qcom/smp2p.c

   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  */
  60 struct 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  */
  90 struct 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  */
 127 struct 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
 151 static 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  */
 172 static 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
 242 static 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
 250 static 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
 258 static 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
 279 static 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
 286 static 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
 300 static const struct irq_domain_ops smp2p_irq_ops = {
 301         .map = smp2p_irq_map,
 302         .xlate = irq_domain_xlate_twocell,
 303 };
 304
 305 static 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
 318 static int smp2p_update_bits(void *data, u32 mask, u32 value)
 319 {
 320         struct smp2p_entry *entry = data;
 321         unsigned long flags;
 322         u32 orig;
 323         u32 val;
 324
 325         spin_lock_irqsave(&entry->lock, flags);
 326         val = orig = readl(entry->value);
 327         val &= ~mask;
 328         val |= value;
 329         writel(val, entry->value);
 330         spin_unlock_irqrestore(&entry->lock, flags);
 331
 332         if (val != orig)
 333                 qcom_smp2p_kick(entry->smp2p);
 334
 335         return 0;
 336 }
 337
 338 static const struct qcom_smem_state_ops smp2p_state_ops = {
 339         .update_bits = smp2p_update_bits,
 340 };
 341
 342 static int qcom_smp2p_outbound_entry(struct qcom_smp2p *smp2p,
 343                                      struct smp2p_entry *entry,
 344                                      struct device_node *node)
 345 {
 346         struct smp2p_smem_item *out = smp2p->out;
 347         char buf[SMP2P_MAX_ENTRY_NAME] = {};
 348
 349         /* Allocate an entry from the smem item */
 350         strlcpy(buf, entry->name, SMP2P_MAX_ENTRY_NAME);
 351         memcpy(out->entries[out->valid_entries].name, buf, SMP2P_MAX_ENTRY_NAME);
 352
 353         /* Make the logical entry reference the physical value */
 354         entry->value = &out->entries[out->valid_entries].value;
 355
 356         out->valid_entries++;
 357
 358         entry->state = qcom_smem_state_register(node, &smp2p_state_ops, entry);
 359         if (IS_ERR(entry->state)) {
 360                 dev_err(smp2p->dev, "failed to register qcom_smem_state\n");
 361                 return PTR_ERR(entry->state);
 362         }
 363
 364         return 0;
 365 }
 366
 367 static int qcom_smp2p_alloc_outbound_item(struct qcom_smp2p *smp2p)
 368 {
 369         struct smp2p_smem_item *out;
 370         unsigned smem_id = smp2p->smem_items[SMP2P_OUTBOUND];
 371         unsigned pid = smp2p->remote_pid;
 372         int ret;
 373
 374         ret = qcom_smem_alloc(pid, smem_id, sizeof(*out));
 375         if (ret < 0 && ret != -EEXIST) {
 376                 if (ret != -EPROBE_DEFER)
 377                         dev_err(smp2p->dev,
 378                                 "unable to allocate local smp2p item\n");
 379                 return ret;
 380         }
 381
 382         out = qcom_smem_get(pid, smem_id, NULL);
 383         if (IS_ERR(out)) {
 384                 dev_err(smp2p->dev, "Unable to acquire local smp2p item\n");
 385                 return PTR_ERR(out);
 386         }
 387
 388         memset(out, 0, sizeof(*out));
 389         out->magic = SMP2P_MAGIC;
 390         out->local_pid = smp2p->local_pid;
 391         out->remote_pid = smp2p->remote_pid;
 392         out->total_entries = SMP2P_MAX_ENTRY;
 393         out->valid_entries = 0;
 394
 395         /*
 396          * Make sure the rest of the header is written before we validate the
 397          * item by writing a valid version number.
 398          */
 399         wmb();
 400         out->version = 1;
 401
 402         qcom_smp2p_kick(smp2p);
 403
 404         smp2p->out = out;
 405
 406         return 0;
 407 }
 408
 409 static int smp2p_parse_ipc(struct qcom_smp2p *smp2p)
 410 {
 411         struct device_node *syscon;
 412         struct device *dev = smp2p->dev;
 413         const char *key;
 414         int ret;
 415
 416         syscon = of_parse_phandle(dev->of_node, "qcom,ipc", 0);
 417         if (!syscon) {
 418                 dev_err(dev, "no qcom,ipc node\n");
 419                 return -ENODEV;
 420         }
 421
 422         smp2p->ipc_regmap = syscon_node_to_regmap(syscon);
 423         of_node_put(syscon);
 424         if (IS_ERR(smp2p->ipc_regmap))
 425                 return PTR_ERR(smp2p->ipc_regmap);
 426
 427         key = "qcom,ipc";
 428         ret = of_property_read_u32_index(dev->of_node, key, 1, &smp2p->ipc_offset);
 429         if (ret < 0) {
 430                 dev_err(dev, "no offset in %s\n", key);
 431                 return -EINVAL;
 432         }
 433
 434         ret = of_property_read_u32_index(dev->of_node, key, 2, &smp2p->ipc_bit);
 435         if (ret < 0) {
 436                 dev_err(dev, "no bit in %s\n", key);
 437                 return -EINVAL;
 438         }
 439
 440         return 0;
 441 }
 442
 443 static int qcom_smp2p_probe(struct platform_device *pdev)
 444 {
 445         struct smp2p_entry *entry;
 446         struct device_node *node;
 447         struct qcom_smp2p *smp2p;
 448         const char *key;
 449         int irq;
 450         int ret;
 451
 452         smp2p = devm_kzalloc(&pdev->dev, sizeof(*smp2p), GFP_KERNEL);
 453         if (!smp2p)
 454                 return -ENOMEM;
 455
 456         smp2p->dev = &pdev->dev;
 457         INIT_LIST_HEAD(&smp2p->inbound);
 458         INIT_LIST_HEAD(&smp2p->outbound);
 459
 460         platform_set_drvdata(pdev, smp2p);
 461
 462         key = "qcom,smem";
 463         ret = of_property_read_u32_array(pdev->dev.of_node, key,
 464                                          smp2p->smem_items, 2);
 465         if (ret)
 466                 return ret;
 467
 468         key = "qcom,local-pid";
 469         ret = of_property_read_u32(pdev->dev.of_node, key, &smp2p->local_pid);
 470         if (ret)
 471                 goto report_read_failure;
 472
 473         key = "qcom,remote-pid";
 474         ret = of_property_read_u32(pdev->dev.of_node, key, &smp2p->remote_pid);
 475         if (ret)
 476                 goto report_read_failure;
 477
 478         irq = platform_get_irq(pdev, 0);
 479         if (irq < 0)
 480                 return irq;
 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
 544 unwind_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
 553 release_mbox:
 554         mbox_free_channel(smp2p->mbox_chan);
 555
 556         return ret;
 557
 558 report_read_failure:
 559         dev_err(&pdev->dev, "failed to read %s\n", key);
 560         return -EINVAL;
 561 }
 562
 563 static 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
 581 static const struct of_device_id qcom_smp2p_of_match[] = {
 582         { .compatible = "qcom,smp2p" },
 583         {}
 584 };
 585 MODULE_DEVICE_TABLE(of, qcom_smp2p_of_match);
 586
 587 static 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 };
 595 module_platform_driver(qcom_smp2p_driver);
 596
 597 MODULE_DESCRIPTION("Qualcomm Shared Memory Point to Point driver");
 598 MODULE_LICENSE("GPL v2");