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-rw-r--r--src/devices/hypertransport.c61
-rw-r--r--src/northbridge/amd/amdk8/early_ht.c106
-rw-r--r--src/northbridge/amd/amdk8/incoherent_ht.c72
-rw-r--r--src/northbridge/amd/amdk8/northbridge.c16
-rw-r--r--src/southbridge/nvidia/mcp55/mcp55_enable_rom.c2
-rw-r--r--src/southbridge/nvidia/mcp55/mcp55_enable_usbdebug_direct.c2
6 files changed, 144 insertions, 115 deletions
diff --git a/src/devices/hypertransport.c b/src/devices/hypertransport.c
index d1e3468874..9846794edd 100644
--- a/src/devices/hypertransport.c
+++ b/src/devices/hypertransport.c
@@ -383,14 +383,14 @@ unsigned int hypertransport_scan_chain(struct bus *bus,
struct ht_link prev;
device_t last_func = 0;
int ht_dev_num = 0;
- unsigned temp_unitid;
- unsigned not_use_count;
+ unsigned max_unitid;
-#if HT_CHAIN_END_UNITID_BASE < HT_CHAIN_UNITID_BASE
+#if HT_CHAIN_END_UNITID_BASE != 0x20
//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;
+ unsigned end_used = 0;
#endif
/* Restore the hypertransport chain to it's unitialized state */
@@ -410,7 +410,7 @@ unsigned int hypertransport_scan_chain(struct bus *bus,
/* If present assign unitid to a hypertransport chain */
last_unitid = min_unitid -1;
- next_unitid = min_unitid;
+ max_unitid = next_unitid = min_unitid;
do {
uint8_t pos;
uint16_t flags;
@@ -478,26 +478,27 @@ unsigned int hypertransport_scan_chain(struct bus *bus,
flags &= ~0x1f; /* mask out base Unit ID */
count = (flags >> 5) & 0x1f; /* get unit count */
- not_use_count = 0;
- temp_unitid = next_unitid;
-#if HT_CHAIN_END_UNITID_BASE < HT_CHAIN_UNITID_BASE
+#if HT_CHAIN_END_UNITID_BASE != 0x20
if(offset_unitid) {
- if((next_unitid+count)>=0x20) {
- temp_unitid = HT_CHAIN_END_UNITID_BASE;
- //still use the old next_unitid
- not_use_count = 1;
+ if(next_unitid > (max_devfn>>3)) { // max_devfn will be (0x17<<3)|7 or (0x1f<<3)|7
+ if(!end_used) {
+ next_unitid = HT_CHAIN_END_UNITID_BASE;
+ end_used = 1;
+ } else {
+ goto out;
+ }
}
}
#endif
- flags |= temp_unitid & 0x1f;
+ 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 += (temp_unitid << 3);
+ 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;
@@ -508,20 +509,22 @@ unsigned int hypertransport_scan_chain(struct bus *bus,
if (count < static_count) {
count = static_count;
}
- if(!not_use_count)
- next_unitid += count;
/* Update the Unitid of the next device */
- ht_unitid_base[ht_dev_num] = temp_unitid;
+ ht_unitid_base[ht_dev_num] = next_unitid;
ht_dev_num++;
-#if HT_CHAIN_END_UNITID_BASE < HT_CHAIN_UNITID_BASE
- if(offset_unitid) {
+#if HT_CHAIN_END_UNITID_BASE != 0x20
+ if (offset_unitid) {
real_last_pos = pos;
- real_last_unitid = temp_unitid;
+ 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);
@@ -531,7 +534,8 @@ unsigned int hypertransport_scan_chain(struct bus *bus,
dev->vendor, dev->device,
(dev->enabled? "enabled": "disabled"), next_unitid);
- } while((last_unitid != next_unitid) && (next_unitid <= 0x1f /*(max_devfn >> 3)*/ ));
+ } while (last_unitid != next_unitid);
+ out:
end_of_chain:
#if OPT_HT_LINK == 1
if(bus->reset_needed) {
@@ -542,8 +546,8 @@ unsigned int hypertransport_scan_chain(struct bus *bus,
}
#endif
-#if HT_CHAIN_END_UNITID_BASE < HT_CHAIN_UNITID_BASE
- if(offset_unitid && (ht_dev_num>1) && (real_last_unitid != HT_CHAIN_END_UNITID_BASE) ) {
+#if HT_CHAIN_END_UNITID_BASE != 0x20
+ if(offset_unitid && (ht_dev_num>1) && (real_last_unitid != HT_CHAIN_END_UNITID_BASE) && !end_used) {
uint16_t flags;
int i;
device_t last_func = 0;
@@ -559,15 +563,18 @@ unsigned int hypertransport_scan_chain(struct bus *bus,
ht_unitid_base[ht_dev_num-1] = HT_CHAIN_END_UNITID_BASE; // update last one
- next_unitid = real_last_unitid;
+ printk_debug(" unitid: %04x --> %04x\n",
+ real_last_unitid, HT_CHAIN_END_UNITID_BASE);
+
}
#endif
+ next_unitid = max_unitid;
- if (next_unitid > 0x1f) {
- next_unitid = 0x1f;
+ if (next_unitid > 0x20) {
+ next_unitid = 0x20;
}
- if( (bus->secondary == 0) && (next_unitid > 0x17)) {
- next_unitid = 0x17; /* avoid K8 on bus 0 */
+ if( (bus->secondary == 0) && (next_unitid > 0x18)) {
+ next_unitid = 0x18; /* avoid K8 on bus 0 */
}
/* Die if any leftover Static devices are are found.
diff --git a/src/northbridge/amd/amdk8/early_ht.c b/src/northbridge/amd/amdk8/early_ht.c
index 1a3975a0ea..57830717ed 100644
--- a/src/northbridge/amd/amdk8/early_ht.c
+++ b/src/northbridge/amd/amdk8/early_ht.c
@@ -13,22 +13,23 @@ static void enumerate_ht_chain(void)
* links needs to be programed to point at bus 0.
*/
unsigned next_unitid, last_unitid;
- unsigned temp_unitid;
- unsigned not_use_count;
-#if HT_CHAIN_END_UNITID_BASE < HT_CHAIN_UNITID_BASE
+ device_t dev;
+#if HT_CHAIN_END_UNITID_BASE != 0x20
//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;
int ht_dev_num = 0; // except host_bridge
+ uint8_t end_used = 0;
#endif
+ dev = PCI_DEV(0,0,0);
next_unitid = HT_CHAIN_UNITID_BASE;
do {
uint32_t id;
uint8_t hdr_type, pos;
last_unitid = next_unitid;
- id = pci_read_config32(PCI_DEV(0,0,0), PCI_VENDOR_ID);
+ id = pci_read_config32(dev, PCI_VENDOR_ID);
/* If the chain is enumerated quit */
if (((id & 0xffff) == 0x0000) || ((id & 0xffff) == 0xffff) ||
(((id >> 16) & 0xffff) == 0xffff) ||
@@ -37,73 +38,102 @@ static void enumerate_ht_chain(void)
break;
}
- hdr_type = pci_read_config8(PCI_DEV(0,0,0), PCI_HEADER_TYPE);
+ hdr_type = pci_read_config8(dev, PCI_HEADER_TYPE);
pos = 0;
hdr_type &= 0x7f;
if ((hdr_type == PCI_HEADER_TYPE_NORMAL) ||
(hdr_type == PCI_HEADER_TYPE_BRIDGE))
{
- pos = pci_read_config8(PCI_DEV(0,0,0), PCI_CAPABILITY_LIST);
+ pos = pci_read_config8(dev, PCI_CAPABILITY_LIST);
}
while(pos != 0) {
uint8_t cap;
- cap = pci_read_config8(PCI_DEV(0,0,0), pos + PCI_CAP_LIST_ID);
+ cap = pci_read_config8(dev, pos + PCI_CAP_LIST_ID);
if (cap == PCI_CAP_ID_HT) {
uint16_t flags;
/* Read and write and reread flags so the link
* direction bit is valid.
*/
- flags = pci_read_config16(PCI_DEV(0,0,0), pos + PCI_CAP_FLAGS);
- pci_write_config16(PCI_DEV(0,0,0), pos + PCI_CAP_FLAGS, flags);
- flags = pci_read_config16(PCI_DEV(0,0,0), pos + PCI_CAP_FLAGS);
+ flags = pci_read_config16(dev, pos + PCI_CAP_FLAGS);
+ pci_write_config16(dev, pos + PCI_CAP_FLAGS, flags);
+ flags = pci_read_config16(dev, pos + PCI_CAP_FLAGS);
if ((flags >> 13) == 0) {
unsigned count;
unsigned ctrl, ctrl_off;
+ device_t devx;
- flags &= ~0x1f;
- count = (flags >> 5) & 0x1f;
- not_use_count = 0;
- temp_unitid = next_unitid;
-#if HT_CHAIN_END_UNITID_BASE < HT_CHAIN_UNITID_BASE
- if ( (count + next_unitid) >= 0x20) {
- temp_unitid = HT_CHAIN_END_UNITID_BASE;
- not_use_count = 1;
+#if HT_CHAIN_END_UNITID_BASE != 0x20
+ if(next_unitid>=0x18) { // don't get mask out by k8, at this time BSP, RT is not enabled, it will response from 0x18,0--0x1f.
+ if(!end_used) {
+ next_unitid = HT_CHAIN_END_UNITID_BASE;
+ end_used = 1;
+ } else {
+ goto out;
+ }
}
- real_last_unitid = temp_unitid;
+ real_last_unitid = next_unitid;
real_last_pos = pos;
ht_dev_num++;
#endif
- flags |= temp_unitid & 0x1f;
- if(!not_use_count)
- next_unitid += count;
+ flags &= ~0x1f;
+ flags |= next_unitid & 0x1f;
+ count = (flags >> 5) & 0x1f;
+
+ devx = PCI_DEV(0, next_unitid, 0);
+ pci_write_config16(dev, pos + PCI_CAP_FLAGS, flags);
+
+ next_unitid += count;
+
+ flags = pci_read_config16(devx, pos + PCI_CAP_FLAGS);
/* Test for end of chain */
ctrl_off = ((flags >> 10) & 1)?
- PCI_HT_CAP_SLAVE_CTRL1 : PCI_HT_CAP_SLAVE_CTRL0;
- ctrl = pci_read_config16(PCI_DEV(0,0,0), pos + ctrl_off);
- /* Is this the end of the hypertransport chain.
- * or has the link failed?
- */
- if (ctrl & ((1 << 6)|(1 << 4))) {
- next_unitid = 0x20;
- }
-
- pci_write_config16(PCI_DEV(0, 0, 0), pos + PCI_CAP_FLAGS, flags);
+ PCI_HT_CAP_SLAVE_CTRL0 : PCI_HT_CAP_SLAVE_CTRL1; // another end
+
+ do {
+ ctrl = pci_read_config16(devx, pos + ctrl_off);
+ /* Is this the end of the hypertransport chain? */
+ if (ctrl & (1 << 6)) {
+ goto out;
+ }
+
+ 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(devx, pos + ctrl_off, ctrl);
+ ctrl = pci_read_config16(devx, pos + ctrl_off);
+ if (ctrl & ((1 << 4) | (1 << 8))) {
+ // can not clear the error
+ break;
+ }
+ }
+ } while((ctrl & (1 << 5)) == 0);
+
break;
}
}
- pos = pci_read_config8(PCI_DEV(0, 0, 0), pos + PCI_CAP_LIST_NEXT);
+ pos = pci_read_config8(dev, pos + PCI_CAP_LIST_NEXT);
}
- } while((last_unitid != next_unitid) && (next_unitid <= 0x1f));
+ } while(last_unitid != next_unitid);
+
+out:
+ ;
-#if HT_CHAIN_END_UNITID_BASE < HT_CHAIN_UNITID_BASE
- if((ht_dev_num>1) && (real_last_unitid != HT_CHAIN_END_UNITID_BASE)) {
+#if HT_CHAIN_END_UNITID_BASE != 0x20
+ if((ht_dev_num>1) && (real_last_unitid != HT_CHAIN_END_UNITID_BASE) && !end_used) {
uint16_t flags;
- flags = pci_read_config16(PCI_DEV(0,real_last_unitid,0), real_last_pos + PCI_CAP_FLAGS);
+ dev = PCI_DEV(0,real_last_unitid, 0);
+ flags = pci_read_config16(dev, real_last_pos + PCI_CAP_FLAGS);
flags &= ~0x1f;
flags |= HT_CHAIN_END_UNITID_BASE & 0x1f;
- pci_write_config16(PCI_DEV(0, real_last_unitid, 0), real_last_pos + PCI_CAP_FLAGS, flags);
+ pci_write_config16(dev, real_last_pos + PCI_CAP_FLAGS, flags);
}
#endif
diff --git a/src/northbridge/amd/amdk8/incoherent_ht.c b/src/northbridge/amd/amdk8/incoherent_ht.c
index dff5c9f44f..58f06468ed 100644
--- a/src/northbridge/amd/amdk8/incoherent_ht.c
+++ b/src/northbridge/amd/amdk8/incoherent_ht.c
@@ -314,12 +314,6 @@ static int scan_pci_bus( unsigned bus)
new_bus = bus;
-#if 0
-#if CONFIG_USE_PRINTK_IN_CAR
- printk_debug("bus_num=%02x\r\n", bus);
-#endif
-#endif
-
for (devfn = 0; devfn <= 0xff; devfn++) {
uint8_t hdr_type;
uint16_t class;
@@ -330,14 +324,6 @@ static int scan_pci_bus( unsigned bus)
hdr_type = pci_read_config8(dev, PCI_HEADER_TYPE);
class = pci_read_config16(dev, PCI_CLASS_DEVICE);
-#if 0
-#if CONFIG_USE_PRINTK_IN_CAR
- if(hdr_type !=0xff ) {
- printk_debug("dev=%02x fn=%02x hdr_type=%02x class=%04x\r\n",
- (devfn>>3)& 0x1f, (devfn & 0x7), hdr_type, class);
- }
-#endif
-#endif
switch(hdr_type & 0x7f) { /* header type */
case PCI_HEADER_TYPE_BRIDGE:
if (class != PCI_CLASS_BRIDGE_PCI) goto bad;
@@ -420,18 +406,17 @@ static int ht_setup_chainx(device_t udev, uint8_t upos, uint8_t bus, unsigned of
uint8_t next_unitid, last_unitid;
unsigned uoffs;
- uint8_t temp_unitid;
- unsigned not_use_count;
#if RAMINIT_SYSINFO == 0
int reset_needed = 0;
#endif
-#if HT_CHAIN_END_UNITID_BASE < HT_CHAIN_UNITID_BASE
+#if HT_CHAIN_END_UNITID_BASE != 0x20
//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;
int ht_dev_num = 0;
+ uint8_t end_used = 0;
#endif
uoffs = PCI_HT_HOST_OFFS;
@@ -491,36 +476,36 @@ static int ht_setup_chainx(device_t udev, uint8_t upos, uint8_t bus, unsigned of
break;
}
- /* Update the Unitid of the current device */
- flags = pci_read_config16(dev, pos + PCI_CAP_FLAGS);
- /* Compute the number of unitids consumed */
- count = (flags >> 5) & 0x1f;
- flags &= ~0x1f; /* mask out the base Unit ID */
- not_use_count = 0;
- temp_unitid = next_unitid;
-#if HT_CHAIN_END_UNITID_BASE < HT_CHAIN_UNITID_BASE
+#if HT_CHAIN_END_UNITID_BASE != 0x20
if(offset_unitid) {
- if( (next_unitid + count) >= 0x20) {
- temp_unitid = HT_CHAIN_END_UNITID_BASE;
- // keep to use the old next_unitid
- not_use_count = 1;
+ if(next_unitid>= (bus ? 0x20:0x18) ) {
+ if(!end_used) {
+ next_unitid = HT_CHAIN_END_UNITID_BASE;
+ end_used = 1;
+ } else {
+ goto out;
+ }
+
}
real_last_pos = pos;
- real_last_unitid = temp_unitid;
+ real_last_unitid = next_unitid;
ht_dev_num++;
}
#endif
-
- flags |= temp_unitid & 0x1f;
+ /* Update the Unitid of the current device */
+ flags = pci_read_config16(dev, pos + PCI_CAP_FLAGS);
+ flags &= ~0x1f; /* mask out the base Unit ID */
+ flags |= next_unitid & 0x1f;
pci_write_config16(dev, pos + PCI_CAP_FLAGS, flags);
- /* Note the change in device number */
- dev = PCI_DEV(bus, temp_unitid, 0);
+ /* Compute the number of unitids consumed */
+ count = (flags >> 5) & 0x1f;
- if(!not_use_count)
- next_unitid += count;
+ /* Note the change in device number */
+ dev = PCI_DEV(bus, next_unitid, 0);
+ next_unitid += count;
/* Find which side of the ht link we are on,
* by reading which direction our last write to PCI_CAP_FLAGS
@@ -550,12 +535,13 @@ static int ht_setup_chainx(device_t udev, uint8_t upos, uint8_t bus, unsigned of
upos = pos;
uoffs = ( offs != PCI_HT_SLAVE0_OFFS ) ? PCI_HT_SLAVE0_OFFS : PCI_HT_SLAVE1_OFFS;
- } while((last_unitid != next_unitid) && (next_unitid <= 0x1f));
+ } while (last_unitid != next_unitid );
+out:
end_of_chain: ;
-#if HT_CHAIN_END_UNITID_BASE < HT_CHAIN_UNITID_BASE
- if(offset_unitid && (ht_dev_num>1) && (real_last_unitid != HT_CHAIN_END_UNITID_BASE) ) {
+#if HT_CHAIN_END_UNITID_BASE != 0x20
+ if(offset_unitid && (ht_dev_num>1) && (real_last_unitid != HT_CHAIN_END_UNITID_BASE) && !end_used ) {
uint16_t flags;
int i;
flags = pci_read_config16(PCI_DEV(bus,real_last_unitid,0), real_last_pos + PCI_CAP_FLAGS);
@@ -594,7 +580,7 @@ static int ht_setup_chain(device_t udev, unsigned upos)
#endif
{
unsigned offset_unitid = 0;
-#if HT_CHAIN_UNITID_BASE != 1
+#if ((HT_CHAIN_UNITID_BASE != 1) || (HT_CHAIN_END_UNITID_BASE != 0x20))
offset_unitid = 1;
#endif
@@ -607,7 +593,7 @@ static int ht_setup_chain(device_t udev, unsigned upos)
/* Make certain the HT bus is not enumerated */
ht_collapse_previous_enumeration(0, 0);
-#if HT_CHAIN_UNITID_BASE != 1
+#if ((HT_CHAIN_UNITID_BASE != 1) || (HT_CHAIN_END_UNITID_BASE != 0x20))
offset_unitid = 1;
#endif
@@ -655,7 +641,7 @@ static int optimize_link_read_pointers_chain(uint8_t ht_c_num)
uint8_t val;
unsigned devn = 1;
- #if HT_CHAIN_UNITID_BASE != 1
+ #if ((HT_CHAIN_UNITID_BASE != 1) || (HT_CHAIN_END_UNITID_BASE != 0x20))
#if SB_HT_CHAIN_UNITID_OFFSET_ONLY == 1
if(i==0) // to check if it is sb ht chain
#endif
@@ -788,7 +774,7 @@ static int ht_setup_chains(uint8_t ht_c_num)
pci_write_config32( PCI_DEV(0, devpos,0), regpos , dword);
- #if HT_CHAIN_UNITID_BASE != 1
+ #if ((HT_CHAIN_UNITID_BASE != 1) || (HT_CHAIN_END_UNITID_BASE != 0x20))
#if SB_HT_CHAIN_UNITID_OFFSET_ONLY == 1
if(i==0) // to check if it is sb ht chain
#endif
diff --git a/src/northbridge/amd/amdk8/northbridge.c b/src/northbridge/amd/amdk8/northbridge.c
index b285426e66..dd97ee7d16 100644
--- a/src/northbridge/amd/amdk8/northbridge.c
+++ b/src/northbridge/amd/amdk8/northbridge.c
@@ -111,6 +111,7 @@ static unsigned int amdk8_scan_chain(device_t dev, unsigned nodeid, unsigned lin
unsigned ht_unitid_base[4]; // here assume only 4 HT device on chain
unsigned max_bus;
unsigned min_bus;
+ unsigned max_devfn;
dev->link[link].cap = 0x80 + (link *0x20);
do {
@@ -212,7 +213,13 @@ static unsigned int amdk8_scan_chain(device_t dev, unsigned nodeid, unsigned lin
for(i=0;i<4;i++) {
ht_unitid_base[i] = 0x20;
}
- max = hypertransport_scan_chain(&dev->link[link], 0, 0xbf, max, ht_unitid_base, offset_unitid);
+
+ if (min_bus == 0)
+ max_devfn = (0x17<<3) | 7;
+ else
+ max_devfn = (0x1f<<3) | 7;
+
+ max = hypertransport_scan_chain(&dev->link[link], 0, max_devfn, max, ht_unitid_base, offset_unitid);
/* We know the number of busses behind this bridge. Set the
* subordinate bus number to it's real value
@@ -250,12 +257,10 @@ static unsigned int amdk8_scan_chains(device_t dev, unsigned int max)
unsigned offset_unitid = 0;
nodeid = amdk8_nodeid(dev);
-
-
if(nodeid==0) {
sblink = (pci_read_config32(dev, 0x64)>>8) & 3;
#if SB_HT_CHAIN_ON_BUS0 > 0
- #if HT_CHAIN_UNITID_BASE != 1
+ #if ((HT_CHAIN_UNITID_BASE != 1) || (HT_CHAIN_END_UNITID_BASE != 0x20))
offset_unitid = 1;
#endif
max = amdk8_scan_chain(dev, nodeid, sblink, sblink, max, offset_unitid ); // do sb ht chain at first, in case s2885 put sb chain (8131/8111) on link2, but put 8151 on link0
@@ -267,7 +272,7 @@ static unsigned int amdk8_scan_chains(device_t dev, unsigned int max)
if( (nodeid == 0) && (sblink == link) ) continue; //already done
#endif
offset_unitid = 0;
- #if HT_CHAIN_UNITID_BASE != 1
+ #if ((HT_CHAIN_UNITID_BASE != 1) || (HT_CHAIN_END_UNITID_BASE != 0x20))
#if SB_HT_CHAIN_UNITID_OFFSET_ONLY == 1
if((nodeid == 0) && (sblink == link))
#endif
@@ -276,6 +281,7 @@ static unsigned int amdk8_scan_chains(device_t dev, unsigned int max)
max = amdk8_scan_chain(dev, nodeid, link, sblink, max, offset_unitid);
}
+
return max;
}
diff --git a/src/southbridge/nvidia/mcp55/mcp55_enable_rom.c b/src/southbridge/nvidia/mcp55/mcp55_enable_rom.c
index 6a2697537e..f18edb74a3 100644
--- a/src/southbridge/nvidia/mcp55/mcp55_enable_rom.c
+++ b/src/southbridge/nvidia/mcp55/mcp55_enable_rom.c
@@ -21,7 +21,7 @@
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
-#if HT_CHAIN_END_UNITID_BASE < HT_CHAIN_UNITID_BASE
+#if HT_CHAIN_END_UNITID_BASE != 0x20
#define MCP55_DEVN_BASE HT_CHAIN_END_UNITID_BASE
#else
#define MCP55_DEVN_BASE HT_CHAIN_UNITID_BASE
diff --git a/src/southbridge/nvidia/mcp55/mcp55_enable_usbdebug_direct.c b/src/southbridge/nvidia/mcp55/mcp55_enable_usbdebug_direct.c
index c431724c5c..ac4e42ab8d 100644
--- a/src/southbridge/nvidia/mcp55/mcp55_enable_usbdebug_direct.c
+++ b/src/southbridge/nvidia/mcp55/mcp55_enable_usbdebug_direct.c
@@ -21,7 +21,7 @@
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
-#if HT_CHAIN_END_UNITID_BASE < HT_CHAIN_UNITID_BASE
+#if HT_CHAIN_END_UNITID_BASE != 0x20
#define MCP55_DEVN_BASE HT_CHAIN_END_UNITID_BASE
#else
#define MCP55_DEVN_BASE HT_CHAIN_UNITID_BASE