xref: /linux/drivers/thunderbolt/ctl.c (revision 79790b6818e96c58fe2bffee1b418c16e64e7b80)
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 static DECLARE_WAIT_QUEUE_HEAD(tb_cfg_request_cancel_queue);
74 /* Serializes access to request kref_get/put */
75 static DEFINE_MUTEX(tb_cfg_request_lock);
76 
77 /**
78  * tb_cfg_request_alloc() - Allocates a new config request
79  *
80  * This is refcounted object so when you are done with this, call
81  * tb_cfg_request_put() to it.
82  */
tb_cfg_request_alloc(void)83 struct tb_cfg_request *tb_cfg_request_alloc(void)
84 {
85 	struct tb_cfg_request *req;
86 
87 	req = kzalloc(sizeof(*req), GFP_KERNEL);
88 	if (!req)
89 		return NULL;
90 
91 	kref_init(&req->kref);
92 
93 	return req;
94 }
95 
96 /**
97  * tb_cfg_request_get() - Increase refcount of a request
98  * @req: Request whose refcount is increased
99  */
tb_cfg_request_get(struct tb_cfg_request * req)100 void tb_cfg_request_get(struct tb_cfg_request *req)
101 {
102 	mutex_lock(&tb_cfg_request_lock);
103 	kref_get(&req->kref);
104 	mutex_unlock(&tb_cfg_request_lock);
105 }
106 
tb_cfg_request_destroy(struct kref * kref)107 static void tb_cfg_request_destroy(struct kref *kref)
108 {
109 	struct tb_cfg_request *req = container_of(kref, typeof(*req), kref);
110 
111 	kfree(req);
112 }
113 
114 /**
115  * tb_cfg_request_put() - Decrease refcount and possibly release the request
116  * @req: Request whose refcount is decreased
117  *
118  * Call this function when you are done with the request. When refcount
119  * goes to %0 the object is released.
120  */
tb_cfg_request_put(struct tb_cfg_request * req)121 void tb_cfg_request_put(struct tb_cfg_request *req)
122 {
123 	mutex_lock(&tb_cfg_request_lock);
124 	kref_put(&req->kref, tb_cfg_request_destroy);
125 	mutex_unlock(&tb_cfg_request_lock);
126 }
127 
tb_cfg_request_enqueue(struct tb_ctl * ctl,struct tb_cfg_request * req)128 static int tb_cfg_request_enqueue(struct tb_ctl *ctl,
129 				  struct tb_cfg_request *req)
130 {
131 	WARN_ON(test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags));
132 	WARN_ON(req->ctl);
133 
134 	mutex_lock(&ctl->request_queue_lock);
135 	if (!ctl->running) {
136 		mutex_unlock(&ctl->request_queue_lock);
137 		return -ENOTCONN;
138 	}
139 	req->ctl = ctl;
140 	list_add_tail(&req->list, &ctl->request_queue);
141 	set_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
142 	mutex_unlock(&ctl->request_queue_lock);
143 	return 0;
144 }
145 
tb_cfg_request_dequeue(struct tb_cfg_request * req)146 static void tb_cfg_request_dequeue(struct tb_cfg_request *req)
147 {
148 	struct tb_ctl *ctl = req->ctl;
149 
150 	mutex_lock(&ctl->request_queue_lock);
151 	list_del(&req->list);
152 	clear_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
153 	if (test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
154 		wake_up(&tb_cfg_request_cancel_queue);
155 	mutex_unlock(&ctl->request_queue_lock);
156 }
157 
tb_cfg_request_is_active(struct tb_cfg_request * req)158 static bool tb_cfg_request_is_active(struct tb_cfg_request *req)
159 {
160 	return test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
161 }
162 
163 static struct tb_cfg_request *
tb_cfg_request_find(struct tb_ctl * ctl,struct ctl_pkg * pkg)164 tb_cfg_request_find(struct tb_ctl *ctl, struct ctl_pkg *pkg)
165 {
166 	struct tb_cfg_request *req = NULL, *iter;
167 
168 	mutex_lock(&pkg->ctl->request_queue_lock);
169 	list_for_each_entry(iter, &pkg->ctl->request_queue, list) {
170 		tb_cfg_request_get(iter);
171 		if (iter->match(iter, pkg)) {
172 			req = iter;
173 			break;
174 		}
175 		tb_cfg_request_put(iter);
176 	}
177 	mutex_unlock(&pkg->ctl->request_queue_lock);
178 
179 	return req;
180 }
181 
182 /* utility functions */
183 
184 
check_header(const struct ctl_pkg * pkg,u32 len,enum tb_cfg_pkg_type type,u64 route)185 static int check_header(const struct ctl_pkg *pkg, u32 len,
186 			enum tb_cfg_pkg_type type, u64 route)
187 {
188 	struct tb_cfg_header *header = pkg->buffer;
189 
190 	/* check frame, TODO: frame flags */
191 	if (WARN(len != pkg->frame.size,
192 			"wrong framesize (expected %#x, got %#x)\n",
193 			len, pkg->frame.size))
194 		return -EIO;
195 	if (WARN(type != pkg->frame.eof, "wrong eof (expected %#x, got %#x)\n",
196 			type, pkg->frame.eof))
197 		return -EIO;
198 	if (WARN(pkg->frame.sof, "wrong sof (expected 0x0, got %#x)\n",
199 			pkg->frame.sof))
200 		return -EIO;
201 
202 	/* check header */
203 	if (WARN(header->unknown != 1 << 9,
204 			"header->unknown is %#x\n", header->unknown))
205 		return -EIO;
206 	if (WARN(route != tb_cfg_get_route(header),
207 			"wrong route (expected %llx, got %llx)",
208 			route, tb_cfg_get_route(header)))
209 		return -EIO;
210 	return 0;
211 }
212 
check_config_address(struct tb_cfg_address addr,enum tb_cfg_space space,u32 offset,u32 length)213 static int check_config_address(struct tb_cfg_address addr,
214 				enum tb_cfg_space space, u32 offset,
215 				u32 length)
216 {
217 	if (WARN(addr.zero, "addr.zero is %#x\n", addr.zero))
218 		return -EIO;
219 	if (WARN(space != addr.space, "wrong space (expected %x, got %x\n)",
220 			space, addr.space))
221 		return -EIO;
222 	if (WARN(offset != addr.offset, "wrong offset (expected %x, got %x\n)",
223 			offset, addr.offset))
224 		return -EIO;
225 	if (WARN(length != addr.length, "wrong space (expected %x, got %x\n)",
226 			length, addr.length))
227 		return -EIO;
228 	/*
229 	 * We cannot check addr->port as it is set to the upstream port of the
230 	 * sender.
231 	 */
232 	return 0;
233 }
234 
decode_error(const struct ctl_pkg * response)235 static struct tb_cfg_result decode_error(const struct ctl_pkg *response)
236 {
237 	struct cfg_error_pkg *pkg = response->buffer;
238 	struct tb_cfg_result res = { 0 };
239 	res.response_route = tb_cfg_get_route(&pkg->header);
240 	res.response_port = 0;
241 	res.err = check_header(response, sizeof(*pkg), TB_CFG_PKG_ERROR,
242 			       tb_cfg_get_route(&pkg->header));
243 	if (res.err)
244 		return res;
245 
246 	res.err = 1;
247 	res.tb_error = pkg->error;
248 	res.response_port = pkg->port;
249 	return res;
250 
251 }
252 
parse_header(const struct ctl_pkg * pkg,u32 len,enum tb_cfg_pkg_type type,u64 route)253 static struct tb_cfg_result parse_header(const struct ctl_pkg *pkg, u32 len,
254 					 enum tb_cfg_pkg_type type, u64 route)
255 {
256 	struct tb_cfg_header *header = pkg->buffer;
257 	struct tb_cfg_result res = { 0 };
258 
259 	if (pkg->frame.eof == TB_CFG_PKG_ERROR)
260 		return decode_error(pkg);
261 
262 	res.response_port = 0; /* will be updated later for cfg_read/write */
263 	res.response_route = tb_cfg_get_route(header);
264 	res.err = check_header(pkg, len, type, route);
265 	return res;
266 }
267 
tb_cfg_print_error(struct tb_ctl * ctl,const struct tb_cfg_result * res)268 static void tb_cfg_print_error(struct tb_ctl *ctl,
269 			       const struct tb_cfg_result *res)
270 {
271 	WARN_ON(res->err != 1);
272 	switch (res->tb_error) {
273 	case TB_CFG_ERROR_PORT_NOT_CONNECTED:
274 		/* Port is not connected. This can happen during surprise
275 		 * removal. Do not warn. */
276 		return;
277 	case TB_CFG_ERROR_INVALID_CONFIG_SPACE:
278 		/*
279 		 * Invalid cfg_space/offset/length combination in
280 		 * cfg_read/cfg_write.
281 		 */
282 		tb_ctl_dbg(ctl, "%llx:%x: invalid config space or offset\n",
283 			   res->response_route, res->response_port);
284 		return;
285 	case TB_CFG_ERROR_NO_SUCH_PORT:
286 		/*
287 		 * - The route contains a non-existent port.
288 		 * - The route contains a non-PHY port (e.g. PCIe).
289 		 * - The port in cfg_read/cfg_write does not exist.
290 		 */
291 		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Invalid port\n",
292 			res->response_route, res->response_port);
293 		return;
294 	case TB_CFG_ERROR_LOOP:
295 		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Route contains a loop\n",
296 			res->response_route, res->response_port);
297 		return;
298 	case TB_CFG_ERROR_LOCK:
299 		tb_ctl_warn(ctl, "%llx:%x: downstream port is locked\n",
300 			    res->response_route, res->response_port);
301 		return;
302 	default:
303 		/* 5,6,7,9 and 11 are also valid error codes */
304 		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Unknown error\n",
305 			res->response_route, res->response_port);
306 		return;
307 	}
308 }
309 
tb_crc(const void * data,size_t len)310 static __be32 tb_crc(const void *data, size_t len)
311 {
312 	return cpu_to_be32(~__crc32c_le(~0, data, len));
313 }
314 
tb_ctl_pkg_free(struct ctl_pkg * pkg)315 static void tb_ctl_pkg_free(struct ctl_pkg *pkg)
316 {
317 	if (pkg) {
318 		dma_pool_free(pkg->ctl->frame_pool,
319 			      pkg->buffer, pkg->frame.buffer_phy);
320 		kfree(pkg);
321 	}
322 }
323 
tb_ctl_pkg_alloc(struct tb_ctl * ctl)324 static struct ctl_pkg *tb_ctl_pkg_alloc(struct tb_ctl *ctl)
325 {
326 	struct ctl_pkg *pkg = kzalloc(sizeof(*pkg), GFP_KERNEL);
327 	if (!pkg)
328 		return NULL;
329 	pkg->ctl = ctl;
330 	pkg->buffer = dma_pool_alloc(ctl->frame_pool, GFP_KERNEL,
331 				     &pkg->frame.buffer_phy);
332 	if (!pkg->buffer) {
333 		kfree(pkg);
334 		return NULL;
335 	}
336 	return pkg;
337 }
338 
339 
340 /* RX/TX handling */
341 
tb_ctl_tx_callback(struct tb_ring * ring,struct ring_frame * frame,bool canceled)342 static void tb_ctl_tx_callback(struct tb_ring *ring, struct ring_frame *frame,
343 			       bool canceled)
344 {
345 	struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
346 	tb_ctl_pkg_free(pkg);
347 }
348 
349 /*
350  * tb_cfg_tx() - transmit a packet on the control channel
351  *
352  * len must be a multiple of four.
353  *
354  * Return: Returns 0 on success or an error code on failure.
355  */
tb_ctl_tx(struct tb_ctl * ctl,const void * data,size_t len,enum tb_cfg_pkg_type type)356 static int tb_ctl_tx(struct tb_ctl *ctl, const void *data, size_t len,
357 		     enum tb_cfg_pkg_type type)
358 {
359 	int res;
360 	struct ctl_pkg *pkg;
361 	if (len % 4 != 0) { /* required for le->be conversion */
362 		tb_ctl_WARN(ctl, "TX: invalid size: %zu\n", len);
363 		return -EINVAL;
364 	}
365 	if (len > TB_FRAME_SIZE - 4) { /* checksum is 4 bytes */
366 		tb_ctl_WARN(ctl, "TX: packet too large: %zu/%d\n",
367 			    len, TB_FRAME_SIZE - 4);
368 		return -EINVAL;
369 	}
370 	pkg = tb_ctl_pkg_alloc(ctl);
371 	if (!pkg)
372 		return -ENOMEM;
373 	pkg->frame.callback = tb_ctl_tx_callback;
374 	pkg->frame.size = len + 4;
375 	pkg->frame.sof = type;
376 	pkg->frame.eof = type;
377 
378 	trace_tb_tx(ctl->index, type, data, len);
379 
380 	cpu_to_be32_array(pkg->buffer, data, len / 4);
381 	*(__be32 *) (pkg->buffer + len) = tb_crc(pkg->buffer, len);
382 
383 	res = tb_ring_tx(ctl->tx, &pkg->frame);
384 	if (res) /* ring is stopped */
385 		tb_ctl_pkg_free(pkg);
386 	return res;
387 }
388 
389 /*
390  * tb_ctl_handle_event() - acknowledge a plug event, invoke ctl->callback
391  */
tb_ctl_handle_event(struct tb_ctl * ctl,enum tb_cfg_pkg_type type,struct ctl_pkg * pkg,size_t size)392 static bool tb_ctl_handle_event(struct tb_ctl *ctl, enum tb_cfg_pkg_type type,
393 				struct ctl_pkg *pkg, size_t size)
394 {
395 	trace_tb_event(ctl->index, type, pkg->buffer, size);
396 	return ctl->callback(ctl->callback_data, type, pkg->buffer, size);
397 }
398 
tb_ctl_rx_submit(struct ctl_pkg * pkg)399 static void tb_ctl_rx_submit(struct ctl_pkg *pkg)
400 {
401 	tb_ring_rx(pkg->ctl->rx, &pkg->frame); /*
402 					     * We ignore failures during stop.
403 					     * All rx packets are referenced
404 					     * from ctl->rx_packets, so we do
405 					     * not loose them.
406 					     */
407 }
408 
tb_async_error(const struct ctl_pkg * pkg)409 static int tb_async_error(const struct ctl_pkg *pkg)
410 {
411 	const struct cfg_error_pkg *error = pkg->buffer;
412 
413 	if (pkg->frame.eof != TB_CFG_PKG_ERROR)
414 		return false;
415 
416 	switch (error->error) {
417 	case TB_CFG_ERROR_LINK_ERROR:
418 	case TB_CFG_ERROR_HEC_ERROR_DETECTED:
419 	case TB_CFG_ERROR_FLOW_CONTROL_ERROR:
420 	case TB_CFG_ERROR_DP_BW:
421 	case TB_CFG_ERROR_ROP_CMPLT:
422 	case TB_CFG_ERROR_POP_CMPLT:
423 	case TB_CFG_ERROR_PCIE_WAKE:
424 	case TB_CFG_ERROR_DP_CON_CHANGE:
425 	case TB_CFG_ERROR_DPTX_DISCOVERY:
426 	case TB_CFG_ERROR_LINK_RECOVERY:
427 	case TB_CFG_ERROR_ASYM_LINK:
428 		return true;
429 
430 	default:
431 		return false;
432 	}
433 }
434 
tb_ctl_rx_callback(struct tb_ring * ring,struct ring_frame * frame,bool canceled)435 static void tb_ctl_rx_callback(struct tb_ring *ring, struct ring_frame *frame,
436 			       bool canceled)
437 {
438 	struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
439 	struct tb_cfg_request *req;
440 	__be32 crc32;
441 
442 	if (canceled)
443 		return; /*
444 			 * ring is stopped, packet is referenced from
445 			 * ctl->rx_packets.
446 			 */
447 
448 	if (frame->size < 4 || frame->size % 4 != 0) {
449 		tb_ctl_err(pkg->ctl, "RX: invalid size %#x, dropping packet\n",
450 			   frame->size);
451 		goto rx;
452 	}
453 
454 	frame->size -= 4; /* remove checksum */
455 	crc32 = tb_crc(pkg->buffer, frame->size);
456 	be32_to_cpu_array(pkg->buffer, pkg->buffer, frame->size / 4);
457 
458 	switch (frame->eof) {
459 	case TB_CFG_PKG_READ:
460 	case TB_CFG_PKG_WRITE:
461 	case TB_CFG_PKG_ERROR:
462 	case TB_CFG_PKG_OVERRIDE:
463 	case TB_CFG_PKG_RESET:
464 		if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
465 			tb_ctl_err(pkg->ctl,
466 				   "RX: checksum mismatch, dropping packet\n");
467 			goto rx;
468 		}
469 		if (tb_async_error(pkg)) {
470 			tb_ctl_handle_event(pkg->ctl, frame->eof,
471 					    pkg, frame->size);
472 			goto rx;
473 		}
474 		break;
475 
476 	case TB_CFG_PKG_EVENT:
477 	case TB_CFG_PKG_XDOMAIN_RESP:
478 	case TB_CFG_PKG_XDOMAIN_REQ:
479 		if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
480 			tb_ctl_err(pkg->ctl,
481 				   "RX: checksum mismatch, dropping packet\n");
482 			goto rx;
483 		}
484 		fallthrough;
485 	case TB_CFG_PKG_ICM_EVENT:
486 		if (tb_ctl_handle_event(pkg->ctl, frame->eof, pkg, frame->size))
487 			goto rx;
488 		break;
489 
490 	default:
491 		break;
492 	}
493 
494 	/*
495 	 * The received packet will be processed only if there is an
496 	 * active request and that the packet is what is expected. This
497 	 * prevents packets such as replies coming after timeout has
498 	 * triggered from messing with the active requests.
499 	 */
500 	req = tb_cfg_request_find(pkg->ctl, pkg);
501 
502 	trace_tb_rx(pkg->ctl->index, frame->eof, pkg->buffer, frame->size, !req);
503 
504 	if (req) {
505 		if (req->copy(req, pkg))
506 			schedule_work(&req->work);
507 		tb_cfg_request_put(req);
508 	}
509 
510 rx:
511 	tb_ctl_rx_submit(pkg);
512 }
513 
tb_cfg_request_work(struct work_struct * work)514 static void tb_cfg_request_work(struct work_struct *work)
515 {
516 	struct tb_cfg_request *req = container_of(work, typeof(*req), work);
517 
518 	if (!test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
519 		req->callback(req->callback_data);
520 
521 	tb_cfg_request_dequeue(req);
522 	tb_cfg_request_put(req);
523 }
524 
525 /**
526  * tb_cfg_request() - Start control request not waiting for it to complete
527  * @ctl: Control channel to use
528  * @req: Request to start
529  * @callback: Callback called when the request is completed
530  * @callback_data: Data to be passed to @callback
531  *
532  * This queues @req on the given control channel without waiting for it
533  * to complete. When the request completes @callback is called.
534  */
tb_cfg_request(struct tb_ctl * ctl,struct tb_cfg_request * req,void (* callback)(void *),void * callback_data)535 int tb_cfg_request(struct tb_ctl *ctl, struct tb_cfg_request *req,
536 		   void (*callback)(void *), void *callback_data)
537 {
538 	int ret;
539 
540 	req->flags = 0;
541 	req->callback = callback;
542 	req->callback_data = callback_data;
543 	INIT_WORK(&req->work, tb_cfg_request_work);
544 	INIT_LIST_HEAD(&req->list);
545 
546 	tb_cfg_request_get(req);
547 	ret = tb_cfg_request_enqueue(ctl, req);
548 	if (ret)
549 		goto err_put;
550 
551 	ret = tb_ctl_tx(ctl, req->request, req->request_size,
552 			req->request_type);
553 	if (ret)
554 		goto err_dequeue;
555 
556 	if (!req->response)
557 		schedule_work(&req->work);
558 
559 	return 0;
560 
561 err_dequeue:
562 	tb_cfg_request_dequeue(req);
563 err_put:
564 	tb_cfg_request_put(req);
565 
566 	return ret;
567 }
568 
569 /**
570  * tb_cfg_request_cancel() - Cancel a control request
571  * @req: Request to cancel
572  * @err: Error to assign to the request
573  *
574  * This function can be used to cancel ongoing request. It will wait
575  * until the request is not active anymore.
576  */
tb_cfg_request_cancel(struct tb_cfg_request * req,int err)577 void tb_cfg_request_cancel(struct tb_cfg_request *req, int err)
578 {
579 	set_bit(TB_CFG_REQUEST_CANCELED, &req->flags);
580 	schedule_work(&req->work);
581 	wait_event(tb_cfg_request_cancel_queue, !tb_cfg_request_is_active(req));
582 	req->result.err = err;
583 }
584 
tb_cfg_request_complete(void * data)585 static void tb_cfg_request_complete(void *data)
586 {
587 	complete(data);
588 }
589 
590 /**
591  * tb_cfg_request_sync() - Start control request and wait until it completes
592  * @ctl: Control channel to use
593  * @req: Request to start
594  * @timeout_msec: Timeout how long to wait @req to complete
595  *
596  * Starts a control request and waits until it completes. If timeout
597  * triggers the request is canceled before function returns. Note the
598  * caller needs to make sure only one message for given switch is active
599  * at a time.
600  */
tb_cfg_request_sync(struct tb_ctl * ctl,struct tb_cfg_request * req,int timeout_msec)601 struct tb_cfg_result tb_cfg_request_sync(struct tb_ctl *ctl,
602 					 struct tb_cfg_request *req,
603 					 int timeout_msec)
604 {
605 	unsigned long timeout = msecs_to_jiffies(timeout_msec);
606 	struct tb_cfg_result res = { 0 };
607 	DECLARE_COMPLETION_ONSTACK(done);
608 	int ret;
609 
610 	ret = tb_cfg_request(ctl, req, tb_cfg_request_complete, &done);
611 	if (ret) {
612 		res.err = ret;
613 		return res;
614 	}
615 
616 	if (!wait_for_completion_timeout(&done, timeout))
617 		tb_cfg_request_cancel(req, -ETIMEDOUT);
618 
619 	flush_work(&req->work);
620 
621 	return req->result;
622 }
623 
624 /* public interface, alloc/start/stop/free */
625 
626 /**
627  * tb_ctl_alloc() - allocate a control channel
628  * @nhi: Pointer to NHI
629  * @index: Domain number
630  * @timeout_msec: Default timeout used with non-raw control messages
631  * @cb: Callback called for plug events
632  * @cb_data: Data passed to @cb
633  *
634  * cb will be invoked once for every hot plug event.
635  *
636  * Return: Returns a pointer on success or NULL on failure.
637  */
tb_ctl_alloc(struct tb_nhi * nhi,int index,int timeout_msec,event_cb cb,void * cb_data)638 struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, int index, int timeout_msec,
639 			    event_cb cb, void *cb_data)
640 {
641 	int i;
642 	struct tb_ctl *ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
643 	if (!ctl)
644 		return NULL;
645 
646 	ctl->nhi = nhi;
647 	ctl->index = index;
648 	ctl->timeout_msec = timeout_msec;
649 	ctl->callback = cb;
650 	ctl->callback_data = cb_data;
651 
652 	mutex_init(&ctl->request_queue_lock);
653 	INIT_LIST_HEAD(&ctl->request_queue);
654 	ctl->frame_pool = dma_pool_create("thunderbolt_ctl", &nhi->pdev->dev,
655 					 TB_FRAME_SIZE, 4, 0);
656 	if (!ctl->frame_pool)
657 		goto err;
658 
659 	ctl->tx = tb_ring_alloc_tx(nhi, 0, 10, RING_FLAG_NO_SUSPEND);
660 	if (!ctl->tx)
661 		goto err;
662 
663 	ctl->rx = tb_ring_alloc_rx(nhi, 0, 10, RING_FLAG_NO_SUSPEND, 0, 0xffff,
664 				   0xffff, NULL, NULL);
665 	if (!ctl->rx)
666 		goto err;
667 
668 	for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++) {
669 		ctl->rx_packets[i] = tb_ctl_pkg_alloc(ctl);
670 		if (!ctl->rx_packets[i])
671 			goto err;
672 		ctl->rx_packets[i]->frame.callback = tb_ctl_rx_callback;
673 	}
674 
675 	tb_ctl_dbg(ctl, "control channel created\n");
676 	return ctl;
677 err:
678 	tb_ctl_free(ctl);
679 	return NULL;
680 }
681 
682 /**
683  * tb_ctl_free() - free a control channel
684  * @ctl: Control channel to free
685  *
686  * Must be called after tb_ctl_stop.
687  *
688  * Must NOT be called from ctl->callback.
689  */
tb_ctl_free(struct tb_ctl * ctl)690 void tb_ctl_free(struct tb_ctl *ctl)
691 {
692 	int i;
693 
694 	if (!ctl)
695 		return;
696 
697 	if (ctl->rx)
698 		tb_ring_free(ctl->rx);
699 	if (ctl->tx)
700 		tb_ring_free(ctl->tx);
701 
702 	/* free RX packets */
703 	for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
704 		tb_ctl_pkg_free(ctl->rx_packets[i]);
705 
706 
707 	dma_pool_destroy(ctl->frame_pool);
708 	kfree(ctl);
709 }
710 
711 /**
712  * tb_ctl_start() - start/resume the control channel
713  * @ctl: Control channel to start
714  */
tb_ctl_start(struct tb_ctl * ctl)715 void tb_ctl_start(struct tb_ctl *ctl)
716 {
717 	int i;
718 	tb_ctl_dbg(ctl, "control channel starting...\n");
719 	tb_ring_start(ctl->tx); /* is used to ack hotplug packets, start first */
720 	tb_ring_start(ctl->rx);
721 	for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
722 		tb_ctl_rx_submit(ctl->rx_packets[i]);
723 
724 	ctl->running = true;
725 }
726 
727 /**
728  * tb_ctl_stop() - pause the control channel
729  * @ctl: Control channel to stop
730  *
731  * All invocations of ctl->callback will have finished after this method
732  * returns.
733  *
734  * Must NOT be called from ctl->callback.
735  */
tb_ctl_stop(struct tb_ctl * ctl)736 void tb_ctl_stop(struct tb_ctl *ctl)
737 {
738 	mutex_lock(&ctl->request_queue_lock);
739 	ctl->running = false;
740 	mutex_unlock(&ctl->request_queue_lock);
741 
742 	tb_ring_stop(ctl->rx);
743 	tb_ring_stop(ctl->tx);
744 
745 	if (!list_empty(&ctl->request_queue))
746 		tb_ctl_WARN(ctl, "dangling request in request_queue\n");
747 	INIT_LIST_HEAD(&ctl->request_queue);
748 	tb_ctl_dbg(ctl, "control channel stopped\n");
749 }
750 
751 /* public interface, commands */
752 
753 /**
754  * tb_cfg_ack_notification() - Ack notification
755  * @ctl: Control channel to use
756  * @route: Router that originated the event
757  * @error: Pointer to the notification package
758  *
759  * Call this as response for non-plug notification to ack it. Returns
760  * %0 on success or an error code on failure.
761  */
tb_cfg_ack_notification(struct tb_ctl * ctl,u64 route,const struct cfg_error_pkg * error)762 int tb_cfg_ack_notification(struct tb_ctl *ctl, u64 route,
763 			    const struct cfg_error_pkg *error)
764 {
765 	struct cfg_ack_pkg pkg = {
766 		.header = tb_cfg_make_header(route),
767 	};
768 	const char *name;
769 
770 	switch (error->error) {
771 	case TB_CFG_ERROR_LINK_ERROR:
772 		name = "link error";
773 		break;
774 	case TB_CFG_ERROR_HEC_ERROR_DETECTED:
775 		name = "HEC error";
776 		break;
777 	case TB_CFG_ERROR_FLOW_CONTROL_ERROR:
778 		name = "flow control error";
779 		break;
780 	case TB_CFG_ERROR_DP_BW:
781 		name = "DP_BW";
782 		break;
783 	case TB_CFG_ERROR_ROP_CMPLT:
784 		name = "router operation completion";
785 		break;
786 	case TB_CFG_ERROR_POP_CMPLT:
787 		name = "port operation completion";
788 		break;
789 	case TB_CFG_ERROR_PCIE_WAKE:
790 		name = "PCIe wake";
791 		break;
792 	case TB_CFG_ERROR_DP_CON_CHANGE:
793 		name = "DP connector change";
794 		break;
795 	case TB_CFG_ERROR_DPTX_DISCOVERY:
796 		name = "DPTX discovery";
797 		break;
798 	case TB_CFG_ERROR_LINK_RECOVERY:
799 		name = "link recovery";
800 		break;
801 	case TB_CFG_ERROR_ASYM_LINK:
802 		name = "asymmetric link";
803 		break;
804 	default:
805 		name = "unknown";
806 		break;
807 	}
808 
809 	tb_ctl_dbg(ctl, "acking %s (%#x) notification on %llx\n", name,
810 		   error->error, route);
811 
812 	return tb_ctl_tx(ctl, &pkg, sizeof(pkg), TB_CFG_PKG_NOTIFY_ACK);
813 }
814 
815 /**
816  * tb_cfg_ack_plug() - Ack hot plug/unplug event
817  * @ctl: Control channel to use
818  * @route: Router that originated the event
819  * @port: Port where the hot plug/unplug happened
820  * @unplug: Ack hot plug or unplug
821  *
822  * Call this as response for hot plug/unplug event to ack it.
823  * Returns %0 on success or an error code on failure.
824  */
tb_cfg_ack_plug(struct tb_ctl * ctl,u64 route,u32 port,bool unplug)825 int tb_cfg_ack_plug(struct tb_ctl *ctl, u64 route, u32 port, bool unplug)
826 {
827 	struct cfg_error_pkg pkg = {
828 		.header = tb_cfg_make_header(route),
829 		.port = port,
830 		.error = TB_CFG_ERROR_ACK_PLUG_EVENT,
831 		.pg = unplug ? TB_CFG_ERROR_PG_HOT_UNPLUG
832 			     : TB_CFG_ERROR_PG_HOT_PLUG,
833 	};
834 	tb_ctl_dbg(ctl, "acking hot %splug event on %llx:%u\n",
835 		   unplug ? "un" : "", route, port);
836 	return tb_ctl_tx(ctl, &pkg, sizeof(pkg), TB_CFG_PKG_ERROR);
837 }
838 
tb_cfg_match(const struct tb_cfg_request * req,const struct ctl_pkg * pkg)839 static bool tb_cfg_match(const struct tb_cfg_request *req,
840 			 const struct ctl_pkg *pkg)
841 {
842 	u64 route = tb_cfg_get_route(pkg->buffer) & ~BIT_ULL(63);
843 
844 	if (pkg->frame.eof == TB_CFG_PKG_ERROR)
845 		return true;
846 
847 	if (pkg->frame.eof != req->response_type)
848 		return false;
849 	if (route != tb_cfg_get_route(req->request))
850 		return false;
851 	if (pkg->frame.size != req->response_size)
852 		return false;
853 
854 	if (pkg->frame.eof == TB_CFG_PKG_READ ||
855 	    pkg->frame.eof == TB_CFG_PKG_WRITE) {
856 		const struct cfg_read_pkg *req_hdr = req->request;
857 		const struct cfg_read_pkg *res_hdr = pkg->buffer;
858 
859 		if (req_hdr->addr.seq != res_hdr->addr.seq)
860 			return false;
861 	}
862 
863 	return true;
864 }
865 
tb_cfg_copy(struct tb_cfg_request * req,const struct ctl_pkg * pkg)866 static bool tb_cfg_copy(struct tb_cfg_request *req, const struct ctl_pkg *pkg)
867 {
868 	struct tb_cfg_result res;
869 
870 	/* Now make sure it is in expected format */
871 	res = parse_header(pkg, req->response_size, req->response_type,
872 			   tb_cfg_get_route(req->request));
873 	if (!res.err)
874 		memcpy(req->response, pkg->buffer, req->response_size);
875 
876 	req->result = res;
877 
878 	/* Always complete when first response is received */
879 	return true;
880 }
881 
882 /**
883  * tb_cfg_reset() - send a reset packet and wait for a response
884  * @ctl: Control channel pointer
885  * @route: Router string for the router to send reset
886  *
887  * If the switch at route is incorrectly configured then we will not receive a
888  * reply (even though the switch will reset). The caller should check for
889  * -ETIMEDOUT and attempt to reconfigure the switch.
890  */
tb_cfg_reset(struct tb_ctl * ctl,u64 route)891 struct tb_cfg_result tb_cfg_reset(struct tb_ctl *ctl, u64 route)
892 {
893 	struct cfg_reset_pkg request = { .header = tb_cfg_make_header(route) };
894 	struct tb_cfg_result res = { 0 };
895 	struct tb_cfg_header reply;
896 	struct tb_cfg_request *req;
897 
898 	req = tb_cfg_request_alloc();
899 	if (!req) {
900 		res.err = -ENOMEM;
901 		return res;
902 	}
903 
904 	req->match = tb_cfg_match;
905 	req->copy = tb_cfg_copy;
906 	req->request = &request;
907 	req->request_size = sizeof(request);
908 	req->request_type = TB_CFG_PKG_RESET;
909 	req->response = &reply;
910 	req->response_size = sizeof(reply);
911 	req->response_type = TB_CFG_PKG_RESET;
912 
913 	res = tb_cfg_request_sync(ctl, req, ctl->timeout_msec);
914 
915 	tb_cfg_request_put(req);
916 
917 	return res;
918 }
919 
920 /**
921  * tb_cfg_read_raw() - read from config space into buffer
922  * @ctl: Pointer to the control channel
923  * @buffer: Buffer where the data is read
924  * @route: Route string of the router
925  * @port: Port number when reading from %TB_CFG_PORT, %0 otherwise
926  * @space: Config space selector
927  * @offset: Dword word offset of the register to start reading
928  * @length: Number of dwords to read
929  * @timeout_msec: Timeout in ms how long to wait for the response
930  *
931  * Reads from router config space without translating the possible error.
932  */
tb_cfg_read_raw(struct tb_ctl * ctl,void * buffer,u64 route,u32 port,enum tb_cfg_space space,u32 offset,u32 length,int timeout_msec)933 struct tb_cfg_result tb_cfg_read_raw(struct tb_ctl *ctl, void *buffer,
934 		u64 route, u32 port, enum tb_cfg_space space,
935 		u32 offset, u32 length, int timeout_msec)
936 {
937 	struct tb_cfg_result res = { 0 };
938 	struct cfg_read_pkg request = {
939 		.header = tb_cfg_make_header(route),
940 		.addr = {
941 			.port = port,
942 			.space = space,
943 			.offset = offset,
944 			.length = length,
945 		},
946 	};
947 	struct cfg_write_pkg reply;
948 	int retries = 0;
949 
950 	while (retries < TB_CTL_RETRIES) {
951 		struct tb_cfg_request *req;
952 
953 		req = tb_cfg_request_alloc();
954 		if (!req) {
955 			res.err = -ENOMEM;
956 			return res;
957 		}
958 
959 		request.addr.seq = retries++;
960 
961 		req->match = tb_cfg_match;
962 		req->copy = tb_cfg_copy;
963 		req->request = &request;
964 		req->request_size = sizeof(request);
965 		req->request_type = TB_CFG_PKG_READ;
966 		req->response = &reply;
967 		req->response_size = 12 + 4 * length;
968 		req->response_type = TB_CFG_PKG_READ;
969 
970 		res = tb_cfg_request_sync(ctl, req, timeout_msec);
971 
972 		tb_cfg_request_put(req);
973 
974 		if (res.err != -ETIMEDOUT)
975 			break;
976 
977 		/* Wait a bit (arbitrary time) until we send a retry */
978 		usleep_range(10, 100);
979 	}
980 
981 	if (res.err)
982 		return res;
983 
984 	res.response_port = reply.addr.port;
985 	res.err = check_config_address(reply.addr, space, offset, length);
986 	if (!res.err)
987 		memcpy(buffer, &reply.data, 4 * length);
988 	return res;
989 }
990 
991 /**
992  * tb_cfg_write_raw() - write from buffer into config space
993  * @ctl: Pointer to the control channel
994  * @buffer: Data to write
995  * @route: Route string of the router
996  * @port: Port number when writing to %TB_CFG_PORT, %0 otherwise
997  * @space: Config space selector
998  * @offset: Dword word offset of the register to start writing
999  * @length: Number of dwords to write
1000  * @timeout_msec: Timeout in ms how long to wait for the response
1001  *
1002  * Writes to router config space without translating the possible error.
1003  */
tb_cfg_write_raw(struct tb_ctl * ctl,const void * buffer,u64 route,u32 port,enum tb_cfg_space space,u32 offset,u32 length,int timeout_msec)1004 struct tb_cfg_result tb_cfg_write_raw(struct tb_ctl *ctl, const void *buffer,
1005 		u64 route, u32 port, enum tb_cfg_space space,
1006 		u32 offset, u32 length, int timeout_msec)
1007 {
1008 	struct tb_cfg_result res = { 0 };
1009 	struct cfg_write_pkg request = {
1010 		.header = tb_cfg_make_header(route),
1011 		.addr = {
1012 			.port = port,
1013 			.space = space,
1014 			.offset = offset,
1015 			.length = length,
1016 		},
1017 	};
1018 	struct cfg_read_pkg reply;
1019 	int retries = 0;
1020 
1021 	memcpy(&request.data, buffer, length * 4);
1022 
1023 	while (retries < TB_CTL_RETRIES) {
1024 		struct tb_cfg_request *req;
1025 
1026 		req = tb_cfg_request_alloc();
1027 		if (!req) {
1028 			res.err = -ENOMEM;
1029 			return res;
1030 		}
1031 
1032 		request.addr.seq = retries++;
1033 
1034 		req->match = tb_cfg_match;
1035 		req->copy = tb_cfg_copy;
1036 		req->request = &request;
1037 		req->request_size = 12 + 4 * length;
1038 		req->request_type = TB_CFG_PKG_WRITE;
1039 		req->response = &reply;
1040 		req->response_size = sizeof(reply);
1041 		req->response_type = TB_CFG_PKG_WRITE;
1042 
1043 		res = tb_cfg_request_sync(ctl, req, timeout_msec);
1044 
1045 		tb_cfg_request_put(req);
1046 
1047 		if (res.err != -ETIMEDOUT)
1048 			break;
1049 
1050 		/* Wait a bit (arbitrary time) until we send a retry */
1051 		usleep_range(10, 100);
1052 	}
1053 
1054 	if (res.err)
1055 		return res;
1056 
1057 	res.response_port = reply.addr.port;
1058 	res.err = check_config_address(reply.addr, space, offset, length);
1059 	return res;
1060 }
1061 
tb_cfg_get_error(struct tb_ctl * ctl,enum tb_cfg_space space,const struct tb_cfg_result * res)1062 static int tb_cfg_get_error(struct tb_ctl *ctl, enum tb_cfg_space space,
1063 			    const struct tb_cfg_result *res)
1064 {
1065 	/*
1066 	 * For unimplemented ports access to port config space may return
1067 	 * TB_CFG_ERROR_INVALID_CONFIG_SPACE (alternatively their type is
1068 	 * set to TB_TYPE_INACTIVE). In the former case return -ENODEV so
1069 	 * that the caller can mark the port as disabled.
1070 	 */
1071 	if (space == TB_CFG_PORT &&
1072 	    res->tb_error == TB_CFG_ERROR_INVALID_CONFIG_SPACE)
1073 		return -ENODEV;
1074 
1075 	tb_cfg_print_error(ctl, res);
1076 
1077 	if (res->tb_error == TB_CFG_ERROR_LOCK)
1078 		return -EACCES;
1079 	if (res->tb_error == TB_CFG_ERROR_PORT_NOT_CONNECTED)
1080 		return -ENOTCONN;
1081 
1082 	return -EIO;
1083 }
1084 
tb_cfg_read(struct tb_ctl * ctl,void * buffer,u64 route,u32 port,enum tb_cfg_space space,u32 offset,u32 length)1085 int tb_cfg_read(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
1086 		enum tb_cfg_space space, u32 offset, u32 length)
1087 {
1088 	struct tb_cfg_result res = tb_cfg_read_raw(ctl, buffer, route, port,
1089 			space, offset, length, ctl->timeout_msec);
1090 	switch (res.err) {
1091 	case 0:
1092 		/* Success */
1093 		break;
1094 
1095 	case 1:
1096 		/* Thunderbolt error, tb_error holds the actual number */
1097 		return tb_cfg_get_error(ctl, space, &res);
1098 
1099 	case -ETIMEDOUT:
1100 		tb_ctl_warn(ctl, "%llx: timeout reading config space %u from %#x\n",
1101 			    route, space, offset);
1102 		break;
1103 
1104 	default:
1105 		WARN(1, "tb_cfg_read: %d\n", res.err);
1106 		break;
1107 	}
1108 	return res.err;
1109 }
1110 
tb_cfg_write(struct tb_ctl * ctl,const void * buffer,u64 route,u32 port,enum tb_cfg_space space,u32 offset,u32 length)1111 int tb_cfg_write(struct tb_ctl *ctl, const void *buffer, u64 route, u32 port,
1112 		 enum tb_cfg_space space, u32 offset, u32 length)
1113 {
1114 	struct tb_cfg_result res = tb_cfg_write_raw(ctl, buffer, route, port,
1115 			space, offset, length, ctl->timeout_msec);
1116 	switch (res.err) {
1117 	case 0:
1118 		/* Success */
1119 		break;
1120 
1121 	case 1:
1122 		/* Thunderbolt error, tb_error holds the actual number */
1123 		return tb_cfg_get_error(ctl, space, &res);
1124 
1125 	case -ETIMEDOUT:
1126 		tb_ctl_warn(ctl, "%llx: timeout writing config space %u to %#x\n",
1127 			    route, space, offset);
1128 		break;
1129 
1130 	default:
1131 		WARN(1, "tb_cfg_write: %d\n", res.err);
1132 		break;
1133 	}
1134 	return res.err;
1135 }
1136 
1137 /**
1138  * tb_cfg_get_upstream_port() - get upstream port number of switch at route
1139  * @ctl: Pointer to the control channel
1140  * @route: Route string of the router
1141  *
1142  * Reads the first dword from the switches TB_CFG_SWITCH config area and
1143  * returns the port number from which the reply originated.
1144  *
1145  * Return: Returns the upstream port number on success or an error code on
1146  * failure.
1147  */
tb_cfg_get_upstream_port(struct tb_ctl * ctl,u64 route)1148 int tb_cfg_get_upstream_port(struct tb_ctl *ctl, u64 route)
1149 {
1150 	u32 dummy;
1151 	struct tb_cfg_result res = tb_cfg_read_raw(ctl, &dummy, route, 0,
1152 						   TB_CFG_SWITCH, 0, 1,
1153 						   ctl->timeout_msec);
1154 	if (res.err == 1)
1155 		return -EIO;
1156 	if (res.err)
1157 		return res.err;
1158 	return res.response_port;
1159 }
1160