1 // SPDX-License-Identifier: GPL-2.0 2 3 #include <linux/anon_inodes.h> 4 #include <linux/atomic.h> 5 #include <linux/bitmap.h> 6 #include <linux/build_bug.h> 7 #include <linux/cdev.h> 8 #include <linux/compat.h> 9 #include <linux/compiler.h> 10 #include <linux/device.h> 11 #include <linux/err.h> 12 #include <linux/file.h> 13 #include <linux/gpio.h> 14 #include <linux/gpio/driver.h> 15 #include <linux/interrupt.h> 16 #include <linux/irqreturn.h> 17 #include <linux/kernel.h> 18 #include <linux/kfifo.h> 19 #include <linux/module.h> 20 #include <linux/mutex.h> 21 #include <linux/pinctrl/consumer.h> 22 #include <linux/poll.h> 23 #include <linux/spinlock.h> 24 #include <linux/timekeeping.h> 25 #include <linux/uaccess.h> 26 #include <linux/workqueue.h> 27 #include <uapi/linux/gpio.h> 28 29 #include "gpiolib.h" 30 #include "gpiolib-cdev.h" 31 32 /* 33 * Array sizes must ensure 64-bit alignment and not create holes in the 34 * struct packing. 35 */ 36 static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2)); 37 static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8)); 38 39 /* 40 * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility 41 */ 42 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8)); 43 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8)); 44 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8)); 45 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8)); 46 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8)); 47 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8)); 48 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8)); 49 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8)); 50 51 /* Character device interface to GPIO. 52 * 53 * The GPIO character device, /dev/gpiochipN, provides userspace an 54 * interface to gpiolib GPIOs via ioctl()s. 55 */ 56 57 /* 58 * GPIO line handle management 59 */ 60 61 #ifdef CONFIG_GPIO_CDEV_V1 62 /** 63 * struct linehandle_state - contains the state of a userspace handle 64 * @gdev: the GPIO device the handle pertains to 65 * @label: consumer label used to tag descriptors 66 * @descs: the GPIO descriptors held by this handle 67 * @num_descs: the number of descriptors held in the descs array 68 */ 69 struct linehandle_state { 70 struct gpio_device *gdev; 71 const char *label; 72 struct gpio_desc *descs[GPIOHANDLES_MAX]; 73 u32 num_descs; 74 }; 75 76 #define GPIOHANDLE_REQUEST_VALID_FLAGS \ 77 (GPIOHANDLE_REQUEST_INPUT | \ 78 GPIOHANDLE_REQUEST_OUTPUT | \ 79 GPIOHANDLE_REQUEST_ACTIVE_LOW | \ 80 GPIOHANDLE_REQUEST_BIAS_PULL_UP | \ 81 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \ 82 GPIOHANDLE_REQUEST_BIAS_DISABLE | \ 83 GPIOHANDLE_REQUEST_OPEN_DRAIN | \ 84 GPIOHANDLE_REQUEST_OPEN_SOURCE) 85 86 static int linehandle_validate_flags(u32 flags) 87 { 88 /* Return an error if an unknown flag is set */ 89 if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) 90 return -EINVAL; 91 92 /* 93 * Do not allow both INPUT & OUTPUT flags to be set as they are 94 * contradictory. 95 */ 96 if ((flags & GPIOHANDLE_REQUEST_INPUT) && 97 (flags & GPIOHANDLE_REQUEST_OUTPUT)) 98 return -EINVAL; 99 100 /* 101 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If 102 * the hardware actually supports enabling both at the same time the 103 * electrical result would be disastrous. 104 */ 105 if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) && 106 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 107 return -EINVAL; 108 109 /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */ 110 if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) && 111 ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 112 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))) 113 return -EINVAL; 114 115 /* Bias flags only allowed for input or output mode. */ 116 if (!((flags & GPIOHANDLE_REQUEST_INPUT) || 117 (flags & GPIOHANDLE_REQUEST_OUTPUT)) && 118 ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) || 119 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) || 120 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN))) 121 return -EINVAL; 122 123 /* Only one bias flag can be set. */ 124 if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 125 (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 126 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 127 ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 128 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 129 return -EINVAL; 130 131 return 0; 132 } 133 134 static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp) 135 { 136 assign_bit(FLAG_ACTIVE_LOW, flagsp, 137 lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW); 138 assign_bit(FLAG_OPEN_DRAIN, flagsp, 139 lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN); 140 assign_bit(FLAG_OPEN_SOURCE, flagsp, 141 lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE); 142 assign_bit(FLAG_PULL_UP, flagsp, 143 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP); 144 assign_bit(FLAG_PULL_DOWN, flagsp, 145 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN); 146 assign_bit(FLAG_BIAS_DISABLE, flagsp, 147 lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE); 148 } 149 150 static long linehandle_set_config(struct linehandle_state *lh, 151 void __user *ip) 152 { 153 struct gpiohandle_config gcnf; 154 struct gpio_desc *desc; 155 int i, ret; 156 u32 lflags; 157 158 if (copy_from_user(&gcnf, ip, sizeof(gcnf))) 159 return -EFAULT; 160 161 lflags = gcnf.flags; 162 ret = linehandle_validate_flags(lflags); 163 if (ret) 164 return ret; 165 166 for (i = 0; i < lh->num_descs; i++) { 167 desc = lh->descs[i]; 168 linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags); 169 170 /* 171 * Lines have to be requested explicitly for input 172 * or output, else the line will be treated "as is". 173 */ 174 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { 175 int val = !!gcnf.default_values[i]; 176 177 ret = gpiod_direction_output(desc, val); 178 if (ret) 179 return ret; 180 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { 181 ret = gpiod_direction_input(desc); 182 if (ret) 183 return ret; 184 } 185 186 blocking_notifier_call_chain(&desc->gdev->notifier, 187 GPIO_V2_LINE_CHANGED_CONFIG, 188 desc); 189 } 190 return 0; 191 } 192 193 static long linehandle_ioctl(struct file *file, unsigned int cmd, 194 unsigned long arg) 195 { 196 struct linehandle_state *lh = file->private_data; 197 void __user *ip = (void __user *)arg; 198 struct gpiohandle_data ghd; 199 DECLARE_BITMAP(vals, GPIOHANDLES_MAX); 200 int i; 201 202 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { 203 /* NOTE: It's ok to read values of output lines. */ 204 int ret = gpiod_get_array_value_complex(false, 205 true, 206 lh->num_descs, 207 lh->descs, 208 NULL, 209 vals); 210 if (ret) 211 return ret; 212 213 memset(&ghd, 0, sizeof(ghd)); 214 for (i = 0; i < lh->num_descs; i++) 215 ghd.values[i] = test_bit(i, vals); 216 217 if (copy_to_user(ip, &ghd, sizeof(ghd))) 218 return -EFAULT; 219 220 return 0; 221 } else if (cmd == GPIOHANDLE_SET_LINE_VALUES_IOCTL) { 222 /* 223 * All line descriptors were created at once with the same 224 * flags so just check if the first one is really output. 225 */ 226 if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags)) 227 return -EPERM; 228 229 if (copy_from_user(&ghd, ip, sizeof(ghd))) 230 return -EFAULT; 231 232 /* Clamp all values to [0,1] */ 233 for (i = 0; i < lh->num_descs; i++) 234 __assign_bit(i, vals, ghd.values[i]); 235 236 /* Reuse the array setting function */ 237 return gpiod_set_array_value_complex(false, 238 true, 239 lh->num_descs, 240 lh->descs, 241 NULL, 242 vals); 243 } else if (cmd == GPIOHANDLE_SET_CONFIG_IOCTL) { 244 return linehandle_set_config(lh, ip); 245 } 246 return -EINVAL; 247 } 248 249 #ifdef CONFIG_COMPAT 250 static long linehandle_ioctl_compat(struct file *file, unsigned int cmd, 251 unsigned long arg) 252 { 253 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 254 } 255 #endif 256 257 static void linehandle_free(struct linehandle_state *lh) 258 { 259 int i; 260 261 for (i = 0; i < lh->num_descs; i++) 262 if (lh->descs[i]) 263 gpiod_free(lh->descs[i]); 264 kfree(lh->label); 265 put_device(&lh->gdev->dev); 266 kfree(lh); 267 } 268 269 static int linehandle_release(struct inode *inode, struct file *file) 270 { 271 linehandle_free(file->private_data); 272 return 0; 273 } 274 275 static const struct file_operations linehandle_fileops = { 276 .release = linehandle_release, 277 .owner = THIS_MODULE, 278 .llseek = noop_llseek, 279 .unlocked_ioctl = linehandle_ioctl, 280 #ifdef CONFIG_COMPAT 281 .compat_ioctl = linehandle_ioctl_compat, 282 #endif 283 }; 284 285 static int linehandle_create(struct gpio_device *gdev, void __user *ip) 286 { 287 struct gpiohandle_request handlereq; 288 struct linehandle_state *lh; 289 struct file *file; 290 int fd, i, ret; 291 u32 lflags; 292 293 if (copy_from_user(&handlereq, ip, sizeof(handlereq))) 294 return -EFAULT; 295 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX)) 296 return -EINVAL; 297 298 lflags = handlereq.flags; 299 300 ret = linehandle_validate_flags(lflags); 301 if (ret) 302 return ret; 303 304 lh = kzalloc(sizeof(*lh), GFP_KERNEL); 305 if (!lh) 306 return -ENOMEM; 307 lh->gdev = gdev; 308 get_device(&gdev->dev); 309 310 if (handlereq.consumer_label[0] != '\0') { 311 /* label is only initialized if consumer_label is set */ 312 lh->label = kstrndup(handlereq.consumer_label, 313 sizeof(handlereq.consumer_label) - 1, 314 GFP_KERNEL); 315 if (!lh->label) { 316 ret = -ENOMEM; 317 goto out_free_lh; 318 } 319 } 320 321 lh->num_descs = handlereq.lines; 322 323 /* Request each GPIO */ 324 for (i = 0; i < handlereq.lines; i++) { 325 u32 offset = handlereq.lineoffsets[i]; 326 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset); 327 328 if (IS_ERR(desc)) { 329 ret = PTR_ERR(desc); 330 goto out_free_lh; 331 } 332 333 ret = gpiod_request(desc, lh->label); 334 if (ret) 335 goto out_free_lh; 336 lh->descs[i] = desc; 337 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags); 338 339 ret = gpiod_set_transitory(desc, false); 340 if (ret < 0) 341 goto out_free_lh; 342 343 /* 344 * Lines have to be requested explicitly for input 345 * or output, else the line will be treated "as is". 346 */ 347 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { 348 int val = !!handlereq.default_values[i]; 349 350 ret = gpiod_direction_output(desc, val); 351 if (ret) 352 goto out_free_lh; 353 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { 354 ret = gpiod_direction_input(desc); 355 if (ret) 356 goto out_free_lh; 357 } 358 359 blocking_notifier_call_chain(&desc->gdev->notifier, 360 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 361 362 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 363 offset); 364 } 365 366 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 367 if (fd < 0) { 368 ret = fd; 369 goto out_free_lh; 370 } 371 372 file = anon_inode_getfile("gpio-linehandle", 373 &linehandle_fileops, 374 lh, 375 O_RDONLY | O_CLOEXEC); 376 if (IS_ERR(file)) { 377 ret = PTR_ERR(file); 378 goto out_put_unused_fd; 379 } 380 381 handlereq.fd = fd; 382 if (copy_to_user(ip, &handlereq, sizeof(handlereq))) { 383 /* 384 * fput() will trigger the release() callback, so do not go onto 385 * the regular error cleanup path here. 386 */ 387 fput(file); 388 put_unused_fd(fd); 389 return -EFAULT; 390 } 391 392 fd_install(fd, file); 393 394 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 395 lh->num_descs); 396 397 return 0; 398 399 out_put_unused_fd: 400 put_unused_fd(fd); 401 out_free_lh: 402 linehandle_free(lh); 403 return ret; 404 } 405 #endif /* CONFIG_GPIO_CDEV_V1 */ 406 407 /** 408 * struct line - contains the state of a requested line 409 * @desc: the GPIO descriptor for this line. 410 * @req: the corresponding line request 411 * @irq: the interrupt triggered in response to events on this GPIO 412 * @eflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or 413 * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied 414 * @timestamp_ns: cache for the timestamp storing it between hardirq and 415 * IRQ thread, used to bring the timestamp close to the actual event 416 * @req_seqno: the seqno for the current edge event in the sequence of 417 * events for the corresponding line request. This is drawn from the @req. 418 * @line_seqno: the seqno for the current edge event in the sequence of 419 * events for this line. 420 * @work: the worker that implements software debouncing 421 * @sw_debounced: flag indicating if the software debouncer is active 422 * @level: the current debounced physical level of the line 423 */ 424 struct line { 425 struct gpio_desc *desc; 426 /* 427 * -- edge detector specific fields -- 428 */ 429 struct linereq *req; 430 unsigned int irq; 431 u64 eflags; 432 /* 433 * timestamp_ns and req_seqno are accessed only by 434 * edge_irq_handler() and edge_irq_thread(), which are themselves 435 * mutually exclusive, so no additional protection is necessary. 436 */ 437 u64 timestamp_ns; 438 u32 req_seqno; 439 /* 440 * line_seqno is accessed by either edge_irq_thread() or 441 * debounce_work_func(), which are themselves mutually exclusive, 442 * so no additional protection is necessary. 443 */ 444 u32 line_seqno; 445 /* 446 * -- debouncer specific fields -- 447 */ 448 struct delayed_work work; 449 /* 450 * sw_debounce is accessed by linereq_set_config(), which is the 451 * only setter, and linereq_get_values(), which can live with a 452 * slightly stale value. 453 */ 454 unsigned int sw_debounced; 455 /* 456 * level is accessed by debounce_work_func(), which is the only 457 * setter, and linereq_get_values() which can live with a slightly 458 * stale value. 459 */ 460 unsigned int level; 461 }; 462 463 /** 464 * struct linereq - contains the state of a userspace line request 465 * @gdev: the GPIO device the line request pertains to 466 * @label: consumer label used to tag GPIO descriptors 467 * @num_lines: the number of lines in the lines array 468 * @wait: wait queue that handles blocking reads of events 469 * @event_buffer_size: the number of elements allocated in @events 470 * @events: KFIFO for the GPIO events 471 * @seqno: the sequence number for edge events generated on all lines in 472 * this line request. Note that this is not used when @num_lines is 1, as 473 * the line_seqno is then the same and is cheaper to calculate. 474 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency 475 * of configuration, particularly multi-step accesses to desc flags. 476 * @lines: the lines held by this line request, with @num_lines elements. 477 */ 478 struct linereq { 479 struct gpio_device *gdev; 480 const char *label; 481 u32 num_lines; 482 wait_queue_head_t wait; 483 u32 event_buffer_size; 484 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event); 485 atomic_t seqno; 486 struct mutex config_mutex; 487 struct line lines[]; 488 }; 489 490 #define GPIO_V2_LINE_BIAS_FLAGS \ 491 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \ 492 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \ 493 GPIO_V2_LINE_FLAG_BIAS_DISABLED) 494 495 #define GPIO_V2_LINE_DIRECTION_FLAGS \ 496 (GPIO_V2_LINE_FLAG_INPUT | \ 497 GPIO_V2_LINE_FLAG_OUTPUT) 498 499 #define GPIO_V2_LINE_DRIVE_FLAGS \ 500 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \ 501 GPIO_V2_LINE_FLAG_OPEN_SOURCE) 502 503 #define GPIO_V2_LINE_EDGE_FLAGS \ 504 (GPIO_V2_LINE_FLAG_EDGE_RISING | \ 505 GPIO_V2_LINE_FLAG_EDGE_FALLING) 506 507 #define GPIO_V2_LINE_VALID_FLAGS \ 508 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ 509 GPIO_V2_LINE_DIRECTION_FLAGS | \ 510 GPIO_V2_LINE_DRIVE_FLAGS | \ 511 GPIO_V2_LINE_EDGE_FLAGS | \ 512 GPIO_V2_LINE_BIAS_FLAGS) 513 514 static void linereq_put_event(struct linereq *lr, 515 struct gpio_v2_line_event *le) 516 { 517 bool overflow = false; 518 519 spin_lock(&lr->wait.lock); 520 if (kfifo_is_full(&lr->events)) { 521 overflow = true; 522 kfifo_skip(&lr->events); 523 } 524 kfifo_in(&lr->events, le, 1); 525 spin_unlock(&lr->wait.lock); 526 if (!overflow) 527 wake_up_poll(&lr->wait, EPOLLIN); 528 else 529 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 530 } 531 532 static irqreturn_t edge_irq_thread(int irq, void *p) 533 { 534 struct line *line = p; 535 struct linereq *lr = line->req; 536 struct gpio_v2_line_event le; 537 538 /* Do not leak kernel stack to userspace */ 539 memset(&le, 0, sizeof(le)); 540 541 if (line->timestamp_ns) { 542 le.timestamp_ns = line->timestamp_ns; 543 } else { 544 /* 545 * We may be running from a nested threaded interrupt in 546 * which case we didn't get the timestamp from 547 * edge_irq_handler(). 548 */ 549 le.timestamp_ns = ktime_get_ns(); 550 if (lr->num_lines != 1) 551 line->req_seqno = atomic_inc_return(&lr->seqno); 552 } 553 line->timestamp_ns = 0; 554 555 if (line->eflags == (GPIO_V2_LINE_FLAG_EDGE_RISING | 556 GPIO_V2_LINE_FLAG_EDGE_FALLING)) { 557 int level = gpiod_get_value_cansleep(line->desc); 558 559 if (level) 560 /* Emit low-to-high event */ 561 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 562 else 563 /* Emit high-to-low event */ 564 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 565 } else if (line->eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) { 566 /* Emit low-to-high event */ 567 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 568 } else if (line->eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) { 569 /* Emit high-to-low event */ 570 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 571 } else { 572 return IRQ_NONE; 573 } 574 line->line_seqno++; 575 le.line_seqno = line->line_seqno; 576 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno; 577 le.offset = gpio_chip_hwgpio(line->desc); 578 579 linereq_put_event(lr, &le); 580 581 return IRQ_HANDLED; 582 } 583 584 static irqreturn_t edge_irq_handler(int irq, void *p) 585 { 586 struct line *line = p; 587 struct linereq *lr = line->req; 588 589 /* 590 * Just store the timestamp in hardirq context so we get it as 591 * close in time as possible to the actual event. 592 */ 593 line->timestamp_ns = ktime_get_ns(); 594 595 if (lr->num_lines != 1) 596 line->req_seqno = atomic_inc_return(&lr->seqno); 597 598 return IRQ_WAKE_THREAD; 599 } 600 601 /* 602 * returns the current debounced logical value. 603 */ 604 static bool debounced_value(struct line *line) 605 { 606 bool value; 607 608 /* 609 * minor race - debouncer may be stopped here, so edge_detector_stop() 610 * must leave the value unchanged so the following will read the level 611 * from when the debouncer was last running. 612 */ 613 value = READ_ONCE(line->level); 614 615 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags)) 616 value = !value; 617 618 return value; 619 } 620 621 static irqreturn_t debounce_irq_handler(int irq, void *p) 622 { 623 struct line *line = p; 624 625 mod_delayed_work(system_wq, &line->work, 626 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); 627 628 return IRQ_HANDLED; 629 } 630 631 static void debounce_work_func(struct work_struct *work) 632 { 633 struct gpio_v2_line_event le; 634 struct line *line = container_of(work, struct line, work.work); 635 struct linereq *lr; 636 int level; 637 638 level = gpiod_get_raw_value_cansleep(line->desc); 639 if (level < 0) { 640 pr_debug_ratelimited("debouncer failed to read line value\n"); 641 return; 642 } 643 644 if (READ_ONCE(line->level) == level) 645 return; 646 647 WRITE_ONCE(line->level, level); 648 649 /* -- edge detection -- */ 650 if (!line->eflags) 651 return; 652 653 /* switch from physical level to logical - if they differ */ 654 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags)) 655 level = !level; 656 657 /* ignore edges that are not being monitored */ 658 if (((line->eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) || 659 ((line->eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level)) 660 return; 661 662 /* Do not leak kernel stack to userspace */ 663 memset(&le, 0, sizeof(le)); 664 665 lr = line->req; 666 le.timestamp_ns = ktime_get_ns(); 667 le.offset = gpio_chip_hwgpio(line->desc); 668 line->line_seqno++; 669 le.line_seqno = line->line_seqno; 670 le.seqno = (lr->num_lines == 1) ? 671 le.line_seqno : atomic_inc_return(&lr->seqno); 672 673 if (level) 674 /* Emit low-to-high event */ 675 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 676 else 677 /* Emit high-to-low event */ 678 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 679 680 linereq_put_event(lr, &le); 681 } 682 683 static int debounce_setup(struct line *line, 684 unsigned int debounce_period_us) 685 { 686 unsigned long irqflags; 687 int ret, level, irq; 688 689 /* try hardware */ 690 ret = gpiod_set_debounce(line->desc, debounce_period_us); 691 if (!ret) { 692 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 693 return ret; 694 } 695 if (ret != -ENOTSUPP) 696 return ret; 697 698 if (debounce_period_us) { 699 /* setup software debounce */ 700 level = gpiod_get_raw_value_cansleep(line->desc); 701 if (level < 0) 702 return level; 703 704 irq = gpiod_to_irq(line->desc); 705 if (irq < 0) 706 return -ENXIO; 707 708 WRITE_ONCE(line->level, level); 709 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING; 710 ret = request_irq(irq, debounce_irq_handler, irqflags, 711 line->req->label, line); 712 if (ret) 713 return ret; 714 715 WRITE_ONCE(line->sw_debounced, 1); 716 line->irq = irq; 717 } 718 return 0; 719 } 720 721 static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc, 722 unsigned int line_idx) 723 { 724 unsigned int i; 725 u64 mask = BIT_ULL(line_idx); 726 727 for (i = 0; i < lc->num_attrs; i++) { 728 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 729 (lc->attrs[i].mask & mask)) 730 return true; 731 } 732 return false; 733 } 734 735 static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc, 736 unsigned int line_idx) 737 { 738 unsigned int i; 739 u64 mask = BIT_ULL(line_idx); 740 741 for (i = 0; i < lc->num_attrs; i++) { 742 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 743 (lc->attrs[i].mask & mask)) 744 return lc->attrs[i].attr.debounce_period_us; 745 } 746 return 0; 747 } 748 749 static void edge_detector_stop(struct line *line) 750 { 751 if (line->irq) { 752 free_irq(line->irq, line); 753 line->irq = 0; 754 } 755 756 cancel_delayed_work_sync(&line->work); 757 WRITE_ONCE(line->sw_debounced, 0); 758 line->eflags = 0; 759 /* do not change line->level - see comment in debounced_value() */ 760 } 761 762 static int edge_detector_setup(struct line *line, 763 struct gpio_v2_line_config *lc, 764 unsigned int line_idx, 765 u64 eflags) 766 { 767 u32 debounce_period_us; 768 unsigned long irqflags = 0; 769 int irq, ret; 770 771 if (eflags && !kfifo_initialized(&line->req->events)) { 772 ret = kfifo_alloc(&line->req->events, 773 line->req->event_buffer_size, GFP_KERNEL); 774 if (ret) 775 return ret; 776 } 777 line->eflags = eflags; 778 if (gpio_v2_line_config_debounced(lc, line_idx)) { 779 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx); 780 ret = debounce_setup(line, debounce_period_us); 781 if (ret) 782 return ret; 783 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 784 } 785 786 /* detection disabled or sw debouncer will provide edge detection */ 787 if (!eflags || READ_ONCE(line->sw_debounced)) 788 return 0; 789 790 irq = gpiod_to_irq(line->desc); 791 if (irq < 0) 792 return -ENXIO; 793 794 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING) 795 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 796 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 797 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING) 798 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 799 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 800 irqflags |= IRQF_ONESHOT; 801 802 /* Request a thread to read the events */ 803 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread, 804 irqflags, line->req->label, line); 805 if (ret) 806 return ret; 807 808 line->irq = irq; 809 return 0; 810 } 811 812 static int edge_detector_update(struct line *line, 813 struct gpio_v2_line_config *lc, 814 unsigned int line_idx, 815 u64 eflags, bool polarity_change) 816 { 817 unsigned int debounce_period_us = 818 gpio_v2_line_config_debounce_period(lc, line_idx); 819 820 if ((line->eflags == eflags) && !polarity_change && 821 (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us)) 822 return 0; 823 824 /* sw debounced and still will be...*/ 825 if (debounce_period_us && READ_ONCE(line->sw_debounced)) { 826 line->eflags = eflags; 827 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 828 return 0; 829 } 830 831 /* reconfiguring edge detection or sw debounce being disabled */ 832 if ((line->irq && !READ_ONCE(line->sw_debounced)) || 833 (!debounce_period_us && READ_ONCE(line->sw_debounced))) 834 edge_detector_stop(line); 835 836 return edge_detector_setup(line, lc, line_idx, eflags); 837 } 838 839 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc, 840 unsigned int line_idx) 841 { 842 unsigned int i; 843 u64 mask = BIT_ULL(line_idx); 844 845 for (i = 0; i < lc->num_attrs; i++) { 846 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) && 847 (lc->attrs[i].mask & mask)) 848 return lc->attrs[i].attr.flags; 849 } 850 return lc->flags; 851 } 852 853 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc, 854 unsigned int line_idx) 855 { 856 unsigned int i; 857 u64 mask = BIT_ULL(line_idx); 858 859 for (i = 0; i < lc->num_attrs; i++) { 860 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) && 861 (lc->attrs[i].mask & mask)) 862 return !!(lc->attrs[i].attr.values & mask); 863 } 864 return 0; 865 } 866 867 static int gpio_v2_line_flags_validate(u64 flags) 868 { 869 /* Return an error if an unknown flag is set */ 870 if (flags & ~GPIO_V2_LINE_VALID_FLAGS) 871 return -EINVAL; 872 873 /* 874 * Do not allow both INPUT and OUTPUT flags to be set as they are 875 * contradictory. 876 */ 877 if ((flags & GPIO_V2_LINE_FLAG_INPUT) && 878 (flags & GPIO_V2_LINE_FLAG_OUTPUT)) 879 return -EINVAL; 880 881 /* Edge detection requires explicit input. */ 882 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) && 883 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 884 return -EINVAL; 885 886 /* 887 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single 888 * request. If the hardware actually supports enabling both at the 889 * same time the electrical result would be disastrous. 890 */ 891 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) && 892 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE)) 893 return -EINVAL; 894 895 /* Drive requires explicit output direction. */ 896 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) && 897 !(flags & GPIO_V2_LINE_FLAG_OUTPUT)) 898 return -EINVAL; 899 900 /* Bias requires explicit direction. */ 901 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) && 902 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS)) 903 return -EINVAL; 904 905 /* Only one bias flag can be set. */ 906 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) && 907 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | 908 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) || 909 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) && 910 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) 911 return -EINVAL; 912 913 return 0; 914 } 915 916 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc, 917 unsigned int num_lines) 918 { 919 unsigned int i; 920 u64 flags; 921 int ret; 922 923 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX) 924 return -EINVAL; 925 926 if (memchr_inv(lc->padding, 0, sizeof(lc->padding))) 927 return -EINVAL; 928 929 for (i = 0; i < num_lines; i++) { 930 flags = gpio_v2_line_config_flags(lc, i); 931 ret = gpio_v2_line_flags_validate(flags); 932 if (ret) 933 return ret; 934 935 /* debounce requires explicit input */ 936 if (gpio_v2_line_config_debounced(lc, i) && 937 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 938 return -EINVAL; 939 } 940 return 0; 941 } 942 943 static void gpio_v2_line_config_flags_to_desc_flags(u64 flags, 944 unsigned long *flagsp) 945 { 946 assign_bit(FLAG_ACTIVE_LOW, flagsp, 947 flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW); 948 949 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) 950 set_bit(FLAG_IS_OUT, flagsp); 951 else if (flags & GPIO_V2_LINE_FLAG_INPUT) 952 clear_bit(FLAG_IS_OUT, flagsp); 953 954 assign_bit(FLAG_EDGE_RISING, flagsp, 955 flags & GPIO_V2_LINE_FLAG_EDGE_RISING); 956 assign_bit(FLAG_EDGE_FALLING, flagsp, 957 flags & GPIO_V2_LINE_FLAG_EDGE_FALLING); 958 959 assign_bit(FLAG_OPEN_DRAIN, flagsp, 960 flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN); 961 assign_bit(FLAG_OPEN_SOURCE, flagsp, 962 flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE); 963 964 assign_bit(FLAG_PULL_UP, flagsp, 965 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP); 966 assign_bit(FLAG_PULL_DOWN, flagsp, 967 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN); 968 assign_bit(FLAG_BIAS_DISABLE, flagsp, 969 flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED); 970 } 971 972 static long linereq_get_values(struct linereq *lr, void __user *ip) 973 { 974 struct gpio_v2_line_values lv; 975 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 976 struct gpio_desc **descs; 977 unsigned int i, didx, num_get; 978 bool val; 979 int ret; 980 981 /* NOTE: It's ok to read values of output lines. */ 982 if (copy_from_user(&lv, ip, sizeof(lv))) 983 return -EFAULT; 984 985 for (num_get = 0, i = 0; i < lr->num_lines; i++) { 986 if (lv.mask & BIT_ULL(i)) { 987 num_get++; 988 descs = &lr->lines[i].desc; 989 } 990 } 991 992 if (num_get == 0) 993 return -EINVAL; 994 995 if (num_get != 1) { 996 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL); 997 if (!descs) 998 return -ENOMEM; 999 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1000 if (lv.mask & BIT_ULL(i)) { 1001 descs[didx] = lr->lines[i].desc; 1002 didx++; 1003 } 1004 } 1005 } 1006 ret = gpiod_get_array_value_complex(false, true, num_get, 1007 descs, NULL, vals); 1008 1009 if (num_get != 1) 1010 kfree(descs); 1011 if (ret) 1012 return ret; 1013 1014 lv.bits = 0; 1015 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1016 if (lv.mask & BIT_ULL(i)) { 1017 if (lr->lines[i].sw_debounced) 1018 val = debounced_value(&lr->lines[i]); 1019 else 1020 val = test_bit(didx, vals); 1021 if (val) 1022 lv.bits |= BIT_ULL(i); 1023 didx++; 1024 } 1025 } 1026 1027 if (copy_to_user(ip, &lv, sizeof(lv))) 1028 return -EFAULT; 1029 1030 return 0; 1031 } 1032 1033 static long linereq_set_values_unlocked(struct linereq *lr, 1034 struct gpio_v2_line_values *lv) 1035 { 1036 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1037 struct gpio_desc **descs; 1038 unsigned int i, didx, num_set; 1039 int ret; 1040 1041 bitmap_zero(vals, GPIO_V2_LINES_MAX); 1042 for (num_set = 0, i = 0; i < lr->num_lines; i++) { 1043 if (lv->mask & BIT_ULL(i)) { 1044 if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags)) 1045 return -EPERM; 1046 if (lv->bits & BIT_ULL(i)) 1047 __set_bit(num_set, vals); 1048 num_set++; 1049 descs = &lr->lines[i].desc; 1050 } 1051 } 1052 if (num_set == 0) 1053 return -EINVAL; 1054 1055 if (num_set != 1) { 1056 /* build compacted desc array and values */ 1057 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL); 1058 if (!descs) 1059 return -ENOMEM; 1060 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1061 if (lv->mask & BIT_ULL(i)) { 1062 descs[didx] = lr->lines[i].desc; 1063 didx++; 1064 } 1065 } 1066 } 1067 ret = gpiod_set_array_value_complex(false, true, num_set, 1068 descs, NULL, vals); 1069 1070 if (num_set != 1) 1071 kfree(descs); 1072 return ret; 1073 } 1074 1075 static long linereq_set_values(struct linereq *lr, void __user *ip) 1076 { 1077 struct gpio_v2_line_values lv; 1078 int ret; 1079 1080 if (copy_from_user(&lv, ip, sizeof(lv))) 1081 return -EFAULT; 1082 1083 mutex_lock(&lr->config_mutex); 1084 1085 ret = linereq_set_values_unlocked(lr, &lv); 1086 1087 mutex_unlock(&lr->config_mutex); 1088 1089 return ret; 1090 } 1091 1092 static long linereq_set_config_unlocked(struct linereq *lr, 1093 struct gpio_v2_line_config *lc) 1094 { 1095 struct gpio_desc *desc; 1096 unsigned int i; 1097 u64 flags; 1098 bool polarity_change; 1099 int ret; 1100 1101 for (i = 0; i < lr->num_lines; i++) { 1102 desc = lr->lines[i].desc; 1103 flags = gpio_v2_line_config_flags(lc, i); 1104 polarity_change = 1105 (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) != 1106 ((flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) != 0)); 1107 1108 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1109 /* 1110 * Lines have to be requested explicitly for input 1111 * or output, else the line will be treated "as is". 1112 */ 1113 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1114 int val = gpio_v2_line_config_output_value(lc, i); 1115 1116 edge_detector_stop(&lr->lines[i]); 1117 ret = gpiod_direction_output(desc, val); 1118 if (ret) 1119 return ret; 1120 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1121 ret = gpiod_direction_input(desc); 1122 if (ret) 1123 return ret; 1124 1125 ret = edge_detector_update(&lr->lines[i], lc, i, 1126 flags & GPIO_V2_LINE_EDGE_FLAGS, 1127 polarity_change); 1128 if (ret) 1129 return ret; 1130 } 1131 1132 blocking_notifier_call_chain(&desc->gdev->notifier, 1133 GPIO_V2_LINE_CHANGED_CONFIG, 1134 desc); 1135 } 1136 return 0; 1137 } 1138 1139 static long linereq_set_config(struct linereq *lr, void __user *ip) 1140 { 1141 struct gpio_v2_line_config lc; 1142 int ret; 1143 1144 if (copy_from_user(&lc, ip, sizeof(lc))) 1145 return -EFAULT; 1146 1147 ret = gpio_v2_line_config_validate(&lc, lr->num_lines); 1148 if (ret) 1149 return ret; 1150 1151 mutex_lock(&lr->config_mutex); 1152 1153 ret = linereq_set_config_unlocked(lr, &lc); 1154 1155 mutex_unlock(&lr->config_mutex); 1156 1157 return ret; 1158 } 1159 1160 static long linereq_ioctl(struct file *file, unsigned int cmd, 1161 unsigned long arg) 1162 { 1163 struct linereq *lr = file->private_data; 1164 void __user *ip = (void __user *)arg; 1165 1166 if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL) 1167 return linereq_get_values(lr, ip); 1168 else if (cmd == GPIO_V2_LINE_SET_VALUES_IOCTL) 1169 return linereq_set_values(lr, ip); 1170 else if (cmd == GPIO_V2_LINE_SET_CONFIG_IOCTL) 1171 return linereq_set_config(lr, ip); 1172 1173 return -EINVAL; 1174 } 1175 1176 #ifdef CONFIG_COMPAT 1177 static long linereq_ioctl_compat(struct file *file, unsigned int cmd, 1178 unsigned long arg) 1179 { 1180 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1181 } 1182 #endif 1183 1184 static __poll_t linereq_poll(struct file *file, 1185 struct poll_table_struct *wait) 1186 { 1187 struct linereq *lr = file->private_data; 1188 __poll_t events = 0; 1189 1190 poll_wait(file, &lr->wait, wait); 1191 1192 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events, 1193 &lr->wait.lock)) 1194 events = EPOLLIN | EPOLLRDNORM; 1195 1196 return events; 1197 } 1198 1199 static ssize_t linereq_read(struct file *file, 1200 char __user *buf, 1201 size_t count, 1202 loff_t *f_ps) 1203 { 1204 struct linereq *lr = file->private_data; 1205 struct gpio_v2_line_event le; 1206 ssize_t bytes_read = 0; 1207 int ret; 1208 1209 if (count < sizeof(le)) 1210 return -EINVAL; 1211 1212 do { 1213 spin_lock(&lr->wait.lock); 1214 if (kfifo_is_empty(&lr->events)) { 1215 if (bytes_read) { 1216 spin_unlock(&lr->wait.lock); 1217 return bytes_read; 1218 } 1219 1220 if (file->f_flags & O_NONBLOCK) { 1221 spin_unlock(&lr->wait.lock); 1222 return -EAGAIN; 1223 } 1224 1225 ret = wait_event_interruptible_locked(lr->wait, 1226 !kfifo_is_empty(&lr->events)); 1227 if (ret) { 1228 spin_unlock(&lr->wait.lock); 1229 return ret; 1230 } 1231 } 1232 1233 ret = kfifo_out(&lr->events, &le, 1); 1234 spin_unlock(&lr->wait.lock); 1235 if (ret != 1) { 1236 /* 1237 * This should never happen - we were holding the 1238 * lock from the moment we learned the fifo is no 1239 * longer empty until now. 1240 */ 1241 ret = -EIO; 1242 break; 1243 } 1244 1245 if (copy_to_user(buf + bytes_read, &le, sizeof(le))) 1246 return -EFAULT; 1247 bytes_read += sizeof(le); 1248 } while (count >= bytes_read + sizeof(le)); 1249 1250 return bytes_read; 1251 } 1252 1253 static void linereq_free(struct linereq *lr) 1254 { 1255 unsigned int i; 1256 1257 for (i = 0; i < lr->num_lines; i++) { 1258 edge_detector_stop(&lr->lines[i]); 1259 if (lr->lines[i].desc) 1260 gpiod_free(lr->lines[i].desc); 1261 } 1262 kfifo_free(&lr->events); 1263 kfree(lr->label); 1264 put_device(&lr->gdev->dev); 1265 kfree(lr); 1266 } 1267 1268 static int linereq_release(struct inode *inode, struct file *file) 1269 { 1270 struct linereq *lr = file->private_data; 1271 1272 linereq_free(lr); 1273 return 0; 1274 } 1275 1276 static const struct file_operations line_fileops = { 1277 .release = linereq_release, 1278 .read = linereq_read, 1279 .poll = linereq_poll, 1280 .owner = THIS_MODULE, 1281 .llseek = noop_llseek, 1282 .unlocked_ioctl = linereq_ioctl, 1283 #ifdef CONFIG_COMPAT 1284 .compat_ioctl = linereq_ioctl_compat, 1285 #endif 1286 }; 1287 1288 static int linereq_create(struct gpio_device *gdev, void __user *ip) 1289 { 1290 struct gpio_v2_line_request ulr; 1291 struct gpio_v2_line_config *lc; 1292 struct linereq *lr; 1293 struct file *file; 1294 u64 flags; 1295 unsigned int i; 1296 int fd, ret; 1297 1298 if (copy_from_user(&ulr, ip, sizeof(ulr))) 1299 return -EFAULT; 1300 1301 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX)) 1302 return -EINVAL; 1303 1304 if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding))) 1305 return -EINVAL; 1306 1307 lc = &ulr.config; 1308 ret = gpio_v2_line_config_validate(lc, ulr.num_lines); 1309 if (ret) 1310 return ret; 1311 1312 lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL); 1313 if (!lr) 1314 return -ENOMEM; 1315 1316 lr->gdev = gdev; 1317 get_device(&gdev->dev); 1318 1319 for (i = 0; i < ulr.num_lines; i++) { 1320 lr->lines[i].req = lr; 1321 WRITE_ONCE(lr->lines[i].sw_debounced, 0); 1322 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func); 1323 } 1324 1325 if (ulr.consumer[0] != '\0') { 1326 /* label is only initialized if consumer is set */ 1327 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1, 1328 GFP_KERNEL); 1329 if (!lr->label) { 1330 ret = -ENOMEM; 1331 goto out_free_linereq; 1332 } 1333 } 1334 1335 mutex_init(&lr->config_mutex); 1336 init_waitqueue_head(&lr->wait); 1337 lr->event_buffer_size = ulr.event_buffer_size; 1338 if (lr->event_buffer_size == 0) 1339 lr->event_buffer_size = ulr.num_lines * 16; 1340 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16) 1341 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16; 1342 1343 atomic_set(&lr->seqno, 0); 1344 lr->num_lines = ulr.num_lines; 1345 1346 /* Request each GPIO */ 1347 for (i = 0; i < ulr.num_lines; i++) { 1348 u32 offset = ulr.offsets[i]; 1349 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset); 1350 1351 if (IS_ERR(desc)) { 1352 ret = PTR_ERR(desc); 1353 goto out_free_linereq; 1354 } 1355 1356 ret = gpiod_request(desc, lr->label); 1357 if (ret) 1358 goto out_free_linereq; 1359 1360 lr->lines[i].desc = desc; 1361 flags = gpio_v2_line_config_flags(lc, i); 1362 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1363 1364 ret = gpiod_set_transitory(desc, false); 1365 if (ret < 0) 1366 goto out_free_linereq; 1367 1368 /* 1369 * Lines have to be requested explicitly for input 1370 * or output, else the line will be treated "as is". 1371 */ 1372 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1373 int val = gpio_v2_line_config_output_value(lc, i); 1374 1375 ret = gpiod_direction_output(desc, val); 1376 if (ret) 1377 goto out_free_linereq; 1378 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1379 ret = gpiod_direction_input(desc); 1380 if (ret) 1381 goto out_free_linereq; 1382 1383 ret = edge_detector_setup(&lr->lines[i], lc, i, 1384 flags & GPIO_V2_LINE_EDGE_FLAGS); 1385 if (ret) 1386 goto out_free_linereq; 1387 } 1388 1389 blocking_notifier_call_chain(&desc->gdev->notifier, 1390 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 1391 1392 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 1393 offset); 1394 } 1395 1396 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 1397 if (fd < 0) { 1398 ret = fd; 1399 goto out_free_linereq; 1400 } 1401 1402 file = anon_inode_getfile("gpio-line", &line_fileops, lr, 1403 O_RDONLY | O_CLOEXEC); 1404 if (IS_ERR(file)) { 1405 ret = PTR_ERR(file); 1406 goto out_put_unused_fd; 1407 } 1408 1409 ulr.fd = fd; 1410 if (copy_to_user(ip, &ulr, sizeof(ulr))) { 1411 /* 1412 * fput() will trigger the release() callback, so do not go onto 1413 * the regular error cleanup path here. 1414 */ 1415 fput(file); 1416 put_unused_fd(fd); 1417 return -EFAULT; 1418 } 1419 1420 fd_install(fd, file); 1421 1422 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 1423 lr->num_lines); 1424 1425 return 0; 1426 1427 out_put_unused_fd: 1428 put_unused_fd(fd); 1429 out_free_linereq: 1430 linereq_free(lr); 1431 return ret; 1432 } 1433 1434 #ifdef CONFIG_GPIO_CDEV_V1 1435 1436 /* 1437 * GPIO line event management 1438 */ 1439 1440 /** 1441 * struct lineevent_state - contains the state of a userspace event 1442 * @gdev: the GPIO device the event pertains to 1443 * @label: consumer label used to tag descriptors 1444 * @desc: the GPIO descriptor held by this event 1445 * @eflags: the event flags this line was requested with 1446 * @irq: the interrupt that trigger in response to events on this GPIO 1447 * @wait: wait queue that handles blocking reads of events 1448 * @events: KFIFO for the GPIO events 1449 * @timestamp: cache for the timestamp storing it between hardirq 1450 * and IRQ thread, used to bring the timestamp close to the actual 1451 * event 1452 */ 1453 struct lineevent_state { 1454 struct gpio_device *gdev; 1455 const char *label; 1456 struct gpio_desc *desc; 1457 u32 eflags; 1458 int irq; 1459 wait_queue_head_t wait; 1460 DECLARE_KFIFO(events, struct gpioevent_data, 16); 1461 u64 timestamp; 1462 }; 1463 1464 #define GPIOEVENT_REQUEST_VALID_FLAGS \ 1465 (GPIOEVENT_REQUEST_RISING_EDGE | \ 1466 GPIOEVENT_REQUEST_FALLING_EDGE) 1467 1468 static __poll_t lineevent_poll(struct file *file, 1469 struct poll_table_struct *wait) 1470 { 1471 struct lineevent_state *le = file->private_data; 1472 __poll_t events = 0; 1473 1474 poll_wait(file, &le->wait, wait); 1475 1476 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock)) 1477 events = EPOLLIN | EPOLLRDNORM; 1478 1479 return events; 1480 } 1481 1482 static ssize_t lineevent_get_size(void) 1483 { 1484 #if defined(CONFIG_X86_64) && !defined(CONFIG_UML) 1485 /* i386 has no padding after 'id' */ 1486 if (in_ia32_syscall()) { 1487 struct compat_gpioeevent_data { 1488 compat_u64 timestamp; 1489 u32 id; 1490 }; 1491 1492 return sizeof(struct compat_gpioeevent_data); 1493 } 1494 #endif 1495 return sizeof(struct gpioevent_data); 1496 } 1497 1498 static ssize_t lineevent_read(struct file *file, 1499 char __user *buf, 1500 size_t count, 1501 loff_t *f_ps) 1502 { 1503 struct lineevent_state *le = file->private_data; 1504 struct gpioevent_data ge; 1505 ssize_t bytes_read = 0; 1506 ssize_t ge_size; 1507 int ret; 1508 1509 /* 1510 * When compatible system call is being used the struct gpioevent_data, 1511 * in case of at least ia32, has different size due to the alignment 1512 * differences. Because we have first member 64 bits followed by one of 1513 * 32 bits there is no gap between them. The only difference is the 1514 * padding at the end of the data structure. Hence, we calculate the 1515 * actual sizeof() and pass this as an argument to copy_to_user() to 1516 * drop unneeded bytes from the output. 1517 */ 1518 ge_size = lineevent_get_size(); 1519 if (count < ge_size) 1520 return -EINVAL; 1521 1522 do { 1523 spin_lock(&le->wait.lock); 1524 if (kfifo_is_empty(&le->events)) { 1525 if (bytes_read) { 1526 spin_unlock(&le->wait.lock); 1527 return bytes_read; 1528 } 1529 1530 if (file->f_flags & O_NONBLOCK) { 1531 spin_unlock(&le->wait.lock); 1532 return -EAGAIN; 1533 } 1534 1535 ret = wait_event_interruptible_locked(le->wait, 1536 !kfifo_is_empty(&le->events)); 1537 if (ret) { 1538 spin_unlock(&le->wait.lock); 1539 return ret; 1540 } 1541 } 1542 1543 ret = kfifo_out(&le->events, &ge, 1); 1544 spin_unlock(&le->wait.lock); 1545 if (ret != 1) { 1546 /* 1547 * This should never happen - we were holding the lock 1548 * from the moment we learned the fifo is no longer 1549 * empty until now. 1550 */ 1551 ret = -EIO; 1552 break; 1553 } 1554 1555 if (copy_to_user(buf + bytes_read, &ge, ge_size)) 1556 return -EFAULT; 1557 bytes_read += ge_size; 1558 } while (count >= bytes_read + ge_size); 1559 1560 return bytes_read; 1561 } 1562 1563 static void lineevent_free(struct lineevent_state *le) 1564 { 1565 if (le->irq) 1566 free_irq(le->irq, le); 1567 if (le->desc) 1568 gpiod_free(le->desc); 1569 kfree(le->label); 1570 put_device(&le->gdev->dev); 1571 kfree(le); 1572 } 1573 1574 static int lineevent_release(struct inode *inode, struct file *file) 1575 { 1576 lineevent_free(file->private_data); 1577 return 0; 1578 } 1579 1580 static long lineevent_ioctl(struct file *file, unsigned int cmd, 1581 unsigned long arg) 1582 { 1583 struct lineevent_state *le = file->private_data; 1584 void __user *ip = (void __user *)arg; 1585 struct gpiohandle_data ghd; 1586 1587 /* 1588 * We can get the value for an event line but not set it, 1589 * because it is input by definition. 1590 */ 1591 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { 1592 int val; 1593 1594 memset(&ghd, 0, sizeof(ghd)); 1595 1596 val = gpiod_get_value_cansleep(le->desc); 1597 if (val < 0) 1598 return val; 1599 ghd.values[0] = val; 1600 1601 if (copy_to_user(ip, &ghd, sizeof(ghd))) 1602 return -EFAULT; 1603 1604 return 0; 1605 } 1606 return -EINVAL; 1607 } 1608 1609 #ifdef CONFIG_COMPAT 1610 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd, 1611 unsigned long arg) 1612 { 1613 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1614 } 1615 #endif 1616 1617 static const struct file_operations lineevent_fileops = { 1618 .release = lineevent_release, 1619 .read = lineevent_read, 1620 .poll = lineevent_poll, 1621 .owner = THIS_MODULE, 1622 .llseek = noop_llseek, 1623 .unlocked_ioctl = lineevent_ioctl, 1624 #ifdef CONFIG_COMPAT 1625 .compat_ioctl = lineevent_ioctl_compat, 1626 #endif 1627 }; 1628 1629 static irqreturn_t lineevent_irq_thread(int irq, void *p) 1630 { 1631 struct lineevent_state *le = p; 1632 struct gpioevent_data ge; 1633 int ret; 1634 1635 /* Do not leak kernel stack to userspace */ 1636 memset(&ge, 0, sizeof(ge)); 1637 1638 /* 1639 * We may be running from a nested threaded interrupt in which case 1640 * we didn't get the timestamp from lineevent_irq_handler(). 1641 */ 1642 if (!le->timestamp) 1643 ge.timestamp = ktime_get_ns(); 1644 else 1645 ge.timestamp = le->timestamp; 1646 1647 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE 1648 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 1649 int level = gpiod_get_value_cansleep(le->desc); 1650 1651 if (level) 1652 /* Emit low-to-high event */ 1653 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 1654 else 1655 /* Emit high-to-low event */ 1656 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 1657 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) { 1658 /* Emit low-to-high event */ 1659 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 1660 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 1661 /* Emit high-to-low event */ 1662 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 1663 } else { 1664 return IRQ_NONE; 1665 } 1666 1667 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge, 1668 1, &le->wait.lock); 1669 if (ret) 1670 wake_up_poll(&le->wait, EPOLLIN); 1671 else 1672 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 1673 1674 return IRQ_HANDLED; 1675 } 1676 1677 static irqreturn_t lineevent_irq_handler(int irq, void *p) 1678 { 1679 struct lineevent_state *le = p; 1680 1681 /* 1682 * Just store the timestamp in hardirq context so we get it as 1683 * close in time as possible to the actual event. 1684 */ 1685 le->timestamp = ktime_get_ns(); 1686 1687 return IRQ_WAKE_THREAD; 1688 } 1689 1690 static int lineevent_create(struct gpio_device *gdev, void __user *ip) 1691 { 1692 struct gpioevent_request eventreq; 1693 struct lineevent_state *le; 1694 struct gpio_desc *desc; 1695 struct file *file; 1696 u32 offset; 1697 u32 lflags; 1698 u32 eflags; 1699 int fd; 1700 int ret; 1701 int irq, irqflags = 0; 1702 1703 if (copy_from_user(&eventreq, ip, sizeof(eventreq))) 1704 return -EFAULT; 1705 1706 offset = eventreq.lineoffset; 1707 lflags = eventreq.handleflags; 1708 eflags = eventreq.eventflags; 1709 1710 desc = gpiochip_get_desc(gdev->chip, offset); 1711 if (IS_ERR(desc)) 1712 return PTR_ERR(desc); 1713 1714 /* Return an error if a unknown flag is set */ 1715 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) || 1716 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS)) 1717 return -EINVAL; 1718 1719 /* This is just wrong: we don't look for events on output lines */ 1720 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) || 1721 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 1722 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 1723 return -EINVAL; 1724 1725 /* Only one bias flag can be set. */ 1726 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 1727 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 1728 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 1729 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 1730 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 1731 return -EINVAL; 1732 1733 le = kzalloc(sizeof(*le), GFP_KERNEL); 1734 if (!le) 1735 return -ENOMEM; 1736 le->gdev = gdev; 1737 get_device(&gdev->dev); 1738 1739 if (eventreq.consumer_label[0] != '\0') { 1740 /* label is only initialized if consumer_label is set */ 1741 le->label = kstrndup(eventreq.consumer_label, 1742 sizeof(eventreq.consumer_label) - 1, 1743 GFP_KERNEL); 1744 if (!le->label) { 1745 ret = -ENOMEM; 1746 goto out_free_le; 1747 } 1748 } 1749 1750 ret = gpiod_request(desc, le->label); 1751 if (ret) 1752 goto out_free_le; 1753 le->desc = desc; 1754 le->eflags = eflags; 1755 1756 linehandle_flags_to_desc_flags(lflags, &desc->flags); 1757 1758 ret = gpiod_direction_input(desc); 1759 if (ret) 1760 goto out_free_le; 1761 1762 blocking_notifier_call_chain(&desc->gdev->notifier, 1763 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 1764 1765 irq = gpiod_to_irq(desc); 1766 if (irq <= 0) { 1767 ret = -ENODEV; 1768 goto out_free_le; 1769 } 1770 le->irq = irq; 1771 1772 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE) 1773 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 1774 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 1775 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE) 1776 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 1777 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 1778 irqflags |= IRQF_ONESHOT; 1779 1780 INIT_KFIFO(le->events); 1781 init_waitqueue_head(&le->wait); 1782 1783 /* Request a thread to read the events */ 1784 ret = request_threaded_irq(le->irq, 1785 lineevent_irq_handler, 1786 lineevent_irq_thread, 1787 irqflags, 1788 le->label, 1789 le); 1790 if (ret) 1791 goto out_free_le; 1792 1793 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 1794 if (fd < 0) { 1795 ret = fd; 1796 goto out_free_le; 1797 } 1798 1799 file = anon_inode_getfile("gpio-event", 1800 &lineevent_fileops, 1801 le, 1802 O_RDONLY | O_CLOEXEC); 1803 if (IS_ERR(file)) { 1804 ret = PTR_ERR(file); 1805 goto out_put_unused_fd; 1806 } 1807 1808 eventreq.fd = fd; 1809 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) { 1810 /* 1811 * fput() will trigger the release() callback, so do not go onto 1812 * the regular error cleanup path here. 1813 */ 1814 fput(file); 1815 put_unused_fd(fd); 1816 return -EFAULT; 1817 } 1818 1819 fd_install(fd, file); 1820 1821 return 0; 1822 1823 out_put_unused_fd: 1824 put_unused_fd(fd); 1825 out_free_le: 1826 lineevent_free(le); 1827 return ret; 1828 } 1829 1830 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2, 1831 struct gpioline_info *info_v1) 1832 { 1833 u64 flagsv2 = info_v2->flags; 1834 1835 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name)); 1836 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer)); 1837 info_v1->line_offset = info_v2->offset; 1838 info_v1->flags = 0; 1839 1840 if (flagsv2 & GPIO_V2_LINE_FLAG_USED) 1841 info_v1->flags |= GPIOLINE_FLAG_KERNEL; 1842 1843 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT) 1844 info_v1->flags |= GPIOLINE_FLAG_IS_OUT; 1845 1846 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 1847 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW; 1848 1849 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN) 1850 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN; 1851 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE) 1852 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE; 1853 1854 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP) 1855 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP; 1856 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) 1857 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN; 1858 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED) 1859 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE; 1860 } 1861 1862 static void gpio_v2_line_info_changed_to_v1( 1863 struct gpio_v2_line_info_changed *lic_v2, 1864 struct gpioline_info_changed *lic_v1) 1865 { 1866 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info); 1867 lic_v1->timestamp = lic_v2->timestamp_ns; 1868 lic_v1->event_type = lic_v2->event_type; 1869 } 1870 1871 #endif /* CONFIG_GPIO_CDEV_V1 */ 1872 1873 static void gpio_desc_to_lineinfo(struct gpio_desc *desc, 1874 struct gpio_v2_line_info *info) 1875 { 1876 struct gpio_chip *gc = desc->gdev->chip; 1877 bool ok_for_pinctrl; 1878 unsigned long flags; 1879 u32 debounce_period_us; 1880 unsigned int num_attrs = 0; 1881 1882 memset(info, 0, sizeof(*info)); 1883 info->offset = gpio_chip_hwgpio(desc); 1884 1885 /* 1886 * This function takes a mutex so we must check this before taking 1887 * the spinlock. 1888 * 1889 * FIXME: find a non-racy way to retrieve this information. Maybe a 1890 * lock common to both frameworks? 1891 */ 1892 ok_for_pinctrl = 1893 pinctrl_gpio_can_use_line(gc->base + info->offset); 1894 1895 spin_lock_irqsave(&gpio_lock, flags); 1896 1897 if (desc->name) 1898 strscpy(info->name, desc->name, sizeof(info->name)); 1899 1900 if (desc->label) 1901 strscpy(info->consumer, desc->label, sizeof(info->consumer)); 1902 1903 /* 1904 * Userspace only need to know that the kernel is using this GPIO so 1905 * it can't use it. 1906 */ 1907 info->flags = 0; 1908 if (test_bit(FLAG_REQUESTED, &desc->flags) || 1909 test_bit(FLAG_IS_HOGGED, &desc->flags) || 1910 test_bit(FLAG_USED_AS_IRQ, &desc->flags) || 1911 test_bit(FLAG_EXPORT, &desc->flags) || 1912 test_bit(FLAG_SYSFS, &desc->flags) || 1913 !ok_for_pinctrl) 1914 info->flags |= GPIO_V2_LINE_FLAG_USED; 1915 1916 if (test_bit(FLAG_IS_OUT, &desc->flags)) 1917 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT; 1918 else 1919 info->flags |= GPIO_V2_LINE_FLAG_INPUT; 1920 1921 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) 1922 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW; 1923 1924 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) 1925 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN; 1926 if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) 1927 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE; 1928 1929 if (test_bit(FLAG_BIAS_DISABLE, &desc->flags)) 1930 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED; 1931 if (test_bit(FLAG_PULL_DOWN, &desc->flags)) 1932 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN; 1933 if (test_bit(FLAG_PULL_UP, &desc->flags)) 1934 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP; 1935 1936 if (test_bit(FLAG_EDGE_RISING, &desc->flags)) 1937 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING; 1938 if (test_bit(FLAG_EDGE_FALLING, &desc->flags)) 1939 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING; 1940 1941 debounce_period_us = READ_ONCE(desc->debounce_period_us); 1942 if (debounce_period_us) { 1943 info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; 1944 info->attrs[num_attrs].debounce_period_us = debounce_period_us; 1945 num_attrs++; 1946 } 1947 info->num_attrs = num_attrs; 1948 1949 spin_unlock_irqrestore(&gpio_lock, flags); 1950 } 1951 1952 struct gpio_chardev_data { 1953 struct gpio_device *gdev; 1954 wait_queue_head_t wait; 1955 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32); 1956 struct notifier_block lineinfo_changed_nb; 1957 unsigned long *watched_lines; 1958 #ifdef CONFIG_GPIO_CDEV_V1 1959 atomic_t watch_abi_version; 1960 #endif 1961 }; 1962 1963 #ifdef CONFIG_GPIO_CDEV_V1 1964 /* 1965 * returns 0 if the versions match, else the previously selected ABI version 1966 */ 1967 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata, 1968 unsigned int version) 1969 { 1970 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version); 1971 1972 if (abiv == version) 1973 return 0; 1974 1975 return abiv; 1976 } 1977 #endif 1978 1979 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, 1980 bool watch) 1981 { 1982 struct gpio_desc *desc; 1983 struct gpio_v2_line_info lineinfo; 1984 1985 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 1986 return -EFAULT; 1987 1988 if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding))) 1989 return -EINVAL; 1990 1991 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset); 1992 if (IS_ERR(desc)) 1993 return PTR_ERR(desc); 1994 1995 if (watch) { 1996 #ifdef CONFIG_GPIO_CDEV_V1 1997 if (lineinfo_ensure_abi_version(cdev, 2)) 1998 return -EPERM; 1999 #endif 2000 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines)) 2001 return -EBUSY; 2002 } 2003 gpio_desc_to_lineinfo(desc, &lineinfo); 2004 2005 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2006 if (watch) 2007 clear_bit(lineinfo.offset, cdev->watched_lines); 2008 return -EFAULT; 2009 } 2010 2011 return 0; 2012 } 2013 2014 /* 2015 * gpio_ioctl() - ioctl handler for the GPIO chardev 2016 */ 2017 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 2018 { 2019 struct gpio_chardev_data *cdev = file->private_data; 2020 struct gpio_device *gdev = cdev->gdev; 2021 struct gpio_chip *gc = gdev->chip; 2022 void __user *ip = (void __user *)arg; 2023 __u32 offset; 2024 2025 /* We fail any subsequent ioctl():s when the chip is gone */ 2026 if (!gc) 2027 return -ENODEV; 2028 2029 /* Fill in the struct and pass to userspace */ 2030 if (cmd == GPIO_GET_CHIPINFO_IOCTL) { 2031 struct gpiochip_info chipinfo; 2032 2033 memset(&chipinfo, 0, sizeof(chipinfo)); 2034 2035 strscpy(chipinfo.name, dev_name(&gdev->dev), 2036 sizeof(chipinfo.name)); 2037 strscpy(chipinfo.label, gdev->label, 2038 sizeof(chipinfo.label)); 2039 chipinfo.lines = gdev->ngpio; 2040 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo))) 2041 return -EFAULT; 2042 return 0; 2043 #ifdef CONFIG_GPIO_CDEV_V1 2044 } else if (cmd == GPIO_GET_LINEINFO_IOCTL) { 2045 struct gpio_desc *desc; 2046 struct gpioline_info lineinfo; 2047 struct gpio_v2_line_info lineinfo_v2; 2048 2049 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2050 return -EFAULT; 2051 2052 /* this doubles as a range check on line_offset */ 2053 desc = gpiochip_get_desc(gc, lineinfo.line_offset); 2054 if (IS_ERR(desc)) 2055 return PTR_ERR(desc); 2056 2057 gpio_desc_to_lineinfo(desc, &lineinfo_v2); 2058 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); 2059 2060 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) 2061 return -EFAULT; 2062 return 0; 2063 } else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) { 2064 return linehandle_create(gdev, ip); 2065 } else if (cmd == GPIO_GET_LINEEVENT_IOCTL) { 2066 return lineevent_create(gdev, ip); 2067 } else if (cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) { 2068 struct gpio_desc *desc; 2069 struct gpioline_info lineinfo; 2070 struct gpio_v2_line_info lineinfo_v2; 2071 2072 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2073 return -EFAULT; 2074 2075 /* this doubles as a range check on line_offset */ 2076 desc = gpiochip_get_desc(gc, lineinfo.line_offset); 2077 if (IS_ERR(desc)) 2078 return PTR_ERR(desc); 2079 2080 if (lineinfo_ensure_abi_version(cdev, 1)) 2081 return -EPERM; 2082 2083 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines)) 2084 return -EBUSY; 2085 2086 gpio_desc_to_lineinfo(desc, &lineinfo_v2); 2087 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); 2088 2089 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2090 clear_bit(lineinfo.line_offset, cdev->watched_lines); 2091 return -EFAULT; 2092 } 2093 2094 return 0; 2095 #endif /* CONFIG_GPIO_CDEV_V1 */ 2096 } else if (cmd == GPIO_V2_GET_LINEINFO_IOCTL || 2097 cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL) { 2098 return lineinfo_get(cdev, ip, 2099 cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL); 2100 } else if (cmd == GPIO_V2_GET_LINE_IOCTL) { 2101 return linereq_create(gdev, ip); 2102 } else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) { 2103 if (copy_from_user(&offset, ip, sizeof(offset))) 2104 return -EFAULT; 2105 2106 if (offset >= cdev->gdev->ngpio) 2107 return -EINVAL; 2108 2109 if (!test_and_clear_bit(offset, cdev->watched_lines)) 2110 return -EBUSY; 2111 2112 return 0; 2113 } 2114 return -EINVAL; 2115 } 2116 2117 #ifdef CONFIG_COMPAT 2118 static long gpio_ioctl_compat(struct file *file, unsigned int cmd, 2119 unsigned long arg) 2120 { 2121 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 2122 } 2123 #endif 2124 2125 static struct gpio_chardev_data * 2126 to_gpio_chardev_data(struct notifier_block *nb) 2127 { 2128 return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb); 2129 } 2130 2131 static int lineinfo_changed_notify(struct notifier_block *nb, 2132 unsigned long action, void *data) 2133 { 2134 struct gpio_chardev_data *cdev = to_gpio_chardev_data(nb); 2135 struct gpio_v2_line_info_changed chg; 2136 struct gpio_desc *desc = data; 2137 int ret; 2138 2139 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines)) 2140 return NOTIFY_DONE; 2141 2142 memset(&chg, 0, sizeof(chg)); 2143 chg.event_type = action; 2144 chg.timestamp_ns = ktime_get_ns(); 2145 gpio_desc_to_lineinfo(desc, &chg.info); 2146 2147 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock); 2148 if (ret) 2149 wake_up_poll(&cdev->wait, EPOLLIN); 2150 else 2151 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n"); 2152 2153 return NOTIFY_OK; 2154 } 2155 2156 static __poll_t lineinfo_watch_poll(struct file *file, 2157 struct poll_table_struct *pollt) 2158 { 2159 struct gpio_chardev_data *cdev = file->private_data; 2160 __poll_t events = 0; 2161 2162 poll_wait(file, &cdev->wait, pollt); 2163 2164 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events, 2165 &cdev->wait.lock)) 2166 events = EPOLLIN | EPOLLRDNORM; 2167 2168 return events; 2169 } 2170 2171 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, 2172 size_t count, loff_t *off) 2173 { 2174 struct gpio_chardev_data *cdev = file->private_data; 2175 struct gpio_v2_line_info_changed event; 2176 ssize_t bytes_read = 0; 2177 int ret; 2178 size_t event_size; 2179 2180 #ifndef CONFIG_GPIO_CDEV_V1 2181 event_size = sizeof(struct gpio_v2_line_info_changed); 2182 if (count < event_size) 2183 return -EINVAL; 2184 #endif 2185 2186 do { 2187 spin_lock(&cdev->wait.lock); 2188 if (kfifo_is_empty(&cdev->events)) { 2189 if (bytes_read) { 2190 spin_unlock(&cdev->wait.lock); 2191 return bytes_read; 2192 } 2193 2194 if (file->f_flags & O_NONBLOCK) { 2195 spin_unlock(&cdev->wait.lock); 2196 return -EAGAIN; 2197 } 2198 2199 ret = wait_event_interruptible_locked(cdev->wait, 2200 !kfifo_is_empty(&cdev->events)); 2201 if (ret) { 2202 spin_unlock(&cdev->wait.lock); 2203 return ret; 2204 } 2205 } 2206 #ifdef CONFIG_GPIO_CDEV_V1 2207 /* must be after kfifo check so watch_abi_version is set */ 2208 if (atomic_read(&cdev->watch_abi_version) == 2) 2209 event_size = sizeof(struct gpio_v2_line_info_changed); 2210 else 2211 event_size = sizeof(struct gpioline_info_changed); 2212 if (count < event_size) { 2213 spin_unlock(&cdev->wait.lock); 2214 return -EINVAL; 2215 } 2216 #endif 2217 ret = kfifo_out(&cdev->events, &event, 1); 2218 spin_unlock(&cdev->wait.lock); 2219 if (ret != 1) { 2220 ret = -EIO; 2221 break; 2222 /* We should never get here. See lineevent_read(). */ 2223 } 2224 2225 #ifdef CONFIG_GPIO_CDEV_V1 2226 if (event_size == sizeof(struct gpio_v2_line_info_changed)) { 2227 if (copy_to_user(buf + bytes_read, &event, event_size)) 2228 return -EFAULT; 2229 } else { 2230 struct gpioline_info_changed event_v1; 2231 2232 gpio_v2_line_info_changed_to_v1(&event, &event_v1); 2233 if (copy_to_user(buf + bytes_read, &event_v1, 2234 event_size)) 2235 return -EFAULT; 2236 } 2237 #else 2238 if (copy_to_user(buf + bytes_read, &event, event_size)) 2239 return -EFAULT; 2240 #endif 2241 bytes_read += event_size; 2242 } while (count >= bytes_read + sizeof(event)); 2243 2244 return bytes_read; 2245 } 2246 2247 /** 2248 * gpio_chrdev_open() - open the chardev for ioctl operations 2249 * @inode: inode for this chardev 2250 * @file: file struct for storing private data 2251 * Returns 0 on success 2252 */ 2253 static int gpio_chrdev_open(struct inode *inode, struct file *file) 2254 { 2255 struct gpio_device *gdev = container_of(inode->i_cdev, 2256 struct gpio_device, chrdev); 2257 struct gpio_chardev_data *cdev; 2258 int ret = -ENOMEM; 2259 2260 /* Fail on open if the backing gpiochip is gone */ 2261 if (!gdev->chip) 2262 return -ENODEV; 2263 2264 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL); 2265 if (!cdev) 2266 return -ENOMEM; 2267 2268 cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL); 2269 if (!cdev->watched_lines) 2270 goto out_free_cdev; 2271 2272 init_waitqueue_head(&cdev->wait); 2273 INIT_KFIFO(cdev->events); 2274 cdev->gdev = gdev; 2275 2276 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify; 2277 ret = blocking_notifier_chain_register(&gdev->notifier, 2278 &cdev->lineinfo_changed_nb); 2279 if (ret) 2280 goto out_free_bitmap; 2281 2282 get_device(&gdev->dev); 2283 file->private_data = cdev; 2284 2285 ret = nonseekable_open(inode, file); 2286 if (ret) 2287 goto out_unregister_notifier; 2288 2289 return ret; 2290 2291 out_unregister_notifier: 2292 blocking_notifier_chain_unregister(&gdev->notifier, 2293 &cdev->lineinfo_changed_nb); 2294 out_free_bitmap: 2295 bitmap_free(cdev->watched_lines); 2296 out_free_cdev: 2297 kfree(cdev); 2298 return ret; 2299 } 2300 2301 /** 2302 * gpio_chrdev_release() - close chardev after ioctl operations 2303 * @inode: inode for this chardev 2304 * @file: file struct for storing private data 2305 * Returns 0 on success 2306 */ 2307 static int gpio_chrdev_release(struct inode *inode, struct file *file) 2308 { 2309 struct gpio_chardev_data *cdev = file->private_data; 2310 struct gpio_device *gdev = cdev->gdev; 2311 2312 bitmap_free(cdev->watched_lines); 2313 blocking_notifier_chain_unregister(&gdev->notifier, 2314 &cdev->lineinfo_changed_nb); 2315 put_device(&gdev->dev); 2316 kfree(cdev); 2317 2318 return 0; 2319 } 2320 2321 static const struct file_operations gpio_fileops = { 2322 .release = gpio_chrdev_release, 2323 .open = gpio_chrdev_open, 2324 .poll = lineinfo_watch_poll, 2325 .read = lineinfo_watch_read, 2326 .owner = THIS_MODULE, 2327 .llseek = no_llseek, 2328 .unlocked_ioctl = gpio_ioctl, 2329 #ifdef CONFIG_COMPAT 2330 .compat_ioctl = gpio_ioctl_compat, 2331 #endif 2332 }; 2333 2334 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt) 2335 { 2336 int ret; 2337 2338 cdev_init(&gdev->chrdev, &gpio_fileops); 2339 gdev->chrdev.owner = THIS_MODULE; 2340 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id); 2341 2342 ret = cdev_device_add(&gdev->chrdev, &gdev->dev); 2343 if (ret) 2344 return ret; 2345 2346 chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n", 2347 MAJOR(devt), gdev->id); 2348 2349 return 0; 2350 } 2351 2352 void gpiolib_cdev_unregister(struct gpio_device *gdev) 2353 { 2354 cdev_device_del(&gdev->chrdev, &gdev->dev); 2355 } 2356