Free Electrons

Embedded Linux Experts

  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
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
/*
 *  Driver for the Gravis Grip Multiport, a gamepad "hub" that
 *  connects up to four 9-pin digital gamepads/joysticks.
 *  Driver tested on SMP and UP kernel versions 2.4.18-4 and 2.4.18-5.
 *
 *  Thanks to Chris Gassib for helpful advice.
 *
 *  Copyright (c)      2002 Brian Bonnlander, Bill Soudan
 *  Copyright (c) 1998-2000 Vojtech Pavlik
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/gameport.h>
#include <linux/input.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/jiffies.h>

#define DRIVER_DESC	"Gravis Grip Multiport driver"

MODULE_AUTHOR("Brian Bonnlander");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

#ifdef GRIP_DEBUG
#define dbg(format, arg...) printk(KERN_ERR __FILE__ ": " format "\n" , ## arg)
#else
#define dbg(format, arg...) do {} while (0)
#endif

#define GRIP_MAX_PORTS	4
/*
 * Grip multiport state
 */

struct grip_port {
	struct input_dev *dev;
	int mode;
	int registered;

	/* individual gamepad states */
	int buttons;
	int xaxes;
	int yaxes;
	int dirty;     /* has the state been updated? */
};

struct grip_mp {
	struct gameport *gameport;
	struct grip_port *port[GRIP_MAX_PORTS];
	int reads;
	int bads;
};

/*
 * Multiport packet interpretation
 */

#define PACKET_FULL          0x80000000       /* packet is full                        */
#define PACKET_IO_FAST       0x40000000       /* 3 bits per gameport read              */
#define PACKET_IO_SLOW       0x20000000       /* 1 bit per gameport read               */
#define PACKET_MP_MORE       0x04000000       /* multiport wants to send more          */
#define PACKET_MP_DONE       0x02000000       /* multiport done sending                */

/*
 * Packet status code interpretation
 */

#define IO_GOT_PACKET        0x0100           /* Got a packet                           */
#define IO_MODE_FAST         0x0200           /* Used 3 data bits per gameport read     */
#define IO_SLOT_CHANGE       0x0800           /* Multiport physical slot status changed */
#define IO_DONE              0x1000           /* Multiport is done sending packets      */
#define IO_RETRY             0x4000           /* Try again later to get packet          */
#define IO_RESET             0x8000           /* Force multiport to resend all packets  */

/*
 * Gamepad configuration data.  Other 9-pin digital joystick devices
 * may work with the multiport, so this may not be an exhaustive list!
 * Commodore 64 joystick remains untested.
 */

#define GRIP_INIT_DELAY         2000          /*  2 ms */

#define GRIP_MODE_NONE		0
#define GRIP_MODE_RESET         1
#define GRIP_MODE_GP		2
#define GRIP_MODE_C64		3

static const int grip_btn_gp[]  = { BTN_TR, BTN_TL, BTN_A, BTN_B, BTN_C, BTN_X, BTN_Y, BTN_Z, -1 };
static const int grip_btn_c64[] = { BTN_JOYSTICK, -1 };

static const int grip_abs_gp[]  = { ABS_X, ABS_Y, -1 };
static const int grip_abs_c64[] = { ABS_X, ABS_Y, -1 };

static const int *grip_abs[] = { NULL, NULL, grip_abs_gp, grip_abs_c64 };
static const int *grip_btn[] = { NULL, NULL, grip_btn_gp, grip_btn_c64 };

static const char *grip_name[] = { NULL, NULL, "Gravis Grip Pad", "Commodore 64 Joystick" };

static const int init_seq[] = {
	1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1,
	1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1,
	1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1,
	0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1 };

/* Maps multiport directional values to X,Y axis values (each axis encoded in 3 bits) */

static const int axis_map[] = { 5, 9, 1, 5, 6, 10, 2, 6, 4, 8, 0, 4, 5, 9, 1, 5 };

static int register_slot(int i, struct grip_mp *grip);

/*
 * Returns whether an odd or even number of bits are on in pkt.
 */

static int bit_parity(u32 pkt)
{
	int x = pkt ^ (pkt >> 16);
	x ^= x >> 8;
	x ^= x >> 4;
	x ^= x >> 2;
	x ^= x >> 1;
	return x & 1;
}

/*
 * Poll gameport; return true if all bits set in 'onbits' are on and
 * all bits set in 'offbits' are off.
 */

static inline int poll_until(u8 onbits, u8 offbits, int u_sec, struct gameport* gp, u8 *data)
{
	int i, nloops;

	nloops = gameport_time(gp, u_sec);
	for (i = 0; i < nloops; i++) {
		*data = gameport_read(gp);
		if ((*data & onbits) == onbits &&
		    (~(*data) & offbits) == offbits)
			return 1;
	}
	dbg("gameport timed out after %d microseconds.\n", u_sec);
	return 0;
}

/*
 * Gets a 28-bit packet from the multiport.
 *
 * After getting a packet successfully, commands encoded by sendcode may
 * be sent to the multiport.
 *
 * The multiport clock value is reflected in gameport bit B4.
 *
 * Returns a packet status code indicating whether packet is valid, the transfer
 * mode, and any error conditions.
 *
 * sendflags:      current I/O status
 * sendcode:   data to send to the multiport if sendflags is nonzero
 */

static int mp_io(struct gameport* gameport, int sendflags, int sendcode, u32 *packet)
{
	u8  raw_data;            /* raw data from gameport */
	u8  data_mask;           /* packet data bits from raw_data */
	u32 pkt;                 /* packet temporary storage */
	int bits_per_read;       /* num packet bits per gameport read */
	int portvals = 0;        /* used for port value sanity check */
	int i;

	/* Gameport bits B0, B4, B5 should first be off, then B4 should come on. */

	*packet = 0;
	raw_data = gameport_read(gameport);
	if (raw_data & 1)
		return IO_RETRY;

	for (i = 0; i < 64; i++) {
		raw_data = gameport_read(gameport);
		portvals |= 1 << ((raw_data >> 4) & 3); /* Demux B4, B5 */
	}

	if (portvals == 1) {                            /* B4, B5 off */
		raw_data = gameport_read(gameport);
		portvals = raw_data & 0xf0;

		if (raw_data & 0x31)
			return IO_RESET;
		gameport_trigger(gameport);

		if (!poll_until(0x10, 0, 308, gameport, &raw_data))
			return IO_RESET;
	} else
		return IO_RETRY;

	/* Determine packet transfer mode and prepare for packet construction. */

	if (raw_data & 0x20) {                 /* 3 data bits/read */
		portvals |= raw_data >> 4;     /* Compare B4-B7 before & after trigger */

		if (portvals != 0xb)
			return 0;
		data_mask = 7;
		bits_per_read = 3;
		pkt = (PACKET_FULL | PACKET_IO_FAST) >> 28;
	} else {                                 /* 1 data bit/read */
		data_mask = 1;
		bits_per_read = 1;
		pkt = (PACKET_FULL | PACKET_IO_SLOW) >> 28;
	}

	/* Construct a packet.  Final data bits must be zero. */

	while (1) {
		if (!poll_until(0, 0x10, 77, gameport, &raw_data))
			return IO_RESET;
		raw_data = (raw_data >> 5) & data_mask;

		if (pkt & PACKET_FULL)
			break;
		pkt = (pkt << bits_per_read) | raw_data;

		if (!poll_until(0x10, 0, 77, gameport, &raw_data))
			return IO_RESET;
	}

	if (raw_data)
		return IO_RESET;

	/* If 3 bits/read used, drop from 30 bits to 28. */

	if (bits_per_read == 3) {
		pkt = (pkt & 0xffff0000) | ((pkt << 1) & 0xffff);
		pkt = (pkt >> 2) | 0xf0000000;
	}

	if (bit_parity(pkt) == 1)
		return IO_RESET;

	/* Acknowledge packet receipt */

	if (!poll_until(0x30, 0, 77, gameport, &raw_data))
		return IO_RESET;

	raw_data = gameport_read(gameport);

	if (raw_data & 1)
		return IO_RESET;

	gameport_trigger(gameport);

	if (!poll_until(0, 0x20, 77, gameport, &raw_data))
		return IO_RESET;

        /* Return if we just wanted the packet or multiport wants to send more */

	*packet = pkt;
	if ((sendflags == 0) || ((sendflags & IO_RETRY) && !(pkt & PACKET_MP_DONE)))
		return IO_GOT_PACKET;

	if (pkt & PACKET_MP_MORE)
		return IO_GOT_PACKET | IO_RETRY;

	/* Multiport is done sending packets and is ready to receive data */

	if (!poll_until(0x20, 0, 77, gameport, &raw_data))
		return IO_GOT_PACKET | IO_RESET;

	raw_data = gameport_read(gameport);
	if (raw_data & 1)
		return IO_GOT_PACKET | IO_RESET;

	/* Trigger gameport based on bits in sendcode */

	gameport_trigger(gameport);
	do {
		if (!poll_until(0x20, 0x10, 116, gameport, &raw_data))
			return IO_GOT_PACKET | IO_RESET;

		if (!poll_until(0x30, 0, 193, gameport, &raw_data))
			return IO_GOT_PACKET | IO_RESET;

		if (raw_data & 1)
			return IO_GOT_PACKET | IO_RESET;

		if (sendcode & 1)
			gameport_trigger(gameport);

		sendcode >>= 1;
	} while (sendcode);

	return IO_GOT_PACKET | IO_MODE_FAST;
}

/*
 * Disables and restores interrupts for mp_io(), which does the actual I/O.
 */

static int multiport_io(struct gameport* gameport, int sendflags, int sendcode, u32 *packet)
{
	int status;
	unsigned long flags;

	local_irq_save(flags);
	status = mp_io(gameport, sendflags, sendcode, packet);
	local_irq_restore(flags);

	return status;
}

/*
 * Puts multiport into digital mode.  Multiport LED turns green.
 *
 * Returns true if a valid digital packet was received, false otherwise.
 */

static int dig_mode_start(struct gameport *gameport, u32 *packet)
{
	int i;
	int flags, tries = 0, bads = 0;

	for (i = 0; i < ARRAY_SIZE(init_seq); i++) {     /* Send magic sequence */
		if (init_seq[i])
			gameport_trigger(gameport);
		udelay(GRIP_INIT_DELAY);
	}

	for (i = 0; i < 16; i++)            /* Wait for multiport to settle */
		udelay(GRIP_INIT_DELAY);

	while (tries < 64 && bads < 8) {    /* Reset multiport and try getting a packet */

		flags = multiport_io(gameport, IO_RESET, 0x27, packet);

		if (flags & IO_MODE_FAST)
			return 1;

		if (flags & IO_RETRY)
			tries++;
		else
			bads++;
	}
	return 0;
}

/*
 * Packet structure: B0-B15   => gamepad state
 *                   B16-B20  => gamepad device type
 *                   B21-B24  => multiport slot index (1-4)
 *
 * Known device types: 0x1f (grip pad), 0x0 (no device).  Others may exist.
 *
 * Returns the packet status.
 */

static int get_and_decode_packet(struct grip_mp *grip, int flags)
{
	struct grip_port *port;
	u32 packet;
	int joytype = 0;
	int slot;

	/* Get a packet and check for validity */

	flags &= IO_RESET | IO_RETRY;
	flags = multiport_io(grip->gameport, flags, 0, &packet);
	grip->reads++;

	if (packet & PACKET_MP_DONE)
		flags |= IO_DONE;

	if (flags && !(flags & IO_GOT_PACKET)) {
		grip->bads++;
		return flags;
	}

	/* Ignore non-gamepad packets, e.g. multiport hardware version */

	slot = ((packet >> 21) & 0xf) - 1;
	if ((slot < 0) || (slot > 3))
		return flags;

	port = grip->port[slot];

	/*
	 * Handle "reset" packets, which occur at startup, and when gamepads
	 * are removed or plugged in.  May contain configuration of a new gamepad.
	 */

	joytype = (packet >> 16) & 0x1f;
	if (!joytype) {

		if (port->registered) {
			printk(KERN_INFO "grip_mp: removing %s, slot %d\n",
			       grip_name[port->mode], slot);
			input_unregister_device(port->dev);
			port->registered = 0;
		}
		dbg("Reset: grip multiport slot %d\n", slot);
		port->mode = GRIP_MODE_RESET;
		flags |= IO_SLOT_CHANGE;
		return flags;
	}

	/* Interpret a grip pad packet */

	if (joytype == 0x1f) {

		int dir = (packet >> 8) & 0xf;          /* eight way directional value */
		port->buttons = (~packet) & 0xff;
		port->yaxes = ((axis_map[dir] >> 2) & 3) - 1;
		port->xaxes = (axis_map[dir] & 3) - 1;
		port->dirty = 1;

		if (port->mode == GRIP_MODE_RESET)
			flags |= IO_SLOT_CHANGE;

		port->mode = GRIP_MODE_GP;

		if (!port->registered) {
			dbg("New Grip pad in multiport slot %d.\n", slot);
			if (register_slot(slot, grip)) {
				port->mode = GRIP_MODE_RESET;
				port->dirty = 0;
			}
		}
		return flags;
	}

	/* Handle non-grip device codes.  For now, just print diagnostics. */

	{
		static int strange_code = 0;
		if (strange_code != joytype) {
			printk(KERN_INFO "Possible non-grip pad/joystick detected.\n");
			printk(KERN_INFO "Got joy type 0x%x and packet 0x%x.\n", joytype, packet);
			strange_code = joytype;
		}
	}
	return flags;
}

/*
 * Returns true if all multiport slot states appear valid.
 */

static int slots_valid(struct grip_mp *grip)
{
	int flags, slot, invalid = 0, active = 0;

	flags = get_and_decode_packet(grip, 0);
	if (!(flags & IO_GOT_PACKET))
		return 0;

	for (slot = 0; slot < 4; slot++) {
		if (grip->port[slot]->mode == GRIP_MODE_RESET)
			invalid = 1;
		if (grip->port[slot]->mode != GRIP_MODE_NONE)
			active = 1;
	}

	/* Return true if no active slot but multiport sent all its data */
	if (!active)
		return (flags & IO_DONE) ? 1 : 0;

	/* Return false if invalid device code received */
	return invalid ? 0 : 1;
}

/*
 * Returns whether the multiport was placed into digital mode and
 * able to communicate its state successfully.
 */

static int multiport_init(struct grip_mp *grip)
{
	int dig_mode, initialized = 0, tries = 0;
	u32 packet;

	dig_mode = dig_mode_start(grip->gameport, &packet);
	while (!dig_mode && tries < 4) {
		dig_mode = dig_mode_start(grip->gameport, &packet);
		tries++;
	}

	if (dig_mode)
		dbg("multiport_init(): digital mode activated.\n");
	else {
		dbg("multiport_init(): unable to activate digital mode.\n");
		return 0;
	}

	/* Get packets, store multiport state, and check state's validity */
	for (tries = 0; tries < 4096; tries++) {
		if (slots_valid(grip)) {
			initialized = 1;
			break;
		}
	}
	dbg("multiport_init(): initialized == %d\n", initialized);
	return initialized;
}

/*
 * Reports joystick state to the linux input layer.
 */

static void report_slot(struct grip_mp *grip, int slot)
{
	struct grip_port *port = grip->port[slot];
	int i;

	/* Store button states with linux input driver */

	for (i = 0; i < 8; i++)
		input_report_key(port->dev, grip_btn_gp[i], (port->buttons >> i) & 1);

	/* Store axis states with linux driver */

	input_report_abs(port->dev, ABS_X, port->xaxes);
	input_report_abs(port->dev, ABS_Y, port->yaxes);

	/* Tell the receiver of the events to process them */

	input_sync(port->dev);

	port->dirty = 0;
}

/*
 * Get the multiport state.
 */

static void grip_poll(struct gameport *gameport)
{
	struct grip_mp *grip = gameport_get_drvdata(gameport);
	int i, npkts, flags;

	for (npkts = 0; npkts < 4; npkts++) {
		flags = IO_RETRY;
		for (i = 0; i < 32; i++) {
			flags = get_and_decode_packet(grip, flags);
			if ((flags & IO_GOT_PACKET) || !(flags & IO_RETRY))
				break;
		}
		if (flags & IO_DONE)
			break;
	}

	for (i = 0; i < 4; i++)
		if (grip->port[i]->dirty)
			report_slot(grip, i);
}

/*
 * Called when a joystick device file is opened
 */

static int grip_open(struct input_dev *dev)
{
	struct grip_mp *grip = input_get_drvdata(dev);

	gameport_start_polling(grip->gameport);
	return 0;
}

/*
 * Called when a joystick device file is closed
 */

static void grip_close(struct input_dev *dev)
{
	struct grip_mp *grip = input_get_drvdata(dev);

	gameport_stop_polling(grip->gameport);
}

/*
 * Tell the linux input layer about a newly plugged-in gamepad.
 */

static int register_slot(int slot, struct grip_mp *grip)
{
	struct grip_port *port = grip->port[slot];
	struct input_dev *input_dev;
	int j, t;
	int err;

	port->dev = input_dev = input_allocate_device();
	if (!input_dev)
		return -ENOMEM;

	input_dev->name = grip_name[port->mode];
	input_dev->id.bustype = BUS_GAMEPORT;
	input_dev->id.vendor = GAMEPORT_ID_VENDOR_GRAVIS;
	input_dev->id.product = 0x0100 + port->mode;
	input_dev->id.version = 0x0100;
	input_dev->dev.parent = &grip->gameport->dev;

	input_set_drvdata(input_dev, grip);

	input_dev->open = grip_open;
	input_dev->close = grip_close;

	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);

	for (j = 0; (t = grip_abs[port->mode][j]) >= 0; j++)
		input_set_abs_params(input_dev, t, -1, 1, 0, 0);

	for (j = 0; (t = grip_btn[port->mode][j]) >= 0; j++)
		if (t > 0)
			set_bit(t, input_dev->keybit);

	err = input_register_device(port->dev);
	if (err) {
		input_free_device(port->dev);
		return err;
	}

	port->registered = 1;

	if (port->dirty)	            /* report initial state, if any */
		report_slot(grip, slot);

	return 0;
}

static int grip_connect(struct gameport *gameport, struct gameport_driver *drv)
{
	struct grip_mp *grip;
	int err;

	if (!(grip = kzalloc(sizeof(struct grip_mp), GFP_KERNEL)))
		return -ENOMEM;

	grip->gameport = gameport;

	gameport_set_drvdata(gameport, grip);

	err = gameport_open(gameport, drv, GAMEPORT_MODE_RAW);
	if (err)
		goto fail1;

	gameport_set_poll_handler(gameport, grip_poll);
	gameport_set_poll_interval(gameport, 20);

	if (!multiport_init(grip)) {
		err = -ENODEV;
		goto fail2;
	}

	if (!grip->port[0]->mode && !grip->port[1]->mode && !grip->port[2]->mode && !grip->port[3]->mode) {
		/* nothing plugged in */
		err = -ENODEV;
		goto fail2;
	}

	return 0;

fail2:	gameport_close(gameport);
fail1:	gameport_set_drvdata(gameport, NULL);
	kfree(grip);
	return err;
}

static void grip_disconnect(struct gameport *gameport)
{
	struct grip_mp *grip = gameport_get_drvdata(gameport);
	int i;

	for (i = 0; i < 4; i++)
		if (grip->port[i]->registered)
			input_unregister_device(grip->port[i]->dev);
	gameport_close(gameport);
	gameport_set_drvdata(gameport, NULL);
	kfree(grip);
}

static struct gameport_driver grip_drv = {
	.driver		= {
		.name	= "grip_mp",
	},
	.description	= DRIVER_DESC,
	.connect	= grip_connect,
	.disconnect	= grip_disconnect,
};

module_gameport_driver(grip_drv);