xref: /openbmc/linux/drivers/thunderbolt/ctl.c (revision 235d0194)
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  */
36 struct 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 
68 static DECLARE_WAIT_QUEUE_HEAD(tb_cfg_request_cancel_queue);
69 /* Serializes access to request kref_get/put */
70 static 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  */
tb_cfg_request_alloc(void)78 struct 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  */
tb_cfg_request_get(struct tb_cfg_request * req)95 void 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 
tb_cfg_request_destroy(struct kref * kref)102 static 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  */
tb_cfg_request_put(struct tb_cfg_request * req)116 void 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 
tb_cfg_request_enqueue(struct tb_ctl * ctl,struct tb_cfg_request * req)123 static 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 
tb_cfg_request_dequeue(struct tb_cfg_request * req)141 static 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 
tb_cfg_request_is_active(struct tb_cfg_request * req)153 static bool tb_cfg_request_is_active(struct tb_cfg_request *req)
154 {
155 	return test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
156 }
157 
158 static struct tb_cfg_request *
tb_cfg_request_find(struct tb_ctl * ctl,struct ctl_pkg * pkg)159 tb_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 
check_header(const struct ctl_pkg * pkg,u32 len,enum tb_cfg_pkg_type type,u64 route)180 static 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 
check_config_address(struct tb_cfg_address addr,enum tb_cfg_space space,u32 offset,u32 length)208 static 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 
decode_error(const struct ctl_pkg * response)230 static 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 
parse_header(const struct ctl_pkg * pkg,u32 len,enum tb_cfg_pkg_type type,u64 route)248 static 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 
tb_cfg_print_error(struct tb_ctl * ctl,const struct tb_cfg_result * res)263 static 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 
tb_crc(const void * data,size_t len)305 static __be32 tb_crc(const void *data, size_t len)
306 {
307 	return cpu_to_be32(~__crc32c_le(~0, data, len));
308 }
309 
tb_ctl_pkg_free(struct ctl_pkg * pkg)310 static 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 
tb_ctl_pkg_alloc(struct tb_ctl * ctl)319 static 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 
tb_ctl_tx_callback(struct tb_ring * ring,struct ring_frame * frame,bool canceled)337 static 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  */
tb_ctl_tx(struct tb_ctl * ctl,const void * data,size_t len,enum tb_cfg_pkg_type type)351 static 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  */
tb_ctl_handle_event(struct tb_ctl * ctl,enum tb_cfg_pkg_type type,struct ctl_pkg * pkg,size_t size)384 static 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 
tb_ctl_rx_submit(struct ctl_pkg * pkg)390 static 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 
tb_async_error(const struct ctl_pkg * pkg)400 static 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 
tb_ctl_rx_callback(struct tb_ring * ring,struct ring_frame * frame,bool canceled)426 static 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 
498 rx:
499 	tb_ctl_rx_submit(pkg);
500 }
501 
tb_cfg_request_work(struct work_struct * work)502 static 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  */
tb_cfg_request(struct tb_ctl * ctl,struct tb_cfg_request * req,void (* callback)(void *),void * callback_data)523 int 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 
549 err_dequeue:
550 	tb_cfg_request_dequeue(req);
551 err_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  */
tb_cfg_request_cancel(struct tb_cfg_request * req,int err)565 void 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 
tb_cfg_request_complete(void * data)573 static 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  */
tb_cfg_request_sync(struct tb_ctl * ctl,struct tb_cfg_request * req,int timeout_msec)589 struct 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  */
tb_ctl_alloc(struct tb_nhi * nhi,int timeout_msec,event_cb cb,void * cb_data)625 struct 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;
662 err:
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  */
tb_ctl_free(struct tb_ctl * ctl)675 void 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  */
tb_ctl_start(struct tb_ctl * ctl)700 void 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  */
tb_ctl_stop(struct tb_ctl * ctl)721 void 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  */
tb_cfg_ack_notification(struct tb_ctl * ctl,u64 route,const struct cfg_error_pkg * error)747 int 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  */
tb_cfg_ack_plug(struct tb_ctl * ctl,u64 route,u32 port,bool unplug)810 int 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 
tb_cfg_match(const struct tb_cfg_request * req,const struct ctl_pkg * pkg)824 static 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 
tb_cfg_copy(struct tb_cfg_request * req,const struct ctl_pkg * pkg)851 static 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  */
tb_cfg_reset(struct tb_ctl * ctl,u64 route)876 struct 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  */
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)918 struct 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  */
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)989 struct 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 
tb_cfg_get_error(struct tb_ctl * ctl,enum tb_cfg_space space,const struct tb_cfg_result * res)1047 static 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 
tb_cfg_read(struct tb_ctl * ctl,void * buffer,u64 route,u32 port,enum tb_cfg_space space,u32 offset,u32 length)1070 int 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 
tb_cfg_write(struct tb_ctl * ctl,const void * buffer,u64 route,u32 port,enum tb_cfg_space space,u32 offset,u32 length)1096 int 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  */
tb_cfg_get_upstream_port(struct tb_ctl * ctl,u64 route)1133 int 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 }
1145