Instead of using the timer/counter peripheral to handle the waiting time
and corresponding timeout, the USART peripheral internal timeout
mechanism is used.
This is particularly important for the SIMtrace board since there
(contrary to other boards) the I/O signal is not wired to a TIO pin
of the timer/counter block, and hence Rx/Tx data cannot reset that
timer/counter.
As a result of this migration, cardem is now supported not only on
owhw + qmod, but also on the simtrace board.
The guts of this change have been lifted out of Change-Id
Ibcb2c8cace9137695adf5fb3de43566f7cfb93b5 by Kevin Redon, which was
unfortunately touching various different topics at the same time and
hence was split up. Some improvements are the introduction of the
ENABLE_TX_TIMER_ONLY mode, which avoids the USART interrupt handler
getting hammered with TXRDY between release of RST and start of the ATR.
Change-Id: Ibcb2c8cace9137695adf5fb3de43566f7cfb93b5
Related: OS#1704
We now generalize the USB communiction and abandon the 'req_ctx'
structure inherited from openpcd. Instead we use the libosmocore 'msgb'
structure to handle incoming and outgoing USB tranfers. We also use
linuxlist-based msgb-queues for each endpoint.
