xref: /linux-6.15/drivers/thunderbolt/retimer.c (revision f1138fda) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Thunderbolt/USB4 retimer support.
4  *
5  * Copyright (C) 2020, Intel Corporation
6  * Authors: Kranthi Kuntala <[email protected]>
7  *	    Mika Westerberg <[email protected]>
8  */
9 
10 #include <linux/delay.h>
11 #include <linux/pm_runtime.h>
12 #include <linux/sched/signal.h>
13 
14 #include "sb_regs.h"
15 #include "tb.h"
16 
17 #define TB_MAX_RETIMER_INDEX	6
18 
19 /**
20  * tb_retimer_nvm_read() - Read contents of retimer NVM
21  * @rt: Retimer device
22  * @address: NVM address (in bytes) to start reading
23  * @buf: Data read from NVM is stored here
24  * @size: Number of bytes to read
25  *
26  * Reads retimer NVM and copies the contents to @buf. Returns %0 if the
27  * read was successful and negative errno in case of failure.
28  */
29 int tb_retimer_nvm_read(struct tb_retimer *rt, unsigned int address, void *buf,
30 			size_t size)
31 {
32 	return usb4_port_retimer_nvm_read(rt->port, rt->index, address, buf, size);
33 }
34 
35 static int nvm_read(void *priv, unsigned int offset, void *val, size_t bytes)
36 {
37 	struct tb_nvm *nvm = priv;
38 	struct tb_retimer *rt = tb_to_retimer(nvm->dev);
39 	int ret;
40 
41 	pm_runtime_get_sync(&rt->dev);
42 
43 	if (!mutex_trylock(&rt->tb->lock)) {
44 		ret = restart_syscall();
45 		goto out;
46 	}
47 
48 	ret = tb_retimer_nvm_read(rt, offset, val, bytes);
49 	mutex_unlock(&rt->tb->lock);
50 
51 out:
52 	pm_runtime_mark_last_busy(&rt->dev);
53 	pm_runtime_put_autosuspend(&rt->dev);
54 
55 	return ret;
56 }
57 
58 static int nvm_write(void *priv, unsigned int offset, void *val, size_t bytes)
59 {
60 	struct tb_nvm *nvm = priv;
61 	struct tb_retimer *rt = tb_to_retimer(nvm->dev);
62 	int ret = 0;
63 
64 	if (!mutex_trylock(&rt->tb->lock))
65 		return restart_syscall();
66 
67 	ret = tb_nvm_write_buf(nvm, offset, val, bytes);
68 	mutex_unlock(&rt->tb->lock);
69 
70 	return ret;
71 }
72 
73 static int tb_retimer_nvm_add(struct tb_retimer *rt)
74 {
75 	struct tb_nvm *nvm;
76 	int ret;
77 
78 	nvm = tb_nvm_alloc(&rt->dev);
79 	if (IS_ERR(nvm)) {
80 		ret = PTR_ERR(nvm) == -EOPNOTSUPP ? 0 : PTR_ERR(nvm);
81 		goto err_nvm;
82 	}
83 
84 	ret = tb_nvm_read_version(nvm);
85 	if (ret)
86 		goto err_nvm;
87 
88 	ret = tb_nvm_add_active(nvm, nvm_read);
89 	if (ret)
90 		goto err_nvm;
91 
92 	ret = tb_nvm_add_non_active(nvm, nvm_write);
93 	if (ret)
94 		goto err_nvm;
95 
96 	rt->nvm = nvm;
97 	return 0;
98 
99 err_nvm:
100 	dev_dbg(&rt->dev, "NVM upgrade disabled\n");
101 	if (!IS_ERR(nvm))
102 		tb_nvm_free(nvm);
103 
104 	return ret;
105 }
106 
107 static int tb_retimer_nvm_validate_and_write(struct tb_retimer *rt)
108 {
109 	unsigned int image_size;
110 	const u8 *buf;
111 	int ret;
112 
113 	ret = tb_nvm_validate(rt->nvm);
114 	if (ret)
115 		return ret;
116 
117 	buf = rt->nvm->buf_data_start;
118 	image_size = rt->nvm->buf_data_size;
119 
120 	ret = usb4_port_retimer_nvm_write(rt->port, rt->index, 0, buf,
121 					 image_size);
122 	if (ret)
123 		return ret;
124 
125 	rt->nvm->flushed = true;
126 	return 0;
127 }
128 
129 static int tb_retimer_nvm_authenticate(struct tb_retimer *rt, bool auth_only)
130 {
131 	u32 status;
132 	int ret;
133 
134 	if (auth_only) {
135 		ret = usb4_port_retimer_nvm_set_offset(rt->port, rt->index, 0);
136 		if (ret)
137 			return ret;
138 	}
139 
140 	ret = usb4_port_retimer_nvm_authenticate(rt->port, rt->index);
141 	if (ret)
142 		return ret;
143 
144 	usleep_range(100, 150);
145 
146 	/*
147 	 * Check the status now if we still can access the retimer. It
148 	 * is expected that the below fails.
149 	 */
150 	ret = usb4_port_retimer_nvm_authenticate_status(rt->port, rt->index,
151 							&status);
152 	if (!ret) {
153 		rt->auth_status = status;
154 		return status ? -EINVAL : 0;
155 	}
156 
157 	return 0;
158 }
159 
160 static ssize_t device_show(struct device *dev, struct device_attribute *attr,
161 			   char *buf)
162 {
163 	struct tb_retimer *rt = tb_to_retimer(dev);
164 
165 	return sysfs_emit(buf, "%#x\n", rt->device);
166 }
167 static DEVICE_ATTR_RO(device);
168 
169 static ssize_t nvm_authenticate_show(struct device *dev,
170 	struct device_attribute *attr, char *buf)
171 {
172 	struct tb_retimer *rt = tb_to_retimer(dev);
173 	int ret;
174 
175 	if (!mutex_trylock(&rt->tb->lock))
176 		return restart_syscall();
177 
178 	if (!rt->nvm)
179 		ret = -EAGAIN;
180 	else if (rt->no_nvm_upgrade)
181 		ret = -EOPNOTSUPP;
182 	else
183 		ret = sysfs_emit(buf, "%#x\n", rt->auth_status);
184 
185 	mutex_unlock(&rt->tb->lock);
186 
187 	return ret;
188 }
189 
190 static void tb_retimer_set_inbound_sbtx(struct tb_port *port)
191 {
192 	int i;
193 
194 	for (i = 1; i <= TB_MAX_RETIMER_INDEX; i++)
195 		usb4_port_retimer_set_inbound_sbtx(port, i);
196 }
197 
198 static void tb_retimer_unset_inbound_sbtx(struct tb_port *port)
199 {
200 	int i;
201 
202 	for (i = TB_MAX_RETIMER_INDEX; i >= 1; i--)
203 		usb4_port_retimer_unset_inbound_sbtx(port, i);
204 }
205 
206 static ssize_t nvm_authenticate_store(struct device *dev,
207 	struct device_attribute *attr, const char *buf, size_t count)
208 {
209 	struct tb_retimer *rt = tb_to_retimer(dev);
210 	int val, ret;
211 
212 	pm_runtime_get_sync(&rt->dev);
213 
214 	if (!mutex_trylock(&rt->tb->lock)) {
215 		ret = restart_syscall();
216 		goto exit_rpm;
217 	}
218 
219 	if (!rt->nvm) {
220 		ret = -EAGAIN;
221 		goto exit_unlock;
222 	}
223 
224 	ret = kstrtoint(buf, 10, &val);
225 	if (ret)
226 		goto exit_unlock;
227 
228 	/* Always clear status */
229 	rt->auth_status = 0;
230 
231 	if (val) {
232 		tb_retimer_set_inbound_sbtx(rt->port);
233 		if (val == AUTHENTICATE_ONLY) {
234 			ret = tb_retimer_nvm_authenticate(rt, true);
235 		} else {
236 			if (!rt->nvm->flushed) {
237 				if (!rt->nvm->buf) {
238 					ret = -EINVAL;
239 					goto exit_unlock;
240 				}
241 
242 				ret = tb_retimer_nvm_validate_and_write(rt);
243 				if (ret || val == WRITE_ONLY)
244 					goto exit_unlock;
245 			}
246 			if (val == WRITE_AND_AUTHENTICATE)
247 				ret = tb_retimer_nvm_authenticate(rt, false);
248 		}
249 	}
250 
251 exit_unlock:
252 	tb_retimer_unset_inbound_sbtx(rt->port);
253 	mutex_unlock(&rt->tb->lock);
254 exit_rpm:
255 	pm_runtime_mark_last_busy(&rt->dev);
256 	pm_runtime_put_autosuspend(&rt->dev);
257 
258 	if (ret)
259 		return ret;
260 	return count;
261 }
262 static DEVICE_ATTR_RW(nvm_authenticate);
263 
264 static ssize_t nvm_version_show(struct device *dev,
265 				struct device_attribute *attr, char *buf)
266 {
267 	struct tb_retimer *rt = tb_to_retimer(dev);
268 	int ret;
269 
270 	if (!mutex_trylock(&rt->tb->lock))
271 		return restart_syscall();
272 
273 	if (!rt->nvm)
274 		ret = -EAGAIN;
275 	else
276 		ret = sysfs_emit(buf, "%x.%x\n", rt->nvm->major, rt->nvm->minor);
277 
278 	mutex_unlock(&rt->tb->lock);
279 	return ret;
280 }
281 static DEVICE_ATTR_RO(nvm_version);
282 
283 static ssize_t vendor_show(struct device *dev, struct device_attribute *attr,
284 			   char *buf)
285 {
286 	struct tb_retimer *rt = tb_to_retimer(dev);
287 
288 	return sysfs_emit(buf, "%#x\n", rt->vendor);
289 }
290 static DEVICE_ATTR_RO(vendor);
291 
292 static struct attribute *retimer_attrs[] = {
293 	&dev_attr_device.attr,
294 	&dev_attr_nvm_authenticate.attr,
295 	&dev_attr_nvm_version.attr,
296 	&dev_attr_vendor.attr,
297 	NULL
298 };
299 
300 static const struct attribute_group retimer_group = {
301 	.attrs = retimer_attrs,
302 };
303 
304 static const struct attribute_group *retimer_groups[] = {
305 	&retimer_group,
306 	NULL
307 };
308 
309 static void tb_retimer_release(struct device *dev)
310 {
311 	struct tb_retimer *rt = tb_to_retimer(dev);
312 
313 	kfree(rt);
314 }
315 
316 struct device_type tb_retimer_type = {
317 	.name = "thunderbolt_retimer",
318 	.groups = retimer_groups,
319 	.release = tb_retimer_release,
320 };
321 
322 static int tb_retimer_add(struct tb_port *port, u8 index, u32 auth_status)
323 {
324 	struct tb_retimer *rt;
325 	u32 vendor, device;
326 	int ret;
327 
328 	ret = usb4_port_retimer_read(port, index, USB4_SB_VENDOR_ID, &vendor,
329 				     sizeof(vendor));
330 	if (ret) {
331 		if (ret != -ENODEV)
332 			tb_port_warn(port, "failed read retimer VendorId: %d\n", ret);
333 		return ret;
334 	}
335 
336 	ret = usb4_port_retimer_read(port, index, USB4_SB_PRODUCT_ID, &device,
337 				     sizeof(device));
338 	if (ret) {
339 		if (ret != -ENODEV)
340 			tb_port_warn(port, "failed read retimer ProductId: %d\n", ret);
341 		return ret;
342 	}
343 
344 	/*
345 	 * Check that it supports NVM operations. If not then don't add
346 	 * the device at all.
347 	 */
348 	ret = usb4_port_retimer_nvm_sector_size(port, index);
349 	if (ret < 0)
350 		return ret;
351 
352 	rt = kzalloc(sizeof(*rt), GFP_KERNEL);
353 	if (!rt)
354 		return -ENOMEM;
355 
356 	rt->index = index;
357 	rt->vendor = vendor;
358 	rt->device = device;
359 	rt->auth_status = auth_status;
360 	rt->port = port;
361 	rt->tb = port->sw->tb;
362 
363 	rt->dev.parent = &port->usb4->dev;
364 	rt->dev.bus = &tb_bus_type;
365 	rt->dev.type = &tb_retimer_type;
366 	dev_set_name(&rt->dev, "%s:%u.%u", dev_name(&port->sw->dev),
367 		     port->port, index);
368 
369 	ret = device_register(&rt->dev);
370 	if (ret) {
371 		dev_err(&rt->dev, "failed to register retimer: %d\n", ret);
372 		put_device(&rt->dev);
373 		return ret;
374 	}
375 
376 	ret = tb_retimer_nvm_add(rt);
377 	if (ret) {
378 		dev_err(&rt->dev, "failed to add NVM devices: %d\n", ret);
379 		device_unregister(&rt->dev);
380 		return ret;
381 	}
382 
383 	dev_info(&rt->dev, "new retimer found, vendor=%#x device=%#x\n",
384 		 rt->vendor, rt->device);
385 
386 	pm_runtime_no_callbacks(&rt->dev);
387 	pm_runtime_set_active(&rt->dev);
388 	pm_runtime_enable(&rt->dev);
389 	pm_runtime_set_autosuspend_delay(&rt->dev, TB_AUTOSUSPEND_DELAY);
390 	pm_runtime_mark_last_busy(&rt->dev);
391 	pm_runtime_use_autosuspend(&rt->dev);
392 
393 	return 0;
394 }
395 
396 static void tb_retimer_remove(struct tb_retimer *rt)
397 {
398 	dev_info(&rt->dev, "retimer disconnected\n");
399 	tb_nvm_free(rt->nvm);
400 	device_unregister(&rt->dev);
401 }
402 
403 struct tb_retimer_lookup {
404 	const struct tb_port *port;
405 	u8 index;
406 };
407 
408 static int retimer_match(struct device *dev, void *data)
409 {
410 	const struct tb_retimer_lookup *lookup = data;
411 	struct tb_retimer *rt = tb_to_retimer(dev);
412 
413 	return rt && rt->port == lookup->port && rt->index == lookup->index;
414 }
415 
416 static struct tb_retimer *tb_port_find_retimer(struct tb_port *port, u8 index)
417 {
418 	struct tb_retimer_lookup lookup = { .port = port, .index = index };
419 	struct device *dev;
420 
421 	dev = device_find_child(&port->usb4->dev, &lookup, retimer_match);
422 	if (dev)
423 		return tb_to_retimer(dev);
424 
425 	return NULL;
426 }
427 
428 /**
429  * tb_retimer_scan() - Scan for on-board retimers under port
430  * @port: USB4 port to scan
431  * @add: If true also registers found retimers
432  *
433  * Brings the sideband into a state where retimers can be accessed.
434  * Then Tries to enumerate on-board retimers connected to @port. Found
435  * retimers are registered as children of @port if @add is set.  Does
436  * not scan for cable retimers for now.
437  */
438 int tb_retimer_scan(struct tb_port *port, bool add)
439 {
440 	u32 status[TB_MAX_RETIMER_INDEX + 1] = {};
441 	int ret, i, last_idx = 0;
442 
443 	/*
444 	 * Send broadcast RT to make sure retimer indices facing this
445 	 * port are set.
446 	 */
447 	ret = usb4_port_enumerate_retimers(port);
448 	if (ret)
449 		return ret;
450 
451 	/*
452 	 * Enable sideband channel for each retimer. We can do this
453 	 * regardless whether there is device connected or not.
454 	 */
455 	tb_retimer_set_inbound_sbtx(port);
456 
457 	/*
458 	 * Before doing anything else, read the authentication status.
459 	 * If the retimer has it set, store it for the new retimer
460 	 * device instance.
461 	 */
462 	for (i = 1; i <= TB_MAX_RETIMER_INDEX; i++)
463 		usb4_port_retimer_nvm_authenticate_status(port, i, &status[i]);
464 
465 	for (i = 1; i <= TB_MAX_RETIMER_INDEX; i++) {
466 		/*
467 		 * Last retimer is true only for the last on-board
468 		 * retimer (the one connected directly to the Type-C
469 		 * port).
470 		 */
471 		ret = usb4_port_retimer_is_last(port, i);
472 		if (ret > 0)
473 			last_idx = i;
474 		else if (ret < 0)
475 			break;
476 	}
477 
478 	tb_retimer_unset_inbound_sbtx(port);
479 
480 	if (!last_idx)
481 		return 0;
482 
483 	/* Add on-board retimers if they do not exist already */
484 	ret = 0;
485 	for (i = 1; i <= last_idx; i++) {
486 		struct tb_retimer *rt;
487 
488 		rt = tb_port_find_retimer(port, i);
489 		if (rt) {
490 			put_device(&rt->dev);
491 		} else if (add) {
492 			ret = tb_retimer_add(port, i, status[i]);
493 			if (ret && ret != -EOPNOTSUPP)
494 				break;
495 		}
496 	}
497 
498 	return ret;
499 }
500 
501 static int remove_retimer(struct device *dev, void *data)
502 {
503 	struct tb_retimer *rt = tb_to_retimer(dev);
504 	struct tb_port *port = data;
505 
506 	if (rt && rt->port == port)
507 		tb_retimer_remove(rt);
508 	return 0;
509 }
510 
511 /**
512  * tb_retimer_remove_all() - Remove all retimers under port
513  * @port: USB4 port whose retimers to remove
514  *
515  * This removes all previously added retimers under @port.
516  */
517 void tb_retimer_remove_all(struct tb_port *port)
518 {
519 	struct usb4_port *usb4;
520 
521 	usb4 = port->usb4;
522 	if (usb4)
523 		device_for_each_child_reverse(&usb4->dev, port,
524 					      remove_retimer);
525 }
526