counterparts to bus_dmamem_alloc() and bus_dmamem_free(). This allows
the caller to specify the size of the allocation instead of it defaulting
to the max_size field of the busdma tag.
This is intended to aid in converting drivers to busdma. Lots of
hardware cannot understand scatter/gather lists, which forces the
driver to copy the i/o buffers to a single contiguous region
before sending it to the hardware. Without these new methods, this
would require a new busdma tag for each operation, or a complex
internal allocator/cache for each driver.
Allocations greater than PAGE_SIZE are rounded up to the next
PAGE_SIZE by contigmalloc(), so this is not suitable for multiple
static allocations that would be better served by a single
fixed-length subdivided allocation.
Reviewed by: jake (sparc64)
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.
of them, and couple them by always performing all operations on all
present IOMMUs. This is required because with the current API there
is no way to determine on which bus a busdma operation is performed.
While being there, clean up the iommu code a bit.
This should be a step in the direction of allow some of larger machines
to work; tests have shown that there still seem to be problems left.
- 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.
support for managing both streaming caches on psycho pairs).
Use explicit bus space accesses instead of mapping the device memory into
kva.
Move DVMA allocation to the map creation/dma memory allocation functions.
