drivers/thunderbolt/ctl.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Thunderbolt driver - control channel and configuration commands
   4  *
   5  * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
   6  * Copyright (C) 2018, Intel Corporation
   7  */
   8
   9 #include <linux/crc32.h>
  10 #include <linux/delay.h>
  11 #include <linux/slab.h>
  12 #include <linux/pci.h>
  13 #include <linux/dmapool.h>
  14 #include <linux/workqueue.h>
  15
  16 #include "ctl.h"
  17
  18
  19 #define TB_CTL_RX_PKG_COUNT     10
  20 #define TB_CTL_RETRIES          4
  21
  22 /**
  23  * struct tb_cfg - thunderbolt control channel
  24  */
  25 struct tb_ctl {
  26         struct tb_nhi *nhi;
  27         struct tb_ring *tx;
  28         struct tb_ring *rx;
  29
  30         struct dma_pool *frame_pool;
  31         struct ctl_pkg *rx_packets[TB_CTL_RX_PKG_COUNT];
  32         struct mutex request_queue_lock;
  33         struct list_head request_queue;
  34         bool running;
  35
  36         event_cb callback;
  37         void *callback_data;
  38 };
  39
  40
  41 #define tb_ctl_WARN(ctl, format, arg...) \
  42         dev_WARN(&(ctl)->nhi->pdev->dev, format, ## arg)
  43
  44 #define tb_ctl_err(ctl, format, arg...) \
  45         dev_err(&(ctl)->nhi->pdev->dev, format, ## arg)
  46
  47 #define tb_ctl_warn(ctl, format, arg...) \
  48         dev_warn(&(ctl)->nhi->pdev->dev, format, ## arg)
  49
  50 #define tb_ctl_info(ctl, format, arg...) \
  51         dev_info(&(ctl)->nhi->pdev->dev, format, ## arg)
  52
  53 #define tb_ctl_dbg(ctl, format, arg...) \
  54         dev_dbg(&(ctl)->nhi->pdev->dev, format, ## arg)
  55
  56 static DECLARE_WAIT_QUEUE_HEAD(tb_cfg_request_cancel_queue);
  57 /* Serializes access to request kref_get/put */
  58 static DEFINE_MUTEX(tb_cfg_request_lock);
  59
  60 /**
  61  * tb_cfg_request_alloc() - Allocates a new config request
  62  *
  63  * This is refcounted object so when you are done with this, call
  64  * tb_cfg_request_put() to it.
  65  */
  66 struct tb_cfg_request *tb_cfg_request_alloc(void)
  67 {
  68         struct tb_cfg_request *req;
  69
  70         req = kzalloc(sizeof(*req), GFP_KERNEL);
  71         if (!req)
  72                 return NULL;
  73
  74         kref_init(&req->kref);
  75
  76         return req;
  77 }
  78
  79 /**
  80  * tb_cfg_request_get() - Increase refcount of a request
  81  * @req: Request whose refcount is increased
  82  */
  83 void tb_cfg_request_get(struct tb_cfg_request *req)
  84 {
  85         mutex_lock(&tb_cfg_request_lock);
  86         kref_get(&req->kref);
  87         mutex_unlock(&tb_cfg_request_lock);
  88 }
  89
  90 static void tb_cfg_request_destroy(struct kref *kref)
  91 {
  92         struct tb_cfg_request *req = container_of(kref, typeof(*req), kref);
  93
  94         kfree(req);
  95 }
  96
  97 /**
  98  * tb_cfg_request_put() - Decrease refcount and possibly release the request
  99  * @req: Request whose refcount is decreased
 100  *
 101  * Call this function when you are done with the request. When refcount
 102  * goes to %0 the object is released.
 103  */
 104 void tb_cfg_request_put(struct tb_cfg_request *req)
 105 {
 106         mutex_lock(&tb_cfg_request_lock);
 107         kref_put(&req->kref, tb_cfg_request_destroy);
 108         mutex_unlock(&tb_cfg_request_lock);
 109 }
 110
 111 static int tb_cfg_request_enqueue(struct tb_ctl *ctl,
 112                                   struct tb_cfg_request *req)
 113 {
 114         WARN_ON(test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags));
 115         WARN_ON(req->ctl);
 116
 117         mutex_lock(&ctl->request_queue_lock);
 118         if (!ctl->running) {
 119                 mutex_unlock(&ctl->request_queue_lock);
 120                 return -ENOTCONN;
 121         }
 122         req->ctl = ctl;
 123         list_add_tail(&req->list, &ctl->request_queue);
 124         set_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
 125         mutex_unlock(&ctl->request_queue_lock);
 126         return 0;
 127 }
 128
 129 static void tb_cfg_request_dequeue(struct tb_cfg_request *req)
 130 {
 131         struct tb_ctl *ctl = req->ctl;
 132
 133         mutex_lock(&ctl->request_queue_lock);
 134         list_del(&req->list);
 135         clear_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
 136         if (test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
 137                 wake_up(&tb_cfg_request_cancel_queue);
 138         mutex_unlock(&ctl->request_queue_lock);
 139 }
 140
 141 static bool tb_cfg_request_is_active(struct tb_cfg_request *req)
 142 {
 143         return test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
 144 }
 145
 146 static struct tb_cfg_request *
 147 tb_cfg_request_find(struct tb_ctl *ctl, struct ctl_pkg *pkg)
 148 {
 149         struct tb_cfg_request *req;
 150         bool found = false;
 151
 152         mutex_lock(&pkg->ctl->request_queue_lock);
 153         list_for_each_entry(req, &pkg->ctl->request_queue, list) {
 154                 tb_cfg_request_get(req);
 155                 if (req->match(req, pkg)) {
 156                         found = true;
 157                         break;
 158                 }
 159                 tb_cfg_request_put(req);
 160         }
 161         mutex_unlock(&pkg->ctl->request_queue_lock);
 162
 163         return found ? req : NULL;
 164 }
 165
 166 /* utility functions */
 167
 168
 169 static int check_header(const struct ctl_pkg *pkg, u32 len,
 170                         enum tb_cfg_pkg_type type, u64 route)
 171 {
 172         struct tb_cfg_header *header = pkg->buffer;
 173
 174         /* check frame, TODO: frame flags */
 175         if (WARN(len != pkg->frame.size,
 176                         "wrong framesize (expected %#x, got %#x)\n",
 177                         len, pkg->frame.size))
 178                 return -EIO;
 179         if (WARN(type != pkg->frame.eof, "wrong eof (expected %#x, got %#x)\n",
 180                         type, pkg->frame.eof))
 181                 return -EIO;
 182         if (WARN(pkg->frame.sof, "wrong sof (expected 0x0, got %#x)\n",
 183                         pkg->frame.sof))
 184                 return -EIO;
 185
 186         /* check header */
 187         if (WARN(header->unknown != 1 << 9,
 188                         "header->unknown is %#x\n", header->unknown))
 189                 return -EIO;
 190         if (WARN(route != tb_cfg_get_route(header),
 191                         "wrong route (expected %llx, got %llx)",
 192                         route, tb_cfg_get_route(header)))
 193                 return -EIO;
 194         return 0;
 195 }
 196
 197 static int check_config_address(struct tb_cfg_address addr,
 198                                 enum tb_cfg_space space, u32 offset,
 199                                 u32 length)
 200 {
 201         if (WARN(addr.zero, "addr.zero is %#x\n", addr.zero))
 202                 return -EIO;
 203         if (WARN(space != addr.space, "wrong space (expected %x, got %x\n)",
 204                         space, addr.space))
 205                 return -EIO;
 206         if (WARN(offset != addr.offset, "wrong offset (expected %x, got %x\n)",
 207                         offset, addr.offset))
 208                 return -EIO;
 209         if (WARN(length != addr.length, "wrong space (expected %x, got %x\n)",
 210                         length, addr.length))
 211                 return -EIO;
 212         /*
 213          * We cannot check addr->port as it is set to the upstream port of the
 214          * sender.
 215          */
 216         return 0;
 217 }
 218
 219 static struct tb_cfg_result decode_error(const struct ctl_pkg *response)
 220 {
 221         struct cfg_error_pkg *pkg = response->buffer;
 222         struct tb_cfg_result res = { 0 };
 223         res.response_route = tb_cfg_get_route(&pkg->header);
 224         res.response_port = 0;
 225         res.err = check_header(response, sizeof(*pkg), TB_CFG_PKG_ERROR,
 226                                tb_cfg_get_route(&pkg->header));
 227         if (res.err)
 228                 return res;
 229
 230         WARN(pkg->zero1, "pkg->zero1 is %#x\n", pkg->zero1);
 231         WARN(pkg->zero2, "pkg->zero1 is %#x\n", pkg->zero1);
 232         WARN(pkg->zero3, "pkg->zero1 is %#x\n", pkg->zero1);
 233         res.err = 1;
 234         res.tb_error = pkg->error;
 235         res.response_port = pkg->port;
 236         return res;
 237
 238 }
 239
 240 static struct tb_cfg_result parse_header(const struct ctl_pkg *pkg, u32 len,
 241                                          enum tb_cfg_pkg_type type, u64 route)
 242 {
 243         struct tb_cfg_header *header = pkg->buffer;
 244         struct tb_cfg_result res = { 0 };
 245
 246         if (pkg->frame.eof == TB_CFG_PKG_ERROR)
 247                 return decode_error(pkg);
 248
 249         res.response_port = 0; /* will be updated later for cfg_read/write */
 250         res.response_route = tb_cfg_get_route(header);
 251         res.err = check_header(pkg, len, type, route);
 252         return res;
 253 }
 254
 255 static void tb_cfg_print_error(struct tb_ctl *ctl,
 256                                const struct tb_cfg_result *res)
 257 {
 258         WARN_ON(res->err != 1);
 259         switch (res->tb_error) {
 260         case TB_CFG_ERROR_PORT_NOT_CONNECTED:
 261                 /* Port is not connected. This can happen during surprise
 262                  * removal. Do not warn. */
 263                 return;
 264         case TB_CFG_ERROR_INVALID_CONFIG_SPACE:
 265                 /*
 266                  * Invalid cfg_space/offset/length combination in
 267                  * cfg_read/cfg_write.
 268                  */
 269                 tb_ctl_WARN(ctl,
 270                         "CFG_ERROR(%llx:%x): Invalid config space or offset\n",
 271                         res->response_route, res->response_port);
 272                 return;
 273         case TB_CFG_ERROR_NO_SUCH_PORT:
 274                 /*
 275                  * - The route contains a non-existent port.
 276                  * - The route contains a non-PHY port (e.g. PCIe).
 277                  * - The port in cfg_read/cfg_write does not exist.
 278                  */
 279                 tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Invalid port\n",
 280                         res->response_route, res->response_port);
 281                 return;
 282         case TB_CFG_ERROR_LOOP:
 283                 tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Route contains a loop\n",
 284                         res->response_route, res->response_port);
 285                 return;
 286         default:
 287                 /* 5,6,7,9 and 11 are also valid error codes */
 288                 tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Unknown error\n",
 289                         res->response_route, res->response_port);
 290                 return;
 291         }
 292 }
 293
 294 static __be32 tb_crc(const void *data, size_t len)
 295 {
 296         return cpu_to_be32(~__crc32c_le(~0, data, len));
 297 }
 298
 299 static void tb_ctl_pkg_free(struct ctl_pkg *pkg)
 300 {
 301         if (pkg) {
 302                 dma_pool_free(pkg->ctl->frame_pool,
 303                               pkg->buffer, pkg->frame.buffer_phy);
 304                 kfree(pkg);
 305         }
 306 }
 307
 308 static struct ctl_pkg *tb_ctl_pkg_alloc(struct tb_ctl *ctl)
 309 {
 310         struct ctl_pkg *pkg = kzalloc(sizeof(*pkg), GFP_KERNEL);
 311         if (!pkg)
 312                 return NULL;
 313         pkg->ctl = ctl;
 314         pkg->buffer = dma_pool_alloc(ctl->frame_pool, GFP_KERNEL,
 315                                      &pkg->frame.buffer_phy);
 316         if (!pkg->buffer) {
 317                 kfree(pkg);
 318                 return NULL;
 319         }
 320         return pkg;
 321 }
 322
 323
 324 /* RX/TX handling */
 325
 326 static void tb_ctl_tx_callback(struct tb_ring *ring, struct ring_frame *frame,
 327                                bool canceled)
 328 {
 329         struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
 330         tb_ctl_pkg_free(pkg);
 331 }
 332
 333 /**
 334  * tb_cfg_tx() - transmit a packet on the control channel
 335  *
 336  * len must be a multiple of four.
 337  *
 338  * Return: Returns 0 on success or an error code on failure.
 339  */
 340 static int tb_ctl_tx(struct tb_ctl *ctl, const void *data, size_t len,
 341                      enum tb_cfg_pkg_type type)
 342 {
 343         int res;
 344         struct ctl_pkg *pkg;
 345         if (len % 4 != 0) { /* required for le->be conversion */
 346                 tb_ctl_WARN(ctl, "TX: invalid size: %zu\n", len);
 347                 return -EINVAL;
 348         }
 349         if (len > TB_FRAME_SIZE - 4) { /* checksum is 4 bytes */
 350                 tb_ctl_WARN(ctl, "TX: packet too large: %zu/%d\n",
 351                             len, TB_FRAME_SIZE - 4);
 352                 return -EINVAL;
 353         }
 354         pkg = tb_ctl_pkg_alloc(ctl);
 355         if (!pkg)
 356                 return -ENOMEM;
 357         pkg->frame.callback = tb_ctl_tx_callback;
 358         pkg->frame.size = len + 4;
 359         pkg->frame.sof = type;
 360         pkg->frame.eof = type;
 361         cpu_to_be32_array(pkg->buffer, data, len / 4);
 362         *(__be32 *) (pkg->buffer + len) = tb_crc(pkg->buffer, len);
 363
 364         res = tb_ring_tx(ctl->tx, &pkg->frame);
 365         if (res) /* ring is stopped */
 366                 tb_ctl_pkg_free(pkg);
 367         return res;
 368 }
 369
 370 /**
 371  * tb_ctl_handle_event() - acknowledge a plug event, invoke ctl->callback
 372  */
 373 static bool tb_ctl_handle_event(struct tb_ctl *ctl, enum tb_cfg_pkg_type type,
 374                                 struct ctl_pkg *pkg, size_t size)
 375 {
 376         return ctl->callback(ctl->callback_data, type, pkg->buffer, size);
 377 }
 378
 379 static void tb_ctl_rx_submit(struct ctl_pkg *pkg)
 380 {
 381         tb_ring_rx(pkg->ctl->rx, &pkg->frame); /*
 382                                              * We ignore failures during stop.
 383                                              * All rx packets are referenced
 384                                              * from ctl->rx_packets, so we do
 385                                              * not loose them.
 386                                              */
 387 }
 388
 389 static int tb_async_error(const struct ctl_pkg *pkg)
 390 {
 391         const struct cfg_error_pkg *error = (const struct cfg_error_pkg *)pkg;
 392
 393         if (pkg->frame.eof != TB_CFG_PKG_ERROR)
 394                 return false;
 395
 396         switch (error->error) {
 397         case TB_CFG_ERROR_LINK_ERROR:
 398         case TB_CFG_ERROR_HEC_ERROR_DETECTED:
 399         case TB_CFG_ERROR_FLOW_CONTROL_ERROR:
 400                 return true;
 401
 402         default:
 403                 return false;
 404         }
 405 }
 406
 407 static void tb_ctl_rx_callback(struct tb_ring *ring, struct ring_frame *frame,
 408                                bool canceled)
 409 {
 410         struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
 411         struct tb_cfg_request *req;
 412         __be32 crc32;
 413
 414         if (canceled)
 415                 return; /*
 416                          * ring is stopped, packet is referenced from
 417                          * ctl->rx_packets.
 418                          */
 419
 420         if (frame->size < 4 || frame->size % 4 != 0) {
 421                 tb_ctl_err(pkg->ctl, "RX: invalid size %#x, dropping packet\n",
 422                            frame->size);
 423                 goto rx;
 424         }
 425
 426         frame->size -= 4; /* remove checksum */
 427         crc32 = tb_crc(pkg->buffer, frame->size);
 428         be32_to_cpu_array(pkg->buffer, pkg->buffer, frame->size / 4);
 429
 430         switch (frame->eof) {
 431         case TB_CFG_PKG_READ:
 432         case TB_CFG_PKG_WRITE:
 433         case TB_CFG_PKG_ERROR:
 434         case TB_CFG_PKG_OVERRIDE:
 435         case TB_CFG_PKG_RESET:
 436                 if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
 437                         tb_ctl_err(pkg->ctl,
 438                                    "RX: checksum mismatch, dropping packet\n");
 439                         goto rx;
 440                 }
 441                 if (tb_async_error(pkg)) {
 442                         tb_ctl_handle_event(pkg->ctl, frame->eof,
 443                                             pkg, frame->size);
 444                         goto rx;
 445                 }
 446                 break;
 447
 448         case TB_CFG_PKG_EVENT:
 449         case TB_CFG_PKG_XDOMAIN_RESP:
 450         case TB_CFG_PKG_XDOMAIN_REQ:
 451                 if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
 452                         tb_ctl_err(pkg->ctl,
 453                                    "RX: checksum mismatch, dropping packet\n");
 454                         goto rx;
 455                 }
 456                 /* Fall through */
 457         case TB_CFG_PKG_ICM_EVENT:
 458                 if (tb_ctl_handle_event(pkg->ctl, frame->eof, pkg, frame->size))
 459                         goto rx;
 460                 break;
 461
 462         default:
 463                 break;
 464         }
 465
 466         /*
 467          * The received packet will be processed only if there is an
 468          * active request and that the packet is what is expected. This
 469          * prevents packets such as replies coming after timeout has
 470          * triggered from messing with the active requests.
 471          */
 472         req = tb_cfg_request_find(pkg->ctl, pkg);
 473         if (req) {
 474                 if (req->copy(req, pkg))
 475                         schedule_work(&req->work);
 476                 tb_cfg_request_put(req);
 477         }
 478
 479 rx:
 480         tb_ctl_rx_submit(pkg);
 481 }
 482
 483 static void tb_cfg_request_work(struct work_struct *work)
 484 {
 485         struct tb_cfg_request *req = container_of(work, typeof(*req), work);
 486
 487         if (!test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
 488                 req->callback(req->callback_data);
 489
 490         tb_cfg_request_dequeue(req);
 491         tb_cfg_request_put(req);
 492 }
 493
 494 /**
 495  * tb_cfg_request() - Start control request not waiting for it to complete
 496  * @ctl: Control channel to use
 497  * @req: Request to start
 498  * @callback: Callback called when the request is completed
 499  * @callback_data: Data to be passed to @callback
 500  *
 501  * This queues @req on the given control channel without waiting for it
 502  * to complete. When the request completes @callback is called.
 503  */
 504 int tb_cfg_request(struct tb_ctl *ctl, struct tb_cfg_request *req,
 505                    void (*callback)(void *), void *callback_data)
 506 {
 507         int ret;
 508
 509         req->flags = 0;
 510         req->callback = callback;
 511         req->callback_data = callback_data;
 512         INIT_WORK(&req->work, tb_cfg_request_work);
 513         INIT_LIST_HEAD(&req->list);
 514
 515         tb_cfg_request_get(req);
 516         ret = tb_cfg_request_enqueue(ctl, req);
 517         if (ret)
 518                 goto err_put;
 519
 520         ret = tb_ctl_tx(ctl, req->request, req->request_size,
 521                         req->request_type);
 522         if (ret)
 523                 goto err_dequeue;
 524
 525         if (!req->response)
 526                 schedule_work(&req->work);
 527
 528         return 0;
 529
 530 err_dequeue:
 531         tb_cfg_request_dequeue(req);
 532 err_put:
 533         tb_cfg_request_put(req);
 534
 535         return ret;
 536 }
 537
 538 /**
 539  * tb_cfg_request_cancel() - Cancel a control request
 540  * @req: Request to cancel
 541  * @err: Error to assign to the request
 542  *
 543  * This function can be used to cancel ongoing request. It will wait
 544  * until the request is not active anymore.
 545  */
 546 void tb_cfg_request_cancel(struct tb_cfg_request *req, int err)
 547 {
 548         set_bit(TB_CFG_REQUEST_CANCELED, &req->flags);
 549         schedule_work(&req->work);
 550         wait_event(tb_cfg_request_cancel_queue, !tb_cfg_request_is_active(req));
 551         req->result.err = err;
 552 }
 553
 554 static void tb_cfg_request_complete(void *data)
 555 {
 556         complete(data);
 557 }
 558
 559 /**
 560  * tb_cfg_request_sync() - Start control request and wait until it completes
 561  * @ctl: Control channel to use
 562  * @req: Request to start
 563  * @timeout_msec: Timeout how long to wait @req to complete
 564  *
 565  * Starts a control request and waits until it completes. If timeout
 566  * triggers the request is canceled before function returns. Note the
 567  * caller needs to make sure only one message for given switch is active
 568  * at a time.
 569  */
 570 struct tb_cfg_result tb_cfg_request_sync(struct tb_ctl *ctl,
 571                                          struct tb_cfg_request *req,
 572                                          int timeout_msec)
 573 {
 574         unsigned long timeout = msecs_to_jiffies(timeout_msec);
 575         struct tb_cfg_result res = { 0 };
 576         DECLARE_COMPLETION_ONSTACK(done);
 577         int ret;
 578
 579         ret = tb_cfg_request(ctl, req, tb_cfg_request_complete, &done);
 580         if (ret) {
 581                 res.err = ret;
 582                 return res;
 583         }
 584
 585         if (!wait_for_completion_timeout(&done, timeout))
 586                 tb_cfg_request_cancel(req, -ETIMEDOUT);
 587
 588         flush_work(&req->work);
 589
 590         return req->result;
 591 }
 592
 593 /* public interface, alloc/start/stop/free */
 594
 595 /**
 596  * tb_ctl_alloc() - allocate a control channel
 597  *
 598  * cb will be invoked once for every hot plug event.
 599  *
 600  * Return: Returns a pointer on success or NULL on failure.
 601  */
 602 struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, event_cb cb, void *cb_data)
 603 {
 604         int i;
 605         struct tb_ctl *ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
 606         if (!ctl)
 607                 return NULL;
 608         ctl->nhi = nhi;
 609         ctl->callback = cb;
 610         ctl->callback_data = cb_data;
 611
 612         mutex_init(&ctl->request_queue_lock);
 613         INIT_LIST_HEAD(&ctl->request_queue);
 614         ctl->frame_pool = dma_pool_create("thunderbolt_ctl", &nhi->pdev->dev,
 615                                          TB_FRAME_SIZE, 4, 0);
 616         if (!ctl->frame_pool)
 617                 goto err;
 618
 619         ctl->tx = tb_ring_alloc_tx(nhi, 0, 10, RING_FLAG_NO_SUSPEND);
 620         if (!ctl->tx)
 621                 goto err;
 622
 623         ctl->rx = tb_ring_alloc_rx(nhi, 0, 10, RING_FLAG_NO_SUSPEND, 0xffff,
 624                                 0xffff, NULL, NULL);
 625         if (!ctl->rx)
 626                 goto err;
 627
 628         for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++) {
 629                 ctl->rx_packets[i] = tb_ctl_pkg_alloc(ctl);
 630                 if (!ctl->rx_packets[i])
 631                         goto err;
 632                 ctl->rx_packets[i]->frame.callback = tb_ctl_rx_callback;
 633         }
 634
 635         tb_ctl_dbg(ctl, "control channel created\n");
 636         return ctl;
 637 err:
 638         tb_ctl_free(ctl);
 639         return NULL;
 640 }
 641
 642 /**
 643  * tb_ctl_free() - free a control channel
 644  *
 645  * Must be called after tb_ctl_stop.
 646  *
 647  * Must NOT be called from ctl->callback.
 648  */
 649 void tb_ctl_free(struct tb_ctl *ctl)
 650 {
 651         int i;
 652
 653         if (!ctl)
 654                 return;
 655
 656         if (ctl->rx)
 657                 tb_ring_free(ctl->rx);
 658         if (ctl->tx)
 659                 tb_ring_free(ctl->tx);
 660
 661         /* free RX packets */
 662         for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
 663                 tb_ctl_pkg_free(ctl->rx_packets[i]);
 664
 665
 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_dbg(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_dbg(ctl, "control channel stopped\n");
 706 }
 707
 708 /* public interface, commands */
 709
 710 /**
 711  * tb_cfg_ack_plug() - Ack hot plug/unplug event
 712  * @ctl: Control channel to use
 713  * @route: Router that originated the event
 714  * @port: Port where the hot plug/unplug happened
 715  * @unplug: Ack hot plug or unplug
 716  *
 717  * Call this as response for hot plug/unplug event to ack it.
 718  * Returns %0 on success or an error code on failure.
 719  */
 720 int tb_cfg_ack_plug(struct tb_ctl *ctl, u64 route, u32 port, bool unplug)
 721 {
 722         struct cfg_error_pkg pkg = {
 723                 .header = tb_cfg_make_header(route),
 724                 .port = port,
 725                 .error = TB_CFG_ERROR_ACK_PLUG_EVENT,
 726                 .pg = unplug ? TB_CFG_ERROR_PG_HOT_UNPLUG
 727                              : TB_CFG_ERROR_PG_HOT_PLUG,
 728         };
 729         tb_ctl_dbg(ctl, "acking hot %splug event on %llx:%x\n",
 730                    unplug ? "un" : "", route, port);
 731         return tb_ctl_tx(ctl, &pkg, sizeof(pkg), TB_CFG_PKG_ERROR);
 732 }
 733
 734 static bool tb_cfg_match(const struct tb_cfg_request *req,
 735                          const struct ctl_pkg *pkg)
 736 {
 737         u64 route = tb_cfg_get_route(pkg->buffer) & ~BIT_ULL(63);
 738
 739         if (pkg->frame.eof == TB_CFG_PKG_ERROR)
 740                 return true;
 741
 742         if (pkg->frame.eof != req->response_type)
 743                 return false;
 744         if (route != tb_cfg_get_route(req->request))
 745                 return false;
 746         if (pkg->frame.size != req->response_size)
 747                 return false;
 748
 749         if (pkg->frame.eof == TB_CFG_PKG_READ ||
 750             pkg->frame.eof == TB_CFG_PKG_WRITE) {
 751                 const struct cfg_read_pkg *req_hdr = req->request;
 752                 const struct cfg_read_pkg *res_hdr = pkg->buffer;
 753
 754                 if (req_hdr->addr.seq != res_hdr->addr.seq)
 755                         return false;
 756         }
 757
 758         return true;
 759 }
 760
 761 static bool tb_cfg_copy(struct tb_cfg_request *req, const struct ctl_pkg *pkg)
 762 {
 763         struct tb_cfg_result res;
 764
 765         /* Now make sure it is in expected format */
 766         res = parse_header(pkg, req->response_size, req->response_type,
 767                            tb_cfg_get_route(req->request));
 768         if (!res.err)
 769                 memcpy(req->response, pkg->buffer, req->response_size);
 770
 771         req->result = res;
 772
 773         /* Always complete when first response is received */
 774         return true;
 775 }
 776
 777 /**
 778  * tb_cfg_reset() - send a reset packet and wait for a response
 779  *
 780  * If the switch at route is incorrectly configured then we will not receive a
 781  * reply (even though the switch will reset). The caller should check for
 782  * -ETIMEDOUT and attempt to reconfigure the switch.
 783  */
 784 struct tb_cfg_result tb_cfg_reset(struct tb_ctl *ctl, u64 route,
 785                                   int timeout_msec)
 786 {
 787         struct cfg_reset_pkg request = { .header = tb_cfg_make_header(route) };
 788         struct tb_cfg_result res = { 0 };
 789         struct tb_cfg_header reply;
 790         struct tb_cfg_request *req;
 791
 792         req = tb_cfg_request_alloc();
 793         if (!req) {
 794                 res.err = -ENOMEM;
 795                 return res;
 796         }
 797
 798         req->match = tb_cfg_match;
 799         req->copy = tb_cfg_copy;
 800         req->request = &request;
 801         req->request_size = sizeof(request);
 802         req->request_type = TB_CFG_PKG_RESET;
 803         req->response = &reply;
 804         req->response_size = sizeof(reply);
 805         req->response_type = TB_CFG_PKG_RESET;
 806
 807         res = tb_cfg_request_sync(ctl, req, timeout_msec);
 808
 809         tb_cfg_request_put(req);
 810
 811         return res;
 812 }
 813
 814 /**
 815  * tb_cfg_read() - read from config space into buffer
 816  *
 817  * Offset and length are in dwords.
 818  */
 819 struct tb_cfg_result tb_cfg_read_raw(struct tb_ctl *ctl, void *buffer,
 820                 u64 route, u32 port, enum tb_cfg_space space,
 821                 u32 offset, u32 length, int timeout_msec)
 822 {
 823         struct tb_cfg_result res = { 0 };
 824         struct cfg_read_pkg request = {
 825                 .header = tb_cfg_make_header(route),
 826                 .addr = {
 827                         .port = port,
 828                         .space = space,
 829                         .offset = offset,
 830                         .length = length,
 831                 },
 832         };
 833         struct cfg_write_pkg reply;
 834         int retries = 0;
 835
 836         while (retries < TB_CTL_RETRIES) {
 837                 struct tb_cfg_request *req;
 838
 839                 req = tb_cfg_request_alloc();
 840                 if (!req) {
 841                         res.err = -ENOMEM;
 842                         return res;
 843                 }
 844
 845                 request.addr.seq = retries++;
 846
 847                 req->match = tb_cfg_match;
 848                 req->copy = tb_cfg_copy;
 849                 req->request = &request;
 850                 req->request_size = sizeof(request);
 851                 req->request_type = TB_CFG_PKG_READ;
 852                 req->response = &reply;
 853                 req->response_size = 12 + 4 * length;
 854                 req->response_type = TB_CFG_PKG_READ;
 855
 856                 res = tb_cfg_request_sync(ctl, req, timeout_msec);
 857
 858                 tb_cfg_request_put(req);
 859
 860                 if (res.err != -ETIMEDOUT)
 861                         break;
 862
 863                 /* Wait a bit (arbitrary time) until we send a retry */
 864                 usleep_range(10, 100);
 865         }
 866
 867         if (res.err)
 868                 return res;
 869
 870         res.response_port = reply.addr.port;
 871         res.err = check_config_address(reply.addr, space, offset, length);
 872         if (!res.err)
 873                 memcpy(buffer, &reply.data, 4 * length);
 874         return res;
 875 }
 876
 877 /**
 878  * tb_cfg_write() - write from buffer into config space
 879  *
 880  * Offset and length are in dwords.
 881  */
 882 struct tb_cfg_result tb_cfg_write_raw(struct tb_ctl *ctl, const void *buffer,
 883                 u64 route, u32 port, enum tb_cfg_space space,
 884                 u32 offset, u32 length, int timeout_msec)
 885 {
 886         struct tb_cfg_result res = { 0 };
 887         struct cfg_write_pkg request = {
 888                 .header = tb_cfg_make_header(route),
 889                 .addr = {
 890                         .port = port,
 891                         .space = space,
 892                         .offset = offset,
 893                         .length = length,
 894                 },
 895         };
 896         struct cfg_read_pkg reply;
 897         int retries = 0;
 898
 899         memcpy(&request.data, buffer, length * 4);
 900
 901         while (retries < TB_CTL_RETRIES) {
 902                 struct tb_cfg_request *req;
 903
 904                 req = tb_cfg_request_alloc();
 905                 if (!req) {
 906                         res.err = -ENOMEM;
 907                         return res;
 908                 }
 909
 910                 request.addr.seq = retries++;
 911
 912                 req->match = tb_cfg_match;
 913                 req->copy = tb_cfg_copy;
 914                 req->request = &request;
 915                 req->request_size = 12 + 4 * length;
 916                 req->request_type = TB_CFG_PKG_WRITE;
 917                 req->response = &reply;
 918                 req->response_size = sizeof(reply);
 919                 req->response_type = TB_CFG_PKG_WRITE;
 920
 921                 res = tb_cfg_request_sync(ctl, req, timeout_msec);
 922
 923                 tb_cfg_request_put(req);
 924
 925                 if (res.err != -ETIMEDOUT)
 926                         break;
 927
 928                 /* Wait a bit (arbitrary time) until we send a retry */
 929                 usleep_range(10, 100);
 930         }
 931
 932         if (res.err)
 933                 return res;
 934
 935         res.response_port = reply.addr.port;
 936         res.err = check_config_address(reply.addr, space, offset, length);
 937         return res;
 938 }
 939
 940 static int tb_cfg_get_error(struct tb_ctl *ctl, enum tb_cfg_space space,
 941                             const struct tb_cfg_result *res)
 942 {
 943         /*
 944          * For unimplemented ports access to port config space may return
 945          * TB_CFG_ERROR_INVALID_CONFIG_SPACE (alternatively their type is
 946          * set to TB_TYPE_INACTIVE). In the former case return -ENODEV so
 947          * that the caller can mark the port as disabled.
 948          */
 949         if (space == TB_CFG_PORT &&
 950             res->tb_error == TB_CFG_ERROR_INVALID_CONFIG_SPACE)
 951                 return -ENODEV;
 952
 953         tb_cfg_print_error(ctl, res);
 954         return -EIO;
 955 }
 956
 957 int tb_cfg_read(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
 958                 enum tb_cfg_space space, u32 offset, u32 length)
 959 {
 960         struct tb_cfg_result res = tb_cfg_read_raw(ctl, buffer, route, port,
 961                         space, offset, length, TB_CFG_DEFAULT_TIMEOUT);
 962         switch (res.err) {
 963         case 0:
 964                 /* Success */
 965                 break;
 966
 967         case 1:
 968                 /* Thunderbolt error, tb_error holds the actual number */
 969                 return tb_cfg_get_error(ctl, space, &res);
 970
 971         case -ETIMEDOUT:
 972                 tb_ctl_warn(ctl, "%llx: timeout reading config space %u from %#x\n",
 973                             route, space, offset);
 974                 break;
 975
 976         default:
 977                 WARN(1, "tb_cfg_read: %d\n", res.err);
 978                 break;
 979         }
 980         return res.err;
 981 }
 982
 983 int tb_cfg_write(struct tb_ctl *ctl, const void *buffer, u64 route, u32 port,
 984                  enum tb_cfg_space space, u32 offset, u32 length)
 985 {
 986         struct tb_cfg_result res = tb_cfg_write_raw(ctl, buffer, route, port,
 987                         space, offset, length, TB_CFG_DEFAULT_TIMEOUT);
 988         switch (res.err) {
 989         case 0:
 990                 /* Success */
 991                 break;
 992
 993         case 1:
 994                 /* Thunderbolt error, tb_error holds the actual number */
 995                 return tb_cfg_get_error(ctl, space, &res);
 996
 997         case -ETIMEDOUT:
 998                 tb_ctl_warn(ctl, "%llx: timeout writing config space %u to %#x\n",
 999                             route, space, offset);
1000                 break;
1001
1002         default:
1003                 WARN(1, "tb_cfg_write: %d\n", res.err);
1004                 break;
1005         }
1006         return res.err;
1007 }
1008
1009 /**
1010  * tb_cfg_get_upstream_port() - get upstream port number of switch at route
1011  *
1012  * Reads the first dword from the switches TB_CFG_SWITCH config area and
1013  * returns the port number from which the reply originated.
1014  *
1015  * Return: Returns the upstream port number on success or an error code on
1016  * failure.
1017  */
1018 int tb_cfg_get_upstream_port(struct tb_ctl *ctl, u64 route)
1019 {
1020         u32 dummy;
1021         struct tb_cfg_result res = tb_cfg_read_raw(ctl, &dummy, route, 0,
1022                                                    TB_CFG_SWITCH, 0, 1,
1023                                                    TB_CFG_DEFAULT_TIMEOUT);
1024         if (res.err == 1)
1025                 return -EIO;
1026         if (res.err)
1027                 return res.err;
1028         return res.response_port;
1029 }