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 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG); 234 } 235 return 0; 236 } 237 238 static long linehandle_ioctl_unlocked(struct file *file, unsigned int cmd, 239 unsigned long arg) 240 { 241 struct linehandle_state *lh = file->private_data; 242 void __user *ip = (void __user *)arg; 243 struct gpiohandle_data ghd; 244 DECLARE_BITMAP(vals, GPIOHANDLES_MAX); 245 unsigned int i; 246 int ret; 247 248 if (!lh->gdev->chip) 249 return -ENODEV; 250 251 switch (cmd) { 252 case GPIOHANDLE_GET_LINE_VALUES_IOCTL: 253 /* NOTE: It's okay to read values of output lines */ 254 ret = gpiod_get_array_value_complex(false, true, 255 lh->num_descs, lh->descs, 256 NULL, vals); 257 if (ret) 258 return ret; 259 260 memset(&ghd, 0, sizeof(ghd)); 261 for (i = 0; i < lh->num_descs; i++) 262 ghd.values[i] = test_bit(i, vals); 263 264 if (copy_to_user(ip, &ghd, sizeof(ghd))) 265 return -EFAULT; 266 267 return 0; 268 case GPIOHANDLE_SET_LINE_VALUES_IOCTL: 269 /* 270 * All line descriptors were created at once with the same 271 * flags so just check if the first one is really output. 272 */ 273 if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags)) 274 return -EPERM; 275 276 if (copy_from_user(&ghd, ip, sizeof(ghd))) 277 return -EFAULT; 278 279 /* Clamp all values to [0,1] */ 280 for (i = 0; i < lh->num_descs; i++) 281 __assign_bit(i, vals, ghd.values[i]); 282 283 /* Reuse the array setting function */ 284 return gpiod_set_array_value_complex(false, 285 true, 286 lh->num_descs, 287 lh->descs, 288 NULL, 289 vals); 290 case GPIOHANDLE_SET_CONFIG_IOCTL: 291 return linehandle_set_config(lh, ip); 292 default: 293 return -EINVAL; 294 } 295 } 296 297 static long linehandle_ioctl(struct file *file, unsigned int cmd, 298 unsigned long arg) 299 { 300 struct linehandle_state *lh = file->private_data; 301 302 return call_ioctl_locked(file, cmd, arg, lh->gdev, 303 linehandle_ioctl_unlocked); 304 } 305 306 #ifdef CONFIG_COMPAT 307 static long linehandle_ioctl_compat(struct file *file, unsigned int cmd, 308 unsigned long arg) 309 { 310 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 311 } 312 #endif 313 314 static void linehandle_free(struct linehandle_state *lh) 315 { 316 int i; 317 318 for (i = 0; i < lh->num_descs; i++) 319 if (lh->descs[i]) 320 gpiod_free(lh->descs[i]); 321 kfree(lh->label); 322 gpio_device_put(lh->gdev); 323 kfree(lh); 324 } 325 326 static int linehandle_release(struct inode *inode, struct file *file) 327 { 328 linehandle_free(file->private_data); 329 return 0; 330 } 331 332 static const struct file_operations linehandle_fileops = { 333 .release = linehandle_release, 334 .owner = THIS_MODULE, 335 .llseek = noop_llseek, 336 .unlocked_ioctl = linehandle_ioctl, 337 #ifdef CONFIG_COMPAT 338 .compat_ioctl = linehandle_ioctl_compat, 339 #endif 340 }; 341 342 static int linehandle_create(struct gpio_device *gdev, void __user *ip) 343 { 344 struct gpiohandle_request handlereq; 345 struct linehandle_state *lh; 346 struct file *file; 347 int fd, i, ret; 348 u32 lflags; 349 350 if (copy_from_user(&handlereq, ip, sizeof(handlereq))) 351 return -EFAULT; 352 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX)) 353 return -EINVAL; 354 355 lflags = handlereq.flags; 356 357 ret = linehandle_validate_flags(lflags); 358 if (ret) 359 return ret; 360 361 lh = kzalloc(sizeof(*lh), GFP_KERNEL); 362 if (!lh) 363 return -ENOMEM; 364 lh->gdev = gpio_device_get(gdev); 365 366 if (handlereq.consumer_label[0] != '\0') { 367 /* label is only initialized if consumer_label is set */ 368 lh->label = kstrndup(handlereq.consumer_label, 369 sizeof(handlereq.consumer_label) - 1, 370 GFP_KERNEL); 371 if (!lh->label) { 372 ret = -ENOMEM; 373 goto out_free_lh; 374 } 375 } 376 377 lh->num_descs = handlereq.lines; 378 379 /* Request each GPIO */ 380 for (i = 0; i < handlereq.lines; i++) { 381 u32 offset = handlereq.lineoffsets[i]; 382 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset); 383 384 if (IS_ERR(desc)) { 385 ret = PTR_ERR(desc); 386 goto out_free_lh; 387 } 388 389 ret = gpiod_request_user(desc, lh->label); 390 if (ret) 391 goto out_free_lh; 392 lh->descs[i] = desc; 393 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags); 394 395 ret = gpiod_set_transitory(desc, false); 396 if (ret < 0) 397 goto out_free_lh; 398 399 /* 400 * Lines have to be requested explicitly for input 401 * or output, else the line will be treated "as is". 402 */ 403 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { 404 int val = !!handlereq.default_values[i]; 405 406 ret = gpiod_direction_output(desc, val); 407 if (ret) 408 goto out_free_lh; 409 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { 410 ret = gpiod_direction_input(desc); 411 if (ret) 412 goto out_free_lh; 413 } 414 415 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED); 416 417 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 418 offset); 419 } 420 421 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 422 if (fd < 0) { 423 ret = fd; 424 goto out_free_lh; 425 } 426 427 file = anon_inode_getfile("gpio-linehandle", 428 &linehandle_fileops, 429 lh, 430 O_RDONLY | O_CLOEXEC); 431 if (IS_ERR(file)) { 432 ret = PTR_ERR(file); 433 goto out_put_unused_fd; 434 } 435 436 handlereq.fd = fd; 437 if (copy_to_user(ip, &handlereq, sizeof(handlereq))) { 438 /* 439 * fput() will trigger the release() callback, so do not go onto 440 * the regular error cleanup path here. 441 */ 442 fput(file); 443 put_unused_fd(fd); 444 return -EFAULT; 445 } 446 447 fd_install(fd, file); 448 449 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 450 lh->num_descs); 451 452 return 0; 453 454 out_put_unused_fd: 455 put_unused_fd(fd); 456 out_free_lh: 457 linehandle_free(lh); 458 return ret; 459 } 460 #endif /* CONFIG_GPIO_CDEV_V1 */ 461 462 /** 463 * struct line - contains the state of a requested line 464 * @desc: the GPIO descriptor for this line. 465 * @req: the corresponding line request 466 * @irq: the interrupt triggered in response to events on this GPIO 467 * @edflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or 468 * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied 469 * @timestamp_ns: cache for the timestamp storing it between hardirq and 470 * IRQ thread, used to bring the timestamp close to the actual event 471 * @req_seqno: the seqno for the current edge event in the sequence of 472 * events for the corresponding line request. This is drawn from the @req. 473 * @line_seqno: the seqno for the current edge event in the sequence of 474 * events for this line. 475 * @work: the worker that implements software debouncing 476 * @sw_debounced: flag indicating if the software debouncer is active 477 * @level: the current debounced physical level of the line 478 * @hdesc: the Hardware Timestamp Engine (HTE) descriptor 479 * @raw_level: the line level at the time of event 480 * @total_discard_seq: the running counter of the discarded events 481 * @last_seqno: the last sequence number before debounce period expires 482 */ 483 struct line { 484 struct gpio_desc *desc; 485 /* 486 * -- edge detector specific fields -- 487 */ 488 struct linereq *req; 489 unsigned int irq; 490 /* 491 * The flags for the active edge detector configuration. 492 * 493 * edflags is set by linereq_create(), linereq_free(), and 494 * linereq_set_config_unlocked(), which are themselves mutually 495 * exclusive, and is accessed by edge_irq_thread(), 496 * process_hw_ts_thread() and debounce_work_func(), 497 * which can all live with a slightly stale value. 498 */ 499 u64 edflags; 500 /* 501 * timestamp_ns and req_seqno are accessed only by 502 * edge_irq_handler() and edge_irq_thread(), which are themselves 503 * mutually exclusive, so no additional protection is necessary. 504 */ 505 u64 timestamp_ns; 506 u32 req_seqno; 507 /* 508 * line_seqno is accessed by either edge_irq_thread() or 509 * debounce_work_func(), which are themselves mutually exclusive, 510 * so no additional protection is necessary. 511 */ 512 u32 line_seqno; 513 /* 514 * -- debouncer specific fields -- 515 */ 516 struct delayed_work work; 517 /* 518 * sw_debounce is accessed by linereq_set_config(), which is the 519 * only setter, and linereq_get_values(), which can live with a 520 * slightly stale value. 521 */ 522 unsigned int sw_debounced; 523 /* 524 * level is accessed by debounce_work_func(), which is the only 525 * setter, and linereq_get_values() which can live with a slightly 526 * stale value. 527 */ 528 unsigned int level; 529 #ifdef CONFIG_HTE 530 struct hte_ts_desc hdesc; 531 /* 532 * HTE provider sets line level at the time of event. The valid 533 * value is 0 or 1 and negative value for an error. 534 */ 535 int raw_level; 536 /* 537 * when sw_debounce is set on HTE enabled line, this is running 538 * counter of the discarded events. 539 */ 540 u32 total_discard_seq; 541 /* 542 * when sw_debounce is set on HTE enabled line, this variable records 543 * last sequence number before debounce period expires. 544 */ 545 u32 last_seqno; 546 #endif /* CONFIG_HTE */ 547 }; 548 549 /** 550 * struct linereq - contains the state of a userspace line request 551 * @gdev: the GPIO device the line request pertains to 552 * @label: consumer label used to tag GPIO descriptors 553 * @num_lines: the number of lines in the lines array 554 * @wait: wait queue that handles blocking reads of events 555 * @device_unregistered_nb: notifier block for receiving gdev unregister events 556 * @event_buffer_size: the number of elements allocated in @events 557 * @events: KFIFO for the GPIO events 558 * @seqno: the sequence number for edge events generated on all lines in 559 * this line request. Note that this is not used when @num_lines is 1, as 560 * the line_seqno is then the same and is cheaper to calculate. 561 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency 562 * of configuration, particularly multi-step accesses to desc flags. 563 * @lines: the lines held by this line request, with @num_lines elements. 564 */ 565 struct linereq { 566 struct gpio_device *gdev; 567 const char *label; 568 u32 num_lines; 569 wait_queue_head_t wait; 570 struct notifier_block device_unregistered_nb; 571 u32 event_buffer_size; 572 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event); 573 atomic_t seqno; 574 struct mutex config_mutex; 575 struct line lines[]; 576 }; 577 578 #define GPIO_V2_LINE_BIAS_FLAGS \ 579 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \ 580 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \ 581 GPIO_V2_LINE_FLAG_BIAS_DISABLED) 582 583 #define GPIO_V2_LINE_DIRECTION_FLAGS \ 584 (GPIO_V2_LINE_FLAG_INPUT | \ 585 GPIO_V2_LINE_FLAG_OUTPUT) 586 587 #define GPIO_V2_LINE_DRIVE_FLAGS \ 588 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \ 589 GPIO_V2_LINE_FLAG_OPEN_SOURCE) 590 591 #define GPIO_V2_LINE_EDGE_FLAGS \ 592 (GPIO_V2_LINE_FLAG_EDGE_RISING | \ 593 GPIO_V2_LINE_FLAG_EDGE_FALLING) 594 595 #define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS 596 597 #define GPIO_V2_LINE_VALID_FLAGS \ 598 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ 599 GPIO_V2_LINE_DIRECTION_FLAGS | \ 600 GPIO_V2_LINE_DRIVE_FLAGS | \ 601 GPIO_V2_LINE_EDGE_FLAGS | \ 602 GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \ 603 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \ 604 GPIO_V2_LINE_BIAS_FLAGS) 605 606 /* subset of flags relevant for edge detector configuration */ 607 #define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \ 608 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ 609 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \ 610 GPIO_V2_LINE_EDGE_FLAGS) 611 612 static int linereq_unregistered_notify(struct notifier_block *nb, 613 unsigned long action, void *data) 614 { 615 struct linereq *lr = container_of(nb, struct linereq, 616 device_unregistered_nb); 617 618 wake_up_poll(&lr->wait, EPOLLIN | EPOLLERR); 619 620 return NOTIFY_OK; 621 } 622 623 static void linereq_put_event(struct linereq *lr, 624 struct gpio_v2_line_event *le) 625 { 626 bool overflow = false; 627 628 spin_lock(&lr->wait.lock); 629 if (kfifo_is_full(&lr->events)) { 630 overflow = true; 631 kfifo_skip(&lr->events); 632 } 633 kfifo_in(&lr->events, le, 1); 634 spin_unlock(&lr->wait.lock); 635 if (!overflow) 636 wake_up_poll(&lr->wait, EPOLLIN); 637 else 638 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 639 } 640 641 static u64 line_event_timestamp(struct line *line) 642 { 643 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags)) 644 return ktime_get_real_ns(); 645 else if (IS_ENABLED(CONFIG_HTE) && 646 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags)) 647 return line->timestamp_ns; 648 649 return ktime_get_ns(); 650 } 651 652 static u32 line_event_id(int level) 653 { 654 return level ? GPIO_V2_LINE_EVENT_RISING_EDGE : 655 GPIO_V2_LINE_EVENT_FALLING_EDGE; 656 } 657 658 static inline char *make_irq_label(const char *orig) 659 { 660 char *new; 661 662 if (!orig) 663 return NULL; 664 665 new = kstrdup_and_replace(orig, '/', ':', GFP_KERNEL); 666 if (!new) 667 return ERR_PTR(-ENOMEM); 668 669 return new; 670 } 671 672 static inline void free_irq_label(const char *label) 673 { 674 kfree(label); 675 } 676 677 #ifdef CONFIG_HTE 678 679 static enum hte_return process_hw_ts_thread(void *p) 680 { 681 struct line *line; 682 struct linereq *lr; 683 struct gpio_v2_line_event le; 684 u64 edflags; 685 int level; 686 687 if (!p) 688 return HTE_CB_HANDLED; 689 690 line = p; 691 lr = line->req; 692 693 memset(&le, 0, sizeof(le)); 694 695 le.timestamp_ns = line->timestamp_ns; 696 edflags = READ_ONCE(line->edflags); 697 698 switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) { 699 case GPIO_V2_LINE_FLAG_EDGE_BOTH: 700 level = (line->raw_level >= 0) ? 701 line->raw_level : 702 gpiod_get_raw_value_cansleep(line->desc); 703 704 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 705 level = !level; 706 707 le.id = line_event_id(level); 708 break; 709 case GPIO_V2_LINE_FLAG_EDGE_RISING: 710 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 711 break; 712 case GPIO_V2_LINE_FLAG_EDGE_FALLING: 713 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 714 break; 715 default: 716 return HTE_CB_HANDLED; 717 } 718 le.line_seqno = line->line_seqno; 719 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno; 720 le.offset = gpio_chip_hwgpio(line->desc); 721 722 linereq_put_event(lr, &le); 723 724 return HTE_CB_HANDLED; 725 } 726 727 static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p) 728 { 729 struct line *line; 730 struct linereq *lr; 731 int diff_seqno = 0; 732 733 if (!ts || !p) 734 return HTE_CB_HANDLED; 735 736 line = p; 737 line->timestamp_ns = ts->tsc; 738 line->raw_level = ts->raw_level; 739 lr = line->req; 740 741 if (READ_ONCE(line->sw_debounced)) { 742 line->total_discard_seq++; 743 line->last_seqno = ts->seq; 744 mod_delayed_work(system_wq, &line->work, 745 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); 746 } else { 747 if (unlikely(ts->seq < line->line_seqno)) 748 return HTE_CB_HANDLED; 749 750 diff_seqno = ts->seq - line->line_seqno; 751 line->line_seqno = ts->seq; 752 if (lr->num_lines != 1) 753 line->req_seqno = atomic_add_return(diff_seqno, 754 &lr->seqno); 755 756 return HTE_RUN_SECOND_CB; 757 } 758 759 return HTE_CB_HANDLED; 760 } 761 762 static int hte_edge_setup(struct line *line, u64 eflags) 763 { 764 int ret; 765 unsigned long flags = 0; 766 struct hte_ts_desc *hdesc = &line->hdesc; 767 768 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING) 769 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 770 HTE_FALLING_EDGE_TS : 771 HTE_RISING_EDGE_TS; 772 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING) 773 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 774 HTE_RISING_EDGE_TS : 775 HTE_FALLING_EDGE_TS; 776 777 line->total_discard_seq = 0; 778 779 hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL, 780 line->desc); 781 782 ret = hte_ts_get(NULL, hdesc, 0); 783 if (ret) 784 return ret; 785 786 return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread, 787 line); 788 } 789 790 #else 791 792 static int hte_edge_setup(struct line *line, u64 eflags) 793 { 794 return 0; 795 } 796 #endif /* CONFIG_HTE */ 797 798 static irqreturn_t edge_irq_thread(int irq, void *p) 799 { 800 struct line *line = p; 801 struct linereq *lr = line->req; 802 struct gpio_v2_line_event le; 803 804 /* Do not leak kernel stack to userspace */ 805 memset(&le, 0, sizeof(le)); 806 807 if (line->timestamp_ns) { 808 le.timestamp_ns = line->timestamp_ns; 809 } else { 810 /* 811 * We may be running from a nested threaded interrupt in 812 * which case we didn't get the timestamp from 813 * edge_irq_handler(). 814 */ 815 le.timestamp_ns = line_event_timestamp(line); 816 if (lr->num_lines != 1) 817 line->req_seqno = atomic_inc_return(&lr->seqno); 818 } 819 line->timestamp_ns = 0; 820 821 switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) { 822 case GPIO_V2_LINE_FLAG_EDGE_BOTH: 823 le.id = line_event_id(gpiod_get_value_cansleep(line->desc)); 824 break; 825 case GPIO_V2_LINE_FLAG_EDGE_RISING: 826 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 827 break; 828 case GPIO_V2_LINE_FLAG_EDGE_FALLING: 829 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 830 break; 831 default: 832 return IRQ_NONE; 833 } 834 line->line_seqno++; 835 le.line_seqno = line->line_seqno; 836 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno; 837 le.offset = gpio_chip_hwgpio(line->desc); 838 839 linereq_put_event(lr, &le); 840 841 return IRQ_HANDLED; 842 } 843 844 static irqreturn_t edge_irq_handler(int irq, void *p) 845 { 846 struct line *line = p; 847 struct linereq *lr = line->req; 848 849 /* 850 * Just store the timestamp in hardirq context so we get it as 851 * close in time as possible to the actual event. 852 */ 853 line->timestamp_ns = line_event_timestamp(line); 854 855 if (lr->num_lines != 1) 856 line->req_seqno = atomic_inc_return(&lr->seqno); 857 858 return IRQ_WAKE_THREAD; 859 } 860 861 /* 862 * returns the current debounced logical value. 863 */ 864 static bool debounced_value(struct line *line) 865 { 866 bool value; 867 868 /* 869 * minor race - debouncer may be stopped here, so edge_detector_stop() 870 * must leave the value unchanged so the following will read the level 871 * from when the debouncer was last running. 872 */ 873 value = READ_ONCE(line->level); 874 875 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags)) 876 value = !value; 877 878 return value; 879 } 880 881 static irqreturn_t debounce_irq_handler(int irq, void *p) 882 { 883 struct line *line = p; 884 885 mod_delayed_work(system_wq, &line->work, 886 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); 887 888 return IRQ_HANDLED; 889 } 890 891 static void debounce_work_func(struct work_struct *work) 892 { 893 struct gpio_v2_line_event le; 894 struct line *line = container_of(work, struct line, work.work); 895 struct linereq *lr; 896 u64 eflags, edflags = READ_ONCE(line->edflags); 897 int level = -1; 898 #ifdef CONFIG_HTE 899 int diff_seqno; 900 901 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) 902 level = line->raw_level; 903 #endif 904 if (level < 0) 905 level = gpiod_get_raw_value_cansleep(line->desc); 906 if (level < 0) { 907 pr_debug_ratelimited("debouncer failed to read line value\n"); 908 return; 909 } 910 911 if (READ_ONCE(line->level) == level) 912 return; 913 914 WRITE_ONCE(line->level, level); 915 916 /* -- edge detection -- */ 917 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS; 918 if (!eflags) 919 return; 920 921 /* switch from physical level to logical - if they differ */ 922 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 923 level = !level; 924 925 /* ignore edges that are not being monitored */ 926 if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) || 927 ((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level)) 928 return; 929 930 /* Do not leak kernel stack to userspace */ 931 memset(&le, 0, sizeof(le)); 932 933 lr = line->req; 934 le.timestamp_ns = line_event_timestamp(line); 935 le.offset = gpio_chip_hwgpio(line->desc); 936 #ifdef CONFIG_HTE 937 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) { 938 /* discard events except the last one */ 939 line->total_discard_seq -= 1; 940 diff_seqno = line->last_seqno - line->total_discard_seq - 941 line->line_seqno; 942 line->line_seqno = line->last_seqno - line->total_discard_seq; 943 le.line_seqno = line->line_seqno; 944 le.seqno = (lr->num_lines == 1) ? 945 le.line_seqno : atomic_add_return(diff_seqno, &lr->seqno); 946 } else 947 #endif /* CONFIG_HTE */ 948 { 949 line->line_seqno++; 950 le.line_seqno = line->line_seqno; 951 le.seqno = (lr->num_lines == 1) ? 952 le.line_seqno : atomic_inc_return(&lr->seqno); 953 } 954 955 le.id = line_event_id(level); 956 957 linereq_put_event(lr, &le); 958 } 959 960 static int debounce_setup(struct line *line, unsigned int debounce_period_us) 961 { 962 unsigned long irqflags; 963 int ret, level, irq; 964 char *label; 965 966 /* try hardware */ 967 ret = gpiod_set_debounce(line->desc, debounce_period_us); 968 if (!ret) { 969 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 970 return ret; 971 } 972 if (ret != -ENOTSUPP) 973 return ret; 974 975 if (debounce_period_us) { 976 /* setup software debounce */ 977 level = gpiod_get_raw_value_cansleep(line->desc); 978 if (level < 0) 979 return level; 980 981 if (!(IS_ENABLED(CONFIG_HTE) && 982 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) { 983 irq = gpiod_to_irq(line->desc); 984 if (irq < 0) 985 return -ENXIO; 986 987 label = make_irq_label(line->req->label); 988 if (IS_ERR(label)) 989 return -ENOMEM; 990 991 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING; 992 ret = request_irq(irq, debounce_irq_handler, irqflags, 993 label, line); 994 if (ret) { 995 free_irq_label(label); 996 return ret; 997 } 998 line->irq = irq; 999 } else { 1000 ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH); 1001 if (ret) 1002 return ret; 1003 } 1004 1005 WRITE_ONCE(line->level, level); 1006 WRITE_ONCE(line->sw_debounced, 1); 1007 } 1008 return 0; 1009 } 1010 1011 static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc, 1012 unsigned int line_idx) 1013 { 1014 unsigned int i; 1015 u64 mask = BIT_ULL(line_idx); 1016 1017 for (i = 0; i < lc->num_attrs; i++) { 1018 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 1019 (lc->attrs[i].mask & mask)) 1020 return true; 1021 } 1022 return false; 1023 } 1024 1025 static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc, 1026 unsigned int line_idx) 1027 { 1028 unsigned int i; 1029 u64 mask = BIT_ULL(line_idx); 1030 1031 for (i = 0; i < lc->num_attrs; i++) { 1032 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 1033 (lc->attrs[i].mask & mask)) 1034 return lc->attrs[i].attr.debounce_period_us; 1035 } 1036 return 0; 1037 } 1038 1039 static void edge_detector_stop(struct line *line) 1040 { 1041 if (line->irq) { 1042 free_irq_label(free_irq(line->irq, line)); 1043 line->irq = 0; 1044 } 1045 1046 #ifdef CONFIG_HTE 1047 if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) 1048 hte_ts_put(&line->hdesc); 1049 #endif 1050 1051 cancel_delayed_work_sync(&line->work); 1052 WRITE_ONCE(line->sw_debounced, 0); 1053 WRITE_ONCE(line->edflags, 0); 1054 if (line->desc) 1055 WRITE_ONCE(line->desc->debounce_period_us, 0); 1056 /* do not change line->level - see comment in debounced_value() */ 1057 } 1058 1059 static int edge_detector_setup(struct line *line, 1060 struct gpio_v2_line_config *lc, 1061 unsigned int line_idx, u64 edflags) 1062 { 1063 u32 debounce_period_us; 1064 unsigned long irqflags = 0; 1065 u64 eflags; 1066 int irq, ret; 1067 char *label; 1068 1069 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS; 1070 if (eflags && !kfifo_initialized(&line->req->events)) { 1071 ret = kfifo_alloc(&line->req->events, 1072 line->req->event_buffer_size, GFP_KERNEL); 1073 if (ret) 1074 return ret; 1075 } 1076 if (gpio_v2_line_config_debounced(lc, line_idx)) { 1077 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx); 1078 ret = debounce_setup(line, debounce_period_us); 1079 if (ret) 1080 return ret; 1081 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 1082 } 1083 1084 /* detection disabled or sw debouncer will provide edge detection */ 1085 if (!eflags || READ_ONCE(line->sw_debounced)) 1086 return 0; 1087 1088 if (IS_ENABLED(CONFIG_HTE) && 1089 (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1090 return hte_edge_setup(line, edflags); 1091 1092 irq = gpiod_to_irq(line->desc); 1093 if (irq < 0) 1094 return -ENXIO; 1095 1096 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING) 1097 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 1098 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 1099 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING) 1100 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 1101 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 1102 irqflags |= IRQF_ONESHOT; 1103 1104 label = make_irq_label(line->req->label); 1105 if (IS_ERR(label)) 1106 return PTR_ERR(label); 1107 1108 /* Request a thread to read the events */ 1109 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread, 1110 irqflags, label, line); 1111 if (ret) { 1112 free_irq_label(label); 1113 return ret; 1114 } 1115 1116 line->irq = irq; 1117 return 0; 1118 } 1119 1120 static int edge_detector_update(struct line *line, 1121 struct gpio_v2_line_config *lc, 1122 unsigned int line_idx, u64 edflags) 1123 { 1124 u64 active_edflags = READ_ONCE(line->edflags); 1125 unsigned int debounce_period_us = 1126 gpio_v2_line_config_debounce_period(lc, line_idx); 1127 1128 if ((active_edflags == edflags) && 1129 (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us)) 1130 return 0; 1131 1132 /* sw debounced and still will be...*/ 1133 if (debounce_period_us && READ_ONCE(line->sw_debounced)) { 1134 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 1135 return 0; 1136 } 1137 1138 /* reconfiguring edge detection or sw debounce being disabled */ 1139 if ((line->irq && !READ_ONCE(line->sw_debounced)) || 1140 (active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) || 1141 (!debounce_period_us && READ_ONCE(line->sw_debounced))) 1142 edge_detector_stop(line); 1143 1144 return edge_detector_setup(line, lc, line_idx, edflags); 1145 } 1146 1147 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc, 1148 unsigned int line_idx) 1149 { 1150 unsigned int i; 1151 u64 mask = BIT_ULL(line_idx); 1152 1153 for (i = 0; i < lc->num_attrs; i++) { 1154 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) && 1155 (lc->attrs[i].mask & mask)) 1156 return lc->attrs[i].attr.flags; 1157 } 1158 return lc->flags; 1159 } 1160 1161 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc, 1162 unsigned int line_idx) 1163 { 1164 unsigned int i; 1165 u64 mask = BIT_ULL(line_idx); 1166 1167 for (i = 0; i < lc->num_attrs; i++) { 1168 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) && 1169 (lc->attrs[i].mask & mask)) 1170 return !!(lc->attrs[i].attr.values & mask); 1171 } 1172 return 0; 1173 } 1174 1175 static int gpio_v2_line_flags_validate(u64 flags) 1176 { 1177 /* Return an error if an unknown flag is set */ 1178 if (flags & ~GPIO_V2_LINE_VALID_FLAGS) 1179 return -EINVAL; 1180 1181 if (!IS_ENABLED(CONFIG_HTE) && 1182 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1183 return -EOPNOTSUPP; 1184 1185 /* 1186 * Do not allow both INPUT and OUTPUT flags to be set as they are 1187 * contradictory. 1188 */ 1189 if ((flags & GPIO_V2_LINE_FLAG_INPUT) && 1190 (flags & GPIO_V2_LINE_FLAG_OUTPUT)) 1191 return -EINVAL; 1192 1193 /* Only allow one event clock source */ 1194 if (IS_ENABLED(CONFIG_HTE) && 1195 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME) && 1196 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1197 return -EINVAL; 1198 1199 /* Edge detection requires explicit input. */ 1200 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) && 1201 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 1202 return -EINVAL; 1203 1204 /* 1205 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single 1206 * request. If the hardware actually supports enabling both at the 1207 * same time the electrical result would be disastrous. 1208 */ 1209 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) && 1210 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE)) 1211 return -EINVAL; 1212 1213 /* Drive requires explicit output direction. */ 1214 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) && 1215 !(flags & GPIO_V2_LINE_FLAG_OUTPUT)) 1216 return -EINVAL; 1217 1218 /* Bias requires explicit direction. */ 1219 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) && 1220 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS)) 1221 return -EINVAL; 1222 1223 /* Only one bias flag can be set. */ 1224 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) && 1225 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | 1226 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) || 1227 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) && 1228 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) 1229 return -EINVAL; 1230 1231 return 0; 1232 } 1233 1234 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc, 1235 unsigned int num_lines) 1236 { 1237 unsigned int i; 1238 u64 flags; 1239 int ret; 1240 1241 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX) 1242 return -EINVAL; 1243 1244 if (memchr_inv(lc->padding, 0, sizeof(lc->padding))) 1245 return -EINVAL; 1246 1247 for (i = 0; i < num_lines; i++) { 1248 flags = gpio_v2_line_config_flags(lc, i); 1249 ret = gpio_v2_line_flags_validate(flags); 1250 if (ret) 1251 return ret; 1252 1253 /* debounce requires explicit input */ 1254 if (gpio_v2_line_config_debounced(lc, i) && 1255 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 1256 return -EINVAL; 1257 } 1258 return 0; 1259 } 1260 1261 static void gpio_v2_line_config_flags_to_desc_flags(u64 flags, 1262 unsigned long *flagsp) 1263 { 1264 assign_bit(FLAG_ACTIVE_LOW, flagsp, 1265 flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW); 1266 1267 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) 1268 set_bit(FLAG_IS_OUT, flagsp); 1269 else if (flags & GPIO_V2_LINE_FLAG_INPUT) 1270 clear_bit(FLAG_IS_OUT, flagsp); 1271 1272 assign_bit(FLAG_EDGE_RISING, flagsp, 1273 flags & GPIO_V2_LINE_FLAG_EDGE_RISING); 1274 assign_bit(FLAG_EDGE_FALLING, flagsp, 1275 flags & GPIO_V2_LINE_FLAG_EDGE_FALLING); 1276 1277 assign_bit(FLAG_OPEN_DRAIN, flagsp, 1278 flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN); 1279 assign_bit(FLAG_OPEN_SOURCE, flagsp, 1280 flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE); 1281 1282 assign_bit(FLAG_PULL_UP, flagsp, 1283 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP); 1284 assign_bit(FLAG_PULL_DOWN, flagsp, 1285 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN); 1286 assign_bit(FLAG_BIAS_DISABLE, flagsp, 1287 flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED); 1288 1289 assign_bit(FLAG_EVENT_CLOCK_REALTIME, flagsp, 1290 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME); 1291 assign_bit(FLAG_EVENT_CLOCK_HTE, flagsp, 1292 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE); 1293 } 1294 1295 static long linereq_get_values(struct linereq *lr, void __user *ip) 1296 { 1297 struct gpio_v2_line_values lv; 1298 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1299 struct gpio_desc **descs; 1300 unsigned int i, didx, num_get; 1301 bool val; 1302 int ret; 1303 1304 /* NOTE: It's ok to read values of output lines. */ 1305 if (copy_from_user(&lv, ip, sizeof(lv))) 1306 return -EFAULT; 1307 1308 for (num_get = 0, i = 0; i < lr->num_lines; i++) { 1309 if (lv.mask & BIT_ULL(i)) { 1310 num_get++; 1311 descs = &lr->lines[i].desc; 1312 } 1313 } 1314 1315 if (num_get == 0) 1316 return -EINVAL; 1317 1318 if (num_get != 1) { 1319 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL); 1320 if (!descs) 1321 return -ENOMEM; 1322 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1323 if (lv.mask & BIT_ULL(i)) { 1324 descs[didx] = lr->lines[i].desc; 1325 didx++; 1326 } 1327 } 1328 } 1329 ret = gpiod_get_array_value_complex(false, true, num_get, 1330 descs, NULL, vals); 1331 1332 if (num_get != 1) 1333 kfree(descs); 1334 if (ret) 1335 return ret; 1336 1337 lv.bits = 0; 1338 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1339 if (lv.mask & BIT_ULL(i)) { 1340 if (lr->lines[i].sw_debounced) 1341 val = debounced_value(&lr->lines[i]); 1342 else 1343 val = test_bit(didx, vals); 1344 if (val) 1345 lv.bits |= BIT_ULL(i); 1346 didx++; 1347 } 1348 } 1349 1350 if (copy_to_user(ip, &lv, sizeof(lv))) 1351 return -EFAULT; 1352 1353 return 0; 1354 } 1355 1356 static long linereq_set_values_unlocked(struct linereq *lr, 1357 struct gpio_v2_line_values *lv) 1358 { 1359 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1360 struct gpio_desc **descs; 1361 unsigned int i, didx, num_set; 1362 int ret; 1363 1364 bitmap_zero(vals, GPIO_V2_LINES_MAX); 1365 for (num_set = 0, i = 0; i < lr->num_lines; i++) { 1366 if (lv->mask & BIT_ULL(i)) { 1367 if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags)) 1368 return -EPERM; 1369 if (lv->bits & BIT_ULL(i)) 1370 __set_bit(num_set, vals); 1371 num_set++; 1372 descs = &lr->lines[i].desc; 1373 } 1374 } 1375 if (num_set == 0) 1376 return -EINVAL; 1377 1378 if (num_set != 1) { 1379 /* build compacted desc array and values */ 1380 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL); 1381 if (!descs) 1382 return -ENOMEM; 1383 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1384 if (lv->mask & BIT_ULL(i)) { 1385 descs[didx] = lr->lines[i].desc; 1386 didx++; 1387 } 1388 } 1389 } 1390 ret = gpiod_set_array_value_complex(false, true, num_set, 1391 descs, NULL, vals); 1392 1393 if (num_set != 1) 1394 kfree(descs); 1395 return ret; 1396 } 1397 1398 static long linereq_set_values(struct linereq *lr, void __user *ip) 1399 { 1400 struct gpio_v2_line_values lv; 1401 int ret; 1402 1403 if (copy_from_user(&lv, ip, sizeof(lv))) 1404 return -EFAULT; 1405 1406 mutex_lock(&lr->config_mutex); 1407 1408 ret = linereq_set_values_unlocked(lr, &lv); 1409 1410 mutex_unlock(&lr->config_mutex); 1411 1412 return ret; 1413 } 1414 1415 static long linereq_set_config_unlocked(struct linereq *lr, 1416 struct gpio_v2_line_config *lc) 1417 { 1418 struct gpio_desc *desc; 1419 struct line *line; 1420 unsigned int i; 1421 u64 flags, edflags; 1422 int ret; 1423 1424 for (i = 0; i < lr->num_lines; i++) { 1425 line = &lr->lines[i]; 1426 desc = lr->lines[i].desc; 1427 flags = gpio_v2_line_config_flags(lc, i); 1428 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1429 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS; 1430 /* 1431 * Lines have to be requested explicitly for input 1432 * or output, else the line will be treated "as is". 1433 */ 1434 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1435 int val = gpio_v2_line_config_output_value(lc, i); 1436 1437 edge_detector_stop(line); 1438 ret = gpiod_direction_output(desc, val); 1439 if (ret) 1440 return ret; 1441 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1442 ret = gpiod_direction_input(desc); 1443 if (ret) 1444 return ret; 1445 1446 ret = edge_detector_update(line, lc, i, edflags); 1447 if (ret) 1448 return ret; 1449 } 1450 1451 WRITE_ONCE(line->edflags, edflags); 1452 1453 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG); 1454 } 1455 return 0; 1456 } 1457 1458 static long linereq_set_config(struct linereq *lr, void __user *ip) 1459 { 1460 struct gpio_v2_line_config lc; 1461 int ret; 1462 1463 if (copy_from_user(&lc, ip, sizeof(lc))) 1464 return -EFAULT; 1465 1466 ret = gpio_v2_line_config_validate(&lc, lr->num_lines); 1467 if (ret) 1468 return ret; 1469 1470 mutex_lock(&lr->config_mutex); 1471 1472 ret = linereq_set_config_unlocked(lr, &lc); 1473 1474 mutex_unlock(&lr->config_mutex); 1475 1476 return ret; 1477 } 1478 1479 static long linereq_ioctl_unlocked(struct file *file, unsigned int cmd, 1480 unsigned long arg) 1481 { 1482 struct linereq *lr = file->private_data; 1483 void __user *ip = (void __user *)arg; 1484 1485 if (!lr->gdev->chip) 1486 return -ENODEV; 1487 1488 switch (cmd) { 1489 case GPIO_V2_LINE_GET_VALUES_IOCTL: 1490 return linereq_get_values(lr, ip); 1491 case GPIO_V2_LINE_SET_VALUES_IOCTL: 1492 return linereq_set_values(lr, ip); 1493 case GPIO_V2_LINE_SET_CONFIG_IOCTL: 1494 return linereq_set_config(lr, ip); 1495 default: 1496 return -EINVAL; 1497 } 1498 } 1499 1500 static long linereq_ioctl(struct file *file, unsigned int cmd, 1501 unsigned long arg) 1502 { 1503 struct linereq *lr = file->private_data; 1504 1505 return call_ioctl_locked(file, cmd, arg, lr->gdev, 1506 linereq_ioctl_unlocked); 1507 } 1508 1509 #ifdef CONFIG_COMPAT 1510 static long linereq_ioctl_compat(struct file *file, unsigned int cmd, 1511 unsigned long arg) 1512 { 1513 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1514 } 1515 #endif 1516 1517 static __poll_t linereq_poll_unlocked(struct file *file, 1518 struct poll_table_struct *wait) 1519 { 1520 struct linereq *lr = file->private_data; 1521 __poll_t events = 0; 1522 1523 if (!lr->gdev->chip) 1524 return EPOLLHUP | EPOLLERR; 1525 1526 poll_wait(file, &lr->wait, wait); 1527 1528 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events, 1529 &lr->wait.lock)) 1530 events = EPOLLIN | EPOLLRDNORM; 1531 1532 return events; 1533 } 1534 1535 static __poll_t linereq_poll(struct file *file, 1536 struct poll_table_struct *wait) 1537 { 1538 struct linereq *lr = file->private_data; 1539 1540 return call_poll_locked(file, wait, lr->gdev, linereq_poll_unlocked); 1541 } 1542 1543 static ssize_t linereq_read_unlocked(struct file *file, char __user *buf, 1544 size_t count, loff_t *f_ps) 1545 { 1546 struct linereq *lr = file->private_data; 1547 struct gpio_v2_line_event le; 1548 ssize_t bytes_read = 0; 1549 int ret; 1550 1551 if (!lr->gdev->chip) 1552 return -ENODEV; 1553 1554 if (count < sizeof(le)) 1555 return -EINVAL; 1556 1557 do { 1558 spin_lock(&lr->wait.lock); 1559 if (kfifo_is_empty(&lr->events)) { 1560 if (bytes_read) { 1561 spin_unlock(&lr->wait.lock); 1562 return bytes_read; 1563 } 1564 1565 if (file->f_flags & O_NONBLOCK) { 1566 spin_unlock(&lr->wait.lock); 1567 return -EAGAIN; 1568 } 1569 1570 ret = wait_event_interruptible_locked(lr->wait, 1571 !kfifo_is_empty(&lr->events)); 1572 if (ret) { 1573 spin_unlock(&lr->wait.lock); 1574 return ret; 1575 } 1576 } 1577 1578 ret = kfifo_out(&lr->events, &le, 1); 1579 spin_unlock(&lr->wait.lock); 1580 if (ret != 1) { 1581 /* 1582 * This should never happen - we were holding the 1583 * lock from the moment we learned the fifo is no 1584 * longer empty until now. 1585 */ 1586 ret = -EIO; 1587 break; 1588 } 1589 1590 if (copy_to_user(buf + bytes_read, &le, sizeof(le))) 1591 return -EFAULT; 1592 bytes_read += sizeof(le); 1593 } while (count >= bytes_read + sizeof(le)); 1594 1595 return bytes_read; 1596 } 1597 1598 static ssize_t linereq_read(struct file *file, char __user *buf, 1599 size_t count, loff_t *f_ps) 1600 { 1601 struct linereq *lr = file->private_data; 1602 1603 return call_read_locked(file, buf, count, f_ps, lr->gdev, 1604 linereq_read_unlocked); 1605 } 1606 1607 static void linereq_free(struct linereq *lr) 1608 { 1609 unsigned int i; 1610 1611 if (lr->device_unregistered_nb.notifier_call) 1612 blocking_notifier_chain_unregister(&lr->gdev->device_notifier, 1613 &lr->device_unregistered_nb); 1614 1615 for (i = 0; i < lr->num_lines; i++) { 1616 if (lr->lines[i].desc) { 1617 edge_detector_stop(&lr->lines[i]); 1618 gpiod_free(lr->lines[i].desc); 1619 } 1620 } 1621 kfifo_free(&lr->events); 1622 kfree(lr->label); 1623 gpio_device_put(lr->gdev); 1624 kfree(lr); 1625 } 1626 1627 static int linereq_release(struct inode *inode, struct file *file) 1628 { 1629 struct linereq *lr = file->private_data; 1630 1631 linereq_free(lr); 1632 return 0; 1633 } 1634 1635 #ifdef CONFIG_PROC_FS 1636 static void linereq_show_fdinfo(struct seq_file *out, struct file *file) 1637 { 1638 struct linereq *lr = file->private_data; 1639 struct device *dev = &lr->gdev->dev; 1640 u16 i; 1641 1642 seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev)); 1643 1644 for (i = 0; i < lr->num_lines; i++) 1645 seq_printf(out, "gpio-line:\t%d\n", 1646 gpio_chip_hwgpio(lr->lines[i].desc)); 1647 } 1648 #endif 1649 1650 static const struct file_operations line_fileops = { 1651 .release = linereq_release, 1652 .read = linereq_read, 1653 .poll = linereq_poll, 1654 .owner = THIS_MODULE, 1655 .llseek = noop_llseek, 1656 .unlocked_ioctl = linereq_ioctl, 1657 #ifdef CONFIG_COMPAT 1658 .compat_ioctl = linereq_ioctl_compat, 1659 #endif 1660 #ifdef CONFIG_PROC_FS 1661 .show_fdinfo = linereq_show_fdinfo, 1662 #endif 1663 }; 1664 1665 static int linereq_create(struct gpio_device *gdev, void __user *ip) 1666 { 1667 struct gpio_v2_line_request ulr; 1668 struct gpio_v2_line_config *lc; 1669 struct linereq *lr; 1670 struct file *file; 1671 u64 flags, edflags; 1672 unsigned int i; 1673 int fd, ret; 1674 1675 if (copy_from_user(&ulr, ip, sizeof(ulr))) 1676 return -EFAULT; 1677 1678 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX)) 1679 return -EINVAL; 1680 1681 if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding))) 1682 return -EINVAL; 1683 1684 lc = &ulr.config; 1685 ret = gpio_v2_line_config_validate(lc, ulr.num_lines); 1686 if (ret) 1687 return ret; 1688 1689 lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL); 1690 if (!lr) 1691 return -ENOMEM; 1692 1693 lr->gdev = gpio_device_get(gdev); 1694 1695 for (i = 0; i < ulr.num_lines; i++) { 1696 lr->lines[i].req = lr; 1697 WRITE_ONCE(lr->lines[i].sw_debounced, 0); 1698 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func); 1699 } 1700 1701 if (ulr.consumer[0] != '\0') { 1702 /* label is only initialized if consumer is set */ 1703 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1, 1704 GFP_KERNEL); 1705 if (!lr->label) { 1706 ret = -ENOMEM; 1707 goto out_free_linereq; 1708 } 1709 } 1710 1711 mutex_init(&lr->config_mutex); 1712 init_waitqueue_head(&lr->wait); 1713 lr->event_buffer_size = ulr.event_buffer_size; 1714 if (lr->event_buffer_size == 0) 1715 lr->event_buffer_size = ulr.num_lines * 16; 1716 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16) 1717 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16; 1718 1719 atomic_set(&lr->seqno, 0); 1720 lr->num_lines = ulr.num_lines; 1721 1722 /* Request each GPIO */ 1723 for (i = 0; i < ulr.num_lines; i++) { 1724 u32 offset = ulr.offsets[i]; 1725 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset); 1726 1727 if (IS_ERR(desc)) { 1728 ret = PTR_ERR(desc); 1729 goto out_free_linereq; 1730 } 1731 1732 ret = gpiod_request_user(desc, lr->label); 1733 if (ret) 1734 goto out_free_linereq; 1735 1736 lr->lines[i].desc = desc; 1737 flags = gpio_v2_line_config_flags(lc, i); 1738 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1739 1740 ret = gpiod_set_transitory(desc, false); 1741 if (ret < 0) 1742 goto out_free_linereq; 1743 1744 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS; 1745 /* 1746 * Lines have to be requested explicitly for input 1747 * or output, else the line will be treated "as is". 1748 */ 1749 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1750 int val = gpio_v2_line_config_output_value(lc, i); 1751 1752 ret = gpiod_direction_output(desc, val); 1753 if (ret) 1754 goto out_free_linereq; 1755 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1756 ret = gpiod_direction_input(desc); 1757 if (ret) 1758 goto out_free_linereq; 1759 1760 ret = edge_detector_setup(&lr->lines[i], lc, i, 1761 edflags); 1762 if (ret) 1763 goto out_free_linereq; 1764 } 1765 1766 lr->lines[i].edflags = edflags; 1767 1768 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED); 1769 1770 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 1771 offset); 1772 } 1773 1774 lr->device_unregistered_nb.notifier_call = linereq_unregistered_notify; 1775 ret = blocking_notifier_chain_register(&gdev->device_notifier, 1776 &lr->device_unregistered_nb); 1777 if (ret) 1778 goto out_free_linereq; 1779 1780 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 1781 if (fd < 0) { 1782 ret = fd; 1783 goto out_free_linereq; 1784 } 1785 1786 file = anon_inode_getfile("gpio-line", &line_fileops, lr, 1787 O_RDONLY | O_CLOEXEC); 1788 if (IS_ERR(file)) { 1789 ret = PTR_ERR(file); 1790 goto out_put_unused_fd; 1791 } 1792 1793 ulr.fd = fd; 1794 if (copy_to_user(ip, &ulr, sizeof(ulr))) { 1795 /* 1796 * fput() will trigger the release() callback, so do not go onto 1797 * the regular error cleanup path here. 1798 */ 1799 fput(file); 1800 put_unused_fd(fd); 1801 return -EFAULT; 1802 } 1803 1804 fd_install(fd, file); 1805 1806 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 1807 lr->num_lines); 1808 1809 return 0; 1810 1811 out_put_unused_fd: 1812 put_unused_fd(fd); 1813 out_free_linereq: 1814 linereq_free(lr); 1815 return ret; 1816 } 1817 1818 #ifdef CONFIG_GPIO_CDEV_V1 1819 1820 /* 1821 * GPIO line event management 1822 */ 1823 1824 /** 1825 * struct lineevent_state - contains the state of a userspace event 1826 * @gdev: the GPIO device the event pertains to 1827 * @label: consumer label used to tag descriptors 1828 * @desc: the GPIO descriptor held by this event 1829 * @eflags: the event flags this line was requested with 1830 * @irq: the interrupt that trigger in response to events on this GPIO 1831 * @wait: wait queue that handles blocking reads of events 1832 * @device_unregistered_nb: notifier block for receiving gdev unregister events 1833 * @events: KFIFO for the GPIO events 1834 * @timestamp: cache for the timestamp storing it between hardirq 1835 * and IRQ thread, used to bring the timestamp close to the actual 1836 * event 1837 */ 1838 struct lineevent_state { 1839 struct gpio_device *gdev; 1840 const char *label; 1841 struct gpio_desc *desc; 1842 u32 eflags; 1843 int irq; 1844 wait_queue_head_t wait; 1845 struct notifier_block device_unregistered_nb; 1846 DECLARE_KFIFO(events, struct gpioevent_data, 16); 1847 u64 timestamp; 1848 }; 1849 1850 #define GPIOEVENT_REQUEST_VALID_FLAGS \ 1851 (GPIOEVENT_REQUEST_RISING_EDGE | \ 1852 GPIOEVENT_REQUEST_FALLING_EDGE) 1853 1854 static __poll_t lineevent_poll_unlocked(struct file *file, 1855 struct poll_table_struct *wait) 1856 { 1857 struct lineevent_state *le = file->private_data; 1858 __poll_t events = 0; 1859 1860 if (!le->gdev->chip) 1861 return EPOLLHUP | EPOLLERR; 1862 1863 poll_wait(file, &le->wait, wait); 1864 1865 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock)) 1866 events = EPOLLIN | EPOLLRDNORM; 1867 1868 return events; 1869 } 1870 1871 static __poll_t lineevent_poll(struct file *file, 1872 struct poll_table_struct *wait) 1873 { 1874 struct lineevent_state *le = file->private_data; 1875 1876 return call_poll_locked(file, wait, le->gdev, lineevent_poll_unlocked); 1877 } 1878 1879 static int lineevent_unregistered_notify(struct notifier_block *nb, 1880 unsigned long action, void *data) 1881 { 1882 struct lineevent_state *le = container_of(nb, struct lineevent_state, 1883 device_unregistered_nb); 1884 1885 wake_up_poll(&le->wait, EPOLLIN | EPOLLERR); 1886 1887 return NOTIFY_OK; 1888 } 1889 1890 struct compat_gpioeevent_data { 1891 compat_u64 timestamp; 1892 u32 id; 1893 }; 1894 1895 static ssize_t lineevent_read_unlocked(struct file *file, char __user *buf, 1896 size_t count, loff_t *f_ps) 1897 { 1898 struct lineevent_state *le = file->private_data; 1899 struct gpioevent_data ge; 1900 ssize_t bytes_read = 0; 1901 ssize_t ge_size; 1902 int ret; 1903 1904 if (!le->gdev->chip) 1905 return -ENODEV; 1906 1907 /* 1908 * When compatible system call is being used the struct gpioevent_data, 1909 * in case of at least ia32, has different size due to the alignment 1910 * differences. Because we have first member 64 bits followed by one of 1911 * 32 bits there is no gap between them. The only difference is the 1912 * padding at the end of the data structure. Hence, we calculate the 1913 * actual sizeof() and pass this as an argument to copy_to_user() to 1914 * drop unneeded bytes from the output. 1915 */ 1916 if (compat_need_64bit_alignment_fixup()) 1917 ge_size = sizeof(struct compat_gpioeevent_data); 1918 else 1919 ge_size = sizeof(struct gpioevent_data); 1920 if (count < ge_size) 1921 return -EINVAL; 1922 1923 do { 1924 spin_lock(&le->wait.lock); 1925 if (kfifo_is_empty(&le->events)) { 1926 if (bytes_read) { 1927 spin_unlock(&le->wait.lock); 1928 return bytes_read; 1929 } 1930 1931 if (file->f_flags & O_NONBLOCK) { 1932 spin_unlock(&le->wait.lock); 1933 return -EAGAIN; 1934 } 1935 1936 ret = wait_event_interruptible_locked(le->wait, 1937 !kfifo_is_empty(&le->events)); 1938 if (ret) { 1939 spin_unlock(&le->wait.lock); 1940 return ret; 1941 } 1942 } 1943 1944 ret = kfifo_out(&le->events, &ge, 1); 1945 spin_unlock(&le->wait.lock); 1946 if (ret != 1) { 1947 /* 1948 * This should never happen - we were holding the lock 1949 * from the moment we learned the fifo is no longer 1950 * empty until now. 1951 */ 1952 ret = -EIO; 1953 break; 1954 } 1955 1956 if (copy_to_user(buf + bytes_read, &ge, ge_size)) 1957 return -EFAULT; 1958 bytes_read += ge_size; 1959 } while (count >= bytes_read + ge_size); 1960 1961 return bytes_read; 1962 } 1963 1964 static ssize_t lineevent_read(struct file *file, char __user *buf, 1965 size_t count, loff_t *f_ps) 1966 { 1967 struct lineevent_state *le = file->private_data; 1968 1969 return call_read_locked(file, buf, count, f_ps, le->gdev, 1970 lineevent_read_unlocked); 1971 } 1972 1973 static void lineevent_free(struct lineevent_state *le) 1974 { 1975 if (le->device_unregistered_nb.notifier_call) 1976 blocking_notifier_chain_unregister(&le->gdev->device_notifier, 1977 &le->device_unregistered_nb); 1978 if (le->irq) 1979 free_irq_label(free_irq(le->irq, le)); 1980 if (le->desc) 1981 gpiod_free(le->desc); 1982 kfree(le->label); 1983 gpio_device_put(le->gdev); 1984 kfree(le); 1985 } 1986 1987 static int lineevent_release(struct inode *inode, struct file *file) 1988 { 1989 lineevent_free(file->private_data); 1990 return 0; 1991 } 1992 1993 static long lineevent_ioctl_unlocked(struct file *file, unsigned int cmd, 1994 unsigned long arg) 1995 { 1996 struct lineevent_state *le = file->private_data; 1997 void __user *ip = (void __user *)arg; 1998 struct gpiohandle_data ghd; 1999 2000 if (!le->gdev->chip) 2001 return -ENODEV; 2002 2003 /* 2004 * We can get the value for an event line but not set it, 2005 * because it is input by definition. 2006 */ 2007 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { 2008 int val; 2009 2010 memset(&ghd, 0, sizeof(ghd)); 2011 2012 val = gpiod_get_value_cansleep(le->desc); 2013 if (val < 0) 2014 return val; 2015 ghd.values[0] = val; 2016 2017 if (copy_to_user(ip, &ghd, sizeof(ghd))) 2018 return -EFAULT; 2019 2020 return 0; 2021 } 2022 return -EINVAL; 2023 } 2024 2025 static long lineevent_ioctl(struct file *file, unsigned int cmd, 2026 unsigned long arg) 2027 { 2028 struct lineevent_state *le = file->private_data; 2029 2030 return call_ioctl_locked(file, cmd, arg, le->gdev, 2031 lineevent_ioctl_unlocked); 2032 } 2033 2034 #ifdef CONFIG_COMPAT 2035 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd, 2036 unsigned long arg) 2037 { 2038 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 2039 } 2040 #endif 2041 2042 static const struct file_operations lineevent_fileops = { 2043 .release = lineevent_release, 2044 .read = lineevent_read, 2045 .poll = lineevent_poll, 2046 .owner = THIS_MODULE, 2047 .llseek = noop_llseek, 2048 .unlocked_ioctl = lineevent_ioctl, 2049 #ifdef CONFIG_COMPAT 2050 .compat_ioctl = lineevent_ioctl_compat, 2051 #endif 2052 }; 2053 2054 static irqreturn_t lineevent_irq_thread(int irq, void *p) 2055 { 2056 struct lineevent_state *le = p; 2057 struct gpioevent_data ge; 2058 int ret; 2059 2060 /* Do not leak kernel stack to userspace */ 2061 memset(&ge, 0, sizeof(ge)); 2062 2063 /* 2064 * We may be running from a nested threaded interrupt in which case 2065 * we didn't get the timestamp from lineevent_irq_handler(). 2066 */ 2067 if (!le->timestamp) 2068 ge.timestamp = ktime_get_ns(); 2069 else 2070 ge.timestamp = le->timestamp; 2071 2072 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE 2073 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 2074 int level = gpiod_get_value_cansleep(le->desc); 2075 2076 if (level) 2077 /* Emit low-to-high event */ 2078 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 2079 else 2080 /* Emit high-to-low event */ 2081 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 2082 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) { 2083 /* Emit low-to-high event */ 2084 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 2085 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 2086 /* Emit high-to-low event */ 2087 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 2088 } else { 2089 return IRQ_NONE; 2090 } 2091 2092 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge, 2093 1, &le->wait.lock); 2094 if (ret) 2095 wake_up_poll(&le->wait, EPOLLIN); 2096 else 2097 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 2098 2099 return IRQ_HANDLED; 2100 } 2101 2102 static irqreturn_t lineevent_irq_handler(int irq, void *p) 2103 { 2104 struct lineevent_state *le = p; 2105 2106 /* 2107 * Just store the timestamp in hardirq context so we get it as 2108 * close in time as possible to the actual event. 2109 */ 2110 le->timestamp = ktime_get_ns(); 2111 2112 return IRQ_WAKE_THREAD; 2113 } 2114 2115 static int lineevent_create(struct gpio_device *gdev, void __user *ip) 2116 { 2117 struct gpioevent_request eventreq; 2118 struct lineevent_state *le; 2119 struct gpio_desc *desc; 2120 struct file *file; 2121 u32 offset; 2122 u32 lflags; 2123 u32 eflags; 2124 int fd; 2125 int ret; 2126 int irq, irqflags = 0; 2127 char *label; 2128 2129 if (copy_from_user(&eventreq, ip, sizeof(eventreq))) 2130 return -EFAULT; 2131 2132 offset = eventreq.lineoffset; 2133 lflags = eventreq.handleflags; 2134 eflags = eventreq.eventflags; 2135 2136 desc = gpiochip_get_desc(gdev->chip, offset); 2137 if (IS_ERR(desc)) 2138 return PTR_ERR(desc); 2139 2140 /* Return an error if a unknown flag is set */ 2141 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) || 2142 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS)) 2143 return -EINVAL; 2144 2145 /* This is just wrong: we don't look for events on output lines */ 2146 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) || 2147 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 2148 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 2149 return -EINVAL; 2150 2151 /* Only one bias flag can be set. */ 2152 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 2153 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 2154 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 2155 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 2156 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 2157 return -EINVAL; 2158 2159 le = kzalloc(sizeof(*le), GFP_KERNEL); 2160 if (!le) 2161 return -ENOMEM; 2162 le->gdev = gpio_device_get(gdev); 2163 2164 if (eventreq.consumer_label[0] != '\0') { 2165 /* label is only initialized if consumer_label is set */ 2166 le->label = kstrndup(eventreq.consumer_label, 2167 sizeof(eventreq.consumer_label) - 1, 2168 GFP_KERNEL); 2169 if (!le->label) { 2170 ret = -ENOMEM; 2171 goto out_free_le; 2172 } 2173 } 2174 2175 ret = gpiod_request_user(desc, le->label); 2176 if (ret) 2177 goto out_free_le; 2178 le->desc = desc; 2179 le->eflags = eflags; 2180 2181 linehandle_flags_to_desc_flags(lflags, &desc->flags); 2182 2183 ret = gpiod_direction_input(desc); 2184 if (ret) 2185 goto out_free_le; 2186 2187 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED); 2188 2189 irq = gpiod_to_irq(desc); 2190 if (irq <= 0) { 2191 ret = -ENODEV; 2192 goto out_free_le; 2193 } 2194 2195 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE) 2196 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 2197 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 2198 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE) 2199 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 2200 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 2201 irqflags |= IRQF_ONESHOT; 2202 2203 INIT_KFIFO(le->events); 2204 init_waitqueue_head(&le->wait); 2205 2206 le->device_unregistered_nb.notifier_call = lineevent_unregistered_notify; 2207 ret = blocking_notifier_chain_register(&gdev->device_notifier, 2208 &le->device_unregistered_nb); 2209 if (ret) 2210 goto out_free_le; 2211 2212 label = make_irq_label(le->label); 2213 if (IS_ERR(label)) { 2214 ret = PTR_ERR(label); 2215 goto out_free_le; 2216 } 2217 2218 /* Request a thread to read the events */ 2219 ret = request_threaded_irq(irq, 2220 lineevent_irq_handler, 2221 lineevent_irq_thread, 2222 irqflags, 2223 label, 2224 le); 2225 if (ret) { 2226 free_irq_label(label); 2227 goto out_free_le; 2228 } 2229 2230 le->irq = irq; 2231 2232 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 2233 if (fd < 0) { 2234 ret = fd; 2235 goto out_free_le; 2236 } 2237 2238 file = anon_inode_getfile("gpio-event", 2239 &lineevent_fileops, 2240 le, 2241 O_RDONLY | O_CLOEXEC); 2242 if (IS_ERR(file)) { 2243 ret = PTR_ERR(file); 2244 goto out_put_unused_fd; 2245 } 2246 2247 eventreq.fd = fd; 2248 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) { 2249 /* 2250 * fput() will trigger the release() callback, so do not go onto 2251 * the regular error cleanup path here. 2252 */ 2253 fput(file); 2254 put_unused_fd(fd); 2255 return -EFAULT; 2256 } 2257 2258 fd_install(fd, file); 2259 2260 return 0; 2261 2262 out_put_unused_fd: 2263 put_unused_fd(fd); 2264 out_free_le: 2265 lineevent_free(le); 2266 return ret; 2267 } 2268 2269 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2, 2270 struct gpioline_info *info_v1) 2271 { 2272 u64 flagsv2 = info_v2->flags; 2273 2274 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name)); 2275 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer)); 2276 info_v1->line_offset = info_v2->offset; 2277 info_v1->flags = 0; 2278 2279 if (flagsv2 & GPIO_V2_LINE_FLAG_USED) 2280 info_v1->flags |= GPIOLINE_FLAG_KERNEL; 2281 2282 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT) 2283 info_v1->flags |= GPIOLINE_FLAG_IS_OUT; 2284 2285 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 2286 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW; 2287 2288 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN) 2289 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN; 2290 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE) 2291 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE; 2292 2293 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP) 2294 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP; 2295 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) 2296 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN; 2297 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED) 2298 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE; 2299 } 2300 2301 static void gpio_v2_line_info_changed_to_v1( 2302 struct gpio_v2_line_info_changed *lic_v2, 2303 struct gpioline_info_changed *lic_v1) 2304 { 2305 memset(lic_v1, 0, sizeof(*lic_v1)); 2306 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info); 2307 lic_v1->timestamp = lic_v2->timestamp_ns; 2308 lic_v1->event_type = lic_v2->event_type; 2309 } 2310 2311 #endif /* CONFIG_GPIO_CDEV_V1 */ 2312 2313 static void gpio_desc_to_lineinfo(struct gpio_desc *desc, 2314 struct gpio_v2_line_info *info) 2315 { 2316 struct gpio_chip *gc = desc->gdev->chip; 2317 bool ok_for_pinctrl; 2318 unsigned long flags; 2319 u32 debounce_period_us; 2320 unsigned int num_attrs = 0; 2321 2322 memset(info, 0, sizeof(*info)); 2323 info->offset = gpio_chip_hwgpio(desc); 2324 2325 /* 2326 * This function takes a mutex so we must check this before taking 2327 * the spinlock. 2328 * 2329 * FIXME: find a non-racy way to retrieve this information. Maybe a 2330 * lock common to both frameworks? 2331 */ 2332 ok_for_pinctrl = 2333 pinctrl_gpio_can_use_line(gc->base + info->offset); 2334 2335 spin_lock_irqsave(&gpio_lock, flags); 2336 2337 if (desc->name) 2338 strscpy(info->name, desc->name, sizeof(info->name)); 2339 2340 if (desc->label) 2341 strscpy(info->consumer, desc->label, sizeof(info->consumer)); 2342 2343 /* 2344 * Userspace only need to know that the kernel is using this GPIO so 2345 * it can't use it. 2346 */ 2347 info->flags = 0; 2348 if (test_bit(FLAG_REQUESTED, &desc->flags) || 2349 test_bit(FLAG_IS_HOGGED, &desc->flags) || 2350 test_bit(FLAG_USED_AS_IRQ, &desc->flags) || 2351 test_bit(FLAG_EXPORT, &desc->flags) || 2352 test_bit(FLAG_SYSFS, &desc->flags) || 2353 !gpiochip_line_is_valid(gc, info->offset) || 2354 !ok_for_pinctrl) 2355 info->flags |= GPIO_V2_LINE_FLAG_USED; 2356 2357 if (test_bit(FLAG_IS_OUT, &desc->flags)) 2358 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT; 2359 else 2360 info->flags |= GPIO_V2_LINE_FLAG_INPUT; 2361 2362 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) 2363 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW; 2364 2365 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) 2366 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN; 2367 if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) 2368 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE; 2369 2370 if (test_bit(FLAG_BIAS_DISABLE, &desc->flags)) 2371 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED; 2372 if (test_bit(FLAG_PULL_DOWN, &desc->flags)) 2373 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN; 2374 if (test_bit(FLAG_PULL_UP, &desc->flags)) 2375 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP; 2376 2377 if (test_bit(FLAG_EDGE_RISING, &desc->flags)) 2378 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING; 2379 if (test_bit(FLAG_EDGE_FALLING, &desc->flags)) 2380 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING; 2381 2382 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &desc->flags)) 2383 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME; 2384 else if (test_bit(FLAG_EVENT_CLOCK_HTE, &desc->flags)) 2385 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE; 2386 2387 debounce_period_us = READ_ONCE(desc->debounce_period_us); 2388 if (debounce_period_us) { 2389 info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; 2390 info->attrs[num_attrs].debounce_period_us = debounce_period_us; 2391 num_attrs++; 2392 } 2393 info->num_attrs = num_attrs; 2394 2395 spin_unlock_irqrestore(&gpio_lock, flags); 2396 } 2397 2398 struct gpio_chardev_data { 2399 struct gpio_device *gdev; 2400 wait_queue_head_t wait; 2401 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32); 2402 struct notifier_block lineinfo_changed_nb; 2403 struct notifier_block device_unregistered_nb; 2404 unsigned long *watched_lines; 2405 #ifdef CONFIG_GPIO_CDEV_V1 2406 atomic_t watch_abi_version; 2407 #endif 2408 }; 2409 2410 static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip) 2411 { 2412 struct gpio_device *gdev = cdev->gdev; 2413 struct gpiochip_info chipinfo; 2414 2415 memset(&chipinfo, 0, sizeof(chipinfo)); 2416 2417 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name)); 2418 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label)); 2419 chipinfo.lines = gdev->ngpio; 2420 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo))) 2421 return -EFAULT; 2422 return 0; 2423 } 2424 2425 #ifdef CONFIG_GPIO_CDEV_V1 2426 /* 2427 * returns 0 if the versions match, else the previously selected ABI version 2428 */ 2429 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata, 2430 unsigned int version) 2431 { 2432 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version); 2433 2434 if (abiv == version) 2435 return 0; 2436 2437 return abiv; 2438 } 2439 2440 static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip, 2441 bool watch) 2442 { 2443 struct gpio_desc *desc; 2444 struct gpioline_info lineinfo; 2445 struct gpio_v2_line_info lineinfo_v2; 2446 2447 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2448 return -EFAULT; 2449 2450 /* this doubles as a range check on line_offset */ 2451 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset); 2452 if (IS_ERR(desc)) 2453 return PTR_ERR(desc); 2454 2455 if (watch) { 2456 if (lineinfo_ensure_abi_version(cdev, 1)) 2457 return -EPERM; 2458 2459 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines)) 2460 return -EBUSY; 2461 } 2462 2463 gpio_desc_to_lineinfo(desc, &lineinfo_v2); 2464 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); 2465 2466 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2467 if (watch) 2468 clear_bit(lineinfo.line_offset, cdev->watched_lines); 2469 return -EFAULT; 2470 } 2471 2472 return 0; 2473 } 2474 #endif 2475 2476 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, 2477 bool watch) 2478 { 2479 struct gpio_desc *desc; 2480 struct gpio_v2_line_info lineinfo; 2481 2482 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2483 return -EFAULT; 2484 2485 if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding))) 2486 return -EINVAL; 2487 2488 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset); 2489 if (IS_ERR(desc)) 2490 return PTR_ERR(desc); 2491 2492 if (watch) { 2493 #ifdef CONFIG_GPIO_CDEV_V1 2494 if (lineinfo_ensure_abi_version(cdev, 2)) 2495 return -EPERM; 2496 #endif 2497 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines)) 2498 return -EBUSY; 2499 } 2500 gpio_desc_to_lineinfo(desc, &lineinfo); 2501 2502 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2503 if (watch) 2504 clear_bit(lineinfo.offset, cdev->watched_lines); 2505 return -EFAULT; 2506 } 2507 2508 return 0; 2509 } 2510 2511 static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip) 2512 { 2513 __u32 offset; 2514 2515 if (copy_from_user(&offset, ip, sizeof(offset))) 2516 return -EFAULT; 2517 2518 if (offset >= cdev->gdev->ngpio) 2519 return -EINVAL; 2520 2521 if (!test_and_clear_bit(offset, cdev->watched_lines)) 2522 return -EBUSY; 2523 2524 return 0; 2525 } 2526 2527 static long gpio_ioctl_unlocked(struct file *file, unsigned int cmd, unsigned long arg) 2528 { 2529 struct gpio_chardev_data *cdev = file->private_data; 2530 struct gpio_device *gdev = cdev->gdev; 2531 void __user *ip = (void __user *)arg; 2532 2533 /* We fail any subsequent ioctl():s when the chip is gone */ 2534 if (!gdev->chip) 2535 return -ENODEV; 2536 2537 /* Fill in the struct and pass to userspace */ 2538 switch (cmd) { 2539 case GPIO_GET_CHIPINFO_IOCTL: 2540 return chipinfo_get(cdev, ip); 2541 #ifdef CONFIG_GPIO_CDEV_V1 2542 case GPIO_GET_LINEHANDLE_IOCTL: 2543 return linehandle_create(gdev, ip); 2544 case GPIO_GET_LINEEVENT_IOCTL: 2545 return lineevent_create(gdev, ip); 2546 case GPIO_GET_LINEINFO_IOCTL: 2547 return lineinfo_get_v1(cdev, ip, false); 2548 case GPIO_GET_LINEINFO_WATCH_IOCTL: 2549 return lineinfo_get_v1(cdev, ip, true); 2550 #endif /* CONFIG_GPIO_CDEV_V1 */ 2551 case GPIO_V2_GET_LINEINFO_IOCTL: 2552 return lineinfo_get(cdev, ip, false); 2553 case GPIO_V2_GET_LINEINFO_WATCH_IOCTL: 2554 return lineinfo_get(cdev, ip, true); 2555 case GPIO_V2_GET_LINE_IOCTL: 2556 return linereq_create(gdev, ip); 2557 case GPIO_GET_LINEINFO_UNWATCH_IOCTL: 2558 return lineinfo_unwatch(cdev, ip); 2559 default: 2560 return -EINVAL; 2561 } 2562 } 2563 2564 /* 2565 * gpio_ioctl() - ioctl handler for the GPIO chardev 2566 */ 2567 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 2568 { 2569 struct gpio_chardev_data *cdev = file->private_data; 2570 2571 return call_ioctl_locked(file, cmd, arg, cdev->gdev, 2572 gpio_ioctl_unlocked); 2573 } 2574 2575 #ifdef CONFIG_COMPAT 2576 static long gpio_ioctl_compat(struct file *file, unsigned int cmd, 2577 unsigned long arg) 2578 { 2579 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 2580 } 2581 #endif 2582 2583 static int lineinfo_changed_notify(struct notifier_block *nb, 2584 unsigned long action, void *data) 2585 { 2586 struct gpio_chardev_data *cdev = 2587 container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb); 2588 struct gpio_v2_line_info_changed chg; 2589 struct gpio_desc *desc = data; 2590 int ret; 2591 2592 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines)) 2593 return NOTIFY_DONE; 2594 2595 memset(&chg, 0, sizeof(chg)); 2596 chg.event_type = action; 2597 chg.timestamp_ns = ktime_get_ns(); 2598 gpio_desc_to_lineinfo(desc, &chg.info); 2599 2600 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock); 2601 if (ret) 2602 wake_up_poll(&cdev->wait, EPOLLIN); 2603 else 2604 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n"); 2605 2606 return NOTIFY_OK; 2607 } 2608 2609 static int gpio_device_unregistered_notify(struct notifier_block *nb, 2610 unsigned long action, void *data) 2611 { 2612 struct gpio_chardev_data *cdev = container_of(nb, 2613 struct gpio_chardev_data, 2614 device_unregistered_nb); 2615 2616 wake_up_poll(&cdev->wait, EPOLLIN | EPOLLERR); 2617 2618 return NOTIFY_OK; 2619 } 2620 2621 static __poll_t lineinfo_watch_poll_unlocked(struct file *file, 2622 struct poll_table_struct *pollt) 2623 { 2624 struct gpio_chardev_data *cdev = file->private_data; 2625 __poll_t events = 0; 2626 2627 if (!cdev->gdev->chip) 2628 return EPOLLHUP | EPOLLERR; 2629 2630 poll_wait(file, &cdev->wait, pollt); 2631 2632 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events, 2633 &cdev->wait.lock)) 2634 events = EPOLLIN | EPOLLRDNORM; 2635 2636 return events; 2637 } 2638 2639 static __poll_t lineinfo_watch_poll(struct file *file, 2640 struct poll_table_struct *pollt) 2641 { 2642 struct gpio_chardev_data *cdev = file->private_data; 2643 2644 return call_poll_locked(file, pollt, cdev->gdev, 2645 lineinfo_watch_poll_unlocked); 2646 } 2647 2648 static ssize_t lineinfo_watch_read_unlocked(struct file *file, char __user *buf, 2649 size_t count, loff_t *off) 2650 { 2651 struct gpio_chardev_data *cdev = file->private_data; 2652 struct gpio_v2_line_info_changed event; 2653 ssize_t bytes_read = 0; 2654 int ret; 2655 size_t event_size; 2656 2657 if (!cdev->gdev->chip) 2658 return -ENODEV; 2659 2660 #ifndef CONFIG_GPIO_CDEV_V1 2661 event_size = sizeof(struct gpio_v2_line_info_changed); 2662 if (count < event_size) 2663 return -EINVAL; 2664 #endif 2665 2666 do { 2667 spin_lock(&cdev->wait.lock); 2668 if (kfifo_is_empty(&cdev->events)) { 2669 if (bytes_read) { 2670 spin_unlock(&cdev->wait.lock); 2671 return bytes_read; 2672 } 2673 2674 if (file->f_flags & O_NONBLOCK) { 2675 spin_unlock(&cdev->wait.lock); 2676 return -EAGAIN; 2677 } 2678 2679 ret = wait_event_interruptible_locked(cdev->wait, 2680 !kfifo_is_empty(&cdev->events)); 2681 if (ret) { 2682 spin_unlock(&cdev->wait.lock); 2683 return ret; 2684 } 2685 } 2686 #ifdef CONFIG_GPIO_CDEV_V1 2687 /* must be after kfifo check so watch_abi_version is set */ 2688 if (atomic_read(&cdev->watch_abi_version) == 2) 2689 event_size = sizeof(struct gpio_v2_line_info_changed); 2690 else 2691 event_size = sizeof(struct gpioline_info_changed); 2692 if (count < event_size) { 2693 spin_unlock(&cdev->wait.lock); 2694 return -EINVAL; 2695 } 2696 #endif 2697 ret = kfifo_out(&cdev->events, &event, 1); 2698 spin_unlock(&cdev->wait.lock); 2699 if (ret != 1) { 2700 ret = -EIO; 2701 break; 2702 /* We should never get here. See lineevent_read(). */ 2703 } 2704 2705 #ifdef CONFIG_GPIO_CDEV_V1 2706 if (event_size == sizeof(struct gpio_v2_line_info_changed)) { 2707 if (copy_to_user(buf + bytes_read, &event, event_size)) 2708 return -EFAULT; 2709 } else { 2710 struct gpioline_info_changed event_v1; 2711 2712 gpio_v2_line_info_changed_to_v1(&event, &event_v1); 2713 if (copy_to_user(buf + bytes_read, &event_v1, 2714 event_size)) 2715 return -EFAULT; 2716 } 2717 #else 2718 if (copy_to_user(buf + bytes_read, &event, event_size)) 2719 return -EFAULT; 2720 #endif 2721 bytes_read += event_size; 2722 } while (count >= bytes_read + sizeof(event)); 2723 2724 return bytes_read; 2725 } 2726 2727 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, 2728 size_t count, loff_t *off) 2729 { 2730 struct gpio_chardev_data *cdev = file->private_data; 2731 2732 return call_read_locked(file, buf, count, off, cdev->gdev, 2733 lineinfo_watch_read_unlocked); 2734 } 2735 2736 /** 2737 * gpio_chrdev_open() - open the chardev for ioctl operations 2738 * @inode: inode for this chardev 2739 * @file: file struct for storing private data 2740 * Returns 0 on success 2741 */ 2742 static int gpio_chrdev_open(struct inode *inode, struct file *file) 2743 { 2744 struct gpio_device *gdev = container_of(inode->i_cdev, 2745 struct gpio_device, chrdev); 2746 struct gpio_chardev_data *cdev; 2747 int ret = -ENOMEM; 2748 2749 down_read(&gdev->sem); 2750 2751 /* Fail on open if the backing gpiochip is gone */ 2752 if (!gdev->chip) { 2753 ret = -ENODEV; 2754 goto out_unlock; 2755 } 2756 2757 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL); 2758 if (!cdev) 2759 goto out_unlock; 2760 2761 cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL); 2762 if (!cdev->watched_lines) 2763 goto out_free_cdev; 2764 2765 init_waitqueue_head(&cdev->wait); 2766 INIT_KFIFO(cdev->events); 2767 cdev->gdev = gpio_device_get(gdev); 2768 2769 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify; 2770 ret = blocking_notifier_chain_register(&gdev->line_state_notifier, 2771 &cdev->lineinfo_changed_nb); 2772 if (ret) 2773 goto out_free_bitmap; 2774 2775 cdev->device_unregistered_nb.notifier_call = 2776 gpio_device_unregistered_notify; 2777 ret = blocking_notifier_chain_register(&gdev->device_notifier, 2778 &cdev->device_unregistered_nb); 2779 if (ret) 2780 goto out_unregister_line_notifier; 2781 2782 file->private_data = cdev; 2783 2784 ret = nonseekable_open(inode, file); 2785 if (ret) 2786 goto out_unregister_device_notifier; 2787 2788 up_read(&gdev->sem); 2789 2790 return ret; 2791 2792 out_unregister_device_notifier: 2793 blocking_notifier_chain_unregister(&gdev->device_notifier, 2794 &cdev->device_unregistered_nb); 2795 out_unregister_line_notifier: 2796 blocking_notifier_chain_unregister(&gdev->line_state_notifier, 2797 &cdev->lineinfo_changed_nb); 2798 out_free_bitmap: 2799 gpio_device_put(gdev); 2800 bitmap_free(cdev->watched_lines); 2801 out_free_cdev: 2802 kfree(cdev); 2803 out_unlock: 2804 up_read(&gdev->sem); 2805 return ret; 2806 } 2807 2808 /** 2809 * gpio_chrdev_release() - close chardev after ioctl operations 2810 * @inode: inode for this chardev 2811 * @file: file struct for storing private data 2812 * Returns 0 on success 2813 */ 2814 static int gpio_chrdev_release(struct inode *inode, struct file *file) 2815 { 2816 struct gpio_chardev_data *cdev = file->private_data; 2817 struct gpio_device *gdev = cdev->gdev; 2818 2819 bitmap_free(cdev->watched_lines); 2820 blocking_notifier_chain_unregister(&gdev->device_notifier, 2821 &cdev->device_unregistered_nb); 2822 blocking_notifier_chain_unregister(&gdev->line_state_notifier, 2823 &cdev->lineinfo_changed_nb); 2824 gpio_device_put(gdev); 2825 kfree(cdev); 2826 2827 return 0; 2828 } 2829 2830 static const struct file_operations gpio_fileops = { 2831 .release = gpio_chrdev_release, 2832 .open = gpio_chrdev_open, 2833 .poll = lineinfo_watch_poll, 2834 .read = lineinfo_watch_read, 2835 .owner = THIS_MODULE, 2836 .llseek = no_llseek, 2837 .unlocked_ioctl = gpio_ioctl, 2838 #ifdef CONFIG_COMPAT 2839 .compat_ioctl = gpio_ioctl_compat, 2840 #endif 2841 }; 2842 2843 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt) 2844 { 2845 int ret; 2846 2847 cdev_init(&gdev->chrdev, &gpio_fileops); 2848 gdev->chrdev.owner = THIS_MODULE; 2849 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id); 2850 2851 ret = cdev_device_add(&gdev->chrdev, &gdev->dev); 2852 if (ret) 2853 return ret; 2854 2855 chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n", 2856 MAJOR(devt), gdev->id); 2857 2858 return 0; 2859 } 2860 2861 void gpiolib_cdev_unregister(struct gpio_device *gdev) 2862 { 2863 cdev_device_del(&gdev->chrdev, &gdev->dev); 2864 blocking_notifier_call_chain(&gdev->device_notifier, 0, NULL); 2865 } 2866