Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
/*
 * Thunderbolt Cactus Ridge driver - control channel and configuration commands
 *
 * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
 */

#include <linux/crc32.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/dmapool.h>
#include <linux/workqueue.h>
#include <linux/kfifo.h>

#include "ctl.h"


struct ctl_pkg {
	struct tb_ctl *ctl;
	void *buffer;
	struct ring_frame frame;
};

#define TB_CTL_RX_PKG_COUNT 10

/**
 * struct tb_cfg - thunderbolt control channel
 */
struct tb_ctl {
	struct tb_nhi *nhi;
	struct tb_ring *tx;
	struct tb_ring *rx;

	struct dma_pool *frame_pool;
	struct ctl_pkg *rx_packets[TB_CTL_RX_PKG_COUNT];
	DECLARE_KFIFO(response_fifo, struct ctl_pkg*, 16);
	struct completion response_ready;

	hotplug_cb callback;
	void *callback_data;
};


#define tb_ctl_WARN(ctl, format, arg...) \
	dev_WARN(&(ctl)->nhi->pdev->dev, format, ## arg)

#define tb_ctl_err(ctl, format, arg...) \
	dev_err(&(ctl)->nhi->pdev->dev, format, ## arg)

#define tb_ctl_warn(ctl, format, arg...) \
	dev_warn(&(ctl)->nhi->pdev->dev, format, ## arg)

#define tb_ctl_info(ctl, format, arg...) \
	dev_info(&(ctl)->nhi->pdev->dev, format, ## arg)


/* configuration packets definitions */

enum tb_cfg_pkg_type {
	TB_CFG_PKG_READ = 1,
	TB_CFG_PKG_WRITE = 2,
	TB_CFG_PKG_ERROR = 3,
	TB_CFG_PKG_NOTIFY_ACK = 4,
	TB_CFG_PKG_EVENT = 5,
	TB_CFG_PKG_XDOMAIN_REQ = 6,
	TB_CFG_PKG_XDOMAIN_RESP = 7,
	TB_CFG_PKG_OVERRIDE = 8,
	TB_CFG_PKG_RESET = 9,
	TB_CFG_PKG_PREPARE_TO_SLEEP = 0xd,
};

/* common header */
struct tb_cfg_header {
	u32 route_hi:22;
	u32 unknown:10; /* highest order bit is set on replies */
	u32 route_lo;
} __packed;

/* additional header for read/write packets */
struct tb_cfg_address {
	u32 offset:13; /* in dwords */
	u32 length:6; /* in dwords */
	u32 port:6;
	enum tb_cfg_space space:2;
	u32 seq:2; /* sequence number  */
	u32 zero:3;
} __packed;

/* TB_CFG_PKG_READ, response for TB_CFG_PKG_WRITE */
struct cfg_read_pkg {
	struct tb_cfg_header header;
	struct tb_cfg_address addr;
} __packed;

/* TB_CFG_PKG_WRITE, response for TB_CFG_PKG_READ */
struct cfg_write_pkg {
	struct tb_cfg_header header;
	struct tb_cfg_address addr;
	u32 data[64]; /* maximum size, tb_cfg_address.length has 6 bits */
} __packed;

/* TB_CFG_PKG_ERROR */
struct cfg_error_pkg {
	struct tb_cfg_header header;
	enum tb_cfg_error error:4;
	u32 zero1:4;
	u32 port:6;
	u32 zero2:2; /* Both should be zero, still they are different fields. */
	u32 zero3:16;
} __packed;

/* TB_CFG_PKG_EVENT */
struct cfg_event_pkg {
	struct tb_cfg_header header;
	u32 port:6;
	u32 zero:25;
	bool unplug:1;
} __packed;

/* TB_CFG_PKG_RESET */
struct cfg_reset_pkg {
	struct tb_cfg_header header;
} __packed;

/* TB_CFG_PKG_PREPARE_TO_SLEEP */
struct cfg_pts_pkg {
	struct tb_cfg_header header;
	u32 data;
} __packed;


/* utility functions */

static u64 get_route(struct tb_cfg_header header)
{
	return (u64) header.route_hi << 32 | header.route_lo;
}

static struct tb_cfg_header make_header(u64 route)
{
	struct tb_cfg_header header = {
		.route_hi = route >> 32,
		.route_lo = route,
	};
	/* check for overflow, route_hi is not 32 bits! */
	WARN_ON(get_route(header) != route);
	return header;
}

static int check_header(struct ctl_pkg *pkg, u32 len, enum tb_cfg_pkg_type type,
			u64 route)
{
	struct tb_cfg_header *header = pkg->buffer;

	/* check frame, TODO: frame flags */
	if (WARN(len != pkg->frame.size,
			"wrong framesize (expected %#x, got %#x)\n",
			len, pkg->frame.size))
		return -EIO;
	if (WARN(type != pkg->frame.eof, "wrong eof (expected %#x, got %#x)\n",
			type, pkg->frame.eof))
		return -EIO;
	if (WARN(pkg->frame.sof, "wrong sof (expected 0x0, got %#x)\n",
			pkg->frame.sof))
		return -EIO;

	/* check header */
	if (WARN(header->unknown != 1 << 9,
			"header->unknown is %#x\n", header->unknown))
		return -EIO;
	if (WARN(route != get_route(*header),
			"wrong route (expected %llx, got %llx)",
			route, get_route(*header)))
		return -EIO;
	return 0;
}

static int check_config_address(struct tb_cfg_address addr,
				enum tb_cfg_space space, u32 offset,
				u32 length)
{
	if (WARN(addr.zero, "addr.zero is %#x\n", addr.zero))
		return -EIO;
	if (WARN(space != addr.space, "wrong space (expected %x, got %x\n)",
			space, addr.space))
		return -EIO;
	if (WARN(offset != addr.offset, "wrong offset (expected %x, got %x\n)",
			offset, addr.offset))
		return -EIO;
	if (WARN(length != addr.length, "wrong space (expected %x, got %x\n)",
			length, addr.length))
		return -EIO;
	if (WARN(addr.seq, "addr.seq is %#x\n", addr.seq))
		return -EIO;
	/*
	 * We cannot check addr->port as it is set to the upstream port of the
	 * sender.
	 */
	return 0;
}

static struct tb_cfg_result decode_error(struct ctl_pkg *response)
{
	struct cfg_error_pkg *pkg = response->buffer;
	struct tb_cfg_result res = { 0 };
	res.response_route = get_route(pkg->header);
	res.response_port = 0;
	res.err = check_header(response, sizeof(*pkg), TB_CFG_PKG_ERROR,
			       get_route(pkg->header));
	if (res.err)
		return res;

	WARN(pkg->zero1, "pkg->zero1 is %#x\n", pkg->zero1);
	WARN(pkg->zero2, "pkg->zero1 is %#x\n", pkg->zero1);
	WARN(pkg->zero3, "pkg->zero1 is %#x\n", pkg->zero1);
	res.err = 1;
	res.tb_error = pkg->error;
	res.response_port = pkg->port;
	return res;

}

static struct tb_cfg_result parse_header(struct ctl_pkg *pkg, u32 len,
					 enum tb_cfg_pkg_type type, u64 route)
{
	struct tb_cfg_header *header = pkg->buffer;
	struct tb_cfg_result res = { 0 };

	if (pkg->frame.eof == TB_CFG_PKG_ERROR)
		return decode_error(pkg);

	res.response_port = 0; /* will be updated later for cfg_read/write */
	res.response_route = get_route(*header);
	res.err = check_header(pkg, len, type, route);
	return res;
}

static void tb_cfg_print_error(struct tb_ctl *ctl,
			       const struct tb_cfg_result *res)
{
	WARN_ON(res->err != 1);
	switch (res->tb_error) {
	case TB_CFG_ERROR_PORT_NOT_CONNECTED:
		/* Port is not connected. This can happen during surprise
		 * removal. Do not warn. */
		return;
	case TB_CFG_ERROR_INVALID_CONFIG_SPACE:
		/*
		 * Invalid cfg_space/offset/length combination in
		 * cfg_read/cfg_write.
		 */
		tb_ctl_WARN(ctl,
			"CFG_ERROR(%llx:%x): Invalid config space of offset\n",
			res->response_route, res->response_port);
		return;
	case TB_CFG_ERROR_NO_SUCH_PORT:
		/*
		 * - The route contains a non-existent port.
		 * - The route contains a non-PHY port (e.g. PCIe).
		 * - The port in cfg_read/cfg_write does not exist.
		 */
		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Invalid port\n",
			res->response_route, res->response_port);
		return;
	case TB_CFG_ERROR_LOOP:
		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Route contains a loop\n",
			res->response_route, res->response_port);
		return;
	default:
		/* 5,6,7,9 and 11 are also valid error codes */
		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Unknown error\n",
			res->response_route, res->response_port);
		return;
	}
}

static void cpu_to_be32_array(__be32 *dst, u32 *src, size_t len)
{
	int i;
	for (i = 0; i < len; i++)
		dst[i] = cpu_to_be32(src[i]);
}

static void be32_to_cpu_array(u32 *dst, __be32 *src, size_t len)
{
	int i;
	for (i = 0; i < len; i++)
		dst[i] = be32_to_cpu(src[i]);
}

static __be32 tb_crc(void *data, size_t len)
{
	return cpu_to_be32(~__crc32c_le(~0, data, len));
}

static void tb_ctl_pkg_free(struct ctl_pkg *pkg)
{
	if (pkg) {
		dma_pool_free(pkg->ctl->frame_pool,
			      pkg->buffer, pkg->frame.buffer_phy);
		kfree(pkg);
	}
}

static struct ctl_pkg *tb_ctl_pkg_alloc(struct tb_ctl *ctl)
{
	struct ctl_pkg *pkg = kzalloc(sizeof(*pkg), GFP_KERNEL);
	if (!pkg)
		return NULL;
	pkg->ctl = ctl;
	pkg->buffer = dma_pool_alloc(ctl->frame_pool, GFP_KERNEL,
				     &pkg->frame.buffer_phy);
	if (!pkg->buffer) {
		kfree(pkg);
		return NULL;
	}
	return pkg;
}


/* RX/TX handling */

static void tb_ctl_tx_callback(struct tb_ring *ring, struct ring_frame *frame,
			       bool canceled)
{
	struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
	tb_ctl_pkg_free(pkg);
}

/**
 * tb_cfg_tx() - transmit a packet on the control channel
 *
 * len must be a multiple of four.
 *
 * Return: Returns 0 on success or an error code on failure.
 */
static int tb_ctl_tx(struct tb_ctl *ctl, void *data, size_t len,
		     enum tb_cfg_pkg_type type)
{
	int res;
	struct ctl_pkg *pkg;
	if (len % 4 != 0) { /* required for le->be conversion */
		tb_ctl_WARN(ctl, "TX: invalid size: %zu\n", len);
		return -EINVAL;
	}
	if (len > TB_FRAME_SIZE - 4) { /* checksum is 4 bytes */
		tb_ctl_WARN(ctl, "TX: packet too large: %zu/%d\n",
			    len, TB_FRAME_SIZE - 4);
		return -EINVAL;
	}
	pkg = tb_ctl_pkg_alloc(ctl);
	if (!pkg)
		return -ENOMEM;
	pkg->frame.callback = tb_ctl_tx_callback;
	pkg->frame.size = len + 4;
	pkg->frame.sof = type;
	pkg->frame.eof = type;
	cpu_to_be32_array(pkg->buffer, data, len / 4);
	*(__be32 *) (pkg->buffer + len) = tb_crc(pkg->buffer, len);

	res = ring_tx(ctl->tx, &pkg->frame);
	if (res) /* ring is stopped */
		tb_ctl_pkg_free(pkg);
	return res;
}

/**
 * tb_ctl_handle_plug_event() - acknowledge a plug event, invoke ctl->callback
 */
static void tb_ctl_handle_plug_event(struct tb_ctl *ctl,
				     struct ctl_pkg *response)
{
	struct cfg_event_pkg *pkg = response->buffer;
	u64 route = get_route(pkg->header);

	if (check_header(response, sizeof(*pkg), TB_CFG_PKG_EVENT, route)) {
		tb_ctl_warn(ctl, "malformed TB_CFG_PKG_EVENT\n");
		return;
	}

	if (tb_cfg_error(ctl, route, pkg->port, TB_CFG_ERROR_ACK_PLUG_EVENT))
		tb_ctl_warn(ctl, "could not ack plug event on %llx:%x\n",
			    route, pkg->port);
	WARN(pkg->zero, "pkg->zero is %#x\n", pkg->zero);
	ctl->callback(ctl->callback_data, route, pkg->port, pkg->unplug);
}

static void tb_ctl_rx_submit(struct ctl_pkg *pkg)
{
	ring_rx(pkg->ctl->rx, &pkg->frame); /*
					     * We ignore failures during stop.
					     * All rx packets are referenced
					     * from ctl->rx_packets, so we do
					     * not loose them.
					     */
}

static void tb_ctl_rx_callback(struct tb_ring *ring, struct ring_frame *frame,
			       bool canceled)
{
	struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);

	if (canceled)
		return; /*
			 * ring is stopped, packet is referenced from
			 * ctl->rx_packets.
			 */

	if (frame->size < 4 || frame->size % 4 != 0) {
		tb_ctl_err(pkg->ctl, "RX: invalid size %#x, dropping packet\n",
			   frame->size);
		goto rx;
	}

	frame->size -= 4; /* remove checksum */
	if (*(__be32 *) (pkg->buffer + frame->size)
			!= tb_crc(pkg->buffer, frame->size)) {
		tb_ctl_err(pkg->ctl,
			   "RX: checksum mismatch, dropping packet\n");
		goto rx;
	}
	be32_to_cpu_array(pkg->buffer, pkg->buffer, frame->size / 4);

	if (frame->eof == TB_CFG_PKG_EVENT) {
		tb_ctl_handle_plug_event(pkg->ctl, pkg);
		goto rx;
	}
	if (!kfifo_put(&pkg->ctl->response_fifo, pkg)) {
		tb_ctl_err(pkg->ctl, "RX: fifo is full\n");
		goto rx;
	}
	complete(&pkg->ctl->response_ready);
	return;
rx:
	tb_ctl_rx_submit(pkg);
}

/**
 * tb_ctl_rx() - receive a packet from the control channel
 */
static struct tb_cfg_result tb_ctl_rx(struct tb_ctl *ctl, void *buffer,
				      size_t length, int timeout_msec,
				      u64 route, enum tb_cfg_pkg_type type)
{
	struct tb_cfg_result res;
	struct ctl_pkg *pkg;

	if (!wait_for_completion_timeout(&ctl->response_ready,
					 msecs_to_jiffies(timeout_msec))) {
		tb_ctl_WARN(ctl, "RX: timeout\n");
		return (struct tb_cfg_result) { .err = -ETIMEDOUT };
	}
	if (!kfifo_get(&ctl->response_fifo, &pkg)) {
		tb_ctl_WARN(ctl, "empty kfifo\n");
		return (struct tb_cfg_result) { .err = -EIO };
	}

	res = parse_header(pkg, length, type, route);
	if (!res.err)
		memcpy(buffer, pkg->buffer, length);
	tb_ctl_rx_submit(pkg);
	return res;
}


/* public interface, alloc/start/stop/free */

/**
 * tb_ctl_alloc() - allocate a control channel
 *
 * cb will be invoked once for every hot plug event.
 *
 * Return: Returns a pointer on success or NULL on failure.
 */
struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, hotplug_cb cb, void *cb_data)
{
	int i;
	struct tb_ctl *ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
	if (!ctl)
		return NULL;
	ctl->nhi = nhi;
	ctl->callback = cb;
	ctl->callback_data = cb_data;

	init_completion(&ctl->response_ready);
	INIT_KFIFO(ctl->response_fifo);
	ctl->frame_pool = dma_pool_create("thunderbolt_ctl", &nhi->pdev->dev,
					 TB_FRAME_SIZE, 4, 0);
	if (!ctl->frame_pool)
		goto err;

	ctl->tx = ring_alloc_tx(nhi, 0, 10);
	if (!ctl->tx)
		goto err;

	ctl->rx = ring_alloc_rx(nhi, 0, 10);
	if (!ctl->rx)
		goto err;

	for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++) {
		ctl->rx_packets[i] = tb_ctl_pkg_alloc(ctl);
		if (!ctl->rx_packets[i])
			goto err;
		ctl->rx_packets[i]->frame.callback = tb_ctl_rx_callback;
	}

	tb_ctl_info(ctl, "control channel created\n");
	return ctl;
err:
	tb_ctl_free(ctl);
	return NULL;
}

/**
 * tb_ctl_free() - free a control channel
 *
 * Must be called after tb_ctl_stop.
 *
 * Must NOT be called from ctl->callback.
 */
void tb_ctl_free(struct tb_ctl *ctl)
{
	int i;
	if (ctl->rx)
		ring_free(ctl->rx);
	if (ctl->tx)
		ring_free(ctl->tx);

	/* free RX packets */
	for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
		tb_ctl_pkg_free(ctl->rx_packets[i]);


	if (ctl->frame_pool)
		dma_pool_destroy(ctl->frame_pool);
	kfree(ctl);
}

/**
 * tb_cfg_start() - start/resume the control channel
 */
void tb_ctl_start(struct tb_ctl *ctl)
{
	int i;
	tb_ctl_info(ctl, "control channel starting...\n");
	ring_start(ctl->tx); /* is used to ack hotplug packets, start first */
	ring_start(ctl->rx);
	for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
		tb_ctl_rx_submit(ctl->rx_packets[i]);
}

/**
 * control() - pause the control channel
 *
 * All invocations of ctl->callback will have finished after this method
 * returns.
 *
 * Must NOT be called from ctl->callback.
 */
void tb_ctl_stop(struct tb_ctl *ctl)
{
	ring_stop(ctl->rx);
	ring_stop(ctl->tx);

	if (!kfifo_is_empty(&ctl->response_fifo))
		tb_ctl_WARN(ctl, "dangling response in response_fifo\n");
	kfifo_reset(&ctl->response_fifo);
	tb_ctl_info(ctl, "control channel stopped\n");
}

/* public interface, commands */

/**
 * tb_cfg_error() - send error packet
 *
 * Return: Returns 0 on success or an error code on failure.
 */
int tb_cfg_error(struct tb_ctl *ctl, u64 route, u32 port,
		 enum tb_cfg_error error)
{
	struct cfg_error_pkg pkg = {
		.header = make_header(route),
		.port = port,
		.error = error,
	};
	tb_ctl_info(ctl, "resetting error on %llx:%x.\n", route, port);
	return tb_ctl_tx(ctl, &pkg, sizeof(pkg), TB_CFG_PKG_ERROR);
}

/**
 * tb_cfg_reset() - send a reset packet and wait for a response
 *
 * If the switch at route is incorrectly configured then we will not receive a
 * reply (even though the switch will reset). The caller should check for
 * -ETIMEDOUT and attempt to reconfigure the switch.
 */
struct tb_cfg_result tb_cfg_reset(struct tb_ctl *ctl, u64 route,
				  int timeout_msec)
{
	int err;
	struct cfg_reset_pkg request = { .header = make_header(route) };
	struct tb_cfg_header reply;

	err = tb_ctl_tx(ctl, &request, sizeof(request), TB_CFG_PKG_RESET);
	if (err)
		return (struct tb_cfg_result) { .err = err };

	return tb_ctl_rx(ctl, &reply, sizeof(reply), timeout_msec, route,
			 TB_CFG_PKG_RESET);
}

/**
 * tb_cfg_read() - read from config space into buffer
 *
 * Offset and length are in dwords.
 */
struct tb_cfg_result 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)
{
	struct tb_cfg_result res = { 0 };
	struct cfg_read_pkg request = {
		.header = make_header(route),
		.addr = {
			.port = port,
			.space = space,
			.offset = offset,
			.length = length,
		},
	};
	struct cfg_write_pkg reply;

	res.err = tb_ctl_tx(ctl, &request, sizeof(request), TB_CFG_PKG_READ);
	if (res.err)
		return res;

	res = tb_ctl_rx(ctl, &reply, 12 + 4 * length, timeout_msec, route,
			TB_CFG_PKG_READ);
	if (res.err)
		return res;

	res.response_port = reply.addr.port;
	res.err = check_config_address(reply.addr, space, offset, length);
	if (!res.err)
		memcpy(buffer, &reply.data, 4 * length);
	return res;
}

/**
 * tb_cfg_write() - write from buffer into config space
 *
 * Offset and length are in dwords.
 */
struct tb_cfg_result tb_cfg_write_raw(struct tb_ctl *ctl, void *buffer,
		u64 route, u32 port, enum tb_cfg_space space,
		u32 offset, u32 length, int timeout_msec)
{
	struct tb_cfg_result res = { 0 };
	struct cfg_write_pkg request = {
		.header = make_header(route),
		.addr = {
			.port = port,
			.space = space,
			.offset = offset,
			.length = length,
		},
	};
	struct cfg_read_pkg reply;

	memcpy(&request.data, buffer, length * 4);

	res.err = tb_ctl_tx(ctl, &request, 12 + 4 * length, TB_CFG_PKG_WRITE);
	if (res.err)
		return res;

	res = tb_ctl_rx(ctl, &reply, sizeof(reply), timeout_msec, route,
			TB_CFG_PKG_WRITE);
	if (res.err)
		return res;

	res.response_port = reply.addr.port;
	res.err = check_config_address(reply.addr, space, offset, length);
	return res;
}

int tb_cfg_read(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
		enum tb_cfg_space space, u32 offset, u32 length)
{
	struct tb_cfg_result res = tb_cfg_read_raw(ctl, buffer, route, port,
			space, offset, length, TB_CFG_DEFAULT_TIMEOUT);
	if (res.err == 1) {
		tb_cfg_print_error(ctl, &res);
		return -EIO;
	}
	WARN(res.err, "tb_cfg_read: %d\n", res.err);
	return res.err;
}

int tb_cfg_write(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
		 enum tb_cfg_space space, u32 offset, u32 length)
{
	struct tb_cfg_result res = tb_cfg_write_raw(ctl, buffer, route, port,
			space, offset, length, TB_CFG_DEFAULT_TIMEOUT);
	if (res.err == 1) {
		tb_cfg_print_error(ctl, &res);
		return -EIO;
	}
	WARN(res.err, "tb_cfg_write: %d\n", res.err);
	return res.err;
}

/**
 * tb_cfg_get_upstream_port() - get upstream port number of switch at route
 *
 * Reads the first dword from the switches TB_CFG_SWITCH config area and
 * returns the port number from which the reply originated.
 *
 * Return: Returns the upstream port number on success or an error code on
 * failure.
 */
int tb_cfg_get_upstream_port(struct tb_ctl *ctl, u64 route)
{
	u32 dummy;
	struct tb_cfg_result res = tb_cfg_read_raw(ctl, &dummy, route, 0,
						   TB_CFG_SWITCH, 0, 1,
						   TB_CFG_DEFAULT_TIMEOUT);
	if (res.err == 1)
		return -EIO;
	if (res.err)
		return res.err;
	return res.response_port;
}