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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2015, Sony Mobile Communications AB.
4 * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
5 */
6
7#include <linux/interrupt.h>
8#include <linux/list.h>
9#include <linux/io.h>
10#include <linux/of.h>
11#include <linux/irq.h>
12#include <linux/irqdomain.h>
13#include <linux/mailbox_client.h>
14#include <linux/mfd/syscon.h>
15#include <linux/module.h>
16#include <linux/platform_device.h>
17#include <linux/regmap.h>
18#include <linux/soc/qcom/smem.h>
19#include <linux/soc/qcom/smem_state.h>
20#include <linux/spinlock.h>
21
22/*
23 * The Shared Memory Point to Point (SMP2P) protocol facilitates communication
24 * of a single 32-bit value between two processors. Each value has a single
25 * writer (the local side) and a single reader (the remote side). Values are
26 * uniquely identified in the system by the directed edge (local processor ID
27 * to remote processor ID) and a string identifier.
28 *
29 * Each processor is responsible for creating the outgoing SMEM items and each
30 * item is writable by the local processor and readable by the remote
31 * processor. By using two separate SMEM items that are single-reader and
32 * single-writer, SMP2P does not require any remote locking mechanisms.
33 *
34 * The driver uses the Linux GPIO and interrupt framework to expose a virtual
35 * GPIO for each outbound entry and a virtual interrupt controller for each
36 * inbound entry.
37 */
38
39#define SMP2P_MAX_ENTRY 16
40#define SMP2P_MAX_ENTRY_NAME 16
41
42#define SMP2P_FEATURE_SSR_ACK 0x1
43
44#define SMP2P_MAGIC 0x504d5324
45
46/**
47 * struct smp2p_smem_item - in memory communication structure
48 * @magic: magic number
49 * @version: version - must be 1
50 * @features: features flag - currently unused
51 * @local_pid: processor id of sending end
52 * @remote_pid: processor id of receiving end
53 * @total_entries: number of entries - always SMP2P_MAX_ENTRY
54 * @valid_entries: number of allocated entries
55 * @flags:
56 * @entries: individual communication entries
57 * @name: name of the entry
58 * @value: content of the entry
59 */
60struct smp2p_smem_item {
61 u32 magic;
62 u8 version;
63 unsigned features:24;
64 u16 local_pid;
65 u16 remote_pid;
66 u16 total_entries;
67 u16 valid_entries;
68 u32 flags;
69
70 struct {
71 u8 name[SMP2P_MAX_ENTRY_NAME];
72 u32 value;
73 } entries[SMP2P_MAX_ENTRY];
74} __packed;
75
76/**
77 * struct smp2p_entry - driver context matching one entry
78 * @node: list entry to keep track of allocated entries
79 * @smp2p: reference to the device driver context
80 * @name: name of the entry, to match against smp2p_smem_item
81 * @value: pointer to smp2p_smem_item entry value
82 * @last_value: last handled value
83 * @domain: irq_domain for inbound entries
84 * @irq_enabled:bitmap to track enabled irq bits
85 * @irq_rising: bitmap to mark irq bits for rising detection
86 * @irq_falling:bitmap to mark irq bits for falling detection
87 * @state: smem state handle
88 * @lock: spinlock to protect read-modify-write of the value
89 */
90struct smp2p_entry {
91 struct list_head node;
92 struct qcom_smp2p *smp2p;
93
94 const char *name;
95 u32 *value;
96 u32 last_value;
97
98 struct irq_domain *domain;
99 DECLARE_BITMAP(irq_enabled, 32);
100 DECLARE_BITMAP(irq_rising, 32);
101 DECLARE_BITMAP(irq_falling, 32);
102
103 struct qcom_smem_state *state;
104
105 spinlock_t lock;
106};
107
108#define SMP2P_INBOUND 0
109#define SMP2P_OUTBOUND 1
110
111/**
112 * struct qcom_smp2p - device driver context
113 * @dev: device driver handle
114 * @in: pointer to the inbound smem item
115 * @smem_items: ids of the two smem items
116 * @valid_entries: already scanned inbound entries
117 * @local_pid: processor id of the inbound edge
118 * @remote_pid: processor id of the outbound edge
119 * @ipc_regmap: regmap for the outbound ipc
120 * @ipc_offset: offset within the regmap
121 * @ipc_bit: bit in regmap@offset to kick to signal remote processor
122 * @mbox_client: mailbox client handle
123 * @mbox_chan: apcs ipc mailbox channel handle
124 * @inbound: list of inbound entries
125 * @outbound: list of outbound entries
126 */
127struct qcom_smp2p {
128 struct device *dev;
129
130 struct smp2p_smem_item *in;
131 struct smp2p_smem_item *out;
132
133 unsigned smem_items[SMP2P_OUTBOUND + 1];
134
135 unsigned valid_entries;
136
137 unsigned local_pid;
138 unsigned remote_pid;
139
140 struct regmap *ipc_regmap;
141 int ipc_offset;
142 int ipc_bit;
143
144 struct mbox_client mbox_client;
145 struct mbox_chan *mbox_chan;
146
147 struct list_head inbound;
148 struct list_head outbound;
149};
150
151static void qcom_smp2p_kick(struct qcom_smp2p *smp2p)
152{
153 /* Make sure any updated data is written before the kick */
154 wmb();
155
156 if (smp2p->mbox_chan) {
157 mbox_send_message(smp2p->mbox_chan, NULL);
158 mbox_client_txdone(smp2p->mbox_chan, 0);
159 } else {
160 regmap_write(smp2p->ipc_regmap, smp2p->ipc_offset, BIT(smp2p->ipc_bit));
161 }
162}
163
164/**
165 * qcom_smp2p_intr() - interrupt handler for incoming notifications
166 * @irq: unused
167 * @data: smp2p driver context
168 *
169 * Handle notifications from the remote side to handle newly allocated entries
170 * or any changes to the state bits of existing entries.
171 */
172static irqreturn_t qcom_smp2p_intr(int irq, void *data)
173{
174 struct smp2p_smem_item *in;
175 struct smp2p_entry *entry;
176 struct qcom_smp2p *smp2p = data;
177 unsigned smem_id = smp2p->smem_items[SMP2P_INBOUND];
178 unsigned pid = smp2p->remote_pid;
179 size_t size;
180 int irq_pin;
181 u32 status;
182 char buf[SMP2P_MAX_ENTRY_NAME];
183 u32 val;
184 int i;
185
186 in = smp2p->in;
187
188 /* Acquire smem item, if not already found */
189 if (!in) {
190 in = qcom_smem_get(pid, smem_id, &size);
191 if (IS_ERR(in)) {
192 dev_err(smp2p->dev,
193 "Unable to acquire remote smp2p item\n");
194 return IRQ_HANDLED;
195 }
196
197 smp2p->in = in;
198 }
199
200 /* Match newly created entries */
201 for (i = smp2p->valid_entries; i < in->valid_entries; i++) {
202 list_for_each_entry(entry, &smp2p->inbound, node) {
203 memcpy(buf, in->entries[i].name, sizeof(buf));
204 if (!strcmp(buf, entry->name)) {
205 entry->value = &in->entries[i].value;
206 break;
207 }
208 }
209 }
210 smp2p->valid_entries = i;
211
212 /* Fire interrupts based on any value changes */
213 list_for_each_entry(entry, &smp2p->inbound, node) {
214 /* Ignore entries not yet allocated by the remote side */
215 if (!entry->value)
216 continue;
217
218 val = readl(entry->value);
219
220 status = val ^ entry->last_value;
221 entry->last_value = val;
222
223 /* No changes of this entry? */
224 if (!status)
225 continue;
226
227 for_each_set_bit(i, entry->irq_enabled, 32) {
228 if (!(status & BIT(i)))
229 continue;
230
231 if ((val & BIT(i) && test_bit(i, entry->irq_rising)) ||
232 (!(val & BIT(i)) && test_bit(i, entry->irq_falling))) {
233 irq_pin = irq_find_mapping(entry->domain, i);
234 handle_nested_irq(irq_pin);
235 }
236 }
237 }
238
239 return IRQ_HANDLED;
240}
241
242static void smp2p_mask_irq(struct irq_data *irqd)
243{
244 struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
245 irq_hw_number_t irq = irqd_to_hwirq(irqd);
246
247 clear_bit(irq, entry->irq_enabled);
248}
249
250static void smp2p_unmask_irq(struct irq_data *irqd)
251{
252 struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
253 irq_hw_number_t irq = irqd_to_hwirq(irqd);
254
255 set_bit(irq, entry->irq_enabled);
256}
257
258static int smp2p_set_irq_type(struct irq_data *irqd, unsigned int type)
259{
260 struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
261 irq_hw_number_t irq = irqd_to_hwirq(irqd);
262
263 if (!(type & IRQ_TYPE_EDGE_BOTH))
264 return -EINVAL;
265
266 if (type & IRQ_TYPE_EDGE_RISING)
267 set_bit(irq, entry->irq_rising);
268 else
269 clear_bit(irq, entry->irq_rising);
270
271 if (type & IRQ_TYPE_EDGE_FALLING)
272 set_bit(irq, entry->irq_falling);
273 else
274 clear_bit(irq, entry->irq_falling);
275
276 return 0;
277}
278
279static struct irq_chip smp2p_irq_chip = {
280 .name = "smp2p",
281 .irq_mask = smp2p_mask_irq,
282 .irq_unmask = smp2p_unmask_irq,
283 .irq_set_type = smp2p_set_irq_type,
284};
285
286static int smp2p_irq_map(struct irq_domain *d,
287 unsigned int irq,
288 irq_hw_number_t hw)
289{
290 struct smp2p_entry *entry = d->host_data;
291
292 irq_set_chip_and_handler(irq, &smp2p_irq_chip, handle_level_irq);
293 irq_set_chip_data(irq, entry);
294 irq_set_nested_thread(irq, 1);
295 irq_set_noprobe(irq);
296
297 return 0;
298}
299
300static const struct irq_domain_ops smp2p_irq_ops = {
301 .map = smp2p_irq_map,
302 .xlate = irq_domain_xlate_twocell,
303};
304
305static int qcom_smp2p_inbound_entry(struct qcom_smp2p *smp2p,
306 struct smp2p_entry *entry,
307 struct device_node *node)
308{
309 entry->domain = irq_domain_add_linear(node, 32, &smp2p_irq_ops, entry);
310 if (!entry->domain) {
311 dev_err(smp2p->dev, "failed to add irq_domain\n");
312 return -ENOMEM;
313 }
314
315 return 0;
316}
317
318static int smp2p_update_bits(void *data, u32 mask, u32 value)
319{
320 struct smp2p_entry *entry = data;
321 u32 orig;
322 u32 val;
323
324 spin_lock(&entry->lock);
325 val = orig = readl(entry->value);
326 val &= ~mask;
327 val |= value;
328 writel(val, entry->value);
329 spin_unlock(&entry->lock);
330
331 if (val != orig)
332 qcom_smp2p_kick(entry->smp2p);
333
334 return 0;
335}
336
337static const struct qcom_smem_state_ops smp2p_state_ops = {
338 .update_bits = smp2p_update_bits,
339};
340
341static int qcom_smp2p_outbound_entry(struct qcom_smp2p *smp2p,
342 struct smp2p_entry *entry,
343 struct device_node *node)
344{
345 struct smp2p_smem_item *out = smp2p->out;
346 char buf[SMP2P_MAX_ENTRY_NAME] = {};
347
348 /* Allocate an entry from the smem item */
349 strlcpy(buf, entry->name, SMP2P_MAX_ENTRY_NAME);
350 memcpy(out->entries[out->valid_entries].name, buf, SMP2P_MAX_ENTRY_NAME);
351
352 /* Make the logical entry reference the physical value */
353 entry->value = &out->entries[out->valid_entries].value;
354
355 out->valid_entries++;
356
357 entry->state = qcom_smem_state_register(node, &smp2p_state_ops, entry);
358 if (IS_ERR(entry->state)) {
359 dev_err(smp2p->dev, "failed to register qcom_smem_state\n");
360 return PTR_ERR(entry->state);
361 }
362
363 return 0;
364}
365
366static int qcom_smp2p_alloc_outbound_item(struct qcom_smp2p *smp2p)
367{
368 struct smp2p_smem_item *out;
369 unsigned smem_id = smp2p->smem_items[SMP2P_OUTBOUND];
370 unsigned pid = smp2p->remote_pid;
371 int ret;
372
373 ret = qcom_smem_alloc(pid, smem_id, sizeof(*out));
374 if (ret < 0 && ret != -EEXIST) {
375 if (ret != -EPROBE_DEFER)
376 dev_err(smp2p->dev,
377 "unable to allocate local smp2p item\n");
378 return ret;
379 }
380
381 out = qcom_smem_get(pid, smem_id, NULL);
382 if (IS_ERR(out)) {
383 dev_err(smp2p->dev, "Unable to acquire local smp2p item\n");
384 return PTR_ERR(out);
385 }
386
387 memset(out, 0, sizeof(*out));
388 out->magic = SMP2P_MAGIC;
389 out->local_pid = smp2p->local_pid;
390 out->remote_pid = smp2p->remote_pid;
391 out->total_entries = SMP2P_MAX_ENTRY;
392 out->valid_entries = 0;
393
394 /*
395 * Make sure the rest of the header is written before we validate the
396 * item by writing a valid version number.
397 */
398 wmb();
399 out->version = 1;
400
401 qcom_smp2p_kick(smp2p);
402
403 smp2p->out = out;
404
405 return 0;
406}
407
408static int smp2p_parse_ipc(struct qcom_smp2p *smp2p)
409{
410 struct device_node *syscon;
411 struct device *dev = smp2p->dev;
412 const char *key;
413 int ret;
414
415 syscon = of_parse_phandle(dev->of_node, "qcom,ipc", 0);
416 if (!syscon) {
417 dev_err(dev, "no qcom,ipc node\n");
418 return -ENODEV;
419 }
420
421 smp2p->ipc_regmap = syscon_node_to_regmap(syscon);
422 if (IS_ERR(smp2p->ipc_regmap))
423 return PTR_ERR(smp2p->ipc_regmap);
424
425 key = "qcom,ipc";
426 ret = of_property_read_u32_index(dev->of_node, key, 1, &smp2p->ipc_offset);
427 if (ret < 0) {
428 dev_err(dev, "no offset in %s\n", key);
429 return -EINVAL;
430 }
431
432 ret = of_property_read_u32_index(dev->of_node, key, 2, &smp2p->ipc_bit);
433 if (ret < 0) {
434 dev_err(dev, "no bit in %s\n", key);
435 return -EINVAL;
436 }
437
438 return 0;
439}
440
441static int qcom_smp2p_probe(struct platform_device *pdev)
442{
443 struct smp2p_entry *entry;
444 struct device_node *node;
445 struct qcom_smp2p *smp2p;
446 const char *key;
447 int irq;
448 int ret;
449
450 smp2p = devm_kzalloc(&pdev->dev, sizeof(*smp2p), GFP_KERNEL);
451 if (!smp2p)
452 return -ENOMEM;
453
454 smp2p->dev = &pdev->dev;
455 INIT_LIST_HEAD(&smp2p->inbound);
456 INIT_LIST_HEAD(&smp2p->outbound);
457
458 platform_set_drvdata(pdev, smp2p);
459
460 key = "qcom,smem";
461 ret = of_property_read_u32_array(pdev->dev.of_node, key,
462 smp2p->smem_items, 2);
463 if (ret)
464 return ret;
465
466 key = "qcom,local-pid";
467 ret = of_property_read_u32(pdev->dev.of_node, key, &smp2p->local_pid);
468 if (ret)
469 goto report_read_failure;
470
471 key = "qcom,remote-pid";
472 ret = of_property_read_u32(pdev->dev.of_node, key, &smp2p->remote_pid);
473 if (ret)
474 goto report_read_failure;
475
476 irq = platform_get_irq(pdev, 0);
477 if (irq < 0) {
478 dev_err(&pdev->dev, "unable to acquire smp2p interrupt\n");
479 return irq;
480 }
481
482 smp2p->mbox_client.dev = &pdev->dev;
483 smp2p->mbox_client.knows_txdone = true;
484 smp2p->mbox_chan = mbox_request_channel(&smp2p->mbox_client, 0);
485 if (IS_ERR(smp2p->mbox_chan)) {
486 if (PTR_ERR(smp2p->mbox_chan) != -ENODEV)
487 return PTR_ERR(smp2p->mbox_chan);
488
489 smp2p->mbox_chan = NULL;
490
491 ret = smp2p_parse_ipc(smp2p);
492 if (ret)
493 return ret;
494 }
495
496 ret = qcom_smp2p_alloc_outbound_item(smp2p);
497 if (ret < 0)
498 goto release_mbox;
499
500 for_each_available_child_of_node(pdev->dev.of_node, node) {
501 entry = devm_kzalloc(&pdev->dev, sizeof(*entry), GFP_KERNEL);
502 if (!entry) {
503 ret = -ENOMEM;
504 goto unwind_interfaces;
505 }
506
507 entry->smp2p = smp2p;
508 spin_lock_init(&entry->lock);
509
510 ret = of_property_read_string(node, "qcom,entry-name", &entry->name);
511 if (ret < 0)
512 goto unwind_interfaces;
513
514 if (of_property_read_bool(node, "interrupt-controller")) {
515 ret = qcom_smp2p_inbound_entry(smp2p, entry, node);
516 if (ret < 0)
517 goto unwind_interfaces;
518
519 list_add(&entry->node, &smp2p->inbound);
520 } else {
521 ret = qcom_smp2p_outbound_entry(smp2p, entry, node);
522 if (ret < 0)
523 goto unwind_interfaces;
524
525 list_add(&entry->node, &smp2p->outbound);
526 }
527 }
528
529 /* Kick the outgoing edge after allocating entries */
530 qcom_smp2p_kick(smp2p);
531
532 ret = devm_request_threaded_irq(&pdev->dev, irq,
533 NULL, qcom_smp2p_intr,
534 IRQF_ONESHOT,
535 "smp2p", (void *)smp2p);
536 if (ret) {
537 dev_err(&pdev->dev, "failed to request interrupt\n");
538 goto unwind_interfaces;
539 }
540
541
542 return 0;
543
544unwind_interfaces:
545 list_for_each_entry(entry, &smp2p->inbound, node)
546 irq_domain_remove(entry->domain);
547
548 list_for_each_entry(entry, &smp2p->outbound, node)
549 qcom_smem_state_unregister(entry->state);
550
551 smp2p->out->valid_entries = 0;
552
553release_mbox:
554 mbox_free_channel(smp2p->mbox_chan);
555
556 return ret;
557
558report_read_failure:
559 dev_err(&pdev->dev, "failed to read %s\n", key);
560 return -EINVAL;
561}
562
563static int qcom_smp2p_remove(struct platform_device *pdev)
564{
565 struct qcom_smp2p *smp2p = platform_get_drvdata(pdev);
566 struct smp2p_entry *entry;
567
568 list_for_each_entry(entry, &smp2p->inbound, node)
569 irq_domain_remove(entry->domain);
570
571 list_for_each_entry(entry, &smp2p->outbound, node)
572 qcom_smem_state_unregister(entry->state);
573
574 mbox_free_channel(smp2p->mbox_chan);
575
576 smp2p->out->valid_entries = 0;
577
578 return 0;
579}
580
581static const struct of_device_id qcom_smp2p_of_match[] = {
582 { .compatible = "qcom,smp2p" },
583 {}
584};
585MODULE_DEVICE_TABLE(of, qcom_smp2p_of_match);
586
587static struct platform_driver qcom_smp2p_driver = {
588 .probe = qcom_smp2p_probe,
589 .remove = qcom_smp2p_remove,
590 .driver = {
591 .name = "qcom_smp2p",
592 .of_match_table = qcom_smp2p_of_match,
593 },
594};
595module_platform_driver(qcom_smp2p_driver);
596
597MODULE_DESCRIPTION("Qualcomm Shared Memory Point to Point driver");
598MODULE_LICENSE("GPL v2");