1 files changed, 692 insertions, 0 deletions

diff --git a/src/device/hypertransport.c b/src/device/hypertransport.c
new file mode 100644
index 0000000000..a6320fe666
--- /dev/null
+++ b/src/device/hypertransport.c
@@ -0,0 +1,692 @@
+/*
+ * This file is part of the coreboot 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
+ */
+
+#include <lib.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>
+
+/*
+ * The hypertransport link is already optimized in pre-RAM code so don't do
+ * it again.
+ */
+#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.pci.devfn > last->path.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 CONFIG_K8_HT_FREQ_1G_SUPPORT
+
+#if !CONFIG_K8_REV_F_SUPPORT
+		/* Only e0 later suupport 1GHz HT. */
+		if (is_cpu_pre_e0())
+			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)
+{
+#if OPT_HT_LINK == 1
+	static const u8 link_width_to_pow2[] = { 3, 4, 0, 5, 1, 2, 0, 0 };
+	static const u8 pow2_to_link_width[] = { 7, 4, 5, 0, 1, 3 };
+	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;
+#endif
+	struct ht_link cur[1];
+	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(BIOS_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(BIOS_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(BIOS_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(BIOS_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(BIOS_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(BIOS_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(BIOS_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(BIOS_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) {
+			u16 flags;
+			flags = pci_read_config16(dev, pos + PCI_CAP_FLAGS);
+			printk(BIOS_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;
+	u16 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(BIOS_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 !CONFIG_HT_CHAIN_UNITID_BASE
+	if (offset_unitid)
+		return;
+#endif
+
+	/* Check if is already collapsed. */
+	if ((!offset_unitid) || (offset_unitid
+	    && (!((CONFIG_HT_CHAIN_END_UNITID_BASE == 0)
+	    && (CONFIG_HT_CHAIN_END_UNITID_BASE
+	    < CONFIG_HT_CHAIN_UNITID_BASE))))) {
+
+		struct device dummy;
+		u32 id;
+
+		dummy.bus = bus;
+		dummy.path.type = DEVICE_PATH_PCI;
+		dummy.path.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 HT enumeration. */
+	for (devfn = PCI_DEVFN(1, 0); devfn <= 0xff; devfn += 8) {
+		struct device dummy;
+		u32 id;
+		unsigned pos, flags;
+
+		dummy.bus = bus;
+		dummy.path.type = DEVICE_PATH_PCI;
+		dummy.path.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(BIOS_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 CONFIG_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 int next_unitid, last_unitid, min_unitid, max_unitid;
+	device_t old_devices, dev, func, last_func = 0;
+	struct ht_link prev;
+	int ht_dev_num = 0;
+
+	min_unitid = (offset_unitid) ? CONFIG_HT_CHAIN_UNITID_BASE : 1;
+
+#if CONFIG_HT_CHAIN_END_UNITID_BASE != 0x20
+        /*
+	 * Let's record the device of last HT device, so we can set the unitid
+	 * to CONFIG_HT_CHAIN_END_UNITID_BASE.
+	 */
+	unsigned int real_last_unitid = 0, end_used = 0;
+	u8 real_last_pos = 0;
+	device_t real_last_dev = NULL;
+#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;
+	max_unitid = next_unitid = min_unitid;
+	do {
+		u8 pos;
+		u16 flags, ctrl;
+		unsigned int count, static_count;
+
+		last_unitid = next_unitid;
+
+		/* Wait until the link initialization is complete. */
+		do {
+			ctrl = pci_read_config16(prev.dev,
+						 prev.pos + prev.ctrl_off);
+
+			/* End of chain? */
+			if (ctrl & (1 << 6))
+				goto 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
+				 * it's 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(BIOS_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(BIOS_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 HT device chain.
+		 */
+		if (flags & 0x1f)
+			break;
+
+		flags &= ~0x1f; /* Mask out base Unit ID. */
+
+		count = (flags >> 5) & 0x1f; /* Het unit count. */
+
+#if CONFIG_HT_CHAIN_END_UNITID_BASE != 0x20
+		if (offset_unitid) {
+			/* max_devfn will be (0x17<<3)|7 or (0x1f<<3)|7. */
+			if (next_unitid > (max_devfn >> 3)) {
+				if (!end_used) {
+			                next_unitid =
+					  CONFIG_HT_CHAIN_END_UNITID_BASE;
+					end_used = 1;
+				} else {
+					goto end_of_chain;
+				}
+			}
+		}
+#endif
+
+		flags |= next_unitid & 0x1f;
+		pci_write_config16(dev, pos + PCI_CAP_FLAGS, flags);
+
+		/* Update the unitid in the device structure. */
+		static_count = 1;
+		for (func = dev; func; func = func->sibling) {
+			func->path.pci.devfn += (next_unitid << 3);
+			static_count = (func->path.pci.devfn >> 3)
+				        - (dev->path.pci.devfn >> 3) + 1;
+			last_func = func;
+		}
+
+		/* Compute the number of unitids consumed. */
+		printk(BIOS_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 CONFIG_HT_CHAIN_END_UNITID_BASE != 0x20
+		if (offset_unitid) {
+			real_last_pos = pos;
+			real_last_unitid = next_unitid;
+			real_last_dev = dev;
+		}
+#endif
+		next_unitid += count;
+		if (next_unitid > max_unitid)
+			max_unitid = next_unitid;
+
+		/* Setup the hypetransport link. */
+		bus->reset_needed |= ht_setup_link(&prev, dev, pos);
+
+		printk(BIOS_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);
+
+end_of_chain:
+
+#if OPT_HT_LINK == 1
+	if (bus->reset_needed)
+		printk(BIOS_INFO, "HyperT reset needed\n");
+	else
+		printk(BIOS_DEBUG, "HyperT reset not needed\n");
+#endif
+
+#if CONFIG_HT_CHAIN_END_UNITID_BASE != 0x20
+	if (offset_unitid && (ht_dev_num > 1)
+	    && (real_last_unitid != CONFIG_HT_CHAIN_END_UNITID_BASE)
+	    && !end_used) {
+		u16 flags;
+		flags = pci_read_config16(real_last_dev,
+					  real_last_pos + PCI_CAP_FLAGS);
+		flags &= ~0x1f;
+		flags |= CONFIG_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.pci.devfn -= ((real_last_unitid
+				- CONFIG_HT_CHAIN_END_UNITID_BASE) << 3);
+			last_func = func;
+		}
+
+		/* Update last one. */
+		ht_unitid_base[ht_dev_num-1] = CONFIG_HT_CHAIN_END_UNITID_BASE;
+
+		printk(BIOS_DEBUG, " unitid: %04x --> %04x\n",
+		       real_last_unitid, CONFIG_HT_CHAIN_END_UNITID_BASE);
+	}
+#endif
+	next_unitid = max_unitid;
+
+	if (next_unitid > 0x20)
+		next_unitid = 0x20;
+
+	if ((bus->secondary == 0) && (next_unitid > 0x18))
+		next_unitid = 0x18; /* Avoid K8 on bus 0. */
+
+	/*
+	 * Die if any leftover static devices are are found. There's probably
+	 * a problem in devicetree.cb.
+	 */
+	if (old_devices) {
+		device_t left;
+		for (left = old_devices; left; left = left->sibling)
+			printk(BIOS_DEBUG, "%s\n", dev_path(left));
+
+		printk(BIOS_ERR, "HT: Leftover static devices. "
+		       "Check your devicetree.cb\n");
+
+		/*
+		 * Put back the leftover static device, and let pci_scan_bus()
+		 * disable it.
+		 */
+		if (last_func && !last_func->sibling)
+			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 - 1) << 3) | 7, max);
+	return max;
+}
+
+/**
+ * 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 bus TODO
+ * @param min_devfn TODO
+ * @param max_devfn TODO
+ * @param max The highest bus number assgined up to now.
+ * @return The maximum bus number found, after scanning all subordinate busses.
+ */
+static unsigned int hypertransport_scan_chain_x(struct bus *bus,
+	unsigned int min_devfn, unsigned int max_devfn, unsigned int max)
+{
+	unsigned int ht_unitid_base[4];
+	unsigned int 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,
+};