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gpiolib-cdev.c
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linux-6.19.14/drivers/gpio/gpiolib-cdev.c
1// SPDX-License-Identifier: GPL-2.0 2 3#include <linux/anon_inodes.h> 4#include <linux/atomic.h> 5#include <linux/bitmap.h> 6#include <linux/build_bug.h> 7#include <linux/cdev.h> 8#include <linux/cleanup.h> 9#include <linux/compat.h> 10#include <linux/compiler.h> 11#include <linux/device.h> 12#include <linux/err.h> 13#include <linux/file.h> 14#include <linux/gpio.h> 15#include <linux/gpio/driver.h> 16#include <linux/hte.h> 17#include <linux/interrupt.h> 18#include <linux/irqreturn.h> 19#include <linux/kfifo.h> 20#include <linux/module.h> 21#include <linux/mutex.h> 22#include <linux/overflow.h> 23#include <linux/pinctrl/consumer.h> 24#include <linux/poll.h> 25#include <linux/seq_file.h> 26#include <linux/spinlock.h> 27#include <linux/string.h> 28#include <linux/timekeeping.h> 29#include <linux/uaccess.h> 30#include <linux/workqueue.h> 31 32#include <uapi/linux/gpio.h> 33 34#include "gpiolib.h" 35#include "gpiolib-cdev.h" 36 37/* 38 * Array sizes must ensure 64-bit alignment and not create holes in the 39 * struct packing. 40 */ 41static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2)); 42static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8)); 43 44/* 45 * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility 46 */ 47static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8)); 48static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8)); 49static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8)); 50static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8)); 51static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8)); 52static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8)); 53static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8)); 54static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8)); 55 56/* Character device interface to GPIO. 57 * 58 * The GPIO character device, /dev/gpiochipN, provides userspace an 59 * interface to gpiolib GPIOs via ioctl()s. 60 */ 61 62/* 63 * GPIO line handle management 64 */ 65 66#ifdef CONFIG_GPIO_CDEV_V1 67/** 68 * struct linehandle_state - contains the state of a userspace handle 69 * @gdev: the GPIO device the handle pertains to 70 * @label: consumer label used to tag descriptors 71 * @descs: the GPIO descriptors held by this handle 72 * @num_descs: the number of descriptors held in the descs array 73 */ 74struct linehandle_state { 75 struct gpio_device *gdev; 76 const char *label; 77 struct gpio_desc *descs[GPIOHANDLES_MAX]; 78 u32 num_descs; 79}; 80 81#define GPIOHANDLE_REQUEST_VALID_FLAGS \ 82 (GPIOHANDLE_REQUEST_INPUT | \ 83 GPIOHANDLE_REQUEST_OUTPUT | \ 84 GPIOHANDLE_REQUEST_ACTIVE_LOW | \ 85 GPIOHANDLE_REQUEST_BIAS_PULL_UP | \ 86 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \ 87 GPIOHANDLE_REQUEST_BIAS_DISABLE | \ 88 GPIOHANDLE_REQUEST_OPEN_DRAIN | \ 89 GPIOHANDLE_REQUEST_OPEN_SOURCE) 90 91#define GPIOHANDLE_REQUEST_DIRECTION_FLAGS \ 92 (GPIOHANDLE_REQUEST_INPUT | \ 93 GPIOHANDLE_REQUEST_OUTPUT) 94 95static int linehandle_validate_flags(u32 flags) 96{ 97 /* Return an error if an unknown flag is set */ 98 if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) 99 return -EINVAL; 100 101 /* 102 * Do not allow both INPUT & OUTPUT flags to be set as they are 103 * contradictory. 104 */ 105 if ((flags & GPIOHANDLE_REQUEST_INPUT) && 106 (flags & GPIOHANDLE_REQUEST_OUTPUT)) 107 return -EINVAL; 108 109 /* 110 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If 111 * the hardware actually supports enabling both at the same time the 112 * electrical result would be disastrous. 113 */ 114 if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) && 115 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 116 return -EINVAL; 117 118 /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */ 119 if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) && 120 ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 121 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))) 122 return -EINVAL; 123 124 /* Bias flags only allowed for input or output mode. */ 125 if (!((flags & GPIOHANDLE_REQUEST_INPUT) || 126 (flags & GPIOHANDLE_REQUEST_OUTPUT)) && 127 ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) || 128 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) || 129 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN))) 130 return -EINVAL; 131 132 /* Only one bias flag can be set. */ 133 if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 134 (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 135 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 136 ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 137 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 138 return -EINVAL; 139 140 return 0; 141} 142 143static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp) 144{ 145 unsigned long flags = READ_ONCE(*flagsp); 146 147 assign_bit(GPIOD_FLAG_ACTIVE_LOW, &flags, 148 lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW); 149 assign_bit(GPIOD_FLAG_OPEN_DRAIN, &flags, 150 lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN); 151 assign_bit(GPIOD_FLAG_OPEN_SOURCE, &flags, 152 lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE); 153 assign_bit(GPIOD_FLAG_PULL_UP, &flags, 154 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP); 155 assign_bit(GPIOD_FLAG_PULL_DOWN, &flags, 156 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN); 157 assign_bit(GPIOD_FLAG_BIAS_DISABLE, &flags, 158 lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE); 159 160 WRITE_ONCE(*flagsp, flags); 161} 162 163static long linehandle_set_config(struct linehandle_state *lh, 164 void __user *ip) 165{ 166 struct gpiohandle_config gcnf; 167 struct gpio_desc *desc; 168 int i, ret; 169 u32 lflags; 170 171 if (copy_from_user(&gcnf, ip, sizeof(gcnf))) 172 return -EFAULT; 173 174 lflags = gcnf.flags; 175 ret = linehandle_validate_flags(lflags); 176 if (ret) 177 return ret; 178 179 /* Lines must be reconfigured explicitly as input or output. */ 180 if (!(lflags & GPIOHANDLE_REQUEST_DIRECTION_FLAGS)) 181 return -EINVAL; 182 183 for (i = 0; i < lh->num_descs; i++) { 184 desc = lh->descs[i]; 185 linehandle_flags_to_desc_flags(lflags, &desc->flags); 186 187 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { 188 int val = !!gcnf.default_values[i]; 189 190 ret = gpiod_direction_output_nonotify(desc, val); 191 if (ret) 192 return ret; 193 } else { 194 ret = gpiod_direction_input_nonotify(desc); 195 if (ret) 196 return ret; 197 } 198 199 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG); 200 } 201 return 0; 202} 203 204static long linehandle_ioctl(struct file *file, unsigned int cmd, 205 unsigned long arg) 206{ 207 struct linehandle_state *lh = file->private_data; 208 void __user *ip = (void __user *)arg; 209 struct gpiohandle_data ghd; 210 DECLARE_BITMAP(vals, GPIOHANDLES_MAX); 211 unsigned int i; 212 int ret; 213 214 guard(srcu)(&lh->gdev->srcu); 215 216 if (!rcu_access_pointer(lh->gdev->chip)) 217 return -ENODEV; 218 219 switch (cmd) { 220 case GPIOHANDLE_GET_LINE_VALUES_IOCTL: 221 /* NOTE: It's okay to read values of output lines */ 222 ret = gpiod_get_array_value_complex(false, true, 223 lh->num_descs, lh->descs, 224 NULL, vals); 225 if (ret) 226 return ret; 227 228 memset(&ghd, 0, sizeof(ghd)); 229 for (i = 0; i < lh->num_descs; i++) 230 ghd.values[i] = test_bit(i, vals); 231 232 if (copy_to_user(ip, &ghd, sizeof(ghd))) 233 return -EFAULT; 234 235 return 0; 236 case GPIOHANDLE_SET_LINE_VALUES_IOCTL: 237 /* 238 * All line descriptors were created at once with the same 239 * flags so just check if the first one is really output. 240 */ 241 if (!test_bit(GPIOD_FLAG_IS_OUT, &lh->descs[0]->flags)) 242 return -EPERM; 243 244 if (copy_from_user(&ghd, ip, sizeof(ghd))) 245 return -EFAULT; 246 247 /* Clamp all values to [0,1] */ 248 for (i = 0; i < lh->num_descs; i++) 249 __assign_bit(i, vals, ghd.values[i]); 250 251 /* Reuse the array setting function */ 252 return gpiod_set_array_value_complex(false, 253 true, 254 lh->num_descs, 255 lh->descs, 256 NULL, 257 vals); 258 case GPIOHANDLE_SET_CONFIG_IOCTL: 259 return linehandle_set_config(lh, ip); 260 default: 261 return -EINVAL; 262 } 263} 264 265#ifdef CONFIG_COMPAT 266static long linehandle_ioctl_compat(struct file *file, unsigned int cmd, 267 unsigned long arg) 268{ 269 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 270} 271#endif 272 273static void linehandle_free(struct linehandle_state *lh) 274{ 275 int i; 276 277 for (i = 0; i < lh->num_descs; i++) 278 if (lh->descs[i]) 279 gpiod_free(lh->descs[i]); 280 kfree(lh->label); 281 gpio_device_put(lh->gdev); 282 kfree(lh); 283} 284 285static int linehandle_release(struct inode *inode, struct file *file) 286{ 287 linehandle_free(file->private_data); 288 return 0; 289} 290 291static const struct file_operations linehandle_fileops = { 292 .release = linehandle_release, 293 .owner = THIS_MODULE, 294 .llseek = noop_llseek, 295 .unlocked_ioctl = linehandle_ioctl, 296#ifdef CONFIG_COMPAT 297 .compat_ioctl = linehandle_ioctl_compat, 298#endif 299}; 300 301DEFINE_FREE(linehandle_free, struct linehandle_state *, if (!IS_ERR_OR_NULL(_T)) linehandle_free(_T)) 302 303static int linehandle_create(struct gpio_device *gdev, void __user *ip) 304{ 305 struct gpiohandle_request handlereq; 306 struct linehandle_state *lh __free(linehandle_free) = NULL; 307 int i, ret; 308 u32 lflags; 309 310 if (copy_from_user(&handlereq, ip, sizeof(handlereq))) 311 return -EFAULT; 312 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX)) 313 return -EINVAL; 314 315 lflags = handlereq.flags; 316 317 ret = linehandle_validate_flags(lflags); 318 if (ret) 319 return ret; 320 321 lh = kzalloc(sizeof(*lh), GFP_KERNEL); 322 if (!lh) 323 return -ENOMEM; 324 lh->gdev = gpio_device_get(gdev); 325 326 if (handlereq.consumer_label[0] != '\0') { 327 /* label is only initialized if consumer_label is set */ 328 lh->label = kstrndup(handlereq.consumer_label, 329 sizeof(handlereq.consumer_label) - 1, 330 GFP_KERNEL); 331 if (!lh->label) 332 return -ENOMEM; 333 } 334 335 lh->num_descs = handlereq.lines; 336 337 /* Request each GPIO */ 338 for (i = 0; i < handlereq.lines; i++) { 339 u32 offset = handlereq.lineoffsets[i]; 340 struct gpio_desc *desc = gpio_device_get_desc(gdev, offset); 341 342 if (IS_ERR(desc)) 343 return PTR_ERR(desc); 344 345 ret = gpiod_request_user(desc, lh->label); 346 if (ret) 347 return ret; 348 lh->descs[i] = desc; 349 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags); 350 351 ret = gpiod_set_transitory(desc, false); 352 if (ret < 0) 353 return ret; 354 355 /* 356 * Lines have to be requested explicitly for input 357 * or output, else the line will be treated "as is". 358 */ 359 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { 360 int val = !!handlereq.default_values[i]; 361 362 ret = gpiod_direction_output_nonotify(desc, val); 363 if (ret) 364 return ret; 365 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { 366 ret = gpiod_direction_input_nonotify(desc); 367 if (ret) 368 return ret; 369 } 370 371 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED); 372 373 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 374 offset); 375 } 376 377 FD_PREPARE(fdf, O_RDONLY | O_CLOEXEC, 378 anon_inode_getfile("gpio-linehandle", &linehandle_fileops, 379 lh, O_RDONLY | O_CLOEXEC)); 380 if (fdf.err) 381 return fdf.err; 382 retain_and_null_ptr(lh); 383 384 handlereq.fd = fd_prepare_fd(fdf); 385 if (copy_to_user(ip, &handlereq, sizeof(handlereq))) 386 return -EFAULT; 387 388 fd_publish(fdf); 389 390 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 391 handlereq.lines); 392 393 return 0; 394} 395#endif /* CONFIG_GPIO_CDEV_V1 */ 396 397/** 398 * struct line - contains the state of a requested line 399 * @desc: the GPIO descriptor for this line. 400 * @req: the corresponding line request 401 * @irq: the interrupt triggered in response to events on this GPIO 402 * @edflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or 403 * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied 404 * @timestamp_ns: cache for the timestamp storing it between hardirq and 405 * IRQ thread, used to bring the timestamp close to the actual event 406 * @req_seqno: the seqno for the current edge event in the sequence of 407 * events for the corresponding line request. This is drawn from the @req. 408 * @line_seqno: the seqno for the current edge event in the sequence of 409 * events for this line. 410 * @work: the worker that implements software debouncing 411 * @sw_debounced: flag indicating if the software debouncer is active 412 * @level: the current debounced physical level of the line 413 * @hdesc: the Hardware Timestamp Engine (HTE) descriptor 414 * @raw_level: the line level at the time of event 415 * @total_discard_seq: the running counter of the discarded events 416 * @last_seqno: the last sequence number before debounce period expires 417 */ 418struct line { 419 struct gpio_desc *desc; 420 /* 421 * -- edge detector specific fields -- 422 */ 423 struct linereq *req; 424 unsigned int irq; 425 /* 426 * The flags for the active edge detector configuration. 427 * 428 * edflags is set by linereq_create(), linereq_free(), and 429 * linereq_set_config(), which are themselves mutually 430 * exclusive, and is accessed by edge_irq_thread(), 431 * process_hw_ts_thread() and debounce_work_func(), 432 * which can all live with a slightly stale value. 433 */ 434 u64 edflags; 435 /* 436 * timestamp_ns and req_seqno are accessed only by 437 * edge_irq_handler() and edge_irq_thread(), which are themselves 438 * mutually exclusive, so no additional protection is necessary. 439 */ 440 u64 timestamp_ns; 441 u32 req_seqno; 442 /* 443 * line_seqno is accessed by either edge_irq_thread() or 444 * debounce_work_func(), which are themselves mutually exclusive, 445 * so no additional protection is necessary. 446 */ 447 u32 line_seqno; 448 /* 449 * -- debouncer specific fields -- 450 */ 451 struct delayed_work work; 452 /* 453 * sw_debounce is accessed by linereq_set_config(), which is the 454 * only setter, and linereq_get_values(), which can live with a 455 * slightly stale value. 456 */ 457 unsigned int sw_debounced; 458 /* 459 * level is accessed by debounce_work_func(), which is the only 460 * setter, and linereq_get_values() which can live with a slightly 461 * stale value. 462 */ 463 unsigned int level; 464#ifdef CONFIG_HTE 465 struct hte_ts_desc hdesc; 466 /* 467 * HTE provider sets line level at the time of event. The valid 468 * value is 0 or 1 and negative value for an error. 469 */ 470 int raw_level; 471 /* 472 * when sw_debounce is set on HTE enabled line, this is running 473 * counter of the discarded events. 474 */ 475 u32 total_discard_seq; 476 /* 477 * when sw_debounce is set on HTE enabled line, this variable records 478 * last sequence number before debounce period expires. 479 */ 480 u32 last_seqno; 481#endif /* CONFIG_HTE */ 482}; 483 484/** 485 * struct linereq - contains the state of a userspace line request 486 * @gdev: the GPIO device the line request pertains to 487 * @label: consumer label used to tag GPIO descriptors 488 * @num_lines: the number of lines in the lines array 489 * @wait: wait queue that handles blocking reads of events 490 * @device_unregistered_nb: notifier block for receiving gdev unregister events 491 * @event_buffer_size: the number of elements allocated in @events 492 * @events: KFIFO for the GPIO events 493 * @seqno: the sequence number for edge events generated on all lines in 494 * this line request. Note that this is not used when @num_lines is 1, as 495 * the line_seqno is then the same and is cheaper to calculate. 496 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency 497 * of configuration, particularly multi-step accesses to desc flags. 498 * @lines: the lines held by this line request, with @num_lines elements. 499 */ 500struct linereq { 501 struct gpio_device *gdev; 502 const char *label; 503 u32 num_lines; 504 wait_queue_head_t wait; 505 struct notifier_block device_unregistered_nb; 506 u32 event_buffer_size; 507 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event); 508 atomic_t seqno; 509 struct mutex config_mutex; 510 struct line lines[] __counted_by(num_lines); 511}; 512 513#define GPIO_V2_LINE_BIAS_FLAGS \ 514 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \ 515 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \ 516 GPIO_V2_LINE_FLAG_BIAS_DISABLED) 517 518#define GPIO_V2_LINE_DIRECTION_FLAGS \ 519 (GPIO_V2_LINE_FLAG_INPUT | \ 520 GPIO_V2_LINE_FLAG_OUTPUT) 521 522#define GPIO_V2_LINE_DRIVE_FLAGS \ 523 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \ 524 GPIO_V2_LINE_FLAG_OPEN_SOURCE) 525 526#define GPIO_V2_LINE_EDGE_FLAGS \ 527 (GPIO_V2_LINE_FLAG_EDGE_RISING | \ 528 GPIO_V2_LINE_FLAG_EDGE_FALLING) 529 530#define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS 531 532#define GPIO_V2_LINE_VALID_FLAGS \ 533 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ 534 GPIO_V2_LINE_DIRECTION_FLAGS | \ 535 GPIO_V2_LINE_DRIVE_FLAGS | \ 536 GPIO_V2_LINE_EDGE_FLAGS | \ 537 GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \ 538 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \ 539 GPIO_V2_LINE_BIAS_FLAGS) 540 541/* subset of flags relevant for edge detector configuration */ 542#define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \ 543 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ 544 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \ 545 GPIO_V2_LINE_EDGE_FLAGS) 546 547static int linereq_unregistered_notify(struct notifier_block *nb, 548 unsigned long action, void *data) 549{ 550 struct linereq *lr = container_of(nb, struct linereq, 551 device_unregistered_nb); 552 553 wake_up_poll(&lr->wait, EPOLLIN | EPOLLERR); 554 555 return NOTIFY_OK; 556} 557 558static void linereq_put_event(struct linereq *lr, 559 struct gpio_v2_line_event *le) 560{ 561 bool overflow = false; 562 563 scoped_guard(spinlock, &lr->wait.lock) { 564 if (kfifo_is_full(&lr->events)) { 565 overflow = true; 566 kfifo_skip(&lr->events); 567 } 568 kfifo_in(&lr->events, le, 1); 569 } 570 if (!overflow) 571 wake_up_poll(&lr->wait, EPOLLIN); 572 else 573 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 574} 575 576static u64 line_event_timestamp(struct line *line) 577{ 578 if (test_bit(GPIOD_FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags)) 579 return ktime_get_real_ns(); 580 else if (IS_ENABLED(CONFIG_HTE) && 581 test_bit(GPIOD_FLAG_EVENT_CLOCK_HTE, &line->desc->flags)) 582 return line->timestamp_ns; 583 584 return ktime_get_ns(); 585} 586 587static u32 line_event_id(int level) 588{ 589 return level ? GPIO_V2_LINE_EVENT_RISING_EDGE : 590 GPIO_V2_LINE_EVENT_FALLING_EDGE; 591} 592 593static inline char *make_irq_label(const char *orig) 594{ 595 char *new; 596 597 if (!orig) 598 return NULL; 599 600 new = kstrdup_and_replace(orig, '/', ':', GFP_KERNEL); 601 if (!new) 602 return ERR_PTR(-ENOMEM); 603 604 return new; 605} 606 607static inline void free_irq_label(const char *label) 608{ 609 kfree(label); 610} 611 612#ifdef CONFIG_HTE 613 614static enum hte_return process_hw_ts_thread(void *p) 615{ 616 struct line *line; 617 struct linereq *lr; 618 struct gpio_v2_line_event le; 619 u64 edflags; 620 int level; 621 622 if (!p) 623 return HTE_CB_HANDLED; 624 625 line = p; 626 lr = line->req; 627 628 memset(&le, 0, sizeof(le)); 629 630 le.timestamp_ns = line->timestamp_ns; 631 edflags = READ_ONCE(line->edflags); 632 633 switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) { 634 case GPIO_V2_LINE_FLAG_EDGE_BOTH: 635 level = (line->raw_level >= 0) ? 636 line->raw_level : 637 gpiod_get_raw_value_cansleep(line->desc); 638 639 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 640 level = !level; 641 642 le.id = line_event_id(level); 643 break; 644 case GPIO_V2_LINE_FLAG_EDGE_RISING: 645 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 646 break; 647 case GPIO_V2_LINE_FLAG_EDGE_FALLING: 648 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 649 break; 650 default: 651 return HTE_CB_HANDLED; 652 } 653 le.line_seqno = line->line_seqno; 654 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno; 655 le.offset = gpiod_hwgpio(line->desc); 656 657 linereq_put_event(lr, &le); 658 659 return HTE_CB_HANDLED; 660} 661 662static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p) 663{ 664 struct line *line; 665 struct linereq *lr; 666 int diff_seqno = 0; 667 668 if (!ts || !p) 669 return HTE_CB_HANDLED; 670 671 line = p; 672 line->timestamp_ns = ts->tsc; 673 line->raw_level = ts->raw_level; 674 lr = line->req; 675 676 if (READ_ONCE(line->sw_debounced)) { 677 line->total_discard_seq++; 678 line->last_seqno = ts->seq; 679 mod_delayed_work(system_percpu_wq, &line->work, 680 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); 681 } else { 682 if (unlikely(ts->seq < line->line_seqno)) 683 return HTE_CB_HANDLED; 684 685 diff_seqno = ts->seq - line->line_seqno; 686 line->line_seqno = ts->seq; 687 if (lr->num_lines != 1) 688 line->req_seqno = atomic_add_return(diff_seqno, 689 &lr->seqno); 690 691 return HTE_RUN_SECOND_CB; 692 } 693 694 return HTE_CB_HANDLED; 695} 696 697static int hte_edge_setup(struct line *line, u64 eflags) 698{ 699 int ret; 700 unsigned long flags = 0; 701 struct hte_ts_desc *hdesc = &line->hdesc; 702 703 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING) 704 flags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &line->desc->flags) ? 705 HTE_FALLING_EDGE_TS : 706 HTE_RISING_EDGE_TS; 707 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING) 708 flags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &line->desc->flags) ? 709 HTE_RISING_EDGE_TS : 710 HTE_FALLING_EDGE_TS; 711 712 line->total_discard_seq = 0; 713 714 hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL, 715 line->desc); 716 717 ret = hte_ts_get(NULL, hdesc, 0); 718 if (ret) 719 return ret; 720 721 return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread, 722 line); 723} 724 725#else 726 727static int hte_edge_setup(struct line *line, u64 eflags) 728{ 729 return 0; 730} 731#endif /* CONFIG_HTE */ 732 733static irqreturn_t edge_irq_thread(int irq, void *p) 734{ 735 struct line *line = p; 736 struct linereq *lr = line->req; 737 struct gpio_v2_line_event le; 738 739 /* Do not leak kernel stack to userspace */ 740 memset(&le, 0, sizeof(le)); 741 742 if (line->timestamp_ns) { 743 le.timestamp_ns = line->timestamp_ns; 744 } else { 745 /* 746 * We may be running from a nested threaded interrupt in 747 * which case we didn't get the timestamp from 748 * edge_irq_handler(). 749 */ 750 le.timestamp_ns = line_event_timestamp(line); 751 if (lr->num_lines != 1) 752 line->req_seqno = atomic_inc_return(&lr->seqno); 753 } 754 line->timestamp_ns = 0; 755 756 switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) { 757 case GPIO_V2_LINE_FLAG_EDGE_BOTH: 758 le.id = line_event_id(gpiod_get_value_cansleep(line->desc)); 759 break; 760 case GPIO_V2_LINE_FLAG_EDGE_RISING: 761 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 762 break; 763 case GPIO_V2_LINE_FLAG_EDGE_FALLING: 764 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 765 break; 766 default: 767 return IRQ_NONE; 768 } 769 line->line_seqno++; 770 le.line_seqno = line->line_seqno; 771 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno; 772 le.offset = gpiod_hwgpio(line->desc); 773 774 linereq_put_event(lr, &le); 775 776 return IRQ_HANDLED; 777} 778 779static irqreturn_t edge_irq_handler(int irq, void *p) 780{ 781 struct line *line = p; 782 struct linereq *lr = line->req; 783 784 /* 785 * Just store the timestamp in hardirq context so we get it as 786 * close in time as possible to the actual event. 787 */ 788 line->timestamp_ns = line_event_timestamp(line); 789 790 if (lr->num_lines != 1) 791 line->req_seqno = atomic_inc_return(&lr->seqno); 792 793 return IRQ_WAKE_THREAD; 794} 795 796/* 797 * returns the current debounced logical value. 798 */ 799static bool debounced_value(struct line *line) 800{ 801 bool value; 802 803 /* 804 * minor race - debouncer may be stopped here, so edge_detector_stop() 805 * must leave the value unchanged so the following will read the level 806 * from when the debouncer was last running. 807 */ 808 value = READ_ONCE(line->level); 809 810 if (test_bit(GPIOD_FLAG_ACTIVE_LOW, &line->desc->flags)) 811 value = !value; 812 813 return value; 814} 815 816static irqreturn_t debounce_irq_handler(int irq, void *p) 817{ 818 struct line *line = p; 819 820 mod_delayed_work(system_percpu_wq, &line->work, 821 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); 822 823 return IRQ_HANDLED; 824} 825 826static void debounce_work_func(struct work_struct *work) 827{ 828 struct gpio_v2_line_event le; 829 struct line *line = container_of(work, struct line, work.work); 830 struct linereq *lr; 831 u64 eflags, edflags = READ_ONCE(line->edflags); 832 int level = -1; 833#ifdef CONFIG_HTE 834 int diff_seqno; 835 836 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) 837 level = line->raw_level; 838#endif 839 if (level < 0) 840 level = gpiod_get_raw_value_cansleep(line->desc); 841 if (level < 0) { 842 pr_debug_ratelimited("debouncer failed to read line value\n"); 843 return; 844 } 845 846 if (READ_ONCE(line->level) == level) 847 return; 848 849 WRITE_ONCE(line->level, level); 850 851 /* -- edge detection -- */ 852 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS; 853 if (!eflags) 854 return; 855 856 /* switch from physical level to logical - if they differ */ 857 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 858 level = !level; 859 860 /* ignore edges that are not being monitored */ 861 if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) || 862 ((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level)) 863 return; 864 865 /* Do not leak kernel stack to userspace */ 866 memset(&le, 0, sizeof(le)); 867 868 lr = line->req; 869 le.timestamp_ns = line_event_timestamp(line); 870 le.offset = gpiod_hwgpio(line->desc); 871#ifdef CONFIG_HTE 872 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) { 873 /* discard events except the last one */ 874 line->total_discard_seq -= 1; 875 diff_seqno = line->last_seqno - line->total_discard_seq - 876 line->line_seqno; 877 line->line_seqno = line->last_seqno - line->total_discard_seq; 878 le.line_seqno = line->line_seqno; 879 le.seqno = (lr->num_lines == 1) ? 880 le.line_seqno : atomic_add_return(diff_seqno, &lr->seqno); 881 } else 882#endif /* CONFIG_HTE */ 883 { 884 line->line_seqno++; 885 le.line_seqno = line->line_seqno; 886 le.seqno = (lr->num_lines == 1) ? 887 le.line_seqno : atomic_inc_return(&lr->seqno); 888 } 889 890 le.id = line_event_id(level); 891 892 linereq_put_event(lr, &le); 893} 894 895static int debounce_setup(struct line *line, unsigned int debounce_period_us) 896{ 897 unsigned long irqflags; 898 int ret, level, irq; 899 char *label; 900 901 /* 902 * Try hardware. Skip gpiod_set_config() to avoid emitting two 903 * CHANGED_CONFIG line state events. 904 */ 905 ret = gpio_do_set_config(line->desc, 906 pinconf_to_config_packed(PIN_CONFIG_INPUT_DEBOUNCE, 907 debounce_period_us)); 908 if (ret != -ENOTSUPP) 909 return ret; 910 911 if (debounce_period_us) { 912 /* setup software debounce */ 913 level = gpiod_get_raw_value_cansleep(line->desc); 914 if (level < 0) 915 return level; 916 917 if (!(IS_ENABLED(CONFIG_HTE) && 918 test_bit(GPIOD_FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) { 919 irq = gpiod_to_irq(line->desc); 920 if (irq < 0) 921 return -ENXIO; 922 923 label = make_irq_label(line->req->label); 924 if (IS_ERR(label)) 925 return -ENOMEM; 926 927 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING; 928 ret = request_irq(irq, debounce_irq_handler, irqflags, 929 label, line); 930 if (ret) { 931 free_irq_label(label); 932 return ret; 933 } 934 line->irq = irq; 935 } else { 936 ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH); 937 if (ret) 938 return ret; 939 } 940 941 WRITE_ONCE(line->level, level); 942 WRITE_ONCE(line->sw_debounced, 1); 943 } 944 return 0; 945} 946 947static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc, 948 unsigned int line_idx) 949{ 950 unsigned int i; 951 u64 mask = BIT_ULL(line_idx); 952 953 for (i = 0; i < lc->num_attrs; i++) { 954 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 955 (lc->attrs[i].mask & mask)) 956 return true; 957 } 958 return false; 959} 960 961static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc, 962 unsigned int line_idx) 963{ 964 unsigned int i; 965 u64 mask = BIT_ULL(line_idx); 966 967 for (i = 0; i < lc->num_attrs; i++) { 968 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 969 (lc->attrs[i].mask & mask)) 970 return lc->attrs[i].attr.debounce_period_us; 971 } 972 return 0; 973} 974 975static void edge_detector_stop(struct line *line) 976{ 977 if (line->irq) { 978 free_irq_label(free_irq(line->irq, line)); 979 line->irq = 0; 980 } 981 982#ifdef CONFIG_HTE 983 if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) 984 hte_ts_put(&line->hdesc); 985#endif 986 987 cancel_delayed_work_sync(&line->work); 988 WRITE_ONCE(line->sw_debounced, 0); 989 WRITE_ONCE(line->edflags, 0); 990 if (line->desc) 991 WRITE_ONCE(line->desc->debounce_period_us, 0); 992 /* do not change line->level - see comment in debounced_value() */ 993} 994 995static int edge_detector_fifo_init(struct linereq *req) 996{ 997 if (kfifo_initialized(&req->events)) 998 return 0; 999 1000 return kfifo_alloc(&req->events, req->event_buffer_size, GFP_KERNEL); 1001} 1002 1003static int edge_detector_setup(struct line *line, 1004 struct gpio_v2_line_config *lc, 1005 unsigned int line_idx, u64 edflags) 1006{ 1007 u32 debounce_period_us; 1008 unsigned long irqflags = 0; 1009 u64 eflags; 1010 int irq, ret; 1011 char *label; 1012 1013 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS; 1014 if (eflags) { 1015 ret = edge_detector_fifo_init(line->req); 1016 if (ret) 1017 return ret; 1018 } 1019 if (gpio_v2_line_config_debounced(lc, line_idx)) { 1020 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx); 1021 ret = debounce_setup(line, debounce_period_us); 1022 if (ret) 1023 return ret; 1024 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 1025 } 1026 1027 /* detection disabled or sw debouncer will provide edge detection */ 1028 if (!eflags || READ_ONCE(line->sw_debounced)) 1029 return 0; 1030 1031 if (IS_ENABLED(CONFIG_HTE) && 1032 (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1033 return hte_edge_setup(line, edflags); 1034 1035 irq = gpiod_to_irq(line->desc); 1036 if (irq < 0) 1037 return -ENXIO; 1038 1039 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING) 1040 irqflags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &line->desc->flags) ? 1041 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 1042 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING) 1043 irqflags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &line->desc->flags) ? 1044 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 1045 irqflags |= IRQF_ONESHOT; 1046 1047 label = make_irq_label(line->req->label); 1048 if (IS_ERR(label)) 1049 return PTR_ERR(label); 1050 1051 /* Request a thread to read the events */ 1052 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread, 1053 irqflags, label, line); 1054 if (ret) { 1055 free_irq_label(label); 1056 return ret; 1057 } 1058 1059 line->irq = irq; 1060 return 0; 1061} 1062 1063static int edge_detector_update(struct line *line, 1064 struct gpio_v2_line_config *lc, 1065 unsigned int line_idx, u64 edflags) 1066{ 1067 u64 active_edflags = READ_ONCE(line->edflags); 1068 unsigned int debounce_period_us = 1069 gpio_v2_line_config_debounce_period(lc, line_idx); 1070 1071 if ((active_edflags == edflags) && 1072 (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us)) 1073 return 0; 1074 1075 /* sw debounced and still will be...*/ 1076 if (debounce_period_us && READ_ONCE(line->sw_debounced)) { 1077 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); 1078 /* 1079 * ensure event fifo is initialised if edge detection 1080 * is now enabled. 1081 */ 1082 if (edflags & GPIO_V2_LINE_EDGE_FLAGS) 1083 return edge_detector_fifo_init(line->req); 1084 1085 return 0; 1086 } 1087 1088 /* reconfiguring edge detection or sw debounce being disabled */ 1089 if ((line->irq && !READ_ONCE(line->sw_debounced)) || 1090 (active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) || 1091 (!debounce_period_us && READ_ONCE(line->sw_debounced))) 1092 edge_detector_stop(line); 1093 1094 return edge_detector_setup(line, lc, line_idx, edflags); 1095} 1096 1097static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc, 1098 unsigned int line_idx) 1099{ 1100 unsigned int i; 1101 u64 mask = BIT_ULL(line_idx); 1102 1103 for (i = 0; i < lc->num_attrs; i++) { 1104 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) && 1105 (lc->attrs[i].mask & mask)) 1106 return lc->attrs[i].attr.flags; 1107 } 1108 return lc->flags; 1109} 1110 1111static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc, 1112 unsigned int line_idx) 1113{ 1114 unsigned int i; 1115 u64 mask = BIT_ULL(line_idx); 1116 1117 for (i = 0; i < lc->num_attrs; i++) { 1118 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) && 1119 (lc->attrs[i].mask & mask)) 1120 return !!(lc->attrs[i].attr.values & mask); 1121 } 1122 return 0; 1123} 1124 1125static int gpio_v2_line_flags_validate(u64 flags) 1126{ 1127 /* Return an error if an unknown flag is set */ 1128 if (flags & ~GPIO_V2_LINE_VALID_FLAGS) 1129 return -EINVAL; 1130 1131 if (!IS_ENABLED(CONFIG_HTE) && 1132 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1133 return -EOPNOTSUPP; 1134 1135 /* 1136 * Do not allow both INPUT and OUTPUT flags to be set as they are 1137 * contradictory. 1138 */ 1139 if ((flags & GPIO_V2_LINE_FLAG_INPUT) && 1140 (flags & GPIO_V2_LINE_FLAG_OUTPUT)) 1141 return -EINVAL; 1142 1143 /* Only allow one event clock source */ 1144 if (IS_ENABLED(CONFIG_HTE) && 1145 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME) && 1146 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1147 return -EINVAL; 1148 1149 /* Edge detection requires explicit input. */ 1150 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) && 1151 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 1152 return -EINVAL; 1153 1154 /* 1155 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single 1156 * request. If the hardware actually supports enabling both at the 1157 * same time the electrical result would be disastrous. 1158 */ 1159 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) && 1160 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE)) 1161 return -EINVAL; 1162 1163 /* Drive requires explicit output direction. */ 1164 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) && 1165 !(flags & GPIO_V2_LINE_FLAG_OUTPUT)) 1166 return -EINVAL; 1167 1168 /* Bias requires explicit direction. */ 1169 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) && 1170 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS)) 1171 return -EINVAL; 1172 1173 /* Only one bias flag can be set. */ 1174 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) && 1175 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | 1176 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) || 1177 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) && 1178 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) 1179 return -EINVAL; 1180 1181 return 0; 1182} 1183 1184static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc, 1185 unsigned int num_lines) 1186{ 1187 unsigned int i; 1188 u64 flags; 1189 int ret; 1190 1191 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX) 1192 return -EINVAL; 1193 1194 if (!mem_is_zero(lc->padding, sizeof(lc->padding))) 1195 return -EINVAL; 1196 1197 for (i = 0; i < num_lines; i++) { 1198 flags = gpio_v2_line_config_flags(lc, i); 1199 ret = gpio_v2_line_flags_validate(flags); 1200 if (ret) 1201 return ret; 1202 1203 /* debounce requires explicit input */ 1204 if (gpio_v2_line_config_debounced(lc, i) && 1205 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 1206 return -EINVAL; 1207 } 1208 return 0; 1209} 1210 1211static void gpio_v2_line_config_flags_to_desc_flags(u64 lflags, 1212 unsigned long *flagsp) 1213{ 1214 unsigned long flags = READ_ONCE(*flagsp); 1215 1216 assign_bit(GPIOD_FLAG_ACTIVE_LOW, &flags, 1217 lflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW); 1218 1219 if (lflags & GPIO_V2_LINE_FLAG_OUTPUT) 1220 set_bit(GPIOD_FLAG_IS_OUT, &flags); 1221 else if (lflags & GPIO_V2_LINE_FLAG_INPUT) 1222 clear_bit(GPIOD_FLAG_IS_OUT, &flags); 1223 1224 assign_bit(GPIOD_FLAG_EDGE_RISING, &flags, 1225 lflags & GPIO_V2_LINE_FLAG_EDGE_RISING); 1226 assign_bit(GPIOD_FLAG_EDGE_FALLING, &flags, 1227 lflags & GPIO_V2_LINE_FLAG_EDGE_FALLING); 1228 1229 assign_bit(GPIOD_FLAG_OPEN_DRAIN, &flags, 1230 lflags & GPIO_V2_LINE_FLAG_OPEN_DRAIN); 1231 assign_bit(GPIOD_FLAG_OPEN_SOURCE, &flags, 1232 lflags & GPIO_V2_LINE_FLAG_OPEN_SOURCE); 1233 1234 assign_bit(GPIOD_FLAG_PULL_UP, &flags, 1235 lflags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP); 1236 assign_bit(GPIOD_FLAG_PULL_DOWN, &flags, 1237 lflags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN); 1238 assign_bit(GPIOD_FLAG_BIAS_DISABLE, &flags, 1239 lflags & GPIO_V2_LINE_FLAG_BIAS_DISABLED); 1240 1241 assign_bit(GPIOD_FLAG_EVENT_CLOCK_REALTIME, &flags, 1242 lflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME); 1243 assign_bit(GPIOD_FLAG_EVENT_CLOCK_HTE, &flags, 1244 lflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE); 1245 1246 WRITE_ONCE(*flagsp, flags); 1247} 1248 1249static long linereq_get_values(struct linereq *lr, void __user *ip) 1250{ 1251 struct gpio_v2_line_values lv; 1252 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1253 struct gpio_desc **descs; 1254 unsigned int i, didx, num_get; 1255 bool val; 1256 int ret; 1257 1258 /* NOTE: It's ok to read values of output lines. */ 1259 if (copy_from_user(&lv, ip, sizeof(lv))) 1260 return -EFAULT; 1261 1262 /* 1263 * gpiod_get_array_value_complex() requires compacted desc and val 1264 * arrays, rather than the sparse ones in lv. 1265 * Calculation of num_get and construction of the desc array is 1266 * optimized to avoid allocation for the desc array for the common 1267 * num_get == 1 case. 1268 */ 1269 /* scan requested lines to calculate the subset to get */ 1270 for (num_get = 0, i = 0; i < lr->num_lines; i++) { 1271 if (lv.mask & BIT_ULL(i)) { 1272 num_get++; 1273 /* capture desc for the num_get == 1 case */ 1274 descs = &lr->lines[i].desc; 1275 } 1276 } 1277 1278 if (num_get == 0) 1279 return -EINVAL; 1280 1281 if (num_get != 1) { 1282 /* build compacted desc array */ 1283 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL); 1284 if (!descs) 1285 return -ENOMEM; 1286 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1287 if (lv.mask & BIT_ULL(i)) { 1288 descs[didx] = lr->lines[i].desc; 1289 didx++; 1290 } 1291 } 1292 } 1293 ret = gpiod_get_array_value_complex(false, true, num_get, 1294 descs, NULL, vals); 1295 1296 if (num_get != 1) 1297 kfree(descs); 1298 if (ret) 1299 return ret; 1300 1301 lv.bits = 0; 1302 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1303 /* unpack compacted vals for the response */ 1304 if (lv.mask & BIT_ULL(i)) { 1305 if (lr->lines[i].sw_debounced) 1306 val = debounced_value(&lr->lines[i]); 1307 else 1308 val = test_bit(didx, vals); 1309 if (val) 1310 lv.bits |= BIT_ULL(i); 1311 didx++; 1312 } 1313 } 1314 1315 if (copy_to_user(ip, &lv, sizeof(lv))) 1316 return -EFAULT; 1317 1318 return 0; 1319} 1320 1321static long linereq_set_values(struct linereq *lr, void __user *ip) 1322{ 1323 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1324 struct gpio_v2_line_values lv; 1325 struct gpio_desc **descs; 1326 unsigned int i, didx, num_set; 1327 int ret; 1328 1329 if (copy_from_user(&lv, ip, sizeof(lv))) 1330 return -EFAULT; 1331 1332 guard(mutex)(&lr->config_mutex); 1333 1334 /* 1335 * gpiod_set_array_value_complex() requires compacted desc and val 1336 * arrays, rather than the sparse ones in lv. 1337 * Calculation of num_set and construction of the descs and vals arrays 1338 * is optimized to minimize scanning the lv->mask, and to avoid 1339 * allocation for the desc array for the common num_set == 1 case. 1340 */ 1341 bitmap_zero(vals, GPIO_V2_LINES_MAX); 1342 /* scan requested lines to determine the subset to be set */ 1343 for (num_set = 0, i = 0; i < lr->num_lines; i++) { 1344 if (lv.mask & BIT_ULL(i)) { 1345 /* add to compacted values */ 1346 if (lv.bits & BIT_ULL(i)) 1347 __set_bit(num_set, vals); 1348 num_set++; 1349 /* capture desc for the num_set == 1 case */ 1350 descs = &lr->lines[i].desc; 1351 } 1352 } 1353 if (num_set == 0) 1354 return -EINVAL; 1355 1356 if (num_set != 1) { 1357 /* build compacted desc array */ 1358 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL); 1359 if (!descs) 1360 return -ENOMEM; 1361 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1362 if (lv.mask & BIT_ULL(i)) { 1363 descs[didx] = lr->lines[i].desc; 1364 didx++; 1365 } 1366 } 1367 } 1368 ret = gpiod_set_array_value_complex(false, true, num_set, 1369 descs, NULL, vals); 1370 1371 if (num_set != 1) 1372 kfree(descs); 1373 return ret; 1374} 1375 1376static long linereq_set_config(struct linereq *lr, void __user *ip) 1377{ 1378 struct gpio_v2_line_config lc; 1379 struct gpio_desc *desc; 1380 struct line *line; 1381 unsigned int i; 1382 u64 flags, edflags; 1383 int ret; 1384 1385 if (copy_from_user(&lc, ip, sizeof(lc))) 1386 return -EFAULT; 1387 1388 ret = gpio_v2_line_config_validate(&lc, lr->num_lines); 1389 if (ret) 1390 return ret; 1391 1392 guard(mutex)(&lr->config_mutex); 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 /* 1399 * Lines not explicitly reconfigured as input or output 1400 * are left unchanged. 1401 */ 1402 if (!(flags & GPIO_V2_LINE_DIRECTION_FLAGS)) 1403 continue; 1404 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1405 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS; 1406 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1407 int val = gpio_v2_line_config_output_value(&lc, i); 1408 1409 edge_detector_stop(line); 1410 ret = gpiod_direction_output_nonotify(desc, val); 1411 if (ret) 1412 return ret; 1413 } else { 1414 ret = gpiod_direction_input_nonotify(desc); 1415 if (ret) 1416 return ret; 1417 1418 ret = edge_detector_update(line, &lc, i, edflags); 1419 if (ret) 1420 return ret; 1421 } 1422 1423 WRITE_ONCE(line->edflags, edflags); 1424 1425 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG); 1426 } 1427 return 0; 1428} 1429 1430static long linereq_ioctl(struct file *file, unsigned int cmd, 1431 unsigned long arg) 1432{ 1433 struct linereq *lr = file->private_data; 1434 void __user *ip = (void __user *)arg; 1435 1436 guard(srcu)(&lr->gdev->srcu); 1437 1438 if (!rcu_access_pointer(lr->gdev->chip)) 1439 return -ENODEV; 1440 1441 switch (cmd) { 1442 case GPIO_V2_LINE_GET_VALUES_IOCTL: 1443 return linereq_get_values(lr, ip); 1444 case GPIO_V2_LINE_SET_VALUES_IOCTL: 1445 return linereq_set_values(lr, ip); 1446 case GPIO_V2_LINE_SET_CONFIG_IOCTL: 1447 return linereq_set_config(lr, ip); 1448 default: 1449 return -EINVAL; 1450 } 1451} 1452 1453#ifdef CONFIG_COMPAT 1454static long linereq_ioctl_compat(struct file *file, unsigned int cmd, 1455 unsigned long arg) 1456{ 1457 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1458} 1459#endif 1460 1461static __poll_t linereq_poll(struct file *file, 1462 struct poll_table_struct *wait) 1463{ 1464 struct linereq *lr = file->private_data; 1465 __poll_t events = 0; 1466 1467 guard(srcu)(&lr->gdev->srcu); 1468 1469 if (!rcu_access_pointer(lr->gdev->chip)) 1470 return EPOLLHUP | EPOLLERR; 1471 1472 poll_wait(file, &lr->wait, wait); 1473 1474 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events, 1475 &lr->wait.lock)) 1476 events = EPOLLIN | EPOLLRDNORM; 1477 1478 return events; 1479} 1480 1481static ssize_t linereq_read(struct file *file, char __user *buf, 1482 size_t count, loff_t *f_ps) 1483{ 1484 struct linereq *lr = file->private_data; 1485 struct gpio_v2_line_event le; 1486 ssize_t bytes_read = 0; 1487 int ret; 1488 1489 guard(srcu)(&lr->gdev->srcu); 1490 1491 if (!rcu_access_pointer(lr->gdev->chip)) 1492 return -ENODEV; 1493 1494 if (count < sizeof(le)) 1495 return -EINVAL; 1496 1497 do { 1498 scoped_guard(spinlock, &lr->wait.lock) { 1499 if (kfifo_is_empty(&lr->events)) { 1500 if (bytes_read) 1501 return bytes_read; 1502 1503 if (file->f_flags & O_NONBLOCK) 1504 return -EAGAIN; 1505 1506 ret = wait_event_interruptible_locked(lr->wait, 1507 !kfifo_is_empty(&lr->events)); 1508 if (ret) 1509 return ret; 1510 } 1511 1512 if (kfifo_out(&lr->events, &le, 1) != 1) { 1513 /* 1514 * This should never happen - we hold the 1515 * lock from the moment we learned the fifo 1516 * is no longer empty until now. 1517 */ 1518 WARN(1, "failed to read from non-empty kfifo"); 1519 return -EIO; 1520 } 1521 } 1522 1523 if (copy_to_user(buf + bytes_read, &le, sizeof(le))) 1524 return -EFAULT; 1525 bytes_read += sizeof(le); 1526 } while (count >= bytes_read + sizeof(le)); 1527 1528 return bytes_read; 1529} 1530 1531static void linereq_free(struct linereq *lr) 1532{ 1533 unsigned int i; 1534 1535 if (lr->device_unregistered_nb.notifier_call) 1536 blocking_notifier_chain_unregister(&lr->gdev->device_notifier, 1537 &lr->device_unregistered_nb); 1538 1539 for (i = 0; i < lr->num_lines; i++) { 1540 if (lr->lines[i].desc) { 1541 edge_detector_stop(&lr->lines[i]); 1542 gpiod_free(lr->lines[i].desc); 1543 } 1544 } 1545 kfifo_free(&lr->events); 1546 kfree(lr->label); 1547 gpio_device_put(lr->gdev); 1548 kvfree(lr); 1549} 1550 1551static int linereq_release(struct inode *inode, struct file *file) 1552{ 1553 struct linereq *lr = file->private_data; 1554 1555 linereq_free(lr); 1556 return 0; 1557} 1558 1559#ifdef CONFIG_PROC_FS 1560static void linereq_show_fdinfo(struct seq_file *out, struct file *file) 1561{ 1562 struct linereq *lr = file->private_data; 1563 struct device *dev = &lr->gdev->dev; 1564 u16 i; 1565 1566 seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev)); 1567 1568 for (i = 0; i < lr->num_lines; i++) 1569 seq_printf(out, "gpio-line:\t%d\n", 1570 gpiod_hwgpio(lr->lines[i].desc)); 1571} 1572#endif 1573 1574static const struct file_operations line_fileops = { 1575 .release = linereq_release, 1576 .read = linereq_read, 1577 .poll = linereq_poll, 1578 .owner = THIS_MODULE, 1579 .llseek = noop_llseek, 1580 .unlocked_ioctl = linereq_ioctl, 1581#ifdef CONFIG_COMPAT 1582 .compat_ioctl = linereq_ioctl_compat, 1583#endif 1584#ifdef CONFIG_PROC_FS 1585 .show_fdinfo = linereq_show_fdinfo, 1586#endif 1587}; 1588 1589static int linereq_create(struct gpio_device *gdev, void __user *ip) 1590{ 1591 struct gpio_v2_line_request ulr; 1592 struct gpio_v2_line_config *lc; 1593 struct linereq *lr; 1594 struct file *file; 1595 u64 flags, edflags; 1596 unsigned int i; 1597 int fd, ret; 1598 1599 if (copy_from_user(&ulr, ip, sizeof(ulr))) 1600 return -EFAULT; 1601 1602 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX)) 1603 return -EINVAL; 1604 1605 if (!mem_is_zero(ulr.padding, sizeof(ulr.padding))) 1606 return -EINVAL; 1607 1608 lc = &ulr.config; 1609 ret = gpio_v2_line_config_validate(lc, ulr.num_lines); 1610 if (ret) 1611 return ret; 1612 1613 lr = kvzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL); 1614 if (!lr) 1615 return -ENOMEM; 1616 lr->num_lines = ulr.num_lines; 1617 1618 lr->gdev = gpio_device_get(gdev); 1619 1620 for (i = 0; i < ulr.num_lines; i++) { 1621 lr->lines[i].req = lr; 1622 WRITE_ONCE(lr->lines[i].sw_debounced, 0); 1623 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func); 1624 } 1625 1626 if (ulr.consumer[0] != '\0') { 1627 /* label is only initialized if consumer is set */ 1628 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1, 1629 GFP_KERNEL); 1630 if (!lr->label) { 1631 ret = -ENOMEM; 1632 goto out_free_linereq; 1633 } 1634 } 1635 1636 mutex_init(&lr->config_mutex); 1637 init_waitqueue_head(&lr->wait); 1638 INIT_KFIFO(lr->events); 1639 lr->event_buffer_size = ulr.event_buffer_size; 1640 if (lr->event_buffer_size == 0) 1641 lr->event_buffer_size = ulr.num_lines * 16; 1642 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16) 1643 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16; 1644 1645 atomic_set(&lr->seqno, 0); 1646 1647 /* Request each GPIO */ 1648 for (i = 0; i < ulr.num_lines; i++) { 1649 u32 offset = ulr.offsets[i]; 1650 struct gpio_desc *desc = gpio_device_get_desc(gdev, offset); 1651 1652 if (IS_ERR(desc)) { 1653 ret = PTR_ERR(desc); 1654 goto out_free_linereq; 1655 } 1656 1657 ret = gpiod_request_user(desc, lr->label); 1658 if (ret) 1659 goto out_free_linereq; 1660 1661 lr->lines[i].desc = desc; 1662 flags = gpio_v2_line_config_flags(lc, i); 1663 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1664 1665 ret = gpiod_set_transitory(desc, false); 1666 if (ret < 0) 1667 goto out_free_linereq; 1668 1669 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS; 1670 /* 1671 * Lines have to be requested explicitly for input 1672 * or output, else the line will be treated "as is". 1673 */ 1674 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1675 int val = gpio_v2_line_config_output_value(lc, i); 1676 1677 ret = gpiod_direction_output_nonotify(desc, val); 1678 if (ret) 1679 goto out_free_linereq; 1680 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1681 ret = gpiod_direction_input_nonotify(desc); 1682 if (ret) 1683 goto out_free_linereq; 1684 1685 ret = edge_detector_setup(&lr->lines[i], lc, i, 1686 edflags); 1687 if (ret) 1688 goto out_free_linereq; 1689 } 1690 1691 lr->lines[i].edflags = edflags; 1692 1693 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED); 1694 1695 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 1696 offset); 1697 } 1698 1699 lr->device_unregistered_nb.notifier_call = linereq_unregistered_notify; 1700 ret = blocking_notifier_chain_register(&gdev->device_notifier, 1701 &lr->device_unregistered_nb); 1702 if (ret) 1703 goto out_free_linereq; 1704 1705 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 1706 if (fd < 0) { 1707 ret = fd; 1708 goto out_free_linereq; 1709 } 1710 1711 file = anon_inode_getfile("gpio-line", &line_fileops, lr, 1712 O_RDONLY | O_CLOEXEC); 1713 if (IS_ERR(file)) { 1714 ret = PTR_ERR(file); 1715 goto out_put_unused_fd; 1716 } 1717 1718 ulr.fd = fd; 1719 if (copy_to_user(ip, &ulr, sizeof(ulr))) { 1720 /* 1721 * fput() will trigger the release() callback, so do not go onto 1722 * the regular error cleanup path here. 1723 */ 1724 fput(file); 1725 put_unused_fd(fd); 1726 return -EFAULT; 1727 } 1728 1729 fd_install(fd, file); 1730 1731 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 1732 lr->num_lines); 1733 1734 return 0; 1735 1736out_put_unused_fd: 1737 put_unused_fd(fd); 1738out_free_linereq: 1739 linereq_free(lr); 1740 return ret; 1741} 1742 1743#ifdef CONFIG_GPIO_CDEV_V1 1744 1745/* 1746 * GPIO line event management 1747 */ 1748 1749/** 1750 * struct lineevent_state - contains the state of a userspace event 1751 * @gdev: the GPIO device the event pertains to 1752 * @label: consumer label used to tag descriptors 1753 * @desc: the GPIO descriptor held by this event 1754 * @eflags: the event flags this line was requested with 1755 * @irq: the interrupt that trigger in response to events on this GPIO 1756 * @wait: wait queue that handles blocking reads of events 1757 * @device_unregistered_nb: notifier block for receiving gdev unregister events 1758 * @events: KFIFO for the GPIO events 1759 * @timestamp: cache for the timestamp storing it between hardirq 1760 * and IRQ thread, used to bring the timestamp close to the actual 1761 * event 1762 */ 1763struct lineevent_state { 1764 struct gpio_device *gdev; 1765 const char *label; 1766 struct gpio_desc *desc; 1767 u32 eflags; 1768 int irq; 1769 wait_queue_head_t wait; 1770 struct notifier_block device_unregistered_nb; 1771 DECLARE_KFIFO(events, struct gpioevent_data, 16); 1772 u64 timestamp; 1773}; 1774 1775#define GPIOEVENT_REQUEST_VALID_FLAGS \ 1776 (GPIOEVENT_REQUEST_RISING_EDGE | \ 1777 GPIOEVENT_REQUEST_FALLING_EDGE) 1778 1779static __poll_t lineevent_poll(struct file *file, 1780 struct poll_table_struct *wait) 1781{ 1782 struct lineevent_state *le = file->private_data; 1783 __poll_t events = 0; 1784 1785 guard(srcu)(&le->gdev->srcu); 1786 1787 if (!rcu_access_pointer(le->gdev->chip)) 1788 return EPOLLHUP | EPOLLERR; 1789 1790 poll_wait(file, &le->wait, wait); 1791 1792 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock)) 1793 events = EPOLLIN | EPOLLRDNORM; 1794 1795 return events; 1796} 1797 1798static int lineevent_unregistered_notify(struct notifier_block *nb, 1799 unsigned long action, void *data) 1800{ 1801 struct lineevent_state *le = container_of(nb, struct lineevent_state, 1802 device_unregistered_nb); 1803 1804 wake_up_poll(&le->wait, EPOLLIN | EPOLLERR); 1805 1806 return NOTIFY_OK; 1807} 1808 1809struct compat_gpioeevent_data { 1810 compat_u64 timestamp; 1811 u32 id; 1812}; 1813 1814static ssize_t lineevent_read(struct file *file, char __user *buf, 1815 size_t count, loff_t *f_ps) 1816{ 1817 struct lineevent_state *le = file->private_data; 1818 struct gpioevent_data ge; 1819 ssize_t bytes_read = 0; 1820 ssize_t ge_size; 1821 int ret; 1822 1823 guard(srcu)(&le->gdev->srcu); 1824 1825 if (!rcu_access_pointer(le->gdev->chip)) 1826 return -ENODEV; 1827 1828 /* 1829 * When compatible system call is being used the struct gpioevent_data, 1830 * in case of at least ia32, has different size due to the alignment 1831 * differences. Because we have first member 64 bits followed by one of 1832 * 32 bits there is no gap between them. The only difference is the 1833 * padding at the end of the data structure. Hence, we calculate the 1834 * actual sizeof() and pass this as an argument to copy_to_user() to 1835 * drop unneeded bytes from the output. 1836 */ 1837 if (compat_need_64bit_alignment_fixup()) 1838 ge_size = sizeof(struct compat_gpioeevent_data); 1839 else 1840 ge_size = sizeof(struct gpioevent_data); 1841 if (count < ge_size) 1842 return -EINVAL; 1843 1844 do { 1845 scoped_guard(spinlock, &le->wait.lock) { 1846 if (kfifo_is_empty(&le->events)) { 1847 if (bytes_read) 1848 return bytes_read; 1849 1850 if (file->f_flags & O_NONBLOCK) 1851 return -EAGAIN; 1852 1853 ret = wait_event_interruptible_locked(le->wait, 1854 !kfifo_is_empty(&le->events)); 1855 if (ret) 1856 return ret; 1857 } 1858 1859 if (kfifo_out(&le->events, &ge, 1) != 1) { 1860 /* 1861 * This should never happen - we hold the 1862 * lock from the moment we learned the fifo 1863 * is no longer empty until now. 1864 */ 1865 WARN(1, "failed to read from non-empty kfifo"); 1866 return -EIO; 1867 } 1868 } 1869 1870 if (copy_to_user(buf + bytes_read, &ge, ge_size)) 1871 return -EFAULT; 1872 bytes_read += ge_size; 1873 } while (count >= bytes_read + ge_size); 1874 1875 return bytes_read; 1876} 1877 1878static void lineevent_free(struct lineevent_state *le) 1879{ 1880 if (le->device_unregistered_nb.notifier_call) 1881 blocking_notifier_chain_unregister(&le->gdev->device_notifier, 1882 &le->device_unregistered_nb); 1883 if (le->irq) 1884 free_irq_label(free_irq(le->irq, le)); 1885 if (le->desc) 1886 gpiod_free(le->desc); 1887 kfree(le->label); 1888 gpio_device_put(le->gdev); 1889 kfree(le); 1890} 1891 1892static int lineevent_release(struct inode *inode, struct file *file) 1893{ 1894 lineevent_free(file->private_data); 1895 return 0; 1896} 1897 1898static long lineevent_ioctl(struct file *file, unsigned int cmd, 1899 unsigned long arg) 1900{ 1901 struct lineevent_state *le = file->private_data; 1902 void __user *ip = (void __user *)arg; 1903 struct gpiohandle_data ghd; 1904 1905 guard(srcu)(&le->gdev->srcu); 1906 1907 if (!rcu_access_pointer(le->gdev->chip)) 1908 return -ENODEV; 1909 1910 /* 1911 * We can get the value for an event line but not set it, 1912 * because it is input by definition. 1913 */ 1914 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { 1915 int val; 1916 1917 memset(&ghd, 0, sizeof(ghd)); 1918 1919 val = gpiod_get_value_cansleep(le->desc); 1920 if (val < 0) 1921 return val; 1922 ghd.values[0] = val; 1923 1924 if (copy_to_user(ip, &ghd, sizeof(ghd))) 1925 return -EFAULT; 1926 1927 return 0; 1928 } 1929 return -EINVAL; 1930} 1931 1932#ifdef CONFIG_COMPAT 1933static long lineevent_ioctl_compat(struct file *file, unsigned int cmd, 1934 unsigned long arg) 1935{ 1936 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1937} 1938#endif 1939 1940static const struct file_operations lineevent_fileops = { 1941 .release = lineevent_release, 1942 .read = lineevent_read, 1943 .poll = lineevent_poll, 1944 .owner = THIS_MODULE, 1945 .llseek = noop_llseek, 1946 .unlocked_ioctl = lineevent_ioctl, 1947#ifdef CONFIG_COMPAT 1948 .compat_ioctl = lineevent_ioctl_compat, 1949#endif 1950}; 1951 1952static irqreturn_t lineevent_irq_thread(int irq, void *p) 1953{ 1954 struct lineevent_state *le = p; 1955 struct gpioevent_data ge; 1956 int ret; 1957 1958 /* Do not leak kernel stack to userspace */ 1959 memset(&ge, 0, sizeof(ge)); 1960 1961 /* 1962 * We may be running from a nested threaded interrupt in which case 1963 * we didn't get the timestamp from lineevent_irq_handler(). 1964 */ 1965 if (!le->timestamp) 1966 ge.timestamp = ktime_get_ns(); 1967 else 1968 ge.timestamp = le->timestamp; 1969 1970 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE 1971 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 1972 int level = gpiod_get_value_cansleep(le->desc); 1973 1974 if (level) 1975 /* Emit low-to-high event */ 1976 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 1977 else 1978 /* Emit high-to-low event */ 1979 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 1980 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) { 1981 /* Emit low-to-high event */ 1982 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 1983 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 1984 /* Emit high-to-low event */ 1985 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 1986 } else { 1987 return IRQ_NONE; 1988 } 1989 1990 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge, 1991 1, &le->wait.lock); 1992 if (ret) 1993 wake_up_poll(&le->wait, EPOLLIN); 1994 else 1995 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 1996 1997 return IRQ_HANDLED; 1998} 1999 2000static irqreturn_t lineevent_irq_handler(int irq, void *p) 2001{ 2002 struct lineevent_state *le = p; 2003 2004 /* 2005 * Just store the timestamp in hardirq context so we get it as 2006 * close in time as possible to the actual event. 2007 */ 2008 le->timestamp = ktime_get_ns(); 2009 2010 return IRQ_WAKE_THREAD; 2011} 2012 2013static int lineevent_create(struct gpio_device *gdev, void __user *ip) 2014{ 2015 struct gpioevent_request eventreq; 2016 struct lineevent_state *le; 2017 struct gpio_desc *desc; 2018 struct file *file; 2019 u32 offset; 2020 u32 lflags; 2021 u32 eflags; 2022 int fd; 2023 int ret; 2024 int irq, irqflags = 0; 2025 char *label; 2026 2027 if (copy_from_user(&eventreq, ip, sizeof(eventreq))) 2028 return -EFAULT; 2029 2030 offset = eventreq.lineoffset; 2031 lflags = eventreq.handleflags; 2032 eflags = eventreq.eventflags; 2033 2034 desc = gpio_device_get_desc(gdev, offset); 2035 if (IS_ERR(desc)) 2036 return PTR_ERR(desc); 2037 2038 /* Return an error if a unknown flag is set */ 2039 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) || 2040 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS)) 2041 return -EINVAL; 2042 2043 /* This is just wrong: we don't look for events on output lines */ 2044 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) || 2045 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 2046 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 2047 return -EINVAL; 2048 2049 /* Only one bias flag can be set. */ 2050 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 2051 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 2052 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 2053 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 2054 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 2055 return -EINVAL; 2056 2057 le = kzalloc(sizeof(*le), GFP_KERNEL); 2058 if (!le) 2059 return -ENOMEM; 2060 le->gdev = gpio_device_get(gdev); 2061 2062 if (eventreq.consumer_label[0] != '\0') { 2063 /* label is only initialized if consumer_label is set */ 2064 le->label = kstrndup(eventreq.consumer_label, 2065 sizeof(eventreq.consumer_label) - 1, 2066 GFP_KERNEL); 2067 if (!le->label) { 2068 ret = -ENOMEM; 2069 goto out_free_le; 2070 } 2071 } 2072 2073 ret = gpiod_request_user(desc, le->label); 2074 if (ret) 2075 goto out_free_le; 2076 le->desc = desc; 2077 le->eflags = eflags; 2078 2079 linehandle_flags_to_desc_flags(lflags, &desc->flags); 2080 2081 ret = gpiod_direction_input(desc); 2082 if (ret) 2083 goto out_free_le; 2084 2085 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED); 2086 2087 irq = gpiod_to_irq(desc); 2088 if (irq <= 0) { 2089 ret = -ENODEV; 2090 goto out_free_le; 2091 } 2092 2093 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE) 2094 irqflags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &desc->flags) ? 2095 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 2096 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE) 2097 irqflags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &desc->flags) ? 2098 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 2099 irqflags |= IRQF_ONESHOT; 2100 2101 INIT_KFIFO(le->events); 2102 init_waitqueue_head(&le->wait); 2103 2104 le->device_unregistered_nb.notifier_call = lineevent_unregistered_notify; 2105 ret = blocking_notifier_chain_register(&gdev->device_notifier, 2106 &le->device_unregistered_nb); 2107 if (ret) 2108 goto out_free_le; 2109 2110 label = make_irq_label(le->label); 2111 if (IS_ERR(label)) { 2112 ret = PTR_ERR(label); 2113 goto out_free_le; 2114 } 2115 2116 /* Request a thread to read the events */ 2117 ret = request_threaded_irq(irq, 2118 lineevent_irq_handler, 2119 lineevent_irq_thread, 2120 irqflags, 2121 label, 2122 le); 2123 if (ret) { 2124 free_irq_label(label); 2125 goto out_free_le; 2126 } 2127 2128 le->irq = irq; 2129 2130 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 2131 if (fd < 0) { 2132 ret = fd; 2133 goto out_free_le; 2134 } 2135 2136 file = anon_inode_getfile("gpio-event", 2137 &lineevent_fileops, 2138 le, 2139 O_RDONLY | O_CLOEXEC); 2140 if (IS_ERR(file)) { 2141 ret = PTR_ERR(file); 2142 goto out_put_unused_fd; 2143 } 2144 2145 eventreq.fd = fd; 2146 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) { 2147 /* 2148 * fput() will trigger the release() callback, so do not go onto 2149 * the regular error cleanup path here. 2150 */ 2151 fput(file); 2152 put_unused_fd(fd); 2153 return -EFAULT; 2154 } 2155 2156 fd_install(fd, file); 2157 2158 return 0; 2159 2160out_put_unused_fd: 2161 put_unused_fd(fd); 2162out_free_le: 2163 lineevent_free(le); 2164 return ret; 2165} 2166 2167static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2, 2168 struct gpioline_info *info_v1) 2169{ 2170 u64 flagsv2 = info_v2->flags; 2171 2172 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name)); 2173 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer)); 2174 info_v1->line_offset = info_v2->offset; 2175 info_v1->flags = 0; 2176 2177 if (flagsv2 & GPIO_V2_LINE_FLAG_USED) 2178 info_v1->flags |= GPIOLINE_FLAG_KERNEL; 2179 2180 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT) 2181 info_v1->flags |= GPIOLINE_FLAG_IS_OUT; 2182 2183 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 2184 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW; 2185 2186 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN) 2187 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN; 2188 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE) 2189 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE; 2190 2191 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP) 2192 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP; 2193 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) 2194 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN; 2195 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED) 2196 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE; 2197} 2198 2199static void gpio_v2_line_info_changed_to_v1( 2200 struct gpio_v2_line_info_changed *lic_v2, 2201 struct gpioline_info_changed *lic_v1) 2202{ 2203 memset(lic_v1, 0, sizeof(*lic_v1)); 2204 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info); 2205 lic_v1->timestamp = lic_v2->timestamp_ns; 2206 lic_v1->event_type = lic_v2->event_type; 2207} 2208 2209#endif /* CONFIG_GPIO_CDEV_V1 */ 2210 2211static void gpio_desc_to_lineinfo(struct gpio_desc *desc, 2212 struct gpio_v2_line_info *info, bool atomic) 2213{ 2214 u32 debounce_period_us; 2215 unsigned long dflags; 2216 const char *label; 2217 2218 CLASS(gpio_chip_guard, guard)(desc); 2219 if (!guard.gc) 2220 return; 2221 2222 memset(info, 0, sizeof(*info)); 2223 info->offset = gpiod_hwgpio(desc); 2224 2225 if (desc->name) 2226 strscpy(info->name, desc->name, sizeof(info->name)); 2227 2228 dflags = READ_ONCE(desc->flags); 2229 2230 scoped_guard(srcu, &desc->gdev->desc_srcu) { 2231 label = gpiod_get_label(desc); 2232 if (label && test_bit(GPIOD_FLAG_REQUESTED, &dflags)) 2233 strscpy(info->consumer, label, 2234 sizeof(info->consumer)); 2235 } 2236 2237 /* 2238 * Userspace only need know that the kernel is using this GPIO so it 2239 * can't use it. 2240 * The calculation of the used flag is slightly racy, as it may read 2241 * desc, gc and pinctrl state without a lock covering all three at 2242 * once. Worst case if the line is in transition and the calculation 2243 * is inconsistent then it looks to the user like they performed the 2244 * read on the other side of the transition - but that can always 2245 * happen. 2246 * The definitive test that a line is available to userspace is to 2247 * request it. 2248 */ 2249 if (test_bit(GPIOD_FLAG_REQUESTED, &dflags) || 2250 test_bit(GPIOD_FLAG_IS_HOGGED, &dflags) || 2251 test_bit(GPIOD_FLAG_EXPORT, &dflags) || 2252 test_bit(GPIOD_FLAG_SYSFS, &dflags) || 2253 !gpiochip_line_is_valid(guard.gc, info->offset)) { 2254 info->flags |= GPIO_V2_LINE_FLAG_USED; 2255 } else if (!atomic) { 2256 if (!pinctrl_gpio_can_use_line(guard.gc, info->offset)) 2257 info->flags |= GPIO_V2_LINE_FLAG_USED; 2258 } 2259 2260 if (test_bit(GPIOD_FLAG_IS_OUT, &dflags)) 2261 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT; 2262 else 2263 info->flags |= GPIO_V2_LINE_FLAG_INPUT; 2264 2265 if (test_bit(GPIOD_FLAG_ACTIVE_LOW, &dflags)) 2266 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW; 2267 2268 if (test_bit(GPIOD_FLAG_OPEN_DRAIN, &dflags)) 2269 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN; 2270 if (test_bit(GPIOD_FLAG_OPEN_SOURCE, &dflags)) 2271 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE; 2272 2273 if (test_bit(GPIOD_FLAG_BIAS_DISABLE, &dflags)) 2274 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED; 2275 if (test_bit(GPIOD_FLAG_PULL_DOWN, &dflags)) 2276 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN; 2277 if (test_bit(GPIOD_FLAG_PULL_UP, &dflags)) 2278 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP; 2279 2280 if (test_bit(GPIOD_FLAG_EDGE_RISING, &dflags)) 2281 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING; 2282 if (test_bit(GPIOD_FLAG_EDGE_FALLING, &dflags)) 2283 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING; 2284 2285 if (test_bit(GPIOD_FLAG_EVENT_CLOCK_REALTIME, &dflags)) 2286 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME; 2287 else if (test_bit(GPIOD_FLAG_EVENT_CLOCK_HTE, &dflags)) 2288 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE; 2289 2290 debounce_period_us = READ_ONCE(desc->debounce_period_us); 2291 if (debounce_period_us) { 2292 info->attrs[info->num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; 2293 info->attrs[info->num_attrs].debounce_period_us = 2294 debounce_period_us; 2295 info->num_attrs++; 2296 } 2297} 2298 2299struct gpio_chardev_data { 2300 struct gpio_device *gdev; 2301 wait_queue_head_t wait; 2302 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32); 2303 struct notifier_block lineinfo_changed_nb; 2304 struct notifier_block device_unregistered_nb; 2305 unsigned long *watched_lines; 2306#ifdef CONFIG_GPIO_CDEV_V1 2307 atomic_t watch_abi_version; 2308#endif 2309 struct file *fp; 2310}; 2311 2312static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip) 2313{ 2314 struct gpio_device *gdev = cdev->gdev; 2315 struct gpiochip_info chipinfo; 2316 2317 memset(&chipinfo, 0, sizeof(chipinfo)); 2318 2319 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name)); 2320 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label)); 2321 chipinfo.lines = gdev->ngpio; 2322 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo))) 2323 return -EFAULT; 2324 return 0; 2325} 2326 2327#ifdef CONFIG_GPIO_CDEV_V1 2328/* 2329 * returns 0 if the versions match, else the previously selected ABI version 2330 */ 2331static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata, 2332 unsigned int version) 2333{ 2334 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version); 2335 2336 if (abiv == version) 2337 return 0; 2338 2339 return abiv; 2340} 2341 2342static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip, 2343 bool watch) 2344{ 2345 struct gpio_desc *desc; 2346 struct gpioline_info lineinfo; 2347 struct gpio_v2_line_info lineinfo_v2; 2348 2349 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2350 return -EFAULT; 2351 2352 /* this doubles as a range check on line_offset */ 2353 desc = gpio_device_get_desc(cdev->gdev, lineinfo.line_offset); 2354 if (IS_ERR(desc)) 2355 return PTR_ERR(desc); 2356 2357 if (watch) { 2358 if (lineinfo_ensure_abi_version(cdev, 1)) 2359 return -EPERM; 2360 2361 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines)) 2362 return -EBUSY; 2363 } 2364 2365 gpio_desc_to_lineinfo(desc, &lineinfo_v2, false); 2366 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); 2367 2368 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2369 if (watch) 2370 clear_bit(lineinfo.line_offset, cdev->watched_lines); 2371 return -EFAULT; 2372 } 2373 2374 return 0; 2375} 2376#endif 2377 2378static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, 2379 bool watch) 2380{ 2381 struct gpio_desc *desc; 2382 struct gpio_v2_line_info lineinfo; 2383 2384 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2385 return -EFAULT; 2386 2387 if (!mem_is_zero(lineinfo.padding, sizeof(lineinfo.padding))) 2388 return -EINVAL; 2389 2390 desc = gpio_device_get_desc(cdev->gdev, lineinfo.offset); 2391 if (IS_ERR(desc)) 2392 return PTR_ERR(desc); 2393 2394 if (watch) { 2395#ifdef CONFIG_GPIO_CDEV_V1 2396 if (lineinfo_ensure_abi_version(cdev, 2)) 2397 return -EPERM; 2398#endif 2399 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines)) 2400 return -EBUSY; 2401 } 2402 gpio_desc_to_lineinfo(desc, &lineinfo, false); 2403 2404 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2405 if (watch) 2406 clear_bit(lineinfo.offset, cdev->watched_lines); 2407 return -EFAULT; 2408 } 2409 2410 return 0; 2411} 2412 2413static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip) 2414{ 2415 __u32 offset; 2416 2417 if (copy_from_user(&offset, ip, sizeof(offset))) 2418 return -EFAULT; 2419 2420 if (offset >= cdev->gdev->ngpio) 2421 return -EINVAL; 2422 2423 if (!test_and_clear_bit(offset, cdev->watched_lines)) 2424 return -EBUSY; 2425 2426 return 0; 2427} 2428 2429/* 2430 * gpio_ioctl() - ioctl handler for the GPIO chardev 2431 */ 2432static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 2433{ 2434 struct gpio_chardev_data *cdev = file->private_data; 2435 struct gpio_device *gdev = cdev->gdev; 2436 void __user *ip = (void __user *)arg; 2437 2438 guard(srcu)(&gdev->srcu); 2439 2440 /* We fail any subsequent ioctl():s when the chip is gone */ 2441 if (!rcu_access_pointer(gdev->chip)) 2442 return -ENODEV; 2443 2444 /* Fill in the struct and pass to userspace */ 2445 switch (cmd) { 2446 case GPIO_GET_CHIPINFO_IOCTL: 2447 return chipinfo_get(cdev, ip); 2448#ifdef CONFIG_GPIO_CDEV_V1 2449 case GPIO_GET_LINEHANDLE_IOCTL: 2450 return linehandle_create(gdev, ip); 2451 case GPIO_GET_LINEEVENT_IOCTL: 2452 return lineevent_create(gdev, ip); 2453 case GPIO_GET_LINEINFO_IOCTL: 2454 return lineinfo_get_v1(cdev, ip, false); 2455 case GPIO_GET_LINEINFO_WATCH_IOCTL: 2456 return lineinfo_get_v1(cdev, ip, true); 2457#endif /* CONFIG_GPIO_CDEV_V1 */ 2458 case GPIO_V2_GET_LINEINFO_IOCTL: 2459 return lineinfo_get(cdev, ip, false); 2460 case GPIO_V2_GET_LINEINFO_WATCH_IOCTL: 2461 return lineinfo_get(cdev, ip, true); 2462 case GPIO_V2_GET_LINE_IOCTL: 2463 return linereq_create(gdev, ip); 2464 case GPIO_GET_LINEINFO_UNWATCH_IOCTL: 2465 return lineinfo_unwatch(cdev, ip); 2466 default: 2467 return -EINVAL; 2468 } 2469} 2470 2471#ifdef CONFIG_COMPAT 2472static long gpio_ioctl_compat(struct file *file, unsigned int cmd, 2473 unsigned long arg) 2474{ 2475 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 2476} 2477#endif 2478 2479struct lineinfo_changed_ctx { 2480 struct work_struct work; 2481 struct gpio_v2_line_info_changed chg; 2482 struct gpio_device *gdev; 2483 struct gpio_chardev_data *cdev; 2484}; 2485 2486static void lineinfo_changed_func(struct work_struct *work) 2487{ 2488 struct lineinfo_changed_ctx *ctx = 2489 container_of(work, struct lineinfo_changed_ctx, work); 2490 struct gpio_chip *gc; 2491 int ret; 2492 2493 if (!(ctx->chg.info.flags & GPIO_V2_LINE_FLAG_USED)) { 2494 /* 2495 * If nobody set the USED flag earlier, let's see with pinctrl 2496 * now. We're doing this late because it's a sleeping function. 2497 * Pin functions are in general much more static and while it's 2498 * not 100% bullet-proof, it's good enough for most cases. 2499 */ 2500 scoped_guard(srcu, &ctx->gdev->srcu) { 2501 gc = srcu_dereference(ctx->gdev->chip, &ctx->gdev->srcu); 2502 if (gc && 2503 !pinctrl_gpio_can_use_line(gc, ctx->chg.info.offset)) 2504 ctx->chg.info.flags |= GPIO_V2_LINE_FLAG_USED; 2505 } 2506 } 2507 2508 ret = kfifo_in_spinlocked(&ctx->cdev->events, &ctx->chg, 1, 2509 &ctx->cdev->wait.lock); 2510 if (ret) 2511 wake_up_poll(&ctx->cdev->wait, EPOLLIN); 2512 else 2513 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n"); 2514 2515 gpio_device_put(ctx->gdev); 2516 fput(ctx->cdev->fp); 2517 kfree(ctx); 2518} 2519 2520static int lineinfo_changed_notify(struct notifier_block *nb, 2521 unsigned long action, void *data) 2522{ 2523 struct gpio_chardev_data *cdev = 2524 container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb); 2525 struct lineinfo_changed_ctx *ctx; 2526 struct gpio_desc *desc = data; 2527 struct file *fp; 2528 2529 if (!test_bit(gpiod_hwgpio(desc), cdev->watched_lines)) 2530 return NOTIFY_DONE; 2531 2532 /* Keep the file descriptor alive for the duration of the notification. */ 2533 fp = get_file_active(&cdev->fp); 2534 if (!fp) 2535 /* Chardev file descriptor was or is being released. */ 2536 return NOTIFY_DONE; 2537 2538 /* 2539 * If this is called from atomic context (for instance: with a spinlock 2540 * taken by the atomic notifier chain), any sleeping calls must be done 2541 * outside of this function in process context of the dedicated 2542 * workqueue. 2543 * 2544 * Let's gather as much info as possible from the descriptor and 2545 * postpone just the call to pinctrl_gpio_can_use_line() until the work 2546 * is executed. 2547 */ 2548 2549 ctx = kzalloc(sizeof(*ctx), GFP_ATOMIC); 2550 if (!ctx) { 2551 pr_err("Failed to allocate memory for line info notification\n"); 2552 fput(fp); 2553 return NOTIFY_DONE; 2554 } 2555 2556 ctx->chg.event_type = action; 2557 ctx->chg.timestamp_ns = ktime_get_ns(); 2558 gpio_desc_to_lineinfo(desc, &ctx->chg.info, true); 2559 /* Keep the GPIO device alive until we emit the event. */ 2560 ctx->gdev = gpio_device_get(desc->gdev); 2561 ctx->cdev = cdev; 2562 2563 INIT_WORK(&ctx->work, lineinfo_changed_func); 2564 queue_work(ctx->gdev->line_state_wq, &ctx->work); 2565 2566 return NOTIFY_OK; 2567} 2568 2569static int gpio_device_unregistered_notify(struct notifier_block *nb, 2570 unsigned long action, void *data) 2571{ 2572 struct gpio_chardev_data *cdev = container_of(nb, 2573 struct gpio_chardev_data, 2574 device_unregistered_nb); 2575 2576 wake_up_poll(&cdev->wait, EPOLLIN | EPOLLERR); 2577 2578 return NOTIFY_OK; 2579} 2580 2581static __poll_t lineinfo_watch_poll(struct file *file, 2582 struct poll_table_struct *pollt) 2583{ 2584 struct gpio_chardev_data *cdev = file->private_data; 2585 __poll_t events = 0; 2586 2587 guard(srcu)(&cdev->gdev->srcu); 2588 2589 if (!rcu_access_pointer(cdev->gdev->chip)) 2590 return EPOLLHUP | EPOLLERR; 2591 2592 poll_wait(file, &cdev->wait, pollt); 2593 2594 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events, 2595 &cdev->wait.lock)) 2596 events = EPOLLIN | EPOLLRDNORM; 2597 2598 return events; 2599} 2600 2601static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, 2602 size_t count, loff_t *off) 2603{ 2604 struct gpio_chardev_data *cdev = file->private_data; 2605 struct gpio_v2_line_info_changed event; 2606 ssize_t bytes_read = 0; 2607 int ret; 2608 size_t event_size; 2609 2610 guard(srcu)(&cdev->gdev->srcu); 2611 2612 if (!rcu_access_pointer(cdev->gdev->chip)) 2613 return -ENODEV; 2614 2615#ifndef CONFIG_GPIO_CDEV_V1 2616 event_size = sizeof(struct gpio_v2_line_info_changed); 2617 if (count < event_size) 2618 return -EINVAL; 2619#endif 2620 2621 do { 2622 scoped_guard(spinlock, &cdev->wait.lock) { 2623 if (kfifo_is_empty(&cdev->events)) { 2624 if (bytes_read) 2625 return bytes_read; 2626 2627 if (file->f_flags & O_NONBLOCK) 2628 return -EAGAIN; 2629 2630 ret = wait_event_interruptible_locked(cdev->wait, 2631 !kfifo_is_empty(&cdev->events)); 2632 if (ret) 2633 return ret; 2634 } 2635#ifdef CONFIG_GPIO_CDEV_V1 2636 /* must be after kfifo check so watch_abi_version is set */ 2637 if (atomic_read(&cdev->watch_abi_version) == 2) 2638 event_size = sizeof(struct gpio_v2_line_info_changed); 2639 else 2640 event_size = sizeof(struct gpioline_info_changed); 2641 if (count < event_size) 2642 return -EINVAL; 2643#endif 2644 if (kfifo_out(&cdev->events, &event, 1) != 1) { 2645 /* 2646 * This should never happen - we hold the 2647 * lock from the moment we learned the fifo 2648 * is no longer empty until now. 2649 */ 2650 WARN(1, "failed to read from non-empty kfifo"); 2651 return -EIO; 2652 } 2653 } 2654 2655#ifdef CONFIG_GPIO_CDEV_V1 2656 if (event_size == sizeof(struct gpio_v2_line_info_changed)) { 2657 if (copy_to_user(buf + bytes_read, &event, event_size)) 2658 return -EFAULT; 2659 } else { 2660 struct gpioline_info_changed event_v1; 2661 2662 gpio_v2_line_info_changed_to_v1(&event, &event_v1); 2663 if (copy_to_user(buf + bytes_read, &event_v1, 2664 event_size)) 2665 return -EFAULT; 2666 } 2667#else 2668 if (copy_to_user(buf + bytes_read, &event, event_size)) 2669 return -EFAULT; 2670#endif 2671 bytes_read += event_size; 2672 } while (count >= bytes_read + sizeof(event)); 2673 2674 return bytes_read; 2675} 2676 2677/** 2678 * gpio_chrdev_open() - open the chardev for ioctl operations 2679 * @inode: inode for this chardev 2680 * @file: file struct for storing private data 2681 * 2682 * Returns: 2683 * 0 on success, or negative errno on failure. 2684 */ 2685static int gpio_chrdev_open(struct inode *inode, struct file *file) 2686{ 2687 struct gpio_device *gdev = container_of(inode->i_cdev, 2688 struct gpio_device, chrdev); 2689 struct gpio_chardev_data *cdev; 2690 int ret = -ENOMEM; 2691 2692 guard(srcu)(&gdev->srcu); 2693 2694 /* Fail on open if the backing gpiochip is gone */ 2695 if (!rcu_access_pointer(gdev->chip)) 2696 return -ENODEV; 2697 2698 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL); 2699 if (!cdev) 2700 return -ENOMEM; 2701 2702 cdev->watched_lines = bitmap_zalloc(gdev->ngpio, GFP_KERNEL); 2703 if (!cdev->watched_lines) 2704 goto out_free_cdev; 2705 2706 init_waitqueue_head(&cdev->wait); 2707 INIT_KFIFO(cdev->events); 2708 cdev->gdev = gpio_device_get(gdev); 2709 2710 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify; 2711 scoped_guard(write_lock_irqsave, &gdev->line_state_lock) 2712 ret = raw_notifier_chain_register(&gdev->line_state_notifier, 2713 &cdev->lineinfo_changed_nb); 2714 if (ret) 2715 goto out_free_bitmap; 2716 2717 cdev->device_unregistered_nb.notifier_call = 2718 gpio_device_unregistered_notify; 2719 ret = blocking_notifier_chain_register(&gdev->device_notifier, 2720 &cdev->device_unregistered_nb); 2721 if (ret) 2722 goto out_unregister_line_notifier; 2723 2724 file->private_data = cdev; 2725 cdev->fp = file; 2726 2727 ret = nonseekable_open(inode, file); 2728 if (ret) 2729 goto out_unregister_device_notifier; 2730 2731 return ret; 2732 2733out_unregister_device_notifier: 2734 blocking_notifier_chain_unregister(&gdev->device_notifier, 2735 &cdev->device_unregistered_nb); 2736out_unregister_line_notifier: 2737 scoped_guard(write_lock_irqsave, &gdev->line_state_lock) 2738 raw_notifier_chain_unregister(&gdev->line_state_notifier, 2739 &cdev->lineinfo_changed_nb); 2740out_free_bitmap: 2741 gpio_device_put(gdev); 2742 bitmap_free(cdev->watched_lines); 2743out_free_cdev: 2744 kfree(cdev); 2745 return ret; 2746} 2747 2748/** 2749 * gpio_chrdev_release() - close chardev after ioctl operations 2750 * @inode: inode for this chardev 2751 * @file: file struct for storing private data 2752 * 2753 * Returns: 2754 * 0 on success, or negative errno on failure. 2755 */ 2756static int gpio_chrdev_release(struct inode *inode, struct file *file) 2757{ 2758 struct gpio_chardev_data *cdev = file->private_data; 2759 struct gpio_device *gdev = cdev->gdev; 2760 2761 blocking_notifier_chain_unregister(&gdev->device_notifier, 2762 &cdev->device_unregistered_nb); 2763 scoped_guard(write_lock_irqsave, &gdev->line_state_lock) 2764 raw_notifier_chain_unregister(&gdev->line_state_notifier, 2765 &cdev->lineinfo_changed_nb); 2766 bitmap_free(cdev->watched_lines); 2767 gpio_device_put(gdev); 2768 kfree(cdev); 2769 2770 return 0; 2771} 2772 2773static const struct file_operations gpio_fileops = { 2774 .release = gpio_chrdev_release, 2775 .open = gpio_chrdev_open, 2776 .poll = lineinfo_watch_poll, 2777 .read = lineinfo_watch_read, 2778 .owner = THIS_MODULE, 2779 .unlocked_ioctl = gpio_ioctl, 2780#ifdef CONFIG_COMPAT 2781 .compat_ioctl = gpio_ioctl_compat, 2782#endif 2783}; 2784 2785int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt) 2786{ 2787 struct gpio_chip *gc; 2788 int ret; 2789 2790 cdev_init(&gdev->chrdev, &gpio_fileops); 2791 gdev->chrdev.owner = THIS_MODULE; 2792 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id); 2793 2794 gdev->line_state_wq = alloc_ordered_workqueue("%s", WQ_HIGHPRI, 2795 dev_name(&gdev->dev)); 2796 if (!gdev->line_state_wq) 2797 return -ENOMEM; 2798 2799 ret = cdev_device_add(&gdev->chrdev, &gdev->dev); 2800 if (ret) { 2801 destroy_workqueue(gdev->line_state_wq); 2802 return ret; 2803 } 2804 2805 guard(srcu)(&gdev->srcu); 2806 gc = srcu_dereference(gdev->chip, &gdev->srcu); 2807 if (!gc) { 2808 cdev_device_del(&gdev->chrdev, &gdev->dev); 2809 destroy_workqueue(gdev->line_state_wq); 2810 return -ENODEV; 2811 } 2812 2813 gpiochip_dbg(gc, "added GPIO chardev (%d:%d)\n", MAJOR(devt), gdev->id); 2814 2815 return 0; 2816} 2817 2818void gpiolib_cdev_unregister(struct gpio_device *gdev) 2819{ 2820 destroy_workqueue(gdev->line_state_wq); 2821 cdev_device_del(&gdev->chrdev, &gdev->dev); 2822 blocking_notifier_call_chain(&gdev->device_notifier, 0, NULL); 2823}
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