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Date:      Mon, 6 Jan 2014 01:51:08 +0000 (UTC)
From:      Marcel Moolenaar <marcel@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-projects@freebsd.org
Subject:   svn commit: r260362 - projects/altix2/sys/ia64/sgisn
Message-ID:  <201401060151.s061p8gj085830@svn.freebsd.org>
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Author: marcel
Date: Mon Jan  6 01:51:08 2014
New Revision: 260362
URL: http://svnweb.freebsd.org/changeset/base/260362

Log:
  Fix precious commit. In "productizing" the code, the following went
  wrong:
  1.  The loop termination check was removed, resulting in an infinite
      loop.
  2.  The loop termination changed from a return to a break, actually
      causing the tail end of the shub_ptc() function to execute and
      causing panics there due to sc being re-used.
  
  Now that we properly wait for the PTC operation to complete, fix the
  loop termination condition by masking off bits we don't care for.
  Without it we end up in another infinite loop.
  
  Sheez...

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	Mon Jan  6 00:52:39 2014	(r260361)
+++ projects/altix2/sys/ia64/sgisn/sgisn_shub.c	Mon Jan  6 01:51:08 2014	(r260362)
@@ -613,7 +613,7 @@ void
 shub_ptc(vm_offset_t va, u_int rid)
 {
 	device_t dev;
-	struct sgisn_shub_softc *sc;
+	struct sgisn_shub_softc *sc, *scx;
 	uint64_t cfg0, cfg1, ptc, ws, wsreg;
 	u_int mynas, nasid, shub1;
 
@@ -640,16 +640,18 @@ shub_ptc(vm_offset_t va, u_int rid)
 		if (nasid == mynas)
 			goto next;
 		dev = devclass_get_device(sgisn_shub_devclass, nasid >> 1);
-		sc = (dev != NULL) ? device_get_softc(dev) : NULL;
-		if (sc == NULL)
+		if (dev == NULL)
+			break;
+		scx = device_get_softc(dev);
+		if (scx == NULL)
 			goto next;
 		if (shub1) {
-			bus_space_write_8(sc->sc_tag, sc->sc_hndl,
+			bus_space_write_8(scx->sc_tag, scx->sc_hndl,
 			    SHUB_MMR_PTC_CFG0, cfg0);
-			bus_space_write_8(sc->sc_tag, sc->sc_hndl,
+			bus_space_write_8(scx->sc_tag, scx->sc_hndl,
 			    SHUB_MMR_PTC_CFG1, cfg1);
 		} else
-			bus_space_write_8(sc->sc_tag, sc->sc_hndl,
+			bus_space_write_8(scx->sc_tag, scx->sc_hndl,
 			    SHUB_MMR_PTC(rid), ptc);
 	 next:
 		nasid += 2;
@@ -668,7 +670,7 @@ shub_ptc(vm_offset_t va, u_int rid)
 	while (1) {
 		ws = bus_space_read_8(sc->sc_tag, sc->sc_hndl, wsreg);
 		KASSERT((ws & 2) == 0, ("%s: deadlock detected", __func__));
-		if ((ws >> 56) == ((shub1) ? 0x3f : 0))
+		if (((ws >> 56) & 0x3f) == ((shub1) ? 0x3f : 0))
 			return;
 		cpu_spinwait();
 	}

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