serial: imx: Add support for KGDB's FIQ/NMI modedev/kdb-fiq

This patch makes it possible to use the imx uart with KGDB's FIQ/NMI
mode.

Main changes are:

.poll_init() will, if KGDB+FIQ are enabled, perform deeper hardware
initialization to ensure the serial port is always active (required
otherwise FIQ is not triggered by UART activity). This has an impact on
power usage so it is conservatively enabled.

imx_put_poll_char() has been simplified to remove the code to disable
interrupts. The present code can corrupt register state when re-entered
from FIQ handler.

Both imx_put_poll_char() and imx_get_poll_char() adopt _relaxed()
MMIO functions (which are safe for polled I/O and needed to avoid taking
spin locks).

Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org
Acked-by: Dirk Behme <dirk.behme@de.bosch.com>

0 files changed, 0 insertions, 0 deletions