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1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/anon_inodes.h>
4#include <linux/bitmap.h>
5#include <linux/cdev.h>
6#include <linux/compat.h>
7#include <linux/device.h>
8#include <linux/err.h>
9#include <linux/file.h>
10#include <linux/gpio.h>
11#include <linux/gpio/driver.h>
12#include <linux/interrupt.h>
13#include <linux/irqreturn.h>
14#include <linux/kernel.h>
15#include <linux/kfifo.h>
16#include <linux/module.h>
17#include <linux/pinctrl/consumer.h>
18#include <linux/poll.h>
19#include <linux/spinlock.h>
20#include <linux/timekeeping.h>
21#include <linux/uaccess.h>
22#include <uapi/linux/gpio.h>
23
24#include "gpiolib.h"
25#include "gpiolib-cdev.h"
26
27/* Character device interface to GPIO.
28 *
29 * The GPIO character device, /dev/gpiochipN, provides userspace an
30 * interface to gpiolib GPIOs via ioctl()s.
31 */
32
33/*
34 * GPIO line handle management
35 */
36
37/**
38 * struct linehandle_state - contains the state of a userspace handle
39 * @gdev: the GPIO device the handle pertains to
40 * @label: consumer label used to tag descriptors
41 * @descs: the GPIO descriptors held by this handle
42 * @num_descs: the number of descriptors held in the descs array
43 */
44struct linehandle_state {
45 struct gpio_device *gdev;
46 const char *label;
47 struct gpio_desc *descs[GPIOHANDLES_MAX];
48 u32 num_descs;
49};
50
51#define GPIOHANDLE_REQUEST_VALID_FLAGS \
52 (GPIOHANDLE_REQUEST_INPUT | \
53 GPIOHANDLE_REQUEST_OUTPUT | \
54 GPIOHANDLE_REQUEST_ACTIVE_LOW | \
55 GPIOHANDLE_REQUEST_BIAS_PULL_UP | \
56 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \
57 GPIOHANDLE_REQUEST_BIAS_DISABLE | \
58 GPIOHANDLE_REQUEST_OPEN_DRAIN | \
59 GPIOHANDLE_REQUEST_OPEN_SOURCE)
60
61static int linehandle_validate_flags(u32 flags)
62{
63 /* Return an error if an unknown flag is set */
64 if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
65 return -EINVAL;
66
67 /*
68 * Do not allow both INPUT & OUTPUT flags to be set as they are
69 * contradictory.
70 */
71 if ((flags & GPIOHANDLE_REQUEST_INPUT) &&
72 (flags & GPIOHANDLE_REQUEST_OUTPUT))
73 return -EINVAL;
74
75 /*
76 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
77 * the hardware actually supports enabling both at the same time the
78 * electrical result would be disastrous.
79 */
80 if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
81 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
82 return -EINVAL;
83
84 /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
85 if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) &&
86 ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
87 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
88 return -EINVAL;
89
90 /* Bias flags only allowed for input or output mode. */
91 if (!((flags & GPIOHANDLE_REQUEST_INPUT) ||
92 (flags & GPIOHANDLE_REQUEST_OUTPUT)) &&
93 ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) ||
94 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) ||
95 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
96 return -EINVAL;
97
98 /* Only one bias flag can be set. */
99 if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
100 (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
101 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
102 ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
103 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
104 return -EINVAL;
105
106 return 0;
107}
108
109static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp)
110{
111 assign_bit(FLAG_ACTIVE_LOW, flagsp,
112 lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
113 assign_bit(FLAG_OPEN_DRAIN, flagsp,
114 lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
115 assign_bit(FLAG_OPEN_SOURCE, flagsp,
116 lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
117 assign_bit(FLAG_PULL_UP, flagsp,
118 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
119 assign_bit(FLAG_PULL_DOWN, flagsp,
120 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
121 assign_bit(FLAG_BIAS_DISABLE, flagsp,
122 lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
123}
124
125static long linehandle_set_config(struct linehandle_state *lh,
126 void __user *ip)
127{
128 struct gpiohandle_config gcnf;
129 struct gpio_desc *desc;
130 int i, ret;
131 u32 lflags;
132
133 if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
134 return -EFAULT;
135
136 lflags = gcnf.flags;
137 ret = linehandle_validate_flags(lflags);
138 if (ret)
139 return ret;
140
141 for (i = 0; i < lh->num_descs; i++) {
142 desc = lh->descs[i];
143 linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags);
144
145 /*
146 * Lines have to be requested explicitly for input
147 * or output, else the line will be treated "as is".
148 */
149 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
150 int val = !!gcnf.default_values[i];
151
152 ret = gpiod_direction_output(desc, val);
153 if (ret)
154 return ret;
155 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
156 ret = gpiod_direction_input(desc);
157 if (ret)
158 return ret;
159 }
160
161 blocking_notifier_call_chain(&desc->gdev->notifier,
162 GPIOLINE_CHANGED_CONFIG, desc);
163 }
164 return 0;
165}
166
167static long linehandle_ioctl(struct file *file, unsigned int cmd,
168 unsigned long arg)
169{
170 struct linehandle_state *lh = file->private_data;
171 void __user *ip = (void __user *)arg;
172 struct gpiohandle_data ghd;
173 DECLARE_BITMAP(vals, GPIOHANDLES_MAX);
174 int i;
175
176 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
177 /* NOTE: It's ok to read values of output lines. */
178 int ret = gpiod_get_array_value_complex(false,
179 true,
180 lh->num_descs,
181 lh->descs,
182 NULL,
183 vals);
184 if (ret)
185 return ret;
186
187 memset(&ghd, 0, sizeof(ghd));
188 for (i = 0; i < lh->num_descs; i++)
189 ghd.values[i] = test_bit(i, vals);
190
191 if (copy_to_user(ip, &ghd, sizeof(ghd)))
192 return -EFAULT;
193
194 return 0;
195 } else if (cmd == GPIOHANDLE_SET_LINE_VALUES_IOCTL) {
196 /*
197 * All line descriptors were created at once with the same
198 * flags so just check if the first one is really output.
199 */
200 if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags))
201 return -EPERM;
202
203 if (copy_from_user(&ghd, ip, sizeof(ghd)))
204 return -EFAULT;
205
206 /* Clamp all values to [0,1] */
207 for (i = 0; i < lh->num_descs; i++)
208 __assign_bit(i, vals, ghd.values[i]);
209
210 /* Reuse the array setting function */
211 return gpiod_set_array_value_complex(false,
212 true,
213 lh->num_descs,
214 lh->descs,
215 NULL,
216 vals);
217 } else if (cmd == GPIOHANDLE_SET_CONFIG_IOCTL) {
218 return linehandle_set_config(lh, ip);
219 }
220 return -EINVAL;
221}
222
223#ifdef CONFIG_COMPAT
224static long linehandle_ioctl_compat(struct file *file, unsigned int cmd,
225 unsigned long arg)
226{
227 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
228}
229#endif
230
231static void linehandle_free(struct linehandle_state *lh)
232{
233 int i;
234
235 for (i = 0; i < lh->num_descs; i++)
236 if (lh->descs[i])
237 gpiod_free(lh->descs[i]);
238 kfree(lh->label);
239 put_device(&lh->gdev->dev);
240 kfree(lh);
241}
242
243static int linehandle_release(struct inode *inode, struct file *file)
244{
245 linehandle_free(file->private_data);
246 return 0;
247}
248
249static const struct file_operations linehandle_fileops = {
250 .release = linehandle_release,
251 .owner = THIS_MODULE,
252 .llseek = noop_llseek,
253 .unlocked_ioctl = linehandle_ioctl,
254#ifdef CONFIG_COMPAT
255 .compat_ioctl = linehandle_ioctl_compat,
256#endif
257};
258
259static int linehandle_create(struct gpio_device *gdev, void __user *ip)
260{
261 struct gpiohandle_request handlereq;
262 struct linehandle_state *lh;
263 struct file *file;
264 int fd, i, ret;
265 u32 lflags;
266
267 if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
268 return -EFAULT;
269 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
270 return -EINVAL;
271
272 lflags = handlereq.flags;
273
274 ret = linehandle_validate_flags(lflags);
275 if (ret)
276 return ret;
277
278 lh = kzalloc(sizeof(*lh), GFP_KERNEL);
279 if (!lh)
280 return -ENOMEM;
281 lh->gdev = gdev;
282 get_device(&gdev->dev);
283
284 /* Make sure this is terminated */
285 handlereq.consumer_label[sizeof(handlereq.consumer_label)-1] = '\0';
286 if (strlen(handlereq.consumer_label)) {
287 lh->label = kstrdup(handlereq.consumer_label,
288 GFP_KERNEL);
289 if (!lh->label) {
290 ret = -ENOMEM;
291 goto out_free_lh;
292 }
293 }
294
295 lh->num_descs = handlereq.lines;
296
297 /* Request each GPIO */
298 for (i = 0; i < handlereq.lines; i++) {
299 u32 offset = handlereq.lineoffsets[i];
300 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
301
302 if (IS_ERR(desc)) {
303 ret = PTR_ERR(desc);
304 goto out_free_lh;
305 }
306
307 ret = gpiod_request(desc, lh->label);
308 if (ret)
309 goto out_free_lh;
310 lh->descs[i] = desc;
311 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);
312
313 ret = gpiod_set_transitory(desc, false);
314 if (ret < 0)
315 goto out_free_lh;
316
317 /*
318 * Lines have to be requested explicitly for input
319 * or output, else the line will be treated "as is".
320 */
321 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
322 int val = !!handlereq.default_values[i];
323
324 ret = gpiod_direction_output(desc, val);
325 if (ret)
326 goto out_free_lh;
327 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
328 ret = gpiod_direction_input(desc);
329 if (ret)
330 goto out_free_lh;
331 }
332
333 blocking_notifier_call_chain(&desc->gdev->notifier,
334 GPIOLINE_CHANGED_REQUESTED, desc);
335
336 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
337 offset);
338 }
339
340 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
341 if (fd < 0) {
342 ret = fd;
343 goto out_free_lh;
344 }
345
346 file = anon_inode_getfile("gpio-linehandle",
347 &linehandle_fileops,
348 lh,
349 O_RDONLY | O_CLOEXEC);
350 if (IS_ERR(file)) {
351 ret = PTR_ERR(file);
352 goto out_put_unused_fd;
353 }
354
355 handlereq.fd = fd;
356 if (copy_to_user(ip, &handlereq, sizeof(handlereq))) {
357 /*
358 * fput() will trigger the release() callback, so do not go onto
359 * the regular error cleanup path here.
360 */
361 fput(file);
362 put_unused_fd(fd);
363 return -EFAULT;
364 }
365
366 fd_install(fd, file);
367
368 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
369 lh->num_descs);
370
371 return 0;
372
373out_put_unused_fd:
374 put_unused_fd(fd);
375out_free_lh:
376 linehandle_free(lh);
377 return ret;
378}
379
380/*
381 * GPIO line event management
382 */
383
384/**
385 * struct lineevent_state - contains the state of a userspace event
386 * @gdev: the GPIO device the event pertains to
387 * @label: consumer label used to tag descriptors
388 * @desc: the GPIO descriptor held by this event
389 * @eflags: the event flags this line was requested with
390 * @irq: the interrupt that trigger in response to events on this GPIO
391 * @wait: wait queue that handles blocking reads of events
392 * @events: KFIFO for the GPIO events
393 * @timestamp: cache for the timestamp storing it between hardirq
394 * and IRQ thread, used to bring the timestamp close to the actual
395 * event
396 */
397struct lineevent_state {
398 struct gpio_device *gdev;
399 const char *label;
400 struct gpio_desc *desc;
401 u32 eflags;
402 int irq;
403 wait_queue_head_t wait;
404 DECLARE_KFIFO(events, struct gpioevent_data, 16);
405 u64 timestamp;
406};
407
408#define GPIOEVENT_REQUEST_VALID_FLAGS \
409 (GPIOEVENT_REQUEST_RISING_EDGE | \
410 GPIOEVENT_REQUEST_FALLING_EDGE)
411
412static __poll_t lineevent_poll(struct file *file,
413 struct poll_table_struct *wait)
414{
415 struct lineevent_state *le = file->private_data;
416 __poll_t events = 0;
417
418 poll_wait(file, &le->wait, wait);
419
420 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
421 events = EPOLLIN | EPOLLRDNORM;
422
423 return events;
424}
425
426static ssize_t lineevent_get_size(void)
427{
428#if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
429 /* i386 has no padding after 'id' */
430 if (in_ia32_syscall()) {
431 struct compat_gpioeevent_data {
432 compat_u64 timestamp;
433 u32 id;
434 };
435
436 return sizeof(struct compat_gpioeevent_data);
437 }
438#endif
439 return sizeof(struct gpioevent_data);
440}
441
442static ssize_t lineevent_read(struct file *file,
443 char __user *buf,
444 size_t count,
445 loff_t *f_ps)
446{
447 struct lineevent_state *le = file->private_data;
448 struct gpioevent_data ge;
449 ssize_t bytes_read = 0;
450 ssize_t ge_size;
451 int ret;
452
453 /*
454 * When compatible system call is being used the struct gpioevent_data,
455 * in case of at least ia32, has different size due to the alignment
456 * differences. Because we have first member 64 bits followed by one of
457 * 32 bits there is no gap between them. The only difference is the
458 * padding at the end of the data structure. Hence, we calculate the
459 * actual sizeof() and pass this as an argument to copy_to_user() to
460 * drop unneeded bytes from the output.
461 */
462 ge_size = lineevent_get_size();
463 if (count < ge_size)
464 return -EINVAL;
465
466 do {
467 spin_lock(&le->wait.lock);
468 if (kfifo_is_empty(&le->events)) {
469 if (bytes_read) {
470 spin_unlock(&le->wait.lock);
471 return bytes_read;
472 }
473
474 if (file->f_flags & O_NONBLOCK) {
475 spin_unlock(&le->wait.lock);
476 return -EAGAIN;
477 }
478
479 ret = wait_event_interruptible_locked(le->wait,
480 !kfifo_is_empty(&le->events));
481 if (ret) {
482 spin_unlock(&le->wait.lock);
483 return ret;
484 }
485 }
486
487 ret = kfifo_out(&le->events, &ge, 1);
488 spin_unlock(&le->wait.lock);
489 if (ret != 1) {
490 /*
491 * This should never happen - we were holding the lock
492 * from the moment we learned the fifo is no longer
493 * empty until now.
494 */
495 ret = -EIO;
496 break;
497 }
498
499 if (copy_to_user(buf + bytes_read, &ge, ge_size))
500 return -EFAULT;
501 bytes_read += ge_size;
502 } while (count >= bytes_read + ge_size);
503
504 return bytes_read;
505}
506
507static void lineevent_free(struct lineevent_state *le)
508{
509 if (le->irq)
510 free_irq(le->irq, le);
511 if (le->desc)
512 gpiod_free(le->desc);
513 kfree(le->label);
514 put_device(&le->gdev->dev);
515 kfree(le);
516}
517
518static int lineevent_release(struct inode *inode, struct file *file)
519{
520 lineevent_free(file->private_data);
521 return 0;
522}
523
524static long lineevent_ioctl(struct file *file, unsigned int cmd,
525 unsigned long arg)
526{
527 struct lineevent_state *le = file->private_data;
528 void __user *ip = (void __user *)arg;
529 struct gpiohandle_data ghd;
530
531 /*
532 * We can get the value for an event line but not set it,
533 * because it is input by definition.
534 */
535 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
536 int val;
537
538 memset(&ghd, 0, sizeof(ghd));
539
540 val = gpiod_get_value_cansleep(le->desc);
541 if (val < 0)
542 return val;
543 ghd.values[0] = val;
544
545 if (copy_to_user(ip, &ghd, sizeof(ghd)))
546 return -EFAULT;
547
548 return 0;
549 }
550 return -EINVAL;
551}
552
553#ifdef CONFIG_COMPAT
554static long lineevent_ioctl_compat(struct file *file, unsigned int cmd,
555 unsigned long arg)
556{
557 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
558}
559#endif
560
561static const struct file_operations lineevent_fileops = {
562 .release = lineevent_release,
563 .read = lineevent_read,
564 .poll = lineevent_poll,
565 .owner = THIS_MODULE,
566 .llseek = noop_llseek,
567 .unlocked_ioctl = lineevent_ioctl,
568#ifdef CONFIG_COMPAT
569 .compat_ioctl = lineevent_ioctl_compat,
570#endif
571};
572
573static irqreturn_t lineevent_irq_thread(int irq, void *p)
574{
575 struct lineevent_state *le = p;
576 struct gpioevent_data ge;
577 int ret;
578
579 /* Do not leak kernel stack to userspace */
580 memset(&ge, 0, sizeof(ge));
581
582 /*
583 * We may be running from a nested threaded interrupt in which case
584 * we didn't get the timestamp from lineevent_irq_handler().
585 */
586 if (!le->timestamp)
587 ge.timestamp = ktime_get_ns();
588 else
589 ge.timestamp = le->timestamp;
590
591 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
592 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
593 int level = gpiod_get_value_cansleep(le->desc);
594
595 if (level)
596 /* Emit low-to-high event */
597 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
598 else
599 /* Emit high-to-low event */
600 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
601 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
602 /* Emit low-to-high event */
603 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
604 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
605 /* Emit high-to-low event */
606 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
607 } else {
608 return IRQ_NONE;
609 }
610
611 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
612 1, &le->wait.lock);
613 if (ret)
614 wake_up_poll(&le->wait, EPOLLIN);
615 else
616 pr_debug_ratelimited("event FIFO is full - event dropped\n");
617
618 return IRQ_HANDLED;
619}
620
621static irqreturn_t lineevent_irq_handler(int irq, void *p)
622{
623 struct lineevent_state *le = p;
624
625 /*
626 * Just store the timestamp in hardirq context so we get it as
627 * close in time as possible to the actual event.
628 */
629 le->timestamp = ktime_get_ns();
630
631 return IRQ_WAKE_THREAD;
632}
633
634static int lineevent_create(struct gpio_device *gdev, void __user *ip)
635{
636 struct gpioevent_request eventreq;
637 struct lineevent_state *le;
638 struct gpio_desc *desc;
639 struct file *file;
640 u32 offset;
641 u32 lflags;
642 u32 eflags;
643 int fd;
644 int ret;
645 int irq, irqflags = 0;
646
647 if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
648 return -EFAULT;
649
650 offset = eventreq.lineoffset;
651 lflags = eventreq.handleflags;
652 eflags = eventreq.eventflags;
653
654 desc = gpiochip_get_desc(gdev->chip, offset);
655 if (IS_ERR(desc))
656 return PTR_ERR(desc);
657
658 /* Return an error if a unknown flag is set */
659 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
660 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
661 return -EINVAL;
662
663 /* This is just wrong: we don't look for events on output lines */
664 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
665 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
666 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
667 return -EINVAL;
668
669 /* Only one bias flag can be set. */
670 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
671 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
672 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
673 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
674 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
675 return -EINVAL;
676
677 le = kzalloc(sizeof(*le), GFP_KERNEL);
678 if (!le)
679 return -ENOMEM;
680 le->gdev = gdev;
681 get_device(&gdev->dev);
682
683 /* Make sure this is terminated */
684 eventreq.consumer_label[sizeof(eventreq.consumer_label)-1] = '\0';
685 if (strlen(eventreq.consumer_label)) {
686 le->label = kstrdup(eventreq.consumer_label,
687 GFP_KERNEL);
688 if (!le->label) {
689 ret = -ENOMEM;
690 goto out_free_le;
691 }
692 }
693
694 ret = gpiod_request(desc, le->label);
695 if (ret)
696 goto out_free_le;
697 le->desc = desc;
698 le->eflags = eflags;
699
700 linehandle_flags_to_desc_flags(lflags, &desc->flags);
701
702 ret = gpiod_direction_input(desc);
703 if (ret)
704 goto out_free_le;
705
706 blocking_notifier_call_chain(&desc->gdev->notifier,
707 GPIOLINE_CHANGED_REQUESTED, desc);
708
709 irq = gpiod_to_irq(desc);
710 if (irq <= 0) {
711 ret = -ENODEV;
712 goto out_free_le;
713 }
714 le->irq = irq;
715
716 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
717 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
718 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
719 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
720 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
721 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
722 irqflags |= IRQF_ONESHOT;
723
724 INIT_KFIFO(le->events);
725 init_waitqueue_head(&le->wait);
726
727 /* Request a thread to read the events */
728 ret = request_threaded_irq(le->irq,
729 lineevent_irq_handler,
730 lineevent_irq_thread,
731 irqflags,
732 le->label,
733 le);
734 if (ret)
735 goto out_free_le;
736
737 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
738 if (fd < 0) {
739 ret = fd;
740 goto out_free_le;
741 }
742
743 file = anon_inode_getfile("gpio-event",
744 &lineevent_fileops,
745 le,
746 O_RDONLY | O_CLOEXEC);
747 if (IS_ERR(file)) {
748 ret = PTR_ERR(file);
749 goto out_put_unused_fd;
750 }
751
752 eventreq.fd = fd;
753 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) {
754 /*
755 * fput() will trigger the release() callback, so do not go onto
756 * the regular error cleanup path here.
757 */
758 fput(file);
759 put_unused_fd(fd);
760 return -EFAULT;
761 }
762
763 fd_install(fd, file);
764
765 return 0;
766
767out_put_unused_fd:
768 put_unused_fd(fd);
769out_free_le:
770 lineevent_free(le);
771 return ret;
772}
773
774static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
775 struct gpioline_info *info)
776{
777 struct gpio_chip *gc = desc->gdev->chip;
778 bool ok_for_pinctrl;
779 unsigned long flags;
780
781 /*
782 * This function takes a mutex so we must check this before taking
783 * the spinlock.
784 *
785 * FIXME: find a non-racy way to retrieve this information. Maybe a
786 * lock common to both frameworks?
787 */
788 ok_for_pinctrl =
789 pinctrl_gpio_can_use_line(gc->base + info->line_offset);
790
791 spin_lock_irqsave(&gpio_lock, flags);
792
793 if (desc->name) {
794 strncpy(info->name, desc->name, sizeof(info->name));
795 info->name[sizeof(info->name) - 1] = '\0';
796 } else {
797 info->name[0] = '\0';
798 }
799
800 if (desc->label) {
801 strncpy(info->consumer, desc->label, sizeof(info->consumer));
802 info->consumer[sizeof(info->consumer) - 1] = '\0';
803 } else {
804 info->consumer[0] = '\0';
805 }
806
807 /*
808 * Userspace only need to know that the kernel is using this GPIO so
809 * it can't use it.
810 */
811 info->flags = 0;
812 if (test_bit(FLAG_REQUESTED, &desc->flags) ||
813 test_bit(FLAG_IS_HOGGED, &desc->flags) ||
814 test_bit(FLAG_USED_AS_IRQ, &desc->flags) ||
815 test_bit(FLAG_EXPORT, &desc->flags) ||
816 test_bit(FLAG_SYSFS, &desc->flags) ||
817 !ok_for_pinctrl)
818 info->flags |= GPIOLINE_FLAG_KERNEL;
819 if (test_bit(FLAG_IS_OUT, &desc->flags))
820 info->flags |= GPIOLINE_FLAG_IS_OUT;
821 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
822 info->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
823 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
824 info->flags |= (GPIOLINE_FLAG_OPEN_DRAIN |
825 GPIOLINE_FLAG_IS_OUT);
826 if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
827 info->flags |= (GPIOLINE_FLAG_OPEN_SOURCE |
828 GPIOLINE_FLAG_IS_OUT);
829 if (test_bit(FLAG_BIAS_DISABLE, &desc->flags))
830 info->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
831 if (test_bit(FLAG_PULL_DOWN, &desc->flags))
832 info->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
833 if (test_bit(FLAG_PULL_UP, &desc->flags))
834 info->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
835
836 spin_unlock_irqrestore(&gpio_lock, flags);
837}
838
839struct gpio_chardev_data {
840 struct gpio_device *gdev;
841 wait_queue_head_t wait;
842 DECLARE_KFIFO(events, struct gpioline_info_changed, 32);
843 struct notifier_block lineinfo_changed_nb;
844 unsigned long *watched_lines;
845};
846
847/*
848 * gpio_ioctl() - ioctl handler for the GPIO chardev
849 */
850static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
851{
852 struct gpio_chardev_data *cdev = file->private_data;
853 struct gpio_device *gdev = cdev->gdev;
854 struct gpio_chip *gc = gdev->chip;
855 void __user *ip = (void __user *)arg;
856 struct gpio_desc *desc;
857 __u32 offset;
858
859 /* We fail any subsequent ioctl():s when the chip is gone */
860 if (!gc)
861 return -ENODEV;
862
863 /* Fill in the struct and pass to userspace */
864 if (cmd == GPIO_GET_CHIPINFO_IOCTL) {
865 struct gpiochip_info chipinfo;
866
867 memset(&chipinfo, 0, sizeof(chipinfo));
868
869 strncpy(chipinfo.name, dev_name(&gdev->dev),
870 sizeof(chipinfo.name));
871 chipinfo.name[sizeof(chipinfo.name)-1] = '\0';
872 strncpy(chipinfo.label, gdev->label,
873 sizeof(chipinfo.label));
874 chipinfo.label[sizeof(chipinfo.label)-1] = '\0';
875 chipinfo.lines = gdev->ngpio;
876 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
877 return -EFAULT;
878 return 0;
879 } else if (cmd == GPIO_GET_LINEINFO_IOCTL) {
880 struct gpioline_info lineinfo;
881
882 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
883 return -EFAULT;
884
885 /* this doubles as a range check on line_offset */
886 desc = gpiochip_get_desc(gc, lineinfo.line_offset);
887 if (IS_ERR(desc))
888 return PTR_ERR(desc);
889
890 gpio_desc_to_lineinfo(desc, &lineinfo);
891
892 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo)))
893 return -EFAULT;
894 return 0;
895 } else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) {
896 return linehandle_create(gdev, ip);
897 } else if (cmd == GPIO_GET_LINEEVENT_IOCTL) {
898 return lineevent_create(gdev, ip);
899 } else if (cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) {
900 struct gpioline_info lineinfo;
901
902 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
903 return -EFAULT;
904
905 /* this doubles as a range check on line_offset */
906 desc = gpiochip_get_desc(gc, lineinfo.line_offset);
907 if (IS_ERR(desc))
908 return PTR_ERR(desc);
909
910 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
911 return -EBUSY;
912
913 gpio_desc_to_lineinfo(desc, &lineinfo);
914
915 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
916 clear_bit(lineinfo.line_offset, cdev->watched_lines);
917 return -EFAULT;
918 }
919
920 return 0;
921 } else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) {
922 if (copy_from_user(&offset, ip, sizeof(offset)))
923 return -EFAULT;
924
925 if (offset >= cdev->gdev->ngpio)
926 return -EINVAL;
927
928 if (!test_and_clear_bit(offset, cdev->watched_lines))
929 return -EBUSY;
930
931 return 0;
932 }
933 return -EINVAL;
934}
935
936#ifdef CONFIG_COMPAT
937static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
938 unsigned long arg)
939{
940 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
941}
942#endif
943
944static struct gpio_chardev_data *
945to_gpio_chardev_data(struct notifier_block *nb)
946{
947 return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
948}
949
950static int lineinfo_changed_notify(struct notifier_block *nb,
951 unsigned long action, void *data)
952{
953 struct gpio_chardev_data *cdev = to_gpio_chardev_data(nb);
954 struct gpioline_info_changed chg;
955 struct gpio_desc *desc = data;
956 int ret;
957
958 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines))
959 return NOTIFY_DONE;
960
961 memset(&chg, 0, sizeof(chg));
962 chg.info.line_offset = gpio_chip_hwgpio(desc);
963 chg.event_type = action;
964 chg.timestamp = ktime_get_ns();
965 gpio_desc_to_lineinfo(desc, &chg.info);
966
967 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
968 if (ret)
969 wake_up_poll(&cdev->wait, EPOLLIN);
970 else
971 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");
972
973 return NOTIFY_OK;
974}
975
976static __poll_t lineinfo_watch_poll(struct file *file,
977 struct poll_table_struct *pollt)
978{
979 struct gpio_chardev_data *cdev = file->private_data;
980 __poll_t events = 0;
981
982 poll_wait(file, &cdev->wait, pollt);
983
984 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events,
985 &cdev->wait.lock))
986 events = EPOLLIN | EPOLLRDNORM;
987
988 return events;
989}
990
991static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
992 size_t count, loff_t *off)
993{
994 struct gpio_chardev_data *cdev = file->private_data;
995 struct gpioline_info_changed event;
996 ssize_t bytes_read = 0;
997 int ret;
998
999 if (count < sizeof(event))
1000 return -EINVAL;
1001
1002 do {
1003 spin_lock(&cdev->wait.lock);
1004 if (kfifo_is_empty(&cdev->events)) {
1005 if (bytes_read) {
1006 spin_unlock(&cdev->wait.lock);
1007 return bytes_read;
1008 }
1009
1010 if (file->f_flags & O_NONBLOCK) {
1011 spin_unlock(&cdev->wait.lock);
1012 return -EAGAIN;
1013 }
1014
1015 ret = wait_event_interruptible_locked(cdev->wait,
1016 !kfifo_is_empty(&cdev->events));
1017 if (ret) {
1018 spin_unlock(&cdev->wait.lock);
1019 return ret;
1020 }
1021 }
1022
1023 ret = kfifo_out(&cdev->events, &event, 1);
1024 spin_unlock(&cdev->wait.lock);
1025 if (ret != 1) {
1026 ret = -EIO;
1027 break;
1028 /* We should never get here. See lineevent_read(). */
1029 }
1030
1031 if (copy_to_user(buf + bytes_read, &event, sizeof(event)))
1032 return -EFAULT;
1033 bytes_read += sizeof(event);
1034 } while (count >= bytes_read + sizeof(event));
1035
1036 return bytes_read;
1037}
1038
1039/**
1040 * gpio_chrdev_open() - open the chardev for ioctl operations
1041 * @inode: inode for this chardev
1042 * @file: file struct for storing private data
1043 * Returns 0 on success
1044 */
1045static int gpio_chrdev_open(struct inode *inode, struct file *file)
1046{
1047 struct gpio_device *gdev = container_of(inode->i_cdev,
1048 struct gpio_device, chrdev);
1049 struct gpio_chardev_data *cdev;
1050 int ret = -ENOMEM;
1051
1052 /* Fail on open if the backing gpiochip is gone */
1053 if (!gdev->chip)
1054 return -ENODEV;
1055
1056 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
1057 if (!cdev)
1058 return -ENOMEM;
1059
1060 cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL);
1061 if (!cdev->watched_lines)
1062 goto out_free_cdev;
1063
1064 init_waitqueue_head(&cdev->wait);
1065 INIT_KFIFO(cdev->events);
1066 cdev->gdev = gdev;
1067
1068 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
1069 ret = blocking_notifier_chain_register(&gdev->notifier,
1070 &cdev->lineinfo_changed_nb);
1071 if (ret)
1072 goto out_free_bitmap;
1073
1074 get_device(&gdev->dev);
1075 file->private_data = cdev;
1076
1077 ret = nonseekable_open(inode, file);
1078 if (ret)
1079 goto out_unregister_notifier;
1080
1081 return ret;
1082
1083out_unregister_notifier:
1084 blocking_notifier_chain_unregister(&gdev->notifier,
1085 &cdev->lineinfo_changed_nb);
1086out_free_bitmap:
1087 bitmap_free(cdev->watched_lines);
1088out_free_cdev:
1089 kfree(cdev);
1090 return ret;
1091}
1092
1093/**
1094 * gpio_chrdev_release() - close chardev after ioctl operations
1095 * @inode: inode for this chardev
1096 * @file: file struct for storing private data
1097 * Returns 0 on success
1098 */
1099static int gpio_chrdev_release(struct inode *inode, struct file *file)
1100{
1101 struct gpio_chardev_data *cdev = file->private_data;
1102 struct gpio_device *gdev = cdev->gdev;
1103
1104 bitmap_free(cdev->watched_lines);
1105 blocking_notifier_chain_unregister(&gdev->notifier,
1106 &cdev->lineinfo_changed_nb);
1107 put_device(&gdev->dev);
1108 kfree(cdev);
1109
1110 return 0;
1111}
1112
1113static const struct file_operations gpio_fileops = {
1114 .release = gpio_chrdev_release,
1115 .open = gpio_chrdev_open,
1116 .poll = lineinfo_watch_poll,
1117 .read = lineinfo_watch_read,
1118 .owner = THIS_MODULE,
1119 .llseek = no_llseek,
1120 .unlocked_ioctl = gpio_ioctl,
1121#ifdef CONFIG_COMPAT
1122 .compat_ioctl = gpio_ioctl_compat,
1123#endif
1124};
1125
1126int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
1127{
1128 int ret;
1129
1130 cdev_init(&gdev->chrdev, &gpio_fileops);
1131 gdev->chrdev.owner = THIS_MODULE;
1132 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
1133
1134 ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
1135 if (ret)
1136 return ret;
1137
1138 chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
1139 MAJOR(devt), gdev->id);
1140
1141 return 0;
1142}
1143
1144void gpiolib_cdev_unregister(struct gpio_device *gdev)
1145{
1146 cdev_device_del(&gdev->chrdev, &gdev->dev);
1147}
1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/anon_inodes.h>
4#include <linux/atomic.h>
5#include <linux/bitmap.h>
6#include <linux/build_bug.h>
7#include <linux/cdev.h>
8#include <linux/compat.h>
9#include <linux/compiler.h>
10#include <linux/device.h>
11#include <linux/err.h>
12#include <linux/file.h>
13#include <linux/gpio.h>
14#include <linux/gpio/driver.h>
15#include <linux/hte.h>
16#include <linux/interrupt.h>
17#include <linux/irqreturn.h>
18#include <linux/kernel.h>
19#include <linux/kfifo.h>
20#include <linux/module.h>
21#include <linux/mutex.h>
22#include <linux/pinctrl/consumer.h>
23#include <linux/poll.h>
24#include <linux/seq_file.h>
25#include <linux/spinlock.h>
26#include <linux/timekeeping.h>
27#include <linux/uaccess.h>
28#include <linux/workqueue.h>
29
30#include <uapi/linux/gpio.h>
31
32#include "gpiolib.h"
33#include "gpiolib-cdev.h"
34
35/*
36 * Array sizes must ensure 64-bit alignment and not create holes in the
37 * struct packing.
38 */
39static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2));
40static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8));
41
42/*
43 * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility
44 */
45static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8));
46static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8));
47static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8));
48static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8));
49static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8));
50static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8));
51static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8));
52static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8));
53
54/* Character device interface to GPIO.
55 *
56 * The GPIO character device, /dev/gpiochipN, provides userspace an
57 * interface to gpiolib GPIOs via ioctl()s.
58 */
59
60typedef __poll_t (*poll_fn)(struct file *, struct poll_table_struct *);
61typedef long (*ioctl_fn)(struct file *, unsigned int, unsigned long);
62typedef ssize_t (*read_fn)(struct file *, char __user *,
63 size_t count, loff_t *);
64
65static __poll_t call_poll_locked(struct file *file,
66 struct poll_table_struct *wait,
67 struct gpio_device *gdev, poll_fn func)
68{
69 __poll_t ret;
70
71 down_read(&gdev->sem);
72 ret = func(file, wait);
73 up_read(&gdev->sem);
74
75 return ret;
76}
77
78static long call_ioctl_locked(struct file *file, unsigned int cmd,
79 unsigned long arg, struct gpio_device *gdev,
80 ioctl_fn func)
81{
82 long ret;
83
84 down_read(&gdev->sem);
85 ret = func(file, cmd, arg);
86 up_read(&gdev->sem);
87
88 return ret;
89}
90
91static ssize_t call_read_locked(struct file *file, char __user *buf,
92 size_t count, loff_t *f_ps,
93 struct gpio_device *gdev, read_fn func)
94{
95 ssize_t ret;
96
97 down_read(&gdev->sem);
98 ret = func(file, buf, count, f_ps);
99 up_read(&gdev->sem);
100
101 return ret;
102}
103
104/*
105 * GPIO line handle management
106 */
107
108#ifdef CONFIG_GPIO_CDEV_V1
109/**
110 * struct linehandle_state - contains the state of a userspace handle
111 * @gdev: the GPIO device the handle pertains to
112 * @label: consumer label used to tag descriptors
113 * @descs: the GPIO descriptors held by this handle
114 * @num_descs: the number of descriptors held in the descs array
115 */
116struct linehandle_state {
117 struct gpio_device *gdev;
118 const char *label;
119 struct gpio_desc *descs[GPIOHANDLES_MAX];
120 u32 num_descs;
121};
122
123#define GPIOHANDLE_REQUEST_VALID_FLAGS \
124 (GPIOHANDLE_REQUEST_INPUT | \
125 GPIOHANDLE_REQUEST_OUTPUT | \
126 GPIOHANDLE_REQUEST_ACTIVE_LOW | \
127 GPIOHANDLE_REQUEST_BIAS_PULL_UP | \
128 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \
129 GPIOHANDLE_REQUEST_BIAS_DISABLE | \
130 GPIOHANDLE_REQUEST_OPEN_DRAIN | \
131 GPIOHANDLE_REQUEST_OPEN_SOURCE)
132
133static int linehandle_validate_flags(u32 flags)
134{
135 /* Return an error if an unknown flag is set */
136 if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
137 return -EINVAL;
138
139 /*
140 * Do not allow both INPUT & OUTPUT flags to be set as they are
141 * contradictory.
142 */
143 if ((flags & GPIOHANDLE_REQUEST_INPUT) &&
144 (flags & GPIOHANDLE_REQUEST_OUTPUT))
145 return -EINVAL;
146
147 /*
148 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
149 * the hardware actually supports enabling both at the same time the
150 * electrical result would be disastrous.
151 */
152 if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
153 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
154 return -EINVAL;
155
156 /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
157 if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) &&
158 ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
159 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
160 return -EINVAL;
161
162 /* Bias flags only allowed for input or output mode. */
163 if (!((flags & GPIOHANDLE_REQUEST_INPUT) ||
164 (flags & GPIOHANDLE_REQUEST_OUTPUT)) &&
165 ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) ||
166 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) ||
167 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
168 return -EINVAL;
169
170 /* Only one bias flag can be set. */
171 if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
172 (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
173 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
174 ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
175 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
176 return -EINVAL;
177
178 return 0;
179}
180
181static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp)
182{
183 assign_bit(FLAG_ACTIVE_LOW, flagsp,
184 lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
185 assign_bit(FLAG_OPEN_DRAIN, flagsp,
186 lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
187 assign_bit(FLAG_OPEN_SOURCE, flagsp,
188 lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
189 assign_bit(FLAG_PULL_UP, flagsp,
190 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
191 assign_bit(FLAG_PULL_DOWN, flagsp,
192 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
193 assign_bit(FLAG_BIAS_DISABLE, flagsp,
194 lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
195}
196
197static long linehandle_set_config(struct linehandle_state *lh,
198 void __user *ip)
199{
200 struct gpiohandle_config gcnf;
201 struct gpio_desc *desc;
202 int i, ret;
203 u32 lflags;
204
205 if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
206 return -EFAULT;
207
208 lflags = gcnf.flags;
209 ret = linehandle_validate_flags(lflags);
210 if (ret)
211 return ret;
212
213 for (i = 0; i < lh->num_descs; i++) {
214 desc = lh->descs[i];
215 linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags);
216
217 /*
218 * Lines have to be requested explicitly for input
219 * or output, else the line will be treated "as is".
220 */
221 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
222 int val = !!gcnf.default_values[i];
223
224 ret = gpiod_direction_output(desc, val);
225 if (ret)
226 return ret;
227 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
228 ret = gpiod_direction_input(desc);
229 if (ret)
230 return ret;
231 }
232
233 blocking_notifier_call_chain(&desc->gdev->notifier,
234 GPIO_V2_LINE_CHANGED_CONFIG,
235 desc);
236 }
237 return 0;
238}
239
240static long linehandle_ioctl_unlocked(struct file *file, unsigned int cmd,
241 unsigned long arg)
242{
243 struct linehandle_state *lh = file->private_data;
244 void __user *ip = (void __user *)arg;
245 struct gpiohandle_data ghd;
246 DECLARE_BITMAP(vals, GPIOHANDLES_MAX);
247 unsigned int i;
248 int ret;
249
250 if (!lh->gdev->chip)
251 return -ENODEV;
252
253 switch (cmd) {
254 case GPIOHANDLE_GET_LINE_VALUES_IOCTL:
255 /* NOTE: It's okay to read values of output lines */
256 ret = gpiod_get_array_value_complex(false, true,
257 lh->num_descs, lh->descs,
258 NULL, vals);
259 if (ret)
260 return ret;
261
262 memset(&ghd, 0, sizeof(ghd));
263 for (i = 0; i < lh->num_descs; i++)
264 ghd.values[i] = test_bit(i, vals);
265
266 if (copy_to_user(ip, &ghd, sizeof(ghd)))
267 return -EFAULT;
268
269 return 0;
270 case GPIOHANDLE_SET_LINE_VALUES_IOCTL:
271 /*
272 * All line descriptors were created at once with the same
273 * flags so just check if the first one is really output.
274 */
275 if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags))
276 return -EPERM;
277
278 if (copy_from_user(&ghd, ip, sizeof(ghd)))
279 return -EFAULT;
280
281 /* Clamp all values to [0,1] */
282 for (i = 0; i < lh->num_descs; i++)
283 __assign_bit(i, vals, ghd.values[i]);
284
285 /* Reuse the array setting function */
286 return gpiod_set_array_value_complex(false,
287 true,
288 lh->num_descs,
289 lh->descs,
290 NULL,
291 vals);
292 case GPIOHANDLE_SET_CONFIG_IOCTL:
293 return linehandle_set_config(lh, ip);
294 default:
295 return -EINVAL;
296 }
297}
298
299static long linehandle_ioctl(struct file *file, unsigned int cmd,
300 unsigned long arg)
301{
302 struct linehandle_state *lh = file->private_data;
303
304 return call_ioctl_locked(file, cmd, arg, lh->gdev,
305 linehandle_ioctl_unlocked);
306}
307
308#ifdef CONFIG_COMPAT
309static long linehandle_ioctl_compat(struct file *file, unsigned int cmd,
310 unsigned long arg)
311{
312 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
313}
314#endif
315
316static void linehandle_free(struct linehandle_state *lh)
317{
318 int i;
319
320 for (i = 0; i < lh->num_descs; i++)
321 if (lh->descs[i])
322 gpiod_free(lh->descs[i]);
323 kfree(lh->label);
324 put_device(&lh->gdev->dev);
325 kfree(lh);
326}
327
328static int linehandle_release(struct inode *inode, struct file *file)
329{
330 linehandle_free(file->private_data);
331 return 0;
332}
333
334static const struct file_operations linehandle_fileops = {
335 .release = linehandle_release,
336 .owner = THIS_MODULE,
337 .llseek = noop_llseek,
338 .unlocked_ioctl = linehandle_ioctl,
339#ifdef CONFIG_COMPAT
340 .compat_ioctl = linehandle_ioctl_compat,
341#endif
342};
343
344static int linehandle_create(struct gpio_device *gdev, void __user *ip)
345{
346 struct gpiohandle_request handlereq;
347 struct linehandle_state *lh;
348 struct file *file;
349 int fd, i, ret;
350 u32 lflags;
351
352 if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
353 return -EFAULT;
354 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
355 return -EINVAL;
356
357 lflags = handlereq.flags;
358
359 ret = linehandle_validate_flags(lflags);
360 if (ret)
361 return ret;
362
363 lh = kzalloc(sizeof(*lh), GFP_KERNEL);
364 if (!lh)
365 return -ENOMEM;
366 lh->gdev = gdev;
367 get_device(&gdev->dev);
368
369 if (handlereq.consumer_label[0] != '\0') {
370 /* label is only initialized if consumer_label is set */
371 lh->label = kstrndup(handlereq.consumer_label,
372 sizeof(handlereq.consumer_label) - 1,
373 GFP_KERNEL);
374 if (!lh->label) {
375 ret = -ENOMEM;
376 goto out_free_lh;
377 }
378 }
379
380 lh->num_descs = handlereq.lines;
381
382 /* Request each GPIO */
383 for (i = 0; i < handlereq.lines; i++) {
384 u32 offset = handlereq.lineoffsets[i];
385 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
386
387 if (IS_ERR(desc)) {
388 ret = PTR_ERR(desc);
389 goto out_free_lh;
390 }
391
392 ret = gpiod_request_user(desc, lh->label);
393 if (ret)
394 goto out_free_lh;
395 lh->descs[i] = desc;
396 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);
397
398 ret = gpiod_set_transitory(desc, false);
399 if (ret < 0)
400 goto out_free_lh;
401
402 /*
403 * Lines have to be requested explicitly for input
404 * or output, else the line will be treated "as is".
405 */
406 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
407 int val = !!handlereq.default_values[i];
408
409 ret = gpiod_direction_output(desc, val);
410 if (ret)
411 goto out_free_lh;
412 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
413 ret = gpiod_direction_input(desc);
414 if (ret)
415 goto out_free_lh;
416 }
417
418 blocking_notifier_call_chain(&desc->gdev->notifier,
419 GPIO_V2_LINE_CHANGED_REQUESTED, desc);
420
421 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
422 offset);
423 }
424
425 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
426 if (fd < 0) {
427 ret = fd;
428 goto out_free_lh;
429 }
430
431 file = anon_inode_getfile("gpio-linehandle",
432 &linehandle_fileops,
433 lh,
434 O_RDONLY | O_CLOEXEC);
435 if (IS_ERR(file)) {
436 ret = PTR_ERR(file);
437 goto out_put_unused_fd;
438 }
439
440 handlereq.fd = fd;
441 if (copy_to_user(ip, &handlereq, sizeof(handlereq))) {
442 /*
443 * fput() will trigger the release() callback, so do not go onto
444 * the regular error cleanup path here.
445 */
446 fput(file);
447 put_unused_fd(fd);
448 return -EFAULT;
449 }
450
451 fd_install(fd, file);
452
453 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
454 lh->num_descs);
455
456 return 0;
457
458out_put_unused_fd:
459 put_unused_fd(fd);
460out_free_lh:
461 linehandle_free(lh);
462 return ret;
463}
464#endif /* CONFIG_GPIO_CDEV_V1 */
465
466/**
467 * struct line - contains the state of a requested line
468 * @desc: the GPIO descriptor for this line.
469 * @req: the corresponding line request
470 * @irq: the interrupt triggered in response to events on this GPIO
471 * @edflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or
472 * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied
473 * @timestamp_ns: cache for the timestamp storing it between hardirq and
474 * IRQ thread, used to bring the timestamp close to the actual event
475 * @req_seqno: the seqno for the current edge event in the sequence of
476 * events for the corresponding line request. This is drawn from the @req.
477 * @line_seqno: the seqno for the current edge event in the sequence of
478 * events for this line.
479 * @work: the worker that implements software debouncing
480 * @sw_debounced: flag indicating if the software debouncer is active
481 * @level: the current debounced physical level of the line
482 * @hdesc: the Hardware Timestamp Engine (HTE) descriptor
483 * @raw_level: the line level at the time of event
484 * @total_discard_seq: the running counter of the discarded events
485 * @last_seqno: the last sequence number before debounce period expires
486 */
487struct line {
488 struct gpio_desc *desc;
489 /*
490 * -- edge detector specific fields --
491 */
492 struct linereq *req;
493 unsigned int irq;
494 /*
495 * The flags for the active edge detector configuration.
496 *
497 * edflags is set by linereq_create(), linereq_free(), and
498 * linereq_set_config_unlocked(), which are themselves mutually
499 * exclusive, and is accessed by edge_irq_thread(),
500 * process_hw_ts_thread() and debounce_work_func(),
501 * which can all live with a slightly stale value.
502 */
503 u64 edflags;
504 /*
505 * timestamp_ns and req_seqno are accessed only by
506 * edge_irq_handler() and edge_irq_thread(), which are themselves
507 * mutually exclusive, so no additional protection is necessary.
508 */
509 u64 timestamp_ns;
510 u32 req_seqno;
511 /*
512 * line_seqno is accessed by either edge_irq_thread() or
513 * debounce_work_func(), which are themselves mutually exclusive,
514 * so no additional protection is necessary.
515 */
516 u32 line_seqno;
517 /*
518 * -- debouncer specific fields --
519 */
520 struct delayed_work work;
521 /*
522 * sw_debounce is accessed by linereq_set_config(), which is the
523 * only setter, and linereq_get_values(), which can live with a
524 * slightly stale value.
525 */
526 unsigned int sw_debounced;
527 /*
528 * level is accessed by debounce_work_func(), which is the only
529 * setter, and linereq_get_values() which can live with a slightly
530 * stale value.
531 */
532 unsigned int level;
533#ifdef CONFIG_HTE
534 struct hte_ts_desc hdesc;
535 /*
536 * HTE provider sets line level at the time of event. The valid
537 * value is 0 or 1 and negative value for an error.
538 */
539 int raw_level;
540 /*
541 * when sw_debounce is set on HTE enabled line, this is running
542 * counter of the discarded events.
543 */
544 u32 total_discard_seq;
545 /*
546 * when sw_debounce is set on HTE enabled line, this variable records
547 * last sequence number before debounce period expires.
548 */
549 u32 last_seqno;
550#endif /* CONFIG_HTE */
551};
552
553/**
554 * struct linereq - contains the state of a userspace line request
555 * @gdev: the GPIO device the line request pertains to
556 * @label: consumer label used to tag GPIO descriptors
557 * @num_lines: the number of lines in the lines array
558 * @wait: wait queue that handles blocking reads of events
559 * @event_buffer_size: the number of elements allocated in @events
560 * @events: KFIFO for the GPIO events
561 * @seqno: the sequence number for edge events generated on all lines in
562 * this line request. Note that this is not used when @num_lines is 1, as
563 * the line_seqno is then the same and is cheaper to calculate.
564 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency
565 * of configuration, particularly multi-step accesses to desc flags.
566 * @lines: the lines held by this line request, with @num_lines elements.
567 */
568struct linereq {
569 struct gpio_device *gdev;
570 const char *label;
571 u32 num_lines;
572 wait_queue_head_t wait;
573 u32 event_buffer_size;
574 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
575 atomic_t seqno;
576 struct mutex config_mutex;
577 struct line lines[];
578};
579
580#define GPIO_V2_LINE_BIAS_FLAGS \
581 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \
582 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \
583 GPIO_V2_LINE_FLAG_BIAS_DISABLED)
584
585#define GPIO_V2_LINE_DIRECTION_FLAGS \
586 (GPIO_V2_LINE_FLAG_INPUT | \
587 GPIO_V2_LINE_FLAG_OUTPUT)
588
589#define GPIO_V2_LINE_DRIVE_FLAGS \
590 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \
591 GPIO_V2_LINE_FLAG_OPEN_SOURCE)
592
593#define GPIO_V2_LINE_EDGE_FLAGS \
594 (GPIO_V2_LINE_FLAG_EDGE_RISING | \
595 GPIO_V2_LINE_FLAG_EDGE_FALLING)
596
597#define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS
598
599#define GPIO_V2_LINE_VALID_FLAGS \
600 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
601 GPIO_V2_LINE_DIRECTION_FLAGS | \
602 GPIO_V2_LINE_DRIVE_FLAGS | \
603 GPIO_V2_LINE_EDGE_FLAGS | \
604 GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \
605 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
606 GPIO_V2_LINE_BIAS_FLAGS)
607
608/* subset of flags relevant for edge detector configuration */
609#define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \
610 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
611 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
612 GPIO_V2_LINE_EDGE_FLAGS)
613
614static void linereq_put_event(struct linereq *lr,
615 struct gpio_v2_line_event *le)
616{
617 bool overflow = false;
618
619 spin_lock(&lr->wait.lock);
620 if (kfifo_is_full(&lr->events)) {
621 overflow = true;
622 kfifo_skip(&lr->events);
623 }
624 kfifo_in(&lr->events, le, 1);
625 spin_unlock(&lr->wait.lock);
626 if (!overflow)
627 wake_up_poll(&lr->wait, EPOLLIN);
628 else
629 pr_debug_ratelimited("event FIFO is full - event dropped\n");
630}
631
632static u64 line_event_timestamp(struct line *line)
633{
634 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags))
635 return ktime_get_real_ns();
636 else if (IS_ENABLED(CONFIG_HTE) &&
637 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))
638 return line->timestamp_ns;
639
640 return ktime_get_ns();
641}
642
643static u32 line_event_id(int level)
644{
645 return level ? GPIO_V2_LINE_EVENT_RISING_EDGE :
646 GPIO_V2_LINE_EVENT_FALLING_EDGE;
647}
648
649#ifdef CONFIG_HTE
650
651static enum hte_return process_hw_ts_thread(void *p)
652{
653 struct line *line;
654 struct linereq *lr;
655 struct gpio_v2_line_event le;
656 u64 edflags;
657 int level;
658
659 if (!p)
660 return HTE_CB_HANDLED;
661
662 line = p;
663 lr = line->req;
664
665 memset(&le, 0, sizeof(le));
666
667 le.timestamp_ns = line->timestamp_ns;
668 edflags = READ_ONCE(line->edflags);
669
670 switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) {
671 case GPIO_V2_LINE_FLAG_EDGE_BOTH:
672 level = (line->raw_level >= 0) ?
673 line->raw_level :
674 gpiod_get_raw_value_cansleep(line->desc);
675
676 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
677 level = !level;
678
679 le.id = line_event_id(level);
680 break;
681 case GPIO_V2_LINE_FLAG_EDGE_RISING:
682 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
683 break;
684 case GPIO_V2_LINE_FLAG_EDGE_FALLING:
685 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
686 break;
687 default:
688 return HTE_CB_HANDLED;
689 }
690 le.line_seqno = line->line_seqno;
691 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
692 le.offset = gpio_chip_hwgpio(line->desc);
693
694 linereq_put_event(lr, &le);
695
696 return HTE_CB_HANDLED;
697}
698
699static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p)
700{
701 struct line *line;
702 struct linereq *lr;
703 int diff_seqno = 0;
704
705 if (!ts || !p)
706 return HTE_CB_HANDLED;
707
708 line = p;
709 line->timestamp_ns = ts->tsc;
710 line->raw_level = ts->raw_level;
711 lr = line->req;
712
713 if (READ_ONCE(line->sw_debounced)) {
714 line->total_discard_seq++;
715 line->last_seqno = ts->seq;
716 mod_delayed_work(system_wq, &line->work,
717 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
718 } else {
719 if (unlikely(ts->seq < line->line_seqno))
720 return HTE_CB_HANDLED;
721
722 diff_seqno = ts->seq - line->line_seqno;
723 line->line_seqno = ts->seq;
724 if (lr->num_lines != 1)
725 line->req_seqno = atomic_add_return(diff_seqno,
726 &lr->seqno);
727
728 return HTE_RUN_SECOND_CB;
729 }
730
731 return HTE_CB_HANDLED;
732}
733
734static int hte_edge_setup(struct line *line, u64 eflags)
735{
736 int ret;
737 unsigned long flags = 0;
738 struct hte_ts_desc *hdesc = &line->hdesc;
739
740 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
741 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
742 HTE_FALLING_EDGE_TS :
743 HTE_RISING_EDGE_TS;
744 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
745 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
746 HTE_RISING_EDGE_TS :
747 HTE_FALLING_EDGE_TS;
748
749 line->total_discard_seq = 0;
750
751 hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL,
752 line->desc);
753
754 ret = hte_ts_get(NULL, hdesc, 0);
755 if (ret)
756 return ret;
757
758 return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread,
759 line);
760}
761
762#else
763
764static int hte_edge_setup(struct line *line, u64 eflags)
765{
766 return 0;
767}
768#endif /* CONFIG_HTE */
769
770static irqreturn_t edge_irq_thread(int irq, void *p)
771{
772 struct line *line = p;
773 struct linereq *lr = line->req;
774 struct gpio_v2_line_event le;
775
776 /* Do not leak kernel stack to userspace */
777 memset(&le, 0, sizeof(le));
778
779 if (line->timestamp_ns) {
780 le.timestamp_ns = line->timestamp_ns;
781 } else {
782 /*
783 * We may be running from a nested threaded interrupt in
784 * which case we didn't get the timestamp from
785 * edge_irq_handler().
786 */
787 le.timestamp_ns = line_event_timestamp(line);
788 if (lr->num_lines != 1)
789 line->req_seqno = atomic_inc_return(&lr->seqno);
790 }
791 line->timestamp_ns = 0;
792
793 switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) {
794 case GPIO_V2_LINE_FLAG_EDGE_BOTH:
795 le.id = line_event_id(gpiod_get_value_cansleep(line->desc));
796 break;
797 case GPIO_V2_LINE_FLAG_EDGE_RISING:
798 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
799 break;
800 case GPIO_V2_LINE_FLAG_EDGE_FALLING:
801 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
802 break;
803 default:
804 return IRQ_NONE;
805 }
806 line->line_seqno++;
807 le.line_seqno = line->line_seqno;
808 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
809 le.offset = gpio_chip_hwgpio(line->desc);
810
811 linereq_put_event(lr, &le);
812
813 return IRQ_HANDLED;
814}
815
816static irqreturn_t edge_irq_handler(int irq, void *p)
817{
818 struct line *line = p;
819 struct linereq *lr = line->req;
820
821 /*
822 * Just store the timestamp in hardirq context so we get it as
823 * close in time as possible to the actual event.
824 */
825 line->timestamp_ns = line_event_timestamp(line);
826
827 if (lr->num_lines != 1)
828 line->req_seqno = atomic_inc_return(&lr->seqno);
829
830 return IRQ_WAKE_THREAD;
831}
832
833/*
834 * returns the current debounced logical value.
835 */
836static bool debounced_value(struct line *line)
837{
838 bool value;
839
840 /*
841 * minor race - debouncer may be stopped here, so edge_detector_stop()
842 * must leave the value unchanged so the following will read the level
843 * from when the debouncer was last running.
844 */
845 value = READ_ONCE(line->level);
846
847 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
848 value = !value;
849
850 return value;
851}
852
853static irqreturn_t debounce_irq_handler(int irq, void *p)
854{
855 struct line *line = p;
856
857 mod_delayed_work(system_wq, &line->work,
858 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
859
860 return IRQ_HANDLED;
861}
862
863static void debounce_work_func(struct work_struct *work)
864{
865 struct gpio_v2_line_event le;
866 struct line *line = container_of(work, struct line, work.work);
867 struct linereq *lr;
868 u64 eflags, edflags = READ_ONCE(line->edflags);
869 int level = -1;
870#ifdef CONFIG_HTE
871 int diff_seqno;
872
873 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
874 level = line->raw_level;
875#endif
876 if (level < 0)
877 level = gpiod_get_raw_value_cansleep(line->desc);
878 if (level < 0) {
879 pr_debug_ratelimited("debouncer failed to read line value\n");
880 return;
881 }
882
883 if (READ_ONCE(line->level) == level)
884 return;
885
886 WRITE_ONCE(line->level, level);
887
888 /* -- edge detection -- */
889 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
890 if (!eflags)
891 return;
892
893 /* switch from physical level to logical - if they differ */
894 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
895 level = !level;
896
897 /* ignore edges that are not being monitored */
898 if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) ||
899 ((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level))
900 return;
901
902 /* Do not leak kernel stack to userspace */
903 memset(&le, 0, sizeof(le));
904
905 lr = line->req;
906 le.timestamp_ns = line_event_timestamp(line);
907 le.offset = gpio_chip_hwgpio(line->desc);
908#ifdef CONFIG_HTE
909 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) {
910 /* discard events except the last one */
911 line->total_discard_seq -= 1;
912 diff_seqno = line->last_seqno - line->total_discard_seq -
913 line->line_seqno;
914 line->line_seqno = line->last_seqno - line->total_discard_seq;
915 le.line_seqno = line->line_seqno;
916 le.seqno = (lr->num_lines == 1) ?
917 le.line_seqno : atomic_add_return(diff_seqno, &lr->seqno);
918 } else
919#endif /* CONFIG_HTE */
920 {
921 line->line_seqno++;
922 le.line_seqno = line->line_seqno;
923 le.seqno = (lr->num_lines == 1) ?
924 le.line_seqno : atomic_inc_return(&lr->seqno);
925 }
926
927 le.id = line_event_id(level);
928
929 linereq_put_event(lr, &le);
930}
931
932static int debounce_setup(struct line *line, unsigned int debounce_period_us)
933{
934 unsigned long irqflags;
935 int ret, level, irq;
936
937 /* try hardware */
938 ret = gpiod_set_debounce(line->desc, debounce_period_us);
939 if (!ret) {
940 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
941 return ret;
942 }
943 if (ret != -ENOTSUPP)
944 return ret;
945
946 if (debounce_period_us) {
947 /* setup software debounce */
948 level = gpiod_get_raw_value_cansleep(line->desc);
949 if (level < 0)
950 return level;
951
952 if (!(IS_ENABLED(CONFIG_HTE) &&
953 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) {
954 irq = gpiod_to_irq(line->desc);
955 if (irq < 0)
956 return -ENXIO;
957
958 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
959 ret = request_irq(irq, debounce_irq_handler, irqflags,
960 line->req->label, line);
961 if (ret)
962 return ret;
963 line->irq = irq;
964 } else {
965 ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH);
966 if (ret)
967 return ret;
968 }
969
970 WRITE_ONCE(line->level, level);
971 WRITE_ONCE(line->sw_debounced, 1);
972 }
973 return 0;
974}
975
976static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc,
977 unsigned int line_idx)
978{
979 unsigned int i;
980 u64 mask = BIT_ULL(line_idx);
981
982 for (i = 0; i < lc->num_attrs; i++) {
983 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
984 (lc->attrs[i].mask & mask))
985 return true;
986 }
987 return false;
988}
989
990static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
991 unsigned int line_idx)
992{
993 unsigned int i;
994 u64 mask = BIT_ULL(line_idx);
995
996 for (i = 0; i < lc->num_attrs; i++) {
997 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
998 (lc->attrs[i].mask & mask))
999 return lc->attrs[i].attr.debounce_period_us;
1000 }
1001 return 0;
1002}
1003
1004static void edge_detector_stop(struct line *line)
1005{
1006 if (line->irq) {
1007 free_irq(line->irq, line);
1008 line->irq = 0;
1009 }
1010
1011#ifdef CONFIG_HTE
1012 if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
1013 hte_ts_put(&line->hdesc);
1014#endif
1015
1016 cancel_delayed_work_sync(&line->work);
1017 WRITE_ONCE(line->sw_debounced, 0);
1018 WRITE_ONCE(line->edflags, 0);
1019 if (line->desc)
1020 WRITE_ONCE(line->desc->debounce_period_us, 0);
1021 /* do not change line->level - see comment in debounced_value() */
1022}
1023
1024static int edge_detector_setup(struct line *line,
1025 struct gpio_v2_line_config *lc,
1026 unsigned int line_idx, u64 edflags)
1027{
1028 u32 debounce_period_us;
1029 unsigned long irqflags = 0;
1030 u64 eflags;
1031 int irq, ret;
1032
1033 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
1034 if (eflags && !kfifo_initialized(&line->req->events)) {
1035 ret = kfifo_alloc(&line->req->events,
1036 line->req->event_buffer_size, GFP_KERNEL);
1037 if (ret)
1038 return ret;
1039 }
1040 if (gpio_v2_line_config_debounced(lc, line_idx)) {
1041 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
1042 ret = debounce_setup(line, debounce_period_us);
1043 if (ret)
1044 return ret;
1045 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
1046 }
1047
1048 /* detection disabled or sw debouncer will provide edge detection */
1049 if (!eflags || READ_ONCE(line->sw_debounced))
1050 return 0;
1051
1052 if (IS_ENABLED(CONFIG_HTE) &&
1053 (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1054 return hte_edge_setup(line, edflags);
1055
1056 irq = gpiod_to_irq(line->desc);
1057 if (irq < 0)
1058 return -ENXIO;
1059
1060 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
1061 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
1062 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
1063 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
1064 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
1065 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
1066 irqflags |= IRQF_ONESHOT;
1067
1068 /* Request a thread to read the events */
1069 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
1070 irqflags, line->req->label, line);
1071 if (ret)
1072 return ret;
1073
1074 line->irq = irq;
1075 return 0;
1076}
1077
1078static int edge_detector_update(struct line *line,
1079 struct gpio_v2_line_config *lc,
1080 unsigned int line_idx, u64 edflags)
1081{
1082 u64 active_edflags = READ_ONCE(line->edflags);
1083 unsigned int debounce_period_us =
1084 gpio_v2_line_config_debounce_period(lc, line_idx);
1085
1086 if ((active_edflags == edflags) &&
1087 (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us))
1088 return 0;
1089
1090 /* sw debounced and still will be...*/
1091 if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
1092 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
1093 return 0;
1094 }
1095
1096 /* reconfiguring edge detection or sw debounce being disabled */
1097 if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
1098 (active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) ||
1099 (!debounce_period_us && READ_ONCE(line->sw_debounced)))
1100 edge_detector_stop(line);
1101
1102 return edge_detector_setup(line, lc, line_idx, edflags);
1103}
1104
1105static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
1106 unsigned int line_idx)
1107{
1108 unsigned int i;
1109 u64 mask = BIT_ULL(line_idx);
1110
1111 for (i = 0; i < lc->num_attrs; i++) {
1112 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) &&
1113 (lc->attrs[i].mask & mask))
1114 return lc->attrs[i].attr.flags;
1115 }
1116 return lc->flags;
1117}
1118
1119static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc,
1120 unsigned int line_idx)
1121{
1122 unsigned int i;
1123 u64 mask = BIT_ULL(line_idx);
1124
1125 for (i = 0; i < lc->num_attrs; i++) {
1126 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) &&
1127 (lc->attrs[i].mask & mask))
1128 return !!(lc->attrs[i].attr.values & mask);
1129 }
1130 return 0;
1131}
1132
1133static int gpio_v2_line_flags_validate(u64 flags)
1134{
1135 /* Return an error if an unknown flag is set */
1136 if (flags & ~GPIO_V2_LINE_VALID_FLAGS)
1137 return -EINVAL;
1138
1139 if (!IS_ENABLED(CONFIG_HTE) &&
1140 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1141 return -EOPNOTSUPP;
1142
1143 /*
1144 * Do not allow both INPUT and OUTPUT flags to be set as they are
1145 * contradictory.
1146 */
1147 if ((flags & GPIO_V2_LINE_FLAG_INPUT) &&
1148 (flags & GPIO_V2_LINE_FLAG_OUTPUT))
1149 return -EINVAL;
1150
1151 /* Only allow one event clock source */
1152 if (IS_ENABLED(CONFIG_HTE) &&
1153 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME) &&
1154 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1155 return -EINVAL;
1156
1157 /* Edge detection requires explicit input. */
1158 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) &&
1159 !(flags & GPIO_V2_LINE_FLAG_INPUT))
1160 return -EINVAL;
1161
1162 /*
1163 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single
1164 * request. If the hardware actually supports enabling both at the
1165 * same time the electrical result would be disastrous.
1166 */
1167 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) &&
1168 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE))
1169 return -EINVAL;
1170
1171 /* Drive requires explicit output direction. */
1172 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) &&
1173 !(flags & GPIO_V2_LINE_FLAG_OUTPUT))
1174 return -EINVAL;
1175
1176 /* Bias requires explicit direction. */
1177 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) &&
1178 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
1179 return -EINVAL;
1180
1181 /* Only one bias flag can be set. */
1182 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) &&
1183 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN |
1184 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) ||
1185 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) &&
1186 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)))
1187 return -EINVAL;
1188
1189 return 0;
1190}
1191
1192static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
1193 unsigned int num_lines)
1194{
1195 unsigned int i;
1196 u64 flags;
1197 int ret;
1198
1199 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX)
1200 return -EINVAL;
1201
1202 if (memchr_inv(lc->padding, 0, sizeof(lc->padding)))
1203 return -EINVAL;
1204
1205 for (i = 0; i < num_lines; i++) {
1206 flags = gpio_v2_line_config_flags(lc, i);
1207 ret = gpio_v2_line_flags_validate(flags);
1208 if (ret)
1209 return ret;
1210
1211 /* debounce requires explicit input */
1212 if (gpio_v2_line_config_debounced(lc, i) &&
1213 !(flags & GPIO_V2_LINE_FLAG_INPUT))
1214 return -EINVAL;
1215 }
1216 return 0;
1217}
1218
1219static void gpio_v2_line_config_flags_to_desc_flags(u64 flags,
1220 unsigned long *flagsp)
1221{
1222 assign_bit(FLAG_ACTIVE_LOW, flagsp,
1223 flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW);
1224
1225 if (flags & GPIO_V2_LINE_FLAG_OUTPUT)
1226 set_bit(FLAG_IS_OUT, flagsp);
1227 else if (flags & GPIO_V2_LINE_FLAG_INPUT)
1228 clear_bit(FLAG_IS_OUT, flagsp);
1229
1230 assign_bit(FLAG_EDGE_RISING, flagsp,
1231 flags & GPIO_V2_LINE_FLAG_EDGE_RISING);
1232 assign_bit(FLAG_EDGE_FALLING, flagsp,
1233 flags & GPIO_V2_LINE_FLAG_EDGE_FALLING);
1234
1235 assign_bit(FLAG_OPEN_DRAIN, flagsp,
1236 flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN);
1237 assign_bit(FLAG_OPEN_SOURCE, flagsp,
1238 flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE);
1239
1240 assign_bit(FLAG_PULL_UP, flagsp,
1241 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP);
1242 assign_bit(FLAG_PULL_DOWN, flagsp,
1243 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN);
1244 assign_bit(FLAG_BIAS_DISABLE, flagsp,
1245 flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED);
1246
1247 assign_bit(FLAG_EVENT_CLOCK_REALTIME, flagsp,
1248 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME);
1249 assign_bit(FLAG_EVENT_CLOCK_HTE, flagsp,
1250 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE);
1251}
1252
1253static long linereq_get_values(struct linereq *lr, void __user *ip)
1254{
1255 struct gpio_v2_line_values lv;
1256 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1257 struct gpio_desc **descs;
1258 unsigned int i, didx, num_get;
1259 bool val;
1260 int ret;
1261
1262 /* NOTE: It's ok to read values of output lines. */
1263 if (copy_from_user(&lv, ip, sizeof(lv)))
1264 return -EFAULT;
1265
1266 for (num_get = 0, i = 0; i < lr->num_lines; i++) {
1267 if (lv.mask & BIT_ULL(i)) {
1268 num_get++;
1269 descs = &lr->lines[i].desc;
1270 }
1271 }
1272
1273 if (num_get == 0)
1274 return -EINVAL;
1275
1276 if (num_get != 1) {
1277 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL);
1278 if (!descs)
1279 return -ENOMEM;
1280 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1281 if (lv.mask & BIT_ULL(i)) {
1282 descs[didx] = lr->lines[i].desc;
1283 didx++;
1284 }
1285 }
1286 }
1287 ret = gpiod_get_array_value_complex(false, true, num_get,
1288 descs, NULL, vals);
1289
1290 if (num_get != 1)
1291 kfree(descs);
1292 if (ret)
1293 return ret;
1294
1295 lv.bits = 0;
1296 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1297 if (lv.mask & BIT_ULL(i)) {
1298 if (lr->lines[i].sw_debounced)
1299 val = debounced_value(&lr->lines[i]);
1300 else
1301 val = test_bit(didx, vals);
1302 if (val)
1303 lv.bits |= BIT_ULL(i);
1304 didx++;
1305 }
1306 }
1307
1308 if (copy_to_user(ip, &lv, sizeof(lv)))
1309 return -EFAULT;
1310
1311 return 0;
1312}
1313
1314static long linereq_set_values_unlocked(struct linereq *lr,
1315 struct gpio_v2_line_values *lv)
1316{
1317 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1318 struct gpio_desc **descs;
1319 unsigned int i, didx, num_set;
1320 int ret;
1321
1322 bitmap_zero(vals, GPIO_V2_LINES_MAX);
1323 for (num_set = 0, i = 0; i < lr->num_lines; i++) {
1324 if (lv->mask & BIT_ULL(i)) {
1325 if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
1326 return -EPERM;
1327 if (lv->bits & BIT_ULL(i))
1328 __set_bit(num_set, vals);
1329 num_set++;
1330 descs = &lr->lines[i].desc;
1331 }
1332 }
1333 if (num_set == 0)
1334 return -EINVAL;
1335
1336 if (num_set != 1) {
1337 /* build compacted desc array and values */
1338 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);
1339 if (!descs)
1340 return -ENOMEM;
1341 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1342 if (lv->mask & BIT_ULL(i)) {
1343 descs[didx] = lr->lines[i].desc;
1344 didx++;
1345 }
1346 }
1347 }
1348 ret = gpiod_set_array_value_complex(false, true, num_set,
1349 descs, NULL, vals);
1350
1351 if (num_set != 1)
1352 kfree(descs);
1353 return ret;
1354}
1355
1356static long linereq_set_values(struct linereq *lr, void __user *ip)
1357{
1358 struct gpio_v2_line_values lv;
1359 int ret;
1360
1361 if (copy_from_user(&lv, ip, sizeof(lv)))
1362 return -EFAULT;
1363
1364 mutex_lock(&lr->config_mutex);
1365
1366 ret = linereq_set_values_unlocked(lr, &lv);
1367
1368 mutex_unlock(&lr->config_mutex);
1369
1370 return ret;
1371}
1372
1373static long linereq_set_config_unlocked(struct linereq *lr,
1374 struct gpio_v2_line_config *lc)
1375{
1376 struct gpio_desc *desc;
1377 struct line *line;
1378 unsigned int i;
1379 u64 flags, edflags;
1380 int ret;
1381
1382 for (i = 0; i < lr->num_lines; i++) {
1383 line = &lr->lines[i];
1384 desc = lr->lines[i].desc;
1385 flags = gpio_v2_line_config_flags(lc, i);
1386 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1387 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
1388 /*
1389 * Lines have to be requested explicitly for input
1390 * or output, else the line will be treated "as is".
1391 */
1392 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1393 int val = gpio_v2_line_config_output_value(lc, i);
1394
1395 edge_detector_stop(line);
1396 ret = gpiod_direction_output(desc, val);
1397 if (ret)
1398 return ret;
1399 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1400 ret = gpiod_direction_input(desc);
1401 if (ret)
1402 return ret;
1403
1404 ret = edge_detector_update(line, lc, i, edflags);
1405 if (ret)
1406 return ret;
1407 }
1408
1409 WRITE_ONCE(line->edflags, edflags);
1410
1411 blocking_notifier_call_chain(&desc->gdev->notifier,
1412 GPIO_V2_LINE_CHANGED_CONFIG,
1413 desc);
1414 }
1415 return 0;
1416}
1417
1418static long linereq_set_config(struct linereq *lr, void __user *ip)
1419{
1420 struct gpio_v2_line_config lc;
1421 int ret;
1422
1423 if (copy_from_user(&lc, ip, sizeof(lc)))
1424 return -EFAULT;
1425
1426 ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
1427 if (ret)
1428 return ret;
1429
1430 mutex_lock(&lr->config_mutex);
1431
1432 ret = linereq_set_config_unlocked(lr, &lc);
1433
1434 mutex_unlock(&lr->config_mutex);
1435
1436 return ret;
1437}
1438
1439static long linereq_ioctl_unlocked(struct file *file, unsigned int cmd,
1440 unsigned long arg)
1441{
1442 struct linereq *lr = file->private_data;
1443 void __user *ip = (void __user *)arg;
1444
1445 if (!lr->gdev->chip)
1446 return -ENODEV;
1447
1448 switch (cmd) {
1449 case GPIO_V2_LINE_GET_VALUES_IOCTL:
1450 return linereq_get_values(lr, ip);
1451 case GPIO_V2_LINE_SET_VALUES_IOCTL:
1452 return linereq_set_values(lr, ip);
1453 case GPIO_V2_LINE_SET_CONFIG_IOCTL:
1454 return linereq_set_config(lr, ip);
1455 default:
1456 return -EINVAL;
1457 }
1458}
1459
1460static long linereq_ioctl(struct file *file, unsigned int cmd,
1461 unsigned long arg)
1462{
1463 struct linereq *lr = file->private_data;
1464
1465 return call_ioctl_locked(file, cmd, arg, lr->gdev,
1466 linereq_ioctl_unlocked);
1467}
1468
1469#ifdef CONFIG_COMPAT
1470static long linereq_ioctl_compat(struct file *file, unsigned int cmd,
1471 unsigned long arg)
1472{
1473 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1474}
1475#endif
1476
1477static __poll_t linereq_poll_unlocked(struct file *file,
1478 struct poll_table_struct *wait)
1479{
1480 struct linereq *lr = file->private_data;
1481 __poll_t events = 0;
1482
1483 if (!lr->gdev->chip)
1484 return EPOLLHUP | EPOLLERR;
1485
1486 poll_wait(file, &lr->wait, wait);
1487
1488 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events,
1489 &lr->wait.lock))
1490 events = EPOLLIN | EPOLLRDNORM;
1491
1492 return events;
1493}
1494
1495static __poll_t linereq_poll(struct file *file,
1496 struct poll_table_struct *wait)
1497{
1498 struct linereq *lr = file->private_data;
1499
1500 return call_poll_locked(file, wait, lr->gdev, linereq_poll_unlocked);
1501}
1502
1503static ssize_t linereq_read_unlocked(struct file *file, char __user *buf,
1504 size_t count, loff_t *f_ps)
1505{
1506 struct linereq *lr = file->private_data;
1507 struct gpio_v2_line_event le;
1508 ssize_t bytes_read = 0;
1509 int ret;
1510
1511 if (!lr->gdev->chip)
1512 return -ENODEV;
1513
1514 if (count < sizeof(le))
1515 return -EINVAL;
1516
1517 do {
1518 spin_lock(&lr->wait.lock);
1519 if (kfifo_is_empty(&lr->events)) {
1520 if (bytes_read) {
1521 spin_unlock(&lr->wait.lock);
1522 return bytes_read;
1523 }
1524
1525 if (file->f_flags & O_NONBLOCK) {
1526 spin_unlock(&lr->wait.lock);
1527 return -EAGAIN;
1528 }
1529
1530 ret = wait_event_interruptible_locked(lr->wait,
1531 !kfifo_is_empty(&lr->events));
1532 if (ret) {
1533 spin_unlock(&lr->wait.lock);
1534 return ret;
1535 }
1536 }
1537
1538 ret = kfifo_out(&lr->events, &le, 1);
1539 spin_unlock(&lr->wait.lock);
1540 if (ret != 1) {
1541 /*
1542 * This should never happen - we were holding the
1543 * lock from the moment we learned the fifo is no
1544 * longer empty until now.
1545 */
1546 ret = -EIO;
1547 break;
1548 }
1549
1550 if (copy_to_user(buf + bytes_read, &le, sizeof(le)))
1551 return -EFAULT;
1552 bytes_read += sizeof(le);
1553 } while (count >= bytes_read + sizeof(le));
1554
1555 return bytes_read;
1556}
1557
1558static ssize_t linereq_read(struct file *file, char __user *buf,
1559 size_t count, loff_t *f_ps)
1560{
1561 struct linereq *lr = file->private_data;
1562
1563 return call_read_locked(file, buf, count, f_ps, lr->gdev,
1564 linereq_read_unlocked);
1565}
1566
1567static void linereq_free(struct linereq *lr)
1568{
1569 unsigned int i;
1570
1571 for (i = 0; i < lr->num_lines; i++) {
1572 if (lr->lines[i].desc) {
1573 edge_detector_stop(&lr->lines[i]);
1574 gpiod_free(lr->lines[i].desc);
1575 }
1576 }
1577 kfifo_free(&lr->events);
1578 kfree(lr->label);
1579 put_device(&lr->gdev->dev);
1580 kfree(lr);
1581}
1582
1583static int linereq_release(struct inode *inode, struct file *file)
1584{
1585 struct linereq *lr = file->private_data;
1586
1587 linereq_free(lr);
1588 return 0;
1589}
1590
1591#ifdef CONFIG_PROC_FS
1592static void linereq_show_fdinfo(struct seq_file *out, struct file *file)
1593{
1594 struct linereq *lr = file->private_data;
1595 struct device *dev = &lr->gdev->dev;
1596 u16 i;
1597
1598 seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev));
1599
1600 for (i = 0; i < lr->num_lines; i++)
1601 seq_printf(out, "gpio-line:\t%d\n",
1602 gpio_chip_hwgpio(lr->lines[i].desc));
1603}
1604#endif
1605
1606static const struct file_operations line_fileops = {
1607 .release = linereq_release,
1608 .read = linereq_read,
1609 .poll = linereq_poll,
1610 .owner = THIS_MODULE,
1611 .llseek = noop_llseek,
1612 .unlocked_ioctl = linereq_ioctl,
1613#ifdef CONFIG_COMPAT
1614 .compat_ioctl = linereq_ioctl_compat,
1615#endif
1616#ifdef CONFIG_PROC_FS
1617 .show_fdinfo = linereq_show_fdinfo,
1618#endif
1619};
1620
1621static int linereq_create(struct gpio_device *gdev, void __user *ip)
1622{
1623 struct gpio_v2_line_request ulr;
1624 struct gpio_v2_line_config *lc;
1625 struct linereq *lr;
1626 struct file *file;
1627 u64 flags, edflags;
1628 unsigned int i;
1629 int fd, ret;
1630
1631 if (copy_from_user(&ulr, ip, sizeof(ulr)))
1632 return -EFAULT;
1633
1634 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
1635 return -EINVAL;
1636
1637 if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding)))
1638 return -EINVAL;
1639
1640 lc = &ulr.config;
1641 ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
1642 if (ret)
1643 return ret;
1644
1645 lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
1646 if (!lr)
1647 return -ENOMEM;
1648
1649 lr->gdev = gdev;
1650 get_device(&gdev->dev);
1651
1652 for (i = 0; i < ulr.num_lines; i++) {
1653 lr->lines[i].req = lr;
1654 WRITE_ONCE(lr->lines[i].sw_debounced, 0);
1655 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
1656 }
1657
1658 if (ulr.consumer[0] != '\0') {
1659 /* label is only initialized if consumer is set */
1660 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
1661 GFP_KERNEL);
1662 if (!lr->label) {
1663 ret = -ENOMEM;
1664 goto out_free_linereq;
1665 }
1666 }
1667
1668 mutex_init(&lr->config_mutex);
1669 init_waitqueue_head(&lr->wait);
1670 lr->event_buffer_size = ulr.event_buffer_size;
1671 if (lr->event_buffer_size == 0)
1672 lr->event_buffer_size = ulr.num_lines * 16;
1673 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16)
1674 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;
1675
1676 atomic_set(&lr->seqno, 0);
1677 lr->num_lines = ulr.num_lines;
1678
1679 /* Request each GPIO */
1680 for (i = 0; i < ulr.num_lines; i++) {
1681 u32 offset = ulr.offsets[i];
1682 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
1683
1684 if (IS_ERR(desc)) {
1685 ret = PTR_ERR(desc);
1686 goto out_free_linereq;
1687 }
1688
1689 ret = gpiod_request_user(desc, lr->label);
1690 if (ret)
1691 goto out_free_linereq;
1692
1693 lr->lines[i].desc = desc;
1694 flags = gpio_v2_line_config_flags(lc, i);
1695 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1696
1697 ret = gpiod_set_transitory(desc, false);
1698 if (ret < 0)
1699 goto out_free_linereq;
1700
1701 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
1702 /*
1703 * Lines have to be requested explicitly for input
1704 * or output, else the line will be treated "as is".
1705 */
1706 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1707 int val = gpio_v2_line_config_output_value(lc, i);
1708
1709 ret = gpiod_direction_output(desc, val);
1710 if (ret)
1711 goto out_free_linereq;
1712 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1713 ret = gpiod_direction_input(desc);
1714 if (ret)
1715 goto out_free_linereq;
1716
1717 ret = edge_detector_setup(&lr->lines[i], lc, i,
1718 edflags);
1719 if (ret)
1720 goto out_free_linereq;
1721 }
1722
1723 lr->lines[i].edflags = edflags;
1724
1725 blocking_notifier_call_chain(&desc->gdev->notifier,
1726 GPIO_V2_LINE_CHANGED_REQUESTED, desc);
1727
1728 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
1729 offset);
1730 }
1731
1732 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
1733 if (fd < 0) {
1734 ret = fd;
1735 goto out_free_linereq;
1736 }
1737
1738 file = anon_inode_getfile("gpio-line", &line_fileops, lr,
1739 O_RDONLY | O_CLOEXEC);
1740 if (IS_ERR(file)) {
1741 ret = PTR_ERR(file);
1742 goto out_put_unused_fd;
1743 }
1744
1745 ulr.fd = fd;
1746 if (copy_to_user(ip, &ulr, sizeof(ulr))) {
1747 /*
1748 * fput() will trigger the release() callback, so do not go onto
1749 * the regular error cleanup path here.
1750 */
1751 fput(file);
1752 put_unused_fd(fd);
1753 return -EFAULT;
1754 }
1755
1756 fd_install(fd, file);
1757
1758 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
1759 lr->num_lines);
1760
1761 return 0;
1762
1763out_put_unused_fd:
1764 put_unused_fd(fd);
1765out_free_linereq:
1766 linereq_free(lr);
1767 return ret;
1768}
1769
1770#ifdef CONFIG_GPIO_CDEV_V1
1771
1772/*
1773 * GPIO line event management
1774 */
1775
1776/**
1777 * struct lineevent_state - contains the state of a userspace event
1778 * @gdev: the GPIO device the event pertains to
1779 * @label: consumer label used to tag descriptors
1780 * @desc: the GPIO descriptor held by this event
1781 * @eflags: the event flags this line was requested with
1782 * @irq: the interrupt that trigger in response to events on this GPIO
1783 * @wait: wait queue that handles blocking reads of events
1784 * @events: KFIFO for the GPIO events
1785 * @timestamp: cache for the timestamp storing it between hardirq
1786 * and IRQ thread, used to bring the timestamp close to the actual
1787 * event
1788 */
1789struct lineevent_state {
1790 struct gpio_device *gdev;
1791 const char *label;
1792 struct gpio_desc *desc;
1793 u32 eflags;
1794 int irq;
1795 wait_queue_head_t wait;
1796 DECLARE_KFIFO(events, struct gpioevent_data, 16);
1797 u64 timestamp;
1798};
1799
1800#define GPIOEVENT_REQUEST_VALID_FLAGS \
1801 (GPIOEVENT_REQUEST_RISING_EDGE | \
1802 GPIOEVENT_REQUEST_FALLING_EDGE)
1803
1804static __poll_t lineevent_poll_unlocked(struct file *file,
1805 struct poll_table_struct *wait)
1806{
1807 struct lineevent_state *le = file->private_data;
1808 __poll_t events = 0;
1809
1810 if (!le->gdev->chip)
1811 return EPOLLHUP | EPOLLERR;
1812
1813 poll_wait(file, &le->wait, wait);
1814
1815 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
1816 events = EPOLLIN | EPOLLRDNORM;
1817
1818 return events;
1819}
1820
1821static __poll_t lineevent_poll(struct file *file,
1822 struct poll_table_struct *wait)
1823{
1824 struct lineevent_state *le = file->private_data;
1825
1826 return call_poll_locked(file, wait, le->gdev, lineevent_poll_unlocked);
1827}
1828
1829struct compat_gpioeevent_data {
1830 compat_u64 timestamp;
1831 u32 id;
1832};
1833
1834static ssize_t lineevent_read_unlocked(struct file *file, char __user *buf,
1835 size_t count, loff_t *f_ps)
1836{
1837 struct lineevent_state *le = file->private_data;
1838 struct gpioevent_data ge;
1839 ssize_t bytes_read = 0;
1840 ssize_t ge_size;
1841 int ret;
1842
1843 if (!le->gdev->chip)
1844 return -ENODEV;
1845
1846 /*
1847 * When compatible system call is being used the struct gpioevent_data,
1848 * in case of at least ia32, has different size due to the alignment
1849 * differences. Because we have first member 64 bits followed by one of
1850 * 32 bits there is no gap between them. The only difference is the
1851 * padding at the end of the data structure. Hence, we calculate the
1852 * actual sizeof() and pass this as an argument to copy_to_user() to
1853 * drop unneeded bytes from the output.
1854 */
1855 if (compat_need_64bit_alignment_fixup())
1856 ge_size = sizeof(struct compat_gpioeevent_data);
1857 else
1858 ge_size = sizeof(struct gpioevent_data);
1859 if (count < ge_size)
1860 return -EINVAL;
1861
1862 do {
1863 spin_lock(&le->wait.lock);
1864 if (kfifo_is_empty(&le->events)) {
1865 if (bytes_read) {
1866 spin_unlock(&le->wait.lock);
1867 return bytes_read;
1868 }
1869
1870 if (file->f_flags & O_NONBLOCK) {
1871 spin_unlock(&le->wait.lock);
1872 return -EAGAIN;
1873 }
1874
1875 ret = wait_event_interruptible_locked(le->wait,
1876 !kfifo_is_empty(&le->events));
1877 if (ret) {
1878 spin_unlock(&le->wait.lock);
1879 return ret;
1880 }
1881 }
1882
1883 ret = kfifo_out(&le->events, &ge, 1);
1884 spin_unlock(&le->wait.lock);
1885 if (ret != 1) {
1886 /*
1887 * This should never happen - we were holding the lock
1888 * from the moment we learned the fifo is no longer
1889 * empty until now.
1890 */
1891 ret = -EIO;
1892 break;
1893 }
1894
1895 if (copy_to_user(buf + bytes_read, &ge, ge_size))
1896 return -EFAULT;
1897 bytes_read += ge_size;
1898 } while (count >= bytes_read + ge_size);
1899
1900 return bytes_read;
1901}
1902
1903static ssize_t lineevent_read(struct file *file, char __user *buf,
1904 size_t count, loff_t *f_ps)
1905{
1906 struct lineevent_state *le = file->private_data;
1907
1908 return call_read_locked(file, buf, count, f_ps, le->gdev,
1909 lineevent_read_unlocked);
1910}
1911
1912static void lineevent_free(struct lineevent_state *le)
1913{
1914 if (le->irq)
1915 free_irq(le->irq, le);
1916 if (le->desc)
1917 gpiod_free(le->desc);
1918 kfree(le->label);
1919 put_device(&le->gdev->dev);
1920 kfree(le);
1921}
1922
1923static int lineevent_release(struct inode *inode, struct file *file)
1924{
1925 lineevent_free(file->private_data);
1926 return 0;
1927}
1928
1929static long lineevent_ioctl_unlocked(struct file *file, unsigned int cmd,
1930 unsigned long arg)
1931{
1932 struct lineevent_state *le = file->private_data;
1933 void __user *ip = (void __user *)arg;
1934 struct gpiohandle_data ghd;
1935
1936 if (!le->gdev->chip)
1937 return -ENODEV;
1938
1939 /*
1940 * We can get the value for an event line but not set it,
1941 * because it is input by definition.
1942 */
1943 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
1944 int val;
1945
1946 memset(&ghd, 0, sizeof(ghd));
1947
1948 val = gpiod_get_value_cansleep(le->desc);
1949 if (val < 0)
1950 return val;
1951 ghd.values[0] = val;
1952
1953 if (copy_to_user(ip, &ghd, sizeof(ghd)))
1954 return -EFAULT;
1955
1956 return 0;
1957 }
1958 return -EINVAL;
1959}
1960
1961static long lineevent_ioctl(struct file *file, unsigned int cmd,
1962 unsigned long arg)
1963{
1964 struct lineevent_state *le = file->private_data;
1965
1966 return call_ioctl_locked(file, cmd, arg, le->gdev,
1967 lineevent_ioctl_unlocked);
1968}
1969
1970#ifdef CONFIG_COMPAT
1971static long lineevent_ioctl_compat(struct file *file, unsigned int cmd,
1972 unsigned long arg)
1973{
1974 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1975}
1976#endif
1977
1978static const struct file_operations lineevent_fileops = {
1979 .release = lineevent_release,
1980 .read = lineevent_read,
1981 .poll = lineevent_poll,
1982 .owner = THIS_MODULE,
1983 .llseek = noop_llseek,
1984 .unlocked_ioctl = lineevent_ioctl,
1985#ifdef CONFIG_COMPAT
1986 .compat_ioctl = lineevent_ioctl_compat,
1987#endif
1988};
1989
1990static irqreturn_t lineevent_irq_thread(int irq, void *p)
1991{
1992 struct lineevent_state *le = p;
1993 struct gpioevent_data ge;
1994 int ret;
1995
1996 /* Do not leak kernel stack to userspace */
1997 memset(&ge, 0, sizeof(ge));
1998
1999 /*
2000 * We may be running from a nested threaded interrupt in which case
2001 * we didn't get the timestamp from lineevent_irq_handler().
2002 */
2003 if (!le->timestamp)
2004 ge.timestamp = ktime_get_ns();
2005 else
2006 ge.timestamp = le->timestamp;
2007
2008 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
2009 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
2010 int level = gpiod_get_value_cansleep(le->desc);
2011
2012 if (level)
2013 /* Emit low-to-high event */
2014 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
2015 else
2016 /* Emit high-to-low event */
2017 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
2018 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
2019 /* Emit low-to-high event */
2020 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
2021 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
2022 /* Emit high-to-low event */
2023 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
2024 } else {
2025 return IRQ_NONE;
2026 }
2027
2028 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
2029 1, &le->wait.lock);
2030 if (ret)
2031 wake_up_poll(&le->wait, EPOLLIN);
2032 else
2033 pr_debug_ratelimited("event FIFO is full - event dropped\n");
2034
2035 return IRQ_HANDLED;
2036}
2037
2038static irqreturn_t lineevent_irq_handler(int irq, void *p)
2039{
2040 struct lineevent_state *le = p;
2041
2042 /*
2043 * Just store the timestamp in hardirq context so we get it as
2044 * close in time as possible to the actual event.
2045 */
2046 le->timestamp = ktime_get_ns();
2047
2048 return IRQ_WAKE_THREAD;
2049}
2050
2051static int lineevent_create(struct gpio_device *gdev, void __user *ip)
2052{
2053 struct gpioevent_request eventreq;
2054 struct lineevent_state *le;
2055 struct gpio_desc *desc;
2056 struct file *file;
2057 u32 offset;
2058 u32 lflags;
2059 u32 eflags;
2060 int fd;
2061 int ret;
2062 int irq, irqflags = 0;
2063
2064 if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
2065 return -EFAULT;
2066
2067 offset = eventreq.lineoffset;
2068 lflags = eventreq.handleflags;
2069 eflags = eventreq.eventflags;
2070
2071 desc = gpiochip_get_desc(gdev->chip, offset);
2072 if (IS_ERR(desc))
2073 return PTR_ERR(desc);
2074
2075 /* Return an error if a unknown flag is set */
2076 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
2077 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
2078 return -EINVAL;
2079
2080 /* This is just wrong: we don't look for events on output lines */
2081 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
2082 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
2083 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
2084 return -EINVAL;
2085
2086 /* Only one bias flag can be set. */
2087 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
2088 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
2089 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
2090 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
2091 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
2092 return -EINVAL;
2093
2094 le = kzalloc(sizeof(*le), GFP_KERNEL);
2095 if (!le)
2096 return -ENOMEM;
2097 le->gdev = gdev;
2098 get_device(&gdev->dev);
2099
2100 if (eventreq.consumer_label[0] != '\0') {
2101 /* label is only initialized if consumer_label is set */
2102 le->label = kstrndup(eventreq.consumer_label,
2103 sizeof(eventreq.consumer_label) - 1,
2104 GFP_KERNEL);
2105 if (!le->label) {
2106 ret = -ENOMEM;
2107 goto out_free_le;
2108 }
2109 }
2110
2111 ret = gpiod_request_user(desc, le->label);
2112 if (ret)
2113 goto out_free_le;
2114 le->desc = desc;
2115 le->eflags = eflags;
2116
2117 linehandle_flags_to_desc_flags(lflags, &desc->flags);
2118
2119 ret = gpiod_direction_input(desc);
2120 if (ret)
2121 goto out_free_le;
2122
2123 blocking_notifier_call_chain(&desc->gdev->notifier,
2124 GPIO_V2_LINE_CHANGED_REQUESTED, desc);
2125
2126 irq = gpiod_to_irq(desc);
2127 if (irq <= 0) {
2128 ret = -ENODEV;
2129 goto out_free_le;
2130 }
2131
2132 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
2133 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
2134 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
2135 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
2136 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
2137 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
2138 irqflags |= IRQF_ONESHOT;
2139
2140 INIT_KFIFO(le->events);
2141 init_waitqueue_head(&le->wait);
2142
2143 /* Request a thread to read the events */
2144 ret = request_threaded_irq(irq,
2145 lineevent_irq_handler,
2146 lineevent_irq_thread,
2147 irqflags,
2148 le->label,
2149 le);
2150 if (ret)
2151 goto out_free_le;
2152
2153 le->irq = irq;
2154
2155 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
2156 if (fd < 0) {
2157 ret = fd;
2158 goto out_free_le;
2159 }
2160
2161 file = anon_inode_getfile("gpio-event",
2162 &lineevent_fileops,
2163 le,
2164 O_RDONLY | O_CLOEXEC);
2165 if (IS_ERR(file)) {
2166 ret = PTR_ERR(file);
2167 goto out_put_unused_fd;
2168 }
2169
2170 eventreq.fd = fd;
2171 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) {
2172 /*
2173 * fput() will trigger the release() callback, so do not go onto
2174 * the regular error cleanup path here.
2175 */
2176 fput(file);
2177 put_unused_fd(fd);
2178 return -EFAULT;
2179 }
2180
2181 fd_install(fd, file);
2182
2183 return 0;
2184
2185out_put_unused_fd:
2186 put_unused_fd(fd);
2187out_free_le:
2188 lineevent_free(le);
2189 return ret;
2190}
2191
2192static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2,
2193 struct gpioline_info *info_v1)
2194{
2195 u64 flagsv2 = info_v2->flags;
2196
2197 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name));
2198 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer));
2199 info_v1->line_offset = info_v2->offset;
2200 info_v1->flags = 0;
2201
2202 if (flagsv2 & GPIO_V2_LINE_FLAG_USED)
2203 info_v1->flags |= GPIOLINE_FLAG_KERNEL;
2204
2205 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT)
2206 info_v1->flags |= GPIOLINE_FLAG_IS_OUT;
2207
2208 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
2209 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
2210
2211 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN)
2212 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN;
2213 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE)
2214 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE;
2215
2216 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)
2217 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
2218 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN)
2219 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
2220 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED)
2221 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
2222}
2223
2224static void gpio_v2_line_info_changed_to_v1(
2225 struct gpio_v2_line_info_changed *lic_v2,
2226 struct gpioline_info_changed *lic_v1)
2227{
2228 memset(lic_v1, 0, sizeof(*lic_v1));
2229 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info);
2230 lic_v1->timestamp = lic_v2->timestamp_ns;
2231 lic_v1->event_type = lic_v2->event_type;
2232}
2233
2234#endif /* CONFIG_GPIO_CDEV_V1 */
2235
2236static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
2237 struct gpio_v2_line_info *info)
2238{
2239 struct gpio_chip *gc = desc->gdev->chip;
2240 bool ok_for_pinctrl;
2241 unsigned long flags;
2242 u32 debounce_period_us;
2243 unsigned int num_attrs = 0;
2244
2245 memset(info, 0, sizeof(*info));
2246 info->offset = gpio_chip_hwgpio(desc);
2247
2248 /*
2249 * This function takes a mutex so we must check this before taking
2250 * the spinlock.
2251 *
2252 * FIXME: find a non-racy way to retrieve this information. Maybe a
2253 * lock common to both frameworks?
2254 */
2255 ok_for_pinctrl =
2256 pinctrl_gpio_can_use_line(gc->base + info->offset);
2257
2258 spin_lock_irqsave(&gpio_lock, flags);
2259
2260 if (desc->name)
2261 strscpy(info->name, desc->name, sizeof(info->name));
2262
2263 if (desc->label)
2264 strscpy(info->consumer, desc->label, sizeof(info->consumer));
2265
2266 /*
2267 * Userspace only need to know that the kernel is using this GPIO so
2268 * it can't use it.
2269 */
2270 info->flags = 0;
2271 if (test_bit(FLAG_REQUESTED, &desc->flags) ||
2272 test_bit(FLAG_IS_HOGGED, &desc->flags) ||
2273 test_bit(FLAG_USED_AS_IRQ, &desc->flags) ||
2274 test_bit(FLAG_EXPORT, &desc->flags) ||
2275 test_bit(FLAG_SYSFS, &desc->flags) ||
2276 !gpiochip_line_is_valid(gc, info->offset) ||
2277 !ok_for_pinctrl)
2278 info->flags |= GPIO_V2_LINE_FLAG_USED;
2279
2280 if (test_bit(FLAG_IS_OUT, &desc->flags))
2281 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
2282 else
2283 info->flags |= GPIO_V2_LINE_FLAG_INPUT;
2284
2285 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
2286 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
2287
2288 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
2289 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
2290 if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
2291 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
2292
2293 if (test_bit(FLAG_BIAS_DISABLE, &desc->flags))
2294 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
2295 if (test_bit(FLAG_PULL_DOWN, &desc->flags))
2296 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
2297 if (test_bit(FLAG_PULL_UP, &desc->flags))
2298 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
2299
2300 if (test_bit(FLAG_EDGE_RISING, &desc->flags))
2301 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
2302 if (test_bit(FLAG_EDGE_FALLING, &desc->flags))
2303 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
2304
2305 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &desc->flags))
2306 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME;
2307 else if (test_bit(FLAG_EVENT_CLOCK_HTE, &desc->flags))
2308 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE;
2309
2310 debounce_period_us = READ_ONCE(desc->debounce_period_us);
2311 if (debounce_period_us) {
2312 info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
2313 info->attrs[num_attrs].debounce_period_us = debounce_period_us;
2314 num_attrs++;
2315 }
2316 info->num_attrs = num_attrs;
2317
2318 spin_unlock_irqrestore(&gpio_lock, flags);
2319}
2320
2321struct gpio_chardev_data {
2322 struct gpio_device *gdev;
2323 wait_queue_head_t wait;
2324 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32);
2325 struct notifier_block lineinfo_changed_nb;
2326 unsigned long *watched_lines;
2327#ifdef CONFIG_GPIO_CDEV_V1
2328 atomic_t watch_abi_version;
2329#endif
2330};
2331
2332static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip)
2333{
2334 struct gpio_device *gdev = cdev->gdev;
2335 struct gpiochip_info chipinfo;
2336
2337 memset(&chipinfo, 0, sizeof(chipinfo));
2338
2339 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name));
2340 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label));
2341 chipinfo.lines = gdev->ngpio;
2342 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
2343 return -EFAULT;
2344 return 0;
2345}
2346
2347#ifdef CONFIG_GPIO_CDEV_V1
2348/*
2349 * returns 0 if the versions match, else the previously selected ABI version
2350 */
2351static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata,
2352 unsigned int version)
2353{
2354 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version);
2355
2356 if (abiv == version)
2357 return 0;
2358
2359 return abiv;
2360}
2361
2362static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
2363 bool watch)
2364{
2365 struct gpio_desc *desc;
2366 struct gpioline_info lineinfo;
2367 struct gpio_v2_line_info lineinfo_v2;
2368
2369 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2370 return -EFAULT;
2371
2372 /* this doubles as a range check on line_offset */
2373 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset);
2374 if (IS_ERR(desc))
2375 return PTR_ERR(desc);
2376
2377 if (watch) {
2378 if (lineinfo_ensure_abi_version(cdev, 1))
2379 return -EPERM;
2380
2381 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
2382 return -EBUSY;
2383 }
2384
2385 gpio_desc_to_lineinfo(desc, &lineinfo_v2);
2386 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
2387
2388 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2389 if (watch)
2390 clear_bit(lineinfo.line_offset, cdev->watched_lines);
2391 return -EFAULT;
2392 }
2393
2394 return 0;
2395}
2396#endif
2397
2398static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
2399 bool watch)
2400{
2401 struct gpio_desc *desc;
2402 struct gpio_v2_line_info lineinfo;
2403
2404 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2405 return -EFAULT;
2406
2407 if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding)))
2408 return -EINVAL;
2409
2410 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset);
2411 if (IS_ERR(desc))
2412 return PTR_ERR(desc);
2413
2414 if (watch) {
2415#ifdef CONFIG_GPIO_CDEV_V1
2416 if (lineinfo_ensure_abi_version(cdev, 2))
2417 return -EPERM;
2418#endif
2419 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
2420 return -EBUSY;
2421 }
2422 gpio_desc_to_lineinfo(desc, &lineinfo);
2423
2424 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2425 if (watch)
2426 clear_bit(lineinfo.offset, cdev->watched_lines);
2427 return -EFAULT;
2428 }
2429
2430 return 0;
2431}
2432
2433static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip)
2434{
2435 __u32 offset;
2436
2437 if (copy_from_user(&offset, ip, sizeof(offset)))
2438 return -EFAULT;
2439
2440 if (offset >= cdev->gdev->ngpio)
2441 return -EINVAL;
2442
2443 if (!test_and_clear_bit(offset, cdev->watched_lines))
2444 return -EBUSY;
2445
2446 return 0;
2447}
2448
2449/*
2450 * gpio_ioctl() - ioctl handler for the GPIO chardev
2451 */
2452static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2453{
2454 struct gpio_chardev_data *cdev = file->private_data;
2455 struct gpio_device *gdev = cdev->gdev;
2456 void __user *ip = (void __user *)arg;
2457
2458 /* We fail any subsequent ioctl():s when the chip is gone */
2459 if (!gdev->chip)
2460 return -ENODEV;
2461
2462 /* Fill in the struct and pass to userspace */
2463 switch (cmd) {
2464 case GPIO_GET_CHIPINFO_IOCTL:
2465 return chipinfo_get(cdev, ip);
2466#ifdef CONFIG_GPIO_CDEV_V1
2467 case GPIO_GET_LINEHANDLE_IOCTL:
2468 return linehandle_create(gdev, ip);
2469 case GPIO_GET_LINEEVENT_IOCTL:
2470 return lineevent_create(gdev, ip);
2471 case GPIO_GET_LINEINFO_IOCTL:
2472 return lineinfo_get_v1(cdev, ip, false);
2473 case GPIO_GET_LINEINFO_WATCH_IOCTL:
2474 return lineinfo_get_v1(cdev, ip, true);
2475#endif /* CONFIG_GPIO_CDEV_V1 */
2476 case GPIO_V2_GET_LINEINFO_IOCTL:
2477 return lineinfo_get(cdev, ip, false);
2478 case GPIO_V2_GET_LINEINFO_WATCH_IOCTL:
2479 return lineinfo_get(cdev, ip, true);
2480 case GPIO_V2_GET_LINE_IOCTL:
2481 return linereq_create(gdev, ip);
2482 case GPIO_GET_LINEINFO_UNWATCH_IOCTL:
2483 return lineinfo_unwatch(cdev, ip);
2484 default:
2485 return -EINVAL;
2486 }
2487}
2488
2489#ifdef CONFIG_COMPAT
2490static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
2491 unsigned long arg)
2492{
2493 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2494}
2495#endif
2496
2497static struct gpio_chardev_data *
2498to_gpio_chardev_data(struct notifier_block *nb)
2499{
2500 return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
2501}
2502
2503static int lineinfo_changed_notify(struct notifier_block *nb,
2504 unsigned long action, void *data)
2505{
2506 struct gpio_chardev_data *cdev = to_gpio_chardev_data(nb);
2507 struct gpio_v2_line_info_changed chg;
2508 struct gpio_desc *desc = data;
2509 int ret;
2510
2511 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines))
2512 return NOTIFY_DONE;
2513
2514 memset(&chg, 0, sizeof(chg));
2515 chg.event_type = action;
2516 chg.timestamp_ns = ktime_get_ns();
2517 gpio_desc_to_lineinfo(desc, &chg.info);
2518
2519 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
2520 if (ret)
2521 wake_up_poll(&cdev->wait, EPOLLIN);
2522 else
2523 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");
2524
2525 return NOTIFY_OK;
2526}
2527
2528static __poll_t lineinfo_watch_poll_unlocked(struct file *file,
2529 struct poll_table_struct *pollt)
2530{
2531 struct gpio_chardev_data *cdev = file->private_data;
2532 __poll_t events = 0;
2533
2534 if (!cdev->gdev->chip)
2535 return EPOLLHUP | EPOLLERR;
2536
2537 poll_wait(file, &cdev->wait, pollt);
2538
2539 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events,
2540 &cdev->wait.lock))
2541 events = EPOLLIN | EPOLLRDNORM;
2542
2543 return events;
2544}
2545
2546static __poll_t lineinfo_watch_poll(struct file *file,
2547 struct poll_table_struct *pollt)
2548{
2549 struct gpio_chardev_data *cdev = file->private_data;
2550
2551 return call_poll_locked(file, pollt, cdev->gdev,
2552 lineinfo_watch_poll_unlocked);
2553}
2554
2555static ssize_t lineinfo_watch_read_unlocked(struct file *file, char __user *buf,
2556 size_t count, loff_t *off)
2557{
2558 struct gpio_chardev_data *cdev = file->private_data;
2559 struct gpio_v2_line_info_changed event;
2560 ssize_t bytes_read = 0;
2561 int ret;
2562 size_t event_size;
2563
2564 if (!cdev->gdev->chip)
2565 return -ENODEV;
2566
2567#ifndef CONFIG_GPIO_CDEV_V1
2568 event_size = sizeof(struct gpio_v2_line_info_changed);
2569 if (count < event_size)
2570 return -EINVAL;
2571#endif
2572
2573 do {
2574 spin_lock(&cdev->wait.lock);
2575 if (kfifo_is_empty(&cdev->events)) {
2576 if (bytes_read) {
2577 spin_unlock(&cdev->wait.lock);
2578 return bytes_read;
2579 }
2580
2581 if (file->f_flags & O_NONBLOCK) {
2582 spin_unlock(&cdev->wait.lock);
2583 return -EAGAIN;
2584 }
2585
2586 ret = wait_event_interruptible_locked(cdev->wait,
2587 !kfifo_is_empty(&cdev->events));
2588 if (ret) {
2589 spin_unlock(&cdev->wait.lock);
2590 return ret;
2591 }
2592 }
2593#ifdef CONFIG_GPIO_CDEV_V1
2594 /* must be after kfifo check so watch_abi_version is set */
2595 if (atomic_read(&cdev->watch_abi_version) == 2)
2596 event_size = sizeof(struct gpio_v2_line_info_changed);
2597 else
2598 event_size = sizeof(struct gpioline_info_changed);
2599 if (count < event_size) {
2600 spin_unlock(&cdev->wait.lock);
2601 return -EINVAL;
2602 }
2603#endif
2604 ret = kfifo_out(&cdev->events, &event, 1);
2605 spin_unlock(&cdev->wait.lock);
2606 if (ret != 1) {
2607 ret = -EIO;
2608 break;
2609 /* We should never get here. See lineevent_read(). */
2610 }
2611
2612#ifdef CONFIG_GPIO_CDEV_V1
2613 if (event_size == sizeof(struct gpio_v2_line_info_changed)) {
2614 if (copy_to_user(buf + bytes_read, &event, event_size))
2615 return -EFAULT;
2616 } else {
2617 struct gpioline_info_changed event_v1;
2618
2619 gpio_v2_line_info_changed_to_v1(&event, &event_v1);
2620 if (copy_to_user(buf + bytes_read, &event_v1,
2621 event_size))
2622 return -EFAULT;
2623 }
2624#else
2625 if (copy_to_user(buf + bytes_read, &event, event_size))
2626 return -EFAULT;
2627#endif
2628 bytes_read += event_size;
2629 } while (count >= bytes_read + sizeof(event));
2630
2631 return bytes_read;
2632}
2633
2634static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
2635 size_t count, loff_t *off)
2636{
2637 struct gpio_chardev_data *cdev = file->private_data;
2638
2639 return call_read_locked(file, buf, count, off, cdev->gdev,
2640 lineinfo_watch_read_unlocked);
2641}
2642
2643/**
2644 * gpio_chrdev_open() - open the chardev for ioctl operations
2645 * @inode: inode for this chardev
2646 * @file: file struct for storing private data
2647 * Returns 0 on success
2648 */
2649static int gpio_chrdev_open(struct inode *inode, struct file *file)
2650{
2651 struct gpio_device *gdev = container_of(inode->i_cdev,
2652 struct gpio_device, chrdev);
2653 struct gpio_chardev_data *cdev;
2654 int ret = -ENOMEM;
2655
2656 down_read(&gdev->sem);
2657
2658 /* Fail on open if the backing gpiochip is gone */
2659 if (!gdev->chip) {
2660 ret = -ENODEV;
2661 goto out_unlock;
2662 }
2663
2664 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
2665 if (!cdev)
2666 goto out_unlock;
2667
2668 cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL);
2669 if (!cdev->watched_lines)
2670 goto out_free_cdev;
2671
2672 init_waitqueue_head(&cdev->wait);
2673 INIT_KFIFO(cdev->events);
2674 cdev->gdev = gdev;
2675
2676 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
2677 ret = blocking_notifier_chain_register(&gdev->notifier,
2678 &cdev->lineinfo_changed_nb);
2679 if (ret)
2680 goto out_free_bitmap;
2681
2682 get_device(&gdev->dev);
2683 file->private_data = cdev;
2684
2685 ret = nonseekable_open(inode, file);
2686 if (ret)
2687 goto out_unregister_notifier;
2688
2689 up_read(&gdev->sem);
2690
2691 return ret;
2692
2693out_unregister_notifier:
2694 blocking_notifier_chain_unregister(&gdev->notifier,
2695 &cdev->lineinfo_changed_nb);
2696out_free_bitmap:
2697 bitmap_free(cdev->watched_lines);
2698out_free_cdev:
2699 kfree(cdev);
2700out_unlock:
2701 up_read(&gdev->sem);
2702 return ret;
2703}
2704
2705/**
2706 * gpio_chrdev_release() - close chardev after ioctl operations
2707 * @inode: inode for this chardev
2708 * @file: file struct for storing private data
2709 * Returns 0 on success
2710 */
2711static int gpio_chrdev_release(struct inode *inode, struct file *file)
2712{
2713 struct gpio_chardev_data *cdev = file->private_data;
2714 struct gpio_device *gdev = cdev->gdev;
2715
2716 bitmap_free(cdev->watched_lines);
2717 blocking_notifier_chain_unregister(&gdev->notifier,
2718 &cdev->lineinfo_changed_nb);
2719 put_device(&gdev->dev);
2720 kfree(cdev);
2721
2722 return 0;
2723}
2724
2725static const struct file_operations gpio_fileops = {
2726 .release = gpio_chrdev_release,
2727 .open = gpio_chrdev_open,
2728 .poll = lineinfo_watch_poll,
2729 .read = lineinfo_watch_read,
2730 .owner = THIS_MODULE,
2731 .llseek = no_llseek,
2732 .unlocked_ioctl = gpio_ioctl,
2733#ifdef CONFIG_COMPAT
2734 .compat_ioctl = gpio_ioctl_compat,
2735#endif
2736};
2737
2738int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
2739{
2740 int ret;
2741
2742 cdev_init(&gdev->chrdev, &gpio_fileops);
2743 gdev->chrdev.owner = THIS_MODULE;
2744 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
2745
2746 ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
2747 if (ret)
2748 return ret;
2749
2750 chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
2751 MAJOR(devt), gdev->id);
2752
2753 return 0;
2754}
2755
2756void gpiolib_cdev_unregister(struct gpio_device *gdev)
2757{
2758 cdev_device_del(&gdev->chrdev, &gdev->dev);
2759}