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 ret;
 173         int i;
 174         u8 tmp_name[SMP2P_MAX_ENTRY_NAME];
 175
 176         in = smp2p->in;
 177
 178         /* Acquire smem item, if not already found */
 179         if (!in) {
 180                 ret = qcom_smem_get(pid, smem_id, (void **)&in, &size);
 181                 if (ret < 0) {
 182                         dev_err(smp2p->dev,
 183                                         "Unable to acquire remote smp2p item\n");
 184                         return IRQ_HANDLED;
 185                 }
 186
 187                 smp2p->in = in;
 188         }
 189
 190         /* Match newly created entries */
 191         for (i = smp2p->valid_entries; i < in->valid_entries; i++) {
 192                 list_for_each_entry(entry, &smp2p->inbound, node) {
 193                         memcpy_fromio(tmp_name, in->entries[i].name,
 194                                         SMP2P_MAX_ENTRY_NAME);
 195                         if (!strcmp(tmp_name, entry->name)) {
 196                                 entry->value = &in->entries[i].value;
 197                                 break;
 198                         }
 199                 }
 200         }
 201         smp2p->valid_entries = i;
 202
 203         /* Fire interrupts based on any value changes */
 204         list_for_each_entry(entry, &smp2p->inbound, node) {
 205                 /* Ignore entries not yet allocated by the remote side */
 206                 if (!entry->value)
 207                         continue;
 208
 209                 val = *entry->value;
 210
 211                 status = val ^ entry->last_value;
 212                 entry->last_value = val;
 213
 214                 /* No changes of this entry? */
 215                 if (!status)
 216                         continue;
 217
 218                 for_each_set_bit(i, entry->irq_enabled, 32) {
 219                         if (!(status & BIT(i)))
 220                                 continue;
 221
 222                         if (val & BIT(i)) {
 223                                 if (test_bit(i, entry->irq_rising)) {
 224                                         irq_pin = irq_find_mapping(entry->domain, i);
 225                                         handle_nested_irq(irq_pin);
 226                                 }
 227                         } else {
 228                                 if (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         }
 236
 237         return IRQ_HANDLED;
 238 }
 239
 240 static void smp2p_mask_irq(struct irq_data *irqd)
 241 {
 242         struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
 243         irq_hw_number_t irq = irqd_to_hwirq(irqd);
 244
 245         clear_bit(irq, entry->irq_enabled);
 246 }
 247
 248 static void smp2p_unmask_irq(struct irq_data *irqd)
 249 {
 250         struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
 251         irq_hw_number_t irq = irqd_to_hwirq(irqd);
 252
 253         set_bit(irq, entry->irq_enabled);
 254 }
 255
 256 static int smp2p_set_irq_type(struct irq_data *irqd, unsigned int type)
 257 {
 258         struct smp2p_entry *entry = irq_data_get_irq_chip_data(irqd);
 259         irq_hw_number_t irq = irqd_to_hwirq(irqd);
 260
 261         if (!(type & IRQ_TYPE_EDGE_BOTH))
 262                 return -EINVAL;
 263
 264         if (type & IRQ_TYPE_EDGE_RISING)
 265                 set_bit(irq, entry->irq_rising);
 266         else
 267                 clear_bit(irq, entry->irq_rising);
 268
 269         if (type & IRQ_TYPE_EDGE_FALLING)
 270                 set_bit(irq, entry->irq_falling);
 271         else
 272                 clear_bit(irq, entry->irq_falling);
 273
 274         return 0;
 275 }
 276
 277 static struct irq_chip smp2p_irq_chip = {
 278         .name           = "smp2p",
 279         .irq_mask       = smp2p_mask_irq,
 280         .irq_unmask     = smp2p_unmask_irq,
 281         .irq_set_type   = smp2p_set_irq_type,
 282 };
 283
 284 static int smp2p_irq_map(struct irq_domain *d,
 285                          unsigned int irq,
 286                          irq_hw_number_t hw)
 287 {
 288         struct smp2p_entry *entry = d->host_data;
 289
 290         irq_set_chip_and_handler(irq, &smp2p_irq_chip, handle_level_irq);
 291         irq_set_chip_data(irq, entry);
 292         irq_set_nested_thread(irq, 1);
 293
 294         irq_set_noprobe(irq);
 295
 296         return 0;
 297 }
 298
 299 static const struct irq_domain_ops smp2p_irq_ops = {
 300         .map = smp2p_irq_map,
 301         .xlate = irq_domain_xlate_twocell,
 302 };
 303
 304 static int smp2p_gpio_direction_output(struct gpio_chip *chip,
 305                                        unsigned offset,
 306                                        int value)
 307 {
 308         struct smp2p_entry *entry = container_of(chip, struct smp2p_entry, chip);
 309
 310         if (value)
 311                 *entry->value |= BIT(offset);
 312         else
 313                 *entry->value &= ~BIT(offset);
 314
 315         qcom_smp2p_kick(entry->smp2p);
 316
 317         return 0;
 318 }
 319
 320 static void smp2p_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 321 {
 322         smp2p_gpio_direction_output(chip, offset, value);
 323 }
 324
 325 static int qcom_smp2p_inbound_entry(struct qcom_smp2p *smp2p,
 326                                     struct smp2p_entry *entry,
 327                                     struct device_node *node)
 328 {
 329         entry->domain = irq_domain_add_linear(node, 32, &smp2p_irq_ops, entry);
 330         if (!entry->domain) {
 331                 dev_err(smp2p->dev, "failed to add irq_domain\n");
 332                 return -ENOMEM;
 333         }
 334
 335         return 0;
 336 }
 337
 338 static int qcom_smp2p_outbound_entry(struct qcom_smp2p *smp2p,
 339                                      struct smp2p_entry *entry,
 340                                      struct device_node *node)
 341 {
 342         struct smp2p_smem_item *out = smp2p->out;
 343         struct gpio_chip *chip;
 344         int ret;
 345
 346         /* Allocate an entry from the smem item */
 347         memcpy_toio(out->entries[out->valid_entries].name, entry->name, SMP2P_MAX_ENTRY_NAME);
 348         out->valid_entries++;
 349
 350         /* Make the logical entry reference the physical value */
 351         entry->value = &out->entries[out->valid_entries].value;
 352
 353         chip = &entry->chip;
 354         chip->base = -1;
 355         chip->ngpio = 32;
 356         chip->label = entry->name;
 357         chip->dev = smp2p->dev;
 358         chip->owner = THIS_MODULE;
 359         chip->of_node = node;
 360
 361         chip->set = smp2p_gpio_set;
 362         chip->direction_output = smp2p_gpio_direction_output;
 363
 364         ret = gpiochip_add(chip);
 365         if (ret)
 366                 dev_err(smp2p->dev, "failed register gpiochip\n");
 367
 368         return 0;
 369 }
 370
 371 static int qcom_smp2p_alloc_outbound_item(struct qcom_smp2p *smp2p)
 372 {
 373         struct smp2p_smem_item *out;
 374         unsigned smem_id = smp2p->smem_items[SMP2P_OUTBOUND];
 375         unsigned pid = smp2p->remote_pid;
 376         int ret;
 377
 378         ret = qcom_smem_alloc(pid, smem_id, sizeof(*out));
 379         if (ret < 0 && ret != -EEXIST) {
 380                 if (ret != -EPROBE_DEFER)
 381                         dev_err(smp2p->dev,
 382                                 "unable to allocate local smp2p item\n");
 383                 return ret;
 384         }
 385
 386         ret = qcom_smem_get(pid, smem_id, (void **)&out, NULL);
 387         if (ret < 0) {
 388                 dev_err(smp2p->dev, "Unable to acquire local smp2p item\n");
 389                 return ret;
 390         }
 391
 392         memset_io(out, 0, sizeof(*out));
 393         out->magic = SMP2P_MAGIC;
 394         out->local_pid = smp2p->local_pid;
 395         out->remote_pid = smp2p->remote_pid;
 396         out->total_entries = SMP2P_MAX_ENTRY;
 397         out->valid_entries = 0;
 398
 399         /*
 400          * Make sure the rest of the header is written before we validate the
 401          * item by writing a valid version number.
 402          */
 403         wmb();
 404         out->version = 1;
 405
 406         qcom_smp2p_kick(smp2p);
 407
 408         smp2p->out = out;
 409
 410         return 0;
 411 }
 412
 413 static int smp2p_parse_ipc(struct qcom_smp2p *smp2p)
 414 {
 415         struct device_node *syscon;
 416         struct device *dev = smp2p->dev;
 417         const char *key;
 418         int ret;
 419
 420         syscon = of_parse_phandle(dev->of_node, "qcom,ipc", 0);
 421         if (!syscon) {
 422                 dev_err(dev, "no qcom,ipc node\n");
 423                 return -ENODEV;
 424         }
 425
 426         smp2p->ipc_regmap = syscon_node_to_regmap(syscon);
 427         if (IS_ERR(smp2p->ipc_regmap))
 428                 return PTR_ERR(smp2p->ipc_regmap);
 429
 430         key = "qcom,ipc";
 431         ret = of_property_read_u32_index(dev->of_node, key, 1, &smp2p->ipc_offset);
 432         if (ret < 0) {
 433                 dev_err(dev, "no offset in %s\n", key);
 434                 return -EINVAL;
 435         }
 436
 437         ret = of_property_read_u32_index(dev->of_node, key, 2, &smp2p->ipc_bit);
 438         if (ret < 0) {
 439                 dev_err(dev, "no bit in %s\n", key);
 440                 return -EINVAL;
 441         }
 442
 443         return 0;
 444 }
 445
 446 static int qcom_smp2p_probe(struct platform_device *pdev)
 447 {
 448         struct smp2p_entry *entry;
 449         struct device_node *node;
 450         struct qcom_smp2p *smp2p;
 451         const char *key;
 452         int irq;
 453         int ret;
 454
 455         smp2p = devm_kzalloc(&pdev->dev, sizeof(*smp2p), GFP_KERNEL);
 456         if (!smp2p)
 457                 return -ENOMEM;
 458
 459         smp2p->dev = &pdev->dev;
 460         INIT_LIST_HEAD(&smp2p->inbound);
 461         INIT_LIST_HEAD(&smp2p->outbound);
 462
 463         platform_set_drvdata(pdev, smp2p);
 464
 465         ret = smp2p_parse_ipc(smp2p);
 466         if (ret)
 467                 return ret;
 468
 469         key = "qcom,smem";
 470         ret = of_property_read_u32_array(pdev->dev.of_node, key,
 471                                          smp2p->smem_items, 2);
 472         if (ret)
 473                 return ret;
 474
 475         key = "qcom,local-pid";
 476         ret = of_property_read_u32(pdev->dev.of_node, key, &smp2p->local_pid);
 477         if (ret < 0) {
 478                 dev_err(&pdev->dev, "failed to read %s\n", key);
 479                 return -EINVAL;
 480         }
 481
 482         key = "qcom,remote-pid";
 483         ret = of_property_read_u32(pdev->dev.of_node, key, &smp2p->remote_pid);
 484         if (ret < 0) {
 485                 dev_err(&pdev->dev, "failed to read %s\n", key);
 486                 return -EINVAL;
 487         }
 488
 489         irq = platform_get_irq(pdev, 0);
 490         if (irq < 0) {
 491                 dev_err(&pdev->dev, "unable to acquire smp2p interrupt\n");
 492                 return irq;
 493         }
 494
 495         ret = qcom_smp2p_alloc_outbound_item(smp2p);
 496         if (ret < 0)
 497                 return ret;
 498
 499         for_each_available_child_of_node(pdev->dev.of_node, node) {
 500                 entry = devm_kzalloc(&pdev->dev, sizeof(*entry), GFP_KERNEL);
 501                 if (!entry) {
 502                         ret = -ENOMEM;
 503                         goto unwind_interfaces;
 504                 }
 505
 506                 entry->smp2p = smp2p;
 507
 508                 ret = of_property_read_string(node, "qcom,entry-name", &entry->name);
 509                 if (ret < 0)
 510                         goto unwind_interfaces;
 511
 512                 if (of_property_read_bool(node, "qcom,inbound")) {
 513                         ret = qcom_smp2p_inbound_entry(smp2p, entry, node);
 514                         if (ret < 0)
 515                                 goto unwind_interfaces;
 516
 517                         list_add(&entry->node, &smp2p->inbound);
 518                 } else if (of_property_read_bool(node, "qcom,outbound")) {
 519                         ret = qcom_smp2p_outbound_entry(smp2p, entry, node);
 520                         if (ret < 0)
 521                                 goto unwind_interfaces;
 522
 523                         list_add(&entry->node, &smp2p->outbound);
 524                 } else {
 525                         dev_err(&pdev->dev, "neither inbound nor outbound\n");
 526                         ret = -EINVAL;
 527                         goto unwind_interfaces;
 528                 }
 529         }
 530
 531         /* Kick the outgoing edge after allocating entries */
 532         qcom_smp2p_kick(smp2p);
 533
 534         ret = devm_request_threaded_irq(&pdev->dev, irq,
 535                                         NULL, qcom_smp2p_intr,
 536                                         IRQF_ONESHOT,
 537                                         "smp2p", (void *)smp2p);
 538         if (ret) {
 539                 dev_err(&pdev->dev, "failed to request interrupt\n");
 540                 goto unwind_interfaces;
 541         }
 542
 543
 544         return 0;
 545
 546 unwind_interfaces:
 547         list_for_each_entry(entry, &smp2p->inbound, node)
 548                 irq_domain_remove(entry->domain);
 549
 550         list_for_each_entry(entry, &smp2p->outbound, node)
 551                 gpiochip_remove(&entry->chip);
 552
 553         smp2p->out->valid_entries = 0;
 554
 555         return ret;
 556 }
 557
 558 static int qcom_smp2p_remove(struct platform_device *pdev)
 559 {
 560         struct qcom_smp2p *smp2p = platform_get_drvdata(pdev);
 561         struct smp2p_entry *entry;
 562
 563         list_for_each_entry(entry, &smp2p->inbound, node)
 564                 irq_domain_remove(entry->domain);
 565
 566         list_for_each_entry(entry, &smp2p->outbound, node)
 567                 gpiochip_remove(&entry->chip);
 568
 569         smp2p->out->valid_entries = 0;
 570
 571         return 0;
 572 }
 573
 574 static const struct of_device_id qcom_smp2p_of_match[] = {
 575         { .compatible = "qcom,smp2p" },
 576         {}
 577 };
 578 MODULE_DEVICE_TABLE(of, qcom_smp2p_of_match);
 579
 580 static struct platform_driver qcom_smp2p_driver = {
 581         .probe = qcom_smp2p_probe,
 582         .remove = qcom_smp2p_remove,
 583         .driver  = {
 584                 .name  = "qcom_smp2p",
 585                 .of_match_table = qcom_smp2p_of_match,
 586         },
 587 };
 588 module_platform_driver(qcom_smp2p_driver);
 589
 590 MODULE_DESCRIPTION("Qualcomm Shared Memory Point to Point driver");
 591 MODULE_LICENSE("GPL v2");