Fixes for a number of problems in the IOMMU code:

1.) Fix an off-by-one in the DVMA space handling, which would make it
    possible to allocate one page beyond the end of the DVMA area.
    This page was aliased to the first page. Apparently, this bug was
    responsible for the trashed nvram/eeprom some people were reporting,
    in conjunction with a number of unfortunate coincidences.
2.) Fix broken boundary and and lowaddr calculations.
3.) Fix a memory leak on an error path.
4.) Update a outdated comment to reflect the introduction of IOMMU_MAX_PRE,
    make the usage of IOMMU_MAX_PRE more consistent and KASSERT that the
    preallocation size is not 0.
5.) Fix a case where an error return was lost.
6.) When signalling an error to the caller by invoking the callback, do
    not use a segment pointer of NULL for compatability with existing
    drivers.

Also, increase the maximum segment number to 64; it is rather arbitrary,
with the exception of the of the stack space consumed by the segment
array.

Special thanks go to Harti Brandt <brandt@fokus.fraunhofer.de> for
spotting 4 and 5, and testing many iterations of patches.

Pointy hats to:	tmm

1 files changed, 6 insertions, 1 deletions

diff --git a/sys/sparc64/include/bus_private.h b/sys/sparc64/include/bus_private.h
index 4b68ffd..6c3a86e 100644
--- a/sys/sparc64/include/bus_private.h
+++ b/sys/sparc64/include/bus_private.h
@@ -33,7 +33,12 @@
 
 #include <sys/queue.h>
 
-#define	BUS_DMAMAP_NSEGS	((BUS_SPACE_MAXSIZE / PAGE_SIZE) + 1)
+/*
+ * This is more or less arbitrary, except for the stack space consumed by
+ * the segments array. Choose more than ((BUS_SPACE_MAXSIZE / PAGE_SIZE) + 1),
+ * since in practice we could be map pages more than once.
+ */
+#define	BUS_DMAMAP_NSEGS	64
 
 struct bus_dmamap_res {
 	struct resource		*dr_res;