xref: /rk3399_rockchip-uboot/common/usb.c (revision 676ae068d9af8c4848dc8f3a66d65e2bff066239)
1 /*
2  *
3  * Most of this source has been derived from the Linux USB
4  * project:
5  * (C) Copyright Linus Torvalds 1999
6  * (C) Copyright Johannes Erdfelt 1999-2001
7  * (C) Copyright Andreas Gal 1999
8  * (C) Copyright Gregory P. Smith 1999
9  * (C) Copyright Deti Fliegl 1999 (new USB architecture)
10  * (C) Copyright Randy Dunlap 2000
11  * (C) Copyright David Brownell 2000 (kernel hotplug, usb_device_id)
12  * (C) Copyright Yggdrasil Computing, Inc. 2000
13  *     (usb_device_id matching changes by Adam J. Richter)
14  *
15  * Adapted for U-Boot:
16  * (C) Copyright 2001 Denis Peter, MPL AG Switzerland
17  *
18  * See file CREDITS for list of people who contributed to this
19  * project.
20  *
21  * This program is free software; you can redistribute it and/or
22  * modify it under the terms of the GNU General Public License as
23  * published by the Free Software Foundation; either version 2 of
24  * the License, or (at your option) any later version.
25  *
26  * This program is distributed in the hope that it will be useful,
27  * but WITHOUT ANY WARRANTY; without even the implied warranty of
28  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
29  * GNU General Public License for more details.
30  *
31  * You should have received a copy of the GNU General Public License
32  * along with this program; if not, write to the Free Software
33  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
34  * MA 02111-1307 USA
35  *
36  */
37 
38 /*
39  * How it works:
40  *
41  * Since this is a bootloader, the devices will not be automatic
42  * (re)configured on hotplug, but after a restart of the USB the
43  * device should work.
44  *
45  * For each transfer (except "Interrupt") we wait for completion.
46  */
47 #include <common.h>
48 #include <command.h>
49 #include <asm/processor.h>
50 #include <linux/compiler.h>
51 #include <linux/ctype.h>
52 #include <asm/byteorder.h>
53 #include <asm/unaligned.h>
54 
55 #include <usb.h>
56 #ifdef CONFIG_4xx
57 #include <asm/4xx_pci.h>
58 #endif
59 
60 #ifdef DEBUG
61 #define USB_DEBUG	1
62 #define USB_HUB_DEBUG	1
63 #else
64 #define USB_DEBUG	0
65 #define USB_HUB_DEBUG	0
66 #endif
67 
68 #define USB_PRINTF(fmt, args...)	debug_cond(USB_DEBUG, fmt, ##args)
69 #define USB_HUB_PRINTF(fmt, args...)	debug_cond(USB_HUB_DEBUG, fmt, ##args)
70 
71 #define USB_BUFSIZ	512
72 
73 static struct usb_device usb_dev[USB_MAX_DEVICE];
74 static int dev_index;
75 static int running;
76 static int asynch_allowed;
77 
78 char usb_started; /* flag for the started/stopped USB status */
79 void *ctrl; /* goes away in a following commit, but don't break bisect */
80 
81 /**********************************************************************
82  * some forward declerations...
83  */
84 static void usb_scan_devices(void);
85 
86 /***************************************************************************
87  * Init USB Device
88  */
89 
90 int usb_init(void)
91 {
92 	int result;
93 
94 	running = 0;
95 	dev_index = 0;
96 	asynch_allowed = 1;
97 	usb_hub_reset();
98 	/* init low_level USB */
99 	printf("USB:   ");
100 	result = usb_lowlevel_init(0, &ctrl);
101 	/* if lowlevel init is OK, scan the bus for devices
102 	 * i.e. search HUBs and configure them */
103 	if (result == 0) {
104 		printf("scanning bus for devices... ");
105 		running = 1;
106 		usb_scan_devices();
107 		usb_started = 1;
108 		return 0;
109 	} else {
110 		printf("Error, couldn't init Lowlevel part\n");
111 		usb_started = 0;
112 		return -1;
113 	}
114 }
115 
116 /******************************************************************************
117  * Stop USB this stops the LowLevel Part and deregisters USB devices.
118  */
119 int usb_stop(void)
120 {
121 	int res = 0;
122 
123 	if (usb_started) {
124 		asynch_allowed = 1;
125 		usb_started = 0;
126 		usb_hub_reset();
127 		res = usb_lowlevel_stop(0);
128 	}
129 	return res;
130 }
131 
132 /*
133  * disables the asynch behaviour of the control message. This is used for data
134  * transfers that uses the exclusiv access to the control and bulk messages.
135  * Returns the old value so it can be restored later.
136  */
137 int usb_disable_asynch(int disable)
138 {
139 	int old_value = asynch_allowed;
140 
141 	asynch_allowed = !disable;
142 	return old_value;
143 }
144 
145 
146 /*-------------------------------------------------------------------
147  * Message wrappers.
148  *
149  */
150 
151 /*
152  * submits an Interrupt Message
153  */
154 int usb_submit_int_msg(struct usb_device *dev, unsigned long pipe,
155 			void *buffer, int transfer_len, int interval)
156 {
157 	return submit_int_msg(dev, pipe, buffer, transfer_len, interval);
158 }
159 
160 /*
161  * submits a control message and waits for comletion (at least timeout * 1ms)
162  * If timeout is 0, we don't wait for completion (used as example to set and
163  * clear keyboards LEDs). For data transfers, (storage transfers) we don't
164  * allow control messages with 0 timeout, by previousely resetting the flag
165  * asynch_allowed (usb_disable_asynch(1)).
166  * returns the transfered length if OK or -1 if error. The transfered length
167  * and the current status are stored in the dev->act_len and dev->status.
168  */
169 int usb_control_msg(struct usb_device *dev, unsigned int pipe,
170 			unsigned char request, unsigned char requesttype,
171 			unsigned short value, unsigned short index,
172 			void *data, unsigned short size, int timeout)
173 {
174 	ALLOC_CACHE_ALIGN_BUFFER(struct devrequest, setup_packet, 1);
175 
176 	if ((timeout == 0) && (!asynch_allowed)) {
177 		/* request for a asynch control pipe is not allowed */
178 		return -1;
179 	}
180 
181 	/* set setup command */
182 	setup_packet->requesttype = requesttype;
183 	setup_packet->request = request;
184 	setup_packet->value = cpu_to_le16(value);
185 	setup_packet->index = cpu_to_le16(index);
186 	setup_packet->length = cpu_to_le16(size);
187 	USB_PRINTF("usb_control_msg: request: 0x%X, requesttype: 0x%X, " \
188 		   "value 0x%X index 0x%X length 0x%X\n",
189 		   request, requesttype, value, index, size);
190 	dev->status = USB_ST_NOT_PROC; /*not yet processed */
191 
192 	if (submit_control_msg(dev, pipe, data, size, setup_packet) < 0)
193 		return -1;
194 	if (timeout == 0)
195 		return (int)size;
196 
197 	/*
198 	 * Wait for status to update until timeout expires, USB driver
199 	 * interrupt handler may set the status when the USB operation has
200 	 * been completed.
201 	 */
202 	while (timeout--) {
203 		if (!((volatile unsigned long)dev->status & USB_ST_NOT_PROC))
204 			break;
205 		mdelay(1);
206 	}
207 	if (dev->status)
208 		return -1;
209 
210 	return dev->act_len;
211 
212 }
213 
214 /*-------------------------------------------------------------------
215  * submits bulk message, and waits for completion. returns 0 if Ok or
216  * -1 if Error.
217  * synchronous behavior
218  */
219 int usb_bulk_msg(struct usb_device *dev, unsigned int pipe,
220 			void *data, int len, int *actual_length, int timeout)
221 {
222 	if (len < 0)
223 		return -1;
224 	dev->status = USB_ST_NOT_PROC; /*not yet processed */
225 	if (submit_bulk_msg(dev, pipe, data, len) < 0)
226 		return -1;
227 	while (timeout--) {
228 		if (!((volatile unsigned long)dev->status & USB_ST_NOT_PROC))
229 			break;
230 		mdelay(1);
231 	}
232 	*actual_length = dev->act_len;
233 	if (dev->status == 0)
234 		return 0;
235 	else
236 		return -1;
237 }
238 
239 
240 /*-------------------------------------------------------------------
241  * Max Packet stuff
242  */
243 
244 /*
245  * returns the max packet size, depending on the pipe direction and
246  * the configurations values
247  */
248 int usb_maxpacket(struct usb_device *dev, unsigned long pipe)
249 {
250 	/* direction is out -> use emaxpacket out */
251 	if ((pipe & USB_DIR_IN) == 0)
252 		return dev->epmaxpacketout[((pipe>>15) & 0xf)];
253 	else
254 		return dev->epmaxpacketin[((pipe>>15) & 0xf)];
255 }
256 
257 /*
258  * The routine usb_set_maxpacket_ep() is extracted from the loop of routine
259  * usb_set_maxpacket(), because the optimizer of GCC 4.x chokes on this routine
260  * when it is inlined in 1 single routine. What happens is that the register r3
261  * is used as loop-count 'i', but gets overwritten later on.
262  * This is clearly a compiler bug, but it is easier to workaround it here than
263  * to update the compiler (Occurs with at least several GCC 4.{1,2},x
264  * CodeSourcery compilers like e.g. 2007q3, 2008q1, 2008q3 lite editions on ARM)
265  *
266  * NOTE: Similar behaviour was observed with GCC4.6 on ARMv5.
267  */
268 static void noinline
269 usb_set_maxpacket_ep(struct usb_device *dev, int if_idx, int ep_idx)
270 {
271 	int b;
272 	struct usb_endpoint_descriptor *ep;
273 	u16 ep_wMaxPacketSize;
274 
275 	ep = &dev->config.if_desc[if_idx].ep_desc[ep_idx];
276 
277 	b = ep->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK;
278 	ep_wMaxPacketSize = get_unaligned(&ep->wMaxPacketSize);
279 
280 	if ((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
281 						USB_ENDPOINT_XFER_CONTROL) {
282 		/* Control => bidirectional */
283 		dev->epmaxpacketout[b] = ep_wMaxPacketSize;
284 		dev->epmaxpacketin[b] = ep_wMaxPacketSize;
285 		USB_PRINTF("##Control EP epmaxpacketout/in[%d] = %d\n",
286 			   b, dev->epmaxpacketin[b]);
287 	} else {
288 		if ((ep->bEndpointAddress & 0x80) == 0) {
289 			/* OUT Endpoint */
290 			if (ep_wMaxPacketSize > dev->epmaxpacketout[b]) {
291 				dev->epmaxpacketout[b] = ep_wMaxPacketSize;
292 				USB_PRINTF("##EP epmaxpacketout[%d] = %d\n",
293 					   b, dev->epmaxpacketout[b]);
294 			}
295 		} else {
296 			/* IN Endpoint */
297 			if (ep_wMaxPacketSize > dev->epmaxpacketin[b]) {
298 				dev->epmaxpacketin[b] = ep_wMaxPacketSize;
299 				USB_PRINTF("##EP epmaxpacketin[%d] = %d\n",
300 					   b, dev->epmaxpacketin[b]);
301 			}
302 		} /* if out */
303 	} /* if control */
304 }
305 
306 /*
307  * set the max packed value of all endpoints in the given configuration
308  */
309 static int usb_set_maxpacket(struct usb_device *dev)
310 {
311 	int i, ii;
312 
313 	for (i = 0; i < dev->config.desc.bNumInterfaces; i++)
314 		for (ii = 0; ii < dev->config.if_desc[i].desc.bNumEndpoints; ii++)
315 			usb_set_maxpacket_ep(dev, i, ii);
316 
317 	return 0;
318 }
319 
320 /*******************************************************************************
321  * Parse the config, located in buffer, and fills the dev->config structure.
322  * Note that all little/big endian swapping are done automatically.
323  */
324 static int usb_parse_config(struct usb_device *dev,
325 			unsigned char *buffer, int cfgno)
326 {
327 	struct usb_descriptor_header *head;
328 	int index, ifno, epno, curr_if_num;
329 	int i;
330 	u16 ep_wMaxPacketSize;
331 
332 	ifno = -1;
333 	epno = -1;
334 	curr_if_num = -1;
335 
336 	dev->configno = cfgno;
337 	head = (struct usb_descriptor_header *) &buffer[0];
338 	if (head->bDescriptorType != USB_DT_CONFIG) {
339 		printf(" ERROR: NOT USB_CONFIG_DESC %x\n",
340 			head->bDescriptorType);
341 		return -1;
342 	}
343 	memcpy(&dev->config, buffer, buffer[0]);
344 	le16_to_cpus(&(dev->config.desc.wTotalLength));
345 	dev->config.no_of_if = 0;
346 
347 	index = dev->config.desc.bLength;
348 	/* Ok the first entry must be a configuration entry,
349 	 * now process the others */
350 	head = (struct usb_descriptor_header *) &buffer[index];
351 	while (index + 1 < dev->config.desc.wTotalLength) {
352 		switch (head->bDescriptorType) {
353 		case USB_DT_INTERFACE:
354 			if (((struct usb_interface_descriptor *) \
355 			     &buffer[index])->bInterfaceNumber != curr_if_num) {
356 				/* this is a new interface, copy new desc */
357 				ifno = dev->config.no_of_if;
358 				dev->config.no_of_if++;
359 				memcpy(&dev->config.if_desc[ifno],
360 					&buffer[index], buffer[index]);
361 				dev->config.if_desc[ifno].no_of_ep = 0;
362 				dev->config.if_desc[ifno].num_altsetting = 1;
363 				curr_if_num =
364 				     dev->config.if_desc[ifno].desc.bInterfaceNumber;
365 			} else {
366 				/* found alternate setting for the interface */
367 				dev->config.if_desc[ifno].num_altsetting++;
368 			}
369 			break;
370 		case USB_DT_ENDPOINT:
371 			epno = dev->config.if_desc[ifno].no_of_ep;
372 			/* found an endpoint */
373 			dev->config.if_desc[ifno].no_of_ep++;
374 			memcpy(&dev->config.if_desc[ifno].ep_desc[epno],
375 				&buffer[index], buffer[index]);
376 			ep_wMaxPacketSize = get_unaligned(&dev->config.\
377 							if_desc[ifno].\
378 							ep_desc[epno].\
379 							wMaxPacketSize);
380 			put_unaligned(le16_to_cpu(ep_wMaxPacketSize),
381 					&dev->config.\
382 					if_desc[ifno].\
383 					ep_desc[epno].\
384 					wMaxPacketSize);
385 			USB_PRINTF("if %d, ep %d\n", ifno, epno);
386 			break;
387 		default:
388 			if (head->bLength == 0)
389 				return 1;
390 
391 			USB_PRINTF("unknown Description Type : %x\n",
392 				   head->bDescriptorType);
393 
394 			{
395 #ifdef USB_DEBUG
396 				unsigned char *ch = (unsigned char *)head;
397 #endif
398 				for (i = 0; i < head->bLength; i++)
399 					USB_PRINTF("%02X ", *ch++);
400 				USB_PRINTF("\n\n\n");
401 			}
402 			break;
403 		}
404 		index += head->bLength;
405 		head = (struct usb_descriptor_header *)&buffer[index];
406 	}
407 	return 1;
408 }
409 
410 /***********************************************************************
411  * Clears an endpoint
412  * endp: endpoint number in bits 0-3;
413  * direction flag in bit 7 (1 = IN, 0 = OUT)
414  */
415 int usb_clear_halt(struct usb_device *dev, int pipe)
416 {
417 	int result;
418 	int endp = usb_pipeendpoint(pipe)|(usb_pipein(pipe)<<7);
419 
420 	result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
421 				 USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT, 0,
422 				 endp, NULL, 0, USB_CNTL_TIMEOUT * 3);
423 
424 	/* don't clear if failed */
425 	if (result < 0)
426 		return result;
427 
428 	/*
429 	 * NOTE: we do not get status and verify reset was successful
430 	 * as some devices are reported to lock up upon this check..
431 	 */
432 
433 	usb_endpoint_running(dev, usb_pipeendpoint(pipe), usb_pipeout(pipe));
434 
435 	/* toggle is reset on clear */
436 	usb_settoggle(dev, usb_pipeendpoint(pipe), usb_pipeout(pipe), 0);
437 	return 0;
438 }
439 
440 
441 /**********************************************************************
442  * get_descriptor type
443  */
444 static int usb_get_descriptor(struct usb_device *dev, unsigned char type,
445 			unsigned char index, void *buf, int size)
446 {
447 	int res;
448 	res = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
449 			USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
450 			(type << 8) + index, 0,
451 			buf, size, USB_CNTL_TIMEOUT);
452 	return res;
453 }
454 
455 /**********************************************************************
456  * gets configuration cfgno and store it in the buffer
457  */
458 int usb_get_configuration_no(struct usb_device *dev,
459 			     unsigned char *buffer, int cfgno)
460 {
461 	int result;
462 	unsigned int tmp;
463 	struct usb_configuration_descriptor *config;
464 
465 	config = (struct usb_configuration_descriptor *)&buffer[0];
466 	result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno, buffer, 9);
467 	if (result < 9) {
468 		if (result < 0)
469 			printf("unable to get descriptor, error %lX\n",
470 				dev->status);
471 		else
472 			printf("config descriptor too short " \
473 				"(expected %i, got %i)\n", 9, result);
474 		return -1;
475 	}
476 	tmp = le16_to_cpu(config->wTotalLength);
477 
478 	if (tmp > USB_BUFSIZ) {
479 		USB_PRINTF("usb_get_configuration_no: failed to get " \
480 			   "descriptor - too long: %d\n", tmp);
481 		return -1;
482 	}
483 
484 	result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno, buffer, tmp);
485 	USB_PRINTF("get_conf_no %d Result %d, wLength %d\n",
486 		   cfgno, result, tmp);
487 	return result;
488 }
489 
490 /********************************************************************
491  * set address of a device to the value in dev->devnum.
492  * This can only be done by addressing the device via the default address (0)
493  */
494 static int usb_set_address(struct usb_device *dev)
495 {
496 	int res;
497 
498 	USB_PRINTF("set address %d\n", dev->devnum);
499 	res = usb_control_msg(dev, usb_snddefctrl(dev),
500 				USB_REQ_SET_ADDRESS, 0,
501 				(dev->devnum), 0,
502 				NULL, 0, USB_CNTL_TIMEOUT);
503 	return res;
504 }
505 
506 /********************************************************************
507  * set interface number to interface
508  */
509 int usb_set_interface(struct usb_device *dev, int interface, int alternate)
510 {
511 	struct usb_interface *if_face = NULL;
512 	int ret, i;
513 
514 	for (i = 0; i < dev->config.desc.bNumInterfaces; i++) {
515 		if (dev->config.if_desc[i].desc.bInterfaceNumber == interface) {
516 			if_face = &dev->config.if_desc[i];
517 			break;
518 		}
519 	}
520 	if (!if_face) {
521 		printf("selecting invalid interface %d", interface);
522 		return -1;
523 	}
524 	/*
525 	 * We should return now for devices with only one alternate setting.
526 	 * According to 9.4.10 of the Universal Serial Bus Specification
527 	 * Revision 2.0 such devices can return with a STALL. This results in
528 	 * some USB sticks timeouting during initialization and then being
529 	 * unusable in U-Boot.
530 	 */
531 	if (if_face->num_altsetting == 1)
532 		return 0;
533 
534 	ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
535 				USB_REQ_SET_INTERFACE, USB_RECIP_INTERFACE,
536 				alternate, interface, NULL, 0,
537 				USB_CNTL_TIMEOUT * 5);
538 	if (ret < 0)
539 		return ret;
540 
541 	return 0;
542 }
543 
544 /********************************************************************
545  * set configuration number to configuration
546  */
547 static int usb_set_configuration(struct usb_device *dev, int configuration)
548 {
549 	int res;
550 	USB_PRINTF("set configuration %d\n", configuration);
551 	/* set setup command */
552 	res = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
553 				USB_REQ_SET_CONFIGURATION, 0,
554 				configuration, 0,
555 				NULL, 0, USB_CNTL_TIMEOUT);
556 	if (res == 0) {
557 		dev->toggle[0] = 0;
558 		dev->toggle[1] = 0;
559 		return 0;
560 	} else
561 		return -1;
562 }
563 
564 /********************************************************************
565  * set protocol to protocol
566  */
567 int usb_set_protocol(struct usb_device *dev, int ifnum, int protocol)
568 {
569 	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
570 		USB_REQ_SET_PROTOCOL, USB_TYPE_CLASS | USB_RECIP_INTERFACE,
571 		protocol, ifnum, NULL, 0, USB_CNTL_TIMEOUT);
572 }
573 
574 /********************************************************************
575  * set idle
576  */
577 int usb_set_idle(struct usb_device *dev, int ifnum, int duration, int report_id)
578 {
579 	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
580 		USB_REQ_SET_IDLE, USB_TYPE_CLASS | USB_RECIP_INTERFACE,
581 		(duration << 8) | report_id, ifnum, NULL, 0, USB_CNTL_TIMEOUT);
582 }
583 
584 /********************************************************************
585  * get report
586  */
587 int usb_get_report(struct usb_device *dev, int ifnum, unsigned char type,
588 		   unsigned char id, void *buf, int size)
589 {
590 	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
591 			USB_REQ_GET_REPORT,
592 			USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
593 			(type << 8) + id, ifnum, buf, size, USB_CNTL_TIMEOUT);
594 }
595 
596 /********************************************************************
597  * get class descriptor
598  */
599 int usb_get_class_descriptor(struct usb_device *dev, int ifnum,
600 		unsigned char type, unsigned char id, void *buf, int size)
601 {
602 	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
603 		USB_REQ_GET_DESCRIPTOR, USB_RECIP_INTERFACE | USB_DIR_IN,
604 		(type << 8) + id, ifnum, buf, size, USB_CNTL_TIMEOUT);
605 }
606 
607 /********************************************************************
608  * get string index in buffer
609  */
610 static int usb_get_string(struct usb_device *dev, unsigned short langid,
611 		   unsigned char index, void *buf, int size)
612 {
613 	int i;
614 	int result;
615 
616 	for (i = 0; i < 3; ++i) {
617 		/* some devices are flaky */
618 		result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
619 			USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
620 			(USB_DT_STRING << 8) + index, langid, buf, size,
621 			USB_CNTL_TIMEOUT);
622 
623 		if (result > 0)
624 			break;
625 	}
626 
627 	return result;
628 }
629 
630 
631 static void usb_try_string_workarounds(unsigned char *buf, int *length)
632 {
633 	int newlength, oldlength = *length;
634 
635 	for (newlength = 2; newlength + 1 < oldlength; newlength += 2)
636 		if (!isprint(buf[newlength]) || buf[newlength + 1])
637 			break;
638 
639 	if (newlength > 2) {
640 		buf[0] = newlength;
641 		*length = newlength;
642 	}
643 }
644 
645 
646 static int usb_string_sub(struct usb_device *dev, unsigned int langid,
647 		unsigned int index, unsigned char *buf)
648 {
649 	int rc;
650 
651 	/* Try to read the string descriptor by asking for the maximum
652 	 * possible number of bytes */
653 	rc = usb_get_string(dev, langid, index, buf, 255);
654 
655 	/* If that failed try to read the descriptor length, then
656 	 * ask for just that many bytes */
657 	if (rc < 2) {
658 		rc = usb_get_string(dev, langid, index, buf, 2);
659 		if (rc == 2)
660 			rc = usb_get_string(dev, langid, index, buf, buf[0]);
661 	}
662 
663 	if (rc >= 2) {
664 		if (!buf[0] && !buf[1])
665 			usb_try_string_workarounds(buf, &rc);
666 
667 		/* There might be extra junk at the end of the descriptor */
668 		if (buf[0] < rc)
669 			rc = buf[0];
670 
671 		rc = rc - (rc & 1); /* force a multiple of two */
672 	}
673 
674 	if (rc < 2)
675 		rc = -1;
676 
677 	return rc;
678 }
679 
680 
681 /********************************************************************
682  * usb_string:
683  * Get string index and translate it to ascii.
684  * returns string length (> 0) or error (< 0)
685  */
686 int usb_string(struct usb_device *dev, int index, char *buf, size_t size)
687 {
688 	ALLOC_CACHE_ALIGN_BUFFER(unsigned char, mybuf, USB_BUFSIZ);
689 	unsigned char *tbuf;
690 	int err;
691 	unsigned int u, idx;
692 
693 	if (size <= 0 || !buf || !index)
694 		return -1;
695 	buf[0] = 0;
696 	tbuf = &mybuf[0];
697 
698 	/* get langid for strings if it's not yet known */
699 	if (!dev->have_langid) {
700 		err = usb_string_sub(dev, 0, 0, tbuf);
701 		if (err < 0) {
702 			USB_PRINTF("error getting string descriptor 0 " \
703 				   "(error=%lx)\n", dev->status);
704 			return -1;
705 		} else if (tbuf[0] < 4) {
706 			USB_PRINTF("string descriptor 0 too short\n");
707 			return -1;
708 		} else {
709 			dev->have_langid = -1;
710 			dev->string_langid = tbuf[2] | (tbuf[3] << 8);
711 				/* always use the first langid listed */
712 			USB_PRINTF("USB device number %d default " \
713 				   "language ID 0x%x\n",
714 				   dev->devnum, dev->string_langid);
715 		}
716 	}
717 
718 	err = usb_string_sub(dev, dev->string_langid, index, tbuf);
719 	if (err < 0)
720 		return err;
721 
722 	size--;		/* leave room for trailing NULL char in output buffer */
723 	for (idx = 0, u = 2; u < err; u += 2) {
724 		if (idx >= size)
725 			break;
726 		if (tbuf[u+1])			/* high byte */
727 			buf[idx++] = '?';  /* non-ASCII character */
728 		else
729 			buf[idx++] = tbuf[u];
730 	}
731 	buf[idx] = 0;
732 	err = idx;
733 	return err;
734 }
735 
736 
737 /********************************************************************
738  * USB device handling:
739  * the USB device are static allocated [USB_MAX_DEVICE].
740  */
741 
742 
743 /* returns a pointer to the device with the index [index].
744  * if the device is not assigned (dev->devnum==-1) returns NULL
745  */
746 struct usb_device *usb_get_dev_index(int index)
747 {
748 	if (usb_dev[index].devnum == -1)
749 		return NULL;
750 	else
751 		return &usb_dev[index];
752 }
753 
754 
755 /* returns a pointer of a new device structure or NULL, if
756  * no device struct is available
757  */
758 struct usb_device *usb_alloc_new_device(void *controller)
759 {
760 	int i;
761 	USB_PRINTF("New Device %d\n", dev_index);
762 	if (dev_index == USB_MAX_DEVICE) {
763 		printf("ERROR, too many USB Devices, max=%d\n", USB_MAX_DEVICE);
764 		return NULL;
765 	}
766 	/* default Address is 0, real addresses start with 1 */
767 	usb_dev[dev_index].devnum = dev_index + 1;
768 	usb_dev[dev_index].maxchild = 0;
769 	for (i = 0; i < USB_MAXCHILDREN; i++)
770 		usb_dev[dev_index].children[i] = NULL;
771 	usb_dev[dev_index].parent = NULL;
772 	usb_dev[dev_index].controller = controller;
773 	dev_index++;
774 	return &usb_dev[dev_index - 1];
775 }
776 
777 
778 /*
779  * By the time we get here, the device has gotten a new device ID
780  * and is in the default state. We need to identify the thing and
781  * get the ball rolling..
782  *
783  * Returns 0 for success, != 0 for error.
784  */
785 int usb_new_device(struct usb_device *dev)
786 {
787 	int addr, err;
788 	int tmp;
789 	ALLOC_CACHE_ALIGN_BUFFER(unsigned char, tmpbuf, USB_BUFSIZ);
790 
791 	/* We still haven't set the Address yet */
792 	addr = dev->devnum;
793 	dev->devnum = 0;
794 
795 #ifdef CONFIG_LEGACY_USB_INIT_SEQ
796 	/* this is the old and known way of initializing devices, it is
797 	 * different than what Windows and Linux are doing. Windows and Linux
798 	 * both retrieve 64 bytes while reading the device descriptor
799 	 * Several USB stick devices report ERR: CTL_TIMEOUT, caused by an
800 	 * invalid header while reading 8 bytes as device descriptor. */
801 	dev->descriptor.bMaxPacketSize0 = 8;	    /* Start off at 8 bytes  */
802 	dev->maxpacketsize = PACKET_SIZE_8;
803 	dev->epmaxpacketin[0] = 8;
804 	dev->epmaxpacketout[0] = 8;
805 
806 	err = usb_get_descriptor(dev, USB_DT_DEVICE, 0, tmpbuf, 8);
807 	if (err < 8) {
808 		printf("\n      USB device not responding, " \
809 		       "giving up (status=%lX)\n", dev->status);
810 		return 1;
811 	}
812 	memcpy(&dev->descriptor, tmpbuf, 8);
813 #else
814 	/* This is a Windows scheme of initialization sequence, with double
815 	 * reset of the device (Linux uses the same sequence)
816 	 * Some equipment is said to work only with such init sequence; this
817 	 * patch is based on the work by Alan Stern:
818 	 * http://sourceforge.net/mailarchive/forum.php?
819 	 * thread_id=5729457&forum_id=5398
820 	 */
821 	struct usb_device_descriptor *desc;
822 	int port = -1;
823 	struct usb_device *parent = dev->parent;
824 	unsigned short portstatus;
825 
826 	/* send 64-byte GET-DEVICE-DESCRIPTOR request.  Since the descriptor is
827 	 * only 18 bytes long, this will terminate with a short packet.  But if
828 	 * the maxpacket size is 8 or 16 the device may be waiting to transmit
829 	 * some more, or keeps on retransmitting the 8 byte header. */
830 
831 	desc = (struct usb_device_descriptor *)tmpbuf;
832 	dev->descriptor.bMaxPacketSize0 = 64;	    /* Start off at 64 bytes  */
833 	/* Default to 64 byte max packet size */
834 	dev->maxpacketsize = PACKET_SIZE_64;
835 	dev->epmaxpacketin[0] = 64;
836 	dev->epmaxpacketout[0] = 64;
837 
838 	err = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, 64);
839 	if (err < 0) {
840 		USB_PRINTF("usb_new_device: usb_get_descriptor() failed\n");
841 		return 1;
842 	}
843 
844 	dev->descriptor.bMaxPacketSize0 = desc->bMaxPacketSize0;
845 
846 	/* find the port number we're at */
847 	if (parent) {
848 		int j;
849 
850 		for (j = 0; j < parent->maxchild; j++) {
851 			if (parent->children[j] == dev) {
852 				port = j;
853 				break;
854 			}
855 		}
856 		if (port < 0) {
857 			printf("usb_new_device:cannot locate device's port.\n");
858 			return 1;
859 		}
860 
861 		/* reset the port for the second time */
862 		err = hub_port_reset(dev->parent, port, &portstatus);
863 		if (err < 0) {
864 			printf("\n     Couldn't reset port %i\n", port);
865 			return 1;
866 		}
867 	}
868 #endif
869 
870 	dev->epmaxpacketin[0] = dev->descriptor.bMaxPacketSize0;
871 	dev->epmaxpacketout[0] = dev->descriptor.bMaxPacketSize0;
872 	switch (dev->descriptor.bMaxPacketSize0) {
873 	case 8:
874 		dev->maxpacketsize  = PACKET_SIZE_8;
875 		break;
876 	case 16:
877 		dev->maxpacketsize = PACKET_SIZE_16;
878 		break;
879 	case 32:
880 		dev->maxpacketsize = PACKET_SIZE_32;
881 		break;
882 	case 64:
883 		dev->maxpacketsize = PACKET_SIZE_64;
884 		break;
885 	}
886 	dev->devnum = addr;
887 
888 	err = usb_set_address(dev); /* set address */
889 
890 	if (err < 0) {
891 		printf("\n      USB device not accepting new address " \
892 			"(error=%lX)\n", dev->status);
893 		return 1;
894 	}
895 
896 	mdelay(10);	/* Let the SET_ADDRESS settle */
897 
898 	tmp = sizeof(dev->descriptor);
899 
900 	err = usb_get_descriptor(dev, USB_DT_DEVICE, 0,
901 				 tmpbuf, sizeof(dev->descriptor));
902 	if (err < tmp) {
903 		if (err < 0)
904 			printf("unable to get device descriptor (error=%d)\n",
905 			       err);
906 		else
907 			printf("USB device descriptor short read " \
908 				"(expected %i, got %i)\n", tmp, err);
909 		return 1;
910 	}
911 	memcpy(&dev->descriptor, tmpbuf, sizeof(dev->descriptor));
912 	/* correct le values */
913 	le16_to_cpus(&dev->descriptor.bcdUSB);
914 	le16_to_cpus(&dev->descriptor.idVendor);
915 	le16_to_cpus(&dev->descriptor.idProduct);
916 	le16_to_cpus(&dev->descriptor.bcdDevice);
917 	/* only support for one config for now */
918 	usb_get_configuration_no(dev, tmpbuf, 0);
919 	usb_parse_config(dev, tmpbuf, 0);
920 	usb_set_maxpacket(dev);
921 	/* we set the default configuration here */
922 	if (usb_set_configuration(dev, dev->config.desc.bConfigurationValue)) {
923 		printf("failed to set default configuration " \
924 			"len %d, status %lX\n", dev->act_len, dev->status);
925 		return -1;
926 	}
927 	USB_PRINTF("new device strings: Mfr=%d, Product=%d, SerialNumber=%d\n",
928 		   dev->descriptor.iManufacturer, dev->descriptor.iProduct,
929 		   dev->descriptor.iSerialNumber);
930 	memset(dev->mf, 0, sizeof(dev->mf));
931 	memset(dev->prod, 0, sizeof(dev->prod));
932 	memset(dev->serial, 0, sizeof(dev->serial));
933 	if (dev->descriptor.iManufacturer)
934 		usb_string(dev, dev->descriptor.iManufacturer,
935 			   dev->mf, sizeof(dev->mf));
936 	if (dev->descriptor.iProduct)
937 		usb_string(dev, dev->descriptor.iProduct,
938 			   dev->prod, sizeof(dev->prod));
939 	if (dev->descriptor.iSerialNumber)
940 		usb_string(dev, dev->descriptor.iSerialNumber,
941 			   dev->serial, sizeof(dev->serial));
942 	USB_PRINTF("Manufacturer %s\n", dev->mf);
943 	USB_PRINTF("Product      %s\n", dev->prod);
944 	USB_PRINTF("SerialNumber %s\n", dev->serial);
945 	/* now prode if the device is a hub */
946 	usb_hub_probe(dev, 0);
947 	return 0;
948 }
949 
950 /* build device Tree  */
951 static void usb_scan_devices(void)
952 {
953 	int i;
954 	struct usb_device *dev;
955 
956 	/* first make all devices unknown */
957 	for (i = 0; i < USB_MAX_DEVICE; i++) {
958 		memset(&usb_dev[i], 0, sizeof(struct usb_device));
959 		usb_dev[i].devnum = -1;
960 	}
961 	dev_index = 0;
962 	/* device 0 is always present (root hub, so let it analyze) */
963 	dev = usb_alloc_new_device(ctrl);
964 	if (usb_new_device(dev))
965 		printf("No USB Device found\n");
966 	else
967 		printf("%d USB Device(s) found\n", dev_index);
968 	/* insert "driver" if possible */
969 #ifdef CONFIG_USB_KEYBOARD
970 	drv_usb_kbd_init();
971 #endif
972 	USB_PRINTF("scan end\n");
973 }
974 
975 /* EOF */
976