BlackMark
321ff8a4ee
pureboot_device and the tsb device, C until now, rewritten in C++23 with every modeled behavior intact — the PGERS Z-mask and m48-discard ioctl wraps, the GPIO bridge's timing and pacing, the tiny NVM's write-once buffer, pin ownership, and the PB_PTY/TSB_PTY lines the harnesses parse. The one linkage fact worth a comment: simavr's parts headers (uart_pty.h) carry no C++ guards where its core headers do, so those includes sit in an extern "C" block. Warning-clean at -Wall -Wextra on the build line; the full protocol suites on all four sim-driven chips prove the conversion. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
74 lines
2.8 KiB
Python
74 lines
2.8 KiB
Python
#!/usr/bin/env python3
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"""Hand-over with a USART left enabled on the loader's own pins.
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A software or autobaud link deployed on a USART's TxD is mute if an
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application hands over with that USART still enabled: TXEN keeps the USART
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owning the pin, so the bit-banged transmitter's port writes go nowhere and the
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loader receives and obeys while answering nothing. The link's init releases it.
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The state is reached the way silicon reaches it — an application that sets up
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its USART and jumps in with no reset between, so nothing clears UCSRnB for it.
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The pin ownership itself is modelled by the device runner: simavr wires a
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USART through IRQs alone and never takes the pin from the port, so without
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that the mute could not happen here at all (test/pureboot_device.cpp).
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Usage: pbmute.py <device_bin> <pureboot_elf> <mcu> <hz> <base_hex> <page>
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<baud> <app_bin> <tool_py> <workdir> <link>
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"""
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import os
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import sys
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def fail(message):
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print(f"FAIL: {message}")
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sys.exit(1)
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def main():
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device_bin, elf, mcu, hz, base_hex, page, baud, app_bin, tool, workdir, link = sys.argv[1:]
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page, baud = int(page), int(baud)
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sys.path.insert(0, os.path.dirname(os.path.abspath(tool)))
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sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
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import pbsim
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import pureboot as pb
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if "@" not in link:
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fail(f"the link {link} names no owning USART — nothing would be under test")
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os.makedirs(workdir, exist_ok=True)
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dump = os.path.join(workdir, "dump.bin")
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device = pbsim.Device(device_bin, elf, mcu, hz, base_hex, page, baud, dump, link=link)
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try:
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port = pb.Port(device.pty, baud)
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loader = pb.Loader(port)
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loader.connect(25)
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resident = loader.info.version
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# Install the fixture and let it take over. It brings up the USART
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# that owns these pins and jumps straight back in.
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pb.op_flash(loader, app_bin, erase=False, verify=True)
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loader.run_application()
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# The loader is running again with that USART enabled behind it. Only
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# the release makes it audible; without it the connect times out.
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loader = pb.Loader(port)
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try:
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loader.connect(25)
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except pb.Error as error:
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fail(f"the loader never answered after the hand-over — the USART still owns its TX pin ({error})")
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if loader.info.version != resident:
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fail(f"identity changed across the hand-over: {resident} then {loader.info.version}")
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# Answering is not enough: it has to still be a working loader.
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pb.verify_pages(loader, pb.plan_flash(open(app_bin, "rb").read(), loader.info))
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port.close()
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finally:
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device.stop()
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print("pbmute: a loader on a USART's own pins answers after a hand-over that left it enabled")
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if __name__ == "__main__":
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main()
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