drivers/thunderbolt/ctl.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Thunderbolt Cactus Ridge driver - control channel and configuration commands
   4  *
   5  * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
   6  */
   7
   8 #include <linux/crc32.h>
   9 #include <linux/delay.h>
  10 #include <linux/slab.h>
  11 #include <linux/pci.h>
  12 #include <linux/dmapool.h>
  13 #include <linux/workqueue.h>
  14
  15 #include "ctl.h"
  16
  17
  18 #define TB_CTL_RX_PKG_COUNT     10
  19 #define TB_CTL_RETRIES          4
  20
  21 /**
  22  * struct tb_cfg - thunderbolt control channel
  23  */
  24 struct tb_ctl {
  25         struct tb_nhi *nhi;
  26         struct tb_ring *tx;
  27         struct tb_ring *rx;
  28
  29         struct dma_pool *frame_pool;
  30         struct ctl_pkg *rx_packets[TB_CTL_RX_PKG_COUNT];
  31         struct mutex request_queue_lock;
  32         struct list_head request_queue;
  33         bool running;
  34
  35         event_cb callback;
  36         void *callback_data;
  37 };
  38
  39
  40 #define tb_ctl_WARN(ctl, format, arg...) \
  41         dev_WARN(&(ctl)->nhi->pdev->dev, format, ## arg)
  42
  43 #define tb_ctl_err(ctl, format, arg...) \
  44         dev_err(&(ctl)->nhi->pdev->dev, format, ## arg)
  45
  46 #define tb_ctl_warn(ctl, format, arg...) \
  47         dev_warn(&(ctl)->nhi->pdev->dev, format, ## arg)
  48
  49 #define tb_ctl_info(ctl, format, arg...) \
  50         dev_info(&(ctl)->nhi->pdev->dev, format, ## arg)
  51
  52 #define tb_ctl_dbg(ctl, format, arg...) \
  53         dev_dbg(&(ctl)->nhi->pdev->dev, format, ## arg)
  54
  55 static DECLARE_WAIT_QUEUE_HEAD(tb_cfg_request_cancel_queue);
  56 /* Serializes access to request kref_get/put */
  57 static DEFINE_MUTEX(tb_cfg_request_lock);
  58
  59 /**
  60  * tb_cfg_request_alloc() - Allocates a new config request
  61  *
  62  * This is refcounted object so when you are done with this, call
  63  * tb_cfg_request_put() to it.
  64  */
  65 struct tb_cfg_request *tb_cfg_request_alloc(void)
  66 {
  67         struct tb_cfg_request *req;
  68
  69         req = kzalloc(sizeof(*req), GFP_KERNEL);
  70         if (!req)
  71                 return NULL;
  72
  73         kref_init(&req->kref);
  74
  75         return req;
  76 }
  77
  78 /**
  79  * tb_cfg_request_get() - Increase refcount of a request
  80  * @req: Request whose refcount is increased
  81  */
  82 void tb_cfg_request_get(struct tb_cfg_request *req)
  83 {
  84         mutex_lock(&tb_cfg_request_lock);
  85         kref_get(&req->kref);
  86         mutex_unlock(&tb_cfg_request_lock);
  87 }
  88
  89 static void tb_cfg_request_destroy(struct kref *kref)
  90 {
  91         struct tb_cfg_request *req = container_of(kref, typeof(*req), kref);
  92
  93         kfree(req);
  94 }
  95
  96 /**
  97  * tb_cfg_request_put() - Decrease refcount and possibly release the request
  98  * @req: Request whose refcount is decreased
  99  *
 100  * Call this function when you are done with the request. When refcount
 101  * goes to %0 the object is released.
 102  */
 103 void tb_cfg_request_put(struct tb_cfg_request *req)
 104 {
 105         mutex_lock(&tb_cfg_request_lock);
 106         kref_put(&req->kref, tb_cfg_request_destroy);
 107         mutex_unlock(&tb_cfg_request_lock);
 108 }
 109
 110 static int tb_cfg_request_enqueue(struct tb_ctl *ctl,
 111                                   struct tb_cfg_request *req)
 112 {
 113         WARN_ON(test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags));
 114         WARN_ON(req->ctl);
 115
 116         mutex_lock(&ctl->request_queue_lock);
 117         if (!ctl->running) {
 118                 mutex_unlock(&ctl->request_queue_lock);
 119                 return -ENOTCONN;
 120         }
 121         req->ctl = ctl;
 122         list_add_tail(&req->list, &ctl->request_queue);
 123         set_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
 124         mutex_unlock(&ctl->request_queue_lock);
 125         return 0;
 126 }
 127
 128 static void tb_cfg_request_dequeue(struct tb_cfg_request *req)
 129 {
 130         struct tb_ctl *ctl = req->ctl;
 131
 132         mutex_lock(&ctl->request_queue_lock);
 133         list_del(&req->list);
 134         clear_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
 135         if (test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
 136                 wake_up(&tb_cfg_request_cancel_queue);
 137         mutex_unlock(&ctl->request_queue_lock);
 138 }
 139
 140 static bool tb_cfg_request_is_active(struct tb_cfg_request *req)
 141 {
 142         return test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
 143 }
 144
 145 static struct tb_cfg_request *
 146 tb_cfg_request_find(struct tb_ctl *ctl, struct ctl_pkg *pkg)
 147 {
 148         struct tb_cfg_request *req;
 149         bool found = false;
 150
 151         mutex_lock(&pkg->ctl->request_queue_lock);
 152         list_for_each_entry(req, &pkg->ctl->request_queue, list) {
 153                 tb_cfg_request_get(req);
 154                 if (req->match(req, pkg)) {
 155                         found = true;
 156                         break;
 157                 }
 158                 tb_cfg_request_put(req);
 159         }
 160         mutex_unlock(&pkg->ctl->request_queue_lock);
 161
 162         return found ? req : NULL;
 163 }
 164
 165 /* utility functions */
 166
 167
 168 static int check_header(const struct ctl_pkg *pkg, u32 len,
 169                         enum tb_cfg_pkg_type type, u64 route)
 170 {
 171         struct tb_cfg_header *header = pkg->buffer;
 172
 173         /* check frame, TODO: frame flags */
 174         if (WARN(len != pkg->frame.size,
 175                         "wrong framesize (expected %#x, got %#x)\n",
 176                         len, pkg->frame.size))
 177                 return -EIO;
 178         if (WARN(type != pkg->frame.eof, "wrong eof (expected %#x, got %#x)\n",
 179                         type, pkg->frame.eof))
 180                 return -EIO;
 181         if (WARN(pkg->frame.sof, "wrong sof (expected 0x0, got %#x)\n",
 182                         pkg->frame.sof))
 183                 return -EIO;
 184
 185         /* check header */
 186         if (WARN(header->unknown != 1 << 9,
 187                         "header->unknown is %#x\n", header->unknown))
 188                 return -EIO;
 189         if (WARN(route != tb_cfg_get_route(header),
 190                         "wrong route (expected %llx, got %llx)",
 191                         route, tb_cfg_get_route(header)))
 192                 return -EIO;
 193         return 0;
 194 }
 195
 196 static int check_config_address(struct tb_cfg_address addr,
 197                                 enum tb_cfg_space space, u32 offset,
 198                                 u32 length)
 199 {
 200         if (WARN(addr.zero, "addr.zero is %#x\n", addr.zero))
 201                 return -EIO;
 202         if (WARN(space != addr.space, "wrong space (expected %x, got %x\n)",
 203                         space, addr.space))
 204                 return -EIO;
 205         if (WARN(offset != addr.offset, "wrong offset (expected %x, got %x\n)",
 206                         offset, addr.offset))
 207                 return -EIO;
 208         if (WARN(length != addr.length, "wrong space (expected %x, got %x\n)",
 209                         length, addr.length))
 210                 return -EIO;
 211         /*
 212          * We cannot check addr->port as it is set to the upstream port of the
 213          * sender.
 214          */
 215         return 0;
 216 }
 217
 218 static struct tb_cfg_result decode_error(const struct ctl_pkg *response)
 219 {
 220         struct cfg_error_pkg *pkg = response->buffer;
 221         struct tb_cfg_result res = { 0 };
 222         res.response_route = tb_cfg_get_route(&pkg->header);
 223         res.response_port = 0;
 224         res.err = check_header(response, sizeof(*pkg), TB_CFG_PKG_ERROR,
 225                                tb_cfg_get_route(&pkg->header));
 226         if (res.err)
 227                 return res;
 228
 229         WARN(pkg->zero1, "pkg->zero1 is %#x\n", pkg->zero1);
 230         WARN(pkg->zero2, "pkg->zero1 is %#x\n", pkg->zero1);
 231         WARN(pkg->zero3, "pkg->zero1 is %#x\n", pkg->zero1);
 232         res.err = 1;
 233         res.tb_error = pkg->error;
 234         res.response_port = pkg->port;
 235         return res;
 236
 237 }
 238
 239 static struct tb_cfg_result parse_header(const struct ctl_pkg *pkg, u32 len,
 240                                          enum tb_cfg_pkg_type type, u64 route)
 241 {
 242         struct tb_cfg_header *header = pkg->buffer;
 243         struct tb_cfg_result res = { 0 };
 244
 245         if (pkg->frame.eof == TB_CFG_PKG_ERROR)
 246                 return decode_error(pkg);
 247
 248         res.response_port = 0; /* will be updated later for cfg_read/write */
 249         res.response_route = tb_cfg_get_route(header);
 250         res.err = check_header(pkg, len, type, route);
 251         return res;
 252 }
 253
 254 static void tb_cfg_print_error(struct tb_ctl *ctl,
 255                                const struct tb_cfg_result *res)
 256 {
 257         WARN_ON(res->err != 1);
 258         switch (res->tb_error) {
 259         case TB_CFG_ERROR_PORT_NOT_CONNECTED:
 260                 /* Port is not connected. This can happen during surprise
 261                  * removal. Do not warn. */
 262                 return;
 263         case TB_CFG_ERROR_INVALID_CONFIG_SPACE:
 264                 /*
 265                  * Invalid cfg_space/offset/length combination in
 266                  * cfg_read/cfg_write.
 267                  */
 268                 tb_ctl_WARN(ctl,
 269                         "CFG_ERROR(%llx:%x): Invalid config space or offset\n",
 270                         res->response_route, res->response_port);
 271                 return;
 272         case TB_CFG_ERROR_NO_SUCH_PORT:
 273                 /*
 274                  * - The route contains a non-existent port.
 275                  * - The route contains a non-PHY port (e.g. PCIe).
 276                  * - The port in cfg_read/cfg_write does not exist.
 277                  */
 278                 tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Invalid port\n",
 279                         res->response_route, res->response_port);
 280                 return;
 281         case TB_CFG_ERROR_LOOP:
 282                 tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Route contains a loop\n",
 283                         res->response_route, res->response_port);
 284                 return;
 285         default:
 286                 /* 5,6,7,9 and 11 are also valid error codes */
 287                 tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Unknown error\n",
 288                         res->response_route, res->response_port);
 289                 return;
 290         }
 291 }
 292
 293 static __be32 tb_crc(const void *data, size_t len)
 294 {
 295         return cpu_to_be32(~__crc32c_le(~0, data, len));
 296 }
 297
 298 static void tb_ctl_pkg_free(struct ctl_pkg *pkg)
 299 {
 300         if (pkg) {
 301                 dma_pool_free(pkg->ctl->frame_pool,
 302                               pkg->buffer, pkg->frame.buffer_phy);
 303                 kfree(pkg);
 304         }
 305 }
 306
 307 static struct ctl_pkg *tb_ctl_pkg_alloc(struct tb_ctl *ctl)
 308 {
 309         struct ctl_pkg *pkg = kzalloc(sizeof(*pkg), GFP_KERNEL);
 310         if (!pkg)
 311                 return NULL;
 312         pkg->ctl = ctl;
 313         pkg->buffer = dma_pool_alloc(ctl->frame_pool, GFP_KERNEL,
 314                                      &pkg->frame.buffer_phy);
 315         if (!pkg->buffer) {
 316                 kfree(pkg);
 317                 return NULL;
 318         }
 319         return pkg;
 320 }
 321
 322
 323 /* RX/TX handling */
 324
 325 static void tb_ctl_tx_callback(struct tb_ring *ring, struct ring_frame *frame,
 326                                bool canceled)
 327 {
 328         struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
 329         tb_ctl_pkg_free(pkg);
 330 }
 331
 332 /**
 333  * tb_cfg_tx() - transmit a packet on the control channel
 334  *
 335  * len must be a multiple of four.
 336  *
 337  * Return: Returns 0 on success or an error code on failure.
 338  */
 339 static int tb_ctl_tx(struct tb_ctl *ctl, const void *data, size_t len,
 340                      enum tb_cfg_pkg_type type)
 341 {
 342         int res;
 343         struct ctl_pkg *pkg;
 344         if (len % 4 != 0) { /* required for le->be conversion */
 345                 tb_ctl_WARN(ctl, "TX: invalid size: %zu\n", len);
 346                 return -EINVAL;
 347         }
 348         if (len > TB_FRAME_SIZE - 4) { /* checksum is 4 bytes */
 349                 tb_ctl_WARN(ctl, "TX: packet too large: %zu/%d\n",
 350                             len, TB_FRAME_SIZE - 4);
 351                 return -EINVAL;
 352         }
 353         pkg = tb_ctl_pkg_alloc(ctl);
 354         if (!pkg)
 355                 return -ENOMEM;
 356         pkg->frame.callback = tb_ctl_tx_callback;
 357         pkg->frame.size = len + 4;
 358         pkg->frame.sof = type;
 359         pkg->frame.eof = type;
 360         cpu_to_be32_array(pkg->buffer, data, len / 4);
 361         *(__be32 *) (pkg->buffer + len) = tb_crc(pkg->buffer, len);
 362
 363         res = tb_ring_tx(ctl->tx, &pkg->frame);
 364         if (res) /* ring is stopped */
 365                 tb_ctl_pkg_free(pkg);
 366         return res;
 367 }
 368
 369 /**
 370  * tb_ctl_handle_event() - acknowledge a plug event, invoke ctl->callback
 371  */
 372 static bool tb_ctl_handle_event(struct tb_ctl *ctl, enum tb_cfg_pkg_type type,
 373                                 struct ctl_pkg *pkg, size_t size)
 374 {
 375         return ctl->callback(ctl->callback_data, type, pkg->buffer, size);
 376 }
 377
 378 static void tb_ctl_rx_submit(struct ctl_pkg *pkg)
 379 {
 380         tb_ring_rx(pkg->ctl->rx, &pkg->frame); /*
 381                                              * We ignore failures during stop.
 382                                              * All rx packets are referenced
 383                                              * from ctl->rx_packets, so we do
 384                                              * not loose them.
 385                                              */
 386 }
 387
 388 static int tb_async_error(const struct ctl_pkg *pkg)
 389 {
 390         const struct cfg_error_pkg *error = pkg->buffer;
 391
 392         if (pkg->frame.eof != TB_CFG_PKG_ERROR)
 393                 return false;
 394
 395         switch (error->error) {
 396         case TB_CFG_ERROR_LINK_ERROR:
 397         case TB_CFG_ERROR_HEC_ERROR_DETECTED:
 398         case TB_CFG_ERROR_FLOW_CONTROL_ERROR:
 399                 return true;
 400
 401         default:
 402                 return false;
 403         }
 404 }
 405
 406 static void tb_ctl_rx_callback(struct tb_ring *ring, struct ring_frame *frame,
 407                                bool canceled)
 408 {
 409         struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
 410         struct tb_cfg_request *req;
 411         __be32 crc32;
 412
 413         if (canceled)
 414                 return; /*
 415                          * ring is stopped, packet is referenced from
 416                          * ctl->rx_packets.
 417                          */
 418
 419         if (frame->size < 4 || frame->size % 4 != 0) {
 420                 tb_ctl_err(pkg->ctl, "RX: invalid size %#x, dropping packet\n",
 421                            frame->size);
 422                 goto rx;
 423         }
 424
 425         frame->size -= 4; /* remove checksum */
 426         crc32 = tb_crc(pkg->buffer, frame->size);
 427         be32_to_cpu_array(pkg->buffer, pkg->buffer, frame->size / 4);
 428
 429         switch (frame->eof) {
 430         case TB_CFG_PKG_READ:
 431         case TB_CFG_PKG_WRITE:
 432         case TB_CFG_PKG_ERROR:
 433         case TB_CFG_PKG_OVERRIDE:
 434         case TB_CFG_PKG_RESET:
 435                 if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
 436                         tb_ctl_err(pkg->ctl,
 437                                    "RX: checksum mismatch, dropping packet\n");
 438                         goto rx;
 439                 }
 440                 if (tb_async_error(pkg)) {
 441                         tb_ctl_handle_event(pkg->ctl, frame->eof,
 442                                             pkg, frame->size);
 443                         goto rx;
 444                 }
 445                 break;
 446
 447         case TB_CFG_PKG_EVENT:
 448         case TB_CFG_PKG_XDOMAIN_RESP:
 449         case TB_CFG_PKG_XDOMAIN_REQ:
 450                 if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
 451                         tb_ctl_err(pkg->ctl,
 452                                    "RX: checksum mismatch, dropping packet\n");
 453                         goto rx;
 454                 }
 455                 /* Fall through */
 456         case TB_CFG_PKG_ICM_EVENT:
 457                 if (tb_ctl_handle_event(pkg->ctl, frame->eof, pkg, frame->size))
 458                         goto rx;
 459                 break;
 460
 461         default:
 462                 break;
 463         }
 464
 465         /*
 466          * The received packet will be processed only if there is an
 467          * active request and that the packet is what is expected. This
 468          * prevents packets such as replies coming after timeout has
 469          * triggered from messing with the active requests.
 470          */
 471         req = tb_cfg_request_find(pkg->ctl, pkg);
 472         if (req) {
 473                 if (req->copy(req, pkg))
 474                         schedule_work(&req->work);
 475                 tb_cfg_request_put(req);
 476         }
 477
 478 rx:
 479         tb_ctl_rx_submit(pkg);
 480 }
 481
 482 static void tb_cfg_request_work(struct work_struct *work)
 483 {
 484         struct tb_cfg_request *req = container_of(work, typeof(*req), work);
 485
 486         if (!test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
 487                 req->callback(req->callback_data);
 488
 489         tb_cfg_request_dequeue(req);
 490         tb_cfg_request_put(req);
 491 }
 492
 493 /**
 494  * tb_cfg_request() - Start control request not waiting for it to complete
 495  * @ctl: Control channel to use
 496  * @req: Request to start
 497  * @callback: Callback called when the request is completed
 498  * @callback_data: Data to be passed to @callback
 499  *
 500  * This queues @req on the given control channel without waiting for it
 501  * to complete. When the request completes @callback is called.
 502  */
 503 int tb_cfg_request(struct tb_ctl *ctl, struct tb_cfg_request *req,
 504                    void (*callback)(void *), void *callback_data)
 505 {
 506         int ret;
 507
 508         req->flags = 0;
 509         req->callback = callback;
 510         req->callback_data = callback_data;
 511         INIT_WORK(&req->work, tb_cfg_request_work);
 512         INIT_LIST_HEAD(&req->list);
 513
 514         tb_cfg_request_get(req);
 515         ret = tb_cfg_request_enqueue(ctl, req);
 516         if (ret)
 517                 goto err_put;
 518
 519         ret = tb_ctl_tx(ctl, req->request, req->request_size,
 520                         req->request_type);
 521         if (ret)
 522                 goto err_dequeue;
 523
 524         if (!req->response)
 525                 schedule_work(&req->work);
 526
 527         return 0;
 528
 529 err_dequeue:
 530         tb_cfg_request_dequeue(req);
 531 err_put:
 532         tb_cfg_request_put(req);
 533
 534         return ret;
 535 }
 536
 537 /**
 538  * tb_cfg_request_cancel() - Cancel a control request
 539  * @req: Request to cancel
 540  * @err: Error to assign to the request
 541  *
 542  * This function can be used to cancel ongoing request. It will wait
 543  * until the request is not active anymore.
 544  */
 545 void tb_cfg_request_cancel(struct tb_cfg_request *req, int err)
 546 {
 547         set_bit(TB_CFG_REQUEST_CANCELED, &req->flags);
 548         schedule_work(&req->work);
 549         wait_event(tb_cfg_request_cancel_queue, !tb_cfg_request_is_active(req));
 550         req->result.err = err;
 551 }
 552
 553 static void tb_cfg_request_complete(void *data)
 554 {
 555         complete(data);
 556 }
 557
 558 /**
 559  * tb_cfg_request_sync() - Start control request and wait until it completes
 560  * @ctl: Control channel to use
 561  * @req: Request to start
 562  * @timeout_msec: Timeout how long to wait @req to complete
 563  *
 564  * Starts a control request and waits until it completes. If timeout
 565  * triggers the request is canceled before function returns. Note the
 566  * caller needs to make sure only one message for given switch is active
 567  * at a time.
 568  */
 569 struct tb_cfg_result tb_cfg_request_sync(struct tb_ctl *ctl,
 570                                          struct tb_cfg_request *req,
 571                                          int timeout_msec)
 572 {
 573         unsigned long timeout = msecs_to_jiffies(timeout_msec);
 574         struct tb_cfg_result res = { 0 };
 575         DECLARE_COMPLETION_ONSTACK(done);
 576         int ret;
 577
 578         ret = tb_cfg_request(ctl, req, tb_cfg_request_complete, &done);
 579         if (ret) {
 580                 res.err = ret;
 581                 return res;
 582         }
 583
 584         if (!wait_for_completion_timeout(&done, timeout))
 585                 tb_cfg_request_cancel(req, -ETIMEDOUT);
 586
 587         flush_work(&req->work);
 588
 589         return req->result;
 590 }
 591
 592 /* public interface, alloc/start/stop/free */
 593
 594 /**
 595  * tb_ctl_alloc() - allocate a control channel
 596  *
 597  * cb will be invoked once for every hot plug event.
 598  *
 599  * Return: Returns a pointer on success or NULL on failure.
 600  */
 601 struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, event_cb cb, void *cb_data)
 602 {
 603         int i;
 604         struct tb_ctl *ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
 605         if (!ctl)
 606                 return NULL;
 607         ctl->nhi = nhi;
 608         ctl->callback = cb;
 609         ctl->callback_data = cb_data;
 610
 611         mutex_init(&ctl->request_queue_lock);
 612         INIT_LIST_HEAD(&ctl->request_queue);
 613         ctl->frame_pool = dma_pool_create("thunderbolt_ctl", &nhi->pdev->dev,
 614                                          TB_FRAME_SIZE, 4, 0);
 615         if (!ctl->frame_pool)
 616                 goto err;
 617
 618         ctl->tx = tb_ring_alloc_tx(nhi, 0, 10, RING_FLAG_NO_SUSPEND);
 619         if (!ctl->tx)
 620                 goto err;
 621
 622         ctl->rx = tb_ring_alloc_rx(nhi, 0, 10, RING_FLAG_NO_SUSPEND, 0xffff,
 623                                 0xffff, NULL, NULL);
 624         if (!ctl->rx)
 625                 goto err;
 626
 627         for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++) {
 628                 ctl->rx_packets[i] = tb_ctl_pkg_alloc(ctl);
 629                 if (!ctl->rx_packets[i])
 630                         goto err;
 631                 ctl->rx_packets[i]->frame.callback = tb_ctl_rx_callback;
 632         }
 633
 634         tb_ctl_info(ctl, "control channel created\n");
 635         return ctl;
 636 err:
 637         tb_ctl_free(ctl);
 638         return NULL;
 639 }
 640
 641 /**
 642  * tb_ctl_free() - free a control channel
 643  *
 644  * Must be called after tb_ctl_stop.
 645  *
 646  * Must NOT be called from ctl->callback.
 647  */
 648 void tb_ctl_free(struct tb_ctl *ctl)
 649 {
 650         int i;
 651
 652         if (!ctl)
 653                 return;
 654
 655         if (ctl->rx)
 656                 tb_ring_free(ctl->rx);
 657         if (ctl->tx)
 658                 tb_ring_free(ctl->tx);
 659
 660         /* free RX packets */
 661         for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
 662                 tb_ctl_pkg_free(ctl->rx_packets[i]);
 663
 664
 665         if (ctl->frame_pool)
 666                 dma_pool_destroy(ctl->frame_pool);
 667         kfree(ctl);
 668 }
 669
 670 /**
 671  * tb_cfg_start() - start/resume the control channel
 672  */
 673 void tb_ctl_start(struct tb_ctl *ctl)
 674 {
 675         int i;
 676         tb_ctl_info(ctl, "control channel starting...\n");
 677         tb_ring_start(ctl->tx); /* is used to ack hotplug packets, start first */
 678         tb_ring_start(ctl->rx);
 679         for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
 680                 tb_ctl_rx_submit(ctl->rx_packets[i]);
 681
 682         ctl->running = true;
 683 }
 684
 685 /**
 686  * control() - pause the control channel
 687  *
 688  * All invocations of ctl->callback will have finished after this method
 689  * returns.
 690  *
 691  * Must NOT be called from ctl->callback.
 692  */
 693 void tb_ctl_stop(struct tb_ctl *ctl)
 694 {
 695         mutex_lock(&ctl->request_queue_lock);
 696         ctl->running = false;
 697         mutex_unlock(&ctl->request_queue_lock);
 698
 699         tb_ring_stop(ctl->rx);
 700         tb_ring_stop(ctl->tx);
 701
 702         if (!list_empty(&ctl->request_queue))
 703                 tb_ctl_WARN(ctl, "dangling request in request_queue\n");
 704         INIT_LIST_HEAD(&ctl->request_queue);
 705         tb_ctl_info(ctl, "control channel stopped\n");
 706 }
 707
 708 /* public interface, commands */
 709
 710 /**
 711  * tb_cfg_error() - send error packet
 712  *
 713  * Return: Returns 0 on success or an error code on failure.
 714  */
 715 int tb_cfg_error(struct tb_ctl *ctl, u64 route, u32 port,
 716                  enum tb_cfg_error error)
 717 {
 718         struct cfg_error_pkg pkg = {
 719                 .header = tb_cfg_make_header(route),
 720                 .port = port,
 721                 .error = error,
 722         };
 723         tb_ctl_info(ctl, "resetting error on %llx:%x.\n", route, port);
 724         return tb_ctl_tx(ctl, &pkg, sizeof(pkg), TB_CFG_PKG_ERROR);
 725 }
 726
 727 static bool tb_cfg_match(const struct tb_cfg_request *req,
 728                          const struct ctl_pkg *pkg)
 729 {
 730         u64 route = tb_cfg_get_route(pkg->buffer) & ~BIT_ULL(63);
 731
 732         if (pkg->frame.eof == TB_CFG_PKG_ERROR)
 733                 return true;
 734
 735         if (pkg->frame.eof != req->response_type)
 736                 return false;
 737         if (route != tb_cfg_get_route(req->request))
 738                 return false;
 739         if (pkg->frame.size != req->response_size)
 740                 return false;
 741
 742         if (pkg->frame.eof == TB_CFG_PKG_READ ||
 743             pkg->frame.eof == TB_CFG_PKG_WRITE) {
 744                 const struct cfg_read_pkg *req_hdr = req->request;
 745                 const struct cfg_read_pkg *res_hdr = pkg->buffer;
 746
 747                 if (req_hdr->addr.seq != res_hdr->addr.seq)
 748                         return false;
 749         }
 750
 751         return true;
 752 }
 753
 754 static bool tb_cfg_copy(struct tb_cfg_request *req, const struct ctl_pkg *pkg)
 755 {
 756         struct tb_cfg_result res;
 757
 758         /* Now make sure it is in expected format */
 759         res = parse_header(pkg, req->response_size, req->response_type,
 760                            tb_cfg_get_route(req->request));
 761         if (!res.err)
 762                 memcpy(req->response, pkg->buffer, req->response_size);
 763
 764         req->result = res;
 765
 766         /* Always complete when first response is received */
 767         return true;
 768 }
 769
 770 /**
 771  * tb_cfg_reset() - send a reset packet and wait for a response
 772  *
 773  * If the switch at route is incorrectly configured then we will not receive a
 774  * reply (even though the switch will reset). The caller should check for
 775  * -ETIMEDOUT and attempt to reconfigure the switch.
 776  */
 777 struct tb_cfg_result tb_cfg_reset(struct tb_ctl *ctl, u64 route,
 778                                   int timeout_msec)
 779 {
 780         struct cfg_reset_pkg request = { .header = tb_cfg_make_header(route) };
 781         struct tb_cfg_result res = { 0 };
 782         struct tb_cfg_header reply;
 783         struct tb_cfg_request *req;
 784
 785         req = tb_cfg_request_alloc();
 786         if (!req) {
 787                 res.err = -ENOMEM;
 788                 return res;
 789         }
 790
 791         req->match = tb_cfg_match;
 792         req->copy = tb_cfg_copy;
 793         req->request = &request;
 794         req->request_size = sizeof(request);
 795         req->request_type = TB_CFG_PKG_RESET;
 796         req->response = &reply;
 797         req->response_size = sizeof(reply);
 798         req->response_type = TB_CFG_PKG_RESET;
 799
 800         res = tb_cfg_request_sync(ctl, req, timeout_msec);
 801
 802         tb_cfg_request_put(req);
 803
 804         return res;
 805 }
 806
 807 /**
 808  * tb_cfg_read() - read from config space into buffer
 809  *
 810  * Offset and length are in dwords.
 811  */
 812 struct tb_cfg_result tb_cfg_read_raw(struct tb_ctl *ctl, void *buffer,
 813                 u64 route, u32 port, enum tb_cfg_space space,
 814                 u32 offset, u32 length, int timeout_msec)
 815 {
 816         struct tb_cfg_result res = { 0 };
 817         struct cfg_read_pkg request = {
 818                 .header = tb_cfg_make_header(route),
 819                 .addr = {
 820                         .port = port,
 821                         .space = space,
 822                         .offset = offset,
 823                         .length = length,
 824                 },
 825         };
 826         struct cfg_write_pkg reply;
 827         int retries = 0;
 828
 829         while (retries < TB_CTL_RETRIES) {
 830                 struct tb_cfg_request *req;
 831
 832                 req = tb_cfg_request_alloc();
 833                 if (!req) {
 834                         res.err = -ENOMEM;
 835                         return res;
 836                 }
 837
 838                 request.addr.seq = retries++;
 839
 840                 req->match = tb_cfg_match;
 841                 req->copy = tb_cfg_copy;
 842                 req->request = &request;
 843                 req->request_size = sizeof(request);
 844                 req->request_type = TB_CFG_PKG_READ;
 845                 req->response = &reply;
 846                 req->response_size = 12 + 4 * length;
 847                 req->response_type = TB_CFG_PKG_READ;
 848
 849                 res = tb_cfg_request_sync(ctl, req, timeout_msec);
 850
 851                 tb_cfg_request_put(req);
 852
 853                 if (res.err != -ETIMEDOUT)
 854                         break;
 855
 856                 /* Wait a bit (arbitrary time) until we send a retry */
 857                 usleep_range(10, 100);
 858         }
 859
 860         if (res.err)
 861                 return res;
 862
 863         res.response_port = reply.addr.port;
 864         res.err = check_config_address(reply.addr, space, offset, length);
 865         if (!res.err)
 866                 memcpy(buffer, &reply.data, 4 * length);
 867         return res;
 868 }
 869
 870 /**
 871  * tb_cfg_write() - write from buffer into config space
 872  *
 873  * Offset and length are in dwords.
 874  */
 875 struct tb_cfg_result tb_cfg_write_raw(struct tb_ctl *ctl, const void *buffer,
 876                 u64 route, u32 port, enum tb_cfg_space space,
 877                 u32 offset, u32 length, int timeout_msec)
 878 {
 879         struct tb_cfg_result res = { 0 };
 880         struct cfg_write_pkg request = {
 881                 .header = tb_cfg_make_header(route),
 882                 .addr = {
 883                         .port = port,
 884                         .space = space,
 885                         .offset = offset,
 886                         .length = length,
 887                 },
 888         };
 889         struct cfg_read_pkg reply;
 890         int retries = 0;
 891
 892         memcpy(&request.data, buffer, length * 4);
 893
 894         while (retries < TB_CTL_RETRIES) {
 895                 struct tb_cfg_request *req;
 896
 897                 req = tb_cfg_request_alloc();
 898                 if (!req) {
 899                         res.err = -ENOMEM;
 900                         return res;
 901                 }
 902
 903                 request.addr.seq = retries++;
 904
 905                 req->match = tb_cfg_match;
 906                 req->copy = tb_cfg_copy;
 907                 req->request = &request;
 908                 req->request_size = 12 + 4 * length;
 909                 req->request_type = TB_CFG_PKG_WRITE;
 910                 req->response = &reply;
 911                 req->response_size = sizeof(reply);
 912                 req->response_type = TB_CFG_PKG_WRITE;
 913
 914                 res = tb_cfg_request_sync(ctl, req, timeout_msec);
 915
 916                 tb_cfg_request_put(req);
 917
 918                 if (res.err != -ETIMEDOUT)
 919                         break;
 920
 921                 /* Wait a bit (arbitrary time) until we send a retry */
 922                 usleep_range(10, 100);
 923         }
 924
 925         if (res.err)
 926                 return res;
 927
 928         res.response_port = reply.addr.port;
 929         res.err = check_config_address(reply.addr, space, offset, length);
 930         return res;
 931 }
 932
 933 int tb_cfg_read(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
 934                 enum tb_cfg_space space, u32 offset, u32 length)
 935 {
 936         struct tb_cfg_result res = tb_cfg_read_raw(ctl, buffer, route, port,
 937                         space, offset, length, TB_CFG_DEFAULT_TIMEOUT);
 938         switch (res.err) {
 939         case 0:
 940                 /* Success */
 941                 break;
 942
 943         case 1:
 944                 /* Thunderbolt error, tb_error holds the actual number */
 945                 tb_cfg_print_error(ctl, &res);
 946                 return -EIO;
 947
 948         case -ETIMEDOUT:
 949                 tb_ctl_warn(ctl, "timeout reading config space %u from %#x\n",
 950                             space, offset);
 951                 break;
 952
 953         default:
 954                 WARN(1, "tb_cfg_read: %d\n", res.err);
 955                 break;
 956         }
 957         return res.err;
 958 }
 959
 960 int tb_cfg_write(struct tb_ctl *ctl, const void *buffer, u64 route, u32 port,
 961                  enum tb_cfg_space space, u32 offset, u32 length)
 962 {
 963         struct tb_cfg_result res = tb_cfg_write_raw(ctl, buffer, route, port,
 964                         space, offset, length, TB_CFG_DEFAULT_TIMEOUT);
 965         switch (res.err) {
 966         case 0:
 967                 /* Success */
 968                 break;
 969
 970         case 1:
 971                 /* Thunderbolt error, tb_error holds the actual number */
 972                 tb_cfg_print_error(ctl, &res);
 973                 return -EIO;
 974
 975         case -ETIMEDOUT:
 976                 tb_ctl_warn(ctl, "timeout writing config space %u to %#x\n",
 977                             space, offset);
 978                 break;
 979
 980         default:
 981                 WARN(1, "tb_cfg_write: %d\n", res.err);
 982                 break;
 983         }
 984         return res.err;
 985 }
 986
 987 /**
 988  * tb_cfg_get_upstream_port() - get upstream port number of switch at route
 989  *
 990  * Reads the first dword from the switches TB_CFG_SWITCH config area and
 991  * returns the port number from which the reply originated.
 992  *
 993  * Return: Returns the upstream port number on success or an error code on
 994  * failure.
 995  */
 996 int tb_cfg_get_upstream_port(struct tb_ctl *ctl, u64 route)
 997 {
 998         u32 dummy;
 999         struct tb_cfg_result res = tb_cfg_read_raw(ctl, &dummy, route, 0,
1000                                                    TB_CFG_SWITCH, 0, 1,
1001                                                    TB_CFG_DEFAULT_TIMEOUT);
1002         if (res.err == 1)
1003                 return -EIO;
1004         if (res.err)
1005                 return res.err;
1006         return res.response_port;
1007 }