1 files changed, 29 insertions, 0 deletions
diff --git a/src/pci.c b/src/pci.c
index 5237f19..45f210d 100644
--- a/src/pci.c
+++ b/src/pci.c
@@ -185,6 +185,35 @@ pci_find_class(u16 classid)
     return -1;
 }
 
+int *PCIpaths;
+
+// Build the PCI path designations.
+void
+pci_path_setup(void)
+{
+    PCIpaths = malloc_tmp(sizeof(*PCIpaths) * 256);
+    if (!PCIpaths)
+        return;
+    memset(PCIpaths, 0, sizeof(PCIpaths));
+
+    int roots = 0;
+    int bdf, max;
+    foreachpci(bdf, max) {
+        int bus = pci_bdf_to_bus(bdf);
+        if (! PCIpaths[bus])
+            PCIpaths[bus] = (roots++) | PP_ROOT;
+
+        // Check if found device is a bridge.
+        u32 v = pci_config_readb(bdf, PCI_HEADER_TYPE);
+        v &= 0x7f;
+        if (v == PCI_HEADER_TYPE_BRIDGE || v == PCI_HEADER_TYPE_CARDBUS) {
+            v = pci_config_readl(bdf, PCI_PRIMARY_BUS);
+            int childbus = (v >> 8) & 0xff;
+            PCIpaths[childbus] = bdf | PP_PCIBRIDGE;
+        }
+    }
+}
+
 int pci_init_device(const struct pci_device_id *ids, u16 bdf, void *arg)
 {
     u16 vendor_id = pci_config_readw(bdf, PCI_VENDOR_ID);