drivers/staging/most/core.c

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This source file includes following definitions.
most_free_mbo_coherent
flush_channel_fifos
flush_trash_fifo
available_directions_show
available_datatypes_show
number_of_packet_buffers_show
number_of_stream_buffers_show
size_of_packet_buffer_show
size_of_stream_buffer_show
channel_starving_show
set_number_of_buffers_show
set_buffer_size_show
set_direction_show
set_datatype_show
set_subbuffer_size_show
set_packets_per_xact_show
set_dbr_size_show
channel_attr_is_visible
description_show
interface_show
match_component
print_links
links_show
components_show
split_string
get_channel
link_channel_to_component
most_set_cfg_buffer_size
most_set_cfg_subbuffer_size
most_set_cfg_dbr_size
most_set_cfg_num_buffers
most_set_cfg_datatype
most_set_cfg_direction
most_set_cfg_packets_xact
most_cfg_complete
most_add_link
remove_link_store
most_remove_link
most_match
trash_mbo
hdm_mbo_ready
nq_hdm_mbo
hdm_enqueue_thread
run_enqueue_thread
arm_mbo
arm_mbo_chain
most_submit_mbo
most_write_completion
channel_has_mbo
most_get_mbo
most_put_mbo
most_read_completion
most_start_channel
most_stop_channel
most_register_component
disconnect_channels
most_deregister_component
release_interface
release_channel
most_register_interface
most_deregister_interface
most_stop_enqueue
most_resume_enqueue
release_most_sub
most_init
most_exit
   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * core.c - Implementation of core module of MOST Linux driver stack
   4  *
   5  * Copyright (C) 2013-2015 Microchip Technology Germany II GmbH & Co. KG
   6  */
   7 
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9 #include <linux/module.h>
  10 #include <linux/fs.h>
  11 #include <linux/slab.h>
  12 #include <linux/init.h>
  13 #include <linux/device.h>
  14 #include <linux/list.h>
  15 #include <linux/poll.h>
  16 #include <linux/wait.h>
  17 #include <linux/kobject.h>
  18 #include <linux/mutex.h>
  19 #include <linux/completion.h>
  20 #include <linux/sysfs.h>
  21 #include <linux/kthread.h>
  22 #include <linux/dma-mapping.h>
  23 #include <linux/idr.h>
  24 #include <most/core.h>
  25 
  26 #define MAX_CHANNELS    64
  27 #define STRING_SIZE     80
  28 
  29 static struct ida mdev_id;
  30 static int dummy_num_buffers;
  31 
  32 static struct mostcore {
  33         struct device dev;
  34         struct device_driver drv;
  35         struct bus_type bus;
  36         struct list_head comp_list;
  37 } mc;
  38 
  39 #define to_driver(d) container_of(d, struct mostcore, drv)
  40 
  41 struct pipe {
  42         struct core_component *comp;
  43         int refs;
  44         int num_buffers;
  45 };
  46 
  47 struct most_channel {
  48         struct device dev;
  49         struct completion cleanup;
  50         atomic_t mbo_ref;
  51         atomic_t mbo_nq_level;
  52         u16 channel_id;
  53         char name[STRING_SIZE];
  54         bool is_poisoned;
  55         struct mutex start_mutex;
  56         struct mutex nq_mutex; /* nq thread synchronization */
  57         int is_starving;
  58         struct most_interface *iface;
  59         struct most_channel_config cfg;
  60         bool keep_mbo;
  61         bool enqueue_halt;
  62         struct list_head fifo;
  63         spinlock_t fifo_lock;
  64         struct list_head halt_fifo;
  65         struct list_head list;
  66         struct pipe pipe0;
  67         struct pipe pipe1;
  68         struct list_head trash_fifo;
  69         struct task_struct *hdm_enqueue_task;
  70         wait_queue_head_t hdm_fifo_wq;
  71 
  72 };
  73 
  74 #define to_channel(d) container_of(d, struct most_channel, dev)
  75 
  76 struct interface_private {
  77         int dev_id;
  78         char name[STRING_SIZE];
  79         struct most_channel *channel[MAX_CHANNELS];
  80         struct list_head channel_list;
  81 };
  82 
  83 static const struct {
  84         int most_ch_data_type;
  85         const char *name;
  86 } ch_data_type[] = {
  87         { MOST_CH_CONTROL, "control\n" },
  88         { MOST_CH_ASYNC, "async\n" },
  89         { MOST_CH_SYNC, "sync\n" },
  90         { MOST_CH_ISOC, "isoc\n"},
  91         { MOST_CH_ISOC, "isoc_avp\n"},
  92 };
  93 
  94 /**
  95  * list_pop_mbo - retrieves the first MBO of the list and removes it
  96  * @ptr: the list head to grab the MBO from.
  97  */
  98 #define list_pop_mbo(ptr)                                               \
  99 ({                                                                      \
 100         struct mbo *_mbo = list_first_entry(ptr, struct mbo, list);     \
 101         list_del(&_mbo->list);                                          \
 102         _mbo;                                                           \
 103 })
 104 
 105 /**
 106  * most_free_mbo_coherent - free an MBO and its coherent buffer
 107  * @mbo: most buffer
 108  */
 109 static void most_free_mbo_coherent(struct mbo *mbo)
 110 {
 111         struct most_channel *c = mbo->context;
 112         u16 const coherent_buf_size = c->cfg.buffer_size + c->cfg.extra_len;
 113 
 114         if (c->iface->dma_free)
 115                 c->iface->dma_free(mbo, coherent_buf_size);
 116         else
 117                 kfree(mbo->virt_address);
 118         kfree(mbo);
 119         if (atomic_sub_and_test(1, &c->mbo_ref))
 120                 complete(&c->cleanup);
 121 }
 122 
 123 /**
 124  * flush_channel_fifos - clear the channel fifos
 125  * @c: pointer to channel object
 126  */
 127 static void flush_channel_fifos(struct most_channel *c)
 128 {
 129         unsigned long flags, hf_flags;
 130         struct mbo *mbo, *tmp;
 131 
 132         if (list_empty(&c->fifo) && list_empty(&c->halt_fifo))
 133                 return;
 134 
 135         spin_lock_irqsave(&c->fifo_lock, flags);
 136         list_for_each_entry_safe(mbo, tmp, &c->fifo, list) {
 137                 list_del(&mbo->list);
 138                 spin_unlock_irqrestore(&c->fifo_lock, flags);
 139                 most_free_mbo_coherent(mbo);
 140                 spin_lock_irqsave(&c->fifo_lock, flags);
 141         }
 142         spin_unlock_irqrestore(&c->fifo_lock, flags);
 143 
 144         spin_lock_irqsave(&c->fifo_lock, hf_flags);
 145         list_for_each_entry_safe(mbo, tmp, &c->halt_fifo, list) {
 146                 list_del(&mbo->list);
 147                 spin_unlock_irqrestore(&c->fifo_lock, hf_flags);
 148                 most_free_mbo_coherent(mbo);
 149                 spin_lock_irqsave(&c->fifo_lock, hf_flags);
 150         }
 151         spin_unlock_irqrestore(&c->fifo_lock, hf_flags);
 152 
 153         if (unlikely((!list_empty(&c->fifo) || !list_empty(&c->halt_fifo))))
 154                 pr_info("WARN: fifo | trash fifo not empty\n");
 155 }
 156 
 157 /**
 158  * flush_trash_fifo - clear the trash fifo
 159  * @c: pointer to channel object
 160  */
 161 static int flush_trash_fifo(struct most_channel *c)
 162 {
 163         struct mbo *mbo, *tmp;
 164         unsigned long flags;
 165 
 166         spin_lock_irqsave(&c->fifo_lock, flags);
 167         list_for_each_entry_safe(mbo, tmp, &c->trash_fifo, list) {
 168                 list_del(&mbo->list);
 169                 spin_unlock_irqrestore(&c->fifo_lock, flags);
 170                 most_free_mbo_coherent(mbo);
 171                 spin_lock_irqsave(&c->fifo_lock, flags);
 172         }
 173         spin_unlock_irqrestore(&c->fifo_lock, flags);
 174         return 0;
 175 }
 176 
 177 static ssize_t available_directions_show(struct device *dev,
 178                                          struct device_attribute *attr,
 179                                          char *buf)
 180 {
 181         struct most_channel *c = to_channel(dev);
 182         unsigned int i = c->channel_id;
 183 
 184         strcpy(buf, "");
 185         if (c->iface->channel_vector[i].direction & MOST_CH_RX)
 186                 strcat(buf, "rx ");
 187         if (c->iface->channel_vector[i].direction & MOST_CH_TX)
 188                 strcat(buf, "tx ");
 189         strcat(buf, "\n");
 190         return strlen(buf);
 191 }
 192 
 193 static ssize_t available_datatypes_show(struct device *dev,
 194                                         struct device_attribute *attr,
 195                                         char *buf)
 196 {
 197         struct most_channel *c = to_channel(dev);
 198         unsigned int i = c->channel_id;
 199 
 200         strcpy(buf, "");
 201         if (c->iface->channel_vector[i].data_type & MOST_CH_CONTROL)
 202                 strcat(buf, "control ");
 203         if (c->iface->channel_vector[i].data_type & MOST_CH_ASYNC)
 204                 strcat(buf, "async ");
 205         if (c->iface->channel_vector[i].data_type & MOST_CH_SYNC)
 206                 strcat(buf, "sync ");
 207         if (c->iface->channel_vector[i].data_type & MOST_CH_ISOC)
 208                 strcat(buf, "isoc ");
 209         strcat(buf, "\n");
 210         return strlen(buf);
 211 }
 212 
 213 static ssize_t number_of_packet_buffers_show(struct device *dev,
 214                                              struct device_attribute *attr,
 215                                              char *buf)
 216 {
 217         struct most_channel *c = to_channel(dev);
 218         unsigned int i = c->channel_id;
 219 
 220         return snprintf(buf, PAGE_SIZE, "%d\n",
 221                         c->iface->channel_vector[i].num_buffers_packet);
 222 }
 223 
 224 static ssize_t number_of_stream_buffers_show(struct device *dev,
 225                                              struct device_attribute *attr,
 226                                              char *buf)
 227 {
 228         struct most_channel *c = to_channel(dev);
 229         unsigned int i = c->channel_id;
 230 
 231         return snprintf(buf, PAGE_SIZE, "%d\n",
 232                         c->iface->channel_vector[i].num_buffers_streaming);
 233 }
 234 
 235 static ssize_t size_of_packet_buffer_show(struct device *dev,
 236                                           struct device_attribute *attr,
 237                                           char *buf)
 238 {
 239         struct most_channel *c = to_channel(dev);
 240         unsigned int i = c->channel_id;
 241 
 242         return snprintf(buf, PAGE_SIZE, "%d\n",
 243                         c->iface->channel_vector[i].buffer_size_packet);
 244 }
 245 
 246 static ssize_t size_of_stream_buffer_show(struct device *dev,
 247                                           struct device_attribute *attr,
 248                                           char *buf)
 249 {
 250         struct most_channel *c = to_channel(dev);
 251         unsigned int i = c->channel_id;
 252 
 253         return snprintf(buf, PAGE_SIZE, "%d\n",
 254                         c->iface->channel_vector[i].buffer_size_streaming);
 255 }
 256 
 257 static ssize_t channel_starving_show(struct device *dev,
 258                                      struct device_attribute *attr,
 259                                      char *buf)
 260 {
 261         struct most_channel *c = to_channel(dev);
 262 
 263         return snprintf(buf, PAGE_SIZE, "%d\n", c->is_starving);
 264 }
 265 
 266 static ssize_t set_number_of_buffers_show(struct device *dev,
 267                                           struct device_attribute *attr,
 268                                           char *buf)
 269 {
 270         struct most_channel *c = to_channel(dev);
 271 
 272         return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.num_buffers);
 273 }
 274 
 275 static ssize_t set_buffer_size_show(struct device *dev,
 276                                     struct device_attribute *attr,
 277                                     char *buf)
 278 {
 279         struct most_channel *c = to_channel(dev);
 280 
 281         return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.buffer_size);
 282 }
 283 
 284 static ssize_t set_direction_show(struct device *dev,
 285                                   struct device_attribute *attr,
 286                                   char *buf)
 287 {
 288         struct most_channel *c = to_channel(dev);
 289 
 290         if (c->cfg.direction & MOST_CH_TX)
 291                 return snprintf(buf, PAGE_SIZE, "tx\n");
 292         else if (c->cfg.direction & MOST_CH_RX)
 293                 return snprintf(buf, PAGE_SIZE, "rx\n");
 294         return snprintf(buf, PAGE_SIZE, "unconfigured\n");
 295 }
 296 
 297 static ssize_t set_datatype_show(struct device *dev,
 298                                  struct device_attribute *attr,
 299                                  char *buf)
 300 {
 301         int i;
 302         struct most_channel *c = to_channel(dev);
 303 
 304         for (i = 0; i < ARRAY_SIZE(ch_data_type); i++) {
 305                 if (c->cfg.data_type & ch_data_type[i].most_ch_data_type)
 306                         return snprintf(buf, PAGE_SIZE, "%s",
 307                                         ch_data_type[i].name);
 308         }
 309         return snprintf(buf, PAGE_SIZE, "unconfigured\n");
 310 }
 311 
 312 static ssize_t set_subbuffer_size_show(struct device *dev,
 313                                        struct device_attribute *attr,
 314                                        char *buf)
 315 {
 316         struct most_channel *c = to_channel(dev);
 317 
 318         return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.subbuffer_size);
 319 }
 320 
 321 static ssize_t set_packets_per_xact_show(struct device *dev,
 322                                          struct device_attribute *attr,
 323                                          char *buf)
 324 {
 325         struct most_channel *c = to_channel(dev);
 326 
 327         return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.packets_per_xact);
 328 }
 329 
 330 static ssize_t set_dbr_size_show(struct device *dev,
 331                                  struct device_attribute *attr, char *buf)
 332 {
 333         struct most_channel *c = to_channel(dev);
 334 
 335         return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.dbr_size);
 336 }
 337 
 338 #define to_dev_attr(a) container_of(a, struct device_attribute, attr)
 339 static umode_t channel_attr_is_visible(struct kobject *kobj,
 340                                        struct attribute *attr, int index)
 341 {
 342         struct device_attribute *dev_attr = to_dev_attr(attr);
 343         struct device *dev = kobj_to_dev(kobj);
 344         struct most_channel *c = to_channel(dev);
 345 
 346         if (!strcmp(dev_attr->attr.name, "set_dbr_size") &&
 347             (c->iface->interface != ITYPE_MEDIALB_DIM2))
 348                 return 0;
 349         if (!strcmp(dev_attr->attr.name, "set_packets_per_xact") &&
 350             (c->iface->interface != ITYPE_USB))
 351                 return 0;
 352 
 353         return attr->mode;
 354 }
 355 
 356 #define DEV_ATTR(_name)  (&dev_attr_##_name.attr)
 357 
 358 static DEVICE_ATTR_RO(available_directions);
 359 static DEVICE_ATTR_RO(available_datatypes);
 360 static DEVICE_ATTR_RO(number_of_packet_buffers);
 361 static DEVICE_ATTR_RO(number_of_stream_buffers);
 362 static DEVICE_ATTR_RO(size_of_stream_buffer);
 363 static DEVICE_ATTR_RO(size_of_packet_buffer);
 364 static DEVICE_ATTR_RO(channel_starving);
 365 static DEVICE_ATTR_RO(set_buffer_size);
 366 static DEVICE_ATTR_RO(set_number_of_buffers);
 367 static DEVICE_ATTR_RO(set_direction);
 368 static DEVICE_ATTR_RO(set_datatype);
 369 static DEVICE_ATTR_RO(set_subbuffer_size);
 370 static DEVICE_ATTR_RO(set_packets_per_xact);
 371 static DEVICE_ATTR_RO(set_dbr_size);
 372 
 373 static struct attribute *channel_attrs[] = {
 374         DEV_ATTR(available_directions),
 375         DEV_ATTR(available_datatypes),
 376         DEV_ATTR(number_of_packet_buffers),
 377         DEV_ATTR(number_of_stream_buffers),
 378         DEV_ATTR(size_of_stream_buffer),
 379         DEV_ATTR(size_of_packet_buffer),
 380         DEV_ATTR(channel_starving),
 381         DEV_ATTR(set_buffer_size),
 382         DEV_ATTR(set_number_of_buffers),
 383         DEV_ATTR(set_direction),
 384         DEV_ATTR(set_datatype),
 385         DEV_ATTR(set_subbuffer_size),
 386         DEV_ATTR(set_packets_per_xact),
 387         DEV_ATTR(set_dbr_size),
 388         NULL,
 389 };
 390 
 391 static struct attribute_group channel_attr_group = {
 392         .attrs = channel_attrs,
 393         .is_visible = channel_attr_is_visible,
 394 };
 395 
 396 static const struct attribute_group *channel_attr_groups[] = {
 397         &channel_attr_group,
 398         NULL,
 399 };
 400 
 401 static ssize_t description_show(struct device *dev,
 402                                 struct device_attribute *attr,
 403                                 char *buf)
 404 {
 405         struct most_interface *iface = to_most_interface(dev);
 406 
 407         return snprintf(buf, PAGE_SIZE, "%s\n", iface->description);
 408 }
 409 
 410 static ssize_t interface_show(struct device *dev,
 411                               struct device_attribute *attr,
 412                               char *buf)
 413 {
 414         struct most_interface *iface = to_most_interface(dev);
 415 
 416         switch (iface->interface) {
 417         case ITYPE_LOOPBACK:
 418                 return snprintf(buf, PAGE_SIZE, "loopback\n");
 419         case ITYPE_I2C:
 420                 return snprintf(buf, PAGE_SIZE, "i2c\n");
 421         case ITYPE_I2S:
 422                 return snprintf(buf, PAGE_SIZE, "i2s\n");
 423         case ITYPE_TSI:
 424                 return snprintf(buf, PAGE_SIZE, "tsi\n");
 425         case ITYPE_HBI:
 426                 return snprintf(buf, PAGE_SIZE, "hbi\n");
 427         case ITYPE_MEDIALB_DIM:
 428                 return snprintf(buf, PAGE_SIZE, "mlb_dim\n");
 429         case ITYPE_MEDIALB_DIM2:
 430                 return snprintf(buf, PAGE_SIZE, "mlb_dim2\n");
 431         case ITYPE_USB:
 432                 return snprintf(buf, PAGE_SIZE, "usb\n");
 433         case ITYPE_PCIE:
 434                 return snprintf(buf, PAGE_SIZE, "pcie\n");
 435         }
 436         return snprintf(buf, PAGE_SIZE, "unknown\n");
 437 }
 438 
 439 static DEVICE_ATTR_RO(description);
 440 static DEVICE_ATTR_RO(interface);
 441 
 442 static struct attribute *interface_attrs[] = {
 443         DEV_ATTR(description),
 444         DEV_ATTR(interface),
 445         NULL,
 446 };
 447 
 448 static struct attribute_group interface_attr_group = {
 449         .attrs = interface_attrs,
 450 };
 451 
 452 static const struct attribute_group *interface_attr_groups[] = {
 453         &interface_attr_group,
 454         NULL,
 455 };
 456 
 457 static struct core_component *match_component(char *name)
 458 {
 459         struct core_component *comp;
 460 
 461         list_for_each_entry(comp, &mc.comp_list, list) {
 462                 if (!strcmp(comp->name, name))
 463                         return comp;
 464         }
 465         return NULL;
 466 }
 467 
 468 struct show_links_data {
 469         int offs;
 470         char *buf;
 471 };
 472 
 473 static int print_links(struct device *dev, void *data)
 474 {
 475         struct show_links_data *d = data;
 476         int offs = d->offs;
 477         char *buf = d->buf;
 478         struct most_channel *c;
 479         struct most_interface *iface = to_most_interface(dev);
 480 
 481         list_for_each_entry(c, &iface->p->channel_list, list) {
 482                 if (c->pipe0.comp) {
 483                         offs += snprintf(buf + offs,
 484                                          PAGE_SIZE - offs,
 485                                          "%s:%s:%s\n",
 486                                          c->pipe0.comp->name,
 487                                          dev_name(&iface->dev),
 488                                          dev_name(&c->dev));
 489                 }
 490                 if (c->pipe1.comp) {
 491                         offs += snprintf(buf + offs,
 492                                          PAGE_SIZE - offs,
 493                                          "%s:%s:%s\n",
 494                                          c->pipe1.comp->name,
 495                                          dev_name(&iface->dev),
 496                                          dev_name(&c->dev));
 497                 }
 498         }
 499         d->offs = offs;
 500         return 0;
 501 }
 502 
 503 static ssize_t links_show(struct device_driver *drv, char *buf)
 504 {
 505         struct show_links_data d = { .buf = buf };
 506 
 507         bus_for_each_dev(&mc.bus, NULL, &d, print_links);
 508         return d.offs;
 509 }
 510 
 511 static ssize_t components_show(struct device_driver *drv, char *buf)
 512 {
 513         struct core_component *comp;
 514         int offs = 0;
 515 
 516         list_for_each_entry(comp, &mc.comp_list, list) {
 517                 offs += snprintf(buf + offs, PAGE_SIZE - offs, "%s\n",
 518                                  comp->name);
 519         }
 520         return offs;
 521 }
 522 
 523 /**
 524  * split_string - parses buf and extracts ':' separated substrings.
 525  *
 526  * @buf: complete string from attribute 'add_channel'
 527  * @a: storage for 1st substring (=interface name)
 528  * @b: storage for 2nd substring (=channel name)
 529  * @c: storage for 3rd substring (=component name)
 530  * @d: storage optional 4th substring (=user defined name)
 531  *
 532  * Examples:
 533  *
 534  * Input: "mdev0:ch6:cdev:my_channel\n" or
 535  *        "mdev0:ch6:cdev:my_channel"
 536  *
 537  * Output: *a -> "mdev0", *b -> "ch6", *c -> "cdev" *d -> "my_channel"
 538  *
 539  * Input: "mdev1:ep81:cdev\n"
 540  * Output: *a -> "mdev1", *b -> "ep81", *c -> "cdev" *d -> ""
 541  *
 542  * Input: "mdev1:ep81"
 543  * Output: *a -> "mdev1", *b -> "ep81", *c -> "cdev" *d == NULL
 544  */
 545 static int split_string(char *buf, char **a, char **b, char **c, char **d)
 546 {
 547         *a = strsep(&buf, ":");
 548         if (!*a)
 549                 return -EIO;
 550 
 551         *b = strsep(&buf, ":\n");
 552         if (!*b)
 553                 return -EIO;
 554 
 555         *c = strsep(&buf, ":\n");
 556         if (!*c)
 557                 return -EIO;
 558 
 559         if (d)
 560                 *d = strsep(&buf, ":\n");
 561 
 562         return 0;
 563 }
 564 
 565 /**
 566  * get_channel - get pointer to channel
 567  * @mdev: name of the device interface
 568  * @mdev_ch: name of channel
 569  */
 570 static struct most_channel *get_channel(char *mdev, char *mdev_ch)
 571 {
 572         struct device *dev = NULL;
 573         struct most_interface *iface;
 574         struct most_channel *c, *tmp;
 575 
 576         dev = bus_find_device_by_name(&mc.bus, NULL, mdev);
 577         if (!dev)
 578                 return NULL;
 579         iface = to_most_interface(dev);
 580         list_for_each_entry_safe(c, tmp, &iface->p->channel_list, list) {
 581                 if (!strcmp(dev_name(&c->dev), mdev_ch))
 582                         return c;
 583         }
 584         return NULL;
 585 }
 586 
 587 static
 588 inline int link_channel_to_component(struct most_channel *c,
 589                                      struct core_component *comp,
 590                                      char *name,
 591                                      char *comp_param)
 592 {
 593         int ret;
 594         struct core_component **comp_ptr;
 595 
 596         if (!c->pipe0.comp)
 597                 comp_ptr = &c->pipe0.comp;
 598         else if (!c->pipe1.comp)
 599                 comp_ptr = &c->pipe1.comp;
 600         else
 601                 return -ENOSPC;
 602 
 603         *comp_ptr = comp;
 604         ret = comp->probe_channel(c->iface, c->channel_id, &c->cfg, name,
 605                                   comp_param);
 606         if (ret) {
 607                 *comp_ptr = NULL;
 608                 return ret;
 609         }
 610         return 0;
 611 }
 612 
 613 int most_set_cfg_buffer_size(char *mdev, char *mdev_ch, u16 val)
 614 {
 615         struct most_channel *c = get_channel(mdev, mdev_ch);
 616 
 617         if (!c)
 618                 return -ENODEV;
 619         c->cfg.buffer_size = val;
 620         return 0;
 621 }
 622 
 623 int most_set_cfg_subbuffer_size(char *mdev, char *mdev_ch, u16 val)
 624 {
 625         struct most_channel *c = get_channel(mdev, mdev_ch);
 626 
 627         if (!c)
 628                 return -ENODEV;
 629         c->cfg.subbuffer_size = val;
 630         return 0;
 631 }
 632 
 633 int most_set_cfg_dbr_size(char *mdev, char *mdev_ch, u16 val)
 634 {
 635         struct most_channel *c = get_channel(mdev, mdev_ch);
 636 
 637         if (!c)
 638                 return -ENODEV;
 639         c->cfg.dbr_size = val;
 640         return 0;
 641 }
 642 
 643 int most_set_cfg_num_buffers(char *mdev, char *mdev_ch, u16 val)
 644 {
 645         struct most_channel *c = get_channel(mdev, mdev_ch);
 646 
 647         if (!c)
 648                 return -ENODEV;
 649         c->cfg.num_buffers = val;
 650         return 0;
 651 }
 652 
 653 int most_set_cfg_datatype(char *mdev, char *mdev_ch, char *buf)
 654 {
 655         int i;
 656         struct most_channel *c = get_channel(mdev, mdev_ch);
 657 
 658         if (!c)
 659                 return -ENODEV;
 660         for (i = 0; i < ARRAY_SIZE(ch_data_type); i++) {
 661                 if (!strcmp(buf, ch_data_type[i].name)) {
 662                         c->cfg.data_type = ch_data_type[i].most_ch_data_type;
 663                         break;
 664                 }
 665         }
 666 
 667         if (i == ARRAY_SIZE(ch_data_type))
 668                 pr_info("WARN: invalid attribute settings\n");
 669         return 0;
 670 }
 671 
 672 int most_set_cfg_direction(char *mdev, char *mdev_ch, char *buf)
 673 {
 674         struct most_channel *c = get_channel(mdev, mdev_ch);
 675 
 676         if (!c)
 677                 return -ENODEV;
 678         if (!strcmp(buf, "dir_rx\n")) {
 679                 c->cfg.direction = MOST_CH_RX;
 680         } else if (!strcmp(buf, "rx\n")) {
 681                 c->cfg.direction = MOST_CH_RX;
 682         } else if (!strcmp(buf, "dir_tx\n")) {
 683                 c->cfg.direction = MOST_CH_TX;
 684         } else if (!strcmp(buf, "tx\n")) {
 685                 c->cfg.direction = MOST_CH_TX;
 686         } else {
 687                 pr_info("Invalid direction\n");
 688                 return -ENODATA;
 689         }
 690         return 0;
 691 }
 692 
 693 int most_set_cfg_packets_xact(char *mdev, char *mdev_ch, u16 val)
 694 {
 695         struct most_channel *c = get_channel(mdev, mdev_ch);
 696 
 697         if (!c)
 698                 return -ENODEV;
 699         c->cfg.packets_per_xact = val;
 700         return 0;
 701 }
 702 
 703 int most_cfg_complete(char *comp_name)
 704 {
 705         struct core_component *comp;
 706 
 707         comp = match_component(comp_name);
 708         if (!comp)
 709                 return -ENODEV;
 710 
 711         return comp->cfg_complete();
 712 }
 713 
 714 int most_add_link(char *mdev, char *mdev_ch, char *comp_name, char *link_name,
 715                   char *comp_param)
 716 {
 717         struct most_channel *c = get_channel(mdev, mdev_ch);
 718         struct core_component *comp = match_component(comp_name);
 719 
 720         if (!c || !comp)
 721                 return -ENODEV;
 722 
 723         return link_channel_to_component(c, comp, link_name, comp_param);
 724 }
 725 
 726 /**
 727  * remove_link_store - store function for remove_link attribute
 728  * @drv: device driver
 729  * @buf: buffer
 730  * @len: buffer length
 731  *
 732  * Example:
 733  * echo "mdev0:ep81" >remove_link
 734  */
 735 static ssize_t remove_link_store(struct device_driver *drv,
 736                                  const char *buf,
 737                                  size_t len)
 738 {
 739         struct most_channel *c;
 740         struct core_component *comp;
 741         char buffer[STRING_SIZE];
 742         char *mdev;
 743         char *mdev_ch;
 744         char *comp_name;
 745         int ret;
 746         size_t max_len = min_t(size_t, len + 1, STRING_SIZE);
 747 
 748         strlcpy(buffer, buf, max_len);
 749         ret = split_string(buffer, &mdev, &mdev_ch, &comp_name, NULL);
 750         if (ret)
 751                 return ret;
 752         comp = match_component(comp_name);
 753         if (!comp)
 754                 return -ENODEV;
 755         c = get_channel(mdev, mdev_ch);
 756         if (!c)
 757                 return -ENODEV;
 758 
 759         if (comp->disconnect_channel(c->iface, c->channel_id))
 760                 return -EIO;
 761         if (c->pipe0.comp == comp)
 762                 c->pipe0.comp = NULL;
 763         if (c->pipe1.comp == comp)
 764                 c->pipe1.comp = NULL;
 765         return len;
 766 }
 767 
 768 int most_remove_link(char *mdev, char *mdev_ch, char *comp_name)
 769 {
 770         struct most_channel *c;
 771         struct core_component *comp;
 772 
 773         comp = match_component(comp_name);
 774         if (!comp)
 775                 return -ENODEV;
 776         c = get_channel(mdev, mdev_ch);
 777         if (!c)
 778                 return -ENODEV;
 779 
 780         if (comp->disconnect_channel(c->iface, c->channel_id))
 781                 return -EIO;
 782         if (c->pipe0.comp == comp)
 783                 c->pipe0.comp = NULL;
 784         if (c->pipe1.comp == comp)
 785                 c->pipe1.comp = NULL;
 786         return 0;
 787 }
 788 
 789 #define DRV_ATTR(_name)  (&driver_attr_##_name.attr)
 790 
 791 static DRIVER_ATTR_RO(links);
 792 static DRIVER_ATTR_RO(components);
 793 static DRIVER_ATTR_WO(remove_link);
 794 
 795 static struct attribute *mc_attrs[] = {
 796         DRV_ATTR(links),
 797         DRV_ATTR(components),
 798         DRV_ATTR(remove_link),
 799         NULL,
 800 };
 801 
 802 static struct attribute_group mc_attr_group = {
 803         .attrs = mc_attrs,
 804 };
 805 
 806 static const struct attribute_group *mc_attr_groups[] = {
 807         &mc_attr_group,
 808         NULL,
 809 };
 810 
 811 static int most_match(struct device *dev, struct device_driver *drv)
 812 {
 813         if (!strcmp(dev_name(dev), "most"))
 814                 return 0;
 815         else
 816                 return 1;
 817 }
 818 
 819 static inline void trash_mbo(struct mbo *mbo)
 820 {
 821         unsigned long flags;
 822         struct most_channel *c = mbo->context;
 823 
 824         spin_lock_irqsave(&c->fifo_lock, flags);
 825         list_add(&mbo->list, &c->trash_fifo);
 826         spin_unlock_irqrestore(&c->fifo_lock, flags);
 827 }
 828 
 829 static bool hdm_mbo_ready(struct most_channel *c)
 830 {
 831         bool empty;
 832 
 833         if (c->enqueue_halt)
 834                 return false;
 835 
 836         spin_lock_irq(&c->fifo_lock);
 837         empty = list_empty(&c->halt_fifo);
 838         spin_unlock_irq(&c->fifo_lock);
 839 
 840         return !empty;
 841 }
 842 
 843 static void nq_hdm_mbo(struct mbo *mbo)
 844 {
 845         unsigned long flags;
 846         struct most_channel *c = mbo->context;
 847 
 848         spin_lock_irqsave(&c->fifo_lock, flags);
 849         list_add_tail(&mbo->list, &c->halt_fifo);
 850         spin_unlock_irqrestore(&c->fifo_lock, flags);
 851         wake_up_interruptible(&c->hdm_fifo_wq);
 852 }
 853 
 854 static int hdm_enqueue_thread(void *data)
 855 {
 856         struct most_channel *c = data;
 857         struct mbo *mbo;
 858         int ret;
 859         typeof(c->iface->enqueue) enqueue = c->iface->enqueue;
 860 
 861         while (likely(!kthread_should_stop())) {
 862                 wait_event_interruptible(c->hdm_fifo_wq,
 863                                          hdm_mbo_ready(c) ||
 864                                          kthread_should_stop());
 865 
 866                 mutex_lock(&c->nq_mutex);
 867                 spin_lock_irq(&c->fifo_lock);
 868                 if (unlikely(c->enqueue_halt || list_empty(&c->halt_fifo))) {
 869                         spin_unlock_irq(&c->fifo_lock);
 870                         mutex_unlock(&c->nq_mutex);
 871                         continue;
 872                 }
 873 
 874                 mbo = list_pop_mbo(&c->halt_fifo);
 875                 spin_unlock_irq(&c->fifo_lock);
 876 
 877                 if (c->cfg.direction == MOST_CH_RX)
 878                         mbo->buffer_length = c->cfg.buffer_size;
 879 
 880                 ret = enqueue(mbo->ifp, mbo->hdm_channel_id, mbo);
 881                 mutex_unlock(&c->nq_mutex);
 882 
 883                 if (unlikely(ret)) {
 884                         pr_err("hdm enqueue failed\n");
 885                         nq_hdm_mbo(mbo);
 886                         c->hdm_enqueue_task = NULL;
 887                         return 0;
 888                 }
 889         }
 890 
 891         return 0;
 892 }
 893 
 894 static int run_enqueue_thread(struct most_channel *c, int channel_id)
 895 {
 896         struct task_struct *task =
 897                 kthread_run(hdm_enqueue_thread, c, "hdm_fifo_%d",
 898                             channel_id);
 899 
 900         if (IS_ERR(task))
 901                 return PTR_ERR(task);
 902 
 903         c->hdm_enqueue_task = task;
 904         return 0;
 905 }
 906 
 907 /**
 908  * arm_mbo - recycle MBO for further usage
 909  * @mbo: most buffer
 910  *
 911  * This puts an MBO back to the list to have it ready for up coming
 912  * tx transactions.
 913  *
 914  * In case the MBO belongs to a channel that recently has been
 915  * poisoned, the MBO is scheduled to be trashed.
 916  * Calls the completion handler of an attached component.
 917  */
 918 static void arm_mbo(struct mbo *mbo)
 919 {
 920         unsigned long flags;
 921         struct most_channel *c;
 922 
 923         c = mbo->context;
 924 
 925         if (c->is_poisoned) {
 926                 trash_mbo(mbo);
 927                 return;
 928         }
 929 
 930         spin_lock_irqsave(&c->fifo_lock, flags);
 931         ++*mbo->num_buffers_ptr;
 932         list_add_tail(&mbo->list, &c->fifo);
 933         spin_unlock_irqrestore(&c->fifo_lock, flags);
 934 
 935         if (c->pipe0.refs && c->pipe0.comp->tx_completion)
 936                 c->pipe0.comp->tx_completion(c->iface, c->channel_id);
 937 
 938         if (c->pipe1.refs && c->pipe1.comp->tx_completion)
 939                 c->pipe1.comp->tx_completion(c->iface, c->channel_id);
 940 }
 941 
 942 /**
 943  * arm_mbo_chain - helper function that arms an MBO chain for the HDM
 944  * @c: pointer to interface channel
 945  * @dir: direction of the channel
 946  * @compl: pointer to completion function
 947  *
 948  * This allocates buffer objects including the containing DMA coherent
 949  * buffer and puts them in the fifo.
 950  * Buffers of Rx channels are put in the kthread fifo, hence immediately
 951  * submitted to the HDM.
 952  *
 953  * Returns the number of allocated and enqueued MBOs.
 954  */
 955 static int arm_mbo_chain(struct most_channel *c, int dir,
 956                          void (*compl)(struct mbo *))
 957 {
 958         unsigned int i;
 959         struct mbo *mbo;
 960         unsigned long flags;
 961         u32 coherent_buf_size = c->cfg.buffer_size + c->cfg.extra_len;
 962 
 963         atomic_set(&c->mbo_nq_level, 0);
 964 
 965         for (i = 0; i < c->cfg.num_buffers; i++) {
 966                 mbo = kzalloc(sizeof(*mbo), GFP_KERNEL);
 967                 if (!mbo)
 968                         goto flush_fifos;
 969 
 970                 mbo->context = c;
 971                 mbo->ifp = c->iface;
 972                 mbo->hdm_channel_id = c->channel_id;
 973                 if (c->iface->dma_alloc) {
 974                         mbo->virt_address =
 975                                 c->iface->dma_alloc(mbo, coherent_buf_size);
 976                 } else {
 977                         mbo->virt_address =
 978                                 kzalloc(coherent_buf_size, GFP_KERNEL);
 979                 }
 980                 if (!mbo->virt_address)
 981                         goto release_mbo;
 982 
 983                 mbo->complete = compl;
 984                 mbo->num_buffers_ptr = &dummy_num_buffers;
 985                 if (dir == MOST_CH_RX) {
 986                         nq_hdm_mbo(mbo);
 987                         atomic_inc(&c->mbo_nq_level);
 988                 } else {
 989                         spin_lock_irqsave(&c->fifo_lock, flags);
 990                         list_add_tail(&mbo->list, &c->fifo);
 991                         spin_unlock_irqrestore(&c->fifo_lock, flags);
 992                 }
 993         }
 994         return c->cfg.num_buffers;
 995 
 996 release_mbo:
 997         kfree(mbo);
 998 
 999 flush_fifos:
1000         flush_channel_fifos(c);
1001         return 0;
1002 }
1003 
1004 /**
1005  * most_submit_mbo - submits an MBO to fifo
1006  * @mbo: most buffer
1007  */
1008 void most_submit_mbo(struct mbo *mbo)
1009 {
1010         if (WARN_ONCE(!mbo || !mbo->context,
1011                       "bad mbo or missing channel reference\n"))
1012                 return;
1013 
1014         nq_hdm_mbo(mbo);
1015 }
1016 EXPORT_SYMBOL_GPL(most_submit_mbo);
1017 
1018 /**
1019  * most_write_completion - write completion handler
1020  * @mbo: most buffer
1021  *
1022  * This recycles the MBO for further usage. In case the channel has been
1023  * poisoned, the MBO is scheduled to be trashed.
1024  */
1025 static void most_write_completion(struct mbo *mbo)
1026 {
1027         struct most_channel *c;
1028 
1029         c = mbo->context;
1030         if (mbo->status == MBO_E_INVAL)
1031                 pr_info("WARN: Tx MBO status: invalid\n");
1032         if (unlikely(c->is_poisoned || (mbo->status == MBO_E_CLOSE)))
1033                 trash_mbo(mbo);
1034         else
1035                 arm_mbo(mbo);
1036 }
1037 
1038 int channel_has_mbo(struct most_interface *iface, int id,
1039                     struct core_component *comp)
1040 {
1041         struct most_channel *c = iface->p->channel[id];
1042         unsigned long flags;
1043         int empty;
1044 
1045         if (unlikely(!c))
1046                 return -EINVAL;
1047 
1048         if (c->pipe0.refs && c->pipe1.refs &&
1049             ((comp == c->pipe0.comp && c->pipe0.num_buffers <= 0) ||
1050              (comp == c->pipe1.comp && c->pipe1.num_buffers <= 0)))
1051                 return 0;
1052 
1053         spin_lock_irqsave(&c->fifo_lock, flags);
1054         empty = list_empty(&c->fifo);
1055         spin_unlock_irqrestore(&c->fifo_lock, flags);
1056         return !empty;
1057 }
1058 EXPORT_SYMBOL_GPL(channel_has_mbo);
1059 
1060 /**
1061  * most_get_mbo - get pointer to an MBO of pool
1062  * @iface: pointer to interface instance
1063  * @id: channel ID
1064  * @comp: driver component
1065  *
1066  * This attempts to get a free buffer out of the channel fifo.
1067  * Returns a pointer to MBO on success or NULL otherwise.
1068  */
1069 struct mbo *most_get_mbo(struct most_interface *iface, int id,
1070                          struct core_component *comp)
1071 {
1072         struct mbo *mbo;
1073         struct most_channel *c;
1074         unsigned long flags;
1075         int *num_buffers_ptr;
1076 
1077         c = iface->p->channel[id];
1078         if (unlikely(!c))
1079                 return NULL;
1080 
1081         if (c->pipe0.refs && c->pipe1.refs &&
1082             ((comp == c->pipe0.comp && c->pipe0.num_buffers <= 0) ||
1083              (comp == c->pipe1.comp && c->pipe1.num_buffers <= 0)))
1084                 return NULL;
1085 
1086         if (comp == c->pipe0.comp)
1087                 num_buffers_ptr = &c->pipe0.num_buffers;
1088         else if (comp == c->pipe1.comp)
1089                 num_buffers_ptr = &c->pipe1.num_buffers;
1090         else
1091                 num_buffers_ptr = &dummy_num_buffers;
1092 
1093         spin_lock_irqsave(&c->fifo_lock, flags);
1094         if (list_empty(&c->fifo)) {
1095                 spin_unlock_irqrestore(&c->fifo_lock, flags);
1096                 return NULL;
1097         }
1098         mbo = list_pop_mbo(&c->fifo);
1099         --*num_buffers_ptr;
1100         spin_unlock_irqrestore(&c->fifo_lock, flags);
1101 
1102         mbo->num_buffers_ptr = num_buffers_ptr;
1103         mbo->buffer_length = c->cfg.buffer_size;
1104         return mbo;
1105 }
1106 EXPORT_SYMBOL_GPL(most_get_mbo);
1107 
1108 /**
1109  * most_put_mbo - return buffer to pool
1110  * @mbo: most buffer
1111  */
1112 void most_put_mbo(struct mbo *mbo)
1113 {
1114         struct most_channel *c = mbo->context;
1115 
1116         if (c->cfg.direction == MOST_CH_TX) {
1117                 arm_mbo(mbo);
1118                 return;
1119         }
1120         nq_hdm_mbo(mbo);
1121         atomic_inc(&c->mbo_nq_level);
1122 }
1123 EXPORT_SYMBOL_GPL(most_put_mbo);
1124 
1125 /**
1126  * most_read_completion - read completion handler
1127  * @mbo: most buffer
1128  *
1129  * This function is called by the HDM when data has been received from the
1130  * hardware and copied to the buffer of the MBO.
1131  *
1132  * In case the channel has been poisoned it puts the buffer in the trash queue.
1133  * Otherwise, it passes the buffer to an component for further processing.
1134  */
1135 static void most_read_completion(struct mbo *mbo)
1136 {
1137         struct most_channel *c = mbo->context;
1138 
1139         if (unlikely(c->is_poisoned || (mbo->status == MBO_E_CLOSE))) {
1140                 trash_mbo(mbo);
1141                 return;
1142         }
1143 
1144         if (mbo->status == MBO_E_INVAL) {
1145                 nq_hdm_mbo(mbo);
1146                 atomic_inc(&c->mbo_nq_level);
1147                 return;
1148         }
1149 
1150         if (atomic_sub_and_test(1, &c->mbo_nq_level))
1151                 c->is_starving = 1;
1152 
1153         if (c->pipe0.refs && c->pipe0.comp->rx_completion &&
1154             c->pipe0.comp->rx_completion(mbo) == 0)
1155                 return;
1156 
1157         if (c->pipe1.refs && c->pipe1.comp->rx_completion &&
1158             c->pipe1.comp->rx_completion(mbo) == 0)
1159                 return;
1160 
1161         most_put_mbo(mbo);
1162 }
1163 
1164 /**
1165  * most_start_channel - prepares a channel for communication
1166  * @iface: pointer to interface instance
1167  * @id: channel ID
1168  * @comp: driver component
1169  *
1170  * This prepares the channel for usage. Cross-checks whether the
1171  * channel's been properly configured.
1172  *
1173  * Returns 0 on success or error code otherwise.
1174  */
1175 int most_start_channel(struct most_interface *iface, int id,
1176                        struct core_component *comp)
1177 {
1178         int num_buffer;
1179         int ret;
1180         struct most_channel *c = iface->p->channel[id];
1181 
1182         if (unlikely(!c))
1183                 return -EINVAL;
1184 
1185         mutex_lock(&c->start_mutex);
1186         if (c->pipe0.refs + c->pipe1.refs > 0)
1187                 goto out; /* already started by another component */
1188 
1189         if (!try_module_get(iface->mod)) {
1190                 pr_info("failed to acquire HDM lock\n");
1191                 mutex_unlock(&c->start_mutex);
1192                 return -ENOLCK;
1193         }
1194 
1195         c->cfg.extra_len = 0;
1196         if (c->iface->configure(c->iface, c->channel_id, &c->cfg)) {
1197                 pr_info("channel configuration failed. Go check settings...\n");
1198                 ret = -EINVAL;
1199                 goto err_put_module;
1200         }
1201 
1202         init_waitqueue_head(&c->hdm_fifo_wq);
1203 
1204         if (c->cfg.direction == MOST_CH_RX)
1205                 num_buffer = arm_mbo_chain(c, c->cfg.direction,
1206                                            most_read_completion);
1207         else
1208                 num_buffer = arm_mbo_chain(c, c->cfg.direction,
1209                                            most_write_completion);
1210         if (unlikely(!num_buffer)) {
1211                 ret = -ENOMEM;
1212                 goto err_put_module;
1213         }
1214 
1215         ret = run_enqueue_thread(c, id);
1216         if (ret)
1217                 goto err_put_module;
1218 
1219         c->is_starving = 0;
1220         c->pipe0.num_buffers = c->cfg.num_buffers / 2;
1221         c->pipe1.num_buffers = c->cfg.num_buffers - c->pipe0.num_buffers;
1222         atomic_set(&c->mbo_ref, num_buffer);
1223 
1224 out:
1225         if (comp == c->pipe0.comp)
1226                 c->pipe0.refs++;
1227         if (comp == c->pipe1.comp)
1228                 c->pipe1.refs++;
1229         mutex_unlock(&c->start_mutex);
1230         return 0;
1231 
1232 err_put_module:
1233         module_put(iface->mod);
1234         mutex_unlock(&c->start_mutex);
1235         return ret;
1236 }
1237 EXPORT_SYMBOL_GPL(most_start_channel);
1238 
1239 /**
1240  * most_stop_channel - stops a running channel
1241  * @iface: pointer to interface instance
1242  * @id: channel ID
1243  * @comp: driver component
1244  */
1245 int most_stop_channel(struct most_interface *iface, int id,
1246                       struct core_component *comp)
1247 {
1248         struct most_channel *c;
1249 
1250         if (unlikely((!iface) || (id >= iface->num_channels) || (id < 0))) {
1251                 pr_err("Bad interface or index out of range\n");
1252                 return -EINVAL;
1253         }
1254         c = iface->p->channel[id];
1255         if (unlikely(!c))
1256                 return -EINVAL;
1257 
1258         mutex_lock(&c->start_mutex);
1259         if (c->pipe0.refs + c->pipe1.refs >= 2)
1260                 goto out;
1261 
1262         if (c->hdm_enqueue_task)
1263                 kthread_stop(c->hdm_enqueue_task);
1264         c->hdm_enqueue_task = NULL;
1265 
1266         if (iface->mod)
1267                 module_put(iface->mod);
1268 
1269         c->is_poisoned = true;
1270         if (c->iface->poison_channel(c->iface, c->channel_id)) {
1271                 pr_err("Cannot stop channel %d of mdev %s\n", c->channel_id,
1272                        c->iface->description);
1273                 mutex_unlock(&c->start_mutex);
1274                 return -EAGAIN;
1275         }
1276         flush_trash_fifo(c);
1277         flush_channel_fifos(c);
1278 
1279 #ifdef CMPL_INTERRUPTIBLE
1280         if (wait_for_completion_interruptible(&c->cleanup)) {
1281                 pr_info("Interrupted while clean up ch %d\n", c->channel_id);
1282                 mutex_unlock(&c->start_mutex);
1283                 return -EINTR;
1284         }
1285 #else
1286         wait_for_completion(&c->cleanup);
1287 #endif
1288         c->is_poisoned = false;
1289 
1290 out:
1291         if (comp == c->pipe0.comp)
1292                 c->pipe0.refs--;
1293         if (comp == c->pipe1.comp)
1294                 c->pipe1.refs--;
1295         mutex_unlock(&c->start_mutex);
1296         return 0;
1297 }
1298 EXPORT_SYMBOL_GPL(most_stop_channel);
1299 
1300 /**
1301  * most_register_component - registers a driver component with the core
1302  * @comp: driver component
1303  */
1304 int most_register_component(struct core_component *comp)
1305 {
1306         if (!comp) {
1307                 pr_err("Bad component\n");
1308                 return -EINVAL;
1309         }
1310         list_add_tail(&comp->list, &mc.comp_list);
1311         pr_info("registered new core component %s\n", comp->name);
1312         return 0;
1313 }
1314 EXPORT_SYMBOL_GPL(most_register_component);
1315 
1316 static int disconnect_channels(struct device *dev, void *data)
1317 {
1318         struct most_interface *iface;
1319         struct most_channel *c, *tmp;
1320         struct core_component *comp = data;
1321 
1322         iface = to_most_interface(dev);
1323         list_for_each_entry_safe(c, tmp, &iface->p->channel_list, list) {
1324                 if (c->pipe0.comp == comp || c->pipe1.comp == comp)
1325                         comp->disconnect_channel(c->iface, c->channel_id);
1326                 if (c->pipe0.comp == comp)
1327                         c->pipe0.comp = NULL;
1328                 if (c->pipe1.comp == comp)
1329                         c->pipe1.comp = NULL;
1330         }
1331         return 0;
1332 }
1333 
1334 /**
1335  * most_deregister_component - deregisters a driver component with the core
1336  * @comp: driver component
1337  */
1338 int most_deregister_component(struct core_component *comp)
1339 {
1340         if (!comp) {
1341                 pr_err("Bad component\n");
1342                 return -EINVAL;
1343         }
1344 
1345         bus_for_each_dev(&mc.bus, NULL, comp, disconnect_channels);
1346         list_del(&comp->list);
1347         pr_info("deregistering component %s\n", comp->name);
1348         return 0;
1349 }
1350 EXPORT_SYMBOL_GPL(most_deregister_component);
1351 
1352 static void release_interface(struct device *dev)
1353 {
1354         pr_info("releasing interface dev %s...\n", dev_name(dev));
1355 }
1356 
1357 static void release_channel(struct device *dev)
1358 {
1359         pr_info("releasing channel dev %s...\n", dev_name(dev));
1360 }
1361 
1362 /**
1363  * most_register_interface - registers an interface with core
1364  * @iface: device interface
1365  *
1366  * Allocates and initializes a new interface instance and all of its channels.
1367  * Returns a pointer to kobject or an error pointer.
1368  */
1369 int most_register_interface(struct most_interface *iface)
1370 {
1371         unsigned int i;
1372         int id;
1373         struct most_channel *c;
1374 
1375         if (!iface || !iface->enqueue || !iface->configure ||
1376             !iface->poison_channel || (iface->num_channels > MAX_CHANNELS)) {
1377                 pr_err("Bad interface or channel overflow\n");
1378                 return -EINVAL;
1379         }
1380 
1381         id = ida_simple_get(&mdev_id, 0, 0, GFP_KERNEL);
1382         if (id < 0) {
1383                 pr_info("Failed to alloc mdev ID\n");
1384                 return id;
1385         }
1386 
1387         iface->p = kzalloc(sizeof(*iface->p), GFP_KERNEL);
1388         if (!iface->p) {
1389                 ida_simple_remove(&mdev_id, id);
1390                 return -ENOMEM;
1391         }
1392 
1393         INIT_LIST_HEAD(&iface->p->channel_list);
1394         iface->p->dev_id = id;
1395         strscpy(iface->p->name, iface->description, sizeof(iface->p->name));
1396         iface->dev.init_name = iface->p->name;
1397         iface->dev.bus = &mc.bus;
1398         iface->dev.parent = &mc.dev;
1399         iface->dev.groups = interface_attr_groups;
1400         iface->dev.release = release_interface;
1401         if (device_register(&iface->dev)) {
1402                 pr_err("registering iface->dev failed\n");
1403                 kfree(iface->p);
1404                 ida_simple_remove(&mdev_id, id);
1405                 return -ENOMEM;
1406         }
1407 
1408         for (i = 0; i < iface->num_channels; i++) {
1409                 const char *name_suffix = iface->channel_vector[i].name_suffix;
1410 
1411                 c = kzalloc(sizeof(*c), GFP_KERNEL);
1412                 if (!c)
1413                         goto err_free_resources;
1414                 if (!name_suffix)
1415                         snprintf(c->name, STRING_SIZE, "ch%d", i);
1416                 else
1417                         snprintf(c->name, STRING_SIZE, "%s", name_suffix);
1418                 c->dev.init_name = c->name;
1419                 c->dev.parent = &iface->dev;
1420                 c->dev.groups = channel_attr_groups;
1421                 c->dev.release = release_channel;
1422                 iface->p->channel[i] = c;
1423                 c->is_starving = 0;
1424                 c->iface = iface;
1425                 c->channel_id = i;
1426                 c->keep_mbo = false;
1427                 c->enqueue_halt = false;
1428                 c->is_poisoned = false;
1429                 c->cfg.direction = 0;
1430                 c->cfg.data_type = 0;
1431                 c->cfg.num_buffers = 0;
1432                 c->cfg.buffer_size = 0;
1433                 c->cfg.subbuffer_size = 0;
1434                 c->cfg.packets_per_xact = 0;
1435                 spin_lock_init(&c->fifo_lock);
1436                 INIT_LIST_HEAD(&c->fifo);
1437                 INIT_LIST_HEAD(&c->trash_fifo);
1438                 INIT_LIST_HEAD(&c->halt_fifo);
1439                 init_completion(&c->cleanup);
1440                 atomic_set(&c->mbo_ref, 0);
1441                 mutex_init(&c->start_mutex);
1442                 mutex_init(&c->nq_mutex);
1443                 list_add_tail(&c->list, &iface->p->channel_list);
1444                 if (device_register(&c->dev)) {
1445                         pr_err("registering c->dev failed\n");
1446                         goto err_free_most_channel;
1447                 }
1448         }
1449         pr_info("registered new device mdev%d (%s)\n",
1450                 id, iface->description);
1451         most_interface_register_notify(iface->description);
1452         return 0;
1453 
1454 err_free_most_channel:
1455         kfree(c);
1456 
1457 err_free_resources:
1458         while (i > 0) {
1459                 c = iface->p->channel[--i];
1460                 device_unregister(&c->dev);
1461                 kfree(c);
1462         }
1463         kfree(iface->p);
1464         device_unregister(&iface->dev);
1465         ida_simple_remove(&mdev_id, id);
1466         return -ENOMEM;
1467 }
1468 EXPORT_SYMBOL_GPL(most_register_interface);
1469 
1470 /**
1471  * most_deregister_interface - deregisters an interface with core
1472  * @iface: device interface
1473  *
1474  * Before removing an interface instance from the list, all running
1475  * channels are stopped and poisoned.
1476  */
1477 void most_deregister_interface(struct most_interface *iface)
1478 {
1479         int i;
1480         struct most_channel *c;
1481 
1482         pr_info("deregistering device %s (%s)\n", dev_name(&iface->dev),
1483                 iface->description);
1484         for (i = 0; i < iface->num_channels; i++) {
1485                 c = iface->p->channel[i];
1486                 if (c->pipe0.comp)
1487                         c->pipe0.comp->disconnect_channel(c->iface,
1488                                                         c->channel_id);
1489                 if (c->pipe1.comp)
1490                         c->pipe1.comp->disconnect_channel(c->iface,
1491                                                         c->channel_id);
1492                 c->pipe0.comp = NULL;
1493                 c->pipe1.comp = NULL;
1494                 list_del(&c->list);
1495                 device_unregister(&c->dev);
1496                 kfree(c);
1497         }
1498 
1499         ida_simple_remove(&mdev_id, iface->p->dev_id);
1500         kfree(iface->p);
1501         device_unregister(&iface->dev);
1502 }
1503 EXPORT_SYMBOL_GPL(most_deregister_interface);
1504 
1505 /**
1506  * most_stop_enqueue - prevents core from enqueueing MBOs
1507  * @iface: pointer to interface
1508  * @id: channel id
1509  *
1510  * This is called by an HDM that _cannot_ attend to its duties and
1511  * is imminent to get run over by the core. The core is not going to
1512  * enqueue any further packets unless the flagging HDM calls
1513  * most_resume enqueue().
1514  */
1515 void most_stop_enqueue(struct most_interface *iface, int id)
1516 {
1517         struct most_channel *c = iface->p->channel[id];
1518 
1519         if (!c)
1520                 return;
1521 
1522         mutex_lock(&c->nq_mutex);
1523         c->enqueue_halt = true;
1524         mutex_unlock(&c->nq_mutex);
1525 }
1526 EXPORT_SYMBOL_GPL(most_stop_enqueue);
1527 
1528 /**
1529  * most_resume_enqueue - allow core to enqueue MBOs again
1530  * @iface: pointer to interface
1531  * @id: channel id
1532  *
1533  * This clears the enqueue halt flag and enqueues all MBOs currently
1534  * sitting in the wait fifo.
1535  */
1536 void most_resume_enqueue(struct most_interface *iface, int id)
1537 {
1538         struct most_channel *c = iface->p->channel[id];
1539 
1540         if (!c)
1541                 return;
1542 
1543         mutex_lock(&c->nq_mutex);
1544         c->enqueue_halt = false;
1545         mutex_unlock(&c->nq_mutex);
1546 
1547         wake_up_interruptible(&c->hdm_fifo_wq);
1548 }
1549 EXPORT_SYMBOL_GPL(most_resume_enqueue);
1550 
1551 static void release_most_sub(struct device *dev)
1552 {
1553         pr_info("releasing most_subsystem\n");
1554 }
1555 
1556 static int __init most_init(void)
1557 {
1558         int err;
1559 
1560         pr_info("init()\n");
1561         INIT_LIST_HEAD(&mc.comp_list);
1562         ida_init(&mdev_id);
1563 
1564         mc.bus.name = "most",
1565         mc.bus.match = most_match,
1566         mc.drv.name = "most_core",
1567         mc.drv.bus = &mc.bus,
1568         mc.drv.groups = mc_attr_groups;
1569 
1570         err = bus_register(&mc.bus);
1571         if (err) {
1572                 pr_info("Cannot register most bus\n");
1573                 return err;
1574         }
1575         err = driver_register(&mc.drv);
1576         if (err) {
1577                 pr_info("Cannot register core driver\n");
1578                 goto err_unregister_bus;
1579         }
1580         mc.dev.init_name = "most_bus";
1581         mc.dev.release = release_most_sub;
1582         if (device_register(&mc.dev)) {
1583                 err = -ENOMEM;
1584                 goto err_unregister_driver;
1585         }
1586         configfs_init();
1587         return 0;
1588 
1589 err_unregister_driver:
1590         driver_unregister(&mc.drv);
1591 err_unregister_bus:
1592         bus_unregister(&mc.bus);
1593         return err;
1594 }
1595 
1596 static void __exit most_exit(void)
1597 {
1598         pr_info("exit core module\n");
1599         device_unregister(&mc.dev);
1600         driver_unregister(&mc.drv);
1601         bus_unregister(&mc.bus);
1602         ida_destroy(&mdev_id);
1603 }
1604 
1605 module_init(most_init);
1606 module_exit(most_exit);
1607 MODULE_LICENSE("GPL");
1608 MODULE_AUTHOR("Christian Gromm <christian.gromm@microchip.com>");
1609 MODULE_DESCRIPTION("Core module of stacked MOST Linux driver");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/staging/most/core.c

DEFINITIONS
