i4l.c 18.1 KB
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
/*
 * Stuff used by all variants of the driver
 *
 * Copyright (c) 2001 by Stefan Eilers,
 *                       Hansjoerg Lipp <hjlipp@web.de>,
 *                       Tilman Schmidt <tilman@imap.cc>.
 *
 * =====================================================================
 *	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.
 * =====================================================================
 */

#include "gigaset.h"
#include <linux/isdnif.h>
#include <linux/export.h>

#define SBUFSIZE	4096	/* sk_buff payload size */
#define TRANSBUFSIZE	768	/* bytes per skb for transparent receive */
#define HW_HDR_LEN	2	/* Header size used to store ack info */
#define MAX_BUF_SIZE	(SBUFSIZE - HW_HDR_LEN)	/* max data packet from LL */

/* == Handling of I4L IO =====================================================*/

/* writebuf_from_LL
 * called by LL to transmit data on an open channel
 * inserts the buffer data into the send queue and starts the transmission
 * Note that this operation must not sleep!
 * When the buffer is processed completely, gigaset_skb_sent() should be called.
 * parameters:
 *	driverID	driver ID as assigned by LL
 *	channel		channel number
 *	ack		if != 0 LL wants to be notified on completion via
 *			statcallb(ISDN_STAT_BSENT)
 *	skb		skb containing data to send
 * return value:
 *	number of accepted bytes
 *	0 if temporarily unable to accept data (out of buffer space)
 *	<0 on error (eg. -EINVAL)
 */
static int writebuf_from_LL(int driverID, int channel, int ack,
			    struct sk_buff *skb)
{
	struct cardstate *cs = gigaset_get_cs_by_id(driverID);
	struct bc_state *bcs;
	unsigned char *ack_header;
	unsigned len;

	if (!cs) {
		pr_err("%s: invalid driver ID (%d)\n", __func__, driverID);
		return -ENODEV;
	}
	if (channel < 0 || channel >= cs->channels) {
		dev_err(cs->dev, "%s: invalid channel ID (%d)\n",
			__func__, channel);
		return -ENODEV;
	}
	bcs = &cs->bcs[channel];

	/* can only handle linear sk_buffs */
	if (skb_linearize(skb) < 0) {
		dev_err(cs->dev, "%s: skb_linearize failed\n", __func__);
		return -ENOMEM;
	}
	len = skb->len;

	gig_dbg(DEBUG_LLDATA,
		"Receiving data from LL (id: %d, ch: %d, ack: %d, sz: %d)",
		driverID, channel, ack, len);

	if (!len) {
		if (ack)
			dev_notice(cs->dev, "%s: not ACKing empty packet\n",
				   __func__);
		return 0;
	}
	if (len > MAX_BUF_SIZE) {
		dev_err(cs->dev, "%s: packet too large (%d bytes)\n",
			__func__, len);
		return -EINVAL;
	}

	/* set up acknowledgement header */
	if (skb_headroom(skb) < HW_HDR_LEN) {
		/* should never happen */
		dev_err(cs->dev, "%s: insufficient skb headroom\n", __func__);
		return -ENOMEM;
	}
	skb_set_mac_header(skb, -HW_HDR_LEN);
	skb->mac_len = HW_HDR_LEN;
	ack_header = skb_mac_header(skb);
	if (ack) {
		ack_header[0] = len & 0xff;
		ack_header[1] = len >> 8;
	} else {
		ack_header[0] = ack_header[1] = 0;
	}
	gig_dbg(DEBUG_MCMD, "skb: len=%u, ack=%d: %02x %02x",
		len, ack, ack_header[0], ack_header[1]);

	/* pass to device-specific module */
	return cs->ops->send_skb(bcs, skb);
}

/**
 * gigaset_skb_sent() - acknowledge sending an skb
 * @bcs:	B channel descriptor structure.
 * @skb:	sent data.
 *
 * Called by hardware module {bas,ser,usb}_gigaset when the data in a
 * skb has been successfully sent, for signalling completion to the LL.
 */
void gigaset_skb_sent(struct bc_state *bcs, struct sk_buff *skb)
{
	isdn_if *iif = bcs->cs->iif;
	unsigned char *ack_header = skb_mac_header(skb);
	unsigned len;
	isdn_ctrl response;

	++bcs->trans_up;

	if (skb->len)
		dev_warn(bcs->cs->dev, "%s: skb->len==%d\n",
			 __func__, skb->len);

	len = ack_header[0] + ((unsigned) ack_header[1] << 8);
	if (len) {
		gig_dbg(DEBUG_MCMD, "ACKing to LL (id: %d, ch: %d, sz: %u)",
			bcs->cs->myid, bcs->channel, len);

		response.driver = bcs->cs->myid;
		response.command = ISDN_STAT_BSENT;
		response.arg = bcs->channel;
		response.parm.length = len;
		iif->statcallb(&response);
	}
}
EXPORT_SYMBOL_GPL(gigaset_skb_sent);

/**
 * gigaset_skb_rcvd() - pass received skb to LL
 * @bcs:	B channel descriptor structure.
 * @skb:	received data.
 *
 * Called by hardware module {bas,ser,usb}_gigaset when user data has
 * been successfully received, for passing to the LL.
 * Warning: skb must not be accessed anymore!
 */
void gigaset_skb_rcvd(struct bc_state *bcs, struct sk_buff *skb)
{
	isdn_if *iif = bcs->cs->iif;

	iif->rcvcallb_skb(bcs->cs->myid, bcs->channel, skb);
	bcs->trans_down++;
}
EXPORT_SYMBOL_GPL(gigaset_skb_rcvd);

/**
 * gigaset_isdn_rcv_err() - signal receive error
 * @bcs:	B channel descriptor structure.
 *
 * Called by hardware module {bas,ser,usb}_gigaset when a receive error
 * has occurred, for signalling to the LL.
 */
void gigaset_isdn_rcv_err(struct bc_state *bcs)
{
	isdn_if *iif = bcs->cs->iif;
	isdn_ctrl response;

	/* if currently ignoring packets, just count down */
	if (bcs->ignore) {
		bcs->ignore--;
		return;
	}

	/* update statistics */
	bcs->corrupted++;

	/* error -> LL */
	gig_dbg(DEBUG_CMD, "sending L1ERR");
	response.driver = bcs->cs->myid;
	response.command = ISDN_STAT_L1ERR;
	response.arg = bcs->channel;
	response.parm.errcode = ISDN_STAT_L1ERR_RECV;
	iif->statcallb(&response);
}
EXPORT_SYMBOL_GPL(gigaset_isdn_rcv_err);

/* This function will be called by LL to send commands
 * NOTE: LL ignores the returned value, for commands other than ISDN_CMD_IOCTL,
 * so don't put too much effort into it.
 */
static int command_from_LL(isdn_ctrl *cntrl)
{
	struct cardstate *cs;
	struct bc_state *bcs;
	int retval = 0;
	char **commands;
	int ch;
	int i;
	size_t l;

	gig_dbg(DEBUG_CMD, "driver: %d, command: %d, arg: 0x%lx",
		cntrl->driver, cntrl->command, cntrl->arg);

	cs = gigaset_get_cs_by_id(cntrl->driver);
	if (cs == NULL) {
		pr_err("%s: invalid driver ID (%d)\n", __func__, cntrl->driver);
		return -ENODEV;
	}
	ch = cntrl->arg & 0xff;

	switch (cntrl->command) {
	case ISDN_CMD_IOCTL:
		dev_warn(cs->dev, "ISDN_CMD_IOCTL not supported\n");
		return -EINVAL;

	case ISDN_CMD_DIAL:
		gig_dbg(DEBUG_CMD,
			"ISDN_CMD_DIAL (phone: %s, msn: %s, si1: %d, si2: %d)",
			cntrl->parm.setup.phone, cntrl->parm.setup.eazmsn,
			cntrl->parm.setup.si1, cntrl->parm.setup.si2);

		if (ch >= cs->channels) {
			dev_err(cs->dev,
				"ISDN_CMD_DIAL: invalid channel (%d)\n", ch);
			return -EINVAL;
		}
		bcs = cs->bcs + ch;
		if (gigaset_get_channel(bcs) < 0) {
			dev_err(cs->dev, "ISDN_CMD_DIAL: channel not free\n");
			return -EBUSY;
		}
		switch (bcs->proto2) {
		case L2_HDLC:
			bcs->rx_bufsize = SBUFSIZE;
			break;
		default:			/* assume transparent */
			bcs->rx_bufsize = TRANSBUFSIZE;
		}
		dev_kfree_skb(bcs->rx_skb);
		gigaset_new_rx_skb(bcs);

		commands = kzalloc(AT_NUM * (sizeof *commands), GFP_ATOMIC);
		if (!commands) {
			gigaset_free_channel(bcs);
			dev_err(cs->dev, "ISDN_CMD_DIAL: out of memory\n");
			return -ENOMEM;
		}

		l = 3 + strlen(cntrl->parm.setup.phone);
		commands[AT_DIAL] = kmalloc(l, GFP_ATOMIC);
		if (!commands[AT_DIAL])
			goto oom;
		if (cntrl->parm.setup.phone[0] == '*' &&
		    cntrl->parm.setup.phone[1] == '*') {
			/* internal call: translate ** prefix to CTP value */
			commands[AT_TYPE] = kstrdup("^SCTP=0\r", GFP_ATOMIC);
			if (!commands[AT_TYPE])
				goto oom;
			snprintf(commands[AT_DIAL], l,
				 "D%s\r", cntrl->parm.setup.phone + 2);
		} else {
			commands[AT_TYPE] = kstrdup("^SCTP=1\r", GFP_ATOMIC);
			if (!commands[AT_TYPE])
				goto oom;
			snprintf(commands[AT_DIAL], l,
				 "D%s\r", cntrl->parm.setup.phone);
		}

		l = strlen(cntrl->parm.setup.eazmsn);
		if (l) {
			l += 8;
			commands[AT_MSN] = kmalloc(l, GFP_ATOMIC);
			if (!commands[AT_MSN])
				goto oom;
			snprintf(commands[AT_MSN], l, "^SMSN=%s\r",
				 cntrl->parm.setup.eazmsn);
		}

		switch (cntrl->parm.setup.si1) {
		case 1:		/* audio */
			/* BC = 9090A3: 3.1 kHz audio, A-law */
			commands[AT_BC] = kstrdup("^SBC=9090A3\r", GFP_ATOMIC);
			if (!commands[AT_BC])
				goto oom;
			break;
		case 7:		/* data */
		default:	/* hope the app knows what it is doing */
			/* BC = 8890: unrestricted digital information */
			commands[AT_BC] = kstrdup("^SBC=8890\r", GFP_ATOMIC);
			if (!commands[AT_BC])
				goto oom;
		}
		/* ToDo: other si1 values, inspect si2, set HLC/LLC */

		commands[AT_PROTO] = kmalloc(9, GFP_ATOMIC);
		if (!commands[AT_PROTO])
			goto oom;
		snprintf(commands[AT_PROTO], 9, "^SBPR=%u\r", bcs->proto2);

		commands[AT_ISO] = kmalloc(9, GFP_ATOMIC);
		if (!commands[AT_ISO])
			goto oom;
		snprintf(commands[AT_ISO], 9, "^SISO=%u\r",
			 (unsigned) bcs->channel + 1);

		if (!gigaset_add_event(cs, &bcs->at_state, EV_DIAL, commands,
				       bcs->at_state.seq_index, NULL)) {
			for (i = 0; i < AT_NUM; ++i)
				kfree(commands[i]);
			kfree(commands);
			gigaset_free_channel(bcs);
			return -ENOMEM;
		}
		gigaset_schedule_event(cs);
		break;
	case ISDN_CMD_ACCEPTD:
		gig_dbg(DEBUG_CMD, "ISDN_CMD_ACCEPTD");
		if (ch >= cs->channels) {
			dev_err(cs->dev,
				"ISDN_CMD_ACCEPTD: invalid channel (%d)\n", ch);
			return -EINVAL;
		}
		bcs = cs->bcs + ch;
		switch (bcs->proto2) {
		case L2_HDLC:
			bcs->rx_bufsize = SBUFSIZE;
			break;
		default:			/* assume transparent */
			bcs->rx_bufsize = TRANSBUFSIZE;
		}
		dev_kfree_skb(bcs->rx_skb);
		gigaset_new_rx_skb(bcs);
		if (!gigaset_add_event(cs, &bcs->at_state,
				       EV_ACCEPT, NULL, 0, NULL))
			return -ENOMEM;
		gigaset_schedule_event(cs);

		break;
	case ISDN_CMD_HANGUP:
		gig_dbg(DEBUG_CMD, "ISDN_CMD_HANGUP");
		if (ch >= cs->channels) {
			dev_err(cs->dev,
				"ISDN_CMD_HANGUP: invalid channel (%d)\n", ch);
			return -EINVAL;
		}
		bcs = cs->bcs + ch;
		if (!gigaset_add_event(cs, &bcs->at_state,
				       EV_HUP, NULL, 0, NULL))
			return -ENOMEM;
		gigaset_schedule_event(cs);

		break;
	case ISDN_CMD_CLREAZ: /* Do not signal incoming signals */
		dev_info(cs->dev, "ignoring ISDN_CMD_CLREAZ\n");
		break;
	case ISDN_CMD_SETEAZ: /* Signal incoming calls for given MSN */
		dev_info(cs->dev, "ignoring ISDN_CMD_SETEAZ (%s)\n",
			 cntrl->parm.num);
		break;
	case ISDN_CMD_SETL2: /* Set L2 to given protocol */
		if (ch >= cs->channels) {
			dev_err(cs->dev,
				"ISDN_CMD_SETL2: invalid channel (%d)\n", ch);
			return -EINVAL;
		}
		bcs = cs->bcs + ch;
		if (bcs->chstate & CHS_D_UP) {
			dev_err(cs->dev,
				"ISDN_CMD_SETL2: channel active (%d)\n", ch);
			return -EINVAL;
		}
		switch (cntrl->arg >> 8) {
		case ISDN_PROTO_L2_HDLC:
			gig_dbg(DEBUG_CMD, "ISDN_CMD_SETL2: setting L2_HDLC");
			bcs->proto2 = L2_HDLC;
			break;
		case ISDN_PROTO_L2_TRANS:
			gig_dbg(DEBUG_CMD, "ISDN_CMD_SETL2: setting L2_VOICE");
			bcs->proto2 = L2_VOICE;
			break;
		default:
			dev_err(cs->dev,
				"ISDN_CMD_SETL2: unsupported protocol (%lu)\n",
				cntrl->arg >> 8);
			return -EINVAL;
		}
		break;
	case ISDN_CMD_SETL3: /* Set L3 to given protocol */
		gig_dbg(DEBUG_CMD, "ISDN_CMD_SETL3");
		if (ch >= cs->channels) {
			dev_err(cs->dev,
				"ISDN_CMD_SETL3: invalid channel (%d)\n", ch);
			return -EINVAL;
		}

		if (cntrl->arg >> 8 != ISDN_PROTO_L3_TRANS) {
			dev_err(cs->dev,
				"ISDN_CMD_SETL3: unsupported protocol (%lu)\n",
				cntrl->arg >> 8);
			return -EINVAL;
		}

		break;

	default:
		gig_dbg(DEBUG_CMD, "unknown command %d from LL",
			cntrl->command);
		return -EINVAL;
	}

	return retval;

oom:
	dev_err(bcs->cs->dev, "out of memory\n");
	for (i = 0; i < AT_NUM; ++i)
		kfree(commands[i]);
	kfree(commands);
	gigaset_free_channel(bcs);
	return -ENOMEM;
}

static void gigaset_i4l_cmd(struct cardstate *cs, int cmd)
{
	isdn_if *iif = cs->iif;
	isdn_ctrl command;

	command.driver = cs->myid;
	command.command = cmd;
	command.arg = 0;
	iif->statcallb(&command);
}

static void gigaset_i4l_channel_cmd(struct bc_state *bcs, int cmd)
{
	isdn_if *iif = bcs->cs->iif;
	isdn_ctrl command;

	command.driver = bcs->cs->myid;
	command.command = cmd;
	command.arg = bcs->channel;
	iif->statcallb(&command);
}

/**
 * gigaset_isdn_icall() - signal incoming call
 * @at_state:	connection state structure.
 *
 * Called by main module to notify the LL that an incoming call has been
 * received. @at_state contains the parameters of the call.
 *
 * Return value: call disposition (ICALL_*)
 */
int gigaset_isdn_icall(struct at_state_t *at_state)
{
	struct cardstate *cs = at_state->cs;
	struct bc_state *bcs = at_state->bcs;
	isdn_if *iif = cs->iif;
	isdn_ctrl response;
	int retval;

	/* fill ICALL structure */
	response.parm.setup.si1 = 0;	/* default: unknown */
	response.parm.setup.si2 = 0;
	response.parm.setup.screen = 0;
	response.parm.setup.plan = 0;
	if (!at_state->str_var[STR_ZBC]) {
		/* no BC (internal call): assume speech, A-law */
		response.parm.setup.si1 = 1;
	} else if (!strcmp(at_state->str_var[STR_ZBC], "8890")) {
		/* unrestricted digital information */
		response.parm.setup.si1 = 7;
	} else if (!strcmp(at_state->str_var[STR_ZBC], "8090A3")) {
		/* speech, A-law */
		response.parm.setup.si1 = 1;
	} else if (!strcmp(at_state->str_var[STR_ZBC], "9090A3")) {
		/* 3,1 kHz audio, A-law */
		response.parm.setup.si1 = 1;
		response.parm.setup.si2 = 2;
	} else {
		dev_warn(cs->dev, "RING ignored - unsupported BC %s\n",
			 at_state->str_var[STR_ZBC]);
		return ICALL_IGNORE;
	}
	if (at_state->str_var[STR_NMBR]) {
		strlcpy(response.parm.setup.phone, at_state->str_var[STR_NMBR],
			sizeof response.parm.setup.phone);
	} else
		response.parm.setup.phone[0] = 0;
	if (at_state->str_var[STR_ZCPN]) {
		strlcpy(response.parm.setup.eazmsn, at_state->str_var[STR_ZCPN],
			sizeof response.parm.setup.eazmsn);
	} else
		response.parm.setup.eazmsn[0] = 0;

	if (!bcs) {
		dev_notice(cs->dev, "no channel for incoming call\n");
		response.command = ISDN_STAT_ICALLW;
		response.arg = 0;
	} else {
		gig_dbg(DEBUG_CMD, "Sending ICALL");
		response.command = ISDN_STAT_ICALL;
		response.arg = bcs->channel;
	}
	response.driver = cs->myid;
	retval = iif->statcallb(&response);
	gig_dbg(DEBUG_CMD, "Response: %d", retval);
	switch (retval) {
	case 0:	/* no takers */
		return ICALL_IGNORE;
	case 1:	/* alerting */
		bcs->chstate |= CHS_NOTIFY_LL;
		return ICALL_ACCEPT;
	case 2:	/* reject */
		return ICALL_REJECT;
	case 3:	/* incomplete */
		dev_warn(cs->dev,
			 "LL requested unsupported feature: Incomplete Number\n");
		return ICALL_IGNORE;
	case 4:	/* proceeding */
		/* Gigaset will send ALERTING anyway.
		 * There doesn't seem to be a way to avoid this.
		 */
		return ICALL_ACCEPT;
	case 5:	/* deflect */
		dev_warn(cs->dev,
			 "LL requested unsupported feature: Call Deflection\n");
		return ICALL_IGNORE;
	default:
		dev_err(cs->dev, "LL error %d on ICALL\n", retval);
		return ICALL_IGNORE;
	}
}

/**
 * gigaset_isdn_connD() - signal D channel connect
 * @bcs:	B channel descriptor structure.
 *
 * Called by main module to notify the LL that the D channel connection has
 * been established.
 */
void gigaset_isdn_connD(struct bc_state *bcs)
{
	gig_dbg(DEBUG_CMD, "sending DCONN");
	gigaset_i4l_channel_cmd(bcs, ISDN_STAT_DCONN);
}

/**
 * gigaset_isdn_hupD() - signal D channel hangup
 * @bcs:	B channel descriptor structure.
 *
 * Called by main module to notify the LL that the D channel connection has
 * been shut down.
 */
void gigaset_isdn_hupD(struct bc_state *bcs)
{
	gig_dbg(DEBUG_CMD, "sending DHUP");
	gigaset_i4l_channel_cmd(bcs, ISDN_STAT_DHUP);
}

/**
 * gigaset_isdn_connB() - signal B channel connect
 * @bcs:	B channel descriptor structure.
 *
 * Called by main module to notify the LL that the B channel connection has
 * been established.
 */
void gigaset_isdn_connB(struct bc_state *bcs)
{
	gig_dbg(DEBUG_CMD, "sending BCONN");
	gigaset_i4l_channel_cmd(bcs, ISDN_STAT_BCONN);
}

/**
 * gigaset_isdn_hupB() - signal B channel hangup
 * @bcs:	B channel descriptor structure.
 *
 * Called by main module to notify the LL that the B channel connection has
 * been shut down.
 */
void gigaset_isdn_hupB(struct bc_state *bcs)
{
	gig_dbg(DEBUG_CMD, "sending BHUP");
	gigaset_i4l_channel_cmd(bcs, ISDN_STAT_BHUP);
}

/**
 * gigaset_isdn_start() - signal device availability
 * @cs:		device descriptor structure.
 *
 * Called by main module to notify the LL that the device is available for
 * use.
 */
void gigaset_isdn_start(struct cardstate *cs)
{
	gig_dbg(DEBUG_CMD, "sending RUN");
	gigaset_i4l_cmd(cs, ISDN_STAT_RUN);
}

/**
 * gigaset_isdn_stop() - signal device unavailability
 * @cs:		device descriptor structure.
 *
 * Called by main module to notify the LL that the device is no longer
 * available for use.
 */
void gigaset_isdn_stop(struct cardstate *cs)
{
	gig_dbg(DEBUG_CMD, "sending STOP");
	gigaset_i4l_cmd(cs, ISDN_STAT_STOP);
}

/**
 * gigaset_isdn_regdev() - register to LL
 * @cs:		device descriptor structure.
 * @isdnid:	device name.
 *
 * Return value: 0 on success, error code < 0 on failure
 */
int gigaset_isdn_regdev(struct cardstate *cs, const char *isdnid)
{
	isdn_if *iif;

	iif = kmalloc(sizeof *iif, GFP_KERNEL);
	if (!iif) {
		pr_err("out of memory\n");
		return -ENOMEM;
	}

	if (snprintf(iif->id, sizeof iif->id, "%s_%u", isdnid, cs->minor_index)
	    >= sizeof iif->id) {
		pr_err("ID too long: %s\n", isdnid);
		kfree(iif);
		return -EINVAL;
	}

	iif->owner = THIS_MODULE;
	iif->channels = cs->channels;
	iif->maxbufsize = MAX_BUF_SIZE;
	iif->features = ISDN_FEATURE_L2_TRANS |
		ISDN_FEATURE_L2_HDLC |
		ISDN_FEATURE_L2_X75I |
		ISDN_FEATURE_L3_TRANS |
		ISDN_FEATURE_P_EURO;
	iif->hl_hdrlen = HW_HDR_LEN;		/* Area for storing ack */
	iif->command = command_from_LL;
	iif->writebuf_skb = writebuf_from_LL;
	iif->writecmd = NULL;			/* Don't support isdnctrl */
	iif->readstat = NULL;			/* Don't support isdnctrl */
	iif->rcvcallb_skb = NULL;		/* Will be set by LL */
	iif->statcallb = NULL;			/* Will be set by LL */

	if (!register_isdn(iif)) {
		pr_err("register_isdn failed\n");
		kfree(iif);
		return -EINVAL;
	}

	cs->iif = iif;
	cs->myid = iif->channels;		/* Set my device id */
	cs->hw_hdr_len = HW_HDR_LEN;
	return 0;
}

/**
 * gigaset_isdn_unregdev() - unregister device from LL
 * @cs:		device descriptor structure.
 */
void gigaset_isdn_unregdev(struct cardstate *cs)
{
	gig_dbg(DEBUG_CMD, "sending UNLOAD");
	gigaset_i4l_cmd(cs, ISDN_STAT_UNLOAD);
	kfree(cs->iif);
	cs->iif = NULL;
}

/**
 * gigaset_isdn_regdrv() - register driver to LL
 */
void gigaset_isdn_regdrv(void)
{
	pr_info("ISDN4Linux interface\n");
	/* nothing to do */
}

/**
 * gigaset_isdn_unregdrv() - unregister driver from LL
 */
void gigaset_isdn_unregdrv(void)
{
	/* nothing to do */
}