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         if (line->desc)
 760                 WRITE_ONCE(line->desc->debounce_period_us, 0);
 761         /* do not change line->level - see comment in debounced_value() */
 762 }
 763
 764 static int edge_detector_setup(struct line *line,
 765                                struct gpio_v2_line_config *lc,
 766                                unsigned int line_idx,
 767                                u64 eflags)
 768 {
 769         u32 debounce_period_us;
 770         unsigned long irqflags = 0;
 771         int irq, ret;
 772
 773         if (eflags && !kfifo_initialized(&line->req->events)) {
 774                 ret = kfifo_alloc(&line->req->events,
 775                                   line->req->event_buffer_size, GFP_KERNEL);
 776                 if (ret)
 777                         return ret;
 778         }
 779         line->eflags = eflags;
 780         if (gpio_v2_line_config_debounced(lc, line_idx)) {
 781                 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
 782                 ret = debounce_setup(line, debounce_period_us);
 783                 if (ret)
 784                         return ret;
 785                 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
 786         }
 787
 788         /* detection disabled or sw debouncer will provide edge detection */
 789         if (!eflags || READ_ONCE(line->sw_debounced))
 790                 return 0;
 791
 792         irq = gpiod_to_irq(line->desc);
 793         if (irq < 0)
 794                 return -ENXIO;
 795
 796         if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
 797                 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
 798                         IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
 799         if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
 800                 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
 801                         IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
 802         irqflags |= IRQF_ONESHOT;
 803
 804         /* Request a thread to read the events */
 805         ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
 806                                    irqflags, line->req->label, line);
 807         if (ret)
 808                 return ret;
 809
 810         line->irq = irq;
 811         return 0;
 812 }
 813
 814 static int edge_detector_update(struct line *line,
 815                                 struct gpio_v2_line_config *lc,
 816                                 unsigned int line_idx,
 817                                 u64 eflags, bool polarity_change)
 818 {
 819         unsigned int debounce_period_us =
 820                 gpio_v2_line_config_debounce_period(lc, line_idx);
 821
 822         if ((line->eflags == eflags) && !polarity_change &&
 823             (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us))
 824                 return 0;
 825
 826         /* sw debounced and still will be...*/
 827         if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
 828                 line->eflags = eflags;
 829                 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
 830                 return 0;
 831         }
 832
 833         /* reconfiguring edge detection or sw debounce being disabled */
 834         if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
 835             (!debounce_period_us && READ_ONCE(line->sw_debounced)))
 836                 edge_detector_stop(line);
 837
 838         return edge_detector_setup(line, lc, line_idx, eflags);
 839 }
 840
 841 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
 842                                      unsigned int line_idx)
 843 {
 844         unsigned int i;
 845         u64 mask = BIT_ULL(line_idx);
 846
 847         for (i = 0; i < lc->num_attrs; i++) {
 848                 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) &&
 849                     (lc->attrs[i].mask & mask))
 850                         return lc->attrs[i].attr.flags;
 851         }
 852         return lc->flags;
 853 }
 854
 855 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc,
 856                                             unsigned int line_idx)
 857 {
 858         unsigned int i;
 859         u64 mask = BIT_ULL(line_idx);
 860
 861         for (i = 0; i < lc->num_attrs; i++) {
 862                 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) &&
 863                     (lc->attrs[i].mask & mask))
 864                         return !!(lc->attrs[i].attr.values & mask);
 865         }
 866         return 0;
 867 }
 868
 869 static int gpio_v2_line_flags_validate(u64 flags)
 870 {
 871         /* Return an error if an unknown flag is set */
 872         if (flags & ~GPIO_V2_LINE_VALID_FLAGS)
 873                 return -EINVAL;
 874
 875         /*
 876          * Do not allow both INPUT and OUTPUT flags to be set as they are
 877          * contradictory.
 878          */
 879         if ((flags & GPIO_V2_LINE_FLAG_INPUT) &&
 880             (flags & GPIO_V2_LINE_FLAG_OUTPUT))
 881                 return -EINVAL;
 882
 883         /* Edge detection requires explicit input. */
 884         if ((flags & GPIO_V2_LINE_EDGE_FLAGS) &&
 885             !(flags & GPIO_V2_LINE_FLAG_INPUT))
 886                 return -EINVAL;
 887
 888         /*
 889          * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single
 890          * request. If the hardware actually supports enabling both at the
 891          * same time the electrical result would be disastrous.
 892          */
 893         if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) &&
 894             (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE))
 895                 return -EINVAL;
 896
 897         /* Drive requires explicit output direction. */
 898         if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) &&
 899             !(flags & GPIO_V2_LINE_FLAG_OUTPUT))
 900                 return -EINVAL;
 901
 902         /* Bias requires explicit direction. */
 903         if ((flags & GPIO_V2_LINE_BIAS_FLAGS) &&
 904             !(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
 905                 return -EINVAL;
 906
 907         /* Only one bias flag can be set. */
 908         if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) &&
 909              (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN |
 910                        GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) ||
 911             ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) &&
 912              (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)))
 913                 return -EINVAL;
 914
 915         return 0;
 916 }
 917
 918 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
 919                                         unsigned int num_lines)
 920 {
 921         unsigned int i;
 922         u64 flags;
 923         int ret;
 924
 925         if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX)
 926                 return -EINVAL;
 927
 928         if (memchr_inv(lc->padding, 0, sizeof(lc->padding)))
 929                 return -EINVAL;
 930
 931         for (i = 0; i < num_lines; i++) {
 932                 flags = gpio_v2_line_config_flags(lc, i);
 933                 ret = gpio_v2_line_flags_validate(flags);
 934                 if (ret)
 935                         return ret;
 936
 937                 /* debounce requires explicit input */
 938                 if (gpio_v2_line_config_debounced(lc, i) &&
 939                     !(flags & GPIO_V2_LINE_FLAG_INPUT))
 940                         return -EINVAL;
 941         }
 942         return 0;
 943 }
 944
 945 static void gpio_v2_line_config_flags_to_desc_flags(u64 flags,
 946                                                     unsigned long *flagsp)
 947 {
 948         assign_bit(FLAG_ACTIVE_LOW, flagsp,
 949                    flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW);
 950
 951         if (flags & GPIO_V2_LINE_FLAG_OUTPUT)
 952                 set_bit(FLAG_IS_OUT, flagsp);
 953         else if (flags & GPIO_V2_LINE_FLAG_INPUT)
 954                 clear_bit(FLAG_IS_OUT, flagsp);
 955
 956         assign_bit(FLAG_EDGE_RISING, flagsp,
 957                    flags & GPIO_V2_LINE_FLAG_EDGE_RISING);
 958         assign_bit(FLAG_EDGE_FALLING, flagsp,
 959                    flags & GPIO_V2_LINE_FLAG_EDGE_FALLING);
 960
 961         assign_bit(FLAG_OPEN_DRAIN, flagsp,
 962                    flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN);
 963         assign_bit(FLAG_OPEN_SOURCE, flagsp,
 964                    flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE);
 965
 966         assign_bit(FLAG_PULL_UP, flagsp,
 967                    flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP);
 968         assign_bit(FLAG_PULL_DOWN, flagsp,
 969                    flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN);
 970         assign_bit(FLAG_BIAS_DISABLE, flagsp,
 971                    flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED);
 972 }
 973
 974 static long linereq_get_values(struct linereq *lr, void __user *ip)
 975 {
 976         struct gpio_v2_line_values lv;
 977         DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
 978         struct gpio_desc **descs;
 979         unsigned int i, didx, num_get;
 980         bool val;
 981         int ret;
 982
 983         /* NOTE: It's ok to read values of output lines. */
 984         if (copy_from_user(&lv, ip, sizeof(lv)))
 985                 return -EFAULT;
 986
 987         for (num_get = 0, i = 0; i < lr->num_lines; i++) {
 988                 if (lv.mask & BIT_ULL(i)) {
 989                         num_get++;
 990                         descs = &lr->lines[i].desc;
 991                 }
 992         }
 993
 994         if (num_get == 0)
 995                 return -EINVAL;
 996
 997         if (num_get != 1) {
 998                 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL);
 999                 if (!descs)
1000                         return -ENOMEM;
1001                 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1002                         if (lv.mask & BIT_ULL(i)) {
1003                                 descs[didx] = lr->lines[i].desc;
1004                                 didx++;
1005                         }
1006                 }
1007         }
1008         ret = gpiod_get_array_value_complex(false, true, num_get,
1009                                             descs, NULL, vals);
1010
1011         if (num_get != 1)
1012                 kfree(descs);
1013         if (ret)
1014                 return ret;
1015
1016         lv.bits = 0;
1017         for (didx = 0, i = 0; i < lr->num_lines; i++) {
1018                 if (lv.mask & BIT_ULL(i)) {
1019                         if (lr->lines[i].sw_debounced)
1020                                 val = debounced_value(&lr->lines[i]);
1021                         else
1022                                 val = test_bit(didx, vals);
1023                         if (val)
1024                                 lv.bits |= BIT_ULL(i);
1025                         didx++;
1026                 }
1027         }
1028
1029         if (copy_to_user(ip, &lv, sizeof(lv)))
1030                 return -EFAULT;
1031
1032         return 0;
1033 }
1034
1035 static long linereq_set_values_unlocked(struct linereq *lr,
1036                                         struct gpio_v2_line_values *lv)
1037 {
1038         DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1039         struct gpio_desc **descs;
1040         unsigned int i, didx, num_set;
1041         int ret;
1042
1043         bitmap_zero(vals, GPIO_V2_LINES_MAX);
1044         for (num_set = 0, i = 0; i < lr->num_lines; i++) {
1045                 if (lv->mask & BIT_ULL(i)) {
1046                         if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
1047                                 return -EPERM;
1048                         if (lv->bits & BIT_ULL(i))
1049                                 __set_bit(num_set, vals);
1050                         num_set++;
1051                         descs = &lr->lines[i].desc;
1052                 }
1053         }
1054         if (num_set == 0)
1055                 return -EINVAL;
1056
1057         if (num_set != 1) {
1058                 /* build compacted desc array and values */
1059                 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);
1060                 if (!descs)
1061                         return -ENOMEM;
1062                 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1063                         if (lv->mask & BIT_ULL(i)) {
1064                                 descs[didx] = lr->lines[i].desc;
1065                                 didx++;
1066                         }
1067                 }
1068         }
1069         ret = gpiod_set_array_value_complex(false, true, num_set,
1070                                             descs, NULL, vals);
1071
1072         if (num_set != 1)
1073                 kfree(descs);
1074         return ret;
1075 }
1076
1077 static long linereq_set_values(struct linereq *lr, void __user *ip)
1078 {
1079         struct gpio_v2_line_values lv;
1080         int ret;
1081
1082         if (copy_from_user(&lv, ip, sizeof(lv)))
1083                 return -EFAULT;
1084
1085         mutex_lock(&lr->config_mutex);
1086
1087         ret = linereq_set_values_unlocked(lr, &lv);
1088
1089         mutex_unlock(&lr->config_mutex);
1090
1091         return ret;
1092 }
1093
1094 static long linereq_set_config_unlocked(struct linereq *lr,
1095                                         struct gpio_v2_line_config *lc)
1096 {
1097         struct gpio_desc *desc;
1098         unsigned int i;
1099         u64 flags;
1100         bool polarity_change;
1101         int ret;
1102
1103         for (i = 0; i < lr->num_lines; i++) {
1104                 desc = lr->lines[i].desc;
1105                 flags = gpio_v2_line_config_flags(lc, i);
1106                 polarity_change =
1107                         (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) !=
1108                          ((flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) != 0));
1109
1110                 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1111                 /*
1112                  * Lines have to be requested explicitly for input
1113                  * or output, else the line will be treated "as is".
1114                  */
1115                 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1116                         int val = gpio_v2_line_config_output_value(lc, i);
1117
1118                         edge_detector_stop(&lr->lines[i]);
1119                         ret = gpiod_direction_output(desc, val);
1120                         if (ret)
1121                                 return ret;
1122                 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1123                         ret = gpiod_direction_input(desc);
1124                         if (ret)
1125                                 return ret;
1126
1127                         ret = edge_detector_update(&lr->lines[i], lc, i,
1128                                         flags & GPIO_V2_LINE_EDGE_FLAGS,
1129                                         polarity_change);
1130                         if (ret)
1131                                 return ret;
1132                 }
1133
1134                 blocking_notifier_call_chain(&desc->gdev->notifier,
1135                                              GPIO_V2_LINE_CHANGED_CONFIG,
1136                                              desc);
1137         }
1138         return 0;
1139 }
1140
1141 static long linereq_set_config(struct linereq *lr, void __user *ip)
1142 {
1143         struct gpio_v2_line_config lc;
1144         int ret;
1145
1146         if (copy_from_user(&lc, ip, sizeof(lc)))
1147                 return -EFAULT;
1148
1149         ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
1150         if (ret)
1151                 return ret;
1152
1153         mutex_lock(&lr->config_mutex);
1154
1155         ret = linereq_set_config_unlocked(lr, &lc);
1156
1157         mutex_unlock(&lr->config_mutex);
1158
1159         return ret;
1160 }
1161
1162 static long linereq_ioctl(struct file *file, unsigned int cmd,
1163                           unsigned long arg)
1164 {
1165         struct linereq *lr = file->private_data;
1166         void __user *ip = (void __user *)arg;
1167
1168         if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL)
1169                 return linereq_get_values(lr, ip);
1170         else if (cmd == GPIO_V2_LINE_SET_VALUES_IOCTL)
1171                 return linereq_set_values(lr, ip);
1172         else if (cmd == GPIO_V2_LINE_SET_CONFIG_IOCTL)
1173                 return linereq_set_config(lr, ip);
1174
1175         return -EINVAL;
1176 }
1177
1178 #ifdef CONFIG_COMPAT
1179 static long linereq_ioctl_compat(struct file *file, unsigned int cmd,
1180                                  unsigned long arg)
1181 {
1182         return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1183 }
1184 #endif
1185
1186 static __poll_t linereq_poll(struct file *file,
1187                             struct poll_table_struct *wait)
1188 {
1189         struct linereq *lr = file->private_data;
1190         __poll_t events = 0;
1191
1192         poll_wait(file, &lr->wait, wait);
1193
1194         if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events,
1195                                                  &lr->wait.lock))
1196                 events = EPOLLIN | EPOLLRDNORM;
1197
1198         return events;
1199 }
1200
1201 static ssize_t linereq_read(struct file *file,
1202                             char __user *buf,
1203                             size_t count,
1204                             loff_t *f_ps)
1205 {
1206         struct linereq *lr = file->private_data;
1207         struct gpio_v2_line_event le;
1208         ssize_t bytes_read = 0;
1209         int ret;
1210
1211         if (count < sizeof(le))
1212                 return -EINVAL;
1213
1214         do {
1215                 spin_lock(&lr->wait.lock);
1216                 if (kfifo_is_empty(&lr->events)) {
1217                         if (bytes_read) {
1218                                 spin_unlock(&lr->wait.lock);
1219                                 return bytes_read;
1220                         }
1221
1222                         if (file->f_flags & O_NONBLOCK) {
1223                                 spin_unlock(&lr->wait.lock);
1224                                 return -EAGAIN;
1225                         }
1226
1227                         ret = wait_event_interruptible_locked(lr->wait,
1228                                         !kfifo_is_empty(&lr->events));
1229                         if (ret) {
1230                                 spin_unlock(&lr->wait.lock);
1231                                 return ret;
1232                         }
1233                 }
1234
1235                 ret = kfifo_out(&lr->events, &le, 1);
1236                 spin_unlock(&lr->wait.lock);
1237                 if (ret != 1) {
1238                         /*
1239                          * This should never happen - we were holding the
1240                          * lock from the moment we learned the fifo is no
1241                          * longer empty until now.
1242                          */
1243                         ret = -EIO;
1244                         break;
1245                 }
1246
1247                 if (copy_to_user(buf + bytes_read, &le, sizeof(le)))
1248                         return -EFAULT;
1249                 bytes_read += sizeof(le);
1250         } while (count >= bytes_read + sizeof(le));
1251
1252         return bytes_read;
1253 }
1254
1255 static void linereq_free(struct linereq *lr)
1256 {
1257         unsigned int i;
1258
1259         for (i = 0; i < lr->num_lines; i++) {
1260                 edge_detector_stop(&lr->lines[i]);
1261                 if (lr->lines[i].desc)
1262                         gpiod_free(lr->lines[i].desc);
1263         }
1264         kfifo_free(&lr->events);
1265         kfree(lr->label);
1266         put_device(&lr->gdev->dev);
1267         kfree(lr);
1268 }
1269
1270 static int linereq_release(struct inode *inode, struct file *file)
1271 {
1272         struct linereq *lr = file->private_data;
1273
1274         linereq_free(lr);
1275         return 0;
1276 }
1277
1278 static const struct file_operations line_fileops = {
1279         .release = linereq_release,
1280         .read = linereq_read,
1281         .poll = linereq_poll,
1282         .owner = THIS_MODULE,
1283         .llseek = noop_llseek,
1284         .unlocked_ioctl = linereq_ioctl,
1285 #ifdef CONFIG_COMPAT
1286         .compat_ioctl = linereq_ioctl_compat,
1287 #endif
1288 };
1289
1290 static int linereq_create(struct gpio_device *gdev, void __user *ip)
1291 {
1292         struct gpio_v2_line_request ulr;
1293         struct gpio_v2_line_config *lc;
1294         struct linereq *lr;
1295         struct file *file;
1296         u64 flags;
1297         unsigned int i;
1298         int fd, ret;
1299
1300         if (copy_from_user(&ulr, ip, sizeof(ulr)))
1301                 return -EFAULT;
1302
1303         if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
1304                 return -EINVAL;
1305
1306         if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding)))
1307                 return -EINVAL;
1308
1309         lc = &ulr.config;
1310         ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
1311         if (ret)
1312                 return ret;
1313
1314         lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
1315         if (!lr)
1316                 return -ENOMEM;
1317
1318         lr->gdev = gdev;
1319         get_device(&gdev->dev);
1320
1321         for (i = 0; i < ulr.num_lines; i++) {
1322                 lr->lines[i].req = lr;
1323                 WRITE_ONCE(lr->lines[i].sw_debounced, 0);
1324                 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
1325         }
1326
1327         if (ulr.consumer[0] != '\0') {
1328                 /* label is only initialized if consumer is set */
1329                 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
1330                                      GFP_KERNEL);
1331                 if (!lr->label) {
1332                         ret = -ENOMEM;
1333                         goto out_free_linereq;
1334                 }
1335         }
1336
1337         mutex_init(&lr->config_mutex);
1338         init_waitqueue_head(&lr->wait);
1339         lr->event_buffer_size = ulr.event_buffer_size;
1340         if (lr->event_buffer_size == 0)
1341                 lr->event_buffer_size = ulr.num_lines * 16;
1342         else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16)
1343                 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;
1344
1345         atomic_set(&lr->seqno, 0);
1346         lr->num_lines = ulr.num_lines;
1347
1348         /* Request each GPIO */
1349         for (i = 0; i < ulr.num_lines; i++) {
1350                 u32 offset = ulr.offsets[i];
1351                 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
1352
1353                 if (IS_ERR(desc)) {
1354                         ret = PTR_ERR(desc);
1355                         goto out_free_linereq;
1356                 }
1357
1358                 ret = gpiod_request(desc, lr->label);
1359                 if (ret)
1360                         goto out_free_linereq;
1361
1362                 lr->lines[i].desc = desc;
1363                 flags = gpio_v2_line_config_flags(lc, i);
1364                 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1365
1366                 ret = gpiod_set_transitory(desc, false);
1367                 if (ret < 0)
1368                         goto out_free_linereq;
1369
1370                 /*
1371                  * Lines have to be requested explicitly for input
1372                  * or output, else the line will be treated "as is".
1373                  */
1374                 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1375                         int val = gpio_v2_line_config_output_value(lc, i);
1376
1377                         ret = gpiod_direction_output(desc, val);
1378                         if (ret)
1379                                 goto out_free_linereq;
1380                 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1381                         ret = gpiod_direction_input(desc);
1382                         if (ret)
1383                                 goto out_free_linereq;
1384
1385                         ret = edge_detector_setup(&lr->lines[i], lc, i,
1386                                         flags & GPIO_V2_LINE_EDGE_FLAGS);
1387                         if (ret)
1388                                 goto out_free_linereq;
1389                 }
1390
1391                 blocking_notifier_call_chain(&desc->gdev->notifier,
1392                                              GPIO_V2_LINE_CHANGED_REQUESTED, desc);
1393
1394                 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
1395                         offset);
1396         }
1397
1398         fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
1399         if (fd < 0) {
1400                 ret = fd;
1401                 goto out_free_linereq;
1402         }
1403
1404         file = anon_inode_getfile("gpio-line", &line_fileops, lr,
1405                                   O_RDONLY | O_CLOEXEC);
1406         if (IS_ERR(file)) {
1407                 ret = PTR_ERR(file);
1408                 goto out_put_unused_fd;
1409         }
1410
1411         ulr.fd = fd;
1412         if (copy_to_user(ip, &ulr, sizeof(ulr))) {
1413                 /*
1414                  * fput() will trigger the release() callback, so do not go onto
1415                  * the regular error cleanup path here.
1416                  */
1417                 fput(file);
1418                 put_unused_fd(fd);
1419                 return -EFAULT;
1420         }
1421
1422         fd_install(fd, file);
1423
1424         dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
1425                 lr->num_lines);
1426
1427         return 0;
1428
1429 out_put_unused_fd:
1430         put_unused_fd(fd);
1431 out_free_linereq:
1432         linereq_free(lr);
1433         return ret;
1434 }
1435
1436 #ifdef CONFIG_GPIO_CDEV_V1
1437
1438 /*
1439  * GPIO line event management
1440  */
1441
1442 /**
1443  * struct lineevent_state - contains the state of a userspace event
1444  * @gdev: the GPIO device the event pertains to
1445  * @label: consumer label used to tag descriptors
1446  * @desc: the GPIO descriptor held by this event
1447  * @eflags: the event flags this line was requested with
1448  * @irq: the interrupt that trigger in response to events on this GPIO
1449  * @wait: wait queue that handles blocking reads of events
1450  * @events: KFIFO for the GPIO events
1451  * @timestamp: cache for the timestamp storing it between hardirq
1452  * and IRQ thread, used to bring the timestamp close to the actual
1453  * event
1454  */
1455 struct lineevent_state {
1456         struct gpio_device *gdev;
1457         const char *label;
1458         struct gpio_desc *desc;
1459         u32 eflags;
1460         int irq;
1461         wait_queue_head_t wait;
1462         DECLARE_KFIFO(events, struct gpioevent_data, 16);
1463         u64 timestamp;
1464 };
1465
1466 #define GPIOEVENT_REQUEST_VALID_FLAGS \
1467         (GPIOEVENT_REQUEST_RISING_EDGE | \
1468         GPIOEVENT_REQUEST_FALLING_EDGE)
1469
1470 static __poll_t lineevent_poll(struct file *file,
1471                                struct poll_table_struct *wait)
1472 {
1473         struct lineevent_state *le = file->private_data;
1474         __poll_t events = 0;
1475
1476         poll_wait(file, &le->wait, wait);
1477
1478         if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
1479                 events = EPOLLIN | EPOLLRDNORM;
1480
1481         return events;
1482 }
1483
1484 static ssize_t lineevent_get_size(void)
1485 {
1486 #if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
1487         /* i386 has no padding after 'id' */
1488         if (in_ia32_syscall()) {
1489                 struct compat_gpioeevent_data {
1490                         compat_u64      timestamp;
1491                         u32             id;
1492                 };
1493
1494                 return sizeof(struct compat_gpioeevent_data);
1495         }
1496 #endif
1497         return sizeof(struct gpioevent_data);
1498 }
1499
1500 static ssize_t lineevent_read(struct file *file,
1501                               char __user *buf,
1502                               size_t count,
1503                               loff_t *f_ps)
1504 {
1505         struct lineevent_state *le = file->private_data;
1506         struct gpioevent_data ge;
1507         ssize_t bytes_read = 0;
1508         ssize_t ge_size;
1509         int ret;
1510
1511         /*
1512          * When compatible system call is being used the struct gpioevent_data,
1513          * in case of at least ia32, has different size due to the alignment
1514          * differences. Because we have first member 64 bits followed by one of
1515          * 32 bits there is no gap between them. The only difference is the
1516          * padding at the end of the data structure. Hence, we calculate the
1517          * actual sizeof() and pass this as an argument to copy_to_user() to
1518          * drop unneeded bytes from the output.
1519          */
1520         ge_size = lineevent_get_size();
1521         if (count < ge_size)
1522                 return -EINVAL;
1523
1524         do {
1525                 spin_lock(&le->wait.lock);
1526                 if (kfifo_is_empty(&le->events)) {
1527                         if (bytes_read) {
1528                                 spin_unlock(&le->wait.lock);
1529                                 return bytes_read;
1530                         }
1531
1532                         if (file->f_flags & O_NONBLOCK) {
1533                                 spin_unlock(&le->wait.lock);
1534                                 return -EAGAIN;
1535                         }
1536
1537                         ret = wait_event_interruptible_locked(le->wait,
1538                                         !kfifo_is_empty(&le->events));
1539                         if (ret) {
1540                                 spin_unlock(&le->wait.lock);
1541                                 return ret;
1542                         }
1543                 }
1544
1545                 ret = kfifo_out(&le->events, &ge, 1);
1546                 spin_unlock(&le->wait.lock);
1547                 if (ret != 1) {
1548                         /*
1549                          * This should never happen - we were holding the lock
1550                          * from the moment we learned the fifo is no longer
1551                          * empty until now.
1552                          */
1553                         ret = -EIO;
1554                         break;
1555                 }
1556
1557                 if (copy_to_user(buf + bytes_read, &ge, ge_size))
1558                         return -EFAULT;
1559                 bytes_read += ge_size;
1560         } while (count >= bytes_read + ge_size);
1561
1562         return bytes_read;
1563 }
1564
1565 static void lineevent_free(struct lineevent_state *le)
1566 {
1567         if (le->irq)
1568                 free_irq(le->irq, le);
1569         if (le->desc)
1570                 gpiod_free(le->desc);
1571         kfree(le->label);
1572         put_device(&le->gdev->dev);
1573         kfree(le);
1574 }
1575
1576 static int lineevent_release(struct inode *inode, struct file *file)
1577 {
1578         lineevent_free(file->private_data);
1579         return 0;
1580 }
1581
1582 static long lineevent_ioctl(struct file *file, unsigned int cmd,
1583                             unsigned long arg)
1584 {
1585         struct lineevent_state *le = file->private_data;
1586         void __user *ip = (void __user *)arg;
1587         struct gpiohandle_data ghd;
1588
1589         /*
1590          * We can get the value for an event line but not set it,
1591          * because it is input by definition.
1592          */
1593         if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
1594                 int val;
1595
1596                 memset(&ghd, 0, sizeof(ghd));
1597
1598                 val = gpiod_get_value_cansleep(le->desc);
1599                 if (val < 0)
1600                         return val;
1601                 ghd.values[0] = val;
1602
1603                 if (copy_to_user(ip, &ghd, sizeof(ghd)))
1604                         return -EFAULT;
1605
1606                 return 0;
1607         }
1608         return -EINVAL;
1609 }
1610
1611 #ifdef CONFIG_COMPAT
1612 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd,
1613                                    unsigned long arg)
1614 {
1615         return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1616 }
1617 #endif
1618
1619 static const struct file_operations lineevent_fileops = {
1620         .release = lineevent_release,
1621         .read = lineevent_read,
1622         .poll = lineevent_poll,
1623         .owner = THIS_MODULE,
1624         .llseek = noop_llseek,
1625         .unlocked_ioctl = lineevent_ioctl,
1626 #ifdef CONFIG_COMPAT
1627         .compat_ioctl = lineevent_ioctl_compat,
1628 #endif
1629 };
1630
1631 static irqreturn_t lineevent_irq_thread(int irq, void *p)
1632 {
1633         struct lineevent_state *le = p;
1634         struct gpioevent_data ge;
1635         int ret;
1636
1637         /* Do not leak kernel stack to userspace */
1638         memset(&ge, 0, sizeof(ge));
1639
1640         /*
1641          * We may be running from a nested threaded interrupt in which case
1642          * we didn't get the timestamp from lineevent_irq_handler().
1643          */
1644         if (!le->timestamp)
1645                 ge.timestamp = ktime_get_ns();
1646         else
1647                 ge.timestamp = le->timestamp;
1648
1649         if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
1650             && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
1651                 int level = gpiod_get_value_cansleep(le->desc);
1652
1653                 if (level)
1654                         /* Emit low-to-high event */
1655                         ge.id = GPIOEVENT_EVENT_RISING_EDGE;
1656                 else
1657                         /* Emit high-to-low event */
1658                         ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
1659         } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
1660                 /* Emit low-to-high event */
1661                 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
1662         } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
1663                 /* Emit high-to-low event */
1664                 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
1665         } else {
1666                 return IRQ_NONE;
1667         }
1668
1669         ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
1670                                             1, &le->wait.lock);
1671         if (ret)
1672                 wake_up_poll(&le->wait, EPOLLIN);
1673         else
1674                 pr_debug_ratelimited("event FIFO is full - event dropped\n");
1675
1676         return IRQ_HANDLED;
1677 }
1678
1679 static irqreturn_t lineevent_irq_handler(int irq, void *p)
1680 {
1681         struct lineevent_state *le = p;
1682
1683         /*
1684          * Just store the timestamp in hardirq context so we get it as
1685          * close in time as possible to the actual event.
1686          */
1687         le->timestamp = ktime_get_ns();
1688
1689         return IRQ_WAKE_THREAD;
1690 }
1691
1692 static int lineevent_create(struct gpio_device *gdev, void __user *ip)
1693 {
1694         struct gpioevent_request eventreq;
1695         struct lineevent_state *le;
1696         struct gpio_desc *desc;
1697         struct file *file;
1698         u32 offset;
1699         u32 lflags;
1700         u32 eflags;
1701         int fd;
1702         int ret;
1703         int irq, irqflags = 0;
1704
1705         if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
1706                 return -EFAULT;
1707
1708         offset = eventreq.lineoffset;
1709         lflags = eventreq.handleflags;
1710         eflags = eventreq.eventflags;
1711
1712         desc = gpiochip_get_desc(gdev->chip, offset);
1713         if (IS_ERR(desc))
1714                 return PTR_ERR(desc);
1715
1716         /* Return an error if a unknown flag is set */
1717         if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
1718             (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
1719                 return -EINVAL;
1720
1721         /* This is just wrong: we don't look for events on output lines */
1722         if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
1723             (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
1724             (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
1725                 return -EINVAL;
1726
1727         /* Only one bias flag can be set. */
1728         if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
1729              (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
1730                         GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
1731             ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
1732              (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
1733                 return -EINVAL;
1734
1735         le = kzalloc(sizeof(*le), GFP_KERNEL);
1736         if (!le)
1737                 return -ENOMEM;
1738         le->gdev = gdev;
1739         get_device(&gdev->dev);
1740
1741         if (eventreq.consumer_label[0] != '\0') {
1742                 /* label is only initialized if consumer_label is set */
1743                 le->label = kstrndup(eventreq.consumer_label,
1744                                      sizeof(eventreq.consumer_label) - 1,
1745                                      GFP_KERNEL);
1746                 if (!le->label) {
1747                         ret = -ENOMEM;
1748                         goto out_free_le;
1749                 }
1750         }
1751
1752         ret = gpiod_request(desc, le->label);
1753         if (ret)
1754                 goto out_free_le;
1755         le->desc = desc;
1756         le->eflags = eflags;
1757
1758         linehandle_flags_to_desc_flags(lflags, &desc->flags);
1759
1760         ret = gpiod_direction_input(desc);
1761         if (ret)
1762                 goto out_free_le;
1763
1764         blocking_notifier_call_chain(&desc->gdev->notifier,
1765                                      GPIO_V2_LINE_CHANGED_REQUESTED, desc);
1766
1767         irq = gpiod_to_irq(desc);
1768         if (irq <= 0) {
1769                 ret = -ENODEV;
1770                 goto out_free_le;
1771         }
1772
1773         if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
1774                 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
1775                         IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
1776         if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
1777                 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
1778                         IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
1779         irqflags |= IRQF_ONESHOT;
1780
1781         INIT_KFIFO(le->events);
1782         init_waitqueue_head(&le->wait);
1783
1784         /* Request a thread to read the events */
1785         ret = request_threaded_irq(irq,
1786                                    lineevent_irq_handler,
1787                                    lineevent_irq_thread,
1788                                    irqflags,
1789                                    le->label,
1790                                    le);
1791         if (ret)
1792                 goto out_free_le;
1793
1794         le->irq = irq;
1795
1796         fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
1797         if (fd < 0) {
1798                 ret = fd;
1799                 goto out_free_le;
1800         }
1801
1802         file = anon_inode_getfile("gpio-event",
1803                                   &lineevent_fileops,
1804                                   le,
1805                                   O_RDONLY | O_CLOEXEC);
1806         if (IS_ERR(file)) {
1807                 ret = PTR_ERR(file);
1808                 goto out_put_unused_fd;
1809         }
1810
1811         eventreq.fd = fd;
1812         if (copy_to_user(ip, &eventreq, sizeof(eventreq))) {
1813                 /*
1814                  * fput() will trigger the release() callback, so do not go onto
1815                  * the regular error cleanup path here.
1816                  */
1817                 fput(file);
1818                 put_unused_fd(fd);
1819                 return -EFAULT;
1820         }
1821
1822         fd_install(fd, file);
1823
1824         return 0;
1825
1826 out_put_unused_fd:
1827         put_unused_fd(fd);
1828 out_free_le:
1829         lineevent_free(le);
1830         return ret;
1831 }
1832
1833 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2,
1834                                     struct gpioline_info *info_v1)
1835 {
1836         u64 flagsv2 = info_v2->flags;
1837
1838         memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name));
1839         memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer));
1840         info_v1->line_offset = info_v2->offset;
1841         info_v1->flags = 0;
1842
1843         if (flagsv2 & GPIO_V2_LINE_FLAG_USED)
1844                 info_v1->flags |= GPIOLINE_FLAG_KERNEL;
1845
1846         if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT)
1847                 info_v1->flags |= GPIOLINE_FLAG_IS_OUT;
1848
1849         if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
1850                 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
1851
1852         if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN)
1853                 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN;
1854         if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE)
1855                 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE;
1856
1857         if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)
1858                 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
1859         if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN)
1860                 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
1861         if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED)
1862                 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
1863 }
1864
1865 static void gpio_v2_line_info_changed_to_v1(
1866                 struct gpio_v2_line_info_changed *lic_v2,
1867                 struct gpioline_info_changed *lic_v1)
1868 {
1869         memset(lic_v1, 0, sizeof(*lic_v1));
1870         gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info);
1871         lic_v1->timestamp = lic_v2->timestamp_ns;
1872         lic_v1->event_type = lic_v2->event_type;
1873 }
1874
1875 #endif /* CONFIG_GPIO_CDEV_V1 */
1876
1877 static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
1878                                   struct gpio_v2_line_info *info)
1879 {
1880         struct gpio_chip *gc = desc->gdev->chip;
1881         bool ok_for_pinctrl;
1882         unsigned long flags;
1883         u32 debounce_period_us;
1884         unsigned int num_attrs = 0;
1885
1886         memset(info, 0, sizeof(*info));
1887         info->offset = gpio_chip_hwgpio(desc);
1888
1889         /*
1890          * This function takes a mutex so we must check this before taking
1891          * the spinlock.
1892          *
1893          * FIXME: find a non-racy way to retrieve this information. Maybe a
1894          * lock common to both frameworks?
1895          */
1896         ok_for_pinctrl =
1897                 pinctrl_gpio_can_use_line(gc->base + info->offset);
1898
1899         spin_lock_irqsave(&gpio_lock, flags);
1900
1901         if (desc->name)
1902                 strscpy(info->name, desc->name, sizeof(info->name));
1903
1904         if (desc->label)
1905                 strscpy(info->consumer, desc->label, sizeof(info->consumer));
1906
1907         /*
1908          * Userspace only need to know that the kernel is using this GPIO so
1909          * it can't use it.
1910          */
1911         info->flags = 0;
1912         if (test_bit(FLAG_REQUESTED, &desc->flags) ||
1913             test_bit(FLAG_IS_HOGGED, &desc->flags) ||
1914             test_bit(FLAG_USED_AS_IRQ, &desc->flags) ||
1915             test_bit(FLAG_EXPORT, &desc->flags) ||
1916             test_bit(FLAG_SYSFS, &desc->flags) ||
1917             !ok_for_pinctrl)
1918                 info->flags |= GPIO_V2_LINE_FLAG_USED;
1919
1920         if (test_bit(FLAG_IS_OUT, &desc->flags))
1921                 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
1922         else
1923                 info->flags |= GPIO_V2_LINE_FLAG_INPUT;
1924
1925         if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1926                 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
1927
1928         if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
1929                 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
1930         if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
1931                 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
1932
1933         if (test_bit(FLAG_BIAS_DISABLE, &desc->flags))
1934                 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
1935         if (test_bit(FLAG_PULL_DOWN, &desc->flags))
1936                 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
1937         if (test_bit(FLAG_PULL_UP, &desc->flags))
1938                 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
1939
1940         if (test_bit(FLAG_EDGE_RISING, &desc->flags))
1941                 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
1942         if (test_bit(FLAG_EDGE_FALLING, &desc->flags))
1943                 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
1944
1945         debounce_period_us = READ_ONCE(desc->debounce_period_us);
1946         if (debounce_period_us) {
1947                 info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
1948                 info->attrs[num_attrs].debounce_period_us = debounce_period_us;
1949                 num_attrs++;
1950         }
1951         info->num_attrs = num_attrs;
1952
1953         spin_unlock_irqrestore(&gpio_lock, flags);
1954 }
1955
1956 struct gpio_chardev_data {
1957         struct gpio_device *gdev;
1958         wait_queue_head_t wait;
1959         DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32);
1960         struct notifier_block lineinfo_changed_nb;
1961         unsigned long *watched_lines;
1962 #ifdef CONFIG_GPIO_CDEV_V1
1963         atomic_t watch_abi_version;
1964 #endif
1965 };
1966
1967 static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip)
1968 {
1969         struct gpio_device *gdev = cdev->gdev;
1970         struct gpiochip_info chipinfo;
1971
1972         memset(&chipinfo, 0, sizeof(chipinfo));
1973
1974         strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name));
1975         strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label));
1976         chipinfo.lines = gdev->ngpio;
1977         if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
1978                 return -EFAULT;
1979         return 0;
1980 }
1981
1982 #ifdef CONFIG_GPIO_CDEV_V1
1983 /*
1984  * returns 0 if the versions match, else the previously selected ABI version
1985  */
1986 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata,
1987                                        unsigned int version)
1988 {
1989         int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version);
1990
1991         if (abiv == version)
1992                 return 0;
1993
1994         return abiv;
1995 }
1996
1997 static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
1998                            bool watch)
1999 {
2000         struct gpio_desc *desc;
2001         struct gpioline_info lineinfo;
2002         struct gpio_v2_line_info lineinfo_v2;
2003
2004         if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2005                 return -EFAULT;
2006
2007         /* this doubles as a range check on line_offset */
2008         desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset);
2009         if (IS_ERR(desc))
2010                 return PTR_ERR(desc);
2011
2012         if (watch) {
2013                 if (lineinfo_ensure_abi_version(cdev, 1))
2014                         return -EPERM;
2015
2016                 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
2017                         return -EBUSY;
2018         }
2019
2020         gpio_desc_to_lineinfo(desc, &lineinfo_v2);
2021         gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
2022
2023         if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2024                 if (watch)
2025                         clear_bit(lineinfo.line_offset, cdev->watched_lines);
2026                 return -EFAULT;
2027         }
2028
2029         return 0;
2030 }
2031 #endif
2032
2033 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
2034                         bool watch)
2035 {
2036         struct gpio_desc *desc;
2037         struct gpio_v2_line_info lineinfo;
2038
2039         if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2040                 return -EFAULT;
2041
2042         if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding)))
2043                 return -EINVAL;
2044
2045         desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset);
2046         if (IS_ERR(desc))
2047                 return PTR_ERR(desc);
2048
2049         if (watch) {
2050 #ifdef CONFIG_GPIO_CDEV_V1
2051                 if (lineinfo_ensure_abi_version(cdev, 2))
2052                         return -EPERM;
2053 #endif
2054                 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
2055                         return -EBUSY;
2056         }
2057         gpio_desc_to_lineinfo(desc, &lineinfo);
2058
2059         if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2060                 if (watch)
2061                         clear_bit(lineinfo.offset, cdev->watched_lines);
2062                 return -EFAULT;
2063         }
2064
2065         return 0;
2066 }
2067
2068 static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip)
2069 {
2070         __u32 offset;
2071
2072         if (copy_from_user(&offset, ip, sizeof(offset)))
2073                 return -EFAULT;
2074
2075         if (offset >= cdev->gdev->ngpio)
2076                 return -EINVAL;
2077
2078         if (!test_and_clear_bit(offset, cdev->watched_lines))
2079                 return -EBUSY;
2080
2081         return 0;
2082 }
2083
2084 /*
2085  * gpio_ioctl() - ioctl handler for the GPIO chardev
2086  */
2087 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2088 {
2089         struct gpio_chardev_data *cdev = file->private_data;
2090         struct gpio_device *gdev = cdev->gdev;
2091         void __user *ip = (void __user *)arg;
2092
2093         /* We fail any subsequent ioctl():s when the chip is gone */
2094         if (!gdev->chip)
2095                 return -ENODEV;
2096
2097         /* Fill in the struct and pass to userspace */
2098         if (cmd == GPIO_GET_CHIPINFO_IOCTL) {
2099                 return chipinfo_get(cdev, ip);
2100 #ifdef CONFIG_GPIO_CDEV_V1
2101         } else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) {
2102                 return linehandle_create(gdev, ip);
2103         } else if (cmd == GPIO_GET_LINEEVENT_IOCTL) {
2104                 return lineevent_create(gdev, ip);
2105         } else if (cmd == GPIO_GET_LINEINFO_IOCTL ||
2106                    cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) {
2107                 return lineinfo_get_v1(cdev, ip,
2108                                        cmd == GPIO_GET_LINEINFO_WATCH_IOCTL);
2109 #endif /* CONFIG_GPIO_CDEV_V1 */
2110         } else if (cmd == GPIO_V2_GET_LINEINFO_IOCTL ||
2111                    cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL) {
2112                 return lineinfo_get(cdev, ip,
2113                                     cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL);
2114         } else if (cmd == GPIO_V2_GET_LINE_IOCTL) {
2115                 return linereq_create(gdev, ip);
2116         } else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) {
2117                 return lineinfo_unwatch(cdev, ip);
2118         }
2119         return -EINVAL;
2120 }
2121
2122 #ifdef CONFIG_COMPAT
2123 static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
2124                               unsigned long arg)
2125 {
2126         return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2127 }
2128 #endif
2129
2130 static struct gpio_chardev_data *
2131 to_gpio_chardev_data(struct notifier_block *nb)
2132 {
2133         return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
2134 }
2135
2136 static int lineinfo_changed_notify(struct notifier_block *nb,
2137                                    unsigned long action, void *data)
2138 {
2139         struct gpio_chardev_data *cdev = to_gpio_chardev_data(nb);
2140         struct gpio_v2_line_info_changed chg;
2141         struct gpio_desc *desc = data;
2142         int ret;
2143
2144         if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines))
2145                 return NOTIFY_DONE;
2146
2147         memset(&chg, 0, sizeof(chg));
2148         chg.event_type = action;
2149         chg.timestamp_ns = ktime_get_ns();
2150         gpio_desc_to_lineinfo(desc, &chg.info);
2151
2152         ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
2153         if (ret)
2154                 wake_up_poll(&cdev->wait, EPOLLIN);
2155         else
2156                 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");
2157
2158         return NOTIFY_OK;
2159 }
2160
2161 static __poll_t lineinfo_watch_poll(struct file *file,
2162                                     struct poll_table_struct *pollt)
2163 {
2164         struct gpio_chardev_data *cdev = file->private_data;
2165         __poll_t events = 0;
2166
2167         poll_wait(file, &cdev->wait, pollt);
2168
2169         if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events,
2170                                                  &cdev->wait.lock))
2171                 events = EPOLLIN | EPOLLRDNORM;
2172
2173         return events;
2174 }
2175
2176 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
2177                                    size_t count, loff_t *off)
2178 {
2179         struct gpio_chardev_data *cdev = file->private_data;
2180         struct gpio_v2_line_info_changed event;
2181         ssize_t bytes_read = 0;
2182         int ret;
2183         size_t event_size;
2184
2185 #ifndef CONFIG_GPIO_CDEV_V1
2186         event_size = sizeof(struct gpio_v2_line_info_changed);
2187         if (count < event_size)
2188                 return -EINVAL;
2189 #endif
2190
2191         do {
2192                 spin_lock(&cdev->wait.lock);
2193                 if (kfifo_is_empty(&cdev->events)) {
2194                         if (bytes_read) {
2195                                 spin_unlock(&cdev->wait.lock);
2196                                 return bytes_read;
2197                         }
2198
2199                         if (file->f_flags & O_NONBLOCK) {
2200                                 spin_unlock(&cdev->wait.lock);
2201                                 return -EAGAIN;
2202                         }
2203
2204                         ret = wait_event_interruptible_locked(cdev->wait,
2205                                         !kfifo_is_empty(&cdev->events));
2206                         if (ret) {
2207                                 spin_unlock(&cdev->wait.lock);
2208                                 return ret;
2209                         }
2210                 }
2211 #ifdef CONFIG_GPIO_CDEV_V1
2212                 /* must be after kfifo check so watch_abi_version is set */
2213                 if (atomic_read(&cdev->watch_abi_version) == 2)
2214                         event_size = sizeof(struct gpio_v2_line_info_changed);
2215                 else
2216                         event_size = sizeof(struct gpioline_info_changed);
2217                 if (count < event_size) {
2218                         spin_unlock(&cdev->wait.lock);
2219                         return -EINVAL;
2220                 }
2221 #endif
2222                 ret = kfifo_out(&cdev->events, &event, 1);
2223                 spin_unlock(&cdev->wait.lock);
2224                 if (ret != 1) {
2225                         ret = -EIO;
2226                         break;
2227                         /* We should never get here. See lineevent_read(). */
2228                 }
2229
2230 #ifdef CONFIG_GPIO_CDEV_V1
2231                 if (event_size == sizeof(struct gpio_v2_line_info_changed)) {
2232                         if (copy_to_user(buf + bytes_read, &event, event_size))
2233                                 return -EFAULT;
2234                 } else {
2235                         struct gpioline_info_changed event_v1;
2236
2237                         gpio_v2_line_info_changed_to_v1(&event, &event_v1);
2238                         if (copy_to_user(buf + bytes_read, &event_v1,
2239                                          event_size))
2240                                 return -EFAULT;
2241                 }
2242 #else
2243                 if (copy_to_user(buf + bytes_read, &event, event_size))
2244                         return -EFAULT;
2245 #endif
2246                 bytes_read += event_size;
2247         } while (count >= bytes_read + sizeof(event));
2248
2249         return bytes_read;
2250 }
2251
2252 /**
2253  * gpio_chrdev_open() - open the chardev for ioctl operations
2254  * @inode: inode for this chardev
2255  * @file: file struct for storing private data
2256  * Returns 0 on success
2257  */
2258 static int gpio_chrdev_open(struct inode *inode, struct file *file)
2259 {
2260         struct gpio_device *gdev = container_of(inode->i_cdev,
2261                                                 struct gpio_device, chrdev);
2262         struct gpio_chardev_data *cdev;
2263         int ret = -ENOMEM;
2264
2265         /* Fail on open if the backing gpiochip is gone */
2266         if (!gdev->chip)
2267                 return -ENODEV;
2268
2269         cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
2270         if (!cdev)
2271                 return -ENOMEM;
2272
2273         cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL);
2274         if (!cdev->watched_lines)
2275                 goto out_free_cdev;
2276
2277         init_waitqueue_head(&cdev->wait);
2278         INIT_KFIFO(cdev->events);
2279         cdev->gdev = gdev;
2280
2281         cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
2282         ret = blocking_notifier_chain_register(&gdev->notifier,
2283                                                &cdev->lineinfo_changed_nb);
2284         if (ret)
2285                 goto out_free_bitmap;
2286
2287         get_device(&gdev->dev);
2288         file->private_data = cdev;
2289
2290         ret = nonseekable_open(inode, file);
2291         if (ret)
2292                 goto out_unregister_notifier;
2293
2294         return ret;
2295
2296 out_unregister_notifier:
2297         blocking_notifier_chain_unregister(&gdev->notifier,
2298                                            &cdev->lineinfo_changed_nb);
2299 out_free_bitmap:
2300         bitmap_free(cdev->watched_lines);
2301 out_free_cdev:
2302         kfree(cdev);
2303         return ret;
2304 }
2305
2306 /**
2307  * gpio_chrdev_release() - close chardev after ioctl operations
2308  * @inode: inode for this chardev
2309  * @file: file struct for storing private data
2310  * Returns 0 on success
2311  */
2312 static int gpio_chrdev_release(struct inode *inode, struct file *file)
2313 {
2314         struct gpio_chardev_data *cdev = file->private_data;
2315         struct gpio_device *gdev = cdev->gdev;
2316
2317         bitmap_free(cdev->watched_lines);
2318         blocking_notifier_chain_unregister(&gdev->notifier,
2319                                            &cdev->lineinfo_changed_nb);
2320         put_device(&gdev->dev);
2321         kfree(cdev);
2322
2323         return 0;
2324 }
2325
2326 static const struct file_operations gpio_fileops = {
2327         .release = gpio_chrdev_release,
2328         .open = gpio_chrdev_open,
2329         .poll = lineinfo_watch_poll,
2330         .read = lineinfo_watch_read,
2331         .owner = THIS_MODULE,
2332         .llseek = no_llseek,
2333         .unlocked_ioctl = gpio_ioctl,
2334 #ifdef CONFIG_COMPAT
2335         .compat_ioctl = gpio_ioctl_compat,
2336 #endif
2337 };
2338
2339 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
2340 {
2341         int ret;
2342
2343         cdev_init(&gdev->chrdev, &gpio_fileops);
2344         gdev->chrdev.owner = THIS_MODULE;
2345         gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
2346
2347         ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
2348         if (ret)
2349                 return ret;
2350
2351         chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
2352                  MAJOR(devt), gdev->id);
2353
2354         return 0;
2355 }
2356
2357 void gpiolib_cdev_unregister(struct gpio_device *gdev)
2358 {
2359         cdev_device_del(&gdev->chrdev, &gdev->dev);
2360 }