1 // SPDX-License-Identifier: GPL-2.0 2 3 #include <linux/anon_inodes.h> 4 #include <linux/atomic.h> 5 #include <linux/bitmap.h> 6 #include <linux/build_bug.h> 7 #include <linux/cdev.h> 8 #include <linux/compat.h> 9 #include <linux/device.h> 10 #include <linux/err.h> 11 #include <linux/file.h> 12 #include <linux/gpio.h> 13 #include <linux/gpio/driver.h> 14 #include <linux/interrupt.h> 15 #include <linux/irqreturn.h> 16 #include <linux/kernel.h> 17 #include <linux/kfifo.h> 18 #include <linux/module.h> 19 #include <linux/pinctrl/consumer.h> 20 #include <linux/poll.h> 21 #include <linux/spinlock.h> 22 #include <linux/timekeeping.h> 23 #include <linux/uaccess.h> 24 #include <uapi/linux/gpio.h> 25 26 #include "gpiolib.h" 27 #include "gpiolib-cdev.h" 28 29 /* 30 * Array sizes must ensure 64-bit alignment and not create holes in the 31 * struct packing. 32 */ 33 static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2)); 34 static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8)); 35 36 /* 37 * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility 38 */ 39 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8)); 40 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8)); 41 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8)); 42 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8)); 43 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8)); 44 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8)); 45 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8)); 46 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8)); 47 48 /* Character device interface to GPIO. 49 * 50 * The GPIO character device, /dev/gpiochipN, provides userspace an 51 * interface to gpiolib GPIOs via ioctl()s. 52 */ 53 54 /* 55 * GPIO line handle management 56 */ 57 58 #ifdef CONFIG_GPIO_CDEV_V1 59 /** 60 * struct linehandle_state - contains the state of a userspace handle 61 * @gdev: the GPIO device the handle pertains to 62 * @label: consumer label used to tag descriptors 63 * @descs: the GPIO descriptors held by this handle 64 * @num_descs: the number of descriptors held in the descs array 65 */ 66 struct linehandle_state { 67 struct gpio_device *gdev; 68 const char *label; 69 struct gpio_desc *descs[GPIOHANDLES_MAX]; 70 u32 num_descs; 71 }; 72 73 #define GPIOHANDLE_REQUEST_VALID_FLAGS \ 74 (GPIOHANDLE_REQUEST_INPUT | \ 75 GPIOHANDLE_REQUEST_OUTPUT | \ 76 GPIOHANDLE_REQUEST_ACTIVE_LOW | \ 77 GPIOHANDLE_REQUEST_BIAS_PULL_UP | \ 78 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \ 79 GPIOHANDLE_REQUEST_BIAS_DISABLE | \ 80 GPIOHANDLE_REQUEST_OPEN_DRAIN | \ 81 GPIOHANDLE_REQUEST_OPEN_SOURCE) 82 83 static int linehandle_validate_flags(u32 flags) 84 { 85 /* Return an error if an unknown flag is set */ 86 if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) 87 return -EINVAL; 88 89 /* 90 * Do not allow both INPUT & OUTPUT flags to be set as they are 91 * contradictory. 92 */ 93 if ((flags & GPIOHANDLE_REQUEST_INPUT) && 94 (flags & GPIOHANDLE_REQUEST_OUTPUT)) 95 return -EINVAL; 96 97 /* 98 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If 99 * the hardware actually supports enabling both at the same time the 100 * electrical result would be disastrous. 101 */ 102 if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) && 103 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 104 return -EINVAL; 105 106 /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */ 107 if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) && 108 ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 109 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))) 110 return -EINVAL; 111 112 /* Bias flags only allowed for input or output mode. */ 113 if (!((flags & GPIOHANDLE_REQUEST_INPUT) || 114 (flags & GPIOHANDLE_REQUEST_OUTPUT)) && 115 ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) || 116 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) || 117 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN))) 118 return -EINVAL; 119 120 /* Only one bias flag can be set. */ 121 if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 122 (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 123 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 124 ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 125 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 126 return -EINVAL; 127 128 return 0; 129 } 130 131 static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp) 132 { 133 assign_bit(FLAG_ACTIVE_LOW, flagsp, 134 lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW); 135 assign_bit(FLAG_OPEN_DRAIN, flagsp, 136 lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN); 137 assign_bit(FLAG_OPEN_SOURCE, flagsp, 138 lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE); 139 assign_bit(FLAG_PULL_UP, flagsp, 140 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP); 141 assign_bit(FLAG_PULL_DOWN, flagsp, 142 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN); 143 assign_bit(FLAG_BIAS_DISABLE, flagsp, 144 lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE); 145 } 146 147 static long linehandle_set_config(struct linehandle_state *lh, 148 void __user *ip) 149 { 150 struct gpiohandle_config gcnf; 151 struct gpio_desc *desc; 152 int i, ret; 153 u32 lflags; 154 155 if (copy_from_user(&gcnf, ip, sizeof(gcnf))) 156 return -EFAULT; 157 158 lflags = gcnf.flags; 159 ret = linehandle_validate_flags(lflags); 160 if (ret) 161 return ret; 162 163 for (i = 0; i < lh->num_descs; i++) { 164 desc = lh->descs[i]; 165 linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags); 166 167 /* 168 * Lines have to be requested explicitly for input 169 * or output, else the line will be treated "as is". 170 */ 171 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { 172 int val = !!gcnf.default_values[i]; 173 174 ret = gpiod_direction_output(desc, val); 175 if (ret) 176 return ret; 177 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { 178 ret = gpiod_direction_input(desc); 179 if (ret) 180 return ret; 181 } 182 183 blocking_notifier_call_chain(&desc->gdev->notifier, 184 GPIO_V2_LINE_CHANGED_CONFIG, 185 desc); 186 } 187 return 0; 188 } 189 190 static long linehandle_ioctl(struct file *file, unsigned int cmd, 191 unsigned long arg) 192 { 193 struct linehandle_state *lh = file->private_data; 194 void __user *ip = (void __user *)arg; 195 struct gpiohandle_data ghd; 196 DECLARE_BITMAP(vals, GPIOHANDLES_MAX); 197 int i; 198 199 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { 200 /* NOTE: It's ok to read values of output lines. */ 201 int ret = gpiod_get_array_value_complex(false, 202 true, 203 lh->num_descs, 204 lh->descs, 205 NULL, 206 vals); 207 if (ret) 208 return ret; 209 210 memset(&ghd, 0, sizeof(ghd)); 211 for (i = 0; i < lh->num_descs; i++) 212 ghd.values[i] = test_bit(i, vals); 213 214 if (copy_to_user(ip, &ghd, sizeof(ghd))) 215 return -EFAULT; 216 217 return 0; 218 } else if (cmd == GPIOHANDLE_SET_LINE_VALUES_IOCTL) { 219 /* 220 * All line descriptors were created at once with the same 221 * flags so just check if the first one is really output. 222 */ 223 if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags)) 224 return -EPERM; 225 226 if (copy_from_user(&ghd, ip, sizeof(ghd))) 227 return -EFAULT; 228 229 /* Clamp all values to [0,1] */ 230 for (i = 0; i < lh->num_descs; i++) 231 __assign_bit(i, vals, ghd.values[i]); 232 233 /* Reuse the array setting function */ 234 return gpiod_set_array_value_complex(false, 235 true, 236 lh->num_descs, 237 lh->descs, 238 NULL, 239 vals); 240 } else if (cmd == GPIOHANDLE_SET_CONFIG_IOCTL) { 241 return linehandle_set_config(lh, ip); 242 } 243 return -EINVAL; 244 } 245 246 #ifdef CONFIG_COMPAT 247 static long linehandle_ioctl_compat(struct file *file, unsigned int cmd, 248 unsigned long arg) 249 { 250 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 251 } 252 #endif 253 254 static void linehandle_free(struct linehandle_state *lh) 255 { 256 int i; 257 258 for (i = 0; i < lh->num_descs; i++) 259 if (lh->descs[i]) 260 gpiod_free(lh->descs[i]); 261 kfree(lh->label); 262 put_device(&lh->gdev->dev); 263 kfree(lh); 264 } 265 266 static int linehandle_release(struct inode *inode, struct file *file) 267 { 268 linehandle_free(file->private_data); 269 return 0; 270 } 271 272 static const struct file_operations linehandle_fileops = { 273 .release = linehandle_release, 274 .owner = THIS_MODULE, 275 .llseek = noop_llseek, 276 .unlocked_ioctl = linehandle_ioctl, 277 #ifdef CONFIG_COMPAT 278 .compat_ioctl = linehandle_ioctl_compat, 279 #endif 280 }; 281 282 static int linehandle_create(struct gpio_device *gdev, void __user *ip) 283 { 284 struct gpiohandle_request handlereq; 285 struct linehandle_state *lh; 286 struct file *file; 287 int fd, i, ret; 288 u32 lflags; 289 290 if (copy_from_user(&handlereq, ip, sizeof(handlereq))) 291 return -EFAULT; 292 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX)) 293 return -EINVAL; 294 295 lflags = handlereq.flags; 296 297 ret = linehandle_validate_flags(lflags); 298 if (ret) 299 return ret; 300 301 lh = kzalloc(sizeof(*lh), GFP_KERNEL); 302 if (!lh) 303 return -ENOMEM; 304 lh->gdev = gdev; 305 get_device(&gdev->dev); 306 307 /* Make sure this is terminated */ 308 handlereq.consumer_label[sizeof(handlereq.consumer_label)-1] = '\0'; 309 if (strlen(handlereq.consumer_label)) { 310 lh->label = kstrdup(handlereq.consumer_label, 311 GFP_KERNEL); 312 if (!lh->label) { 313 ret = -ENOMEM; 314 goto out_free_lh; 315 } 316 } 317 318 lh->num_descs = handlereq.lines; 319 320 /* Request each GPIO */ 321 for (i = 0; i < handlereq.lines; i++) { 322 u32 offset = handlereq.lineoffsets[i]; 323 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset); 324 325 if (IS_ERR(desc)) { 326 ret = PTR_ERR(desc); 327 goto out_free_lh; 328 } 329 330 ret = gpiod_request(desc, lh->label); 331 if (ret) 332 goto out_free_lh; 333 lh->descs[i] = desc; 334 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags); 335 336 ret = gpiod_set_transitory(desc, false); 337 if (ret < 0) 338 goto out_free_lh; 339 340 /* 341 * Lines have to be requested explicitly for input 342 * or output, else the line will be treated "as is". 343 */ 344 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { 345 int val = !!handlereq.default_values[i]; 346 347 ret = gpiod_direction_output(desc, val); 348 if (ret) 349 goto out_free_lh; 350 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { 351 ret = gpiod_direction_input(desc); 352 if (ret) 353 goto out_free_lh; 354 } 355 356 blocking_notifier_call_chain(&desc->gdev->notifier, 357 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 358 359 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 360 offset); 361 } 362 363 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 364 if (fd < 0) { 365 ret = fd; 366 goto out_free_lh; 367 } 368 369 file = anon_inode_getfile("gpio-linehandle", 370 &linehandle_fileops, 371 lh, 372 O_RDONLY | O_CLOEXEC); 373 if (IS_ERR(file)) { 374 ret = PTR_ERR(file); 375 goto out_put_unused_fd; 376 } 377 378 handlereq.fd = fd; 379 if (copy_to_user(ip, &handlereq, sizeof(handlereq))) { 380 /* 381 * fput() will trigger the release() callback, so do not go onto 382 * the regular error cleanup path here. 383 */ 384 fput(file); 385 put_unused_fd(fd); 386 return -EFAULT; 387 } 388 389 fd_install(fd, file); 390 391 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 392 lh->num_descs); 393 394 return 0; 395 396 out_put_unused_fd: 397 put_unused_fd(fd); 398 out_free_lh: 399 linehandle_free(lh); 400 return ret; 401 } 402 #endif /* CONFIG_GPIO_CDEV_V1 */ 403 404 /** 405 * struct line - contains the state of a requested line 406 * @desc: the GPIO descriptor for this line. 407 */ 408 struct line { 409 struct gpio_desc *desc; 410 }; 411 412 /** 413 * struct linereq - contains the state of a userspace line request 414 * @gdev: the GPIO device the line request pertains to 415 * @label: consumer label used to tag GPIO descriptors 416 * @num_lines: the number of lines in the lines array 417 * @lines: the lines held by this line request, with @num_lines elements. 418 */ 419 struct linereq { 420 struct gpio_device *gdev; 421 const char *label; 422 u32 num_lines; 423 struct line lines[]; 424 }; 425 426 #define GPIO_V2_LINE_BIAS_FLAGS \ 427 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \ 428 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \ 429 GPIO_V2_LINE_FLAG_BIAS_DISABLED) 430 431 #define GPIO_V2_LINE_DIRECTION_FLAGS \ 432 (GPIO_V2_LINE_FLAG_INPUT | \ 433 GPIO_V2_LINE_FLAG_OUTPUT) 434 435 #define GPIO_V2_LINE_DRIVE_FLAGS \ 436 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \ 437 GPIO_V2_LINE_FLAG_OPEN_SOURCE) 438 439 #define GPIO_V2_LINE_VALID_FLAGS \ 440 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ 441 GPIO_V2_LINE_DIRECTION_FLAGS | \ 442 GPIO_V2_LINE_DRIVE_FLAGS | \ 443 GPIO_V2_LINE_BIAS_FLAGS) 444 445 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc, 446 unsigned int line_idx) 447 { 448 unsigned int i; 449 u64 mask = BIT_ULL(line_idx); 450 451 for (i = 0; i < lc->num_attrs; i++) { 452 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) && 453 (lc->attrs[i].mask & mask)) 454 return lc->attrs[i].attr.flags; 455 } 456 return lc->flags; 457 } 458 459 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc, 460 unsigned int line_idx) 461 { 462 unsigned int i; 463 u64 mask = BIT_ULL(line_idx); 464 465 for (i = 0; i < lc->num_attrs; i++) { 466 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) && 467 (lc->attrs[i].mask & mask)) 468 return !!(lc->attrs[i].attr.values & mask); 469 } 470 return 0; 471 } 472 473 static int gpio_v2_line_flags_validate(u64 flags) 474 { 475 /* Return an error if an unknown flag is set */ 476 if (flags & ~GPIO_V2_LINE_VALID_FLAGS) 477 return -EINVAL; 478 479 /* 480 * Do not allow both INPUT and OUTPUT flags to be set as they are 481 * contradictory. 482 */ 483 if ((flags & GPIO_V2_LINE_FLAG_INPUT) && 484 (flags & GPIO_V2_LINE_FLAG_OUTPUT)) 485 return -EINVAL; 486 487 /* 488 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single 489 * request. If the hardware actually supports enabling both at the 490 * same time the electrical result would be disastrous. 491 */ 492 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) && 493 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE)) 494 return -EINVAL; 495 496 /* Drive requires explicit output direction. */ 497 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) && 498 !(flags & GPIO_V2_LINE_FLAG_OUTPUT)) 499 return -EINVAL; 500 501 /* Bias requires explicit direction. */ 502 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) && 503 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS)) 504 return -EINVAL; 505 506 /* Only one bias flag can be set. */ 507 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) && 508 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | 509 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) || 510 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) && 511 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) 512 return -EINVAL; 513 514 return 0; 515 } 516 517 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc, 518 unsigned int num_lines) 519 { 520 unsigned int i; 521 u64 flags; 522 int ret; 523 524 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX) 525 return -EINVAL; 526 527 if (memchr_inv(lc->padding, 0, sizeof(lc->padding))) 528 return -EINVAL; 529 530 for (i = 0; i < num_lines; i++) { 531 flags = gpio_v2_line_config_flags(lc, i); 532 ret = gpio_v2_line_flags_validate(flags); 533 if (ret) 534 return ret; 535 } 536 return 0; 537 } 538 539 static void gpio_v2_line_config_flags_to_desc_flags(u64 flags, 540 unsigned long *flagsp) 541 { 542 assign_bit(FLAG_ACTIVE_LOW, flagsp, 543 flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW); 544 545 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) 546 set_bit(FLAG_IS_OUT, flagsp); 547 else if (flags & GPIO_V2_LINE_FLAG_INPUT) 548 clear_bit(FLAG_IS_OUT, flagsp); 549 550 assign_bit(FLAG_OPEN_DRAIN, flagsp, 551 flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN); 552 assign_bit(FLAG_OPEN_SOURCE, flagsp, 553 flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE); 554 555 assign_bit(FLAG_PULL_UP, flagsp, 556 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP); 557 assign_bit(FLAG_PULL_DOWN, flagsp, 558 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN); 559 assign_bit(FLAG_BIAS_DISABLE, flagsp, 560 flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED); 561 } 562 563 static long linereq_get_values(struct linereq *lr, void __user *ip) 564 { 565 struct gpio_v2_line_values lv; 566 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX); 567 struct gpio_desc **descs; 568 unsigned int i, didx, num_get; 569 int ret; 570 571 /* NOTE: It's ok to read values of output lines. */ 572 if (copy_from_user(&lv, ip, sizeof(lv))) 573 return -EFAULT; 574 575 for (num_get = 0, i = 0; i < lr->num_lines; i++) { 576 if (lv.mask & BIT_ULL(i)) { 577 num_get++; 578 descs = &lr->lines[i].desc; 579 } 580 } 581 582 if (num_get == 0) 583 return -EINVAL; 584 585 if (num_get != 1) { 586 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL); 587 if (!descs) 588 return -ENOMEM; 589 for (didx = 0, i = 0; i < lr->num_lines; i++) { 590 if (lv.mask & BIT_ULL(i)) { 591 descs[didx] = lr->lines[i].desc; 592 didx++; 593 } 594 } 595 } 596 ret = gpiod_get_array_value_complex(false, true, num_get, 597 descs, NULL, vals); 598 599 if (num_get != 1) 600 kfree(descs); 601 if (ret) 602 return ret; 603 604 lv.bits = 0; 605 for (didx = 0, i = 0; i < lr->num_lines; i++) { 606 if (lv.mask & BIT_ULL(i)) { 607 if (test_bit(didx, vals)) 608 lv.bits |= BIT_ULL(i); 609 didx++; 610 } 611 } 612 613 if (copy_to_user(ip, &lv, sizeof(lv))) 614 return -EFAULT; 615 616 return 0; 617 } 618 619 static long linereq_ioctl(struct file *file, unsigned int cmd, 620 unsigned long arg) 621 { 622 struct linereq *lr = file->private_data; 623 void __user *ip = (void __user *)arg; 624 625 if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL) 626 return linereq_get_values(lr, ip); 627 628 return -EINVAL; 629 } 630 631 #ifdef CONFIG_COMPAT 632 static long linereq_ioctl_compat(struct file *file, unsigned int cmd, 633 unsigned long arg) 634 { 635 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 636 } 637 #endif 638 639 static void linereq_free(struct linereq *lr) 640 { 641 unsigned int i; 642 643 for (i = 0; i < lr->num_lines; i++) { 644 if (lr->lines[i].desc) 645 gpiod_free(lr->lines[i].desc); 646 } 647 kfree(lr->label); 648 put_device(&lr->gdev->dev); 649 kfree(lr); 650 } 651 652 static int linereq_release(struct inode *inode, struct file *file) 653 { 654 struct linereq *lr = file->private_data; 655 656 linereq_free(lr); 657 return 0; 658 } 659 660 static const struct file_operations line_fileops = { 661 .release = linereq_release, 662 .owner = THIS_MODULE, 663 .llseek = noop_llseek, 664 .unlocked_ioctl = linereq_ioctl, 665 #ifdef CONFIG_COMPAT 666 .compat_ioctl = linereq_ioctl_compat, 667 #endif 668 }; 669 670 static int linereq_create(struct gpio_device *gdev, void __user *ip) 671 { 672 struct gpio_v2_line_request ulr; 673 struct gpio_v2_line_config *lc; 674 struct linereq *lr; 675 struct file *file; 676 u64 flags; 677 unsigned int i; 678 int fd, ret; 679 680 if (copy_from_user(&ulr, ip, sizeof(ulr))) 681 return -EFAULT; 682 683 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX)) 684 return -EINVAL; 685 686 if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding))) 687 return -EINVAL; 688 689 lc = &ulr.config; 690 ret = gpio_v2_line_config_validate(lc, ulr.num_lines); 691 if (ret) 692 return ret; 693 694 lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL); 695 if (!lr) 696 return -ENOMEM; 697 698 lr->gdev = gdev; 699 get_device(&gdev->dev); 700 701 /* Make sure this is terminated */ 702 ulr.consumer[sizeof(ulr.consumer)-1] = '\0'; 703 if (strlen(ulr.consumer)) { 704 /* label is only initialized if consumer is set */ 705 lr->label = kstrdup(ulr.consumer, GFP_KERNEL); 706 if (!lr->label) { 707 ret = -ENOMEM; 708 goto out_free_linereq; 709 } 710 } 711 712 lr->num_lines = ulr.num_lines; 713 714 /* Request each GPIO */ 715 for (i = 0; i < ulr.num_lines; i++) { 716 u32 offset = ulr.offsets[i]; 717 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset); 718 719 if (IS_ERR(desc)) { 720 ret = PTR_ERR(desc); 721 goto out_free_linereq; 722 } 723 724 ret = gpiod_request(desc, lr->label); 725 if (ret) 726 goto out_free_linereq; 727 728 lr->lines[i].desc = desc; 729 flags = gpio_v2_line_config_flags(lc, i); 730 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); 731 732 ret = gpiod_set_transitory(desc, false); 733 if (ret < 0) 734 goto out_free_linereq; 735 736 /* 737 * Lines have to be requested explicitly for input 738 * or output, else the line will be treated "as is". 739 */ 740 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { 741 int val = gpio_v2_line_config_output_value(lc, i); 742 743 ret = gpiod_direction_output(desc, val); 744 if (ret) 745 goto out_free_linereq; 746 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { 747 ret = gpiod_direction_input(desc); 748 if (ret) 749 goto out_free_linereq; 750 } 751 752 blocking_notifier_call_chain(&desc->gdev->notifier, 753 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 754 755 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", 756 offset); 757 } 758 759 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 760 if (fd < 0) { 761 ret = fd; 762 goto out_free_linereq; 763 } 764 765 file = anon_inode_getfile("gpio-line", &line_fileops, lr, 766 O_RDONLY | O_CLOEXEC); 767 if (IS_ERR(file)) { 768 ret = PTR_ERR(file); 769 goto out_put_unused_fd; 770 } 771 772 ulr.fd = fd; 773 if (copy_to_user(ip, &ulr, sizeof(ulr))) { 774 /* 775 * fput() will trigger the release() callback, so do not go onto 776 * the regular error cleanup path here. 777 */ 778 fput(file); 779 put_unused_fd(fd); 780 return -EFAULT; 781 } 782 783 fd_install(fd, file); 784 785 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", 786 lr->num_lines); 787 788 return 0; 789 790 out_put_unused_fd: 791 put_unused_fd(fd); 792 out_free_linereq: 793 linereq_free(lr); 794 return ret; 795 } 796 797 #ifdef CONFIG_GPIO_CDEV_V1 798 799 /* 800 * GPIO line event management 801 */ 802 803 /** 804 * struct lineevent_state - contains the state of a userspace event 805 * @gdev: the GPIO device the event pertains to 806 * @label: consumer label used to tag descriptors 807 * @desc: the GPIO descriptor held by this event 808 * @eflags: the event flags this line was requested with 809 * @irq: the interrupt that trigger in response to events on this GPIO 810 * @wait: wait queue that handles blocking reads of events 811 * @events: KFIFO for the GPIO events 812 * @timestamp: cache for the timestamp storing it between hardirq 813 * and IRQ thread, used to bring the timestamp close to the actual 814 * event 815 */ 816 struct lineevent_state { 817 struct gpio_device *gdev; 818 const char *label; 819 struct gpio_desc *desc; 820 u32 eflags; 821 int irq; 822 wait_queue_head_t wait; 823 DECLARE_KFIFO(events, struct gpioevent_data, 16); 824 u64 timestamp; 825 }; 826 827 #define GPIOEVENT_REQUEST_VALID_FLAGS \ 828 (GPIOEVENT_REQUEST_RISING_EDGE | \ 829 GPIOEVENT_REQUEST_FALLING_EDGE) 830 831 static __poll_t lineevent_poll(struct file *file, 832 struct poll_table_struct *wait) 833 { 834 struct lineevent_state *le = file->private_data; 835 __poll_t events = 0; 836 837 poll_wait(file, &le->wait, wait); 838 839 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock)) 840 events = EPOLLIN | EPOLLRDNORM; 841 842 return events; 843 } 844 845 846 static ssize_t lineevent_read(struct file *file, 847 char __user *buf, 848 size_t count, 849 loff_t *f_ps) 850 { 851 struct lineevent_state *le = file->private_data; 852 struct gpioevent_data ge; 853 ssize_t bytes_read = 0; 854 int ret; 855 856 if (count < sizeof(ge)) 857 return -EINVAL; 858 859 do { 860 spin_lock(&le->wait.lock); 861 if (kfifo_is_empty(&le->events)) { 862 if (bytes_read) { 863 spin_unlock(&le->wait.lock); 864 return bytes_read; 865 } 866 867 if (file->f_flags & O_NONBLOCK) { 868 spin_unlock(&le->wait.lock); 869 return -EAGAIN; 870 } 871 872 ret = wait_event_interruptible_locked(le->wait, 873 !kfifo_is_empty(&le->events)); 874 if (ret) { 875 spin_unlock(&le->wait.lock); 876 return ret; 877 } 878 } 879 880 ret = kfifo_out(&le->events, &ge, 1); 881 spin_unlock(&le->wait.lock); 882 if (ret != 1) { 883 /* 884 * This should never happen - we were holding the lock 885 * from the moment we learned the fifo is no longer 886 * empty until now. 887 */ 888 ret = -EIO; 889 break; 890 } 891 892 if (copy_to_user(buf + bytes_read, &ge, sizeof(ge))) 893 return -EFAULT; 894 bytes_read += sizeof(ge); 895 } while (count >= bytes_read + sizeof(ge)); 896 897 return bytes_read; 898 } 899 900 static void lineevent_free(struct lineevent_state *le) 901 { 902 if (le->irq) 903 free_irq(le->irq, le); 904 if (le->desc) 905 gpiod_free(le->desc); 906 kfree(le->label); 907 put_device(&le->gdev->dev); 908 kfree(le); 909 } 910 911 static int lineevent_release(struct inode *inode, struct file *file) 912 { 913 lineevent_free(file->private_data); 914 return 0; 915 } 916 917 static long lineevent_ioctl(struct file *file, unsigned int cmd, 918 unsigned long arg) 919 { 920 struct lineevent_state *le = file->private_data; 921 void __user *ip = (void __user *)arg; 922 struct gpiohandle_data ghd; 923 924 /* 925 * We can get the value for an event line but not set it, 926 * because it is input by definition. 927 */ 928 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { 929 int val; 930 931 memset(&ghd, 0, sizeof(ghd)); 932 933 val = gpiod_get_value_cansleep(le->desc); 934 if (val < 0) 935 return val; 936 ghd.values[0] = val; 937 938 if (copy_to_user(ip, &ghd, sizeof(ghd))) 939 return -EFAULT; 940 941 return 0; 942 } 943 return -EINVAL; 944 } 945 946 #ifdef CONFIG_COMPAT 947 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd, 948 unsigned long arg) 949 { 950 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 951 } 952 #endif 953 954 static const struct file_operations lineevent_fileops = { 955 .release = lineevent_release, 956 .read = lineevent_read, 957 .poll = lineevent_poll, 958 .owner = THIS_MODULE, 959 .llseek = noop_llseek, 960 .unlocked_ioctl = lineevent_ioctl, 961 #ifdef CONFIG_COMPAT 962 .compat_ioctl = lineevent_ioctl_compat, 963 #endif 964 }; 965 966 static irqreturn_t lineevent_irq_thread(int irq, void *p) 967 { 968 struct lineevent_state *le = p; 969 struct gpioevent_data ge; 970 int ret; 971 972 /* Do not leak kernel stack to userspace */ 973 memset(&ge, 0, sizeof(ge)); 974 975 /* 976 * We may be running from a nested threaded interrupt in which case 977 * we didn't get the timestamp from lineevent_irq_handler(). 978 */ 979 if (!le->timestamp) 980 ge.timestamp = ktime_get_ns(); 981 else 982 ge.timestamp = le->timestamp; 983 984 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE 985 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 986 int level = gpiod_get_value_cansleep(le->desc); 987 988 if (level) 989 /* Emit low-to-high event */ 990 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 991 else 992 /* Emit high-to-low event */ 993 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 994 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) { 995 /* Emit low-to-high event */ 996 ge.id = GPIOEVENT_EVENT_RISING_EDGE; 997 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { 998 /* Emit high-to-low event */ 999 ge.id = GPIOEVENT_EVENT_FALLING_EDGE; 1000 } else { 1001 return IRQ_NONE; 1002 } 1003 1004 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge, 1005 1, &le->wait.lock); 1006 if (ret) 1007 wake_up_poll(&le->wait, EPOLLIN); 1008 else 1009 pr_debug_ratelimited("event FIFO is full - event dropped\n"); 1010 1011 return IRQ_HANDLED; 1012 } 1013 1014 static irqreturn_t lineevent_irq_handler(int irq, void *p) 1015 { 1016 struct lineevent_state *le = p; 1017 1018 /* 1019 * Just store the timestamp in hardirq context so we get it as 1020 * close in time as possible to the actual event. 1021 */ 1022 le->timestamp = ktime_get_ns(); 1023 1024 return IRQ_WAKE_THREAD; 1025 } 1026 1027 static int lineevent_create(struct gpio_device *gdev, void __user *ip) 1028 { 1029 struct gpioevent_request eventreq; 1030 struct lineevent_state *le; 1031 struct gpio_desc *desc; 1032 struct file *file; 1033 u32 offset; 1034 u32 lflags; 1035 u32 eflags; 1036 int fd; 1037 int ret; 1038 int irq, irqflags = 0; 1039 1040 if (copy_from_user(&eventreq, ip, sizeof(eventreq))) 1041 return -EFAULT; 1042 1043 offset = eventreq.lineoffset; 1044 lflags = eventreq.handleflags; 1045 eflags = eventreq.eventflags; 1046 1047 desc = gpiochip_get_desc(gdev->chip, offset); 1048 if (IS_ERR(desc)) 1049 return PTR_ERR(desc); 1050 1051 /* Return an error if a unknown flag is set */ 1052 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) || 1053 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS)) 1054 return -EINVAL; 1055 1056 /* This is just wrong: we don't look for events on output lines */ 1057 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) || 1058 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || 1059 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) 1060 return -EINVAL; 1061 1062 /* Only one bias flag can be set. */ 1063 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && 1064 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | 1065 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || 1066 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && 1067 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) 1068 return -EINVAL; 1069 1070 le = kzalloc(sizeof(*le), GFP_KERNEL); 1071 if (!le) 1072 return -ENOMEM; 1073 le->gdev = gdev; 1074 get_device(&gdev->dev); 1075 1076 /* Make sure this is terminated */ 1077 eventreq.consumer_label[sizeof(eventreq.consumer_label)-1] = '\0'; 1078 if (strlen(eventreq.consumer_label)) { 1079 le->label = kstrdup(eventreq.consumer_label, 1080 GFP_KERNEL); 1081 if (!le->label) { 1082 ret = -ENOMEM; 1083 goto out_free_le; 1084 } 1085 } 1086 1087 ret = gpiod_request(desc, le->label); 1088 if (ret) 1089 goto out_free_le; 1090 le->desc = desc; 1091 le->eflags = eflags; 1092 1093 linehandle_flags_to_desc_flags(lflags, &desc->flags); 1094 1095 ret = gpiod_direction_input(desc); 1096 if (ret) 1097 goto out_free_le; 1098 1099 blocking_notifier_call_chain(&desc->gdev->notifier, 1100 GPIO_V2_LINE_CHANGED_REQUESTED, desc); 1101 1102 irq = gpiod_to_irq(desc); 1103 if (irq <= 0) { 1104 ret = -ENODEV; 1105 goto out_free_le; 1106 } 1107 le->irq = irq; 1108 1109 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE) 1110 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 1111 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 1112 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE) 1113 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 1114 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 1115 irqflags |= IRQF_ONESHOT; 1116 1117 INIT_KFIFO(le->events); 1118 init_waitqueue_head(&le->wait); 1119 1120 /* Request a thread to read the events */ 1121 ret = request_threaded_irq(le->irq, 1122 lineevent_irq_handler, 1123 lineevent_irq_thread, 1124 irqflags, 1125 le->label, 1126 le); 1127 if (ret) 1128 goto out_free_le; 1129 1130 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); 1131 if (fd < 0) { 1132 ret = fd; 1133 goto out_free_le; 1134 } 1135 1136 file = anon_inode_getfile("gpio-event", 1137 &lineevent_fileops, 1138 le, 1139 O_RDONLY | O_CLOEXEC); 1140 if (IS_ERR(file)) { 1141 ret = PTR_ERR(file); 1142 goto out_put_unused_fd; 1143 } 1144 1145 eventreq.fd = fd; 1146 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) { 1147 /* 1148 * fput() will trigger the release() callback, so do not go onto 1149 * the regular error cleanup path here. 1150 */ 1151 fput(file); 1152 put_unused_fd(fd); 1153 return -EFAULT; 1154 } 1155 1156 fd_install(fd, file); 1157 1158 return 0; 1159 1160 out_put_unused_fd: 1161 put_unused_fd(fd); 1162 out_free_le: 1163 lineevent_free(le); 1164 return ret; 1165 } 1166 1167 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2, 1168 struct gpioline_info *info_v1) 1169 { 1170 u64 flagsv2 = info_v2->flags; 1171 1172 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name)); 1173 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer)); 1174 info_v1->line_offset = info_v2->offset; 1175 info_v1->flags = 0; 1176 1177 if (flagsv2 & GPIO_V2_LINE_FLAG_USED) 1178 info_v1->flags |= GPIOLINE_FLAG_KERNEL; 1179 1180 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT) 1181 info_v1->flags |= GPIOLINE_FLAG_IS_OUT; 1182 1183 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW) 1184 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW; 1185 1186 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN) 1187 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN; 1188 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE) 1189 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE; 1190 1191 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP) 1192 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP; 1193 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) 1194 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN; 1195 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED) 1196 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE; 1197 } 1198 1199 static void gpio_v2_line_info_changed_to_v1( 1200 struct gpio_v2_line_info_changed *lic_v2, 1201 struct gpioline_info_changed *lic_v1) 1202 { 1203 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info); 1204 lic_v1->timestamp = lic_v2->timestamp_ns; 1205 lic_v1->event_type = lic_v2->event_type; 1206 } 1207 1208 #endif /* CONFIG_GPIO_CDEV_V1 */ 1209 1210 static void gpio_desc_to_lineinfo(struct gpio_desc *desc, 1211 struct gpio_v2_line_info *info) 1212 { 1213 struct gpio_chip *gc = desc->gdev->chip; 1214 bool ok_for_pinctrl; 1215 unsigned long flags; 1216 1217 memset(info, 0, sizeof(*info)); 1218 info->offset = gpio_chip_hwgpio(desc); 1219 1220 /* 1221 * This function takes a mutex so we must check this before taking 1222 * the spinlock. 1223 * 1224 * FIXME: find a non-racy way to retrieve this information. Maybe a 1225 * lock common to both frameworks? 1226 */ 1227 ok_for_pinctrl = 1228 pinctrl_gpio_can_use_line(gc->base + info->offset); 1229 1230 spin_lock_irqsave(&gpio_lock, flags); 1231 1232 if (desc->name) 1233 strscpy(info->name, desc->name, sizeof(info->name)); 1234 1235 if (desc->label) 1236 strscpy(info->consumer, desc->label, sizeof(info->consumer)); 1237 1238 /* 1239 * Userspace only need to know that the kernel is using this GPIO so 1240 * it can't use it. 1241 */ 1242 info->flags = 0; 1243 if (test_bit(FLAG_REQUESTED, &desc->flags) || 1244 test_bit(FLAG_IS_HOGGED, &desc->flags) || 1245 test_bit(FLAG_USED_AS_IRQ, &desc->flags) || 1246 test_bit(FLAG_EXPORT, &desc->flags) || 1247 test_bit(FLAG_SYSFS, &desc->flags) || 1248 !ok_for_pinctrl) 1249 info->flags |= GPIO_V2_LINE_FLAG_USED; 1250 1251 if (test_bit(FLAG_IS_OUT, &desc->flags)) 1252 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT; 1253 else 1254 info->flags |= GPIO_V2_LINE_FLAG_INPUT; 1255 1256 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) 1257 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW; 1258 1259 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) 1260 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN; 1261 if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) 1262 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE; 1263 1264 if (test_bit(FLAG_BIAS_DISABLE, &desc->flags)) 1265 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED; 1266 if (test_bit(FLAG_PULL_DOWN, &desc->flags)) 1267 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN; 1268 if (test_bit(FLAG_PULL_UP, &desc->flags)) 1269 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP; 1270 1271 spin_unlock_irqrestore(&gpio_lock, flags); 1272 } 1273 1274 struct gpio_chardev_data { 1275 struct gpio_device *gdev; 1276 wait_queue_head_t wait; 1277 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32); 1278 struct notifier_block lineinfo_changed_nb; 1279 unsigned long *watched_lines; 1280 #ifdef CONFIG_GPIO_CDEV_V1 1281 atomic_t watch_abi_version; 1282 #endif 1283 }; 1284 1285 #ifdef CONFIG_GPIO_CDEV_V1 1286 /* 1287 * returns 0 if the versions match, else the previously selected ABI version 1288 */ 1289 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata, 1290 unsigned int version) 1291 { 1292 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version); 1293 1294 if (abiv == version) 1295 return 0; 1296 1297 return abiv; 1298 } 1299 #endif 1300 1301 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, 1302 bool watch) 1303 { 1304 struct gpio_desc *desc; 1305 struct gpio_v2_line_info lineinfo; 1306 1307 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 1308 return -EFAULT; 1309 1310 if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding))) 1311 return -EINVAL; 1312 1313 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset); 1314 if (IS_ERR(desc)) 1315 return PTR_ERR(desc); 1316 1317 if (watch) { 1318 #ifdef CONFIG_GPIO_CDEV_V1 1319 if (lineinfo_ensure_abi_version(cdev, 2)) 1320 return -EPERM; 1321 #endif 1322 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines)) 1323 return -EBUSY; 1324 } 1325 gpio_desc_to_lineinfo(desc, &lineinfo); 1326 1327 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 1328 if (watch) 1329 clear_bit(lineinfo.offset, cdev->watched_lines); 1330 return -EFAULT; 1331 } 1332 1333 return 0; 1334 } 1335 1336 /* 1337 * gpio_ioctl() - ioctl handler for the GPIO chardev 1338 */ 1339 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 1340 { 1341 struct gpio_chardev_data *cdev = file->private_data; 1342 struct gpio_device *gdev = cdev->gdev; 1343 struct gpio_chip *gc = gdev->chip; 1344 void __user *ip = (void __user *)arg; 1345 __u32 offset; 1346 1347 /* We fail any subsequent ioctl():s when the chip is gone */ 1348 if (!gc) 1349 return -ENODEV; 1350 1351 /* Fill in the struct and pass to userspace */ 1352 if (cmd == GPIO_GET_CHIPINFO_IOCTL) { 1353 struct gpiochip_info chipinfo; 1354 1355 memset(&chipinfo, 0, sizeof(chipinfo)); 1356 1357 strscpy(chipinfo.name, dev_name(&gdev->dev), 1358 sizeof(chipinfo.name)); 1359 strscpy(chipinfo.label, gdev->label, 1360 sizeof(chipinfo.label)); 1361 chipinfo.lines = gdev->ngpio; 1362 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo))) 1363 return -EFAULT; 1364 return 0; 1365 #ifdef CONFIG_GPIO_CDEV_V1 1366 } else if (cmd == GPIO_GET_LINEINFO_IOCTL) { 1367 struct gpio_desc *desc; 1368 struct gpioline_info lineinfo; 1369 struct gpio_v2_line_info lineinfo_v2; 1370 1371 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 1372 return -EFAULT; 1373 1374 /* this doubles as a range check on line_offset */ 1375 desc = gpiochip_get_desc(gc, lineinfo.line_offset); 1376 if (IS_ERR(desc)) 1377 return PTR_ERR(desc); 1378 1379 gpio_desc_to_lineinfo(desc, &lineinfo_v2); 1380 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); 1381 1382 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) 1383 return -EFAULT; 1384 return 0; 1385 } else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) { 1386 return linehandle_create(gdev, ip); 1387 } else if (cmd == GPIO_GET_LINEEVENT_IOCTL) { 1388 return lineevent_create(gdev, ip); 1389 } else if (cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) { 1390 struct gpio_desc *desc; 1391 struct gpioline_info lineinfo; 1392 struct gpio_v2_line_info lineinfo_v2; 1393 1394 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) 1395 return -EFAULT; 1396 1397 /* this doubles as a range check on line_offset */ 1398 desc = gpiochip_get_desc(gc, lineinfo.line_offset); 1399 if (IS_ERR(desc)) 1400 return PTR_ERR(desc); 1401 1402 if (lineinfo_ensure_abi_version(cdev, 1)) 1403 return -EPERM; 1404 1405 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines)) 1406 return -EBUSY; 1407 1408 gpio_desc_to_lineinfo(desc, &lineinfo_v2); 1409 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); 1410 1411 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { 1412 clear_bit(lineinfo.line_offset, cdev->watched_lines); 1413 return -EFAULT; 1414 } 1415 1416 return 0; 1417 #endif /* CONFIG_GPIO_CDEV_V1 */ 1418 } else if (cmd == GPIO_V2_GET_LINEINFO_IOCTL || 1419 cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL) { 1420 return lineinfo_get(cdev, ip, 1421 cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL); 1422 } else if (cmd == GPIO_V2_GET_LINE_IOCTL) { 1423 return linereq_create(gdev, ip); 1424 } else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) { 1425 if (copy_from_user(&offset, ip, sizeof(offset))) 1426 return -EFAULT; 1427 1428 if (offset >= cdev->gdev->ngpio) 1429 return -EINVAL; 1430 1431 if (!test_and_clear_bit(offset, cdev->watched_lines)) 1432 return -EBUSY; 1433 1434 return 0; 1435 } 1436 return -EINVAL; 1437 } 1438 1439 #ifdef CONFIG_COMPAT 1440 static long gpio_ioctl_compat(struct file *file, unsigned int cmd, 1441 unsigned long arg) 1442 { 1443 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1444 } 1445 #endif 1446 1447 static struct gpio_chardev_data * 1448 to_gpio_chardev_data(struct notifier_block *nb) 1449 { 1450 return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb); 1451 } 1452 1453 static int lineinfo_changed_notify(struct notifier_block *nb, 1454 unsigned long action, void *data) 1455 { 1456 struct gpio_chardev_data *cdev = to_gpio_chardev_data(nb); 1457 struct gpio_v2_line_info_changed chg; 1458 struct gpio_desc *desc = data; 1459 int ret; 1460 1461 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines)) 1462 return NOTIFY_DONE; 1463 1464 memset(&chg, 0, sizeof(chg)); 1465 chg.event_type = action; 1466 chg.timestamp_ns = ktime_get_ns(); 1467 gpio_desc_to_lineinfo(desc, &chg.info); 1468 1469 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock); 1470 if (ret) 1471 wake_up_poll(&cdev->wait, EPOLLIN); 1472 else 1473 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n"); 1474 1475 return NOTIFY_OK; 1476 } 1477 1478 static __poll_t lineinfo_watch_poll(struct file *file, 1479 struct poll_table_struct *pollt) 1480 { 1481 struct gpio_chardev_data *cdev = file->private_data; 1482 __poll_t events = 0; 1483 1484 poll_wait(file, &cdev->wait, pollt); 1485 1486 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events, 1487 &cdev->wait.lock)) 1488 events = EPOLLIN | EPOLLRDNORM; 1489 1490 return events; 1491 } 1492 1493 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, 1494 size_t count, loff_t *off) 1495 { 1496 struct gpio_chardev_data *cdev = file->private_data; 1497 struct gpio_v2_line_info_changed event; 1498 ssize_t bytes_read = 0; 1499 int ret; 1500 size_t event_size; 1501 1502 #ifndef CONFIG_GPIO_CDEV_V1 1503 event_size = sizeof(struct gpio_v2_line_info_changed); 1504 if (count < event_size) 1505 return -EINVAL; 1506 #endif 1507 1508 do { 1509 spin_lock(&cdev->wait.lock); 1510 if (kfifo_is_empty(&cdev->events)) { 1511 if (bytes_read) { 1512 spin_unlock(&cdev->wait.lock); 1513 return bytes_read; 1514 } 1515 1516 if (file->f_flags & O_NONBLOCK) { 1517 spin_unlock(&cdev->wait.lock); 1518 return -EAGAIN; 1519 } 1520 1521 ret = wait_event_interruptible_locked(cdev->wait, 1522 !kfifo_is_empty(&cdev->events)); 1523 if (ret) { 1524 spin_unlock(&cdev->wait.lock); 1525 return ret; 1526 } 1527 } 1528 #ifdef CONFIG_GPIO_CDEV_V1 1529 /* must be after kfifo check so watch_abi_version is set */ 1530 if (atomic_read(&cdev->watch_abi_version) == 2) 1531 event_size = sizeof(struct gpio_v2_line_info_changed); 1532 else 1533 event_size = sizeof(struct gpioline_info_changed); 1534 if (count < event_size) { 1535 spin_unlock(&cdev->wait.lock); 1536 return -EINVAL; 1537 } 1538 #endif 1539 ret = kfifo_out(&cdev->events, &event, 1); 1540 spin_unlock(&cdev->wait.lock); 1541 if (ret != 1) { 1542 ret = -EIO; 1543 break; 1544 /* We should never get here. See lineevent_read(). */ 1545 } 1546 1547 #ifdef CONFIG_GPIO_CDEV_V1 1548 if (event_size == sizeof(struct gpio_v2_line_info_changed)) { 1549 if (copy_to_user(buf + bytes_read, &event, event_size)) 1550 return -EFAULT; 1551 } else { 1552 struct gpioline_info_changed event_v1; 1553 1554 gpio_v2_line_info_changed_to_v1(&event, &event_v1); 1555 if (copy_to_user(buf + bytes_read, &event_v1, 1556 event_size)) 1557 return -EFAULT; 1558 } 1559 #else 1560 if (copy_to_user(buf + bytes_read, &event, event_size)) 1561 return -EFAULT; 1562 #endif 1563 bytes_read += event_size; 1564 } while (count >= bytes_read + sizeof(event)); 1565 1566 return bytes_read; 1567 } 1568 1569 /** 1570 * gpio_chrdev_open() - open the chardev for ioctl operations 1571 * @inode: inode for this chardev 1572 * @file: file struct for storing private data 1573 * Returns 0 on success 1574 */ 1575 static int gpio_chrdev_open(struct inode *inode, struct file *file) 1576 { 1577 struct gpio_device *gdev = container_of(inode->i_cdev, 1578 struct gpio_device, chrdev); 1579 struct gpio_chardev_data *cdev; 1580 int ret = -ENOMEM; 1581 1582 /* Fail on open if the backing gpiochip is gone */ 1583 if (!gdev->chip) 1584 return -ENODEV; 1585 1586 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL); 1587 if (!cdev) 1588 return -ENOMEM; 1589 1590 cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL); 1591 if (!cdev->watched_lines) 1592 goto out_free_cdev; 1593 1594 init_waitqueue_head(&cdev->wait); 1595 INIT_KFIFO(cdev->events); 1596 cdev->gdev = gdev; 1597 1598 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify; 1599 ret = blocking_notifier_chain_register(&gdev->notifier, 1600 &cdev->lineinfo_changed_nb); 1601 if (ret) 1602 goto out_free_bitmap; 1603 1604 get_device(&gdev->dev); 1605 file->private_data = cdev; 1606 1607 ret = nonseekable_open(inode, file); 1608 if (ret) 1609 goto out_unregister_notifier; 1610 1611 return ret; 1612 1613 out_unregister_notifier: 1614 blocking_notifier_chain_unregister(&gdev->notifier, 1615 &cdev->lineinfo_changed_nb); 1616 out_free_bitmap: 1617 bitmap_free(cdev->watched_lines); 1618 out_free_cdev: 1619 kfree(cdev); 1620 return ret; 1621 } 1622 1623 /** 1624 * gpio_chrdev_release() - close chardev after ioctl operations 1625 * @inode: inode for this chardev 1626 * @file: file struct for storing private data 1627 * Returns 0 on success 1628 */ 1629 static int gpio_chrdev_release(struct inode *inode, struct file *file) 1630 { 1631 struct gpio_chardev_data *cdev = file->private_data; 1632 struct gpio_device *gdev = cdev->gdev; 1633 1634 bitmap_free(cdev->watched_lines); 1635 blocking_notifier_chain_unregister(&gdev->notifier, 1636 &cdev->lineinfo_changed_nb); 1637 put_device(&gdev->dev); 1638 kfree(cdev); 1639 1640 return 0; 1641 } 1642 1643 static const struct file_operations gpio_fileops = { 1644 .release = gpio_chrdev_release, 1645 .open = gpio_chrdev_open, 1646 .poll = lineinfo_watch_poll, 1647 .read = lineinfo_watch_read, 1648 .owner = THIS_MODULE, 1649 .llseek = no_llseek, 1650 .unlocked_ioctl = gpio_ioctl, 1651 #ifdef CONFIG_COMPAT 1652 .compat_ioctl = gpio_ioctl_compat, 1653 #endif 1654 }; 1655 1656 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt) 1657 { 1658 int ret; 1659 1660 cdev_init(&gdev->chrdev, &gpio_fileops); 1661 gdev->chrdev.owner = THIS_MODULE; 1662 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id); 1663 1664 ret = cdev_device_add(&gdev->chrdev, &gdev->dev); 1665 if (ret) 1666 return ret; 1667 1668 chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n", 1669 MAJOR(devt), gdev->id); 1670 1671 return 0; 1672 } 1673 1674 void gpiolib_cdev_unregister(struct gpio_device *gdev) 1675 { 1676 cdev_device_del(&gdev->chrdev, &gdev->dev); 1677 } 1678