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->line_state_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->line_state_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 * @device_unregistered_nb: notifier block for receiving gdev unregister events 559 * @event_buffer_size: the number of elements allocated in @events 560 * @events: KFIFO for the GPIO events 561 * @seqno: the sequence number for edge events generated on all lines in 562 * this line request. Note that this is not used when @num_lines is 1, as 563 * the line_seqno is then the same and is cheaper to calculate. 564 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency 565 * of configuration, particularly multi-step accesses to desc flags. 566 * @lines: the lines held by this line request, with @num_lines elements. 567 */ 568 struct linereq { 569 struct gpio_device *gdev; 570 const char *label; 571 u32 num_lines; 572 wait_queue_head_t wait; 573 struct notifier_block device_unregistered_nb; 574 u32 event_buffer_size; 575 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event); 576 atomic_t seqno; 577 struct mutex config_mutex; 578 struct line lines[]; 579 }; 580 581 #define GPIO_V2_LINE_BIAS_FLAGS \ 582 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \ 583 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \ 584 GPIO_V2_LINE_FLAG_BIAS_DISABLED) 585 586 #define GPIO_V2_LINE_DIRECTION_FLAGS \ 587 (GPIO_V2_LINE_FLAG_INPUT | \ 588 GPIO_V2_LINE_FLAG_OUTPUT) 589 590 #define GPIO_V2_LINE_DRIVE_FLAGS \ 591 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \ 592 GPIO_V2_LINE_FLAG_OPEN_SOURCE) 593 594 #define GPIO_V2_LINE_EDGE_FLAGS \ 595 (GPIO_V2_LINE_FLAG_EDGE_RISING | \ 596 GPIO_V2_LINE_FLAG_EDGE_FALLING) 597 598 #define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS 599 600 #define GPIO_V2_LINE_VALID_FLAGS \ 601 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ 602 GPIO_V2_LINE_DIRECTION_FLAGS | \ 603 GPIO_V2_LINE_DRIVE_FLAGS | \ 604 GPIO_V2_LINE_EDGE_FLAGS | \ 605 GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \ 606 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \ 607 GPIO_V2_LINE_BIAS_FLAGS) 608 609 /* subset of flags relevant for edge detector configuration */ 610 #define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \ 611 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ 612 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \ 613 GPIO_V2_LINE_EDGE_FLAGS) 614 615 static int linereq_unregistered_notify(struct notifier_block *nb, 616 unsigned long action, void *data) 617 { 618 struct linereq *lr = container_of(nb, struct linereq, 619 device_unregistered_nb); 620 621 wake_up_poll(&lr->wait, EPOLLIN | EPOLLERR); 622 623 return NOTIFY_OK; 624 } 625 626 static void linereq_put_event(struct linereq *lr, 627 struct gpio_v2_line_event *le) 628 { 629 bool overflow = false; 630 631 spin_lock(&lr->wait.lock); 632 if (kfifo_is_full(&lr->events)) { 633 overflow = true; 634 kfifo_skip(&lr->events); 635 } 636 kfifo_in(&lr->events, le, 1); 637 spin_unlock(&lr->wait.lock); 638 if (!overflow) 639 wake_up_poll(&lr->wait, EPOLLIN); 640 else 641 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 642 } 643 644 static u64 line_event_timestamp(struct line *line) 645 { 646 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags)) 647 return ktime_get_real_ns(); 648 else if (IS_ENABLED(CONFIG_HTE) && 649 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags)) 650 return line->timestamp_ns; 651 652 return ktime_get_ns(); 653 } 654 655 static u32 line_event_id(int level) 656 { 657 return level ? GPIO_V2_LINE_EVENT_RISING_EDGE : 658 GPIO_V2_LINE_EVENT_FALLING_EDGE; 659 } 660 661 #ifdef CONFIG_HTE 662 663 static enum hte_return process_hw_ts_thread(void *p) 664 { 665 struct line *line; 666 struct linereq *lr; 667 struct gpio_v2_line_event le; 668 u64 edflags; 669 int level; 670 671 if (!p) 672 return HTE_CB_HANDLED; 673 674 line = p; 675 lr = line->req; 676 677 memset(&le, 0, sizeof(le)); 678 679 le.timestamp_ns = line->timestamp_ns; 680 edflags = READ_ONCE(line->edflags); 681 682 switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) { 683 case GPIO_V2_LINE_FLAG_EDGE_BOTH: 684 level = (line->raw_level >= 0) ? 685 line->raw_level : 686 gpiod_get_raw_value_cansleep(line->desc); 687 688 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 689 level = !level; 690 691 le.id = line_event_id(level); 692 break; 693 case GPIO_V2_LINE_FLAG_EDGE_RISING: 694 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 695 break; 696 case GPIO_V2_LINE_FLAG_EDGE_FALLING: 697 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 698 break; 699 default: 700 return HTE_CB_HANDLED; 701 } 702 le.line_seqno = line->line_seqno; 703 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno; 704 le.offset = gpio_chip_hwgpio(line->desc); 705 706 linereq_put_event(lr, &le); 707 708 return HTE_CB_HANDLED; 709 } 710 711 static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p) 712 { 713 struct line *line; 714 struct linereq *lr; 715 int diff_seqno = 0; 716 717 if (!ts || !p) 718 return HTE_CB_HANDLED; 719 720 line = p; 721 line->timestamp_ns = ts->tsc; 722 line->raw_level = ts->raw_level; 723 lr = line->req; 724 725 if (READ_ONCE(line->sw_debounced)) { 726 line->total_discard_seq++; 727 line->last_seqno = ts->seq; 728 mod_delayed_work(system_wq, &line->work, 729 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); 730 } else { 731 if (unlikely(ts->seq < line->line_seqno)) 732 return HTE_CB_HANDLED; 733 734 diff_seqno = ts->seq - line->line_seqno; 735 line->line_seqno = ts->seq; 736 if (lr->num_lines != 1) 737 line->req_seqno = atomic_add_return(diff_seqno, 738 &lr->seqno); 739 740 return HTE_RUN_SECOND_CB; 741 } 742 743 return HTE_CB_HANDLED; 744 } 745 746 static int hte_edge_setup(struct line *line, u64 eflags) 747 { 748 int ret; 749 unsigned long flags = 0; 750 struct hte_ts_desc *hdesc = &line->hdesc; 751 752 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING) 753 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 754 HTE_FALLING_EDGE_TS : 755 HTE_RISING_EDGE_TS; 756 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING) 757 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 758 HTE_RISING_EDGE_TS : 759 HTE_FALLING_EDGE_TS; 760 761 line->total_discard_seq = 0; 762 763 hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL, 764 line->desc); 765 766 ret = hte_ts_get(NULL, hdesc, 0); 767 if (ret) 768 return ret; 769 770 return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread, 771 line); 772 } 773 774 #else 775 776 static int hte_edge_setup(struct line *line, u64 eflags) 777 { 778 return 0; 779 } 780 #endif /* CONFIG_HTE */ 781 782 static irqreturn_t edge_irq_thread(int irq, void *p) 783 { 784 struct line *line = p; 785 struct linereq *lr = line->req; 786 struct gpio_v2_line_event le; 787 788 /* Do not leak kernel stack to userspace */ 789 memset(&le, 0, sizeof(le)); 790 791 if (line->timestamp_ns) { 792 le.timestamp_ns = line->timestamp_ns; 793 } else { 794 /* 795 * We may be running from a nested threaded interrupt in 796 * which case we didn't get the timestamp from 797 * edge_irq_handler(). 798 */ 799 le.timestamp_ns = line_event_timestamp(line); 800 if (lr->num_lines != 1) 801 line->req_seqno = atomic_inc_return(&lr->seqno); 802 } 803 line->timestamp_ns = 0; 804 805 switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) { 806 case GPIO_V2_LINE_FLAG_EDGE_BOTH: 807 le.id = line_event_id(gpiod_get_value_cansleep(line->desc)); 808 break; 809 case GPIO_V2_LINE_FLAG_EDGE_RISING: 810 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 811 break; 812 case GPIO_V2_LINE_FLAG_EDGE_FALLING: 813 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 814 break; 815 default: 816 return IRQ_NONE; 817 } 818 line->line_seqno++; 819 le.line_seqno = line->line_seqno; 820 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno; 821 le.offset = gpio_chip_hwgpio(line->desc); 822 823 linereq_put_event(lr, &le); 824 825 return IRQ_HANDLED; 826 } 827 828 static irqreturn_t edge_irq_handler(int irq, void *p) 829 { 830 struct line *line = p; 831 struct linereq *lr = line->req; 832 833 /* 834 * Just store the timestamp in hardirq context so we get it as 835 * close in time as possible to the actual event. 836 */ 837 line->timestamp_ns = line_event_timestamp(line); 838 839 if (lr->num_lines != 1) 840 line->req_seqno = atomic_inc_return(&lr->seqno); 841 842 return IRQ_WAKE_THREAD; 843 } 844 845 /* 846 * returns the current debounced logical value. 847 */ 848 static bool debounced_value(struct line *line) 849 { 850 bool value; 851 852 /* 853 * minor race - debouncer may be stopped here, so edge_detector_stop() 854 * must leave the value unchanged so the following will read the level 855 * from when the debouncer was last running. 856 */ 857 value = READ_ONCE(line->level); 858 859 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags)) 860 value = !value; 861 862 return value; 863 } 864 865 static irqreturn_t debounce_irq_handler(int irq, void *p) 866 { 867 struct line *line = p; 868 869 mod_delayed_work(system_wq, &line->work, 870 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); 871 872 return IRQ_HANDLED; 873 } 874 875 static void debounce_work_func(struct work_struct *work) 876 { 877 struct gpio_v2_line_event le; 878 struct line *line = container_of(work, struct line, work.work); 879 struct linereq *lr; 880 u64 eflags, edflags = READ_ONCE(line->edflags); 881 int level = -1; 882 #ifdef CONFIG_HTE 883 int diff_seqno; 884 885 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) 886 level = line->raw_level; 887 #endif 888 if (level < 0) 889 level = gpiod_get_raw_value_cansleep(line->desc); 890 if (level < 0) { 891 pr_debug_ratelimited("debouncer failed to read line value\n"); 892 return; 893 } 894 895 if (READ_ONCE(line->level) == level) 896 return; 897 898 WRITE_ONCE(line->level, level); 899 900 /* -- edge detection -- */ 901 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS; 902 if (!eflags) 903 return; 904 905 /* switch from physical level to logical - if they differ */ 906 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 907 level = !level; 908 909 /* ignore edges that are not being monitored */ 910 if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) || 911 ((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level)) 912 return; 913 914 /* Do not leak kernel stack to userspace */ 915 memset(&le, 0, sizeof(le)); 916 917 lr = line->req; 918 le.timestamp_ns = line_event_timestamp(line); 919 le.offset = gpio_chip_hwgpio(line->desc); 920 #ifdef CONFIG_HTE 921 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) { 922 /* discard events except the last one */ 923 line->total_discard_seq -= 1; 924 diff_seqno = line->last_seqno - line->total_discard_seq - 925 line->line_seqno; 926 line->line_seqno = line->last_seqno - line->total_discard_seq; 927 le.line_seqno = line->line_seqno; 928 le.seqno = (lr->num_lines == 1) ? 929 le.line_seqno : atomic_add_return(diff_seqno, &lr->seqno); 930 } else 931 #endif /* CONFIG_HTE */ 932 { 933 line->line_seqno++; 934 le.line_seqno = line->line_seqno; 935 le.seqno = (lr->num_lines == 1) ? 936 le.line_seqno : atomic_inc_return(&lr->seqno); 937 } 938 939 le.id = line_event_id(level); 940 941 linereq_put_event(lr, &le); 942 } 943 944 static int debounce_setup(struct line *line, unsigned int debounce_period_us) 945 { 946 unsigned long irqflags; 947 int ret, level, irq; 948 949 /* try hardware */ 950 ret = gpiod_set_debounce(line->desc, debounce_period_us); 951 if (!ret) { 952 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 953 return ret; 954 } 955 if (ret != -ENOTSUPP) 956 return ret; 957 958 if (debounce_period_us) { 959 /* setup software debounce */ 960 level = gpiod_get_raw_value_cansleep(line->desc); 961 if (level < 0) 962 return level; 963 964 if (!(IS_ENABLED(CONFIG_HTE) && 965 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) { 966 irq = gpiod_to_irq(line->desc); 967 if (irq < 0) 968 return -ENXIO; 969 970 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING; 971 ret = request_irq(irq, debounce_irq_handler, irqflags, 972 line->req->label, line); 973 if (ret) 974 return ret; 975 line->irq = irq; 976 } else { 977 ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH); 978 if (ret) 979 return ret; 980 } 981 982 WRITE_ONCE(line->level, level); 983 WRITE_ONCE(line->sw_debounced, 1); 984 } 985 return 0; 986 } 987 988 static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc, 989 unsigned int line_idx) 990 { 991 unsigned int i; 992 u64 mask = BIT_ULL(line_idx); 993 994 for (i = 0; i < lc->num_attrs; i++) { 995 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 996 (lc->attrs[i].mask & mask)) 997 return true; 998 } 999 return false; 1000 } 1001 1002 static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc, 1003 unsigned int line_idx) 1004 { 1005 unsigned int i; 1006 u64 mask = BIT_ULL(line_idx); 1007 1008 for (i = 0; i < lc->num_attrs; i++) { 1009 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 1010 (lc->attrs[i].mask & mask)) 1011 return lc->attrs[i].attr.debounce_period_us; 1012 } 1013 return 0; 1014 } 1015 1016 static void edge_detector_stop(struct line *line) 1017 { 1018 if (line->irq) { 1019 free_irq(line->irq, line); 1020 line->irq = 0; 1021 } 1022 1023 #ifdef CONFIG_HTE 1024 if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) 1025 hte_ts_put(&line->hdesc); 1026 #endif 1027 1028 cancel_delayed_work_sync(&line->work); 1029 WRITE_ONCE(line->sw_debounced, 0); 1030 WRITE_ONCE(line->edflags, 0); 1031 if (line->desc) 1032 WRITE_ONCE(line->desc->debounce_period_us, 0); 1033 /* do not change line->level - see comment in debounced_value() */ 1034 } 1035 1036 static int edge_detector_setup(struct line *line, 1037 struct gpio_v2_line_config *lc, 1038 unsigned int line_idx, u64 edflags) 1039 { 1040 u32 debounce_period_us; 1041 unsigned long irqflags = 0; 1042 u64 eflags; 1043 int irq, ret; 1044 1045 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS; 1046 if (eflags && !kfifo_initialized(&line->req->events)) { 1047 ret = kfifo_alloc(&line->req->events, 1048 line->req->event_buffer_size, GFP_KERNEL); 1049 if (ret) 1050 return ret; 1051 } 1052 if (gpio_v2_line_config_debounced(lc, line_idx)) { 1053 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx); 1054 ret = debounce_setup(line, debounce_period_us); 1055 if (ret) 1056 return ret; 1057 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 1058 } 1059 1060 /* detection disabled or sw debouncer will provide edge detection */ 1061 if (!eflags || READ_ONCE(line->sw_debounced)) 1062 return 0; 1063 1064 if (IS_ENABLED(CONFIG_HTE) && 1065 (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1066 return hte_edge_setup(line, edflags); 1067 1068 irq = gpiod_to_irq(line->desc); 1069 if (irq < 0) 1070 return -ENXIO; 1071 1072 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING) 1073 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 1074 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 1075 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING) 1076 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 1077 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 1078 irqflags |= IRQF_ONESHOT; 1079 1080 /* Request a thread to read the events */ 1081 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread, 1082 irqflags, line->req->label, line); 1083 if (ret) 1084 return ret; 1085 1086 line->irq = irq; 1087 return 0; 1088 } 1089 1090 static int edge_detector_update(struct line *line, 1091 struct gpio_v2_line_config *lc, 1092 unsigned int line_idx, u64 edflags) 1093 { 1094 u64 active_edflags = READ_ONCE(line->edflags); 1095 unsigned int debounce_period_us = 1096 gpio_v2_line_config_debounce_period(lc, line_idx); 1097 1098 if ((active_edflags == edflags) && 1099 (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us)) 1100 return 0; 1101 1102 /* sw debounced and still will be...*/ 1103 if (debounce_period_us && READ_ONCE(line->sw_debounced)) { 1104 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 1105 return 0; 1106 } 1107 1108 /* reconfiguring edge detection or sw debounce being disabled */ 1109 if ((line->irq && !READ_ONCE(line->sw_debounced)) || 1110 (active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) || 1111 (!debounce_period_us && READ_ONCE(line->sw_debounced))) 1112 edge_detector_stop(line); 1113 1114 return edge_detector_setup(line, lc, line_idx, edflags); 1115 } 1116 1117 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc, 1118 unsigned int line_idx) 1119 { 1120 unsigned int i; 1121 u64 mask = BIT_ULL(line_idx); 1122 1123 for (i = 0; i < lc->num_attrs; i++) { 1124 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) && 1125 (lc->attrs[i].mask & mask)) 1126 return lc->attrs[i].attr.flags; 1127 } 1128 return lc->flags; 1129 } 1130 1131 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc, 1132 unsigned int line_idx) 1133 { 1134 unsigned int i; 1135 u64 mask = BIT_ULL(line_idx); 1136 1137 for (i = 0; i < lc->num_attrs; i++) { 1138 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) && 1139 (lc->attrs[i].mask & mask)) 1140 return !!(lc->attrs[i].attr.values & mask); 1141 } 1142 return 0; 1143 } 1144 1145 static int gpio_v2_line_flags_validate(u64 flags) 1146 { 1147 /* Return an error if an unknown flag is set */ 1148 if (flags & ~GPIO_V2_LINE_VALID_FLAGS) 1149 return -EINVAL; 1150 1151 if (!IS_ENABLED(CONFIG_HTE) && 1152 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1153 return -EOPNOTSUPP; 1154 1155 /* 1156 * Do not allow both INPUT and OUTPUT flags to be set as they are 1157 * contradictory. 1158 */ 1159 if ((flags & GPIO_V2_LINE_FLAG_INPUT) && 1160 (flags & GPIO_V2_LINE_FLAG_OUTPUT)) 1161 return -EINVAL; 1162 1163 /* Only allow one event clock source */ 1164 if (IS_ENABLED(CONFIG_HTE) && 1165 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME) && 1166 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1167 return -EINVAL; 1168 1169 /* Edge detection requires explicit input. */ 1170 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) && 1171 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 1172 return -EINVAL; 1173 1174 /* 1175 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single 1176 * request. If the hardware actually supports enabling both at the 1177 * same time the electrical result would be disastrous. 1178 */ 1179 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) && 1180 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE)) 1181 return -EINVAL; 1182 1183 /* Drive requires explicit output direction. */ 1184 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) && 1185 !(flags & GPIO_V2_LINE_FLAG_OUTPUT)) 1186 return -EINVAL; 1187 1188 /* Bias requires explicit direction. */ 1189 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) && 1190 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS)) 1191 return -EINVAL; 1192 1193 /* Only one bias flag can be set. */ 1194 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) && 1195 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | 1196 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) || 1197 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) && 1198 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) 1199 return -EINVAL; 1200 1201 return 0; 1202 } 1203 1204 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc, 1205 unsigned int num_lines) 1206 { 1207 unsigned int i; 1208 u64 flags; 1209 int ret; 1210 1211 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX) 1212 return -EINVAL; 1213 1214 if (memchr_inv(lc->padding, 0, sizeof(lc->padding))) 1215 return -EINVAL; 1216 1217 for (i = 0; i < num_lines; i++) { 1218 flags = gpio_v2_line_config_flags(lc, i); 1219 ret = gpio_v2_line_flags_validate(flags); 1220 if (ret) 1221 return ret; 1222 1223 /* debounce requires explicit input */ 1224 if (gpio_v2_line_config_debounced(lc, i) && 1225 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 1226 return -EINVAL; 1227 } 1228 return 0; 1229 } 1230 1231 static void gpio_v2_line_config_flags_to_desc_flags(u64 flags, 1232 unsigned long *flagsp) 1233 { 1234 assign_bit(FLAG_ACTIVE_LOW, flagsp, 1235 flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW); 1236 1237 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) 1238 set_bit(FLAG_IS_OUT, flagsp); 1239 else if (flags & GPIO_V2_LINE_FLAG_INPUT) 1240 clear_bit(FLAG_IS_OUT, flagsp); 1241 1242 assign_bit(FLAG_EDGE_RISING, flagsp, 1243 flags & GPIO_V2_LINE_FLAG_EDGE_RISING); 1244 assign_bit(FLAG_EDGE_FALLING, flagsp, 1245 flags & GPIO_V2_LINE_FLAG_EDGE_FALLING); 1246 1247 assign_bit(FLAG_OPEN_DRAIN, flagsp, 1248 flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN); 1249 assign_bit(FLAG_OPEN_SOURCE, flagsp, 1250 flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE); 1251 1252 assign_bit(FLAG_PULL_UP, flagsp, 1253 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP); 1254 assign_bit(FLAG_PULL_DOWN, flagsp, 1255 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN); 1256 assign_bit(FLAG_BIAS_DISABLE, flagsp, 1257 flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED); 1258 1259 assign_bit(FLAG_EVENT_CLOCK_REALTIME, flagsp, 1260 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME); 1261 assign_bit(FLAG_EVENT_CLOCK_HTE, flagsp, 1262 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE); 1263 } 1264 1265 static long linereq_get_values(struct linereq *lr, void __user *ip) 1266 { 1267 struct gpio_v2_line_values lv; 1268 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1269 struct gpio_desc **descs; 1270 unsigned int i, didx, num_get; 1271 bool val; 1272 int ret; 1273 1274 /* NOTE: It's ok to read values of output lines. */ 1275 if (copy_from_user(&lv, ip, sizeof(lv))) 1276 return -EFAULT; 1277 1278 for (num_get = 0, i = 0; i < lr->num_lines; i++) { 1279 if (lv.mask & BIT_ULL(i)) { 1280 num_get++; 1281 descs = &lr->lines[i].desc; 1282 } 1283 } 1284 1285 if (num_get == 0) 1286 return -EINVAL; 1287 1288 if (num_get != 1) { 1289 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL); 1290 if (!descs) 1291 return -ENOMEM; 1292 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1293 if (lv.mask & BIT_ULL(i)) { 1294 descs[didx] = lr->lines[i].desc; 1295 didx++; 1296 } 1297 } 1298 } 1299 ret = gpiod_get_array_value_complex(false, true, num_get, 1300 descs, NULL, vals); 1301 1302 if (num_get != 1) 1303 kfree(descs); 1304 if (ret) 1305 return ret; 1306 1307 lv.bits = 0; 1308 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1309 if (lv.mask & BIT_ULL(i)) { 1310 if (lr->lines[i].sw_debounced) 1311 val = debounced_value(&lr->lines[i]); 1312 else 1313 val = test_bit(didx, vals); 1314 if (val) 1315 lv.bits |= BIT_ULL(i); 1316 didx++; 1317 } 1318 } 1319 1320 if (copy_to_user(ip, &lv, sizeof(lv))) 1321 return -EFAULT; 1322 1323 return 0; 1324 } 1325 1326 static long linereq_set_values_unlocked(struct linereq *lr, 1327 struct gpio_v2_line_values *lv) 1328 { 1329 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1330 struct gpio_desc **descs; 1331 unsigned int i, didx, num_set; 1332 int ret; 1333 1334 bitmap_zero(vals, GPIO_V2_LINES_MAX); 1335 for (num_set = 0, i = 0; i < lr->num_lines; i++) { 1336 if (lv->mask & BIT_ULL(i)) { 1337 if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags)) 1338 return -EPERM; 1339 if (lv->bits & BIT_ULL(i)) 1340 __set_bit(num_set, vals); 1341 num_set++; 1342 descs = &lr->lines[i].desc; 1343 } 1344 } 1345 if (num_set == 0) 1346 return -EINVAL; 1347 1348 if (num_set != 1) { 1349 /* build compacted desc array and values */ 1350 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL); 1351 if (!descs) 1352 return -ENOMEM; 1353 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1354 if (lv->mask & BIT_ULL(i)) { 1355 descs[didx] = lr->lines[i].desc; 1356 didx++; 1357 } 1358 } 1359 } 1360 ret = gpiod_set_array_value_complex(false, true, num_set, 1361 descs, NULL, vals); 1362 1363 if (num_set != 1) 1364 kfree(descs); 1365 return ret; 1366 } 1367 1368 static long linereq_set_values(struct linereq *lr, void __user *ip) 1369 { 1370 struct gpio_v2_line_values lv; 1371 int ret; 1372 1373 if (copy_from_user(&lv, ip, sizeof(lv))) 1374 return -EFAULT; 1375 1376 mutex_lock(&lr->config_mutex); 1377 1378 ret = linereq_set_values_unlocked(lr, &lv); 1379 1380 mutex_unlock(&lr->config_mutex); 1381 1382 return ret; 1383 } 1384 1385 static long linereq_set_config_unlocked(struct linereq *lr, 1386 struct gpio_v2_line_config *lc) 1387 { 1388 struct gpio_desc *desc; 1389 struct line *line; 1390 unsigned int i; 1391 u64 flags, edflags; 1392 int ret; 1393 1394 for (i = 0; i < lr->num_lines; i++) { 1395 line = &lr->lines[i]; 1396 desc = lr->lines[i].desc; 1397 flags = gpio_v2_line_config_flags(lc, i); 1398 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1399 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS; 1400 /* 1401 * Lines have to be requested explicitly for input 1402 * or output, else the line will be treated "as is". 1403 */ 1404 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1405 int val = gpio_v2_line_config_output_value(lc, i); 1406 1407 edge_detector_stop(line); 1408 ret = gpiod_direction_output(desc, val); 1409 if (ret) 1410 return ret; 1411 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1412 ret = gpiod_direction_input(desc); 1413 if (ret) 1414 return ret; 1415 1416 ret = edge_detector_update(line, lc, i, edflags); 1417 if (ret) 1418 return ret; 1419 } 1420 1421 WRITE_ONCE(line->edflags, edflags); 1422 1423 blocking_notifier_call_chain(&desc->gdev->line_state_notifier, 1424 GPIO_V2_LINE_CHANGED_CONFIG, 1425 desc); 1426 } 1427 return 0; 1428 } 1429 1430 static long linereq_set_config(struct linereq *lr, void __user *ip) 1431 { 1432 struct gpio_v2_line_config lc; 1433 int ret; 1434 1435 if (copy_from_user(&lc, ip, sizeof(lc))) 1436 return -EFAULT; 1437 1438 ret = gpio_v2_line_config_validate(&lc, lr->num_lines); 1439 if (ret) 1440 return ret; 1441 1442 mutex_lock(&lr->config_mutex); 1443 1444 ret = linereq_set_config_unlocked(lr, &lc); 1445 1446 mutex_unlock(&lr->config_mutex); 1447 1448 return ret; 1449 } 1450 1451 static long linereq_ioctl_unlocked(struct file *file, unsigned int cmd, 1452 unsigned long arg) 1453 { 1454 struct linereq *lr = file->private_data; 1455 void __user *ip = (void __user *)arg; 1456 1457 if (!lr->gdev->chip) 1458 return -ENODEV; 1459 1460 switch (cmd) { 1461 case GPIO_V2_LINE_GET_VALUES_IOCTL: 1462 return linereq_get_values(lr, ip); 1463 case GPIO_V2_LINE_SET_VALUES_IOCTL: 1464 return linereq_set_values(lr, ip); 1465 case GPIO_V2_LINE_SET_CONFIG_IOCTL: 1466 return linereq_set_config(lr, ip); 1467 default: 1468 return -EINVAL; 1469 } 1470 } 1471 1472 static long linereq_ioctl(struct file *file, unsigned int cmd, 1473 unsigned long arg) 1474 { 1475 struct linereq *lr = file->private_data; 1476 1477 return call_ioctl_locked(file, cmd, arg, lr->gdev, 1478 linereq_ioctl_unlocked); 1479 } 1480 1481 #ifdef CONFIG_COMPAT 1482 static long linereq_ioctl_compat(struct file *file, unsigned int cmd, 1483 unsigned long arg) 1484 { 1485 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1486 } 1487 #endif 1488 1489 static __poll_t linereq_poll_unlocked(struct file *file, 1490 struct poll_table_struct *wait) 1491 { 1492 struct linereq *lr = file->private_data; 1493 __poll_t events = 0; 1494 1495 if (!lr->gdev->chip) 1496 return EPOLLHUP | EPOLLERR; 1497 1498 poll_wait(file, &lr->wait, wait); 1499 1500 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events, 1501 &lr->wait.lock)) 1502 events = EPOLLIN | EPOLLRDNORM; 1503 1504 return events; 1505 } 1506 1507 static __poll_t linereq_poll(struct file *file, 1508 struct poll_table_struct *wait) 1509 { 1510 struct linereq *lr = file->private_data; 1511 1512 return call_poll_locked(file, wait, lr->gdev, linereq_poll_unlocked); 1513 } 1514 1515 static ssize_t linereq_read_unlocked(struct file *file, char __user *buf, 1516 size_t count, loff_t *f_ps) 1517 { 1518 struct linereq *lr = file->private_data; 1519 struct gpio_v2_line_event le; 1520 ssize_t bytes_read = 0; 1521 int ret; 1522 1523 if (!lr->gdev->chip) 1524 return -ENODEV; 1525 1526 if (count < sizeof(le)) 1527 return -EINVAL; 1528 1529 do { 1530 spin_lock(&lr->wait.lock); 1531 if (kfifo_is_empty(&lr->events)) { 1532 if (bytes_read) { 1533 spin_unlock(&lr->wait.lock); 1534 return bytes_read; 1535 } 1536 1537 if (file->f_flags & O_NONBLOCK) { 1538 spin_unlock(&lr->wait.lock); 1539 return -EAGAIN; 1540 } 1541 1542 ret = wait_event_interruptible_locked(lr->wait, 1543 !kfifo_is_empty(&lr->events)); 1544 if (ret) { 1545 spin_unlock(&lr->wait.lock); 1546 return ret; 1547 } 1548 } 1549 1550 ret = kfifo_out(&lr->events, &le, 1); 1551 spin_unlock(&lr->wait.lock); 1552 if (ret != 1) { 1553 /* 1554 * This should never happen - we were holding the 1555 * lock from the moment we learned the fifo is no 1556 * longer empty until now. 1557 */ 1558 ret = -EIO; 1559 break; 1560 } 1561 1562 if (copy_to_user(buf + bytes_read, &le, sizeof(le))) 1563 return -EFAULT; 1564 bytes_read += sizeof(le); 1565 } while (count >= bytes_read + sizeof(le)); 1566 1567 return bytes_read; 1568 } 1569 1570 static ssize_t linereq_read(struct file *file, char __user *buf, 1571 size_t count, loff_t *f_ps) 1572 { 1573 struct linereq *lr = file->private_data; 1574 1575 return call_read_locked(file, buf, count, f_ps, lr->gdev, 1576 linereq_read_unlocked); 1577 } 1578 1579 static void linereq_free(struct linereq *lr) 1580 { 1581 unsigned int i; 1582 1583 if (lr->device_unregistered_nb.notifier_call) 1584 blocking_notifier_chain_unregister(&lr->gdev->device_notifier, 1585 &lr->device_unregistered_nb); 1586 1587 for (i = 0; i < lr->num_lines; i++) { 1588 if (lr->lines[i].desc) { 1589 edge_detector_stop(&lr->lines[i]); 1590 gpiod_free(lr->lines[i].desc); 1591 } 1592 } 1593 kfifo_free(&lr->events); 1594 kfree(lr->label); 1595 gpio_device_put(lr->gdev); 1596 kfree(lr); 1597 } 1598 1599 static int linereq_release(struct inode *inode, struct file *file) 1600 { 1601 struct linereq *lr = file->private_data; 1602 1603 linereq_free(lr); 1604 return 0; 1605 } 1606 1607 #ifdef CONFIG_PROC_FS 1608 static void linereq_show_fdinfo(struct seq_file *out, struct file *file) 1609 { 1610 struct linereq *lr = file->private_data; 1611 struct device *dev = &lr->gdev->dev; 1612 u16 i; 1613 1614 seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev)); 1615 1616 for (i = 0; i < lr->num_lines; i++) 1617 seq_printf(out, "gpio-line:\t%d\n", 1618 gpio_chip_hwgpio(lr->lines[i].desc)); 1619 } 1620 #endif 1621 1622 static const struct file_operations line_fileops = { 1623 .release = linereq_release, 1624 .read = linereq_read, 1625 .poll = linereq_poll, 1626 .owner = THIS_MODULE, 1627 .llseek = noop_llseek, 1628 .unlocked_ioctl = linereq_ioctl, 1629 #ifdef CONFIG_COMPAT 1630 .compat_ioctl = linereq_ioctl_compat, 1631 #endif 1632 #ifdef CONFIG_PROC_FS 1633 .show_fdinfo = linereq_show_fdinfo, 1634 #endif 1635 }; 1636 1637 static int linereq_create(struct gpio_device *gdev, void __user *ip) 1638 { 1639 struct gpio_v2_line_request ulr; 1640 struct gpio_v2_line_config *lc; 1641 struct linereq *lr; 1642 struct file *file; 1643 u64 flags, edflags; 1644 unsigned int i; 1645 int fd, ret; 1646 1647 if (copy_from_user(&ulr, ip, sizeof(ulr))) 1648 return -EFAULT; 1649 1650 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX)) 1651 return -EINVAL; 1652 1653 if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding))) 1654 return -EINVAL; 1655 1656 lc = &ulr.config; 1657 ret = gpio_v2_line_config_validate(lc, ulr.num_lines); 1658 if (ret) 1659 return ret; 1660 1661 lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL); 1662 if (!lr) 1663 return -ENOMEM; 1664 1665 lr->gdev = gpio_device_get(gdev); 1666 1667 for (i = 0; i < ulr.num_lines; i++) { 1668 lr->lines[i].req = lr; 1669 WRITE_ONCE(lr->lines[i].sw_debounced, 0); 1670 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func); 1671 } 1672 1673 if (ulr.consumer[0] != '\0') { 1674 /* label is only initialized if consumer is set */ 1675 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1, 1676 GFP_KERNEL); 1677 if (!lr->label) { 1678 ret = -ENOMEM; 1679 goto out_free_linereq; 1680 } 1681 } 1682 1683 mutex_init(&lr->config_mutex); 1684 init_waitqueue_head(&lr->wait); 1685 lr->event_buffer_size = ulr.event_buffer_size; 1686 if (lr->event_buffer_size == 0) 1687 lr->event_buffer_size = ulr.num_lines * 16; 1688 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16) 1689 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16; 1690 1691 atomic_set(&lr->seqno, 0); 1692 lr->num_lines = ulr.num_lines; 1693 1694 /* Request each GPIO */ 1695 for (i = 0; i < ulr.num_lines; i++) { 1696 u32 offset = ulr.offsets[i]; 1697 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset); 1698 1699 if (IS_ERR(desc)) { 1700 ret = PTR_ERR(desc); 1701 goto out_free_linereq; 1702 } 1703 1704 ret = gpiod_request_user(desc, lr->label); 1705 if (ret) 1706 goto out_free_linereq; 1707 1708 lr->lines[i].desc = desc; 1709 flags = gpio_v2_line_config_flags(lc, i); 1710 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1711 1712 ret = gpiod_set_transitory(desc, false); 1713 if (ret < 0) 1714 goto out_free_linereq; 1715 1716 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS; 1717 /* 1718 * Lines have to be requested explicitly for input 1719 * or output, else the line will be treated "as is". 1720 */ 1721 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1722 int val = gpio_v2_line_config_output_value(lc, i); 1723 1724 ret = gpiod_direction_output(desc, val); 1725 if (ret) 1726 goto out_free_linereq; 1727 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1728 ret = gpiod_direction_input(desc); 1729 if (ret) 1730 goto out_free_linereq; 1731 1732 ret = edge_detector_setup(&lr->lines[i], lc, i, 1733 edflags); 1734 if (ret) 1735 goto out_free_linereq; 1736 } 1737 1738 lr->lines[i].edflags = edflags; 1739 1740 blocking_notifier_call_chain(&desc->gdev->line_state_notifier, 1741 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 1742 1743 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 1744 offset); 1745 } 1746 1747 lr->device_unregistered_nb.notifier_call = linereq_unregistered_notify; 1748 ret = blocking_notifier_chain_register(&gdev->device_notifier, 1749 &lr->device_unregistered_nb); 1750 if (ret) 1751 goto out_free_linereq; 1752 1753 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 1754 if (fd < 0) { 1755 ret = fd; 1756 goto out_free_linereq; 1757 } 1758 1759 file = anon_inode_getfile("gpio-line", &line_fileops, lr, 1760 O_RDONLY | O_CLOEXEC); 1761 if (IS_ERR(file)) { 1762 ret = PTR_ERR(file); 1763 goto out_put_unused_fd; 1764 } 1765 1766 ulr.fd = fd; 1767 if (copy_to_user(ip, &ulr, sizeof(ulr))) { 1768 /* 1769 * fput() will trigger the release() callback, so do not go onto 1770 * the regular error cleanup path here. 1771 */ 1772 fput(file); 1773 put_unused_fd(fd); 1774 return -EFAULT; 1775 } 1776 1777 fd_install(fd, file); 1778 1779 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 1780 lr->num_lines); 1781 1782 return 0; 1783 1784 out_put_unused_fd: 1785 put_unused_fd(fd); 1786 out_free_linereq: 1787 linereq_free(lr); 1788 return ret; 1789 } 1790 1791 #ifdef CONFIG_GPIO_CDEV_V1 1792 1793 /* 1794 * GPIO line event management 1795 */ 1796 1797 /** 1798 * struct lineevent_state - contains the state of a userspace event 1799 * @gdev: the GPIO device the event pertains to 1800 * @label: consumer label used to tag descriptors 1801 * @desc: the GPIO descriptor held by this event 1802 * @eflags: the event flags this line was requested with 1803 * @irq: the interrupt that trigger in response to events on this GPIO 1804 * @wait: wait queue that handles blocking reads of events 1805 * @device_unregistered_nb: notifier block for receiving gdev unregister events 1806 * @events: KFIFO for the GPIO events 1807 * @timestamp: cache for the timestamp storing it between hardirq 1808 * and IRQ thread, used to bring the timestamp close to the actual 1809 * event 1810 */ 1811 struct lineevent_state { 1812 struct gpio_device *gdev; 1813 const char *label; 1814 struct gpio_desc *desc; 1815 u32 eflags; 1816 int irq; 1817 wait_queue_head_t wait; 1818 struct notifier_block device_unregistered_nb; 1819 DECLARE_KFIFO(events, struct gpioevent_data, 16); 1820 u64 timestamp; 1821 }; 1822 1823 #define GPIOEVENT_REQUEST_VALID_FLAGS \ 1824 (GPIOEVENT_REQUEST_RISING_EDGE | \ 1825 GPIOEVENT_REQUEST_FALLING_EDGE) 1826 1827 static __poll_t lineevent_poll_unlocked(struct file *file, 1828 struct poll_table_struct *wait) 1829 { 1830 struct lineevent_state *le = file->private_data; 1831 __poll_t events = 0; 1832 1833 if (!le->gdev->chip) 1834 return EPOLLHUP | EPOLLERR; 1835 1836 poll_wait(file, &le->wait, wait); 1837 1838 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock)) 1839 events = EPOLLIN | EPOLLRDNORM; 1840 1841 return events; 1842 } 1843 1844 static __poll_t lineevent_poll(struct file *file, 1845 struct poll_table_struct *wait) 1846 { 1847 struct lineevent_state *le = file->private_data; 1848 1849 return call_poll_locked(file, wait, le->gdev, lineevent_poll_unlocked); 1850 } 1851 1852 static int lineevent_unregistered_notify(struct notifier_block *nb, 1853 unsigned long action, void *data) 1854 { 1855 struct lineevent_state *le = container_of(nb, struct lineevent_state, 1856 device_unregistered_nb); 1857 1858 wake_up_poll(&le->wait, EPOLLIN | EPOLLERR); 1859 1860 return NOTIFY_OK; 1861 } 1862 1863 struct compat_gpioeevent_data { 1864 compat_u64 timestamp; 1865 u32 id; 1866 }; 1867 1868 static ssize_t lineevent_read_unlocked(struct file *file, char __user *buf, 1869 size_t count, loff_t *f_ps) 1870 { 1871 struct lineevent_state *le = file->private_data; 1872 struct gpioevent_data ge; 1873 ssize_t bytes_read = 0; 1874 ssize_t ge_size; 1875 int ret; 1876 1877 if (!le->gdev->chip) 1878 return -ENODEV; 1879 1880 /* 1881 * When compatible system call is being used the struct gpioevent_data, 1882 * in case of at least ia32, has different size due to the alignment 1883 * differences. Because we have first member 64 bits followed by one of 1884 * 32 bits there is no gap between them. The only difference is the 1885 * padding at the end of the data structure. Hence, we calculate the 1886 * actual sizeof() and pass this as an argument to copy_to_user() to 1887 * drop unneeded bytes from the output. 1888 */ 1889 if (compat_need_64bit_alignment_fixup()) 1890 ge_size = sizeof(struct compat_gpioeevent_data); 1891 else 1892 ge_size = sizeof(struct gpioevent_data); 1893 if (count < ge_size) 1894 return -EINVAL; 1895 1896 do { 1897 spin_lock(&le->wait.lock); 1898 if (kfifo_is_empty(&le->events)) { 1899 if (bytes_read) { 1900 spin_unlock(&le->wait.lock); 1901 return bytes_read; 1902 } 1903 1904 if (file->f_flags & O_NONBLOCK) { 1905 spin_unlock(&le->wait.lock); 1906 return -EAGAIN; 1907 } 1908 1909 ret = wait_event_interruptible_locked(le->wait, 1910 !kfifo_is_empty(&le->events)); 1911 if (ret) { 1912 spin_unlock(&le->wait.lock); 1913 return ret; 1914 } 1915 } 1916 1917 ret = kfifo_out(&le->events, &ge, 1); 1918 spin_unlock(&le->wait.lock); 1919 if (ret != 1) { 1920 /* 1921 * This should never happen - we were holding the lock 1922 * from the moment we learned the fifo is no longer 1923 * empty until now. 1924 */ 1925 ret = -EIO; 1926 break; 1927 } 1928 1929 if (copy_to_user(buf + bytes_read, &ge, ge_size)) 1930 return -EFAULT; 1931 bytes_read += ge_size; 1932 } while (count >= bytes_read + ge_size); 1933 1934 return bytes_read; 1935 } 1936 1937 static ssize_t lineevent_read(struct file *file, char __user *buf, 1938 size_t count, loff_t *f_ps) 1939 { 1940 struct lineevent_state *le = file->private_data; 1941 1942 return call_read_locked(file, buf, count, f_ps, le->gdev, 1943 lineevent_read_unlocked); 1944 } 1945 1946 static void lineevent_free(struct lineevent_state *le) 1947 { 1948 if (le->device_unregistered_nb.notifier_call) 1949 blocking_notifier_chain_unregister(&le->gdev->device_notifier, 1950 &le->device_unregistered_nb); 1951 if (le->irq) 1952 free_irq(le->irq, le); 1953 if (le->desc) 1954 gpiod_free(le->desc); 1955 kfree(le->label); 1956 gpio_device_put(le->gdev); 1957 kfree(le); 1958 } 1959 1960 static int lineevent_release(struct inode *inode, struct file *file) 1961 { 1962 lineevent_free(file->private_data); 1963 return 0; 1964 } 1965 1966 static long lineevent_ioctl_unlocked(struct file *file, unsigned int cmd, 1967 unsigned long arg) 1968 { 1969 struct lineevent_state *le = file->private_data; 1970 void __user *ip = (void __user *)arg; 1971 struct gpiohandle_data ghd; 1972 1973 if (!le->gdev->chip) 1974 return -ENODEV; 1975 1976 /* 1977 * We can get the value for an event line but not set it, 1978 * because it is input by definition. 1979 */ 1980 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { 1981 int val; 1982 1983 memset(&ghd, 0, sizeof(ghd)); 1984 1985 val = gpiod_get_value_cansleep(le->desc); 1986 if (val < 0) 1987 return val; 1988 ghd.values[0] = val; 1989 1990 if (copy_to_user(ip, &ghd, sizeof(ghd))) 1991 return -EFAULT; 1992 1993 return 0; 1994 } 1995 return -EINVAL; 1996 } 1997 1998 static long lineevent_ioctl(struct file *file, unsigned int cmd, 1999 unsigned long arg) 2000 { 2001 struct lineevent_state *le = file->private_data; 2002 2003 return call_ioctl_locked(file, cmd, arg, le->gdev, 2004 lineevent_ioctl_unlocked); 2005 } 2006 2007 #ifdef CONFIG_COMPAT 2008 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd, 2009 unsigned long arg) 2010 { 2011 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 2012 } 2013 #endif 2014 2015 static const struct file_operations lineevent_fileops = { 2016 .release = lineevent_release, 2017 .read = lineevent_read, 2018 .poll = lineevent_poll, 2019 .owner = THIS_MODULE, 2020 .llseek = noop_llseek, 2021 .unlocked_ioctl = lineevent_ioctl, 2022 #ifdef CONFIG_COMPAT 2023 .compat_ioctl = lineevent_ioctl_compat, 2024 #endif 2025 }; 2026 2027 static irqreturn_t lineevent_irq_thread(int irq, void *p) 2028 { 2029 struct lineevent_state *le = p; 2030 struct gpioevent_data ge; 2031 int ret; 2032 2033 /* Do not leak kernel stack to userspace */ 2034 memset(&ge, 0, sizeof(ge)); 2035 2036 /* 2037 * We may be running from a nested threaded interrupt in which case 2038 * we didn't get the timestamp from lineevent_irq_handler(). 2039 */ 2040 if (!le->timestamp) 2041 ge.timestamp = ktime_get_ns(); 2042 else 2043 ge.timestamp = le->timestamp; 2044 2045 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE 2046 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 2047 int level = gpiod_get_value_cansleep(le->desc); 2048 2049 if (level) 2050 /* Emit low-to-high event */ 2051 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 2052 else 2053 /* Emit high-to-low event */ 2054 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 2055 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) { 2056 /* Emit low-to-high event */ 2057 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 2058 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 2059 /* Emit high-to-low event */ 2060 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 2061 } else { 2062 return IRQ_NONE; 2063 } 2064 2065 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge, 2066 1, &le->wait.lock); 2067 if (ret) 2068 wake_up_poll(&le->wait, EPOLLIN); 2069 else 2070 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 2071 2072 return IRQ_HANDLED; 2073 } 2074 2075 static irqreturn_t lineevent_irq_handler(int irq, void *p) 2076 { 2077 struct lineevent_state *le = p; 2078 2079 /* 2080 * Just store the timestamp in hardirq context so we get it as 2081 * close in time as possible to the actual event. 2082 */ 2083 le->timestamp = ktime_get_ns(); 2084 2085 return IRQ_WAKE_THREAD; 2086 } 2087 2088 static int lineevent_create(struct gpio_device *gdev, void __user *ip) 2089 { 2090 struct gpioevent_request eventreq; 2091 struct lineevent_state *le; 2092 struct gpio_desc *desc; 2093 struct file *file; 2094 u32 offset; 2095 u32 lflags; 2096 u32 eflags; 2097 int fd; 2098 int ret; 2099 int irq, irqflags = 0; 2100 2101 if (copy_from_user(&eventreq, ip, sizeof(eventreq))) 2102 return -EFAULT; 2103 2104 offset = eventreq.lineoffset; 2105 lflags = eventreq.handleflags; 2106 eflags = eventreq.eventflags; 2107 2108 desc = gpiochip_get_desc(gdev->chip, offset); 2109 if (IS_ERR(desc)) 2110 return PTR_ERR(desc); 2111 2112 /* Return an error if a unknown flag is set */ 2113 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) || 2114 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS)) 2115 return -EINVAL; 2116 2117 /* This is just wrong: we don't look for events on output lines */ 2118 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) || 2119 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 2120 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 2121 return -EINVAL; 2122 2123 /* Only one bias flag can be set. */ 2124 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 2125 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 2126 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 2127 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 2128 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 2129 return -EINVAL; 2130 2131 le = kzalloc(sizeof(*le), GFP_KERNEL); 2132 if (!le) 2133 return -ENOMEM; 2134 le->gdev = gpio_device_get(gdev); 2135 2136 if (eventreq.consumer_label[0] != '\0') { 2137 /* label is only initialized if consumer_label is set */ 2138 le->label = kstrndup(eventreq.consumer_label, 2139 sizeof(eventreq.consumer_label) - 1, 2140 GFP_KERNEL); 2141 if (!le->label) { 2142 ret = -ENOMEM; 2143 goto out_free_le; 2144 } 2145 } 2146 2147 ret = gpiod_request_user(desc, le->label); 2148 if (ret) 2149 goto out_free_le; 2150 le->desc = desc; 2151 le->eflags = eflags; 2152 2153 linehandle_flags_to_desc_flags(lflags, &desc->flags); 2154 2155 ret = gpiod_direction_input(desc); 2156 if (ret) 2157 goto out_free_le; 2158 2159 blocking_notifier_call_chain(&desc->gdev->line_state_notifier, 2160 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 2161 2162 irq = gpiod_to_irq(desc); 2163 if (irq <= 0) { 2164 ret = -ENODEV; 2165 goto out_free_le; 2166 } 2167 2168 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE) 2169 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 2170 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 2171 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE) 2172 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 2173 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 2174 irqflags |= IRQF_ONESHOT; 2175 2176 INIT_KFIFO(le->events); 2177 init_waitqueue_head(&le->wait); 2178 2179 le->device_unregistered_nb.notifier_call = lineevent_unregistered_notify; 2180 ret = blocking_notifier_chain_register(&gdev->device_notifier, 2181 &le->device_unregistered_nb); 2182 if (ret) 2183 goto out_free_le; 2184 2185 /* Request a thread to read the events */ 2186 ret = request_threaded_irq(irq, 2187 lineevent_irq_handler, 2188 lineevent_irq_thread, 2189 irqflags, 2190 le->label, 2191 le); 2192 if (ret) 2193 goto out_free_le; 2194 2195 le->irq = irq; 2196 2197 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 2198 if (fd < 0) { 2199 ret = fd; 2200 goto out_free_le; 2201 } 2202 2203 file = anon_inode_getfile("gpio-event", 2204 &lineevent_fileops, 2205 le, 2206 O_RDONLY | O_CLOEXEC); 2207 if (IS_ERR(file)) { 2208 ret = PTR_ERR(file); 2209 goto out_put_unused_fd; 2210 } 2211 2212 eventreq.fd = fd; 2213 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) { 2214 /* 2215 * fput() will trigger the release() callback, so do not go onto 2216 * the regular error cleanup path here. 2217 */ 2218 fput(file); 2219 put_unused_fd(fd); 2220 return -EFAULT; 2221 } 2222 2223 fd_install(fd, file); 2224 2225 return 0; 2226 2227 out_put_unused_fd: 2228 put_unused_fd(fd); 2229 out_free_le: 2230 lineevent_free(le); 2231 return ret; 2232 } 2233 2234 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2, 2235 struct gpioline_info *info_v1) 2236 { 2237 u64 flagsv2 = info_v2->flags; 2238 2239 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name)); 2240 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer)); 2241 info_v1->line_offset = info_v2->offset; 2242 info_v1->flags = 0; 2243 2244 if (flagsv2 & GPIO_V2_LINE_FLAG_USED) 2245 info_v1->flags |= GPIOLINE_FLAG_KERNEL; 2246 2247 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT) 2248 info_v1->flags |= GPIOLINE_FLAG_IS_OUT; 2249 2250 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 2251 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW; 2252 2253 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN) 2254 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN; 2255 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE) 2256 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE; 2257 2258 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP) 2259 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP; 2260 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) 2261 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN; 2262 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED) 2263 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE; 2264 } 2265 2266 static void gpio_v2_line_info_changed_to_v1( 2267 struct gpio_v2_line_info_changed *lic_v2, 2268 struct gpioline_info_changed *lic_v1) 2269 { 2270 memset(lic_v1, 0, sizeof(*lic_v1)); 2271 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info); 2272 lic_v1->timestamp = lic_v2->timestamp_ns; 2273 lic_v1->event_type = lic_v2->event_type; 2274 } 2275 2276 #endif /* CONFIG_GPIO_CDEV_V1 */ 2277 2278 static void gpio_desc_to_lineinfo(struct gpio_desc *desc, 2279 struct gpio_v2_line_info *info) 2280 { 2281 struct gpio_chip *gc = desc->gdev->chip; 2282 bool ok_for_pinctrl; 2283 unsigned long flags; 2284 u32 debounce_period_us; 2285 unsigned int num_attrs = 0; 2286 2287 memset(info, 0, sizeof(*info)); 2288 info->offset = gpio_chip_hwgpio(desc); 2289 2290 /* 2291 * This function takes a mutex so we must check this before taking 2292 * the spinlock. 2293 * 2294 * FIXME: find a non-racy way to retrieve this information. Maybe a 2295 * lock common to both frameworks? 2296 */ 2297 ok_for_pinctrl = 2298 pinctrl_gpio_can_use_line(gc->base + info->offset); 2299 2300 spin_lock_irqsave(&gpio_lock, flags); 2301 2302 if (desc->name) 2303 strscpy(info->name, desc->name, sizeof(info->name)); 2304 2305 if (desc->label) 2306 strscpy(info->consumer, desc->label, sizeof(info->consumer)); 2307 2308 /* 2309 * Userspace only need to know that the kernel is using this GPIO so 2310 * it can't use it. 2311 */ 2312 info->flags = 0; 2313 if (test_bit(FLAG_REQUESTED, &desc->flags) || 2314 test_bit(FLAG_IS_HOGGED, &desc->flags) || 2315 test_bit(FLAG_USED_AS_IRQ, &desc->flags) || 2316 test_bit(FLAG_EXPORT, &desc->flags) || 2317 test_bit(FLAG_SYSFS, &desc->flags) || 2318 !gpiochip_line_is_valid(gc, info->offset) || 2319 !ok_for_pinctrl) 2320 info->flags |= GPIO_V2_LINE_FLAG_USED; 2321 2322 if (test_bit(FLAG_IS_OUT, &desc->flags)) 2323 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT; 2324 else 2325 info->flags |= GPIO_V2_LINE_FLAG_INPUT; 2326 2327 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) 2328 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW; 2329 2330 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) 2331 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN; 2332 if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) 2333 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE; 2334 2335 if (test_bit(FLAG_BIAS_DISABLE, &desc->flags)) 2336 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED; 2337 if (test_bit(FLAG_PULL_DOWN, &desc->flags)) 2338 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN; 2339 if (test_bit(FLAG_PULL_UP, &desc->flags)) 2340 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP; 2341 2342 if (test_bit(FLAG_EDGE_RISING, &desc->flags)) 2343 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING; 2344 if (test_bit(FLAG_EDGE_FALLING, &desc->flags)) 2345 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING; 2346 2347 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &desc->flags)) 2348 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME; 2349 else if (test_bit(FLAG_EVENT_CLOCK_HTE, &desc->flags)) 2350 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE; 2351 2352 debounce_period_us = READ_ONCE(desc->debounce_period_us); 2353 if (debounce_period_us) { 2354 info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; 2355 info->attrs[num_attrs].debounce_period_us = debounce_period_us; 2356 num_attrs++; 2357 } 2358 info->num_attrs = num_attrs; 2359 2360 spin_unlock_irqrestore(&gpio_lock, flags); 2361 } 2362 2363 struct gpio_chardev_data { 2364 struct gpio_device *gdev; 2365 wait_queue_head_t wait; 2366 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32); 2367 struct notifier_block lineinfo_changed_nb; 2368 struct notifier_block device_unregistered_nb; 2369 unsigned long *watched_lines; 2370 #ifdef CONFIG_GPIO_CDEV_V1 2371 atomic_t watch_abi_version; 2372 #endif 2373 }; 2374 2375 static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip) 2376 { 2377 struct gpio_device *gdev = cdev->gdev; 2378 struct gpiochip_info chipinfo; 2379 2380 memset(&chipinfo, 0, sizeof(chipinfo)); 2381 2382 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name)); 2383 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label)); 2384 chipinfo.lines = gdev->ngpio; 2385 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo))) 2386 return -EFAULT; 2387 return 0; 2388 } 2389 2390 #ifdef CONFIG_GPIO_CDEV_V1 2391 /* 2392 * returns 0 if the versions match, else the previously selected ABI version 2393 */ 2394 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata, 2395 unsigned int version) 2396 { 2397 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version); 2398 2399 if (abiv == version) 2400 return 0; 2401 2402 return abiv; 2403 } 2404 2405 static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip, 2406 bool watch) 2407 { 2408 struct gpio_desc *desc; 2409 struct gpioline_info lineinfo; 2410 struct gpio_v2_line_info lineinfo_v2; 2411 2412 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2413 return -EFAULT; 2414 2415 /* this doubles as a range check on line_offset */ 2416 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset); 2417 if (IS_ERR(desc)) 2418 return PTR_ERR(desc); 2419 2420 if (watch) { 2421 if (lineinfo_ensure_abi_version(cdev, 1)) 2422 return -EPERM; 2423 2424 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines)) 2425 return -EBUSY; 2426 } 2427 2428 gpio_desc_to_lineinfo(desc, &lineinfo_v2); 2429 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); 2430 2431 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2432 if (watch) 2433 clear_bit(lineinfo.line_offset, cdev->watched_lines); 2434 return -EFAULT; 2435 } 2436 2437 return 0; 2438 } 2439 #endif 2440 2441 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, 2442 bool watch) 2443 { 2444 struct gpio_desc *desc; 2445 struct gpio_v2_line_info lineinfo; 2446 2447 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2448 return -EFAULT; 2449 2450 if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding))) 2451 return -EINVAL; 2452 2453 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset); 2454 if (IS_ERR(desc)) 2455 return PTR_ERR(desc); 2456 2457 if (watch) { 2458 #ifdef CONFIG_GPIO_CDEV_V1 2459 if (lineinfo_ensure_abi_version(cdev, 2)) 2460 return -EPERM; 2461 #endif 2462 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines)) 2463 return -EBUSY; 2464 } 2465 gpio_desc_to_lineinfo(desc, &lineinfo); 2466 2467 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2468 if (watch) 2469 clear_bit(lineinfo.offset, cdev->watched_lines); 2470 return -EFAULT; 2471 } 2472 2473 return 0; 2474 } 2475 2476 static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip) 2477 { 2478 __u32 offset; 2479 2480 if (copy_from_user(&offset, ip, sizeof(offset))) 2481 return -EFAULT; 2482 2483 if (offset >= cdev->gdev->ngpio) 2484 return -EINVAL; 2485 2486 if (!test_and_clear_bit(offset, cdev->watched_lines)) 2487 return -EBUSY; 2488 2489 return 0; 2490 } 2491 2492 /* 2493 * gpio_ioctl() - ioctl handler for the GPIO chardev 2494 */ 2495 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 2496 { 2497 struct gpio_chardev_data *cdev = file->private_data; 2498 struct gpio_device *gdev = cdev->gdev; 2499 void __user *ip = (void __user *)arg; 2500 2501 /* We fail any subsequent ioctl():s when the chip is gone */ 2502 if (!gdev->chip) 2503 return -ENODEV; 2504 2505 /* Fill in the struct and pass to userspace */ 2506 switch (cmd) { 2507 case GPIO_GET_CHIPINFO_IOCTL: 2508 return chipinfo_get(cdev, ip); 2509 #ifdef CONFIG_GPIO_CDEV_V1 2510 case GPIO_GET_LINEHANDLE_IOCTL: 2511 return linehandle_create(gdev, ip); 2512 case GPIO_GET_LINEEVENT_IOCTL: 2513 return lineevent_create(gdev, ip); 2514 case GPIO_GET_LINEINFO_IOCTL: 2515 return lineinfo_get_v1(cdev, ip, false); 2516 case GPIO_GET_LINEINFO_WATCH_IOCTL: 2517 return lineinfo_get_v1(cdev, ip, true); 2518 #endif /* CONFIG_GPIO_CDEV_V1 */ 2519 case GPIO_V2_GET_LINEINFO_IOCTL: 2520 return lineinfo_get(cdev, ip, false); 2521 case GPIO_V2_GET_LINEINFO_WATCH_IOCTL: 2522 return lineinfo_get(cdev, ip, true); 2523 case GPIO_V2_GET_LINE_IOCTL: 2524 return linereq_create(gdev, ip); 2525 case GPIO_GET_LINEINFO_UNWATCH_IOCTL: 2526 return lineinfo_unwatch(cdev, ip); 2527 default: 2528 return -EINVAL; 2529 } 2530 } 2531 2532 #ifdef CONFIG_COMPAT 2533 static long gpio_ioctl_compat(struct file *file, unsigned int cmd, 2534 unsigned long arg) 2535 { 2536 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 2537 } 2538 #endif 2539 2540 static int lineinfo_changed_notify(struct notifier_block *nb, 2541 unsigned long action, void *data) 2542 { 2543 struct gpio_chardev_data *cdev = 2544 container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb); 2545 struct gpio_v2_line_info_changed chg; 2546 struct gpio_desc *desc = data; 2547 int ret; 2548 2549 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines)) 2550 return NOTIFY_DONE; 2551 2552 memset(&chg, 0, sizeof(chg)); 2553 chg.event_type = action; 2554 chg.timestamp_ns = ktime_get_ns(); 2555 gpio_desc_to_lineinfo(desc, &chg.info); 2556 2557 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock); 2558 if (ret) 2559 wake_up_poll(&cdev->wait, EPOLLIN); 2560 else 2561 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n"); 2562 2563 return NOTIFY_OK; 2564 } 2565 2566 static int gpio_device_unregistered_notify(struct notifier_block *nb, 2567 unsigned long action, void *data) 2568 { 2569 struct gpio_chardev_data *cdev = container_of(nb, 2570 struct gpio_chardev_data, 2571 device_unregistered_nb); 2572 2573 wake_up_poll(&cdev->wait, EPOLLIN | EPOLLERR); 2574 2575 return NOTIFY_OK; 2576 } 2577 2578 static __poll_t lineinfo_watch_poll_unlocked(struct file *file, 2579 struct poll_table_struct *pollt) 2580 { 2581 struct gpio_chardev_data *cdev = file->private_data; 2582 __poll_t events = 0; 2583 2584 if (!cdev->gdev->chip) 2585 return EPOLLHUP | EPOLLERR; 2586 2587 poll_wait(file, &cdev->wait, pollt); 2588 2589 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events, 2590 &cdev->wait.lock)) 2591 events = EPOLLIN | EPOLLRDNORM; 2592 2593 return events; 2594 } 2595 2596 static __poll_t lineinfo_watch_poll(struct file *file, 2597 struct poll_table_struct *pollt) 2598 { 2599 struct gpio_chardev_data *cdev = file->private_data; 2600 2601 return call_poll_locked(file, pollt, cdev->gdev, 2602 lineinfo_watch_poll_unlocked); 2603 } 2604 2605 static ssize_t lineinfo_watch_read_unlocked(struct file *file, char __user *buf, 2606 size_t count, loff_t *off) 2607 { 2608 struct gpio_chardev_data *cdev = file->private_data; 2609 struct gpio_v2_line_info_changed event; 2610 ssize_t bytes_read = 0; 2611 int ret; 2612 size_t event_size; 2613 2614 if (!cdev->gdev->chip) 2615 return -ENODEV; 2616 2617 #ifndef CONFIG_GPIO_CDEV_V1 2618 event_size = sizeof(struct gpio_v2_line_info_changed); 2619 if (count < event_size) 2620 return -EINVAL; 2621 #endif 2622 2623 do { 2624 spin_lock(&cdev->wait.lock); 2625 if (kfifo_is_empty(&cdev->events)) { 2626 if (bytes_read) { 2627 spin_unlock(&cdev->wait.lock); 2628 return bytes_read; 2629 } 2630 2631 if (file->f_flags & O_NONBLOCK) { 2632 spin_unlock(&cdev->wait.lock); 2633 return -EAGAIN; 2634 } 2635 2636 ret = wait_event_interruptible_locked(cdev->wait, 2637 !kfifo_is_empty(&cdev->events)); 2638 if (ret) { 2639 spin_unlock(&cdev->wait.lock); 2640 return ret; 2641 } 2642 } 2643 #ifdef CONFIG_GPIO_CDEV_V1 2644 /* must be after kfifo check so watch_abi_version is set */ 2645 if (atomic_read(&cdev->watch_abi_version) == 2) 2646 event_size = sizeof(struct gpio_v2_line_info_changed); 2647 else 2648 event_size = sizeof(struct gpioline_info_changed); 2649 if (count < event_size) { 2650 spin_unlock(&cdev->wait.lock); 2651 return -EINVAL; 2652 } 2653 #endif 2654 ret = kfifo_out(&cdev->events, &event, 1); 2655 spin_unlock(&cdev->wait.lock); 2656 if (ret != 1) { 2657 ret = -EIO; 2658 break; 2659 /* We should never get here. See lineevent_read(). */ 2660 } 2661 2662 #ifdef CONFIG_GPIO_CDEV_V1 2663 if (event_size == sizeof(struct gpio_v2_line_info_changed)) { 2664 if (copy_to_user(buf + bytes_read, &event, event_size)) 2665 return -EFAULT; 2666 } else { 2667 struct gpioline_info_changed event_v1; 2668 2669 gpio_v2_line_info_changed_to_v1(&event, &event_v1); 2670 if (copy_to_user(buf + bytes_read, &event_v1, 2671 event_size)) 2672 return -EFAULT; 2673 } 2674 #else 2675 if (copy_to_user(buf + bytes_read, &event, event_size)) 2676 return -EFAULT; 2677 #endif 2678 bytes_read += event_size; 2679 } while (count >= bytes_read + sizeof(event)); 2680 2681 return bytes_read; 2682 } 2683 2684 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, 2685 size_t count, loff_t *off) 2686 { 2687 struct gpio_chardev_data *cdev = file->private_data; 2688 2689 return call_read_locked(file, buf, count, off, cdev->gdev, 2690 lineinfo_watch_read_unlocked); 2691 } 2692 2693 /** 2694 * gpio_chrdev_open() - open the chardev for ioctl operations 2695 * @inode: inode for this chardev 2696 * @file: file struct for storing private data 2697 * Returns 0 on success 2698 */ 2699 static int gpio_chrdev_open(struct inode *inode, struct file *file) 2700 { 2701 struct gpio_device *gdev = container_of(inode->i_cdev, 2702 struct gpio_device, chrdev); 2703 struct gpio_chardev_data *cdev; 2704 int ret = -ENOMEM; 2705 2706 down_read(&gdev->sem); 2707 2708 /* Fail on open if the backing gpiochip is gone */ 2709 if (!gdev->chip) { 2710 ret = -ENODEV; 2711 goto out_unlock; 2712 } 2713 2714 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL); 2715 if (!cdev) 2716 goto out_unlock; 2717 2718 cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL); 2719 if (!cdev->watched_lines) 2720 goto out_free_cdev; 2721 2722 init_waitqueue_head(&cdev->wait); 2723 INIT_KFIFO(cdev->events); 2724 cdev->gdev = gpio_device_get(gdev); 2725 2726 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify; 2727 ret = blocking_notifier_chain_register(&gdev->line_state_notifier, 2728 &cdev->lineinfo_changed_nb); 2729 if (ret) 2730 goto out_free_bitmap; 2731 2732 cdev->device_unregistered_nb.notifier_call = 2733 gpio_device_unregistered_notify; 2734 ret = blocking_notifier_chain_register(&gdev->device_notifier, 2735 &cdev->device_unregistered_nb); 2736 if (ret) 2737 goto out_unregister_line_notifier; 2738 2739 file->private_data = cdev; 2740 2741 ret = nonseekable_open(inode, file); 2742 if (ret) 2743 goto out_unregister_device_notifier; 2744 2745 up_read(&gdev->sem); 2746 2747 return ret; 2748 2749 out_unregister_device_notifier: 2750 blocking_notifier_chain_unregister(&gdev->device_notifier, 2751 &cdev->device_unregistered_nb); 2752 out_unregister_line_notifier: 2753 blocking_notifier_chain_unregister(&gdev->line_state_notifier, 2754 &cdev->lineinfo_changed_nb); 2755 out_free_bitmap: 2756 gpio_device_put(gdev); 2757 bitmap_free(cdev->watched_lines); 2758 out_free_cdev: 2759 kfree(cdev); 2760 out_unlock: 2761 up_read(&gdev->sem); 2762 return ret; 2763 } 2764 2765 /** 2766 * gpio_chrdev_release() - close chardev after ioctl operations 2767 * @inode: inode for this chardev 2768 * @file: file struct for storing private data 2769 * Returns 0 on success 2770 */ 2771 static int gpio_chrdev_release(struct inode *inode, struct file *file) 2772 { 2773 struct gpio_chardev_data *cdev = file->private_data; 2774 struct gpio_device *gdev = cdev->gdev; 2775 2776 bitmap_free(cdev->watched_lines); 2777 blocking_notifier_chain_unregister(&gdev->device_notifier, 2778 &cdev->device_unregistered_nb); 2779 blocking_notifier_chain_unregister(&gdev->line_state_notifier, 2780 &cdev->lineinfo_changed_nb); 2781 gpio_device_put(gdev); 2782 kfree(cdev); 2783 2784 return 0; 2785 } 2786 2787 static const struct file_operations gpio_fileops = { 2788 .release = gpio_chrdev_release, 2789 .open = gpio_chrdev_open, 2790 .poll = lineinfo_watch_poll, 2791 .read = lineinfo_watch_read, 2792 .owner = THIS_MODULE, 2793 .llseek = no_llseek, 2794 .unlocked_ioctl = gpio_ioctl, 2795 #ifdef CONFIG_COMPAT 2796 .compat_ioctl = gpio_ioctl_compat, 2797 #endif 2798 }; 2799 2800 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt) 2801 { 2802 int ret; 2803 2804 cdev_init(&gdev->chrdev, &gpio_fileops); 2805 gdev->chrdev.owner = THIS_MODULE; 2806 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id); 2807 2808 ret = cdev_device_add(&gdev->chrdev, &gdev->dev); 2809 if (ret) 2810 return ret; 2811 2812 chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n", 2813 MAJOR(devt), gdev->id); 2814 2815 return 0; 2816 } 2817 2818 void gpiolib_cdev_unregister(struct gpio_device *gdev) 2819 { 2820 cdev_device_del(&gdev->chrdev, &gdev->dev); 2821 blocking_notifier_call_chain(&gdev->device_notifier, 0, NULL); 2822 } 2823