Bootlin logo

Elixir Cross Referencer

   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
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
/*****************************************************************************
*
* Filename:      mcs7780.c
* Version:       0.4-alpha
* Description:   Irda MosChip USB Dongle Driver
* Authors:       Lukasz Stelmach <stlman@poczta.fm>
* 		 Brian Pugh <bpugh@cs.pdx.edu>
*		 Judy Fischbach <jfisch@cs.pdx.edu>
*
*       Based on stir4200 driver, but some things done differently.
*       Based on earlier driver by Paul Stewart <stewart@parc.com>
*
*       Copyright (C) 2000, Roman Weissgaerber <weissg@vienna.at>
*       Copyright (C) 2001, Dag Brattli <dag@brattli.net>
*       Copyright (C) 2001, Jean Tourrilhes <jt@hpl.hp.com>
*       Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org>
*       Copyright (C) 2005, Lukasz Stelmach <stlman@poczta.fm>
*       Copyright (C) 2005, Brian Pugh <bpugh@cs.pdx.edu>
*       Copyright (C) 2005, Judy Fischbach <jfisch@cs.pdx.edu>
*
*       This program is free software; you can redistribute it and/or modify
*       it under the terms of the GNU General Public License as published by
*       the Free Software Foundation; either version 2 of the License, or
*       (at your option) any later version.
*
*       This program is distributed in the hope that it will be useful,
*       but WITHOUT ANY WARRANTY; without even the implied warranty of
*       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
*       GNU General Public License for more details.
*
*       You should have received a copy of the GNU General Public License
*       along with this program; if not, write to the Free Software
*       Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*****************************************************************************/

/*
 * MCS7780 is a simple USB to IrDA bridge by MosChip. It is neither
 * compatibile with irda-usb nor with stir4200. Although it is quite
 * similar to the later as far as general idea of operation is concerned.
 * That is it requires the software to do all the framing job at SIR speeds.
 * The hardware does take care of the framing at MIR and FIR speeds.
 * It supports all speeds from 2400 through 4Mbps
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/kref.h>
#include <linux/usb.h>
#include <linux/device.h>
#include <linux/crc32.h>

#include <asm/unaligned.h>
#include <asm/byteorder.h>
#include <asm/uaccess.h>

#include <net/irda/irda.h>
#include <net/irda/wrapper.h>
#include <net/irda/crc.h>

#include "mcs7780.h"

#define MCS_VENDOR_ID 0x9710
#define MCS_PRODUCT_ID 0x7780

static struct usb_device_id mcs_table[] = {
	/* MosChip Corp.,  MCS7780 FIR-USB Adapter */
	{USB_DEVICE(MCS_VENDOR_ID, MCS_PRODUCT_ID)},
	{},
};

MODULE_AUTHOR("Brian Pugh <bpugh@cs.pdx.edu>");
MODULE_DESCRIPTION("IrDA-USB Dongle Driver for MosChip MCS7780");
MODULE_VERSION("0.3alpha");
MODULE_LICENSE("GPL");

MODULE_DEVICE_TABLE(usb, mcs_table);

static int qos_mtt_bits = 0x07 /* > 1ms */ ;
module_param(qos_mtt_bits, int, 0);
MODULE_PARM_DESC(qos_mtt_bits, "Minimum Turn Time");

static int receive_mode = 0x1;
module_param(receive_mode, int, 0);
MODULE_PARM_DESC(receive_mode,
		 "Receive mode of the device (1:fast, 0:slow, default:1)");

static int sir_tweak = 1;
module_param(sir_tweak, int, 0444);
MODULE_PARM_DESC(sir_tweak,
		 "Default pulse width (1:1.6us, 0:3/16 bit, default:1).");

static int transceiver_type = MCS_TSC_VISHAY;
module_param(transceiver_type, int, 0444);
MODULE_PARM_DESC(transceiver_type, "IR transceiver type, see mcs7780.h.");

static struct usb_driver mcs_driver = {
	.name = "mcs7780",
	.probe = mcs_probe,
	.disconnect = mcs_disconnect,
	.id_table = mcs_table,
};

/* speed flag selection by direct addressing.
addr = (speed >> 8) & 0x0f

0x1   57600	 0x2  115200	 0x4 1152000	 0x5    9600
0x6   38400	 0x9    2400	 0xa  576000	 0xb   19200

4Mbps (or 2400) must be checked separately. Since it also has
to be programmed in a different manner that is not a big problem.
*/
static __u16 mcs_speed_set[16] = { 0,
	MCS_SPEED_57600,
	MCS_SPEED_115200,
	0,
	MCS_SPEED_1152000,
	MCS_SPEED_9600,
	MCS_SPEED_38400,
	0, 0,
	MCS_SPEED_2400,
	MCS_SPEED_576000,
	MCS_SPEED_19200,
	0, 0, 0,
};

/* Set given 16 bit register with a 16 bit value. Send control message
 * to set dongle register. */
static int mcs_set_reg(struct mcs_cb *mcs, __u16 reg, __u16 val)
{
	struct usb_device *dev = mcs->usbdev;
	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0), MCS_WRREQ,
			       MCS_WR_RTYPE, val, reg, NULL, 0,
			       msecs_to_jiffies(MCS_CTRL_TIMEOUT));
}

/* Get 16 bit register value. Send contol message to read dongle register. */
static int mcs_get_reg(struct mcs_cb *mcs, __u16 reg, __u16 * val)
{
	struct usb_device *dev = mcs->usbdev;
	int ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), MCS_RDREQ,
				  MCS_RD_RTYPE, 0, reg, val, 2,
				  msecs_to_jiffies(MCS_CTRL_TIMEOUT));

	return ret;
}

/* Setup a communication between mcs7780 and TFDU chips.  It is described
 * in more detail in the data sheet.  The setup sequence puts the the
 * vishay tranceiver into high speed mode.  It will also receive SIR speed
 * packets but at reduced sensitivity.
 */

/* 0: OK 1:ERROR */
static inline int mcs_setup_transceiver_vishay(struct mcs_cb *mcs)
{
	int ret = 0;
	__u16 rval;

	/* mcs_get_reg should read exactly two bytes from the dongle */
	ret = mcs_get_reg(mcs, MCS_XCVR_REG, &rval);
	if (unlikely(ret != 2)) {
		ret = -EIO;
		goto error;
	}

	/* The MCS_XCVR_CONF bit puts the transceiver into configuration
	 * mode.  The MCS_MODE0 bit must start out high (1) and then
	 * transition to low and the MCS_STFIR and MCS_MODE1 bits must
	 * be low.
	 */
	rval |= (MCS_MODE0 | MCS_XCVR_CONF);
	rval &= ~MCS_STFIR;
	rval &= ~MCS_MODE1;
	ret = mcs_set_reg(mcs, MCS_XCVR_REG, rval);
	if (unlikely(ret))
		goto error;

	rval &= ~MCS_MODE0;
	ret = mcs_set_reg(mcs, MCS_XCVR_REG, rval);
	if (unlikely(ret))
		goto error;

	rval &= ~MCS_XCVR_CONF;
	ret = mcs_set_reg(mcs, MCS_XCVR_REG, rval);
	if (unlikely(ret))
		goto error;

	ret = 0;
	error:
		return ret;
}

/* Setup a communication between mcs7780 and agilent chip. */
static inline int mcs_setup_transceiver_agilent(struct mcs_cb *mcs)
{
	IRDA_WARNING("This transceiver type is not supported yet.\n");
	return 1;
}

/* Setup a communication between mcs7780 and sharp chip. */
static inline int mcs_setup_transceiver_sharp(struct mcs_cb *mcs)
{
	IRDA_WARNING("This transceiver type is not supported yet.\n");
	return 1;
}

/* Common setup for all transceivers */
static inline int mcs_setup_transceiver(struct mcs_cb *mcs)
{
	int ret = 0;
	__u16 rval;
	char *msg;

	msg = "Basic transceiver setup error.";

	/* read value of MODE Register, set the DRIVER and RESET bits
	* and write value back out to MODE Register
	*/
	ret = mcs_get_reg(mcs, MCS_MODE_REG, &rval);
	if(unlikely(ret != 2))
		goto error;
	rval |= MCS_DRIVER;	/* put the mcs7780 into configuration mode. */
	ret = mcs_set_reg(mcs, MCS_MODE_REG, rval);
	if(unlikely(ret))
		goto error;

	rval = 0;		/* set min pulse width to 0 initially. */
	ret = mcs_set_reg(mcs, MCS_MINRXPW_REG, rval);
	if(unlikely(ret))
		goto error;

	ret = mcs_get_reg(mcs, MCS_MODE_REG, &rval);
	if(unlikely(ret != 2))
		goto error;

	rval &= ~MCS_FIR;	/* turn off fir mode. */
	if(mcs->sir_tweak)
		rval |= MCS_SIR16US;	/* 1.6us pulse width */
	else
		rval &= ~MCS_SIR16US;	/* 3/16 bit time pulse width */

	/* make sure ask mode and back to back packets are off. */
	rval &= ~(MCS_BBTG | MCS_ASK);

	rval &= ~MCS_SPEED_MASK;
	rval |= MCS_SPEED_9600;		/* make sure initial speed is 9600. */
	mcs->speed = 9600;
	mcs->new_speed = 0;		/* new_speed is set to 0 */
	rval &= ~MCS_PLLPWDN;		/* disable power down. */

	/* make sure device determines direction and that the auto send sip
	 * pulse are on.
	 */
	rval |= MCS_DTD | MCS_SIPEN;

	ret = mcs_set_reg(mcs, MCS_MODE_REG, rval);
	if(unlikely(ret))
		goto error;

	msg = "transceiver model specific setup error.";
	switch (mcs->transceiver_type) {
	case MCS_TSC_VISHAY:
		ret = mcs_setup_transceiver_vishay(mcs);
		break;

	case MCS_TSC_SHARP:
		ret = mcs_setup_transceiver_sharp(mcs);
		break;

	case MCS_TSC_AGILENT:
		ret = mcs_setup_transceiver_agilent(mcs);
		break;

	default:
		IRDA_WARNING("Unknown transceiver type: %d\n",
			     mcs->transceiver_type);
		ret = 1;
	}
	if (unlikely(ret))
		goto error;

	/* If transceiver is not SHARP, then if receive mode set
	* on the RXFAST bit in the XCVR Register otherwise unset it
	*/
	if (mcs->transceiver_type != MCS_TSC_SHARP) {

		ret = mcs_get_reg(mcs, MCS_XCVR_REG, &rval);
		if (unlikely(ret != 2))
			goto error;
		if (mcs->receive_mode)
			rval |= MCS_RXFAST;
		else
			rval &= ~MCS_RXFAST;
		ret = mcs_set_reg(mcs, MCS_XCVR_REG, rval);
		if (unlikely(ret))
			goto error;
	}

	msg = "transceiver reset.";

	ret = mcs_get_reg(mcs, MCS_MODE_REG, &rval);
	if (unlikely(ret != 2))
		goto error;

	/* reset the mcs7780 so all changes take effect. */
	rval &= ~MCS_RESET;
	ret = mcs_set_reg(mcs, MCS_MODE_REG, rval);
	if (unlikely(ret))
		goto error;
	else
		return ret;

error:
	IRDA_ERROR("%s\n", msg);
	return ret;
}

/* Wraps the data in format for SIR */
static inline int mcs_wrap_sir_skb(struct sk_buff *skb, __u8 * buf)
{
	int wraplen;

	/* 2: full frame length, including "the length" */
	wraplen = async_wrap_skb(skb, buf + 2, 4094);

	wraplen += 2;
	buf[0] = wraplen & 0xff;
	buf[1] = (wraplen >> 8) & 0xff;

	return wraplen;
}

/* Wraps the data in format for FIR */
static unsigned mcs_wrap_fir_skb(const struct sk_buff *skb, __u8 *buf)
{
	unsigned int len = 0;
	__u32 fcs = ~(crc32_le(~0, skb->data, skb->len));

	/* add 2 bytes for length value and 4 bytes for fcs. */
	len = skb->len + 6;

	/* The mcs7780 requires that the first two bytes are the packet
	 * length in little endian order.  Note: the length value includes
	 * the two bytes for the length value itself.
	 */
	buf[0] = len & 0xff;
	buf[1] = (len >> 8) & 0xff;
	/* copy the data into the tx buffer. */
	skb_copy_from_linear_data(skb, buf + 2, skb->len);
	/* put the fcs in the last four bytes in little endian order. */
	buf[len - 4] = fcs & 0xff;
	buf[len - 3] = (fcs >> 8) & 0xff;
	buf[len - 2] = (fcs >> 16) & 0xff;
	buf[len - 1] = (fcs >> 24) & 0xff;

	return len;
}

/* Wraps the data in format for MIR */
static unsigned mcs_wrap_mir_skb(const struct sk_buff *skb, __u8 *buf)
{
	__u16 fcs = 0;
	int len = skb->len + 4;

	fcs = ~(irda_calc_crc16(~fcs, skb->data, skb->len));
	/* put the total packet length in first.  Note: packet length
	 * value includes the two bytes that hold the packet length
	 * itself.
	 */
	buf[0] = len & 0xff;
	buf[1] = (len >> 8) & 0xff;
	/* copy the data */
	skb_copy_from_linear_data(skb, buf + 2, skb->len);
	/* put the fcs in last two bytes in little endian order. */
	buf[len - 2] = fcs & 0xff;
	buf[len - 1] = (fcs >> 8) & 0xff;

	return len;
}

/* Unwrap received packets at MIR speed.  A 16 bit crc_ccitt checksum is
 * used for the fcs.  When performed over the entire packet the result
 * should be GOOD_FCS = 0xf0b8.  Hands the unwrapped data off to the IrDA
 * layer via a sk_buff.
 */
static void mcs_unwrap_mir(struct mcs_cb *mcs, __u8 *buf, int len)
{
	__u16 fcs;
	int new_len;
	struct sk_buff *skb;

	/* Assume that the frames are going to fill a single packet
	 * rather than span multiple packets.
	 */

	new_len = len - 2;
	if(unlikely(new_len <= 0)) {
		IRDA_ERROR("%s short frame length %d\n",
			     mcs->netdev->name, new_len);
		++mcs->stats.rx_errors;
		++mcs->stats.rx_length_errors;
		return;
	}
	fcs = 0;
	fcs = irda_calc_crc16(~fcs, buf, len);

	if(fcs != GOOD_FCS) {
		IRDA_ERROR("crc error calc 0x%x len %d\n",
			   fcs, new_len);
		mcs->stats.rx_errors++;
		mcs->stats.rx_crc_errors++;
		return;
	}

	skb = dev_alloc_skb(new_len + 1);
	if(unlikely(!skb)) {
		++mcs->stats.rx_dropped;
		return;
	}

	skb_reserve(skb, 1);
	skb_copy_to_linear_data(skb, buf, new_len);
	skb_put(skb, new_len);
	skb_reset_mac_header(skb);
	skb->protocol = htons(ETH_P_IRDA);
	skb->dev = mcs->netdev;

	netif_rx(skb);

	mcs->stats.rx_packets++;
	mcs->stats.rx_bytes += new_len;

	return;
}

/* Unwrap received packets at FIR speed.  A 32 bit crc_ccitt checksum is
 * used for the fcs.  Hands the unwrapped data off to the IrDA
 * layer via a sk_buff.
 */
static void mcs_unwrap_fir(struct mcs_cb *mcs, __u8 *buf, int len)
{
	__u32 fcs;
	int new_len;
	struct sk_buff *skb;

	/* Assume that the frames are going to fill a single packet
	 * rather than span multiple packets.  This is most likely a false
	 * assumption.
	 */

	new_len = len - 4;
	if(unlikely(new_len <= 0)) {
		IRDA_ERROR("%s short frame length %d\n",
			   mcs->netdev->name, new_len);
		++mcs->stats.rx_errors;
		++mcs->stats.rx_length_errors;
		return;
	}

	fcs = ~(crc32_le(~0, buf, new_len));
	if(fcs != get_unaligned_le32(buf + new_len)) {
		IRDA_ERROR("crc error calc 0x%x len %d\n", fcs, new_len);
		mcs->stats.rx_errors++;
		mcs->stats.rx_crc_errors++;
		return;
	}

	skb = dev_alloc_skb(new_len + 1);
	if(unlikely(!skb)) {
		++mcs->stats.rx_dropped;
		return;
	}

	skb_reserve(skb, 1);
	skb_copy_to_linear_data(skb, buf, new_len);
	skb_put(skb, new_len);
	skb_reset_mac_header(skb);
	skb->protocol = htons(ETH_P_IRDA);
	skb->dev = mcs->netdev;

	netif_rx(skb);

	mcs->stats.rx_packets++;
	mcs->stats.rx_bytes += new_len;

	return;
}


/* Allocates urbs for both receive and transmit.
 * If alloc fails return error code 0 (fail) otherwise
 * return error code 1 (success).
 */
static inline int mcs_setup_urbs(struct mcs_cb *mcs)
{
	mcs->rx_urb = NULL;

	mcs->tx_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!mcs->tx_urb)
		return 0;

	mcs->rx_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!mcs->rx_urb)
		return 0;

	return 1;
}

/* Sets up state to be initially outside frame, gets receive urb,
 * sets status to successful and then submits the urb to start
 * receiving the data.
 */
static inline int mcs_receive_start(struct mcs_cb *mcs)
{
	mcs->rx_buff.in_frame = FALSE;
	mcs->rx_buff.state = OUTSIDE_FRAME;

	usb_fill_bulk_urb(mcs->rx_urb, mcs->usbdev,
			  usb_rcvbulkpipe(mcs->usbdev, mcs->ep_in),
			  mcs->in_buf, 4096, mcs_receive_irq, mcs);

	mcs->rx_urb->status = 0;
	return usb_submit_urb(mcs->rx_urb, GFP_KERNEL);
}

/* Finds the in and out endpoints for the mcs control block */
static inline int mcs_find_endpoints(struct mcs_cb *mcs,
				     struct usb_host_endpoint *ep, int epnum)
{
	int i;
	int ret = 0;

	/* If no place to store the endpoints just return */
	if (!ep)
		return ret;

	/* cycle through all endpoints, find the first two that are DIR_IN */
	for (i = 0; i < epnum; i++) {
		if (ep[i].desc.bEndpointAddress & USB_DIR_IN)
			mcs->ep_in = ep[i].desc.bEndpointAddress;
		else
			mcs->ep_out = ep[i].desc.bEndpointAddress;

		/* MosChip says that the chip has only two bulk
		 * endpoints. Find one for each direction and move on.
		 */
		if ((mcs->ep_in != 0) && (mcs->ep_out != 0)) {
			ret = 1;
			break;
		}
	}

	return ret;
}

static void mcs_speed_work(struct work_struct *work)
{
	struct mcs_cb *mcs = container_of(work, struct mcs_cb, work);
	struct net_device *netdev = mcs->netdev;

	mcs_speed_change(mcs);
	netif_wake_queue(netdev);
}

/* Function to change the speed of the mcs7780.  Fully supports SIR,
 * MIR, and FIR speeds.
 */
static int mcs_speed_change(struct mcs_cb *mcs)
{
	int ret = 0;
	int rst = 0;
	int cnt = 0;
	__u16 nspeed;
	__u16 rval;

	nspeed = mcs_speed_set[(mcs->new_speed >> 8) & 0x0f];

	do {
		mcs_get_reg(mcs, MCS_RESV_REG, &rval);
	} while(cnt++ < 100 && (rval & MCS_IRINTX));

	if(cnt >= 100) {
		IRDA_ERROR("unable to change speed\n");
		ret = -EIO;
		goto error;
	}

	mcs_get_reg(mcs, MCS_MODE_REG, &rval);

	/* MINRXPW values recomended by MosChip */
	if (mcs->new_speed <= 115200) {
		rval &= ~MCS_FIR;

		if ((rst = (mcs->speed > 115200)))
			mcs_set_reg(mcs, MCS_MINRXPW_REG, 0);

	} else if (mcs->new_speed <= 1152000) {
		rval &= ~MCS_FIR;

		if ((rst = !(mcs->speed == 576000 || mcs->speed == 1152000)))
			mcs_set_reg(mcs, MCS_MINRXPW_REG, 5);

	} else {
		rval |= MCS_FIR;

		if ((rst = (mcs->speed != 4000000)))
			mcs_set_reg(mcs, MCS_MINRXPW_REG, 5);

	}

	rval &= ~MCS_SPEED_MASK;
	rval |= nspeed;

	ret = mcs_set_reg(mcs, MCS_MODE_REG, rval);
	if (unlikely(ret))
		goto error;

	if (rst)
		switch (mcs->transceiver_type) {
		case MCS_TSC_VISHAY:
			ret = mcs_setup_transceiver_vishay(mcs);
			break;

		case MCS_TSC_SHARP:
			ret = mcs_setup_transceiver_sharp(mcs);
			break;

		case MCS_TSC_AGILENT:
			ret = mcs_setup_transceiver_agilent(mcs);
			break;

		default:
			ret = 1;
			IRDA_WARNING("Unknown transceiver type: %d\n",
				     mcs->transceiver_type);
		}
	if (unlikely(ret))
		goto error;

	mcs_get_reg(mcs, MCS_MODE_REG, &rval);
	rval &= ~MCS_RESET;
	ret = mcs_set_reg(mcs, MCS_MODE_REG, rval);

	mcs->speed = mcs->new_speed;
	error:
		mcs->new_speed = 0;
		return ret;
}

/* Ioctl calls not supported at this time.  Can be an area of future work. */
static int mcs_net_ioctl(struct net_device *netdev, struct ifreq *rq, int cmd)
{
	/* struct if_irda_req *irq = (struct if_irda_req *)rq; */
	/* struct mcs_cb *mcs = netdev_priv(netdev); */
	int ret = 0;

	switch (cmd) {
	default:
		ret = -EOPNOTSUPP;
	}

	return ret;
}

/* Network device is taken down, done by "ifconfig irda0 down" */
static int mcs_net_close(struct net_device *netdev)
{
	int ret = 0;
	struct mcs_cb *mcs = netdev_priv(netdev);

	/* Stop transmit processing */
	netif_stop_queue(netdev);

	kfree_skb(mcs->rx_buff.skb);

	/* kill and free the receive and transmit URBs */
	usb_kill_urb(mcs->rx_urb);
	usb_free_urb(mcs->rx_urb);
	usb_kill_urb(mcs->tx_urb);
	usb_free_urb(mcs->tx_urb);

	/* Stop and remove instance of IrLAP */
	if (mcs->irlap)
		irlap_close(mcs->irlap);

	mcs->irlap = NULL;
	return ret;
}

/* Network device is taken up, done by "ifconfig irda0 up" */
static int mcs_net_open(struct net_device *netdev)
{
	struct mcs_cb *mcs = netdev_priv(netdev);
	char hwname[16];
	int ret = 0;

	ret = usb_clear_halt(mcs->usbdev,
			     usb_sndbulkpipe(mcs->usbdev, mcs->ep_in));
	if (ret)
		goto error1;
	ret = usb_clear_halt(mcs->usbdev,
			     usb_rcvbulkpipe(mcs->usbdev, mcs->ep_out));
	if (ret)
		goto error1;

	ret = mcs_setup_transceiver(mcs);
	if (ret)
		goto error1;

	ret = -ENOMEM;

	/* Initialize for SIR/FIR to copy data directly into skb.  */
	mcs->receiving = 0;
	mcs->rx_buff.truesize = IRDA_SKB_MAX_MTU;
	mcs->rx_buff.skb = dev_alloc_skb(IRDA_SKB_MAX_MTU);
	if (!mcs->rx_buff.skb)
		goto error1;

	skb_reserve(mcs->rx_buff.skb, 1);
	mcs->rx_buff.head = mcs->rx_buff.skb->data;
	do_gettimeofday(&mcs->rx_time);

	/*
	 * Now that everything should be initialized properly,
	 * Open new IrLAP layer instance to take care of us...
	 * Note : will send immediately a speed change...
	 */
	sprintf(hwname, "usb#%d", mcs->usbdev->devnum);
	mcs->irlap = irlap_open(netdev, &mcs->qos, hwname);
	if (!mcs->irlap) {
		IRDA_ERROR("mcs7780: irlap_open failed\n");
		goto error2;
	}

	if (!mcs_setup_urbs(mcs))
	goto error3;

	ret = mcs_receive_start(mcs);
	if (ret)
		goto error3;

	netif_start_queue(netdev);
	return 0;

	error3:
		irlap_close(mcs->irlap);
	error2:
		kfree_skb(mcs->rx_buff.skb);
	error1:
		return ret;
}


/* Get device stats for /proc/net/dev and ifconfig */
static struct net_device_stats *mcs_net_get_stats(struct net_device *netdev)
{
	struct mcs_cb *mcs = netdev_priv(netdev);
	return &mcs->stats;
}

/* Receive callback function.  */
static void mcs_receive_irq(struct urb *urb)
{
	__u8 *bytes;
	struct mcs_cb *mcs = urb->context;
	int i;
	int ret;

	if (!netif_running(mcs->netdev))
		return;

	if (urb->status)
		return;

	if (urb->actual_length > 0) {
		bytes = urb->transfer_buffer;

		/* MCS returns frames without BOF and EOF
		 * I assume it returns whole frames.
		 */
		/* SIR speed */
		if(mcs->speed < 576000) {
			async_unwrap_char(mcs->netdev, &mcs->stats,
				  &mcs->rx_buff, 0xc0);

			for (i = 0; i < urb->actual_length; i++)
				async_unwrap_char(mcs->netdev, &mcs->stats,
					  &mcs->rx_buff, bytes[i]);

			async_unwrap_char(mcs->netdev, &mcs->stats,
				  &mcs->rx_buff, 0xc1);
		}
		/* MIR speed */
		else if(mcs->speed == 576000 || mcs->speed == 1152000) {
			mcs_unwrap_mir(mcs, urb->transfer_buffer,
				urb->actual_length);
		}
		/* FIR speed */
		else {
			mcs_unwrap_fir(mcs, urb->transfer_buffer,
				urb->actual_length);
		}
		mcs->netdev->last_rx = jiffies;
		do_gettimeofday(&mcs->rx_time);
	}

	ret = usb_submit_urb(urb, GFP_ATOMIC);
}

/* Transmit callback funtion.  */
static void mcs_send_irq(struct urb *urb)
{
	struct mcs_cb *mcs = urb->context;
	struct net_device *ndev = mcs->netdev;

	if (unlikely(mcs->new_speed))
		schedule_work(&mcs->work);
	else
		netif_wake_queue(ndev);
}

/* Transmit callback funtion.  */
static int mcs_hard_xmit(struct sk_buff *skb, struct net_device *ndev)
{
	unsigned long flags;
	struct mcs_cb *mcs;
	int wraplen;
	int ret = 0;


	if (skb == NULL || ndev == NULL)
		return -EINVAL;

	netif_stop_queue(ndev);
	mcs = netdev_priv(ndev);

	spin_lock_irqsave(&mcs->lock, flags);

	mcs->new_speed = irda_get_next_speed(skb);
	if (likely(mcs->new_speed == mcs->speed))
		mcs->new_speed = 0;

	/* SIR speed */
	if(mcs->speed < 576000) {
		wraplen = mcs_wrap_sir_skb(skb, mcs->out_buf);
	}
	/* MIR speed */
	else if(mcs->speed == 576000 || mcs->speed == 1152000) {
		wraplen = mcs_wrap_mir_skb(skb, mcs->out_buf);
	}
	/* FIR speed */
	else {
		wraplen = mcs_wrap_fir_skb(skb, mcs->out_buf);
	}
	usb_fill_bulk_urb(mcs->tx_urb, mcs->usbdev,
			  usb_sndbulkpipe(mcs->usbdev, mcs->ep_out),
			  mcs->out_buf, wraplen, mcs_send_irq, mcs);

	if ((ret = usb_submit_urb(mcs->tx_urb, GFP_ATOMIC))) {
		IRDA_ERROR("failed tx_urb: %d\n", ret);
		switch (ret) {
		case -ENODEV:
		case -EPIPE:
			break;
		default:
			mcs->stats.tx_errors++;
			netif_start_queue(ndev);
		}
	} else {
		mcs->stats.tx_packets++;
		mcs->stats.tx_bytes += skb->len;
	}

	dev_kfree_skb(skb);
	spin_unlock_irqrestore(&mcs->lock, flags);
	return ret;
}

/*
 * This function is called by the USB subsystem for each new device in the
 * system.  Need to verify the device and if it is, then start handling it.
 */
static int mcs_probe(struct usb_interface *intf,
		     const struct usb_device_id *id)
{
	struct usb_device *udev = interface_to_usbdev(intf);
	struct net_device *ndev = NULL;
	struct mcs_cb *mcs;
	int ret = -ENOMEM;

	ndev = alloc_irdadev(sizeof(*mcs));
	if (!ndev)
		goto error1;

	IRDA_DEBUG(1, "MCS7780 USB-IrDA bridge found at %d.\n", udev->devnum);

	SET_NETDEV_DEV(ndev, &intf->dev);

	ret = usb_reset_configuration(udev);
	if (ret != 0) {
		IRDA_ERROR("mcs7780: usb reset configuration failed\n");
		goto error2;
	}

	mcs = netdev_priv(ndev);
	mcs->usbdev = udev;
	mcs->netdev = ndev;
	spin_lock_init(&mcs->lock);

	/* Initialize QoS for this device */
	irda_init_max_qos_capabilies(&mcs->qos);

	/* That's the Rx capability. */
	mcs->qos.baud_rate.bits &=
	    IR_2400 | IR_9600 | IR_19200 | IR_38400 | IR_57600 | IR_115200
		| IR_576000 | IR_1152000 | (IR_4000000 << 8);


	mcs->qos.min_turn_time.bits &= qos_mtt_bits;
	irda_qos_bits_to_value(&mcs->qos);

	/* Speed change work initialisation*/
	INIT_WORK(&mcs->work, mcs_speed_work);

	/* Override the network functions we need to use */
	ndev->hard_start_xmit = mcs_hard_xmit;
	ndev->open = mcs_net_open;
	ndev->stop = mcs_net_close;
	ndev->get_stats = mcs_net_get_stats;
	ndev->do_ioctl = mcs_net_ioctl;

	if (!intf->cur_altsetting)
		goto error2;

	ret = mcs_find_endpoints(mcs, intf->cur_altsetting->endpoint,
				 intf->cur_altsetting->desc.bNumEndpoints);
	if (!ret) {
		ret = -ENODEV;
		goto error2;
	}

	ret = register_netdev(ndev);
	if (ret != 0)
		goto error2;

	IRDA_DEBUG(1, "IrDA: Registered MosChip MCS7780 device as %s\n",
		   ndev->name);

	mcs->transceiver_type = transceiver_type;
	mcs->sir_tweak = sir_tweak;
	mcs->receive_mode = receive_mode;

	usb_set_intfdata(intf, mcs);
	return 0;

	error2:
		free_netdev(ndev);

	error1:
		return ret;
}

/* The current device is removed, the USB layer tells us to shut down. */
static void mcs_disconnect(struct usb_interface *intf)
{
	struct mcs_cb *mcs = usb_get_intfdata(intf);

	if (!mcs)
		return;

	flush_scheduled_work();

	unregister_netdev(mcs->netdev);
	free_netdev(mcs->netdev);

	usb_set_intfdata(intf, NULL);
	IRDA_DEBUG(0, "MCS7780 now disconnected.\n");
}

/* Module insertion */
static int __init mcs_init(void)
{
	int result;

	/* register this driver with the USB subsystem */
	result = usb_register(&mcs_driver);
	if (result)
		IRDA_ERROR("usb_register failed. Error number %d\n", result);

	return result;
}
module_init(mcs_init);

/* Module removal */
static void __exit mcs_exit(void)
{
	/* deregister this driver with the USB subsystem */
	usb_deregister(&mcs_driver);
}
module_exit(mcs_exit);