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 Update a outdated comment to reflect the introduction of IOMMU_MAX_PRE,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
map. Use this new feature to implement iommu_dvmamap_load_mbuf() and
iommu_dvmamap_load_uio() functions in terms of a new helper function,
iommu_dvmamap_load_buffer(). Reimplement the iommu_dvmamap_load()
to use it, too.
This requires some changes to the map format; in addition to that,
remove unused or redundant members.
Add SBus and Psycho wrappers for the new functions, and make them
available through the respective DMA tags.
_nexus_dmamap_load_buffer()
- implement nexus_dmamap_load() in terms of _nexus_dmamap_load_buffer().
Note that this is untested, as this code is not currently used (but
might be later for UPA devices).
- move BUS_DMAMAP_NSEGS to bus_private.h
- disable the ecache flushing in nexus_dmamap_sync(); it should not be
needed, although the docs are not entirely clear on that.
- change the IOMMU support code so that it supports overcommittting the
available DVMA memory, while still allocating as lazily as possible.
This is achieved by limiting the preallocation, and deferring the
allocation to map load time when it fails. In the latter case, the
DVMA memory reserved for unloaded maps can be stolen to free up enough
memory for loading a map.
- allow NULL settings in the method tables, and search the parent tags
until an appropriate implementation is found. This allows to remove some
kluges in the old implementation.
