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
 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
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
/*****************************************************************************
*
* Filename:      stir4200.c
* Version:       0.4
* Description:   Irda SigmaTel USB Dongle
* Status:        Experimental
* Author:        Stephen Hemminger <shemminger@osdl.org>
*
*  	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>
*
*	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.
*
*	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.
*
*****************************************************************************/

/*
 * This dongle does no framing, and requires polling to receive the
 * data.  The STIr4200 has bulk in and out endpoints just like
 * usr-irda devices, but the data it sends and receives is raw; like
 * irtty, it needs to call the wrap and unwrap functions to add and
 * remove SOF/BOF and escape characters to/from the frame.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/usb.h>
#include <linux/crc32.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <net/irda/irda.h>
#include <net/irda/irda_device.h>
#include <net/irda/wrapper.h>
#include <net/irda/crc.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>

MODULE_AUTHOR("Stephen Hemminger <shemminger@linux-foundation.org>");
MODULE_DESCRIPTION("IrDA-USB Dongle Driver for SigmaTel STIr4200");
MODULE_LICENSE("GPL");

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

static int rx_sensitivity = 1;	/* FIR 0..4, SIR 0..6 */
module_param(rx_sensitivity, int, 0);
MODULE_PARM_DESC(rx_sensitivity, "Set Receiver sensitivity (0-6, 0 is most sensitive)");

static int tx_power = 0;	/* 0 = highest ... 3 = lowest */
module_param(tx_power, int, 0);
MODULE_PARM_DESC(tx_power, "Set Transmitter power (0-3, 0 is highest power)");

#define STIR_IRDA_HEADER  	4
#define CTRL_TIMEOUT		100	   /* milliseconds */
#define TRANSMIT_TIMEOUT	200	   /* milliseconds */
#define STIR_FIFO_SIZE		4096
#define FIFO_REGS_SIZE		3

enum FirChars {
	FIR_CE   = 0x7d,
	FIR_XBOF = 0x7f,
	FIR_EOF  = 0x7e,
};

enum StirRequests {
	REQ_WRITE_REG =		0x00,
	REQ_READ_REG =		0x01,
	REQ_READ_ROM =		0x02,
	REQ_WRITE_SINGLE =	0x03,
};

/* Register offsets */
enum StirRegs {
	REG_RSVD=0,
	REG_MODE,
	REG_PDCLK,
	REG_CTRL1,
	REG_CTRL2,
	REG_FIFOCTL,
	REG_FIFOLSB,
	REG_FIFOMSB,
	REG_DPLL,
	REG_IRDIG,
	REG_TEST=15,
};

enum StirModeMask {
	MODE_FIR = 0x80,
	MODE_SIR = 0x20,
	MODE_ASK = 0x10,
	MODE_FASTRX = 0x08,
	MODE_FFRSTEN = 0x04,
	MODE_NRESET = 0x02,
	MODE_2400 = 0x01,
};

enum StirPdclkMask {
	PDCLK_4000000 = 0x02,
	PDCLK_115200 = 0x09,
	PDCLK_57600 = 0x13,
	PDCLK_38400 = 0x1D,
	PDCLK_19200 = 0x3B,
	PDCLK_9600 = 0x77,
	PDCLK_2400 = 0xDF,
};

enum StirCtrl1Mask {
	CTRL1_SDMODE = 0x80,
	CTRL1_RXSLOW = 0x40,
	CTRL1_TXPWD = 0x10,
	CTRL1_RXPWD = 0x08,
	CTRL1_SRESET = 0x01,
};

enum StirCtrl2Mask {
	CTRL2_SPWIDTH = 0x08,
	CTRL2_REVID = 0x03,
};

enum StirFifoCtlMask {
	FIFOCTL_DIR = 0x10,
	FIFOCTL_CLR = 0x08,
	FIFOCTL_EMPTY = 0x04,
};

enum StirDiagMask {
	IRDIG_RXHIGH = 0x80,
	IRDIG_RXLOW = 0x40,
};

enum StirTestMask {
	TEST_PLLDOWN = 0x80,
	TEST_LOOPIR = 0x40,
	TEST_LOOPUSB = 0x20,
	TEST_TSTENA = 0x10,
	TEST_TSTOSC = 0x0F,
};

struct stir_cb {
        struct usb_device *usbdev;      /* init: probe_irda */
        struct net_device *netdev;      /* network layer */
        struct irlap_cb   *irlap;       /* The link layer we are binded to */

        struct qos_info   qos;
	unsigned 	  speed;	/* Current speed */

        struct task_struct *thread;     /* transmit thread */

	struct sk_buff	  *tx_pending;
	void		  *io_buf;	/* transmit/receive buffer */
	__u8		  *fifo_status;

	iobuff_t  	  rx_buff;	/* receive unwrap state machine */
	struct timeval	  rx_time;
	int		  receiving;
	struct urb	 *rx_urb;
};


/* These are the currently known USB ids */
static struct usb_device_id dongles[] = {
    /* SigmaTel, Inc,  STIr4200 IrDA/USB Bridge */
    { USB_DEVICE(0x066f, 0x4200) },
    { }
};

MODULE_DEVICE_TABLE(usb, dongles);

/* Send control message to set dongle register */
static int write_reg(struct stir_cb *stir, __u16 reg, __u8 value)
{
	struct usb_device *dev = stir->usbdev;

	pr_debug("%s: write reg %d = 0x%x\n",
		 stir->netdev->name, reg, value);
	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
			       REQ_WRITE_SINGLE,
			       USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_DEVICE,
			       value, reg, NULL, 0,
			       CTRL_TIMEOUT);
}

/* Send control message to read multiple registers */
static inline int read_reg(struct stir_cb *stir, __u16 reg,
		    __u8 *data, __u16 count)
{
	struct usb_device *dev = stir->usbdev;

	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
			       REQ_READ_REG,
			       USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
			       0, reg, data, count,
			       CTRL_TIMEOUT);
}

static inline int isfir(u32 speed)
{
	return (speed == 4000000);
}

/*
 * Prepare a FIR IrDA frame for transmission to the USB dongle.  The
 * FIR transmit frame is documented in the datasheet.  It consists of
 * a two byte 0x55 0xAA sequence, two little-endian length bytes, a
 * sequence of exactly 16 XBOF bytes of 0x7E, two BOF bytes of 0x7E,
 * then the data escaped as follows:
 *
 *    0x7D -> 0x7D 0x5D
 *    0x7E -> 0x7D 0x5E
 *    0x7F -> 0x7D 0x5F
 *
 * Then, 4 bytes of little endian (stuffed) FCS follow, then two
 * trailing EOF bytes of 0x7E.
 */
static inline __u8 *stuff_fir(__u8 *p, __u8 c)
{
	switch(c) {
	case 0x7d:
	case 0x7e:
	case 0x7f:
		*p++ = 0x7d;
		c ^= IRDA_TRANS;
		/* fall through */
	default:
		*p++ = c;
	}
	return p;
}

/* Take raw data in skb and put it wrapped into buf */
static unsigned wrap_fir_skb(const struct sk_buff *skb, __u8 *buf)
{
	__u8 *ptr = buf;
	__u32 fcs = ~(crc32_le(~0, skb->data, skb->len));
	__u16 wraplen;
	int i;

	/* Header */
	buf[0] = 0x55;
	buf[1] = 0xAA;

	ptr = buf + STIR_IRDA_HEADER;
	memset(ptr, 0x7f, 16);
	ptr += 16;

	/* BOF */
	*ptr++  = 0x7e;
	*ptr++  = 0x7e;

	/* Address / Control / Information */
	for (i = 0; i < skb->len; i++)
		ptr = stuff_fir(ptr, skb->data[i]);

	/* FCS */
	ptr = stuff_fir(ptr, fcs & 0xff);
	ptr = stuff_fir(ptr, (fcs >> 8) & 0xff);
	ptr = stuff_fir(ptr, (fcs >> 16) & 0xff);
	ptr = stuff_fir(ptr, (fcs >> 24) & 0xff);

	/* EOFs */
	*ptr++ = 0x7e;
	*ptr++ = 0x7e;

	/* Total length, minus the header */
	wraplen = (ptr - buf) - STIR_IRDA_HEADER;
	buf[2] = wraplen & 0xff;
	buf[3] = (wraplen >> 8) & 0xff;

	return wraplen + STIR_IRDA_HEADER;
}

static unsigned wrap_sir_skb(struct sk_buff *skb, __u8 *buf)
{
	__u16 wraplen;

	wraplen = async_wrap_skb(skb, buf + STIR_IRDA_HEADER,
				 STIR_FIFO_SIZE - STIR_IRDA_HEADER);
	buf[0] = 0x55;
	buf[1] = 0xAA;
	buf[2] = wraplen & 0xff;
	buf[3] = (wraplen >> 8) & 0xff;

	return wraplen + STIR_IRDA_HEADER;
}

/*
 * Frame is fully formed in the rx_buff so check crc
 * and pass up to irlap
 * setup for next receive
 */
static void fir_eof(struct stir_cb *stir)
{
	iobuff_t *rx_buff = &stir->rx_buff;
	int len = rx_buff->len - 4;
	struct sk_buff *skb, *nskb;
	__u32 fcs;

	if (unlikely(len <= 0)) {
		pr_debug("%s: short frame len %d\n",
			 stir->netdev->name, len);

		++stir->netdev->stats.rx_errors;
		++stir->netdev->stats.rx_length_errors;
		return;
	}

	fcs = ~(crc32_le(~0, rx_buff->data, len));
	if (fcs != get_unaligned_le32(rx_buff->data + len)) {
		pr_debug("crc error calc 0x%x len %d\n", fcs, len);
		stir->netdev->stats.rx_errors++;
		stir->netdev->stats.rx_crc_errors++;
		return;
	}

	/* if frame is short then just copy it */
	if (len < IRDA_RX_COPY_THRESHOLD) {
		nskb = dev_alloc_skb(len + 1);
		if (unlikely(!nskb)) {
			++stir->netdev->stats.rx_dropped;
			return;
		}
		skb_reserve(nskb, 1);
		skb = nskb;
		skb_copy_to_linear_data(nskb, rx_buff->data, len);
	} else {
		nskb = dev_alloc_skb(rx_buff->truesize);
		if (unlikely(!nskb)) {
			++stir->netdev->stats.rx_dropped;
			return;
		}
		skb_reserve(nskb, 1);
		skb = rx_buff->skb;
		rx_buff->skb = nskb;
		rx_buff->head = nskb->data;
	}

	skb_put(skb, len);

	skb_reset_mac_header(skb);
	skb->protocol = htons(ETH_P_IRDA);
	skb->dev = stir->netdev;

	netif_rx(skb);

	stir->netdev->stats.rx_packets++;
	stir->netdev->stats.rx_bytes += len;

	rx_buff->data = rx_buff->head;
	rx_buff->len = 0;
}

/* Unwrap FIR stuffed data and bump it to IrLAP */
static void stir_fir_chars(struct stir_cb *stir,
			    const __u8 *bytes, int len)
{
	iobuff_t *rx_buff = &stir->rx_buff;
	int	i;

	for (i = 0; i < len; i++) {
		__u8	byte = bytes[i];

		switch(rx_buff->state) {
		case OUTSIDE_FRAME:
			/* ignore garbage till start of frame */
			if (unlikely(byte != FIR_EOF))
				continue;
			/* Now receiving frame */
			rx_buff->state = BEGIN_FRAME;

			/* Time to initialize receive buffer */
			rx_buff->data = rx_buff->head;
			rx_buff->len = 0;
			continue;

		case LINK_ESCAPE:
			if (byte == FIR_EOF) {
				pr_debug("%s: got EOF after escape\n",
					 stir->netdev->name);
				goto frame_error;
			}
			rx_buff->state = INSIDE_FRAME;
			byte ^= IRDA_TRANS;
			break;

		case BEGIN_FRAME:
			/* ignore multiple BOF/EOF */
			if (byte == FIR_EOF)
				continue;
			rx_buff->state = INSIDE_FRAME;
			rx_buff->in_frame = TRUE;

			/* fall through */
		case INSIDE_FRAME:
			switch(byte) {
			case FIR_CE:
				rx_buff->state = LINK_ESCAPE;
				continue;
			case FIR_XBOF:
				/* 0x7f is not used in this framing */
				pr_debug("%s: got XBOF without escape\n",
					 stir->netdev->name);
				goto frame_error;
			case FIR_EOF:
				rx_buff->state = OUTSIDE_FRAME;
				rx_buff->in_frame = FALSE;
				fir_eof(stir);
				continue;
			}
			break;
		}

		/* add byte to rx buffer */
		if (unlikely(rx_buff->len >= rx_buff->truesize)) {
			pr_debug("%s: fir frame exceeds %d\n",
				 stir->netdev->name, rx_buff->truesize);
			++stir->netdev->stats.rx_over_errors;
			goto error_recovery;
		}

		rx_buff->data[rx_buff->len++] = byte;
		continue;

	frame_error:
		++stir->netdev->stats.rx_frame_errors;

	error_recovery:
		++stir->netdev->stats.rx_errors;
		rx_buff->state = OUTSIDE_FRAME;
		rx_buff->in_frame = FALSE;
	}
}

/* Unwrap SIR stuffed data and bump it up to IrLAP */
static void stir_sir_chars(struct stir_cb *stir,
			    const __u8 *bytes, int len)
{
	int i;

	for (i = 0; i < len; i++)
		async_unwrap_char(stir->netdev, &stir->netdev->stats,
				  &stir->rx_buff, bytes[i]);
}

static inline void unwrap_chars(struct stir_cb *stir,
				const __u8 *bytes, int length)
{
	if (isfir(stir->speed))
		stir_fir_chars(stir, bytes, length);
	else
		stir_sir_chars(stir, bytes, length);
}

/* Mode parameters for each speed */
static const struct {
	unsigned speed;
	__u8 pdclk;
} stir_modes[] = {
        { 2400,    PDCLK_2400 },
        { 9600,    PDCLK_9600 },
        { 19200,   PDCLK_19200 },
        { 38400,   PDCLK_38400 },
        { 57600,   PDCLK_57600 },
        { 115200,  PDCLK_115200 },
        { 4000000, PDCLK_4000000 },
};


/*
 * Setup chip for speed.
 *  Called at startup to initialize the chip
 *  and on speed changes.
 *
 * Note: Write multiple registers doesn't appear to work
 */
static int change_speed(struct stir_cb *stir, unsigned speed)
{
	int i, err;
	__u8 mode;

	for (i = 0; i < ARRAY_SIZE(stir_modes); ++i) {
		if (speed == stir_modes[i].speed)
			goto found;
	}

	dev_warn(&stir->netdev->dev, "invalid speed %d\n", speed);
	return -EINVAL;

 found:
	pr_debug("speed change from %d to %d\n", stir->speed, speed);

	/* Reset modulator */
	err = write_reg(stir, REG_CTRL1, CTRL1_SRESET);
	if (err)
		goto out;

	/* Undocumented magic to tweak the DPLL */
	err = write_reg(stir, REG_DPLL, 0x15);
	if (err)
		goto out;

	/* Set clock */
	err = write_reg(stir, REG_PDCLK, stir_modes[i].pdclk);
	if (err)
		goto out;

	mode = MODE_NRESET | MODE_FASTRX;
	if (isfir(speed))
		mode |= MODE_FIR | MODE_FFRSTEN;
	else
		mode |= MODE_SIR;

	if (speed == 2400)
		mode |= MODE_2400;

	err = write_reg(stir, REG_MODE, mode);
	if (err)
		goto out;

	/* This resets TEMIC style transceiver if any. */
	err = write_reg(stir, REG_CTRL1,
			CTRL1_SDMODE | (tx_power & 3) << 1);
	if (err)
		goto out;

	err = write_reg(stir, REG_CTRL1, (tx_power & 3) << 1);
	if (err)
		goto out;

	/* Reset sensitivity */
	err = write_reg(stir, REG_CTRL2, (rx_sensitivity & 7) << 5);
 out:
	stir->speed = speed;
	return err;
}

/*
 * Called from net/core when new frame is available.
 */
static netdev_tx_t stir_hard_xmit(struct sk_buff *skb,
					struct net_device *netdev)
{
	struct stir_cb *stir = netdev_priv(netdev);

	netif_stop_queue(netdev);

	/* the IRDA wrapping routines don't deal with non linear skb */
	SKB_LINEAR_ASSERT(skb);

	skb = xchg(&stir->tx_pending, skb);
        wake_up_process(stir->thread);
	
	/* this should never happen unless stop/wakeup problem */
	if (unlikely(skb)) {
		WARN_ON(1);
		dev_kfree_skb(skb);
	}

	return NETDEV_TX_OK;
}

/*
 * Wait for the transmit FIFO to have space for next data
 *
 * If space < 0 then wait till FIFO completely drains.
 * FYI: can take up to 13 seconds at 2400baud.
 */
static int fifo_txwait(struct stir_cb *stir, int space)
{
	int err;
	unsigned long count, status;
	unsigned long prev_count = 0x1fff;

	/* Read FIFO status and count */
	for (;; prev_count = count) {
		err = read_reg(stir, REG_FIFOCTL, stir->fifo_status, 
				   FIFO_REGS_SIZE);
		if (unlikely(err != FIFO_REGS_SIZE)) {
			dev_warn(&stir->netdev->dev,
				 "FIFO register read error: %d\n", err);

			return err;
		}

		status = stir->fifo_status[0];
		count = (unsigned)(stir->fifo_status[2] & 0x1f) << 8 
			| stir->fifo_status[1];

		pr_debug("fifo status 0x%lx count %lu\n", status, count);

		/* is fifo receiving already, or empty */
		if (!(status & FIFOCTL_DIR)
		    || (status & FIFOCTL_EMPTY))
			return 0;

		if (signal_pending(current))
			return -EINTR;

		/* shutting down? */
		if (!netif_running(stir->netdev)
		    || !netif_device_present(stir->netdev))
			return -ESHUTDOWN;

		/* only waiting for some space */
		if (space >= 0 && STIR_FIFO_SIZE - 4 > space + count)
			return 0;

		/* queue confused */
		if (prev_count < count)
			break;

		/* estimate transfer time for remaining chars */
		msleep((count * 8000) / stir->speed);
	}
			
	err = write_reg(stir, REG_FIFOCTL, FIFOCTL_CLR);
	if (err) 
		return err;
	err = write_reg(stir, REG_FIFOCTL, 0);
	if (err)
		return err;

	return 0;
}


/* Wait for turnaround delay before starting transmit.  */
static void turnaround_delay(const struct stir_cb *stir, long us)
{
	long ticks;
	struct timeval now;

	if (us <= 0)
		return;

	do_gettimeofday(&now);
	if (now.tv_sec - stir->rx_time.tv_sec > 0)
		us -= USEC_PER_SEC;
	us -= now.tv_usec - stir->rx_time.tv_usec;
	if (us < 10)
		return;

	ticks = us / (1000000 / HZ);
	if (ticks > 0)
		schedule_timeout_interruptible(1 + ticks);
	else
		udelay(us);
}

/*
 * Start receiver by submitting a request to the receive pipe.
 * If nothing is available it will return after rx_interval.
 */
static int receive_start(struct stir_cb *stir)
{
	/* reset state */
	stir->receiving = 1;

	stir->rx_buff.in_frame = FALSE;
	stir->rx_buff.state = OUTSIDE_FRAME;

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

/* Stop all pending receive Urb's */
static void receive_stop(struct stir_cb *stir)
{
	stir->receiving = 0;
	usb_kill_urb(stir->rx_urb);

	if (stir->rx_buff.in_frame) 
		stir->netdev->stats.collisions++;
}
/*
 * Wrap data in socket buffer and send it.
 */
static void stir_send(struct stir_cb *stir, struct sk_buff *skb)
{
	unsigned wraplen;
	int first_frame = 0;

	/* if receiving, need to turnaround */
	if (stir->receiving) {
		receive_stop(stir);
		turnaround_delay(stir, irda_get_mtt(skb));
		first_frame = 1;
	}

	if (isfir(stir->speed))
		wraplen = wrap_fir_skb(skb, stir->io_buf);
	else
		wraplen = wrap_sir_skb(skb, stir->io_buf);
		
	/* check for space available in fifo */
	if (!first_frame)
		fifo_txwait(stir, wraplen);

	stir->netdev->stats.tx_packets++;
	stir->netdev->stats.tx_bytes += skb->len;
	stir->netdev->trans_start = jiffies;
	pr_debug("send %d (%d)\n", skb->len, wraplen);

	if (usb_bulk_msg(stir->usbdev, usb_sndbulkpipe(stir->usbdev, 1),
			 stir->io_buf, wraplen,
			 NULL, TRANSMIT_TIMEOUT))
		stir->netdev->stats.tx_errors++;
}

/*
 * Transmit state machine thread
 */
static int stir_transmit_thread(void *arg)
{
	struct stir_cb *stir = arg;
	struct net_device *dev = stir->netdev;
	struct sk_buff *skb;

        while (!kthread_should_stop()) {
#ifdef CONFIG_PM
		/* if suspending, then power off and wait */
		if (unlikely(freezing(current))) {
			if (stir->receiving)
				receive_stop(stir);
			else
				fifo_txwait(stir, -1);

			write_reg(stir, REG_CTRL1, CTRL1_TXPWD|CTRL1_RXPWD);

			refrigerator();

			if (change_speed(stir, stir->speed))
				break;
		}
#endif

		/* if something to send? */
		skb = xchg(&stir->tx_pending, NULL);
		if (skb) {
			unsigned new_speed = irda_get_next_speed(skb);
			netif_wake_queue(dev);

			if (skb->len > 0)
				stir_send(stir, skb);
			dev_kfree_skb(skb);

			if ((new_speed != -1) && (stir->speed != new_speed)) {
				if (fifo_txwait(stir, -1) ||
				    change_speed(stir, new_speed))
					break;
			}
			continue;
		}

		/* nothing to send? start receiving */
		if (!stir->receiving 
		    && irda_device_txqueue_empty(dev)) {
			/* Wait otherwise chip gets confused. */
			if (fifo_txwait(stir, -1))
				break;

			if (unlikely(receive_start(stir))) {
				if (net_ratelimit())
					dev_info(&dev->dev,
						 "%s: receive usb submit failed\n",
						 stir->netdev->name);
				stir->receiving = 0;
				msleep(10);
				continue;
			}
		}

		/* sleep if nothing to send */
                set_current_state(TASK_INTERRUPTIBLE);
                schedule();

	}
        return 0;
}


/*
 * USB bulk receive completion callback.
 * Wakes up every ms (usb round trip) with wrapped 
 * data.
 */
static void stir_rcv_irq(struct urb *urb)
{
	struct stir_cb *stir = urb->context;
	int err;

	/* in process of stopping, just drop data */
	if (!netif_running(stir->netdev))
		return;

	/* unlink, shutdown, unplug, other nasties */
	if (urb->status != 0) 
		return;

	if (urb->actual_length > 0) {
		pr_debug("receive %d\n", urb->actual_length);
		unwrap_chars(stir, urb->transfer_buffer,
			     urb->actual_length);
		
		do_gettimeofday(&stir->rx_time);
	}

	/* kernel thread is stopping receiver don't resubmit */
	if (!stir->receiving)
		return;

	/* resubmit existing urb */
	err = usb_submit_urb(urb, GFP_ATOMIC);

	/* in case of error, the kernel thread will restart us */
	if (err) {
		dev_warn(&stir->netdev->dev, "usb receive submit error: %d\n",
			 err);
		stir->receiving = 0;
		wake_up_process(stir->thread);
	}
}

/*
 * Function stir_net_open (dev)
 *
 *    Network device is taken up. Usually this is done by "ifconfig irda0 up"
 */
static int stir_net_open(struct net_device *netdev)
{
	struct stir_cb *stir = netdev_priv(netdev);
	int err;
	char hwname[16];

	err = usb_clear_halt(stir->usbdev, usb_sndbulkpipe(stir->usbdev, 1));
	if (err)
		goto err_out1;
	err = usb_clear_halt(stir->usbdev, usb_rcvbulkpipe(stir->usbdev, 2));
	if (err)
		goto err_out1;

	err = change_speed(stir, 9600);
	if (err)
		goto err_out1;

	err = -ENOMEM;

	/* Initialize for SIR/FIR to copy data directly into skb.  */
	stir->receiving = 0;
	stir->rx_buff.truesize = IRDA_SKB_MAX_MTU;
	stir->rx_buff.skb = dev_alloc_skb(IRDA_SKB_MAX_MTU);
	if (!stir->rx_buff.skb) 
		goto err_out1;

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

	stir->rx_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!stir->rx_urb) 
		goto err_out2;

	stir->io_buf = kmalloc(STIR_FIFO_SIZE, GFP_KERNEL);
	if (!stir->io_buf)
		goto err_out3;

	usb_fill_bulk_urb(stir->rx_urb, stir->usbdev,
			  usb_rcvbulkpipe(stir->usbdev, 2),
			  stir->io_buf, STIR_FIFO_SIZE,
			  stir_rcv_irq, stir);

	stir->fifo_status = kmalloc(FIFO_REGS_SIZE, GFP_KERNEL);
	if (!stir->fifo_status) 
		goto err_out4;
		
	/*
	 * 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", stir->usbdev->devnum);
	stir->irlap = irlap_open(netdev, &stir->qos, hwname);
	if (!stir->irlap) {
		err("stir4200: irlap_open failed");
		goto err_out5;
	}

	/** Start kernel thread for transmit.  */
	stir->thread = kthread_run(stir_transmit_thread, stir,
				   "%s", stir->netdev->name);
        if (IS_ERR(stir->thread)) {
                err = PTR_ERR(stir->thread);
		err("stir4200: unable to start kernel thread");
		goto err_out6;
	}

	netif_start_queue(netdev);

	return 0;

 err_out6:
	irlap_close(stir->irlap);
 err_out5:
	kfree(stir->fifo_status);
 err_out4:
	kfree(stir->io_buf);
 err_out3:
	usb_free_urb(stir->rx_urb);
 err_out2:
	kfree_skb(stir->rx_buff.skb);
 err_out1:
	return err;
}

/*
 * Function stir_net_close (stir)
 *
 *    Network device is taken down. Usually this is done by
 *    "ifconfig irda0 down"
 */
static int stir_net_close(struct net_device *netdev)
{
	struct stir_cb *stir = netdev_priv(netdev);

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

	/* Kill transmit thread */
	kthread_stop(stir->thread);
	kfree(stir->fifo_status);

	/* Mop up receive urb's */
	usb_kill_urb(stir->rx_urb);
	
	kfree(stir->io_buf);
	usb_free_urb(stir->rx_urb);
	kfree_skb(stir->rx_buff.skb);

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

	stir->irlap = NULL;

	return 0;
}

/*
 * IOCTLs : Extra out-of-band network commands...
 */
static int stir_net_ioctl(struct net_device *netdev, struct ifreq *rq, int cmd)
{
	struct if_irda_req *irq = (struct if_irda_req *) rq;
	struct stir_cb *stir = netdev_priv(netdev);
	int ret = 0;

	switch (cmd) {
	case SIOCSBANDWIDTH: /* Set bandwidth */
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;

		/* Check if the device is still there */
		if (netif_device_present(stir->netdev))
			ret = change_speed(stir, irq->ifr_baudrate);
		break;

	case SIOCSMEDIABUSY: /* Set media busy */
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;

		/* Check if the IrDA stack is still there */
		if (netif_running(stir->netdev))
			irda_device_set_media_busy(stir->netdev, TRUE);
		break;

	case SIOCGRECEIVING:
		/* Only approximately true */
		irq->ifr_receiving = stir->receiving;
		break;

	default:
		ret = -EOPNOTSUPP;
	}

	return ret;
}

static const struct net_device_ops stir_netdev_ops = {
	.ndo_open       = stir_net_open,
	.ndo_stop       = stir_net_close,
	.ndo_start_xmit = stir_hard_xmit,
	.ndo_do_ioctl   = stir_net_ioctl,
};

/*
 * This routine is called by the USB subsystem for each new device
 * in the system. We need to check if the device is ours, and in
 * this case start handling it.
 * Note : it might be worth protecting this function by a global
 * spinlock... Or not, because maybe USB already deal with that...
 */
static int stir_probe(struct usb_interface *intf,
		      const struct usb_device_id *id)
{
	struct usb_device *dev = interface_to_usbdev(intf);
	struct stir_cb *stir = NULL;
	struct net_device *net;
	int ret = -ENOMEM;

	/* Allocate network device container. */
	net = alloc_irdadev(sizeof(*stir));
	if(!net)
		goto err_out1;

	SET_NETDEV_DEV(net, &intf->dev);
	stir = netdev_priv(net);
	stir->netdev = net;
	stir->usbdev = dev;

	ret = usb_reset_configuration(dev);
	if (ret != 0) {
		err("stir4200: usb reset configuration failed");
		goto err_out2;
	}

	printk(KERN_INFO "SigmaTel STIr4200 IRDA/USB found at address %d, "
		"Vendor: %x, Product: %x\n",
	       dev->devnum, le16_to_cpu(dev->descriptor.idVendor),
	       le16_to_cpu(dev->descriptor.idProduct));

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

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

	/* Override the network functions we need to use */
	net->netdev_ops = &stir_netdev_ops;

	ret = register_netdev(net);
	if (ret != 0)
		goto err_out2;

	dev_info(&intf->dev, "IrDA: Registered SigmaTel device %s\n",
		 net->name);

	usb_set_intfdata(intf, stir);

	return 0;

err_out2:
	free_netdev(net);
err_out1:
	return ret;
}

/*
 * The current device is removed, the USB layer tell us to shut it down...
 */
static void stir_disconnect(struct usb_interface *intf)
{
	struct stir_cb *stir = usb_get_intfdata(intf);

	if (!stir)
		return;

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

	usb_set_intfdata(intf, NULL);
}

#ifdef CONFIG_PM
/* USB suspend, so power off the transmitter/receiver */
static int stir_suspend(struct usb_interface *intf, pm_message_t message)
{
	struct stir_cb *stir = usb_get_intfdata(intf);

	netif_device_detach(stir->netdev);
	return 0;
}

/* Coming out of suspend, so reset hardware */
static int stir_resume(struct usb_interface *intf)
{
	struct stir_cb *stir = usb_get_intfdata(intf);

	netif_device_attach(stir->netdev);

	/* receiver restarted when send thread wakes up */
	return 0;
}
#endif

/*
 * USB device callbacks
 */
static struct usb_driver irda_driver = {
	.name		= "stir4200",
	.probe		= stir_probe,
	.disconnect	= stir_disconnect,
	.id_table	= dongles,
#ifdef CONFIG_PM
	.suspend	= stir_suspend,
	.resume		= stir_resume,
#endif
};

/*
 * Module insertion
 */
static int __init stir_init(void)
{
	return usb_register(&irda_driver);
}
module_init(stir_init);

/*
 * Module removal
 */
static void __exit stir_cleanup(void)
{
	/* Deregister the driver and remove all pending instances */
	usb_deregister(&irda_driver);
}
module_exit(stir_cleanup);