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/kernel.h> 20 #include <linux/kfifo.h> 21 #include <linux/module.h> 22 #include <linux/mutex.h> 23 #include <linux/pinctrl/consumer.h> 24 #include <linux/poll.h> 25 #include <linux/rbtree.h> 26 #include <linux/seq_file.h> 27 #include <linux/spinlock.h> 28 #include <linux/timekeeping.h> 29 #include <linux/uaccess.h> 30 #include <linux/workqueue.h> 31 32 #include <uapi/linux/gpio.h> 33 34 #include "gpiolib.h" 35 #include "gpiolib-cdev.h" 36 37 /* 38 * Array sizes must ensure 64-bit alignment and not create holes in the 39 * struct packing. 40 */ 41 static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2)); 42 static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8)); 43 44 /* 45 * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility 46 */ 47 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8)); 48 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8)); 49 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8)); 50 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8)); 51 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8)); 52 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8)); 53 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8)); 54 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8)); 55 56 /* Character device interface to GPIO. 57 * 58 * The GPIO character device, /dev/gpiochipN, provides userspace an 59 * interface to gpiolib GPIOs via ioctl()s. 60 */ 61 62 typedef __poll_t (*poll_fn)(struct file *, struct poll_table_struct *); 63 typedef long (*ioctl_fn)(struct file *, unsigned int, unsigned long); 64 typedef ssize_t (*read_fn)(struct file *, char __user *, 65 size_t count, loff_t *); 66 67 static __poll_t call_poll_locked(struct file *file, 68 struct poll_table_struct *wait, 69 struct gpio_device *gdev, poll_fn func) 70 { 71 __poll_t ret; 72 73 down_read(&gdev->sem); 74 ret = func(file, wait); 75 up_read(&gdev->sem); 76 77 return ret; 78 } 79 80 static long call_ioctl_locked(struct file *file, unsigned int cmd, 81 unsigned long arg, struct gpio_device *gdev, 82 ioctl_fn func) 83 { 84 long ret; 85 86 down_read(&gdev->sem); 87 ret = func(file, cmd, arg); 88 up_read(&gdev->sem); 89 90 return ret; 91 } 92 93 static ssize_t call_read_locked(struct file *file, char __user *buf, 94 size_t count, loff_t *f_ps, 95 struct gpio_device *gdev, read_fn func) 96 { 97 ssize_t ret; 98 99 down_read(&gdev->sem); 100 ret = func(file, buf, count, f_ps); 101 up_read(&gdev->sem); 102 103 return ret; 104 } 105 106 /* 107 * GPIO line handle management 108 */ 109 110 #ifdef CONFIG_GPIO_CDEV_V1 111 /** 112 * struct linehandle_state - contains the state of a userspace handle 113 * @gdev: the GPIO device the handle pertains to 114 * @label: consumer label used to tag descriptors 115 * @descs: the GPIO descriptors held by this handle 116 * @num_descs: the number of descriptors held in the descs array 117 */ 118 struct linehandle_state { 119 struct gpio_device *gdev; 120 const char *label; 121 struct gpio_desc *descs[GPIOHANDLES_MAX]; 122 u32 num_descs; 123 }; 124 125 #define GPIOHANDLE_REQUEST_VALID_FLAGS \ 126 (GPIOHANDLE_REQUEST_INPUT | \ 127 GPIOHANDLE_REQUEST_OUTPUT | \ 128 GPIOHANDLE_REQUEST_ACTIVE_LOW | \ 129 GPIOHANDLE_REQUEST_BIAS_PULL_UP | \ 130 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \ 131 GPIOHANDLE_REQUEST_BIAS_DISABLE | \ 132 GPIOHANDLE_REQUEST_OPEN_DRAIN | \ 133 GPIOHANDLE_REQUEST_OPEN_SOURCE) 134 135 static int linehandle_validate_flags(u32 flags) 136 { 137 /* Return an error if an unknown flag is set */ 138 if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) 139 return -EINVAL; 140 141 /* 142 * Do not allow both INPUT & OUTPUT flags to be set as they are 143 * contradictory. 144 */ 145 if ((flags & GPIOHANDLE_REQUEST_INPUT) && 146 (flags & GPIOHANDLE_REQUEST_OUTPUT)) 147 return -EINVAL; 148 149 /* 150 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If 151 * the hardware actually supports enabling both at the same time the 152 * electrical result would be disastrous. 153 */ 154 if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) && 155 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 156 return -EINVAL; 157 158 /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */ 159 if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) && 160 ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 161 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))) 162 return -EINVAL; 163 164 /* Bias flags only allowed for input or output mode. */ 165 if (!((flags & GPIOHANDLE_REQUEST_INPUT) || 166 (flags & GPIOHANDLE_REQUEST_OUTPUT)) && 167 ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) || 168 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) || 169 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN))) 170 return -EINVAL; 171 172 /* Only one bias flag can be set. */ 173 if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 174 (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 175 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 176 ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 177 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 178 return -EINVAL; 179 180 return 0; 181 } 182 183 static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp) 184 { 185 assign_bit(FLAG_ACTIVE_LOW, flagsp, 186 lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW); 187 assign_bit(FLAG_OPEN_DRAIN, flagsp, 188 lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN); 189 assign_bit(FLAG_OPEN_SOURCE, flagsp, 190 lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE); 191 assign_bit(FLAG_PULL_UP, flagsp, 192 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP); 193 assign_bit(FLAG_PULL_DOWN, flagsp, 194 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN); 195 assign_bit(FLAG_BIAS_DISABLE, flagsp, 196 lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE); 197 } 198 199 static long linehandle_set_config(struct linehandle_state *lh, 200 void __user *ip) 201 { 202 struct gpiohandle_config gcnf; 203 struct gpio_desc *desc; 204 int i, ret; 205 u32 lflags; 206 207 if (copy_from_user(&gcnf, ip, sizeof(gcnf))) 208 return -EFAULT; 209 210 lflags = gcnf.flags; 211 ret = linehandle_validate_flags(lflags); 212 if (ret) 213 return ret; 214 215 for (i = 0; i < lh->num_descs; i++) { 216 desc = lh->descs[i]; 217 linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags); 218 219 /* 220 * Lines have to be requested explicitly for input 221 * or output, else the line will be treated "as is". 222 */ 223 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { 224 int val = !!gcnf.default_values[i]; 225 226 ret = gpiod_direction_output(desc, val); 227 if (ret) 228 return ret; 229 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { 230 ret = gpiod_direction_input(desc); 231 if (ret) 232 return ret; 233 } 234 235 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG); 236 } 237 return 0; 238 } 239 240 static long linehandle_ioctl_unlocked(struct file *file, unsigned int cmd, 241 unsigned long arg) 242 { 243 struct linehandle_state *lh = file->private_data; 244 void __user *ip = (void __user *)arg; 245 struct gpiohandle_data ghd; 246 DECLARE_BITMAP(vals, GPIOHANDLES_MAX); 247 unsigned int i; 248 int ret; 249 250 if (!lh->gdev->chip) 251 return -ENODEV; 252 253 switch (cmd) { 254 case GPIOHANDLE_GET_LINE_VALUES_IOCTL: 255 /* NOTE: It's okay to read values of output lines */ 256 ret = gpiod_get_array_value_complex(false, true, 257 lh->num_descs, lh->descs, 258 NULL, vals); 259 if (ret) 260 return ret; 261 262 memset(&ghd, 0, sizeof(ghd)); 263 for (i = 0; i < lh->num_descs; i++) 264 ghd.values[i] = test_bit(i, vals); 265 266 if (copy_to_user(ip, &ghd, sizeof(ghd))) 267 return -EFAULT; 268 269 return 0; 270 case GPIOHANDLE_SET_LINE_VALUES_IOCTL: 271 /* 272 * All line descriptors were created at once with the same 273 * flags so just check if the first one is really output. 274 */ 275 if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags)) 276 return -EPERM; 277 278 if (copy_from_user(&ghd, ip, sizeof(ghd))) 279 return -EFAULT; 280 281 /* Clamp all values to [0,1] */ 282 for (i = 0; i < lh->num_descs; i++) 283 __assign_bit(i, vals, ghd.values[i]); 284 285 /* Reuse the array setting function */ 286 return gpiod_set_array_value_complex(false, 287 true, 288 lh->num_descs, 289 lh->descs, 290 NULL, 291 vals); 292 case GPIOHANDLE_SET_CONFIG_IOCTL: 293 return linehandle_set_config(lh, ip); 294 default: 295 return -EINVAL; 296 } 297 } 298 299 static long linehandle_ioctl(struct file *file, unsigned int cmd, 300 unsigned long arg) 301 { 302 struct linehandle_state *lh = file->private_data; 303 304 return call_ioctl_locked(file, cmd, arg, lh->gdev, 305 linehandle_ioctl_unlocked); 306 } 307 308 #ifdef CONFIG_COMPAT 309 static long linehandle_ioctl_compat(struct file *file, unsigned int cmd, 310 unsigned long arg) 311 { 312 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 313 } 314 #endif 315 316 static void linehandle_free(struct linehandle_state *lh) 317 { 318 int i; 319 320 for (i = 0; i < lh->num_descs; i++) 321 if (lh->descs[i]) 322 gpiod_free(lh->descs[i]); 323 kfree(lh->label); 324 gpio_device_put(lh->gdev); 325 kfree(lh); 326 } 327 328 static int linehandle_release(struct inode *inode, struct file *file) 329 { 330 linehandle_free(file->private_data); 331 return 0; 332 } 333 334 static const struct file_operations linehandle_fileops = { 335 .release = linehandle_release, 336 .owner = THIS_MODULE, 337 .llseek = noop_llseek, 338 .unlocked_ioctl = linehandle_ioctl, 339 #ifdef CONFIG_COMPAT 340 .compat_ioctl = linehandle_ioctl_compat, 341 #endif 342 }; 343 344 static int linehandle_create(struct gpio_device *gdev, void __user *ip) 345 { 346 struct gpiohandle_request handlereq; 347 struct linehandle_state *lh; 348 struct file *file; 349 int fd, i, ret; 350 u32 lflags; 351 352 if (copy_from_user(&handlereq, ip, sizeof(handlereq))) 353 return -EFAULT; 354 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX)) 355 return -EINVAL; 356 357 lflags = handlereq.flags; 358 359 ret = linehandle_validate_flags(lflags); 360 if (ret) 361 return ret; 362 363 lh = kzalloc(sizeof(*lh), GFP_KERNEL); 364 if (!lh) 365 return -ENOMEM; 366 lh->gdev = gpio_device_get(gdev); 367 368 if (handlereq.consumer_label[0] != '\0') { 369 /* label is only initialized if consumer_label is set */ 370 lh->label = kstrndup(handlereq.consumer_label, 371 sizeof(handlereq.consumer_label) - 1, 372 GFP_KERNEL); 373 if (!lh->label) { 374 ret = -ENOMEM; 375 goto out_free_lh; 376 } 377 } 378 379 lh->num_descs = handlereq.lines; 380 381 /* Request each GPIO */ 382 for (i = 0; i < handlereq.lines; i++) { 383 u32 offset = handlereq.lineoffsets[i]; 384 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset); 385 386 if (IS_ERR(desc)) { 387 ret = PTR_ERR(desc); 388 goto out_free_lh; 389 } 390 391 ret = gpiod_request_user(desc, lh->label); 392 if (ret) 393 goto out_free_lh; 394 lh->descs[i] = desc; 395 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags); 396 397 ret = gpiod_set_transitory(desc, false); 398 if (ret < 0) 399 goto out_free_lh; 400 401 /* 402 * Lines have to be requested explicitly for input 403 * or output, else the line will be treated "as is". 404 */ 405 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { 406 int val = !!handlereq.default_values[i]; 407 408 ret = gpiod_direction_output(desc, val); 409 if (ret) 410 goto out_free_lh; 411 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { 412 ret = gpiod_direction_input(desc); 413 if (ret) 414 goto out_free_lh; 415 } 416 417 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED); 418 419 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 420 offset); 421 } 422 423 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 424 if (fd < 0) { 425 ret = fd; 426 goto out_free_lh; 427 } 428 429 file = anon_inode_getfile("gpio-linehandle", 430 &linehandle_fileops, 431 lh, 432 O_RDONLY | O_CLOEXEC); 433 if (IS_ERR(file)) { 434 ret = PTR_ERR(file); 435 goto out_put_unused_fd; 436 } 437 438 handlereq.fd = fd; 439 if (copy_to_user(ip, &handlereq, sizeof(handlereq))) { 440 /* 441 * fput() will trigger the release() callback, so do not go onto 442 * the regular error cleanup path here. 443 */ 444 fput(file); 445 put_unused_fd(fd); 446 return -EFAULT; 447 } 448 449 fd_install(fd, file); 450 451 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 452 lh->num_descs); 453 454 return 0; 455 456 out_put_unused_fd: 457 put_unused_fd(fd); 458 out_free_lh: 459 linehandle_free(lh); 460 return ret; 461 } 462 #endif /* CONFIG_GPIO_CDEV_V1 */ 463 464 /** 465 * struct line - contains the state of a requested line 466 * @node: to store the object in supinfo_tree if supplemental 467 * @desc: the GPIO descriptor for this line. 468 * @req: the corresponding line request 469 * @irq: the interrupt triggered in response to events on this GPIO 470 * @edflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or 471 * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied 472 * @timestamp_ns: cache for the timestamp storing it between hardirq and 473 * IRQ thread, used to bring the timestamp close to the actual event 474 * @req_seqno: the seqno for the current edge event in the sequence of 475 * events for the corresponding line request. This is drawn from the @req. 476 * @line_seqno: the seqno for the current edge event in the sequence of 477 * events for this line. 478 * @work: the worker that implements software debouncing 479 * @debounce_period_us: the debounce period in microseconds 480 * @sw_debounced: flag indicating if the software debouncer is active 481 * @level: the current debounced physical level of the line 482 * @hdesc: the Hardware Timestamp Engine (HTE) descriptor 483 * @raw_level: the line level at the time of event 484 * @total_discard_seq: the running counter of the discarded events 485 * @last_seqno: the last sequence number before debounce period expires 486 */ 487 struct line { 488 struct rb_node node; 489 struct gpio_desc *desc; 490 /* 491 * -- edge detector specific fields -- 492 */ 493 struct linereq *req; 494 unsigned int irq; 495 /* 496 * The flags for the active edge detector configuration. 497 * 498 * edflags is set by linereq_create(), linereq_free(), and 499 * linereq_set_config_unlocked(), which are themselves mutually 500 * exclusive, and is accessed by edge_irq_thread(), 501 * process_hw_ts_thread() and debounce_work_func(), 502 * which can all live with a slightly stale value. 503 */ 504 u64 edflags; 505 /* 506 * timestamp_ns and req_seqno are accessed only by 507 * edge_irq_handler() and edge_irq_thread(), which are themselves 508 * mutually exclusive, so no additional protection is necessary. 509 */ 510 u64 timestamp_ns; 511 u32 req_seqno; 512 /* 513 * line_seqno is accessed by either edge_irq_thread() or 514 * debounce_work_func(), which are themselves mutually exclusive, 515 * so no additional protection is necessary. 516 */ 517 u32 line_seqno; 518 /* 519 * -- debouncer specific fields -- 520 */ 521 struct delayed_work work; 522 /* 523 * debounce_period_us is accessed by debounce_irq_handler() and 524 * process_hw_ts() which are disabled when modified by 525 * debounce_setup(), edge_detector_setup() or edge_detector_stop() 526 * or can live with a stale version when updated by 527 * edge_detector_update(). 528 * The modifying functions are themselves mutually exclusive. 529 */ 530 unsigned int debounce_period_us; 531 /* 532 * sw_debounce is accessed by linereq_set_config(), which is the 533 * only setter, and linereq_get_values(), which can live with a 534 * slightly stale value. 535 */ 536 unsigned int sw_debounced; 537 /* 538 * level is accessed by debounce_work_func(), which is the only 539 * setter, and linereq_get_values() which can live with a slightly 540 * stale value. 541 */ 542 unsigned int level; 543 #ifdef CONFIG_HTE 544 struct hte_ts_desc hdesc; 545 /* 546 * HTE provider sets line level at the time of event. The valid 547 * value is 0 or 1 and negative value for an error. 548 */ 549 int raw_level; 550 /* 551 * when sw_debounce is set on HTE enabled line, this is running 552 * counter of the discarded events. 553 */ 554 u32 total_discard_seq; 555 /* 556 * when sw_debounce is set on HTE enabled line, this variable records 557 * last sequence number before debounce period expires. 558 */ 559 u32 last_seqno; 560 #endif /* CONFIG_HTE */ 561 }; 562 563 /* 564 * a rbtree of the struct lines containing supplemental info. 565 * Used to populate gpio_v2_line_info with cdev specific fields not contained 566 * in the struct gpio_desc. 567 * A line is determined to contain supplemental information by 568 * line_has_supinfo(). 569 */ 570 static struct rb_root supinfo_tree = RB_ROOT; 571 /* covers supinfo_tree */ 572 static DEFINE_SPINLOCK(supinfo_lock); 573 574 /** 575 * struct linereq - contains the state of a userspace line request 576 * @gdev: the GPIO device the line request pertains to 577 * @label: consumer label used to tag GPIO descriptors 578 * @num_lines: the number of lines in the lines array 579 * @wait: wait queue that handles blocking reads of events 580 * @device_unregistered_nb: notifier block for receiving gdev unregister events 581 * @event_buffer_size: the number of elements allocated in @events 582 * @events: KFIFO for the GPIO events 583 * @seqno: the sequence number for edge events generated on all lines in 584 * this line request. Note that this is not used when @num_lines is 1, as 585 * the line_seqno is then the same and is cheaper to calculate. 586 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency 587 * of configuration, particularly multi-step accesses to desc flags and 588 * changes to supinfo status. 589 * @lines: the lines held by this line request, with @num_lines elements. 590 */ 591 struct linereq { 592 struct gpio_device *gdev; 593 const char *label; 594 u32 num_lines; 595 wait_queue_head_t wait; 596 struct notifier_block device_unregistered_nb; 597 u32 event_buffer_size; 598 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event); 599 atomic_t seqno; 600 struct mutex config_mutex; 601 struct line lines[]; 602 }; 603 604 static void supinfo_insert(struct line *line) 605 { 606 struct rb_node **new = &(supinfo_tree.rb_node), *parent = NULL; 607 struct line *entry; 608 609 guard(spinlock)(&supinfo_lock); 610 611 while (*new) { 612 entry = container_of(*new, struct line, node); 613 614 parent = *new; 615 if (line->desc < entry->desc) { 616 new = &((*new)->rb_left); 617 } else if (line->desc > entry->desc) { 618 new = &((*new)->rb_right); 619 } else { 620 /* this should never happen */ 621 WARN(1, "duplicate line inserted"); 622 return; 623 } 624 } 625 626 rb_link_node(&line->node, parent, new); 627 rb_insert_color(&line->node, &supinfo_tree); 628 } 629 630 static void supinfo_erase(struct line *line) 631 { 632 guard(spinlock)(&supinfo_lock); 633 634 rb_erase(&line->node, &supinfo_tree); 635 } 636 637 static struct line *supinfo_find(struct gpio_desc *desc) 638 { 639 struct rb_node *node = supinfo_tree.rb_node; 640 struct line *line; 641 642 while (node) { 643 line = container_of(node, struct line, node); 644 if (desc < line->desc) 645 node = node->rb_left; 646 else if (desc > line->desc) 647 node = node->rb_right; 648 else 649 return line; 650 } 651 return NULL; 652 } 653 654 static void supinfo_to_lineinfo(struct gpio_desc *desc, 655 struct gpio_v2_line_info *info) 656 { 657 struct gpio_v2_line_attribute *attr; 658 struct line *line; 659 660 guard(spinlock)(&supinfo_lock); 661 662 line = supinfo_find(desc); 663 if (!line) 664 return; 665 666 attr = &info->attrs[info->num_attrs]; 667 attr->id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; 668 attr->debounce_period_us = READ_ONCE(line->debounce_period_us); 669 info->num_attrs++; 670 } 671 672 static inline bool line_has_supinfo(struct line *line) 673 { 674 return READ_ONCE(line->debounce_period_us); 675 } 676 677 /* 678 * Checks line_has_supinfo() before and after the change to avoid unnecessary 679 * supinfo_tree access. 680 * Called indirectly by linereq_create() or linereq_set_config() so line 681 * is already protected from concurrent changes. 682 */ 683 static void line_set_debounce_period(struct line *line, 684 unsigned int debounce_period_us) 685 { 686 bool was_suppl = line_has_supinfo(line); 687 688 WRITE_ONCE(line->debounce_period_us, debounce_period_us); 689 690 /* if supinfo status is unchanged then we're done */ 691 if (line_has_supinfo(line) == was_suppl) 692 return; 693 694 /* supinfo status has changed, so update the tree */ 695 if (was_suppl) 696 supinfo_erase(line); 697 else 698 supinfo_insert(line); 699 } 700 701 #define GPIO_V2_LINE_BIAS_FLAGS \ 702 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \ 703 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \ 704 GPIO_V2_LINE_FLAG_BIAS_DISABLED) 705 706 #define GPIO_V2_LINE_DIRECTION_FLAGS \ 707 (GPIO_V2_LINE_FLAG_INPUT | \ 708 GPIO_V2_LINE_FLAG_OUTPUT) 709 710 #define GPIO_V2_LINE_DRIVE_FLAGS \ 711 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \ 712 GPIO_V2_LINE_FLAG_OPEN_SOURCE) 713 714 #define GPIO_V2_LINE_EDGE_FLAGS \ 715 (GPIO_V2_LINE_FLAG_EDGE_RISING | \ 716 GPIO_V2_LINE_FLAG_EDGE_FALLING) 717 718 #define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS 719 720 #define GPIO_V2_LINE_VALID_FLAGS \ 721 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ 722 GPIO_V2_LINE_DIRECTION_FLAGS | \ 723 GPIO_V2_LINE_DRIVE_FLAGS | \ 724 GPIO_V2_LINE_EDGE_FLAGS | \ 725 GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \ 726 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \ 727 GPIO_V2_LINE_BIAS_FLAGS) 728 729 /* subset of flags relevant for edge detector configuration */ 730 #define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \ 731 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ 732 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \ 733 GPIO_V2_LINE_EDGE_FLAGS) 734 735 static int linereq_unregistered_notify(struct notifier_block *nb, 736 unsigned long action, void *data) 737 { 738 struct linereq *lr = container_of(nb, struct linereq, 739 device_unregistered_nb); 740 741 wake_up_poll(&lr->wait, EPOLLIN | EPOLLERR); 742 743 return NOTIFY_OK; 744 } 745 746 static void linereq_put_event(struct linereq *lr, 747 struct gpio_v2_line_event *le) 748 { 749 bool overflow = false; 750 751 spin_lock(&lr->wait.lock); 752 if (kfifo_is_full(&lr->events)) { 753 overflow = true; 754 kfifo_skip(&lr->events); 755 } 756 kfifo_in(&lr->events, le, 1); 757 spin_unlock(&lr->wait.lock); 758 if (!overflow) 759 wake_up_poll(&lr->wait, EPOLLIN); 760 else 761 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 762 } 763 764 static u64 line_event_timestamp(struct line *line) 765 { 766 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags)) 767 return ktime_get_real_ns(); 768 else if (IS_ENABLED(CONFIG_HTE) && 769 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags)) 770 return line->timestamp_ns; 771 772 return ktime_get_ns(); 773 } 774 775 static u32 line_event_id(int level) 776 { 777 return level ? GPIO_V2_LINE_EVENT_RISING_EDGE : 778 GPIO_V2_LINE_EVENT_FALLING_EDGE; 779 } 780 781 static inline char *make_irq_label(const char *orig) 782 { 783 char *new; 784 785 if (!orig) 786 return NULL; 787 788 new = kstrdup_and_replace(orig, '/', ':', GFP_KERNEL); 789 if (!new) 790 return ERR_PTR(-ENOMEM); 791 792 return new; 793 } 794 795 static inline void free_irq_label(const char *label) 796 { 797 kfree(label); 798 } 799 800 #ifdef CONFIG_HTE 801 802 static enum hte_return process_hw_ts_thread(void *p) 803 { 804 struct line *line; 805 struct linereq *lr; 806 struct gpio_v2_line_event le; 807 u64 edflags; 808 int level; 809 810 if (!p) 811 return HTE_CB_HANDLED; 812 813 line = p; 814 lr = line->req; 815 816 memset(&le, 0, sizeof(le)); 817 818 le.timestamp_ns = line->timestamp_ns; 819 edflags = READ_ONCE(line->edflags); 820 821 switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) { 822 case GPIO_V2_LINE_FLAG_EDGE_BOTH: 823 level = (line->raw_level >= 0) ? 824 line->raw_level : 825 gpiod_get_raw_value_cansleep(line->desc); 826 827 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 828 level = !level; 829 830 le.id = line_event_id(level); 831 break; 832 case GPIO_V2_LINE_FLAG_EDGE_RISING: 833 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 834 break; 835 case GPIO_V2_LINE_FLAG_EDGE_FALLING: 836 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 837 break; 838 default: 839 return HTE_CB_HANDLED; 840 } 841 le.line_seqno = line->line_seqno; 842 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno; 843 le.offset = gpio_chip_hwgpio(line->desc); 844 845 linereq_put_event(lr, &le); 846 847 return HTE_CB_HANDLED; 848 } 849 850 static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p) 851 { 852 struct line *line; 853 struct linereq *lr; 854 int diff_seqno = 0; 855 856 if (!ts || !p) 857 return HTE_CB_HANDLED; 858 859 line = p; 860 line->timestamp_ns = ts->tsc; 861 line->raw_level = ts->raw_level; 862 lr = line->req; 863 864 if (READ_ONCE(line->sw_debounced)) { 865 line->total_discard_seq++; 866 line->last_seqno = ts->seq; 867 mod_delayed_work(system_wq, &line->work, 868 usecs_to_jiffies(READ_ONCE(line->debounce_period_us))); 869 } else { 870 if (unlikely(ts->seq < line->line_seqno)) 871 return HTE_CB_HANDLED; 872 873 diff_seqno = ts->seq - line->line_seqno; 874 line->line_seqno = ts->seq; 875 if (lr->num_lines != 1) 876 line->req_seqno = atomic_add_return(diff_seqno, 877 &lr->seqno); 878 879 return HTE_RUN_SECOND_CB; 880 } 881 882 return HTE_CB_HANDLED; 883 } 884 885 static int hte_edge_setup(struct line *line, u64 eflags) 886 { 887 int ret; 888 unsigned long flags = 0; 889 struct hte_ts_desc *hdesc = &line->hdesc; 890 891 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING) 892 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 893 HTE_FALLING_EDGE_TS : 894 HTE_RISING_EDGE_TS; 895 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING) 896 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 897 HTE_RISING_EDGE_TS : 898 HTE_FALLING_EDGE_TS; 899 900 line->total_discard_seq = 0; 901 902 hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL, 903 line->desc); 904 905 ret = hte_ts_get(NULL, hdesc, 0); 906 if (ret) 907 return ret; 908 909 return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread, 910 line); 911 } 912 913 #else 914 915 static int hte_edge_setup(struct line *line, u64 eflags) 916 { 917 return 0; 918 } 919 #endif /* CONFIG_HTE */ 920 921 static irqreturn_t edge_irq_thread(int irq, void *p) 922 { 923 struct line *line = p; 924 struct linereq *lr = line->req; 925 struct gpio_v2_line_event le; 926 927 /* Do not leak kernel stack to userspace */ 928 memset(&le, 0, sizeof(le)); 929 930 if (line->timestamp_ns) { 931 le.timestamp_ns = line->timestamp_ns; 932 } else { 933 /* 934 * We may be running from a nested threaded interrupt in 935 * which case we didn't get the timestamp from 936 * edge_irq_handler(). 937 */ 938 le.timestamp_ns = line_event_timestamp(line); 939 if (lr->num_lines != 1) 940 line->req_seqno = atomic_inc_return(&lr->seqno); 941 } 942 line->timestamp_ns = 0; 943 944 switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) { 945 case GPIO_V2_LINE_FLAG_EDGE_BOTH: 946 le.id = line_event_id(gpiod_get_value_cansleep(line->desc)); 947 break; 948 case GPIO_V2_LINE_FLAG_EDGE_RISING: 949 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE; 950 break; 951 case GPIO_V2_LINE_FLAG_EDGE_FALLING: 952 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE; 953 break; 954 default: 955 return IRQ_NONE; 956 } 957 line->line_seqno++; 958 le.line_seqno = line->line_seqno; 959 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno; 960 le.offset = gpio_chip_hwgpio(line->desc); 961 962 linereq_put_event(lr, &le); 963 964 return IRQ_HANDLED; 965 } 966 967 static irqreturn_t edge_irq_handler(int irq, void *p) 968 { 969 struct line *line = p; 970 struct linereq *lr = line->req; 971 972 /* 973 * Just store the timestamp in hardirq context so we get it as 974 * close in time as possible to the actual event. 975 */ 976 line->timestamp_ns = line_event_timestamp(line); 977 978 if (lr->num_lines != 1) 979 line->req_seqno = atomic_inc_return(&lr->seqno); 980 981 return IRQ_WAKE_THREAD; 982 } 983 984 /* 985 * returns the current debounced logical value. 986 */ 987 static bool debounced_value(struct line *line) 988 { 989 bool value; 990 991 /* 992 * minor race - debouncer may be stopped here, so edge_detector_stop() 993 * must leave the value unchanged so the following will read the level 994 * from when the debouncer was last running. 995 */ 996 value = READ_ONCE(line->level); 997 998 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags)) 999 value = !value; 1000 1001 return value; 1002 } 1003 1004 static irqreturn_t debounce_irq_handler(int irq, void *p) 1005 { 1006 struct line *line = p; 1007 1008 mod_delayed_work(system_wq, &line->work, 1009 usecs_to_jiffies(READ_ONCE(line->debounce_period_us))); 1010 1011 return IRQ_HANDLED; 1012 } 1013 1014 static void debounce_work_func(struct work_struct *work) 1015 { 1016 struct gpio_v2_line_event le; 1017 struct line *line = container_of(work, struct line, work.work); 1018 struct linereq *lr; 1019 u64 eflags, edflags = READ_ONCE(line->edflags); 1020 int level = -1; 1021 #ifdef CONFIG_HTE 1022 int diff_seqno; 1023 1024 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) 1025 level = line->raw_level; 1026 #endif 1027 if (level < 0) 1028 level = gpiod_get_raw_value_cansleep(line->desc); 1029 if (level < 0) { 1030 pr_debug_ratelimited("debouncer failed to read line value\n"); 1031 return; 1032 } 1033 1034 if (READ_ONCE(line->level) == level) 1035 return; 1036 1037 WRITE_ONCE(line->level, level); 1038 1039 /* -- edge detection -- */ 1040 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS; 1041 if (!eflags) 1042 return; 1043 1044 /* switch from physical level to logical - if they differ */ 1045 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 1046 level = !level; 1047 1048 /* ignore edges that are not being monitored */ 1049 if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) || 1050 ((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level)) 1051 return; 1052 1053 /* Do not leak kernel stack to userspace */ 1054 memset(&le, 0, sizeof(le)); 1055 1056 lr = line->req; 1057 le.timestamp_ns = line_event_timestamp(line); 1058 le.offset = gpio_chip_hwgpio(line->desc); 1059 #ifdef CONFIG_HTE 1060 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) { 1061 /* discard events except the last one */ 1062 line->total_discard_seq -= 1; 1063 diff_seqno = line->last_seqno - line->total_discard_seq - 1064 line->line_seqno; 1065 line->line_seqno = line->last_seqno - line->total_discard_seq; 1066 le.line_seqno = line->line_seqno; 1067 le.seqno = (lr->num_lines == 1) ? 1068 le.line_seqno : atomic_add_return(diff_seqno, &lr->seqno); 1069 } else 1070 #endif /* CONFIG_HTE */ 1071 { 1072 line->line_seqno++; 1073 le.line_seqno = line->line_seqno; 1074 le.seqno = (lr->num_lines == 1) ? 1075 le.line_seqno : atomic_inc_return(&lr->seqno); 1076 } 1077 1078 le.id = line_event_id(level); 1079 1080 linereq_put_event(lr, &le); 1081 } 1082 1083 static int debounce_setup(struct line *line, unsigned int debounce_period_us) 1084 { 1085 unsigned long irqflags; 1086 int ret, level, irq; 1087 char *label; 1088 1089 /* try hardware */ 1090 ret = gpiod_set_debounce(line->desc, debounce_period_us); 1091 if (!ret) { 1092 line_set_debounce_period(line, debounce_period_us); 1093 return ret; 1094 } 1095 if (ret != -ENOTSUPP) 1096 return ret; 1097 1098 if (debounce_period_us) { 1099 /* setup software debounce */ 1100 level = gpiod_get_raw_value_cansleep(line->desc); 1101 if (level < 0) 1102 return level; 1103 1104 if (!(IS_ENABLED(CONFIG_HTE) && 1105 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) { 1106 irq = gpiod_to_irq(line->desc); 1107 if (irq < 0) 1108 return -ENXIO; 1109 1110 label = make_irq_label(line->req->label); 1111 if (IS_ERR(label)) 1112 return -ENOMEM; 1113 1114 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING; 1115 ret = request_irq(irq, debounce_irq_handler, irqflags, 1116 label, line); 1117 if (ret) { 1118 free_irq_label(label); 1119 return ret; 1120 } 1121 line->irq = irq; 1122 } else { 1123 ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH); 1124 if (ret) 1125 return ret; 1126 } 1127 1128 WRITE_ONCE(line->level, level); 1129 WRITE_ONCE(line->sw_debounced, 1); 1130 } 1131 return 0; 1132 } 1133 1134 static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc, 1135 unsigned int line_idx) 1136 { 1137 unsigned int i; 1138 u64 mask = BIT_ULL(line_idx); 1139 1140 for (i = 0; i < lc->num_attrs; i++) { 1141 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 1142 (lc->attrs[i].mask & mask)) 1143 return true; 1144 } 1145 return false; 1146 } 1147 1148 static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc, 1149 unsigned int line_idx) 1150 { 1151 unsigned int i; 1152 u64 mask = BIT_ULL(line_idx); 1153 1154 for (i = 0; i < lc->num_attrs; i++) { 1155 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) && 1156 (lc->attrs[i].mask & mask)) 1157 return lc->attrs[i].attr.debounce_period_us; 1158 } 1159 return 0; 1160 } 1161 1162 static void edge_detector_stop(struct line *line) 1163 { 1164 if (line->irq) { 1165 free_irq_label(free_irq(line->irq, line)); 1166 line->irq = 0; 1167 } 1168 1169 #ifdef CONFIG_HTE 1170 if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) 1171 hte_ts_put(&line->hdesc); 1172 #endif 1173 1174 cancel_delayed_work_sync(&line->work); 1175 WRITE_ONCE(line->sw_debounced, 0); 1176 WRITE_ONCE(line->edflags, 0); 1177 line_set_debounce_period(line, 0); 1178 /* do not change line->level - see comment in debounced_value() */ 1179 } 1180 1181 static int edge_detector_setup(struct line *line, 1182 struct gpio_v2_line_config *lc, 1183 unsigned int line_idx, u64 edflags) 1184 { 1185 u32 debounce_period_us; 1186 unsigned long irqflags = 0; 1187 u64 eflags; 1188 int irq, ret; 1189 char *label; 1190 1191 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS; 1192 if (eflags && !kfifo_initialized(&line->req->events)) { 1193 ret = kfifo_alloc(&line->req->events, 1194 line->req->event_buffer_size, GFP_KERNEL); 1195 if (ret) 1196 return ret; 1197 } 1198 if (gpio_v2_line_config_debounced(lc, line_idx)) { 1199 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx); 1200 ret = debounce_setup(line, debounce_period_us); 1201 if (ret) 1202 return ret; 1203 line_set_debounce_period(line, debounce_period_us); 1204 } 1205 1206 /* detection disabled or sw debouncer will provide edge detection */ 1207 if (!eflags || READ_ONCE(line->sw_debounced)) 1208 return 0; 1209 1210 if (IS_ENABLED(CONFIG_HTE) && 1211 (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1212 return hte_edge_setup(line, edflags); 1213 1214 irq = gpiod_to_irq(line->desc); 1215 if (irq < 0) 1216 return -ENXIO; 1217 1218 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING) 1219 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 1220 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 1221 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING) 1222 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ? 1223 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 1224 irqflags |= IRQF_ONESHOT; 1225 1226 label = make_irq_label(line->req->label); 1227 if (IS_ERR(label)) 1228 return PTR_ERR(label); 1229 1230 /* Request a thread to read the events */ 1231 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread, 1232 irqflags, label, line); 1233 if (ret) { 1234 free_irq_label(label); 1235 return ret; 1236 } 1237 1238 line->irq = irq; 1239 return 0; 1240 } 1241 1242 static int edge_detector_update(struct line *line, 1243 struct gpio_v2_line_config *lc, 1244 unsigned int line_idx, u64 edflags) 1245 { 1246 u64 eflags; 1247 int ret; 1248 u64 active_edflags = READ_ONCE(line->edflags); 1249 unsigned int debounce_period_us = 1250 gpio_v2_line_config_debounce_period(lc, line_idx); 1251 1252 if ((active_edflags == edflags) && 1253 (READ_ONCE(line->debounce_period_us) == debounce_period_us)) 1254 return 0; 1255 1256 /* sw debounced and still will be...*/ 1257 if (debounce_period_us && READ_ONCE(line->sw_debounced)) { 1258 line_set_debounce_period(line, debounce_period_us); 1259 /* 1260 * ensure event fifo is initialised if edge detection 1261 * is now enabled. 1262 */ 1263 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS; 1264 if (eflags && !kfifo_initialized(&line->req->events)) { 1265 ret = kfifo_alloc(&line->req->events, 1266 line->req->event_buffer_size, 1267 GFP_KERNEL); 1268 if (ret) 1269 return ret; 1270 } 1271 return 0; 1272 } 1273 1274 /* reconfiguring edge detection or sw debounce being disabled */ 1275 if ((line->irq && !READ_ONCE(line->sw_debounced)) || 1276 (active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) || 1277 (!debounce_period_us && READ_ONCE(line->sw_debounced))) 1278 edge_detector_stop(line); 1279 1280 return edge_detector_setup(line, lc, line_idx, edflags); 1281 } 1282 1283 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc, 1284 unsigned int line_idx) 1285 { 1286 unsigned int i; 1287 u64 mask = BIT_ULL(line_idx); 1288 1289 for (i = 0; i < lc->num_attrs; i++) { 1290 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) && 1291 (lc->attrs[i].mask & mask)) 1292 return lc->attrs[i].attr.flags; 1293 } 1294 return lc->flags; 1295 } 1296 1297 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc, 1298 unsigned int line_idx) 1299 { 1300 unsigned int i; 1301 u64 mask = BIT_ULL(line_idx); 1302 1303 for (i = 0; i < lc->num_attrs; i++) { 1304 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) && 1305 (lc->attrs[i].mask & mask)) 1306 return !!(lc->attrs[i].attr.values & mask); 1307 } 1308 return 0; 1309 } 1310 1311 static int gpio_v2_line_flags_validate(u64 flags) 1312 { 1313 /* Return an error if an unknown flag is set */ 1314 if (flags & ~GPIO_V2_LINE_VALID_FLAGS) 1315 return -EINVAL; 1316 1317 if (!IS_ENABLED(CONFIG_HTE) && 1318 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1319 return -EOPNOTSUPP; 1320 1321 /* 1322 * Do not allow both INPUT and OUTPUT flags to be set as they are 1323 * contradictory. 1324 */ 1325 if ((flags & GPIO_V2_LINE_FLAG_INPUT) && 1326 (flags & GPIO_V2_LINE_FLAG_OUTPUT)) 1327 return -EINVAL; 1328 1329 /* Only allow one event clock source */ 1330 if (IS_ENABLED(CONFIG_HTE) && 1331 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME) && 1332 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)) 1333 return -EINVAL; 1334 1335 /* Edge detection requires explicit input. */ 1336 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) && 1337 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 1338 return -EINVAL; 1339 1340 /* 1341 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single 1342 * request. If the hardware actually supports enabling both at the 1343 * same time the electrical result would be disastrous. 1344 */ 1345 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) && 1346 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE)) 1347 return -EINVAL; 1348 1349 /* Drive requires explicit output direction. */ 1350 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) && 1351 !(flags & GPIO_V2_LINE_FLAG_OUTPUT)) 1352 return -EINVAL; 1353 1354 /* Bias requires explicit direction. */ 1355 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) && 1356 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS)) 1357 return -EINVAL; 1358 1359 /* Only one bias flag can be set. */ 1360 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) && 1361 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | 1362 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) || 1363 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) && 1364 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) 1365 return -EINVAL; 1366 1367 return 0; 1368 } 1369 1370 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc, 1371 unsigned int num_lines) 1372 { 1373 unsigned int i; 1374 u64 flags; 1375 int ret; 1376 1377 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX) 1378 return -EINVAL; 1379 1380 if (memchr_inv(lc->padding, 0, sizeof(lc->padding))) 1381 return -EINVAL; 1382 1383 for (i = 0; i < num_lines; i++) { 1384 flags = gpio_v2_line_config_flags(lc, i); 1385 ret = gpio_v2_line_flags_validate(flags); 1386 if (ret) 1387 return ret; 1388 1389 /* debounce requires explicit input */ 1390 if (gpio_v2_line_config_debounced(lc, i) && 1391 !(flags & GPIO_V2_LINE_FLAG_INPUT)) 1392 return -EINVAL; 1393 } 1394 return 0; 1395 } 1396 1397 static void gpio_v2_line_config_flags_to_desc_flags(u64 flags, 1398 unsigned long *flagsp) 1399 { 1400 assign_bit(FLAG_ACTIVE_LOW, flagsp, 1401 flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW); 1402 1403 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) 1404 set_bit(FLAG_IS_OUT, flagsp); 1405 else if (flags & GPIO_V2_LINE_FLAG_INPUT) 1406 clear_bit(FLAG_IS_OUT, flagsp); 1407 1408 assign_bit(FLAG_EDGE_RISING, flagsp, 1409 flags & GPIO_V2_LINE_FLAG_EDGE_RISING); 1410 assign_bit(FLAG_EDGE_FALLING, flagsp, 1411 flags & GPIO_V2_LINE_FLAG_EDGE_FALLING); 1412 1413 assign_bit(FLAG_OPEN_DRAIN, flagsp, 1414 flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN); 1415 assign_bit(FLAG_OPEN_SOURCE, flagsp, 1416 flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE); 1417 1418 assign_bit(FLAG_PULL_UP, flagsp, 1419 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP); 1420 assign_bit(FLAG_PULL_DOWN, flagsp, 1421 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN); 1422 assign_bit(FLAG_BIAS_DISABLE, flagsp, 1423 flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED); 1424 1425 assign_bit(FLAG_EVENT_CLOCK_REALTIME, flagsp, 1426 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME); 1427 assign_bit(FLAG_EVENT_CLOCK_HTE, flagsp, 1428 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE); 1429 } 1430 1431 static long linereq_get_values(struct linereq *lr, void __user *ip) 1432 { 1433 struct gpio_v2_line_values lv; 1434 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1435 struct gpio_desc **descs; 1436 unsigned int i, didx, num_get; 1437 bool val; 1438 int ret; 1439 1440 /* NOTE: It's ok to read values of output lines. */ 1441 if (copy_from_user(&lv, ip, sizeof(lv))) 1442 return -EFAULT; 1443 1444 for (num_get = 0, i = 0; i < lr->num_lines; i++) { 1445 if (lv.mask & BIT_ULL(i)) { 1446 num_get++; 1447 descs = &lr->lines[i].desc; 1448 } 1449 } 1450 1451 if (num_get == 0) 1452 return -EINVAL; 1453 1454 if (num_get != 1) { 1455 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL); 1456 if (!descs) 1457 return -ENOMEM; 1458 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1459 if (lv.mask & BIT_ULL(i)) { 1460 descs[didx] = lr->lines[i].desc; 1461 didx++; 1462 } 1463 } 1464 } 1465 ret = gpiod_get_array_value_complex(false, true, num_get, 1466 descs, NULL, vals); 1467 1468 if (num_get != 1) 1469 kfree(descs); 1470 if (ret) 1471 return ret; 1472 1473 lv.bits = 0; 1474 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1475 if (lv.mask & BIT_ULL(i)) { 1476 if (lr->lines[i].sw_debounced) 1477 val = debounced_value(&lr->lines[i]); 1478 else 1479 val = test_bit(didx, vals); 1480 if (val) 1481 lv.bits |= BIT_ULL(i); 1482 didx++; 1483 } 1484 } 1485 1486 if (copy_to_user(ip, &lv, sizeof(lv))) 1487 return -EFAULT; 1488 1489 return 0; 1490 } 1491 1492 static long linereq_set_values_unlocked(struct linereq *lr, 1493 struct gpio_v2_line_values *lv) 1494 { 1495 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 1496 struct gpio_desc **descs; 1497 unsigned int i, didx, num_set; 1498 int ret; 1499 1500 bitmap_zero(vals, GPIO_V2_LINES_MAX); 1501 for (num_set = 0, i = 0; i < lr->num_lines; i++) { 1502 if (lv->mask & BIT_ULL(i)) { 1503 if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags)) 1504 return -EPERM; 1505 if (lv->bits & BIT_ULL(i)) 1506 __set_bit(num_set, vals); 1507 num_set++; 1508 descs = &lr->lines[i].desc; 1509 } 1510 } 1511 if (num_set == 0) 1512 return -EINVAL; 1513 1514 if (num_set != 1) { 1515 /* build compacted desc array and values */ 1516 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL); 1517 if (!descs) 1518 return -ENOMEM; 1519 for (didx = 0, i = 0; i < lr->num_lines; i++) { 1520 if (lv->mask & BIT_ULL(i)) { 1521 descs[didx] = lr->lines[i].desc; 1522 didx++; 1523 } 1524 } 1525 } 1526 ret = gpiod_set_array_value_complex(false, true, num_set, 1527 descs, NULL, vals); 1528 1529 if (num_set != 1) 1530 kfree(descs); 1531 return ret; 1532 } 1533 1534 static long linereq_set_values(struct linereq *lr, void __user *ip) 1535 { 1536 struct gpio_v2_line_values lv; 1537 int ret; 1538 1539 if (copy_from_user(&lv, ip, sizeof(lv))) 1540 return -EFAULT; 1541 1542 mutex_lock(&lr->config_mutex); 1543 1544 ret = linereq_set_values_unlocked(lr, &lv); 1545 1546 mutex_unlock(&lr->config_mutex); 1547 1548 return ret; 1549 } 1550 1551 static long linereq_set_config_unlocked(struct linereq *lr, 1552 struct gpio_v2_line_config *lc) 1553 { 1554 struct gpio_desc *desc; 1555 struct line *line; 1556 unsigned int i; 1557 u64 flags, edflags; 1558 int ret; 1559 1560 for (i = 0; i < lr->num_lines; i++) { 1561 line = &lr->lines[i]; 1562 desc = lr->lines[i].desc; 1563 flags = gpio_v2_line_config_flags(lc, i); 1564 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1565 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS; 1566 /* 1567 * Lines have to be requested explicitly for input 1568 * or output, else the line will be treated "as is". 1569 */ 1570 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1571 int val = gpio_v2_line_config_output_value(lc, i); 1572 1573 edge_detector_stop(line); 1574 ret = gpiod_direction_output(desc, val); 1575 if (ret) 1576 return ret; 1577 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1578 ret = gpiod_direction_input(desc); 1579 if (ret) 1580 return ret; 1581 1582 ret = edge_detector_update(line, lc, i, edflags); 1583 if (ret) 1584 return ret; 1585 } 1586 1587 WRITE_ONCE(line->edflags, edflags); 1588 1589 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG); 1590 } 1591 return 0; 1592 } 1593 1594 static long linereq_set_config(struct linereq *lr, void __user *ip) 1595 { 1596 struct gpio_v2_line_config lc; 1597 int ret; 1598 1599 if (copy_from_user(&lc, ip, sizeof(lc))) 1600 return -EFAULT; 1601 1602 ret = gpio_v2_line_config_validate(&lc, lr->num_lines); 1603 if (ret) 1604 return ret; 1605 1606 mutex_lock(&lr->config_mutex); 1607 1608 ret = linereq_set_config_unlocked(lr, &lc); 1609 1610 mutex_unlock(&lr->config_mutex); 1611 1612 return ret; 1613 } 1614 1615 static long linereq_ioctl_unlocked(struct file *file, unsigned int cmd, 1616 unsigned long arg) 1617 { 1618 struct linereq *lr = file->private_data; 1619 void __user *ip = (void __user *)arg; 1620 1621 if (!lr->gdev->chip) 1622 return -ENODEV; 1623 1624 switch (cmd) { 1625 case GPIO_V2_LINE_GET_VALUES_IOCTL: 1626 return linereq_get_values(lr, ip); 1627 case GPIO_V2_LINE_SET_VALUES_IOCTL: 1628 return linereq_set_values(lr, ip); 1629 case GPIO_V2_LINE_SET_CONFIG_IOCTL: 1630 return linereq_set_config(lr, ip); 1631 default: 1632 return -EINVAL; 1633 } 1634 } 1635 1636 static long linereq_ioctl(struct file *file, unsigned int cmd, 1637 unsigned long arg) 1638 { 1639 struct linereq *lr = file->private_data; 1640 1641 return call_ioctl_locked(file, cmd, arg, lr->gdev, 1642 linereq_ioctl_unlocked); 1643 } 1644 1645 #ifdef CONFIG_COMPAT 1646 static long linereq_ioctl_compat(struct file *file, unsigned int cmd, 1647 unsigned long arg) 1648 { 1649 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1650 } 1651 #endif 1652 1653 static __poll_t linereq_poll_unlocked(struct file *file, 1654 struct poll_table_struct *wait) 1655 { 1656 struct linereq *lr = file->private_data; 1657 __poll_t events = 0; 1658 1659 if (!lr->gdev->chip) 1660 return EPOLLHUP | EPOLLERR; 1661 1662 poll_wait(file, &lr->wait, wait); 1663 1664 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events, 1665 &lr->wait.lock)) 1666 events = EPOLLIN | EPOLLRDNORM; 1667 1668 return events; 1669 } 1670 1671 static __poll_t linereq_poll(struct file *file, 1672 struct poll_table_struct *wait) 1673 { 1674 struct linereq *lr = file->private_data; 1675 1676 return call_poll_locked(file, wait, lr->gdev, linereq_poll_unlocked); 1677 } 1678 1679 static ssize_t linereq_read_unlocked(struct file *file, char __user *buf, 1680 size_t count, loff_t *f_ps) 1681 { 1682 struct linereq *lr = file->private_data; 1683 struct gpio_v2_line_event le; 1684 ssize_t bytes_read = 0; 1685 int ret; 1686 1687 if (!lr->gdev->chip) 1688 return -ENODEV; 1689 1690 if (count < sizeof(le)) 1691 return -EINVAL; 1692 1693 do { 1694 spin_lock(&lr->wait.lock); 1695 if (kfifo_is_empty(&lr->events)) { 1696 if (bytes_read) { 1697 spin_unlock(&lr->wait.lock); 1698 return bytes_read; 1699 } 1700 1701 if (file->f_flags & O_NONBLOCK) { 1702 spin_unlock(&lr->wait.lock); 1703 return -EAGAIN; 1704 } 1705 1706 ret = wait_event_interruptible_locked(lr->wait, 1707 !kfifo_is_empty(&lr->events)); 1708 if (ret) { 1709 spin_unlock(&lr->wait.lock); 1710 return ret; 1711 } 1712 } 1713 1714 ret = kfifo_out(&lr->events, &le, 1); 1715 spin_unlock(&lr->wait.lock); 1716 if (ret != 1) { 1717 /* 1718 * This should never happen - we were holding the 1719 * lock from the moment we learned the fifo is no 1720 * longer empty until now. 1721 */ 1722 ret = -EIO; 1723 break; 1724 } 1725 1726 if (copy_to_user(buf + bytes_read, &le, sizeof(le))) 1727 return -EFAULT; 1728 bytes_read += sizeof(le); 1729 } while (count >= bytes_read + sizeof(le)); 1730 1731 return bytes_read; 1732 } 1733 1734 static ssize_t linereq_read(struct file *file, char __user *buf, 1735 size_t count, loff_t *f_ps) 1736 { 1737 struct linereq *lr = file->private_data; 1738 1739 return call_read_locked(file, buf, count, f_ps, lr->gdev, 1740 linereq_read_unlocked); 1741 } 1742 1743 static void linereq_free(struct linereq *lr) 1744 { 1745 struct line *line; 1746 unsigned int i; 1747 1748 if (lr->device_unregistered_nb.notifier_call) 1749 blocking_notifier_chain_unregister(&lr->gdev->device_notifier, 1750 &lr->device_unregistered_nb); 1751 1752 for (i = 0; i < lr->num_lines; i++) { 1753 line = &lr->lines[i]; 1754 if (!line->desc) 1755 continue; 1756 1757 edge_detector_stop(line); 1758 if (line_has_supinfo(line)) 1759 supinfo_erase(line); 1760 gpiod_free(line->desc); 1761 } 1762 kfifo_free(&lr->events); 1763 kfree(lr->label); 1764 gpio_device_put(lr->gdev); 1765 kfree(lr); 1766 } 1767 1768 static int linereq_release(struct inode *inode, struct file *file) 1769 { 1770 struct linereq *lr = file->private_data; 1771 1772 linereq_free(lr); 1773 return 0; 1774 } 1775 1776 #ifdef CONFIG_PROC_FS 1777 static void linereq_show_fdinfo(struct seq_file *out, struct file *file) 1778 { 1779 struct linereq *lr = file->private_data; 1780 struct device *dev = &lr->gdev->dev; 1781 u16 i; 1782 1783 seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev)); 1784 1785 for (i = 0; i < lr->num_lines; i++) 1786 seq_printf(out, "gpio-line:\t%d\n", 1787 gpio_chip_hwgpio(lr->lines[i].desc)); 1788 } 1789 #endif 1790 1791 static const struct file_operations line_fileops = { 1792 .release = linereq_release, 1793 .read = linereq_read, 1794 .poll = linereq_poll, 1795 .owner = THIS_MODULE, 1796 .llseek = noop_llseek, 1797 .unlocked_ioctl = linereq_ioctl, 1798 #ifdef CONFIG_COMPAT 1799 .compat_ioctl = linereq_ioctl_compat, 1800 #endif 1801 #ifdef CONFIG_PROC_FS 1802 .show_fdinfo = linereq_show_fdinfo, 1803 #endif 1804 }; 1805 1806 static int linereq_create(struct gpio_device *gdev, void __user *ip) 1807 { 1808 struct gpio_v2_line_request ulr; 1809 struct gpio_v2_line_config *lc; 1810 struct linereq *lr; 1811 struct file *file; 1812 u64 flags, edflags; 1813 unsigned int i; 1814 int fd, ret; 1815 1816 if (copy_from_user(&ulr, ip, sizeof(ulr))) 1817 return -EFAULT; 1818 1819 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX)) 1820 return -EINVAL; 1821 1822 if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding))) 1823 return -EINVAL; 1824 1825 lc = &ulr.config; 1826 ret = gpio_v2_line_config_validate(lc, ulr.num_lines); 1827 if (ret) 1828 return ret; 1829 1830 lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL); 1831 if (!lr) 1832 return -ENOMEM; 1833 1834 lr->gdev = gpio_device_get(gdev); 1835 1836 for (i = 0; i < ulr.num_lines; i++) { 1837 lr->lines[i].req = lr; 1838 WRITE_ONCE(lr->lines[i].sw_debounced, 0); 1839 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func); 1840 } 1841 1842 if (ulr.consumer[0] != '\0') { 1843 /* label is only initialized if consumer is set */ 1844 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1, 1845 GFP_KERNEL); 1846 if (!lr->label) { 1847 ret = -ENOMEM; 1848 goto out_free_linereq; 1849 } 1850 } 1851 1852 mutex_init(&lr->config_mutex); 1853 init_waitqueue_head(&lr->wait); 1854 lr->event_buffer_size = ulr.event_buffer_size; 1855 if (lr->event_buffer_size == 0) 1856 lr->event_buffer_size = ulr.num_lines * 16; 1857 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16) 1858 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16; 1859 1860 atomic_set(&lr->seqno, 0); 1861 lr->num_lines = ulr.num_lines; 1862 1863 /* Request each GPIO */ 1864 for (i = 0; i < ulr.num_lines; i++) { 1865 u32 offset = ulr.offsets[i]; 1866 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset); 1867 1868 if (IS_ERR(desc)) { 1869 ret = PTR_ERR(desc); 1870 goto out_free_linereq; 1871 } 1872 1873 ret = gpiod_request_user(desc, lr->label); 1874 if (ret) 1875 goto out_free_linereq; 1876 1877 lr->lines[i].desc = desc; 1878 flags = gpio_v2_line_config_flags(lc, i); 1879 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 1880 1881 ret = gpiod_set_transitory(desc, false); 1882 if (ret < 0) 1883 goto out_free_linereq; 1884 1885 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS; 1886 /* 1887 * Lines have to be requested explicitly for input 1888 * or output, else the line will be treated "as is". 1889 */ 1890 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 1891 int val = gpio_v2_line_config_output_value(lc, i); 1892 1893 ret = gpiod_direction_output(desc, val); 1894 if (ret) 1895 goto out_free_linereq; 1896 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 1897 ret = gpiod_direction_input(desc); 1898 if (ret) 1899 goto out_free_linereq; 1900 1901 ret = edge_detector_setup(&lr->lines[i], lc, i, 1902 edflags); 1903 if (ret) 1904 goto out_free_linereq; 1905 } 1906 1907 lr->lines[i].edflags = edflags; 1908 1909 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED); 1910 1911 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 1912 offset); 1913 } 1914 1915 lr->device_unregistered_nb.notifier_call = linereq_unregistered_notify; 1916 ret = blocking_notifier_chain_register(&gdev->device_notifier, 1917 &lr->device_unregistered_nb); 1918 if (ret) 1919 goto out_free_linereq; 1920 1921 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 1922 if (fd < 0) { 1923 ret = fd; 1924 goto out_free_linereq; 1925 } 1926 1927 file = anon_inode_getfile("gpio-line", &line_fileops, lr, 1928 O_RDONLY | O_CLOEXEC); 1929 if (IS_ERR(file)) { 1930 ret = PTR_ERR(file); 1931 goto out_put_unused_fd; 1932 } 1933 1934 ulr.fd = fd; 1935 if (copy_to_user(ip, &ulr, sizeof(ulr))) { 1936 /* 1937 * fput() will trigger the release() callback, so do not go onto 1938 * the regular error cleanup path here. 1939 */ 1940 fput(file); 1941 put_unused_fd(fd); 1942 return -EFAULT; 1943 } 1944 1945 fd_install(fd, file); 1946 1947 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 1948 lr->num_lines); 1949 1950 return 0; 1951 1952 out_put_unused_fd: 1953 put_unused_fd(fd); 1954 out_free_linereq: 1955 linereq_free(lr); 1956 return ret; 1957 } 1958 1959 #ifdef CONFIG_GPIO_CDEV_V1 1960 1961 /* 1962 * GPIO line event management 1963 */ 1964 1965 /** 1966 * struct lineevent_state - contains the state of a userspace event 1967 * @gdev: the GPIO device the event pertains to 1968 * @label: consumer label used to tag descriptors 1969 * @desc: the GPIO descriptor held by this event 1970 * @eflags: the event flags this line was requested with 1971 * @irq: the interrupt that trigger in response to events on this GPIO 1972 * @wait: wait queue that handles blocking reads of events 1973 * @device_unregistered_nb: notifier block for receiving gdev unregister events 1974 * @events: KFIFO for the GPIO events 1975 * @timestamp: cache for the timestamp storing it between hardirq 1976 * and IRQ thread, used to bring the timestamp close to the actual 1977 * event 1978 */ 1979 struct lineevent_state { 1980 struct gpio_device *gdev; 1981 const char *label; 1982 struct gpio_desc *desc; 1983 u32 eflags; 1984 int irq; 1985 wait_queue_head_t wait; 1986 struct notifier_block device_unregistered_nb; 1987 DECLARE_KFIFO(events, struct gpioevent_data, 16); 1988 u64 timestamp; 1989 }; 1990 1991 #define GPIOEVENT_REQUEST_VALID_FLAGS \ 1992 (GPIOEVENT_REQUEST_RISING_EDGE | \ 1993 GPIOEVENT_REQUEST_FALLING_EDGE) 1994 1995 static __poll_t lineevent_poll_unlocked(struct file *file, 1996 struct poll_table_struct *wait) 1997 { 1998 struct lineevent_state *le = file->private_data; 1999 __poll_t events = 0; 2000 2001 if (!le->gdev->chip) 2002 return EPOLLHUP | EPOLLERR; 2003 2004 poll_wait(file, &le->wait, wait); 2005 2006 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock)) 2007 events = EPOLLIN | EPOLLRDNORM; 2008 2009 return events; 2010 } 2011 2012 static __poll_t lineevent_poll(struct file *file, 2013 struct poll_table_struct *wait) 2014 { 2015 struct lineevent_state *le = file->private_data; 2016 2017 return call_poll_locked(file, wait, le->gdev, lineevent_poll_unlocked); 2018 } 2019 2020 static int lineevent_unregistered_notify(struct notifier_block *nb, 2021 unsigned long action, void *data) 2022 { 2023 struct lineevent_state *le = container_of(nb, struct lineevent_state, 2024 device_unregistered_nb); 2025 2026 wake_up_poll(&le->wait, EPOLLIN | EPOLLERR); 2027 2028 return NOTIFY_OK; 2029 } 2030 2031 struct compat_gpioeevent_data { 2032 compat_u64 timestamp; 2033 u32 id; 2034 }; 2035 2036 static ssize_t lineevent_read_unlocked(struct file *file, char __user *buf, 2037 size_t count, loff_t *f_ps) 2038 { 2039 struct lineevent_state *le = file->private_data; 2040 struct gpioevent_data ge; 2041 ssize_t bytes_read = 0; 2042 ssize_t ge_size; 2043 int ret; 2044 2045 if (!le->gdev->chip) 2046 return -ENODEV; 2047 2048 /* 2049 * When compatible system call is being used the struct gpioevent_data, 2050 * in case of at least ia32, has different size due to the alignment 2051 * differences. Because we have first member 64 bits followed by one of 2052 * 32 bits there is no gap between them. The only difference is the 2053 * padding at the end of the data structure. Hence, we calculate the 2054 * actual sizeof() and pass this as an argument to copy_to_user() to 2055 * drop unneeded bytes from the output. 2056 */ 2057 if (compat_need_64bit_alignment_fixup()) 2058 ge_size = sizeof(struct compat_gpioeevent_data); 2059 else 2060 ge_size = sizeof(struct gpioevent_data); 2061 if (count < ge_size) 2062 return -EINVAL; 2063 2064 do { 2065 spin_lock(&le->wait.lock); 2066 if (kfifo_is_empty(&le->events)) { 2067 if (bytes_read) { 2068 spin_unlock(&le->wait.lock); 2069 return bytes_read; 2070 } 2071 2072 if (file->f_flags & O_NONBLOCK) { 2073 spin_unlock(&le->wait.lock); 2074 return -EAGAIN; 2075 } 2076 2077 ret = wait_event_interruptible_locked(le->wait, 2078 !kfifo_is_empty(&le->events)); 2079 if (ret) { 2080 spin_unlock(&le->wait.lock); 2081 return ret; 2082 } 2083 } 2084 2085 ret = kfifo_out(&le->events, &ge, 1); 2086 spin_unlock(&le->wait.lock); 2087 if (ret != 1) { 2088 /* 2089 * This should never happen - we were holding the lock 2090 * from the moment we learned the fifo is no longer 2091 * empty until now. 2092 */ 2093 ret = -EIO; 2094 break; 2095 } 2096 2097 if (copy_to_user(buf + bytes_read, &ge, ge_size)) 2098 return -EFAULT; 2099 bytes_read += ge_size; 2100 } while (count >= bytes_read + ge_size); 2101 2102 return bytes_read; 2103 } 2104 2105 static ssize_t lineevent_read(struct file *file, char __user *buf, 2106 size_t count, loff_t *f_ps) 2107 { 2108 struct lineevent_state *le = file->private_data; 2109 2110 return call_read_locked(file, buf, count, f_ps, le->gdev, 2111 lineevent_read_unlocked); 2112 } 2113 2114 static void lineevent_free(struct lineevent_state *le) 2115 { 2116 if (le->device_unregistered_nb.notifier_call) 2117 blocking_notifier_chain_unregister(&le->gdev->device_notifier, 2118 &le->device_unregistered_nb); 2119 if (le->irq) 2120 free_irq_label(free_irq(le->irq, le)); 2121 if (le->desc) 2122 gpiod_free(le->desc); 2123 kfree(le->label); 2124 gpio_device_put(le->gdev); 2125 kfree(le); 2126 } 2127 2128 static int lineevent_release(struct inode *inode, struct file *file) 2129 { 2130 lineevent_free(file->private_data); 2131 return 0; 2132 } 2133 2134 static long lineevent_ioctl_unlocked(struct file *file, unsigned int cmd, 2135 unsigned long arg) 2136 { 2137 struct lineevent_state *le = file->private_data; 2138 void __user *ip = (void __user *)arg; 2139 struct gpiohandle_data ghd; 2140 2141 if (!le->gdev->chip) 2142 return -ENODEV; 2143 2144 /* 2145 * We can get the value for an event line but not set it, 2146 * because it is input by definition. 2147 */ 2148 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { 2149 int val; 2150 2151 memset(&ghd, 0, sizeof(ghd)); 2152 2153 val = gpiod_get_value_cansleep(le->desc); 2154 if (val < 0) 2155 return val; 2156 ghd.values[0] = val; 2157 2158 if (copy_to_user(ip, &ghd, sizeof(ghd))) 2159 return -EFAULT; 2160 2161 return 0; 2162 } 2163 return -EINVAL; 2164 } 2165 2166 static long lineevent_ioctl(struct file *file, unsigned int cmd, 2167 unsigned long arg) 2168 { 2169 struct lineevent_state *le = file->private_data; 2170 2171 return call_ioctl_locked(file, cmd, arg, le->gdev, 2172 lineevent_ioctl_unlocked); 2173 } 2174 2175 #ifdef CONFIG_COMPAT 2176 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd, 2177 unsigned long arg) 2178 { 2179 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 2180 } 2181 #endif 2182 2183 static const struct file_operations lineevent_fileops = { 2184 .release = lineevent_release, 2185 .read = lineevent_read, 2186 .poll = lineevent_poll, 2187 .owner = THIS_MODULE, 2188 .llseek = noop_llseek, 2189 .unlocked_ioctl = lineevent_ioctl, 2190 #ifdef CONFIG_COMPAT 2191 .compat_ioctl = lineevent_ioctl_compat, 2192 #endif 2193 }; 2194 2195 static irqreturn_t lineevent_irq_thread(int irq, void *p) 2196 { 2197 struct lineevent_state *le = p; 2198 struct gpioevent_data ge; 2199 int ret; 2200 2201 /* Do not leak kernel stack to userspace */ 2202 memset(&ge, 0, sizeof(ge)); 2203 2204 /* 2205 * We may be running from a nested threaded interrupt in which case 2206 * we didn't get the timestamp from lineevent_irq_handler(). 2207 */ 2208 if (!le->timestamp) 2209 ge.timestamp = ktime_get_ns(); 2210 else 2211 ge.timestamp = le->timestamp; 2212 2213 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE 2214 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 2215 int level = gpiod_get_value_cansleep(le->desc); 2216 2217 if (level) 2218 /* Emit low-to-high event */ 2219 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 2220 else 2221 /* Emit high-to-low event */ 2222 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 2223 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) { 2224 /* Emit low-to-high event */ 2225 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 2226 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 2227 /* Emit high-to-low event */ 2228 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 2229 } else { 2230 return IRQ_NONE; 2231 } 2232 2233 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge, 2234 1, &le->wait.lock); 2235 if (ret) 2236 wake_up_poll(&le->wait, EPOLLIN); 2237 else 2238 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 2239 2240 return IRQ_HANDLED; 2241 } 2242 2243 static irqreturn_t lineevent_irq_handler(int irq, void *p) 2244 { 2245 struct lineevent_state *le = p; 2246 2247 /* 2248 * Just store the timestamp in hardirq context so we get it as 2249 * close in time as possible to the actual event. 2250 */ 2251 le->timestamp = ktime_get_ns(); 2252 2253 return IRQ_WAKE_THREAD; 2254 } 2255 2256 static int lineevent_create(struct gpio_device *gdev, void __user *ip) 2257 { 2258 struct gpioevent_request eventreq; 2259 struct lineevent_state *le; 2260 struct gpio_desc *desc; 2261 struct file *file; 2262 u32 offset; 2263 u32 lflags; 2264 u32 eflags; 2265 int fd; 2266 int ret; 2267 int irq, irqflags = 0; 2268 char *label; 2269 2270 if (copy_from_user(&eventreq, ip, sizeof(eventreq))) 2271 return -EFAULT; 2272 2273 offset = eventreq.lineoffset; 2274 lflags = eventreq.handleflags; 2275 eflags = eventreq.eventflags; 2276 2277 desc = gpiochip_get_desc(gdev->chip, offset); 2278 if (IS_ERR(desc)) 2279 return PTR_ERR(desc); 2280 2281 /* Return an error if a unknown flag is set */ 2282 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) || 2283 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS)) 2284 return -EINVAL; 2285 2286 /* This is just wrong: we don't look for events on output lines */ 2287 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) || 2288 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 2289 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 2290 return -EINVAL; 2291 2292 /* Only one bias flag can be set. */ 2293 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 2294 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 2295 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 2296 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 2297 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 2298 return -EINVAL; 2299 2300 le = kzalloc(sizeof(*le), GFP_KERNEL); 2301 if (!le) 2302 return -ENOMEM; 2303 le->gdev = gpio_device_get(gdev); 2304 2305 if (eventreq.consumer_label[0] != '\0') { 2306 /* label is only initialized if consumer_label is set */ 2307 le->label = kstrndup(eventreq.consumer_label, 2308 sizeof(eventreq.consumer_label) - 1, 2309 GFP_KERNEL); 2310 if (!le->label) { 2311 ret = -ENOMEM; 2312 goto out_free_le; 2313 } 2314 } 2315 2316 ret = gpiod_request_user(desc, le->label); 2317 if (ret) 2318 goto out_free_le; 2319 le->desc = desc; 2320 le->eflags = eflags; 2321 2322 linehandle_flags_to_desc_flags(lflags, &desc->flags); 2323 2324 ret = gpiod_direction_input(desc); 2325 if (ret) 2326 goto out_free_le; 2327 2328 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED); 2329 2330 irq = gpiod_to_irq(desc); 2331 if (irq <= 0) { 2332 ret = -ENODEV; 2333 goto out_free_le; 2334 } 2335 2336 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE) 2337 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 2338 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 2339 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE) 2340 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 2341 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 2342 irqflags |= IRQF_ONESHOT; 2343 2344 INIT_KFIFO(le->events); 2345 init_waitqueue_head(&le->wait); 2346 2347 le->device_unregistered_nb.notifier_call = lineevent_unregistered_notify; 2348 ret = blocking_notifier_chain_register(&gdev->device_notifier, 2349 &le->device_unregistered_nb); 2350 if (ret) 2351 goto out_free_le; 2352 2353 label = make_irq_label(le->label); 2354 if (IS_ERR(label)) { 2355 ret = PTR_ERR(label); 2356 goto out_free_le; 2357 } 2358 2359 /* Request a thread to read the events */ 2360 ret = request_threaded_irq(irq, 2361 lineevent_irq_handler, 2362 lineevent_irq_thread, 2363 irqflags, 2364 label, 2365 le); 2366 if (ret) { 2367 free_irq_label(label); 2368 goto out_free_le; 2369 } 2370 2371 le->irq = irq; 2372 2373 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 2374 if (fd < 0) { 2375 ret = fd; 2376 goto out_free_le; 2377 } 2378 2379 file = anon_inode_getfile("gpio-event", 2380 &lineevent_fileops, 2381 le, 2382 O_RDONLY | O_CLOEXEC); 2383 if (IS_ERR(file)) { 2384 ret = PTR_ERR(file); 2385 goto out_put_unused_fd; 2386 } 2387 2388 eventreq.fd = fd; 2389 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) { 2390 /* 2391 * fput() will trigger the release() callback, so do not go onto 2392 * the regular error cleanup path here. 2393 */ 2394 fput(file); 2395 put_unused_fd(fd); 2396 return -EFAULT; 2397 } 2398 2399 fd_install(fd, file); 2400 2401 return 0; 2402 2403 out_put_unused_fd: 2404 put_unused_fd(fd); 2405 out_free_le: 2406 lineevent_free(le); 2407 return ret; 2408 } 2409 2410 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2, 2411 struct gpioline_info *info_v1) 2412 { 2413 u64 flagsv2 = info_v2->flags; 2414 2415 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name)); 2416 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer)); 2417 info_v1->line_offset = info_v2->offset; 2418 info_v1->flags = 0; 2419 2420 if (flagsv2 & GPIO_V2_LINE_FLAG_USED) 2421 info_v1->flags |= GPIOLINE_FLAG_KERNEL; 2422 2423 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT) 2424 info_v1->flags |= GPIOLINE_FLAG_IS_OUT; 2425 2426 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 2427 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW; 2428 2429 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN) 2430 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN; 2431 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE) 2432 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE; 2433 2434 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP) 2435 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP; 2436 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) 2437 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN; 2438 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED) 2439 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE; 2440 } 2441 2442 static void gpio_v2_line_info_changed_to_v1( 2443 struct gpio_v2_line_info_changed *lic_v2, 2444 struct gpioline_info_changed *lic_v1) 2445 { 2446 memset(lic_v1, 0, sizeof(*lic_v1)); 2447 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info); 2448 lic_v1->timestamp = lic_v2->timestamp_ns; 2449 lic_v1->event_type = lic_v2->event_type; 2450 } 2451 2452 #endif /* CONFIG_GPIO_CDEV_V1 */ 2453 2454 static void gpio_desc_to_lineinfo(struct gpio_desc *desc, 2455 struct gpio_v2_line_info *info) 2456 { 2457 struct gpio_chip *gc = desc->gdev->chip; 2458 bool ok_for_pinctrl; 2459 unsigned long flags; 2460 2461 memset(info, 0, sizeof(*info)); 2462 info->offset = gpio_chip_hwgpio(desc); 2463 2464 /* 2465 * This function takes a mutex so we must check this before taking 2466 * the spinlock. 2467 * 2468 * FIXME: find a non-racy way to retrieve this information. Maybe a 2469 * lock common to both frameworks? 2470 */ 2471 ok_for_pinctrl = 2472 pinctrl_gpio_can_use_line(gc->base + info->offset); 2473 2474 spin_lock_irqsave(&gpio_lock, flags); 2475 2476 if (desc->name) 2477 strscpy(info->name, desc->name, sizeof(info->name)); 2478 2479 if (desc->label) 2480 strscpy(info->consumer, desc->label, sizeof(info->consumer)); 2481 2482 /* 2483 * Userspace only need to know that the kernel is using this GPIO so 2484 * it can't use it. 2485 */ 2486 info->flags = 0; 2487 if (test_bit(FLAG_REQUESTED, &desc->flags) || 2488 test_bit(FLAG_IS_HOGGED, &desc->flags) || 2489 test_bit(FLAG_USED_AS_IRQ, &desc->flags) || 2490 test_bit(FLAG_EXPORT, &desc->flags) || 2491 test_bit(FLAG_SYSFS, &desc->flags) || 2492 !gpiochip_line_is_valid(gc, info->offset) || 2493 !ok_for_pinctrl) 2494 info->flags |= GPIO_V2_LINE_FLAG_USED; 2495 2496 if (test_bit(FLAG_IS_OUT, &desc->flags)) 2497 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT; 2498 else 2499 info->flags |= GPIO_V2_LINE_FLAG_INPUT; 2500 2501 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) 2502 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW; 2503 2504 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) 2505 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN; 2506 if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) 2507 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE; 2508 2509 if (test_bit(FLAG_BIAS_DISABLE, &desc->flags)) 2510 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED; 2511 if (test_bit(FLAG_PULL_DOWN, &desc->flags)) 2512 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN; 2513 if (test_bit(FLAG_PULL_UP, &desc->flags)) 2514 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP; 2515 2516 if (test_bit(FLAG_EDGE_RISING, &desc->flags)) 2517 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING; 2518 if (test_bit(FLAG_EDGE_FALLING, &desc->flags)) 2519 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING; 2520 2521 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &desc->flags)) 2522 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME; 2523 else if (test_bit(FLAG_EVENT_CLOCK_HTE, &desc->flags)) 2524 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE; 2525 2526 spin_unlock_irqrestore(&gpio_lock, flags); 2527 } 2528 2529 struct gpio_chardev_data { 2530 struct gpio_device *gdev; 2531 wait_queue_head_t wait; 2532 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32); 2533 struct notifier_block lineinfo_changed_nb; 2534 struct notifier_block device_unregistered_nb; 2535 unsigned long *watched_lines; 2536 #ifdef CONFIG_GPIO_CDEV_V1 2537 atomic_t watch_abi_version; 2538 #endif 2539 }; 2540 2541 static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip) 2542 { 2543 struct gpio_device *gdev = cdev->gdev; 2544 struct gpiochip_info chipinfo; 2545 2546 memset(&chipinfo, 0, sizeof(chipinfo)); 2547 2548 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name)); 2549 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label)); 2550 chipinfo.lines = gdev->ngpio; 2551 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo))) 2552 return -EFAULT; 2553 return 0; 2554 } 2555 2556 #ifdef CONFIG_GPIO_CDEV_V1 2557 /* 2558 * returns 0 if the versions match, else the previously selected ABI version 2559 */ 2560 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata, 2561 unsigned int version) 2562 { 2563 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version); 2564 2565 if (abiv == version) 2566 return 0; 2567 2568 return abiv; 2569 } 2570 2571 static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip, 2572 bool watch) 2573 { 2574 struct gpio_desc *desc; 2575 struct gpioline_info lineinfo; 2576 struct gpio_v2_line_info lineinfo_v2; 2577 2578 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2579 return -EFAULT; 2580 2581 /* this doubles as a range check on line_offset */ 2582 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset); 2583 if (IS_ERR(desc)) 2584 return PTR_ERR(desc); 2585 2586 if (watch) { 2587 if (lineinfo_ensure_abi_version(cdev, 1)) 2588 return -EPERM; 2589 2590 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines)) 2591 return -EBUSY; 2592 } 2593 2594 gpio_desc_to_lineinfo(desc, &lineinfo_v2); 2595 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); 2596 2597 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2598 if (watch) 2599 clear_bit(lineinfo.line_offset, cdev->watched_lines); 2600 return -EFAULT; 2601 } 2602 2603 return 0; 2604 } 2605 #endif 2606 2607 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, 2608 bool watch) 2609 { 2610 struct gpio_desc *desc; 2611 struct gpio_v2_line_info lineinfo; 2612 2613 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 2614 return -EFAULT; 2615 2616 if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding))) 2617 return -EINVAL; 2618 2619 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset); 2620 if (IS_ERR(desc)) 2621 return PTR_ERR(desc); 2622 2623 if (watch) { 2624 #ifdef CONFIG_GPIO_CDEV_V1 2625 if (lineinfo_ensure_abi_version(cdev, 2)) 2626 return -EPERM; 2627 #endif 2628 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines)) 2629 return -EBUSY; 2630 } 2631 gpio_desc_to_lineinfo(desc, &lineinfo); 2632 supinfo_to_lineinfo(desc, &lineinfo); 2633 2634 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 2635 if (watch) 2636 clear_bit(lineinfo.offset, cdev->watched_lines); 2637 return -EFAULT; 2638 } 2639 2640 return 0; 2641 } 2642 2643 static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip) 2644 { 2645 __u32 offset; 2646 2647 if (copy_from_user(&offset, ip, sizeof(offset))) 2648 return -EFAULT; 2649 2650 if (offset >= cdev->gdev->ngpio) 2651 return -EINVAL; 2652 2653 if (!test_and_clear_bit(offset, cdev->watched_lines)) 2654 return -EBUSY; 2655 2656 return 0; 2657 } 2658 2659 static long gpio_ioctl_unlocked(struct file *file, unsigned int cmd, unsigned long arg) 2660 { 2661 struct gpio_chardev_data *cdev = file->private_data; 2662 struct gpio_device *gdev = cdev->gdev; 2663 void __user *ip = (void __user *)arg; 2664 2665 /* We fail any subsequent ioctl():s when the chip is gone */ 2666 if (!gdev->chip) 2667 return -ENODEV; 2668 2669 /* Fill in the struct and pass to userspace */ 2670 switch (cmd) { 2671 case GPIO_GET_CHIPINFO_IOCTL: 2672 return chipinfo_get(cdev, ip); 2673 #ifdef CONFIG_GPIO_CDEV_V1 2674 case GPIO_GET_LINEHANDLE_IOCTL: 2675 return linehandle_create(gdev, ip); 2676 case GPIO_GET_LINEEVENT_IOCTL: 2677 return lineevent_create(gdev, ip); 2678 case GPIO_GET_LINEINFO_IOCTL: 2679 return lineinfo_get_v1(cdev, ip, false); 2680 case GPIO_GET_LINEINFO_WATCH_IOCTL: 2681 return lineinfo_get_v1(cdev, ip, true); 2682 #endif /* CONFIG_GPIO_CDEV_V1 */ 2683 case GPIO_V2_GET_LINEINFO_IOCTL: 2684 return lineinfo_get(cdev, ip, false); 2685 case GPIO_V2_GET_LINEINFO_WATCH_IOCTL: 2686 return lineinfo_get(cdev, ip, true); 2687 case GPIO_V2_GET_LINE_IOCTL: 2688 return linereq_create(gdev, ip); 2689 case GPIO_GET_LINEINFO_UNWATCH_IOCTL: 2690 return lineinfo_unwatch(cdev, ip); 2691 default: 2692 return -EINVAL; 2693 } 2694 } 2695 2696 /* 2697 * gpio_ioctl() - ioctl handler for the GPIO chardev 2698 */ 2699 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 2700 { 2701 struct gpio_chardev_data *cdev = file->private_data; 2702 2703 return call_ioctl_locked(file, cmd, arg, cdev->gdev, 2704 gpio_ioctl_unlocked); 2705 } 2706 2707 #ifdef CONFIG_COMPAT 2708 static long gpio_ioctl_compat(struct file *file, unsigned int cmd, 2709 unsigned long arg) 2710 { 2711 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 2712 } 2713 #endif 2714 2715 static int lineinfo_changed_notify(struct notifier_block *nb, 2716 unsigned long action, void *data) 2717 { 2718 struct gpio_chardev_data *cdev = 2719 container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb); 2720 struct gpio_v2_line_info_changed chg; 2721 struct gpio_desc *desc = data; 2722 int ret; 2723 2724 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines)) 2725 return NOTIFY_DONE; 2726 2727 memset(&chg, 0, sizeof(chg)); 2728 chg.event_type = action; 2729 chg.timestamp_ns = ktime_get_ns(); 2730 gpio_desc_to_lineinfo(desc, &chg.info); 2731 supinfo_to_lineinfo(desc, &chg.info); 2732 2733 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock); 2734 if (ret) 2735 wake_up_poll(&cdev->wait, EPOLLIN); 2736 else 2737 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n"); 2738 2739 return NOTIFY_OK; 2740 } 2741 2742 static int gpio_device_unregistered_notify(struct notifier_block *nb, 2743 unsigned long action, void *data) 2744 { 2745 struct gpio_chardev_data *cdev = container_of(nb, 2746 struct gpio_chardev_data, 2747 device_unregistered_nb); 2748 2749 wake_up_poll(&cdev->wait, EPOLLIN | EPOLLERR); 2750 2751 return NOTIFY_OK; 2752 } 2753 2754 static __poll_t lineinfo_watch_poll_unlocked(struct file *file, 2755 struct poll_table_struct *pollt) 2756 { 2757 struct gpio_chardev_data *cdev = file->private_data; 2758 __poll_t events = 0; 2759 2760 if (!cdev->gdev->chip) 2761 return EPOLLHUP | EPOLLERR; 2762 2763 poll_wait(file, &cdev->wait, pollt); 2764 2765 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events, 2766 &cdev->wait.lock)) 2767 events = EPOLLIN | EPOLLRDNORM; 2768 2769 return events; 2770 } 2771 2772 static __poll_t lineinfo_watch_poll(struct file *file, 2773 struct poll_table_struct *pollt) 2774 { 2775 struct gpio_chardev_data *cdev = file->private_data; 2776 2777 return call_poll_locked(file, pollt, cdev->gdev, 2778 lineinfo_watch_poll_unlocked); 2779 } 2780 2781 static ssize_t lineinfo_watch_read_unlocked(struct file *file, char __user *buf, 2782 size_t count, loff_t *off) 2783 { 2784 struct gpio_chardev_data *cdev = file->private_data; 2785 struct gpio_v2_line_info_changed event; 2786 ssize_t bytes_read = 0; 2787 int ret; 2788 size_t event_size; 2789 2790 if (!cdev->gdev->chip) 2791 return -ENODEV; 2792 2793 #ifndef CONFIG_GPIO_CDEV_V1 2794 event_size = sizeof(struct gpio_v2_line_info_changed); 2795 if (count < event_size) 2796 return -EINVAL; 2797 #endif 2798 2799 do { 2800 spin_lock(&cdev->wait.lock); 2801 if (kfifo_is_empty(&cdev->events)) { 2802 if (bytes_read) { 2803 spin_unlock(&cdev->wait.lock); 2804 return bytes_read; 2805 } 2806 2807 if (file->f_flags & O_NONBLOCK) { 2808 spin_unlock(&cdev->wait.lock); 2809 return -EAGAIN; 2810 } 2811 2812 ret = wait_event_interruptible_locked(cdev->wait, 2813 !kfifo_is_empty(&cdev->events)); 2814 if (ret) { 2815 spin_unlock(&cdev->wait.lock); 2816 return ret; 2817 } 2818 } 2819 #ifdef CONFIG_GPIO_CDEV_V1 2820 /* must be after kfifo check so watch_abi_version is set */ 2821 if (atomic_read(&cdev->watch_abi_version) == 2) 2822 event_size = sizeof(struct gpio_v2_line_info_changed); 2823 else 2824 event_size = sizeof(struct gpioline_info_changed); 2825 if (count < event_size) { 2826 spin_unlock(&cdev->wait.lock); 2827 return -EINVAL; 2828 } 2829 #endif 2830 ret = kfifo_out(&cdev->events, &event, 1); 2831 spin_unlock(&cdev->wait.lock); 2832 if (ret != 1) { 2833 ret = -EIO; 2834 break; 2835 /* We should never get here. See lineevent_read(). */ 2836 } 2837 2838 #ifdef CONFIG_GPIO_CDEV_V1 2839 if (event_size == sizeof(struct gpio_v2_line_info_changed)) { 2840 if (copy_to_user(buf + bytes_read, &event, event_size)) 2841 return -EFAULT; 2842 } else { 2843 struct gpioline_info_changed event_v1; 2844 2845 gpio_v2_line_info_changed_to_v1(&event, &event_v1); 2846 if (copy_to_user(buf + bytes_read, &event_v1, 2847 event_size)) 2848 return -EFAULT; 2849 } 2850 #else 2851 if (copy_to_user(buf + bytes_read, &event, event_size)) 2852 return -EFAULT; 2853 #endif 2854 bytes_read += event_size; 2855 } while (count >= bytes_read + sizeof(event)); 2856 2857 return bytes_read; 2858 } 2859 2860 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, 2861 size_t count, loff_t *off) 2862 { 2863 struct gpio_chardev_data *cdev = file->private_data; 2864 2865 return call_read_locked(file, buf, count, off, cdev->gdev, 2866 lineinfo_watch_read_unlocked); 2867 } 2868 2869 /** 2870 * gpio_chrdev_open() - open the chardev for ioctl operations 2871 * @inode: inode for this chardev 2872 * @file: file struct for storing private data 2873 * Returns 0 on success 2874 */ 2875 static int gpio_chrdev_open(struct inode *inode, struct file *file) 2876 { 2877 struct gpio_device *gdev = container_of(inode->i_cdev, 2878 struct gpio_device, chrdev); 2879 struct gpio_chardev_data *cdev; 2880 int ret = -ENOMEM; 2881 2882 down_read(&gdev->sem); 2883 2884 /* Fail on open if the backing gpiochip is gone */ 2885 if (!gdev->chip) { 2886 ret = -ENODEV; 2887 goto out_unlock; 2888 } 2889 2890 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL); 2891 if (!cdev) 2892 goto out_unlock; 2893 2894 cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL); 2895 if (!cdev->watched_lines) 2896 goto out_free_cdev; 2897 2898 init_waitqueue_head(&cdev->wait); 2899 INIT_KFIFO(cdev->events); 2900 cdev->gdev = gpio_device_get(gdev); 2901 2902 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify; 2903 ret = blocking_notifier_chain_register(&gdev->line_state_notifier, 2904 &cdev->lineinfo_changed_nb); 2905 if (ret) 2906 goto out_free_bitmap; 2907 2908 cdev->device_unregistered_nb.notifier_call = 2909 gpio_device_unregistered_notify; 2910 ret = blocking_notifier_chain_register(&gdev->device_notifier, 2911 &cdev->device_unregistered_nb); 2912 if (ret) 2913 goto out_unregister_line_notifier; 2914 2915 file->private_data = cdev; 2916 2917 ret = nonseekable_open(inode, file); 2918 if (ret) 2919 goto out_unregister_device_notifier; 2920 2921 up_read(&gdev->sem); 2922 2923 return ret; 2924 2925 out_unregister_device_notifier: 2926 blocking_notifier_chain_unregister(&gdev->device_notifier, 2927 &cdev->device_unregistered_nb); 2928 out_unregister_line_notifier: 2929 blocking_notifier_chain_unregister(&gdev->line_state_notifier, 2930 &cdev->lineinfo_changed_nb); 2931 out_free_bitmap: 2932 gpio_device_put(gdev); 2933 bitmap_free(cdev->watched_lines); 2934 out_free_cdev: 2935 kfree(cdev); 2936 out_unlock: 2937 up_read(&gdev->sem); 2938 return ret; 2939 } 2940 2941 /** 2942 * gpio_chrdev_release() - close chardev after ioctl operations 2943 * @inode: inode for this chardev 2944 * @file: file struct for storing private data 2945 * Returns 0 on success 2946 */ 2947 static int gpio_chrdev_release(struct inode *inode, struct file *file) 2948 { 2949 struct gpio_chardev_data *cdev = file->private_data; 2950 struct gpio_device *gdev = cdev->gdev; 2951 2952 blocking_notifier_chain_unregister(&gdev->device_notifier, 2953 &cdev->device_unregistered_nb); 2954 blocking_notifier_chain_unregister(&gdev->line_state_notifier, 2955 &cdev->lineinfo_changed_nb); 2956 bitmap_free(cdev->watched_lines); 2957 gpio_device_put(gdev); 2958 kfree(cdev); 2959 2960 return 0; 2961 } 2962 2963 static const struct file_operations gpio_fileops = { 2964 .release = gpio_chrdev_release, 2965 .open = gpio_chrdev_open, 2966 .poll = lineinfo_watch_poll, 2967 .read = lineinfo_watch_read, 2968 .owner = THIS_MODULE, 2969 .llseek = no_llseek, 2970 .unlocked_ioctl = gpio_ioctl, 2971 #ifdef CONFIG_COMPAT 2972 .compat_ioctl = gpio_ioctl_compat, 2973 #endif 2974 }; 2975 2976 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt) 2977 { 2978 int ret; 2979 2980 cdev_init(&gdev->chrdev, &gpio_fileops); 2981 gdev->chrdev.owner = THIS_MODULE; 2982 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id); 2983 2984 ret = cdev_device_add(&gdev->chrdev, &gdev->dev); 2985 if (ret) 2986 return ret; 2987 2988 chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n", 2989 MAJOR(devt), gdev->id); 2990 2991 return 0; 2992 } 2993 2994 void gpiolib_cdev_unregister(struct gpio_device *gdev) 2995 { 2996 cdev_device_del(&gdev->chrdev, &gdev->dev); 2997 blocking_notifier_call_chain(&gdev->device_notifier, 0, NULL); 2998 } 2999