Files
bootloader/test/pbsim.py
BlackMark a977e507f3 pureboot: every deployment axis is a build parameter
Clock, baud, serial backend (hardware USART 0/1 or the software UART on
any pins) and the activation window all resolve through one CMake
function, pureboot_add_loader() in pureboot/CMakeLists.txt — the unit a
downstream project consumes. The default baud is the fastest standard
rate within 2.5 % (the same best-divisor search libavr's solver runs),
gated on software builds by the polled receiver's 100-cycles-a-bit
floor; every explicit pick is re-checked by the compile's static asserts.

The size matrix builds each axis that can move the image — backend x
clock ladder x USART instance, per chip — against the slot budget, and
two nondefault deployments run the whole protocol suite live: the 328P
on its shipped 1 MHz fuses over software serial on TX=PB1/RX=PB5
(pureboot.custom), and the 644A over USART1 (pureboot.usart1). The sim
runner takes -l to bridge any link, paces a fully quiet bridge toward
real time (a free-running 8 M-cycle window loses the reset-race knock),
and the fixture application speaks the deployment it is built for.

The loader itself shed bytes on the way: the return-address high byte
spelled through byteswap (the double swap folds to the one-byte pick),
the info-block address composed instead of bit_cast, and libavr's new
polled-UART helpers replacing the port's uart::detail reaches. Every
combination fits: 458-506 B across the megas' whole matrix, 470-484 B
on the tinies, 556-562 B in the 1284s' 1 KiB slot.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-21 23:42:57 +02:00

69 lines
2.4 KiB
Python

"""Shared simavr harness for the pureboot tests: spawn the device runner,
hand out its pty, restart it from a flash dump (the power-fail path), and
keep its chatter out of undrained pipes."""
import os
import signal
import subprocess
class Device:
def __init__(self, binary, elf, mcu, hz, base_hex, page, baud, dump, reset_hex=None, resume=None, link=None):
cmd = [binary]
if link:
cmd += ["-l", link]
cmd += [elf, mcu, hz, base_hex, str(page), str(baud), dump]
if reset_hex is not None or resume is not None:
# Chips without a hardware boot section — the tinies and the
# m48s — reset to address 0 like silicon; the boot-sectioned
# megas re-vector to the loader base (BOOTRST).
patch = not mcu.startswith("atmega") or mcu.startswith("atmega48")
cmd.append(reset_hex if reset_hex is not None else ("0" if patch else base_hex))
if resume is not None:
cmd.append(resume)
self.log = open(dump + ".log", "a")
self.proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=self.log, text=True)
self.dump = dump
self.pty = None
for _ in range(50):
line = self.proc.stdout.readline()
if not line:
break
if line.startswith("PB_PTY"):
self.pty = line.split()[1]
break
if not self.pty:
self.stop()
raise RuntimeError("device did not report a pty")
def reset(self):
"""The external reset line: SIGUSR1 re-enters at the reset vector."""
self.proc.send_signal(signal.SIGUSR1)
def power_fail(self):
"""SIGTERM: the runner dumps its flash and exits — the image a
restart resumes from."""
self.stop()
return self.dump
def stop(self):
self.proc.terminate()
try:
self.proc.wait(timeout=5)
except subprocess.TimeoutExpired:
self.proc.kill()
self.log.close()
def run_tool(tool, pty, baud, *args, timeout=180):
result = subprocess.run(
[os.environ.get("PYTHON", "python3"), tool, "--port", pty, "--baud", str(baud), "--wait", "25", *args],
capture_output=True,
text=True,
timeout=timeout,
)
print(result.stdout, end="")
if result.returncode != 0:
raise RuntimeError(f"tool exited {result.returncode}: {result.stderr.strip()}")
return result.stdout