xref: /linux/drivers/thunderbolt/ctl.c (revision cc8b10fa70682218c2a318fc44f71f3175a23cc0)
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 #define CREATE_TRACE_POINTS
19 #include "trace.h"
20 
21 #define TB_CTL_RX_PKG_COUNT	10
22 #define TB_CTL_RETRIES		4
23 
24 /**
25  * struct tb_ctl - Thunderbolt control channel
26  * @nhi: Pointer to the NHI structure
27  * @tx: Transmit ring
28  * @rx: Receive ring
29  * @frame_pool: DMA pool for control messages
30  * @rx_packets: Received control messages
31  * @request_queue_lock: Lock protecting @request_queue
32  * @request_queue: List of outstanding requests
33  * @running: Is the control channel running at the moment
34  * @timeout_msec: Default timeout for non-raw control messages
35  * @callback: Callback called when hotplug message is received
36  * @callback_data: Data passed to @callback
37  * @index: Domain number. This will be output with the trace record.
38  */
39 struct tb_ctl {
40 	struct tb_nhi *nhi;
41 	struct tb_ring *tx;
42 	struct tb_ring *rx;
43 
44 	struct dma_pool *frame_pool;
45 	struct ctl_pkg *rx_packets[TB_CTL_RX_PKG_COUNT];
46 	struct mutex request_queue_lock;
47 	struct list_head request_queue;
48 	bool running;
49 
50 	int timeout_msec;
51 	event_cb callback;
52 	void *callback_data;
53 
54 	int index;
55 };
56 
57 
58 #define tb_ctl_WARN(ctl, format, arg...) \
59 	dev_WARN(&(ctl)->nhi->pdev->dev, format, ## arg)
60 
61 #define tb_ctl_err(ctl, format, arg...) \
62 	dev_err(&(ctl)->nhi->pdev->dev, format, ## arg)
63 
64 #define tb_ctl_warn(ctl, format, arg...) \
65 	dev_warn(&(ctl)->nhi->pdev->dev, format, ## arg)
66 
67 #define tb_ctl_info(ctl, format, arg...) \
68 	dev_info(&(ctl)->nhi->pdev->dev, format, ## arg)
69 
70 #define tb_ctl_dbg(ctl, format, arg...) \
71 	dev_dbg(&(ctl)->nhi->pdev->dev, format, ## arg)
72 
73 #define tb_ctl_dbg_once(ctl, format, arg...) \
74 	dev_dbg_once(&(ctl)->nhi->pdev->dev, format, ## arg)
75 
76 static DECLARE_WAIT_QUEUE_HEAD(tb_cfg_request_cancel_queue);
77 /* Serializes access to request kref_get/put */
78 static DEFINE_MUTEX(tb_cfg_request_lock);
79 
80 /**
81  * tb_cfg_request_alloc() - Allocates a new config request
82  *
83  * This is refcounted object so when you are done with this, call
84  * tb_cfg_request_put() to it.
85  */
86 struct tb_cfg_request *tb_cfg_request_alloc(void)
87 {
88 	struct tb_cfg_request *req;
89 
90 	req = kzalloc(sizeof(*req), GFP_KERNEL);
91 	if (!req)
92 		return NULL;
93 
94 	kref_init(&req->kref);
95 
96 	return req;
97 }
98 
99 /**
100  * tb_cfg_request_get() - Increase refcount of a request
101  * @req: Request whose refcount is increased
102  */
103 void tb_cfg_request_get(struct tb_cfg_request *req)
104 {
105 	mutex_lock(&tb_cfg_request_lock);
106 	kref_get(&req->kref);
107 	mutex_unlock(&tb_cfg_request_lock);
108 }
109 
110 static void tb_cfg_request_destroy(struct kref *kref)
111 {
112 	struct tb_cfg_request *req = container_of(kref, typeof(*req), kref);
113 
114 	kfree(req);
115 }
116 
117 /**
118  * tb_cfg_request_put() - Decrease refcount and possibly release the request
119  * @req: Request whose refcount is decreased
120  *
121  * Call this function when you are done with the request. When refcount
122  * goes to %0 the object is released.
123  */
124 void tb_cfg_request_put(struct tb_cfg_request *req)
125 {
126 	mutex_lock(&tb_cfg_request_lock);
127 	kref_put(&req->kref, tb_cfg_request_destroy);
128 	mutex_unlock(&tb_cfg_request_lock);
129 }
130 
131 static int tb_cfg_request_enqueue(struct tb_ctl *ctl,
132 				  struct tb_cfg_request *req)
133 {
134 	WARN_ON(test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags));
135 	WARN_ON(req->ctl);
136 
137 	mutex_lock(&ctl->request_queue_lock);
138 	if (!ctl->running) {
139 		mutex_unlock(&ctl->request_queue_lock);
140 		return -ENOTCONN;
141 	}
142 	req->ctl = ctl;
143 	list_add_tail(&req->list, &ctl->request_queue);
144 	set_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
145 	mutex_unlock(&ctl->request_queue_lock);
146 	return 0;
147 }
148 
149 static void tb_cfg_request_dequeue(struct tb_cfg_request *req)
150 {
151 	struct tb_ctl *ctl = req->ctl;
152 
153 	mutex_lock(&ctl->request_queue_lock);
154 	list_del(&req->list);
155 	clear_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
156 	if (test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
157 		wake_up(&tb_cfg_request_cancel_queue);
158 	mutex_unlock(&ctl->request_queue_lock);
159 }
160 
161 static bool tb_cfg_request_is_active(struct tb_cfg_request *req)
162 {
163 	return test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
164 }
165 
166 static struct tb_cfg_request *
167 tb_cfg_request_find(struct tb_ctl *ctl, struct ctl_pkg *pkg)
168 {
169 	struct tb_cfg_request *req = NULL, *iter;
170 
171 	mutex_lock(&pkg->ctl->request_queue_lock);
172 	list_for_each_entry(iter, &pkg->ctl->request_queue, list) {
173 		tb_cfg_request_get(iter);
174 		if (iter->match(iter, pkg)) {
175 			req = iter;
176 			break;
177 		}
178 		tb_cfg_request_put(iter);
179 	}
180 	mutex_unlock(&pkg->ctl->request_queue_lock);
181 
182 	return req;
183 }
184 
185 /* utility functions */
186 
187 
188 static int check_header(const struct ctl_pkg *pkg, u32 len,
189 			enum tb_cfg_pkg_type type, u64 route)
190 {
191 	struct tb_cfg_header *header = pkg->buffer;
192 
193 	/* check frame, TODO: frame flags */
194 	if (WARN(len != pkg->frame.size,
195 			"wrong framesize (expected %#x, got %#x)\n",
196 			len, pkg->frame.size))
197 		return -EIO;
198 	if (WARN(type != pkg->frame.eof, "wrong eof (expected %#x, got %#x)\n",
199 			type, pkg->frame.eof))
200 		return -EIO;
201 	if (WARN(pkg->frame.sof, "wrong sof (expected 0x0, got %#x)\n",
202 			pkg->frame.sof))
203 		return -EIO;
204 
205 	/* check header */
206 	if (WARN(header->unknown != 1 << 9,
207 			"header->unknown is %#x\n", header->unknown))
208 		return -EIO;
209 	if (WARN(route != tb_cfg_get_route(header),
210 			"wrong route (expected %llx, got %llx)",
211 			route, tb_cfg_get_route(header)))
212 		return -EIO;
213 	return 0;
214 }
215 
216 static int check_config_address(struct tb_cfg_address addr,
217 				enum tb_cfg_space space, u32 offset,
218 				u32 length)
219 {
220 	if (WARN(addr.zero, "addr.zero is %#x\n", addr.zero))
221 		return -EIO;
222 	if (WARN(space != addr.space, "wrong space (expected %x, got %x\n)",
223 			space, addr.space))
224 		return -EIO;
225 	if (WARN(offset != addr.offset, "wrong offset (expected %x, got %x\n)",
226 			offset, addr.offset))
227 		return -EIO;
228 	if (WARN(length != addr.length, "wrong space (expected %x, got %x\n)",
229 			length, addr.length))
230 		return -EIO;
231 	/*
232 	 * We cannot check addr->port as it is set to the upstream port of the
233 	 * sender.
234 	 */
235 	return 0;
236 }
237 
238 static struct tb_cfg_result decode_error(const struct ctl_pkg *response)
239 {
240 	struct cfg_error_pkg *pkg = response->buffer;
241 	struct tb_cfg_result res = { 0 };
242 	res.response_route = tb_cfg_get_route(&pkg->header);
243 	res.response_port = 0;
244 	res.err = check_header(response, sizeof(*pkg), TB_CFG_PKG_ERROR,
245 			       tb_cfg_get_route(&pkg->header));
246 	if (res.err)
247 		return res;
248 
249 	res.err = 1;
250 	res.tb_error = pkg->error;
251 	res.response_port = pkg->port;
252 	return res;
253 
254 }
255 
256 static struct tb_cfg_result parse_header(const struct ctl_pkg *pkg, u32 len,
257 					 enum tb_cfg_pkg_type type, u64 route)
258 {
259 	struct tb_cfg_header *header = pkg->buffer;
260 	struct tb_cfg_result res = { 0 };
261 
262 	if (pkg->frame.eof == TB_CFG_PKG_ERROR)
263 		return decode_error(pkg);
264 
265 	res.response_port = 0; /* will be updated later for cfg_read/write */
266 	res.response_route = tb_cfg_get_route(header);
267 	res.err = check_header(pkg, len, type, route);
268 	return res;
269 }
270 
271 static void tb_cfg_print_error(struct tb_ctl *ctl, enum tb_cfg_space space,
272 			       const struct tb_cfg_result *res)
273 {
274 	WARN_ON(res->err != 1);
275 	switch (res->tb_error) {
276 	case TB_CFG_ERROR_PORT_NOT_CONNECTED:
277 		/* Port is not connected. This can happen during surprise
278 		 * removal. Do not warn. */
279 		return;
280 	case TB_CFG_ERROR_INVALID_CONFIG_SPACE:
281 		/*
282 		 * Invalid cfg_space/offset/length combination in
283 		 * cfg_read/cfg_write.
284 		 */
285 		tb_ctl_dbg_once(ctl, "%llx:%x: invalid config space (%u) or offset\n",
286 				res->response_route, res->response_port, space);
287 		return;
288 	case TB_CFG_ERROR_NO_SUCH_PORT:
289 		/*
290 		 * - The route contains a non-existent port.
291 		 * - The route contains a non-PHY port (e.g. PCIe).
292 		 * - The port in cfg_read/cfg_write does not exist.
293 		 */
294 		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Invalid port\n",
295 			res->response_route, res->response_port);
296 		return;
297 	case TB_CFG_ERROR_LOOP:
298 		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Route contains a loop\n",
299 			res->response_route, res->response_port);
300 		return;
301 	case TB_CFG_ERROR_LOCK:
302 		tb_ctl_warn(ctl, "%llx:%x: downstream port is locked\n",
303 			    res->response_route, res->response_port);
304 		return;
305 	default:
306 		/* 5,6,7,9 and 11 are also valid error codes */
307 		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Unknown error\n",
308 			res->response_route, res->response_port);
309 		return;
310 	}
311 }
312 
313 static __be32 tb_crc(const void *data, size_t len)
314 {
315 	return cpu_to_be32(~__crc32c_le(~0, data, len));
316 }
317 
318 static void tb_ctl_pkg_free(struct ctl_pkg *pkg)
319 {
320 	if (pkg) {
321 		dma_pool_free(pkg->ctl->frame_pool,
322 			      pkg->buffer, pkg->frame.buffer_phy);
323 		kfree(pkg);
324 	}
325 }
326 
327 static struct ctl_pkg *tb_ctl_pkg_alloc(struct tb_ctl *ctl)
328 {
329 	struct ctl_pkg *pkg = kzalloc(sizeof(*pkg), GFP_KERNEL);
330 	if (!pkg)
331 		return NULL;
332 	pkg->ctl = ctl;
333 	pkg->buffer = dma_pool_alloc(ctl->frame_pool, GFP_KERNEL,
334 				     &pkg->frame.buffer_phy);
335 	if (!pkg->buffer) {
336 		kfree(pkg);
337 		return NULL;
338 	}
339 	return pkg;
340 }
341 
342 
343 /* RX/TX handling */
344 
345 static void tb_ctl_tx_callback(struct tb_ring *ring, struct ring_frame *frame,
346 			       bool canceled)
347 {
348 	struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
349 	tb_ctl_pkg_free(pkg);
350 }
351 
352 /*
353  * tb_cfg_tx() - transmit a packet on the control channel
354  *
355  * len must be a multiple of four.
356  *
357  * Return: Returns 0 on success or an error code on failure.
358  */
359 static int tb_ctl_tx(struct tb_ctl *ctl, const void *data, size_t len,
360 		     enum tb_cfg_pkg_type type)
361 {
362 	int res;
363 	struct ctl_pkg *pkg;
364 	if (len % 4 != 0) { /* required for le->be conversion */
365 		tb_ctl_WARN(ctl, "TX: invalid size: %zu\n", len);
366 		return -EINVAL;
367 	}
368 	if (len > TB_FRAME_SIZE - 4) { /* checksum is 4 bytes */
369 		tb_ctl_WARN(ctl, "TX: packet too large: %zu/%d\n",
370 			    len, TB_FRAME_SIZE - 4);
371 		return -EINVAL;
372 	}
373 	pkg = tb_ctl_pkg_alloc(ctl);
374 	if (!pkg)
375 		return -ENOMEM;
376 	pkg->frame.callback = tb_ctl_tx_callback;
377 	pkg->frame.size = len + 4;
378 	pkg->frame.sof = type;
379 	pkg->frame.eof = type;
380 
381 	trace_tb_tx(ctl->index, type, data, len);
382 
383 	cpu_to_be32_array(pkg->buffer, data, len / 4);
384 	*(__be32 *) (pkg->buffer + len) = tb_crc(pkg->buffer, len);
385 
386 	res = tb_ring_tx(ctl->tx, &pkg->frame);
387 	if (res) /* ring is stopped */
388 		tb_ctl_pkg_free(pkg);
389 	return res;
390 }
391 
392 /*
393  * tb_ctl_handle_event() - acknowledge a plug event, invoke ctl->callback
394  */
395 static bool tb_ctl_handle_event(struct tb_ctl *ctl, enum tb_cfg_pkg_type type,
396 				struct ctl_pkg *pkg, size_t size)
397 {
398 	trace_tb_event(ctl->index, type, pkg->buffer, size);
399 	return ctl->callback(ctl->callback_data, type, pkg->buffer, size);
400 }
401 
402 static void tb_ctl_rx_submit(struct ctl_pkg *pkg)
403 {
404 	tb_ring_rx(pkg->ctl->rx, &pkg->frame); /*
405 					     * We ignore failures during stop.
406 					     * All rx packets are referenced
407 					     * from ctl->rx_packets, so we do
408 					     * not loose them.
409 					     */
410 }
411 
412 static int tb_async_error(const struct ctl_pkg *pkg)
413 {
414 	const struct cfg_error_pkg *error = pkg->buffer;
415 
416 	if (pkg->frame.eof != TB_CFG_PKG_ERROR)
417 		return false;
418 
419 	switch (error->error) {
420 	case TB_CFG_ERROR_LINK_ERROR:
421 	case TB_CFG_ERROR_HEC_ERROR_DETECTED:
422 	case TB_CFG_ERROR_FLOW_CONTROL_ERROR:
423 	case TB_CFG_ERROR_DP_BW:
424 	case TB_CFG_ERROR_ROP_CMPLT:
425 	case TB_CFG_ERROR_POP_CMPLT:
426 	case TB_CFG_ERROR_PCIE_WAKE:
427 	case TB_CFG_ERROR_DP_CON_CHANGE:
428 	case TB_CFG_ERROR_DPTX_DISCOVERY:
429 	case TB_CFG_ERROR_LINK_RECOVERY:
430 	case TB_CFG_ERROR_ASYM_LINK:
431 		return true;
432 
433 	default:
434 		return false;
435 	}
436 }
437 
438 static void tb_ctl_rx_callback(struct tb_ring *ring, struct ring_frame *frame,
439 			       bool canceled)
440 {
441 	struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
442 	struct tb_cfg_request *req;
443 	__be32 crc32;
444 
445 	if (canceled)
446 		return; /*
447 			 * ring is stopped, packet is referenced from
448 			 * ctl->rx_packets.
449 			 */
450 
451 	if (frame->size < 4 || frame->size % 4 != 0) {
452 		tb_ctl_err(pkg->ctl, "RX: invalid size %#x, dropping packet\n",
453 			   frame->size);
454 		goto rx;
455 	}
456 
457 	frame->size -= 4; /* remove checksum */
458 	crc32 = tb_crc(pkg->buffer, frame->size);
459 	be32_to_cpu_array(pkg->buffer, pkg->buffer, frame->size / 4);
460 
461 	switch (frame->eof) {
462 	case TB_CFG_PKG_READ:
463 	case TB_CFG_PKG_WRITE:
464 	case TB_CFG_PKG_ERROR:
465 	case TB_CFG_PKG_OVERRIDE:
466 	case TB_CFG_PKG_RESET:
467 		if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
468 			tb_ctl_err(pkg->ctl,
469 				   "RX: checksum mismatch, dropping packet\n");
470 			goto rx;
471 		}
472 		if (tb_async_error(pkg)) {
473 			tb_ctl_handle_event(pkg->ctl, frame->eof,
474 					    pkg, frame->size);
475 			goto rx;
476 		}
477 		break;
478 
479 	case TB_CFG_PKG_EVENT:
480 	case TB_CFG_PKG_XDOMAIN_RESP:
481 	case TB_CFG_PKG_XDOMAIN_REQ:
482 		if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
483 			tb_ctl_err(pkg->ctl,
484 				   "RX: checksum mismatch, dropping packet\n");
485 			goto rx;
486 		}
487 		fallthrough;
488 	case TB_CFG_PKG_ICM_EVENT:
489 		if (tb_ctl_handle_event(pkg->ctl, frame->eof, pkg, frame->size))
490 			goto rx;
491 		break;
492 
493 	default:
494 		break;
495 	}
496 
497 	/*
498 	 * The received packet will be processed only if there is an
499 	 * active request and that the packet is what is expected. This
500 	 * prevents packets such as replies coming after timeout has
501 	 * triggered from messing with the active requests.
502 	 */
503 	req = tb_cfg_request_find(pkg->ctl, pkg);
504 
505 	trace_tb_rx(pkg->ctl->index, frame->eof, pkg->buffer, frame->size, !req);
506 
507 	if (req) {
508 		if (req->copy(req, pkg))
509 			schedule_work(&req->work);
510 		tb_cfg_request_put(req);
511 	}
512 
513 rx:
514 	tb_ctl_rx_submit(pkg);
515 }
516 
517 static void tb_cfg_request_work(struct work_struct *work)
518 {
519 	struct tb_cfg_request *req = container_of(work, typeof(*req), work);
520 
521 	if (!test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
522 		req->callback(req->callback_data);
523 
524 	tb_cfg_request_dequeue(req);
525 	tb_cfg_request_put(req);
526 }
527 
528 /**
529  * tb_cfg_request() - Start control request not waiting for it to complete
530  * @ctl: Control channel to use
531  * @req: Request to start
532  * @callback: Callback called when the request is completed
533  * @callback_data: Data to be passed to @callback
534  *
535  * This queues @req on the given control channel without waiting for it
536  * to complete. When the request completes @callback is called.
537  */
538 int tb_cfg_request(struct tb_ctl *ctl, struct tb_cfg_request *req,
539 		   void (*callback)(void *), void *callback_data)
540 {
541 	int ret;
542 
543 	req->flags = 0;
544 	req->callback = callback;
545 	req->callback_data = callback_data;
546 	INIT_WORK(&req->work, tb_cfg_request_work);
547 	INIT_LIST_HEAD(&req->list);
548 
549 	tb_cfg_request_get(req);
550 	ret = tb_cfg_request_enqueue(ctl, req);
551 	if (ret)
552 		goto err_put;
553 
554 	ret = tb_ctl_tx(ctl, req->request, req->request_size,
555 			req->request_type);
556 	if (ret)
557 		goto err_dequeue;
558 
559 	if (!req->response)
560 		schedule_work(&req->work);
561 
562 	return 0;
563 
564 err_dequeue:
565 	tb_cfg_request_dequeue(req);
566 err_put:
567 	tb_cfg_request_put(req);
568 
569 	return ret;
570 }
571 
572 /**
573  * tb_cfg_request_cancel() - Cancel a control request
574  * @req: Request to cancel
575  * @err: Error to assign to the request
576  *
577  * This function can be used to cancel ongoing request. It will wait
578  * until the request is not active anymore.
579  */
580 void tb_cfg_request_cancel(struct tb_cfg_request *req, int err)
581 {
582 	set_bit(TB_CFG_REQUEST_CANCELED, &req->flags);
583 	schedule_work(&req->work);
584 	wait_event(tb_cfg_request_cancel_queue, !tb_cfg_request_is_active(req));
585 	req->result.err = err;
586 }
587 
588 static void tb_cfg_request_complete(void *data)
589 {
590 	complete(data);
591 }
592 
593 /**
594  * tb_cfg_request_sync() - Start control request and wait until it completes
595  * @ctl: Control channel to use
596  * @req: Request to start
597  * @timeout_msec: Timeout how long to wait @req to complete
598  *
599  * Starts a control request and waits until it completes. If timeout
600  * triggers the request is canceled before function returns. Note the
601  * caller needs to make sure only one message for given switch is active
602  * at a time.
603  */
604 struct tb_cfg_result tb_cfg_request_sync(struct tb_ctl *ctl,
605 					 struct tb_cfg_request *req,
606 					 int timeout_msec)
607 {
608 	unsigned long timeout = msecs_to_jiffies(timeout_msec);
609 	struct tb_cfg_result res = { 0 };
610 	DECLARE_COMPLETION_ONSTACK(done);
611 	int ret;
612 
613 	ret = tb_cfg_request(ctl, req, tb_cfg_request_complete, &done);
614 	if (ret) {
615 		res.err = ret;
616 		return res;
617 	}
618 
619 	if (!wait_for_completion_timeout(&done, timeout))
620 		tb_cfg_request_cancel(req, -ETIMEDOUT);
621 
622 	flush_work(&req->work);
623 
624 	return req->result;
625 }
626 
627 /* public interface, alloc/start/stop/free */
628 
629 /**
630  * tb_ctl_alloc() - allocate a control channel
631  * @nhi: Pointer to NHI
632  * @index: Domain number
633  * @timeout_msec: Default timeout used with non-raw control messages
634  * @cb: Callback called for plug events
635  * @cb_data: Data passed to @cb
636  *
637  * cb will be invoked once for every hot plug event.
638  *
639  * Return: Returns a pointer on success or NULL on failure.
640  */
641 struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, int index, int timeout_msec,
642 			    event_cb cb, void *cb_data)
643 {
644 	int i;
645 	struct tb_ctl *ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
646 	if (!ctl)
647 		return NULL;
648 
649 	ctl->nhi = nhi;
650 	ctl->index = index;
651 	ctl->timeout_msec = timeout_msec;
652 	ctl->callback = cb;
653 	ctl->callback_data = cb_data;
654 
655 	mutex_init(&ctl->request_queue_lock);
656 	INIT_LIST_HEAD(&ctl->request_queue);
657 	ctl->frame_pool = dma_pool_create("thunderbolt_ctl", &nhi->pdev->dev,
658 					 TB_FRAME_SIZE, 4, 0);
659 	if (!ctl->frame_pool)
660 		goto err;
661 
662 	ctl->tx = tb_ring_alloc_tx(nhi, 0, 10, RING_FLAG_NO_SUSPEND);
663 	if (!ctl->tx)
664 		goto err;
665 
666 	ctl->rx = tb_ring_alloc_rx(nhi, 0, 10, RING_FLAG_NO_SUSPEND, 0, 0xffff,
667 				   0xffff, NULL, NULL);
668 	if (!ctl->rx)
669 		goto err;
670 
671 	for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++) {
672 		ctl->rx_packets[i] = tb_ctl_pkg_alloc(ctl);
673 		if (!ctl->rx_packets[i])
674 			goto err;
675 		ctl->rx_packets[i]->frame.callback = tb_ctl_rx_callback;
676 	}
677 
678 	tb_ctl_dbg(ctl, "control channel created\n");
679 	return ctl;
680 err:
681 	tb_ctl_free(ctl);
682 	return NULL;
683 }
684 
685 /**
686  * tb_ctl_free() - free a control channel
687  * @ctl: Control channel to free
688  *
689  * Must be called after tb_ctl_stop.
690  *
691  * Must NOT be called from ctl->callback.
692  */
693 void tb_ctl_free(struct tb_ctl *ctl)
694 {
695 	int i;
696 
697 	if (!ctl)
698 		return;
699 
700 	if (ctl->rx)
701 		tb_ring_free(ctl->rx);
702 	if (ctl->tx)
703 		tb_ring_free(ctl->tx);
704 
705 	/* free RX packets */
706 	for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
707 		tb_ctl_pkg_free(ctl->rx_packets[i]);
708 
709 
710 	dma_pool_destroy(ctl->frame_pool);
711 	kfree(ctl);
712 }
713 
714 /**
715  * tb_ctl_start() - start/resume the control channel
716  * @ctl: Control channel to start
717  */
718 void tb_ctl_start(struct tb_ctl *ctl)
719 {
720 	int i;
721 	tb_ctl_dbg(ctl, "control channel starting...\n");
722 	tb_ring_start(ctl->tx); /* is used to ack hotplug packets, start first */
723 	tb_ring_start(ctl->rx);
724 	for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
725 		tb_ctl_rx_submit(ctl->rx_packets[i]);
726 
727 	ctl->running = true;
728 }
729 
730 /**
731  * tb_ctl_stop() - pause the control channel
732  * @ctl: Control channel to stop
733  *
734  * All invocations of ctl->callback will have finished after this method
735  * returns.
736  *
737  * Must NOT be called from ctl->callback.
738  */
739 void tb_ctl_stop(struct tb_ctl *ctl)
740 {
741 	mutex_lock(&ctl->request_queue_lock);
742 	ctl->running = false;
743 	mutex_unlock(&ctl->request_queue_lock);
744 
745 	tb_ring_stop(ctl->rx);
746 	tb_ring_stop(ctl->tx);
747 
748 	if (!list_empty(&ctl->request_queue))
749 		tb_ctl_WARN(ctl, "dangling request in request_queue\n");
750 	INIT_LIST_HEAD(&ctl->request_queue);
751 	tb_ctl_dbg(ctl, "control channel stopped\n");
752 }
753 
754 /* public interface, commands */
755 
756 /**
757  * tb_cfg_ack_notification() - Ack notification
758  * @ctl: Control channel to use
759  * @route: Router that originated the event
760  * @error: Pointer to the notification package
761  *
762  * Call this as response for non-plug notification to ack it. Returns
763  * %0 on success or an error code on failure.
764  */
765 int tb_cfg_ack_notification(struct tb_ctl *ctl, u64 route,
766 			    const struct cfg_error_pkg *error)
767 {
768 	struct cfg_ack_pkg pkg = {
769 		.header = tb_cfg_make_header(route),
770 	};
771 	const char *name;
772 
773 	switch (error->error) {
774 	case TB_CFG_ERROR_LINK_ERROR:
775 		name = "link error";
776 		break;
777 	case TB_CFG_ERROR_HEC_ERROR_DETECTED:
778 		name = "HEC error";
779 		break;
780 	case TB_CFG_ERROR_FLOW_CONTROL_ERROR:
781 		name = "flow control error";
782 		break;
783 	case TB_CFG_ERROR_DP_BW:
784 		name = "DP_BW";
785 		break;
786 	case TB_CFG_ERROR_ROP_CMPLT:
787 		name = "router operation completion";
788 		break;
789 	case TB_CFG_ERROR_POP_CMPLT:
790 		name = "port operation completion";
791 		break;
792 	case TB_CFG_ERROR_PCIE_WAKE:
793 		name = "PCIe wake";
794 		break;
795 	case TB_CFG_ERROR_DP_CON_CHANGE:
796 		name = "DP connector change";
797 		break;
798 	case TB_CFG_ERROR_DPTX_DISCOVERY:
799 		name = "DPTX discovery";
800 		break;
801 	case TB_CFG_ERROR_LINK_RECOVERY:
802 		name = "link recovery";
803 		break;
804 	case TB_CFG_ERROR_ASYM_LINK:
805 		name = "asymmetric link";
806 		break;
807 	default:
808 		name = "unknown";
809 		break;
810 	}
811 
812 	tb_ctl_dbg(ctl, "acking %s (%#x) notification on %llx\n", name,
813 		   error->error, route);
814 
815 	return tb_ctl_tx(ctl, &pkg, sizeof(pkg), TB_CFG_PKG_NOTIFY_ACK);
816 }
817 
818 /**
819  * tb_cfg_ack_plug() - Ack hot plug/unplug event
820  * @ctl: Control channel to use
821  * @route: Router that originated the event
822  * @port: Port where the hot plug/unplug happened
823  * @unplug: Ack hot plug or unplug
824  *
825  * Call this as response for hot plug/unplug event to ack it.
826  * Returns %0 on success or an error code on failure.
827  */
828 int tb_cfg_ack_plug(struct tb_ctl *ctl, u64 route, u32 port, bool unplug)
829 {
830 	struct cfg_error_pkg pkg = {
831 		.header = tb_cfg_make_header(route),
832 		.port = port,
833 		.error = TB_CFG_ERROR_ACK_PLUG_EVENT,
834 		.pg = unplug ? TB_CFG_ERROR_PG_HOT_UNPLUG
835 			     : TB_CFG_ERROR_PG_HOT_PLUG,
836 	};
837 	tb_ctl_dbg(ctl, "acking hot %splug event on %llx:%u\n",
838 		   unplug ? "un" : "", route, port);
839 	return tb_ctl_tx(ctl, &pkg, sizeof(pkg), TB_CFG_PKG_ERROR);
840 }
841 
842 static bool tb_cfg_match(const struct tb_cfg_request *req,
843 			 const struct ctl_pkg *pkg)
844 {
845 	u64 route = tb_cfg_get_route(pkg->buffer) & ~BIT_ULL(63);
846 
847 	if (pkg->frame.eof == TB_CFG_PKG_ERROR)
848 		return true;
849 
850 	if (pkg->frame.eof != req->response_type)
851 		return false;
852 	if (route != tb_cfg_get_route(req->request))
853 		return false;
854 	if (pkg->frame.size != req->response_size)
855 		return false;
856 
857 	if (pkg->frame.eof == TB_CFG_PKG_READ ||
858 	    pkg->frame.eof == TB_CFG_PKG_WRITE) {
859 		const struct cfg_read_pkg *req_hdr = req->request;
860 		const struct cfg_read_pkg *res_hdr = pkg->buffer;
861 
862 		if (req_hdr->addr.seq != res_hdr->addr.seq)
863 			return false;
864 	}
865 
866 	return true;
867 }
868 
869 static bool tb_cfg_copy(struct tb_cfg_request *req, const struct ctl_pkg *pkg)
870 {
871 	struct tb_cfg_result res;
872 
873 	/* Now make sure it is in expected format */
874 	res = parse_header(pkg, req->response_size, req->response_type,
875 			   tb_cfg_get_route(req->request));
876 	if (!res.err)
877 		memcpy(req->response, pkg->buffer, req->response_size);
878 
879 	req->result = res;
880 
881 	/* Always complete when first response is received */
882 	return true;
883 }
884 
885 /**
886  * tb_cfg_reset() - send a reset packet and wait for a response
887  * @ctl: Control channel pointer
888  * @route: Router string for the router to send reset
889  *
890  * If the switch at route is incorrectly configured then we will not receive a
891  * reply (even though the switch will reset). The caller should check for
892  * -ETIMEDOUT and attempt to reconfigure the switch.
893  */
894 struct tb_cfg_result tb_cfg_reset(struct tb_ctl *ctl, u64 route)
895 {
896 	struct cfg_reset_pkg request = { .header = tb_cfg_make_header(route) };
897 	struct tb_cfg_result res = { 0 };
898 	struct tb_cfg_header reply;
899 	struct tb_cfg_request *req;
900 
901 	req = tb_cfg_request_alloc();
902 	if (!req) {
903 		res.err = -ENOMEM;
904 		return res;
905 	}
906 
907 	req->match = tb_cfg_match;
908 	req->copy = tb_cfg_copy;
909 	req->request = &request;
910 	req->request_size = sizeof(request);
911 	req->request_type = TB_CFG_PKG_RESET;
912 	req->response = &reply;
913 	req->response_size = sizeof(reply);
914 	req->response_type = TB_CFG_PKG_RESET;
915 
916 	res = tb_cfg_request_sync(ctl, req, ctl->timeout_msec);
917 
918 	tb_cfg_request_put(req);
919 
920 	return res;
921 }
922 
923 /**
924  * tb_cfg_read_raw() - read from config space into buffer
925  * @ctl: Pointer to the control channel
926  * @buffer: Buffer where the data is read
927  * @route: Route string of the router
928  * @port: Port number when reading from %TB_CFG_PORT, %0 otherwise
929  * @space: Config space selector
930  * @offset: Dword word offset of the register to start reading
931  * @length: Number of dwords to read
932  * @timeout_msec: Timeout in ms how long to wait for the response
933  *
934  * Reads from router config space without translating the possible error.
935  */
936 struct tb_cfg_result tb_cfg_read_raw(struct tb_ctl *ctl, void *buffer,
937 		u64 route, u32 port, enum tb_cfg_space space,
938 		u32 offset, u32 length, int timeout_msec)
939 {
940 	struct tb_cfg_result res = { 0 };
941 	struct cfg_read_pkg request = {
942 		.header = tb_cfg_make_header(route),
943 		.addr = {
944 			.port = port,
945 			.space = space,
946 			.offset = offset,
947 			.length = length,
948 		},
949 	};
950 	struct cfg_write_pkg reply;
951 	int retries = 0;
952 
953 	while (retries < TB_CTL_RETRIES) {
954 		struct tb_cfg_request *req;
955 
956 		req = tb_cfg_request_alloc();
957 		if (!req) {
958 			res.err = -ENOMEM;
959 			return res;
960 		}
961 
962 		request.addr.seq = retries++;
963 
964 		req->match = tb_cfg_match;
965 		req->copy = tb_cfg_copy;
966 		req->request = &request;
967 		req->request_size = sizeof(request);
968 		req->request_type = TB_CFG_PKG_READ;
969 		req->response = &reply;
970 		req->response_size = 12 + 4 * length;
971 		req->response_type = TB_CFG_PKG_READ;
972 
973 		res = tb_cfg_request_sync(ctl, req, timeout_msec);
974 
975 		tb_cfg_request_put(req);
976 
977 		if (res.err != -ETIMEDOUT)
978 			break;
979 
980 		/* Wait a bit (arbitrary time) until we send a retry */
981 		usleep_range(10, 100);
982 	}
983 
984 	if (res.err)
985 		return res;
986 
987 	res.response_port = reply.addr.port;
988 	res.err = check_config_address(reply.addr, space, offset, length);
989 	if (!res.err)
990 		memcpy(buffer, &reply.data, 4 * length);
991 	return res;
992 }
993 
994 /**
995  * tb_cfg_write_raw() - write from buffer into config space
996  * @ctl: Pointer to the control channel
997  * @buffer: Data to write
998  * @route: Route string of the router
999  * @port: Port number when writing to %TB_CFG_PORT, %0 otherwise
1000  * @space: Config space selector
1001  * @offset: Dword word offset of the register to start writing
1002  * @length: Number of dwords to write
1003  * @timeout_msec: Timeout in ms how long to wait for the response
1004  *
1005  * Writes to router config space without translating the possible error.
1006  */
1007 struct tb_cfg_result tb_cfg_write_raw(struct tb_ctl *ctl, const void *buffer,
1008 		u64 route, u32 port, enum tb_cfg_space space,
1009 		u32 offset, u32 length, int timeout_msec)
1010 {
1011 	struct tb_cfg_result res = { 0 };
1012 	struct cfg_write_pkg request = {
1013 		.header = tb_cfg_make_header(route),
1014 		.addr = {
1015 			.port = port,
1016 			.space = space,
1017 			.offset = offset,
1018 			.length = length,
1019 		},
1020 	};
1021 	struct cfg_read_pkg reply;
1022 	int retries = 0;
1023 
1024 	memcpy(&request.data, buffer, length * 4);
1025 
1026 	while (retries < TB_CTL_RETRIES) {
1027 		struct tb_cfg_request *req;
1028 
1029 		req = tb_cfg_request_alloc();
1030 		if (!req) {
1031 			res.err = -ENOMEM;
1032 			return res;
1033 		}
1034 
1035 		request.addr.seq = retries++;
1036 
1037 		req->match = tb_cfg_match;
1038 		req->copy = tb_cfg_copy;
1039 		req->request = &request;
1040 		req->request_size = 12 + 4 * length;
1041 		req->request_type = TB_CFG_PKG_WRITE;
1042 		req->response = &reply;
1043 		req->response_size = sizeof(reply);
1044 		req->response_type = TB_CFG_PKG_WRITE;
1045 
1046 		res = tb_cfg_request_sync(ctl, req, timeout_msec);
1047 
1048 		tb_cfg_request_put(req);
1049 
1050 		if (res.err != -ETIMEDOUT)
1051 			break;
1052 
1053 		/* Wait a bit (arbitrary time) until we send a retry */
1054 		usleep_range(10, 100);
1055 	}
1056 
1057 	if (res.err)
1058 		return res;
1059 
1060 	res.response_port = reply.addr.port;
1061 	res.err = check_config_address(reply.addr, space, offset, length);
1062 	return res;
1063 }
1064 
1065 static int tb_cfg_get_error(struct tb_ctl *ctl, enum tb_cfg_space space,
1066 			    const struct tb_cfg_result *res)
1067 {
1068 	/*
1069 	 * For unimplemented ports access to port config space may return
1070 	 * TB_CFG_ERROR_INVALID_CONFIG_SPACE (alternatively their type is
1071 	 * set to TB_TYPE_INACTIVE). In the former case return -ENODEV so
1072 	 * that the caller can mark the port as disabled.
1073 	 */
1074 	if (space == TB_CFG_PORT &&
1075 	    res->tb_error == TB_CFG_ERROR_INVALID_CONFIG_SPACE)
1076 		return -ENODEV;
1077 
1078 	tb_cfg_print_error(ctl, space, res);
1079 
1080 	if (res->tb_error == TB_CFG_ERROR_LOCK)
1081 		return -EACCES;
1082 	if (res->tb_error == TB_CFG_ERROR_PORT_NOT_CONNECTED)
1083 		return -ENOTCONN;
1084 
1085 	return -EIO;
1086 }
1087 
1088 int tb_cfg_read(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
1089 		enum tb_cfg_space space, u32 offset, u32 length)
1090 {
1091 	struct tb_cfg_result res = tb_cfg_read_raw(ctl, buffer, route, port,
1092 			space, offset, length, ctl->timeout_msec);
1093 	switch (res.err) {
1094 	case 0:
1095 		/* Success */
1096 		break;
1097 
1098 	case 1:
1099 		/* Thunderbolt error, tb_error holds the actual number */
1100 		return tb_cfg_get_error(ctl, space, &res);
1101 
1102 	case -ETIMEDOUT:
1103 		tb_ctl_warn(ctl, "%llx: timeout reading config space %u from %#x\n",
1104 			    route, space, offset);
1105 		break;
1106 
1107 	default:
1108 		WARN(1, "tb_cfg_read: %d\n", res.err);
1109 		break;
1110 	}
1111 	return res.err;
1112 }
1113 
1114 int tb_cfg_write(struct tb_ctl *ctl, const void *buffer, u64 route, u32 port,
1115 		 enum tb_cfg_space space, u32 offset, u32 length)
1116 {
1117 	struct tb_cfg_result res = tb_cfg_write_raw(ctl, buffer, route, port,
1118 			space, offset, length, ctl->timeout_msec);
1119 	switch (res.err) {
1120 	case 0:
1121 		/* Success */
1122 		break;
1123 
1124 	case 1:
1125 		/* Thunderbolt error, tb_error holds the actual number */
1126 		return tb_cfg_get_error(ctl, space, &res);
1127 
1128 	case -ETIMEDOUT:
1129 		tb_ctl_warn(ctl, "%llx: timeout writing config space %u to %#x\n",
1130 			    route, space, offset);
1131 		break;
1132 
1133 	default:
1134 		WARN(1, "tb_cfg_write: %d\n", res.err);
1135 		break;
1136 	}
1137 	return res.err;
1138 }
1139 
1140 /**
1141  * tb_cfg_get_upstream_port() - get upstream port number of switch at route
1142  * @ctl: Pointer to the control channel
1143  * @route: Route string of the router
1144  *
1145  * Reads the first dword from the switches TB_CFG_SWITCH config area and
1146  * returns the port number from which the reply originated.
1147  *
1148  * Return: Returns the upstream port number on success or an error code on
1149  * failure.
1150  */
1151 int tb_cfg_get_upstream_port(struct tb_ctl *ctl, u64 route)
1152 {
1153 	u32 dummy;
1154 	struct tb_cfg_result res = tb_cfg_read_raw(ctl, &dummy, route, 0,
1155 						   TB_CFG_SWITCH, 0, 1,
1156 						   ctl->timeout_msec);
1157 	if (res.err == 1)
1158 		return -EIO;
1159 	if (res.err)
1160 		return res.err;
1161 	return res.response_port;
1162 }
1163