aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/usb/host/fhci-tds.c
blob: 7be548ca21834bd87de25d231356ede4cac16859 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
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
/*
 * Freescale QUICC Engine USB Host Controller Driver
 *
 * Copyright (c) Freescale Semicondutor, Inc. 2006.
 *               Shlomi Gridish <gridish@freescale.com>
 *               Jerry Huang <Chang-Ming.Huang@freescale.com>
 * Copyright (c) Logic Product Development, Inc. 2007
 *               Peter Barada <peterb@logicpd.com>
 * Copyright (c) MontaVista Software, Inc. 2008.
 *               Anton Vorontsov <avorontsov@ru.mvista.com>
 *
 * 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 <linux/kernel.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/io.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>
#include "fhci.h"

#define DUMMY_BD_BUFFER  0xdeadbeef
#define DUMMY2_BD_BUFFER 0xbaadf00d

/* Transaction Descriptors bits */
#define TD_R		0x8000 /* ready bit */
#define TD_W		0x2000 /* wrap bit */
#define TD_I		0x1000 /* interrupt on completion */
#define TD_L		0x0800 /* last */
#define TD_TC		0x0400 /* transmit CRC */
#define TD_CNF		0x0200 /* CNF - Must be always 1 */
#define TD_LSP		0x0100 /* Low-speed transaction */
#define TD_PID		0x00c0 /* packet id */
#define TD_RXER		0x0020 /* Rx error or not */

#define TD_NAK		0x0010 /* No ack. */
#define TD_STAL		0x0008 /* Stall recieved */
#define TD_TO		0x0004 /* time out */
#define TD_UN		0x0002 /* underrun */
#define TD_NO		0x0010 /* Rx Non Octet Aligned Packet */
#define TD_AB		0x0008 /* Frame Aborted */
#define TD_CR		0x0004 /* CRC Error */
#define TD_OV		0x0002 /* Overrun */
#define TD_BOV		0x0001 /* Buffer Overrun */

#define TD_ERRORS	(TD_NAK | TD_STAL | TD_TO | TD_UN | \
			 TD_NO | TD_AB | TD_CR | TD_OV | TD_BOV)

#define TD_PID_DATA0	0x0080 /* Data 0 toggle */
#define TD_PID_DATA1	0x00c0 /* Data 1 toggle */
#define TD_PID_TOGGLE	0x00c0 /* Data 0/1 toggle mask */

#define TD_TOK_SETUP	0x0000
#define TD_TOK_OUT	0x4000
#define TD_TOK_IN	0x8000
#define TD_ISO		0x1000
#define TD_ENDP		0x0780
#define TD_ADDR		0x007f

#define TD_ENDP_SHIFT 7

struct usb_td {
	__be16 status;
	__be16 length;
	__be32 buf_ptr;
	__be16 extra;
	__be16 reserved;
};

static struct usb_td __iomem *next_bd(struct usb_td __iomem *base,
				      struct usb_td __iomem *td,
				      u16 status)
{
	if (status & TD_W)
		return base;
	else
		return ++td;
}

void fhci_push_dummy_bd(struct endpoint *ep)
{
	if (ep->already_pushed_dummy_bd == false) {
		u16 td_status = in_be16(&ep->empty_td->status);

		out_be32(&ep->empty_td->buf_ptr, DUMMY_BD_BUFFER);
		/* get the next TD in the ring */
		ep->empty_td = next_bd(ep->td_base, ep->empty_td, td_status);
		ep->already_pushed_dummy_bd = true;
	}
}

/* destroy an USB endpoint */
void fhci_ep0_free(struct fhci_usb *usb)
{
	struct endpoint *ep;
	int size;

	ep = usb->ep0;
	if (ep) {
		if (ep->td_base)
			cpm_muram_free(cpm_muram_offset(ep->td_base));

		if (kfifo_initialized(&ep->conf_frame_Q)) {
			size = cq_howmany(&ep->conf_frame_Q);
			for (; size; size--) {
				struct packet *pkt = cq_get(&ep->conf_frame_Q);

				kfree(pkt);
			}
			cq_delete(&ep->conf_frame_Q);
		}

		if (kfifo_initialized(&ep->empty_frame_Q)) {
			size = cq_howmany(&ep->empty_frame_Q);
			for (; size; size--) {
				struct packet *pkt = cq_get(&ep->empty_frame_Q);

				kfree(pkt);
			}
			cq_delete(&ep->empty_frame_Q);
		}

		if (kfifo_initialized(&ep->dummy_packets_Q)) {
			size = cq_howmany(&ep->dummy_packets_Q);
			for (; size; size--) {
				u8 *buff = cq_get(&ep->dummy_packets_Q);

				kfree(buff);
			}
			cq_delete(&ep->dummy_packets_Q);
		}

		kfree(ep);
		usb->ep0 = NULL;
	}
}

/*
 * create the endpoint structure
 *
 * arguments:
 * usb		A pointer to the data structure of the USB
 * data_mem	The data memory partition(BUS)
 * ring_len	TD ring length
 */
u32 fhci_create_ep(struct fhci_usb *usb, enum fhci_mem_alloc data_mem,
			   u32 ring_len)
{
	struct endpoint *ep;
	struct usb_td __iomem *td;
	unsigned long ep_offset;
	char *err_for = "enpoint PRAM";
	int ep_mem_size;
	u32 i;

	/* we need at least 3 TDs in the ring */
	if (!(ring_len > 2)) {
		fhci_err(usb->fhci, "illegal TD ring length parameters\n");
		return -EINVAL;
	}

	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
	if (!ep)
		return -ENOMEM;

	ep_mem_size = ring_len * sizeof(*td) + sizeof(struct fhci_ep_pram);
	ep_offset = cpm_muram_alloc(ep_mem_size, 32);
	if (IS_ERR_VALUE(ep_offset))
		goto err;
	ep->td_base = cpm_muram_addr(ep_offset);

	/* zero all queue pointers */
	if (cq_new(&ep->conf_frame_Q, ring_len + 2) ||
	    cq_new(&ep->empty_frame_Q, ring_len + 2) ||
	    cq_new(&ep->dummy_packets_Q, ring_len + 2)) {
		err_for = "frame_queues";
		goto err;
	}

	for (i = 0; i < (ring_len + 1); i++) {
		struct packet *pkt;
		u8 *buff;

		pkt = kmalloc(sizeof(*pkt), GFP_KERNEL);
		if (!pkt) {
			err_for = "frame";
			goto err;
		}

		buff = kmalloc(1028 * sizeof(*buff), GFP_KERNEL);
		if (!buff) {
			kfree(pkt);
			err_for = "buffer";
			goto err;
		}
		cq_put(&ep->empty_frame_Q, pkt);
		cq_put(&ep->dummy_packets_Q, buff);
	}

	/* we put the endpoint parameter RAM right behind the TD ring */
	ep->ep_pram_ptr = (void __iomem *)ep->td_base + sizeof(*td) * ring_len;

	ep->conf_td = ep->td_base;
	ep->empty_td = ep->td_base;

	ep->already_pushed_dummy_bd = false;

	/* initialize tds */
	td = ep->td_base;
	for (i = 0; i < ring_len; i++) {
		out_be32(&td->buf_ptr, 0);
		out_be16(&td->status, 0);
		out_be16(&td->length, 0);
		out_be16(&td->extra, 0);
		td++;
	}
	td--;
	out_be16(&td->status, TD_W); /* for last TD set Wrap bit */
	out_be16(&td->length, 0);

	/* endpoint structure has been created */
	usb->ep0 = ep;

	return 0;
err:
	fhci_ep0_free(usb);
	kfree(ep);
	fhci_err(usb->fhci, "no memory for the %s\n", err_for);
	return -ENOMEM;
}

/*
 * initialize the endpoint register according to the given parameters
 *
 * artuments:
 * usb		A pointer to the data strucutre of the USB
 * ep		A pointer to the endpoint structre
 * data_mem	The data memory partition(BUS)
 */
void fhci_init_ep_registers(struct fhci_usb *usb, struct endpoint *ep,
			    enum fhci_mem_alloc data_mem)
{
	u8 rt;

	/* set the endpoint registers according to the endpoint */
	out_be16(&usb->fhci->regs->usb_ep[0],
		 USB_TRANS_CTR | USB_EP_MF | USB_EP_RTE);
	out_be16(&usb->fhci->pram->ep_ptr[0],
		 cpm_muram_offset(ep->ep_pram_ptr));

	rt = (BUS_MODE_BO_BE | BUS_MODE_GBL);
#ifdef MULTI_DATA_BUS
	if (data_mem == MEM_SECONDARY)
		rt |= BUS_MODE_DTB;
#endif
	out_8(&ep->ep_pram_ptr->rx_func_code, rt);
	out_8(&ep->ep_pram_ptr->tx_func_code, rt);
	out_be16(&ep->ep_pram_ptr->rx_buff_len, 1028);
	out_be16(&ep->ep_pram_ptr->rx_base, 0);
	out_be16(&ep->ep_pram_ptr->tx_base, cpm_muram_offset(ep->td_base));
	out_be16(&ep->ep_pram_ptr->rx_bd_ptr, 0);
	out_be16(&ep->ep_pram_ptr->tx_bd_ptr, cpm_muram_offset(ep->td_base));
	out_be32(&ep->ep_pram_ptr->tx_state, 0);
}

/*
 * Collect the submitted frames and inform the application about them
 * It is also prepearing the TDs for new frames. If the Tx interrupts
 * are diabled, the application should call that routine to get
 * confirmation about the submitted frames. Otherwise, the routine is
 * called frome the interrupt service routine during the Tx interrupt.
 * In that case the application is informed by calling the application
 * specific 'fhci_transaction_confirm' routine
 */
static void fhci_td_transaction_confirm(struct fhci_usb *usb)
{
	struct endpoint *ep = usb->ep0;
	struct packet *pkt;
	struct usb_td __iomem *td;
	u16 extra_data;
	u16 td_status;
	u16 td_length;
	u32 buf;

	/*
	 * collect transmitted BDs from the chip. The routine clears all BDs
	 * with R bit = 0 and the pointer to data buffer is not NULL, that is
	 * BDs which point to the transmitted data buffer
	 */
	while (1) {
		td = ep->conf_td;
		td_status = in_be16(&td->status);
		td_length = in_be16(&td->length);
		buf = in_be32(&td->buf_ptr);
		extra_data = in_be16(&td->extra);

		/* check if the TD is empty */
		if (!(!(td_status & TD_R) && ((td_status & ~TD_W) || buf)))
			break;
		/* check if it is a dummy buffer */
		else if ((buf == DUMMY_BD_BUFFER) && !(td_status & ~TD_W))
			break;

		/* mark TD as empty */
		clrbits16(&td->status, ~TD_W);
		out_be16(&td->length, 0);
		out_be32(&td->buf_ptr, 0);
		out_be16(&td->extra, 0);
		/* advance the TD pointer */
		ep->conf_td = next_bd(ep->td_base, ep->conf_td, td_status);

		/* check if it is a dummy buffer(type2) */
		if ((buf == DUMMY2_BD_BUFFER) && !(td_status & ~TD_W))
			continue;

		pkt = cq_get(&ep->conf_frame_Q);
		if (!pkt)
			fhci_err(usb->fhci, "no frame to confirm\n");

		if (td_status & TD_ERRORS) {
			if (td_status & TD_RXER) {
				if (td_status & TD_CR)
					pkt->status = USB_TD_RX_ER_CRC;
				else if (td_status & TD_AB)
					pkt->status = USB_TD_RX_ER_BITSTUFF;
				else if (td_status & TD_OV)
					pkt->status = USB_TD_RX_ER_OVERUN;
				else if (td_status & TD_BOV)
					pkt->status = USB_TD_RX_DATA_OVERUN;
				else if (td_status & TD_NO)
					pkt->status = USB_TD_RX_ER_NONOCT;
				else
					fhci_err(usb->fhci, "illegal error "
						 "occured\n");
			} else if (td_status & TD_NAK)
				pkt->status = USB_TD_TX_ER_NAK;
			else if (td_status & TD_TO)
				pkt->status = USB_TD_TX_ER_TIMEOUT;
			else if (td_status & TD_UN)
				pkt->status = USB_TD_TX_ER_UNDERUN;
			else if (td_status & TD_STAL)
				pkt->status = USB_TD_TX_ER_STALL;
			else
				fhci_err(usb->fhci, "illegal error occured\n");
		} else if ((extra_data & TD_TOK_IN) &&
				pkt->len > td_length - CRC_SIZE) {
			pkt->status = USB_TD_RX_DATA_UNDERUN;
		}

		if (extra_data & TD_TOK_IN)
			pkt->len = td_length - CRC_SIZE;
		else if (pkt->info & PKT_ZLP)
			pkt->len = 0;
		else
			pkt->len = td_length;

		fhci_transaction_confirm(usb, pkt);
	}
}

/*
 * Submitting a data frame to a specified endpoint of a USB device
 * The frame is put in the driver's transmit queue for this endpoint
 *
 * Arguments:
 * usb          A pointer to the USB structure
 * pkt          A pointer to the user frame structure
 * trans_type   Transaction tyep - IN,OUT or SETUP
 * dest_addr    Device address - 0~127
 * dest_ep      Endpoint number of the device - 0~16
 * trans_mode   Pipe type - ISO,Interrupt,bulk or control
 * dest_speed   USB speed - Low speed or FULL speed
 * data_toggle  Data sequence toggle - 0 or 1
 */
u32 fhci_host_transaction(struct fhci_usb *usb,
			  struct packet *pkt,
			  enum fhci_ta_type trans_type,
			  u8 dest_addr,
			  u8 dest_ep,
			  enum fhci_tf_mode trans_mode,
			  enum fhci_speed dest_speed, u8 data_toggle)
{
	struct endpoint *ep = usb->ep0;
	struct usb_td __iomem *td;
	u16 extra_data;
	u16 td_status;

	fhci_usb_disable_interrupt(usb);
	/* start from the next BD that should be filled */
	td = ep->empty_td;
	td_status = in_be16(&td->status);

	if (td_status & TD_R && in_be16(&td->length)) {
		/* if the TD is not free */
		fhci_usb_enable_interrupt(usb);
		return -1;
	}

	/* get the next TD in the ring */
	ep->empty_td = next_bd(ep->td_base, ep->empty_td, td_status);
	fhci_usb_enable_interrupt(usb);
	pkt->priv_data = td;
	out_be32(&td->buf_ptr, virt_to_phys(pkt->data));
	/* sets up transaction parameters - addr,endp,dir,and type */
	extra_data = (dest_ep << TD_ENDP_SHIFT) | dest_addr;
	switch (trans_type) {
	case FHCI_TA_IN:
		extra_data |= TD_TOK_IN;
		break;
	case FHCI_TA_OUT:
		extra_data |= TD_TOK_OUT;
		break;
	case FHCI_TA_SETUP:
		extra_data |= TD_TOK_SETUP;
		break;
	}
	if (trans_mode == FHCI_TF_ISO)
		extra_data |= TD_ISO;
	out_be16(&td->extra, extra_data);

	/* sets up the buffer descriptor */
	td_status = ((td_status & TD_W) | TD_R | TD_L | TD_I | TD_CNF);
	if (!(pkt->info & PKT_NO_CRC))
		td_status |= TD_TC;

	switch (trans_type) {
	case FHCI_TA_IN:
		if (data_toggle)
			pkt->info |= PKT_PID_DATA1;
		else
			pkt->info |= PKT_PID_DATA0;
		break;
	default:
		if (data_toggle) {
			td_status |= TD_PID_DATA1;
			pkt->info |= PKT_PID_DATA1;
		} else {
			td_status |= TD_PID_DATA0;
			pkt->info |= PKT_PID_DATA0;
		}
		break;
	}

	if ((dest_speed == FHCI_LOW_SPEED) &&
	    (usb->port_status == FHCI_PORT_FULL))
		td_status |= TD_LSP;

	out_be16(&td->status, td_status);

	/* set up buffer length */
	if (trans_type == FHCI_TA_IN)
		out_be16(&td->length, pkt->len + CRC_SIZE);
	else
		out_be16(&td->length, pkt->len);

	/* put the frame to the confirmation queue */
	cq_put(&ep->conf_frame_Q, pkt);

	if (cq_howmany(&ep->conf_frame_Q) == 1)
		out_8(&usb->fhci->regs->usb_comm, USB_CMD_STR_FIFO);

	return 0;
}

/* Reset the Tx BD ring */
void fhci_flush_bds(struct fhci_usb *usb)
{
	u16 extra_data;
	u16 td_status;
	u32 buf;
	struct usb_td __iomem *td;
	struct endpoint *ep = usb->ep0;

	td = ep->td_base;
	while (1) {
		td_status = in_be16(&td->status);
		buf = in_be32(&td->buf_ptr);
		extra_data = in_be16(&td->extra);

		/* if the TD is not empty - we'll confirm it as Timeout */
		if (td_status & TD_R)
			out_be16(&td->status, (td_status & ~TD_R) | TD_TO);
		/* if this TD is dummy - let's skip this TD */
		else if (in_be32(&td->buf_ptr) == DUMMY_BD_BUFFER)
			out_be32(&td->buf_ptr, DUMMY2_BD_BUFFER);
		/* if this is the last TD - break */
		if (td_status & TD_W)
			break;

		td++;
	}

	fhci_td_transaction_confirm(usb);

	td = ep->td_base;
	do {
		out_be16(&td->status, 0);
		out_be16(&td->length, 0);
		out_be32(&td->buf_ptr, 0);
		out_be16(&td->extra, 0);
		td++;
	} while (!(in_be16(&td->status) & TD_W));
	out_be16(&td->status, TD_W); /* for last TD set Wrap bit */
	out_be16(&td->length, 0);
	out_be32(&td->buf_ptr, 0);
	out_be16(&td->extra, 0);

	out_be16(&ep->ep_pram_ptr->tx_bd_ptr,
		 in_be16(&ep->ep_pram_ptr->tx_base));
	out_be32(&ep->ep_pram_ptr->tx_state, 0);
	out_be16(&ep->ep_pram_ptr->tx_cnt, 0);
	ep->empty_td = ep->td_base;
	ep->conf_td = ep->td_base;
}

/*
 * Flush all transmitted packets from TDs in the actual frame.
 * This routine is called when something wrong with the controller and
 * we want to get rid of the actual frame and start again next frame
 */
void fhci_flush_actual_frame(struct fhci_usb *usb)
{
	u8 mode;
	u16 tb_ptr;
	u16 extra_data;
	u16 td_status;
	u32 buf_ptr;
	struct usb_td __iomem *td;
	struct endpoint *ep = usb->ep0;

	/* disable the USB controller */
	mode = in_8(&usb->fhci->regs->usb_mod);
	out_8(&usb->fhci->regs->usb_mod, mode & ~USB_MODE_EN);

	tb_ptr = in_be16(&ep->ep_pram_ptr->tx_bd_ptr);
	td = cpm_muram_addr(tb_ptr);
	td_status = in_be16(&td->status);
	buf_ptr = in_be32(&td->buf_ptr);
	extra_data = in_be16(&td->extra);
	do {
		if (td_status & TD_R) {
			out_be16(&td->status, (td_status & ~TD_R) | TD_TO);
		} else {
			out_be32(&td->buf_ptr, 0);
			ep->already_pushed_dummy_bd = false;
			break;
		}

		/* advance the TD pointer */
		td = next_bd(ep->td_base, td, td_status);
		td_status = in_be16(&td->status);
		buf_ptr = in_be32(&td->buf_ptr);
		extra_data = in_be16(&td->extra);
	} while ((td_status & TD_R) || buf_ptr);

	fhci_td_transaction_confirm(usb);

	out_be16(&ep->ep_pram_ptr->tx_bd_ptr,
		 in_be16(&ep->ep_pram_ptr->tx_base));
	out_be32(&ep->ep_pram_ptr->tx_state, 0);
	out_be16(&ep->ep_pram_ptr->tx_cnt, 0);
	ep->empty_td = ep->td_base;
	ep->conf_td = ep->td_base;

	usb->actual_frame->frame_status = FRAME_TIMER_END_TRANSMISSION;

	/* reset the event register */
	out_be16(&usb->fhci->regs->usb_event, 0xffff);
	/* enable the USB controller */
	out_8(&usb->fhci->regs->usb_mod, mode | USB_MODE_EN);
}

/* handles Tx confirm and Tx error interrupt */
void fhci_tx_conf_interrupt(struct fhci_usb *usb)
{
	fhci_td_transaction_confirm(usb);

	/*
	 * Schedule another transaction to this frame only if we have
	 * already confirmed all transaction in the frame.
	 */
	if (((fhci_get_sof_timer_count(usb) < usb->max_frame_usage) ||
	     (usb->actual_frame->frame_status & FRAME_END_TRANSMISSION)) &&
	    (list_empty(&usb->actual_frame->tds_list)))
		fhci_schedule_transactions(usb);
}

void fhci_host_transmit_actual_frame(struct fhci_usb *usb)
{
	u16 tb_ptr;
	u16 td_status;
	struct usb_td __iomem *td;
	struct endpoint *ep = usb->ep0;

	tb_ptr = in_be16(&ep->ep_pram_ptr->tx_bd_ptr);
	td = cpm_muram_addr(tb_ptr);

	if (in_be32(&td->buf_ptr) == DUMMY_BD_BUFFER) {
		struct usb_td __iomem *old_td = td;

		ep->already_pushed_dummy_bd = false;
		td_status = in_be16(&td->status);
		/* gets the next TD in the ring */
		td = next_bd(ep->td_base, td, td_status);
		tb_ptr = cpm_muram_offset(td);
		out_be16(&ep->ep_pram_ptr->tx_bd_ptr, tb_ptr);

		/* start transmit only if we have something in the TDs */
		if (in_be16(&td->status) & TD_R)
			out_8(&usb->fhci->regs->usb_comm, USB_CMD_STR_FIFO);

		if (in_be32(&ep->conf_td->buf_ptr) == DUMMY_BD_BUFFER) {
			out_be32(&old_td->buf_ptr, 0);
			ep->conf_td = next_bd(ep->td_base, ep->conf_td,
					      td_status);
		} else {
			out_be32(&old_td->buf_ptr, DUMMY2_BD_BUFFER);
		}
	}
}