summaryrefslogtreecommitdiff
path: root/src/devices/hypertransport.c
blob: 6d4836b87a0c204aa45cd1a15292916f2668da91 (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
/*
 * This file is part of the LinuxBIOS project.
 *
 * Copyright (C) 2003-2004 Linux Networx
 * (Written by Eric Biederman <ebiederman@lnxi.com> for Linux Networx)
 * Copyright (C) 2004 David Hendricks <sc@flagen.com>
 * Copyright (C) 2004 Li-Ta Lo <ollie@lanl.gov>
 * Copyright (C) 2005-2006 Tyan
 * (Written by Yinghai Lu <yhlu@tyan.com> for Tyan)
 * Copyright (C) 2005-2006 Stefan Reinauer <stepan@openbios.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

/*
	2005.11 yhlu add let the real sb to use small uintid
*/

#include <bitops.h>
#include <console/console.h>
#include <device/device.h>
#include <device/path.h>
#include <device/pci.h>
#include <device/pci_ids.h>
#include <device/hypertransport.h>
#include <part/hard_reset.h>
#include <part/fallback_boot.h>

#define OPT_HT_LINK 0
        
#if OPT_HT_LINK == 1
#include <cpu/amd/model_fxx_rev.h>
#endif

static device_t ht_scan_get_devs(device_t *old_devices)
{
	device_t first, last;
	first = *old_devices;
	last = first;
	/* Extract the chain of devices to (first through last)
	 * for the next hypertransport device.
	 */
	while(last && last->sibling && 
		(last->sibling->path.type == DEVICE_PATH_PCI) &&
		(last->sibling->path.u.pci.devfn > last->path.u.pci.devfn)) 
	{
		last = last->sibling;
	}
	if (first) {
		device_t child;
		/* Unlink the chain from the list of old devices */
		*old_devices = last->sibling;
		last->sibling = 0;

		/* Now add the device to the list of devices on the bus.
		 */
		/* Find the last child of our parent */
		for(child = first->bus->children; child && child->sibling; ) {
			child = child->sibling;
		}
		/* Place the chain on the list of children of their parent. */
		if (child) {
			child->sibling = first;
		} else {
			first->bus->children = first;
		}
	}
	return first;
}

#if OPT_HT_LINK == 1
static unsigned ht_read_freq_cap(device_t dev, unsigned pos)
{
	/* Handle bugs in valid hypertransport frequency reporting */
	unsigned freq_cap;

	freq_cap = pci_read_config16(dev, pos);
	freq_cap &= ~(1 << HT_FREQ_VENDOR); /* Ignore Vendor HT frequencies */

	/* AMD 8131 Errata 48 */
	if ((dev->vendor == PCI_VENDOR_ID_AMD) &&
		(dev->device == PCI_DEVICE_ID_AMD_8131_PCIX)) {
		freq_cap &= ~(1 << HT_FREQ_800Mhz);
	}
	/* AMD 8151 Errata 23 */
	if ((dev->vendor == PCI_VENDOR_ID_AMD) &&
		(dev->device == PCI_DEVICE_ID_AMD_8151_SYSCTRL)) {
		freq_cap &= ~(1 << HT_FREQ_800Mhz);
	}
	/* AMD K8 Unsupported 1Ghz? */
	if ((dev->vendor == PCI_VENDOR_ID_AMD) && (dev->device == 0x1100)) {
#if K8_HT_FREQ_1G_SUPPORT == 1 
	#if K8_REV_F_SUPPORT == 0 
		if (is_cpu_pre_e0()) { // only e0 later suupport 1GHz HT
			freq_cap &= ~(1 << HT_FREQ_1000Mhz);
		} 
	#endif
#else
		freq_cap &= ~(1 << HT_FREQ_1000Mhz);
#endif

	}
	return freq_cap;
}
#endif

struct ht_link {
	struct device *dev;
	unsigned pos;
	unsigned char ctrl_off, config_off, freq_off, freq_cap_off;
};

static int ht_setup_link(struct ht_link *prev, device_t dev, unsigned pos)
{
	static const uint8_t link_width_to_pow2[]= { 3, 4, 0, 5, 1, 2, 0, 0 };
	static const uint8_t pow2_to_link_width[] = { 0x7, 4, 5, 0, 1, 3 };
	struct ht_link cur[1];
	unsigned present_width_cap,    upstream_width_cap;
	unsigned present_freq_cap,     upstream_freq_cap;
	unsigned ln_present_width_in,  ln_upstream_width_in; 
	unsigned ln_present_width_out, ln_upstream_width_out;
	unsigned freq, old_freq;
	unsigned present_width, upstream_width, old_width;
	int reset_needed;
	int linkb_to_host;

	/* Set the hypertransport link width and frequency */
	reset_needed = 0;
	/* See which side of the device our previous write to 
	 * set the unitid came from.
	 */
	cur->dev = dev;
	cur->pos = pos;
	linkb_to_host = (pci_read_config16(cur->dev, cur->pos + PCI_CAP_FLAGS) >> 10) & 1;
	if (!linkb_to_host) {
		cur->ctrl_off     = PCI_HT_CAP_SLAVE_CTRL0;
		cur->config_off   = PCI_HT_CAP_SLAVE_WIDTH0;
		cur->freq_off     = PCI_HT_CAP_SLAVE_FREQ0;
		cur->freq_cap_off = PCI_HT_CAP_SLAVE_FREQ_CAP0;
	}
	else {
		cur->ctrl_off     = PCI_HT_CAP_SLAVE_CTRL1;
		cur->config_off   = PCI_HT_CAP_SLAVE_WIDTH1;
		cur->freq_off     = PCI_HT_CAP_SLAVE_FREQ1;
		cur->freq_cap_off = PCI_HT_CAP_SLAVE_FREQ_CAP1;
	}
#if OPT_HT_LINK == 1
	/* Read the capabilities */
	present_freq_cap   = ht_read_freq_cap(cur->dev, cur->pos + cur->freq_cap_off);
	upstream_freq_cap  = ht_read_freq_cap(prev->dev, prev->pos + prev->freq_cap_off);
	present_width_cap  = pci_read_config8(cur->dev, cur->pos + cur->config_off);
	upstream_width_cap = pci_read_config8(prev->dev, prev->pos + prev->config_off);
	
	/* Calculate the highest useable frequency */
	freq = log2(present_freq_cap & upstream_freq_cap);

	/* Calculate the highest width */
	ln_upstream_width_in = link_width_to_pow2[upstream_width_cap & 7];
	ln_present_width_out = link_width_to_pow2[(present_width_cap >> 4) & 7];
	if (ln_upstream_width_in > ln_present_width_out) {
		ln_upstream_width_in = ln_present_width_out;
	}
	upstream_width = pow2_to_link_width[ln_upstream_width_in];
	present_width  = pow2_to_link_width[ln_upstream_width_in] << 4;

	ln_upstream_width_out = link_width_to_pow2[(upstream_width_cap >> 4) & 7];
	ln_present_width_in   = link_width_to_pow2[present_width_cap & 7];
	if (ln_upstream_width_out > ln_present_width_in) {
		ln_upstream_width_out = ln_present_width_in;
	}
	upstream_width |= pow2_to_link_width[ln_upstream_width_out] << 4;
	present_width  |= pow2_to_link_width[ln_upstream_width_out];

	/* Set the current device */
	old_freq = pci_read_config8(cur->dev, cur->pos + cur->freq_off);
	old_freq &= 0x0f;
	if (freq != old_freq) {
		unsigned new_freq;
		pci_write_config8(cur->dev, cur->pos + cur->freq_off, freq);
		reset_needed = 1;
		printk_spew("HyperT FreqP old %x new %x\n",old_freq,freq);
		new_freq = pci_read_config8(cur->dev, cur->pos + cur->freq_off);
		new_freq &= 0x0f;
		if (new_freq != freq) {
			printk_err("%s Hypertransport frequency would not set wanted: %x got: %x\n",
				dev_path(dev), freq, new_freq);
		}
	}
	old_width = pci_read_config8(cur->dev, cur->pos + cur->config_off + 1);
	if (present_width != old_width) {
		unsigned new_width;
		pci_write_config8(cur->dev, cur->pos + cur->config_off + 1,
			present_width);
		reset_needed = 1;
		printk_spew("HyperT widthP old %x new %x\n",old_width, present_width);
		new_width = pci_read_config8(cur->dev, cur->pos + cur->config_off + 1);
		if (new_width != present_width) {
			printk_err("%s Hypertransport width would not set wanted: %x got: %x\n",
				dev_path(dev), present_width, new_width);
		}
	}

	/* Set the upstream device */
	old_freq = pci_read_config8(prev->dev, prev->pos + prev->freq_off);
	old_freq &= 0x0f;
	if (freq != old_freq) {
		unsigned new_freq;
		pci_write_config8(prev->dev, prev->pos + prev->freq_off, freq);
		reset_needed = 1;
		printk_spew("HyperT freqU old %x new %x\n", old_freq, freq);
		new_freq = pci_read_config8(prev->dev, prev->pos + prev->freq_off);
		new_freq &= 0x0f;
		if (new_freq != freq) {
			printk_err("%s Hypertransport frequency would not set wanted: %x got: %x\n",
				dev_path(prev->dev), freq, new_freq);
		}
	}
	old_width = pci_read_config8(prev->dev, prev->pos + prev->config_off + 1);
	if (upstream_width != old_width) {
		unsigned new_width;
		pci_write_config8(prev->dev, prev->pos + prev->config_off + 1, upstream_width);
		reset_needed = 1;
		printk_spew("HyperT widthU old %x new %x\n", old_width, upstream_width);
		new_width = pci_read_config8(prev->dev, prev->pos + prev->config_off + 1);
		if (new_width != upstream_width) {
			printk_err("%s Hypertransport width would not set wanted: %x got: %x\n",
				dev_path(prev->dev), upstream_width, new_width);
		}
	}
#endif
	
	/* Remember the current link as the previous link,
	 * But look at the other offsets.
	 */
	prev->dev = cur->dev;
	prev->pos = cur->pos;
	if (cur->ctrl_off == PCI_HT_CAP_SLAVE_CTRL0) {
		prev->ctrl_off     = PCI_HT_CAP_SLAVE_CTRL1;
		prev->config_off   = PCI_HT_CAP_SLAVE_WIDTH1;
		prev->freq_off     = PCI_HT_CAP_SLAVE_FREQ1;
		prev->freq_cap_off = PCI_HT_CAP_SLAVE_FREQ_CAP1;
	} else {
		prev->ctrl_off     = PCI_HT_CAP_SLAVE_CTRL0;
		prev->config_off   = PCI_HT_CAP_SLAVE_WIDTH0;
		prev->freq_off     = PCI_HT_CAP_SLAVE_FREQ0;
		prev->freq_cap_off = PCI_HT_CAP_SLAVE_FREQ_CAP0;
	}

	return reset_needed;
		
}

static unsigned ht_lookup_slave_capability(struct device *dev)
{
	unsigned pos;
	pos = 0;
	do {
		pos = pci_find_next_capability(dev, PCI_CAP_ID_HT, pos);
		if (pos) {
			unsigned flags;
			flags = pci_read_config16(dev, pos + PCI_CAP_FLAGS);
			printk_spew("flags: 0x%04x\n", flags);
			if ((flags >> 13) == 0) {
				/* Entry is a Slave secondary, success... */
				break;
			}
		}
	} while(pos);
	return pos;
}

static void ht_collapse_early_enumeration(struct bus *bus, unsigned offset_unitid)
{
	unsigned int devfn;
	struct ht_link prev;
	unsigned ctrl;

	/* Initialize the hypertransport enumeration state */
	prev.dev = bus->dev;
	prev.pos = bus->cap;
	prev.ctrl_off     = PCI_HT_CAP_HOST_CTRL;
	prev.config_off   = PCI_HT_CAP_HOST_WIDTH;
	prev.freq_off     = PCI_HT_CAP_HOST_FREQ;
	prev.freq_cap_off = PCI_HT_CAP_HOST_FREQ_CAP;

	/* Wait until the link initialization is complete */
	do {
		ctrl = pci_read_config16(prev.dev, prev.pos + prev.ctrl_off);
		/* Is this the end of the hypertransport chain */
		if (ctrl & (1 << 6)) {
			return;
		}
		/* Has the link failed? */
		if (ctrl & (1 << 4)) {
			/*
			 * Either the link has failed, or we have
			 * a CRC error.
			 * Sometimes this can happen due to link
			 * retrain, so lets knock it down and see
			 * if its transient
			 */
			ctrl |= ((1 << 4) | (1 <<8)); // Link fail + Crc
			pci_write_config16(prev.dev, prev.pos + prev.ctrl_off, ctrl);
			ctrl = pci_read_config16(prev.dev, prev.pos + prev.ctrl_off);
			if (ctrl & ((1 << 4) | (1 << 8))) {
				printk_alert("Detected error on Hypertransport Link\n");
				return;
			}
		}
	} while((ctrl & (1 << 5)) == 0);

	        //actually, only for one HT device HT chain, and unitid is 0
#if HT_CHAIN_UNITID_BASE == 0
        if(offset_unitid) {
                return;
        }
#endif

        /* Check if is already collapsed */
        if((!offset_unitid)|| (offset_unitid && (!((HT_CHAIN_END_UNITID_BASE == 0) && (HT_CHAIN_END_UNITID_BASE <HT_CHAIN_UNITID_BASE))))) {
                struct device dummy;
                uint32_t id;
                dummy.bus              = bus;
                dummy.path.type        = DEVICE_PATH_PCI;
                dummy.path.u.pci.devfn = PCI_DEVFN(0, 0);
                id = pci_read_config32(&dummy, PCI_VENDOR_ID);
                if ( ! ( (id == 0xffffffff) || (id == 0x00000000) ||
                    (id == 0x0000ffff) || (id == 0xffff0000) ) ) {
                             return;
                }
        }

	/* Spin through the devices and collapse any early
	 * hypertransport enumeration.
	 */
	for(devfn = PCI_DEVFN(1, 0); devfn <= 0xff; devfn += 8) {
		struct device dummy;
		uint32_t id;
		unsigned pos, flags;
		dummy.bus              = bus;
		dummy.path.type        = DEVICE_PATH_PCI;
		dummy.path.u.pci.devfn = devfn;
		id = pci_read_config32(&dummy, PCI_VENDOR_ID);
		if (	(id == 0xffffffff) || (id == 0x00000000) || 
			(id == 0x0000ffff) || (id == 0xffff0000)) {
			continue;
		}
		dummy.vendor = id & 0xffff;
		dummy.device = (id >> 16) & 0xffff;
		dummy.hdr_type = pci_read_config8(&dummy, PCI_HEADER_TYPE);
		pos = ht_lookup_slave_capability(&dummy);
		if (!pos){
			continue;
		}

		/* Clear the unitid */
		flags = pci_read_config16(&dummy, pos + PCI_CAP_FLAGS);
		flags &= ~0x1f;
		pci_write_config16(&dummy, pos + PCI_CAP_FLAGS, flags);
		printk_spew("Collapsing %s [%04x/%04x]\n", 
			dev_path(&dummy), dummy.vendor, dummy.device);
	}
}

unsigned int hypertransport_scan_chain(struct bus *bus, 
	unsigned min_devfn, unsigned max_devfn, unsigned int max, unsigned *ht_unitid_base, unsigned offset_unitid)
{
	//even HT_CHAIN_UNITID_BASE == 0, we still can go through this function, because of end_of_chain check, also We need it to optimize link
	unsigned next_unitid, last_unitid;
	device_t old_devices, dev, func;
	unsigned min_unitid = (offset_unitid) ? HT_CHAIN_UNITID_BASE:1;
	struct ht_link prev;
	device_t last_func = 0;
	int ht_dev_num = 0;

#if HT_CHAIN_END_UNITID_BASE < HT_CHAIN_UNITID_BASE
        //let't record the device of last ht device, So we can set the Unitid to HT_CHAIN_END_UNITID_BASE
        unsigned real_last_unitid; 
        uint8_t real_last_pos;
	device_t real_last_dev;
#endif

	/* Restore the hypertransport chain to it's unitialized state */
	ht_collapse_early_enumeration(bus, offset_unitid);

	/* See which static device nodes I have */
	old_devices = bus->children;
	bus->children = 0;

	/* Initialize the hypertransport enumeration state */
	prev.dev = bus->dev;
	prev.pos = bus->cap;
	prev.ctrl_off     = PCI_HT_CAP_HOST_CTRL;
	prev.config_off   = PCI_HT_CAP_HOST_WIDTH;
	prev.freq_off     = PCI_HT_CAP_HOST_FREQ;
	prev.freq_cap_off = PCI_HT_CAP_HOST_FREQ_CAP;
	
	/* If present assign unitid to a hypertransport chain */
	last_unitid = min_unitid -1;
	next_unitid = min_unitid;
	do {
		uint8_t pos;
		uint16_t flags;
		unsigned count, static_count;
		unsigned ctrl;

		last_unitid = next_unitid;

		/* Wait until the link initialization is complete */
		do {
			ctrl = pci_read_config16(prev.dev, prev.pos + prev.ctrl_off);

			if (ctrl & (1 << 6))
				goto end_of_chain;	// End of chain

			if (ctrl & ((1 << 4) | (1 << 8))) {
				/*
				 * Either the link has failed, or we have
				 * a CRC error.
				 * Sometimes this can happen due to link
				 * retrain, so lets knock it down and see
				 * if its transient
				 */
				ctrl |= ((1 << 4) | (1 <<8)); // Link fail + Crc
				pci_write_config16(prev.dev, prev.pos + prev.ctrl_off, ctrl);
				ctrl = pci_read_config16(prev.dev, prev.pos + prev.ctrl_off);
				if (ctrl & ((1 << 4) | (1 << 8))) {
					printk_alert("Detected error on Hypertransport Link\n");
					goto end_of_chain;
				}
			}
		} while((ctrl & (1 << 5)) == 0);
		

		/* Get and setup the device_structure */
		dev = ht_scan_get_devs(&old_devices);

		/* See if a device is present and setup the
		 * device structure.
		 */
		dev = pci_probe_dev(dev, bus, 0);
		if (!dev || !dev->enabled) {
			break;
		}

		/* Find the hypertransport link capability */
		pos = ht_lookup_slave_capability(dev);
		if (pos == 0) {
			printk_err("%s Hypertransport link capability not found", 
				dev_path(dev));
			break;
		}
		
		/* Update the Unitid of the current device */
		flags = pci_read_config16(dev, pos + PCI_CAP_FLAGS);
        
		/* If the devices has a unitid set and is at devfn 0 we are done. 
		 * This can happen with shadow hypertransport devices,
		 * or if we have reached the bottom of a
		 * hypertransport device chain.
		 */
		if (flags & 0x1f) {
			break;
		}

		flags &= ~0x1f; /* mask out base Unit ID */
                flags |= next_unitid & 0x1f;
                pci_write_config16(dev, pos + PCI_CAP_FLAGS, flags);

		/* Update the Unitd id in the device structure */
		static_count = 1;
		for(func = dev; func; func = func->sibling) {
			func->path.u.pci.devfn += (next_unitid << 3);
			static_count = (func->path.u.pci.devfn >> 3) 
				- (dev->path.u.pci.devfn >> 3) + 1;
			last_func = func;
		}

		/* Compute the number of unitids consumed */
		count = (flags >> 5) & 0x1f; /* get unit count */
		printk_spew("%s count: %04x static_count: %04x\n", 
			dev_path(dev), count, static_count);
		if (count < static_count) {
			count = static_count;
		}

		/* Update the Unitid of the next device */
		ht_unitid_base[ht_dev_num] = next_unitid;
		ht_dev_num++;
#if HT_CHAIN_END_UNITID_BASE < HT_CHAIN_UNITID_BASE
		if(offset_unitid) {
	                real_last_unitid = next_unitid;
        	        real_last_pos = pos;
			real_last_dev = dev;
		}
#endif
		next_unitid += count;

		/* Setup the hypetransport link */
		bus->reset_needed |= ht_setup_link(&prev, dev, pos);

		printk_debug("%s [%04x/%04x] %s next_unitid: %04x\n",
			dev_path(dev),
			dev->vendor, dev->device, 
			(dev->enabled? "enabled": "disabled"), next_unitid);

	} while((last_unitid != next_unitid) && (next_unitid <= (max_devfn >> 3)));
 end_of_chain:
#if OPT_HT_LINK == 1
	if(bus->reset_needed) {
		printk_info("HyperT reset needed\n");
	}
	else {
		printk_debug("HyperT reset not needed\n");
	}
#endif

#if HT_CHAIN_END_UNITID_BASE < HT_CHAIN_UNITID_BASE
        if(offset_unitid && (ht_dev_num>0)) {
                uint16_t flags;
                int i;
		device_t last_func = 0;
                flags = pci_read_config16(real_last_dev, real_last_pos + PCI_CAP_FLAGS);
                flags &= ~0x1f;
                flags |= HT_CHAIN_END_UNITID_BASE & 0x1f;
                pci_write_config16(real_last_dev, real_last_pos + PCI_CAP_FLAGS, flags);

                for(func = real_last_dev; func; func = func->sibling) {
                        func->path.u.pci.devfn -= ((real_last_unitid - HT_CHAIN_END_UNITID_BASE) << 3);
			last_func = func;
                }
		
		ht_unitid_base[ht_dev_num-1] = HT_CHAIN_END_UNITID_BASE; // update last one
		
                next_unitid = real_last_unitid;
        }
#endif

	if (next_unitid > 0x1f) {
		next_unitid = 0x1f;
	}

	/* Die if any leftover Static devices are are found.  
	 * There's probably a problem in the Config.lb.
	 */
	if(old_devices) {
		device_t left;
		for(left = old_devices; left; left = left->sibling) {
			printk_debug("%s\n", dev_path(left));
		}
		printk_err("HT: Left over static devices.  Check your Config.lb\n");
		if(last_func  && !last_func->sibling) // put back the left over static device, and let pci_scan_bus disable it
			last_func->sibling = old_devices; 
	}

	/* Now that nothing is overlapping it is safe to scan the
	 * children. 
	 */
	max = pci_scan_bus(bus, 0x00, (next_unitid << 3)|7, max); 
	return max; 
}

/**
 * @brief Scan a PCI bridge and the buses behind the bridge.
 *
 * Determine the existence of buses behind the bridge. Set up the bridge
 * according to the result of the scan.
 *
 * This function is the default scan_bus() method for PCI bridge devices.
 *
 * @param dev pointer to the bridge device
 * @param max the highest bus number assgined up to now
 *
 * @return The maximum bus number found, after scanning all subordinate busses
 */
unsigned int hypertransport_scan_chain_x(struct bus *bus,
        unsigned min_devfn, unsigned max_devfn, unsigned int max)
{
	unsigned ht_unitid_base[4];
	unsigned offset_unitid = 1;
	return hypertransport_scan_chain(bus, min_devfn, max_devfn, max, ht_unitid_base, offset_unitid);
}

unsigned int ht_scan_bridge(struct device *dev, unsigned int max)
{
	return do_pci_scan_bridge(dev, max, hypertransport_scan_chain_x);
}


/** Default device operations for hypertransport bridges */
static struct pci_operations ht_bus_ops_pci = {
	.set_subsystem = 0,
};

struct device_operations default_ht_ops_bus = {
	.read_resources   = pci_bus_read_resources,
	.set_resources    = pci_dev_set_resources,
	.enable_resources = pci_bus_enable_resources,
	.init		  = 0,
	.scan_bus	  = ht_scan_bridge,
	.enable           = 0,
	.reset_bus        = pci_bus_reset,
	.ops_pci          = &ht_bus_ops_pci,
};