Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Thunderbolt driver - control channel and configuration commands
4 *
5 * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
6 * Copyright (C) 2018, Intel Corporation
7 */
8
9#include <linux/crc32.h>
10#include <linux/delay.h>
11#include <linux/slab.h>
12#include <linux/pci.h>
13#include <linux/dmapool.h>
14#include <linux/workqueue.h>
15
16#include "ctl.h"
17
18
19#define TB_CTL_RX_PKG_COUNT 10
20#define TB_CTL_RETRIES 4
21
22/**
23 * struct tb_ctl - Thunderbolt control channel
24 * @nhi: Pointer to the NHI structure
25 * @tx: Transmit ring
26 * @rx: Receive ring
27 * @frame_pool: DMA pool for control messages
28 * @rx_packets: Received control messages
29 * @request_queue_lock: Lock protecting @request_queue
30 * @request_queue: List of outstanding requests
31 * @running: Is the control channel running at the moment
32 * @timeout_msec: Default timeout for non-raw control messages
33 * @callback: Callback called when hotplug message is received
34 * @callback_data: Data passed to @callback
35 */
36struct tb_ctl {
37 struct tb_nhi *nhi;
38 struct tb_ring *tx;
39 struct tb_ring *rx;
40
41 struct dma_pool *frame_pool;
42 struct ctl_pkg *rx_packets[TB_CTL_RX_PKG_COUNT];
43 struct mutex request_queue_lock;
44 struct list_head request_queue;
45 bool running;
46
47 int timeout_msec;
48 event_cb callback;
49 void *callback_data;
50};
51
52
53#define tb_ctl_WARN(ctl, format, arg...) \
54 dev_WARN(&(ctl)->nhi->pdev->dev, format, ## arg)
55
56#define tb_ctl_err(ctl, format, arg...) \
57 dev_err(&(ctl)->nhi->pdev->dev, format, ## arg)
58
59#define tb_ctl_warn(ctl, format, arg...) \
60 dev_warn(&(ctl)->nhi->pdev->dev, format, ## arg)
61
62#define tb_ctl_info(ctl, format, arg...) \
63 dev_info(&(ctl)->nhi->pdev->dev, format, ## arg)
64
65#define tb_ctl_dbg(ctl, format, arg...) \
66 dev_dbg(&(ctl)->nhi->pdev->dev, format, ## arg)
67
68static DECLARE_WAIT_QUEUE_HEAD(tb_cfg_request_cancel_queue);
69/* Serializes access to request kref_get/put */
70static DEFINE_MUTEX(tb_cfg_request_lock);
71
72/**
73 * tb_cfg_request_alloc() - Allocates a new config request
74 *
75 * This is refcounted object so when you are done with this, call
76 * tb_cfg_request_put() to it.
77 */
78struct tb_cfg_request *tb_cfg_request_alloc(void)
79{
80 struct tb_cfg_request *req;
81
82 req = kzalloc(sizeof(*req), GFP_KERNEL);
83 if (!req)
84 return NULL;
85
86 kref_init(&req->kref);
87
88 return req;
89}
90
91/**
92 * tb_cfg_request_get() - Increase refcount of a request
93 * @req: Request whose refcount is increased
94 */
95void tb_cfg_request_get(struct tb_cfg_request *req)
96{
97 mutex_lock(&tb_cfg_request_lock);
98 kref_get(&req->kref);
99 mutex_unlock(&tb_cfg_request_lock);
100}
101
102static void tb_cfg_request_destroy(struct kref *kref)
103{
104 struct tb_cfg_request *req = container_of(kref, typeof(*req), kref);
105
106 kfree(req);
107}
108
109/**
110 * tb_cfg_request_put() - Decrease refcount and possibly release the request
111 * @req: Request whose refcount is decreased
112 *
113 * Call this function when you are done with the request. When refcount
114 * goes to %0 the object is released.
115 */
116void tb_cfg_request_put(struct tb_cfg_request *req)
117{
118 mutex_lock(&tb_cfg_request_lock);
119 kref_put(&req->kref, tb_cfg_request_destroy);
120 mutex_unlock(&tb_cfg_request_lock);
121}
122
123static int tb_cfg_request_enqueue(struct tb_ctl *ctl,
124 struct tb_cfg_request *req)
125{
126 WARN_ON(test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags));
127 WARN_ON(req->ctl);
128
129 mutex_lock(&ctl->request_queue_lock);
130 if (!ctl->running) {
131 mutex_unlock(&ctl->request_queue_lock);
132 return -ENOTCONN;
133 }
134 req->ctl = ctl;
135 list_add_tail(&req->list, &ctl->request_queue);
136 set_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
137 mutex_unlock(&ctl->request_queue_lock);
138 return 0;
139}
140
141static void tb_cfg_request_dequeue(struct tb_cfg_request *req)
142{
143 struct tb_ctl *ctl = req->ctl;
144
145 mutex_lock(&ctl->request_queue_lock);
146 list_del(&req->list);
147 clear_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
148 if (test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
149 wake_up(&tb_cfg_request_cancel_queue);
150 mutex_unlock(&ctl->request_queue_lock);
151}
152
153static bool tb_cfg_request_is_active(struct tb_cfg_request *req)
154{
155 return test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
156}
157
158static struct tb_cfg_request *
159tb_cfg_request_find(struct tb_ctl *ctl, struct ctl_pkg *pkg)
160{
161 struct tb_cfg_request *req = NULL, *iter;
162
163 mutex_lock(&pkg->ctl->request_queue_lock);
164 list_for_each_entry(iter, &pkg->ctl->request_queue, list) {
165 tb_cfg_request_get(iter);
166 if (iter->match(iter, pkg)) {
167 req = iter;
168 break;
169 }
170 tb_cfg_request_put(iter);
171 }
172 mutex_unlock(&pkg->ctl->request_queue_lock);
173
174 return req;
175}
176
177/* utility functions */
178
179
180static int check_header(const struct ctl_pkg *pkg, u32 len,
181 enum tb_cfg_pkg_type type, u64 route)
182{
183 struct tb_cfg_header *header = pkg->buffer;
184
185 /* check frame, TODO: frame flags */
186 if (WARN(len != pkg->frame.size,
187 "wrong framesize (expected %#x, got %#x)\n",
188 len, pkg->frame.size))
189 return -EIO;
190 if (WARN(type != pkg->frame.eof, "wrong eof (expected %#x, got %#x)\n",
191 type, pkg->frame.eof))
192 return -EIO;
193 if (WARN(pkg->frame.sof, "wrong sof (expected 0x0, got %#x)\n",
194 pkg->frame.sof))
195 return -EIO;
196
197 /* check header */
198 if (WARN(header->unknown != 1 << 9,
199 "header->unknown is %#x\n", header->unknown))
200 return -EIO;
201 if (WARN(route != tb_cfg_get_route(header),
202 "wrong route (expected %llx, got %llx)",
203 route, tb_cfg_get_route(header)))
204 return -EIO;
205 return 0;
206}
207
208static int check_config_address(struct tb_cfg_address addr,
209 enum tb_cfg_space space, u32 offset,
210 u32 length)
211{
212 if (WARN(addr.zero, "addr.zero is %#x\n", addr.zero))
213 return -EIO;
214 if (WARN(space != addr.space, "wrong space (expected %x, got %x\n)",
215 space, addr.space))
216 return -EIO;
217 if (WARN(offset != addr.offset, "wrong offset (expected %x, got %x\n)",
218 offset, addr.offset))
219 return -EIO;
220 if (WARN(length != addr.length, "wrong space (expected %x, got %x\n)",
221 length, addr.length))
222 return -EIO;
223 /*
224 * We cannot check addr->port as it is set to the upstream port of the
225 * sender.
226 */
227 return 0;
228}
229
230static struct tb_cfg_result decode_error(const struct ctl_pkg *response)
231{
232 struct cfg_error_pkg *pkg = response->buffer;
233 struct tb_cfg_result res = { 0 };
234 res.response_route = tb_cfg_get_route(&pkg->header);
235 res.response_port = 0;
236 res.err = check_header(response, sizeof(*pkg), TB_CFG_PKG_ERROR,
237 tb_cfg_get_route(&pkg->header));
238 if (res.err)
239 return res;
240
241 res.err = 1;
242 res.tb_error = pkg->error;
243 res.response_port = pkg->port;
244 return res;
245
246}
247
248static struct tb_cfg_result parse_header(const struct ctl_pkg *pkg, u32 len,
249 enum tb_cfg_pkg_type type, u64 route)
250{
251 struct tb_cfg_header *header = pkg->buffer;
252 struct tb_cfg_result res = { 0 };
253
254 if (pkg->frame.eof == TB_CFG_PKG_ERROR)
255 return decode_error(pkg);
256
257 res.response_port = 0; /* will be updated later for cfg_read/write */
258 res.response_route = tb_cfg_get_route(header);
259 res.err = check_header(pkg, len, type, route);
260 return res;
261}
262
263static void tb_cfg_print_error(struct tb_ctl *ctl,
264 const struct tb_cfg_result *res)
265{
266 WARN_ON(res->err != 1);
267 switch (res->tb_error) {
268 case TB_CFG_ERROR_PORT_NOT_CONNECTED:
269 /* Port is not connected. This can happen during surprise
270 * removal. Do not warn. */
271 return;
272 case TB_CFG_ERROR_INVALID_CONFIG_SPACE:
273 /*
274 * Invalid cfg_space/offset/length combination in
275 * cfg_read/cfg_write.
276 */
277 tb_ctl_dbg(ctl, "%llx:%x: invalid config space or offset\n",
278 res->response_route, res->response_port);
279 return;
280 case TB_CFG_ERROR_NO_SUCH_PORT:
281 /*
282 * - The route contains a non-existent port.
283 * - The route contains a non-PHY port (e.g. PCIe).
284 * - The port in cfg_read/cfg_write does not exist.
285 */
286 tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Invalid port\n",
287 res->response_route, res->response_port);
288 return;
289 case TB_CFG_ERROR_LOOP:
290 tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Route contains a loop\n",
291 res->response_route, res->response_port);
292 return;
293 case TB_CFG_ERROR_LOCK:
294 tb_ctl_warn(ctl, "%llx:%x: downstream port is locked\n",
295 res->response_route, res->response_port);
296 return;
297 default:
298 /* 5,6,7,9 and 11 are also valid error codes */
299 tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Unknown error\n",
300 res->response_route, res->response_port);
301 return;
302 }
303}
304
305static __be32 tb_crc(const void *data, size_t len)
306{
307 return cpu_to_be32(~__crc32c_le(~0, data, len));
308}
309
310static void tb_ctl_pkg_free(struct ctl_pkg *pkg)
311{
312 if (pkg) {
313 dma_pool_free(pkg->ctl->frame_pool,
314 pkg->buffer, pkg->frame.buffer_phy);
315 kfree(pkg);
316 }
317}
318
319static struct ctl_pkg *tb_ctl_pkg_alloc(struct tb_ctl *ctl)
320{
321 struct ctl_pkg *pkg = kzalloc(sizeof(*pkg), GFP_KERNEL);
322 if (!pkg)
323 return NULL;
324 pkg->ctl = ctl;
325 pkg->buffer = dma_pool_alloc(ctl->frame_pool, GFP_KERNEL,
326 &pkg->frame.buffer_phy);
327 if (!pkg->buffer) {
328 kfree(pkg);
329 return NULL;
330 }
331 return pkg;
332}
333
334
335/* RX/TX handling */
336
337static void tb_ctl_tx_callback(struct tb_ring *ring, struct ring_frame *frame,
338 bool canceled)
339{
340 struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
341 tb_ctl_pkg_free(pkg);
342}
343
344/*
345 * tb_cfg_tx() - transmit a packet on the control channel
346 *
347 * len must be a multiple of four.
348 *
349 * Return: Returns 0 on success or an error code on failure.
350 */
351static int tb_ctl_tx(struct tb_ctl *ctl, const void *data, size_t len,
352 enum tb_cfg_pkg_type type)
353{
354 int res;
355 struct ctl_pkg *pkg;
356 if (len % 4 != 0) { /* required for le->be conversion */
357 tb_ctl_WARN(ctl, "TX: invalid size: %zu\n", len);
358 return -EINVAL;
359 }
360 if (len > TB_FRAME_SIZE - 4) { /* checksum is 4 bytes */
361 tb_ctl_WARN(ctl, "TX: packet too large: %zu/%d\n",
362 len, TB_FRAME_SIZE - 4);
363 return -EINVAL;
364 }
365 pkg = tb_ctl_pkg_alloc(ctl);
366 if (!pkg)
367 return -ENOMEM;
368 pkg->frame.callback = tb_ctl_tx_callback;
369 pkg->frame.size = len + 4;
370 pkg->frame.sof = type;
371 pkg->frame.eof = type;
372 cpu_to_be32_array(pkg->buffer, data, len / 4);
373 *(__be32 *) (pkg->buffer + len) = tb_crc(pkg->buffer, len);
374
375 res = tb_ring_tx(ctl->tx, &pkg->frame);
376 if (res) /* ring is stopped */
377 tb_ctl_pkg_free(pkg);
378 return res;
379}
380
381/*
382 * tb_ctl_handle_event() - acknowledge a plug event, invoke ctl->callback
383 */
384static bool tb_ctl_handle_event(struct tb_ctl *ctl, enum tb_cfg_pkg_type type,
385 struct ctl_pkg *pkg, size_t size)
386{
387 return ctl->callback(ctl->callback_data, type, pkg->buffer, size);
388}
389
390static void tb_ctl_rx_submit(struct ctl_pkg *pkg)
391{
392 tb_ring_rx(pkg->ctl->rx, &pkg->frame); /*
393 * We ignore failures during stop.
394 * All rx packets are referenced
395 * from ctl->rx_packets, so we do
396 * not loose them.
397 */
398}
399
400static int tb_async_error(const struct ctl_pkg *pkg)
401{
402 const struct cfg_error_pkg *error = pkg->buffer;
403
404 if (pkg->frame.eof != TB_CFG_PKG_ERROR)
405 return false;
406
407 switch (error->error) {
408 case TB_CFG_ERROR_LINK_ERROR:
409 case TB_CFG_ERROR_HEC_ERROR_DETECTED:
410 case TB_CFG_ERROR_FLOW_CONTROL_ERROR:
411 case TB_CFG_ERROR_DP_BW:
412 case TB_CFG_ERROR_ROP_CMPLT:
413 case TB_CFG_ERROR_POP_CMPLT:
414 case TB_CFG_ERROR_PCIE_WAKE:
415 case TB_CFG_ERROR_DP_CON_CHANGE:
416 case TB_CFG_ERROR_DPTX_DISCOVERY:
417 case TB_CFG_ERROR_LINK_RECOVERY:
418 case TB_CFG_ERROR_ASYM_LINK:
419 return true;
420
421 default:
422 return false;
423 }
424}
425
426static void tb_ctl_rx_callback(struct tb_ring *ring, struct ring_frame *frame,
427 bool canceled)
428{
429 struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
430 struct tb_cfg_request *req;
431 __be32 crc32;
432
433 if (canceled)
434 return; /*
435 * ring is stopped, packet is referenced from
436 * ctl->rx_packets.
437 */
438
439 if (frame->size < 4 || frame->size % 4 != 0) {
440 tb_ctl_err(pkg->ctl, "RX: invalid size %#x, dropping packet\n",
441 frame->size);
442 goto rx;
443 }
444
445 frame->size -= 4; /* remove checksum */
446 crc32 = tb_crc(pkg->buffer, frame->size);
447 be32_to_cpu_array(pkg->buffer, pkg->buffer, frame->size / 4);
448
449 switch (frame->eof) {
450 case TB_CFG_PKG_READ:
451 case TB_CFG_PKG_WRITE:
452 case TB_CFG_PKG_ERROR:
453 case TB_CFG_PKG_OVERRIDE:
454 case TB_CFG_PKG_RESET:
455 if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
456 tb_ctl_err(pkg->ctl,
457 "RX: checksum mismatch, dropping packet\n");
458 goto rx;
459 }
460 if (tb_async_error(pkg)) {
461 tb_ctl_handle_event(pkg->ctl, frame->eof,
462 pkg, frame->size);
463 goto rx;
464 }
465 break;
466
467 case TB_CFG_PKG_EVENT:
468 case TB_CFG_PKG_XDOMAIN_RESP:
469 case TB_CFG_PKG_XDOMAIN_REQ:
470 if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
471 tb_ctl_err(pkg->ctl,
472 "RX: checksum mismatch, dropping packet\n");
473 goto rx;
474 }
475 fallthrough;
476 case TB_CFG_PKG_ICM_EVENT:
477 if (tb_ctl_handle_event(pkg->ctl, frame->eof, pkg, frame->size))
478 goto rx;
479 break;
480
481 default:
482 break;
483 }
484
485 /*
486 * The received packet will be processed only if there is an
487 * active request and that the packet is what is expected. This
488 * prevents packets such as replies coming after timeout has
489 * triggered from messing with the active requests.
490 */
491 req = tb_cfg_request_find(pkg->ctl, pkg);
492 if (req) {
493 if (req->copy(req, pkg))
494 schedule_work(&req->work);
495 tb_cfg_request_put(req);
496 }
497
498rx:
499 tb_ctl_rx_submit(pkg);
500}
501
502static void tb_cfg_request_work(struct work_struct *work)
503{
504 struct tb_cfg_request *req = container_of(work, typeof(*req), work);
505
506 if (!test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
507 req->callback(req->callback_data);
508
509 tb_cfg_request_dequeue(req);
510 tb_cfg_request_put(req);
511}
512
513/**
514 * tb_cfg_request() - Start control request not waiting for it to complete
515 * @ctl: Control channel to use
516 * @req: Request to start
517 * @callback: Callback called when the request is completed
518 * @callback_data: Data to be passed to @callback
519 *
520 * This queues @req on the given control channel without waiting for it
521 * to complete. When the request completes @callback is called.
522 */
523int tb_cfg_request(struct tb_ctl *ctl, struct tb_cfg_request *req,
524 void (*callback)(void *), void *callback_data)
525{
526 int ret;
527
528 req->flags = 0;
529 req->callback = callback;
530 req->callback_data = callback_data;
531 INIT_WORK(&req->work, tb_cfg_request_work);
532 INIT_LIST_HEAD(&req->list);
533
534 tb_cfg_request_get(req);
535 ret = tb_cfg_request_enqueue(ctl, req);
536 if (ret)
537 goto err_put;
538
539 ret = tb_ctl_tx(ctl, req->request, req->request_size,
540 req->request_type);
541 if (ret)
542 goto err_dequeue;
543
544 if (!req->response)
545 schedule_work(&req->work);
546
547 return 0;
548
549err_dequeue:
550 tb_cfg_request_dequeue(req);
551err_put:
552 tb_cfg_request_put(req);
553
554 return ret;
555}
556
557/**
558 * tb_cfg_request_cancel() - Cancel a control request
559 * @req: Request to cancel
560 * @err: Error to assign to the request
561 *
562 * This function can be used to cancel ongoing request. It will wait
563 * until the request is not active anymore.
564 */
565void tb_cfg_request_cancel(struct tb_cfg_request *req, int err)
566{
567 set_bit(TB_CFG_REQUEST_CANCELED, &req->flags);
568 schedule_work(&req->work);
569 wait_event(tb_cfg_request_cancel_queue, !tb_cfg_request_is_active(req));
570 req->result.err = err;
571}
572
573static void tb_cfg_request_complete(void *data)
574{
575 complete(data);
576}
577
578/**
579 * tb_cfg_request_sync() - Start control request and wait until it completes
580 * @ctl: Control channel to use
581 * @req: Request to start
582 * @timeout_msec: Timeout how long to wait @req to complete
583 *
584 * Starts a control request and waits until it completes. If timeout
585 * triggers the request is canceled before function returns. Note the
586 * caller needs to make sure only one message for given switch is active
587 * at a time.
588 */
589struct tb_cfg_result tb_cfg_request_sync(struct tb_ctl *ctl,
590 struct tb_cfg_request *req,
591 int timeout_msec)
592{
593 unsigned long timeout = msecs_to_jiffies(timeout_msec);
594 struct tb_cfg_result res = { 0 };
595 DECLARE_COMPLETION_ONSTACK(done);
596 int ret;
597
598 ret = tb_cfg_request(ctl, req, tb_cfg_request_complete, &done);
599 if (ret) {
600 res.err = ret;
601 return res;
602 }
603
604 if (!wait_for_completion_timeout(&done, timeout))
605 tb_cfg_request_cancel(req, -ETIMEDOUT);
606
607 flush_work(&req->work);
608
609 return req->result;
610}
611
612/* public interface, alloc/start/stop/free */
613
614/**
615 * tb_ctl_alloc() - allocate a control channel
616 * @nhi: Pointer to NHI
617 * @timeout_msec: Default timeout used with non-raw control messages
618 * @cb: Callback called for plug events
619 * @cb_data: Data passed to @cb
620 *
621 * cb will be invoked once for every hot plug event.
622 *
623 * Return: Returns a pointer on success or NULL on failure.
624 */
625struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, int timeout_msec, event_cb cb,
626 void *cb_data)
627{
628 int i;
629 struct tb_ctl *ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
630 if (!ctl)
631 return NULL;
632 ctl->nhi = nhi;
633 ctl->timeout_msec = timeout_msec;
634 ctl->callback = cb;
635 ctl->callback_data = cb_data;
636
637 mutex_init(&ctl->request_queue_lock);
638 INIT_LIST_HEAD(&ctl->request_queue);
639 ctl->frame_pool = dma_pool_create("thunderbolt_ctl", &nhi->pdev->dev,
640 TB_FRAME_SIZE, 4, 0);
641 if (!ctl->frame_pool)
642 goto err;
643
644 ctl->tx = tb_ring_alloc_tx(nhi, 0, 10, RING_FLAG_NO_SUSPEND);
645 if (!ctl->tx)
646 goto err;
647
648 ctl->rx = tb_ring_alloc_rx(nhi, 0, 10, RING_FLAG_NO_SUSPEND, 0, 0xffff,
649 0xffff, NULL, NULL);
650 if (!ctl->rx)
651 goto err;
652
653 for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++) {
654 ctl->rx_packets[i] = tb_ctl_pkg_alloc(ctl);
655 if (!ctl->rx_packets[i])
656 goto err;
657 ctl->rx_packets[i]->frame.callback = tb_ctl_rx_callback;
658 }
659
660 tb_ctl_dbg(ctl, "control channel created\n");
661 return ctl;
662err:
663 tb_ctl_free(ctl);
664 return NULL;
665}
666
667/**
668 * tb_ctl_free() - free a control channel
669 * @ctl: Control channel to free
670 *
671 * Must be called after tb_ctl_stop.
672 *
673 * Must NOT be called from ctl->callback.
674 */
675void tb_ctl_free(struct tb_ctl *ctl)
676{
677 int i;
678
679 if (!ctl)
680 return;
681
682 if (ctl->rx)
683 tb_ring_free(ctl->rx);
684 if (ctl->tx)
685 tb_ring_free(ctl->tx);
686
687 /* free RX packets */
688 for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
689 tb_ctl_pkg_free(ctl->rx_packets[i]);
690
691
692 dma_pool_destroy(ctl->frame_pool);
693 kfree(ctl);
694}
695
696/**
697 * tb_ctl_start() - start/resume the control channel
698 * @ctl: Control channel to start
699 */
700void tb_ctl_start(struct tb_ctl *ctl)
701{
702 int i;
703 tb_ctl_dbg(ctl, "control channel starting...\n");
704 tb_ring_start(ctl->tx); /* is used to ack hotplug packets, start first */
705 tb_ring_start(ctl->rx);
706 for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
707 tb_ctl_rx_submit(ctl->rx_packets[i]);
708
709 ctl->running = true;
710}
711
712/**
713 * tb_ctl_stop() - pause the control channel
714 * @ctl: Control channel to stop
715 *
716 * All invocations of ctl->callback will have finished after this method
717 * returns.
718 *
719 * Must NOT be called from ctl->callback.
720 */
721void tb_ctl_stop(struct tb_ctl *ctl)
722{
723 mutex_lock(&ctl->request_queue_lock);
724 ctl->running = false;
725 mutex_unlock(&ctl->request_queue_lock);
726
727 tb_ring_stop(ctl->rx);
728 tb_ring_stop(ctl->tx);
729
730 if (!list_empty(&ctl->request_queue))
731 tb_ctl_WARN(ctl, "dangling request in request_queue\n");
732 INIT_LIST_HEAD(&ctl->request_queue);
733 tb_ctl_dbg(ctl, "control channel stopped\n");
734}
735
736/* public interface, commands */
737
738/**
739 * tb_cfg_ack_notification() - Ack notification
740 * @ctl: Control channel to use
741 * @route: Router that originated the event
742 * @error: Pointer to the notification package
743 *
744 * Call this as response for non-plug notification to ack it. Returns
745 * %0 on success or an error code on failure.
746 */
747int tb_cfg_ack_notification(struct tb_ctl *ctl, u64 route,
748 const struct cfg_error_pkg *error)
749{
750 struct cfg_ack_pkg pkg = {
751 .header = tb_cfg_make_header(route),
752 };
753 const char *name;
754
755 switch (error->error) {
756 case TB_CFG_ERROR_LINK_ERROR:
757 name = "link error";
758 break;
759 case TB_CFG_ERROR_HEC_ERROR_DETECTED:
760 name = "HEC error";
761 break;
762 case TB_CFG_ERROR_FLOW_CONTROL_ERROR:
763 name = "flow control error";
764 break;
765 case TB_CFG_ERROR_DP_BW:
766 name = "DP_BW";
767 break;
768 case TB_CFG_ERROR_ROP_CMPLT:
769 name = "router operation completion";
770 break;
771 case TB_CFG_ERROR_POP_CMPLT:
772 name = "port operation completion";
773 break;
774 case TB_CFG_ERROR_PCIE_WAKE:
775 name = "PCIe wake";
776 break;
777 case TB_CFG_ERROR_DP_CON_CHANGE:
778 name = "DP connector change";
779 break;
780 case TB_CFG_ERROR_DPTX_DISCOVERY:
781 name = "DPTX discovery";
782 break;
783 case TB_CFG_ERROR_LINK_RECOVERY:
784 name = "link recovery";
785 break;
786 case TB_CFG_ERROR_ASYM_LINK:
787 name = "asymmetric link";
788 break;
789 default:
790 name = "unknown";
791 break;
792 }
793
794 tb_ctl_dbg(ctl, "acking %s (%#x) notification on %llx\n", name,
795 error->error, route);
796
797 return tb_ctl_tx(ctl, &pkg, sizeof(pkg), TB_CFG_PKG_NOTIFY_ACK);
798}
799
800/**
801 * tb_cfg_ack_plug() - Ack hot plug/unplug event
802 * @ctl: Control channel to use
803 * @route: Router that originated the event
804 * @port: Port where the hot plug/unplug happened
805 * @unplug: Ack hot plug or unplug
806 *
807 * Call this as response for hot plug/unplug event to ack it.
808 * Returns %0 on success or an error code on failure.
809 */
810int tb_cfg_ack_plug(struct tb_ctl *ctl, u64 route, u32 port, bool unplug)
811{
812 struct cfg_error_pkg pkg = {
813 .header = tb_cfg_make_header(route),
814 .port = port,
815 .error = TB_CFG_ERROR_ACK_PLUG_EVENT,
816 .pg = unplug ? TB_CFG_ERROR_PG_HOT_UNPLUG
817 : TB_CFG_ERROR_PG_HOT_PLUG,
818 };
819 tb_ctl_dbg(ctl, "acking hot %splug event on %llx:%u\n",
820 unplug ? "un" : "", route, port);
821 return tb_ctl_tx(ctl, &pkg, sizeof(pkg), TB_CFG_PKG_ERROR);
822}
823
824static bool tb_cfg_match(const struct tb_cfg_request *req,
825 const struct ctl_pkg *pkg)
826{
827 u64 route = tb_cfg_get_route(pkg->buffer) & ~BIT_ULL(63);
828
829 if (pkg->frame.eof == TB_CFG_PKG_ERROR)
830 return true;
831
832 if (pkg->frame.eof != req->response_type)
833 return false;
834 if (route != tb_cfg_get_route(req->request))
835 return false;
836 if (pkg->frame.size != req->response_size)
837 return false;
838
839 if (pkg->frame.eof == TB_CFG_PKG_READ ||
840 pkg->frame.eof == TB_CFG_PKG_WRITE) {
841 const struct cfg_read_pkg *req_hdr = req->request;
842 const struct cfg_read_pkg *res_hdr = pkg->buffer;
843
844 if (req_hdr->addr.seq != res_hdr->addr.seq)
845 return false;
846 }
847
848 return true;
849}
850
851static bool tb_cfg_copy(struct tb_cfg_request *req, const struct ctl_pkg *pkg)
852{
853 struct tb_cfg_result res;
854
855 /* Now make sure it is in expected format */
856 res = parse_header(pkg, req->response_size, req->response_type,
857 tb_cfg_get_route(req->request));
858 if (!res.err)
859 memcpy(req->response, pkg->buffer, req->response_size);
860
861 req->result = res;
862
863 /* Always complete when first response is received */
864 return true;
865}
866
867/**
868 * tb_cfg_reset() - send a reset packet and wait for a response
869 * @ctl: Control channel pointer
870 * @route: Router string for the router to send reset
871 *
872 * If the switch at route is incorrectly configured then we will not receive a
873 * reply (even though the switch will reset). The caller should check for
874 * -ETIMEDOUT and attempt to reconfigure the switch.
875 */
876struct tb_cfg_result tb_cfg_reset(struct tb_ctl *ctl, u64 route)
877{
878 struct cfg_reset_pkg request = { .header = tb_cfg_make_header(route) };
879 struct tb_cfg_result res = { 0 };
880 struct tb_cfg_header reply;
881 struct tb_cfg_request *req;
882
883 req = tb_cfg_request_alloc();
884 if (!req) {
885 res.err = -ENOMEM;
886 return res;
887 }
888
889 req->match = tb_cfg_match;
890 req->copy = tb_cfg_copy;
891 req->request = &request;
892 req->request_size = sizeof(request);
893 req->request_type = TB_CFG_PKG_RESET;
894 req->response = &reply;
895 req->response_size = sizeof(reply);
896 req->response_type = TB_CFG_PKG_RESET;
897
898 res = tb_cfg_request_sync(ctl, req, ctl->timeout_msec);
899
900 tb_cfg_request_put(req);
901
902 return res;
903}
904
905/**
906 * tb_cfg_read_raw() - read from config space into buffer
907 * @ctl: Pointer to the control channel
908 * @buffer: Buffer where the data is read
909 * @route: Route string of the router
910 * @port: Port number when reading from %TB_CFG_PORT, %0 otherwise
911 * @space: Config space selector
912 * @offset: Dword word offset of the register to start reading
913 * @length: Number of dwords to read
914 * @timeout_msec: Timeout in ms how long to wait for the response
915 *
916 * Reads from router config space without translating the possible error.
917 */
918struct tb_cfg_result tb_cfg_read_raw(struct tb_ctl *ctl, void *buffer,
919 u64 route, u32 port, enum tb_cfg_space space,
920 u32 offset, u32 length, int timeout_msec)
921{
922 struct tb_cfg_result res = { 0 };
923 struct cfg_read_pkg request = {
924 .header = tb_cfg_make_header(route),
925 .addr = {
926 .port = port,
927 .space = space,
928 .offset = offset,
929 .length = length,
930 },
931 };
932 struct cfg_write_pkg reply;
933 int retries = 0;
934
935 while (retries < TB_CTL_RETRIES) {
936 struct tb_cfg_request *req;
937
938 req = tb_cfg_request_alloc();
939 if (!req) {
940 res.err = -ENOMEM;
941 return res;
942 }
943
944 request.addr.seq = retries++;
945
946 req->match = tb_cfg_match;
947 req->copy = tb_cfg_copy;
948 req->request = &request;
949 req->request_size = sizeof(request);
950 req->request_type = TB_CFG_PKG_READ;
951 req->response = &reply;
952 req->response_size = 12 + 4 * length;
953 req->response_type = TB_CFG_PKG_READ;
954
955 res = tb_cfg_request_sync(ctl, req, timeout_msec);
956
957 tb_cfg_request_put(req);
958
959 if (res.err != -ETIMEDOUT)
960 break;
961
962 /* Wait a bit (arbitrary time) until we send a retry */
963 usleep_range(10, 100);
964 }
965
966 if (res.err)
967 return res;
968
969 res.response_port = reply.addr.port;
970 res.err = check_config_address(reply.addr, space, offset, length);
971 if (!res.err)
972 memcpy(buffer, &reply.data, 4 * length);
973 return res;
974}
975
976/**
977 * tb_cfg_write_raw() - write from buffer into config space
978 * @ctl: Pointer to the control channel
979 * @buffer: Data to write
980 * @route: Route string of the router
981 * @port: Port number when writing to %TB_CFG_PORT, %0 otherwise
982 * @space: Config space selector
983 * @offset: Dword word offset of the register to start writing
984 * @length: Number of dwords to write
985 * @timeout_msec: Timeout in ms how long to wait for the response
986 *
987 * Writes to router config space without translating the possible error.
988 */
989struct tb_cfg_result tb_cfg_write_raw(struct tb_ctl *ctl, const void *buffer,
990 u64 route, u32 port, enum tb_cfg_space space,
991 u32 offset, u32 length, int timeout_msec)
992{
993 struct tb_cfg_result res = { 0 };
994 struct cfg_write_pkg request = {
995 .header = tb_cfg_make_header(route),
996 .addr = {
997 .port = port,
998 .space = space,
999 .offset = offset,
1000 .length = length,
1001 },
1002 };
1003 struct cfg_read_pkg reply;
1004 int retries = 0;
1005
1006 memcpy(&request.data, buffer, length * 4);
1007
1008 while (retries < TB_CTL_RETRIES) {
1009 struct tb_cfg_request *req;
1010
1011 req = tb_cfg_request_alloc();
1012 if (!req) {
1013 res.err = -ENOMEM;
1014 return res;
1015 }
1016
1017 request.addr.seq = retries++;
1018
1019 req->match = tb_cfg_match;
1020 req->copy = tb_cfg_copy;
1021 req->request = &request;
1022 req->request_size = 12 + 4 * length;
1023 req->request_type = TB_CFG_PKG_WRITE;
1024 req->response = &reply;
1025 req->response_size = sizeof(reply);
1026 req->response_type = TB_CFG_PKG_WRITE;
1027
1028 res = tb_cfg_request_sync(ctl, req, timeout_msec);
1029
1030 tb_cfg_request_put(req);
1031
1032 if (res.err != -ETIMEDOUT)
1033 break;
1034
1035 /* Wait a bit (arbitrary time) until we send a retry */
1036 usleep_range(10, 100);
1037 }
1038
1039 if (res.err)
1040 return res;
1041
1042 res.response_port = reply.addr.port;
1043 res.err = check_config_address(reply.addr, space, offset, length);
1044 return res;
1045}
1046
1047static int tb_cfg_get_error(struct tb_ctl *ctl, enum tb_cfg_space space,
1048 const struct tb_cfg_result *res)
1049{
1050 /*
1051 * For unimplemented ports access to port config space may return
1052 * TB_CFG_ERROR_INVALID_CONFIG_SPACE (alternatively their type is
1053 * set to TB_TYPE_INACTIVE). In the former case return -ENODEV so
1054 * that the caller can mark the port as disabled.
1055 */
1056 if (space == TB_CFG_PORT &&
1057 res->tb_error == TB_CFG_ERROR_INVALID_CONFIG_SPACE)
1058 return -ENODEV;
1059
1060 tb_cfg_print_error(ctl, res);
1061
1062 if (res->tb_error == TB_CFG_ERROR_LOCK)
1063 return -EACCES;
1064 if (res->tb_error == TB_CFG_ERROR_PORT_NOT_CONNECTED)
1065 return -ENOTCONN;
1066
1067 return -EIO;
1068}
1069
1070int tb_cfg_read(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
1071 enum tb_cfg_space space, u32 offset, u32 length)
1072{
1073 struct tb_cfg_result res = tb_cfg_read_raw(ctl, buffer, route, port,
1074 space, offset, length, ctl->timeout_msec);
1075 switch (res.err) {
1076 case 0:
1077 /* Success */
1078 break;
1079
1080 case 1:
1081 /* Thunderbolt error, tb_error holds the actual number */
1082 return tb_cfg_get_error(ctl, space, &res);
1083
1084 case -ETIMEDOUT:
1085 tb_ctl_warn(ctl, "%llx: timeout reading config space %u from %#x\n",
1086 route, space, offset);
1087 break;
1088
1089 default:
1090 WARN(1, "tb_cfg_read: %d\n", res.err);
1091 break;
1092 }
1093 return res.err;
1094}
1095
1096int tb_cfg_write(struct tb_ctl *ctl, const void *buffer, u64 route, u32 port,
1097 enum tb_cfg_space space, u32 offset, u32 length)
1098{
1099 struct tb_cfg_result res = tb_cfg_write_raw(ctl, buffer, route, port,
1100 space, offset, length, ctl->timeout_msec);
1101 switch (res.err) {
1102 case 0:
1103 /* Success */
1104 break;
1105
1106 case 1:
1107 /* Thunderbolt error, tb_error holds the actual number */
1108 return tb_cfg_get_error(ctl, space, &res);
1109
1110 case -ETIMEDOUT:
1111 tb_ctl_warn(ctl, "%llx: timeout writing config space %u to %#x\n",
1112 route, space, offset);
1113 break;
1114
1115 default:
1116 WARN(1, "tb_cfg_write: %d\n", res.err);
1117 break;
1118 }
1119 return res.err;
1120}
1121
1122/**
1123 * tb_cfg_get_upstream_port() - get upstream port number of switch at route
1124 * @ctl: Pointer to the control channel
1125 * @route: Route string of the router
1126 *
1127 * Reads the first dword from the switches TB_CFG_SWITCH config area and
1128 * returns the port number from which the reply originated.
1129 *
1130 * Return: Returns the upstream port number on success or an error code on
1131 * failure.
1132 */
1133int tb_cfg_get_upstream_port(struct tb_ctl *ctl, u64 route)
1134{
1135 u32 dummy;
1136 struct tb_cfg_result res = tb_cfg_read_raw(ctl, &dummy, route, 0,
1137 TB_CFG_SWITCH, 0, 1,
1138 ctl->timeout_msec);
1139 if (res.err == 1)
1140 return -EIO;
1141 if (res.err)
1142 return res.err;
1143 return res.response_port;
1144}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Thunderbolt driver - control channel and configuration commands
4 *
5 * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
6 * Copyright (C) 2018, Intel Corporation
7 */
8
9#include <linux/crc32.h>
10#include <linux/delay.h>
11#include <linux/slab.h>
12#include <linux/pci.h>
13#include <linux/dmapool.h>
14#include <linux/workqueue.h>
15
16#include "ctl.h"
17
18
19#define TB_CTL_RX_PKG_COUNT 10
20#define TB_CTL_RETRIES 4
21
22/**
23 * struct tb_cfg - thunderbolt control channel
24 */
25struct tb_ctl {
26 struct tb_nhi *nhi;
27 struct tb_ring *tx;
28 struct tb_ring *rx;
29
30 struct dma_pool *frame_pool;
31 struct ctl_pkg *rx_packets[TB_CTL_RX_PKG_COUNT];
32 struct mutex request_queue_lock;
33 struct list_head request_queue;
34 bool running;
35
36 event_cb callback;
37 void *callback_data;
38};
39
40
41#define tb_ctl_WARN(ctl, format, arg...) \
42 dev_WARN(&(ctl)->nhi->pdev->dev, format, ## arg)
43
44#define tb_ctl_err(ctl, format, arg...) \
45 dev_err(&(ctl)->nhi->pdev->dev, format, ## arg)
46
47#define tb_ctl_warn(ctl, format, arg...) \
48 dev_warn(&(ctl)->nhi->pdev->dev, format, ## arg)
49
50#define tb_ctl_info(ctl, format, arg...) \
51 dev_info(&(ctl)->nhi->pdev->dev, format, ## arg)
52
53#define tb_ctl_dbg(ctl, format, arg...) \
54 dev_dbg(&(ctl)->nhi->pdev->dev, format, ## arg)
55
56static DECLARE_WAIT_QUEUE_HEAD(tb_cfg_request_cancel_queue);
57/* Serializes access to request kref_get/put */
58static DEFINE_MUTEX(tb_cfg_request_lock);
59
60/**
61 * tb_cfg_request_alloc() - Allocates a new config request
62 *
63 * This is refcounted object so when you are done with this, call
64 * tb_cfg_request_put() to it.
65 */
66struct tb_cfg_request *tb_cfg_request_alloc(void)
67{
68 struct tb_cfg_request *req;
69
70 req = kzalloc(sizeof(*req), GFP_KERNEL);
71 if (!req)
72 return NULL;
73
74 kref_init(&req->kref);
75
76 return req;
77}
78
79/**
80 * tb_cfg_request_get() - Increase refcount of a request
81 * @req: Request whose refcount is increased
82 */
83void tb_cfg_request_get(struct tb_cfg_request *req)
84{
85 mutex_lock(&tb_cfg_request_lock);
86 kref_get(&req->kref);
87 mutex_unlock(&tb_cfg_request_lock);
88}
89
90static void tb_cfg_request_destroy(struct kref *kref)
91{
92 struct tb_cfg_request *req = container_of(kref, typeof(*req), kref);
93
94 kfree(req);
95}
96
97/**
98 * tb_cfg_request_put() - Decrease refcount and possibly release the request
99 * @req: Request whose refcount is decreased
100 *
101 * Call this function when you are done with the request. When refcount
102 * goes to %0 the object is released.
103 */
104void tb_cfg_request_put(struct tb_cfg_request *req)
105{
106 mutex_lock(&tb_cfg_request_lock);
107 kref_put(&req->kref, tb_cfg_request_destroy);
108 mutex_unlock(&tb_cfg_request_lock);
109}
110
111static int tb_cfg_request_enqueue(struct tb_ctl *ctl,
112 struct tb_cfg_request *req)
113{
114 WARN_ON(test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags));
115 WARN_ON(req->ctl);
116
117 mutex_lock(&ctl->request_queue_lock);
118 if (!ctl->running) {
119 mutex_unlock(&ctl->request_queue_lock);
120 return -ENOTCONN;
121 }
122 req->ctl = ctl;
123 list_add_tail(&req->list, &ctl->request_queue);
124 set_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
125 mutex_unlock(&ctl->request_queue_lock);
126 return 0;
127}
128
129static void tb_cfg_request_dequeue(struct tb_cfg_request *req)
130{
131 struct tb_ctl *ctl = req->ctl;
132
133 mutex_lock(&ctl->request_queue_lock);
134 list_del(&req->list);
135 clear_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
136 if (test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
137 wake_up(&tb_cfg_request_cancel_queue);
138 mutex_unlock(&ctl->request_queue_lock);
139}
140
141static bool tb_cfg_request_is_active(struct tb_cfg_request *req)
142{
143 return test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
144}
145
146static struct tb_cfg_request *
147tb_cfg_request_find(struct tb_ctl *ctl, struct ctl_pkg *pkg)
148{
149 struct tb_cfg_request *req;
150 bool found = false;
151
152 mutex_lock(&pkg->ctl->request_queue_lock);
153 list_for_each_entry(req, &pkg->ctl->request_queue, list) {
154 tb_cfg_request_get(req);
155 if (req->match(req, pkg)) {
156 found = true;
157 break;
158 }
159 tb_cfg_request_put(req);
160 }
161 mutex_unlock(&pkg->ctl->request_queue_lock);
162
163 return found ? req : NULL;
164}
165
166/* utility functions */
167
168
169static int check_header(const struct ctl_pkg *pkg, u32 len,
170 enum tb_cfg_pkg_type type, u64 route)
171{
172 struct tb_cfg_header *header = pkg->buffer;
173
174 /* check frame, TODO: frame flags */
175 if (WARN(len != pkg->frame.size,
176 "wrong framesize (expected %#x, got %#x)\n",
177 len, pkg->frame.size))
178 return -EIO;
179 if (WARN(type != pkg->frame.eof, "wrong eof (expected %#x, got %#x)\n",
180 type, pkg->frame.eof))
181 return -EIO;
182 if (WARN(pkg->frame.sof, "wrong sof (expected 0x0, got %#x)\n",
183 pkg->frame.sof))
184 return -EIO;
185
186 /* check header */
187 if (WARN(header->unknown != 1 << 9,
188 "header->unknown is %#x\n", header->unknown))
189 return -EIO;
190 if (WARN(route != tb_cfg_get_route(header),
191 "wrong route (expected %llx, got %llx)",
192 route, tb_cfg_get_route(header)))
193 return -EIO;
194 return 0;
195}
196
197static int check_config_address(struct tb_cfg_address addr,
198 enum tb_cfg_space space, u32 offset,
199 u32 length)
200{
201 if (WARN(addr.zero, "addr.zero is %#x\n", addr.zero))
202 return -EIO;
203 if (WARN(space != addr.space, "wrong space (expected %x, got %x\n)",
204 space, addr.space))
205 return -EIO;
206 if (WARN(offset != addr.offset, "wrong offset (expected %x, got %x\n)",
207 offset, addr.offset))
208 return -EIO;
209 if (WARN(length != addr.length, "wrong space (expected %x, got %x\n)",
210 length, addr.length))
211 return -EIO;
212 /*
213 * We cannot check addr->port as it is set to the upstream port of the
214 * sender.
215 */
216 return 0;
217}
218
219static struct tb_cfg_result decode_error(const struct ctl_pkg *response)
220{
221 struct cfg_error_pkg *pkg = response->buffer;
222 struct tb_cfg_result res = { 0 };
223 res.response_route = tb_cfg_get_route(&pkg->header);
224 res.response_port = 0;
225 res.err = check_header(response, sizeof(*pkg), TB_CFG_PKG_ERROR,
226 tb_cfg_get_route(&pkg->header));
227 if (res.err)
228 return res;
229
230 WARN(pkg->zero1, "pkg->zero1 is %#x\n", pkg->zero1);
231 WARN(pkg->zero2, "pkg->zero1 is %#x\n", pkg->zero1);
232 WARN(pkg->zero3, "pkg->zero1 is %#x\n", pkg->zero1);
233 res.err = 1;
234 res.tb_error = pkg->error;
235 res.response_port = pkg->port;
236 return res;
237
238}
239
240static struct tb_cfg_result parse_header(const struct ctl_pkg *pkg, u32 len,
241 enum tb_cfg_pkg_type type, u64 route)
242{
243 struct tb_cfg_header *header = pkg->buffer;
244 struct tb_cfg_result res = { 0 };
245
246 if (pkg->frame.eof == TB_CFG_PKG_ERROR)
247 return decode_error(pkg);
248
249 res.response_port = 0; /* will be updated later for cfg_read/write */
250 res.response_route = tb_cfg_get_route(header);
251 res.err = check_header(pkg, len, type, route);
252 return res;
253}
254
255static void tb_cfg_print_error(struct tb_ctl *ctl,
256 const struct tb_cfg_result *res)
257{
258 WARN_ON(res->err != 1);
259 switch (res->tb_error) {
260 case TB_CFG_ERROR_PORT_NOT_CONNECTED:
261 /* Port is not connected. This can happen during surprise
262 * removal. Do not warn. */
263 return;
264 case TB_CFG_ERROR_INVALID_CONFIG_SPACE:
265 /*
266 * Invalid cfg_space/offset/length combination in
267 * cfg_read/cfg_write.
268 */
269 tb_ctl_WARN(ctl,
270 "CFG_ERROR(%llx:%x): Invalid config space or offset\n",
271 res->response_route, res->response_port);
272 return;
273 case TB_CFG_ERROR_NO_SUCH_PORT:
274 /*
275 * - The route contains a non-existent port.
276 * - The route contains a non-PHY port (e.g. PCIe).
277 * - The port in cfg_read/cfg_write does not exist.
278 */
279 tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Invalid port\n",
280 res->response_route, res->response_port);
281 return;
282 case TB_CFG_ERROR_LOOP:
283 tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Route contains a loop\n",
284 res->response_route, res->response_port);
285 return;
286 default:
287 /* 5,6,7,9 and 11 are also valid error codes */
288 tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Unknown error\n",
289 res->response_route, res->response_port);
290 return;
291 }
292}
293
294static __be32 tb_crc(const void *data, size_t len)
295{
296 return cpu_to_be32(~__crc32c_le(~0, data, len));
297}
298
299static void tb_ctl_pkg_free(struct ctl_pkg *pkg)
300{
301 if (pkg) {
302 dma_pool_free(pkg->ctl->frame_pool,
303 pkg->buffer, pkg->frame.buffer_phy);
304 kfree(pkg);
305 }
306}
307
308static struct ctl_pkg *tb_ctl_pkg_alloc(struct tb_ctl *ctl)
309{
310 struct ctl_pkg *pkg = kzalloc(sizeof(*pkg), GFP_KERNEL);
311 if (!pkg)
312 return NULL;
313 pkg->ctl = ctl;
314 pkg->buffer = dma_pool_alloc(ctl->frame_pool, GFP_KERNEL,
315 &pkg->frame.buffer_phy);
316 if (!pkg->buffer) {
317 kfree(pkg);
318 return NULL;
319 }
320 return pkg;
321}
322
323
324/* RX/TX handling */
325
326static void tb_ctl_tx_callback(struct tb_ring *ring, struct ring_frame *frame,
327 bool canceled)
328{
329 struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
330 tb_ctl_pkg_free(pkg);
331}
332
333/**
334 * tb_cfg_tx() - transmit a packet on the control channel
335 *
336 * len must be a multiple of four.
337 *
338 * Return: Returns 0 on success or an error code on failure.
339 */
340static int tb_ctl_tx(struct tb_ctl *ctl, const void *data, size_t len,
341 enum tb_cfg_pkg_type type)
342{
343 int res;
344 struct ctl_pkg *pkg;
345 if (len % 4 != 0) { /* required for le->be conversion */
346 tb_ctl_WARN(ctl, "TX: invalid size: %zu\n", len);
347 return -EINVAL;
348 }
349 if (len > TB_FRAME_SIZE - 4) { /* checksum is 4 bytes */
350 tb_ctl_WARN(ctl, "TX: packet too large: %zu/%d\n",
351 len, TB_FRAME_SIZE - 4);
352 return -EINVAL;
353 }
354 pkg = tb_ctl_pkg_alloc(ctl);
355 if (!pkg)
356 return -ENOMEM;
357 pkg->frame.callback = tb_ctl_tx_callback;
358 pkg->frame.size = len + 4;
359 pkg->frame.sof = type;
360 pkg->frame.eof = type;
361 cpu_to_be32_array(pkg->buffer, data, len / 4);
362 *(__be32 *) (pkg->buffer + len) = tb_crc(pkg->buffer, len);
363
364 res = tb_ring_tx(ctl->tx, &pkg->frame);
365 if (res) /* ring is stopped */
366 tb_ctl_pkg_free(pkg);
367 return res;
368}
369
370/**
371 * tb_ctl_handle_event() - acknowledge a plug event, invoke ctl->callback
372 */
373static bool tb_ctl_handle_event(struct tb_ctl *ctl, enum tb_cfg_pkg_type type,
374 struct ctl_pkg *pkg, size_t size)
375{
376 return ctl->callback(ctl->callback_data, type, pkg->buffer, size);
377}
378
379static void tb_ctl_rx_submit(struct ctl_pkg *pkg)
380{
381 tb_ring_rx(pkg->ctl->rx, &pkg->frame); /*
382 * We ignore failures during stop.
383 * All rx packets are referenced
384 * from ctl->rx_packets, so we do
385 * not loose them.
386 */
387}
388
389static int tb_async_error(const struct ctl_pkg *pkg)
390{
391 const struct cfg_error_pkg *error = (const struct cfg_error_pkg *)pkg;
392
393 if (pkg->frame.eof != TB_CFG_PKG_ERROR)
394 return false;
395
396 switch (error->error) {
397 case TB_CFG_ERROR_LINK_ERROR:
398 case TB_CFG_ERROR_HEC_ERROR_DETECTED:
399 case TB_CFG_ERROR_FLOW_CONTROL_ERROR:
400 return true;
401
402 default:
403 return false;
404 }
405}
406
407static void tb_ctl_rx_callback(struct tb_ring *ring, struct ring_frame *frame,
408 bool canceled)
409{
410 struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
411 struct tb_cfg_request *req;
412 __be32 crc32;
413
414 if (canceled)
415 return; /*
416 * ring is stopped, packet is referenced from
417 * ctl->rx_packets.
418 */
419
420 if (frame->size < 4 || frame->size % 4 != 0) {
421 tb_ctl_err(pkg->ctl, "RX: invalid size %#x, dropping packet\n",
422 frame->size);
423 goto rx;
424 }
425
426 frame->size -= 4; /* remove checksum */
427 crc32 = tb_crc(pkg->buffer, frame->size);
428 be32_to_cpu_array(pkg->buffer, pkg->buffer, frame->size / 4);
429
430 switch (frame->eof) {
431 case TB_CFG_PKG_READ:
432 case TB_CFG_PKG_WRITE:
433 case TB_CFG_PKG_ERROR:
434 case TB_CFG_PKG_OVERRIDE:
435 case TB_CFG_PKG_RESET:
436 if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
437 tb_ctl_err(pkg->ctl,
438 "RX: checksum mismatch, dropping packet\n");
439 goto rx;
440 }
441 if (tb_async_error(pkg)) {
442 tb_ctl_handle_event(pkg->ctl, frame->eof,
443 pkg, frame->size);
444 goto rx;
445 }
446 break;
447
448 case TB_CFG_PKG_EVENT:
449 case TB_CFG_PKG_XDOMAIN_RESP:
450 case TB_CFG_PKG_XDOMAIN_REQ:
451 if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
452 tb_ctl_err(pkg->ctl,
453 "RX: checksum mismatch, dropping packet\n");
454 goto rx;
455 }
456 fallthrough;
457 case TB_CFG_PKG_ICM_EVENT:
458 if (tb_ctl_handle_event(pkg->ctl, frame->eof, pkg, frame->size))
459 goto rx;
460 break;
461
462 default:
463 break;
464 }
465
466 /*
467 * The received packet will be processed only if there is an
468 * active request and that the packet is what is expected. This
469 * prevents packets such as replies coming after timeout has
470 * triggered from messing with the active requests.
471 */
472 req = tb_cfg_request_find(pkg->ctl, pkg);
473 if (req) {
474 if (req->copy(req, pkg))
475 schedule_work(&req->work);
476 tb_cfg_request_put(req);
477 }
478
479rx:
480 tb_ctl_rx_submit(pkg);
481}
482
483static void tb_cfg_request_work(struct work_struct *work)
484{
485 struct tb_cfg_request *req = container_of(work, typeof(*req), work);
486
487 if (!test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
488 req->callback(req->callback_data);
489
490 tb_cfg_request_dequeue(req);
491 tb_cfg_request_put(req);
492}
493
494/**
495 * tb_cfg_request() - Start control request not waiting for it to complete
496 * @ctl: Control channel to use
497 * @req: Request to start
498 * @callback: Callback called when the request is completed
499 * @callback_data: Data to be passed to @callback
500 *
501 * This queues @req on the given control channel without waiting for it
502 * to complete. When the request completes @callback is called.
503 */
504int tb_cfg_request(struct tb_ctl *ctl, struct tb_cfg_request *req,
505 void (*callback)(void *), void *callback_data)
506{
507 int ret;
508
509 req->flags = 0;
510 req->callback = callback;
511 req->callback_data = callback_data;
512 INIT_WORK(&req->work, tb_cfg_request_work);
513 INIT_LIST_HEAD(&req->list);
514
515 tb_cfg_request_get(req);
516 ret = tb_cfg_request_enqueue(ctl, req);
517 if (ret)
518 goto err_put;
519
520 ret = tb_ctl_tx(ctl, req->request, req->request_size,
521 req->request_type);
522 if (ret)
523 goto err_dequeue;
524
525 if (!req->response)
526 schedule_work(&req->work);
527
528 return 0;
529
530err_dequeue:
531 tb_cfg_request_dequeue(req);
532err_put:
533 tb_cfg_request_put(req);
534
535 return ret;
536}
537
538/**
539 * tb_cfg_request_cancel() - Cancel a control request
540 * @req: Request to cancel
541 * @err: Error to assign to the request
542 *
543 * This function can be used to cancel ongoing request. It will wait
544 * until the request is not active anymore.
545 */
546void tb_cfg_request_cancel(struct tb_cfg_request *req, int err)
547{
548 set_bit(TB_CFG_REQUEST_CANCELED, &req->flags);
549 schedule_work(&req->work);
550 wait_event(tb_cfg_request_cancel_queue, !tb_cfg_request_is_active(req));
551 req->result.err = err;
552}
553
554static void tb_cfg_request_complete(void *data)
555{
556 complete(data);
557}
558
559/**
560 * tb_cfg_request_sync() - Start control request and wait until it completes
561 * @ctl: Control channel to use
562 * @req: Request to start
563 * @timeout_msec: Timeout how long to wait @req to complete
564 *
565 * Starts a control request and waits until it completes. If timeout
566 * triggers the request is canceled before function returns. Note the
567 * caller needs to make sure only one message for given switch is active
568 * at a time.
569 */
570struct tb_cfg_result tb_cfg_request_sync(struct tb_ctl *ctl,
571 struct tb_cfg_request *req,
572 int timeout_msec)
573{
574 unsigned long timeout = msecs_to_jiffies(timeout_msec);
575 struct tb_cfg_result res = { 0 };
576 DECLARE_COMPLETION_ONSTACK(done);
577 int ret;
578
579 ret = tb_cfg_request(ctl, req, tb_cfg_request_complete, &done);
580 if (ret) {
581 res.err = ret;
582 return res;
583 }
584
585 if (!wait_for_completion_timeout(&done, timeout))
586 tb_cfg_request_cancel(req, -ETIMEDOUT);
587
588 flush_work(&req->work);
589
590 return req->result;
591}
592
593/* public interface, alloc/start/stop/free */
594
595/**
596 * tb_ctl_alloc() - allocate a control channel
597 *
598 * cb will be invoked once for every hot plug event.
599 *
600 * Return: Returns a pointer on success or NULL on failure.
601 */
602struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, event_cb cb, void *cb_data)
603{
604 int i;
605 struct tb_ctl *ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
606 if (!ctl)
607 return NULL;
608 ctl->nhi = nhi;
609 ctl->callback = cb;
610 ctl->callback_data = cb_data;
611
612 mutex_init(&ctl->request_queue_lock);
613 INIT_LIST_HEAD(&ctl->request_queue);
614 ctl->frame_pool = dma_pool_create("thunderbolt_ctl", &nhi->pdev->dev,
615 TB_FRAME_SIZE, 4, 0);
616 if (!ctl->frame_pool)
617 goto err;
618
619 ctl->tx = tb_ring_alloc_tx(nhi, 0, 10, RING_FLAG_NO_SUSPEND);
620 if (!ctl->tx)
621 goto err;
622
623 ctl->rx = tb_ring_alloc_rx(nhi, 0, 10, RING_FLAG_NO_SUSPEND, 0xffff,
624 0xffff, NULL, NULL);
625 if (!ctl->rx)
626 goto err;
627
628 for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++) {
629 ctl->rx_packets[i] = tb_ctl_pkg_alloc(ctl);
630 if (!ctl->rx_packets[i])
631 goto err;
632 ctl->rx_packets[i]->frame.callback = tb_ctl_rx_callback;
633 }
634
635 tb_ctl_dbg(ctl, "control channel created\n");
636 return ctl;
637err:
638 tb_ctl_free(ctl);
639 return NULL;
640}
641
642/**
643 * tb_ctl_free() - free a control channel
644 *
645 * Must be called after tb_ctl_stop.
646 *
647 * Must NOT be called from ctl->callback.
648 */
649void tb_ctl_free(struct tb_ctl *ctl)
650{
651 int i;
652
653 if (!ctl)
654 return;
655
656 if (ctl->rx)
657 tb_ring_free(ctl->rx);
658 if (ctl->tx)
659 tb_ring_free(ctl->tx);
660
661 /* free RX packets */
662 for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
663 tb_ctl_pkg_free(ctl->rx_packets[i]);
664
665
666 dma_pool_destroy(ctl->frame_pool);
667 kfree(ctl);
668}
669
670/**
671 * tb_cfg_start() - start/resume the control channel
672 */
673void tb_ctl_start(struct tb_ctl *ctl)
674{
675 int i;
676 tb_ctl_dbg(ctl, "control channel starting...\n");
677 tb_ring_start(ctl->tx); /* is used to ack hotplug packets, start first */
678 tb_ring_start(ctl->rx);
679 for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
680 tb_ctl_rx_submit(ctl->rx_packets[i]);
681
682 ctl->running = true;
683}
684
685/**
686 * control() - pause the control channel
687 *
688 * All invocations of ctl->callback will have finished after this method
689 * returns.
690 *
691 * Must NOT be called from ctl->callback.
692 */
693void tb_ctl_stop(struct tb_ctl *ctl)
694{
695 mutex_lock(&ctl->request_queue_lock);
696 ctl->running = false;
697 mutex_unlock(&ctl->request_queue_lock);
698
699 tb_ring_stop(ctl->rx);
700 tb_ring_stop(ctl->tx);
701
702 if (!list_empty(&ctl->request_queue))
703 tb_ctl_WARN(ctl, "dangling request in request_queue\n");
704 INIT_LIST_HEAD(&ctl->request_queue);
705 tb_ctl_dbg(ctl, "control channel stopped\n");
706}
707
708/* public interface, commands */
709
710/**
711 * tb_cfg_ack_plug() - Ack hot plug/unplug event
712 * @ctl: Control channel to use
713 * @route: Router that originated the event
714 * @port: Port where the hot plug/unplug happened
715 * @unplug: Ack hot plug or unplug
716 *
717 * Call this as response for hot plug/unplug event to ack it.
718 * Returns %0 on success or an error code on failure.
719 */
720int tb_cfg_ack_plug(struct tb_ctl *ctl, u64 route, u32 port, bool unplug)
721{
722 struct cfg_error_pkg pkg = {
723 .header = tb_cfg_make_header(route),
724 .port = port,
725 .error = TB_CFG_ERROR_ACK_PLUG_EVENT,
726 .pg = unplug ? TB_CFG_ERROR_PG_HOT_UNPLUG
727 : TB_CFG_ERROR_PG_HOT_PLUG,
728 };
729 tb_ctl_dbg(ctl, "acking hot %splug event on %llx:%x\n",
730 unplug ? "un" : "", route, port);
731 return tb_ctl_tx(ctl, &pkg, sizeof(pkg), TB_CFG_PKG_ERROR);
732}
733
734static bool tb_cfg_match(const struct tb_cfg_request *req,
735 const struct ctl_pkg *pkg)
736{
737 u64 route = tb_cfg_get_route(pkg->buffer) & ~BIT_ULL(63);
738
739 if (pkg->frame.eof == TB_CFG_PKG_ERROR)
740 return true;
741
742 if (pkg->frame.eof != req->response_type)
743 return false;
744 if (route != tb_cfg_get_route(req->request))
745 return false;
746 if (pkg->frame.size != req->response_size)
747 return false;
748
749 if (pkg->frame.eof == TB_CFG_PKG_READ ||
750 pkg->frame.eof == TB_CFG_PKG_WRITE) {
751 const struct cfg_read_pkg *req_hdr = req->request;
752 const struct cfg_read_pkg *res_hdr = pkg->buffer;
753
754 if (req_hdr->addr.seq != res_hdr->addr.seq)
755 return false;
756 }
757
758 return true;
759}
760
761static bool tb_cfg_copy(struct tb_cfg_request *req, const struct ctl_pkg *pkg)
762{
763 struct tb_cfg_result res;
764
765 /* Now make sure it is in expected format */
766 res = parse_header(pkg, req->response_size, req->response_type,
767 tb_cfg_get_route(req->request));
768 if (!res.err)
769 memcpy(req->response, pkg->buffer, req->response_size);
770
771 req->result = res;
772
773 /* Always complete when first response is received */
774 return true;
775}
776
777/**
778 * tb_cfg_reset() - send a reset packet and wait for a response
779 *
780 * If the switch at route is incorrectly configured then we will not receive a
781 * reply (even though the switch will reset). The caller should check for
782 * -ETIMEDOUT and attempt to reconfigure the switch.
783 */
784struct tb_cfg_result tb_cfg_reset(struct tb_ctl *ctl, u64 route,
785 int timeout_msec)
786{
787 struct cfg_reset_pkg request = { .header = tb_cfg_make_header(route) };
788 struct tb_cfg_result res = { 0 };
789 struct tb_cfg_header reply;
790 struct tb_cfg_request *req;
791
792 req = tb_cfg_request_alloc();
793 if (!req) {
794 res.err = -ENOMEM;
795 return res;
796 }
797
798 req->match = tb_cfg_match;
799 req->copy = tb_cfg_copy;
800 req->request = &request;
801 req->request_size = sizeof(request);
802 req->request_type = TB_CFG_PKG_RESET;
803 req->response = &reply;
804 req->response_size = sizeof(reply);
805 req->response_type = TB_CFG_PKG_RESET;
806
807 res = tb_cfg_request_sync(ctl, req, timeout_msec);
808
809 tb_cfg_request_put(req);
810
811 return res;
812}
813
814/**
815 * tb_cfg_read() - read from config space into buffer
816 *
817 * Offset and length are in dwords.
818 */
819struct tb_cfg_result tb_cfg_read_raw(struct tb_ctl *ctl, void *buffer,
820 u64 route, u32 port, enum tb_cfg_space space,
821 u32 offset, u32 length, int timeout_msec)
822{
823 struct tb_cfg_result res = { 0 };
824 struct cfg_read_pkg request = {
825 .header = tb_cfg_make_header(route),
826 .addr = {
827 .port = port,
828 .space = space,
829 .offset = offset,
830 .length = length,
831 },
832 };
833 struct cfg_write_pkg reply;
834 int retries = 0;
835
836 while (retries < TB_CTL_RETRIES) {
837 struct tb_cfg_request *req;
838
839 req = tb_cfg_request_alloc();
840 if (!req) {
841 res.err = -ENOMEM;
842 return res;
843 }
844
845 request.addr.seq = retries++;
846
847 req->match = tb_cfg_match;
848 req->copy = tb_cfg_copy;
849 req->request = &request;
850 req->request_size = sizeof(request);
851 req->request_type = TB_CFG_PKG_READ;
852 req->response = &reply;
853 req->response_size = 12 + 4 * length;
854 req->response_type = TB_CFG_PKG_READ;
855
856 res = tb_cfg_request_sync(ctl, req, timeout_msec);
857
858 tb_cfg_request_put(req);
859
860 if (res.err != -ETIMEDOUT)
861 break;
862
863 /* Wait a bit (arbitrary time) until we send a retry */
864 usleep_range(10, 100);
865 }
866
867 if (res.err)
868 return res;
869
870 res.response_port = reply.addr.port;
871 res.err = check_config_address(reply.addr, space, offset, length);
872 if (!res.err)
873 memcpy(buffer, &reply.data, 4 * length);
874 return res;
875}
876
877/**
878 * tb_cfg_write() - write from buffer into config space
879 *
880 * Offset and length are in dwords.
881 */
882struct tb_cfg_result tb_cfg_write_raw(struct tb_ctl *ctl, const void *buffer,
883 u64 route, u32 port, enum tb_cfg_space space,
884 u32 offset, u32 length, int timeout_msec)
885{
886 struct tb_cfg_result res = { 0 };
887 struct cfg_write_pkg request = {
888 .header = tb_cfg_make_header(route),
889 .addr = {
890 .port = port,
891 .space = space,
892 .offset = offset,
893 .length = length,
894 },
895 };
896 struct cfg_read_pkg reply;
897 int retries = 0;
898
899 memcpy(&request.data, buffer, length * 4);
900
901 while (retries < TB_CTL_RETRIES) {
902 struct tb_cfg_request *req;
903
904 req = tb_cfg_request_alloc();
905 if (!req) {
906 res.err = -ENOMEM;
907 return res;
908 }
909
910 request.addr.seq = retries++;
911
912 req->match = tb_cfg_match;
913 req->copy = tb_cfg_copy;
914 req->request = &request;
915 req->request_size = 12 + 4 * length;
916 req->request_type = TB_CFG_PKG_WRITE;
917 req->response = &reply;
918 req->response_size = sizeof(reply);
919 req->response_type = TB_CFG_PKG_WRITE;
920
921 res = tb_cfg_request_sync(ctl, req, timeout_msec);
922
923 tb_cfg_request_put(req);
924
925 if (res.err != -ETIMEDOUT)
926 break;
927
928 /* Wait a bit (arbitrary time) until we send a retry */
929 usleep_range(10, 100);
930 }
931
932 if (res.err)
933 return res;
934
935 res.response_port = reply.addr.port;
936 res.err = check_config_address(reply.addr, space, offset, length);
937 return res;
938}
939
940static int tb_cfg_get_error(struct tb_ctl *ctl, enum tb_cfg_space space,
941 const struct tb_cfg_result *res)
942{
943 /*
944 * For unimplemented ports access to port config space may return
945 * TB_CFG_ERROR_INVALID_CONFIG_SPACE (alternatively their type is
946 * set to TB_TYPE_INACTIVE). In the former case return -ENODEV so
947 * that the caller can mark the port as disabled.
948 */
949 if (space == TB_CFG_PORT &&
950 res->tb_error == TB_CFG_ERROR_INVALID_CONFIG_SPACE)
951 return -ENODEV;
952
953 tb_cfg_print_error(ctl, res);
954 return -EIO;
955}
956
957int tb_cfg_read(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
958 enum tb_cfg_space space, u32 offset, u32 length)
959{
960 struct tb_cfg_result res = tb_cfg_read_raw(ctl, buffer, route, port,
961 space, offset, length, TB_CFG_DEFAULT_TIMEOUT);
962 switch (res.err) {
963 case 0:
964 /* Success */
965 break;
966
967 case 1:
968 /* Thunderbolt error, tb_error holds the actual number */
969 return tb_cfg_get_error(ctl, space, &res);
970
971 case -ETIMEDOUT:
972 tb_ctl_warn(ctl, "%llx: timeout reading config space %u from %#x\n",
973 route, space, offset);
974 break;
975
976 default:
977 WARN(1, "tb_cfg_read: %d\n", res.err);
978 break;
979 }
980 return res.err;
981}
982
983int tb_cfg_write(struct tb_ctl *ctl, const void *buffer, u64 route, u32 port,
984 enum tb_cfg_space space, u32 offset, u32 length)
985{
986 struct tb_cfg_result res = tb_cfg_write_raw(ctl, buffer, route, port,
987 space, offset, length, TB_CFG_DEFAULT_TIMEOUT);
988 switch (res.err) {
989 case 0:
990 /* Success */
991 break;
992
993 case 1:
994 /* Thunderbolt error, tb_error holds the actual number */
995 return tb_cfg_get_error(ctl, space, &res);
996
997 case -ETIMEDOUT:
998 tb_ctl_warn(ctl, "%llx: timeout writing config space %u to %#x\n",
999 route, space, offset);
1000 break;
1001
1002 default:
1003 WARN(1, "tb_cfg_write: %d\n", res.err);
1004 break;
1005 }
1006 return res.err;
1007}
1008
1009/**
1010 * tb_cfg_get_upstream_port() - get upstream port number of switch at route
1011 *
1012 * Reads the first dword from the switches TB_CFG_SWITCH config area and
1013 * returns the port number from which the reply originated.
1014 *
1015 * Return: Returns the upstream port number on success or an error code on
1016 * failure.
1017 */
1018int tb_cfg_get_upstream_port(struct tb_ctl *ctl, u64 route)
1019{
1020 u32 dummy;
1021 struct tb_cfg_result res = tb_cfg_read_raw(ctl, &dummy, route, 0,
1022 TB_CFG_SWITCH, 0, 1,
1023 TB_CFG_DEFAULT_TIMEOUT);
1024 if (res.err == 1)
1025 return -EIO;
1026 if (res.err)
1027 return res.err;
1028 return res.response_port;
1029}