1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Thunderbolt link controller support 4 * 5 * Copyright (C) 2019, Intel Corporation 6 * Author: Mika Westerberg <mika.westerberg@linux.intel.com> 7 */ 8 9 #include <linux/delay.h> 10 11 #include "tb.h" 12 13 /** 14 * tb_lc_read_uuid() - Read switch UUID from link controller common register 15 * @sw: Switch whose UUID is read 16 * @uuid: UUID is placed here 17 */ tb_lc_read_uuid(struct tb_switch * sw,u32 * uuid)18 int tb_lc_read_uuid(struct tb_switch *sw, u32 *uuid) 19 { 20 if (!sw->cap_lc) 21 return -EINVAL; 22 return tb_sw_read(sw, uuid, TB_CFG_SWITCH, sw->cap_lc + TB_LC_FUSE, 4); 23 } 24 read_lc_desc(struct tb_switch * sw,u32 * desc)25 static int read_lc_desc(struct tb_switch *sw, u32 *desc) 26 { 27 if (!sw->cap_lc) 28 return -EINVAL; 29 return tb_sw_read(sw, desc, TB_CFG_SWITCH, sw->cap_lc + TB_LC_DESC, 1); 30 } 31 find_port_lc_cap(struct tb_port * port)32 static int find_port_lc_cap(struct tb_port *port) 33 { 34 struct tb_switch *sw = port->sw; 35 int start, phys, ret, size; 36 u32 desc; 37 38 ret = read_lc_desc(sw, &desc); 39 if (ret) 40 return ret; 41 42 /* Start of port LC registers */ 43 start = (desc & TB_LC_DESC_SIZE_MASK) >> TB_LC_DESC_SIZE_SHIFT; 44 size = (desc & TB_LC_DESC_PORT_SIZE_MASK) >> TB_LC_DESC_PORT_SIZE_SHIFT; 45 phys = tb_phy_port_from_link(port->port); 46 47 return sw->cap_lc + start + phys * size; 48 } 49 50 /** 51 * tb_lc_reset_port() - Trigger downstream port reset through LC 52 * @port: Port that is reset 53 * 54 * Triggers downstream port reset through link controller registers. 55 * Returns %0 in case of success negative errno otherwise. Only supports 56 * non-USB4 routers with link controller (that's Thunderbolt 2 and 57 * Thunderbolt 3). 58 */ tb_lc_reset_port(struct tb_port * port)59 int tb_lc_reset_port(struct tb_port *port) 60 { 61 struct tb_switch *sw = port->sw; 62 int cap, ret; 63 u32 mode; 64 65 if (sw->generation < 2) 66 return -EINVAL; 67 68 cap = find_port_lc_cap(port); 69 if (cap < 0) 70 return cap; 71 72 ret = tb_sw_read(sw, &mode, TB_CFG_SWITCH, cap + TB_LC_PORT_MODE, 1); 73 if (ret) 74 return ret; 75 76 mode |= TB_LC_PORT_MODE_DPR; 77 78 ret = tb_sw_write(sw, &mode, TB_CFG_SWITCH, cap + TB_LC_PORT_MODE, 1); 79 if (ret) 80 return ret; 81 82 fsleep(10000); 83 84 ret = tb_sw_read(sw, &mode, TB_CFG_SWITCH, cap + TB_LC_PORT_MODE, 1); 85 if (ret) 86 return ret; 87 88 mode &= ~TB_LC_PORT_MODE_DPR; 89 90 return tb_sw_write(sw, &mode, TB_CFG_SWITCH, cap + TB_LC_PORT_MODE, 1); 91 } 92 tb_lc_set_port_configured(struct tb_port * port,bool configured)93 static int tb_lc_set_port_configured(struct tb_port *port, bool configured) 94 { 95 bool upstream = tb_is_upstream_port(port); 96 struct tb_switch *sw = port->sw; 97 u32 ctrl, lane; 98 int cap, ret; 99 100 if (sw->generation < 2) 101 return 0; 102 103 cap = find_port_lc_cap(port); 104 if (cap < 0) 105 return cap; 106 107 ret = tb_sw_read(sw, &ctrl, TB_CFG_SWITCH, cap + TB_LC_SX_CTRL, 1); 108 if (ret) 109 return ret; 110 111 /* Resolve correct lane */ 112 if (port->port % 2) 113 lane = TB_LC_SX_CTRL_L1C; 114 else 115 lane = TB_LC_SX_CTRL_L2C; 116 117 if (configured) { 118 ctrl |= lane; 119 if (upstream) 120 ctrl |= TB_LC_SX_CTRL_UPSTREAM; 121 } else { 122 ctrl &= ~lane; 123 if (upstream) 124 ctrl &= ~TB_LC_SX_CTRL_UPSTREAM; 125 } 126 127 return tb_sw_write(sw, &ctrl, TB_CFG_SWITCH, cap + TB_LC_SX_CTRL, 1); 128 } 129 130 /** 131 * tb_lc_configure_port() - Let LC know about configured port 132 * @port: Port that is set as configured 133 * 134 * Sets the port configured for power management purposes. 135 */ tb_lc_configure_port(struct tb_port * port)136 int tb_lc_configure_port(struct tb_port *port) 137 { 138 return tb_lc_set_port_configured(port, true); 139 } 140 141 /** 142 * tb_lc_unconfigure_port() - Let LC know about unconfigured port 143 * @port: Port that is set as configured 144 * 145 * Sets the port unconfigured for power management purposes. 146 */ tb_lc_unconfigure_port(struct tb_port * port)147 void tb_lc_unconfigure_port(struct tb_port *port) 148 { 149 tb_lc_set_port_configured(port, false); 150 } 151 tb_lc_set_xdomain_configured(struct tb_port * port,bool configure)152 static int tb_lc_set_xdomain_configured(struct tb_port *port, bool configure) 153 { 154 struct tb_switch *sw = port->sw; 155 u32 ctrl, lane; 156 int cap, ret; 157 158 if (sw->generation < 2) 159 return 0; 160 161 cap = find_port_lc_cap(port); 162 if (cap < 0) 163 return cap; 164 165 ret = tb_sw_read(sw, &ctrl, TB_CFG_SWITCH, cap + TB_LC_SX_CTRL, 1); 166 if (ret) 167 return ret; 168 169 /* Resolve correct lane */ 170 if (port->port % 2) 171 lane = TB_LC_SX_CTRL_L1D; 172 else 173 lane = TB_LC_SX_CTRL_L2D; 174 175 if (configure) 176 ctrl |= lane; 177 else 178 ctrl &= ~lane; 179 180 return tb_sw_write(sw, &ctrl, TB_CFG_SWITCH, cap + TB_LC_SX_CTRL, 1); 181 } 182 183 /** 184 * tb_lc_configure_xdomain() - Inform LC that the link is XDomain 185 * @port: Switch downstream port connected to another host 186 * 187 * Sets the lane configured for XDomain accordingly so that the LC knows 188 * about this. Returns %0 in success and negative errno in failure. 189 */ tb_lc_configure_xdomain(struct tb_port * port)190 int tb_lc_configure_xdomain(struct tb_port *port) 191 { 192 return tb_lc_set_xdomain_configured(port, true); 193 } 194 195 /** 196 * tb_lc_unconfigure_xdomain() - Unconfigure XDomain from port 197 * @port: Switch downstream port that was connected to another host 198 * 199 * Unsets the lane XDomain configuration. 200 */ tb_lc_unconfigure_xdomain(struct tb_port * port)201 void tb_lc_unconfigure_xdomain(struct tb_port *port) 202 { 203 tb_lc_set_xdomain_configured(port, false); 204 } 205 206 /** 207 * tb_lc_start_lane_initialization() - Start lane initialization 208 * @port: Device router lane 0 adapter 209 * 210 * Starts lane initialization for @port after the router resumed from 211 * sleep. Should be called for those downstream lane adapters that were 212 * not connected (tb_lc_configure_port() was not called) before sleep. 213 * 214 * Returns %0 in success and negative errno in case of failure. 215 */ tb_lc_start_lane_initialization(struct tb_port * port)216 int tb_lc_start_lane_initialization(struct tb_port *port) 217 { 218 struct tb_switch *sw = port->sw; 219 int ret, cap; 220 u32 ctrl; 221 222 if (!tb_route(sw)) 223 return 0; 224 225 if (sw->generation < 2) 226 return 0; 227 228 cap = find_port_lc_cap(port); 229 if (cap < 0) 230 return cap; 231 232 ret = tb_sw_read(sw, &ctrl, TB_CFG_SWITCH, cap + TB_LC_SX_CTRL, 1); 233 if (ret) 234 return ret; 235 236 ctrl |= TB_LC_SX_CTRL_SLI; 237 238 return tb_sw_write(sw, &ctrl, TB_CFG_SWITCH, cap + TB_LC_SX_CTRL, 1); 239 } 240 241 /** 242 * tb_lc_is_clx_supported() - Check whether CLx is supported by the lane adapter 243 * @port: Lane adapter 244 * 245 * TB_LC_LINK_ATTR_CPS bit reflects if the link supports CLx including 246 * active cables (if connected on the link). 247 */ tb_lc_is_clx_supported(struct tb_port * port)248 bool tb_lc_is_clx_supported(struct tb_port *port) 249 { 250 struct tb_switch *sw = port->sw; 251 int cap, ret; 252 u32 val; 253 254 cap = find_port_lc_cap(port); 255 if (cap < 0) 256 return false; 257 258 ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, cap + TB_LC_LINK_ATTR, 1); 259 if (ret) 260 return false; 261 262 return !!(val & TB_LC_LINK_ATTR_CPS); 263 } 264 265 /** 266 * tb_lc_is_usb_plugged() - Is there USB device connected to port 267 * @port: Device router lane 0 adapter 268 * 269 * Returns true if the @port has USB type-C device connected. 270 */ tb_lc_is_usb_plugged(struct tb_port * port)271 bool tb_lc_is_usb_plugged(struct tb_port *port) 272 { 273 struct tb_switch *sw = port->sw; 274 int cap, ret; 275 u32 val; 276 277 if (sw->generation != 3) 278 return false; 279 280 cap = find_port_lc_cap(port); 281 if (cap < 0) 282 return false; 283 284 ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, cap + TB_LC_CS_42, 1); 285 if (ret) 286 return false; 287 288 return !!(val & TB_LC_CS_42_USB_PLUGGED); 289 } 290 291 /** 292 * tb_lc_is_xhci_connected() - Is the internal xHCI connected 293 * @port: Device router lane 0 adapter 294 * 295 * Returns true if the internal xHCI has been connected to @port. 296 */ tb_lc_is_xhci_connected(struct tb_port * port)297 bool tb_lc_is_xhci_connected(struct tb_port *port) 298 { 299 struct tb_switch *sw = port->sw; 300 int cap, ret; 301 u32 val; 302 303 if (sw->generation != 3) 304 return false; 305 306 cap = find_port_lc_cap(port); 307 if (cap < 0) 308 return false; 309 310 ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, cap + TB_LC_LINK_REQ, 1); 311 if (ret) 312 return false; 313 314 return !!(val & TB_LC_LINK_REQ_XHCI_CONNECT); 315 } 316 __tb_lc_xhci_connect(struct tb_port * port,bool connect)317 static int __tb_lc_xhci_connect(struct tb_port *port, bool connect) 318 { 319 struct tb_switch *sw = port->sw; 320 int cap, ret; 321 u32 val; 322 323 if (sw->generation != 3) 324 return -EINVAL; 325 326 cap = find_port_lc_cap(port); 327 if (cap < 0) 328 return cap; 329 330 ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, cap + TB_LC_LINK_REQ, 1); 331 if (ret) 332 return ret; 333 334 if (connect) 335 val |= TB_LC_LINK_REQ_XHCI_CONNECT; 336 else 337 val &= ~TB_LC_LINK_REQ_XHCI_CONNECT; 338 339 return tb_sw_write(sw, &val, TB_CFG_SWITCH, cap + TB_LC_LINK_REQ, 1); 340 } 341 342 /** 343 * tb_lc_xhci_connect() - Connect internal xHCI 344 * @port: Device router lane 0 adapter 345 * 346 * Tells LC to connect the internal xHCI to @port. Returns %0 on success 347 * and negative errno in case of failure. Can be called for Thunderbolt 3 348 * routers only. 349 */ tb_lc_xhci_connect(struct tb_port * port)350 int tb_lc_xhci_connect(struct tb_port *port) 351 { 352 int ret; 353 354 ret = __tb_lc_xhci_connect(port, true); 355 if (ret) 356 return ret; 357 358 tb_port_dbg(port, "xHCI connected\n"); 359 return 0; 360 } 361 362 /** 363 * tb_lc_xhci_disconnect() - Disconnect internal xHCI 364 * @port: Device router lane 0 adapter 365 * 366 * Tells LC to disconnect the internal xHCI from @port. Can be called 367 * for Thunderbolt 3 routers only. 368 */ tb_lc_xhci_disconnect(struct tb_port * port)369 void tb_lc_xhci_disconnect(struct tb_port *port) 370 { 371 __tb_lc_xhci_connect(port, false); 372 tb_port_dbg(port, "xHCI disconnected\n"); 373 } 374 tb_lc_set_wake_one(struct tb_switch * sw,unsigned int offset,unsigned int flags)375 static int tb_lc_set_wake_one(struct tb_switch *sw, unsigned int offset, 376 unsigned int flags) 377 { 378 u32 ctrl; 379 int ret; 380 381 /* 382 * Enable wake on PCIe and USB4 (wake coming from another 383 * router). 384 */ 385 ret = tb_sw_read(sw, &ctrl, TB_CFG_SWITCH, 386 offset + TB_LC_SX_CTRL, 1); 387 if (ret) 388 return ret; 389 390 ctrl &= ~(TB_LC_SX_CTRL_WOC | TB_LC_SX_CTRL_WOD | TB_LC_SX_CTRL_WODPC | 391 TB_LC_SX_CTRL_WODPD | TB_LC_SX_CTRL_WOP | TB_LC_SX_CTRL_WOU4); 392 393 if (flags & TB_WAKE_ON_CONNECT) 394 ctrl |= TB_LC_SX_CTRL_WOC | TB_LC_SX_CTRL_WOD; 395 if (flags & TB_WAKE_ON_USB4) 396 ctrl |= TB_LC_SX_CTRL_WOU4; 397 if (flags & TB_WAKE_ON_PCIE) 398 ctrl |= TB_LC_SX_CTRL_WOP; 399 if (flags & TB_WAKE_ON_DP) 400 ctrl |= TB_LC_SX_CTRL_WODPC | TB_LC_SX_CTRL_WODPD; 401 402 return tb_sw_write(sw, &ctrl, TB_CFG_SWITCH, offset + TB_LC_SX_CTRL, 1); 403 } 404 405 /** 406 * tb_lc_set_wake() - Enable/disable wake 407 * @sw: Switch whose wakes to configure 408 * @flags: Wakeup flags (%0 to disable) 409 * 410 * For each LC sets wake bits accordingly. 411 */ tb_lc_set_wake(struct tb_switch * sw,unsigned int flags)412 int tb_lc_set_wake(struct tb_switch *sw, unsigned int flags) 413 { 414 int start, size, nlc, ret, i; 415 u32 desc; 416 417 if (sw->generation < 2) 418 return 0; 419 420 if (!tb_route(sw)) 421 return 0; 422 423 ret = read_lc_desc(sw, &desc); 424 if (ret) 425 return ret; 426 427 /* Figure out number of link controllers */ 428 nlc = desc & TB_LC_DESC_NLC_MASK; 429 start = (desc & TB_LC_DESC_SIZE_MASK) >> TB_LC_DESC_SIZE_SHIFT; 430 size = (desc & TB_LC_DESC_PORT_SIZE_MASK) >> TB_LC_DESC_PORT_SIZE_SHIFT; 431 432 /* For each link controller set sleep bit */ 433 for (i = 0; i < nlc; i++) { 434 unsigned int offset = sw->cap_lc + start + i * size; 435 436 ret = tb_lc_set_wake_one(sw, offset, flags); 437 if (ret) 438 return ret; 439 } 440 441 return 0; 442 } 443 444 /** 445 * tb_lc_set_sleep() - Inform LC that the switch is going to sleep 446 * @sw: Switch to set sleep 447 * 448 * Let the switch link controllers know that the switch is going to 449 * sleep. 450 */ tb_lc_set_sleep(struct tb_switch * sw)451 int tb_lc_set_sleep(struct tb_switch *sw) 452 { 453 int start, size, nlc, ret, i; 454 u32 desc; 455 456 if (sw->generation < 2) 457 return 0; 458 459 ret = read_lc_desc(sw, &desc); 460 if (ret) 461 return ret; 462 463 /* Figure out number of link controllers */ 464 nlc = desc & TB_LC_DESC_NLC_MASK; 465 start = (desc & TB_LC_DESC_SIZE_MASK) >> TB_LC_DESC_SIZE_SHIFT; 466 size = (desc & TB_LC_DESC_PORT_SIZE_MASK) >> TB_LC_DESC_PORT_SIZE_SHIFT; 467 468 /* For each link controller set sleep bit */ 469 for (i = 0; i < nlc; i++) { 470 unsigned int offset = sw->cap_lc + start + i * size; 471 u32 ctrl; 472 473 ret = tb_sw_read(sw, &ctrl, TB_CFG_SWITCH, 474 offset + TB_LC_SX_CTRL, 1); 475 if (ret) 476 return ret; 477 478 ctrl |= TB_LC_SX_CTRL_SLP; 479 ret = tb_sw_write(sw, &ctrl, TB_CFG_SWITCH, 480 offset + TB_LC_SX_CTRL, 1); 481 if (ret) 482 return ret; 483 } 484 485 return 0; 486 } 487 488 /** 489 * tb_lc_lane_bonding_possible() - Is lane bonding possible towards switch 490 * @sw: Switch to check 491 * 492 * Checks whether conditions for lane bonding from parent to @sw are 493 * possible. 494 */ tb_lc_lane_bonding_possible(struct tb_switch * sw)495 bool tb_lc_lane_bonding_possible(struct tb_switch *sw) 496 { 497 struct tb_port *up; 498 int cap, ret; 499 u32 val; 500 501 if (sw->generation < 2) 502 return false; 503 504 up = tb_upstream_port(sw); 505 cap = find_port_lc_cap(up); 506 if (cap < 0) 507 return false; 508 509 ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, cap + TB_LC_PORT_ATTR, 1); 510 if (ret) 511 return false; 512 513 return !!(val & TB_LC_PORT_ATTR_BE); 514 } 515 tb_lc_dp_sink_from_port(const struct tb_switch * sw,struct tb_port * in)516 static int tb_lc_dp_sink_from_port(const struct tb_switch *sw, 517 struct tb_port *in) 518 { 519 struct tb_port *port; 520 521 /* The first DP IN port is sink 0 and second is sink 1 */ 522 tb_switch_for_each_port(sw, port) { 523 if (tb_port_is_dpin(port)) 524 return in != port; 525 } 526 527 return -EINVAL; 528 } 529 tb_lc_dp_sink_available(struct tb_switch * sw,int sink)530 static int tb_lc_dp_sink_available(struct tb_switch *sw, int sink) 531 { 532 u32 val, alloc; 533 int ret; 534 535 ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, 536 sw->cap_lc + TB_LC_SNK_ALLOCATION, 1); 537 if (ret) 538 return ret; 539 540 /* 541 * Sink is available for CM/SW to use if the allocation valie is 542 * either 0 or 1. 543 */ 544 if (!sink) { 545 alloc = val & TB_LC_SNK_ALLOCATION_SNK0_MASK; 546 if (!alloc || alloc == TB_LC_SNK_ALLOCATION_SNK0_CM) 547 return 0; 548 } else { 549 alloc = (val & TB_LC_SNK_ALLOCATION_SNK1_MASK) >> 550 TB_LC_SNK_ALLOCATION_SNK1_SHIFT; 551 if (!alloc || alloc == TB_LC_SNK_ALLOCATION_SNK1_CM) 552 return 0; 553 } 554 555 return -EBUSY; 556 } 557 558 /** 559 * tb_lc_dp_sink_query() - Is DP sink available for DP IN port 560 * @sw: Switch whose DP sink is queried 561 * @in: DP IN port to check 562 * 563 * Queries through LC SNK_ALLOCATION registers whether DP sink is available 564 * for the given DP IN port or not. 565 */ tb_lc_dp_sink_query(struct tb_switch * sw,struct tb_port * in)566 bool tb_lc_dp_sink_query(struct tb_switch *sw, struct tb_port *in) 567 { 568 int sink; 569 570 /* 571 * For older generations sink is always available as there is no 572 * allocation mechanism. 573 */ 574 if (sw->generation < 3) 575 return true; 576 577 sink = tb_lc_dp_sink_from_port(sw, in); 578 if (sink < 0) 579 return false; 580 581 return !tb_lc_dp_sink_available(sw, sink); 582 } 583 584 /** 585 * tb_lc_dp_sink_alloc() - Allocate DP sink 586 * @sw: Switch whose DP sink is allocated 587 * @in: DP IN port the DP sink is allocated for 588 * 589 * Allocate DP sink for @in via LC SNK_ALLOCATION registers. If the 590 * resource is available and allocation is successful returns %0. In all 591 * other cases returs negative errno. In particular %-EBUSY is returned if 592 * the resource was not available. 593 */ tb_lc_dp_sink_alloc(struct tb_switch * sw,struct tb_port * in)594 int tb_lc_dp_sink_alloc(struct tb_switch *sw, struct tb_port *in) 595 { 596 int ret, sink; 597 u32 val; 598 599 if (sw->generation < 3) 600 return 0; 601 602 sink = tb_lc_dp_sink_from_port(sw, in); 603 if (sink < 0) 604 return sink; 605 606 ret = tb_lc_dp_sink_available(sw, sink); 607 if (ret) 608 return ret; 609 610 ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, 611 sw->cap_lc + TB_LC_SNK_ALLOCATION, 1); 612 if (ret) 613 return ret; 614 615 if (!sink) { 616 val &= ~TB_LC_SNK_ALLOCATION_SNK0_MASK; 617 val |= TB_LC_SNK_ALLOCATION_SNK0_CM; 618 } else { 619 val &= ~TB_LC_SNK_ALLOCATION_SNK1_MASK; 620 val |= TB_LC_SNK_ALLOCATION_SNK1_CM << 621 TB_LC_SNK_ALLOCATION_SNK1_SHIFT; 622 } 623 624 ret = tb_sw_write(sw, &val, TB_CFG_SWITCH, 625 sw->cap_lc + TB_LC_SNK_ALLOCATION, 1); 626 627 if (ret) 628 return ret; 629 630 tb_port_dbg(in, "sink %d allocated\n", sink); 631 return 0; 632 } 633 634 /** 635 * tb_lc_dp_sink_dealloc() - De-allocate DP sink 636 * @sw: Switch whose DP sink is de-allocated 637 * @in: DP IN port whose DP sink is de-allocated 638 * 639 * De-allocate DP sink from @in using LC SNK_ALLOCATION registers. 640 */ tb_lc_dp_sink_dealloc(struct tb_switch * sw,struct tb_port * in)641 int tb_lc_dp_sink_dealloc(struct tb_switch *sw, struct tb_port *in) 642 { 643 int ret, sink; 644 u32 val; 645 646 if (sw->generation < 3) 647 return 0; 648 649 sink = tb_lc_dp_sink_from_port(sw, in); 650 if (sink < 0) 651 return sink; 652 653 /* Needs to be owned by CM/SW */ 654 ret = tb_lc_dp_sink_available(sw, sink); 655 if (ret) 656 return ret; 657 658 ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, 659 sw->cap_lc + TB_LC_SNK_ALLOCATION, 1); 660 if (ret) 661 return ret; 662 663 if (!sink) 664 val &= ~TB_LC_SNK_ALLOCATION_SNK0_MASK; 665 else 666 val &= ~TB_LC_SNK_ALLOCATION_SNK1_MASK; 667 668 ret = tb_sw_write(sw, &val, TB_CFG_SWITCH, 669 sw->cap_lc + TB_LC_SNK_ALLOCATION, 1); 670 if (ret) 671 return ret; 672 673 tb_port_dbg(in, "sink %d de-allocated\n", sink); 674 return 0; 675 } 676 677 /** 678 * tb_lc_force_power() - Forces LC to be powered on 679 * @sw: Thunderbolt switch 680 * 681 * This is useful to let authentication cycle pass even without 682 * a Thunderbolt link present. 683 */ tb_lc_force_power(struct tb_switch * sw)684 int tb_lc_force_power(struct tb_switch *sw) 685 { 686 u32 in = 0xffff; 687 688 return tb_sw_write(sw, &in, TB_CFG_SWITCH, TB_LC_POWER, 1); 689 } 690