aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/media/common/ir-keytable.c
blob: ceef0e82fb4b649f14c618c431483a552606a4b8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
/* ir-register.c - handle IR scancode->keycode tables
 *
 * Copyright (C) 2009 by Mauro Carvalho Chehab <mchehab@redhat.com>
 */

#include <linux/usb/input.h>

#include <media/ir-common.h>

#define IR_TAB_MIN_SIZE	32
#define IR_TAB_MAX_SIZE	1024

/**
 * ir_seek_table() - returns the element order on the table
 * @rc_tab:	the ir_scancode_table with the keymap to be used
 * @scancode:	the scancode that we're seeking
 *
 * This routine is used by the input routines when a key is pressed at the
 * IR. The scancode is received and needs to be converted into a keycode.
 * If the key is not found, it returns KEY_UNKNOWN. Otherwise, returns the
 * corresponding keycode from the table.
 */
static int ir_seek_table(struct ir_scancode_table *rc_tab, u32 scancode)
{
	int rc;
	unsigned long flags;
	struct ir_scancode *keymap = rc_tab->scan;

	spin_lock_irqsave(&rc_tab->lock, flags);

	/* FIXME: replace it by a binary search */

	for (rc = 0; rc < rc_tab->size; rc++)
		if (keymap[rc].scancode == scancode)
			goto exit;

	/* Not found */
	rc = -EINVAL;

exit:
	spin_unlock_irqrestore(&rc_tab->lock, flags);
	return rc;
}

/**
 * ir_roundup_tablesize() - gets an optimum value for the table size
 * @n_elems:		minimum number of entries to store keycodes
 *
 * This routine is used to choose the keycode table size.
 *
 * In order to have some empty space for new keycodes,
 * and knowing in advance that kmalloc allocates only power of two
 * segments, it optimizes the allocated space to have some spare space
 * for those new keycodes by using the maximum number of entries that
 * will be effectively be allocated by kmalloc.
 * In order to reduce the quantity of table resizes, it has a minimum
 * table size of IR_TAB_MIN_SIZE.
 */
int ir_roundup_tablesize(int n_elems)
{
	size_t size;

	if (n_elems < IR_TAB_MIN_SIZE)
		n_elems = IR_TAB_MIN_SIZE;

	/*
	 * As kmalloc only allocates sizes of power of two, get as
	 * much entries as possible for the allocated memory segment
	 */
	size = roundup_pow_of_two(n_elems * sizeof(struct ir_scancode));
	n_elems = size / sizeof(struct ir_scancode);

	return n_elems;
}

/**
 * ir_copy_table() - copies a keytable, discarding the unused entries
 * @destin:	destin table
 * @origin:	origin table
 *
 * Copies all entries where the keycode is not KEY_UNKNOWN/KEY_RESERVED
 */

int ir_copy_table(struct ir_scancode_table *destin,
		 const struct ir_scancode_table *origin)
{
	int i, j = 0;

	for (i = 0; i < origin->size; i++) {
		if (origin->scan[i].keycode == KEY_UNKNOWN ||
		   origin->scan[i].keycode == KEY_RESERVED)
			continue;

		memcpy(&destin->scan[j], &origin->scan[i], sizeof(struct ir_scancode));
		j++;
	}
	destin->size = j;

	IR_dprintk(1, "Copied %d scancodes to the new keycode table\n", destin->size);

	return 0;
}

/**
 * ir_getkeycode() - get a keycode at the evdev scancode ->keycode table
 * @dev:	the struct input_dev device descriptor
 * @scancode:	the desired scancode
 * @keycode:	the keycode to be retorned.
 *
 * This routine is used to handle evdev EVIOCGKEY ioctl.
 * If the key is not found, returns -EINVAL, otherwise, returns 0.
 */
static int ir_getkeycode(struct input_dev *dev,
			 int scancode, int *keycode)
{
	int elem;
	struct ir_scancode_table *rc_tab = input_get_drvdata(dev);

	elem = ir_seek_table(rc_tab, scancode);
	if (elem >= 0) {
		*keycode = rc_tab->scan[elem].keycode;
		return 0;
	}

	/*
	 * Scancode not found and table can't be expanded
	 */
	if (elem < 0 && rc_tab->size == IR_TAB_MAX_SIZE)
		return -EINVAL;

	/*
	 * If is there extra space, returns KEY_RESERVED,
	 * otherwise, input core won't let ir_setkeycode to work
	 */
	*keycode = KEY_RESERVED;
	return 0;
}


/**
 * ir_is_resize_needed() - Check if the table needs rezise
 * @table:		keycode table that may need to resize
 * @n_elems:		minimum number of entries to store keycodes
 *
 * Considering that kmalloc uses power of two storage areas, this
 * routine detects if the real alloced size will change. If not, it
 * just returns without doing nothing. Otherwise, it will extend or
 * reduce the table size to meet the new needs.
 *
 * It returns 0 if no resize is needed, 1 otherwise.
 */
static int ir_is_resize_needed(struct ir_scancode_table *table, int n_elems)
{
	int cur_size = ir_roundup_tablesize(table->size);
	int new_size = ir_roundup_tablesize(n_elems);

	if (cur_size == new_size)
		return 0;

	/* Resize is needed */
	return 1;
}

/**
 * ir_delete_key() - remove a keycode from the table
 * @rc_tab:		keycode table
 * @elem:		element to be removed
 *
 */
static void ir_delete_key(struct ir_scancode_table *rc_tab, int elem)
{
	unsigned long flags = 0;
	int newsize = rc_tab->size - 1;
	int resize = ir_is_resize_needed(rc_tab, newsize);
	struct ir_scancode *oldkeymap = rc_tab->scan;
	struct ir_scancode *newkeymap;

	if (resize) {
		newkeymap = kzalloc(ir_roundup_tablesize(newsize) *
				    sizeof(*newkeymap), GFP_ATOMIC);

		/* There's no memory for resize. Keep the old table */
		if (!newkeymap)
			resize = 0;
	}

	if (!resize) {
		newkeymap = oldkeymap;

		/* We'll modify the live table. Lock it */
		spin_lock_irqsave(&rc_tab->lock, flags);
	}

	/*
	 * Copy the elements before the one that will be deleted
	 * if (!resize), both oldkeymap and newkeymap points
	 * to the same place, so, there's no need to copy
	 */
	if (resize && elem > 0)
		memcpy(newkeymap, oldkeymap,
		       elem * sizeof(*newkeymap));

	/*
	 * Copy the other elements overwriting the element to be removed
	 * This operation applies to both resize and non-resize case
	 */
	if (elem < newsize)
		memcpy(&newkeymap[elem], &oldkeymap[elem + 1],
		       (newsize - elem) * sizeof(*newkeymap));

	if (resize) {
		/*
		 * As the copy happened to a temporary table, only here
		 * it needs to lock while replacing the table pointers
		 * to use the new table
		 */
		spin_lock_irqsave(&rc_tab->lock, flags);
		rc_tab->size = newsize;
		rc_tab->scan = newkeymap;
		spin_unlock_irqrestore(&rc_tab->lock, flags);

		/* Frees the old keytable */
		kfree(oldkeymap);
	} else {
		rc_tab->size = newsize;
		spin_unlock_irqrestore(&rc_tab->lock, flags);
	}
}

/**
 * ir_insert_key() - insert a keycode at the table
 * @rc_tab:		keycode table
 * @scancode:	the desired scancode
 * @keycode:	the keycode to be retorned.
 *
 */
static int ir_insert_key(struct ir_scancode_table *rc_tab,
			  int scancode, int keycode)
{
	unsigned long flags;
	int elem = rc_tab->size;
	int newsize = rc_tab->size + 1;
	int resize = ir_is_resize_needed(rc_tab, newsize);
	struct ir_scancode *oldkeymap = rc_tab->scan;
	struct ir_scancode *newkeymap;

	if (resize) {
		newkeymap = kzalloc(ir_roundup_tablesize(newsize) *
				    sizeof(*newkeymap), GFP_ATOMIC);
		if (!newkeymap)
			return -ENOMEM;

		memcpy(newkeymap, oldkeymap,
		       rc_tab->size * sizeof(*newkeymap));
	} else
		newkeymap  = oldkeymap;

	/* Stores the new code at the table */
	IR_dprintk(1, "#%d: New scan 0x%04x with key 0x%04x\n",
		   rc_tab->size, scancode, keycode);

	spin_lock_irqsave(&rc_tab->lock, flags);
	rc_tab->size = newsize;
	if (resize) {
		rc_tab->scan = newkeymap;
		kfree(oldkeymap);
	}
	newkeymap[elem].scancode = scancode;
	newkeymap[elem].keycode  = keycode;
	spin_unlock_irqrestore(&rc_tab->lock, flags);

	return 0;
}

/**
 * ir_setkeycode() - set a keycode at the evdev scancode ->keycode table
 * @dev:	the struct input_dev device descriptor
 * @scancode:	the desired scancode
 * @keycode:	the keycode to be retorned.
 *
 * This routine is used to handle evdev EVIOCSKEY ioctl.
 * There's one caveat here: how can we increase the size of the table?
 * If the key is not found, returns -EINVAL, otherwise, returns 0.
 */
static int ir_setkeycode(struct input_dev *dev,
			 int scancode, int keycode)
{
	int rc = 0;
	struct ir_scancode_table *rc_tab = input_get_drvdata(dev);
	struct ir_scancode *keymap = rc_tab->scan;
	unsigned long flags;

	/*
	 * Handle keycode table deletions
	 *
	 * If userspace is adding a KEY_UNKNOWN or KEY_RESERVED,
	 * deal as a trial to remove an existing scancode attribution
	 * if table become too big, reduce it to save space
	 */
	if (keycode == KEY_UNKNOWN || keycode == KEY_RESERVED) {
		rc = ir_seek_table(rc_tab, scancode);
		if (rc < 0)
			return 0;

		IR_dprintk(1, "#%d: Deleting scan 0x%04x\n", rc, scancode);
		clear_bit(keymap[rc].keycode, dev->keybit);
		ir_delete_key(rc_tab, rc);

		return 0;
	}

	/*
	 * Handle keycode replacements
	 *
	 * If the scancode exists, just replace by the new value
	 */
	rc = ir_seek_table(rc_tab, scancode);
	if (rc >= 0) {
		IR_dprintk(1, "#%d: Replacing scan 0x%04x with key 0x%04x\n",
			rc, scancode, keycode);

		clear_bit(keymap[rc].keycode, dev->keybit);

		spin_lock_irqsave(&rc_tab->lock, flags);
		keymap[rc].keycode = keycode;
		spin_unlock_irqrestore(&rc_tab->lock, flags);

		set_bit(keycode, dev->keybit);

		return 0;
	}

	/*
	 * Handle new scancode inserts
	 *
	 * reallocate table if needed and insert a new keycode
	 */

	/* Avoid growing the table indefinitely */
	if (rc_tab->size + 1 > IR_TAB_MAX_SIZE)
		return -EINVAL;

	rc = ir_insert_key(rc_tab, scancode, keycode);
	if (rc < 0)
		return rc;
	set_bit(keycode, dev->keybit);

	return 0;
}

/**
 * ir_g_keycode_from_table() - gets the keycode that corresponds to a scancode
 * @input_dev:	the struct input_dev descriptor of the device
 * @scancode:	the scancode that we're seeking
 *
 * This routine is used by the input routines when a key is pressed at the
 * IR. The scancode is received and needs to be converted into a keycode.
 * If the key is not found, it returns KEY_UNKNOWN. Otherwise, returns the
 * corresponding keycode from the table.
 */
u32 ir_g_keycode_from_table(struct input_dev *dev, u32 scancode)
{
	struct ir_scancode_table *rc_tab = input_get_drvdata(dev);
	struct ir_scancode *keymap = rc_tab->scan;
	int elem;

	elem = ir_seek_table(rc_tab, scancode);
	if (elem >= 0) {
		IR_dprintk(1, "%s: scancode 0x%04x keycode 0x%02x\n",
			   dev->name, scancode, keymap[elem].keycode);

		return rc_tab->scan[elem].keycode;
	}

	printk(KERN_INFO "%s: unknown key for scancode 0x%04x\n",
	       dev->name, scancode);

	/* Reports userspace that an unknown keycode were got */
	return KEY_RESERVED;
}

/**
 * ir_set_keycode_table() - sets the IR keycode table and add the handlers
 *			    for keymap table get/set
 * @input_dev:	the struct input_dev descriptor of the device
 * @rc_tab:	the struct ir_scancode_table table of scancode/keymap
 *
 * This routine is used to initialize the input infrastructure to work with
 * an IR.
 * It should be called before registering the IR device.
 */
int ir_set_keycode_table(struct input_dev *input_dev,
			 struct ir_scancode_table *rc_tab)
{
	struct ir_scancode *keymap = rc_tab->scan;
	int i;

	spin_lock_init(&rc_tab->lock);

	if (rc_tab->scan == NULL || !rc_tab->size)
		return -EINVAL;

	/* set the bits for the keys */
	IR_dprintk(1, "key map size: %d\n", rc_tab->size);
	for (i = 0; i < rc_tab->size; i++) {
		IR_dprintk(1, "#%d: setting bit for keycode 0x%04x\n",
			i, keymap[i].keycode);
		set_bit(keymap[i].keycode, input_dev->keybit);
	}

	input_dev->getkeycode = ir_getkeycode;
	input_dev->setkeycode = ir_setkeycode;
	input_set_drvdata(input_dev, rc_tab);

	return 0;
}

void ir_input_free(struct input_dev *dev)
{
	struct ir_scancode_table *rc_tab = input_get_drvdata(dev);

	if (!rc_tab)
		return;

	IR_dprintk(1, "Freed keycode table\n");

	rc_tab->size = 0;
	kfree(rc_tab->scan);
	rc_tab->scan = NULL;
}
EXPORT_SYMBOL_GPL(ir_input_free);

Privacy Policy