firewire: fw-ohci: check for misconfigured bus (phyID == 63)

Check NodeID.nodeNumber as per OHCI 1.1 clause 7.2.3.2.  See also IEEE
1394a table 5B-1.

Also, demote the "node ID not valid" message from error to notification
as it is not an error condition.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

drivers/firewire/fw-ohci.c

@@ -917,10 +917,15 @@ static void bus_reset_tasklet(unsigned long data)
 
 	reg = reg_read(ohci, OHCI1394_NodeID);
 	if (!(reg & OHCI1394_NodeID_idValid)) {
-		fw_error("node ID not valid, new bus reset in progress\n");
+		fw_notify("node ID not valid, new bus reset in progress\n");
 		return;
 	}
-	ohci->node_id = reg & 0xffff;
+	if ((reg & OHCI1394_NodeID_nodeNumber) == 63) {
+		fw_notify("malconfigured bus\n");
+		return;
+	}
+	ohci->node_id = reg & (OHCI1394_NodeID_busNumber |
+			       OHCI1394_NodeID_nodeNumber);
 
 	/*
 	 * The count in the SelfIDCount register is the number of

drivers/firewire/fw-ohci.h

@@ -59,6 +59,8 @@
 #define   OHCI1394_LinkControl_cycleSource	(1 << 22)
 #define OHCI1394_NodeID                       0x0E8
 #define   OHCI1394_NodeID_idValid             0x80000000
+#define   OHCI1394_NodeID_nodeNumber          0x0000003f
+#define   OHCI1394_NodeID_busNumber           0x0000ffc0
 #define OHCI1394_PhyControl                   0x0EC
 #define   OHCI1394_PhyControl_Read(addr)	(((addr) << 8) | 0x00008000)
 #define   OHCI1394_PhyControl_ReadDone		0x80000000