svn commit: r257581 - projects/altix2/sys/ia64/sgisn

[Marcel Moolenaar]

Author: marcel
Date: Sun Nov  3 18:14:46 2013
New Revision: 257581
URL: http://svnweb.freebsd.org/changeset/base/257581

Log:
  o   Update copyright
  o   Add a comment explaining what's happening with the PCI bridge discovery
      and in particular the conditional involving the NASID.

Modified:
  projects/altix2/sys/ia64/sgisn/sgisn_shub.c

Modified: projects/altix2/sys/ia64/sgisn/sgisn_shub.c
==============================================================================
--- projects/altix2/sys/ia64/sgisn/sgisn_shub.c	Sun Nov  3 17:19:17 2013	(r257580)
+++ projects/altix2/sys/ia64/sgisn/sgisn_shub.c	Sun Nov  3 18:14:46 2013	(r257581)
@@ -1,5 +1,5 @@
 /*-
- * Copyright (c) 2011 Marcel Moolenaar
+ * Copyright (c) 2011-2013 Marcel Moolenaar
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -474,6 +474,14 @@ sgisn_shub_attach(device_t dev)
 			if (r.sal_status != 0 || addr == 0)
 				continue;
 
+			/*
+			 * Filter PCI bridges not connected to the SHub
+			 * instance in question. We use the NASID to match
+			 * bridges to SHubs.
+			 * Note that the TIOCP bridge has bit 0 of the
+			 * NASID set, which is why we want to ignore bit 0.
+			 * Subtracting 1 from the mask does the trick.
+			 */
 			fwbus = (void *)IA64_PHYS_TO_RR7(addr);
 			if (((fwbus->bus_base >> sc->sc_nasid_shft) &
 			    (sc->sc_nasid_mask - 1)) != sc->sc_nasid)