drivers/soc/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/pm_wakeirq.h>
  18 #include <linux/regmap.h>
  19 #include <linux/soc/qcom/smem.h>
  20 #include <linux/soc/qcom/smem_state.h>
  21 #include <linux/spinlock.h>
  22
  23 /*
  24  * The Shared Memory Point to Point (SMP2P) protocol facilitates communication
  25  * of a single 32-bit value between two processors.  Each value has a single
  26  * writer (the local side) and a single reader (the remote side). Values are
  27  * uniquely identified in the system by the directed edge (local processor ID
  28  * to remote processor ID) and a string identifier.
  29  *
  30  * Each processor is responsible for creating the outgoing SMEM items and each
  31  * item is writable by the local processor and readable by the remote
  32  * processor.  By using two separate SMEM items that are single-reader and
  33  * single-writer, SMP2P does not require any remote locking mechanisms.
  34  *
  35  * The driver uses the Linux GPIO and interrupt framework to expose a virtual
  36  * GPIO for each outbound entry and a virtual interrupt controller for each
  37  * inbound entry.
  38  */
  39
  40 #define SMP2P_MAX_ENTRY 16
  41 #define SMP2P_MAX_ENTRY_NAME 16
  42
  43 #define SMP2P_FEATURE_SSR_ACK 0x1
  44 #define SMP2P_FLAGS_RESTART_DONE_BIT 0
  45 #define SMP2P_FLAGS_RESTART_ACK_BIT 1
  46
  47 #define SMP2P_MAGIC 0x504d5324
  48 #define SMP2P_ALL_FEATURES      SMP2P_FEATURE_SSR_ACK
  49
  50 /**
  51  * struct smp2p_smem_item - in memory communication structure
  52  * @magic:              magic number
  53  * @version:            version - must be 1
  54  * @features:           features flag - currently unused
  55  * @local_pid:          processor id of sending end
  56  * @remote_pid:         processor id of receiving end
  57  * @total_entries:      number of entries - always SMP2P_MAX_ENTRY
  58  * @valid_entries:      number of allocated entries
  59  * @flags:
  60  * @entries:            individual communication entries
  61  *     @name:           name of the entry
  62  *     @value:          content of the entry
  63  */
  64 struct smp2p_smem_item {
  65         u32 magic;
  66         u8 version;
  67         unsigned features:24;
  68         u16 local_pid;
  69         u16 remote_pid;
  70         u16 total_entries;
  71         u16 valid_entries;
  72         u32 flags;
  73
  74         struct {
  75                 u8 name[SMP2P_MAX_ENTRY_NAME];
  76                 u32 value;
  77         } entries[SMP2P_MAX_ENTRY];
  78 } __packed;
  79
  80 /**
  81  * struct smp2p_entry - driver context matching one entry
  82  * @node:       list entry to keep track of allocated entries
  83  * @smp2p:      reference to the device driver context
  84  * @name:       name of the entry, to match against smp2p_smem_item
  85  * @value:      pointer to smp2p_smem_item entry value
  86  * @last_value: last handled value
  87  * @domain:     irq_domain for inbound entries
  88  * @irq_enabled:bitmap to track enabled irq bits
  89  * @irq_rising: bitmap to mark irq bits for rising detection
  90  * @irq_falling:bitmap to mark irq bits for falling detection
  91  * @state:      smem state handle
  92  * @lock:       spinlock to protect read-modify-write of the value
  93  */
  94 struct smp2p_entry {
  95         struct list_head node;
  96         struct qcom_smp2p *smp2p;
  97
  98         const char *name;
  99         u32 *value;
 100         u32 last_value;
 101
 102         struct irq_domain *domain;
 103         DECLARE_BITMAP(irq_enabled, 32);
 104         DECLARE_BITMAP(irq_rising, 32);
 105         DECLARE_BITMAP(irq_falling, 32);
 106
 107         struct qcom_smem_state *state;
 108
 109         spinlock_t lock;
 110 };
 111
 112 #define SMP2P_INBOUND   0
 113 #define SMP2P_OUTBOUND  1
 114
 115 /**
 116  * struct qcom_smp2p - device driver context
 117  * @dev:        device driver handle
 118  * @in:         pointer to the inbound smem item
 119  * @out:        pointer to the outbound smem item
 120  * @smem_items: ids of the two smem items
 121  * @valid_entries: already scanned inbound entries
 122  * @ssr_ack_enabled: SMP2P_FEATURE_SSR_ACK feature is supported and was enabled
 123  * @ssr_ack: current cached state of the local ack bit
 124  * @negotiation_done: whether negotiating finished
 125  * @local_pid:  processor id of the inbound edge
 126  * @remote_pid: processor id of the outbound edge
 127  * @ipc_regmap: regmap for the outbound ipc
 128  * @ipc_offset: offset within the regmap
 129  * @ipc_bit:    bit in regmap@offset to kick to signal remote processor
 130  * @mbox_client: mailbox client handle
 131  * @mbox_chan:  apcs ipc mailbox channel handle
 132  * @inbound:    list of inbound entries
 133  * @outbound:   list of outbound entries
 134  */
 135 struct qcom_smp2p {
 136         struct device *dev;
 137
 138         struct smp2p_smem_item *in;
 139         struct smp2p_smem_item *out;
 140
 141         unsigned smem_items[SMP2P_OUTBOUND + 1];
 142
 143         unsigned valid_entries;
 144
 145         bool ssr_ack_enabled;
 146         bool ssr_ack;
 147         bool negotiation_done;
 148
 149         unsigned local_pid;
 150         unsigned remote_pid;
 151
 152         struct regmap *ipc_regmap;
 153         int ipc_offset;
 154         int ipc_bit;
 155
 156         struct mbox_client mbox_client;
 157         struct mbox_chan *mbox_chan;
 158
 159         struct list_head inbound;
 160         struct list_head outbound;
 161 };
 162
 163 static void qcom_smp2p_kick(struct qcom_smp2p *smp2p)
 164 {
 165         /* Make sure any updated data is written before the kick */
 166         wmb();
 167
 168         if (smp2p->mbox_chan) {
 169                 mbox_send_message(smp2p->mbox_chan, NULL);
 170                 mbox_client_txdone(smp2p->mbox_chan, 0);
 171         } else {
 172                 regmap_write(smp2p->ipc_regmap, smp2p->ipc_offset, BIT(smp2p->ipc_bit));
 173         }
 174 }
 175
 176 static bool qcom_smp2p_check_ssr(struct qcom_smp2p *smp2p)
 177 {
 178         struct smp2p_smem_item *in = smp2p->in;
 179         bool restart;
 180
 181         if (!smp2p->ssr_ack_enabled)
 182                 return false;
 183
 184         restart = in->flags & BIT(SMP2P_FLAGS_RESTART_DONE_BIT);
 185
 186         return restart != smp2p->ssr_ack;
 187 }
 188
 189 static void qcom_smp2p_do_ssr_ack(struct qcom_smp2p *smp2p)
 190 {
 191         struct smp2p_smem_item *out = smp2p->out;
 192         u32 val;
 193
 194         smp2p->ssr_ack = !smp2p->ssr_ack;
 195
 196         val = out->flags & ~BIT(SMP2P_FLAGS_RESTART_ACK_BIT);
 197         if (smp2p->ssr_ack)
 198                 val |= BIT(SMP2P_FLAGS_RESTART_ACK_BIT);
 199         out->flags = val;
 200
 201         qcom_smp2p_kick(smp2p);
 202 }
 203
 204 static void qcom_smp2p_negotiate(struct qcom_smp2p *smp2p)
 205 {
 206         struct smp2p_smem_item *out = smp2p->out;
 207         struct smp2p_smem_item *in = smp2p->in;
 208
 209         if (in->version == out->version) {
 210                 out->features &= in->features;
 211
 212                 if (out->features & SMP2P_FEATURE_SSR_ACK)
 213                         smp2p->ssr_ack_enabled = true;
 214
 215                 smp2p->negotiation_done = true;
 216         }
 217 }
 218
 219 static void qcom_smp2p_notify_in(struct qcom_smp2p *smp2p)
 220 {
 221         struct smp2p_smem_item *in;
 222         struct smp2p_entry *entry;
 223         int irq_pin;
 224         u32 status;
 225         char buf[SMP2P_MAX_ENTRY_NAME];
 226         u32 val;
 227         int i;
 228
 229         in = smp2p->in;
 230
 231         /* Match newly created entries */
 232         for (i = smp2p->valid_entries; i < in->valid_entries; i++) {
 233                 list_for_each_entry(entry, &smp2p->inbound, node) {
 234                         memcpy(buf, in->entries[i].name, sizeof(buf));
 235                         if (!strcmp(buf, entry->name)) {
 236                                 entry->value = &in->entries[i].value;
 237                                 break;
 238                         }
 239                 }
 240         }
 241         smp2p->valid_entries = i;
 242
 243         /* Fire interrupts based on any value changes */
 244         list_for_each_entry(entry, &smp2p->inbound, node) {
 245                 /* Ignore entries not yet allocated by the remote side */
 246                 if (!entry->value)
 247                         continue;
 248
 249                 val = readl(entry->value);
 250
 251                 status = val ^ entry->last_value;
 252                 entry->last_value = val;
 253
 254                 /* No changes of this entry? */
 255                 if (!status)
 256                         continue;
 257
 258                 for_each_set_bit(i, entry->irq_enabled, 32) {
 259                         if (!(status & BIT(i)))
 260                                 continue;
 261
 262                         if ((val & BIT(i) && test_bit(i, entry->irq_rising)) ||
 263                             (!(val & BIT(i)) && test_bit(i, entry->irq_falling))) {
 264                                 irq_pin = irq_find_mapping(entry->domain, i);
 265                                 handle_nested_irq(irq_pin);
 266                         }
 267                 }
 268         }
 269 }
 270
 271 /**
 272  * qcom_smp2p_intr() - interrupt handler for incoming notifications
 273  * @irq:        unused
 274  * @data:       smp2p driver context
 275  *
 276  * Handle notifications from the remote side to handle newly allocated entries
 277  * or any changes to the state bits of existing entries.
 278  */
 279 static irqreturn_t qcom_smp2p_intr(int irq, void *data)
 280 {
 281         struct smp2p_smem_item *in;
 282         struct qcom_smp2p *smp2p = data;
 283         unsigned int smem_id = smp2p->smem_items[SMP2P_INBOUND];
 284         unsigned int pid = smp2p->remote_pid;
 285         bool ack_restart;
 286         size_t size;
 287
 288         in = smp2p->in;
 289
 290         /* Acquire smem item, if not already found */
 291         if (!in) {
 292                 in = qcom_smem_get(pid, smem_id, &size);
 293                 if (IS_ERR(in)) {
 294                         dev_err(smp2p->dev,
 295                                 "Unable to acquire remote smp2p item\n");
 296                         goto out;
 297                 }
 298
 299                 smp2p->in = in;
 300         }
 301
 302         if (!smp2p->negotiation_done)
 303                 qcom_smp2p_negotiate(smp2p);
 304
 305         if (smp2p->negotiation_done) {
 306                 ack_restart = qcom_smp2p_check_ssr(smp2p);
 307                 qcom_smp2p_notify_in(smp2p);
 308
 309                 if (ack_restart)
 310                         qcom_smp2p_do_ssr_ack(smp2p);
 311         }
 312
 313 out:
 314         return IRQ_HANDLED;
 315 }
 316
 317 static void smp2p_mask_irq(struct irq_data *irqd)
 318 {
 319         struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
 320         irq_hw_number_t irq = irqd_to_hwirq(irqd);
 321
 322         clear_bit(irq, entry->irq_enabled);
 323 }
 324
 325 static void smp2p_unmask_irq(struct irq_data *irqd)
 326 {
 327         struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
 328         irq_hw_number_t irq = irqd_to_hwirq(irqd);
 329
 330         set_bit(irq, entry->irq_enabled);
 331 }
 332
 333 static int smp2p_set_irq_type(struct irq_data *irqd, unsigned int type)
 334 {
 335         struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
 336         irq_hw_number_t irq = irqd_to_hwirq(irqd);
 337
 338         if (!(type & IRQ_TYPE_EDGE_BOTH))
 339                 return -EINVAL;
 340
 341         if (type & IRQ_TYPE_EDGE_RISING)
 342                 set_bit(irq, entry->irq_rising);
 343         else
 344                 clear_bit(irq, entry->irq_rising);
 345
 346         if (type & IRQ_TYPE_EDGE_FALLING)
 347                 set_bit(irq, entry->irq_falling);
 348         else
 349                 clear_bit(irq, entry->irq_falling);
 350
 351         return 0;
 352 }
 353
 354 static struct irq_chip smp2p_irq_chip = {
 355         .name           = "smp2p",
 356         .irq_mask       = smp2p_mask_irq,
 357         .irq_unmask     = smp2p_unmask_irq,
 358         .irq_set_type   = smp2p_set_irq_type,
 359 };
 360
 361 static int smp2p_irq_map(struct irq_domain *d,
 362                          unsigned int irq,
 363                          irq_hw_number_t hw)
 364 {
 365         struct smp2p_entry *entry = d->host_data;
 366
 367         irq_set_chip_and_handler(irq, &smp2p_irq_chip, handle_level_irq);
 368         irq_set_chip_data(irq, entry);
 369         irq_set_nested_thread(irq, 1);
 370         irq_set_noprobe(irq);
 371
 372         return 0;
 373 }
 374
 375 static const struct irq_domain_ops smp2p_irq_ops = {
 376         .map = smp2p_irq_map,
 377         .xlate = irq_domain_xlate_twocell,
 378 };
 379
 380 static int qcom_smp2p_inbound_entry(struct qcom_smp2p *smp2p,
 381                                     struct smp2p_entry *entry,
 382                                     struct device_node *node)
 383 {
 384         entry->domain = irq_domain_add_linear(node, 32, &smp2p_irq_ops, entry);
 385         if (!entry->domain) {
 386                 dev_err(smp2p->dev, "failed to add irq_domain\n");
 387                 return -ENOMEM;
 388         }
 389
 390         return 0;
 391 }
 392
 393 static int smp2p_update_bits(void *data, u32 mask, u32 value)
 394 {
 395         struct smp2p_entry *entry = data;
 396         unsigned long flags;
 397         u32 orig;
 398         u32 val;
 399
 400         spin_lock_irqsave(&entry->lock, flags);
 401         val = orig = readl(entry->value);
 402         val &= ~mask;
 403         val |= value;
 404         writel(val, entry->value);
 405         spin_unlock_irqrestore(&entry->lock, flags);
 406
 407         if (val != orig)
 408                 qcom_smp2p_kick(entry->smp2p);
 409
 410         return 0;
 411 }
 412
 413 static const struct qcom_smem_state_ops smp2p_state_ops = {
 414         .update_bits = smp2p_update_bits,
 415 };
 416
 417 static int qcom_smp2p_outbound_entry(struct qcom_smp2p *smp2p,
 418                                      struct smp2p_entry *entry,
 419                                      struct device_node *node)
 420 {
 421         struct smp2p_smem_item *out = smp2p->out;
 422         char buf[SMP2P_MAX_ENTRY_NAME] = {};
 423
 424         /* Allocate an entry from the smem item */
 425         strscpy(buf, entry->name, SMP2P_MAX_ENTRY_NAME);
 426         memcpy(out->entries[out->valid_entries].name, buf, SMP2P_MAX_ENTRY_NAME);
 427
 428         /* Make the logical entry reference the physical value */
 429         entry->value = &out->entries[out->valid_entries].value;
 430
 431         out->valid_entries++;
 432
 433         entry->state = qcom_smem_state_register(node, &smp2p_state_ops, entry);
 434         if (IS_ERR(entry->state)) {
 435                 dev_err(smp2p->dev, "failed to register qcom_smem_state\n");
 436                 return PTR_ERR(entry->state);
 437         }
 438
 439         return 0;
 440 }
 441
 442 static int qcom_smp2p_alloc_outbound_item(struct qcom_smp2p *smp2p)
 443 {
 444         struct smp2p_smem_item *out;
 445         unsigned smem_id = smp2p->smem_items[SMP2P_OUTBOUND];
 446         unsigned pid = smp2p->remote_pid;
 447         int ret;
 448
 449         ret = qcom_smem_alloc(pid, smem_id, sizeof(*out));
 450         if (ret < 0 && ret != -EEXIST) {
 451                 if (ret != -EPROBE_DEFER)
 452                         dev_err(smp2p->dev,
 453                                 "unable to allocate local smp2p item\n");
 454                 return ret;
 455         }
 456
 457         out = qcom_smem_get(pid, smem_id, NULL);
 458         if (IS_ERR(out)) {
 459                 dev_err(smp2p->dev, "Unable to acquire local smp2p item\n");
 460                 return PTR_ERR(out);
 461         }
 462
 463         memset(out, 0, sizeof(*out));
 464         out->magic = SMP2P_MAGIC;
 465         out->local_pid = smp2p->local_pid;
 466         out->remote_pid = smp2p->remote_pid;
 467         out->total_entries = SMP2P_MAX_ENTRY;
 468         out->valid_entries = 0;
 469         out->features = SMP2P_ALL_FEATURES;
 470
 471         /*
 472          * Make sure the rest of the header is written before we validate the
 473          * item by writing a valid version number.
 474          */
 475         wmb();
 476         out->version = 1;
 477
 478         qcom_smp2p_kick(smp2p);
 479
 480         smp2p->out = out;
 481
 482         return 0;
 483 }
 484
 485 static int smp2p_parse_ipc(struct qcom_smp2p *smp2p)
 486 {
 487         struct device_node *syscon;
 488         struct device *dev = smp2p->dev;
 489         const char *key;
 490         int ret;
 491
 492         syscon = of_parse_phandle(dev->of_node, "qcom,ipc", 0);
 493         if (!syscon) {
 494                 dev_err(dev, "no qcom,ipc node\n");
 495                 return -ENODEV;
 496         }
 497
 498         smp2p->ipc_regmap = syscon_node_to_regmap(syscon);
 499         of_node_put(syscon);
 500         if (IS_ERR(smp2p->ipc_regmap))
 501                 return PTR_ERR(smp2p->ipc_regmap);
 502
 503         key = "qcom,ipc";
 504         ret = of_property_read_u32_index(dev->of_node, key, 1, &smp2p->ipc_offset);
 505         if (ret < 0) {
 506                 dev_err(dev, "no offset in %s\n", key);
 507                 return -EINVAL;
 508         }
 509
 510         ret = of_property_read_u32_index(dev->of_node, key, 2, &smp2p->ipc_bit);
 511         if (ret < 0) {
 512                 dev_err(dev, "no bit in %s\n", key);
 513                 return -EINVAL;
 514         }
 515
 516         return 0;
 517 }
 518
 519 static int qcom_smp2p_probe(struct platform_device *pdev)
 520 {
 521         struct smp2p_entry *entry;
 522         struct device_node *node;
 523         struct qcom_smp2p *smp2p;
 524         const char *key;
 525         int irq;
 526         int ret;
 527
 528         smp2p = devm_kzalloc(&pdev->dev, sizeof(*smp2p), GFP_KERNEL);
 529         if (!smp2p)
 530                 return -ENOMEM;
 531
 532         smp2p->dev = &pdev->dev;
 533         INIT_LIST_HEAD(&smp2p->inbound);
 534         INIT_LIST_HEAD(&smp2p->outbound);
 535
 536         platform_set_drvdata(pdev, smp2p);
 537
 538         key = "qcom,smem";
 539         ret = of_property_read_u32_array(pdev->dev.of_node, key,
 540                                          smp2p->smem_items, 2);
 541         if (ret)
 542                 return ret;
 543
 544         key = "qcom,local-pid";
 545         ret = of_property_read_u32(pdev->dev.of_node, key, &smp2p->local_pid);
 546         if (ret)
 547                 goto report_read_failure;
 548
 549         key = "qcom,remote-pid";
 550         ret = of_property_read_u32(pdev->dev.of_node, key, &smp2p->remote_pid);
 551         if (ret)
 552                 goto report_read_failure;
 553
 554         irq = platform_get_irq(pdev, 0);
 555         if (irq < 0)
 556                 return irq;
 557
 558         smp2p->mbox_client.dev = &pdev->dev;
 559         smp2p->mbox_client.knows_txdone = true;
 560         smp2p->mbox_chan = mbox_request_channel(&smp2p->mbox_client, 0);
 561         if (IS_ERR(smp2p->mbox_chan)) {
 562                 if (PTR_ERR(smp2p->mbox_chan) != -ENODEV)
 563                         return PTR_ERR(smp2p->mbox_chan);
 564
 565                 smp2p->mbox_chan = NULL;
 566
 567                 ret = smp2p_parse_ipc(smp2p);
 568                 if (ret)
 569                         return ret;
 570         }
 571
 572         ret = qcom_smp2p_alloc_outbound_item(smp2p);
 573         if (ret < 0)
 574                 goto release_mbox;
 575
 576         for_each_available_child_of_node(pdev->dev.of_node, node) {
 577                 entry = devm_kzalloc(&pdev->dev, sizeof(*entry), GFP_KERNEL);
 578                 if (!entry) {
 579                         ret = -ENOMEM;
 580                         of_node_put(node);
 581                         goto unwind_interfaces;
 582                 }
 583
 584                 entry->smp2p = smp2p;
 585                 spin_lock_init(&entry->lock);
 586
 587                 ret = of_property_read_string(node, "qcom,entry-name", &entry->name);
 588                 if (ret < 0) {
 589                         of_node_put(node);
 590                         goto unwind_interfaces;
 591                 }
 592
 593                 if (of_property_read_bool(node, "interrupt-controller")) {
 594                         ret = qcom_smp2p_inbound_entry(smp2p, entry, node);
 595                         if (ret < 0) {
 596                                 of_node_put(node);
 597                                 goto unwind_interfaces;
 598                         }
 599
 600                         list_add(&entry->node, &smp2p->inbound);
 601                 } else  {
 602                         ret = qcom_smp2p_outbound_entry(smp2p, entry, node);
 603                         if (ret < 0) {
 604                                 of_node_put(node);
 605                                 goto unwind_interfaces;
 606                         }
 607
 608                         list_add(&entry->node, &smp2p->outbound);
 609                 }
 610         }
 611
 612         /* Kick the outgoing edge after allocating entries */
 613         qcom_smp2p_kick(smp2p);
 614
 615         ret = devm_request_threaded_irq(&pdev->dev, irq,
 616                                         NULL, qcom_smp2p_intr,
 617                                         IRQF_ONESHOT,
 618                                         "smp2p", (void *)smp2p);
 619         if (ret) {
 620                 dev_err(&pdev->dev, "failed to request interrupt\n");
 621                 goto unwind_interfaces;
 622         }
 623
 624         /*
 625          * Treat smp2p interrupt as wakeup source, but keep it disabled
 626          * by default. User space can decide enabling it depending on its
 627          * use cases. For example if remoteproc crashes and device wants
 628          * to handle it immediatedly (e.g. to not miss phone calls) it can
 629          * enable wakeup source from user space, while other devices which
 630          * do not have proper autosleep feature may want to handle it with
 631          * other wakeup events (e.g. Power button) instead waking up immediately.
 632          */
 633         device_set_wakeup_capable(&pdev->dev, true);
 634
 635         ret = dev_pm_set_wake_irq(&pdev->dev, irq);
 636         if (ret)
 637                 goto set_wake_irq_fail;
 638
 639         return 0;
 640
 641 set_wake_irq_fail:
 642         dev_pm_clear_wake_irq(&pdev->dev);
 643
 644 unwind_interfaces:
 645         list_for_each_entry(entry, &smp2p->inbound, node)
 646                 irq_domain_remove(entry->domain);
 647
 648         list_for_each_entry(entry, &smp2p->outbound, node)
 649                 qcom_smem_state_unregister(entry->state);
 650
 651         smp2p->out->valid_entries = 0;
 652
 653 release_mbox:
 654         mbox_free_channel(smp2p->mbox_chan);
 655
 656         return ret;
 657
 658 report_read_failure:
 659         dev_err(&pdev->dev, "failed to read %s\n", key);
 660         return -EINVAL;
 661 }
 662
 663 static int qcom_smp2p_remove(struct platform_device *pdev)
 664 {
 665         struct qcom_smp2p *smp2p = platform_get_drvdata(pdev);
 666         struct smp2p_entry *entry;
 667
 668         dev_pm_clear_wake_irq(&pdev->dev);
 669
 670         list_for_each_entry(entry, &smp2p->inbound, node)
 671                 irq_domain_remove(entry->domain);
 672
 673         list_for_each_entry(entry, &smp2p->outbound, node)
 674                 qcom_smem_state_unregister(entry->state);
 675
 676         mbox_free_channel(smp2p->mbox_chan);
 677
 678         smp2p->out->valid_entries = 0;
 679
 680         return 0;
 681 }
 682
 683 static const struct of_device_id qcom_smp2p_of_match[] = {
 684         { .compatible = "qcom,smp2p" },
 685         {}
 686 };
 687 MODULE_DEVICE_TABLE(of, qcom_smp2p_of_match);
 688
 689 static struct platform_driver qcom_smp2p_driver = {
 690         .probe = qcom_smp2p_probe,
 691         .remove = qcom_smp2p_remove,
 692         .driver  = {
 693                 .name  = "qcom_smp2p",
 694                 .of_match_table = qcom_smp2p_of_match,
 695         },
 696 };
 697 module_platform_driver(qcom_smp2p_driver);
 698
 699 MODULE_DESCRIPTION("Qualcomm Shared Memory Point to Point driver");
 700 MODULE_LICENSE("GPL v2");