Previously all access to the queue was done by adding or removing units
with no access to the underlying byte array, or ability to notify the
queue that the byte array had been updated. This prevented direct DMA
transfers to and from the underlying byte array.
This change adds a new struct, a queue_chunk, that represents a
contiguous region of the queues byte array. Regions of valid units as
well as free space can be requested. And there are now update functions
to signal to the queue that new units were added or existing units were
read from these chunks. A chunk can be queried and used to initialize
a DMA transfer, as interrupts or polling indicates that the DMA is
working the queue indicies can be updated and the policy activated as
needed.
Signed-off-by: Anton Staaf <robotboy@chromium.org>
BRANCH=None
BUG=None
TEST=make buildall -j
Change-Id: I7e37d937c56153122f0a3c73ba8064b656106e3a
Reviewed-on: https://chromium-review.googlesource.com/285556
Trybot-Ready: Anton Staaf <robotboy@chromium.org>
Tested-by: Anton Staaf <robotboy@chromium.org>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Commit-Queue: Anton Staaf <robotboy@chromium.org>
Previously there was no way to remove multiple units at a time
from the queue, and the queue was wasting an entry to disambiguate
full from empty. There was also no way to get the free entry
count from the queue, only the ability to query if it was above
a required amount. The queue was also storing its constant
compile time configuration as well as its dynamic state in the
same structure. This wasted RAM on configuration information
that doesn't change.
This refactor fixes these issues, making the queue suitable for
use in the new USART stream driver.
Signed-off-by: Anton Staaf <robotboy@chromium.org>
BRANCH=None
BUG=None
TEST=make buildall -j
Change-Id: I284cee52d8189928dbc4c499f87ab34e14019e5a
Reviewed-on: https://chromium-review.googlesource.com/210533
Reviewed-by: Vic Yang <victoryang@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Commit-Queue: Anton Staaf <robotboy@chromium.org>
Tested-by: Anton Staaf <robotboy@chromium.org>
