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