Linux preempt-rt

Check our new training course

Real-Time Linux with PREEMPT_RT

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

Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
/*
 * Generic OPP OF helpers
 *
 * Copyright (C) 2009-2010 Texas Instruments Incorporated.
 *	Nishanth Menon
 *	Romit Dasgupta
 *	Kevin Hilman
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/cpu.h>
#include <linux/errno.h>
#include <linux/device.h>
#include <linux/of_device.h>
#include <linux/slab.h>
#include <linux/export.h>

#include "opp.h"

static struct opp_table *_managed_opp(const struct device_node *np)
{
	struct opp_table *opp_table, *managed_table = NULL;

	mutex_lock(&opp_table_lock);

	list_for_each_entry(opp_table, &opp_tables, node) {
		if (opp_table->np == np) {
			/*
			 * Multiple devices can point to the same OPP table and
			 * so will have same node-pointer, np.
			 *
			 * But the OPPs will be considered as shared only if the
			 * OPP table contains a "opp-shared" property.
			 */
			if (opp_table->shared_opp == OPP_TABLE_ACCESS_SHARED) {
				_get_opp_table_kref(opp_table);
				managed_table = opp_table;
			}

			break;
		}
	}

	mutex_unlock(&opp_table_lock);

	return managed_table;
}

void _of_init_opp_table(struct opp_table *opp_table, struct device *dev)
{
	struct device_node *np;

	/*
	 * Only required for backward compatibility with v1 bindings, but isn't
	 * harmful for other cases. And so we do it unconditionally.
	 */
	np = of_node_get(dev->of_node);
	if (np) {
		u32 val;

		if (!of_property_read_u32(np, "clock-latency", &val))
			opp_table->clock_latency_ns_max = val;
		of_property_read_u32(np, "voltage-tolerance",
				     &opp_table->voltage_tolerance_v1);
		of_node_put(np);
	}
}

static bool _opp_is_supported(struct device *dev, struct opp_table *opp_table,
			      struct device_node *np)
{
	unsigned int count = opp_table->supported_hw_count;
	u32 version;
	int ret;

	if (!opp_table->supported_hw) {
		/*
		 * In the case that no supported_hw has been set by the
		 * platform but there is an opp-supported-hw value set for
		 * an OPP then the OPP should not be enabled as there is
		 * no way to see if the hardware supports it.
		 */
		if (of_find_property(np, "opp-supported-hw", NULL))
			return false;
		else
			return true;
	}

	while (count--) {
		ret = of_property_read_u32_index(np, "opp-supported-hw", count,
						 &version);
		if (ret) {
			dev_warn(dev, "%s: failed to read opp-supported-hw property at index %d: %d\n",
				 __func__, count, ret);
			return false;
		}

		/* Both of these are bitwise masks of the versions */
		if (!(version & opp_table->supported_hw[count]))
			return false;
	}

	return true;
}

static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
			      struct opp_table *opp_table)
{
	u32 *microvolt, *microamp = NULL;
	int supplies, vcount, icount, ret, i, j;
	struct property *prop = NULL;
	char name[NAME_MAX];

	supplies = opp_table->regulator_count ? opp_table->regulator_count : 1;

	/* Search for "opp-microvolt-<name>" */
	if (opp_table->prop_name) {
		snprintf(name, sizeof(name), "opp-microvolt-%s",
			 opp_table->prop_name);
		prop = of_find_property(opp->np, name, NULL);
	}

	if (!prop) {
		/* Search for "opp-microvolt" */
		sprintf(name, "opp-microvolt");
		prop = of_find_property(opp->np, name, NULL);

		/* Missing property isn't a problem, but an invalid entry is */
		if (!prop) {
			if (!opp_table->regulator_count)
				return 0;

			dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
				__func__);
			return -EINVAL;
		}
	}

	vcount = of_property_count_u32_elems(opp->np, name);
	if (vcount < 0) {
		dev_err(dev, "%s: Invalid %s property (%d)\n",
			__func__, name, vcount);
		return vcount;
	}

	/* There can be one or three elements per supply */
	if (vcount != supplies && vcount != supplies * 3) {
		dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
			__func__, name, vcount, supplies);
		return -EINVAL;
	}

	microvolt = kmalloc_array(vcount, sizeof(*microvolt), GFP_KERNEL);
	if (!microvolt)
		return -ENOMEM;

	ret = of_property_read_u32_array(opp->np, name, microvolt, vcount);
	if (ret) {
		dev_err(dev, "%s: error parsing %s: %d\n", __func__, name, ret);
		ret = -EINVAL;
		goto free_microvolt;
	}

	/* Search for "opp-microamp-<name>" */
	prop = NULL;
	if (opp_table->prop_name) {
		snprintf(name, sizeof(name), "opp-microamp-%s",
			 opp_table->prop_name);
		prop = of_find_property(opp->np, name, NULL);
	}

	if (!prop) {
		/* Search for "opp-microamp" */
		sprintf(name, "opp-microamp");
		prop = of_find_property(opp->np, name, NULL);
	}

	if (prop) {
		icount = of_property_count_u32_elems(opp->np, name);
		if (icount < 0) {
			dev_err(dev, "%s: Invalid %s property (%d)\n", __func__,
				name, icount);
			ret = icount;
			goto free_microvolt;
		}

		if (icount != supplies) {
			dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
				__func__, name, icount, supplies);
			ret = -EINVAL;
			goto free_microvolt;
		}

		microamp = kmalloc_array(icount, sizeof(*microamp), GFP_KERNEL);
		if (!microamp) {
			ret = -EINVAL;
			goto free_microvolt;
		}

		ret = of_property_read_u32_array(opp->np, name, microamp,
						 icount);
		if (ret) {
			dev_err(dev, "%s: error parsing %s: %d\n", __func__,
				name, ret);
			ret = -EINVAL;
			goto free_microamp;
		}
	}

	for (i = 0, j = 0; i < supplies; i++) {
		opp->supplies[i].u_volt = microvolt[j++];

		if (vcount == supplies) {
			opp->supplies[i].u_volt_min = opp->supplies[i].u_volt;
			opp->supplies[i].u_volt_max = opp->supplies[i].u_volt;
		} else {
			opp->supplies[i].u_volt_min = microvolt[j++];
			opp->supplies[i].u_volt_max = microvolt[j++];
		}

		if (microamp)
			opp->supplies[i].u_amp = microamp[i];
	}

free_microamp:
	kfree(microamp);
free_microvolt:
	kfree(microvolt);

	return ret;
}

/**
 * dev_pm_opp_of_remove_table() - Free OPP table entries created from static DT
 *				  entries
 * @dev:	device pointer used to lookup OPP table.
 *
 * Free OPPs created using static entries present in DT.
 */
void dev_pm_opp_of_remove_table(struct device *dev)
{
	_dev_pm_opp_find_and_remove_table(dev, false);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);

/* Returns opp descriptor node for a device node, caller must
 * do of_node_put() */
static struct device_node *_opp_of_get_opp_desc_node(struct device_node *np)
{
	/*
	 * There should be only ONE phandle present in "operating-points-v2"
	 * property.
	 */

	return of_parse_phandle(np, "operating-points-v2", 0);
}

/* Returns opp descriptor node for a device, caller must do of_node_put() */
struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device *dev)
{
	return _opp_of_get_opp_desc_node(dev->of_node);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_opp_desc_node);

/**
 * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
 * @opp_table:	OPP table
 * @dev:	device for which we do this operation
 * @np:		device node
 *
 * This function adds an opp definition to the opp table and returns status. The
 * opp can be controlled using dev_pm_opp_enable/disable functions and may be
 * removed by dev_pm_opp_remove.
 *
 * Return:
 * 0		On success OR
 *		Duplicate OPPs (both freq and volt are same) and opp->available
 * -EEXIST	Freq are same and volt are different OR
 *		Duplicate OPPs (both freq and volt are same) and !opp->available
 * -ENOMEM	Memory allocation failure
 * -EINVAL	Failed parsing the OPP node
 */
static int _opp_add_static_v2(struct opp_table *opp_table, struct device *dev,
			      struct device_node *np)
{
	struct dev_pm_opp *new_opp;
	u64 rate;
	u32 val;
	int ret;

	new_opp = _opp_allocate(opp_table);
	if (!new_opp)
		return -ENOMEM;

	ret = of_property_read_u64(np, "opp-hz", &rate);
	if (ret < 0) {
		dev_err(dev, "%s: opp-hz not found\n", __func__);
		goto free_opp;
	}

	/* Check if the OPP supports hardware's hierarchy of versions or not */
	if (!_opp_is_supported(dev, opp_table, np)) {
		dev_dbg(dev, "OPP not supported by hardware: %llu\n", rate);
		goto free_opp;
	}

	/*
	 * Rate is defined as an unsigned long in clk API, and so casting
	 * explicitly to its type. Must be fixed once rate is 64 bit
	 * guaranteed in clk API.
	 */
	new_opp->rate = (unsigned long)rate;
	new_opp->turbo = of_property_read_bool(np, "turbo-mode");

	new_opp->np = np;
	new_opp->dynamic = false;
	new_opp->available = true;

	if (!of_property_read_u32(np, "clock-latency-ns", &val))
		new_opp->clock_latency_ns = val;

	ret = opp_parse_supplies(new_opp, dev, opp_table);
	if (ret)
		goto free_opp;

	ret = _opp_add(dev, new_opp, opp_table);
	if (ret) {
		/* Don't return error for duplicate OPPs */
		if (ret == -EBUSY)
			ret = 0;
		goto free_opp;
	}

	/* OPP to select on device suspend */
	if (of_property_read_bool(np, "opp-suspend")) {
		if (opp_table->suspend_opp) {
			dev_warn(dev, "%s: Multiple suspend OPPs found (%lu %lu)\n",
				 __func__, opp_table->suspend_opp->rate,
				 new_opp->rate);
		} else {
			new_opp->suspend = true;
			opp_table->suspend_opp = new_opp;
		}
	}

	if (new_opp->clock_latency_ns > opp_table->clock_latency_ns_max)
		opp_table->clock_latency_ns_max = new_opp->clock_latency_ns;

	pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu latency:%lu\n",
		 __func__, new_opp->turbo, new_opp->rate,
		 new_opp->supplies[0].u_volt, new_opp->supplies[0].u_volt_min,
		 new_opp->supplies[0].u_volt_max, new_opp->clock_latency_ns);

	/*
	 * Notify the changes in the availability of the operable
	 * frequency/voltage list.
	 */
	blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADD, new_opp);
	return 0;

free_opp:
	_opp_free(new_opp);

	return ret;
}

/* Initializes OPP tables based on new bindings */
static int _of_add_opp_table_v2(struct device *dev, struct device_node *opp_np)
{
	struct device_node *np;
	struct opp_table *opp_table;
	int ret = 0, count = 0;

	opp_table = _managed_opp(opp_np);
	if (opp_table) {
		/* OPPs are already managed */
		if (!_add_opp_dev(dev, opp_table))
			ret = -ENOMEM;
		goto put_opp_table;
	}

	opp_table = dev_pm_opp_get_opp_table(dev);
	if (!opp_table)
		return -ENOMEM;

	/* We have opp-table node now, iterate over it and add OPPs */
	for_each_available_child_of_node(opp_np, np) {
		count++;

		ret = _opp_add_static_v2(opp_table, dev, np);
		if (ret) {
			dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
				ret);
			_dev_pm_opp_remove_table(opp_table, dev, false);
			of_node_put(np);
			goto put_opp_table;
		}
	}

	/* There should be one of more OPP defined */
	if (WARN_ON(!count)) {
		ret = -ENOENT;
		goto put_opp_table;
	}

	opp_table->np = opp_np;
	if (of_property_read_bool(opp_np, "opp-shared"))
		opp_table->shared_opp = OPP_TABLE_ACCESS_SHARED;
	else
		opp_table->shared_opp = OPP_TABLE_ACCESS_EXCLUSIVE;

put_opp_table:
	dev_pm_opp_put_opp_table(opp_table);

	return ret;
}

/* Initializes OPP tables based on old-deprecated bindings */
static int _of_add_opp_table_v1(struct device *dev)
{
	struct opp_table *opp_table;
	const struct property *prop;
	const __be32 *val;
	int nr, ret = 0;

	prop = of_find_property(dev->of_node, "operating-points", NULL);
	if (!prop)
		return -ENODEV;
	if (!prop->value)
		return -ENODATA;

	/*
	 * Each OPP is a set of tuples consisting of frequency and
	 * voltage like <freq-kHz vol-uV>.
	 */
	nr = prop->length / sizeof(u32);
	if (nr % 2) {
		dev_err(dev, "%s: Invalid OPP table\n", __func__);
		return -EINVAL;
	}

	opp_table = dev_pm_opp_get_opp_table(dev);
	if (!opp_table)
		return -ENOMEM;

	val = prop->value;
	while (nr) {
		unsigned long freq = be32_to_cpup(val++) * 1000;
		unsigned long volt = be32_to_cpup(val++);

		ret = _opp_add_v1(opp_table, dev, freq, volt, false);
		if (ret) {
			dev_err(dev, "%s: Failed to add OPP %ld (%d)\n",
				__func__, freq, ret);
			_dev_pm_opp_remove_table(opp_table, dev, false);
			break;
		}
		nr -= 2;
	}

	dev_pm_opp_put_opp_table(opp_table);
	return ret;
}

/**
 * dev_pm_opp_of_add_table() - Initialize opp table from device tree
 * @dev:	device pointer used to lookup OPP table.
 *
 * Register the initial OPP table with the OPP library for given device.
 *
 * Return:
 * 0		On success OR
 *		Duplicate OPPs (both freq and volt are same) and opp->available
 * -EEXIST	Freq are same and volt are different OR
 *		Duplicate OPPs (both freq and volt are same) and !opp->available
 * -ENOMEM	Memory allocation failure
 * -ENODEV	when 'operating-points' property is not found or is invalid data
 *		in device node.
 * -ENODATA	when empty 'operating-points' property is found
 * -EINVAL	when invalid entries are found in opp-v2 table
 */
int dev_pm_opp_of_add_table(struct device *dev)
{
	struct device_node *opp_np;
	int ret;

	/*
	 * OPPs have two version of bindings now. The older one is deprecated,
	 * try for the new binding first.
	 */
	opp_np = dev_pm_opp_of_get_opp_desc_node(dev);
	if (!opp_np) {
		/*
		 * Try old-deprecated bindings for backward compatibility with
		 * older dtbs.
		 */
		return _of_add_opp_table_v1(dev);
	}

	ret = _of_add_opp_table_v2(dev, opp_np);
	of_node_put(opp_np);

	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table);

/* CPU device specific helpers */

/**
 * dev_pm_opp_of_cpumask_remove_table() - Removes OPP table for @cpumask
 * @cpumask:	cpumask for which OPP table needs to be removed
 *
 * This removes the OPP tables for CPUs present in the @cpumask.
 * This should be used only to remove static entries created from DT.
 */
void dev_pm_opp_of_cpumask_remove_table(const struct cpumask *cpumask)
{
	_dev_pm_opp_cpumask_remove_table(cpumask, true);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_remove_table);

/**
 * dev_pm_opp_of_cpumask_add_table() - Adds OPP table for @cpumask
 * @cpumask:	cpumask for which OPP table needs to be added.
 *
 * This adds the OPP tables for CPUs present in the @cpumask.
 */
int dev_pm_opp_of_cpumask_add_table(const struct cpumask *cpumask)
{
	struct device *cpu_dev;
	int cpu, ret = 0;

	WARN_ON(cpumask_empty(cpumask));

	for_each_cpu(cpu, cpumask) {
		cpu_dev = get_cpu_device(cpu);
		if (!cpu_dev) {
			pr_err("%s: failed to get cpu%d device\n", __func__,
			       cpu);
			continue;
		}

		ret = dev_pm_opp_of_add_table(cpu_dev);
		if (ret) {
			/*
			 * OPP may get registered dynamically, don't print error
			 * message here.
			 */
			pr_debug("%s: couldn't find opp table for cpu:%d, %d\n",
				 __func__, cpu, ret);

			/* Free all other OPPs */
			dev_pm_opp_of_cpumask_remove_table(cpumask);
			break;
		}
	}

	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_add_table);

/*
 * Works only for OPP v2 bindings.
 *
 * Returns -ENOENT if operating-points-v2 bindings aren't supported.
 */
/**
 * dev_pm_opp_of_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with
 *				      @cpu_dev using operating-points-v2
 *				      bindings.
 *
 * @cpu_dev:	CPU device for which we do this operation
 * @cpumask:	cpumask to update with information of sharing CPUs
 *
 * This updates the @cpumask with CPUs that are sharing OPPs with @cpu_dev.
 *
 * Returns -ENOENT if operating-points-v2 isn't present for @cpu_dev.
 */
int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev,
				   struct cpumask *cpumask)
{
	struct device_node *np, *tmp_np, *cpu_np;
	int cpu, ret = 0;

	/* Get OPP descriptor node */
	np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
	if (!np) {
		dev_dbg(cpu_dev, "%s: Couldn't find opp node.\n", __func__);
		return -ENOENT;
	}

	cpumask_set_cpu(cpu_dev->id, cpumask);

	/* OPPs are shared ? */
	if (!of_property_read_bool(np, "opp-shared"))
		goto put_cpu_node;

	for_each_possible_cpu(cpu) {
		if (cpu == cpu_dev->id)
			continue;

		cpu_np = of_cpu_device_node_get(cpu);
		if (!cpu_np) {
			dev_err(cpu_dev, "%s: failed to get cpu%d node\n",
				__func__, cpu);
			ret = -ENOENT;
			goto put_cpu_node;
		}

		/* Get OPP descriptor node */
		tmp_np = _opp_of_get_opp_desc_node(cpu_np);
		of_node_put(cpu_np);
		if (!tmp_np) {
			pr_err("%pOF: Couldn't find opp node\n", cpu_np);
			ret = -ENOENT;
			goto put_cpu_node;
		}

		/* CPUs are sharing opp node */
		if (np == tmp_np)
			cpumask_set_cpu(cpu, cpumask);

		of_node_put(tmp_np);
	}

put_cpu_node:
	of_node_put(np);
	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_sharing_cpus);