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 /* setting inputs is not allowed */ 1370 if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags)) 1371 return -EPERM; 1372 /* add to compacted values */ 1373 if (lv.bits & BIT_ULL(i)) 1374 __set_bit(num_set, vals); 1375 num_set++; 1376 /* capture desc for the num_set == 1 case */ 1377 descs = &lr->lines[i].desc; 1378 } 1379 } 1380 if (num_set == 0) 1381 return -EINVAL; 1382 1383 if (num_set != 1) { 1384 /* build compacted desc array */ 1385 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL); 1386 if (!descs) 1387 return -ENOMEM; 1388 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1389 if (lv.mask & BIT_ULL(i)) { 1390 descs[didx] = lr->lines[i].desc; 1391 didx++; 1392 } 1393 } 1394 } 1395 ret = gpiod_set_array_value_complex(false, true, num_set, 1396 descs, NULL, vals); 1397 1398 if (num_set != 1) 1399 kfree(descs); 1400 return ret; 1401 } 1402 1403 static long linereq_set_config(struct linereq *lr, void __user *ip) 1404 { 1405 struct gpio_v2_line_config lc; 1406 struct gpio_desc *desc; 1407 struct line *line; 1408 unsigned int i; 1409 u64 flags, edflags; 1410 int ret; 1411 1412 if (copy_from_user(&lc, ip, sizeof(lc))) 1413 return -EFAULT; 1414 1415 ret = gpio_v2_line_config_validate(&lc, lr->num_lines); 1416 if (ret) 1417 return ret; 1418 1419 guard(mutex)(&lr->config_mutex); 1420 1421 for (i = 0; i < lr->num_lines; i++) { 1422 line = &lr->lines[i]; 1423 desc = lr->lines[i].desc; 1424 flags = gpio_v2_line_config_flags(&lc, i); 1425 /* 1426 * Lines not explicitly reconfigured as input or output 1427 * are left unchanged. 1428 */ 1429 if (!(flags & GPIO_V2_LINE_DIRECTION_FLAGS)) 1430 continue; 1431 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1432 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS; 1433 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1434 int val = gpio_v2_line_config_output_value(&lc, i); 1435 1436 edge_detector_stop(line); 1437 ret = gpiod_direction_output_nonotify(desc, val); 1438 if (ret) 1439 return ret; 1440 } else { 1441 ret = gpiod_direction_input_nonotify(desc); 1442 if (ret) 1443 return ret; 1444 1445 ret = edge_detector_update(line, &lc, i, edflags); 1446 if (ret) 1447 return ret; 1448 } 1449 1450 WRITE_ONCE(line->edflags, edflags); 1451 1452 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG); 1453 } 1454 return 0; 1455 } 1456 1457 static long linereq_ioctl(struct file *file, unsigned int cmd, 1458 unsigned long arg) 1459 { 1460 struct linereq *lr = file->private_data; 1461 void __user *ip = (void __user *)arg; 1462 1463 guard(srcu)(&lr->gdev->srcu); 1464 1465 if (!rcu_access_pointer(lr->gdev->chip)) 1466 return -ENODEV; 1467 1468 switch (cmd) { 1469 case GPIO_V2_LINE_GET_VALUES_IOCTL: 1470 return linereq_get_values(lr, ip); 1471 case GPIO_V2_LINE_SET_VALUES_IOCTL: 1472 return linereq_set_values(lr, ip); 1473 case GPIO_V2_LINE_SET_CONFIG_IOCTL: 1474 return linereq_set_config(lr, ip); 1475 default: 1476 return -EINVAL; 1477 } 1478 } 1479 1480 #ifdef CONFIG_COMPAT 1481 static long linereq_ioctl_compat(struct file *file, unsigned int cmd, 1482 unsigned long arg) 1483 { 1484 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1485 } 1486 #endif 1487 1488 static __poll_t linereq_poll(struct file *file, 1489 struct poll_table_struct *wait) 1490 { 1491 struct linereq *lr = file->private_data; 1492 __poll_t events = 0; 1493 1494 guard(srcu)(&lr->gdev->srcu); 1495 1496 if (!rcu_access_pointer(lr->gdev->chip)) 1497 return EPOLLHUP | EPOLLERR; 1498 1499 poll_wait(file, &lr->wait, wait); 1500 1501 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events, 1502 &lr->wait.lock)) 1503 events = EPOLLIN | EPOLLRDNORM; 1504 1505 return events; 1506 } 1507 1508 static ssize_t linereq_read(struct file *file, char __user *buf, 1509 size_t count, loff_t *f_ps) 1510 { 1511 struct linereq *lr = file->private_data; 1512 struct gpio_v2_line_event le; 1513 ssize_t bytes_read = 0; 1514 int ret; 1515 1516 guard(srcu)(&lr->gdev->srcu); 1517 1518 if (!rcu_access_pointer(lr->gdev->chip)) 1519 return -ENODEV; 1520 1521 if (count < sizeof(le)) 1522 return -EINVAL; 1523 1524 do { 1525 scoped_guard(spinlock, &lr->wait.lock) { 1526 if (kfifo_is_empty(&lr->events)) { 1527 if (bytes_read) 1528 return bytes_read; 1529 1530 if (file->f_flags & O_NONBLOCK) 1531 return -EAGAIN; 1532 1533 ret = wait_event_interruptible_locked(lr->wait, 1534 !kfifo_is_empty(&lr->events)); 1535 if (ret) 1536 return ret; 1537 } 1538 1539 if (kfifo_out(&lr->events, &le, 1) != 1) { 1540 /* 1541 * This should never happen - we hold the 1542 * lock from the moment we learned the fifo 1543 * is no longer empty until now. 1544 */ 1545 WARN(1, "failed to read from non-empty kfifo"); 1546 return -EIO; 1547 } 1548 } 1549 1550 if (copy_to_user(buf + bytes_read, &le, sizeof(le))) 1551 return -EFAULT; 1552 bytes_read += sizeof(le); 1553 } while (count >= bytes_read + sizeof(le)); 1554 1555 return bytes_read; 1556 } 1557 1558 static void linereq_free(struct linereq *lr) 1559 { 1560 unsigned int i; 1561 1562 if (lr->device_unregistered_nb.notifier_call) 1563 blocking_notifier_chain_unregister(&lr->gdev->device_notifier, 1564 &lr->device_unregistered_nb); 1565 1566 for (i = 0; i < lr->num_lines; i++) { 1567 if (lr->lines[i].desc) { 1568 edge_detector_stop(&lr->lines[i]); 1569 gpiod_free(lr->lines[i].desc); 1570 } 1571 } 1572 kfifo_free(&lr->events); 1573 kfree(lr->label); 1574 gpio_device_put(lr->gdev); 1575 kvfree(lr); 1576 } 1577 1578 static int linereq_release(struct inode *inode, struct file *file) 1579 { 1580 struct linereq *lr = file->private_data; 1581 1582 linereq_free(lr); 1583 return 0; 1584 } 1585 1586 #ifdef CONFIG_PROC_FS 1587 static void linereq_show_fdinfo(struct seq_file *out, struct file *file) 1588 { 1589 struct linereq *lr = file->private_data; 1590 struct device *dev = &lr->gdev->dev; 1591 u16 i; 1592 1593 seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev)); 1594 1595 for (i = 0; i < lr->num_lines; i++) 1596 seq_printf(out, "gpio-line:\t%d\n", 1597 gpio_chip_hwgpio(lr->lines[i].desc)); 1598 } 1599 #endif 1600 1601 static const struct file_operations line_fileops = { 1602 .release = linereq_release, 1603 .read = linereq_read, 1604 .poll = linereq_poll, 1605 .owner = THIS_MODULE, 1606 .llseek = noop_llseek, 1607 .unlocked_ioctl = linereq_ioctl, 1608 #ifdef CONFIG_COMPAT 1609 .compat_ioctl = linereq_ioctl_compat, 1610 #endif 1611 #ifdef CONFIG_PROC_FS 1612 .show_fdinfo = linereq_show_fdinfo, 1613 #endif 1614 }; 1615 1616 static int linereq_create(struct gpio_device *gdev, void __user *ip) 1617 { 1618 struct gpio_v2_line_request ulr; 1619 struct gpio_v2_line_config *lc; 1620 struct linereq *lr; 1621 struct file *file; 1622 u64 flags, edflags; 1623 unsigned int i; 1624 int fd, ret; 1625 1626 if (copy_from_user(&ulr, ip, sizeof(ulr))) 1627 return -EFAULT; 1628 1629 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX)) 1630 return -EINVAL; 1631 1632 if (!mem_is_zero(ulr.padding, sizeof(ulr.padding))) 1633 return -EINVAL; 1634 1635 lc = &ulr.config; 1636 ret = gpio_v2_line_config_validate(lc, ulr.num_lines); 1637 if (ret) 1638 return ret; 1639 1640 lr = kvzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL); 1641 if (!lr) 1642 return -ENOMEM; 1643 lr->num_lines = ulr.num_lines; 1644 1645 lr->gdev = gpio_device_get(gdev); 1646 1647 for (i = 0; i < ulr.num_lines; i++) { 1648 lr->lines[i].req = lr; 1649 WRITE_ONCE(lr->lines[i].sw_debounced, 0); 1650 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func); 1651 } 1652 1653 if (ulr.consumer[0] != '\0') { 1654 /* label is only initialized if consumer is set */ 1655 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1, 1656 GFP_KERNEL); 1657 if (!lr->label) { 1658 ret = -ENOMEM; 1659 goto out_free_linereq; 1660 } 1661 } 1662 1663 mutex_init(&lr->config_mutex); 1664 init_waitqueue_head(&lr->wait); 1665 INIT_KFIFO(lr->events); 1666 lr->event_buffer_size = ulr.event_buffer_size; 1667 if (lr->event_buffer_size == 0) 1668 lr->event_buffer_size = ulr.num_lines * 16; 1669 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16) 1670 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16; 1671 1672 atomic_set(&lr->seqno, 0); 1673 1674 /* Request each GPIO */ 1675 for (i = 0; i < ulr.num_lines; i++) { 1676 u32 offset = ulr.offsets[i]; 1677 struct gpio_desc *desc = gpio_device_get_desc(gdev, offset); 1678 1679 if (IS_ERR(desc)) { 1680 ret = PTR_ERR(desc); 1681 goto out_free_linereq; 1682 } 1683 1684 ret = gpiod_request_user(desc, lr->label); 1685 if (ret) 1686 goto out_free_linereq; 1687 1688 lr->lines[i].desc = desc; 1689 flags = gpio_v2_line_config_flags(lc, i); 1690 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1691 1692 ret = gpiod_set_transitory(desc, false); 1693 if (ret < 0) 1694 goto out_free_linereq; 1695 1696 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS; 1697 /* 1698 * Lines have to be requested explicitly for input 1699 * or output, else the line will be treated "as is". 1700 */ 1701 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1702 int val = gpio_v2_line_config_output_value(lc, i); 1703 1704 ret = gpiod_direction_output_nonotify(desc, val); 1705 if (ret) 1706 goto out_free_linereq; 1707 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1708 ret = gpiod_direction_input_nonotify(desc); 1709 if (ret) 1710 goto out_free_linereq; 1711 1712 ret = edge_detector_setup(&lr->lines[i], lc, i, 1713 edflags); 1714 if (ret) 1715 goto out_free_linereq; 1716 } 1717 1718 lr->lines[i].edflags = edflags; 1719 1720 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED); 1721 1722 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 1723 offset); 1724 } 1725 1726 lr->device_unregistered_nb.notifier_call = linereq_unregistered_notify; 1727 ret = blocking_notifier_chain_register(&gdev->device_notifier, 1728 &lr->device_unregistered_nb); 1729 if (ret) 1730 goto out_free_linereq; 1731 1732 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 1733 if (fd < 0) { 1734 ret = fd; 1735 goto out_free_linereq; 1736 } 1737 1738 file = anon_inode_getfile("gpio-line", &line_fileops, lr, 1739 O_RDONLY | O_CLOEXEC); 1740 if (IS_ERR(file)) { 1741 ret = PTR_ERR(file); 1742 goto out_put_unused_fd; 1743 } 1744 1745 ulr.fd = fd; 1746 if (copy_to_user(ip, &ulr, sizeof(ulr))) { 1747 /* 1748 * fput() will trigger the release() callback, so do not go onto 1749 * the regular error cleanup path here. 1750 */ 1751 fput(file); 1752 put_unused_fd(fd); 1753 return -EFAULT; 1754 } 1755 1756 fd_install(fd, file); 1757 1758 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 1759 lr->num_lines); 1760 1761 return 0; 1762 1763 out_put_unused_fd: 1764 put_unused_fd(fd); 1765 out_free_linereq: 1766 linereq_free(lr); 1767 return ret; 1768 } 1769 1770 #ifdef CONFIG_GPIO_CDEV_V1 1771 1772 /* 1773 * GPIO line event management 1774 */ 1775 1776 /** 1777 * struct lineevent_state - contains the state of a userspace event 1778 * @gdev: the GPIO device the event pertains to 1779 * @label: consumer label used to tag descriptors 1780 * @desc: the GPIO descriptor held by this event 1781 * @eflags: the event flags this line was requested with 1782 * @irq: the interrupt that trigger in response to events on this GPIO 1783 * @wait: wait queue that handles blocking reads of events 1784 * @device_unregistered_nb: notifier block for receiving gdev unregister events 1785 * @events: KFIFO for the GPIO events 1786 * @timestamp: cache for the timestamp storing it between hardirq 1787 * and IRQ thread, used to bring the timestamp close to the actual 1788 * event 1789 */ 1790 struct lineevent_state { 1791 struct gpio_device *gdev; 1792 const char *label; 1793 struct gpio_desc *desc; 1794 u32 eflags; 1795 int irq; 1796 wait_queue_head_t wait; 1797 struct notifier_block device_unregistered_nb; 1798 DECLARE_KFIFO(events, struct gpioevent_data, 16); 1799 u64 timestamp; 1800 }; 1801 1802 #define GPIOEVENT_REQUEST_VALID_FLAGS \ 1803 (GPIOEVENT_REQUEST_RISING_EDGE | \ 1804 GPIOEVENT_REQUEST_FALLING_EDGE) 1805 1806 static __poll_t lineevent_poll(struct file *file, 1807 struct poll_table_struct *wait) 1808 { 1809 struct lineevent_state *le = file->private_data; 1810 __poll_t events = 0; 1811 1812 guard(srcu)(&le->gdev->srcu); 1813 1814 if (!rcu_access_pointer(le->gdev->chip)) 1815 return EPOLLHUP | EPOLLERR; 1816 1817 poll_wait(file, &le->wait, wait); 1818 1819 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock)) 1820 events = EPOLLIN | EPOLLRDNORM; 1821 1822 return events; 1823 } 1824 1825 static int lineevent_unregistered_notify(struct notifier_block *nb, 1826 unsigned long action, void *data) 1827 { 1828 struct lineevent_state *le = container_of(nb, struct lineevent_state, 1829 device_unregistered_nb); 1830 1831 wake_up_poll(&le->wait, EPOLLIN | EPOLLERR); 1832 1833 return NOTIFY_OK; 1834 } 1835 1836 struct compat_gpioeevent_data { 1837 compat_u64 timestamp; 1838 u32 id; 1839 }; 1840 1841 static ssize_t lineevent_read(struct file *file, char __user *buf, 1842 size_t count, loff_t *f_ps) 1843 { 1844 struct lineevent_state *le = file->private_data; 1845 struct gpioevent_data ge; 1846 ssize_t bytes_read = 0; 1847 ssize_t ge_size; 1848 int ret; 1849 1850 guard(srcu)(&le->gdev->srcu); 1851 1852 if (!rcu_access_pointer(le->gdev->chip)) 1853 return -ENODEV; 1854 1855 /* 1856 * When compatible system call is being used the struct gpioevent_data, 1857 * in case of at least ia32, has different size due to the alignment 1858 * differences. Because we have first member 64 bits followed by one of 1859 * 32 bits there is no gap between them. The only difference is the 1860 * padding at the end of the data structure. Hence, we calculate the 1861 * actual sizeof() and pass this as an argument to copy_to_user() to 1862 * drop unneeded bytes from the output. 1863 */ 1864 if (compat_need_64bit_alignment_fixup()) 1865 ge_size = sizeof(struct compat_gpioeevent_data); 1866 else 1867 ge_size = sizeof(struct gpioevent_data); 1868 if (count < ge_size) 1869 return -EINVAL; 1870 1871 do { 1872 scoped_guard(spinlock, &le->wait.lock) { 1873 if (kfifo_is_empty(&le->events)) { 1874 if (bytes_read) 1875 return bytes_read; 1876 1877 if (file->f_flags & O_NONBLOCK) 1878 return -EAGAIN; 1879 1880 ret = wait_event_interruptible_locked(le->wait, 1881 !kfifo_is_empty(&le->events)); 1882 if (ret) 1883 return ret; 1884 } 1885 1886 if (kfifo_out(&le->events, &ge, 1) != 1) { 1887 /* 1888 * This should never happen - we hold the 1889 * lock from the moment we learned the fifo 1890 * is no longer empty until now. 1891 */ 1892 WARN(1, "failed to read from non-empty kfifo"); 1893 return -EIO; 1894 } 1895 } 1896 1897 if (copy_to_user(buf + bytes_read, &ge, ge_size)) 1898 return -EFAULT; 1899 bytes_read += ge_size; 1900 } while (count >= bytes_read + ge_size); 1901 1902 return bytes_read; 1903 } 1904 1905 static void lineevent_free(struct lineevent_state *le) 1906 { 1907 if (le->device_unregistered_nb.notifier_call) 1908 blocking_notifier_chain_unregister(&le->gdev->device_notifier, 1909 &le->device_unregistered_nb); 1910 if (le->irq) 1911 free_irq_label(free_irq(le->irq, le)); 1912 if (le->desc) 1913 gpiod_free(le->desc); 1914 kfree(le->label); 1915 gpio_device_put(le->gdev); 1916 kfree(le); 1917 } 1918 1919 static int lineevent_release(struct inode *inode, struct file *file) 1920 { 1921 lineevent_free(file->private_data); 1922 return 0; 1923 } 1924 1925 static long lineevent_ioctl(struct file *file, unsigned int cmd, 1926 unsigned long arg) 1927 { 1928 struct lineevent_state *le = file->private_data; 1929 void __user *ip = (void __user *)arg; 1930 struct gpiohandle_data ghd; 1931 1932 guard(srcu)(&le->gdev->srcu); 1933 1934 if (!rcu_access_pointer(le->gdev->chip)) 1935 return -ENODEV; 1936 1937 /* 1938 * We can get the value for an event line but not set it, 1939 * because it is input by definition. 1940 */ 1941 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { 1942 int val; 1943 1944 memset(&ghd, 0, sizeof(ghd)); 1945 1946 val = gpiod_get_value_cansleep(le->desc); 1947 if (val < 0) 1948 return val; 1949 ghd.values[0] = val; 1950 1951 if (copy_to_user(ip, &ghd, sizeof(ghd))) 1952 return -EFAULT; 1953 1954 return 0; 1955 } 1956 return -EINVAL; 1957 } 1958 1959 #ifdef CONFIG_COMPAT 1960 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd, 1961 unsigned long arg) 1962 { 1963 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1964 } 1965 #endif 1966 1967 static const struct file_operations lineevent_fileops = { 1968 .release = lineevent_release, 1969 .read = lineevent_read, 1970 .poll = lineevent_poll, 1971 .owner = THIS_MODULE, 1972 .llseek = noop_llseek, 1973 .unlocked_ioctl = lineevent_ioctl, 1974 #ifdef CONFIG_COMPAT 1975 .compat_ioctl = lineevent_ioctl_compat, 1976 #endif 1977 }; 1978 1979 static irqreturn_t lineevent_irq_thread(int irq, void *p) 1980 { 1981 struct lineevent_state *le = p; 1982 struct gpioevent_data ge; 1983 int ret; 1984 1985 /* Do not leak kernel stack to userspace */ 1986 memset(&ge, 0, sizeof(ge)); 1987 1988 /* 1989 * We may be running from a nested threaded interrupt in which case 1990 * we didn't get the timestamp from lineevent_irq_handler(). 1991 */ 1992 if (!le->timestamp) 1993 ge.timestamp = ktime_get_ns(); 1994 else 1995 ge.timestamp = le->timestamp; 1996 1997 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE 1998 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 1999 int level = gpiod_get_value_cansleep(le->desc); 2000 2001 if (level) 2002 /* Emit low-to-high event */ 2003 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 2004 else 2005 /* Emit high-to-low event */ 2006 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 2007 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) { 2008 /* Emit low-to-high event */ 2009 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 2010 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 2011 /* Emit high-to-low event */ 2012 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 2013 } else { 2014 return IRQ_NONE; 2015 } 2016 2017 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge, 2018 1, &le->wait.lock); 2019 if (ret) 2020 wake_up_poll(&le->wait, EPOLLIN); 2021 else 2022 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 2023 2024 return IRQ_HANDLED; 2025 } 2026 2027 static irqreturn_t lineevent_irq_handler(int irq, void *p) 2028 { 2029 struct lineevent_state *le = p; 2030 2031 /* 2032 * Just store the timestamp in hardirq context so we get it as 2033 * close in time as possible to the actual event. 2034 */ 2035 le->timestamp = ktime_get_ns(); 2036 2037 return IRQ_WAKE_THREAD; 2038 } 2039 2040 static int lineevent_create(struct gpio_device *gdev, void __user *ip) 2041 { 2042 struct gpioevent_request eventreq; 2043 struct lineevent_state *le; 2044 struct gpio_desc *desc; 2045 struct file *file; 2046 u32 offset; 2047 u32 lflags; 2048 u32 eflags; 2049 int fd; 2050 int ret; 2051 int irq, irqflags = 0; 2052 char *label; 2053 2054 if (copy_from_user(&eventreq, ip, sizeof(eventreq))) 2055 return -EFAULT; 2056 2057 offset = eventreq.lineoffset; 2058 lflags = eventreq.handleflags; 2059 eflags = eventreq.eventflags; 2060 2061 desc = gpio_device_get_desc(gdev, offset); 2062 if (IS_ERR(desc)) 2063 return PTR_ERR(desc); 2064 2065 /* Return an error if a unknown flag is set */ 2066 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) || 2067 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS)) 2068 return -EINVAL; 2069 2070 /* This is just wrong: we don't look for events on output lines */ 2071 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) || 2072 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 2073 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 2074 return -EINVAL; 2075 2076 /* Only one bias flag can be set. */ 2077 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 2078 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 2079 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 2080 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 2081 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 2082 return -EINVAL; 2083 2084 le = kzalloc(sizeof(*le), GFP_KERNEL); 2085 if (!le) 2086 return -ENOMEM; 2087 le->gdev = gpio_device_get(gdev); 2088 2089 if (eventreq.consumer_label[0] != '\0') { 2090 /* label is only initialized if consumer_label is set */ 2091 le->label = kstrndup(eventreq.consumer_label, 2092 sizeof(eventreq.consumer_label) - 1, 2093 GFP_KERNEL); 2094 if (!le->label) { 2095 ret = -ENOMEM; 2096 goto out_free_le; 2097 } 2098 } 2099 2100 ret = gpiod_request_user(desc, le->label); 2101 if (ret) 2102 goto out_free_le; 2103 le->desc = desc; 2104 le->eflags = eflags; 2105 2106 linehandle_flags_to_desc_flags(lflags, &desc->flags); 2107 2108 ret = gpiod_direction_input(desc); 2109 if (ret) 2110 goto out_free_le; 2111 2112 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED); 2113 2114 irq = gpiod_to_irq(desc); 2115 if (irq <= 0) { 2116 ret = -ENODEV; 2117 goto out_free_le; 2118 } 2119 2120 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE) 2121 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 2122 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 2123 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE) 2124 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 2125 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 2126 irqflags |= IRQF_ONESHOT; 2127 2128 INIT_KFIFO(le->events); 2129 init_waitqueue_head(&le->wait); 2130 2131 le->device_unregistered_nb.notifier_call = lineevent_unregistered_notify; 2132 ret = blocking_notifier_chain_register(&gdev->device_notifier, 2133 &le->device_unregistered_nb); 2134 if (ret) 2135 goto out_free_le; 2136 2137 label = make_irq_label(le->label); 2138 if (IS_ERR(label)) { 2139 ret = PTR_ERR(label); 2140 goto out_free_le; 2141 } 2142 2143 /* Request a thread to read the events */ 2144 ret = request_threaded_irq(irq, 2145 lineevent_irq_handler, 2146 lineevent_irq_thread, 2147 irqflags, 2148 label, 2149 le); 2150 if (ret) { 2151 free_irq_label(label); 2152 goto out_free_le; 2153 } 2154 2155 le->irq = irq; 2156 2157 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 2158 if (fd < 0) { 2159 ret = fd; 2160 goto out_free_le; 2161 } 2162 2163 file = anon_inode_getfile("gpio-event", 2164 &lineevent_fileops, 2165 le, 2166 O_RDONLY | O_CLOEXEC); 2167 if (IS_ERR(file)) { 2168 ret = PTR_ERR(file); 2169 goto out_put_unused_fd; 2170 } 2171 2172 eventreq.fd = fd; 2173 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) { 2174 /* 2175 * fput() will trigger the release() callback, so do not go onto 2176 * the regular error cleanup path here. 2177 */ 2178 fput(file); 2179 put_unused_fd(fd); 2180 return -EFAULT; 2181 } 2182 2183 fd_install(fd, file); 2184 2185 return 0; 2186 2187 out_put_unused_fd: 2188 put_unused_fd(fd); 2189 out_free_le: 2190 lineevent_free(le); 2191 return ret; 2192 } 2193 2194 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2, 2195 struct gpioline_info *info_v1) 2196 { 2197 u64 flagsv2 = info_v2->flags; 2198 2199 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name)); 2200 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer)); 2201 info_v1->line_offset = info_v2->offset; 2202 info_v1->flags = 0; 2203 2204 if (flagsv2 & GPIO_V2_LINE_FLAG_USED) 2205 info_v1->flags |= GPIOLINE_FLAG_KERNEL; 2206 2207 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT) 2208 info_v1->flags |= GPIOLINE_FLAG_IS_OUT; 2209 2210 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 2211 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW; 2212 2213 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN) 2214 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN; 2215 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE) 2216 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE; 2217 2218 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP) 2219 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP; 2220 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) 2221 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN; 2222 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED) 2223 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE; 2224 } 2225 2226 static void gpio_v2_line_info_changed_to_v1( 2227 struct gpio_v2_line_info_changed *lic_v2, 2228 struct gpioline_info_changed *lic_v1) 2229 { 2230 memset(lic_v1, 0, sizeof(*lic_v1)); 2231 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info); 2232 lic_v1->timestamp = lic_v2->timestamp_ns; 2233 lic_v1->event_type = lic_v2->event_type; 2234 } 2235 2236 #endif /* CONFIG_GPIO_CDEV_V1 */ 2237 2238 static void gpio_desc_to_lineinfo(struct gpio_desc *desc, 2239 struct gpio_v2_line_info *info, bool atomic) 2240 { 2241 u32 debounce_period_us; 2242 unsigned long dflags; 2243 const char *label; 2244 2245 CLASS(gpio_chip_guard, guard)(desc); 2246 if (!guard.gc) 2247 return; 2248 2249 memset(info, 0, sizeof(*info)); 2250 info->offset = gpio_chip_hwgpio(desc); 2251 2252 if (desc->name) 2253 strscpy(info->name, desc->name, sizeof(info->name)); 2254 2255 dflags = READ_ONCE(desc->flags); 2256 2257 scoped_guard(srcu, &desc->gdev->desc_srcu) { 2258 label = gpiod_get_label(desc); 2259 if (label && test_bit(FLAG_REQUESTED, &dflags)) 2260 strscpy(info->consumer, label, 2261 sizeof(info->consumer)); 2262 } 2263 2264 /* 2265 * Userspace only need know that the kernel is using this GPIO so it 2266 * can't use it. 2267 * The calculation of the used flag is slightly racy, as it may read 2268 * desc, gc and pinctrl state without a lock covering all three at 2269 * once. Worst case if the line is in transition and the calculation 2270 * is inconsistent then it looks to the user like they performed the 2271 * read on the other side of the transition - but that can always 2272 * happen. 2273 * The definitive test that a line is available to userspace is to 2274 * request it. 2275 */ 2276 if (test_bit(FLAG_REQUESTED, &dflags) || 2277 test_bit(FLAG_IS_HOGGED, &dflags) || 2278 test_bit(FLAG_EXPORT, &dflags) || 2279 test_bit(FLAG_SYSFS, &dflags) || 2280 !gpiochip_line_is_valid(guard.gc, info->offset)) { 2281 info->flags |= GPIO_V2_LINE_FLAG_USED; 2282 } else if (!atomic) { 2283 if (!pinctrl_gpio_can_use_line(guard.gc, info->offset)) 2284 info->flags |= GPIO_V2_LINE_FLAG_USED; 2285 } 2286 2287 if (test_bit(FLAG_IS_OUT, &dflags)) 2288 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT; 2289 else 2290 info->flags |= GPIO_V2_LINE_FLAG_INPUT; 2291 2292 if (test_bit(FLAG_ACTIVE_LOW, &dflags)) 2293 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW; 2294 2295 if (test_bit(FLAG_OPEN_DRAIN, &dflags)) 2296 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN; 2297 if (test_bit(FLAG_OPEN_SOURCE, &dflags)) 2298 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE; 2299 2300 if (test_bit(FLAG_BIAS_DISABLE, &dflags)) 2301 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED; 2302 if (test_bit(FLAG_PULL_DOWN, &dflags)) 2303 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN; 2304 if (test_bit(FLAG_PULL_UP, &dflags)) 2305 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP; 2306 2307 if (test_bit(FLAG_EDGE_RISING, &dflags)) 2308 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING; 2309 if (test_bit(FLAG_EDGE_FALLING, &dflags)) 2310 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING; 2311 2312 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &dflags)) 2313 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME; 2314 else if (test_bit(FLAG_EVENT_CLOCK_HTE, &dflags)) 2315 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE; 2316 2317 debounce_period_us = READ_ONCE(desc->debounce_period_us); 2318 if (debounce_period_us) { 2319 info->attrs[info->num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; 2320 info->attrs[info->num_attrs].debounce_period_us = 2321 debounce_period_us; 2322 info->num_attrs++; 2323 } 2324 } 2325 2326 struct gpio_chardev_data { 2327 struct gpio_device *gdev; 2328 wait_queue_head_t wait; 2329 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32); 2330 struct notifier_block lineinfo_changed_nb; 2331 struct notifier_block device_unregistered_nb; 2332 unsigned long *watched_lines; 2333 #ifdef CONFIG_GPIO_CDEV_V1 2334 atomic_t watch_abi_version; 2335 #endif 2336 struct file *fp; 2337 }; 2338 2339 static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip) 2340 { 2341 struct gpio_device *gdev = cdev->gdev; 2342 struct gpiochip_info chipinfo; 2343 2344 memset(&chipinfo, 0, sizeof(chipinfo)); 2345 2346 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name)); 2347 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label)); 2348 chipinfo.lines = gdev->ngpio; 2349 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo))) 2350 return -EFAULT; 2351 return 0; 2352 } 2353 2354 #ifdef CONFIG_GPIO_CDEV_V1 2355 /* 2356 * returns 0 if the versions match, else the previously selected ABI version 2357 */ 2358 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata, 2359 unsigned int version) 2360 { 2361 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version); 2362 2363 if (abiv == version) 2364 return 0; 2365 2366 return abiv; 2367 } 2368 2369 static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip, 2370 bool watch) 2371 { 2372 struct gpio_desc *desc; 2373 struct gpioline_info lineinfo; 2374 struct gpio_v2_line_info lineinfo_v2; 2375 2376 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2377 return -EFAULT; 2378 2379 /* this doubles as a range check on line_offset */ 2380 desc = gpio_device_get_desc(cdev->gdev, lineinfo.line_offset); 2381 if (IS_ERR(desc)) 2382 return PTR_ERR(desc); 2383 2384 if (watch) { 2385 if (lineinfo_ensure_abi_version(cdev, 1)) 2386 return -EPERM; 2387 2388 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines)) 2389 return -EBUSY; 2390 } 2391 2392 gpio_desc_to_lineinfo(desc, &lineinfo_v2, false); 2393 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); 2394 2395 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2396 if (watch) 2397 clear_bit(lineinfo.line_offset, cdev->watched_lines); 2398 return -EFAULT; 2399 } 2400 2401 return 0; 2402 } 2403 #endif 2404 2405 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, 2406 bool watch) 2407 { 2408 struct gpio_desc *desc; 2409 struct gpio_v2_line_info lineinfo; 2410 2411 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2412 return -EFAULT; 2413 2414 if (!mem_is_zero(lineinfo.padding, sizeof(lineinfo.padding))) 2415 return -EINVAL; 2416 2417 desc = gpio_device_get_desc(cdev->gdev, lineinfo.offset); 2418 if (IS_ERR(desc)) 2419 return PTR_ERR(desc); 2420 2421 if (watch) { 2422 #ifdef CONFIG_GPIO_CDEV_V1 2423 if (lineinfo_ensure_abi_version(cdev, 2)) 2424 return -EPERM; 2425 #endif 2426 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines)) 2427 return -EBUSY; 2428 } 2429 gpio_desc_to_lineinfo(desc, &lineinfo, false); 2430 2431 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2432 if (watch) 2433 clear_bit(lineinfo.offset, cdev->watched_lines); 2434 return -EFAULT; 2435 } 2436 2437 return 0; 2438 } 2439 2440 static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip) 2441 { 2442 __u32 offset; 2443 2444 if (copy_from_user(&offset, ip, sizeof(offset))) 2445 return -EFAULT; 2446 2447 if (offset >= cdev->gdev->ngpio) 2448 return -EINVAL; 2449 2450 if (!test_and_clear_bit(offset, cdev->watched_lines)) 2451 return -EBUSY; 2452 2453 return 0; 2454 } 2455 2456 /* 2457 * gpio_ioctl() - ioctl handler for the GPIO chardev 2458 */ 2459 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 2460 { 2461 struct gpio_chardev_data *cdev = file->private_data; 2462 struct gpio_device *gdev = cdev->gdev; 2463 void __user *ip = (void __user *)arg; 2464 2465 guard(srcu)(&gdev->srcu); 2466 2467 /* We fail any subsequent ioctl():s when the chip is gone */ 2468 if (!rcu_access_pointer(gdev->chip)) 2469 return -ENODEV; 2470 2471 /* Fill in the struct and pass to userspace */ 2472 switch (cmd) { 2473 case GPIO_GET_CHIPINFO_IOCTL: 2474 return chipinfo_get(cdev, ip); 2475 #ifdef CONFIG_GPIO_CDEV_V1 2476 case GPIO_GET_LINEHANDLE_IOCTL: 2477 return linehandle_create(gdev, ip); 2478 case GPIO_GET_LINEEVENT_IOCTL: 2479 return lineevent_create(gdev, ip); 2480 case GPIO_GET_LINEINFO_IOCTL: 2481 return lineinfo_get_v1(cdev, ip, false); 2482 case GPIO_GET_LINEINFO_WATCH_IOCTL: 2483 return lineinfo_get_v1(cdev, ip, true); 2484 #endif /* CONFIG_GPIO_CDEV_V1 */ 2485 case GPIO_V2_GET_LINEINFO_IOCTL: 2486 return lineinfo_get(cdev, ip, false); 2487 case GPIO_V2_GET_LINEINFO_WATCH_IOCTL: 2488 return lineinfo_get(cdev, ip, true); 2489 case GPIO_V2_GET_LINE_IOCTL: 2490 return linereq_create(gdev, ip); 2491 case GPIO_GET_LINEINFO_UNWATCH_IOCTL: 2492 return lineinfo_unwatch(cdev, ip); 2493 default: 2494 return -EINVAL; 2495 } 2496 } 2497 2498 #ifdef CONFIG_COMPAT 2499 static long gpio_ioctl_compat(struct file *file, unsigned int cmd, 2500 unsigned long arg) 2501 { 2502 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 2503 } 2504 #endif 2505 2506 struct lineinfo_changed_ctx { 2507 struct work_struct work; 2508 struct gpio_v2_line_info_changed chg; 2509 struct gpio_device *gdev; 2510 struct gpio_chardev_data *cdev; 2511 }; 2512 2513 static void lineinfo_changed_func(struct work_struct *work) 2514 { 2515 struct lineinfo_changed_ctx *ctx = 2516 container_of(work, struct lineinfo_changed_ctx, work); 2517 struct gpio_chip *gc; 2518 int ret; 2519 2520 if (!(ctx->chg.info.flags & GPIO_V2_LINE_FLAG_USED)) { 2521 /* 2522 * If nobody set the USED flag earlier, let's see with pinctrl 2523 * now. We're doing this late because it's a sleeping function. 2524 * Pin functions are in general much more static and while it's 2525 * not 100% bullet-proof, it's good enough for most cases. 2526 */ 2527 scoped_guard(srcu, &ctx->gdev->srcu) { 2528 gc = srcu_dereference(ctx->gdev->chip, &ctx->gdev->srcu); 2529 if (gc && 2530 !pinctrl_gpio_can_use_line(gc, ctx->chg.info.offset)) 2531 ctx->chg.info.flags |= GPIO_V2_LINE_FLAG_USED; 2532 } 2533 } 2534 2535 ret = kfifo_in_spinlocked(&ctx->cdev->events, &ctx->chg, 1, 2536 &ctx->cdev->wait.lock); 2537 if (ret) 2538 wake_up_poll(&ctx->cdev->wait, EPOLLIN); 2539 else 2540 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n"); 2541 2542 gpio_device_put(ctx->gdev); 2543 fput(ctx->cdev->fp); 2544 kfree(ctx); 2545 } 2546 2547 static int lineinfo_changed_notify(struct notifier_block *nb, 2548 unsigned long action, void *data) 2549 { 2550 struct gpio_chardev_data *cdev = 2551 container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb); 2552 struct lineinfo_changed_ctx *ctx; 2553 struct gpio_desc *desc = data; 2554 2555 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines)) 2556 return NOTIFY_DONE; 2557 2558 /* 2559 * If this is called from atomic context (for instance: with a spinlock 2560 * taken by the atomic notifier chain), any sleeping calls must be done 2561 * outside of this function in process context of the dedicated 2562 * workqueue. 2563 * 2564 * Let's gather as much info as possible from the descriptor and 2565 * postpone just the call to pinctrl_gpio_can_use_line() until the work 2566 * is executed. 2567 */ 2568 2569 ctx = kzalloc(sizeof(*ctx), GFP_ATOMIC); 2570 if (!ctx) { 2571 pr_err("Failed to allocate memory for line info notification\n"); 2572 return NOTIFY_DONE; 2573 } 2574 2575 ctx->chg.event_type = action; 2576 ctx->chg.timestamp_ns = ktime_get_ns(); 2577 gpio_desc_to_lineinfo(desc, &ctx->chg.info, true); 2578 /* Keep the GPIO device alive until we emit the event. */ 2579 ctx->gdev = gpio_device_get(desc->gdev); 2580 ctx->cdev = cdev; 2581 /* Keep the file descriptor alive too. */ 2582 get_file(ctx->cdev->fp); 2583 2584 INIT_WORK(&ctx->work, lineinfo_changed_func); 2585 queue_work(ctx->gdev->line_state_wq, &ctx->work); 2586 2587 return NOTIFY_OK; 2588 } 2589 2590 static int gpio_device_unregistered_notify(struct notifier_block *nb, 2591 unsigned long action, void *data) 2592 { 2593 struct gpio_chardev_data *cdev = container_of(nb, 2594 struct gpio_chardev_data, 2595 device_unregistered_nb); 2596 2597 wake_up_poll(&cdev->wait, EPOLLIN | EPOLLERR); 2598 2599 return NOTIFY_OK; 2600 } 2601 2602 static __poll_t lineinfo_watch_poll(struct file *file, 2603 struct poll_table_struct *pollt) 2604 { 2605 struct gpio_chardev_data *cdev = file->private_data; 2606 __poll_t events = 0; 2607 2608 guard(srcu)(&cdev->gdev->srcu); 2609 2610 if (!rcu_access_pointer(cdev->gdev->chip)) 2611 return EPOLLHUP | EPOLLERR; 2612 2613 poll_wait(file, &cdev->wait, pollt); 2614 2615 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events, 2616 &cdev->wait.lock)) 2617 events = EPOLLIN | EPOLLRDNORM; 2618 2619 return events; 2620 } 2621 2622 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, 2623 size_t count, loff_t *off) 2624 { 2625 struct gpio_chardev_data *cdev = file->private_data; 2626 struct gpio_v2_line_info_changed event; 2627 ssize_t bytes_read = 0; 2628 int ret; 2629 size_t event_size; 2630 2631 guard(srcu)(&cdev->gdev->srcu); 2632 2633 if (!rcu_access_pointer(cdev->gdev->chip)) 2634 return -ENODEV; 2635 2636 #ifndef CONFIG_GPIO_CDEV_V1 2637 event_size = sizeof(struct gpio_v2_line_info_changed); 2638 if (count < event_size) 2639 return -EINVAL; 2640 #endif 2641 2642 do { 2643 scoped_guard(spinlock, &cdev->wait.lock) { 2644 if (kfifo_is_empty(&cdev->events)) { 2645 if (bytes_read) 2646 return bytes_read; 2647 2648 if (file->f_flags & O_NONBLOCK) 2649 return -EAGAIN; 2650 2651 ret = wait_event_interruptible_locked(cdev->wait, 2652 !kfifo_is_empty(&cdev->events)); 2653 if (ret) 2654 return ret; 2655 } 2656 #ifdef CONFIG_GPIO_CDEV_V1 2657 /* must be after kfifo check so watch_abi_version is set */ 2658 if (atomic_read(&cdev->watch_abi_version) == 2) 2659 event_size = sizeof(struct gpio_v2_line_info_changed); 2660 else 2661 event_size = sizeof(struct gpioline_info_changed); 2662 if (count < event_size) 2663 return -EINVAL; 2664 #endif 2665 if (kfifo_out(&cdev->events, &event, 1) != 1) { 2666 /* 2667 * This should never happen - we hold the 2668 * lock from the moment we learned the fifo 2669 * is no longer empty until now. 2670 */ 2671 WARN(1, "failed to read from non-empty kfifo"); 2672 return -EIO; 2673 } 2674 } 2675 2676 #ifdef CONFIG_GPIO_CDEV_V1 2677 if (event_size == sizeof(struct gpio_v2_line_info_changed)) { 2678 if (copy_to_user(buf + bytes_read, &event, event_size)) 2679 return -EFAULT; 2680 } else { 2681 struct gpioline_info_changed event_v1; 2682 2683 gpio_v2_line_info_changed_to_v1(&event, &event_v1); 2684 if (copy_to_user(buf + bytes_read, &event_v1, 2685 event_size)) 2686 return -EFAULT; 2687 } 2688 #else 2689 if (copy_to_user(buf + bytes_read, &event, event_size)) 2690 return -EFAULT; 2691 #endif 2692 bytes_read += event_size; 2693 } while (count >= bytes_read + sizeof(event)); 2694 2695 return bytes_read; 2696 } 2697 2698 /** 2699 * gpio_chrdev_open() - open the chardev for ioctl operations 2700 * @inode: inode for this chardev 2701 * @file: file struct for storing private data 2702 * 2703 * Returns: 2704 * 0 on success, or negative errno on failure. 2705 */ 2706 static int gpio_chrdev_open(struct inode *inode, struct file *file) 2707 { 2708 struct gpio_device *gdev = container_of(inode->i_cdev, 2709 struct gpio_device, chrdev); 2710 struct gpio_chardev_data *cdev; 2711 int ret = -ENOMEM; 2712 2713 guard(srcu)(&gdev->srcu); 2714 2715 /* Fail on open if the backing gpiochip is gone */ 2716 if (!rcu_access_pointer(gdev->chip)) 2717 return -ENODEV; 2718 2719 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL); 2720 if (!cdev) 2721 return -ENODEV; 2722 2723 cdev->watched_lines = bitmap_zalloc(gdev->ngpio, GFP_KERNEL); 2724 if (!cdev->watched_lines) 2725 goto out_free_cdev; 2726 2727 init_waitqueue_head(&cdev->wait); 2728 INIT_KFIFO(cdev->events); 2729 cdev->gdev = gpio_device_get(gdev); 2730 2731 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify; 2732 ret = atomic_notifier_chain_register(&gdev->line_state_notifier, 2733 &cdev->lineinfo_changed_nb); 2734 if (ret) 2735 goto out_free_bitmap; 2736 2737 cdev->device_unregistered_nb.notifier_call = 2738 gpio_device_unregistered_notify; 2739 ret = blocking_notifier_chain_register(&gdev->device_notifier, 2740 &cdev->device_unregistered_nb); 2741 if (ret) 2742 goto out_unregister_line_notifier; 2743 2744 file->private_data = cdev; 2745 cdev->fp = file; 2746 2747 ret = nonseekable_open(inode, file); 2748 if (ret) 2749 goto out_unregister_device_notifier; 2750 2751 return ret; 2752 2753 out_unregister_device_notifier: 2754 blocking_notifier_chain_unregister(&gdev->device_notifier, 2755 &cdev->device_unregistered_nb); 2756 out_unregister_line_notifier: 2757 atomic_notifier_chain_unregister(&gdev->line_state_notifier, 2758 &cdev->lineinfo_changed_nb); 2759 out_free_bitmap: 2760 gpio_device_put(gdev); 2761 bitmap_free(cdev->watched_lines); 2762 out_free_cdev: 2763 kfree(cdev); 2764 return ret; 2765 } 2766 2767 /** 2768 * gpio_chrdev_release() - close chardev after ioctl operations 2769 * @inode: inode for this chardev 2770 * @file: file struct for storing private data 2771 * 2772 * Returns: 2773 * 0 on success, or negative errno on failure. 2774 */ 2775 static int gpio_chrdev_release(struct inode *inode, struct file *file) 2776 { 2777 struct gpio_chardev_data *cdev = file->private_data; 2778 struct gpio_device *gdev = cdev->gdev; 2779 2780 blocking_notifier_chain_unregister(&gdev->device_notifier, 2781 &cdev->device_unregistered_nb); 2782 atomic_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