musb: Implement mode1 dma reads, conditionalized on CONFIG_MUSB_DMA_MODE1

Mode1 does all the full packet transfers using the dma engine,
rather than mode0 which required the CPU to do copy out the
packet from the receive buffer after each is received.  It's
a bit trickier to implement because the last packet is generally
not full size and you need to handle that specially (we do
the last transfer using mode0 dma).

Change-Id: I1791cb746ee424c5ce5713af2156dd30ea468da9
Signed-off-by: Mike J. Chen <mjchen@google.com>
1 file changed