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 */
36 static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2));
37 static_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 */
42 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8));
43 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8));
44 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8));
45 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8));
46 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8));
47 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8));
48 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8));
49 static_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 */
69 struct 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
linehandle_validate_flags(u32 flags)86 static 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
linehandle_flags_to_desc_flags(u32 lflags,unsigned long * flagsp)134 static 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
linehandle_set_config(struct linehandle_state * lh,void __user * ip)150 static 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
linehandle_ioctl(struct file * file,unsigned int cmd,unsigned long arg)193 static 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
linehandle_ioctl_compat(struct file * file,unsigned int cmd,unsigned long arg)250 static 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
linehandle_free(struct linehandle_state * lh)257 static 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
linehandle_release(struct inode * inode,struct file * file)269 static int linehandle_release(struct inode *inode, struct file *file)
270 {
271 linehandle_free(file->private_data);
272 return 0;
273 }
274
275 static 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
linehandle_create(struct gpio_device * gdev,void __user * ip)285 static 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
399 out_put_unused_fd:
400 put_unused_fd(fd);
401 out_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 */
424 struct line {
425 struct gpio_desc *desc;
426 /*
427 * -- edge detector specific fields --
428 */
429 struct linereq *req;
430 unsigned int irq;
431 u64 eflags;
432 /*
433 * timestamp_ns and req_seqno are accessed only by
434 * edge_irq_handler() and edge_irq_thread(), which are themselves
435 * mutually exclusive, so no additional protection is necessary.
436 */
437 u64 timestamp_ns;
438 u32 req_seqno;
439 /*
440 * line_seqno is accessed by either edge_irq_thread() or
441 * debounce_work_func(), which are themselves mutually exclusive,
442 * so no additional protection is necessary.
443 */
444 u32 line_seqno;
445 /*
446 * -- debouncer specific fields --
447 */
448 struct delayed_work work;
449 /*
450 * sw_debounce is accessed by linereq_set_config(), which is the
451 * only setter, and linereq_get_values(), which can live with a
452 * slightly stale value.
453 */
454 unsigned int sw_debounced;
455 /*
456 * level is accessed by debounce_work_func(), which is the only
457 * setter, and linereq_get_values() which can live with a slightly
458 * stale value.
459 */
460 unsigned int level;
461 };
462
463 /**
464 * struct linereq - contains the state of a userspace line request
465 * @gdev: the GPIO device the line request pertains to
466 * @label: consumer label used to tag GPIO descriptors
467 * @num_lines: the number of lines in the lines array
468 * @wait: wait queue that handles blocking reads of events
469 * @event_buffer_size: the number of elements allocated in @events
470 * @events: KFIFO for the GPIO events
471 * @seqno: the sequence number for edge events generated on all lines in
472 * this line request. Note that this is not used when @num_lines is 1, as
473 * the line_seqno is then the same and is cheaper to calculate.
474 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency
475 * of configuration, particularly multi-step accesses to desc flags.
476 * @lines: the lines held by this line request, with @num_lines elements.
477 */
478 struct linereq {
479 struct gpio_device *gdev;
480 const char *label;
481 u32 num_lines;
482 wait_queue_head_t wait;
483 u32 event_buffer_size;
484 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
485 atomic_t seqno;
486 struct mutex config_mutex;
487 struct line lines[];
488 };
489
490 #define GPIO_V2_LINE_BIAS_FLAGS \
491 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \
492 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \
493 GPIO_V2_LINE_FLAG_BIAS_DISABLED)
494
495 #define GPIO_V2_LINE_DIRECTION_FLAGS \
496 (GPIO_V2_LINE_FLAG_INPUT | \
497 GPIO_V2_LINE_FLAG_OUTPUT)
498
499 #define GPIO_V2_LINE_DRIVE_FLAGS \
500 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \
501 GPIO_V2_LINE_FLAG_OPEN_SOURCE)
502
503 #define GPIO_V2_LINE_EDGE_FLAGS \
504 (GPIO_V2_LINE_FLAG_EDGE_RISING | \
505 GPIO_V2_LINE_FLAG_EDGE_FALLING)
506
507 #define GPIO_V2_LINE_VALID_FLAGS \
508 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
509 GPIO_V2_LINE_DIRECTION_FLAGS | \
510 GPIO_V2_LINE_DRIVE_FLAGS | \
511 GPIO_V2_LINE_EDGE_FLAGS | \
512 GPIO_V2_LINE_BIAS_FLAGS)
513
linereq_put_event(struct linereq * lr,struct gpio_v2_line_event * le)514 static void linereq_put_event(struct linereq *lr,
515 struct gpio_v2_line_event *le)
516 {
517 bool overflow = false;
518
519 spin_lock(&lr->wait.lock);
520 if (kfifo_is_full(&lr->events)) {
521 overflow = true;
522 kfifo_skip(&lr->events);
523 }
524 kfifo_in(&lr->events, le, 1);
525 spin_unlock(&lr->wait.lock);
526 if (!overflow)
527 wake_up_poll(&lr->wait, EPOLLIN);
528 else
529 pr_debug_ratelimited("event FIFO is full - event dropped\n");
530 }
531
edge_irq_thread(int irq,void * p)532 static irqreturn_t edge_irq_thread(int irq, void *p)
533 {
534 struct line *line = p;
535 struct linereq *lr = line->req;
536 struct gpio_v2_line_event le;
537
538 /* Do not leak kernel stack to userspace */
539 memset(&le, 0, sizeof(le));
540
541 if (line->timestamp_ns) {
542 le.timestamp_ns = line->timestamp_ns;
543 } else {
544 /*
545 * We may be running from a nested threaded interrupt in
546 * which case we didn't get the timestamp from
547 * edge_irq_handler().
548 */
549 le.timestamp_ns = ktime_get_ns();
550 if (lr->num_lines != 1)
551 line->req_seqno = atomic_inc_return(&lr->seqno);
552 }
553 line->timestamp_ns = 0;
554
555 if (line->eflags == (GPIO_V2_LINE_FLAG_EDGE_RISING |
556 GPIO_V2_LINE_FLAG_EDGE_FALLING)) {
557 int level = gpiod_get_value_cansleep(line->desc);
558
559 if (level)
560 /* Emit low-to-high event */
561 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
562 else
563 /* Emit high-to-low event */
564 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
565 } else if (line->eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) {
566 /* Emit low-to-high event */
567 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
568 } else if (line->eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) {
569 /* Emit high-to-low event */
570 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
571 } else {
572 return IRQ_NONE;
573 }
574 line->line_seqno++;
575 le.line_seqno = line->line_seqno;
576 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
577 le.offset = gpio_chip_hwgpio(line->desc);
578
579 linereq_put_event(lr, &le);
580
581 return IRQ_HANDLED;
582 }
583
edge_irq_handler(int irq,void * p)584 static irqreturn_t edge_irq_handler(int irq, void *p)
585 {
586 struct line *line = p;
587 struct linereq *lr = line->req;
588
589 /*
590 * Just store the timestamp in hardirq context so we get it as
591 * close in time as possible to the actual event.
592 */
593 line->timestamp_ns = ktime_get_ns();
594
595 if (lr->num_lines != 1)
596 line->req_seqno = atomic_inc_return(&lr->seqno);
597
598 return IRQ_WAKE_THREAD;
599 }
600
601 /*
602 * returns the current debounced logical value.
603 */
debounced_value(struct line * line)604 static bool debounced_value(struct line *line)
605 {
606 bool value;
607
608 /*
609 * minor race - debouncer may be stopped here, so edge_detector_stop()
610 * must leave the value unchanged so the following will read the level
611 * from when the debouncer was last running.
612 */
613 value = READ_ONCE(line->level);
614
615 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
616 value = !value;
617
618 return value;
619 }
620
debounce_irq_handler(int irq,void * p)621 static irqreturn_t debounce_irq_handler(int irq, void *p)
622 {
623 struct line *line = p;
624
625 mod_delayed_work(system_wq, &line->work,
626 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
627
628 return IRQ_HANDLED;
629 }
630
debounce_work_func(struct work_struct * work)631 static void debounce_work_func(struct work_struct *work)
632 {
633 struct gpio_v2_line_event le;
634 struct line *line = container_of(work, struct line, work.work);
635 struct linereq *lr;
636 int level;
637
638 level = gpiod_get_raw_value_cansleep(line->desc);
639 if (level < 0) {
640 pr_debug_ratelimited("debouncer failed to read line value\n");
641 return;
642 }
643
644 if (READ_ONCE(line->level) == level)
645 return;
646
647 WRITE_ONCE(line->level, level);
648
649 /* -- edge detection -- */
650 if (!line->eflags)
651 return;
652
653 /* switch from physical level to logical - if they differ */
654 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
655 level = !level;
656
657 /* ignore edges that are not being monitored */
658 if (((line->eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) ||
659 ((line->eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level))
660 return;
661
662 /* Do not leak kernel stack to userspace */
663 memset(&le, 0, sizeof(le));
664
665 lr = line->req;
666 le.timestamp_ns = ktime_get_ns();
667 le.offset = gpio_chip_hwgpio(line->desc);
668 line->line_seqno++;
669 le.line_seqno = line->line_seqno;
670 le.seqno = (lr->num_lines == 1) ?
671 le.line_seqno : atomic_inc_return(&lr->seqno);
672
673 if (level)
674 /* Emit low-to-high event */
675 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
676 else
677 /* Emit high-to-low event */
678 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
679
680 linereq_put_event(lr, &le);
681 }
682
debounce_setup(struct line * line,unsigned int debounce_period_us)683 static int debounce_setup(struct line *line,
684 unsigned int debounce_period_us)
685 {
686 unsigned long irqflags;
687 int ret, level, irq;
688
689 /* try hardware */
690 ret = gpiod_set_debounce(line->desc, debounce_period_us);
691 if (!ret) {
692 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
693 return ret;
694 }
695 if (ret != -ENOTSUPP)
696 return ret;
697
698 if (debounce_period_us) {
699 /* setup software debounce */
700 level = gpiod_get_raw_value_cansleep(line->desc);
701 if (level < 0)
702 return level;
703
704 irq = gpiod_to_irq(line->desc);
705 if (irq < 0)
706 return -ENXIO;
707
708 WRITE_ONCE(line->level, level);
709 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
710 ret = request_irq(irq, debounce_irq_handler, irqflags,
711 line->req->label, line);
712 if (ret)
713 return ret;
714
715 WRITE_ONCE(line->sw_debounced, 1);
716 line->irq = irq;
717 }
718 return 0;
719 }
720
gpio_v2_line_config_debounced(struct gpio_v2_line_config * lc,unsigned int line_idx)721 static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc,
722 unsigned int line_idx)
723 {
724 unsigned int i;
725 u64 mask = BIT_ULL(line_idx);
726
727 for (i = 0; i < lc->num_attrs; i++) {
728 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
729 (lc->attrs[i].mask & mask))
730 return true;
731 }
732 return false;
733 }
734
gpio_v2_line_config_debounce_period(struct gpio_v2_line_config * lc,unsigned int line_idx)735 static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
736 unsigned int line_idx)
737 {
738 unsigned int i;
739 u64 mask = BIT_ULL(line_idx);
740
741 for (i = 0; i < lc->num_attrs; i++) {
742 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
743 (lc->attrs[i].mask & mask))
744 return lc->attrs[i].attr.debounce_period_us;
745 }
746 return 0;
747 }
748
edge_detector_stop(struct line * line)749 static void edge_detector_stop(struct line *line)
750 {
751 if (line->irq) {
752 free_irq(line->irq, line);
753 line->irq = 0;
754 }
755
756 cancel_delayed_work_sync(&line->work);
757 WRITE_ONCE(line->sw_debounced, 0);
758 line->eflags = 0;
759 if (line->desc)
760 WRITE_ONCE(line->desc->debounce_period_us, 0);
761 /* do not change line->level - see comment in debounced_value() */
762 }
763
edge_detector_setup(struct line * line,struct gpio_v2_line_config * lc,unsigned int line_idx,u64 eflags)764 static int edge_detector_setup(struct line *line,
765 struct gpio_v2_line_config *lc,
766 unsigned int line_idx,
767 u64 eflags)
768 {
769 u32 debounce_period_us;
770 unsigned long irqflags = 0;
771 int irq, ret;
772
773 if (eflags && !kfifo_initialized(&line->req->events)) {
774 ret = kfifo_alloc(&line->req->events,
775 line->req->event_buffer_size, GFP_KERNEL);
776 if (ret)
777 return ret;
778 }
779 line->eflags = eflags;
780 if (gpio_v2_line_config_debounced(lc, line_idx)) {
781 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
782 ret = debounce_setup(line, debounce_period_us);
783 if (ret)
784 return ret;
785 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
786 }
787
788 /* detection disabled or sw debouncer will provide edge detection */
789 if (!eflags || READ_ONCE(line->sw_debounced))
790 return 0;
791
792 irq = gpiod_to_irq(line->desc);
793 if (irq < 0)
794 return -ENXIO;
795
796 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
797 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
798 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
799 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
800 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
801 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
802 irqflags |= IRQF_ONESHOT;
803
804 /* Request a thread to read the events */
805 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
806 irqflags, line->req->label, line);
807 if (ret)
808 return ret;
809
810 line->irq = irq;
811 return 0;
812 }
813
edge_detector_update(struct line * line,struct gpio_v2_line_config * lc,unsigned int line_idx,u64 eflags,bool polarity_change)814 static int edge_detector_update(struct line *line,
815 struct gpio_v2_line_config *lc,
816 unsigned int line_idx,
817 u64 eflags, bool polarity_change)
818 {
819 unsigned int debounce_period_us =
820 gpio_v2_line_config_debounce_period(lc, line_idx);
821
822 if ((line->eflags == eflags) && !polarity_change &&
823 (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us))
824 return 0;
825
826 /* sw debounced and still will be...*/
827 if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
828 line->eflags = eflags;
829 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
830 return 0;
831 }
832
833 /* reconfiguring edge detection or sw debounce being disabled */
834 if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
835 (!debounce_period_us && READ_ONCE(line->sw_debounced)))
836 edge_detector_stop(line);
837
838 return edge_detector_setup(line, lc, line_idx, eflags);
839 }
840
gpio_v2_line_config_flags(struct gpio_v2_line_config * lc,unsigned int line_idx)841 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
842 unsigned int line_idx)
843 {
844 unsigned int i;
845 u64 mask = BIT_ULL(line_idx);
846
847 for (i = 0; i < lc->num_attrs; i++) {
848 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) &&
849 (lc->attrs[i].mask & mask))
850 return lc->attrs[i].attr.flags;
851 }
852 return lc->flags;
853 }
854
gpio_v2_line_config_output_value(struct gpio_v2_line_config * lc,unsigned int line_idx)855 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc,
856 unsigned int line_idx)
857 {
858 unsigned int i;
859 u64 mask = BIT_ULL(line_idx);
860
861 for (i = 0; i < lc->num_attrs; i++) {
862 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) &&
863 (lc->attrs[i].mask & mask))
864 return !!(lc->attrs[i].attr.values & mask);
865 }
866 return 0;
867 }
868
gpio_v2_line_flags_validate(u64 flags)869 static int gpio_v2_line_flags_validate(u64 flags)
870 {
871 /* Return an error if an unknown flag is set */
872 if (flags & ~GPIO_V2_LINE_VALID_FLAGS)
873 return -EINVAL;
874
875 /*
876 * Do not allow both INPUT and OUTPUT flags to be set as they are
877 * contradictory.
878 */
879 if ((flags & GPIO_V2_LINE_FLAG_INPUT) &&
880 (flags & GPIO_V2_LINE_FLAG_OUTPUT))
881 return -EINVAL;
882
883 /* Edge detection requires explicit input. */
884 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) &&
885 !(flags & GPIO_V2_LINE_FLAG_INPUT))
886 return -EINVAL;
887
888 /*
889 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single
890 * request. If the hardware actually supports enabling both at the
891 * same time the electrical result would be disastrous.
892 */
893 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) &&
894 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE))
895 return -EINVAL;
896
897 /* Drive requires explicit output direction. */
898 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) &&
899 !(flags & GPIO_V2_LINE_FLAG_OUTPUT))
900 return -EINVAL;
901
902 /* Bias requires explicit direction. */
903 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) &&
904 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
905 return -EINVAL;
906
907 /* Only one bias flag can be set. */
908 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) &&
909 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN |
910 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) ||
911 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) &&
912 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)))
913 return -EINVAL;
914
915 return 0;
916 }
917
gpio_v2_line_config_validate(struct gpio_v2_line_config * lc,unsigned int num_lines)918 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
919 unsigned int num_lines)
920 {
921 unsigned int i;
922 u64 flags;
923 int ret;
924
925 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX)
926 return -EINVAL;
927
928 if (memchr_inv(lc->padding, 0, sizeof(lc->padding)))
929 return -EINVAL;
930
931 for (i = 0; i < num_lines; i++) {
932 flags = gpio_v2_line_config_flags(lc, i);
933 ret = gpio_v2_line_flags_validate(flags);
934 if (ret)
935 return ret;
936
937 /* debounce requires explicit input */
938 if (gpio_v2_line_config_debounced(lc, i) &&
939 !(flags & GPIO_V2_LINE_FLAG_INPUT))
940 return -EINVAL;
941 }
942 return 0;
943 }
944
gpio_v2_line_config_flags_to_desc_flags(u64 flags,unsigned long * flagsp)945 static void gpio_v2_line_config_flags_to_desc_flags(u64 flags,
946 unsigned long *flagsp)
947 {
948 assign_bit(FLAG_ACTIVE_LOW, flagsp,
949 flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW);
950
951 if (flags & GPIO_V2_LINE_FLAG_OUTPUT)
952 set_bit(FLAG_IS_OUT, flagsp);
953 else if (flags & GPIO_V2_LINE_FLAG_INPUT)
954 clear_bit(FLAG_IS_OUT, flagsp);
955
956 assign_bit(FLAG_EDGE_RISING, flagsp,
957 flags & GPIO_V2_LINE_FLAG_EDGE_RISING);
958 assign_bit(FLAG_EDGE_FALLING, flagsp,
959 flags & GPIO_V2_LINE_FLAG_EDGE_FALLING);
960
961 assign_bit(FLAG_OPEN_DRAIN, flagsp,
962 flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN);
963 assign_bit(FLAG_OPEN_SOURCE, flagsp,
964 flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE);
965
966 assign_bit(FLAG_PULL_UP, flagsp,
967 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP);
968 assign_bit(FLAG_PULL_DOWN, flagsp,
969 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN);
970 assign_bit(FLAG_BIAS_DISABLE, flagsp,
971 flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED);
972 }
973
linereq_get_values(struct linereq * lr,void __user * ip)974 static long linereq_get_values(struct linereq *lr, void __user *ip)
975 {
976 struct gpio_v2_line_values lv;
977 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
978 struct gpio_desc **descs;
979 unsigned int i, didx, num_get;
980 bool val;
981 int ret;
982
983 /* NOTE: It's ok to read values of output lines. */
984 if (copy_from_user(&lv, ip, sizeof(lv)))
985 return -EFAULT;
986
987 for (num_get = 0, i = 0; i < lr->num_lines; i++) {
988 if (lv.mask & BIT_ULL(i)) {
989 num_get++;
990 descs = &lr->lines[i].desc;
991 }
992 }
993
994 if (num_get == 0)
995 return -EINVAL;
996
997 if (num_get != 1) {
998 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL);
999 if (!descs)
1000 return -ENOMEM;
1001 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1002 if (lv.mask & BIT_ULL(i)) {
1003 descs[didx] = lr->lines[i].desc;
1004 didx++;
1005 }
1006 }
1007 }
1008 ret = gpiod_get_array_value_complex(false, true, num_get,
1009 descs, NULL, vals);
1010
1011 if (num_get != 1)
1012 kfree(descs);
1013 if (ret)
1014 return ret;
1015
1016 lv.bits = 0;
1017 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1018 if (lv.mask & BIT_ULL(i)) {
1019 if (lr->lines[i].sw_debounced)
1020 val = debounced_value(&lr->lines[i]);
1021 else
1022 val = test_bit(didx, vals);
1023 if (val)
1024 lv.bits |= BIT_ULL(i);
1025 didx++;
1026 }
1027 }
1028
1029 if (copy_to_user(ip, &lv, sizeof(lv)))
1030 return -EFAULT;
1031
1032 return 0;
1033 }
1034
linereq_set_values_unlocked(struct linereq * lr,struct gpio_v2_line_values * lv)1035 static long linereq_set_values_unlocked(struct linereq *lr,
1036 struct gpio_v2_line_values *lv)
1037 {
1038 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1039 struct gpio_desc **descs;
1040 unsigned int i, didx, num_set;
1041 int ret;
1042
1043 bitmap_zero(vals, GPIO_V2_LINES_MAX);
1044 for (num_set = 0, i = 0; i < lr->num_lines; i++) {
1045 if (lv->mask & BIT_ULL(i)) {
1046 if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
1047 return -EPERM;
1048 if (lv->bits & BIT_ULL(i))
1049 __set_bit(num_set, vals);
1050 num_set++;
1051 descs = &lr->lines[i].desc;
1052 }
1053 }
1054 if (num_set == 0)
1055 return -EINVAL;
1056
1057 if (num_set != 1) {
1058 /* build compacted desc array and values */
1059 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);
1060 if (!descs)
1061 return -ENOMEM;
1062 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1063 if (lv->mask & BIT_ULL(i)) {
1064 descs[didx] = lr->lines[i].desc;
1065 didx++;
1066 }
1067 }
1068 }
1069 ret = gpiod_set_array_value_complex(false, true, num_set,
1070 descs, NULL, vals);
1071
1072 if (num_set != 1)
1073 kfree(descs);
1074 return ret;
1075 }
1076
linereq_set_values(struct linereq * lr,void __user * ip)1077 static long linereq_set_values(struct linereq *lr, void __user *ip)
1078 {
1079 struct gpio_v2_line_values lv;
1080 int ret;
1081
1082 if (copy_from_user(&lv, ip, sizeof(lv)))
1083 return -EFAULT;
1084
1085 mutex_lock(&lr->config_mutex);
1086
1087 ret = linereq_set_values_unlocked(lr, &lv);
1088
1089 mutex_unlock(&lr->config_mutex);
1090
1091 return ret;
1092 }
1093
linereq_set_config_unlocked(struct linereq * lr,struct gpio_v2_line_config * lc)1094 static long linereq_set_config_unlocked(struct linereq *lr,
1095 struct gpio_v2_line_config *lc)
1096 {
1097 struct gpio_desc *desc;
1098 unsigned int i;
1099 u64 flags;
1100 bool polarity_change;
1101 int ret;
1102
1103 for (i = 0; i < lr->num_lines; i++) {
1104 desc = lr->lines[i].desc;
1105 flags = gpio_v2_line_config_flags(lc, i);
1106 polarity_change =
1107 (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) !=
1108 ((flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) != 0));
1109
1110 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1111 /*
1112 * Lines have to be requested explicitly for input
1113 * or output, else the line will be treated "as is".
1114 */
1115 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1116 int val = gpio_v2_line_config_output_value(lc, i);
1117
1118 edge_detector_stop(&lr->lines[i]);
1119 ret = gpiod_direction_output(desc, val);
1120 if (ret)
1121 return ret;
1122 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1123 ret = gpiod_direction_input(desc);
1124 if (ret)
1125 return ret;
1126
1127 ret = edge_detector_update(&lr->lines[i], lc, i,
1128 flags & GPIO_V2_LINE_EDGE_FLAGS,
1129 polarity_change);
1130 if (ret)
1131 return ret;
1132 }
1133
1134 blocking_notifier_call_chain(&desc->gdev->notifier,
1135 GPIO_V2_LINE_CHANGED_CONFIG,
1136 desc);
1137 }
1138 return 0;
1139 }
1140
linereq_set_config(struct linereq * lr,void __user * ip)1141 static long linereq_set_config(struct linereq *lr, void __user *ip)
1142 {
1143 struct gpio_v2_line_config lc;
1144 int ret;
1145
1146 if (copy_from_user(&lc, ip, sizeof(lc)))
1147 return -EFAULT;
1148
1149 ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
1150 if (ret)
1151 return ret;
1152
1153 mutex_lock(&lr->config_mutex);
1154
1155 ret = linereq_set_config_unlocked(lr, &lc);
1156
1157 mutex_unlock(&lr->config_mutex);
1158
1159 return ret;
1160 }
1161
linereq_ioctl(struct file * file,unsigned int cmd,unsigned long arg)1162 static long linereq_ioctl(struct file *file, unsigned int cmd,
1163 unsigned long arg)
1164 {
1165 struct linereq *lr = file->private_data;
1166 void __user *ip = (void __user *)arg;
1167
1168 if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL)
1169 return linereq_get_values(lr, ip);
1170 else if (cmd == GPIO_V2_LINE_SET_VALUES_IOCTL)
1171 return linereq_set_values(lr, ip);
1172 else if (cmd == GPIO_V2_LINE_SET_CONFIG_IOCTL)
1173 return linereq_set_config(lr, ip);
1174
1175 return -EINVAL;
1176 }
1177
1178 #ifdef CONFIG_COMPAT
linereq_ioctl_compat(struct file * file,unsigned int cmd,unsigned long arg)1179 static long linereq_ioctl_compat(struct file *file, unsigned int cmd,
1180 unsigned long arg)
1181 {
1182 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1183 }
1184 #endif
1185
linereq_poll(struct file * file,struct poll_table_struct * wait)1186 static __poll_t linereq_poll(struct file *file,
1187 struct poll_table_struct *wait)
1188 {
1189 struct linereq *lr = file->private_data;
1190 __poll_t events = 0;
1191
1192 poll_wait(file, &lr->wait, wait);
1193
1194 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events,
1195 &lr->wait.lock))
1196 events = EPOLLIN | EPOLLRDNORM;
1197
1198 return events;
1199 }
1200
linereq_read(struct file * file,char __user * buf,size_t count,loff_t * f_ps)1201 static ssize_t linereq_read(struct file *file,
1202 char __user *buf,
1203 size_t count,
1204 loff_t *f_ps)
1205 {
1206 struct linereq *lr = file->private_data;
1207 struct gpio_v2_line_event le;
1208 ssize_t bytes_read = 0;
1209 int ret;
1210
1211 if (count < sizeof(le))
1212 return -EINVAL;
1213
1214 do {
1215 spin_lock(&lr->wait.lock);
1216 if (kfifo_is_empty(&lr->events)) {
1217 if (bytes_read) {
1218 spin_unlock(&lr->wait.lock);
1219 return bytes_read;
1220 }
1221
1222 if (file->f_flags & O_NONBLOCK) {
1223 spin_unlock(&lr->wait.lock);
1224 return -EAGAIN;
1225 }
1226
1227 ret = wait_event_interruptible_locked(lr->wait,
1228 !kfifo_is_empty(&lr->events));
1229 if (ret) {
1230 spin_unlock(&lr->wait.lock);
1231 return ret;
1232 }
1233 }
1234
1235 ret = kfifo_out(&lr->events, &le, 1);
1236 spin_unlock(&lr->wait.lock);
1237 if (ret != 1) {
1238 /*
1239 * This should never happen - we were holding the
1240 * lock from the moment we learned the fifo is no
1241 * longer empty until now.
1242 */
1243 ret = -EIO;
1244 break;
1245 }
1246
1247 if (copy_to_user(buf + bytes_read, &le, sizeof(le)))
1248 return -EFAULT;
1249 bytes_read += sizeof(le);
1250 } while (count >= bytes_read + sizeof(le));
1251
1252 return bytes_read;
1253 }
1254
linereq_free(struct linereq * lr)1255 static void linereq_free(struct linereq *lr)
1256 {
1257 unsigned int i;
1258
1259 for (i = 0; i < lr->num_lines; i++) {
1260 edge_detector_stop(&lr->lines[i]);
1261 if (lr->lines[i].desc)
1262 gpiod_free(lr->lines[i].desc);
1263 }
1264 kfifo_free(&lr->events);
1265 kfree(lr->label);
1266 put_device(&lr->gdev->dev);
1267 kfree(lr);
1268 }
1269
linereq_release(struct inode * inode,struct file * file)1270 static int linereq_release(struct inode *inode, struct file *file)
1271 {
1272 struct linereq *lr = file->private_data;
1273
1274 linereq_free(lr);
1275 return 0;
1276 }
1277
1278 static const struct file_operations line_fileops = {
1279 .release = linereq_release,
1280 .read = linereq_read,
1281 .poll = linereq_poll,
1282 .owner = THIS_MODULE,
1283 .llseek = noop_llseek,
1284 .unlocked_ioctl = linereq_ioctl,
1285 #ifdef CONFIG_COMPAT
1286 .compat_ioctl = linereq_ioctl_compat,
1287 #endif
1288 };
1289
linereq_create(struct gpio_device * gdev,void __user * ip)1290 static int linereq_create(struct gpio_device *gdev, void __user *ip)
1291 {
1292 struct gpio_v2_line_request ulr;
1293 struct gpio_v2_line_config *lc;
1294 struct linereq *lr;
1295 struct file *file;
1296 u64 flags;
1297 unsigned int i;
1298 int fd, ret;
1299
1300 if (copy_from_user(&ulr, ip, sizeof(ulr)))
1301 return -EFAULT;
1302
1303 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
1304 return -EINVAL;
1305
1306 if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding)))
1307 return -EINVAL;
1308
1309 lc = &ulr.config;
1310 ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
1311 if (ret)
1312 return ret;
1313
1314 lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
1315 if (!lr)
1316 return -ENOMEM;
1317
1318 lr->gdev = gdev;
1319 get_device(&gdev->dev);
1320
1321 for (i = 0; i < ulr.num_lines; i++) {
1322 lr->lines[i].req = lr;
1323 WRITE_ONCE(lr->lines[i].sw_debounced, 0);
1324 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
1325 }
1326
1327 if (ulr.consumer[0] != '\0') {
1328 /* label is only initialized if consumer is set */
1329 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
1330 GFP_KERNEL);
1331 if (!lr->label) {
1332 ret = -ENOMEM;
1333 goto out_free_linereq;
1334 }
1335 }
1336
1337 mutex_init(&lr->config_mutex);
1338 init_waitqueue_head(&lr->wait);
1339 lr->event_buffer_size = ulr.event_buffer_size;
1340 if (lr->event_buffer_size == 0)
1341 lr->event_buffer_size = ulr.num_lines * 16;
1342 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16)
1343 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;
1344
1345 atomic_set(&lr->seqno, 0);
1346 lr->num_lines = ulr.num_lines;
1347
1348 /* Request each GPIO */
1349 for (i = 0; i < ulr.num_lines; i++) {
1350 u32 offset = ulr.offsets[i];
1351 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
1352
1353 if (IS_ERR(desc)) {
1354 ret = PTR_ERR(desc);
1355 goto out_free_linereq;
1356 }
1357
1358 ret = gpiod_request(desc, lr->label);
1359 if (ret)
1360 goto out_free_linereq;
1361
1362 lr->lines[i].desc = desc;
1363 flags = gpio_v2_line_config_flags(lc, i);
1364 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1365
1366 ret = gpiod_set_transitory(desc, false);
1367 if (ret < 0)
1368 goto out_free_linereq;
1369
1370 /*
1371 * Lines have to be requested explicitly for input
1372 * or output, else the line will be treated "as is".
1373 */
1374 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1375 int val = gpio_v2_line_config_output_value(lc, i);
1376
1377 ret = gpiod_direction_output(desc, val);
1378 if (ret)
1379 goto out_free_linereq;
1380 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1381 ret = gpiod_direction_input(desc);
1382 if (ret)
1383 goto out_free_linereq;
1384
1385 ret = edge_detector_setup(&lr->lines[i], lc, i,
1386 flags & GPIO_V2_LINE_EDGE_FLAGS);
1387 if (ret)
1388 goto out_free_linereq;
1389 }
1390
1391 blocking_notifier_call_chain(&desc->gdev->notifier,
1392 GPIO_V2_LINE_CHANGED_REQUESTED, desc);
1393
1394 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
1395 offset);
1396 }
1397
1398 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
1399 if (fd < 0) {
1400 ret = fd;
1401 goto out_free_linereq;
1402 }
1403
1404 file = anon_inode_getfile("gpio-line", &line_fileops, lr,
1405 O_RDONLY | O_CLOEXEC);
1406 if (IS_ERR(file)) {
1407 ret = PTR_ERR(file);
1408 goto out_put_unused_fd;
1409 }
1410
1411 ulr.fd = fd;
1412 if (copy_to_user(ip, &ulr, sizeof(ulr))) {
1413 /*
1414 * fput() will trigger the release() callback, so do not go onto
1415 * the regular error cleanup path here.
1416 */
1417 fput(file);
1418 put_unused_fd(fd);
1419 return -EFAULT;
1420 }
1421
1422 fd_install(fd, file);
1423
1424 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
1425 lr->num_lines);
1426
1427 return 0;
1428
1429 out_put_unused_fd:
1430 put_unused_fd(fd);
1431 out_free_linereq:
1432 linereq_free(lr);
1433 return ret;
1434 }
1435
1436 #ifdef CONFIG_GPIO_CDEV_V1
1437
1438 /*
1439 * GPIO line event management
1440 */
1441
1442 /**
1443 * struct lineevent_state - contains the state of a userspace event
1444 * @gdev: the GPIO device the event pertains to
1445 * @label: consumer label used to tag descriptors
1446 * @desc: the GPIO descriptor held by this event
1447 * @eflags: the event flags this line was requested with
1448 * @irq: the interrupt that trigger in response to events on this GPIO
1449 * @wait: wait queue that handles blocking reads of events
1450 * @events: KFIFO for the GPIO events
1451 * @timestamp: cache for the timestamp storing it between hardirq
1452 * and IRQ thread, used to bring the timestamp close to the actual
1453 * event
1454 */
1455 struct lineevent_state {
1456 struct gpio_device *gdev;
1457 const char *label;
1458 struct gpio_desc *desc;
1459 u32 eflags;
1460 int irq;
1461 wait_queue_head_t wait;
1462 DECLARE_KFIFO(events, struct gpioevent_data, 16);
1463 u64 timestamp;
1464 };
1465
1466 #define GPIOEVENT_REQUEST_VALID_FLAGS \
1467 (GPIOEVENT_REQUEST_RISING_EDGE | \
1468 GPIOEVENT_REQUEST_FALLING_EDGE)
1469
lineevent_poll(struct file * file,struct poll_table_struct * wait)1470 static __poll_t lineevent_poll(struct file *file,
1471 struct poll_table_struct *wait)
1472 {
1473 struct lineevent_state *le = file->private_data;
1474 __poll_t events = 0;
1475
1476 poll_wait(file, &le->wait, wait);
1477
1478 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
1479 events = EPOLLIN | EPOLLRDNORM;
1480
1481 return events;
1482 }
1483
lineevent_get_size(void)1484 static ssize_t lineevent_get_size(void)
1485 {
1486 #if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
1487 /* i386 has no padding after 'id' */
1488 if (in_ia32_syscall()) {
1489 struct compat_gpioeevent_data {
1490 compat_u64 timestamp;
1491 u32 id;
1492 };
1493
1494 return sizeof(struct compat_gpioeevent_data);
1495 }
1496 #endif
1497 return sizeof(struct gpioevent_data);
1498 }
1499
lineevent_read(struct file * file,char __user * buf,size_t count,loff_t * f_ps)1500 static ssize_t lineevent_read(struct file *file,
1501 char __user *buf,
1502 size_t count,
1503 loff_t *f_ps)
1504 {
1505 struct lineevent_state *le = file->private_data;
1506 struct gpioevent_data ge;
1507 ssize_t bytes_read = 0;
1508 ssize_t ge_size;
1509 int ret;
1510
1511 /*
1512 * When compatible system call is being used the struct gpioevent_data,
1513 * in case of at least ia32, has different size due to the alignment
1514 * differences. Because we have first member 64 bits followed by one of
1515 * 32 bits there is no gap between them. The only difference is the
1516 * padding at the end of the data structure. Hence, we calculate the
1517 * actual sizeof() and pass this as an argument to copy_to_user() to
1518 * drop unneeded bytes from the output.
1519 */
1520 ge_size = lineevent_get_size();
1521 if (count < ge_size)
1522 return -EINVAL;
1523
1524 do {
1525 spin_lock(&le->wait.lock);
1526 if (kfifo_is_empty(&le->events)) {
1527 if (bytes_read) {
1528 spin_unlock(&le->wait.lock);
1529 return bytes_read;
1530 }
1531
1532 if (file->f_flags & O_NONBLOCK) {
1533 spin_unlock(&le->wait.lock);
1534 return -EAGAIN;
1535 }
1536
1537 ret = wait_event_interruptible_locked(le->wait,
1538 !kfifo_is_empty(&le->events));
1539 if (ret) {
1540 spin_unlock(&le->wait.lock);
1541 return ret;
1542 }
1543 }
1544
1545 ret = kfifo_out(&le->events, &ge, 1);
1546 spin_unlock(&le->wait.lock);
1547 if (ret != 1) {
1548 /*
1549 * This should never happen - we were holding the lock
1550 * from the moment we learned the fifo is no longer
1551 * empty until now.
1552 */
1553 ret = -EIO;
1554 break;
1555 }
1556
1557 if (copy_to_user(buf + bytes_read, &ge, ge_size))
1558 return -EFAULT;
1559 bytes_read += ge_size;
1560 } while (count >= bytes_read + ge_size);
1561
1562 return bytes_read;
1563 }
1564
lineevent_free(struct lineevent_state * le)1565 static void lineevent_free(struct lineevent_state *le)
1566 {
1567 if (le->irq)
1568 free_irq(le->irq, le);
1569 if (le->desc)
1570 gpiod_free(le->desc);
1571 kfree(le->label);
1572 put_device(&le->gdev->dev);
1573 kfree(le);
1574 }
1575
lineevent_release(struct inode * inode,struct file * file)1576 static int lineevent_release(struct inode *inode, struct file *file)
1577 {
1578 lineevent_free(file->private_data);
1579 return 0;
1580 }
1581
lineevent_ioctl(struct file * file,unsigned int cmd,unsigned long arg)1582 static long lineevent_ioctl(struct file *file, unsigned int cmd,
1583 unsigned long arg)
1584 {
1585 struct lineevent_state *le = file->private_data;
1586 void __user *ip = (void __user *)arg;
1587 struct gpiohandle_data ghd;
1588
1589 /*
1590 * We can get the value for an event line but not set it,
1591 * because it is input by definition.
1592 */
1593 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
1594 int val;
1595
1596 memset(&ghd, 0, sizeof(ghd));
1597
1598 val = gpiod_get_value_cansleep(le->desc);
1599 if (val < 0)
1600 return val;
1601 ghd.values[0] = val;
1602
1603 if (copy_to_user(ip, &ghd, sizeof(ghd)))
1604 return -EFAULT;
1605
1606 return 0;
1607 }
1608 return -EINVAL;
1609 }
1610
1611 #ifdef CONFIG_COMPAT
lineevent_ioctl_compat(struct file * file,unsigned int cmd,unsigned long arg)1612 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd,
1613 unsigned long arg)
1614 {
1615 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1616 }
1617 #endif
1618
1619 static const struct file_operations lineevent_fileops = {
1620 .release = lineevent_release,
1621 .read = lineevent_read,
1622 .poll = lineevent_poll,
1623 .owner = THIS_MODULE,
1624 .llseek = noop_llseek,
1625 .unlocked_ioctl = lineevent_ioctl,
1626 #ifdef CONFIG_COMPAT
1627 .compat_ioctl = lineevent_ioctl_compat,
1628 #endif
1629 };
1630
lineevent_irq_thread(int irq,void * p)1631 static irqreturn_t lineevent_irq_thread(int irq, void *p)
1632 {
1633 struct lineevent_state *le = p;
1634 struct gpioevent_data ge;
1635 int ret;
1636
1637 /* Do not leak kernel stack to userspace */
1638 memset(&ge, 0, sizeof(ge));
1639
1640 /*
1641 * We may be running from a nested threaded interrupt in which case
1642 * we didn't get the timestamp from lineevent_irq_handler().
1643 */
1644 if (!le->timestamp)
1645 ge.timestamp = ktime_get_ns();
1646 else
1647 ge.timestamp = le->timestamp;
1648
1649 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
1650 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
1651 int level = gpiod_get_value_cansleep(le->desc);
1652
1653 if (level)
1654 /* Emit low-to-high event */
1655 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
1656 else
1657 /* Emit high-to-low event */
1658 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
1659 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
1660 /* Emit low-to-high event */
1661 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
1662 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
1663 /* Emit high-to-low event */
1664 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
1665 } else {
1666 return IRQ_NONE;
1667 }
1668
1669 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
1670 1, &le->wait.lock);
1671 if (ret)
1672 wake_up_poll(&le->wait, EPOLLIN);
1673 else
1674 pr_debug_ratelimited("event FIFO is full - event dropped\n");
1675
1676 return IRQ_HANDLED;
1677 }
1678
lineevent_irq_handler(int irq,void * p)1679 static irqreturn_t lineevent_irq_handler(int irq, void *p)
1680 {
1681 struct lineevent_state *le = p;
1682
1683 /*
1684 * Just store the timestamp in hardirq context so we get it as
1685 * close in time as possible to the actual event.
1686 */
1687 le->timestamp = ktime_get_ns();
1688
1689 return IRQ_WAKE_THREAD;
1690 }
1691
lineevent_create(struct gpio_device * gdev,void __user * ip)1692 static int lineevent_create(struct gpio_device *gdev, void __user *ip)
1693 {
1694 struct gpioevent_request eventreq;
1695 struct lineevent_state *le;
1696 struct gpio_desc *desc;
1697 struct file *file;
1698 u32 offset;
1699 u32 lflags;
1700 u32 eflags;
1701 int fd;
1702 int ret;
1703 int irq, irqflags = 0;
1704
1705 if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
1706 return -EFAULT;
1707
1708 offset = eventreq.lineoffset;
1709 lflags = eventreq.handleflags;
1710 eflags = eventreq.eventflags;
1711
1712 desc = gpiochip_get_desc(gdev->chip, offset);
1713 if (IS_ERR(desc))
1714 return PTR_ERR(desc);
1715
1716 /* Return an error if a unknown flag is set */
1717 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
1718 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
1719 return -EINVAL;
1720
1721 /* This is just wrong: we don't look for events on output lines */
1722 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
1723 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
1724 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
1725 return -EINVAL;
1726
1727 /* Only one bias flag can be set. */
1728 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
1729 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
1730 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
1731 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
1732 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
1733 return -EINVAL;
1734
1735 le = kzalloc(sizeof(*le), GFP_KERNEL);
1736 if (!le)
1737 return -ENOMEM;
1738 le->gdev = gdev;
1739 get_device(&gdev->dev);
1740
1741 if (eventreq.consumer_label[0] != '\0') {
1742 /* label is only initialized if consumer_label is set */
1743 le->label = kstrndup(eventreq.consumer_label,
1744 sizeof(eventreq.consumer_label) - 1,
1745 GFP_KERNEL);
1746 if (!le->label) {
1747 ret = -ENOMEM;
1748 goto out_free_le;
1749 }
1750 }
1751
1752 ret = gpiod_request(desc, le->label);
1753 if (ret)
1754 goto out_free_le;
1755 le->desc = desc;
1756 le->eflags = eflags;
1757
1758 linehandle_flags_to_desc_flags(lflags, &desc->flags);
1759
1760 ret = gpiod_direction_input(desc);
1761 if (ret)
1762 goto out_free_le;
1763
1764 blocking_notifier_call_chain(&desc->gdev->notifier,
1765 GPIO_V2_LINE_CHANGED_REQUESTED, desc);
1766
1767 irq = gpiod_to_irq(desc);
1768 if (irq <= 0) {
1769 ret = -ENODEV;
1770 goto out_free_le;
1771 }
1772
1773 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
1774 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
1775 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
1776 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
1777 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
1778 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
1779 irqflags |= IRQF_ONESHOT;
1780
1781 INIT_KFIFO(le->events);
1782 init_waitqueue_head(&le->wait);
1783
1784 /* Request a thread to read the events */
1785 ret = request_threaded_irq(irq,
1786 lineevent_irq_handler,
1787 lineevent_irq_thread,
1788 irqflags,
1789 le->label,
1790 le);
1791 if (ret)
1792 goto out_free_le;
1793
1794 le->irq = irq;
1795
1796 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
1797 if (fd < 0) {
1798 ret = fd;
1799 goto out_free_le;
1800 }
1801
1802 file = anon_inode_getfile("gpio-event",
1803 &lineevent_fileops,
1804 le,
1805 O_RDONLY | O_CLOEXEC);
1806 if (IS_ERR(file)) {
1807 ret = PTR_ERR(file);
1808 goto out_put_unused_fd;
1809 }
1810
1811 eventreq.fd = fd;
1812 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) {
1813 /*
1814 * fput() will trigger the release() callback, so do not go onto
1815 * the regular error cleanup path here.
1816 */
1817 fput(file);
1818 put_unused_fd(fd);
1819 return -EFAULT;
1820 }
1821
1822 fd_install(fd, file);
1823
1824 return 0;
1825
1826 out_put_unused_fd:
1827 put_unused_fd(fd);
1828 out_free_le:
1829 lineevent_free(le);
1830 return ret;
1831 }
1832
gpio_v2_line_info_to_v1(struct gpio_v2_line_info * info_v2,struct gpioline_info * info_v1)1833 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2,
1834 struct gpioline_info *info_v1)
1835 {
1836 u64 flagsv2 = info_v2->flags;
1837
1838 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name));
1839 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer));
1840 info_v1->line_offset = info_v2->offset;
1841 info_v1->flags = 0;
1842
1843 if (flagsv2 & GPIO_V2_LINE_FLAG_USED)
1844 info_v1->flags |= GPIOLINE_FLAG_KERNEL;
1845
1846 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT)
1847 info_v1->flags |= GPIOLINE_FLAG_IS_OUT;
1848
1849 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
1850 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
1851
1852 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN)
1853 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN;
1854 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE)
1855 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE;
1856
1857 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)
1858 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
1859 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN)
1860 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
1861 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED)
1862 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
1863 }
1864
gpio_v2_line_info_changed_to_v1(struct gpio_v2_line_info_changed * lic_v2,struct gpioline_info_changed * lic_v1)1865 static void gpio_v2_line_info_changed_to_v1(
1866 struct gpio_v2_line_info_changed *lic_v2,
1867 struct gpioline_info_changed *lic_v1)
1868 {
1869 memset(lic_v1, 0, sizeof(*lic_v1));
1870 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info);
1871 lic_v1->timestamp = lic_v2->timestamp_ns;
1872 lic_v1->event_type = lic_v2->event_type;
1873 }
1874
1875 #endif /* CONFIG_GPIO_CDEV_V1 */
1876
gpio_desc_to_lineinfo(struct gpio_desc * desc,struct gpio_v2_line_info * info)1877 static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
1878 struct gpio_v2_line_info *info)
1879 {
1880 struct gpio_chip *gc = desc->gdev->chip;
1881 bool ok_for_pinctrl;
1882 unsigned long flags;
1883 u32 debounce_period_us;
1884 unsigned int num_attrs = 0;
1885
1886 memset(info, 0, sizeof(*info));
1887 info->offset = gpio_chip_hwgpio(desc);
1888
1889 /*
1890 * This function takes a mutex so we must check this before taking
1891 * the spinlock.
1892 *
1893 * FIXME: find a non-racy way to retrieve this information. Maybe a
1894 * lock common to both frameworks?
1895 */
1896 ok_for_pinctrl =
1897 pinctrl_gpio_can_use_line(gc->base + info->offset);
1898
1899 spin_lock_irqsave(&gpio_lock, flags);
1900
1901 if (desc->name)
1902 strscpy(info->name, desc->name, sizeof(info->name));
1903
1904 if (desc->label)
1905 strscpy(info->consumer, desc->label, sizeof(info->consumer));
1906
1907 /*
1908 * Userspace only need to know that the kernel is using this GPIO so
1909 * it can't use it.
1910 */
1911 info->flags = 0;
1912 if (test_bit(FLAG_REQUESTED, &desc->flags) ||
1913 test_bit(FLAG_IS_HOGGED, &desc->flags) ||
1914 test_bit(FLAG_USED_AS_IRQ, &desc->flags) ||
1915 test_bit(FLAG_EXPORT, &desc->flags) ||
1916 test_bit(FLAG_SYSFS, &desc->flags) ||
1917 !ok_for_pinctrl)
1918 info->flags |= GPIO_V2_LINE_FLAG_USED;
1919
1920 if (test_bit(FLAG_IS_OUT, &desc->flags))
1921 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
1922 else
1923 info->flags |= GPIO_V2_LINE_FLAG_INPUT;
1924
1925 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1926 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
1927
1928 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
1929 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
1930 if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
1931 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
1932
1933 if (test_bit(FLAG_BIAS_DISABLE, &desc->flags))
1934 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
1935 if (test_bit(FLAG_PULL_DOWN, &desc->flags))
1936 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
1937 if (test_bit(FLAG_PULL_UP, &desc->flags))
1938 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
1939
1940 if (test_bit(FLAG_EDGE_RISING, &desc->flags))
1941 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
1942 if (test_bit(FLAG_EDGE_FALLING, &desc->flags))
1943 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
1944
1945 debounce_period_us = READ_ONCE(desc->debounce_period_us);
1946 if (debounce_period_us) {
1947 info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
1948 info->attrs[num_attrs].debounce_period_us = debounce_period_us;
1949 num_attrs++;
1950 }
1951 info->num_attrs = num_attrs;
1952
1953 spin_unlock_irqrestore(&gpio_lock, flags);
1954 }
1955
1956 struct gpio_chardev_data {
1957 struct gpio_device *gdev;
1958 wait_queue_head_t wait;
1959 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32);
1960 struct notifier_block lineinfo_changed_nb;
1961 unsigned long *watched_lines;
1962 #ifdef CONFIG_GPIO_CDEV_V1
1963 atomic_t watch_abi_version;
1964 #endif
1965 };
1966
chipinfo_get(struct gpio_chardev_data * cdev,void __user * ip)1967 static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip)
1968 {
1969 struct gpio_device *gdev = cdev->gdev;
1970 struct gpiochip_info chipinfo;
1971
1972 memset(&chipinfo, 0, sizeof(chipinfo));
1973
1974 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name));
1975 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label));
1976 chipinfo.lines = gdev->ngpio;
1977 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
1978 return -EFAULT;
1979 return 0;
1980 }
1981
1982 #ifdef CONFIG_GPIO_CDEV_V1
1983 /*
1984 * returns 0 if the versions match, else the previously selected ABI version
1985 */
lineinfo_ensure_abi_version(struct gpio_chardev_data * cdata,unsigned int version)1986 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata,
1987 unsigned int version)
1988 {
1989 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version);
1990
1991 if (abiv == version)
1992 return 0;
1993
1994 return abiv;
1995 }
1996
lineinfo_get_v1(struct gpio_chardev_data * cdev,void __user * ip,bool watch)1997 static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
1998 bool watch)
1999 {
2000 struct gpio_desc *desc;
2001 struct gpioline_info lineinfo;
2002 struct gpio_v2_line_info lineinfo_v2;
2003
2004 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2005 return -EFAULT;
2006
2007 /* this doubles as a range check on line_offset */
2008 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset);
2009 if (IS_ERR(desc))
2010 return PTR_ERR(desc);
2011
2012 if (watch) {
2013 if (lineinfo_ensure_abi_version(cdev, 1))
2014 return -EPERM;
2015
2016 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
2017 return -EBUSY;
2018 }
2019
2020 gpio_desc_to_lineinfo(desc, &lineinfo_v2);
2021 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
2022
2023 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2024 if (watch)
2025 clear_bit(lineinfo.line_offset, cdev->watched_lines);
2026 return -EFAULT;
2027 }
2028
2029 return 0;
2030 }
2031 #endif
2032
lineinfo_get(struct gpio_chardev_data * cdev,void __user * ip,bool watch)2033 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
2034 bool watch)
2035 {
2036 struct gpio_desc *desc;
2037 struct gpio_v2_line_info lineinfo;
2038
2039 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2040 return -EFAULT;
2041
2042 if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding)))
2043 return -EINVAL;
2044
2045 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset);
2046 if (IS_ERR(desc))
2047 return PTR_ERR(desc);
2048
2049 if (watch) {
2050 #ifdef CONFIG_GPIO_CDEV_V1
2051 if (lineinfo_ensure_abi_version(cdev, 2))
2052 return -EPERM;
2053 #endif
2054 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
2055 return -EBUSY;
2056 }
2057 gpio_desc_to_lineinfo(desc, &lineinfo);
2058
2059 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2060 if (watch)
2061 clear_bit(lineinfo.offset, cdev->watched_lines);
2062 return -EFAULT;
2063 }
2064
2065 return 0;
2066 }
2067
lineinfo_unwatch(struct gpio_chardev_data * cdev,void __user * ip)2068 static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip)
2069 {
2070 __u32 offset;
2071
2072 if (copy_from_user(&offset, ip, sizeof(offset)))
2073 return -EFAULT;
2074
2075 if (offset >= cdev->gdev->ngpio)
2076 return -EINVAL;
2077
2078 if (!test_and_clear_bit(offset, cdev->watched_lines))
2079 return -EBUSY;
2080
2081 return 0;
2082 }
2083
2084 /*
2085 * gpio_ioctl() - ioctl handler for the GPIO chardev
2086 */
gpio_ioctl(struct file * file,unsigned int cmd,unsigned long arg)2087 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2088 {
2089 struct gpio_chardev_data *cdev = file->private_data;
2090 struct gpio_device *gdev = cdev->gdev;
2091 void __user *ip = (void __user *)arg;
2092
2093 /* We fail any subsequent ioctl():s when the chip is gone */
2094 if (!gdev->chip)
2095 return -ENODEV;
2096
2097 /* Fill in the struct and pass to userspace */
2098 if (cmd == GPIO_GET_CHIPINFO_IOCTL) {
2099 return chipinfo_get(cdev, ip);
2100 #ifdef CONFIG_GPIO_CDEV_V1
2101 } else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) {
2102 return linehandle_create(gdev, ip);
2103 } else if (cmd == GPIO_GET_LINEEVENT_IOCTL) {
2104 return lineevent_create(gdev, ip);
2105 } else if (cmd == GPIO_GET_LINEINFO_IOCTL ||
2106 cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) {
2107 return lineinfo_get_v1(cdev, ip,
2108 cmd == GPIO_GET_LINEINFO_WATCH_IOCTL);
2109 #endif /* CONFIG_GPIO_CDEV_V1 */
2110 } else if (cmd == GPIO_V2_GET_LINEINFO_IOCTL ||
2111 cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL) {
2112 return lineinfo_get(cdev, ip,
2113 cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL);
2114 } else if (cmd == GPIO_V2_GET_LINE_IOCTL) {
2115 return linereq_create(gdev, ip);
2116 } else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) {
2117 return lineinfo_unwatch(cdev, ip);
2118 }
2119 return -EINVAL;
2120 }
2121
2122 #ifdef CONFIG_COMPAT
gpio_ioctl_compat(struct file * file,unsigned int cmd,unsigned long arg)2123 static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
2124 unsigned long arg)
2125 {
2126 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2127 }
2128 #endif
2129
2130 static struct gpio_chardev_data *
to_gpio_chardev_data(struct notifier_block * nb)2131 to_gpio_chardev_data(struct notifier_block *nb)
2132 {
2133 return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
2134 }
2135
lineinfo_changed_notify(struct notifier_block * nb,unsigned long action,void * data)2136 static int lineinfo_changed_notify(struct notifier_block *nb,
2137 unsigned long action, void *data)
2138 {
2139 struct gpio_chardev_data *cdev = to_gpio_chardev_data(nb);
2140 struct gpio_v2_line_info_changed chg;
2141 struct gpio_desc *desc = data;
2142 int ret;
2143
2144 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines))
2145 return NOTIFY_DONE;
2146
2147 memset(&chg, 0, sizeof(chg));
2148 chg.event_type = action;
2149 chg.timestamp_ns = ktime_get_ns();
2150 gpio_desc_to_lineinfo(desc, &chg.info);
2151
2152 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
2153 if (ret)
2154 wake_up_poll(&cdev->wait, EPOLLIN);
2155 else
2156 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");
2157
2158 return NOTIFY_OK;
2159 }
2160
lineinfo_watch_poll(struct file * file,struct poll_table_struct * pollt)2161 static __poll_t lineinfo_watch_poll(struct file *file,
2162 struct poll_table_struct *pollt)
2163 {
2164 struct gpio_chardev_data *cdev = file->private_data;
2165 __poll_t events = 0;
2166
2167 poll_wait(file, &cdev->wait, pollt);
2168
2169 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events,
2170 &cdev->wait.lock))
2171 events = EPOLLIN | EPOLLRDNORM;
2172
2173 return events;
2174 }
2175
lineinfo_watch_read(struct file * file,char __user * buf,size_t count,loff_t * off)2176 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
2177 size_t count, loff_t *off)
2178 {
2179 struct gpio_chardev_data *cdev = file->private_data;
2180 struct gpio_v2_line_info_changed event;
2181 ssize_t bytes_read = 0;
2182 int ret;
2183 size_t event_size;
2184
2185 #ifndef CONFIG_GPIO_CDEV_V1
2186 event_size = sizeof(struct gpio_v2_line_info_changed);
2187 if (count < event_size)
2188 return -EINVAL;
2189 #endif
2190
2191 do {
2192 spin_lock(&cdev->wait.lock);
2193 if (kfifo_is_empty(&cdev->events)) {
2194 if (bytes_read) {
2195 spin_unlock(&cdev->wait.lock);
2196 return bytes_read;
2197 }
2198
2199 if (file->f_flags & O_NONBLOCK) {
2200 spin_unlock(&cdev->wait.lock);
2201 return -EAGAIN;
2202 }
2203
2204 ret = wait_event_interruptible_locked(cdev->wait,
2205 !kfifo_is_empty(&cdev->events));
2206 if (ret) {
2207 spin_unlock(&cdev->wait.lock);
2208 return ret;
2209 }
2210 }
2211 #ifdef CONFIG_GPIO_CDEV_V1
2212 /* must be after kfifo check so watch_abi_version is set */
2213 if (atomic_read(&cdev->watch_abi_version) == 2)
2214 event_size = sizeof(struct gpio_v2_line_info_changed);
2215 else
2216 event_size = sizeof(struct gpioline_info_changed);
2217 if (count < event_size) {
2218 spin_unlock(&cdev->wait.lock);
2219 return -EINVAL;
2220 }
2221 #endif
2222 ret = kfifo_out(&cdev->events, &event, 1);
2223 spin_unlock(&cdev->wait.lock);
2224 if (ret != 1) {
2225 ret = -EIO;
2226 break;
2227 /* We should never get here. See lineevent_read(). */
2228 }
2229
2230 #ifdef CONFIG_GPIO_CDEV_V1
2231 if (event_size == sizeof(struct gpio_v2_line_info_changed)) {
2232 if (copy_to_user(buf + bytes_read, &event, event_size))
2233 return -EFAULT;
2234 } else {
2235 struct gpioline_info_changed event_v1;
2236
2237 gpio_v2_line_info_changed_to_v1(&event, &event_v1);
2238 if (copy_to_user(buf + bytes_read, &event_v1,
2239 event_size))
2240 return -EFAULT;
2241 }
2242 #else
2243 if (copy_to_user(buf + bytes_read, &event, event_size))
2244 return -EFAULT;
2245 #endif
2246 bytes_read += event_size;
2247 } while (count >= bytes_read + sizeof(event));
2248
2249 return bytes_read;
2250 }
2251
2252 /**
2253 * gpio_chrdev_open() - open the chardev for ioctl operations
2254 * @inode: inode for this chardev
2255 * @file: file struct for storing private data
2256 * Returns 0 on success
2257 */
gpio_chrdev_open(struct inode * inode,struct file * file)2258 static int gpio_chrdev_open(struct inode *inode, struct file *file)
2259 {
2260 struct gpio_device *gdev = container_of(inode->i_cdev,
2261 struct gpio_device, chrdev);
2262 struct gpio_chardev_data *cdev;
2263 int ret = -ENOMEM;
2264
2265 /* Fail on open if the backing gpiochip is gone */
2266 if (!gdev->chip)
2267 return -ENODEV;
2268
2269 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
2270 if (!cdev)
2271 return -ENOMEM;
2272
2273 cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL);
2274 if (!cdev->watched_lines)
2275 goto out_free_cdev;
2276
2277 init_waitqueue_head(&cdev->wait);
2278 INIT_KFIFO(cdev->events);
2279 cdev->gdev = gdev;
2280
2281 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
2282 ret = blocking_notifier_chain_register(&gdev->notifier,
2283 &cdev->lineinfo_changed_nb);
2284 if (ret)
2285 goto out_free_bitmap;
2286
2287 get_device(&gdev->dev);
2288 file->private_data = cdev;
2289
2290 ret = nonseekable_open(inode, file);
2291 if (ret)
2292 goto out_unregister_notifier;
2293
2294 return ret;
2295
2296 out_unregister_notifier:
2297 blocking_notifier_chain_unregister(&gdev->notifier,
2298 &cdev->lineinfo_changed_nb);
2299 out_free_bitmap:
2300 bitmap_free(cdev->watched_lines);
2301 out_free_cdev:
2302 kfree(cdev);
2303 return ret;
2304 }
2305
2306 /**
2307 * gpio_chrdev_release() - close chardev after ioctl operations
2308 * @inode: inode for this chardev
2309 * @file: file struct for storing private data
2310 * Returns 0 on success
2311 */
gpio_chrdev_release(struct inode * inode,struct file * file)2312 static int gpio_chrdev_release(struct inode *inode, struct file *file)
2313 {
2314 struct gpio_chardev_data *cdev = file->private_data;
2315 struct gpio_device *gdev = cdev->gdev;
2316
2317 bitmap_free(cdev->watched_lines);
2318 blocking_notifier_chain_unregister(&gdev->notifier,
2319 &cdev->lineinfo_changed_nb);
2320 put_device(&gdev->dev);
2321 kfree(cdev);
2322
2323 return 0;
2324 }
2325
2326 static const struct file_operations gpio_fileops = {
2327 .release = gpio_chrdev_release,
2328 .open = gpio_chrdev_open,
2329 .poll = lineinfo_watch_poll,
2330 .read = lineinfo_watch_read,
2331 .owner = THIS_MODULE,
2332 .llseek = no_llseek,
2333 .unlocked_ioctl = gpio_ioctl,
2334 #ifdef CONFIG_COMPAT
2335 .compat_ioctl = gpio_ioctl_compat,
2336 #endif
2337 };
2338
gpiolib_cdev_register(struct gpio_device * gdev,dev_t devt)2339 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
2340 {
2341 int ret;
2342
2343 cdev_init(&gdev->chrdev, &gpio_fileops);
2344 gdev->chrdev.owner = THIS_MODULE;
2345 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
2346
2347 ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
2348 if (ret)
2349 return ret;
2350
2351 chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
2352 MAJOR(devt), gdev->id);
2353
2354 return 0;
2355 }
2356
gpiolib_cdev_unregister(struct gpio_device * gdev)2357 void gpiolib_cdev_unregister(struct gpio_device *gdev)
2358 {
2359 cdev_device_del(&gdev->chrdev, &gdev->dev);
2360 }
2361