ci/bare-metal: Convert the main cros-servo boot code to python

Switching this part to python makes the code clearer and cleans up our
logs as well.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6398>

.gitlab-ci/bare-metal/cros_servo_run.py

@@ -0,0 +1,87 @@
+#!/usr/bin/env python3
+#
+# Copyright © 2020 Google LLC
+#
+# Permission is hereby granted, free of charge, to any person obtaining a
+# copy of this software and associated documentation files (the "Software"),
+# to deal in the Software without restriction, including without limitation
+# the rights to use, copy, modify, merge, publish, distribute, sublicense,
+# and/or sell copies of the Software, and to permit persons to whom the
+# Software is furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice (including the next
+# paragraph) shall be included in all copies or substantial portions of the
+# Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+# IN THE SOFTWARE.
+
+import argparse
+import re
+from serial_buffer import SerialBuffer
+import sys
+
+class CrosServoRun:
+    def __init__(self, cpu, ec):
+        self.ec_ser = SerialBuffer(ec, "artifacts/serial-ec.txt", "R SERIAL-EC> ")
+        self.cpu_ser = SerialBuffer(cpu, "artifacts/serial.txt", "R SERIAL-CPU> ")
+
+    def ec_write(self, s):
+        print("W SERIAL-EC> %s" % s)
+        self.ec_ser.serial.write(s.encode())
+
+    def cpu_write(self, s):
+        print("W SERIAL-CPU> %s" % s)
+        self.cpu_ser.serial.write(s.encode())
+
+    def run(self):
+        # Flush any partial commands in the EC's prompt, then ask for a reboot.
+        self.ec_write("\n")
+        self.ec_write("reboot\n")
+
+        # This is emitted right when the bootloader pauses to check for input.
+        # Emit a ^N character to request network boot, because we don't have a
+        # direct-to-netboot firmware on cheza.
+        for line in self.cpu_ser.lines():
+            if re.match("load_archive: loading locale_en.bin", line):
+                self.cpu_write("\016")
+                break
+
+        for line in self.cpu_ser.lines():
+            if re.match("---. end Kernel panic", line):
+                return 1
+            if re.match("POWER_GOOD not seen in time", line):
+                return 1
+
+            result = re.match("bare-metal result: (\S*)", line)
+            if result:
+                if result.group(1) == "pass":
+                    return 0
+                else:
+                    return 1
+
+        print("Reached the end of the CPU serial log without finding a result")
+        return 1
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--cpu', type=str, help='CPU Serial device', required=True)
+    parser.add_argument('--ec', type=str, help='EC Serial device', required=True)
+    args = parser.parse_args()
+
+    servo = CrosServoRun(args.cpu, args.ec)
+
+    retval = servo.run()
+
+    # power down the CPU on the device
+    servo.ec_write("power off\n")
+
+    sys.exit(retval)
+
+if __name__ == '__main__':
+    main()