projects / linux-block.git / blame_incremental
? search:
summary | shortlog | log | commit | commitdiff | tree
blob | blame (non-incremental) | history | HEAD
Merge tag 'for-6.8/block-2024-01-18' of git://git.kernel.dk/linux
[linux-block.git] / drivers / gpio / gpiolib-cdev.c
... / ...
CommitLineData
1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/anon_inodes.h>
4#include <linux/atomic.h>
5#include <linux/bitmap.h>
6#include <linux/build_bug.h>
7#include <linux/cdev.h>
8#include <linux/cleanup.h>
9#include <linux/compat.h>
10#include <linux/compiler.h>
11#include <linux/device.h>
12#include <linux/err.h>
13#include <linux/file.h>
14#include <linux/gpio.h>
15#include <linux/gpio/driver.h>
16#include <linux/hte.h>
17#include <linux/interrupt.h>
18#include <linux/irqreturn.h>
19#include <linux/kernel.h>
20#include <linux/kfifo.h>
21#include <linux/module.h>
22#include <linux/mutex.h>
23#include <linux/overflow.h>
24#include <linux/pinctrl/consumer.h>
25#include <linux/poll.h>
26#include <linux/rbtree.h>
27#include <linux/rwsem.h>
28#include <linux/seq_file.h>
29#include <linux/spinlock.h>
30#include <linux/timekeeping.h>
31#include <linux/uaccess.h>
32#include <linux/workqueue.h>
33
34#include <uapi/linux/gpio.h>
35
36#include "gpiolib.h"
37#include "gpiolib-cdev.h"
38
39/*
40 * Array sizes must ensure 64-bit alignment and not create holes in the
41 * struct packing.
42 */
43static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2));
44static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8));
45
46/*
47 * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility
48 */
49static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8));
50static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8));
51static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8));
52static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8));
53static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8));
54static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8));
55static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8));
56static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8));
57
58/* Character device interface to GPIO.
59 *
60 * The GPIO character device, /dev/gpiochipN, provides userspace an
61 * interface to gpiolib GPIOs via ioctl()s.
62 */
63
64typedef __poll_t (*poll_fn)(struct file *, struct poll_table_struct *);
65typedef long (*ioctl_fn)(struct file *, unsigned int, unsigned long);
66typedef ssize_t (*read_fn)(struct file *, char __user *,
67 size_t count, loff_t *);
68
69/*
70 * GPIO line handle management
71 */
72
73#ifdef CONFIG_GPIO_CDEV_V1
74/**
75 * struct linehandle_state - contains the state of a userspace handle
76 * @gdev: the GPIO device the handle pertains to
77 * @label: consumer label used to tag descriptors
78 * @descs: the GPIO descriptors held by this handle
79 * @num_descs: the number of descriptors held in the descs array
80 */
81struct linehandle_state {
82 struct gpio_device *gdev;
83 const char *label;
84 struct gpio_desc *descs[GPIOHANDLES_MAX];
85 u32 num_descs;
86};
87
88#define GPIOHANDLE_REQUEST_VALID_FLAGS \
89 (GPIOHANDLE_REQUEST_INPUT | \
90 GPIOHANDLE_REQUEST_OUTPUT | \
91 GPIOHANDLE_REQUEST_ACTIVE_LOW | \
92 GPIOHANDLE_REQUEST_BIAS_PULL_UP | \
93 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \
94 GPIOHANDLE_REQUEST_BIAS_DISABLE | \
95 GPIOHANDLE_REQUEST_OPEN_DRAIN | \
96 GPIOHANDLE_REQUEST_OPEN_SOURCE)
97
98static int linehandle_validate_flags(u32 flags)
99{
100 /* Return an error if an unknown flag is set */
101 if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
102 return -EINVAL;
103
104 /*
105 * Do not allow both INPUT & OUTPUT flags to be set as they are
106 * contradictory.
107 */
108 if ((flags & GPIOHANDLE_REQUEST_INPUT) &&
109 (flags & GPIOHANDLE_REQUEST_OUTPUT))
110 return -EINVAL;
111
112 /*
113 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
114 * the hardware actually supports enabling both at the same time the
115 * electrical result would be disastrous.
116 */
117 if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
118 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
119 return -EINVAL;
120
121 /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
122 if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) &&
123 ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
124 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
125 return -EINVAL;
126
127 /* Bias flags only allowed for input or output mode. */
128 if (!((flags & GPIOHANDLE_REQUEST_INPUT) ||
129 (flags & GPIOHANDLE_REQUEST_OUTPUT)) &&
130 ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) ||
131 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) ||
132 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
133 return -EINVAL;
134
135 /* Only one bias flag can be set. */
136 if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
137 (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
138 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
139 ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
140 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
141 return -EINVAL;
142
143 return 0;
144}
145
146static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp)
147{
148 assign_bit(FLAG_ACTIVE_LOW, flagsp,
149 lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
150 assign_bit(FLAG_OPEN_DRAIN, flagsp,
151 lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
152 assign_bit(FLAG_OPEN_SOURCE, flagsp,
153 lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
154 assign_bit(FLAG_PULL_UP, flagsp,
155 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
156 assign_bit(FLAG_PULL_DOWN, flagsp,
157 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
158 assign_bit(FLAG_BIAS_DISABLE, flagsp,
159 lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
160}
161
162static long linehandle_set_config(struct linehandle_state *lh,
163 void __user *ip)
164{
165 struct gpiohandle_config gcnf;
166 struct gpio_desc *desc;
167 int i, ret;
168 u32 lflags;
169
170 if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
171 return -EFAULT;
172
173 lflags = gcnf.flags;
174 ret = linehandle_validate_flags(lflags);
175 if (ret)
176 return ret;
177
178 for (i = 0; i < lh->num_descs; i++) {
179 desc = lh->descs[i];
180 linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags);
181
182 /*
183 * Lines have to be requested explicitly for input
184 * or output, else the line will be treated "as is".
185 */
186 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
187 int val = !!gcnf.default_values[i];
188
189 ret = gpiod_direction_output(desc, val);
190 if (ret)
191 return ret;
192 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
193 ret = gpiod_direction_input(desc);
194 if (ret)
195 return ret;
196 }
197
198 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
199 }
200 return 0;
201}
202
203static long linehandle_ioctl(struct file *file, unsigned int cmd,
204 unsigned long arg)
205{
206 struct linehandle_state *lh = file->private_data;
207 void __user *ip = (void __user *)arg;
208 struct gpiohandle_data ghd;
209 DECLARE_BITMAP(vals, GPIOHANDLES_MAX);
210 unsigned int i;
211 int ret;
212
213 guard(rwsem_read)(&lh->gdev->sem);
214
215 if (!lh->gdev->chip)
216 return -ENODEV;
217
218 switch (cmd) {
219 case GPIOHANDLE_GET_LINE_VALUES_IOCTL:
220 /* NOTE: It's okay to read values of output lines */
221 ret = gpiod_get_array_value_complex(false, true,
222 lh->num_descs, lh->descs,
223 NULL, vals);
224 if (ret)
225 return ret;
226
227 memset(&ghd, 0, sizeof(ghd));
228 for (i = 0; i < lh->num_descs; i++)
229 ghd.values[i] = test_bit(i, vals);
230
231 if (copy_to_user(ip, &ghd, sizeof(ghd)))
232 return -EFAULT;
233
234 return 0;
235 case GPIOHANDLE_SET_LINE_VALUES_IOCTL:
236 /*
237 * All line descriptors were created at once with the same
238 * flags so just check if the first one is really output.
239 */
240 if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags))
241 return -EPERM;
242
243 if (copy_from_user(&ghd, ip, sizeof(ghd)))
244 return -EFAULT;
245
246 /* Clamp all values to [0,1] */
247 for (i = 0; i < lh->num_descs; i++)
248 __assign_bit(i, vals, ghd.values[i]);
249
250 /* Reuse the array setting function */
251 return gpiod_set_array_value_complex(false,
252 true,
253 lh->num_descs,
254 lh->descs,
255 NULL,
256 vals);
257 case GPIOHANDLE_SET_CONFIG_IOCTL:
258 return linehandle_set_config(lh, ip);
259 default:
260 return -EINVAL;
261 }
262}
263
264#ifdef CONFIG_COMPAT
265static long linehandle_ioctl_compat(struct file *file, unsigned int cmd,
266 unsigned long arg)
267{
268 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
269}
270#endif
271
272static void linehandle_free(struct linehandle_state *lh)
273{
274 int i;
275
276 for (i = 0; i < lh->num_descs; i++)
277 if (lh->descs[i])
278 gpiod_free(lh->descs[i]);
279 kfree(lh->label);
280 gpio_device_put(lh->gdev);
281 kfree(lh);
282}
283
284static int linehandle_release(struct inode *inode, struct file *file)
285{
286 linehandle_free(file->private_data);
287 return 0;
288}
289
290static const struct file_operations linehandle_fileops = {
291 .release = linehandle_release,
292 .owner = THIS_MODULE,
293 .llseek = noop_llseek,
294 .unlocked_ioctl = linehandle_ioctl,
295#ifdef CONFIG_COMPAT
296 .compat_ioctl = linehandle_ioctl_compat,
297#endif
298};
299
300static int linehandle_create(struct gpio_device *gdev, void __user *ip)
301{
302 struct gpiohandle_request handlereq;
303 struct linehandle_state *lh;
304 struct file *file;
305 int fd, i, ret;
306 u32 lflags;
307
308 if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
309 return -EFAULT;
310 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
311 return -EINVAL;
312
313 lflags = handlereq.flags;
314
315 ret = linehandle_validate_flags(lflags);
316 if (ret)
317 return ret;
318
319 lh = kzalloc(sizeof(*lh), GFP_KERNEL);
320 if (!lh)
321 return -ENOMEM;
322 lh->gdev = gpio_device_get(gdev);
323
324 if (handlereq.consumer_label[0] != '\0') {
325 /* label is only initialized if consumer_label is set */
326 lh->label = kstrndup(handlereq.consumer_label,
327 sizeof(handlereq.consumer_label) - 1,
328 GFP_KERNEL);
329 if (!lh->label) {
330 ret = -ENOMEM;
331 goto out_free_lh;
332 }
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 = gpiochip_get_desc(gdev->chip, offset);
341
342 if (IS_ERR(desc)) {
343 ret = PTR_ERR(desc);
344 goto out_free_lh;
345 }
346
347 ret = gpiod_request_user(desc, lh->label);
348 if (ret)
349 goto out_free_lh;
350 lh->descs[i] = desc;
351 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);
352
353 ret = gpiod_set_transitory(desc, false);
354 if (ret < 0)
355 goto out_free_lh;
356
357 /*
358 * Lines have to be requested explicitly for input
359 * or output, else the line will be treated "as is".
360 */
361 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
362 int val = !!handlereq.default_values[i];
363
364 ret = gpiod_direction_output(desc, val);
365 if (ret)
366 goto out_free_lh;
367 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
368 ret = gpiod_direction_input(desc);
369 if (ret)
370 goto out_free_lh;
371 }
372
373 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
374
375 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
376 offset);
377 }
378
379 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
380 if (fd < 0) {
381 ret = fd;
382 goto out_free_lh;
383 }
384
385 file = anon_inode_getfile("gpio-linehandle",
386 &linehandle_fileops,
387 lh,
388 O_RDONLY | O_CLOEXEC);
389 if (IS_ERR(file)) {
390 ret = PTR_ERR(file);
391 goto out_put_unused_fd;
392 }
393
394 handlereq.fd = fd;
395 if (copy_to_user(ip, &handlereq, sizeof(handlereq))) {
396 /*
397 * fput() will trigger the release() callback, so do not go onto
398 * the regular error cleanup path here.
399 */
400 fput(file);
401 put_unused_fd(fd);
402 return -EFAULT;
403 }
404
405 fd_install(fd, file);
406
407 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
408 lh->num_descs);
409
410 return 0;
411
412out_put_unused_fd:
413 put_unused_fd(fd);
414out_free_lh:
415 linehandle_free(lh);
416 return ret;
417}
418#endif /* CONFIG_GPIO_CDEV_V1 */
419
420/**
421 * struct line - contains the state of a requested line
422 * @node: to store the object in supinfo_tree if supplemental
423 * @desc: the GPIO descriptor for this line.
424 * @req: the corresponding line request
425 * @irq: the interrupt triggered in response to events on this GPIO
426 * @edflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or
427 * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied
428 * @timestamp_ns: cache for the timestamp storing it between hardirq and
429 * IRQ thread, used to bring the timestamp close to the actual event
430 * @req_seqno: the seqno for the current edge event in the sequence of
431 * events for the corresponding line request. This is drawn from the @req.
432 * @line_seqno: the seqno for the current edge event in the sequence of
433 * events for this line.
434 * @work: the worker that implements software debouncing
435 * @debounce_period_us: the debounce period in microseconds
436 * @sw_debounced: flag indicating if the software debouncer is active
437 * @level: the current debounced physical level of the line
438 * @hdesc: the Hardware Timestamp Engine (HTE) descriptor
439 * @raw_level: the line level at the time of event
440 * @total_discard_seq: the running counter of the discarded events
441 * @last_seqno: the last sequence number before debounce period expires
442 */
443struct line {
444 struct rb_node node;
445 struct gpio_desc *desc;
446 /*
447 * -- edge detector specific fields --
448 */
449 struct linereq *req;
450 unsigned int irq;
451 /*
452 * The flags for the active edge detector configuration.
453 *
454 * edflags is set by linereq_create(), linereq_free(), and
455 * linereq_set_config_unlocked(), which are themselves mutually
456 * exclusive, and is accessed by edge_irq_thread(),
457 * process_hw_ts_thread() and debounce_work_func(),
458 * which can all live with a slightly stale value.
459 */
460 u64 edflags;
461 /*
462 * timestamp_ns and req_seqno are accessed only by
463 * edge_irq_handler() and edge_irq_thread(), which are themselves
464 * mutually exclusive, so no additional protection is necessary.
465 */
466 u64 timestamp_ns;
467 u32 req_seqno;
468 /*
469 * line_seqno is accessed by either edge_irq_thread() or
470 * debounce_work_func(), which are themselves mutually exclusive,
471 * so no additional protection is necessary.
472 */
473 u32 line_seqno;
474 /*
475 * -- debouncer specific fields --
476 */
477 struct delayed_work work;
478 /*
479 * debounce_period_us is accessed by debounce_irq_handler() and
480 * process_hw_ts() which are disabled when modified by
481 * debounce_setup(), edge_detector_setup() or edge_detector_stop()
482 * or can live with a stale version when updated by
483 * edge_detector_update().
484 * The modifying functions are themselves mutually exclusive.
485 */
486 unsigned int debounce_period_us;
487 /*
488 * sw_debounce is accessed by linereq_set_config(), which is the
489 * only setter, and linereq_get_values(), which can live with a
490 * slightly stale value.
491 */
492 unsigned int sw_debounced;
493 /*
494 * level is accessed by debounce_work_func(), which is the only
495 * setter, and linereq_get_values() which can live with a slightly
496 * stale value.
497 */
498 unsigned int level;
499#ifdef CONFIG_HTE
500 struct hte_ts_desc hdesc;
501 /*
502 * HTE provider sets line level at the time of event. The valid
503 * value is 0 or 1 and negative value for an error.
504 */
505 int raw_level;
506 /*
507 * when sw_debounce is set on HTE enabled line, this is running
508 * counter of the discarded events.
509 */
510 u32 total_discard_seq;
511 /*
512 * when sw_debounce is set on HTE enabled line, this variable records
513 * last sequence number before debounce period expires.
514 */
515 u32 last_seqno;
516#endif /* CONFIG_HTE */
517};
518
519/*
520 * a rbtree of the struct lines containing supplemental info.
521 * Used to populate gpio_v2_line_info with cdev specific fields not contained
522 * in the struct gpio_desc.
523 * A line is determined to contain supplemental information by
524 * line_has_supinfo().
525 */
526static struct rb_root supinfo_tree = RB_ROOT;
527/* covers supinfo_tree */
528static DEFINE_SPINLOCK(supinfo_lock);
529
530/**
531 * struct linereq - contains the state of a userspace line request
532 * @gdev: the GPIO device the line request pertains to
533 * @label: consumer label used to tag GPIO descriptors
534 * @num_lines: the number of lines in the lines array
535 * @wait: wait queue that handles blocking reads of events
536 * @device_unregistered_nb: notifier block for receiving gdev unregister events
537 * @event_buffer_size: the number of elements allocated in @events
538 * @events: KFIFO for the GPIO events
539 * @seqno: the sequence number for edge events generated on all lines in
540 * this line request. Note that this is not used when @num_lines is 1, as
541 * the line_seqno is then the same and is cheaper to calculate.
542 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency
543 * of configuration, particularly multi-step accesses to desc flags and
544 * changes to supinfo status.
545 * @lines: the lines held by this line request, with @num_lines elements.
546 */
547struct linereq {
548 struct gpio_device *gdev;
549 const char *label;
550 u32 num_lines;
551 wait_queue_head_t wait;
552 struct notifier_block device_unregistered_nb;
553 u32 event_buffer_size;
554 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
555 atomic_t seqno;
556 struct mutex config_mutex;
557 struct line lines[] __counted_by(num_lines);
558};
559
560static void supinfo_insert(struct line *line)
561{
562 struct rb_node **new = &(supinfo_tree.rb_node), *parent = NULL;
563 struct line *entry;
564
565 guard(spinlock)(&supinfo_lock);
566
567 while (*new) {
568 entry = container_of(*new, struct line, node);
569
570 parent = *new;
571 if (line->desc < entry->desc) {
572 new = &((*new)->rb_left);
573 } else if (line->desc > entry->desc) {
574 new = &((*new)->rb_right);
575 } else {
576 /* this should never happen */
577 WARN(1, "duplicate line inserted");
578 return;
579 }
580 }
581
582 rb_link_node(&line->node, parent, new);
583 rb_insert_color(&line->node, &supinfo_tree);
584}
585
586static void supinfo_erase(struct line *line)
587{
588 guard(spinlock)(&supinfo_lock);
589
590 rb_erase(&line->node, &supinfo_tree);
591}
592
593static struct line *supinfo_find(struct gpio_desc *desc)
594{
595 struct rb_node *node = supinfo_tree.rb_node;
596 struct line *line;
597
598 while (node) {
599 line = container_of(node, struct line, node);
600 if (desc < line->desc)
601 node = node->rb_left;
602 else if (desc > line->desc)
603 node = node->rb_right;
604 else
605 return line;
606 }
607 return NULL;
608}
609
610static void supinfo_to_lineinfo(struct gpio_desc *desc,
611 struct gpio_v2_line_info *info)
612{
613 struct gpio_v2_line_attribute *attr;
614 struct line *line;
615
616 guard(spinlock)(&supinfo_lock);
617
618 line = supinfo_find(desc);
619 if (!line)
620 return;
621
622 attr = &info->attrs[info->num_attrs];
623 attr->id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
624 attr->debounce_period_us = READ_ONCE(line->debounce_period_us);
625 info->num_attrs++;
626}
627
628static inline bool line_has_supinfo(struct line *line)
629{
630 return READ_ONCE(line->debounce_period_us);
631}
632
633/*
634 * Checks line_has_supinfo() before and after the change to avoid unnecessary
635 * supinfo_tree access.
636 * Called indirectly by linereq_create() or linereq_set_config() so line
637 * is already protected from concurrent changes.
638 */
639static void line_set_debounce_period(struct line *line,
640 unsigned int debounce_period_us)
641{
642 bool was_suppl = line_has_supinfo(line);
643
644 WRITE_ONCE(line->debounce_period_us, debounce_period_us);
645
646 /* if supinfo status is unchanged then we're done */
647 if (line_has_supinfo(line) == was_suppl)
648 return;
649
650 /* supinfo status has changed, so update the tree */
651 if (was_suppl)
652 supinfo_erase(line);
653 else
654 supinfo_insert(line);
655}
656
657#define GPIO_V2_LINE_BIAS_FLAGS \
658 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \
659 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \
660 GPIO_V2_LINE_FLAG_BIAS_DISABLED)
661
662#define GPIO_V2_LINE_DIRECTION_FLAGS \
663 (GPIO_V2_LINE_FLAG_INPUT | \
664 GPIO_V2_LINE_FLAG_OUTPUT)
665
666#define GPIO_V2_LINE_DRIVE_FLAGS \
667 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \
668 GPIO_V2_LINE_FLAG_OPEN_SOURCE)
669
670#define GPIO_V2_LINE_EDGE_FLAGS \
671 (GPIO_V2_LINE_FLAG_EDGE_RISING | \
672 GPIO_V2_LINE_FLAG_EDGE_FALLING)
673
674#define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS
675
676#define GPIO_V2_LINE_VALID_FLAGS \
677 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
678 GPIO_V2_LINE_DIRECTION_FLAGS | \
679 GPIO_V2_LINE_DRIVE_FLAGS | \
680 GPIO_V2_LINE_EDGE_FLAGS | \
681 GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \
682 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
683 GPIO_V2_LINE_BIAS_FLAGS)
684
685/* subset of flags relevant for edge detector configuration */
686#define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \
687 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
688 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
689 GPIO_V2_LINE_EDGE_FLAGS)
690
691static int linereq_unregistered_notify(struct notifier_block *nb,
692 unsigned long action, void *data)
693{
694 struct linereq *lr = container_of(nb, struct linereq,
695 device_unregistered_nb);
696
697 wake_up_poll(&lr->wait, EPOLLIN | EPOLLERR);
698
699 return NOTIFY_OK;
700}
701
702static void linereq_put_event(struct linereq *lr,
703 struct gpio_v2_line_event *le)
704{
705 bool overflow = false;
706
707 scoped_guard(spinlock, &lr->wait.lock) {
708 if (kfifo_is_full(&lr->events)) {
709 overflow = true;
710 kfifo_skip(&lr->events);
711 }
712 kfifo_in(&lr->events, le, 1);
713 }
714 if (!overflow)
715 wake_up_poll(&lr->wait, EPOLLIN);
716 else
717 pr_debug_ratelimited("event FIFO is full - event dropped\n");
718}
719
720static u64 line_event_timestamp(struct line *line)
721{
722 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags))
723 return ktime_get_real_ns();
724 else if (IS_ENABLED(CONFIG_HTE) &&
725 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))
726 return line->timestamp_ns;
727
728 return ktime_get_ns();
729}
730
731static u32 line_event_id(int level)
732{
733 return level ? GPIO_V2_LINE_EVENT_RISING_EDGE :
734 GPIO_V2_LINE_EVENT_FALLING_EDGE;
735}
736
737#ifdef CONFIG_HTE
738
739static enum hte_return process_hw_ts_thread(void *p)
740{
741 struct line *line;
742 struct linereq *lr;
743 struct gpio_v2_line_event le;
744 u64 edflags;
745 int level;
746
747 if (!p)
748 return HTE_CB_HANDLED;
749
750 line = p;
751 lr = line->req;
752
753 memset(&le, 0, sizeof(le));
754
755 le.timestamp_ns = line->timestamp_ns;
756 edflags = READ_ONCE(line->edflags);
757
758 switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) {
759 case GPIO_V2_LINE_FLAG_EDGE_BOTH:
760 level = (line->raw_level >= 0) ?
761 line->raw_level :
762 gpiod_get_raw_value_cansleep(line->desc);
763
764 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
765 level = !level;
766
767 le.id = line_event_id(level);
768 break;
769 case GPIO_V2_LINE_FLAG_EDGE_RISING:
770 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
771 break;
772 case GPIO_V2_LINE_FLAG_EDGE_FALLING:
773 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
774 break;
775 default:
776 return HTE_CB_HANDLED;
777 }
778 le.line_seqno = line->line_seqno;
779 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
780 le.offset = gpio_chip_hwgpio(line->desc);
781
782 linereq_put_event(lr, &le);
783
784 return HTE_CB_HANDLED;
785}
786
787static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p)
788{
789 struct line *line;
790 struct linereq *lr;
791 int diff_seqno = 0;
792
793 if (!ts || !p)
794 return HTE_CB_HANDLED;
795
796 line = p;
797 line->timestamp_ns = ts->tsc;
798 line->raw_level = ts->raw_level;
799 lr = line->req;
800
801 if (READ_ONCE(line->sw_debounced)) {
802 line->total_discard_seq++;
803 line->last_seqno = ts->seq;
804 mod_delayed_work(system_wq, &line->work,
805 usecs_to_jiffies(READ_ONCE(line->debounce_period_us)));
806 } else {
807 if (unlikely(ts->seq < line->line_seqno))
808 return HTE_CB_HANDLED;
809
810 diff_seqno = ts->seq - line->line_seqno;
811 line->line_seqno = ts->seq;
812 if (lr->num_lines != 1)
813 line->req_seqno = atomic_add_return(diff_seqno,
814 &lr->seqno);
815
816 return HTE_RUN_SECOND_CB;
817 }
818
819 return HTE_CB_HANDLED;
820}
821
822static int hte_edge_setup(struct line *line, u64 eflags)
823{
824 int ret;
825 unsigned long flags = 0;
826 struct hte_ts_desc *hdesc = &line->hdesc;
827
828 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
829 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
830 HTE_FALLING_EDGE_TS :
831 HTE_RISING_EDGE_TS;
832 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
833 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
834 HTE_RISING_EDGE_TS :
835 HTE_FALLING_EDGE_TS;
836
837 line->total_discard_seq = 0;
838
839 hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL,
840 line->desc);
841
842 ret = hte_ts_get(NULL, hdesc, 0);
843 if (ret)
844 return ret;
845
846 return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread,
847 line);
848}
849
850#else
851
852static int hte_edge_setup(struct line *line, u64 eflags)
853{
854 return 0;
855}
856#endif /* CONFIG_HTE */
857
858static irqreturn_t edge_irq_thread(int irq, void *p)
859{
860 struct line *line = p;
861 struct linereq *lr = line->req;
862 struct gpio_v2_line_event le;
863
864 /* Do not leak kernel stack to userspace */
865 memset(&le, 0, sizeof(le));
866
867 if (line->timestamp_ns) {
868 le.timestamp_ns = line->timestamp_ns;
869 } else {
870 /*
871 * We may be running from a nested threaded interrupt in
872 * which case we didn't get the timestamp from
873 * edge_irq_handler().
874 */
875 le.timestamp_ns = line_event_timestamp(line);
876 if (lr->num_lines != 1)
877 line->req_seqno = atomic_inc_return(&lr->seqno);
878 }
879 line->timestamp_ns = 0;
880
881 switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) {
882 case GPIO_V2_LINE_FLAG_EDGE_BOTH:
883 le.id = line_event_id(gpiod_get_value_cansleep(line->desc));
884 break;
885 case GPIO_V2_LINE_FLAG_EDGE_RISING:
886 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
887 break;
888 case GPIO_V2_LINE_FLAG_EDGE_FALLING:
889 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
890 break;
891 default:
892 return IRQ_NONE;
893 }
894 line->line_seqno++;
895 le.line_seqno = line->line_seqno;
896 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
897 le.offset = gpio_chip_hwgpio(line->desc);
898
899 linereq_put_event(lr, &le);
900
901 return IRQ_HANDLED;
902}
903
904static irqreturn_t edge_irq_handler(int irq, void *p)
905{
906 struct line *line = p;
907 struct linereq *lr = line->req;
908
909 /*
910 * Just store the timestamp in hardirq context so we get it as
911 * close in time as possible to the actual event.
912 */
913 line->timestamp_ns = line_event_timestamp(line);
914
915 if (lr->num_lines != 1)
916 line->req_seqno = atomic_inc_return(&lr->seqno);
917
918 return IRQ_WAKE_THREAD;
919}
920
921/*
922 * returns the current debounced logical value.
923 */
924static bool debounced_value(struct line *line)
925{
926 bool value;
927
928 /*
929 * minor race - debouncer may be stopped here, so edge_detector_stop()
930 * must leave the value unchanged so the following will read the level
931 * from when the debouncer was last running.
932 */
933 value = READ_ONCE(line->level);
934
935 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
936 value = !value;
937
938 return value;
939}
940
941static irqreturn_t debounce_irq_handler(int irq, void *p)
942{
943 struct line *line = p;
944
945 mod_delayed_work(system_wq, &line->work,
946 usecs_to_jiffies(READ_ONCE(line->debounce_period_us)));
947
948 return IRQ_HANDLED;
949}
950
951static void debounce_work_func(struct work_struct *work)
952{
953 struct gpio_v2_line_event le;
954 struct line *line = container_of(work, struct line, work.work);
955 struct linereq *lr;
956 u64 eflags, edflags = READ_ONCE(line->edflags);
957 int level = -1;
958#ifdef CONFIG_HTE
959 int diff_seqno;
960
961 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
962 level = line->raw_level;
963#endif
964 if (level < 0)
965 level = gpiod_get_raw_value_cansleep(line->desc);
966 if (level < 0) {
967 pr_debug_ratelimited("debouncer failed to read line value\n");
968 return;
969 }
970
971 if (READ_ONCE(line->level) == level)
972 return;
973
974 WRITE_ONCE(line->level, level);
975
976 /* -- edge detection -- */
977 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
978 if (!eflags)
979 return;
980
981 /* switch from physical level to logical - if they differ */
982 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
983 level = !level;
984
985 /* ignore edges that are not being monitored */
986 if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) ||
987 ((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level))
988 return;
989
990 /* Do not leak kernel stack to userspace */
991 memset(&le, 0, sizeof(le));
992
993 lr = line->req;
994 le.timestamp_ns = line_event_timestamp(line);
995 le.offset = gpio_chip_hwgpio(line->desc);
996#ifdef CONFIG_HTE
997 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) {
998 /* discard events except the last one */
999 line->total_discard_seq -= 1;
1000 diff_seqno = line->last_seqno - line->total_discard_seq -
1001 line->line_seqno;
1002 line->line_seqno = line->last_seqno - line->total_discard_seq;
1003 le.line_seqno = line->line_seqno;
1004 le.seqno = (lr->num_lines == 1) ?
1005 le.line_seqno : atomic_add_return(diff_seqno, &lr->seqno);
1006 } else
1007#endif /* CONFIG_HTE */
1008 {
1009 line->line_seqno++;
1010 le.line_seqno = line->line_seqno;
1011 le.seqno = (lr->num_lines == 1) ?
1012 le.line_seqno : atomic_inc_return(&lr->seqno);
1013 }
1014
1015 le.id = line_event_id(level);
1016
1017 linereq_put_event(lr, &le);
1018}
1019
1020static int debounce_setup(struct line *line, unsigned int debounce_period_us)
1021{
1022 unsigned long irqflags;
1023 int ret, level, irq;
1024
1025 /* try hardware */
1026 ret = gpiod_set_debounce(line->desc, debounce_period_us);
1027 if (!ret) {
1028 line_set_debounce_period(line, debounce_period_us);
1029 return ret;
1030 }
1031 if (ret != -ENOTSUPP)
1032 return ret;
1033
1034 if (debounce_period_us) {
1035 /* setup software debounce */
1036 level = gpiod_get_raw_value_cansleep(line->desc);
1037 if (level < 0)
1038 return level;
1039
1040 if (!(IS_ENABLED(CONFIG_HTE) &&
1041 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) {
1042 irq = gpiod_to_irq(line->desc);
1043 if (irq < 0)
1044 return -ENXIO;
1045
1046 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
1047 ret = request_irq(irq, debounce_irq_handler, irqflags,
1048 line->req->label, line);
1049 if (ret)
1050 return ret;
1051 line->irq = irq;
1052 } else {
1053 ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH);
1054 if (ret)
1055 return ret;
1056 }
1057
1058 WRITE_ONCE(line->level, level);
1059 WRITE_ONCE(line->sw_debounced, 1);
1060 }
1061 return 0;
1062}
1063
1064static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc,
1065 unsigned int line_idx)
1066{
1067 unsigned int i;
1068 u64 mask = BIT_ULL(line_idx);
1069
1070 for (i = 0; i < lc->num_attrs; i++) {
1071 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
1072 (lc->attrs[i].mask & mask))
1073 return true;
1074 }
1075 return false;
1076}
1077
1078static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
1079 unsigned int line_idx)
1080{
1081 unsigned int i;
1082 u64 mask = BIT_ULL(line_idx);
1083
1084 for (i = 0; i < lc->num_attrs; i++) {
1085 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
1086 (lc->attrs[i].mask & mask))
1087 return lc->attrs[i].attr.debounce_period_us;
1088 }
1089 return 0;
1090}
1091
1092static void edge_detector_stop(struct line *line)
1093{
1094 if (line->irq) {
1095 free_irq(line->irq, line);
1096 line->irq = 0;
1097 }
1098
1099#ifdef CONFIG_HTE
1100 if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
1101 hte_ts_put(&line->hdesc);
1102#endif
1103
1104 cancel_delayed_work_sync(&line->work);
1105 WRITE_ONCE(line->sw_debounced, 0);
1106 WRITE_ONCE(line->edflags, 0);
1107 line_set_debounce_period(line, 0);
1108 /* do not change line->level - see comment in debounced_value() */
1109}
1110
1111static int edge_detector_setup(struct line *line,
1112 struct gpio_v2_line_config *lc,
1113 unsigned int line_idx, u64 edflags)
1114{
1115 u32 debounce_period_us;
1116 unsigned long irqflags = 0;
1117 u64 eflags;
1118 int irq, ret;
1119
1120 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
1121 if (eflags && !kfifo_initialized(&line->req->events)) {
1122 ret = kfifo_alloc(&line->req->events,
1123 line->req->event_buffer_size, GFP_KERNEL);
1124 if (ret)
1125 return ret;
1126 }
1127 if (gpio_v2_line_config_debounced(lc, line_idx)) {
1128 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
1129 ret = debounce_setup(line, debounce_period_us);
1130 if (ret)
1131 return ret;
1132 line_set_debounce_period(line, debounce_period_us);
1133 }
1134
1135 /* detection disabled or sw debouncer will provide edge detection */
1136 if (!eflags || READ_ONCE(line->sw_debounced))
1137 return 0;
1138
1139 if (IS_ENABLED(CONFIG_HTE) &&
1140 (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1141 return hte_edge_setup(line, edflags);
1142
1143 irq = gpiod_to_irq(line->desc);
1144 if (irq < 0)
1145 return -ENXIO;
1146
1147 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
1148 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
1149 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
1150 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
1151 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
1152 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
1153 irqflags |= IRQF_ONESHOT;
1154
1155 /* Request a thread to read the events */
1156 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
1157 irqflags, line->req->label, line);
1158 if (ret)
1159 return ret;
1160
1161 line->irq = irq;
1162 return 0;
1163}
1164
1165static int edge_detector_update(struct line *line,
1166 struct gpio_v2_line_config *lc,
1167 unsigned int line_idx, u64 edflags)
1168{
1169 u64 active_edflags = READ_ONCE(line->edflags);
1170 unsigned int debounce_period_us =
1171 gpio_v2_line_config_debounce_period(lc, line_idx);
1172
1173 if ((active_edflags == edflags) &&
1174 (READ_ONCE(line->debounce_period_us) == debounce_period_us))
1175 return 0;
1176
1177 /* sw debounced and still will be...*/
1178 if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
1179 line_set_debounce_period(line, debounce_period_us);
1180 return 0;
1181 }
1182
1183 /* reconfiguring edge detection or sw debounce being disabled */
1184 if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
1185 (active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) ||
1186 (!debounce_period_us && READ_ONCE(line->sw_debounced)))
1187 edge_detector_stop(line);
1188
1189 return edge_detector_setup(line, lc, line_idx, edflags);
1190}
1191
1192static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
1193 unsigned int line_idx)
1194{
1195 unsigned int i;
1196 u64 mask = BIT_ULL(line_idx);
1197
1198 for (i = 0; i < lc->num_attrs; i++) {
1199 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) &&
1200 (lc->attrs[i].mask & mask))
1201 return lc->attrs[i].attr.flags;
1202 }
1203 return lc->flags;
1204}
1205
1206static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc,
1207 unsigned int line_idx)
1208{
1209 unsigned int i;
1210 u64 mask = BIT_ULL(line_idx);
1211
1212 for (i = 0; i < lc->num_attrs; i++) {
1213 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) &&
1214 (lc->attrs[i].mask & mask))
1215 return !!(lc->attrs[i].attr.values & mask);
1216 }
1217 return 0;
1218}
1219
1220static int gpio_v2_line_flags_validate(u64 flags)
1221{
1222 /* Return an error if an unknown flag is set */
1223 if (flags & ~GPIO_V2_LINE_VALID_FLAGS)
1224 return -EINVAL;
1225
1226 if (!IS_ENABLED(CONFIG_HTE) &&
1227 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1228 return -EOPNOTSUPP;
1229
1230 /*
1231 * Do not allow both INPUT and OUTPUT flags to be set as they are
1232 * contradictory.
1233 */
1234 if ((flags & GPIO_V2_LINE_FLAG_INPUT) &&
1235 (flags & GPIO_V2_LINE_FLAG_OUTPUT))
1236 return -EINVAL;
1237
1238 /* Only allow one event clock source */
1239 if (IS_ENABLED(CONFIG_HTE) &&
1240 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME) &&
1241 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1242 return -EINVAL;
1243
1244 /* Edge detection requires explicit input. */
1245 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) &&
1246 !(flags & GPIO_V2_LINE_FLAG_INPUT))
1247 return -EINVAL;
1248
1249 /*
1250 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single
1251 * request. If the hardware actually supports enabling both at the
1252 * same time the electrical result would be disastrous.
1253 */
1254 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) &&
1255 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE))
1256 return -EINVAL;
1257
1258 /* Drive requires explicit output direction. */
1259 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) &&
1260 !(flags & GPIO_V2_LINE_FLAG_OUTPUT))
1261 return -EINVAL;
1262
1263 /* Bias requires explicit direction. */
1264 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) &&
1265 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
1266 return -EINVAL;
1267
1268 /* Only one bias flag can be set. */
1269 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) &&
1270 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN |
1271 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) ||
1272 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) &&
1273 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)))
1274 return -EINVAL;
1275
1276 return 0;
1277}
1278
1279static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
1280 unsigned int num_lines)
1281{
1282 unsigned int i;
1283 u64 flags;
1284 int ret;
1285
1286 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX)
1287 return -EINVAL;
1288
1289 if (memchr_inv(lc->padding, 0, sizeof(lc->padding)))
1290 return -EINVAL;
1291
1292 for (i = 0; i < num_lines; i++) {
1293 flags = gpio_v2_line_config_flags(lc, i);
1294 ret = gpio_v2_line_flags_validate(flags);
1295 if (ret)
1296 return ret;
1297
1298 /* debounce requires explicit input */
1299 if (gpio_v2_line_config_debounced(lc, i) &&
1300 !(flags & GPIO_V2_LINE_FLAG_INPUT))
1301 return -EINVAL;
1302 }
1303 return 0;
1304}
1305
1306static void gpio_v2_line_config_flags_to_desc_flags(u64 flags,
1307 unsigned long *flagsp)
1308{
1309 assign_bit(FLAG_ACTIVE_LOW, flagsp,
1310 flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW);
1311
1312 if (flags & GPIO_V2_LINE_FLAG_OUTPUT)
1313 set_bit(FLAG_IS_OUT, flagsp);
1314 else if (flags & GPIO_V2_LINE_FLAG_INPUT)
1315 clear_bit(FLAG_IS_OUT, flagsp);
1316
1317 assign_bit(FLAG_EDGE_RISING, flagsp,
1318 flags & GPIO_V2_LINE_FLAG_EDGE_RISING);
1319 assign_bit(FLAG_EDGE_FALLING, flagsp,
1320 flags & GPIO_V2_LINE_FLAG_EDGE_FALLING);
1321
1322 assign_bit(FLAG_OPEN_DRAIN, flagsp,
1323 flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN);
1324 assign_bit(FLAG_OPEN_SOURCE, flagsp,
1325 flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE);
1326
1327 assign_bit(FLAG_PULL_UP, flagsp,
1328 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP);
1329 assign_bit(FLAG_PULL_DOWN, flagsp,
1330 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN);
1331 assign_bit(FLAG_BIAS_DISABLE, flagsp,
1332 flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED);
1333
1334 assign_bit(FLAG_EVENT_CLOCK_REALTIME, flagsp,
1335 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME);
1336 assign_bit(FLAG_EVENT_CLOCK_HTE, flagsp,
1337 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE);
1338}
1339
1340static long linereq_get_values(struct linereq *lr, void __user *ip)
1341{
1342 struct gpio_v2_line_values lv;
1343 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1344 struct gpio_desc **descs;
1345 unsigned int i, didx, num_get;
1346 bool val;
1347 int ret;
1348
1349 /* NOTE: It's ok to read values of output lines. */
1350 if (copy_from_user(&lv, ip, sizeof(lv)))
1351 return -EFAULT;
1352
1353 /*
1354 * gpiod_get_array_value_complex() requires compacted desc and val
1355 * arrays, rather than the sparse ones in lv.
1356 * Calculation of num_get and construction of the desc array is
1357 * optimized to avoid allocation for the desc array for the common
1358 * num_get == 1 case.
1359 */
1360 /* scan requested lines to calculate the subset to get */
1361 for (num_get = 0, i = 0; i < lr->num_lines; i++) {
1362 if (lv.mask & BIT_ULL(i)) {
1363 num_get++;
1364 /* capture desc for the num_get == 1 case */
1365 descs = &lr->lines[i].desc;
1366 }
1367 }
1368
1369 if (num_get == 0)
1370 return -EINVAL;
1371
1372 if (num_get != 1) {
1373 /* build compacted desc array */
1374 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL);
1375 if (!descs)
1376 return -ENOMEM;
1377 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1378 if (lv.mask & BIT_ULL(i)) {
1379 descs[didx] = lr->lines[i].desc;
1380 didx++;
1381 }
1382 }
1383 }
1384 ret = gpiod_get_array_value_complex(false, true, num_get,
1385 descs, NULL, vals);
1386
1387 if (num_get != 1)
1388 kfree(descs);
1389 if (ret)
1390 return ret;
1391
1392 lv.bits = 0;
1393 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1394 /* unpack compacted vals for the response */
1395 if (lv.mask & BIT_ULL(i)) {
1396 if (lr->lines[i].sw_debounced)
1397 val = debounced_value(&lr->lines[i]);
1398 else
1399 val = test_bit(didx, vals);
1400 if (val)
1401 lv.bits |= BIT_ULL(i);
1402 didx++;
1403 }
1404 }
1405
1406 if (copy_to_user(ip, &lv, sizeof(lv)))
1407 return -EFAULT;
1408
1409 return 0;
1410}
1411
1412static long linereq_set_values(struct linereq *lr, void __user *ip)
1413{
1414 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1415 struct gpio_v2_line_values lv;
1416 struct gpio_desc **descs;
1417 unsigned int i, didx, num_set;
1418 int ret;
1419
1420 if (copy_from_user(&lv, ip, sizeof(lv)))
1421 return -EFAULT;
1422
1423 guard(mutex)(&lr->config_mutex);
1424
1425 /*
1426 * gpiod_set_array_value_complex() requires compacted desc and val
1427 * arrays, rather than the sparse ones in lv.
1428 * Calculation of num_set and construction of the descs and vals arrays
1429 * is optimized to minimize scanning the lv->mask, and to avoid
1430 * allocation for the desc array for the common num_set == 1 case.
1431 */
1432 bitmap_zero(vals, GPIO_V2_LINES_MAX);
1433 /* scan requested lines to determine the subset to be set */
1434 for (num_set = 0, i = 0; i < lr->num_lines; i++) {
1435 if (lv.mask & BIT_ULL(i)) {
1436 /* setting inputs is not allowed */
1437 if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
1438 return -EPERM;
1439 /* add to compacted values */
1440 if (lv.bits & BIT_ULL(i))
1441 __set_bit(num_set, vals);
1442 num_set++;
1443 /* capture desc for the num_set == 1 case */
1444 descs = &lr->lines[i].desc;
1445 }
1446 }
1447 if (num_set == 0)
1448 return -EINVAL;
1449
1450 if (num_set != 1) {
1451 /* build compacted desc array */
1452 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);
1453 if (!descs)
1454 return -ENOMEM;
1455 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1456 if (lv.mask & BIT_ULL(i)) {
1457 descs[didx] = lr->lines[i].desc;
1458 didx++;
1459 }
1460 }
1461 }
1462 ret = gpiod_set_array_value_complex(false, true, num_set,
1463 descs, NULL, vals);
1464
1465 if (num_set != 1)
1466 kfree(descs);
1467 return ret;
1468}
1469
1470static long linereq_set_config(struct linereq *lr, void __user *ip)
1471{
1472 struct gpio_v2_line_config lc;
1473 struct gpio_desc *desc;
1474 struct line *line;
1475 unsigned int i;
1476 u64 flags, edflags;
1477 int ret;
1478
1479 if (copy_from_user(&lc, ip, sizeof(lc)))
1480 return -EFAULT;
1481
1482 ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
1483 if (ret)
1484 return ret;
1485
1486 guard(mutex)(&lr->config_mutex);
1487
1488 for (i = 0; i < lr->num_lines; i++) {
1489 line = &lr->lines[i];
1490 desc = lr->lines[i].desc;
1491 flags = gpio_v2_line_config_flags(&lc, i);
1492 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1493 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
1494 /*
1495 * Lines have to be requested explicitly for input
1496 * or output, else the line will be treated "as is".
1497 */
1498 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1499 int val = gpio_v2_line_config_output_value(&lc, i);
1500
1501 edge_detector_stop(line);
1502 ret = gpiod_direction_output(desc, val);
1503 if (ret)
1504 return ret;
1505 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1506 ret = gpiod_direction_input(desc);
1507 if (ret)
1508 return ret;
1509
1510 ret = edge_detector_update(line, &lc, i, edflags);
1511 if (ret)
1512 return ret;
1513 }
1514
1515 WRITE_ONCE(line->edflags, edflags);
1516
1517 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
1518 }
1519 return 0;
1520}
1521
1522static long linereq_ioctl(struct file *file, unsigned int cmd,
1523 unsigned long arg)
1524{
1525 struct linereq *lr = file->private_data;
1526 void __user *ip = (void __user *)arg;
1527
1528 guard(rwsem_read)(&lr->gdev->sem);
1529
1530 if (!lr->gdev->chip)
1531 return -ENODEV;
1532
1533 switch (cmd) {
1534 case GPIO_V2_LINE_GET_VALUES_IOCTL:
1535 return linereq_get_values(lr, ip);
1536 case GPIO_V2_LINE_SET_VALUES_IOCTL:
1537 return linereq_set_values(lr, ip);
1538 case GPIO_V2_LINE_SET_CONFIG_IOCTL:
1539 return linereq_set_config(lr, ip);
1540 default:
1541 return -EINVAL;
1542 }
1543}
1544
1545#ifdef CONFIG_COMPAT
1546static long linereq_ioctl_compat(struct file *file, unsigned int cmd,
1547 unsigned long arg)
1548{
1549 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1550}
1551#endif
1552
1553static __poll_t linereq_poll(struct file *file,
1554 struct poll_table_struct *wait)
1555{
1556 struct linereq *lr = file->private_data;
1557 __poll_t events = 0;
1558
1559 guard(rwsem_read)(&lr->gdev->sem);
1560
1561 if (!lr->gdev->chip)
1562 return EPOLLHUP | EPOLLERR;
1563
1564 poll_wait(file, &lr->wait, wait);
1565
1566 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events,
1567 &lr->wait.lock))
1568 events = EPOLLIN | EPOLLRDNORM;
1569
1570 return events;
1571}
1572
1573static ssize_t linereq_read(struct file *file, char __user *buf,
1574 size_t count, loff_t *f_ps)
1575{
1576 struct linereq *lr = file->private_data;
1577 struct gpio_v2_line_event le;
1578 ssize_t bytes_read = 0;
1579 int ret;
1580
1581 guard(rwsem_read)(&lr->gdev->sem);
1582
1583 if (!lr->gdev->chip)
1584 return -ENODEV;
1585
1586 if (count < sizeof(le))
1587 return -EINVAL;
1588
1589 do {
1590 scoped_guard(spinlock, &lr->wait.lock) {
1591 if (kfifo_is_empty(&lr->events)) {
1592 if (bytes_read)
1593 return bytes_read;
1594
1595 if (file->f_flags & O_NONBLOCK)
1596 return -EAGAIN;
1597
1598 ret = wait_event_interruptible_locked(lr->wait,
1599 !kfifo_is_empty(&lr->events));
1600 if (ret)
1601 return ret;
1602 }
1603
1604 ret = kfifo_out(&lr->events, &le, 1);
1605 }
1606 if (ret != 1) {
1607 /*
1608 * This should never happen - we were holding the
1609 * lock from the moment we learned the fifo is no
1610 * longer empty until now.
1611 */
1612 ret = -EIO;
1613 break;
1614 }
1615
1616 if (copy_to_user(buf + bytes_read, &le, sizeof(le)))
1617 return -EFAULT;
1618 bytes_read += sizeof(le);
1619 } while (count >= bytes_read + sizeof(le));
1620
1621 return bytes_read;
1622}
1623
1624static void linereq_free(struct linereq *lr)
1625{
1626 struct line *line;
1627 unsigned int i;
1628
1629 if (lr->device_unregistered_nb.notifier_call)
1630 blocking_notifier_chain_unregister(&lr->gdev->device_notifier,
1631 &lr->device_unregistered_nb);
1632
1633 for (i = 0; i < lr->num_lines; i++) {
1634 line = &lr->lines[i];
1635 if (!line->desc)
1636 continue;
1637
1638 edge_detector_stop(line);
1639 if (line_has_supinfo(line))
1640 supinfo_erase(line);
1641 gpiod_free(line->desc);
1642 }
1643 kfifo_free(&lr->events);
1644 kfree(lr->label);
1645 gpio_device_put(lr->gdev);
1646 kvfree(lr);
1647}
1648
1649static int linereq_release(struct inode *inode, struct file *file)
1650{
1651 struct linereq *lr = file->private_data;
1652
1653 linereq_free(lr);
1654 return 0;
1655}
1656
1657#ifdef CONFIG_PROC_FS
1658static void linereq_show_fdinfo(struct seq_file *out, struct file *file)
1659{
1660 struct linereq *lr = file->private_data;
1661 struct device *dev = &lr->gdev->dev;
1662 u16 i;
1663
1664 seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev));
1665
1666 for (i = 0; i < lr->num_lines; i++)
1667 seq_printf(out, "gpio-line:\t%d\n",
1668 gpio_chip_hwgpio(lr->lines[i].desc));
1669}
1670#endif
1671
1672static const struct file_operations line_fileops = {
1673 .release = linereq_release,
1674 .read = linereq_read,
1675 .poll = linereq_poll,
1676 .owner = THIS_MODULE,
1677 .llseek = noop_llseek,
1678 .unlocked_ioctl = linereq_ioctl,
1679#ifdef CONFIG_COMPAT
1680 .compat_ioctl = linereq_ioctl_compat,
1681#endif
1682#ifdef CONFIG_PROC_FS
1683 .show_fdinfo = linereq_show_fdinfo,
1684#endif
1685};
1686
1687static int linereq_create(struct gpio_device *gdev, void __user *ip)
1688{
1689 struct gpio_v2_line_request ulr;
1690 struct gpio_v2_line_config *lc;
1691 struct linereq *lr;
1692 struct file *file;
1693 u64 flags, edflags;
1694 unsigned int i;
1695 int fd, ret;
1696
1697 if (copy_from_user(&ulr, ip, sizeof(ulr)))
1698 return -EFAULT;
1699
1700 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
1701 return -EINVAL;
1702
1703 if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding)))
1704 return -EINVAL;
1705
1706 lc = &ulr.config;
1707 ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
1708 if (ret)
1709 return ret;
1710
1711 lr = kvzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
1712 if (!lr)
1713 return -ENOMEM;
1714 lr->num_lines = ulr.num_lines;
1715
1716 lr->gdev = gpio_device_get(gdev);
1717
1718 for (i = 0; i < ulr.num_lines; i++) {
1719 lr->lines[i].req = lr;
1720 WRITE_ONCE(lr->lines[i].sw_debounced, 0);
1721 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
1722 }
1723
1724 if (ulr.consumer[0] != '\0') {
1725 /* label is only initialized if consumer is set */
1726 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
1727 GFP_KERNEL);
1728 if (!lr->label) {
1729 ret = -ENOMEM;
1730 goto out_free_linereq;
1731 }
1732 }
1733
1734 mutex_init(&lr->config_mutex);
1735 init_waitqueue_head(&lr->wait);
1736 lr->event_buffer_size = ulr.event_buffer_size;
1737 if (lr->event_buffer_size == 0)
1738 lr->event_buffer_size = ulr.num_lines * 16;
1739 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16)
1740 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;
1741
1742 atomic_set(&lr->seqno, 0);
1743
1744 /* Request each GPIO */
1745 for (i = 0; i < ulr.num_lines; i++) {
1746 u32 offset = ulr.offsets[i];
1747 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
1748
1749 if (IS_ERR(desc)) {
1750 ret = PTR_ERR(desc);
1751 goto out_free_linereq;
1752 }
1753
1754 ret = gpiod_request_user(desc, lr->label);
1755 if (ret)
1756 goto out_free_linereq;
1757
1758 lr->lines[i].desc = desc;
1759 flags = gpio_v2_line_config_flags(lc, i);
1760 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1761
1762 ret = gpiod_set_transitory(desc, false);
1763 if (ret < 0)
1764 goto out_free_linereq;
1765
1766 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
1767 /*
1768 * Lines have to be requested explicitly for input
1769 * or output, else the line will be treated "as is".
1770 */
1771 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1772 int val = gpio_v2_line_config_output_value(lc, i);
1773
1774 ret = gpiod_direction_output(desc, val);
1775 if (ret)
1776 goto out_free_linereq;
1777 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1778 ret = gpiod_direction_input(desc);
1779 if (ret)
1780 goto out_free_linereq;
1781
1782 ret = edge_detector_setup(&lr->lines[i], lc, i,
1783 edflags);
1784 if (ret)
1785 goto out_free_linereq;
1786 }
1787
1788 lr->lines[i].edflags = edflags;
1789
1790 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
1791
1792 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
1793 offset);
1794 }
1795
1796 lr->device_unregistered_nb.notifier_call = linereq_unregistered_notify;
1797 ret = blocking_notifier_chain_register(&gdev->device_notifier,
1798 &lr->device_unregistered_nb);
1799 if (ret)
1800 goto out_free_linereq;
1801
1802 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
1803 if (fd < 0) {
1804 ret = fd;
1805 goto out_free_linereq;
1806 }
1807
1808 file = anon_inode_getfile("gpio-line", &line_fileops, lr,
1809 O_RDONLY | O_CLOEXEC);
1810 if (IS_ERR(file)) {
1811 ret = PTR_ERR(file);
1812 goto out_put_unused_fd;
1813 }
1814
1815 ulr.fd = fd;
1816 if (copy_to_user(ip, &ulr, sizeof(ulr))) {
1817 /*
1818 * fput() will trigger the release() callback, so do not go onto
1819 * the regular error cleanup path here.
1820 */
1821 fput(file);
1822 put_unused_fd(fd);
1823 return -EFAULT;
1824 }
1825
1826 fd_install(fd, file);
1827
1828 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
1829 lr->num_lines);
1830
1831 return 0;
1832
1833out_put_unused_fd:
1834 put_unused_fd(fd);
1835out_free_linereq:
1836 linereq_free(lr);
1837 return ret;
1838}
1839
1840#ifdef CONFIG_GPIO_CDEV_V1
1841
1842/*
1843 * GPIO line event management
1844 */
1845
1846/**
1847 * struct lineevent_state - contains the state of a userspace event
1848 * @gdev: the GPIO device the event pertains to
1849 * @label: consumer label used to tag descriptors
1850 * @desc: the GPIO descriptor held by this event
1851 * @eflags: the event flags this line was requested with
1852 * @irq: the interrupt that trigger in response to events on this GPIO
1853 * @wait: wait queue that handles blocking reads of events
1854 * @device_unregistered_nb: notifier block for receiving gdev unregister events
1855 * @events: KFIFO for the GPIO events
1856 * @timestamp: cache for the timestamp storing it between hardirq
1857 * and IRQ thread, used to bring the timestamp close to the actual
1858 * event
1859 */
1860struct lineevent_state {
1861 struct gpio_device *gdev;
1862 const char *label;
1863 struct gpio_desc *desc;
1864 u32 eflags;
1865 int irq;
1866 wait_queue_head_t wait;
1867 struct notifier_block device_unregistered_nb;
1868 DECLARE_KFIFO(events, struct gpioevent_data, 16);
1869 u64 timestamp;
1870};
1871
1872#define GPIOEVENT_REQUEST_VALID_FLAGS \
1873 (GPIOEVENT_REQUEST_RISING_EDGE | \
1874 GPIOEVENT_REQUEST_FALLING_EDGE)
1875
1876static __poll_t lineevent_poll(struct file *file,
1877 struct poll_table_struct *wait)
1878{
1879 struct lineevent_state *le = file->private_data;
1880 __poll_t events = 0;
1881
1882 guard(rwsem_read)(&le->gdev->sem);
1883
1884 if (!le->gdev->chip)
1885 return EPOLLHUP | EPOLLERR;
1886
1887 poll_wait(file, &le->wait, wait);
1888
1889 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
1890 events = EPOLLIN | EPOLLRDNORM;
1891
1892 return events;
1893}
1894
1895static int lineevent_unregistered_notify(struct notifier_block *nb,
1896 unsigned long action, void *data)
1897{
1898 struct lineevent_state *le = container_of(nb, struct lineevent_state,
1899 device_unregistered_nb);
1900
1901 wake_up_poll(&le->wait, EPOLLIN | EPOLLERR);
1902
1903 return NOTIFY_OK;
1904}
1905
1906struct compat_gpioeevent_data {
1907 compat_u64 timestamp;
1908 u32 id;
1909};
1910
1911static ssize_t lineevent_read(struct file *file, char __user *buf,
1912 size_t count, loff_t *f_ps)
1913{
1914 struct lineevent_state *le = file->private_data;
1915 struct gpioevent_data ge;
1916 ssize_t bytes_read = 0;
1917 ssize_t ge_size;
1918 int ret;
1919
1920 guard(rwsem_read)(&le->gdev->sem);
1921
1922 if (!le->gdev->chip)
1923 return -ENODEV;
1924
1925 /*
1926 * When compatible system call is being used the struct gpioevent_data,
1927 * in case of at least ia32, has different size due to the alignment
1928 * differences. Because we have first member 64 bits followed by one of
1929 * 32 bits there is no gap between them. The only difference is the
1930 * padding at the end of the data structure. Hence, we calculate the
1931 * actual sizeof() and pass this as an argument to copy_to_user() to
1932 * drop unneeded bytes from the output.
1933 */
1934 if (compat_need_64bit_alignment_fixup())
1935 ge_size = sizeof(struct compat_gpioeevent_data);
1936 else
1937 ge_size = sizeof(struct gpioevent_data);
1938 if (count < ge_size)
1939 return -EINVAL;
1940
1941 do {
1942 scoped_guard(spinlock, &le->wait.lock) {
1943 if (kfifo_is_empty(&le->events)) {
1944 if (bytes_read)
1945 return bytes_read;
1946
1947 if (file->f_flags & O_NONBLOCK)
1948 return -EAGAIN;
1949
1950 ret = wait_event_interruptible_locked(le->wait,
1951 !kfifo_is_empty(&le->events));
1952 if (ret)
1953 return ret;
1954 }
1955
1956 ret = kfifo_out(&le->events, &ge, 1);
1957 }
1958 if (ret != 1) {
1959 /*
1960 * This should never happen - we were holding the lock
1961 * from the moment we learned the fifo is no longer
1962 * empty until now.
1963 */
1964 ret = -EIO;
1965 break;
1966 }
1967
1968 if (copy_to_user(buf + bytes_read, &ge, ge_size))
1969 return -EFAULT;
1970 bytes_read += ge_size;
1971 } while (count >= bytes_read + ge_size);
1972
1973 return bytes_read;
1974}
1975
1976static void lineevent_free(struct lineevent_state *le)
1977{
1978 if (le->device_unregistered_nb.notifier_call)
1979 blocking_notifier_chain_unregister(&le->gdev->device_notifier,
1980 &le->device_unregistered_nb);
1981 if (le->irq)
1982 free_irq(le->irq, le);
1983 if (le->desc)
1984 gpiod_free(le->desc);
1985 kfree(le->label);
1986 gpio_device_put(le->gdev);
1987 kfree(le);
1988}
1989
1990static int lineevent_release(struct inode *inode, struct file *file)
1991{
1992 lineevent_free(file->private_data);
1993 return 0;
1994}
1995
1996static long lineevent_ioctl(struct file *file, unsigned int cmd,
1997 unsigned long arg)
1998{
1999 struct lineevent_state *le = file->private_data;
2000 void __user *ip = (void __user *)arg;
2001 struct gpiohandle_data ghd;
2002
2003 guard(rwsem_read)(&le->gdev->sem);
2004
2005 if (!le->gdev->chip)
2006 return -ENODEV;
2007
2008 /*
2009 * We can get the value for an event line but not set it,
2010 * because it is input by definition.
2011 */
2012 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
2013 int val;
2014
2015 memset(&ghd, 0, sizeof(ghd));
2016
2017 val = gpiod_get_value_cansleep(le->desc);
2018 if (val < 0)
2019 return val;
2020 ghd.values[0] = val;
2021
2022 if (copy_to_user(ip, &ghd, sizeof(ghd)))
2023 return -EFAULT;
2024
2025 return 0;
2026 }
2027 return -EINVAL;
2028}
2029
2030#ifdef CONFIG_COMPAT
2031static long lineevent_ioctl_compat(struct file *file, unsigned int cmd,
2032 unsigned long arg)
2033{
2034 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2035}
2036#endif
2037
2038static const struct file_operations lineevent_fileops = {
2039 .release = lineevent_release,
2040 .read = lineevent_read,
2041 .poll = lineevent_poll,
2042 .owner = THIS_MODULE,
2043 .llseek = noop_llseek,
2044 .unlocked_ioctl = lineevent_ioctl,
2045#ifdef CONFIG_COMPAT
2046 .compat_ioctl = lineevent_ioctl_compat,
2047#endif
2048};
2049
2050static irqreturn_t lineevent_irq_thread(int irq, void *p)
2051{
2052 struct lineevent_state *le = p;
2053 struct gpioevent_data ge;
2054 int ret;
2055
2056 /* Do not leak kernel stack to userspace */
2057 memset(&ge, 0, sizeof(ge));
2058
2059 /*
2060 * We may be running from a nested threaded interrupt in which case
2061 * we didn't get the timestamp from lineevent_irq_handler().
2062 */
2063 if (!le->timestamp)
2064 ge.timestamp = ktime_get_ns();
2065 else
2066 ge.timestamp = le->timestamp;
2067
2068 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
2069 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
2070 int level = gpiod_get_value_cansleep(le->desc);
2071
2072 if (level)
2073 /* Emit low-to-high event */
2074 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
2075 else
2076 /* Emit high-to-low event */
2077 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
2078 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
2079 /* Emit low-to-high event */
2080 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
2081 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
2082 /* Emit high-to-low event */
2083 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
2084 } else {
2085 return IRQ_NONE;
2086 }
2087
2088 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
2089 1, &le->wait.lock);
2090 if (ret)
2091 wake_up_poll(&le->wait, EPOLLIN);
2092 else
2093 pr_debug_ratelimited("event FIFO is full - event dropped\n");
2094
2095 return IRQ_HANDLED;
2096}
2097
2098static irqreturn_t lineevent_irq_handler(int irq, void *p)
2099{
2100 struct lineevent_state *le = p;
2101
2102 /*
2103 * Just store the timestamp in hardirq context so we get it as
2104 * close in time as possible to the actual event.
2105 */
2106 le->timestamp = ktime_get_ns();
2107
2108 return IRQ_WAKE_THREAD;
2109}
2110
2111static int lineevent_create(struct gpio_device *gdev, void __user *ip)
2112{
2113 struct gpioevent_request eventreq;
2114 struct lineevent_state *le;
2115 struct gpio_desc *desc;
2116 struct file *file;
2117 u32 offset;
2118 u32 lflags;
2119 u32 eflags;
2120 int fd;
2121 int ret;
2122 int irq, irqflags = 0;
2123
2124 if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
2125 return -EFAULT;
2126
2127 offset = eventreq.lineoffset;
2128 lflags = eventreq.handleflags;
2129 eflags = eventreq.eventflags;
2130
2131 desc = gpiochip_get_desc(gdev->chip, offset);
2132 if (IS_ERR(desc))
2133 return PTR_ERR(desc);
2134
2135 /* Return an error if a unknown flag is set */
2136 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
2137 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
2138 return -EINVAL;
2139
2140 /* This is just wrong: we don't look for events on output lines */
2141 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
2142 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
2143 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
2144 return -EINVAL;
2145
2146 /* Only one bias flag can be set. */
2147 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
2148 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
2149 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
2150 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
2151 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
2152 return -EINVAL;
2153
2154 le = kzalloc(sizeof(*le), GFP_KERNEL);
2155 if (!le)
2156 return -ENOMEM;
2157 le->gdev = gpio_device_get(gdev);
2158
2159 if (eventreq.consumer_label[0] != '\0') {
2160 /* label is only initialized if consumer_label is set */
2161 le->label = kstrndup(eventreq.consumer_label,
2162 sizeof(eventreq.consumer_label) - 1,
2163 GFP_KERNEL);
2164 if (!le->label) {
2165 ret = -ENOMEM;
2166 goto out_free_le;
2167 }
2168 }
2169
2170 ret = gpiod_request_user(desc, le->label);
2171 if (ret)
2172 goto out_free_le;
2173 le->desc = desc;
2174 le->eflags = eflags;
2175
2176 linehandle_flags_to_desc_flags(lflags, &desc->flags);
2177
2178 ret = gpiod_direction_input(desc);
2179 if (ret)
2180 goto out_free_le;
2181
2182 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
2183
2184 irq = gpiod_to_irq(desc);
2185 if (irq <= 0) {
2186 ret = -ENODEV;
2187 goto out_free_le;
2188 }
2189
2190 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
2191 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
2192 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
2193 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
2194 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
2195 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
2196 irqflags |= IRQF_ONESHOT;
2197
2198 INIT_KFIFO(le->events);
2199 init_waitqueue_head(&le->wait);
2200
2201 le->device_unregistered_nb.notifier_call = lineevent_unregistered_notify;
2202 ret = blocking_notifier_chain_register(&gdev->device_notifier,
2203 &le->device_unregistered_nb);
2204 if (ret)
2205 goto out_free_le;
2206
2207 /* Request a thread to read the events */
2208 ret = request_threaded_irq(irq,
2209 lineevent_irq_handler,
2210 lineevent_irq_thread,
2211 irqflags,
2212 le->label,
2213 le);
2214 if (ret)
2215 goto out_free_le;
2216
2217 le->irq = irq;
2218
2219 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
2220 if (fd < 0) {
2221 ret = fd;
2222 goto out_free_le;
2223 }
2224
2225 file = anon_inode_getfile("gpio-event",
2226 &lineevent_fileops,
2227 le,
2228 O_RDONLY | O_CLOEXEC);
2229 if (IS_ERR(file)) {
2230 ret = PTR_ERR(file);
2231 goto out_put_unused_fd;
2232 }
2233
2234 eventreq.fd = fd;
2235 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) {
2236 /*
2237 * fput() will trigger the release() callback, so do not go onto
2238 * the regular error cleanup path here.
2239 */
2240 fput(file);
2241 put_unused_fd(fd);
2242 return -EFAULT;
2243 }
2244
2245 fd_install(fd, file);
2246
2247 return 0;
2248
2249out_put_unused_fd:
2250 put_unused_fd(fd);
2251out_free_le:
2252 lineevent_free(le);
2253 return ret;
2254}
2255
2256static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2,
2257 struct gpioline_info *info_v1)
2258{
2259 u64 flagsv2 = info_v2->flags;
2260
2261 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name));
2262 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer));
2263 info_v1->line_offset = info_v2->offset;
2264 info_v1->flags = 0;
2265
2266 if (flagsv2 & GPIO_V2_LINE_FLAG_USED)
2267 info_v1->flags |= GPIOLINE_FLAG_KERNEL;
2268
2269 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT)
2270 info_v1->flags |= GPIOLINE_FLAG_IS_OUT;
2271
2272 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
2273 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
2274
2275 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN)
2276 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN;
2277 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE)
2278 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE;
2279
2280 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)
2281 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
2282 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN)
2283 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
2284 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED)
2285 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
2286}
2287
2288static void gpio_v2_line_info_changed_to_v1(
2289 struct gpio_v2_line_info_changed *lic_v2,
2290 struct gpioline_info_changed *lic_v1)
2291{
2292 memset(lic_v1, 0, sizeof(*lic_v1));
2293 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info);
2294 lic_v1->timestamp = lic_v2->timestamp_ns;
2295 lic_v1->event_type = lic_v2->event_type;
2296}
2297
2298#endif /* CONFIG_GPIO_CDEV_V1 */
2299
2300static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
2301 struct gpio_v2_line_info *info)
2302{
2303 struct gpio_chip *gc = desc->gdev->chip;
2304 unsigned long dflags;
2305
2306 memset(info, 0, sizeof(*info));
2307 info->offset = gpio_chip_hwgpio(desc);
2308
2309 scoped_guard(spinlock_irqsave, &gpio_lock) {
2310 if (desc->name)
2311 strscpy(info->name, desc->name, sizeof(info->name));
2312
2313 if (desc->label)
2314 strscpy(info->consumer, desc->label,
2315 sizeof(info->consumer));
2316
2317 dflags = READ_ONCE(desc->flags);
2318 }
2319
2320 /*
2321 * Userspace only need know that the kernel is using this GPIO so it
2322 * can't use it.
2323 * The calculation of the used flag is slightly racy, as it may read
2324 * desc, gc and pinctrl state without a lock covering all three at
2325 * once. Worst case if the line is in transition and the calculation
2326 * is inconsistent then it looks to the user like they performed the
2327 * read on the other side of the transition - but that can always
2328 * happen.
2329 * The definitive test that a line is available to userspace is to
2330 * request it.
2331 */
2332 if (test_bit(FLAG_REQUESTED, &dflags) ||
2333 test_bit(FLAG_IS_HOGGED, &dflags) ||
2334 test_bit(FLAG_USED_AS_IRQ, &dflags) ||
2335 test_bit(FLAG_EXPORT, &dflags) ||
2336 test_bit(FLAG_SYSFS, &dflags) ||
2337 !gpiochip_line_is_valid(gc, info->offset) ||
2338 !pinctrl_gpio_can_use_line(gc, info->offset))
2339 info->flags |= GPIO_V2_LINE_FLAG_USED;
2340
2341 if (test_bit(FLAG_IS_OUT, &dflags))
2342 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
2343 else
2344 info->flags |= GPIO_V2_LINE_FLAG_INPUT;
2345
2346 if (test_bit(FLAG_ACTIVE_LOW, &dflags))
2347 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
2348
2349 if (test_bit(FLAG_OPEN_DRAIN, &dflags))
2350 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
2351 if (test_bit(FLAG_OPEN_SOURCE, &dflags))
2352 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
2353
2354 if (test_bit(FLAG_BIAS_DISABLE, &dflags))
2355 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
2356 if (test_bit(FLAG_PULL_DOWN, &dflags))
2357 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
2358 if (test_bit(FLAG_PULL_UP, &dflags))
2359 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
2360
2361 if (test_bit(FLAG_EDGE_RISING, &dflags))
2362 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
2363 if (test_bit(FLAG_EDGE_FALLING, &dflags))
2364 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
2365
2366 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &dflags))
2367 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME;
2368 else if (test_bit(FLAG_EVENT_CLOCK_HTE, &dflags))
2369 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE;
2370}
2371
2372struct gpio_chardev_data {
2373 struct gpio_device *gdev;
2374 wait_queue_head_t wait;
2375 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32);
2376 struct notifier_block lineinfo_changed_nb;
2377 struct notifier_block device_unregistered_nb;
2378 unsigned long *watched_lines;
2379#ifdef CONFIG_GPIO_CDEV_V1
2380 atomic_t watch_abi_version;
2381#endif
2382};
2383
2384static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip)
2385{
2386 struct gpio_device *gdev = cdev->gdev;
2387 struct gpiochip_info chipinfo;
2388
2389 memset(&chipinfo, 0, sizeof(chipinfo));
2390
2391 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name));
2392 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label));
2393 chipinfo.lines = gdev->ngpio;
2394 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
2395 return -EFAULT;
2396 return 0;
2397}
2398
2399#ifdef CONFIG_GPIO_CDEV_V1
2400/*
2401 * returns 0 if the versions match, else the previously selected ABI version
2402 */
2403static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata,
2404 unsigned int version)
2405{
2406 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version);
2407
2408 if (abiv == version)
2409 return 0;
2410
2411 return abiv;
2412}
2413
2414static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
2415 bool watch)
2416{
2417 struct gpio_desc *desc;
2418 struct gpioline_info lineinfo;
2419 struct gpio_v2_line_info lineinfo_v2;
2420
2421 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2422 return -EFAULT;
2423
2424 /* this doubles as a range check on line_offset */
2425 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset);
2426 if (IS_ERR(desc))
2427 return PTR_ERR(desc);
2428
2429 if (watch) {
2430 if (lineinfo_ensure_abi_version(cdev, 1))
2431 return -EPERM;
2432
2433 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
2434 return -EBUSY;
2435 }
2436
2437 gpio_desc_to_lineinfo(desc, &lineinfo_v2);
2438 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
2439
2440 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2441 if (watch)
2442 clear_bit(lineinfo.line_offset, cdev->watched_lines);
2443 return -EFAULT;
2444 }
2445
2446 return 0;
2447}
2448#endif
2449
2450static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
2451 bool watch)
2452{
2453 struct gpio_desc *desc;
2454 struct gpio_v2_line_info lineinfo;
2455
2456 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2457 return -EFAULT;
2458
2459 if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding)))
2460 return -EINVAL;
2461
2462 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset);
2463 if (IS_ERR(desc))
2464 return PTR_ERR(desc);
2465
2466 if (watch) {
2467#ifdef CONFIG_GPIO_CDEV_V1
2468 if (lineinfo_ensure_abi_version(cdev, 2))
2469 return -EPERM;
2470#endif
2471 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
2472 return -EBUSY;
2473 }
2474 gpio_desc_to_lineinfo(desc, &lineinfo);
2475 supinfo_to_lineinfo(desc, &lineinfo);
2476
2477 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2478 if (watch)
2479 clear_bit(lineinfo.offset, cdev->watched_lines);
2480 return -EFAULT;
2481 }
2482
2483 return 0;
2484}
2485
2486static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip)
2487{
2488 __u32 offset;
2489
2490 if (copy_from_user(&offset, ip, sizeof(offset)))
2491 return -EFAULT;
2492
2493 if (offset >= cdev->gdev->ngpio)
2494 return -EINVAL;
2495
2496 if (!test_and_clear_bit(offset, cdev->watched_lines))
2497 return -EBUSY;
2498
2499 return 0;
2500}
2501
2502/*
2503 * gpio_ioctl() - ioctl handler for the GPIO chardev
2504 */
2505static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2506{
2507 struct gpio_chardev_data *cdev = file->private_data;
2508 struct gpio_device *gdev = cdev->gdev;
2509 void __user *ip = (void __user *)arg;
2510
2511 guard(rwsem_read)(&gdev->sem);
2512
2513 /* We fail any subsequent ioctl():s when the chip is gone */
2514 if (!gdev->chip)
2515 return -ENODEV;
2516
2517 /* Fill in the struct and pass to userspace */
2518 switch (cmd) {
2519 case GPIO_GET_CHIPINFO_IOCTL:
2520 return chipinfo_get(cdev, ip);
2521#ifdef CONFIG_GPIO_CDEV_V1
2522 case GPIO_GET_LINEHANDLE_IOCTL:
2523 return linehandle_create(gdev, ip);
2524 case GPIO_GET_LINEEVENT_IOCTL:
2525 return lineevent_create(gdev, ip);
2526 case GPIO_GET_LINEINFO_IOCTL:
2527 return lineinfo_get_v1(cdev, ip, false);
2528 case GPIO_GET_LINEINFO_WATCH_IOCTL:
2529 return lineinfo_get_v1(cdev, ip, true);
2530#endif /* CONFIG_GPIO_CDEV_V1 */
2531 case GPIO_V2_GET_LINEINFO_IOCTL:
2532 return lineinfo_get(cdev, ip, false);
2533 case GPIO_V2_GET_LINEINFO_WATCH_IOCTL:
2534 return lineinfo_get(cdev, ip, true);
2535 case GPIO_V2_GET_LINE_IOCTL:
2536 return linereq_create(gdev, ip);
2537 case GPIO_GET_LINEINFO_UNWATCH_IOCTL:
2538 return lineinfo_unwatch(cdev, ip);
2539 default:
2540 return -EINVAL;
2541 }
2542}
2543
2544#ifdef CONFIG_COMPAT
2545static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
2546 unsigned long arg)
2547{
2548 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2549}
2550#endif
2551
2552static int lineinfo_changed_notify(struct notifier_block *nb,
2553 unsigned long action, void *data)
2554{
2555 struct gpio_chardev_data *cdev =
2556 container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
2557 struct gpio_v2_line_info_changed chg;
2558 struct gpio_desc *desc = data;
2559 int ret;
2560
2561 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines))
2562 return NOTIFY_DONE;
2563
2564 memset(&chg, 0, sizeof(chg));
2565 chg.event_type = action;
2566 chg.timestamp_ns = ktime_get_ns();
2567 gpio_desc_to_lineinfo(desc, &chg.info);
2568 supinfo_to_lineinfo(desc, &chg.info);
2569
2570 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
2571 if (ret)
2572 wake_up_poll(&cdev->wait, EPOLLIN);
2573 else
2574 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");
2575
2576 return NOTIFY_OK;
2577}
2578
2579static int gpio_device_unregistered_notify(struct notifier_block *nb,
2580 unsigned long action, void *data)
2581{
2582 struct gpio_chardev_data *cdev = container_of(nb,
2583 struct gpio_chardev_data,
2584 device_unregistered_nb);
2585
2586 wake_up_poll(&cdev->wait, EPOLLIN | EPOLLERR);
2587
2588 return NOTIFY_OK;
2589}
2590
2591static __poll_t lineinfo_watch_poll(struct file *file,
2592 struct poll_table_struct *pollt)
2593{
2594 struct gpio_chardev_data *cdev = file->private_data;
2595 __poll_t events = 0;
2596
2597 guard(rwsem_read)(&cdev->gdev->sem);
2598
2599 if (!cdev->gdev->chip)
2600 return EPOLLHUP | EPOLLERR;
2601
2602 poll_wait(file, &cdev->wait, pollt);
2603
2604 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events,
2605 &cdev->wait.lock))
2606 events = EPOLLIN | EPOLLRDNORM;
2607
2608 return events;
2609}
2610
2611static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
2612 size_t count, loff_t *off)
2613{
2614 struct gpio_chardev_data *cdev = file->private_data;
2615 struct gpio_v2_line_info_changed event;
2616 ssize_t bytes_read = 0;
2617 int ret;
2618 size_t event_size;
2619
2620 guard(rwsem_read)(&cdev->gdev->sem);
2621
2622 if (!cdev->gdev->chip)
2623 return -ENODEV;
2624
2625#ifndef CONFIG_GPIO_CDEV_V1
2626 event_size = sizeof(struct gpio_v2_line_info_changed);
2627 if (count < event_size)
2628 return -EINVAL;
2629#endif
2630
2631 do {
2632 scoped_guard(spinlock, &cdev->wait.lock) {
2633 if (kfifo_is_empty(&cdev->events)) {
2634 if (bytes_read)
2635 return bytes_read;
2636
2637 if (file->f_flags & O_NONBLOCK)
2638 return -EAGAIN;
2639
2640 ret = wait_event_interruptible_locked(cdev->wait,
2641 !kfifo_is_empty(&cdev->events));
2642 if (ret)
2643 return ret;
2644 }
2645#ifdef CONFIG_GPIO_CDEV_V1
2646 /* must be after kfifo check so watch_abi_version is set */
2647 if (atomic_read(&cdev->watch_abi_version) == 2)
2648 event_size = sizeof(struct gpio_v2_line_info_changed);
2649 else
2650 event_size = sizeof(struct gpioline_info_changed);
2651 if (count < event_size)
2652 return -EINVAL;
2653#endif
2654 ret = kfifo_out(&cdev->events, &event, 1);
2655 }
2656 if (ret != 1) {
2657 ret = -EIO;
2658 break;
2659 /* We should never get here. See lineevent_read(). */
2660 }
2661
2662#ifdef CONFIG_GPIO_CDEV_V1
2663 if (event_size == sizeof(struct gpio_v2_line_info_changed)) {
2664 if (copy_to_user(buf + bytes_read, &event, event_size))
2665 return -EFAULT;
2666 } else {
2667 struct gpioline_info_changed event_v1;
2668
2669 gpio_v2_line_info_changed_to_v1(&event, &event_v1);
2670 if (copy_to_user(buf + bytes_read, &event_v1,
2671 event_size))
2672 return -EFAULT;
2673 }
2674#else
2675 if (copy_to_user(buf + bytes_read, &event, event_size))
2676 return -EFAULT;
2677#endif
2678 bytes_read += event_size;
2679 } while (count >= bytes_read + sizeof(event));
2680
2681 return bytes_read;
2682}
2683
2684/**
2685 * gpio_chrdev_open() - open the chardev for ioctl operations
2686 * @inode: inode for this chardev
2687 * @file: file struct for storing private data
2688 * Returns 0 on success
2689 */
2690static int gpio_chrdev_open(struct inode *inode, struct file *file)
2691{
2692 struct gpio_device *gdev = container_of(inode->i_cdev,
2693 struct gpio_device, chrdev);
2694 struct gpio_chardev_data *cdev;
2695 int ret = -ENOMEM;
2696
2697 guard(rwsem_read)(&gdev->sem);
2698
2699 /* Fail on open if the backing gpiochip is gone */
2700 if (!gdev->chip)
2701 return -ENODEV;
2702
2703 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
2704 if (!cdev)
2705 return -ENODEV;
2706
2707 cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL);
2708 if (!cdev->watched_lines)
2709 goto out_free_cdev;
2710
2711 init_waitqueue_head(&cdev->wait);
2712 INIT_KFIFO(cdev->events);
2713 cdev->gdev = gpio_device_get(gdev);
2714
2715 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
2716 ret = blocking_notifier_chain_register(&gdev->line_state_notifier,
2717 &cdev->lineinfo_changed_nb);
2718 if (ret)
2719 goto out_free_bitmap;
2720
2721 cdev->device_unregistered_nb.notifier_call =
2722 gpio_device_unregistered_notify;
2723 ret = blocking_notifier_chain_register(&gdev->device_notifier,
2724 &cdev->device_unregistered_nb);
2725 if (ret)
2726 goto out_unregister_line_notifier;
2727
2728 file->private_data = cdev;
2729
2730 ret = nonseekable_open(inode, file);
2731 if (ret)
2732 goto out_unregister_device_notifier;
2733
2734 return ret;
2735
2736out_unregister_device_notifier:
2737 blocking_notifier_chain_unregister(&gdev->device_notifier,
2738 &cdev->device_unregistered_nb);
2739out_unregister_line_notifier:
2740 blocking_notifier_chain_unregister(&gdev->line_state_notifier,
2741 &cdev->lineinfo_changed_nb);
2742out_free_bitmap:
2743 gpio_device_put(gdev);
2744 bitmap_free(cdev->watched_lines);
2745out_free_cdev:
2746 kfree(cdev);
2747 return ret;
2748}
2749
2750/**
2751 * gpio_chrdev_release() - close chardev after ioctl operations
2752 * @inode: inode for this chardev
2753 * @file: file struct for storing private data
2754 * Returns 0 on success
2755 */
2756static int gpio_chrdev_release(struct inode *inode, struct file *file)
2757{
2758 struct gpio_chardev_data *cdev = file->private_data;
2759 struct gpio_device *gdev = cdev->gdev;
2760
2761 bitmap_free(cdev->watched_lines);
2762 blocking_notifier_chain_unregister(&gdev->device_notifier,
2763 &cdev->device_unregistered_nb);
2764 blocking_notifier_chain_unregister(&gdev->line_state_notifier,
2765 &cdev->lineinfo_changed_nb);
2766 gpio_device_put(gdev);
2767 kfree(cdev);
2768
2769 return 0;
2770}
2771
2772static const struct file_operations gpio_fileops = {
2773 .release = gpio_chrdev_release,
2774 .open = gpio_chrdev_open,
2775 .poll = lineinfo_watch_poll,
2776 .read = lineinfo_watch_read,
2777 .owner = THIS_MODULE,
2778 .llseek = no_llseek,
2779 .unlocked_ioctl = gpio_ioctl,
2780#ifdef CONFIG_COMPAT
2781 .compat_ioctl = gpio_ioctl_compat,
2782#endif
2783};
2784
2785int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
2786{
2787 int ret;
2788
2789 cdev_init(&gdev->chrdev, &gpio_fileops);
2790 gdev->chrdev.owner = THIS_MODULE;
2791 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
2792
2793 ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
2794 if (ret)
2795 return ret;
2796
2797 chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
2798 MAJOR(devt), gdev->id);
2799
2800 return 0;
2801}
2802
2803void gpiolib_cdev_unregister(struct gpio_device *gdev)
2804{
2805 cdev_device_del(&gdev->chrdev, &gdev->dev);
2806 blocking_notifier_call_chain(&gdev->device_notifier, 0, NULL);
2807}
Linux 6.x block layer and io_uring tree(s)