[OpenBIOS] [PATCH 05/13] SPARC64: implement custom PCI bus scan for sabre

[Mark Cave-Ayland]

The sabre on-board devices are located at devfn (1,1) which means that in a
standard PCI bus scan the bus at devfn (1, 0) is enumerated first. This
doesn't play well with OpenBIOS which assumes that the ebus (with legacy
ioports) is mapped starting from io_base == 0x0.

Perform a custom scan to ensure that OpenBIOS doesn't crash when additional
devices are added to the bus at devfn (1, 0).

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland at ilande.co.uk>
---
 drivers/pci.c |   48 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 47 insertions(+), 1 deletion(-)

diff --git a/drivers/pci.c b/drivers/pci.c
index 27fb5f0..8b09d94 100644
--- a/drivers/pci.c
+++ b/drivers/pci.c
@@ -1263,6 +1263,39 @@ static void ob_scan_pci_bus(int *bus_num, unsigned long *mem_base,
 	}
 }
 
+#if defined(CONFIG_SPARC64)
+static void ob_scan_sabre_pci_bus(int *bus_num, unsigned long *mem_base,
+                            unsigned long *io_base, const char *path,
+                            int bus)
+{
+	int devnum, fn, is_multi;
+
+	PCI_DPRINTF("\nScanning sabre bus %d at %s...\n", bus, path);
+	
+	/* Horrible sabre hack: the PCI bridge with the on-board devices
+	   is located at devfn (1,1) so if we use the standard scan function
+	   we end up with our ioports not mapped at io_base == 0x0 which
+	   breaks many assumptions in OpenBIOS. Hence do a custom scan for
+	   sabre which does things in the right order. */
+	for (devnum = 0; devnum < 32; devnum++) {
+		is_multi = 0;
+		
+		if (devnum == 1) {
+			ob_configure_pci_device(path, bus_num, mem_base, io_base,
+				bus, 1, 1, &is_multi);
+			
+			ob_configure_pci_device(path, bus_num, mem_base, io_base,
+				bus, 1, 0, &is_multi);
+		} else {
+			for (fn = 0; fn==0 || (is_multi && fn<8); fn++) {
+				ob_configure_pci_device(path, bus_num, mem_base, io_base,
+					bus, devnum, fn, &is_multi);
+			}
+		}
+	}
+}
+#endif
+
 static void ob_configure_pci_bridge(pci_addr addr,
                                     int *bus_num, unsigned long *mem_base,
                                     unsigned long *io_base,
@@ -1314,10 +1347,23 @@ static void ob_configure_pci_bridge(pci_addr addr,
     pci_config_write8(addr, PCI_IO_LIMIT, (io_scan_limit >> 8) & ~(0xf));
 
     /* make pci bridge parent device, prepare for recursion */
+    
+#if defined(CONFIG_SPARC64)
+    /* Horrible hack for sabre */
+    int vid = pci_config_read16(addr, PCI_VENDOR_ID);
+    int did = pci_config_read16(addr, PCI_DEVICE_ID);
 
+    if (vid == PCI_VENDOR_ID_SUN && did == PCI_DEVICE_ID_SUN_SABRE) {
+        ob_scan_sabre_pci_bus(bus_num, mem_base, io_base,
+                        config->path, config->secondary_bus);       
+    } else {
+        ob_scan_pci_bus(bus_num, mem_base, io_base,
+                        config->path, config->secondary_bus);
+    }
+#else
     ob_scan_pci_bus(bus_num, mem_base, io_base,
                     config->path, config->secondary_bus);
-
+#endif
     /* bus scan updates *bus_num to last revealed pci bus number */
     config->subordinate_bus = *bus_num;
     pci_config_write8(addr, PCI_SUBORDINATE_BUS, config->subordinate_bus);
-- 
1.7.10.4