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 #include <linux/ktime.h>
  13 #include <linux/string_helpers.h>
  14
  15 #include "tunnel.h"
  16 #include "tb.h"
  17
  18 /* PCIe adapters use always HopID of 8 for both directions */
  19 #define TB_PCI_HOPID                    8
  20
  21 #define TB_PCI_PATH_DOWN                0
  22 #define TB_PCI_PATH_UP                  1
  23
  24 #define TB_PCI_PRIORITY                 3
  25 #define TB_PCI_WEIGHT                   1
  26
  27 /* USB3 adapters use always HopID of 8 for both directions */
  28 #define TB_USB3_HOPID                   8
  29
  30 #define TB_USB3_PATH_DOWN               0
  31 #define TB_USB3_PATH_UP                 1
  32
  33 #define TB_USB3_PRIORITY                3
  34 #define TB_USB3_WEIGHT                  2
  35
  36 /* DP adapters use HopID 8 for AUX and 9 for Video */
  37 #define TB_DP_AUX_TX_HOPID              8
  38 #define TB_DP_AUX_RX_HOPID              8
  39 #define TB_DP_VIDEO_HOPID               9
  40
  41 #define TB_DP_VIDEO_PATH_OUT            0
  42 #define TB_DP_AUX_PATH_OUT              1
  43 #define TB_DP_AUX_PATH_IN               2
  44
  45 #define TB_DP_VIDEO_PRIORITY            1
  46 #define TB_DP_VIDEO_WEIGHT              1
  47
  48 #define TB_DP_AUX_PRIORITY              2
  49 #define TB_DP_AUX_WEIGHT                1
  50
  51 /* Minimum number of credits needed for PCIe path */
  52 #define TB_MIN_PCIE_CREDITS             6U
  53 /*
  54  * Number of credits we try to allocate for each DMA path if not limited
  55  * by the host router baMaxHI.
  56  */
  57 #define TB_DMA_CREDITS                  14
  58 /* Minimum number of credits for DMA path */
  59 #define TB_MIN_DMA_CREDITS              1
  60
  61 #define TB_DMA_PRIORITY                 5
  62 #define TB_DMA_WEIGHT                   1
  63
  64 /*
  65  * Reserve additional bandwidth for USB 3.x and PCIe bulk traffic
  66  * according to USB4 v2 Connection Manager guide. This ends up reserving
  67  * 1500 Mb/s for PCIe and 3000 Mb/s for USB 3.x taking weights into
  68  * account.
  69  */
  70 #define USB4_V2_PCI_MIN_BANDWIDTH       (1500 * TB_PCI_WEIGHT)
  71 #define USB4_V2_USB3_MIN_BANDWIDTH      (1500 * TB_USB3_WEIGHT)
  72
  73 static unsigned int dma_credits = TB_DMA_CREDITS;
  74 module_param(dma_credits, uint, 0444);
  75 MODULE_PARM_DESC(dma_credits, "specify custom credits for DMA tunnels (default: "
  76                 __MODULE_STRING(TB_DMA_CREDITS) ")");
  77
  78 static bool bw_alloc_mode = true;
  79 module_param(bw_alloc_mode, bool, 0444);
  80 MODULE_PARM_DESC(bw_alloc_mode,
  81                  "enable bandwidth allocation mode if supported (default: true)");
  82
  83 static const char * const tb_tunnel_names[] = { "PCI", "DP", "DMA", "USB3" };
  84
  85 static inline unsigned int tb_usable_credits(const struct tb_port *port)
  86 {
  87         return port->total_credits - port->ctl_credits;
  88 }
  89
  90 /**
  91  * tb_available_credits() - Available credits for PCIe and DMA
  92  * @port: Lane adapter to check
  93  * @max_dp_streams: If non-%NULL stores maximum number of simultaneous DP
  94  *                  streams possible through this lane adapter
  95  */
  96 static unsigned int tb_available_credits(const struct tb_port *port,
  97                                          size_t *max_dp_streams)
  98 {
  99         const struct tb_switch *sw = port->sw;
 100         int credits, usb3, pcie, spare;
 101         size_t ndp;
 102
 103         usb3 = tb_acpi_may_tunnel_usb3() ? sw->max_usb3_credits : 0;
 104         pcie = tb_acpi_may_tunnel_pcie() ? sw->max_pcie_credits : 0;
 105
 106         if (tb_acpi_is_xdomain_allowed()) {
 107                 spare = min_not_zero(sw->max_dma_credits, dma_credits);
 108                 /* Add some credits for potential second DMA tunnel */
 109                 spare += TB_MIN_DMA_CREDITS;
 110         } else {
 111                 spare = 0;
 112         }
 113
 114         credits = tb_usable_credits(port);
 115         if (tb_acpi_may_tunnel_dp()) {
 116                 /*
 117                  * Maximum number of DP streams possible through the
 118                  * lane adapter.
 119                  */
 120                 if (sw->min_dp_aux_credits + sw->min_dp_main_credits)
 121                         ndp = (credits - (usb3 + pcie + spare)) /
 122                               (sw->min_dp_aux_credits + sw->min_dp_main_credits);
 123                 else
 124                         ndp = 0;
 125         } else {
 126                 ndp = 0;
 127         }
 128         credits -= ndp * (sw->min_dp_aux_credits + sw->min_dp_main_credits);
 129         credits -= usb3;
 130
 131         if (max_dp_streams)
 132                 *max_dp_streams = ndp;
 133
 134         return credits > 0 ? credits : 0;
 135 }
 136
 137 static void tb_init_pm_support(struct tb_path_hop *hop)
 138 {
 139         struct tb_port *out_port = hop->out_port;
 140         struct tb_port *in_port = hop->in_port;
 141
 142         if (tb_port_is_null(in_port) && tb_port_is_null(out_port) &&
 143             usb4_switch_version(in_port->sw) >= 2)
 144                 hop->pm_support = true;
 145 }
 146
 147 static struct tb_tunnel *tb_tunnel_alloc(struct tb *tb, size_t npaths,
 148                                          enum tb_tunnel_type type)
 149 {
 150         struct tb_tunnel *tunnel;
 151
 152         tunnel = kzalloc(sizeof(*tunnel), GFP_KERNEL);
 153         if (!tunnel)
 154                 return NULL;
 155
 156         tunnel->paths = kcalloc(npaths, sizeof(tunnel->paths[0]), GFP_KERNEL);
 157         if (!tunnel->paths) {
 158                 tb_tunnel_free(tunnel);
 159                 return NULL;
 160         }
 161
 162         INIT_LIST_HEAD(&tunnel->list);
 163         tunnel->tb = tb;
 164         tunnel->npaths = npaths;
 165         tunnel->type = type;
 166
 167         return tunnel;
 168 }
 169
 170 static int tb_pci_set_ext_encapsulation(struct tb_tunnel *tunnel, bool enable)
 171 {
 172         struct tb_port *port = tb_upstream_port(tunnel->dst_port->sw);
 173         int ret;
 174
 175         /* Only supported of both routers are at least USB4 v2 */
 176         if (tb_port_get_link_generation(port) < 4)
 177                 return 0;
 178
 179         ret = usb4_pci_port_set_ext_encapsulation(tunnel->src_port, enable);
 180         if (ret)
 181                 return ret;
 182
 183         ret = usb4_pci_port_set_ext_encapsulation(tunnel->dst_port, enable);
 184         if (ret)
 185                 return ret;
 186
 187         tb_tunnel_dbg(tunnel, "extended encapsulation %s\n",
 188                       str_enabled_disabled(enable));
 189         return 0;
 190 }
 191
 192 static int tb_pci_activate(struct tb_tunnel *tunnel, bool activate)
 193 {
 194         int res;
 195
 196         if (activate) {
 197                 res = tb_pci_set_ext_encapsulation(tunnel, activate);
 198                 if (res)
 199                         return res;
 200         }
 201
 202         res = tb_pci_port_enable(tunnel->src_port, activate);
 203         if (res)
 204                 return res;
 205
 206         if (tb_port_is_pcie_up(tunnel->dst_port)) {
 207                 res = tb_pci_port_enable(tunnel->dst_port, activate);
 208                 if (res)
 209                         return res;
 210         }
 211
 212         return activate ? 0 : tb_pci_set_ext_encapsulation(tunnel, activate);
 213 }
 214
 215 static int tb_pci_init_credits(struct tb_path_hop *hop)
 216 {
 217         struct tb_port *port = hop->in_port;
 218         struct tb_switch *sw = port->sw;
 219         unsigned int credits;
 220
 221         if (tb_port_use_credit_allocation(port)) {
 222                 unsigned int available;
 223
 224                 available = tb_available_credits(port, NULL);
 225                 credits = min(sw->max_pcie_credits, available);
 226
 227                 if (credits < TB_MIN_PCIE_CREDITS)
 228                         return -ENOSPC;
 229
 230                 credits = max(TB_MIN_PCIE_CREDITS, credits);
 231         } else {
 232                 if (tb_port_is_null(port))
 233                         credits = port->bonded ? 32 : 16;
 234                 else
 235                         credits = 7;
 236         }
 237
 238         hop->initial_credits = credits;
 239         return 0;
 240 }
 241
 242 static int tb_pci_init_path(struct tb_path *path)
 243 {
 244         struct tb_path_hop *hop;
 245
 246         path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
 247         path->egress_shared_buffer = TB_PATH_NONE;
 248         path->ingress_fc_enable = TB_PATH_ALL;
 249         path->ingress_shared_buffer = TB_PATH_NONE;
 250         path->priority = TB_PCI_PRIORITY;
 251         path->weight = TB_PCI_WEIGHT;
 252         path->drop_packages = 0;
 253
 254         tb_path_for_each_hop(path, hop) {
 255                 int ret;
 256
 257                 ret = tb_pci_init_credits(hop);
 258                 if (ret)
 259                         return ret;
 260         }
 261
 262         return 0;
 263 }
 264
 265 /**
 266  * tb_tunnel_discover_pci() - Discover existing PCIe tunnels
 267  * @tb: Pointer to the domain structure
 268  * @down: PCIe downstream adapter
 269  * @alloc_hopid: Allocate HopIDs from visited ports
 270  *
 271  * If @down adapter is active, follows the tunnel to the PCIe upstream
 272  * adapter and back. Returns the discovered tunnel or %NULL if there was
 273  * no tunnel.
 274  */
 275 struct tb_tunnel *tb_tunnel_discover_pci(struct tb *tb, struct tb_port *down,
 276                                          bool alloc_hopid)
 277 {
 278         struct tb_tunnel *tunnel;
 279         struct tb_path *path;
 280
 281         if (!tb_pci_port_is_enabled(down))
 282                 return NULL;
 283
 284         tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_PCI);
 285         if (!tunnel)
 286                 return NULL;
 287
 288         tunnel->activate = tb_pci_activate;
 289         tunnel->src_port = down;
 290
 291         /*
 292          * Discover both paths even if they are not complete. We will
 293          * clean them up by calling tb_tunnel_deactivate() below in that
 294          * case.
 295          */
 296         path = tb_path_discover(down, TB_PCI_HOPID, NULL, -1,
 297                                 &tunnel->dst_port, "PCIe Up", alloc_hopid);
 298         if (!path) {
 299                 /* Just disable the downstream port */
 300                 tb_pci_port_enable(down, false);
 301                 goto err_free;
 302         }
 303         tunnel->paths[TB_PCI_PATH_UP] = path;
 304         if (tb_pci_init_path(tunnel->paths[TB_PCI_PATH_UP]))
 305                 goto err_free;
 306
 307         path = tb_path_discover(tunnel->dst_port, -1, down, TB_PCI_HOPID, NULL,
 308                                 "PCIe Down", alloc_hopid);
 309         if (!path)
 310                 goto err_deactivate;
 311         tunnel->paths[TB_PCI_PATH_DOWN] = path;
 312         if (tb_pci_init_path(tunnel->paths[TB_PCI_PATH_DOWN]))
 313                 goto err_deactivate;
 314
 315         /* Validate that the tunnel is complete */
 316         if (!tb_port_is_pcie_up(tunnel->dst_port)) {
 317                 tb_port_warn(tunnel->dst_port,
 318                              "path does not end on a PCIe adapter, cleaning up\n");
 319                 goto err_deactivate;
 320         }
 321
 322         if (down != tunnel->src_port) {
 323                 tb_tunnel_warn(tunnel, "path is not complete, cleaning up\n");
 324                 goto err_deactivate;
 325         }
 326
 327         if (!tb_pci_port_is_enabled(tunnel->dst_port)) {
 328                 tb_tunnel_warn(tunnel,
 329                                "tunnel is not fully activated, cleaning up\n");
 330                 goto err_deactivate;
 331         }
 332
 333         tb_tunnel_dbg(tunnel, "discovered\n");
 334         return tunnel;
 335
 336 err_deactivate:
 337         tb_tunnel_deactivate(tunnel);
 338 err_free:
 339         tb_tunnel_free(tunnel);
 340
 341         return NULL;
 342 }
 343
 344 /**
 345  * tb_tunnel_alloc_pci() - allocate a pci tunnel
 346  * @tb: Pointer to the domain structure
 347  * @up: PCIe upstream adapter port
 348  * @down: PCIe downstream adapter port
 349  *
 350  * Allocate a PCI tunnel. The ports must be of type TB_TYPE_PCIE_UP and
 351  * TB_TYPE_PCIE_DOWN.
 352  *
 353  * Return: Returns a tb_tunnel on success or NULL on failure.
 354  */
 355 struct tb_tunnel *tb_tunnel_alloc_pci(struct tb *tb, struct tb_port *up,
 356                                       struct tb_port *down)
 357 {
 358         struct tb_tunnel *tunnel;
 359         struct tb_path *path;
 360
 361         tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_PCI);
 362         if (!tunnel)
 363                 return NULL;
 364
 365         tunnel->activate = tb_pci_activate;
 366         tunnel->src_port = down;
 367         tunnel->dst_port = up;
 368
 369         path = tb_path_alloc(tb, down, TB_PCI_HOPID, up, TB_PCI_HOPID, 0,
 370                              "PCIe Down");
 371         if (!path)
 372                 goto err_free;
 373         tunnel->paths[TB_PCI_PATH_DOWN] = path;
 374         if (tb_pci_init_path(path))
 375                 goto err_free;
 376
 377         path = tb_path_alloc(tb, up, TB_PCI_HOPID, down, TB_PCI_HOPID, 0,
 378                              "PCIe Up");
 379         if (!path)
 380                 goto err_free;
 381         tunnel->paths[TB_PCI_PATH_UP] = path;
 382         if (tb_pci_init_path(path))
 383                 goto err_free;
 384
 385         return tunnel;
 386
 387 err_free:
 388         tb_tunnel_free(tunnel);
 389         return NULL;
 390 }
 391
 392 /**
 393  * tb_tunnel_reserved_pci() - Amount of bandwidth to reserve for PCIe
 394  * @port: Lane 0 adapter
 395  * @reserved_up: Upstream bandwidth in Mb/s to reserve
 396  * @reserved_down: Downstream bandwidth in Mb/s to reserve
 397  *
 398  * Can be called to any connected lane 0 adapter to find out how much
 399  * bandwidth needs to be left in reserve for possible PCIe bulk traffic.
 400  * Returns true if there is something to be reserved and writes the
 401  * amount to @reserved_down/@reserved_up. Otherwise returns false and
 402  * does not touch the parameters.
 403  */
 404 bool tb_tunnel_reserved_pci(struct tb_port *port, int *reserved_up,
 405                             int *reserved_down)
 406 {
 407         if (WARN_ON_ONCE(!port->remote))
 408                 return false;
 409
 410         if (!tb_acpi_may_tunnel_pcie())
 411                 return false;
 412
 413         if (tb_port_get_link_generation(port) < 4)
 414                 return false;
 415
 416         /* Must have PCIe adapters */
 417         if (tb_is_upstream_port(port)) {
 418                 if (!tb_switch_find_port(port->sw, TB_TYPE_PCIE_UP))
 419                         return false;
 420                 if (!tb_switch_find_port(port->remote->sw, TB_TYPE_PCIE_DOWN))
 421                         return false;
 422         } else {
 423                 if (!tb_switch_find_port(port->sw, TB_TYPE_PCIE_DOWN))
 424                         return false;
 425                 if (!tb_switch_find_port(port->remote->sw, TB_TYPE_PCIE_UP))
 426                         return false;
 427         }
 428
 429         *reserved_up = USB4_V2_PCI_MIN_BANDWIDTH;
 430         *reserved_down = USB4_V2_PCI_MIN_BANDWIDTH;
 431
 432         tb_port_dbg(port, "reserving %u/%u Mb/s for PCIe\n", *reserved_up,
 433                     *reserved_down);
 434         return true;
 435 }
 436
 437 static bool tb_dp_is_usb4(const struct tb_switch *sw)
 438 {
 439         /* Titan Ridge DP adapters need the same treatment as USB4 */
 440         return tb_switch_is_usb4(sw) || tb_switch_is_titan_ridge(sw);
 441 }
 442
 443 static int tb_dp_cm_handshake(struct tb_port *in, struct tb_port *out,
 444                               int timeout_msec)
 445 {
 446         ktime_t timeout = ktime_add_ms(ktime_get(), timeout_msec);
 447         u32 val;
 448         int ret;
 449
 450         /* Both ends need to support this */
 451         if (!tb_dp_is_usb4(in->sw) || !tb_dp_is_usb4(out->sw))
 452                 return 0;
 453
 454         ret = tb_port_read(out, &val, TB_CFG_PORT,
 455                            out->cap_adap + DP_STATUS_CTRL, 1);
 456         if (ret)
 457                 return ret;
 458
 459         val |= DP_STATUS_CTRL_UF | DP_STATUS_CTRL_CMHS;
 460
 461         ret = tb_port_write(out, &val, TB_CFG_PORT,
 462                             out->cap_adap + DP_STATUS_CTRL, 1);
 463         if (ret)
 464                 return ret;
 465
 466         do {
 467                 ret = tb_port_read(out, &val, TB_CFG_PORT,
 468                                    out->cap_adap + DP_STATUS_CTRL, 1);
 469                 if (ret)
 470                         return ret;
 471                 if (!(val & DP_STATUS_CTRL_CMHS))
 472                         return 0;
 473                 usleep_range(100, 150);
 474         } while (ktime_before(ktime_get(), timeout));
 475
 476         return -ETIMEDOUT;
 477 }
 478
 479 /*
 480  * Returns maximum possible rate from capability supporting only DP 2.0
 481  * and below. Used when DP BW allocation mode is not enabled.
 482  */
 483 static inline u32 tb_dp_cap_get_rate(u32 val)
 484 {
 485         u32 rate = (val & DP_COMMON_CAP_RATE_MASK) >> DP_COMMON_CAP_RATE_SHIFT;
 486
 487         switch (rate) {
 488         case DP_COMMON_CAP_RATE_RBR:
 489                 return 1620;
 490         case DP_COMMON_CAP_RATE_HBR:
 491                 return 2700;
 492         case DP_COMMON_CAP_RATE_HBR2:
 493                 return 5400;
 494         case DP_COMMON_CAP_RATE_HBR3:
 495                 return 8100;
 496         default:
 497                 return 0;
 498         }
 499 }
 500
 501 /*
 502  * Returns maximum possible rate from capability supporting DP 2.1
 503  * UHBR20, 13.5 and 10 rates as well. Use only when DP BW allocation
 504  * mode is enabled.
 505  */
 506 static inline u32 tb_dp_cap_get_rate_ext(u32 val)
 507 {
 508         if (val & DP_COMMON_CAP_UHBR20)
 509                 return 20000;
 510         else if (val & DP_COMMON_CAP_UHBR13_5)
 511                 return 13500;
 512         else if (val & DP_COMMON_CAP_UHBR10)
 513                 return 10000;
 514
 515         return tb_dp_cap_get_rate(val);
 516 }
 517
 518 static inline bool tb_dp_is_uhbr_rate(unsigned int rate)
 519 {
 520         return rate >= 10000;
 521 }
 522
 523 static inline u32 tb_dp_cap_set_rate(u32 val, u32 rate)
 524 {
 525         val &= ~DP_COMMON_CAP_RATE_MASK;
 526         switch (rate) {
 527         default:
 528                 WARN(1, "invalid rate %u passed, defaulting to 1620 MB/s\n", rate);
 529                 fallthrough;
 530         case 1620:
 531                 val |= DP_COMMON_CAP_RATE_RBR << DP_COMMON_CAP_RATE_SHIFT;
 532                 break;
 533         case 2700:
 534                 val |= DP_COMMON_CAP_RATE_HBR << DP_COMMON_CAP_RATE_SHIFT;
 535                 break;
 536         case 5400:
 537                 val |= DP_COMMON_CAP_RATE_HBR2 << DP_COMMON_CAP_RATE_SHIFT;
 538                 break;
 539         case 8100:
 540                 val |= DP_COMMON_CAP_RATE_HBR3 << DP_COMMON_CAP_RATE_SHIFT;
 541                 break;
 542         }
 543         return val;
 544 }
 545
 546 static inline u32 tb_dp_cap_get_lanes(u32 val)
 547 {
 548         u32 lanes = (val & DP_COMMON_CAP_LANES_MASK) >> DP_COMMON_CAP_LANES_SHIFT;
 549
 550         switch (lanes) {
 551         case DP_COMMON_CAP_1_LANE:
 552                 return 1;
 553         case DP_COMMON_CAP_2_LANES:
 554                 return 2;
 555         case DP_COMMON_CAP_4_LANES:
 556                 return 4;
 557         default:
 558                 return 0;
 559         }
 560 }
 561
 562 static inline u32 tb_dp_cap_set_lanes(u32 val, u32 lanes)
 563 {
 564         val &= ~DP_COMMON_CAP_LANES_MASK;
 565         switch (lanes) {
 566         default:
 567                 WARN(1, "invalid number of lanes %u passed, defaulting to 1\n",
 568                      lanes);
 569                 fallthrough;
 570         case 1:
 571                 val |= DP_COMMON_CAP_1_LANE << DP_COMMON_CAP_LANES_SHIFT;
 572                 break;
 573         case 2:
 574                 val |= DP_COMMON_CAP_2_LANES << DP_COMMON_CAP_LANES_SHIFT;
 575                 break;
 576         case 4:
 577                 val |= DP_COMMON_CAP_4_LANES << DP_COMMON_CAP_LANES_SHIFT;
 578                 break;
 579         }
 580         return val;
 581 }
 582
 583 static unsigned int tb_dp_bandwidth(unsigned int rate, unsigned int lanes)
 584 {
 585         /* Tunneling removes the DP 8b/10b 128/132b encoding */
 586         if (tb_dp_is_uhbr_rate(rate))
 587                 return rate * lanes * 128 / 132;
 588         return rate * lanes * 8 / 10;
 589 }
 590
 591 static int tb_dp_reduce_bandwidth(int max_bw, u32 in_rate, u32 in_lanes,
 592                                   u32 out_rate, u32 out_lanes, u32 *new_rate,
 593                                   u32 *new_lanes)
 594 {
 595         static const u32 dp_bw[][2] = {
 596                 /* Mb/s, lanes */
 597                 { 8100, 4 }, /* 25920 Mb/s */
 598                 { 5400, 4 }, /* 17280 Mb/s */
 599                 { 8100, 2 }, /* 12960 Mb/s */
 600                 { 2700, 4 }, /* 8640 Mb/s */
 601                 { 5400, 2 }, /* 8640 Mb/s */
 602                 { 8100, 1 }, /* 6480 Mb/s */
 603                 { 1620, 4 }, /* 5184 Mb/s */
 604                 { 5400, 1 }, /* 4320 Mb/s */
 605                 { 2700, 2 }, /* 4320 Mb/s */
 606                 { 1620, 2 }, /* 2592 Mb/s */
 607                 { 2700, 1 }, /* 2160 Mb/s */
 608                 { 1620, 1 }, /* 1296 Mb/s */
 609         };
 610         unsigned int i;
 611
 612         /*
 613          * Find a combination that can fit into max_bw and does not
 614          * exceed the maximum rate and lanes supported by the DP OUT and
 615          * DP IN adapters.
 616          */
 617         for (i = 0; i < ARRAY_SIZE(dp_bw); i++) {
 618                 if (dp_bw[i][0] > out_rate || dp_bw[i][1] > out_lanes)
 619                         continue;
 620
 621                 if (dp_bw[i][0] > in_rate || dp_bw[i][1] > in_lanes)
 622                         continue;
 623
 624                 if (tb_dp_bandwidth(dp_bw[i][0], dp_bw[i][1]) <= max_bw) {
 625                         *new_rate = dp_bw[i][0];
 626                         *new_lanes = dp_bw[i][1];
 627                         return 0;
 628                 }
 629         }
 630
 631         return -ENOSR;
 632 }
 633
 634 static int tb_dp_xchg_caps(struct tb_tunnel *tunnel)
 635 {
 636         u32 out_dp_cap, out_rate, out_lanes, in_dp_cap, in_rate, in_lanes, bw;
 637         struct tb_port *out = tunnel->dst_port;
 638         struct tb_port *in = tunnel->src_port;
 639         int ret, max_bw;
 640
 641         /*
 642          * Copy DP_LOCAL_CAP register to DP_REMOTE_CAP register for
 643          * newer generation hardware.
 644          */
 645         if (in->sw->generation < 2 || out->sw->generation < 2)
 646                 return 0;
 647
 648         /*
 649          * Perform connection manager handshake between IN and OUT ports
 650          * before capabilities exchange can take place.
 651          */
 652         ret = tb_dp_cm_handshake(in, out, 3000);
 653         if (ret)
 654                 return ret;
 655
 656         /* Read both DP_LOCAL_CAP registers */
 657         ret = tb_port_read(in, &in_dp_cap, TB_CFG_PORT,
 658                            in->cap_adap + DP_LOCAL_CAP, 1);
 659         if (ret)
 660                 return ret;
 661
 662         ret = tb_port_read(out, &out_dp_cap, TB_CFG_PORT,
 663                            out->cap_adap + DP_LOCAL_CAP, 1);
 664         if (ret)
 665                 return ret;
 666
 667         /* Write IN local caps to OUT remote caps */
 668         ret = tb_port_write(out, &in_dp_cap, TB_CFG_PORT,
 669                             out->cap_adap + DP_REMOTE_CAP, 1);
 670         if (ret)
 671                 return ret;
 672
 673         in_rate = tb_dp_cap_get_rate(in_dp_cap);
 674         in_lanes = tb_dp_cap_get_lanes(in_dp_cap);
 675         tb_tunnel_dbg(tunnel,
 676                       "DP IN maximum supported bandwidth %u Mb/s x%u = %u Mb/s\n",
 677                       in_rate, in_lanes, tb_dp_bandwidth(in_rate, in_lanes));
 678
 679         /*
 680          * If the tunnel bandwidth is limited (max_bw is set) then see
 681          * if we need to reduce bandwidth to fit there.
 682          */
 683         out_rate = tb_dp_cap_get_rate(out_dp_cap);
 684         out_lanes = tb_dp_cap_get_lanes(out_dp_cap);
 685         bw = tb_dp_bandwidth(out_rate, out_lanes);
 686         tb_tunnel_dbg(tunnel,
 687                       "DP OUT maximum supported bandwidth %u Mb/s x%u = %u Mb/s\n",
 688                       out_rate, out_lanes, bw);
 689
 690         if (tb_port_path_direction_downstream(in, out))
 691                 max_bw = tunnel->max_down;
 692         else
 693                 max_bw = tunnel->max_up;
 694
 695         if (max_bw && bw > max_bw) {
 696                 u32 new_rate, new_lanes, new_bw;
 697
 698                 ret = tb_dp_reduce_bandwidth(max_bw, in_rate, in_lanes,
 699                                              out_rate, out_lanes, &new_rate,
 700                                              &new_lanes);
 701                 if (ret) {
 702                         tb_tunnel_info(tunnel, "not enough bandwidth\n");
 703                         return ret;
 704                 }
 705
 706                 new_bw = tb_dp_bandwidth(new_rate, new_lanes);
 707                 tb_tunnel_dbg(tunnel,
 708                               "bandwidth reduced to %u Mb/s x%u = %u Mb/s\n",
 709                               new_rate, new_lanes, new_bw);
 710
 711                 /*
 712                  * Set new rate and number of lanes before writing it to
 713                  * the IN port remote caps.
 714                  */
 715                 out_dp_cap = tb_dp_cap_set_rate(out_dp_cap, new_rate);
 716                 out_dp_cap = tb_dp_cap_set_lanes(out_dp_cap, new_lanes);
 717         }
 718
 719         /*
 720          * Titan Ridge does not disable AUX timers when it gets
 721          * SET_CONFIG with SET_LTTPR_MODE set. This causes problems with
 722          * DP tunneling.
 723          */
 724         if (tb_route(out->sw) && tb_switch_is_titan_ridge(out->sw)) {
 725                 out_dp_cap |= DP_COMMON_CAP_LTTPR_NS;
 726                 tb_tunnel_dbg(tunnel, "disabling LTTPR\n");
 727         }
 728
 729         return tb_port_write(in, &out_dp_cap, TB_CFG_PORT,
 730                              in->cap_adap + DP_REMOTE_CAP, 1);
 731 }
 732
 733 static int tb_dp_bandwidth_alloc_mode_enable(struct tb_tunnel *tunnel)
 734 {
 735         int ret, estimated_bw, granularity, tmp;
 736         struct tb_port *out = tunnel->dst_port;
 737         struct tb_port *in = tunnel->src_port;
 738         u32 out_dp_cap, out_rate, out_lanes;
 739         u32 in_dp_cap, in_rate, in_lanes;
 740         u32 rate, lanes;
 741
 742         if (!bw_alloc_mode)
 743                 return 0;
 744
 745         ret = usb4_dp_port_set_cm_bandwidth_mode_supported(in, true);
 746         if (ret)
 747                 return ret;
 748
 749         ret = usb4_dp_port_set_group_id(in, in->group->index);
 750         if (ret)
 751                 return ret;
 752
 753         /*
 754          * Get the non-reduced rate and lanes based on the lowest
 755          * capability of both adapters.
 756          */
 757         ret = tb_port_read(in, &in_dp_cap, TB_CFG_PORT,
 758                            in->cap_adap + DP_LOCAL_CAP, 1);
 759         if (ret)
 760                 return ret;
 761
 762         ret = tb_port_read(out, &out_dp_cap, TB_CFG_PORT,
 763                            out->cap_adap + DP_LOCAL_CAP, 1);
 764         if (ret)
 765                 return ret;
 766
 767         in_rate = tb_dp_cap_get_rate(in_dp_cap);
 768         in_lanes = tb_dp_cap_get_lanes(in_dp_cap);
 769         out_rate = tb_dp_cap_get_rate(out_dp_cap);
 770         out_lanes = tb_dp_cap_get_lanes(out_dp_cap);
 771
 772         rate = min(in_rate, out_rate);
 773         lanes = min(in_lanes, out_lanes);
 774         tmp = tb_dp_bandwidth(rate, lanes);
 775
 776         tb_tunnel_dbg(tunnel, "non-reduced bandwidth %u Mb/s x%u = %u Mb/s\n",
 777                       rate, lanes, tmp);
 778
 779         ret = usb4_dp_port_set_nrd(in, rate, lanes);
 780         if (ret)
 781                 return ret;
 782
 783         /*
 784          * Pick up granularity that supports maximum possible bandwidth.
 785          * For that we use the UHBR rates too.
 786          */
 787         in_rate = tb_dp_cap_get_rate_ext(in_dp_cap);
 788         out_rate = tb_dp_cap_get_rate_ext(out_dp_cap);
 789         rate = min(in_rate, out_rate);
 790         tmp = tb_dp_bandwidth(rate, lanes);
 791
 792         tb_tunnel_dbg(tunnel,
 793                       "maximum bandwidth through allocation mode %u Mb/s x%u = %u Mb/s\n",
 794                       rate, lanes, tmp);
 795
 796         for (granularity = 250; tmp / granularity > 255 && granularity <= 1000;
 797              granularity *= 2)
 798                 ;
 799
 800         tb_tunnel_dbg(tunnel, "granularity %d Mb/s\n", granularity);
 801
 802         /*
 803          * Returns -EINVAL if granularity above is outside of the
 804          * accepted ranges.
 805          */
 806         ret = usb4_dp_port_set_granularity(in, granularity);
 807         if (ret)
 808                 return ret;
 809
 810         /*
 811          * Bandwidth estimation is pretty much what we have in
 812          * max_up/down fields. For discovery we just read what the
 813          * estimation was set to.
 814          */
 815         if (tb_port_path_direction_downstream(in, out))
 816                 estimated_bw = tunnel->max_down;
 817         else
 818                 estimated_bw = tunnel->max_up;
 819
 820         tb_tunnel_dbg(tunnel, "estimated bandwidth %d Mb/s\n", estimated_bw);
 821
 822         ret = usb4_dp_port_set_estimated_bandwidth(in, estimated_bw);
 823         if (ret)
 824                 return ret;
 825
 826         /* Initial allocation should be 0 according the spec */
 827         ret = usb4_dp_port_allocate_bandwidth(in, 0);
 828         if (ret)
 829                 return ret;
 830
 831         tb_tunnel_dbg(tunnel, "bandwidth allocation mode enabled\n");
 832         return 0;
 833 }
 834
 835 static int tb_dp_init(struct tb_tunnel *tunnel)
 836 {
 837         struct tb_port *in = tunnel->src_port;
 838         struct tb_switch *sw = in->sw;
 839         struct tb *tb = in->sw->tb;
 840         int ret;
 841
 842         ret = tb_dp_xchg_caps(tunnel);
 843         if (ret)
 844                 return ret;
 845
 846         if (!tb_switch_is_usb4(sw))
 847                 return 0;
 848
 849         if (!usb4_dp_port_bandwidth_mode_supported(in))
 850                 return 0;
 851
 852         tb_tunnel_dbg(tunnel, "bandwidth allocation mode supported\n");
 853
 854         ret = usb4_dp_port_set_cm_id(in, tb->index);
 855         if (ret)
 856                 return ret;
 857
 858         return tb_dp_bandwidth_alloc_mode_enable(tunnel);
 859 }
 860
 861 static void tb_dp_deinit(struct tb_tunnel *tunnel)
 862 {
 863         struct tb_port *in = tunnel->src_port;
 864
 865         if (!usb4_dp_port_bandwidth_mode_supported(in))
 866                 return;
 867         if (usb4_dp_port_bandwidth_mode_enabled(in)) {
 868                 usb4_dp_port_set_cm_bandwidth_mode_supported(in, false);
 869                 tb_tunnel_dbg(tunnel, "bandwidth allocation mode disabled\n");
 870         }
 871 }
 872
 873 static int tb_dp_activate(struct tb_tunnel *tunnel, bool active)
 874 {
 875         int ret;
 876
 877         if (active) {
 878                 struct tb_path **paths;
 879                 int last;
 880
 881                 paths = tunnel->paths;
 882                 last = paths[TB_DP_VIDEO_PATH_OUT]->path_length - 1;
 883
 884                 tb_dp_port_set_hops(tunnel->src_port,
 885                         paths[TB_DP_VIDEO_PATH_OUT]->hops[0].in_hop_index,
 886                         paths[TB_DP_AUX_PATH_OUT]->hops[0].in_hop_index,
 887                         paths[TB_DP_AUX_PATH_IN]->hops[last].next_hop_index);
 888
 889                 tb_dp_port_set_hops(tunnel->dst_port,
 890                         paths[TB_DP_VIDEO_PATH_OUT]->hops[last].next_hop_index,
 891                         paths[TB_DP_AUX_PATH_IN]->hops[0].in_hop_index,
 892                         paths[TB_DP_AUX_PATH_OUT]->hops[last].next_hop_index);
 893         } else {
 894                 tb_dp_port_hpd_clear(tunnel->src_port);
 895                 tb_dp_port_set_hops(tunnel->src_port, 0, 0, 0);
 896                 if (tb_port_is_dpout(tunnel->dst_port))
 897                         tb_dp_port_set_hops(tunnel->dst_port, 0, 0, 0);
 898         }
 899
 900         ret = tb_dp_port_enable(tunnel->src_port, active);
 901         if (ret)
 902                 return ret;
 903
 904         if (tb_port_is_dpout(tunnel->dst_port))
 905                 return tb_dp_port_enable(tunnel->dst_port, active);
 906
 907         return 0;
 908 }
 909
 910 /* max_bw is rounded up to next granularity */
 911 static int tb_dp_bandwidth_mode_maximum_bandwidth(struct tb_tunnel *tunnel,
 912                                                   int *max_bw)
 913 {
 914         struct tb_port *in = tunnel->src_port;
 915         int ret, rate, lanes, nrd_bw;
 916         u32 cap;
 917
 918         /*
 919          * DP IN adapter DP_LOCAL_CAP gets updated to the lowest AUX
 920          * read parameter values so this so we can use this to determine
 921          * the maximum possible bandwidth over this link.
 922          *
 923          * See USB4 v2 spec 1.0 10.4.4.5.
 924          */
 925         ret = tb_port_read(in, &cap, TB_CFG_PORT,
 926                            in->cap_adap + DP_LOCAL_CAP, 1);
 927         if (ret)
 928                 return ret;
 929
 930         rate = tb_dp_cap_get_rate_ext(cap);
 931         if (tb_dp_is_uhbr_rate(rate)) {
 932                 /*
 933                  * When UHBR is used there is no reduction in lanes so
 934                  * we can use this directly.
 935                  */
 936                 lanes = tb_dp_cap_get_lanes(cap);
 937         } else {
 938                 /*
 939                  * If there is no UHBR supported then check the
 940                  * non-reduced rate and lanes.
 941                  */
 942                 ret = usb4_dp_port_nrd(in, &rate, &lanes);
 943                 if (ret)
 944                         return ret;
 945         }
 946
 947         nrd_bw = tb_dp_bandwidth(rate, lanes);
 948
 949         if (max_bw) {
 950                 ret = usb4_dp_port_granularity(in);
 951                 if (ret < 0)
 952                         return ret;
 953                 *max_bw = roundup(nrd_bw, ret);
 954         }
 955
 956         return nrd_bw;
 957 }
 958
 959 static int tb_dp_bandwidth_mode_consumed_bandwidth(struct tb_tunnel *tunnel,
 960                                                    int *consumed_up,
 961                                                    int *consumed_down)
 962 {
 963         struct tb_port *out = tunnel->dst_port;
 964         struct tb_port *in = tunnel->src_port;
 965         int ret, allocated_bw, max_bw;
 966
 967         if (!usb4_dp_port_bandwidth_mode_enabled(in))
 968                 return -EOPNOTSUPP;
 969
 970         if (!tunnel->bw_mode)
 971                 return -EOPNOTSUPP;
 972
 973         /* Read what was allocated previously if any */
 974         ret = usb4_dp_port_allocated_bandwidth(in);
 975         if (ret < 0)
 976                 return ret;
 977         allocated_bw = ret;
 978
 979         ret = tb_dp_bandwidth_mode_maximum_bandwidth(tunnel, &max_bw);
 980         if (ret < 0)
 981                 return ret;
 982         if (allocated_bw == max_bw)
 983                 allocated_bw = ret;
 984
 985         if (tb_port_path_direction_downstream(in, out)) {
 986                 *consumed_up = 0;
 987                 *consumed_down = allocated_bw;
 988         } else {
 989                 *consumed_up = allocated_bw;
 990                 *consumed_down = 0;
 991         }
 992
 993         return 0;
 994 }
 995
 996 static int tb_dp_allocated_bandwidth(struct tb_tunnel *tunnel, int *allocated_up,
 997                                      int *allocated_down)
 998 {
 999         struct tb_port *out = tunnel->dst_port;
1000         struct tb_port *in = tunnel->src_port;
1001
1002         /*
1003          * If we have already set the allocated bandwidth then use that.
1004          * Otherwise we read it from the DPRX.
1005          */
1006         if (usb4_dp_port_bandwidth_mode_enabled(in) && tunnel->bw_mode) {
1007                 int ret, allocated_bw, max_bw;
1008
1009                 ret = usb4_dp_port_allocated_bandwidth(in);
1010                 if (ret < 0)
1011                         return ret;
1012                 allocated_bw = ret;
1013
1014                 ret = tb_dp_bandwidth_mode_maximum_bandwidth(tunnel, &max_bw);
1015                 if (ret < 0)
1016                         return ret;
1017                 if (allocated_bw == max_bw)
1018                         allocated_bw = ret;
1019
1020                 if (tb_port_path_direction_downstream(in, out)) {
1021                         *allocated_up = 0;
1022                         *allocated_down = allocated_bw;
1023                 } else {
1024                         *allocated_up = allocated_bw;
1025                         *allocated_down = 0;
1026                 }
1027                 return 0;
1028         }
1029
1030         return tunnel->consumed_bandwidth(tunnel, allocated_up,
1031                                           allocated_down);
1032 }
1033
1034 static int tb_dp_alloc_bandwidth(struct tb_tunnel *tunnel, int *alloc_up,
1035                                  int *alloc_down)
1036 {
1037         struct tb_port *out = tunnel->dst_port;
1038         struct tb_port *in = tunnel->src_port;
1039         int max_bw, ret, tmp;
1040
1041         if (!usb4_dp_port_bandwidth_mode_enabled(in))
1042                 return -EOPNOTSUPP;
1043
1044         ret = tb_dp_bandwidth_mode_maximum_bandwidth(tunnel, &max_bw);
1045         if (ret < 0)
1046                 return ret;
1047
1048         if (tb_port_path_direction_downstream(in, out)) {
1049                 tmp = min(*alloc_down, max_bw);
1050                 ret = usb4_dp_port_allocate_bandwidth(in, tmp);
1051                 if (ret)
1052                         return ret;
1053                 *alloc_down = tmp;
1054                 *alloc_up = 0;
1055         } else {
1056                 tmp = min(*alloc_up, max_bw);
1057                 ret = usb4_dp_port_allocate_bandwidth(in, tmp);
1058                 if (ret)
1059                         return ret;
1060                 *alloc_down = 0;
1061                 *alloc_up = tmp;
1062         }
1063
1064         /* Now we can use BW mode registers to figure out the bandwidth */
1065         /* TODO: need to handle discovery too */
1066         tunnel->bw_mode = true;
1067         return 0;
1068 }
1069
1070 static int tb_dp_read_dprx(struct tb_tunnel *tunnel, u32 *rate, u32 *lanes,
1071                            int timeout_msec)
1072 {
1073         ktime_t timeout = ktime_add_ms(ktime_get(), timeout_msec);
1074         struct tb_port *in = tunnel->src_port;
1075
1076         /*
1077          * Wait for DPRX done. Normally it should be already set for
1078          * active tunnel.
1079          */
1080         do {
1081                 u32 val;
1082                 int ret;
1083
1084                 ret = tb_port_read(in, &val, TB_CFG_PORT,
1085                                    in->cap_adap + DP_COMMON_CAP, 1);
1086                 if (ret)
1087                         return ret;
1088
1089                 if (val & DP_COMMON_CAP_DPRX_DONE) {
1090                         *rate = tb_dp_cap_get_rate(val);
1091                         *lanes = tb_dp_cap_get_lanes(val);
1092
1093                         tb_tunnel_dbg(tunnel, "DPRX read done\n");
1094                         return 0;
1095                 }
1096                 usleep_range(100, 150);
1097         } while (ktime_before(ktime_get(), timeout));
1098
1099         return -ETIMEDOUT;
1100 }
1101
1102 /* Read cap from tunnel DP IN */
1103 static int tb_dp_read_cap(struct tb_tunnel *tunnel, unsigned int cap, u32 *rate,
1104                           u32 *lanes)
1105 {
1106         struct tb_port *in = tunnel->src_port;
1107         u32 val;
1108         int ret;
1109
1110         switch (cap) {
1111         case DP_LOCAL_CAP:
1112         case DP_REMOTE_CAP:
1113                 break;
1114
1115         default:
1116                 tb_tunnel_WARN(tunnel, "invalid capability index %#x\n", cap);
1117                 return -EINVAL;
1118         }
1119
1120         /*
1121          * Read from the copied remote cap so that we take into account
1122          * if capabilities were reduced during exchange.
1123          */
1124         ret = tb_port_read(in, &val, TB_CFG_PORT, in->cap_adap + cap, 1);
1125         if (ret)
1126                 return ret;
1127
1128         *rate = tb_dp_cap_get_rate(val);
1129         *lanes = tb_dp_cap_get_lanes(val);
1130         return 0;
1131 }
1132
1133 static int tb_dp_maximum_bandwidth(struct tb_tunnel *tunnel, int *max_up,
1134                                    int *max_down)
1135 {
1136         struct tb_port *in = tunnel->src_port;
1137         int ret;
1138
1139         if (!usb4_dp_port_bandwidth_mode_enabled(in))
1140                 return -EOPNOTSUPP;
1141
1142         ret = tb_dp_bandwidth_mode_maximum_bandwidth(tunnel, NULL);
1143         if (ret < 0)
1144                 return ret;
1145
1146         if (tb_port_path_direction_downstream(in, tunnel->dst_port)) {
1147                 *max_up = 0;
1148                 *max_down = ret;
1149         } else {
1150                 *max_up = ret;
1151                 *max_down = 0;
1152         }
1153
1154         return 0;
1155 }
1156
1157 static int tb_dp_consumed_bandwidth(struct tb_tunnel *tunnel, int *consumed_up,
1158                                     int *consumed_down)
1159 {
1160         struct tb_port *in = tunnel->src_port;
1161         const struct tb_switch *sw = in->sw;
1162         u32 rate = 0, lanes = 0;
1163         int ret;
1164
1165         if (tb_dp_is_usb4(sw)) {
1166                 /*
1167                  * On USB4 routers check if the bandwidth allocation
1168                  * mode is enabled first and then read the bandwidth
1169                  * through those registers.
1170                  */
1171                 ret = tb_dp_bandwidth_mode_consumed_bandwidth(tunnel, consumed_up,
1172                                                               consumed_down);
1173                 if (ret < 0) {
1174                         if (ret != -EOPNOTSUPP)
1175                                 return ret;
1176                 } else if (!ret) {
1177                         return 0;
1178                 }
1179                 /*
1180                  * Then see if the DPRX negotiation is ready and if yes
1181                  * return that bandwidth (it may be smaller than the
1182                  * reduced one). Otherwise return the remote (possibly
1183                  * reduced) caps.
1184                  */
1185                 ret = tb_dp_read_dprx(tunnel, &rate, &lanes, 150);
1186                 if (ret) {
1187                         if (ret == -ETIMEDOUT)
1188                                 ret = tb_dp_read_cap(tunnel, DP_REMOTE_CAP,
1189                                                      &rate, &lanes);
1190                         if (ret)
1191                                 return ret;
1192                 }
1193         } else if (sw->generation >= 2) {
1194                 ret = tb_dp_read_cap(tunnel, DP_REMOTE_CAP, &rate, &lanes);
1195                 if (ret)
1196                         return ret;
1197         } else {
1198                 /* No bandwidth management for legacy devices  */
1199                 *consumed_up = 0;
1200                 *consumed_down = 0;
1201                 return 0;
1202         }
1203
1204         if (tb_port_path_direction_downstream(in, tunnel->dst_port)) {
1205                 *consumed_up = 0;
1206                 *consumed_down = tb_dp_bandwidth(rate, lanes);
1207         } else {
1208                 *consumed_up = tb_dp_bandwidth(rate, lanes);
1209                 *consumed_down = 0;
1210         }
1211
1212         return 0;
1213 }
1214
1215 static void tb_dp_init_aux_credits(struct tb_path_hop *hop)
1216 {
1217         struct tb_port *port = hop->in_port;
1218         struct tb_switch *sw = port->sw;
1219
1220         if (tb_port_use_credit_allocation(port))
1221                 hop->initial_credits = sw->min_dp_aux_credits;
1222         else
1223                 hop->initial_credits = 1;
1224 }
1225
1226 static void tb_dp_init_aux_path(struct tb_path *path, bool pm_support)
1227 {
1228         struct tb_path_hop *hop;
1229
1230         path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
1231         path->egress_shared_buffer = TB_PATH_NONE;
1232         path->ingress_fc_enable = TB_PATH_ALL;
1233         path->ingress_shared_buffer = TB_PATH_NONE;
1234         path->priority = TB_DP_AUX_PRIORITY;
1235         path->weight = TB_DP_AUX_WEIGHT;
1236
1237         tb_path_for_each_hop(path, hop) {
1238                 tb_dp_init_aux_credits(hop);
1239                 if (pm_support)
1240                         tb_init_pm_support(hop);
1241         }
1242 }
1243
1244 static int tb_dp_init_video_credits(struct tb_path_hop *hop)
1245 {
1246         struct tb_port *port = hop->in_port;
1247         struct tb_switch *sw = port->sw;
1248
1249         if (tb_port_use_credit_allocation(port)) {
1250                 unsigned int nfc_credits;
1251                 size_t max_dp_streams;
1252
1253                 tb_available_credits(port, &max_dp_streams);
1254                 /*
1255                  * Read the number of currently allocated NFC credits
1256                  * from the lane adapter. Since we only use them for DP
1257                  * tunneling we can use that to figure out how many DP
1258                  * tunnels already go through the lane adapter.
1259                  */
1260                 nfc_credits = port->config.nfc_credits &
1261                                 ADP_CS_4_NFC_BUFFERS_MASK;
1262                 if (nfc_credits / sw->min_dp_main_credits > max_dp_streams)
1263                         return -ENOSPC;
1264
1265                 hop->nfc_credits = sw->min_dp_main_credits;
1266         } else {
1267                 hop->nfc_credits = min(port->total_credits - 2, 12U);
1268         }
1269
1270         return 0;
1271 }
1272
1273 static int tb_dp_init_video_path(struct tb_path *path, bool pm_support)
1274 {
1275         struct tb_path_hop *hop;
1276
1277         path->egress_fc_enable = TB_PATH_NONE;
1278         path->egress_shared_buffer = TB_PATH_NONE;
1279         path->ingress_fc_enable = TB_PATH_NONE;
1280         path->ingress_shared_buffer = TB_PATH_NONE;
1281         path->priority = TB_DP_VIDEO_PRIORITY;
1282         path->weight = TB_DP_VIDEO_WEIGHT;
1283
1284         tb_path_for_each_hop(path, hop) {
1285                 int ret;
1286
1287                 ret = tb_dp_init_video_credits(hop);
1288                 if (ret)
1289                         return ret;
1290                 if (pm_support)
1291                         tb_init_pm_support(hop);
1292         }
1293
1294         return 0;
1295 }
1296
1297 static void tb_dp_dump(struct tb_tunnel *tunnel)
1298 {
1299         struct tb_port *in, *out;
1300         u32 dp_cap, rate, lanes;
1301
1302         in = tunnel->src_port;
1303         out = tunnel->dst_port;
1304
1305         if (tb_port_read(in, &dp_cap, TB_CFG_PORT,
1306                          in->cap_adap + DP_LOCAL_CAP, 1))
1307                 return;
1308
1309         rate = tb_dp_cap_get_rate(dp_cap);
1310         lanes = tb_dp_cap_get_lanes(dp_cap);
1311
1312         tb_tunnel_dbg(tunnel,
1313                       "DP IN maximum supported bandwidth %u Mb/s x%u = %u Mb/s\n",
1314                       rate, lanes, tb_dp_bandwidth(rate, lanes));
1315
1316         out = tunnel->dst_port;
1317
1318         if (tb_port_read(out, &dp_cap, TB_CFG_PORT,
1319                          out->cap_adap + DP_LOCAL_CAP, 1))
1320                 return;
1321
1322         rate = tb_dp_cap_get_rate(dp_cap);
1323         lanes = tb_dp_cap_get_lanes(dp_cap);
1324
1325         tb_tunnel_dbg(tunnel,
1326                       "DP OUT maximum supported bandwidth %u Mb/s x%u = %u Mb/s\n",
1327                       rate, lanes, tb_dp_bandwidth(rate, lanes));
1328
1329         if (tb_port_read(in, &dp_cap, TB_CFG_PORT,
1330                          in->cap_adap + DP_REMOTE_CAP, 1))
1331                 return;
1332
1333         rate = tb_dp_cap_get_rate(dp_cap);
1334         lanes = tb_dp_cap_get_lanes(dp_cap);
1335
1336         tb_tunnel_dbg(tunnel, "reduced bandwidth %u Mb/s x%u = %u Mb/s\n",
1337                       rate, lanes, tb_dp_bandwidth(rate, lanes));
1338 }
1339
1340 /**
1341  * tb_tunnel_discover_dp() - Discover existing Display Port tunnels
1342  * @tb: Pointer to the domain structure
1343  * @in: DP in adapter
1344  * @alloc_hopid: Allocate HopIDs from visited ports
1345  *
1346  * If @in adapter is active, follows the tunnel to the DP out adapter
1347  * and back. Returns the discovered tunnel or %NULL if there was no
1348  * tunnel.
1349  *
1350  * Return: DP tunnel or %NULL if no tunnel found.
1351  */
1352 struct tb_tunnel *tb_tunnel_discover_dp(struct tb *tb, struct tb_port *in,
1353                                         bool alloc_hopid)
1354 {
1355         struct tb_tunnel *tunnel;
1356         struct tb_port *port;
1357         struct tb_path *path;
1358
1359         if (!tb_dp_port_is_enabled(in))
1360                 return NULL;
1361
1362         tunnel = tb_tunnel_alloc(tb, 3, TB_TUNNEL_DP);
1363         if (!tunnel)
1364                 return NULL;
1365
1366         tunnel->init = tb_dp_init;
1367         tunnel->deinit = tb_dp_deinit;
1368         tunnel->activate = tb_dp_activate;
1369         tunnel->maximum_bandwidth = tb_dp_maximum_bandwidth;
1370         tunnel->allocated_bandwidth = tb_dp_allocated_bandwidth;
1371         tunnel->alloc_bandwidth = tb_dp_alloc_bandwidth;
1372         tunnel->consumed_bandwidth = tb_dp_consumed_bandwidth;
1373         tunnel->src_port = in;
1374
1375         path = tb_path_discover(in, TB_DP_VIDEO_HOPID, NULL, -1,
1376                                 &tunnel->dst_port, "Video", alloc_hopid);
1377         if (!path) {
1378                 /* Just disable the DP IN port */
1379                 tb_dp_port_enable(in, false);
1380                 goto err_free;
1381         }
1382         tunnel->paths[TB_DP_VIDEO_PATH_OUT] = path;
1383         if (tb_dp_init_video_path(tunnel->paths[TB_DP_VIDEO_PATH_OUT], false))
1384                 goto err_free;
1385
1386         path = tb_path_discover(in, TB_DP_AUX_TX_HOPID, NULL, -1, NULL, "AUX TX",
1387                                 alloc_hopid);
1388         if (!path)
1389                 goto err_deactivate;
1390         tunnel->paths[TB_DP_AUX_PATH_OUT] = path;
1391         tb_dp_init_aux_path(tunnel->paths[TB_DP_AUX_PATH_OUT], false);
1392
1393         path = tb_path_discover(tunnel->dst_port, -1, in, TB_DP_AUX_RX_HOPID,
1394                                 &port, "AUX RX", alloc_hopid);
1395         if (!path)
1396                 goto err_deactivate;
1397         tunnel->paths[TB_DP_AUX_PATH_IN] = path;
1398         tb_dp_init_aux_path(tunnel->paths[TB_DP_AUX_PATH_IN], false);
1399
1400         /* Validate that the tunnel is complete */
1401         if (!tb_port_is_dpout(tunnel->dst_port)) {
1402                 tb_port_warn(in, "path does not end on a DP adapter, cleaning up\n");
1403                 goto err_deactivate;
1404         }
1405
1406         if (!tb_dp_port_is_enabled(tunnel->dst_port))
1407                 goto err_deactivate;
1408
1409         if (!tb_dp_port_hpd_is_active(tunnel->dst_port))
1410                 goto err_deactivate;
1411
1412         if (port != tunnel->src_port) {
1413                 tb_tunnel_warn(tunnel, "path is not complete, cleaning up\n");
1414                 goto err_deactivate;
1415         }
1416
1417         tb_dp_dump(tunnel);
1418
1419         tb_tunnel_dbg(tunnel, "discovered\n");
1420         return tunnel;
1421
1422 err_deactivate:
1423         tb_tunnel_deactivate(tunnel);
1424 err_free:
1425         tb_tunnel_free(tunnel);
1426
1427         return NULL;
1428 }
1429
1430 /**
1431  * tb_tunnel_alloc_dp() - allocate a Display Port tunnel
1432  * @tb: Pointer to the domain structure
1433  * @in: DP in adapter port
1434  * @out: DP out adapter port
1435  * @link_nr: Preferred lane adapter when the link is not bonded
1436  * @max_up: Maximum available upstream bandwidth for the DP tunnel (%0
1437  *          if not limited)
1438  * @max_down: Maximum available downstream bandwidth for the DP tunnel
1439  *            (%0 if not limited)
1440  *
1441  * Allocates a tunnel between @in and @out that is capable of tunneling
1442  * Display Port traffic.
1443  *
1444  * Return: Returns a tb_tunnel on success or NULL on failure.
1445  */
1446 struct tb_tunnel *tb_tunnel_alloc_dp(struct tb *tb, struct tb_port *in,
1447                                      struct tb_port *out, int link_nr,
1448                                      int max_up, int max_down)
1449 {
1450         struct tb_tunnel *tunnel;
1451         struct tb_path **paths;
1452         struct tb_path *path;
1453         bool pm_support;
1454
1455         if (WARN_ON(!in->cap_adap || !out->cap_adap))
1456                 return NULL;
1457
1458         tunnel = tb_tunnel_alloc(tb, 3, TB_TUNNEL_DP);
1459         if (!tunnel)
1460                 return NULL;
1461
1462         tunnel->init = tb_dp_init;
1463         tunnel->deinit = tb_dp_deinit;
1464         tunnel->activate = tb_dp_activate;
1465         tunnel->maximum_bandwidth = tb_dp_maximum_bandwidth;
1466         tunnel->allocated_bandwidth = tb_dp_allocated_bandwidth;
1467         tunnel->alloc_bandwidth = tb_dp_alloc_bandwidth;
1468         tunnel->consumed_bandwidth = tb_dp_consumed_bandwidth;
1469         tunnel->src_port = in;
1470         tunnel->dst_port = out;
1471         tunnel->max_up = max_up;
1472         tunnel->max_down = max_down;
1473
1474         paths = tunnel->paths;
1475         pm_support = usb4_switch_version(in->sw) >= 2;
1476
1477         path = tb_path_alloc(tb, in, TB_DP_VIDEO_HOPID, out, TB_DP_VIDEO_HOPID,
1478                              link_nr, "Video");
1479         if (!path)
1480                 goto err_free;
1481         tb_dp_init_video_path(path, pm_support);
1482         paths[TB_DP_VIDEO_PATH_OUT] = path;
1483
1484         path = tb_path_alloc(tb, in, TB_DP_AUX_TX_HOPID, out,
1485                              TB_DP_AUX_TX_HOPID, link_nr, "AUX TX");
1486         if (!path)
1487                 goto err_free;
1488         tb_dp_init_aux_path(path, pm_support);
1489         paths[TB_DP_AUX_PATH_OUT] = path;
1490
1491         path = tb_path_alloc(tb, out, TB_DP_AUX_RX_HOPID, in,
1492                              TB_DP_AUX_RX_HOPID, link_nr, "AUX RX");
1493         if (!path)
1494                 goto err_free;
1495         tb_dp_init_aux_path(path, pm_support);
1496         paths[TB_DP_AUX_PATH_IN] = path;
1497
1498         return tunnel;
1499
1500 err_free:
1501         tb_tunnel_free(tunnel);
1502         return NULL;
1503 }
1504
1505 static unsigned int tb_dma_available_credits(const struct tb_port *port)
1506 {
1507         const struct tb_switch *sw = port->sw;
1508         int credits;
1509
1510         credits = tb_available_credits(port, NULL);
1511         if (tb_acpi_may_tunnel_pcie())
1512                 credits -= sw->max_pcie_credits;
1513         credits -= port->dma_credits;
1514
1515         return credits > 0 ? credits : 0;
1516 }
1517
1518 static int tb_dma_reserve_credits(struct tb_path_hop *hop, unsigned int credits)
1519 {
1520         struct tb_port *port = hop->in_port;
1521
1522         if (tb_port_use_credit_allocation(port)) {
1523                 unsigned int available = tb_dma_available_credits(port);
1524
1525                 /*
1526                  * Need to have at least TB_MIN_DMA_CREDITS, otherwise
1527                  * DMA path cannot be established.
1528                  */
1529                 if (available < TB_MIN_DMA_CREDITS)
1530                         return -ENOSPC;
1531
1532                 while (credits > available)
1533                         credits--;
1534
1535                 tb_port_dbg(port, "reserving %u credits for DMA path\n",
1536                             credits);
1537
1538                 port->dma_credits += credits;
1539         } else {
1540                 if (tb_port_is_null(port))
1541                         credits = port->bonded ? 14 : 6;
1542                 else
1543                         credits = min(port->total_credits, credits);
1544         }
1545
1546         hop->initial_credits = credits;
1547         return 0;
1548 }
1549
1550 /* Path from lane adapter to NHI */
1551 static int tb_dma_init_rx_path(struct tb_path *path, unsigned int credits)
1552 {
1553         struct tb_path_hop *hop;
1554         unsigned int i, tmp;
1555
1556         path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
1557         path->ingress_fc_enable = TB_PATH_ALL;
1558         path->egress_shared_buffer = TB_PATH_NONE;
1559         path->ingress_shared_buffer = TB_PATH_NONE;
1560         path->priority = TB_DMA_PRIORITY;
1561         path->weight = TB_DMA_WEIGHT;
1562         path->clear_fc = true;
1563
1564         /*
1565          * First lane adapter is the one connected to the remote host.
1566          * We don't tunnel other traffic over this link so can use all
1567          * the credits (except the ones reserved for control traffic).
1568          */
1569         hop = &path->hops[0];
1570         tmp = min(tb_usable_credits(hop->in_port), credits);
1571         hop->initial_credits = tmp;
1572         hop->in_port->dma_credits += tmp;
1573
1574         for (i = 1; i < path->path_length; i++) {
1575                 int ret;
1576
1577                 ret = tb_dma_reserve_credits(&path->hops[i], credits);
1578                 if (ret)
1579                         return ret;
1580         }
1581
1582         return 0;
1583 }
1584
1585 /* Path from NHI to lane adapter */
1586 static int tb_dma_init_tx_path(struct tb_path *path, unsigned int credits)
1587 {
1588         struct tb_path_hop *hop;
1589
1590         path->egress_fc_enable = TB_PATH_ALL;
1591         path->ingress_fc_enable = TB_PATH_ALL;
1592         path->egress_shared_buffer = TB_PATH_NONE;
1593         path->ingress_shared_buffer = TB_PATH_NONE;
1594         path->priority = TB_DMA_PRIORITY;
1595         path->weight = TB_DMA_WEIGHT;
1596         path->clear_fc = true;
1597
1598         tb_path_for_each_hop(path, hop) {
1599                 int ret;
1600
1601                 ret = tb_dma_reserve_credits(hop, credits);
1602                 if (ret)
1603                         return ret;
1604         }
1605
1606         return 0;
1607 }
1608
1609 static void tb_dma_release_credits(struct tb_path_hop *hop)
1610 {
1611         struct tb_port *port = hop->in_port;
1612
1613         if (tb_port_use_credit_allocation(port)) {
1614                 port->dma_credits -= hop->initial_credits;
1615
1616                 tb_port_dbg(port, "released %u DMA path credits\n",
1617                             hop->initial_credits);
1618         }
1619 }
1620
1621 static void tb_dma_deinit_path(struct tb_path *path)
1622 {
1623         struct tb_path_hop *hop;
1624
1625         tb_path_for_each_hop(path, hop)
1626                 tb_dma_release_credits(hop);
1627 }
1628
1629 static void tb_dma_deinit(struct tb_tunnel *tunnel)
1630 {
1631         int i;
1632
1633         for (i = 0; i < tunnel->npaths; i++) {
1634                 if (!tunnel->paths[i])
1635                         continue;
1636                 tb_dma_deinit_path(tunnel->paths[i]);
1637         }
1638 }
1639
1640 /**
1641  * tb_tunnel_alloc_dma() - allocate a DMA tunnel
1642  * @tb: Pointer to the domain structure
1643  * @nhi: Host controller port
1644  * @dst: Destination null port which the other domain is connected to
1645  * @transmit_path: HopID used for transmitting packets
1646  * @transmit_ring: NHI ring number used to send packets towards the
1647  *                 other domain. Set to %-1 if TX path is not needed.
1648  * @receive_path: HopID used for receiving packets
1649  * @receive_ring: NHI ring number used to receive packets from the
1650  *                other domain. Set to %-1 if RX path is not needed.
1651  *
1652  * Return: Returns a tb_tunnel on success or NULL on failure.
1653  */
1654 struct tb_tunnel *tb_tunnel_alloc_dma(struct tb *tb, struct tb_port *nhi,
1655                                       struct tb_port *dst, int transmit_path,
1656                                       int transmit_ring, int receive_path,
1657                                       int receive_ring)
1658 {
1659         struct tb_tunnel *tunnel;
1660         size_t npaths = 0, i = 0;
1661         struct tb_path *path;
1662         int credits;
1663
1664         /* Ring 0 is reserved for control channel */
1665         if (WARN_ON(!receive_ring || !transmit_ring))
1666                 return NULL;
1667
1668         if (receive_ring > 0)
1669                 npaths++;
1670         if (transmit_ring > 0)
1671                 npaths++;
1672
1673         if (WARN_ON(!npaths))
1674                 return NULL;
1675
1676         tunnel = tb_tunnel_alloc(tb, npaths, TB_TUNNEL_DMA);
1677         if (!tunnel)
1678                 return NULL;
1679
1680         tunnel->src_port = nhi;
1681         tunnel->dst_port = dst;
1682         tunnel->deinit = tb_dma_deinit;
1683
1684         credits = min_not_zero(dma_credits, nhi->sw->max_dma_credits);
1685
1686         if (receive_ring > 0) {
1687                 path = tb_path_alloc(tb, dst, receive_path, nhi, receive_ring, 0,
1688                                      "DMA RX");
1689                 if (!path)
1690                         goto err_free;
1691                 tunnel->paths[i++] = path;
1692                 if (tb_dma_init_rx_path(path, credits)) {
1693                         tb_tunnel_dbg(tunnel, "not enough buffers for RX path\n");
1694                         goto err_free;
1695                 }
1696         }
1697
1698         if (transmit_ring > 0) {
1699                 path = tb_path_alloc(tb, nhi, transmit_ring, dst, transmit_path, 0,
1700                                      "DMA TX");
1701                 if (!path)
1702                         goto err_free;
1703                 tunnel->paths[i++] = path;
1704                 if (tb_dma_init_tx_path(path, credits)) {
1705                         tb_tunnel_dbg(tunnel, "not enough buffers for TX path\n");
1706                         goto err_free;
1707                 }
1708         }
1709
1710         return tunnel;
1711
1712 err_free:
1713         tb_tunnel_free(tunnel);
1714         return NULL;
1715 }
1716
1717 /**
1718  * tb_tunnel_match_dma() - Match DMA tunnel
1719  * @tunnel: Tunnel to match
1720  * @transmit_path: HopID used for transmitting packets. Pass %-1 to ignore.
1721  * @transmit_ring: NHI ring number used to send packets towards the
1722  *                 other domain. Pass %-1 to ignore.
1723  * @receive_path: HopID used for receiving packets. Pass %-1 to ignore.
1724  * @receive_ring: NHI ring number used to receive packets from the
1725  *                other domain. Pass %-1 to ignore.
1726  *
1727  * This function can be used to match specific DMA tunnel, if there are
1728  * multiple DMA tunnels going through the same XDomain connection.
1729  * Returns true if there is match and false otherwise.
1730  */
1731 bool tb_tunnel_match_dma(const struct tb_tunnel *tunnel, int transmit_path,
1732                          int transmit_ring, int receive_path, int receive_ring)
1733 {
1734         const struct tb_path *tx_path = NULL, *rx_path = NULL;
1735         int i;
1736
1737         if (!receive_ring || !transmit_ring)
1738                 return false;
1739
1740         for (i = 0; i < tunnel->npaths; i++) {
1741                 const struct tb_path *path = tunnel->paths[i];
1742
1743                 if (!path)
1744                         continue;
1745
1746                 if (tb_port_is_nhi(path->hops[0].in_port))
1747                         tx_path = path;
1748                 else if (tb_port_is_nhi(path->hops[path->path_length - 1].out_port))
1749                         rx_path = path;
1750         }
1751
1752         if (transmit_ring > 0 || transmit_path > 0) {
1753                 if (!tx_path)
1754                         return false;
1755                 if (transmit_ring > 0 &&
1756                     (tx_path->hops[0].in_hop_index != transmit_ring))
1757                         return false;
1758                 if (transmit_path > 0 &&
1759                     (tx_path->hops[tx_path->path_length - 1].next_hop_index != transmit_path))
1760                         return false;
1761         }
1762
1763         if (receive_ring > 0 || receive_path > 0) {
1764                 if (!rx_path)
1765                         return false;
1766                 if (receive_path > 0 &&
1767                     (rx_path->hops[0].in_hop_index != receive_path))
1768                         return false;
1769                 if (receive_ring > 0 &&
1770                     (rx_path->hops[rx_path->path_length - 1].next_hop_index != receive_ring))
1771                         return false;
1772         }
1773
1774         return true;
1775 }
1776
1777 static int tb_usb3_max_link_rate(struct tb_port *up, struct tb_port *down)
1778 {
1779         int ret, up_max_rate, down_max_rate;
1780
1781         ret = usb4_usb3_port_max_link_rate(up);
1782         if (ret < 0)
1783                 return ret;
1784         up_max_rate = ret;
1785
1786         ret = usb4_usb3_port_max_link_rate(down);
1787         if (ret < 0)
1788                 return ret;
1789         down_max_rate = ret;
1790
1791         return min(up_max_rate, down_max_rate);
1792 }
1793
1794 static int tb_usb3_init(struct tb_tunnel *tunnel)
1795 {
1796         tb_tunnel_dbg(tunnel, "allocating initial bandwidth %d/%d Mb/s\n",
1797                       tunnel->allocated_up, tunnel->allocated_down);
1798
1799         return usb4_usb3_port_allocate_bandwidth(tunnel->src_port,
1800                                                  &tunnel->allocated_up,
1801                                                  &tunnel->allocated_down);
1802 }
1803
1804 static int tb_usb3_activate(struct tb_tunnel *tunnel, bool activate)
1805 {
1806         int res;
1807
1808         res = tb_usb3_port_enable(tunnel->src_port, activate);
1809         if (res)
1810                 return res;
1811
1812         if (tb_port_is_usb3_up(tunnel->dst_port))
1813                 return tb_usb3_port_enable(tunnel->dst_port, activate);
1814
1815         return 0;
1816 }
1817
1818 static int tb_usb3_consumed_bandwidth(struct tb_tunnel *tunnel,
1819                 int *consumed_up, int *consumed_down)
1820 {
1821         struct tb_port *port = tb_upstream_port(tunnel->dst_port->sw);
1822         int pcie_weight = tb_acpi_may_tunnel_pcie() ? TB_PCI_WEIGHT : 0;
1823
1824         /*
1825          * PCIe tunneling, if enabled, affects the USB3 bandwidth so
1826          * take that it into account here.
1827          */
1828         *consumed_up = tunnel->allocated_up *
1829                 (TB_USB3_WEIGHT + pcie_weight) / TB_USB3_WEIGHT;
1830         *consumed_down = tunnel->allocated_down *
1831                 (TB_USB3_WEIGHT + pcie_weight) / TB_USB3_WEIGHT;
1832
1833         if (tb_port_get_link_generation(port) >= 4) {
1834                 *consumed_up = max(*consumed_up, USB4_V2_USB3_MIN_BANDWIDTH);
1835                 *consumed_down = max(*consumed_down, USB4_V2_USB3_MIN_BANDWIDTH);
1836         }
1837
1838         return 0;
1839 }
1840
1841 static int tb_usb3_release_unused_bandwidth(struct tb_tunnel *tunnel)
1842 {
1843         int ret;
1844
1845         ret = usb4_usb3_port_release_bandwidth(tunnel->src_port,
1846                                                &tunnel->allocated_up,
1847                                                &tunnel->allocated_down);
1848         if (ret)
1849                 return ret;
1850
1851         tb_tunnel_dbg(tunnel, "decreased bandwidth allocation to %d/%d Mb/s\n",
1852                       tunnel->allocated_up, tunnel->allocated_down);
1853         return 0;
1854 }
1855
1856 static void tb_usb3_reclaim_available_bandwidth(struct tb_tunnel *tunnel,
1857                                                 int *available_up,
1858                                                 int *available_down)
1859 {
1860         int ret, max_rate, allocate_up, allocate_down;
1861
1862         ret = tb_usb3_max_link_rate(tunnel->dst_port, tunnel->src_port);
1863         if (ret < 0) {
1864                 tb_tunnel_warn(tunnel, "failed to read maximum link rate\n");
1865                 return;
1866         }
1867
1868         /*
1869          * 90% of the max rate can be allocated for isochronous
1870          * transfers.
1871          */
1872         max_rate = ret * 90 / 100;
1873
1874         /* No need to reclaim if already at maximum */
1875         if (tunnel->allocated_up >= max_rate &&
1876             tunnel->allocated_down >= max_rate)
1877                 return;
1878
1879         /* Don't go lower than what is already allocated */
1880         allocate_up = min(max_rate, *available_up);
1881         if (allocate_up < tunnel->allocated_up)
1882                 allocate_up = tunnel->allocated_up;
1883
1884         allocate_down = min(max_rate, *available_down);
1885         if (allocate_down < tunnel->allocated_down)
1886                 allocate_down = tunnel->allocated_down;
1887
1888         /* If no changes no need to do more */
1889         if (allocate_up == tunnel->allocated_up &&
1890             allocate_down == tunnel->allocated_down)
1891                 return;
1892
1893         ret = usb4_usb3_port_allocate_bandwidth(tunnel->src_port, &allocate_up,
1894                                                 &allocate_down);
1895         if (ret) {
1896                 tb_tunnel_info(tunnel, "failed to allocate bandwidth\n");
1897                 return;
1898         }
1899
1900         tunnel->allocated_up = allocate_up;
1901         *available_up -= tunnel->allocated_up;
1902
1903         tunnel->allocated_down = allocate_down;
1904         *available_down -= tunnel->allocated_down;
1905
1906         tb_tunnel_dbg(tunnel, "increased bandwidth allocation to %d/%d Mb/s\n",
1907                       tunnel->allocated_up, tunnel->allocated_down);
1908 }
1909
1910 static void tb_usb3_init_credits(struct tb_path_hop *hop)
1911 {
1912         struct tb_port *port = hop->in_port;
1913         struct tb_switch *sw = port->sw;
1914         unsigned int credits;
1915
1916         if (tb_port_use_credit_allocation(port)) {
1917                 credits = sw->max_usb3_credits;
1918         } else {
1919                 if (tb_port_is_null(port))
1920                         credits = port->bonded ? 32 : 16;
1921                 else
1922                         credits = 7;
1923         }
1924
1925         hop->initial_credits = credits;
1926 }
1927
1928 static void tb_usb3_init_path(struct tb_path *path)
1929 {
1930         struct tb_path_hop *hop;
1931
1932         path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
1933         path->egress_shared_buffer = TB_PATH_NONE;
1934         path->ingress_fc_enable = TB_PATH_ALL;
1935         path->ingress_shared_buffer = TB_PATH_NONE;
1936         path->priority = TB_USB3_PRIORITY;
1937         path->weight = TB_USB3_WEIGHT;
1938         path->drop_packages = 0;
1939
1940         tb_path_for_each_hop(path, hop)
1941                 tb_usb3_init_credits(hop);
1942 }
1943
1944 /**
1945  * tb_tunnel_discover_usb3() - Discover existing USB3 tunnels
1946  * @tb: Pointer to the domain structure
1947  * @down: USB3 downstream adapter
1948  * @alloc_hopid: Allocate HopIDs from visited ports
1949  *
1950  * If @down adapter is active, follows the tunnel to the USB3 upstream
1951  * adapter and back. Returns the discovered tunnel or %NULL if there was
1952  * no tunnel.
1953  */
1954 struct tb_tunnel *tb_tunnel_discover_usb3(struct tb *tb, struct tb_port *down,
1955                                           bool alloc_hopid)
1956 {
1957         struct tb_tunnel *tunnel;
1958         struct tb_path *path;
1959
1960         if (!tb_usb3_port_is_enabled(down))
1961                 return NULL;
1962
1963         tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_USB3);
1964         if (!tunnel)
1965                 return NULL;
1966
1967         tunnel->activate = tb_usb3_activate;
1968         tunnel->src_port = down;
1969
1970         /*
1971          * Discover both paths even if they are not complete. We will
1972          * clean them up by calling tb_tunnel_deactivate() below in that
1973          * case.
1974          */
1975         path = tb_path_discover(down, TB_USB3_HOPID, NULL, -1,
1976                                 &tunnel->dst_port, "USB3 Down", alloc_hopid);
1977         if (!path) {
1978                 /* Just disable the downstream port */
1979                 tb_usb3_port_enable(down, false);
1980                 goto err_free;
1981         }
1982         tunnel->paths[TB_USB3_PATH_DOWN] = path;
1983         tb_usb3_init_path(tunnel->paths[TB_USB3_PATH_DOWN]);
1984
1985         path = tb_path_discover(tunnel->dst_port, -1, down, TB_USB3_HOPID, NULL,
1986                                 "USB3 Up", alloc_hopid);
1987         if (!path)
1988                 goto err_deactivate;
1989         tunnel->paths[TB_USB3_PATH_UP] = path;
1990         tb_usb3_init_path(tunnel->paths[TB_USB3_PATH_UP]);
1991
1992         /* Validate that the tunnel is complete */
1993         if (!tb_port_is_usb3_up(tunnel->dst_port)) {
1994                 tb_port_warn(tunnel->dst_port,
1995                              "path does not end on an USB3 adapter, cleaning up\n");
1996                 goto err_deactivate;
1997         }
1998
1999         if (down != tunnel->src_port) {
2000                 tb_tunnel_warn(tunnel, "path is not complete, cleaning up\n");
2001                 goto err_deactivate;
2002         }
2003
2004         if (!tb_usb3_port_is_enabled(tunnel->dst_port)) {
2005                 tb_tunnel_warn(tunnel,
2006                                "tunnel is not fully activated, cleaning up\n");
2007                 goto err_deactivate;
2008         }
2009
2010         if (!tb_route(down->sw)) {
2011                 int ret;
2012
2013                 /*
2014                  * Read the initial bandwidth allocation for the first
2015                  * hop tunnel.
2016                  */
2017                 ret = usb4_usb3_port_allocated_bandwidth(down,
2018                         &tunnel->allocated_up, &tunnel->allocated_down);
2019                 if (ret)
2020                         goto err_deactivate;
2021
2022                 tb_tunnel_dbg(tunnel, "currently allocated bandwidth %d/%d Mb/s\n",
2023                               tunnel->allocated_up, tunnel->allocated_down);
2024
2025                 tunnel->init = tb_usb3_init;
2026                 tunnel->consumed_bandwidth = tb_usb3_consumed_bandwidth;
2027                 tunnel->release_unused_bandwidth =
2028                         tb_usb3_release_unused_bandwidth;
2029                 tunnel->reclaim_available_bandwidth =
2030                         tb_usb3_reclaim_available_bandwidth;
2031         }
2032
2033         tb_tunnel_dbg(tunnel, "discovered\n");
2034         return tunnel;
2035
2036 err_deactivate:
2037         tb_tunnel_deactivate(tunnel);
2038 err_free:
2039         tb_tunnel_free(tunnel);
2040
2041         return NULL;
2042 }
2043
2044 /**
2045  * tb_tunnel_alloc_usb3() - allocate a USB3 tunnel
2046  * @tb: Pointer to the domain structure
2047  * @up: USB3 upstream adapter port
2048  * @down: USB3 downstream adapter port
2049  * @max_up: Maximum available upstream bandwidth for the USB3 tunnel (%0
2050  *          if not limited).
2051  * @max_down: Maximum available downstream bandwidth for the USB3 tunnel
2052  *            (%0 if not limited).
2053  *
2054  * Allocate an USB3 tunnel. The ports must be of type @TB_TYPE_USB3_UP and
2055  * @TB_TYPE_USB3_DOWN.
2056  *
2057  * Return: Returns a tb_tunnel on success or %NULL on failure.
2058  */
2059 struct tb_tunnel *tb_tunnel_alloc_usb3(struct tb *tb, struct tb_port *up,
2060                                        struct tb_port *down, int max_up,
2061                                        int max_down)
2062 {
2063         struct tb_tunnel *tunnel;
2064         struct tb_path *path;
2065         int max_rate = 0;
2066
2067         /*
2068          * Check that we have enough bandwidth available for the new
2069          * USB3 tunnel.
2070          */
2071         if (max_up > 0 || max_down > 0) {
2072                 max_rate = tb_usb3_max_link_rate(down, up);
2073                 if (max_rate < 0)
2074                         return NULL;
2075
2076                 /* Only 90% can be allocated for USB3 isochronous transfers */
2077                 max_rate = max_rate * 90 / 100;
2078                 tb_port_dbg(up, "required bandwidth for USB3 tunnel %d Mb/s\n",
2079                             max_rate);
2080
2081                 if (max_rate > max_up || max_rate > max_down) {
2082                         tb_port_warn(up, "not enough bandwidth for USB3 tunnel\n");
2083                         return NULL;
2084                 }
2085         }
2086
2087         tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_USB3);
2088         if (!tunnel)
2089                 return NULL;
2090
2091         tunnel->activate = tb_usb3_activate;
2092         tunnel->src_port = down;
2093         tunnel->dst_port = up;
2094         tunnel->max_up = max_up;
2095         tunnel->max_down = max_down;
2096
2097         path = tb_path_alloc(tb, down, TB_USB3_HOPID, up, TB_USB3_HOPID, 0,
2098                              "USB3 Down");
2099         if (!path) {
2100                 tb_tunnel_free(tunnel);
2101                 return NULL;
2102         }
2103         tb_usb3_init_path(path);
2104         tunnel->paths[TB_USB3_PATH_DOWN] = path;
2105
2106         path = tb_path_alloc(tb, up, TB_USB3_HOPID, down, TB_USB3_HOPID, 0,
2107                              "USB3 Up");
2108         if (!path) {
2109                 tb_tunnel_free(tunnel);
2110                 return NULL;
2111         }
2112         tb_usb3_init_path(path);
2113         tunnel->paths[TB_USB3_PATH_UP] = path;
2114
2115         if (!tb_route(down->sw)) {
2116                 tunnel->allocated_up = max_rate;
2117                 tunnel->allocated_down = max_rate;
2118
2119                 tunnel->init = tb_usb3_init;
2120                 tunnel->consumed_bandwidth = tb_usb3_consumed_bandwidth;
2121                 tunnel->release_unused_bandwidth =
2122                         tb_usb3_release_unused_bandwidth;
2123                 tunnel->reclaim_available_bandwidth =
2124                         tb_usb3_reclaim_available_bandwidth;
2125         }
2126
2127         return tunnel;
2128 }
2129
2130 /**
2131  * tb_tunnel_free() - free a tunnel
2132  * @tunnel: Tunnel to be freed
2133  *
2134  * Frees a tunnel. The tunnel does not need to be deactivated.
2135  */
2136 void tb_tunnel_free(struct tb_tunnel *tunnel)
2137 {
2138         int i;
2139
2140         if (!tunnel)
2141                 return;
2142
2143         if (tunnel->deinit)
2144                 tunnel->deinit(tunnel);
2145
2146         for (i = 0; i < tunnel->npaths; i++) {
2147                 if (tunnel->paths[i])
2148                         tb_path_free(tunnel->paths[i]);
2149         }
2150
2151         kfree(tunnel->paths);
2152         kfree(tunnel);
2153 }
2154
2155 /**
2156  * tb_tunnel_is_invalid - check whether an activated path is still valid
2157  * @tunnel: Tunnel to check
2158  */
2159 bool tb_tunnel_is_invalid(struct tb_tunnel *tunnel)
2160 {
2161         int i;
2162
2163         for (i = 0; i < tunnel->npaths; i++) {
2164                 WARN_ON(!tunnel->paths[i]->activated);
2165                 if (tb_path_is_invalid(tunnel->paths[i]))
2166                         return true;
2167         }
2168
2169         return false;
2170 }
2171
2172 /**
2173  * tb_tunnel_restart() - activate a tunnel after a hardware reset
2174  * @tunnel: Tunnel to restart
2175  *
2176  * Return: 0 on success and negative errno in case if failure
2177  */
2178 int tb_tunnel_restart(struct tb_tunnel *tunnel)
2179 {
2180         int res, i;
2181
2182         tb_tunnel_dbg(tunnel, "activating\n");
2183
2184         /*
2185          * Make sure all paths are properly disabled before enabling
2186          * them again.
2187          */
2188         for (i = 0; i < tunnel->npaths; i++) {
2189                 if (tunnel->paths[i]->activated) {
2190                         tb_path_deactivate(tunnel->paths[i]);
2191                         tunnel->paths[i]->activated = false;
2192                 }
2193         }
2194
2195         if (tunnel->init) {
2196                 res = tunnel->init(tunnel);
2197                 if (res)
2198                         return res;
2199         }
2200
2201         for (i = 0; i < tunnel->npaths; i++) {
2202                 res = tb_path_activate(tunnel->paths[i]);
2203                 if (res)
2204                         goto err;
2205         }
2206
2207         if (tunnel->activate) {
2208                 res = tunnel->activate(tunnel, true);
2209                 if (res)
2210                         goto err;
2211         }
2212
2213         return 0;
2214
2215 err:
2216         tb_tunnel_warn(tunnel, "activation failed\n");
2217         tb_tunnel_deactivate(tunnel);
2218         return res;
2219 }
2220
2221 /**
2222  * tb_tunnel_activate() - activate a tunnel
2223  * @tunnel: Tunnel to activate
2224  *
2225  * Return: Returns 0 on success or an error code on failure.
2226  */
2227 int tb_tunnel_activate(struct tb_tunnel *tunnel)
2228 {
2229         int i;
2230
2231         for (i = 0; i < tunnel->npaths; i++) {
2232                 if (tunnel->paths[i]->activated) {
2233                         tb_tunnel_WARN(tunnel,
2234                                        "trying to activate an already activated tunnel\n");
2235                         return -EINVAL;
2236                 }
2237         }
2238
2239         return tb_tunnel_restart(tunnel);
2240 }
2241
2242 /**
2243  * tb_tunnel_deactivate() - deactivate a tunnel
2244  * @tunnel: Tunnel to deactivate
2245  */
2246 void tb_tunnel_deactivate(struct tb_tunnel *tunnel)
2247 {
2248         int i;
2249
2250         tb_tunnel_dbg(tunnel, "deactivating\n");
2251
2252         if (tunnel->activate)
2253                 tunnel->activate(tunnel, false);
2254
2255         for (i = 0; i < tunnel->npaths; i++) {
2256                 if (tunnel->paths[i] && tunnel->paths[i]->activated)
2257                         tb_path_deactivate(tunnel->paths[i]);
2258         }
2259 }
2260
2261 /**
2262  * tb_tunnel_port_on_path() - Does the tunnel go through port
2263  * @tunnel: Tunnel to check
2264  * @port: Port to check
2265  *
2266  * Returns true if @tunnel goes through @port (direction does not matter),
2267  * false otherwise.
2268  */
2269 bool tb_tunnel_port_on_path(const struct tb_tunnel *tunnel,
2270                             const struct tb_port *port)
2271 {
2272         int i;
2273
2274         for (i = 0; i < tunnel->npaths; i++) {
2275                 if (!tunnel->paths[i])
2276                         continue;
2277
2278                 if (tb_path_port_on_path(tunnel->paths[i], port))
2279                         return true;
2280         }
2281
2282         return false;
2283 }
2284
2285 static bool tb_tunnel_is_active(const struct tb_tunnel *tunnel)
2286 {
2287         int i;
2288
2289         for (i = 0; i < tunnel->npaths; i++) {
2290                 if (!tunnel->paths[i])
2291                         return false;
2292                 if (!tunnel->paths[i]->activated)
2293                         return false;
2294         }
2295
2296         return true;
2297 }
2298
2299 /**
2300  * tb_tunnel_maximum_bandwidth() - Return maximum possible bandwidth
2301  * @tunnel: Tunnel to check
2302  * @max_up: Maximum upstream bandwidth in Mb/s
2303  * @max_down: Maximum downstream bandwidth in Mb/s
2304  *
2305  * Returns maximum possible bandwidth this tunnel can go if not limited
2306  * by other bandwidth clients. If the tunnel does not support this
2307  * returns %-EOPNOTSUPP.
2308  */
2309 int tb_tunnel_maximum_bandwidth(struct tb_tunnel *tunnel, int *max_up,
2310                                 int *max_down)
2311 {
2312         if (!tb_tunnel_is_active(tunnel))
2313                 return -EINVAL;
2314
2315         if (tunnel->maximum_bandwidth)
2316                 return tunnel->maximum_bandwidth(tunnel, max_up, max_down);
2317         return -EOPNOTSUPP;
2318 }
2319
2320 /**
2321  * tb_tunnel_allocated_bandwidth() - Return bandwidth allocated for the tunnel
2322  * @tunnel: Tunnel to check
2323  * @allocated_up: Currently allocated upstream bandwidth in Mb/s is stored here
2324  * @allocated_down: Currently allocated downstream bandwidth in Mb/s is
2325  *                  stored here
2326  *
2327  * Returns the bandwidth allocated for the tunnel. This may be higher
2328  * than what the tunnel actually consumes.
2329  */
2330 int tb_tunnel_allocated_bandwidth(struct tb_tunnel *tunnel, int *allocated_up,
2331                                   int *allocated_down)
2332 {
2333         if (!tb_tunnel_is_active(tunnel))
2334                 return -EINVAL;
2335
2336         if (tunnel->allocated_bandwidth)
2337                 return tunnel->allocated_bandwidth(tunnel, allocated_up,
2338                                                    allocated_down);
2339         return -EOPNOTSUPP;
2340 }
2341
2342 /**
2343  * tb_tunnel_alloc_bandwidth() - Change tunnel bandwidth allocation
2344  * @tunnel: Tunnel whose bandwidth allocation to change
2345  * @alloc_up: New upstream bandwidth in Mb/s
2346  * @alloc_down: New downstream bandwidth in Mb/s
2347  *
2348  * Tries to change tunnel bandwidth allocation. If succeeds returns %0
2349  * and updates @alloc_up and @alloc_down to that was actually allocated
2350  * (it may not be the same as passed originally). Returns negative errno
2351  * in case of failure.
2352  */
2353 int tb_tunnel_alloc_bandwidth(struct tb_tunnel *tunnel, int *alloc_up,
2354                               int *alloc_down)
2355 {
2356         if (!tb_tunnel_is_active(tunnel))
2357                 return -EINVAL;
2358
2359         if (tunnel->alloc_bandwidth)
2360                 return tunnel->alloc_bandwidth(tunnel, alloc_up, alloc_down);
2361
2362         return -EOPNOTSUPP;
2363 }
2364
2365 /**
2366  * tb_tunnel_consumed_bandwidth() - Return bandwidth consumed by the tunnel
2367  * @tunnel: Tunnel to check
2368  * @consumed_up: Consumed bandwidth in Mb/s from @dst_port to @src_port.
2369  *               Can be %NULL.
2370  * @consumed_down: Consumed bandwidth in Mb/s from @src_port to @dst_port.
2371  *                 Can be %NULL.
2372  *
2373  * Stores the amount of isochronous bandwidth @tunnel consumes in
2374  * @consumed_up and @consumed_down. In case of success returns %0,
2375  * negative errno otherwise.
2376  */
2377 int tb_tunnel_consumed_bandwidth(struct tb_tunnel *tunnel, int *consumed_up,
2378                                  int *consumed_down)
2379 {
2380         int up_bw = 0, down_bw = 0;
2381
2382         if (!tb_tunnel_is_active(tunnel))
2383                 goto out;
2384
2385         if (tunnel->consumed_bandwidth) {
2386                 int ret;
2387
2388                 ret = tunnel->consumed_bandwidth(tunnel, &up_bw, &down_bw);
2389                 if (ret)
2390                         return ret;
2391
2392                 tb_tunnel_dbg(tunnel, "consumed bandwidth %d/%d Mb/s\n", up_bw,
2393                               down_bw);
2394         }
2395
2396 out:
2397         if (consumed_up)
2398                 *consumed_up = up_bw;
2399         if (consumed_down)
2400                 *consumed_down = down_bw;
2401
2402         return 0;
2403 }
2404
2405 /**
2406  * tb_tunnel_release_unused_bandwidth() - Release unused bandwidth
2407  * @tunnel: Tunnel whose unused bandwidth to release
2408  *
2409  * If tunnel supports dynamic bandwidth management (USB3 tunnels at the
2410  * moment) this function makes it to release all the unused bandwidth.
2411  *
2412  * Returns %0 in case of success and negative errno otherwise.
2413  */
2414 int tb_tunnel_release_unused_bandwidth(struct tb_tunnel *tunnel)
2415 {
2416         if (!tb_tunnel_is_active(tunnel))
2417                 return 0;
2418
2419         if (tunnel->release_unused_bandwidth) {
2420                 int ret;
2421
2422                 ret = tunnel->release_unused_bandwidth(tunnel);
2423                 if (ret)
2424                         return ret;
2425         }
2426
2427         return 0;
2428 }
2429
2430 /**
2431  * tb_tunnel_reclaim_available_bandwidth() - Reclaim available bandwidth
2432  * @tunnel: Tunnel reclaiming available bandwidth
2433  * @available_up: Available upstream bandwidth (in Mb/s)
2434  * @available_down: Available downstream bandwidth (in Mb/s)
2435  *
2436  * Reclaims bandwidth from @available_up and @available_down and updates
2437  * the variables accordingly (e.g decreases both according to what was
2438  * reclaimed by the tunnel). If nothing was reclaimed the values are
2439  * kept as is.
2440  */
2441 void tb_tunnel_reclaim_available_bandwidth(struct tb_tunnel *tunnel,
2442                                            int *available_up,
2443                                            int *available_down)
2444 {
2445         if (!tb_tunnel_is_active(tunnel))
2446                 return;
2447
2448         if (tunnel->reclaim_available_bandwidth)
2449                 tunnel->reclaim_available_bandwidth(tunnel, available_up,
2450                                                     available_down);
2451 }
2452
2453 const char *tb_tunnel_type_name(const struct tb_tunnel *tunnel)
2454 {
2455         return tb_tunnel_names[tunnel->type];
2456 }