drivers/gpio/gpio-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/module.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/of_platform.h>
  18 #include <linux/io.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/memblock.h>
  21 #include <linux/slab.h>
  22 #include <linux/of_address.h>
  23 #include <linux/of_irq.h>
  24 #include <linux/regmap.h>
  25 #include <linux/list.h>
  26 #include <linux/gpio.h>
  27 #include <linux/mfd/syscon.h>
  28
  29 #include <linux/delay.h>
  30
  31 #include <linux/soc/qcom/smem.h>
  32
  33 /*
  34  * The Shared Memory Point to Point (SMP2P) protocol facilitates communication
  35  * of a single 32-bit value between two processors.  Each value has a single
  36  * writer (the local side) and a single reader (the remote side). Values are
  37  * uniquely identified in the system by the directed edge (local processor ID
  38  * to remote processor ID) and a string identifier.
  39  *
  40  * Each processor is responsible for creating the outgoing SMEM items and each
  41  * item is writable by the local processor and readable by the remote
  42  * processor.  By using two separate SMEM items that are single-reader and
  43  * single-writer, SMP2P does not require any remote locking mechanisms.
  44  *
  45  * The driver uses the Linux GPIO and interrupt framework to expose a virtual
  46  * GPIO for each outbound entry and a virtual interrupt controller for each
  47  * inbound entry.
  48  */
  49
  50 #define SMP2P_MAX_ENTRY 16
  51 #define SMP2P_MAX_ENTRY_NAME 16
  52
  53 #define SMP2P_FEATURE_SSR_ACK 0x1
  54
  55 #define SMP2P_MAGIC 0x504d5324
  56
  57 /**
  58  * struct smp2p_smem_item - in memory communication structure
  59  * @magic:              magic number
  60  * @version:            version - must be 1
  61  * @features:           features flag - currently unused
  62  * @local_pid:          processor id of sending end
  63  * @remote_pid:         processor id of receiving end
  64  * @total_entries:      number of entries - always SMP2P_MAX_ENTRY
  65  * @valid_entries:      number of allocated entries
  66  * @flags:
  67  * @entries:            individual communication entries
  68  *     @name:           name of the entry
  69  *     @value:          content of the entry
  70  */
  71 struct smp2p_smem_item {
  72         u32 magic;
  73         u8 version;
  74         unsigned features:24;
  75         u16 local_pid;
  76         u16 remote_pid;
  77         u16 total_entries;
  78         u16 valid_entries;
  79         u32 flags;
  80
  81         struct {
  82                 u8 name[SMP2P_MAX_ENTRY_NAME];
  83                 u32 value;
  84         } entries[SMP2P_MAX_ENTRY];
  85 } __packed;
  86
  87 /**
  88  * struct smp2p_entry - driver context matching one entry
  89  * @node:       list entry to keep track of allocated entries
  90  * @smp2p:      reference to the device driver context
  91  * @name:       name of the entry, to match against smp2p_smem_item
  92  * @value:      pointer to smp2p_smem_item entry value
  93  * @last_value: last handled value
  94  * @domain:     irq_domain for inbound entries
  95  * @irq_enabled:bitmap to track enabled irq bits
  96  * @irq_rising: bitmap to mark irq bits for rising detection
  97  * @irq_falling:bitmap to mark irq bits for falling detection
  98  * @chip:       gpio_chip for outbound entries
  99  */
 100 struct smp2p_entry {
 101         struct list_head node;
 102         struct qcom_smp2p *smp2p;
 103
 104         const char *name;
 105         u32 *value;
 106         u32 last_value;
 107
 108         struct irq_domain *domain;
 109         DECLARE_BITMAP(irq_enabled, 32);
 110         DECLARE_BITMAP(irq_rising, 32);
 111         DECLARE_BITMAP(irq_falling, 32);
 112
 113         struct gpio_chip chip;
 114 };
 115
 116 #define SMP2P_INBOUND   0
 117 #define SMP2P_OUTBOUND  1
 118
 119 /**
 120  * struct qcom_smp2p - device driver context
 121  * @dev:        device driver handle
 122  * @in:         pointer to the inbound smem item
 123  * @smem_items: ids of the two smem items
 124  * @valid_entries: already scanned inbound entries
 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  * @inbound:    list of inbound entries
 131  * @outbound:   list of outbound entries
 132  */
 133 struct qcom_smp2p {
 134         struct device *dev;
 135
 136         struct smp2p_smem_item *in;
 137         struct smp2p_smem_item *out;
 138
 139         unsigned smem_items[SMP2P_OUTBOUND + 1];
 140
 141         unsigned valid_entries;
 142
 143         unsigned local_pid;
 144         unsigned remote_pid;
 145
 146         struct regmap *ipc_regmap;
 147         int ipc_offset;
 148         int ipc_bit;
 149
 150         struct list_head inbound;
 151         struct list_head outbound;
 152 };
 153
 154 static void qcom_smp2p_kick(struct qcom_smp2p *smp2p)
 155 {
 156         /* Make sure any updated data is written before the kick */
 157         wmb();
 158         regmap_write(smp2p->ipc_regmap, smp2p->ipc_offset, BIT(smp2p->ipc_bit));
 159 }
 160
 161 static irqreturn_t qcom_smp2p_intr(int irq, void *data)
 162 {
 163         struct smp2p_smem_item *in;
 164         struct smp2p_entry *entry;
 165         struct qcom_smp2p *smp2p = data;
 166         unsigned smem_id = smp2p->smem_items[SMP2P_INBOUND];
 167         unsigned pid = smp2p->remote_pid;
 168         size_t size;
 169         int irq_pin;
 170         u32 status;
 171         u32 val;
 172         int i;
 173         u8 tmp_name[SMP2P_MAX_ENTRY_NAME];
 174
 175         in = smp2p->in;
 176
 177         /* Acquire smem item, if not already found */
 178         if (!in) {
 179                 in = qcom_smem_get(pid, smem_id, &size);
 180                 if (IS_ERR(in)) {
 181                         dev_err(smp2p->dev,
 182                                         "Unable to acquire remote smp2p item\n");
 183                         return IRQ_HANDLED;
 184                 }
 185
 186                 smp2p->in = in;
 187         }
 188
 189         /* Match newly created entries */
 190         for (i = smp2p->valid_entries; i < in->valid_entries; i++) {
 191                 list_for_each_entry(entry, &smp2p->inbound, node) {
 192                         memcpy_fromio(tmp_name, in->entries[i].name,
 193                                         SMP2P_MAX_ENTRY_NAME);
 194                         if (!strcmp(tmp_name, entry->name)) {
 195                                 entry->value = &in->entries[i].value;
 196                                 break;
 197                         }
 198                 }
 199         }
 200         smp2p->valid_entries = i;
 201
 202         /* Fire interrupts based on any value changes */
 203         list_for_each_entry(entry, &smp2p->inbound, node) {
 204                 /* Ignore entries not yet allocated by the remote side */
 205                 if (!entry->value)
 206                         continue;
 207
 208                 val = *entry->value;
 209
 210                 status = val ^ entry->last_value;
 211                 entry->last_value = val;
 212
 213                 /* No changes of this entry? */
 214                 if (!status)
 215                         continue;
 216
 217                 for_each_set_bit(i, entry->irq_enabled, 32) {
 218                         if (!(status & BIT(i)))
 219                                 continue;
 220
 221                         if (val & BIT(i)) {
 222                                 if (test_bit(i, entry->irq_rising)) {
 223                                         irq_pin = irq_find_mapping(entry->domain, i);
 224                                         handle_nested_irq(irq_pin);
 225                                 }
 226                         } else {
 227                                 if (test_bit(i, entry->irq_falling)) {
 228                                         irq_pin = irq_find_mapping(entry->domain, i);
 229                                         handle_nested_irq(irq_pin);
 230                                 }
 231                         }
 232
 233                 }
 234         }
 235
 236         return IRQ_HANDLED;
 237 }
 238
 239 static void smp2p_mask_irq(struct irq_data *irqd)
 240 {
 241         struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
 242         irq_hw_number_t irq = irqd_to_hwirq(irqd);
 243
 244         clear_bit(irq, entry->irq_enabled);
 245 }
 246
 247 static void smp2p_unmask_irq(struct irq_data *irqd)
 248 {
 249         struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
 250         irq_hw_number_t irq = irqd_to_hwirq(irqd);
 251
 252         set_bit(irq, entry->irq_enabled);
 253 }
 254
 255 static int smp2p_set_irq_type(struct irq_data *irqd, unsigned int type)
 256 {
 257         struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
 258         irq_hw_number_t irq = irqd_to_hwirq(irqd);
 259
 260         if (!(type & IRQ_TYPE_EDGE_BOTH))
 261                 return -EINVAL;
 262
 263         if (type & IRQ_TYPE_EDGE_RISING)
 264                 set_bit(irq, entry->irq_rising);
 265         else
 266                 clear_bit(irq, entry->irq_rising);
 267
 268         if (type & IRQ_TYPE_EDGE_FALLING)
 269                 set_bit(irq, entry->irq_falling);
 270         else
 271                 clear_bit(irq, entry->irq_falling);
 272
 273         return 0;
 274 }
 275
 276 static struct irq_chip smp2p_irq_chip = {
 277         .name           = "smp2p",
 278         .irq_mask       = smp2p_mask_irq,
 279         .irq_unmask     = smp2p_unmask_irq,
 280         .irq_set_type   = smp2p_set_irq_type,
 281 };
 282
 283 static int smp2p_irq_map(struct irq_domain *d,
 284                          unsigned int irq,
 285                          irq_hw_number_t hw)
 286 {
 287         struct smp2p_entry *entry = d->host_data;
 288
 289         irq_set_chip_and_handler(irq, &smp2p_irq_chip, handle_level_irq);
 290         irq_set_chip_data(irq, entry);
 291         irq_set_nested_thread(irq, 1);
 292
 293         irq_set_noprobe(irq);
 294
 295         return 0;
 296 }
 297
 298 static const struct irq_domain_ops smp2p_irq_ops = {
 299         .map = smp2p_irq_map,
 300         .xlate = irq_domain_xlate_twocell,
 301 };
 302
 303 static int smp2p_gpio_direction_output(struct gpio_chip *chip,
 304                                        unsigned offset,
 305                                        int value)
 306 {
 307         struct smp2p_entry *entry = container_of(chip, struct smp2p_entry, chip);
 308
 309         if (value)
 310                 *entry->value |= BIT(offset);
 311         else
 312                 *entry->value &= ~BIT(offset);
 313
 314         qcom_smp2p_kick(entry->smp2p);
 315
 316         return 0;
 317 }
 318
 319 static void smp2p_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 320 {
 321         smp2p_gpio_direction_output(chip, offset, value);
 322 }
 323
 324 static int qcom_smp2p_inbound_entry(struct qcom_smp2p *smp2p,
 325                                     struct smp2p_entry *entry,
 326                                     struct device_node *node)
 327 {
 328         entry->domain = irq_domain_add_linear(node, 32, &smp2p_irq_ops, entry);
 329         if (!entry->domain) {
 330                 dev_err(smp2p->dev, "failed to add irq_domain\n");
 331                 return -ENOMEM;
 332         }
 333
 334         return 0;
 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         struct gpio_chip *chip;
 343         int ret;
 344
 345         /* Allocate an entry from the smem item */
 346         memcpy_toio(out->entries[out->valid_entries].name, entry->name, SMP2P_MAX_ENTRY_NAME);
 347         out->valid_entries++;
 348
 349         /* Make the logical entry reference the physical value */
 350         entry->value = &out->entries[out->valid_entries].value;
 351
 352         chip = &entry->chip;
 353         chip->base = -1;
 354         chip->ngpio = 32;
 355         chip->label = entry->name;
 356         chip->dev = smp2p->dev;
 357         chip->owner = THIS_MODULE;
 358         chip->of_node = node;
 359
 360         chip->set = smp2p_gpio_set;
 361         chip->direction_output = smp2p_gpio_direction_output;
 362
 363         ret = gpiochip_add(chip);
 364         if (ret)
 365                 dev_err(smp2p->dev, "failed register gpiochip\n");
 366
 367         return 0;
 368 }
 369
 370 static int qcom_smp2p_alloc_outbound_item(struct qcom_smp2p *smp2p)
 371 {
 372         struct smp2p_smem_item *out;
 373         unsigned smem_id = smp2p->smem_items[SMP2P_OUTBOUND];
 374         unsigned pid = smp2p->remote_pid;
 375         int ret;
 376
 377         ret = qcom_smem_alloc(pid, smem_id, sizeof(*out));
 378         if (ret < 0 && ret != -EEXIST) {
 379                 if (ret != -EPROBE_DEFER)
 380                         dev_err(smp2p->dev,
 381                                 "unable to allocate local smp2p item\n");
 382                 return ret;
 383         }
 384
 385         out = qcom_smem_get(pid, smem_id, NULL);
 386         if (IS_ERR(out)) {
 387                 dev_err(smp2p->dev, "Unable to acquire local smp2p item\n");
 388                 return PTR_ERR(out);
 389         }
 390
 391         memset_io(out, 0, sizeof(*out));
 392         out->magic = SMP2P_MAGIC;
 393         out->local_pid = smp2p->local_pid;
 394         out->remote_pid = smp2p->remote_pid;
 395         out->total_entries = SMP2P_MAX_ENTRY;
 396         out->valid_entries = 0;
 397
 398         /*
 399          * Make sure the rest of the header is written before we validate the
 400          * item by writing a valid version number.
 401          */
 402         wmb();
 403         out->version = 1;
 404
 405         qcom_smp2p_kick(smp2p);
 406
 407         smp2p->out = out;
 408
 409         return 0;
 410 }
 411
 412 static int smp2p_parse_ipc(struct qcom_smp2p *smp2p)
 413 {
 414         struct device_node *syscon;
 415         struct device *dev = smp2p->dev;
 416         const char *key;
 417         int ret;
 418
 419         syscon = of_parse_phandle(dev->of_node, "qcom,ipc", 0);
 420         if (!syscon) {
 421                 dev_err(dev, "no qcom,ipc node\n");
 422                 return -ENODEV;
 423         }
 424
 425         smp2p->ipc_regmap = syscon_node_to_regmap(syscon);
 426         if (IS_ERR(smp2p->ipc_regmap))
 427                 return PTR_ERR(smp2p->ipc_regmap);
 428
 429         key = "qcom,ipc";
 430         ret = of_property_read_u32_index(dev->of_node, key, 1, &smp2p->ipc_offset);
 431         if (ret < 0) {
 432                 dev_err(dev, "no offset in %s\n", key);
 433                 return -EINVAL;
 434         }
 435
 436         ret = of_property_read_u32_index(dev->of_node, key, 2, &smp2p->ipc_bit);
 437         if (ret < 0) {
 438                 dev_err(dev, "no bit in %s\n", key);
 439                 return -EINVAL;
 440         }
 441
 442         return 0;
 443 }
 444
 445 static int qcom_smp2p_probe(struct platform_device *pdev)
 446 {
 447         struct smp2p_entry *entry;
 448         struct device_node *node;
 449         struct qcom_smp2p *smp2p;
 450         const char *key;
 451         int irq;
 452         int ret;
 453
 454         smp2p = devm_kzalloc(&pdev->dev, sizeof(*smp2p), GFP_KERNEL);
 455         if (!smp2p)
 456                 return -ENOMEM;
 457
 458         smp2p->dev = &pdev->dev;
 459         INIT_LIST_HEAD(&smp2p->inbound);
 460         INIT_LIST_HEAD(&smp2p->outbound);
 461
 462         platform_set_drvdata(pdev, smp2p);
 463
 464         ret = smp2p_parse_ipc(smp2p);
 465         if (ret)
 466                 return ret;
 467
 468         key = "qcom,smem";
 469         ret = of_property_read_u32_array(pdev->dev.of_node, key,
 470                                          smp2p->smem_items, 2);
 471         if (ret)
 472                 return ret;
 473
 474         key = "qcom,local-pid";
 475         ret = of_property_read_u32(pdev->dev.of_node, key, &smp2p->local_pid);
 476         if (ret < 0) {
 477                 dev_err(&pdev->dev, "failed to read %s\n", key);
 478                 return -EINVAL;
 479         }
 480
 481         key = "qcom,remote-pid";
 482         ret = of_property_read_u32(pdev->dev.of_node, key, &smp2p->remote_pid);
 483         if (ret < 0) {
 484                 dev_err(&pdev->dev, "failed to read %s\n", key);
 485                 return -EINVAL;
 486         }
 487
 488         irq = platform_get_irq(pdev, 0);
 489         if (irq < 0) {
 490                 dev_err(&pdev->dev, "unable to acquire smp2p interrupt\n");
 491                 return irq;
 492         }
 493
 494         ret = qcom_smp2p_alloc_outbound_item(smp2p);
 495         if (ret < 0)
 496                 return ret;
 497
 498         for_each_available_child_of_node(pdev->dev.of_node, node) {
 499                 entry = devm_kzalloc(&pdev->dev, sizeof(*entry), GFP_KERNEL);
 500                 if (!entry) {
 501                         ret = -ENOMEM;
 502                         goto unwind_interfaces;
 503                 }
 504
 505                 entry->smp2p = smp2p;
 506
 507                 ret = of_property_read_string(node, "qcom,entry-name", &entry->name);
 508                 if (ret < 0)
 509                         goto unwind_interfaces;
 510
 511                 if (of_property_read_bool(node, "qcom,inbound")) {
 512                         ret = qcom_smp2p_inbound_entry(smp2p, entry, node);
 513                         if (ret < 0)
 514                                 goto unwind_interfaces;
 515
 516                         list_add(&entry->node, &smp2p->inbound);
 517                 } else if (of_property_read_bool(node, "qcom,outbound")) {
 518                         ret = qcom_smp2p_outbound_entry(smp2p, entry, node);
 519                         if (ret < 0)
 520                                 goto unwind_interfaces;
 521
 522                         list_add(&entry->node, &smp2p->outbound);
 523                 } else {
 524                         dev_err(&pdev->dev, "neither inbound nor outbound\n");
 525                         ret = -EINVAL;
 526                         goto unwind_interfaces;
 527                 }
 528         }
 529
 530         /* Kick the outgoing edge after allocating entries */
 531         qcom_smp2p_kick(smp2p);
 532
 533         ret = devm_request_threaded_irq(&pdev->dev, irq,
 534                                         NULL, qcom_smp2p_intr,
 535                                         IRQF_ONESHOT,
 536                                         "smp2p", (void *)smp2p);
 537         if (ret) {
 538                 dev_err(&pdev->dev, "failed to request interrupt\n");
 539                 goto unwind_interfaces;
 540         }
 541
 542
 543         return 0;
 544
 545 unwind_interfaces:
 546         list_for_each_entry(entry, &smp2p->inbound, node)
 547                 irq_domain_remove(entry->domain);
 548
 549         list_for_each_entry(entry, &smp2p->outbound, node)
 550                 gpiochip_remove(&entry->chip);
 551
 552         smp2p->out->valid_entries = 0;
 553
 554         return ret;
 555 }
 556
 557 static int qcom_smp2p_remove(struct platform_device *pdev)
 558 {
 559         struct qcom_smp2p *smp2p = platform_get_drvdata(pdev);
 560         struct smp2p_entry *entry;
 561
 562         list_for_each_entry(entry, &smp2p->inbound, node)
 563                 irq_domain_remove(entry->domain);
 564
 565         list_for_each_entry(entry, &smp2p->outbound, node)
 566                 gpiochip_remove(&entry->chip);
 567
 568         smp2p->out->valid_entries = 0;
 569
 570         return 0;
 571 }
 572
 573 static const struct of_device_id qcom_smp2p_of_match[] = {
 574         { .compatible = "qcom,smp2p" },
 575         {}
 576 };
 577 MODULE_DEVICE_TABLE(of, qcom_smp2p_of_match);
 578
 579 static struct platform_driver qcom_smp2p_driver = {
 580         .probe = qcom_smp2p_probe,
 581         .remove = qcom_smp2p_remove,
 582         .driver  = {
 583                 .name  = "qcom_smp2p",
 584                 .of_match_table = qcom_smp2p_of_match,
 585         },
 586 };
 587 module_platform_driver(qcom_smp2p_driver);
 588
 589 MODULE_DESCRIPTION("Qualcomm Shared Memory Point to Point driver");
 590 MODULE_LICENSE("GPL v2");