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