1929 module_exit(most_exit);
1930 MODULE_LICENSE("GPL");
1931 MODULE_AUTHOR("Christian Gromm <christian.gromm@microchip.com>");
1932 MODULE_DESCRIPTION("Core module of stacked MOST Linux driver");