1 files changed, 67 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/shared/pci/pci_bus_count.c b/c/src/lib/libbsp/shared/pci/pci_bus_count.c
new file mode 100644
index 0000000000..d0c7c80f54
--- /dev/null
+++ b/c/src/lib/libbsp/shared/pci/pci_bus_count.c
@@ -0,0 +1,67 @@
+/*
+ * This software is Copyright (C) 1998 by T.sqware - all rights limited
+ * It is provided in to the public domain "as is", can be freely modified
+ * as far as this copyight notice is kept unchanged, but does not imply
+ * an endorsement by T.sqware of the product in which it is included.
+ */
+
+#include <rtems.h>
+#include <rtems/pci.h>
+
+static uint8_t pci_number_of_buses = 0xff;
+
+unsigned char pci_bus_count(void)
+{
+  if ( pci_number_of_buses != 0xff ) {
+    return pci_number_of_buses;
+  }
+
+  uint8_t  bus;
+  uint8_t  device;
+  uint8_t  function;
+  uint8_t  number_of_functions;
+  uint8_t  header = 0;
+  uint8_t  buses = 0;
+  uint32_t vendor = 0;
+  uint32_t class_rev = 0;
+
+  pci_number_of_buses = 0;
+
+  for (bus=0; bus < 0xff; bus++) {
+    for (device=0; device < PCI_MAX_DEVICES; device++) {
+
+       pci_read_config_dword(bus, device, 0, PCI_VENDOR_ID, &vendor);
+       if ( vendor == -1 ) {
+         continue;
+       }
+
+       pci_read_config_byte(bus, device, 0, PCI_HEADER_TYPE, &header);
+       number_of_functions = (header & 0x80) ? PCI_MAX_FUNCTIONS : 1;
+
+       for ( function=0; function < number_of_functions; function++ ) {
+         pci_read_config_dword(bus, device, function, PCI_VENDOR_ID, &vendor);
+         if ( vendor == -1 ) {
+           continue;
+         }
+
+         pci_read_config_dword(bus, device, function, PCI_CLASS_REVISION, &class_rev);
+         if ( (class_rev >> 16) == PCI_CLASS_BRIDGE_PCI ) {
+            pci_read_config_byte(bus, device, function, PCI_SUBORDINATE_BUS, &buses);
+            if ( buses > pci_number_of_buses ) {
+              pci_number_of_buses = buses;
+            }
+         }
+       }
+    }
+  }
+
+  if ( pci_number_of_buses == 0 ) {
+    printk("pci_bus_count() found 0 busses, assuming 1\n");
+    pci_number_of_buses = 1;
+  } else if ( pci_number_of_buses == 0xff ) {
+    printk("pci_bus_count() found 0xff busses, assuming 1\n");
+    pci_number_of_buses = 1;
+  }
+
+  return pci_number_of_buses;
+}