drivers/thunderbolt/tunnel.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Thunderbolt driver - Tunneling support
   4  *
   5  * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
   6  * Copyright (C) 2019, Intel Corporation
   7  */
   8
   9 #include <linux/delay.h>
  10 #include <linux/slab.h>
  11 #include <linux/list.h>
  12
  13 #include "tunnel.h"
  14 #include "tb.h"
  15
  16 /* PCIe adapters use always HopID of 8 for both directions */
  17 #define TB_PCI_HOPID                    8
  18
  19 #define TB_PCI_PATH_DOWN                0
  20 #define TB_PCI_PATH_UP                  1
  21
  22 /* USB3 adapters use always HopID of 8 for both directions */
  23 #define TB_USB3_HOPID                   8
  24
  25 #define TB_USB3_PATH_DOWN               0
  26 #define TB_USB3_PATH_UP                 1
  27
  28 /* DP adapters use HopID 8 for AUX and 9 for Video */
  29 #define TB_DP_AUX_TX_HOPID              8
  30 #define TB_DP_AUX_RX_HOPID              8
  31 #define TB_DP_VIDEO_HOPID               9
  32
  33 #define TB_DP_VIDEO_PATH_OUT            0
  34 #define TB_DP_AUX_PATH_OUT              1
  35 #define TB_DP_AUX_PATH_IN               2
  36
  37 #define TB_DMA_PATH_OUT                 0
  38 #define TB_DMA_PATH_IN                  1
  39
  40 static const char * const tb_tunnel_names[] = { "PCI", "DP", "DMA", "USB3" };
  41
  42 #define __TB_TUNNEL_PRINT(level, tunnel, fmt, arg...)                   \
  43         do {                                                            \
  44                 struct tb_tunnel *__tunnel = (tunnel);                  \
  45                 level(__tunnel->tb, "%llx:%x <-> %llx:%x (%s): " fmt,   \
  46                       tb_route(__tunnel->src_port->sw),                 \
  47                       __tunnel->src_port->port,                         \
  48                       tb_route(__tunnel->dst_port->sw),                 \
  49                       __tunnel->dst_port->port,                         \
  50                       tb_tunnel_names[__tunnel->type],                  \
  51                       ## arg);                                          \
  52         } while (0)
  53
  54 #define tb_tunnel_WARN(tunnel, fmt, arg...) \
  55         __TB_TUNNEL_PRINT(tb_WARN, tunnel, fmt, ##arg)
  56 #define tb_tunnel_warn(tunnel, fmt, arg...) \
  57         __TB_TUNNEL_PRINT(tb_warn, tunnel, fmt, ##arg)
  58 #define tb_tunnel_info(tunnel, fmt, arg...) \
  59         __TB_TUNNEL_PRINT(tb_info, tunnel, fmt, ##arg)
  60 #define tb_tunnel_dbg(tunnel, fmt, arg...) \
  61         __TB_TUNNEL_PRINT(tb_dbg, tunnel, fmt, ##arg)
  62
  63 static struct tb_tunnel *tb_tunnel_alloc(struct tb *tb, size_t npaths,
  64                                          enum tb_tunnel_type type)
  65 {
  66         struct tb_tunnel *tunnel;
  67
  68         tunnel = kzalloc(sizeof(*tunnel), GFP_KERNEL);
  69         if (!tunnel)
  70                 return NULL;
  71
  72         tunnel->paths = kcalloc(npaths, sizeof(tunnel->paths[0]), GFP_KERNEL);
  73         if (!tunnel->paths) {
  74                 tb_tunnel_free(tunnel);
  75                 return NULL;
  76         }
  77
  78         INIT_LIST_HEAD(&tunnel->list);
  79         tunnel->tb = tb;
  80         tunnel->npaths = npaths;
  81         tunnel->type = type;
  82
  83         return tunnel;
  84 }
  85
  86 static int tb_pci_activate(struct tb_tunnel *tunnel, bool activate)
  87 {
  88         int res;
  89
  90         res = tb_pci_port_enable(tunnel->src_port, activate);
  91         if (res)
  92                 return res;
  93
  94         if (tb_port_is_pcie_up(tunnel->dst_port))
  95                 return tb_pci_port_enable(tunnel->dst_port, activate);
  96
  97         return 0;
  98 }
  99
 100 static int tb_initial_credits(const struct tb_switch *sw)
 101 {
 102         /* If the path is complete sw is not NULL */
 103         if (sw) {
 104                 /* More credits for faster link */
 105                 switch (sw->link_speed * sw->link_width) {
 106                 case 40:
 107                         return 32;
 108                 case 20:
 109                         return 24;
 110                 }
 111         }
 112
 113         return 16;
 114 }
 115
 116 static void tb_pci_init_path(struct tb_path *path)
 117 {
 118         path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
 119         path->egress_shared_buffer = TB_PATH_NONE;
 120         path->ingress_fc_enable = TB_PATH_ALL;
 121         path->ingress_shared_buffer = TB_PATH_NONE;
 122         path->priority = 3;
 123         path->weight = 1;
 124         path->drop_packages = 0;
 125         path->nfc_credits = 0;
 126         path->hops[0].initial_credits = 7;
 127         path->hops[1].initial_credits =
 128                 tb_initial_credits(path->hops[1].in_port->sw);
 129 }
 130
 131 /**
 132  * tb_tunnel_discover_pci() - Discover existing PCIe tunnels
 133  * @tb: Pointer to the domain structure
 134  * @down: PCIe downstream adapter
 135  *
 136  * If @down adapter is active, follows the tunnel to the PCIe upstream
 137  * adapter and back. Returns the discovered tunnel or %NULL if there was
 138  * no tunnel.
 139  */
 140 struct tb_tunnel *tb_tunnel_discover_pci(struct tb *tb, struct tb_port *down)
 141 {
 142         struct tb_tunnel *tunnel;
 143         struct tb_path *path;
 144
 145         if (!tb_pci_port_is_enabled(down))
 146                 return NULL;
 147
 148         tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_PCI);
 149         if (!tunnel)
 150                 return NULL;
 151
 152         tunnel->activate = tb_pci_activate;
 153         tunnel->src_port = down;
 154
 155         /*
 156          * Discover both paths even if they are not complete. We will
 157          * clean them up by calling tb_tunnel_deactivate() below in that
 158          * case.
 159          */
 160         path = tb_path_discover(down, TB_PCI_HOPID, NULL, -1,
 161                                 &tunnel->dst_port, "PCIe Up");
 162         if (!path) {
 163                 /* Just disable the downstream port */
 164                 tb_pci_port_enable(down, false);
 165                 goto err_free;
 166         }
 167         tunnel->paths[TB_PCI_PATH_UP] = path;
 168         tb_pci_init_path(tunnel->paths[TB_PCI_PATH_UP]);
 169
 170         path = tb_path_discover(tunnel->dst_port, -1, down, TB_PCI_HOPID, NULL,
 171                                 "PCIe Down");
 172         if (!path)
 173                 goto err_deactivate;
 174         tunnel->paths[TB_PCI_PATH_DOWN] = path;
 175         tb_pci_init_path(tunnel->paths[TB_PCI_PATH_DOWN]);
 176
 177         /* Validate that the tunnel is complete */
 178         if (!tb_port_is_pcie_up(tunnel->dst_port)) {
 179                 tb_port_warn(tunnel->dst_port,
 180                              "path does not end on a PCIe adapter, cleaning up\n");
 181                 goto err_deactivate;
 182         }
 183
 184         if (down != tunnel->src_port) {
 185                 tb_tunnel_warn(tunnel, "path is not complete, cleaning up\n");
 186                 goto err_deactivate;
 187         }
 188
 189         if (!tb_pci_port_is_enabled(tunnel->dst_port)) {
 190                 tb_tunnel_warn(tunnel,
 191                                "tunnel is not fully activated, cleaning up\n");
 192                 goto err_deactivate;
 193         }
 194
 195         tb_tunnel_dbg(tunnel, "discovered\n");
 196         return tunnel;
 197
 198 err_deactivate:
 199         tb_tunnel_deactivate(tunnel);
 200 err_free:
 201         tb_tunnel_free(tunnel);
 202
 203         return NULL;
 204 }
 205
 206 /**
 207  * tb_tunnel_alloc_pci() - allocate a pci tunnel
 208  * @tb: Pointer to the domain structure
 209  * @up: PCIe upstream adapter port
 210  * @down: PCIe downstream adapter port
 211  *
 212  * Allocate a PCI tunnel. The ports must be of type TB_TYPE_PCIE_UP and
 213  * TB_TYPE_PCIE_DOWN.
 214  *
 215  * Return: Returns a tb_tunnel on success or NULL on failure.
 216  */
 217 struct tb_tunnel *tb_tunnel_alloc_pci(struct tb *tb, struct tb_port *up,
 218                                       struct tb_port *down)
 219 {
 220         struct tb_tunnel *tunnel;
 221         struct tb_path *path;
 222
 223         tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_PCI);
 224         if (!tunnel)
 225                 return NULL;
 226
 227         tunnel->activate = tb_pci_activate;
 228         tunnel->src_port = down;
 229         tunnel->dst_port = up;
 230
 231         path = tb_path_alloc(tb, down, TB_PCI_HOPID, up, TB_PCI_HOPID, 0,
 232                              "PCIe Down");
 233         if (!path) {
 234                 tb_tunnel_free(tunnel);
 235                 return NULL;
 236         }
 237         tb_pci_init_path(path);
 238         tunnel->paths[TB_PCI_PATH_DOWN] = path;
 239
 240         path = tb_path_alloc(tb, up, TB_PCI_HOPID, down, TB_PCI_HOPID, 0,
 241                              "PCIe Up");
 242         if (!path) {
 243                 tb_tunnel_free(tunnel);
 244                 return NULL;
 245         }
 246         tb_pci_init_path(path);
 247         tunnel->paths[TB_PCI_PATH_UP] = path;
 248
 249         return tunnel;
 250 }
 251
 252 static bool tb_dp_is_usb4(const struct tb_switch *sw)
 253 {
 254         /* Titan Ridge DP adapters need the same treatment as USB4 */
 255         return tb_switch_is_usb4(sw) || tb_switch_is_titan_ridge(sw);
 256 }
 257
 258 static int tb_dp_cm_handshake(struct tb_port *in, struct tb_port *out)
 259 {
 260         int timeout = 10;
 261         u32 val;
 262         int ret;
 263
 264         /* Both ends need to support this */
 265         if (!tb_dp_is_usb4(in->sw) || !tb_dp_is_usb4(out->sw))
 266                 return 0;
 267
 268         ret = tb_port_read(out, &val, TB_CFG_PORT,
 269                            out->cap_adap + DP_STATUS_CTRL, 1);
 270         if (ret)
 271                 return ret;
 272
 273         val |= DP_STATUS_CTRL_UF | DP_STATUS_CTRL_CMHS;
 274
 275         ret = tb_port_write(out, &val, TB_CFG_PORT,
 276                             out->cap_adap + DP_STATUS_CTRL, 1);
 277         if (ret)
 278                 return ret;
 279
 280         do {
 281                 ret = tb_port_read(out, &val, TB_CFG_PORT,
 282                                    out->cap_adap + DP_STATUS_CTRL, 1);
 283                 if (ret)
 284                         return ret;
 285                 if (!(val & DP_STATUS_CTRL_CMHS))
 286                         return 0;
 287                 usleep_range(10, 100);
 288         } while (timeout--);
 289
 290         return -ETIMEDOUT;
 291 }
 292
 293 static inline u32 tb_dp_cap_get_rate(u32 val)
 294 {
 295         u32 rate = (val & DP_COMMON_CAP_RATE_MASK) >> DP_COMMON_CAP_RATE_SHIFT;
 296
 297         switch (rate) {
 298         case DP_COMMON_CAP_RATE_RBR:
 299                 return 1620;
 300         case DP_COMMON_CAP_RATE_HBR:
 301                 return 2700;
 302         case DP_COMMON_CAP_RATE_HBR2:
 303                 return 5400;
 304         case DP_COMMON_CAP_RATE_HBR3:
 305                 return 8100;
 306         default:
 307                 return 0;
 308         }
 309 }
 310
 311 static inline u32 tb_dp_cap_set_rate(u32 val, u32 rate)
 312 {
 313         val &= ~DP_COMMON_CAP_RATE_MASK;
 314         switch (rate) {
 315         default:
 316                 WARN(1, "invalid rate %u passed, defaulting to 1620 MB/s\n", rate);
 317                 /* Fallthrough */
 318         case 1620:
 319                 val |= DP_COMMON_CAP_RATE_RBR << DP_COMMON_CAP_RATE_SHIFT;
 320                 break;
 321         case 2700:
 322                 val |= DP_COMMON_CAP_RATE_HBR << DP_COMMON_CAP_RATE_SHIFT;
 323                 break;
 324         case 5400:
 325                 val |= DP_COMMON_CAP_RATE_HBR2 << DP_COMMON_CAP_RATE_SHIFT;
 326                 break;
 327         case 8100:
 328                 val |= DP_COMMON_CAP_RATE_HBR3 << DP_COMMON_CAP_RATE_SHIFT;
 329                 break;
 330         }
 331         return val;
 332 }
 333
 334 static inline u32 tb_dp_cap_get_lanes(u32 val)
 335 {
 336         u32 lanes = (val & DP_COMMON_CAP_LANES_MASK) >> DP_COMMON_CAP_LANES_SHIFT;
 337
 338         switch (lanes) {
 339         case DP_COMMON_CAP_1_LANE:
 340                 return 1;
 341         case DP_COMMON_CAP_2_LANES:
 342                 return 2;
 343         case DP_COMMON_CAP_4_LANES:
 344                 return 4;
 345         default:
 346                 return 0;
 347         }
 348 }
 349
 350 static inline u32 tb_dp_cap_set_lanes(u32 val, u32 lanes)
 351 {
 352         val &= ~DP_COMMON_CAP_LANES_MASK;
 353         switch (lanes) {
 354         default:
 355                 WARN(1, "invalid number of lanes %u passed, defaulting to 1\n",
 356                      lanes);
 357                 /* Fallthrough */
 358         case 1:
 359                 val |= DP_COMMON_CAP_1_LANE << DP_COMMON_CAP_LANES_SHIFT;
 360                 break;
 361         case 2:
 362                 val |= DP_COMMON_CAP_2_LANES << DP_COMMON_CAP_LANES_SHIFT;
 363                 break;
 364         case 4:
 365                 val |= DP_COMMON_CAP_4_LANES << DP_COMMON_CAP_LANES_SHIFT;
 366                 break;
 367         }
 368         return val;
 369 }
 370
 371 static unsigned int tb_dp_bandwidth(unsigned int rate, unsigned int lanes)
 372 {
 373         /* Tunneling removes the DP 8b/10b encoding */
 374         return rate * lanes * 8 / 10;
 375 }
 376
 377 static int tb_dp_reduce_bandwidth(int max_bw, u32 in_rate, u32 in_lanes,
 378                                   u32 out_rate, u32 out_lanes, u32 *new_rate,
 379                                   u32 *new_lanes)
 380 {
 381         static const u32 dp_bw[][2] = {
 382                 /* Mb/s, lanes */
 383                 { 8100, 4 }, /* 25920 Mb/s */
 384                 { 5400, 4 }, /* 17280 Mb/s */
 385                 { 8100, 2 }, /* 12960 Mb/s */
 386                 { 2700, 4 }, /* 8640 Mb/s */
 387                 { 5400, 2 }, /* 8640 Mb/s */
 388                 { 8100, 1 }, /* 6480 Mb/s */
 389                 { 1620, 4 }, /* 5184 Mb/s */
 390                 { 5400, 1 }, /* 4320 Mb/s */
 391                 { 2700, 2 }, /* 4320 Mb/s */
 392                 { 1620, 2 }, /* 2592 Mb/s */
 393                 { 2700, 1 }, /* 2160 Mb/s */
 394                 { 1620, 1 }, /* 1296 Mb/s */
 395         };
 396         unsigned int i;
 397
 398         /*
 399          * Find a combination that can fit into max_bw and does not
 400          * exceed the maximum rate and lanes supported by the DP OUT and
 401          * DP IN adapters.
 402          */
 403         for (i = 0; i < ARRAY_SIZE(dp_bw); i++) {
 404                 if (dp_bw[i][0] > out_rate || dp_bw[i][1] > out_lanes)
 405                         continue;
 406
 407                 if (dp_bw[i][0] > in_rate || dp_bw[i][1] > in_lanes)
 408                         continue;
 409
 410                 if (tb_dp_bandwidth(dp_bw[i][0], dp_bw[i][1]) <= max_bw) {
 411                         *new_rate = dp_bw[i][0];
 412                         *new_lanes = dp_bw[i][1];
 413                         return 0;
 414                 }
 415         }
 416
 417         return -ENOSR;
 418 }
 419
 420 static int tb_dp_xchg_caps(struct tb_tunnel *tunnel)
 421 {
 422         u32 out_dp_cap, out_rate, out_lanes, in_dp_cap, in_rate, in_lanes, bw;
 423         struct tb_port *out = tunnel->dst_port;
 424         struct tb_port *in = tunnel->src_port;
 425         int ret;
 426
 427         /*
 428          * Copy DP_LOCAL_CAP register to DP_REMOTE_CAP register for
 429          * newer generation hardware.
 430          */
 431         if (in->sw->generation < 2 || out->sw->generation < 2)
 432                 return 0;
 433
 434         /*
 435          * Perform connection manager handshake between IN and OUT ports
 436          * before capabilities exchange can take place.
 437          */
 438         ret = tb_dp_cm_handshake(in, out);
 439         if (ret)
 440                 return ret;
 441
 442         /* Read both DP_LOCAL_CAP registers */
 443         ret = tb_port_read(in, &in_dp_cap, TB_CFG_PORT,
 444                            in->cap_adap + DP_LOCAL_CAP, 1);
 445         if (ret)
 446                 return ret;
 447
 448         ret = tb_port_read(out, &out_dp_cap, TB_CFG_PORT,
 449                            out->cap_adap + DP_LOCAL_CAP, 1);
 450         if (ret)
 451                 return ret;
 452
 453         /* Write IN local caps to OUT remote caps */
 454         ret = tb_port_write(out, &in_dp_cap, TB_CFG_PORT,
 455                             out->cap_adap + DP_REMOTE_CAP, 1);
 456         if (ret)
 457                 return ret;
 458
 459         in_rate = tb_dp_cap_get_rate(in_dp_cap);
 460         in_lanes = tb_dp_cap_get_lanes(in_dp_cap);
 461         tb_port_dbg(in, "maximum supported bandwidth %u Mb/s x%u = %u Mb/s\n",
 462                     in_rate, in_lanes, tb_dp_bandwidth(in_rate, in_lanes));
 463
 464         /*
 465          * If the tunnel bandwidth is limited (max_bw is set) then see
 466          * if we need to reduce bandwidth to fit there.
 467          */
 468         out_rate = tb_dp_cap_get_rate(out_dp_cap);
 469         out_lanes = tb_dp_cap_get_lanes(out_dp_cap);
 470         bw = tb_dp_bandwidth(out_rate, out_lanes);
 471         tb_port_dbg(out, "maximum supported bandwidth %u Mb/s x%u = %u Mb/s\n",
 472                     out_rate, out_lanes, bw);
 473
 474         if (tunnel->max_bw && bw > tunnel->max_bw) {
 475                 u32 new_rate, new_lanes, new_bw;
 476
 477                 ret = tb_dp_reduce_bandwidth(tunnel->max_bw, in_rate, in_lanes,
 478                                              out_rate, out_lanes, &new_rate,
 479                                              &new_lanes);
 480                 if (ret) {
 481                         tb_port_info(out, "not enough bandwidth for DP tunnel\n");
 482                         return ret;
 483                 }
 484
 485                 new_bw = tb_dp_bandwidth(new_rate, new_lanes);
 486                 tb_port_dbg(out, "bandwidth reduced to %u Mb/s x%u = %u Mb/s\n",
 487                             new_rate, new_lanes, new_bw);
 488
 489                 /*
 490                  * Set new rate and number of lanes before writing it to
 491                  * the IN port remote caps.
 492                  */
 493                 out_dp_cap = tb_dp_cap_set_rate(out_dp_cap, new_rate);
 494                 out_dp_cap = tb_dp_cap_set_lanes(out_dp_cap, new_lanes);
 495         }
 496
 497         return tb_port_write(in, &out_dp_cap, TB_CFG_PORT,
 498                              in->cap_adap + DP_REMOTE_CAP, 1);
 499 }
 500
 501 static int tb_dp_activate(struct tb_tunnel *tunnel, bool active)
 502 {
 503         int ret;
 504
 505         if (active) {
 506                 struct tb_path **paths;
 507                 int last;
 508
 509                 paths = tunnel->paths;
 510                 last = paths[TB_DP_VIDEO_PATH_OUT]->path_length - 1;
 511
 512                 tb_dp_port_set_hops(tunnel->src_port,
 513                         paths[TB_DP_VIDEO_PATH_OUT]->hops[0].in_hop_index,
 514                         paths[TB_DP_AUX_PATH_OUT]->hops[0].in_hop_index,
 515                         paths[TB_DP_AUX_PATH_IN]->hops[last].next_hop_index);
 516
 517                 tb_dp_port_set_hops(tunnel->dst_port,
 518                         paths[TB_DP_VIDEO_PATH_OUT]->hops[last].next_hop_index,
 519                         paths[TB_DP_AUX_PATH_IN]->hops[0].in_hop_index,
 520                         paths[TB_DP_AUX_PATH_OUT]->hops[last].next_hop_index);
 521         } else {
 522                 tb_dp_port_hpd_clear(tunnel->src_port);
 523                 tb_dp_port_set_hops(tunnel->src_port, 0, 0, 0);
 524                 if (tb_port_is_dpout(tunnel->dst_port))
 525                         tb_dp_port_set_hops(tunnel->dst_port, 0, 0, 0);
 526         }
 527
 528         ret = tb_dp_port_enable(tunnel->src_port, active);
 529         if (ret)
 530                 return ret;
 531
 532         if (tb_port_is_dpout(tunnel->dst_port))
 533                 return tb_dp_port_enable(tunnel->dst_port, active);
 534
 535         return 0;
 536 }
 537
 538 static int tb_dp_consumed_bandwidth(struct tb_tunnel *tunnel)
 539 {
 540         struct tb_port *in = tunnel->src_port;
 541         const struct tb_switch *sw = in->sw;
 542         u32 val, rate = 0, lanes = 0;
 543         int ret;
 544
 545         if (tb_dp_is_usb4(sw)) {
 546                 int timeout = 10;
 547
 548                 /*
 549                  * Wait for DPRX done. Normally it should be already set
 550                  * for active tunnel.
 551                  */
 552                 do {
 553                         ret = tb_port_read(in, &val, TB_CFG_PORT,
 554                                            in->cap_adap + DP_COMMON_CAP, 1);
 555                         if (ret)
 556                                 return ret;
 557
 558                         if (val & DP_COMMON_CAP_DPRX_DONE) {
 559                                 rate = tb_dp_cap_get_rate(val);
 560                                 lanes = tb_dp_cap_get_lanes(val);
 561                                 break;
 562                         }
 563                         msleep(250);
 564                 } while (timeout--);
 565
 566                 if (!timeout)
 567                         return -ETIMEDOUT;
 568         } else if (sw->generation >= 2) {
 569                 /*
 570                  * Read from the copied remote cap so that we take into
 571                  * account if capabilities were reduced during exchange.
 572                  */
 573                 ret = tb_port_read(in, &val, TB_CFG_PORT,
 574                                    in->cap_adap + DP_REMOTE_CAP, 1);
 575                 if (ret)
 576                         return ret;
 577
 578                 rate = tb_dp_cap_get_rate(val);
 579                 lanes = tb_dp_cap_get_lanes(val);
 580         } else {
 581                 /* No bandwidth management for legacy devices  */
 582                 return 0;
 583         }
 584
 585         return tb_dp_bandwidth(rate, lanes);
 586 }
 587
 588 static void tb_dp_init_aux_path(struct tb_path *path)
 589 {
 590         int i;
 591
 592         path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
 593         path->egress_shared_buffer = TB_PATH_NONE;
 594         path->ingress_fc_enable = TB_PATH_ALL;
 595         path->ingress_shared_buffer = TB_PATH_NONE;
 596         path->priority = 2;
 597         path->weight = 1;
 598
 599         for (i = 0; i < path->path_length; i++)
 600                 path->hops[i].initial_credits = 1;
 601 }
 602
 603 static void tb_dp_init_video_path(struct tb_path *path, bool discover)
 604 {
 605         u32 nfc_credits = path->hops[0].in_port->config.nfc_credits;
 606
 607         path->egress_fc_enable = TB_PATH_NONE;
 608         path->egress_shared_buffer = TB_PATH_NONE;
 609         path->ingress_fc_enable = TB_PATH_NONE;
 610         path->ingress_shared_buffer = TB_PATH_NONE;
 611         path->priority = 1;
 612         path->weight = 1;
 613
 614         if (discover) {
 615                 path->nfc_credits = nfc_credits & ADP_CS_4_NFC_BUFFERS_MASK;
 616         } else {
 617                 u32 max_credits;
 618
 619                 max_credits = (nfc_credits & ADP_CS_4_TOTAL_BUFFERS_MASK) >>
 620                         ADP_CS_4_TOTAL_BUFFERS_SHIFT;
 621                 /* Leave some credits for AUX path */
 622                 path->nfc_credits = min(max_credits - 2, 12U);
 623         }
 624 }
 625
 626 /**
 627  * tb_tunnel_discover_dp() - Discover existing Display Port tunnels
 628  * @tb: Pointer to the domain structure
 629  * @in: DP in adapter
 630  *
 631  * If @in adapter is active, follows the tunnel to the DP out adapter
 632  * and back. Returns the discovered tunnel or %NULL if there was no
 633  * tunnel.
 634  *
 635  * Return: DP tunnel or %NULL if no tunnel found.
 636  */
 637 struct tb_tunnel *tb_tunnel_discover_dp(struct tb *tb, struct tb_port *in)
 638 {
 639         struct tb_tunnel *tunnel;
 640         struct tb_port *port;
 641         struct tb_path *path;
 642
 643         if (!tb_dp_port_is_enabled(in))
 644                 return NULL;
 645
 646         tunnel = tb_tunnel_alloc(tb, 3, TB_TUNNEL_DP);
 647         if (!tunnel)
 648                 return NULL;
 649
 650         tunnel->init = tb_dp_xchg_caps;
 651         tunnel->activate = tb_dp_activate;
 652         tunnel->consumed_bandwidth = tb_dp_consumed_bandwidth;
 653         tunnel->src_port = in;
 654
 655         path = tb_path_discover(in, TB_DP_VIDEO_HOPID, NULL, -1,
 656                                 &tunnel->dst_port, "Video");
 657         if (!path) {
 658                 /* Just disable the DP IN port */
 659                 tb_dp_port_enable(in, false);
 660                 goto err_free;
 661         }
 662         tunnel->paths[TB_DP_VIDEO_PATH_OUT] = path;
 663         tb_dp_init_video_path(tunnel->paths[TB_DP_VIDEO_PATH_OUT], true);
 664
 665         path = tb_path_discover(in, TB_DP_AUX_TX_HOPID, NULL, -1, NULL, "AUX TX");
 666         if (!path)
 667                 goto err_deactivate;
 668         tunnel->paths[TB_DP_AUX_PATH_OUT] = path;
 669         tb_dp_init_aux_path(tunnel->paths[TB_DP_AUX_PATH_OUT]);
 670
 671         path = tb_path_discover(tunnel->dst_port, -1, in, TB_DP_AUX_RX_HOPID,
 672                                 &port, "AUX RX");
 673         if (!path)
 674                 goto err_deactivate;
 675         tunnel->paths[TB_DP_AUX_PATH_IN] = path;
 676         tb_dp_init_aux_path(tunnel->paths[TB_DP_AUX_PATH_IN]);
 677
 678         /* Validate that the tunnel is complete */
 679         if (!tb_port_is_dpout(tunnel->dst_port)) {
 680                 tb_port_warn(in, "path does not end on a DP adapter, cleaning up\n");
 681                 goto err_deactivate;
 682         }
 683
 684         if (!tb_dp_port_is_enabled(tunnel->dst_port))
 685                 goto err_deactivate;
 686
 687         if (!tb_dp_port_hpd_is_active(tunnel->dst_port))
 688                 goto err_deactivate;
 689
 690         if (port != tunnel->src_port) {
 691                 tb_tunnel_warn(tunnel, "path is not complete, cleaning up\n");
 692                 goto err_deactivate;
 693         }
 694
 695         tb_tunnel_dbg(tunnel, "discovered\n");
 696         return tunnel;
 697
 698 err_deactivate:
 699         tb_tunnel_deactivate(tunnel);
 700 err_free:
 701         tb_tunnel_free(tunnel);
 702
 703         return NULL;
 704 }
 705
 706 /**
 707  * tb_tunnel_alloc_dp() - allocate a Display Port tunnel
 708  * @tb: Pointer to the domain structure
 709  * @in: DP in adapter port
 710  * @out: DP out adapter port
 711  * @max_bw: Maximum available bandwidth for the DP tunnel (%0 if not limited)
 712  *
 713  * Allocates a tunnel between @in and @out that is capable of tunneling
 714  * Display Port traffic.
 715  *
 716  * Return: Returns a tb_tunnel on success or NULL on failure.
 717  */
 718 struct tb_tunnel *tb_tunnel_alloc_dp(struct tb *tb, struct tb_port *in,
 719                                      struct tb_port *out, int max_bw)
 720 {
 721         struct tb_tunnel *tunnel;
 722         struct tb_path **paths;
 723         struct tb_path *path;
 724
 725         if (WARN_ON(!in->cap_adap || !out->cap_adap))
 726                 return NULL;
 727
 728         tunnel = tb_tunnel_alloc(tb, 3, TB_TUNNEL_DP);
 729         if (!tunnel)
 730                 return NULL;
 731
 732         tunnel->init = tb_dp_xchg_caps;
 733         tunnel->activate = tb_dp_activate;
 734         tunnel->consumed_bandwidth = tb_dp_consumed_bandwidth;
 735         tunnel->src_port = in;
 736         tunnel->dst_port = out;
 737         tunnel->max_bw = max_bw;
 738
 739         paths = tunnel->paths;
 740
 741         path = tb_path_alloc(tb, in, TB_DP_VIDEO_HOPID, out, TB_DP_VIDEO_HOPID,
 742                              1, "Video");
 743         if (!path)
 744                 goto err_free;
 745         tb_dp_init_video_path(path, false);
 746         paths[TB_DP_VIDEO_PATH_OUT] = path;
 747
 748         path = tb_path_alloc(tb, in, TB_DP_AUX_TX_HOPID, out,
 749                              TB_DP_AUX_TX_HOPID, 1, "AUX TX");
 750         if (!path)
 751                 goto err_free;
 752         tb_dp_init_aux_path(path);
 753         paths[TB_DP_AUX_PATH_OUT] = path;
 754
 755         path = tb_path_alloc(tb, out, TB_DP_AUX_RX_HOPID, in,
 756                              TB_DP_AUX_RX_HOPID, 1, "AUX RX");
 757         if (!path)
 758                 goto err_free;
 759         tb_dp_init_aux_path(path);
 760         paths[TB_DP_AUX_PATH_IN] = path;
 761
 762         return tunnel;
 763
 764 err_free:
 765         tb_tunnel_free(tunnel);
 766         return NULL;
 767 }
 768
 769 static u32 tb_dma_credits(struct tb_port *nhi)
 770 {
 771         u32 max_credits;
 772
 773         max_credits = (nhi->config.nfc_credits & ADP_CS_4_TOTAL_BUFFERS_MASK) >>
 774                 ADP_CS_4_TOTAL_BUFFERS_SHIFT;
 775         return min(max_credits, 13U);
 776 }
 777
 778 static int tb_dma_activate(struct tb_tunnel *tunnel, bool active)
 779 {
 780         struct tb_port *nhi = tunnel->src_port;
 781         u32 credits;
 782
 783         credits = active ? tb_dma_credits(nhi) : 0;
 784         return tb_port_set_initial_credits(nhi, credits);
 785 }
 786
 787 static void tb_dma_init_path(struct tb_path *path, unsigned int isb,
 788                              unsigned int efc, u32 credits)
 789 {
 790         int i;
 791
 792         path->egress_fc_enable = efc;
 793         path->ingress_fc_enable = TB_PATH_ALL;
 794         path->egress_shared_buffer = TB_PATH_NONE;
 795         path->ingress_shared_buffer = isb;
 796         path->priority = 5;
 797         path->weight = 1;
 798         path->clear_fc = true;
 799
 800         for (i = 0; i < path->path_length; i++)
 801                 path->hops[i].initial_credits = credits;
 802 }
 803
 804 /**
 805  * tb_tunnel_alloc_dma() - allocate a DMA tunnel
 806  * @tb: Pointer to the domain structure
 807  * @nhi: Host controller port
 808  * @dst: Destination null port which the other domain is connected to
 809  * @transmit_ring: NHI ring number used to send packets towards the
 810  *                 other domain
 811  * @transmit_path: HopID used for transmitting packets
 812  * @receive_ring: NHI ring number used to receive packets from the
 813  *                other domain
 814  * @reveive_path: HopID used for receiving packets
 815  *
 816  * Return: Returns a tb_tunnel on success or NULL on failure.
 817  */
 818 struct tb_tunnel *tb_tunnel_alloc_dma(struct tb *tb, struct tb_port *nhi,
 819                                       struct tb_port *dst, int transmit_ring,
 820                                       int transmit_path, int receive_ring,
 821                                       int receive_path)
 822 {
 823         struct tb_tunnel *tunnel;
 824         struct tb_path *path;
 825         u32 credits;
 826
 827         tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_DMA);
 828         if (!tunnel)
 829                 return NULL;
 830
 831         tunnel->activate = tb_dma_activate;
 832         tunnel->src_port = nhi;
 833         tunnel->dst_port = dst;
 834
 835         credits = tb_dma_credits(nhi);
 836
 837         path = tb_path_alloc(tb, dst, receive_path, nhi, receive_ring, 0, "DMA RX");
 838         if (!path) {
 839                 tb_tunnel_free(tunnel);
 840                 return NULL;
 841         }
 842         tb_dma_init_path(path, TB_PATH_NONE, TB_PATH_SOURCE | TB_PATH_INTERNAL,
 843                          credits);
 844         tunnel->paths[TB_DMA_PATH_IN] = path;
 845
 846         path = tb_path_alloc(tb, nhi, transmit_ring, dst, transmit_path, 0, "DMA TX");
 847         if (!path) {
 848                 tb_tunnel_free(tunnel);
 849                 return NULL;
 850         }
 851         tb_dma_init_path(path, TB_PATH_SOURCE, TB_PATH_ALL, credits);
 852         tunnel->paths[TB_DMA_PATH_OUT] = path;
 853
 854         return tunnel;
 855 }
 856
 857 static int tb_usb3_activate(struct tb_tunnel *tunnel, bool activate)
 858 {
 859         int res;
 860
 861         res = tb_usb3_port_enable(tunnel->src_port, activate);
 862         if (res)
 863                 return res;
 864
 865         if (tb_port_is_usb3_up(tunnel->dst_port))
 866                 return tb_usb3_port_enable(tunnel->dst_port, activate);
 867
 868         return 0;
 869 }
 870
 871 static void tb_usb3_init_path(struct tb_path *path)
 872 {
 873         path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
 874         path->egress_shared_buffer = TB_PATH_NONE;
 875         path->ingress_fc_enable = TB_PATH_ALL;
 876         path->ingress_shared_buffer = TB_PATH_NONE;
 877         path->priority = 3;
 878         path->weight = 3;
 879         path->drop_packages = 0;
 880         path->nfc_credits = 0;
 881         path->hops[0].initial_credits = 7;
 882         path->hops[1].initial_credits =
 883                 tb_initial_credits(path->hops[1].in_port->sw);
 884 }
 885
 886 /**
 887  * tb_tunnel_discover_usb3() - Discover existing USB3 tunnels
 888  * @tb: Pointer to the domain structure
 889  * @down: USB3 downstream adapter
 890  *
 891  * If @down adapter is active, follows the tunnel to the USB3 upstream
 892  * adapter and back. Returns the discovered tunnel or %NULL if there was
 893  * no tunnel.
 894  */
 895 struct tb_tunnel *tb_tunnel_discover_usb3(struct tb *tb, struct tb_port *down)
 896 {
 897         struct tb_tunnel *tunnel;
 898         struct tb_path *path;
 899
 900         if (!tb_usb3_port_is_enabled(down))
 901                 return NULL;
 902
 903         tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_USB3);
 904         if (!tunnel)
 905                 return NULL;
 906
 907         tunnel->activate = tb_usb3_activate;
 908         tunnel->src_port = down;
 909
 910         /*
 911          * Discover both paths even if they are not complete. We will
 912          * clean them up by calling tb_tunnel_deactivate() below in that
 913          * case.
 914          */
 915         path = tb_path_discover(down, TB_USB3_HOPID, NULL, -1,
 916                                 &tunnel->dst_port, "USB3 Up");
 917         if (!path) {
 918                 /* Just disable the downstream port */
 919                 tb_usb3_port_enable(down, false);
 920                 goto err_free;
 921         }
 922         tunnel->paths[TB_USB3_PATH_UP] = path;
 923         tb_usb3_init_path(tunnel->paths[TB_USB3_PATH_UP]);
 924
 925         path = tb_path_discover(tunnel->dst_port, -1, down, TB_USB3_HOPID, NULL,
 926                                 "USB3 Down");
 927         if (!path)
 928                 goto err_deactivate;
 929         tunnel->paths[TB_USB3_PATH_DOWN] = path;
 930         tb_usb3_init_path(tunnel->paths[TB_USB3_PATH_DOWN]);
 931
 932         /* Validate that the tunnel is complete */
 933         if (!tb_port_is_usb3_up(tunnel->dst_port)) {
 934                 tb_port_warn(tunnel->dst_port,
 935                              "path does not end on an USB3 adapter, cleaning up\n");
 936                 goto err_deactivate;
 937         }
 938
 939         if (down != tunnel->src_port) {
 940                 tb_tunnel_warn(tunnel, "path is not complete, cleaning up\n");
 941                 goto err_deactivate;
 942         }
 943
 944         if (!tb_usb3_port_is_enabled(tunnel->dst_port)) {
 945                 tb_tunnel_warn(tunnel,
 946                                "tunnel is not fully activated, cleaning up\n");
 947                 goto err_deactivate;
 948         }
 949
 950         tb_tunnel_dbg(tunnel, "discovered\n");
 951         return tunnel;
 952
 953 err_deactivate:
 954         tb_tunnel_deactivate(tunnel);
 955 err_free:
 956         tb_tunnel_free(tunnel);
 957
 958         return NULL;
 959 }
 960
 961 /**
 962  * tb_tunnel_alloc_usb3() - allocate a USB3 tunnel
 963  * @tb: Pointer to the domain structure
 964  * @up: USB3 upstream adapter port
 965  * @down: USB3 downstream adapter port
 966  *
 967  * Allocate an USB3 tunnel. The ports must be of type @TB_TYPE_USB3_UP and
 968  * @TB_TYPE_USB3_DOWN.
 969  *
 970  * Return: Returns a tb_tunnel on success or %NULL on failure.
 971  */
 972 struct tb_tunnel *tb_tunnel_alloc_usb3(struct tb *tb, struct tb_port *up,
 973                                        struct tb_port *down)
 974 {
 975         struct tb_tunnel *tunnel;
 976         struct tb_path *path;
 977
 978         tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_USB3);
 979         if (!tunnel)
 980                 return NULL;
 981
 982         tunnel->activate = tb_usb3_activate;
 983         tunnel->src_port = down;
 984         tunnel->dst_port = up;
 985
 986         path = tb_path_alloc(tb, down, TB_USB3_HOPID, up, TB_USB3_HOPID, 0,
 987                              "USB3 Down");
 988         if (!path) {
 989                 tb_tunnel_free(tunnel);
 990                 return NULL;
 991         }
 992         tb_usb3_init_path(path);
 993         tunnel->paths[TB_USB3_PATH_DOWN] = path;
 994
 995         path = tb_path_alloc(tb, up, TB_USB3_HOPID, down, TB_USB3_HOPID, 0,
 996                              "USB3 Up");
 997         if (!path) {
 998                 tb_tunnel_free(tunnel);
 999                 return NULL;
1000         }
1001         tb_usb3_init_path(path);
1002         tunnel->paths[TB_USB3_PATH_UP] = path;
1003
1004         return tunnel;
1005 }
1006
1007 /**
1008  * tb_tunnel_free() - free a tunnel
1009  * @tunnel: Tunnel to be freed
1010  *
1011  * Frees a tunnel. The tunnel does not need to be deactivated.
1012  */
1013 void tb_tunnel_free(struct tb_tunnel *tunnel)
1014 {
1015         int i;
1016
1017         if (!tunnel)
1018                 return;
1019
1020         for (i = 0; i < tunnel->npaths; i++) {
1021                 if (tunnel->paths[i])
1022                         tb_path_free(tunnel->paths[i]);
1023         }
1024
1025         kfree(tunnel->paths);
1026         kfree(tunnel);
1027 }
1028
1029 /**
1030  * tb_tunnel_is_invalid - check whether an activated path is still valid
1031  * @tunnel: Tunnel to check
1032  */
1033 bool tb_tunnel_is_invalid(struct tb_tunnel *tunnel)
1034 {
1035         int i;
1036
1037         for (i = 0; i < tunnel->npaths; i++) {
1038                 WARN_ON(!tunnel->paths[i]->activated);
1039                 if (tb_path_is_invalid(tunnel->paths[i]))
1040                         return true;
1041         }
1042
1043         return false;
1044 }
1045
1046 /**
1047  * tb_tunnel_restart() - activate a tunnel after a hardware reset
1048  * @tunnel: Tunnel to restart
1049  *
1050  * Return: 0 on success and negative errno in case if failure
1051  */
1052 int tb_tunnel_restart(struct tb_tunnel *tunnel)
1053 {
1054         int res, i;
1055
1056         tb_tunnel_dbg(tunnel, "activating\n");
1057
1058         /*
1059          * Make sure all paths are properly disabled before enabling
1060          * them again.
1061          */
1062         for (i = 0; i < tunnel->npaths; i++) {
1063                 if (tunnel->paths[i]->activated) {
1064                         tb_path_deactivate(tunnel->paths[i]);
1065                         tunnel->paths[i]->activated = false;
1066                 }
1067         }
1068
1069         if (tunnel->init) {
1070                 res = tunnel->init(tunnel);
1071                 if (res)
1072                         return res;
1073         }
1074
1075         for (i = 0; i < tunnel->npaths; i++) {
1076                 res = tb_path_activate(tunnel->paths[i]);
1077                 if (res)
1078                         goto err;
1079         }
1080
1081         if (tunnel->activate) {
1082                 res = tunnel->activate(tunnel, true);
1083                 if (res)
1084                         goto err;
1085         }
1086
1087         return 0;
1088
1089 err:
1090         tb_tunnel_warn(tunnel, "activation failed\n");
1091         tb_tunnel_deactivate(tunnel);
1092         return res;
1093 }
1094
1095 /**
1096  * tb_tunnel_activate() - activate a tunnel
1097  * @tunnel: Tunnel to activate
1098  *
1099  * Return: Returns 0 on success or an error code on failure.
1100  */
1101 int tb_tunnel_activate(struct tb_tunnel *tunnel)
1102 {
1103         int i;
1104
1105         for (i = 0; i < tunnel->npaths; i++) {
1106                 if (tunnel->paths[i]->activated) {
1107                         tb_tunnel_WARN(tunnel,
1108                                        "trying to activate an already activated tunnel\n");
1109                         return -EINVAL;
1110                 }
1111         }
1112
1113         return tb_tunnel_restart(tunnel);
1114 }
1115
1116 /**
1117  * tb_tunnel_deactivate() - deactivate a tunnel
1118  * @tunnel: Tunnel to deactivate
1119  */
1120 void tb_tunnel_deactivate(struct tb_tunnel *tunnel)
1121 {
1122         int i;
1123
1124         tb_tunnel_dbg(tunnel, "deactivating\n");
1125
1126         if (tunnel->activate)
1127                 tunnel->activate(tunnel, false);
1128
1129         for (i = 0; i < tunnel->npaths; i++) {
1130                 if (tunnel->paths[i] && tunnel->paths[i]->activated)
1131                         tb_path_deactivate(tunnel->paths[i]);
1132         }
1133 }
1134
1135 /**
1136  * tb_tunnel_switch_on_path() - Does the tunnel go through switch
1137  * @tunnel: Tunnel to check
1138  * @sw: Switch to check
1139  *
1140  * Returns true if @tunnel goes through @sw (direction does not matter),
1141  * false otherwise.
1142  */
1143 bool tb_tunnel_switch_on_path(const struct tb_tunnel *tunnel,
1144                               const struct tb_switch *sw)
1145 {
1146         int i;
1147
1148         for (i = 0; i < tunnel->npaths; i++) {
1149                 if (!tunnel->paths[i])
1150                         continue;
1151                 if (tb_path_switch_on_path(tunnel->paths[i], sw))
1152                         return true;
1153         }
1154
1155         return false;
1156 }
1157
1158 static bool tb_tunnel_is_active(const struct tb_tunnel *tunnel)
1159 {
1160         int i;
1161
1162         for (i = 0; i < tunnel->npaths; i++) {
1163                 if (!tunnel->paths[i])
1164                         return false;
1165                 if (!tunnel->paths[i]->activated)
1166                         return false;
1167         }
1168
1169         return true;
1170 }
1171
1172 /**
1173  * tb_tunnel_consumed_bandwidth() - Return bandwidth consumed by the tunnel
1174  * @tunnel: Tunnel to check
1175  *
1176  * Returns bandwidth currently consumed by @tunnel and %0 if the @tunnel
1177  * is not active or does consume bandwidth.
1178  */
1179 int tb_tunnel_consumed_bandwidth(struct tb_tunnel *tunnel)
1180 {
1181         if (!tb_tunnel_is_active(tunnel))
1182                 return 0;
1183
1184         if (tunnel->consumed_bandwidth) {
1185                 int ret = tunnel->consumed_bandwidth(tunnel);
1186
1187                 tb_tunnel_dbg(tunnel, "consumed bandwidth %d Mb/s\n", ret);
1188                 return ret;
1189         }
1190
1191         return 0;
1192 }