Skip to content

Latest commit

 

History

History
78 lines (55 loc) · 2.9 KB

gpiodev.md

File metadata and controls

78 lines (55 loc) · 2.9 KB

gpiodev.py

gpiodev.py acts as a GPIO CharDev backend to record and verify GPIO updates.

It can be used to run regression tests and verify that the guest emits a predefined sequence of GPIO updates.

Usage

usage: gpiodev.py [-h] [-p PORT] [-c CHECK] [-r RECORD] [-e END] [-q] [-s] [-t] [-v] [-d]

GPIO device tiny simulator.

options:
  -h, --help            show this help message and exit
  -p PORT, --port PORT  remote host TCP port (defaults to 8007)
  -c CHECK, --check CHECK
                        input file to check command sequence
  -r RECORD, --record RECORD
                        output file to record command sequence
  -e END, --end END     emit the specified value to trigger remote exit on last received command
  -q, --quit-on-error   exit on first error
  -s, --single          run once: terminate once first remote disconnects
  -t, --log-time        emit time in log messages
  -v, --verbose         increase verbosity
  -d, --debug           enable debug mode

Arguments

  • -d only useful to debug the script, reports any Python traceback to the standard error stream.

  • -p specify an alternative TCP port to listen for incoming QEMU CharDev socket requests

  • -c specify a pre-recorded GPIO backend text file - which only contains ASCII characters and compare that incoming GPIO requests against the recorded data

  • -r specify a file to record incoming GPIO requests

  • -e emit a pre-defined GPIO input command - sent to the QEMU GPIO CharDev backend - that may be recognized by the QEMU guest code as a special marker to end a test sequence. Requires the check option for detecting the last expected GPIO request.

  • -q close the QEMU socket connection on first error or mismatched GPIO request when used with the check option.

  • -s quite the script on the first QEMU socket disconnection. Default is to listen for a new QEMU CharDev socket connection, restarting from a fresh state.

  • -t add time to log messages

  • -v can be repeated to increase verbosity of the script, mostly for debug purpose.

Exit Status

This script returns 0 if no error has been detected, or 1 if an error has been detected or the GPIO command stream has not been validated against the check file if any.

Examples

With the following examples:

-chardev socket,id=gpio,host=localhost,port=8007 -global ot-gpio-$OTMACHINE.chardev=gpio has been added to the QEMU command line to connect the GPIO backend to the incoming socket opened from the script. See the GPIO documentation for details and the role of the OTMACHINE environment variable.

  • Record a GPIO request sequence

    ./scripts/opentitan/gpiodev.py -vv -r gpio.txt -s

  • Check a GPIO request sequence against a previously record one, then triggers a VM guest app triggered termination by setting GPIO 31 to a high level.

    ./scripts/opentitan/gpiodev.py -vv -c gpio.txt -s -e 0x8000_0000