xref: /linux/drivers/usb/early/ehci-dbgp.c (revision e26207a3819684e9b4450a2d30bdd065fa92d9c7)
1 /*
2  * Standalone EHCI usb debug driver
3  *
4  * Originally written by:
5  *  Eric W. Biederman" <ebiederm@xmission.com> and
6  *  Yinghai Lu <yhlu.kernel@gmail.com>
7  *
8  * Changes for early/late printk and HW errata:
9  *  Jason Wessel <jason.wessel@windriver.com>
10  *  Copyright (C) 2009 Wind River Systems, Inc.
11  *
12  */
13 
14 #include <linux/console.h>
15 #include <linux/errno.h>
16 #include <linux/module.h>
17 #include <linux/pci_regs.h>
18 #include <linux/pci_ids.h>
19 #include <linux/usb/ch9.h>
20 #include <linux/usb/ehci_def.h>
21 #include <linux/delay.h>
22 #include <asm/io.h>
23 #include <asm/pci-direct.h>
24 #include <asm/fixmap.h>
25 
26 /* The code here is intended to talk directly to the EHCI debug port
27  * and does not require that you have any kind of USB host controller
28  * drivers or USB device drivers compiled into the kernel.
29  *
30  * If you make a change to anything in here, the following test cases
31  * need to pass where a USB debug device works in the following
32  * configurations.
33  *
34  * 1. boot args:  earlyprintk=dbgp
35  *     o kernel compiled with # CONFIG_USB_EHCI_HCD is not set
36  *     o kernel compiled with CONFIG_USB_EHCI_HCD=y
37  * 2. boot args: earlyprintk=dbgp,keep
38  *     o kernel compiled with # CONFIG_USB_EHCI_HCD is not set
39  *     o kernel compiled with CONFIG_USB_EHCI_HCD=y
40  * 3. boot args: earlyprintk=dbgp console=ttyUSB0
41  *     o kernel has CONFIG_USB_EHCI_HCD=y and
42  *       CONFIG_USB_SERIAL_DEBUG=y
43  * 4. boot args: earlyprintk=vga,dbgp
44  *     o kernel compiled with # CONFIG_USB_EHCI_HCD is not set
45  *     o kernel compiled with CONFIG_USB_EHCI_HCD=y
46  *
47  * For the 4th configuration you can turn on or off the DBGP_DEBUG
48  * such that you can debug the dbgp device's driver code.
49  */
50 
51 static int dbgp_phys_port = 1;
52 
53 static struct ehci_caps __iomem *ehci_caps;
54 static struct ehci_regs __iomem *ehci_regs;
55 static struct ehci_dbg_port __iomem *ehci_debug;
56 static int dbgp_not_safe; /* Cannot use debug device during ehci reset */
57 static unsigned int dbgp_endpoint_out;
58 
59 struct ehci_dev {
60 	u32 bus;
61 	u32 slot;
62 	u32 func;
63 };
64 
65 static struct ehci_dev ehci_dev;
66 
67 #define USB_DEBUG_DEVNUM 127
68 
69 #define DBGP_DATA_TOGGLE	0x8800
70 
71 #ifdef DBGP_DEBUG
72 #define dbgp_printk printk
73 static void dbgp_ehci_status(char *str)
74 {
75 	if (!ehci_debug)
76 		return;
77 	dbgp_printk("dbgp: %s\n", str);
78 	dbgp_printk("  Debug control: %08x", readl(&ehci_debug->control));
79 	dbgp_printk("  ehci cmd     : %08x", readl(&ehci_regs->command));
80 	dbgp_printk("  ehci conf flg: %08x\n",
81 		    readl(&ehci_regs->configured_flag));
82 	dbgp_printk("  ehci status  : %08x", readl(&ehci_regs->status));
83 	dbgp_printk("  ehci portsc  : %08x\n",
84 		    readl(&ehci_regs->port_status[dbgp_phys_port - 1]));
85 }
86 #else
87 static inline void dbgp_ehci_status(char *str) { }
88 static inline void dbgp_printk(const char *fmt, ...) { }
89 #endif
90 
91 static inline u32 dbgp_pid_update(u32 x, u32 tok)
92 {
93 	return ((x ^ DBGP_DATA_TOGGLE) & 0xffff00) | (tok & 0xff);
94 }
95 
96 static inline u32 dbgp_len_update(u32 x, u32 len)
97 {
98 	return (x & ~0x0f) | (len & 0x0f);
99 }
100 
101 /*
102  * USB Packet IDs (PIDs)
103  */
104 
105 /* token */
106 #define USB_PID_OUT		0xe1
107 #define USB_PID_IN		0x69
108 #define USB_PID_SOF		0xa5
109 #define USB_PID_SETUP		0x2d
110 /* handshake */
111 #define USB_PID_ACK		0xd2
112 #define USB_PID_NAK		0x5a
113 #define USB_PID_STALL		0x1e
114 #define USB_PID_NYET		0x96
115 /* data */
116 #define USB_PID_DATA0		0xc3
117 #define USB_PID_DATA1		0x4b
118 #define USB_PID_DATA2		0x87
119 #define USB_PID_MDATA		0x0f
120 /* Special */
121 #define USB_PID_PREAMBLE	0x3c
122 #define USB_PID_ERR		0x3c
123 #define USB_PID_SPLIT		0x78
124 #define USB_PID_PING		0xb4
125 #define USB_PID_UNDEF_0		0xf0
126 
127 #define USB_PID_DATA_TOGGLE	0x88
128 #define DBGP_CLAIM (DBGP_OWNER | DBGP_ENABLED | DBGP_INUSE)
129 
130 #define PCI_CAP_ID_EHCI_DEBUG	0xa
131 
132 #define HUB_ROOT_RESET_TIME	50	/* times are in msec */
133 #define HUB_SHORT_RESET_TIME	10
134 #define HUB_LONG_RESET_TIME	200
135 #define HUB_RESET_TIMEOUT	500
136 
137 #define DBGP_MAX_PACKET		8
138 #define DBGP_TIMEOUT		(250 * 1000)
139 
140 static int dbgp_wait_until_complete(void)
141 {
142 	u32 ctrl;
143 	int loop = DBGP_TIMEOUT;
144 
145 	do {
146 		ctrl = readl(&ehci_debug->control);
147 		/* Stop when the transaction is finished */
148 		if (ctrl & DBGP_DONE)
149 			break;
150 		udelay(1);
151 	} while (--loop > 0);
152 
153 	if (!loop)
154 		return -DBGP_TIMEOUT;
155 
156 	/*
157 	 * Now that we have observed the completed transaction,
158 	 * clear the done bit.
159 	 */
160 	writel(ctrl | DBGP_DONE, &ehci_debug->control);
161 	return (ctrl & DBGP_ERROR) ? -DBGP_ERRCODE(ctrl) : DBGP_LEN(ctrl);
162 }
163 
164 static inline void dbgp_mdelay(int ms)
165 {
166 	int i;
167 
168 	while (ms--) {
169 		for (i = 0; i < 1000; i++)
170 			outb(0x1, 0x80);
171 	}
172 }
173 
174 static void dbgp_breath(void)
175 {
176 	/* Sleep to give the debug port a chance to breathe */
177 }
178 
179 static int dbgp_wait_until_done(unsigned ctrl)
180 {
181 	u32 pids, lpid;
182 	int ret;
183 	int loop = 3;
184 
185 retry:
186 	writel(ctrl | DBGP_GO, &ehci_debug->control);
187 	ret = dbgp_wait_until_complete();
188 	pids = readl(&ehci_debug->pids);
189 	lpid = DBGP_PID_GET(pids);
190 
191 	if (ret < 0) {
192 		/* A -DBGP_TIMEOUT failure here means the device has
193 		 * failed, perhaps because it was unplugged, in which
194 		 * case we do not want to hang the system so the dbgp
195 		 * will be marked as unsafe to use.  EHCI reset is the
196 		 * only way to recover if you unplug the dbgp device.
197 		 */
198 		if (ret == -DBGP_TIMEOUT && !dbgp_not_safe)
199 			dbgp_not_safe = 1;
200 		return ret;
201 	}
202 
203 	/*
204 	 * If the port is getting full or it has dropped data
205 	 * start pacing ourselves, not necessary but it's friendly.
206 	 */
207 	if ((lpid == USB_PID_NAK) || (lpid == USB_PID_NYET))
208 		dbgp_breath();
209 
210 	/* If I get a NACK reissue the transmission */
211 	if (lpid == USB_PID_NAK) {
212 		if (--loop > 0)
213 			goto retry;
214 	}
215 
216 	return ret;
217 }
218 
219 static inline void dbgp_set_data(const void *buf, int size)
220 {
221 	const unsigned char *bytes = buf;
222 	u32 lo, hi;
223 	int i;
224 
225 	lo = hi = 0;
226 	for (i = 0; i < 4 && i < size; i++)
227 		lo |= bytes[i] << (8*i);
228 	for (; i < 8 && i < size; i++)
229 		hi |= bytes[i] << (8*(i - 4));
230 	writel(lo, &ehci_debug->data03);
231 	writel(hi, &ehci_debug->data47);
232 }
233 
234 static inline void dbgp_get_data(void *buf, int size)
235 {
236 	unsigned char *bytes = buf;
237 	u32 lo, hi;
238 	int i;
239 
240 	lo = readl(&ehci_debug->data03);
241 	hi = readl(&ehci_debug->data47);
242 	for (i = 0; i < 4 && i < size; i++)
243 		bytes[i] = (lo >> (8*i)) & 0xff;
244 	for (; i < 8 && i < size; i++)
245 		bytes[i] = (hi >> (8*(i - 4))) & 0xff;
246 }
247 
248 static int dbgp_out(u32 addr, const char *bytes, int size)
249 {
250 	u32 pids, ctrl;
251 
252 	pids = readl(&ehci_debug->pids);
253 	pids = dbgp_pid_update(pids, USB_PID_OUT);
254 
255 	ctrl = readl(&ehci_debug->control);
256 	ctrl = dbgp_len_update(ctrl, size);
257 	ctrl |= DBGP_OUT;
258 	ctrl |= DBGP_GO;
259 
260 	dbgp_set_data(bytes, size);
261 	writel(addr, &ehci_debug->address);
262 	writel(pids, &ehci_debug->pids);
263 	return dbgp_wait_until_done(ctrl);
264 }
265 
266 static int dbgp_bulk_write(unsigned devnum, unsigned endpoint,
267 			 const char *bytes, int size)
268 {
269 	int ret;
270 	int loops = 5;
271 	u32 addr;
272 	if (size > DBGP_MAX_PACKET)
273 		return -1;
274 
275 	addr = DBGP_EPADDR(devnum, endpoint);
276 try_again:
277 	if (loops--) {
278 		ret = dbgp_out(addr, bytes, size);
279 		if (ret == -DBGP_ERR_BAD) {
280 			int try_loops = 3;
281 			do {
282 				/* Emit a dummy packet to re-sync communication
283 				 * with the debug device */
284 				if (dbgp_out(addr, "12345678", 8) >= 0) {
285 					udelay(2);
286 					goto try_again;
287 				}
288 			} while (try_loops--);
289 		}
290 	}
291 
292 	return ret;
293 }
294 
295 static int dbgp_bulk_read(unsigned devnum, unsigned endpoint, void *data,
296 				 int size)
297 {
298 	u32 pids, addr, ctrl;
299 	int ret;
300 
301 	if (size > DBGP_MAX_PACKET)
302 		return -1;
303 
304 	addr = DBGP_EPADDR(devnum, endpoint);
305 
306 	pids = readl(&ehci_debug->pids);
307 	pids = dbgp_pid_update(pids, USB_PID_IN);
308 
309 	ctrl = readl(&ehci_debug->control);
310 	ctrl = dbgp_len_update(ctrl, size);
311 	ctrl &= ~DBGP_OUT;
312 	ctrl |= DBGP_GO;
313 
314 	writel(addr, &ehci_debug->address);
315 	writel(pids, &ehci_debug->pids);
316 	ret = dbgp_wait_until_done(ctrl);
317 	if (ret < 0)
318 		return ret;
319 
320 	if (size > ret)
321 		size = ret;
322 	dbgp_get_data(data, size);
323 	return ret;
324 }
325 
326 static int dbgp_control_msg(unsigned devnum, int requesttype,
327 	int request, int value, int index, void *data, int size)
328 {
329 	u32 pids, addr, ctrl;
330 	struct usb_ctrlrequest req;
331 	int read;
332 	int ret;
333 
334 	read = (requesttype & USB_DIR_IN) != 0;
335 	if (size > (read ? DBGP_MAX_PACKET:0))
336 		return -1;
337 
338 	/* Compute the control message */
339 	req.bRequestType = requesttype;
340 	req.bRequest = request;
341 	req.wValue = cpu_to_le16(value);
342 	req.wIndex = cpu_to_le16(index);
343 	req.wLength = cpu_to_le16(size);
344 
345 	pids = DBGP_PID_SET(USB_PID_DATA0, USB_PID_SETUP);
346 	addr = DBGP_EPADDR(devnum, 0);
347 
348 	ctrl = readl(&ehci_debug->control);
349 	ctrl = dbgp_len_update(ctrl, sizeof(req));
350 	ctrl |= DBGP_OUT;
351 	ctrl |= DBGP_GO;
352 
353 	/* Send the setup message */
354 	dbgp_set_data(&req, sizeof(req));
355 	writel(addr, &ehci_debug->address);
356 	writel(pids, &ehci_debug->pids);
357 	ret = dbgp_wait_until_done(ctrl);
358 	if (ret < 0)
359 		return ret;
360 
361 	/* Read the result */
362 	return dbgp_bulk_read(devnum, 0, data, size);
363 }
364 
365 
366 /* Find a PCI capability */
367 static u32 __init find_cap(u32 num, u32 slot, u32 func, int cap)
368 {
369 	u8 pos;
370 	int bytes;
371 
372 	if (!(read_pci_config_16(num, slot, func, PCI_STATUS) &
373 		PCI_STATUS_CAP_LIST))
374 		return 0;
375 
376 	pos = read_pci_config_byte(num, slot, func, PCI_CAPABILITY_LIST);
377 	for (bytes = 0; bytes < 48 && pos >= 0x40; bytes++) {
378 		u8 id;
379 
380 		pos &= ~3;
381 		id = read_pci_config_byte(num, slot, func, pos+PCI_CAP_LIST_ID);
382 		if (id == 0xff)
383 			break;
384 		if (id == cap)
385 			return pos;
386 
387 		pos = read_pci_config_byte(num, slot, func,
388 						 pos+PCI_CAP_LIST_NEXT);
389 	}
390 	return 0;
391 }
392 
393 static u32 __init __find_dbgp(u32 bus, u32 slot, u32 func)
394 {
395 	u32 class;
396 
397 	class = read_pci_config(bus, slot, func, PCI_CLASS_REVISION);
398 	if ((class >> 8) != PCI_CLASS_SERIAL_USB_EHCI)
399 		return 0;
400 
401 	return find_cap(bus, slot, func, PCI_CAP_ID_EHCI_DEBUG);
402 }
403 
404 static u32 __init find_dbgp(int ehci_num, u32 *rbus, u32 *rslot, u32 *rfunc)
405 {
406 	u32 bus, slot, func;
407 
408 	for (bus = 0; bus < 256; bus++) {
409 		for (slot = 0; slot < 32; slot++) {
410 			for (func = 0; func < 8; func++) {
411 				unsigned cap;
412 
413 				cap = __find_dbgp(bus, slot, func);
414 
415 				if (!cap)
416 					continue;
417 				if (ehci_num-- != 0)
418 					continue;
419 				*rbus = bus;
420 				*rslot = slot;
421 				*rfunc = func;
422 				return cap;
423 			}
424 		}
425 	}
426 	return 0;
427 }
428 
429 static int dbgp_ehci_startup(void)
430 {
431 	u32 ctrl, cmd, status;
432 	int loop;
433 
434 	/* Claim ownership, but do not enable yet */
435 	ctrl = readl(&ehci_debug->control);
436 	ctrl |= DBGP_OWNER;
437 	ctrl &= ~(DBGP_ENABLED | DBGP_INUSE);
438 	writel(ctrl, &ehci_debug->control);
439 	udelay(1);
440 
441 	dbgp_ehci_status("EHCI startup");
442 	/* Start the ehci running */
443 	cmd = readl(&ehci_regs->command);
444 	cmd &= ~(CMD_LRESET | CMD_IAAD | CMD_PSE | CMD_ASE | CMD_RESET);
445 	cmd |= CMD_RUN;
446 	writel(cmd, &ehci_regs->command);
447 
448 	/* Ensure everything is routed to the EHCI */
449 	writel(FLAG_CF, &ehci_regs->configured_flag);
450 
451 	/* Wait until the controller is no longer halted */
452 	loop = 10;
453 	do {
454 		status = readl(&ehci_regs->status);
455 		if (!(status & STS_HALT))
456 			break;
457 		udelay(1);
458 	} while (--loop > 0);
459 
460 	if (!loop) {
461 		dbgp_printk("ehci can not be started\n");
462 		return -ENODEV;
463 	}
464 	dbgp_printk("ehci started\n");
465 	return 0;
466 }
467 
468 static int dbgp_ehci_controller_reset(void)
469 {
470 	int loop = 250 * 1000;
471 	u32 cmd;
472 
473 	/* Reset the EHCI controller */
474 	cmd = readl(&ehci_regs->command);
475 	cmd |= CMD_RESET;
476 	writel(cmd, &ehci_regs->command);
477 	do {
478 		cmd = readl(&ehci_regs->command);
479 	} while ((cmd & CMD_RESET) && (--loop > 0));
480 
481 	if (!loop) {
482 		dbgp_printk("can not reset ehci\n");
483 		return -1;
484 	}
485 	dbgp_ehci_status("ehci reset done");
486 	return 0;
487 }
488 static int ehci_wait_for_port(int port);
489 /* Return 0 on success
490  * Return -ENODEV for any general failure
491  * Return -EIO if wait for port fails
492  */
493 int dbgp_external_startup(void)
494 {
495 	int devnum;
496 	struct usb_debug_descriptor dbgp_desc;
497 	int ret;
498 	u32 ctrl, portsc, cmd;
499 	int dbg_port = dbgp_phys_port;
500 	int tries = 3;
501 	int reset_port_tries = 1;
502 	int try_hard_once = 1;
503 
504 try_port_reset_again:
505 	ret = dbgp_ehci_startup();
506 	if (ret)
507 		return ret;
508 
509 	/* Wait for a device to show up in the debug port */
510 	ret = ehci_wait_for_port(dbg_port);
511 	if (ret < 0) {
512 		portsc = readl(&ehci_regs->port_status[dbg_port - 1]);
513 		if (!(portsc & PORT_CONNECT) && try_hard_once) {
514 			/* Last ditch effort to try to force enable
515 			 * the debug device by using the packet test
516 			 * ehci command to try and wake it up. */
517 			try_hard_once = 0;
518 			cmd = readl(&ehci_regs->command);
519 			cmd &= ~CMD_RUN;
520 			writel(cmd, &ehci_regs->command);
521 			portsc = readl(&ehci_regs->port_status[dbg_port - 1]);
522 			portsc |= PORT_TEST_PKT;
523 			writel(portsc, &ehci_regs->port_status[dbg_port - 1]);
524 			dbgp_ehci_status("Trying to force debug port online");
525 			mdelay(50);
526 			dbgp_ehci_controller_reset();
527 			goto try_port_reset_again;
528 		} else if (reset_port_tries--) {
529 			goto try_port_reset_again;
530 		}
531 		dbgp_printk("No device found in debug port\n");
532 		return -EIO;
533 	}
534 	dbgp_ehci_status("wait for port done");
535 
536 	/* Enable the debug port */
537 	ctrl = readl(&ehci_debug->control);
538 	ctrl |= DBGP_CLAIM;
539 	writel(ctrl, &ehci_debug->control);
540 	ctrl = readl(&ehci_debug->control);
541 	if ((ctrl & DBGP_CLAIM) != DBGP_CLAIM) {
542 		dbgp_printk("No device in debug port\n");
543 		writel(ctrl & ~DBGP_CLAIM, &ehci_debug->control);
544 		return -ENODEV;
545 	}
546 	dbgp_ehci_status("debug ported enabled");
547 
548 	/* Completely transfer the debug device to the debug controller */
549 	portsc = readl(&ehci_regs->port_status[dbg_port - 1]);
550 	portsc &= ~PORT_PE;
551 	writel(portsc, &ehci_regs->port_status[dbg_port - 1]);
552 
553 	dbgp_mdelay(100);
554 
555 try_again:
556 	/* Find the debug device and make it device number 127 */
557 	for (devnum = 0; devnum <= 127; devnum++) {
558 		ret = dbgp_control_msg(devnum,
559 			USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
560 			USB_REQ_GET_DESCRIPTOR, (USB_DT_DEBUG << 8), 0,
561 			&dbgp_desc, sizeof(dbgp_desc));
562 		if (ret > 0)
563 			break;
564 	}
565 	if (devnum > 127) {
566 		dbgp_printk("Could not find attached debug device\n");
567 		goto err;
568 	}
569 	if (ret < 0) {
570 		dbgp_printk("Attached device is not a debug device\n");
571 		goto err;
572 	}
573 	dbgp_endpoint_out = dbgp_desc.bDebugOutEndpoint;
574 
575 	/* Move the device to 127 if it isn't already there */
576 	if (devnum != USB_DEBUG_DEVNUM) {
577 		ret = dbgp_control_msg(devnum,
578 			USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
579 			USB_REQ_SET_ADDRESS, USB_DEBUG_DEVNUM, 0, NULL, 0);
580 		if (ret < 0) {
581 			dbgp_printk("Could not move attached device to %d\n",
582 				USB_DEBUG_DEVNUM);
583 			goto err;
584 		}
585 		devnum = USB_DEBUG_DEVNUM;
586 		dbgp_printk("debug device renamed to 127\n");
587 	}
588 
589 	/* Enable the debug interface */
590 	ret = dbgp_control_msg(USB_DEBUG_DEVNUM,
591 		USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
592 		USB_REQ_SET_FEATURE, USB_DEVICE_DEBUG_MODE, 0, NULL, 0);
593 	if (ret < 0) {
594 		dbgp_printk(" Could not enable the debug device\n");
595 		goto err;
596 	}
597 	dbgp_printk("debug interface enabled\n");
598 	/* Perform a small write to get the even/odd data state in sync
599 	 */
600 	ret = dbgp_bulk_write(USB_DEBUG_DEVNUM, dbgp_endpoint_out, " ", 1);
601 	if (ret < 0) {
602 		dbgp_printk("dbgp_bulk_write failed: %d\n", ret);
603 		goto err;
604 	}
605 	dbgp_printk("small write doned\n");
606 	dbgp_not_safe = 0;
607 
608 	return 0;
609 err:
610 	if (tries--)
611 		goto try_again;
612 	return -ENODEV;
613 }
614 EXPORT_SYMBOL_GPL(dbgp_external_startup);
615 
616 static int ehci_reset_port(int port)
617 {
618 	u32 portsc;
619 	u32 delay_time, delay;
620 	int loop;
621 
622 	dbgp_ehci_status("reset port");
623 	/* Reset the usb debug port */
624 	portsc = readl(&ehci_regs->port_status[port - 1]);
625 	portsc &= ~PORT_PE;
626 	portsc |= PORT_RESET;
627 	writel(portsc, &ehci_regs->port_status[port - 1]);
628 
629 	delay = HUB_ROOT_RESET_TIME;
630 	for (delay_time = 0; delay_time < HUB_RESET_TIMEOUT;
631 	     delay_time += delay) {
632 		dbgp_mdelay(delay);
633 		portsc = readl(&ehci_regs->port_status[port - 1]);
634 		if (!(portsc & PORT_RESET))
635 			break;
636 	}
637 		if (portsc & PORT_RESET) {
638 			/* force reset to complete */
639 			loop = 100 * 1000;
640 			writel(portsc & ~(PORT_RWC_BITS | PORT_RESET),
641 				&ehci_regs->port_status[port - 1]);
642 			do {
643 				udelay(1);
644 				portsc = readl(&ehci_regs->port_status[port-1]);
645 			} while ((portsc & PORT_RESET) && (--loop > 0));
646 		}
647 
648 		/* Device went away? */
649 		if (!(portsc & PORT_CONNECT))
650 			return -ENOTCONN;
651 
652 		/* bomb out completely if something weird happend */
653 		if ((portsc & PORT_CSC))
654 			return -EINVAL;
655 
656 		/* If we've finished resetting, then break out of the loop */
657 		if (!(portsc & PORT_RESET) && (portsc & PORT_PE))
658 			return 0;
659 	return -EBUSY;
660 }
661 
662 static int ehci_wait_for_port(int port)
663 {
664 	u32 status;
665 	int ret, reps;
666 
667 	for (reps = 0; reps < 300; reps++) {
668 		status = readl(&ehci_regs->status);
669 		if (status & STS_PCD)
670 			break;
671 		dbgp_mdelay(1);
672 	}
673 	ret = ehci_reset_port(port);
674 	if (ret == 0)
675 		return 0;
676 	return -ENOTCONN;
677 }
678 
679 typedef void (*set_debug_port_t)(int port);
680 
681 static void __init default_set_debug_port(int port)
682 {
683 }
684 
685 static set_debug_port_t __initdata set_debug_port = default_set_debug_port;
686 
687 static void __init nvidia_set_debug_port(int port)
688 {
689 	u32 dword;
690 	dword = read_pci_config(ehci_dev.bus, ehci_dev.slot, ehci_dev.func,
691 				 0x74);
692 	dword &= ~(0x0f<<12);
693 	dword |= ((port & 0x0f)<<12);
694 	write_pci_config(ehci_dev.bus, ehci_dev.slot, ehci_dev.func, 0x74,
695 				 dword);
696 	dbgp_printk("set debug port to %d\n", port);
697 }
698 
699 static void __init detect_set_debug_port(void)
700 {
701 	u32 vendorid;
702 
703 	vendorid = read_pci_config(ehci_dev.bus, ehci_dev.slot, ehci_dev.func,
704 		 0x00);
705 
706 	if ((vendorid & 0xffff) == 0x10de) {
707 		dbgp_printk("using nvidia set_debug_port\n");
708 		set_debug_port = nvidia_set_debug_port;
709 	}
710 }
711 
712 /* The code in early_ehci_bios_handoff() is derived from the usb pci
713  * quirk initialization, but altered so as to use the early PCI
714  * routines. */
715 #define EHCI_USBLEGSUP_BIOS	(1 << 16)	/* BIOS semaphore */
716 #define EHCI_USBLEGCTLSTS	4		/* legacy control/status */
717 static void __init early_ehci_bios_handoff(void)
718 {
719 	u32 hcc_params = readl(&ehci_caps->hcc_params);
720 	int offset = (hcc_params >> 8) & 0xff;
721 	u32 cap;
722 	int msec;
723 
724 	if (!offset)
725 		return;
726 
727 	cap = read_pci_config(ehci_dev.bus, ehci_dev.slot,
728 			      ehci_dev.func, offset);
729 	dbgp_printk("dbgp: ehci BIOS state %08x\n", cap);
730 
731 	if ((cap & 0xff) == 1 && (cap & EHCI_USBLEGSUP_BIOS)) {
732 		dbgp_printk("dbgp: BIOS handoff\n");
733 		write_pci_config_byte(ehci_dev.bus, ehci_dev.slot,
734 				      ehci_dev.func, offset + 3, 1);
735 	}
736 
737 	/* if boot firmware now owns EHCI, spin till it hands it over. */
738 	msec = 1000;
739 	while ((cap & EHCI_USBLEGSUP_BIOS) && (msec > 0)) {
740 		mdelay(10);
741 		msec -= 10;
742 		cap = read_pci_config(ehci_dev.bus, ehci_dev.slot,
743 				      ehci_dev.func, offset);
744 	}
745 
746 	if (cap & EHCI_USBLEGSUP_BIOS) {
747 		/* well, possibly buggy BIOS... try to shut it down,
748 		 * and hope nothing goes too wrong */
749 		dbgp_printk("dbgp: BIOS handoff failed: %08x\n", cap);
750 		write_pci_config_byte(ehci_dev.bus, ehci_dev.slot,
751 				      ehci_dev.func, offset + 2, 0);
752 	}
753 
754 	/* just in case, always disable EHCI SMIs */
755 	write_pci_config_byte(ehci_dev.bus, ehci_dev.slot, ehci_dev.func,
756 			      offset + EHCI_USBLEGCTLSTS, 0);
757 }
758 
759 static int __init ehci_setup(void)
760 {
761 	u32 ctrl, portsc, hcs_params;
762 	u32 debug_port, new_debug_port = 0, n_ports;
763 	int ret, i;
764 	int port_map_tried;
765 	int playtimes = 3;
766 
767 	early_ehci_bios_handoff();
768 
769 try_next_time:
770 	port_map_tried = 0;
771 
772 try_next_port:
773 
774 	hcs_params = readl(&ehci_caps->hcs_params);
775 	debug_port = HCS_DEBUG_PORT(hcs_params);
776 	dbgp_phys_port = debug_port;
777 	n_ports    = HCS_N_PORTS(hcs_params);
778 
779 	dbgp_printk("debug_port: %d\n", debug_port);
780 	dbgp_printk("n_ports:    %d\n", n_ports);
781 	dbgp_ehci_status("");
782 
783 	for (i = 1; i <= n_ports; i++) {
784 		portsc = readl(&ehci_regs->port_status[i-1]);
785 		dbgp_printk("portstatus%d: %08x\n", i, portsc);
786 	}
787 
788 	if (port_map_tried && (new_debug_port != debug_port)) {
789 		if (--playtimes) {
790 			set_debug_port(new_debug_port);
791 			goto try_next_time;
792 		}
793 		return -1;
794 	}
795 
796 	/* Only reset the controller if it is not already in the
797 	 * configured state */
798 	if (!(readl(&ehci_regs->configured_flag) & FLAG_CF)) {
799 		if (dbgp_ehci_controller_reset() != 0)
800 			return -1;
801 	} else {
802 		dbgp_ehci_status("ehci skip - already configured");
803 	}
804 
805 	ret = dbgp_external_startup();
806 	if (ret == -EIO)
807 		goto next_debug_port;
808 
809 	if (ret < 0) {
810 		/* Things didn't work so remove my claim */
811 		ctrl = readl(&ehci_debug->control);
812 		ctrl &= ~(DBGP_CLAIM | DBGP_OUT);
813 		writel(ctrl, &ehci_debug->control);
814 		return -1;
815 	}
816 	return 0;
817 
818 next_debug_port:
819 	port_map_tried |= (1<<(debug_port - 1));
820 	new_debug_port = ((debug_port-1+1)%n_ports) + 1;
821 	if (port_map_tried != ((1<<n_ports) - 1)) {
822 		set_debug_port(new_debug_port);
823 		goto try_next_port;
824 	}
825 	if (--playtimes) {
826 		set_debug_port(new_debug_port);
827 		goto try_next_time;
828 	}
829 
830 	return -1;
831 }
832 
833 int __init early_dbgp_init(char *s)
834 {
835 	u32 debug_port, bar, offset;
836 	u32 bus, slot, func, cap;
837 	void __iomem *ehci_bar;
838 	u32 dbgp_num;
839 	u32 bar_val;
840 	char *e;
841 	int ret;
842 	u8 byte;
843 
844 	if (!early_pci_allowed())
845 		return -1;
846 
847 	dbgp_num = 0;
848 	if (*s)
849 		dbgp_num = simple_strtoul(s, &e, 10);
850 	dbgp_printk("dbgp_num: %d\n", dbgp_num);
851 
852 	cap = find_dbgp(dbgp_num, &bus, &slot, &func);
853 	if (!cap)
854 		return -1;
855 
856 	dbgp_printk("Found EHCI debug port on %02x:%02x.%1x\n", bus, slot,
857 			 func);
858 
859 	debug_port = read_pci_config(bus, slot, func, cap);
860 	bar = (debug_port >> 29) & 0x7;
861 	bar = (bar * 4) + 0xc;
862 	offset = (debug_port >> 16) & 0xfff;
863 	dbgp_printk("bar: %02x offset: %03x\n", bar, offset);
864 	if (bar != PCI_BASE_ADDRESS_0) {
865 		dbgp_printk("only debug ports on bar 1 handled.\n");
866 
867 		return -1;
868 	}
869 
870 	bar_val = read_pci_config(bus, slot, func, PCI_BASE_ADDRESS_0);
871 	dbgp_printk("bar_val: %02x offset: %03x\n", bar_val, offset);
872 	if (bar_val & ~PCI_BASE_ADDRESS_MEM_MASK) {
873 		dbgp_printk("only simple 32bit mmio bars supported\n");
874 
875 		return -1;
876 	}
877 
878 	/* double check if the mem space is enabled */
879 	byte = read_pci_config_byte(bus, slot, func, 0x04);
880 	if (!(byte & 0x2)) {
881 		byte  |= 0x02;
882 		write_pci_config_byte(bus, slot, func, 0x04, byte);
883 		dbgp_printk("mmio for ehci enabled\n");
884 	}
885 
886 	/*
887 	 * FIXME I don't have the bar size so just guess PAGE_SIZE is more
888 	 * than enough.  1K is the biggest I have seen.
889 	 */
890 	set_fixmap_nocache(FIX_DBGP_BASE, bar_val & PAGE_MASK);
891 	ehci_bar = (void __iomem *)__fix_to_virt(FIX_DBGP_BASE);
892 	ehci_bar += bar_val & ~PAGE_MASK;
893 	dbgp_printk("ehci_bar: %p\n", ehci_bar);
894 
895 	ehci_caps  = ehci_bar;
896 	ehci_regs  = ehci_bar + HC_LENGTH(readl(&ehci_caps->hc_capbase));
897 	ehci_debug = ehci_bar + offset;
898 	ehci_dev.bus = bus;
899 	ehci_dev.slot = slot;
900 	ehci_dev.func = func;
901 
902 	detect_set_debug_port();
903 
904 	ret = ehci_setup();
905 	if (ret < 0) {
906 		dbgp_printk("ehci_setup failed\n");
907 		ehci_debug = NULL;
908 
909 		return -1;
910 	}
911 	dbgp_ehci_status("early_init_complete");
912 
913 	return 0;
914 }
915 
916 static void early_dbgp_write(struct console *con, const char *str, u32 n)
917 {
918 	int chunk, ret;
919 	char buf[DBGP_MAX_PACKET];
920 	int use_cr = 0;
921 	u32 cmd, ctrl;
922 	int reset_run = 0;
923 
924 	if (!ehci_debug || dbgp_not_safe)
925 		return;
926 
927 	cmd = readl(&ehci_regs->command);
928 	if (unlikely(!(cmd & CMD_RUN))) {
929 		/* If the ehci controller is not in the run state do extended
930 		 * checks to see if the acpi or some other initialization also
931 		 * reset the ehci debug port */
932 		ctrl = readl(&ehci_debug->control);
933 		if (!(ctrl & DBGP_ENABLED)) {
934 			dbgp_not_safe = 1;
935 			dbgp_external_startup();
936 		} else {
937 			cmd |= CMD_RUN;
938 			writel(cmd, &ehci_regs->command);
939 			reset_run = 1;
940 		}
941 	}
942 	while (n > 0) {
943 		for (chunk = 0; chunk < DBGP_MAX_PACKET && n > 0;
944 		     str++, chunk++, n--) {
945 			if (!use_cr && *str == '\n') {
946 				use_cr = 1;
947 				buf[chunk] = '\r';
948 				str--;
949 				n++;
950 				continue;
951 			}
952 			if (use_cr)
953 				use_cr = 0;
954 			buf[chunk] = *str;
955 		}
956 		if (chunk > 0) {
957 			ret = dbgp_bulk_write(USB_DEBUG_DEVNUM,
958 				      dbgp_endpoint_out, buf, chunk);
959 		}
960 	}
961 	if (unlikely(reset_run)) {
962 		cmd = readl(&ehci_regs->command);
963 		cmd &= ~CMD_RUN;
964 		writel(cmd, &ehci_regs->command);
965 	}
966 }
967 
968 struct console early_dbgp_console = {
969 	.name =		"earlydbg",
970 	.write =	early_dbgp_write,
971 	.flags =	CON_PRINTBUFFER,
972 	.index =	-1,
973 };
974 
975 int dbgp_reset_prep(void)
976 {
977 	u32 ctrl;
978 
979 	dbgp_not_safe = 1;
980 	if (!ehci_debug)
981 		return 0;
982 
983 	if (early_dbgp_console.index != -1 &&
984 		!(early_dbgp_console.flags & CON_BOOT))
985 		return 1;
986 	/* This means the console is not initialized, or should get
987 	 * shutdown so as to allow for reuse of the usb device, which
988 	 * means it is time to shutdown the usb debug port. */
989 	ctrl = readl(&ehci_debug->control);
990 	if (ctrl & DBGP_ENABLED) {
991 		ctrl &= ~(DBGP_CLAIM);
992 		writel(ctrl, &ehci_debug->control);
993 	}
994 	return 0;
995 }
996 EXPORT_SYMBOL_GPL(dbgp_reset_prep);
997