src/devices/hypertransport.c

   1 /*
   2  * This file is part of the coreboot project.
   3  *
   4  * Copyright (C) 2003-2004 Linux Networx
   5  * (Written by Eric Biederman <ebiederman@lnxi.com> for Linux Networx)
   6  * Copyright (C) 2004 David Hendricks <sc@flagen.com>
   7  * Copyright (C) 2004 Li-Ta Lo <ollie@lanl.gov>
   8  * Copyright (C) 2005-2006 Tyan
   9  * (Written by Yinghai Lu <yhlu@tyan.com> for Tyan)
  10  * Copyright (C) 2005-2006 Stefan Reinauer <stepan@openbios.org>
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; version 2 of the License.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  24  */
  25
  26 #include <bitops.h>
  27 #include <console/console.h>
  28 #include <device/device.h>
  29 #include <device/path.h>
  30 #include <device/pci.h>
  31 #include <device/pci_ids.h>
  32 #include <device/hypertransport.h>
  33
  34 /*
  35  * The hypertransport link is already optimized in pre-RAM code so don't do
  36  * it again.
  37  */
  38 #define OPT_HT_LINK 0
  39
  40 #if OPT_HT_LINK == 1
  41 #include <cpu/amd/model_fxx_rev.h>
  42 #endif
  43
  44 static device_t ht_scan_get_devs(device_t *old_devices)
  45 {
  46         device_t first, last;
  47
  48         first = *old_devices;
  49         last = first;
  50
  51         /*
  52          * Extract the chain of devices to (first through last) for the next
  53          * hypertransport device.
  54          */
  55         while (last && last->sibling &&
  56                (last->sibling->path.type == DEVICE_PATH_PCI) &&
  57                (last->sibling->path.pci.devfn > last->path.pci.devfn))
  58         {
  59                 last = last->sibling;
  60         }
  61
  62         if (first) {
  63                 device_t child;
  64
  65                 /* Unlink the chain from the list of old devices. */
  66                 *old_devices = last->sibling;
  67                 last->sibling = 0;
  68
  69                 /* Now add the device to the list of devices on the bus. */
  70                 /* Find the last child of our parent. */
  71                 for (child = first->bus->children; child && child->sibling; )
  72                         child = child->sibling;
  73
  74                 /* Place the chain on the list of children of their parent. */
  75                 if (child)
  76                         child->sibling = first;
  77                 else
  78                         first->bus->children = first;
  79         }
  80         return first;
  81 }
  82
  83 #if OPT_HT_LINK == 1
  84 static unsigned ht_read_freq_cap(device_t dev, unsigned pos)
  85 {
  86         /* Handle bugs in valid hypertransport frequency reporting. */
  87         unsigned freq_cap;
  88
  89         freq_cap = pci_read_config16(dev, pos);
  90         freq_cap &= ~(1 << HT_FREQ_VENDOR); /* Ignore Vendor HT frequencies. */
  91
  92         /* AMD 8131 Errata 48. */
  93         if ((dev->vendor == PCI_VENDOR_ID_AMD) &&
  94             (dev->device == PCI_DEVICE_ID_AMD_8131_PCIX)) {
  95                 freq_cap &= ~(1 << HT_FREQ_800Mhz);
  96         }
  97
  98         /* AMD 8151 Errata 23. */
  99         if ((dev->vendor == PCI_VENDOR_ID_AMD) &&
 100             (dev->device == PCI_DEVICE_ID_AMD_8151_SYSCTRL)) {
 101                 freq_cap &= ~(1 << HT_FREQ_800Mhz);
 102         }
 103
 104         /* AMD K8 unsupported 1GHz? */
 105         if ((dev->vendor == PCI_VENDOR_ID_AMD) && (dev->device == 0x1100)) {
 106 #if CONFIG_K8_HT_FREQ_1G_SUPPORT == 1
 107
 108 #if CONFIG_K8_REV_F_SUPPORT == 0
 109                 /* Only e0 later suupport 1GHz HT. */
 110                 if (is_cpu_pre_e0())
 111                         freq_cap &= ~(1 << HT_FREQ_1000Mhz);
 112 #endif
 113
 114 #else
 115                 freq_cap &= ~(1 << HT_FREQ_1000Mhz);
 116 #endif
 117         }
 118
 119         return freq_cap;
 120 }
 121 #endif
 122
 123 struct ht_link {
 124         struct device *dev;
 125         unsigned pos;
 126         unsigned char ctrl_off, config_off, freq_off, freq_cap_off;
 127 };
 128
 129 static int ht_setup_link(struct ht_link *prev, device_t dev, unsigned pos)
 130 {
 131 #if OPT_HT_LINK == 1
 132         static const u8 link_width_to_pow2[] = { 3, 4, 0, 5, 1, 2, 0, 0 };
 133         static const u8 pow2_to_link_width[] = { 7, 4, 5, 0, 1, 3 };
 134         unsigned present_width_cap, upstream_width_cap;
 135         unsigned present_freq_cap, upstream_freq_cap;
 136         unsigned ln_present_width_in, ln_upstream_width_in;
 137         unsigned ln_present_width_out, ln_upstream_width_out;
 138         unsigned freq, old_freq;
 139         unsigned present_width, upstream_width, old_width;
 140 #endif
 141         struct ht_link cur[1];
 142         int reset_needed;
 143         int linkb_to_host;
 144
 145         /* Set the hypertransport link width and frequency. */
 146         reset_needed = 0;
 147         /*
 148          * See which side of the device our previous write to set the unitid
 149          * came from.
 150          */
 151         cur->dev = dev;
 152         cur->pos = pos;
 153         linkb_to_host =
 154           (pci_read_config16(cur->dev, cur->pos + PCI_CAP_FLAGS) >> 10) & 1;
 155
 156         if (!linkb_to_host) {
 157                 cur->ctrl_off     = PCI_HT_CAP_SLAVE_CTRL0;
 158                 cur->config_off   = PCI_HT_CAP_SLAVE_WIDTH0;
 159                 cur->freq_off     = PCI_HT_CAP_SLAVE_FREQ0;
 160                 cur->freq_cap_off = PCI_HT_CAP_SLAVE_FREQ_CAP0;
 161         } else {
 162                 cur->ctrl_off     = PCI_HT_CAP_SLAVE_CTRL1;
 163                 cur->config_off   = PCI_HT_CAP_SLAVE_WIDTH1;
 164                 cur->freq_off     = PCI_HT_CAP_SLAVE_FREQ1;
 165                 cur->freq_cap_off = PCI_HT_CAP_SLAVE_FREQ_CAP1;
 166         }
 167
 168 #if OPT_HT_LINK == 1
 169         /* Read the capabilities. */
 170         present_freq_cap =
 171                 ht_read_freq_cap(cur->dev, cur->pos + cur->freq_cap_off);
 172         upstream_freq_cap =
 173                 ht_read_freq_cap(prev->dev, prev->pos + prev->freq_cap_off);
 174         present_width_cap =
 175                 pci_read_config8(cur->dev, cur->pos + cur->config_off);
 176         upstream_width_cap =
 177                 pci_read_config8(prev->dev, prev->pos + prev->config_off);
 178
 179         /* Calculate the highest useable frequency. */
 180         freq = log2(present_freq_cap & upstream_freq_cap);
 181
 182         /* Calculate the highest width. */
 183         ln_upstream_width_in = link_width_to_pow2[upstream_width_cap & 7];
 184         ln_present_width_out = link_width_to_pow2[(present_width_cap >> 4) & 7];
 185         if (ln_upstream_width_in > ln_present_width_out)
 186                 ln_upstream_width_in = ln_present_width_out;
 187         upstream_width = pow2_to_link_width[ln_upstream_width_in];
 188         present_width  = pow2_to_link_width[ln_upstream_width_in] << 4;
 189
 190         ln_upstream_width_out =
 191                 link_width_to_pow2[(upstream_width_cap >> 4) & 7];
 192         ln_present_width_in = link_width_to_pow2[present_width_cap & 7];
 193         if (ln_upstream_width_out > ln_present_width_in)
 194                 ln_upstream_width_out = ln_present_width_in;
 195         upstream_width |= pow2_to_link_width[ln_upstream_width_out] << 4;
 196         present_width  |= pow2_to_link_width[ln_upstream_width_out];
 197
 198         /* Set the current device. */
 199         old_freq = pci_read_config8(cur->dev, cur->pos + cur->freq_off);
 200         old_freq &= 0x0f;
 201         if (freq != old_freq) {
 202                 unsigned new_freq;
 203                 pci_write_config8(cur->dev, cur->pos + cur->freq_off, freq);
 204                 reset_needed = 1;
 205                 printk(BIOS_SPEW, "HyperT FreqP old %x new %x\n",old_freq,freq);
 206                 new_freq = pci_read_config8(cur->dev, cur->pos + cur->freq_off);
 207                 new_freq &= 0x0f;
 208                 if (new_freq != freq) {
 209                         printk(BIOS_ERR, "%s Hypertransport frequency would "
 210                                "not set. Wanted: %x, got: %x\n",
 211                                dev_path(dev), freq, new_freq);
 212                 }
 213         }
 214         old_width = pci_read_config8(cur->dev, cur->pos + cur->config_off + 1);
 215         if (present_width != old_width) {
 216                 unsigned new_width;
 217                 pci_write_config8(cur->dev, cur->pos + cur->config_off + 1,
 218                                   present_width);
 219                 reset_needed = 1;
 220                 printk(BIOS_SPEW, "HyperT widthP old %x new %x\n",
 221                        old_width, present_width);
 222                 new_width = pci_read_config8(cur->dev,
 223                                              cur->pos + cur->config_off + 1);
 224                 if (new_width != present_width) {
 225                         printk(BIOS_ERR, "%s Hypertransport width would not "
 226                                "set. Wanted: %x, got: %x\n",
 227                                dev_path(dev), present_width, new_width);
 228                 }
 229         }
 230
 231         /* Set the upstream device. */
 232         old_freq = pci_read_config8(prev->dev, prev->pos + prev->freq_off);
 233         old_freq &= 0x0f;
 234         if (freq != old_freq) {
 235                 unsigned new_freq;
 236                 pci_write_config8(prev->dev, prev->pos + prev->freq_off, freq);
 237                 reset_needed = 1;
 238                 printk(BIOS_SPEW, "HyperT freqU old %x new %x\n",
 239                        old_freq, freq);
 240                 new_freq =
 241                   pci_read_config8(prev->dev, prev->pos + prev->freq_off);
 242                 new_freq &= 0x0f;
 243                 if (new_freq != freq) {
 244                         printk(BIOS_ERR, "%s Hypertransport frequency would "
 245                                "not set. Wanted: %x, got: %x\n",
 246                                dev_path(prev->dev), freq, new_freq);
 247                 }
 248         }
 249         old_width =
 250                 pci_read_config8(prev->dev, prev->pos + prev->config_off + 1);
 251         if (upstream_width != old_width) {
 252                 unsigned new_width;
 253                 pci_write_config8(prev->dev, prev->pos + prev->config_off + 1,
 254                                   upstream_width);
 255                 reset_needed = 1;
 256                 printk(BIOS_SPEW, "HyperT widthU old %x new %x\n", old_width,
 257                        upstream_width);
 258                 new_width = pci_read_config8(prev->dev,
 259                                              prev->pos + prev->config_off + 1);
 260                 if (new_width != upstream_width) {
 261                         printk(BIOS_ERR, "%s Hypertransport width would not "
 262                                "set. Wanted: %x, got: %x\n",
 263                                dev_path(prev->dev), upstream_width, new_width);
 264                 }
 265         }
 266 #endif
 267
 268         /*
 269          * Remember the current link as the previous link, but look at the
 270          * other offsets.
 271          */
 272         prev->dev = cur->dev;
 273         prev->pos = cur->pos;
 274         if (cur->ctrl_off == PCI_HT_CAP_SLAVE_CTRL0) {
 275                 prev->ctrl_off     = PCI_HT_CAP_SLAVE_CTRL1;
 276                 prev->config_off   = PCI_HT_CAP_SLAVE_WIDTH1;
 277                 prev->freq_off     = PCI_HT_CAP_SLAVE_FREQ1;
 278                 prev->freq_cap_off = PCI_HT_CAP_SLAVE_FREQ_CAP1;
 279         } else {
 280                 prev->ctrl_off     = PCI_HT_CAP_SLAVE_CTRL0;
 281                 prev->config_off   = PCI_HT_CAP_SLAVE_WIDTH0;
 282                 prev->freq_off     = PCI_HT_CAP_SLAVE_FREQ0;
 283                 prev->freq_cap_off = PCI_HT_CAP_SLAVE_FREQ_CAP0;
 284         }
 285
 286         return reset_needed;
 287 }
 288
 289 static unsigned ht_lookup_slave_capability(struct device *dev)
 290 {
 291         unsigned pos;
 292
 293         pos = 0;
 294         do {
 295                 pos = pci_find_next_capability(dev, PCI_CAP_ID_HT, pos);
 296                 if (pos) {
 297                         u16 flags;
 298                         flags = pci_read_config16(dev, pos + PCI_CAP_FLAGS);
 299                         printk(BIOS_SPEW, "flags: 0x%04x\n", flags);
 300                         if ((flags >> 13) == 0) {
 301                                 /* Entry is a slave secondary, success... */
 302                                 break;
 303                         }
 304                 }
 305         } while (pos);
 306
 307         return pos;
 308 }
 309
 310 static void ht_collapse_early_enumeration(struct bus *bus,
 311                                           unsigned offset_unitid)
 312 {
 313         unsigned int devfn;
 314         struct ht_link prev;
 315         u16 ctrl;
 316
 317         /* Initialize the hypertransport enumeration state. */
 318         prev.dev = bus->dev;
 319         prev.pos = bus->cap;
 320         prev.ctrl_off     = PCI_HT_CAP_HOST_CTRL;
 321         prev.config_off   = PCI_HT_CAP_HOST_WIDTH;
 322         prev.freq_off     = PCI_HT_CAP_HOST_FREQ;
 323         prev.freq_cap_off = PCI_HT_CAP_HOST_FREQ_CAP;
 324
 325         /* Wait until the link initialization is complete. */
 326         do {
 327                 ctrl = pci_read_config16(prev.dev, prev.pos + prev.ctrl_off);
 328
 329                 /* Is this the end of the hypertransport chain? */
 330                 if (ctrl & (1 << 6))
 331                         return;
 332
 333                 /* Has the link failed? */
 334                 if (ctrl & (1 << 4)) {
 335                         /*
 336                          * Either the link has failed, or we have a CRC error.
 337                          * Sometimes this can happen due to link retrain, so
 338                          * lets knock it down and see if its transient.
 339                          */
 340                         ctrl |= ((1 << 4) | (1 << 8)); /* Link fail + CRC */
 341                         pci_write_config16(prev.dev, prev.pos + prev.ctrl_off,
 342                                            ctrl);
 343                         ctrl = pci_read_config16(prev.dev,
 344                                                  prev.pos + prev.ctrl_off);
 345                         if (ctrl & ((1 << 4) | (1 << 8))) {
 346                                 printk(BIOS_ALERT, "Detected error on "
 347                                        "Hypertransport link\n");
 348                                 return;
 349                         }
 350                 }
 351         } while ((ctrl & (1 << 5)) == 0);
 352
 353         /* Actually, only for one HT device HT chain, and unitid is 0. */
 354 #if CONFIG_HT_CHAIN_UNITID_BASE == 0
 355         if (offset_unitid)
 356                 return;
 357 #endif
 358
 359         /* Check if is already collapsed. */
 360         if ((!offset_unitid) || (offset_unitid
 361             && (!((CONFIG_HT_CHAIN_END_UNITID_BASE == 0)
 362             && (CONFIG_HT_CHAIN_END_UNITID_BASE
 363             < CONFIG_HT_CHAIN_UNITID_BASE))))) {
 364
 365                 struct device dummy;
 366                 u32 id;
 367
 368                 dummy.bus = bus;
 369                 dummy.path.type = DEVICE_PATH_PCI;
 370                 dummy.path.pci.devfn = PCI_DEVFN(0, 0);
 371
 372                 id = pci_read_config32(&dummy, PCI_VENDOR_ID);
 373                 if (!((id == 0xffffffff) || (id == 0x00000000)
 374                     || (id == 0x0000ffff) || (id == 0xffff0000))) {
 375                         return;
 376                 }
 377         }
 378
 379         /* Spin through the devices and collapse any early HT enumeration. */
 380         for (devfn = PCI_DEVFN(1, 0); devfn <= 0xff; devfn += 8) {
 381                 struct device dummy;
 382                 u32 id;
 383                 unsigned pos, flags;
 384
 385                 dummy.bus = bus;
 386                 dummy.path.type = DEVICE_PATH_PCI;
 387                 dummy.path.pci.devfn = devfn;
 388
 389                 id = pci_read_config32(&dummy, PCI_VENDOR_ID);
 390                 if ((id == 0xffffffff) || (id == 0x00000000)
 391                     || (id == 0x0000ffff) || (id == 0xffff0000)) {
 392                         continue;
 393                 }
 394
 395                 dummy.vendor = id & 0xffff;
 396                 dummy.device = (id >> 16) & 0xffff;
 397                 dummy.hdr_type = pci_read_config8(&dummy, PCI_HEADER_TYPE);
 398
 399                 pos = ht_lookup_slave_capability(&dummy);
 400                 if (!pos)
 401                         continue;
 402
 403                 /* Clear the unitid. */
 404                 flags = pci_read_config16(&dummy, pos + PCI_CAP_FLAGS);
 405                 flags &= ~0x1f;
 406                 pci_write_config16(&dummy, pos + PCI_CAP_FLAGS, flags);
 407                 printk(BIOS_SPEW, "Collapsing %s [%04x/%04x]\n",
 408                        dev_path(&dummy), dummy.vendor, dummy.device);
 409         }
 410 }
 411
 412 unsigned int hypertransport_scan_chain(struct bus *bus, unsigned min_devfn,
 413                                        unsigned max_devfn, unsigned int max,
 414                                        unsigned *ht_unitid_base,
 415                                        unsigned offset_unitid)
 416 {
 417         /*
 418          * Even CONFIG_HT_CHAIN_UNITID_BASE == 0, we still can go through this
 419          * function, because of end_of_chain check. Also, we need it to
 420          * optimize link.
 421          */
 422         unsigned int next_unitid, last_unitid, min_unitid, max_unitid;
 423         device_t old_devices, dev, func, last_func = 0;
 424         struct ht_link prev;
 425         int ht_dev_num = 0;
 426
 427         min_unitid = (offset_unitid) ? CONFIG_HT_CHAIN_UNITID_BASE : 1;
 428
 429 #if CONFIG_HT_CHAIN_END_UNITID_BASE != 0x20
 430         /*
 431          * Let's record the device of last HT device, so we can set the unitid
 432          * to CONFIG_HT_CHAIN_END_UNITID_BASE.
 433          */
 434         unsigned int real_last_unitid = 0, end_used = 0;
 435         u8 real_last_pos = 0;
 436         device_t real_last_dev = NULL;
 437 #endif
 438
 439         printk(BIOS_INFO, "%s: before ht_collapse_early_enumeration\n", __func__);
 440         /* Restore the hypertransport chain to it's unitialized state. */
 441         ht_collapse_early_enumeration(bus, offset_unitid);
 442         printk(BIOS_INFO, "%s: after  ht_collapse_early_enumeration\n", __func__);
 443
 444         /* See which static device nodes I have. */
 445         old_devices = bus->children;
 446         bus->children = 0;
 447
 448         /* Initialize the hypertransport enumeration state. */
 449         prev.dev = bus->dev;
 450         prev.pos = bus->cap;
 451
 452         prev.ctrl_off     = PCI_HT_CAP_HOST_CTRL;
 453         prev.config_off   = PCI_HT_CAP_HOST_WIDTH;
 454         prev.freq_off     = PCI_HT_CAP_HOST_FREQ;
 455         prev.freq_cap_off = PCI_HT_CAP_HOST_FREQ_CAP;
 456
 457         /* If present, assign unitid to a hypertransport chain. */
 458         last_unitid = min_unitid -1;
 459         max_unitid = next_unitid = min_unitid;
 460         do {
 461                 u8 pos;
 462                 u16 flags, ctrl;
 463                 unsigned int count, static_count;
 464
 465                 last_unitid = next_unitid;
 466
 467                 /* Wait until the link initialization is complete. */
 468                 do {
 469                         ctrl = pci_read_config16(prev.dev,
 470                                                  prev.pos + prev.ctrl_off);
 471
 472                         /* End of chain? */
 473                         if (ctrl & (1 << 6))
 474                                 goto end_of_chain;
 475
 476                         if (ctrl & ((1 << 4) | (1 << 8))) {
 477                                 /*
 478                                  * Either the link has failed, or we have a CRC
 479                                  * error. Sometimes this can happen due to link
 480                                  * retrain, so lets knock it down and see if
 481                                  * it's transient.
 482                                  */
 483                                 ctrl |= ((1 << 4) | (1 <<8)); // Link fail + CRC
 484                                 pci_write_config16(prev.dev,
 485                                         prev.pos + prev.ctrl_off, ctrl);
 486                                 ctrl = pci_read_config16(prev.dev,
 487                                                 prev.pos + prev.ctrl_off);
 488                                 if (ctrl & ((1 << 4) | (1 << 8))) {
 489                                         printk(BIOS_ALERT, "Detected error on "
 490                                                "hypertransport link\n");
 491                                         goto end_of_chain;
 492                                 }
 493                         }
 494                 } while ((ctrl & (1 << 5)) == 0);
 495
 496
 497                 printk(BIOS_INFO, "%s: before ht_scan_get_devs\n", __func__);
 498                 /* Get and setup the device_structure. */
 499                 dev = ht_scan_get_devs(&old_devices);
 500                 printk(BIOS_INFO, "%s: after  ht_scan_get_devs\n", __func__);
 501
 502                 /* See if a device is present and setup the device structure. */
 503                 printk(BIOS_INFO, "%s: before pci_probe_dev\n", __func__);
 504                 dev = pci_probe_dev(dev, bus, 0);
 505                 printk(BIOS_INFO, "%s: after  pci_probe_dev\n", __func__);
 506                 if (!dev || !dev->enabled)
 507                         break;
 508
 509                 /* Find the hypertransport link capability. */
 510                 printk(BIOS_INFO, "%s: before ht_lookup_slave_capability\n", __func__);
 511                 pos = ht_lookup_slave_capability(dev);
 512                 printk(BIOS_INFO, "%s: after  ht_lookup_slave_capability\n", __func__);
 513                 if (pos == 0) {
 514                         printk(BIOS_ERR, "%s Hypertransport link capability "
 515                                "not found", dev_path(dev));
 516                         break;
 517                 }
 518
 519                 /* Update the unitid of the current device. */
 520                 flags = pci_read_config16(dev, pos + PCI_CAP_FLAGS);
 521
 522                 /*
 523                  * If the devices has a unitid set and is at devfn 0 we are
 524                  * done. This can happen with shadow hypertransport devices,
 525                  * or if we have reached the bottom of a HT device chain.
 526                  */
 527                 if (flags & 0x1f)
 528                         break;
 529
 530                 flags &= ~0x1f; /* Mask out base Unit ID. */
 531
 532                 count = (flags >> 5) & 0x1f; /* Het unit count. */
 533
 534 #if CONFIG_HT_CHAIN_END_UNITID_BASE != 0x20
 535                 if (offset_unitid) {
 536                         /* max_devfn will be (0x17<<3)|7 or (0x1f<<3)|7. */
 537                         if (next_unitid > (max_devfn >> 3)) {
 538                                 if (!end_used) {
 539                                         next_unitid =
 540                                           CONFIG_HT_CHAIN_END_UNITID_BASE;
 541                                         end_used = 1;
 542                                 } else {
 543                                         goto end_of_chain;
 544                                 }
 545                         }
 546                 }
 547 #endif
 548
 549                 flags |= next_unitid & 0x1f;
 550                 pci_write_config16(dev, pos + PCI_CAP_FLAGS, flags);
 551
 552                 /* Update the unitid in the device structure. */
 553                 static_count = 1;
 554                 for (func = dev; func; func = func->sibling) {
 555                         func->path.pci.devfn += (next_unitid << 3);
 556                         static_count = (func->path.pci.devfn >> 3)
 557                                         - (dev->path.pci.devfn >> 3) + 1;
 558                         last_func = func;
 559                 }
 560
 561                 /* Compute the number of unitids consumed. */
 562                 printk(BIOS_SPEW, "%s count: %04x static_count: %04x\n",
 563                        dev_path(dev), count, static_count);
 564                 if (count < static_count)
 565                         count = static_count;
 566
 567                 /* Update the unitid of the next device. */
 568                 ht_unitid_base[ht_dev_num] = next_unitid;
 569                 ht_dev_num++;
 570
 571 #if CONFIG_HT_CHAIN_END_UNITID_BASE != 0x20
 572                 if (offset_unitid) {
 573                         real_last_pos = pos;
 574                         real_last_unitid = next_unitid;
 575                         real_last_dev = dev;
 576                 }
 577 #endif
 578                 next_unitid += count;
 579                 if (next_unitid > max_unitid)
 580                         max_unitid = next_unitid;
 581
 582                 /* Setup the hypetransport link. */
 583                 printk(BIOS_INFO, "%s: before ht_setup_link\n", __func__);
 584                 bus->reset_needed |= ht_setup_link(&prev, dev, pos);
 585                 printk(BIOS_INFO, "%s: after  ht_setup_link\n", __func__);
 586
 587                 printk(BIOS_DEBUG, "%s [%04x/%04x] %s next_unitid: %04x\n",
 588                        dev_path(dev), dev->vendor, dev->device,
 589                        (dev->enabled? "enabled" : "disabled"), next_unitid);
 590
 591         } while (last_unitid != next_unitid);
 592
 593 end_of_chain:
 594
 595         printk(BIOS_INFO, "%s: end_of_chain.  w00t!\n", __func__);
 596 #if OPT_HT_LINK == 1
 597         if (bus->reset_needed)
 598                 printk(BIOS_INFO, "HyperT reset needed\n");
 599         else
 600                 printk(BIOS_DEBUG, "HyperT reset not needed\n");
 601 #endif
 602
 603 #if CONFIG_HT_CHAIN_END_UNITID_BASE != 0x20
 604         if (offset_unitid && (ht_dev_num > 1)
 605             && (real_last_unitid != CONFIG_HT_CHAIN_END_UNITID_BASE)
 606             && !end_used) {
 607                 u16 flags;
 608                 flags = pci_read_config16(real_last_dev,
 609                                           real_last_pos + PCI_CAP_FLAGS);
 610                 flags &= ~0x1f;
 611                 flags |= CONFIG_HT_CHAIN_END_UNITID_BASE & 0x1f;
 612                 pci_write_config16(real_last_dev,
 613                                    real_last_pos + PCI_CAP_FLAGS, flags);
 614
 615                 for (func = real_last_dev; func; func = func->sibling) {
 616                         func->path.pci.devfn -= ((real_last_unitid
 617                                 - CONFIG_HT_CHAIN_END_UNITID_BASE) << 3);
 618                         last_func = func;
 619                 }
 620
 621                 /* Update last one. */
 622                 ht_unitid_base[ht_dev_num-1] = CONFIG_HT_CHAIN_END_UNITID_BASE;
 623
 624                 printk(BIOS_DEBUG, " unitid: %04x --> %04x\n",
 625                        real_last_unitid, CONFIG_HT_CHAIN_END_UNITID_BASE);
 626         }
 627 #endif
 628         next_unitid = max_unitid;
 629
 630         if (next_unitid > 0x20)
 631                 next_unitid = 0x20;
 632
 633         if ((bus->secondary == 0) && (next_unitid > 0x18))
 634                 next_unitid = 0x18; /* Avoid K8 on bus 0. */
 635
 636         /*
 637          * Die if any leftover static devices are are found. There's probably
 638          * a problem in devicetree.cb.
 639          */
 640         if (old_devices) {
 641                 device_t left;
 642                 for (left = old_devices; left; left = left->sibling)
 643                         printk(BIOS_DEBUG, "%s\n", dev_path(left));
 644
 645                 printk(BIOS_ERR, "HT: Leftover static devices. "
 646                        "Check your devicetree.cb\n");
 647
 648                 /*
 649                  * Put back the leftover static device, and let pci_scan_bus()
 650                  * disable it.
 651                  */
 652                 if (last_func && !last_func->sibling)
 653                         last_func->sibling = old_devices;
 654         }
 655
 656         printk(BIOS_INFO, "%s: before pci_scan_bus!\n", __func__);
 657         /* Now that nothing is overlapping it is safe to scan the children. */
 658         max = pci_scan_bus(bus, 0x00, ((next_unitid - 1) << 3) | 7, max);
 659         printk(BIOS_INFO, "%s: after  pci_scan_bus!\n", __func__);
 660         return max;
 661 }
 662
 663 /**
 664  * Scan a PCI bridge and the buses behind the bridge.
 665  *
 666  * Determine the existence of buses behind the bridge. Set up the bridge
 667  * according to the result of the scan.
 668  *
 669  * This function is the default scan_bus() method for PCI bridge devices.
 670  *
 671  * @param bus TODO
 672  * @param min_devfn TODO
 673  * @param max_devfn TODO
 674  * @param max The highest bus number assgined up to now.
 675  * @return The maximum bus number found, after scanning all subordinate busses.
 676  */
 677 static unsigned int hypertransport_scan_chain_x(struct bus *bus,
 678         unsigned int min_devfn, unsigned int max_devfn, unsigned int max)
 679 {
 680         unsigned int ht_unitid_base[4];
 681         unsigned int offset_unitid = 1;
 682         return hypertransport_scan_chain(bus, min_devfn, max_devfn, max,
 683                                          ht_unitid_base, offset_unitid);
 684 }
 685
 686 unsigned int ht_scan_bridge(struct device *dev, unsigned int max)
 687 {
 688         return do_pci_scan_bridge(dev, max, hypertransport_scan_chain_x);
 689 }
 690
 691 /** Default device operations for hypertransport bridges */
 692 static struct pci_operations ht_bus_ops_pci = {
 693         .set_subsystem = 0,
 694 };
 695
 696 struct device_operations default_ht_ops_bus = {
 697         .read_resources   = pci_bus_read_resources,
 698         .set_resources    = pci_dev_set_resources,
 699         .enable_resources = pci_bus_enable_resources,
 700         .init             = 0,
 701         .scan_bus         = ht_scan_bridge,
 702         .enable           = 0,
 703         .reset_bus        = pci_bus_reset,
 704         .ops_pci          = &ht_bus_ops_pci,
 705 };