1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Intel(R) Trace Hub driver core
4  *
5  * Copyright (C) 2014-2015 Intel Corporation.
6  */
7 
8 #define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
9 
10 #include <linux/types.h>
11 #include <linux/module.h>
12 #include <linux/device.h>
13 #include <linux/sysfs.h>
14 #include <linux/kdev_t.h>
15 #include <linux/debugfs.h>
16 #include <linux/idr.h>
17 #include <linux/pci.h>
18 #include <linux/pm_runtime.h>
19 #include <linux/dma-mapping.h>
20 
21 #include "intel_th.h"
22 #include "debug.h"
23 
24 static bool host_mode __read_mostly;
25 module_param(host_mode, bool, 0444);
26 
27 static DEFINE_IDA(intel_th_ida);
28 
29 static int intel_th_match(struct device *dev, struct device_driver *driver)
30 {
31 	struct intel_th_driver *thdrv = to_intel_th_driver(driver);
32 	struct intel_th_device *thdev = to_intel_th_device(dev);
33 
34 	if (thdev->type == INTEL_TH_SWITCH &&
35 	    (!thdrv->enable || !thdrv->disable))
36 		return 0;
37 
38 	return !strcmp(thdev->name, driver->name);
39 }
40 
41 static int intel_th_child_remove(struct device *dev, void *data)
42 {
43 	device_release_driver(dev);
44 
45 	return 0;
46 }
47 
48 static int intel_th_probe(struct device *dev)
49 {
50 	struct intel_th_driver *thdrv = to_intel_th_driver(dev->driver);
51 	struct intel_th_device *thdev = to_intel_th_device(dev);
52 	struct intel_th_driver *hubdrv;
53 	struct intel_th_device *hub = NULL;
54 	int ret;
55 
56 	if (thdev->type == INTEL_TH_SWITCH)
57 		hub = thdev;
58 	else if (dev->parent)
59 		hub = to_intel_th_device(dev->parent);
60 
61 	if (!hub || !hub->dev.driver)
62 		return -EPROBE_DEFER;
63 
64 	hubdrv = to_intel_th_driver(hub->dev.driver);
65 
66 	pm_runtime_set_active(dev);
67 	pm_runtime_no_callbacks(dev);
68 	pm_runtime_enable(dev);
69 
70 	ret = thdrv->probe(to_intel_th_device(dev));
71 	if (ret)
72 		goto out_pm;
73 
74 	if (thdrv->attr_group) {
75 		ret = sysfs_create_group(&thdev->dev.kobj, thdrv->attr_group);
76 		if (ret)
77 			goto out;
78 	}
79 
80 	if (thdev->type == INTEL_TH_OUTPUT &&
81 	    !intel_th_output_assigned(thdev))
82 		/* does not talk to hardware */
83 		ret = hubdrv->assign(hub, thdev);
84 
85 out:
86 	if (ret)
87 		thdrv->remove(thdev);
88 
89 out_pm:
90 	if (ret)
91 		pm_runtime_disable(dev);
92 
93 	return ret;
94 }
95 
96 static void intel_th_device_remove(struct intel_th_device *thdev);
97 
98 static int intel_th_remove(struct device *dev)
99 {
100 	struct intel_th_driver *thdrv = to_intel_th_driver(dev->driver);
101 	struct intel_th_device *thdev = to_intel_th_device(dev);
102 	struct intel_th_device *hub = to_intel_th_hub(thdev);
103 	int err;
104 
105 	if (thdev->type == INTEL_TH_SWITCH) {
106 		struct intel_th *th = to_intel_th(hub);
107 		int i, lowest;
108 
109 		/* disconnect outputs */
110 		err = device_for_each_child(dev, thdev, intel_th_child_remove);
111 		if (err)
112 			return err;
113 
114 		/*
115 		 * Remove outputs, that is, hub's children: they are created
116 		 * at hub's probe time by having the hub call
117 		 * intel_th_output_enable() for each of them.
118 		 */
119 		for (i = 0, lowest = -1; i < th->num_thdevs; i++) {
120 			/*
121 			 * Move the non-output devices from higher up the
122 			 * th->thdev[] array to lower positions to maintain
123 			 * a contiguous array.
124 			 */
125 			if (th->thdev[i]->type != INTEL_TH_OUTPUT) {
126 				if (lowest >= 0) {
127 					th->thdev[lowest] = th->thdev[i];
128 					th->thdev[i] = NULL;
129 					++lowest;
130 				}
131 
132 				continue;
133 			}
134 
135 			if (lowest == -1)
136 				lowest = i;
137 
138 			intel_th_device_remove(th->thdev[i]);
139 			th->thdev[i] = NULL;
140 		}
141 
142 		if (lowest >= 0)
143 			th->num_thdevs = lowest;
144 	}
145 
146 	if (thdrv->attr_group)
147 		sysfs_remove_group(&thdev->dev.kobj, thdrv->attr_group);
148 
149 	pm_runtime_get_sync(dev);
150 
151 	thdrv->remove(thdev);
152 
153 	if (intel_th_output_assigned(thdev)) {
154 		struct intel_th_driver *hubdrv =
155 			to_intel_th_driver(dev->parent->driver);
156 
157 		if (hub->dev.driver)
158 			/* does not talk to hardware */
159 			hubdrv->unassign(hub, thdev);
160 	}
161 
162 	pm_runtime_disable(dev);
163 	pm_runtime_set_active(dev);
164 	pm_runtime_enable(dev);
165 
166 	return 0;
167 }
168 
169 static struct bus_type intel_th_bus = {
170 	.name		= "intel_th",
171 	.match		= intel_th_match,
172 	.probe		= intel_th_probe,
173 	.remove		= intel_th_remove,
174 };
175 
176 static void intel_th_device_free(struct intel_th_device *thdev);
177 
178 static void intel_th_device_release(struct device *dev)
179 {
180 	intel_th_device_free(to_intel_th_device(dev));
181 }
182 
183 static struct device_type intel_th_source_device_type = {
184 	.name		= "intel_th_source_device",
185 	.release	= intel_th_device_release,
186 };
187 
188 static char *intel_th_output_devnode(struct device *dev, umode_t *mode,
189 				     kuid_t *uid, kgid_t *gid)
190 {
191 	struct intel_th_device *thdev = to_intel_th_device(dev);
192 	struct intel_th *th = to_intel_th(thdev);
193 	char *node;
194 
195 	if (thdev->id >= 0)
196 		node = kasprintf(GFP_KERNEL, "intel_th%d/%s%d", th->id,
197 				 thdev->name, thdev->id);
198 	else
199 		node = kasprintf(GFP_KERNEL, "intel_th%d/%s", th->id,
200 				 thdev->name);
201 
202 	return node;
203 }
204 
205 static ssize_t port_show(struct device *dev, struct device_attribute *attr,
206 			 char *buf)
207 {
208 	struct intel_th_device *thdev = to_intel_th_device(dev);
209 
210 	if (thdev->output.port >= 0)
211 		return scnprintf(buf, PAGE_SIZE, "%u\n", thdev->output.port);
212 
213 	return scnprintf(buf, PAGE_SIZE, "unassigned\n");
214 }
215 
216 static DEVICE_ATTR_RO(port);
217 
218 static int intel_th_output_activate(struct intel_th_device *thdev)
219 {
220 	struct intel_th_driver *thdrv =
221 		to_intel_th_driver_or_null(thdev->dev.driver);
222 	struct intel_th *th = to_intel_th(thdev);
223 	int ret = 0;
224 
225 	if (!thdrv)
226 		return -ENODEV;
227 
228 	if (!try_module_get(thdrv->driver.owner))
229 		return -ENODEV;
230 
231 	pm_runtime_get_sync(&thdev->dev);
232 
233 	if (th->activate)
234 		ret = th->activate(th);
235 	if (ret)
236 		goto fail_put;
237 
238 	if (thdrv->activate)
239 		ret = thdrv->activate(thdev);
240 	else
241 		intel_th_trace_enable(thdev);
242 
243 	if (ret)
244 		goto fail_deactivate;
245 
246 	return 0;
247 
248 fail_deactivate:
249 	if (th->deactivate)
250 		th->deactivate(th);
251 
252 fail_put:
253 	pm_runtime_put(&thdev->dev);
254 	module_put(thdrv->driver.owner);
255 
256 	return ret;
257 }
258 
259 static void intel_th_output_deactivate(struct intel_th_device *thdev)
260 {
261 	struct intel_th_driver *thdrv =
262 		to_intel_th_driver_or_null(thdev->dev.driver);
263 	struct intel_th *th = to_intel_th(thdev);
264 
265 	if (!thdrv)
266 		return;
267 
268 	if (thdrv->deactivate)
269 		thdrv->deactivate(thdev);
270 	else
271 		intel_th_trace_disable(thdev);
272 
273 	if (th->deactivate)
274 		th->deactivate(th);
275 
276 	pm_runtime_put(&thdev->dev);
277 	module_put(thdrv->driver.owner);
278 }
279 
280 static ssize_t active_show(struct device *dev, struct device_attribute *attr,
281 			   char *buf)
282 {
283 	struct intel_th_device *thdev = to_intel_th_device(dev);
284 
285 	return scnprintf(buf, PAGE_SIZE, "%d\n", thdev->output.active);
286 }
287 
288 static ssize_t active_store(struct device *dev, struct device_attribute *attr,
289 			    const char *buf, size_t size)
290 {
291 	struct intel_th_device *thdev = to_intel_th_device(dev);
292 	unsigned long val;
293 	int ret;
294 
295 	ret = kstrtoul(buf, 10, &val);
296 	if (ret)
297 		return ret;
298 
299 	if (!!val != thdev->output.active) {
300 		if (val)
301 			ret = intel_th_output_activate(thdev);
302 		else
303 			intel_th_output_deactivate(thdev);
304 	}
305 
306 	return ret ? ret : size;
307 }
308 
309 static DEVICE_ATTR_RW(active);
310 
311 static struct attribute *intel_th_output_attrs[] = {
312 	&dev_attr_port.attr,
313 	&dev_attr_active.attr,
314 	NULL,
315 };
316 
317 ATTRIBUTE_GROUPS(intel_th_output);
318 
319 static struct device_type intel_th_output_device_type = {
320 	.name		= "intel_th_output_device",
321 	.groups		= intel_th_output_groups,
322 	.release	= intel_th_device_release,
323 	.devnode	= intel_th_output_devnode,
324 };
325 
326 static struct device_type intel_th_switch_device_type = {
327 	.name		= "intel_th_switch_device",
328 	.release	= intel_th_device_release,
329 };
330 
331 static struct device_type *intel_th_device_type[] = {
332 	[INTEL_TH_SOURCE]	= &intel_th_source_device_type,
333 	[INTEL_TH_OUTPUT]	= &intel_th_output_device_type,
334 	[INTEL_TH_SWITCH]	= &intel_th_switch_device_type,
335 };
336 
337 int intel_th_driver_register(struct intel_th_driver *thdrv)
338 {
339 	if (!thdrv->probe || !thdrv->remove)
340 		return -EINVAL;
341 
342 	thdrv->driver.bus = &intel_th_bus;
343 
344 	return driver_register(&thdrv->driver);
345 }
346 EXPORT_SYMBOL_GPL(intel_th_driver_register);
347 
348 void intel_th_driver_unregister(struct intel_th_driver *thdrv)
349 {
350 	driver_unregister(&thdrv->driver);
351 }
352 EXPORT_SYMBOL_GPL(intel_th_driver_unregister);
353 
354 static struct intel_th_device *
355 intel_th_device_alloc(struct intel_th *th, unsigned int type, const char *name,
356 		      int id)
357 {
358 	struct device *parent;
359 	struct intel_th_device *thdev;
360 
361 	if (type == INTEL_TH_OUTPUT)
362 		parent = &th->hub->dev;
363 	else
364 		parent = th->dev;
365 
366 	thdev = kzalloc(sizeof(*thdev) + strlen(name) + 1, GFP_KERNEL);
367 	if (!thdev)
368 		return NULL;
369 
370 	thdev->id = id;
371 	thdev->type = type;
372 
373 	strcpy(thdev->name, name);
374 	device_initialize(&thdev->dev);
375 	thdev->dev.bus = &intel_th_bus;
376 	thdev->dev.type = intel_th_device_type[type];
377 	thdev->dev.parent = parent;
378 	thdev->dev.dma_mask = parent->dma_mask;
379 	thdev->dev.dma_parms = parent->dma_parms;
380 	dma_set_coherent_mask(&thdev->dev, parent->coherent_dma_mask);
381 	if (id >= 0)
382 		dev_set_name(&thdev->dev, "%d-%s%d", th->id, name, id);
383 	else
384 		dev_set_name(&thdev->dev, "%d-%s", th->id, name);
385 
386 	return thdev;
387 }
388 
389 static int intel_th_device_add_resources(struct intel_th_device *thdev,
390 					 struct resource *res, int nres)
391 {
392 	struct resource *r;
393 
394 	r = kmemdup(res, sizeof(*res) * nres, GFP_KERNEL);
395 	if (!r)
396 		return -ENOMEM;
397 
398 	thdev->resource = r;
399 	thdev->num_resources = nres;
400 
401 	return 0;
402 }
403 
404 static void intel_th_device_remove(struct intel_th_device *thdev)
405 {
406 	device_del(&thdev->dev);
407 	put_device(&thdev->dev);
408 }
409 
410 static void intel_th_device_free(struct intel_th_device *thdev)
411 {
412 	kfree(thdev->resource);
413 	kfree(thdev);
414 }
415 
416 /*
417  * Intel(R) Trace Hub subdevices
418  */
419 static const struct intel_th_subdevice {
420 	const char		*name;
421 	struct resource		res[3];
422 	unsigned		nres;
423 	unsigned		type;
424 	unsigned		otype;
425 	unsigned		scrpd;
426 	int			id;
427 } intel_th_subdevices[] = {
428 	{
429 		.nres	= 1,
430 		.res	= {
431 			{
432 				/* Handle TSCU from GTH driver */
433 				.start	= REG_GTH_OFFSET,
434 				.end	= REG_TSCU_OFFSET + REG_TSCU_LENGTH - 1,
435 				.flags	= IORESOURCE_MEM,
436 			},
437 		},
438 		.name	= "gth",
439 		.type	= INTEL_TH_SWITCH,
440 		.id	= -1,
441 	},
442 	{
443 		.nres	= 2,
444 		.res	= {
445 			{
446 				.start	= REG_MSU_OFFSET,
447 				.end	= REG_MSU_OFFSET + REG_MSU_LENGTH - 1,
448 				.flags	= IORESOURCE_MEM,
449 			},
450 			{
451 				.start	= BUF_MSU_OFFSET,
452 				.end	= BUF_MSU_OFFSET + BUF_MSU_LENGTH - 1,
453 				.flags	= IORESOURCE_MEM,
454 			},
455 		},
456 		.name	= "msc",
457 		.id	= 0,
458 		.type	= INTEL_TH_OUTPUT,
459 		.otype	= GTH_MSU,
460 		.scrpd	= SCRPD_MEM_IS_PRIM_DEST | SCRPD_MSC0_IS_ENABLED,
461 	},
462 	{
463 		.nres	= 2,
464 		.res	= {
465 			{
466 				.start	= REG_MSU_OFFSET,
467 				.end	= REG_MSU_OFFSET + REG_MSU_LENGTH - 1,
468 				.flags	= IORESOURCE_MEM,
469 			},
470 			{
471 				.start	= BUF_MSU_OFFSET,
472 				.end	= BUF_MSU_OFFSET + BUF_MSU_LENGTH - 1,
473 				.flags	= IORESOURCE_MEM,
474 			},
475 		},
476 		.name	= "msc",
477 		.id	= 1,
478 		.type	= INTEL_TH_OUTPUT,
479 		.otype	= GTH_MSU,
480 		.scrpd	= SCRPD_MEM_IS_PRIM_DEST | SCRPD_MSC1_IS_ENABLED,
481 	},
482 	{
483 		.nres	= 2,
484 		.res	= {
485 			{
486 				.start	= REG_STH_OFFSET,
487 				.end	= REG_STH_OFFSET + REG_STH_LENGTH - 1,
488 				.flags	= IORESOURCE_MEM,
489 			},
490 			{
491 				.start	= 1, /* use resource[1] */
492 				.end	= 0,
493 				.flags	= IORESOURCE_MEM,
494 			},
495 		},
496 		.id	= -1,
497 		.name	= "sth",
498 		.type	= INTEL_TH_SOURCE,
499 	},
500 	{
501 		.nres	= 1,
502 		.res	= {
503 			{
504 				.start	= REG_PTI_OFFSET,
505 				.end	= REG_PTI_OFFSET + REG_PTI_LENGTH - 1,
506 				.flags	= IORESOURCE_MEM,
507 			},
508 		},
509 		.id	= -1,
510 		.name	= "pti",
511 		.type	= INTEL_TH_OUTPUT,
512 		.otype	= GTH_PTI,
513 		.scrpd	= SCRPD_PTI_IS_PRIM_DEST,
514 	},
515 	{
516 		.nres	= 1,
517 		.res	= {
518 			{
519 				.start	= REG_PTI_OFFSET,
520 				.end	= REG_PTI_OFFSET + REG_PTI_LENGTH - 1,
521 				.flags	= IORESOURCE_MEM,
522 			},
523 		},
524 		.id	= -1,
525 		.name	= "lpp",
526 		.type	= INTEL_TH_OUTPUT,
527 		.otype	= GTH_LPP,
528 		.scrpd	= SCRPD_PTI_IS_PRIM_DEST,
529 	},
530 	{
531 		.nres	= 1,
532 		.res	= {
533 			{
534 				.start	= REG_DCIH_OFFSET,
535 				.end	= REG_DCIH_OFFSET + REG_DCIH_LENGTH - 1,
536 				.flags	= IORESOURCE_MEM,
537 			},
538 		},
539 		.id	= -1,
540 		.name	= "dcih",
541 		.type	= INTEL_TH_OUTPUT,
542 	},
543 };
544 
545 #ifdef CONFIG_MODULES
546 static void __intel_th_request_hub_module(struct work_struct *work)
547 {
548 	struct intel_th *th = container_of(work, struct intel_th,
549 					   request_module_work);
550 
551 	request_module("intel_th_%s", th->hub->name);
552 }
553 
554 static int intel_th_request_hub_module(struct intel_th *th)
555 {
556 	INIT_WORK(&th->request_module_work, __intel_th_request_hub_module);
557 	schedule_work(&th->request_module_work);
558 
559 	return 0;
560 }
561 
562 static void intel_th_request_hub_module_flush(struct intel_th *th)
563 {
564 	flush_work(&th->request_module_work);
565 }
566 #else
567 static inline int intel_th_request_hub_module(struct intel_th *th)
568 {
569 	return -EINVAL;
570 }
571 
572 static inline void intel_th_request_hub_module_flush(struct intel_th *th)
573 {
574 }
575 #endif /* CONFIG_MODULES */
576 
577 static struct intel_th_device *
578 intel_th_subdevice_alloc(struct intel_th *th,
579 			 const struct intel_th_subdevice *subdev)
580 {
581 	struct intel_th_device *thdev;
582 	struct resource res[3];
583 	unsigned int req = 0;
584 	bool is64bit = false;
585 	int r, err;
586 
587 	thdev = intel_th_device_alloc(th, subdev->type, subdev->name,
588 				      subdev->id);
589 	if (!thdev)
590 		return ERR_PTR(-ENOMEM);
591 
592 	thdev->drvdata = th->drvdata;
593 
594 	for (r = 0; r < th->num_resources; r++)
595 		if (th->resource[r].flags & IORESOURCE_MEM_64) {
596 			is64bit = true;
597 			break;
598 		}
599 
600 	memcpy(res, subdev->res,
601 	       sizeof(struct resource) * subdev->nres);
602 
603 	for (r = 0; r < subdev->nres; r++) {
604 		struct resource *devres = th->resource;
605 		int bar = 0; /* cut subdevices' MMIO from resource[0] */
606 
607 		/*
608 		 * Take .end == 0 to mean 'take the whole bar',
609 		 * .start then tells us which bar it is. Default to
610 		 * TH_MMIO_CONFIG.
611 		 */
612 		if (!res[r].end && res[r].flags == IORESOURCE_MEM) {
613 			bar = res[r].start;
614 			if (is64bit)
615 				bar *= 2;
616 			res[r].start = 0;
617 			res[r].end = resource_size(&devres[bar]) - 1;
618 		}
619 
620 		if (res[r].flags & IORESOURCE_MEM) {
621 			res[r].start	+= devres[bar].start;
622 			res[r].end	+= devres[bar].start;
623 
624 			dev_dbg(th->dev, "%s:%d @ %pR\n",
625 				subdev->name, r, &res[r]);
626 		} else if (res[r].flags & IORESOURCE_IRQ) {
627 			res[r].start	= th->irq;
628 		}
629 	}
630 
631 	err = intel_th_device_add_resources(thdev, res, subdev->nres);
632 	if (err) {
633 		put_device(&thdev->dev);
634 		goto fail_put_device;
635 	}
636 
637 	if (subdev->type == INTEL_TH_OUTPUT) {
638 		thdev->dev.devt = MKDEV(th->major, th->num_thdevs);
639 		thdev->output.type = subdev->otype;
640 		thdev->output.port = -1;
641 		thdev->output.scratchpad = subdev->scrpd;
642 	} else if (subdev->type == INTEL_TH_SWITCH) {
643 		thdev->host_mode =
644 			INTEL_TH_CAP(th, host_mode_only) ? true : host_mode;
645 		th->hub = thdev;
646 	}
647 
648 	err = device_add(&thdev->dev);
649 	if (err) {
650 		put_device(&thdev->dev);
651 		goto fail_free_res;
652 	}
653 
654 	/* need switch driver to be loaded to enumerate the rest */
655 	if (subdev->type == INTEL_TH_SWITCH && !req) {
656 		err = intel_th_request_hub_module(th);
657 		if (!err)
658 			req++;
659 	}
660 
661 	return thdev;
662 
663 fail_free_res:
664 	kfree(thdev->resource);
665 
666 fail_put_device:
667 	put_device(&thdev->dev);
668 
669 	return ERR_PTR(err);
670 }
671 
672 /**
673  * intel_th_output_enable() - find and enable a device for a given output type
674  * @th:		Intel TH instance
675  * @otype:	output type
676  *
677  * Go through the unallocated output devices, find the first one whos type
678  * matches @otype and instantiate it. These devices are removed when the hub
679  * device is removed, see intel_th_remove().
680  */
681 int intel_th_output_enable(struct intel_th *th, unsigned int otype)
682 {
683 	struct intel_th_device *thdev;
684 	int src = 0, dst = 0;
685 
686 	for (src = 0, dst = 0; dst <= th->num_thdevs; src++, dst++) {
687 		for (; src < ARRAY_SIZE(intel_th_subdevices); src++) {
688 			if (intel_th_subdevices[src].type != INTEL_TH_OUTPUT)
689 				continue;
690 
691 			if (intel_th_subdevices[src].otype != otype)
692 				continue;
693 
694 			break;
695 		}
696 
697 		/* no unallocated matching subdevices */
698 		if (src == ARRAY_SIZE(intel_th_subdevices))
699 			return -ENODEV;
700 
701 		for (; dst < th->num_thdevs; dst++) {
702 			if (th->thdev[dst]->type != INTEL_TH_OUTPUT)
703 				continue;
704 
705 			if (th->thdev[dst]->output.type != otype)
706 				continue;
707 
708 			break;
709 		}
710 
711 		/*
712 		 * intel_th_subdevices[src] matches our requirements and is
713 		 * not matched in th::thdev[]
714 		 */
715 		if (dst == th->num_thdevs)
716 			goto found;
717 	}
718 
719 	return -ENODEV;
720 
721 found:
722 	thdev = intel_th_subdevice_alloc(th, &intel_th_subdevices[src]);
723 	if (IS_ERR(thdev))
724 		return PTR_ERR(thdev);
725 
726 	th->thdev[th->num_thdevs++] = thdev;
727 
728 	return 0;
729 }
730 EXPORT_SYMBOL_GPL(intel_th_output_enable);
731 
732 static int intel_th_populate(struct intel_th *th)
733 {
734 	int src;
735 
736 	/* create devices for each intel_th_subdevice */
737 	for (src = 0; src < ARRAY_SIZE(intel_th_subdevices); src++) {
738 		const struct intel_th_subdevice *subdev =
739 			&intel_th_subdevices[src];
740 		struct intel_th_device *thdev;
741 
742 		/* only allow SOURCE and SWITCH devices in host mode */
743 		if ((INTEL_TH_CAP(th, host_mode_only) || host_mode) &&
744 		    subdev->type == INTEL_TH_OUTPUT)
745 			continue;
746 
747 		/*
748 		 * don't enable port OUTPUTs in this path; SWITCH enables them
749 		 * via intel_th_output_enable()
750 		 */
751 		if (subdev->type == INTEL_TH_OUTPUT &&
752 		    subdev->otype != GTH_NONE)
753 			continue;
754 
755 		thdev = intel_th_subdevice_alloc(th, subdev);
756 		/* note: caller should free subdevices from th::thdev[] */
757 		if (IS_ERR(thdev))
758 			return PTR_ERR(thdev);
759 
760 		th->thdev[th->num_thdevs++] = thdev;
761 	}
762 
763 	return 0;
764 }
765 
766 static int match_devt(struct device *dev, void *data)
767 {
768 	dev_t devt = (dev_t)(unsigned long)data;
769 
770 	return dev->devt == devt;
771 }
772 
773 static int intel_th_output_open(struct inode *inode, struct file *file)
774 {
775 	const struct file_operations *fops;
776 	struct intel_th_driver *thdrv;
777 	struct device *dev;
778 	int err;
779 
780 	dev = bus_find_device(&intel_th_bus, NULL,
781 			      (void *)(unsigned long)inode->i_rdev,
782 			      match_devt);
783 	if (!dev || !dev->driver)
784 		return -ENODEV;
785 
786 	thdrv = to_intel_th_driver(dev->driver);
787 	fops = fops_get(thdrv->fops);
788 	if (!fops)
789 		return -ENODEV;
790 
791 	replace_fops(file, fops);
792 
793 	file->private_data = to_intel_th_device(dev);
794 
795 	if (file->f_op->open) {
796 		err = file->f_op->open(inode, file);
797 		return err;
798 	}
799 
800 	return 0;
801 }
802 
803 static const struct file_operations intel_th_output_fops = {
804 	.open	= intel_th_output_open,
805 	.llseek	= noop_llseek,
806 };
807 
808 /**
809  * intel_th_alloc() - allocate a new Intel TH device and its subdevices
810  * @dev:	parent device
811  * @devres:	parent's resources
812  * @ndevres:	number of resources
813  * @irq:	irq number
814  */
815 struct intel_th *
816 intel_th_alloc(struct device *dev, struct intel_th_drvdata *drvdata,
817 	       struct resource *devres, unsigned int ndevres, int irq)
818 {
819 	struct intel_th *th;
820 	int err, r;
821 
822 	if (irq == -1)
823 		for (r = 0; r < ndevres; r++)
824 			if (devres[r].flags & IORESOURCE_IRQ) {
825 				irq = devres[r].start;
826 				break;
827 			}
828 
829 	th = kzalloc(sizeof(*th), GFP_KERNEL);
830 	if (!th)
831 		return ERR_PTR(-ENOMEM);
832 
833 	th->id = ida_simple_get(&intel_th_ida, 0, 0, GFP_KERNEL);
834 	if (th->id < 0) {
835 		err = th->id;
836 		goto err_alloc;
837 	}
838 
839 	th->major = __register_chrdev(0, 0, TH_POSSIBLE_OUTPUTS,
840 				      "intel_th/output", &intel_th_output_fops);
841 	if (th->major < 0) {
842 		err = th->major;
843 		goto err_ida;
844 	}
845 	th->dev = dev;
846 	th->drvdata = drvdata;
847 
848 	th->resource = devres;
849 	th->num_resources = ndevres;
850 	th->irq = irq;
851 
852 	dev_set_drvdata(dev, th);
853 
854 	pm_runtime_no_callbacks(dev);
855 	pm_runtime_put(dev);
856 	pm_runtime_allow(dev);
857 
858 	err = intel_th_populate(th);
859 	if (err) {
860 		/* free the subdevices and undo everything */
861 		intel_th_free(th);
862 		return ERR_PTR(err);
863 	}
864 
865 	return th;
866 
867 err_ida:
868 	ida_simple_remove(&intel_th_ida, th->id);
869 
870 err_alloc:
871 	kfree(th);
872 
873 	return ERR_PTR(err);
874 }
875 EXPORT_SYMBOL_GPL(intel_th_alloc);
876 
877 void intel_th_free(struct intel_th *th)
878 {
879 	int i;
880 
881 	intel_th_request_hub_module_flush(th);
882 
883 	intel_th_device_remove(th->hub);
884 	for (i = 0; i < th->num_thdevs; i++) {
885 		if (th->thdev[i] != th->hub)
886 			intel_th_device_remove(th->thdev[i]);
887 		th->thdev[i] = NULL;
888 	}
889 
890 	th->num_thdevs = 0;
891 
892 	pm_runtime_get_sync(th->dev);
893 	pm_runtime_forbid(th->dev);
894 
895 	__unregister_chrdev(th->major, 0, TH_POSSIBLE_OUTPUTS,
896 			    "intel_th/output");
897 
898 	ida_simple_remove(&intel_th_ida, th->id);
899 
900 	kfree(th);
901 }
902 EXPORT_SYMBOL_GPL(intel_th_free);
903 
904 /**
905  * intel_th_trace_enable() - enable tracing for an output device
906  * @thdev:	output device that requests tracing be enabled
907  */
908 int intel_th_trace_enable(struct intel_th_device *thdev)
909 {
910 	struct intel_th_device *hub = to_intel_th_device(thdev->dev.parent);
911 	struct intel_th_driver *hubdrv = to_intel_th_driver(hub->dev.driver);
912 
913 	if (WARN_ON_ONCE(hub->type != INTEL_TH_SWITCH))
914 		return -EINVAL;
915 
916 	if (WARN_ON_ONCE(thdev->type != INTEL_TH_OUTPUT))
917 		return -EINVAL;
918 
919 	pm_runtime_get_sync(&thdev->dev);
920 	hubdrv->enable(hub, &thdev->output);
921 
922 	return 0;
923 }
924 EXPORT_SYMBOL_GPL(intel_th_trace_enable);
925 
926 /**
927  * intel_th_trace_disable() - disable tracing for an output device
928  * @thdev:	output device that requests tracing be disabled
929  */
930 int intel_th_trace_disable(struct intel_th_device *thdev)
931 {
932 	struct intel_th_device *hub = to_intel_th_device(thdev->dev.parent);
933 	struct intel_th_driver *hubdrv = to_intel_th_driver(hub->dev.driver);
934 
935 	WARN_ON_ONCE(hub->type != INTEL_TH_SWITCH);
936 	if (WARN_ON_ONCE(thdev->type != INTEL_TH_OUTPUT))
937 		return -EINVAL;
938 
939 	hubdrv->disable(hub, &thdev->output);
940 	pm_runtime_put(&thdev->dev);
941 
942 	return 0;
943 }
944 EXPORT_SYMBOL_GPL(intel_th_trace_disable);
945 
946 int intel_th_set_output(struct intel_th_device *thdev,
947 			unsigned int master)
948 {
949 	struct intel_th_device *hub = to_intel_th_hub(thdev);
950 	struct intel_th_driver *hubdrv = to_intel_th_driver(hub->dev.driver);
951 
952 	/* In host mode, this is up to the external debugger, do nothing. */
953 	if (hub->host_mode)
954 		return 0;
955 
956 	if (!hubdrv->set_output)
957 		return -ENOTSUPP;
958 
959 	return hubdrv->set_output(hub, master);
960 }
961 EXPORT_SYMBOL_GPL(intel_th_set_output);
962 
963 static int __init intel_th_init(void)
964 {
965 	intel_th_debug_init();
966 
967 	return bus_register(&intel_th_bus);
968 }
969 subsys_initcall(intel_th_init);
970 
971 static void __exit intel_th_exit(void)
972 {
973 	intel_th_debug_done();
974 
975 	bus_unregister(&intel_th_bus);
976 }
977 module_exit(intel_th_exit);
978 
979 MODULE_LICENSE("GPL v2");
980 MODULE_DESCRIPTION("Intel(R) Trace Hub controller driver");
981 MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");
982