summaryrefslogtreecommitdiffstats
path: root/drivers/soc/qcom/smp2p.c
blob: c7300d54e444715dfc50b62eedfca0648b184e1a (plain)
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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2015, Sony Mobile Communications AB.
 * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
 */

#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/mailbox_client.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/soc/qcom/smem.h>
#include <linux/soc/qcom/smem_state.h>
#include <linux/spinlock.h>

/*
 * The Shared Memory Point to Point (SMP2P) protocol facilitates communication
 * of a single 32-bit value between two processors.  Each value has a single
 * writer (the local side) and a single reader (the remote side). Values are
 * uniquely identified in the system by the directed edge (local processor ID
 * to remote processor ID) and a string identifier.
 *
 * Each processor is responsible for creating the outgoing SMEM items and each
 * item is writable by the local processor and readable by the remote
 * processor.  By using two separate SMEM items that are single-reader and
 * single-writer, SMP2P does not require any remote locking mechanisms.
 *
 * The driver uses the Linux GPIO and interrupt framework to expose a virtual
 * GPIO for each outbound entry and a virtual interrupt controller for each
 * inbound entry.
 */

#define SMP2P_MAX_ENTRY 16
#define SMP2P_MAX_ENTRY_NAME 16

#define SMP2P_FEATURE_SSR_ACK 0x1

#define SMP2P_MAGIC 0x504d5324

/**
 * struct smp2p_smem_item - in memory communication structure
 * @magic:		magic number
 * @version:		version - must be 1
 * @features:		features flag - currently unused
 * @local_pid:		processor id of sending end
 * @remote_pid:		processor id of receiving end
 * @total_entries:	number of entries - always SMP2P_MAX_ENTRY
 * @valid_entries:	number of allocated entries
 * @flags:
 * @entries:		individual communication entries
 *     @name:		name of the entry
 *     @value:		content of the entry
 */
struct smp2p_smem_item {
	u32 magic;
	u8 version;
	unsigned features:24;
	u16 local_pid;
	u16 remote_pid;
	u16 total_entries;
	u16 valid_entries;
	u32 flags;

	struct {
		u8 name[SMP2P_MAX_ENTRY_NAME];
		u32 value;
	} entries[SMP2P_MAX_ENTRY];
} __packed;

/**
 * struct smp2p_entry - driver context matching one entry
 * @node:	list entry to keep track of allocated entries
 * @smp2p:	reference to the device driver context
 * @name:	name of the entry, to match against smp2p_smem_item
 * @value:	pointer to smp2p_smem_item entry value
 * @last_value:	last handled value
 * @domain:	irq_domain for inbound entries
 * @irq_enabled:bitmap to track enabled irq bits
 * @irq_rising:	bitmap to mark irq bits for rising detection
 * @irq_falling:bitmap to mark irq bits for falling detection
 * @state:	smem state handle
 * @lock:	spinlock to protect read-modify-write of the value
 */
struct smp2p_entry {
	struct list_head node;
	struct qcom_smp2p *smp2p;

	const char *name;
	u32 *value;
	u32 last_value;

	struct irq_domain *domain;
	DECLARE_BITMAP(irq_enabled, 32);
	DECLARE_BITMAP(irq_rising, 32);
	DECLARE_BITMAP(irq_falling, 32);

	struct qcom_smem_state *state;

	spinlock_t lock;
};

#define SMP2P_INBOUND	0
#define SMP2P_OUTBOUND	1

/**
 * struct qcom_smp2p - device driver context
 * @dev:	device driver handle
 * @in:		pointer to the inbound smem item
 * @smem_items:	ids of the two smem items
 * @valid_entries: already scanned inbound entries
 * @local_pid:	processor id of the inbound edge
 * @remote_pid:	processor id of the outbound edge
 * @ipc_regmap:	regmap for the outbound ipc
 * @ipc_offset:	offset within the regmap
 * @ipc_bit:	bit in regmap@offset to kick to signal remote processor
 * @mbox_client: mailbox client handle
 * @mbox_chan:	apcs ipc mailbox channel handle
 * @inbound:	list of inbound entries
 * @outbound:	list of outbound entries
 */
struct qcom_smp2p {
	struct device *dev;

	struct smp2p_smem_item *in;
	struct smp2p_smem_item *out;

	unsigned smem_items[SMP2P_OUTBOUND + 1];

	unsigned valid_entries;

	unsigned local_pid;
	unsigned remote_pid;

	struct regmap *ipc_regmap;
	int ipc_offset;
	int ipc_bit;

	struct mbox_client mbox_client;
	struct mbox_chan *mbox_chan;

	struct list_head inbound;
	struct list_head outbound;
};

static void qcom_smp2p_kick(struct qcom_smp2p *smp2p)
{
	/* Make sure any updated data is written before the kick */
	wmb();

	if (smp2p->mbox_chan) {
		mbox_send_message(smp2p->mbox_chan, NULL);
		mbox_client_txdone(smp2p->mbox_chan, 0);
	} else {
		regmap_write(smp2p->ipc_regmap, smp2p->ipc_offset, BIT(smp2p->ipc_bit));
	}
}

/**
 * qcom_smp2p_intr() - interrupt handler for incoming notifications
 * @irq:	unused
 * @data:	smp2p driver context
 *
 * Handle notifications from the remote side to handle newly allocated entries
 * or any changes to the state bits of existing entries.
 */
static irqreturn_t qcom_smp2p_intr(int irq, void *data)
{
	struct smp2p_smem_item *in;
	struct smp2p_entry *entry;
	struct qcom_smp2p *smp2p = data;
	unsigned smem_id = smp2p->smem_items[SMP2P_INBOUND];
	unsigned pid = smp2p->remote_pid;
	size_t size;
	int irq_pin;
	u32 status;
	char buf[SMP2P_MAX_ENTRY_NAME];
	u32 val;
	int i;

	in = smp2p->in;

	/* Acquire smem item, if not already found */
	if (!in) {
		in = qcom_smem_get(pid, smem_id, &size);
		if (IS_ERR(in)) {
			dev_err(smp2p->dev,
				"Unable to acquire remote smp2p item\n");
			return IRQ_HANDLED;
		}

		smp2p->in = in;
	}

	/* Match newly created entries */
	for (i = smp2p->valid_entries; i < in->valid_entries; i++) {
		list_for_each_entry(entry, &smp2p->inbound, node) {
			memcpy(buf, in->entries[i].name, sizeof(buf));
			if (!strcmp(buf, entry->name)) {
				entry->value = &in->entries[i].value;
				break;
			}
		}
	}
	smp2p->valid_entries = i;

	/* Fire interrupts based on any value changes */
	list_for_each_entry(entry, &smp2p->inbound, node) {
		/* Ignore entries not yet allocated by the remote side */
		if (!entry->value)
			continue;

		val = readl(entry->value);

		status = val ^ entry->last_value;
		entry->last_value = val;

		/* No changes of this entry? */
		if (!status)
			continue;

		for_each_set_bit(i, entry->irq_enabled, 32) {
			if (!(status & BIT(i)))
				continue;

			if ((val & BIT(i) && test_bit(i, entry->irq_rising)) ||
			    (!(val & BIT(i)) && test_bit(i, entry->irq_falling))) {
				irq_pin = irq_find_mapping(entry->domain, i);
				handle_nested_irq(irq_pin);
			}
		}
	}

	return IRQ_HANDLED;
}

static void smp2p_mask_irq(struct irq_data *irqd)
{
	struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
	irq_hw_number_t irq = irqd_to_hwirq(irqd);

	clear_bit(irq, entry->irq_enabled);
}

static void smp2p_unmask_irq(struct irq_data *irqd)
{
	struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
	irq_hw_number_t irq = irqd_to_hwirq(irqd);

	set_bit(irq, entry->irq_enabled);
}

static int smp2p_set_irq_type(struct irq_data *irqd, unsigned int type)
{
	struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
	irq_hw_number_t irq = irqd_to_hwirq(irqd);

	if (!(type & IRQ_TYPE_EDGE_BOTH))
		return -EINVAL;

	if (type & IRQ_TYPE_EDGE_RISING)
		set_bit(irq, entry->irq_rising);
	else
		clear_bit(irq, entry->irq_rising);

	if (type & IRQ_TYPE_EDGE_FALLING)
		set_bit(irq, entry->irq_falling);
	else
		clear_bit(irq, entry->irq_falling);

	return 0;
}

static struct irq_chip smp2p_irq_chip = {
	.name           = "smp2p",
	.irq_mask       = smp2p_mask_irq,
	.irq_unmask     = smp2p_unmask_irq,
	.irq_set_type	= smp2p_set_irq_type,
};

static int smp2p_irq_map(struct irq_domain *d,
			 unsigned int irq,
			 irq_hw_number_t hw)
{
	struct smp2p_entry *entry = d->host_data;

	irq_set_chip_and_handler(irq, &smp2p_irq_chip, handle_level_irq);
	irq_set_chip_data(irq, entry);
	irq_set_nested_thread(irq, 1);
	irq_set_noprobe(irq);

	return 0;
}

static const struct irq_domain_ops smp2p_irq_ops = {
	.map = smp2p_irq_map,
	.xlate = irq_domain_xlate_twocell,
};

static int qcom_smp2p_inbound_entry(struct qcom_smp2p *smp2p,
				    struct smp2p_entry *entry,
				    struct device_node *node)
{
	entry->domain = irq_domain_add_linear(node, 32, &smp2p_irq_ops, entry);
	if (!entry->domain) {
		dev_err(smp2p->dev, "failed to add irq_domain\n");
		return -ENOMEM;
	}

	return 0;
}

static int smp2p_update_bits(void *data, u32 mask, u32 value)
{
	struct smp2p_entry *entry = data;
	u32 orig;
	u32 val;

	spin_lock(&entry->lock);
	val = orig = readl(entry->value);
	val &= ~mask;
	val |= value;
	writel(val, entry->value);
	spin_unlock(&entry->lock);

	if (val != orig)
		qcom_smp2p_kick(entry->smp2p);

	return 0;
}

static const struct qcom_smem_state_ops smp2p_state_ops = {
	.update_bits = smp2p_update_bits,
};

static int qcom_smp2p_outbound_entry(struct qcom_smp2p *smp2p,
				     struct smp2p_entry *entry,
				     struct device_node *node)
{
	struct smp2p_smem_item *out = smp2p->out;
	char buf[SMP2P_MAX_ENTRY_NAME] = {};

	/* Allocate an entry from the smem item */
	strlcpy(buf, entry->name, SMP2P_MAX_ENTRY_NAME);
	memcpy(out->entries[out->valid_entries].name, buf, SMP2P_MAX_ENTRY_NAME);

	/* Make the logical entry reference the physical value */
	entry->value = &out->entries[out->valid_entries].value;

	out->valid_entries++;

	entry->state = qcom_smem_state_register(node, &smp2p_state_ops, entry);
	if (IS_ERR(entry->state)) {
		dev_err(smp2p->dev, "failed to register qcom_smem_state\n");
		return PTR_ERR(entry->state);
	}

	return 0;
}

static int qcom_smp2p_alloc_outbound_item(struct qcom_smp2p *smp2p)
{
	struct smp2p_smem_item *out;
	unsigned smem_id = smp2p->smem_items[SMP2P_OUTBOUND];
	unsigned pid = smp2p->remote_pid;
	int ret;

	ret = qcom_smem_alloc(pid, smem_id, sizeof(*out));
	if (ret < 0 && ret != -EEXIST) {
		if (ret != -EPROBE_DEFER)
			dev_err(smp2p->dev,
				"unable to allocate local smp2p item\n");
		return ret;
	}

	out = qcom_smem_get(pid, smem_id, NULL);
	if (IS_ERR(out)) {
		dev_err(smp2p->dev, "Unable to acquire local smp2p item\n");
		return PTR_ERR(out);
	}

	memset(out, 0, sizeof(*out));
	out->magic = SMP2P_MAGIC;
	out->local_pid = smp2p->local_pid;
	out->remote_pid = smp2p->remote_pid;
	out->total_entries = SMP2P_MAX_ENTRY;
	out->valid_entries = 0;

	/*
	 * Make sure the rest of the header is written before we validate the
	 * item by writing a valid version number.
	 */
	wmb();
	out->version = 1;

	qcom_smp2p_kick(smp2p);

	smp2p->out = out;

	return 0;
}

static int smp2p_parse_ipc(struct qcom_smp2p *smp2p)
{
	struct device_node *syscon;
	struct device *dev = smp2p->dev;
	const char *key;
	int ret;

	syscon = of_parse_phandle(dev->of_node, "qcom,ipc", 0);
	if (!syscon) {
		dev_err(dev, "no qcom,ipc node\n");
		return -ENODEV;
	}

	smp2p->ipc_regmap = syscon_node_to_regmap(syscon);
	if (IS_ERR(smp2p->ipc_regmap))
		return PTR_ERR(smp2p->ipc_regmap);

	key = "qcom,ipc";
	ret = of_property_read_u32_index(dev->of_node, key, 1, &smp2p->ipc_offset);
	if (ret < 0) {
		dev_err(dev, "no offset in %s\n", key);
		return -EINVAL;
	}

	ret = of_property_read_u32_index(dev->of_node, key, 2, &smp2p->ipc_bit);
	if (ret < 0) {
		dev_err(dev, "no bit in %s\n", key);
		return -EINVAL;
	}

	return 0;
}

static int qcom_smp2p_probe(struct platform_device *pdev)
{
	struct smp2p_entry *entry;
	struct device_node *node;
	struct qcom_smp2p *smp2p;
	const char *key;
	int irq;
	int ret;

	smp2p = devm_kzalloc(&pdev->dev, sizeof(*smp2p), GFP_KERNEL);
	if (!smp2p)
		return -ENOMEM;

	smp2p->dev = &pdev->dev;
	INIT_LIST_HEAD(&smp2p->inbound);
	INIT_LIST_HEAD(&smp2p->outbound);

	platform_set_drvdata(pdev, smp2p);

	key = "qcom,smem";
	ret = of_property_read_u32_array(pdev->dev.of_node, key,
					 smp2p->smem_items, 2);
	if (ret)
		return ret;

	key = "qcom,local-pid";
	ret = of_property_read_u32(pdev->dev.of_node, key, &smp2p->local_pid);
	if (ret)
		goto report_read_failure;

	key = "qcom,remote-pid";
	ret = of_property_read_u32(pdev->dev.of_node, key, &smp2p->remote_pid);
	if (ret)
		goto report_read_failure;

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		dev_err(&pdev->dev, "unable to acquire smp2p interrupt\n");
		return irq;
	}

	smp2p->mbox_client.dev = &pdev->dev;
	smp2p->mbox_client.knows_txdone = true;
	smp2p->mbox_chan = mbox_request_channel(&smp2p->mbox_client, 0);
	if (IS_ERR(smp2p->mbox_chan)) {
		if (PTR_ERR(smp2p->mbox_chan) != -ENODEV)
			return PTR_ERR(smp2p->mbox_chan);

		smp2p->mbox_chan = NULL;

		ret = smp2p_parse_ipc(smp2p);
		if (ret)
			return ret;
	}

	ret = qcom_smp2p_alloc_outbound_item(smp2p);
	if (ret < 0)
		goto release_mbox;

	for_each_available_child_of_node(pdev->dev.of_node, node) {
		entry = devm_kzalloc(&pdev->dev, sizeof(*entry), GFP_KERNEL);
		if (!entry) {
			ret = -ENOMEM;
			goto unwind_interfaces;
		}

		entry->smp2p = smp2p;
		spin_lock_init(&entry->lock);

		ret = of_property_read_string(node, "qcom,entry-name", &entry->name);
		if (ret < 0)
			goto unwind_interfaces;

		if (of_property_read_bool(node, "interrupt-controller")) {
			ret = qcom_smp2p_inbound_entry(smp2p, entry, node);
			if (ret < 0)
				goto unwind_interfaces;

			list_add(&entry->node, &smp2p->inbound);
		} else  {
			ret = qcom_smp2p_outbound_entry(smp2p, entry, node);
			if (ret < 0)
				goto unwind_interfaces;

			list_add(&entry->node, &smp2p->outbound);
		}
	}

	/* Kick the outgoing edge after allocating entries */
	qcom_smp2p_kick(smp2p);

	ret = devm_request_threaded_irq(&pdev->dev, irq,
					NULL, qcom_smp2p_intr,
					IRQF_ONESHOT,
					"smp2p", (void *)smp2p);
	if (ret) {
		dev_err(&pdev->dev, "failed to request interrupt\n");
		goto unwind_interfaces;
	}


	return 0;

unwind_interfaces:
	list_for_each_entry(entry, &smp2p->inbound, node)
		irq_domain_remove(entry->domain);

	list_for_each_entry(entry, &smp2p->outbound, node)
		qcom_smem_state_unregister(entry->state);

	smp2p->out->valid_entries = 0;

release_mbox:
	mbox_free_channel(smp2p->mbox_chan);

	return ret;

report_read_failure:
	dev_err(&pdev->dev, "failed to read %s\n", key);
	return -EINVAL;
}

static int qcom_smp2p_remove(struct platform_device *pdev)
{
	struct qcom_smp2p *smp2p = platform_get_drvdata(pdev);
	struct smp2p_entry *entry;

	list_for_each_entry(entry, &smp2p->inbound, node)
		irq_domain_remove(entry->domain);

	list_for_each_entry(entry, &smp2p->outbound, node)
		qcom_smem_state_unregister(entry->state);

	mbox_free_channel(smp2p->mbox_chan);

	smp2p->out->valid_entries = 0;

	return 0;
}

static const struct of_device_id qcom_smp2p_of_match[] = {
	{ .compatible = "qcom,smp2p" },
	{}
};
MODULE_DEVICE_TABLE(of, qcom_smp2p_of_match);

static struct platform_driver qcom_smp2p_driver = {
	.probe = qcom_smp2p_probe,
	.remove = qcom_smp2p_remove,
	.driver  = {
		.name  = "qcom_smp2p",
		.of_match_table = qcom_smp2p_of_match,
	},
};
module_platform_driver(qcom_smp2p_driver);

MODULE_DESCRIPTION("Qualcomm Shared Memory Point to Point driver");
MODULE_LICENSE("GPL v2");