Previously, processing of arrow keys and control characters was done
in the interrupt handler itself. This increased the impact of UART
input on other interrupts and high-priority tasks. It also makes it
harder to implement DMA-based UART input on STM32L (in an imminent
CL), since the processing affected the circular UART input buffer
in-place.
This change turns uart_buffering.c back into a dumb I/O buffering
module, and puts all the command line editing and history support into
console.c.
Console history is done via a simple array of input lines instead of a
packed circular buffer of characters. This is a little less
RAM-efficient, but is easier to implement and read. History depth is
controlled via CONFIG_CONSOLE_HISTORY, and is 3 for STM32F and 8 for
other platforms. If we really need a greater history depth, we can
look into implementing a packed circular buffer again, but this time
at task time in console.c. Also added a 'history' command to print
the current console history.
BUG=chrome-os-partner:20485
BRANCH=none
TEST=console_edit unit test passes; 'history' command prints the last commands
Change-Id: I142a0be0d67718c58341e4569f4e2908f191d8b0
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/64363
Reviewed-by: Vic Yang <victoryang@chromium.org>
889f7bdd3b