xref: /linux/drivers/thunderbolt/debugfs.c (revision 2eff01ee2881becc9daaa0d53477ec202136b1f4)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Debugfs interface
4  *
5  * Copyright (C) 2020, Intel Corporation
6  * Authors: Gil Fine <gil.fine@intel.com>
7  *	    Mika Westerberg <mika.westerberg@linux.intel.com>
8  */
9 
10 #include <linux/array_size.h>
11 #include <linux/bitfield.h>
12 #include <linux/debugfs.h>
13 #include <linux/delay.h>
14 #include <linux/pm_runtime.h>
15 #include <linux/uaccess.h>
16 
17 #include "tb.h"
18 #include "sb_regs.h"
19 
20 #define PORT_CAP_V1_PCIE_LEN	1
21 #define PORT_CAP_V2_PCIE_LEN	2
22 #define PORT_CAP_POWER_LEN	2
23 #define PORT_CAP_LANE_LEN	3
24 #define PORT_CAP_USB3_LEN	5
25 #define PORT_CAP_DP_V1_LEN	9
26 #define PORT_CAP_DP_V2_LEN	14
27 #define PORT_CAP_TMU_V1_LEN	8
28 #define PORT_CAP_TMU_V2_LEN	10
29 #define PORT_CAP_BASIC_LEN	9
30 #define PORT_CAP_USB4_LEN	20
31 
32 #define SWITCH_CAP_TMU_LEN	26
33 #define SWITCH_CAP_BASIC_LEN	27
34 
35 #define PATH_LEN		2
36 
37 #define COUNTER_SET_LEN		3
38 
39 /*
40  * USB4 spec doesn't specify dwell range, the range of 100 ms to 500 ms
41  * probed to give good results.
42  */
43 #define MIN_DWELL_TIME		100 /* ms */
44 #define MAX_DWELL_TIME		500 /* ms */
45 #define DWELL_SAMPLE_INTERVAL	10
46 
47 enum usb4_margin_cap_voltage_indp {
48 	USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_MIN,
49 	USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_HL,
50 	USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_BOTH,
51 	USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_4_MIN,
52 	USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_4_BOTH,
53 	USB4_MARGIN_CAP_VOLTAGE_INDP_UNKNOWN,
54 };
55 
56 enum usb4_margin_cap_time_indp {
57 	USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_MIN,
58 	USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_LR,
59 	USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_BOTH,
60 	USB4_MARGIN_CAP_TIME_INDP_GEN_4_MIN,
61 	USB4_MARGIN_CAP_TIME_INDP_GEN_4_BOTH,
62 	USB4_MARGIN_CAP_TIME_INDP_UNKNOWN,
63 };
64 
65 /* Sideband registers and their sizes as defined in the USB4 spec */
66 struct sb_reg {
67 	unsigned int reg;
68 	unsigned int size;
69 };
70 
71 #define SB_MAX_SIZE		64
72 
73 /* Sideband registers for router */
74 static const struct sb_reg port_sb_regs[] = {
75 	{ USB4_SB_VENDOR_ID, 4 },
76 	{ USB4_SB_PRODUCT_ID, 4 },
77 	{ USB4_SB_DEBUG_CONF, 4 },
78 	{ USB4_SB_DEBUG, 54 },
79 	{ USB4_SB_LRD_TUNING, 4 },
80 	{ USB4_SB_OPCODE, 4 },
81 	{ USB4_SB_METADATA, 4 },
82 	{ USB4_SB_LINK_CONF, 3 },
83 	{ USB4_SB_GEN23_TXFFE, 4 },
84 	{ USB4_SB_GEN4_TXFFE, 4 },
85 	{ USB4_SB_VERSION, 4 },
86 	{ USB4_SB_DATA, 64 },
87 };
88 
89 /* Sideband registers for retimer */
90 static const struct sb_reg retimer_sb_regs[] = {
91 	{ USB4_SB_VENDOR_ID, 4 },
92 	{ USB4_SB_PRODUCT_ID, 4 },
93 	{ USB4_SB_FW_VERSION, 4 },
94 	{ USB4_SB_LRD_TUNING, 4 },
95 	{ USB4_SB_OPCODE, 4 },
96 	{ USB4_SB_METADATA, 4 },
97 	{ USB4_SB_GEN23_TXFFE, 4 },
98 	{ USB4_SB_GEN4_TXFFE, 4 },
99 	{ USB4_SB_VERSION, 4 },
100 	{ USB4_SB_DATA, 64 },
101 };
102 
103 #define DEBUGFS_ATTR(__space, __write)					\
104 static int __space ## _open(struct inode *inode, struct file *file)	\
105 {									\
106 	return single_open(file, __space ## _show, inode->i_private);	\
107 }									\
108 									\
109 static const struct file_operations __space ## _fops = {		\
110 	.owner = THIS_MODULE,						\
111 	.open = __space ## _open,					\
112 	.release = single_release,					\
113 	.read  = seq_read,						\
114 	.write = __write,						\
115 	.llseek = seq_lseek,						\
116 }
117 
118 #define DEBUGFS_ATTR_RO(__space)					\
119 	DEBUGFS_ATTR(__space, NULL)
120 
121 #define DEBUGFS_ATTR_RW(__space)					\
122 	DEBUGFS_ATTR(__space, __space ## _write)
123 
124 static struct dentry *tb_debugfs_root;
125 
126 static void *validate_and_copy_from_user(const void __user *user_buf,
127 					 size_t *count)
128 {
129 	size_t nbytes;
130 	void *buf;
131 
132 	if (!*count)
133 		return ERR_PTR(-EINVAL);
134 
135 	if (!access_ok(user_buf, *count))
136 		return ERR_PTR(-EFAULT);
137 
138 	buf = (void *)get_zeroed_page(GFP_KERNEL);
139 	if (!buf)
140 		return ERR_PTR(-ENOMEM);
141 
142 	nbytes = min_t(size_t, *count, PAGE_SIZE);
143 	if (copy_from_user(buf, user_buf, nbytes)) {
144 		free_page((unsigned long)buf);
145 		return ERR_PTR(-EFAULT);
146 	}
147 
148 	*count = nbytes;
149 	return buf;
150 }
151 
152 static bool parse_line(char **line, u32 *offs, u32 *val, int short_fmt_len,
153 		       int long_fmt_len)
154 {
155 	char *token;
156 	u32 v[5];
157 	int ret;
158 
159 	token = strsep(line, "\n");
160 	if (!token)
161 		return false;
162 
163 	/*
164 	 * For Adapter/Router configuration space:
165 	 * Short format is: offset value\n
166 	 *		    v[0]   v[1]
167 	 * Long format as produced from the read side:
168 	 * offset relative_offset cap_id vs_cap_id value\n
169 	 * v[0]   v[1]            v[2]   v[3]      v[4]
170 	 *
171 	 * For Counter configuration space:
172 	 * Short format is: offset\n
173 	 *		    v[0]
174 	 * Long format as produced from the read side:
175 	 * offset relative_offset counter_id value\n
176 	 * v[0]   v[1]            v[2]       v[3]
177 	 */
178 	ret = sscanf(token, "%i %i %i %i %i", &v[0], &v[1], &v[2], &v[3], &v[4]);
179 	/* In case of Counters, clear counter, "val" content is NA */
180 	if (ret == short_fmt_len) {
181 		*offs = v[0];
182 		*val = v[short_fmt_len - 1];
183 		return true;
184 	} else if (ret == long_fmt_len) {
185 		*offs = v[0];
186 		*val = v[long_fmt_len - 1];
187 		return true;
188 	}
189 
190 	return false;
191 }
192 
193 #if IS_ENABLED(CONFIG_USB4_DEBUGFS_WRITE)
194 static ssize_t regs_write(struct tb_switch *sw, struct tb_port *port,
195 			  const char __user *user_buf, size_t count,
196 			  loff_t *ppos)
197 {
198 	struct tb *tb = sw->tb;
199 	char *line, *buf;
200 	u32 val, offset;
201 	int ret = 0;
202 
203 	buf = validate_and_copy_from_user(user_buf, &count);
204 	if (IS_ERR(buf))
205 		return PTR_ERR(buf);
206 
207 	pm_runtime_get_sync(&sw->dev);
208 
209 	if (mutex_lock_interruptible(&tb->lock)) {
210 		ret = -ERESTARTSYS;
211 		goto out;
212 	}
213 
214 	/* User did hardware changes behind the driver's back */
215 	add_taint(TAINT_USER, LOCKDEP_STILL_OK);
216 
217 	line = buf;
218 	while (parse_line(&line, &offset, &val, 2, 5)) {
219 		if (port)
220 			ret = tb_port_write(port, &val, TB_CFG_PORT, offset, 1);
221 		else
222 			ret = tb_sw_write(sw, &val, TB_CFG_SWITCH, offset, 1);
223 		if (ret)
224 			break;
225 	}
226 
227 	mutex_unlock(&tb->lock);
228 
229 out:
230 	pm_runtime_mark_last_busy(&sw->dev);
231 	pm_runtime_put_autosuspend(&sw->dev);
232 	free_page((unsigned long)buf);
233 
234 	return ret < 0 ? ret : count;
235 }
236 
237 static ssize_t port_regs_write(struct file *file, const char __user *user_buf,
238 			       size_t count, loff_t *ppos)
239 {
240 	struct seq_file *s = file->private_data;
241 	struct tb_port *port = s->private;
242 
243 	return regs_write(port->sw, port, user_buf, count, ppos);
244 }
245 
246 static ssize_t switch_regs_write(struct file *file, const char __user *user_buf,
247 				 size_t count, loff_t *ppos)
248 {
249 	struct seq_file *s = file->private_data;
250 	struct tb_switch *sw = s->private;
251 
252 	return regs_write(sw, NULL, user_buf, count, ppos);
253 }
254 
255 static bool parse_sb_line(char **line, u8 *reg, u8 *data, size_t data_size,
256 			  size_t *bytes_read)
257 {
258 	char *field, *token;
259 	int i;
260 
261 	token = strsep(line, "\n");
262 	if (!token)
263 		return false;
264 
265 	/* Parse the register first */
266 	field = strsep(&token, " ");
267 	if (!field)
268 		return false;
269 	if (kstrtou8(field, 0, reg))
270 		return false;
271 
272 	/* Then the values for the register, up to data_size */
273 	for (i = 0; i < data_size; i++) {
274 		field = strsep(&token, " ");
275 		if (!field)
276 			break;
277 		if (kstrtou8(field, 0, &data[i]))
278 			return false;
279 	}
280 
281 	*bytes_read = i;
282 	return true;
283 }
284 
285 static ssize_t sb_regs_write(struct tb_port *port, const struct sb_reg *sb_regs,
286 			     size_t size, enum usb4_sb_target target, u8 index,
287 			     char *buf, size_t count, loff_t *ppos)
288 {
289 	u8 reg, data[SB_MAX_SIZE];
290 	size_t bytes_read;
291 	char *line = buf;
292 
293 	/* User did hardware changes behind the driver's back */
294 	add_taint(TAINT_USER, LOCKDEP_STILL_OK);
295 
296 	/*
297 	 * For sideband registers we accept:
298 	 * reg b0 b1 b2...\n
299 	 *
300 	 * Here "reg" is the byte offset of the sideband register and "b0"..
301 	 * are the byte values. There can be less byte values than the register
302 	 * size. The leftovers will not be overwritten.
303 	 */
304 	while (parse_sb_line(&line, &reg, data, ARRAY_SIZE(data), &bytes_read)) {
305 		const struct sb_reg *sb_reg;
306 		int ret;
307 
308 		/* At least one byte must be passed */
309 		if (bytes_read < 1)
310 			return -EINVAL;
311 
312 		/* Find the register */
313 		sb_reg = NULL;
314 		for (int i = 0; i < size; i++) {
315 			if (sb_regs[i].reg == reg) {
316 				sb_reg = &sb_regs[i];
317 				break;
318 			}
319 		}
320 
321 		if (!sb_reg)
322 			return -EINVAL;
323 
324 		if (bytes_read > sb_regs->size)
325 			return -E2BIG;
326 
327 		ret = usb4_port_sb_write(port, target, index, sb_reg->reg, data,
328 					 bytes_read);
329 		if (ret)
330 			return ret;
331 	}
332 
333 	return 0;
334 }
335 
336 static ssize_t port_sb_regs_write(struct file *file, const char __user *user_buf,
337 				  size_t count, loff_t *ppos)
338 {
339 	struct seq_file *s = file->private_data;
340 	struct tb_port *port = s->private;
341 	struct tb_switch *sw = port->sw;
342 	struct tb *tb = sw->tb;
343 	char *buf;
344 	int ret;
345 
346 	buf = validate_and_copy_from_user(user_buf, &count);
347 	if (IS_ERR(buf))
348 		return PTR_ERR(buf);
349 
350 	pm_runtime_get_sync(&sw->dev);
351 
352 	if (mutex_lock_interruptible(&tb->lock)) {
353 		ret = -ERESTARTSYS;
354 		goto out;
355 	}
356 
357 	ret = sb_regs_write(port, port_sb_regs, ARRAY_SIZE(port_sb_regs),
358 			    USB4_SB_TARGET_ROUTER, 0, buf, count, ppos);
359 
360 	mutex_unlock(&tb->lock);
361 out:
362 	pm_runtime_mark_last_busy(&sw->dev);
363 	pm_runtime_put_autosuspend(&sw->dev);
364 	free_page((unsigned long)buf);
365 
366 	return ret < 0 ? ret : count;
367 }
368 
369 static ssize_t retimer_sb_regs_write(struct file *file,
370 				     const char __user *user_buf,
371 				     size_t count, loff_t *ppos)
372 {
373 	struct seq_file *s = file->private_data;
374 	struct tb_retimer *rt = s->private;
375 	struct tb *tb = rt->tb;
376 	char *buf;
377 	int ret;
378 
379 	buf = validate_and_copy_from_user(user_buf, &count);
380 	if (IS_ERR(buf))
381 		return PTR_ERR(buf);
382 
383 	pm_runtime_get_sync(&rt->dev);
384 
385 	if (mutex_lock_interruptible(&tb->lock)) {
386 		ret = -ERESTARTSYS;
387 		goto out;
388 	}
389 
390 	ret = sb_regs_write(rt->port, retimer_sb_regs, ARRAY_SIZE(retimer_sb_regs),
391 			    USB4_SB_TARGET_RETIMER, rt->index, buf, count, ppos);
392 
393 	mutex_unlock(&tb->lock);
394 out:
395 	pm_runtime_mark_last_busy(&rt->dev);
396 	pm_runtime_put_autosuspend(&rt->dev);
397 	free_page((unsigned long)buf);
398 
399 	return ret < 0 ? ret : count;
400 }
401 #define DEBUGFS_MODE		0600
402 #else
403 #define port_regs_write		NULL
404 #define switch_regs_write	NULL
405 #define port_sb_regs_write	NULL
406 #define retimer_sb_regs_write	NULL
407 #define DEBUGFS_MODE		0400
408 #endif
409 
410 #if IS_ENABLED(CONFIG_USB4_DEBUGFS_MARGINING)
411 /**
412  * struct tb_margining - Lane margining support
413  * @port: USB4 port through which the margining operations are run
414  * @target: Sideband target
415  * @index: Retimer index if taget is %USB4_SB_TARGET_RETIMER
416  * @dev: Pointer to the device that is the target (USB4 port or retimer)
417  * @gen: Link generation
418  * @asym_rx: %true% if @port supports asymmetric link with 3 Rx
419  * @caps: Port lane margining capabilities
420  * @results: Last lane margining results
421  * @lanes: %0, %1 or %7 (all)
422  * @min_ber_level: Minimum supported BER level contour value
423  * @max_ber_level: Maximum supported BER level contour value
424  * @ber_level: Current BER level contour value
425  * @voltage_steps: Number of mandatory voltage steps
426  * @max_voltage_offset: Maximum mandatory voltage offset (in mV)
427  * @voltage_steps_optional_range: Number of voltage steps for optional range
428  * @max_voltage_offset_optional_range: Maximum voltage offset for the optional
429  *					range (in mV).
430  * @time_steps: Number of time margin steps
431  * @max_time_offset: Maximum time margin offset (in mUI)
432  * @voltage_time_offset: Offset for voltage / time for software margining
433  * @dwell_time: Dwell time for software margining (in ms)
434  * @error_counter: Error counter operation for software margining
435  * @optional_voltage_offset_range: Enable optional extended voltage range
436  * @software: %true if software margining is used instead of hardware
437  * @time: %true if time margining is used instead of voltage
438  * @right_high: %false if left/low margin test is performed, %true if
439  *		right/high
440  * @upper_eye: %false if the lower PAM3 eye is used, %true if the upper
441  *	       eye is used
442  */
443 struct tb_margining {
444 	struct tb_port *port;
445 	enum usb4_sb_target target;
446 	u8 index;
447 	struct device *dev;
448 	unsigned int gen;
449 	bool asym_rx;
450 	u32 caps[3];
451 	u32 results[3];
452 	enum usb4_margining_lane lanes;
453 	unsigned int min_ber_level;
454 	unsigned int max_ber_level;
455 	unsigned int ber_level;
456 	unsigned int voltage_steps;
457 	unsigned int max_voltage_offset;
458 	unsigned int voltage_steps_optional_range;
459 	unsigned int max_voltage_offset_optional_range;
460 	unsigned int time_steps;
461 	unsigned int max_time_offset;
462 	unsigned int voltage_time_offset;
463 	unsigned int dwell_time;
464 	enum usb4_margin_sw_error_counter error_counter;
465 	bool optional_voltage_offset_range;
466 	bool software;
467 	bool time;
468 	bool right_high;
469 	bool upper_eye;
470 };
471 
472 static int margining_modify_error_counter(struct tb_margining *margining,
473 	u32 lanes, enum usb4_margin_sw_error_counter error_counter)
474 {
475 	struct usb4_port_margining_params params = { 0 };
476 	struct tb_port *port = margining->port;
477 	u32 result;
478 
479 	if (error_counter != USB4_MARGIN_SW_ERROR_COUNTER_CLEAR &&
480 	    error_counter != USB4_MARGIN_SW_ERROR_COUNTER_STOP)
481 		return -EOPNOTSUPP;
482 
483 	params.error_counter = error_counter;
484 	params.lanes = lanes;
485 
486 	return usb4_port_sw_margin(port, margining->target, margining->index,
487 				   &params, &result);
488 }
489 
490 static bool supports_software(const struct tb_margining *margining)
491 {
492 	if (margining->gen < 4)
493 		return margining->caps[0] & USB4_MARGIN_CAP_0_MODES_SW;
494 	return margining->caps[2] & USB4_MARGIN_CAP_2_MODES_SW;
495 }
496 
497 static bool supports_hardware(const struct tb_margining *margining)
498 {
499 	if (margining->gen < 4)
500 		return margining->caps[0] & USB4_MARGIN_CAP_0_MODES_HW;
501 	return margining->caps[2] & USB4_MARGIN_CAP_2_MODES_HW;
502 }
503 
504 static bool all_lanes(const struct tb_margining *margining)
505 {
506 	return margining->caps[0] & USB4_MARGIN_CAP_0_ALL_LANES;
507 }
508 
509 static enum usb4_margin_cap_voltage_indp
510 independent_voltage_margins(const struct tb_margining *margining)
511 {
512 	if (margining->gen < 4) {
513 		switch (FIELD_GET(USB4_MARGIN_CAP_0_VOLTAGE_INDP_MASK, margining->caps[0])) {
514 		case USB4_MARGIN_CAP_0_VOLTAGE_MIN:
515 			return USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_MIN;
516 		case USB4_MARGIN_CAP_0_VOLTAGE_HL:
517 			return USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_HL;
518 		case USB4_MARGIN_CAP_1_TIME_BOTH:
519 			return USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_BOTH;
520 		}
521 	} else {
522 		switch (FIELD_GET(USB4_MARGIN_CAP_2_VOLTAGE_INDP_MASK, margining->caps[2])) {
523 		case USB4_MARGIN_CAP_2_VOLTAGE_MIN:
524 			return USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_4_MIN;
525 		case USB4_MARGIN_CAP_2_VOLTAGE_BOTH:
526 			return USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_4_BOTH;
527 		}
528 	}
529 	return USB4_MARGIN_CAP_VOLTAGE_INDP_UNKNOWN;
530 }
531 
532 static bool supports_time(const struct tb_margining *margining)
533 {
534 	if (margining->gen < 4)
535 		return margining->caps[0] & USB4_MARGIN_CAP_0_TIME;
536 	return margining->caps[2] & USB4_MARGIN_CAP_2_TIME;
537 }
538 
539 /* Only applicable if supports_time() returns true */
540 static enum usb4_margin_cap_time_indp
541 independent_time_margins(const struct tb_margining *margining)
542 {
543 	if (margining->gen < 4) {
544 		switch (FIELD_GET(USB4_MARGIN_CAP_1_TIME_INDP_MASK, margining->caps[1])) {
545 		case USB4_MARGIN_CAP_1_TIME_MIN:
546 			return USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_MIN;
547 		case USB4_MARGIN_CAP_1_TIME_LR:
548 			return USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_LR;
549 		case USB4_MARGIN_CAP_1_TIME_BOTH:
550 			return USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_BOTH;
551 		}
552 	} else {
553 		switch (FIELD_GET(USB4_MARGIN_CAP_2_TIME_INDP_MASK, margining->caps[2])) {
554 		case USB4_MARGIN_CAP_2_TIME_MIN:
555 			return USB4_MARGIN_CAP_TIME_INDP_GEN_4_MIN;
556 		case USB4_MARGIN_CAP_2_TIME_BOTH:
557 			return USB4_MARGIN_CAP_TIME_INDP_GEN_4_BOTH;
558 		}
559 	}
560 	return USB4_MARGIN_CAP_TIME_INDP_UNKNOWN;
561 }
562 
563 static bool
564 supports_optional_voltage_offset_range(const struct tb_margining *margining)
565 {
566 	return margining->caps[0] & USB4_MARGIN_CAP_0_OPT_VOLTAGE_SUPPORT;
567 }
568 
569 static ssize_t
570 margining_ber_level_write(struct file *file, const char __user *user_buf,
571 			   size_t count, loff_t *ppos)
572 {
573 	struct seq_file *s = file->private_data;
574 	struct tb_margining *margining = s->private;
575 	struct tb *tb = margining->port->sw->tb;
576 	unsigned int val;
577 	int ret = 0;
578 	char *buf;
579 
580 	if (mutex_lock_interruptible(&tb->lock))
581 		return -ERESTARTSYS;
582 
583 	if (margining->software) {
584 		ret = -EINVAL;
585 		goto out_unlock;
586 	}
587 
588 	buf = validate_and_copy_from_user(user_buf, &count);
589 	if (IS_ERR(buf)) {
590 		ret = PTR_ERR(buf);
591 		goto out_unlock;
592 	}
593 
594 	buf[count - 1] = '\0';
595 
596 	ret = kstrtouint(buf, 10, &val);
597 	if (ret)
598 		goto out_free;
599 
600 	if (val < margining->min_ber_level ||
601 	    val > margining->max_ber_level) {
602 		ret = -EINVAL;
603 		goto out_free;
604 	}
605 
606 	margining->ber_level = val;
607 
608 out_free:
609 	free_page((unsigned long)buf);
610 out_unlock:
611 	mutex_unlock(&tb->lock);
612 
613 	return ret < 0 ? ret : count;
614 }
615 
616 static void ber_level_show(struct seq_file *s, unsigned int val)
617 {
618 	if (val % 2)
619 		seq_printf(s, "3 * 1e%d (%u)\n", -12 + (val + 1) / 2, val);
620 	else
621 		seq_printf(s, "1e%d (%u)\n", -12 + val / 2, val);
622 }
623 
624 static int margining_ber_level_show(struct seq_file *s, void *not_used)
625 {
626 	const struct tb_margining *margining = s->private;
627 
628 	if (margining->software)
629 		return -EINVAL;
630 	ber_level_show(s, margining->ber_level);
631 	return 0;
632 }
633 DEBUGFS_ATTR_RW(margining_ber_level);
634 
635 static int margining_caps_show(struct seq_file *s, void *not_used)
636 {
637 	struct tb_margining *margining = s->private;
638 	struct tb *tb = margining->port->sw->tb;
639 	int ret = 0;
640 
641 	if (mutex_lock_interruptible(&tb->lock))
642 		return -ERESTARTSYS;
643 
644 	/* Dump the raw caps first */
645 	for (int i = 0; i < ARRAY_SIZE(margining->caps); i++)
646 		seq_printf(s, "0x%08x\n", margining->caps[i]);
647 
648 	seq_printf(s, "# software margining: %s\n",
649 		   supports_software(margining) ? "yes" : "no");
650 	if (supports_hardware(margining)) {
651 		seq_puts(s, "# hardware margining: yes\n");
652 		seq_puts(s, "# minimum BER level contour: ");
653 		ber_level_show(s, margining->min_ber_level);
654 		seq_puts(s, "# maximum BER level contour: ");
655 		ber_level_show(s, margining->max_ber_level);
656 	} else {
657 		seq_puts(s, "# hardware margining: no\n");
658 	}
659 
660 	seq_printf(s, "# all lanes simultaneously: %s\n",
661 		  str_yes_no(all_lanes(margining)));
662 	seq_printf(s, "# voltage margin steps: %u\n",
663 		   margining->voltage_steps);
664 	seq_printf(s, "# maximum voltage offset: %u mV\n",
665 		   margining->max_voltage_offset);
666 	seq_printf(s, "# optional voltage offset range support: %s\n",
667 		   str_yes_no(supports_optional_voltage_offset_range(margining)));
668 	if (supports_optional_voltage_offset_range(margining)) {
669 		seq_printf(s, "# voltage margin steps, optional range: %u\n",
670 			   margining->voltage_steps_optional_range);
671 		seq_printf(s, "# maximum voltage offset, optional range: %u mV\n",
672 			   margining->max_voltage_offset_optional_range);
673 	}
674 
675 	switch (independent_voltage_margins(margining)) {
676 	case USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_MIN:
677 		seq_puts(s, "# returns minimum between high and low voltage margins\n");
678 		break;
679 	case USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_HL:
680 		seq_puts(s, "# returns high or low voltage margin\n");
681 		break;
682 	case USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_BOTH:
683 		seq_puts(s, "# returns both high and low margins\n");
684 		break;
685 	case USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_4_MIN:
686 		seq_puts(s, "# returns minimum between high and low voltage margins in both lower and upper eye\n");
687 		break;
688 	case USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_4_BOTH:
689 		seq_puts(s, "# returns both high and low margins of both upper and lower eye\n");
690 		break;
691 	case USB4_MARGIN_CAP_VOLTAGE_INDP_UNKNOWN:
692 		tb_port_warn(margining->port,
693 			     "failed to parse independent voltage margining capabilities\n");
694 		ret = -EIO;
695 		goto out;
696 	}
697 
698 	if (supports_time(margining)) {
699 		seq_puts(s, "# time margining: yes\n");
700 		seq_printf(s, "# time margining is destructive: %s\n",
701 			   str_yes_no(margining->caps[1] & USB4_MARGIN_CAP_1_TIME_DESTR));
702 
703 		switch (independent_time_margins(margining)) {
704 		case USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_MIN:
705 			seq_puts(s, "# returns minimum between left and right time margins\n");
706 			break;
707 		case USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_LR:
708 			seq_puts(s, "# returns left or right margin\n");
709 			break;
710 		case USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_BOTH:
711 			seq_puts(s, "# returns both left and right margins\n");
712 			break;
713 		case USB4_MARGIN_CAP_TIME_INDP_GEN_4_MIN:
714 			seq_puts(s, "# returns minimum between left and right time margins in both lower and upper eye\n");
715 			break;
716 		case USB4_MARGIN_CAP_TIME_INDP_GEN_4_BOTH:
717 			seq_puts(s, "# returns both left and right margins of both upper and lower eye\n");
718 			break;
719 		case USB4_MARGIN_CAP_TIME_INDP_UNKNOWN:
720 			tb_port_warn(margining->port,
721 				     "failed to parse independent time margining capabilities\n");
722 			ret = -EIO;
723 			goto out;
724 		}
725 
726 		seq_printf(s, "# time margin steps: %u\n",
727 			   margining->time_steps);
728 		seq_printf(s, "# maximum time offset: %u mUI\n",
729 			   margining->max_time_offset);
730 	} else {
731 		seq_puts(s, "# time margining: no\n");
732 	}
733 
734 out:
735 	mutex_unlock(&tb->lock);
736 	return ret;
737 }
738 DEBUGFS_ATTR_RO(margining_caps);
739 
740 static const struct {
741 	enum usb4_margining_lane lane;
742 	const char *name;
743 } lane_names[] = {
744 	{
745 		.lane = USB4_MARGINING_LANE_RX0,
746 		.name = "0",
747 	},
748 	{
749 		.lane = USB4_MARGINING_LANE_RX1,
750 		.name = "1",
751 	},
752 	{
753 		.lane = USB4_MARGINING_LANE_RX2,
754 		.name = "2",
755 	},
756 	{
757 		.lane = USB4_MARGINING_LANE_ALL,
758 		.name = "all",
759 	},
760 };
761 
762 static ssize_t
763 margining_lanes_write(struct file *file, const char __user *user_buf,
764 		      size_t count, loff_t *ppos)
765 {
766 	struct seq_file *s = file->private_data;
767 	struct tb_margining *margining = s->private;
768 	struct tb_port *port = margining->port;
769 	struct tb *tb = port->sw->tb;
770 	int lane = -1;
771 	char *buf;
772 
773 	buf = validate_and_copy_from_user(user_buf, &count);
774 	if (IS_ERR(buf))
775 		return PTR_ERR(buf);
776 
777 	buf[count - 1] = '\0';
778 
779 	for (int i = 0; i < ARRAY_SIZE(lane_names); i++) {
780 		if (!strcmp(buf, lane_names[i].name)) {
781 			lane = lane_names[i].lane;
782 			break;
783 		}
784 	}
785 
786 	free_page((unsigned long)buf);
787 
788 	if (lane == -1)
789 		return -EINVAL;
790 
791 	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
792 		if (lane == USB4_MARGINING_LANE_ALL && !all_lanes(margining))
793 			return -EINVAL;
794 		/*
795 		 * Enabling on RX2 requires that it is supported by the
796 		 * USB4 port.
797 		 */
798 		if (lane == USB4_MARGINING_LANE_RX2 && !margining->asym_rx)
799 			return -EINVAL;
800 
801 		margining->lanes = lane;
802 	}
803 
804 	return count;
805 }
806 
807 static int margining_lanes_show(struct seq_file *s, void *not_used)
808 {
809 	struct tb_margining *margining = s->private;
810 	struct tb_port *port = margining->port;
811 	struct tb *tb = port->sw->tb;
812 
813 	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
814 		for (int i = 0; i < ARRAY_SIZE(lane_names); i++) {
815 			if (lane_names[i].lane == USB4_MARGINING_LANE_ALL &&
816 			    !all_lanes(margining))
817 				continue;
818 			if (lane_names[i].lane == USB4_MARGINING_LANE_RX2 &&
819 			    !margining->asym_rx)
820 				continue;
821 
822 			if (i != 0)
823 				seq_putc(s, ' ');
824 
825 			if (lane_names[i].lane == margining->lanes)
826 				seq_printf(s, "[%s]", lane_names[i].name);
827 			else
828 				seq_printf(s, "%s", lane_names[i].name);
829 		}
830 		seq_puts(s, "\n");
831 	}
832 
833 	return 0;
834 }
835 DEBUGFS_ATTR_RW(margining_lanes);
836 
837 static ssize_t
838 margining_voltage_time_offset_write(struct file *file,
839 				    const char __user *user_buf,
840 				    size_t count, loff_t *ppos)
841 {
842 	struct seq_file *s = file->private_data;
843 	struct tb_margining *margining = s->private;
844 	struct tb *tb = margining->port->sw->tb;
845 	unsigned int max_margin;
846 	unsigned int val;
847 	int ret;
848 
849 	ret = kstrtouint_from_user(user_buf, count, 10, &val);
850 	if (ret)
851 		return ret;
852 
853 	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
854 		if (!margining->software)
855 			return -EOPNOTSUPP;
856 
857 		if (margining->time)
858 			max_margin = margining->time_steps;
859 		else
860 			if (margining->optional_voltage_offset_range)
861 				max_margin = margining->voltage_steps_optional_range;
862 			else
863 				max_margin = margining->voltage_steps;
864 
865 		margining->voltage_time_offset = clamp(val, 0, max_margin);
866 	}
867 
868 	return count;
869 }
870 
871 static int margining_voltage_time_offset_show(struct seq_file *s,
872 					      void *not_used)
873 {
874 	const struct tb_margining *margining = s->private;
875 	struct tb *tb = margining->port->sw->tb;
876 
877 	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
878 		if (!margining->software)
879 			return -EOPNOTSUPP;
880 
881 		seq_printf(s, "%d\n", margining->voltage_time_offset);
882 	}
883 
884 	return 0;
885 }
886 DEBUGFS_ATTR_RW(margining_voltage_time_offset);
887 
888 static ssize_t
889 margining_error_counter_write(struct file *file, const char __user *user_buf,
890 			      size_t count, loff_t *ppos)
891 {
892 	enum usb4_margin_sw_error_counter error_counter;
893 	struct seq_file *s = file->private_data;
894 	struct tb_margining *margining = s->private;
895 	struct tb *tb = margining->port->sw->tb;
896 	char *buf;
897 
898 	buf = validate_and_copy_from_user(user_buf, &count);
899 	if (IS_ERR(buf))
900 		return PTR_ERR(buf);
901 
902 	buf[count - 1] = '\0';
903 
904 	if (!strcmp(buf, "nop"))
905 		error_counter = USB4_MARGIN_SW_ERROR_COUNTER_NOP;
906 	else if (!strcmp(buf, "clear"))
907 		error_counter = USB4_MARGIN_SW_ERROR_COUNTER_CLEAR;
908 	else if (!strcmp(buf, "start"))
909 		error_counter = USB4_MARGIN_SW_ERROR_COUNTER_START;
910 	else if (!strcmp(buf, "stop"))
911 		error_counter = USB4_MARGIN_SW_ERROR_COUNTER_STOP;
912 	else
913 		return -EINVAL;
914 
915 	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
916 		if (!margining->software)
917 			return -EOPNOTSUPP;
918 
919 		margining->error_counter = error_counter;
920 	}
921 
922 	return count;
923 }
924 
925 static int margining_error_counter_show(struct seq_file *s, void *not_used)
926 {
927 	const struct tb_margining *margining = s->private;
928 	struct tb *tb = margining->port->sw->tb;
929 
930 	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
931 		if (!margining->software)
932 			return -EOPNOTSUPP;
933 
934 		switch (margining->error_counter) {
935 		case USB4_MARGIN_SW_ERROR_COUNTER_NOP:
936 			seq_puts(s, "[nop] clear start stop\n");
937 			break;
938 		case USB4_MARGIN_SW_ERROR_COUNTER_CLEAR:
939 			seq_puts(s, "nop [clear] start stop\n");
940 			break;
941 		case USB4_MARGIN_SW_ERROR_COUNTER_START:
942 			seq_puts(s, "nop clear [start] stop\n");
943 			break;
944 		case USB4_MARGIN_SW_ERROR_COUNTER_STOP:
945 			seq_puts(s, "nop clear start [stop]\n");
946 			break;
947 		}
948 	}
949 
950 	return 0;
951 }
952 DEBUGFS_ATTR_RW(margining_error_counter);
953 
954 static ssize_t
955 margining_dwell_time_write(struct file *file, const char __user *user_buf,
956 			   size_t count, loff_t *ppos)
957 {
958 	struct seq_file *s = file->private_data;
959 	struct tb_margining *margining = s->private;
960 	struct tb *tb = margining->port->sw->tb;
961 	unsigned int val;
962 	int ret;
963 
964 	ret = kstrtouint_from_user(user_buf, count, 10, &val);
965 	if (ret)
966 		return ret;
967 
968 	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
969 		if (!margining->software)
970 			return -EOPNOTSUPP;
971 
972 		margining->dwell_time = clamp(val, MIN_DWELL_TIME, MAX_DWELL_TIME);
973 	}
974 
975 	return count;
976 }
977 
978 static int margining_dwell_time_show(struct seq_file *s, void *not_used)
979 {
980 	struct tb_margining *margining = s->private;
981 	struct tb *tb = margining->port->sw->tb;
982 
983 	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
984 		if (!margining->software)
985 			return -EOPNOTSUPP;
986 
987 		seq_printf(s, "%d\n", margining->dwell_time);
988 	}
989 
990 	return 0;
991 }
992 DEBUGFS_ATTR_RW(margining_dwell_time);
993 
994 static ssize_t
995 margining_optional_voltage_offset_write(struct file *file, const char __user *user_buf,
996 					size_t count, loff_t *ppos)
997 {
998 	struct seq_file *s = file->private_data;
999 	struct tb_margining *margining = s->private;
1000 	struct tb *tb = margining->port->sw->tb;
1001 	bool val;
1002 	int ret;
1003 
1004 	ret = kstrtobool_from_user(user_buf, count, &val);
1005 	if (ret)
1006 		return ret;
1007 
1008 	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
1009 		margining->optional_voltage_offset_range = val;
1010 	}
1011 
1012 	return count;
1013 }
1014 
1015 static int margining_optional_voltage_offset_show(struct seq_file *s,
1016 						  void *not_used)
1017 {
1018 	struct tb_margining *margining = s->private;
1019 	struct tb *tb = margining->port->sw->tb;
1020 
1021 	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
1022 		seq_printf(s, "%u\n", margining->optional_voltage_offset_range);
1023 	}
1024 
1025 	return 0;
1026 }
1027 DEBUGFS_ATTR_RW(margining_optional_voltage_offset);
1028 
1029 static ssize_t margining_mode_write(struct file *file,
1030 				   const char __user *user_buf,
1031 				   size_t count, loff_t *ppos)
1032 {
1033 	struct seq_file *s = file->private_data;
1034 	struct tb_margining *margining = s->private;
1035 	struct tb *tb = margining->port->sw->tb;
1036 	int ret = 0;
1037 	char *buf;
1038 
1039 	buf = validate_and_copy_from_user(user_buf, &count);
1040 	if (IS_ERR(buf))
1041 		return PTR_ERR(buf);
1042 
1043 	buf[count - 1] = '\0';
1044 
1045 	if (mutex_lock_interruptible(&tb->lock)) {
1046 		ret = -ERESTARTSYS;
1047 		goto out_free;
1048 	}
1049 
1050 	if (!strcmp(buf, "software")) {
1051 		if (supports_software(margining))
1052 			margining->software = true;
1053 		else
1054 			ret = -EINVAL;
1055 	} else if (!strcmp(buf, "hardware")) {
1056 		if (supports_hardware(margining))
1057 			margining->software = false;
1058 		else
1059 			ret = -EINVAL;
1060 	} else {
1061 		ret = -EINVAL;
1062 	}
1063 
1064 	mutex_unlock(&tb->lock);
1065 
1066 out_free:
1067 	free_page((unsigned long)buf);
1068 	return ret ? ret : count;
1069 }
1070 
1071 static int margining_mode_show(struct seq_file *s, void *not_used)
1072 {
1073 	struct tb_margining *margining = s->private;
1074 	struct tb *tb = margining->port->sw->tb;
1075 	const char *space = "";
1076 
1077 	if (mutex_lock_interruptible(&tb->lock))
1078 		return -ERESTARTSYS;
1079 
1080 	if (supports_software(margining)) {
1081 		if (margining->software)
1082 			seq_puts(s, "[software]");
1083 		else
1084 			seq_puts(s, "software");
1085 		space = " ";
1086 	}
1087 	if (supports_hardware(margining)) {
1088 		if (margining->software)
1089 			seq_printf(s, "%shardware", space);
1090 		else
1091 			seq_printf(s, "%s[hardware]", space);
1092 	}
1093 
1094 	mutex_unlock(&tb->lock);
1095 
1096 	seq_puts(s, "\n");
1097 	return 0;
1098 }
1099 DEBUGFS_ATTR_RW(margining_mode);
1100 
1101 static int margining_run_sw(struct tb_margining *margining,
1102 			    struct usb4_port_margining_params *params)
1103 {
1104 	u32 nsamples = margining->dwell_time / DWELL_SAMPLE_INTERVAL;
1105 	int ret, i;
1106 
1107 	ret = usb4_port_sw_margin(margining->port, margining->target, margining->index,
1108 				  params, margining->results);
1109 	if (ret)
1110 		goto out_stop;
1111 
1112 	for (i = 0; i <= nsamples; i++) {
1113 		u32 errors = 0;
1114 
1115 		ret = usb4_port_sw_margin_errors(margining->port, margining->target,
1116 						 margining->index, &margining->results[1]);
1117 		if (ret)
1118 			break;
1119 
1120 		if (margining->lanes == USB4_MARGINING_LANE_RX0)
1121 			errors = FIELD_GET(USB4_MARGIN_SW_ERR_COUNTER_LANE_0_MASK,
1122 					   margining->results[1]);
1123 		else if (margining->lanes == USB4_MARGINING_LANE_RX1)
1124 			errors = FIELD_GET(USB4_MARGIN_SW_ERR_COUNTER_LANE_1_MASK,
1125 					   margining->results[1]);
1126 		else if (margining->lanes == USB4_MARGINING_LANE_RX2)
1127 			errors = FIELD_GET(USB4_MARGIN_SW_ERR_COUNTER_LANE_2_MASK,
1128 					   margining->results[1]);
1129 		else if (margining->lanes == USB4_MARGINING_LANE_ALL)
1130 			errors = margining->results[1];
1131 
1132 		/* Any errors stop the test */
1133 		if (errors)
1134 			break;
1135 
1136 		fsleep(DWELL_SAMPLE_INTERVAL * USEC_PER_MSEC);
1137 	}
1138 
1139 out_stop:
1140 	/*
1141 	 * Stop the counters but don't clear them to allow the
1142 	 * different error counter configurations.
1143 	 */
1144 	margining_modify_error_counter(margining, margining->lanes,
1145 				       USB4_MARGIN_SW_ERROR_COUNTER_STOP);
1146 	return ret;
1147 }
1148 
1149 static int validate_margining(struct tb_margining *margining)
1150 {
1151 	/*
1152 	 * For running on RX2 the link must be asymmetric with 3
1153 	 * receivers. Because this is can change dynamically, check it
1154 	 * here before we start the margining and report back error if
1155 	 * expectations are not met.
1156 	 */
1157 	if (margining->lanes == USB4_MARGINING_LANE_RX2) {
1158 		int ret;
1159 
1160 		ret = tb_port_get_link_width(margining->port);
1161 		if (ret < 0)
1162 			return ret;
1163 		if (ret != TB_LINK_WIDTH_ASYM_RX) {
1164 			tb_port_warn(margining->port, "link is %s expected %s",
1165 				     tb_width_name(ret),
1166 				     tb_width_name(TB_LINK_WIDTH_ASYM_RX));
1167 			return -EINVAL;
1168 		}
1169 	}
1170 
1171 	return 0;
1172 }
1173 
1174 static int margining_run_write(void *data, u64 val)
1175 {
1176 	struct tb_margining *margining = data;
1177 	struct tb_port *port = margining->port;
1178 	struct device *dev = margining->dev;
1179 	struct tb_switch *sw = port->sw;
1180 	struct tb_switch *down_sw;
1181 	struct tb *tb = sw->tb;
1182 	int ret, clx;
1183 
1184 	if (val != 1)
1185 		return -EINVAL;
1186 
1187 	pm_runtime_get_sync(dev);
1188 
1189 	if (mutex_lock_interruptible(&tb->lock)) {
1190 		ret = -ERESTARTSYS;
1191 		goto out_rpm_put;
1192 	}
1193 
1194 	ret = validate_margining(margining);
1195 	if (ret)
1196 		goto out_unlock;
1197 
1198 	if (tb_is_upstream_port(port))
1199 		down_sw = sw;
1200 	else if (port->remote)
1201 		down_sw = port->remote->sw;
1202 	else
1203 		down_sw = NULL;
1204 
1205 	if (down_sw) {
1206 		/*
1207 		 * CL states may interfere with lane margining so
1208 		 * disable them temporarily now.
1209 		 */
1210 		ret = tb_switch_clx_disable(down_sw);
1211 		if (ret < 0) {
1212 			tb_sw_warn(down_sw, "failed to disable CL states\n");
1213 			goto out_unlock;
1214 		}
1215 		clx = ret;
1216 	}
1217 
1218 	/* Clear the results */
1219 	memset(margining->results, 0, sizeof(margining->results));
1220 
1221 	if (margining->software) {
1222 		struct usb4_port_margining_params params = {
1223 			.error_counter = USB4_MARGIN_SW_ERROR_COUNTER_CLEAR,
1224 			.lanes = margining->lanes,
1225 			.time = margining->time,
1226 			.voltage_time_offset = margining->voltage_time_offset,
1227 			.right_high = margining->right_high,
1228 			.upper_eye = margining->upper_eye,
1229 			.optional_voltage_offset_range = margining->optional_voltage_offset_range,
1230 		};
1231 
1232 		tb_port_dbg(port,
1233 			    "running software %s lane margining for %s lanes %u\n",
1234 			    margining->time ? "time" : "voltage", dev_name(dev),
1235 			    margining->lanes);
1236 
1237 		ret = margining_run_sw(margining, &params);
1238 	} else {
1239 		struct usb4_port_margining_params params = {
1240 			.ber_level = margining->ber_level,
1241 			.lanes = margining->lanes,
1242 			.time = margining->time,
1243 			.right_high = margining->right_high,
1244 			.upper_eye = margining->upper_eye,
1245 			.optional_voltage_offset_range = margining->optional_voltage_offset_range,
1246 		};
1247 
1248 		tb_port_dbg(port,
1249 			    "running hardware %s lane margining for %s lanes %u\n",
1250 			    margining->time ? "time" : "voltage", dev_name(dev),
1251 			    margining->lanes);
1252 
1253 		ret = usb4_port_hw_margin(port, margining->target, margining->index, &params,
1254 					  margining->results, ARRAY_SIZE(margining->results));
1255 	}
1256 
1257 	if (down_sw)
1258 		tb_switch_clx_enable(down_sw, clx);
1259 out_unlock:
1260 	mutex_unlock(&tb->lock);
1261 out_rpm_put:
1262 	pm_runtime_mark_last_busy(dev);
1263 	pm_runtime_put_autosuspend(dev);
1264 
1265 	return ret;
1266 }
1267 DEFINE_DEBUGFS_ATTRIBUTE(margining_run_fops, NULL, margining_run_write,
1268 			 "%llu\n");
1269 
1270 static ssize_t margining_results_write(struct file *file,
1271 				       const char __user *user_buf,
1272 				       size_t count, loff_t *ppos)
1273 {
1274 	struct seq_file *s = file->private_data;
1275 	struct tb_margining *margining = s->private;
1276 	struct tb *tb = margining->port->sw->tb;
1277 
1278 	if (mutex_lock_interruptible(&tb->lock))
1279 		return -ERESTARTSYS;
1280 
1281 	/* Just clear the results */
1282 	memset(margining->results, 0, sizeof(margining->results));
1283 
1284 	if (margining->software) {
1285 		/* Clear the error counters */
1286 		margining_modify_error_counter(margining,
1287 					       USB4_MARGINING_LANE_ALL,
1288 					       USB4_MARGIN_SW_ERROR_COUNTER_CLEAR);
1289 	}
1290 
1291 	mutex_unlock(&tb->lock);
1292 	return count;
1293 }
1294 
1295 static void voltage_margin_show(struct seq_file *s,
1296 				const struct tb_margining *margining, u8 val)
1297 {
1298 	unsigned int tmp, voltage;
1299 
1300 	tmp = FIELD_GET(USB4_MARGIN_HW_RES_MARGIN_MASK, val);
1301 	voltage = tmp * margining->max_voltage_offset / margining->voltage_steps;
1302 	seq_printf(s, "%u mV (%u)", voltage, tmp);
1303 	if (val & USB4_MARGIN_HW_RES_EXCEEDS)
1304 		seq_puts(s, " exceeds maximum");
1305 	seq_puts(s, "\n");
1306 	if (margining->optional_voltage_offset_range)
1307 		seq_puts(s, " optional voltage offset range enabled\n");
1308 }
1309 
1310 static void time_margin_show(struct seq_file *s,
1311 			     const struct tb_margining *margining, u8 val)
1312 {
1313 	unsigned int tmp, interval;
1314 
1315 	tmp = FIELD_GET(USB4_MARGIN_HW_RES_MARGIN_MASK, val);
1316 	interval = tmp * margining->max_time_offset / margining->time_steps;
1317 	seq_printf(s, "%u mUI (%u)", interval, tmp);
1318 	if (val & USB4_MARGIN_HW_RES_EXCEEDS)
1319 		seq_puts(s, " exceeds maximum");
1320 	seq_puts(s, "\n");
1321 }
1322 
1323 static u8 margining_hw_result_val(const u32 *results,
1324 				  enum usb4_margining_lane lane,
1325 				  bool right_high)
1326 {
1327 	u32 val;
1328 
1329 	if (lane == USB4_MARGINING_LANE_RX0)
1330 		val = results[1];
1331 	else if (lane == USB4_MARGINING_LANE_RX1)
1332 		val = results[1] >> USB4_MARGIN_HW_RES_LANE_SHIFT;
1333 	else if (lane == USB4_MARGINING_LANE_RX2)
1334 		val = results[2];
1335 	else
1336 		val = 0;
1337 
1338 	return right_high ? val : val >> USB4_MARGIN_HW_RES_LL_SHIFT;
1339 }
1340 
1341 static void margining_hw_result_format(struct seq_file *s,
1342 				       const struct tb_margining *margining,
1343 				       enum usb4_margining_lane lane)
1344 {
1345 	u8 val;
1346 
1347 	if (margining->time) {
1348 		val = margining_hw_result_val(margining->results, lane, true);
1349 		seq_printf(s, "# lane %u right time margin: ", lane);
1350 		time_margin_show(s, margining, val);
1351 		val = margining_hw_result_val(margining->results, lane, false);
1352 		seq_printf(s, "# lane %u left time margin: ", lane);
1353 		time_margin_show(s, margining, val);
1354 	} else {
1355 		val = margining_hw_result_val(margining->results, lane, true);
1356 		seq_printf(s, "# lane %u high voltage margin: ", lane);
1357 		voltage_margin_show(s, margining, val);
1358 		val = margining_hw_result_val(margining->results, lane, false);
1359 		seq_printf(s, "# lane %u low voltage margin: ", lane);
1360 		voltage_margin_show(s, margining, val);
1361 	}
1362 }
1363 
1364 static int margining_results_show(struct seq_file *s, void *not_used)
1365 {
1366 	struct tb_margining *margining = s->private;
1367 	struct tb *tb = margining->port->sw->tb;
1368 
1369 	if (mutex_lock_interruptible(&tb->lock))
1370 		return -ERESTARTSYS;
1371 
1372 	/* Dump the raw results first */
1373 	seq_printf(s, "0x%08x\n", margining->results[0]);
1374 	/* Only the hardware margining has two result dwords */
1375 	if (!margining->software) {
1376 		for (int i = 1; i < ARRAY_SIZE(margining->results); i++)
1377 			seq_printf(s, "0x%08x\n", margining->results[i]);
1378 
1379 		if (margining->lanes == USB4_MARGINING_LANE_ALL) {
1380 			margining_hw_result_format(s, margining,
1381 						   USB4_MARGINING_LANE_RX0);
1382 			margining_hw_result_format(s, margining,
1383 						   USB4_MARGINING_LANE_RX1);
1384 			if (margining->asym_rx)
1385 				margining_hw_result_format(s, margining,
1386 						USB4_MARGINING_LANE_RX2);
1387 		} else {
1388 			margining_hw_result_format(s, margining,
1389 						   margining->lanes);
1390 		}
1391 	} else {
1392 		u32 lane_errors, result;
1393 
1394 		seq_printf(s, "0x%08x\n", margining->results[1]);
1395 
1396 		result = FIELD_GET(USB4_MARGIN_SW_LANES_MASK, margining->results[0]);
1397 		if (result == USB4_MARGINING_LANE_RX0 ||
1398 		    result == USB4_MARGINING_LANE_ALL) {
1399 			lane_errors = FIELD_GET(USB4_MARGIN_SW_ERR_COUNTER_LANE_0_MASK,
1400 						margining->results[1]);
1401 			seq_printf(s, "# lane 0 errors: %u\n", lane_errors);
1402 		}
1403 		if (result == USB4_MARGINING_LANE_RX1 ||
1404 		    result == USB4_MARGINING_LANE_ALL) {
1405 			lane_errors = FIELD_GET(USB4_MARGIN_SW_ERR_COUNTER_LANE_1_MASK,
1406 						margining->results[1]);
1407 			seq_printf(s, "# lane 1 errors: %u\n", lane_errors);
1408 		}
1409 		if (margining->asym_rx &&
1410 		    (result == USB4_MARGINING_LANE_RX2 ||
1411 		     result == USB4_MARGINING_LANE_ALL)) {
1412 			lane_errors = FIELD_GET(USB4_MARGIN_SW_ERR_COUNTER_LANE_2_MASK,
1413 						margining->results[1]);
1414 			seq_printf(s, "# lane 2 errors: %u\n", lane_errors);
1415 		}
1416 	}
1417 
1418 	mutex_unlock(&tb->lock);
1419 	return 0;
1420 }
1421 DEBUGFS_ATTR_RW(margining_results);
1422 
1423 static ssize_t margining_test_write(struct file *file,
1424 				    const char __user *user_buf,
1425 				    size_t count, loff_t *ppos)
1426 {
1427 	struct seq_file *s = file->private_data;
1428 	struct tb_margining *margining = s->private;
1429 	struct tb *tb = margining->port->sw->tb;
1430 	int ret = 0;
1431 	char *buf;
1432 
1433 	buf = validate_and_copy_from_user(user_buf, &count);
1434 	if (IS_ERR(buf))
1435 		return PTR_ERR(buf);
1436 
1437 	buf[count - 1] = '\0';
1438 
1439 	if (mutex_lock_interruptible(&tb->lock)) {
1440 		ret = -ERESTARTSYS;
1441 		goto out_free;
1442 	}
1443 
1444 	if (!strcmp(buf, "time") && supports_time(margining))
1445 		margining->time = true;
1446 	else if (!strcmp(buf, "voltage"))
1447 		margining->time = false;
1448 	else
1449 		ret = -EINVAL;
1450 
1451 	mutex_unlock(&tb->lock);
1452 
1453 out_free:
1454 	free_page((unsigned long)buf);
1455 	return ret ? ret : count;
1456 }
1457 
1458 static int margining_test_show(struct seq_file *s, void *not_used)
1459 {
1460 	struct tb_margining *margining = s->private;
1461 	struct tb *tb = margining->port->sw->tb;
1462 
1463 	if (mutex_lock_interruptible(&tb->lock))
1464 		return -ERESTARTSYS;
1465 
1466 	if (supports_time(margining)) {
1467 		if (margining->time)
1468 			seq_puts(s, "voltage [time]\n");
1469 		else
1470 			seq_puts(s, "[voltage] time\n");
1471 	} else {
1472 		seq_puts(s, "[voltage]\n");
1473 	}
1474 
1475 	mutex_unlock(&tb->lock);
1476 	return 0;
1477 }
1478 DEBUGFS_ATTR_RW(margining_test);
1479 
1480 static ssize_t margining_margin_write(struct file *file,
1481 				    const char __user *user_buf,
1482 				    size_t count, loff_t *ppos)
1483 {
1484 	struct seq_file *s = file->private_data;
1485 	struct tb_margining *margining = s->private;
1486 	struct tb *tb = margining->port->sw->tb;
1487 	int ret = 0;
1488 	char *buf;
1489 
1490 	buf = validate_and_copy_from_user(user_buf, &count);
1491 	if (IS_ERR(buf))
1492 		return PTR_ERR(buf);
1493 
1494 	buf[count - 1] = '\0';
1495 
1496 	if (mutex_lock_interruptible(&tb->lock)) {
1497 		ret = -ERESTARTSYS;
1498 		goto out_free;
1499 	}
1500 
1501 	if (margining->time) {
1502 		if (!strcmp(buf, "left"))
1503 			margining->right_high = false;
1504 		else if (!strcmp(buf, "right"))
1505 			margining->right_high = true;
1506 		else
1507 			ret = -EINVAL;
1508 	} else {
1509 		if (!strcmp(buf, "low"))
1510 			margining->right_high = false;
1511 		else if (!strcmp(buf, "high"))
1512 			margining->right_high = true;
1513 		else
1514 			ret = -EINVAL;
1515 	}
1516 
1517 	mutex_unlock(&tb->lock);
1518 
1519 out_free:
1520 	free_page((unsigned long)buf);
1521 	return ret ? ret : count;
1522 }
1523 
1524 static int margining_margin_show(struct seq_file *s, void *not_used)
1525 {
1526 	struct tb_margining *margining = s->private;
1527 	struct tb *tb = margining->port->sw->tb;
1528 
1529 	if (mutex_lock_interruptible(&tb->lock))
1530 		return -ERESTARTSYS;
1531 
1532 	if (margining->time) {
1533 		if (margining->right_high)
1534 			seq_puts(s, "left [right]\n");
1535 		else
1536 			seq_puts(s, "[left] right\n");
1537 	} else {
1538 		if (margining->right_high)
1539 			seq_puts(s, "low [high]\n");
1540 		else
1541 			seq_puts(s, "[low] high\n");
1542 	}
1543 
1544 	mutex_unlock(&tb->lock);
1545 	return 0;
1546 }
1547 DEBUGFS_ATTR_RW(margining_margin);
1548 
1549 static ssize_t margining_eye_write(struct file *file,
1550 				   const char __user *user_buf,
1551 				   size_t count, loff_t *ppos)
1552 {
1553 	struct seq_file *s = file->private_data;
1554 	struct tb_port *port = s->private;
1555 	struct usb4_port *usb4 = port->usb4;
1556 	struct tb *tb = port->sw->tb;
1557 	int ret = 0;
1558 	char *buf;
1559 
1560 	buf = validate_and_copy_from_user(user_buf, &count);
1561 	if (IS_ERR(buf))
1562 		return PTR_ERR(buf);
1563 
1564 	buf[count - 1] = '\0';
1565 
1566 	scoped_cond_guard(mutex_intr, ret = -ERESTARTSYS, &tb->lock) {
1567 		if (!strcmp(buf, "lower"))
1568 			usb4->margining->upper_eye = false;
1569 		else if (!strcmp(buf, "upper"))
1570 			usb4->margining->upper_eye = true;
1571 		else
1572 			ret = -EINVAL;
1573 	}
1574 
1575 	free_page((unsigned long)buf);
1576 	return ret ? ret : count;
1577 }
1578 
1579 static int margining_eye_show(struct seq_file *s, void *not_used)
1580 {
1581 	struct tb_port *port = s->private;
1582 	struct usb4_port *usb4 = port->usb4;
1583 	struct tb *tb = port->sw->tb;
1584 
1585 	scoped_guard(mutex_intr, &tb->lock) {
1586 		if (usb4->margining->upper_eye)
1587 			seq_puts(s, "lower [upper]\n");
1588 		else
1589 			seq_puts(s, "[lower] upper\n");
1590 
1591 		return 0;
1592 	}
1593 
1594 	return -ERESTARTSYS;
1595 }
1596 DEBUGFS_ATTR_RW(margining_eye);
1597 
1598 static struct tb_margining *margining_alloc(struct tb_port *port,
1599 					    struct device *dev,
1600 					    enum usb4_sb_target target,
1601 					    u8 index, struct dentry *parent)
1602 {
1603 	struct tb_margining *margining;
1604 	struct dentry *dir;
1605 	unsigned int val;
1606 	int ret;
1607 
1608 	ret = tb_port_get_link_generation(port);
1609 	if (ret < 0) {
1610 		tb_port_warn(port, "failed to read link generation\n");
1611 		return NULL;
1612 	}
1613 
1614 	margining = kzalloc(sizeof(*margining), GFP_KERNEL);
1615 	if (!margining)
1616 		return NULL;
1617 
1618 	margining->port = port;
1619 	margining->target = target;
1620 	margining->index = index;
1621 	margining->dev = dev;
1622 	margining->gen = ret;
1623 	margining->asym_rx = tb_port_width_supported(port, TB_LINK_WIDTH_ASYM_RX);
1624 
1625 	ret = usb4_port_margining_caps(port, target, index, margining->caps,
1626 				       ARRAY_SIZE(margining->caps));
1627 	if (ret) {
1628 		kfree(margining);
1629 		return NULL;
1630 	}
1631 
1632 	/* Set the initial mode */
1633 	if (supports_software(margining))
1634 		margining->software = true;
1635 
1636 	if (margining->gen < 4) {
1637 		val = FIELD_GET(USB4_MARGIN_CAP_0_VOLTAGE_STEPS_MASK, margining->caps[0]);
1638 		margining->voltage_steps = val;
1639 		val = FIELD_GET(USB4_MARGIN_CAP_0_MAX_VOLTAGE_OFFSET_MASK, margining->caps[0]);
1640 		margining->max_voltage_offset = 74 + val * 2;
1641 	} else {
1642 		val = FIELD_GET(USB4_MARGIN_CAP_2_VOLTAGE_STEPS_MASK, margining->caps[2]);
1643 		margining->voltage_steps = val;
1644 		val = FIELD_GET(USB4_MARGIN_CAP_2_MAX_VOLTAGE_OFFSET_MASK, margining->caps[2]);
1645 		margining->max_voltage_offset = 74 + val * 2;
1646 	}
1647 
1648 	if (supports_optional_voltage_offset_range(margining)) {
1649 		val = FIELD_GET(USB4_MARGIN_CAP_0_VOLT_STEPS_OPT_MASK,
1650 				margining->caps[0]);
1651 		margining->voltage_steps_optional_range = val;
1652 		val = FIELD_GET(USB4_MARGIN_CAP_1_MAX_VOLT_OFS_OPT_MASK,
1653 				margining->caps[1]);
1654 		margining->max_voltage_offset_optional_range = 74 + val * 2;
1655 	}
1656 
1657 	if (supports_time(margining)) {
1658 		val = FIELD_GET(USB4_MARGIN_CAP_1_TIME_STEPS_MASK, margining->caps[1]);
1659 		margining->time_steps = val;
1660 		val = FIELD_GET(USB4_MARGIN_CAP_1_TIME_OFFSET_MASK, margining->caps[1]);
1661 		/*
1662 		 * Store it as mUI (milli Unit Interval) because we want
1663 		 * to keep it as integer.
1664 		 */
1665 		margining->max_time_offset = 200 + 10 * val;
1666 	}
1667 
1668 	dir = debugfs_create_dir("margining", parent);
1669 	if (supports_hardware(margining)) {
1670 		val = FIELD_GET(USB4_MARGIN_CAP_1_MIN_BER_MASK, margining->caps[1]);
1671 		margining->min_ber_level = val;
1672 		val = FIELD_GET(USB4_MARGIN_CAP_1_MAX_BER_MASK, margining->caps[1]);
1673 		margining->max_ber_level = val;
1674 
1675 		/* Set the default to minimum */
1676 		margining->ber_level = margining->min_ber_level;
1677 
1678 		debugfs_create_file("ber_level_contour", 0400, dir, margining,
1679 				    &margining_ber_level_fops);
1680 	}
1681 	debugfs_create_file("caps", 0400, dir, margining, &margining_caps_fops);
1682 	debugfs_create_file("lanes", 0600, dir, margining, &margining_lanes_fops);
1683 	debugfs_create_file("mode", 0600, dir, margining, &margining_mode_fops);
1684 	debugfs_create_file("run", 0600, dir, margining, &margining_run_fops);
1685 	debugfs_create_file("results", 0600, dir, margining,
1686 			    &margining_results_fops);
1687 	debugfs_create_file("test", 0600, dir, margining, &margining_test_fops);
1688 	if (independent_voltage_margins(margining) == USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_HL ||
1689 	    (supports_time(margining) &&
1690 	     independent_time_margins(margining) == USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_LR))
1691 		debugfs_create_file("margin", 0600, dir, margining, &margining_margin_fops);
1692 
1693 	margining->error_counter = USB4_MARGIN_SW_ERROR_COUNTER_CLEAR;
1694 	margining->dwell_time = MIN_DWELL_TIME;
1695 
1696 	if (supports_optional_voltage_offset_range(margining))
1697 		debugfs_create_file("optional_voltage_offset", DEBUGFS_MODE, dir, margining,
1698 				    &margining_optional_voltage_offset_fops);
1699 
1700 	if (supports_software(margining)) {
1701 		debugfs_create_file("voltage_time_offset", DEBUGFS_MODE, dir, margining,
1702 				    &margining_voltage_time_offset_fops);
1703 		debugfs_create_file("error_counter", DEBUGFS_MODE, dir, margining,
1704 				    &margining_error_counter_fops);
1705 		debugfs_create_file("dwell_time", DEBUGFS_MODE, dir, margining,
1706 				    &margining_dwell_time_fops);
1707 	}
1708 
1709 	if (margining->gen >= 4)
1710 		debugfs_create_file("eye", 0600, dir, port, &margining_eye_fops);
1711 
1712 	return margining;
1713 }
1714 
1715 static void margining_port_init(struct tb_port *port)
1716 {
1717 	struct dentry *parent;
1718 	char dir_name[10];
1719 
1720 	if (!port->usb4)
1721 		return;
1722 
1723 	snprintf(dir_name, sizeof(dir_name), "port%d", port->port);
1724 	parent = debugfs_lookup(dir_name, port->sw->debugfs_dir);
1725 	port->usb4->margining = margining_alloc(port, &port->usb4->dev,
1726 						USB4_SB_TARGET_ROUTER, 0,
1727 						parent);
1728 }
1729 
1730 static void margining_port_remove(struct tb_port *port)
1731 {
1732 	struct dentry *parent;
1733 	char dir_name[10];
1734 
1735 	if (!port->usb4)
1736 		return;
1737 
1738 	snprintf(dir_name, sizeof(dir_name), "port%d", port->port);
1739 	parent = debugfs_lookup(dir_name, port->sw->debugfs_dir);
1740 	if (parent)
1741 		debugfs_lookup_and_remove("margining", parent);
1742 
1743 	kfree(port->usb4->margining);
1744 	port->usb4->margining = NULL;
1745 }
1746 
1747 static void margining_switch_init(struct tb_switch *sw)
1748 {
1749 	struct tb_port *upstream, *downstream;
1750 	struct tb_switch *parent_sw;
1751 	u64 route = tb_route(sw);
1752 
1753 	if (!route)
1754 		return;
1755 
1756 	upstream = tb_upstream_port(sw);
1757 	parent_sw = tb_switch_parent(sw);
1758 	downstream = tb_port_at(route, parent_sw);
1759 
1760 	margining_port_init(downstream);
1761 	margining_port_init(upstream);
1762 }
1763 
1764 static void margining_switch_remove(struct tb_switch *sw)
1765 {
1766 	struct tb_port *upstream, *downstream;
1767 	struct tb_switch *parent_sw;
1768 	u64 route = tb_route(sw);
1769 
1770 	if (!route)
1771 		return;
1772 
1773 	upstream = tb_upstream_port(sw);
1774 	parent_sw = tb_switch_parent(sw);
1775 	downstream = tb_port_at(route, parent_sw);
1776 
1777 	margining_port_remove(upstream);
1778 	margining_port_remove(downstream);
1779 }
1780 
1781 static void margining_xdomain_init(struct tb_xdomain *xd)
1782 {
1783 	struct tb_switch *parent_sw;
1784 	struct tb_port *downstream;
1785 
1786 	parent_sw = tb_xdomain_parent(xd);
1787 	downstream = tb_port_at(xd->route, parent_sw);
1788 
1789 	margining_port_init(downstream);
1790 }
1791 
1792 static void margining_xdomain_remove(struct tb_xdomain *xd)
1793 {
1794 	struct tb_switch *parent_sw;
1795 	struct tb_port *downstream;
1796 
1797 	parent_sw = tb_xdomain_parent(xd);
1798 	downstream = tb_port_at(xd->route, parent_sw);
1799 	margining_port_remove(downstream);
1800 }
1801 
1802 static void margining_retimer_init(struct tb_retimer *rt, struct dentry *debugfs_dir)
1803 {
1804 	rt->margining = margining_alloc(rt->port, &rt->dev,
1805 					USB4_SB_TARGET_RETIMER, rt->index,
1806 					debugfs_dir);
1807 }
1808 
1809 static void margining_retimer_remove(struct tb_retimer *rt)
1810 {
1811 	kfree(rt->margining);
1812 	rt->margining = NULL;
1813 }
1814 #else
1815 static inline void margining_switch_init(struct tb_switch *sw) { }
1816 static inline void margining_switch_remove(struct tb_switch *sw) { }
1817 static inline void margining_xdomain_init(struct tb_xdomain *xd) { }
1818 static inline void margining_xdomain_remove(struct tb_xdomain *xd) { }
1819 static inline void margining_retimer_init(struct tb_retimer *rt,
1820 					  struct dentry *debugfs_dir) { }
1821 static inline void margining_retimer_remove(struct tb_retimer *rt) { }
1822 #endif
1823 
1824 static int port_clear_all_counters(struct tb_port *port)
1825 {
1826 	u32 *buf;
1827 	int ret;
1828 
1829 	buf = kcalloc(COUNTER_SET_LEN * port->config.max_counters, sizeof(u32),
1830 		      GFP_KERNEL);
1831 	if (!buf)
1832 		return -ENOMEM;
1833 
1834 	ret = tb_port_write(port, buf, TB_CFG_COUNTERS, 0,
1835 			    COUNTER_SET_LEN * port->config.max_counters);
1836 	kfree(buf);
1837 
1838 	return ret;
1839 }
1840 
1841 static ssize_t counters_write(struct file *file, const char __user *user_buf,
1842 			      size_t count, loff_t *ppos)
1843 {
1844 	struct seq_file *s = file->private_data;
1845 	struct tb_port *port = s->private;
1846 	struct tb_switch *sw = port->sw;
1847 	struct tb *tb = port->sw->tb;
1848 	char *buf;
1849 	int ret;
1850 
1851 	buf = validate_and_copy_from_user(user_buf, &count);
1852 	if (IS_ERR(buf))
1853 		return PTR_ERR(buf);
1854 
1855 	pm_runtime_get_sync(&sw->dev);
1856 
1857 	if (mutex_lock_interruptible(&tb->lock)) {
1858 		ret = -ERESTARTSYS;
1859 		goto out;
1860 	}
1861 
1862 	/* If written delimiter only, clear all counters in one shot */
1863 	if (buf[0] == '\n') {
1864 		ret = port_clear_all_counters(port);
1865 	} else  {
1866 		char *line = buf;
1867 		u32 val, offset;
1868 
1869 		ret = -EINVAL;
1870 		while (parse_line(&line, &offset, &val, 1, 4)) {
1871 			ret = tb_port_write(port, &val, TB_CFG_COUNTERS,
1872 					    offset, 1);
1873 			if (ret)
1874 				break;
1875 		}
1876 	}
1877 
1878 	mutex_unlock(&tb->lock);
1879 
1880 out:
1881 	pm_runtime_mark_last_busy(&sw->dev);
1882 	pm_runtime_put_autosuspend(&sw->dev);
1883 	free_page((unsigned long)buf);
1884 
1885 	return ret < 0 ? ret : count;
1886 }
1887 
1888 static void cap_show_by_dw(struct seq_file *s, struct tb_switch *sw,
1889 			   struct tb_port *port, unsigned int cap,
1890 			   unsigned int offset, u8 cap_id, u8 vsec_id,
1891 			   int dwords)
1892 {
1893 	int i, ret;
1894 	u32 data;
1895 
1896 	for (i = 0; i < dwords; i++) {
1897 		if (port)
1898 			ret = tb_port_read(port, &data, TB_CFG_PORT, cap + offset + i, 1);
1899 		else
1900 			ret = tb_sw_read(sw, &data, TB_CFG_SWITCH, cap + offset + i, 1);
1901 		if (ret) {
1902 			seq_printf(s, "0x%04x <not accessible>\n", cap + offset + i);
1903 			continue;
1904 		}
1905 
1906 		seq_printf(s, "0x%04x %4d 0x%02x 0x%02x 0x%08x\n", cap + offset + i,
1907 			   offset + i, cap_id, vsec_id, data);
1908 	}
1909 }
1910 
1911 static void cap_show(struct seq_file *s, struct tb_switch *sw,
1912 		     struct tb_port *port, unsigned int cap, u8 cap_id,
1913 		     u8 vsec_id, int length)
1914 {
1915 	int ret, offset = 0;
1916 
1917 	while (length > 0) {
1918 		int i, dwords = min(length, TB_MAX_CONFIG_RW_LENGTH);
1919 		u32 data[TB_MAX_CONFIG_RW_LENGTH];
1920 
1921 		if (port)
1922 			ret = tb_port_read(port, data, TB_CFG_PORT, cap + offset,
1923 					   dwords);
1924 		else
1925 			ret = tb_sw_read(sw, data, TB_CFG_SWITCH, cap + offset, dwords);
1926 		if (ret) {
1927 			cap_show_by_dw(s, sw, port, cap, offset, cap_id, vsec_id, length);
1928 			return;
1929 		}
1930 
1931 		for (i = 0; i < dwords; i++) {
1932 			seq_printf(s, "0x%04x %4d 0x%02x 0x%02x 0x%08x\n",
1933 				   cap + offset + i, offset + i,
1934 				   cap_id, vsec_id, data[i]);
1935 		}
1936 
1937 		length -= dwords;
1938 		offset += dwords;
1939 	}
1940 }
1941 
1942 static void port_cap_show(struct tb_port *port, struct seq_file *s,
1943 			  unsigned int cap)
1944 {
1945 	struct tb_cap_any header;
1946 	u8 vsec_id = 0;
1947 	size_t length;
1948 	int ret;
1949 
1950 	ret = tb_port_read(port, &header, TB_CFG_PORT, cap, 1);
1951 	if (ret) {
1952 		seq_printf(s, "0x%04x <capability read failed>\n", cap);
1953 		return;
1954 	}
1955 
1956 	switch (header.basic.cap) {
1957 	case TB_PORT_CAP_PHY:
1958 		length = PORT_CAP_LANE_LEN;
1959 		break;
1960 
1961 	case TB_PORT_CAP_TIME1:
1962 		if (usb4_switch_version(port->sw) < 2)
1963 			length = PORT_CAP_TMU_V1_LEN;
1964 		else
1965 			length = PORT_CAP_TMU_V2_LEN;
1966 		break;
1967 
1968 	case TB_PORT_CAP_POWER:
1969 		length = PORT_CAP_POWER_LEN;
1970 		break;
1971 
1972 	case TB_PORT_CAP_ADAP:
1973 		if (tb_port_is_pcie_down(port) || tb_port_is_pcie_up(port)) {
1974 			if (usb4_switch_version(port->sw) < 2)
1975 				length = PORT_CAP_V1_PCIE_LEN;
1976 			else
1977 				length = PORT_CAP_V2_PCIE_LEN;
1978 		} else if (tb_port_is_dpin(port)) {
1979 			if (usb4_switch_version(port->sw) < 2)
1980 				length = PORT_CAP_DP_V1_LEN;
1981 			else
1982 				length = PORT_CAP_DP_V2_LEN;
1983 		} else if (tb_port_is_dpout(port)) {
1984 			length = PORT_CAP_DP_V1_LEN;
1985 		} else if (tb_port_is_usb3_down(port) ||
1986 			   tb_port_is_usb3_up(port)) {
1987 			length = PORT_CAP_USB3_LEN;
1988 		} else {
1989 			seq_printf(s, "0x%04x <unsupported capability 0x%02x>\n",
1990 				   cap, header.basic.cap);
1991 			return;
1992 		}
1993 		break;
1994 
1995 	case TB_PORT_CAP_VSE:
1996 		if (!header.extended_short.length) {
1997 			ret = tb_port_read(port, (u32 *)&header + 1, TB_CFG_PORT,
1998 					   cap + 1, 1);
1999 			if (ret) {
2000 				seq_printf(s, "0x%04x <capability read failed>\n",
2001 					   cap + 1);
2002 				return;
2003 			}
2004 			length = header.extended_long.length;
2005 			vsec_id = header.extended_short.vsec_id;
2006 		} else {
2007 			length = header.extended_short.length;
2008 			vsec_id = header.extended_short.vsec_id;
2009 		}
2010 		break;
2011 
2012 	case TB_PORT_CAP_USB4:
2013 		length = PORT_CAP_USB4_LEN;
2014 		break;
2015 
2016 	default:
2017 		seq_printf(s, "0x%04x <unsupported capability 0x%02x>\n",
2018 			   cap, header.basic.cap);
2019 		return;
2020 	}
2021 
2022 	cap_show(s, NULL, port, cap, header.basic.cap, vsec_id, length);
2023 }
2024 
2025 static void port_caps_show(struct tb_port *port, struct seq_file *s)
2026 {
2027 	int cap;
2028 
2029 	cap = tb_port_next_cap(port, 0);
2030 	while (cap > 0) {
2031 		port_cap_show(port, s, cap);
2032 		cap = tb_port_next_cap(port, cap);
2033 	}
2034 }
2035 
2036 static int port_basic_regs_show(struct tb_port *port, struct seq_file *s)
2037 {
2038 	u32 data[PORT_CAP_BASIC_LEN];
2039 	int ret, i;
2040 
2041 	ret = tb_port_read(port, data, TB_CFG_PORT, 0, ARRAY_SIZE(data));
2042 	if (ret)
2043 		return ret;
2044 
2045 	for (i = 0; i < ARRAY_SIZE(data); i++)
2046 		seq_printf(s, "0x%04x %4d 0x00 0x00 0x%08x\n", i, i, data[i]);
2047 
2048 	return 0;
2049 }
2050 
2051 static int port_regs_show(struct seq_file *s, void *not_used)
2052 {
2053 	struct tb_port *port = s->private;
2054 	struct tb_switch *sw = port->sw;
2055 	struct tb *tb = sw->tb;
2056 	int ret;
2057 
2058 	pm_runtime_get_sync(&sw->dev);
2059 
2060 	if (mutex_lock_interruptible(&tb->lock)) {
2061 		ret = -ERESTARTSYS;
2062 		goto out_rpm_put;
2063 	}
2064 
2065 	seq_puts(s, "# offset relative_offset cap_id vs_cap_id value\n");
2066 
2067 	ret = port_basic_regs_show(port, s);
2068 	if (ret)
2069 		goto out_unlock;
2070 
2071 	port_caps_show(port, s);
2072 
2073 out_unlock:
2074 	mutex_unlock(&tb->lock);
2075 out_rpm_put:
2076 	pm_runtime_mark_last_busy(&sw->dev);
2077 	pm_runtime_put_autosuspend(&sw->dev);
2078 
2079 	return ret;
2080 }
2081 DEBUGFS_ATTR_RW(port_regs);
2082 
2083 static void switch_cap_show(struct tb_switch *sw, struct seq_file *s,
2084 			    unsigned int cap)
2085 {
2086 	struct tb_cap_any header;
2087 	int ret, length;
2088 	u8 vsec_id = 0;
2089 
2090 	ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, cap, 1);
2091 	if (ret) {
2092 		seq_printf(s, "0x%04x <capability read failed>\n", cap);
2093 		return;
2094 	}
2095 
2096 	if (header.basic.cap == TB_SWITCH_CAP_VSE) {
2097 		if (!header.extended_short.length) {
2098 			ret = tb_sw_read(sw, (u32 *)&header + 1, TB_CFG_SWITCH,
2099 					 cap + 1, 1);
2100 			if (ret) {
2101 				seq_printf(s, "0x%04x <capability read failed>\n",
2102 					   cap + 1);
2103 				return;
2104 			}
2105 			length = header.extended_long.length;
2106 		} else {
2107 			length = header.extended_short.length;
2108 		}
2109 		vsec_id = header.extended_short.vsec_id;
2110 	} else {
2111 		if (header.basic.cap == TB_SWITCH_CAP_TMU) {
2112 			length = SWITCH_CAP_TMU_LEN;
2113 		} else  {
2114 			seq_printf(s, "0x%04x <unknown capability 0x%02x>\n",
2115 				   cap, header.basic.cap);
2116 			return;
2117 		}
2118 	}
2119 
2120 	cap_show(s, sw, NULL, cap, header.basic.cap, vsec_id, length);
2121 }
2122 
2123 static void switch_caps_show(struct tb_switch *sw, struct seq_file *s)
2124 {
2125 	int cap;
2126 
2127 	cap = tb_switch_next_cap(sw, 0);
2128 	while (cap > 0) {
2129 		switch_cap_show(sw, s, cap);
2130 		cap = tb_switch_next_cap(sw, cap);
2131 	}
2132 }
2133 
2134 static int switch_basic_regs_show(struct tb_switch *sw, struct seq_file *s)
2135 {
2136 	u32 data[SWITCH_CAP_BASIC_LEN];
2137 	size_t dwords;
2138 	int ret, i;
2139 
2140 	/* Only USB4 has the additional registers */
2141 	if (tb_switch_is_usb4(sw))
2142 		dwords = ARRAY_SIZE(data);
2143 	else
2144 		dwords = 5;
2145 
2146 	ret = tb_sw_read(sw, data, TB_CFG_SWITCH, 0, dwords);
2147 	if (ret)
2148 		return ret;
2149 
2150 	for (i = 0; i < dwords; i++)
2151 		seq_printf(s, "0x%04x %4d 0x00 0x00 0x%08x\n", i, i, data[i]);
2152 
2153 	return 0;
2154 }
2155 
2156 static int switch_regs_show(struct seq_file *s, void *not_used)
2157 {
2158 	struct tb_switch *sw = s->private;
2159 	struct tb *tb = sw->tb;
2160 	int ret;
2161 
2162 	pm_runtime_get_sync(&sw->dev);
2163 
2164 	if (mutex_lock_interruptible(&tb->lock)) {
2165 		ret = -ERESTARTSYS;
2166 		goto out_rpm_put;
2167 	}
2168 
2169 	seq_puts(s, "# offset relative_offset cap_id vs_cap_id value\n");
2170 
2171 	ret = switch_basic_regs_show(sw, s);
2172 	if (ret)
2173 		goto out_unlock;
2174 
2175 	switch_caps_show(sw, s);
2176 
2177 out_unlock:
2178 	mutex_unlock(&tb->lock);
2179 out_rpm_put:
2180 	pm_runtime_mark_last_busy(&sw->dev);
2181 	pm_runtime_put_autosuspend(&sw->dev);
2182 
2183 	return ret;
2184 }
2185 DEBUGFS_ATTR_RW(switch_regs);
2186 
2187 static int path_show_one(struct tb_port *port, struct seq_file *s, int hopid)
2188 {
2189 	u32 data[PATH_LEN];
2190 	int ret, i;
2191 
2192 	ret = tb_port_read(port, data, TB_CFG_HOPS, hopid * PATH_LEN,
2193 			   ARRAY_SIZE(data));
2194 	if (ret) {
2195 		seq_printf(s, "0x%04x <not accessible>\n", hopid * PATH_LEN);
2196 		return ret;
2197 	}
2198 
2199 	for (i = 0; i < ARRAY_SIZE(data); i++) {
2200 		seq_printf(s, "0x%04x %4d 0x%02x 0x%08x\n",
2201 			   hopid * PATH_LEN + i, i, hopid, data[i]);
2202 	}
2203 
2204 	return 0;
2205 }
2206 
2207 static int path_show(struct seq_file *s, void *not_used)
2208 {
2209 	struct tb_port *port = s->private;
2210 	struct tb_switch *sw = port->sw;
2211 	struct tb *tb = sw->tb;
2212 	int start, i, ret = 0;
2213 
2214 	pm_runtime_get_sync(&sw->dev);
2215 
2216 	if (mutex_lock_interruptible(&tb->lock)) {
2217 		ret = -ERESTARTSYS;
2218 		goto out_rpm_put;
2219 	}
2220 
2221 	seq_puts(s, "# offset relative_offset in_hop_id value\n");
2222 
2223 	/* NHI and lane adapters have entry for path 0 */
2224 	if (tb_port_is_null(port) || tb_port_is_nhi(port)) {
2225 		ret = path_show_one(port, s, 0);
2226 		if (ret)
2227 			goto out_unlock;
2228 	}
2229 
2230 	start = tb_port_is_nhi(port) ? 1 : TB_PATH_MIN_HOPID;
2231 
2232 	for (i = start; i <= port->config.max_in_hop_id; i++) {
2233 		ret = path_show_one(port, s, i);
2234 		if (ret)
2235 			break;
2236 	}
2237 
2238 out_unlock:
2239 	mutex_unlock(&tb->lock);
2240 out_rpm_put:
2241 	pm_runtime_mark_last_busy(&sw->dev);
2242 	pm_runtime_put_autosuspend(&sw->dev);
2243 
2244 	return ret;
2245 }
2246 DEBUGFS_ATTR_RO(path);
2247 
2248 static int counter_set_regs_show(struct tb_port *port, struct seq_file *s,
2249 				 int counter)
2250 {
2251 	u32 data[COUNTER_SET_LEN];
2252 	int ret, i;
2253 
2254 	ret = tb_port_read(port, data, TB_CFG_COUNTERS,
2255 			   counter * COUNTER_SET_LEN, ARRAY_SIZE(data));
2256 	if (ret) {
2257 		seq_printf(s, "0x%04x <not accessible>\n",
2258 			   counter * COUNTER_SET_LEN);
2259 		return ret;
2260 	}
2261 
2262 	for (i = 0; i < ARRAY_SIZE(data); i++) {
2263 		seq_printf(s, "0x%04x %4d 0x%02x 0x%08x\n",
2264 			   counter * COUNTER_SET_LEN + i, i, counter, data[i]);
2265 	}
2266 
2267 	return 0;
2268 }
2269 
2270 static int counters_show(struct seq_file *s, void *not_used)
2271 {
2272 	struct tb_port *port = s->private;
2273 	struct tb_switch *sw = port->sw;
2274 	struct tb *tb = sw->tb;
2275 	int i, ret = 0;
2276 
2277 	pm_runtime_get_sync(&sw->dev);
2278 
2279 	if (mutex_lock_interruptible(&tb->lock)) {
2280 		ret = -ERESTARTSYS;
2281 		goto out;
2282 	}
2283 
2284 	seq_puts(s, "# offset relative_offset counter_id value\n");
2285 
2286 	for (i = 0; i < port->config.max_counters; i++) {
2287 		ret = counter_set_regs_show(port, s, i);
2288 		if (ret)
2289 			break;
2290 	}
2291 
2292 	mutex_unlock(&tb->lock);
2293 
2294 out:
2295 	pm_runtime_mark_last_busy(&sw->dev);
2296 	pm_runtime_put_autosuspend(&sw->dev);
2297 
2298 	return ret;
2299 }
2300 DEBUGFS_ATTR_RW(counters);
2301 
2302 static int sb_regs_show(struct tb_port *port, const struct sb_reg *sb_regs,
2303 			size_t size, enum usb4_sb_target target, u8 index,
2304 			struct seq_file *s)
2305 {
2306 	int ret, i;
2307 
2308 	seq_puts(s, "# register value\n");
2309 
2310 	for (i = 0; i < size; i++) {
2311 		const struct sb_reg *regs = &sb_regs[i];
2312 		u8 data[64];
2313 		int j;
2314 
2315 		memset(data, 0, sizeof(data));
2316 		ret = usb4_port_sb_read(port, target, index, regs->reg, data,
2317 					regs->size);
2318 		if (ret)
2319 			return ret;
2320 
2321 		seq_printf(s, "0x%02x", regs->reg);
2322 		for (j = 0; j < regs->size; j++)
2323 			seq_printf(s, " 0x%02x", data[j]);
2324 		seq_puts(s, "\n");
2325 	}
2326 
2327 	return 0;
2328 }
2329 
2330 static int port_sb_regs_show(struct seq_file *s, void *not_used)
2331 {
2332 	struct tb_port *port = s->private;
2333 	struct tb_switch *sw = port->sw;
2334 	struct tb *tb = sw->tb;
2335 	int ret;
2336 
2337 	pm_runtime_get_sync(&sw->dev);
2338 
2339 	if (mutex_lock_interruptible(&tb->lock)) {
2340 		ret = -ERESTARTSYS;
2341 		goto out_rpm_put;
2342 	}
2343 
2344 	ret = sb_regs_show(port, port_sb_regs, ARRAY_SIZE(port_sb_regs),
2345 			   USB4_SB_TARGET_ROUTER, 0, s);
2346 
2347 	mutex_unlock(&tb->lock);
2348 out_rpm_put:
2349 	pm_runtime_mark_last_busy(&sw->dev);
2350 	pm_runtime_put_autosuspend(&sw->dev);
2351 
2352 	return ret;
2353 }
2354 DEBUGFS_ATTR_RW(port_sb_regs);
2355 
2356 /**
2357  * tb_switch_debugfs_init() - Add debugfs entries for router
2358  * @sw: Pointer to the router
2359  *
2360  * Adds debugfs directories and files for given router.
2361  */
2362 void tb_switch_debugfs_init(struct tb_switch *sw)
2363 {
2364 	struct dentry *debugfs_dir;
2365 	struct tb_port *port;
2366 
2367 	debugfs_dir = debugfs_create_dir(dev_name(&sw->dev), tb_debugfs_root);
2368 	sw->debugfs_dir = debugfs_dir;
2369 	debugfs_create_file("regs", DEBUGFS_MODE, debugfs_dir, sw,
2370 			    &switch_regs_fops);
2371 
2372 	tb_switch_for_each_port(sw, port) {
2373 		struct dentry *debugfs_dir;
2374 		char dir_name[10];
2375 
2376 		if (port->disabled)
2377 			continue;
2378 		if (port->config.type == TB_TYPE_INACTIVE)
2379 			continue;
2380 
2381 		snprintf(dir_name, sizeof(dir_name), "port%d", port->port);
2382 		debugfs_dir = debugfs_create_dir(dir_name, sw->debugfs_dir);
2383 		debugfs_create_file("regs", DEBUGFS_MODE, debugfs_dir,
2384 				    port, &port_regs_fops);
2385 		debugfs_create_file("path", 0400, debugfs_dir, port,
2386 				    &path_fops);
2387 		if (port->config.counters_support)
2388 			debugfs_create_file("counters", 0600, debugfs_dir, port,
2389 					    &counters_fops);
2390 		if (port->usb4)
2391 			debugfs_create_file("sb_regs", DEBUGFS_MODE, debugfs_dir,
2392 					    port, &port_sb_regs_fops);
2393 	}
2394 
2395 	margining_switch_init(sw);
2396 }
2397 
2398 /**
2399  * tb_switch_debugfs_remove() - Remove all router debugfs entries
2400  * @sw: Pointer to the router
2401  *
2402  * Removes all previously added debugfs entries under this router.
2403  */
2404 void tb_switch_debugfs_remove(struct tb_switch *sw)
2405 {
2406 	margining_switch_remove(sw);
2407 	debugfs_remove_recursive(sw->debugfs_dir);
2408 }
2409 
2410 void tb_xdomain_debugfs_init(struct tb_xdomain *xd)
2411 {
2412 	margining_xdomain_init(xd);
2413 }
2414 
2415 void tb_xdomain_debugfs_remove(struct tb_xdomain *xd)
2416 {
2417 	margining_xdomain_remove(xd);
2418 }
2419 
2420 /**
2421  * tb_service_debugfs_init() - Add debugfs directory for service
2422  * @svc: Thunderbolt service pointer
2423  *
2424  * Adds debugfs directory for service.
2425  */
2426 void tb_service_debugfs_init(struct tb_service *svc)
2427 {
2428 	svc->debugfs_dir = debugfs_create_dir(dev_name(&svc->dev),
2429 					      tb_debugfs_root);
2430 }
2431 
2432 /**
2433  * tb_service_debugfs_remove() - Remove service debugfs directory
2434  * @svc: Thunderbolt service pointer
2435  *
2436  * Removes the previously created debugfs directory for @svc.
2437  */
2438 void tb_service_debugfs_remove(struct tb_service *svc)
2439 {
2440 	debugfs_remove_recursive(svc->debugfs_dir);
2441 	svc->debugfs_dir = NULL;
2442 }
2443 
2444 static int retimer_sb_regs_show(struct seq_file *s, void *not_used)
2445 {
2446 	struct tb_retimer *rt = s->private;
2447 	struct tb *tb = rt->tb;
2448 	int ret;
2449 
2450 	pm_runtime_get_sync(&rt->dev);
2451 
2452 	if (mutex_lock_interruptible(&tb->lock)) {
2453 		ret = -ERESTARTSYS;
2454 		goto out_rpm_put;
2455 	}
2456 
2457 	ret = sb_regs_show(rt->port, retimer_sb_regs, ARRAY_SIZE(retimer_sb_regs),
2458 			   USB4_SB_TARGET_RETIMER, rt->index, s);
2459 
2460 	mutex_unlock(&tb->lock);
2461 out_rpm_put:
2462 	pm_runtime_mark_last_busy(&rt->dev);
2463 	pm_runtime_put_autosuspend(&rt->dev);
2464 
2465 	return ret;
2466 }
2467 DEBUGFS_ATTR_RW(retimer_sb_regs);
2468 
2469 /**
2470  * tb_retimer_debugfs_init() - Add debugfs directory for retimer
2471  * @rt: Pointer to retimer structure
2472  *
2473  * Adds and populates retimer debugfs directory.
2474  */
2475 void tb_retimer_debugfs_init(struct tb_retimer *rt)
2476 {
2477 	struct dentry *debugfs_dir;
2478 
2479 	debugfs_dir = debugfs_create_dir(dev_name(&rt->dev), tb_debugfs_root);
2480 	debugfs_create_file("sb_regs", DEBUGFS_MODE, debugfs_dir, rt,
2481 			    &retimer_sb_regs_fops);
2482 	margining_retimer_init(rt, debugfs_dir);
2483 }
2484 
2485 /**
2486  * tb_retimer_debugfs_remove() - Remove retimer debugfs directory
2487  * @rt: Pointer to retimer structure
2488  *
2489  * Removes the retimer debugfs directory along with its contents.
2490  */
2491 void tb_retimer_debugfs_remove(struct tb_retimer *rt)
2492 {
2493 	debugfs_lookup_and_remove(dev_name(&rt->dev), tb_debugfs_root);
2494 	margining_retimer_remove(rt);
2495 }
2496 
2497 void tb_debugfs_init(void)
2498 {
2499 	tb_debugfs_root = debugfs_create_dir("thunderbolt", NULL);
2500 }
2501 
2502 void tb_debugfs_exit(void)
2503 {
2504 	debugfs_remove_recursive(tb_debugfs_root);
2505 }
2506