drivers/soc/qcom/smp2p.c

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