Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/anon_inodes.h>
4#include <linux/atomic.h>
5#include <linux/bitmap.h>
6#include <linux/build_bug.h>
7#include <linux/cdev.h>
8#include <linux/cleanup.h>
9#include <linux/compat.h>
10#include <linux/compiler.h>
11#include <linux/device.h>
12#include <linux/err.h>
13#include <linux/file.h>
14#include <linux/gpio.h>
15#include <linux/gpio/driver.h>
16#include <linux/hte.h>
17#include <linux/interrupt.h>
18#include <linux/irqreturn.h>
19#include <linux/kfifo.h>
20#include <linux/module.h>
21#include <linux/mutex.h>
22#include <linux/overflow.h>
23#include <linux/pinctrl/consumer.h>
24#include <linux/poll.h>
25#include <linux/seq_file.h>
26#include <linux/spinlock.h>
27#include <linux/string.h>
28#include <linux/timekeeping.h>
29#include <linux/uaccess.h>
30#include <linux/workqueue.h>
31
32#include <uapi/linux/gpio.h>
33
34#include "gpiolib.h"
35#include "gpiolib-cdev.h"
36
37/*
38 * Array sizes must ensure 64-bit alignment and not create holes in the
39 * struct packing.
40 */
41static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2));
42static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8));
43
44/*
45 * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility
46 */
47static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8));
48static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8));
49static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8));
50static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8));
51static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8));
52static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8));
53static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8));
54static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8));
55
56/* Character device interface to GPIO.
57 *
58 * The GPIO character device, /dev/gpiochipN, provides userspace an
59 * interface to gpiolib GPIOs via ioctl()s.
60 */
61
62/*
63 * GPIO line handle management
64 */
65
66#ifdef CONFIG_GPIO_CDEV_V1
67/**
68 * struct linehandle_state - contains the state of a userspace handle
69 * @gdev: the GPIO device the handle pertains to
70 * @label: consumer label used to tag descriptors
71 * @descs: the GPIO descriptors held by this handle
72 * @num_descs: the number of descriptors held in the descs array
73 */
74struct linehandle_state {
75 struct gpio_device *gdev;
76 const char *label;
77 struct gpio_desc *descs[GPIOHANDLES_MAX];
78 u32 num_descs;
79};
80
81#define GPIOHANDLE_REQUEST_VALID_FLAGS \
82 (GPIOHANDLE_REQUEST_INPUT | \
83 GPIOHANDLE_REQUEST_OUTPUT | \
84 GPIOHANDLE_REQUEST_ACTIVE_LOW | \
85 GPIOHANDLE_REQUEST_BIAS_PULL_UP | \
86 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \
87 GPIOHANDLE_REQUEST_BIAS_DISABLE | \
88 GPIOHANDLE_REQUEST_OPEN_DRAIN | \
89 GPIOHANDLE_REQUEST_OPEN_SOURCE)
90
91#define GPIOHANDLE_REQUEST_DIRECTION_FLAGS \
92 (GPIOHANDLE_REQUEST_INPUT | \
93 GPIOHANDLE_REQUEST_OUTPUT)
94
95static int linehandle_validate_flags(u32 flags)
96{
97 /* Return an error if an unknown flag is set */
98 if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
99 return -EINVAL;
100
101 /*
102 * Do not allow both INPUT & OUTPUT flags to be set as they are
103 * contradictory.
104 */
105 if ((flags & GPIOHANDLE_REQUEST_INPUT) &&
106 (flags & GPIOHANDLE_REQUEST_OUTPUT))
107 return -EINVAL;
108
109 /*
110 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
111 * the hardware actually supports enabling both at the same time the
112 * electrical result would be disastrous.
113 */
114 if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
115 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
116 return -EINVAL;
117
118 /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
119 if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) &&
120 ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
121 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
122 return -EINVAL;
123
124 /* Bias flags only allowed for input or output mode. */
125 if (!((flags & GPIOHANDLE_REQUEST_INPUT) ||
126 (flags & GPIOHANDLE_REQUEST_OUTPUT)) &&
127 ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) ||
128 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) ||
129 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
130 return -EINVAL;
131
132 /* Only one bias flag can be set. */
133 if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
134 (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
135 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
136 ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
137 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
138 return -EINVAL;
139
140 return 0;
141}
142
143static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp)
144{
145 unsigned long flags = READ_ONCE(*flagsp);
146
147 assign_bit(GPIOD_FLAG_ACTIVE_LOW, &flags,
148 lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
149 assign_bit(GPIOD_FLAG_OPEN_DRAIN, &flags,
150 lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
151 assign_bit(GPIOD_FLAG_OPEN_SOURCE, &flags,
152 lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
153 assign_bit(GPIOD_FLAG_PULL_UP, &flags,
154 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
155 assign_bit(GPIOD_FLAG_PULL_DOWN, &flags,
156 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
157 assign_bit(GPIOD_FLAG_BIAS_DISABLE, &flags,
158 lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
159
160 WRITE_ONCE(*flagsp, flags);
161}
162
163static long linehandle_set_config(struct linehandle_state *lh,
164 void __user *ip)
165{
166 struct gpiohandle_config gcnf;
167 struct gpio_desc *desc;
168 int i, ret;
169 u32 lflags;
170
171 if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
172 return -EFAULT;
173
174 lflags = gcnf.flags;
175 ret = linehandle_validate_flags(lflags);
176 if (ret)
177 return ret;
178
179 /* Lines must be reconfigured explicitly as input or output. */
180 if (!(lflags & GPIOHANDLE_REQUEST_DIRECTION_FLAGS))
181 return -EINVAL;
182
183 for (i = 0; i < lh->num_descs; i++) {
184 desc = lh->descs[i];
185 linehandle_flags_to_desc_flags(lflags, &desc->flags);
186
187 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
188 int val = !!gcnf.default_values[i];
189
190 ret = gpiod_direction_output_nonotify(desc, val);
191 if (ret)
192 return ret;
193 } else {
194 ret = gpiod_direction_input_nonotify(desc);
195 if (ret)
196 return ret;
197 }
198
199 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
200 }
201 return 0;
202}
203
204static long linehandle_ioctl(struct file *file, unsigned int cmd,
205 unsigned long arg)
206{
207 struct linehandle_state *lh = file->private_data;
208 void __user *ip = (void __user *)arg;
209 struct gpiohandle_data ghd;
210 DECLARE_BITMAP(vals, GPIOHANDLES_MAX);
211 unsigned int i;
212 int ret;
213
214 guard(srcu)(&lh->gdev->srcu);
215
216 if (!rcu_access_pointer(lh->gdev->chip))
217 return -ENODEV;
218
219 switch (cmd) {
220 case GPIOHANDLE_GET_LINE_VALUES_IOCTL:
221 /* NOTE: It's okay to read values of output lines */
222 ret = gpiod_get_array_value_complex(false, true,
223 lh->num_descs, lh->descs,
224 NULL, vals);
225 if (ret)
226 return ret;
227
228 memset(&ghd, 0, sizeof(ghd));
229 for (i = 0; i < lh->num_descs; i++)
230 ghd.values[i] = test_bit(i, vals);
231
232 if (copy_to_user(ip, &ghd, sizeof(ghd)))
233 return -EFAULT;
234
235 return 0;
236 case GPIOHANDLE_SET_LINE_VALUES_IOCTL:
237 /*
238 * All line descriptors were created at once with the same
239 * flags so just check if the first one is really output.
240 */
241 if (!test_bit(GPIOD_FLAG_IS_OUT, &lh->descs[0]->flags))
242 return -EPERM;
243
244 if (copy_from_user(&ghd, ip, sizeof(ghd)))
245 return -EFAULT;
246
247 /* Clamp all values to [0,1] */
248 for (i = 0; i < lh->num_descs; i++)
249 __assign_bit(i, vals, ghd.values[i]);
250
251 /* Reuse the array setting function */
252 return gpiod_set_array_value_complex(false,
253 true,
254 lh->num_descs,
255 lh->descs,
256 NULL,
257 vals);
258 case GPIOHANDLE_SET_CONFIG_IOCTL:
259 return linehandle_set_config(lh, ip);
260 default:
261 return -EINVAL;
262 }
263}
264
265#ifdef CONFIG_COMPAT
266static long linehandle_ioctl_compat(struct file *file, unsigned int cmd,
267 unsigned long arg)
268{
269 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
270}
271#endif
272
273static void linehandle_free(struct linehandle_state *lh)
274{
275 int i;
276
277 for (i = 0; i < lh->num_descs; i++)
278 if (lh->descs[i])
279 gpiod_free(lh->descs[i]);
280 kfree(lh->label);
281 gpio_device_put(lh->gdev);
282 kfree(lh);
283}
284
285static int linehandle_release(struct inode *inode, struct file *file)
286{
287 linehandle_free(file->private_data);
288 return 0;
289}
290
291static const struct file_operations linehandle_fileops = {
292 .release = linehandle_release,
293 .owner = THIS_MODULE,
294 .llseek = noop_llseek,
295 .unlocked_ioctl = linehandle_ioctl,
296#ifdef CONFIG_COMPAT
297 .compat_ioctl = linehandle_ioctl_compat,
298#endif
299};
300
301DEFINE_FREE(linehandle_free, struct linehandle_state *, if (!IS_ERR_OR_NULL(_T)) linehandle_free(_T))
302
303static int linehandle_create(struct gpio_device *gdev, void __user *ip)
304{
305 struct gpiohandle_request handlereq;
306 struct linehandle_state *lh __free(linehandle_free) = NULL;
307 int i, ret;
308 u32 lflags;
309
310 if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
311 return -EFAULT;
312 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
313 return -EINVAL;
314
315 lflags = handlereq.flags;
316
317 ret = linehandle_validate_flags(lflags);
318 if (ret)
319 return ret;
320
321 lh = kzalloc_obj(*lh);
322 if (!lh)
323 return -ENOMEM;
324 lh->gdev = gpio_device_get(gdev);
325
326 if (handlereq.consumer_label[0] != '\0') {
327 /* label is only initialized if consumer_label is set */
328 lh->label = kstrndup(handlereq.consumer_label,
329 sizeof(handlereq.consumer_label) - 1,
330 GFP_KERNEL);
331 if (!lh->label)
332 return -ENOMEM;
333 }
334
335 lh->num_descs = handlereq.lines;
336
337 /* Request each GPIO */
338 for (i = 0; i < handlereq.lines; i++) {
339 u32 offset = handlereq.lineoffsets[i];
340 struct gpio_desc *desc = gpio_device_get_desc(gdev, offset);
341
342 if (IS_ERR(desc))
343 return PTR_ERR(desc);
344
345 ret = gpiod_request_user(desc, lh->label);
346 if (ret)
347 return ret;
348 lh->descs[i] = desc;
349 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);
350
351 ret = gpiod_set_transitory(desc, false);
352 if (ret < 0)
353 return ret;
354
355 /*
356 * Lines have to be requested explicitly for input
357 * or output, else the line will be treated "as is".
358 */
359 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
360 int val = !!handlereq.default_values[i];
361
362 ret = gpiod_direction_output_nonotify(desc, val);
363 if (ret)
364 return ret;
365 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
366 ret = gpiod_direction_input_nonotify(desc);
367 if (ret)
368 return ret;
369 }
370
371 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
372
373 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
374 offset);
375 }
376
377 FD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,
378 anon_inode_getfile("gpio-linehandle", &linehandle_fileops,
379 lh, O_RDONLY | O_CLOEXEC));
380 if (fdf.err)
381 return fdf.err;
382 retain_and_null_ptr(lh);
383
384 handlereq.fd = fd_prepare_fd(fdf);
385 if (copy_to_user(ip, &handlereq, sizeof(handlereq)))
386 return -EFAULT;
387
388 fd_publish(fdf);
389
390 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
391 handlereq.lines);
392
393 return 0;
394}
395#endif /* CONFIG_GPIO_CDEV_V1 */
396
397/**
398 * struct line - contains the state of a requested line
399 * @desc: the GPIO descriptor for this line.
400 * @req: the corresponding line request
401 * @irq: the interrupt triggered in response to events on this GPIO
402 * @edflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or
403 * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied
404 * @timestamp_ns: cache for the timestamp storing it between hardirq and
405 * IRQ thread, used to bring the timestamp close to the actual event
406 * @req_seqno: the seqno for the current edge event in the sequence of
407 * events for the corresponding line request. This is drawn from the @req.
408 * @line_seqno: the seqno for the current edge event in the sequence of
409 * events for this line.
410 * @work: the worker that implements software debouncing
411 * @sw_debounced: flag indicating if the software debouncer is active
412 * @level: the current debounced physical level of the line
413 * @hdesc: the Hardware Timestamp Engine (HTE) descriptor
414 * @raw_level: the line level at the time of event
415 * @total_discard_seq: the running counter of the discarded events
416 * @last_seqno: the last sequence number before debounce period expires
417 */
418struct line {
419 struct gpio_desc *desc;
420 /*
421 * -- edge detector specific fields --
422 */
423 struct linereq *req;
424 unsigned int irq;
425 /*
426 * The flags for the active edge detector configuration.
427 *
428 * edflags is set by linereq_create(), linereq_free(), and
429 * linereq_set_config(), which are themselves mutually
430 * exclusive, and is accessed by edge_irq_thread(),
431 * process_hw_ts_thread() and debounce_work_func(),
432 * which can all live with a slightly stale value.
433 */
434 u64 edflags;
435 /*
436 * timestamp_ns and req_seqno are accessed only by
437 * edge_irq_handler() and edge_irq_thread(), which are themselves
438 * mutually exclusive, so no additional protection is necessary.
439 */
440 u64 timestamp_ns;
441 u32 req_seqno;
442 /*
443 * line_seqno is accessed by either edge_irq_thread() or
444 * debounce_work_func(), which are themselves mutually exclusive,
445 * so no additional protection is necessary.
446 */
447 u32 line_seqno;
448 /*
449 * -- debouncer specific fields --
450 */
451 struct delayed_work work;
452 /*
453 * sw_debounce is accessed by linereq_set_config(), which is the
454 * only setter, and linereq_get_values(), which can live with a
455 * slightly stale value.
456 */
457 unsigned int sw_debounced;
458 /*
459 * level is accessed by debounce_work_func(), which is the only
460 * setter, and linereq_get_values() which can live with a slightly
461 * stale value.
462 */
463 unsigned int level;
464#ifdef CONFIG_HTE
465 struct hte_ts_desc hdesc;
466 /*
467 * HTE provider sets line level at the time of event. The valid
468 * value is 0 or 1 and negative value for an error.
469 */
470 int raw_level;
471 /*
472 * when sw_debounce is set on HTE enabled line, this is running
473 * counter of the discarded events.
474 */
475 u32 total_discard_seq;
476 /*
477 * when sw_debounce is set on HTE enabled line, this variable records
478 * last sequence number before debounce period expires.
479 */
480 u32 last_seqno;
481#endif /* CONFIG_HTE */
482};
483
484/**
485 * struct linereq - contains the state of a userspace line request
486 * @gdev: the GPIO device the line request pertains to
487 * @label: consumer label used to tag GPIO descriptors
488 * @num_lines: the number of lines in the lines array
489 * @wait: wait queue that handles blocking reads of events
490 * @device_unregistered_nb: notifier block for receiving gdev unregister events
491 * @event_buffer_size: the number of elements allocated in @events
492 * @events: KFIFO for the GPIO events
493 * @seqno: the sequence number for edge events generated on all lines in
494 * this line request. Note that this is not used when @num_lines is 1, as
495 * the line_seqno is then the same and is cheaper to calculate.
496 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency
497 * of configuration, particularly multi-step accesses to desc flags.
498 * @lines: the lines held by this line request, with @num_lines elements.
499 */
500struct linereq {
501 struct gpio_device *gdev;
502 const char *label;
503 u32 num_lines;
504 wait_queue_head_t wait;
505 struct notifier_block device_unregistered_nb;
506 u32 event_buffer_size;
507 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
508 atomic_t seqno;
509 struct mutex config_mutex;
510 struct line lines[] __counted_by(num_lines);
511};
512
513#define GPIO_V2_LINE_BIAS_FLAGS \
514 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \
515 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \
516 GPIO_V2_LINE_FLAG_BIAS_DISABLED)
517
518#define GPIO_V2_LINE_DIRECTION_FLAGS \
519 (GPIO_V2_LINE_FLAG_INPUT | \
520 GPIO_V2_LINE_FLAG_OUTPUT)
521
522#define GPIO_V2_LINE_DRIVE_FLAGS \
523 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \
524 GPIO_V2_LINE_FLAG_OPEN_SOURCE)
525
526#define GPIO_V2_LINE_EDGE_FLAGS \
527 (GPIO_V2_LINE_FLAG_EDGE_RISING | \
528 GPIO_V2_LINE_FLAG_EDGE_FALLING)
529
530#define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS
531
532#define GPIO_V2_LINE_VALID_FLAGS \
533 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
534 GPIO_V2_LINE_DIRECTION_FLAGS | \
535 GPIO_V2_LINE_DRIVE_FLAGS | \
536 GPIO_V2_LINE_EDGE_FLAGS | \
537 GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \
538 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
539 GPIO_V2_LINE_BIAS_FLAGS)
540
541/* subset of flags relevant for edge detector configuration */
542#define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \
543 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
544 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
545 GPIO_V2_LINE_EDGE_FLAGS)
546
547static int linereq_unregistered_notify(struct notifier_block *nb,
548 unsigned long action, void *data)
549{
550 struct linereq *lr = container_of(nb, struct linereq,
551 device_unregistered_nb);
552
553 wake_up_poll(&lr->wait, EPOLLIN | EPOLLERR);
554
555 return NOTIFY_OK;
556}
557
558static void linereq_put_event(struct linereq *lr,
559 struct gpio_v2_line_event *le)
560{
561 bool overflow = false;
562
563 scoped_guard(spinlock, &lr->wait.lock) {
564 if (kfifo_is_full(&lr->events)) {
565 overflow = true;
566 kfifo_skip(&lr->events);
567 }
568 kfifo_in(&lr->events, le, 1);
569 }
570 if (!overflow)
571 wake_up_poll(&lr->wait, EPOLLIN);
572 else
573 pr_debug_ratelimited("event FIFO is full - event dropped\n");
574}
575
576static u64 line_event_timestamp(struct line *line)
577{
578 if (test_bit(GPIOD_FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags))
579 return ktime_get_real_ns();
580 else if (IS_ENABLED(CONFIG_HTE) &&
581 test_bit(GPIOD_FLAG_EVENT_CLOCK_HTE, &line->desc->flags))
582 return line->timestamp_ns;
583
584 return ktime_get_ns();
585}
586
587static u32 line_event_id(int level)
588{
589 return level ? GPIO_V2_LINE_EVENT_RISING_EDGE :
590 GPIO_V2_LINE_EVENT_FALLING_EDGE;
591}
592
593static inline char *make_irq_label(const char *orig)
594{
595 char *new;
596
597 if (!orig)
598 return NULL;
599
600 new = kstrdup_and_replace(orig, '/', ':', GFP_KERNEL);
601 if (!new)
602 return ERR_PTR(-ENOMEM);
603
604 return new;
605}
606
607static inline void free_irq_label(const char *label)
608{
609 kfree(label);
610}
611
612#ifdef CONFIG_HTE
613
614static enum hte_return process_hw_ts_thread(void *p)
615{
616 struct line *line;
617 struct linereq *lr;
618 struct gpio_v2_line_event le;
619 u64 edflags;
620 int level;
621
622 if (!p)
623 return HTE_CB_HANDLED;
624
625 line = p;
626 lr = line->req;
627
628 memset(&le, 0, sizeof(le));
629
630 le.timestamp_ns = line->timestamp_ns;
631 edflags = READ_ONCE(line->edflags);
632
633 switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) {
634 case GPIO_V2_LINE_FLAG_EDGE_BOTH:
635 level = (line->raw_level >= 0) ?
636 line->raw_level :
637 gpiod_get_raw_value_cansleep(line->desc);
638
639 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
640 level = !level;
641
642 le.id = line_event_id(level);
643 break;
644 case GPIO_V2_LINE_FLAG_EDGE_RISING:
645 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
646 break;
647 case GPIO_V2_LINE_FLAG_EDGE_FALLING:
648 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
649 break;
650 default:
651 return HTE_CB_HANDLED;
652 }
653 le.line_seqno = line->line_seqno;
654 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
655 le.offset = gpiod_hwgpio(line->desc);
656
657 linereq_put_event(lr, &le);
658
659 return HTE_CB_HANDLED;
660}
661
662static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p)
663{
664 struct line *line;
665 struct linereq *lr;
666 int diff_seqno = 0;
667
668 if (!ts || !p)
669 return HTE_CB_HANDLED;
670
671 line = p;
672 line->timestamp_ns = ts->tsc;
673 line->raw_level = ts->raw_level;
674 lr = line->req;
675
676 if (READ_ONCE(line->sw_debounced)) {
677 line->total_discard_seq++;
678 line->last_seqno = ts->seq;
679 mod_delayed_work(system_percpu_wq, &line->work,
680 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
681 } else {
682 if (unlikely(ts->seq < line->line_seqno))
683 return HTE_CB_HANDLED;
684
685 diff_seqno = ts->seq - line->line_seqno;
686 line->line_seqno = ts->seq;
687 if (lr->num_lines != 1)
688 line->req_seqno = atomic_add_return(diff_seqno,
689 &lr->seqno);
690
691 return HTE_RUN_SECOND_CB;
692 }
693
694 return HTE_CB_HANDLED;
695}
696
697static int hte_edge_setup(struct line *line, u64 eflags)
698{
699 int ret;
700 unsigned long flags = 0;
701 struct hte_ts_desc *hdesc = &line->hdesc;
702
703 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
704 flags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &line->desc->flags) ?
705 HTE_FALLING_EDGE_TS :
706 HTE_RISING_EDGE_TS;
707 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
708 flags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &line->desc->flags) ?
709 HTE_RISING_EDGE_TS :
710 HTE_FALLING_EDGE_TS;
711
712 line->total_discard_seq = 0;
713
714 hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL,
715 line->desc);
716
717 ret = hte_ts_get(NULL, hdesc, 0);
718 if (ret)
719 return ret;
720
721 return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread,
722 line);
723}
724
725#else
726
727static int hte_edge_setup(struct line *line, u64 eflags)
728{
729 return 0;
730}
731#endif /* CONFIG_HTE */
732
733static irqreturn_t edge_irq_thread(int irq, void *p)
734{
735 struct line *line = p;
736 struct linereq *lr = line->req;
737 struct gpio_v2_line_event le;
738
739 /* Do not leak kernel stack to userspace */
740 memset(&le, 0, sizeof(le));
741
742 if (line->timestamp_ns) {
743 le.timestamp_ns = line->timestamp_ns;
744 } else {
745 /*
746 * We may be running from a nested threaded interrupt in
747 * which case we didn't get the timestamp from
748 * edge_irq_handler().
749 */
750 le.timestamp_ns = line_event_timestamp(line);
751 if (lr->num_lines != 1)
752 line->req_seqno = atomic_inc_return(&lr->seqno);
753 }
754 line->timestamp_ns = 0;
755
756 switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) {
757 case GPIO_V2_LINE_FLAG_EDGE_BOTH:
758 le.id = line_event_id(gpiod_get_value_cansleep(line->desc));
759 break;
760 case GPIO_V2_LINE_FLAG_EDGE_RISING:
761 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
762 break;
763 case GPIO_V2_LINE_FLAG_EDGE_FALLING:
764 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
765 break;
766 default:
767 return IRQ_NONE;
768 }
769 line->line_seqno++;
770 le.line_seqno = line->line_seqno;
771 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
772 le.offset = gpiod_hwgpio(line->desc);
773
774 linereq_put_event(lr, &le);
775
776 return IRQ_HANDLED;
777}
778
779static irqreturn_t edge_irq_handler(int irq, void *p)
780{
781 struct line *line = p;
782 struct linereq *lr = line->req;
783
784 /*
785 * Just store the timestamp in hardirq context so we get it as
786 * close in time as possible to the actual event.
787 */
788 line->timestamp_ns = line_event_timestamp(line);
789
790 if (lr->num_lines != 1)
791 line->req_seqno = atomic_inc_return(&lr->seqno);
792
793 return IRQ_WAKE_THREAD;
794}
795
796/*
797 * returns the current debounced logical value.
798 */
799static bool debounced_value(struct line *line)
800{
801 bool value;
802
803 /*
804 * minor race - debouncer may be stopped here, so edge_detector_stop()
805 * must leave the value unchanged so the following will read the level
806 * from when the debouncer was last running.
807 */
808 value = READ_ONCE(line->level);
809
810 if (test_bit(GPIOD_FLAG_ACTIVE_LOW, &line->desc->flags))
811 value = !value;
812
813 return value;
814}
815
816static irqreturn_t debounce_irq_handler(int irq, void *p)
817{
818 struct line *line = p;
819
820 mod_delayed_work(system_percpu_wq, &line->work,
821 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
822
823 return IRQ_HANDLED;
824}
825
826static void debounce_work_func(struct work_struct *work)
827{
828 struct gpio_v2_line_event le;
829 struct line *line = container_of(work, struct line, work.work);
830 struct linereq *lr;
831 u64 eflags, edflags = READ_ONCE(line->edflags);
832 int level = -1;
833#ifdef CONFIG_HTE
834 int diff_seqno;
835
836 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
837 level = line->raw_level;
838#endif
839 if (level < 0)
840 level = gpiod_get_raw_value_cansleep(line->desc);
841 if (level < 0) {
842 pr_debug_ratelimited("debouncer failed to read line value\n");
843 return;
844 }
845
846 if (READ_ONCE(line->level) == level)
847 return;
848
849 WRITE_ONCE(line->level, level);
850
851 /* -- edge detection -- */
852 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
853 if (!eflags)
854 return;
855
856 /* switch from physical level to logical - if they differ */
857 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
858 level = !level;
859
860 /* ignore edges that are not being monitored */
861 if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) ||
862 ((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level))
863 return;
864
865 /* Do not leak kernel stack to userspace */
866 memset(&le, 0, sizeof(le));
867
868 lr = line->req;
869 le.timestamp_ns = line_event_timestamp(line);
870 le.offset = gpiod_hwgpio(line->desc);
871#ifdef CONFIG_HTE
872 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) {
873 /* discard events except the last one */
874 line->total_discard_seq -= 1;
875 diff_seqno = line->last_seqno - line->total_discard_seq -
876 line->line_seqno;
877 line->line_seqno = line->last_seqno - line->total_discard_seq;
878 le.line_seqno = line->line_seqno;
879 le.seqno = (lr->num_lines == 1) ?
880 le.line_seqno : atomic_add_return(diff_seqno, &lr->seqno);
881 } else
882#endif /* CONFIG_HTE */
883 {
884 line->line_seqno++;
885 le.line_seqno = line->line_seqno;
886 le.seqno = (lr->num_lines == 1) ?
887 le.line_seqno : atomic_inc_return(&lr->seqno);
888 }
889
890 le.id = line_event_id(level);
891
892 linereq_put_event(lr, &le);
893}
894
895static int debounce_setup(struct line *line, unsigned int debounce_period_us)
896{
897 unsigned long irqflags;
898 int ret, level, irq;
899 char *label;
900
901 /*
902 * Try hardware. Skip gpiod_set_config() to avoid emitting two
903 * CHANGED_CONFIG line state events.
904 */
905 ret = gpio_do_set_config(line->desc,
906 pinconf_to_config_packed(PIN_CONFIG_INPUT_DEBOUNCE,
907 debounce_period_us));
908 if (ret != -ENOTSUPP)
909 return ret;
910
911 if (debounce_period_us) {
912 /* setup software debounce */
913 level = gpiod_get_raw_value_cansleep(line->desc);
914 if (level < 0)
915 return level;
916
917 if (!(IS_ENABLED(CONFIG_HTE) &&
918 test_bit(GPIOD_FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) {
919 irq = gpiod_to_irq(line->desc);
920 if (irq < 0)
921 return -ENXIO;
922
923 label = make_irq_label(line->req->label);
924 if (IS_ERR(label))
925 return -ENOMEM;
926
927 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
928 ret = request_irq(irq, debounce_irq_handler, irqflags,
929 label, line);
930 if (ret) {
931 free_irq_label(label);
932 return ret;
933 }
934 line->irq = irq;
935 } else {
936 ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH);
937 if (ret)
938 return ret;
939 }
940
941 WRITE_ONCE(line->level, level);
942 WRITE_ONCE(line->sw_debounced, 1);
943 }
944 return 0;
945}
946
947static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc,
948 unsigned int line_idx)
949{
950 unsigned int i;
951 u64 mask = BIT_ULL(line_idx);
952
953 for (i = 0; i < lc->num_attrs; i++) {
954 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
955 (lc->attrs[i].mask & mask))
956 return true;
957 }
958 return false;
959}
960
961static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
962 unsigned int line_idx)
963{
964 unsigned int i;
965 u64 mask = BIT_ULL(line_idx);
966
967 for (i = 0; i < lc->num_attrs; i++) {
968 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
969 (lc->attrs[i].mask & mask))
970 return lc->attrs[i].attr.debounce_period_us;
971 }
972 return 0;
973}
974
975static void edge_detector_stop(struct line *line)
976{
977 if (line->irq) {
978 free_irq_label(free_irq(line->irq, line));
979 line->irq = 0;
980 }
981
982#ifdef CONFIG_HTE
983 if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
984 hte_ts_put(&line->hdesc);
985#endif
986
987 cancel_delayed_work_sync(&line->work);
988 WRITE_ONCE(line->sw_debounced, 0);
989 WRITE_ONCE(line->edflags, 0);
990 if (line->desc)
991 WRITE_ONCE(line->desc->debounce_period_us, 0);
992 /* do not change line->level - see comment in debounced_value() */
993}
994
995static int edge_detector_fifo_init(struct linereq *req)
996{
997 if (kfifo_initialized(&req->events))
998 return 0;
999
1000 return kfifo_alloc(&req->events, req->event_buffer_size, GFP_KERNEL);
1001}
1002
1003static int edge_detector_setup(struct line *line,
1004 struct gpio_v2_line_config *lc,
1005 unsigned int line_idx, u64 edflags)
1006{
1007 u32 debounce_period_us;
1008 unsigned long irqflags = 0;
1009 u64 eflags;
1010 int irq, ret;
1011 char *label;
1012
1013 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
1014 if (eflags) {
1015 ret = edge_detector_fifo_init(line->req);
1016 if (ret)
1017 return ret;
1018 }
1019 if (gpio_v2_line_config_debounced(lc, line_idx)) {
1020 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
1021 ret = debounce_setup(line, debounce_period_us);
1022 if (ret)
1023 return ret;
1024 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
1025 }
1026
1027 /* detection disabled or sw debouncer will provide edge detection */
1028 if (!eflags || READ_ONCE(line->sw_debounced))
1029 return 0;
1030
1031 if (IS_ENABLED(CONFIG_HTE) &&
1032 (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1033 return hte_edge_setup(line, edflags);
1034
1035 irq = gpiod_to_irq(line->desc);
1036 if (irq < 0)
1037 return -ENXIO;
1038
1039 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
1040 irqflags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &line->desc->flags) ?
1041 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
1042 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
1043 irqflags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &line->desc->flags) ?
1044 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
1045 irqflags |= IRQF_ONESHOT;
1046
1047 label = make_irq_label(line->req->label);
1048 if (IS_ERR(label))
1049 return PTR_ERR(label);
1050
1051 /* Request a thread to read the events */
1052 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
1053 irqflags, label, line);
1054 if (ret) {
1055 free_irq_label(label);
1056 return ret;
1057 }
1058
1059 line->irq = irq;
1060 return 0;
1061}
1062
1063static int edge_detector_update(struct line *line,
1064 struct gpio_v2_line_config *lc,
1065 unsigned int line_idx, u64 edflags)
1066{
1067 u64 active_edflags = READ_ONCE(line->edflags);
1068 unsigned int debounce_period_us =
1069 gpio_v2_line_config_debounce_period(lc, line_idx);
1070
1071 if ((active_edflags == edflags) &&
1072 (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us))
1073 return 0;
1074
1075 /* sw debounced and still will be...*/
1076 if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
1077 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
1078 /*
1079 * ensure event fifo is initialised if edge detection
1080 * is now enabled.
1081 */
1082 if (edflags & GPIO_V2_LINE_EDGE_FLAGS)
1083 return edge_detector_fifo_init(line->req);
1084
1085 return 0;
1086 }
1087
1088 /* reconfiguring edge detection or sw debounce being disabled */
1089 if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
1090 (active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) ||
1091 (!debounce_period_us && READ_ONCE(line->sw_debounced)))
1092 edge_detector_stop(line);
1093
1094 return edge_detector_setup(line, lc, line_idx, edflags);
1095}
1096
1097static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
1098 unsigned int line_idx)
1099{
1100 unsigned int i;
1101 u64 mask = BIT_ULL(line_idx);
1102
1103 for (i = 0; i < lc->num_attrs; i++) {
1104 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) &&
1105 (lc->attrs[i].mask & mask))
1106 return lc->attrs[i].attr.flags;
1107 }
1108 return lc->flags;
1109}
1110
1111static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc,
1112 unsigned int line_idx)
1113{
1114 unsigned int i;
1115 u64 mask = BIT_ULL(line_idx);
1116
1117 for (i = 0; i < lc->num_attrs; i++) {
1118 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) &&
1119 (lc->attrs[i].mask & mask))
1120 return !!(lc->attrs[i].attr.values & mask);
1121 }
1122 return 0;
1123}
1124
1125static int gpio_v2_line_flags_validate(u64 flags)
1126{
1127 /* Return an error if an unknown flag is set */
1128 if (flags & ~GPIO_V2_LINE_VALID_FLAGS)
1129 return -EINVAL;
1130
1131 if (!IS_ENABLED(CONFIG_HTE) &&
1132 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1133 return -EOPNOTSUPP;
1134
1135 /*
1136 * Do not allow both INPUT and OUTPUT flags to be set as they are
1137 * contradictory.
1138 */
1139 if ((flags & GPIO_V2_LINE_FLAG_INPUT) &&
1140 (flags & GPIO_V2_LINE_FLAG_OUTPUT))
1141 return -EINVAL;
1142
1143 /* Only allow one event clock source */
1144 if (IS_ENABLED(CONFIG_HTE) &&
1145 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME) &&
1146 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1147 return -EINVAL;
1148
1149 /* Edge detection requires explicit input. */
1150 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) &&
1151 !(flags & GPIO_V2_LINE_FLAG_INPUT))
1152 return -EINVAL;
1153
1154 /*
1155 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single
1156 * request. If the hardware actually supports enabling both at the
1157 * same time the electrical result would be disastrous.
1158 */
1159 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) &&
1160 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE))
1161 return -EINVAL;
1162
1163 /* Drive requires explicit output direction. */
1164 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) &&
1165 !(flags & GPIO_V2_LINE_FLAG_OUTPUT))
1166 return -EINVAL;
1167
1168 /* Bias requires explicit direction. */
1169 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) &&
1170 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
1171 return -EINVAL;
1172
1173 /* Only one bias flag can be set. */
1174 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) &&
1175 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN |
1176 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) ||
1177 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) &&
1178 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)))
1179 return -EINVAL;
1180
1181 return 0;
1182}
1183
1184static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
1185 unsigned int num_lines)
1186{
1187 unsigned int i;
1188 u64 flags;
1189 int ret;
1190
1191 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX)
1192 return -EINVAL;
1193
1194 if (!mem_is_zero(lc->padding, sizeof(lc->padding)))
1195 return -EINVAL;
1196
1197 for (i = 0; i < num_lines; i++) {
1198 flags = gpio_v2_line_config_flags(lc, i);
1199 ret = gpio_v2_line_flags_validate(flags);
1200 if (ret)
1201 return ret;
1202
1203 /* debounce requires explicit input */
1204 if (gpio_v2_line_config_debounced(lc, i) &&
1205 !(flags & GPIO_V2_LINE_FLAG_INPUT))
1206 return -EINVAL;
1207 }
1208 return 0;
1209}
1210
1211static void gpio_v2_line_config_flags_to_desc_flags(u64 lflags,
1212 unsigned long *flagsp)
1213{
1214 unsigned long flags = READ_ONCE(*flagsp);
1215
1216 assign_bit(GPIOD_FLAG_ACTIVE_LOW, &flags,
1217 lflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW);
1218
1219 if (lflags & GPIO_V2_LINE_FLAG_OUTPUT)
1220 set_bit(GPIOD_FLAG_IS_OUT, &flags);
1221 else if (lflags & GPIO_V2_LINE_FLAG_INPUT)
1222 clear_bit(GPIOD_FLAG_IS_OUT, &flags);
1223
1224 assign_bit(GPIOD_FLAG_EDGE_RISING, &flags,
1225 lflags & GPIO_V2_LINE_FLAG_EDGE_RISING);
1226 assign_bit(GPIOD_FLAG_EDGE_FALLING, &flags,
1227 lflags & GPIO_V2_LINE_FLAG_EDGE_FALLING);
1228
1229 assign_bit(GPIOD_FLAG_OPEN_DRAIN, &flags,
1230 lflags & GPIO_V2_LINE_FLAG_OPEN_DRAIN);
1231 assign_bit(GPIOD_FLAG_OPEN_SOURCE, &flags,
1232 lflags & GPIO_V2_LINE_FLAG_OPEN_SOURCE);
1233
1234 assign_bit(GPIOD_FLAG_PULL_UP, &flags,
1235 lflags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP);
1236 assign_bit(GPIOD_FLAG_PULL_DOWN, &flags,
1237 lflags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN);
1238 assign_bit(GPIOD_FLAG_BIAS_DISABLE, &flags,
1239 lflags & GPIO_V2_LINE_FLAG_BIAS_DISABLED);
1240
1241 assign_bit(GPIOD_FLAG_EVENT_CLOCK_REALTIME, &flags,
1242 lflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME);
1243 assign_bit(GPIOD_FLAG_EVENT_CLOCK_HTE, &flags,
1244 lflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE);
1245
1246 WRITE_ONCE(*flagsp, flags);
1247}
1248
1249static long linereq_get_values(struct linereq *lr, void __user *ip)
1250{
1251 struct gpio_v2_line_values lv;
1252 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1253 struct gpio_desc **descs;
1254 unsigned int i, didx, num_get;
1255 bool val;
1256 int ret;
1257
1258 /* NOTE: It's ok to read values of output lines. */
1259 if (copy_from_user(&lv, ip, sizeof(lv)))
1260 return -EFAULT;
1261
1262 /*
1263 * gpiod_get_array_value_complex() requires compacted desc and val
1264 * arrays, rather than the sparse ones in lv.
1265 * Calculation of num_get and construction of the desc array is
1266 * optimized to avoid allocation for the desc array for the common
1267 * num_get == 1 case.
1268 */
1269 /* scan requested lines to calculate the subset to get */
1270 for (num_get = 0, i = 0; i < lr->num_lines; i++) {
1271 if (lv.mask & BIT_ULL(i)) {
1272 num_get++;
1273 /* capture desc for the num_get == 1 case */
1274 descs = &lr->lines[i].desc;
1275 }
1276 }
1277
1278 if (num_get == 0)
1279 return -EINVAL;
1280
1281 if (num_get != 1) {
1282 /* build compacted desc array */
1283 descs = kmalloc_objs(*descs, num_get);
1284 if (!descs)
1285 return -ENOMEM;
1286 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1287 if (lv.mask & BIT_ULL(i)) {
1288 descs[didx] = lr->lines[i].desc;
1289 didx++;
1290 }
1291 }
1292 }
1293 ret = gpiod_get_array_value_complex(false, true, num_get,
1294 descs, NULL, vals);
1295
1296 if (num_get != 1)
1297 kfree(descs);
1298 if (ret)
1299 return ret;
1300
1301 lv.bits = 0;
1302 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1303 /* unpack compacted vals for the response */
1304 if (lv.mask & BIT_ULL(i)) {
1305 if (lr->lines[i].sw_debounced)
1306 val = debounced_value(&lr->lines[i]);
1307 else
1308 val = test_bit(didx, vals);
1309 if (val)
1310 lv.bits |= BIT_ULL(i);
1311 didx++;
1312 }
1313 }
1314
1315 if (copy_to_user(ip, &lv, sizeof(lv)))
1316 return -EFAULT;
1317
1318 return 0;
1319}
1320
1321static long linereq_set_values(struct linereq *lr, void __user *ip)
1322{
1323 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1324 struct gpio_v2_line_values lv;
1325 struct gpio_desc **descs;
1326 unsigned int i, didx, num_set;
1327 int ret;
1328
1329 if (copy_from_user(&lv, ip, sizeof(lv)))
1330 return -EFAULT;
1331
1332 guard(mutex)(&lr->config_mutex);
1333
1334 /*
1335 * gpiod_set_array_value_complex() requires compacted desc and val
1336 * arrays, rather than the sparse ones in lv.
1337 * Calculation of num_set and construction of the descs and vals arrays
1338 * is optimized to minimize scanning the lv->mask, and to avoid
1339 * allocation for the desc array for the common num_set == 1 case.
1340 */
1341 bitmap_zero(vals, GPIO_V2_LINES_MAX);
1342 /* scan requested lines to determine the subset to be set */
1343 for (num_set = 0, i = 0; i < lr->num_lines; i++) {
1344 if (lv.mask & BIT_ULL(i)) {
1345 /* add to compacted values */
1346 if (lv.bits & BIT_ULL(i))
1347 __set_bit(num_set, vals);
1348 num_set++;
1349 /* capture desc for the num_set == 1 case */
1350 descs = &lr->lines[i].desc;
1351 }
1352 }
1353 if (num_set == 0)
1354 return -EINVAL;
1355
1356 if (num_set != 1) {
1357 /* build compacted desc array */
1358 descs = kmalloc_objs(*descs, num_set);
1359 if (!descs)
1360 return -ENOMEM;
1361 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1362 if (lv.mask & BIT_ULL(i)) {
1363 descs[didx] = lr->lines[i].desc;
1364 didx++;
1365 }
1366 }
1367 }
1368 ret = gpiod_set_array_value_complex(false, true, num_set,
1369 descs, NULL, vals);
1370
1371 if (num_set != 1)
1372 kfree(descs);
1373 return ret;
1374}
1375
1376static long linereq_set_config(struct linereq *lr, void __user *ip)
1377{
1378 struct gpio_v2_line_config lc;
1379 struct gpio_desc *desc;
1380 struct line *line;
1381 unsigned int i;
1382 u64 flags, edflags;
1383 int ret;
1384
1385 if (copy_from_user(&lc, ip, sizeof(lc)))
1386 return -EFAULT;
1387
1388 ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
1389 if (ret)
1390 return ret;
1391
1392 guard(mutex)(&lr->config_mutex);
1393
1394 for (i = 0; i < lr->num_lines; i++) {
1395 line = &lr->lines[i];
1396 desc = lr->lines[i].desc;
1397 flags = gpio_v2_line_config_flags(&lc, i);
1398 /*
1399 * Lines not explicitly reconfigured as input or output
1400 * are left unchanged.
1401 */
1402 if (!(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
1403 continue;
1404 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1405 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
1406 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1407 int val = gpio_v2_line_config_output_value(&lc, i);
1408
1409 edge_detector_stop(line);
1410 ret = gpiod_direction_output_nonotify(desc, val);
1411 if (ret)
1412 return ret;
1413 } else {
1414 ret = gpiod_direction_input_nonotify(desc);
1415 if (ret)
1416 return ret;
1417
1418 ret = edge_detector_update(line, &lc, i, edflags);
1419 if (ret)
1420 return ret;
1421 }
1422
1423 WRITE_ONCE(line->edflags, edflags);
1424
1425 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
1426 }
1427 return 0;
1428}
1429
1430static long linereq_ioctl(struct file *file, unsigned int cmd,
1431 unsigned long arg)
1432{
1433 struct linereq *lr = file->private_data;
1434 void __user *ip = (void __user *)arg;
1435
1436 guard(srcu)(&lr->gdev->srcu);
1437
1438 if (!rcu_access_pointer(lr->gdev->chip))
1439 return -ENODEV;
1440
1441 switch (cmd) {
1442 case GPIO_V2_LINE_GET_VALUES_IOCTL:
1443 return linereq_get_values(lr, ip);
1444 case GPIO_V2_LINE_SET_VALUES_IOCTL:
1445 return linereq_set_values(lr, ip);
1446 case GPIO_V2_LINE_SET_CONFIG_IOCTL:
1447 return linereq_set_config(lr, ip);
1448 default:
1449 return -EINVAL;
1450 }
1451}
1452
1453#ifdef CONFIG_COMPAT
1454static long linereq_ioctl_compat(struct file *file, unsigned int cmd,
1455 unsigned long arg)
1456{
1457 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1458}
1459#endif
1460
1461static __poll_t linereq_poll(struct file *file,
1462 struct poll_table_struct *wait)
1463{
1464 struct linereq *lr = file->private_data;
1465 __poll_t events = 0;
1466
1467 guard(srcu)(&lr->gdev->srcu);
1468
1469 if (!rcu_access_pointer(lr->gdev->chip))
1470 return EPOLLHUP | EPOLLERR;
1471
1472 poll_wait(file, &lr->wait, wait);
1473
1474 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events,
1475 &lr->wait.lock))
1476 events = EPOLLIN | EPOLLRDNORM;
1477
1478 return events;
1479}
1480
1481static ssize_t linereq_read(struct file *file, char __user *buf,
1482 size_t count, loff_t *f_ps)
1483{
1484 struct linereq *lr = file->private_data;
1485 struct gpio_v2_line_event le;
1486 ssize_t bytes_read = 0;
1487 int ret;
1488
1489 guard(srcu)(&lr->gdev->srcu);
1490
1491 if (!rcu_access_pointer(lr->gdev->chip))
1492 return -ENODEV;
1493
1494 if (count < sizeof(le))
1495 return -EINVAL;
1496
1497 do {
1498 scoped_guard(spinlock, &lr->wait.lock) {
1499 if (kfifo_is_empty(&lr->events)) {
1500 if (bytes_read)
1501 return bytes_read;
1502
1503 if (file->f_flags & O_NONBLOCK)
1504 return -EAGAIN;
1505
1506 ret = wait_event_interruptible_locked(lr->wait,
1507 !kfifo_is_empty(&lr->events));
1508 if (ret)
1509 return ret;
1510 }
1511
1512 if (kfifo_out(&lr->events, &le, 1) != 1) {
1513 /*
1514 * This should never happen - we hold the
1515 * lock from the moment we learned the fifo
1516 * is no longer empty until now.
1517 */
1518 WARN(1, "failed to read from non-empty kfifo");
1519 return -EIO;
1520 }
1521 }
1522
1523 if (copy_to_user(buf + bytes_read, &le, sizeof(le)))
1524 return -EFAULT;
1525 bytes_read += sizeof(le);
1526 } while (count >= bytes_read + sizeof(le));
1527
1528 return bytes_read;
1529}
1530
1531static void linereq_free(struct linereq *lr)
1532{
1533 unsigned int i;
1534
1535 if (lr->device_unregistered_nb.notifier_call)
1536 blocking_notifier_chain_unregister(&lr->gdev->device_notifier,
1537 &lr->device_unregistered_nb);
1538
1539 for (i = 0; i < lr->num_lines; i++) {
1540 if (lr->lines[i].desc) {
1541 edge_detector_stop(&lr->lines[i]);
1542 gpiod_free(lr->lines[i].desc);
1543 }
1544 }
1545 kfifo_free(&lr->events);
1546 kfree(lr->label);
1547 gpio_device_put(lr->gdev);
1548 kvfree(lr);
1549}
1550
1551static int linereq_release(struct inode *inode, struct file *file)
1552{
1553 struct linereq *lr = file->private_data;
1554
1555 linereq_free(lr);
1556 return 0;
1557}
1558
1559#ifdef CONFIG_PROC_FS
1560static void linereq_show_fdinfo(struct seq_file *out, struct file *file)
1561{
1562 struct linereq *lr = file->private_data;
1563 struct device *dev = &lr->gdev->dev;
1564 u16 i;
1565
1566 seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev));
1567
1568 for (i = 0; i < lr->num_lines; i++)
1569 seq_printf(out, "gpio-line:\t%d\n",
1570 gpiod_hwgpio(lr->lines[i].desc));
1571}
1572#endif
1573
1574static const struct file_operations line_fileops = {
1575 .release = linereq_release,
1576 .read = linereq_read,
1577 .poll = linereq_poll,
1578 .owner = THIS_MODULE,
1579 .llseek = noop_llseek,
1580 .unlocked_ioctl = linereq_ioctl,
1581#ifdef CONFIG_COMPAT
1582 .compat_ioctl = linereq_ioctl_compat,
1583#endif
1584#ifdef CONFIG_PROC_FS
1585 .show_fdinfo = linereq_show_fdinfo,
1586#endif
1587};
1588
1589DEFINE_FREE(linereq_free, struct linereq *, if (!IS_ERR_OR_NULL(_T)) linereq_free(_T))
1590
1591static int linereq_create(struct gpio_device *gdev, void __user *ip)
1592{
1593 struct gpio_v2_line_request ulr;
1594 struct gpio_v2_line_config *lc;
1595 struct linereq *lr __free(linereq_free) = NULL;
1596 u64 flags, edflags;
1597 unsigned int i;
1598 int ret;
1599
1600 if (copy_from_user(&ulr, ip, sizeof(ulr)))
1601 return -EFAULT;
1602
1603 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
1604 return -EINVAL;
1605
1606 if (!mem_is_zero(ulr.padding, sizeof(ulr.padding)))
1607 return -EINVAL;
1608
1609 lc = &ulr.config;
1610 ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
1611 if (ret)
1612 return ret;
1613
1614 lr = kvzalloc_flex(*lr, lines, ulr.num_lines);
1615 if (!lr)
1616 return -ENOMEM;
1617 lr->num_lines = ulr.num_lines;
1618
1619 lr->gdev = gpio_device_get(gdev);
1620
1621 for (i = 0; i < ulr.num_lines; i++) {
1622 lr->lines[i].req = lr;
1623 WRITE_ONCE(lr->lines[i].sw_debounced, 0);
1624 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
1625 }
1626
1627 if (ulr.consumer[0] != '\0') {
1628 /* label is only initialized if consumer is set */
1629 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
1630 GFP_KERNEL);
1631 if (!lr->label)
1632 return -ENOMEM;
1633 }
1634
1635 mutex_init(&lr->config_mutex);
1636 init_waitqueue_head(&lr->wait);
1637 INIT_KFIFO(lr->events);
1638 lr->event_buffer_size = ulr.event_buffer_size;
1639 if (lr->event_buffer_size == 0)
1640 lr->event_buffer_size = ulr.num_lines * 16;
1641 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16)
1642 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;
1643
1644 atomic_set(&lr->seqno, 0);
1645
1646 /* Request each GPIO */
1647 for (i = 0; i < ulr.num_lines; i++) {
1648 u32 offset = ulr.offsets[i];
1649 struct gpio_desc *desc = gpio_device_get_desc(gdev, offset);
1650
1651 if (IS_ERR(desc))
1652 return PTR_ERR(desc);
1653
1654 ret = gpiod_request_user(desc, lr->label);
1655 if (ret)
1656 return ret;
1657
1658 lr->lines[i].desc = desc;
1659 flags = gpio_v2_line_config_flags(lc, i);
1660 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1661
1662 ret = gpiod_set_transitory(desc, false);
1663 if (ret < 0)
1664 return ret;
1665
1666 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
1667 /*
1668 * Lines have to be requested explicitly for input
1669 * or output, else the line will be treated "as is".
1670 */
1671 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1672 int val = gpio_v2_line_config_output_value(lc, i);
1673
1674 ret = gpiod_direction_output_nonotify(desc, val);
1675 if (ret)
1676 return ret;
1677 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1678 ret = gpiod_direction_input_nonotify(desc);
1679 if (ret)
1680 return ret;
1681
1682 ret = edge_detector_setup(&lr->lines[i], lc, i,
1683 edflags);
1684 if (ret)
1685 return ret;
1686 }
1687
1688 lr->lines[i].edflags = edflags;
1689
1690 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
1691
1692 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
1693 offset);
1694 }
1695
1696 lr->device_unregistered_nb.notifier_call = linereq_unregistered_notify;
1697 ret = blocking_notifier_chain_register(&gdev->device_notifier,
1698 &lr->device_unregistered_nb);
1699 if (ret)
1700 return ret;
1701
1702 FD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,
1703 anon_inode_getfile("gpio-line", &line_fileops, lr,
1704 O_RDONLY | O_CLOEXEC));
1705 if (fdf.err)
1706 return fdf.err;
1707 retain_and_null_ptr(lr);
1708
1709 ulr.fd = fd_prepare_fd(fdf);
1710 if (copy_to_user(ip, &ulr, sizeof(ulr)))
1711 return -EFAULT;
1712
1713 fd_publish(fdf);
1714
1715 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
1716 ulr.num_lines);
1717
1718 return 0;
1719}
1720
1721#ifdef CONFIG_GPIO_CDEV_V1
1722
1723/*
1724 * GPIO line event management
1725 */
1726
1727/**
1728 * struct lineevent_state - contains the state of a userspace event
1729 * @gdev: the GPIO device the event pertains to
1730 * @label: consumer label used to tag descriptors
1731 * @desc: the GPIO descriptor held by this event
1732 * @eflags: the event flags this line was requested with
1733 * @irq: the interrupt that trigger in response to events on this GPIO
1734 * @wait: wait queue that handles blocking reads of events
1735 * @device_unregistered_nb: notifier block for receiving gdev unregister events
1736 * @events: KFIFO for the GPIO events
1737 * @timestamp: cache for the timestamp storing it between hardirq
1738 * and IRQ thread, used to bring the timestamp close to the actual
1739 * event
1740 */
1741struct lineevent_state {
1742 struct gpio_device *gdev;
1743 const char *label;
1744 struct gpio_desc *desc;
1745 u32 eflags;
1746 int irq;
1747 wait_queue_head_t wait;
1748 struct notifier_block device_unregistered_nb;
1749 DECLARE_KFIFO(events, struct gpioevent_data, 16);
1750 u64 timestamp;
1751};
1752
1753#define GPIOEVENT_REQUEST_VALID_FLAGS \
1754 (GPIOEVENT_REQUEST_RISING_EDGE | \
1755 GPIOEVENT_REQUEST_FALLING_EDGE)
1756
1757static __poll_t lineevent_poll(struct file *file,
1758 struct poll_table_struct *wait)
1759{
1760 struct lineevent_state *le = file->private_data;
1761 __poll_t events = 0;
1762
1763 guard(srcu)(&le->gdev->srcu);
1764
1765 if (!rcu_access_pointer(le->gdev->chip))
1766 return EPOLLHUP | EPOLLERR;
1767
1768 poll_wait(file, &le->wait, wait);
1769
1770 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
1771 events = EPOLLIN | EPOLLRDNORM;
1772
1773 return events;
1774}
1775
1776static int lineevent_unregistered_notify(struct notifier_block *nb,
1777 unsigned long action, void *data)
1778{
1779 struct lineevent_state *le = container_of(nb, struct lineevent_state,
1780 device_unregistered_nb);
1781
1782 wake_up_poll(&le->wait, EPOLLIN | EPOLLERR);
1783
1784 return NOTIFY_OK;
1785}
1786
1787struct compat_gpioeevent_data {
1788 compat_u64 timestamp;
1789 u32 id;
1790};
1791
1792static ssize_t lineevent_read(struct file *file, char __user *buf,
1793 size_t count, loff_t *f_ps)
1794{
1795 struct lineevent_state *le = file->private_data;
1796 struct gpioevent_data ge;
1797 ssize_t bytes_read = 0;
1798 ssize_t ge_size;
1799 int ret;
1800
1801 guard(srcu)(&le->gdev->srcu);
1802
1803 if (!rcu_access_pointer(le->gdev->chip))
1804 return -ENODEV;
1805
1806 /*
1807 * When compatible system call is being used the struct gpioevent_data,
1808 * in case of at least ia32, has different size due to the alignment
1809 * differences. Because we have first member 64 bits followed by one of
1810 * 32 bits there is no gap between them. The only difference is the
1811 * padding at the end of the data structure. Hence, we calculate the
1812 * actual sizeof() and pass this as an argument to copy_to_user() to
1813 * drop unneeded bytes from the output.
1814 */
1815 if (compat_need_64bit_alignment_fixup())
1816 ge_size = sizeof(struct compat_gpioeevent_data);
1817 else
1818 ge_size = sizeof(struct gpioevent_data);
1819 if (count < ge_size)
1820 return -EINVAL;
1821
1822 do {
1823 scoped_guard(spinlock, &le->wait.lock) {
1824 if (kfifo_is_empty(&le->events)) {
1825 if (bytes_read)
1826 return bytes_read;
1827
1828 if (file->f_flags & O_NONBLOCK)
1829 return -EAGAIN;
1830
1831 ret = wait_event_interruptible_locked(le->wait,
1832 !kfifo_is_empty(&le->events));
1833 if (ret)
1834 return ret;
1835 }
1836
1837 if (kfifo_out(&le->events, &ge, 1) != 1) {
1838 /*
1839 * This should never happen - we hold the
1840 * lock from the moment we learned the fifo
1841 * is no longer empty until now.
1842 */
1843 WARN(1, "failed to read from non-empty kfifo");
1844 return -EIO;
1845 }
1846 }
1847
1848 if (copy_to_user(buf + bytes_read, &ge, ge_size))
1849 return -EFAULT;
1850 bytes_read += ge_size;
1851 } while (count >= bytes_read + ge_size);
1852
1853 return bytes_read;
1854}
1855
1856static void lineevent_free(struct lineevent_state *le)
1857{
1858 if (le->device_unregistered_nb.notifier_call)
1859 blocking_notifier_chain_unregister(&le->gdev->device_notifier,
1860 &le->device_unregistered_nb);
1861 if (le->irq)
1862 free_irq_label(free_irq(le->irq, le));
1863 if (le->desc)
1864 gpiod_free(le->desc);
1865 kfree(le->label);
1866 gpio_device_put(le->gdev);
1867 kfree(le);
1868}
1869
1870static int lineevent_release(struct inode *inode, struct file *file)
1871{
1872 lineevent_free(file->private_data);
1873 return 0;
1874}
1875
1876static long lineevent_ioctl(struct file *file, unsigned int cmd,
1877 unsigned long arg)
1878{
1879 struct lineevent_state *le = file->private_data;
1880 void __user *ip = (void __user *)arg;
1881 struct gpiohandle_data ghd;
1882
1883 guard(srcu)(&le->gdev->srcu);
1884
1885 if (!rcu_access_pointer(le->gdev->chip))
1886 return -ENODEV;
1887
1888 /*
1889 * We can get the value for an event line but not set it,
1890 * because it is input by definition.
1891 */
1892 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
1893 int val;
1894
1895 memset(&ghd, 0, sizeof(ghd));
1896
1897 val = gpiod_get_value_cansleep(le->desc);
1898 if (val < 0)
1899 return val;
1900 ghd.values[0] = val;
1901
1902 if (copy_to_user(ip, &ghd, sizeof(ghd)))
1903 return -EFAULT;
1904
1905 return 0;
1906 }
1907 return -EINVAL;
1908}
1909
1910#ifdef CONFIG_COMPAT
1911static long lineevent_ioctl_compat(struct file *file, unsigned int cmd,
1912 unsigned long arg)
1913{
1914 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1915}
1916#endif
1917
1918static const struct file_operations lineevent_fileops = {
1919 .release = lineevent_release,
1920 .read = lineevent_read,
1921 .poll = lineevent_poll,
1922 .owner = THIS_MODULE,
1923 .llseek = noop_llseek,
1924 .unlocked_ioctl = lineevent_ioctl,
1925#ifdef CONFIG_COMPAT
1926 .compat_ioctl = lineevent_ioctl_compat,
1927#endif
1928};
1929
1930static irqreturn_t lineevent_irq_thread(int irq, void *p)
1931{
1932 struct lineevent_state *le = p;
1933 struct gpioevent_data ge;
1934 int ret;
1935
1936 /* Do not leak kernel stack to userspace */
1937 memset(&ge, 0, sizeof(ge));
1938
1939 /*
1940 * We may be running from a nested threaded interrupt in which case
1941 * we didn't get the timestamp from lineevent_irq_handler().
1942 */
1943 if (!le->timestamp)
1944 ge.timestamp = ktime_get_ns();
1945 else
1946 ge.timestamp = le->timestamp;
1947
1948 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
1949 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
1950 int level = gpiod_get_value_cansleep(le->desc);
1951
1952 if (level)
1953 /* Emit low-to-high event */
1954 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
1955 else
1956 /* Emit high-to-low event */
1957 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
1958 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
1959 /* Emit low-to-high event */
1960 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
1961 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
1962 /* Emit high-to-low event */
1963 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
1964 } else {
1965 return IRQ_NONE;
1966 }
1967
1968 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
1969 1, &le->wait.lock);
1970 if (ret)
1971 wake_up_poll(&le->wait, EPOLLIN);
1972 else
1973 pr_debug_ratelimited("event FIFO is full - event dropped\n");
1974
1975 return IRQ_HANDLED;
1976}
1977
1978static irqreturn_t lineevent_irq_handler(int irq, void *p)
1979{
1980 struct lineevent_state *le = p;
1981
1982 /*
1983 * Just store the timestamp in hardirq context so we get it as
1984 * close in time as possible to the actual event.
1985 */
1986 le->timestamp = ktime_get_ns();
1987
1988 return IRQ_WAKE_THREAD;
1989}
1990
1991DEFINE_FREE(lineevent_free, struct lineevent_state *, if (!IS_ERR_OR_NULL(_T)) lineevent_free(_T))
1992
1993static int lineevent_create(struct gpio_device *gdev, void __user *ip)
1994{
1995 struct gpioevent_request eventreq;
1996 struct lineevent_state *le __free(lineevent_free) = NULL;
1997 struct gpio_desc *desc;
1998 u32 offset;
1999 u32 lflags;
2000 u32 eflags;
2001 int ret;
2002 int irq, irqflags = 0;
2003 char *label;
2004
2005 if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
2006 return -EFAULT;
2007
2008 offset = eventreq.lineoffset;
2009 lflags = eventreq.handleflags;
2010 eflags = eventreq.eventflags;
2011
2012 desc = gpio_device_get_desc(gdev, offset);
2013 if (IS_ERR(desc))
2014 return PTR_ERR(desc);
2015
2016 /* Return an error if a unknown flag is set */
2017 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
2018 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
2019 return -EINVAL;
2020
2021 /* This is just wrong: we don't look for events on output lines */
2022 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
2023 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
2024 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
2025 return -EINVAL;
2026
2027 /* Only one bias flag can be set. */
2028 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
2029 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
2030 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
2031 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
2032 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
2033 return -EINVAL;
2034
2035 le = kzalloc_obj(*le);
2036 if (!le)
2037 return -ENOMEM;
2038 le->gdev = gpio_device_get(gdev);
2039
2040 if (eventreq.consumer_label[0] != '\0') {
2041 /* label is only initialized if consumer_label is set */
2042 le->label = kstrndup(eventreq.consumer_label,
2043 sizeof(eventreq.consumer_label) - 1,
2044 GFP_KERNEL);
2045 if (!le->label)
2046 return -ENOMEM;
2047 }
2048
2049 ret = gpiod_request_user(desc, le->label);
2050 if (ret)
2051 return ret;
2052 le->desc = desc;
2053 le->eflags = eflags;
2054
2055 linehandle_flags_to_desc_flags(lflags, &desc->flags);
2056
2057 ret = gpiod_direction_input(desc);
2058 if (ret)
2059 return ret;
2060
2061 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
2062
2063 irq = gpiod_to_irq(desc);
2064 if (irq <= 0)
2065 return -ENODEV;
2066
2067 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
2068 irqflags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &desc->flags) ?
2069 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
2070 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
2071 irqflags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &desc->flags) ?
2072 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
2073 irqflags |= IRQF_ONESHOT;
2074
2075 INIT_KFIFO(le->events);
2076 init_waitqueue_head(&le->wait);
2077
2078 le->device_unregistered_nb.notifier_call = lineevent_unregistered_notify;
2079 ret = blocking_notifier_chain_register(&gdev->device_notifier,
2080 &le->device_unregistered_nb);
2081 if (ret)
2082 return ret;
2083
2084 label = make_irq_label(le->label);
2085 if (IS_ERR(label))
2086 return PTR_ERR(label);
2087
2088 /* Request a thread to read the events */
2089 ret = request_threaded_irq(irq,
2090 lineevent_irq_handler,
2091 lineevent_irq_thread,
2092 irqflags,
2093 label,
2094 le);
2095 if (ret) {
2096 free_irq_label(label);
2097 return ret;
2098 }
2099
2100 le->irq = irq;
2101
2102 FD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,
2103 anon_inode_getfile("gpio-event", &lineevent_fileops, le,
2104 O_RDONLY | O_CLOEXEC));
2105 if (fdf.err)
2106 return fdf.err;
2107 retain_and_null_ptr(le);
2108
2109 eventreq.fd = fd_prepare_fd(fdf);
2110 if (copy_to_user(ip, &eventreq, sizeof(eventreq)))
2111 return -EFAULT;
2112
2113 fd_publish(fdf);
2114
2115 return 0;
2116}
2117
2118static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2,
2119 struct gpioline_info *info_v1)
2120{
2121 u64 flagsv2 = info_v2->flags;
2122
2123 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name));
2124 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer));
2125 info_v1->line_offset = info_v2->offset;
2126 info_v1->flags = 0;
2127
2128 if (flagsv2 & GPIO_V2_LINE_FLAG_USED)
2129 info_v1->flags |= GPIOLINE_FLAG_KERNEL;
2130
2131 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT)
2132 info_v1->flags |= GPIOLINE_FLAG_IS_OUT;
2133
2134 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
2135 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
2136
2137 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN)
2138 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN;
2139 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE)
2140 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE;
2141
2142 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)
2143 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
2144 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN)
2145 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
2146 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED)
2147 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
2148}
2149
2150static void gpio_v2_line_info_changed_to_v1(
2151 struct gpio_v2_line_info_changed *lic_v2,
2152 struct gpioline_info_changed *lic_v1)
2153{
2154 memset(lic_v1, 0, sizeof(*lic_v1));
2155 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info);
2156 lic_v1->timestamp = lic_v2->timestamp_ns;
2157 lic_v1->event_type = lic_v2->event_type;
2158}
2159
2160#endif /* CONFIG_GPIO_CDEV_V1 */
2161
2162static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
2163 struct gpio_v2_line_info *info, bool atomic)
2164{
2165 u32 debounce_period_us;
2166 unsigned long dflags;
2167 const char *label;
2168
2169 CLASS(gpio_chip_guard, guard)(desc);
2170 if (!guard.gc)
2171 return;
2172
2173 memset(info, 0, sizeof(*info));
2174 info->offset = gpiod_hwgpio(desc);
2175
2176 if (desc->name)
2177 strscpy(info->name, desc->name, sizeof(info->name));
2178
2179 dflags = READ_ONCE(desc->flags);
2180
2181 scoped_guard(srcu, &desc->gdev->desc_srcu) {
2182 label = gpiod_get_label(desc);
2183 if (label && test_bit(GPIOD_FLAG_REQUESTED, &dflags))
2184 strscpy(info->consumer, label,
2185 sizeof(info->consumer));
2186 }
2187
2188 /*
2189 * Userspace only need know that the kernel is using this GPIO so it
2190 * can't use it.
2191 * The calculation of the used flag is slightly racy, as it may read
2192 * desc, gc and pinctrl state without a lock covering all three at
2193 * once. Worst case if the line is in transition and the calculation
2194 * is inconsistent then it looks to the user like they performed the
2195 * read on the other side of the transition - but that can always
2196 * happen.
2197 * The definitive test that a line is available to userspace is to
2198 * request it.
2199 */
2200 if (test_bit(GPIOD_FLAG_REQUESTED, &dflags) ||
2201 test_bit(GPIOD_FLAG_IS_HOGGED, &dflags) ||
2202 test_bit(GPIOD_FLAG_EXPORT, &dflags) ||
2203 test_bit(GPIOD_FLAG_SYSFS, &dflags) ||
2204 !gpiochip_line_is_valid(guard.gc, info->offset)) {
2205 info->flags |= GPIO_V2_LINE_FLAG_USED;
2206 } else if (!atomic) {
2207 if (!pinctrl_gpio_can_use_line(guard.gc, info->offset))
2208 info->flags |= GPIO_V2_LINE_FLAG_USED;
2209 }
2210
2211 if (test_bit(GPIOD_FLAG_IS_OUT, &dflags))
2212 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
2213 else
2214 info->flags |= GPIO_V2_LINE_FLAG_INPUT;
2215
2216 if (test_bit(GPIOD_FLAG_ACTIVE_LOW, &dflags))
2217 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
2218
2219 if (test_bit(GPIOD_FLAG_OPEN_DRAIN, &dflags))
2220 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
2221 if (test_bit(GPIOD_FLAG_OPEN_SOURCE, &dflags))
2222 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
2223
2224 if (test_bit(GPIOD_FLAG_BIAS_DISABLE, &dflags))
2225 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
2226 if (test_bit(GPIOD_FLAG_PULL_DOWN, &dflags))
2227 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
2228 if (test_bit(GPIOD_FLAG_PULL_UP, &dflags))
2229 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
2230
2231 if (test_bit(GPIOD_FLAG_EDGE_RISING, &dflags))
2232 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
2233 if (test_bit(GPIOD_FLAG_EDGE_FALLING, &dflags))
2234 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
2235
2236 if (test_bit(GPIOD_FLAG_EVENT_CLOCK_REALTIME, &dflags))
2237 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME;
2238 else if (test_bit(GPIOD_FLAG_EVENT_CLOCK_HTE, &dflags))
2239 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE;
2240
2241 debounce_period_us = READ_ONCE(desc->debounce_period_us);
2242 if (debounce_period_us) {
2243 info->attrs[info->num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
2244 info->attrs[info->num_attrs].debounce_period_us =
2245 debounce_period_us;
2246 info->num_attrs++;
2247 }
2248}
2249
2250struct gpio_chardev_data {
2251 struct gpio_device *gdev;
2252 wait_queue_head_t wait;
2253 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32);
2254 struct notifier_block lineinfo_changed_nb;
2255 struct notifier_block device_unregistered_nb;
2256 unsigned long *watched_lines;
2257#ifdef CONFIG_GPIO_CDEV_V1
2258 atomic_t watch_abi_version;
2259#endif
2260 struct file *fp;
2261};
2262
2263static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip)
2264{
2265 struct gpio_device *gdev = cdev->gdev;
2266 struct gpiochip_info chipinfo;
2267
2268 memset(&chipinfo, 0, sizeof(chipinfo));
2269
2270 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name));
2271 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label));
2272 chipinfo.lines = gdev->ngpio;
2273 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
2274 return -EFAULT;
2275 return 0;
2276}
2277
2278#ifdef CONFIG_GPIO_CDEV_V1
2279/*
2280 * returns 0 if the versions match, else the previously selected ABI version
2281 */
2282static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata,
2283 unsigned int version)
2284{
2285 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version);
2286
2287 if (abiv == version)
2288 return 0;
2289
2290 return abiv;
2291}
2292
2293static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
2294 bool watch)
2295{
2296 struct gpio_desc *desc;
2297 struct gpioline_info lineinfo;
2298 struct gpio_v2_line_info lineinfo_v2;
2299
2300 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2301 return -EFAULT;
2302
2303 /* this doubles as a range check on line_offset */
2304 desc = gpio_device_get_desc(cdev->gdev, lineinfo.line_offset);
2305 if (IS_ERR(desc))
2306 return PTR_ERR(desc);
2307
2308 if (watch) {
2309 if (lineinfo_ensure_abi_version(cdev, 1))
2310 return -EPERM;
2311
2312 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
2313 return -EBUSY;
2314 }
2315
2316 gpio_desc_to_lineinfo(desc, &lineinfo_v2, false);
2317 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
2318
2319 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2320 if (watch)
2321 clear_bit(lineinfo.line_offset, cdev->watched_lines);
2322 return -EFAULT;
2323 }
2324
2325 return 0;
2326}
2327#endif
2328
2329static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
2330 bool watch)
2331{
2332 struct gpio_desc *desc;
2333 struct gpio_v2_line_info lineinfo;
2334
2335 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2336 return -EFAULT;
2337
2338 if (!mem_is_zero(lineinfo.padding, sizeof(lineinfo.padding)))
2339 return -EINVAL;
2340
2341 desc = gpio_device_get_desc(cdev->gdev, lineinfo.offset);
2342 if (IS_ERR(desc))
2343 return PTR_ERR(desc);
2344
2345 if (watch) {
2346#ifdef CONFIG_GPIO_CDEV_V1
2347 if (lineinfo_ensure_abi_version(cdev, 2))
2348 return -EPERM;
2349#endif
2350 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
2351 return -EBUSY;
2352 }
2353 gpio_desc_to_lineinfo(desc, &lineinfo, false);
2354
2355 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2356 if (watch)
2357 clear_bit(lineinfo.offset, cdev->watched_lines);
2358 return -EFAULT;
2359 }
2360
2361 return 0;
2362}
2363
2364static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip)
2365{
2366 __u32 offset;
2367
2368 if (copy_from_user(&offset, ip, sizeof(offset)))
2369 return -EFAULT;
2370
2371 if (offset >= cdev->gdev->ngpio)
2372 return -EINVAL;
2373
2374 if (!test_and_clear_bit(offset, cdev->watched_lines))
2375 return -EBUSY;
2376
2377 return 0;
2378}
2379
2380/*
2381 * gpio_ioctl() - ioctl handler for the GPIO chardev
2382 */
2383static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2384{
2385 struct gpio_chardev_data *cdev = file->private_data;
2386 struct gpio_device *gdev = cdev->gdev;
2387 void __user *ip = (void __user *)arg;
2388
2389 guard(srcu)(&gdev->srcu);
2390
2391 /* We fail any subsequent ioctl():s when the chip is gone */
2392 if (!rcu_access_pointer(gdev->chip))
2393 return -ENODEV;
2394
2395 /* Fill in the struct and pass to userspace */
2396 switch (cmd) {
2397 case GPIO_GET_CHIPINFO_IOCTL:
2398 return chipinfo_get(cdev, ip);
2399#ifdef CONFIG_GPIO_CDEV_V1
2400 case GPIO_GET_LINEHANDLE_IOCTL:
2401 return linehandle_create(gdev, ip);
2402 case GPIO_GET_LINEEVENT_IOCTL:
2403 return lineevent_create(gdev, ip);
2404 case GPIO_GET_LINEINFO_IOCTL:
2405 return lineinfo_get_v1(cdev, ip, false);
2406 case GPIO_GET_LINEINFO_WATCH_IOCTL:
2407 return lineinfo_get_v1(cdev, ip, true);
2408#endif /* CONFIG_GPIO_CDEV_V1 */
2409 case GPIO_V2_GET_LINEINFO_IOCTL:
2410 return lineinfo_get(cdev, ip, false);
2411 case GPIO_V2_GET_LINEINFO_WATCH_IOCTL:
2412 return lineinfo_get(cdev, ip, true);
2413 case GPIO_V2_GET_LINE_IOCTL:
2414 return linereq_create(gdev, ip);
2415 case GPIO_GET_LINEINFO_UNWATCH_IOCTL:
2416 return lineinfo_unwatch(cdev, ip);
2417 default:
2418 return -EINVAL;
2419 }
2420}
2421
2422#ifdef CONFIG_COMPAT
2423static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
2424 unsigned long arg)
2425{
2426 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2427}
2428#endif
2429
2430struct lineinfo_changed_ctx {
2431 struct work_struct work;
2432 struct gpio_v2_line_info_changed chg;
2433 struct gpio_device *gdev;
2434 struct gpio_chardev_data *cdev;
2435};
2436
2437static void lineinfo_changed_func(struct work_struct *work)
2438{
2439 struct lineinfo_changed_ctx *ctx =
2440 container_of(work, struct lineinfo_changed_ctx, work);
2441 struct gpio_chip *gc;
2442 int ret;
2443
2444 if (!(ctx->chg.info.flags & GPIO_V2_LINE_FLAG_USED)) {
2445 /*
2446 * If nobody set the USED flag earlier, let's see with pinctrl
2447 * now. We're doing this late because it's a sleeping function.
2448 * Pin functions are in general much more static and while it's
2449 * not 100% bullet-proof, it's good enough for most cases.
2450 */
2451 scoped_guard(srcu, &ctx->gdev->srcu) {
2452 gc = srcu_dereference(ctx->gdev->chip, &ctx->gdev->srcu);
2453 if (gc &&
2454 !pinctrl_gpio_can_use_line(gc, ctx->chg.info.offset))
2455 ctx->chg.info.flags |= GPIO_V2_LINE_FLAG_USED;
2456 }
2457 }
2458
2459 ret = kfifo_in_spinlocked(&ctx->cdev->events, &ctx->chg, 1,
2460 &ctx->cdev->wait.lock);
2461 if (ret)
2462 wake_up_poll(&ctx->cdev->wait, EPOLLIN);
2463 else
2464 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");
2465
2466 gpio_device_put(ctx->gdev);
2467 fput(ctx->cdev->fp);
2468 kfree(ctx);
2469}
2470
2471static int lineinfo_changed_notify(struct notifier_block *nb,
2472 unsigned long action, void *data)
2473{
2474 struct gpio_chardev_data *cdev =
2475 container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
2476 struct lineinfo_changed_ctx *ctx;
2477 struct gpio_desc *desc = data;
2478 struct file *fp;
2479
2480 if (!test_bit(gpiod_hwgpio(desc), cdev->watched_lines))
2481 return NOTIFY_DONE;
2482
2483 /* Keep the file descriptor alive for the duration of the notification. */
2484 fp = get_file_active(&cdev->fp);
2485 if (!fp)
2486 /* Chardev file descriptor was or is being released. */
2487 return NOTIFY_DONE;
2488
2489 /*
2490 * If this is called from atomic context (for instance: with a spinlock
2491 * taken by the atomic notifier chain), any sleeping calls must be done
2492 * outside of this function in process context of the dedicated
2493 * workqueue.
2494 *
2495 * Let's gather as much info as possible from the descriptor and
2496 * postpone just the call to pinctrl_gpio_can_use_line() until the work
2497 * is executed.
2498 */
2499
2500 ctx = kzalloc_obj(*ctx, GFP_ATOMIC);
2501 if (!ctx) {
2502 pr_err("Failed to allocate memory for line info notification\n");
2503 fput(fp);
2504 return NOTIFY_DONE;
2505 }
2506
2507 ctx->chg.event_type = action;
2508 ctx->chg.timestamp_ns = ktime_get_ns();
2509 gpio_desc_to_lineinfo(desc, &ctx->chg.info, true);
2510 /* Keep the GPIO device alive until we emit the event. */
2511 ctx->gdev = gpio_device_get(desc->gdev);
2512 ctx->cdev = cdev;
2513
2514 INIT_WORK(&ctx->work, lineinfo_changed_func);
2515 queue_work(ctx->gdev->line_state_wq, &ctx->work);
2516
2517 return NOTIFY_OK;
2518}
2519
2520static int gpio_device_unregistered_notify(struct notifier_block *nb,
2521 unsigned long action, void *data)
2522{
2523 struct gpio_chardev_data *cdev = container_of(nb,
2524 struct gpio_chardev_data,
2525 device_unregistered_nb);
2526
2527 wake_up_poll(&cdev->wait, EPOLLIN | EPOLLERR);
2528
2529 return NOTIFY_OK;
2530}
2531
2532static __poll_t lineinfo_watch_poll(struct file *file,
2533 struct poll_table_struct *pollt)
2534{
2535 struct gpio_chardev_data *cdev = file->private_data;
2536 __poll_t events = 0;
2537
2538 guard(srcu)(&cdev->gdev->srcu);
2539
2540 if (!rcu_access_pointer(cdev->gdev->chip))
2541 return EPOLLHUP | EPOLLERR;
2542
2543 poll_wait(file, &cdev->wait, pollt);
2544
2545 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events,
2546 &cdev->wait.lock))
2547 events = EPOLLIN | EPOLLRDNORM;
2548
2549 return events;
2550}
2551
2552static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
2553 size_t count, loff_t *off)
2554{
2555 struct gpio_chardev_data *cdev = file->private_data;
2556 struct gpio_v2_line_info_changed event;
2557 ssize_t bytes_read = 0;
2558 int ret;
2559 size_t event_size;
2560
2561 guard(srcu)(&cdev->gdev->srcu);
2562
2563 if (!rcu_access_pointer(cdev->gdev->chip))
2564 return -ENODEV;
2565
2566#ifndef CONFIG_GPIO_CDEV_V1
2567 event_size = sizeof(struct gpio_v2_line_info_changed);
2568 if (count < event_size)
2569 return -EINVAL;
2570#endif
2571
2572 do {
2573 scoped_guard(spinlock, &cdev->wait.lock) {
2574 if (kfifo_is_empty(&cdev->events)) {
2575 if (bytes_read)
2576 return bytes_read;
2577
2578 if (file->f_flags & O_NONBLOCK)
2579 return -EAGAIN;
2580
2581 ret = wait_event_interruptible_locked(cdev->wait,
2582 !kfifo_is_empty(&cdev->events));
2583 if (ret)
2584 return ret;
2585 }
2586#ifdef CONFIG_GPIO_CDEV_V1
2587 /* must be after kfifo check so watch_abi_version is set */
2588 if (atomic_read(&cdev->watch_abi_version) == 2)
2589 event_size = sizeof(struct gpio_v2_line_info_changed);
2590 else
2591 event_size = sizeof(struct gpioline_info_changed);
2592 if (count < event_size)
2593 return -EINVAL;
2594#endif
2595 if (kfifo_out(&cdev->events, &event, 1) != 1) {
2596 /*
2597 * This should never happen - we hold the
2598 * lock from the moment we learned the fifo
2599 * is no longer empty until now.
2600 */
2601 WARN(1, "failed to read from non-empty kfifo");
2602 return -EIO;
2603 }
2604 }
2605
2606#ifdef CONFIG_GPIO_CDEV_V1
2607 if (event_size == sizeof(struct gpio_v2_line_info_changed)) {
2608 if (copy_to_user(buf + bytes_read, &event, event_size))
2609 return -EFAULT;
2610 } else {
2611 struct gpioline_info_changed event_v1;
2612
2613 gpio_v2_line_info_changed_to_v1(&event, &event_v1);
2614 if (copy_to_user(buf + bytes_read, &event_v1,
2615 event_size))
2616 return -EFAULT;
2617 }
2618#else
2619 if (copy_to_user(buf + bytes_read, &event, event_size))
2620 return -EFAULT;
2621#endif
2622 bytes_read += event_size;
2623 } while (count >= bytes_read + sizeof(event));
2624
2625 return bytes_read;
2626}
2627
2628/**
2629 * gpio_chrdev_open() - open the chardev for ioctl operations
2630 * @inode: inode for this chardev
2631 * @file: file struct for storing private data
2632 *
2633 * Returns:
2634 * 0 on success, or negative errno on failure.
2635 */
2636static int gpio_chrdev_open(struct inode *inode, struct file *file)
2637{
2638 struct gpio_device *gdev = container_of(inode->i_cdev,
2639 struct gpio_device, chrdev);
2640 struct gpio_chardev_data *cdev;
2641 int ret = -ENOMEM;
2642
2643 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
2644 if (!cdev)
2645 return -ENOMEM;
2646
2647 cdev->watched_lines = bitmap_zalloc(gdev->ngpio, GFP_KERNEL);
2648 if (!cdev->watched_lines)
2649 goto out_free_cdev;
2650
2651 init_waitqueue_head(&cdev->wait);
2652 INIT_KFIFO(cdev->events);
2653 cdev->gdev = gpio_device_get(gdev);
2654
2655 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
2656 scoped_guard(write_lock_irqsave, &gdev->line_state_lock)
2657 ret = raw_notifier_chain_register(&gdev->line_state_notifier,
2658 &cdev->lineinfo_changed_nb);
2659 if (ret)
2660 goto out_free_bitmap;
2661
2662 cdev->device_unregistered_nb.notifier_call =
2663 gpio_device_unregistered_notify;
2664 ret = blocking_notifier_chain_register(&gdev->device_notifier,
2665 &cdev->device_unregistered_nb);
2666 if (ret)
2667 goto out_unregister_line_notifier;
2668
2669 file->private_data = cdev;
2670 cdev->fp = file;
2671
2672 ret = nonseekable_open(inode, file);
2673 if (ret)
2674 goto out_unregister_device_notifier;
2675
2676 return ret;
2677
2678out_unregister_device_notifier:
2679 blocking_notifier_chain_unregister(&gdev->device_notifier,
2680 &cdev->device_unregistered_nb);
2681out_unregister_line_notifier:
2682 scoped_guard(write_lock_irqsave, &gdev->line_state_lock)
2683 raw_notifier_chain_unregister(&gdev->line_state_notifier,
2684 &cdev->lineinfo_changed_nb);
2685out_free_bitmap:
2686 gpio_device_put(gdev);
2687 bitmap_free(cdev->watched_lines);
2688out_free_cdev:
2689 kfree(cdev);
2690 return ret;
2691}
2692
2693/**
2694 * gpio_chrdev_release() - close chardev after ioctl operations
2695 * @inode: inode for this chardev
2696 * @file: file struct for storing private data
2697 *
2698 * Returns:
2699 * 0 on success, or negative errno on failure.
2700 */
2701static int gpio_chrdev_release(struct inode *inode, struct file *file)
2702{
2703 struct gpio_chardev_data *cdev = file->private_data;
2704 struct gpio_device *gdev = cdev->gdev;
2705
2706 blocking_notifier_chain_unregister(&gdev->device_notifier,
2707 &cdev->device_unregistered_nb);
2708 scoped_guard(write_lock_irqsave, &gdev->line_state_lock)
2709 raw_notifier_chain_unregister(&gdev->line_state_notifier,
2710 &cdev->lineinfo_changed_nb);
2711 bitmap_free(cdev->watched_lines);
2712 gpio_device_put(gdev);
2713 kfree(cdev);
2714
2715 return 0;
2716}
2717
2718static const struct file_operations gpio_fileops = {
2719 .release = gpio_chrdev_release,
2720 .open = gpio_chrdev_open,
2721 .poll = lineinfo_watch_poll,
2722 .read = lineinfo_watch_read,
2723 .owner = THIS_MODULE,
2724 .unlocked_ioctl = gpio_ioctl,
2725#ifdef CONFIG_COMPAT
2726 .compat_ioctl = gpio_ioctl_compat,
2727#endif
2728};
2729
2730int gpiolib_cdev_register(struct gpio_chip *gc, dev_t devt)
2731{
2732 struct gpio_device *gdev = gc->gpiodev;
2733 int ret;
2734
2735 cdev_init(&gdev->chrdev, &gpio_fileops);
2736 gdev->chrdev.owner = THIS_MODULE;
2737 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
2738
2739 gdev->line_state_wq = alloc_ordered_workqueue("%s", WQ_HIGHPRI,
2740 dev_name(&gdev->dev));
2741 if (!gdev->line_state_wq)
2742 return -ENOMEM;
2743
2744 ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
2745 if (ret) {
2746 destroy_workqueue(gdev->line_state_wq);
2747 return ret;
2748 }
2749
2750 gpiochip_dbg(gc, "added GPIO chardev (%d:%d)\n", MAJOR(devt), gdev->id);
2751
2752 return 0;
2753}
2754
2755void gpiolib_cdev_unregister(struct gpio_device *gdev)
2756{
2757 destroy_workqueue(gdev->line_state_wq);
2758 cdev_device_del(&gdev->chrdev, &gdev->dev);
2759 blocking_notifier_call_chain(&gdev->device_notifier, 0, NULL);
2760}