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)
- 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.
to a new architecture. This is the base of the sparc64 port, but contains
limited machine dependent code, and can be used a base for ports. Included
are:
- standard machine dependent headers, tweaked for a 64 bit, big endian
architecture, including empty versions of all the machine dependent
structures
- a machine independent atomic.h, which can be used until a port has
support for interrupts and the operations really need to be atomic
- stub versions of all the machine dependent functions, which panic
when called and print out the name of the function that needs to
be implemented. functions which are normally in assembly files are
not included, but this should reduce the number of different undefined
references on the first few compiles from hundreds to 5 or 6
Given minimal startup code and console support it should be trivial to
make this compile and run the first few sysinits on almost any architecture.
Requested by: alfred, imp, jhb
