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