drivers/thunderbolt/ctl.c

   1 /*
   2  * Thunderbolt Cactus Ridge driver - control channel and configuration commands
   3  *
   4  * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
   5  */
   6
   7 #include <linux/crc32.h>
   8 #include <linux/slab.h>
   9 #include <linux/pci.h>
  10 #include <linux/dmapool.h>
  11 #include <linux/workqueue.h>
  12 #include <linux/kfifo.h>
  13
  14 #include "ctl.h"
  15
  16
  17 struct ctl_pkg {
  18         struct tb_ctl *ctl;
  19         void *buffer;
  20         struct ring_frame frame;
  21 };
  22
  23 #define TB_CTL_RX_PKG_COUNT 10
  24
  25 /**
  26  * struct tb_cfg - thunderbolt control channel
  27  */
  28 struct tb_ctl {
  29         struct tb_nhi *nhi;
  30         struct tb_ring *tx;
  31         struct tb_ring *rx;
  32
  33         struct dma_pool *frame_pool;
  34         struct ctl_pkg *rx_packets[TB_CTL_RX_PKG_COUNT];
  35         DECLARE_KFIFO(response_fifo, struct ctl_pkg*, 16);
  36         struct completion response_ready;
  37
  38         hotplug_cb callback;
  39         void *callback_data;
  40 };
  41
  42
  43 #define tb_ctl_WARN(ctl, format, arg...) \
  44         dev_WARN(&(ctl)->nhi->pdev->dev, format, ## arg)
  45
  46 #define tb_ctl_err(ctl, format, arg...) \
  47         dev_err(&(ctl)->nhi->pdev->dev, format, ## arg)
  48
  49 #define tb_ctl_warn(ctl, format, arg...) \
  50         dev_warn(&(ctl)->nhi->pdev->dev, format, ## arg)
  51
  52 #define tb_ctl_info(ctl, format, arg...) \
  53         dev_info(&(ctl)->nhi->pdev->dev, format, ## arg)
  54
  55
  56 /* configuration packets definitions */
  57
  58 enum tb_cfg_pkg_type {
  59         TB_CFG_PKG_READ = 1,
  60         TB_CFG_PKG_WRITE = 2,
  61         TB_CFG_PKG_ERROR = 3,
  62         TB_CFG_PKG_NOTIFY_ACK = 4,
  63         TB_CFG_PKG_EVENT = 5,
  64         TB_CFG_PKG_XDOMAIN_REQ = 6,
  65         TB_CFG_PKG_XDOMAIN_RESP = 7,
  66         TB_CFG_PKG_OVERRIDE = 8,
  67         TB_CFG_PKG_RESET = 9,
  68         TB_CFG_PKG_PREPARE_TO_SLEEP = 0xd,
  69 };
  70
  71 /* common header */
  72 struct tb_cfg_header {
  73         u32 route_hi:22;
  74         u32 unknown:10; /* highest order bit is set on replies */
  75         u32 route_lo;
  76 } __packed;
  77
  78 /* additional header for read/write packets */
  79 struct tb_cfg_address {
  80         u32 offset:13; /* in dwords */
  81         u32 length:6; /* in dwords */
  82         u32 port:6;
  83         enum tb_cfg_space space:2;
  84         u32 seq:2; /* sequence number  */
  85         u32 zero:3;
  86 } __packed;
  87
  88 /* TB_CFG_PKG_READ, response for TB_CFG_PKG_WRITE */
  89 struct cfg_read_pkg {
  90         struct tb_cfg_header header;
  91         struct tb_cfg_address addr;
  92 } __packed;
  93
  94 /* TB_CFG_PKG_WRITE, response for TB_CFG_PKG_READ */
  95 struct cfg_write_pkg {
  96         struct tb_cfg_header header;
  97         struct tb_cfg_address addr;
  98         u32 data[64]; /* maximum size, tb_cfg_address.length has 6 bits */
  99 } __packed;
 100
 101 /* TB_CFG_PKG_ERROR */
 102 struct cfg_error_pkg {
 103         struct tb_cfg_header header;
 104         enum tb_cfg_error error:4;
 105         u32 zero1:4;
 106         u32 port:6;
 107         u32 zero2:2; /* Both should be zero, still they are different fields. */
 108         u32 zero3:16;
 109 } __packed;
 110
 111 /* TB_CFG_PKG_EVENT */
 112 struct cfg_event_pkg {
 113         struct tb_cfg_header header;
 114         u32 port:6;
 115         u32 zero:25;
 116         bool unplug:1;
 117 } __packed;
 118
 119 /* TB_CFG_PKG_RESET */
 120 struct cfg_reset_pkg {
 121         struct tb_cfg_header header;
 122 } __packed;
 123
 124 /* TB_CFG_PKG_PREPARE_TO_SLEEP */
 125 struct cfg_pts_pkg {
 126         struct tb_cfg_header header;
 127         u32 data;
 128 } __packed;
 129
 130
 131 /* utility functions */
 132
 133 static u64 get_route(struct tb_cfg_header header)
 134 {
 135         return (u64) header.route_hi << 32 | header.route_lo;
 136 }
 137
 138 static struct tb_cfg_header make_header(u64 route)
 139 {
 140         struct tb_cfg_header header = {
 141                 .route_hi = route >> 32,
 142                 .route_lo = route,
 143         };
 144         /* check for overflow, route_hi is not 32 bits! */
 145         WARN_ON(get_route(header) != route);
 146         return header;
 147 }
 148
 149 static int check_header(struct ctl_pkg *pkg, u32 len, enum tb_cfg_pkg_type type,
 150                         u64 route)
 151 {
 152         struct tb_cfg_header *header = pkg->buffer;
 153
 154         /* check frame, TODO: frame flags */
 155         if (WARN(len != pkg->frame.size,
 156                         "wrong framesize (expected %#x, got %#x)\n",
 157                         len, pkg->frame.size))
 158                 return -EIO;
 159         if (WARN(type != pkg->frame.eof, "wrong eof (expected %#x, got %#x)\n",
 160                         type, pkg->frame.eof))
 161                 return -EIO;
 162         if (WARN(pkg->frame.sof, "wrong sof (expected 0x0, got %#x)\n",
 163                         pkg->frame.sof))
 164                 return -EIO;
 165
 166         /* check header */
 167         if (WARN(header->unknown != 1 << 9,
 168                         "header->unknown is %#x\n", header->unknown))
 169                 return -EIO;
 170         if (WARN(route != get_route(*header),
 171                         "wrong route (expected %llx, got %llx)",
 172                         route, get_route(*header)))
 173                 return -EIO;
 174         return 0;
 175 }
 176
 177 static int check_config_address(struct tb_cfg_address addr,
 178                                 enum tb_cfg_space space, u32 offset,
 179                                 u32 length)
 180 {
 181         if (WARN(addr.zero, "addr.zero is %#x\n", addr.zero))
 182                 return -EIO;
 183         if (WARN(space != addr.space, "wrong space (expected %x, got %x\n)",
 184                         space, addr.space))
 185                 return -EIO;
 186         if (WARN(offset != addr.offset, "wrong offset (expected %x, got %x\n)",
 187                         offset, addr.offset))
 188                 return -EIO;
 189         if (WARN(length != addr.length, "wrong space (expected %x, got %x\n)",
 190                         length, addr.length))
 191                 return -EIO;
 192         if (WARN(addr.seq, "addr.seq is %#x\n", addr.seq))
 193                 return -EIO;
 194         /*
 195          * We cannot check addr->port as it is set to the upstream port of the
 196          * sender.
 197          */
 198         return 0;
 199 }
 200
 201 static struct tb_cfg_result decode_error(struct ctl_pkg *response)
 202 {
 203         struct cfg_error_pkg *pkg = response->buffer;
 204         struct tb_cfg_result res = { 0 };
 205         res.response_route = get_route(pkg->header);
 206         res.response_port = 0;
 207         res.err = check_header(response, sizeof(*pkg), TB_CFG_PKG_ERROR,
 208                                get_route(pkg->header));
 209         if (res.err)
 210                 return res;
 211
 212         WARN(pkg->zero1, "pkg->zero1 is %#x\n", pkg->zero1);
 213         WARN(pkg->zero2, "pkg->zero1 is %#x\n", pkg->zero1);
 214         WARN(pkg->zero3, "pkg->zero1 is %#x\n", pkg->zero1);
 215         res.err = 1;
 216         res.tb_error = pkg->error;
 217         res.response_port = pkg->port;
 218         return res;
 219
 220 }
 221
 222 static struct tb_cfg_result parse_header(struct ctl_pkg *pkg, u32 len,
 223                                          enum tb_cfg_pkg_type type, u64 route)
 224 {
 225         struct tb_cfg_header *header = pkg->buffer;
 226         struct tb_cfg_result res = { 0 };
 227
 228         if (pkg->frame.eof == TB_CFG_PKG_ERROR)
 229                 return decode_error(pkg);
 230
 231         res.response_port = 0; /* will be updated later for cfg_read/write */
 232         res.response_route = get_route(*header);
 233         res.err = check_header(pkg, len, type, route);
 234         return res;
 235 }
 236
 237 static void tb_cfg_print_error(struct tb_ctl *ctl,
 238                                const struct tb_cfg_result *res)
 239 {
 240         WARN_ON(res->err != 1);
 241         switch (res->tb_error) {
 242         case TB_CFG_ERROR_PORT_NOT_CONNECTED:
 243                 /* Port is not connected. This can happen during surprise
 244                  * removal. Do not warn. */
 245                 return;
 246         case TB_CFG_ERROR_INVALID_CONFIG_SPACE:
 247                 /*
 248                  * Invalid cfg_space/offset/length combination in
 249                  * cfg_read/cfg_write.
 250                  */
 251                 tb_ctl_WARN(ctl,
 252                         "CFG_ERROR(%llx:%x): Invalid config space of offset\n",
 253                         res->response_route, res->response_port);
 254                 return;
 255         case TB_CFG_ERROR_NO_SUCH_PORT:
 256                 /*
 257                  * - The route contains a non-existent port.
 258                  * - The route contains a non-PHY port (e.g. PCIe).
 259                  * - The port in cfg_read/cfg_write does not exist.
 260                  */
 261                 tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Invalid port\n",
 262                         res->response_route, res->response_port);
 263                 return;
 264         case TB_CFG_ERROR_LOOP:
 265                 tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Route contains a loop\n",
 266                         res->response_route, res->response_port);
 267                 return;
 268         default:
 269                 /* 5,6,7,9 and 11 are also valid error codes */
 270                 tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Unknown error\n",
 271                         res->response_route, res->response_port);
 272                 return;
 273         }
 274 }
 275
 276 static void cpu_to_be32_array(__be32 *dst, u32 *src, size_t len)
 277 {
 278         int i;
 279         for (i = 0; i < len; i++)
 280                 dst[i] = cpu_to_be32(src[i]);
 281 }
 282
 283 static void be32_to_cpu_array(u32 *dst, __be32 *src, size_t len)
 284 {
 285         int i;
 286         for (i = 0; i < len; i++)
 287                 dst[i] = be32_to_cpu(src[i]);
 288 }
 289
 290 static __be32 tb_crc(void *data, size_t len)
 291 {
 292         return cpu_to_be32(~__crc32c_le(~0, data, len));
 293 }
 294
 295 static void tb_ctl_pkg_free(struct ctl_pkg *pkg)
 296 {
 297         if (pkg) {
 298                 dma_pool_free(pkg->ctl->frame_pool,
 299                               pkg->buffer, pkg->frame.buffer_phy);
 300                 kfree(pkg);
 301         }
 302 }
 303
 304 static struct ctl_pkg *tb_ctl_pkg_alloc(struct tb_ctl *ctl)
 305 {
 306         struct ctl_pkg *pkg = kzalloc(sizeof(*pkg), GFP_KERNEL);
 307         if (!pkg)
 308                 return NULL;
 309         pkg->ctl = ctl;
 310         pkg->buffer = dma_pool_alloc(ctl->frame_pool, GFP_KERNEL,
 311                                      &pkg->frame.buffer_phy);
 312         if (!pkg->buffer) {
 313                 kfree(pkg);
 314                 return NULL;
 315         }
 316         return pkg;
 317 }
 318
 319
 320 /* RX/TX handling */
 321
 322 static void tb_ctl_tx_callback(struct tb_ring *ring, struct ring_frame *frame,
 323                                bool canceled)
 324 {
 325         struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
 326         tb_ctl_pkg_free(pkg);
 327 }
 328
 329 /**
 330  * tb_cfg_tx() - transmit a packet on the control channel
 331  *
 332  * len must be a multiple of four.
 333  *
 334  * Return: Returns 0 on success or an error code on failure.
 335  */
 336 static int tb_ctl_tx(struct tb_ctl *ctl, void *data, size_t len,
 337                      enum tb_cfg_pkg_type type)
 338 {
 339         int res;
 340         struct ctl_pkg *pkg;
 341         if (len % 4 != 0) { /* required for le->be conversion */
 342                 tb_ctl_WARN(ctl, "TX: invalid size: %zu\n", len);
 343                 return -EINVAL;
 344         }
 345         if (len > TB_FRAME_SIZE - 4) { /* checksum is 4 bytes */
 346                 tb_ctl_WARN(ctl, "TX: packet too large: %zu/%d\n",
 347                             len, TB_FRAME_SIZE - 4);
 348                 return -EINVAL;
 349         }
 350         pkg = tb_ctl_pkg_alloc(ctl);
 351         if (!pkg)
 352                 return -ENOMEM;
 353         pkg->frame.callback = tb_ctl_tx_callback;
 354         pkg->frame.size = len + 4;
 355         pkg->frame.sof = type;
 356         pkg->frame.eof = type;
 357         cpu_to_be32_array(pkg->buffer, data, len / 4);
 358         *(__be32 *) (pkg->buffer + len) = tb_crc(pkg->buffer, len);
 359
 360         res = ring_tx(ctl->tx, &pkg->frame);
 361         if (res) /* ring is stopped */
 362                 tb_ctl_pkg_free(pkg);
 363         return res;
 364 }
 365
 366 /**
 367  * tb_ctl_handle_plug_event() - acknowledge a plug event, invoke ctl->callback
 368  */
 369 static void tb_ctl_handle_plug_event(struct tb_ctl *ctl,
 370                                      struct ctl_pkg *response)
 371 {
 372         struct cfg_event_pkg *pkg = response->buffer;
 373         u64 route = get_route(pkg->header);
 374
 375         if (check_header(response, sizeof(*pkg), TB_CFG_PKG_EVENT, route)) {
 376                 tb_ctl_warn(ctl, "malformed TB_CFG_PKG_EVENT\n");
 377                 return;
 378         }
 379
 380         if (tb_cfg_error(ctl, route, pkg->port, TB_CFG_ERROR_ACK_PLUG_EVENT))
 381                 tb_ctl_warn(ctl, "could not ack plug event on %llx:%x\n",
 382                             route, pkg->port);
 383         WARN(pkg->zero, "pkg->zero is %#x\n", pkg->zero);
 384         ctl->callback(ctl->callback_data, route, pkg->port, pkg->unplug);
 385 }
 386
 387 static void tb_ctl_rx_submit(struct ctl_pkg *pkg)
 388 {
 389         ring_rx(pkg->ctl->rx, &pkg->frame); /*
 390                                              * We ignore failures during stop.
 391                                              * All rx packets are referenced
 392                                              * from ctl->rx_packets, so we do
 393                                              * not loose them.
 394                                              */
 395 }
 396
 397 static void tb_ctl_rx_callback(struct tb_ring *ring, struct ring_frame *frame,
 398                                bool canceled)
 399 {
 400         struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
 401
 402         if (canceled)
 403                 return; /*
 404                          * ring is stopped, packet is referenced from
 405                          * ctl->rx_packets.
 406                          */
 407
 408         if (frame->size < 4 || frame->size % 4 != 0) {
 409                 tb_ctl_err(pkg->ctl, "RX: invalid size %#x, dropping packet\n",
 410                            frame->size);
 411                 goto rx;
 412         }
 413
 414         frame->size -= 4; /* remove checksum */
 415         if (*(__be32 *) (pkg->buffer + frame->size)
 416                         != tb_crc(pkg->buffer, frame->size)) {
 417                 tb_ctl_err(pkg->ctl,
 418                            "RX: checksum mismatch, dropping packet\n");
 419                 goto rx;
 420         }
 421         be32_to_cpu_array(pkg->buffer, pkg->buffer, frame->size / 4);
 422
 423         if (frame->eof == TB_CFG_PKG_EVENT) {
 424                 tb_ctl_handle_plug_event(pkg->ctl, pkg);
 425                 goto rx;
 426         }
 427         if (!kfifo_put(&pkg->ctl->response_fifo, pkg)) {
 428                 tb_ctl_err(pkg->ctl, "RX: fifo is full\n");
 429                 goto rx;
 430         }
 431         complete(&pkg->ctl->response_ready);
 432         return;
 433 rx:
 434         tb_ctl_rx_submit(pkg);
 435 }
 436
 437 /**
 438  * tb_ctl_rx() - receive a packet from the control channel
 439  */
 440 static struct tb_cfg_result tb_ctl_rx(struct tb_ctl *ctl, void *buffer,
 441                                       size_t length, int timeout_msec,
 442                                       u64 route, enum tb_cfg_pkg_type type)
 443 {
 444         struct tb_cfg_result res;
 445         struct ctl_pkg *pkg;
 446
 447         if (!wait_for_completion_timeout(&ctl->response_ready,
 448                                          msecs_to_jiffies(timeout_msec))) {
 449                 tb_ctl_WARN(ctl, "RX: timeout\n");
 450                 return (struct tb_cfg_result) { .err = -ETIMEDOUT };
 451         }
 452         if (!kfifo_get(&ctl->response_fifo, &pkg)) {
 453                 tb_ctl_WARN(ctl, "empty kfifo\n");
 454                 return (struct tb_cfg_result) { .err = -EIO };
 455         }
 456
 457         res = parse_header(pkg, length, type, route);
 458         if (!res.err)
 459                 memcpy(buffer, pkg->buffer, length);
 460         tb_ctl_rx_submit(pkg);
 461         return res;
 462 }
 463
 464
 465 /* public interface, alloc/start/stop/free */
 466
 467 /**
 468  * tb_ctl_alloc() - allocate a control channel
 469  *
 470  * cb will be invoked once for every hot plug event.
 471  *
 472  * Return: Returns a pointer on success or NULL on failure.
 473  */
 474 struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, hotplug_cb cb, void *cb_data)
 475 {
 476         int i;
 477         struct tb_ctl *ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
 478         if (!ctl)
 479                 return NULL;
 480         ctl->nhi = nhi;
 481         ctl->callback = cb;
 482         ctl->callback_data = cb_data;
 483
 484         init_completion(&ctl->response_ready);
 485         INIT_KFIFO(ctl->response_fifo);
 486         ctl->frame_pool = dma_pool_create("thunderbolt_ctl", &nhi->pdev->dev,
 487                                          TB_FRAME_SIZE, 4, 0);
 488         if (!ctl->frame_pool)
 489                 goto err;
 490
 491         ctl->tx = ring_alloc_tx(nhi, 0, 10);
 492         if (!ctl->tx)
 493                 goto err;
 494
 495         ctl->rx = ring_alloc_rx(nhi, 0, 10);
 496         if (!ctl->rx)
 497                 goto err;
 498
 499         for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++) {
 500                 ctl->rx_packets[i] = tb_ctl_pkg_alloc(ctl);
 501                 if (!ctl->rx_packets[i])
 502                         goto err;
 503                 ctl->rx_packets[i]->frame.callback = tb_ctl_rx_callback;
 504         }
 505
 506         tb_ctl_info(ctl, "control channel created\n");
 507         return ctl;
 508 err:
 509         tb_ctl_free(ctl);
 510         return NULL;
 511 }
 512
 513 /**
 514  * tb_ctl_free() - free a control channel
 515  *
 516  * Must be called after tb_ctl_stop.
 517  *
 518  * Must NOT be called from ctl->callback.
 519  */
 520 void tb_ctl_free(struct tb_ctl *ctl)
 521 {
 522         int i;
 523         if (ctl->rx)
 524                 ring_free(ctl->rx);
 525         if (ctl->tx)
 526                 ring_free(ctl->tx);
 527
 528         /* free RX packets */
 529         for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
 530                 tb_ctl_pkg_free(ctl->rx_packets[i]);
 531
 532
 533         if (ctl->frame_pool)
 534                 dma_pool_destroy(ctl->frame_pool);
 535         kfree(ctl);
 536 }
 537
 538 /**
 539  * tb_cfg_start() - start/resume the control channel
 540  */
 541 void tb_ctl_start(struct tb_ctl *ctl)
 542 {
 543         int i;
 544         tb_ctl_info(ctl, "control channel starting...\n");
 545         ring_start(ctl->tx); /* is used to ack hotplug packets, start first */
 546         ring_start(ctl->rx);
 547         for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
 548                 tb_ctl_rx_submit(ctl->rx_packets[i]);
 549 }
 550
 551 /**
 552  * control() - pause the control channel
 553  *
 554  * All invocations of ctl->callback will have finished after this method
 555  * returns.
 556  *
 557  * Must NOT be called from ctl->callback.
 558  */
 559 void tb_ctl_stop(struct tb_ctl *ctl)
 560 {
 561         ring_stop(ctl->rx);
 562         ring_stop(ctl->tx);
 563
 564         if (!kfifo_is_empty(&ctl->response_fifo))
 565                 tb_ctl_WARN(ctl, "dangling response in response_fifo\n");
 566         kfifo_reset(&ctl->response_fifo);
 567         tb_ctl_info(ctl, "control channel stopped\n");
 568 }
 569
 570 /* public interface, commands */
 571
 572 /**
 573  * tb_cfg_error() - send error packet
 574  *
 575  * Return: Returns 0 on success or an error code on failure.
 576  */
 577 int tb_cfg_error(struct tb_ctl *ctl, u64 route, u32 port,
 578                  enum tb_cfg_error error)
 579 {
 580         struct cfg_error_pkg pkg = {
 581                 .header = make_header(route),
 582                 .port = port,
 583                 .error = error,
 584         };
 585         tb_ctl_info(ctl, "resetting error on %llx:%x.\n", route, port);
 586         return tb_ctl_tx(ctl, &pkg, sizeof(pkg), TB_CFG_PKG_ERROR);
 587 }
 588
 589 /**
 590  * tb_cfg_reset() - send a reset packet and wait for a response
 591  *
 592  * If the switch at route is incorrectly configured then we will not receive a
 593  * reply (even though the switch will reset). The caller should check for
 594  * -ETIMEDOUT and attempt to reconfigure the switch.
 595  */
 596 struct tb_cfg_result tb_cfg_reset(struct tb_ctl *ctl, u64 route,
 597                                   int timeout_msec)
 598 {
 599         int err;
 600         struct cfg_reset_pkg request = { .header = make_header(route) };
 601         struct tb_cfg_header reply;
 602
 603         err = tb_ctl_tx(ctl, &request, sizeof(request), TB_CFG_PKG_RESET);
 604         if (err)
 605                 return (struct tb_cfg_result) { .err = err };
 606
 607         return tb_ctl_rx(ctl, &reply, sizeof(reply), timeout_msec, route,
 608                          TB_CFG_PKG_RESET);
 609 }
 610
 611 /**
 612  * tb_cfg_read() - read from config space into buffer
 613  *
 614  * Offset and length are in dwords.
 615  */
 616 struct tb_cfg_result tb_cfg_read_raw(struct tb_ctl *ctl, void *buffer,
 617                 u64 route, u32 port, enum tb_cfg_space space,
 618                 u32 offset, u32 length, int timeout_msec)
 619 {
 620         struct tb_cfg_result res = { 0 };
 621         struct cfg_read_pkg request = {
 622                 .header = make_header(route),
 623                 .addr = {
 624                         .port = port,
 625                         .space = space,
 626                         .offset = offset,
 627                         .length = length,
 628                 },
 629         };
 630         struct cfg_write_pkg reply;
 631
 632         res.err = tb_ctl_tx(ctl, &request, sizeof(request), TB_CFG_PKG_READ);
 633         if (res.err)
 634                 return res;
 635
 636         res = tb_ctl_rx(ctl, &reply, 12 + 4 * length, timeout_msec, route,
 637                         TB_CFG_PKG_READ);
 638         if (res.err)
 639                 return res;
 640
 641         res.response_port = reply.addr.port;
 642         res.err = check_config_address(reply.addr, space, offset, length);
 643         if (!res.err)
 644                 memcpy(buffer, &reply.data, 4 * length);
 645         return res;
 646 }
 647
 648 /**
 649  * tb_cfg_write() - write from buffer into config space
 650  *
 651  * Offset and length are in dwords.
 652  */
 653 struct tb_cfg_result tb_cfg_write_raw(struct tb_ctl *ctl, void *buffer,
 654                 u64 route, u32 port, enum tb_cfg_space space,
 655                 u32 offset, u32 length, int timeout_msec)
 656 {
 657         struct tb_cfg_result res = { 0 };
 658         struct cfg_write_pkg request = {
 659                 .header = make_header(route),
 660                 .addr = {
 661                         .port = port,
 662                         .space = space,
 663                         .offset = offset,
 664                         .length = length,
 665                 },
 666         };
 667         struct cfg_read_pkg reply;
 668
 669         memcpy(&request.data, buffer, length * 4);
 670
 671         res.err = tb_ctl_tx(ctl, &request, 12 + 4 * length, TB_CFG_PKG_WRITE);
 672         if (res.err)
 673                 return res;
 674
 675         res = tb_ctl_rx(ctl, &reply, sizeof(reply), timeout_msec, route,
 676                         TB_CFG_PKG_WRITE);
 677         if (res.err)
 678                 return res;
 679
 680         res.response_port = reply.addr.port;
 681         res.err = check_config_address(reply.addr, space, offset, length);
 682         return res;
 683 }
 684
 685 int tb_cfg_read(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
 686                 enum tb_cfg_space space, u32 offset, u32 length)
 687 {
 688         struct tb_cfg_result res = tb_cfg_read_raw(ctl, buffer, route, port,
 689                         space, offset, length, TB_CFG_DEFAULT_TIMEOUT);
 690         if (res.err == 1) {
 691                 tb_cfg_print_error(ctl, &res);
 692                 return -EIO;
 693         }
 694         WARN(res.err, "tb_cfg_read: %d\n", res.err);
 695         return res.err;
 696 }
 697
 698 int tb_cfg_write(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
 699                  enum tb_cfg_space space, u32 offset, u32 length)
 700 {
 701         struct tb_cfg_result res = tb_cfg_write_raw(ctl, buffer, route, port,
 702                         space, offset, length, TB_CFG_DEFAULT_TIMEOUT);
 703         if (res.err == 1) {
 704                 tb_cfg_print_error(ctl, &res);
 705                 return -EIO;
 706         }
 707         WARN(res.err, "tb_cfg_write: %d\n", res.err);
 708         return res.err;
 709 }
 710
 711 /**
 712  * tb_cfg_get_upstream_port() - get upstream port number of switch at route
 713  *
 714  * Reads the first dword from the switches TB_CFG_SWITCH config area and
 715  * returns the port number from which the reply originated.
 716  *
 717  * Return: Returns the upstream port number on success or an error code on
 718  * failure.
 719  */
 720 int tb_cfg_get_upstream_port(struct tb_ctl *ctl, u64 route)
 721 {
 722         u32 dummy;
 723         struct tb_cfg_result res = tb_cfg_read_raw(ctl, &dummy, route, 0,
 724                                                    TB_CFG_SWITCH, 0, 1,
 725                                                    TB_CFG_DEFAULT_TIMEOUT);
 726         if (res.err == 1)
 727                 return -EIO;
 728         if (res.err)
 729                 return res.err;
 730         return res.response_port;
 731 }