1 // SPDX-License-Identifier: GPL-2.0 2 3 #include <linux/anon_inodes.h> 4 #include <linux/atomic.h> 5 #include <linux/bitmap.h> 6 #include <linux/build_bug.h> 7 #include <linux/cdev.h> 8 #include <linux/compat.h> 9 #include <linux/compiler.h> 10 #include <linux/device.h> 11 #include <linux/err.h> 12 #include <linux/file.h> 13 #include <linux/gpio.h> 14 #include <linux/gpio/driver.h> 15 #include <linux/hte.h> 16 #include <linux/interrupt.h> 17 #include <linux/irqreturn.h> 18 #include <linux/kernel.h> 19 #include <linux/kfifo.h> 20 #include <linux/module.h> 21 #include <linux/mutex.h> 22 #include <linux/pinctrl/consumer.h> 23 #include <linux/poll.h> 24 #include <linux/seq_file.h> 25 #include <linux/spinlock.h> 26 #include <linux/timekeeping.h> 27 #include <linux/uaccess.h> 28 #include <linux/workqueue.h> 29 30 #include <uapi/linux/gpio.h> 31 32 #include "gpiolib.h" 33 #include "gpiolib-cdev.h" 34 35 /* 36 * Array sizes must ensure 64-bit alignment and not create holes in the 37 * struct packing. 38 */ 39 static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2)); 40 static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8)); 41 42 /* 43 * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility 44 */ 45 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8)); 46 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8)); 47 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8)); 48 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8)); 49 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8)); 50 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8)); 51 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8)); 52 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8)); 53 54 /* Character device interface to GPIO. 55 * 56 * The GPIO character device, /dev/gpiochipN, provides userspace an 57 * interface to gpiolib GPIOs via ioctl()s. 58 */ 59 60 typedef __poll_t (*poll_fn)(struct file *, struct poll_table_struct *); 61 typedef long (*ioctl_fn)(struct file *, unsigned int, unsigned long); 62 typedef ssize_t (*read_fn)(struct file *, char __user *, 63 size_t count, loff_t *); 64 65 static __poll_t call_poll_locked(struct file *file, 66 struct poll_table_struct *wait, 67 struct gpio_device *gdev, poll_fn func) 68 { 69 __poll_t ret; 70 71 down_read(&gdev->sem); 72 ret = func(file, wait); 73 up_read(&gdev->sem); 74 75 return ret; 76 } 77 78 static long call_ioctl_locked(struct file *file, unsigned int cmd, 79 unsigned long arg, struct gpio_device *gdev, 80 ioctl_fn func) 81 { 82 long ret; 83 84 down_read(&gdev->sem); 85 ret = func(file, cmd, arg); 86 up_read(&gdev->sem); 87 88 return ret; 89 } 90 91 static ssize_t call_read_locked(struct file *file, char __user *buf, 92 size_t count, loff_t *f_ps, 93 struct gpio_device *gdev, read_fn func) 94 { 95 ssize_t ret; 96 97 down_read(&gdev->sem); 98 ret = func(file, buf, count, f_ps); 99 up_read(&gdev->sem); 100 101 return ret; 102 } 103 104 /* 105 * GPIO line handle management 106 */ 107 108 #ifdef CONFIG_GPIO_CDEV_V1 109 /** 110 * struct linehandle_state - contains the state of a userspace handle 111 * @gdev: the GPIO device the handle pertains to 112 * @label: consumer label used to tag descriptors 113 * @descs: the GPIO descriptors held by this handle 114 * @num_descs: the number of descriptors held in the descs array 115 */ 116 struct linehandle_state { 117 struct gpio_device *gdev; 118 const char *label; 119 struct gpio_desc *descs[GPIOHANDLES_MAX]; 120 u32 num_descs; 121 }; 122 123 #define GPIOHANDLE_REQUEST_VALID_FLAGS \ 124 (GPIOHANDLE_REQUEST_INPUT | \ 125 GPIOHANDLE_REQUEST_OUTPUT | \ 126 GPIOHANDLE_REQUEST_ACTIVE_LOW | \ 127 GPIOHANDLE_REQUEST_BIAS_PULL_UP | \ 128 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \ 129 GPIOHANDLE_REQUEST_BIAS_DISABLE | \ 130 GPIOHANDLE_REQUEST_OPEN_DRAIN | \ 131 GPIOHANDLE_REQUEST_OPEN_SOURCE) 132 133 static int linehandle_validate_flags(u32 flags) 134 { 135 /* Return an error if an unknown flag is set */ 136 if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) 137 return -EINVAL; 138 139 /* 140 * Do not allow both INPUT & OUTPUT flags to be set as they are 141 * contradictory. 142 */ 143 if ((flags & GPIOHANDLE_REQUEST_INPUT) && 144 (flags & GPIOHANDLE_REQUEST_OUTPUT)) 145 return -EINVAL; 146 147 /* 148 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If 149 * the hardware actually supports enabling both at the same time the 150 * electrical result would be disastrous. 151 */ 152 if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) && 153 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 154 return -EINVAL; 155 156 /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */ 157 if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) && 158 ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 159 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))) 160 return -EINVAL; 161 162 /* Bias flags only allowed for input or output mode. */ 163 if (!((flags & GPIOHANDLE_REQUEST_INPUT) || 164 (flags & GPIOHANDLE_REQUEST_OUTPUT)) && 165 ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) || 166 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) || 167 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN))) 168 return -EINVAL; 169 170 /* Only one bias flag can be set. */ 171 if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 172 (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 173 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 174 ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 175 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 176 return -EINVAL; 177 178 return 0; 179 } 180 181 static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp) 182 { 183 assign_bit(FLAG_ACTIVE_LOW, flagsp, 184 lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW); 185 assign_bit(FLAG_OPEN_DRAIN, flagsp, 186 lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN); 187 assign_bit(FLAG_OPEN_SOURCE, flagsp, 188 lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE); 189 assign_bit(FLAG_PULL_UP, flagsp, 190 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP); 191 assign_bit(FLAG_PULL_DOWN, flagsp, 192 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN); 193 assign_bit(FLAG_BIAS_DISABLE, flagsp, 194 lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE); 195 } 196 197 static long linehandle_set_config(struct linehandle_state *lh, 198 void __user *ip) 199 { 200 struct gpiohandle_config gcnf; 201 struct gpio_desc *desc; 202 int i, ret; 203 u32 lflags; 204 205 if (copy_from_user(&gcnf, ip, sizeof(gcnf))) 206 return -EFAULT; 207 208 lflags = gcnf.flags; 209 ret = linehandle_validate_flags(lflags); 210 if (ret) 211 return ret; 212 213 for (i = 0; i < lh->num_descs; i++) { 214 desc = lh->descs[i]; 215 linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags); 216 217 /* 218 * Lines have to be requested explicitly for input 219 * or output, else the line will be treated "as is". 220 */ 221 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { 222 int val = !!gcnf.default_values[i]; 223 224 ret = gpiod_direction_output(desc, val); 225 if (ret) 226 return ret; 227 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { 228 ret = gpiod_direction_input(desc); 229 if (ret) 230 return ret; 231 } 232 233 blocking_notifier_call_chain(&desc->gdev->notifier, 234 GPIO_V2_LINE_CHANGED_CONFIG, 235 desc); 236 } 237 return 0; 238 } 239 240 static long linehandle_ioctl_unlocked(struct file *file, unsigned int cmd, 241 unsigned long arg) 242 { 243 struct linehandle_state *lh = file->private_data; 244 void __user *ip = (void __user *)arg; 245 struct gpiohandle_data ghd; 246 DECLARE_BITMAP(vals, GPIOHANDLES_MAX); 247 unsigned int i; 248 int ret; 249 250 if (!lh->gdev->chip) 251 return -ENODEV; 252 253 switch (cmd) { 254 case GPIOHANDLE_GET_LINE_VALUES_IOCTL: 255 /* NOTE: It's okay to read values of output lines */ 256 ret = gpiod_get_array_value_complex(false, true, 257 lh->num_descs, lh->descs, 258 NULL, vals); 259 if (ret) 260 return ret; 261 262 memset(&ghd, 0, sizeof(ghd)); 263 for (i = 0; i < lh->num_descs; i++) 264 ghd.values[i] = test_bit(i, vals); 265 266 if (copy_to_user(ip, &ghd, sizeof(ghd))) 267 return -EFAULT; 268 269 return 0; 270 case GPIOHANDLE_SET_LINE_VALUES_IOCTL: 271 /* 272 * All line descriptors were created at once with the same 273 * flags so just check if the first one is really output. 274 */ 275 if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags)) 276 return -EPERM; 277 278 if (copy_from_user(&ghd, ip, sizeof(ghd))) 279 return -EFAULT; 280 281 /* Clamp all values to [0,1] */ 282 for (i = 0; i < lh->num_descs; i++) 283 __assign_bit(i, vals, ghd.values[i]); 284 285 /* Reuse the array setting function */ 286 return gpiod_set_array_value_complex(false, 287 true, 288 lh->num_descs, 289 lh->descs, 290 NULL, 291 vals); 292 case GPIOHANDLE_SET_CONFIG_IOCTL: 293 return linehandle_set_config(lh, ip); 294 default: 295 return -EINVAL; 296 } 297 } 298 299 static long linehandle_ioctl(struct file *file, unsigned int cmd, 300 unsigned long arg) 301 { 302 struct linehandle_state *lh = file->private_data; 303 304 return call_ioctl_locked(file, cmd, arg, lh->gdev, 305 linehandle_ioctl_unlocked); 306 } 307 308 #ifdef CONFIG_COMPAT 309 static long linehandle_ioctl_compat(struct file *file, unsigned int cmd, 310 unsigned long arg) 311 { 312 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 313 } 314 #endif 315 316 static void linehandle_free(struct linehandle_state *lh) 317 { 318 int i; 319 320 for (i = 0; i < lh->num_descs; i++) 321 if (lh->descs[i]) 322 gpiod_free(lh->descs[i]); 323 kfree(lh->label); 324 gpio_device_put(lh->gdev); 325 kfree(lh); 326 } 327 328 static int linehandle_release(struct inode *inode, struct file *file) 329 { 330 linehandle_free(file->private_data); 331 return 0; 332 } 333 334 static const struct file_operations linehandle_fileops = { 335 .release = linehandle_release, 336 .owner = THIS_MODULE, 337 .llseek = noop_llseek, 338 .unlocked_ioctl = linehandle_ioctl, 339 #ifdef CONFIG_COMPAT 340 .compat_ioctl = linehandle_ioctl_compat, 341 #endif 342 }; 343 344 static int linehandle_create(struct gpio_device *gdev, void __user *ip) 345 { 346 struct gpiohandle_request handlereq; 347 struct linehandle_state *lh; 348 struct file *file; 349 int fd, i, ret; 350 u32 lflags; 351 352 if (copy_from_user(&handlereq, ip, sizeof(handlereq))) 353 return -EFAULT; 354 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX)) 355 return -EINVAL; 356 357 lflags = handlereq.flags; 358 359 ret = linehandle_validate_flags(lflags); 360 if (ret) 361 return ret; 362 363 lh = kzalloc(sizeof(*lh), GFP_KERNEL); 364 if (!lh) 365 return -ENOMEM; 366 lh->gdev = gpio_device_get(gdev); 367 368 if (handlereq.consumer_label[0] != '\0') { 369 /* label is only initialized if consumer_label is set */ 370 lh->label = kstrndup(handlereq.consumer_label, 371 sizeof(handlereq.consumer_label) - 1, 372 GFP_KERNEL); 373 if (!lh->label) { 374 ret = -ENOMEM; 375 goto out_free_lh; 376 } 377 } 378 379 lh->num_descs = handlereq.lines; 380 381 /* Request each GPIO */ 382 for (i = 0; i < handlereq.lines; i++) { 383 u32 offset = handlereq.lineoffsets[i]; 384 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset); 385 386 if (IS_ERR(desc)) { 387 ret = PTR_ERR(desc); 388 goto out_free_lh; 389 } 390 391 ret = gpiod_request_user(desc, lh->label); 392 if (ret) 393 goto out_free_lh; 394 lh->descs[i] = desc; 395 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags); 396 397 ret = gpiod_set_transitory(desc, false); 398 if (ret < 0) 399 goto out_free_lh; 400 401 /* 402 * Lines have to be requested explicitly for input 403 * or output, else the line will be treated "as is". 404 */ 405 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { 406 int val = !!handlereq.default_values[i]; 407 408 ret = gpiod_direction_output(desc, val); 409 if (ret) 410 goto out_free_lh; 411 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { 412 ret = gpiod_direction_input(desc); 413 if (ret) 414 goto out_free_lh; 415 } 416 417 blocking_notifier_call_chain(&desc->gdev->notifier, 418 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 419 420 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 421 offset); 422 } 423 424 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 425 if (fd < 0) { 426 ret = fd; 427 goto out_free_lh; 428 } 429 430 file = anon_inode_getfile("gpio-linehandle", 431 &linehandle_fileops, 432 lh, 433 O_RDONLY | O_CLOEXEC); 434 if (IS_ERR(file)) { 435 ret = PTR_ERR(file); 436 goto out_put_unused_fd; 437 } 438 439 handlereq.fd = fd; 440 if (copy_to_user(ip, &handlereq, sizeof(handlereq))) { 441 /* 442 * fput() will trigger the release() callback, so do not go onto 443 * the regular error cleanup path here. 444 */ 445 fput(file); 446 put_unused_fd(fd); 447 return -EFAULT; 448 } 449 450 fd_install(fd, file); 451 452 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 453 lh->num_descs); 454 455 return 0; 456 457 out_put_unused_fd: 458 put_unused_fd(fd); 459 out_free_lh: 460 linehandle_free(lh); 461 return ret; 462 } 463 #endif /* CONFIG_GPIO_CDEV_V1 */ 464 465 /** 466 * struct line - contains the state of a requested line 467 * @desc: the GPIO descriptor for this line. 468 * @req: the corresponding line request 469 * @irq: the interrupt triggered in response to events on this GPIO 470 * @edflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or 471 * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied 472 * @timestamp_ns: cache for the timestamp storing it between hardirq and 473 * IRQ thread, used to bring the timestamp close to the actual event 474 * @req_seqno: the seqno for the current edge event in the sequence of 475 * events for the corresponding line request. This is drawn from the @req. 476 * @line_seqno: the seqno for the current edge event in the sequence of 477 * events for this line. 478 * @work: the worker that implements software debouncing 479 * @sw_debounced: flag indicating if the software debouncer is active 480 * @level: the current debounced physical level of the line 481 * @hdesc: the Hardware Timestamp Engine (HTE) descriptor 482 * @raw_level: the line level at the time of event 483 * @total_discard_seq: the running counter of the discarded events 484 * @last_seqno: the last sequence number before debounce period expires 485 */ 486 struct line { 487 struct gpio_desc *desc; 488 /* 489 * -- edge detector specific fields -- 490 */ 491 struct linereq *req; 492 unsigned int irq; 493 /* 494 * The flags for the active edge detector configuration. 495 * 496 * edflags is set by linereq_create(), linereq_free(), and 497 * linereq_set_config_unlocked(), which are themselves mutually 498 * exclusive, and is accessed by edge_irq_thread(), 499 * process_hw_ts_thread() and debounce_work_func(), 500 * which can all live with a slightly stale value. 501 */ 502 u64 edflags; 503 /* 504 * timestamp_ns and req_seqno are accessed only by 505 * edge_irq_handler() and edge_irq_thread(), which are themselves 506 * mutually exclusive, so no additional protection is necessary. 507 */ 508 u64 timestamp_ns; 509 u32 req_seqno; 510 /* 511 * line_seqno is accessed by either edge_irq_thread() or 512 * debounce_work_func(), which are themselves mutually exclusive, 513 * so no additional protection is necessary. 514 */ 515 u32 line_seqno; 516 /* 517 * -- debouncer specific fields -- 518 */ 519 struct delayed_work work; 520 /* 521 * sw_debounce is accessed by linereq_set_config(), which is the 522 * only setter, and linereq_get_values(), which can live with a 523 * slightly stale value. 524 */ 525 unsigned int sw_debounced; 526 /* 527 * level is accessed by debounce_work_func(), which is the only 528 * setter, and linereq_get_values() which can live with a slightly 529 * stale value. 530 */ 531 unsigned int level; 532 #ifdef CONFIG_HTE 533 struct hte_ts_desc hdesc; 534 /* 535 * HTE provider sets line level at the time of event. The valid 536 * value is 0 or 1 and negative value for an error. 537 */ 538 int raw_level; 539 /* 540 * when sw_debounce is set on HTE enabled line, this is running 541 * counter of the discarded events. 542 */ 543 u32 total_discard_seq; 544 /* 545 * when sw_debounce is set on HTE enabled line, this variable records 546 * last sequence number before debounce period expires. 547 */ 548 u32 last_seqno; 549 #endif /* CONFIG_HTE */ 550 }; 551 552 /** 553 * struct linereq - contains the state of a userspace line request 554 * @gdev: the GPIO device the line request pertains to 555 * @label: consumer label used to tag GPIO descriptors 556 * @num_lines: the number of lines in the lines array 557 * @wait: wait queue that handles blocking reads of events 558 * @event_buffer_size: the number of elements allocated in @events 559 * @events: KFIFO for the GPIO events 560 * @seqno: the sequence number for edge events generated on all lines in 561 * this line request. Note that this is not used when @num_lines is 1, as 562 * the line_seqno is then the same and is cheaper to calculate. 563 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency 564 * of configuration, particularly multi-step accesses to desc flags. 565 * @lines: the lines held by this line request, with @num_lines elements. 566 */ 567 struct linereq { 568 struct gpio_device *gdev; 569 const char *label; 570 u32 num_lines; 571 wait_queue_head_t wait; 572 u32 event_buffer_size; 573 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event); 574 atomic_t seqno; 575 struct mutex config_mutex; 576 struct line lines[]; 577 }; 578 579 #define GPIO_V2_LINE_BIAS_FLAGS \ 580 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \ 581 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \ 582 GPIO_V2_LINE_FLAG_BIAS_DISABLED) 583 584 #define GPIO_V2_LINE_DIRECTION_FLAGS \ 585 (GPIO_V2_LINE_FLAG_INPUT | \ 586 GPIO_V2_LINE_FLAG_OUTPUT) 587 588 #define GPIO_V2_LINE_DRIVE_FLAGS \ 589 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \ 590 GPIO_V2_LINE_FLAG_OPEN_SOURCE) 591 592 #define GPIO_V2_LINE_EDGE_FLAGS \ 593 (GPIO_V2_LINE_FLAG_EDGE_RISING | \ 594 GPIO_V2_LINE_FLAG_EDGE_FALLING) 595 596 #define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS 597 598 #define GPIO_V2_LINE_VALID_FLAGS \ 599 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ 600 GPIO_V2_LINE_DIRECTION_FLAGS | \ 601 GPIO_V2_LINE_DRIVE_FLAGS | \ 602 GPIO_V2_LINE_EDGE_FLAGS | \ 603 GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \ 604 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \ 605 GPIO_V2_LINE_BIAS_FLAGS) 606 607 /* subset of flags relevant for edge detector configuration */ 608 #define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \ 609 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ 610 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \ 611 GPIO_V2_LINE_EDGE_FLAGS) 612 613 static void linereq_put_event(struct linereq *lr, 614 struct gpio_v2_line_event *le) 615 { 616 bool overflow = false; 617 618 spin_lock(&lr->wait.lock); 619 if (kfifo_is_full(&lr->events)) { 620 overflow = true; 621 kfifo_skip(&lr->events); 622 } 623 kfifo_in(&lr->events, le, 1); 624 spin_unlock(&lr->wait.lock); 625 if (!overflow) 626 wake_up_poll(&lr->wait, EPOLLIN); 627 else 628 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 629 } 630 631 static u64 line_event_timestamp(struct line *line) 632 { 633 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags)) 634 return ktime_get_real_ns(); 635 else if (IS_ENABLED(CONFIG_HTE) && 636 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags)) 637 return line->timestamp_ns; 638 639 return ktime_get_ns(); 640 } 641 642 static u32 line_event_id(int level) 643 { 644 return level ? GPIO_V2_LINE_EVENT_RISING_EDGE : 645 GPIO_V2_LINE_EVENT_FALLING_EDGE; 646 } 647 648 #ifdef CONFIG_HTE 649 650 static enum hte_return process_hw_ts_thread(void *p) 651 { 652 struct line *line; 653 struct linereq *lr; 654 struct gpio_v2_line_event le; 655 u64 edflags; 656 int level; 657 658 if (!p) 659 return HTE_CB_HANDLED; 660 661 line = p; 662 lr = line->req; 663 664 memset(&le, 0, sizeof(le)); 665 666 le.timestamp_ns = line->timestamp_ns; 667 edflags = READ_ONCE(line->edflags); 668 669 switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) { 670 case GPIO_V2_LINE_FLAG_EDGE_BOTH: 671 level = (line->raw_level >= 0) ? 672 line->raw_level : 673 gpiod_get_raw_value_cansleep(line->desc); 674 675 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 676 level = !level; 677 678 le.id = line_event_id(level); 679 break; 680 case GPIO_V2_LINE_FLAG_EDGE_RISING: 681 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 682 break; 683 case GPIO_V2_LINE_FLAG_EDGE_FALLING: 684 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 685 break; 686 default: 687 return HTE_CB_HANDLED; 688 } 689 le.line_seqno = line->line_seqno; 690 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno; 691 le.offset = gpio_chip_hwgpio(line->desc); 692 693 linereq_put_event(lr, &le); 694 695 return HTE_CB_HANDLED; 696 } 697 698 static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p) 699 { 700 struct line *line; 701 struct linereq *lr; 702 int diff_seqno = 0; 703 704 if (!ts || !p) 705 return HTE_CB_HANDLED; 706 707 line = p; 708 line->timestamp_ns = ts->tsc; 709 line->raw_level = ts->raw_level; 710 lr = line->req; 711 712 if (READ_ONCE(line->sw_debounced)) { 713 line->total_discard_seq++; 714 line->last_seqno = ts->seq; 715 mod_delayed_work(system_wq, &line->work, 716 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); 717 } else { 718 if (unlikely(ts->seq < line->line_seqno)) 719 return HTE_CB_HANDLED; 720 721 diff_seqno = ts->seq - line->line_seqno; 722 line->line_seqno = ts->seq; 723 if (lr->num_lines != 1) 724 line->req_seqno = atomic_add_return(diff_seqno, 725 &lr->seqno); 726 727 return HTE_RUN_SECOND_CB; 728 } 729 730 return HTE_CB_HANDLED; 731 } 732 733 static int hte_edge_setup(struct line *line, u64 eflags) 734 { 735 int ret; 736 unsigned long flags = 0; 737 struct hte_ts_desc *hdesc = &line->hdesc; 738 739 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING) 740 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 741 HTE_FALLING_EDGE_TS : 742 HTE_RISING_EDGE_TS; 743 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING) 744 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 745 HTE_RISING_EDGE_TS : 746 HTE_FALLING_EDGE_TS; 747 748 line->total_discard_seq = 0; 749 750 hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL, 751 line->desc); 752 753 ret = hte_ts_get(NULL, hdesc, 0); 754 if (ret) 755 return ret; 756 757 return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread, 758 line); 759 } 760 761 #else 762 763 static int hte_edge_setup(struct line *line, u64 eflags) 764 { 765 return 0; 766 } 767 #endif /* CONFIG_HTE */ 768 769 static irqreturn_t edge_irq_thread(int irq, void *p) 770 { 771 struct line *line = p; 772 struct linereq *lr = line->req; 773 struct gpio_v2_line_event le; 774 775 /* Do not leak kernel stack to userspace */ 776 memset(&le, 0, sizeof(le)); 777 778 if (line->timestamp_ns) { 779 le.timestamp_ns = line->timestamp_ns; 780 } else { 781 /* 782 * We may be running from a nested threaded interrupt in 783 * which case we didn't get the timestamp from 784 * edge_irq_handler(). 785 */ 786 le.timestamp_ns = line_event_timestamp(line); 787 if (lr->num_lines != 1) 788 line->req_seqno = atomic_inc_return(&lr->seqno); 789 } 790 line->timestamp_ns = 0; 791 792 switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) { 793 case GPIO_V2_LINE_FLAG_EDGE_BOTH: 794 le.id = line_event_id(gpiod_get_value_cansleep(line->desc)); 795 break; 796 case GPIO_V2_LINE_FLAG_EDGE_RISING: 797 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 798 break; 799 case GPIO_V2_LINE_FLAG_EDGE_FALLING: 800 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 801 break; 802 default: 803 return IRQ_NONE; 804 } 805 line->line_seqno++; 806 le.line_seqno = line->line_seqno; 807 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno; 808 le.offset = gpio_chip_hwgpio(line->desc); 809 810 linereq_put_event(lr, &le); 811 812 return IRQ_HANDLED; 813 } 814 815 static irqreturn_t edge_irq_handler(int irq, void *p) 816 { 817 struct line *line = p; 818 struct linereq *lr = line->req; 819 820 /* 821 * Just store the timestamp in hardirq context so we get it as 822 * close in time as possible to the actual event. 823 */ 824 line->timestamp_ns = line_event_timestamp(line); 825 826 if (lr->num_lines != 1) 827 line->req_seqno = atomic_inc_return(&lr->seqno); 828 829 return IRQ_WAKE_THREAD; 830 } 831 832 /* 833 * returns the current debounced logical value. 834 */ 835 static bool debounced_value(struct line *line) 836 { 837 bool value; 838 839 /* 840 * minor race - debouncer may be stopped here, so edge_detector_stop() 841 * must leave the value unchanged so the following will read the level 842 * from when the debouncer was last running. 843 */ 844 value = READ_ONCE(line->level); 845 846 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags)) 847 value = !value; 848 849 return value; 850 } 851 852 static irqreturn_t debounce_irq_handler(int irq, void *p) 853 { 854 struct line *line = p; 855 856 mod_delayed_work(system_wq, &line->work, 857 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); 858 859 return IRQ_HANDLED; 860 } 861 862 static void debounce_work_func(struct work_struct *work) 863 { 864 struct gpio_v2_line_event le; 865 struct line *line = container_of(work, struct line, work.work); 866 struct linereq *lr; 867 u64 eflags, edflags = READ_ONCE(line->edflags); 868 int level = -1; 869 #ifdef CONFIG_HTE 870 int diff_seqno; 871 872 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) 873 level = line->raw_level; 874 #endif 875 if (level < 0) 876 level = gpiod_get_raw_value_cansleep(line->desc); 877 if (level < 0) { 878 pr_debug_ratelimited("debouncer failed to read line value\n"); 879 return; 880 } 881 882 if (READ_ONCE(line->level) == level) 883 return; 884 885 WRITE_ONCE(line->level, level); 886 887 /* -- edge detection -- */ 888 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS; 889 if (!eflags) 890 return; 891 892 /* switch from physical level to logical - if they differ */ 893 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 894 level = !level; 895 896 /* ignore edges that are not being monitored */ 897 if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) || 898 ((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level)) 899 return; 900 901 /* Do not leak kernel stack to userspace */ 902 memset(&le, 0, sizeof(le)); 903 904 lr = line->req; 905 le.timestamp_ns = line_event_timestamp(line); 906 le.offset = gpio_chip_hwgpio(line->desc); 907 #ifdef CONFIG_HTE 908 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) { 909 /* discard events except the last one */ 910 line->total_discard_seq -= 1; 911 diff_seqno = line->last_seqno - line->total_discard_seq - 912 line->line_seqno; 913 line->line_seqno = line->last_seqno - line->total_discard_seq; 914 le.line_seqno = line->line_seqno; 915 le.seqno = (lr->num_lines == 1) ? 916 le.line_seqno : atomic_add_return(diff_seqno, &lr->seqno); 917 } else 918 #endif /* CONFIG_HTE */ 919 { 920 line->line_seqno++; 921 le.line_seqno = line->line_seqno; 922 le.seqno = (lr->num_lines == 1) ? 923 le.line_seqno : atomic_inc_return(&lr->seqno); 924 } 925 926 le.id = line_event_id(level); 927 928 linereq_put_event(lr, &le); 929 } 930 931 static int debounce_setup(struct line *line, unsigned int debounce_period_us) 932 { 933 unsigned long irqflags; 934 int ret, level, irq; 935 936 /* try hardware */ 937 ret = gpiod_set_debounce(line->desc, debounce_period_us); 938 if (!ret) { 939 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 940 return ret; 941 } 942 if (ret != -ENOTSUPP) 943 return ret; 944 945 if (debounce_period_us) { 946 /* setup software debounce */ 947 level = gpiod_get_raw_value_cansleep(line->desc); 948 if (level < 0) 949 return level; 950 951 if (!(IS_ENABLED(CONFIG_HTE) && 952 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) { 953 irq = gpiod_to_irq(line->desc); 954 if (irq < 0) 955 return -ENXIO; 956 957 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING; 958 ret = request_irq(irq, debounce_irq_handler, irqflags, 959 line->req->label, line); 960 if (ret) 961 return ret; 962 line->irq = irq; 963 } else { 964 ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH); 965 if (ret) 966 return ret; 967 } 968 969 WRITE_ONCE(line->level, level); 970 WRITE_ONCE(line->sw_debounced, 1); 971 } 972 return 0; 973 } 974 975 static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc, 976 unsigned int line_idx) 977 { 978 unsigned int i; 979 u64 mask = BIT_ULL(line_idx); 980 981 for (i = 0; i < lc->num_attrs; i++) { 982 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 983 (lc->attrs[i].mask & mask)) 984 return true; 985 } 986 return false; 987 } 988 989 static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc, 990 unsigned int line_idx) 991 { 992 unsigned int i; 993 u64 mask = BIT_ULL(line_idx); 994 995 for (i = 0; i < lc->num_attrs; i++) { 996 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 997 (lc->attrs[i].mask & mask)) 998 return lc->attrs[i].attr.debounce_period_us; 999 } 1000 return 0; 1001 } 1002 1003 static void edge_detector_stop(struct line *line) 1004 { 1005 if (line->irq) { 1006 free_irq(line->irq, line); 1007 line->irq = 0; 1008 } 1009 1010 #ifdef CONFIG_HTE 1011 if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) 1012 hte_ts_put(&line->hdesc); 1013 #endif 1014 1015 cancel_delayed_work_sync(&line->work); 1016 WRITE_ONCE(line->sw_debounced, 0); 1017 WRITE_ONCE(line->edflags, 0); 1018 if (line->desc) 1019 WRITE_ONCE(line->desc->debounce_period_us, 0); 1020 /* do not change line->level - see comment in debounced_value() */ 1021 } 1022 1023 static int edge_detector_setup(struct line *line, 1024 struct gpio_v2_line_config *lc, 1025 unsigned int line_idx, u64 edflags) 1026 { 1027 u32 debounce_period_us; 1028 unsigned long irqflags = 0; 1029 u64 eflags; 1030 int irq, ret; 1031 1032 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS; 1033 if (eflags && !kfifo_initialized(&line->req->events)) { 1034 ret = kfifo_alloc(&line->req->events, 1035 line->req->event_buffer_size, GFP_KERNEL); 1036 if (ret) 1037 return ret; 1038 } 1039 if (gpio_v2_line_config_debounced(lc, line_idx)) { 1040 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx); 1041 ret = debounce_setup(line, debounce_period_us); 1042 if (ret) 1043 return ret; 1044 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 1045 } 1046 1047 /* detection disabled or sw debouncer will provide edge detection */ 1048 if (!eflags || READ_ONCE(line->sw_debounced)) 1049 return 0; 1050 1051 if (IS_ENABLED(CONFIG_HTE) && 1052 (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1053 return hte_edge_setup(line, edflags); 1054 1055 irq = gpiod_to_irq(line->desc); 1056 if (irq < 0) 1057 return -ENXIO; 1058 1059 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING) 1060 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 1061 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 1062 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING) 1063 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 1064 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 1065 irqflags |= IRQF_ONESHOT; 1066 1067 /* Request a thread to read the events */ 1068 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread, 1069 irqflags, line->req->label, line); 1070 if (ret) 1071 return ret; 1072 1073 line->irq = irq; 1074 return 0; 1075 } 1076 1077 static int edge_detector_update(struct line *line, 1078 struct gpio_v2_line_config *lc, 1079 unsigned int line_idx, u64 edflags) 1080 { 1081 u64 active_edflags = READ_ONCE(line->edflags); 1082 unsigned int debounce_period_us = 1083 gpio_v2_line_config_debounce_period(lc, line_idx); 1084 1085 if ((active_edflags == edflags) && 1086 (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us)) 1087 return 0; 1088 1089 /* sw debounced and still will be...*/ 1090 if (debounce_period_us && READ_ONCE(line->sw_debounced)) { 1091 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 1092 return 0; 1093 } 1094 1095 /* reconfiguring edge detection or sw debounce being disabled */ 1096 if ((line->irq && !READ_ONCE(line->sw_debounced)) || 1097 (active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) || 1098 (!debounce_period_us && READ_ONCE(line->sw_debounced))) 1099 edge_detector_stop(line); 1100 1101 return edge_detector_setup(line, lc, line_idx, edflags); 1102 } 1103 1104 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc, 1105 unsigned int line_idx) 1106 { 1107 unsigned int i; 1108 u64 mask = BIT_ULL(line_idx); 1109 1110 for (i = 0; i < lc->num_attrs; i++) { 1111 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) && 1112 (lc->attrs[i].mask & mask)) 1113 return lc->attrs[i].attr.flags; 1114 } 1115 return lc->flags; 1116 } 1117 1118 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc, 1119 unsigned int line_idx) 1120 { 1121 unsigned int i; 1122 u64 mask = BIT_ULL(line_idx); 1123 1124 for (i = 0; i < lc->num_attrs; i++) { 1125 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) && 1126 (lc->attrs[i].mask & mask)) 1127 return !!(lc->attrs[i].attr.values & mask); 1128 } 1129 return 0; 1130 } 1131 1132 static int gpio_v2_line_flags_validate(u64 flags) 1133 { 1134 /* Return an error if an unknown flag is set */ 1135 if (flags & ~GPIO_V2_LINE_VALID_FLAGS) 1136 return -EINVAL; 1137 1138 if (!IS_ENABLED(CONFIG_HTE) && 1139 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1140 return -EOPNOTSUPP; 1141 1142 /* 1143 * Do not allow both INPUT and OUTPUT flags to be set as they are 1144 * contradictory. 1145 */ 1146 if ((flags & GPIO_V2_LINE_FLAG_INPUT) && 1147 (flags & GPIO_V2_LINE_FLAG_OUTPUT)) 1148 return -EINVAL; 1149 1150 /* Only allow one event clock source */ 1151 if (IS_ENABLED(CONFIG_HTE) && 1152 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME) && 1153 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1154 return -EINVAL; 1155 1156 /* Edge detection requires explicit input. */ 1157 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) && 1158 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 1159 return -EINVAL; 1160 1161 /* 1162 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single 1163 * request. If the hardware actually supports enabling both at the 1164 * same time the electrical result would be disastrous. 1165 */ 1166 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) && 1167 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE)) 1168 return -EINVAL; 1169 1170 /* Drive requires explicit output direction. */ 1171 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) && 1172 !(flags & GPIO_V2_LINE_FLAG_OUTPUT)) 1173 return -EINVAL; 1174 1175 /* Bias requires explicit direction. */ 1176 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) && 1177 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS)) 1178 return -EINVAL; 1179 1180 /* Only one bias flag can be set. */ 1181 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) && 1182 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | 1183 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) || 1184 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) && 1185 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) 1186 return -EINVAL; 1187 1188 return 0; 1189 } 1190 1191 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc, 1192 unsigned int num_lines) 1193 { 1194 unsigned int i; 1195 u64 flags; 1196 int ret; 1197 1198 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX) 1199 return -EINVAL; 1200 1201 if (memchr_inv(lc->padding, 0, sizeof(lc->padding))) 1202 return -EINVAL; 1203 1204 for (i = 0; i < num_lines; i++) { 1205 flags = gpio_v2_line_config_flags(lc, i); 1206 ret = gpio_v2_line_flags_validate(flags); 1207 if (ret) 1208 return ret; 1209 1210 /* debounce requires explicit input */ 1211 if (gpio_v2_line_config_debounced(lc, i) && 1212 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 1213 return -EINVAL; 1214 } 1215 return 0; 1216 } 1217 1218 static void gpio_v2_line_config_flags_to_desc_flags(u64 flags, 1219 unsigned long *flagsp) 1220 { 1221 assign_bit(FLAG_ACTIVE_LOW, flagsp, 1222 flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW); 1223 1224 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) 1225 set_bit(FLAG_IS_OUT, flagsp); 1226 else if (flags & GPIO_V2_LINE_FLAG_INPUT) 1227 clear_bit(FLAG_IS_OUT, flagsp); 1228 1229 assign_bit(FLAG_EDGE_RISING, flagsp, 1230 flags & GPIO_V2_LINE_FLAG_EDGE_RISING); 1231 assign_bit(FLAG_EDGE_FALLING, flagsp, 1232 flags & GPIO_V2_LINE_FLAG_EDGE_FALLING); 1233 1234 assign_bit(FLAG_OPEN_DRAIN, flagsp, 1235 flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN); 1236 assign_bit(FLAG_OPEN_SOURCE, flagsp, 1237 flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE); 1238 1239 assign_bit(FLAG_PULL_UP, flagsp, 1240 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP); 1241 assign_bit(FLAG_PULL_DOWN, flagsp, 1242 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN); 1243 assign_bit(FLAG_BIAS_DISABLE, flagsp, 1244 flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED); 1245 1246 assign_bit(FLAG_EVENT_CLOCK_REALTIME, flagsp, 1247 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME); 1248 assign_bit(FLAG_EVENT_CLOCK_HTE, flagsp, 1249 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE); 1250 } 1251 1252 static long linereq_get_values(struct linereq *lr, void __user *ip) 1253 { 1254 struct gpio_v2_line_values lv; 1255 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1256 struct gpio_desc **descs; 1257 unsigned int i, didx, num_get; 1258 bool val; 1259 int ret; 1260 1261 /* NOTE: It's ok to read values of output lines. */ 1262 if (copy_from_user(&lv, ip, sizeof(lv))) 1263 return -EFAULT; 1264 1265 for (num_get = 0, i = 0; i < lr->num_lines; i++) { 1266 if (lv.mask & BIT_ULL(i)) { 1267 num_get++; 1268 descs = &lr->lines[i].desc; 1269 } 1270 } 1271 1272 if (num_get == 0) 1273 return -EINVAL; 1274 1275 if (num_get != 1) { 1276 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL); 1277 if (!descs) 1278 return -ENOMEM; 1279 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1280 if (lv.mask & BIT_ULL(i)) { 1281 descs[didx] = lr->lines[i].desc; 1282 didx++; 1283 } 1284 } 1285 } 1286 ret = gpiod_get_array_value_complex(false, true, num_get, 1287 descs, NULL, vals); 1288 1289 if (num_get != 1) 1290 kfree(descs); 1291 if (ret) 1292 return ret; 1293 1294 lv.bits = 0; 1295 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1296 if (lv.mask & BIT_ULL(i)) { 1297 if (lr->lines[i].sw_debounced) 1298 val = debounced_value(&lr->lines[i]); 1299 else 1300 val = test_bit(didx, vals); 1301 if (val) 1302 lv.bits |= BIT_ULL(i); 1303 didx++; 1304 } 1305 } 1306 1307 if (copy_to_user(ip, &lv, sizeof(lv))) 1308 return -EFAULT; 1309 1310 return 0; 1311 } 1312 1313 static long linereq_set_values_unlocked(struct linereq *lr, 1314 struct gpio_v2_line_values *lv) 1315 { 1316 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1317 struct gpio_desc **descs; 1318 unsigned int i, didx, num_set; 1319 int ret; 1320 1321 bitmap_zero(vals, GPIO_V2_LINES_MAX); 1322 for (num_set = 0, i = 0; i < lr->num_lines; i++) { 1323 if (lv->mask & BIT_ULL(i)) { 1324 if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags)) 1325 return -EPERM; 1326 if (lv->bits & BIT_ULL(i)) 1327 __set_bit(num_set, vals); 1328 num_set++; 1329 descs = &lr->lines[i].desc; 1330 } 1331 } 1332 if (num_set == 0) 1333 return -EINVAL; 1334 1335 if (num_set != 1) { 1336 /* build compacted desc array and values */ 1337 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL); 1338 if (!descs) 1339 return -ENOMEM; 1340 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1341 if (lv->mask & BIT_ULL(i)) { 1342 descs[didx] = lr->lines[i].desc; 1343 didx++; 1344 } 1345 } 1346 } 1347 ret = gpiod_set_array_value_complex(false, true, num_set, 1348 descs, NULL, vals); 1349 1350 if (num_set != 1) 1351 kfree(descs); 1352 return ret; 1353 } 1354 1355 static long linereq_set_values(struct linereq *lr, void __user *ip) 1356 { 1357 struct gpio_v2_line_values lv; 1358 int ret; 1359 1360 if (copy_from_user(&lv, ip, sizeof(lv))) 1361 return -EFAULT; 1362 1363 mutex_lock(&lr->config_mutex); 1364 1365 ret = linereq_set_values_unlocked(lr, &lv); 1366 1367 mutex_unlock(&lr->config_mutex); 1368 1369 return ret; 1370 } 1371 1372 static long linereq_set_config_unlocked(struct linereq *lr, 1373 struct gpio_v2_line_config *lc) 1374 { 1375 struct gpio_desc *desc; 1376 struct line *line; 1377 unsigned int i; 1378 u64 flags, edflags; 1379 int ret; 1380 1381 for (i = 0; i < lr->num_lines; i++) { 1382 line = &lr->lines[i]; 1383 desc = lr->lines[i].desc; 1384 flags = gpio_v2_line_config_flags(lc, i); 1385 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1386 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS; 1387 /* 1388 * Lines have to be requested explicitly for input 1389 * or output, else the line will be treated "as is". 1390 */ 1391 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1392 int val = gpio_v2_line_config_output_value(lc, i); 1393 1394 edge_detector_stop(line); 1395 ret = gpiod_direction_output(desc, val); 1396 if (ret) 1397 return ret; 1398 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1399 ret = gpiod_direction_input(desc); 1400 if (ret) 1401 return ret; 1402 1403 ret = edge_detector_update(line, lc, i, edflags); 1404 if (ret) 1405 return ret; 1406 } 1407 1408 WRITE_ONCE(line->edflags, edflags); 1409 1410 blocking_notifier_call_chain(&desc->gdev->notifier, 1411 GPIO_V2_LINE_CHANGED_CONFIG, 1412 desc); 1413 } 1414 return 0; 1415 } 1416 1417 static long linereq_set_config(struct linereq *lr, void __user *ip) 1418 { 1419 struct gpio_v2_line_config lc; 1420 int ret; 1421 1422 if (copy_from_user(&lc, ip, sizeof(lc))) 1423 return -EFAULT; 1424 1425 ret = gpio_v2_line_config_validate(&lc, lr->num_lines); 1426 if (ret) 1427 return ret; 1428 1429 mutex_lock(&lr->config_mutex); 1430 1431 ret = linereq_set_config_unlocked(lr, &lc); 1432 1433 mutex_unlock(&lr->config_mutex); 1434 1435 return ret; 1436 } 1437 1438 static long linereq_ioctl_unlocked(struct file *file, unsigned int cmd, 1439 unsigned long arg) 1440 { 1441 struct linereq *lr = file->private_data; 1442 void __user *ip = (void __user *)arg; 1443 1444 if (!lr->gdev->chip) 1445 return -ENODEV; 1446 1447 switch (cmd) { 1448 case GPIO_V2_LINE_GET_VALUES_IOCTL: 1449 return linereq_get_values(lr, ip); 1450 case GPIO_V2_LINE_SET_VALUES_IOCTL: 1451 return linereq_set_values(lr, ip); 1452 case GPIO_V2_LINE_SET_CONFIG_IOCTL: 1453 return linereq_set_config(lr, ip); 1454 default: 1455 return -EINVAL; 1456 } 1457 } 1458 1459 static long linereq_ioctl(struct file *file, unsigned int cmd, 1460 unsigned long arg) 1461 { 1462 struct linereq *lr = file->private_data; 1463 1464 return call_ioctl_locked(file, cmd, arg, lr->gdev, 1465 linereq_ioctl_unlocked); 1466 } 1467 1468 #ifdef CONFIG_COMPAT 1469 static long linereq_ioctl_compat(struct file *file, unsigned int cmd, 1470 unsigned long arg) 1471 { 1472 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1473 } 1474 #endif 1475 1476 static __poll_t linereq_poll_unlocked(struct file *file, 1477 struct poll_table_struct *wait) 1478 { 1479 struct linereq *lr = file->private_data; 1480 __poll_t events = 0; 1481 1482 if (!lr->gdev->chip) 1483 return EPOLLHUP | EPOLLERR; 1484 1485 poll_wait(file, &lr->wait, wait); 1486 1487 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events, 1488 &lr->wait.lock)) 1489 events = EPOLLIN | EPOLLRDNORM; 1490 1491 return events; 1492 } 1493 1494 static __poll_t linereq_poll(struct file *file, 1495 struct poll_table_struct *wait) 1496 { 1497 struct linereq *lr = file->private_data; 1498 1499 return call_poll_locked(file, wait, lr->gdev, linereq_poll_unlocked); 1500 } 1501 1502 static ssize_t linereq_read_unlocked(struct file *file, char __user *buf, 1503 size_t count, loff_t *f_ps) 1504 { 1505 struct linereq *lr = file->private_data; 1506 struct gpio_v2_line_event le; 1507 ssize_t bytes_read = 0; 1508 int ret; 1509 1510 if (!lr->gdev->chip) 1511 return -ENODEV; 1512 1513 if (count < sizeof(le)) 1514 return -EINVAL; 1515 1516 do { 1517 spin_lock(&lr->wait.lock); 1518 if (kfifo_is_empty(&lr->events)) { 1519 if (bytes_read) { 1520 spin_unlock(&lr->wait.lock); 1521 return bytes_read; 1522 } 1523 1524 if (file->f_flags & O_NONBLOCK) { 1525 spin_unlock(&lr->wait.lock); 1526 return -EAGAIN; 1527 } 1528 1529 ret = wait_event_interruptible_locked(lr->wait, 1530 !kfifo_is_empty(&lr->events)); 1531 if (ret) { 1532 spin_unlock(&lr->wait.lock); 1533 return ret; 1534 } 1535 } 1536 1537 ret = kfifo_out(&lr->events, &le, 1); 1538 spin_unlock(&lr->wait.lock); 1539 if (ret != 1) { 1540 /* 1541 * This should never happen - we were holding the 1542 * lock from the moment we learned the fifo is no 1543 * longer empty until now. 1544 */ 1545 ret = -EIO; 1546 break; 1547 } 1548 1549 if (copy_to_user(buf + bytes_read, &le, sizeof(le))) 1550 return -EFAULT; 1551 bytes_read += sizeof(le); 1552 } while (count >= bytes_read + sizeof(le)); 1553 1554 return bytes_read; 1555 } 1556 1557 static ssize_t linereq_read(struct file *file, char __user *buf, 1558 size_t count, loff_t *f_ps) 1559 { 1560 struct linereq *lr = file->private_data; 1561 1562 return call_read_locked(file, buf, count, f_ps, lr->gdev, 1563 linereq_read_unlocked); 1564 } 1565 1566 static void linereq_free(struct linereq *lr) 1567 { 1568 unsigned int i; 1569 1570 for (i = 0; i < lr->num_lines; i++) { 1571 if (lr->lines[i].desc) { 1572 edge_detector_stop(&lr->lines[i]); 1573 gpiod_free(lr->lines[i].desc); 1574 } 1575 } 1576 kfifo_free(&lr->events); 1577 kfree(lr->label); 1578 gpio_device_put(lr->gdev); 1579 kfree(lr); 1580 } 1581 1582 static int linereq_release(struct inode *inode, struct file *file) 1583 { 1584 struct linereq *lr = file->private_data; 1585 1586 linereq_free(lr); 1587 return 0; 1588 } 1589 1590 #ifdef CONFIG_PROC_FS 1591 static void linereq_show_fdinfo(struct seq_file *out, struct file *file) 1592 { 1593 struct linereq *lr = file->private_data; 1594 struct device *dev = &lr->gdev->dev; 1595 u16 i; 1596 1597 seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev)); 1598 1599 for (i = 0; i < lr->num_lines; i++) 1600 seq_printf(out, "gpio-line:\t%d\n", 1601 gpio_chip_hwgpio(lr->lines[i].desc)); 1602 } 1603 #endif 1604 1605 static const struct file_operations line_fileops = { 1606 .release = linereq_release, 1607 .read = linereq_read, 1608 .poll = linereq_poll, 1609 .owner = THIS_MODULE, 1610 .llseek = noop_llseek, 1611 .unlocked_ioctl = linereq_ioctl, 1612 #ifdef CONFIG_COMPAT 1613 .compat_ioctl = linereq_ioctl_compat, 1614 #endif 1615 #ifdef CONFIG_PROC_FS 1616 .show_fdinfo = linereq_show_fdinfo, 1617 #endif 1618 }; 1619 1620 static int linereq_create(struct gpio_device *gdev, void __user *ip) 1621 { 1622 struct gpio_v2_line_request ulr; 1623 struct gpio_v2_line_config *lc; 1624 struct linereq *lr; 1625 struct file *file; 1626 u64 flags, edflags; 1627 unsigned int i; 1628 int fd, ret; 1629 1630 if (copy_from_user(&ulr, ip, sizeof(ulr))) 1631 return -EFAULT; 1632 1633 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX)) 1634 return -EINVAL; 1635 1636 if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding))) 1637 return -EINVAL; 1638 1639 lc = &ulr.config; 1640 ret = gpio_v2_line_config_validate(lc, ulr.num_lines); 1641 if (ret) 1642 return ret; 1643 1644 lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL); 1645 if (!lr) 1646 return -ENOMEM; 1647 1648 lr->gdev = gpio_device_get(gdev); 1649 1650 for (i = 0; i < ulr.num_lines; i++) { 1651 lr->lines[i].req = lr; 1652 WRITE_ONCE(lr->lines[i].sw_debounced, 0); 1653 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func); 1654 } 1655 1656 if (ulr.consumer[0] != '\0') { 1657 /* label is only initialized if consumer is set */ 1658 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1, 1659 GFP_KERNEL); 1660 if (!lr->label) { 1661 ret = -ENOMEM; 1662 goto out_free_linereq; 1663 } 1664 } 1665 1666 mutex_init(&lr->config_mutex); 1667 init_waitqueue_head(&lr->wait); 1668 lr->event_buffer_size = ulr.event_buffer_size; 1669 if (lr->event_buffer_size == 0) 1670 lr->event_buffer_size = ulr.num_lines * 16; 1671 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16) 1672 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16; 1673 1674 atomic_set(&lr->seqno, 0); 1675 lr->num_lines = ulr.num_lines; 1676 1677 /* Request each GPIO */ 1678 for (i = 0; i < ulr.num_lines; i++) { 1679 u32 offset = ulr.offsets[i]; 1680 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset); 1681 1682 if (IS_ERR(desc)) { 1683 ret = PTR_ERR(desc); 1684 goto out_free_linereq; 1685 } 1686 1687 ret = gpiod_request_user(desc, lr->label); 1688 if (ret) 1689 goto out_free_linereq; 1690 1691 lr->lines[i].desc = desc; 1692 flags = gpio_v2_line_config_flags(lc, i); 1693 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1694 1695 ret = gpiod_set_transitory(desc, false); 1696 if (ret < 0) 1697 goto out_free_linereq; 1698 1699 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS; 1700 /* 1701 * Lines have to be requested explicitly for input 1702 * or output, else the line will be treated "as is". 1703 */ 1704 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1705 int val = gpio_v2_line_config_output_value(lc, i); 1706 1707 ret = gpiod_direction_output(desc, val); 1708 if (ret) 1709 goto out_free_linereq; 1710 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1711 ret = gpiod_direction_input(desc); 1712 if (ret) 1713 goto out_free_linereq; 1714 1715 ret = edge_detector_setup(&lr->lines[i], lc, i, 1716 edflags); 1717 if (ret) 1718 goto out_free_linereq; 1719 } 1720 1721 lr->lines[i].edflags = edflags; 1722 1723 blocking_notifier_call_chain(&desc->gdev->notifier, 1724 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 1725 1726 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 1727 offset); 1728 } 1729 1730 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 1731 if (fd < 0) { 1732 ret = fd; 1733 goto out_free_linereq; 1734 } 1735 1736 file = anon_inode_getfile("gpio-line", &line_fileops, lr, 1737 O_RDONLY | O_CLOEXEC); 1738 if (IS_ERR(file)) { 1739 ret = PTR_ERR(file); 1740 goto out_put_unused_fd; 1741 } 1742 1743 ulr.fd = fd; 1744 if (copy_to_user(ip, &ulr, sizeof(ulr))) { 1745 /* 1746 * fput() will trigger the release() callback, so do not go onto 1747 * the regular error cleanup path here. 1748 */ 1749 fput(file); 1750 put_unused_fd(fd); 1751 return -EFAULT; 1752 } 1753 1754 fd_install(fd, file); 1755 1756 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 1757 lr->num_lines); 1758 1759 return 0; 1760 1761 out_put_unused_fd: 1762 put_unused_fd(fd); 1763 out_free_linereq: 1764 linereq_free(lr); 1765 return ret; 1766 } 1767 1768 #ifdef CONFIG_GPIO_CDEV_V1 1769 1770 /* 1771 * GPIO line event management 1772 */ 1773 1774 /** 1775 * struct lineevent_state - contains the state of a userspace event 1776 * @gdev: the GPIO device the event pertains to 1777 * @label: consumer label used to tag descriptors 1778 * @desc: the GPIO descriptor held by this event 1779 * @eflags: the event flags this line was requested with 1780 * @irq: the interrupt that trigger in response to events on this GPIO 1781 * @wait: wait queue that handles blocking reads of 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 DECLARE_KFIFO(events, struct gpioevent_data, 16); 1795 u64 timestamp; 1796 }; 1797 1798 #define GPIOEVENT_REQUEST_VALID_FLAGS \ 1799 (GPIOEVENT_REQUEST_RISING_EDGE | \ 1800 GPIOEVENT_REQUEST_FALLING_EDGE) 1801 1802 static __poll_t lineevent_poll_unlocked(struct file *file, 1803 struct poll_table_struct *wait) 1804 { 1805 struct lineevent_state *le = file->private_data; 1806 __poll_t events = 0; 1807 1808 if (!le->gdev->chip) 1809 return EPOLLHUP | EPOLLERR; 1810 1811 poll_wait(file, &le->wait, wait); 1812 1813 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock)) 1814 events = EPOLLIN | EPOLLRDNORM; 1815 1816 return events; 1817 } 1818 1819 static __poll_t lineevent_poll(struct file *file, 1820 struct poll_table_struct *wait) 1821 { 1822 struct lineevent_state *le = file->private_data; 1823 1824 return call_poll_locked(file, wait, le->gdev, lineevent_poll_unlocked); 1825 } 1826 1827 struct compat_gpioeevent_data { 1828 compat_u64 timestamp; 1829 u32 id; 1830 }; 1831 1832 static ssize_t lineevent_read_unlocked(struct file *file, char __user *buf, 1833 size_t count, loff_t *f_ps) 1834 { 1835 struct lineevent_state *le = file->private_data; 1836 struct gpioevent_data ge; 1837 ssize_t bytes_read = 0; 1838 ssize_t ge_size; 1839 int ret; 1840 1841 if (!le->gdev->chip) 1842 return -ENODEV; 1843 1844 /* 1845 * When compatible system call is being used the struct gpioevent_data, 1846 * in case of at least ia32, has different size due to the alignment 1847 * differences. Because we have first member 64 bits followed by one of 1848 * 32 bits there is no gap between them. The only difference is the 1849 * padding at the end of the data structure. Hence, we calculate the 1850 * actual sizeof() and pass this as an argument to copy_to_user() to 1851 * drop unneeded bytes from the output. 1852 */ 1853 if (compat_need_64bit_alignment_fixup()) 1854 ge_size = sizeof(struct compat_gpioeevent_data); 1855 else 1856 ge_size = sizeof(struct gpioevent_data); 1857 if (count < ge_size) 1858 return -EINVAL; 1859 1860 do { 1861 spin_lock(&le->wait.lock); 1862 if (kfifo_is_empty(&le->events)) { 1863 if (bytes_read) { 1864 spin_unlock(&le->wait.lock); 1865 return bytes_read; 1866 } 1867 1868 if (file->f_flags & O_NONBLOCK) { 1869 spin_unlock(&le->wait.lock); 1870 return -EAGAIN; 1871 } 1872 1873 ret = wait_event_interruptible_locked(le->wait, 1874 !kfifo_is_empty(&le->events)); 1875 if (ret) { 1876 spin_unlock(&le->wait.lock); 1877 return ret; 1878 } 1879 } 1880 1881 ret = kfifo_out(&le->events, &ge, 1); 1882 spin_unlock(&le->wait.lock); 1883 if (ret != 1) { 1884 /* 1885 * This should never happen - we were holding the lock 1886 * from the moment we learned the fifo is no longer 1887 * empty until now. 1888 */ 1889 ret = -EIO; 1890 break; 1891 } 1892 1893 if (copy_to_user(buf + bytes_read, &ge, ge_size)) 1894 return -EFAULT; 1895 bytes_read += ge_size; 1896 } while (count >= bytes_read + ge_size); 1897 1898 return bytes_read; 1899 } 1900 1901 static ssize_t lineevent_read(struct file *file, char __user *buf, 1902 size_t count, loff_t *f_ps) 1903 { 1904 struct lineevent_state *le = file->private_data; 1905 1906 return call_read_locked(file, buf, count, f_ps, le->gdev, 1907 lineevent_read_unlocked); 1908 } 1909 1910 static void lineevent_free(struct lineevent_state *le) 1911 { 1912 if (le->irq) 1913 free_irq(le->irq, le); 1914 if (le->desc) 1915 gpiod_free(le->desc); 1916 kfree(le->label); 1917 gpio_device_put(le->gdev); 1918 kfree(le); 1919 } 1920 1921 static int lineevent_release(struct inode *inode, struct file *file) 1922 { 1923 lineevent_free(file->private_data); 1924 return 0; 1925 } 1926 1927 static long lineevent_ioctl_unlocked(struct file *file, unsigned int cmd, 1928 unsigned long arg) 1929 { 1930 struct lineevent_state *le = file->private_data; 1931 void __user *ip = (void __user *)arg; 1932 struct gpiohandle_data ghd; 1933 1934 if (!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 static long lineevent_ioctl(struct file *file, unsigned int cmd, 1960 unsigned long arg) 1961 { 1962 struct lineevent_state *le = file->private_data; 1963 1964 return call_ioctl_locked(file, cmd, arg, le->gdev, 1965 lineevent_ioctl_unlocked); 1966 } 1967 1968 #ifdef CONFIG_COMPAT 1969 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd, 1970 unsigned long arg) 1971 { 1972 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1973 } 1974 #endif 1975 1976 static const struct file_operations lineevent_fileops = { 1977 .release = lineevent_release, 1978 .read = lineevent_read, 1979 .poll = lineevent_poll, 1980 .owner = THIS_MODULE, 1981 .llseek = noop_llseek, 1982 .unlocked_ioctl = lineevent_ioctl, 1983 #ifdef CONFIG_COMPAT 1984 .compat_ioctl = lineevent_ioctl_compat, 1985 #endif 1986 }; 1987 1988 static irqreturn_t lineevent_irq_thread(int irq, void *p) 1989 { 1990 struct lineevent_state *le = p; 1991 struct gpioevent_data ge; 1992 int ret; 1993 1994 /* Do not leak kernel stack to userspace */ 1995 memset(&ge, 0, sizeof(ge)); 1996 1997 /* 1998 * We may be running from a nested threaded interrupt in which case 1999 * we didn't get the timestamp from lineevent_irq_handler(). 2000 */ 2001 if (!le->timestamp) 2002 ge.timestamp = ktime_get_ns(); 2003 else 2004 ge.timestamp = le->timestamp; 2005 2006 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE 2007 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 2008 int level = gpiod_get_value_cansleep(le->desc); 2009 2010 if (level) 2011 /* Emit low-to-high event */ 2012 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 2013 else 2014 /* Emit high-to-low event */ 2015 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 2016 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) { 2017 /* Emit low-to-high event */ 2018 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 2019 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 2020 /* Emit high-to-low event */ 2021 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 2022 } else { 2023 return IRQ_NONE; 2024 } 2025 2026 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge, 2027 1, &le->wait.lock); 2028 if (ret) 2029 wake_up_poll(&le->wait, EPOLLIN); 2030 else 2031 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 2032 2033 return IRQ_HANDLED; 2034 } 2035 2036 static irqreturn_t lineevent_irq_handler(int irq, void *p) 2037 { 2038 struct lineevent_state *le = p; 2039 2040 /* 2041 * Just store the timestamp in hardirq context so we get it as 2042 * close in time as possible to the actual event. 2043 */ 2044 le->timestamp = ktime_get_ns(); 2045 2046 return IRQ_WAKE_THREAD; 2047 } 2048 2049 static int lineevent_create(struct gpio_device *gdev, void __user *ip) 2050 { 2051 struct gpioevent_request eventreq; 2052 struct lineevent_state *le; 2053 struct gpio_desc *desc; 2054 struct file *file; 2055 u32 offset; 2056 u32 lflags; 2057 u32 eflags; 2058 int fd; 2059 int ret; 2060 int irq, irqflags = 0; 2061 2062 if (copy_from_user(&eventreq, ip, sizeof(eventreq))) 2063 return -EFAULT; 2064 2065 offset = eventreq.lineoffset; 2066 lflags = eventreq.handleflags; 2067 eflags = eventreq.eventflags; 2068 2069 desc = gpiochip_get_desc(gdev->chip, offset); 2070 if (IS_ERR(desc)) 2071 return PTR_ERR(desc); 2072 2073 /* Return an error if a unknown flag is set */ 2074 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) || 2075 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS)) 2076 return -EINVAL; 2077 2078 /* This is just wrong: we don't look for events on output lines */ 2079 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) || 2080 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 2081 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 2082 return -EINVAL; 2083 2084 /* Only one bias flag can be set. */ 2085 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 2086 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 2087 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 2088 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 2089 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 2090 return -EINVAL; 2091 2092 le = kzalloc(sizeof(*le), GFP_KERNEL); 2093 if (!le) 2094 return -ENOMEM; 2095 le->gdev = gpio_device_get(gdev); 2096 2097 if (eventreq.consumer_label[0] != '\0') { 2098 /* label is only initialized if consumer_label is set */ 2099 le->label = kstrndup(eventreq.consumer_label, 2100 sizeof(eventreq.consumer_label) - 1, 2101 GFP_KERNEL); 2102 if (!le->label) { 2103 ret = -ENOMEM; 2104 goto out_free_le; 2105 } 2106 } 2107 2108 ret = gpiod_request_user(desc, le->label); 2109 if (ret) 2110 goto out_free_le; 2111 le->desc = desc; 2112 le->eflags = eflags; 2113 2114 linehandle_flags_to_desc_flags(lflags, &desc->flags); 2115 2116 ret = gpiod_direction_input(desc); 2117 if (ret) 2118 goto out_free_le; 2119 2120 blocking_notifier_call_chain(&desc->gdev->notifier, 2121 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 2122 2123 irq = gpiod_to_irq(desc); 2124 if (irq <= 0) { 2125 ret = -ENODEV; 2126 goto out_free_le; 2127 } 2128 2129 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE) 2130 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 2131 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 2132 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE) 2133 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 2134 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 2135 irqflags |= IRQF_ONESHOT; 2136 2137 INIT_KFIFO(le->events); 2138 init_waitqueue_head(&le->wait); 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 le->label, 2146 le); 2147 if (ret) 2148 goto out_free_le; 2149 2150 le->irq = irq; 2151 2152 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 2153 if (fd < 0) { 2154 ret = fd; 2155 goto out_free_le; 2156 } 2157 2158 file = anon_inode_getfile("gpio-event", 2159 &lineevent_fileops, 2160 le, 2161 O_RDONLY | O_CLOEXEC); 2162 if (IS_ERR(file)) { 2163 ret = PTR_ERR(file); 2164 goto out_put_unused_fd; 2165 } 2166 2167 eventreq.fd = fd; 2168 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) { 2169 /* 2170 * fput() will trigger the release() callback, so do not go onto 2171 * the regular error cleanup path here. 2172 */ 2173 fput(file); 2174 put_unused_fd(fd); 2175 return -EFAULT; 2176 } 2177 2178 fd_install(fd, file); 2179 2180 return 0; 2181 2182 out_put_unused_fd: 2183 put_unused_fd(fd); 2184 out_free_le: 2185 lineevent_free(le); 2186 return ret; 2187 } 2188 2189 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2, 2190 struct gpioline_info *info_v1) 2191 { 2192 u64 flagsv2 = info_v2->flags; 2193 2194 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name)); 2195 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer)); 2196 info_v1->line_offset = info_v2->offset; 2197 info_v1->flags = 0; 2198 2199 if (flagsv2 & GPIO_V2_LINE_FLAG_USED) 2200 info_v1->flags |= GPIOLINE_FLAG_KERNEL; 2201 2202 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT) 2203 info_v1->flags |= GPIOLINE_FLAG_IS_OUT; 2204 2205 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 2206 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW; 2207 2208 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN) 2209 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN; 2210 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE) 2211 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE; 2212 2213 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP) 2214 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP; 2215 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) 2216 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN; 2217 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED) 2218 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE; 2219 } 2220 2221 static void gpio_v2_line_info_changed_to_v1( 2222 struct gpio_v2_line_info_changed *lic_v2, 2223 struct gpioline_info_changed *lic_v1) 2224 { 2225 memset(lic_v1, 0, sizeof(*lic_v1)); 2226 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info); 2227 lic_v1->timestamp = lic_v2->timestamp_ns; 2228 lic_v1->event_type = lic_v2->event_type; 2229 } 2230 2231 #endif /* CONFIG_GPIO_CDEV_V1 */ 2232 2233 static void gpio_desc_to_lineinfo(struct gpio_desc *desc, 2234 struct gpio_v2_line_info *info) 2235 { 2236 struct gpio_chip *gc = desc->gdev->chip; 2237 bool ok_for_pinctrl; 2238 unsigned long flags; 2239 u32 debounce_period_us; 2240 unsigned int num_attrs = 0; 2241 2242 memset(info, 0, sizeof(*info)); 2243 info->offset = gpio_chip_hwgpio(desc); 2244 2245 /* 2246 * This function takes a mutex so we must check this before taking 2247 * the spinlock. 2248 * 2249 * FIXME: find a non-racy way to retrieve this information. Maybe a 2250 * lock common to both frameworks? 2251 */ 2252 ok_for_pinctrl = 2253 pinctrl_gpio_can_use_line(gc->base + info->offset); 2254 2255 spin_lock_irqsave(&gpio_lock, flags); 2256 2257 if (desc->name) 2258 strscpy(info->name, desc->name, sizeof(info->name)); 2259 2260 if (desc->label) 2261 strscpy(info->consumer, desc->label, sizeof(info->consumer)); 2262 2263 /* 2264 * Userspace only need to know that the kernel is using this GPIO so 2265 * it can't use it. 2266 */ 2267 info->flags = 0; 2268 if (test_bit(FLAG_REQUESTED, &desc->flags) || 2269 test_bit(FLAG_IS_HOGGED, &desc->flags) || 2270 test_bit(FLAG_USED_AS_IRQ, &desc->flags) || 2271 test_bit(FLAG_EXPORT, &desc->flags) || 2272 test_bit(FLAG_SYSFS, &desc->flags) || 2273 !gpiochip_line_is_valid(gc, info->offset) || 2274 !ok_for_pinctrl) 2275 info->flags |= GPIO_V2_LINE_FLAG_USED; 2276 2277 if (test_bit(FLAG_IS_OUT, &desc->flags)) 2278 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT; 2279 else 2280 info->flags |= GPIO_V2_LINE_FLAG_INPUT; 2281 2282 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) 2283 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW; 2284 2285 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) 2286 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN; 2287 if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) 2288 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE; 2289 2290 if (test_bit(FLAG_BIAS_DISABLE, &desc->flags)) 2291 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED; 2292 if (test_bit(FLAG_PULL_DOWN, &desc->flags)) 2293 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN; 2294 if (test_bit(FLAG_PULL_UP, &desc->flags)) 2295 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP; 2296 2297 if (test_bit(FLAG_EDGE_RISING, &desc->flags)) 2298 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING; 2299 if (test_bit(FLAG_EDGE_FALLING, &desc->flags)) 2300 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING; 2301 2302 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &desc->flags)) 2303 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME; 2304 else if (test_bit(FLAG_EVENT_CLOCK_HTE, &desc->flags)) 2305 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE; 2306 2307 debounce_period_us = READ_ONCE(desc->debounce_period_us); 2308 if (debounce_period_us) { 2309 info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; 2310 info->attrs[num_attrs].debounce_period_us = debounce_period_us; 2311 num_attrs++; 2312 } 2313 info->num_attrs = num_attrs; 2314 2315 spin_unlock_irqrestore(&gpio_lock, flags); 2316 } 2317 2318 struct gpio_chardev_data { 2319 struct gpio_device *gdev; 2320 wait_queue_head_t wait; 2321 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32); 2322 struct notifier_block lineinfo_changed_nb; 2323 unsigned long *watched_lines; 2324 #ifdef CONFIG_GPIO_CDEV_V1 2325 atomic_t watch_abi_version; 2326 #endif 2327 }; 2328 2329 static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip) 2330 { 2331 struct gpio_device *gdev = cdev->gdev; 2332 struct gpiochip_info chipinfo; 2333 2334 memset(&chipinfo, 0, sizeof(chipinfo)); 2335 2336 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name)); 2337 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label)); 2338 chipinfo.lines = gdev->ngpio; 2339 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo))) 2340 return -EFAULT; 2341 return 0; 2342 } 2343 2344 #ifdef CONFIG_GPIO_CDEV_V1 2345 /* 2346 * returns 0 if the versions match, else the previously selected ABI version 2347 */ 2348 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata, 2349 unsigned int version) 2350 { 2351 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version); 2352 2353 if (abiv == version) 2354 return 0; 2355 2356 return abiv; 2357 } 2358 2359 static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip, 2360 bool watch) 2361 { 2362 struct gpio_desc *desc; 2363 struct gpioline_info lineinfo; 2364 struct gpio_v2_line_info lineinfo_v2; 2365 2366 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2367 return -EFAULT; 2368 2369 /* this doubles as a range check on line_offset */ 2370 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset); 2371 if (IS_ERR(desc)) 2372 return PTR_ERR(desc); 2373 2374 if (watch) { 2375 if (lineinfo_ensure_abi_version(cdev, 1)) 2376 return -EPERM; 2377 2378 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines)) 2379 return -EBUSY; 2380 } 2381 2382 gpio_desc_to_lineinfo(desc, &lineinfo_v2); 2383 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); 2384 2385 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2386 if (watch) 2387 clear_bit(lineinfo.line_offset, cdev->watched_lines); 2388 return -EFAULT; 2389 } 2390 2391 return 0; 2392 } 2393 #endif 2394 2395 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, 2396 bool watch) 2397 { 2398 struct gpio_desc *desc; 2399 struct gpio_v2_line_info lineinfo; 2400 2401 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2402 return -EFAULT; 2403 2404 if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding))) 2405 return -EINVAL; 2406 2407 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset); 2408 if (IS_ERR(desc)) 2409 return PTR_ERR(desc); 2410 2411 if (watch) { 2412 #ifdef CONFIG_GPIO_CDEV_V1 2413 if (lineinfo_ensure_abi_version(cdev, 2)) 2414 return -EPERM; 2415 #endif 2416 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines)) 2417 return -EBUSY; 2418 } 2419 gpio_desc_to_lineinfo(desc, &lineinfo); 2420 2421 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2422 if (watch) 2423 clear_bit(lineinfo.offset, cdev->watched_lines); 2424 return -EFAULT; 2425 } 2426 2427 return 0; 2428 } 2429 2430 static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip) 2431 { 2432 __u32 offset; 2433 2434 if (copy_from_user(&offset, ip, sizeof(offset))) 2435 return -EFAULT; 2436 2437 if (offset >= cdev->gdev->ngpio) 2438 return -EINVAL; 2439 2440 if (!test_and_clear_bit(offset, cdev->watched_lines)) 2441 return -EBUSY; 2442 2443 return 0; 2444 } 2445 2446 /* 2447 * gpio_ioctl() - ioctl handler for the GPIO chardev 2448 */ 2449 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 2450 { 2451 struct gpio_chardev_data *cdev = file->private_data; 2452 struct gpio_device *gdev = cdev->gdev; 2453 void __user *ip = (void __user *)arg; 2454 2455 /* We fail any subsequent ioctl():s when the chip is gone */ 2456 if (!gdev->chip) 2457 return -ENODEV; 2458 2459 /* Fill in the struct and pass to userspace */ 2460 switch (cmd) { 2461 case GPIO_GET_CHIPINFO_IOCTL: 2462 return chipinfo_get(cdev, ip); 2463 #ifdef CONFIG_GPIO_CDEV_V1 2464 case GPIO_GET_LINEHANDLE_IOCTL: 2465 return linehandle_create(gdev, ip); 2466 case GPIO_GET_LINEEVENT_IOCTL: 2467 return lineevent_create(gdev, ip); 2468 case GPIO_GET_LINEINFO_IOCTL: 2469 return lineinfo_get_v1(cdev, ip, false); 2470 case GPIO_GET_LINEINFO_WATCH_IOCTL: 2471 return lineinfo_get_v1(cdev, ip, true); 2472 #endif /* CONFIG_GPIO_CDEV_V1 */ 2473 case GPIO_V2_GET_LINEINFO_IOCTL: 2474 return lineinfo_get(cdev, ip, false); 2475 case GPIO_V2_GET_LINEINFO_WATCH_IOCTL: 2476 return lineinfo_get(cdev, ip, true); 2477 case GPIO_V2_GET_LINE_IOCTL: 2478 return linereq_create(gdev, ip); 2479 case GPIO_GET_LINEINFO_UNWATCH_IOCTL: 2480 return lineinfo_unwatch(cdev, ip); 2481 default: 2482 return -EINVAL; 2483 } 2484 } 2485 2486 #ifdef CONFIG_COMPAT 2487 static long gpio_ioctl_compat(struct file *file, unsigned int cmd, 2488 unsigned long arg) 2489 { 2490 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 2491 } 2492 #endif 2493 2494 static struct gpio_chardev_data * 2495 to_gpio_chardev_data(struct notifier_block *nb) 2496 { 2497 return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb); 2498 } 2499 2500 static int lineinfo_changed_notify(struct notifier_block *nb, 2501 unsigned long action, void *data) 2502 { 2503 struct gpio_chardev_data *cdev = to_gpio_chardev_data(nb); 2504 struct gpio_v2_line_info_changed chg; 2505 struct gpio_desc *desc = data; 2506 int ret; 2507 2508 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines)) 2509 return NOTIFY_DONE; 2510 2511 memset(&chg, 0, sizeof(chg)); 2512 chg.event_type = action; 2513 chg.timestamp_ns = ktime_get_ns(); 2514 gpio_desc_to_lineinfo(desc, &chg.info); 2515 2516 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock); 2517 if (ret) 2518 wake_up_poll(&cdev->wait, EPOLLIN); 2519 else 2520 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n"); 2521 2522 return NOTIFY_OK; 2523 } 2524 2525 static __poll_t lineinfo_watch_poll_unlocked(struct file *file, 2526 struct poll_table_struct *pollt) 2527 { 2528 struct gpio_chardev_data *cdev = file->private_data; 2529 __poll_t events = 0; 2530 2531 if (!cdev->gdev->chip) 2532 return EPOLLHUP | EPOLLERR; 2533 2534 poll_wait(file, &cdev->wait, pollt); 2535 2536 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events, 2537 &cdev->wait.lock)) 2538 events = EPOLLIN | EPOLLRDNORM; 2539 2540 return events; 2541 } 2542 2543 static __poll_t lineinfo_watch_poll(struct file *file, 2544 struct poll_table_struct *pollt) 2545 { 2546 struct gpio_chardev_data *cdev = file->private_data; 2547 2548 return call_poll_locked(file, pollt, cdev->gdev, 2549 lineinfo_watch_poll_unlocked); 2550 } 2551 2552 static ssize_t lineinfo_watch_read_unlocked(struct file *file, char __user *buf, 2553 size_t count, loff_t *off) 2554 { 2555 struct gpio_chardev_data *cdev = file->private_data; 2556 struct gpio_v2_line_info_changed event; 2557 ssize_t bytes_read = 0; 2558 int ret; 2559 size_t event_size; 2560 2561 if (!cdev->gdev->chip) 2562 return -ENODEV; 2563 2564 #ifndef CONFIG_GPIO_CDEV_V1 2565 event_size = sizeof(struct gpio_v2_line_info_changed); 2566 if (count < event_size) 2567 return -EINVAL; 2568 #endif 2569 2570 do { 2571 spin_lock(&cdev->wait.lock); 2572 if (kfifo_is_empty(&cdev->events)) { 2573 if (bytes_read) { 2574 spin_unlock(&cdev->wait.lock); 2575 return bytes_read; 2576 } 2577 2578 if (file->f_flags & O_NONBLOCK) { 2579 spin_unlock(&cdev->wait.lock); 2580 return -EAGAIN; 2581 } 2582 2583 ret = wait_event_interruptible_locked(cdev->wait, 2584 !kfifo_is_empty(&cdev->events)); 2585 if (ret) { 2586 spin_unlock(&cdev->wait.lock); 2587 return ret; 2588 } 2589 } 2590 #ifdef CONFIG_GPIO_CDEV_V1 2591 /* must be after kfifo check so watch_abi_version is set */ 2592 if (atomic_read(&cdev->watch_abi_version) == 2) 2593 event_size = sizeof(struct gpio_v2_line_info_changed); 2594 else 2595 event_size = sizeof(struct gpioline_info_changed); 2596 if (count < event_size) { 2597 spin_unlock(&cdev->wait.lock); 2598 return -EINVAL; 2599 } 2600 #endif 2601 ret = kfifo_out(&cdev->events, &event, 1); 2602 spin_unlock(&cdev->wait.lock); 2603 if (ret != 1) { 2604 ret = -EIO; 2605 break; 2606 /* We should never get here. See lineevent_read(). */ 2607 } 2608 2609 #ifdef CONFIG_GPIO_CDEV_V1 2610 if (event_size == sizeof(struct gpio_v2_line_info_changed)) { 2611 if (copy_to_user(buf + bytes_read, &event, event_size)) 2612 return -EFAULT; 2613 } else { 2614 struct gpioline_info_changed event_v1; 2615 2616 gpio_v2_line_info_changed_to_v1(&event, &event_v1); 2617 if (copy_to_user(buf + bytes_read, &event_v1, 2618 event_size)) 2619 return -EFAULT; 2620 } 2621 #else 2622 if (copy_to_user(buf + bytes_read, &event, event_size)) 2623 return -EFAULT; 2624 #endif 2625 bytes_read += event_size; 2626 } while (count >= bytes_read + sizeof(event)); 2627 2628 return bytes_read; 2629 } 2630 2631 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, 2632 size_t count, loff_t *off) 2633 { 2634 struct gpio_chardev_data *cdev = file->private_data; 2635 2636 return call_read_locked(file, buf, count, off, cdev->gdev, 2637 lineinfo_watch_read_unlocked); 2638 } 2639 2640 /** 2641 * gpio_chrdev_open() - open the chardev for ioctl operations 2642 * @inode: inode for this chardev 2643 * @file: file struct for storing private data 2644 * Returns 0 on success 2645 */ 2646 static int gpio_chrdev_open(struct inode *inode, struct file *file) 2647 { 2648 struct gpio_device *gdev = container_of(inode->i_cdev, 2649 struct gpio_device, chrdev); 2650 struct gpio_chardev_data *cdev; 2651 int ret = -ENOMEM; 2652 2653 down_read(&gdev->sem); 2654 2655 /* Fail on open if the backing gpiochip is gone */ 2656 if (!gdev->chip) { 2657 ret = -ENODEV; 2658 goto out_unlock; 2659 } 2660 2661 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL); 2662 if (!cdev) 2663 goto out_unlock; 2664 2665 cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL); 2666 if (!cdev->watched_lines) 2667 goto out_free_cdev; 2668 2669 init_waitqueue_head(&cdev->wait); 2670 INIT_KFIFO(cdev->events); 2671 cdev->gdev = gpio_device_get(gdev); 2672 2673 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify; 2674 ret = blocking_notifier_chain_register(&gdev->notifier, 2675 &cdev->lineinfo_changed_nb); 2676 if (ret) 2677 goto out_free_bitmap; 2678 2679 file->private_data = cdev; 2680 2681 ret = nonseekable_open(inode, file); 2682 if (ret) 2683 goto out_unregister_notifier; 2684 2685 up_read(&gdev->sem); 2686 2687 return ret; 2688 2689 out_unregister_notifier: 2690 blocking_notifier_chain_unregister(&gdev->notifier, 2691 &cdev->lineinfo_changed_nb); 2692 out_free_bitmap: 2693 gpio_device_put(gdev); 2694 bitmap_free(cdev->watched_lines); 2695 out_free_cdev: 2696 kfree(cdev); 2697 out_unlock: 2698 up_read(&gdev->sem); 2699 return ret; 2700 } 2701 2702 /** 2703 * gpio_chrdev_release() - close chardev after ioctl operations 2704 * @inode: inode for this chardev 2705 * @file: file struct for storing private data 2706 * Returns 0 on success 2707 */ 2708 static int gpio_chrdev_release(struct inode *inode, struct file *file) 2709 { 2710 struct gpio_chardev_data *cdev = file->private_data; 2711 struct gpio_device *gdev = cdev->gdev; 2712 2713 bitmap_free(cdev->watched_lines); 2714 blocking_notifier_chain_unregister(&gdev->notifier, 2715 &cdev->lineinfo_changed_nb); 2716 gpio_device_put(gdev); 2717 kfree(cdev); 2718 2719 return 0; 2720 } 2721 2722 static const struct file_operations gpio_fileops = { 2723 .release = gpio_chrdev_release, 2724 .open = gpio_chrdev_open, 2725 .poll = lineinfo_watch_poll, 2726 .read = lineinfo_watch_read, 2727 .owner = THIS_MODULE, 2728 .llseek = no_llseek, 2729 .unlocked_ioctl = gpio_ioctl, 2730 #ifdef CONFIG_COMPAT 2731 .compat_ioctl = gpio_ioctl_compat, 2732 #endif 2733 }; 2734 2735 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt) 2736 { 2737 int ret; 2738 2739 cdev_init(&gdev->chrdev, &gpio_fileops); 2740 gdev->chrdev.owner = THIS_MODULE; 2741 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id); 2742 2743 ret = cdev_device_add(&gdev->chrdev, &gdev->dev); 2744 if (ret) 2745 return ret; 2746 2747 chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n", 2748 MAJOR(devt), gdev->id); 2749 2750 return 0; 2751 } 2752 2753 void gpiolib_cdev_unregister(struct gpio_device *gdev) 2754 { 2755 cdev_device_del(&gdev->chrdev, &gdev->dev); 2756 } 2757