The DBDMA engine really just reads bytes from a producing device (IDE
in our case) and shoves these bytes into memory. It doesn't care whether
any alignment takes place or not.
Our code today however assumes that block accesses always happen on
sector (512 byte) boundaries. This is a fair assumption for most cases.
However, Mac OS X really likes to do unaligned, incomplete accesses
that it finishes with the next DMA request.
So we need to read / write the unaligned bits independent of the actual
asynchronous request, because that one can only handle 512-byte-aligned
data. We also need to cache these unaligned sectors until the next DMA
request, at which point the data might be successfully flushed from the
pipe.
Signed-off-by: Alexander Graf <agraf@suse.de>
Soon we will introduce intermediate processing pauses which will
allow the bottom half to restart a DMA request that couldn't be
fulfilled yet.
For that to work, move the processing variable into the io struct
which is what DMA providers work with.
While touching it, also change it into a bool
Signed-off-by: Alexander Graf <agraf@suse.de>
The DBDMA controller has a bottom half to asynchronously process DMA
request queues.
This bh was stored as a gross static variable. Move it into the device
struct instead.
While at it, move all users of it to the new generic kick function.
Signed-off-by: Alexander Graf <agraf@suse.de>
The DBDMA engine really is running all the time, waiting for input. However
we don't want to waste cycles constantly polling.
So introduce a kick function that data providers can call to notify the
DBDMA controller of new input.
Signed-off-by: Alexander Graf <agraf@suse.de>
We usually keep struct and constant definitions in header files. Move
them there to stay consistent and to make access to fields easier.
Signed-off-by: Alexander Graf <agraf@suse.de>
Many of these should be cleaned up with proper qdev-/QOM-ification.
Right now there are many catch-all headers in include/hw/ARCH depending
on cpu.h, and this makes it necessary to compile these files per-target.
However, fixing this does not belong in these patches.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
