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/cleanup.h> 9 #include <linux/compat.h> 10 #include <linux/compiler.h> 11 #include <linux/device.h> 12 #include <linux/err.h> 13 #include <linux/file.h> 14 #include <linux/gpio.h> 15 #include <linux/gpio/driver.h> 16 #include <linux/hte.h> 17 #include <linux/interrupt.h> 18 #include <linux/irqreturn.h> 19 #include <linux/kfifo.h> 20 #include <linux/module.h> 21 #include <linux/mutex.h> 22 #include <linux/overflow.h> 23 #include <linux/pinctrl/consumer.h> 24 #include <linux/poll.h> 25 #include <linux/seq_file.h> 26 #include <linux/spinlock.h> 27 #include <linux/string.h> 28 #include <linux/timekeeping.h> 29 #include <linux/uaccess.h> 30 #include <linux/workqueue.h> 31 32 #include <uapi/linux/gpio.h> 33 34 #include "gpiolib.h" 35 #include "gpiolib-cdev.h" 36 37 /* 38 * Array sizes must ensure 64-bit alignment and not create holes in the 39 * struct packing. 40 */ 41 static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2)); 42 static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8)); 43 44 /* 45 * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility 46 */ 47 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8)); 48 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8)); 49 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8)); 50 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8)); 51 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8)); 52 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8)); 53 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8)); 54 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8)); 55 56 /* Character device interface to GPIO. 57 * 58 * The GPIO character device, /dev/gpiochipN, provides userspace an 59 * interface to gpiolib GPIOs via ioctl()s. 60 */ 61 62 /* 63 * GPIO line handle management 64 */ 65 66 #ifdef CONFIG_GPIO_CDEV_V1 67 /** 68 * struct linehandle_state - contains the state of a userspace handle 69 * @gdev: the GPIO device the handle pertains to 70 * @label: consumer label used to tag descriptors 71 * @descs: the GPIO descriptors held by this handle 72 * @num_descs: the number of descriptors held in the descs array 73 */ 74 struct linehandle_state { 75 struct gpio_device *gdev; 76 const char *label; 77 struct gpio_desc *descs[GPIOHANDLES_MAX]; 78 u32 num_descs; 79 }; 80 81 #define GPIOHANDLE_REQUEST_VALID_FLAGS \ 82 (GPIOHANDLE_REQUEST_INPUT | \ 83 GPIOHANDLE_REQUEST_OUTPUT | \ 84 GPIOHANDLE_REQUEST_ACTIVE_LOW | \ 85 GPIOHANDLE_REQUEST_BIAS_PULL_UP | \ 86 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \ 87 GPIOHANDLE_REQUEST_BIAS_DISABLE | \ 88 GPIOHANDLE_REQUEST_OPEN_DRAIN | \ 89 GPIOHANDLE_REQUEST_OPEN_SOURCE) 90 91 #define GPIOHANDLE_REQUEST_DIRECTION_FLAGS \ 92 (GPIOHANDLE_REQUEST_INPUT | \ 93 GPIOHANDLE_REQUEST_OUTPUT) 94 95 static int linehandle_validate_flags(u32 flags) 96 { 97 /* Return an error if an unknown flag is set */ 98 if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) 99 return -EINVAL; 100 101 /* 102 * Do not allow both INPUT & OUTPUT flags to be set as they are 103 * contradictory. 104 */ 105 if ((flags & GPIOHANDLE_REQUEST_INPUT) && 106 (flags & GPIOHANDLE_REQUEST_OUTPUT)) 107 return -EINVAL; 108 109 /* 110 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If 111 * the hardware actually supports enabling both at the same time the 112 * electrical result would be disastrous. 113 */ 114 if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) && 115 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 116 return -EINVAL; 117 118 /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */ 119 if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) && 120 ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 121 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))) 122 return -EINVAL; 123 124 /* Bias flags only allowed for input or output mode. */ 125 if (!((flags & GPIOHANDLE_REQUEST_INPUT) || 126 (flags & GPIOHANDLE_REQUEST_OUTPUT)) && 127 ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) || 128 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) || 129 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN))) 130 return -EINVAL; 131 132 /* Only one bias flag can be set. */ 133 if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 134 (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 135 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 136 ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 137 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 138 return -EINVAL; 139 140 return 0; 141 } 142 143 static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp) 144 { 145 unsigned long flags = READ_ONCE(*flagsp); 146 147 assign_bit(FLAG_ACTIVE_LOW, &flags, 148 lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW); 149 assign_bit(FLAG_OPEN_DRAIN, &flags, 150 lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN); 151 assign_bit(FLAG_OPEN_SOURCE, &flags, 152 lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE); 153 assign_bit(FLAG_PULL_UP, &flags, 154 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP); 155 assign_bit(FLAG_PULL_DOWN, &flags, 156 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN); 157 assign_bit(FLAG_BIAS_DISABLE, &flags, 158 lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE); 159 160 WRITE_ONCE(*flagsp, flags); 161 } 162 163 static long linehandle_set_config(struct linehandle_state *lh, 164 void __user *ip) 165 { 166 struct gpiohandle_config gcnf; 167 struct gpio_desc *desc; 168 int i, ret; 169 u32 lflags; 170 171 if (copy_from_user(&gcnf, ip, sizeof(gcnf))) 172 return -EFAULT; 173 174 lflags = gcnf.flags; 175 ret = linehandle_validate_flags(lflags); 176 if (ret) 177 return ret; 178 179 /* Lines must be reconfigured explicitly as input or output. */ 180 if (!(lflags & GPIOHANDLE_REQUEST_DIRECTION_FLAGS)) 181 return -EINVAL; 182 183 for (i = 0; i < lh->num_descs; i++) { 184 desc = lh->descs[i]; 185 linehandle_flags_to_desc_flags(lflags, &desc->flags); 186 187 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { 188 int val = !!gcnf.default_values[i]; 189 190 ret = gpiod_direction_output_nonotify(desc, val); 191 if (ret) 192 return ret; 193 } else { 194 ret = gpiod_direction_input_nonotify(desc); 195 if (ret) 196 return ret; 197 } 198 199 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG); 200 } 201 return 0; 202 } 203 204 static long linehandle_ioctl(struct file *file, unsigned int cmd, 205 unsigned long arg) 206 { 207 struct linehandle_state *lh = file->private_data; 208 void __user *ip = (void __user *)arg; 209 struct gpiohandle_data ghd; 210 DECLARE_BITMAP(vals, GPIOHANDLES_MAX); 211 unsigned int i; 212 int ret; 213 214 guard(srcu)(&lh->gdev->srcu); 215 216 if (!rcu_access_pointer(lh->gdev->chip)) 217 return -ENODEV; 218 219 switch (cmd) { 220 case GPIOHANDLE_GET_LINE_VALUES_IOCTL: 221 /* NOTE: It's okay to read values of output lines */ 222 ret = gpiod_get_array_value_complex(false, true, 223 lh->num_descs, lh->descs, 224 NULL, vals); 225 if (ret) 226 return ret; 227 228 memset(&ghd, 0, sizeof(ghd)); 229 for (i = 0; i < lh->num_descs; i++) 230 ghd.values[i] = test_bit(i, vals); 231 232 if (copy_to_user(ip, &ghd, sizeof(ghd))) 233 return -EFAULT; 234 235 return 0; 236 case GPIOHANDLE_SET_LINE_VALUES_IOCTL: 237 /* 238 * All line descriptors were created at once with the same 239 * flags so just check if the first one is really output. 240 */ 241 if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags)) 242 return -EPERM; 243 244 if (copy_from_user(&ghd, ip, sizeof(ghd))) 245 return -EFAULT; 246 247 /* Clamp all values to [0,1] */ 248 for (i = 0; i < lh->num_descs; i++) 249 __assign_bit(i, vals, ghd.values[i]); 250 251 /* Reuse the array setting function */ 252 return gpiod_set_array_value_complex(false, 253 true, 254 lh->num_descs, 255 lh->descs, 256 NULL, 257 vals); 258 case GPIOHANDLE_SET_CONFIG_IOCTL: 259 return linehandle_set_config(lh, ip); 260 default: 261 return -EINVAL; 262 } 263 } 264 265 #ifdef CONFIG_COMPAT 266 static long linehandle_ioctl_compat(struct file *file, unsigned int cmd, 267 unsigned long arg) 268 { 269 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 270 } 271 #endif 272 273 static void linehandle_free(struct linehandle_state *lh) 274 { 275 int i; 276 277 for (i = 0; i < lh->num_descs; i++) 278 if (lh->descs[i]) 279 gpiod_free(lh->descs[i]); 280 kfree(lh->label); 281 gpio_device_put(lh->gdev); 282 kfree(lh); 283 } 284 285 static int linehandle_release(struct inode *inode, struct file *file) 286 { 287 linehandle_free(file->private_data); 288 return 0; 289 } 290 291 static const struct file_operations linehandle_fileops = { 292 .release = linehandle_release, 293 .owner = THIS_MODULE, 294 .llseek = noop_llseek, 295 .unlocked_ioctl = linehandle_ioctl, 296 #ifdef CONFIG_COMPAT 297 .compat_ioctl = linehandle_ioctl_compat, 298 #endif 299 }; 300 301 static int linehandle_create(struct gpio_device *gdev, void __user *ip) 302 { 303 struct gpiohandle_request handlereq; 304 struct linehandle_state *lh; 305 struct file *file; 306 int fd, i, ret; 307 u32 lflags; 308 309 if (copy_from_user(&handlereq, ip, sizeof(handlereq))) 310 return -EFAULT; 311 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX)) 312 return -EINVAL; 313 314 lflags = handlereq.flags; 315 316 ret = linehandle_validate_flags(lflags); 317 if (ret) 318 return ret; 319 320 lh = kzalloc(sizeof(*lh), GFP_KERNEL); 321 if (!lh) 322 return -ENOMEM; 323 lh->gdev = gpio_device_get(gdev); 324 325 if (handlereq.consumer_label[0] != '\0') { 326 /* label is only initialized if consumer_label is set */ 327 lh->label = kstrndup(handlereq.consumer_label, 328 sizeof(handlereq.consumer_label) - 1, 329 GFP_KERNEL); 330 if (!lh->label) { 331 ret = -ENOMEM; 332 goto out_free_lh; 333 } 334 } 335 336 lh->num_descs = handlereq.lines; 337 338 /* Request each GPIO */ 339 for (i = 0; i < handlereq.lines; i++) { 340 u32 offset = handlereq.lineoffsets[i]; 341 struct gpio_desc *desc = gpio_device_get_desc(gdev, offset); 342 343 if (IS_ERR(desc)) { 344 ret = PTR_ERR(desc); 345 goto out_free_lh; 346 } 347 348 ret = gpiod_request_user(desc, lh->label); 349 if (ret) 350 goto out_free_lh; 351 lh->descs[i] = desc; 352 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags); 353 354 ret = gpiod_set_transitory(desc, false); 355 if (ret < 0) 356 goto out_free_lh; 357 358 /* 359 * Lines have to be requested explicitly for input 360 * or output, else the line will be treated "as is". 361 */ 362 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { 363 int val = !!handlereq.default_values[i]; 364 365 ret = gpiod_direction_output_nonotify(desc, val); 366 if (ret) 367 goto out_free_lh; 368 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { 369 ret = gpiod_direction_input_nonotify(desc); 370 if (ret) 371 goto out_free_lh; 372 } 373 374 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED); 375 376 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 377 offset); 378 } 379 380 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 381 if (fd < 0) { 382 ret = fd; 383 goto out_free_lh; 384 } 385 386 file = anon_inode_getfile("gpio-linehandle", 387 &linehandle_fileops, 388 lh, 389 O_RDONLY | O_CLOEXEC); 390 if (IS_ERR(file)) { 391 ret = PTR_ERR(file); 392 goto out_put_unused_fd; 393 } 394 395 handlereq.fd = fd; 396 if (copy_to_user(ip, &handlereq, sizeof(handlereq))) { 397 /* 398 * fput() will trigger the release() callback, so do not go onto 399 * the regular error cleanup path here. 400 */ 401 fput(file); 402 put_unused_fd(fd); 403 return -EFAULT; 404 } 405 406 fd_install(fd, file); 407 408 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 409 lh->num_descs); 410 411 return 0; 412 413 out_put_unused_fd: 414 put_unused_fd(fd); 415 out_free_lh: 416 linehandle_free(lh); 417 return ret; 418 } 419 #endif /* CONFIG_GPIO_CDEV_V1 */ 420 421 /** 422 * struct line - contains the state of a requested line 423 * @desc: the GPIO descriptor for this line. 424 * @req: the corresponding line request 425 * @irq: the interrupt triggered in response to events on this GPIO 426 * @edflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or 427 * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied 428 * @timestamp_ns: cache for the timestamp storing it between hardirq and 429 * IRQ thread, used to bring the timestamp close to the actual event 430 * @req_seqno: the seqno for the current edge event in the sequence of 431 * events for the corresponding line request. This is drawn from the @req. 432 * @line_seqno: the seqno for the current edge event in the sequence of 433 * events for this line. 434 * @work: the worker that implements software debouncing 435 * @sw_debounced: flag indicating if the software debouncer is active 436 * @level: the current debounced physical level of the line 437 * @hdesc: the Hardware Timestamp Engine (HTE) descriptor 438 * @raw_level: the line level at the time of event 439 * @total_discard_seq: the running counter of the discarded events 440 * @last_seqno: the last sequence number before debounce period expires 441 */ 442 struct line { 443 struct gpio_desc *desc; 444 /* 445 * -- edge detector specific fields -- 446 */ 447 struct linereq *req; 448 unsigned int irq; 449 /* 450 * The flags for the active edge detector configuration. 451 * 452 * edflags is set by linereq_create(), linereq_free(), and 453 * linereq_set_config(), which are themselves mutually 454 * exclusive, and is accessed by edge_irq_thread(), 455 * process_hw_ts_thread() and debounce_work_func(), 456 * which can all live with a slightly stale value. 457 */ 458 u64 edflags; 459 /* 460 * timestamp_ns and req_seqno are accessed only by 461 * edge_irq_handler() and edge_irq_thread(), which are themselves 462 * mutually exclusive, so no additional protection is necessary. 463 */ 464 u64 timestamp_ns; 465 u32 req_seqno; 466 /* 467 * line_seqno is accessed by either edge_irq_thread() or 468 * debounce_work_func(), which are themselves mutually exclusive, 469 * so no additional protection is necessary. 470 */ 471 u32 line_seqno; 472 /* 473 * -- debouncer specific fields -- 474 */ 475 struct delayed_work work; 476 /* 477 * sw_debounce is accessed by linereq_set_config(), which is the 478 * only setter, and linereq_get_values(), which can live with a 479 * slightly stale value. 480 */ 481 unsigned int sw_debounced; 482 /* 483 * level is accessed by debounce_work_func(), which is the only 484 * setter, and linereq_get_values() which can live with a slightly 485 * stale value. 486 */ 487 unsigned int level; 488 #ifdef CONFIG_HTE 489 struct hte_ts_desc hdesc; 490 /* 491 * HTE provider sets line level at the time of event. The valid 492 * value is 0 or 1 and negative value for an error. 493 */ 494 int raw_level; 495 /* 496 * when sw_debounce is set on HTE enabled line, this is running 497 * counter of the discarded events. 498 */ 499 u32 total_discard_seq; 500 /* 501 * when sw_debounce is set on HTE enabled line, this variable records 502 * last sequence number before debounce period expires. 503 */ 504 u32 last_seqno; 505 #endif /* CONFIG_HTE */ 506 }; 507 508 /** 509 * struct linereq - contains the state of a userspace line request 510 * @gdev: the GPIO device the line request pertains to 511 * @label: consumer label used to tag GPIO descriptors 512 * @num_lines: the number of lines in the lines array 513 * @wait: wait queue that handles blocking reads of events 514 * @device_unregistered_nb: notifier block for receiving gdev unregister events 515 * @event_buffer_size: the number of elements allocated in @events 516 * @events: KFIFO for the GPIO events 517 * @seqno: the sequence number for edge events generated on all lines in 518 * this line request. Note that this is not used when @num_lines is 1, as 519 * the line_seqno is then the same and is cheaper to calculate. 520 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency 521 * of configuration, particularly multi-step accesses to desc flags. 522 * @lines: the lines held by this line request, with @num_lines elements. 523 */ 524 struct linereq { 525 struct gpio_device *gdev; 526 const char *label; 527 u32 num_lines; 528 wait_queue_head_t wait; 529 struct notifier_block device_unregistered_nb; 530 u32 event_buffer_size; 531 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event); 532 atomic_t seqno; 533 struct mutex config_mutex; 534 struct line lines[] __counted_by(num_lines); 535 }; 536 537 #define GPIO_V2_LINE_BIAS_FLAGS \ 538 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \ 539 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \ 540 GPIO_V2_LINE_FLAG_BIAS_DISABLED) 541 542 #define GPIO_V2_LINE_DIRECTION_FLAGS \ 543 (GPIO_V2_LINE_FLAG_INPUT | \ 544 GPIO_V2_LINE_FLAG_OUTPUT) 545 546 #define GPIO_V2_LINE_DRIVE_FLAGS \ 547 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \ 548 GPIO_V2_LINE_FLAG_OPEN_SOURCE) 549 550 #define GPIO_V2_LINE_EDGE_FLAGS \ 551 (GPIO_V2_LINE_FLAG_EDGE_RISING | \ 552 GPIO_V2_LINE_FLAG_EDGE_FALLING) 553 554 #define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS 555 556 #define GPIO_V2_LINE_VALID_FLAGS \ 557 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ 558 GPIO_V2_LINE_DIRECTION_FLAGS | \ 559 GPIO_V2_LINE_DRIVE_FLAGS | \ 560 GPIO_V2_LINE_EDGE_FLAGS | \ 561 GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \ 562 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \ 563 GPIO_V2_LINE_BIAS_FLAGS) 564 565 /* subset of flags relevant for edge detector configuration */ 566 #define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \ 567 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ 568 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \ 569 GPIO_V2_LINE_EDGE_FLAGS) 570 571 static int linereq_unregistered_notify(struct notifier_block *nb, 572 unsigned long action, void *data) 573 { 574 struct linereq *lr = container_of(nb, struct linereq, 575 device_unregistered_nb); 576 577 wake_up_poll(&lr->wait, EPOLLIN | EPOLLERR); 578 579 return NOTIFY_OK; 580 } 581 582 static void linereq_put_event(struct linereq *lr, 583 struct gpio_v2_line_event *le) 584 { 585 bool overflow = false; 586 587 scoped_guard(spinlock, &lr->wait.lock) { 588 if (kfifo_is_full(&lr->events)) { 589 overflow = true; 590 kfifo_skip(&lr->events); 591 } 592 kfifo_in(&lr->events, le, 1); 593 } 594 if (!overflow) 595 wake_up_poll(&lr->wait, EPOLLIN); 596 else 597 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 598 } 599 600 static u64 line_event_timestamp(struct line *line) 601 { 602 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags)) 603 return ktime_get_real_ns(); 604 else if (IS_ENABLED(CONFIG_HTE) && 605 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags)) 606 return line->timestamp_ns; 607 608 return ktime_get_ns(); 609 } 610 611 static u32 line_event_id(int level) 612 { 613 return level ? GPIO_V2_LINE_EVENT_RISING_EDGE : 614 GPIO_V2_LINE_EVENT_FALLING_EDGE; 615 } 616 617 static inline char *make_irq_label(const char *orig) 618 { 619 char *new; 620 621 if (!orig) 622 return NULL; 623 624 new = kstrdup_and_replace(orig, '/', ':', GFP_KERNEL); 625 if (!new) 626 return ERR_PTR(-ENOMEM); 627 628 return new; 629 } 630 631 static inline void free_irq_label(const char *label) 632 { 633 kfree(label); 634 } 635 636 #ifdef CONFIG_HTE 637 638 static enum hte_return process_hw_ts_thread(void *p) 639 { 640 struct line *line; 641 struct linereq *lr; 642 struct gpio_v2_line_event le; 643 u64 edflags; 644 int level; 645 646 if (!p) 647 return HTE_CB_HANDLED; 648 649 line = p; 650 lr = line->req; 651 652 memset(&le, 0, sizeof(le)); 653 654 le.timestamp_ns = line->timestamp_ns; 655 edflags = READ_ONCE(line->edflags); 656 657 switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) { 658 case GPIO_V2_LINE_FLAG_EDGE_BOTH: 659 level = (line->raw_level >= 0) ? 660 line->raw_level : 661 gpiod_get_raw_value_cansleep(line->desc); 662 663 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 664 level = !level; 665 666 le.id = line_event_id(level); 667 break; 668 case GPIO_V2_LINE_FLAG_EDGE_RISING: 669 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 670 break; 671 case GPIO_V2_LINE_FLAG_EDGE_FALLING: 672 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 673 break; 674 default: 675 return HTE_CB_HANDLED; 676 } 677 le.line_seqno = line->line_seqno; 678 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno; 679 le.offset = gpio_chip_hwgpio(line->desc); 680 681 linereq_put_event(lr, &le); 682 683 return HTE_CB_HANDLED; 684 } 685 686 static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p) 687 { 688 struct line *line; 689 struct linereq *lr; 690 int diff_seqno = 0; 691 692 if (!ts || !p) 693 return HTE_CB_HANDLED; 694 695 line = p; 696 line->timestamp_ns = ts->tsc; 697 line->raw_level = ts->raw_level; 698 lr = line->req; 699 700 if (READ_ONCE(line->sw_debounced)) { 701 line->total_discard_seq++; 702 line->last_seqno = ts->seq; 703 mod_delayed_work(system_wq, &line->work, 704 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); 705 } else { 706 if (unlikely(ts->seq < line->line_seqno)) 707 return HTE_CB_HANDLED; 708 709 diff_seqno = ts->seq - line->line_seqno; 710 line->line_seqno = ts->seq; 711 if (lr->num_lines != 1) 712 line->req_seqno = atomic_add_return(diff_seqno, 713 &lr->seqno); 714 715 return HTE_RUN_SECOND_CB; 716 } 717 718 return HTE_CB_HANDLED; 719 } 720 721 static int hte_edge_setup(struct line *line, u64 eflags) 722 { 723 int ret; 724 unsigned long flags = 0; 725 struct hte_ts_desc *hdesc = &line->hdesc; 726 727 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING) 728 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 729 HTE_FALLING_EDGE_TS : 730 HTE_RISING_EDGE_TS; 731 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING) 732 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 733 HTE_RISING_EDGE_TS : 734 HTE_FALLING_EDGE_TS; 735 736 line->total_discard_seq = 0; 737 738 hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL, 739 line->desc); 740 741 ret = hte_ts_get(NULL, hdesc, 0); 742 if (ret) 743 return ret; 744 745 return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread, 746 line); 747 } 748 749 #else 750 751 static int hte_edge_setup(struct line *line, u64 eflags) 752 { 753 return 0; 754 } 755 #endif /* CONFIG_HTE */ 756 757 static irqreturn_t edge_irq_thread(int irq, void *p) 758 { 759 struct line *line = p; 760 struct linereq *lr = line->req; 761 struct gpio_v2_line_event le; 762 763 /* Do not leak kernel stack to userspace */ 764 memset(&le, 0, sizeof(le)); 765 766 if (line->timestamp_ns) { 767 le.timestamp_ns = line->timestamp_ns; 768 } else { 769 /* 770 * We may be running from a nested threaded interrupt in 771 * which case we didn't get the timestamp from 772 * edge_irq_handler(). 773 */ 774 le.timestamp_ns = line_event_timestamp(line); 775 if (lr->num_lines != 1) 776 line->req_seqno = atomic_inc_return(&lr->seqno); 777 } 778 line->timestamp_ns = 0; 779 780 switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) { 781 case GPIO_V2_LINE_FLAG_EDGE_BOTH: 782 le.id = line_event_id(gpiod_get_value_cansleep(line->desc)); 783 break; 784 case GPIO_V2_LINE_FLAG_EDGE_RISING: 785 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 786 break; 787 case GPIO_V2_LINE_FLAG_EDGE_FALLING: 788 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 789 break; 790 default: 791 return IRQ_NONE; 792 } 793 line->line_seqno++; 794 le.line_seqno = line->line_seqno; 795 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno; 796 le.offset = gpio_chip_hwgpio(line->desc); 797 798 linereq_put_event(lr, &le); 799 800 return IRQ_HANDLED; 801 } 802 803 static irqreturn_t edge_irq_handler(int irq, void *p) 804 { 805 struct line *line = p; 806 struct linereq *lr = line->req; 807 808 /* 809 * Just store the timestamp in hardirq context so we get it as 810 * close in time as possible to the actual event. 811 */ 812 line->timestamp_ns = line_event_timestamp(line); 813 814 if (lr->num_lines != 1) 815 line->req_seqno = atomic_inc_return(&lr->seqno); 816 817 return IRQ_WAKE_THREAD; 818 } 819 820 /* 821 * returns the current debounced logical value. 822 */ 823 static bool debounced_value(struct line *line) 824 { 825 bool value; 826 827 /* 828 * minor race - debouncer may be stopped here, so edge_detector_stop() 829 * must leave the value unchanged so the following will read the level 830 * from when the debouncer was last running. 831 */ 832 value = READ_ONCE(line->level); 833 834 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags)) 835 value = !value; 836 837 return value; 838 } 839 840 static irqreturn_t debounce_irq_handler(int irq, void *p) 841 { 842 struct line *line = p; 843 844 mod_delayed_work(system_wq, &line->work, 845 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); 846 847 return IRQ_HANDLED; 848 } 849 850 static void debounce_work_func(struct work_struct *work) 851 { 852 struct gpio_v2_line_event le; 853 struct line *line = container_of(work, struct line, work.work); 854 struct linereq *lr; 855 u64 eflags, edflags = READ_ONCE(line->edflags); 856 int level = -1; 857 #ifdef CONFIG_HTE 858 int diff_seqno; 859 860 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) 861 level = line->raw_level; 862 #endif 863 if (level < 0) 864 level = gpiod_get_raw_value_cansleep(line->desc); 865 if (level < 0) { 866 pr_debug_ratelimited("debouncer failed to read line value\n"); 867 return; 868 } 869 870 if (READ_ONCE(line->level) == level) 871 return; 872 873 WRITE_ONCE(line->level, level); 874 875 /* -- edge detection -- */ 876 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS; 877 if (!eflags) 878 return; 879 880 /* switch from physical level to logical - if they differ */ 881 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 882 level = !level; 883 884 /* ignore edges that are not being monitored */ 885 if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) || 886 ((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level)) 887 return; 888 889 /* Do not leak kernel stack to userspace */ 890 memset(&le, 0, sizeof(le)); 891 892 lr = line->req; 893 le.timestamp_ns = line_event_timestamp(line); 894 le.offset = gpio_chip_hwgpio(line->desc); 895 #ifdef CONFIG_HTE 896 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) { 897 /* discard events except the last one */ 898 line->total_discard_seq -= 1; 899 diff_seqno = line->last_seqno - line->total_discard_seq - 900 line->line_seqno; 901 line->line_seqno = line->last_seqno - line->total_discard_seq; 902 le.line_seqno = line->line_seqno; 903 le.seqno = (lr->num_lines == 1) ? 904 le.line_seqno : atomic_add_return(diff_seqno, &lr->seqno); 905 } else 906 #endif /* CONFIG_HTE */ 907 { 908 line->line_seqno++; 909 le.line_seqno = line->line_seqno; 910 le.seqno = (lr->num_lines == 1) ? 911 le.line_seqno : atomic_inc_return(&lr->seqno); 912 } 913 914 le.id = line_event_id(level); 915 916 linereq_put_event(lr, &le); 917 } 918 919 static int debounce_setup(struct line *line, unsigned int debounce_period_us) 920 { 921 unsigned long irqflags; 922 int ret, level, irq; 923 char *label; 924 925 /* 926 * Try hardware. Skip gpiod_set_config() to avoid emitting two 927 * CHANGED_CONFIG line state events. 928 */ 929 ret = gpio_do_set_config(line->desc, 930 pinconf_to_config_packed(PIN_CONFIG_INPUT_DEBOUNCE, 931 debounce_period_us)); 932 if (ret != -ENOTSUPP) 933 return ret; 934 935 if (debounce_period_us) { 936 /* setup software debounce */ 937 level = gpiod_get_raw_value_cansleep(line->desc); 938 if (level < 0) 939 return level; 940 941 if (!(IS_ENABLED(CONFIG_HTE) && 942 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) { 943 irq = gpiod_to_irq(line->desc); 944 if (irq < 0) 945 return -ENXIO; 946 947 label = make_irq_label(line->req->label); 948 if (IS_ERR(label)) 949 return -ENOMEM; 950 951 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING; 952 ret = request_irq(irq, debounce_irq_handler, irqflags, 953 label, line); 954 if (ret) { 955 free_irq_label(label); 956 return ret; 957 } 958 line->irq = irq; 959 } else { 960 ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH); 961 if (ret) 962 return ret; 963 } 964 965 WRITE_ONCE(line->level, level); 966 WRITE_ONCE(line->sw_debounced, 1); 967 } 968 return 0; 969 } 970 971 static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc, 972 unsigned int line_idx) 973 { 974 unsigned int i; 975 u64 mask = BIT_ULL(line_idx); 976 977 for (i = 0; i < lc->num_attrs; i++) { 978 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 979 (lc->attrs[i].mask & mask)) 980 return true; 981 } 982 return false; 983 } 984 985 static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc, 986 unsigned int line_idx) 987 { 988 unsigned int i; 989 u64 mask = BIT_ULL(line_idx); 990 991 for (i = 0; i < lc->num_attrs; i++) { 992 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 993 (lc->attrs[i].mask & mask)) 994 return lc->attrs[i].attr.debounce_period_us; 995 } 996 return 0; 997 } 998 999 static void edge_detector_stop(struct line *line) 1000 { 1001 if (line->irq) { 1002 free_irq_label(free_irq(line->irq, line)); 1003 line->irq = 0; 1004 } 1005 1006 #ifdef CONFIG_HTE 1007 if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) 1008 hte_ts_put(&line->hdesc); 1009 #endif 1010 1011 cancel_delayed_work_sync(&line->work); 1012 WRITE_ONCE(line->sw_debounced, 0); 1013 WRITE_ONCE(line->edflags, 0); 1014 if (line->desc) 1015 WRITE_ONCE(line->desc->debounce_period_us, 0); 1016 /* do not change line->level - see comment in debounced_value() */ 1017 } 1018 1019 static int edge_detector_fifo_init(struct linereq *req) 1020 { 1021 if (kfifo_initialized(&req->events)) 1022 return 0; 1023 1024 return kfifo_alloc(&req->events, req->event_buffer_size, GFP_KERNEL); 1025 } 1026 1027 static int edge_detector_setup(struct line *line, 1028 struct gpio_v2_line_config *lc, 1029 unsigned int line_idx, u64 edflags) 1030 { 1031 u32 debounce_period_us; 1032 unsigned long irqflags = 0; 1033 u64 eflags; 1034 int irq, ret; 1035 char *label; 1036 1037 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS; 1038 if (eflags) { 1039 ret = edge_detector_fifo_init(line->req); 1040 if (ret) 1041 return ret; 1042 } 1043 if (gpio_v2_line_config_debounced(lc, line_idx)) { 1044 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx); 1045 ret = debounce_setup(line, debounce_period_us); 1046 if (ret) 1047 return ret; 1048 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 1049 } 1050 1051 /* detection disabled or sw debouncer will provide edge detection */ 1052 if (!eflags || READ_ONCE(line->sw_debounced)) 1053 return 0; 1054 1055 if (IS_ENABLED(CONFIG_HTE) && 1056 (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1057 return hte_edge_setup(line, edflags); 1058 1059 irq = gpiod_to_irq(line->desc); 1060 if (irq < 0) 1061 return -ENXIO; 1062 1063 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING) 1064 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 1065 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 1066 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING) 1067 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 1068 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 1069 irqflags |= IRQF_ONESHOT; 1070 1071 label = make_irq_label(line->req->label); 1072 if (IS_ERR(label)) 1073 return PTR_ERR(label); 1074 1075 /* Request a thread to read the events */ 1076 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread, 1077 irqflags, label, line); 1078 if (ret) { 1079 free_irq_label(label); 1080 return ret; 1081 } 1082 1083 line->irq = irq; 1084 return 0; 1085 } 1086 1087 static int edge_detector_update(struct line *line, 1088 struct gpio_v2_line_config *lc, 1089 unsigned int line_idx, u64 edflags) 1090 { 1091 u64 active_edflags = READ_ONCE(line->edflags); 1092 unsigned int debounce_period_us = 1093 gpio_v2_line_config_debounce_period(lc, line_idx); 1094 1095 if ((active_edflags == edflags) && 1096 (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us)) 1097 return 0; 1098 1099 /* sw debounced and still will be...*/ 1100 if (debounce_period_us && READ_ONCE(line->sw_debounced)) { 1101 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 1102 /* 1103 * ensure event fifo is initialised if edge detection 1104 * is now enabled. 1105 */ 1106 if (edflags & GPIO_V2_LINE_EDGE_FLAGS) 1107 return edge_detector_fifo_init(line->req); 1108 1109 return 0; 1110 } 1111 1112 /* reconfiguring edge detection or sw debounce being disabled */ 1113 if ((line->irq && !READ_ONCE(line->sw_debounced)) || 1114 (active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) || 1115 (!debounce_period_us && READ_ONCE(line->sw_debounced))) 1116 edge_detector_stop(line); 1117 1118 return edge_detector_setup(line, lc, line_idx, edflags); 1119 } 1120 1121 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc, 1122 unsigned int line_idx) 1123 { 1124 unsigned int i; 1125 u64 mask = BIT_ULL(line_idx); 1126 1127 for (i = 0; i < lc->num_attrs; i++) { 1128 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) && 1129 (lc->attrs[i].mask & mask)) 1130 return lc->attrs[i].attr.flags; 1131 } 1132 return lc->flags; 1133 } 1134 1135 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc, 1136 unsigned int line_idx) 1137 { 1138 unsigned int i; 1139 u64 mask = BIT_ULL(line_idx); 1140 1141 for (i = 0; i < lc->num_attrs; i++) { 1142 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) && 1143 (lc->attrs[i].mask & mask)) 1144 return !!(lc->attrs[i].attr.values & mask); 1145 } 1146 return 0; 1147 } 1148 1149 static int gpio_v2_line_flags_validate(u64 flags) 1150 { 1151 /* Return an error if an unknown flag is set */ 1152 if (flags & ~GPIO_V2_LINE_VALID_FLAGS) 1153 return -EINVAL; 1154 1155 if (!IS_ENABLED(CONFIG_HTE) && 1156 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1157 return -EOPNOTSUPP; 1158 1159 /* 1160 * Do not allow both INPUT and OUTPUT flags to be set as they are 1161 * contradictory. 1162 */ 1163 if ((flags & GPIO_V2_LINE_FLAG_INPUT) && 1164 (flags & GPIO_V2_LINE_FLAG_OUTPUT)) 1165 return -EINVAL; 1166 1167 /* Only allow one event clock source */ 1168 if (IS_ENABLED(CONFIG_HTE) && 1169 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME) && 1170 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1171 return -EINVAL; 1172 1173 /* Edge detection requires explicit input. */ 1174 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) && 1175 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 1176 return -EINVAL; 1177 1178 /* 1179 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single 1180 * request. If the hardware actually supports enabling both at the 1181 * same time the electrical result would be disastrous. 1182 */ 1183 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) && 1184 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE)) 1185 return -EINVAL; 1186 1187 /* Drive requires explicit output direction. */ 1188 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) && 1189 !(flags & GPIO_V2_LINE_FLAG_OUTPUT)) 1190 return -EINVAL; 1191 1192 /* Bias requires explicit direction. */ 1193 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) && 1194 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS)) 1195 return -EINVAL; 1196 1197 /* Only one bias flag can be set. */ 1198 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) && 1199 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | 1200 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) || 1201 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) && 1202 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) 1203 return -EINVAL; 1204 1205 return 0; 1206 } 1207 1208 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc, 1209 unsigned int num_lines) 1210 { 1211 unsigned int i; 1212 u64 flags; 1213 int ret; 1214 1215 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX) 1216 return -EINVAL; 1217 1218 if (!mem_is_zero(lc->padding, sizeof(lc->padding))) 1219 return -EINVAL; 1220 1221 for (i = 0; i < num_lines; i++) { 1222 flags = gpio_v2_line_config_flags(lc, i); 1223 ret = gpio_v2_line_flags_validate(flags); 1224 if (ret) 1225 return ret; 1226 1227 /* debounce requires explicit input */ 1228 if (gpio_v2_line_config_debounced(lc, i) && 1229 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 1230 return -EINVAL; 1231 } 1232 return 0; 1233 } 1234 1235 static void gpio_v2_line_config_flags_to_desc_flags(u64 lflags, 1236 unsigned long *flagsp) 1237 { 1238 unsigned long flags = READ_ONCE(*flagsp); 1239 1240 assign_bit(FLAG_ACTIVE_LOW, &flags, 1241 lflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW); 1242 1243 if (lflags & GPIO_V2_LINE_FLAG_OUTPUT) 1244 set_bit(FLAG_IS_OUT, &flags); 1245 else if (lflags & GPIO_V2_LINE_FLAG_INPUT) 1246 clear_bit(FLAG_IS_OUT, &flags); 1247 1248 assign_bit(FLAG_EDGE_RISING, &flags, 1249 lflags & GPIO_V2_LINE_FLAG_EDGE_RISING); 1250 assign_bit(FLAG_EDGE_FALLING, &flags, 1251 lflags & GPIO_V2_LINE_FLAG_EDGE_FALLING); 1252 1253 assign_bit(FLAG_OPEN_DRAIN, &flags, 1254 lflags & GPIO_V2_LINE_FLAG_OPEN_DRAIN); 1255 assign_bit(FLAG_OPEN_SOURCE, &flags, 1256 lflags & GPIO_V2_LINE_FLAG_OPEN_SOURCE); 1257 1258 assign_bit(FLAG_PULL_UP, &flags, 1259 lflags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP); 1260 assign_bit(FLAG_PULL_DOWN, &flags, 1261 lflags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN); 1262 assign_bit(FLAG_BIAS_DISABLE, &flags, 1263 lflags & GPIO_V2_LINE_FLAG_BIAS_DISABLED); 1264 1265 assign_bit(FLAG_EVENT_CLOCK_REALTIME, &flags, 1266 lflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME); 1267 assign_bit(FLAG_EVENT_CLOCK_HTE, &flags, 1268 lflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE); 1269 1270 WRITE_ONCE(*flagsp, flags); 1271 } 1272 1273 static long linereq_get_values(struct linereq *lr, void __user *ip) 1274 { 1275 struct gpio_v2_line_values lv; 1276 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1277 struct gpio_desc **descs; 1278 unsigned int i, didx, num_get; 1279 bool val; 1280 int ret; 1281 1282 /* NOTE: It's ok to read values of output lines. */ 1283 if (copy_from_user(&lv, ip, sizeof(lv))) 1284 return -EFAULT; 1285 1286 /* 1287 * gpiod_get_array_value_complex() requires compacted desc and val 1288 * arrays, rather than the sparse ones in lv. 1289 * Calculation of num_get and construction of the desc array is 1290 * optimized to avoid allocation for the desc array for the common 1291 * num_get == 1 case. 1292 */ 1293 /* scan requested lines to calculate the subset to get */ 1294 for (num_get = 0, i = 0; i < lr->num_lines; i++) { 1295 if (lv.mask & BIT_ULL(i)) { 1296 num_get++; 1297 /* capture desc for the num_get == 1 case */ 1298 descs = &lr->lines[i].desc; 1299 } 1300 } 1301 1302 if (num_get == 0) 1303 return -EINVAL; 1304 1305 if (num_get != 1) { 1306 /* build compacted desc array */ 1307 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL); 1308 if (!descs) 1309 return -ENOMEM; 1310 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1311 if (lv.mask & BIT_ULL(i)) { 1312 descs[didx] = lr->lines[i].desc; 1313 didx++; 1314 } 1315 } 1316 } 1317 ret = gpiod_get_array_value_complex(false, true, num_get, 1318 descs, NULL, vals); 1319 1320 if (num_get != 1) 1321 kfree(descs); 1322 if (ret) 1323 return ret; 1324 1325 lv.bits = 0; 1326 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1327 /* unpack compacted vals for the response */ 1328 if (lv.mask & BIT_ULL(i)) { 1329 if (lr->lines[i].sw_debounced) 1330 val = debounced_value(&lr->lines[i]); 1331 else 1332 val = test_bit(didx, vals); 1333 if (val) 1334 lv.bits |= BIT_ULL(i); 1335 didx++; 1336 } 1337 } 1338 1339 if (copy_to_user(ip, &lv, sizeof(lv))) 1340 return -EFAULT; 1341 1342 return 0; 1343 } 1344 1345 static long linereq_set_values(struct linereq *lr, void __user *ip) 1346 { 1347 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1348 struct gpio_v2_line_values lv; 1349 struct gpio_desc **descs; 1350 unsigned int i, didx, num_set; 1351 int ret; 1352 1353 if (copy_from_user(&lv, ip, sizeof(lv))) 1354 return -EFAULT; 1355 1356 guard(mutex)(&lr->config_mutex); 1357 1358 /* 1359 * gpiod_set_array_value_complex() requires compacted desc and val 1360 * arrays, rather than the sparse ones in lv. 1361 * Calculation of num_set and construction of the descs and vals arrays 1362 * is optimized to minimize scanning the lv->mask, and to avoid 1363 * allocation for the desc array for the common num_set == 1 case. 1364 */ 1365 bitmap_zero(vals, GPIO_V2_LINES_MAX); 1366 /* scan requested lines to determine the subset to be set */ 1367 for (num_set = 0, i = 0; i < lr->num_lines; i++) { 1368 if (lv.mask & BIT_ULL(i)) { 1369 /* add to compacted values */ 1370 if (lv.bits & BIT_ULL(i)) 1371 __set_bit(num_set, vals); 1372 num_set++; 1373 /* capture desc for the num_set == 1 case */ 1374 descs = &lr->lines[i].desc; 1375 } 1376 } 1377 if (num_set == 0) 1378 return -EINVAL; 1379 1380 if (num_set != 1) { 1381 /* build compacted desc array */ 1382 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL); 1383 if (!descs) 1384 return -ENOMEM; 1385 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1386 if (lv.mask & BIT_ULL(i)) { 1387 descs[didx] = lr->lines[i].desc; 1388 didx++; 1389 } 1390 } 1391 } 1392 ret = gpiod_set_array_value_complex(false, true, num_set, 1393 descs, NULL, vals); 1394 1395 if (num_set != 1) 1396 kfree(descs); 1397 return ret; 1398 } 1399 1400 static long linereq_set_config(struct linereq *lr, void __user *ip) 1401 { 1402 struct gpio_v2_line_config lc; 1403 struct gpio_desc *desc; 1404 struct line *line; 1405 unsigned int i; 1406 u64 flags, edflags; 1407 int ret; 1408 1409 if (copy_from_user(&lc, ip, sizeof(lc))) 1410 return -EFAULT; 1411 1412 ret = gpio_v2_line_config_validate(&lc, lr->num_lines); 1413 if (ret) 1414 return ret; 1415 1416 guard(mutex)(&lr->config_mutex); 1417 1418 for (i = 0; i < lr->num_lines; i++) { 1419 line = &lr->lines[i]; 1420 desc = lr->lines[i].desc; 1421 flags = gpio_v2_line_config_flags(&lc, i); 1422 /* 1423 * Lines not explicitly reconfigured as input or output 1424 * are left unchanged. 1425 */ 1426 if (!(flags & GPIO_V2_LINE_DIRECTION_FLAGS)) 1427 continue; 1428 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1429 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS; 1430 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1431 int val = gpio_v2_line_config_output_value(&lc, i); 1432 1433 edge_detector_stop(line); 1434 ret = gpiod_direction_output_nonotify(desc, val); 1435 if (ret) 1436 return ret; 1437 } else { 1438 ret = gpiod_direction_input_nonotify(desc); 1439 if (ret) 1440 return ret; 1441 1442 ret = edge_detector_update(line, &lc, i, edflags); 1443 if (ret) 1444 return ret; 1445 } 1446 1447 WRITE_ONCE(line->edflags, edflags); 1448 1449 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG); 1450 } 1451 return 0; 1452 } 1453 1454 static long linereq_ioctl(struct file *file, unsigned int cmd, 1455 unsigned long arg) 1456 { 1457 struct linereq *lr = file->private_data; 1458 void __user *ip = (void __user *)arg; 1459 1460 guard(srcu)(&lr->gdev->srcu); 1461 1462 if (!rcu_access_pointer(lr->gdev->chip)) 1463 return -ENODEV; 1464 1465 switch (cmd) { 1466 case GPIO_V2_LINE_GET_VALUES_IOCTL: 1467 return linereq_get_values(lr, ip); 1468 case GPIO_V2_LINE_SET_VALUES_IOCTL: 1469 return linereq_set_values(lr, ip); 1470 case GPIO_V2_LINE_SET_CONFIG_IOCTL: 1471 return linereq_set_config(lr, ip); 1472 default: 1473 return -EINVAL; 1474 } 1475 } 1476 1477 #ifdef CONFIG_COMPAT 1478 static long linereq_ioctl_compat(struct file *file, unsigned int cmd, 1479 unsigned long arg) 1480 { 1481 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1482 } 1483 #endif 1484 1485 static __poll_t linereq_poll(struct file *file, 1486 struct poll_table_struct *wait) 1487 { 1488 struct linereq *lr = file->private_data; 1489 __poll_t events = 0; 1490 1491 guard(srcu)(&lr->gdev->srcu); 1492 1493 if (!rcu_access_pointer(lr->gdev->chip)) 1494 return EPOLLHUP | EPOLLERR; 1495 1496 poll_wait(file, &lr->wait, wait); 1497 1498 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events, 1499 &lr->wait.lock)) 1500 events = EPOLLIN | EPOLLRDNORM; 1501 1502 return events; 1503 } 1504 1505 static ssize_t linereq_read(struct file *file, char __user *buf, 1506 size_t count, loff_t *f_ps) 1507 { 1508 struct linereq *lr = file->private_data; 1509 struct gpio_v2_line_event le; 1510 ssize_t bytes_read = 0; 1511 int ret; 1512 1513 guard(srcu)(&lr->gdev->srcu); 1514 1515 if (!rcu_access_pointer(lr->gdev->chip)) 1516 return -ENODEV; 1517 1518 if (count < sizeof(le)) 1519 return -EINVAL; 1520 1521 do { 1522 scoped_guard(spinlock, &lr->wait.lock) { 1523 if (kfifo_is_empty(&lr->events)) { 1524 if (bytes_read) 1525 return bytes_read; 1526 1527 if (file->f_flags & O_NONBLOCK) 1528 return -EAGAIN; 1529 1530 ret = wait_event_interruptible_locked(lr->wait, 1531 !kfifo_is_empty(&lr->events)); 1532 if (ret) 1533 return ret; 1534 } 1535 1536 if (kfifo_out(&lr->events, &le, 1) != 1) { 1537 /* 1538 * This should never happen - we hold the 1539 * lock from the moment we learned the fifo 1540 * is no longer empty until now. 1541 */ 1542 WARN(1, "failed to read from non-empty kfifo"); 1543 return -EIO; 1544 } 1545 } 1546 1547 if (copy_to_user(buf + bytes_read, &le, sizeof(le))) 1548 return -EFAULT; 1549 bytes_read += sizeof(le); 1550 } while (count >= bytes_read + sizeof(le)); 1551 1552 return bytes_read; 1553 } 1554 1555 static void linereq_free(struct linereq *lr) 1556 { 1557 unsigned int i; 1558 1559 if (lr->device_unregistered_nb.notifier_call) 1560 blocking_notifier_chain_unregister(&lr->gdev->device_notifier, 1561 &lr->device_unregistered_nb); 1562 1563 for (i = 0; i < lr->num_lines; i++) { 1564 if (lr->lines[i].desc) { 1565 edge_detector_stop(&lr->lines[i]); 1566 gpiod_free(lr->lines[i].desc); 1567 } 1568 } 1569 kfifo_free(&lr->events); 1570 kfree(lr->label); 1571 gpio_device_put(lr->gdev); 1572 kvfree(lr); 1573 } 1574 1575 static int linereq_release(struct inode *inode, struct file *file) 1576 { 1577 struct linereq *lr = file->private_data; 1578 1579 linereq_free(lr); 1580 return 0; 1581 } 1582 1583 #ifdef CONFIG_PROC_FS 1584 static void linereq_show_fdinfo(struct seq_file *out, struct file *file) 1585 { 1586 struct linereq *lr = file->private_data; 1587 struct device *dev = &lr->gdev->dev; 1588 u16 i; 1589 1590 seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev)); 1591 1592 for (i = 0; i < lr->num_lines; i++) 1593 seq_printf(out, "gpio-line:\t%d\n", 1594 gpio_chip_hwgpio(lr->lines[i].desc)); 1595 } 1596 #endif 1597 1598 static const struct file_operations line_fileops = { 1599 .release = linereq_release, 1600 .read = linereq_read, 1601 .poll = linereq_poll, 1602 .owner = THIS_MODULE, 1603 .llseek = noop_llseek, 1604 .unlocked_ioctl = linereq_ioctl, 1605 #ifdef CONFIG_COMPAT 1606 .compat_ioctl = linereq_ioctl_compat, 1607 #endif 1608 #ifdef CONFIG_PROC_FS 1609 .show_fdinfo = linereq_show_fdinfo, 1610 #endif 1611 }; 1612 1613 static int linereq_create(struct gpio_device *gdev, void __user *ip) 1614 { 1615 struct gpio_v2_line_request ulr; 1616 struct gpio_v2_line_config *lc; 1617 struct linereq *lr; 1618 struct file *file; 1619 u64 flags, edflags; 1620 unsigned int i; 1621 int fd, ret; 1622 1623 if (copy_from_user(&ulr, ip, sizeof(ulr))) 1624 return -EFAULT; 1625 1626 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX)) 1627 return -EINVAL; 1628 1629 if (!mem_is_zero(ulr.padding, sizeof(ulr.padding))) 1630 return -EINVAL; 1631 1632 lc = &ulr.config; 1633 ret = gpio_v2_line_config_validate(lc, ulr.num_lines); 1634 if (ret) 1635 return ret; 1636 1637 lr = kvzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL); 1638 if (!lr) 1639 return -ENOMEM; 1640 lr->num_lines = ulr.num_lines; 1641 1642 lr->gdev = gpio_device_get(gdev); 1643 1644 for (i = 0; i < ulr.num_lines; i++) { 1645 lr->lines[i].req = lr; 1646 WRITE_ONCE(lr->lines[i].sw_debounced, 0); 1647 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func); 1648 } 1649 1650 if (ulr.consumer[0] != '\0') { 1651 /* label is only initialized if consumer is set */ 1652 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1, 1653 GFP_KERNEL); 1654 if (!lr->label) { 1655 ret = -ENOMEM; 1656 goto out_free_linereq; 1657 } 1658 } 1659 1660 mutex_init(&lr->config_mutex); 1661 init_waitqueue_head(&lr->wait); 1662 INIT_KFIFO(lr->events); 1663 lr->event_buffer_size = ulr.event_buffer_size; 1664 if (lr->event_buffer_size == 0) 1665 lr->event_buffer_size = ulr.num_lines * 16; 1666 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16) 1667 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16; 1668 1669 atomic_set(&lr->seqno, 0); 1670 1671 /* Request each GPIO */ 1672 for (i = 0; i < ulr.num_lines; i++) { 1673 u32 offset = ulr.offsets[i]; 1674 struct gpio_desc *desc = gpio_device_get_desc(gdev, offset); 1675 1676 if (IS_ERR(desc)) { 1677 ret = PTR_ERR(desc); 1678 goto out_free_linereq; 1679 } 1680 1681 ret = gpiod_request_user(desc, lr->label); 1682 if (ret) 1683 goto out_free_linereq; 1684 1685 lr->lines[i].desc = desc; 1686 flags = gpio_v2_line_config_flags(lc, i); 1687 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1688 1689 ret = gpiod_set_transitory(desc, false); 1690 if (ret < 0) 1691 goto out_free_linereq; 1692 1693 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS; 1694 /* 1695 * Lines have to be requested explicitly for input 1696 * or output, else the line will be treated "as is". 1697 */ 1698 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1699 int val = gpio_v2_line_config_output_value(lc, i); 1700 1701 ret = gpiod_direction_output_nonotify(desc, val); 1702 if (ret) 1703 goto out_free_linereq; 1704 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1705 ret = gpiod_direction_input_nonotify(desc); 1706 if (ret) 1707 goto out_free_linereq; 1708 1709 ret = edge_detector_setup(&lr->lines[i], lc, i, 1710 edflags); 1711 if (ret) 1712 goto out_free_linereq; 1713 } 1714 1715 lr->lines[i].edflags = edflags; 1716 1717 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED); 1718 1719 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 1720 offset); 1721 } 1722 1723 lr->device_unregistered_nb.notifier_call = linereq_unregistered_notify; 1724 ret = blocking_notifier_chain_register(&gdev->device_notifier, 1725 &lr->device_unregistered_nb); 1726 if (ret) 1727 goto out_free_linereq; 1728 1729 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 1730 if (fd < 0) { 1731 ret = fd; 1732 goto out_free_linereq; 1733 } 1734 1735 file = anon_inode_getfile("gpio-line", &line_fileops, lr, 1736 O_RDONLY | O_CLOEXEC); 1737 if (IS_ERR(file)) { 1738 ret = PTR_ERR(file); 1739 goto out_put_unused_fd; 1740 } 1741 1742 ulr.fd = fd; 1743 if (copy_to_user(ip, &ulr, sizeof(ulr))) { 1744 /* 1745 * fput() will trigger the release() callback, so do not go onto 1746 * the regular error cleanup path here. 1747 */ 1748 fput(file); 1749 put_unused_fd(fd); 1750 return -EFAULT; 1751 } 1752 1753 fd_install(fd, file); 1754 1755 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 1756 lr->num_lines); 1757 1758 return 0; 1759 1760 out_put_unused_fd: 1761 put_unused_fd(fd); 1762 out_free_linereq: 1763 linereq_free(lr); 1764 return ret; 1765 } 1766 1767 #ifdef CONFIG_GPIO_CDEV_V1 1768 1769 /* 1770 * GPIO line event management 1771 */ 1772 1773 /** 1774 * struct lineevent_state - contains the state of a userspace event 1775 * @gdev: the GPIO device the event pertains to 1776 * @label: consumer label used to tag descriptors 1777 * @desc: the GPIO descriptor held by this event 1778 * @eflags: the event flags this line was requested with 1779 * @irq: the interrupt that trigger in response to events on this GPIO 1780 * @wait: wait queue that handles blocking reads of events 1781 * @device_unregistered_nb: notifier block for receiving gdev unregister events 1782 * @events: KFIFO for the GPIO events 1783 * @timestamp: cache for the timestamp storing it between hardirq 1784 * and IRQ thread, used to bring the timestamp close to the actual 1785 * event 1786 */ 1787 struct lineevent_state { 1788 struct gpio_device *gdev; 1789 const char *label; 1790 struct gpio_desc *desc; 1791 u32 eflags; 1792 int irq; 1793 wait_queue_head_t wait; 1794 struct notifier_block device_unregistered_nb; 1795 DECLARE_KFIFO(events, struct gpioevent_data, 16); 1796 u64 timestamp; 1797 }; 1798 1799 #define GPIOEVENT_REQUEST_VALID_FLAGS \ 1800 (GPIOEVENT_REQUEST_RISING_EDGE | \ 1801 GPIOEVENT_REQUEST_FALLING_EDGE) 1802 1803 static __poll_t lineevent_poll(struct file *file, 1804 struct poll_table_struct *wait) 1805 { 1806 struct lineevent_state *le = file->private_data; 1807 __poll_t events = 0; 1808 1809 guard(srcu)(&le->gdev->srcu); 1810 1811 if (!rcu_access_pointer(le->gdev->chip)) 1812 return EPOLLHUP | EPOLLERR; 1813 1814 poll_wait(file, &le->wait, wait); 1815 1816 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock)) 1817 events = EPOLLIN | EPOLLRDNORM; 1818 1819 return events; 1820 } 1821 1822 static int lineevent_unregistered_notify(struct notifier_block *nb, 1823 unsigned long action, void *data) 1824 { 1825 struct lineevent_state *le = container_of(nb, struct lineevent_state, 1826 device_unregistered_nb); 1827 1828 wake_up_poll(&le->wait, EPOLLIN | EPOLLERR); 1829 1830 return NOTIFY_OK; 1831 } 1832 1833 struct compat_gpioeevent_data { 1834 compat_u64 timestamp; 1835 u32 id; 1836 }; 1837 1838 static ssize_t lineevent_read(struct file *file, char __user *buf, 1839 size_t count, loff_t *f_ps) 1840 { 1841 struct lineevent_state *le = file->private_data; 1842 struct gpioevent_data ge; 1843 ssize_t bytes_read = 0; 1844 ssize_t ge_size; 1845 int ret; 1846 1847 guard(srcu)(&le->gdev->srcu); 1848 1849 if (!rcu_access_pointer(le->gdev->chip)) 1850 return -ENODEV; 1851 1852 /* 1853 * When compatible system call is being used the struct gpioevent_data, 1854 * in case of at least ia32, has different size due to the alignment 1855 * differences. Because we have first member 64 bits followed by one of 1856 * 32 bits there is no gap between them. The only difference is the 1857 * padding at the end of the data structure. Hence, we calculate the 1858 * actual sizeof() and pass this as an argument to copy_to_user() to 1859 * drop unneeded bytes from the output. 1860 */ 1861 if (compat_need_64bit_alignment_fixup()) 1862 ge_size = sizeof(struct compat_gpioeevent_data); 1863 else 1864 ge_size = sizeof(struct gpioevent_data); 1865 if (count < ge_size) 1866 return -EINVAL; 1867 1868 do { 1869 scoped_guard(spinlock, &le->wait.lock) { 1870 if (kfifo_is_empty(&le->events)) { 1871 if (bytes_read) 1872 return bytes_read; 1873 1874 if (file->f_flags & O_NONBLOCK) 1875 return -EAGAIN; 1876 1877 ret = wait_event_interruptible_locked(le->wait, 1878 !kfifo_is_empty(&le->events)); 1879 if (ret) 1880 return ret; 1881 } 1882 1883 if (kfifo_out(&le->events, &ge, 1) != 1) { 1884 /* 1885 * This should never happen - we hold the 1886 * lock from the moment we learned the fifo 1887 * is no longer empty until now. 1888 */ 1889 WARN(1, "failed to read from non-empty kfifo"); 1890 return -EIO; 1891 } 1892 } 1893 1894 if (copy_to_user(buf + bytes_read, &ge, ge_size)) 1895 return -EFAULT; 1896 bytes_read += ge_size; 1897 } while (count >= bytes_read + ge_size); 1898 1899 return bytes_read; 1900 } 1901 1902 static void lineevent_free(struct lineevent_state *le) 1903 { 1904 if (le->device_unregistered_nb.notifier_call) 1905 blocking_notifier_chain_unregister(&le->gdev->device_notifier, 1906 &le->device_unregistered_nb); 1907 if (le->irq) 1908 free_irq_label(free_irq(le->irq, le)); 1909 if (le->desc) 1910 gpiod_free(le->desc); 1911 kfree(le->label); 1912 gpio_device_put(le->gdev); 1913 kfree(le); 1914 } 1915 1916 static int lineevent_release(struct inode *inode, struct file *file) 1917 { 1918 lineevent_free(file->private_data); 1919 return 0; 1920 } 1921 1922 static long lineevent_ioctl(struct file *file, unsigned int cmd, 1923 unsigned long arg) 1924 { 1925 struct lineevent_state *le = file->private_data; 1926 void __user *ip = (void __user *)arg; 1927 struct gpiohandle_data ghd; 1928 1929 guard(srcu)(&le->gdev->srcu); 1930 1931 if (!rcu_access_pointer(le->gdev->chip)) 1932 return -ENODEV; 1933 1934 /* 1935 * We can get the value for an event line but not set it, 1936 * because it is input by definition. 1937 */ 1938 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { 1939 int val; 1940 1941 memset(&ghd, 0, sizeof(ghd)); 1942 1943 val = gpiod_get_value_cansleep(le->desc); 1944 if (val < 0) 1945 return val; 1946 ghd.values[0] = val; 1947 1948 if (copy_to_user(ip, &ghd, sizeof(ghd))) 1949 return -EFAULT; 1950 1951 return 0; 1952 } 1953 return -EINVAL; 1954 } 1955 1956 #ifdef CONFIG_COMPAT 1957 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd, 1958 unsigned long arg) 1959 { 1960 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1961 } 1962 #endif 1963 1964 static const struct file_operations lineevent_fileops = { 1965 .release = lineevent_release, 1966 .read = lineevent_read, 1967 .poll = lineevent_poll, 1968 .owner = THIS_MODULE, 1969 .llseek = noop_llseek, 1970 .unlocked_ioctl = lineevent_ioctl, 1971 #ifdef CONFIG_COMPAT 1972 .compat_ioctl = lineevent_ioctl_compat, 1973 #endif 1974 }; 1975 1976 static irqreturn_t lineevent_irq_thread(int irq, void *p) 1977 { 1978 struct lineevent_state *le = p; 1979 struct gpioevent_data ge; 1980 int ret; 1981 1982 /* Do not leak kernel stack to userspace */ 1983 memset(&ge, 0, sizeof(ge)); 1984 1985 /* 1986 * We may be running from a nested threaded interrupt in which case 1987 * we didn't get the timestamp from lineevent_irq_handler(). 1988 */ 1989 if (!le->timestamp) 1990 ge.timestamp = ktime_get_ns(); 1991 else 1992 ge.timestamp = le->timestamp; 1993 1994 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE 1995 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 1996 int level = gpiod_get_value_cansleep(le->desc); 1997 1998 if (level) 1999 /* Emit low-to-high event */ 2000 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 2001 else 2002 /* Emit high-to-low event */ 2003 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 2004 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) { 2005 /* Emit low-to-high event */ 2006 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 2007 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 2008 /* Emit high-to-low event */ 2009 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 2010 } else { 2011 return IRQ_NONE; 2012 } 2013 2014 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge, 2015 1, &le->wait.lock); 2016 if (ret) 2017 wake_up_poll(&le->wait, EPOLLIN); 2018 else 2019 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 2020 2021 return IRQ_HANDLED; 2022 } 2023 2024 static irqreturn_t lineevent_irq_handler(int irq, void *p) 2025 { 2026 struct lineevent_state *le = p; 2027 2028 /* 2029 * Just store the timestamp in hardirq context so we get it as 2030 * close in time as possible to the actual event. 2031 */ 2032 le->timestamp = ktime_get_ns(); 2033 2034 return IRQ_WAKE_THREAD; 2035 } 2036 2037 static int lineevent_create(struct gpio_device *gdev, void __user *ip) 2038 { 2039 struct gpioevent_request eventreq; 2040 struct lineevent_state *le; 2041 struct gpio_desc *desc; 2042 struct file *file; 2043 u32 offset; 2044 u32 lflags; 2045 u32 eflags; 2046 int fd; 2047 int ret; 2048 int irq, irqflags = 0; 2049 char *label; 2050 2051 if (copy_from_user(&eventreq, ip, sizeof(eventreq))) 2052 return -EFAULT; 2053 2054 offset = eventreq.lineoffset; 2055 lflags = eventreq.handleflags; 2056 eflags = eventreq.eventflags; 2057 2058 desc = gpio_device_get_desc(gdev, offset); 2059 if (IS_ERR(desc)) 2060 return PTR_ERR(desc); 2061 2062 /* Return an error if a unknown flag is set */ 2063 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) || 2064 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS)) 2065 return -EINVAL; 2066 2067 /* This is just wrong: we don't look for events on output lines */ 2068 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) || 2069 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 2070 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 2071 return -EINVAL; 2072 2073 /* Only one bias flag can be set. */ 2074 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 2075 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 2076 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 2077 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 2078 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 2079 return -EINVAL; 2080 2081 le = kzalloc(sizeof(*le), GFP_KERNEL); 2082 if (!le) 2083 return -ENOMEM; 2084 le->gdev = gpio_device_get(gdev); 2085 2086 if (eventreq.consumer_label[0] != '\0') { 2087 /* label is only initialized if consumer_label is set */ 2088 le->label = kstrndup(eventreq.consumer_label, 2089 sizeof(eventreq.consumer_label) - 1, 2090 GFP_KERNEL); 2091 if (!le->label) { 2092 ret = -ENOMEM; 2093 goto out_free_le; 2094 } 2095 } 2096 2097 ret = gpiod_request_user(desc, le->label); 2098 if (ret) 2099 goto out_free_le; 2100 le->desc = desc; 2101 le->eflags = eflags; 2102 2103 linehandle_flags_to_desc_flags(lflags, &desc->flags); 2104 2105 ret = gpiod_direction_input(desc); 2106 if (ret) 2107 goto out_free_le; 2108 2109 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED); 2110 2111 irq = gpiod_to_irq(desc); 2112 if (irq <= 0) { 2113 ret = -ENODEV; 2114 goto out_free_le; 2115 } 2116 2117 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE) 2118 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 2119 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 2120 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE) 2121 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 2122 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 2123 irqflags |= IRQF_ONESHOT; 2124 2125 INIT_KFIFO(le->events); 2126 init_waitqueue_head(&le->wait); 2127 2128 le->device_unregistered_nb.notifier_call = lineevent_unregistered_notify; 2129 ret = blocking_notifier_chain_register(&gdev->device_notifier, 2130 &le->device_unregistered_nb); 2131 if (ret) 2132 goto out_free_le; 2133 2134 label = make_irq_label(le->label); 2135 if (IS_ERR(label)) { 2136 ret = PTR_ERR(label); 2137 goto out_free_le; 2138 } 2139 2140 /* Request a thread to read the events */ 2141 ret = request_threaded_irq(irq, 2142 lineevent_irq_handler, 2143 lineevent_irq_thread, 2144 irqflags, 2145 label, 2146 le); 2147 if (ret) { 2148 free_irq_label(label); 2149 goto out_free_le; 2150 } 2151 2152 le->irq = irq; 2153 2154 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 2155 if (fd < 0) { 2156 ret = fd; 2157 goto out_free_le; 2158 } 2159 2160 file = anon_inode_getfile("gpio-event", 2161 &lineevent_fileops, 2162 le, 2163 O_RDONLY | O_CLOEXEC); 2164 if (IS_ERR(file)) { 2165 ret = PTR_ERR(file); 2166 goto out_put_unused_fd; 2167 } 2168 2169 eventreq.fd = fd; 2170 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) { 2171 /* 2172 * fput() will trigger the release() callback, so do not go onto 2173 * the regular error cleanup path here. 2174 */ 2175 fput(file); 2176 put_unused_fd(fd); 2177 return -EFAULT; 2178 } 2179 2180 fd_install(fd, file); 2181 2182 return 0; 2183 2184 out_put_unused_fd: 2185 put_unused_fd(fd); 2186 out_free_le: 2187 lineevent_free(le); 2188 return ret; 2189 } 2190 2191 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2, 2192 struct gpioline_info *info_v1) 2193 { 2194 u64 flagsv2 = info_v2->flags; 2195 2196 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name)); 2197 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer)); 2198 info_v1->line_offset = info_v2->offset; 2199 info_v1->flags = 0; 2200 2201 if (flagsv2 & GPIO_V2_LINE_FLAG_USED) 2202 info_v1->flags |= GPIOLINE_FLAG_KERNEL; 2203 2204 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT) 2205 info_v1->flags |= GPIOLINE_FLAG_IS_OUT; 2206 2207 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 2208 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW; 2209 2210 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN) 2211 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN; 2212 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE) 2213 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE; 2214 2215 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP) 2216 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP; 2217 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) 2218 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN; 2219 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED) 2220 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE; 2221 } 2222 2223 static void gpio_v2_line_info_changed_to_v1( 2224 struct gpio_v2_line_info_changed *lic_v2, 2225 struct gpioline_info_changed *lic_v1) 2226 { 2227 memset(lic_v1, 0, sizeof(*lic_v1)); 2228 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info); 2229 lic_v1->timestamp = lic_v2->timestamp_ns; 2230 lic_v1->event_type = lic_v2->event_type; 2231 } 2232 2233 #endif /* CONFIG_GPIO_CDEV_V1 */ 2234 2235 static void gpio_desc_to_lineinfo(struct gpio_desc *desc, 2236 struct gpio_v2_line_info *info, bool atomic) 2237 { 2238 u32 debounce_period_us; 2239 unsigned long dflags; 2240 const char *label; 2241 2242 CLASS(gpio_chip_guard, guard)(desc); 2243 if (!guard.gc) 2244 return; 2245 2246 memset(info, 0, sizeof(*info)); 2247 info->offset = gpio_chip_hwgpio(desc); 2248 2249 if (desc->name) 2250 strscpy(info->name, desc->name, sizeof(info->name)); 2251 2252 dflags = READ_ONCE(desc->flags); 2253 2254 scoped_guard(srcu, &desc->gdev->desc_srcu) { 2255 label = gpiod_get_label(desc); 2256 if (label && test_bit(FLAG_REQUESTED, &dflags)) 2257 strscpy(info->consumer, label, 2258 sizeof(info->consumer)); 2259 } 2260 2261 /* 2262 * Userspace only need know that the kernel is using this GPIO so it 2263 * can't use it. 2264 * The calculation of the used flag is slightly racy, as it may read 2265 * desc, gc and pinctrl state without a lock covering all three at 2266 * once. Worst case if the line is in transition and the calculation 2267 * is inconsistent then it looks to the user like they performed the 2268 * read on the other side of the transition - but that can always 2269 * happen. 2270 * The definitive test that a line is available to userspace is to 2271 * request it. 2272 */ 2273 if (test_bit(FLAG_REQUESTED, &dflags) || 2274 test_bit(FLAG_IS_HOGGED, &dflags) || 2275 test_bit(FLAG_EXPORT, &dflags) || 2276 test_bit(FLAG_SYSFS, &dflags) || 2277 !gpiochip_line_is_valid(guard.gc, info->offset)) { 2278 info->flags |= GPIO_V2_LINE_FLAG_USED; 2279 } else if (!atomic) { 2280 if (!pinctrl_gpio_can_use_line(guard.gc, info->offset)) 2281 info->flags |= GPIO_V2_LINE_FLAG_USED; 2282 } 2283 2284 if (test_bit(FLAG_IS_OUT, &dflags)) 2285 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT; 2286 else 2287 info->flags |= GPIO_V2_LINE_FLAG_INPUT; 2288 2289 if (test_bit(FLAG_ACTIVE_LOW, &dflags)) 2290 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW; 2291 2292 if (test_bit(FLAG_OPEN_DRAIN, &dflags)) 2293 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN; 2294 if (test_bit(FLAG_OPEN_SOURCE, &dflags)) 2295 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE; 2296 2297 if (test_bit(FLAG_BIAS_DISABLE, &dflags)) 2298 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED; 2299 if (test_bit(FLAG_PULL_DOWN, &dflags)) 2300 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN; 2301 if (test_bit(FLAG_PULL_UP, &dflags)) 2302 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP; 2303 2304 if (test_bit(FLAG_EDGE_RISING, &dflags)) 2305 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING; 2306 if (test_bit(FLAG_EDGE_FALLING, &dflags)) 2307 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING; 2308 2309 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &dflags)) 2310 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME; 2311 else if (test_bit(FLAG_EVENT_CLOCK_HTE, &dflags)) 2312 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE; 2313 2314 debounce_period_us = READ_ONCE(desc->debounce_period_us); 2315 if (debounce_period_us) { 2316 info->attrs[info->num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; 2317 info->attrs[info->num_attrs].debounce_period_us = 2318 debounce_period_us; 2319 info->num_attrs++; 2320 } 2321 } 2322 2323 struct gpio_chardev_data { 2324 struct gpio_device *gdev; 2325 wait_queue_head_t wait; 2326 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32); 2327 struct notifier_block lineinfo_changed_nb; 2328 struct notifier_block device_unregistered_nb; 2329 unsigned long *watched_lines; 2330 #ifdef CONFIG_GPIO_CDEV_V1 2331 atomic_t watch_abi_version; 2332 #endif 2333 struct file *fp; 2334 }; 2335 2336 static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip) 2337 { 2338 struct gpio_device *gdev = cdev->gdev; 2339 struct gpiochip_info chipinfo; 2340 2341 memset(&chipinfo, 0, sizeof(chipinfo)); 2342 2343 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name)); 2344 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label)); 2345 chipinfo.lines = gdev->ngpio; 2346 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo))) 2347 return -EFAULT; 2348 return 0; 2349 } 2350 2351 #ifdef CONFIG_GPIO_CDEV_V1 2352 /* 2353 * returns 0 if the versions match, else the previously selected ABI version 2354 */ 2355 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata, 2356 unsigned int version) 2357 { 2358 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version); 2359 2360 if (abiv == version) 2361 return 0; 2362 2363 return abiv; 2364 } 2365 2366 static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip, 2367 bool watch) 2368 { 2369 struct gpio_desc *desc; 2370 struct gpioline_info lineinfo; 2371 struct gpio_v2_line_info lineinfo_v2; 2372 2373 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2374 return -EFAULT; 2375 2376 /* this doubles as a range check on line_offset */ 2377 desc = gpio_device_get_desc(cdev->gdev, lineinfo.line_offset); 2378 if (IS_ERR(desc)) 2379 return PTR_ERR(desc); 2380 2381 if (watch) { 2382 if (lineinfo_ensure_abi_version(cdev, 1)) 2383 return -EPERM; 2384 2385 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines)) 2386 return -EBUSY; 2387 } 2388 2389 gpio_desc_to_lineinfo(desc, &lineinfo_v2, false); 2390 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); 2391 2392 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2393 if (watch) 2394 clear_bit(lineinfo.line_offset, cdev->watched_lines); 2395 return -EFAULT; 2396 } 2397 2398 return 0; 2399 } 2400 #endif 2401 2402 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, 2403 bool watch) 2404 { 2405 struct gpio_desc *desc; 2406 struct gpio_v2_line_info lineinfo; 2407 2408 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2409 return -EFAULT; 2410 2411 if (!mem_is_zero(lineinfo.padding, sizeof(lineinfo.padding))) 2412 return -EINVAL; 2413 2414 desc = gpio_device_get_desc(cdev->gdev, lineinfo.offset); 2415 if (IS_ERR(desc)) 2416 return PTR_ERR(desc); 2417 2418 if (watch) { 2419 #ifdef CONFIG_GPIO_CDEV_V1 2420 if (lineinfo_ensure_abi_version(cdev, 2)) 2421 return -EPERM; 2422 #endif 2423 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines)) 2424 return -EBUSY; 2425 } 2426 gpio_desc_to_lineinfo(desc, &lineinfo, false); 2427 2428 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2429 if (watch) 2430 clear_bit(lineinfo.offset, cdev->watched_lines); 2431 return -EFAULT; 2432 } 2433 2434 return 0; 2435 } 2436 2437 static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip) 2438 { 2439 __u32 offset; 2440 2441 if (copy_from_user(&offset, ip, sizeof(offset))) 2442 return -EFAULT; 2443 2444 if (offset >= cdev->gdev->ngpio) 2445 return -EINVAL; 2446 2447 if (!test_and_clear_bit(offset, cdev->watched_lines)) 2448 return -EBUSY; 2449 2450 return 0; 2451 } 2452 2453 /* 2454 * gpio_ioctl() - ioctl handler for the GPIO chardev 2455 */ 2456 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 2457 { 2458 struct gpio_chardev_data *cdev = file->private_data; 2459 struct gpio_device *gdev = cdev->gdev; 2460 void __user *ip = (void __user *)arg; 2461 2462 guard(srcu)(&gdev->srcu); 2463 2464 /* We fail any subsequent ioctl():s when the chip is gone */ 2465 if (!rcu_access_pointer(gdev->chip)) 2466 return -ENODEV; 2467 2468 /* Fill in the struct and pass to userspace */ 2469 switch (cmd) { 2470 case GPIO_GET_CHIPINFO_IOCTL: 2471 return chipinfo_get(cdev, ip); 2472 #ifdef CONFIG_GPIO_CDEV_V1 2473 case GPIO_GET_LINEHANDLE_IOCTL: 2474 return linehandle_create(gdev, ip); 2475 case GPIO_GET_LINEEVENT_IOCTL: 2476 return lineevent_create(gdev, ip); 2477 case GPIO_GET_LINEINFO_IOCTL: 2478 return lineinfo_get_v1(cdev, ip, false); 2479 case GPIO_GET_LINEINFO_WATCH_IOCTL: 2480 return lineinfo_get_v1(cdev, ip, true); 2481 #endif /* CONFIG_GPIO_CDEV_V1 */ 2482 case GPIO_V2_GET_LINEINFO_IOCTL: 2483 return lineinfo_get(cdev, ip, false); 2484 case GPIO_V2_GET_LINEINFO_WATCH_IOCTL: 2485 return lineinfo_get(cdev, ip, true); 2486 case GPIO_V2_GET_LINE_IOCTL: 2487 return linereq_create(gdev, ip); 2488 case GPIO_GET_LINEINFO_UNWATCH_IOCTL: 2489 return lineinfo_unwatch(cdev, ip); 2490 default: 2491 return -EINVAL; 2492 } 2493 } 2494 2495 #ifdef CONFIG_COMPAT 2496 static long gpio_ioctl_compat(struct file *file, unsigned int cmd, 2497 unsigned long arg) 2498 { 2499 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 2500 } 2501 #endif 2502 2503 struct lineinfo_changed_ctx { 2504 struct work_struct work; 2505 struct gpio_v2_line_info_changed chg; 2506 struct gpio_device *gdev; 2507 struct gpio_chardev_data *cdev; 2508 }; 2509 2510 static void lineinfo_changed_func(struct work_struct *work) 2511 { 2512 struct lineinfo_changed_ctx *ctx = 2513 container_of(work, struct lineinfo_changed_ctx, work); 2514 struct gpio_chip *gc; 2515 int ret; 2516 2517 if (!(ctx->chg.info.flags & GPIO_V2_LINE_FLAG_USED)) { 2518 /* 2519 * If nobody set the USED flag earlier, let's see with pinctrl 2520 * now. We're doing this late because it's a sleeping function. 2521 * Pin functions are in general much more static and while it's 2522 * not 100% bullet-proof, it's good enough for most cases. 2523 */ 2524 scoped_guard(srcu, &ctx->gdev->srcu) { 2525 gc = srcu_dereference(ctx->gdev->chip, &ctx->gdev->srcu); 2526 if (gc && 2527 !pinctrl_gpio_can_use_line(gc, ctx->chg.info.offset)) 2528 ctx->chg.info.flags |= GPIO_V2_LINE_FLAG_USED; 2529 } 2530 } 2531 2532 ret = kfifo_in_spinlocked(&ctx->cdev->events, &ctx->chg, 1, 2533 &ctx->cdev->wait.lock); 2534 if (ret) 2535 wake_up_poll(&ctx->cdev->wait, EPOLLIN); 2536 else 2537 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n"); 2538 2539 gpio_device_put(ctx->gdev); 2540 fput(ctx->cdev->fp); 2541 kfree(ctx); 2542 } 2543 2544 static int lineinfo_changed_notify(struct notifier_block *nb, 2545 unsigned long action, void *data) 2546 { 2547 struct gpio_chardev_data *cdev = 2548 container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb); 2549 struct lineinfo_changed_ctx *ctx; 2550 struct gpio_desc *desc = data; 2551 2552 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines)) 2553 return NOTIFY_DONE; 2554 2555 /* 2556 * If this is called from atomic context (for instance: with a spinlock 2557 * taken by the atomic notifier chain), any sleeping calls must be done 2558 * outside of this function in process context of the dedicated 2559 * workqueue. 2560 * 2561 * Let's gather as much info as possible from the descriptor and 2562 * postpone just the call to pinctrl_gpio_can_use_line() until the work 2563 * is executed. 2564 */ 2565 2566 ctx = kzalloc(sizeof(*ctx), GFP_ATOMIC); 2567 if (!ctx) { 2568 pr_err("Failed to allocate memory for line info notification\n"); 2569 return NOTIFY_DONE; 2570 } 2571 2572 ctx->chg.event_type = action; 2573 ctx->chg.timestamp_ns = ktime_get_ns(); 2574 gpio_desc_to_lineinfo(desc, &ctx->chg.info, true); 2575 /* Keep the GPIO device alive until we emit the event. */ 2576 ctx->gdev = gpio_device_get(desc->gdev); 2577 ctx->cdev = cdev; 2578 /* Keep the file descriptor alive too. */ 2579 get_file(ctx->cdev->fp); 2580 2581 INIT_WORK(&ctx->work, lineinfo_changed_func); 2582 queue_work(ctx->gdev->line_state_wq, &ctx->work); 2583 2584 return NOTIFY_OK; 2585 } 2586 2587 static int gpio_device_unregistered_notify(struct notifier_block *nb, 2588 unsigned long action, void *data) 2589 { 2590 struct gpio_chardev_data *cdev = container_of(nb, 2591 struct gpio_chardev_data, 2592 device_unregistered_nb); 2593 2594 wake_up_poll(&cdev->wait, EPOLLIN | EPOLLERR); 2595 2596 return NOTIFY_OK; 2597 } 2598 2599 static __poll_t lineinfo_watch_poll(struct file *file, 2600 struct poll_table_struct *pollt) 2601 { 2602 struct gpio_chardev_data *cdev = file->private_data; 2603 __poll_t events = 0; 2604 2605 guard(srcu)(&cdev->gdev->srcu); 2606 2607 if (!rcu_access_pointer(cdev->gdev->chip)) 2608 return EPOLLHUP | EPOLLERR; 2609 2610 poll_wait(file, &cdev->wait, pollt); 2611 2612 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events, 2613 &cdev->wait.lock)) 2614 events = EPOLLIN | EPOLLRDNORM; 2615 2616 return events; 2617 } 2618 2619 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, 2620 size_t count, loff_t *off) 2621 { 2622 struct gpio_chardev_data *cdev = file->private_data; 2623 struct gpio_v2_line_info_changed event; 2624 ssize_t bytes_read = 0; 2625 int ret; 2626 size_t event_size; 2627 2628 guard(srcu)(&cdev->gdev->srcu); 2629 2630 if (!rcu_access_pointer(cdev->gdev->chip)) 2631 return -ENODEV; 2632 2633 #ifndef CONFIG_GPIO_CDEV_V1 2634 event_size = sizeof(struct gpio_v2_line_info_changed); 2635 if (count < event_size) 2636 return -EINVAL; 2637 #endif 2638 2639 do { 2640 scoped_guard(spinlock, &cdev->wait.lock) { 2641 if (kfifo_is_empty(&cdev->events)) { 2642 if (bytes_read) 2643 return bytes_read; 2644 2645 if (file->f_flags & O_NONBLOCK) 2646 return -EAGAIN; 2647 2648 ret = wait_event_interruptible_locked(cdev->wait, 2649 !kfifo_is_empty(&cdev->events)); 2650 if (ret) 2651 return ret; 2652 } 2653 #ifdef CONFIG_GPIO_CDEV_V1 2654 /* must be after kfifo check so watch_abi_version is set */ 2655 if (atomic_read(&cdev->watch_abi_version) == 2) 2656 event_size = sizeof(struct gpio_v2_line_info_changed); 2657 else 2658 event_size = sizeof(struct gpioline_info_changed); 2659 if (count < event_size) 2660 return -EINVAL; 2661 #endif 2662 if (kfifo_out(&cdev->events, &event, 1) != 1) { 2663 /* 2664 * This should never happen - we hold the 2665 * lock from the moment we learned the fifo 2666 * is no longer empty until now. 2667 */ 2668 WARN(1, "failed to read from non-empty kfifo"); 2669 return -EIO; 2670 } 2671 } 2672 2673 #ifdef CONFIG_GPIO_CDEV_V1 2674 if (event_size == sizeof(struct gpio_v2_line_info_changed)) { 2675 if (copy_to_user(buf + bytes_read, &event, event_size)) 2676 return -EFAULT; 2677 } else { 2678 struct gpioline_info_changed event_v1; 2679 2680 gpio_v2_line_info_changed_to_v1(&event, &event_v1); 2681 if (copy_to_user(buf + bytes_read, &event_v1, 2682 event_size)) 2683 return -EFAULT; 2684 } 2685 #else 2686 if (copy_to_user(buf + bytes_read, &event, event_size)) 2687 return -EFAULT; 2688 #endif 2689 bytes_read += event_size; 2690 } while (count >= bytes_read + sizeof(event)); 2691 2692 return bytes_read; 2693 } 2694 2695 /** 2696 * gpio_chrdev_open() - open the chardev for ioctl operations 2697 * @inode: inode for this chardev 2698 * @file: file struct for storing private data 2699 * 2700 * Returns: 2701 * 0 on success, or negative errno on failure. 2702 */ 2703 static int gpio_chrdev_open(struct inode *inode, struct file *file) 2704 { 2705 struct gpio_device *gdev = container_of(inode->i_cdev, 2706 struct gpio_device, chrdev); 2707 struct gpio_chardev_data *cdev; 2708 int ret = -ENOMEM; 2709 2710 guard(srcu)(&gdev->srcu); 2711 2712 /* Fail on open if the backing gpiochip is gone */ 2713 if (!rcu_access_pointer(gdev->chip)) 2714 return -ENODEV; 2715 2716 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL); 2717 if (!cdev) 2718 return -ENODEV; 2719 2720 cdev->watched_lines = bitmap_zalloc(gdev->ngpio, GFP_KERNEL); 2721 if (!cdev->watched_lines) 2722 goto out_free_cdev; 2723 2724 init_waitqueue_head(&cdev->wait); 2725 INIT_KFIFO(cdev->events); 2726 cdev->gdev = gpio_device_get(gdev); 2727 2728 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify; 2729 scoped_guard(write_lock_irqsave, &gdev->line_state_lock) 2730 ret = raw_notifier_chain_register(&gdev->line_state_notifier, 2731 &cdev->lineinfo_changed_nb); 2732 if (ret) 2733 goto out_free_bitmap; 2734 2735 cdev->device_unregistered_nb.notifier_call = 2736 gpio_device_unregistered_notify; 2737 ret = blocking_notifier_chain_register(&gdev->device_notifier, 2738 &cdev->device_unregistered_nb); 2739 if (ret) 2740 goto out_unregister_line_notifier; 2741 2742 file->private_data = cdev; 2743 cdev->fp = file; 2744 2745 ret = nonseekable_open(inode, file); 2746 if (ret) 2747 goto out_unregister_device_notifier; 2748 2749 return ret; 2750 2751 out_unregister_device_notifier: 2752 blocking_notifier_chain_unregister(&gdev->device_notifier, 2753 &cdev->device_unregistered_nb); 2754 out_unregister_line_notifier: 2755 scoped_guard(write_lock_irqsave, &gdev->line_state_lock) 2756 raw_notifier_chain_unregister(&gdev->line_state_notifier, 2757 &cdev->lineinfo_changed_nb); 2758 out_free_bitmap: 2759 gpio_device_put(gdev); 2760 bitmap_free(cdev->watched_lines); 2761 out_free_cdev: 2762 kfree(cdev); 2763 return ret; 2764 } 2765 2766 /** 2767 * gpio_chrdev_release() - close chardev after ioctl operations 2768 * @inode: inode for this chardev 2769 * @file: file struct for storing private data 2770 * 2771 * Returns: 2772 * 0 on success, or negative errno on failure. 2773 */ 2774 static int gpio_chrdev_release(struct inode *inode, struct file *file) 2775 { 2776 struct gpio_chardev_data *cdev = file->private_data; 2777 struct gpio_device *gdev = cdev->gdev; 2778 2779 blocking_notifier_chain_unregister(&gdev->device_notifier, 2780 &cdev->device_unregistered_nb); 2781 scoped_guard(write_lock_irqsave, &gdev->line_state_lock) 2782 raw_notifier_chain_unregister(&gdev->line_state_notifier, 2783 &cdev->lineinfo_changed_nb); 2784 bitmap_free(cdev->watched_lines); 2785 gpio_device_put(gdev); 2786 kfree(cdev); 2787 2788 return 0; 2789 } 2790 2791 static const struct file_operations gpio_fileops = { 2792 .release = gpio_chrdev_release, 2793 .open = gpio_chrdev_open, 2794 .poll = lineinfo_watch_poll, 2795 .read = lineinfo_watch_read, 2796 .owner = THIS_MODULE, 2797 .unlocked_ioctl = gpio_ioctl, 2798 #ifdef CONFIG_COMPAT 2799 .compat_ioctl = gpio_ioctl_compat, 2800 #endif 2801 }; 2802 2803 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt) 2804 { 2805 struct gpio_chip *gc; 2806 int ret; 2807 2808 cdev_init(&gdev->chrdev, &gpio_fileops); 2809 gdev->chrdev.owner = THIS_MODULE; 2810 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id); 2811 2812 gdev->line_state_wq = alloc_ordered_workqueue("%s", WQ_HIGHPRI, 2813 dev_name(&gdev->dev)); 2814 if (!gdev->line_state_wq) 2815 return -ENOMEM; 2816 2817 ret = cdev_device_add(&gdev->chrdev, &gdev->dev); 2818 if (ret) 2819 return ret; 2820 2821 guard(srcu)(&gdev->srcu); 2822 gc = srcu_dereference(gdev->chip, &gdev->srcu); 2823 if (!gc) 2824 return -ENODEV; 2825 2826 chip_dbg(gc, "added GPIO chardev (%d:%d)\n", MAJOR(devt), gdev->id); 2827 2828 return 0; 2829 } 2830 2831 void gpiolib_cdev_unregister(struct gpio_device *gdev) 2832 { 2833 destroy_workqueue(gdev->line_state_wq); 2834 cdev_device_del(&gdev->chrdev, &gdev->dev); 2835 blocking_notifier_call_chain(&gdev->device_notifier, 0, NULL); 2836 } 2837