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_FLAG_EVENT_CLOCK_REALTIME | \ 513 GPIO_V2_LINE_BIAS_FLAGS) 514 515 static void linereq_put_event(struct linereq *lr, 516 struct gpio_v2_line_event *le) 517 { 518 bool overflow = false; 519 520 spin_lock(&lr->wait.lock); 521 if (kfifo_is_full(&lr->events)) { 522 overflow = true; 523 kfifo_skip(&lr->events); 524 } 525 kfifo_in(&lr->events, le, 1); 526 spin_unlock(&lr->wait.lock); 527 if (!overflow) 528 wake_up_poll(&lr->wait, EPOLLIN); 529 else 530 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 531 } 532 533 static u64 line_event_timestamp(struct line *line) 534 { 535 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags)) 536 return ktime_get_real_ns(); 537 538 return ktime_get_ns(); 539 } 540 541 static irqreturn_t edge_irq_thread(int irq, void *p) 542 { 543 struct line *line = p; 544 struct linereq *lr = line->req; 545 struct gpio_v2_line_event le; 546 547 /* Do not leak kernel stack to userspace */ 548 memset(&le, 0, sizeof(le)); 549 550 if (line->timestamp_ns) { 551 le.timestamp_ns = line->timestamp_ns; 552 } else { 553 /* 554 * We may be running from a nested threaded interrupt in 555 * which case we didn't get the timestamp from 556 * edge_irq_handler(). 557 */ 558 le.timestamp_ns = line_event_timestamp(line); 559 if (lr->num_lines != 1) 560 line->req_seqno = atomic_inc_return(&lr->seqno); 561 } 562 line->timestamp_ns = 0; 563 564 if (line->eflags == (GPIO_V2_LINE_FLAG_EDGE_RISING | 565 GPIO_V2_LINE_FLAG_EDGE_FALLING)) { 566 int level = gpiod_get_value_cansleep(line->desc); 567 568 if (level) 569 /* Emit low-to-high event */ 570 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 571 else 572 /* Emit high-to-low event */ 573 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 574 } else if (line->eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) { 575 /* Emit low-to-high event */ 576 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 577 } else if (line->eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) { 578 /* Emit high-to-low event */ 579 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 580 } else { 581 return IRQ_NONE; 582 } 583 line->line_seqno++; 584 le.line_seqno = line->line_seqno; 585 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno; 586 le.offset = gpio_chip_hwgpio(line->desc); 587 588 linereq_put_event(lr, &le); 589 590 return IRQ_HANDLED; 591 } 592 593 static irqreturn_t edge_irq_handler(int irq, void *p) 594 { 595 struct line *line = p; 596 struct linereq *lr = line->req; 597 598 /* 599 * Just store the timestamp in hardirq context so we get it as 600 * close in time as possible to the actual event. 601 */ 602 line->timestamp_ns = line_event_timestamp(line); 603 604 if (lr->num_lines != 1) 605 line->req_seqno = atomic_inc_return(&lr->seqno); 606 607 return IRQ_WAKE_THREAD; 608 } 609 610 /* 611 * returns the current debounced logical value. 612 */ 613 static bool debounced_value(struct line *line) 614 { 615 bool value; 616 617 /* 618 * minor race - debouncer may be stopped here, so edge_detector_stop() 619 * must leave the value unchanged so the following will read the level 620 * from when the debouncer was last running. 621 */ 622 value = READ_ONCE(line->level); 623 624 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags)) 625 value = !value; 626 627 return value; 628 } 629 630 static irqreturn_t debounce_irq_handler(int irq, void *p) 631 { 632 struct line *line = p; 633 634 mod_delayed_work(system_wq, &line->work, 635 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); 636 637 return IRQ_HANDLED; 638 } 639 640 static void debounce_work_func(struct work_struct *work) 641 { 642 struct gpio_v2_line_event le; 643 struct line *line = container_of(work, struct line, work.work); 644 struct linereq *lr; 645 int level; 646 647 level = gpiod_get_raw_value_cansleep(line->desc); 648 if (level < 0) { 649 pr_debug_ratelimited("debouncer failed to read line value\n"); 650 return; 651 } 652 653 if (READ_ONCE(line->level) == level) 654 return; 655 656 WRITE_ONCE(line->level, level); 657 658 /* -- edge detection -- */ 659 if (!line->eflags) 660 return; 661 662 /* switch from physical level to logical - if they differ */ 663 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags)) 664 level = !level; 665 666 /* ignore edges that are not being monitored */ 667 if (((line->eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) || 668 ((line->eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level)) 669 return; 670 671 /* Do not leak kernel stack to userspace */ 672 memset(&le, 0, sizeof(le)); 673 674 lr = line->req; 675 le.timestamp_ns = line_event_timestamp(line); 676 le.offset = gpio_chip_hwgpio(line->desc); 677 line->line_seqno++; 678 le.line_seqno = line->line_seqno; 679 le.seqno = (lr->num_lines == 1) ? 680 le.line_seqno : atomic_inc_return(&lr->seqno); 681 682 if (level) 683 /* Emit low-to-high event */ 684 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 685 else 686 /* Emit high-to-low event */ 687 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 688 689 linereq_put_event(lr, &le); 690 } 691 692 static int debounce_setup(struct line *line, 693 unsigned int debounce_period_us) 694 { 695 unsigned long irqflags; 696 int ret, level, irq; 697 698 /* try hardware */ 699 ret = gpiod_set_debounce(line->desc, debounce_period_us); 700 if (!ret) { 701 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 702 return ret; 703 } 704 if (ret != -ENOTSUPP) 705 return ret; 706 707 if (debounce_period_us) { 708 /* setup software debounce */ 709 level = gpiod_get_raw_value_cansleep(line->desc); 710 if (level < 0) 711 return level; 712 713 irq = gpiod_to_irq(line->desc); 714 if (irq < 0) 715 return -ENXIO; 716 717 WRITE_ONCE(line->level, level); 718 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING; 719 ret = request_irq(irq, debounce_irq_handler, irqflags, 720 line->req->label, line); 721 if (ret) 722 return ret; 723 724 WRITE_ONCE(line->sw_debounced, 1); 725 line->irq = irq; 726 } 727 return 0; 728 } 729 730 static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc, 731 unsigned int line_idx) 732 { 733 unsigned int i; 734 u64 mask = BIT_ULL(line_idx); 735 736 for (i = 0; i < lc->num_attrs; i++) { 737 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 738 (lc->attrs[i].mask & mask)) 739 return true; 740 } 741 return false; 742 } 743 744 static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc, 745 unsigned int line_idx) 746 { 747 unsigned int i; 748 u64 mask = BIT_ULL(line_idx); 749 750 for (i = 0; i < lc->num_attrs; i++) { 751 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 752 (lc->attrs[i].mask & mask)) 753 return lc->attrs[i].attr.debounce_period_us; 754 } 755 return 0; 756 } 757 758 static void edge_detector_stop(struct line *line) 759 { 760 if (line->irq) { 761 free_irq(line->irq, line); 762 line->irq = 0; 763 } 764 765 cancel_delayed_work_sync(&line->work); 766 WRITE_ONCE(line->sw_debounced, 0); 767 line->eflags = 0; 768 /* do not change line->level - see comment in debounced_value() */ 769 } 770 771 static int edge_detector_setup(struct line *line, 772 struct gpio_v2_line_config *lc, 773 unsigned int line_idx, 774 u64 eflags) 775 { 776 u32 debounce_period_us; 777 unsigned long irqflags = 0; 778 int irq, ret; 779 780 if (eflags && !kfifo_initialized(&line->req->events)) { 781 ret = kfifo_alloc(&line->req->events, 782 line->req->event_buffer_size, GFP_KERNEL); 783 if (ret) 784 return ret; 785 } 786 line->eflags = eflags; 787 if (gpio_v2_line_config_debounced(lc, line_idx)) { 788 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx); 789 ret = debounce_setup(line, debounce_period_us); 790 if (ret) 791 return ret; 792 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 793 } 794 795 /* detection disabled or sw debouncer will provide edge detection */ 796 if (!eflags || READ_ONCE(line->sw_debounced)) 797 return 0; 798 799 irq = gpiod_to_irq(line->desc); 800 if (irq < 0) 801 return -ENXIO; 802 803 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING) 804 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 805 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 806 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING) 807 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 808 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 809 irqflags |= IRQF_ONESHOT; 810 811 /* Request a thread to read the events */ 812 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread, 813 irqflags, line->req->label, line); 814 if (ret) 815 return ret; 816 817 line->irq = irq; 818 return 0; 819 } 820 821 static int edge_detector_update(struct line *line, 822 struct gpio_v2_line_config *lc, 823 unsigned int line_idx, 824 u64 eflags, bool polarity_change) 825 { 826 unsigned int debounce_period_us = 827 gpio_v2_line_config_debounce_period(lc, line_idx); 828 829 if ((line->eflags == eflags) && !polarity_change && 830 (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us)) 831 return 0; 832 833 /* sw debounced and still will be...*/ 834 if (debounce_period_us && READ_ONCE(line->sw_debounced)) { 835 line->eflags = eflags; 836 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 837 return 0; 838 } 839 840 /* reconfiguring edge detection or sw debounce being disabled */ 841 if ((line->irq && !READ_ONCE(line->sw_debounced)) || 842 (!debounce_period_us && READ_ONCE(line->sw_debounced))) 843 edge_detector_stop(line); 844 845 return edge_detector_setup(line, lc, line_idx, eflags); 846 } 847 848 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc, 849 unsigned int line_idx) 850 { 851 unsigned int i; 852 u64 mask = BIT_ULL(line_idx); 853 854 for (i = 0; i < lc->num_attrs; i++) { 855 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) && 856 (lc->attrs[i].mask & mask)) 857 return lc->attrs[i].attr.flags; 858 } 859 return lc->flags; 860 } 861 862 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc, 863 unsigned int line_idx) 864 { 865 unsigned int i; 866 u64 mask = BIT_ULL(line_idx); 867 868 for (i = 0; i < lc->num_attrs; i++) { 869 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) && 870 (lc->attrs[i].mask & mask)) 871 return !!(lc->attrs[i].attr.values & mask); 872 } 873 return 0; 874 } 875 876 static int gpio_v2_line_flags_validate(u64 flags) 877 { 878 /* Return an error if an unknown flag is set */ 879 if (flags & ~GPIO_V2_LINE_VALID_FLAGS) 880 return -EINVAL; 881 882 /* 883 * Do not allow both INPUT and OUTPUT flags to be set as they are 884 * contradictory. 885 */ 886 if ((flags & GPIO_V2_LINE_FLAG_INPUT) && 887 (flags & GPIO_V2_LINE_FLAG_OUTPUT)) 888 return -EINVAL; 889 890 /* Edge detection requires explicit input. */ 891 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) && 892 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 893 return -EINVAL; 894 895 /* 896 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single 897 * request. If the hardware actually supports enabling both at the 898 * same time the electrical result would be disastrous. 899 */ 900 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) && 901 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE)) 902 return -EINVAL; 903 904 /* Drive requires explicit output direction. */ 905 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) && 906 !(flags & GPIO_V2_LINE_FLAG_OUTPUT)) 907 return -EINVAL; 908 909 /* Bias requires explicit direction. */ 910 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) && 911 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS)) 912 return -EINVAL; 913 914 /* Only one bias flag can be set. */ 915 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) && 916 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | 917 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) || 918 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) && 919 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) 920 return -EINVAL; 921 922 return 0; 923 } 924 925 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc, 926 unsigned int num_lines) 927 { 928 unsigned int i; 929 u64 flags; 930 int ret; 931 932 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX) 933 return -EINVAL; 934 935 if (memchr_inv(lc->padding, 0, sizeof(lc->padding))) 936 return -EINVAL; 937 938 for (i = 0; i < num_lines; i++) { 939 flags = gpio_v2_line_config_flags(lc, i); 940 ret = gpio_v2_line_flags_validate(flags); 941 if (ret) 942 return ret; 943 944 /* debounce requires explicit input */ 945 if (gpio_v2_line_config_debounced(lc, i) && 946 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 947 return -EINVAL; 948 } 949 return 0; 950 } 951 952 static void gpio_v2_line_config_flags_to_desc_flags(u64 flags, 953 unsigned long *flagsp) 954 { 955 assign_bit(FLAG_ACTIVE_LOW, flagsp, 956 flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW); 957 958 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) 959 set_bit(FLAG_IS_OUT, flagsp); 960 else if (flags & GPIO_V2_LINE_FLAG_INPUT) 961 clear_bit(FLAG_IS_OUT, flagsp); 962 963 assign_bit(FLAG_EDGE_RISING, flagsp, 964 flags & GPIO_V2_LINE_FLAG_EDGE_RISING); 965 assign_bit(FLAG_EDGE_FALLING, flagsp, 966 flags & GPIO_V2_LINE_FLAG_EDGE_FALLING); 967 968 assign_bit(FLAG_OPEN_DRAIN, flagsp, 969 flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN); 970 assign_bit(FLAG_OPEN_SOURCE, flagsp, 971 flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE); 972 973 assign_bit(FLAG_PULL_UP, flagsp, 974 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP); 975 assign_bit(FLAG_PULL_DOWN, flagsp, 976 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN); 977 assign_bit(FLAG_BIAS_DISABLE, flagsp, 978 flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED); 979 980 assign_bit(FLAG_EVENT_CLOCK_REALTIME, flagsp, 981 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME); 982 } 983 984 static long linereq_get_values(struct linereq *lr, void __user *ip) 985 { 986 struct gpio_v2_line_values lv; 987 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 988 struct gpio_desc **descs; 989 unsigned int i, didx, num_get; 990 bool val; 991 int ret; 992 993 /* NOTE: It's ok to read values of output lines. */ 994 if (copy_from_user(&lv, ip, sizeof(lv))) 995 return -EFAULT; 996 997 for (num_get = 0, i = 0; i < lr->num_lines; i++) { 998 if (lv.mask & BIT_ULL(i)) { 999 num_get++; 1000 descs = &lr->lines[i].desc; 1001 } 1002 } 1003 1004 if (num_get == 0) 1005 return -EINVAL; 1006 1007 if (num_get != 1) { 1008 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL); 1009 if (!descs) 1010 return -ENOMEM; 1011 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1012 if (lv.mask & BIT_ULL(i)) { 1013 descs[didx] = lr->lines[i].desc; 1014 didx++; 1015 } 1016 } 1017 } 1018 ret = gpiod_get_array_value_complex(false, true, num_get, 1019 descs, NULL, vals); 1020 1021 if (num_get != 1) 1022 kfree(descs); 1023 if (ret) 1024 return ret; 1025 1026 lv.bits = 0; 1027 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1028 if (lv.mask & BIT_ULL(i)) { 1029 if (lr->lines[i].sw_debounced) 1030 val = debounced_value(&lr->lines[i]); 1031 else 1032 val = test_bit(didx, vals); 1033 if (val) 1034 lv.bits |= BIT_ULL(i); 1035 didx++; 1036 } 1037 } 1038 1039 if (copy_to_user(ip, &lv, sizeof(lv))) 1040 return -EFAULT; 1041 1042 return 0; 1043 } 1044 1045 static long linereq_set_values_unlocked(struct linereq *lr, 1046 struct gpio_v2_line_values *lv) 1047 { 1048 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1049 struct gpio_desc **descs; 1050 unsigned int i, didx, num_set; 1051 int ret; 1052 1053 bitmap_zero(vals, GPIO_V2_LINES_MAX); 1054 for (num_set = 0, i = 0; i < lr->num_lines; i++) { 1055 if (lv->mask & BIT_ULL(i)) { 1056 if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags)) 1057 return -EPERM; 1058 if (lv->bits & BIT_ULL(i)) 1059 __set_bit(num_set, vals); 1060 num_set++; 1061 descs = &lr->lines[i].desc; 1062 } 1063 } 1064 if (num_set == 0) 1065 return -EINVAL; 1066 1067 if (num_set != 1) { 1068 /* build compacted desc array and values */ 1069 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL); 1070 if (!descs) 1071 return -ENOMEM; 1072 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1073 if (lv->mask & BIT_ULL(i)) { 1074 descs[didx] = lr->lines[i].desc; 1075 didx++; 1076 } 1077 } 1078 } 1079 ret = gpiod_set_array_value_complex(false, true, num_set, 1080 descs, NULL, vals); 1081 1082 if (num_set != 1) 1083 kfree(descs); 1084 return ret; 1085 } 1086 1087 static long linereq_set_values(struct linereq *lr, void __user *ip) 1088 { 1089 struct gpio_v2_line_values lv; 1090 int ret; 1091 1092 if (copy_from_user(&lv, ip, sizeof(lv))) 1093 return -EFAULT; 1094 1095 mutex_lock(&lr->config_mutex); 1096 1097 ret = linereq_set_values_unlocked(lr, &lv); 1098 1099 mutex_unlock(&lr->config_mutex); 1100 1101 return ret; 1102 } 1103 1104 static long linereq_set_config_unlocked(struct linereq *lr, 1105 struct gpio_v2_line_config *lc) 1106 { 1107 struct gpio_desc *desc; 1108 unsigned int i; 1109 u64 flags; 1110 bool polarity_change; 1111 int ret; 1112 1113 for (i = 0; i < lr->num_lines; i++) { 1114 desc = lr->lines[i].desc; 1115 flags = gpio_v2_line_config_flags(lc, i); 1116 polarity_change = 1117 (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) != 1118 ((flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) != 0)); 1119 1120 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1121 /* 1122 * Lines have to be requested explicitly for input 1123 * or output, else the line will be treated "as is". 1124 */ 1125 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1126 int val = gpio_v2_line_config_output_value(lc, i); 1127 1128 edge_detector_stop(&lr->lines[i]); 1129 ret = gpiod_direction_output(desc, val); 1130 if (ret) 1131 return ret; 1132 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1133 ret = gpiod_direction_input(desc); 1134 if (ret) 1135 return ret; 1136 1137 ret = edge_detector_update(&lr->lines[i], lc, i, 1138 flags & GPIO_V2_LINE_EDGE_FLAGS, 1139 polarity_change); 1140 if (ret) 1141 return ret; 1142 } 1143 1144 blocking_notifier_call_chain(&desc->gdev->notifier, 1145 GPIO_V2_LINE_CHANGED_CONFIG, 1146 desc); 1147 } 1148 return 0; 1149 } 1150 1151 static long linereq_set_config(struct linereq *lr, void __user *ip) 1152 { 1153 struct gpio_v2_line_config lc; 1154 int ret; 1155 1156 if (copy_from_user(&lc, ip, sizeof(lc))) 1157 return -EFAULT; 1158 1159 ret = gpio_v2_line_config_validate(&lc, lr->num_lines); 1160 if (ret) 1161 return ret; 1162 1163 mutex_lock(&lr->config_mutex); 1164 1165 ret = linereq_set_config_unlocked(lr, &lc); 1166 1167 mutex_unlock(&lr->config_mutex); 1168 1169 return ret; 1170 } 1171 1172 static long linereq_ioctl(struct file *file, unsigned int cmd, 1173 unsigned long arg) 1174 { 1175 struct linereq *lr = file->private_data; 1176 void __user *ip = (void __user *)arg; 1177 1178 if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL) 1179 return linereq_get_values(lr, ip); 1180 else if (cmd == GPIO_V2_LINE_SET_VALUES_IOCTL) 1181 return linereq_set_values(lr, ip); 1182 else if (cmd == GPIO_V2_LINE_SET_CONFIG_IOCTL) 1183 return linereq_set_config(lr, ip); 1184 1185 return -EINVAL; 1186 } 1187 1188 #ifdef CONFIG_COMPAT 1189 static long linereq_ioctl_compat(struct file *file, unsigned int cmd, 1190 unsigned long arg) 1191 { 1192 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1193 } 1194 #endif 1195 1196 static __poll_t linereq_poll(struct file *file, 1197 struct poll_table_struct *wait) 1198 { 1199 struct linereq *lr = file->private_data; 1200 __poll_t events = 0; 1201 1202 poll_wait(file, &lr->wait, wait); 1203 1204 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events, 1205 &lr->wait.lock)) 1206 events = EPOLLIN | EPOLLRDNORM; 1207 1208 return events; 1209 } 1210 1211 static ssize_t linereq_read(struct file *file, 1212 char __user *buf, 1213 size_t count, 1214 loff_t *f_ps) 1215 { 1216 struct linereq *lr = file->private_data; 1217 struct gpio_v2_line_event le; 1218 ssize_t bytes_read = 0; 1219 int ret; 1220 1221 if (count < sizeof(le)) 1222 return -EINVAL; 1223 1224 do { 1225 spin_lock(&lr->wait.lock); 1226 if (kfifo_is_empty(&lr->events)) { 1227 if (bytes_read) { 1228 spin_unlock(&lr->wait.lock); 1229 return bytes_read; 1230 } 1231 1232 if (file->f_flags & O_NONBLOCK) { 1233 spin_unlock(&lr->wait.lock); 1234 return -EAGAIN; 1235 } 1236 1237 ret = wait_event_interruptible_locked(lr->wait, 1238 !kfifo_is_empty(&lr->events)); 1239 if (ret) { 1240 spin_unlock(&lr->wait.lock); 1241 return ret; 1242 } 1243 } 1244 1245 ret = kfifo_out(&lr->events, &le, 1); 1246 spin_unlock(&lr->wait.lock); 1247 if (ret != 1) { 1248 /* 1249 * This should never happen - we were holding the 1250 * lock from the moment we learned the fifo is no 1251 * longer empty until now. 1252 */ 1253 ret = -EIO; 1254 break; 1255 } 1256 1257 if (copy_to_user(buf + bytes_read, &le, sizeof(le))) 1258 return -EFAULT; 1259 bytes_read += sizeof(le); 1260 } while (count >= bytes_read + sizeof(le)); 1261 1262 return bytes_read; 1263 } 1264 1265 static void linereq_free(struct linereq *lr) 1266 { 1267 unsigned int i; 1268 1269 for (i = 0; i < lr->num_lines; i++) { 1270 edge_detector_stop(&lr->lines[i]); 1271 if (lr->lines[i].desc) 1272 gpiod_free(lr->lines[i].desc); 1273 } 1274 kfifo_free(&lr->events); 1275 kfree(lr->label); 1276 put_device(&lr->gdev->dev); 1277 kfree(lr); 1278 } 1279 1280 static int linereq_release(struct inode *inode, struct file *file) 1281 { 1282 struct linereq *lr = file->private_data; 1283 1284 linereq_free(lr); 1285 return 0; 1286 } 1287 1288 static const struct file_operations line_fileops = { 1289 .release = linereq_release, 1290 .read = linereq_read, 1291 .poll = linereq_poll, 1292 .owner = THIS_MODULE, 1293 .llseek = noop_llseek, 1294 .unlocked_ioctl = linereq_ioctl, 1295 #ifdef CONFIG_COMPAT 1296 .compat_ioctl = linereq_ioctl_compat, 1297 #endif 1298 }; 1299 1300 static int linereq_create(struct gpio_device *gdev, void __user *ip) 1301 { 1302 struct gpio_v2_line_request ulr; 1303 struct gpio_v2_line_config *lc; 1304 struct linereq *lr; 1305 struct file *file; 1306 u64 flags; 1307 unsigned int i; 1308 int fd, ret; 1309 1310 if (copy_from_user(&ulr, ip, sizeof(ulr))) 1311 return -EFAULT; 1312 1313 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX)) 1314 return -EINVAL; 1315 1316 if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding))) 1317 return -EINVAL; 1318 1319 lc = &ulr.config; 1320 ret = gpio_v2_line_config_validate(lc, ulr.num_lines); 1321 if (ret) 1322 return ret; 1323 1324 lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL); 1325 if (!lr) 1326 return -ENOMEM; 1327 1328 lr->gdev = gdev; 1329 get_device(&gdev->dev); 1330 1331 for (i = 0; i < ulr.num_lines; i++) { 1332 lr->lines[i].req = lr; 1333 WRITE_ONCE(lr->lines[i].sw_debounced, 0); 1334 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func); 1335 } 1336 1337 if (ulr.consumer[0] != '\0') { 1338 /* label is only initialized if consumer is set */ 1339 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1, 1340 GFP_KERNEL); 1341 if (!lr->label) { 1342 ret = -ENOMEM; 1343 goto out_free_linereq; 1344 } 1345 } 1346 1347 mutex_init(&lr->config_mutex); 1348 init_waitqueue_head(&lr->wait); 1349 lr->event_buffer_size = ulr.event_buffer_size; 1350 if (lr->event_buffer_size == 0) 1351 lr->event_buffer_size = ulr.num_lines * 16; 1352 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16) 1353 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16; 1354 1355 atomic_set(&lr->seqno, 0); 1356 lr->num_lines = ulr.num_lines; 1357 1358 /* Request each GPIO */ 1359 for (i = 0; i < ulr.num_lines; i++) { 1360 u32 offset = ulr.offsets[i]; 1361 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset); 1362 1363 if (IS_ERR(desc)) { 1364 ret = PTR_ERR(desc); 1365 goto out_free_linereq; 1366 } 1367 1368 ret = gpiod_request(desc, lr->label); 1369 if (ret) 1370 goto out_free_linereq; 1371 1372 lr->lines[i].desc = desc; 1373 flags = gpio_v2_line_config_flags(lc, i); 1374 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1375 1376 ret = gpiod_set_transitory(desc, false); 1377 if (ret < 0) 1378 goto out_free_linereq; 1379 1380 /* 1381 * Lines have to be requested explicitly for input 1382 * or output, else the line will be treated "as is". 1383 */ 1384 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1385 int val = gpio_v2_line_config_output_value(lc, i); 1386 1387 ret = gpiod_direction_output(desc, val); 1388 if (ret) 1389 goto out_free_linereq; 1390 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1391 ret = gpiod_direction_input(desc); 1392 if (ret) 1393 goto out_free_linereq; 1394 1395 ret = edge_detector_setup(&lr->lines[i], lc, i, 1396 flags & GPIO_V2_LINE_EDGE_FLAGS); 1397 if (ret) 1398 goto out_free_linereq; 1399 } 1400 1401 blocking_notifier_call_chain(&desc->gdev->notifier, 1402 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 1403 1404 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 1405 offset); 1406 } 1407 1408 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 1409 if (fd < 0) { 1410 ret = fd; 1411 goto out_free_linereq; 1412 } 1413 1414 file = anon_inode_getfile("gpio-line", &line_fileops, lr, 1415 O_RDONLY | O_CLOEXEC); 1416 if (IS_ERR(file)) { 1417 ret = PTR_ERR(file); 1418 goto out_put_unused_fd; 1419 } 1420 1421 ulr.fd = fd; 1422 if (copy_to_user(ip, &ulr, sizeof(ulr))) { 1423 /* 1424 * fput() will trigger the release() callback, so do not go onto 1425 * the regular error cleanup path here. 1426 */ 1427 fput(file); 1428 put_unused_fd(fd); 1429 return -EFAULT; 1430 } 1431 1432 fd_install(fd, file); 1433 1434 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 1435 lr->num_lines); 1436 1437 return 0; 1438 1439 out_put_unused_fd: 1440 put_unused_fd(fd); 1441 out_free_linereq: 1442 linereq_free(lr); 1443 return ret; 1444 } 1445 1446 #ifdef CONFIG_GPIO_CDEV_V1 1447 1448 /* 1449 * GPIO line event management 1450 */ 1451 1452 /** 1453 * struct lineevent_state - contains the state of a userspace event 1454 * @gdev: the GPIO device the event pertains to 1455 * @label: consumer label used to tag descriptors 1456 * @desc: the GPIO descriptor held by this event 1457 * @eflags: the event flags this line was requested with 1458 * @irq: the interrupt that trigger in response to events on this GPIO 1459 * @wait: wait queue that handles blocking reads of events 1460 * @events: KFIFO for the GPIO events 1461 * @timestamp: cache for the timestamp storing it between hardirq 1462 * and IRQ thread, used to bring the timestamp close to the actual 1463 * event 1464 */ 1465 struct lineevent_state { 1466 struct gpio_device *gdev; 1467 const char *label; 1468 struct gpio_desc *desc; 1469 u32 eflags; 1470 int irq; 1471 wait_queue_head_t wait; 1472 DECLARE_KFIFO(events, struct gpioevent_data, 16); 1473 u64 timestamp; 1474 }; 1475 1476 #define GPIOEVENT_REQUEST_VALID_FLAGS \ 1477 (GPIOEVENT_REQUEST_RISING_EDGE | \ 1478 GPIOEVENT_REQUEST_FALLING_EDGE) 1479 1480 static __poll_t lineevent_poll(struct file *file, 1481 struct poll_table_struct *wait) 1482 { 1483 struct lineevent_state *le = file->private_data; 1484 __poll_t events = 0; 1485 1486 poll_wait(file, &le->wait, wait); 1487 1488 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock)) 1489 events = EPOLLIN | EPOLLRDNORM; 1490 1491 return events; 1492 } 1493 1494 struct compat_gpioeevent_data { 1495 compat_u64 timestamp; 1496 u32 id; 1497 }; 1498 1499 static ssize_t lineevent_read(struct file *file, 1500 char __user *buf, 1501 size_t count, 1502 loff_t *f_ps) 1503 { 1504 struct lineevent_state *le = file->private_data; 1505 struct gpioevent_data ge; 1506 ssize_t bytes_read = 0; 1507 ssize_t ge_size; 1508 int ret; 1509 1510 /* 1511 * When compatible system call is being used the struct gpioevent_data, 1512 * in case of at least ia32, has different size due to the alignment 1513 * differences. Because we have first member 64 bits followed by one of 1514 * 32 bits there is no gap between them. The only difference is the 1515 * padding at the end of the data structure. Hence, we calculate the 1516 * actual sizeof() and pass this as an argument to copy_to_user() to 1517 * drop unneeded bytes from the output. 1518 */ 1519 if (compat_need_64bit_alignment_fixup()) 1520 ge_size = sizeof(struct compat_gpioeevent_data); 1521 else 1522 ge_size = sizeof(struct gpioevent_data); 1523 if (count < ge_size) 1524 return -EINVAL; 1525 1526 do { 1527 spin_lock(&le->wait.lock); 1528 if (kfifo_is_empty(&le->events)) { 1529 if (bytes_read) { 1530 spin_unlock(&le->wait.lock); 1531 return bytes_read; 1532 } 1533 1534 if (file->f_flags & O_NONBLOCK) { 1535 spin_unlock(&le->wait.lock); 1536 return -EAGAIN; 1537 } 1538 1539 ret = wait_event_interruptible_locked(le->wait, 1540 !kfifo_is_empty(&le->events)); 1541 if (ret) { 1542 spin_unlock(&le->wait.lock); 1543 return ret; 1544 } 1545 } 1546 1547 ret = kfifo_out(&le->events, &ge, 1); 1548 spin_unlock(&le->wait.lock); 1549 if (ret != 1) { 1550 /* 1551 * This should never happen - we were holding the lock 1552 * from the moment we learned the fifo is no longer 1553 * empty until now. 1554 */ 1555 ret = -EIO; 1556 break; 1557 } 1558 1559 if (copy_to_user(buf + bytes_read, &ge, ge_size)) 1560 return -EFAULT; 1561 bytes_read += ge_size; 1562 } while (count >= bytes_read + ge_size); 1563 1564 return bytes_read; 1565 } 1566 1567 static void lineevent_free(struct lineevent_state *le) 1568 { 1569 if (le->irq) 1570 free_irq(le->irq, le); 1571 if (le->desc) 1572 gpiod_free(le->desc); 1573 kfree(le->label); 1574 put_device(&le->gdev->dev); 1575 kfree(le); 1576 } 1577 1578 static int lineevent_release(struct inode *inode, struct file *file) 1579 { 1580 lineevent_free(file->private_data); 1581 return 0; 1582 } 1583 1584 static long lineevent_ioctl(struct file *file, unsigned int cmd, 1585 unsigned long arg) 1586 { 1587 struct lineevent_state *le = file->private_data; 1588 void __user *ip = (void __user *)arg; 1589 struct gpiohandle_data ghd; 1590 1591 /* 1592 * We can get the value for an event line but not set it, 1593 * because it is input by definition. 1594 */ 1595 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { 1596 int val; 1597 1598 memset(&ghd, 0, sizeof(ghd)); 1599 1600 val = gpiod_get_value_cansleep(le->desc); 1601 if (val < 0) 1602 return val; 1603 ghd.values[0] = val; 1604 1605 if (copy_to_user(ip, &ghd, sizeof(ghd))) 1606 return -EFAULT; 1607 1608 return 0; 1609 } 1610 return -EINVAL; 1611 } 1612 1613 #ifdef CONFIG_COMPAT 1614 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd, 1615 unsigned long arg) 1616 { 1617 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1618 } 1619 #endif 1620 1621 static const struct file_operations lineevent_fileops = { 1622 .release = lineevent_release, 1623 .read = lineevent_read, 1624 .poll = lineevent_poll, 1625 .owner = THIS_MODULE, 1626 .llseek = noop_llseek, 1627 .unlocked_ioctl = lineevent_ioctl, 1628 #ifdef CONFIG_COMPAT 1629 .compat_ioctl = lineevent_ioctl_compat, 1630 #endif 1631 }; 1632 1633 static irqreturn_t lineevent_irq_thread(int irq, void *p) 1634 { 1635 struct lineevent_state *le = p; 1636 struct gpioevent_data ge; 1637 int ret; 1638 1639 /* Do not leak kernel stack to userspace */ 1640 memset(&ge, 0, sizeof(ge)); 1641 1642 /* 1643 * We may be running from a nested threaded interrupt in which case 1644 * we didn't get the timestamp from lineevent_irq_handler(). 1645 */ 1646 if (!le->timestamp) 1647 ge.timestamp = ktime_get_ns(); 1648 else 1649 ge.timestamp = le->timestamp; 1650 1651 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE 1652 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 1653 int level = gpiod_get_value_cansleep(le->desc); 1654 1655 if (level) 1656 /* Emit low-to-high event */ 1657 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 1658 else 1659 /* Emit high-to-low event */ 1660 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 1661 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) { 1662 /* Emit low-to-high event */ 1663 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 1664 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 1665 /* Emit high-to-low event */ 1666 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 1667 } else { 1668 return IRQ_NONE; 1669 } 1670 1671 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge, 1672 1, &le->wait.lock); 1673 if (ret) 1674 wake_up_poll(&le->wait, EPOLLIN); 1675 else 1676 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 1677 1678 return IRQ_HANDLED; 1679 } 1680 1681 static irqreturn_t lineevent_irq_handler(int irq, void *p) 1682 { 1683 struct lineevent_state *le = p; 1684 1685 /* 1686 * Just store the timestamp in hardirq context so we get it as 1687 * close in time as possible to the actual event. 1688 */ 1689 le->timestamp = ktime_get_ns(); 1690 1691 return IRQ_WAKE_THREAD; 1692 } 1693 1694 static int lineevent_create(struct gpio_device *gdev, void __user *ip) 1695 { 1696 struct gpioevent_request eventreq; 1697 struct lineevent_state *le; 1698 struct gpio_desc *desc; 1699 struct file *file; 1700 u32 offset; 1701 u32 lflags; 1702 u32 eflags; 1703 int fd; 1704 int ret; 1705 int irq, irqflags = 0; 1706 1707 if (copy_from_user(&eventreq, ip, sizeof(eventreq))) 1708 return -EFAULT; 1709 1710 offset = eventreq.lineoffset; 1711 lflags = eventreq.handleflags; 1712 eflags = eventreq.eventflags; 1713 1714 desc = gpiochip_get_desc(gdev->chip, offset); 1715 if (IS_ERR(desc)) 1716 return PTR_ERR(desc); 1717 1718 /* Return an error if a unknown flag is set */ 1719 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) || 1720 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS)) 1721 return -EINVAL; 1722 1723 /* This is just wrong: we don't look for events on output lines */ 1724 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) || 1725 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 1726 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 1727 return -EINVAL; 1728 1729 /* Only one bias flag can be set. */ 1730 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 1731 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 1732 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 1733 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 1734 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 1735 return -EINVAL; 1736 1737 le = kzalloc(sizeof(*le), GFP_KERNEL); 1738 if (!le) 1739 return -ENOMEM; 1740 le->gdev = gdev; 1741 get_device(&gdev->dev); 1742 1743 if (eventreq.consumer_label[0] != '\0') { 1744 /* label is only initialized if consumer_label is set */ 1745 le->label = kstrndup(eventreq.consumer_label, 1746 sizeof(eventreq.consumer_label) - 1, 1747 GFP_KERNEL); 1748 if (!le->label) { 1749 ret = -ENOMEM; 1750 goto out_free_le; 1751 } 1752 } 1753 1754 ret = gpiod_request(desc, le->label); 1755 if (ret) 1756 goto out_free_le; 1757 le->desc = desc; 1758 le->eflags = eflags; 1759 1760 linehandle_flags_to_desc_flags(lflags, &desc->flags); 1761 1762 ret = gpiod_direction_input(desc); 1763 if (ret) 1764 goto out_free_le; 1765 1766 blocking_notifier_call_chain(&desc->gdev->notifier, 1767 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 1768 1769 irq = gpiod_to_irq(desc); 1770 if (irq <= 0) { 1771 ret = -ENODEV; 1772 goto out_free_le; 1773 } 1774 le->irq = irq; 1775 1776 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE) 1777 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 1778 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 1779 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE) 1780 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 1781 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 1782 irqflags |= IRQF_ONESHOT; 1783 1784 INIT_KFIFO(le->events); 1785 init_waitqueue_head(&le->wait); 1786 1787 /* Request a thread to read the events */ 1788 ret = request_threaded_irq(le->irq, 1789 lineevent_irq_handler, 1790 lineevent_irq_thread, 1791 irqflags, 1792 le->label, 1793 le); 1794 if (ret) 1795 goto out_free_le; 1796 1797 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 1798 if (fd < 0) { 1799 ret = fd; 1800 goto out_free_le; 1801 } 1802 1803 file = anon_inode_getfile("gpio-event", 1804 &lineevent_fileops, 1805 le, 1806 O_RDONLY | O_CLOEXEC); 1807 if (IS_ERR(file)) { 1808 ret = PTR_ERR(file); 1809 goto out_put_unused_fd; 1810 } 1811 1812 eventreq.fd = fd; 1813 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) { 1814 /* 1815 * fput() will trigger the release() callback, so do not go onto 1816 * the regular error cleanup path here. 1817 */ 1818 fput(file); 1819 put_unused_fd(fd); 1820 return -EFAULT; 1821 } 1822 1823 fd_install(fd, file); 1824 1825 return 0; 1826 1827 out_put_unused_fd: 1828 put_unused_fd(fd); 1829 out_free_le: 1830 lineevent_free(le); 1831 return ret; 1832 } 1833 1834 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2, 1835 struct gpioline_info *info_v1) 1836 { 1837 u64 flagsv2 = info_v2->flags; 1838 1839 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name)); 1840 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer)); 1841 info_v1->line_offset = info_v2->offset; 1842 info_v1->flags = 0; 1843 1844 if (flagsv2 & GPIO_V2_LINE_FLAG_USED) 1845 info_v1->flags |= GPIOLINE_FLAG_KERNEL; 1846 1847 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT) 1848 info_v1->flags |= GPIOLINE_FLAG_IS_OUT; 1849 1850 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 1851 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW; 1852 1853 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN) 1854 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN; 1855 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE) 1856 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE; 1857 1858 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP) 1859 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP; 1860 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) 1861 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN; 1862 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED) 1863 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE; 1864 } 1865 1866 static void gpio_v2_line_info_changed_to_v1( 1867 struct gpio_v2_line_info_changed *lic_v2, 1868 struct gpioline_info_changed *lic_v1) 1869 { 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 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &desc->flags)) 1946 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME; 1947 1948 debounce_period_us = READ_ONCE(desc->debounce_period_us); 1949 if (debounce_period_us) { 1950 info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; 1951 info->attrs[num_attrs].debounce_period_us = debounce_period_us; 1952 num_attrs++; 1953 } 1954 info->num_attrs = num_attrs; 1955 1956 spin_unlock_irqrestore(&gpio_lock, flags); 1957 } 1958 1959 struct gpio_chardev_data { 1960 struct gpio_device *gdev; 1961 wait_queue_head_t wait; 1962 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32); 1963 struct notifier_block lineinfo_changed_nb; 1964 unsigned long *watched_lines; 1965 #ifdef CONFIG_GPIO_CDEV_V1 1966 atomic_t watch_abi_version; 1967 #endif 1968 }; 1969 1970 #ifdef CONFIG_GPIO_CDEV_V1 1971 /* 1972 * returns 0 if the versions match, else the previously selected ABI version 1973 */ 1974 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata, 1975 unsigned int version) 1976 { 1977 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version); 1978 1979 if (abiv == version) 1980 return 0; 1981 1982 return abiv; 1983 } 1984 #endif 1985 1986 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, 1987 bool watch) 1988 { 1989 struct gpio_desc *desc; 1990 struct gpio_v2_line_info lineinfo; 1991 1992 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 1993 return -EFAULT; 1994 1995 if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding))) 1996 return -EINVAL; 1997 1998 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset); 1999 if (IS_ERR(desc)) 2000 return PTR_ERR(desc); 2001 2002 if (watch) { 2003 #ifdef CONFIG_GPIO_CDEV_V1 2004 if (lineinfo_ensure_abi_version(cdev, 2)) 2005 return -EPERM; 2006 #endif 2007 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines)) 2008 return -EBUSY; 2009 } 2010 gpio_desc_to_lineinfo(desc, &lineinfo); 2011 2012 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2013 if (watch) 2014 clear_bit(lineinfo.offset, cdev->watched_lines); 2015 return -EFAULT; 2016 } 2017 2018 return 0; 2019 } 2020 2021 /* 2022 * gpio_ioctl() - ioctl handler for the GPIO chardev 2023 */ 2024 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 2025 { 2026 struct gpio_chardev_data *cdev = file->private_data; 2027 struct gpio_device *gdev = cdev->gdev; 2028 struct gpio_chip *gc = gdev->chip; 2029 void __user *ip = (void __user *)arg; 2030 __u32 offset; 2031 2032 /* We fail any subsequent ioctl():s when the chip is gone */ 2033 if (!gc) 2034 return -ENODEV; 2035 2036 /* Fill in the struct and pass to userspace */ 2037 if (cmd == GPIO_GET_CHIPINFO_IOCTL) { 2038 struct gpiochip_info chipinfo; 2039 2040 memset(&chipinfo, 0, sizeof(chipinfo)); 2041 2042 strscpy(chipinfo.name, dev_name(&gdev->dev), 2043 sizeof(chipinfo.name)); 2044 strscpy(chipinfo.label, gdev->label, 2045 sizeof(chipinfo.label)); 2046 chipinfo.lines = gdev->ngpio; 2047 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo))) 2048 return -EFAULT; 2049 return 0; 2050 #ifdef CONFIG_GPIO_CDEV_V1 2051 } else if (cmd == GPIO_GET_LINEINFO_IOCTL) { 2052 struct gpio_desc *desc; 2053 struct gpioline_info lineinfo; 2054 struct gpio_v2_line_info lineinfo_v2; 2055 2056 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2057 return -EFAULT; 2058 2059 /* this doubles as a range check on line_offset */ 2060 desc = gpiochip_get_desc(gc, lineinfo.line_offset); 2061 if (IS_ERR(desc)) 2062 return PTR_ERR(desc); 2063 2064 gpio_desc_to_lineinfo(desc, &lineinfo_v2); 2065 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); 2066 2067 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) 2068 return -EFAULT; 2069 return 0; 2070 } else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) { 2071 return linehandle_create(gdev, ip); 2072 } else if (cmd == GPIO_GET_LINEEVENT_IOCTL) { 2073 return lineevent_create(gdev, ip); 2074 } else if (cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) { 2075 struct gpio_desc *desc; 2076 struct gpioline_info lineinfo; 2077 struct gpio_v2_line_info lineinfo_v2; 2078 2079 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2080 return -EFAULT; 2081 2082 /* this doubles as a range check on line_offset */ 2083 desc = gpiochip_get_desc(gc, lineinfo.line_offset); 2084 if (IS_ERR(desc)) 2085 return PTR_ERR(desc); 2086 2087 if (lineinfo_ensure_abi_version(cdev, 1)) 2088 return -EPERM; 2089 2090 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines)) 2091 return -EBUSY; 2092 2093 gpio_desc_to_lineinfo(desc, &lineinfo_v2); 2094 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); 2095 2096 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2097 clear_bit(lineinfo.line_offset, cdev->watched_lines); 2098 return -EFAULT; 2099 } 2100 2101 return 0; 2102 #endif /* CONFIG_GPIO_CDEV_V1 */ 2103 } else if (cmd == GPIO_V2_GET_LINEINFO_IOCTL || 2104 cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL) { 2105 return lineinfo_get(cdev, ip, 2106 cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL); 2107 } else if (cmd == GPIO_V2_GET_LINE_IOCTL) { 2108 return linereq_create(gdev, ip); 2109 } else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) { 2110 if (copy_from_user(&offset, ip, sizeof(offset))) 2111 return -EFAULT; 2112 2113 if (offset >= cdev->gdev->ngpio) 2114 return -EINVAL; 2115 2116 if (!test_and_clear_bit(offset, cdev->watched_lines)) 2117 return -EBUSY; 2118 2119 return 0; 2120 } 2121 return -EINVAL; 2122 } 2123 2124 #ifdef CONFIG_COMPAT 2125 static long gpio_ioctl_compat(struct file *file, unsigned int cmd, 2126 unsigned long arg) 2127 { 2128 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 2129 } 2130 #endif 2131 2132 static struct gpio_chardev_data * 2133 to_gpio_chardev_data(struct notifier_block *nb) 2134 { 2135 return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb); 2136 } 2137 2138 static int lineinfo_changed_notify(struct notifier_block *nb, 2139 unsigned long action, void *data) 2140 { 2141 struct gpio_chardev_data *cdev = to_gpio_chardev_data(nb); 2142 struct gpio_v2_line_info_changed chg; 2143 struct gpio_desc *desc = data; 2144 int ret; 2145 2146 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines)) 2147 return NOTIFY_DONE; 2148 2149 memset(&chg, 0, sizeof(chg)); 2150 chg.event_type = action; 2151 chg.timestamp_ns = ktime_get_ns(); 2152 gpio_desc_to_lineinfo(desc, &chg.info); 2153 2154 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock); 2155 if (ret) 2156 wake_up_poll(&cdev->wait, EPOLLIN); 2157 else 2158 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n"); 2159 2160 return NOTIFY_OK; 2161 } 2162 2163 static __poll_t lineinfo_watch_poll(struct file *file, 2164 struct poll_table_struct *pollt) 2165 { 2166 struct gpio_chardev_data *cdev = file->private_data; 2167 __poll_t events = 0; 2168 2169 poll_wait(file, &cdev->wait, pollt); 2170 2171 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events, 2172 &cdev->wait.lock)) 2173 events = EPOLLIN | EPOLLRDNORM; 2174 2175 return events; 2176 } 2177 2178 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, 2179 size_t count, loff_t *off) 2180 { 2181 struct gpio_chardev_data *cdev = file->private_data; 2182 struct gpio_v2_line_info_changed event; 2183 ssize_t bytes_read = 0; 2184 int ret; 2185 size_t event_size; 2186 2187 #ifndef CONFIG_GPIO_CDEV_V1 2188 event_size = sizeof(struct gpio_v2_line_info_changed); 2189 if (count < event_size) 2190 return -EINVAL; 2191 #endif 2192 2193 do { 2194 spin_lock(&cdev->wait.lock); 2195 if (kfifo_is_empty(&cdev->events)) { 2196 if (bytes_read) { 2197 spin_unlock(&cdev->wait.lock); 2198 return bytes_read; 2199 } 2200 2201 if (file->f_flags & O_NONBLOCK) { 2202 spin_unlock(&cdev->wait.lock); 2203 return -EAGAIN; 2204 } 2205 2206 ret = wait_event_interruptible_locked(cdev->wait, 2207 !kfifo_is_empty(&cdev->events)); 2208 if (ret) { 2209 spin_unlock(&cdev->wait.lock); 2210 return ret; 2211 } 2212 } 2213 #ifdef CONFIG_GPIO_CDEV_V1 2214 /* must be after kfifo check so watch_abi_version is set */ 2215 if (atomic_read(&cdev->watch_abi_version) == 2) 2216 event_size = sizeof(struct gpio_v2_line_info_changed); 2217 else 2218 event_size = sizeof(struct gpioline_info_changed); 2219 if (count < event_size) { 2220 spin_unlock(&cdev->wait.lock); 2221 return -EINVAL; 2222 } 2223 #endif 2224 ret = kfifo_out(&cdev->events, &event, 1); 2225 spin_unlock(&cdev->wait.lock); 2226 if (ret != 1) { 2227 ret = -EIO; 2228 break; 2229 /* We should never get here. See lineevent_read(). */ 2230 } 2231 2232 #ifdef CONFIG_GPIO_CDEV_V1 2233 if (event_size == sizeof(struct gpio_v2_line_info_changed)) { 2234 if (copy_to_user(buf + bytes_read, &event, event_size)) 2235 return -EFAULT; 2236 } else { 2237 struct gpioline_info_changed event_v1; 2238 2239 gpio_v2_line_info_changed_to_v1(&event, &event_v1); 2240 if (copy_to_user(buf + bytes_read, &event_v1, 2241 event_size)) 2242 return -EFAULT; 2243 } 2244 #else 2245 if (copy_to_user(buf + bytes_read, &event, event_size)) 2246 return -EFAULT; 2247 #endif 2248 bytes_read += event_size; 2249 } while (count >= bytes_read + sizeof(event)); 2250 2251 return bytes_read; 2252 } 2253 2254 /** 2255 * gpio_chrdev_open() - open the chardev for ioctl operations 2256 * @inode: inode for this chardev 2257 * @file: file struct for storing private data 2258 * Returns 0 on success 2259 */ 2260 static int gpio_chrdev_open(struct inode *inode, struct file *file) 2261 { 2262 struct gpio_device *gdev = container_of(inode->i_cdev, 2263 struct gpio_device, chrdev); 2264 struct gpio_chardev_data *cdev; 2265 int ret = -ENOMEM; 2266 2267 /* Fail on open if the backing gpiochip is gone */ 2268 if (!gdev->chip) 2269 return -ENODEV; 2270 2271 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL); 2272 if (!cdev) 2273 return -ENOMEM; 2274 2275 cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL); 2276 if (!cdev->watched_lines) 2277 goto out_free_cdev; 2278 2279 init_waitqueue_head(&cdev->wait); 2280 INIT_KFIFO(cdev->events); 2281 cdev->gdev = gdev; 2282 2283 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify; 2284 ret = blocking_notifier_chain_register(&gdev->notifier, 2285 &cdev->lineinfo_changed_nb); 2286 if (ret) 2287 goto out_free_bitmap; 2288 2289 get_device(&gdev->dev); 2290 file->private_data = cdev; 2291 2292 ret = nonseekable_open(inode, file); 2293 if (ret) 2294 goto out_unregister_notifier; 2295 2296 return ret; 2297 2298 out_unregister_notifier: 2299 blocking_notifier_chain_unregister(&gdev->notifier, 2300 &cdev->lineinfo_changed_nb); 2301 out_free_bitmap: 2302 bitmap_free(cdev->watched_lines); 2303 out_free_cdev: 2304 kfree(cdev); 2305 return ret; 2306 } 2307 2308 /** 2309 * gpio_chrdev_release() - close chardev after ioctl operations 2310 * @inode: inode for this chardev 2311 * @file: file struct for storing private data 2312 * Returns 0 on success 2313 */ 2314 static int gpio_chrdev_release(struct inode *inode, struct file *file) 2315 { 2316 struct gpio_chardev_data *cdev = file->private_data; 2317 struct gpio_device *gdev = cdev->gdev; 2318 2319 bitmap_free(cdev->watched_lines); 2320 blocking_notifier_chain_unregister(&gdev->notifier, 2321 &cdev->lineinfo_changed_nb); 2322 put_device(&gdev->dev); 2323 kfree(cdev); 2324 2325 return 0; 2326 } 2327 2328 static const struct file_operations gpio_fileops = { 2329 .release = gpio_chrdev_release, 2330 .open = gpio_chrdev_open, 2331 .poll = lineinfo_watch_poll, 2332 .read = lineinfo_watch_read, 2333 .owner = THIS_MODULE, 2334 .llseek = no_llseek, 2335 .unlocked_ioctl = gpio_ioctl, 2336 #ifdef CONFIG_COMPAT 2337 .compat_ioctl = gpio_ioctl_compat, 2338 #endif 2339 }; 2340 2341 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt) 2342 { 2343 int ret; 2344 2345 cdev_init(&gdev->chrdev, &gpio_fileops); 2346 gdev->chrdev.owner = THIS_MODULE; 2347 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id); 2348 2349 ret = cdev_device_add(&gdev->chrdev, &gdev->dev); 2350 if (ret) 2351 return ret; 2352 2353 chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n", 2354 MAJOR(devt), gdev->id); 2355 2356 return 0; 2357 } 2358 2359 void gpiolib_cdev_unregister(struct gpio_device *gdev) 2360 { 2361 cdev_device_del(&gdev->chrdev, &gdev->dev); 2362 } 2363