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