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/hte.h>
16 #include <linux/interrupt.h>
17 #include <linux/irqreturn.h>
18 #include <linux/kernel.h>
19 #include <linux/kfifo.h>
20 #include <linux/module.h>
21 #include <linux/mutex.h>
22 #include <linux/pinctrl/consumer.h>
23 #include <linux/poll.h>
24 #include <linux/seq_file.h>
25 #include <linux/spinlock.h>
26 #include <linux/timekeeping.h>
27 #include <linux/uaccess.h>
28 #include <linux/workqueue.h>
29
30 #include <uapi/linux/gpio.h>
31
32 #include "gpiolib.h"
33 #include "gpiolib-cdev.h"
34
35 /*
36 * Array sizes must ensure 64-bit alignment and not create holes in the
37 * struct packing.
38 */
39 static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2));
40 static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8));
41
42 /*
43 * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility
44 */
45 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8));
46 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8));
47 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8));
48 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8));
49 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8));
50 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8));
51 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8));
52 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8));
53
54 /* Character device interface to GPIO.
55 *
56 * The GPIO character device, /dev/gpiochipN, provides userspace an
57 * interface to gpiolib GPIOs via ioctl()s.
58 */
59
60 typedef __poll_t (*poll_fn)(struct file *, struct poll_table_struct *);
61 typedef long (*ioctl_fn)(struct file *, unsigned int, unsigned long);
62 typedef ssize_t (*read_fn)(struct file *, char __user *,
63 size_t count, loff_t *);
64
call_poll_locked(struct file * file,struct poll_table_struct * wait,struct gpio_device * gdev,poll_fn func)65 static __poll_t call_poll_locked(struct file *file,
66 struct poll_table_struct *wait,
67 struct gpio_device *gdev, poll_fn func)
68 {
69 __poll_t ret;
70
71 down_read(&gdev->sem);
72 ret = func(file, wait);
73 up_read(&gdev->sem);
74
75 return ret;
76 }
77
call_ioctl_locked(struct file * file,unsigned int cmd,unsigned long arg,struct gpio_device * gdev,ioctl_fn func)78 static long call_ioctl_locked(struct file *file, unsigned int cmd,
79 unsigned long arg, struct gpio_device *gdev,
80 ioctl_fn func)
81 {
82 long ret;
83
84 down_read(&gdev->sem);
85 ret = func(file, cmd, arg);
86 up_read(&gdev->sem);
87
88 return ret;
89 }
90
call_read_locked(struct file * file,char __user * buf,size_t count,loff_t * f_ps,struct gpio_device * gdev,read_fn func)91 static ssize_t call_read_locked(struct file *file, char __user *buf,
92 size_t count, loff_t *f_ps,
93 struct gpio_device *gdev, read_fn func)
94 {
95 ssize_t ret;
96
97 down_read(&gdev->sem);
98 ret = func(file, buf, count, f_ps);
99 up_read(&gdev->sem);
100
101 return ret;
102 }
103
104 /*
105 * GPIO line handle management
106 */
107
108 #ifdef CONFIG_GPIO_CDEV_V1
109 /**
110 * struct linehandle_state - contains the state of a userspace handle
111 * @gdev: the GPIO device the handle pertains to
112 * @label: consumer label used to tag descriptors
113 * @descs: the GPIO descriptors held by this handle
114 * @num_descs: the number of descriptors held in the descs array
115 */
116 struct linehandle_state {
117 struct gpio_device *gdev;
118 const char *label;
119 struct gpio_desc *descs[GPIOHANDLES_MAX];
120 u32 num_descs;
121 };
122
123 #define GPIOHANDLE_REQUEST_VALID_FLAGS \
124 (GPIOHANDLE_REQUEST_INPUT | \
125 GPIOHANDLE_REQUEST_OUTPUT | \
126 GPIOHANDLE_REQUEST_ACTIVE_LOW | \
127 GPIOHANDLE_REQUEST_BIAS_PULL_UP | \
128 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \
129 GPIOHANDLE_REQUEST_BIAS_DISABLE | \
130 GPIOHANDLE_REQUEST_OPEN_DRAIN | \
131 GPIOHANDLE_REQUEST_OPEN_SOURCE)
132
linehandle_validate_flags(u32 flags)133 static int linehandle_validate_flags(u32 flags)
134 {
135 /* Return an error if an unknown flag is set */
136 if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
137 return -EINVAL;
138
139 /*
140 * Do not allow both INPUT & OUTPUT flags to be set as they are
141 * contradictory.
142 */
143 if ((flags & GPIOHANDLE_REQUEST_INPUT) &&
144 (flags & GPIOHANDLE_REQUEST_OUTPUT))
145 return -EINVAL;
146
147 /*
148 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
149 * the hardware actually supports enabling both at the same time the
150 * electrical result would be disastrous.
151 */
152 if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
153 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
154 return -EINVAL;
155
156 /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
157 if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) &&
158 ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
159 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
160 return -EINVAL;
161
162 /* Bias flags only allowed for input or output mode. */
163 if (!((flags & GPIOHANDLE_REQUEST_INPUT) ||
164 (flags & GPIOHANDLE_REQUEST_OUTPUT)) &&
165 ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) ||
166 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) ||
167 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
168 return -EINVAL;
169
170 /* Only one bias flag can be set. */
171 if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
172 (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
173 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
174 ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
175 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
176 return -EINVAL;
177
178 return 0;
179 }
180
linehandle_flags_to_desc_flags(u32 lflags,unsigned long * flagsp)181 static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp)
182 {
183 assign_bit(FLAG_ACTIVE_LOW, flagsp,
184 lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
185 assign_bit(FLAG_OPEN_DRAIN, flagsp,
186 lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
187 assign_bit(FLAG_OPEN_SOURCE, flagsp,
188 lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
189 assign_bit(FLAG_PULL_UP, flagsp,
190 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
191 assign_bit(FLAG_PULL_DOWN, flagsp,
192 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
193 assign_bit(FLAG_BIAS_DISABLE, flagsp,
194 lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
195 }
196
linehandle_set_config(struct linehandle_state * lh,void __user * ip)197 static long linehandle_set_config(struct linehandle_state *lh,
198 void __user *ip)
199 {
200 struct gpiohandle_config gcnf;
201 struct gpio_desc *desc;
202 int i, ret;
203 u32 lflags;
204
205 if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
206 return -EFAULT;
207
208 lflags = gcnf.flags;
209 ret = linehandle_validate_flags(lflags);
210 if (ret)
211 return ret;
212
213 for (i = 0; i < lh->num_descs; i++) {
214 desc = lh->descs[i];
215 linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags);
216
217 /*
218 * Lines have to be requested explicitly for input
219 * or output, else the line will be treated "as is".
220 */
221 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
222 int val = !!gcnf.default_values[i];
223
224 ret = gpiod_direction_output(desc, val);
225 if (ret)
226 return ret;
227 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
228 ret = gpiod_direction_input(desc);
229 if (ret)
230 return ret;
231 }
232
233 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
234 }
235 return 0;
236 }
237
linehandle_ioctl_unlocked(struct file * file,unsigned int cmd,unsigned long arg)238 static long linehandle_ioctl_unlocked(struct file *file, unsigned int cmd,
239 unsigned long arg)
240 {
241 struct linehandle_state *lh = file->private_data;
242 void __user *ip = (void __user *)arg;
243 struct gpiohandle_data ghd;
244 DECLARE_BITMAP(vals, GPIOHANDLES_MAX);
245 unsigned int i;
246 int ret;
247
248 if (!lh->gdev->chip)
249 return -ENODEV;
250
251 switch (cmd) {
252 case GPIOHANDLE_GET_LINE_VALUES_IOCTL:
253 /* NOTE: It's okay to read values of output lines */
254 ret = gpiod_get_array_value_complex(false, true,
255 lh->num_descs, lh->descs,
256 NULL, vals);
257 if (ret)
258 return ret;
259
260 memset(&ghd, 0, sizeof(ghd));
261 for (i = 0; i < lh->num_descs; i++)
262 ghd.values[i] = test_bit(i, vals);
263
264 if (copy_to_user(ip, &ghd, sizeof(ghd)))
265 return -EFAULT;
266
267 return 0;
268 case GPIOHANDLE_SET_LINE_VALUES_IOCTL:
269 /*
270 * All line descriptors were created at once with the same
271 * flags so just check if the first one is really output.
272 */
273 if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags))
274 return -EPERM;
275
276 if (copy_from_user(&ghd, ip, sizeof(ghd)))
277 return -EFAULT;
278
279 /* Clamp all values to [0,1] */
280 for (i = 0; i < lh->num_descs; i++)
281 __assign_bit(i, vals, ghd.values[i]);
282
283 /* Reuse the array setting function */
284 return gpiod_set_array_value_complex(false,
285 true,
286 lh->num_descs,
287 lh->descs,
288 NULL,
289 vals);
290 case GPIOHANDLE_SET_CONFIG_IOCTL:
291 return linehandle_set_config(lh, ip);
292 default:
293 return -EINVAL;
294 }
295 }
296
linehandle_ioctl(struct file * file,unsigned int cmd,unsigned long arg)297 static long linehandle_ioctl(struct file *file, unsigned int cmd,
298 unsigned long arg)
299 {
300 struct linehandle_state *lh = file->private_data;
301
302 return call_ioctl_locked(file, cmd, arg, lh->gdev,
303 linehandle_ioctl_unlocked);
304 }
305
306 #ifdef CONFIG_COMPAT
linehandle_ioctl_compat(struct file * file,unsigned int cmd,unsigned long arg)307 static long linehandle_ioctl_compat(struct file *file, unsigned int cmd,
308 unsigned long arg)
309 {
310 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
311 }
312 #endif
313
linehandle_free(struct linehandle_state * lh)314 static void linehandle_free(struct linehandle_state *lh)
315 {
316 int i;
317
318 for (i = 0; i < lh->num_descs; i++)
319 if (lh->descs[i])
320 gpiod_free(lh->descs[i]);
321 kfree(lh->label);
322 gpio_device_put(lh->gdev);
323 kfree(lh);
324 }
325
linehandle_release(struct inode * inode,struct file * file)326 static int linehandle_release(struct inode *inode, struct file *file)
327 {
328 linehandle_free(file->private_data);
329 return 0;
330 }
331
332 static const struct file_operations linehandle_fileops = {
333 .release = linehandle_release,
334 .owner = THIS_MODULE,
335 .llseek = noop_llseek,
336 .unlocked_ioctl = linehandle_ioctl,
337 #ifdef CONFIG_COMPAT
338 .compat_ioctl = linehandle_ioctl_compat,
339 #endif
340 };
341
linehandle_create(struct gpio_device * gdev,void __user * ip)342 static int linehandle_create(struct gpio_device *gdev, void __user *ip)
343 {
344 struct gpiohandle_request handlereq;
345 struct linehandle_state *lh;
346 struct file *file;
347 int fd, i, ret;
348 u32 lflags;
349
350 if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
351 return -EFAULT;
352 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
353 return -EINVAL;
354
355 lflags = handlereq.flags;
356
357 ret = linehandle_validate_flags(lflags);
358 if (ret)
359 return ret;
360
361 lh = kzalloc(sizeof(*lh), GFP_KERNEL);
362 if (!lh)
363 return -ENOMEM;
364 lh->gdev = gpio_device_get(gdev);
365
366 if (handlereq.consumer_label[0] != '\0') {
367 /* label is only initialized if consumer_label is set */
368 lh->label = kstrndup(handlereq.consumer_label,
369 sizeof(handlereq.consumer_label) - 1,
370 GFP_KERNEL);
371 if (!lh->label) {
372 ret = -ENOMEM;
373 goto out_free_lh;
374 }
375 }
376
377 lh->num_descs = handlereq.lines;
378
379 /* Request each GPIO */
380 for (i = 0; i < handlereq.lines; i++) {
381 u32 offset = handlereq.lineoffsets[i];
382 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
383
384 if (IS_ERR(desc)) {
385 ret = PTR_ERR(desc);
386 goto out_free_lh;
387 }
388
389 ret = gpiod_request_user(desc, lh->label);
390 if (ret)
391 goto out_free_lh;
392 lh->descs[i] = desc;
393 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);
394
395 ret = gpiod_set_transitory(desc, false);
396 if (ret < 0)
397 goto out_free_lh;
398
399 /*
400 * Lines have to be requested explicitly for input
401 * or output, else the line will be treated "as is".
402 */
403 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
404 int val = !!handlereq.default_values[i];
405
406 ret = gpiod_direction_output(desc, val);
407 if (ret)
408 goto out_free_lh;
409 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
410 ret = gpiod_direction_input(desc);
411 if (ret)
412 goto out_free_lh;
413 }
414
415 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
416
417 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
418 offset);
419 }
420
421 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
422 if (fd < 0) {
423 ret = fd;
424 goto out_free_lh;
425 }
426
427 file = anon_inode_getfile("gpio-linehandle",
428 &linehandle_fileops,
429 lh,
430 O_RDONLY | O_CLOEXEC);
431 if (IS_ERR(file)) {
432 ret = PTR_ERR(file);
433 goto out_put_unused_fd;
434 }
435
436 handlereq.fd = fd;
437 if (copy_to_user(ip, &handlereq, sizeof(handlereq))) {
438 /*
439 * fput() will trigger the release() callback, so do not go onto
440 * the regular error cleanup path here.
441 */
442 fput(file);
443 put_unused_fd(fd);
444 return -EFAULT;
445 }
446
447 fd_install(fd, file);
448
449 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
450 lh->num_descs);
451
452 return 0;
453
454 out_put_unused_fd:
455 put_unused_fd(fd);
456 out_free_lh:
457 linehandle_free(lh);
458 return ret;
459 }
460 #endif /* CONFIG_GPIO_CDEV_V1 */
461
462 /**
463 * struct line - contains the state of a requested line
464 * @desc: the GPIO descriptor for this line.
465 * @req: the corresponding line request
466 * @irq: the interrupt triggered in response to events on this GPIO
467 * @edflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or
468 * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied
469 * @timestamp_ns: cache for the timestamp storing it between hardirq and
470 * IRQ thread, used to bring the timestamp close to the actual event
471 * @req_seqno: the seqno for the current edge event in the sequence of
472 * events for the corresponding line request. This is drawn from the @req.
473 * @line_seqno: the seqno for the current edge event in the sequence of
474 * events for this line.
475 * @work: the worker that implements software debouncing
476 * @sw_debounced: flag indicating if the software debouncer is active
477 * @level: the current debounced physical level of the line
478 * @hdesc: the Hardware Timestamp Engine (HTE) descriptor
479 * @raw_level: the line level at the time of event
480 * @total_discard_seq: the running counter of the discarded events
481 * @last_seqno: the last sequence number before debounce period expires
482 */
483 struct line {
484 struct gpio_desc *desc;
485 /*
486 * -- edge detector specific fields --
487 */
488 struct linereq *req;
489 unsigned int irq;
490 /*
491 * The flags for the active edge detector configuration.
492 *
493 * edflags is set by linereq_create(), linereq_free(), and
494 * linereq_set_config_unlocked(), which are themselves mutually
495 * exclusive, and is accessed by edge_irq_thread(),
496 * process_hw_ts_thread() and debounce_work_func(),
497 * which can all live with a slightly stale value.
498 */
499 u64 edflags;
500 /*
501 * timestamp_ns and req_seqno are accessed only by
502 * edge_irq_handler() and edge_irq_thread(), which are themselves
503 * mutually exclusive, so no additional protection is necessary.
504 */
505 u64 timestamp_ns;
506 u32 req_seqno;
507 /*
508 * line_seqno is accessed by either edge_irq_thread() or
509 * debounce_work_func(), which are themselves mutually exclusive,
510 * so no additional protection is necessary.
511 */
512 u32 line_seqno;
513 /*
514 * -- debouncer specific fields --
515 */
516 struct delayed_work work;
517 /*
518 * sw_debounce is accessed by linereq_set_config(), which is the
519 * only setter, and linereq_get_values(), which can live with a
520 * slightly stale value.
521 */
522 unsigned int sw_debounced;
523 /*
524 * level is accessed by debounce_work_func(), which is the only
525 * setter, and linereq_get_values() which can live with a slightly
526 * stale value.
527 */
528 unsigned int level;
529 #ifdef CONFIG_HTE
530 struct hte_ts_desc hdesc;
531 /*
532 * HTE provider sets line level at the time of event. The valid
533 * value is 0 or 1 and negative value for an error.
534 */
535 int raw_level;
536 /*
537 * when sw_debounce is set on HTE enabled line, this is running
538 * counter of the discarded events.
539 */
540 u32 total_discard_seq;
541 /*
542 * when sw_debounce is set on HTE enabled line, this variable records
543 * last sequence number before debounce period expires.
544 */
545 u32 last_seqno;
546 #endif /* CONFIG_HTE */
547 };
548
549 /**
550 * struct linereq - contains the state of a userspace line request
551 * @gdev: the GPIO device the line request pertains to
552 * @label: consumer label used to tag GPIO descriptors
553 * @num_lines: the number of lines in the lines array
554 * @wait: wait queue that handles blocking reads of events
555 * @device_unregistered_nb: notifier block for receiving gdev unregister events
556 * @event_buffer_size: the number of elements allocated in @events
557 * @events: KFIFO for the GPIO events
558 * @seqno: the sequence number for edge events generated on all lines in
559 * this line request. Note that this is not used when @num_lines is 1, as
560 * the line_seqno is then the same and is cheaper to calculate.
561 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency
562 * of configuration, particularly multi-step accesses to desc flags.
563 * @lines: the lines held by this line request, with @num_lines elements.
564 */
565 struct linereq {
566 struct gpio_device *gdev;
567 const char *label;
568 u32 num_lines;
569 wait_queue_head_t wait;
570 struct notifier_block device_unregistered_nb;
571 u32 event_buffer_size;
572 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
573 atomic_t seqno;
574 struct mutex config_mutex;
575 struct line lines[];
576 };
577
578 #define GPIO_V2_LINE_BIAS_FLAGS \
579 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \
580 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \
581 GPIO_V2_LINE_FLAG_BIAS_DISABLED)
582
583 #define GPIO_V2_LINE_DIRECTION_FLAGS \
584 (GPIO_V2_LINE_FLAG_INPUT | \
585 GPIO_V2_LINE_FLAG_OUTPUT)
586
587 #define GPIO_V2_LINE_DRIVE_FLAGS \
588 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \
589 GPIO_V2_LINE_FLAG_OPEN_SOURCE)
590
591 #define GPIO_V2_LINE_EDGE_FLAGS \
592 (GPIO_V2_LINE_FLAG_EDGE_RISING | \
593 GPIO_V2_LINE_FLAG_EDGE_FALLING)
594
595 #define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS
596
597 #define GPIO_V2_LINE_VALID_FLAGS \
598 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
599 GPIO_V2_LINE_DIRECTION_FLAGS | \
600 GPIO_V2_LINE_DRIVE_FLAGS | \
601 GPIO_V2_LINE_EDGE_FLAGS | \
602 GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \
603 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
604 GPIO_V2_LINE_BIAS_FLAGS)
605
606 /* subset of flags relevant for edge detector configuration */
607 #define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \
608 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
609 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
610 GPIO_V2_LINE_EDGE_FLAGS)
611
linereq_unregistered_notify(struct notifier_block * nb,unsigned long action,void * data)612 static int linereq_unregistered_notify(struct notifier_block *nb,
613 unsigned long action, void *data)
614 {
615 struct linereq *lr = container_of(nb, struct linereq,
616 device_unregistered_nb);
617
618 wake_up_poll(&lr->wait, EPOLLIN | EPOLLERR);
619
620 return NOTIFY_OK;
621 }
622
linereq_put_event(struct linereq * lr,struct gpio_v2_line_event * le)623 static void linereq_put_event(struct linereq *lr,
624 struct gpio_v2_line_event *le)
625 {
626 bool overflow = false;
627
628 spin_lock(&lr->wait.lock);
629 if (kfifo_is_full(&lr->events)) {
630 overflow = true;
631 kfifo_skip(&lr->events);
632 }
633 kfifo_in(&lr->events, le, 1);
634 spin_unlock(&lr->wait.lock);
635 if (!overflow)
636 wake_up_poll(&lr->wait, EPOLLIN);
637 else
638 pr_debug_ratelimited("event FIFO is full - event dropped\n");
639 }
640
line_event_timestamp(struct line * line)641 static u64 line_event_timestamp(struct line *line)
642 {
643 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags))
644 return ktime_get_real_ns();
645 else if (IS_ENABLED(CONFIG_HTE) &&
646 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))
647 return line->timestamp_ns;
648
649 return ktime_get_ns();
650 }
651
line_event_id(int level)652 static u32 line_event_id(int level)
653 {
654 return level ? GPIO_V2_LINE_EVENT_RISING_EDGE :
655 GPIO_V2_LINE_EVENT_FALLING_EDGE;
656 }
657
658 #ifdef CONFIG_HTE
659
process_hw_ts_thread(void * p)660 static enum hte_return process_hw_ts_thread(void *p)
661 {
662 struct line *line;
663 struct linereq *lr;
664 struct gpio_v2_line_event le;
665 u64 edflags;
666 int level;
667
668 if (!p)
669 return HTE_CB_HANDLED;
670
671 line = p;
672 lr = line->req;
673
674 memset(&le, 0, sizeof(le));
675
676 le.timestamp_ns = line->timestamp_ns;
677 edflags = READ_ONCE(line->edflags);
678
679 switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) {
680 case GPIO_V2_LINE_FLAG_EDGE_BOTH:
681 level = (line->raw_level >= 0) ?
682 line->raw_level :
683 gpiod_get_raw_value_cansleep(line->desc);
684
685 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
686 level = !level;
687
688 le.id = line_event_id(level);
689 break;
690 case GPIO_V2_LINE_FLAG_EDGE_RISING:
691 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
692 break;
693 case GPIO_V2_LINE_FLAG_EDGE_FALLING:
694 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
695 break;
696 default:
697 return HTE_CB_HANDLED;
698 }
699 le.line_seqno = line->line_seqno;
700 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
701 le.offset = gpio_chip_hwgpio(line->desc);
702
703 linereq_put_event(lr, &le);
704
705 return HTE_CB_HANDLED;
706 }
707
process_hw_ts(struct hte_ts_data * ts,void * p)708 static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p)
709 {
710 struct line *line;
711 struct linereq *lr;
712 int diff_seqno = 0;
713
714 if (!ts || !p)
715 return HTE_CB_HANDLED;
716
717 line = p;
718 line->timestamp_ns = ts->tsc;
719 line->raw_level = ts->raw_level;
720 lr = line->req;
721
722 if (READ_ONCE(line->sw_debounced)) {
723 line->total_discard_seq++;
724 line->last_seqno = ts->seq;
725 mod_delayed_work(system_wq, &line->work,
726 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
727 } else {
728 if (unlikely(ts->seq < line->line_seqno))
729 return HTE_CB_HANDLED;
730
731 diff_seqno = ts->seq - line->line_seqno;
732 line->line_seqno = ts->seq;
733 if (lr->num_lines != 1)
734 line->req_seqno = atomic_add_return(diff_seqno,
735 &lr->seqno);
736
737 return HTE_RUN_SECOND_CB;
738 }
739
740 return HTE_CB_HANDLED;
741 }
742
hte_edge_setup(struct line * line,u64 eflags)743 static int hte_edge_setup(struct line *line, u64 eflags)
744 {
745 int ret;
746 unsigned long flags = 0;
747 struct hte_ts_desc *hdesc = &line->hdesc;
748
749 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
750 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
751 HTE_FALLING_EDGE_TS :
752 HTE_RISING_EDGE_TS;
753 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
754 flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
755 HTE_RISING_EDGE_TS :
756 HTE_FALLING_EDGE_TS;
757
758 line->total_discard_seq = 0;
759
760 hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL,
761 line->desc);
762
763 ret = hte_ts_get(NULL, hdesc, 0);
764 if (ret)
765 return ret;
766
767 return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread,
768 line);
769 }
770
771 #else
772
hte_edge_setup(struct line * line,u64 eflags)773 static int hte_edge_setup(struct line *line, u64 eflags)
774 {
775 return 0;
776 }
777 #endif /* CONFIG_HTE */
778
edge_irq_thread(int irq,void * p)779 static irqreturn_t edge_irq_thread(int irq, void *p)
780 {
781 struct line *line = p;
782 struct linereq *lr = line->req;
783 struct gpio_v2_line_event le;
784
785 /* Do not leak kernel stack to userspace */
786 memset(&le, 0, sizeof(le));
787
788 if (line->timestamp_ns) {
789 le.timestamp_ns = line->timestamp_ns;
790 } else {
791 /*
792 * We may be running from a nested threaded interrupt in
793 * which case we didn't get the timestamp from
794 * edge_irq_handler().
795 */
796 le.timestamp_ns = line_event_timestamp(line);
797 if (lr->num_lines != 1)
798 line->req_seqno = atomic_inc_return(&lr->seqno);
799 }
800 line->timestamp_ns = 0;
801
802 switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) {
803 case GPIO_V2_LINE_FLAG_EDGE_BOTH:
804 le.id = line_event_id(gpiod_get_value_cansleep(line->desc));
805 break;
806 case GPIO_V2_LINE_FLAG_EDGE_RISING:
807 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
808 break;
809 case GPIO_V2_LINE_FLAG_EDGE_FALLING:
810 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
811 break;
812 default:
813 return IRQ_NONE;
814 }
815 line->line_seqno++;
816 le.line_seqno = line->line_seqno;
817 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
818 le.offset = gpio_chip_hwgpio(line->desc);
819
820 linereq_put_event(lr, &le);
821
822 return IRQ_HANDLED;
823 }
824
edge_irq_handler(int irq,void * p)825 static irqreturn_t edge_irq_handler(int irq, void *p)
826 {
827 struct line *line = p;
828 struct linereq *lr = line->req;
829
830 /*
831 * Just store the timestamp in hardirq context so we get it as
832 * close in time as possible to the actual event.
833 */
834 line->timestamp_ns = line_event_timestamp(line);
835
836 if (lr->num_lines != 1)
837 line->req_seqno = atomic_inc_return(&lr->seqno);
838
839 return IRQ_WAKE_THREAD;
840 }
841
842 /*
843 * returns the current debounced logical value.
844 */
debounced_value(struct line * line)845 static bool debounced_value(struct line *line)
846 {
847 bool value;
848
849 /*
850 * minor race - debouncer may be stopped here, so edge_detector_stop()
851 * must leave the value unchanged so the following will read the level
852 * from when the debouncer was last running.
853 */
854 value = READ_ONCE(line->level);
855
856 if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
857 value = !value;
858
859 return value;
860 }
861
debounce_irq_handler(int irq,void * p)862 static irqreturn_t debounce_irq_handler(int irq, void *p)
863 {
864 struct line *line = p;
865
866 mod_delayed_work(system_wq, &line->work,
867 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
868
869 return IRQ_HANDLED;
870 }
871
debounce_work_func(struct work_struct * work)872 static void debounce_work_func(struct work_struct *work)
873 {
874 struct gpio_v2_line_event le;
875 struct line *line = container_of(work, struct line, work.work);
876 struct linereq *lr;
877 u64 eflags, edflags = READ_ONCE(line->edflags);
878 int level = -1;
879 #ifdef CONFIG_HTE
880 int diff_seqno;
881
882 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
883 level = line->raw_level;
884 #endif
885 if (level < 0)
886 level = gpiod_get_raw_value_cansleep(line->desc);
887 if (level < 0) {
888 pr_debug_ratelimited("debouncer failed to read line value\n");
889 return;
890 }
891
892 if (READ_ONCE(line->level) == level)
893 return;
894
895 WRITE_ONCE(line->level, level);
896
897 /* -- edge detection -- */
898 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
899 if (!eflags)
900 return;
901
902 /* switch from physical level to logical - if they differ */
903 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
904 level = !level;
905
906 /* ignore edges that are not being monitored */
907 if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) ||
908 ((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level))
909 return;
910
911 /* Do not leak kernel stack to userspace */
912 memset(&le, 0, sizeof(le));
913
914 lr = line->req;
915 le.timestamp_ns = line_event_timestamp(line);
916 le.offset = gpio_chip_hwgpio(line->desc);
917 #ifdef CONFIG_HTE
918 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) {
919 /* discard events except the last one */
920 line->total_discard_seq -= 1;
921 diff_seqno = line->last_seqno - line->total_discard_seq -
922 line->line_seqno;
923 line->line_seqno = line->last_seqno - line->total_discard_seq;
924 le.line_seqno = line->line_seqno;
925 le.seqno = (lr->num_lines == 1) ?
926 le.line_seqno : atomic_add_return(diff_seqno, &lr->seqno);
927 } else
928 #endif /* CONFIG_HTE */
929 {
930 line->line_seqno++;
931 le.line_seqno = line->line_seqno;
932 le.seqno = (lr->num_lines == 1) ?
933 le.line_seqno : atomic_inc_return(&lr->seqno);
934 }
935
936 le.id = line_event_id(level);
937
938 linereq_put_event(lr, &le);
939 }
940
debounce_setup(struct line * line,unsigned int debounce_period_us)941 static int debounce_setup(struct line *line, unsigned int debounce_period_us)
942 {
943 unsigned long irqflags;
944 int ret, level, irq;
945
946 /* try hardware */
947 ret = gpiod_set_debounce(line->desc, debounce_period_us);
948 if (!ret) {
949 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
950 return ret;
951 }
952 if (ret != -ENOTSUPP)
953 return ret;
954
955 if (debounce_period_us) {
956 /* setup software debounce */
957 level = gpiod_get_raw_value_cansleep(line->desc);
958 if (level < 0)
959 return level;
960
961 if (!(IS_ENABLED(CONFIG_HTE) &&
962 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) {
963 irq = gpiod_to_irq(line->desc);
964 if (irq < 0)
965 return -ENXIO;
966
967 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
968 ret = request_irq(irq, debounce_irq_handler, irqflags,
969 line->req->label, line);
970 if (ret)
971 return ret;
972 line->irq = irq;
973 } else {
974 ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH);
975 if (ret)
976 return ret;
977 }
978
979 WRITE_ONCE(line->level, level);
980 WRITE_ONCE(line->sw_debounced, 1);
981 }
982 return 0;
983 }
984
gpio_v2_line_config_debounced(struct gpio_v2_line_config * lc,unsigned int line_idx)985 static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc,
986 unsigned int line_idx)
987 {
988 unsigned int i;
989 u64 mask = BIT_ULL(line_idx);
990
991 for (i = 0; i < lc->num_attrs; i++) {
992 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
993 (lc->attrs[i].mask & mask))
994 return true;
995 }
996 return false;
997 }
998
gpio_v2_line_config_debounce_period(struct gpio_v2_line_config * lc,unsigned int line_idx)999 static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
1000 unsigned int line_idx)
1001 {
1002 unsigned int i;
1003 u64 mask = BIT_ULL(line_idx);
1004
1005 for (i = 0; i < lc->num_attrs; i++) {
1006 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
1007 (lc->attrs[i].mask & mask))
1008 return lc->attrs[i].attr.debounce_period_us;
1009 }
1010 return 0;
1011 }
1012
edge_detector_stop(struct line * line)1013 static void edge_detector_stop(struct line *line)
1014 {
1015 if (line->irq) {
1016 free_irq(line->irq, line);
1017 line->irq = 0;
1018 }
1019
1020 #ifdef CONFIG_HTE
1021 if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
1022 hte_ts_put(&line->hdesc);
1023 #endif
1024
1025 cancel_delayed_work_sync(&line->work);
1026 WRITE_ONCE(line->sw_debounced, 0);
1027 WRITE_ONCE(line->edflags, 0);
1028 if (line->desc)
1029 WRITE_ONCE(line->desc->debounce_period_us, 0);
1030 /* do not change line->level - see comment in debounced_value() */
1031 }
1032
edge_detector_setup(struct line * line,struct gpio_v2_line_config * lc,unsigned int line_idx,u64 edflags)1033 static int edge_detector_setup(struct line *line,
1034 struct gpio_v2_line_config *lc,
1035 unsigned int line_idx, u64 edflags)
1036 {
1037 u32 debounce_period_us;
1038 unsigned long irqflags = 0;
1039 u64 eflags;
1040 int irq, ret;
1041
1042 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
1043 if (eflags && !kfifo_initialized(&line->req->events)) {
1044 ret = kfifo_alloc(&line->req->events,
1045 line->req->event_buffer_size, GFP_KERNEL);
1046 if (ret)
1047 return ret;
1048 }
1049 if (gpio_v2_line_config_debounced(lc, line_idx)) {
1050 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
1051 ret = debounce_setup(line, debounce_period_us);
1052 if (ret)
1053 return ret;
1054 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
1055 }
1056
1057 /* detection disabled or sw debouncer will provide edge detection */
1058 if (!eflags || READ_ONCE(line->sw_debounced))
1059 return 0;
1060
1061 if (IS_ENABLED(CONFIG_HTE) &&
1062 (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1063 return hte_edge_setup(line, edflags);
1064
1065 irq = gpiod_to_irq(line->desc);
1066 if (irq < 0)
1067 return -ENXIO;
1068
1069 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
1070 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
1071 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
1072 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
1073 irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
1074 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
1075 irqflags |= IRQF_ONESHOT;
1076
1077 /* Request a thread to read the events */
1078 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
1079 irqflags, line->req->label, line);
1080 if (ret)
1081 return ret;
1082
1083 line->irq = irq;
1084 return 0;
1085 }
1086
edge_detector_update(struct line * line,struct gpio_v2_line_config * lc,unsigned int line_idx,u64 edflags)1087 static int edge_detector_update(struct line *line,
1088 struct gpio_v2_line_config *lc,
1089 unsigned int line_idx, u64 edflags)
1090 {
1091 u64 active_edflags = READ_ONCE(line->edflags);
1092 unsigned int debounce_period_us =
1093 gpio_v2_line_config_debounce_period(lc, line_idx);
1094
1095 if ((active_edflags == edflags) &&
1096 (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us))
1097 return 0;
1098
1099 /* sw debounced and still will be...*/
1100 if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
1101 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
1102 return 0;
1103 }
1104
1105 /* reconfiguring edge detection or sw debounce being disabled */
1106 if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
1107 (active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) ||
1108 (!debounce_period_us && READ_ONCE(line->sw_debounced)))
1109 edge_detector_stop(line);
1110
1111 return edge_detector_setup(line, lc, line_idx, edflags);
1112 }
1113
gpio_v2_line_config_flags(struct gpio_v2_line_config * lc,unsigned int line_idx)1114 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
1115 unsigned int line_idx)
1116 {
1117 unsigned int i;
1118 u64 mask = BIT_ULL(line_idx);
1119
1120 for (i = 0; i < lc->num_attrs; i++) {
1121 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) &&
1122 (lc->attrs[i].mask & mask))
1123 return lc->attrs[i].attr.flags;
1124 }
1125 return lc->flags;
1126 }
1127
gpio_v2_line_config_output_value(struct gpio_v2_line_config * lc,unsigned int line_idx)1128 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc,
1129 unsigned int line_idx)
1130 {
1131 unsigned int i;
1132 u64 mask = BIT_ULL(line_idx);
1133
1134 for (i = 0; i < lc->num_attrs; i++) {
1135 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) &&
1136 (lc->attrs[i].mask & mask))
1137 return !!(lc->attrs[i].attr.values & mask);
1138 }
1139 return 0;
1140 }
1141
gpio_v2_line_flags_validate(u64 flags)1142 static int gpio_v2_line_flags_validate(u64 flags)
1143 {
1144 /* Return an error if an unknown flag is set */
1145 if (flags & ~GPIO_V2_LINE_VALID_FLAGS)
1146 return -EINVAL;
1147
1148 if (!IS_ENABLED(CONFIG_HTE) &&
1149 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1150 return -EOPNOTSUPP;
1151
1152 /*
1153 * Do not allow both INPUT and OUTPUT flags to be set as they are
1154 * contradictory.
1155 */
1156 if ((flags & GPIO_V2_LINE_FLAG_INPUT) &&
1157 (flags & GPIO_V2_LINE_FLAG_OUTPUT))
1158 return -EINVAL;
1159
1160 /* Only allow one event clock source */
1161 if (IS_ENABLED(CONFIG_HTE) &&
1162 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME) &&
1163 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1164 return -EINVAL;
1165
1166 /* Edge detection requires explicit input. */
1167 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) &&
1168 !(flags & GPIO_V2_LINE_FLAG_INPUT))
1169 return -EINVAL;
1170
1171 /*
1172 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single
1173 * request. If the hardware actually supports enabling both at the
1174 * same time the electrical result would be disastrous.
1175 */
1176 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) &&
1177 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE))
1178 return -EINVAL;
1179
1180 /* Drive requires explicit output direction. */
1181 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) &&
1182 !(flags & GPIO_V2_LINE_FLAG_OUTPUT))
1183 return -EINVAL;
1184
1185 /* Bias requires explicit direction. */
1186 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) &&
1187 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
1188 return -EINVAL;
1189
1190 /* Only one bias flag can be set. */
1191 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) &&
1192 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN |
1193 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) ||
1194 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) &&
1195 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)))
1196 return -EINVAL;
1197
1198 return 0;
1199 }
1200
gpio_v2_line_config_validate(struct gpio_v2_line_config * lc,unsigned int num_lines)1201 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
1202 unsigned int num_lines)
1203 {
1204 unsigned int i;
1205 u64 flags;
1206 int ret;
1207
1208 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX)
1209 return -EINVAL;
1210
1211 if (memchr_inv(lc->padding, 0, sizeof(lc->padding)))
1212 return -EINVAL;
1213
1214 for (i = 0; i < num_lines; i++) {
1215 flags = gpio_v2_line_config_flags(lc, i);
1216 ret = gpio_v2_line_flags_validate(flags);
1217 if (ret)
1218 return ret;
1219
1220 /* debounce requires explicit input */
1221 if (gpio_v2_line_config_debounced(lc, i) &&
1222 !(flags & GPIO_V2_LINE_FLAG_INPUT))
1223 return -EINVAL;
1224 }
1225 return 0;
1226 }
1227
gpio_v2_line_config_flags_to_desc_flags(u64 flags,unsigned long * flagsp)1228 static void gpio_v2_line_config_flags_to_desc_flags(u64 flags,
1229 unsigned long *flagsp)
1230 {
1231 assign_bit(FLAG_ACTIVE_LOW, flagsp,
1232 flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW);
1233
1234 if (flags & GPIO_V2_LINE_FLAG_OUTPUT)
1235 set_bit(FLAG_IS_OUT, flagsp);
1236 else if (flags & GPIO_V2_LINE_FLAG_INPUT)
1237 clear_bit(FLAG_IS_OUT, flagsp);
1238
1239 assign_bit(FLAG_EDGE_RISING, flagsp,
1240 flags & GPIO_V2_LINE_FLAG_EDGE_RISING);
1241 assign_bit(FLAG_EDGE_FALLING, flagsp,
1242 flags & GPIO_V2_LINE_FLAG_EDGE_FALLING);
1243
1244 assign_bit(FLAG_OPEN_DRAIN, flagsp,
1245 flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN);
1246 assign_bit(FLAG_OPEN_SOURCE, flagsp,
1247 flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE);
1248
1249 assign_bit(FLAG_PULL_UP, flagsp,
1250 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP);
1251 assign_bit(FLAG_PULL_DOWN, flagsp,
1252 flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN);
1253 assign_bit(FLAG_BIAS_DISABLE, flagsp,
1254 flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED);
1255
1256 assign_bit(FLAG_EVENT_CLOCK_REALTIME, flagsp,
1257 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME);
1258 assign_bit(FLAG_EVENT_CLOCK_HTE, flagsp,
1259 flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE);
1260 }
1261
linereq_get_values(struct linereq * lr,void __user * ip)1262 static long linereq_get_values(struct linereq *lr, void __user *ip)
1263 {
1264 struct gpio_v2_line_values lv;
1265 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1266 struct gpio_desc **descs;
1267 unsigned int i, didx, num_get;
1268 bool val;
1269 int ret;
1270
1271 /* NOTE: It's ok to read values of output lines. */
1272 if (copy_from_user(&lv, ip, sizeof(lv)))
1273 return -EFAULT;
1274
1275 for (num_get = 0, i = 0; i < lr->num_lines; i++) {
1276 if (lv.mask & BIT_ULL(i)) {
1277 num_get++;
1278 descs = &lr->lines[i].desc;
1279 }
1280 }
1281
1282 if (num_get == 0)
1283 return -EINVAL;
1284
1285 if (num_get != 1) {
1286 descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL);
1287 if (!descs)
1288 return -ENOMEM;
1289 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1290 if (lv.mask & BIT_ULL(i)) {
1291 descs[didx] = lr->lines[i].desc;
1292 didx++;
1293 }
1294 }
1295 }
1296 ret = gpiod_get_array_value_complex(false, true, num_get,
1297 descs, NULL, vals);
1298
1299 if (num_get != 1)
1300 kfree(descs);
1301 if (ret)
1302 return ret;
1303
1304 lv.bits = 0;
1305 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1306 if (lv.mask & BIT_ULL(i)) {
1307 if (lr->lines[i].sw_debounced)
1308 val = debounced_value(&lr->lines[i]);
1309 else
1310 val = test_bit(didx, vals);
1311 if (val)
1312 lv.bits |= BIT_ULL(i);
1313 didx++;
1314 }
1315 }
1316
1317 if (copy_to_user(ip, &lv, sizeof(lv)))
1318 return -EFAULT;
1319
1320 return 0;
1321 }
1322
linereq_set_values_unlocked(struct linereq * lr,struct gpio_v2_line_values * lv)1323 static long linereq_set_values_unlocked(struct linereq *lr,
1324 struct gpio_v2_line_values *lv)
1325 {
1326 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1327 struct gpio_desc **descs;
1328 unsigned int i, didx, num_set;
1329 int ret;
1330
1331 bitmap_zero(vals, GPIO_V2_LINES_MAX);
1332 for (num_set = 0, i = 0; i < lr->num_lines; i++) {
1333 if (lv->mask & BIT_ULL(i)) {
1334 if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
1335 return -EPERM;
1336 if (lv->bits & BIT_ULL(i))
1337 __set_bit(num_set, vals);
1338 num_set++;
1339 descs = &lr->lines[i].desc;
1340 }
1341 }
1342 if (num_set == 0)
1343 return -EINVAL;
1344
1345 if (num_set != 1) {
1346 /* build compacted desc array and values */
1347 descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);
1348 if (!descs)
1349 return -ENOMEM;
1350 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1351 if (lv->mask & BIT_ULL(i)) {
1352 descs[didx] = lr->lines[i].desc;
1353 didx++;
1354 }
1355 }
1356 }
1357 ret = gpiod_set_array_value_complex(false, true, num_set,
1358 descs, NULL, vals);
1359
1360 if (num_set != 1)
1361 kfree(descs);
1362 return ret;
1363 }
1364
linereq_set_values(struct linereq * lr,void __user * ip)1365 static long linereq_set_values(struct linereq *lr, void __user *ip)
1366 {
1367 struct gpio_v2_line_values lv;
1368 int ret;
1369
1370 if (copy_from_user(&lv, ip, sizeof(lv)))
1371 return -EFAULT;
1372
1373 mutex_lock(&lr->config_mutex);
1374
1375 ret = linereq_set_values_unlocked(lr, &lv);
1376
1377 mutex_unlock(&lr->config_mutex);
1378
1379 return ret;
1380 }
1381
linereq_set_config_unlocked(struct linereq * lr,struct gpio_v2_line_config * lc)1382 static long linereq_set_config_unlocked(struct linereq *lr,
1383 struct gpio_v2_line_config *lc)
1384 {
1385 struct gpio_desc *desc;
1386 struct line *line;
1387 unsigned int i;
1388 u64 flags, edflags;
1389 int ret;
1390
1391 for (i = 0; i < lr->num_lines; i++) {
1392 line = &lr->lines[i];
1393 desc = lr->lines[i].desc;
1394 flags = gpio_v2_line_config_flags(lc, i);
1395 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1396 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
1397 /*
1398 * Lines have to be requested explicitly for input
1399 * or output, else the line will be treated "as is".
1400 */
1401 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1402 int val = gpio_v2_line_config_output_value(lc, i);
1403
1404 edge_detector_stop(line);
1405 ret = gpiod_direction_output(desc, val);
1406 if (ret)
1407 return ret;
1408 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1409 ret = gpiod_direction_input(desc);
1410 if (ret)
1411 return ret;
1412
1413 ret = edge_detector_update(line, lc, i, edflags);
1414 if (ret)
1415 return ret;
1416 }
1417
1418 WRITE_ONCE(line->edflags, edflags);
1419
1420 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
1421 }
1422 return 0;
1423 }
1424
linereq_set_config(struct linereq * lr,void __user * ip)1425 static long linereq_set_config(struct linereq *lr, void __user *ip)
1426 {
1427 struct gpio_v2_line_config lc;
1428 int ret;
1429
1430 if (copy_from_user(&lc, ip, sizeof(lc)))
1431 return -EFAULT;
1432
1433 ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
1434 if (ret)
1435 return ret;
1436
1437 mutex_lock(&lr->config_mutex);
1438
1439 ret = linereq_set_config_unlocked(lr, &lc);
1440
1441 mutex_unlock(&lr->config_mutex);
1442
1443 return ret;
1444 }
1445
linereq_ioctl_unlocked(struct file * file,unsigned int cmd,unsigned long arg)1446 static long linereq_ioctl_unlocked(struct file *file, unsigned int cmd,
1447 unsigned long arg)
1448 {
1449 struct linereq *lr = file->private_data;
1450 void __user *ip = (void __user *)arg;
1451
1452 if (!lr->gdev->chip)
1453 return -ENODEV;
1454
1455 switch (cmd) {
1456 case GPIO_V2_LINE_GET_VALUES_IOCTL:
1457 return linereq_get_values(lr, ip);
1458 case GPIO_V2_LINE_SET_VALUES_IOCTL:
1459 return linereq_set_values(lr, ip);
1460 case GPIO_V2_LINE_SET_CONFIG_IOCTL:
1461 return linereq_set_config(lr, ip);
1462 default:
1463 return -EINVAL;
1464 }
1465 }
1466
linereq_ioctl(struct file * file,unsigned int cmd,unsigned long arg)1467 static long linereq_ioctl(struct file *file, unsigned int cmd,
1468 unsigned long arg)
1469 {
1470 struct linereq *lr = file->private_data;
1471
1472 return call_ioctl_locked(file, cmd, arg, lr->gdev,
1473 linereq_ioctl_unlocked);
1474 }
1475
1476 #ifdef CONFIG_COMPAT
linereq_ioctl_compat(struct file * file,unsigned int cmd,unsigned long arg)1477 static long linereq_ioctl_compat(struct file *file, unsigned int cmd,
1478 unsigned long arg)
1479 {
1480 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1481 }
1482 #endif
1483
linereq_poll_unlocked(struct file * file,struct poll_table_struct * wait)1484 static __poll_t linereq_poll_unlocked(struct file *file,
1485 struct poll_table_struct *wait)
1486 {
1487 struct linereq *lr = file->private_data;
1488 __poll_t events = 0;
1489
1490 if (!lr->gdev->chip)
1491 return EPOLLHUP | EPOLLERR;
1492
1493 poll_wait(file, &lr->wait, wait);
1494
1495 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events,
1496 &lr->wait.lock))
1497 events = EPOLLIN | EPOLLRDNORM;
1498
1499 return events;
1500 }
1501
linereq_poll(struct file * file,struct poll_table_struct * wait)1502 static __poll_t linereq_poll(struct file *file,
1503 struct poll_table_struct *wait)
1504 {
1505 struct linereq *lr = file->private_data;
1506
1507 return call_poll_locked(file, wait, lr->gdev, linereq_poll_unlocked);
1508 }
1509
linereq_read_unlocked(struct file * file,char __user * buf,size_t count,loff_t * f_ps)1510 static ssize_t linereq_read_unlocked(struct file *file, char __user *buf,
1511 size_t count, loff_t *f_ps)
1512 {
1513 struct linereq *lr = file->private_data;
1514 struct gpio_v2_line_event le;
1515 ssize_t bytes_read = 0;
1516 int ret;
1517
1518 if (!lr->gdev->chip)
1519 return -ENODEV;
1520
1521 if (count < sizeof(le))
1522 return -EINVAL;
1523
1524 do {
1525 spin_lock(&lr->wait.lock);
1526 if (kfifo_is_empty(&lr->events)) {
1527 if (bytes_read) {
1528 spin_unlock(&lr->wait.lock);
1529 return bytes_read;
1530 }
1531
1532 if (file->f_flags & O_NONBLOCK) {
1533 spin_unlock(&lr->wait.lock);
1534 return -EAGAIN;
1535 }
1536
1537 ret = wait_event_interruptible_locked(lr->wait,
1538 !kfifo_is_empty(&lr->events));
1539 if (ret) {
1540 spin_unlock(&lr->wait.lock);
1541 return ret;
1542 }
1543 }
1544
1545 ret = kfifo_out(&lr->events, &le, 1);
1546 spin_unlock(&lr->wait.lock);
1547 if (ret != 1) {
1548 /*
1549 * This should never happen - we were holding the
1550 * lock from the moment we learned the fifo is no
1551 * longer empty until now.
1552 */
1553 ret = -EIO;
1554 break;
1555 }
1556
1557 if (copy_to_user(buf + bytes_read, &le, sizeof(le)))
1558 return -EFAULT;
1559 bytes_read += sizeof(le);
1560 } while (count >= bytes_read + sizeof(le));
1561
1562 return bytes_read;
1563 }
1564
linereq_read(struct file * file,char __user * buf,size_t count,loff_t * f_ps)1565 static ssize_t linereq_read(struct file *file, char __user *buf,
1566 size_t count, loff_t *f_ps)
1567 {
1568 struct linereq *lr = file->private_data;
1569
1570 return call_read_locked(file, buf, count, f_ps, lr->gdev,
1571 linereq_read_unlocked);
1572 }
1573
linereq_free(struct linereq * lr)1574 static void linereq_free(struct linereq *lr)
1575 {
1576 unsigned int i;
1577
1578 if (lr->device_unregistered_nb.notifier_call)
1579 blocking_notifier_chain_unregister(&lr->gdev->device_notifier,
1580 &lr->device_unregistered_nb);
1581
1582 for (i = 0; i < lr->num_lines; i++) {
1583 if (lr->lines[i].desc) {
1584 edge_detector_stop(&lr->lines[i]);
1585 gpiod_free(lr->lines[i].desc);
1586 }
1587 }
1588 kfifo_free(&lr->events);
1589 kfree(lr->label);
1590 gpio_device_put(lr->gdev);
1591 kfree(lr);
1592 }
1593
linereq_release(struct inode * inode,struct file * file)1594 static int linereq_release(struct inode *inode, struct file *file)
1595 {
1596 struct linereq *lr = file->private_data;
1597
1598 linereq_free(lr);
1599 return 0;
1600 }
1601
1602 #ifdef CONFIG_PROC_FS
linereq_show_fdinfo(struct seq_file * out,struct file * file)1603 static void linereq_show_fdinfo(struct seq_file *out, struct file *file)
1604 {
1605 struct linereq *lr = file->private_data;
1606 struct device *dev = &lr->gdev->dev;
1607 u16 i;
1608
1609 seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev));
1610
1611 for (i = 0; i < lr->num_lines; i++)
1612 seq_printf(out, "gpio-line:\t%d\n",
1613 gpio_chip_hwgpio(lr->lines[i].desc));
1614 }
1615 #endif
1616
1617 static const struct file_operations line_fileops = {
1618 .release = linereq_release,
1619 .read = linereq_read,
1620 .poll = linereq_poll,
1621 .owner = THIS_MODULE,
1622 .llseek = noop_llseek,
1623 .unlocked_ioctl = linereq_ioctl,
1624 #ifdef CONFIG_COMPAT
1625 .compat_ioctl = linereq_ioctl_compat,
1626 #endif
1627 #ifdef CONFIG_PROC_FS
1628 .show_fdinfo = linereq_show_fdinfo,
1629 #endif
1630 };
1631
linereq_create(struct gpio_device * gdev,void __user * ip)1632 static int linereq_create(struct gpio_device *gdev, void __user *ip)
1633 {
1634 struct gpio_v2_line_request ulr;
1635 struct gpio_v2_line_config *lc;
1636 struct linereq *lr;
1637 struct file *file;
1638 u64 flags, edflags;
1639 unsigned int i;
1640 int fd, ret;
1641
1642 if (copy_from_user(&ulr, ip, sizeof(ulr)))
1643 return -EFAULT;
1644
1645 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
1646 return -EINVAL;
1647
1648 if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding)))
1649 return -EINVAL;
1650
1651 lc = &ulr.config;
1652 ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
1653 if (ret)
1654 return ret;
1655
1656 lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
1657 if (!lr)
1658 return -ENOMEM;
1659
1660 lr->gdev = gpio_device_get(gdev);
1661
1662 for (i = 0; i < ulr.num_lines; i++) {
1663 lr->lines[i].req = lr;
1664 WRITE_ONCE(lr->lines[i].sw_debounced, 0);
1665 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
1666 }
1667
1668 if (ulr.consumer[0] != '\0') {
1669 /* label is only initialized if consumer is set */
1670 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
1671 GFP_KERNEL);
1672 if (!lr->label) {
1673 ret = -ENOMEM;
1674 goto out_free_linereq;
1675 }
1676 }
1677
1678 mutex_init(&lr->config_mutex);
1679 init_waitqueue_head(&lr->wait);
1680 lr->event_buffer_size = ulr.event_buffer_size;
1681 if (lr->event_buffer_size == 0)
1682 lr->event_buffer_size = ulr.num_lines * 16;
1683 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16)
1684 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;
1685
1686 atomic_set(&lr->seqno, 0);
1687 lr->num_lines = ulr.num_lines;
1688
1689 /* Request each GPIO */
1690 for (i = 0; i < ulr.num_lines; i++) {
1691 u32 offset = ulr.offsets[i];
1692 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
1693
1694 if (IS_ERR(desc)) {
1695 ret = PTR_ERR(desc);
1696 goto out_free_linereq;
1697 }
1698
1699 ret = gpiod_request_user(desc, lr->label);
1700 if (ret)
1701 goto out_free_linereq;
1702
1703 lr->lines[i].desc = desc;
1704 flags = gpio_v2_line_config_flags(lc, i);
1705 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1706
1707 ret = gpiod_set_transitory(desc, false);
1708 if (ret < 0)
1709 goto out_free_linereq;
1710
1711 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
1712 /*
1713 * Lines have to be requested explicitly for input
1714 * or output, else the line will be treated "as is".
1715 */
1716 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1717 int val = gpio_v2_line_config_output_value(lc, i);
1718
1719 ret = gpiod_direction_output(desc, val);
1720 if (ret)
1721 goto out_free_linereq;
1722 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1723 ret = gpiod_direction_input(desc);
1724 if (ret)
1725 goto out_free_linereq;
1726
1727 ret = edge_detector_setup(&lr->lines[i], lc, i,
1728 edflags);
1729 if (ret)
1730 goto out_free_linereq;
1731 }
1732
1733 lr->lines[i].edflags = edflags;
1734
1735 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
1736
1737 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
1738 offset);
1739 }
1740
1741 lr->device_unregistered_nb.notifier_call = linereq_unregistered_notify;
1742 ret = blocking_notifier_chain_register(&gdev->device_notifier,
1743 &lr->device_unregistered_nb);
1744 if (ret)
1745 goto out_free_linereq;
1746
1747 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
1748 if (fd < 0) {
1749 ret = fd;
1750 goto out_free_linereq;
1751 }
1752
1753 file = anon_inode_getfile("gpio-line", &line_fileops, lr,
1754 O_RDONLY | O_CLOEXEC);
1755 if (IS_ERR(file)) {
1756 ret = PTR_ERR(file);
1757 goto out_put_unused_fd;
1758 }
1759
1760 ulr.fd = fd;
1761 if (copy_to_user(ip, &ulr, sizeof(ulr))) {
1762 /*
1763 * fput() will trigger the release() callback, so do not go onto
1764 * the regular error cleanup path here.
1765 */
1766 fput(file);
1767 put_unused_fd(fd);
1768 return -EFAULT;
1769 }
1770
1771 fd_install(fd, file);
1772
1773 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
1774 lr->num_lines);
1775
1776 return 0;
1777
1778 out_put_unused_fd:
1779 put_unused_fd(fd);
1780 out_free_linereq:
1781 linereq_free(lr);
1782 return ret;
1783 }
1784
1785 #ifdef CONFIG_GPIO_CDEV_V1
1786
1787 /*
1788 * GPIO line event management
1789 */
1790
1791 /**
1792 * struct lineevent_state - contains the state of a userspace event
1793 * @gdev: the GPIO device the event pertains to
1794 * @label: consumer label used to tag descriptors
1795 * @desc: the GPIO descriptor held by this event
1796 * @eflags: the event flags this line was requested with
1797 * @irq: the interrupt that trigger in response to events on this GPIO
1798 * @wait: wait queue that handles blocking reads of events
1799 * @device_unregistered_nb: notifier block for receiving gdev unregister events
1800 * @events: KFIFO for the GPIO events
1801 * @timestamp: cache for the timestamp storing it between hardirq
1802 * and IRQ thread, used to bring the timestamp close to the actual
1803 * event
1804 */
1805 struct lineevent_state {
1806 struct gpio_device *gdev;
1807 const char *label;
1808 struct gpio_desc *desc;
1809 u32 eflags;
1810 int irq;
1811 wait_queue_head_t wait;
1812 struct notifier_block device_unregistered_nb;
1813 DECLARE_KFIFO(events, struct gpioevent_data, 16);
1814 u64 timestamp;
1815 };
1816
1817 #define GPIOEVENT_REQUEST_VALID_FLAGS \
1818 (GPIOEVENT_REQUEST_RISING_EDGE | \
1819 GPIOEVENT_REQUEST_FALLING_EDGE)
1820
lineevent_poll_unlocked(struct file * file,struct poll_table_struct * wait)1821 static __poll_t lineevent_poll_unlocked(struct file *file,
1822 struct poll_table_struct *wait)
1823 {
1824 struct lineevent_state *le = file->private_data;
1825 __poll_t events = 0;
1826
1827 if (!le->gdev->chip)
1828 return EPOLLHUP | EPOLLERR;
1829
1830 poll_wait(file, &le->wait, wait);
1831
1832 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
1833 events = EPOLLIN | EPOLLRDNORM;
1834
1835 return events;
1836 }
1837
lineevent_poll(struct file * file,struct poll_table_struct * wait)1838 static __poll_t lineevent_poll(struct file *file,
1839 struct poll_table_struct *wait)
1840 {
1841 struct lineevent_state *le = file->private_data;
1842
1843 return call_poll_locked(file, wait, le->gdev, lineevent_poll_unlocked);
1844 }
1845
lineevent_unregistered_notify(struct notifier_block * nb,unsigned long action,void * data)1846 static int lineevent_unregistered_notify(struct notifier_block *nb,
1847 unsigned long action, void *data)
1848 {
1849 struct lineevent_state *le = container_of(nb, struct lineevent_state,
1850 device_unregistered_nb);
1851
1852 wake_up_poll(&le->wait, EPOLLIN | EPOLLERR);
1853
1854 return NOTIFY_OK;
1855 }
1856
1857 struct compat_gpioeevent_data {
1858 compat_u64 timestamp;
1859 u32 id;
1860 };
1861
lineevent_read_unlocked(struct file * file,char __user * buf,size_t count,loff_t * f_ps)1862 static ssize_t lineevent_read_unlocked(struct file *file, char __user *buf,
1863 size_t count, loff_t *f_ps)
1864 {
1865 struct lineevent_state *le = file->private_data;
1866 struct gpioevent_data ge;
1867 ssize_t bytes_read = 0;
1868 ssize_t ge_size;
1869 int ret;
1870
1871 if (!le->gdev->chip)
1872 return -ENODEV;
1873
1874 /*
1875 * When compatible system call is being used the struct gpioevent_data,
1876 * in case of at least ia32, has different size due to the alignment
1877 * differences. Because we have first member 64 bits followed by one of
1878 * 32 bits there is no gap between them. The only difference is the
1879 * padding at the end of the data structure. Hence, we calculate the
1880 * actual sizeof() and pass this as an argument to copy_to_user() to
1881 * drop unneeded bytes from the output.
1882 */
1883 if (compat_need_64bit_alignment_fixup())
1884 ge_size = sizeof(struct compat_gpioeevent_data);
1885 else
1886 ge_size = sizeof(struct gpioevent_data);
1887 if (count < ge_size)
1888 return -EINVAL;
1889
1890 do {
1891 spin_lock(&le->wait.lock);
1892 if (kfifo_is_empty(&le->events)) {
1893 if (bytes_read) {
1894 spin_unlock(&le->wait.lock);
1895 return bytes_read;
1896 }
1897
1898 if (file->f_flags & O_NONBLOCK) {
1899 spin_unlock(&le->wait.lock);
1900 return -EAGAIN;
1901 }
1902
1903 ret = wait_event_interruptible_locked(le->wait,
1904 !kfifo_is_empty(&le->events));
1905 if (ret) {
1906 spin_unlock(&le->wait.lock);
1907 return ret;
1908 }
1909 }
1910
1911 ret = kfifo_out(&le->events, &ge, 1);
1912 spin_unlock(&le->wait.lock);
1913 if (ret != 1) {
1914 /*
1915 * This should never happen - we were holding the lock
1916 * from the moment we learned the fifo is no longer
1917 * empty until now.
1918 */
1919 ret = -EIO;
1920 break;
1921 }
1922
1923 if (copy_to_user(buf + bytes_read, &ge, ge_size))
1924 return -EFAULT;
1925 bytes_read += ge_size;
1926 } while (count >= bytes_read + ge_size);
1927
1928 return bytes_read;
1929 }
1930
lineevent_read(struct file * file,char __user * buf,size_t count,loff_t * f_ps)1931 static ssize_t lineevent_read(struct file *file, char __user *buf,
1932 size_t count, loff_t *f_ps)
1933 {
1934 struct lineevent_state *le = file->private_data;
1935
1936 return call_read_locked(file, buf, count, f_ps, le->gdev,
1937 lineevent_read_unlocked);
1938 }
1939
lineevent_free(struct lineevent_state * le)1940 static void lineevent_free(struct lineevent_state *le)
1941 {
1942 if (le->device_unregistered_nb.notifier_call)
1943 blocking_notifier_chain_unregister(&le->gdev->device_notifier,
1944 &le->device_unregistered_nb);
1945 if (le->irq)
1946 free_irq(le->irq, le);
1947 if (le->desc)
1948 gpiod_free(le->desc);
1949 kfree(le->label);
1950 gpio_device_put(le->gdev);
1951 kfree(le);
1952 }
1953
lineevent_release(struct inode * inode,struct file * file)1954 static int lineevent_release(struct inode *inode, struct file *file)
1955 {
1956 lineevent_free(file->private_data);
1957 return 0;
1958 }
1959
lineevent_ioctl_unlocked(struct file * file,unsigned int cmd,unsigned long arg)1960 static long lineevent_ioctl_unlocked(struct file *file, unsigned int cmd,
1961 unsigned long arg)
1962 {
1963 struct lineevent_state *le = file->private_data;
1964 void __user *ip = (void __user *)arg;
1965 struct gpiohandle_data ghd;
1966
1967 if (!le->gdev->chip)
1968 return -ENODEV;
1969
1970 /*
1971 * We can get the value for an event line but not set it,
1972 * because it is input by definition.
1973 */
1974 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
1975 int val;
1976
1977 memset(&ghd, 0, sizeof(ghd));
1978
1979 val = gpiod_get_value_cansleep(le->desc);
1980 if (val < 0)
1981 return val;
1982 ghd.values[0] = val;
1983
1984 if (copy_to_user(ip, &ghd, sizeof(ghd)))
1985 return -EFAULT;
1986
1987 return 0;
1988 }
1989 return -EINVAL;
1990 }
1991
lineevent_ioctl(struct file * file,unsigned int cmd,unsigned long arg)1992 static long lineevent_ioctl(struct file *file, unsigned int cmd,
1993 unsigned long arg)
1994 {
1995 struct lineevent_state *le = file->private_data;
1996
1997 return call_ioctl_locked(file, cmd, arg, le->gdev,
1998 lineevent_ioctl_unlocked);
1999 }
2000
2001 #ifdef CONFIG_COMPAT
lineevent_ioctl_compat(struct file * file,unsigned int cmd,unsigned long arg)2002 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd,
2003 unsigned long arg)
2004 {
2005 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2006 }
2007 #endif
2008
2009 static const struct file_operations lineevent_fileops = {
2010 .release = lineevent_release,
2011 .read = lineevent_read,
2012 .poll = lineevent_poll,
2013 .owner = THIS_MODULE,
2014 .llseek = noop_llseek,
2015 .unlocked_ioctl = lineevent_ioctl,
2016 #ifdef CONFIG_COMPAT
2017 .compat_ioctl = lineevent_ioctl_compat,
2018 #endif
2019 };
2020
lineevent_irq_thread(int irq,void * p)2021 static irqreturn_t lineevent_irq_thread(int irq, void *p)
2022 {
2023 struct lineevent_state *le = p;
2024 struct gpioevent_data ge;
2025 int ret;
2026
2027 /* Do not leak kernel stack to userspace */
2028 memset(&ge, 0, sizeof(ge));
2029
2030 /*
2031 * We may be running from a nested threaded interrupt in which case
2032 * we didn't get the timestamp from lineevent_irq_handler().
2033 */
2034 if (!le->timestamp)
2035 ge.timestamp = ktime_get_ns();
2036 else
2037 ge.timestamp = le->timestamp;
2038
2039 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
2040 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
2041 int level = gpiod_get_value_cansleep(le->desc);
2042
2043 if (level)
2044 /* Emit low-to-high event */
2045 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
2046 else
2047 /* Emit high-to-low event */
2048 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
2049 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
2050 /* Emit low-to-high event */
2051 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
2052 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
2053 /* Emit high-to-low event */
2054 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
2055 } else {
2056 return IRQ_NONE;
2057 }
2058
2059 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
2060 1, &le->wait.lock);
2061 if (ret)
2062 wake_up_poll(&le->wait, EPOLLIN);
2063 else
2064 pr_debug_ratelimited("event FIFO is full - event dropped\n");
2065
2066 return IRQ_HANDLED;
2067 }
2068
lineevent_irq_handler(int irq,void * p)2069 static irqreturn_t lineevent_irq_handler(int irq, void *p)
2070 {
2071 struct lineevent_state *le = p;
2072
2073 /*
2074 * Just store the timestamp in hardirq context so we get it as
2075 * close in time as possible to the actual event.
2076 */
2077 le->timestamp = ktime_get_ns();
2078
2079 return IRQ_WAKE_THREAD;
2080 }
2081
lineevent_create(struct gpio_device * gdev,void __user * ip)2082 static int lineevent_create(struct gpio_device *gdev, void __user *ip)
2083 {
2084 struct gpioevent_request eventreq;
2085 struct lineevent_state *le;
2086 struct gpio_desc *desc;
2087 struct file *file;
2088 u32 offset;
2089 u32 lflags;
2090 u32 eflags;
2091 int fd;
2092 int ret;
2093 int irq, irqflags = 0;
2094
2095 if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
2096 return -EFAULT;
2097
2098 offset = eventreq.lineoffset;
2099 lflags = eventreq.handleflags;
2100 eflags = eventreq.eventflags;
2101
2102 desc = gpiochip_get_desc(gdev->chip, offset);
2103 if (IS_ERR(desc))
2104 return PTR_ERR(desc);
2105
2106 /* Return an error if a unknown flag is set */
2107 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
2108 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
2109 return -EINVAL;
2110
2111 /* This is just wrong: we don't look for events on output lines */
2112 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
2113 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
2114 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
2115 return -EINVAL;
2116
2117 /* Only one bias flag can be set. */
2118 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
2119 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
2120 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
2121 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
2122 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
2123 return -EINVAL;
2124
2125 le = kzalloc(sizeof(*le), GFP_KERNEL);
2126 if (!le)
2127 return -ENOMEM;
2128 le->gdev = gpio_device_get(gdev);
2129
2130 if (eventreq.consumer_label[0] != '\0') {
2131 /* label is only initialized if consumer_label is set */
2132 le->label = kstrndup(eventreq.consumer_label,
2133 sizeof(eventreq.consumer_label) - 1,
2134 GFP_KERNEL);
2135 if (!le->label) {
2136 ret = -ENOMEM;
2137 goto out_free_le;
2138 }
2139 }
2140
2141 ret = gpiod_request_user(desc, le->label);
2142 if (ret)
2143 goto out_free_le;
2144 le->desc = desc;
2145 le->eflags = eflags;
2146
2147 linehandle_flags_to_desc_flags(lflags, &desc->flags);
2148
2149 ret = gpiod_direction_input(desc);
2150 if (ret)
2151 goto out_free_le;
2152
2153 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
2154
2155 irq = gpiod_to_irq(desc);
2156 if (irq <= 0) {
2157 ret = -ENODEV;
2158 goto out_free_le;
2159 }
2160
2161 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
2162 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
2163 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
2164 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
2165 irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
2166 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
2167 irqflags |= IRQF_ONESHOT;
2168
2169 INIT_KFIFO(le->events);
2170 init_waitqueue_head(&le->wait);
2171
2172 le->device_unregistered_nb.notifier_call = lineevent_unregistered_notify;
2173 ret = blocking_notifier_chain_register(&gdev->device_notifier,
2174 &le->device_unregistered_nb);
2175 if (ret)
2176 goto out_free_le;
2177
2178 /* Request a thread to read the events */
2179 ret = request_threaded_irq(irq,
2180 lineevent_irq_handler,
2181 lineevent_irq_thread,
2182 irqflags,
2183 le->label,
2184 le);
2185 if (ret)
2186 goto out_free_le;
2187
2188 le->irq = irq;
2189
2190 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
2191 if (fd < 0) {
2192 ret = fd;
2193 goto out_free_le;
2194 }
2195
2196 file = anon_inode_getfile("gpio-event",
2197 &lineevent_fileops,
2198 le,
2199 O_RDONLY | O_CLOEXEC);
2200 if (IS_ERR(file)) {
2201 ret = PTR_ERR(file);
2202 goto out_put_unused_fd;
2203 }
2204
2205 eventreq.fd = fd;
2206 if (copy_to_user(ip, &eventreq, sizeof(eventreq))) {
2207 /*
2208 * fput() will trigger the release() callback, so do not go onto
2209 * the regular error cleanup path here.
2210 */
2211 fput(file);
2212 put_unused_fd(fd);
2213 return -EFAULT;
2214 }
2215
2216 fd_install(fd, file);
2217
2218 return 0;
2219
2220 out_put_unused_fd:
2221 put_unused_fd(fd);
2222 out_free_le:
2223 lineevent_free(le);
2224 return ret;
2225 }
2226
gpio_v2_line_info_to_v1(struct gpio_v2_line_info * info_v2,struct gpioline_info * info_v1)2227 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2,
2228 struct gpioline_info *info_v1)
2229 {
2230 u64 flagsv2 = info_v2->flags;
2231
2232 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name));
2233 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer));
2234 info_v1->line_offset = info_v2->offset;
2235 info_v1->flags = 0;
2236
2237 if (flagsv2 & GPIO_V2_LINE_FLAG_USED)
2238 info_v1->flags |= GPIOLINE_FLAG_KERNEL;
2239
2240 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT)
2241 info_v1->flags |= GPIOLINE_FLAG_IS_OUT;
2242
2243 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
2244 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
2245
2246 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN)
2247 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN;
2248 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE)
2249 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE;
2250
2251 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)
2252 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
2253 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN)
2254 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
2255 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED)
2256 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
2257 }
2258
gpio_v2_line_info_changed_to_v1(struct gpio_v2_line_info_changed * lic_v2,struct gpioline_info_changed * lic_v1)2259 static void gpio_v2_line_info_changed_to_v1(
2260 struct gpio_v2_line_info_changed *lic_v2,
2261 struct gpioline_info_changed *lic_v1)
2262 {
2263 memset(lic_v1, 0, sizeof(*lic_v1));
2264 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info);
2265 lic_v1->timestamp = lic_v2->timestamp_ns;
2266 lic_v1->event_type = lic_v2->event_type;
2267 }
2268
2269 #endif /* CONFIG_GPIO_CDEV_V1 */
2270
gpio_desc_to_lineinfo(struct gpio_desc * desc,struct gpio_v2_line_info * info)2271 static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
2272 struct gpio_v2_line_info *info)
2273 {
2274 struct gpio_chip *gc = desc->gdev->chip;
2275 bool ok_for_pinctrl;
2276 unsigned long flags;
2277 u32 debounce_period_us;
2278 unsigned int num_attrs = 0;
2279
2280 memset(info, 0, sizeof(*info));
2281 info->offset = gpio_chip_hwgpio(desc);
2282
2283 /*
2284 * This function takes a mutex so we must check this before taking
2285 * the spinlock.
2286 *
2287 * FIXME: find a non-racy way to retrieve this information. Maybe a
2288 * lock common to both frameworks?
2289 */
2290 ok_for_pinctrl =
2291 pinctrl_gpio_can_use_line(gc->base + info->offset);
2292
2293 spin_lock_irqsave(&gpio_lock, flags);
2294
2295 if (desc->name)
2296 strscpy(info->name, desc->name, sizeof(info->name));
2297
2298 if (desc->label)
2299 strscpy(info->consumer, desc->label, sizeof(info->consumer));
2300
2301 /*
2302 * Userspace only need to know that the kernel is using this GPIO so
2303 * it can't use it.
2304 */
2305 info->flags = 0;
2306 if (test_bit(FLAG_REQUESTED, &desc->flags) ||
2307 test_bit(FLAG_IS_HOGGED, &desc->flags) ||
2308 test_bit(FLAG_USED_AS_IRQ, &desc->flags) ||
2309 test_bit(FLAG_EXPORT, &desc->flags) ||
2310 test_bit(FLAG_SYSFS, &desc->flags) ||
2311 !gpiochip_line_is_valid(gc, info->offset) ||
2312 !ok_for_pinctrl)
2313 info->flags |= GPIO_V2_LINE_FLAG_USED;
2314
2315 if (test_bit(FLAG_IS_OUT, &desc->flags))
2316 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
2317 else
2318 info->flags |= GPIO_V2_LINE_FLAG_INPUT;
2319
2320 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
2321 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
2322
2323 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
2324 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
2325 if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
2326 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
2327
2328 if (test_bit(FLAG_BIAS_DISABLE, &desc->flags))
2329 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
2330 if (test_bit(FLAG_PULL_DOWN, &desc->flags))
2331 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
2332 if (test_bit(FLAG_PULL_UP, &desc->flags))
2333 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
2334
2335 if (test_bit(FLAG_EDGE_RISING, &desc->flags))
2336 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
2337 if (test_bit(FLAG_EDGE_FALLING, &desc->flags))
2338 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
2339
2340 if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &desc->flags))
2341 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME;
2342 else if (test_bit(FLAG_EVENT_CLOCK_HTE, &desc->flags))
2343 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE;
2344
2345 debounce_period_us = READ_ONCE(desc->debounce_period_us);
2346 if (debounce_period_us) {
2347 info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
2348 info->attrs[num_attrs].debounce_period_us = debounce_period_us;
2349 num_attrs++;
2350 }
2351 info->num_attrs = num_attrs;
2352
2353 spin_unlock_irqrestore(&gpio_lock, flags);
2354 }
2355
2356 struct gpio_chardev_data {
2357 struct gpio_device *gdev;
2358 wait_queue_head_t wait;
2359 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32);
2360 struct notifier_block lineinfo_changed_nb;
2361 struct notifier_block device_unregistered_nb;
2362 unsigned long *watched_lines;
2363 #ifdef CONFIG_GPIO_CDEV_V1
2364 atomic_t watch_abi_version;
2365 #endif
2366 };
2367
chipinfo_get(struct gpio_chardev_data * cdev,void __user * ip)2368 static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip)
2369 {
2370 struct gpio_device *gdev = cdev->gdev;
2371 struct gpiochip_info chipinfo;
2372
2373 memset(&chipinfo, 0, sizeof(chipinfo));
2374
2375 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name));
2376 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label));
2377 chipinfo.lines = gdev->ngpio;
2378 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
2379 return -EFAULT;
2380 return 0;
2381 }
2382
2383 #ifdef CONFIG_GPIO_CDEV_V1
2384 /*
2385 * returns 0 if the versions match, else the previously selected ABI version
2386 */
lineinfo_ensure_abi_version(struct gpio_chardev_data * cdata,unsigned int version)2387 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata,
2388 unsigned int version)
2389 {
2390 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version);
2391
2392 if (abiv == version)
2393 return 0;
2394
2395 return abiv;
2396 }
2397
lineinfo_get_v1(struct gpio_chardev_data * cdev,void __user * ip,bool watch)2398 static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
2399 bool watch)
2400 {
2401 struct gpio_desc *desc;
2402 struct gpioline_info lineinfo;
2403 struct gpio_v2_line_info lineinfo_v2;
2404
2405 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2406 return -EFAULT;
2407
2408 /* this doubles as a range check on line_offset */
2409 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset);
2410 if (IS_ERR(desc))
2411 return PTR_ERR(desc);
2412
2413 if (watch) {
2414 if (lineinfo_ensure_abi_version(cdev, 1))
2415 return -EPERM;
2416
2417 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
2418 return -EBUSY;
2419 }
2420
2421 gpio_desc_to_lineinfo(desc, &lineinfo_v2);
2422 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
2423
2424 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2425 if (watch)
2426 clear_bit(lineinfo.line_offset, cdev->watched_lines);
2427 return -EFAULT;
2428 }
2429
2430 return 0;
2431 }
2432 #endif
2433
lineinfo_get(struct gpio_chardev_data * cdev,void __user * ip,bool watch)2434 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
2435 bool watch)
2436 {
2437 struct gpio_desc *desc;
2438 struct gpio_v2_line_info lineinfo;
2439
2440 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2441 return -EFAULT;
2442
2443 if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding)))
2444 return -EINVAL;
2445
2446 desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset);
2447 if (IS_ERR(desc))
2448 return PTR_ERR(desc);
2449
2450 if (watch) {
2451 #ifdef CONFIG_GPIO_CDEV_V1
2452 if (lineinfo_ensure_abi_version(cdev, 2))
2453 return -EPERM;
2454 #endif
2455 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
2456 return -EBUSY;
2457 }
2458 gpio_desc_to_lineinfo(desc, &lineinfo);
2459
2460 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2461 if (watch)
2462 clear_bit(lineinfo.offset, cdev->watched_lines);
2463 return -EFAULT;
2464 }
2465
2466 return 0;
2467 }
2468
lineinfo_unwatch(struct gpio_chardev_data * cdev,void __user * ip)2469 static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip)
2470 {
2471 __u32 offset;
2472
2473 if (copy_from_user(&offset, ip, sizeof(offset)))
2474 return -EFAULT;
2475
2476 if (offset >= cdev->gdev->ngpio)
2477 return -EINVAL;
2478
2479 if (!test_and_clear_bit(offset, cdev->watched_lines))
2480 return -EBUSY;
2481
2482 return 0;
2483 }
2484
2485 /*
2486 * gpio_ioctl() - ioctl handler for the GPIO chardev
2487 */
gpio_ioctl(struct file * file,unsigned int cmd,unsigned long arg)2488 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2489 {
2490 struct gpio_chardev_data *cdev = file->private_data;
2491 struct gpio_device *gdev = cdev->gdev;
2492 void __user *ip = (void __user *)arg;
2493
2494 /* We fail any subsequent ioctl():s when the chip is gone */
2495 if (!gdev->chip)
2496 return -ENODEV;
2497
2498 /* Fill in the struct and pass to userspace */
2499 switch (cmd) {
2500 case GPIO_GET_CHIPINFO_IOCTL:
2501 return chipinfo_get(cdev, ip);
2502 #ifdef CONFIG_GPIO_CDEV_V1
2503 case GPIO_GET_LINEHANDLE_IOCTL:
2504 return linehandle_create(gdev, ip);
2505 case GPIO_GET_LINEEVENT_IOCTL:
2506 return lineevent_create(gdev, ip);
2507 case GPIO_GET_LINEINFO_IOCTL:
2508 return lineinfo_get_v1(cdev, ip, false);
2509 case GPIO_GET_LINEINFO_WATCH_IOCTL:
2510 return lineinfo_get_v1(cdev, ip, true);
2511 #endif /* CONFIG_GPIO_CDEV_V1 */
2512 case GPIO_V2_GET_LINEINFO_IOCTL:
2513 return lineinfo_get(cdev, ip, false);
2514 case GPIO_V2_GET_LINEINFO_WATCH_IOCTL:
2515 return lineinfo_get(cdev, ip, true);
2516 case GPIO_V2_GET_LINE_IOCTL:
2517 return linereq_create(gdev, ip);
2518 case GPIO_GET_LINEINFO_UNWATCH_IOCTL:
2519 return lineinfo_unwatch(cdev, ip);
2520 default:
2521 return -EINVAL;
2522 }
2523 }
2524
2525 #ifdef CONFIG_COMPAT
gpio_ioctl_compat(struct file * file,unsigned int cmd,unsigned long arg)2526 static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
2527 unsigned long arg)
2528 {
2529 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2530 }
2531 #endif
2532
lineinfo_changed_notify(struct notifier_block * nb,unsigned long action,void * data)2533 static int lineinfo_changed_notify(struct notifier_block *nb,
2534 unsigned long action, void *data)
2535 {
2536 struct gpio_chardev_data *cdev =
2537 container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
2538 struct gpio_v2_line_info_changed chg;
2539 struct gpio_desc *desc = data;
2540 int ret;
2541
2542 if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines))
2543 return NOTIFY_DONE;
2544
2545 memset(&chg, 0, sizeof(chg));
2546 chg.event_type = action;
2547 chg.timestamp_ns = ktime_get_ns();
2548 gpio_desc_to_lineinfo(desc, &chg.info);
2549
2550 ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
2551 if (ret)
2552 wake_up_poll(&cdev->wait, EPOLLIN);
2553 else
2554 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");
2555
2556 return NOTIFY_OK;
2557 }
2558
gpio_device_unregistered_notify(struct notifier_block * nb,unsigned long action,void * data)2559 static int gpio_device_unregistered_notify(struct notifier_block *nb,
2560 unsigned long action, void *data)
2561 {
2562 struct gpio_chardev_data *cdev = container_of(nb,
2563 struct gpio_chardev_data,
2564 device_unregistered_nb);
2565
2566 wake_up_poll(&cdev->wait, EPOLLIN | EPOLLERR);
2567
2568 return NOTIFY_OK;
2569 }
2570
lineinfo_watch_poll_unlocked(struct file * file,struct poll_table_struct * pollt)2571 static __poll_t lineinfo_watch_poll_unlocked(struct file *file,
2572 struct poll_table_struct *pollt)
2573 {
2574 struct gpio_chardev_data *cdev = file->private_data;
2575 __poll_t events = 0;
2576
2577 if (!cdev->gdev->chip)
2578 return EPOLLHUP | EPOLLERR;
2579
2580 poll_wait(file, &cdev->wait, pollt);
2581
2582 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events,
2583 &cdev->wait.lock))
2584 events = EPOLLIN | EPOLLRDNORM;
2585
2586 return events;
2587 }
2588
lineinfo_watch_poll(struct file * file,struct poll_table_struct * pollt)2589 static __poll_t lineinfo_watch_poll(struct file *file,
2590 struct poll_table_struct *pollt)
2591 {
2592 struct gpio_chardev_data *cdev = file->private_data;
2593
2594 return call_poll_locked(file, pollt, cdev->gdev,
2595 lineinfo_watch_poll_unlocked);
2596 }
2597
lineinfo_watch_read_unlocked(struct file * file,char __user * buf,size_t count,loff_t * off)2598 static ssize_t lineinfo_watch_read_unlocked(struct file *file, char __user *buf,
2599 size_t count, loff_t *off)
2600 {
2601 struct gpio_chardev_data *cdev = file->private_data;
2602 struct gpio_v2_line_info_changed event;
2603 ssize_t bytes_read = 0;
2604 int ret;
2605 size_t event_size;
2606
2607 if (!cdev->gdev->chip)
2608 return -ENODEV;
2609
2610 #ifndef CONFIG_GPIO_CDEV_V1
2611 event_size = sizeof(struct gpio_v2_line_info_changed);
2612 if (count < event_size)
2613 return -EINVAL;
2614 #endif
2615
2616 do {
2617 spin_lock(&cdev->wait.lock);
2618 if (kfifo_is_empty(&cdev->events)) {
2619 if (bytes_read) {
2620 spin_unlock(&cdev->wait.lock);
2621 return bytes_read;
2622 }
2623
2624 if (file->f_flags & O_NONBLOCK) {
2625 spin_unlock(&cdev->wait.lock);
2626 return -EAGAIN;
2627 }
2628
2629 ret = wait_event_interruptible_locked(cdev->wait,
2630 !kfifo_is_empty(&cdev->events));
2631 if (ret) {
2632 spin_unlock(&cdev->wait.lock);
2633 return ret;
2634 }
2635 }
2636 #ifdef CONFIG_GPIO_CDEV_V1
2637 /* must be after kfifo check so watch_abi_version is set */
2638 if (atomic_read(&cdev->watch_abi_version) == 2)
2639 event_size = sizeof(struct gpio_v2_line_info_changed);
2640 else
2641 event_size = sizeof(struct gpioline_info_changed);
2642 if (count < event_size) {
2643 spin_unlock(&cdev->wait.lock);
2644 return -EINVAL;
2645 }
2646 #endif
2647 ret = kfifo_out(&cdev->events, &event, 1);
2648 spin_unlock(&cdev->wait.lock);
2649 if (ret != 1) {
2650 ret = -EIO;
2651 break;
2652 /* We should never get here. See lineevent_read(). */
2653 }
2654
2655 #ifdef CONFIG_GPIO_CDEV_V1
2656 if (event_size == sizeof(struct gpio_v2_line_info_changed)) {
2657 if (copy_to_user(buf + bytes_read, &event, event_size))
2658 return -EFAULT;
2659 } else {
2660 struct gpioline_info_changed event_v1;
2661
2662 gpio_v2_line_info_changed_to_v1(&event, &event_v1);
2663 if (copy_to_user(buf + bytes_read, &event_v1,
2664 event_size))
2665 return -EFAULT;
2666 }
2667 #else
2668 if (copy_to_user(buf + bytes_read, &event, event_size))
2669 return -EFAULT;
2670 #endif
2671 bytes_read += event_size;
2672 } while (count >= bytes_read + sizeof(event));
2673
2674 return bytes_read;
2675 }
2676
lineinfo_watch_read(struct file * file,char __user * buf,size_t count,loff_t * off)2677 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
2678 size_t count, loff_t *off)
2679 {
2680 struct gpio_chardev_data *cdev = file->private_data;
2681
2682 return call_read_locked(file, buf, count, off, cdev->gdev,
2683 lineinfo_watch_read_unlocked);
2684 }
2685
2686 /**
2687 * gpio_chrdev_open() - open the chardev for ioctl operations
2688 * @inode: inode for this chardev
2689 * @file: file struct for storing private data
2690 * Returns 0 on success
2691 */
gpio_chrdev_open(struct inode * inode,struct file * file)2692 static int gpio_chrdev_open(struct inode *inode, struct file *file)
2693 {
2694 struct gpio_device *gdev = container_of(inode->i_cdev,
2695 struct gpio_device, chrdev);
2696 struct gpio_chardev_data *cdev;
2697 int ret = -ENOMEM;
2698
2699 down_read(&gdev->sem);
2700
2701 /* Fail on open if the backing gpiochip is gone */
2702 if (!gdev->chip) {
2703 ret = -ENODEV;
2704 goto out_unlock;
2705 }
2706
2707 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
2708 if (!cdev)
2709 goto out_unlock;
2710
2711 cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL);
2712 if (!cdev->watched_lines)
2713 goto out_free_cdev;
2714
2715 init_waitqueue_head(&cdev->wait);
2716 INIT_KFIFO(cdev->events);
2717 cdev->gdev = gpio_device_get(gdev);
2718
2719 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
2720 ret = blocking_notifier_chain_register(&gdev->line_state_notifier,
2721 &cdev->lineinfo_changed_nb);
2722 if (ret)
2723 goto out_free_bitmap;
2724
2725 cdev->device_unregistered_nb.notifier_call =
2726 gpio_device_unregistered_notify;
2727 ret = blocking_notifier_chain_register(&gdev->device_notifier,
2728 &cdev->device_unregistered_nb);
2729 if (ret)
2730 goto out_unregister_line_notifier;
2731
2732 file->private_data = cdev;
2733
2734 ret = nonseekable_open(inode, file);
2735 if (ret)
2736 goto out_unregister_device_notifier;
2737
2738 up_read(&gdev->sem);
2739
2740 return ret;
2741
2742 out_unregister_device_notifier:
2743 blocking_notifier_chain_unregister(&gdev->device_notifier,
2744 &cdev->device_unregistered_nb);
2745 out_unregister_line_notifier:
2746 blocking_notifier_chain_unregister(&gdev->line_state_notifier,
2747 &cdev->lineinfo_changed_nb);
2748 out_free_bitmap:
2749 gpio_device_put(gdev);
2750 bitmap_free(cdev->watched_lines);
2751 out_free_cdev:
2752 kfree(cdev);
2753 out_unlock:
2754 up_read(&gdev->sem);
2755 return ret;
2756 }
2757
2758 /**
2759 * gpio_chrdev_release() - close chardev after ioctl operations
2760 * @inode: inode for this chardev
2761 * @file: file struct for storing private data
2762 * Returns 0 on success
2763 */
gpio_chrdev_release(struct inode * inode,struct file * file)2764 static int gpio_chrdev_release(struct inode *inode, struct file *file)
2765 {
2766 struct gpio_chardev_data *cdev = file->private_data;
2767 struct gpio_device *gdev = cdev->gdev;
2768
2769 bitmap_free(cdev->watched_lines);
2770 blocking_notifier_chain_unregister(&gdev->device_notifier,
2771 &cdev->device_unregistered_nb);
2772 blocking_notifier_chain_unregister(&gdev->line_state_notifier,
2773 &cdev->lineinfo_changed_nb);
2774 gpio_device_put(gdev);
2775 kfree(cdev);
2776
2777 return 0;
2778 }
2779
2780 static const struct file_operations gpio_fileops = {
2781 .release = gpio_chrdev_release,
2782 .open = gpio_chrdev_open,
2783 .poll = lineinfo_watch_poll,
2784 .read = lineinfo_watch_read,
2785 .owner = THIS_MODULE,
2786 .llseek = no_llseek,
2787 .unlocked_ioctl = gpio_ioctl,
2788 #ifdef CONFIG_COMPAT
2789 .compat_ioctl = gpio_ioctl_compat,
2790 #endif
2791 };
2792
gpiolib_cdev_register(struct gpio_device * gdev,dev_t devt)2793 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
2794 {
2795 int ret;
2796
2797 cdev_init(&gdev->chrdev, &gpio_fileops);
2798 gdev->chrdev.owner = THIS_MODULE;
2799 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
2800
2801 ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
2802 if (ret)
2803 return ret;
2804
2805 chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
2806 MAJOR(devt), gdev->id);
2807
2808 return 0;
2809 }
2810
gpiolib_cdev_unregister(struct gpio_device * gdev)2811 void gpiolib_cdev_unregister(struct gpio_device *gdev)
2812 {
2813 cdev_device_del(&gdev->chrdev, &gdev->dev);
2814 blocking_notifier_call_chain(&gdev->device_notifier, 0, NULL);
2815 }
2816
