drivers/gpio/gpiolib-cdev.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/anon_inodes.h>
   4 #include <linux/atomic.h>
   5 #include <linux/bitmap.h>
   6 #include <linux/build_bug.h>
   7 #include <linux/cdev.h>
   8 #include <linux/compat.h>
   9 #include <linux/compiler.h>
  10 #include <linux/device.h>
  11 #include <linux/err.h>
  12 #include <linux/file.h>
  13 #include <linux/gpio.h>
  14 #include <linux/gpio/driver.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/irqreturn.h>
  17 #include <linux/kernel.h>
  18 #include <linux/kfifo.h>
  19 #include <linux/module.h>
  20 #include <linux/mutex.h>
  21 #include <linux/pinctrl/consumer.h>
  22 #include <linux/poll.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/timekeeping.h>
  25 #include <linux/uaccess.h>
  26 #include <linux/workqueue.h>
  27 #include <uapi/linux/gpio.h>
  28
  29 #include "gpiolib.h"
  30 #include "gpiolib-cdev.h"
  31
  32 /*
  33  * Array sizes must ensure 64-bit alignment and not create holes in the
  34  * struct packing.
  35  */
  36 static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2));
  37 static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8));
  38
  39 /*
  40  * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility
  41  */
  42 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8));
  43 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8));
  44 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8));
  45 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8));
  46 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8));
  47 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8));
  48 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8));
  49 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8));
  50
  51 /* Character device interface to GPIO.
  52  *
  53  * The GPIO character device, /dev/gpiochipN, provides userspace an
  54  * interface to gpiolib GPIOs via ioctl()s.
  55  */
  56
  57 /*
  58  * GPIO line handle management
  59  */
  60
  61 #ifdef CONFIG_GPIO_CDEV_V1
  62 /**
  63  * struct linehandle_state - contains the state of a userspace handle
  64  * @gdev: the GPIO device the handle pertains to
  65  * @label: consumer label used to tag descriptors
  66  * @descs: the GPIO descriptors held by this handle
  67  * @num_descs: the number of descriptors held in the descs array
  68  */
  69 struct linehandle_state {
  70         struct gpio_device *gdev;
  71         const char *label;
  72         struct gpio_desc *descs[GPIOHANDLES_MAX];
  73         u32 num_descs;
  74 };
  75
  76 #define GPIOHANDLE_REQUEST_VALID_FLAGS \
  77         (GPIOHANDLE_REQUEST_INPUT | \
  78         GPIOHANDLE_REQUEST_OUTPUT | \
  79         GPIOHANDLE_REQUEST_ACTIVE_LOW | \
  80         GPIOHANDLE_REQUEST_BIAS_PULL_UP | \
  81         GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \
  82         GPIOHANDLE_REQUEST_BIAS_DISABLE | \
  83         GPIOHANDLE_REQUEST_OPEN_DRAIN | \
  84         GPIOHANDLE_REQUEST_OPEN_SOURCE)
  85
  86 static int linehandle_validate_flags(u32 flags)
  87 {
  88         /* Return an error if an unknown flag is set */
  89         if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
  90                 return -EINVAL;
  91
  92         /*
  93          * Do not allow both INPUT & OUTPUT flags to be set as they are
  94          * contradictory.
  95          */
  96         if ((flags & GPIOHANDLE_REQUEST_INPUT) &&
  97             (flags & GPIOHANDLE_REQUEST_OUTPUT))
  98                 return -EINVAL;
  99
 100         /*
 101          * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
 102          * the hardware actually supports enabling both at the same time the
 103          * electrical result would be disastrous.
 104          */
 105         if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
 106             (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
 107                 return -EINVAL;
 108
 109         /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
 110         if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) &&
 111             ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
 112              (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
 113                 return -EINVAL;
 114
 115         /* Bias flags only allowed for input or output mode. */
 116         if (!((flags & GPIOHANDLE_REQUEST_INPUT) ||
 117               (flags & GPIOHANDLE_REQUEST_OUTPUT)) &&
 118             ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) ||
 119              (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) ||
 120              (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
 121                 return -EINVAL;
 122
 123         /* Only one bias flag can be set. */
 124         if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
 125              (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
 126                        GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
 127             ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
 128              (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
 129                 return -EINVAL;
 130
 131         return 0;
 132 }
 133
 134 static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp)
 135 {
 136         assign_bit(FLAG_ACTIVE_LOW, flagsp,
 137                    lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
 138         assign_bit(FLAG_OPEN_DRAIN, flagsp,
 139                    lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
 140         assign_bit(FLAG_OPEN_SOURCE, flagsp,
 141                    lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
 142         assign_bit(FLAG_PULL_UP, flagsp,
 143                    lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
 144         assign_bit(FLAG_PULL_DOWN, flagsp,
 145                    lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
 146         assign_bit(FLAG_BIAS_DISABLE, flagsp,
 147                    lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
 148 }
 149
 150 static long linehandle_set_config(struct linehandle_state *lh,
 151                                   void __user *ip)
 152 {
 153         struct gpiohandle_config gcnf;
 154         struct gpio_desc *desc;
 155         int i, ret;
 156         u32 lflags;
 157
 158         if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
 159                 return -EFAULT;
 160
 161         lflags = gcnf.flags;
 162         ret = linehandle_validate_flags(lflags);
 163         if (ret)
 164                 return ret;
 165
 166         for (i = 0; i < lh->num_descs; i++) {
 167                 desc = lh->descs[i];
 168                 linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags);
 169
 170                 /*
 171                  * Lines have to be requested explicitly for input
 172                  * or output, else the line will be treated "as is".
 173                  */
 174                 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
 175                         int val = !!gcnf.default_values[i];
 176
 177                         ret = gpiod_direction_output(desc, val);
 178                         if (ret)
 179                                 return ret;
 180                 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
 181                         ret = gpiod_direction_input(desc);
 182                         if (ret)
 183                                 return ret;
 184                 }
 185
 186                 blocking_notifier_call_chain(&desc->gdev->notifier,
 187                                              GPIO_V2_LINE_CHANGED_CONFIG,
 188                                              desc);
 189         }
 190         return 0;
 191 }
 192
 193 static long linehandle_ioctl(struct file *file, unsigned int cmd,
 194                              unsigned long arg)
 195 {
 196         struct linehandle_state *lh = file->private_data;
 197         void __user *ip = (void __user *)arg;
 198         struct gpiohandle_data ghd;
 199         DECLARE_BITMAP(vals, GPIOHANDLES_MAX);
 200         int i;
 201
 202         if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
 203                 /* NOTE: It's ok to read values of output lines. */
 204                 int ret = gpiod_get_array_value_complex(false,
 205                                                         true,
 206                                                         lh->num_descs,
 207                                                         lh->descs,
 208                                                         NULL,
 209                                                         vals);
 210                 if (ret)
 211                         return ret;
 212
 213                 memset(&ghd, 0, sizeof(ghd));
 214                 for (i = 0; i < lh->num_descs; i++)
 215                         ghd.values[i] = test_bit(i, vals);
 216
 217                 if (copy_to_user(ip, &ghd, sizeof(ghd)))
 218                         return -EFAULT;
 219
 220                 return 0;
 221         } else if (cmd == GPIOHANDLE_SET_LINE_VALUES_IOCTL) {
 222                 /*
 223                  * All line descriptors were created at once with the same
 224                  * flags so just check if the first one is really output.
 225                  */
 226                 if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags))
 227                         return -EPERM;
 228
 229                 if (copy_from_user(&ghd, ip, sizeof(ghd)))
 230                         return -EFAULT;
 231
 232                 /* Clamp all values to [0,1] */
 233                 for (i = 0; i < lh->num_descs; i++)
 234                         __assign_bit(i, vals, ghd.values[i]);
 235
 236                 /* Reuse the array setting function */
 237                 return gpiod_set_array_value_complex(false,
 238                                                      true,
 239                                                      lh->num_descs,
 240                                                      lh->descs,
 241                                                      NULL,
 242                                                      vals);
 243         } else if (cmd == GPIOHANDLE_SET_CONFIG_IOCTL) {
 244                 return linehandle_set_config(lh, ip);
 245         }
 246         return -EINVAL;
 247 }
 248
 249 #ifdef CONFIG_COMPAT
 250 static long linehandle_ioctl_compat(struct file *file, unsigned int cmd,
 251                                     unsigned long arg)
 252 {
 253         return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
 254 }
 255 #endif
 256
 257 static void linehandle_free(struct linehandle_state *lh)
 258 {
 259         int i;
 260
 261         for (i = 0; i < lh->num_descs; i++)
 262                 if (lh->descs[i])
 263                         gpiod_free(lh->descs[i]);
 264         kfree(lh->label);
 265         put_device(&lh->gdev->dev);
 266         kfree(lh);
 267 }
 268
 269 static int linehandle_release(struct inode *inode, struct file *file)
 270 {
 271         linehandle_free(file->private_data);
 272         return 0;
 273 }
 274
 275 static const struct file_operations linehandle_fileops = {
 276         .release = linehandle_release,
 277         .owner = THIS_MODULE,
 278         .llseek = noop_llseek,
 279         .unlocked_ioctl = linehandle_ioctl,
 280 #ifdef CONFIG_COMPAT
 281         .compat_ioctl = linehandle_ioctl_compat,
 282 #endif
 283 };
 284
 285 static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 286 {
 287         struct gpiohandle_request handlereq;
 288         struct linehandle_state *lh;
 289         struct file *file;
 290         int fd, i, ret;
 291         u32 lflags;
 292
 293         if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
 294                 return -EFAULT;
 295         if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
 296                 return -EINVAL;
 297
 298         lflags = handlereq.flags;
 299
 300         ret = linehandle_validate_flags(lflags);
 301         if (ret)
 302                 return ret;
 303
 304         lh = kzalloc(sizeof(*lh), GFP_KERNEL);
 305         if (!lh)
 306                 return -ENOMEM;
 307         lh->gdev = gdev;
 308         get_device(&gdev->dev);
 309
 310         if (handlereq.consumer_label[0] != '\0') {
 311                 /* label is only initialized if consumer_label is set */
 312                 lh->label = kstrndup(handlereq.consumer_label,
 313                                      sizeof(handlereq.consumer_label) - 1,
 314                                      GFP_KERNEL);
 315                 if (!lh->label) {
 316                         ret = -ENOMEM;
 317                         goto out_free_lh;
 318                 }
 319         }
 320
 321         lh->num_descs = handlereq.lines;
 322
 323         /* Request each GPIO */
 324         for (i = 0; i < handlereq.lines; i++) {
 325                 u32 offset = handlereq.lineoffsets[i];
 326                 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
 327
 328                 if (IS_ERR(desc)) {
 329                         ret = PTR_ERR(desc);
 330                         goto out_free_lh;
 331                 }
 332
 333                 ret = gpiod_request(desc, lh->label);
 334                 if (ret)
 335                         goto out_free_lh;
 336                 lh->descs[i] = desc;
 337                 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);
 338
 339                 ret = gpiod_set_transitory(desc, false);
 340                 if (ret < 0)
 341                         goto out_free_lh;
 342
 343                 /*
 344                  * Lines have to be requested explicitly for input
 345                  * or output, else the line will be treated "as is".
 346                  */
 347                 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
 348                         int val = !!handlereq.default_values[i];
 349
 350                         ret = gpiod_direction_output(desc, val);
 351                         if (ret)
 352                                 goto out_free_lh;
 353                 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
 354                         ret = gpiod_direction_input(desc);
 355                         if (ret)
 356                                 goto out_free_lh;
 357                 }
 358
 359                 blocking_notifier_call_chain(&desc->gdev->notifier,
 360                                              GPIO_V2_LINE_CHANGED_REQUESTED, desc);
 361
 362                 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
 363                         offset);
 364         }
 365
 366         fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
 367         if (fd < 0) {
 368                 ret = fd;
 369                 goto out_free_lh;
 370         }
 371
 372         file = anon_inode_getfile("gpio-linehandle",
 373                                   &linehandle_fileops,
 374                                   lh,
 375                                   O_RDONLY | O_CLOEXEC);
 376         if (IS_ERR(file)) {
 377                 ret = PTR_ERR(file);
 378                 goto out_put_unused_fd;
 379         }
 380
 381         handlereq.fd = fd;
 382         if (copy_to_user(ip, &handlereq, sizeof(handlereq))) {
 383                 /*
 384                  * fput() will trigger the release() callback, so do not go onto
 385                  * the regular error cleanup path here.
 386                  */
 387                 fput(file);
 388                 put_unused_fd(fd);
 389                 return -EFAULT;
 390         }
 391
 392         fd_install(fd, file);
 393
 394         dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
 395                 lh->num_descs);
 396
 397         return 0;
 398
 399 out_put_unused_fd:
 400         put_unused_fd(fd);
 401 out_free_lh:
 402         linehandle_free(lh);
 403         return ret;
 404 }
 405 #endif /* CONFIG_GPIO_CDEV_V1 */
 406
 407 /**
 408  * struct line - contains the state of a requested line
 409  * @desc: the GPIO descriptor for this line.
 410  * @req: the corresponding line request
 411  * @irq: the interrupt triggered in response to events on this GPIO
 412  * @eflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or
 413  * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied
 414  * @timestamp_ns: cache for the timestamp storing it between hardirq and
 415  * IRQ thread, used to bring the timestamp close to the actual event
 416  * @req_seqno: the seqno for the current edge event in the sequence of
 417  * events for the corresponding line request. This is drawn from the @req.
 418  * @line_seqno: the seqno for the current edge event in the sequence of
 419  * events for this line.
 420  * @work: the worker that implements software debouncing
 421  * @sw_debounced: flag indicating if the software debouncer is active
 422  * @level: the current debounced physical level of the line
 423  */
 424 struct line {
 425         struct gpio_desc *desc;
 426         /*
 427          * -- edge detector specific fields --
 428          */
 429         struct linereq *req;
 430         unsigned int irq;
 431         u64 eflags;
 432         /*
 433          * timestamp_ns and req_seqno are accessed only by
 434          * edge_irq_handler() and edge_irq_thread(), which are themselves
 435          * mutually exclusive, so no additional protection is necessary.
 436          */
 437         u64 timestamp_ns;
 438         u32 req_seqno;
 439         /*
 440          * line_seqno is accessed by either edge_irq_thread() or
 441          * debounce_work_func(), which are themselves mutually exclusive,
 442          * so no additional protection is necessary.
 443          */
 444         u32 line_seqno;
 445         /*
 446          * -- debouncer specific fields --
 447          */
 448         struct delayed_work work;
 449         /*
 450          * sw_debounce is accessed by linereq_set_config(), which is the
 451          * only setter, and linereq_get_values(), which can live with a
 452          * slightly stale value.
 453          */
 454         unsigned int sw_debounced;
 455         /*
 456          * level is accessed by debounce_work_func(), which is the only
 457          * setter, and linereq_get_values() which can live with a slightly
 458          * stale value.
 459          */
 460         unsigned int level;
 461 };
 462
 463 /**
 464  * struct linereq - contains the state of a userspace line request
 465  * @gdev: the GPIO device the line request pertains to
 466  * @label: consumer label used to tag GPIO descriptors
 467  * @num_lines: the number of lines in the lines array
 468  * @wait: wait queue that handles blocking reads of events
 469  * @event_buffer_size: the number of elements allocated in @events
 470  * @events: KFIFO for the GPIO events
 471  * @seqno: the sequence number for edge events generated on all lines in
 472  * this line request.  Note that this is not used when @num_lines is 1, as
 473  * the line_seqno is then the same and is cheaper to calculate.
 474  * @config_mutex: mutex for serializing ioctl() calls to ensure consistency
 475  * of configuration, particularly multi-step accesses to desc flags.
 476  * @lines: the lines held by this line request, with @num_lines elements.
 477  */
 478 struct linereq {
 479         struct gpio_device *gdev;
 480         const char *label;
 481         u32 num_lines;
 482         wait_queue_head_t wait;
 483         u32 event_buffer_size;
 484         DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
 485         atomic_t seqno;
 486         struct mutex config_mutex;
 487         struct line lines[];
 488 };
 489
 490 #define GPIO_V2_LINE_BIAS_FLAGS \
 491         (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \
 492          GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \
 493          GPIO_V2_LINE_FLAG_BIAS_DISABLED)
 494
 495 #define GPIO_V2_LINE_DIRECTION_FLAGS \
 496         (GPIO_V2_LINE_FLAG_INPUT | \
 497          GPIO_V2_LINE_FLAG_OUTPUT)
 498
 499 #define GPIO_V2_LINE_DRIVE_FLAGS \
 500         (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \
 501          GPIO_V2_LINE_FLAG_OPEN_SOURCE)
 502
 503 #define GPIO_V2_LINE_EDGE_FLAGS \
 504         (GPIO_V2_LINE_FLAG_EDGE_RISING | \
 505          GPIO_V2_LINE_FLAG_EDGE_FALLING)
 506
 507 #define GPIO_V2_LINE_VALID_FLAGS \
 508         (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
 509          GPIO_V2_LINE_DIRECTION_FLAGS | \
 510          GPIO_V2_LINE_DRIVE_FLAGS | \
 511          GPIO_V2_LINE_EDGE_FLAGS | \
 512          GPIO_V2_LINE_BIAS_FLAGS)
 513
 514 static void linereq_put_event(struct linereq *lr,
 515                               struct gpio_v2_line_event *le)
 516 {
 517         bool overflow = false;
 518
 519         spin_lock(&lr->wait.lock);
 520         if (kfifo_is_full(&lr->events)) {
 521                 overflow = true;
 522                 kfifo_skip(&lr->events);
 523         }
 524         kfifo_in(&lr->events, le, 1);
 525         spin_unlock(&lr->wait.lock);
 526         if (!overflow)
 527                 wake_up_poll(&lr->wait, EPOLLIN);
 528         else
 529                 pr_debug_ratelimited("event FIFO is full - event dropped\n");
 530 }
 531
 532 static irqreturn_t edge_irq_thread(int irq, void *p)
 533 {
 534         struct line *line = p;
 535         struct linereq *lr = line->req;
 536         struct gpio_v2_line_event le;
 537
 538         /* Do not leak kernel stack to userspace */
 539         memset(&le, 0, sizeof(le));
 540
 541         if (line->timestamp_ns) {
 542                 le.timestamp_ns = line->timestamp_ns;
 543         } else {
 544                 /*
 545                  * We may be running from a nested threaded interrupt in
 546                  * which case we didn't get the timestamp from
 547                  * edge_irq_handler().
 548                  */
 549                 le.timestamp_ns = ktime_get_ns();
 550                 if (lr->num_lines != 1)
 551                         line->req_seqno = atomic_inc_return(&lr->seqno);
 552         }
 553         line->timestamp_ns = 0;
 554
 555         if (line->eflags == (GPIO_V2_LINE_FLAG_EDGE_RISING |
 556                              GPIO_V2_LINE_FLAG_EDGE_FALLING)) {
 557                 int level = gpiod_get_value_cansleep(line->desc);
 558
 559                 if (level)
 560                         /* Emit low-to-high event */
 561                         le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
 562                 else
 563                         /* Emit high-to-low event */
 564                         le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
 565         } else if (line->eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) {
 566                 /* Emit low-to-high event */
 567                 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
 568         } else if (line->eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) {
 569                 /* Emit high-to-low event */
 570                 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
 571         } else {
 572                 return IRQ_NONE;
 573         }
 574         line->line_seqno++;
 575         le.line_seqno = line->line_seqno;
 576         le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
 577         le.offset = gpio_chip_hwgpio(line->desc);
 578
 579         linereq_put_event(lr, &le);
 580
 581         return IRQ_HANDLED;
 582 }
 583
 584 static irqreturn_t edge_irq_handler(int irq, void *p)
 585 {
 586         struct line *line = p;
 587         struct linereq *lr = line->req;
 588
 589         /*
 590          * Just store the timestamp in hardirq context so we get it as
 591          * close in time as possible to the actual event.
 592          */
 593         line->timestamp_ns = ktime_get_ns();
 594
 595         if (lr->num_lines != 1)
 596                 line->req_seqno = atomic_inc_return(&lr->seqno);
 597
 598         return IRQ_WAKE_THREAD;
 599 }
 600
 601 /*
 602  * returns the current debounced logical value.
 603  */
 604 static bool debounced_value(struct line *line)
 605 {
 606         bool value;
 607
 608         /*
 609          * minor race - debouncer may be stopped here, so edge_detector_stop()
 610          * must leave the value unchanged so the following will read the level
 611          * from when the debouncer was last running.
 612          */
 613         value = READ_ONCE(line->level);
 614
 615         if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
 616                 value = !value;
 617
 618         return value;
 619 }
 620
 621 static irqreturn_t debounce_irq_handler(int irq, void *p)
 622 {
 623         struct line *line = p;
 624
 625         mod_delayed_work(system_wq, &line->work,
 626                 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
 627
 628         return IRQ_HANDLED;
 629 }
 630
 631 static void debounce_work_func(struct work_struct *work)
 632 {
 633         struct gpio_v2_line_event le;
 634         struct line *line = container_of(work, struct line, work.work);
 635         struct linereq *lr;
 636         int level;
 637
 638         level = gpiod_get_raw_value_cansleep(line->desc);
 639         if (level < 0) {
 640                 pr_debug_ratelimited("debouncer failed to read line value\n");
 641                 return;
 642         }
 643
 644         if (READ_ONCE(line->level) == level)
 645                 return;
 646
 647         WRITE_ONCE(line->level, level);
 648
 649         /* -- edge detection -- */
 650         if (!line->eflags)
 651                 return;
 652
 653         /* switch from physical level to logical - if they differ */
 654         if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
 655                 level = !level;
 656
 657         /* ignore edges that are not being monitored */
 658         if (((line->eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) ||
 659             ((line->eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level))
 660                 return;
 661
 662         /* Do not leak kernel stack to userspace */
 663         memset(&le, 0, sizeof(le));
 664
 665         lr = line->req;
 666         le.timestamp_ns = ktime_get_ns();
 667         le.offset = gpio_chip_hwgpio(line->desc);
 668         line->line_seqno++;
 669         le.line_seqno = line->line_seqno;
 670         le.seqno = (lr->num_lines == 1) ?
 671                 le.line_seqno : atomic_inc_return(&lr->seqno);
 672
 673         if (level)
 674                 /* Emit low-to-high event */
 675                 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
 676         else
 677                 /* Emit high-to-low event */
 678                 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
 679
 680         linereq_put_event(lr, &le);
 681 }
 682
 683 static int debounce_setup(struct line *line,
 684                           unsigned int debounce_period_us)
 685 {
 686         unsigned long irqflags;
 687         int ret, level, irq;
 688
 689         /* try hardware */
 690         ret = gpiod_set_debounce(line->desc, debounce_period_us);
 691         if (!ret) {
 692                 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
 693                 return ret;
 694         }
 695         if (ret != -ENOTSUPP)
 696                 return ret;
 697
 698         if (debounce_period_us) {
 699                 /* setup software debounce */
 700                 level = gpiod_get_raw_value_cansleep(line->desc);
 701                 if (level < 0)
 702                         return level;
 703
 704                 irq = gpiod_to_irq(line->desc);
 705                 if (irq < 0)
 706                         return -ENXIO;
 707
 708                 WRITE_ONCE(line->level, level);
 709                 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
 710                 ret = request_irq(irq, debounce_irq_handler, irqflags,
 711                                   line->req->label, line);
 712                 if (ret)
 713                         return ret;
 714
 715                 WRITE_ONCE(line->sw_debounced, 1);
 716                 line->irq = irq;
 717         }
 718         return 0;
 719 }
 720
 721 static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc,
 722                                           unsigned int line_idx)
 723 {
 724         unsigned int i;
 725         u64 mask = BIT_ULL(line_idx);
 726
 727         for (i = 0; i < lc->num_attrs; i++) {
 728                 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
 729                     (lc->attrs[i].mask & mask))
 730                         return true;
 731         }
 732         return false;
 733 }
 734
 735 static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
 736                                                unsigned int line_idx)
 737 {
 738         unsigned int i;
 739         u64 mask = BIT_ULL(line_idx);
 740
 741         for (i = 0; i < lc->num_attrs; i++) {
 742                 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
 743                     (lc->attrs[i].mask & mask))
 744                         return lc->attrs[i].attr.debounce_period_us;
 745         }
 746         return 0;
 747 }
 748
 749 static void edge_detector_stop(struct line *line)
 750 {
 751         if (line->irq) {
 752                 free_irq(line->irq, line);
 753                 line->irq = 0;
 754         }
 755
 756         cancel_delayed_work_sync(&line->work);
 757         WRITE_ONCE(line->sw_debounced, 0);
 758         line->eflags = 0;
 759         /* do not change line->level - see comment in debounced_value() */
 760 }
 761
 762 static int edge_detector_setup(struct line *line,
 763                                struct gpio_v2_line_config *lc,
 764                                unsigned int line_idx,
 765                                u64 eflags)
 766 {
 767         u32 debounce_period_us;
 768         unsigned long irqflags = 0;
 769         int irq, ret;
 770
 771         if (eflags && !kfifo_initialized(&line->req->events)) {
 772                 ret = kfifo_alloc(&line->req->events,
 773                                   line->req->event_buffer_size, GFP_KERNEL);
 774                 if (ret)
 775                         return ret;
 776         }
 777         line->eflags = eflags;
 778         if (gpio_v2_line_config_debounced(lc, line_idx)) {
 779                 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
 780                 ret = debounce_setup(line, debounce_period_us);
 781                 if (ret)
 782                         return ret;
 783                 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
 784         }
 785
 786         /* detection disabled or sw debouncer will provide edge detection */
 787         if (!eflags || READ_ONCE(line->sw_debounced))
 788                 return 0;
 789
 790         irq = gpiod_to_irq(line->desc);
 791         if (irq < 0)
 792                 return -ENXIO;
 793
 794         if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
 795                 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
 796                         IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
 797         if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
 798                 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
 799                         IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
 800         irqflags |= IRQF_ONESHOT;
 801
 802         /* Request a thread to read the events */
 803         ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
 804                                    irqflags, line->req->label, line);
 805         if (ret)
 806                 return ret;
 807
 808         line->irq = irq;
 809         return 0;
 810 }
 811
 812 static int edge_detector_update(struct line *line,
 813                                 struct gpio_v2_line_config *lc,
 814                                 unsigned int line_idx,
 815                                 u64 eflags, bool polarity_change)
 816 {
 817         unsigned int debounce_period_us =
 818                 gpio_v2_line_config_debounce_period(lc, line_idx);
 819
 820         if ((line->eflags == eflags) && !polarity_change &&
 821             (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us))
 822                 return 0;
 823
 824         /* sw debounced and still will be...*/
 825         if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
 826                 line->eflags = eflags;
 827                 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
 828                 return 0;
 829         }
 830
 831         /* reconfiguring edge detection or sw debounce being disabled */
 832         if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
 833             (!debounce_period_us && READ_ONCE(line->sw_debounced)))
 834                 edge_detector_stop(line);
 835
 836         return edge_detector_setup(line, lc, line_idx, eflags);
 837 }
 838
 839 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
 840                                      unsigned int line_idx)
 841 {
 842         unsigned int i;
 843         u64 mask = BIT_ULL(line_idx);
 844
 845         for (i = 0; i < lc->num_attrs; i++) {
 846                 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) &&
 847                     (lc->attrs[i].mask & mask))
 848                         return lc->attrs[i].attr.flags;
 849         }
 850         return lc->flags;
 851 }
 852
 853 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc,
 854                                             unsigned int line_idx)
 855 {
 856         unsigned int i;
 857         u64 mask = BIT_ULL(line_idx);
 858
 859         for (i = 0; i < lc->num_attrs; i++) {
 860                 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) &&
 861                     (lc->attrs[i].mask & mask))
 862                         return !!(lc->attrs[i].attr.values & mask);
 863         }
 864         return 0;
 865 }
 866
 867 static int gpio_v2_line_flags_validate(u64 flags)
 868 {
 869         /* Return an error if an unknown flag is set */
 870         if (flags & ~GPIO_V2_LINE_VALID_FLAGS)
 871                 return -EINVAL;
 872
 873         /*
 874          * Do not allow both INPUT and OUTPUT flags to be set as they are
 875          * contradictory.
 876          */
 877         if ((flags & GPIO_V2_LINE_FLAG_INPUT) &&
 878             (flags & GPIO_V2_LINE_FLAG_OUTPUT))
 879                 return -EINVAL;
 880
 881         /* Edge detection requires explicit input. */
 882         if ((flags & GPIO_V2_LINE_EDGE_FLAGS) &&
 883             !(flags & GPIO_V2_LINE_FLAG_INPUT))
 884                 return -EINVAL;
 885
 886         /*
 887          * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single
 888          * request. If the hardware actually supports enabling both at the
 889          * same time the electrical result would be disastrous.
 890          */
 891         if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) &&
 892             (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE))
 893                 return -EINVAL;
 894
 895         /* Drive requires explicit output direction. */
 896         if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) &&
 897             !(flags & GPIO_V2_LINE_FLAG_OUTPUT))
 898                 return -EINVAL;
 899
 900         /* Bias requires explicit direction. */
 901         if ((flags & GPIO_V2_LINE_BIAS_FLAGS) &&
 902             !(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
 903                 return -EINVAL;
 904
 905         /* Only one bias flag can be set. */
 906         if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) &&
 907              (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN |
 908                        GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) ||
 909             ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) &&
 910              (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)))
 911                 return -EINVAL;
 912
 913         return 0;
 914 }
 915
 916 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
 917                                         unsigned int num_lines)
 918 {
 919         unsigned int i;
 920         u64 flags;
 921         int ret;
 922
 923         if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX)
 924                 return -EINVAL;
 925
 926         if (memchr_inv(lc->padding, 0, sizeof(lc->padding)))
 927                 return -EINVAL;
 928
 929         for (i = 0; i < num_lines; i++) {
 930                 flags = gpio_v2_line_config_flags(lc, i);
 931                 ret = gpio_v2_line_flags_validate(flags);
 932                 if (ret)
 933                         return ret;
 934
 935                 /* debounce requires explicit input */
 936                 if (gpio_v2_line_config_debounced(lc, i) &&
 937                     !(flags & GPIO_V2_LINE_FLAG_INPUT))
 938                         return -EINVAL;
 939         }
 940         return 0;
 941 }
 942
 943 static void gpio_v2_line_config_flags_to_desc_flags(u64 flags,
 944                                                     unsigned long *flagsp)
 945 {
 946         assign_bit(FLAG_ACTIVE_LOW, flagsp,
 947                    flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW);
 948
 949         if (flags & GPIO_V2_LINE_FLAG_OUTPUT)
 950                 set_bit(FLAG_IS_OUT, flagsp);
 951         else if (flags & GPIO_V2_LINE_FLAG_INPUT)
 952                 clear_bit(FLAG_IS_OUT, flagsp);
 953
 954         assign_bit(FLAG_EDGE_RISING, flagsp,
 955                    flags & GPIO_V2_LINE_FLAG_EDGE_RISING);
 956         assign_bit(FLAG_EDGE_FALLING, flagsp,
 957                    flags & GPIO_V2_LINE_FLAG_EDGE_FALLING);
 958
 959         assign_bit(FLAG_OPEN_DRAIN, flagsp,
 960                    flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN);
 961         assign_bit(FLAG_OPEN_SOURCE, flagsp,
 962                    flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE);
 963
 964         assign_bit(FLAG_PULL_UP, flagsp,
 965                    flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP);
 966         assign_bit(FLAG_PULL_DOWN, flagsp,
 967                    flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN);
 968         assign_bit(FLAG_BIAS_DISABLE, flagsp,
 969                    flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED);
 970 }
 971
 972 static long linereq_get_values(struct linereq *lr, void __user *ip)
 973 {
 974         struct gpio_v2_line_values lv;
 975         DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
 976         struct gpio_desc **descs;
 977         unsigned int i, didx, num_get;
 978         bool val;
 979         int ret;
 980
 981         /* NOTE: It's ok to read values of output lines. */
 982         if (copy_from_user(&lv, ip, sizeof(lv)))
 983                 return -EFAULT;
 984
 985         for (num_get = 0, i = 0; i < lr->num_lines; i++) {
 986                 if (lv.mask & BIT_ULL(i)) {
 987                         num_get++;
 988                         descs = &lr->lines[i].desc;
 989                 }
 990         }
 991
 992         if (num_get == 0)
 993                 return -EINVAL;
 994
 995         if (num_get != 1) {
 996                 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL);
 997                 if (!descs)
 998                         return -ENOMEM;
 999                 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1000                         if (lv.mask & BIT_ULL(i)) {
1001                                 descs[didx] = lr->lines[i].desc;
1002                                 didx++;
1003                         }
1004                 }
1005         }
1006         ret = gpiod_get_array_value_complex(false, true, num_get,
1007                                             descs, NULL, vals);
1008
1009         if (num_get != 1)
1010                 kfree(descs);
1011         if (ret)
1012                 return ret;
1013
1014         lv.bits = 0;
1015         for (didx = 0, i = 0; i < lr->num_lines; i++) {
1016                 if (lv.mask & BIT_ULL(i)) {
1017                         if (lr->lines[i].sw_debounced)
1018                                 val = debounced_value(&lr->lines[i]);
1019                         else
1020                                 val = test_bit(didx, vals);
1021                         if (val)
1022                                 lv.bits |= BIT_ULL(i);
1023                         didx++;
1024                 }
1025         }
1026
1027         if (copy_to_user(ip, &lv, sizeof(lv)))
1028                 return -EFAULT;
1029
1030         return 0;
1031 }
1032
1033 static long linereq_set_values_unlocked(struct linereq *lr,
1034                                         struct gpio_v2_line_values *lv)
1035 {
1036         DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1037         struct gpio_desc **descs;
1038         unsigned int i, didx, num_set;
1039         int ret;
1040
1041         bitmap_zero(vals, GPIO_V2_LINES_MAX);
1042         for (num_set = 0, i = 0; i < lr->num_lines; i++) {
1043                 if (lv->mask & BIT_ULL(i)) {
1044                         if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
1045                                 return -EPERM;
1046                         if (lv->bits & BIT_ULL(i))
1047                                 __set_bit(num_set, vals);
1048                         num_set++;
1049                         descs = &lr->lines[i].desc;
1050                 }
1051         }
1052         if (num_set == 0)
1053                 return -EINVAL;
1054
1055         if (num_set != 1) {
1056                 /* build compacted desc array and values */
1057                 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);
1058                 if (!descs)
1059                         return -ENOMEM;
1060                 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1061                         if (lv->mask & BIT_ULL(i)) {
1062                                 descs[didx] = lr->lines[i].desc;
1063                                 didx++;
1064                         }
1065                 }
1066         }
1067         ret = gpiod_set_array_value_complex(false, true, num_set,
1068                                             descs, NULL, vals);
1069
1070         if (num_set != 1)
1071                 kfree(descs);
1072         return ret;
1073 }
1074
1075 static long linereq_set_values(struct linereq *lr, void __user *ip)
1076 {
1077         struct gpio_v2_line_values lv;
1078         int ret;
1079
1080         if (copy_from_user(&lv, ip, sizeof(lv)))
1081                 return -EFAULT;
1082
1083         mutex_lock(&lr->config_mutex);
1084
1085         ret = linereq_set_values_unlocked(lr, &lv);
1086
1087         mutex_unlock(&lr->config_mutex);
1088
1089         return ret;
1090 }
1091
1092 static long linereq_set_config_unlocked(struct linereq *lr,
1093                                         struct gpio_v2_line_config *lc)
1094 {
1095         struct gpio_desc *desc;
1096         unsigned int i;
1097         u64 flags;
1098         bool polarity_change;
1099         int ret;
1100
1101         for (i = 0; i < lr->num_lines; i++) {
1102                 desc = lr->lines[i].desc;
1103                 flags = gpio_v2_line_config_flags(lc, i);
1104                 polarity_change =
1105                         (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) !=
1106                          ((flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) != 0));
1107
1108                 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1109                 /*
1110                  * Lines have to be requested explicitly for input
1111                  * or output, else the line will be treated "as is".
1112                  */
1113                 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1114                         int val = gpio_v2_line_config_output_value(lc, i);
1115
1116                         edge_detector_stop(&lr->lines[i]);
1117                         ret = gpiod_direction_output(desc, val);
1118                         if (ret)
1119                                 return ret;
1120                 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1121                         ret = gpiod_direction_input(desc);
1122                         if (ret)
1123                                 return ret;
1124
1125                         ret = edge_detector_update(&lr->lines[i], lc, i,
1126                                         flags & GPIO_V2_LINE_EDGE_FLAGS,
1127                                         polarity_change);
1128                         if (ret)
1129                                 return ret;
1130                 }
1131
1132                 blocking_notifier_call_chain(&desc->gdev->notifier,
1133                                              GPIO_V2_LINE_CHANGED_CONFIG,
1134                                              desc);
1135         }
1136         return 0;
1137 }
1138
1139 static long linereq_set_config(struct linereq *lr, void __user *ip)
1140 {
1141         struct gpio_v2_line_config lc;
1142         int ret;
1143
1144         if (copy_from_user(&lc, ip, sizeof(lc)))
1145                 return -EFAULT;
1146
1147         ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
1148         if (ret)
1149                 return ret;
1150
1151         mutex_lock(&lr->config_mutex);
1152
1153         ret = linereq_set_config_unlocked(lr, &lc);
1154
1155         mutex_unlock(&lr->config_mutex);
1156
1157         return ret;
1158 }
1159
1160 static long linereq_ioctl(struct file *file, unsigned int cmd,
1161                           unsigned long arg)
1162 {
1163         struct linereq *lr = file->private_data;
1164         void __user *ip = (void __user *)arg;
1165
1166         if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL)
1167                 return linereq_get_values(lr, ip);
1168         else if (cmd == GPIO_V2_LINE_SET_VALUES_IOCTL)
1169                 return linereq_set_values(lr, ip);
1170         else if (cmd == GPIO_V2_LINE_SET_CONFIG_IOCTL)
1171                 return linereq_set_config(lr, ip);
1172
1173         return -EINVAL;
1174 }
1175
1176 #ifdef CONFIG_COMPAT
1177 static long linereq_ioctl_compat(struct file *file, unsigned int cmd,
1178                                  unsigned long arg)
1179 {
1180         return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1181 }
1182 #endif
1183
1184 static __poll_t linereq_poll(struct file *file,
1185                             struct poll_table_struct *wait)
1186 {
1187         struct linereq *lr = file->private_data;
1188         __poll_t events = 0;
1189
1190         poll_wait(file, &lr->wait, wait);
1191
1192         if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events,
1193                                                  &lr->wait.lock))
1194                 events = EPOLLIN | EPOLLRDNORM;
1195
1196         return events;
1197 }
1198
1199 static ssize_t linereq_read(struct file *file,
1200                             char __user *buf,
1201                             size_t count,
1202                             loff_t *f_ps)
1203 {
1204         struct linereq *lr = file->private_data;
1205         struct gpio_v2_line_event le;
1206         ssize_t bytes_read = 0;
1207         int ret;
1208
1209         if (count < sizeof(le))
1210                 return -EINVAL;
1211
1212         do {
1213                 spin_lock(&lr->wait.lock);
1214                 if (kfifo_is_empty(&lr->events)) {
1215                         if (bytes_read) {
1216                                 spin_unlock(&lr->wait.lock);
1217                                 return bytes_read;
1218                         }
1219
1220                         if (file->f_flags & O_NONBLOCK) {
1221                                 spin_unlock(&lr->wait.lock);
1222                                 return -EAGAIN;
1223                         }
1224
1225                         ret = wait_event_interruptible_locked(lr->wait,
1226                                         !kfifo_is_empty(&lr->events));
1227                         if (ret) {
1228                                 spin_unlock(&lr->wait.lock);
1229                                 return ret;
1230                         }
1231                 }
1232
1233                 ret = kfifo_out(&lr->events, &le, 1);
1234                 spin_unlock(&lr->wait.lock);
1235                 if (ret != 1) {
1236                         /*
1237                          * This should never happen - we were holding the
1238                          * lock from the moment we learned the fifo is no
1239                          * longer empty until now.
1240                          */
1241                         ret = -EIO;
1242                         break;
1243                 }
1244
1245                 if (copy_to_user(buf + bytes_read, &le, sizeof(le)))
1246                         return -EFAULT;
1247                 bytes_read += sizeof(le);
1248         } while (count >= bytes_read + sizeof(le));
1249
1250         return bytes_read;
1251 }
1252
1253 static void linereq_free(struct linereq *lr)
1254 {
1255         unsigned int i;
1256
1257         for (i = 0; i < lr->num_lines; i++) {
1258                 edge_detector_stop(&lr->lines[i]);
1259                 if (lr->lines[i].desc)
1260                         gpiod_free(lr->lines[i].desc);
1261         }
1262         kfifo_free(&lr->events);
1263         kfree(lr->label);
1264         put_device(&lr->gdev->dev);
1265         kfree(lr);
1266 }
1267
1268 static int linereq_release(struct inode *inode, struct file *file)
1269 {
1270         struct linereq *lr = file->private_data;
1271
1272         linereq_free(lr);
1273         return 0;
1274 }
1275
1276 static const struct file_operations line_fileops = {
1277         .release = linereq_release,
1278         .read = linereq_read,
1279         .poll = linereq_poll,
1280         .owner = THIS_MODULE,
1281         .llseek = noop_llseek,
1282         .unlocked_ioctl = linereq_ioctl,
1283 #ifdef CONFIG_COMPAT
1284         .compat_ioctl = linereq_ioctl_compat,
1285 #endif
1286 };
1287
1288 static int linereq_create(struct gpio_device *gdev, void __user *ip)
1289 {
1290         struct gpio_v2_line_request ulr;
1291         struct gpio_v2_line_config *lc;
1292         struct linereq *lr;
1293         struct file *file;
1294         u64 flags;
1295         unsigned int i;
1296         int fd, ret;
1297
1298         if (copy_from_user(&ulr, ip, sizeof(ulr)))
1299                 return -EFAULT;
1300
1301         if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
1302                 return -EINVAL;
1303
1304         if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding)))
1305                 return -EINVAL;
1306
1307         lc = &ulr.config;
1308         ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
1309         if (ret)
1310                 return ret;
1311
1312         lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
1313         if (!lr)
1314                 return -ENOMEM;
1315
1316         lr->gdev = gdev;
1317         get_device(&gdev->dev);
1318
1319         for (i = 0; i < ulr.num_lines; i++) {
1320                 lr->lines[i].req = lr;
1321                 WRITE_ONCE(lr->lines[i].sw_debounced, 0);
1322                 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
1323         }
1324
1325         if (ulr.consumer[0] != '\0') {
1326                 /* label is only initialized if consumer is set */
1327                 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
1328                                      GFP_KERNEL);
1329                 if (!lr->label) {
1330                         ret = -ENOMEM;
1331                         goto out_free_linereq;
1332                 }
1333         }
1334
1335         mutex_init(&lr->config_mutex);
1336         init_waitqueue_head(&lr->wait);
1337         lr->event_buffer_size = ulr.event_buffer_size;
1338         if (lr->event_buffer_size == 0)
1339                 lr->event_buffer_size = ulr.num_lines * 16;
1340         else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16)
1341                 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;
1342
1343         atomic_set(&lr->seqno, 0);
1344         lr->num_lines = ulr.num_lines;
1345
1346         /* Request each GPIO */
1347         for (i = 0; i < ulr.num_lines; i++) {
1348                 u32 offset = ulr.offsets[i];
1349                 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
1350
1351                 if (IS_ERR(desc)) {
1352                         ret = PTR_ERR(desc);
1353                         goto out_free_linereq;
1354                 }
1355
1356                 ret = gpiod_request(desc, lr->label);
1357                 if (ret)
1358                         goto out_free_linereq;
1359
1360                 lr->lines[i].desc = desc;
1361                 flags = gpio_v2_line_config_flags(lc, i);
1362                 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1363
1364                 ret = gpiod_set_transitory(desc, false);
1365                 if (ret < 0)
1366                         goto out_free_linereq;
1367
1368                 /*
1369                  * Lines have to be requested explicitly for input
1370                  * or output, else the line will be treated "as is".
1371                  */
1372                 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1373                         int val = gpio_v2_line_config_output_value(lc, i);
1374
1375                         ret = gpiod_direction_output(desc, val);
1376                         if (ret)
1377                                 goto out_free_linereq;
1378                 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1379                         ret = gpiod_direction_input(desc);
1380                         if (ret)
1381                                 goto out_free_linereq;
1382
1383                         ret = edge_detector_setup(&lr->lines[i], lc, i,
1384                                         flags & GPIO_V2_LINE_EDGE_FLAGS);
1385                         if (ret)
1386                                 goto out_free_linereq;
1387                 }
1388
1389                 blocking_notifier_call_chain(&desc->gdev->notifier,
1390                                              GPIO_V2_LINE_CHANGED_REQUESTED, desc);
1391
1392                 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
1393                         offset);
1394         }
1395
1396         fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
1397         if (fd < 0) {
1398                 ret = fd;
1399                 goto out_free_linereq;
1400         }
1401
1402         file = anon_inode_getfile("gpio-line", &line_fileops, lr,
1403                                   O_RDONLY | O_CLOEXEC);
1404         if (IS_ERR(file)) {
1405                 ret = PTR_ERR(file);
1406                 goto out_put_unused_fd;
1407         }
1408
1409         ulr.fd = fd;
1410         if (copy_to_user(ip, &ulr, sizeof(ulr))) {
1411                 /*
1412                  * fput() will trigger the release() callback, so do not go onto
1413                  * the regular error cleanup path here.
1414                  */
1415                 fput(file);
1416                 put_unused_fd(fd);
1417                 return -EFAULT;
1418         }
1419
1420         fd_install(fd, file);
1421
1422         dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
1423                 lr->num_lines);
1424
1425         return 0;
1426
1427 out_put_unused_fd:
1428         put_unused_fd(fd);
1429 out_free_linereq:
1430         linereq_free(lr);
1431         return ret;
1432 }
1433
1434 #ifdef CONFIG_GPIO_CDEV_V1
1435
1436 /*
1437  * GPIO line event management
1438  */
1439
1440 /**
1441  * struct lineevent_state - contains the state of a userspace event
1442  * @gdev: the GPIO device the event pertains to
1443  * @label: consumer label used to tag descriptors
1444  * @desc: the GPIO descriptor held by this event
1445  * @eflags: the event flags this line was requested with
1446  * @irq: the interrupt that trigger in response to events on this GPIO
1447  * @wait: wait queue that handles blocking reads of events
1448  * @events: KFIFO for the GPIO events
1449  * @timestamp: cache for the timestamp storing it between hardirq
1450  * and IRQ thread, used to bring the timestamp close to the actual
1451  * event
1452  */
1453 struct lineevent_state {
1454         struct gpio_device *gdev;
1455         const char *label;
1456         struct gpio_desc *desc;
1457         u32 eflags;
1458         int irq;
1459         wait_queue_head_t wait;
1460         DECLARE_KFIFO(events, struct gpioevent_data, 16);
1461         u64 timestamp;
1462 };
1463
1464 #define GPIOEVENT_REQUEST_VALID_FLAGS \
1465         (GPIOEVENT_REQUEST_RISING_EDGE | \
1466         GPIOEVENT_REQUEST_FALLING_EDGE)
1467
1468 static __poll_t lineevent_poll(struct file *file,
1469                                struct poll_table_struct *wait)
1470 {
1471         struct lineevent_state *le = file->private_data;
1472         __poll_t events = 0;
1473
1474         poll_wait(file, &le->wait, wait);
1475
1476         if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
1477                 events = EPOLLIN | EPOLLRDNORM;
1478
1479         return events;
1480 }
1481
1482 static ssize_t lineevent_get_size(void)
1483 {
1484 #if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
1485         /* i386 has no padding after 'id' */
1486         if (in_ia32_syscall()) {
1487                 struct compat_gpioeevent_data {
1488                         compat_u64      timestamp;
1489                         u32             id;
1490                 };
1491
1492                 return sizeof(struct compat_gpioeevent_data);
1493         }
1494 #endif
1495         return sizeof(struct gpioevent_data);
1496 }
1497
1498 static ssize_t lineevent_read(struct file *file,
1499                               char __user *buf,
1500                               size_t count,
1501                               loff_t *f_ps)
1502 {
1503         struct lineevent_state *le = file->private_data;
1504         struct gpioevent_data ge;
1505         ssize_t bytes_read = 0;
1506         ssize_t ge_size;
1507         int ret;
1508
1509         /*
1510          * When compatible system call is being used the struct gpioevent_data,
1511          * in case of at least ia32, has different size due to the alignment
1512          * differences. Because we have first member 64 bits followed by one of
1513          * 32 bits there is no gap between them. The only difference is the
1514          * padding at the end of the data structure. Hence, we calculate the
1515          * actual sizeof() and pass this as an argument to copy_to_user() to
1516          * drop unneeded bytes from the output.
1517          */
1518         ge_size = lineevent_get_size();
1519         if (count < ge_size)
1520                 return -EINVAL;
1521
1522         do {
1523                 spin_lock(&le->wait.lock);
1524                 if (kfifo_is_empty(&le->events)) {
1525                         if (bytes_read) {
1526                                 spin_unlock(&le->wait.lock);
1527                                 return bytes_read;
1528                         }
1529
1530                         if (file->f_flags & O_NONBLOCK) {
1531                                 spin_unlock(&le->wait.lock);
1532                                 return -EAGAIN;
1533                         }
1534
1535                         ret = wait_event_interruptible_locked(le->wait,
1536                                         !kfifo_is_empty(&le->events));
1537                         if (ret) {
1538                                 spin_unlock(&le->wait.lock);
1539                                 return ret;
1540                         }
1541                 }
1542
1543                 ret = kfifo_out(&le->events, &ge, 1);
1544                 spin_unlock(&le->wait.lock);
1545                 if (ret != 1) {
1546                         /*
1547                          * This should never happen - we were holding the lock
1548                          * from the moment we learned the fifo is no longer
1549                          * empty until now.
1550                          */
1551                         ret = -EIO;
1552                         break;
1553                 }
1554
1555                 if (copy_to_user(buf + bytes_read, &ge, ge_size))
1556                         return -EFAULT;
1557                 bytes_read += ge_size;
1558         } while (count >= bytes_read + ge_size);
1559
1560         return bytes_read;
1561 }
1562
1563 static void lineevent_free(struct lineevent_state *le)
1564 {
1565         if (le->irq)
1566                 free_irq(le->irq, le);
1567         if (le->desc)
1568                 gpiod_free(le->desc);
1569         kfree(le->label);
1570         put_device(&le->gdev->dev);
1571         kfree(le);
1572 }
1573
1574 static int lineevent_release(struct inode *inode, struct file *file)
1575 {
1576         lineevent_free(file->private_data);
1577         return 0;
1578 }
1579
1580 static long lineevent_ioctl(struct file *file, unsigned int cmd,
1581                             unsigned long arg)
1582 {
1583         struct lineevent_state *le = file->private_data;
1584         void __user *ip = (void __user *)arg;
1585         struct gpiohandle_data ghd;
1586
1587         /*
1588          * We can get the value for an event line but not set it,
1589          * because it is input by definition.
1590          */
1591         if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
1592                 int val;
1593
1594                 memset(&ghd, 0, sizeof(ghd));
1595
1596                 val = gpiod_get_value_cansleep(le->desc);
1597                 if (val < 0)
1598                         return val;
1599                 ghd.values[0] = val;
1600
1601                 if (copy_to_user(ip, &ghd, sizeof(ghd)))
1602                         return -EFAULT;
1603
1604                 return 0;
1605         }
1606         return -EINVAL;
1607 }
1608
1609 #ifdef CONFIG_COMPAT
1610 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd,
1611                                    unsigned long arg)
1612 {
1613         return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1614 }
1615 #endif
1616
1617 static const struct file_operations lineevent_fileops = {
1618         .release = lineevent_release,
1619         .read = lineevent_read,
1620         .poll = lineevent_poll,
1621         .owner = THIS_MODULE,
1622         .llseek = noop_llseek,
1623         .unlocked_ioctl = lineevent_ioctl,
1624 #ifdef CONFIG_COMPAT
1625         .compat_ioctl = lineevent_ioctl_compat,
1626 #endif
1627 };
1628
1629 static irqreturn_t lineevent_irq_thread(int irq, void *p)
1630 {
1631         struct lineevent_state *le = p;
1632         struct gpioevent_data ge;
1633         int ret;
1634
1635         /* Do not leak kernel stack to userspace */
1636         memset(&ge, 0, sizeof(ge));
1637
1638         /*
1639          * We may be running from a nested threaded interrupt in which case
1640          * we didn't get the timestamp from lineevent_irq_handler().
1641          */
1642         if (!le->timestamp)
1643                 ge.timestamp = ktime_get_ns();
1644         else
1645                 ge.timestamp = le->timestamp;
1646
1647         if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
1648             && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
1649                 int level = gpiod_get_value_cansleep(le->desc);
1650
1651                 if (level)
1652                         /* Emit low-to-high event */
1653                         ge.id = GPIOEVENT_EVENT_RISING_EDGE;
1654                 else
1655                         /* Emit high-to-low event */
1656                         ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
1657         } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
1658                 /* Emit low-to-high event */
1659                 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
1660         } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
1661                 /* Emit high-to-low event */
1662                 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
1663         } else {
1664                 return IRQ_NONE;
1665         }
1666
1667         ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
1668                                             1, &le->wait.lock);
1669         if (ret)
1670                 wake_up_poll(&le->wait, EPOLLIN);
1671         else
1672                 pr_debug_ratelimited("event FIFO is full - event dropped\n");
1673
1674         return IRQ_HANDLED;
1675 }
1676
1677 static irqreturn_t lineevent_irq_handler(int irq, void *p)
1678 {
1679         struct lineevent_state *le = p;
1680
1681         /*
1682          * Just store the timestamp in hardirq context so we get it as
1683          * close in time as possible to the actual event.
1684          */
1685         le->timestamp = ktime_get_ns();
1686
1687         return IRQ_WAKE_THREAD;
1688 }
1689
1690 static int lineevent_create(struct gpio_device *gdev, void __user *ip)
1691 {
1692         struct gpioevent_request eventreq;
1693         struct lineevent_state *le;
1694         struct gpio_desc *desc;
1695         struct file *file;
1696         u32 offset;
1697         u32 lflags;
1698         u32 eflags;
1699         int fd;
1700         int ret;
1701         int irq, irqflags = 0;
1702
1703         if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
1704                 return -EFAULT;
1705
1706         offset = eventreq.lineoffset;
1707         lflags = eventreq.handleflags;
1708         eflags = eventreq.eventflags;
1709
1710         desc = gpiochip_get_desc(gdev->chip, offset);
1711         if (IS_ERR(desc))
1712                 return PTR_ERR(desc);
1713
1714         /* Return an error if a unknown flag is set */
1715         if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
1716             (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
1717                 return -EINVAL;
1718
1719         /* This is just wrong: we don't look for events on output lines */
1720         if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
1721             (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
1722             (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
1723                 return -EINVAL;
1724
1725         /* Only one bias flag can be set. */
1726         if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
1727              (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
1728                         GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
1729             ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
1730              (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
1731                 return -EINVAL;
1732
1733         le = kzalloc(sizeof(*le), GFP_KERNEL);
1734         if (!le)
1735                 return -ENOMEM;
1736         le->gdev = gdev;
1737         get_device(&gdev->dev);
1738
1739         if (eventreq.consumer_label[0] != '\0') {
1740                 /* label is only initialized if consumer_label is set */
1741                 le->label = kstrndup(eventreq.consumer_label,
1742                                      sizeof(eventreq.consumer_label) - 1,
1743                                      GFP_KERNEL);
1744                 if (!le->label) {
1745                         ret = -ENOMEM;
1746                         goto out_free_le;
1747                 }
1748         }
1749
1750         ret = gpiod_request(desc, le->label);
1751         if (ret)
1752                 goto out_free_le;
1753         le->desc = desc;
1754         le->eflags = eflags;
1755
1756         linehandle_flags_to_desc_flags(lflags, &desc->flags);
1757
1758         ret = gpiod_direction_input(desc);
1759         if (ret)
1760                 goto out_free_le;
1761
1762         blocking_notifier_call_chain(&desc->gdev->notifier,
1763                                      GPIO_V2_LINE_CHANGED_REQUESTED, desc);
1764
1765         irq = gpiod_to_irq(desc);
1766         if (irq <= 0) {
1767                 ret = -ENODEV;
1768                 goto out_free_le;
1769         }
1770         le->irq = irq;
1771
1772         if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
1773                 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
1774                         IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
1775         if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
1776                 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
1777                         IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
1778         irqflags |= IRQF_ONESHOT;
1779
1780         INIT_KFIFO(le->events);
1781         init_waitqueue_head(&le->wait);
1782
1783         /* Request a thread to read the events */
1784         ret = request_threaded_irq(le->irq,
1785                                    lineevent_irq_handler,
1786                                    lineevent_irq_thread,
1787                                    irqflags,
1788                                    le->label,
1789                                    le);
1790         if (ret)
1791                 goto out_free_le;
1792
1793         fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
1794         if (fd < 0) {
1795                 ret = fd;
1796                 goto out_free_le;
1797         }
1798
1799         file = anon_inode_getfile("gpio-event",
1800                                   &lineevent_fileops,
1801                                   le,
1802                                   O_RDONLY | O_CLOEXEC);
1803         if (IS_ERR(file)) {
1804                 ret = PTR_ERR(file);
1805                 goto out_put_unused_fd;
1806         }
1807
1808         eventreq.fd = fd;
1809         if (copy_to_user(ip, &eventreq, sizeof(eventreq))) {
1810                 /*
1811                  * fput() will trigger the release() callback, so do not go onto
1812                  * the regular error cleanup path here.
1813                  */
1814                 fput(file);
1815                 put_unused_fd(fd);
1816                 return -EFAULT;
1817         }
1818
1819         fd_install(fd, file);
1820
1821         return 0;
1822
1823 out_put_unused_fd:
1824         put_unused_fd(fd);
1825 out_free_le:
1826         lineevent_free(le);
1827         return ret;
1828 }
1829
1830 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2,
1831                                     struct gpioline_info *info_v1)
1832 {
1833         u64 flagsv2 = info_v2->flags;
1834
1835         memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name));
1836         memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer));
1837         info_v1->line_offset = info_v2->offset;
1838         info_v1->flags = 0;
1839
1840         if (flagsv2 & GPIO_V2_LINE_FLAG_USED)
1841                 info_v1->flags |= GPIOLINE_FLAG_KERNEL;
1842
1843         if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT)
1844                 info_v1->flags |= GPIOLINE_FLAG_IS_OUT;
1845
1846         if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
1847                 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
1848
1849         if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN)
1850                 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN;
1851         if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE)
1852                 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE;
1853
1854         if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)
1855                 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
1856         if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN)
1857                 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
1858         if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED)
1859                 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
1860 }
1861
1862 static void gpio_v2_line_info_changed_to_v1(
1863                 struct gpio_v2_line_info_changed *lic_v2,
1864                 struct gpioline_info_changed *lic_v1)
1865 {
1866         gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info);
1867         lic_v1->timestamp = lic_v2->timestamp_ns;
1868         lic_v1->event_type = lic_v2->event_type;
1869 }
1870
1871 #endif /* CONFIG_GPIO_CDEV_V1 */
1872
1873 static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
1874                                   struct gpio_v2_line_info *info)
1875 {
1876         struct gpio_chip *gc = desc->gdev->chip;
1877         bool ok_for_pinctrl;
1878         unsigned long flags;
1879         u32 debounce_period_us;
1880         unsigned int num_attrs = 0;
1881
1882         memset(info, 0, sizeof(*info));
1883         info->offset = gpio_chip_hwgpio(desc);
1884
1885         /*
1886          * This function takes a mutex so we must check this before taking
1887          * the spinlock.
1888          *
1889          * FIXME: find a non-racy way to retrieve this information. Maybe a
1890          * lock common to both frameworks?
1891          */
1892         ok_for_pinctrl =
1893                 pinctrl_gpio_can_use_line(gc->base + info->offset);
1894
1895         spin_lock_irqsave(&gpio_lock, flags);
1896
1897         if (desc->name)
1898                 strscpy(info->name, desc->name, sizeof(info->name));
1899
1900         if (desc->label)
1901                 strscpy(info->consumer, desc->label, sizeof(info->consumer));
1902
1903         /*
1904          * Userspace only need to know that the kernel is using this GPIO so
1905          * it can't use it.
1906          */
1907         info->flags = 0;
1908         if (test_bit(FLAG_REQUESTED, &desc->flags) ||
1909             test_bit(FLAG_IS_HOGGED, &desc->flags) ||
1910             test_bit(FLAG_USED_AS_IRQ, &desc->flags) ||
1911             test_bit(FLAG_EXPORT, &desc->flags) ||
1912             test_bit(FLAG_SYSFS, &desc->flags) ||
1913             !ok_for_pinctrl)
1914                 info->flags |= GPIO_V2_LINE_FLAG_USED;
1915
1916         if (test_bit(FLAG_IS_OUT, &desc->flags))
1917                 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
1918         else
1919                 info->flags |= GPIO_V2_LINE_FLAG_INPUT;
1920
1921         if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1922                 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
1923
1924         if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
1925                 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
1926         if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
1927                 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
1928
1929         if (test_bit(FLAG_BIAS_DISABLE, &desc->flags))
1930                 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
1931         if (test_bit(FLAG_PULL_DOWN, &desc->flags))
1932                 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
1933         if (test_bit(FLAG_PULL_UP, &desc->flags))
1934                 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
1935
1936         if (test_bit(FLAG_EDGE_RISING, &desc->flags))
1937                 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
1938         if (test_bit(FLAG_EDGE_FALLING, &desc->flags))
1939                 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
1940
1941         debounce_period_us = READ_ONCE(desc->debounce_period_us);
1942         if (debounce_period_us) {
1943                 info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
1944                 info->attrs[num_attrs].debounce_period_us = debounce_period_us;
1945                 num_attrs++;
1946         }
1947         info->num_attrs = num_attrs;
1948
1949         spin_unlock_irqrestore(&gpio_lock, flags);
1950 }
1951
1952 struct gpio_chardev_data {
1953         struct gpio_device *gdev;
1954         wait_queue_head_t wait;
1955         DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32);
1956         struct notifier_block lineinfo_changed_nb;
1957         unsigned long *watched_lines;
1958 #ifdef CONFIG_GPIO_CDEV_V1
1959         atomic_t watch_abi_version;
1960 #endif
1961 };
1962
1963 #ifdef CONFIG_GPIO_CDEV_V1
1964 /*
1965  * returns 0 if the versions match, else the previously selected ABI version
1966  */
1967 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata,
1968                                        unsigned int version)
1969 {
1970         int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version);
1971
1972         if (abiv == version)
1973                 return 0;
1974
1975         return abiv;
1976 }
1977 #endif
1978
1979 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
1980                         bool watch)
1981 {
1982         struct gpio_desc *desc;
1983         struct gpio_v2_line_info lineinfo;
1984
1985         if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
1986                 return -EFAULT;
1987
1988         if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding)))
1989                 return -EINVAL;
1990
1991         desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset);
1992         if (IS_ERR(desc))
1993                 return PTR_ERR(desc);
1994
1995         if (watch) {
1996 #ifdef CONFIG_GPIO_CDEV_V1
1997                 if (lineinfo_ensure_abi_version(cdev, 2))
1998                         return -EPERM;
1999 #endif
2000                 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
2001                         return -EBUSY;
2002         }
2003         gpio_desc_to_lineinfo(desc, &lineinfo);
2004
2005         if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2006                 if (watch)
2007                         clear_bit(lineinfo.offset, cdev->watched_lines);
2008                 return -EFAULT;
2009         }
2010
2011         return 0;
2012 }
2013
2014 /*
2015  * gpio_ioctl() - ioctl handler for the GPIO chardev
2016  */
2017 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2018 {
2019         struct gpio_chardev_data *cdev = file->private_data;
2020         struct gpio_device *gdev = cdev->gdev;
2021         struct gpio_chip *gc = gdev->chip;
2022         void __user *ip = (void __user *)arg;
2023         __u32 offset;
2024
2025         /* We fail any subsequent ioctl():s when the chip is gone */
2026         if (!gc)
2027                 return -ENODEV;
2028
2029         /* Fill in the struct and pass to userspace */
2030         if (cmd == GPIO_GET_CHIPINFO_IOCTL) {
2031                 struct gpiochip_info chipinfo;
2032
2033                 memset(&chipinfo, 0, sizeof(chipinfo));
2034
2035                 strscpy(chipinfo.name, dev_name(&gdev->dev),
2036                         sizeof(chipinfo.name));
2037                 strscpy(chipinfo.label, gdev->label,
2038                         sizeof(chipinfo.label));
2039                 chipinfo.lines = gdev->ngpio;
2040                 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
2041                         return -EFAULT;
2042                 return 0;
2043 #ifdef CONFIG_GPIO_CDEV_V1
2044         } else if (cmd == GPIO_GET_LINEINFO_IOCTL) {
2045                 struct gpio_desc *desc;
2046                 struct gpioline_info lineinfo;
2047                 struct gpio_v2_line_info lineinfo_v2;
2048
2049                 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2050                         return -EFAULT;
2051
2052                 /* this doubles as a range check on line_offset */
2053                 desc = gpiochip_get_desc(gc, lineinfo.line_offset);
2054                 if (IS_ERR(desc))
2055                         return PTR_ERR(desc);
2056
2057                 gpio_desc_to_lineinfo(desc, &lineinfo_v2);
2058                 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
2059
2060                 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo)))
2061                         return -EFAULT;
2062                 return 0;
2063         } else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) {
2064                 return linehandle_create(gdev, ip);
2065         } else if (cmd == GPIO_GET_LINEEVENT_IOCTL) {
2066                 return lineevent_create(gdev, ip);
2067         } else if (cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) {
2068                 struct gpio_desc *desc;
2069                 struct gpioline_info lineinfo;
2070                 struct gpio_v2_line_info lineinfo_v2;
2071
2072                 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2073                         return -EFAULT;
2074
2075                 /* this doubles as a range check on line_offset */
2076                 desc = gpiochip_get_desc(gc, lineinfo.line_offset);
2077                 if (IS_ERR(desc))
2078                         return PTR_ERR(desc);
2079
2080                 if (lineinfo_ensure_abi_version(cdev, 1))
2081                         return -EPERM;
2082
2083                 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
2084                         return -EBUSY;
2085
2086                 gpio_desc_to_lineinfo(desc, &lineinfo_v2);
2087                 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
2088
2089                 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2090                         clear_bit(lineinfo.line_offset, cdev->watched_lines);
2091                         return -EFAULT;
2092                 }
2093
2094                 return 0;
2095 #endif /* CONFIG_GPIO_CDEV_V1 */
2096         } else if (cmd == GPIO_V2_GET_LINEINFO_IOCTL ||
2097                    cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL) {
2098                 return lineinfo_get(cdev, ip,
2099                                     cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL);
2100         } else if (cmd == GPIO_V2_GET_LINE_IOCTL) {
2101                 return linereq_create(gdev, ip);
2102         } else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) {
2103                 if (copy_from_user(&offset, ip, sizeof(offset)))
2104                         return -EFAULT;
2105
2106                 if (offset >= cdev->gdev->ngpio)
2107                         return -EINVAL;
2108
2109                 if (!test_and_clear_bit(offset, cdev->watched_lines))
2110                         return -EBUSY;
2111
2112                 return 0;
2113         }
2114         return -EINVAL;
2115 }
2116
2117 #ifdef CONFIG_COMPAT
2118 static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
2119                               unsigned long arg)
2120 {
2121         return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2122 }
2123 #endif
2124
2125 static struct gpio_chardev_data *
2126 to_gpio_chardev_data(struct notifier_block *nb)
2127 {
2128         return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
2129 }
2130
2131 static int lineinfo_changed_notify(struct notifier_block *nb,
2132                                    unsigned long action, void *data)
2133 {
2134         struct gpio_chardev_data *cdev = to_gpio_chardev_data(nb);
2135         struct gpio_v2_line_info_changed chg;
2136         struct gpio_desc *desc = data;
2137         int ret;
2138
2139         if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines))
2140                 return NOTIFY_DONE;
2141
2142         memset(&chg, 0, sizeof(chg));
2143         chg.event_type = action;
2144         chg.timestamp_ns = ktime_get_ns();
2145         gpio_desc_to_lineinfo(desc, &chg.info);
2146
2147         ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
2148         if (ret)
2149                 wake_up_poll(&cdev->wait, EPOLLIN);
2150         else
2151                 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");
2152
2153         return NOTIFY_OK;
2154 }
2155
2156 static __poll_t lineinfo_watch_poll(struct file *file,
2157                                     struct poll_table_struct *pollt)
2158 {
2159         struct gpio_chardev_data *cdev = file->private_data;
2160         __poll_t events = 0;
2161
2162         poll_wait(file, &cdev->wait, pollt);
2163
2164         if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events,
2165                                                  &cdev->wait.lock))
2166                 events = EPOLLIN | EPOLLRDNORM;
2167
2168         return events;
2169 }
2170
2171 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
2172                                    size_t count, loff_t *off)
2173 {
2174         struct gpio_chardev_data *cdev = file->private_data;
2175         struct gpio_v2_line_info_changed event;
2176         ssize_t bytes_read = 0;
2177         int ret;
2178         size_t event_size;
2179
2180 #ifndef CONFIG_GPIO_CDEV_V1
2181         event_size = sizeof(struct gpio_v2_line_info_changed);
2182         if (count < event_size)
2183                 return -EINVAL;
2184 #endif
2185
2186         do {
2187                 spin_lock(&cdev->wait.lock);
2188                 if (kfifo_is_empty(&cdev->events)) {
2189                         if (bytes_read) {
2190                                 spin_unlock(&cdev->wait.lock);
2191                                 return bytes_read;
2192                         }
2193
2194                         if (file->f_flags & O_NONBLOCK) {
2195                                 spin_unlock(&cdev->wait.lock);
2196                                 return -EAGAIN;
2197                         }
2198
2199                         ret = wait_event_interruptible_locked(cdev->wait,
2200                                         !kfifo_is_empty(&cdev->events));
2201                         if (ret) {
2202                                 spin_unlock(&cdev->wait.lock);
2203                                 return ret;
2204                         }
2205                 }
2206 #ifdef CONFIG_GPIO_CDEV_V1
2207                 /* must be after kfifo check so watch_abi_version is set */
2208                 if (atomic_read(&cdev->watch_abi_version) == 2)
2209                         event_size = sizeof(struct gpio_v2_line_info_changed);
2210                 else
2211                         event_size = sizeof(struct gpioline_info_changed);
2212                 if (count < event_size) {
2213                         spin_unlock(&cdev->wait.lock);
2214                         return -EINVAL;
2215                 }
2216 #endif
2217                 ret = kfifo_out(&cdev->events, &event, 1);
2218                 spin_unlock(&cdev->wait.lock);
2219                 if (ret != 1) {
2220                         ret = -EIO;
2221                         break;
2222                         /* We should never get here. See lineevent_read(). */
2223                 }
2224
2225 #ifdef CONFIG_GPIO_CDEV_V1
2226                 if (event_size == sizeof(struct gpio_v2_line_info_changed)) {
2227                         if (copy_to_user(buf + bytes_read, &event, event_size))
2228                                 return -EFAULT;
2229                 } else {
2230                         struct gpioline_info_changed event_v1;
2231
2232                         gpio_v2_line_info_changed_to_v1(&event, &event_v1);
2233                         if (copy_to_user(buf + bytes_read, &event_v1,
2234                                          event_size))
2235                                 return -EFAULT;
2236                 }
2237 #else
2238                 if (copy_to_user(buf + bytes_read, &event, event_size))
2239                         return -EFAULT;
2240 #endif
2241                 bytes_read += event_size;
2242         } while (count >= bytes_read + sizeof(event));
2243
2244         return bytes_read;
2245 }
2246
2247 /**
2248  * gpio_chrdev_open() - open the chardev for ioctl operations
2249  * @inode: inode for this chardev
2250  * @file: file struct for storing private data
2251  * Returns 0 on success
2252  */
2253 static int gpio_chrdev_open(struct inode *inode, struct file *file)
2254 {
2255         struct gpio_device *gdev = container_of(inode->i_cdev,
2256                                                 struct gpio_device, chrdev);
2257         struct gpio_chardev_data *cdev;
2258         int ret = -ENOMEM;
2259
2260         /* Fail on open if the backing gpiochip is gone */
2261         if (!gdev->chip)
2262                 return -ENODEV;
2263
2264         cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
2265         if (!cdev)
2266                 return -ENOMEM;
2267
2268         cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL);
2269         if (!cdev->watched_lines)
2270                 goto out_free_cdev;
2271
2272         init_waitqueue_head(&cdev->wait);
2273         INIT_KFIFO(cdev->events);
2274         cdev->gdev = gdev;
2275
2276         cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
2277         ret = blocking_notifier_chain_register(&gdev->notifier,
2278                                                &cdev->lineinfo_changed_nb);
2279         if (ret)
2280                 goto out_free_bitmap;
2281
2282         get_device(&gdev->dev);
2283         file->private_data = cdev;
2284
2285         ret = nonseekable_open(inode, file);
2286         if (ret)
2287                 goto out_unregister_notifier;
2288
2289         return ret;
2290
2291 out_unregister_notifier:
2292         blocking_notifier_chain_unregister(&gdev->notifier,
2293                                            &cdev->lineinfo_changed_nb);
2294 out_free_bitmap:
2295         bitmap_free(cdev->watched_lines);
2296 out_free_cdev:
2297         kfree(cdev);
2298         return ret;
2299 }
2300
2301 /**
2302  * gpio_chrdev_release() - close chardev after ioctl operations
2303  * @inode: inode for this chardev
2304  * @file: file struct for storing private data
2305  * Returns 0 on success
2306  */
2307 static int gpio_chrdev_release(struct inode *inode, struct file *file)
2308 {
2309         struct gpio_chardev_data *cdev = file->private_data;
2310         struct gpio_device *gdev = cdev->gdev;
2311
2312         bitmap_free(cdev->watched_lines);
2313         blocking_notifier_chain_unregister(&gdev->notifier,
2314                                            &cdev->lineinfo_changed_nb);
2315         put_device(&gdev->dev);
2316         kfree(cdev);
2317
2318         return 0;
2319 }
2320
2321 static const struct file_operations gpio_fileops = {
2322         .release = gpio_chrdev_release,
2323         .open = gpio_chrdev_open,
2324         .poll = lineinfo_watch_poll,
2325         .read = lineinfo_watch_read,
2326         .owner = THIS_MODULE,
2327         .llseek = no_llseek,
2328         .unlocked_ioctl = gpio_ioctl,
2329 #ifdef CONFIG_COMPAT
2330         .compat_ioctl = gpio_ioctl_compat,
2331 #endif
2332 };
2333
2334 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
2335 {
2336         int ret;
2337
2338         cdev_init(&gdev->chrdev, &gpio_fileops);
2339         gdev->chrdev.owner = THIS_MODULE;
2340         gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
2341
2342         ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
2343         if (ret)
2344                 return ret;
2345
2346         chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
2347                  MAJOR(devt), gdev->id);
2348
2349         return 0;
2350 }
2351
2352 void gpiolib_cdev_unregister(struct gpio_device *gdev)
2353 {
2354         cdev_device_del(&gdev->chrdev, &gdev->dev);
2355 }