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_user(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 /* 432 * eflags is set by edge_detector_setup(), edge_detector_stop() and 433 * edge_detector_update(), which are themselves mutually exclusive, 434 * and is accessed by edge_irq_thread() and debounce_work_func(), 435 * which can both live with a slightly stale value. 436 */ 437 u64 eflags; 438 /* 439 * timestamp_ns and req_seqno are accessed only by 440 * edge_irq_handler() and edge_irq_thread(), which are themselves 441 * mutually exclusive, so no additional protection is necessary. 442 */ 443 u64 timestamp_ns; 444 u32 req_seqno; 445 /* 446 * line_seqno is accessed by either edge_irq_thread() or 447 * debounce_work_func(), which are themselves mutually exclusive, 448 * so no additional protection is necessary. 449 */ 450 u32 line_seqno; 451 /* 452 * -- debouncer specific fields -- 453 */ 454 struct delayed_work work; 455 /* 456 * sw_debounce is accessed by linereq_set_config(), which is the 457 * only setter, and linereq_get_values(), which can live with a 458 * slightly stale value. 459 */ 460 unsigned int sw_debounced; 461 /* 462 * level is accessed by debounce_work_func(), which is the only 463 * setter, and linereq_get_values() which can live with a slightly 464 * stale value. 465 */ 466 unsigned int level; 467 }; 468 469 /** 470 * struct linereq - contains the state of a userspace line request 471 * @gdev: the GPIO device the line request pertains to 472 * @label: consumer label used to tag GPIO descriptors 473 * @num_lines: the number of lines in the lines array 474 * @wait: wait queue that handles blocking reads of events 475 * @event_buffer_size: the number of elements allocated in @events 476 * @events: KFIFO for the GPIO events 477 * @seqno: the sequence number for edge events generated on all lines in 478 * this line request. Note that this is not used when @num_lines is 1, as 479 * the line_seqno is then the same and is cheaper to calculate. 480 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency 481 * of configuration, particularly multi-step accesses to desc flags. 482 * @lines: the lines held by this line request, with @num_lines elements. 483 */ 484 struct linereq { 485 struct gpio_device *gdev; 486 const char *label; 487 u32 num_lines; 488 wait_queue_head_t wait; 489 u32 event_buffer_size; 490 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event); 491 atomic_t seqno; 492 struct mutex config_mutex; 493 struct line lines[]; 494 }; 495 496 #define GPIO_V2_LINE_BIAS_FLAGS \ 497 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \ 498 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \ 499 GPIO_V2_LINE_FLAG_BIAS_DISABLED) 500 501 #define GPIO_V2_LINE_DIRECTION_FLAGS \ 502 (GPIO_V2_LINE_FLAG_INPUT | \ 503 GPIO_V2_LINE_FLAG_OUTPUT) 504 505 #define GPIO_V2_LINE_DRIVE_FLAGS \ 506 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \ 507 GPIO_V2_LINE_FLAG_OPEN_SOURCE) 508 509 #define GPIO_V2_LINE_EDGE_FLAGS \ 510 (GPIO_V2_LINE_FLAG_EDGE_RISING | \ 511 GPIO_V2_LINE_FLAG_EDGE_FALLING) 512 513 #define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS 514 515 #define GPIO_V2_LINE_VALID_FLAGS \ 516 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ 517 GPIO_V2_LINE_DIRECTION_FLAGS | \ 518 GPIO_V2_LINE_DRIVE_FLAGS | \ 519 GPIO_V2_LINE_EDGE_FLAGS | \ 520 GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \ 521 GPIO_V2_LINE_BIAS_FLAGS) 522 523 static void linereq_put_event(struct linereq *lr, 524 struct gpio_v2_line_event *le) 525 { 526 bool overflow = false; 527 528 spin_lock(&lr->wait.lock); 529 if (kfifo_is_full(&lr->events)) { 530 overflow = true; 531 kfifo_skip(&lr->events); 532 } 533 kfifo_in(&lr->events, le, 1); 534 spin_unlock(&lr->wait.lock); 535 if (!overflow) 536 wake_up_poll(&lr->wait, EPOLLIN); 537 else 538 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 539 } 540 541 static u64 line_event_timestamp(struct line *line) 542 { 543 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags)) 544 return ktime_get_real_ns(); 545 546 return ktime_get_ns(); 547 } 548 549 static irqreturn_t edge_irq_thread(int irq, void *p) 550 { 551 struct line *line = p; 552 struct linereq *lr = line->req; 553 struct gpio_v2_line_event le; 554 u64 eflags; 555 556 /* Do not leak kernel stack to userspace */ 557 memset(&le, 0, sizeof(le)); 558 559 if (line->timestamp_ns) { 560 le.timestamp_ns = line->timestamp_ns; 561 } else { 562 /* 563 * We may be running from a nested threaded interrupt in 564 * which case we didn't get the timestamp from 565 * edge_irq_handler(). 566 */ 567 le.timestamp_ns = line_event_timestamp(line); 568 if (lr->num_lines != 1) 569 line->req_seqno = atomic_inc_return(&lr->seqno); 570 } 571 line->timestamp_ns = 0; 572 573 eflags = READ_ONCE(line->eflags); 574 if (eflags == GPIO_V2_LINE_FLAG_EDGE_BOTH) { 575 int level = gpiod_get_value_cansleep(line->desc); 576 577 if (level) 578 /* Emit low-to-high event */ 579 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 580 else 581 /* Emit high-to-low event */ 582 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 583 } else if (eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) { 584 /* Emit low-to-high event */ 585 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 586 } else if (eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) { 587 /* Emit high-to-low event */ 588 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 589 } else { 590 return IRQ_NONE; 591 } 592 line->line_seqno++; 593 le.line_seqno = line->line_seqno; 594 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno; 595 le.offset = gpio_chip_hwgpio(line->desc); 596 597 linereq_put_event(lr, &le); 598 599 return IRQ_HANDLED; 600 } 601 602 static irqreturn_t edge_irq_handler(int irq, void *p) 603 { 604 struct line *line = p; 605 struct linereq *lr = line->req; 606 607 /* 608 * Just store the timestamp in hardirq context so we get it as 609 * close in time as possible to the actual event. 610 */ 611 line->timestamp_ns = line_event_timestamp(line); 612 613 if (lr->num_lines != 1) 614 line->req_seqno = atomic_inc_return(&lr->seqno); 615 616 return IRQ_WAKE_THREAD; 617 } 618 619 /* 620 * returns the current debounced logical value. 621 */ 622 static bool debounced_value(struct line *line) 623 { 624 bool value; 625 626 /* 627 * minor race - debouncer may be stopped here, so edge_detector_stop() 628 * must leave the value unchanged so the following will read the level 629 * from when the debouncer was last running. 630 */ 631 value = READ_ONCE(line->level); 632 633 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags)) 634 value = !value; 635 636 return value; 637 } 638 639 static irqreturn_t debounce_irq_handler(int irq, void *p) 640 { 641 struct line *line = p; 642 643 mod_delayed_work(system_wq, &line->work, 644 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); 645 646 return IRQ_HANDLED; 647 } 648 649 static void debounce_work_func(struct work_struct *work) 650 { 651 struct gpio_v2_line_event le; 652 struct line *line = container_of(work, struct line, work.work); 653 struct linereq *lr; 654 int level; 655 u64 eflags; 656 657 level = gpiod_get_raw_value_cansleep(line->desc); 658 if (level < 0) { 659 pr_debug_ratelimited("debouncer failed to read line value\n"); 660 return; 661 } 662 663 if (READ_ONCE(line->level) == level) 664 return; 665 666 WRITE_ONCE(line->level, level); 667 668 /* -- edge detection -- */ 669 eflags = READ_ONCE(line->eflags); 670 if (!eflags) 671 return; 672 673 /* switch from physical level to logical - if they differ */ 674 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags)) 675 level = !level; 676 677 /* ignore edges that are not being monitored */ 678 if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) || 679 ((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level)) 680 return; 681 682 /* Do not leak kernel stack to userspace */ 683 memset(&le, 0, sizeof(le)); 684 685 lr = line->req; 686 le.timestamp_ns = line_event_timestamp(line); 687 le.offset = gpio_chip_hwgpio(line->desc); 688 line->line_seqno++; 689 le.line_seqno = line->line_seqno; 690 le.seqno = (lr->num_lines == 1) ? 691 le.line_seqno : atomic_inc_return(&lr->seqno); 692 693 if (level) 694 /* Emit low-to-high event */ 695 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 696 else 697 /* Emit high-to-low event */ 698 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 699 700 linereq_put_event(lr, &le); 701 } 702 703 static int debounce_setup(struct line *line, 704 unsigned int debounce_period_us) 705 { 706 unsigned long irqflags; 707 int ret, level, irq; 708 709 /* try hardware */ 710 ret = gpiod_set_debounce(line->desc, debounce_period_us); 711 if (!ret) { 712 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 713 return ret; 714 } 715 if (ret != -ENOTSUPP) 716 return ret; 717 718 if (debounce_period_us) { 719 /* setup software debounce */ 720 level = gpiod_get_raw_value_cansleep(line->desc); 721 if (level < 0) 722 return level; 723 724 irq = gpiod_to_irq(line->desc); 725 if (irq < 0) 726 return -ENXIO; 727 728 WRITE_ONCE(line->level, level); 729 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING; 730 ret = request_irq(irq, debounce_irq_handler, irqflags, 731 line->req->label, line); 732 if (ret) 733 return ret; 734 735 WRITE_ONCE(line->sw_debounced, 1); 736 line->irq = irq; 737 } 738 return 0; 739 } 740 741 static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc, 742 unsigned int line_idx) 743 { 744 unsigned int i; 745 u64 mask = BIT_ULL(line_idx); 746 747 for (i = 0; i < lc->num_attrs; i++) { 748 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 749 (lc->attrs[i].mask & mask)) 750 return true; 751 } 752 return false; 753 } 754 755 static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc, 756 unsigned int line_idx) 757 { 758 unsigned int i; 759 u64 mask = BIT_ULL(line_idx); 760 761 for (i = 0; i < lc->num_attrs; i++) { 762 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 763 (lc->attrs[i].mask & mask)) 764 return lc->attrs[i].attr.debounce_period_us; 765 } 766 return 0; 767 } 768 769 static void edge_detector_stop(struct line *line) 770 { 771 if (line->irq) { 772 free_irq(line->irq, line); 773 line->irq = 0; 774 } 775 776 cancel_delayed_work_sync(&line->work); 777 WRITE_ONCE(line->sw_debounced, 0); 778 WRITE_ONCE(line->eflags, 0); 779 if (line->desc) 780 WRITE_ONCE(line->desc->debounce_period_us, 0); 781 /* do not change line->level - see comment in debounced_value() */ 782 } 783 784 static int edge_detector_setup(struct line *line, 785 struct gpio_v2_line_config *lc, 786 unsigned int line_idx, 787 u64 eflags) 788 { 789 u32 debounce_period_us; 790 unsigned long irqflags = 0; 791 int irq, ret; 792 793 if (eflags && !kfifo_initialized(&line->req->events)) { 794 ret = kfifo_alloc(&line->req->events, 795 line->req->event_buffer_size, GFP_KERNEL); 796 if (ret) 797 return ret; 798 } 799 WRITE_ONCE(line->eflags, eflags); 800 if (gpio_v2_line_config_debounced(lc, line_idx)) { 801 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx); 802 ret = debounce_setup(line, debounce_period_us); 803 if (ret) 804 return ret; 805 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 806 } 807 808 /* detection disabled or sw debouncer will provide edge detection */ 809 if (!eflags || READ_ONCE(line->sw_debounced)) 810 return 0; 811 812 irq = gpiod_to_irq(line->desc); 813 if (irq < 0) 814 return -ENXIO; 815 816 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING) 817 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 818 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 819 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING) 820 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 821 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 822 irqflags |= IRQF_ONESHOT; 823 824 /* Request a thread to read the events */ 825 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread, 826 irqflags, line->req->label, line); 827 if (ret) 828 return ret; 829 830 line->irq = irq; 831 return 0; 832 } 833 834 static int edge_detector_update(struct line *line, 835 struct gpio_v2_line_config *lc, 836 unsigned int line_idx, 837 u64 eflags, bool polarity_change) 838 { 839 unsigned int debounce_period_us = 840 gpio_v2_line_config_debounce_period(lc, line_idx); 841 842 if ((READ_ONCE(line->eflags) == eflags) && !polarity_change && 843 (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us)) 844 return 0; 845 846 /* sw debounced and still will be...*/ 847 if (debounce_period_us && READ_ONCE(line->sw_debounced)) { 848 WRITE_ONCE(line->eflags, eflags); 849 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 850 return 0; 851 } 852 853 /* reconfiguring edge detection or sw debounce being disabled */ 854 if ((line->irq && !READ_ONCE(line->sw_debounced)) || 855 (!debounce_period_us && READ_ONCE(line->sw_debounced))) 856 edge_detector_stop(line); 857 858 return edge_detector_setup(line, lc, line_idx, eflags); 859 } 860 861 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc, 862 unsigned int line_idx) 863 { 864 unsigned int i; 865 u64 mask = BIT_ULL(line_idx); 866 867 for (i = 0; i < lc->num_attrs; i++) { 868 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) && 869 (lc->attrs[i].mask & mask)) 870 return lc->attrs[i].attr.flags; 871 } 872 return lc->flags; 873 } 874 875 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc, 876 unsigned int line_idx) 877 { 878 unsigned int i; 879 u64 mask = BIT_ULL(line_idx); 880 881 for (i = 0; i < lc->num_attrs; i++) { 882 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) && 883 (lc->attrs[i].mask & mask)) 884 return !!(lc->attrs[i].attr.values & mask); 885 } 886 return 0; 887 } 888 889 static int gpio_v2_line_flags_validate(u64 flags) 890 { 891 /* Return an error if an unknown flag is set */ 892 if (flags & ~GPIO_V2_LINE_VALID_FLAGS) 893 return -EINVAL; 894 895 /* 896 * Do not allow both INPUT and OUTPUT flags to be set as they are 897 * contradictory. 898 */ 899 if ((flags & GPIO_V2_LINE_FLAG_INPUT) && 900 (flags & GPIO_V2_LINE_FLAG_OUTPUT)) 901 return -EINVAL; 902 903 /* Edge detection requires explicit input. */ 904 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) && 905 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 906 return -EINVAL; 907 908 /* 909 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single 910 * request. If the hardware actually supports enabling both at the 911 * same time the electrical result would be disastrous. 912 */ 913 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) && 914 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE)) 915 return -EINVAL; 916 917 /* Drive requires explicit output direction. */ 918 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) && 919 !(flags & GPIO_V2_LINE_FLAG_OUTPUT)) 920 return -EINVAL; 921 922 /* Bias requires explicit direction. */ 923 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) && 924 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS)) 925 return -EINVAL; 926 927 /* Only one bias flag can be set. */ 928 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) && 929 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | 930 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) || 931 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) && 932 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) 933 return -EINVAL; 934 935 return 0; 936 } 937 938 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc, 939 unsigned int num_lines) 940 { 941 unsigned int i; 942 u64 flags; 943 int ret; 944 945 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX) 946 return -EINVAL; 947 948 if (memchr_inv(lc->padding, 0, sizeof(lc->padding))) 949 return -EINVAL; 950 951 for (i = 0; i < num_lines; i++) { 952 flags = gpio_v2_line_config_flags(lc, i); 953 ret = gpio_v2_line_flags_validate(flags); 954 if (ret) 955 return ret; 956 957 /* debounce requires explicit input */ 958 if (gpio_v2_line_config_debounced(lc, i) && 959 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 960 return -EINVAL; 961 } 962 return 0; 963 } 964 965 static void gpio_v2_line_config_flags_to_desc_flags(u64 flags, 966 unsigned long *flagsp) 967 { 968 assign_bit(FLAG_ACTIVE_LOW, flagsp, 969 flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW); 970 971 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) 972 set_bit(FLAG_IS_OUT, flagsp); 973 else if (flags & GPIO_V2_LINE_FLAG_INPUT) 974 clear_bit(FLAG_IS_OUT, flagsp); 975 976 assign_bit(FLAG_EDGE_RISING, flagsp, 977 flags & GPIO_V2_LINE_FLAG_EDGE_RISING); 978 assign_bit(FLAG_EDGE_FALLING, flagsp, 979 flags & GPIO_V2_LINE_FLAG_EDGE_FALLING); 980 981 assign_bit(FLAG_OPEN_DRAIN, flagsp, 982 flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN); 983 assign_bit(FLAG_OPEN_SOURCE, flagsp, 984 flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE); 985 986 assign_bit(FLAG_PULL_UP, flagsp, 987 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP); 988 assign_bit(FLAG_PULL_DOWN, flagsp, 989 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN); 990 assign_bit(FLAG_BIAS_DISABLE, flagsp, 991 flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED); 992 993 assign_bit(FLAG_EVENT_CLOCK_REALTIME, flagsp, 994 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME); 995 } 996 997 static long linereq_get_values(struct linereq *lr, void __user *ip) 998 { 999 struct gpio_v2_line_values lv; 1000 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1001 struct gpio_desc **descs; 1002 unsigned int i, didx, num_get; 1003 bool val; 1004 int ret; 1005 1006 /* NOTE: It's ok to read values of output lines. */ 1007 if (copy_from_user(&lv, ip, sizeof(lv))) 1008 return -EFAULT; 1009 1010 for (num_get = 0, i = 0; i < lr->num_lines; i++) { 1011 if (lv.mask & BIT_ULL(i)) { 1012 num_get++; 1013 descs = &lr->lines[i].desc; 1014 } 1015 } 1016 1017 if (num_get == 0) 1018 return -EINVAL; 1019 1020 if (num_get != 1) { 1021 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL); 1022 if (!descs) 1023 return -ENOMEM; 1024 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1025 if (lv.mask & BIT_ULL(i)) { 1026 descs[didx] = lr->lines[i].desc; 1027 didx++; 1028 } 1029 } 1030 } 1031 ret = gpiod_get_array_value_complex(false, true, num_get, 1032 descs, NULL, vals); 1033 1034 if (num_get != 1) 1035 kfree(descs); 1036 if (ret) 1037 return ret; 1038 1039 lv.bits = 0; 1040 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1041 if (lv.mask & BIT_ULL(i)) { 1042 if (lr->lines[i].sw_debounced) 1043 val = debounced_value(&lr->lines[i]); 1044 else 1045 val = test_bit(didx, vals); 1046 if (val) 1047 lv.bits |= BIT_ULL(i); 1048 didx++; 1049 } 1050 } 1051 1052 if (copy_to_user(ip, &lv, sizeof(lv))) 1053 return -EFAULT; 1054 1055 return 0; 1056 } 1057 1058 static long linereq_set_values_unlocked(struct linereq *lr, 1059 struct gpio_v2_line_values *lv) 1060 { 1061 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1062 struct gpio_desc **descs; 1063 unsigned int i, didx, num_set; 1064 int ret; 1065 1066 bitmap_zero(vals, GPIO_V2_LINES_MAX); 1067 for (num_set = 0, i = 0; i < lr->num_lines; i++) { 1068 if (lv->mask & BIT_ULL(i)) { 1069 if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags)) 1070 return -EPERM; 1071 if (lv->bits & BIT_ULL(i)) 1072 __set_bit(num_set, vals); 1073 num_set++; 1074 descs = &lr->lines[i].desc; 1075 } 1076 } 1077 if (num_set == 0) 1078 return -EINVAL; 1079 1080 if (num_set != 1) { 1081 /* build compacted desc array and values */ 1082 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL); 1083 if (!descs) 1084 return -ENOMEM; 1085 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1086 if (lv->mask & BIT_ULL(i)) { 1087 descs[didx] = lr->lines[i].desc; 1088 didx++; 1089 } 1090 } 1091 } 1092 ret = gpiod_set_array_value_complex(false, true, num_set, 1093 descs, NULL, vals); 1094 1095 if (num_set != 1) 1096 kfree(descs); 1097 return ret; 1098 } 1099 1100 static long linereq_set_values(struct linereq *lr, void __user *ip) 1101 { 1102 struct gpio_v2_line_values lv; 1103 int ret; 1104 1105 if (copy_from_user(&lv, ip, sizeof(lv))) 1106 return -EFAULT; 1107 1108 mutex_lock(&lr->config_mutex); 1109 1110 ret = linereq_set_values_unlocked(lr, &lv); 1111 1112 mutex_unlock(&lr->config_mutex); 1113 1114 return ret; 1115 } 1116 1117 static long linereq_set_config_unlocked(struct linereq *lr, 1118 struct gpio_v2_line_config *lc) 1119 { 1120 struct gpio_desc *desc; 1121 unsigned int i; 1122 u64 flags; 1123 bool polarity_change; 1124 int ret; 1125 1126 for (i = 0; i < lr->num_lines; i++) { 1127 desc = lr->lines[i].desc; 1128 flags = gpio_v2_line_config_flags(lc, i); 1129 polarity_change = 1130 (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) != 1131 ((flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) != 0)); 1132 1133 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1134 /* 1135 * Lines have to be requested explicitly for input 1136 * or output, else the line will be treated "as is". 1137 */ 1138 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1139 int val = gpio_v2_line_config_output_value(lc, i); 1140 1141 edge_detector_stop(&lr->lines[i]); 1142 ret = gpiod_direction_output(desc, val); 1143 if (ret) 1144 return ret; 1145 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1146 ret = gpiod_direction_input(desc); 1147 if (ret) 1148 return ret; 1149 1150 ret = edge_detector_update(&lr->lines[i], lc, i, 1151 flags & GPIO_V2_LINE_EDGE_FLAGS, 1152 polarity_change); 1153 if (ret) 1154 return ret; 1155 } 1156 1157 blocking_notifier_call_chain(&desc->gdev->notifier, 1158 GPIO_V2_LINE_CHANGED_CONFIG, 1159 desc); 1160 } 1161 return 0; 1162 } 1163 1164 static long linereq_set_config(struct linereq *lr, void __user *ip) 1165 { 1166 struct gpio_v2_line_config lc; 1167 int ret; 1168 1169 if (copy_from_user(&lc, ip, sizeof(lc))) 1170 return -EFAULT; 1171 1172 ret = gpio_v2_line_config_validate(&lc, lr->num_lines); 1173 if (ret) 1174 return ret; 1175 1176 mutex_lock(&lr->config_mutex); 1177 1178 ret = linereq_set_config_unlocked(lr, &lc); 1179 1180 mutex_unlock(&lr->config_mutex); 1181 1182 return ret; 1183 } 1184 1185 static long linereq_ioctl(struct file *file, unsigned int cmd, 1186 unsigned long arg) 1187 { 1188 struct linereq *lr = file->private_data; 1189 void __user *ip = (void __user *)arg; 1190 1191 if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL) 1192 return linereq_get_values(lr, ip); 1193 else if (cmd == GPIO_V2_LINE_SET_VALUES_IOCTL) 1194 return linereq_set_values(lr, ip); 1195 else if (cmd == GPIO_V2_LINE_SET_CONFIG_IOCTL) 1196 return linereq_set_config(lr, ip); 1197 1198 return -EINVAL; 1199 } 1200 1201 #ifdef CONFIG_COMPAT 1202 static long linereq_ioctl_compat(struct file *file, unsigned int cmd, 1203 unsigned long arg) 1204 { 1205 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1206 } 1207 #endif 1208 1209 static __poll_t linereq_poll(struct file *file, 1210 struct poll_table_struct *wait) 1211 { 1212 struct linereq *lr = file->private_data; 1213 __poll_t events = 0; 1214 1215 poll_wait(file, &lr->wait, wait); 1216 1217 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events, 1218 &lr->wait.lock)) 1219 events = EPOLLIN | EPOLLRDNORM; 1220 1221 return events; 1222 } 1223 1224 static ssize_t linereq_read(struct file *file, 1225 char __user *buf, 1226 size_t count, 1227 loff_t *f_ps) 1228 { 1229 struct linereq *lr = file->private_data; 1230 struct gpio_v2_line_event le; 1231 ssize_t bytes_read = 0; 1232 int ret; 1233 1234 if (count < sizeof(le)) 1235 return -EINVAL; 1236 1237 do { 1238 spin_lock(&lr->wait.lock); 1239 if (kfifo_is_empty(&lr->events)) { 1240 if (bytes_read) { 1241 spin_unlock(&lr->wait.lock); 1242 return bytes_read; 1243 } 1244 1245 if (file->f_flags & O_NONBLOCK) { 1246 spin_unlock(&lr->wait.lock); 1247 return -EAGAIN; 1248 } 1249 1250 ret = wait_event_interruptible_locked(lr->wait, 1251 !kfifo_is_empty(&lr->events)); 1252 if (ret) { 1253 spin_unlock(&lr->wait.lock); 1254 return ret; 1255 } 1256 } 1257 1258 ret = kfifo_out(&lr->events, &le, 1); 1259 spin_unlock(&lr->wait.lock); 1260 if (ret != 1) { 1261 /* 1262 * This should never happen - we were holding the 1263 * lock from the moment we learned the fifo is no 1264 * longer empty until now. 1265 */ 1266 ret = -EIO; 1267 break; 1268 } 1269 1270 if (copy_to_user(buf + bytes_read, &le, sizeof(le))) 1271 return -EFAULT; 1272 bytes_read += sizeof(le); 1273 } while (count >= bytes_read + sizeof(le)); 1274 1275 return bytes_read; 1276 } 1277 1278 static void linereq_free(struct linereq *lr) 1279 { 1280 unsigned int i; 1281 1282 for (i = 0; i < lr->num_lines; i++) { 1283 edge_detector_stop(&lr->lines[i]); 1284 if (lr->lines[i].desc) 1285 gpiod_free(lr->lines[i].desc); 1286 } 1287 kfifo_free(&lr->events); 1288 kfree(lr->label); 1289 put_device(&lr->gdev->dev); 1290 kfree(lr); 1291 } 1292 1293 static int linereq_release(struct inode *inode, struct file *file) 1294 { 1295 struct linereq *lr = file->private_data; 1296 1297 linereq_free(lr); 1298 return 0; 1299 } 1300 1301 static const struct file_operations line_fileops = { 1302 .release = linereq_release, 1303 .read = linereq_read, 1304 .poll = linereq_poll, 1305 .owner = THIS_MODULE, 1306 .llseek = noop_llseek, 1307 .unlocked_ioctl = linereq_ioctl, 1308 #ifdef CONFIG_COMPAT 1309 .compat_ioctl = linereq_ioctl_compat, 1310 #endif 1311 }; 1312 1313 static int linereq_create(struct gpio_device *gdev, void __user *ip) 1314 { 1315 struct gpio_v2_line_request ulr; 1316 struct gpio_v2_line_config *lc; 1317 struct linereq *lr; 1318 struct file *file; 1319 u64 flags; 1320 unsigned int i; 1321 int fd, ret; 1322 1323 if (copy_from_user(&ulr, ip, sizeof(ulr))) 1324 return -EFAULT; 1325 1326 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX)) 1327 return -EINVAL; 1328 1329 if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding))) 1330 return -EINVAL; 1331 1332 lc = &ulr.config; 1333 ret = gpio_v2_line_config_validate(lc, ulr.num_lines); 1334 if (ret) 1335 return ret; 1336 1337 lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL); 1338 if (!lr) 1339 return -ENOMEM; 1340 1341 lr->gdev = gdev; 1342 get_device(&gdev->dev); 1343 1344 for (i = 0; i < ulr.num_lines; i++) { 1345 lr->lines[i].req = lr; 1346 WRITE_ONCE(lr->lines[i].sw_debounced, 0); 1347 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func); 1348 } 1349 1350 if (ulr.consumer[0] != '\0') { 1351 /* label is only initialized if consumer is set */ 1352 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1, 1353 GFP_KERNEL); 1354 if (!lr->label) { 1355 ret = -ENOMEM; 1356 goto out_free_linereq; 1357 } 1358 } 1359 1360 mutex_init(&lr->config_mutex); 1361 init_waitqueue_head(&lr->wait); 1362 lr->event_buffer_size = ulr.event_buffer_size; 1363 if (lr->event_buffer_size == 0) 1364 lr->event_buffer_size = ulr.num_lines * 16; 1365 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16) 1366 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16; 1367 1368 atomic_set(&lr->seqno, 0); 1369 lr->num_lines = ulr.num_lines; 1370 1371 /* Request each GPIO */ 1372 for (i = 0; i < ulr.num_lines; i++) { 1373 u32 offset = ulr.offsets[i]; 1374 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset); 1375 1376 if (IS_ERR(desc)) { 1377 ret = PTR_ERR(desc); 1378 goto out_free_linereq; 1379 } 1380 1381 ret = gpiod_request_user(desc, lr->label); 1382 if (ret) 1383 goto out_free_linereq; 1384 1385 lr->lines[i].desc = desc; 1386 flags = gpio_v2_line_config_flags(lc, i); 1387 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1388 1389 ret = gpiod_set_transitory(desc, false); 1390 if (ret < 0) 1391 goto out_free_linereq; 1392 1393 /* 1394 * Lines have to be requested explicitly for input 1395 * or output, else the line will be treated "as is". 1396 */ 1397 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1398 int val = gpio_v2_line_config_output_value(lc, i); 1399 1400 ret = gpiod_direction_output(desc, val); 1401 if (ret) 1402 goto out_free_linereq; 1403 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1404 ret = gpiod_direction_input(desc); 1405 if (ret) 1406 goto out_free_linereq; 1407 1408 ret = edge_detector_setup(&lr->lines[i], lc, i, 1409 flags & GPIO_V2_LINE_EDGE_FLAGS); 1410 if (ret) 1411 goto out_free_linereq; 1412 } 1413 1414 blocking_notifier_call_chain(&desc->gdev->notifier, 1415 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 1416 1417 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 1418 offset); 1419 } 1420 1421 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 1422 if (fd < 0) { 1423 ret = fd; 1424 goto out_free_linereq; 1425 } 1426 1427 file = anon_inode_getfile("gpio-line", &line_fileops, lr, 1428 O_RDONLY | O_CLOEXEC); 1429 if (IS_ERR(file)) { 1430 ret = PTR_ERR(file); 1431 goto out_put_unused_fd; 1432 } 1433 1434 ulr.fd = fd; 1435 if (copy_to_user(ip, &ulr, sizeof(ulr))) { 1436 /* 1437 * fput() will trigger the release() callback, so do not go onto 1438 * the regular error cleanup path here. 1439 */ 1440 fput(file); 1441 put_unused_fd(fd); 1442 return -EFAULT; 1443 } 1444 1445 fd_install(fd, file); 1446 1447 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 1448 lr->num_lines); 1449 1450 return 0; 1451 1452 out_put_unused_fd: 1453 put_unused_fd(fd); 1454 out_free_linereq: 1455 linereq_free(lr); 1456 return ret; 1457 } 1458 1459 #ifdef CONFIG_GPIO_CDEV_V1 1460 1461 /* 1462 * GPIO line event management 1463 */ 1464 1465 /** 1466 * struct lineevent_state - contains the state of a userspace event 1467 * @gdev: the GPIO device the event pertains to 1468 * @label: consumer label used to tag descriptors 1469 * @desc: the GPIO descriptor held by this event 1470 * @eflags: the event flags this line was requested with 1471 * @irq: the interrupt that trigger in response to events on this GPIO 1472 * @wait: wait queue that handles blocking reads of events 1473 * @events: KFIFO for the GPIO events 1474 * @timestamp: cache for the timestamp storing it between hardirq 1475 * and IRQ thread, used to bring the timestamp close to the actual 1476 * event 1477 */ 1478 struct lineevent_state { 1479 struct gpio_device *gdev; 1480 const char *label; 1481 struct gpio_desc *desc; 1482 u32 eflags; 1483 int irq; 1484 wait_queue_head_t wait; 1485 DECLARE_KFIFO(events, struct gpioevent_data, 16); 1486 u64 timestamp; 1487 }; 1488 1489 #define GPIOEVENT_REQUEST_VALID_FLAGS \ 1490 (GPIOEVENT_REQUEST_RISING_EDGE | \ 1491 GPIOEVENT_REQUEST_FALLING_EDGE) 1492 1493 static __poll_t lineevent_poll(struct file *file, 1494 struct poll_table_struct *wait) 1495 { 1496 struct lineevent_state *le = file->private_data; 1497 __poll_t events = 0; 1498 1499 poll_wait(file, &le->wait, wait); 1500 1501 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock)) 1502 events = EPOLLIN | EPOLLRDNORM; 1503 1504 return events; 1505 } 1506 1507 struct compat_gpioeevent_data { 1508 compat_u64 timestamp; 1509 u32 id; 1510 }; 1511 1512 static ssize_t lineevent_read(struct file *file, 1513 char __user *buf, 1514 size_t count, 1515 loff_t *f_ps) 1516 { 1517 struct lineevent_state *le = file->private_data; 1518 struct gpioevent_data ge; 1519 ssize_t bytes_read = 0; 1520 ssize_t ge_size; 1521 int ret; 1522 1523 /* 1524 * When compatible system call is being used the struct gpioevent_data, 1525 * in case of at least ia32, has different size due to the alignment 1526 * differences. Because we have first member 64 bits followed by one of 1527 * 32 bits there is no gap between them. The only difference is the 1528 * padding at the end of the data structure. Hence, we calculate the 1529 * actual sizeof() and pass this as an argument to copy_to_user() to 1530 * drop unneeded bytes from the output. 1531 */ 1532 if (compat_need_64bit_alignment_fixup()) 1533 ge_size = sizeof(struct compat_gpioeevent_data); 1534 else 1535 ge_size = sizeof(struct gpioevent_data); 1536 if (count < ge_size) 1537 return -EINVAL; 1538 1539 do { 1540 spin_lock(&le->wait.lock); 1541 if (kfifo_is_empty(&le->events)) { 1542 if (bytes_read) { 1543 spin_unlock(&le->wait.lock); 1544 return bytes_read; 1545 } 1546 1547 if (file->f_flags & O_NONBLOCK) { 1548 spin_unlock(&le->wait.lock); 1549 return -EAGAIN; 1550 } 1551 1552 ret = wait_event_interruptible_locked(le->wait, 1553 !kfifo_is_empty(&le->events)); 1554 if (ret) { 1555 spin_unlock(&le->wait.lock); 1556 return ret; 1557 } 1558 } 1559 1560 ret = kfifo_out(&le->events, &ge, 1); 1561 spin_unlock(&le->wait.lock); 1562 if (ret != 1) { 1563 /* 1564 * This should never happen - we were holding the lock 1565 * from the moment we learned the fifo is no longer 1566 * empty until now. 1567 */ 1568 ret = -EIO; 1569 break; 1570 } 1571 1572 if (copy_to_user(buf + bytes_read, &ge, ge_size)) 1573 return -EFAULT; 1574 bytes_read += ge_size; 1575 } while (count >= bytes_read + ge_size); 1576 1577 return bytes_read; 1578 } 1579 1580 static void lineevent_free(struct lineevent_state *le) 1581 { 1582 if (le->irq) 1583 free_irq(le->irq, le); 1584 if (le->desc) 1585 gpiod_free(le->desc); 1586 kfree(le->label); 1587 put_device(&le->gdev->dev); 1588 kfree(le); 1589 } 1590 1591 static int lineevent_release(struct inode *inode, struct file *file) 1592 { 1593 lineevent_free(file->private_data); 1594 return 0; 1595 } 1596 1597 static long lineevent_ioctl(struct file *file, unsigned int cmd, 1598 unsigned long arg) 1599 { 1600 struct lineevent_state *le = file->private_data; 1601 void __user *ip = (void __user *)arg; 1602 struct gpiohandle_data ghd; 1603 1604 /* 1605 * We can get the value for an event line but not set it, 1606 * because it is input by definition. 1607 */ 1608 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { 1609 int val; 1610 1611 memset(&ghd, 0, sizeof(ghd)); 1612 1613 val = gpiod_get_value_cansleep(le->desc); 1614 if (val < 0) 1615 return val; 1616 ghd.values[0] = val; 1617 1618 if (copy_to_user(ip, &ghd, sizeof(ghd))) 1619 return -EFAULT; 1620 1621 return 0; 1622 } 1623 return -EINVAL; 1624 } 1625 1626 #ifdef CONFIG_COMPAT 1627 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd, 1628 unsigned long arg) 1629 { 1630 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1631 } 1632 #endif 1633 1634 static const struct file_operations lineevent_fileops = { 1635 .release = lineevent_release, 1636 .read = lineevent_read, 1637 .poll = lineevent_poll, 1638 .owner = THIS_MODULE, 1639 .llseek = noop_llseek, 1640 .unlocked_ioctl = lineevent_ioctl, 1641 #ifdef CONFIG_COMPAT 1642 .compat_ioctl = lineevent_ioctl_compat, 1643 #endif 1644 }; 1645 1646 static irqreturn_t lineevent_irq_thread(int irq, void *p) 1647 { 1648 struct lineevent_state *le = p; 1649 struct gpioevent_data ge; 1650 int ret; 1651 1652 /* Do not leak kernel stack to userspace */ 1653 memset(&ge, 0, sizeof(ge)); 1654 1655 /* 1656 * We may be running from a nested threaded interrupt in which case 1657 * we didn't get the timestamp from lineevent_irq_handler(). 1658 */ 1659 if (!le->timestamp) 1660 ge.timestamp = ktime_get_ns(); 1661 else 1662 ge.timestamp = le->timestamp; 1663 1664 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE 1665 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 1666 int level = gpiod_get_value_cansleep(le->desc); 1667 1668 if (level) 1669 /* Emit low-to-high event */ 1670 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 1671 else 1672 /* Emit high-to-low event */ 1673 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 1674 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) { 1675 /* Emit low-to-high event */ 1676 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 1677 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 1678 /* Emit high-to-low event */ 1679 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 1680 } else { 1681 return IRQ_NONE; 1682 } 1683 1684 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge, 1685 1, &le->wait.lock); 1686 if (ret) 1687 wake_up_poll(&le->wait, EPOLLIN); 1688 else 1689 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 1690 1691 return IRQ_HANDLED; 1692 } 1693 1694 static irqreturn_t lineevent_irq_handler(int irq, void *p) 1695 { 1696 struct lineevent_state *le = p; 1697 1698 /* 1699 * Just store the timestamp in hardirq context so we get it as 1700 * close in time as possible to the actual event. 1701 */ 1702 le->timestamp = ktime_get_ns(); 1703 1704 return IRQ_WAKE_THREAD; 1705 } 1706 1707 static int lineevent_create(struct gpio_device *gdev, void __user *ip) 1708 { 1709 struct gpioevent_request eventreq; 1710 struct lineevent_state *le; 1711 struct gpio_desc *desc; 1712 struct file *file; 1713 u32 offset; 1714 u32 lflags; 1715 u32 eflags; 1716 int fd; 1717 int ret; 1718 int irq, irqflags = 0; 1719 1720 if (copy_from_user(&eventreq, ip, sizeof(eventreq))) 1721 return -EFAULT; 1722 1723 offset = eventreq.lineoffset; 1724 lflags = eventreq.handleflags; 1725 eflags = eventreq.eventflags; 1726 1727 desc = gpiochip_get_desc(gdev->chip, offset); 1728 if (IS_ERR(desc)) 1729 return PTR_ERR(desc); 1730 1731 /* Return an error if a unknown flag is set */ 1732 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) || 1733 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS)) 1734 return -EINVAL; 1735 1736 /* This is just wrong: we don't look for events on output lines */ 1737 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) || 1738 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 1739 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 1740 return -EINVAL; 1741 1742 /* Only one bias flag can be set. */ 1743 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 1744 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 1745 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 1746 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 1747 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 1748 return -EINVAL; 1749 1750 le = kzalloc(sizeof(*le), GFP_KERNEL); 1751 if (!le) 1752 return -ENOMEM; 1753 le->gdev = gdev; 1754 get_device(&gdev->dev); 1755 1756 if (eventreq.consumer_label[0] != '\0') { 1757 /* label is only initialized if consumer_label is set */ 1758 le->label = kstrndup(eventreq.consumer_label, 1759 sizeof(eventreq.consumer_label) - 1, 1760 GFP_KERNEL); 1761 if (!le->label) { 1762 ret = -ENOMEM; 1763 goto out_free_le; 1764 } 1765 } 1766 1767 ret = gpiod_request_user(desc, le->label); 1768 if (ret) 1769 goto out_free_le; 1770 le->desc = desc; 1771 le->eflags = eflags; 1772 1773 linehandle_flags_to_desc_flags(lflags, &desc->flags); 1774 1775 ret = gpiod_direction_input(desc); 1776 if (ret) 1777 goto out_free_le; 1778 1779 blocking_notifier_call_chain(&desc->gdev->notifier, 1780 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 1781 1782 irq = gpiod_to_irq(desc); 1783 if (irq <= 0) { 1784 ret = -ENODEV; 1785 goto out_free_le; 1786 } 1787 le->irq = irq; 1788 1789 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE) 1790 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 1791 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 1792 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE) 1793 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 1794 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 1795 irqflags |= IRQF_ONESHOT; 1796 1797 INIT_KFIFO(le->events); 1798 init_waitqueue_head(&le->wait); 1799 1800 /* Request a thread to read the events */ 1801 ret = request_threaded_irq(le->irq, 1802 lineevent_irq_handler, 1803 lineevent_irq_thread, 1804 irqflags, 1805 le->label, 1806 le); 1807 if (ret) 1808 goto out_free_le; 1809 1810 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 1811 if (fd < 0) { 1812 ret = fd; 1813 goto out_free_le; 1814 } 1815 1816 file = anon_inode_getfile("gpio-event", 1817 &lineevent_fileops, 1818 le, 1819 O_RDONLY | O_CLOEXEC); 1820 if (IS_ERR(file)) { 1821 ret = PTR_ERR(file); 1822 goto out_put_unused_fd; 1823 } 1824 1825 eventreq.fd = fd; 1826 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) { 1827 /* 1828 * fput() will trigger the release() callback, so do not go onto 1829 * the regular error cleanup path here. 1830 */ 1831 fput(file); 1832 put_unused_fd(fd); 1833 return -EFAULT; 1834 } 1835 1836 fd_install(fd, file); 1837 1838 return 0; 1839 1840 out_put_unused_fd: 1841 put_unused_fd(fd); 1842 out_free_le: 1843 lineevent_free(le); 1844 return ret; 1845 } 1846 1847 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2, 1848 struct gpioline_info *info_v1) 1849 { 1850 u64 flagsv2 = info_v2->flags; 1851 1852 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name)); 1853 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer)); 1854 info_v1->line_offset = info_v2->offset; 1855 info_v1->flags = 0; 1856 1857 if (flagsv2 & GPIO_V2_LINE_FLAG_USED) 1858 info_v1->flags |= GPIOLINE_FLAG_KERNEL; 1859 1860 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT) 1861 info_v1->flags |= GPIOLINE_FLAG_IS_OUT; 1862 1863 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 1864 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW; 1865 1866 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN) 1867 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN; 1868 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE) 1869 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE; 1870 1871 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP) 1872 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP; 1873 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) 1874 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN; 1875 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED) 1876 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE; 1877 } 1878 1879 static void gpio_v2_line_info_changed_to_v1( 1880 struct gpio_v2_line_info_changed *lic_v2, 1881 struct gpioline_info_changed *lic_v1) 1882 { 1883 memset(lic_v1, 0, sizeof(*lic_v1)); 1884 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info); 1885 lic_v1->timestamp = lic_v2->timestamp_ns; 1886 lic_v1->event_type = lic_v2->event_type; 1887 } 1888 1889 #endif /* CONFIG_GPIO_CDEV_V1 */ 1890 1891 static void gpio_desc_to_lineinfo(struct gpio_desc *desc, 1892 struct gpio_v2_line_info *info) 1893 { 1894 struct gpio_chip *gc = desc->gdev->chip; 1895 bool ok_for_pinctrl; 1896 unsigned long flags; 1897 u32 debounce_period_us; 1898 unsigned int num_attrs = 0; 1899 1900 memset(info, 0, sizeof(*info)); 1901 info->offset = gpio_chip_hwgpio(desc); 1902 1903 /* 1904 * This function takes a mutex so we must check this before taking 1905 * the spinlock. 1906 * 1907 * FIXME: find a non-racy way to retrieve this information. Maybe a 1908 * lock common to both frameworks? 1909 */ 1910 ok_for_pinctrl = 1911 pinctrl_gpio_can_use_line(gc->base + info->offset); 1912 1913 spin_lock_irqsave(&gpio_lock, flags); 1914 1915 if (desc->name) 1916 strscpy(info->name, desc->name, sizeof(info->name)); 1917 1918 if (desc->label) 1919 strscpy(info->consumer, desc->label, sizeof(info->consumer)); 1920 1921 /* 1922 * Userspace only need to know that the kernel is using this GPIO so 1923 * it can't use it. 1924 */ 1925 info->flags = 0; 1926 if (test_bit(FLAG_REQUESTED, &desc->flags) || 1927 test_bit(FLAG_IS_HOGGED, &desc->flags) || 1928 test_bit(FLAG_USED_AS_IRQ, &desc->flags) || 1929 test_bit(FLAG_EXPORT, &desc->flags) || 1930 test_bit(FLAG_SYSFS, &desc->flags) || 1931 !gpiochip_line_is_valid(gc, info->offset) || 1932 !ok_for_pinctrl) 1933 info->flags |= GPIO_V2_LINE_FLAG_USED; 1934 1935 if (test_bit(FLAG_IS_OUT, &desc->flags)) 1936 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT; 1937 else 1938 info->flags |= GPIO_V2_LINE_FLAG_INPUT; 1939 1940 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) 1941 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW; 1942 1943 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) 1944 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN; 1945 if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) 1946 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE; 1947 1948 if (test_bit(FLAG_BIAS_DISABLE, &desc->flags)) 1949 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED; 1950 if (test_bit(FLAG_PULL_DOWN, &desc->flags)) 1951 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN; 1952 if (test_bit(FLAG_PULL_UP, &desc->flags)) 1953 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP; 1954 1955 if (test_bit(FLAG_EDGE_RISING, &desc->flags)) 1956 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING; 1957 if (test_bit(FLAG_EDGE_FALLING, &desc->flags)) 1958 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING; 1959 1960 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &desc->flags)) 1961 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME; 1962 1963 debounce_period_us = READ_ONCE(desc->debounce_period_us); 1964 if (debounce_period_us) { 1965 info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; 1966 info->attrs[num_attrs].debounce_period_us = debounce_period_us; 1967 num_attrs++; 1968 } 1969 info->num_attrs = num_attrs; 1970 1971 spin_unlock_irqrestore(&gpio_lock, flags); 1972 } 1973 1974 struct gpio_chardev_data { 1975 struct gpio_device *gdev; 1976 wait_queue_head_t wait; 1977 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32); 1978 struct notifier_block lineinfo_changed_nb; 1979 unsigned long *watched_lines; 1980 #ifdef CONFIG_GPIO_CDEV_V1 1981 atomic_t watch_abi_version; 1982 #endif 1983 }; 1984 1985 static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip) 1986 { 1987 struct gpio_device *gdev = cdev->gdev; 1988 struct gpiochip_info chipinfo; 1989 1990 memset(&chipinfo, 0, sizeof(chipinfo)); 1991 1992 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name)); 1993 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label)); 1994 chipinfo.lines = gdev->ngpio; 1995 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo))) 1996 return -EFAULT; 1997 return 0; 1998 } 1999 2000 #ifdef CONFIG_GPIO_CDEV_V1 2001 /* 2002 * returns 0 if the versions match, else the previously selected ABI version 2003 */ 2004 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata, 2005 unsigned int version) 2006 { 2007 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version); 2008 2009 if (abiv == version) 2010 return 0; 2011 2012 return abiv; 2013 } 2014 2015 static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip, 2016 bool watch) 2017 { 2018 struct gpio_desc *desc; 2019 struct gpioline_info lineinfo; 2020 struct gpio_v2_line_info lineinfo_v2; 2021 2022 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2023 return -EFAULT; 2024 2025 /* this doubles as a range check on line_offset */ 2026 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset); 2027 if (IS_ERR(desc)) 2028 return PTR_ERR(desc); 2029 2030 if (watch) { 2031 if (lineinfo_ensure_abi_version(cdev, 1)) 2032 return -EPERM; 2033 2034 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines)) 2035 return -EBUSY; 2036 } 2037 2038 gpio_desc_to_lineinfo(desc, &lineinfo_v2); 2039 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); 2040 2041 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2042 if (watch) 2043 clear_bit(lineinfo.line_offset, cdev->watched_lines); 2044 return -EFAULT; 2045 } 2046 2047 return 0; 2048 } 2049 #endif 2050 2051 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, 2052 bool watch) 2053 { 2054 struct gpio_desc *desc; 2055 struct gpio_v2_line_info lineinfo; 2056 2057 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2058 return -EFAULT; 2059 2060 if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding))) 2061 return -EINVAL; 2062 2063 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset); 2064 if (IS_ERR(desc)) 2065 return PTR_ERR(desc); 2066 2067 if (watch) { 2068 #ifdef CONFIG_GPIO_CDEV_V1 2069 if (lineinfo_ensure_abi_version(cdev, 2)) 2070 return -EPERM; 2071 #endif 2072 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines)) 2073 return -EBUSY; 2074 } 2075 gpio_desc_to_lineinfo(desc, &lineinfo); 2076 2077 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2078 if (watch) 2079 clear_bit(lineinfo.offset, cdev->watched_lines); 2080 return -EFAULT; 2081 } 2082 2083 return 0; 2084 } 2085 2086 static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip) 2087 { 2088 __u32 offset; 2089 2090 if (copy_from_user(&offset, ip, sizeof(offset))) 2091 return -EFAULT; 2092 2093 if (offset >= cdev->gdev->ngpio) 2094 return -EINVAL; 2095 2096 if (!test_and_clear_bit(offset, cdev->watched_lines)) 2097 return -EBUSY; 2098 2099 return 0; 2100 } 2101 2102 /* 2103 * gpio_ioctl() - ioctl handler for the GPIO chardev 2104 */ 2105 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 2106 { 2107 struct gpio_chardev_data *cdev = file->private_data; 2108 struct gpio_device *gdev = cdev->gdev; 2109 void __user *ip = (void __user *)arg; 2110 2111 /* We fail any subsequent ioctl():s when the chip is gone */ 2112 if (!gdev->chip) 2113 return -ENODEV; 2114 2115 /* Fill in the struct and pass to userspace */ 2116 if (cmd == GPIO_GET_CHIPINFO_IOCTL) { 2117 return chipinfo_get(cdev, ip); 2118 #ifdef CONFIG_GPIO_CDEV_V1 2119 } else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) { 2120 return linehandle_create(gdev, ip); 2121 } else if (cmd == GPIO_GET_LINEEVENT_IOCTL) { 2122 return lineevent_create(gdev, ip); 2123 } else if (cmd == GPIO_GET_LINEINFO_IOCTL || 2124 cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) { 2125 return lineinfo_get_v1(cdev, ip, 2126 cmd == GPIO_GET_LINEINFO_WATCH_IOCTL); 2127 #endif /* CONFIG_GPIO_CDEV_V1 */ 2128 } else if (cmd == GPIO_V2_GET_LINEINFO_IOCTL || 2129 cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL) { 2130 return lineinfo_get(cdev, ip, 2131 cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL); 2132 } else if (cmd == GPIO_V2_GET_LINE_IOCTL) { 2133 return linereq_create(gdev, ip); 2134 } else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) { 2135 return lineinfo_unwatch(cdev, ip); 2136 } 2137 return -EINVAL; 2138 } 2139 2140 #ifdef CONFIG_COMPAT 2141 static long gpio_ioctl_compat(struct file *file, unsigned int cmd, 2142 unsigned long arg) 2143 { 2144 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 2145 } 2146 #endif 2147 2148 static struct gpio_chardev_data * 2149 to_gpio_chardev_data(struct notifier_block *nb) 2150 { 2151 return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb); 2152 } 2153 2154 static int lineinfo_changed_notify(struct notifier_block *nb, 2155 unsigned long action, void *data) 2156 { 2157 struct gpio_chardev_data *cdev = to_gpio_chardev_data(nb); 2158 struct gpio_v2_line_info_changed chg; 2159 struct gpio_desc *desc = data; 2160 int ret; 2161 2162 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines)) 2163 return NOTIFY_DONE; 2164 2165 memset(&chg, 0, sizeof(chg)); 2166 chg.event_type = action; 2167 chg.timestamp_ns = ktime_get_ns(); 2168 gpio_desc_to_lineinfo(desc, &chg.info); 2169 2170 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock); 2171 if (ret) 2172 wake_up_poll(&cdev->wait, EPOLLIN); 2173 else 2174 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n"); 2175 2176 return NOTIFY_OK; 2177 } 2178 2179 static __poll_t lineinfo_watch_poll(struct file *file, 2180 struct poll_table_struct *pollt) 2181 { 2182 struct gpio_chardev_data *cdev = file->private_data; 2183 __poll_t events = 0; 2184 2185 poll_wait(file, &cdev->wait, pollt); 2186 2187 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events, 2188 &cdev->wait.lock)) 2189 events = EPOLLIN | EPOLLRDNORM; 2190 2191 return events; 2192 } 2193 2194 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, 2195 size_t count, loff_t *off) 2196 { 2197 struct gpio_chardev_data *cdev = file->private_data; 2198 struct gpio_v2_line_info_changed event; 2199 ssize_t bytes_read = 0; 2200 int ret; 2201 size_t event_size; 2202 2203 #ifndef CONFIG_GPIO_CDEV_V1 2204 event_size = sizeof(struct gpio_v2_line_info_changed); 2205 if (count < event_size) 2206 return -EINVAL; 2207 #endif 2208 2209 do { 2210 spin_lock(&cdev->wait.lock); 2211 if (kfifo_is_empty(&cdev->events)) { 2212 if (bytes_read) { 2213 spin_unlock(&cdev->wait.lock); 2214 return bytes_read; 2215 } 2216 2217 if (file->f_flags & O_NONBLOCK) { 2218 spin_unlock(&cdev->wait.lock); 2219 return -EAGAIN; 2220 } 2221 2222 ret = wait_event_interruptible_locked(cdev->wait, 2223 !kfifo_is_empty(&cdev->events)); 2224 if (ret) { 2225 spin_unlock(&cdev->wait.lock); 2226 return ret; 2227 } 2228 } 2229 #ifdef CONFIG_GPIO_CDEV_V1 2230 /* must be after kfifo check so watch_abi_version is set */ 2231 if (atomic_read(&cdev->watch_abi_version) == 2) 2232 event_size = sizeof(struct gpio_v2_line_info_changed); 2233 else 2234 event_size = sizeof(struct gpioline_info_changed); 2235 if (count < event_size) { 2236 spin_unlock(&cdev->wait.lock); 2237 return -EINVAL; 2238 } 2239 #endif 2240 ret = kfifo_out(&cdev->events, &event, 1); 2241 spin_unlock(&cdev->wait.lock); 2242 if (ret != 1) { 2243 ret = -EIO; 2244 break; 2245 /* We should never get here. See lineevent_read(). */ 2246 } 2247 2248 #ifdef CONFIG_GPIO_CDEV_V1 2249 if (event_size == sizeof(struct gpio_v2_line_info_changed)) { 2250 if (copy_to_user(buf + bytes_read, &event, event_size)) 2251 return -EFAULT; 2252 } else { 2253 struct gpioline_info_changed event_v1; 2254 2255 gpio_v2_line_info_changed_to_v1(&event, &event_v1); 2256 if (copy_to_user(buf + bytes_read, &event_v1, 2257 event_size)) 2258 return -EFAULT; 2259 } 2260 #else 2261 if (copy_to_user(buf + bytes_read, &event, event_size)) 2262 return -EFAULT; 2263 #endif 2264 bytes_read += event_size; 2265 } while (count >= bytes_read + sizeof(event)); 2266 2267 return bytes_read; 2268 } 2269 2270 /** 2271 * gpio_chrdev_open() - open the chardev for ioctl operations 2272 * @inode: inode for this chardev 2273 * @file: file struct for storing private data 2274 * Returns 0 on success 2275 */ 2276 static int gpio_chrdev_open(struct inode *inode, struct file *file) 2277 { 2278 struct gpio_device *gdev = container_of(inode->i_cdev, 2279 struct gpio_device, chrdev); 2280 struct gpio_chardev_data *cdev; 2281 int ret = -ENOMEM; 2282 2283 /* Fail on open if the backing gpiochip is gone */ 2284 if (!gdev->chip) 2285 return -ENODEV; 2286 2287 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL); 2288 if (!cdev) 2289 return -ENOMEM; 2290 2291 cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL); 2292 if (!cdev->watched_lines) 2293 goto out_free_cdev; 2294 2295 init_waitqueue_head(&cdev->wait); 2296 INIT_KFIFO(cdev->events); 2297 cdev->gdev = gdev; 2298 2299 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify; 2300 ret = blocking_notifier_chain_register(&gdev->notifier, 2301 &cdev->lineinfo_changed_nb); 2302 if (ret) 2303 goto out_free_bitmap; 2304 2305 get_device(&gdev->dev); 2306 file->private_data = cdev; 2307 2308 ret = nonseekable_open(inode, file); 2309 if (ret) 2310 goto out_unregister_notifier; 2311 2312 return ret; 2313 2314 out_unregister_notifier: 2315 blocking_notifier_chain_unregister(&gdev->notifier, 2316 &cdev->lineinfo_changed_nb); 2317 out_free_bitmap: 2318 bitmap_free(cdev->watched_lines); 2319 out_free_cdev: 2320 kfree(cdev); 2321 return ret; 2322 } 2323 2324 /** 2325 * gpio_chrdev_release() - close chardev after ioctl operations 2326 * @inode: inode for this chardev 2327 * @file: file struct for storing private data 2328 * Returns 0 on success 2329 */ 2330 static int gpio_chrdev_release(struct inode *inode, struct file *file) 2331 { 2332 struct gpio_chardev_data *cdev = file->private_data; 2333 struct gpio_device *gdev = cdev->gdev; 2334 2335 bitmap_free(cdev->watched_lines); 2336 blocking_notifier_chain_unregister(&gdev->notifier, 2337 &cdev->lineinfo_changed_nb); 2338 put_device(&gdev->dev); 2339 kfree(cdev); 2340 2341 return 0; 2342 } 2343 2344 static const struct file_operations gpio_fileops = { 2345 .release = gpio_chrdev_release, 2346 .open = gpio_chrdev_open, 2347 .poll = lineinfo_watch_poll, 2348 .read = lineinfo_watch_read, 2349 .owner = THIS_MODULE, 2350 .llseek = no_llseek, 2351 .unlocked_ioctl = gpio_ioctl, 2352 #ifdef CONFIG_COMPAT 2353 .compat_ioctl = gpio_ioctl_compat, 2354 #endif 2355 }; 2356 2357 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt) 2358 { 2359 int ret; 2360 2361 cdev_init(&gdev->chrdev, &gpio_fileops); 2362 gdev->chrdev.owner = THIS_MODULE; 2363 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id); 2364 2365 ret = cdev_device_add(&gdev->chrdev, &gdev->dev); 2366 if (ret) 2367 return ret; 2368 2369 chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n", 2370 MAJOR(devt), gdev->id); 2371 2372 return 0; 2373 } 2374 2375 void gpiolib_cdev_unregister(struct gpio_device *gdev) 2376 { 2377 cdev_device_del(&gdev->chrdev, &gdev->dev); 2378 } 2379