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 */ 36static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2)); 37static_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 */ 42static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8)); 43static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8)); 44static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8)); 45static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8)); 46static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8)); 47static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8)); 48static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8)); 49static_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 */ 69struct 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 86static 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 134static 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 150static 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 193static 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 unsigned int i; 201 int ret; 202 203 if (!lh->gdev->chip) 204 return -ENODEV; 205 206 switch (cmd) { 207 case GPIOHANDLE_GET_LINE_VALUES_IOCTL: 208 /* NOTE: It's okay to read values of output lines */ 209 ret = gpiod_get_array_value_complex(false, true, 210 lh->num_descs, lh->descs, 211 NULL, vals); 212 if (ret) 213 return ret; 214 215 memset(&ghd, 0, sizeof(ghd)); 216 for (i = 0; i < lh->num_descs; i++) 217 ghd.values[i] = test_bit(i, vals); 218 219 if (copy_to_user(ip, &ghd, sizeof(ghd))) 220 return -EFAULT; 221 222 return 0; 223 case GPIOHANDLE_SET_LINE_VALUES_IOCTL: 224 /* 225 * All line descriptors were created at once with the same 226 * flags so just check if the first one is really output. 227 */ 228 if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags)) 229 return -EPERM; 230 231 if (copy_from_user(&ghd, ip, sizeof(ghd))) 232 return -EFAULT; 233 234 /* Clamp all values to [0,1] */ 235 for (i = 0; i < lh->num_descs; i++) 236 __assign_bit(i, vals, ghd.values[i]); 237 238 /* Reuse the array setting function */ 239 return gpiod_set_array_value_complex(false, 240 true, 241 lh->num_descs, 242 lh->descs, 243 NULL, 244 vals); 245 case GPIOHANDLE_SET_CONFIG_IOCTL: 246 return linehandle_set_config(lh, ip); 247 default: 248 return -EINVAL; 249 } 250} 251 252#ifdef CONFIG_COMPAT 253static long linehandle_ioctl_compat(struct file *file, unsigned int cmd, 254 unsigned long arg) 255{ 256 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 257} 258#endif 259 260static void linehandle_free(struct linehandle_state *lh) 261{ 262 int i; 263 264 for (i = 0; i < lh->num_descs; i++) 265 if (lh->descs[i]) 266 gpiod_free(lh->descs[i]); 267 kfree(lh->label); 268 put_device(&lh->gdev->dev); 269 kfree(lh); 270} 271 272static int linehandle_release(struct inode *inode, struct file *file) 273{ 274 linehandle_free(file->private_data); 275 return 0; 276} 277 278static const struct file_operations linehandle_fileops = { 279 .release = linehandle_release, 280 .owner = THIS_MODULE, 281 .llseek = noop_llseek, 282 .unlocked_ioctl = linehandle_ioctl, 283#ifdef CONFIG_COMPAT 284 .compat_ioctl = linehandle_ioctl_compat, 285#endif 286}; 287 288static int linehandle_create(struct gpio_device *gdev, void __user *ip) 289{ 290 struct gpiohandle_request handlereq; 291 struct linehandle_state *lh; 292 struct file *file; 293 int fd, i, ret; 294 u32 lflags; 295 296 if (copy_from_user(&handlereq, ip, sizeof(handlereq))) 297 return -EFAULT; 298 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX)) 299 return -EINVAL; 300 301 lflags = handlereq.flags; 302 303 ret = linehandle_validate_flags(lflags); 304 if (ret) 305 return ret; 306 307 lh = kzalloc(sizeof(*lh), GFP_KERNEL); 308 if (!lh) 309 return -ENOMEM; 310 lh->gdev = gdev; 311 get_device(&gdev->dev); 312 313 if (handlereq.consumer_label[0] != '\0') { 314 /* label is only initialized if consumer_label is set */ 315 lh->label = kstrndup(handlereq.consumer_label, 316 sizeof(handlereq.consumer_label) - 1, 317 GFP_KERNEL); 318 if (!lh->label) { 319 ret = -ENOMEM; 320 goto out_free_lh; 321 } 322 } 323 324 lh->num_descs = handlereq.lines; 325 326 /* Request each GPIO */ 327 for (i = 0; i < handlereq.lines; i++) { 328 u32 offset = handlereq.lineoffsets[i]; 329 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset); 330 331 if (IS_ERR(desc)) { 332 ret = PTR_ERR(desc); 333 goto out_free_lh; 334 } 335 336 ret = gpiod_request(desc, lh->label); 337 if (ret) 338 goto out_free_lh; 339 lh->descs[i] = desc; 340 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags); 341 342 ret = gpiod_set_transitory(desc, false); 343 if (ret < 0) 344 goto out_free_lh; 345 346 /* 347 * Lines have to be requested explicitly for input 348 * or output, else the line will be treated "as is". 349 */ 350 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { 351 int val = !!handlereq.default_values[i]; 352 353 ret = gpiod_direction_output(desc, val); 354 if (ret) 355 goto out_free_lh; 356 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { 357 ret = gpiod_direction_input(desc); 358 if (ret) 359 goto out_free_lh; 360 } 361 362 blocking_notifier_call_chain(&desc->gdev->notifier, 363 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 364 365 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 366 offset); 367 } 368 369 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 370 if (fd < 0) { 371 ret = fd; 372 goto out_free_lh; 373 } 374 375 file = anon_inode_getfile("gpio-linehandle", 376 &linehandle_fileops, 377 lh, 378 O_RDONLY | O_CLOEXEC); 379 if (IS_ERR(file)) { 380 ret = PTR_ERR(file); 381 goto out_put_unused_fd; 382 } 383 384 handlereq.fd = fd; 385 if (copy_to_user(ip, &handlereq, sizeof(handlereq))) { 386 /* 387 * fput() will trigger the release() callback, so do not go onto 388 * the regular error cleanup path here. 389 */ 390 fput(file); 391 put_unused_fd(fd); 392 return -EFAULT; 393 } 394 395 fd_install(fd, file); 396 397 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 398 lh->num_descs); 399 400 return 0; 401 402out_put_unused_fd: 403 put_unused_fd(fd); 404out_free_lh: 405 linehandle_free(lh); 406 return ret; 407} 408#endif /* CONFIG_GPIO_CDEV_V1 */ 409 410/** 411 * struct line - contains the state of a requested line 412 * @desc: the GPIO descriptor for this line. 413 * @req: the corresponding line request 414 * @irq: the interrupt triggered in response to events on this GPIO 415 * @eflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or 416 * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied 417 * @timestamp_ns: cache for the timestamp storing it between hardirq and 418 * IRQ thread, used to bring the timestamp close to the actual event 419 * @req_seqno: the seqno for the current edge event in the sequence of 420 * events for the corresponding line request. This is drawn from the @req. 421 * @line_seqno: the seqno for the current edge event in the sequence of 422 * events for this line. 423 * @work: the worker that implements software debouncing 424 * @sw_debounced: flag indicating if the software debouncer is active 425 * @level: the current debounced physical level of the line 426 */ 427struct line { 428 struct gpio_desc *desc; 429 /* 430 * -- edge detector specific fields -- 431 */ 432 struct linereq *req; 433 unsigned int irq; 434 u64 eflags; 435 /* 436 * timestamp_ns and req_seqno are accessed only by 437 * edge_irq_handler() and edge_irq_thread(), which are themselves 438 * mutually exclusive, so no additional protection is necessary. 439 */ 440 u64 timestamp_ns; 441 u32 req_seqno; 442 /* 443 * line_seqno is accessed by either edge_irq_thread() or 444 * debounce_work_func(), which are themselves mutually exclusive, 445 * so no additional protection is necessary. 446 */ 447 u32 line_seqno; 448 /* 449 * -- debouncer specific fields -- 450 */ 451 struct delayed_work work; 452 /* 453 * sw_debounce is accessed by linereq_set_config(), which is the 454 * only setter, and linereq_get_values(), which can live with a 455 * slightly stale value. 456 */ 457 unsigned int sw_debounced; 458 /* 459 * level is accessed by debounce_work_func(), which is the only 460 * setter, and linereq_get_values() which can live with a slightly 461 * stale value. 462 */ 463 unsigned int level; 464}; 465 466/** 467 * struct linereq - contains the state of a userspace line request 468 * @gdev: the GPIO device the line request pertains to 469 * @label: consumer label used to tag GPIO descriptors 470 * @num_lines: the number of lines in the lines array 471 * @wait: wait queue that handles blocking reads of events 472 * @event_buffer_size: the number of elements allocated in @events 473 * @events: KFIFO for the GPIO events 474 * @seqno: the sequence number for edge events generated on all lines in 475 * this line request. Note that this is not used when @num_lines is 1, as 476 * the line_seqno is then the same and is cheaper to calculate. 477 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency 478 * of configuration, particularly multi-step accesses to desc flags. 479 * @lines: the lines held by this line request, with @num_lines elements. 480 */ 481struct linereq { 482 struct gpio_device *gdev; 483 const char *label; 484 u32 num_lines; 485 wait_queue_head_t wait; 486 u32 event_buffer_size; 487 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event); 488 atomic_t seqno; 489 struct mutex config_mutex; 490 struct line lines[]; 491}; 492 493#define GPIO_V2_LINE_BIAS_FLAGS \ 494 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \ 495 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \ 496 GPIO_V2_LINE_FLAG_BIAS_DISABLED) 497 498#define GPIO_V2_LINE_DIRECTION_FLAGS \ 499 (GPIO_V2_LINE_FLAG_INPUT | \ 500 GPIO_V2_LINE_FLAG_OUTPUT) 501 502#define GPIO_V2_LINE_DRIVE_FLAGS \ 503 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \ 504 GPIO_V2_LINE_FLAG_OPEN_SOURCE) 505 506#define GPIO_V2_LINE_EDGE_FLAGS \ 507 (GPIO_V2_LINE_FLAG_EDGE_RISING | \ 508 GPIO_V2_LINE_FLAG_EDGE_FALLING) 509 510#define GPIO_V2_LINE_VALID_FLAGS \ 511 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ 512 GPIO_V2_LINE_DIRECTION_FLAGS | \ 513 GPIO_V2_LINE_DRIVE_FLAGS | \ 514 GPIO_V2_LINE_EDGE_FLAGS | \ 515 GPIO_V2_LINE_BIAS_FLAGS) 516 517static void linereq_put_event(struct linereq *lr, 518 struct gpio_v2_line_event *le) 519{ 520 bool overflow = false; 521 522 spin_lock(&lr->wait.lock); 523 if (kfifo_is_full(&lr->events)) { 524 overflow = true; 525 kfifo_skip(&lr->events); 526 } 527 kfifo_in(&lr->events, le, 1); 528 spin_unlock(&lr->wait.lock); 529 if (!overflow) 530 wake_up_poll(&lr->wait, EPOLLIN); 531 else 532 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 533} 534 535static irqreturn_t edge_irq_thread(int irq, void *p) 536{ 537 struct line *line = p; 538 struct linereq *lr = line->req; 539 struct gpio_v2_line_event le; 540 541 /* Do not leak kernel stack to userspace */ 542 memset(&le, 0, sizeof(le)); 543 544 if (line->timestamp_ns) { 545 le.timestamp_ns = line->timestamp_ns; 546 } else { 547 /* 548 * We may be running from a nested threaded interrupt in 549 * which case we didn't get the timestamp from 550 * edge_irq_handler(). 551 */ 552 le.timestamp_ns = ktime_get_ns(); 553 if (lr->num_lines != 1) 554 line->req_seqno = atomic_inc_return(&lr->seqno); 555 } 556 line->timestamp_ns = 0; 557 558 if (line->eflags == (GPIO_V2_LINE_FLAG_EDGE_RISING | 559 GPIO_V2_LINE_FLAG_EDGE_FALLING)) { 560 int level = gpiod_get_value_cansleep(line->desc); 561 562 if (level) 563 /* Emit low-to-high event */ 564 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 565 else 566 /* Emit high-to-low event */ 567 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 568 } else if (line->eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) { 569 /* Emit low-to-high event */ 570 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 571 } else if (line->eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) { 572 /* Emit high-to-low event */ 573 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 574 } else { 575 return IRQ_NONE; 576 } 577 line->line_seqno++; 578 le.line_seqno = line->line_seqno; 579 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno; 580 le.offset = gpio_chip_hwgpio(line->desc); 581 582 linereq_put_event(lr, &le); 583 584 return IRQ_HANDLED; 585} 586 587static irqreturn_t edge_irq_handler(int irq, void *p) 588{ 589 struct line *line = p; 590 struct linereq *lr = line->req; 591 592 /* 593 * Just store the timestamp in hardirq context so we get it as 594 * close in time as possible to the actual event. 595 */ 596 line->timestamp_ns = ktime_get_ns(); 597 598 if (lr->num_lines != 1) 599 line->req_seqno = atomic_inc_return(&lr->seqno); 600 601 return IRQ_WAKE_THREAD; 602} 603 604/* 605 * returns the current debounced logical value. 606 */ 607static bool debounced_value(struct line *line) 608{ 609 bool value; 610 611 /* 612 * minor race - debouncer may be stopped here, so edge_detector_stop() 613 * must leave the value unchanged so the following will read the level 614 * from when the debouncer was last running. 615 */ 616 value = READ_ONCE(line->level); 617 618 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags)) 619 value = !value; 620 621 return value; 622} 623 624static irqreturn_t debounce_irq_handler(int irq, void *p) 625{ 626 struct line *line = p; 627 628 mod_delayed_work(system_wq, &line->work, 629 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); 630 631 return IRQ_HANDLED; 632} 633 634static void debounce_work_func(struct work_struct *work) 635{ 636 struct gpio_v2_line_event le; 637 struct line *line = container_of(work, struct line, work.work); 638 struct linereq *lr; 639 int level; 640 641 level = gpiod_get_raw_value_cansleep(line->desc); 642 if (level < 0) { 643 pr_debug_ratelimited("debouncer failed to read line value\n"); 644 return; 645 } 646 647 if (READ_ONCE(line->level) == level) 648 return; 649 650 WRITE_ONCE(line->level, level); 651 652 /* -- edge detection -- */ 653 if (!line->eflags) 654 return; 655 656 /* switch from physical level to logical - if they differ */ 657 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags)) 658 level = !level; 659 660 /* ignore edges that are not being monitored */ 661 if (((line->eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) || 662 ((line->eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level)) 663 return; 664 665 /* Do not leak kernel stack to userspace */ 666 memset(&le, 0, sizeof(le)); 667 668 lr = line->req; 669 le.timestamp_ns = ktime_get_ns(); 670 le.offset = gpio_chip_hwgpio(line->desc); 671 line->line_seqno++; 672 le.line_seqno = line->line_seqno; 673 le.seqno = (lr->num_lines == 1) ? 674 le.line_seqno : atomic_inc_return(&lr->seqno); 675 676 if (level) 677 /* Emit low-to-high event */ 678 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 679 else 680 /* Emit high-to-low event */ 681 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 682 683 linereq_put_event(lr, &le); 684} 685 686static int debounce_setup(struct line *line, 687 unsigned int debounce_period_us) 688{ 689 unsigned long irqflags; 690 int ret, level, irq; 691 692 /* try hardware */ 693 ret = gpiod_set_debounce(line->desc, debounce_period_us); 694 if (!ret) { 695 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 696 return ret; 697 } 698 if (ret != -ENOTSUPP) 699 return ret; 700 701 if (debounce_period_us) { 702 /* setup software debounce */ 703 level = gpiod_get_raw_value_cansleep(line->desc); 704 if (level < 0) 705 return level; 706 707 irq = gpiod_to_irq(line->desc); 708 if (irq < 0) 709 return -ENXIO; 710 711 WRITE_ONCE(line->level, level); 712 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING; 713 ret = request_irq(irq, debounce_irq_handler, irqflags, 714 line->req->label, line); 715 if (ret) 716 return ret; 717 718 WRITE_ONCE(line->sw_debounced, 1); 719 line->irq = irq; 720 } 721 return 0; 722} 723 724static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc, 725 unsigned int line_idx) 726{ 727 unsigned int i; 728 u64 mask = BIT_ULL(line_idx); 729 730 for (i = 0; i < lc->num_attrs; i++) { 731 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 732 (lc->attrs[i].mask & mask)) 733 return true; 734 } 735 return false; 736} 737 738static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc, 739 unsigned int line_idx) 740{ 741 unsigned int i; 742 u64 mask = BIT_ULL(line_idx); 743 744 for (i = 0; i < lc->num_attrs; i++) { 745 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 746 (lc->attrs[i].mask & mask)) 747 return lc->attrs[i].attr.debounce_period_us; 748 } 749 return 0; 750} 751 752static void edge_detector_stop(struct line *line) 753{ 754 if (line->irq) { 755 free_irq(line->irq, line); 756 line->irq = 0; 757 } 758 759 cancel_delayed_work_sync(&line->work); 760 WRITE_ONCE(line->sw_debounced, 0); 761 line->eflags = 0; 762 if (line->desc) 763 WRITE_ONCE(line->desc->debounce_period_us, 0); 764 /* do not change line->level - see comment in debounced_value() */ 765} 766 767static int edge_detector_setup(struct line *line, 768 struct gpio_v2_line_config *lc, 769 unsigned int line_idx, 770 u64 eflags) 771{ 772 u32 debounce_period_us; 773 unsigned long irqflags = 0; 774 int irq, ret; 775 776 if (eflags && !kfifo_initialized(&line->req->events)) { 777 ret = kfifo_alloc(&line->req->events, 778 line->req->event_buffer_size, GFP_KERNEL); 779 if (ret) 780 return ret; 781 } 782 line->eflags = eflags; 783 if (gpio_v2_line_config_debounced(lc, line_idx)) { 784 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx); 785 ret = debounce_setup(line, debounce_period_us); 786 if (ret) 787 return ret; 788 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 789 } 790 791 /* detection disabled or sw debouncer will provide edge detection */ 792 if (!eflags || READ_ONCE(line->sw_debounced)) 793 return 0; 794 795 irq = gpiod_to_irq(line->desc); 796 if (irq < 0) 797 return -ENXIO; 798 799 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING) 800 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 801 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 802 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING) 803 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 804 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 805 irqflags |= IRQF_ONESHOT; 806 807 /* Request a thread to read the events */ 808 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread, 809 irqflags, line->req->label, line); 810 if (ret) 811 return ret; 812 813 line->irq = irq; 814 return 0; 815} 816 817static int edge_detector_update(struct line *line, 818 struct gpio_v2_line_config *lc, 819 unsigned int line_idx, 820 u64 eflags, bool polarity_change) 821{ 822 unsigned int debounce_period_us = 823 gpio_v2_line_config_debounce_period(lc, line_idx); 824 825 if ((line->eflags == eflags) && !polarity_change && 826 (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us)) 827 return 0; 828 829 /* sw debounced and still will be...*/ 830 if (debounce_period_us && READ_ONCE(line->sw_debounced)) { 831 line->eflags = eflags; 832 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 833 return 0; 834 } 835 836 /* reconfiguring edge detection or sw debounce being disabled */ 837 if ((line->irq && !READ_ONCE(line->sw_debounced)) || 838 (!debounce_period_us && READ_ONCE(line->sw_debounced))) 839 edge_detector_stop(line); 840 841 return edge_detector_setup(line, lc, line_idx, eflags); 842} 843 844static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc, 845 unsigned int line_idx) 846{ 847 unsigned int i; 848 u64 mask = BIT_ULL(line_idx); 849 850 for (i = 0; i < lc->num_attrs; i++) { 851 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) && 852 (lc->attrs[i].mask & mask)) 853 return lc->attrs[i].attr.flags; 854 } 855 return lc->flags; 856} 857 858static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc, 859 unsigned int line_idx) 860{ 861 unsigned int i; 862 u64 mask = BIT_ULL(line_idx); 863 864 for (i = 0; i < lc->num_attrs; i++) { 865 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) && 866 (lc->attrs[i].mask & mask)) 867 return !!(lc->attrs[i].attr.values & mask); 868 } 869 return 0; 870} 871 872static int gpio_v2_line_flags_validate(u64 flags) 873{ 874 /* Return an error if an unknown flag is set */ 875 if (flags & ~GPIO_V2_LINE_VALID_FLAGS) 876 return -EINVAL; 877 878 /* 879 * Do not allow both INPUT and OUTPUT flags to be set as they are 880 * contradictory. 881 */ 882 if ((flags & GPIO_V2_LINE_FLAG_INPUT) && 883 (flags & GPIO_V2_LINE_FLAG_OUTPUT)) 884 return -EINVAL; 885 886 /* Edge detection requires explicit input. */ 887 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) && 888 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 889 return -EINVAL; 890 891 /* 892 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single 893 * request. If the hardware actually supports enabling both at the 894 * same time the electrical result would be disastrous. 895 */ 896 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) && 897 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE)) 898 return -EINVAL; 899 900 /* Drive requires explicit output direction. */ 901 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) && 902 !(flags & GPIO_V2_LINE_FLAG_OUTPUT)) 903 return -EINVAL; 904 905 /* Bias requires explicit direction. */ 906 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) && 907 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS)) 908 return -EINVAL; 909 910 /* Only one bias flag can be set. */ 911 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) && 912 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | 913 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) || 914 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) && 915 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) 916 return -EINVAL; 917 918 return 0; 919} 920 921static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc, 922 unsigned int num_lines) 923{ 924 unsigned int i; 925 u64 flags; 926 int ret; 927 928 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX) 929 return -EINVAL; 930 931 if (memchr_inv(lc->padding, 0, sizeof(lc->padding))) 932 return -EINVAL; 933 934 for (i = 0; i < num_lines; i++) { 935 flags = gpio_v2_line_config_flags(lc, i); 936 ret = gpio_v2_line_flags_validate(flags); 937 if (ret) 938 return ret; 939 940 /* debounce requires explicit input */ 941 if (gpio_v2_line_config_debounced(lc, i) && 942 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 943 return -EINVAL; 944 } 945 return 0; 946} 947 948static void gpio_v2_line_config_flags_to_desc_flags(u64 flags, 949 unsigned long *flagsp) 950{ 951 assign_bit(FLAG_ACTIVE_LOW, flagsp, 952 flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW); 953 954 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) 955 set_bit(FLAG_IS_OUT, flagsp); 956 else if (flags & GPIO_V2_LINE_FLAG_INPUT) 957 clear_bit(FLAG_IS_OUT, flagsp); 958 959 assign_bit(FLAG_EDGE_RISING, flagsp, 960 flags & GPIO_V2_LINE_FLAG_EDGE_RISING); 961 assign_bit(FLAG_EDGE_FALLING, flagsp, 962 flags & GPIO_V2_LINE_FLAG_EDGE_FALLING); 963 964 assign_bit(FLAG_OPEN_DRAIN, flagsp, 965 flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN); 966 assign_bit(FLAG_OPEN_SOURCE, flagsp, 967 flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE); 968 969 assign_bit(FLAG_PULL_UP, flagsp, 970 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP); 971 assign_bit(FLAG_PULL_DOWN, flagsp, 972 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN); 973 assign_bit(FLAG_BIAS_DISABLE, flagsp, 974 flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED); 975} 976 977static long linereq_get_values(struct linereq *lr, void __user *ip) 978{ 979 struct gpio_v2_line_values lv; 980 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 981 struct gpio_desc **descs; 982 unsigned int i, didx, num_get; 983 bool val; 984 int ret; 985 986 /* NOTE: It's ok to read values of output lines. */ 987 if (copy_from_user(&lv, ip, sizeof(lv))) 988 return -EFAULT; 989 990 for (num_get = 0, i = 0; i < lr->num_lines; i++) { 991 if (lv.mask & BIT_ULL(i)) { 992 num_get++; 993 descs = &lr->lines[i].desc; 994 } 995 } 996 997 if (num_get == 0) 998 return -EINVAL; 999 1000 if (num_get != 1) { 1001 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL); 1002 if (!descs) 1003 return -ENOMEM; 1004 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1005 if (lv.mask & BIT_ULL(i)) { 1006 descs[didx] = lr->lines[i].desc; 1007 didx++; 1008 } 1009 } 1010 } 1011 ret = gpiod_get_array_value_complex(false, true, num_get, 1012 descs, NULL, vals); 1013 1014 if (num_get != 1) 1015 kfree(descs); 1016 if (ret) 1017 return ret; 1018 1019 lv.bits = 0; 1020 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1021 if (lv.mask & BIT_ULL(i)) { 1022 if (lr->lines[i].sw_debounced) 1023 val = debounced_value(&lr->lines[i]); 1024 else 1025 val = test_bit(didx, vals); 1026 if (val) 1027 lv.bits |= BIT_ULL(i); 1028 didx++; 1029 } 1030 } 1031 1032 if (copy_to_user(ip, &lv, sizeof(lv))) 1033 return -EFAULT; 1034 1035 return 0; 1036} 1037 1038static long linereq_set_values_unlocked(struct linereq *lr, 1039 struct gpio_v2_line_values *lv) 1040{ 1041 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1042 struct gpio_desc **descs; 1043 unsigned int i, didx, num_set; 1044 int ret; 1045 1046 bitmap_zero(vals, GPIO_V2_LINES_MAX); 1047 for (num_set = 0, i = 0; i < lr->num_lines; i++) { 1048 if (lv->mask & BIT_ULL(i)) { 1049 if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags)) 1050 return -EPERM; 1051 if (lv->bits & BIT_ULL(i)) 1052 __set_bit(num_set, vals); 1053 num_set++; 1054 descs = &lr->lines[i].desc; 1055 } 1056 } 1057 if (num_set == 0) 1058 return -EINVAL; 1059 1060 if (num_set != 1) { 1061 /* build compacted desc array and values */ 1062 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL); 1063 if (!descs) 1064 return -ENOMEM; 1065 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1066 if (lv->mask & BIT_ULL(i)) { 1067 descs[didx] = lr->lines[i].desc; 1068 didx++; 1069 } 1070 } 1071 } 1072 ret = gpiod_set_array_value_complex(false, true, num_set, 1073 descs, NULL, vals); 1074 1075 if (num_set != 1) 1076 kfree(descs); 1077 return ret; 1078} 1079 1080static long linereq_set_values(struct linereq *lr, void __user *ip) 1081{ 1082 struct gpio_v2_line_values lv; 1083 int ret; 1084 1085 if (copy_from_user(&lv, ip, sizeof(lv))) 1086 return -EFAULT; 1087 1088 mutex_lock(&lr->config_mutex); 1089 1090 ret = linereq_set_values_unlocked(lr, &lv); 1091 1092 mutex_unlock(&lr->config_mutex); 1093 1094 return ret; 1095} 1096 1097static long linereq_set_config_unlocked(struct linereq *lr, 1098 struct gpio_v2_line_config *lc) 1099{ 1100 struct gpio_desc *desc; 1101 unsigned int i; 1102 u64 flags; 1103 bool polarity_change; 1104 int ret; 1105 1106 for (i = 0; i < lr->num_lines; i++) { 1107 desc = lr->lines[i].desc; 1108 flags = gpio_v2_line_config_flags(lc, i); 1109 polarity_change = 1110 (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) != 1111 ((flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) != 0)); 1112 1113 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1114 /* 1115 * Lines have to be requested explicitly for input 1116 * or output, else the line will be treated "as is". 1117 */ 1118 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1119 int val = gpio_v2_line_config_output_value(lc, i); 1120 1121 edge_detector_stop(&lr->lines[i]); 1122 ret = gpiod_direction_output(desc, val); 1123 if (ret) 1124 return ret; 1125 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1126 ret = gpiod_direction_input(desc); 1127 if (ret) 1128 return ret; 1129 1130 ret = edge_detector_update(&lr->lines[i], lc, i, 1131 flags & GPIO_V2_LINE_EDGE_FLAGS, 1132 polarity_change); 1133 if (ret) 1134 return ret; 1135 } 1136 1137 blocking_notifier_call_chain(&desc->gdev->notifier, 1138 GPIO_V2_LINE_CHANGED_CONFIG, 1139 desc); 1140 } 1141 return 0; 1142} 1143 1144static long linereq_set_config(struct linereq *lr, void __user *ip) 1145{ 1146 struct gpio_v2_line_config lc; 1147 int ret; 1148 1149 if (copy_from_user(&lc, ip, sizeof(lc))) 1150 return -EFAULT; 1151 1152 ret = gpio_v2_line_config_validate(&lc, lr->num_lines); 1153 if (ret) 1154 return ret; 1155 1156 mutex_lock(&lr->config_mutex); 1157 1158 ret = linereq_set_config_unlocked(lr, &lc); 1159 1160 mutex_unlock(&lr->config_mutex); 1161 1162 return ret; 1163} 1164 1165static long linereq_ioctl(struct file *file, unsigned int cmd, 1166 unsigned long arg) 1167{ 1168 struct linereq *lr = file->private_data; 1169 void __user *ip = (void __user *)arg; 1170 1171 if (!lr->gdev->chip) 1172 return -ENODEV; 1173 1174 switch (cmd) { 1175 case GPIO_V2_LINE_GET_VALUES_IOCTL: 1176 return linereq_get_values(lr, ip); 1177 case GPIO_V2_LINE_SET_VALUES_IOCTL: 1178 return linereq_set_values(lr, ip); 1179 case GPIO_V2_LINE_SET_CONFIG_IOCTL: 1180 return linereq_set_config(lr, ip); 1181 default: 1182 return -EINVAL; 1183 } 1184} 1185 1186#ifdef CONFIG_COMPAT 1187static long linereq_ioctl_compat(struct file *file, unsigned int cmd, 1188 unsigned long arg) 1189{ 1190 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1191} 1192#endif 1193 1194static __poll_t linereq_poll(struct file *file, 1195 struct poll_table_struct *wait) 1196{ 1197 struct linereq *lr = file->private_data; 1198 __poll_t events = 0; 1199 1200 if (!lr->gdev->chip) 1201 return EPOLLHUP | EPOLLERR; 1202 1203 poll_wait(file, &lr->wait, wait); 1204 1205 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events, 1206 &lr->wait.lock)) 1207 events = EPOLLIN | EPOLLRDNORM; 1208 1209 return events; 1210} 1211 1212static ssize_t linereq_read(struct file *file, 1213 char __user *buf, 1214 size_t count, 1215 loff_t *f_ps) 1216{ 1217 struct linereq *lr = file->private_data; 1218 struct gpio_v2_line_event le; 1219 ssize_t bytes_read = 0; 1220 int ret; 1221 1222 if (!lr->gdev->chip) 1223 return -ENODEV; 1224 1225 if (count < sizeof(le)) 1226 return -EINVAL; 1227 1228 do { 1229 spin_lock(&lr->wait.lock); 1230 if (kfifo_is_empty(&lr->events)) { 1231 if (bytes_read) { 1232 spin_unlock(&lr->wait.lock); 1233 return bytes_read; 1234 } 1235 1236 if (file->f_flags & O_NONBLOCK) { 1237 spin_unlock(&lr->wait.lock); 1238 return -EAGAIN; 1239 } 1240 1241 ret = wait_event_interruptible_locked(lr->wait, 1242 !kfifo_is_empty(&lr->events)); 1243 if (ret) { 1244 spin_unlock(&lr->wait.lock); 1245 return ret; 1246 } 1247 } 1248 1249 ret = kfifo_out(&lr->events, &le, 1); 1250 spin_unlock(&lr->wait.lock); 1251 if (ret != 1) { 1252 /* 1253 * This should never happen - we were holding the 1254 * lock from the moment we learned the fifo is no 1255 * longer empty until now. 1256 */ 1257 ret = -EIO; 1258 break; 1259 } 1260 1261 if (copy_to_user(buf + bytes_read, &le, sizeof(le))) 1262 return -EFAULT; 1263 bytes_read += sizeof(le); 1264 } while (count >= bytes_read + sizeof(le)); 1265 1266 return bytes_read; 1267} 1268 1269static void linereq_free(struct linereq *lr) 1270{ 1271 unsigned int i; 1272 1273 for (i = 0; i < lr->num_lines; i++) { 1274 edge_detector_stop(&lr->lines[i]); 1275 if (lr->lines[i].desc) 1276 gpiod_free(lr->lines[i].desc); 1277 } 1278 kfifo_free(&lr->events); 1279 kfree(lr->label); 1280 put_device(&lr->gdev->dev); 1281 kfree(lr); 1282} 1283 1284static int linereq_release(struct inode *inode, struct file *file) 1285{ 1286 struct linereq *lr = file->private_data; 1287 1288 linereq_free(lr); 1289 return 0; 1290} 1291 1292static const struct file_operations line_fileops = { 1293 .release = linereq_release, 1294 .read = linereq_read, 1295 .poll = linereq_poll, 1296 .owner = THIS_MODULE, 1297 .llseek = noop_llseek, 1298 .unlocked_ioctl = linereq_ioctl, 1299#ifdef CONFIG_COMPAT 1300 .compat_ioctl = linereq_ioctl_compat, 1301#endif 1302}; 1303 1304static int linereq_create(struct gpio_device *gdev, void __user *ip) 1305{ 1306 struct gpio_v2_line_request ulr; 1307 struct gpio_v2_line_config *lc; 1308 struct linereq *lr; 1309 struct file *file; 1310 u64 flags; 1311 unsigned int i; 1312 int fd, ret; 1313 1314 if (copy_from_user(&ulr, ip, sizeof(ulr))) 1315 return -EFAULT; 1316 1317 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX)) 1318 return -EINVAL; 1319 1320 if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding))) 1321 return -EINVAL; 1322 1323 lc = &ulr.config; 1324 ret = gpio_v2_line_config_validate(lc, ulr.num_lines); 1325 if (ret) 1326 return ret; 1327 1328 lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL); 1329 if (!lr) 1330 return -ENOMEM; 1331 1332 lr->gdev = gdev; 1333 get_device(&gdev->dev); 1334 1335 for (i = 0; i < ulr.num_lines; i++) { 1336 lr->lines[i].req = lr; 1337 WRITE_ONCE(lr->lines[i].sw_debounced, 0); 1338 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func); 1339 } 1340 1341 if (ulr.consumer[0] != '\0') { 1342 /* label is only initialized if consumer is set */ 1343 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1, 1344 GFP_KERNEL); 1345 if (!lr->label) { 1346 ret = -ENOMEM; 1347 goto out_free_linereq; 1348 } 1349 } 1350 1351 mutex_init(&lr->config_mutex); 1352 init_waitqueue_head(&lr->wait); 1353 lr->event_buffer_size = ulr.event_buffer_size; 1354 if (lr->event_buffer_size == 0) 1355 lr->event_buffer_size = ulr.num_lines * 16; 1356 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16) 1357 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16; 1358 1359 atomic_set(&lr->seqno, 0); 1360 lr->num_lines = ulr.num_lines; 1361 1362 /* Request each GPIO */ 1363 for (i = 0; i < ulr.num_lines; i++) { 1364 u32 offset = ulr.offsets[i]; 1365 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset); 1366 1367 if (IS_ERR(desc)) { 1368 ret = PTR_ERR(desc); 1369 goto out_free_linereq; 1370 } 1371 1372 ret = gpiod_request(desc, lr->label); 1373 if (ret) 1374 goto out_free_linereq; 1375 1376 lr->lines[i].desc = desc; 1377 flags = gpio_v2_line_config_flags(lc, i); 1378 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1379 1380 ret = gpiod_set_transitory(desc, false); 1381 if (ret < 0) 1382 goto out_free_linereq; 1383 1384 /* 1385 * Lines have to be requested explicitly for input 1386 * or output, else the line will be treated "as is". 1387 */ 1388 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1389 int val = gpio_v2_line_config_output_value(lc, i); 1390 1391 ret = gpiod_direction_output(desc, val); 1392 if (ret) 1393 goto out_free_linereq; 1394 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1395 ret = gpiod_direction_input(desc); 1396 if (ret) 1397 goto out_free_linereq; 1398 1399 ret = edge_detector_setup(&lr->lines[i], lc, i, 1400 flags & GPIO_V2_LINE_EDGE_FLAGS); 1401 if (ret) 1402 goto out_free_linereq; 1403 } 1404 1405 blocking_notifier_call_chain(&desc->gdev->notifier, 1406 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 1407 1408 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 1409 offset); 1410 } 1411 1412 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 1413 if (fd < 0) { 1414 ret = fd; 1415 goto out_free_linereq; 1416 } 1417 1418 file = anon_inode_getfile("gpio-line", &line_fileops, lr, 1419 O_RDONLY | O_CLOEXEC); 1420 if (IS_ERR(file)) { 1421 ret = PTR_ERR(file); 1422 goto out_put_unused_fd; 1423 } 1424 1425 ulr.fd = fd; 1426 if (copy_to_user(ip, &ulr, sizeof(ulr))) { 1427 /* 1428 * fput() will trigger the release() callback, so do not go onto 1429 * the regular error cleanup path here. 1430 */ 1431 fput(file); 1432 put_unused_fd(fd); 1433 return -EFAULT; 1434 } 1435 1436 fd_install(fd, file); 1437 1438 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 1439 lr->num_lines); 1440 1441 return 0; 1442 1443out_put_unused_fd: 1444 put_unused_fd(fd); 1445out_free_linereq: 1446 linereq_free(lr); 1447 return ret; 1448} 1449 1450#ifdef CONFIG_GPIO_CDEV_V1 1451 1452/* 1453 * GPIO line event management 1454 */ 1455 1456/** 1457 * struct lineevent_state - contains the state of a userspace event 1458 * @gdev: the GPIO device the event pertains to 1459 * @label: consumer label used to tag descriptors 1460 * @desc: the GPIO descriptor held by this event 1461 * @eflags: the event flags this line was requested with 1462 * @irq: the interrupt that trigger in response to events on this GPIO 1463 * @wait: wait queue that handles blocking reads of events 1464 * @events: KFIFO for the GPIO events 1465 * @timestamp: cache for the timestamp storing it between hardirq 1466 * and IRQ thread, used to bring the timestamp close to the actual 1467 * event 1468 */ 1469struct lineevent_state { 1470 struct gpio_device *gdev; 1471 const char *label; 1472 struct gpio_desc *desc; 1473 u32 eflags; 1474 int irq; 1475 wait_queue_head_t wait; 1476 DECLARE_KFIFO(events, struct gpioevent_data, 16); 1477 u64 timestamp; 1478}; 1479 1480#define GPIOEVENT_REQUEST_VALID_FLAGS \ 1481 (GPIOEVENT_REQUEST_RISING_EDGE | \ 1482 GPIOEVENT_REQUEST_FALLING_EDGE) 1483 1484static __poll_t lineevent_poll(struct file *file, 1485 struct poll_table_struct *wait) 1486{ 1487 struct lineevent_state *le = file->private_data; 1488 __poll_t events = 0; 1489 1490 if (!le->gdev->chip) 1491 return EPOLLHUP | EPOLLERR; 1492 1493 poll_wait(file, &le->wait, wait); 1494 1495 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock)) 1496 events = EPOLLIN | EPOLLRDNORM; 1497 1498 return events; 1499} 1500 1501static ssize_t lineevent_get_size(void) 1502{ 1503#if defined(CONFIG_X86_64) && !defined(CONFIG_UML) 1504 /* i386 has no padding after 'id' */ 1505 if (in_ia32_syscall()) { 1506 struct compat_gpioeevent_data { 1507 compat_u64 timestamp; 1508 u32 id; 1509 }; 1510 1511 return sizeof(struct compat_gpioeevent_data); 1512 } 1513#endif 1514 return sizeof(struct gpioevent_data); 1515} 1516 1517static ssize_t lineevent_read(struct file *file, 1518 char __user *buf, 1519 size_t count, 1520 loff_t *f_ps) 1521{ 1522 struct lineevent_state *le = file->private_data; 1523 struct gpioevent_data ge; 1524 ssize_t bytes_read = 0; 1525 ssize_t ge_size; 1526 int ret; 1527 1528 if (!le->gdev->chip) 1529 return -ENODEV; 1530 1531 /* 1532 * When compatible system call is being used the struct gpioevent_data, 1533 * in case of at least ia32, has different size due to the alignment 1534 * differences. Because we have first member 64 bits followed by one of 1535 * 32 bits there is no gap between them. The only difference is the 1536 * padding at the end of the data structure. Hence, we calculate the 1537 * actual sizeof() and pass this as an argument to copy_to_user() to 1538 * drop unneeded bytes from the output. 1539 */ 1540 ge_size = lineevent_get_size(); 1541 if (count < ge_size) 1542 return -EINVAL; 1543 1544 do { 1545 spin_lock(&le->wait.lock); 1546 if (kfifo_is_empty(&le->events)) { 1547 if (bytes_read) { 1548 spin_unlock(&le->wait.lock); 1549 return bytes_read; 1550 } 1551 1552 if (file->f_flags & O_NONBLOCK) { 1553 spin_unlock(&le->wait.lock); 1554 return -EAGAIN; 1555 } 1556 1557 ret = wait_event_interruptible_locked(le->wait, 1558 !kfifo_is_empty(&le->events)); 1559 if (ret) { 1560 spin_unlock(&le->wait.lock); 1561 return ret; 1562 } 1563 } 1564 1565 ret = kfifo_out(&le->events, &ge, 1); 1566 spin_unlock(&le->wait.lock); 1567 if (ret != 1) { 1568 /* 1569 * This should never happen - we were holding the lock 1570 * from the moment we learned the fifo is no longer 1571 * empty until now. 1572 */ 1573 ret = -EIO; 1574 break; 1575 } 1576 1577 if (copy_to_user(buf + bytes_read, &ge, ge_size)) 1578 return -EFAULT; 1579 bytes_read += ge_size; 1580 } while (count >= bytes_read + ge_size); 1581 1582 return bytes_read; 1583} 1584 1585static void lineevent_free(struct lineevent_state *le) 1586{ 1587 if (le->irq) 1588 free_irq(le->irq, le); 1589 if (le->desc) 1590 gpiod_free(le->desc); 1591 kfree(le->label); 1592 put_device(&le->gdev->dev); 1593 kfree(le); 1594} 1595 1596static int lineevent_release(struct inode *inode, struct file *file) 1597{ 1598 lineevent_free(file->private_data); 1599 return 0; 1600} 1601 1602static long lineevent_ioctl(struct file *file, unsigned int cmd, 1603 unsigned long arg) 1604{ 1605 struct lineevent_state *le = file->private_data; 1606 void __user *ip = (void __user *)arg; 1607 struct gpiohandle_data ghd; 1608 1609 if (!le->gdev->chip) 1610 return -ENODEV; 1611 1612 /* 1613 * We can get the value for an event line but not set it, 1614 * because it is input by definition. 1615 */ 1616 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { 1617 int val; 1618 1619 memset(&ghd, 0, sizeof(ghd)); 1620 1621 val = gpiod_get_value_cansleep(le->desc); 1622 if (val < 0) 1623 return val; 1624 ghd.values[0] = val; 1625 1626 if (copy_to_user(ip, &ghd, sizeof(ghd))) 1627 return -EFAULT; 1628 1629 return 0; 1630 } 1631 return -EINVAL; 1632} 1633 1634#ifdef CONFIG_COMPAT 1635static long lineevent_ioctl_compat(struct file *file, unsigned int cmd, 1636 unsigned long arg) 1637{ 1638 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1639} 1640#endif 1641 1642static const struct file_operations lineevent_fileops = { 1643 .release = lineevent_release, 1644 .read = lineevent_read, 1645 .poll = lineevent_poll, 1646 .owner = THIS_MODULE, 1647 .llseek = noop_llseek, 1648 .unlocked_ioctl = lineevent_ioctl, 1649#ifdef CONFIG_COMPAT 1650 .compat_ioctl = lineevent_ioctl_compat, 1651#endif 1652}; 1653 1654static irqreturn_t lineevent_irq_thread(int irq, void *p) 1655{ 1656 struct lineevent_state *le = p; 1657 struct gpioevent_data ge; 1658 int ret; 1659 1660 /* Do not leak kernel stack to userspace */ 1661 memset(&ge, 0, sizeof(ge)); 1662 1663 /* 1664 * We may be running from a nested threaded interrupt in which case 1665 * we didn't get the timestamp from lineevent_irq_handler(). 1666 */ 1667 if (!le->timestamp) 1668 ge.timestamp = ktime_get_ns(); 1669 else 1670 ge.timestamp = le->timestamp; 1671 1672 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE 1673 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 1674 int level = gpiod_get_value_cansleep(le->desc); 1675 1676 if (level) 1677 /* Emit low-to-high event */ 1678 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 1679 else 1680 /* Emit high-to-low event */ 1681 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 1682 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) { 1683 /* Emit low-to-high event */ 1684 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 1685 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 1686 /* Emit high-to-low event */ 1687 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 1688 } else { 1689 return IRQ_NONE; 1690 } 1691 1692 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge, 1693 1, &le->wait.lock); 1694 if (ret) 1695 wake_up_poll(&le->wait, EPOLLIN); 1696 else 1697 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 1698 1699 return IRQ_HANDLED; 1700} 1701 1702static irqreturn_t lineevent_irq_handler(int irq, void *p) 1703{ 1704 struct lineevent_state *le = p; 1705 1706 /* 1707 * Just store the timestamp in hardirq context so we get it as 1708 * close in time as possible to the actual event. 1709 */ 1710 le->timestamp = ktime_get_ns(); 1711 1712 return IRQ_WAKE_THREAD; 1713} 1714 1715static int lineevent_create(struct gpio_device *gdev, void __user *ip) 1716{ 1717 struct gpioevent_request eventreq; 1718 struct lineevent_state *le; 1719 struct gpio_desc *desc; 1720 struct file *file; 1721 u32 offset; 1722 u32 lflags; 1723 u32 eflags; 1724 int fd; 1725 int ret; 1726 int irq, irqflags = 0; 1727 1728 if (copy_from_user(&eventreq, ip, sizeof(eventreq))) 1729 return -EFAULT; 1730 1731 offset = eventreq.lineoffset; 1732 lflags = eventreq.handleflags; 1733 eflags = eventreq.eventflags; 1734 1735 desc = gpiochip_get_desc(gdev->chip, offset); 1736 if (IS_ERR(desc)) 1737 return PTR_ERR(desc); 1738 1739 /* Return an error if a unknown flag is set */ 1740 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) || 1741 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS)) 1742 return -EINVAL; 1743 1744 /* This is just wrong: we don't look for events on output lines */ 1745 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) || 1746 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 1747 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 1748 return -EINVAL; 1749 1750 /* Only one bias flag can be set. */ 1751 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 1752 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 1753 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 1754 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 1755 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 1756 return -EINVAL; 1757 1758 le = kzalloc(sizeof(*le), GFP_KERNEL); 1759 if (!le) 1760 return -ENOMEM; 1761 le->gdev = gdev; 1762 get_device(&gdev->dev); 1763 1764 if (eventreq.consumer_label[0] != '\0') { 1765 /* label is only initialized if consumer_label is set */ 1766 le->label = kstrndup(eventreq.consumer_label, 1767 sizeof(eventreq.consumer_label) - 1, 1768 GFP_KERNEL); 1769 if (!le->label) { 1770 ret = -ENOMEM; 1771 goto out_free_le; 1772 } 1773 } 1774 1775 ret = gpiod_request(desc, le->label); 1776 if (ret) 1777 goto out_free_le; 1778 le->desc = desc; 1779 le->eflags = eflags; 1780 1781 linehandle_flags_to_desc_flags(lflags, &desc->flags); 1782 1783 ret = gpiod_direction_input(desc); 1784 if (ret) 1785 goto out_free_le; 1786 1787 blocking_notifier_call_chain(&desc->gdev->notifier, 1788 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 1789 1790 irq = gpiod_to_irq(desc); 1791 if (irq <= 0) { 1792 ret = -ENODEV; 1793 goto out_free_le; 1794 } 1795 1796 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE) 1797 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 1798 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 1799 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE) 1800 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 1801 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 1802 irqflags |= IRQF_ONESHOT; 1803 1804 INIT_KFIFO(le->events); 1805 init_waitqueue_head(&le->wait); 1806 1807 /* Request a thread to read the events */ 1808 ret = request_threaded_irq(irq, 1809 lineevent_irq_handler, 1810 lineevent_irq_thread, 1811 irqflags, 1812 le->label, 1813 le); 1814 if (ret) 1815 goto out_free_le; 1816 1817 le->irq = irq; 1818 1819 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 1820 if (fd < 0) { 1821 ret = fd; 1822 goto out_free_le; 1823 } 1824 1825 file = anon_inode_getfile("gpio-event", 1826 &lineevent_fileops, 1827 le, 1828 O_RDONLY | O_CLOEXEC); 1829 if (IS_ERR(file)) { 1830 ret = PTR_ERR(file); 1831 goto out_put_unused_fd; 1832 } 1833 1834 eventreq.fd = fd; 1835 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) { 1836 /* 1837 * fput() will trigger the release() callback, so do not go onto 1838 * the regular error cleanup path here. 1839 */ 1840 fput(file); 1841 put_unused_fd(fd); 1842 return -EFAULT; 1843 } 1844 1845 fd_install(fd, file); 1846 1847 return 0; 1848 1849out_put_unused_fd: 1850 put_unused_fd(fd); 1851out_free_le: 1852 lineevent_free(le); 1853 return ret; 1854} 1855 1856static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2, 1857 struct gpioline_info *info_v1) 1858{ 1859 u64 flagsv2 = info_v2->flags; 1860 1861 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name)); 1862 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer)); 1863 info_v1->line_offset = info_v2->offset; 1864 info_v1->flags = 0; 1865 1866 if (flagsv2 & GPIO_V2_LINE_FLAG_USED) 1867 info_v1->flags |= GPIOLINE_FLAG_KERNEL; 1868 1869 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT) 1870 info_v1->flags |= GPIOLINE_FLAG_IS_OUT; 1871 1872 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 1873 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW; 1874 1875 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN) 1876 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN; 1877 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE) 1878 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE; 1879 1880 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP) 1881 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP; 1882 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) 1883 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN; 1884 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED) 1885 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE; 1886} 1887 1888static void gpio_v2_line_info_changed_to_v1( 1889 struct gpio_v2_line_info_changed *lic_v2, 1890 struct gpioline_info_changed *lic_v1) 1891{ 1892 memset(lic_v1, 0, sizeof(*lic_v1)); 1893 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info); 1894 lic_v1->timestamp = lic_v2->timestamp_ns; 1895 lic_v1->event_type = lic_v2->event_type; 1896} 1897 1898#endif /* CONFIG_GPIO_CDEV_V1 */ 1899 1900static void gpio_desc_to_lineinfo(struct gpio_desc *desc, 1901 struct gpio_v2_line_info *info) 1902{ 1903 struct gpio_chip *gc = desc->gdev->chip; 1904 bool ok_for_pinctrl; 1905 unsigned long flags; 1906 u32 debounce_period_us; 1907 unsigned int num_attrs = 0; 1908 1909 memset(info, 0, sizeof(*info)); 1910 info->offset = gpio_chip_hwgpio(desc); 1911 1912 /* 1913 * This function takes a mutex so we must check this before taking 1914 * the spinlock. 1915 * 1916 * FIXME: find a non-racy way to retrieve this information. Maybe a 1917 * lock common to both frameworks? 1918 */ 1919 ok_for_pinctrl = 1920 pinctrl_gpio_can_use_line(gc->base + info->offset); 1921 1922 spin_lock_irqsave(&gpio_lock, flags); 1923 1924 if (desc->name) 1925 strscpy(info->name, desc->name, sizeof(info->name)); 1926 1927 if (desc->label) 1928 strscpy(info->consumer, desc->label, sizeof(info->consumer)); 1929 1930 /* 1931 * Userspace only need to know that the kernel is using this GPIO so 1932 * it can't use it. 1933 */ 1934 info->flags = 0; 1935 if (test_bit(FLAG_REQUESTED, &desc->flags) || 1936 test_bit(FLAG_IS_HOGGED, &desc->flags) || 1937 test_bit(FLAG_USED_AS_IRQ, &desc->flags) || 1938 test_bit(FLAG_EXPORT, &desc->flags) || 1939 test_bit(FLAG_SYSFS, &desc->flags) || 1940 !ok_for_pinctrl) 1941 info->flags |= GPIO_V2_LINE_FLAG_USED; 1942 1943 if (test_bit(FLAG_IS_OUT, &desc->flags)) 1944 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT; 1945 else 1946 info->flags |= GPIO_V2_LINE_FLAG_INPUT; 1947 1948 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) 1949 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW; 1950 1951 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) 1952 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN; 1953 if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) 1954 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE; 1955 1956 if (test_bit(FLAG_BIAS_DISABLE, &desc->flags)) 1957 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED; 1958 if (test_bit(FLAG_PULL_DOWN, &desc->flags)) 1959 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN; 1960 if (test_bit(FLAG_PULL_UP, &desc->flags)) 1961 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP; 1962 1963 if (test_bit(FLAG_EDGE_RISING, &desc->flags)) 1964 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING; 1965 if (test_bit(FLAG_EDGE_FALLING, &desc->flags)) 1966 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING; 1967 1968 debounce_period_us = READ_ONCE(desc->debounce_period_us); 1969 if (debounce_period_us) { 1970 info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; 1971 info->attrs[num_attrs].debounce_period_us = debounce_period_us; 1972 num_attrs++; 1973 } 1974 info->num_attrs = num_attrs; 1975 1976 spin_unlock_irqrestore(&gpio_lock, flags); 1977} 1978 1979struct gpio_chardev_data { 1980 struct gpio_device *gdev; 1981 wait_queue_head_t wait; 1982 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32); 1983 struct notifier_block lineinfo_changed_nb; 1984 unsigned long *watched_lines; 1985#ifdef CONFIG_GPIO_CDEV_V1 1986 atomic_t watch_abi_version; 1987#endif 1988}; 1989 1990static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip) 1991{ 1992 struct gpio_device *gdev = cdev->gdev; 1993 struct gpiochip_info chipinfo; 1994 1995 memset(&chipinfo, 0, sizeof(chipinfo)); 1996 1997 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name)); 1998 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label)); 1999 chipinfo.lines = gdev->ngpio; 2000 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo))) 2001 return -EFAULT; 2002 return 0; 2003} 2004 2005#ifdef CONFIG_GPIO_CDEV_V1 2006/* 2007 * returns 0 if the versions match, else the previously selected ABI version 2008 */ 2009static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata, 2010 unsigned int version) 2011{ 2012 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version); 2013 2014 if (abiv == version) 2015 return 0; 2016 2017 return abiv; 2018} 2019 2020static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip, 2021 bool watch) 2022{ 2023 struct gpio_desc *desc; 2024 struct gpioline_info lineinfo; 2025 struct gpio_v2_line_info lineinfo_v2; 2026 2027 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2028 return -EFAULT; 2029 2030 /* this doubles as a range check on line_offset */ 2031 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset); 2032 if (IS_ERR(desc)) 2033 return PTR_ERR(desc); 2034 2035 if (watch) { 2036 if (lineinfo_ensure_abi_version(cdev, 1)) 2037 return -EPERM; 2038 2039 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines)) 2040 return -EBUSY; 2041 } 2042 2043 gpio_desc_to_lineinfo(desc, &lineinfo_v2); 2044 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); 2045 2046 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2047 if (watch) 2048 clear_bit(lineinfo.line_offset, cdev->watched_lines); 2049 return -EFAULT; 2050 } 2051 2052 return 0; 2053} 2054#endif 2055 2056static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, 2057 bool watch) 2058{ 2059 struct gpio_desc *desc; 2060 struct gpio_v2_line_info lineinfo; 2061 2062 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2063 return -EFAULT; 2064 2065 if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding))) 2066 return -EINVAL; 2067 2068 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset); 2069 if (IS_ERR(desc)) 2070 return PTR_ERR(desc); 2071 2072 if (watch) { 2073#ifdef CONFIG_GPIO_CDEV_V1 2074 if (lineinfo_ensure_abi_version(cdev, 2)) 2075 return -EPERM; 2076#endif 2077 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines)) 2078 return -EBUSY; 2079 } 2080 gpio_desc_to_lineinfo(desc, &lineinfo); 2081 2082 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2083 if (watch) 2084 clear_bit(lineinfo.offset, cdev->watched_lines); 2085 return -EFAULT; 2086 } 2087 2088 return 0; 2089} 2090 2091static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip) 2092{ 2093 __u32 offset; 2094 2095 if (copy_from_user(&offset, ip, sizeof(offset))) 2096 return -EFAULT; 2097 2098 if (offset >= cdev->gdev->ngpio) 2099 return -EINVAL; 2100 2101 if (!test_and_clear_bit(offset, cdev->watched_lines)) 2102 return -EBUSY; 2103 2104 return 0; 2105} 2106 2107/* 2108 * gpio_ioctl() - ioctl handler for the GPIO chardev 2109 */ 2110static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 2111{ 2112 struct gpio_chardev_data *cdev = file->private_data; 2113 struct gpio_device *gdev = cdev->gdev; 2114 void __user *ip = (void __user *)arg; 2115 2116 /* We fail any subsequent ioctl():s when the chip is gone */ 2117 if (!gdev->chip) 2118 return -ENODEV; 2119 2120 /* Fill in the struct and pass to userspace */ 2121 switch (cmd) { 2122 case GPIO_GET_CHIPINFO_IOCTL: 2123 return chipinfo_get(cdev, ip); 2124#ifdef CONFIG_GPIO_CDEV_V1 2125 case GPIO_GET_LINEHANDLE_IOCTL: 2126 return linehandle_create(gdev, ip); 2127 case GPIO_GET_LINEEVENT_IOCTL: 2128 return lineevent_create(gdev, ip); 2129 case GPIO_GET_LINEINFO_IOCTL: 2130 return lineinfo_get_v1(cdev, ip, false); 2131 case GPIO_GET_LINEINFO_WATCH_IOCTL: 2132 return lineinfo_get_v1(cdev, ip, true); 2133#endif /* CONFIG_GPIO_CDEV_V1 */ 2134 case GPIO_V2_GET_LINEINFO_IOCTL: 2135 return lineinfo_get(cdev, ip, false); 2136 case GPIO_V2_GET_LINEINFO_WATCH_IOCTL: 2137 return lineinfo_get(cdev, ip, true); 2138 case GPIO_V2_GET_LINE_IOCTL: 2139 return linereq_create(gdev, ip); 2140 case GPIO_GET_LINEINFO_UNWATCH_IOCTL: 2141 return lineinfo_unwatch(cdev, ip); 2142 default: 2143 return -EINVAL; 2144 } 2145} 2146 2147#ifdef CONFIG_COMPAT 2148static long gpio_ioctl_compat(struct file *file, unsigned int cmd, 2149 unsigned long arg) 2150{ 2151 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 2152} 2153#endif 2154 2155static struct gpio_chardev_data * 2156to_gpio_chardev_data(struct notifier_block *nb) 2157{ 2158 return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb); 2159} 2160 2161static int lineinfo_changed_notify(struct notifier_block *nb, 2162 unsigned long action, void *data) 2163{ 2164 struct gpio_chardev_data *cdev = to_gpio_chardev_data(nb); 2165 struct gpio_v2_line_info_changed chg; 2166 struct gpio_desc *desc = data; 2167 int ret; 2168 2169 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines)) 2170 return NOTIFY_DONE; 2171 2172 memset(&chg, 0, sizeof(chg)); 2173 chg.event_type = action; 2174 chg.timestamp_ns = ktime_get_ns(); 2175 gpio_desc_to_lineinfo(desc, &chg.info); 2176 2177 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock); 2178 if (ret) 2179 wake_up_poll(&cdev->wait, EPOLLIN); 2180 else 2181 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n"); 2182 2183 return NOTIFY_OK; 2184} 2185 2186static __poll_t lineinfo_watch_poll(struct file *file, 2187 struct poll_table_struct *pollt) 2188{ 2189 struct gpio_chardev_data *cdev = file->private_data; 2190 __poll_t events = 0; 2191 2192 if (!cdev->gdev->chip) 2193 return EPOLLHUP | EPOLLERR; 2194 2195 poll_wait(file, &cdev->wait, pollt); 2196 2197 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events, 2198 &cdev->wait.lock)) 2199 events = EPOLLIN | EPOLLRDNORM; 2200 2201 return events; 2202} 2203 2204static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, 2205 size_t count, loff_t *off) 2206{ 2207 struct gpio_chardev_data *cdev = file->private_data; 2208 struct gpio_v2_line_info_changed event; 2209 ssize_t bytes_read = 0; 2210 int ret; 2211 size_t event_size; 2212 2213 if (!cdev->gdev->chip) 2214 return -ENODEV; 2215 2216#ifndef CONFIG_GPIO_CDEV_V1 2217 event_size = sizeof(struct gpio_v2_line_info_changed); 2218 if (count < event_size) 2219 return -EINVAL; 2220#endif 2221 2222 do { 2223 spin_lock(&cdev->wait.lock); 2224 if (kfifo_is_empty(&cdev->events)) { 2225 if (bytes_read) { 2226 spin_unlock(&cdev->wait.lock); 2227 return bytes_read; 2228 } 2229 2230 if (file->f_flags & O_NONBLOCK) { 2231 spin_unlock(&cdev->wait.lock); 2232 return -EAGAIN; 2233 } 2234 2235 ret = wait_event_interruptible_locked(cdev->wait, 2236 !kfifo_is_empty(&cdev->events)); 2237 if (ret) { 2238 spin_unlock(&cdev->wait.lock); 2239 return ret; 2240 } 2241 } 2242#ifdef CONFIG_GPIO_CDEV_V1 2243 /* must be after kfifo check so watch_abi_version is set */ 2244 if (atomic_read(&cdev->watch_abi_version) == 2) 2245 event_size = sizeof(struct gpio_v2_line_info_changed); 2246 else 2247 event_size = sizeof(struct gpioline_info_changed); 2248 if (count < event_size) { 2249 spin_unlock(&cdev->wait.lock); 2250 return -EINVAL; 2251 } 2252#endif 2253 ret = kfifo_out(&cdev->events, &event, 1); 2254 spin_unlock(&cdev->wait.lock); 2255 if (ret != 1) { 2256 ret = -EIO; 2257 break; 2258 /* We should never get here. See lineevent_read(). */ 2259 } 2260 2261#ifdef CONFIG_GPIO_CDEV_V1 2262 if (event_size == sizeof(struct gpio_v2_line_info_changed)) { 2263 if (copy_to_user(buf + bytes_read, &event, event_size)) 2264 return -EFAULT; 2265 } else { 2266 struct gpioline_info_changed event_v1; 2267 2268 gpio_v2_line_info_changed_to_v1(&event, &event_v1); 2269 if (copy_to_user(buf + bytes_read, &event_v1, 2270 event_size)) 2271 return -EFAULT; 2272 } 2273#else 2274 if (copy_to_user(buf + bytes_read, &event, event_size)) 2275 return -EFAULT; 2276#endif 2277 bytes_read += event_size; 2278 } while (count >= bytes_read + sizeof(event)); 2279 2280 return bytes_read; 2281} 2282 2283/** 2284 * gpio_chrdev_open() - open the chardev for ioctl operations 2285 * @inode: inode for this chardev 2286 * @file: file struct for storing private data 2287 * Returns 0 on success 2288 */ 2289static int gpio_chrdev_open(struct inode *inode, struct file *file) 2290{ 2291 struct gpio_device *gdev = container_of(inode->i_cdev, 2292 struct gpio_device, chrdev); 2293 struct gpio_chardev_data *cdev; 2294 int ret = -ENOMEM; 2295 2296 /* Fail on open if the backing gpiochip is gone */ 2297 if (!gdev->chip) 2298 return -ENODEV; 2299 2300 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL); 2301 if (!cdev) 2302 return -ENOMEM; 2303 2304 cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL); 2305 if (!cdev->watched_lines) 2306 goto out_free_cdev; 2307 2308 init_waitqueue_head(&cdev->wait); 2309 INIT_KFIFO(cdev->events); 2310 cdev->gdev = gdev; 2311 2312 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify; 2313 ret = blocking_notifier_chain_register(&gdev->notifier, 2314 &cdev->lineinfo_changed_nb); 2315 if (ret) 2316 goto out_free_bitmap; 2317 2318 get_device(&gdev->dev); 2319 file->private_data = cdev; 2320 2321 ret = nonseekable_open(inode, file); 2322 if (ret) 2323 goto out_unregister_notifier; 2324 2325 return ret; 2326 2327out_unregister_notifier: 2328 blocking_notifier_chain_unregister(&gdev->notifier, 2329 &cdev->lineinfo_changed_nb); 2330out_free_bitmap: 2331 bitmap_free(cdev->watched_lines); 2332out_free_cdev: 2333 kfree(cdev); 2334 return ret; 2335} 2336 2337/** 2338 * gpio_chrdev_release() - close chardev after ioctl operations 2339 * @inode: inode for this chardev 2340 * @file: file struct for storing private data 2341 * Returns 0 on success 2342 */ 2343static int gpio_chrdev_release(struct inode *inode, struct file *file) 2344{ 2345 struct gpio_chardev_data *cdev = file->private_data; 2346 struct gpio_device *gdev = cdev->gdev; 2347 2348 blocking_notifier_chain_unregister(&gdev->notifier, 2349 &cdev->lineinfo_changed_nb); 2350 bitmap_free(cdev->watched_lines); 2351 put_device(&gdev->dev); 2352 kfree(cdev); 2353 2354 return 0; 2355} 2356 2357static const struct file_operations gpio_fileops = { 2358 .release = gpio_chrdev_release, 2359 .open = gpio_chrdev_open, 2360 .poll = lineinfo_watch_poll, 2361 .read = lineinfo_watch_read, 2362 .owner = THIS_MODULE, 2363 .llseek = no_llseek, 2364 .unlocked_ioctl = gpio_ioctl, 2365#ifdef CONFIG_COMPAT 2366 .compat_ioctl = gpio_ioctl_compat, 2367#endif 2368}; 2369 2370int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt) 2371{ 2372 int ret; 2373 2374 cdev_init(&gdev->chrdev, &gpio_fileops); 2375 gdev->chrdev.owner = THIS_MODULE; 2376 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id); 2377 2378 ret = cdev_device_add(&gdev->chrdev, &gdev->dev); 2379 if (ret) 2380 return ret; 2381 2382 chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n", 2383 MAJOR(devt), gdev->id); 2384 2385 return 0; 2386} 2387 2388void gpiolib_cdev_unregister(struct gpio_device *gdev) 2389{ 2390 cdev_device_del(&gdev->chrdev, &gdev->dev); 2391} 2392